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Parchure A, Tian M, Stalder D, Boyer CK, Bearrows SC, Rohli KE, Zhang J, Rivera-Molina F, Ramazanov BR, Mahata SK, Wang Y, Stephens SB, Gershlick DC, von Blume J. Liquid-liquid phase separation facilitates the biogenesis of secretory storage granules. J Cell Biol 2022; 221:e202206132. [PMID: 36173346 PMCID: PMC9526250 DOI: 10.1083/jcb.202206132] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 08/30/2022] [Accepted: 09/01/2022] [Indexed: 02/03/2023] Open
Abstract
Insulin is synthesized by pancreatic β-cells and stored into secretory granules (SGs). SGs fuse with the plasma membrane in response to a stimulus and deliver insulin to the bloodstream. The mechanism of how proinsulin and its processing enzymes are sorted and targeted from the trans-Golgi network (TGN) to SGs remains mysterious. No cargo receptor for proinsulin has been identified. Here, we show that chromogranin (CG) proteins undergo liquid-liquid phase separation (LLPS) at a mildly acidic pH in the lumen of the TGN, and recruit clients like proinsulin to the condensates. Client selectivity is sequence-independent but based on the concentration of the client molecules in the TGN. We propose that the TGN provides the milieu for converting CGs into a "cargo sponge" leading to partitioning of client molecules, thus facilitating receptor-independent client sorting. These findings provide a new receptor-independent sorting model in β-cells and many other cell types and therefore represent an innovation in the field of membrane trafficking.
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Affiliation(s)
- Anup Parchure
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT
| | - Meng Tian
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT
| | - Danièle Stalder
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, UK
| | - Cierra K. Boyer
- Departments of Pharmacology and Neuroscience, Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA
- Internal Medicine, Division of Endocrinology and Metabolism, University of Iowa, Iowa City, IA
| | - Shelby C. Bearrows
- Departments of Pharmacology and Neuroscience, Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA
- Internal Medicine, Division of Endocrinology and Metabolism, University of Iowa, Iowa City, IA
| | - Kristen E. Rohli
- Departments of Pharmacology and Neuroscience, Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA
- Internal Medicine, Division of Endocrinology and Metabolism, University of Iowa, Iowa City, IA
| | - Jianchao Zhang
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI
- Department of Neurology, University of Michigan School of Medicine, Ann Arbor, MI
| | - Felix Rivera-Molina
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT
| | - Bulat R. Ramazanov
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT
| | - Sushil K. Mahata
- Department of Medicine, University of California San Diego, La Jolla, CA
- VA San Diego Healthcare System, San Diego, CA
| | - Yanzhuang Wang
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI
- Department of Neurology, University of Michigan School of Medicine, Ann Arbor, MI
| | - Samuel B. Stephens
- Departments of Pharmacology and Neuroscience, Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA
| | - David C. Gershlick
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, UK
| | - Julia von Blume
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT
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2
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Rohli KE, Boyer CK, Bearrows SC, Moyer MR, Elison WS, Bauchle CJ, Blom SE, Zhang J, Wang Y, Stephens SB. ER Redox Homeostasis Regulates Proinsulin Trafficking and Insulin Granule Formation in the Pancreatic Islet β-Cell. Function (Oxf) 2022; 3:zqac051. [PMID: 36325514 PMCID: PMC9614934 DOI: 10.1093/function/zqac051] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Revised: 09/11/2022] [Accepted: 09/21/2022] [Indexed: 01/07/2023] Open
Abstract
Defects in the pancreatic β-cell's secretion system are well-described in type 2 diabetes (T2D) and include impaired proinsulin processing and a deficit in mature insulin-containing secretory granules; however, the cellular mechanisms underlying these defects remain poorly understood. To address this, we used an in situ fluorescent pulse-chase strategy to study proinsulin trafficking. We show that insulin granule formation and the appearance of nascent granules at the plasma membrane are decreased in rodent and cell culture models of prediabetes and hyperglycemia. Moreover, we link the defect in insulin granule formation to an early trafficking delay in endoplasmic reticulum (ER) export of proinsulin, which is independent of overt ER stress. Using a ratiometric redox sensor, we show that the ER becomes hyperoxidized in β-cells from a dietary model of rodent prediabetes and that addition of reducing equivalents restores ER export of proinsulin and insulin granule formation and partially restores β-cell function. Together, these data identify a critical role for the regulation of ER redox homeostasis in proinsulin trafficking and suggest that alterations in ER redox poise directly contribute to the decline in insulin granule production in T2D. This model highlights a critical link between alterations in ER redox and ER function with defects in proinsulin trafficking in T2D. Hyperoxidation of the ER lumen, shown as hydrogen peroxide, impairs proinsulin folding and disulfide bond formation that prevents efficient exit of proinsulin from the ER to the Golgi. This trafficking defect limits available proinsulin for the formation of insulin secretory granules during the development of T2D.
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Affiliation(s)
- Kristen E Rohli
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA 52242, USA
- Interdisciplinary Graduate Program in Genetics, University of Iowa, Iowa City, IA 52242, USA
- Department of Internal Medicine, Division of Endocrinology and Metabolism, University of Iowa, Iowa City, IA 52242, USA
| | - Cierra K Boyer
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA 52242, USA
- Department of Pharmacology, University of Iowa, Iowa City, IA 52242, USA
| | - Shelby C Bearrows
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA 52242, USA
- Department of Internal Medicine, Division of Endocrinology and Metabolism, University of Iowa, Iowa City, IA 52242, USA
| | - Marshall R Moyer
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA 52242, USA
- Department of Internal Medicine, Division of Endocrinology and Metabolism, University of Iowa, Iowa City, IA 52242, USA
| | - Weston S Elison
- Department of Nutrition, Dietetics, and Food Science, Brigham Young University, Provo, UT 84602, USA
| | - Casey J Bauchle
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA 52242, USA
- Department of Internal Medicine, Division of Endocrinology and Metabolism, University of Iowa, Iowa City, IA 52242, USA
| | - Sandra E Blom
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA 52242, USA
- Department of Internal Medicine, Division of Endocrinology and Metabolism, University of Iowa, Iowa City, IA 52242, USA
| | - Jianchao Zhang
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48103, USA
| | - Yanzhuang Wang
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48103, USA
- Department of Neurology, School of Medicine, University of Michigan, Ann Arbor, MI 48103, USA
| | - Samuel B Stephens
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA 52242, USA
- Interdisciplinary Graduate Program in Genetics, University of Iowa, Iowa City, IA 52242, USA
- Department of Internal Medicine, Division of Endocrinology and Metabolism, University of Iowa, Iowa City, IA 52242, USA
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3
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Walter ND, Born SEM, Robertson GT, Reichlen M, Dide-Agossou C, Ektnitphong VA, Rossmassler K, Ramey ME, Bauman AA, Ozols V, Bearrows SC, Schoolnik G, Dolganov G, Garcia B, Musisi E, Worodria W, Huang L, Davis JL, Nguyen NV, Nguyen HV, Nguyen ATV, Phan H, Wilusz C, Podell BK, Sanoussi ND, de Jong BC, Merle CS, Affolabi D, McIlleron H, Garcia-Cremades M, Maidji E, Eshun-Wilson F, Aguilar-Rodriguez B, Karthikeyan D, Mdluli K, Bansbach C, Lenaerts AJ, Savic RM, Nahid P, Vásquez JJ, Voskuil MI. Mycobacterium tuberculosis precursor rRNA as a measure of treatment-shortening activity of drugs and regimens. Nat Commun 2021; 12:2899. [PMID: 34006838 PMCID: PMC8131613 DOI: 10.1038/s41467-021-22833-6] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Accepted: 03/26/2021] [Indexed: 01/01/2023] Open
Abstract
There is urgent need for new drug regimens that more rapidly cure tuberculosis (TB). Existing TB drugs and regimens vary in treatment-shortening activity, but the molecular basis of these differences is unclear, and no existing assay directly quantifies the ability of a drug or regimen to shorten treatment. Here, we show that drugs historically classified as sterilizing and non-sterilizing have distinct impacts on a fundamental aspect of Mycobacterium tuberculosis physiology: ribosomal RNA (rRNA) synthesis. In culture, in mice, and in human studies, measurement of precursor rRNA reveals that sterilizing drugs and highly effective drug regimens profoundly suppress M. tuberculosis rRNA synthesis, whereas non-sterilizing drugs and weaker regimens do not. The rRNA synthesis ratio provides a readout of drug effect that is orthogonal to traditional measures of bacterial burden. We propose that this metric of drug activity may accelerate the development of shorter TB regimens.
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Affiliation(s)
- Nicholas D Walter
- Rocky Mountain Regional VA Medical Center, Aurora, CO, USA.
- Division of Pulmonary Sciences and Critical Care Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, USA.
- Consortium for Applied Microbial Metrics, Aurora, CO, USA.
| | - Sarah E M Born
- Department of Immunology and Microbiology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Gregory T Robertson
- Consortium for Applied Microbial Metrics, Aurora, CO, USA
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, CO, USA
| | - Matthew Reichlen
- Department of Immunology and Microbiology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | | | - Victoria A Ektnitphong
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, CO, USA
| | - Karen Rossmassler
- Rocky Mountain Regional VA Medical Center, Aurora, CO, USA
- Division of Pulmonary Sciences and Critical Care Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Michelle E Ramey
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, CO, USA
| | - Allison A Bauman
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, CO, USA
| | - Victor Ozols
- Rocky Mountain Regional VA Medical Center, Aurora, CO, USA
- Division of Pulmonary Sciences and Critical Care Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Shelby C Bearrows
- Rocky Mountain Regional VA Medical Center, Aurora, CO, USA
- Division of Pulmonary Sciences and Critical Care Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Gary Schoolnik
- Division of Infectious Diseases and Geographic Medicine, Stanford University, Palo Alto, CA, USA
| | - Gregory Dolganov
- Division of Infectious Diseases and Geographic Medicine, Stanford University, Palo Alto, CA, USA
| | - Benjamin Garcia
- Integrated Center for Genes, Environment, and Health, National Jewish Health, Denver, CO, USA
- Computational Bioscience Program, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Emmanuel Musisi
- Infectious Disease Research Collaboration, Kampala, Uganda
- Department of Biochemistry, Makerere University, Kampala, Uganda
| | | | - Laurence Huang
- Division of Pulmonary and Critical Care Medicine, University of California San Francisco, San Francisco, CA, USA
- Division of HIV, Infectious Diseases and Global Medicine, University of California San Francisco, San Francisco, CA, USA
- Zuckerberg San Francisco General Hospital, San Francisco, CA, USA
| | - J Lucian Davis
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT, USA
- Pulmonary, Critical Care, and Sleep Medicine Section, Yale School of Medicine, New Haven, CT, USA
| | - Nhung V Nguyen
- Vietnam National TB Programme/UCSF Research Collaboration Unit, Hanoi, Vietnam
| | - Hung V Nguyen
- Vietnam National TB Programme/UCSF Research Collaboration Unit, Hanoi, Vietnam
| | - Anh T V Nguyen
- Vietnam National TB Programme/UCSF Research Collaboration Unit, Hanoi, Vietnam
| | - Ha Phan
- Vietnam National TB Programme/UCSF Research Collaboration Unit, Hanoi, Vietnam
| | - Carol Wilusz
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, CO, USA
| | - Brendan K Podell
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, CO, USA
| | | | - Bouke C de Jong
- Mycobacteriology Unit, Institute of Tropical Medicine, Antwerp, Belgium
| | - Corinne S Merle
- London School of Hygiene and Tropical Medicine, London, UK
- UNICEF/UNDP/World Bank/WHO Special Programme on Research and Training in Tropical Disease, Geneva CH, Switzerland
| | | | - Helen McIlleron
- Division of Clinical Pharmacology, University of Cape Town, Cape Town, South Africa
- Wellcome Centre for Infectious Diseases Research in Africa, Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Cape Town, South Africa
| | - Maria Garcia-Cremades
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, CA, USA
| | - Ekaterina Maidji
- Division of Experimental Medicine, University of California San Francisco, San Francisco, CA, USA
| | - Franceen Eshun-Wilson
- Division of Experimental Medicine, University of California San Francisco, San Francisco, CA, USA
| | | | - Dhuvarakesh Karthikeyan
- Division of Experimental Medicine, University of California San Francisco, San Francisco, CA, USA
| | - Khisimuzi Mdluli
- Bill & Melinda Gates Medical Research Institute, Cambridge, MA, USA
| | | | - Anne J Lenaerts
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, CO, USA
| | - Radojka M Savic
- Consortium for Applied Microbial Metrics, Aurora, CO, USA
- Division of Pulmonary and Critical Care Medicine, University of California San Francisco, San Francisco, CA, USA
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, CA, USA
- UCSF Center for Tuberculosis, University of California, San Francisco, CA, USA
| | - Payam Nahid
- Consortium for Applied Microbial Metrics, Aurora, CO, USA
- Division of Pulmonary and Critical Care Medicine, University of California San Francisco, San Francisco, CA, USA
- Zuckerberg San Francisco General Hospital, San Francisco, CA, USA
- Vietnam National TB Programme/UCSF Research Collaboration Unit, Hanoi, Vietnam
- UCSF Center for Tuberculosis, University of California, San Francisco, CA, USA
| | - Joshua J Vásquez
- Consortium for Applied Microbial Metrics, Aurora, CO, USA
- Division of Pulmonary and Critical Care Medicine, University of California San Francisco, San Francisco, CA, USA
- Zuckerberg San Francisco General Hospital, San Francisco, CA, USA
- Division of Experimental Medicine, University of California San Francisco, San Francisco, CA, USA
- UCSF Center for Tuberculosis, University of California, San Francisco, CA, USA
| | - Martin I Voskuil
- Consortium for Applied Microbial Metrics, Aurora, CO, USA.
- Department of Immunology and Microbiology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA.
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4
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Walker ZJ, Idler BM, Davis LN, Stevens BM, VanWyngarden MJ, Ohlstrom D, Bearrows SC, Hammes A, Smith CA, Jordan CT, Mark TM, Forsberg PA, Sherbenou DW. Exploiting Protein Translation Dependence in Multiple Myeloma with Omacetaxine-Based Therapy. Clin Cancer Res 2020; 27:819-830. [PMID: 33109736 DOI: 10.1158/1078-0432.ccr-20-2246] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 08/18/2020] [Accepted: 10/22/2020] [Indexed: 11/16/2022]
Abstract
PURPOSE The prognosis of patients with multiple myeloma who are resistant to proteasome inhibitors, immunomodulatory drugs (IMiD), and daratumumab is extremely poor. Even B-cell maturation antigen-specific chimeric antigen receptor T-cell therapies provide only a temporary benefit before patients succumb to their disease. In this article, we interrogate the unique sensitivity of multiple myeloma cells to the alternative strategy of blocking protein translation with omacetaxine. EXPERIMENTAL DESIGN We determined protein translation levels (n = 17) and sensitivity to omacetaxine (n = 51) of primary multiple myeloma patient samples. Synergy was evaluated between omacetaxine and IMiDs in vitro, ex vivo, and in vivo. Underlying mechanism was investigated via proteomic analysis. RESULTS Almost universally, primary patient multiple myeloma cells exhibit >2.5-fold increased rates of protein translation compared with normal marrow cells. Ex vivo treatment with omacetaxine resulted in >50% reduction in viable multiple myeloma cells. In this cohort, high levels of translation serve as a biomarker for patient multiple myeloma cell sensitivity to omacetaxine. Unexpectedly, omacetaxine demonstrated synergy with IMiDs in multiple myeloma cell lines in vitro. In addition, in an IMiD-resistant relapsed patient sample, omacetaxine/IMiD combination treatment resensitized the multiple myeloma cells to the IMiD. Proteomic analysis found that the omacetaxine/IMiD combination treatment produced a double-hit on the IRF4/c-MYC pathway, which is critical to multiple myeloma survival. CONCLUSIONS Overall, protein translation inhibitors represent a potential new drug class for myeloma treatment and provide a rationale for conducting clinical trials with omacetaxine alone and in combination with IMiDs for patients with relapsed/refractory multiple myeloma.
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Affiliation(s)
- Zachary J Walker
- Division of Hematology, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Beau M Idler
- Division of Hematology, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Lorraine N Davis
- Division of Hematology, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Brett M Stevens
- Division of Hematology, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Michael J VanWyngarden
- Division of Hematology, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Denis Ohlstrom
- Biomedical Sciences and Biotechnology, Graduate School, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Shelby C Bearrows
- Division of Hematology, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Andrew Hammes
- Center for Innovative Design and Analysis, Department of Biostatistics and Informatics, Colorado School of Public Health, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Clayton A Smith
- Division of Hematology, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado.,University of Colorado Cancer Center, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Craig T Jordan
- Division of Hematology, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado.,University of Colorado Cancer Center, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Tomer M Mark
- Division of Hematology, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Peter A Forsberg
- Division of Hematology, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Daniel W Sherbenou
- Division of Hematology, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado. .,University of Colorado Cancer Center, University of Colorado Anschutz Medical Campus, Aurora, Colorado
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5
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Sherbenou DW, Su Y, Behrens CR, Aftab BT, Perez de Acha O, Murnane M, Bearrows SC, Hann BC, Wolf JL, Martin TG, Liu B. Potent Activity of an Anti-ICAM1 Antibody-Drug Conjugate against Multiple Myeloma. Clin Cancer Res 2020; 26:6028-6038. [PMID: 32917735 DOI: 10.1158/1078-0432.ccr-20-0400] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 07/15/2020] [Accepted: 09/08/2020] [Indexed: 12/15/2022]
Abstract
PURPOSE New therapies have changed the outlook for patients with multiple myeloma, but novel agents are needed for patients who are refractory or relapsed on currently approved drug classes. Novel targets other than CD38 and BCMA are needed for new immunotherapy development, as resistance to daratumumab and emerging anti-BCMA approaches appears inevitable. One potential target of interest in myeloma is ICAM1. Naked anti-ICAM1 antibodies were active in preclinical models of myeloma and safe in patients, but showed limited clinical efficacy. Here, we sought to achieve improved targeting of multiple myeloma with an anti-ICAM1 antibody-drug conjugate (ADC). EXPERIMENTAL DESIGN Our anti-ICAM1 human mAb was conjugated to an auristatin derivative, and tested against multiple myeloma cell lines in vitro, orthotopic xenografts in vivo, and patient samples ex vivo. The expression of ICAM1 was also measured by quantitative flow cytometry in patients spanning from diagnosis to the daratumumab-refractory state. RESULTS The anti-ICAM1 ADC displayed potent anti-myeloma cytotoxicity in vitro and in vivo. In addition, we have verified that ICAM1 is highly expressed on myeloma cells and shown that its expression is further accentuated by the presence of bone marrow microenvironmental factors. In primary samples, ICAM1 is differentially overexpressed on multiple myeloma cells compared with normal cells, including daratumumab-refractory patients with decreased CD38. In addition, ICAM1-ADC showed selective cytotoxicity in multiple myeloma primary samples. CONCLUSIONS We propose that anti-ICAM1 ADC should be further studied for toxicity, and if safe, tested for clinical efficacy in patients with relapsed or refractory multiple myeloma.
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Affiliation(s)
- Daniel W Sherbenou
- Department of Medicine, University of California at San Francisco, California.,Division of Hematology, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Yang Su
- Department of Anesthesia, University of California at San Francisco, California
| | | | - Blake T Aftab
- Department of Medicine, University of California at San Francisco, California.,UCSF Helen Diller Family Comprehensive Cancer Center, San Francisco, California
| | - Olivia Perez de Acha
- Division of Hematology, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Megan Murnane
- Department of Medicine, University of California at San Francisco, California
| | - Shelby C Bearrows
- Division of Hematology, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Byron C Hann
- UCSF Helen Diller Family Comprehensive Cancer Center, San Francisco, California
| | - Jeffery L Wolf
- Department of Medicine, University of California at San Francisco, California
| | - Thomas G Martin
- Department of Medicine, University of California at San Francisco, California
| | - Bin Liu
- Department of Anesthesia, University of California at San Francisco, California. .,UCSF Helen Diller Family Comprehensive Cancer Center, San Francisco, California
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6
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Bearrows SC, Bauchle CJ, Becker M, Haldeman JM, Swaminathan S, Stephens SB. Chromogranin B regulates early-stage insulin granule trafficking from the Golgi in pancreatic islet β-cells. J Cell Sci 2019; 132:jcs.231373. [PMID: 31182646 DOI: 10.1242/jcs.231373] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Accepted: 05/31/2019] [Indexed: 12/12/2022] Open
Abstract
Chromogranin B (CgB, also known as CHGB) is abundantly expressed in dense core secretory granules of multiple endocrine tissues and has been suggested to regulate granule biogenesis in some cell types, including the pancreatic islet β-cell, though the mechanisms are poorly understood. Here, we demonstrate a critical role for CgB in regulating secretory granule trafficking in the β-cell. Loss of CgB impairs glucose-stimulated insulin secretion, impedes proinsulin processing to yield increased proinsulin content, and alters the density of insulin-containing granules. Using an in situ fluorescent pulse-chase strategy to track nascent proinsulin, we show that loss of CgB impairs Golgi budding of proinsulin-containing secretory granules, resulting in a substantial delay in trafficking of nascent granules to the plasma membrane with an overall decrease in total plasma membrane-associated granules. These studies demonstrate that CgB is necessary for efficient trafficking of secretory proteins into the budding granule, which impacts the availability of insulin-containing secretory granules for exocytic release.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Shelby C Bearrows
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA 52246, USA.,Department of Internal Medicine, Division of Endocrinology and Metabolism, University of Iowa, Iowa City, IA 52246, USA
| | - Casey J Bauchle
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA 52246, USA.,Department of Internal Medicine, Division of Endocrinology and Metabolism, University of Iowa, Iowa City, IA 52246, USA
| | - McKenzie Becker
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA 52246, USA.,Department of Internal Medicine, Division of Endocrinology and Metabolism, University of Iowa, Iowa City, IA 52246, USA
| | - Jonathan M Haldeman
- Duke Molecular Physiology Institute, Duke University Medical Center, Durham, NC 27710, USA.,Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC 27710, USA
| | - Svetha Swaminathan
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA 52246, USA.,Department of Internal Medicine, Division of Endocrinology and Metabolism, University of Iowa, Iowa City, IA 52246, USA
| | - Samuel B Stephens
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA 52246, USA .,Department of Internal Medicine, Division of Endocrinology and Metabolism, University of Iowa, Iowa City, IA 52246, USA
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