Small molecule-facilitated degradation of ANO1 protein: a new targeting approach for anticancer therapeutics.
Small molecule-facilitated degradation of ANO1 protein: a new targeting approach for anticancer therapeutics.
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DOI：
10.1074/jbc.m114.549188
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发表时间：
2014-04-18
期刊：
影响因子：
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通讯作者：
Gaither LA
中科院分区：
文献类型：
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作者：
Bill A;Hall ML;Borawski J;Hodgson C;Jenkins J;Piechon P;Popa O;Rothwell C;Tranter P;Tria S;Wagner T;Whitehead L;Gaither LA
背景：钙激活的氯离子通道ANO1在肿瘤中高表达。结果：单独抑制ANO1活性不足以抑制癌细胞增殖，提示ANO1蛋白在肿瘤中具有新的功能。结论：ANO1抑制剂CaCCinh-A01通过促进ANO1的降解而抑制癌细胞增殖。意义：我们的结果可能为ANO1扩增肿瘤的抗肿瘤治疗提供一种新的靶向治疗方法。ANO1是一种钙激活的氯离子通道，在人类癌症中高度表达和扩增，是这些癌症中的关键生存因素。ANO1抑制剂CaCCinh-A01可抑制ANO1扩增的细胞系的增殖，但其作用机制仍不清楚。我们用实验和电子显微镜相结合的方法探讨了CaCCinh-A01抑制细胞增殖的机制。我们发现，抑制ANO1功能不足以抑制依赖ANO1的癌细胞的增殖。我们报道，CaCCinh-A01通过促进内质网相关的蛋白酶体周转来降低ANO1的蛋白水平。CaCCinh-A01的缺失挽救了ANO1蛋白水平，并恢复了细胞增殖。与亲本细胞相比，CaCCinh-A01对新分化的CaCCinh-A01耐药细胞库的增殖无明显影响。CaCCinh-A01不能降低这些细胞的ANO1蛋白水平，而CaCCinh-A01仍然抑制ANO1电流，表明CaCCinh-A01通过降低ANO1蛋白水平来抑制细胞增殖。此外，我们还利用电子计算机方法阐明了ANO1抑制剂的新的生物学功能。具体地说，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ANO1依赖细胞增殖抑制剂。综上所述，我们的数据表明，抑制ANO1的通道活性不足以抑制ANO1依赖的细胞增殖，这表明ANO1在癌症中的作用仅部分依赖于其作为通道的功能。我们的结果为深入了解ANO1在细胞中的调控机制提供了动力，并为ANO1扩增的癌症的抗肿瘤治疗引入了一种新的靶向方法。
Background: The calcium-activated chloride channel ANO1 is highly expressed in cancer. Results: Inhibition of ANO1 activity alone is not sufficient to inhibit cancer cell proliferation, suggesting a novel function of ANO1 protein in cancer. Conclusion: The ANO1 inhibitor CaCCinh-A01 inhibits cancer cell proliferation by facilitating degradation of ANO1. Significance: Our results may provide a new targeting approach for antitumor therapy in ANO1-amplified cancers. 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.