Another of our important findings is that celastrol's actions upon cell cycle and HSP90 clients can be reversed by pre-treatment with thiol-containing agents, such as NAC or GSH, but not by GSSG or non-thiol reducing agents like Vit C. Our findings agree with previous investigations by Trott et al, who reported that celastrol induced heat shock response- and antioxidant response-inducible transcripts in RKO human colorectal carcinoma cells, these effects decreasing upon incubation with 250 μM DTT [9]. This evidence concerns the gene HSP90AA1 and colorectal carcinoma.