Division of Molecular and Gene Therapies, Griffith Institute for Health and Medical Research, School of Medical Science, Griffith University, Gold Coast campus, Southport, Qld 4222, Australia.
Mol Cancer. 2009 Sep 27;8:78. doi: 10.1186/1476-4598-8-78.
Tumour stromal myofibroblasts can promote tumour invasion. As these cells are genetically more stable than cancer cells, there has been enormous interest in developing targeted molecular therapies against them. Chloride intracellular channel 4 (CLIC4) and reactive oxygen species (ROS) have been linked with promoting stromal cell transdifferentiation in various cancers, but little is known of their roles in ovarian cancer. In this study, we examined the functional roles that both CLIC4 and ROS play in the process of ovarian cancer cell-stimulated or TGF-beta1 induced fibroblast-to-myofibroblast transdifferentiation. We also examine whether it is possible to reverse such a process, with the aim of developing novel therapies against ovarian cancer by targeting activated transdifferentiated myofibroblasts.
We demonstrate that TGF-beta1 induced or CM(SKOV3) activate transdifferentiated myofibroblasts (fibroblasts). These fibroblasts mimic "reactive" stromal myofibroblasts and demonstrate significant up-regulation of CLIC4 expression and increased level of ROS production. Blocking the production of ROS with an antioxidant consequently reduces the expression of CLIC4, and is accompanied by disappearance of alpha-smooth-muscle actin (alpha-SMA), a myofibroblast marker, suggesting ROS acts as a signalling molecule that promotes and enhances CLIC4 activities in the myofibroblast transdifferentiaton process. Down-regulation of CLIC4 with a generic agent or specific siRNA both significantly reduces the expression of factors related to the phenotypes and functions of myofibroblasts, such as alpha-SMA, hepatocyte growth factor (HGF) and vascular endothelial growth factor (VEGF), thus reversing the myofibroblast phenotype back to fibroblasts. These results convincingly show that ROS and CLIC4 are responsible for TGF-beta1 induced fibroblast-to-myofibroblast transdifferentiaton and down-regulation of both is sufficient to block transdifferentiated myofibroblasts.
Molecular targeting of ROS and CLIC4 has the potential to develop novel therapies for ovarian cancer.
肿瘤间质肌纤维母细胞可以促进肿瘤侵袭。由于这些细胞的遗传稳定性比癌细胞更高，因此人们对针对它们的靶向分子治疗产生了浓厚的兴趣。氯离子细胞内通道 4（CLIC4）和活性氧（ROS）与促进各种癌症中基质细胞转分化有关，但对其在卵巢癌中的作用知之甚少。在这项研究中，我们研究了 CLIC4 和 ROS 在卵巢癌细胞刺激或 TGF-β1 诱导的成纤维细胞向肌纤维母细胞转分化过程中的功能作用。我们还研究了是否有可能逆转这种过程，旨在通过靶向激活的转分化肌纤维母细胞来开发针对卵巢癌的新疗法。
我们证明 TGF-β1 诱导或 CM（SKOV3）激活了转分化的肌纤维母细胞（成纤维细胞）。这些成纤维细胞模拟“反应性”基质肌纤维母细胞，并表现出 CLIC4 表达的显著上调和 ROS 产生水平的增加。用抗氧化剂阻断 ROS 的产生会降低 CLIC4 的表达，并伴随着α-平滑肌肌动蛋白（α-SMA）的消失，这是肌纤维母细胞的标志物，表明 ROS 作为一种信号分子，促进和增强了 CLIC4 在肌纤维母细胞转分化过程中的活性。用通用试剂或特异性 siRNA 下调 CLIC4 都显著降低了与肌纤维母细胞表型和功能相关的因子的表达，如α-SMA、肝细胞生长因子（HGF）和血管内皮生长因子（VEGF），从而使肌纤维母细胞表型逆转回成纤维细胞。这些结果令人信服地表明，ROS 和 CLIC4 负责 TGF-β1 诱导的成纤维细胞向肌纤维母细胞转分化，下调两者足以阻断转分化的肌纤维母细胞。
ROS 和 CLIC4 的分子靶向具有开发针对卵巢癌的新疗法的潜力。
