CHK2 is required for prostate cancer cell growth in response to hormone. CyQuant Assay measured cell number 7 days after transduction. (A) CHK2 overexpression decreases cell growth. Cell lysate was blotted for HA (exogenous CHK2), CHK2 (endogenous CHK2), and ERK1/2. The effect of empty vector (pLMJ1) or wild-type CHK2 (pLJM1-wtCHK2) overexpression on growth in Rv1 and VCaP cells in the absence or presence of 0.05nM R1881, n=3. (B) Overexpression of CHK2 in cells depleted of CHK2 abrogated the growth effect of CHK2 knockdown alone. Cell lysate was blotted for HA, CHK2, and ERK1/2. The effect of empty vector (pLKO), CHK2 shRNA, or CHK2 shRNA/wtCHK2 overexpression on growth in LNCaP, Rv1, and C42 cells in the absence or presence of 0.05nM R1881, n=3. Statistical analysis was performed using two-way ANOVA. * p<0.01.