Objective   To construct the plasmids containing short hairpin RNA of Hsp70 for knockdown of the expression of Hsp70 and investigate the effects on cell proliferation in gastric cancer cell line.    Methods   We designed two pairs of reversed duplicate sequence and a pair of reversed duplicate mismatched sequence along with a negative control

which were inserted into contrivance promotor U6 of pTZU6+1 to generate recombinant plasmids

the phsp1-siRNA

phsp2-siRNA and phsp3-siRNA

respectively. The recombinant plasmids were then transfected into human gastric carcinoma cell SGC-7901 for the detection of Hsp70 expression

respectively. The inhibition of cell proliferation was examined by AlamarBlue method.     Results   Electrophoretic analysis and sequencing showed that the recombinant plasmids of phsp1-siRNA and phsp2-siRNA were successfully constructed. After the recombinant plasmids of phsp-siRNA were transfected into the cells of SGC-7901

the expressions of Hsp70 in the phsp1-siRNA and phsp2-siRNA group were down-regulated more significantly than those in the control ones

and the inhibition rate was higher than that in the control ones through AlamarBlue.     Conclusion   The constructed recombinant plasmids of phsp1-siRNA and phsp2-siRNA can efficiently suppress the expression of Hsp70 in SGC-7901 cells

which may be a basic foundation for the genetic therapy of gastric cancer in the future.