Figure 8.

YM155 induces autophagic cell death in breast cancer cells. (A) MDA-MB-231 cells were cultured in RPMI containing either 10 or 1% FBS for 48 h. Expression of LC3B was examined by Western blotting. Equal protein loading was verified by actin. (B) MDA-MB-231 cells were cultured in RPMI containing 1% FBS and treated with either 3MA or CQ for 72 h. Cell viability was determined by the MTT assay. A statistically significant difference in the viability of cells treated with 1% FBS versus 1%FBS + 3MA/CQ is denoted by an asterisk; *P < 0.05. (C) Breast cancer cells were treated with the indicated concentrations of YM155 with or without 3MA or Z-DEVD-FMK for 72 h. Cell viability was determined by the MTT assay. (D) Breast cancer cells were treated with either DMSO (control) or 2×IC₅₀ YM155 with or without CQ for 72 h. Cell viability was assessed by MTT assay. A statistically significant difference in the viability of cells treated with YM155 versus YM155 + CQ is denoted, *P < 0.05. (E) MDA-MB-231 cells were treated with DMSO (control), rapamycin or YM155 with or without rapamycin for 72 h. Cell viability was assessed by MTT assay. A statistically significant difference in the viability of cells treated with YM155 + rapamycin versus YM155 or rapamycin alone is denoted, *P < 0.05. (F) MDA-MB-231 cells were treated with either DMSO (-ve control) or 2×IC₅₀ YM155 with or without CQ or BAF. Cytotoxicity was determined by LDH-cytotoxicity assay.