Efek Salinomycin Dibandingkan Doxorubicin serta Kombinasinya sebagai Inhibitor Multidrug Resistance dan Sebagai Regulator Apoptosis pada Kultur Sel Osteosarkoma (U2OS) Invitro: Evaluasi Terhadap Ekspresi Gen Bcl2, Gen Bax, Gen P-glycoprotein, NF-κB, dan IκBα

Abstract

Background: Osteosarcoma is a primary bone malignancy often resistant to chemotherapy, primarily due to overexpression of P-glycoprotein (Pgp). This study aims to evaluate the effects of salinomycin, compared to doxorubicin and their combination, on apoptosis regulation and multidrug resistance gene expression in U2OS osteosarcoma cells in vitro. Methods: A true in vitro experimental study was conducted using six groups: control, doxorubicin, three salinomycin doses, and a combination group. Cell viability (MTT assay) and gene expression of Bax, Bcl2, Pgp, NF-κB, and IκBα were assessed via qRT-PCR. Results: MTT assay revealed that the IC50 value of salinomycin was 0.0125 μM, while that of doxorubicin was 0.1 μg/mL. Salinomycin significantly reduced cell viability, particularly at a dose of 0.025 μM. The combination of salinomycin and doxorubicin resulted in the highest expression of the pro-apoptotic gene Bax (4.16- fold), whereas the lowest expression of the anti-apoptotic gene Bcl2 was observed at 0.005 μM salinomycin (0.61-fold). The combination therapy also showed a reduction in P-glycoprotein expression (0.47-fold), indicating an effect on multidrug resistance. In addition, the lowest NF-κB expression was found at 0.005 μM salinomycin, while the highest IκBα expression was observed at 0.025 μM salinomycin. These findings suggest that salinomycin acts by suppressing the NF- κB pathway and enhancing apoptosis. Conclusion: Salinomycin exhibits potential as a multidrug resistance inhibitor by modulating the NF-κB pathway and suppressing Pgp expression. When combined with doxorubicin, it enhances apoptotic signaling, suggesting its role as a promising adjuvant therapy for chemoresistant osteosarcoma.