Abstract: ObjectiveTo investigate effects of sodium selenite on human gastric cancer SGC-7901 cell growth and hTERT expression and to explore the mechanism. MethodsSGC-7901 cells were treated with different concentrations(0μmol/L,0.5μmol/L,2.5μmol/L,5μmol/L,8μmol/L) of sodium selenite for 24 hours, 48 hours, 72 hours and 96 hours. Growth inhibition of SGC-7901 cells was detected by assay of MTT. Immunohistochemical SABC method and RT-PCR assay were used to study the changes of hTERT proteins and hTERT mRNA in SGC-7901 cells. ResultsSodium selenite significantly suppressed the growth of SGC-7901 cells. The cell growth rate reduced in a dose-and time-dependent manner. The same changes had occurred for the hTERT protein level in SGC-7901 cells. The averae absorbance (AA) of hTERT protein in SGC-7901 cells was gradually lower along time, unto 96 hour it was significantly decreased in 0.5μmol/L sodium selenite group or 2.5μmol/L sodium selenite group than that in blank control group（EM>P/EM><0.01）. It was significantly decreased in 5μmol/L, 8μmol/L sodium selenite group than in blank control group all time (EM>P/EM><0.01). RT-PCR results demonstrated there was no obvious alteration of hTERT mRNA levels after 0.5μmol/L sodium selenite treatment. hTERT mRNA levels were gradually reduced along time in 2.5μmol/L sodium selenite group, there was significantly different after 48 hours treatment in 2.5μmol/L sodium selenite group than in blank control group. hTERT mRNA levels were significantly decreased all time in 5μmol/L, 8μmol/L sodium selenite group than in blank

Key words: Sodium selenite, SGC-7901 cell, Telomerase reverse transcriptase, RT-PCR