Cancer Science Institute of Singapore (M.G., D.K., S.J., V.M., W.C., A.S., LW.D., M.X., L.-Z.L., H.Y., H.P.K.), National University of Singapore, and National University Cancer Institute (H.P.K.), National University Hospital, 117599 Singapore; Division of Hematology/Oncology (R.O., S.G., H.P.K.), Cedars-Sinai Medical Center, and Departments of Pathology and Laboratory Medicine (J.W.S., N.B.D.), Medicine (G.D.B), David Geffen School of Medicine, University of California School of Medicine, Los Angeles, California 90059.
J Clin Endocrinol Metab. 2014 Jan;99(1):E62-72. doi: 10.1210/jc.2013-2994. Epub 2013 Dec 20.
Anaplastic thyroid carcinoma (ATC) is an aggressive malignancy having no effective treatment. Laminin subunit-γ-2 (LAMC2) is an epithelial basement membrane protein involved in cell migration and tumor invasion and might represent an ideal target for the development of novel therapeutic approaches for ATC.
The objective of the investigation was to study the role of LAMC2 in ATC tumorigenesis.
LAMC2 expression was evaluated by RT-PCR, Western blotting, and immunohistochemistry in tumor specimens, adjacent noncancerous tissues, and cell lines. The short hairpin RNA (shRNA) approach was used to investigate the effect of LAMC2 knockdown on the tumorigenesis of ATC.
LAMC2 was highly expressed in ATC samples and cell lines compared with normal thyroid tissues. Silencing LAMC2 by shRNA in ATC cells moderately inhibited cell growth in liquid culture and dramatically decreased growth in soft agar and in xenografts growing in immunodeficient mice. Silencing LAMC2 caused cell cycle arrest and significantly suppressed the migration, invasion, and wound healing of ATC cells. Rescue experiments by overexpressing LAMC2 in LAMC2 knockdown cells reversed the inhibitory effects as shown by increased cell proliferation and colony formation. Microarray data demonstrated that LAMC2 shRNA significantly altered the expression of genes associated with migration, invasion, proliferation, and survival. Immunoprecipitation studies showed that LAMC2 bound to epidermal growth factor receptor (EGFR) in the ATC cells. Silencing LAMC2 partially blocked epidermal growth factor-mediated activation of EGFR and its downstream pathway. Interestingly, cetuximab (an EGFR blocking antibody) or EGFR small interfering RNA additively enhanced the antiproliferative activity of the LAMC2 knockdown ATC cells compared with the control cells.
To our knowledge, this is the first report investigating the effect of LAMC2 on cell growth, cell cycle, migration, invasion, and EGFR signaling in ATC cells, suggesting that LAMC2 may be a potential therapeutic target for the treatment of ATC.
间变性甲状腺癌（ATC）是一种侵袭性恶性肿瘤，目前尚无有效的治疗方法。层粘连蛋白亚单位-γ-2（LAMC2）是一种参与细胞迁移和肿瘤侵袭的上皮基底膜蛋白，可能是开发用于 ATC 的新型治疗方法的理想靶点。
本研究旨在探讨 LAMC2 在 ATC 肿瘤发生中的作用。
通过 RT-PCR、Western blot 和免疫组织化学检测肿瘤标本、相邻非癌组织和细胞系中 LAMC2 的表达。采用短发夹 RNA（shRNA）方法研究 LAMC2 敲低对 ATC 肿瘤发生的影响。
与正常甲状腺组织相比，LAMC2 在 ATC 样本和细胞系中高表达。在 ATC 细胞中用 shRNA 沉默 LAMC2 可适度抑制液体培养中的细胞生长，并显著降低软琼脂中的生长和免疫缺陷小鼠中的异种移植物生长。沉默 LAMC2 导致细胞周期停滞，并显著抑制 ATC 细胞的迁移、侵袭和伤口愈合。通过在 LAMC2 敲低细胞中转染 LAMC2 过表达来进行挽救实验，结果显示细胞增殖和集落形成增加，从而逆转了抑制作用。微阵列数据分析表明，LAMC2 shRNA 显著改变了与迁移、侵袭、增殖和存活相关的基因表达。免疫沉淀研究表明，LAMC2 在 ATC 细胞中与表皮生长因子受体（EGFR）结合。沉默 LAMC2 部分阻断了表皮生长因子介导的 EGFR 及其下游途径的激活。有趣的是，西妥昔单抗（一种 EGFR 阻断抗体）或 EGFR 小干扰 RNA 与对照细胞相比，可附加增强 LAMC2 敲低 ATC 细胞的抗增殖活性。
据我们所知，这是第一项研究 LAMC2 对 ATC 细胞生长、细胞周期、迁移、侵袭和 EGFR 信号的影响的报告，表明 LAMC2 可能是治疗 ATC 的潜在治疗靶点。
