MicroRNA-17-5p expression in tumor tissue and serum of glioblastomas patients and function analysis of microRNA-17-5p on U87MG and U251 in vitro

Objective To study microRNA (miRNA, miR)-17-5p expression in the tumor tissue and serum of glioblastomas patients and the function of miR-17-5p on U87MG and U251 in vitro. Methods The miR-17-5p expression in the tumor tissue and serum of glioblastomas patients was detected by real-time quantitative reverse transcriptase-polymerase chain reaction (RT-qPCR). U87MG and U251 cells were treated with 20 μmol/L Cisplatin (DDP), 50 μmol/L Temozolomide or 30 Gy gamma ray irradiation and the expression level of miR-17-5p was evaluated. U87MG and U251 cells were transfected with miR-17-5p mimic and cultured in serum free medium to analyze the ability of miR-17-5p to promote cell survival. U87MG and U251 cells were transfected with miR-17-5p mimic, then the cell proliferation, cell migration, colony formation, and the protein expression levels of tumor protein p53 inducible nuclear protein 1 (TP53INP1), tripartite motif protein 8 (TRIM8) and zinc finger and BTB domain-containing protein 4 (ZBTB4) were evaluated. Results The miR-17-5p expression level in the tumor tissue (7.40±1.55) and serum (2.70±0.55) in glioblastomas patients was significantly elevated compared with tumor adjacent tissue and health human serum (P=0.019, P=0.028), and that in U87MG and U251 cells was increased after treatment with 20 μmol/L DDP, 50 μmol/L Temozolomide or 30 Gy gamma ray irradiation (P=0.001). MiR-17-5p could promote the survival of U87MG and U251 cells when cultured in serum free medium, at the same time, under the low serum condition [2.5% fatal bovine serun (FBS)], miR-17-5p could promote the cell migration[(20.50±2.33) mm and (14.50±1.35) mm] and colony formation [(225±45) cells and (312±58) cells] of U87MG and U251 cells, but in normal serum level (10% FBS), it could not promote the cell migration of U87MG and U251 cells, on the contrary, it could suppress the cell proliferation of U87MG and U251 cells. Western blotting results revealed that miR-17-5p could suppress the protein expression of tumor suppressor gene TP53INP1, TRIM8 and ZBTB4. Conclusion The expression level of miR-17-5p in the tumor tissue and serum of gliolbastomas patients was significantly upregulated. miR-17-5p could be used as a biomarker in glioblastomas detection. At the same time, miR-17-5p could promote the survival of U87MG and U251 cells under stress conditions. Key words: Gilobalstomas; MicroRNA-17-5p; U87MG; U251