FLOT1 is associated with HGF mediated cell invasion and proliferation by increased MMP9.

The flotillin protein family, including flotillin-1 (FLOT1 ) and flotillin-2 (FLOT2), have been known as markers of lipid rafts. Recentely, FLOT1 was reported that FLOT1 overexpression was found in several advanced cancer including breast, colorectal, prostate tumors, and renal cell carcinomas and correlate with poor prognosis in advanced tumors. The purpose of this study is to identify the role of HGF upregulated FLOT1 associated with cancer cell proliferation and invasion in gastric cancer.

We used cell culture, western blotting, RT-PCR, MTT assays, CHIP assay, zymography and FLOT 1 knock-down with short hairpin RNA (shRNA).

First, we confirmed that the expression level of FLOT1 was up-regulated by HGF(hepatocyte growth factor). To determine the role for FLOT1, we used the knock down cell of FLOT1. FLOT1 -sh RNA cells showed a decreased level of MMP9 and NFkB. We also examined to confirm the role of HGF-mediated FLOT1. HGF-mediated cell proliferation and in vitro invasion was decreased in FLOT1 knock down cell. We perforomed the zymography to evaluate the activity of MMP9 . The activity of MMP9 was decreased in FLOT1 knock down cell. The level of AKT phosphorylation was decreased in the knock down cell of FLOT1. Also, We identified the putative binding site of NFkB in MMP9 promotor region and confirmed the function by CHIP assay.

Our study showed that upregulation FLOT1 by HGF increased the level of MMP9 through AKT/NFkB pathway and associated with cell proliferation and invasion in gastric cancer.

Key word : FLOT1, MMP9, NFkB, Gastric cancer