1
|
Sun X, Ferguson JA, Leach BI, Stanfield RL, Dyson HJ, Wright PE. Probing the Dissociation Pathway of a Kinetically Labile Transthyretin Mutant. J Am Chem Soc 2024; 146:532-542. [PMID: 38134439 PMCID: PMC10926950 DOI: 10.1021/jacs.3c10083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2023]
Abstract
Aggregation of transthyretin (TTR) is associated with devastating amyloid diseases. Amyloidosis begins with the dissociation of the native homotetramer (a dimer of dimers) to form a monomeric intermediate that assembles into pathogenic aggregates. This process is accelerated in vitro at low pH, but the process by which TTR dissociates and reassembles at neutral pH remains poorly characterized due to the low population of intermediates. Here, we use 19F-nuclear magnetic resonance (NMR) and a highly sensitive trifluoromethyl probe to determine the relative populations of the species formed by the dissociation of a destabilized variant, A25T. The A25T mutation perturbs both the strong dimer and weak dimer-dimer interfaces. A tetramer ⇌ dimer ⇌ monomer (TDM) equilibrium model is proposed to account for concentration- and temperature-dependent population changes. Thermodynamic and kinetic parameters and activation energetics for dissociation of the native A25T tetramer, as well as a destabilized alternative tetramer (T*) with a mispacked F87 side chain, were extracted by van't Hoff and 19F-NMR line shape analysis, saturation transfer, and transition state theory. Chemical shifts for the dimer and T* species are degenerate for 19F and methyl probes close to the strong dimer interface, implicating interfacial perturbation as a common structural feature of these destabilized species. All-atom molecular dynamics simulations further suggest more frequent F87 ring flipping on the nanosecond time scale in the A25T dimer than in the native A25T tetramer. Our integrated approach offers quantitative insights into the energy landscape of the dissociation pathway of TTR at neutral pH.
Collapse
Affiliation(s)
- Xun Sun
- Department of Integrative Structural and Computational Biology and Skaggs Institute of Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
| | - James A Ferguson
- Department of Integrative Structural and Computational Biology and Skaggs Institute of Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Benjamin I Leach
- Department of Integrative Structural and Computational Biology and Skaggs Institute of Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Robyn L Stanfield
- Department of Integrative Structural and Computational Biology and Skaggs Institute of Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
| | - H Jane Dyson
- Department of Integrative Structural and Computational Biology and Skaggs Institute of Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Peter E Wright
- Department of Integrative Structural and Computational Biology and Skaggs Institute of Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
| |
Collapse
|
2
|
Ahrens ET, Helfer BM, O'Hanlon CF, Lister DR, Bykowski JL, Messer K, Leach BI, Chen J, Xu H, Daniels GA, Cohen EEW. Method for estimation of apoptotic cell fraction of cytotherapy using in vivo fluorine-19 magnetic resonance: pilot study in a patient with head and neck carcinoma receiving tumor-infiltrating lymphocytes labeled with perfluorocarbon nanoemulsion. J Immunother Cancer 2023; 11:e007015. [PMID: 37339797 PMCID: PMC10314637 DOI: 10.1136/jitc-2023-007015] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/21/2023] [Indexed: 06/22/2023] Open
Abstract
BACKGROUND Adoptive transfer of T cells is a burgeoning cancer therapeutic approach. However, the fate of the cells, once transferred, is most often unknown. We describe the first clinical experience with a non-invasive biomarker to assay the apoptotic cell fraction (ACF) after cell therapy infusion, tested in the setting of head and neck squamous cell carcinoma (HNSCC). A patient with HNSCC received autologous tumor-infiltrating lymphocytes (TILs) labeled with a perfluorocarbon (PFC) nanoemulsion cell tracer. Nanoemulsion, released from apoptotic cells, clears through the reticuloendothelial system, particularly the Kupffer cells of the liver, and fluorine-19 (19F) magnetic resonance spectroscopy (MRS) of the liver was used to non-invasively infer the ACF. METHODS Autologous TILs were isolated from a patient in their late 50s with relapsed, refractory human papillomavirus-mediated squamous cell carcinoma of the right tonsil, metastatic to the lung. A lung metastasis was resected for T cell harvest and expansion using a rapid expansion protocol. The expanded TILs were intracellularly labeled with PFC nanoemulsion tracer by coincubation in the final 24 hours of culture, followed by a wash step. At 22 days after intravenous infusion of TILs, quantitative single-voxel liver 19F MRS was performed in vivo using a 3T MRI system. From these data, we model the apparent ACF of the initial cell inoculant. RESULTS We show that it is feasible to PFC-label ~70×1010 TILs (F-TILs) in a single batch in a clinical cell processing facility, while maintaining >90% cell viability and standard flow cytometry-based release criteria for phenotype and function. Based on quantitative in vivo 19F MRS measurements in the liver, we estimate that ~30% cell equivalents of adoptively transferred F-TILs have become apoptotic by 22 days post-transfer. CONCLUSIONS Survival of the primary cell therapy product is likely to vary per patient. A non-invasive assay of ACF over time could potentially provide insight into the mechanisms of response and non-response, informing future clinical studies. This information may be useful to developers of cytotherapies and clinicians as it opens an avenue to quantify cellular product survival and engraftment.
Collapse
Affiliation(s)
- Eric T Ahrens
- Department of Radiology, University of California San Diego, La Jolla, California, USA
| | | | | | - Deanne R Lister
- Department of Radiology, University of California San Diego, La Jolla, California, USA
| | - Julie L Bykowski
- Department of Radiology, University of California San Diego, La Jolla, California, USA
| | - Karen Messer
- Division of Biostatistics, University of California San Diego, La Jolla, California, USA
| | - Benjamin I Leach
- Department of Radiology, University of California San Diego, La Jolla, California, USA
| | - Jiawen Chen
- Department of Electrical and Computer Engineering, University of California San Diego, La Jolla, California, USA
| | - Hongyan Xu
- Department of Radiology, University of California San Diego, La Jolla, California, USA
| | - Gregory A Daniels
- Department of Medicine, University of California San Diego, La Jolla, California, USA
| | - Ezra E W Cohen
- Department of Medicine, University of California San Diego, La Jolla, California, USA
| |
Collapse
|
3
|
Chapelin F, Leach BI, Chen R, Lister D, Messer K, Okada H, Ahrens ET. Assessing Oximetry Response to Chimeric Antigen Receptor T-cell Therapy against Glioma with 19F MRI in a Murine Model. Radiol Imaging Cancer 2021; 3:e200062. [PMID: 33575659 DOI: 10.1148/rycan.2021200062] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 08/10/2020] [Accepted: 09/24/2020] [Indexed: 01/24/2023]
Abstract
Purpose To assess the cell-specific, intracellular partial pressure of oxygen (Po2) dynamics of both tumor and chimeric antigen receptor (CAR) T cells in a murine immunotherapy model. Materials and Methods Human glioblastoma cells or human T cells were intracellularly labeled with perfluorocarbon nanoemulsion droplet sensors prior to in vivo injection in severe combined immunodeficient mice to measure Po2 in the two cell types in response to treatment. Two main sets of experiments were performed: (a) mice were injected in the flank with perfluorocarbon-labeled human glioblastoma cells and were then inoculated with either CAR T cells or untransduced T cells or were untreated 5 days after tumor inoculation; and (b) mice with unlabeled glioblastoma tumors were inoculated with perfluorocarbon-labeled CAR T cells or untransduced T cells 5 days after tumor inoculation. Longitudinal fluorine 19 (19F) spin-lattice relaxation time measurements of the tumor mass were used to ascertain absolute Po2 in vivo. Results were analyzed for significance using an analysis of variance, a linear mixed-effect model, and a Pearson correlation coefficient test, as appropriate. Results The intracellular tumor cell Po2 temporal dynamics exhibited delayed, transient hyperoxia at 3 days after infusion of CAR T cells, commensurate with significant tumor cell killing and CAR T-cell infiltration, as observed by bioluminescence imaging and histologic findings. Conversely, no significant changes were detected in CAR or untransduced T-cell intracellular Po2 over time in tumor using these same methods. Moreover, it was observed that the total 19F tumor cell signal quenches with treatment, consistent with rapid tissue clearance of probe from apoptotic tumor cells. Conclusion Cell-specific Po2 measurements using perfluorocarbon probes can provide insights into effector cell function and tumor response in cellular immunotherapeutic cancer models.Keywords: Animal Studies, MR-Imaging, MR-Spectroscopy, Molecular Imaging-Cancer, Molecular Imaging-Immunotherapy Supplemental material is available for this article. © RSNA, 2021See also commentary by Bulte in this issue.
Collapse
Affiliation(s)
- Fanny Chapelin
- Department of Biomedical Engineering, University of Kentucky, Lexington, Ky (F.C.); Department of Radiology (B.I.L., D.L., E.T.A.), Department of Biostatistics and Bioinformatics (R.C.), and Department of Family Medicine and Public Health (K.M.), University of California San Diego, 9500 Gilman Dr, La Jolla, CA 92093; Department of Neurologic Surgery, University of California San Francisco, San Francisco, Calif (H.O.); and Parker Institute for Cancer Immunotherapy, San Francisco, Calif (H.O.)
| | - Benjamin I Leach
- Department of Biomedical Engineering, University of Kentucky, Lexington, Ky (F.C.); Department of Radiology (B.I.L., D.L., E.T.A.), Department of Biostatistics and Bioinformatics (R.C.), and Department of Family Medicine and Public Health (K.M.), University of California San Diego, 9500 Gilman Dr, La Jolla, CA 92093; Department of Neurologic Surgery, University of California San Francisco, San Francisco, Calif (H.O.); and Parker Institute for Cancer Immunotherapy, San Francisco, Calif (H.O.)
| | - Ruifeng Chen
- Department of Biomedical Engineering, University of Kentucky, Lexington, Ky (F.C.); Department of Radiology (B.I.L., D.L., E.T.A.), Department of Biostatistics and Bioinformatics (R.C.), and Department of Family Medicine and Public Health (K.M.), University of California San Diego, 9500 Gilman Dr, La Jolla, CA 92093; Department of Neurologic Surgery, University of California San Francisco, San Francisco, Calif (H.O.); and Parker Institute for Cancer Immunotherapy, San Francisco, Calif (H.O.)
| | - Deanne Lister
- Department of Biomedical Engineering, University of Kentucky, Lexington, Ky (F.C.); Department of Radiology (B.I.L., D.L., E.T.A.), Department of Biostatistics and Bioinformatics (R.C.), and Department of Family Medicine and Public Health (K.M.), University of California San Diego, 9500 Gilman Dr, La Jolla, CA 92093; Department of Neurologic Surgery, University of California San Francisco, San Francisco, Calif (H.O.); and Parker Institute for Cancer Immunotherapy, San Francisco, Calif (H.O.)
| | - Karen Messer
- Department of Biomedical Engineering, University of Kentucky, Lexington, Ky (F.C.); Department of Radiology (B.I.L., D.L., E.T.A.), Department of Biostatistics and Bioinformatics (R.C.), and Department of Family Medicine and Public Health (K.M.), University of California San Diego, 9500 Gilman Dr, La Jolla, CA 92093; Department of Neurologic Surgery, University of California San Francisco, San Francisco, Calif (H.O.); and Parker Institute for Cancer Immunotherapy, San Francisco, Calif (H.O.)
| | - Hideho Okada
- Department of Biomedical Engineering, University of Kentucky, Lexington, Ky (F.C.); Department of Radiology (B.I.L., D.L., E.T.A.), Department of Biostatistics and Bioinformatics (R.C.), and Department of Family Medicine and Public Health (K.M.), University of California San Diego, 9500 Gilman Dr, La Jolla, CA 92093; Department of Neurologic Surgery, University of California San Francisco, San Francisco, Calif (H.O.); and Parker Institute for Cancer Immunotherapy, San Francisco, Calif (H.O.)
| | - Eric T Ahrens
- Department of Biomedical Engineering, University of Kentucky, Lexington, Ky (F.C.); Department of Radiology (B.I.L., D.L., E.T.A.), Department of Biostatistics and Bioinformatics (R.C.), and Department of Family Medicine and Public Health (K.M.), University of California San Diego, 9500 Gilman Dr, La Jolla, CA 92093; Department of Neurologic Surgery, University of California San Francisco, San Francisco, Calif (H.O.); and Parker Institute for Cancer Immunotherapy, San Francisco, Calif (H.O.)
| |
Collapse
|
4
|
Wang C, Leach BI, Lister D, Adams SR, Xu H, Hoh C, McConville P, Zhang J, Messer K, Ahrens ET. Metallofluorocarbon Nanoemulsion for Inflammatory Macrophage Detection via PET and MRI. J Nucl Med 2020; 62:1146-1153. [DOI: 10.2967/jnumed.120.255273] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Accepted: 11/12/2020] [Indexed: 12/14/2022] Open
|
5
|
Schmidt CR, Achille NJ, Kuntimaddi A, Boulton AM, Leach BI, Zhang S, Zeleznik-Le NJ, Bushweller JH. BCOR Binding to MLL-AF9 Is Essential for Leukemia via Altered EYA1, SIX, and MYC Activity. Blood Cancer Discov 2020; 1:162-177. [PMID: 32954361 DOI: 10.1158/2643-3230.bcd-20-0036] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
MLL is a target of chromosomal translocations in acute leukemias with poor prognosis. The common MLL fusion partner AF9 (MLLT3) can directly bind to AF4, DOT1L, BCOR, and CBX8. To delineate the relevance of BCOR and CBX8 binding to MLL-AF9 for leukemogenesis, here we determine protein structures of AF9 complexes with CBX8 and BCOR, and show that binding of all four partners to AF9 is mutually exclusive. Using the structural analyses, we identify point mutations that selectively disrupt AF9 interactions with BCOR and CBX8. In bone marrow stem/progenitor cells expressing point mutant CBX8 or point mutant MLL-AF9, we show that disruption of direct CBX8/MLL-AF9 binding does not impact in vitro cell proliferation, whereas loss of direct BCOR/MLL-AF9 binding causes partial differentiation and increased proliferation. Strikingly, loss of MLL-AF9/BCOR binding abrogated its leukemogenic potential in a mouse model. The MLL-AF9 mutant deficient for BCOR binding reduces the expression of the EYA1 phosphatase and the protein level of c-Myc. Reduction in BCOR binding to MLL-AF9 alters a MYC-driven gene expression program, as well as altering expression of SIX-regulated genes, likely contributing to the observed reduction in the leukemia-initiating cell population.
Collapse
Affiliation(s)
- Charles R Schmidt
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, Virginia
| | - Nicholas J Achille
- Department of Cancer Biology, Loyola University Chicago, Maywood, Illinois
| | - Aravinda Kuntimaddi
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, Virginia
| | - Adam M Boulton
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, Virginia
| | - Benjamin I Leach
- Department of Cancer Biology, Loyola University Chicago, Maywood, Illinois
| | - Shubin Zhang
- Department of Cancer Biology, Loyola University Chicago, Maywood, Illinois
| | - Nancy J Zeleznik-Le
- Department of Cancer Biology, Loyola University Chicago, Maywood, Illinois.
- Department of Medicine, Loyola University Chicago, Maywood, Illinois
| | - John H Bushweller
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, Virginia.
| |
Collapse
|
6
|
Foronda M, Tarumoto Y, Schatoff EM, Leach BI, Diaz BJ, Zimmerman J, Goswami S, Shusterman M, Vakoc CR, Dow LE. Tankyrase inhibition sensitizes cells to CDK4 blockade. PLoS One 2019; 14:e0226645. [PMID: 31891587 PMCID: PMC6938305 DOI: 10.1371/journal.pone.0226645] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [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: 06/26/2019] [Accepted: 11/30/2019] [Indexed: 12/17/2022] Open
Abstract
Tankyrase (TNKS) 1/2 are positive regulators of WNT signaling by controlling the activity of the ß-catenin destruction complex. TNKS inhibitors provide an opportunity to suppress hyperactive WNT signaling in tumors, however, they have shown limited anti-proliferative activity as a monotherapy in human cancer cell lines. Here we perform a kinome-focused CRISPR screen to identify potential effective drug combinations with TNKS inhibition. We show that the loss of CDK4, but not CDK6, synergizes with TNKS1/2 blockade to drive G1 cell cycle arrest and senescence. Through precise modelling of cancer-associated mutations using cytidine base editors, we show that this therapeutic approach is absolutely dependent on suppression of canonical WNT signaling by TNKS inhibitors and is effective in cells from multiple epithelial cancer types. Together, our results suggest that combined WNT and CDK4 inhibition might provide a potential therapeutic strategy for difficult-to-treat epithelial tumors.
Collapse
Affiliation(s)
- Miguel Foronda
- Sandra and Edward Meyer Cancer Center, Weill Cornell Medicine, New York, NY, United States of America
| | - Yusuke Tarumoto
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, United States of America
| | - Emma M. Schatoff
- Sandra and Edward Meyer Cancer Center, Weill Cornell Medicine, New York, NY, United States of America
- Tri-Institutional MD-PhD program, Weill Cornell Medicine, New York, NY, United States of America
| | - Benjamin I. Leach
- Sandra and Edward Meyer Cancer Center, Weill Cornell Medicine, New York, NY, United States of America
| | - Bianca J. Diaz
- Sandra and Edward Meyer Cancer Center, Weill Cornell Medicine, New York, NY, United States of America
| | - Jill Zimmerman
- Sandra and Edward Meyer Cancer Center, Weill Cornell Medicine, New York, NY, United States of America
| | - Sukanya Goswami
- Sandra and Edward Meyer Cancer Center, Weill Cornell Medicine, New York, NY, United States of America
| | - Michael Shusterman
- Sandra and Edward Meyer Cancer Center, Weill Cornell Medicine, New York, NY, United States of America
| | | | - Lukas E. Dow
- Sandra and Edward Meyer Cancer Center, Weill Cornell Medicine, New York, NY, United States of America
- Department of Medicine, Weill Cornell Medicine, New York, NY, United States of America
- Department of Biochemistry, Weill Cornell Medicine, New York, NY, United States of America
- * E-mail:
| |
Collapse
|
7
|
Schatoff EM, Goswami S, Zafra MP, Foronda M, Shusterman M, Leach BI, Katti A, Diaz BJ, Dow LE. Distinct Colorectal Cancer-Associated APC Mutations Dictate Response to Tankyrase Inhibition. Cancer Discov 2019; 9:1358-1371. [PMID: 31337618 DOI: 10.1158/2159-8290.cd-19-0289] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Revised: 07/10/2019] [Accepted: 07/18/2019] [Indexed: 12/17/2022]
Abstract
The majority of colorectal cancers show hyperactivated WNT signaling due to inactivating mutations in the adenomatous polyposis coli (APC) tumor suppressor. Genetically restoring APC suppresses WNT and induces rapid and sustained tumor regression, implying that reengaging this endogenous tumor-suppressive mechanism may be an effective therapeutic strategy. Here, using new animal models, human cell lines, and ex vivo organoid cultures, we show that tankyrase (TNKS) inhibition can control WNT hyperactivation and provide long-term tumor control in vivo, but that effective responses are critically dependent on how APC is disrupted. Mutant APC proteins truncated within the mutation cluster region physically engage the destruction complex and suppress the WNT transcriptional program, while APC variants with early truncations (e.g., Apc Min) show limited interaction with AXIN1 and β-catenin, and do not respond to TNKS blockade. Together, this work shows that TNKS inhibition, like APC restoration, can reestablish endogenous control of WNT/β-catenin signaling, but that APC genotype is a crucial determinant of this response. SIGNIFICANCE: This study reveals how subtle changes to the mutations in a critical colorectal tumor suppressor, APC, influence the cellular response to a targeted therapy. It underscores how investigating the specific genetic alterations that occur in human cancer can identify important biological mechanisms of drug response and resistance.This article is highlighted in the In This Issue feature, p. 1325.
Collapse
Affiliation(s)
- Emma M Schatoff
- Sandra and Edward Meyer Cancer Center, Department of Medicine, Weill Cornell Medicine, New York, New York.,Weill Cornell/Rockefeller/Sloan Kettering Tri-I MD-PhD program, New York, New York.,Weill Cornell Graduate School of Medical Sciences, Weill Cornell Medicine, New York, New York
| | - Sukanya Goswami
- Sandra and Edward Meyer Cancer Center, Department of Medicine, Weill Cornell Medicine, New York, New York
| | - Maria Paz Zafra
- Sandra and Edward Meyer Cancer Center, Department of Medicine, Weill Cornell Medicine, New York, New York
| | - Miguel Foronda
- Sandra and Edward Meyer Cancer Center, Department of Medicine, Weill Cornell Medicine, New York, New York
| | - Michael Shusterman
- Sandra and Edward Meyer Cancer Center, Department of Medicine, Weill Cornell Medicine, New York, New York
| | - Benjamin I Leach
- Sandra and Edward Meyer Cancer Center, Department of Medicine, Weill Cornell Medicine, New York, New York
| | - Alyna Katti
- Sandra and Edward Meyer Cancer Center, Department of Medicine, Weill Cornell Medicine, New York, New York.,Weill Cornell Graduate School of Medical Sciences, Weill Cornell Medicine, New York, New York
| | - Bianca J Diaz
- Sandra and Edward Meyer Cancer Center, Department of Medicine, Weill Cornell Medicine, New York, New York.,Weill Cornell Graduate School of Medical Sciences, Weill Cornell Medicine, New York, New York
| | - Lukas E Dow
- Sandra and Edward Meyer Cancer Center, Department of Medicine, Weill Cornell Medicine, New York, New York. .,Weill Cornell Graduate School of Medical Sciences, Weill Cornell Medicine, New York, New York.,Department of Biochemistry, Weill Cornell Medicine, New York, New York
| |
Collapse
|
8
|
Abstract
Inherited mutations of transthyretin (TTR) destabilize its structure, leading to aggregation and familial amyloid disease. Although numerous crystal structures of wild-type (WT) and mutant TTRs have been determined, they have failed to yield a comprehensive structural explanation for destabilization by pathogenic mutations. To identify structural and dynamic variations that are not readily observed in the crystal structures, we used NMR to study WT TTR and three kinetically and/or thermodynamically destabilized pathogenic variants (V30M, L55P, and V122I). Sequence-corrected chemical shifts reveal important structural differences between WT and mutant TTR. The L55P mutation linked to aggressive early onset cardiomyopathy and polyneuropathy induces substantial structural perturbations in both the DAGH and CBEF β-sheets, whereas the V30M polyneuropathy-linked substitution perturbs primarily the CBEF sheet. In both variants, the structural perturbations propagate across the entire width of the β-sheets from the site of mutation. Structural changes caused by the V122I cardiomyopathy-associated mutation are restricted to the immediate vicinity of the mutation site, directly perturbing the subunit interfaces. NMR relaxation dispersion measurements show that WT TTR and the three pathogenic variants undergo millisecond time scale conformational fluctuations to populate a common excited state with an altered structure in the subunit interfaces. The excited state is most highly populated in L55P. The combined application of chemical shift analysis and relaxation dispersion to these pathogenic variants reveals differences in ground state structure and in the population of a transient excited state that potentially facilitates tetramer dissociation, providing new insights into the molecular mechanism by which mutations promote TTR amyloidosis.
Collapse
Affiliation(s)
- Benjamin I. Leach
- Department of Integrative Structural and Computational Biology and Skaggs Institute of Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California, 92037
| | - Xin Zhang
- Department of Chemistry, Pennsylvania State University, University Park, Pennsylvania16802
| | - Jeffery W. Kelly
- Department of Chemistry and Skaggs Institute of Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California, 92037
| | - H. Jane Dyson
- Department of Integrative Structural and Computational Biology and Skaggs Institute of Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California, 92037
| | - Peter E. Wright
- Department of Integrative Structural and Computational Biology and Skaggs Institute of Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California, 92037
| |
Collapse
|
9
|
Schatoff EM, Leach BI, Foronda M, Zafra MP, Goswami S, Dow LE. Abstract LB-089: Targeting WNT signaling in vivovia Tankyrase inhibition. Cancer Res 2018. [DOI: 10.1158/1538-7445.am2018-lb-089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
Colorectal cancer (CRC) is the second leading cause of cancer-related death in the United States. Approximately 95% of CRCs show hyperactive WNT signaling, yet there are no targeted therapies that effectively suppress the WNT pathway. The majority (~80%) of these tumors harbor a mutation in APC, a scaffold component of the ‘destruction complex', which is a critical negative regulator of WNT. Using genetically defined mouse models of CRC, we recently showed that restoring Apc function can induce WNT suppression, and rapid and sustained disease regression. While there is no way to restore normal APC protein in human CRCs, it may be possible to restore the function of the APC-associated destruction complex by inhibiting Tankyrase (TNKS) enzymes. Tankyrase inhibitors have been shown to stabilize AXIN, prevent degradation of the destruction complex, and decrease levels of WNT signaling. While in vitro studies have shown promise, it is unclear whether TNKS inhibition could provide a therapeutic benefit in vivo. Some published work reports significant anti-tumor activity, while others suggest overt dose-limiting toxicity. Thus, while TNKS inhibition holds significant potential, it is not clear whether TNKS enzymes are a viable target for CRC therapy. To circumvent the limitations of drug delivery, potency, and specificity, we generated mice with inducible, fluorescent reporter-linked shRNAs targeting Tnks and its redundant family member Tnks2. Here we show that potent, simultaneous shRNA-mediated knockdown of both genes is sufficient to stabilize Axin in vivo, similar to treatment with a pan-TNKS inhibitor, XAV939. We show that Tnks1/2 knockdown stabilizes Axin, suppresses WNT signaling, and blocks hyperproliferation driven by Apc loss. In contrast to current studies using small molecule TNKS inhibitors, our work suggests that there is a viable therapeutic window of TNKS1/2 inhibition in vivo, and that this strategy enables control of hyperactive WNT signaling in CRC and other WNT-associated cancers.
Citation Format: Emma M. Schatoff, Benjamin I. Leach, Miguel Foronda, Maria Paz Zafra, Sukanya Goswami, Lukas E. Dow. Targeting WNT signaling in vivovia Tankyrase inhibition [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr LB-089.
Collapse
|
10
|
Schatoff EM, Leach BI, Foronda M, Zafra MP, Dow L. Abstract B32: Targeting WNT signaling in vivo via Tankyrase inhibition. Cancer Res 2018. [DOI: 10.1158/1538-7445.mousemodels17-b32] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
Colorectal cancer (CRC) is the second leading cause of cancer-related death in the United States. Approximately 95% of CRCs show hyperactive WNT signaling, yet there are no targeted therapies that effectively suppress the WNT pathway. The majority (~80%) of these tumors harbor a mutation in APC, a scaffold component of the “destruction complex,” which is a critical negative regulator of WNT.
Using genetically defined mouse models of CRC, we recently showed that restoring Apc function can induce WNT suppression and rapid and sustained disease regression. While there is no way to restore normal APC protein in human CRCs, it may be possible to restore the function of the APC-associated destruction complex by inhibiting Tankyrase (TNKS) enzymes. Tankyrase inhibitors have been shown to stabilize AXIN, prevent degradation of the destruction complex, and decrease levels of WNT signaling. While in vitro studies have shown promise, it is unclear whether TNKS inhibition could provide a therapeutic benefit in vivo. Some published work reports significant antitumor activity, while others suggest overt dose-limiting toxicity. Thus, while TNKS inhibition holds significant potential, it is not clear whether TNKS enzymes are a viable target for CRC therapy.
To circumvent the limitations of drug delivery, potency, and specificity, we generated mice with inducible, fluorescent reporter-linked shRNAs targeting Tnks and its redundant family member Tnks2. Here we show that potent, simultaneous shRNA-mediated knockdown of both genes is sufficient to stabilize Axin in vivo, similar to treatment with a pan-TNKS inhibitor, XAV939. We show that Tnks1/2 knockdown stabilizes Axin and suppresses WNT signaling, but surprisingly, does not disrupt intestinal architecture. Importantly, Tnks1/2 silencing blocks hyperproliferation and tumor development in mice following Apc disruption. In contrast to current studies using small-molecule TNKS inhibitors, our work suggests that there is a viable therapeutic window of TNKS1/2 inhibition in vivo, and that this strategy enables control of hyperactive WNT signaling in CRC and other WNT-associated cancers.
Citation Format: Emma M. Schatoff, Benjamin I. Leach, Miguel Foronda, Maria Paz Zafra, Lukas Dow. Targeting WNT signaling in vivo via Tankyrase inhibition [abstract]. In: Proceedings of the AACR Special Conference: Advances in Modeling Cancer in Mice: Technology, Biology, and Beyond; 2017 Sep 24-27; Orlando, Florida. Philadelphia (PA): AACR; Cancer Res 2018;78(10 Suppl):Abstract nr B32.
Collapse
Affiliation(s)
| | | | | | | | - Lukas Dow
- Weill Cornell Medicine, New York, NY
| |
Collapse
|
11
|
Abstract
The WNT signaling pathway is a critical mediator of tissue homeostasis and repair, and frequently co-opted during tumor development. Almost all colorectal cancers (CRC) demonstrate hyperactivation of the WNT pathway, which in many cases is believed to be the initiating and driving event. In this short review, we provide a focused overview of recent developments in our understanding of the WNT pathway in CRC, describe new research tools that are enabling a deeper understanding of WNT biology, and outline ongoing efforts to target this pathway therapeutically.
Collapse
Affiliation(s)
- Emma M Schatoff
- Sandra and Edward Meyer Cancer Center, Weill Cornell Medicine, New York, 10021.,Weill Cornell/Rockefeller/Sloan Kettering Tri-I MD-PhD program, New York, 10065
| | - Benjamin I Leach
- Sandra and Edward Meyer Cancer Center, Weill Cornell Medicine, New York, 10021.,New York Presbyterian Hospital, New York, 10021
| | - Lukas E Dow
- Sandra and Edward Meyer Cancer Center, Weill Cornell Medicine, New York, 10021.,Department of Medicine, Weill Cornell Medicine, New York, 10021.,Department of Biochemistry, Weill Cornell Medicine, New York, 10021
| |
Collapse
|
12
|
Fedashchin A, Cernota WH, Gonzalez MC, Leach BI, Kwan N, Wesley RK, Weber JM. Random transposon mutagenesis of the Saccharopolyspora erythraea genome reveals additional genes influencing erythromycin biosynthesis. FEMS Microbiol Lett 2015; 362:fnv180. [PMID: 26468041 DOI: 10.1093/femsle/fnv180] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/25/2015] [Indexed: 12/25/2022] Open
Abstract
A single cycle of strain improvement was performed in Saccharopolyspora erythraea mutB and 15 genotypes influencing erythromycin production were found. Genotypes generated by transposon mutagenesis appeared in the screen at a frequency of ~3%. Mutations affecting central metabolism and regulatory genes were found, as well as hydrolases, peptidases, glycosyl transferases and unknown genes. Only one mutant retained high erythromycin production when scaled-up from micro-agar plug fermentations to shake flasks. This mutant had a knockout of the cwh1 gene (SACE_1598), encoding a cell-wall-associated hydrolase. The cwh1 knockout produced visible growth and morphological defects on solid medium. This study demonstrated that random transposon mutagenesis uncovers strain improvement-related genes potentially useful for strain engineering.
Collapse
Affiliation(s)
- Andrij Fedashchin
- Fermalogic, Research and Development, 4222 N. Ravenswood Avenue, Chicago, IL 60613, USA
| | - William H Cernota
- Fermalogic, Research and Development, 4222 N. Ravenswood Avenue, Chicago, IL 60613, USA
| | - Melissa C Gonzalez
- Fermalogic, Research and Development, 4222 N. Ravenswood Avenue, Chicago, IL 60613, USA
| | - Benjamin I Leach
- Fermalogic, Research and Development, 4222 N. Ravenswood Avenue, Chicago, IL 60613, USA
| | - Noelle Kwan
- Fermalogic, Research and Development, 4222 N. Ravenswood Avenue, Chicago, IL 60613, USA
| | - Roy K Wesley
- Fermalogic, Research and Development, 4222 N. Ravenswood Avenue, Chicago, IL 60613, USA
| | - J Mark Weber
- Fermalogic, Research and Development, 4222 N. Ravenswood Avenue, Chicago, IL 60613, USA
| |
Collapse
|
13
|
Lokken AA, Achille NJ, Chang MJ, Lin JJ, Kuntimaddi A, Leach BI, Malik B, Nesbit JB, Zhang S, Bushweller JH, Zeleznik-Le NJ, Hemenway CS. Importance of a specific amino acid pairing for murine MLL leukemias driven by MLLT1/3 or AFF1/4. Leuk Res 2014; 38:1309-15. [PMID: 25282333 DOI: 10.1016/j.leukres.2014.08.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [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: 03/28/2014] [Revised: 08/06/2014] [Accepted: 08/16/2014] [Indexed: 11/26/2022]
Abstract
Acute leukemias caused by translocations of the MLL gene at chromosome 11 band q23 (11q23) are characterized by a unique gene expression profile. More recently, data from several laboratories indicate that the most commonly encountered MLL fusion proteins, MLLT1, MLLT3, and AFF1 are found within a molecular complex that facilitates the elongation phase of mRNA transcription. Mutational analyses suggest that interaction between the MLLT1/3 proteins and AFF family proteins are required for experimental transformation of hematopoietic progenitor cells (HPCs). Here, we define a specific pairing of two amino acids that creates a salt bridge between MLLT1/3 and AFF proteins that is critically important for MLL-mediated transformation of HPCs. Our findings, coupled with the newly defined structure of MLLT3 in complex with AFF1, should facilitate the development of small molecules that block this amino acid interaction and interfere with the activity of the most common MLL oncoproteins.
Collapse
Affiliation(s)
- Alyson A Lokken
- The Molecular Biology Program, Loyola University Chicago Health Sciences Division, Maywood, IL 60153, United States
| | - Nicholas J Achille
- Oncology Research Institute, Loyola University Chicago Health Sciences Division, Maywood, IL 60153, United States
| | - Ming-Jin Chang
- Department of Biochemistry, Tulane University School of Medicine, New Orleans, LA 70112, United States
| | - Jeffrey J Lin
- Department of Biochemistry, Tulane University School of Medicine, New Orleans, LA 70112, United States
| | - Aravinda Kuntimaddi
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA 22908, United States
| | - Benjamin I Leach
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA 22908, United States
| | - Bhavna Malik
- The Molecular Biology Program, Loyola University Chicago Health Sciences Division, Maywood, IL 60153, United States
| | - Jacqueline B Nesbit
- Department of Biochemistry, Tulane University School of Medicine, New Orleans, LA 70112, United States
| | - Shubin Zhang
- Oncology Research Institute, Loyola University Chicago Health Sciences Division, Maywood, IL 60153, United States
| | - John H Bushweller
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA 22908, United States
| | - Nancy J Zeleznik-Le
- Oncology Research Institute, Loyola University Chicago Health Sciences Division, Maywood, IL 60153, United States; Department of Medicine, Loyola University Chicago Health Sciences Division, Maywood, IL 60153, United States.
| | - Charles S Hemenway
- Oncology Research Institute, Loyola University Chicago Health Sciences Division, Maywood, IL 60153, United States; Department of Pediatrics, Loyola University Chicago Health Sciences Division, Maywood, IL 60153, United States.
| |
Collapse
|
14
|
Leach BI, Kuntimaddi A, Schmidt CR, Cierpicki T, Johnson SA, Bushweller JH. Leukemia fusion target AF9 is an intrinsically disordered transcriptional regulator that recruits multiple partners via coupled folding and binding. Structure 2012; 21:176-183. [PMID: 23260655 DOI: 10.1016/j.str.2012.11.011] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2012] [Revised: 10/19/2012] [Accepted: 11/13/2012] [Indexed: 01/31/2023]
Abstract
Mixed lineage leukemia (MLL) fusion proteins cause oncogenic transformation of hematopoietic cells by constitutive recruitment of elongation factors to HOX promoters, resulting in overexpression of target genes. The structural basis of transactivation by MLL fusion partners remains undetermined. We show that the ANC1 homology domain (AHD) of AF9, one of the most common MLL translocation partners, is intrinsically disordered and recruits multiple transcription factors through coupled folding and binding. We determined the structure of the AF9 AHD in complex with the elongation factor AF4 and show that aliphatic residues, which are conserved in each of the AF9 binding partners, form an integral part of the hydrophobic core of the complex. Nuclear magnetic resonance relaxation measurements show that AF9 retains significant dynamic behavior which may facilitate exchange between disordered partners. We propose that AF9 functions as a signaling hub that regulates transcription through dynamic recruitment of cofactors in normal hematopoiesis and in acute leukemia.
Collapse
Affiliation(s)
- Benjamin I Leach
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA 22908, USA
| | - Aravinda Kuntimaddi
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA 22908, USA
| | - Charles R Schmidt
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA 22908, USA
| | - Tomasz Cierpicki
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA 22908, USA
| | - Stephanie A Johnson
- Department of Chemistry, University of Virginia, Charlottesville, VA 22904, USA
| | - John H Bushweller
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA 22908, USA; Department of Chemistry, University of Virginia, Charlottesville, VA 22904, USA.
| |
Collapse
|
15
|
Weber JM, Cernota WH, Gonzalez MC, Leach BI, Reeves AR, Wesley RK. An erythromycin process improvement using the diethyl methylmalonate-responsive (Dmr) phenotype of the Saccharopolyspora erythraea mutB strain. Appl Microbiol Biotechnol 2011; 93:1575-83. [PMID: 22048617 DOI: 10.1007/s00253-011-3650-3] [Citation(s) in RCA: 10] [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: 08/23/2011] [Revised: 09/27/2011] [Accepted: 10/17/2011] [Indexed: 11/24/2022]
Abstract
The Saccharopolyspora erythraea mutB knockout strain, FL2281, having a block in the methylmalonyl-CoA mutase reaction, was found to carry a diethyl methylmalonate-responsive (Dmr) phenotype in an oil-based fermentation medium. The Dmr phenotype confers the ability to increase erythromycin A (erythromycin) production from 250-300% when the oil-based medium is supplemented with 15 mM levels of this solvent. Lower concentrations of the solvent stimulated proportionately less erythromycin production, while higher concentrations had no additional benefit. Although the mutB strain is phenotypically a low-level erythromycin producer, diethyl methylmalonate supplementation allowed it to produce up to 30% more erythromycin than the wild-type (control) strain-a strain that does not show the Dmr phenotype. The Dmr phenotype represents a new class of strain improvement phenotype. A theory to explain the biochemical mechanism for the Dmr phenotype is proposed. Other phenotypes found to be associated with the mutB knockout were a growth defect and hyper-pigmentation, both of which were restored to normal by exposure to diethyl methylmalonate. Furthermore, mutB fermentations did not significantly metabolize soybean oil in the presence of diethyl methylmalonate. Finally, a novel method is proposed for the isolation of additional mutants with the Dmr phenotype.
Collapse
Affiliation(s)
- J Mark Weber
- Fermalogic, Inc, 920 North Franklin Street, Chicago, IL 60610, USA.
| | | | | | | | | | | |
Collapse
|
16
|
Reeves AR, Brikun IA, Cernota WH, Leach BI, Gonzalez MC, Weber JM. Engineering of the methylmalonyl-CoA metabolite node of Saccharopolyspora erythraea for increased erythromycin production. Metab Eng 2007; 9:293-303. [PMID: 17482861 PMCID: PMC2722834 DOI: 10.1016/j.ymben.2007.02.001] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2006] [Revised: 01/23/2007] [Accepted: 02/27/2007] [Indexed: 10/23/2022]
Abstract
Engineering of the methylmalonyl-CoA (mmCoA) metabolite node of the Saccharopolyspora erythraea wild-type strain through duplication of the mmCoA mutase (MCM) operon led to a 50% increase in erythromycin production in a high-performance oil-based fermentation medium. The MCM operon was carried on a 6.8kb DNA fragment in a plasmid which was inserted by homologous recombination into the S. erythraea chromosome. The fragment contained one uncharacterized gene, ORF1; three MCM related genes, mutA, mutB, meaB; and one gntR-family regulatory gene, mutR. Additional strains were constructed containing partial duplications of the MCM operon, as well as a knockout of ORF1. None of these strains showed any significant alteration in their erythromycin production profile. The combined results showed that increased erythromycin production only occurred in a strain containing a duplication of the entire MCM operon including mutR and a predicted stem-loop structure overlapping the 3' terminus of the mutR coding sequence.
Collapse
Affiliation(s)
- Andrew R Reeves
- Fermalogic Inc. Research and Development, 2201 West Campbell Park Drive, Chicago, IL 60612, US
| | | | | | | | | | | |
Collapse
|
17
|
Adam PJ, Terrett JA, Steers G, Stockwin L, Loader JA, Fletcher GC, Lu LS, Leach BI, Mason S, Stamps AC, Boyd RS, Pezzella F, Gatter KC, Harris AL. CD70 (TNFSF7) is expressed at high prevalence in renal cell carcinomas and is rapidly internalised on antibody binding. Br J Cancer 2006; 95:298-306. [PMID: 16892042 PMCID: PMC2360640 DOI: 10.1038/sj.bjc.6603222] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
In order to identify potential markers of renal cancer, the plasma membrane protein content of renal cell carcinoma (RCC)-derived cell lines was annotated using a proteomics process. One unusual protein identified at high levels in A498 and 786-O cells was CD70 (TNFSF7), a type II transmembrane receptor normally expressed on a subset of B, T and NK cells, where it plays a costimulatory role in immune cell activation. Immunohistochemical analysis of CD70 expression in multiple carcinoma types demonstrated strong CD70 staining in RCC tissues. Metastatic tissues from eight of 11 patients with clear cell RCC were positive for CD70 expression. Immunocytochemical analysis demonstrated that binding of an anti-CD70 antibody to CD70 endogenously expressed on the surface of A498 and 786-O cell lines resulted in the rapid internalisation of the antibody-receptor complex. Coincubation of the internalising anti-CD70 antibody with a saporin-conjugated secondary antibody before addition to A498 cells resulted in 50% cell killing. These data indicate that CD70 represents a potential target antigen for toxin-conjugated therapeutic antibody treatment of RCC.
Collapse
Affiliation(s)
- P J Adam
- Celltech Antibody Centre of Excellence, 216 Bath Road, Slough, Berkshire SL1 4EN, UK
| | - J A Terrett
- Medarex Inc., 521 Cottonwood Drive, Milpitas, CA 94022, USA
| | - G Steers
- Cancer Research UK Molecular Oncology Laboratories, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, Oxford OX3 9DS, UK
| | - L Stockwin
- Celltech Antibody Centre of Excellence, 216 Bath Road, Slough, Berkshire SL1 4EN, UK
| | - J A Loader
- Celltech Antibody Centre of Excellence, 216 Bath Road, Slough, Berkshire SL1 4EN, UK
| | - G C Fletcher
- Celltech Antibody Centre of Excellence, 216 Bath Road, Slough, Berkshire SL1 4EN, UK
| | - L-S Lu
- Medarex Inc., 521 Cottonwood Drive, Milpitas, CA 94022, USA
| | - B I Leach
- Celltech Antibody Centre of Excellence, 216 Bath Road, Slough, Berkshire SL1 4EN, UK
| | - S Mason
- Celltech Antibody Centre of Excellence, 216 Bath Road, Slough, Berkshire SL1 4EN, UK
| | - A C Stamps
- Celltech Antibody Centre of Excellence, 216 Bath Road, Slough, Berkshire SL1 4EN, UK
- E-mail:
| | - R S Boyd
- MRC Toxicology Unit, Hodgkin Building, University of Leicester, P.O. Box 138, Lancaster Rd, Leicester LE1 9HN, UK
| | - F Pezzella
- Cancer Research UK Molecular Oncology Laboratories, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, Oxford OX3 9DS, UK
| | - K C Gatter
- Cancer Research UK Molecular Oncology Laboratories, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, Oxford OX3 9DS, UK
| | - A L Harris
- Cancer Research UK Molecular Oncology Laboratories, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, Oxford OX3 9DS, UK
| |
Collapse
|
18
|
Reeves AR, Brikun IA, Cernota WH, Leach BI, Gonzalez MC, Weber JM. Effects of methylmalonyl-CoA mutase gene knockouts on erythromycin production in carbohydrate-based and oil-based fermentations of Saccharopolyspora erythraea. J Ind Microbiol Biotechnol 2006; 33:600-9. [PMID: 16491356 DOI: 10.1007/s10295-006-0094-3] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2005] [Accepted: 02/01/2006] [Indexed: 10/25/2022]
Abstract
In carbohydrate-based fermentations of Saccharopolyspora erythraea, a polar knockout of the methylmalonyl-CoA mutase (MCM) gene, mutB, improved erythromycin production an average of 126% (within the range of 102-153% for a 0.95 confidence interval). In oil-based fermentations, where erythromycin production by the wild-type strain averages 184% higher (141-236%, 0.95 CI) than in carbohydrate-based fermentations, the same polar knockout in mutB surprisingly reduced erythromycin production by 66% (53-76%, 0.95 CI). A metabolic model is proposed where in carbohydrate-based fermentations MCM acts as a drain on the methylmalonyl-CoA metabolite pool, and in oil-based fermentations, MCM acts in the reverse direction to fill the methylmalonyl-CoA pool. Therefore, the model explains, in part, how the well-known oil-based process improvement for erythromycin production operates at the biochemical level; furthermore, it illustrates how the mutB erythromycin strain improvement mutation operates at the genetic level in carbohydrate-based fermentations.
Collapse
Affiliation(s)
- Andrew R Reeves
- Fermalogic Inc., 2201 West Campbell Park Drive, Chicago, IL 60612, USA
| | | | | | | | | | | |
Collapse
|