Objective To investigate the effect and the mechanism of Sorcin (soluble resistancerelated calcium-binding protein )on development of drug-resistance in human gastric cancer cell line.Methods The full length Sorein cDNA was isolated by reverse transcription-polymerase chain reaction (RT-PCR).The FLAG-sorein-peDNA 3.1 plasmid was constructed by directed cloning of Sorein gene into the eukaryotie expression vector FLAG-peDNA 3.1,and was transfeeted into SGC7901 cells using liposome-mediated method.The expressions of Sorcin mRNA and protein in stable clone were detected by RT-PCR and Western blot. The intracellular concentration of Vineristine (VCR) in Sorein-transfected SGC7901 eells(SGC7901-F-Sor) and SGC7901 cells with or without Verapamil(VRP) was determined by high performance liquid chromatography(HPLC).Results The FLAG-Sorcin-peDNA3.1 plasmid vector was constructed successfully by DNA recombination and was transfected into SGC7901 cells.RT-PCR and Western blot analysis revealed that the expressions of Sorcin mRNA and the protein were up-regulated in SGC7901 F-Sor cells.Compared to the parent SGC7901 cells,the concentration of VCR in SGC7901-FSor cells was decreased by 76.89%,but it was increased by 2.41 times when treated with VRP.Conclusions Overexpression of Sorcin in SGC7901 cells results in decreasing concentration of VCR,which indicate that Sorcin may play a role in drug-resistance of SGC7901 cells by regulating the transference of chemotherapy drugs.The effect of Sorcin can be reversed by VRP.