Three-dimensional (3D) multicellular tumor spheroid (MCTS) cultures are increasingly popular as an in vitro tumor model for drug screening because they can mimic the complexity and heterogeneity of tumors compared to 2D monolayer cell cultures. The oncogenic microRNA, miR-21-5p (hereafter denoted as miR-21), is one of the most upregulated miRNAs in colorectal cancer (CRC). Herein, we established a stable miR-21-overexpressing clone in the DLD-1 human CRC cell line to investigate its impact on MCTS formation. We found that miR-21 overexpression enhanced cell-cell interactions/aggregations in both 2D monolayer and 3D suspension cultures. Cell aggregates in 3D suspension culture further formed MCTSs in miR-21-overexpressing cells. miR-21 overexpression was associated with the upregulation of proteins involved in E-cadherin-associated cell-cell adhesion. Furthermore, miR-21 induction of MCTSs could be reversed by the antibody-induced blockade of E-cadherin. Our results showed that miR-21 overexpression promoted MCTS formation through enhancing E-cadherin-dependent cell-cell interactions, which represents an advance in vitro model for investigating CRC biology.

中文翻译：

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miR-21-5p在大肠癌细胞中的过表达促进E-钙粘着蛋白依赖性多细胞肿瘤球体的自组装。

三维（3D）多细胞肿瘤球体（MCTS）培养作为药物筛选的体外肿瘤模型越来越受欢迎，因为与2D单层细胞培养相比，它们可以模拟肿瘤的复杂性和异质性。致癌微RNA miR-21-5p（以下称为miR-21）是结直肠癌（CRC）中表达最上调的miRNA之一。在本文中，我们在DLD-1人CRC细胞系中建立了稳定的miR-21过表达克隆，以研究其对MCTS形成的影响。我们发现miR-21的过表达增强了2D单层和3D悬浮培养物中的细胞间相互作用/聚集。3D悬浮培养中的细胞聚集体进一步在miR-21过表达的细胞中形成了MCTS。miR-21的过表达与参与E-钙黏着蛋白相关的细胞粘附的蛋白质上调有关。此外，MCRs的miR-21诱导可通过抗体诱导的E-钙粘着蛋白阻断而逆转。我们的结果表明，miR-21过表达通过增强E-钙粘着蛋白依赖性细胞-细胞相互作用促进了MCTS的形成，这代表了研究CRC生物学的先进体外模型。