Anoctamin-1 (ANO1), also known as transmembrane protein 16A (TMEM16A), is identified as a Ca²⁺-activated Cl⁻ channel that is expressed in many organs and tissues. It is involved in numerous major physiological functions and especially in tumor growth. By screening 530 natural compounds, we identified cepharanthine as a potent blocker of ANO1 channels with an IC₅₀ of 11.2 ± 0.9 μM and E_max of 92.7 ± 1.7%. The Lys³⁸⁴, Arg⁵³⁵, Thr⁵³⁹, and Glu⁶²⁴ in ANO1 are critical for the inhibitory effect of cepharanthine. Similar to its effect on ANO1, cepharanthine inhibits ANO2, the closest analog of TMEM16A. In contrast, up to 30 μM of cepharanthine showed limited inhibitory effects on recombinant ANO6 and bestrophin-1-encoded Ca²⁺-activated Cl⁻ currents, but it showed no effects on endogenous volume-regulated anion currents (VRAC). Cepharanthine could also potently suppress endogenous ANO1 currents, significantly inhibit cell proliferation and migration, and induce apoptosis in LA795 lung adenocarcinoma cells. Moreover, animal experiments have shown that cepharanthine can dramatically inhibit the growth of xenograft tumors in mice. The high specificity provided by cepharanthine could be an important foundation for future studies of the physiological role of ANO1 channels, and these findings may reveal a new mechanism of its anticancer effect.

Anoctamin-1 (ANO1)，也称为跨膜蛋白 16A (TMEM16A)，被鉴定为 Ca ²⁺激活的 Cl ^-通道，在许多器官和组织中表达。它涉及许多主要的生理功能，尤其是在肿瘤生长中。通过筛选 530 种天然化合物，我们确定头孢氨苄是 ANO1 通道的有效阻断剂，其 IC ₅₀为 11.2 ± 0.9 μM，E _max为 92.7 ± 1.7%。Lys ³⁸⁴、Arg ⁵³⁵、Thr ⁵³⁹和 Glu ⁶²⁴ANO1 中的 cepharanthine 的抑制作用至关重要。与其对 ANO1 的影响相似，头孢氨苄抑制 ANO2，这是与 TMEM16A 最接近的类似物。相比之下，高达 30 μM 的头孢氨苄对重组 ANO6 和 bestrophin-1 编码的 Ca ²⁺激活的 Cl ^-显示出有限的抑制作用电流，但它对内源性体积调节阴离子电流 (VRAC) 没有影响。Cepharanthine 还可以有效抑制内源性 ANO1 电流，显着抑制细胞增殖和迁移，并诱导 LA795 肺腺癌细胞凋亡。此外，动物实验表明，cepharanthine 可以显着抑制小鼠异种移植肿瘤的生长。cepharanthine 提供的高特异性可能是未来研究 ANO1 通道生理作用的重要基础，这些发现可能揭示其抗癌作用的新机制。