Sox2 is known as the undifferentiated cell marker. Recent studies have shown that Sox2 may also be involved in the maintenance of cancer stem cells (CSCs) in skin and bladder cancers. In this study, we aimed to clarify the role of Sox2 in colorectal CSCs. Sox2 expression was measured in colon cancer cells and colorectal clinical samples by qRT-PCR and western blot analysis. To visualize the active Sox2 mRNA production, we generated a Sox2 promoter-dependent DsRed fluorescence emission system. Colon cancer cell lines and colorectal tumor tissues generally expressed the Sox2 protein. Knockdown of Sox2 by siRNA led to increased proliferative activity in Caco2 cells. Kaplan-Meier survival curves showed that the group with high Sox2 mRNA expression had a worse prognosis for relapse-free survival (RFS) than the low expression group (P = 0.045, median follow-up 60.0 months). Time-lapse image analysis revealed that most DsRed⁺ cells exhibited typical asymmetric cell division and had higher CSC marker expressions. The DsRed⁺ cells exhibited chemoresistance and they grew slower in vitro, yet they established rather larger tumors in vivo. Our data suggest that Sox2 may be a potential biomarker for colorectal CSCs.

中文翻译：

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Sox2与大肠癌的癌干样特性有关。

Sox2被称为未分化的细胞标记。最近的研究表明，Sox2也可能参与皮肤癌和膀胱癌中癌症干细胞（CSCs）的维持。在这项研究中，我们旨在阐明Sox2在结直肠CSC中的作用。通过qRT-PCR和Western印迹分析测量了结肠癌细胞和结肠直肠临床样品中的Sox2表达。为了可视化主动Sox2 mRNA的产生，我们生成了一个依赖Sox2启动子的DsRed荧光发射系统。结肠癌细胞系和结肠直肠肿瘤组织通常表达Sox2蛋白。siRNA抑制Sox2导致Caco2细胞增殖活性增加。Kaplan-Meier生存曲线显示，Sox2 mRNA高表达组的无复发生存期（RFS）比低表达组的预后更差（P = 0.045，中位数随访60.0个月）。延时图像分析显示，大多数DsRed⁺细胞表现出典型的不对称细胞分裂，并具有较高的CSC标记表达。DsRed ⁺细胞表现出化学抗性，在体外生长较慢，但在体内却形成了较大的肿瘤。我们的数据表明，Sox2可能是结直肠CSCs的潜在生物标志物。