ATF6 and Familial prostate cancer: Finally, treatment with 250 nmol/L NXP800, but not its inactive chemical control CCT365248 at this concentration, resulted in increased eIF2α phosphorylation and ATF4, ATF6, and IRE1 protein expression in VCaP, LNCaP95, and 22Rv1 prostate cancer cells (Fig. 3G).