Tumor cells induce the cancer associated fibroblast phenotype via caveolin-1 degradation Implications for breast cancer and DCIS therapy with autophagy inhibitors
Tumor cells induce the cancer associated fibroblast phenotype via caveolin-1 degradation Implications for breast cancer and DCIS therapy with autophagy inhibitors
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DOI：
10.4161/cc.9.12.12048
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发表时间：
2010-06-15
期刊：
影响因子：
4.3
通讯作者：
Sotgia, Federica
中科院分区：
文献类型：
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作者：
Martinez-Outschoorn, Ubaldo E.;Pavlides, Stephanos;Sotgia, Federica
间质小窝蛋白1（Cav-1）的缺失是癌症相关成纤维细胞的一种新型生物标志物，可预测乳腺癌和DCIS患者的不良临床结局。我们假设上皮癌细胞可能有能力在邻近的正常成纤维细胞中驱动Cav-1下调，从而促进癌症相关的成纤维细胞表型。为了直接检验这一假设，我们开发了一种新的共培养模型，该模型采用（i）人乳腺癌细胞（MCF 7）和（ii）永生化的成纤维细胞（hTERT-BJ 1），它们在确定的实验条件下生长。重要的是，我们发现永生化的人成纤维细胞与MCF 7乳腺癌细胞的共培养导致成纤维细胞中Cav-1的下调。这些结果也用与MCF 7细胞共培养的正常人乳腺成纤维细胞的原代培养物来验证。在这个系统中，我们表明，Cav-1下调介导的自噬/溶酶体降解，作为预处理与溶酶体特异性抑制剂抢救Cav-1的表达。在功能上，我们证明了与MCF 7乳腺癌细胞共培养的成纤维细胞获得癌症相关的成纤维细胞表型，其特征在于Cav-1下调，肌成纤维细胞标志物和细胞外基质蛋白的表达增加，以及TGF β/Smad 2信号传导的组成性激活。siRNA介导的Cav-1下调模拟了共培养的成纤维细胞中发生的几个关键变化，清楚地表明Cav-1的缺失是一个关键的起始因子，在肿瘤发生期间驱动基质成纤维细胞活化。因此，这种共培养系统现在可以用作产生“合成的”癌症相关成纤维细胞（CAF）的实验模型。更具体地说，这些“合成”CAF可用于药物筛选，以鉴定选择性靶向Cav-1阴性肿瘤微环境的新型治疗剂。我们的发现还表明氯喹或其它自噬/溶酶体抑制剂可用作抗癌剂，以治疗性地恢复癌相关成纤维细胞中基质Cav-1的表达。我们讨论了这种可能性，根据一项使用氯喹治疗DCIS患者的新临床试验的启动：PINC（用氯喹预防浸润性乳腺肿瘤）[见http：//clinicaltrials.gov/show/NCT01023477]。clinicaltrials.gov/show/NCT01023477
Loss of stromal caveolin 1 (Cav-1) is a novel biomarker for cancer-associated fibroblasts that predicts poor clinical outcome in breast cancer and DCIS patients. We hypothesized that epithelial cancer cells may have the ability to drive Cav-1 downregulation in adjacent normal fibroblasts, thereby promoting the cancer associated fibroblast phenotype. to test this hypothesis directly, here we developed a novel co-culture model employing (i) human breast cancer cells (MCF7), and (ii) immortalized fibroblasts (hTERT-BJ1), which are grown under defined experimental conditions. Importantly, we show that co-culture of immortalized human fibroblasts with MCF7 breast cancer cells leads to Cav-1 downregulation in fibroblasts. these results were also validated using primary cultures of normal human mammary fibroblasts co-cultured with MCF7 cells. In this system, we show that Cav-1 downregulation is mediated by autophagic/lysosomal degradation, as pre-treatment with lysosome-specific inhibitors rescues Cav-1 expression. Functionally, we demonstrate that fibroblasts co-cultured with MCF7 breast cancer cells acquire a cancer associated fibroblast phenotype, characterized by Cav-1 downregulation, increased expression of myofibroblast markers and extracellular matrix proteins, and constitutive activation of TGF beta/Smad2 signaling. siRNA-mediated Cav-1 downregulation mimics several key changes that occur in co-cultured fibroblasts, clearly indicating that a loss of Cav-1 is a critical initiating factor, driving stromal fibroblast activation during tumorigenesis. As such, this co-culture system can now be used as an experimental model for generating "synthetic" cancer associated fibroblasts (CAFs). More specifically, these "synthetic" CAFs could be used for drug screening to identify novel therapeutics that selectively target the Cav-1-negative tumor micro-environment. our findings also suggest that chloroquine, or other autophagy/lysosome inhibitors, may be useful as anti-cancer agents, to therapeutically restore the expression of stromal Cav-1 in cancer associated fibroblasts. We discuss this possibility, in light of the launch of a new clinical trial that uses chloroquine to treat DCIS patients: PINC (preventing Invasive Breast Neoplasia with Cholorquine) [See http://clinicaltrials.gov/show/NCT01023477].//clinicaltrials.gov/show/NCT01023477