Presentation Abstract

Abstract Number: 4042
Presentation Title: MiR-200c sensitizes colorectal cancer cells to 5-FU through Bcl-2-involved apoptotic pathway
Presentation Time: Tuesday, Apr 20, 2010, 2:00 PM - 5:00 PM
Location: Exhibit Hall A-C, Poster Section 7
Poster Section: 7
Poster Board Number: 12
Author Block: Xuemin Qian, Paul Howell, Xiaobo Li, Xin Qin, Lin Gao, Yaguang Xi. Univ. of South Alabama Mitchell Cancer Inst., Mobile, AL
Abstract Body: Effective clinical management of colorectal cancer is still a major challenge in cancer care. MicroRNA is a set of newly-discovered, non-coding small RNA molecules that significantly contribute to a number of critical biological events including cell proliferation, apoptosis development, as well as tumorigenesis. Our group has previously identified a number of microRNA candidates associated with potential prognostic value in colorectal cancer patients. In this study, we investigated miR-200c and validated its impact on 5-FU chemosensitivity in colorectal cancer. Human colorectal cancer cell lines HCT116 and HCT15 were employed in this study. Pre-miR-200c precursor molecules and negative control (Ambion, Inc.) were transiently transfected into these cell lines and cell viability was examined using WST-1 assay (Roche, Inc.) after 5-FU treatment for 24 hours. The results indicate that miR-200c can potentially sensitize colorectal cancer cells to 5-FU up to 25% compared to controls. Also, cells over-expressing miR-200c have an approximately 50% higher apoptotic rate than controls based on flow cytometry results. Bioinformatics predicts Bcl-2 is a putative mRNA target of miR200c. Bcl-2 is an integral membrane protein located mainly on the outer membrane of mitochondria. Overexpression of Bcl-2 has been demonstrated to prevent cells from undergoing apoptosis in response to a variety of stimuli. In this study, we further experimentally validated the repressive abilities of miR-200c on Bcl-2 expression using Western Blot and Luciferase reporter assay. Our results demonstrates that miR-200c is a potential biomarker for predicting chemotherapeutic response in colorectal cancer and functions by repressing Bcl-2 expression and inducing apoptotic susceptibility to 5-FU. These results hold great promise for moving miRNAs toward future clinical application and contribute to the ultimate goal of developing or improving therapeutic intervention for patients with colorectal cancer.