[Detection of drug resistant-gene in cisplatin-resistant colon carcinoma cells by RT-PCR assay. I].

Expression of the TS and DNA polymerase beta genes as a drug resistant-gene were compared with the human colon carcinoma cell line HCT8S and a subline that was 4.5 fold resistant to cisplatin. Resistant cells (HCT8DDP) exhibited 3.4 fold and 2.5 fold increase in mRNA for both TS and DNA polymerase beta gene when compared with the parent cells by Northern blotting analysis, respectively. The RT (reverse transcription)-PCR (polymerase chain reaction) method has been modified to quantify a sequence of a drug resistance gene. This method exhibited greater sensitivity than conventional methods (Northern blotting analysis), requiring less than 1 fetogram of mRNA from cell lines. The RT-PCR assay could be an effective device in the early detection of resistance to chemotherapy.