The in vitro effects of caffeine on viability, cycle cycle profiles, proliferation, and apoptosis of glioblastomas.

OBJECTIVE We studied the effects of caffeine on cell viability, cell cycle profiles, proliferation, and apoptosis in rat C6 and human U87MG glioblastoma cell lines. MATERIALS AND METHODS Cell viability was quantified by the methyl thiazolyl tetrazolium (MTT) assay. Flow cytometry was used to quantify the relative number of cells in different phases of the cell cycle, while cell proliferation was quantified using the Cell Counting Kit-8. The proportion of apoptotic cells was determined by flow cytometry, and expression of apoptosis-related proteins Caspase-3, Cyt-C, Bax and Bcl-2 by Western blot. RESULTS Caffeine at doses of up to 0.5 mM did not affect cell viability in both rat C6 and human U87MG glioblastoma cells. Further studies were done using the dose of 0.5 mM. Percentage of cells in the G0/G1 phase was markedly increased, while percentage of cells in the S phase decreased, after cell treatment with caffeine. Cell proliferation was significantly inhibited by caffeine. Furthermore, caffeine induced cell apoptosis, decreased expression of Bcl-2, and increased expression of Cyt-C and Caspase-3. CONCLUSIONS Caffeine inhibits proliferation and induces apoptosis in glioblastoma cells. Our results provide the experimental basis for further studies of potential role of caffeine in the treatment of glioblastomas.