[Abnormal expression of caspase8,bcl-2 and cytochrome C in drug resistant lung cancer cell].

OBJECTIVE: To investigate the relations between the chemotherapy resistance in lung cancer cell (LCC) A549 and the expression of apoptosis protein including caspase8, bcl-2 and cytochrome C and bcl-2 mRNA. METHODS: Bcl-2 mRNAs of sensitive A549 cell (A549S) and drug-resistant A549 cell (A549R) cultured were amplified by reverse transcription polymerase chain reaction (RT-PCR), and the expressions in the two strains were compared by AG electrophoresis, with beta-actin as control. The caspase8, bcl-2 and cytochrome C proteins in the two strains were measured and assessed by Western Blot. RESULTS: The caspase8 and cytochrome C protein expressions were higher in A459S than in A549R (P<0.05). The bcl-2 protein expression was lower in A459S than in A549R (P<0.05). But there was no significant difference between the level of bcl-2 mRNA expression in strain A549S (8.74+/-1.81) and that in strain A549R (10.29+/-2.92) (P>0.05). CONCLUSION: The upregulation of the bcl-2 protein could depress the caspase8 and cytochrome C protein expression and so might be one of the reasons for drug resistance in lung cancer cell, but the upregulation might happen at the level of translation or thereafter not at the mRNA level.