The molecular mechanism of "thymineless" death induced by 5-fluorodeoxyuridine or trifluorothymidine, in androgen-independent rat prostatic adenocarcinoma AT-3 cells was investigated. Fragmentation of genomic DNA into discrete multiples of a nucleosomal unit (i.e. 180bp subunit) and induction of expression of TRPM-2, a programmed cell death-associated gene, temporally correlated with the activation of programmed cell death in this system. In contrast, killing of AT-3 cells by osmotic lysis, or membrane-targeted metabolic inhibitors results in neither the stereotypic DNA fragmentation into nucleosomal oligomers nor the elevation of TRPM-2 mRNA levels but to non-specific biochemical changes characteristic of necrosis. These results suggest that androgen-independent prostatic cancer cells retain a major portion of the programmed cell death cascade which can be activated by non-androgen ablative cytotoxic drugs that induce "thymineless" death.