Biological characteristics of highly tumorigenic CD44+CD133+ subpopulation of laryngeal carcinoma cells / 中华肿瘤杂志

ABSTRACT

<p><b>OBJECTIVE</b>To separate the cell subpopulation with high tumorigenic ability and study the biological characteristics of this subpopulation in laryngeal carcinoma cells.</p><p><b>METHODS</b>Human laryngeal carcinoma cells were obtained by primary tissue culture technique. CD44 and CD133 molecules were used as markers to isolate the CD44(+), CD133(+), CD44(+)CD133(+) and CD44(+)CD133(-) cell subpopulations from the laryngeal carcinoma cells by flow cytometry. A nude mouse tumor xenograft model was developed for the study of the tumorigenic effects of the different cell populations. 1 x 10(6), 1 x 10(5), 1 x 10(4) and 1 x 10(3) cells were injected into the left flank of the mice, respectively. The mice were observed for palpable tumor formation and were sacrificed at 4 weeks later to assess the tumor formation rate, tumor volume and tumor weight. Boyden chamber migration assay was used to determine the migration ability and immunochemistry was used to detect the expression of stem cell antigen SCA-1 and beta1-integrin. Semi-quantities RT-PCR and Western blot analysis were performed to detect the expression level of Bmi-1 in the different cell subpopulations.</p><p><b>RESULTS</b>The growth of subcutaneous tumors in nude mice showed that a tumor can be generated with 1 x 10(3) CD44(+)CD133(+) cells. When the same dose of 1 x 10(6) CD44(+)CD133(+) cells was injected into the mice, both the average weight and volume of the tumors were significantly higher than those generated from other cell subpopulations. Boyden chamber migration assay showed that the invasion ability of CD44(+)CD133(+) cells was significantly higher than that of other cell subsets. The results of immunochemical analysis showed an abundant expression of stem cell antigen SCA-1 and beta1-integrin in the CD44(+)CD133(+) cells. Semi-quantitative RT-PCR and Western blot analysis provided strong evidence that the Bmi-1 expression in CD44(+)CD133(+) and CD133(+) cells was very significantly higher than that in CD44(+), CD44(+)CD133(-) and control cells (P < 0.01).</p><p><b>CONCLUSION</b>Our findings demonstrate that CD44(+)CD133(+) subset cells in laryngeal carcinoma posses some biological characteristics of tumor stem cells, which may be the original cells of laryngeal carcinoma and may become a new target of tumor therapy.</p>