Product Overview
PU-H71 is a potent and selective purine scaffold inhibitor of Hsp90 (Heat shock protein 90). Hsp90 is a molecular chaperone, it takes participate in a variety of cellular processes through promoting the folding, assembly and transport of its client proteins. Hsp90 is found to overexpress in many kinds of cancer cells. It serves as a protector of the oncoproteins which are also the client of Hsp90. Therefore, Hsp90 is thought to be an attractive target of the cancer therapy. The Hsp90 inhibitors found so far can be categorized into several classes according to the mechanisms. Among these, the inhibitors which bind to Hsp90 within its N-terminal ATP binding site are most explored. PU-H71 is one of this sort of inhibitors. As an inhibitor of Hsp90, PU-H71 is found to induce the degradation of Her2 through blocking the interaction of Hsp90 and Her2. In SKBr3 breast cancer cells, PU-H71 induced Her2 degradation with EC50 value of 50 nM. In MDA-MB-468 breast cancer cells, PU-H71 showed antimitotic efficacy with IC50 value of 70 nM. PU-H71 affected the growth of a serious of cancer cells with IC50 values of 50 nM, 58 nM and 100 to 300 nM in SKBr3, MDA-MB-468 and human myeloma cells (such as NCI-H929, U266 and MM-IR). Besides that, PU-H71 is found to cause cell cycle arrest through reducing the levels of CDK1 and Chk1 which are essential for the G2-M progression. PU-H71 administration significantly reduced the tumor size in mice injected with A673 tumor cells. In mice bearing MDA-MB-468 tumor xenografts, PU-H71 administration at dose of 75 mg/kg, 3 week remarkably inhibited tumor growth and proliferation by 96% and 60%, respectively. Moreover, PU-H71 is found to down-regulate some Hsp90-regulated malignancy driving proteins when treated in the animal, such as Raf-1, HER3, EGFR and PARP.