Stem cell transcription factor NANOG controls cell migration and invasion via dysregulation of E-cadherin and FoxJ1 and contributes to adverse clinical outcome in ovarian cancers

Ovarian cancer is the most lethal of all gynecological malignancies, and the identification of novel prognostic and therapeutic targets for ovarian cancer is crucial. It is believed that only a small subset of cancer cells are endowed with stem cell properties, which are responsible for tumor growth, metastatic progression and recurrence. NANOG is one of the key transcription factors essential for maintaining self-renewal and pluripotency in stem cells. This study investigated the role of NANOG in ovarian carcinogenesis and showed overexpression of NANOG mRNA and protein in the nucleus of ovarian cancers compared with benign ovarian lesions. Increased nuclear NANOG expression was significantly associated with high-grade cancers, serous histological subtypes, reduced chemosensitivity, and poor overall and disease-free survival. Further analysis showed NANOG is an independent prognostic factor for overall and disease-free survival. Moreover, NANOG was highly expressed in ovarian cancer cell lines with metastasis-associated property and in clinical samples of metastatic foci. Stable knockdown of NANOG impeded ovarian cancer cell proliferation, migration and invasion, which was accompanied by an increase in mRNA expression of E-cadherin, caveolin-1, FOXO1, FOXO3a, FOXJ1 and FOXB1. Conversely, ectopic NANOG overexpression enhanced ovarian cancer cell migration and invasion along with decreased E-cadherin, caveolin-1, FOXO1, FOXO3a, FOXJ1 and FOXB1 mRNA expression. Importantly, we found Nanog-mediated cell migration and invasion involved its regulation of E-cadherin and FOXJ1. This is the first report revealing the association between NANOG expression and clinical outcome of patients with ovarian cancers, suggesting NANOG to be a potential prognostic marker and therapeutic molecular target in ovarian cancer.Oncogene advance online publication, 3 September 2012; doi:10.1038/onc.2012.363.postprin

TrkB as a therapeutic target for ovarian cancer

Background: In many countries, ovarian cancer is the most lethal gynecological malignancy. Its poor prognosis is mainly due to the late stage of disease with metastasis at presentation. The significant failure rate of chemotherapy in patients with advanced stage disease is also a main concern. As such, developing novel therapeutic targets is essential to improve long-term survival. Overexpression of Tropomyosin-related kinase B (TrkB), a tyrosine kinase receptor, has been documented in ovarian cancer and is found to be correlated with poor prognosis. Objective/methods: We discuss the functional roles and the related downstream signaling pathways of TrkB and its ligand brain-derived neurotrophic factor (BDNF) in ovarian cancer. The possible crosstalk between TrkB/BDNF and other putative molecular targets in ovarian cancer is also discussed. Results/conclusions: All these latest findings shed light on the application of TrkB as a therapeutic target for ovarian cancer. © 2009 Informa UK Ltd All rights reserved.link_to_subscribed_fulltex

iASPP and chemoresistance in ovarian cancers: paclitaxel-mediated mitotic catastrophe and apoptosis

Workshop

Efficacy of Abbott RealTime High Risk HPV test in evaluation of atypical squamous cells of undetermined significance from an Asian screening population

Background: Abbott RealTime High Risk HPV test is a new qualitative real-time PCR assay for the detection of 14 high risk HPV (HR-HPV) types and specific identification of HPV16 and HPV18. For each new HPV DNA test, it is important to validate its clinical performance using established tests as benchmarks. Hybrid Capture 2 (HC2) is the first USA FDA-approved HR-HPV DNA test. Objectives: To compare the performance of Abbott RealTime High Risk HPV test with that of Hybrid Capture 2 in detecting cytology samples with varying prognosis. Study design: 250 liquid-based cervical cytology samples diagnosed of Atypical Squamous cells of Undetermined Significance (ASC-US) collected from an Asian Screening Population were independently tested with both Abbott RealTime High Risk HPV test and HC2. Their utility in predicting disease progression was evaluated in 82 of the samples for which follow up cytology or colposcropic histology data was available. Results: Good to excellent agreement between the two tests was demonstrated (Kappa = 0.800, 95% CI: 0.726-0.874). The sensitivity, specificity, positive (PPV) and negative predictive values (NPV) of the two tests in detecting cases with underlying HSIL/CIN2+ were evaluated (Abbott: 100%, 20.83%, 14.93% and 100% respectively; HC2: 100%, 12.50%, 13.70% and 100% respectively). HPV16/18 genotyping provided by the Abbott test enhanced specific identification of cases with LSIL/CIN1+ (specificity 91.30%, PPV 84.62%) and HSIL/CIN2+ (specificity 86.11%, PPV 23.08%) at follow-up. Conclusions: The Abbott test performed similarly to HC2 and is unlikely to be affected by ethnicity. Abbott combined HPV detection and HPV 16/18 genotyping is found to provide enhanced sensitivity and specificity for triage of ASC-US. © 2011 Elsevier B.V.link_to_subscribed_fulltex

Dysregulated expression and function of Plexin-β1 in ovarian cancers

Poster Session 9 - PO.CB01.04. Signaling in Tumors 1: abstract no. 3183BACKGROUND: Ovarian cancer has a tendency to spread within the peritoneal cavity early in the disease course. Understanding the metastatic pathways of ovarian cancer is thus of high importance for devising ovarian cancer treatment. Plexin-B1 is a cognate receptor of Semaphorin 4D (Sema4D). This study aims at investigating the role of Plexin-B1 in ovarian cancer. MATERIALS AND METHODS: Expression of Plexin-B1 and its ligand in ovarian epithelial cell lines was examined by western blot and qPCR. Their expression in benign, borderline, and malignant tumors was revealed by immunohistochemistrty of paraffin embedded tissues. High-resolution melting (HRM) curve analysis was used to screen for mutation in Rac binding region of PLXNB1. Recombinant Sema4D was purified and used to treat OVCA420 cells which express high level of Plexin-B1. siRNA was used to knock-down Plexin-B1 in OVCA420. Cell migration and invasion ability was assayed by transwell migration and invasion assay. RESULTS: Plexin-B1 was most highly overexpressed in serous ovarian cancer cell lines OVCA420, OVCA429, and SW626, whereas Sema4D was overexpressed in OVCAR3, TOV21G, and PAI. In contrast, Plexin-B1 and Sema4D were not expressed in immortalized normal ovarian epithelial cell lines. Immunohistochemical studies also revealed high Plexin B1 expression in ovarian borderline tumors and invasive cancers while no Plexin B1 expression was detectable in benign tumor. On the other hand, downregulation of Plexin-B1 was observed in the metastatic foci compared with their corresponding primary tumors. There is also a tendency of higher Plexin-B1 expression in serous histotype than in other histotypes. A preliminary HRM screening of Plexin-B1 cDNA from 28 ovarian cancers detected no mutation in the Rac binding region. Knock-down of Plexin-B1 by siRNA caused increased migration and invasion of ovarian cancer cells. In contrast to Sema4D, treatment of ovarian cancer cells OVCA420 by follicle-stimulating hormone which enhances ovarian cancer growth, led to Plexin-B1 downregulation. CONCLUSION: Our study suggested that Plexin-B1 may contribute to early ovarian carcinogenesis. Its dyregulation in ovarian cancers is paradoxically associated with altered cancer cell invasion and migration. The role of Plexin B1 in ovarian cancer progression is complex.link_to_OA_fulltextThe 101st Annual Meeting of the American Association for Cancer Research (AACR 2010), Washington D.C., 17-21 April 2010

Expression of napsin A in Arias Stella reaction: an analysis of 40 cases

Gynecologic and Obstetric Pathology: Poster Session 2 - no. 12

Yeast arginine methyltransferase Hmt1p regulates transcription elongation and termination by methylating Npl3p

The 11th CSHL Meeting on Transcriptional Regulation in Eukaryotes, Cold Spring Harbor, N.Y., 25-29 August 2009

Dysregulated expression of stem cell transcription factor Nanog in development and progress of ovarian cancers

Poster Session 14 - PO.TB02.05: Cancer Stem Cell Biology 1: abstract no. 4233Introduction: Ovarian cancer is the most lethal of all gynecological malignacies due to its lack of symptoms at early stages. In addition, widespread intraperitoneal metastases and malignant ascites frequently develop. Therefore, it is very important to identify novel prognostic and therapeutic targets for this cancer. Many researchers believe that only a small subset of cancer cells are endowed with stem cell properties, which are responsible for tumor growth, metastatic progression and recurrence. Nanog is one of core transcription factors essential for the maintaining self-renewal and pluripotency in stem cells. This study investigated the clinical significance, functional roles and putative downstream targets of Nanog in ovarian cancer. Methods and Results: Differential protein expression profile of Nanog in clinical samples, including benign (n=6), borderline (n=7), carcinomas (n=97) and metastatic foci (n=24) were determined by immunohistochemistry. Differential mRNA expression pattern of Nanog in 3 normal ovarian epithelial cell lines, 16 ovarian cancer cell lines was assessed by quantitative real-time polymerase chain reaction. Subcellular localization of Nanog was performed by Western blotting. Nanog was found to be localized in the nucleus of ovarian cancers. High Nanog expression in ovarian cancers was significantly associated with high grade tumors, serous histological type and chemoresistance (p<0.05). Importantly, Nanog was found to be highly expressed in ovarian cancer cell lines with metastasis-associated property and in clinical samples of metastatic foci. Elevated Nanog expression was associated with poor overall and disease-free survival in the univariate analysis. Nanog expression became one of the independent prognostic factors in the multivariate analysis for overall but not disease-free survival. By Transwell migration and invasion assays, stable knockdown of Nanog in ovarian cancer cell line, OVCAR-3, impeded cell migration and invasion. Stable knockdown of Nanog also increased mRNA expression of E-cadherin (an essential epithelial mesenchymal transition marker, thus related to metastasis) and FOXO1A (an important gene related to chemoresistance). Conclusion: Nanog was associated with progression of ovarian tumors, patients’ overall survival and chemoresistance, suggesting that Nanog can be one of the potential prognostic markers and therapeutic molecular targets in ovarian cancer.link_to_OA_fulltextThe 101st Annual Meeting of the American Association for Cancer Research (AACR 2010), Washington D.C., 17-21 April 2010

A novel and effective hepatocyte growth factor kringle 1 domain and p53 cocktail viral gene therapy for the treatment of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a leading cause of cancer death worldwide, yet effective therapeutic options for advanced HCC are limited. Kringle 1 domain of HGF (HGFK1) has been demonstrated as a potent anti-tumor molecule and p53 is a well established tumor suppressor. Recently we developed AAV transducing HGFK1 (AAV-HGFK1) as a gene therapy for HCC. Here we investigated the possibility of enhancing the effect of AAV-HGFK1 by combining it with Adv transducing p53 (Adv-p53). In vitro expression experiments suggested a small amount of Adv-p53 could increase the expression of AAV transgenes. AAV-HGFK1 + Adv-p53 cocktail strongly inhibited the proliferation of microvascular endothelial cell (MEC) and two HCC cell lines, Hepa1-6 and McA-RH7777. In two orthotopic mice and rat HCC models the cocktail gene therapy also significantly reduced the tumor burdens and prolonged the survival time by inhibiting tumor angiogenesis and inducing tumor cell death. Significantly, tumor metastasis was completely prevented. AAV-HGFK1 + Adv-p53 viral cocktail may be a promising cancer therapy for the treatment of HCC. © 2008 Elsevier Ireland Ltd. All rights reserved.link_to_subscribed_fulltex

Downregulation of ASPP2 in choriocarcinoma contributes to increased migratory potential through Src activation

Poster Session 7 - Signaling Pathways Involved in Oncogenesis and Tumor Suppression: abstract no. 2107Gestational choriocarcinoma is a malignant tumour derived from placental trophoblast and is the most aggressive member of gestational trophoblastic disease (GTD). Apoptotic stimulating protein of p53-2 (ASPP2) is a tumor suppressor member of the ASPP family which transactivates p53-dependent apoptotic pathway. In this study, we examined the expression profile of ASPP2 in choriocarcinoma in comparison with normal placentas and hydatidiform moles which is a type of GTD that carries malignant potential. Results from quantitative PCR and immunohistochemical studies showed that downregulation of ASPP2 was detected in ...link_to_OA_fulltextThe 102nd Annual Meeting of the American Association for Cancer Research (AACR 2011), Orlando, FL., 2-6 April 2011