title: Novel Protein Disulfide Isomerase Inhibitor with Anticancer Activity in Multiple Myeloma.
abstract: Multiple myeloma cells secrete more disulfide bond-rich proteins than any other mammalian cell. Thus, inhibition of protein disulfide isomerases (PDI) required for protein folding in the endoplasmic reticulum (ER) should increase ER stress beyond repair in this incurable cancer. Here, we report the mechanistically unbiased discovery of a novel PDI-inhibiting compound with antimyeloma activity. We screened a 30,355 small-molecule library using a multilayered multiple myeloma cell-based cytotoxicity assay that modeled disease niche, normal liver, kidney, and bone marrow. CCF642, a bone marrow-sparing compound, exhibited a submicromolar IC50 in 10 of 10 multiple myeloma cell lines. An active biotinylated analog of CCF642 defined binding to the PDI isoenzymes A1, A3, and A4 in MM cells. In vitro, CCF642 inhibited PDI reductase activity about 100-fold more potently than the structurally distinct established inhibitors PACMA 31 and LOC14. Computational modeling suggested a novel covalent binding mode in active-site CGHCK motifs. Remarkably, without any further chemistry optimization, CCF642 displayed potent efficacy in an aggressive syngeneic mouse model of multiple myeloma and prolonged the lifespan of C57BL/KaLwRij mice engrafted with 5TGM1-luc myeloma, an effect comparable to the first-line multiple myeloma therapeutic bortezomib. Consistent with PDI inhibition, CCF642 caused acute ER stress in multiple myeloma cells accompanied by apoptosis-inducing calcium release. Overall, our results provide an illustration of the utility of simple in vivo simulations as part of a drug discovery effort, along with a sound preclinical rationale to develop a new small-molecule therapeutic to treat multiple myeloma. Cancer Res; 76(11); 3340-50. ©2016 AACR.
authors.affiliation: Department of Translational Hematology & Oncology Research, Cleveland Clinic, Cleveland, Ohio.
authors.forename: Sergei
authors.initials: S
authors.lastname: Vatolin
authors.affiliation: Department of Translational Hematology & Oncology Research, Cleveland Clinic, Cleveland, Ohio.
authors.forename: James G
authors.initials: JG
authors.lastname: Phillips
authors.affiliation: Department of Translational Hematology & Oncology Research, Cleveland Clinic, Cleveland, Ohio.
authors.forename: Babal K
authors.initials: BK
authors.lastname: Jha
authors.affiliation: Cornell University, Ithaca, New York.
authors.forename: Shravya
authors.initials: S
authors.lastname: Govindgari
authors.affiliation: Cleveland Clinic Lerner College of Medicine, Case Western Reserve University, Cleveland, Ohio.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Hu
authors.affiliation: Department of Translational Hematology & Oncology Research, Cleveland Clinic, Cleveland, Ohio.
authors.forename: Dale
authors.initials: D
authors.lastname: Grabowski
authors.affiliation: Department of Translational Hematology & Oncology Research, Cleveland Clinic, Cleveland, Ohio.
authors.forename: Yvonne
authors.initials: Y
authors.lastname: Parker
authors.affiliation: Department of Translational Hematology & Oncology Research, Cleveland Clinic, Cleveland, Ohio. Case Comprehensive Cancer Center, Case Western Reserve University, Cleveland, Ohio.
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Lindner
authors.affiliation: Division of Hematology & Oncology, University Hospitals of Cleveland, Cleveland, Ohio.
authors.forename: Fei
authors.initials: F
authors.lastname: Zhong
authors.affiliation: Case Comprehensive Cancer Center, Case Western Reserve University, Cleveland, Ohio. Division of Hematology & Oncology, University Hospitals of Cleveland, Cleveland, Ohio.
authors.forename: Clark W
authors.initials: CW
authors.lastname: Distelhorst
authors.affiliation: Case Comprehensive Cancer Center, Case Western Reserve University, Cleveland, Ohio. Department of Hematology & Medical Oncology, Cleveland Clinic, Cleveland, Ohio.
authors.forename: Mitchell R
authors.initials: MR
authors.lastname: Smith
authors.affiliation: Department of Clinical Pathology, Cleveland Clinic, Cleveland, Ohio.
authors.forename: Claudiu
authors.initials: C
authors.lastname: Cotta
authors.affiliation: Department of Chemistry, Cleveland State University, Cleveland, Ohio.
authors.forename: Yan
authors.initials: Y
authors.lastname: Xu
authors.affiliation: Department of Chemistry, Cleveland State University, Cleveland, Ohio.
authors.forename: Sujatha
authors.initials: S
authors.lastname: Chilakala
authors.affiliation: University of Chicago, Chicago, Illinois.
authors.forename: Rebecca R
authors.initials: RR
authors.lastname: Kuang
authors.affiliation: Emory University, Atlanta, Georgia.
authors.forename: Samantha
authors.initials: S
authors.lastname: Tall
authors.affiliation: Department of Translational Hematology & Oncology Research, Cleveland Clinic, Cleveland, Ohio. Case Comprehensive Cancer Center, Case Western Reserve University, Cleveland, Ohio. Department of Hematology & Medical Oncology, Cleveland Clinic, Cleveland, Ohio. reuf@ccf.org.
authors.forename: Frederic J
authors.initials: FJ
authors.lastname: Reu
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D001665:Binding Sites; D015153:Blotting, Western; D049109:Cell Proliferation / Q000187:drug effects; D004721:Endoplasmic Reticulum / Q000187:drug effects / Q000201:enzymology; D059865:Endoplasmic Reticulum Stress / Q000187:drug effects*; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D006801:Humans; D051379:Mice; D008810:Mice, Inbred C57BL; D009101:Multiple Myeloma / Q000188:drug therapy / Q000201:enzymology / Q000473:pathology*; D010084:Oxidation-Reduction; D011487:Protein Conformation; D019704:Protein Disulfide-Isomerases / Q000037:antagonists & inhibitors* / Q000378:metabolism; D053778:Thiazolidines / Q000494:pharmacology*; D013871:Thiones / Q000494:pharmacology*; D014407:Tumor Cells, Cultured; D023041:Xenograft Model Antitumor Assays
chemical_list: D000970:Antineoplastic Agents; C000621540:CCF642; D004791:Enzyme Inhibitors; D053778:Thiazolidines; D013871:Thiones; D019704:Protein Disulfide-Isomerases