Benzimidazoisoquinoline derivatives inhibit glioblastoma cell proliferation through down-regulating Raf/MEK/ERK and PI3K/AKT pathways.

Background: Recent studies showed that benzimidazoleisoquinolinone derivatives exhibit anticancer activity against human cancer cell lines. The aim of this study is to evaluate the anti-tumor effects and mechanisms of benzimidazoleisoquinolinones in isocitrate dehydrogenase-wildtype subtype of human glioblastoma (GBM) cells.

Methods: Human U87 and LN229 cell lines were used to perform the experiments. MTT was applied to screen the effective small molecular inhibitors suppressing growth of GBM cells. Colony formation and BrdU staining assays were performed to assess the inhibition effect of compound- on the proliferation of GBM cells. The cell cycle and apoptosis were measured by flow cytometry and western blot to analyze the changes of the relative protein expressions and their signal pathways.

Results: Compound- could suppress GBM cells in a time- and dose-dependent manner. Treatment of compound- could arrest cell cycle in S phase through up-regulating P21 and P53, and down-regulating cyclin A and E in a dose-dependent manner. Compound- also induced mitochondrial-dependent apoptosis by increasing Bax, cleaved caspase-3, cleaved caspase-9 and poly ADP-ribose polymerase expression, and decreasing Bcl-2 expression. Moreover, phosphorylated (p)-AKT and p-ERK levels relating to cell proliferation were dramatically decreased in U87 and LN229 cells.

Conclusions: Our results suggest that it is the first time to report the compound- with benzimidazoleisoquinolinone core playing antitumor activity in human glioblastoma cells by inhibiting Raf/MEK/ERK and PI3K/AKT signaling pathways, and it could be as a lead compound for the further development of targeted glioblastoma cancer therapy.