Novartis Institutes for Biomedical Research, Cambridge, Massachusetts 02139.
Novartis Institutes for Biomedical Research, Horsham, West Sussex, RH12 5AB, United Kingdom, and.
J Biol Chem. 2014 Apr 18;289(16):11029-11041. doi: 10.1074/jbc.M114.549188. Epub 2014 Mar 5.
ANO1, a calcium-activated chloride channel, is highly expressed and amplified in human cancers and is a critical survival factor in these cancers. The ANO1 inhibitor CaCCinh-A01 decreases proliferation of ANO1-amplified cell lines; however, the mechanism of action remains elusive. We explored the mechanism behind the inhibitory effect of CaCCinh-A01 on cell proliferation using a combined experimental and in silico approach. We show that inhibition of ANO1 function is not sufficient to diminish proliferation of ANO1-dependent cancer cells. We report that CaCCinh-A01 reduces ANO1 protein levels by facilitating endoplasmic reticulum-associated, proteasomal turnover of ANO1. Washout of CaCCinh-A01 rescued ANO1 protein levels and resumed cell proliferation. Proliferation of newly derived CaCCinh-A01-resistant cell pools was not affected by CaCCinh-A01 as compared with the parental cells. Consistently, CaCCinh-A01 failed to reduce ANO1 protein levels in these cells, whereas ANO1 currents were still inhibited by CaCCinh-A01, indicating that CaCCinh-A01 inhibits cell proliferation by reducing ANO1 protein levels. Furthermore, we employed in silico methods to elucidate novel biological functions of ANO1 inhibitors. Specifically, we derived a pharmacophore model to describe inhibitors capable of promoting ANO1 degradation and report new inhibitors of ANO1-dependent cell proliferation. In summary, our data demonstrate that inhibition of the channel activity of ANO1 is not sufficient to inhibit ANO1-dependent cell proliferation, indicating that the role of ANO1 in cancer only partially depends on its function as a channel. Our results provide an impetus for gaining a deeper understanding of ANO1 modulation in cells and introduce a new targeting approach for antitumor therapy in ANO1-amplified cancers.
ANO1 是一种钙激活氯离子通道,在人类癌症中高度表达和扩增,是这些癌症中关键的生存因素。ANO1 抑制剂 CaCCinh-A01 可降低 ANO1 扩增细胞系的增殖;然而,其作用机制仍不清楚。我们采用实验和计算相结合的方法探索 CaCCinh-A01 对细胞增殖抑制作用的机制。结果表明,抑制 ANO1 功能不足以减少依赖 ANO1 的癌细胞的增殖。我们报告 CaCCinh-A01 通过促进内质网相关的蛋白酶体降解来降低 ANO1 蛋白水平。CaCCinh-A01 洗脱后可恢复 ANO1 蛋白水平并恢复细胞增殖。与亲本细胞相比,新衍生的 CaCCinh-A01 耐药细胞池的增殖不受 CaCCinh-A01 的影响。同样,CaCCinh-A01 未能降低这些细胞中的 ANO1 蛋白水平,而 ANO1 电流仍被 CaCCinh-A01 抑制,表明 CaCCinh-A01 通过降低 ANO1 蛋白水平抑制细胞增殖。此外,我们采用计算方法阐明了 ANO1 抑制剂的新生物学功能。具体而言,我们推导了一个药效团模型来描述能够促进 ANO1 降解的抑制剂,并报告了新的依赖 ANO1 细胞增殖的抑制剂。总之,我们的数据表明,抑制 ANO1 通道活性不足以抑制依赖 ANO1 的细胞增殖,这表明 ANO1 在癌症中的作用部分取决于其作为通道的功能。我们的结果为深入了解 ANO1 在细胞中的调节作用提供了动力,并为针对 ANO1 扩增癌症的抗肿瘤治疗引入了新的靶向方法。