Yan Xiaodong, Han Dali, Chen Zhiqiang, Han Chao, Dong Wei, Han Li, Zou Lei, Zhang Jianbo, Liu Yan, Chai Jie
Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Capital Medical University, Beijing, 100069 China.
Department of Radiation Oncology, Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, 250117 Shandong Province China.
Cancer Cell Int. 2020 Oct 15;20:505. doi: 10.1186/s12935-020-01544-w. eCollection 2020.
Cancer stem cells (CSCs) play an important role in tumor invasion and metastasis. CD44 is the most commonly used marker of CSCs, with the potential to act as a determinant against the invasion and migration of CSCs and as the key factor in epithelial-mesenchymal transition (EMT)-like changes that occur in colorectal cancer (CRC). Runt-related transcription factor-2 (RUNX2) is a mesenchymal stem marker for cancer that is involved in stem cell biology and tumorigenesis. However, whether RUNX2 is involved in CSC and in inducing EMT-like changes in CRC remains uncertain, warranting further investigation.
We evaluated the role of RUNX2 in the invasion and migration of CRC cells as a promoter of CD44-induced stem cell- and EMT-like modifications. For this purpose, western blotting was employed to analyze the expression of differential proteins in CRC cells. We conducted sphere formation, wound healing, and transwell assays to investigate the biological functions of RUNX2 in CRC cells. Cellular immunofluorescence and coimmunoprecipitation (co-IP) assays were performed to study the relationship between RUNX2 and BRG1. Real-time quantitative PCR (RT-qPCR) and immunohistochemistry (IHC) were performed to analyze the expressions of RUNX2, BRG1, and CD44 in the CRC tissues.
We found that RUNX2 could markedly induce the CRC cell sphere-forming ability and EMT. Interestingly, the RUNX2-mediated EMT in CRC cell may be associated with the activation of CD44. Furthermore, RUNX2 was found to interact with BRG1 to promote the recruitment of RUNX2 to the CD44 promoter.
Our cumulative findings suggest that RUNX2 and BRG1 can form a compact complex to regulate the transcription and expression of CD44, which has possible involvement in the invasion and migration of CRC cells.
癌症干细胞（CSCs）在肿瘤侵袭和转移中起重要作用。CD44是CSCs最常用的标志物，有可能作为抵抗CSCs侵袭和迁移的决定因素，也是结直肠癌（CRC）中发生的上皮-间质转化（EMT）样变化的关键因素。 runt相关转录因子2（RUNX2）是一种癌症间充质干细胞标志物，参与干细胞生物学和肿瘤发生。然而，RUNX2是否参与CSC以及是否在CRC中诱导EMT样变化仍不确定，值得进一步研究。
我们评估了RUNX2作为CD44诱导的干细胞样和EMT样修饰的促进因子在CRC细胞侵袭和迁移中的作用。为此，采用蛋白质免疫印迹法分析CRC细胞中差异蛋白的表达。我们进行了成球、伤口愈合和Transwell实验，以研究RUNX2在CRC细胞中的生物学功能。进行细胞免疫荧光和免疫共沉淀（co-IP）实验，以研究RUNX2与BRG1之间的关系。进行实时定量PCR（RT-qPCR）和免疫组织化学（IHC）实验，以分析RUNX2、BRG1和CD44在CRC组织中的表达。
我们发现RUNX2可显著诱导CRC细胞的成球能力和EMT。有趣的是，RUNX2介导的CRC细胞EMT可能与CD44的激活有关。此外，发现RUNX2与BRG1相互作用，促进RUNX2募集到CD44启动子。
我们的累积研究结果表明，RUNX2和BRG1可以形成紧密复合物来调节CD44的转录和表达，这可能参与CRC细胞的侵袭和迁移。
