Department of Pathology, Sahlgrenska Cancer Center, Gothenburg University, Gothenburg, Sweden.
Wellcome Trust Centre for Cell Matrix Research, Faculty of Life Sciences, University of Manchester, Michael Smith Building, Manchester, UK.
Oncogene. 2015 Jan 2;34(1):27-38. doi: 10.1038/onc.2013.527. Epub 2013 Dec 16.
Transforming growth factor-beta (TGF-β) is a pleiotropic cytokine with the capability to act as tumour suppressor or tumour promoter depending on the cellular context. TGF-beta receptor type-2 (TGFBR2) is the ligand-binding receptor for all members of the TGF-β family. Data from mouse model experiments demonstrated that loss of Tgfbr2 expression in mammary fibroblasts was linked to tumour initiation and metastasis. Using a randomised tamoxifen trial cohort including in total 564 invasive breast carcinomas, we examined TGFBR2 expression (n=252) and phosphorylation level of downstream target SMAD2 (pSMAD2) (n=319) in cancer-associated fibroblasts (CAFs) and assessed links to clinicopathological markers, prognostic and treatment-predictive values. The study revealed that CAF-specific TGFBR2 expression correlated with improved recurrence-free survival. Multivariate analysis confirmed CAF-TGFBR2 to be an independent prognostic marker (multivariate Cox regression, hazard ratio: 0.534, 95% (CI): 0.360-0.793, P=0.002). CAF-specific pSMAD2 levels, however, did not associate with survival outcome. Experimentally, TGF-β signalling in fibroblasts was modulated using a TGF-β ligand and inhibitor or through lentiviral short hairpin RNA-mediated TGFBR2-specific knockdown. To determine the role of fibroblastic TGF-β pathway on breast cancer cells, we used cell contact-dependent cell growth and clonogenicity assays, which showed that knockdown of TGFBR2 in CAFs resulted in increased cell growth, proliferation and clonogenic survival. Further, in a mouse model transfected CAFs were co-injected with MCF7 and tumour weight and proportion was monitored. We found that mouse xenograft tumours comprising TGFBR2 knockdown fibroblasts were slightly bigger and displayed increased tumour cell capacity. Overall, our data demonstrate that fibroblast-related biomarkers possess clinically relevant information and that fibroblasts confer effects on breast cancer cell growth and survival. Regulation of tumour-stromal cross-talk through fibroblastic TGF-β pathway may depend on fibroblast phenotype, emphasising the importance to characterise tumour microenvironment subtypes.
转化生长因子-β（TGF-β）是一种多功能细胞因子，根据细胞环境的不同，它可以作为肿瘤抑制因子或肿瘤促进因子发挥作用。TGF-β 受体 2 型（TGFBR2）是 TGF-β 家族所有成员的配体结合受体。来自小鼠模型实验的数据表明，乳腺成纤维细胞中 Tgfbr2 表达的缺失与肿瘤起始和转移有关。使用包括总共 564 例浸润性乳腺癌的随机他莫昔芬试验队列，我们检查了癌症相关成纤维细胞（CAF）中 TGFBR2 表达（n=252）和下游靶标 SMAD2 的磷酸化水平（pSMAD2）（n=319），并评估了与临床病理标志物、预后和治疗预测价值的关联。研究表明，CAF 特异性 TGFBR2 表达与无复发生存率的改善相关。多变量分析证实 CAF-TGFBR2 是一个独立的预后标志物（多变量 Cox 回归，风险比：0.534，95%置信区间：0.360-0.793，P=0.002）。然而，CAF 特异性 pSMAD2 水平与生存结果无关。实验中，使用 TGF-β 配体和抑制剂或通过慢病毒短发夹 RNA 介导的 TGFBR2 特异性敲低来调节成纤维细胞中的 TGF-β 信号。为了确定成纤维细胞 TGF-β 途径对乳腺癌细胞的作用，我们使用了细胞接触依赖性细胞生长和集落形成测定，结果表明 CAF 中 TGFBR2 的敲低导致细胞生长、增殖和集落形成存活增加。此外，在转染 CAFs 的小鼠模型中，MCF7 被共同注射，监测肿瘤重量和比例。我们发现，含有 TGFBR2 敲低成纤维细胞的小鼠异种移植瘤稍大，显示出增加的肿瘤细胞能力。总的来说，我们的数据表明，成纤维细胞相关生物标志物具有临床相关信息，成纤维细胞赋予乳腺癌细胞生长和存活的效应。通过成纤维细胞 TGF-β 途径调节肿瘤-基质相互作用可能取决于成纤维细胞表型，强调了对肿瘤微环境亚型进行特征描述的重要性。
