Rapid polymerase chain reaction assay to detect variation in the extent of gene-specific damage between cisplatin- or VP-16-resistant and sensitive lung cancer cell lines.

We previously established a rapid and facile polymerase chain reaction (PCR)-stop assay for quantitation of specific gene damage in very small numbers of cells. The present study investigated whether the PCR-stop assay was able to detect variation in the extent of DNA damage in transcribed active genes between cisplatin- or VP-16-resistant and sensitive cells. The assay demonstrated that about twice as much genetic damage occurs in PC-9 cells than in cisplatin-resistant PC-9/CDDP cells following cisplatin exposure and about 4.6 times more damage occurs in H69 than in VP-16-resistant H69/VP cells following VP-16 exposure. These results show that DNA damage, as detected by PCR-stop assay, correlates with cytotoxicity. In conclusion, the PCR-stop assay could be useful in detecting variation in DNA damage in specific genes.