Institute of Toxicology, College of Preventive Medicine, Third Military Medical University (Army Medical University), 30 Gaotanyan Street, Shapingba District, Chongqing, 400038, People's Republic of China.
Laboratory of Cell Signal Transduction, Henan Provincial Engineering Centre for Tumor Molecular Medicine, Medical School of Henan University, Kaifeng, People's Republic of China.
J Cancer Res Clin Oncol. 2023 Feb;149(2):653-667. doi: 10.1007/s00432-022-04363-w. Epub 2022 Nov 10.
The TMEM196 protein, which comprises four membrane-spanning domains, belongs to the TMEM protein family. TMEM196 was identified as a candidate tumor suppressor gene in lung cancer. However, its role and mechanism in lung cancer metastasis remain unclear. Here, we study the role of TMEM196 in tumor metastasis to further verify the function in lung cancer.
In this study, we used qRT-PCR, western blot analysis and immunohistochemistry to examine the expression levels of TMEM196 and related proteins in lung cancer tissues and tumor cells. We utilized Transwell assays, xenograft nude mouse models, and TMEM196 mouse models to evaluate the effects of TMEM196 on tumor invasion and metastasis. Finally, we used bioinformatics analysis and dual-luciferase reporter gene assays to explore the molecular mechanism of TMEM196 as a tumor suppressor.
We found that TMEM196 mRNA and protein expression levels were significantly decreased in lung cancer tissues and cells. Low expression of TMEM196 in clinical patients was associated with poor prognosis. TMEM196 strongly inhibited tumor metastasis and progression in vitro and in vivo. The primary lung tumors induced by tail vein-inoculated B16 cells in TMEM196 mice were significantly larger than those in TMEM196 mice. Mechanistically, TMEM196 inhibited the Wnt signaling pathway and repressed β-catenin promoter transcription. TMEM196 silencing in lung cancer cells and mice resulted in significant upregulation of the expression of β-catenin and Wnt signaling pathway downstream target genes (MMP2 and MMP7). Decreasing β-catenin expression in TMEM196-silenced cancer cells attenuated the antimetastatic effect of TMEM196.
Our results revealed that TMEM196 acts as a novel lung cancer metastasis suppressor via the Wnt/β-catenin signaling pathway.
TMEM196 蛋白包含四个跨膜结构域，属于 TMEM 蛋白家族。TMEM196 被鉴定为肺癌的候选肿瘤抑制基因。然而，其在肺癌转移中的作用和机制尚不清楚。在这里，我们研究了 TMEM196 在肿瘤转移中的作用，以进一步验证其在肺癌中的功能。
在这项研究中，我们使用 qRT-PCR、western blot 分析和免疫组织化学方法检测了肺癌组织和肿瘤细胞中 TMEM196 及相关蛋白的表达水平。我们利用 Transwell 分析、异种移植裸鼠模型和 TMEM196 小鼠模型评估了 TMEM196 对肿瘤侵袭和转移的影响。最后，我们使用生物信息学分析和双荧光素酶报告基因检测来探讨 TMEM196 作为肿瘤抑制因子的分子机制。
我们发现 TMEM196 mRNA 和蛋白表达水平在肺癌组织和细胞中显著降低。临床患者中 TMEM196 的低表达与预后不良相关。TMEM196 在体外和体内强烈抑制肿瘤转移和进展。TMEM196 小鼠尾静脉接种 B16 细胞诱导的原发性肺肿瘤明显大于 TMEM196 小鼠。机制上，TMEM196 抑制 Wnt 信号通路并抑制 β-catenin 启动子转录。TMEM196 在肺癌细胞和小鼠中的沉默导致 β-catenin 和 Wnt 信号通路下游靶基因（MMP2 和 MMP7）的表达显著上调。在 TMEM196 沉默的癌细胞中降低 β-catenin 的表达减弱了 TMEM196 的抗转移作用。
我们的结果表明，TMEM196 通过 Wnt/β-catenin 信号通路作为一种新型肺癌转移抑制因子发挥作用。
