Qin Cheng, Li Tianhao, Wang Yuanyang, Zhao Bangbo, Li Zeru, Li Tianyu, Yang Xiaoying, Zhao Yutong, Wang Weibin
Department of General Surgery, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
Division of Plastic Surgery, Department of Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
Cancer Cell Int. 2022 Nov 7;22(1):340. doi: 10.1186/s12935-022-02768-8.
Pancreatic cancer is one of the most lethal disease with highly fatal and aggressive properties. Lymph node ratio (LNR), the ratio of the number of metastatic lymph nodes to the total number of examined lymph nodes, is an important index to assess lymphatic metastasis and predict prognosis, but the molecular mechanism underlying high LNR was unclear.
Gene expression and clinical information data of pancreatic cancer were obtained from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO). Patients in TCGA were averagely divided into low and high LNR groups. Then, Weighted Gene Co-expression Network Analysis (WGCNA) was utilized to build co-expression network to explore LNR-related modules and hub genes. GO and KEGG analysis was performed to find key pathways related to lymph node metastasis. Next, GSE101448 and the overall survival data in TCGA was employed to further select significant genes from hub genes. Considering the key role of CHRNB2 in LNR and survival, gene set enrichment analysis (GSEA) was applied to find pathways related to CHRNB2 expression in pancreatic cancer. The contribution of CHRNB2 to migrative and invasive ability of pancreatic cancer cells was confirmed by Transwell assays. We finally explored the role of CHRNB2 in EMT and β-catenin pathway via Western Blot.
High LNR was significantly related to high T stages and poor prognosis. In WGCNA, 14 hub genes (COL5A1, FN1, THBS2, etc.) were positively related to high LNR, 104 hub genes (FFAR1, SCG5, TMEM63C, etc.) were negatively related to high LNR. After taking the intersection with GSE101448, 13 genes (CDK5R2, SYT7, CACNA2D2, etc.) which might prevent lymph node metastasis were further selected. Among them, CHRNB2 showed the strongest relationship with long survival. Moreover, CHRNB2 also negatively related to the T stages and LNR. Next, knockdown of CHRNB2 expression could acetylcholine (ACh)-independently increase the migration and invasion of pancreatic cancer cells, while CHRNB2 overexpression ACh-independently decrease the migration and invasion of pancreatic cancer cells. For exploring the underlying mechanism, CHRNB2 downregulated β-catenin pathway might through controlling its upstream regulators such as SOX6, SRY, SOX17, and TCF7L2.
CHRNB2 negatively relates to lymph node metastasis in pancreatic cancer patients. CHRNB2 could inhibit β-catenin pathway, EMT, migration and invasion of pancreatic cancer cells via ACh-independent mechanism.
胰腺癌是最致命的疾病之一，具有高度致命性和侵袭性。淋巴结比率（LNR），即转移淋巴结数量与检查的淋巴结总数之比，是评估淋巴转移和预测预后的重要指标，但高LNR背后的分子机制尚不清楚。
从癌症基因组图谱（TCGA）和基因表达综合数据库（GEO）获取胰腺癌的基因表达和临床信息数据。将TCGA中的患者平均分为低LNR组和高LNR组。然后，利用加权基因共表达网络分析（WGCNA）构建共表达网络，以探索与LNR相关的模块和枢纽基因。进行基因本体论（GO）和京都基因与基因组百科全书（KEGG）分析，以找出与淋巴结转移相关的关键途径。接下来，使用GSE101448和TCGA中的总生存数据，从枢纽基因中进一步筛选出显著基因。考虑到CHRNB2在LNR和生存中的关键作用，应用基因集富集分析（GSEA）来找出胰腺癌中与CHRNB2表达相关的途径。通过Transwell实验证实CHRNB2对胰腺癌细胞迁移和侵袭能力的影响。我们最终通过蛋白质免疫印迹法探讨CHRNB2在上皮-间质转化（EMT）和β-连环蛋白途径中的作用。
高LNR与高T分期及预后不良显著相关。在WGCNA中，14个枢纽基因（COL5A1、FN1、THBS2等）与高LNR呈正相关，104个枢纽基因（FFAR1、SCG5、TMEM63C等）与高LNR呈负相关。与GSE101448取交集后，进一步筛选出13个可能预防淋巴结转移的基因（CDK5R2、SYT7、CACNA2D2等）。其中，CHRNB2与长期生存的关系最为密切。此外，CHRNB2也与T分期和LNR呈负相关。接下来，敲低CHRNB2表达可在不依赖乙酰胆碱（ACh）的情况下增加胰腺癌细胞的迁移和侵袭，而CHRNB2过表达则在不依赖ACh的情况下降低胰腺癌细胞的迁移和侵袭。为探究潜在机制，CHRNB2下调β-连环蛋白途径可能是通过控制其上游调节因子，如SOX6、SRY、SOX17和TCF7L2。
CHRNB2与胰腺癌患者的淋巴结转移呈负相关。CHRNB2可通过不依赖ACh的机制抑制β-连环蛋白途径、EMT以及胰腺癌细胞的迁移和侵袭。
