Figure 1.

Adenoviral overexpression of BCL-XL confers short-term protection to LSK cells. (A) Adenoviral vectors for human BCL-XL expression were used. (B) WT LSK cells were transduced with Ad5-Venus viruses and cultured in the presence of cytokines (SCF, TPO, and Flt3L). Venus expression was determined by flow cytometry at the indicated time points. Bars represent means ± SEM (n = 3 independent experiments). (C) HeLa cells were transduced with the indicated adenoviruses, and BCL-XL protein was determined 48 h later. (D) LSK cells were either left untreated or transduced with the indicated adenoviruses and, at the same time, treated with 1 µg/ml etoposide. After 24 h, apoptosis was determined by flow cytometry. Bars represent means of three to four independent experiments ± SEM (Mann–Whitney test; P = 0.05 untreated vs. Ad5–BCL-XL and Ad5-Venus vs. Ad5–BCL-XL). (E) Adenovirally transduced cells were subjected to cytokine withdrawal, and apoptosis was determined by flow cytometry at the indicated time points. Bars represent means of four independent experiments ± SEM (Mann–Whitney test; P = 0.02 for untreated vs. Ad5–BCL-XL and Ad5-Venus vs. Ad5–BCL-XL at day 4 and 6; P = 0.04 for Ad5-Venus vs. Ad5–BCL-XL at day 8). (F) 300 LSK cells were transduced with adenoviruses or left untreated and cultured in MethoCult medium supplemented with rmSCF, rmIL-3, rhIL-6, and rhEpo. After 7 d, colonies were counted, and the colony type was determined based on morphological features. Bars represent means of n = 4 independent experiments ± SEM (Mann–Whitney test; P = 0.04 for M colonies).