Suppression of the Antioxidant System and PI3K/Akt/mTOR Signaling Pathway in Cisplatin-Resistant Cancer Cells by Quercetin

We studied the effect of quercetin on ovarian adenocarcinoma SKOV-3 cell line and isogenic subline SKOV-3/CDDP resistant to the anticancer drug cisplatin. It was found that in resistant cells, quercetin in a concentration of 100 μM that causes a decrease in the cell viability suppressed the expression of genes encoding the key antioxidant enzymes (SOD2, CAT, GPX1, and HO-1), transcription factor Nrf2, and kinases of the PI3K/Akt/mTOR signaling pathway. In parental cells, quercetin, on the contrary, increased the expression of these genes. The results confirm the redox-dependent regulation induced by quercetin and its opposite nature in cisplatin-sensitive and cisplatin-resistant cancer cells.