Telethon Institute of Genetics and Medicine (TIGEM), Pozzuoli, Italy.
Department of Translational Medical Sciences (DISMET), University of Naples "Federico II", Naples, Italy.
Br J Pharmacol. 2023 Mar;180(6):775-785. doi: 10.1111/bph.15995. Epub 2022 Dec 18.
Pharmacological inhibitors of TMEM16A (ANO1), a Ca -activated Cl channel, are important tools of research and possible therapeutic agents acting on smooth muscle, airway epithelia and cancer cells. We tested a panel of TMEM16A inhibitors, including CaCC -A01, niclosamide, MONNA, Ani9 and niflumic acid, to evaluate their possible effect on intracellular Ca .
We recorded cytosolic Ca increase elicited with UTP, ionomycin or IP uncaging.
Unexpectedly, we found that all compounds, except for Ani9, markedly decreased intracellular Ca elevation induced by stimuli acting on intracellular Ca stores. These effects were similarly observed in cells with and without TMEM16A expression. We investigated in more detail the mechanism of action of niclosamide and CaCC -A01. Acute addition of niclosamide directly increased intracellular Ca , an activity consistent with inhibition of the SERCA pump. In contrast to niclosamide, CaCC -A01 did not elevate intracellular Ca , thus implying a different mechanism of action, possibly a block of inositol triphosphate receptors.
Most TMEM16A inhibitors are endowed with indirect effects mediated by alteration of intracellular Ca handling, which may in part preclude their use as TMEM16A research tools.
TMEM16A（ANO1）是一种 Ca2+激活的氯离子通道，其药理学抑制剂是研究的重要工具，并且可能成为作用于平滑肌、气道上皮和癌细胞的治疗药物。我们测试了一组 TMEM16A 抑制剂，包括 CaCC-A01、尼氯柳胺、MONNA、Ani9 和硝苯地平，以评估它们对细胞内 Ca2+的可能影响。
我们记录了 UTP、离子霉素或 IP 光解引发的细胞内 Ca2+增加。
出乎意料的是，我们发现除了 Ani9 之外，所有化合物都明显降低了细胞内 Ca2+的升高，这些化合物通过作用于细胞内 Ca2+库的刺激来诱导。这些作用在表达和不表达 TMEM16A 的细胞中都有类似的观察。我们更详细地研究了尼氯柳胺和 CaCC-A01 的作用机制。尼氯柳胺的急性添加直接增加了细胞内 Ca2+，这一活性与抑制 SERCA 泵一致。与尼氯柳胺不同，CaCC-A01 没有升高细胞内 Ca2+，因此暗示了不同的作用机制，可能是肌醇三磷酸受体的阻断。
大多数 TMEM16A 抑制剂具有通过改变细胞内 Ca2+处理介导的间接作用，这可能在一定程度上排除了它们作为 TMEM16A 研究工具的使用。
