Shenmai injection enhances cisplatin-induced apoptosis through regulation of Mfn2-dependent mitochondrial dynamics in lung adenocarcinoma A549/DDP cells.

Chemoresistance is the biggest obstacle in cancer treatment. Our previous study demonstrated that Shenmai injection (SMI), a Chinese herbal medicine, enhanced the antitumor effect of cisplatin via glucose metabolism reprogramming. This study aimed to further determine whether the SMI sensitizes the non-small cell lung cancer (NSCLC) cells to cisplatin through regulation mitochondrial dynamics. The Kaplan-Meier Plotter database was used to investigate the relationship between mRNA expression of mitofusin-2 (Mfn2) and the survival analysis of NSCLC patients. The protein expression of Mfn2 in a lung adenocarcinoma tissue chip was detected by immunohistochemistry staining. The expression of Mfn2 and ATAD3A were compared between cisplatin-sensitive A549 and cisplatin-resistant A549/DDP cells. Additionally, A549/DDP cells were co-treated with cisplatin and SMI to detect mitochondrial morphology by fluorescent staining, apoptosis-related protein expression with Western blotting, and mitochondrial membrane potential (ΔΨm) with flow cytometry analysis. The mean survival time of the Mfn2 group was significantly lower than that of the Mfn2 group by Kaplan-Meier Plotter database analysis, and the Mfn2 protein expression level was lower in cancer tissues than in adjacent tissues. The combination of SMI and cisplatin induced dynamic changes in A549/DDP cells, with increased mitochondrial fusion followed by upregulation of Mfn2 and downregulation of ATAD3A and reduced mitochondrial mass and ΔΨm. Moreover, SMI significantly enhanced cisplatin-induced A549/DDP apoptosis, upregulated Bax and the active subunit of caspase-3, and downregulated Bcl-2 expression, as shown via Hoechst staining and flow cytometry analysis. Our findings suggest SMI enhances cisplatin-induced apoptosis through regulation of Mfn2-dependent mitochondrial dynamics in cisplatin-resistant lung adenocarcinoma cells.