Bcl-X_L antisense inhibits heme synthesis without altering α- and β-globin mRNA expression in DMSO-induced MEL cells.

(A) Expression of α- and β-globin transcripts in 745A/Neo and 745A/Bcl-X_LAS cells. Cells were seeded at 10⁵cells/mL with or without 2% DMSO. After 4 days of culture, total RNA was isolated and subjected to RT-PCR as described in “Materials and methods.” α-globin, β-globin, and GAPDH were amplified for 20, 25, and 30 cycles. Aliquots of the PCR reactions were separated on 1.2% agarose gels and visualized with ethidium bromide. (B) Semiquantitative RT-PCR analysis of α- and β-globin in 745A/Neo (■) and 745A/Bcl-X_LAS (▪) cells cultured for 4 days in the absence or in the presence of DMSO. Values are taken from densitometric analysis of bands obtained with 25 cycle amplifications and are normalized to GAPDH values from the same sample. (C) Heme production in 745A/Neo and 745A/Bcl-X_LAS cells. Cells were seeded at 10⁵ cells/mL with or without 2% DMSO and harvested at the times indicated (days) after growth initiation. Heme concentration was determined by a fluorometric procedure.