Hexamethylene bisacetamide (HMBA)-induced cell death in P-glycoprotein (P-gp) cell lines.

P-gp⁺ (A7) and P-gp^- (CCRF) CEM cells (A), P-gp⁺ (LoVo-adr) and P-gp^- (LoVo) LoVo colon carcinoma cells (B), and P-gp⁺ (KVIN) and P-gp^-(K562) K562 myeloid cells (C) were cultured for 72 hours with 0-20 mmol/L HMBA or 100-200 ng/mL doxorubicin. Cells were counted at 72 hours by trypan blue exclusion as described in “Materials and methods.” (D) After 3 days in culture with 0-20 mmol/L HMBA or 100 ng/mL doxorubicin, A7 and CCRF cells were plated out in soft agar. Colonies were scored after 2 weeks in culture as described in Materials and methods section.