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Abstract C28: MET receptor downregulation decreases oncogenic properties of cervical carcinoma cells in vitro and in vivo through E-cadherin re-expression and Slug downregulation

Introduction: Cervical carcinoma, despite the development of vaccine, is the second cause of death among women suffering from cancer, especially in low and middle incomes countries. There is currently no effective therapy for advanced cervical cancer and it is important to determine molecular markers, which can help to develop new therapeutic strategies. MET receptor plays an important role during embryonic development, wound healing as well as cancer development and progression. MET is overexpressed in a variety of human cancers increasing their aggressiveness by stimulating tumor cells proliferation, survival and motility. In cervical carcinoma, MET receptor has been shown i) to promote scattering and morphogenesis of tumor cells, ii) to regulate migration and cytoskeleton changes, iii) to translocate of B-catenin transcription factor into the nucleus and iv) to up-regulate cyclin D1 expression.

Objectives: In this study we asked whether downregulation of MET receptor changes cell phenotype into more benign and inhibits tumorigenesis of cervical cancer cells.

Materials and Methods: Cervical carcinoma cell line, HTB-35, was transduced with MET and LacZ shRNA expressing virus. The level of various genes expression was estimated by real-time RT-PCR. Protein expression was evaluated by Western blot. Immunofluorescence and immunohistochemistry staining was used to study the expression of E-cadherin in cells under culture condition and in paraffin tumor section. In in vivo study, cells were injected subcutaneously into NOD-SCID mice (5x106/mouse) and after 4 weeks, tumors were isolated, measured and weighted. All experiments were repeated at least 3 times. For the statistical analysis, P values were assessed with two-tailed Student's t test.

Results: In our study, we showed that silencing of MET receptor decreases proliferation rate by downregulation of cyclin D1 and c-myc. The growth rate between control and MET deficient cells differed significantly for each time point and, after 96 hours of culture, was three times higher for control cells. In MET deficient cells, the expression of cyclin D1 and c-myc was significantly lower in comparison to control cells at mRNA and protein level. Downregulation of MET receptor significantly decreases the expression of epithelial to mesenchymal transition regulating factor, Slug, and increases the expression of E-cadherin, a hallmark of epithelial phenotype in the in vitro study. We observed that downregulation of MET expression dramatically decreases tumor growth in NOD-SCID mice. HTB-35 control cells formed tumors of approximate weight of 1.7 g whereas MET deficient cells formed very small tumors with the mean weight of 0.08 g, or no tumors at all. Moreover, tumors formed by cells with MET receptor downregulation showed the expression of E-cadherin.

Summary: We show that MET receptor downregulation decreases oncogenic properties of cervical carcinoma cells in vitro and in vivo and changes cell phenotype into more epithelial and less aggressive. Thus, inhibition of HGF-MET receptor axis might help in the future to develop new treatment strategies to block cervical carcinoma development and progression.

Acknowledgement: This study was supported by research grants to K.M. from the Polish Ministry of Science and Higher Education NN 401142339, NN 401054839.

Citation Format: Katarzyna Miekus, Marta Pawlowska, Grazyna Drabik, Marcin Majka. MET receptor downregulation decreases oncogenic properties of cervical carcinoma cells in vitro and in vivo through E-cadherin re-expression and Slug downregulation. [abstract]. In: Proceedings of the Third AACR International Conference on Frontiers in Basic Cancer Research; Sep 18-22, 2013; National Harbor, MD. Philadelphia (PA): AACR; Cancer Res 2013;73(19 Suppl):Abstract nr C28.