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Find video protocols related to scientific articles indexed in Pubmed.
Systematic dissection of the mechanisms underlying progesterone receptor downregulation in endometrial cancer.
Oncotarget
PUBLISHED: 09-18-2014
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Progesterone, acting through its receptor, PR (progesterone receptor), is the natural inhibitor of uterine endometrial carcinogenesis by inducing differentiation. PR is downregulated in more advanced cases of endometrial cancer, thereby limiting the effectiveness of hormonal therapy. Our objective was to understand and reverse the mechanisms underlying loss of PR expression in order to improve therapeutic outcomes. Using endometrial cancer cell lines and data from The Cancer Genome Atlas, our findings demonstrate that PR expression is downregulated at four distinct levels. In well-differentiated cancers, ligand-induced receptor activation and downregulation are intact. miRNAs mediate fine tuning of PR levels. As differentiation is lost, PR silencing is primarily at the epigenetic level. Initially, recruitment of the polycomb repressor complex 2 to the PR promoter suppresses transcription. Subsequently, DNA methylation prevents PR expression. Appropriate epigenetic modulators reverse these mechanisms. These data provide a rationale for combining epigenetic modulators with progestins as a therapeutic strategy for endometrial cancer.
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Gene cloning, expression and immunogenicity of the protective antigen subolesin in Dermacentor silvarum.
Korean J. Parasitol.
PUBLISHED: 02-19-2014
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Subolesin (4D8), the ortholog of insect akirins, is a highly conserved protective antigen and thus has the potential for development of a broad-spectrum vaccine against ticks and mosquitoes. To date, no protective antigens have been characterized nor tested as candidate vaccines against Dermacentor silvarum bites and transmission of associated pathogens. In this study, we cloned the open reading frame (ORF) of D. silvarum 4D8 cDNA (Ds4D8), which consisted of 498 bp encoding 165 amino acid residues. The results of sequence alignments and phylogenetic analysis demonstrated that D. silvarum 4D8 (Ds4D8) is highly conserved showing more than 81% identity of amino acid sequences with those of other hard ticks. Additionally, Ds4D8 containing restriction sites was ligated into the pET-32(a+) expression vector and the recombinant plasmid was transformed into Escherichia coli rosetta. The recombinant Ds4D8 (rDs4D8) was induced by isopropyl ?-D-thiogalactopyranoside (IPTG) and purified using Ni affinity chromatography. The SDS-PAGE results showed that the molecular weight of rDs4D8 was 40 kDa, which was consistent with the expected molecular mass considering 22 kDa histidine-tagged thioredoxin (TRX) protein from the expression vector. Western blot results showed that rabbit anti-D. silvarum serum recognized the expressed rDs4D8, suggesting an immune response against rDs4D8. These results provided the basis for developing a candidate vaccine against D. silvarum ticks and transmission of associated pathogens.
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Comprehensive profiling of EGFR/HER receptors for personalized treatment of gynecologic cancers.
Mol Diagn Ther
PUBLISHED: 01-10-2014
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The primary gynecologic cancers include cancers of the endometrium, ovary, and cervix. Worldwide, cervical cancer is the most common gynecologic cancer, whereas endometrial cancer is the most common in the US. Ovarian cancer is the fifth most deadly cancer in women, with 5-year survival rates for advanced disease at only 27 %. As such, there is an urgent need for reliable screening tools and novel targeted therapeutic regimens for these malignancies. The epidermal growth factor receptor (EGFR)/human EGFR (HER) family of receptors has been associated with the development and progression of many solid tumors. Despite clear roles for these receptors in other cancers, the expression of HER family members in gynecologic cancers and their relationship with disease stage, grade, and response to treatment remain controversial. In this review, we describe the existing evidence for the use of HER family members as diagnostic and prognostic indicators as well as their potential as therapeutic targets in gynecologic cancers.
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ErbB3 is an active tyrosine kinase capable of homo- and hetero-interactions.
Mol. Cell. Biol.
PUBLISHED: 12-30-2013
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Often considered to be a "dead" kinase, erbB3 is implicated in escape from erbB-targeted cancer therapies. Here, heregulin stimulation is shown to markedly upregulate kinase activity in erbB3 immunoprecipitates. Intact, activated erbB3 phosphorylates tyrosine sites in an exogenous peptide substrate and this activity is abolished by mutagenesis of lysine 723 in the catalytic domain. Enhanced erbB3 kinase activity is linked to heterointeractions with catalytically active erbB2, since it is largely blocked in cells pretreated with lapatinib or pertuzumab. ErbB2 activation of erbB3 is not dependent on equal surface levels of these receptors, since it occurs even in erbB3-transfected CHO cells with disproportionally low amounts of erbB2. We tested a model in which transient erbB3/erbB2 heterointeractions set the stage for erbB3 homodimers to be signaling competent. ErbB3 homo- and hetero-dimerization events were captured in real time on live cells using single particle tracking of quantum dot probes bound to ligand or HA-tags on recombinant receptors.
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Multiple lines of evidence on the genetic relatedness of the parthenogenetic and bisexual Haemaphysalis longicornis (Acari: Ixodidae).
Infect. Genet. Evol.
PUBLISHED: 08-01-2013
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As an obligate hematophagous ectoparasite, the hard tick Haemaphysalis longicornis exhibits two reproductive strategies, bisexual reproduction, and obligate parthenogenesis, which have attracted a widespread attention. However, the speciation of parthenogenetic population remained ambiguous due to its similarity in morphology but the remarkable differences in cytogenetics as compared with those of the bisexual ones. In the present study, we explored several new lines of genetic evidence to resolve this controversial issue. The number of the chromosomes in two lineages was checked by classical methods and their total DNA levels were determined utilizing flowcytometry. In addition, the sequences of 12S rDNA, 16S rDNA, cytochrome c oxidase I and II (COI, COII) and internal transcribed spacer-2 (ITS-2) genes were used to assess their phylogenetic relationship. We observed that the chromosome ploidy of bisexual and parthenogenetic H. longicornis collected by our laboratory was diploid and triploid, respectively. Flowcytometry analysis indicated a ratio close to 2:3 in the DNA contents of bisexual to parthenogenetic H. longicornis. Although the chromosome ploidy is different, their gene sequences are extremely similar. Analogous to the intra-species genetic difference of other invertebrates, sequence differences of all loci examined are below 2%. Phylogenetic trees constructed from 12S rDNA, 16S rDNA, COI, and ITS-2 genes revealed that they were all in the same monophyletic clade instead of splitting independently into evolutional branches. Moreover, according to 4× Rule, the K/? ratio of two reproductive populations calculated based on COI was much smaller than four, strongly supporting that they belong to the same species. Therefore, we conclude that the evolutionary process just disturbs the chromosome ploidy and the sexual determination of parthenogenetic population and that it would be better to consider parthenogenetic H. longicornis as a metapopulation rather than a cryptic species.
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The Estrogen Receptor Joins Other Cancer Biomarkers as a Predictor of Outcome.
Obstet Gynecol Int
PUBLISHED: 06-17-2013
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Endometrial cancer, the most common gynecologic malignancy in the United States, is on the rise, and survival is worse today than 40 years ago. In order to improve the outcomes, better biomarkers that direct the choice of therapy are urgently needed. In this review, we explore the estrogen receptor as the most studied biomarker and the best predictor for response for endometrial cancer reported to date.
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Strategies for Molecularly Enhanced Chemotherapy to Achieve Synthetic Lethality in Endometrial Tumors with Mutant p53.
Obstet Gynecol Int
PUBLISHED: 05-31-2013
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Serous uterine endometrial carcinomas are aggressive type II cancers with poor outcomes for which new treatment strategies are urgently needed, in particular, strategies that augment sensitivity to established chemotherapy regimens. The tumor suppressor gene TP53 is dysregulated in more than 90% of serous tumors, altering master regulators of the G2/M cell cycle checkpoint in unique and predictable ways and desensitizing cells to chemotherapy. We hypothesized that synthetic lethality can be achieved in endometrial cancer cells with mutant p53 by combining paclitaxel with agents to overcome G2/M arrest and induce mitotic catastrophe. The combination of BIBF1120, an investigational VEGFR, PDGFR, and FGFR multityrosine kinase inhibitor with established anti-angiogenic activity, with paclitaxel abrogated the G2/M checkpoint in p53-null endometrial cancer cells via modulation of G2/M checkpoint regulators followed by induction of mitotic cell death. In endometrial cancer cells harboring an oncogenic gain-of-function p53 mutation, synthetic lethality was created by combining paclitaxel with BIBF1120 and a histone deacetylase inhibitor, which serves to destabilize mutant p53. These cells were also sensitive to an inhibitor of the G2/M kinase Wee1 in combination with paclitaxel. These findings reveal that, in addition to antiangiogenic activity, the angiokinase inhibitor BIBF1120 can be used to restore sensitivity to paclitaxel and induce mitotic cell death in endometrial cancer cells with non-functional p53. These preclinical data serve as a critical platform for the creative design of future clinical trials utilizing molecularly enhanced chemotherapy to achieve synthetic lethality based on the mutational landscape.
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Screening and molecular cloning of a protective antigen from the midgut of Haemaphysalis longicornis.
Korean J. Parasitol.
PUBLISHED: 01-23-2013
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Vaccination is considered a promising alternative for controlling tick infestations. Haemaphysalis longicornis midgut proteins separated by SDS-PAGE and transferred to polyvinylidene difluoride (PVDF) membrane were screened for protective value against bites. The western blot demonstrated the immunogenicity of 92 kDa protein (P92). The analysis of the P92 amino acid sequence by LC-MS/MS indicated that it was a H. longicornis paramyosin (Hl-Pmy). The full lenghth cDNA of Hl-Pmy was obtained by rapid amplification of cDNA ends (RACE) which consisted of 2,783 bp with a 161 bp 3 untranslated region. Sequence alignment of tick paramyosin (Pmy) showed that Hl-Pmy shared a high level of conservation among ticks. Comparison with the protective epitope sequence of other invertebrate Pmy, it was calculated that the protective epitope of Hl-Pmy was a peptide (LEEAEGSSETVVEMNKKRDTE) named LEE, which was close to the N-terminal of Hl-Pmy protein. The secondary structure analysis suggested that LEE had non-helical segments within an ?-helical structure. These results provide the basis for developing a vaccine against biting H. longicornis ticks.
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Correlation of MTDH/AEG-1 and HOTAIR Expression with Metastasis and Response to Treatment in Sarcoma Patients.
J Cancer Sci Ther
PUBLISHED: 12-29-2011
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Chemoresistance and metastasis are the main reasons for the failure of current treatments with sarcoma patients. Novel biomarkers are required to predict metastasis and response to treatment. The oncogene MTDH/AEG1 and the long noncoding RNA (lincRNA) HOTAIR are two novel factors involved in drug resistance and metastasis in various types of solid tumors. However, the correlation between MTDH/AEG-1 and HOTAIR expression with metastasis and drug resistance in sarcoma is unknown.
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Cytoplasmic Metadherin (MTDH) provides survival advantage under conditions of stress by acting as RNA-binding protein.
J. Biol. Chem.
PUBLISHED: 12-23-2011
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Overexpression of metadherin (MTDH) has been documented in many solid tumors and is implicated in metastasis and chemoresistance. MTDH has been detected at the plasma membrane as well as in the cytoplasm and nucleus, and the function of MTDH in these locales remains under investigation. In the nucleus, MTDH acts as a transcription co-factor to induce expression of chemoresistance-associated genes. However, MTDH is predominantly cytoplasmic in prostate tumors, and this localization correlates with poor prognosis. Herein, we used endometrial cancer cells as a model system to define a new role for MTDH in the cytoplasm. First, MTDH was primarily localized to the cytoplasm in endometrial cancer cells, and the N-terminal region of MTDH was required to maintain cytoplasmic localization. Next, we identified novel binding partners for cytoplasmic MTDH, including RNA-binding proteins and components of the RNA-induced silencing complex. Nucleic acids were required for the association of MTDH with these cytoplasmic proteins. Furthermore, MTDH interacted with and regulated protein expression of multiple mRNAs, such as PDCD10 and KDM6A. Depletion of cytoplasmic MTDH was associated with increased stress granule formation, reduced survival in response to chemotherapy and the tyrosine kinase inhibitor BIBF1120, Rad51 nuclear accumulation, and cell cycle arrest at G(2)/M. Finally, in vivo tumor formation was abrogated with knockdown of cytoplasmic MTDH. Taken together, our data identify a novel function for cytoplasmic MTDH as an RNA-binding protein. Our findings implicate cytoplasmic MTDH in cell survival and broad drug resistance via association with RNA and RNA-binding proteins.
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Endometrial cancer: reviving progesterone therapy in the molecular age.
Discov Med
PUBLISHED: 09-30-2011
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Endometrial cancer is the most common gynecologic malignancy and represents a major health concern because overall five-year survival rates have not improved in the last three decades. A great deal of research demonstrates that the endometrium is extremely sensitive to hormones, and a shift in the estrogen:progesterone balance is the major cause for the development of endometrial cancer. Progestin-based therapy has proven effective in a subset of patients, particularly in situations where expression of progesterone receptor (PR) is maintained. However, this approach is not routinely used in the clinic in the U.S. for several reasons. For example, many endometrial tumors have lost PR expression, which limits the clinical application of progestin-based therapy. While the idea that restoring PR expression will resensitize tumors to progestin was proposed over 20 years ago, we only now have the molecular tools to accomplish this goal. Basic science research has revealed several pathways that govern the expression of PR at the DNA, RNA, and protein levels. In this article, we describe one current approach to restore expression of PR at the epigenetic level in endometrial cancer. While still in the preclinical stage, we believe this strategy to re-establish PR expression will result in resensitization of endometrial tumors to progestin therapy.
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A mechanism for synergy with combined mTOR and PI3 kinase inhibitors.
PLoS ONE
PUBLISHED: 06-06-2011
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Dysregulation of the mammalian target of rapamycin (mTOR) signaling has been found in many human cancers, particularly those with loss of the tumor suppressor PTEN. However, mTORC1 inhibitors such as temsirolimus have only modest activity when used alone and may induce acquired resistance by activating upstream mTORC2 and Akt. Other tumors that do not depend upon PI3K/Akt/mTOR signaling for survival are primarily resistant. This study tested the hypothesis that the limited clinical efficacy of temsirolimus is due to a compensatory increase in survival signaling pathways downstream of Akt as well as an incomplete block of 4E-BP1-controlled proliferative processes downstream of mTOR. We explored the addition of a PI3K inhibitor to temsirolimus and identified the mechanism of combinatorial synergy. Proliferation assays revealed that BEZ235 (dual PI3K/mTOR inhibitor) or ZSTK474 (pan PI3K inhibitor) combined with temsirolimus synergistically inhibited cell growth compared to cells treated with any of the agents alone. Co-treatment resulted in G0/G1 cell cycle arrest and up-regulation of p27. Cell death occurred through massive autophagy and subsequent apoptosis. While molecular profiling revealed that, in most cases, sensitivity to temsirolimus alone was most marked in cells with high basal phospho-Akt resulting from PTEN inactivation, combining a PI3K inhibitor with temsirolimus prevented compensatory Akt phosphorylation and synergistically enhanced cell death regardless of PTEN status. Another molecular correlate of synergy was the finding that temsirolimus treatment alone blocks downstream S6 kinase signaling, but not 4E-BP1. Adding BEZ235 completely abrogated 4E-BP1 phosphorylation. We conclude that the addition of a PI3K inhibitor overcomes cellular resistance to mTORC1 inhibitors regardless of PTEN status, and thus substantially expands the molecular phenotype of tumors likely to respond.
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Knockdown of MTDH sensitizes endometrial cancer cells to cell death induction by death receptor ligand TRAIL and HDAC inhibitor LBH589 co-treatment.
PLoS ONE
PUBLISHED: 05-16-2011
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Understanding the molecular underpinnings of chemoresistance is vital to design therapies to restore chemosensitivity. In particular, metadherin (MTDH) has been demonstrated to have a critical role in chemoresistance. Over-expression of MTDH correlates with poor clinical outcome in breast cancer, neuroblastoma, hepatocellular carcinoma and prostate cancer. MTDH is also highly expressed in advanced endometrial cancers, a disease for which new therapies are urgently needed. In this present study, we focused on the therapeutic benefit of MTDH depletion in endometrial cancer cells to restore sensitivity to cell death. Cells were treated with a combination of tumor necrosis factor-?-related apoptosis-inducing ligand (TRAIL), which promotes death of malignant cells of the human reproductive tract, and histone deacetylase (HDAC) inhibitors, which have been shown to increase the sensitivity of cancer cells to TRAIL-induced apoptosis. Our data indicate that depletion of MTDH in endometrial cancer cells resulted in sensitization of cells that were previously resistant in response to combinatorial treatment with TRAIL and the HDAC inhibitor LBH589. MTDH knockdown reduced the proportion of cells in S and increased cell arrest in G2/M in cells treated with LBH589 alone or LBH589 in combination with TRAIL, suggesting that MTDH functions at the cell cycle checkpoint to accomplish resistance. Using microarray technology, we identified 57 downstream target genes of MTDH, including calbindin 1 and galectin-1, which may contribute to MTDH-mediated therapeutic resistance. On the other hand, in MTDH depleted cells, inhibition of PDK1 and AKT phosphorylation along with increased Bim expression and XIAP degradation correlated with enhanced sensitivity to cell death in response to TRAIL and LBH589. These findings indicate that targeting or depleting MTDH is a potentially novel avenue for reversing therapeutic resistance in patients with endometrial cancer.
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Progesterone: the ultimate endometrial tumor suppressor.
Trends Endocrinol. Metab.
PUBLISHED: 01-11-2011
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The uterine endometrium is exquisitely sensitive to steroid hormones that act through well-described nuclear receptors. Estrogen drives epithelial proliferation, and progesterone inhibits growth and causes cell differentiation. The importance of progesterone as a key inhibitor of carcinogenesis is reflected by the observation that women who ovulate and produce progesterone almost never get endometrial cancer. In this review we describe seminal research findings that define progesterone as the major endometrial tumor suppressor. We discuss the genes and diverse signaling pathways that are controlled by progesterone through progesterone receptors (PRs) and also the multiple factors that regulate progesterone/PR activity. By defining these progesterone-regulated factors and pathways we identify the principal therapeutic opportunities to control the growth of endometrial cancer.
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Spatio-temporal modeling of signaling protein recruitment to EGFR.
BMC Syst Biol
PUBLISHED: 05-06-2010
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A stochastic simulator was implemented to study EGFR signal initiation in 3D with single molecule detail. The model considers previously unexplored contributions to receptor-adaptor coupling, such as receptor clustering and diffusive properties of both receptors and binding partners. The agent-based and rule-based approach permits consideration of combinatorial complexity, a problem associated with multiple phosphorylation sites and the potential for simultaneous binding of adaptors.
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Induction of mitotic cell death by overriding G2/M checkpoint in endometrial cancer cells with non-functional p53.
Gynecol. Oncol.
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Endometrial tumors with non-functional p53, such as serous uterine endometrial carcinomas, are aggressive malignancies with a poor outcome, yet they have an Achilles heel: due to loss of p53 function, these tumors may be sensitive to treatments which abrogate the G2/M checkpoint. Our objective was to exploit this weakness to induce mitotic cell death using two strategies: (1) EGFR inhibitor gefitinib combined with paclitaxel to arrest cells at mitosis, or (2) BI2536, an inhibitor of polo-like kinase 1 (PLK1), to block PLK1 activity.
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Catch it before it kills: progesterone, obesity, and the prevention of endometrial cancer.
Discov Med
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The lifetime risk for developing endometrial cancer, the fourth most common malignancy in women, is approximately 3%. Endometrial cancer is a hormone-driven cancer, with approximately 80% of endometrial cancers arising attributable to either an excess of estrogen or a lack of progesterone. In the normal endometrium, the proliferative effects of estrogen are normally countered by progesterone, but the absence of progesterone allows estrogen to induce oncogenesis, an effect that is amplified in situations of excess estrogen. One of the major emerging causes of the estrogen/progesterone imbalance is obesity. Obesity is associated with several hormonal derangements as well as dysregulation of insulin/insulin-like growth factor activity, which collectively contribute to hyperplasia and carcinogenesis in the endometrium. In this article, we provide an in-depth description of how obesity mechanistically promotes this hormone and growth factor imbalance. Given that endometrial cancer is clearly associated with obesity, we put forth the hypothesis that a large portion of these cancers might be prevented by treatment with progesterone.
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Characterization of diverse antimicrobial peptides in skin secretions of Chungan torrent frog Amolops chunganensis.
Peptides
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We have cloned, synthesized, and characterized 11 novel antimicrobial peptides from a skin derived cDNA library of the Chungan torrent frog, Amolops chunganensis. Seven of the 11 antimicrobial peptides were present in authentic A. chunganensis skin secretions. Sequence analysis indicated that the 11 peptides belonged to the temporin, esculentin-2, palustrin-2, brevinin-1, and brevinin-2 families. The peptides displayed potent antimicrobial activities against several strains of microorganisms. One peptide, brevinin-1CG5, demonstrated antimicrobial activity against all tested Gram-positive and Gram-negative bacteria and fungi, and showed high antimicrobial potency (MIC=0.6 ?M) against Gram-positive bacterium Rhodococcus rhodochrous. Some peptides also demonstrated weak hemolytic activity against human erythrocytes in vitro. Phylogenetic analysis based on the amino acid sequences of brevinin-1, brevinin-2, and esculentin-2 peptides from family Ranidae confirmed that the current taxonomic status of A. chunganensis is correct.
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Endometrial cancer.
Obstet. Gynecol. Clin. North Am.
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Despite the questions and barriers, the incorporation of molecular therapy into treatment regimens in endometrial cancer is an exciting area of investigation with the potential to improve outcomes. Outside of the development of a reliable screening test for endometrial cancer, converting the disease to a chronic state and improving progression-free survival is our best hope to reverse the concerning trend of decreasing 5-year survival for this disease.
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Novel antimicrobial peptides isolated from the skin secretions of Hainan odorous frog, Odorrana hainanensis.
Peptides
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Long time geographical isolation of Hainan Island from the China continent has resulted in appearance of many novel frog species. As one of them, Hainan odorous frog, Odorrana hainanensis possesses some special antimicrobial peptides distinct from those found in other Odorrana. In this study, three antimicrobial peptides have been purified and characterized from the skin secretion of O. hainanensis. With the similarity to the temporin family, two peptides are characterized by amidated C-terminals, so they are named as temporin-HN1 (AILTTLANWARKFL-NH(2)) and temporin-HN2 (NILNTIINLAKKIL-NH(2)). The third antimicrobial peptide belongs to the brevinin-1 family which is widely distributed in Eurasian ranids, and thus, it is named as brevinin-1HN1 (FLPLIASLAANFVPKIFCKITKKC). Furthermore, after sequencing 68 clones, eight cDNAs encoding antimicrobial peptide precursors were cloned from the skin-derived cDNA library of O. hainanensis. These eight cDNAs can encode seven mature antimicrobial peptides including the above three, as well as brevinin-1V, brevinin-2HS2, odorranain-A6, and odorranain-B1. Twelve different species of microorganisms were chosen, including Gram-positive, Gram-negative and fungi, to test the antimicrobial activities of temporin-HN1, temporin-HN2, brevinin-1HN1, brevinin-1V, and brevinin-2HS2. The result shows that, in addition to their activities against Gram-positive bacteria, temporin-HN1 and temporin-HN2 also possess activities against some Gram-negative bacteria and fungi. However, the two antimicrobial peptides, brevinin-1HN1 and brevinin-1V of the brevinin-1 family have stronger antimicrobial activities than temporin-HN1 and temporin-HN2 of the temporin family. Brevinin-1HN1 possesses activity against Staphylococcus aureus (ATCC25923), Rhodococcus rhodochrous X15, and Slime mould 090223 at the concentration of 1.2 ?M.
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Molecular cloning and characterization of antimicrobial peptides from skin of the broad-folded frog, Hylarana latouchii.
Biochimie
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Seven cDNA sequences encoding antimicrobial peptide (AMP) precursors were cloned by screening the skin-derived cDNA library of the broad-folded frog, Hylarana latouchii. Seven of the deduced peptides are highly similar to AMPs in five families of brevinin-2 (brevinin-2LTa, brevinin-2LTb, and brevinin-2LTc), esculentin-1 (esculentin-1LTa), esculentin-2 (esculentin-2LTa), palustrin-2 (palustrin-2LTa), and temporin (temporin-LTe). The actual sequences and characteristics of mature AMPs were analyzed by RP-HPLC and LC-MS/MS-based proteomics approaches in combination of four different protein digestion processes and by LTQ XL in combination of gas-phase fractionation (GPF) analysis. Moreover, most of the peptides found in this study hardly display hemolytic activity in vitro, suggesting they are promising antimicrobial drug candidates.
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Epigenetic Modification Restores Functional PR Expression in Endometrial Cancer Cells.
Curr. Pharm. Des.
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Endometrial cancer, the most common gynecologic malignancy, is a hormonally-regulated tumor. Response to progestin-based therapy correlates positively with progesterone receptor (PR) expression. However, many endometrial tumors have low levels or loss of PR, limiting the clinical application of progestin. We evaluated the ability of epigenetic modulators to restore functional PR expression in Type I endometrial cancer cells with low basal PR. Treatment with the histone deacetylase inhibitor (HDACi) LBH589 induced a profound upregulation of PR mRNA. LBH589 restored PR protein expression at 24 hours and sustained expression for 72 hours, even in the presence of progesterone. LBH589 promoted a dose-dependent increase in PR protein levels, with an obvious increase with 10 nM LBH589. To investigate if the restored PR is functional as a transcription factor, we examined PR nuclear localization and expression of PRE- or Sp1-containing target genes. After treatment with LBH589 in the absence or presence of progesterone, PR nuclear expression was increased as demonstrated by Western blotting of nuclear fractions and immunostaining. Next, restored PR upregulated FoxO1, p21, and p27 and downregulated cyclin D1 in a ligand-dependent manner. Finally, LBH589 treatment induced cell cycle arrest in G1 that was further augmented by progesterone. Regulation of PR target genes was also achieved with other HDAC inhibitors, indicating that agents in this class work similarly with respect to PR. Our findings reveal that epigenetic modulators can restore endogenous functional PR expression in endometrial cancer cells and suggest that strategies to re-establish PR expression will resensitize endometrial tumors to progestin therapy.
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What is Visualize?

JoVE Visualize is a tool created to match the last 5 years of PubMed publications to methods in JoVE's video library.

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We use abstracts found on PubMed and match them to JoVE videos to create a list of 10 to 30 related methods videos.

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In developing our video relationships, we compare around 5 million PubMed articles to our library of over 4,500 methods videos. In some cases the language used in the PubMed abstracts makes matching that content to a JoVE video difficult. In other cases, there happens not to be any content in our video library that is relevant to the topic of a given abstract. In these cases, our algorithms are trying their best to display videos with relevant content, which can sometimes result in matched videos with only a slight relation.