title: Small molecule-facilitated degradation of ANO1 protein: a new targeting approach for anticancer therapeutics.
abstract: 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.
authors.affiliation: Novartis Institutes for Biomedical Research, Cambridge, Massachusetts 02139.
authors.forename: Anke
authors.initials: A
authors.lastname: Bill
authors.affiliation: Novartis Institutes for Biomedical Research, Cambridge, Massachusetts 02139.
authors.forename: Michelle Lynn
authors.initials: ML
authors.lastname: Hall
authors.affiliation: Novartis Institutes for Biomedical Research, Cambridge, Massachusetts 02139.
authors.forename: Jason
authors.initials: J
authors.lastname: Borawski
authors.affiliation: Novartis Institutes for Biomedical Research, Horsham, West Sussex, RH12 5AB, United Kingdom, and.
authors.forename: Catherine
authors.initials: C
authors.lastname: Hodgson
authors.affiliation: Novartis Institutes for Biomedical Research, Cambridge, Massachusetts 02139.
authors.forename: Jeremy
authors.initials: J
authors.lastname: Jenkins
authors.affiliation: the Novartis Institutes for Biomedical Research, Basel CH-4002, Switzerland.
authors.forename: Philippe
authors.initials: P
authors.lastname: Piechon
authors.affiliation: Novartis Institutes for Biomedical Research, Horsham, West Sussex, RH12 5AB, United Kingdom, and.
authors.forename: Oana
authors.initials: O
authors.lastname: Popa
authors.affiliation: Novartis Institutes for Biomedical Research, Cambridge, Massachusetts 02139.
authors.forename: Christopher
authors.initials: C
authors.lastname: Rothwell
authors.affiliation: Novartis Institutes for Biomedical Research, Horsham, West Sussex, RH12 5AB, United Kingdom, and.
authors.forename: Pamela
authors.initials: P
authors.lastname: Tranter
authors.affiliation: Novartis Institutes for Biomedical Research, Cambridge, Massachusetts 02139.
authors.forename: Scott
authors.initials: S
authors.lastname: Tria
authors.affiliation: the Novartis Institutes for Biomedical Research, Basel CH-4002, Switzerland.
authors.forename: Trixie
authors.initials: T
authors.lastname: Wagner
authors.affiliation: Novartis Institutes for Biomedical Research, Cambridge, Massachusetts 02139.
authors.forename: Lewis
authors.initials: L
authors.lastname: Whitehead
authors.affiliation: Novartis Institutes for Biomedical Research, Cambridge, Massachusetts 02139,. Electronic address: alex.gaither@novartis.com.
authors.forename: L Alex
authors.initials: LA
authors.lastname: Gaither
mesh_terms: D000075369:Anoctamin-1; D000970:Antineoplastic Agents / Q000737:chemistry* / Q000494:pharmacology*; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D018118:Chloride Channels / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism*; D016503:Drug Delivery Systems; D006801:Humans; D009363:Neoplasm Proteins / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism*; D009369:Neoplasms / Q000188:drug therapy* / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D059748:Proteolysis / Q000187:drug effects*
chemical_list: C476213:ANO1 protein, human; D000075369:Anoctamin-1; D000970:Antineoplastic Agents; D018118:Chloride Channels; D009363:Neoplasm Proteins
keywords: Anticancer Drug; Cancer Biology; Cancer Therapy; Chloride Channels; Computational Biology; ER-associated Degradation; Ion Channels; Molecular Modeling; Protein Degradation; Small Molecules