Wnt/β-catenin pathway as a potential prognostic and predictive marker in patients with advanced ovarian cancer

Discovery of candidate tumor biomarkers for treatment with intraperitoneal chemotherapy for ovarian cancer

Tumor mRNA expression was used to discover genes associated with worse survival or no survival benefit after intraperitoneal (IP) chemotherapy. Data for high grade serous ovarian cancer patients treated with IP (n = 90) or IV-only (n =  398) chemotherapy was obtained from The Cancer Genome Atlas. Progression free survival (PFS) and overall survival (OS) were compared between IP and IV groups using Kaplan-Meier analysis and Cox regression. Validations were performed by analyses of microarray and RNA-Seq mRNA expression data. PFS and OS were compared between IP and IV groups by permutation testing stratified by gene expression. P-values are two-tailed. IP chemotherapy increased PFS (26.7 vs 16.0 months, HR 0.43 (0.28-0.66), p = 0.0001) and OS (49.6 vs 38.2 months, HR 0.46 (0.25-0.83), p = 0.01). Increased expression of NCAM2 and TSHR and decreased expression of GCNT1 was associated with decreased PFS and OS after IV chemotherapy (p < 0.05). High tumor expression of LMAN2, FZD4, FZD5, or STT3A was associated with no significant PFS increase after IP compared to IV chemotherapy. Low expression of APC2 and high expression of FUT9 was associated with 5.5 and 7.2 months, respectively, decreased OS after IP compared to IV chemotherapy (p ≤ 0.007).

The role of reproductive hormones in epithelial ovarian carcinogenesis

Epithelial ovarian cancer comprises ∼85% of all ovarian cancer cases. Despite acceptance regarding the influence of reproductive hormones on ovarian cancer risk and considerable advances in the understanding of epithelial ovarian carcinogenesis on a molecular level, complete understanding of the biologic processes underlying malignant transformation of ovarian surface epithelium is lacking. Various hypotheses have been proposed over the past several decades to explain the etiology of the disease. The role of reproductive hormones in epithelial ovarian carcinogenesis remains a key topic of research. Primary questions in the field of ovarian cancer biology center on its developmental cell of origin, the positive and negative effects of each class of hormones on ovarian cancer initiation and progression, and the role of the immune system in the ovarian cancer microenvironment. The development of the female reproductive tract is dictated by the hormonal milieu during embryogenesis. Intensive research efforts have revealed that ovarian cancer is a heterogenous disease that may develop from multiple extra-ovarian tissues, including both Müllerian (fallopian tubes, endometrium) and non-Müllerian structures (gastrointestinal tissue), contributing to its heterogeneity and distinct histologic subtypes. The mechanism underlying ovarian localization, however, remains unclear. Here, we discuss the role of reproductive hormones in influencing the immune system and tipping the balance against or in favor of developing ovarian cancer. We comment on animal models that are critical for experimentally validating existing hypotheses in key areas of endocrine research and useful for preclinical drug development. Finally, we address emerging therapeutic trends directed against ovarian cancer.

Elevated β-catenin activity contributes to carboplatin resistance in A2780cp ovarian cancer cells

Ovarian cancer is the fifth leading cause of cancer-related mortalities in women. Epithelial ovarian cancer (EOC) represents approximately 90% of all ovarian malignancies. Most EOC patients are diagnosed at advanced stages and current chemotherapy regimens are ineffective against advanced EOC due to the development of chemoresistance. It is important to better understand the molecular mechanisms underlying acquired resistance to effectively manage this disease. In this study, we examined the expression of the Wnt/β-catenin signaling components in the paired cisplatin-sensitive (A2780s) and cisplatin-resistant (A2780cp) EOC cell lines. Our results showed that several negative regulators of Wnt signaling are downregulated, whereas a few Wnt ligands and known Wnt/β-catenin target genes are upregulated in A2780cp cells compared to A2780s cells, suggesting that Wnt/β-catenin signaling is more active in A2780cp cells. Further analysis revealed nuclear localization of β-catenin and higher β-catenin transcriptional activity in A2780cp cells compared to A2780s cells. Finally, we demonstrated that chemical inhibition of β-catenin transcriptional activity by its inhibitor CCT036477 sensitized A2780cp cells to carboplatin, supporting a role for β-catenin in carboplatin resistance in A2780cp cells. In conclusion, our data suggest that increased Wnt/β-catenin signaling activity contributes to carboplatin resistance in A2780cp cells.

Wnt signalling in gynaecological cancers: A future target for personalised medicine?

The three major gynaecological cancers, ovarian, uterine and cervical, contribute a significant burden to global cancer mortality, and affect women in both developed and developing countries. However, unlike other cancer types that have seen rapid advances and incorporation of targeted treatments in recent years, personalised medicine is not yet a reality in the treatment of gynaecological cancers. Advances in sequencing technology and international collaborations and initiatives such as The Cancer Genome Atlas are now revealing the molecular basis of these cancers, and highlighting key signalling pathways involved. One pathway which plays a role in all three cancer types, is the Wnt signalling pathway. This complex developmental pathway is altered in most human malignancies, and members of this pathway, particularly the recently linked ROR receptor tyrosine kinases may be attractive future therapeutic targets. This review provides an up-to-date summary of research into Wnt signalling and ovarian, uterine and cervical cancers, and discusses the potential of the Wnt pathway as a future target for personalised medicine in gynaecological cancers.

TMPyP4-regulated cell proliferation and apoptosis through the Wnt/β-catenin signaling pathway in SW480 cells

BACKGROUND

The aim of this study was to investigate the potential effects of the 5, 10, 15, 20-tetrakis (1-methylpyridinium-4-yl) porphyrin (TMPyP4) on the proliferation and apoptosis of SW480 cells and the underlying mechanisms by which TMPyP4 exerted its actions.

METHODS

After treated with different doses of TMPyP4, cell viability was determined by MTT method, the apoptosis was observed by flow cytometry (FCM) and the expression of Wnt, GSK-3β, β-catenin and cyclinD1 was measured by RT-PCR and Western blot analysis.

RESULTS

The analysis revealed that TMPyP4 potently suppressed cell viability and induced the apoptosis of SW480 cells in a dose-dependent manner. In addition, the downregulation of Wnt, β-catenin and cyclinD1 expression levels was detected in TMPyP4-treated SW480 cells. However, followed by the block of Wnt signaling pathway using siRNA methods, the effects of TMPyP4 on proliferation and apoptosis of SW480 cells were significantly reduced.

CONCLUSION

It indicates that the TMPyP4-inhibited proliferation and -induced apoptosis in SW480 cells was accompanied by the suppression of Wnt/β-catenin signaling pathway. Therefore, TMPyP4 may represent a potential therapeutic method for the treatment of colon carcinoma.

Hormone receptor, HER2/NEU and EGFR expression in ovarian carcinoma--is here a prognostic phenotype?

PURPOSE

We aimed to evaluate the effects of hormone receptor, HER2, and epidermal growth factor receptor (EGFR) expression on epithelial ovarian cancer (EOC) prognosis and investigate whether or not phenotypic subtypes might exist.

MATERIALS AND METHODS

The medical records of 82 patients who were diagnosed with EOC between 2003 and 2012 and treated by platinum-based chemotherapy were retrospectively evaluated. Expression of EGFR, oestrogen (ER), progesterone (PR), and cerbB2 (HER2) receptors were assessed immunohistochemically on paraffin-embedded tissues of these patients. Three phenotypic subtypes were defined according to ER, PR, and HER2 expression and associations of these with EGFR expression, clinicopathologic features, platinum sensitivity, and survival were investigated.

RESULTS

When we classified EOC patients into three subtypes, 63.4% had hormone receptor positive (HR(+)) (considering breast cancer subtypes, luminal A), 18.3% had triple negative, and 18.3% had HER2(+) disease. EGFR positivity was observed in 37 patients (45.1%) and was significantly more frequent with advanced disease (p=0.013). However, no significant association with other clinicopathologic features and platinum sensitivity was observed. HER2(+) patients had significantly poorer outcomes than HER2(-) counterparts (triple negative and HR positive patients) (p=0.019). Multivariate analysis demonstrated that the strongest risk factor for death was residual disease after primary surgery.

CONCLUSIONS

Triple negative EOC may not be an aggressive phenotype as in breast cancer. The HER2 positive EOC has more aggressive behaviour compared to triple negative and HR(+) phenotypes. EGFR expression is more frequent in advanced tumours, but is not related with poorer outcome. Additional ovarian cancer molecular subtyping using gene expression analysis may provide more reliable data.

Inhibition of STAT3 signaling as critical molecular event in resveratrol-suppressed ovarian cancer cells

Background

Resveratrol exerts inhibitory effects on ovarian cancer cells, while its underlying mechanism and critical molecular target(s) have been lesser known. Activations of Wnt, Notch and STAT3 signaling are frequent in ovarian cancers/OCs and supposed to be important for OC formation and progression, while the impacts of resveratrol on these signaling pathways in OC cells remain obscure.

Methods

In this study, two human ovarian cancer cell lines, OVCAR-3 and CAOV-3, were treated by 120 μM resveratrol and their responses to the treatment and the statuses of Wnt, Notch and STAT3 signaling in them were analyzed by multiple experimental approaches. Selective inhibitors of Wnt, Notch or STAT3 signaling were employed to treat OVCAR-3 and CAOV-3 cells to elucidate the significance of individual signaling pathways for ovarian cancers.

Results

The results demonstrated distinct inhibitory effects of resveratrol on human ovarian cancer cells in terms of remarkable G1 phase accumulation, increased apoptosis fraction and concurrent suppression of Wnt, Notch and STAT3 signaling as well as their downstream cancer-related gene expression. Treatments with Wnt, Notch or STAT3 selective inhibitor revealed that only AG490, a JAK-specific inhibitor, inhibits OVCAR-3 and CAOV-3 cells in the extent as similar as that of resveratrol.

Conclusion

Our results suggest the significance of STAT3 activation in the maintenance and survival of ovarian cancer cells. The activated STAT3 signaling is the critical molecular target of resveratrol. Resveratrol would be a promising candidate in the management of ovarian cancers, especially the ones with resistance to conventional therapeutic agents.

β-Catenin expression is regulated by an IRES-dependent mechanism and stimulated by paclitaxel in human ovarian cancer cells

Paclitaxel (PTX) is commonly used in the chemotherapy of ovarian cancer, but resistance occurs in most cases, allowing cancer progression. The Wnt/β-catenin pathway has been associated with this resistance, but there are no reports on the regulation of β-catenin expression at the translational level. In the present study, we found that PTX induced different transcription and translation levels of β-catenin in the human ovarian cancer cell lines A2780 and SKOV3. We also demonstrated that β-catenin mRNA contained an internal ribosome entry segment (IRES) that regulated its translation. Using gene transfection and reporter assays, we revealed that the entire CTNNB1 5'-untranslated region (UTR) contributed to IRES activity. Interestingly, we found that c-myc and cyclin D1 increased significantly in transfected cells with increasing PTX concentration, and cell-survival rates remained at 60% while the PTX concentration increased. Suppressing β-catenin resulted in decreased expression of c-myc and cyclin D1 and made these cells less resistant. These results indicate that β-catenin translation is initiated via the IRES and this is regulated by PTX, suggesting that regulation of the IRES-dependent translation of β-catenin may be involved in the cancer cell response to PTX treatment.

Interference with the expression of β-catenin reverses cisplatin resistance in A2780/DDP cells and inhibits the progression of ovarian cancer in mouse model

Cisplatin is a most active drug for the treatment of ovarian cancer; however, acquired cisplatin resistance is easily seen in patients with ovarian cancer. The aim of this study is to clarify the molecular mechanism of cisplatin resistance and try to reverse cisplatin resistance in ovarian cancer lines in vitro and in vivo. First, we used ovarian cancer cell line A2780, and its cisplatin-resistant subline, A2780/DDP as cell model. Cell viability was determined by MTT assay and the IC50 values were observed to increase in a dose- and time-dependent manner. Next, the expression of β-catenin was determined by western blotting analysis, and the results demonstrated that the expression level of β-catenin in A2780/DDP cells was significantly higher than that in A2780 cells (p<0.01). Moreover, we detected the distribution of cytoplasmic and nuclear β-catenin by western blot analysis, which showed that β-catenin was mainly located in nucleus. Compared with A2780 cells, there was no obvious change as the increasing dose of cisplatin in A2780/DDP cells reveal that cisplatin resistance was related to the exrpession of β-catenin. Furthermore, interference with the expression of β-catenin could effectively reverse cisplatin resistance as IC50 was significantly decreased from 123.7 to 42.43 μM in A2780/DDP cells. Additionally, transient interference of β-catenin by siRNA promoted the apoptosis of A2780/DDP cells, for increased apoptosis rates and cleaved caspase-3 levels were detected being treated with cisplatin. Finally, tumorigenicity experiments showed that tumor growth was significantly suppressed in β-catenin shRNA group. The body weight was not significantly changed during the experimental days. In conclusion, all the results showed that cisplatin resistance was partly induced by Wnt/β-catenin signaling pathway. Interfering the expression of β-catenin could reverse cisplatin resistance in vitro and in vivo. Thus, β-catenin could be a potential therapeutic target for the therapy of cisplatin-resistant ovarian cancer.

Inhibition of ovarian cancer proliferation and invasion by pachymic acid

To determine the effect of pachymic acid (PA) on proliferation, cell cycle, and invasion in human ovarian carcinoma cell lines HO-8910 and explore some possible mechanisms, HO-8910 cells was treated with different concentrations of PA (0.5, 1, 2 μM). CCK-8 assay, propidium iodide staining, was applied to measuring the growth inhibiting rates of HO-8910 cells. Cell cycle was measured by flow cytometry. In addition, the activity of PA against HO-8910 cells invasion was evaluated in transwell assay. Western blot detected the proteins expression of E-cadherin, β-catenin and COX-2 of different groups treated with PA in different concentrations (0.5, 1, 2 μM) for 48 h. Our results showed that PA could effectively inhibit the in vitro growth of HO-8910 cells in dose-dependent manners in 72 h, suppressed migration and invasion of HO-8910 cells in concentration-dependent manners at 24 h, caused the increased accumulation of G1 phase cells, and caused down-regulation of β-catenin and COX-2 and up-regulation of E-cadherin expression level. Taken together, it could conclude that PA might inhibit proliferation and invasion of ovarian carcinoma cell through decreasing β-catenin and COX-2 expression and increasing E-cadherin expression.

PROGgeneV2: enhancements on the existing database

Background

We recently published PROGgene, a tool that can be used to study prognostic implications of genes in various cancers. The first version of the tool had several areas for improvement. In this paper we present some major enhancements we have made on the existing tool in the new version, PROGgeneV2.

Results

In PROGgeneV2, we have made several modifications to enhance survival analysis capability of the tool. First, we have increased the repository of public studies catalogued in our tool by almost two folds. We have also added additional functionalities to perform survival analysis in a variety of new ways. Survival analysis can now be performed on a) single genes b) multiple genes as a signature, c) ratio of expression of two genes, and d) curated/published gene signatures in new version. Users can now also adjust the survival analysis models for available covariates. Users can study prognostic implications of entire gene signatures in different cancer types, which are searchable by keywords. Also, unique to our tool, in the new version, users will be able to upload and use their own datasets to perform survival analysis on genes of interest.

Conclusions

We believe, like its predecessor, PROGGeneV2 will continue to be useful for the scientific community for formulating research hypotheses and designing mechanistic studies. With added datasets PROGgeneV2 is the most comprehensive survival analysis tool available. PROGgeneV2 is available at http://www.compbio.iupui.edu/proggene.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2407-14-970) contains supplementary material, which is available to authorized users.

TP53 oncomorphic mutations predict resistance to platinum‑ and taxane‑based standard chemotherapy in patients diagnosed with advanced serous ovarian carcinoma

Individual mutations in the tumor suppressor TP53 alter p53 protein function. Some mutations create a non-functional protein, whereas others confer oncogenic activity, which we term ‘oncomorphic’. Since mutations in TP53 occur in nearly all ovarian tumors, the objective of this study was to determine the relationship of oncomorphic TP53 mutations with patient outcomes in advanced serous ovarian cancer patients. Clinical and molecular data from 264 high-grade serous ovarian cancer patients uniformly treated with standard platinum- and taxane-based adjuvant chemotherapy were downloaded from The Cancer Genome Atlas (TCGA) portal. Additionally, patient samples were obtained from the University of Iowa and individual mutations were analyzed in ovarian cancer cell lines. Mutations in the TP53 were annotated and categorized as oncomorphic, loss of function (LOF), or unclassified. Associations between mutation types, chemoresistance, recurrence, and progression-free survival (PFS) were calculated. Oncomorphic TP53 mutations were present in 21.3% of ovarian cancers in the TCGA dataset. Patients with oncomorphic TP53 mutations demonstrated significantly worse PFS, a 60% higher risk of recurrence (HR=1.60, 95% confidence intervals 1.09, 2.33, p=0.015), and higher rates of platinum resistance (χ² test p=0.0024) when compared with single nucleotide mutations not categorized as oncomorphic. Furthermore, tumors containing oncomorphic TP53 mutations displayed unique protein expression profiles, and some mutations conferred increased clonogenic capacity in ovarian cancer cell models. Our study reveals that oncomorphic TP53 mutations are associated with worse patient outcome. These data suggest that future studies should take into consideration the functional consequences of TP53 mutations when determining treatment options.

Role of epithelial to mesenchymal transition proteins in gynecological cancers: pathological and therapeutic perspectives

Gynecorelogic cancers like ovarian, cervical, and endometrial cancers are among the major threats to modern life, especially to female health. Like some other types of cancers, all of these gynecological cancers have found to be associated with the developmental stage epithelial to mesenchymal transition (EMT). More specifically, the aberrant expression of major EMT markers, such as lower expressions of E-cadherin and alpha-catenin, and overexpressions of N-cadherin, beta-catenin, vimentin, and matrix metalloproteinases, have been reported in ovarian, cervical, and endometrial cancers. The transcription factors, such as Twist, Snail, Slug, and Zeb, which regulate these EMT mediators, are also reported to be overexpressed in gynecological cancers. In addition to the over/lower expression, the promoter methylation of some of these genes has been identified too. In the era of target-specific cancer therapeutics, some promising studies showed that targeting EMT markers might be an interesting and successful tool in future cancer therapy. In this study, we have reviewed the recent development in the research on the association of EMT markers with three major gynecological cancers in the perspectives of carcinogenesis and therapeutics.

Correlation Between E-cadherin Immunoexpression and Efficacy of First Line Platinum-Based Chemotherapy in Advanced High Grade Serous Ovarian Cancer

To analyze correlation between immunoexpression of E-cadherin and efficacy of first line platinum-based chemotherapy in patients with advanced-stage high-grade serous ovarian carcinoma. The expression of E-cadherin was analyzed immunohistochemically in formalin-fixed, paraffin-embedded samples from 98 patients with advanced-stage high-grade serous ovarian cancer and related to clinical features (stage according to the International Federation of Gynecology and Obstetrics (FIGO) and residual tumors after initial cytoreductive surgery), response to platinum-based chemotherapy (according to Response Evaluation Criteria in Solid tumors (RECIST 1.1 criteria)), platinum sensitivity (according to platinum free interval (PFI) as platinum-refractory, platinum-resistant and platinum-sensitive) and patients progression free survival (PFS) and overall survival (OS). E-cadherin immunostaining was positive in 74 and negative in 24 serous ovarian carcinomas. E-cadherin immunoreactivity was not associated with FIGO stage, residual tumor after initial cytoreductive surgery and number of chemotherapy cycles. Positive E-cadherin expression predict significantly better response to first line platinum-based chemotherapy (p < 0.001) and platinum sensitivity (p < 0.001). Moreover, positive E-cadherin expression predict significantly longer PFS (p < 0.001) and OS (p < 0.001). The multivariate analysis for OS showed that positive E-cadherin expression is predictor to platinum sensitivity (p < 0.001) and longer OS (p = 0.01). Positive E-cadherin expression seems to be a predictor of better response to first line platinum-based chemotherapy, platinum sensitivity and favorable clinical outcome in patients with advanced-stage serous ovarian cancer. Negative E-cadherin expression was shown to be significant, independent predictor of poorer PFS and OS. E-cadherin as a marker has predictive and prognostic value.