Evaluate the Radio-Biological Roles of miR-17-5P in Oral Cancer Cell Line OC3

Betel nut chewing is associated with oral cavity cancer in Taiwan. Radiotherapy is one of the therapeutic approaches. miR-17-92 polycistronic miRNA is the first cluster of miRNA that be found to involve in cancer cell anti-apoptosis capability. A single miRNA may repress the production of hundreds of proteins. Recently, we used a cancer cell line OC3, (which is established from an oral squamous cell carcinoma in a long-term betel nut chewer who does not smoke), to investigate the expression and the role of miR-17-92 polycistronic miRNA in irradiated oral carcinoma cell. The result revealed that miR-17-5p is enhanced in irradiated OC3 cells, miR-17-5p was also found to inhibit its downstream protein p21 expression, since p21 plays critical role in the rediosensitivity of OC3, the effect of radiation induced miR-17-5p expression imply the molecular mechanism of radio-resistance of OC3 cells. The role of miR-17-5p/p21 was confirmed in in vitro and in vivo models, and this study has been published in Strahlenther Onkol. 2013 Aug;189(8):675-83。 In this two years project, we will follow this model and globally investigate the biological roles of miR-17-5p in irradiated OC3 cells. The aim of each year is: In the first year: To screen out the miR-17-5p mediated specific protein expression by proteomics. The study strategies and major methodologies are: 1. Analysis and comparison the protein expression patterns in the control and miR-17-5p over-expressed OC3 cells by proteomics. 2. Identify 200 proteins that are different expressed between control and miR-17-5p over-expressed OC3 cells with GC-MASS. 3. Clarify the roles and relations among the 200 proteins by the Systems biology analysis. 4. Confirm the expression of 10% specific proteins that predicted by the systems biology with western blot. In the second year: To clarify the biological roles of certain protein that identified in the first year by molecular cell biology and animal study, we will focus on the radiotherapy related anti-apoptosis, angiogenesis and inflammatory cytokines. The study strategies and major methodologies are: 1. To determine the expression of specific proteins that identified from proteomics on the irradiated OC3 xenograft tumors section by Immunohistochemistry(IHC). 2. To clarify the anti-apoptosis role of certain proteins that regulated by miR-17-5p with siRNA to inhibit its expression and to confirm its role by Annexin-V staining, cell cycle analysis, Hochese based aopototic bodies staining and DNA laddering assay. 3. To clarify the angiogenesis role of certain proteins that regulated by miR-17-5p with siRNA to inhibit its expression and to confirm its role by endothelial cells with permeability assay, cell growth assay, tube formation assay and cell migration assays. 4. To clarify the chemotaxis role of certain proteins that regulated by miR-17-5p with siRNA to inhibit its expression and to confirm its role by monocytes chemotaxis assay. 5. To identify the clinical significance of miR-17-5p in oral cancer by determining the expression of miR-17-5p regulated proteins by IHC with the commercialized oral cancer tissue array. We expect the results from this study may provide complete information that from basic study to clinical significance of miR-17-5p regulated biological roles in oral cancer radio-biology.