Abstract 1204: MET receptor as a key player responsible for malignant properties and intracellular trafficking and fate of CXCR4 in cervical carcinoma cells
Authors: Katarzyna Miekus, Marta Pawlowska, Małgorzata Sekula, Estanis Navarro, Ewa Wybieralska, Zbigniew Madeja, Isabel Fabregat, Marcin Majka
Journal: Cancer Research (2012)

Abstract Introduction Cervical carcinoma (CC) is one of the major causes of death among women suffering from tumor especially in low and middle income countries. MET activation is crucial in epithelial EMT, cell motility and invasiveness under both normal and pathological conditions. Another family of receptors that play a critical role in tumor initiation, promotion and progression are chemokine receptors. One of the best studied is a seven - span transmembrane G - protein coupled receptor, CXCR4. CXCR4 promotes metastasis of tumor cells and its blockade inhibits tumor growth. Recently we have shown that HGF/MET axis synergizes with SDF-1/CXCR4 axis in stimulating CC cell chemotaxis and activation of various intracellular pathways. Aim The aim of the study was to evaluate the influence of MET receptor downregulation on cervical carcinoma cells. Materials and methods HTB-35 CC cell line was transduced with MET and LacZ shRNA expressing virus. Morphometry was performed with Nomarski interference contrast optics and MIGRA software. F-actin organization was evaluated using falloidin staining. The level of various genes expression was estimated by real-time RT-PCR Cells were transfected by EGFP-CXCR4 plasmid using lipofectamine and intracellular trafficking of CXCR4 was studied by immunofluorescence staining with confocal microscopy. Results MET receptor downregulation changes the morphology of HTB35 shMET cell line. Cells became smaller than wild type and shLacZ cells. Moreover, F-actin was located under cells membrane and it did not form regular stress fibers as they were observed in control cells. Downregulation of MET receptor influences changes in gene expression responsible for invasive phenotype and EMT. We have observed downregulation of CXCR4 and Slug and upregulation of E-cadherin. In trafficking studies we have observed different localization and polarization of CXCR4 receptor. In MET deficient cells CXCR4 was partially located in Golgi but it did not colocalize with AP1 and Sec-8 protein in exocytosis process. We have not observed recycling back of the CXCR4 receptor with AP2 staining in MET deficient HTB-35 cells. Conclusions The downregulation of MET receptor expression is responsible for a change in the expression of genes correlated with malignant phenotype and involved in EMT of CC cells. The downregulation of MET expression is responsible for more epithelial phenotype of HTB-35 cells. MET receptor downregulation influences intracellular trafficking of CXCR4 what might have a significant clinical implication for the treatment of tumor cells. Acknowledgement This study was supported by research grant from the Polish Ministry of Science and Higher Education NN 401142339, NN 401054839, NN 401010036, grant from Jagiellonian University Collegium Medicum: K/ZDS/002279 and EMBO short term fellowship ASTF 97-2010 Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1204. doi:1538-7445.AM2012-1204