Effects of PKC412 and imatinib on expression of Hsp32 in neoplastic cells. (A) Ton.Kit.D816V-27 cells were starved from IL-3 and kept in control medium or were induced to express KIT D816V by exposure to doxycycline (1 μg/mL) in the presence or absence of PKC412 (1 μM) or STI571 (1 μM) at 37°C for 16 hours. Then, cells were harvested and subjected to Western blotting using antibodies against Hsp32 or β-actin (loading control). (B) Ton.Kit.wt cells were starved (control) or were induced to express wt KIT by exposure to doxycycline. To activate wt KIT, cells were exposed to SCF (100 ng/mL). Then, cells were kept in control medium, PKC412 (1 μM), or STI571 (1 μM) at 37°C for 18 hours, and then subjected to Western blotting using antibodies against murine Hsp32 or β-actin. (C-D) HMC-1.2 cells (C) and HMC-1.1 cells (D) were incubated in control medium, PKC412 (1 μM), or STI571 (1 μM) at 37°C for 24 hours. After exposure to drugs, cells were harvested, and Western blots were performed using antibodies against Hsp32 or β-actin.