FAs secreted from adipocytes are directly taken up by myeloma cells. (A) Representative images stained by using BODIPY fluorophore-labeled 12-carbon long-chain FA and 16-carbon long-chain FA in murine 5TGM1 and human-derived OPM2 myeloma cells. (B) Flow cytometric analysis of BODIPY C₁₂ FA uptake by 5TGM1 and OPM2 MM cells preincubated with the fluorescent dodecanoic acid FA measured at 1, 10, 30, and 60 minutes. (C) Measurement of FA uptake at 1, 10, 30, 60, and 120 minutes in MM cells using the MAK156 kit (MilliporeSigma). The kit uses a fluorescent dodecanoic FA substrate whose uptake into cells results in an increase in fluorescent intensity measured at λ_ex = 485/λ_em = 515 nM. (D) Fluorescent intensity profiles of LipidTOX Deep Red–labeled lipids transferred from adipocytes to MM cells (5TGM1 and OPM2) either cultured alone or cocultured with OP9 adipocytes. (E) Reduction of labeled BODIPY C₁₂ uptake by 5TGM1 and OPM2 MM cells through inhibition of adipocyte lipolysis by acipimox treatment. Data are presented as mean ± standard error of the mean. *P < .05.