Solasodine targets NF-κB signaling to overcome P-glycoprotein mediated multidrug resistance in cancer.

ABSTRACT

P-glycoprotein (P-gp) mediated multidrug resistance (MDR) is the leading cause of chemotherapy failure since it causes the efflux of chemotherapeutic drugs from the cancer cells. Solasodine, a steroidal alkaloid and oxaspiro compound, present in the Solanaceae family showed significant cytotoxic effects on various cancer cells. However, the effect of solasodine on reversing P-gp mediated drug resistance is still unknown. Primarily in this study, the integrative network pharmacology analysis found 71 common targets between solasodine and cancer MDR, among them NF-κB was found as a potential target. The results of immunofluorescence analysis showed that solasodine significantly inhibits NF-κB-p65 nuclear translocation which caused downregulated P-gp expression in KBChR-8-5 cells. Further, solasodine binds to the active sites of the TMD region of P-gp and inhibits P-gp transport activity. Moreover, solasodine significantly promotes doxorubicin intracellular accumulation in the drug resistant cells. Solasodine reduced the fold resistance and synergistically sensitized doxorubicin's therapeutic effects in KBChR-8-5 cells. Additionally, the solasodine and doxorubicin combination treatment increased the apoptotic cell populations and G2/M phase cell cycle arrest in KBChR-8-5 cells. The MDR tumor bearing xenograft mice showed tumor-suppressing characteristics and P-gp downregulation during the combination treatment of solasodine and doxorubicin. These results indicate that solasodine targets NF-κB signaling to downregulate P-gp overexpression, inhibit P-gp transport activity, and enhance chemosensitization in MDR cancer cells. Considering its multifaceted impact, solasodine represents a potent natural fourth-generation P-gp modulator for reversing MDR in cancer.