Role of Filamin A in Inflammation and Oncogenesis

使用了许多具有不同转移潜能的人黑色素瘤细胞系，并证明细丝蛋白A和EGF受体的表达与转移呈正相关。EGF受体激酶的药理学抑制和RNA干扰介导的细丝蛋白A基因的沉默被用于显示EGF介导的黑素瘤细胞迁移的显著减少，如通过伤口愈合测定所测量的。进行了额外的实验，并确定细丝蛋白A是有效的EGF受体活化所需的，与接头分子的关联和内吞受体进入降解途径的分选。细丝蛋白A与EGF受体激活和功能相关的早期事件之间存在联系，可能在癌症中具有潜在的治疗应用。 早期的研究表明，细丝蛋白A也可以与ROR2相互作用，ROR2是一种孤儿酪氨酸激酶受体，其与Wnt 5A的结合导致黑色素瘤细胞运动。进行了使用siRNA敲低WNT 5A基因的研究，并证明细丝蛋白A表达显著降低，同时黑色素瘤细胞运动性降低。进行了额外的实验，并显示Wnt 5A促进迁移的能力归因于钙蛋白酶1介导的细丝蛋白A切割的增加。发现细胞内钙的螯合和钙蛋白酶1的药理学或siRNA介导的抑制可阻断细丝蛋白A裂解和细胞运动。 这些数据表明，靶向钙蛋白酶介导的细丝蛋白A的切割可能对肿瘤细胞的运动性和侵袭性具有重要意义。肌动蛋白细胞骨架重塑，从切割细丝蛋白A的结果可能是一个重要的集成商的许多信号级联，参与核受体的核质穿梭和调节其转录活性。

A number of human melanoma cell lines with varying metastatic potential were used and demonstrated a positive correlation between the expression of filamin A and EGF receptor with metastasis. Pharmacological inhibition of the EGF receptor kinase and RNA interference-mediated silencing of filamin A gene were used to show marked reduction in EGF-mediated melanoma cell migration as measured by wound-healing assays. Additional experiments were carried out and established that filamin A was required for efficient EGF receptor activation, association with adaptor molecules and sorting of endocytosed receptors into the degradation pathway. The existence of a link between filamin A and the early events associated with EGF receptor activation and function could have potential therapeutic applications in cancer. Earlier studies have shown that filamin A can also interact with ROR2, an orphan tyrosine kinase receptor, whose binding with Wnt5A results in melanoma cell motility. A study using siRNA knockdown of WNT5A gene was conducted and demonstrated that filamin A expression was significantly reduced with concomitant decrease in melanoma cell motility. Additional experiments were performed and showed that the ability of Wnt5A to promote migration was ascribed to an increase in calpain 1-mediated cleavage of filamin A. Chelation of intracellular calcium and pharmacological or siRNA-mediated inhibition of calpain 1 were found to block filamin A cleavage and cell motility. These data indicate that targeting calpain-mediated cleavage of filamin A could have significant implications for tumor cell motility and invasiveness. Actin cytoskeleton remodeling that results from cleavage of filamin A may be an important integrator for the many signaling cascades that are involved in nucleocytoplasmic shuttling of nuclear receptors and regulation of their transcriptional activities.