Figure 4. Triptolide triggers programmed cell death through HSP90β.

(A) TL exhibits cytotoxicity in HeLa cells. Luminescence cell proliferation assay was performed to determine cell viability of HeLa cells transfected with either control siRNA or HSP90β siRNA upon TL treatment for 24 hrs in different concentrations. IC₅₀ from three independent experiment was determined. Data are presented as mean ± SD (n = 3). (B) TL treatment triggers apoptosis in HeLa cells. Annexin V/PI analysis (upper) of apoptotic HeLa cells upon treatment of different concentrations of TL for 24 hrs. Western Blot analyses (lower) of cleavage PARP of HeLa cells upon 24 hrs’ TL treatment. Representative image from three independent experiment was shown. (C) Knockdown of HSP90β sensitizes TL-triggered apoptosis in HeLa cells. Annexin V/PI analysis (left) of apoptotic cells and Western Blot (right) analyses of cleavage PARP of HeLa cells transfected with control siRNA or HSP90β siRNA in the presence and absence of TL for 24 hrs. Representative image from three independent experiment was shown.