Cardiotoxicity is a well established complication of anticancer therapy. As cancer survivorship and life expectancy for cancer patients improves, the morbidity and mortality of anticancer therapy-related cardiotoxicity has become more problematic. It is of utmost importance to identify patients at the highest risk for the development of cardiotoxicity and to determine strategies for prevention, early detection and treatment.
Carfilzomib is an irreversible inhibitor of the constitutive proteasome and immunoproteasome. This phase I study evaluated the maximum-tolerated dose (MTD), pharmacokinetics, and pharmacodynamics of carfilzomib administered as a 30-minute intravenous (IV) infusion. Safety and efficacy of carfilzomib as a single agent or in combination with low-dose dexamethasone were assessed.
Cutaneous T-cell lymphomas (CTCLs) represent a group of hematopoietic malignancies that home to the skin and have no known molecular basis for disease pathogenesis. Sézary syndrome (SS) is the leukemic variant of CTCL. Currently, CTCL is incurable, highlighting the need for new therapeutic modalities. We have previously observed that combined small-molecule inhibition of protein kinase C-? (PKC?) and glycogen synthase kinase 3 (GSK3) causes synergistic apoptosis in CTCL cell lines and patient cells. Through microarray analysis of a SS cell line, we surveyed global gene expression following combined PKC?-GSK3 treatment to elucidate therapeutic targets responsible for cell death. Clinically relevant targets were defined as genes differentially expressed in SS patients that were modulated by combination-drug treatment of SS cells. Gene set enrichment analysis uncovered candidate genes enriched for an immune-cell signature, specifically the T-cell receptor and mitogen-activated protein kinase signaling pathways. Further analysis identified p38 as a potential therapeutic target that is overexpressed in SS patients and decreased by synergistic-inhibitor treatment. This target was verified through small-molecule inhibition of p38, leading to cell death in both SS cell lines and patient cells. These data establish p38 as a SS biomarker and a potential therapeutic target for the treatment of CTCL.Journal of Investigative Dermatology advance online publication, 25 September 2014; (2014) 0, 000-000. doi:10.1038/jid.2014.367.
There has been significant progress in the development of new anticancer therapies over the last decade.Targeted therapies, including anti-human epidermal growth factor receptor 2 agents, vascular endothelial growth factor inhibitors, and tyrosine kinase inhibitors, have been important components of current treatment strategies. However, many of these therapies have been associated with chemotherapy-related cardiac dysfunction. While newer targeted agents provide "on-target" anticancer activity, their "off-target" drug effects encompass a wide range of cardiovascular toxicities. Many of these toxicities are reversible, but they may limit the use and length of treatment and compromise its efficacy. Oncologists are often the first to diagnose chemotherapy-related cardiac dysfunction, although patients with advanced cardiotoxicity are referred to cardiologists for further care. The field of cardio-oncology has emerged as a necessary discipline to address these disabling complications. In order to prevent late-stage cardiotoxicity, an early collaborative effort between oncologists and cardiologists is warranted to risk-stratify patients prior to therapy and to treat at the earliest signs of cardiotoxicity. It is therefore of utmost importance for oncologists to be aware of the cardiotoxicities of anticancer therapies, and to be familiar with modifiable risk factors and early interventions that can prevent long-term cardiac damage.
Eosinophil accumulation is a defining feature of the immune response to parasitic worm infection. Tissue-resident cells, such as epithelial cells, are thought to initiate eosinophil recruitment. However, direct recognition of worms by eosinophils has not been explored as a mechanism for amplifying eosinophil accumulation. Here, we report that eosinophils rapidly migrate toward diverse nematode species in three-dimensional culture. These include the mammalian parasite Nippostrongylus brasiliensis and the free-living nematode Caenorhabditis elegans. Surprisingly, collective migration toward worms requires paracrine leukotriene B4 signaling between eosinophils. In contrast, neutrophils show a minimal response to nematodes, yet are able to undergo robust leukotriene-dependent migration toward IgG-coated beads. We further demonstrate that eosinophils accumulate around C. elegans in the lungs of mice. This response is not dependent on bacterial products, CCR3, or complement activation. However, mice deficient in leukotriene signaling show markedly attenuated eosinophil accumulation after injection of C. elegans or N. brasiliensis. Our findings establish that nematode-derived signals can directly induce leukotriene production by eosinophils and that leukotriene signaling is a major contributor to nematode-induced eosinophil accumulation in the lung. The similarity of the eosinophil responses to diverse nematode species suggests that conserved features of nematodes are recognized during parasite infection.
Chronic lymphocytic leukemia (CLL) remains fatal due to the development of resistance to existing therapies. Targeting abnormal glucose metabolism sensitizes various cancer cells to chemotherapy and/or elicits toxicity. Examination of glucose dependency in CLL demonstrated variable sensitivity to glucose deprivation. Further evaluation of metabolic dependencies of CLL cells resistant to glucose deprivation revealed increased engagement of fatty acid oxidation upon glucose withdrawal. Investigation of glucose transporter expression in CLL reveals up-regulation of glucose transporter GLUT4. Treatment of CLL cells with human immunodeficiency (HIV) protease inhibitor ritonavir, which inhibits GLUT4, elicits toxicity similar to that elicited upon glucose deprivation. CLL cells resistant to ritonavir are sensitized by co-treatment with metformin, potentially targeting compensatory mitochondrial complex 1 activity. Ritonavir and metformin have been administered in humans for the treatment of diabetes in patients with HIV, demonstrating the tolerance to this combination in humans. Our studies strongly substantiate further investigation of Food and Drug Administration approved ritonavir and metformin for CLL.
Brentuximab vedotin is an antibody-drug conjugate FDA-approved for the treatment of systemic anaplastic large-cell lymphoma (ALCL) that has relapsed after multiagent chemotherapy. At least 2 cases of hypersensitivity reactions to brentuximab vedotin have been reported, without attempted desensitization. This report describes a morbidly obese 32-year-old woman with ALCL that relapsed after autologous stem cell transplantation, who was treated on a phase II clinical study with brentuximab vedotin. After 1 dose, she experienced near-complete remission, but therapy was stopped because of severe drug-related toxicity. She then received 5 cytotoxic treatments and radiation, and ultimately experienced disease progression. The patient was rechallenged with brentuximab vedotin approximately 28 months after initial exposure and tolerated the dose well, but experienced a significant allergic reaction with the next dose. High-dose steroid and antihistamine prophylaxis administered 50 minutes before the subsequent brentuximab vedotin infusion was unsuccessful in mitigating this reaction. Brentuximab vedotin was successfully infused according to a rapid desensitization protocol. With progressive dose titration and supportive care, the patient tolerated this therapy. She received 11 doses through a rapid desensitization protocol and experienced a durable disease remission.
We investigated the safety, efficacy, and long-term outcomes of alemtuzumab and rituximab (AR) combination therapy in previously untreated patients with CLL. Thirty patients, ages 28-80 years, 47% older than 60 years, 90% Rai clinical stages II-IV, and 67% without favorable cytogenetics received AR. Based on the NCI-WG 1996 criteria, OR was 100%, with 60% CR. With CT scans OR was 70%, with 23% CR, 47% PR, and 30% SD. Sixty-seven percent of patients showed no evidence of MRD in the bone marrow by 6-color flow cytometry. Median PFS, TFS, and 5-year OS were 24.4, 50.7 months, and 80%, respectively. Grade 3/4 neutropenia and thrombocytopenia were reported in 30% and 7% of patients, respectively. CMV reactivation, asymptomatic in all but one patient, occurred in 8 patients. Immunotherapy with alemtuzumab and rituximab results in robust responses and long asymptomatic therapy-free intervals. It is well tolerated with infrequent, predictable, and easily managed complications.
The Epiducer lead delivery system is a novel lead delivery device that can be used to percutaneously implant S-Series paddle leads (St. Jude Medical, Plano, TX, USA) as well as multiple percutaneous leads obviating the need for laminectomy and/or multiple needle sticks, respectively. This study evaluates the safety and usage of the Epiducer lead delivery system.
Deregulated activation of ?-catenin in cancer has been correlated with genomic instability. During thymocyte development, ?-catenin activates transcription in partnership with T-cell-specific transcription factor 1 (Tcf-1). We previously reported that targeted activation of ?-catenin in thymocytes (CAT mice) induces lymphomas that depend on recombination activating gene (RAG) and myelocytomatosis oncogene (Myc) activities. Here we show that these lymphomas have recurring Tcra/Myc translocations that resulted from illegitimate RAG recombination events and resembled oncogenic translocations previously described in human T-ALL. We therefore used the CAT animal model to obtain mechanistic insights into the transformation process. ChIP-seq analysis uncovered a link between Tcf-1 and RAG2 showing that the two proteins shared binding sites marked by trimethylated histone-3 lysine-4 (H3K4me3) throughout the genome, including near the translocation sites. Pretransformed CAT thymocytes had increased DNA damage at the translocating loci and showed altered repair of RAG-induced DNA double strand breaks. These cells were able to survive despite DNA damage because activated ?-catenin promoted an antiapoptosis gene expression profile. Thus, activated ?-catenin promotes genomic instability that leads to T-cell lymphomas as a consequence of altered double strand break repair and increased survival of thymocytes with damaged DNA.
A phase II multicenter trial was performed to evaluate single-agent lenalidomide in advanced, refractory mycosis fungoides/Sézary syndrome. Thirty-two patients were enrolled with a median of six prior treatment regimens, including a median of four systemic therapies. Patients achieved an overall response rate of 28% (9 patients); all partial responses. Median overall survival was 43 months, median progression-free survival was 8 months, and median duration of response was 10 months. No grade 4 toxicities occurred. Grade 3 adverse events included fatigue (22%), infection (9%), and leukopenia (3%). Patients were frequently unable to tolerate the 25mg starting dose of lenalidomide used in other hematologic malignancies due to fatigue, pain and transient flare reaction (TFR) as a contributory factor. TFR appeared to correlate with clinical response, but the small sample size limited definitive conclusions, and the underlying mechanisms of this reaction are not known. Data from correlative studies on peripheral blood samples suggest that the effects of lenalidomide could be associated with decreased circulating CD25+ T-cells and CD4+ T-cell numbers. Skin lesions showed a trend for increased CD8, CD25 and FoxP3 expression with decreased CD4:CD8 ratio. In conclusion, lenalidomide monotherapy demonstrated activity in refractory CTCL, along with acceptable toxicity. This study is registered at ClinicalTrials.gov, identifier NCT00466921.
Between 2006 and 2011, four new agents gained regulatory approval for the treatment of relapsed/refractory cutaneous T-cell lymphoma (CTCL) and peripheral T-cell lymphoma (PTCL). These new approvals, together with recent advances in both combination chemotherapy and transplant strategies, have made the landscape for treatment of these patients immensely complex. Multiple clinical trials are now underway, evaluating the role of combining new agents with existing drugs and regimens, both for untreated and relapsed/refractory CTCL and PTCL. Pending results of such trials, clinicians are generally left with incomplete data and competing therapies when tasked with the treatment of these patients. In this article, we will briefly review the labeled indications for new agents for CTCL and PTCL, but will focus on data from the last 1 to 2 years, and on data from ongoing clinical trials, with the hope that in doing so we can help elucidate difficult treatment decisions.
Pre-messenger RNA splicing is significantly changed in cancer cells leading to the expression of cancer-specific transcripts. These transcripts have the potential to be used as cancer biomarkers and also as targets for new therapeutic approaches. In addition, the cancer-specific transcripts have the potential to alter the drug response of the cancer cells creating a chemo-resistant state. This later property of alternative splicing presents a challenge to clinicians in the design of effective therapeutic regimens. When a patients cancer relapses it is frequently refractory to standard chemotherapies resulting in a poor clinical outcome. Therefore, understanding the mechanisms of how alternative splicing can lead to chemo-resistance is critical to the effective delivery of treatment. Here, we will discuss the impact of alternative splicing variants on drug metabolism and activation; on drug interactions with cell signaling pathways; and on cell death pathways in cancer therapeutics. In addition to the initial characterization of splicing variants, the mechanisms leading to alterations in splicing are being studied in the setting of chemo-resistance and will be discussed here. The promise of therapeutic intervention to obviate the impact of these splicing variants will significantly enhance treatment options for cancer patients.
Eosinophil accumulation is a characteristic feature of the immune response to parasitic worms and allergens. The cell surface carbohydrate-binding receptor Siglec-F is highly expressed on eosinophils and negatively regulates their accumulation during inflammation. Although endogenous ligands for Siglec-F have yet to be biochemically defined, binding studies using glycan arrays have implicated galactose 6-O-sulfate (Gal6S) as a partial recognition determinant for this receptor. Only two sulfotransferases are known to generate Gal6S, namely keratan sulfate galactose 6-O-sulfotransferase (KSGal6ST) and chondroitin 6-O-sulfotransferase 1 (C6ST-1). Here we use mice deficient in both KSGal6ST and C6ST-1 to determine whether these sulfotransferases are required for the generation of endogenous Siglec-F ligands. First, we characterize ligand expression on leukocyte populations and find that ligands are predominantly expressed on cell types also expressing Siglec-F, namely eosinophils, neutrophils, and alveolar macrophages. We also detect Siglec-F ligand activity in bronchoalveolar lavage fluid fractions containing polymeric secreted mucins, including MUC5B. Consistent with these observations, ligands in the lung increase dramatically during infection with the parasitic nematode, Nippostrongylus brasiliensis, which is known to induce eosinophil accumulation and mucus production. Surprisingly, Gal6S is undetectable in sialylated glycans from eosinophils and BAL fluid analyzed by mass spectrometry. Furthermore, none of the ligands we describe are diminished in mice lacking KSGal6ST and C6ST-1, indicating that neither of the known galactose 6-O-sulfotransferases is required for ligand synthesis. These results establish that ligands for Siglec-F are present on several cell types that are relevant during allergic lung inflammation and argue against the widely held view that Gal6S is critical for glycan recognition by this receptor.
There remains an unmet therapeutic need for patients with relapsed/refractory diffuse large B-cell lymphoma (DLBCL) and peripheral T-cell lymphoma (PTCL). We conducted a phase I/II trial with bortezomib (dose-escalated to 1·6 mg/m(2) ) given concurrently with gemcitabine (800 mg/m(2) ) days 1 + 8 q21 d. Of 32 patients, 16 each had relapsed/refractory PTCL and DLBCL. Median prior therapies were 3 and 35% had failed transplant. Among the first 18 patients, 67% experienced grade 3/4 neutropenia and/or grade 3/4 thrombocytopenia resulting in repeated treatment delays (relative dose intensity: 46%). Thus, the study was amended to give bortezomib and gemcitabine days 1 + 15 q28 d, which resulted in markedly improved tolerability. Among all patients, the overall response rate (ORR) was 24% with 19% complete remission (CR; intent-to-treat (ITT) ORR 16%, CR 13%), which met criteria for futility. The ORR for DLBCL was 10% (CR 10%) vs. 36% for PTCL (CR 27%). Among 6 PTCL patients treated on the modified schedule, ORR by ITT was 50% (CR 30%). Altogether, concurrent bortezomib/gemcitabine given days 1 + 8 q21 d was not tolerable, while modification to a bi-monthly schedule allowed consistent treatment delivery. Whereas efficacy of this combination was low in heavily pre-treated DLBCL, there was a signal of activity in relapsed/refractory PTCL utilizing the modified schedule.
The intrathecal administration of morphine sulfate has become an established alternative to oral opiate therapy for the treatment of chronic pain. Currently, Infumorph(®) is the only morphine sulfate approved by the US Food and Drug Administration for continuous intraspinal administration with an infusion pump. However, in order to achieve and maintain adequate pain relief, patients may require concentrations outside of those commercially available products resulting in the use of compounded morphine.
Multiple myeloma (MM) is a fatal plasma cell malignancy exhibiting enhanced glucose consumption associated with an aerobic glycolytic phenotype (i.e., the Warburg effect). We have previously demonstrated that myeloma cells exhibit constitutive plasma membrane (PM) localization of GLUT4, consistent with the dependence of MM cells on this transporter for maintenance of glucose consumption rates, proliferative capacity, and viability. The purpose of this study was to investigate the molecular basis of constitutive GLUT4 plasma membrane localization in MM cells.
Corneal epithelial wound repair involves the migration of epithelial cells to cover the defect followed by the proliferation of the cells to restore thickness. Heparan sulfate proteoglycans (HSPGs) are ubiquitous extracellular molecules that bind to a plethora of growth factors, cytokines, and morphogens and thereby regulate their signaling functions. Ligand binding by HS chains depends on the pattern of four sulfation modifications, one of which is 6-O-sulfation of glucosamine (6OS). SULF1 and SULF2 are highly homologous, extracellular endosulfatases, which post-synthetically edit the sulfation status of HS by removing 6OS from intact chains. The SULFs thereby modulate multiple signaling pathways including the augmentation of Wnt/ß-catenin signaling. We found that wounding of mouse corneal epithelium stimulated SULF1 expression in superficial epithelial cells proximal to the wound edge. Sulf1?/?, but not Sulf2?/?, mice, exhibited a marked delay in healing. Furthermore, corneal epithelial cells derived from Sulf1?/? mice exhibited a reduced rate of migration in repair of a scratched monolayer compared to wild-type cells. In contrast, human primary corneal epithelial cells expressed SULF2, as did a human corneal epithelial cell line (THCE). Knockdown of SULF2 in THCE cells also slowed migration, which was restored by overexpression of either mouse SULF2 or human SULF1. The interchangeability of the two SULFs establishes their capacity for functional redundancy. Knockdown of SULF2 decreased Wnt/ß-catenin signaling in THCE cells. Extracellular antagonists of Wnt signaling reduced migration of THCE cells. However in SULF2- knockdown cells, these antagonists exerted no further effects on migration, consistent with the SULF functioning as an upstream regulator of Wnt signaling. Further understanding of the mechanistic action of the SULFs in promoting corneal repair may lead to new therapeutic approaches for the treatment of corneal injuries.
Chronic lymphocytic leukemia (CLL) therapy has evolved over the past few decades as modern chemo-immunotherapy significantly improved the response and survival of CLL patients. However, treatment toxicity of the intensive chemo-immunotherapy often limits its use in the mostly elderly population of patients. Further, the disease eventually relapses and additional therapy options are required. Of particular interest are molecular targeted therapies that interfere with critical signal transduction pathways controlling cell growth and survival. This review will provide an update on the most recent preclinical and clinical development of signal transduction targeted therapy in CLL.
Strategies that block infiltration of leukocytes into the injured spinal cord improve sparing of white matter and neurological recovery. In this article, we examine the dependency of recovery on hematogenous depletion of neutrophils and monocytes. Mice were depleted of neutrophils or monocytes by systemic administration of anti-Ly6G or clodronate-liposomes. A third group was depleted of both subsets. Neurological improvement, based on a battery of tests of performance, and white matter sparing, occurred only in animals depleted of both neutrophils and monocytes. We also attempted to define the nature of the environment that was favorable to recovery. Hemeoxygenase-1 and malondialdehyde, markers of oxidative stress and lipid peroxidation, respectively, were reduced to similar levels in animals depleted of both neutrophils and monocytes, or only monocytes, but remained elevated in the group only depleted of neutrophils. Matrix metalloproteinase-9, a protease involved in early damage, was most strongly reduced in animals depleted of both leukocyte subsets. Finally, disruption of the blood-spinal cord barrier and abnormal nonheme iron accumulation were reduced only in animals depleted of both neutrophils and monocytes. Together, these findings indicate cooperation between neutrophils and monocytes in mediating early pathogenesis in the contused spinal cord and defining long-term neurological recovery.
Cancer therapies have led to remarkable results due to improved toxicity profiles and effects on survival. While these medical, surgical, and radiation protocols are chiefly responsible for these noteworthy contributions, an unexpected constellation of toxicities has emerged. Most notably, dermatologic adverse events have gained considerable attention, due to their high frequency, visibility, and impact on physical and psychosocial health, all of which affect dose intensity and possibly clinical outcome. Consequently, increased attention to cutaneous health in oncology has resulted in supportive oncodermatology clinical programs and toxicity-driven investigations, aiming to mitigate these untoward events and permit the continued optimization of cancer treatments.
Glucocorticoids (GCs) are widely used in the treatment of hematological malignancies such as multiple myeloma. However, the development of resistance to GCs limits their clinical utility. Response to GCs is dependent on an active glucocorticoid receptor, GR-?, expressed at wild-type levels in the GC-sensitive cell line (MM.1S). GC-resistant derivative cell lines MM.1Re and MM.1RL display significant downregulation of GR-? transcripts. In this study, we report that a luciferase reporter containing the 3-UTR of GR-? is significantly repressed in MM.1R cells when compared to MM.1S cells, suggesting that one or several microRNAs that are upregulated in MM.1R maybe in part responsible for the downregulation of the GR-? transcript. To examine posttranscriptional mechanisms of GR regulation, we examined miRNAs that have complimentary binding sites in the 3-UTR of GR-? and found miR-130b, miR-181a, and miR-636 to be differentially expressed between GC-sensitive and GC-resistant MM.1 cell lines. Overexpression of miR-130b in MM.1S cells results in decreased expression of endogenous GR protein and decreased activity of the luciferase reporter. In addition, in MM.1S cells, the downstream GC response of glucocorticoid-induced leucine zipper induction is decreased by the overexpression of miR-130b, and further miR-130b inhibits GC-induced apoptosis and causes resistance to GCs.
Temozolomide (TMZ) is an oral derivative of dacarbazine that induces DNA damage by methylating nucleotide bases. Resistance has been associated with high levels of O?-methylguanine-DNA methyltransferase (MGMT). Malignant CD4(+) T cells of patients with mycosis fungoides/Sézary syndrome (MF/SS) have been shown to have low levels of MGMT and may be particularly sensitive to this methylator.
Lymphoid-enhancer-binding factor 1 (LEF1), coupling with ?-catenin, functions as a key nuclear mediator of WNT/?-catenin signaling, which regulates cell proliferation and survival. LEF1 has an important role in lymphopoiesis, and is normally expressed in T and pro-B cells but not mature B cells. However, gene expression profiling demonstrates overexpression of LEF1 in chronic lymphocytic leukemia, and knockdown of LEF1 decreases the survival of the leukemic cells. So far, the data on LEF1 expression in B-cell lymphomas are limited. This study represents the first attempt to assess LEF1 by immunohistochemistry in a large series (290 cases) of B-cell lymphomas. Strong nuclear staining of LEF1 was observed in virtually all neoplastic cells in 92 of 92 (100%) chronic lymphocytic leukemia/small lymphocytic lymphomas including two CD5- cases, with strongest staining in cells with Richters transformation. LEF1 also highlighted the morphologically inconspicuous small lymphocytic lymphoma component in three composite lymphomas. All 53 mantle cell lymphomas, 31 low-grade follicular lymphomas and 31 marginal zone lymphomas, including 3 CD5+ cases, were negative. In 12 grade 3 follicular lymphomas, LEF1 was positive in a small subset (5-15%) of cells. Diffuse large B-cell lymphoma, however, demonstrated significant variability in LEF1 expression with overall positivity in 27 of 71 (38%) cases. Our results demonstrate that nuclear overexpression of LEF1 is highly associated with chronic lymphocytic leukemia/small lymphocytic lymphoma, and may serve as a convenient marker for differential diagnosis of small B-cell lymphomas. The expression of ?-catenin, the coactivator of LEF1 in WNT signaling, was examined in 50 chronic lymphocytic leukemia/small lymphocytic lymphomas, of which 44 (88%) showed negative nuclear staining. The findings of universal nuclear overexpression of LEF1 but lack of nuclear ?-catenin in the majority of chronic lymphocytic leukemia/small lymphocytic lymphoma suggest that the pro-survival function of LEF1 in this disease may be independent of WNT/?-catenin signaling.
This multicenter, single-arm, open-label non-randomized phase II trial (NCT00744991) was conducted in patients with recurrent/refractory mycosis fungoides (MF), stage IB-IVB, or Sézary syndrome (SS). A Simon two-stage design required 25 patients enrolled in stage 1 with ?7 confirmed objective responses for expansion into stage 2. Patients were treated with oral enzastaurin (250?mg twice daily) until disease progression or intolerable toxicity. The primary endpoint was investigator-assessed response rate; secondary endpoints were time to objective response, response duration, time-to-progression, patient-reported pruritus, and safety/tolerability. Twenty-five patients were enrolled. A partial response was observed in one patient with MF. Median time-to-progression was 78 and 44 days in MF and SS, respectively. Self-reported pruritus relief and improved composite pruritus-specific symptom scores were documented in six and four patients, respectively. Enzastaurin was well tolerated with mostly grade 1-2 adverse events, mainly diarrhea and fatigue. There were two adverse event-related drug discontinuations with one possibly treatment-related.
Peripheral T-cell lymphomas (PTCLs) are a heterogeneous group of clinically aggressive diseases associated with poor outcome. Studies that focus specifically on PTCL are emerging, with the ultimate goal of improved understanding of disease biology and the development of more effective therapies. However, one of the difficulties in classifying and studying treatment options in clinical trials is the rarity of these subtypes. Various groups have developed lymphoma classifications over the years, including the World Health Organization, which updated its classification in 2008. This article briefly reviews the major lymphoma classification schema, highlights contributions made by the collaborative International PTCL Project, discusses prognostic issues and gene expression profiling, and outlines therapeutic approaches to PTCL. These include the standard chemotherapeutic regimens and other modalities incorporating antifolates, conjugates, histone deacetylase inhibitors, monoclonal antibodies, nucleoside analogs, proteasome inhibitors, and signaling inhibitors. As this review emphasizes, the problem has now evolved into an abundance of drugs and too few patients available to test them. Collaborative groups will aid in future efforts to find the best treatment strategies to improve the outcome for patients with PTCL.
Cutaneous T-cell lymphomas (CTCL) represent a spectrum of several distinct non-Hodgkins lymphomas that are characterized by an invasion of the skin by malignant, clonal lymphocytes. Our laboratory has previously demonstrated that the protein kinase C (PKC) ? inhibitor Enzastaurin increases apoptosis in malignant lymphocytes of CTCL. These results directly led to a clinical trial for Enzastaurin in CTCL in which it was well tolerated and showed modest activity. To ascertain a means of improving the efficacy of Enzastaurin, we investigated complementary signaling pathways and identified glycogen synthase kinase-3 (GSK3) as important in survival signaling in CTCL. Enzastaurin combined with GSK3 inhibitors demonstrated an enhancement of cytotoxicity. Treatment with a combination of Enzastaurin and the GSK3 inhibitor AR-A014418 resulted in upregulation of ?-catenin total protein and ?-catenin-mediated transcription. Inhibition of ?-catenin-mediated transcription or small hairpin RNA (shRNA) knockdown of ?-catenin decreased the cytotoxic effects of Enzastaurin plus AR-A014418. In addition, treatment with Enzastaurin and AR-A014418 decreased the mRNA levels and surface expression of CD44. shRNA knockdown of ?-catenin also restored CD44 surface expression. Our observations provide a rationale for the combined targeting of PKC and GSK3 signaling pathways in CTCL to enhance the therapeutic outcome.
Lapatinib, a dual kinase inhibitor against epidermal growth factor receptor (EGFR) and human epidermal receptor two (HER2) has shown efficacy in treating HER2 positive breast cancer. Nanoparticle albumin bound (nab) paclitaxel was developed to reduce toxicities from paclitaxel and improve its efficacy. Thirty patients with stage I-III HER2 positive breast cancer were treated in the neoadjuvant setting with lapatinib 1,000 mg/day and nab-paclitaxel 260 mg/m(2) every 3 weeks for four cycles. The primary end point of the trial was clinical response rate (cRR) with secondary end points including pathologic complete response rate (pCR), tolerability of the combination, and marker response. The cRR was 82.8% (24 patients) with six (20.7%) patients having complete clinical response, 18 (62.1%) having partial clinical response, and five (17.2%) stable disease. A pCR was observed in five of the 28 patients (17.9%). The most frequent grade 2 toxicities were neuropathy in nine patients (30%), fatigue in seven patients (23.3%), rash in 11 patients (36.7%), and bone pain in 10 patients (33.3%). There was no significant drop in the left ventricular ejection fraction (LVEF). Of the tissue markers examined, we were not able to find a predictor of response. The combination of lapatinib and nab-paclitaxel was well tolerated and provided good efficacy in women with HER2 positive breast cancer. This combination offers an alternative non-anthracycline-containing regimen for women with HER2 positive breast cancer.
8-Aminoadenosine (8-NH(2)-Ado), a ribosyl nucleoside analog, in preclinical models of multiple myeloma inhibits phosphorylation of proteins in multiple growth and survival pathways, including Akt. Given that Akt controls the activity of mammalian target of rapamycin (mTOR), we hypothesized that 8-NH(2)-Ado would be active in mantle cell lymphoma (MCL), a hematological malignancy clinically responsive to mTOR inhibitors. In the current study, the preclinical efficacy of 8-NH(2)-Ado and its resulting effects on Akt/mTOR and extracellular-signal-regulated kinase signaling were evaluated using 4 MCL cell lines, primary MCL cells, and normal lymphocytes from healthy donors. For all MCL cell lines, 8-NH(2)-Ado inhibited growth and promoted cell death as shown by reduction of thymidine incorporation, loss of mitochondrial membrane potential, and poly (adenosine diphosphate-ribose) polymerase cleavage. The efficacy of 8-NH(2)-Ado was highly associated with intracellular accumulation of 8-NH(2)-adenosine triphosphate (ATP) and loss of endogenous ATP. Formation of 8-NH(2)-ATP was also associated with inhibition of transcription and translation accompanied by loss of phosphorylated (p-)Akt, p-mTOR, p-Erk1/2, p-phosphoprotein (p)38, p-S6, and p-4E-binding protein 1. While normal lymphocytes accumulated 8-NH(2)-ATP but maintained their viability with 8-NH(2)-Ado treatment, primary lymphoma cells accumulated higher concentrations of 8-NH(2)-ATP, had increased loss of ATP, and underwent apoptosis. We conclude that 8-NH(2)-Ado is efficacious in preclinical models of MCL and inhibits signaling of Akt/mTOR and Erk pathways.
L-selectin initiates lymphocyte interactions with high endothelial venules (HEVs) of lymphoid organs through binding to ligands with specific glycosylation modifications. 6-Sulfo sLe(x), a sulfated carbohydrate determinant for L-selectin, is carried on core 2 and extended core 1 O-glycans of HEV-expressed glycoproteins. The MECA-79 monoclonal antibody recognizes sulfated extended core 1 O-glycans and partially blocks lymphocyte-HEV interactions in lymphoid organs. Recent evidence has identified the contribution of 6-sulfo sLe(x) carried on N-glycans to lymphocyte homing in mice. Here, we characterize CL40, a novel IgG monoclonal antibody. CL40 equaled or surpassed MECA-79 as a histochemical staining reagent for HEVs and HEV-like vessels in mouse and human. Using synthetic carbohydrates, we found that CL40 bound to 6-sulfo sLe(x) structures, on both core 2 and extended core 1 structures, with an absolute dependency on 6-O-sulfation. Using transfected CHO cells and gene-targeted mice, we observed that CL40 bound its epitope on both N-glycans and O-glycans. Consistent with its broader glycan-binding, CL40 was superior to MECA-79 in blocking lymphocyte-HEV interactions in both wild-type mice and mice deficient in forming O-glycans. This superiority was more marked in human, as CL40 completely blocked lymphocyte binding to tonsillar HEVs, whereas MECA-79 inhibited only 60%. These findings extend the evidence for the importance of N-glycans in lymphocyte homing in mouse and indicate that this dependency also applies to human lymphoid organs.
Sulf-1 and Sulf-2 are extracellular endoglucosamine 6-sulfatases, which selectively liberate the 6-O-sulfate groups on glucosamines present in N, 6-O, and 2-O trisulfated disaccharides of intact heparan sulfate (HS)/heparin chains. The Sulfs are known to regulate signaling of heparin/HS-binding protein ligands, such as morphogens and growth factors, presumably through their ability to decrease the association between the ligands and HS proteoglycans. These enzymes serve important roles in development and are dysregulated in many cancers. We previously described arylsulfatase and endoglucosamine 6-sulfatase assays for the Sulfs. RB4CD12 is a phage display anti-HS antibody. N-sulfation, 2-O-sulfation, and 6-O-sulfation are involved in its binding. In this chapter, we describe the application of RB4CD12 in ELISA, flow cytometry, and immunohistochemistry assays to measure the enzymatic activity of the Sulfs. These newly established methods should facilitate further investigation of the Sulfs in vitro and in vivo.
Steroid hormone receptors (SHR) are crucial regulators of disease and the basis for clinical intervention in cancers. Recent evidence confirms that microRNAs (miRNAs) impact the pathobiology of hormone-regulated malignancies. Therefore, elucidating miRNA regulation of SHR expression and modulation of miRNAs by SHRs may provide diagnostic biomarkers or therapeutic targets.
Anaplastic large cell lymphoma (ALCL) is a biologic and clinically heterogenous subtype of T-cell lymphoma. Clinically, ALCL may present as localized (primary) cutaneous disease or widespread systemic disease. These two forms of ALCL are distinct entities with different clinical and biologic features. Both types share similar histology, however, with cohesive sheets of large lymphoid cells expressing the Ki-1 (CD30) molecule. Primary cutaneous ALCL (C-ALCL) is part of the spectrum of CD30+ lymphoproliferative diseases of the skin including lymphomatoid papulosis. Using conservative measures, 5-year disease-free survival rates are > 90%. The systemic ALCL type is an aggressive lymphoma that may secondarily involve the skin, in addition to other extranodal sites. Further, systemic ALCL may be divided based on the expression of anaplastic lymphoma kinase (ALK) protein, which is activated most frequently through the nonrandom t(2;5) chromosome translocation, causing the fusion of the nucleophosmin (NPM) gene located at 5q35 to 2p23 encoding the receptor tyrosine kinase ALK. Systemic ALK+ ALCLs have improved prognosis compared with ALK-negative ALCL, although both subtypes warrant treatment with polychemotherapy. Allogeneic and, to a lesser extent, autologous stem cell transplantation play a role in relapsed disease, while the benefit of upfront transplant is not clearly defined. Treatment options for relapsed patients include agents such as pralatrexate (Folotyn) and vinblastine. In addition, a multitude of novel therapeutics are being studied, including anti-CD30 antibodies, histone deacetylase inhibitors, immunomodulatory drugs, proteasome inhibitors, and inhibitors of ALK and its downstream signaling pathways. Continued clinical trial involvement by oncologists and patients is imperative to improve the outcomes for this malignancy.
Importance of the field: Sulf-1 and Sulf-2 are sulfatases that edit the sulfation status of heparan sulfate proteoglycans (HSPGs) on the outside of cells and regulate a number of critical signaling pathways. The Sulfs are dysregulated in many cancers with Sulf-2 in particular implicated as a driver of carcinogenesis in NSCLC, pancreatic cancer and hepatocellular carcinoma. Areas covered in this review: This review describes the novel activity of the Sulfs in altering the sulfation pattern of HSPG chains on the outside of cells. Thereby, the Sulfs can change the binding of growth factors to these chains and can either promote (e.g., Wnt) or inhibit (e.g., fibroblast growth factor-2) signaling. The review focuses on the widespread upregulation of both Sulfs in cancers and summarizes the evidence that Sulf-2 promotes the transformed behavior of several types of cancer cells in vitro as well as their tumorigenicity in vivo. What the reader will gain: Sulf-2 is a bonafide candidate as a cancer-causing agent in NSCLC and other cancers in which it is upregulated. Take home message: Sulf-2 is an extracellular enzyme and as such would be an attractive therapeutic target for the treatment of NSCLC and other cancers.
Cutaneous marginal zone lymphoma (MZL) may be a primary cutaneous condition or the result of secondary involvement from noncutaneous MZL. Distinguishing primary cutaneous MZL (PCMZL) from secondary cutaneous MZL (SCMZL) is of utmost importance for prognostic and therapeutic approach.
Gene-list annotations are critical for researchers to explore the complex relationships between genes and functionalities. Currently, the annotations of a gene list are usually summarized by a table or a barplot. As such, potentially biologically important complexities such as one gene belonging to multiple annotation categories are difficult to extract. We have devised explicit and efficient visualization methods that provide intuitive methods for interrogating the intrinsic connections between biological categories and genes.
We present the results of an open-label clinical trial and the clinical use of alemtuzumab in 19 heavily pretreated patients with advanced erythrodermic cutaneous T-cell lymphomas (CTCL) (erythrodermic mycosis fungoides and Sézary syndrome). Ten patients received alemtuzumab intravenously using an escalating dose regimen with a final dose of 30 mg three times weekly for 4 weeks followed by subcutaneous administration for 8 weeks. Nine patients were treated with only the SQ or IV dosing. The overall response rate was 84%, with 9 (47%) complete and 7 (37%) partial remissions. The median follow-up was 24 months (range, 6 to 62+ months). Median overall survival was 41 months whereas median progression free survival was 6 months. Minimal residual disease by T-cell gene rearrangement studies was detected in 11 patients who achieved complete response and partial response. Toxicities included myelosuppression and infections; however, the majority of side effects were of Grade 2 in severity and transient. One patient was diagnosed with a concurrent lymphoma (mantle cell lymphoma) 6 months after completing alemtuzumab therapy. Alemtuzumab is particularly effective in patients with erythrodermic CTCL with acceptable toxicities. Combined strategies with alemtuzumab may achieve molecular remissions with longer response durations.
Therapeutic strategies to enhance the efficacy of radioimmunotherapy have not been explored. Motexafin gadolinium is a novel anticancer agent that targets redox-dependent pathways and enhances sensitivity of tumor cells to ionizing radiation.
Heparan sulfates (HS) bind a diversity of protein ligands on the cell surface and in the extracellular matrix and thus can modulate cell signaling. The state of sulfation in glucosamines and uronic acids within the chains strongly influences their binding. We have previously cloned and characterized two human extracellular endoglucosamine 6-sulfatases, HSulf-1 and HSulf-2, which selectively liberate the 6-O sulfate groups on glucosamines present in N, 6-O, and 2-O trisulfated disaccharides of intact HS and heparins. These enzymes serve important roles in development and are upregulated in a number of cancers. To determine whether the Sulfs act on the trisulfated disaccharides that exist on the cell surface, we expressed HSulfs in cultured cells and performed a flow cytometric analysis with the RB4CD12, an anti-HS antibody that recognizes N- and O-sulfated HS saccharides. The endogenously expressed level of the cell surface RB4CD12 epitope was greatly diminished in CHO, HEK293, and HeLa cells transfected with HSulf-1 or HSulf-2 cDNA. In correspondence with the RB4CD12 finding, the N, 6-O, and 2-O trisulfated disaccharides of the HS isolated from the cell surface/extracellular matrix were dramatically reduced in the Sulf-expressed HEK293 cells. We then developed an ELISA and confirmed that the RB4CD12 epitope in immobilized heparin was degraded by purified recombinant HSulf-1 and HSulf-2, and conditioned medium (CM) of MCF-7 breast carcinoma cells, which contain a native form of HSulf-2. Furthermore, HSulf-1 and HSulf-2 exerted activity against the epitope expressed on microvessels of mouse brains. Both HSulf activities were potently inhibited by PI-88, a sulfated heparin mimetic with anti-cancer activities. These findings provide new strategies for monitoring the extracellular remodeling of HS by Sulfs during normal and pathophysiological processes.
Multiple myeloma, an incurable plasma cell malignancy, is characterized by altered cellular metabolism and resistance to apoptosis. Recent connections between glucose metabolism and resistance to apoptosis provide a compelling rationale for targeting metabolic changes in cancer. In this study, we have examined the ability of the purine analogue 8-aminoadenosine to acutely reduce glucose consumption by regulating localization and expression of key glucose transporters. Myeloma cells counteracted the metabolic stress by activating autophagy. Co-treatment with inhibitors of autophagy results in marked enhancement of cell death. Glucose consumption by drug-resistant myeloma cells was unaffected by 8-aminoadenosine, and accordingly, no activation of autophagy was observed. However, these cells can be sensitized to 8-aminoadenosine under glucose-limiting conditions. The prosurvival autophagic response of myeloma to nutrient deprivation or to nucleoside analogue treatment has not been described previously. This study establishes the potential of metabolic targeting as a broader means to kill and sensitize myeloma and identifies a compound that can achieve this goal.
In this issue of Blood, Hernandez Mir and colleagues provide the most detailed analysis to date of the glycans on an HEV-expressed ligand (CD34) isolated from a human lymphoid organ, (tonsils), adding to our understanding of how L-selectin mediates lymphocyte homing.
Sulf-1 and Sulf-2 are novel extracellular sulfatases that act on internal glucosamine 6-O-sulfate modifications within heparan sulfate proteoglycans and regulate their interactions with various signaling molecules, including Wnt ligands. Although the Sulfs are multidomain proteins, there is limited information available about how the subdomains contribute to their enzymatic and signaling activities. In this study, we found that both human Sulfs were synthesized as prepro-enzymes and cleaved by a furin-type proteinase to form disulfide-bond linked heterodimers of 75- and 50-kDa subunits. The mature Sulfs were secreted into conditioned medium, as well as retained on the cell membrane. Although the catalytic center resides in the N-terminal 75-kDa subunit, the C-terminal 50-kDa subunit was indispensable for both arylsufatase and glucosamine 6-O-sulfate-endosulfatase activity. We found that the hydrophilic regions of the Sulfs were essential for endosulfatase activity but not for arylsulfatase activity. Using Edman sequencing, we identified furin-type proteinase cleavage sites in Sulf-1 and Sulf-2. Deletion of these sequences resulted in uncleavable forms of Sulfs. The uncleavable Sulfs retained enzymatic activity. However, they were unable to potentiate Wnt signaling, which may be due to their defective localization into lipid rafts on the plasma membrane.
8-Chloroadenosine (8-Cl-Ado) is a ribonucleoside analogue that is currently in clinical trial for chronic lymphocytic leukemia. Based on the decline in cellular ATP pool following 8-Cl-Ado treatment, we hypothesized that 8-Cl-ADP and 8-Cl-ATP may interfere with ATP synthase, a key enzyme in ATP production. Mitochondrial ATP synthase is composed of two major parts; F(O) intermembrane base and F1 domain, containing alpha and beta subunits. Crystal structures of both alpha and beta subunits that bind to the substrate, ADP, are known in tight binding (alpha(dp)beta(dp)) and loose binding (alpha(tp)beta(tp)) states. Molecular docking demonstrated that 8-Cl-ADP/8-Cl-ATP occupied similar binding modes as ADP/ATP in the tight and loose binding sites of ATP synthase, respectively, suggesting that the chlorinated nucleotide metabolites may be functional substrates and inhibitors of the enzyme. The computational predictions were consistent with our whole cell biochemical results. Oligomycin, an established pharmacological inhibitor of ATP synthase, decreased both ATP and 8-Cl-ATP formation from exogenous substrates, however, did not affect pyrimidine nucleoside analogue triphosphate accumulation. Synthesis of ATP from ADP was inhibited in cells loaded with 8-Cl-ATP. These biochemical studies are in consent with the computational modeling; in the alpha(tp)beta(tp) state 8-Cl-ATP occupies similar binding as ANP, a non-hydrolyzable ATP mimic that is a known inhibitor. Similarly, in the substrate binding site (alpha(dp)beta(dp)) 8-Cl-ATP occupies a similar position as ATP mimic ADP-BeF(3)(-). Collectively, our current work suggests that 8-Cl-ADP may serve as a substrate and the 8-Cl-ATP may be an inhibitor of ATP synthase.
Rituximab improves outcomes for persons with lymphoproliferative disorders and is increasingly used to treat immune-mediated illnesses. Recent reports describe 2 patients with systemic lupus erythematosus and 1 with rheumatoid arthritis who developed progressive multifocal leukoencephalopathy (PML) after rituximab treatment. We reviewed PML case descriptions among patients treated with rituximab from the Food and Drug Administration, the manufacturer, physicians, and a literature review from 1997 to 2008. Overall, 52 patients with lymphoproliferative disorders, 2 patients with systemic lupus erythematosus, 1 patient with rheumatoid arthritis, 1 patient with an idiopathic autoimmune pancytopenia, and 1 patient with immune thrombocytopenia developed PML after treatment with rituximab and other agents. Other treatments included hematopoietic stem cell transplantation (7 patients), purine analogs (26 patients), or alkylating agents (39 patients). One patient with an autoimmune hemolytic anemia developed PML after treatment with corticosteroids and rituximab, and 1 patient with an autoimmune pancytopenia developed PML after treatment with corticosteroids, azathioprine, and rituximab. Median time from last rituximab dose to PML diagnosis was 5.5 months. Median time to death after PML diagnosis was 2.0 months. The case-fatality rate was 90%. Awareness is needed of the potential for PML among rituximab-treated persons.
Glucocorticoids are widely used for the treatment of hematological malignancies; however, their chronic use results in numerous metabolic side effects. Thus, the development of selective glucocorticoid receptor (GR) activators (SEGRA) with improved therapeutic index is important. GR regulates gene expression via (1) transactivation that requires GR homodimer binding to gene promoters and is linked to side effects and (2) transrepression-mediated via negative GR interaction with other transcription factors. Novel GR modulator Compound A (CpdA) prevents GR dimerization, retains glucocorticoid anti-inflammatory activity and has fewer side effects compared with glucocorticoids in vivo. Here we tested CpdA anticancer activity in human T- and B-lymphoma and multiple myeloma cells expressing GR and their counterparts with silenced GR. We found that CpdA in GR-dependent manner strongly inhibited growth and viability of human T-, B-lymphoma and multiple myeloma cells. Furthermore, primary leukemia cell cultures from T-ALL patients appeared to be equally sensitive to glucocorticoid dexamethasone and CpdA. It is known that GR expression is controlled by proteasome. We showed that pretreatment of lymphoma CEM and NCEB cells with proteasome-inhibitor Bortezomib resulted in GR accumulation and enhanced ligand properties of CpdA, shifting GR activity toward transrepression evaluated by inhibition of NF?B and AP-1 transcription factors. We also revealed remarkable GR-dependent cooperation between CpdA and Bortezomib in suppressing growth and survival of T- and B-lymphoma and multiple myeloma MM.1S cells. Overall, our data provide the rationale for novel GR-based therapy for hematological malignancies based on combination of SEGRA with proteasome inhibitors.
The addition of sulfate to glycan structures can regulate their ability to serve as ligands for glycan-binding proteins. Although sulfate groups present on the monosaccharides glucosamine, uronate, N-acetylglucosamine and N-acetylgalactosamine are recognized by defined receptors that mediate important functions, the functional significance of galactose-6-O-sulfate (Gal6S) is not known. However, in vitro studies using synthetic glycans and sulfotransferase overexpression implicate Gal6S as a binding determinant for the lymphocyte homing receptor, L-selectin. Only two sulfotransferases have been shown to generate Gal6S, namely keratan sulfate galactose 6-O-sulfotransferase (KSGal6ST) and chondroitin 6-O-sulfotransferase-1 (C6ST-1). In the present study, we use mice deficient in KSGal6ST and C6ST-1 to test whether Gal6S contributes to ligand recognition by L-selectin in vivo. First, we establish that KSGal6ST is selectively expressed in high endothelial venules (HEVs) in lymph nodes and Peyers patches. We also determine by mass spectrometry that KSGal6ST generates Gal6S on several classes of O-glycans in peripheral lymph nodes. Furthermore, KSGal6ST, but not C6ST-1, is required for the generation of the Gal6S-containing glycan, 6,6-disulfo-3sLN (Sia?2?3[6S]Gal?1?4[6S]GlcNAc) or a closely related structure in lymph node HEVs. Nevertheless, L-selectin-dependent short-term homing of lymphocytes is normal in KSGal6ST-deficient mice, indicating that the Gal6S-containing structures we detected do not contribute to L-selectin ligand recognition in this setting. These results refine our understanding of the biological ligands for L-selectin and introduce a mouse model for investigating the functions of Gal6S in other contexts.
Oesophageal cancer is the eighth most commonly diagnosed cancer worldwide, and there is a need for biomarkers to improve diagnosis, prognosis and treatment. Sulfatases 2 (SULF2) is an extracellular endosulphatase that regulates several signalling pathways in carcinogenesis and has been associated with poor prognosis. This study evaluates the relationship between SULF2 expression by immunohistochemistry and overall survival in patients with oesophageal cancer.
Epithelial-mesenchymal transition (EMT) has been associated with metastatic spread and EGF receptor (EGFR) inhibitor resistance. We developed and validated a robust 76-gene EMT signature using gene expression profiles from four platforms using non-small cell lung carcinoma (NSCLC) cell lines and patients treated in the Biomarker-Integrated Approaches of Targeted Therapy for Lung Cancer Elimination (BATTLE) study.
The Prometra® Programmable Pump System (Flowonix Medical, Inc., Mt. Olive, NJ, USA) is designed for continuous intrathecal administration of morphine sulfate to treat chronic intractable pain. As a follow-up to a previous report on acute six-month data, this study evaluated the efficacy of treatment at one year and the accuracy of drug delivery throughout the study (average of 2.5 years, range 0-3.6 years).
8-Amino-adenosine (8-NH(2)-Ado) is a ribose sugar nucleoside analogue that reduces cellular ATP levels and inhibits mRNA synthesis. Estrogen receptor-negative (ER-) metastatic breast cancers often contain mutant p53; therefore, we asked if 8-NH(2)-Ado could kill breast cancer cells without activating the p53-pathway. Regardless of the breast cancer subtype tested or the p53 status of the cells, 8-NH(2)-Ado was more cytotoxic than either gemcitabine or etoposide. 8-NH(2)-Ado treatment inhibited cell proliferation, activated cell death, and did not activate transcription of the p53 target gene p21 or increase protein levels of either p53 or p21. This occurred in the estrogen receptor-positive (ER+) MCF-7 cells that express wild-type p53, the ER+ T47-D cells that express mutant p53, and the ER- MDA-MB-468 cells or MDA-MB-231 cells that both express mutant p53. 8-NH(2)-Ado induced apoptotic death of MCF-7 cells and apoptosis was not inhibited by knockdown of functional p53. Moreover, the pan-caspase inhibitor Z-VAD blocked the 8-NH(2)-Ado-induced MCF-7 cell death. Interestingly, 8-NH(2)-Ado caused the MDA-MB-231 cells to detach from the plate with only limited evidence of apoptotic cell death markers and the cell death was not inhibited by Z-VAD. Inhibition of MDA-MB-231 cell autophagy, by reduction of ATG7 or 3-methyladenine treatment, did not block this 8-NH(2)-Ado-mediated cytotoxicity. Importantly 8-NH(2)-Ado was highly cytotoxic to triple-negative breast cancer cells and worked through a pathway that did not require wild-type p53 for cytoxicity. Therefore, 8-NH(2)-Ado should be considered for the treatment of triple-negative breast cancers that are chemotherapy resistant.
Blood-borne lymphocytes home to lymph nodes by interacting with and crossing high endothelial venules (HEVs). The transendothelial migration (TEM) step is poorly understood. Autotaxin (ATX) is an ectoenzyme that catalyzes the conversion of lysophosphatidylcholine (LPC) to lysophosphatidic acid (LPA), a bioactive lipid and a close relative of sphingosine 1-phosphate. HEVs produce and secrete ATX into the blood. A prior study implicated ATX in the overall homing process, but the step in which it functions and its mechanism of action have not been defined. In this article, we show that HA130, an inhibitor of the enzymatic activity of ATX, slows T cell migration across lymph node HEVs in vivo. Ex vivo, ATX plus LPC or LPA itself induces the polarization of mouse naive T cells and stimulates their motility on an ICAM-1 substratum. Under physiologic shear conditions in a flow chamber, LPA or ATX/LPC strongly enhances TEM of integrin-arrested T cells across an endothelial monolayer. HA130 blunts the TEM-promoting activity of ATX, paralleling its in vivo effects. T cells possess Mn(+2)-activatable receptors for ATX, which are localized at the leading edge of polarized cells. ATX must bind to these receptors to elicit a maximal TEM response, providing a mechanism to focus the action of LPA onto arrested lymphocytes in flowing blood. Our results indicate that LPA produced via ATX facilitates T cell entry into lymph nodes by stimulating TEM, substantiating an additional step in the homing cascade. This entry role for LPA complements the efflux function of sphingosine 1-phosphate.
Transformed cells exhibit a high rate of glucose consumption beyond that necessary for ATP synthesis. Glucose aids in the generation of biomass and regulates cellular signaling critical for oncogenic progression. A key rate-limiting step in glucose utilization is the transport of glucose across the plasma membrane. This review will highlight key glucose transporters (GLUTs) and current therapies targeting this class of proteins.
The nucleoside analogues 8-amino-adenosine and 8-chloro-adenosine have been investigated in the context of B-lineage lymphoid malignancies by our laboratories due to the selective cytotoxicity they exhibit toward multiple myeloma (MM), chronic lymphocytic leukemia (CLL), and mantle cell lymphoma (MCL) cell lines and primary cells. Encouraging pharmacokinetic and pharmacodynamic properties of 8-chloro-adenosine being documented in an ongoing Phase I trial in CLL provide additional impetus for the study of these promising drugs. In order to foster a deeper understanding of the commonalities between their mechanisms of action and gain insight into specific patient cohorts positioned to achieve maximal benefit from treatment, we devised a novel two-tiered chemoinformatic screen to identify molecular determinants of responsiveness to these compounds. This screen entailed: 1) the elucidation of gene expression patterns highly associated with the anti-tumor activity of 8-chloro-adenosine in the NCI-60 cell line panel, 2) characterization of altered transcript abundances between paired MM and MCL cell lines exhibiting differential susceptibility to 8-amino-adenosine, and 3) integration of the resulting datasets. This approach generated a signature of seven unique genes including G6PD which encodes the rate-determining enzyme of the pentose phosphate pathway (PPP), glucose-6-phosphate dehydrogenase. Bioinformatic analysis of primary cell gene expression data demonstrated that G6PD is frequently overexpressed in MM and CLL, highlighting the potential clinical implications of this finding. Utilizing the paired sensitive and resistant MM and MCL cell lines as a model system, we go on to demonstrate through loss-of-function and gain-of-function studies that elevated G6PD expression is necessary to maintain resistance to 8-amino- and 8-chloro-adenosine but insufficient to induce de novo resistance in sensitive cells. Taken together, these results indicate that G6PD activity antagonizes the cytotoxicity of 8-substituted adenosine analogues and suggests that administration of these agents to patients with B-cell malignancies exhibiting normal levels of G6PD expression may be particularly efficacious.
Cutaneous T-cell lymphoma (CTCL) is a radiosensitive tumor. Presently, treatment with radiation is given in multiple fractions. The current literature lacks data that support single-fraction treatment for CTCL. This retrospective review assesses the clinical response in patients treated with a single fraction of radiation.
Multiple myeloma is one of numerous malignancies characterized by increased glucose consumption, a phenomenon with significant prognostic implications in this disease. Few studies have focused on elucidating the molecular underpinnings of glucose transporter (GLUT) activation in cancer, knowledge that could facilitate identification of promising therapeutic targets. To address this issue, we performed gene expression profiling studies involving myeloma cell lines and primary cells as well as normal lymphocytes to uncover deregulated GLUT family members in myeloma. Our data demonstrate that myeloma cells exhibit reliance on constitutively cell surface-localized GLUT4 for basal glucose consumption, maintenance of Mcl-1 expression, growth, and survival. We also establish that the activities of the enigmatic transporters GLUT8 and GLUT11 are required for proliferation and viability in myeloma, albeit because of functionalities probably distinct from whole-cell glucose supply. As proof of principle regarding the therapeutic potential of GLUT-targeted compounds, we include evidence of the antimyeloma effects elicited against both cell lines and primary cells by the FDA-approved HIV protease inhibitor ritonavir, which exerts a selective off-target inhibitory effect on GLUT4. Our work reveals critical roles for novel GLUT family members and highlights a therapeutic strategy entailing selective GLUT inhibition to specifically target aberrant glucose metabolism in cancer.
Treatment regimens of patients with CTCL vary widely based on clinician preference and patient tolerance. Skin directed therapies are recommended for patients with early stage IA and IB MF, with combinations used in refractory cases. While no regimen has been proven to prolong survival in advanced stages, immunomodulatory regimens should be used initially to reduce the need for cytotoxic therapies. In more advanced stages of disease, treatment efforts should strive for palliation and improvement of quality of life. With many new therapies and strategies on the horizon, the future looks promising for CTCL patients. Unfortunately, other than allogeneic HCT, there are no potential curative therapies for CTCL. Clinical trials are currently underway to identify new therapies to improve quality of life for patients, and researchers are hard at work to identify novel pathways and genes for prognostication and as targets for therapies. Importantly, collaborative clinical trials to enhance rates of accrual need to be conducted, and improved interpretation of data via standardizing end points and response criteria should be an emphasis. Recently, the International Society for Cutaneous Lymphomas (ISCL), the United States Cutaneous Lymphoma Consortium (USCLC), and the Cutaneous Lymphoma Task Force of the European Organisation for Research and Treatment of Cancer (EORTC) met to develop consensus guidelines to facilitate collaboration on clinical trials. These proposed guidelines consist of: recommendations for standardizing general protocol design; a scoring system for assessing tumor burden in skin, lymph nodes, blood, and viscera; definition of response in skin, nodes, blood, and viscera; a composite global response score; and a definition of end points. Although these guidelines were generated by consensus panels, they have not been prospectively or retrospectively validated through analysis of large patient cohorts.
Glioblastoma (GBM), a uniformly lethal brain cancer, is characterized by diffuse invasion and abnormal activation of multiple receptor tyrosine kinase (RTK) signaling pathways, presenting a major challenge to effective therapy. The activation of many RTK pathways is regulated by extracellular heparan sulfate proteoglycans (HSPG), suggesting these molecules may be effective targets in the tumor microenvironment. In this study, we demonstrated that the extracellular sulfatase, SULF2, an enzyme that regulates multiple HSPG-dependent RTK signaling pathways, was expressed in primary human GBM tumors and cell lines. Knockdown of SULF2 in human GBM cell lines and generation of gliomas from Sulf2(-/-) tumorigenic neurospheres resulted in decreased growth in vivo in mice. We found a striking SULF2 dependence in activity of PDGFR?, a major signaling pathway in GBM. Ablation of SULF2 resulted in decreased PDGFR? phosphorylation and decreased downstream MAPK signaling activity. Interestingly, in a survey of SULF2 levels in different subtypes of GBM, the proneural subtype, characterized by aberrations in PDGFR?, demonstrated the strongest SULF2 expression. Therefore, in addition to its potential as an upstream target for therapy of GBM, SULF2 may help identify a subset of GBMs that are more dependent on exogenous growth factor-mediated signaling. Our results suggest the bioavailability of growth factors from the microenvironment is a significant contributor to tumor growth in a major subset of human GBM.
Abstract Over the past decade, there has been increasing biochemical evidence that the Janus kinase (JAK)-signal transducer and activator of transcription (STAT) pathway is aberrantly activated in malignant cells from patients with a wide spectrum of cancers of the blood and immune systems. The emerging availability of small molecule inhibitors of JAK kinases and other signaling molecules in the JAK-STAT pathway has allowed preclinical studies validating an important role of this pathway in the pathogenesis of many hematologic malignancies, and provided motivation for new strategies for treatment of these diseases. Here, a roundtable panel of experts reviews the current preclinical and clinical landscape of the JAK-STAT pathway in acute lymphoid and myeloid leukemias, lymphomas and myeloma, and chronic myeloid neoplasms.
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