Figure 3. HIF-1α is required for hypoxic-mediated lapatinib resistance and signaling in ERBB2-expressing cells.

(A) Cell lysates from cells stably expressing control or HIF-1α shRNA were collected for immunoblot analysis. (B) Cells were treated with increasing doses of lapatinib under hypoxic conditions and then stained with crystal violet. (C) Cell viability was assessed with cells as described in B. (D) Cells expressing control or HIF-1α shRNA were treated with vehicle control or lapatinib under hypoxic conditions. Cell lysates were then collected for immunoblot analysis. Error bars indicate S.E. (*p ≤ 0.05).