ABSTRACT
PURPOSE: The events of cell stress and cell death are linked, with the heat shock proteins (Hsps) induced in response to stress appearing to function at key regulatory points in the control of apoptosis. The purpose of this study was to investigate the effect of arisostatins A on the Hsp70 expression and signal mechanism of its transcription. MATERIALS AND METHODS: We used natural arisostatins A produced by Actinomycete, in Caki cells. We measured the growth rate of cell using trypan blue staining, and the induction of the transcriptional levels of Hsp70 with arisostatins, which was quantified by reverse transcript-polymerase chain reaction (RT-PCR) and transiently transfecting cells with a Hsp70. The induction of the transcriptional levels of Hsp70 with arisostatins A was quantified by RT-PCR and transiently transfecting cells with a Hsp70 promoter-luciferase reporter plasmid. RESULTS: Arisostatins A-induced Hsp70 up-regulation was not prevented by the overexpression of peroxiredoxinI (PrxI), PrxII or treatment of superoxide dismutase and catalase. However, the arisostatins A-mediated expression of Hsp70 was reduced significantly in Caki cells treated by the antioxidant, N-acetylcystein. Inhibition of the Janus tyrosine kinase (JAK) activity with AG490 did not inhibit the arisostatins A-induced Hsp70 up-regulation, suggesting that JAK is not associated with the arisostatins A-mediated Hsp70 expression. The mechanism of Hsp70 induction depends on the activation of heat shock factor-1. However, arisostatins A did not effect the change in the expression levels of heat shock factor-1. CONCLUSIONS: These findings suggested that Hsp directly regulates specific stress-responsive signaling pathways, which may antagonize the signaling cascades that result in apoptosis.