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Hou X, Wang F, Meng X, Li D, Ding J, Chen Y, Wang Z, Zhu H, Yang Z. Construction of a 124I-Labeled Specific Antibody for the Noninvasive Detection of Mesothelin-Overexpressing Tumors. Mol Pharm 2022; 19:3623-3631. [PMID: 35904514 DOI: 10.1021/acs.molpharmaceut.2c00342] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Mesothelin (MSLN) is a molecular biomarker of many types of solid tumors, such as mesothelioma, pancreatic cancer, and colon cancer. Owing to the significant difference in expression between cancer cells and normal cells, mesothelin has been widely used as a key target in cancer immunotherapy. In this study, we used iodine isotope (nat/124/125I)-labeled mesothelin antibodies to noninvasively detect MSLN expression in mice with LS174T colon cancer. The 124I-labeled MSLN antibody showed a high radiochemical purity (RCP, >99%) and specific activity (20.8-67.8 GBq/μmol) after purification and was stable in 5% HSA and PBS (>95% RCP at 8 days). Western blot analysis indicated that the LS174T cells showed a higher MSLN protein level than the HepG2 cells. The half maximal effective concentration (EC50) values of the MSLN antibody and natI-anti-MSLN were 34.77 ± 3.72 ng/mL and 32.60 ± 2.52 ng/mL (P = 0.63), respectively. The dissociation constant of 124I-anti-MSLN binding to MSLN protein was 16.0 nM. The radiotracer showed a significantly higher uptake in LS174T cells than in HepG2 tumor cells (1.56 ± 0.09 vs 0.81 ± 0.03, P = 0.0016) 2 days postinjection. The LS174T mouse models showed extremely low organ uptake and high tumor uptake 96 h after the injection of 124I-anti-MSLN, and the T/M values were much higher than those of the other imaging groups (10.56 ± 1.20 for 124I-anti-MSLN in LS174T mice vs 3.27 ± 0.20 for 124I-anti-MSLN in HepG2 mice vs 3.53 ± 0.2 for 124I-IgG in LS174T mice). The immunochemical histology results showed that LS174T tumors were strongly positive (+++) for MSLN, while those in the HepG2 group showed slight expression (+). The dosimetry estimation study showed that the effective dose of 124I-anti-MSLN was 0.185 mSv/MBq, which is within the range of acceptable doses for further nuclear medicine translational research. Taken together, these results suggest that this radiotracer has the potential for detecting mesothelin-overexpressing tumors.
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Affiliation(s)
- Xingguo Hou
- Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), NMPA Key Laboratory for Research and Evaluation of Radiopharmaceuticals (National Medical Products Administration), Department of Nuclear Medicine, Peking University Cancer Hospital and Institute, Beijing 100142, China.,Institute of Biomedical Engineering, Peking University Shenzhen Graduate School, Shenzhen, Guangdong 518055, China
| | - Feng Wang
- Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), NMPA Key Laboratory for Research and Evaluation of Radiopharmaceuticals (National Medical Products Administration), Department of Nuclear Medicine, Peking University Cancer Hospital and Institute, Beijing 100142, China
| | - Xiangxi Meng
- Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), NMPA Key Laboratory for Research and Evaluation of Radiopharmaceuticals (National Medical Products Administration), Department of Nuclear Medicine, Peking University Cancer Hospital and Institute, Beijing 100142, China
| | - Dan Li
- Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), NMPA Key Laboratory for Research and Evaluation of Radiopharmaceuticals (National Medical Products Administration), Department of Nuclear Medicine, Peking University Cancer Hospital and Institute, Beijing 100142, China
| | - Jin Ding
- Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), NMPA Key Laboratory for Research and Evaluation of Radiopharmaceuticals (National Medical Products Administration), Department of Nuclear Medicine, Peking University Cancer Hospital and Institute, Beijing 100142, China
| | - Yan Chen
- Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), NMPA Key Laboratory for Research and Evaluation of Radiopharmaceuticals (National Medical Products Administration), Department of Nuclear Medicine, Peking University Cancer Hospital and Institute, Beijing 100142, China.,Guizhou University School of Medicine, Guiyang, Guizhou 550025, People's Republic of China
| | - Zilei Wang
- Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), NMPA Key Laboratory for Research and Evaluation of Radiopharmaceuticals (National Medical Products Administration), Department of Nuclear Medicine, Peking University Cancer Hospital and Institute, Beijing 100142, China.,Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Southwest Medical University, Luzhou 646000, China
| | - Hua Zhu
- Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), NMPA Key Laboratory for Research and Evaluation of Radiopharmaceuticals (National Medical Products Administration), Department of Nuclear Medicine, Peking University Cancer Hospital and Institute, Beijing 100142, China.,Institute of Biomedical Engineering, Peking University Shenzhen Graduate School, Shenzhen, Guangdong 518055, China
| | - Zhi Yang
- Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), NMPA Key Laboratory for Research and Evaluation of Radiopharmaceuticals (National Medical Products Administration), Department of Nuclear Medicine, Peking University Cancer Hospital and Institute, Beijing 100142, China.,Institute of Biomedical Engineering, Peking University Shenzhen Graduate School, Shenzhen, Guangdong 518055, China
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Mesothelin: An Immunotherapeutic Target beyond Solid Tumors. Cancers (Basel) 2022; 14:cancers14061550. [PMID: 35326701 PMCID: PMC8946840 DOI: 10.3390/cancers14061550] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Revised: 03/12/2022] [Accepted: 03/17/2022] [Indexed: 02/04/2023] Open
Abstract
Simple Summary This review summarizes the current knowledge on mesothelin’s function, its role in cancer, and opportunities for immunotherapeutic targeting of mesothelin. Immunotherapies including monoclonal antibodies, antibody–drug conjugates, chimeric antigen receptor T and NK-cells, targeted alpha therapies, and bispecific T cell engaging molecules are reviewed. We show future directions for mesothelin targeting in hematological malignancies, including acute myeloid leukemia. Abstract Modern targeted cancer therapies rely on the overexpression of tumor associated antigens with very little to no expression in normal cell types. Mesothelin is a glycosylphosphatidylinositol-anchored cell surface protein that has been identified in many different tumor types, including lung adenocarcinomas, ovarian carcinomas, and most recently in hematological malignancies, including acute myeloid leukemia (AML). Although the function of mesothelin is widely unknown, interactions with MUC16/CA125 indicate that mesothelin plays a role in the regulation of proliferation, growth, and adhesion signaling. Most research on mesothelin currently focuses on utilizing mesothelin to design targeted cancer therapies such as monoclonal antibodies, antibody–drug conjugates, chimeric antigen receptor T and NK cells, bispecific T cell engaging molecules, and targeted alpha therapies, amongst others. Both in vitro and in vivo studies using different immunotherapeutic modalities in mesothelin-positive AML models highlight the potential impact of this approach as a unique opportunity to treat hard-to-cure AML.
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Kreitman RJ, Pastan I. Immunotoxins: From Design to Clinical Application. Biomolecules 2021; 11:1696. [PMID: 34827694 PMCID: PMC8615697 DOI: 10.3390/biom11111696] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Accepted: 11/01/2021] [Indexed: 12/19/2022] Open
Abstract
The Special Issue of Biomolecules entitled "Immunotoxins, From Design to Clinical Application" contains seven reviews related to immunotoxins [...].
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Affiliation(s)
- Robert J. Kreitman
- Laboratory of Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA;
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Immunotherapy-based targeting of MSLN + activated portal fibroblasts is a strategy for treatment of cholestatic liver fibrosis. Proc Natl Acad Sci U S A 2021; 118:2101270118. [PMID: 34253615 DOI: 10.1073/pnas.2101270118] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
We investigated the role of mesothelin (Msln) and thymocyte differentiation antigen 1 (Thy1) in the activation of fibroblasts across multiple organs and demonstrated that Msln-/- mice are protected from cholestatic fibrosis caused by Mdr2 (multidrug resistance gene 2) deficiency, bleomycin-induced lung fibrosis, and UUO (unilateral urinary obstruction)-induced kidney fibrosis. On the contrary, Thy1-/- mice are more susceptible to fibrosis, suggesting that a Msln-Thy1 signaling complex is critical for tissue fibroblast activation. A similar mechanism was observed in human activated portal fibroblasts (aPFs). Targeting of human MSLN+ aPFs with two anti-MSLN immunotoxins killed fibroblasts engineered to express human mesothelin and reduced collagen deposition in livers of bile duct ligation (BDL)-injured mice. We provide evidence that antimesothelin-based therapy may be a strategy for treatment of parenchymal organ fibrosis.
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A Novel 89Zr-labeled DDS Device Utilizing Human IgG Variant (scFv): "Lactosome" Nanoparticle-Based Theranostics for PET Imaging and Targeted Therapy. Life (Basel) 2021; 11:life11020158. [PMID: 33670777 PMCID: PMC7923095 DOI: 10.3390/life11020158] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Revised: 02/13/2021] [Accepted: 02/15/2021] [Indexed: 12/22/2022] Open
Abstract
“Theranostics,” a new concept of medical advances featuring a fusion of therapeutic and diagnostic systems, provides promising prospects in personalized medicine, especially cancer. The theranostics system comprises a novel 89Zr-labeled drug delivery system (DDS), derived from the novel biodegradable polymeric micelle, “Lactosome” nanoparticles conjugated with specific shortened IgG variant, and aims to successfully deliver therapeutically effective molecules, such as the apoptosis-inducing small interfering RNA (siRNA) intracellularly while offering simultaneous tumor visualization via PET imaging. A 27 kDa-human single chain variable fragment (scFv) of IgG to establish clinically applicable PET imaging and theranostics in cancer medicine was fabricated to target mesothelin (MSLN), a 40 kDa-differentiation-related cell surface glycoprotein antigen, which is frequently and highly expressed by malignant tumors. This system coupled with the cell penetrating peptide (CPP)-modified and photosensitizer (e.g., 5, 10, 15, 20-tetrakis (4-aminophenyl) porphyrin (TPP))-loaded Lactosome particles for photochemical internalized (PCI) driven intracellular siRNA delivery and the combination of 5-aminolevulinic acid (ALA) photodynamic therapy (PDT) offers a promising nano-theranostic-based cancer therapy via its targeted apoptosis-inducing feature. This review focuses on the combined advances in nanotechnology and material sciences utilizing the “89Zr-labeled CPP and TPP-loaded Lactosome particles” and future directions based on important milestones and recent developments in this platform.
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Wang X, Ma W, Liu W, Ma H, Yang Y, Wang Y, Liu N, Yang G. Construction and Preclinical Evaluation of 211At Labeled Anti-mesothelin Antibodies as Potential Targeted Alpha Therapy Drugs. JOURNAL OF RADIATION RESEARCH 2020; 61:684-690. [PMID: 32648573 PMCID: PMC7482154 DOI: 10.1093/jrr/rraa049] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Revised: 05/15/2020] [Indexed: 05/04/2023]
Abstract
Targeted alpha therapy (TAT) is a promising tumor therapy that can specifically transport α particle to the vicinity of tumor cells while the normal cells are only slightly irradiated. Mesothelin is a highly promising molecular signature for many types of solid tumors including malignant mesothelioma, pancreatic cancer, ovarian cancer and lung adenocarcinoma etc., while the expression in normal human tissues are limited, thus making mesothelin a promising antigen for TAT. Previously we developed a theoretical model that could predict and optimize in vitro screening of potential TAT drugs. The aim of the study is construction and preclinical evaluation of 211At labeled anti-mesothelin antibodies as potential TAT drugs. Mesothelin expression of two tumor cell lines were confirmed by flow cytometry, and their radiosensitivities were also evaluated. We used two kinds of anti-mesothelin antibodies, ET210-6 and ET210-28, to construct TAT drugs. Then, radiochemical purity, stability in vitro, affinity of the conjugates and mesothelin expression level were assessed. The specific killing of mesothelin-positive cancer cells treated by 211At-ET210-28 and 211At-ET210-6 were studied via Cell Counting Kit-8 assay and colony formation assay. 211At-ET210-28 and 211At-ET210-6 revealed excellent affinity and stability in both phosphate buffer saline and fetal bovine serum environment. Radiolabeled antibody conjugates bound specifically to mesothelin-positive cells in vitro. Both 211At-ET210-28 and 211At-ET210-6 could specifically kill mesothelin-positive cells with negligible damages to mesothelin-negative cells. Our findings provide initial proof-of-concept for the potential use of 211At labeled ET210-28/ET210-6 anti-mesothelin antibody in specific killings of mesothelin-positive tumor cells.
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Affiliation(s)
- Xudong Wang
- State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871, P. R. China
| | - Wenzong Ma
- State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871, P. R. China
| | - Weihao Liu
- Key Laboratory of Radiation Physics and Technology, Ministry of Education, Institute of Nuclear Science and Technology, Sichuan University, Chengdu 610064, P. R. China
| | - Huan Ma
- Key Laboratory of Radiation Physics and Technology, Ministry of Education, Institute of Nuclear Science and Technology, Sichuan University, Chengdu 610064, P. R. China
| | - Yuanyou Yang
- Key Laboratory of Radiation Physics and Technology, Ministry of Education, Institute of Nuclear Science and Technology, Sichuan University, Chengdu 610064, P. R. China
| | - Yugang Wang
- State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871, P. R. China
| | - Ning Liu
- Key Laboratory of Radiation Physics and Technology, Ministry of Education, Institute of Nuclear Science and Technology, Sichuan University, Chengdu 610064, P. R. China
| | - Gen Yang
- State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871, P. R. China
- Corresponding author. Dr. Gen Yang, State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Chengfu Road 201, Haidian District, Beijing 100871, P. R. China. , Phone: +86-10-6275-1879, Fax: +86-10-6275-1875
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Montemagno C, Cassim S, Pouyssegur J, Broisat A, Pagès G. From Malignant Progression to Therapeutic Targeting: Current Insights of Mesothelin in Pancreatic Ductal Adenocarcinoma. Int J Mol Sci 2020; 21:E4067. [PMID: 32517181 PMCID: PMC7312874 DOI: 10.3390/ijms21114067] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 05/19/2020] [Accepted: 05/20/2020] [Indexed: 02/06/2023] Open
Abstract
Pancreatic ductal adenocarcinoma (PDAC), accounting for 90% of all pancreatic tumors, is a highly devastating disease with poor prognosis and rising incidence. The lack of available specific diagnostics tests and the limited treatment opportunities contribute to this pejorative issue. Over the last 10 years, a growing interest pointing towards mesothelin (MSLN) as a promising PDAC-associated antigen has emerged. The limited expression of MSLN in normal tissues (peritoneum, pleura and pericardium) and its overexpression in 80 to 90% of PDAC make it an attractive candidate for therapeutic management of PDAC patients. Moreover, its role in malignant progression related to its involvement in tumor cell proliferation and resistance to chemotherapy has highlighted the relevance of its targeting. Hence, several clinical trials are investigating anti-MSLN efficacy in PDAC. In this review, we provide a general overview of the different roles sustained by MSLN during PDAC progression. Finally, we also summarize the different MSLN-targeted therapies that are currently tested in the clinic.
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Affiliation(s)
- Christopher Montemagno
- Département de Biologie Médicale, Centre Scientifique de Monaco, 98000 Monaco, Monaco; (S.C.); (J.P.); (G.P.)
- Institute for Research on Cancer and Aging of Nice, Université Cote d’Azur, CNRS UMR 7284, INSERM U1081, Centre Antoine Lacassagne, 06200 Nice, France
| | - Shamir Cassim
- Département de Biologie Médicale, Centre Scientifique de Monaco, 98000 Monaco, Monaco; (S.C.); (J.P.); (G.P.)
| | - Jacques Pouyssegur
- Département de Biologie Médicale, Centre Scientifique de Monaco, 98000 Monaco, Monaco; (S.C.); (J.P.); (G.P.)
- Institute for Research on Cancer and Aging of Nice, Université Cote d’Azur, CNRS UMR 7284, INSERM U1081, Centre Antoine Lacassagne, 06200 Nice, France
| | - Alexis Broisat
- Laboratoire Radiopharmaceutiques Biocliniques, INSERM, 1039-Université de Grenoble, 38700 La Tronche, France;
| | - Gilles Pagès
- Département de Biologie Médicale, Centre Scientifique de Monaco, 98000 Monaco, Monaco; (S.C.); (J.P.); (G.P.)
- Institute for Research on Cancer and Aging of Nice, Université Cote d’Azur, CNRS UMR 7284, INSERM U1081, Centre Antoine Lacassagne, 06200 Nice, France
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Abstract
CAR-T cell therapy targeting CD19 has achieved remarkable success in the treatment of B cell malignancies, while various solid malignancies are still refractory for lack of suitable target. In recent years, a large number of studies have sought to find suitable targets with low “on target, off tumor” concern for the treatment of solid tumors. Mesothelin (MSLN), a tumor-associated antigen broadly overexpressed on various malignant tumor cells, while its expression is generally limited to normal mesothelial cells, is an attractive candidate for targeted therapy. Strategies targeting MSLN, including antibody-based drugs, vaccines and CAR-T therapies, have been assessed in a large number of preclinical investigations and clinical trials. In particular, the development of CAR-T therapy has shown great promise as a treatment for various types of cancers. The safety, efficacy, doses, and pharmacokinetics of relevant strategies have been evaluated in many clinical trials. This review is intended to provide a brief overview of the characteristics of mesothelin and the development of strategies targeting MSLN for solid tumors. Further, we discussed the challenges and proposed potential strategies to improve the efficacy of MSLN targeted immunotherapy.
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Affiliation(s)
- Jiang Lv
- 1Key Laboratory of Regenerative Biology, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China.,2Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China.,3University of Chinese Academy of Sciences, Shijingshan District, Beijing, China
| | - Peng Li
- 1Key Laboratory of Regenerative Biology, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China.,2Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China
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Abstract
Mesothelin (MSLN) is considered a promising target for cancer therapy. Originally extracted in 1992 after the immunization of mice with a human ovarian cancer (OC) cell line and cloned in 1996, MSLN seems to be involved in cell adhesion and metastasis. MSLN is prevalent in mesothelia tissues but is expressed in several human cancers, such as OC, pancreatic cancer, mesothelioma, and lung cancer. Amatuximab (MORAb-009) is a mouse-human chimeric monoclonal antibody with a selective affinity for MSLN. The principal mechanism of action comprises inhibition of binding of MSLN with the antigen CA125/MUC16. The highest phase of development is actually a Phase II trial (MORAb-009-201, Europe). In this review, we describe the mechanism of action of amatuximab and other MSLN-targeting novel drugs, along with a discussion about the expected efficacy, safety, and toxicity of this promising group of agents and implications for future research and clinical practice.
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Affiliation(s)
- Paolo Baldo
- Pharmacy Unit, Directorate Department, CRO Aviano-IRCCS National Cancer Institute, Aviano, Italy
| | - Sara Cecco
- Pharmacy Unit, Directorate Department, CRO Aviano-IRCCS National Cancer Institute, Aviano, Italy
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Hassan R, Thomas A, Alewine C, Le DT, Jaffee EM, Pastan I. Mesothelin Immunotherapy for Cancer: Ready for Prime Time? J Clin Oncol 2016; 34:4171-4179. [PMID: 27863199 DOI: 10.1200/jco.2016.68.3672] [Citation(s) in RCA: 223] [Impact Index Per Article: 27.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Mesothelin is a tumor antigen that is highly expressed in many human cancers, including malignant mesothelioma and pancreatic, ovarian, and lung adenocarcinomas. It is an attractive target for cancer immunotherapy because its normal expression is limited to mesothelial cells, which are dispensable. Several antibody-based therapeutic agents as well as vaccine and T-cell therapies directed at mesothelin are undergoing clinical evaluation. These include antimesothelin immunotoxins (SS1P, RG7787/LMB-100), chimeric antimesothelin antibody (amatuximab), mesothelin-directed antibody drug conjugates (anetumab ravtansine, DMOT4039A, BMS-986148), live attenuated Listeria monocytogenes-expressing mesothelin (CRS-207, JNJ-64041757), and chimeric antigen receptor T-cell therapies. Two antimesothelin agents are currently in multicenter clinical registration trials for malignant mesothelioma: amatuximab in the first-line setting and anetumab ravtansine as second-line therapy. Phase II randomized clinical trials of CRS-207 as a boosting agent and in combination with immune checkpoint inhibition for pancreatic cancer are nearing completion. These ongoing studies will define the utility of mesothelin immunotherapy for treating cancer.
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Affiliation(s)
- Raffit Hassan
- Raffit Hassan, Anish Thomas, Christine Alewine, and Ira Pastan, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda; and Dung T. Le and Elizabeth M. Jaffee, Sidney Kimmel Cancer Center, Johns Hopkins University, Baltimore, MD
| | - Anish Thomas
- Raffit Hassan, Anish Thomas, Christine Alewine, and Ira Pastan, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda; and Dung T. Le and Elizabeth M. Jaffee, Sidney Kimmel Cancer Center, Johns Hopkins University, Baltimore, MD
| | - Christine Alewine
- Raffit Hassan, Anish Thomas, Christine Alewine, and Ira Pastan, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda; and Dung T. Le and Elizabeth M. Jaffee, Sidney Kimmel Cancer Center, Johns Hopkins University, Baltimore, MD
| | - Dung T Le
- Raffit Hassan, Anish Thomas, Christine Alewine, and Ira Pastan, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda; and Dung T. Le and Elizabeth M. Jaffee, Sidney Kimmel Cancer Center, Johns Hopkins University, Baltimore, MD
| | - Elizabeth M Jaffee
- Raffit Hassan, Anish Thomas, Christine Alewine, and Ira Pastan, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda; and Dung T. Le and Elizabeth M. Jaffee, Sidney Kimmel Cancer Center, Johns Hopkins University, Baltimore, MD
| | - Ira Pastan
- Raffit Hassan, Anish Thomas, Christine Alewine, and Ira Pastan, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda; and Dung T. Le and Elizabeth M. Jaffee, Sidney Kimmel Cancer Center, Johns Hopkins University, Baltimore, MD
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Lamberts LE, Menke-van der Houven van Oordt CW, ter Weele EJ, Bensch F, Smeenk MM, Voortman J, Hoekstra OS, Williams SP, Fine BM, Maslyar D, de Jong JR, Gietema JA, Schröder CP, Bongaerts AHH, Lub-de Hooge MN, Verheul HMW, Sanabria Bohorquez SM, Glaudemans AWJM, de Vries EGE. ImmunoPET with Anti-Mesothelin Antibody in Patients with Pancreatic and Ovarian Cancer before Anti-Mesothelin Antibody-Drug Conjugate Treatment. Clin Cancer Res 2015; 22:1642-52. [PMID: 26589435 DOI: 10.1158/1078-0432.ccr-15-1272] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Accepted: 10/20/2015] [Indexed: 11/16/2022]
Abstract
PURPOSE Mesothelin (MSLN) is frequently overexpressed in pancreatic and ovarian cancers, making it a potential drug target. We performed an (89)Zr-PET imaging study with MMOT0530A, a MSLN antibody, in conjunction with a phase I study with the antibody-drug conjugate DMOT4039A, containing MMOT0530A bound to MMAE. The aim was to study antibody tumor uptake, whole-body distribution, and relation between uptake, response to treatment, and MSLN expression. EXPERIMENTAL DESIGN Before DMOT4039A treatment, patients received 37 MBq (89)Zr-MMOT0530A followed by PET/CT imaging 2, 4, and 7 days postinjection. Tracer uptake was expressed as standardized uptake value (SUV). MSLN expression was determined with immunohistochemistry (IHC) on archival tumor tissue. RESULTS Eleven patients were included, 7 with pancreatic and 4 with ovarian cancer. IHC MSLN expression varied from absent to strong. Suitable tracer antibody dose was 10 mg MMOT0530A and optimal imaging time was 4 and 7 days postinjection. Tumor tracer uptake occurred in 37 lesions with mean SUVmax of 13.1 (±7.5) on PET 4 days postinjection, with 11.5 (±7.5) in (N= 17) pancreatic and 14.5 (±8.7) in (N= 20) ovarian cancer lesions. Within patients, a mean 2.4-fold (±1.10) difference in uptake between tumor lesions existed. Uptake in blood, liver, kidneys, spleen, and intestine reflected normal antibody distribution. Tracer tumor uptake was correlated to IHC. Best response to DMOT4039A was partial response in one patient. CONCLUSIONS With (89)Zr-MMOT0530A-PET, pancreatic and ovarian cancer lesions as well as antibody biodistribution could be visualized. This technique can potentially guide individualized antibody-based treatment.
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Affiliation(s)
- Laetitia E Lamberts
- Department of Medical Oncology, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
| | | | - Eva J ter Weele
- Department of Medical Oncology, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands. Department of Clinical Pharmacy and Pharmacology, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
| | - Frederike Bensch
- Department of Medical Oncology, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
| | - Michiel M Smeenk
- Department of Medical Oncology, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
| | - Johannes Voortman
- Department of Medical Oncology, VU University Medical Center, Amsterdam, the Netherlands
| | - Otto S Hoekstra
- Department of Radiology and Nuclear Medicine, VU University Medical Center, Amsterdam, the Netherlands
| | - Simon P Williams
- Department of Early Clinical Development, Genentech, Inc. South San Francisco, California
| | - Bernard M Fine
- Department of Biomedical Imaging, Genentech, Inc. South San Francisco, California
| | - Daniel Maslyar
- Department of Biomedical Imaging, Genentech, Inc. South San Francisco, California
| | - Johan R de Jong
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
| | - Jourik A Gietema
- Department of Medical Oncology, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
| | - Carolien P Schröder
- Department of Medical Oncology, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
| | - Alphons H H Bongaerts
- Department of Radiology, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
| | - Marjolijn N Lub-de Hooge
- Department of Clinical Pharmacy and Pharmacology, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands. Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
| | - Henk M W Verheul
- Department of Medical Oncology, VU University Medical Center, Amsterdam, the Netherlands
| | | | - Andor W J M Glaudemans
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
| | - Elisabeth G E de Vries
- Department of Medical Oncology, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands.
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Mason-Osann E, Hollevoet K, Niederfellner G, Pastan I. Quantification of recombinant immunotoxin delivery to solid tumors allows for direct comparison of in vivo and in vitro results. Sci Rep 2015; 5:10832. [PMID: 26111884 PMCID: PMC4482048 DOI: 10.1038/srep10832] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Accepted: 04/28/2015] [Indexed: 01/04/2023] Open
Abstract
Solid tumors present challenges for delivery of protein therapeutics; current methods cannot quantify the functional effects of these agents. RG7787 (anti-mesothelin recombinant immunotoxin) is highly cytotoxic to pancreatic cancer cell lines, but with limited activity in vivo. To investigate this discrepancy, we developed a flow cytometry method to quantify the amount of RG7787 internalized per cell in tumors and used it to analyze tumor responses by determining the number of molecules of RG7787 internalized per cell in vivo and comparing it to that needed to kill cells in vitro. At a maximum tolerated dose of 7.5 mg/kg, tumor cells in vivo internalized a wide range of RG7787 with the average amount equivalent to the amount that induced growth arrest in vitro. However, 20% of cells accumulated 20,300 ITs per cell, sufficient to kill cells in vitro. At 2.5 mg/kg the top 20% of cells internalized enough RG7787 to only induce growth arrest. These data are in agreement with tumor responses; 22% regression following a 7.5 mg/kg dose and growth stabilization following 2.5 mg/kg. Comparing amounts of RIT delivered in vivo and in vitro can explain tumor responses and should facilitate the development of more active immunotoxins and other antibody based agents.
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Affiliation(s)
- Emily Mason-Osann
- Laboratory of Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Kevin Hollevoet
- Laboratory of Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Gerhard Niederfellner
- Roche Pharmaceutical Research &Early Development, Discovery Oncology, Innovation Center Penzberg, Roche Diagnostics GmbH, Nonnenwald 2, 82377 Penzberg, Germany
| | - Ira Pastan
- Laboratory of Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA
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A novel PET imaging using ⁶⁴Cu-labeled monoclonal antibody against mesothelin commonly expressed on cancer cells. J Immunol Res 2015; 2015:268172. [PMID: 25883990 PMCID: PMC4390102 DOI: 10.1155/2015/268172] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2014] [Revised: 02/14/2015] [Accepted: 02/19/2015] [Indexed: 01/27/2023] Open
Abstract
Mesothelin (MSLN) is a 40-kDa cell differentiation-associated glycoprotein appearing with carcinogenesis and is highly expressed in many human cancers, including the majority of pancreatic adenocarcinomas, ovarian cancers, and mesotheliomas, while its expression in normal tissue is limited to mesothelial cells lining the pleura, pericardium, and peritoneum. Clone 11-25 is a murine hybridoma secreting monoclonal antibody (mAb) against human MSLN. In this study, we applied the 11-25 mAb to in vivo imaging to detect MSLN-expressing tumors. In in vitro and ex vivo immunochemical studies, we demonstrated specificity of 11-25 mAb to membranous MSLN expressed on several pancreatic cancer cells. We showed the accumulation of Alexa Fluor 750-labeled 11-25 mAb in MSLN-expressing tumor xenografts in athymic nude mice. Then, 11-25 mAb was labeled with 64Cu via a chelating agent DOTA and was used in both in vitro cell binding assay and in vivo positron emission tomography (PET) imaging in the tumor-bearing mice. We confirmed that 64Cu-labeled 11-25 mAb highly accumulated in MSLN-expressing tumors as compared to MSLN-negative ones. The 64Cu-labeled 11-25 mAb is potentially useful as a PET probe capable of being used for wide range of tumors, rather than 18F-FDG that occasionally provides nonspecific accumulation into the inflammatory lesions.
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Scales SJ, Gupta N, Pacheco G, Firestein R, French DM, Koeppen H, Rangell L, Barry-Hamilton V, Luis E, Chuh J, Zhang Y, Ingle GS, Fourie-O'Donohue A, Kozak KR, Ross S, Dennis MS, Spencer SD. An antimesothelin-monomethyl auristatin e conjugate with potent antitumor activity in ovarian, pancreatic, and mesothelioma models. Mol Cancer Ther 2014; 13:2630-40. [PMID: 25249555 DOI: 10.1158/1535-7163.mct-14-0487-t] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Mesothelin (MSLN) is an attractive target for antibody-drug conjugate therapy because it is highly expressed in various epithelial cancers, with normal expression limited to nondividing mesothelia. We generated novel antimesothelin antibodies and conjugated an internalizing one (7D9) to the microtubule-disrupting drugs monomethyl auristatin E (MMAE) and MMAF, finding the most effective to be MMAE with a lysosomal protease-cleavable valine-citrulline linker. The humanized (h7D9.v3) version, αMSLN-MMAE, specifically targeted mesothelin-expressing cells and inhibited their proliferation with an IC50 of 0.3 nmol/L. Because the antitumor activity of an antimesothelin immunotoxin (SS1P) in transfected mesothelin models did not translate to the clinic, we carefully selected in vivo efficacy models endogenously expressing clinically relevant levels of mesothelin, after scoring mesothelin levels in ovarian, pancreatic, and mesothelioma tumors by immunohistochemistry. We found that endogenous mesothelin in cancer cells is upregulated in vivo and identified two suitable xenograft models for each of these three indications. A single dose of αMSLN-MMAE profoundly inhibited or regressed tumor growth in a dose-dependent manner in all six models, including two patient-derived tumor xenografts. The robust and durable efficacy of αMSLN-MMAE in preclinical models of ovarian, mesothelioma, and pancreatic cancers justifies the ongoing phase I clinical trial.
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Affiliation(s)
- Suzie J Scales
- Department of Molecular Biology, Genentech, South San Francisco, California.
| | - Nidhi Gupta
- Department of Molecular Biology, Genentech, South San Francisco, California
| | - Glenn Pacheco
- Department of Translational Oncology, Genentech, South San Francisco, California
| | - Ron Firestein
- Department of Pathology, Genentech, South San Francisco, California
| | - Dorothy M French
- Department of Pathology, Genentech, South San Francisco, California
| | - Hartmut Koeppen
- Department of Pathology, Genentech, South San Francisco, California
| | - Linda Rangell
- Department of Pathology, Genentech, South San Francisco, California
| | | | - Elizabeth Luis
- Department of Protein Chemistry, Genentech, South San Francisco, California
| | - Josefa Chuh
- Department of Biochemical and Cellular Pharmacology, Genentech, South San Francisco, California
| | - Yin Zhang
- Department of Antibody Engineering, Genentech, South San Francisco, California
| | - Gladys S Ingle
- Department of Molecular Biology, Genentech, South San Francisco, California
| | - Aimee Fourie-O'Donohue
- Department of Biochemical and Cellular Pharmacology, Genentech, South San Francisco, California
| | - Katherine R Kozak
- Department of Biochemical and Cellular Pharmacology, Genentech, South San Francisco, California
| | - Sarajane Ross
- Department of Translational Oncology, Genentech, South San Francisco, California
| | - Mark S Dennis
- Department of Antibody Engineering, Genentech, South San Francisco, California
| | - Susan D Spencer
- Department of Translational Oncology, Genentech, South San Francisco, California
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Abstract
We have recently reported that an immunotoxin targeting mesothelin produced durable major tumor regressions in patients with extensive treatment-refractory mesothelioma. These unprecedented tumor responses have prompted us to review how mesothelin was discovered and the advances that led to these tumor responses. This review is not comprehensive but focuses on major developments over the past 20 years since mesothelin was first identified in our laboratory. Mesothelin is a cell-surface glycoprotein whose expression in normal human tissues is restricted to mesothelial cells. Because it is highly expressed by many solid tumors, it is an attractive immunotherapy target. Antibody-based therapies currently in clinical trials include an immunotoxin, a chimeric monoclonal antibody, and an antibody drug conjugate. In addition, a mesothelin tumor vaccine and a mesothelin- chimeric antigen receptor are being evaluated in the clinic. SS1P, an anti-mesothelin immunotoxin, was the first mesothelin-directed therapy to enter the clinic, and its use showed that mesothelin-targeted therapy was safe in patients. More importantly, our recent work has shown that SS1P in combination with pentostatin and cyclophosphamide can result in durable tumor regression in patients with advanced mesothelioma and opens up the possibility that such an approach can benefit patients with many common cancers.
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Affiliation(s)
- Ira Pastan
- Authors' Affiliation: Laboratory of Molecular Biology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, Maryland
| | - Raffit Hassan
- Authors' Affiliation: Laboratory of Molecular Biology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, Maryland
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Wang K, Bodempudi V, Liu Z, Borrego-Diaz E, Yamoutpoor F, Meyer A, Woo RA, Pan W, Dudek AZ, Olyaee MS, Esfandyari T, Farassati F. Inhibition of mesothelin as a novel strategy for targeting cancer cells. PLoS One 2012; 7:e33214. [PMID: 22485139 PMCID: PMC3317639 DOI: 10.1371/journal.pone.0033214] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2011] [Accepted: 02/05/2012] [Indexed: 12/15/2022] Open
Abstract
Mesothelin, a differentiation antigen present in a series of malignancies such as mesothelioma, ovarian, lung and pancreatic cancer, has been studied as a marker for diagnosis and a target for immunotherapy. We, however, were interested in evaluating the effects of direct targeting of Mesothelin on the viability of cancer cells as the first step towards developing a novel therapeutic strategy. We report here that gene specific silencing for Mesothelin by distinct methods (siRNA and microRNA) decreased viability of cancer cells from different origins such as mesothelioma (H2373), ovarian cancer (Skov3 and Ovcar-5) and pancreatic cancer (Miapaca2 and Panc-1). Additionally, the invasiveness of cancer cells was also significantly decreased upon such treatment. We then investigated pro-oncogenic signaling characteristics of cells upon mesothelin-silencing which revealed a significant decrease in phospho-ERK1 and PI3K/AKT activity. The molecular mechanism of reduced invasiveness was connected to the reduced expression of β-Catenin, an important marker of EMT (epithelial-mesenchymal transition). Ero1, a protein involved in clearing unfolded proteins and a member of the ER-Stress (endoplasmic reticulum-stress) pathway was also markedly reduced. Furthermore, Mesothelin silencing caused a significant increase in fraction of cancer cells in S-phase. In next step, treatment of ovarian cancer cells (OVca429) with a lentivirus expressing anti-mesothelin microRNA resulted in significant loss of viability, invasiveness, and morphological alterations. Therefore, we propose the inhibition of Mesothelin as a potential novel strategy for targeting human malignancies.
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Affiliation(s)
- Kun Wang
- Molecular Medicine Laboratory, Divisions of Gastroenterology and Hematology/Oncology, Department of Medicine, The University of Kansas Medical Center, Kansas City, Kansas, United States of America
| | - Vidya Bodempudi
- Department of Medicine, The University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Zhengian Liu
- Molecular Medicine Laboratory, Divisions of Gastroenterology and Hematology/Oncology, Department of Medicine, The University of Kansas Medical Center, Kansas City, Kansas, United States of America
| | - Emma Borrego-Diaz
- Molecular Medicine Laboratory, Divisions of Gastroenterology and Hematology/Oncology, Department of Medicine, The University of Kansas Medical Center, Kansas City, Kansas, United States of America
| | - Farnaz Yamoutpoor
- Molecular Medicine Laboratory, Divisions of Gastroenterology and Hematology/Oncology, Department of Medicine, The University of Kansas Medical Center, Kansas City, Kansas, United States of America
| | - Anna Meyer
- Department of Medicine, The University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Richard A. Woo
- Southern Illinois University Medical Center, Springfield, Illinois, United States of America
| | - Weihong Pan
- Molecular Medicine Laboratory, Divisions of Gastroenterology and Hematology/Oncology, Department of Medicine, The University of Kansas Medical Center, Kansas City, Kansas, United States of America
| | - Arkadiusz Z. Dudek
- Department of Medicine, The University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Mojtaba S. Olyaee
- Molecular Medicine Laboratory, Divisions of Gastroenterology and Hematology/Oncology, Department of Medicine, The University of Kansas Medical Center, Kansas City, Kansas, United States of America
| | - Tuba Esfandyari
- Molecular Medicine Laboratory, Divisions of Gastroenterology and Hematology/Oncology, Department of Medicine, The University of Kansas Medical Center, Kansas City, Kansas, United States of America
| | - Faris Farassati
- Molecular Medicine Laboratory, Divisions of Gastroenterology and Hematology/Oncology, Department of Medicine, The University of Kansas Medical Center, Kansas City, Kansas, United States of America
- * E-mail:
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Singh R, Zhang Y, Pastan I, Kreitman RJ. Synergistic antitumor activity of anti-CD25 recombinant immunotoxin LMB-2 with chemotherapy. Clin Cancer Res 2012; 18:152-60. [PMID: 22068660 PMCID: PMC3251712 DOI: 10.1158/1078-0432.ccr-11-1839] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE Although anti-CD25 recombinant immunotoxin LMB-2 is effective against CD25(+) hairy cell leukemia, activity against more aggressive diseases such as adult T-cell leukemia (ATL) is limited by rapid disease progression between treatment cycles. Our goal was to determine in vivo whether rapid growth of CD25(+) tumor is associated with high levels of tumor interstitial soluble CD25 (sCD25) and whether chemotherapy can reduce tumor sCD25 and synergize with LMB-2. EXPERIMENTAL DESIGN Tumor xenografts expressing human CD25 were grown in mice, which were then treated with LMB-2 and chemotherapy either alone or in combination, and sCD25 level and antitumor activity were measured. RESULTS CD25(+) human xenografts growing rapidly in nude mice had intratumoral sCD25 at levels that were between 21- and 2,200 (median 118)-fold higher than in serum, indicating that interstitial sCD25 interacts with LMB-2 in tumors. Intratumoral sCD25 levels were in the range 21 to 157 (median 54) ng/mL without treatment and 0.95 to 6.1 (median 2.6) ng/mL (P < 0.0001) 1 day after gemcitabine administration. CD25(+) xenografts that were too large to regress with LMB-2 alone were minimally responsive to gemcitabine alone but completely regressed with the combination. Ex vivo, different ratios of gemcitabine and LMB-2 were cytotoxic to the CD25(+) tumor cells in an additive, but not synergistic, manner. CONCLUSIONS Gemcitabine is synergistic with LMB-2 in vivo unrelated to improved cytotoxicity. Synergism, therefore, appears to be related to improved distribution of LMB-2 to CD25(+) tumors, and is preceded by decreased sCD25 within the tumor because of chemotherapy. To test the concept of combined treatment clinically, patients with relapsed/refractory ATL are being treated with fludarabine plus cyclophosphamide before LMB-2.
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Affiliation(s)
- Rajat Singh
- Laboratory of Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, 20892
| | - Yujian Zhang
- Laboratory of Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, 20892
| | - Ira Pastan
- Laboratory of Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, 20892
| | - Robert J. Kreitman
- Laboratory of Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, 20892
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18
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Shin IS, Lee SM, Kim HS, Yao Z, Regino C, Sato N, Cheng KT, Hassan R, Campo MF, Albone EF, Choyke PL, Pastan I, Paik CH. Effect of chelator conjugation level and injection dose on tumor and organ uptake of 111In-labeled MORAb-009, an anti-mesothelin antibody. Nucl Med Biol 2011; 38:1119-27. [PMID: 21741258 DOI: 10.1016/j.nucmedbio.2011.05.003] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2011] [Revised: 04/27/2011] [Accepted: 05/13/2011] [Indexed: 10/18/2022]
Abstract
INTRODUCTION Radiolabeling of a monoclonal antibody (mAb) with a metallic radionuclide requires the conjugation of a bifunctional chelator to the mAb. The conjugation, however, can alter the physical and immunological properties of the mAb, consequently affecting its tumor-targeting pharmacokinetics. In this study, we investigated the effect of the amount of 2-(p-isothiocyanatobenzyl)-cyclohexyl-diethylenetriamine-pentaacetic acid (CHX-A″) conjugated to MORAb-009, a mAb directed against mesothelin, and the effect of MORAb dose on the biodistribution of (111)In-labeled MORAb-009. METHODS We used nude mice bearing the A431/K5 tumor as a mesothelin-positive tumor model and the A431 tumor as a mesothelin-negative control. To find the optimal level of CHX-A″ conjugation, CHX-A″-MORAb-009 conjugates with 2.4, 3.5 and 5.5 CHX-A″ molecules were investigated. To investigate the effect of injected MORAb-009 dose on neutralizing the shed mesothelin in the circulation, biodistribution studies were performed after the intravenous co-injection of (111)In-labeled MORAb-009 (2.4 CHX-A″/MORAb-009) with three different doses: 0.2, 2 and 30 μg of MORAb-009. RESULTS The tumor uptake in A431/K5 tumor was four times higher than that in A431 tumor, indicating that the tumor uptake in A431/K5 was mesothelin mediated. The conjugate with 5.5 CHX-A″ showed a lower isoelectric point (pI) and lower immunoreactivity (IR) than the 2.4 CHX-A″ conjugate. These differences were reflected in the biodistribution of the (111)In label. The (111)In-labeled MORAb-009 conjugated with 2.4 CHX-A″ produced higher tumor uptake and lower liver and spleen uptakes than the 5.5 CHX-A″ conjugate. The biodistribution studies also revealed that the tumor uptake was significantly affected by the injected MORAb-009 dose and tumor size. The 30-μg dose produced higher tumor uptake than the 0.2- and 2-μg doses, whereas the 30-μg dose produced lower liver and spleen uptakes than the 0.2-μg dose. CONCLUSION This study demonstrates that the number of chelate conjugation and the injected dose are two important parameters to achieve high tumor and low non-target organ uptake of (111)In-labeled MORAb-009. This study also suggests that the injected dose of mAb could be individualized based on the tumor size or the blood level of shed antigen in a patient to achieve the ideal tumor-to-organ radioactivity ratios.
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Affiliation(s)
- In Soo Shin
- Radiopharmaceutical Laboratory, Division of Nuclear Medicine, Department of Radiology and Imaging Sciences, NIH Clinical Center, Bethesda, MD 20892, USA
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19
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Nowak AK, Francis RJ, Katz SI, Gerbaudo VH. A Multimodality Imaging Review of Malignant Pleural Mesothelioma Response Assessment. PET Clin 2011; 6:299-311. [PMID: 27156725 DOI: 10.1016/j.cpet.2011.04.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Assessment of response is important to interpret early phase clinical trial results and to guide individual patient management. In malignant pleural mesothelioma (MPM), the circumferential growth pattern of the disease, the presence of pleural effusion and atelectasis, and the common use of pleurodesis make this a challenging task for imaging specialists and clinicians. This article reviews the current evidence for radiological and positron emission tomography (PET) response assessment in MPM, and the pitfalls and challenges in its application. Current research and future directions in radiological and PET response are discussed, including the use of novel radiotracers.
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Affiliation(s)
- Anna K Nowak
- School of Medicine and Pharmacology, University of Western Australia, 35 Stirling Highway, Nedlands, Perth 6009, Western Australia, Australia; Department of Medical Oncology, Sir Charles Gairdner Hospital, Verdun Street, Nedlands, Perth 6009, Western Australia, Australia
| | - Roslyn J Francis
- School of Medicine and Pharmacology, University of Western Australia, 35 Stirling Highway, Nedlands, Perth 6009, Western Australia, Australia; Department of Medical Oncology, Sir Charles Gairdner Hospital, Verdun Street, Nedlands, Perth 6009, Western Australia, Australia
| | - Sharyn I Katz
- Department of Radiology, Hospital of the University of Pennsylvania, University of Pennsylvania School of Medicine, 1 Silverstein Building, 3400 Spruce Street, Philadelphia, PA 19104, USA
| | - Victor H Gerbaudo
- Division of Nuclear Medicine and Molecular Imaging, Brigham and Women's Hospital, Harvard Medical School, 75 Francis Street, Boston, MA 02115, USA
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Evaluation of (111)In labeled antibodies for SPECT imaging of mesothelin expressing tumors. Nucl Med Biol 2011; 38:885-96. [PMID: 21843785 DOI: 10.1016/j.nucmedbio.2011.02.013] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2010] [Revised: 02/01/2011] [Accepted: 02/27/2011] [Indexed: 01/24/2023]
Abstract
INTRODUCTION Mesothelin is expressed in many cancers, especially in mesothelioma and lung, pancreatic and ovarian cancers. In the present study, we evaluate (111)In labeled antimesothelin antibodies as an imaging bioprobe for the SPECT imaging of mesothelin-expressing tumors. METHODS We radiolabeled the antimesothelin antibodies mAbMB and mAbK1 with (111)In using the p-SCN-bn-DTPA chelator. The immunoreactivity, affinity (K(d)) and internalization properties of the resulting two (111)In labeled antibodies were evaluated in vitro using mesothelin-expressing A431K5 cells. The biodistribution and microSPECT/CT imaging studies with (111)In labeled antibodies were performed in mice bearing both mesothelin positive (A431K5) and mesothelin negative (A431) tumors. RESULTS In vitro studies demonstrated that (111)In-mAbMB bound with a higher affinity (K(d)=3.6±1.7 nM) to the mesothelin-expressing A431K5 cells than did the (111)In-mAbK1 (K(d)=29.3±2.3 nM). (111)In-mAbMB was also internalized at a greater rate and extent into the A431K5 cells than was the (111)In-mAbK1. Biodistribution studies showed that (111)In-mAbMB was preferentially localized in A431K5 tumors when compared to A431 tumors. At the low dose, the peak A431K5 tumor uptake of 9.65±2.65% ID/g (injected dose per gram) occurred at 48 h, while at high dose tumor uptake peaked with 14.29±6.18% ID/g at 72 h. Non-specific localization of (111)In-mAbMB was mainly observed in spleen.(111)In-mAbK1 also showed superior localization in A431K5 tumors than in A431 tumors, but the peak uptake was only 3.04±0.68% ID/g at 24 h. MicroSPECT/CT studies confirmed better visualization of A431K5 tumors with (111)In-mAbMB, than with (111)In-mAbK1. CONCLUSION SPECT imaging of mesothelin expressing tumors was demonstrated successfully. Our findings indicate that the antimesothelin antibody mAbMB has the potential to be developed into a diagnostic agent for imaging mesothelin-expressing cancers.
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Development of positron emission tomography imaging by 64Cu-labeled Fab for detecting ERC/mesothelin in a mesothelioma mouse model. Nucl Med Commun 2010; 31:380-8. [PMID: 20072072 DOI: 10.1097/mnm.0b013e328336733d] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Malignant mesothelioma is a highly aggressive form of cancer. Curative surgery is the only effective therapy for mesothelioma, and therefore early diagnosis is important. However, early diagnosis is difficult using current diagnostic imaging techniques, and a new imaging method for early diagnosis is urgently required. We evaluated the affinity of radiolabeled monoclonal antibodies to the C-terminal fragment of ERC/mesothelin for this purpose. METHODS In-labeled or I-labeled IgG against C-terminal fragment of ERC and its Fab fragment were evaluated in vitro by cell binding, competitive inhibition, and cellular internalization assays, and in vivo by biodistribution in mice bearing ERC-expressing tumors. Next, the Fab fragment was labeled with the positron emitter Cu and evaluated by positron emission tomography (PET). RESULTS Radiolabeled IgG and Fab showed specific binding to ERC-expressing mesothelioma cells with high affinity. Both radiolabeled IgG and Fab internalized into cells after binding to ERC on the cell surface. In-labeled IgG accumulated in ERC-expressing tumors and resulted in a moderate tumor-to-blood ratio at 4 days after injection. Furthermore, PET using Cu-labeled Fab visualized the tumor at 6 h after injection. CONCLUSION Cu-labeled Fab can be useful for ERC-specific PET imaging, and can thus facilitate improved diagnosis of patients with early-stage mesothelioma.
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Kreitman RJ, Hassan R, Fitzgerald DJ, Pastan I. Phase I trial of continuous infusion anti-mesothelin recombinant immunotoxin SS1P. Clin Cancer Res 2009; 15:5274-9. [PMID: 19671873 DOI: 10.1158/1078-0432.ccr-09-0062] [Citation(s) in RCA: 178] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
PURPOSE To conduct a phase I trial of recombinant immunotoxin SS1P given by continuous infusion in chemoresistant solid tumors expressing mesothelin. EXPERIMENTAL DESIGN Eligible patients had mesothelioma, ovarian, or pancreatic cancer, which was recurrent or unresectable despite standard therapy, and were mesothelin positive by immunohistochemistry. SS1P was given by continuous infusion for 10 days, and cycles could be repeated at 4-week intervals in the absence of neutralizing antibodies or progressive disease. RESULTS Twenty-four patients, five with peritoneal mesothelioma, nine with pleural mesothelioma, two with pleural-peritoneal mesothelioma, seven with ovarian carcinoma, and one with pancreatic carcinoma, received 4, 8, 12, 18, and 25 microg/kg/d x10. The maximum tolerated dose was 25 microg/kg/d x10, where one of six patients had dose-limiting toxicity due to reversible vascular leak syndrome. Immunogenicity was observed in 18 (75%) of 24 patients, and five (21%) received a second cycle. Constant plasma levels of SS1P were maintained for most of the 10-day infusion time, with median peak levels of up to 153 ng/mL. One patient had a partial response. Nonmajor responses included cessation of ascites and independence from paracentesis, resolution of masses by positron emission tomography, and improved pain and range of motion. CONCLUSIONS As a single agent by continuous infusion, recombinant immunotoxin SS1P was well tolerated up to 25 microg/kg/d x10 and showed evidence of modest clinical activity. Continuous infusion showed no significant advantage over bolus dosing, and further clinical development of SS1P is proceeding by bolus dosing in combination with chemotherapy.
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Affiliation(s)
- Robert J Kreitman
- Laboratory of Molecular Biology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, Maryland 20892-4264, USA.
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Chen KC, Kim J, Li X, Lee B. Modeling recombinant immunotoxin efficacies in solid tumors. Ann Biomed Eng 2008; 36:486-512. [PMID: 18183487 DOI: 10.1007/s10439-007-9425-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2007] [Accepted: 12/12/2007] [Indexed: 11/29/2022]
Abstract
Effectiveness of cancer therapy is improved by the use of recombinant immunotoxins (RITs) that target membrane proteins unique to malignant tumor cells. Although RIT antitumor activity in vivo can always be improved with larger doses, clinical restriction on the dose toleration makes it critical to explore how RIT antitumor activity can be maximized without resorting to dose elevation. In this work, a mathematical model was developed to explore functional correlations between the properties of several recombinant immunotoxins and their antitumor efficacies in vivo. Simulations were compared with experimental data of human tumor xenografts grown on nude mice to assess parameters critical to optimal antitumor activity. We dissected out or held constant as many parameters of the model as possible to investigate the effect of the remaining parameters on the behavior of the system as a whole. Empirical correlations between immunotoxin binding affinity and the target binding site density were obtained for several recombinant immunotoxins targeting either human A431 carcinoma or CD46 Burkitt's lymphoma. Simulations reinforced the idea of binding site barrier for drug diffusion and suggested that optimal antitumor activity was achieved when the binding affinity is logarithmically dependent on the target binding site density.
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Affiliation(s)
- Kevin C Chen
- Department of Biomedical Engineering, FAMU-FSU College of Engineering, Florida State University, Tallahassee, FL, 32310, USA.
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Armato SG, Entwisle J, Truong MT, Nowak AK, Ceresoli GL, Zhao B, Misri R, Kindler HL. Current state and future directions of pleural mesothelioma imaging. Lung Cancer 2007; 59:411-20. [PMID: 18061303 DOI: 10.1016/j.lungcan.2007.09.027] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2007] [Revised: 09/20/2007] [Accepted: 09/29/2007] [Indexed: 11/20/2022]
Abstract
The diagnosis, staging, and response assessment of mesothelioma pose unique challenges to radiologic imaging. No single, conventional imaging approach captures the information necessary to direct all aspects of patient management. Instead, the complexities of this unique disease demand the integration of elements cleverly adapted from different modalities. Imaging-based studies presented at the 8th International Conference of the International Mesothelioma Interest Group (IMIG) in October 2006 sought to further define the current practice and future potential of radiology for the mesothelioma patient. The imaging studies selected through a peer-review process for presentation at the 2006 IMIG Conference were intended to frame this research in the context of the unique imaging challenges presented by mesothelioma while stimulating dialogue on the future resolution of these challenges. This communication conveys the pitfalls and potential of pleural mesothelioma imaging based on work presented at the Conference. From diagnosis to response, PET/CT to molecular bioprobes, volumetric analysis to computerized tumor assessment, imaging promises to provide valuable insight for patients with mesothelioma and the physicians who treat them.
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Affiliation(s)
- Samuel G Armato
- Department of Radiology, The University of Chicago, 5841 S. Maryland Ave., MC 2026, Chicago, IL 60637, USA.
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Filpula D, Yang K, Basu A, Hassan R, Xiang L, Zhang Z, Wang M, Wang QC, Ho M, Beers R, Zhao H, Peng P, Zhou J, Li X, Petti G, Janjua A, Liu J, Wu D, Yu D, Zhang Z, Longley C, FitzGerald D, Kreitman RJ, Pastan I. Releasable PEGylation of Mesothelin Targeted Immunotoxin SS1P Achieves Single Dosage Complete Regression of a Human Carcinoma in Mice. Bioconjug Chem 2007; 18:773-84. [PMID: 17346030 DOI: 10.1021/bc060314x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Recombinant immunotoxins exhibit targeting and cytotoxic functions needed for cell-specific destruction. However, antitumor efficacy, safety, and pharmacokinetics of these therapeutics might be improved by further macromolecular engineering. SS1P is a recombinant anti-mesothelin immunotoxin in clinical trials in patients with mesothelin-expressing tumors. We have modified this immunotoxin using several PEGylation strategies employing releasable linkages between the protein and the PEG polymers, and observed superior performance of these bioconjugates when compared to similar PEG derivatives bearing permanent linkages to the polymers. PEGylated derivatives displayed markedly diminished cytotoxicity on cultured mesothelin-overexpressing A431-K5 cells; however, the releasable PEGylated immunotoxins exhibited increased antitumor activity in A431-K5 xenografts in mice, with a diminished animal toxicity. Most significantly, complete tumor regressions were achievable with single dose administration of the bioconjugates but not the native immunotoxin. Pharmacokinetic analysis of the releasable PEGylated derivatives in mice demonstrated an over 80-fold expansion of the area under the curve exposure of bioactive protein when compared to native immunotoxin. A correlation in degree of derivatization, release kinetics, and polymer size with potency was observed in vivo, whereas in vitro cytotoxicity was not predictive of efficacy in animal models. The potent antitumor efficacy of the releasable PEGylated mesothelin-targeted immunotoxins was not exhibited by similar untargeted PEG immunotoxins in this model. Since the bioconjugates can also exhibit the attributes of passive targeting via enhanced permeability and retention, this is the first demonstration of a pivotal role of active targeting for immunotoxin bioconjugate efficacy.
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Affiliation(s)
- David Filpula
- Enzon Pharmaceuticals, Incorporated, 20 Kingsbridge Road, Piscataway, New Jersey 08854, and Laboratory of Molecular Biology, National Cancer Institute, NIH, Bethesda, Maryland 20892, USA.
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Onda M, Willingham M, Nagata S, Bera TK, Beers R, Ho M, Hassan R, Kreitman RJ, Pastan I. New monoclonal antibodies to mesothelin useful for immunohistochemistry, fluorescence-activated cell sorting, Western blotting, and ELISA. Clin Cancer Res 2005; 11:5840-6. [PMID: 16115924 DOI: 10.1158/1078-0432.ccr-05-0578] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE Mesothelin is a cell surface protein that is highly expressed in some malignant tumors, and is a promising target for immunotherapy. Recent data suggests that mesothelin is an adhesive protein and may have a role in the metastases of ovarian cancer. Although a few monoclonal antibodies (MAb) to mesothelin have been produced, they have limitations for the study of expression of native mesothelin because of their low affinity or reactivity only with denatured mesothelin protein. We have produced novel MAbs to mesothelin to help study mesothelin function and to develop improved diagnosis and immunotherapy of mesothelin-expressing tumors. EXPERIMENTAL DESIGN Mesothelin-deficient mice were immunized with plasmid cDNA encoding mesothelin, and boosted with a mesothelin-rabbit IgG Fc fusion protein prior to cell fusion. Hybridomas were screened by an ELISA using plates coated with mesothelin-Fc protein. RESULTS Seventeen hybridomas producing anti-mesothelin antibodies were established and shown to react with two epitopes on mesothelin. One group reacts with the same epitope as the low affinity antibody K1 that was originally used to identify mesothelin. The other is a new group that reacts with a new epitope. One antibody from each group was chosen for further study and shown to react strongly on ELISA, on immunohistochemistry, and by fluorescence-activated cell sorting on living cells. CONCLUSION Our two newly established MAbs, MN and MB, have different and useful properties compared with current antibodies used for the detection of mesothelin by immunohistochemistry, fluorescence-activated cell sorting, ELISA, and Western blotting.
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Affiliation(s)
- Masanori Onda
- Laboratory of Molecular Biology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, Maryland 20892-4264, USA
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Abstract
Mesothelin is a differentiation antigen present on normal mesothelial cells and overexpressed in several human tumors, including mesothelioma and ovarian and pancreatic adenocarcinoma. The mesothelin gene encodes a precursor protein that is processed to yield the 40-kDa protein, mesothelin, attached to the cell membrane by a glycosylphosphatidyl inositol linkage and a 31-kDa shed fragment named megakaryocyte-potentiating factor. The biological function of mesothelin is not known. Mesothelin is a promising candidate for tumor-specific therapy, given its limited expression in normal tissues and high expression in several cancers. SS1(dsFv)PE38 is a recombinant anti-mesothelin immunotoxin that is undergoing clinical evaluation in patients with mesothelin-expressing tumors. There is evidence that mesothelin is an immunogenic protein and could be exploited as a therapeutic cancer vaccine. A soluble mesothelin variant has been identified and could be a useful tumor marker for malignant mesotheliomas.
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Affiliation(s)
- Raffit Hassan
- Laboratory of Molecular Biology, National Cancer Institute, NIH, Bethesda, Maryland, USA.
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28
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Abstract
INTRODUCTION The use of biological molecules, such as immunotoxins, as pharmaceuticals is limited by the presence and development of human antibodies to these agents. This immune response can cause significant inflammatory-related toxicities and can interfere with the efficacy of the biological agent. Therefore, a clinically applicable method to detect these human antibodies is needed for screening patients prior to enrollment and for monitoring patients during treatment. The SS1(dsFv)-PE38 immunotoxin currently in clinical trials is a hybrid molecule targeted against mesothelin-expressing cancer cells via the Fv portion of a murine antibody linked to the Pseudomonas exotoxin (PE), which can inhibit protein synthesis leading to cell death. The objective of this study was to determine if an enzyme-linked immunosorbent assay (ELISA)-based method could be used to detect human anti-SS1(dsFv)-PE38 antibodies in patient serum. METHODS Human antibodies to the immunotoxin in serially diluted serum specimens were captured on immunotoxin-coated ELISA plates, and detected using a secondary goat antihuman antibody linked to biotin in combination with horseradish peroxidase linked to avidin D (HRP-Avidin). The color was developed with tetramethyl benzidine (TMB). Curves of optical density (OD(630)) versus dilution for 44 serum specimens were compared with positive and negative control serum specimens to classify the serum as positive or negative for anti-immunotoxin antibodies. RESULTS Ten out of the 40 patients screened were positive for anti-immunotoxin antibodies. Repeated testing of seven samples produced the same results in two independent experiments. The first two patients treated with the immunotoxin developed anti-immunotoxin antibodies during treatment. The results were in perfect concordance with a tissue culture-based neutralization assay performed by an independent laboratory. DISCUSSION An ELISA-based strategy using an immunotoxin to capture human anti-immunotoxin antibodies provides a consistently accurate technology for screening and monitoring patient serum specimens in clinical trials.
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Affiliation(s)
- Doris M Benbrook
- Department of Obstetrics and Gynecology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73190, USA.
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Yamashita Y, Yokoyama M, Kobayashi E, Takai S, Hino O. Mapping and determination of the cDNA sequence of the Erc gene preferentially expressed in renal cell carcinoma in the Tsc2 gene mutant (Eker) rat model. Biochem Biophys Res Commun 2000; 275:134-40. [PMID: 10944454 DOI: 10.1006/bbrc.2000.3280] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The Eker rat develops hereditary renal carcinomas (RCs) due to two hit mutations of the tumor suppressor gene, Tsc2. We previously identified using representational difference analysis (RDA), four genes that were expressed more abundantly in an Eker rat RC cell line than in normal kidney tissue. One gene, Erc (expressed in renal carcinoma) showed sequence homology to the mouse and human megakaryocyte potentiating factor (MPF)/mesothelin gene. The present study determines the full sequence of the cDNA and the exon-intron structure of the rat Erc gene and maps its locus in the chromosome by fluorescence in situ hybridization. Rat Erc and its human homologue were localized in chromosomes 10q12-21 and 16p13.3, respectively, both of which coincided with the locus of the Tsc2/TSC gene. We also found that Erc was expressed at higher levels in primary RCs compared with the normal kidney of the Eker rat. Erc may be related to carcinogenesis in the Tsc2 gene mutant (Eker) rat model.
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MESH Headings
- Amino Acid Sequence
- Animals
- Base Sequence
- Carcinoma, Renal Cell/genetics
- Chromosomes, Human, Pair 16/genetics
- Cloning, Molecular
- Disease Models, Animal
- Exons/genetics
- GPI-Linked Proteins
- Gene Expression Regulation, Neoplastic/genetics
- Humans
- In Situ Hybridization, Fluorescence
- Introns/genetics
- Kidney Neoplasms/genetics
- Membrane Glycoproteins/chemistry
- Mesothelin
- Molecular Sequence Data
- Mutation/genetics
- Oncogene Proteins/chemistry
- Oncogene Proteins/genetics
- Physical Chromosome Mapping
- RNA, Messenger/metabolism
- Rats
- Rats, Inbred Strains
- Repressor Proteins/genetics
- Sequence Alignment
- Tuberous Sclerosis Complex 2 Protein
- Tumor Cells, Cultured
- Tumor Suppressor Proteins
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Affiliation(s)
- Y Yamashita
- Department of Experimental Pathology, Cancer Institute, Tokyo, 170-8455, Japan
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Hassan R, Viner JL, Wang QC, Margulies I, Kreitman RJ, Pastan I. Anti-tumor activity of K1-LysPE38QQR, an immunotoxin targeting mesothelin, a cell-surface antigen overexpressed in ovarian cancer and malignant mesothelioma. J Immunother 2000; 23:473-9. [PMID: 10916757 DOI: 10.1097/00002371-200007000-00011] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Mesothelin, a differentiation antigen, is a 40-kD glycosylphosphatidylinositol-linked cell-surface glycoprotein, that is present on the surface of normal mesothelium and is overexpressed in many patients with epithelial ovarian cancer and malignant mesotheliomas. Monoclonal antibody K1 is a murine immunoglobulin G1 that recognizes mesothelin. LysPE38QQR is a truncated form of Pseudomonas exotoxin that lacks the cell-binding domain, but retains the translocation and adenosine diphosphate-ribosylation domains. It has a single lysine residue near the amino terminus that is available for conjugation to antibodies. To prevent chemical conjugation of the antibody to lysine residues at the C-terminus of Pseudomonas exotoxin, the two lysine residues at positions 590 and 606 were mutated to glutamine, and the lysine residue at position 613 was mutated to arginine. Monoclonal antibody K1 was chemically conjugated with LysPE38QQR, by modifying the antibody with sulfosuccinimidyl-4-(N-maleimidomethyl)cyclohexane-1-carboxylate and coupling it with SPDP N-succinimidyl 3-(2-pyridyldithio)propionate-modified LysPE38QQR. The resulting immunotoxin K1-LysPE38QQR was highly toxic to A431-K5 cells (a human epidermoid carcinoma cell line transfected with a mesothelin expression plasmid) with a half-maximal inhibitory concentration of 3-6 ng/mL. The immunotoxin had negligible activity against A431 cells, which do not express mesothelin (median inhibitory concentration > 100 ng/mL). This immunotoxin also caused complete regression of tumors in nude mice that received xenografts of mesothelin-positive human carcinomas. These results show that immunotoxins directed against mesothelin are a therapeutic option that merits further investigation for the treatment of ovarian cancer and malignant mesotheliomas.
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Affiliation(s)
- R Hassan
- Laboratory of Molecular Biology, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, USA
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