BACKGROUNDTo study the effects of extraneous p53 antisense RNA on malignant growth and sensitivity to cisplatin of human lung cancer cell line.

METHODS801D cell line with p53 deletion and mutation at 248 codon was selected as a parent cell line. An 1.8 kb human p53 full length cDNA was inserted into a mammalian expression vector PEGFP to construct a p53 antisense RNA recombined plasmid PEGFP-p53(AS) and GFP gene at plasmid was a report gene to monitor extraneous gene expression. The extraneous gene was detected by PCR. The p53 mutation protein was examined by immunohitochemical stain of p53 monoclonal antibody. The inhibition growth efficacy of extraneous p53 in vitro was determined by clonogenic survival assay. Sensitivity of cells to cisplatin was examined with MTT assay. FCM analysis was performed to measure the effect of p53 antisense RNA on cell cycle.

RESULTSTwo cell lines, PEGFP-p53(AS)-801D and PEGFP-801D, were established after transfection of 801-D cells by lipofection and selection. Presence of extraneous p53 gene in PEGFP-p53(AS)-801D was proved by PCR and expression of extraneous p53 was estimated when green fluorescence in those cells was found out under the fluorescent microscopy. Mutated p53 protein in parent cell line 801D was positive and in PEGFP-p53(AS)-801D was negative with immunochemical stain. The inhibition rate of colony formation was 61% for PEGFP-p53(AS)-801D (P < 0.001). The sensitivity of PEGFP-p53(AS)-801D cells to cisplatin was increased. FCM analysis showed that the cell line was arrested at G1 phase.

CONCLUSIONSp53 mutation at 248 code plays an important role on malignant growth and resistance to cisplatin of human lung cancer cell line 801D. Malignant growth of cells with p53 deletion and mutation at 248 codon can be inhibited by extraneous p53 antisense RNA, and simultaneously the sensitivity to cisplatin is also increased.