Metabolic reprogramming induced by PSMA4 overexpression facilitates bortezomib resistance in multiple myeloma.

Multiple myeloma(MM) remains incurable with high relapse and chemoresistance rates. Differentially expressed genes(DEGs) between newly diagnosed myeloma and secondary plasma cell leukemia(sPCL) were subjected to a weighted gene co-expression network analysis(WGCNA). Drug resistant myeloma cell lines were established. Seahorse XF analyzer was applied to detect the metabolism reprogramming associated with the hub gene. The metabolic relevance and the underlying mechanism of the hub gene in myeloma resistance were explored via in vitro experiments. A total of 1310 DEGs were used to construct five co-expression modules. Gene function enrichment analysis demonstrated that candidate hub genes were closely related to oxidative phosphorylation. We performed prognostic analysis and identified PSMA4 as the key hub gene related to the extramedullary invasion of myeloma. The in vitro experiments demonstrated bortezomib resistant myeloma cell lines exhibited high PSMA4 expression, improved oxidative phosphorylation activity with increased ROS level. PSMA4 knockdown re-sensitize resistant myeloma cells via suppressing oxidative phosphorylation activity. Further investigation revealed that PSMA4 induced a hypoxia state which activated the HIF-1α signaling pathway. PSMA4 induces metabolic reprogramming by improving oxidative phosphorylation activity which accounts for the hypoxia state in myeloma cell. The activated HIF-1α signaling pathway causes bortezomib resistance via promoting anti-apoptotic activity in myeloma.