Department of Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan.
Cell Transplant. 2010;19(6):857-64. doi: 10.3727/096368910X508988. Epub 2010 Jun 29.
Worldwide, colorectal cancer is the third most common type of cancer affecting both sexes. It has been proposed that a small subset of cancer cells (cancer stem cells) within each tumor is able to initiate tumor growth. In 2007, two research groups simultaneously identified a colon cancer stem cell population in human tumors by the use of CD133 expression. In the present study, we used a human colon cancer cell line, SW620, to analyze the cancer stem cell-like characteristics of CD133(+) cells in vitro and in vivo. In vitro, CD133(+) SW620 cells had a higher proliferative capacity, were more irradiation- and chemotherapy-resistant, and had a higher expression of β-catenin compared with CD133(-) cells. Injections of either CD133(+) or CD133(-) cells into the skin or rectal mucosa of NOD/SCID mice led to tumors; however, injection of CD133(+) cells resulted in the formation of larger tumors. Tumors derived from injections of CD133(-) cells did not contain any CD133(+) cells, whereas tumors derived from injections of CD133(+) cells did contain CD133(+) cells, suggesting self-renewing capability. However, the proportion of CD133(+) cells in the newly formed tumors in vivo was lower than the proportion of CD133(+) cells in vitro. In conclusion, the human colon cancer cell line, SW620, contains both CD133(+) and CD133(-) phenotypes, and the CD133(+) phenotype has characteristics consistent with those of cancer stem cells.
在全球范围内，结直肠癌是男性和女性都受到影响的第三大常见癌症类型。有人提出，每个肿瘤中的一小部分癌细胞（癌症干细胞）能够启动肿瘤生长。2007 年，两个研究小组通过 CD133 表达同时在人类肿瘤中鉴定出了结肠癌干细胞群体。在本研究中，我们使用人结肠癌细胞系 SW620 来分析 CD133(+)细胞在体外和体内的类癌干细胞特征。在体外，CD133(+)SW620 细胞具有更高的增殖能力，对辐射和化疗的抗性更强，并且β-连环蛋白的表达更高与 CD133(-)细胞相比。将 CD133(+)或 CD133(-)细胞注入 NOD/SCID 小鼠的皮肤或直肠黏膜中会导致肿瘤形成；然而，注入 CD133(+)细胞会导致更大的肿瘤形成。源自 CD133(-)细胞注射的肿瘤不含有任何 CD133(+)细胞，而源自 CD133(+)细胞注射的肿瘤则含有 CD133(+)细胞，表明具有自我更新能力。然而，在体内新形成的肿瘤中 CD133(+)细胞的比例低于体外的 CD133(+)细胞的比例。总之，人结肠癌细胞系 SW620 既包含 CD133(+)表型又包含 CD133(-)表型，并且 CD133(+)表型具有与癌症干细胞特征一致的特征。
