Fig. 2.

Oncogenic Kras expression stimulated autophagy in nontransformed human ductal HPDE cells. A: immunoblots demonstrated a Kras-mediated increase in phosphorylated ERK (p-ERK) in HPDE/Kras vs. HPDE cells. *p-ERK1 and *p-ERK2 are p-ERK bands visualized with correspondingly longer and shorter exposure. The data are representative of 2 independent experiments that gave the same results. The densitometric intensity of the p-ERK band was normalized to that of total ERK in the same sample and further normalized to that in HPDE cells, as shown below the blot. B–J: HPDE and HPDE/Kras cell lines were cultured either in normal conditions (B and C) or subjected to stresses, as specified in Fig. 1, and cultured in the presence and absence of E64D + Pepstatin A (E/P) for 24 h (B, C, and H–J) or for indicated times (D–G). C and H–J: densitometric intensities of LC3-II bands were normalized to that of GAPDH in the same sample. The bands were normalized further to that in HPDE cells with no inhibitors (C), to control HPDE (H and I), or to control HPDE/Kras cells (J). Values are means ± SE (at least 3 independent experiments). *P < 0.05 vs. HPDE cells cultured without inhibitors; #P < 0.05 vs. HPDE/Kras cells cultured without inhibitors; ^P < 0.05 vs. HPDE cells cultured in the same conditions; $P < 0.05 vs. control of the same cell line (H–J).