Figure 2

Cytotoxic activity of chemotherapy or erlotinib and EGFR pathway activation in LCSCs. (a) LCSCs were exposed to the indicated drugs and cell viability evaluated after 48 h and indicated as percentage versus control cells. (b) Time course of erlotinib-induced cytotoxicity. Cell viability was evaluated by CellTiter-Glo after 48 and 72 h of erlotinib exposure. (c) Immunoblot analysis of the indicated components of the EGFR pathways. (d) Long-term effects of erlotinib on LCSCs. Percentage of clonogenic cells in soft agar assay of erlotinib-treated versus control is indicated for each LCSC analyzed. (e) Cytotoxic activity of erlotinib in LCSCs (-S) and corresponding differentiated cells (-D) of each sample as indicated. Cells were exposed to erlotinib for 3 days and cell viability evaluated by CellTiter-Glo. (f) Immunoblot comparison of EGFR expression and activation in LCSCs (-S) and their in vitro differentiated counterparts (-D). Mean±S.D. of three independent experiments is always shown. *P<0.05; **P<0.01; ***P<0.001