Figure 7.

PTEN is required for NHERF1-induced increase in sensitivity to STI-571. (a) Phosphatase and tensin homolog (PTEN)-negative MDA-MB-468 cells were infected with Na⁺/H⁺ exchanger regulatory factor 1 (NHERF1) small interfering RNA (siRNA; 910) or control (Babe) retrovirus. Their NHERF1 expression was measured by immunoblotting. Theses cells were treated with STI-571 (3 and 10 μmol/l) for 2 days. The cell survival was measured using MTT assay. (b) MCF10A cells with varying NHERF1 and PTEN levels through retroviral over-expression (NHERF1) or siRNA knockdown (PTEN-KD) were treated with 3 μmol/l STI-571 for 2 days before MTT assay. The reading of untreated control cells was arbitrarily set at 100%. Data from three to five independent experiments are presented (**P < 0.01).