Inhibition than CIT shRNA-1, which parallels the effect on kinase mRNA knockdown, where CIT shRNA-2 reduced CIT mRNA levels more than CIT shRNA-1. However, the parallels Kinase Inhibitor Library between growth inhibition and mRNA knockdown are not evident for all kinases targeted. In order to determine if the inhibition of growth induced by kinase knockdown was specific to prostate cancer cells, we measured the growth of LHS and MCF10A cells in response to shRNA targeting the seven kinases. LHS cells are nontumorigenic immortalized human prostate epithelial cells generated by ectopic expression of SV40 large, small T antigen, and human telomerase. MCF10A is a non-tumorigenic, spontaneously immortalized breast epithelial cell line. In general, shRNA directed against the kinases had minimal effect on LHS and MCF10A cell growth, suggesting selectivity towards prostate cancer cells. The knockdown of kinase message in LHS and MCF10A cells was variable. In LHS cells, MAP3K11 was effectively knocked down and PSKH1; however the knockdown was inefficient for the other kinases. In MCF10A cells, CIT was inhibited and PSKH1, DGKD, and GALK2 were each inhibited by approximately 50%. The inability to inhibit kinase expression to a similar extent as in LNCaP, C4-2B, and CWR22Rv1 cells, complicates interpreting the importance of these kinases in normal cell growth and survival. However, all six kinases were knocked down in at least one of the normal cell lines tested. Thus, these results are consistent with there being selectivity for targeting these kinases in cancer cells over normal cells. Since the AR is a major regulator of prostate cancer cell growth, we wanted to determine if any of the six selected kinases might affect growth through regulating the AR transcriptome. To examine the effect of kinase knockdown on AR target gene transcription, qPCR was used to measure transcript levels of two AR target genes, TMPRSS2 and SGK, in LNCaP and C4-2B cells with two independent shRNAs used to inhibit kinase expression. We examined transcription of these genes at 2 and 24 hours to evaluate the effect of kinase knockdown on the immediate-early response and steady-state levels of AR transcriptional activity. Statistical analysis indicates that there was no effect of hormone dose on the ability of kinase knockdown to affect AR transcription; kinase knockdown altered transcription equivalently, or had no effect, at each androgen dose. Maintenance of androgen induction in pLKO was observed in all analyzed experiments. Reported in Table 1 are the statistically significant changes in AR transcription of TMPRSS2 and SGK in response to kinase knockdown by two independent shRNAs at 2 and 24 hours post three different androgen dose treatments. Both shRNAs had to alter gene transcription significantly in the same direction for reporting in the table. There was no consistent decrease in AR transcriptional activity in response to knockdown of the six kinases across both cell lines, AR target genes examined, and the two time points tested.