Novel Derivatives of Tetrahydrobenzo (g) Imidazo[α-1,2] Quinoline Induce Apoptosis Via ROS Production in the Glioblastoma Multiforme Cells, U-87MG.

BACKGROUND

Despite newer therapeutic approaches against glioblastoma multiforme (GBM), the severely poor prognosis and treatment resistance are still disadvantages that slow down the patient's recovery process. Consistent with the need to develop more effective and optimized therapies to control GBM cell growth, the effects of a new series of tetrahydrobenzo(g)imidazo[α-1,2]quinolone derivatives on GBM cell growth and the underlying mechanism is investigated in the current study.

METHODS

U-87MG cell line, glioblastoma multiforme and normal skin fibroblast cell line, AGO1522 were used to study the anticancer effects of 5 derivatives of tetrahydrobenzo(g)imidazo[α-1,2]quinolone and paclitaxel as a standard drug. The cytotoxic effect on cell growth was assessed using the MTT assay. Annexin V FITC staining and PI staining were applied to detect apoptosis and cell cycle distribution using flow cytometry. The extent of reactive oxygen species (ROS) formation was assessed using the fluorescent probe 7-dichlorofluorescin diacetate and caspase-3 activity using the colorimetric assay kit.

RESULTS

Among the 5 derivatives of tetrahydrobenzo(g)imidazo[α-1,2]quinolone, the 5c derivative (5-(6-bromo-2-chloroquinolin-3-yl)-9a-hydroxy-8,8-dimethyl-4-Nitro-2,3,5,5a,7,8,9,9a-octahydroimidazo[α-1,2]quinoline-6(1H)) showed the strongest cytotoxic effect on U-87MG cells in a time and Dose-dependent manner compared to the other derivatives and paclitaxel. The IC50 (11.91 M) of the 5c derivative induced apoptosis accompanied by a significant increase in sub-G1 and super-G2 phases of U-87MG cells. The increased level of cellular ROS and caspase 3 activity after treatment of U-87MG cells with 5c derivative was significant compared to untreated cells.

CONCLUSION

Our data provide insights into the potent anticancer effects of the 5c-derivative of tetrahydrobenzo(g)imidazo[α-1,2]quinolone on GBM cells via the caspase-dependent apoptotic pathway, which may merit further attention.