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

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.

Andrographolide reverts multidrug resistance in KBChR 8-5 cells through AKT signaling pathway.

Multidrug resistance (MDR) is a major obstacle in cancer chemotherapy. P-glycoprotein (P-gp) one of the ATP-binding cassette (ABC) transporters plays an important role in MDR. In this study, we examined the sensitizing property of andrographolide (Andro) to reverse MDR in the drug-resistant KBChR 8-5 cells. Andro exhibited increased cytotoxicity in a concentration-dependent manner in the P-gp overexpressing KBChR 8-5 cells. Furthermore, Andro showed synergistic interactions with PTX and DOX in this drug-resistant cells. Andro co-administration enhanced PTX- and DOX-induced cytotoxicity and reduced cell proliferation in the MDR cancer cells. Moreover, reactive oxygen species (ROS) were elevated with a decrease in the mitochondrial membrane potential (MMP) during Andro and chemotherapeutic drugs combination treatment in the drug-resistant cells. Furthermore, Andro and PTX-induced cell cycle arrest was observed in the drug-resistant cell. We also noticed that the expression of ABCB1 and AKT were downregulated during Andro (4 µM) treatment. Furthermore, Andro treatment enhanced the expression of caspase 3 and caspase 9 in the combinational groups that support the enhanced apoptotic cell death in drug-resistant cancer cells. Therefore, the results reveal that Andro plays a role in the reversal of P-gp-mediated MDR in KBChR 8-5 cells which might be due to regulating ABCB1/AKT signaling pathway.

Auranofin sensitizes breast cancer cells to paclitaxel chemotherapy by disturbing the cellular redox system.

The intrinsic redox status of cancer cells limits the efficacy of chemotherapeutic drugs. Auranofin, a Food and Drug Administration-approved gold-containing compound, documented with effective pharmacokinetics and safety profiles in humans, has recently been repurposed for anticancer activity. This study examined the paclitaxel-sensitizing effect of auranofin by targeting redox balance in the MDA-MB-231 and MCF-7 breast cancer cell lines. Auranofin treatment depletes the activities of superoxide dismutase, catalase, and glutathione peroxidase and alters the redox ratio in the breast cancer cell lines. Furthermore, it has been noticed that auranofin augmented paclitaxel-mediated cytotoxicity in a concentration-dependent manner in both MDA-MB-231 and MCF-7 cell lines. Moreover, auranofin increased the levels of intracellular reactive oxygen species (observed using 2, 7-diacetyl dichlorofluorescein diacetate staining) and subsequently altered the mitochondrial membrane potential (rhodamine-123 staining) in a concentration-dependent manner. Further, the expression of apoptotic marker p21 was found to be higher in auranofin plus paclitaxel-treated breast cancer cells compared to paclitaxel-alone treatment. Thus, the present results illustrate the chemosensitizing property of auranofin in MDA-MB-231 and MCF-7 breast cancer cell lines via oxidative metabolism. Therefore, auranofin could be considered a chemosensitizing agent during cancer chemotherapy.

Natural medicinal compounds target signal transduction pathways to overcome ABC drug efflux transporter-mediated multidrug resistance in cancer.

ATP-binding cassette (ABC) transporters such as ABCB1, ABCG2, and ABCC1 are the major players in drug efflux-mediated multidrug resistance (MDR), which severely affects the efficacy of chemotherapy. Several synthetic compounds block the drug transport by ABC transporters; however, they exhibit a narrow therapeutic window, and produce side effects in non-target normal tissues. Conversely, the downregulation of the expression of ABC drug transporters seems to be a promising strategy to reverse MDR in cancer cells. Several signaling pathways, such as NF-κB, STAT3, Gli, NICD, YAP/TAZ, and Nrf2 upregulate the expression of ABC drug transporters in drug-resistant cancers. Recently, natural medicinal compounds have gained importance to overcome the ABC drug-efflux pump-mediated MDR in cancer. These compounds target transcription factors and the associated signal transduction pathways, thereby downregulating the expression of ABC transporters in drug-resistant cancer cells. Several potent natural compounds have been identified as lead candidates to synergistically enhance chemotherapeutic efficacy, and a few of them are already in clinical trials. Therefore, modulation of signal transduction pathways using natural medicinal compounds for the reversal of ABC drug transporter-mediated MDR in cancer is a novel approach for improving the efficiency of the existing chemotherapeutics. In this review, we discuss the modulatory role of natural medicinal compounds on cellular signaling pathways that regulate the expression of ABC transporters in drug-resistant cancer cells.

Reversal of P-glycoprotein-mediated multidrug resistance by natural N-alkylated indole alkaloid derivatives in KB-ChR-8-5 drug-resistant cancer cells.

Multidrug resistance (MDR) remains a significant challenge in cancer chemotherapy due to the overexpression of ATP-binding cassette drug-efflux transporters, namely P-glycoprotein (P-gp)/ATP-binding cassette subfamily B member 1. In this study, derivatives of N-alkylated monoterpene indole alkaloids such as N-(para-bromobenzyl) (NBBT), N-(para-methylbenzyl) (NMBT), and N-(para-methoxyphenethyl) (NMPT) moieties were investigated for the reversal of P-gp-mediated MDR in drug-resistant KB colchicine-resistant 8-5 (KB-ChR-8-5) cells. Among the three indole alkaloid derivatives, the NBBT exhibited the highest P-gp inhibitory activity in a dose-dependent manner. Further, it significantly decreased P-gp overexpression by inactivating the nuclear translocation of the nuclear factor kappa B p-50 subunit. In the cell survival assay, doxorubicin showed 6.3-fold resistance (FR) in KB-ChR-8-5 cells compared with its parental KB-3-1 cells. However, NBBT significantly reduced doxorubicin FR to 1.7, 1.3, and 0.4 and showed strong synergism with doxorubicin for all the concentrations studied in the drug-resistant cells. Furthermore, NBBT and doxorubicin combination decreased the cellular migration and showed increased apoptotic incidence by downregulating Bcl-2, then activating BAX, caspase 3, and p53. The present findings suggest that NBBT could be a lead candidate for the reversal of P-gp- mediated multidrug resistance in cancer cells.