ABSTRACT
Objective To study the tumorigenetic characteristics of side population (SP) cells and their exsistence in gastric cancer cell lines and tissues.Methods Flow cytometry and the DNA-binding dye Hoechst 33342 staining were used to analyze sorted SP cells in 3 gastric cancer cell lines(SGC-7901,BCIC-823 and MKN28).SP cells and non-SP cells(main population cells)isolated from SGC-7901 cell line weresubcutaneously injected into 36 nude mice with 500,5000 or 50 000 cells per mouse,respectively.Thetumorigenity was observed 8 weeks after injection.The expression of ATP-binding cassette sub-family Gmember 2(ABcG2)mRNA in three gastric cell lines and its level in gastric cancer tissues were detected by real-time PCR and immunostaining.respectively.Results The proportion of SP cells was accounted for 1.0%in SGC-7901 cells and 1.3%in BGc-823 cells.No SP cell was found in MKN28 cells.As low as 500 SP cells or 50 000 non-SP cells could initiate tumors in mice.The expression of ABcG2 mRNA was higher in SGC-7901(O.162)and BGC-823(O.096)cell lines than that in MKN28 cell line(0.005).The value of AtCG2 mRNA/beta-aetin mRNA and protein in gastric cancer tissues was different from those in gastritis tissues.Condasimm SP cells have strong ability of tumorigenesis compared with non-SP cells.The expression of ABCG2 is found in gastric cancer tissues and part gastritis tissues.The more the SP cells in gastric cell lines,the higher the expression of ABCG2.