Figure 4.

Treatment with the Zn²⁺ chelator TPEN reduces viability for PC3 and C4-2 cells and TPEN cytotoxicity is completely reversed by exogenous Zn²⁺. (A) Reduced viability upon treatment with the indicated TPEN concentration. (B) Expanded scale differentiates sensitivity of PC3 and C4-2 cells to TPEN cytotoxic effects. (C) Rescue of TPEN cytotoxicity with exogenous ZnSO₄ at the indicated concentration relative to TPEN (6 μM) and with the delay indicated. (D) NaPy but not DTPA displays rapid effects. Treatments were as indicated in Figure 1 except for 6 h followed by 72 h in drug-free media. Statistical significance, Student’s two-tailed test: *: p<0.05. (E,F) FluoZin fluorescence for PC3 cells: (E) Control (non-treated cells); (F) Treatment with TPEN (5 μM for 4 h) with identical settings as in (E).