The efficacy of ZHPV16 E7 affitoxin384 in vitro. SiHa, CaSki, HeLa and A375 cells were treated with different concentrations of ZHPV16 E7 affitoxin384 for different time periods. Cell viability was measured using CCK-8 assay. Cells treated with Zwt affitoxin were used as control. (A) SiHa cells were treated with indicated concentrations of ZHPV16 E7 affitoxin384 or Zwt affitoxin for 72 h. (B) CaSki cells were treated with indicated concentrations of ZHPV16 E7 affitoxin384 or Zwt affitoxin for 72 h. Compared to the control group, cell viability decreased with the increase of concentration of ZHPV16 E7 affitoxin384. (C) SiHa, CaSki, HeLa and A375 cells were treated with 2 μM of ZHPV16 E7 affitoxin384 for indicated time periods. (D) SiHa, CaSki, HeLa and A375 cells were treated with 2 μM of ZHPV16 E7 affitoxin384 or Zwt affitoxin for 72 h. ZHPV16 E7 affitoxin384 significantly reduced the viability of SiHa and CaSki cells during the indicated time periods, whereas HeLa and A375 cells treated with the same concentration of ZHPV16 E7 affitoxin384 remained fully viable during the indicated time periods. Zwt affitoxin had no effect on any kinds of cells. (E) SiHa cells were treated with indicated concentrations of ZHPV16 E7 affitoxin384 or Zwt affitoxin for 72 h. (F) CaSki cells were treated with indicated concentrations of ZHPV16 E7 affitoxin384 or Zwt affitoxin for 72 h. The IC50 values were calculated using GraphPad Prism software. Data are given as mean ± SD (n=3). **P <0.01 versus the control group. The IC50 values of ZHPV16 E7 affitoxin384 were respectively 3.7×10-5 and 1.3 ×10-4 times lower than that of Zwt affitoxin.