Abstract: Objective To isolate the side population (SP) and non-side population (NSP) cells from A431 cells and compare their
difference in tumorigenicity in mice and the expression profiles of epithelial-mesenchymal transition (EMT) markers. Methods
A431 cells stained with Hoechst 33342 were sorted with flow cytometry. The isolated SP cells and NSP cells were inoculated
into NOD/SCID mice and the tumorigenicity of the cells was observed. EMT markers E-cadherin, β-catenin, vimentin, AXL,
and Erbb3 in the tumor tissues were detected by immuohistostaining. Results The tumors generated by SP cells were larger
than those by NSP cells in NOD/SCID mice. Compared with the tumors generated by NSP cells, the cells in the periphery of
tumors generated by SP cells showed up-regulated expressions of AXL, vimentin and β-catenin and down-regulated ERBB3
and E-cadherin. Conclusion The SP cells in A431 cells have a strong tumorigenicity and show more EMT phenotypes in
tissues.