OBJECTIVETo investigate the correlations between the resistant degree of Tca8113 agaist carboplatin and the expression of excision repair cross-complementation 1 (ERCC-1).

METHODSTca8113 cells were exposed in the carboplatin solutions of gradually increasing concentration. Cancer cells were divided into six experimental groups and a control group. In the course of culture, the half inhibitory concentration (IC(50)) of each groups were detected by methyl thiazolyl tetrazolium (MTT). The expressions of ERCC-1 at mRNA and protein level were detected by reverse transcription polymerase chain reaction (RT-PCR) and Western blotting.

RESULTSWith the increase of drug resistance, the expression of ERCC-1 increased gradually at mRNA level (control group: 0.84 ± 0.06, group 1: 0.96 ± 0.06, group 2: 1.07 ± 0.11, group 3: 1.13 ± 0.09, group 4: 1.19 ± 0.08, group 5: 1.29 ± 0.07, group 6: 1.47 ± 0.08), values between neighboring or interval groups have significant differences (P < 0.05); the expression of ERCC-1 increased gradually at protein level (control group: 0.69 ± 0.05, group 1: 0.86 ± 0.04, group 2: 1.01 ± 0.04, group 3: 1.24 ± 0.09, group 4: 1.44 ± 0.14, group 5: 1.56 ± 0.19, group 6: 1.88 ± 0.22), values between neighboring or interval groups have significant differences (P < 0.05). The gradually increasing RT-PCR gray values were related to the gradually increasing IC(50) in all groups (r = 0.91, P < 0.01), and the gradually increasing western blotting gray values were also related to the gradually increasing IC(50) in all groups (r = 0.88, P < 0.01).

CONCLUSIONSThe high expression of ERCC-1 may become an indicator of Tca8113 resisting carboplatin. This might provide a potential target to reverse tongue squamous cell cancer (Tca8113) that has resistance to carboplatin.