Abstract 2306: MicroRNA 199a*: a potent suppressor of tumor metastasis and angiogenesis.

Abstract The growth of a solid tumor depends on diffusion of nutrients from the tumor microenvironment through vascular system. Angiogenesis, the new blood vessels formation is the primary route by which tumor cells get nutrients as well as exit from primary site and enter into the blood circulation. The proliferation and migration of vascular endothelial cells are triggered by angiogenic growth factors secreted by tumor cells, such as VEGF, TGF-β etc. Recent evidences showed HGF also plays an important role in angiogenesis by enhancing the proliferative activity and intracellular signaling. HGF/its receptor, c-MET and VEGF/VEGFR1 are two independent pathways for angiogenesis and metastasis. Thus detection of a molecule that hits both pathways could be a potent therapeutic agent that could facilitate the inhibition of improved barrier function. Recently mir199a* has been shown to target both CD44 and cMET molecule to block the metastasis in cancer. The present study aim to show that mir199a* also target HGF, the key modulator of the HGF/c-Met signaling cascade in epithelial cells to shut off the mesenchymal transition and VEGFR1 to prevent angiogenesis more effectively. Luciferase 3’ UTR assay was performed to investigate HGF as a target of mir-199a*. HGF mRNA and protein expression was determined by real time RT-PCR, Western blot analysis in liver stellate cell line LX2 transfected with mir-199a* and HGF shRNA. The cultured media of mir-199a* transfected LX2 cells was used to verify the effect of mir-199a* on HGF induced migration and invasion ability on metastatic cell lines using Boyden chamber assay with or without matrigel coated membrane and angiogenesis by tube formation assay. The mir-199a* binding site was detected by pictar, target scan analysis of the 3’UTR of HGF and VEGFRs. The binding of mir-199a* to the 3′UTR of HGF and VEGFR1 were confirmed by luciferase assay, mutagenesis and western blotting. Down regulation of HGF protein expression in HGF producing hepatic stellate cell, LX2 was observed by mir-199a*. Addition of LX2 conditioned media transfected with mir199a* to metastatic cell reduces the migration and invasion and also block angiogenesis in endothelial cells. As Mir-199a* could target HGF/cMET, CD44-cMET and VEGF/VEGFR1 signaling cascade, it could be used as a potential therapeutic target of HCC. Citation Format: Alip Ghosh, Amit Ghosh, Debanjali Dasgupta, Shrabasti Roychowdhury, Shrabasti Roychowdhury, Simanti Datta, Abhijit Chowdhury, Soma Banerjee. MicroRNA 199a*: a potent suppressor of tumor metastasis and angiogenesis. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 2306. doi:10.1158/1538-7445.AM2013-2306