Cancer Research Institute, Xiang-Ya School of Medicine, Central South University, Key Laboratory for Carcinogenesis of Chinese Ministry of Health, Key Laboratory for Carcinogenesis and Cancer Invasion of Chinese Ministry of Education, Changsha, Hunan 410078, PR China.
Oncol Rep. 2012 Apr;27(4):1177-87. doi: 10.3892/or.2011.1618. Epub 2011 Dec 30.
Tumor stem cells are a small subset of tumor cells with the ability of self-renewal and differentiation and are regarded as a cause of tumor growth and recurrence. Previously we have shown that stem-like label-retaining cells (LRCs) can be detected in nasopharynx, tongue, esophagus and xenograft tumors formed by nasopharyngeal carcinoma (NPC) cell lines (5-8F, 6-10B and TMNE). The present study aimed to identify ABCG2⁺ cells in 5-8F NPC cells and compare their tumorigenic potential with ABCG2⁻ cells, expecting that we can obtain insight into the mechanism of the differential phenotypes of ABCG2⁺ and ABCG2⁻ cells. By using magnetic cell sorting (MACS) method, we isolated ABCG2⁺ cells and ABCG2⁻ cells from 5-8F cells. Among these two subpopulations and unsorted 5-8F cells, the rate of ABCG2⁺ cells at G1 phase was highest, while the rate of ABCG2⁻ cells at S phase was highest, indicating that ABCG2⁺ cells were mostly quiescent. However, ABCG2⁺ cells showed lower cloning efficiency and tumorigenicity than ABCG2⁻ cells. We also used Affymetrix U133 plus 2.0 human whole genome expression chip to identify the gene expression profile of ABCG2⁺ and ABCG2⁻ cells and found that both subpopulations expressed some stem cell associated genes, e.g., PSCA, ABCG2 and ALPI were expressed in ABCG2⁺ cells, and K19, integrin α6, integrin β4, CD44 and K14 were expressed in ABCG2⁻ cells, suggesting there were stem cells in both ABCG2⁺ and ABCG2⁻ cells. Our data demonstrated that there exist ABCG2⁺ cells in NPC cells, but ABCG2 alone is not sufficient for isolating cancer stem cells in 5-8F NPC cells.
肿瘤干细胞是肿瘤细胞中的一小部分，具有自我更新和分化的能力，被认为是肿瘤生长和复发的原因。之前我们已经证明，在鼻咽、舌、食管和鼻咽癌（NPC）细胞系（5-8F、6-10B 和 TMNE）形成的异种移植肿瘤中，可以检测到干细胞样标记保留细胞（LRCs）。本研究旨在鉴定 5-8F NPC 细胞中的 ABCG2⁺细胞，并比较其与 ABCG2⁻细胞的致瘤潜力，期望我们能够深入了解 ABCG2⁺和 ABCG2⁻细胞的差异表型的机制。通过使用磁性细胞分选（MACS）方法，我们从 5-8F 细胞中分离出 ABCG2⁺细胞和 ABCG2⁻细胞。在这两个亚群和未分选的 5-8F 细胞中，G1 期 ABCG2⁺细胞的比例最高，而 S 期 ABCG2⁻细胞的比例最高，表明 ABCG2⁺细胞大多处于静止状态。然而，与 ABCG2⁻细胞相比，ABCG2⁺细胞的克隆效率和致瘤性较低。我们还使用 Affymetrix U133 plus 2.0 人类全基因组表达芯片来鉴定 ABCG2⁺和 ABCG2⁻细胞的基因表达谱，发现这两个亚群都表达了一些与干细胞相关的基因，例如，PSCA、ABCG2 和 ALPI 在 ABCG2⁺细胞中表达，而 K19、整合素 α6、整合素 β4、CD44 和 K14 在 ABCG2⁻细胞中表达，表明 ABCG2⁺和 ABCG2⁻细胞中都存在干细胞。我们的数据表明，NPC 细胞中存在 ABCG2⁺细胞，但仅 ABCG2 不足以分离 5-8F NPC 细胞中的癌症干细胞。
