CXCR4 positive cells from Lewis lung carcinoma cell line have cancer metastatic stem cell characteristics

Abstract

There is increasing evidence that cancer stem cells contribute to the initiation and propagation of many tumor. Therefore, to find out and identify the metastatic tumor stem-like cells in Lewis lung cancer cell line (LLC), the expression of CXCR4 was measured in LLC by flow cytometry and observed by laser scanning confocal microscope (LSCM). After the CXCR4(+) LLC cell was isolated from LLC by magnetic cell sorting, its properties were evaluated by their tumorigenic and metastatic potentials. CXCR4(+) cells were counted for 0.18% of the total number of LLC, and immunofluorescent staining cells were identified by LSCM. CXCR4(+) LLC suspension cultured in a serum-free medium, cell spheres expressed a high level of Sca-1. The chemotherapy sensitivity to cisplatin of CXCR4(+) LLC was lower than that of CXCR4(-) LLC. The expression of ABCG2 and IGF1R mRNA in CXCR4(+) LLC was higher than that in CXCR4(-) LLC (P < 0.01). Most of CXCR4(+) LLC cells were close to vascular endothelial cells, aberrant vasculature around it was forming. The expression of VEGF and MMP9 mRNA in CXCR4(+) LLC was higher than that in CXCR4(-) LLC (P < 0.05), the microvessel density (MVD) of CXCR4(+) subsets growing were higher than that of CXCR4(-) subsets growing tumor tissue (P < 0.01). The tumor size, volume, and metastatic foci in the lungs of CXCR4(+) LLC was significantly higher than that in CXCR4(-) LLC (P < 0.001). Similarly, elevated expression of MMP9 and VEGF was also positively associated with CXCR4(+) LLC. Our results demonstrated that CXCR4(+) cells from Lewis lung carcinoma cell line exhibit cancer metastatic stem cell characteristics.