Presenting Author Indian Institute of Science Education and Research, Kolkata Nadia, India
Ovarian cancer is the 7th most common cancer of women and the most lethal gynecological cancer that demands rigorous treatments involving increased radiation cycles and higher drug concentration that triggers toxicity and eventually mortality of patients. Understanding of the diseases progression warrants effective therapeutic inventions. Epithelial Ovarian Cancer cell lines ID8 derived from C57Bl/6 mice and ID8 transfected with Vascular Endothelial Growth Factor-A (ID8-VEGF) were used in vitro to generate a Syngeneic Ovarian Cancer Mouse Model. Vascular Endothelial Growth Factor-A (VEGF-A/VEGF) is the critical regulator of tumor angiogenesis that supports the transport of nutrients, hormones and O2 to the tumor cells and removal of waste products and CO2. It regulates vascular permeability, actin reorganization, cell migration, enhances tumor growth and progression, which may be associated with aberrant cellular metabolism due to altered gap junction intercellular communication (GJIC) contributing to the tumorigenesis. The transmembrane protein Connexin forms hexameric hemichannels known as connexons and docks with another connexon of adjacent cells to form a functional GJIC. Connexin 43 (Cx43) is one of the most ubiquitously expressed connexins and its C-terminus interacts with various molecules to regulate many biological functions, including modulation of hemichannel activity, apoptotic signaling, cell cycle regulation and, cytoskeletal rearrangements. Our study aims to understand the effect of VEGF expression on the spatial expression of Cx43 and its nexus with other cellular factors contributing to consequent GJIC formation in the ovarian cancer cells as well as in the mouse model. Our findings suggest that upregulation of VEGF in ID8-VEGF cell lines is associated with accelerated tumor formation in syngeneic mouse models. A series of biochemical and cellular studies revealed that Sodium Phenylbutyrate(4PBA) treatment induced differential upregulation of Cx43 trafficking to the cell surface, rearrangement of cytoskeletal proteins, cell migration, and the formation of GJIC in ID8 and ID8-VEGF cells. 4PBA treatment on ID8-VEGF cells significantly reduced the rate of tumor formation. These differential cellular activities denote that VEGF may directly or indirectly interact with cytoskeletal proteins that regulate Cx43 trafficking and its GJIC formation. Overall, The increased capacity of GJIC formation post-4PBA treatment is associated with reduction in cell migration in vitro (ID8 and ID8-VEGF) and tumor formation in vivo (ID8-VEGF). Interactome studies combining RNASeq and IPA are designed to understand the nexus between several cellular pathways, including oxidative stress in the regulation of Cx43 in the context of VEGF, to dissect the cellular and molecular mechanism of metastasis.
Project is funded by Department of Biotechnology, India (BT/MED II/NIBMG/SYMEC/2014/Vol.II) and VM is supported by Prime Ministers Research Fellowship.
