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Li M, Liu D, Lee D, Cheng Y, Baumhover NJ, Marks BM, Sagastume EA, Ballas ZK, Johnson FL, Morris ZS, Schultz MK. Targeted Alpha-Particle Radiotherapy and Immune Checkpoint Inhibitors Induces Cooperative Inhibition on Tumor Growth of Malignant Melanoma. Cancers (Basel) 2021; 13:cancers13153676. [PMID: 34359580 PMCID: PMC8345035 DOI: 10.3390/cancers13153676] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Revised: 07/13/2021] [Accepted: 07/16/2021] [Indexed: 12/23/2022] Open
Abstract
Simple Summary Radiation therapy and immune checkpoint inhibitors (ICIs) have been demonstrated to cooperatively activate adaptive anti-tumor immunity with curative potential in preclinical models of melanoma. Receptor-targeted radionuclide therapy can be systemically injected to selectively deliver ionizing radiation to tumor sites throughout the body, potentially rendering all tumor sites more susceptible to anti-tumor immune response. In this study, we demonstrated the feasibility of delivering alpha-particle radiation to murine melanoma tumors using a 212Pb radiolabeled peptide [212Pb]VMT01 that targets the melanocortin 1 receptor (MC1R). Our data showed anti-tumor cooperation between [212Pb]VMT01 and ICIs in melanoma, mediated by induction of tumor-specific immunity. The immunogenicity of [212Pb]VMT01 in melanoma was also evidenced by enhanced tumor infiltrating lymphocytes and tumor vaccination assays. Abstract Radiotherapy can facilitate the immune recognition of immunologically “cold” tumors and enhance the efficacy of anti-PD-1 and anti-CTLA-4 immune checkpoint inhibitors (ICIs) in melanoma. Systemic administration of receptor-targeted radionuclide therapy has the potential to selectively deliver radionuclides to multiple tumors throughout the body in metastatic settings. By triggering immunologic cell death and increasing the immune susceptibility of surviving tumor cells in these locations, targeted radionuclide therapies may overcome resistance to ICIs and render immunologically “cold” tumors throughout the body responsive to ICIs and immunologically “hot”. Here, we show the anti-tumor cooperation of targeted α-particle radionuclide therapy (α-TRT) and ICIs in preclinical models of melanoma. Melanocortin 1 receptor (MC1R)-targeted radiopeptide [212Pb]VMT01 was employed to deliver α-radiation to melanoma tumors in mice. A single injection of 4.1 MBq [212Pb]VMT01 significantly slowed the tumor growth of B16-F10 melanoma and the combination of [212Pb]VMT01 and ICIs induced a cooperative anti-tumor effect leading to 43% complete tumor response with no sign of malignancy on autopsy. Animals with complete response developed anti-tumor immunity to reject further tumor inoculations. This therapeutic cooperation was completely abolished in RAG1 KO mice, which are deficient in T-cell maturation. In addition, the anti-tumor cooperation was compromised when fractionated [212Pb]VMT01 was used in the combination. We also demonstrated that [212Pb]VMT01 induced immunogenic cell death in tumor vaccination assays and in vitro exposure to [212Pb]VMT01 sensitized immunotolerant melanoma to ICIs treatment in vivo. Enhanced tumor infiltrating CD3+, CD4+, CD8+ lymphocytes were observed following injection of 1.4 MBq [212Pb]VMT01. Overall, we demonstrated anti-tumor cooperation between α-TRT and ICIs in melanoma that is mediated by tumor specific immunity.
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Affiliation(s)
- Mengshi Li
- Viewpoint Molecular Targeting, Inc., Coralville, IA 52241, USA; (M.L.); (D.L.); (N.J.B.); (B.M.M.); (E.A.S.); (F.L.J.)
- Department of Radiology, University of Iowa, Iowa City, IA 52242, USA;
| | - Dijie Liu
- Viewpoint Molecular Targeting, Inc., Coralville, IA 52241, USA; (M.L.); (D.L.); (N.J.B.); (B.M.M.); (E.A.S.); (F.L.J.)
- Department of Radiology, University of Iowa, Iowa City, IA 52242, USA;
| | - Dongyoul Lee
- Department of Radiology, University of Iowa, Iowa City, IA 52242, USA;
| | - Yinwen Cheng
- Interdisciplinary Graduate Program in Human Toxicology, University of Iowa, Iowa City, IA 52242, USA;
- Department of Pathology, University of Iowa, Iowa City, IA 52242, USA
| | - Nicholas J. Baumhover
- Viewpoint Molecular Targeting, Inc., Coralville, IA 52241, USA; (M.L.); (D.L.); (N.J.B.); (B.M.M.); (E.A.S.); (F.L.J.)
- Department of Radiology, University of Iowa, Iowa City, IA 52242, USA;
| | - Brenna M. Marks
- Viewpoint Molecular Targeting, Inc., Coralville, IA 52241, USA; (M.L.); (D.L.); (N.J.B.); (B.M.M.); (E.A.S.); (F.L.J.)
| | - Edwin A. Sagastume
- Viewpoint Molecular Targeting, Inc., Coralville, IA 52241, USA; (M.L.); (D.L.); (N.J.B.); (B.M.M.); (E.A.S.); (F.L.J.)
| | - Zuhair K. Ballas
- Department of Internal Medicine, University of Iowa, Iowa City, IA 52242, USA;
| | - Frances L. Johnson
- Viewpoint Molecular Targeting, Inc., Coralville, IA 52241, USA; (M.L.); (D.L.); (N.J.B.); (B.M.M.); (E.A.S.); (F.L.J.)
- Department of Internal Medicine, University of Iowa, Iowa City, IA 52242, USA;
| | - Zachary S. Morris
- Department of Human Oncology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI 53705, USA;
| | - Michael K. Schultz
- Viewpoint Molecular Targeting, Inc., Coralville, IA 52241, USA; (M.L.); (D.L.); (N.J.B.); (B.M.M.); (E.A.S.); (F.L.J.)
- Department of Radiology, University of Iowa, Iowa City, IA 52242, USA;
- Interdisciplinary Graduate Program in Human Toxicology, University of Iowa, Iowa City, IA 52242, USA;
- Department of Pediatrics, University of Iowa, Iowa City, IA 52242, USA
- Department of Chemistry, University of Iowa, Iowa City, IA 52242, USA
- Correspondence: ; Tel.: +1-(865)-356-1861
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Yong KJ, Milenic DE, Baidoo KE, Brechbiel MW. Impact of α-targeted radiation therapy on gene expression in a pre-clinical model for disseminated peritoneal disease when combined with paclitaxel. PLoS One 2014; 9:e108511. [PMID: 25268703 PMCID: PMC4182481 DOI: 10.1371/journal.pone.0108511] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2014] [Accepted: 08/31/2014] [Indexed: 11/19/2022] Open
Abstract
To better understand the molecular basis of the enhanced cell killing effected by the combined modality of paclitaxel and ²¹²Pb-trastuzumab (Pac/²¹²Pb-trastuzumab), gene expression in LS-174T i.p. xenografts was investigated 24 h after treatment. Employing a real time quantitative PCR array (qRT-PCR array), 84 DNA damage response genes were quantified. Differentially expressed genes following therapy with Pac/²¹²Pb-trastuzumab included those involved in apoptosis (BRCA1, CIDEA, GADD45α, GADD45γ, GML, IP6K3, PCBP4, PPP1R15A, RAD21, and p73), cell cycle (BRCA1, CHK1, CHK2, GADD45α, GML, GTSE1, NBN, PCBP4, PPP1R15A, RAD9A, and SESN1), and damaged DNA repair (ATRX, BTG2, EXO1, FEN1, IGHMBP2, OGG1, MSH2, MUTYH, NBN, PRKDC, RAD21, and p73). This report demonstrates that the increased stressful growth arrest conditions induced by the Pac/²¹²Pb-trastuzumab treatment suppresses cell proliferation through the regulation of genes which are involved in apoptosis and damaged DNA repair including single and double strand DNA breaks. Furthermore, the study demonstrates that ²¹²Pb-trastuzumab potentiation of cell killing efficacy results from the perturbation of genes related to the mitotic spindle checkpoint and BASC (BRCA1-associated genome surveillance complex), suggesting cross-talk between DNA damage repair and the spindle damage response.
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MESH Headings
- Animals
- Antibodies, Monoclonal, Humanized/pharmacology
- Antineoplastic Agents/pharmacology
- Apoptosis Regulatory Proteins/genetics
- Apoptosis Regulatory Proteins/metabolism
- Cell Cycle Proteins/genetics
- Cell Cycle Proteins/metabolism
- Colonic Neoplasms/genetics
- Colonic Neoplasms/metabolism
- Colonic Neoplasms/pathology
- Colonic Neoplasms/therapy
- Combined Modality Therapy
- DNA Breaks, Double-Stranded/drug effects
- DNA Breaks, Double-Stranded/radiation effects
- DNA Breaks, Single-Stranded/drug effects
- DNA Breaks, Single-Stranded/radiation effects
- DNA Repair Enzymes/genetics
- DNA Repair Enzymes/metabolism
- Drug Evaluation, Preclinical
- Female
- Gene Expression Profiling
- Gene Expression Regulation, Neoplastic
- Humans
- Injections, Intraperitoneal
- Lead Radioisotopes
- Mice
- Mice, Nude
- Oligonucleotide Array Sequence Analysis
- Paclitaxel/pharmacology
- Peritoneal Neoplasms/genetics
- Peritoneal Neoplasms/metabolism
- Peritoneal Neoplasms/pathology
- Peritoneal Neoplasms/therapy
- Radioimmunotherapy/methods
- Trastuzumab
- Xenograft Model Antitumor Assays
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Affiliation(s)
- Kwon Joong Yong
- Radioimmune & Inorganic Chemistry Section, Radiation Oncology Branch, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Diane E. Milenic
- Radioimmune & Inorganic Chemistry Section, Radiation Oncology Branch, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Kwamena E. Baidoo
- Radioimmune & Inorganic Chemistry Section, Radiation Oncology Branch, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Martin W. Brechbiel
- Radioimmune & Inorganic Chemistry Section, Radiation Oncology Branch, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
- * E-mail:
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Chauhan V, Howland M, Wilkins R. Identification of gene-based responses in human blood cells exposed to alpha particle radiation. BMC Med Genomics 2014; 7:43. [PMID: 25017500 PMCID: PMC4128605 DOI: 10.1186/1755-8794-7-43] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Accepted: 07/07/2014] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND The threat of a terrorist-precipitated nuclear event places humans at danger for radiological exposures. Isotopes which emit alpha (α)-particle radiation pose the highest risk. Currently, gene expression signatures are being developed for radiation biodosimetry and triage with respect to ionizing photon radiation. This study was designed to determine if similar gene expression profiles are obtained after exposures involving α-particles. METHODS Peripheral blood mononuclear cells (PBMCs) were used to identify sensitive and robust gene-based biomarkers of α-particle radiation exposure. Cells were isolated from healthy individuals and were irradiated at doses ranging from 0-1.5 Gy. Microarray technology was employed to identify transcripts that were differentially expressed relative to unirradiated cells 24 hours post-exposure. Statistical analysis identified modulated genes at each of the individual doses. RESULTS Twenty-nine genes were common to all doses with expression levels ranging from 2-10 fold relative to control treatment group. This subset of genes was further assessed in independent complete white blood cell (WBC) populations exposed to either α-particles or X-rays using quantitative real-time PCR. This 29 gene panel was responsive in the α-particle exposed WBCs and was shown to exhibit differential fold-changes compared to X-irradiated cells, though no α-particle specific transcripts were identified. CONCLUSION Current gene panels for photon radiation may also be applicable for use in α-particle radiation biodosimetry.
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Affiliation(s)
- Vinita Chauhan
- Consumer and Clinical Radiation Protection Bureau, Healthy Environment and Consumer Safety Branch, Health Canada, 775 Brookfield Road, PL 6303B, Ottawa, ON K1A 1C1, Canada.
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Choi VWY, Yu KN. Embryos of the zebrafish Danio rerio in studies of non-targeted effects of ionizing radiation. Cancer Lett 2013; 356:91-104. [PMID: 24176822 DOI: 10.1016/j.canlet.2013.10.020] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2013] [Revised: 10/16/2013] [Accepted: 10/22/2013] [Indexed: 01/17/2023]
Abstract
The use of embryos of the zebrafish Danio rerio as an in vivo tumor model for studying non-targeted effects of ionizing radiation was reviewed. The zebrafish embryo is an animal model, which enables convenient studies on non-targeted effects of both high-linear-energy-transfer (LET) and low-LET radiation by making use of both broad-beam and microbeam radiation. Zebrafish is also a convenient embryo model for studying radiobiological effects of ionizing radiation on tumors. The embryonic origin of tumors has been gaining ground in the past decades, and efforts to fight cancer from the perspective of developmental biology are underway. Evidence for the involvement of radiation-induced genomic instability (RIGI) and the radiation-induced bystander effect (RIBE) in zebrafish embryos were subsequently given. The results of RIGI were obtained for the irradiation of all two-cell stage cells, as well as 1.5 hpf zebrafish embryos by microbeam protons and broad-beam alpha particles, respectively. In contrast, the RIBE was observed through the radioadaptive response (RAR), which was developed against a subsequent challenging dose that was applied at 10 hpf when <0.2% and <0.3% of the cells of 5 hpf zebrafish embryos were exposed to a priming dose, which was provided by microbeam protons and broad-beam alpha particles, respectively. Finally, a perspective on the field, the need for future studies and the significance of such studies were discussed.
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Affiliation(s)
- V W Y Choi
- Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong, Hong Kong
| | - K N Yu
- Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong, Hong Kong; State Key Laboratory in Marine Pollution, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong, Hong Kong.
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Yong KJ, Milenic DE, Baidoo KE, Kim YS, Brechbiel MW. Gene expression profiling upon (212) Pb-TCMC-trastuzumab treatment in the LS-174T i.p. xenograft model. Cancer Med 2013; 2:646-53. [PMID: 24403230 PMCID: PMC3892796 DOI: 10.1002/cam4.132] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2013] [Revised: 07/30/2013] [Accepted: 08/14/2013] [Indexed: 02/03/2023] Open
Abstract
Recent studies have demonstrated that therapy with (212) Pb-TCMC-trastuzumab resulted in (1) induction of apoptosis, (2) G2/M arrest, and (3) blockage of double-strand DNA damage repair in LS-174T i.p. (intraperitoneal) xenografts. To further understand the molecular basis of the cell killing efficacy of (212) Pb-TCMC-trastuzumab, gene expression profiling was performed with LS-174T xenografts 24 h after exposure to (212) Pb-TCMC-trastuzumab. DNA damage response genes (84) were screened using a quantitative real-time polymerase chain reaction array (qRT-PCR array). Differentially regulated genes were identified following exposure to (212) Pb-TCMC-trastuzumab. These included genes involved in apoptosis (ABL, GADD45α, GADD45γ, PCBP4, and p73), cell cycle (ATM, DDIT3, GADD45α, GTSE1, MKK6, PCBP4, and SESN1), and damaged DNA binding (DDB) and repair (ATM and BTG2). The stressful growth arrest conditions provoked by (212) Pb-TCMC-trastuzumab were found to induce genes involved in apoptosis and cell cycle arrest in the G2/M phase. The expression of genes involved in DDB and single-strand DNA breaks was also enhanced by (212) Pb-TCMC-trastuzumab while no modulation of genes involved in double-strand break repair was apparent. Furthermore, the p73/GADD45 signaling pathway mediated by p38 kinase signaling may be involved in the cellular response, as evidenced by the enhanced expression of genes and proteins of this pathway. These results further support the previously described cell killing mechanism by (212) Pb-TCMC-trastuzumab in the same LS-174T i.p. xenograft. Insight into these mechanisms could lead to improved strategies for rational application of radioimmunotherapy using α-particle emitters.
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Affiliation(s)
- Kwon J Yong
- Radioimmune and Inorganic Chemistry Section, Radiation Oncology Branch, National Cancer Institute, National Institutes of HealthBethesda, Maryland
| | - Diane E Milenic
- Radioimmune and Inorganic Chemistry Section, Radiation Oncology Branch, National Cancer Institute, National Institutes of HealthBethesda, Maryland
| | - Kwamena E Baidoo
- Radioimmune and Inorganic Chemistry Section, Radiation Oncology Branch, National Cancer Institute, National Institutes of HealthBethesda, Maryland
| | - Young-Seung Kim
- Radioimmune and Inorganic Chemistry Section, Radiation Oncology Branch, National Cancer Institute, National Institutes of HealthBethesda, Maryland
| | - Martin W Brechbiel
- Radioimmune and Inorganic Chemistry Section, Radiation Oncology Branch, National Cancer Institute, National Institutes of HealthBethesda, Maryland
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Chauhan V, Howland M. Genomic profiling of a human leukemic monocytic cell-line (THP-1) exposed to alpha particle radiation. ScientificWorldJournal 2012; 2012:205038. [PMID: 23097634 PMCID: PMC3477555 DOI: 10.1100/2012/205038] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2012] [Accepted: 09/02/2012] [Indexed: 11/26/2022] Open
Abstract
This study examined alpha (α-) particle radiation effects on global changes in gene expression in human leukemic monocytic cells (THP-1) for the purposes of mining for candidate biomarkers that could be used for the development of a biological assessment tool. THP-1 cells were exposed to α-particle radiation at a dose range of 0 to 1.5 Gy. Twenty-four hours and three days after exposure gene expression was monitored using microarray technology. A total of 16 genes were dose responsive and classified as early onset due to their expression 24 h after exposure. Forty-eight transcripts were dose responsive and classified as late-onset as they were expressed 72 h after exposure. Among these genes, 6 genes were time and dose responsive and validated further using alternate technology. These transcripts were upregulated and associated with biological processes related to immune function, organelle stability and cell signalling/communication. This panel of genes merits further validation to determine if they are strong candidate biomarkers indicative of α-particle exposure.
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Affiliation(s)
- Vinita Chauhan
- Consumer and Clinical Radiation Protection Bureau, Health Canada, Healthy Environment and Consumer Safety Branch, Ottawa, ON, Canada K1A 0K9. vinita
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Chauhan V, Howland M, Wilkins R. A comparitive assessement of cytokine expression in human-derived cell lines exposed to alpha particles and X-rays. ScientificWorldJournal 2012; 2012:609295. [PMID: 22619631 PMCID: PMC3347887 DOI: 10.1100/2012/609295] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2011] [Accepted: 12/05/2011] [Indexed: 12/25/2022] Open
Abstract
Alpha- (α-) particle radiation exposure has been linked to the development of lung cancer and has been identified as a radiation type likely to be employed in radiological dispersal devices. Currently, there exists a knowledge gap concerning cytokine modulations associated with exposure to α-particles. Bio-plex technology was employed to investigate changes in proinflammatory cytokines in two human-derived cell lines. Cells were irradiated at a dose of 1.5 Gy to either α-particles or X-rays at equivalent dose rates. The two cell lines exhibited a unique pattern of cytokine expression and the response varied with radiation type. Of the 27 cytokines assessed, only vascular endothelin growth factor (VEGF) was observed to be modulated in both cell lines solely after α-particle exposure, and the expression of VEGF was shown to be dose responsive. These results suggest that certain proinflammatory cytokines may be involved in the biological effects related to α- particle exposure and the responses are cell type and radiation type specific.
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Affiliation(s)
- Vinita Chauhan
- Consumer and Clinical Radiation Protection Bureau, Health Canada, Ottawa, ON, Canada.
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Chauhan V, Howland M, Wilkins R. Effects of α-Particle Radiation on MicroRNA Responses in Human Cell-Lines. Open Biochem J 2012; 6:16-22. [PMID: 22481983 PMCID: PMC3314867 DOI: 10.2174/1874091x01206010016] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2011] [Revised: 01/21/2012] [Accepted: 02/14/2012] [Indexed: 11/22/2022] Open
Abstract
A variety of alpha (α)-particle emitters are found ubiquitously in the environment, in commercial/therapeutic prod-ucts and are a potential threat in the form of a radiological dispersal device. Our understanding of the biological mechanisms and long-term health effects resulting from α-particle exposure is limited. Exposure to radiation induces modulations of gene networks, possibly through microRNAs (miRNAs), which could be targets for studying biological effects. In this study, changes in miRNA expression patterns after 0.5 Gy, 1.0 Gy and 1.5 Gy of α-particle radiation at a low dose-rate of exposure in three human cell-lines (A549, THP-1 and HFL) were investigated. The screening of 1,145 miRNAs across three human cell-lines resulted in unique, cell-specific responses with no overlap in miRNA expression observed in the three cell-lines. Prediction analysis suggests these α-particle induced miRNA mapped to target genes related to ribosomal assembly, lung carcinoma development, cell communication and keratin sulfate biosynthesis. Taken together, these results suggest that exposure to α-particle radiation results in cell-type specific responses in gene network regulatory processes.
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Affiliation(s)
- Vinita Chauhan
- Consumer and Clinical Radiation Protection Bureau, Health Canada, Ottawa, Ontario, K1A 0K9 Canada
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Chauhan V, Howland M, Kutzner B, McNamee JP, Bellier PV, Wilkins RC. Biological effects of alpha particle radiation exposure on human monocytic cells. Int J Hyg Environ Health 2011; 215:339-44. [PMID: 22153871 DOI: 10.1016/j.ijheh.2011.11.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2011] [Revised: 10/06/2011] [Accepted: 11/08/2011] [Indexed: 01/18/2023]
Abstract
Radon ((222)Rn) gas produces decay progeny that emits high energy alpha (α)-particles. Epidemiological studies have shown that exposure to (222)Rn is linked with elevated risk of developing lung cancer, however clear mechanisms leading to such effects have not been delineated. Cytokines play a critical role in inflammation and their dysregulated production often contributes to disease pathogenesis. In this study, Bio-plex multiplex technology was employed to investigate modulations of 27 pro-inflammatory cytokines following exposure of human monocytic cells to 1.5 Gy of α-particle radiation. Concurrently, DNA damage was assessed by examining the formation of phosphorylated H2A histone family X (γ-H2AX) sites. Of the 27 cytokines assessed, 4 cytokines were shown to be statistically downregulated by ∼2 fold relative to the untreated controls and included the interleukin (IL) family of proteins (IL-2, IL-15 and IL-17) and macrophage inflammatory protein 1 beta (MIP-1b). Interferon-inducible protein-12 (IP-12), vascular endothelial growth factor and regulated on activation normal T cell expressed and secreted (RANTES) were shown to be high expressors and upregulated. Cells irradiated with α-particles ranging from 0.27 to 2.14 Gy showed statistically significant, dose-dependant increases in γ-H2AX formation. These data suggest that α-particle radiation causes dysregulation in the production of a number of pro-inflammatory cytokines and results in significant DNA damage.
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Affiliation(s)
- Vinita Chauhan
- Consumer and Clinical Radiation Protection Bureau, Health Canada, ON, Canada K1A 0K9. Vinita
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