Platinum-based chemotherapy still represents the standard first-line approach for NSCLC patients, although primary or secondary resistance is frequently observed. Recently the Shh pathway has been associated with resistance to platinum-based chemotherapy in NSCLC. The aim of this work is to investigate whether a combined treatment with cisplatin and the Hedgehog-pathway inhibitor vismodegib could potentiate the anti-tumour effect and to explore possible mechanisms of this synergy.
Two Human NCSLC cell lines A549 and H460 were treated with single agent Cisplatin, single agent Vismodegib and a combination of the two drugs. MTT cytotoxicity assays were performed and the data were analysed with CompuSyn software. Experiments of apoptosis and cell cycle were done by using flow cytometer. Immunofluorescence with lysoTracker as well as western blot (WB) analysis for the LC3B protein were performed to analyse autophagy.
The CompuSyn analysis showed an important synergistic effect of cisplatin + Vismodegib. Combined treatment induced a significant increase in cellular apoptosis compared with single agent cisplatin. The cell cycle analyses revealed a block in S-phase with the combination treatment. The lysoTracker immunofluorescence assay showed that cisplatin induces an increase of autophagy, while the combination with vismodegib strongly reduces it, finally reverting this effect. These findings were confirmed by WB analysis for LC3B which is significantly increased by single agent cisplatin and reduced by the combined treatment.
Combined treatment with cisplatin and vismodegib has a synergistic effect with an increase in cancer cell apoptosis. Autophagy has been described as a mechanism through which cancer cells escape cisplatin-induced cytotoxicity. Combining cisplatin with vismodegib leads to an inhibition of autophagy, so that it could suggest a new therapeutic approach.
Clinical trial identification
Legal entity responsible for the study
Università della Campania “Luigi Vanvitelli”
All authors have declared no conflicts of interest.