Roscovitine has anti-proliferative and pro-apoptotic effects on glioblastoma cell lines: A pilot study

Abstract

Purine analogue roscovitine, a cyclin-dependent kinase (CDK) inhibitor, has shown strong anti-proliferative and pro-apoptotic effects in solid and hematologic cancers such as non small-cell lung cancer and lymphomas. It targets CDK2, 7 and 9 preferentially, which are also overexpressed in glioblastoma. Τherefore, the biological effects of roscovitine in glioblastoma cell lines were investigated. Glioblastoma A172 and G28 cell lines were incubated with serial concentrations of roscovitine for 24-120h. Proliferation was measured using the xCELLigence Real-Time Cell Analyzer, an impedance‑based cell viability system. Cell cycle distribution was assessed by flow cytometry and gene expression was quantified by quantitative RT-PCR and western blot analysis. Roscovitine exhibited a clear dose-dependent anti‑proliferative and pro‑apoptotic effect in the A172cell line, while G28cells showed a anti-proliferative effect only at 100µM. The results of the flow cytometric (FACS) analysis revealed a dose-dependent increase of the G2/M and sub-G1fractions in A172cells, while G28cells responded with an elevated sub-G1fraction only at the highest concentration. Roscovitine led to a dose‑dependent decrease of transcripts of p53, CDK7 and cyclinsA and E and an increase of >4-fold of p21 in A172cells. In G28cells, a dose‑dependent induction of CDK2, p21 and cyclinD was observed between 10 and 50µM roscovitine after 72h, however, at the highest concentration of 100µM, all investigated genes were downregulated. Roscovitine exerted clear dose-dependent anti-proliferative and pro-apoptotic effects in A172cells and less distinct effects on G28cells. In A172cells, roscovitine led to G2/Marrest and induced apoptosis, an effect accompanied by induced p21 and a reduced expression of CDK2, 7 and 9 and cyclinsA andE. These effects requre further studies on a larger scale to confirm whether roscovitine can be used as a therapeutic agent against glioblastoma.