Figure 6

Inhibition of ER stress response protects against CBD-induced cell death. (a) JS1 cells were transfected with siRNA against ATF4. After 16 h, cells were incubated with 5 μM CBD in serum-free media for 8 h. Western blot analysis was used to determine PARP, ATF4, and CHOP expression, presented as fold over control±S.E.M. for n=four independent experiments. (b) LX-2 cells were treated with 5 μM CBD in serum-free media for 8 h in the presence or absence of 10 μM imatinib to inhibit ER stress. Expression of PARP, CHOP, and phospho-JNK was determined by western blot analysis and is presented as fold over vehicle±S.E.M. for n=four independent experiments. (c) Acid phosphatase activity was used to measure LX-2 cell viability following treatment with CBD and imatinib as in (b). Cell viability is expressed as mean percent of control acid phosphatase activity±S.E.M. of triplicate experiments. ^***P<0.001; ^**P<0.05