FIG. 5.

Effects of ZVAD.fmk treatment on cell morphological changes following CVB3 infection or BPD-MA and light treatment of HeLa cells. HeLa cells were treated with ZVAD.fmk at 0 to 200 μM and then infected with CVB3 or treated with BPD-MA and light. At 10 h postinfection, caspases were processed and substrates were cleaved in virus-infected cells, and at 2 h post-light treatment, caspases were processed and substrates were cleaved in BPD-MA-treated cells. Note the difference in the morphological appearances of the CVB3-infected and photodynamically treated HeLa cells. CVB3-infected HeLa cells appeared rounded, with smooth cell surfaces, while the HeLa cells treated with BPD-MA and light displayed extensive membrane blebbing and shrinkage, with cellular heterogeneity. At higher concentrations of ZVAD-fmk, the morphological changes produced by BPD-MA and light treatment were inhibited, and the cell appearance was similar to that of control HeLa cells (BPD-MA treated plus no light). In CVB3-infected HeLa cells, the morphological changes were not inhibited with increasing concentrations of ZVAD.fmk, suggesting that the morphological alterations were independent of caspase processing and cleavage of substrates.