Animal studies were carried out in the animal features of The University of Kansas Clinic with strict adherence to the rules of the IACUC Animal Welfare Committee of KUMC. KU174 displays vast activity across the NCI60 cancer cell panel Human tumor cell lines from the panel were used to evaluate KU174 activity across cancers. That display unmasked that OSI-420 Desmethyl Erlotinib KU174 exhibits extensive task across numerous cancer cell lines. Notably KU174 is apparently especially effective across the melanoma cell lines and was also cytotoxic in the multi drug resistant ovarian adenocarcinoma cell line. Within the prostate cancer cell lines, PC 3 and DU145, KU174 was cytostatic in the single dose of 10 uM with values of 0. 46 and 51. 79, respectively. Furthermore, assessment of the LNCaP LN3 androgen dependent prostate cancer cell line in anti-proliferative assays demonstrate a GI50 of 128 nM. Based on prior publications in prostate cancer using an earlier Inguinal canal analogue, F 4, we chose to focus on the characterization of KU174 in LNCaP LN3 cell lines and the PC3 MM2 to help expand comprehend its mechanism of action and effects on Hsp90. KU174 demonstrates somewhat distinct cytotoxicity, to cancer cells compared to normal renal cells KU174 induced cytotoxicity in prostate cancer cells was assessed by trypan blue exclusion. PC3 MM2 cells dosed with KU174 for 24 hours demonstrated a dosedependent decrease in stability which range from 25 percent. The parent substance NB, at 500 uM, triggered a stability of 755-nm, indicating KU174 manifests a 10 50 fold increase in effectiveness compared to its parent molecule. No reduction in cell viability was seen with 17 AAG at 10 uM which is consistent with previously published order BMN 673 data showing no cytotoxicity in either cell line at levels as high as 100 uM. Comparing total cells to the time zero cell density unmasked that 0. 1 uM KU174 can be as cytostatic as 10 uM 17 AAG. These data show that KU174 is cytotoxic at higher concentrations and cytostatic at low relative concentrations. In the LNCaP LN3 cell line, the same trend was observed with respect to cytotoxicity with KU174 being roughly three to five fold more potent. Furthermore, PC3 MM2 cells dosed with KU174 for only six hours led to a similar cytotoxic reaction as seen at 24 hours. However, regular human renal proximal tubule epithelial cells dosed with KU174 for 6 hours showed no loss in stability, providing evidence that KU174 is somewhat selective for both prostate cancer cell lines. The RPTEC was chosen because the normal cell line based on previous reports that Hsp90 inhibitors have a 100-fold lower affinity in normal cell lines in comparison to tumor cell lines. Following 24 hour KU174 treatment, approximately 500-million of the cells remain viable within the 50 uM range. Thus, the mode of cytotoxicity was evaluated between 24 and 48 hours of treatment by flow cytometry.