20-Hydroxyeicosatetraenoic acid (20-HETE), Cyp4a-derived eicosanoid, is a lipid mediator that promotes tumor growth, as well as causing detrimental effects in cerebral circulation. We determined whether concurrent inhibition of cyclooxygenase-2 (COX-2) and 20-HETE affects colon tumor growth and ischemic stroke outcomes. The expression of Cyp4a and COXs and production of 20-HETE and PGE2 were determined in murine colon carcinoma (MC38) cells. We then examined the effects of combined treatment with rofecoxib, a potent COX-2 inhibitor, and HET0016, a potent Cyp4a inhibitor, on the growth and proliferation of MC38 cells. Subsequently, we tested the effects of HET0016 plus rofecoxib in MC38 tumor and ischemic stroke models. Cyp4a and COXs are highly expressed in MC38 cells. Respectively, HET0016 and rofecoxib inhibited 20-HETE and PGE2 formation in MC38 cells. Moreover, rofecoxib combined with HET0016 had greater inhibitory effects on the growth and proliferation of MC38 cells than did rofecoxib alone. Importantly, rofecoxib combined with HET0016 provided greater inhibition on tumor growth than did rofecoxib alone in MC38 tumor-bearing mice. Prolonged treatment with rofecoxib selectively induced circulating 20-HETE levels and caused cerebrovascular damage after ischemic stroke, whereas therapy with rofecoxib and HET0016 attenuated 20-HETE levels and reduced rofecoxib-induced cerebrovascular damage and stroke outcomes during anti-tumor therapy. Thus these results demonstrate that combination therapy with rofecoxib and HET0016 provides a new treatment of colon tumor, which can not only enhance the anti-tumor efficacy of rofecoxib, but also reduce rofecoxib-induced cerebrovascular damage and stroke outcomes.
In traditional Chinese medicine, Nitraria sibirica Pall. (Nitrariaceae) is used to treat hypertension. This study determined the effects of the total alkaloids of the leaves of Nitraria sibirica (NSTA) on blood pressure and albuminuria in mice treated with angiotensin II and a high-salt diet (ANG/HS). Adult mice were divided into three groups: control; infused with angiotensin II and fed a diet containing 4% NaCl (ANG/HS; and ANG/HS plus injection of NSTA (1 mg·kg(-1)·d(-1), i.p.). After treatment of these regimens, daily water and food intake, kidney weight, blood pressure, urinary albumin excretion, renal concentrations of inflammatory markers, including soluble intercellular adhesion molecule-1 (sICAM-1) and monocyte chemoattractant protein-1 (MCP-1), and the expression of renal fibrosis markers were determined. Compared to the control group, the ANG/HS group had higher blood pressure and urinary albumin excretion. Treatment with NSTA in ANG/HS mice for three weeks significantly reduced blood pressure and urinary albumin excretion. ANG/HS treatment caused elevated levels of sICAM-1 and MCP-1, as well as increased fibrosis markers. Concurrent treatment with ANG/HS and NSTA attenuated the levels and expression of renal inflammatory and fibrosis markers. Treatment with NSTA effectively reduces hypertension-induced albuminuria through the reduction of renal inflammatory and fibrosis markers.
Primary central nervous system (CNS) atypical teratoid/rhabdoid tumor (ATRT) is an extremely malignant pediatric brain tumor observed in infancy and childhood. It has been reported that a subpopulation of CD133(+) cells isolated from ATRT tumors present with cancer stem-like and radioresistant properties. However, the exact biomolecular mechanisms of ATRT or CD133-positive ATRT (ATRT-CD133(+)) cells are still unclear. We have previously shown that ATRT-CD133(+) cells have pluripotent differentiation ability and the capability of malignant cells to be highly resistant to ionizing radiation (IR). By using microRNA array and quantitative RT-PCR in this study, we showed that expression of miR142-3p was lower in ATRT-CD133(+) cells than in ATRT-CD133(-) cells. miR142-3p overexpression significantly inhibited the self-renewal and tumorigenicity of ATRT-CD133(+) cells. On the contrary, silencing of endogenous miR142-3p dramatically increased the tumor-initiating and stem-like cell capacities in ATRT cells or ATRT-CD133(-) cells and further promoted the mesenchymal transitional and radioresistant properties of ATRT cells. Most importantly, therapeutic delivery of miR142-3p in ATRT cells effectively reduced its lethality by blocking tumor growth, repressing invasiveness, increasing radiosensitivity, and prolonging survival time in orthotropic-transplanted immunocompromised mice. These results demonstrate the prospect of developing novel miRNA-based strategies to block the stem-like and radioresistant properties of malignant pediatric brain cancer stem cells.
Inhibition of soluble epoxide hydrolase (Ephx2) has been shown to play a protective role in cardiac hypertrophy, but the mechanism is not fully understood. We tested the hypothesis that deletion of soluble epoxide hydrolase attenuates cardiac hypertrophy via down-regulation of cardiac fibroblasts-derived fibroblast growth factor-2.
Inner medulla collecting duct (IMCD) cells are the key part for urinary concentration. Hypotonic stress may trigger apoptosis of IMCD cells and induce renal injury. Epoxyeicosatrienoic acids (EETs) play an important role in anti-apoptosis, but their roles in hypotonic-induced apoptosis of IMCD cells are still unclear. Here we found increasing exogenous 11, 12-EET or endogenous EETs with Ad-CMV-CYP2C23-EGFP transfection decreased apoptosis of IMCD cells induced by hypotonic stress. Moreover, up-regulation of ?-ENaC induced by hypotonic stress was abolished by elevation of exogenous or endogenous EETs. Collectively, this study illustrated that EETs attenuated hypotonic-induced apoptosis of IMCD cells, and that regulation of ?-ENAC may be a possible mechanism contributing to the anti-apoptotic effect of EETs in response to hypotonic stress.
Epigenetic regulation plays a critical role in glioblastoma (GBM) tumorigenesis. However, how microRNAs (miRNAs) and cytokines cooperate to regulate GBM tumor progression is still unclear. Here, we show that interleukin-6 (IL-6) inhibits miR142-3p expression and promotes GBM propagation by inducing DNA methyltransferase 1-mediated hypermethylation of the miR142-3p promoter. Interestingly, miR142-3p also suppresses IL-6 secretion by targeting the 3 UTR of IL-6. In addition, miR142-3p also targets the 3 UTR and suppresses the expression of high-mobility group AT-hook 2 (HMGA2), leading to inhibition of Sox2-related stemness. We further show that HMGA2 enhances Sox2 expression by directly binding to the Sox2 promoter. Clinically, GBM patients whose tumors present upregulated IL-6, HMGA2, and Sox2 protein expressions and hypermethylated miR142-3p promoter also demonstrate poor survival outcome. Orthotopic delivery of miR142-3p blocks IL-6/HMGA2/Sox2 expression and suppresses stem-like properties in GBM-xenotransplanted mice. Collectively, we discovered an IL-6/miR142-3p feedback-loop-dependent regulation of GBM malignancy that could be a potential therapeutic target.
Epidermal growth factor receptor (EGFR) is a membrane-bound receptor tyrosine kinase, which can transduce intracellular signals responsible for cell proliferation. It is frequently overexpressed and/or constitutively activated in non-small cell lung cancer and thus is considered as a major cause of this disease. Recently, EGFR has been found in the nucleus where the nuclear EGFR (nEGFR) can function as a transcription factor activating the transcription of genes such as cyclin D1 gene (CCND1), which is essential for cell proliferation. Nevertheless, how nEGFRs transcriptional activity is regulated remains unclear. Promyelocytic leukemia protein (PML) is a tumor suppressor, which is lost in various cancers including lung cancer. However, the role of PML in the suppression of lung cancer growth is still unclear. When we investigated the role of PML in the regulation of lung cancer cell growth, we found that PML isoform IV (PMLIV) preferentially represses the growth of lung cancer cells bearing constitutively active EGFR. Besides, when growing in the EGFR activating conditions, the growth of EGFR wild-type bearing A549 cells has been repressed by PMLIV overexpression. We also found that PMLIV can interact physically with nEGFR and represses the transcription of nEGFR target genes. We showed that PMLIV is recruited by nEGFR to the target promoters and reduces the promoter histone acetylation level via HDAC1. Together, our results suggest that PMLIV interacts with nEGFR upon EGFR activation and represses the transcription of nEGFR target genes such as CCND1 and thus leading to inhibition of the lung cancer cell growth.
ALDH1(+)CD44(+) cells are putative tumor-initiating cells (TIC) in head and neck squamous cell carcinomas (HNC). miR-145 regulates tumorigenicity in various cancers but the breadth of its mechanistic contributions and potential therapeutic applications are not completely known. Here, we report that ALDH1(+)CD44(+)-HNC cells express reduced levels of miR145. SPONGE-mediated inhibition of miR-145 (Spg-miR145) was sufficient to drive tumor-initiating characteristics in non-TICs/ALDH1(-)CD44-negative HNC cells. Mechanistic analyses identified SOX9 and ADAM17 as two novel miR145 targets relevant to this process. miR-145 expression repressed TICs in HNC in a manner associated with SOX9 interaction with the ADAM17 promoter, thereby activating ADAM17 expression. Notably, the SOX9/ADAM17 axis dominated the TIC-inducing activity of miR-145. Either miR-145 suppression or ADAM17 overexpression in non-TICs/ALDH1(-)CD44(-)-HNC cells increased expression and secretion of interleukin (IL)-6 and soluble-IL-6 receptor (sIL-6R). Conversely, conditioned medium from Spg-miR145-transfected non-TICs/ALDH1(-)CD44(-)-HNC cells was sufficient to confer tumor-initiating properties in non-TICs/ALDH1(-)CD44(-)-HNC and this effect could be abrogated by an IL-6-neutralizing antibody. We found that curcumin administration increased miR-145 promoter activity, thereby decreasing SOX9/ADAM17 expression and eliminating TICs in HNC cell populations. Delivery of lentivral-miR145 or orally administered curcumin blocked tumor progression in HNC-TICs in murine xenotransplant assays. Finally, immunohistochemical analyses of patient specimens confirmed that an miR-145(low)/SOX9(high)/ADAM17(high) phenotype correlated with poor survival. Collectively, our results show how miR-145 targets the SOX9/ADAM17 axis to regulate TIC properties in HNC, and how altering this pathway may partly explain the anticancer effects of curcumin. By inhibiting IL-6 and sIL-6R as downstream effector cytokines in this pathway, miR-145 seems to suppress a paracrine signaling pathway in the tumor microenvironment that is vital to maintain TICs in HNC.
The involvement of stemness factors in cancer initiation and progression has drawn much attention recently, especially after the finding that introducing four stemness factors in somatic cells is able to reprogram the cells back to an embryonic stem cell-like state. Following accumulating data revealing abnormal elevated expression levels of key stemness factors, like Nanog, Oct4, and Sox2, in several types of cancer stem cells; the importance and therapeutic potential of targeting these stemness regulators in cancers has turned to research focus. Nanog determines cell fate in both embryonic and cancer stem cells; activating Nanog at an inappropriate time would result in cancer stem cells rather than normal pluripotent stem cells or differentiated somatic cells. Upregulated Nanog is correlated with poor survival outcome of patients with various types of cancer. The discoveries of downstream regulatory pathways directly or indirectly mediated by Nanog indicate that Nanog regulates several aspects of cancer development such as tumor cell proliferation, self-renewal, motility, epithelial-mesenchymal transition, immune evasion, and drug-resistance, which are all defined features for cancer stem cells. The current review paper illustrates the central role of Nanog in the regulatory networks of cancer malignant development and stemness acquirement, as well as in the communication between cancer cells and the surrounding stroma. Though a more defined model is needed to test the therapeutic efficacy of targeting Nanog as a cancer treatment method, current animal experiments using siNanog or shNanog have shown the promising therapeutic potential of Nanog targeting in several types of cancer.
Glioblastomas (GBMs) are the most common primary brain tumors with poor prognosis. CD133 has been considered a putative marker of cancer stem cells (CSCs) in malignant cancers, including GBMs. MicroRNAs (miRNAs), highly conserved small RNA molecules, may target oncogenes and have potential as a therapeutic strategy against cancer. However, the role of miRNAs in GBM-associated CSCs remains mostly unclear. In this study, our miRNA/mRNA-microarray and RT-PCR analysis showed that the expression of miR145 (a tumor-suppressive miRNA) is inversely correlated with the levels of Oct4 and Sox2 in GBM-CD133(+) cells and malignant glioma specimens. We demonstrated that miR145 negatively regulates GBM tumorigenesis by targeting Oct4 and Sox2 in GBM-CD133(+). Using polyurethane-short branch polyethylenimine (PU-PEI) as a therapeutic-delivery vehicle, PU-PEI-mediated miR145 delivery to GBM-CD133(+) significantly inhibited their tumorigenic and CSC-like abilities and facilitated their differentiation into CD133(-)-non-CSCs. Furthermore, PU-PEI-miR145-treated GBM-CD133(+) effectively suppressed the expression of drug-resistance and anti-apoptotic genes and increased the sensitivity of the cells to radiation and temozolomide. Finally, the in vivo delivery of PU-PEI-miR145 alone significantly suppressed tumorigenesis with stemness, and synergistically improved the survival rate when used in combination with radiotherapy and temozolomide in orthotopic GBM-CD133(+)-transplanted immunocompromised mice. Therefore, PU-PEI-miR145 is a novel therapeutic approach for malignant brain tumors.
Studies suggest that soluble epoxide hydrolase (sEH) inhibition reduces end-organ damage in cardiovascular diseases. We hypothesize that sEH gene (Ephx2) knockout (KO) improves endothelial function and reduces renal injury in streptozotocin-induced diabetes. After 6 wk of diabetes, afferent arteriolar relaxation to acetylcholine was impaired in diabetic wild-type (WT) mice, as the maximum relaxation was 72% of baseline diameter in the WT but only 31% in the diabetic mice. Ephx2 KO improved afferent arteriolar relaxation to acetylcholine in diabetes as maximum relaxation was 58%. Urinary monocyte chemoattractant protein-1 (MCP-1) excretion significantly increased in diabetic WT mice compared with control (868 ± 195 vs. 31.5 ± 7 pg/day), and this increase was attenuated in diabetic Ephx2 KO mice (420 ± 98 pg/day). The renal phospho-IKK-to-IKK ratio and nuclear factor-?B were significantly decreased, and hemeoxygenase-1 (HO-1) expression increased in diabetic Ephx2 KO compared with diabetic WT mice. Renal NADPH oxidase and urinary thiobarbituric acid reactive substances excretion were reduced in diabetic Ephx2 KO compared with diabetic WT mice. Albuminuria was also elevated in diabetic WT mice compared with control (170 ± 43 vs. 37 ± 13 ?g/day), and Ephx2 KO reduced this elevation (50 ± 15 ?g/day). Inhibition of sEH using trans-4-[4-(3-adamantan-1-yl-ureido)-cyclohexyloxy]-benzoic acid (tAUCB) also reduced renal inflammation and injury in diabetic WT mice. Furthermore, inhibition of HO with stannous mesoporphyrin negated the reno-protective effects of tAUCB or Ephx2 KO during diabetes. These data demonstrate that Ephx2 KO improves endothelial function and reduces renal injury during diabetes. Additionally, our data also suggest that activation of HO-1 contributes to improved renal injury in diabetic Ephx2 KO mice.
Despite intensive investigation, how DNA methylation influences endothelial function remains poorly understood. We used methyl-CpG-binding domain protein 2 (MBD2), an interpreter for DNA methylome-encoded information, to dissect the impact of DNA methylation on endothelial function in both physiological and pathophysiological states.
Arachidonic acid (AA) is metabolized by cyclooxygenase (COX), lipoxygenase (LOX), and cytochrome P450 (CYP) enzymes into eicosanoids, which are involved in diverse diseases, including type 1 and type 2 diabetes. During the last 30 years, evidence has been accumulated that suggests important functions for eicosanoids in the control of pancreatic ?-cell function and destruction. AA metabolites of the COX pathway, especially prostaglandin E(2) (PGE(2)), appear to be significant factors to ?-cell dysfunction and destruction, participating in the pathogenesis of diabetes and its complications. Several elegant studies have contributed to the sorting out of the importance of 12-LOX eicosanoids in cytokine-mediated inflammation in pancreatic ? cells. The role of CYP eicosanoids in diabetes is yet to be explored. A recent publication has demonstrated that stabilizing the levels of epoxyeicosatrienoic acids (EETs), CYP eicosanoids, by inhibiting or deleting soluble epoxide hydrolase (sEH) improves ?-cell function and reduces ?-cell apoptosis in diabetes. In this review we summarize recent findings implicating these eicosanoid pathways in diabetes and its complications. We also discuss the development of animal models with targeted gene deletion and specific enzymatic inhibitors in each pathway to identify potential targets for the treatment of diabetes and its complications.
Though aldosterone-renin ratio (ARR) is the current routine screening method for suspicious primary aldosteronism, we hypothesized that the simple formula combining body mass index (BMI) and serum potassium to urine potassium clearance (PUKC) ratio was comparable to ARR.
Induced pluripotent stem cells (iPSCs) with four reprogramming factors (Oct-4/Sox2/Klf-4/c-Myc) have been shown to differentiate into hepatic lineages. However, it was unclear whether obviation of the c-Myc oncogene in iPSCs affected hepatic differentiation or inhibited in vivo tumor formation. In this study, we demonstrated that iPSCs without c-Myc had the capacity to differentiate into hepatocyte-like cells (iPSC-Heps) with biological functions. As detected using planar-radionuclide imaging and Hoechst labeling assays, these iPSCs and iPSC-Heps tended to mobilize to the injured liver area in thioacetamide (TAA)-treated mice. Intravenous transplantation of both iPSCs and iPSC-Heps but not mouse embryonic fibroblasts (MEFs) reduced the hepatic necrotic area, improved liver functions, and rescued TAA-treated mice from lethal acute hepatic failure (AHF). In addition, microarray-based bioinformatics and quantitative RT-PCR showed high expression of antioxidant genes in iPSCs and iPSC-Heps compared to MEFs. In vivo and in vitro studies of NAC pretreatment confirmed that iPSCs and iPSC-Heps potentially suppressed ROS production and activated antioxidant enzymes in TAA-injured livers. Six months after transplantation in TAA-treated mice, tumor formation was not seen in non-c-Myc iPSC grafts. Therefore, reprogramming adult somatic cells without c-Myc may prevent oxidative stress-induced damage and provide a safer alternative for hepatic regeneration in AHF.
Epithelial-mesenchymal transition (EMT), a critical process of cancer invasion and metastasis, is associated with stemness property of cancer cells. Though Oct4 and Nanog are homebox transcription factors essential to the self-renewal of stem cells and are expressed in several cancers, the role of Oct4/Nanog signaling in tumorigenesis is still elusive. Here microarray and quantitative real-time PCR analysis showed a parallel, elevated expression of Oct4 and Nanog in lung adenocarcinoma (LAC). Ectopic expressions of Oct4 and Nanog in LACs increased the percentage of CD133-expressing subpopulation and sphere formation, enhanced drug resistance, and promoted EMT. Ectopic expressions of Oct4 and Nanog activated Slug and enhanced the tumor-initiating capability of LAC. Furthermore, double knockdown of Oct4 and Nanog suppressed the expression of Slug, reversed the EMT process, blocked the tumorigenic and metastatic ability, and greatly improved the mean survival time of transplanted immunocompromised mice. The immunohistochemical analysis demonstrated that expressions of Oct4, Nanog, and Slug were present in high-grade LAC, and triple positivity of Oct4/Nanog/Slug indicated a worse prognostic value of LAC patients. Our results support the notion that the Oct4/Nanog signaling controls epithelial-mesenchymal transdifferentiation, regulates tumor-initiating ability, and promotes metastasis of LAC.
Soluble epoxide hydrolase (sEH) is an enzyme involved in the metabolism of endogenous inflammatory and antiapoptotic mediators. However, the roles of sEH in diabetes and the pancreas are unknown. Our aims were to determine whether sEH is involved in the regulation of hyperglycemia in diabetic mice and to investigate the reasons for the regulation of insulin secretion by sEH deletion or inhibition in islets. We used two separate approaches, targeted disruption of Ephx2 gene [sEH knockout (KO)] and a selective inhibitor of sEH [trans-4-[4-(3-adamantan-1-ylureido)-cyclohexyloxy]-benzoic acid (t-AUCB)], to assess the role of sEH in glucose and insulin homeostasis in streptozotocin (STZ) mice. We also examined the effects of sEH KO or t-AUCB on glucose-stimulated insulin secretion (GSIS) and intracellular calcium levels in islets. Hyperglycemia in STZ mice was prevented by both sEH KO and t-AUCB. In addition, STZ mice with sEH KO had improved glucose tolerance. More important, when insulin levels were assessed by hyperglycemic clamp study, sEH KO was found to promote insulin secretion. In addition, sEH KO and t-AUCB treatment augmented islet GSIS. Islets with sEH KO had a greater intracellular calcium influx when challenged with high glucose or KCl in the presence of diazoxide. Moreover, sEH KO reduced islet cell apoptosis in STZ mice. These results show not only that sEH KO and its inhibition prevent hyperglycemia in diabetes, but also that sEH KO enhances islet GSIS through the amplifying pathway and decreases islet cell apoptosis in diabetes.
PGE(2) has an established role in renal water handling. The present study was undertaken to examine the role of microsomal prostaglandin E synthase-1 (mPGES-1) in the diuretic response to acute and chronic water loading. Compared with wild-type (+/+) controls, mPGES-1 -/- mice exhibited impaired ability to excrete an acute, but not chronic water load. In response to acute water loading, urinary PGE(2) excretion in the +/+ mice increased at 2 h, in parallel with increased urine flow. In contrast, the -/- mice exhibited a delayed increase in urinary PGE(2) excretion, coinciding with the stimulation of renal medullary mRNA expression of cytosolic prostaglandin E synthase but not mPGES-2. At baseline, renal aquaporin-2 (AQP2) expression in mPGES-1 -/- mice was enhanced compared with the +/+ control. In response to acute water loading, renal AQP2 expression in the +/+ mice was significantly reduced, and this reduction was blunted in the -/- mice. Despite striking changes in AQP2 protein expression, renal AQP2 mRNA in both genotypes largely remained unchanged. Overall, these data support an important role of mPGES-1 in provoking the diuretic response to acute water loading.
Type 2 diabetes and dyslipidemia oftentimes present in combination. However, the relative roles of diabetes and diet-induced dyslipidemia in mediating changes in vascular structure, mechanics, and function are poorly understood. Our hypothesis was that addition of a high-fat diet would exacerbate small artery remodeling, compliance, and vascular dysfunction in type 2 diabetes. Vascular remodeling indices [media/lumen (M/L) ratio, collagen abundance and turnover, and matrix metalloproteinase dynamics], mechanical properties (vessel stiffness), and reactivity to pressure and vasoactive factors were measured in third-order mesenteric arteries in control Wistar and type 2 diabetic Goto-Kakizaki (GK) rats fed either a regular or high-fat diet. M/L ratios, total collagen, and myogenic tone were increased in diabetes. Addition of the high-fat diet altered collagen patterns (mature versus new collagen) in favor of matrix accumulation. Addition of a high-fat diet caused increased constriction to endothelin-1 (0.1-100 nM), showed impaired vasorelaxation to both acetylcholine (0.1 nM-1 microM) and sodium nitroprusside (0.1 nM-1 microM), and increased cardiovascular risk factors in diabetes. These results suggest that moderate elevations in blood glucose, as seen in our lean GK model of type 2 diabetes, promote resistance artery remodeling resulting in increased medial thickness, whereas addition of a high-fat diet contributes to diabetic vascular disease predominantly by impairing vascular reactivity in the time frame used for this study. Although differential in their vascular effects, both hyperglycemia and diet-induced dyslipidemia need to be targeted for effective prevention and treatment of diabetic vascular disease.
The early stage of diabetic nephropathy (DN) is linked to proteinuria. Transforming growth factor (TGF)-beta1 increases glomerular permeability to albumin (P(alb)), whereas 20-HETE and EETs reduce P(alb). To investigate the impact of hyperglycemia and hyperlipidemia on 20-HETE, EETs, and TGF-beta1 in the glomeruli, rats were divided into four groups: ND rats were fed a normal diet, HF rats were fed a high-fat diet, STZ rats were treated with 35 mg/kg of streptozotocin, and HF/STZ rats were fed a HF diet and treated with STZ. After 10 wk on these regimens, blood glucose, urinary albumin, serum cholesterol, serum triglyceride levels, and the kidney-to-body weight ratio were significantly elevated in STZ and HF/STZ rats compared with HF and ND rats. STZ and HF/STZ rats had histopathologic changes and abnormal renal hemodynamics. Expression of glomerular CYP4A, enzymes for 20-HETE production, was significantly decreased in STZ rats, whereas expression of glomerular CYP2C and CYP2J, enzymes for EETs production, was significantly decreased in both STZ and HF/STZ rats. Moreover, glomerular TGF-beta1 levels were significantly greater in STZ and HF/STZ rats than in HF and ND rats. Five-week treatment of STZ rats with clofibrate induced glomerular CYP4A expression and 20-HETE production, but reduced glomerular TGF-beta1 and urinary protein excretion. These results demonstrate that hyperglycemia increases TGF-beta1 but decreases 20-HETE and EETs production in the glomeruli, changes that may be important in causing glomerular damage in the early stage of DN.
Soluble epoxide hydrolase (sEH) is an enzyme involved in the metabolism of endogenous inflammatory and anti-apoptotic mediators. In the present study, we determined the effects of the inhibition of sEH on glucose homeostasis and islet damage in mice treated with streptozotocin (STZ), a model of chemical-induced diabetes. STZ increased daily water intake and decreased visceral (spleen and pancreas) weight in mice; sEH inhibition in STZ mice decreased water intake, but did not affect visceral weight. Hyperglycemia induced by STZ treatment in mice was attenuated by inhibiting sEH. The beneficial effects of sEH inhibition were accompanied, after 2 and 4 weeks of initial administration, by improving glucose tolerance. In contrast, sEH inhibition did not affect insulin tolerance. Using LC/MS analysis, neither STZ nor STZ plus sEH inhibition affected pancreatic and plasma ratios of epoxyeicosatrienoic acids (EETs) to dihydroxyeicosatrienoic acids (DHETs), an index of EETs levels. Western blot analysis showed that mouse cytochrome P450 (CYP) 2C enzymes are the major epoxygenases in islets. On day 5 after initial STZ treatment, STZ induced islet cell apoptosis, while sEH inhibition in STZ mice significantly reduced islet cell apoptosis. These studies provide pharmacological evidence that inhibiting sEH activity provides significant protection against islet ?-cell damage and improves glucose homeostasis in STZ-induced diabetes.
Mesenchymal stem cells (MSC) are strongly associated with tumor progression and have been used as novel cell-based agents to deliver anticancer drugs to tumors. However, controversies about the direct involvement of MSCs in tumor progression suggest that MSCs mediate tumor progression in a cancer type-dependent manner. In this report, we analyzed the functional interactions between human MSCs and lung adenocarcinoma (LAC) cells to determine the therapeutic potential of MSCs in lung cancer. We showed that MSCs effectively inhibited the migration, invasion, and cell-cycle progression of several LAC cell lines. MSCs also enhanced the mesenchymal-epithelial transition (MET) pathway, as evidenced by the reduction of several epithelial-mesenchymal transition-related markers in LAC cells cocultured with MSCs or in MSC-conditioned medium (MSC-CM). By cytokine array analysis, we determined that Oncostatin M (OSM), a differentiation-promoting cytokine, was elevated in the MSC-CM derived from primary MSC cultures. Furthermore, OSM treatment had the same effects as MSC-CM on LAC, whereas neutralizing antibodies to OSM reversed them. Notably, short hairpin RNAs against STAT1, an important downstream target of OSM, hindered the OSM-dependent induction of MET. In vivo xenograft tumor studies indicated that OSM inhibited tumor formation and metastasis of LAC cells, whereas neutralizing OSM in the MSC-CM hampered its inhibitory effects. In conclusion, this study showed that OSM is a paracrine mediator of MSC-dependent inhibition of tumorigenicity and activation of MET in LAC cells. These effects of OSM may serve as a basis for the development of new drugs and therapeutic interventions targeting cancer cells.
Mechanical ventilation in patients may increase the risk of an acute lung injury (ALI), termed ventilator-induced lung injury (VILI). Induced pluripotent stem cells (iPSCs) have previously been shown to improve tissue repair in different disease models, including ALI. However, the therapeutic efficacy of iPSCs-derived conditioned medium (iPSC-CM) on ALI or VILI remains unknown. Here, we demonstrated that both iPSCs and iPSC-CM effectively decrease high-tidal-volume-induced VILI-related inflammatory processes and HMGB1 and PAI-1 production, predominantly through suppressing PI3K/Akt signaling. Notably, iPSC-CM suppressed production of macrophage inflammatory protein-2, malondialdehyde, and increased total glutathione content. Transmission electron microscopy revealed that iPSC-CM potentially restored the bronchial microstructure. This iPSC-CM efficacy could be mimicked by PI3K inhibitor LY294002 or Akt heterozygous knockout, and either treatment showed no further improvement on VILI in iPSC-CM recipients. Furthermore, iPSC-CM increased interferon gamma-induced protein 10 (IP-10) production in injured lungs. Administration of IP-10-neutralizing antibodies increased neutrophil infiltration, impaired lung oxygenation and deteriorated the protective effects mediated by iPSC-CM. Our data provide a preclinical indication regarding the therapeutic potential of iPSC-CM in VILI and suggest that inhibiting PI3K/Akt pathway or increasing IP-10 is a prospective diagnostic and therapeutic target for VILI patients.
Metastasis is the major cause of high mortality in head and neck squamous cell carcinoma (HNSCC), in which HNSCC-derived cancer stem cells (CSCs) may be involved. Several reports have coupled non-viral gene delivery with RNA interference (RNAi) to target specific genes in cancer cells. However, the delivery efficiency of RNAi is limited and remained to be improved. Moreover, the therapeutic effect of non-viral gene delivery approaches on HNSCC-derived CSCs is still uncertain. In this study, we found that EZH2 and Oct4 are upregulated in HNSCC-derived ALDH1+/CD44+ CSC-like cells. Polyurethane-short branch PEI (PU-PEI)-based administration of double-stranded DNA (dsDNA) encoding small interfering RNA (siRNA) against EZH2 and Oct4 (siEZH2/siOct4) led to partial anti-cancer capacity and mild suppression of CSC-like properties. By pre-conjugation of nuclear localization signal (NLS) to siRNA-expressing dsDNA, the anti-cancer efficacy was enhanced due to elevated nuclear delivery. Notably, the NLS-preconjugated siEZH2/siOct4 constructs remarkably repressed epithelial-mesenchymal transdifferentiation (EMT) and radioresistance in ALDH1+/CD44+ CSC-like cells, in which Wnt5A and CyclinD1 may be involved respectively. We furthermore demonstrated that this improved method was capable of reducing tumor growth and metastasis in vivo. Our findings may provide a feasible non-viral gene delivery method to eradicate HNSCC-derived CSCs and improve HNSCC therapy.
The high invasiveness and frequent recurrence of lung adenocarcinoma (LAC) are major reasons for treatment failures and poor prognoses. Alterations in microRNAs (miRNAs) expression have been shown in lung cancers. Recent reports have demonstrated that tumors contain a small subpopulation of cancer stem cells (CSCs) that possesses self-renewing capacity and is responsible for tumor malignancy including metastasis, relapse, and chemoradioresistance. However, a miRNAs-based therapeutic approach in LAC-associated CSCs (LAC-CSCs) is still blurred. Using miRNA/mRNA-microarray and Quantitative RT-PCR, we found that the expression of miR145 is negatively correlated with the levels of Oct4/Sox2/Fascin1 in LAC patient specimens, and an Oct4(high)Sox2(high)Fascin1(high)miR145(low) phenotype predicted poor prognosis. We enriched LAC-CSCs by side population sorting or identification of CD133 markers and found that LAC-CSCs exhibited low miR145 and high Oct4/Sox2/Fascin1 expression, CSC-like properties, and chemoradioresistance. To clarify the role of miR145, we used a polyurethane-short branch-polyethylenimine (PU-PEI) as the vehicle to deliver miR145 into LAC-CSCs. PU-PEI-mediated miR145 delivery reduced CSC-like properties, and improved chemoradioresistance in LAC-CSCs by directly targeting Oct4/Sox2/Fascin1. Importantly, the repressive effect of miR145 on tumor metastasis was mediated by inhibiting the epithelial-mesenchymal transdifferentiation (EMT) and metastastic ability, partially by regulating Oct4/Sox2/Fascin1, Tcf4, and Wnt5a. Finally, in vivo study showed that PU-PEI-mediated miR145 delivery to xenograft tumors reduced tumor growth and metastasis, sensitized tumors to chemoradiotherapies, and prolonged the survival times of tumor-bearing mice. Our results demonstrated that miR145 acts as a switch regulating lung CSC-like and EMT properties, and provide insights into the clinical prospect of miR145-based therapies for malignant lung cancers.
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