MMPs in Ovarian Cancer as Therapeutic Targets
In the United States, about 22,000 women will be diagnosed with ovarian cancer in 2011, and an estimated 14,000 patients will succumb to the disease . Surgery and chemotherapy present the main treatment modalities, but despite the development of novel therapies, the overall 5 years survival for ovarian cancer patients with advanced disease at diagnosis remains at only about 30%. Novel therapeutic strategies are needed to prolong survival and achieve greater cure rates. Matrix metalloproteinases (MMPs) are frequently expressed in ovarian cancer, and play an important role in the metastatic process. MMPs mediate degradation of the basement membrane as a crucial step in epithelial transformation, ovarian tumorigenesis and intraperitoneal metastasis . Various preclinical and clinical studies have demonstrated that MMPs might provide a suitable therapeutic target. This review summarizes important observations regarding the expression of MMPs in ovarian cancer, their biological role, and data from clinical trials targeting MMPs in ovarian cancer patients.
Available from: erc.endocrinology-journals.org
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ABSTRACT: Phosphatidylinositol 3-kinase/AKT/mammalian target of rapamycin pathway plays a key role in the tumorigenesis of a variety of human cancers including ovarian cancer. However, inhibitors of this pathway such as Rad001 have not shown therapeutic efficacy as a single agent for this cancer. Arsenic trioxide (ATO) induces an autophagic pathway in ovarian carcinoma cells. We found that ATO can synergize with Rad001 to induce cytotoxicity of ovarian cancer cells. Moreover, we identified synergistic induction of autophagy and apoptosis as the likely underlying mechanism that is responsible for the enhanced cytotoxicity. The enhanced cytotoxicity is accompanied by decreased p-AKT levels as well as upregulation of ATG5-ATG12 conjugate and LC3-2, hallmarks of autophagy. Rad001 and ATO can also synergistically inhibit tumors in a xenograft animal model of ovarian cancer. These results thus identify and validate a novel mechanism to enhance and expand the existing targeted therapeutic agent to treat human ovarian cancer.
Available from: Xuan Bich Trinh
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ABSTRACT: Previously, we have identified the RUNX1 gene as hypomethylated and overexpressed in post-chemotherapy (CT) primary cultures derived from epithelial ovarian cancer (EOC) patients, when compared with primary cultures derived from matched primary (prior to CT) tumors. Here we show that RUNX1 displays a trend of hypomethylation, although not significant, in omental metastases compared with primary EOC tumors. Surprisingly, RUNX1 displayed significantly higher expression not only in metastatic tissue, but also in high-grade primary tumors and even in low malignant potential tumors. The RUNX1 expression levels were almost identical in primary tumors and omental metastases, suggesting that RUNX1 hypomethylation might have a limited impact on its overexpression in advanced (metastatic) stage of the disease. Knockdown of the RUNX1 expression in EOC cells led to sharp decrease of cell proliferation and induced G 1 cell cycle arrest. Moreover, RUNX1 suppression significantly inhibited EOC cell migration and invasion. Gene expression profiling and consecutive network and pathway analyses confirmed these findings, as numerous genes and pathways known previously to be implicated in ovarian tumorigenesis, including EOC tumor invasion and metastasis, were found to be downregulated upon RUNX1 suppression, while a number of pro-apoptotic genes and some EOC tumor suppressor genes were induced. Taken together, our data are indicative for a strong oncogenic potential of the RUNX1 gene in EOC progression and suggest that RUNX1 might be a novel EOC therapeutic target. Further studies are needed to more completely elucidate the functional implications of RUNX1 and other members of the RUNX gene family in ovarian tumorigenesis.
Available from: Tobias Meckel
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ABSTRACT: Modern cancer research requires physiological, three-dimensional (3D) cell culture platforms, wherein the physical and chemical characteristics of the extracellular matrix (ECM) can be modified. In this study, gelatine methacrylamide-based hydrogels (GelMA) were characterised and established as in vitro and in vivo spheroid-based models for ovarian cancer, reflecting the advanced disease stage of patients, with accumulation of multicellular spheroids in the tumour fluid (ascites).
Polymer concentration (2.5-7% w/v) strongly influenced hydrogel stiffness (0.5 ± 0.2 kPa – 9.0 ± 1.8 kPa) but had little effect on solute diffusion. The diffusion coefficient of 70 kDa FITC-labelled dextran in 7% GelMA-based hydrogels was only 2.3-times slower compared to water. Hydrogels of medium concentration (5% w/v GelMA) and stiffness (3.4 kPa) allowed spheroid formation and high proliferation and metabolic rates. The inhibition of matrix metalloproteinases and consequently ECM degradability reduced spheroid formation and proliferation rates. The incorporation of the ECM components laminin-411 and hyaluronic acid further stimulated spheroid growth within GelMA-based hydrogels. The feasibility of pre-cultured GelMA-based hydrogels as spheroid carriers within an ovarian cancer animal model was proven and led to tumour development and metastasis. These tumours were sensitive to treatment with the anti-cancer drug paclitaxel, but not the integrin antagonist ATN-161. While paclitaxel and its combination with ATN-161 resulted in a treatment response of 33-37.8%, ATN-161 alone had no effect on tumour growth and peritoneal spread.
The semi-synthetic biomaterial GelMA combines relevant natural cues with tunable properties providing an alternative, bioengineered 3D cancer cell culture in vitro and in vivo model system.
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