Lack of IL-6 rescue on TRAIL-induced MM cell death.

MTT colorimetric assay (A) and PI staining (B), performed in MM-1S cells cultured with TRAIL (1000 ng/mL) in the presence or absence of IL-6 (100 ng/mL), document that IL-6 does not abrogate TRAIL-induced cell death. In panel B, the shaded cell cycle profile corresponds to MM-1S cells cultured with IL-6. The unshaded profile, corresponding to cells treated with TRAIL in the presence of IL-6, is identical to the one of MM-1S cells treated with TRAIL alone (data not shown).