1. Bcl-xL expression in tumors antagonizes the therapeutic efficiency of ERBB2 downregulation.
Bcl-xL expression in tumors antagonizes the therapeutic efficiency of ERBB2 downregulation. Subcutaneous tumors were induced in nude mice by injection of NIH3T3 cells expressing ERBB2, ERBB2 and Bcl-xL, as well as cells expressing ERBB2 mock-transfected with an empty vector. Downregulation of ERBB2 was achieved by daily injections of anhydrotetracycline for 7 d. The alteration of tumor volume compared with the day of the first anhydrotetracycline injection (day 0) is given. A, NIH3T3 cells expressing ERBB2 and Bcl-xL (Bcl-xL) versus NIH3T3 cells expressing ERBB2 and mock-transfected with an empty vector (MOCK). B, NIH3T3 cells expressing ERBB2 and Bcl-xL (Bcl-xL) versus NIH3T3 cells expressing ERBB2 (ERBB2). C, NIH3T3 cells expressing ERBB2 and mock-transfected with an empty vector (MOCK) versus NIH3T3 cells expressing ERBB2 (ERBB2). Comparing mock-transfected cells to the parental NIH3T3-ERBB2 cells showed that the retroviral transduction itself might have induced a slight increase in resistance (C). However, this small difference cannot explain the much larger effect observed in the presence of Bcl-xL (A and B).
Ilka Brigitte Petry et al. Clin Cancer Res 2010;16:
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