• Senescent bone marrow mesenchymal stem cells (BMSCs) upregulate galectin-3 expression, which is associated with the senescence phenotype.
• Conditioned medium from senescent BMSCs promotes proliferation and inhibits apoptosis of multiple myeloma U266 cells, with increased BCL-2 expression.
• Galectin-3 levels are significantly elevated in the bone marrow of multiple myeloma patients compared to healthy controls.
• The findings suggest that senescent BMSCs contribute to multiple myeloma progression via paracrine galectin-3, offering potential therapeutic targets.