title: Identification of a novel BCL2-specific inhibitor that binds predominantly to the BH1 domain.
abstract: The antiapoptotic protein BCL2 is overexpressed in several cancers and contributes to prolonged cell survival and chemoresistance, lending itself as an excellent target for cancer therapy. Here, we report the design, synthesis, and characterization of Disarib, a novel BCL2 inhibitor. Disarib showed selective cytotoxicity in BCL2 high cancer cell lines, and CLL patient primary cells, as compared to BCL2 low cell lines. BCL2 knockdown in cells rendered remarkable resistance to Disarib, while sensitivity was regained upon its ectopic expression, establishing target specificity. In silico, biochemical and biophysical studies demonstrated strong affinity of Disarib to BCL2, but not to other antiapoptotic BCL2 family members viz., BCL-xL, BCL2A1 etc. Interestingly, biophysical studies showed that BH1 domain deletion mutant demonstrated ~ 67-fold reduction in BCL2-Disarib interaction, while it was only ~ 20-fold in the case of BH3 deletion mutant, suggesting predominant involvement of the BH1 domain for Disarib binding. Thus, we report identification of a novel BCL2 inhibitor with a unique mechanism of BCL2 inhibition, as opposed to the well-studied BH3 domain targeting.
authors.affiliation: Department of Biochemistry, Indian Institute of Science, Bangalore, India.
authors.forename: Divyaanka
authors.initials: D
authors.lastname: Iyer
authors.affiliation: Department of Biochemistry, Indian Institute of Science, Bangalore, India.
authors.forename: Supriya V
authors.initials: SV
authors.lastname: Vartak
authors.affiliation: Molecular Biophysics Unit, Indian Institute of Science, Bangalore, India.
authors.forename: Archita
authors.initials: A
authors.lastname: Mishra
authors.affiliation: Institute of Bioinformatics and Applied Biotechnology, Electronics City, Bangalore, India.
authors.forename: Gunaseelan
authors.initials: G
authors.lastname: Goldsmith
authors.affiliation: Department of Pharmaceutical Chemistry, KLE University's College of Pharmacy, Bangalore, India.
authors.forename: Sujeet
authors.initials: S
authors.lastname: Kumar
authors.affiliation: Department of Biochemistry, Indian Institute of Science, Bangalore, India.
authors.forename: Mrinal
authors.initials: M
authors.lastname: Srivastava
authors.affiliation: Department of Biochemistry, Indian Institute of Science, Bangalore, India.
authors.forename: Mahesh
authors.initials: M
authors.lastname: Hegde
authors.affiliation: Department of Biochemistry, Indian Institute of Science, Bangalore, India.|Institute of Bioinformatics and Applied Biotechnology, Electronics City, Bangalore, India.
authors.forename: Vidya
authors.initials: V
authors.lastname: Gopalakrishnan
authors.affiliation: Haematology, Department of Molecular and Clinical Cancer Medicine University of Liverpool, UK.
authors.forename: Mark
authors.initials: M
authors.lastname: Glenn
authors.affiliation: Institute of Bioinformatics and Applied Biotechnology, Electronics City, Bangalore, India.
authors.forename: Mahesh
authors.initials: M
authors.lastname: Velusamy
authors.affiliation: Institute of Bioinformatics and Applied Biotechnology, Electronics City, Bangalore, India.
authors.forename: Bibha
authors.initials: B
authors.lastname: Choudhary
authors.affiliation: Haematology, Department of Molecular and Clinical Cancer Medicine University of Liverpool, UK.
authors.forename: Nagesh
authors.initials: N
authors.lastname: Kalakonda
authors.affiliation: Department of Pharmaceutical Chemistry, KLE University's College of Pharmacy, Bangalore, India.
authors.forename: Subhas S
authors.initials: SS
authors.lastname: Karki
authors.affiliation: Molecular Biophysics Unit, Indian Institute of Science, Bangalore, India.
authors.forename: Avadhesha
authors.initials: A
authors.lastname: Surolia
authors.affiliation: Department of Biochemistry, Indian Institute of Science, Bangalore, India. sathees@biochem.iisc.ernet.in.
authors.forename: Sathees C
authors.initials: SC
authors.lastname: Raghavan
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000737:chemistry / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D001665:Binding Sites; D055592:Biophysical Phenomena; D045744:Cell Line, Tumor; D015195:Drug Design; D019008:Drug Resistance, Neoplasm; D005260:Female; D055785:Gene Knockdown Techniques; D006801:Humans; D007211:Indoles / Q000737:chemistry / Q000494:pharmacology*; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology; D051379:Mice; D008958:Models, Molecular; D015394:Molecular Structure; D000072417:Protein Domains; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000378:metabolism; D013830:Thiadiazoles / Q000737:chemistry / Q000494:pharmacology*; D014407:Tumor Cells, Cultured
chemical_list: D000970:Antineoplastic Agents; C000595707:BCL2 protein, human; D007211:Indoles; D019253:Proto-Oncogene Proteins c-bcl-2; D013830:Thiadiazoles; C000618298:disarib
keywords: apoptosis; cancer therapeutics; cell death; chemotherapy; genomic instability; leukemia; molecular docking; small molecule inhibitor