Sasaki Norihiko, Shinji Seiichi, Shichi Yuuki, Ishiwata Toshiyuki, Arai Tomio, Yamada Takeshi, Takahashi Goro, Ohta Ryo, Sonoda Hiromichi, Matsuda Akihisa, Iwai Takuma, Takeda Kohki, Yonaga Kazuhide, Ueda Koji, Kuriyama Sho, Miyasaka Toshimitsu, Yoshida Hiroshi
Research Team for Geriatric Medicine (Vascular Medicine), Tokyo Metropolitan Institute of Gerontology, Tokyo, 173-0015, Japan.
Department of Gastrointestinal and Hepato-Biliary-Pancreatic Surgery, Nippon Medical School, Tokyo, 113-8603, Japan.
Biochem Biophys Rep. 2022 Mar 1;30:101239. doi: 10.1016/j.bbrep.2022.101239. eCollection 2022 Jul.
Epithelial-mesenchymal transition (EMT) plays a pivotal role in cancer progression and metastasis in many types of malignancies, including colorectal cancer. Although the importance of EMT is also considered in colorectal neuroendocrine carcinoma (NEC), its regulatory mechanisms have not been elucidated. We recently established a human colorectal NEC cell line, SS-2. In this study, we aimed to clarify whether these cells were sensitive to transforming growth factor beta 1 (TGF-β1) and whether EMT could be induced through TGF-β1/Smad signaling, with the corresponding NEC cell-specific changes in invasiveness. In SS-2 cells, activation of TGF-β1 signaling, as indicated by phosphorylation of Smad2/3, was dose-dependent, demonstrating that SS-2 cells were responsive to TGF-β1. Analysis of EMT markers showed that mRNA levels changed with TGF-β1 treatment and that E-cadherin, an EMT marker, was expressed in cell-cell junctions even after TGF-β1 treatment. Invasion assays showed that TGF-β1-treated SS-2 cells invaded more rapidly than non-treated cells, and these cells demonstrated increased metalloproteinase activity and cell adhesion. Among integrins involved in cell-to-matrix adhesion, α2-integrin was exclusively upregulated in TGF-β1-treated SS-2 cells, but not in other colon cancer cell lines, and adhesion and invasion were inhibited by an anti-α2-integrin blocking antibody. Our findings suggest that α2-integrin may represent a novel therapeutic target for the metastasis of colorectal NEC cells.
上皮-间质转化（EMT）在包括结直肠癌在内的多种恶性肿瘤的癌症进展和转移中起着关键作用。尽管在结直肠神经内分泌癌（NEC）中也考虑到了EMT的重要性，但其调控机制尚未阐明。我们最近建立了一种人结直肠NEC细胞系SS-2。在本研究中，我们旨在阐明这些细胞是否对转化生长因子β1（TGF-β1）敏感，以及EMT是否可通过TGF-β1/Smad信号通路诱导，并伴有相应的NEC细胞特异性侵袭性变化。在SS-2细胞中，如Smad2/3磷酸化所示，TGF-β1信号的激活呈剂量依赖性，表明SS-2细胞对TGF-β1有反应。对EMT标志物的分析表明，mRNA水平随TGF-β1处理而变化，并且即使在TGF-β1处理后，作为EMT标志物的E-钙黏蛋白仍在细胞间连接处表达。侵袭试验表明，经TGF-β1处理的SS-2细胞比未处理的细胞侵袭更快，并且这些细胞表现出金属蛋白酶活性增加和细胞黏附增强。在参与细胞与基质黏附的整合素中，α2整合素仅在经TGF-β1处理的SS-2细胞中上调，而在其他结肠癌细胞系中未上调，并且抗α2整合素阻断抗体可抑制黏附和侵袭。我们的研究结果表明，α2整合素可能是结直肠NEC细胞转移的一个新的治疗靶点。
