Cellular and Molecular Oncobiology Program, Cellular Dynamic and Structure Group, Brazilian National Cancer Institute (INCA), Rio de Janeiro, Brazil.
Cellular and Molecular Oncobiology Program, Cellular Dynamic and Structure Group, Brazilian National Cancer Institute (INCA), Rio de Janeiro, Brazil.
Biochim Biophys Acta Mol Cell Res. 2019 Mar;1866(3):418-429. doi: 10.1016/j.bbamcr.2018.10.003. Epub 2018 Oct 5.
Colorectal cancer (CRC) is frequently a lethal disease because of metastasis. Actin cytoskeletal rearrangement is an essential step in cell migration during activation of the epithelial-mesenchymal transition (EMT) program, which is associated with metastatic properties of cancer cells. Cofilin-1 protein modulates actin dynamics by promoting actin treadmilling, thereby driving membrane protrusion and cell migration and invasion. However, the role of cofilin-1 during EMT in CRC is unknown. Here, we show that cofilin-1 and p-cofilin-1 have distinct subcellular distribution in EMT cells, as determined by super-resolution microscopy images, indicating distinct roles in different areas of cells. Silenced cofilin-1 cells treated with TGF-β (siCofilin-1/TGF-β) evaded p-LIMK2-p-cofilin-1 status, leading to recovery of E-cadherin and claudin-3 at the cell-cell contact and their respective protein levels, actin reorganization, and decreased mesenchymal protein level. Furthermore, siCofilin-1/TGF-β cells exhibited decreased migration and invasion rates as well as MMP-2 and -9 activity and augmented focal adhesion size. The expression of an inactive phospho-cofilin-1 mimetic (S3E) reduced E-cadherin and claudin-3 in cell-cell contacts, reduced their protein levels, and increased vimentin protein. Based on our findings, we suggest that cofilin-1 is crucial to switching from epithelial to mesenchymal-like morphology and cell migration and invasion by regulating actin cytoskeleton organization through activation of RhoA-LIMK2-cofilin-1 signaling, impacting the cell-cell adhesion organization of colon cancer cells in EMT.
结直肠癌（CRC）常因转移而导致致命。肌动蛋白细胞骨架重排是上皮-间质转化（EMT）程序激活过程中细胞迁移的一个关键步骤，与癌细胞的转移特性相关。丝切蛋白-1 蛋白通过促进肌动蛋白的踩踏来调节肌动蛋白动力学，从而驱动细胞膜的突出和细胞的迁移和侵袭。然而，丝切蛋白-1 在 CRC 中的 EMT 中的作用尚不清楚。在这里，我们通过超分辨率显微镜图像显示，丝切蛋白-1 和磷酸化丝切蛋白-1 在 EMT 细胞中有不同的亚细胞分布，表明其在细胞不同区域发挥不同的作用。用 TGF-β 处理的沉默丝切蛋白-1 细胞（siCofilin-1/TGF-β）逃避了 p-LIMK2-磷酸化丝切蛋白-1 的状态，导致细胞间接触处的 E-钙黏蛋白和闭合蛋白-3及其各自的蛋白水平、肌动蛋白重排以及间质蛋白水平的恢复。此外，siCofilin-1/TGF-β 细胞的迁移和侵袭率以及 MMP-2 和 MMP-9 的活性和粘着斑的大小降低。无活性磷酸化丝切蛋白-1 模拟物（S3E）的表达减少了细胞间接触处的 E-钙黏蛋白和闭合蛋白-3，降低了它们的蛋白水平，并增加了波形蛋白的蛋白水平。基于我们的发现，我们认为丝切蛋白-1 通过激活 RhoA-LIMK2-丝切蛋白-1 信号通路调节肌动蛋白细胞骨架的组织，对 EMT 中结肠癌细胞的细胞间黏附组织至关重要，从而对结直肠癌细胞的上皮样形态和细胞迁移以及侵袭起开关作用。
