Adiponectin induces myeloma cell apoptosis. (A) Adiponectin receptor expression measured by RT-PCR in 5TGM1 myeloma cells, ST2, C57Bl6, and KaLwRij BMSCs. (B) Western blot of AMPK activation after treatment of 5TGM1 myeloma cells with 5 to 15 μg/mL adiponectin for 48 hours. (C) Western blot of p38 kinase activation after treatment of 5TGM1 myeloma cells with 5 to 10 μg/mL adiponectin for 48 hours. (D) Proportion of apoptotic 5TGM1 myeloma cells, as measured by annexin V/propidium iodide staining and flow cytometric analysis, after treatment with 5 μg/mL adiponectin for 48 hours. **P < .01, compared with control (data represent 3 independent experiments). (E) Western blot of cleavage of caspase 3 after treatment of 5TGM1 myeloma cells with 5 to 15 μg/mL adiponectin for 48 hours. (F) Western blot of cleavage of PARP-1 after treatment of 5TGM1 myeloma cells with 5 to 15 μg/mL adiponectin for 48 hours.