Pharmacological targeting of ANO1/TMEM16A in cancer: from channel inhibition to protein downregulation.

Abstract

Anoctamin 1 (ANO1/TMEM16A) is a calcium-activated chloride channel increasingly recognized as a compelling pharmacological target in oncology. Beyond its role in chloride flux, ANO1 has also been proposed to exert signaling-associated or scaffold-like functions in selected malignancies, including head and neck, breast, and lung cancers. Although pharmacological studies have progressed from broad inhibitors to selective probes and natural products, a critical need has emerged for a rigorous standard to evaluate these agents. A central challenge is distinguishing acute conductance blockade from protein-level downregulation, as these mechanisms may produce distinct biological outcomes. Channel inhibition suppresses ion flux while potentially leaving ANO1-associated protein complexes intact, whereas protein reduction may affect both conductance-dependent and signaling-associated functions; however, the extent to which these functions are mechanistically independent remains incompletely established. Consequently, regulation of ANO1 stability is emerging as a promising therapeutic strategy in tumors with high ANO1 expression and epidermal growth factor receptor (EGFR) activation. However, in clinically relevant EGFR-mutant non-small cell lung cancer models, the role of ANO1 should be interpreted cautiously. Current evidence supports ANO1 as a context-dependent preclinical vulnerability rather than an established mechanism for overcoming osimertinib resistance. To address methodological inconsistencies in the field, this review summarizes ANO1 cancer pharmacology and proposes a conservative operational evidence framework. By establishing strict validation criteria, we classify ANO1 modulators into functional inhibitors, dual modulators, protein-level downregulators, and protein-stability modulators while defining evidence requirements for bona fide targeted degrader designation.