Objective  To observe the effect of CA916798 eukaryotic expression vector transfection on the growth of H446 cells in vitro and explore the role of CA916798 in the MDR of lung cancer.   Methods Total RNA was isolated from A549 cells. The ORF of CA916798 was amplified by RT-PCR

then cloned into pBluescriptⅡSK vector. After identified by restriction endonucleases digestion and sequencing

it was cloned to the expression vector: pQE-Trisystem vector. The recombinant pQE-Tri-CA916798 was transformed into E.coli DH5α

identified by double digestion of restriction endonucleases and sequencing

then transfected into H446 cells by lipofectamine method. The growth curve was plotted and the sensitivity of cell lines to the drug was detected by MTT test. The effect of CA916798 on the cell cycle was observed by flow cytometry.   Results  Fragments about 350 bp were amplified. Enzymatic digestion showed that the length was in consistence with the expected. After CDDP treatment

the growth of pQE-Tri-CA916798 transfected cells was faster than that of vector transfected cells

and the cell apoptosis decreased.    Conclusion  The eukaryotic expression vector was successfully constructed. CA916798 may play an important role in MDR of lung cancer.