Effect of dasatinib on expression of Src and downstream signaling in parental and resistant cells and identification of Src dimers.

<p>(A) Western blot showing expression of total and phosphorylated Src (Tyr⁴¹⁶) in lysates from parental (T47D/S2 and T47D/S5), tamoxifen (TR-1 and TR-2) and fulvestrant (182^R-1 and 182^R-2) resistant cell lines grown under their standard conditions. β-actin was used as loading control. (B) Western blot showing expression of total and phosphorylated Akt (Ser⁴⁷³), Erk (Thr²⁰²/Tyr²⁰⁴) and Src (Tyr⁴¹⁶) in lysates from parental (T47D/S2 and T47D/S5), tamoxifen (TR-1 and TR-2) and fulvestrant (182^R-1 and 182^R-2) resistant cell lines grown with or without dasatinib (1 μM) for 1 hour. Hsp70 was used as loading control. (C) Src dimers in parental (T47D/S2 and T47D/S5), tamoxifen (TR-1 and TR-2) and fulvestrant (182R-1 and 182R-2) resistant cell lines grown under their standard conditions. Src protein was immunoprecipitated from 1 mg total protein lysates. Western analysis for HER receptors, Src and ER was performed on both total protein lysates and immunoprecipitated samples. A representative experiment out of two is shown. β-actin was used as loading control.