Abstract：
Cancer-associated fibroblasts (CAFs) interact reciprocally with tumor cells through various signaling pathways in many cancer types including cutaneous squamous cell carcinoma (cSCC). Among normal fibroblast (NF) subtypes, papillary fibroblasts (PFs) and reticular fibroblasts (RFs) respond distinctly to tumor cell signaling, eventuating the differentiation of RFs, rather than PFs, into CAFs. The regulation of subtype differentiation in fibroblasts remains poorly explored. In this study, we assessed the differences between PFs, RFs, and CAFs, and examined the effects of small-molecule inhibitors targeting the TGFβ, PI3K/AKT/mTOR, and NOTCH pathways on the tumor-promoting property of CAFs and CAF reprogramming in 2D and 3D cultures. Blocking TGFβ and PI3K strongly deactivated and concurrently induced a PF phenotype in RFs and CAFs. 3D co-culturing a cSCC cell line MET2 with RFs or CAFs led to enhanced tumor invasion, \"RF-CAF\" transition and cytokine production, which were further repressed by blocking TGFβ and PI3K/mTOR pathways, but not NOTCH pathway. In conclusion, the study identified biomarkers for PFs, RFs and CAFs, and displayed different effects of blocking key signaling pathways in CAFs and tumor cell-CAF interplay. These findings prompted a \"CAF to PF\" therapeutic strategy, and provided perspectives of using included inhibitors in CAF-based cancer therapy.
摘要：
在包括皮肤鳞状细胞癌(cSCC)的许多癌症类型中,癌相关成纤维细胞(CAF)通过各种信号传导途径与肿瘤细胞相互作用。在正常成纤维细胞（NF）亚型中，乳头状成纤维细胞（PFs）和网状成纤维细胞（RFs）对肿瘤细胞信号传导有明显的反应，最终实现了RF的差异化，而不是PF，进入CAF。成纤维细胞中亚型分化的调节仍未得到充分探索。在这项研究中,我们评估了PF之间的差异，RFs,和CAF，并检查了靶向TGFβ的小分子抑制剂的作用，PI3K/AKT/mTOR,和NOTCH通路对2D和3D培养中CAF和CAF重编程的肿瘤促进特性的影响。阻断TGFβ和PI3K强烈失活并同时诱导RF和CAF中的PF表型。3D共培养cSCC细胞系MET2与RF或CAF导致增强的肿瘤侵袭，“RF-CAF”转换和细胞因子产生，通过阻断TGFβ和PI3K/mTOR途径进一步抑制，但不是NOTCH途径。总之,这项研究确定了PFs的生物标志物，RF和CAF,并显示出阻断CAF和肿瘤细胞-CAF相互作用中关键信号通路的不同作用。这些发现促使了“CAF到PF”的治疗策略，并提供了在基于CAF的癌症治疗中使用包含的抑制剂的观点。
