Chen Yao, Lu Xiaoqin, Gao Ling, Dean Douglas C, Liu Yongqing
Hunan Key Laboratory of Ophthalmology, Eye Center of Xiangya Hospital, Central South University, National Clinical Medical Center for Geriatric Diseases of Xiangya Hospital, Changsha, China.
Department of Medicine, James Graham Brown Cancer Center, Birth Defects Center, University of Louisville School of Medicine, Louisville, KY, USA.
Cell Oncol (Dordr). 2022 Apr;45(2):309-321. doi: 10.1007/s13402-022-00671-y. Epub 2022 Apr 11.
The mechanism underlying cancer heterogeneity and plasticity remains elusive, in spite of the fact that multiple hypotheses have been put forward. We intended to clarify this heterogeneity in uveal melanoma (UM) by looking for evidence of cancer stem cell involvement and a potential role of ZEB1 in cancer cell plasticity.
Spheroids derived from human UM cells as well as xenograft tumors in nude mice were dissected for signs of heterogeneity and plasticity. Two human UM cell lines were studied: the epithelioid type C918 cell line and the spindle type OCM1 cell line. We knocked down ZEB1 in both cell lines to investigate its involvement in the regulation of stem-like cell formation and vascularization by qRT-PCR, immunohistochemistry, flow cytometry, electrophoretic mobility shift assay (EMSA) and chromatin immunoprecipitation (ChIP) assays.
We found that a small side population (SP) in OCM1 showed stem cell-like properties such as heterogeneity, remote dissemination and nuclear dye exclusion after spheroid formation in vitro. ZEB1 regulated UM stem cell generation indirectly by promoting cell proliferation to form large size tumors in vivo and spheroid in vitro, and directly by binding to stemness genes such as TERT and ABCB1. In addition, we found that ZEB1 participates in vasculogenic mimicry system formation through the regulation of CD34 and VE-cadherin expression.
From our data we conclude that cancer stem cells may contribute to UM heterogeneity and plasticity and that ZEB1 may play a regulatory role in it.
尽管已经提出了多种假说，但癌症异质性和可塑性的潜在机制仍然难以捉摸。我们旨在通过寻找癌症干细胞参与的证据以及ZEB1在癌细胞可塑性中的潜在作用，来阐明葡萄膜黑色素瘤（UM）中的这种异质性。
解剖源自人UM细胞的球体以及裸鼠体内的异种移植肿瘤，以寻找异质性和可塑性的迹象。研究了两个人UM细胞系：上皮样C918细胞系和纺锤形OCM1细胞系。我们在这两个细胞系中敲低ZEB1，以通过qRT-PCR、免疫组织化学、流式细胞术、电泳迁移率变动分析（EMSA）和染色质免疫沉淀（ChIP）分析来研究其参与干细胞样细胞形成和血管生成的调控。
我们发现，OCM1中的一个小侧群（SP）在体外形成球体后表现出干细胞样特性，如异质性、远距离扩散和核染料排斥。ZEB1通过促进细胞增殖间接调节UM干细胞的生成，从而在体内形成大尺寸肿瘤，在体外形成球体，并通过与TERT和ABCB1等干性基因结合直接发挥作用。此外，我们发现ZEB1通过调节CD34和VE-钙黏蛋白的表达参与血管生成拟态系统的形成。
根据我们的数据，我们得出结论，癌症干细胞可能导致UM的异质性和可塑性，并且ZEB1可能在其中发挥调节作用。
