[Multidrug resistant effect of alternative splicing form of MAD2 gene-MAD2beta on human gastric cancer cell].

Objective: To study the effect of alternative splicing form -MAD2beta of mitotic arrest deficient protein 2 (MAD2) on the formation of multidrug resistance in human gastric adenocarcinoma cell SGC7901.

Methods: RNA was extracted from a multidrug resistance cell line SGC7901/ADR. The full-length MAD2beta cDNA was obtained by RT-PCR and cloned into the pUCm-T vector, and then recombined into the eukaryotic expression vector pcDNA3.1 in forward direction. Subsequently, pcDNA3.1/MAD2beta vectors were then transfected into SGC7901 cells by lipofectamine. Sensitivity to drug was detected by MTT assay. Cell cycle alteration and intracellular fluorescence intensity were determined by FACS.

Results: A fragment of 0.53 Kb was obtained and confirmed by DNA sequencing which was a new alternative splicing form of MAD2 named as MAD2beta. pcDNA3.1/MAD2beta transfected SGC7901 cells (SGC7901/MAD2beta) were more resistant to ADR, VCR and MMC than the control cells (SGC7901/pcDNA3.1), and also ADR fluorescence intensity of SGC7901/MAD2beta cells was lower (P < 0.05) than that of SGC7901/pcDNA3.1 cells.

Conclusion: MAD2beta could increase the multidrug resistance of SGC7901 cell line.