Triptolide Inhibits PCa Cells Proliferation Figure 1. Triptolide and Celastrol inhibited cell growth and induced cell death in PCa cell lines. (A) and (B) The chemical structure of Triptolide (A) and Celastrol (B), respectively. (C), (D), (E) and (F) PCa cells were treated with indicated doses of Triptolide or Celastrol, viable cell numbers were counted every day for 6 days. All assays were performed in triplicate, and data shown are mean 6 SD of three independent PLoS ONE | www.plosone.org 3 May 2012 | Volume 7 | Issue 5 | e37693