Mechanism regulation of endoplasmic reticulum stress in multiple myeloma cells: modulation of the UPR, UPS, autophagy, HSPs, and potential therapeutic targets

Introduction Multiple myeloma (MM) progression results from complex interactions between tumor cells, cytokines, and the tumor microenvironment (TME). MM cells constantly produce paraprotein, causing endoplasmic reticulum stress (ERS). Cell survival relies on adaptive mechanisms such as the unfolded protein response (UPR), autophagy, and heat shock proteins (HSPs). This review emphasizes the role of ERS in MM cell survival and explores emerging therapeutic strategies targeting ERS-related pathways, including chemical agents, natural compounds, and inhibitors of autophagy, HSPs, or the proteasome.