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Kassis AI, Wu Q, Joy MP, Balagurumoorthy P, Loda M, Evan C, Petrozziello G, Kantoff PW, Adelstein SJ. Abstract LB-69: Novel WBC gene expression assay for prostate cancer detection. Cancer Res 2013. [DOI: 10.1158/1538-7445.am2013-lb-69] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
In recent studies, we showed that several oncogenes and cancer-associated genes and proteins are differentially expressed in phagocytic WBCs of tumor-bearing mice (colon, lung, melanoma, and prostate), compared to non-phagocytic WBCs from the same mice as well as to phagocytic WBCs obtained from non-tumor-bearing mice. Prompted by the translational potential of these findings, we carried out whole genome microarray analysis of total RNA samples isolated from peripheral blood phagocytic (macrophages and neutrophils) and nonphagocytic (T cells) WBCs of prostate cancer patients (n = 58) and blood donors (n = 36). Comparison of the genomic expression profiles of macrophages vs. T cells or neutrophils vs. T cells of these patients to those identified in blood donors revealed the presence of gene signatures that are unique to the patient population. These differentially expressed genes were used to generate receiver operating characteristic curves. The area under the curve was 1.000 for macrophages and 0.980 for neutrophils, indicating the high accuracy of the assay. While the PSA cutoff of 4 ng/mL failed to identify 14 of the 58 patients, the assay reported herein correctly identified 57 out of the 58 patients and all 36 controls (sensitivity = 0.983; specificity = 1.000) when macrophages were used; with neutrophils, there were 7 false negatives (sensitivity = 0.879; Specificity = 1.000). These promising results suggest that the approach lays the foundation for a next generation diagnostic blood test for prostate-cancer.
Citation Format: Amin I. Kassis, Qi Wu, Maliackal Poulo Joy, Pichumani Balagurumoorthy, Massimo Loda, Carolyn Evan, Gillian Petrozziello, Philip W. Kantoff, S. James Adelstein. Novel WBC gene expression assay for prostate cancer detection. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr LB-69. doi:10.1158/1538-7445.AM2013-LB-69
Note: This abstract was not presented at the AACR Annual Meeting 2013 because the presenter was unable to attend.
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Affiliation(s)
| | - Qi Wu
- Harvard Medical School, Boston, MA
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Balagurumoorthy P, Xu X, Wang K, Adelstein SJ, Kassis AI. Effect of distance between decaying (125)I and DNA on Auger-electron induced double-strand break yield. Int J Radiat Biol 2012; 88:998-1008. [PMID: 22732063 DOI: 10.3109/09553002.2012.706360] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
PURPOSE To determine the possible effects of (125)I-to-DNA distance on the magnitude and mechanism of Auger-electron induced-double-strand break (DSB) production. MATERIALS AND METHODS We have synthesized a series of (125)I-labeled Hoechst (H) derivatives ((125)IE-H, (125)IB-H, (125)I-C(8)-H and (125)I-C(12)-H). While all four molecules share a common DNA minor groove binding bis-benzimidazole motif, they are designed to position (125)I at varying distances from the DNA helix. Each Hoechst derivative was incubated at 4°C in phosphate buffered saline (PBS) together with supercoiled (SC) (3)H-pUC19 plasmid DNA (ratio 3:1) ± the •OH scavenger dimethyl sulfoxide (DMSO) (0.2 M). Aliquots were analyzed on agarose gels over time and DSB yields per decay of (125)I atom were determined. Docking of the iodinated compounds on a DNA molecule was carried out to determine the distance between the iodine atom and the central axis of DNA. RESULTS In the absence of DMSO, the results show that the DSB yields decrease monotonically as the (125)I atom is distanced - by 10.5 Å to 13.9 Å - from the DNA helix ((125)IEH: 0.52 ± 0.01; (125)IB-H: 0.24 ± 0.03; (125)I-C(8)-H: 0.18 ± 0.02; (125)I-C(12)-H: 0.10 ± 0.00). In the presence of DMSO, DSB yields for (125)IEH (0.49 ± 0.02) and (125)IB-H (0.26 ± 0.04) remain largely unchanged indicating that DSB are entirely produced by direct effects. Strikingly, (125)I-C(8)-H or (125)I-C(12)-H, did not produce detectable DSB in the presence of DMSO under similar conditions suggesting when (125)I atom is positioned > 12 Å from the DNA, DSB are entirely produced by indirect effects. CONCLUSION These results suggest that at a critical distance between the (125)I atom and the DNA helix, DSB production switches from an 'all' direct to an 'all' indirect mechanism, the latter situation being comparable to the decay of (125)I free in solution. These experimental findings were correlated with theoretical expectations based on microdosimetry.
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Abstract
The value of pediatric nuclear medicine is well established. Pediatric patients are referred to nuclear medicine from nearly all pediatric specialties including urology, oncology, cardiology, gastroenterology, and orthopedics. Radiation exposure is associated with a potential, small, risk of inducing cancer in the patient later in life and is higher in younger patients. Recently, there has been enhanced interest in exposure to radiation from medical imaging. Thus, it is incumbent on practitioners of pediatric nuclear medicine to have an understanding of dosimetry and radiation risk to communicate effectively with their patients and their families. This article reviews radiation dosimetry for radiopharmaceuticals and also CT given the recent proliferation of PET/CT and SPECT/CT. It also describes the scientific basis for radiation risk estimation in the context of pediatric nuclear medicine. Approaches for effective communication of risk to patients' families are discussed. Lastly, radiation dose reduction in pediatric nuclear medicine is explicated.
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Affiliation(s)
- Frederic H Fahey
- Division of Nuclear Medicine and Molecular Imaging, Department of Radiology, Children's Hospital Boston, Boston, Massachusetts 02115, USA.
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Mamlouk O, Balagurumoorthy P, Wang K, Adelstein SJ, Kassis AI. Bystander effect in tumor cells produced by Iodine-125 labeled human lymphocytes. Int J Radiat Biol 2012; 88:1019-27. [PMID: 22712702 DOI: 10.3109/09553002.2012.702297] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
PURPOSE To investigate the ability of human lymphocytes labeled with DNA-incorporated (125)I to exert an inhibitory (antiproliferative) bystander effect on co-cultured human colon adenocarcinoma LS174T cells in vitro. MATERIALS AND METHODS Human peripheral blood lymphocytes were stimulated to synthesize DNA in the presence of phytohemagglutinin (PHA) and labeled with 5-[(125)I]iodo-2'-deoxyuridine. Human colon adenocarcinoma LS174T cells were co-cultured with the (125)I-labeled lymphocytes in various ratios for 5 days and the proliferation of the LS174T cells was assessed. Further, the supernatant media from these co-cultures were: (i) Transferred to LS174T cells and their proliferation measured after 5 days, (ii) used to assess the clonogenic survival of LS174T cells, and (iii) screened for factors that suppress growth. RESULTS A significant reduction in the proliferation of LS174T cells was observed when co-cultured either with (125)I-labeled lymphocytes (56 ± 3.5%) or the supernatant media (52.5 ± 1.3%) obtained from these co-cultures. Clonogenic survival of LS174T cells grown in the supernatant media corroborated the decrease in tumor cell growth. CONCLUSION The observed reduction in the proliferation of LS174T cells in presence of (125)I-labeled lymphocytes or media obtained from such co-cultures can be attributed to an inhibitory (antiproliferative) bystander effect, probably mediated by factor(s) released from the dying (125)I-labeled lymphocytes.
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Affiliation(s)
- Omar Mamlouk
- Department of Radiology, Harvard Medical School, Boston, Massachusetts 02115, USA
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Adelstein SJ, Bernert BR, Hill HAO. Bert Lester Vallee: A lasting legacy. J Inorg Biochem 2012; 111:100-3. [DOI: 10.1016/j.jinorgbio.2012.01.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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Yang Y, Wang K, Li W, Adelstein SJ, Kassis AI. Human placental alkaline phosphatase-mediated hydrolysis correlates tightly with the electrostatic contribution from tail group. Chem Biol Drug Des 2011; 78:923-31. [PMID: 21910833 DOI: 10.1111/j.1747-0285.2011.01238.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Human placental alkaline phosphatase has been identified as a hydrolase that is significantly overexpressed on the surface of various solid tumor cells, and is therefore a suitable prodrug design target for non-invasive cancer imaging and therapy. Structure-based prediction of enzymatic activities is essential for rational prodrug design. We have been probing the catalytic proficiency--(k(cat) /K(M) )/k(w)--of placental alkaline phosphatase toward several widely diverse substrate structures experimentally and correlating these results to in silico predictions that are based on the free energy estimates obtained from docking of each substrate structure with placental alkaline phosphatase. We have found that electrostatic contribution from the tail group is the most crucial factor to determine the catalytic efficiencies of the substrates. The electrostatic contribution and the total binding energy of the tail group are well correlated with catalytic efficiencies (R² = 0.79 and 0.89, respectively). However, hydrophobic contribution from the tail group does not correlate with the catalytic efficiencies (negative correlation, R² = 0.27). This supports the prior hypothesis stating that alkaline phosphatase-mediated differential hydrolysis of its substrates is attributable to the differential interactions with the tail group, determined by the electrostatic contributions from the non-bridging oxygen atoms. Calculation of the electrostatic potentials within the active site of human placental alkaline phosphatase also suggests that the local positive electrostatic environment may account for its capability to distinguish various substrates. Our study is likely to have immediate implications in the design of prodrugs against human placental alkaline phosphatase and other esterases overexpressed by human tumor cells.
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Affiliation(s)
- Yongliang Yang
- Department of Radiology, Harvard Medical School, Harvard University, 200 Longwood Avenue, Boston, MA 02115, USA
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Balagurumoorthy P, Adelstein SJ, Kassis AI. Novel method for quantifying radiation-induced single-strand-break yields in plasmid DNA highlights 10-fold discrepancy. Anal Biochem 2011; 417:242-6. [PMID: 21741945 DOI: 10.1016/j.ab.2011.06.023] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2011] [Revised: 06/16/2011] [Accepted: 06/17/2011] [Indexed: 11/17/2022]
Abstract
The widely used agarose gel electrophoresis method for assessing radiation-induced single-strand-break (SSB) yield in plasmid DNA involves measurement of the fraction of relaxed-circular (C) form that migrates independently from the intact supercoiled (SC) form. We rationalized that this method may underestimate the SSB yield since the position of the relaxed-circular form is not altered when the number of SSB per DNA molecule is >1. To overcome this limitation, we have developed a novel method that directly probes and quantifies SSBs. Supercoiled (3)H-pUC19 plasmid samples were irradiated with γ-rays, alkali-denatured, dephosphorylated, and kinated with γ-[(32)P]ATP, and the DNA-incorporated (32)P activities were used to quantify the SSB yields per DNA molecule, employing a standard curve generated using DNA molecules containing a known number of SSBs. The same irradiated samples were analyzed by agarose gel and SSB yields were determined by conventional methods. Comparison of the data demonstrated that the mean SSB yield per plasmid DNA molecule of [21.2±0.59]×10(-2)Gy(-1) as measured by direct probing is ~10-fold higher than that obtained from conventional gel-based methods. These findings imply that the SSB yields inferred from agarose gels need reevaluation, especially when they were utilized in the determination of radiation risk.
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Yang Y, Adelstein SJ, Kassis AI. General approach to identifying potential targets for cancer imaging by integrated bioinformatics analysis of publicly available genomic profiles. Mol Imaging 2011; 10:123-134. [PMID: 21439257] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2023] Open
Abstract
Molecular imaging has moved to the forefront of drug development and biomedical research. The identification of appropriate imaging targets has become the touchstone for the accurate diagnosis and prognosis of human cancer. Particularly, cell surface- or membrane-bound proteins are attractive imaging targets for their aberrant expression, easily accessible location, and unique biochemical functions in tumor cells. Previously, we published a literature mining of potential targets for our in-house enzyme-mediated cancer imaging and therapy technology. Here we present a simple and integrated bioinformatics analysis approach that assembles a public cancer microarray database with a pathway knowledge base for ascertaining and prioritizing upregulated genes encoding cell surface- or membrane-bound proteins, which could serve imaging targets. As examples, we obtained lists of potential hits for six common and lethal human tumors in the prostate, breast, lung, colon, ovary, and pancreas. As control tests, a number of well-known cancer imaging targets were detected and confirmed by our study. Further, by consulting gene-disease and protein-disease databases, we suggest a number of significantly upregulated genes as promising imaging targets, including cell surface-associated mucin-1, prostate-specific membrane antigen, hepsin, urokinase plasminogen activator receptor, and folate receptors. By integrating pathway analysis, we are able to organize and map "focused" interaction networks derived from significantly dysregulated entity pairs to reflect important cellular functions in disease processes. We provide herein an example of identifying a tumor cell growth and proliferation subnetwork for prostate cancer. This systematic mining approach can be broadly applied to identify imaging or therapeutic targets for other human diseases.
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Affiliation(s)
- Yongliang Yang
- Department of Radiology, Harvard Medical School, Boston, MA 02115, USA
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Yang Y, Adelstein SJ, Kassis AI. General Approach to Identifying Potential Targets for Cancer Imaging by Integrated Bioinformatics Analysis of Publicly Available Genomic Profiles. Mol Imaging 2011. [DOI: 10.2310/7290.2010.00024] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Affiliation(s)
- Yongliang Yang
- From the Department of Radiology, Harvard Medical School, Boston, MA, and Center for Molecular Medicine, Department of Biological Engineering, Dalian University of Technology, Dalian, PR China
| | - S. James Adelstein
- From the Department of Radiology, Harvard Medical School, Boston, MA, and Center for Molecular Medicine, Department of Biological Engineering, Dalian University of Technology, Dalian, PR China
| | - Amin I. Kassis
- From the Department of Radiology, Harvard Medical School, Boston, MA, and Center for Molecular Medicine, Department of Biological Engineering, Dalian University of Technology, Dalian, PR China
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Abstract
The exponential growth of high-throughput Omics data has provided an unprecedented opportunity for new target identification to fuel the dried-up drug discovery pipeline. However, the bioinformatics analysis of large amount and heterogeneous Omics data has posed a great deal of technical challenges for experimentalists who lack statistical skills. Moreover, due to the complexity of human diseases, it is essential to analyze the Omics data in the context of molecular networks to detect meaningful biological targets and understand disease processes. Here, we describe an integrated bioinformatics analysis strategy and provide a running example to identify suitable targets for our in-house Enzyme-Mediated Cancer Imaging and Therapy (EMCIT) technology. In addition, we go through a few key concepts in the process, including corrected false discovery rate (FDR), Gene Ontology (GO), pathway analysis, and tissue specificity. We also describe popular programs and databases which allow the convenient annotation and network analysis of Omics data. We provide a practical guideline for researchers to quickly follow the protocol described and identify those targets that are pertinent to their work.
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Affiliation(s)
- Yongliang Yang
- Department of Radiology, Harvard Medical School, Harvard University, Boston, MA, USA
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Hricak H, Brenner DJ, Adelstein SJ, Frush DP, Hall EJ, Howell RW, McCollough CH, Mettler FA, Pearce MS, Suleiman OH, Thrall JH, Wagner LK. Managing radiation use in medical imaging: a multifaceted challenge. Radiology 2010; 258:889-905. [PMID: 21163918 DOI: 10.1148/radiol.10101157] [Citation(s) in RCA: 236] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
This special report aims to inform the medical community about the many challenges involved in managing radiation exposure in a way that maximizes the benefit-risk ratio. The report discusses the state of current knowledge and key questions in regard to sources of medical imaging radiation exposure, radiation risk estimation, dose reduction strategies, and regulatory options.
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Affiliation(s)
- Hedvig Hricak
- Department of Radiology, Memorial Sloan-Kettering Cancer Center, 1275 York Ave, Suite C-278, New York, NY, USA.
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Abstract
PURPOSE To delineate the mechanisms underlying induction of apoptosis in malignant cells irradiated by DNA-incorporated iodine-125 or gamma-photons. MATERIALS AND METHODS Human tumor cells (RKO, LS174T, TE671, and MCF7) were irradiated by DNA-incorporated 5-[125I]iodo-2'-deoxyuridine (125IdUrd) or by gamma-photons. Clonogenic survival was determined by the colony-forming assay. Caspase-3 induction was measured with a fluorogenic substrate assay, and DNA fragmentation was determined by ligation-mediated polymerase chain reaction. DNA arrays were used to assess the expression of the B-cell lymphoma/leukaemia-2 (Bcl-2) family and related genes in RKO cells and in caspase-3-gene-defective MCF7 cells. RESULTS After 125IdUrd or y-photon exposure, the highest induction of caspase-3 was observed in the radiation-sensitive cell lines (RKO and LS174T). DNA fragmentation was prominent in the radiosensitive cells and undetectable in TE671 (125IdUrd and gamma-photons) and MCF7 (125IdUrd only) cells. Exposure of RKO and MCF7 cells to 125I decay led to up-regulation of several pro-apoptotic and antiapoptotic Bcl-2 family genes whereas y-irradiation produced minimal activation. CONCLUSIONS Apoptosis generated by a DNA-incorporated Auger electron emitter is induced through the mitochondrial/caspase-3-mediated pathway and correlates with cellular radiosensitivity. Apoptosis caused by y-radiation can be signaled without activation of Bcl-2 family genes, and DNA fragmentation occurs with or without caspase-3 activation.
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Affiliation(s)
- Tetsuro Urashima
- Harvard Medical School, 200 Longwood Avenue, Armenise Building, D2-137, Boston, MA, USA
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Singh A, Yang Y, Adelstein SJ, Kassis AI. Synthesis and application of molecular probe for detection of hydroxyl radicals produced by Na(125)I and gamma-rays in aqueous solution. Int J Radiat Biol 2009; 84:1001-10. [PMID: 19061124 DOI: 10.1080/09553000802552143] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
PURPOSE To synthesize N-(3-(3-aminopropylamino)propyl)-2-oxo-2H-chromene-3-carboxamide (7), a novel DNA-binding, coumarin-based, fluorescent hydroxylradical ((*)OH) indicator and to assess its quantum efficiency compared with that of coumarin-3-carboxylic acid (1) and N1,N12-bis[2-oxo-2H-chromene-3-carbonyl]- 1,12-diamine-4,9-diazadodecane (9). MATERIALS AND METHODS Using computer-generated molecular modeling, 7 and 9 and their respective 7-hydroxylated derivatives 8 and 10 were docked onto DNA dodecamer d(CGCGAATTCGCG)2, the ligand-DNA complexes were energy minimized, and binding free energies and inhibition constants were calculated. Compound 7 was judged an appropriate target molecule and was synthesized. Compounds 1, 7, and 9 were incubated with Na(125)I or irradiated with (137)Cs gamma-rays, and the influence of pH, dose, type of radiation, and the concentration of indicator on fluorescence yield were determined. RESULTS Non-fluorescent 7 and 9 are converted to fluorescent, 7-hydroxylated derivatives 8 and 10 after interaction with (*)OH in aqueous solution. For 1, 7, and 9, hydroxylation yield increases linearly with both Na(125)I dose (0-700 x 10(6) decays) and (137)Cs dose (0-11.0 Gy). Fluorescence induction is significantly reduced at acidic pH and the fluorescent quantum yield of 8 is approximately 3 times that of 2 or 10 at pH 7.0. With Na(125)I incubation and gamma-ray irradiation, the fluorescence signal of 7 increases linearly with concentration and saturates at approximately 50 microM. CONCLUSION Compound 7 quantifies lower concentrations of (*)OH than do 1 and 9. This detector is therefore likely to be a good reporter of (*)OH produced within a few nanometers of DNA.
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Affiliation(s)
- Amarjit Singh
- Department of Radiology, Harvard Medical School, Boston, Massachusetts, USA
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Rebischung C, Hoffmann D, Stefani L, Desruet MD, Wang K, Adelstein SJ, Artignan X, Vincent F, Gauchez AS, Zhang H, Fagret D, Vuillez J, Kassis AI, Balosso J. First human treatment of resistant neoplastic meningitis by intrathecal administration of MTX plus (125)IUdR. Int J Radiat Biol 2009; 84:1123-9. [PMID: 19061137 DOI: 10.1080/09553000802395535] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
PURPOSE Neoplastic meningitis is often the final outcome of disseminated cancer and is rapidly lethal. Its limited treatment relies on systemic or intrathecal chemotherapy with methotrexate (MTX) or thiotepa. When 5-iodo-2'-deoxyuridine labeled with (125)I ((125)IUdR) is incorporated into the DNA of mitotic tumor cells, the Auger electrons emitted during iodine decay are highly cytotoxic. The radiotherapeutic efficacy of (125)IUdR administered intrathecally has also been established in animals bearing spinal cord tumors, and MTX is known to potentiate the response. This approach has not been tested in the clinic. METHODS A 44-year-old woman, with locally advanced pancreatic cancer, was treated for three years with complete systemic remission, but then relapsed with cytologically proven neoplastic meningitis. The patient was given four successive intrathecal injections of MTX (10 mg) every 12 h and, with the fourth dose, 1850 MBq (125)IUdR, followed by four additional MTX doses. The response was monitored by cytology and CA19.9 (carbohydrate antigen 19.9) levels in the cerebrospinal fluid (CSF) as well as by clinical status of the patient. RESULTS The follow-up of cytology and CA19.9 levels in the CSF showed dramatic improvement within 26 days followed by a biological relapse on Day +36. There was no evidence of local central nervous system toxicity. Three months later, neoplastic meningitis recurred and meningeal tumor infiltration was observed on magnetic resonance imaging. Six months after MTX-(125)IUdR treatment, the patient died. CONCLUSION (125)IUdR treatment proved to be feasible without acute neurological toxicity and seemed to have produced a biological response. This attempt provides the basis for designing prospective clinical trials.
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Affiliation(s)
- C Rebischung
- Department of Oncology, CHU de Grenoble, Grenoble cedex 9, France
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Abstract
Data mining of available biomedical data and information has greatly boosted target discovery in the 'omics' era. Target discovery is the key step in the biomarker and drug discovery pipeline to diagnose and fight human diseases. In biomedical science, the 'target' is a broad concept ranging from molecular entities (such as genes, proteins and miRNAs) to biological phenomena (such as molecular functions, pathways and phenotypes). Within the context of biomedical science, data mining refers to a bioinformatics approach that combines biological concepts with computer tools or statistical methods that are mainly used to discover, select and prioritize targets. In response to the huge demand of data mining for target discovery in the 'omics' era, this review explicates various data mining approaches and their applications to target discovery with emphasis on text and microarray data analysis. Two emerging data mining approaches, chemogenomic data mining and proteomic data mining, are briefly introduced. Also discussed are the limitations of various data mining approaches found in the level of database integration, the quality of data annotation, sample heterogeneity and the performance of analytical and mining tools. Tentative strategies of integrating different data sources for target discovery, such as integrated text mining with high-throughput data analysis and integrated mining with pathway databases, are introduced.
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Affiliation(s)
- Yongliang Yang
- Harvard Medical School, Harvard University, Department of Radiology, Armenise Building, Room D2-137, 200 Longwood Avenue, Boston, MA 02115, USA.
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Howell RW, Martin RF, Nikjoo H, Pomplun E, Terrissol M, Watanable R, Yasui L, Kassis AI, Adelstein SJ. Meeting overview. Int J Radiat Biol 2008; 84:957-8. [PMID: 19061119 DOI: 10.1080/09553000802545428] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Abstract
PURPOSE To determine double-strand-break (DSB) yields produced by decay of minor-groove-bound (123)I-labeled Hoechst 33342 ((123)IEH) in supercoiled (SC) and linear (L) forms of pUC19 DNA, to compare strand-break efficiency of (123)IEH with that of (125)IEH, and to examine the role of DNA topology in DSB induction by these Auger electron emitters. MATERIALS AND METHODS Tritium-labeled SC and L pUC19 DNA were incubated with (123)IEH (0-10.9 MBq) at 4 degrees C. After (123)I had completely decayed (10 days), samples were analyzed on agarose gel, and single-strand-break (SSB) and DSB yields were measured. RESULTS Each (123)I decay in SC DNA produces a DSB yield of 0.18 +/- 0.01. On the basis of DSB yields for (125)IEH (0.52 +/- 0.02 for SC and 1.62 +/- 0.07 for L, reported previously) and dosimetric expectations, a DSB yield of approximately 0.5 (3 x 0.18) per (123)I decay is expected for L DNA. However, no DSB are observed for the L form, even after approximately 2 x 10(11) decays of (123)I per microg DNA, whereas a similar number of (125)I decays produces DSB in approximately 40% of L DNA. CONCLUSION (123)IEH-induced DSB yield for SC but not L DNA is consistent with the dosimetric expectations for Auger electron emitters. These studies highlight the role of DNA topology in DSB production by Auger emitters and underscore the failure of current theoretical dosimetric methods per se to predict the magnitude of DSB.
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Balagurumoorthy P, Adelstein SJ, Kassis AI. Method to eliminate linear DNA from mixture containing nicked circular, supercoiled, and linear plasmid DNA. Anal Biochem 2008; 381:172-4. [PMID: 18638445 DOI: 10.1016/j.ab.2008.06.037] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2008] [Revised: 06/25/2008] [Accepted: 06/27/2008] [Indexed: 11/26/2022]
Abstract
Preparations of circular plasmid DNA in either supercoiled or nicked circular form often are contaminated with undesired linear DNA fragments arising from shearing/degradation of chromosomal DNA or linearization of plasmid DNA itself. We report a simple enzymatic method, using a combination of lambda exonuclease and RecJ(f), for the selective removal of linear DNA from such mixtures. lambda exonuclease digests one strand of linear duplex DNA in the 5' to 3' direction, whereas RecJ(f), a single-strand-specific exonuclease, digests the remaining complementary single strand into mononucleotides. This combination of exonucleases can remove linear DNA from a mixture of linear and supercoiled DNA, leaving the supercoiled form intact. Furthermore, the inability of lambda exonuclease to initiate digestion at nicks or gaps enables the removal of undesired linear DNA when nicked circular DNA has been enzymatically prepared from supercoiled DNA. This method can be useful in the preparation of homogeneous circular plasmid DNA required for therapeutic applications and biophysical studies.
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Balagurumoorthy P, Chen K, Adelstein SJ, Kassis AI. Auger electron-induced double-strand breaks depend on DNA topology. Radiat Res 2008; 170:70-82. [PMID: 18582152 PMCID: PMC2829305 DOI: 10.1667/rr1072.1] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2007] [Accepted: 02/09/2008] [Indexed: 11/03/2022]
Abstract
From a structural perspective, the factors controlling and the mechanisms underlying the toxic effects of ionizing radiation remain elusive. We have studied the consequences of superhelical/torsional stress on the magnitude and mechanism of DSBs induced by low-energy, short-range, high-LET Auger electrons emitted by (125)I, targeted to plasmid DNA by m-[(125)I]iodo-p-ethoxyHoechst 33342 ((125)IEH). DSB yields per (125)I decay for torsionally relaxed nicked (relaxed circular) and linear DNA (1.74+/-0.11 and 1.62+/-0.07, respectively) are approximately threefold higher than that for torsionally strained supercoiled DNA (0.52+/-0.02), despite the same affinity of all forms for (125)IEH. In the presence of DMSO, the DSB yield for the supercoiled form remains unchanged, whereas that for nicked and linear forms decreases to 1.05+/-0.07 and 0.76+/-0.03 per (125)I decay, respectively. DSBs in supercoiled DNA therefore result exclusively from direct mechanisms, and those in nicked and linear DNA, additionally, from hydroxyl radical-mediated indirect effects. Iodine-125 decays produce hydroxyl radicals along the tracks of Auger electrons in small isolated pockets around the decay site. We propose that relaxation of superhelical stress after radical attack could move a single-strand break lesion away from these pockets, thereby preventing further breaks in the complementary strand that could lead to DSBs.
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Affiliation(s)
| | - Kai Chen
- Department of Radiology, Harvard Medical School, Boston, Massachusetts 02115
| | - S. James Adelstein
- Department of Radiology, Harvard Medical School, Boston, Massachusetts 02115
| | - Amin I. Kassis
- Department of Radiology, Harvard Medical School, Boston, Massachusetts 02115
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Kassis AI, Korideck H, Wang K, Pospisil P, Adelstein SJ. Novel prodrugs for targeting diagnostic and therapeutic radionuclides to solid tumors. Molecules 2008; 13:391-404. [PMID: 18305426 PMCID: PMC6244955 DOI: 10.3390/molecules13020391] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2008] [Revised: 02/15/2008] [Accepted: 02/15/2008] [Indexed: 11/19/2022] Open
Abstract
Most cancer therapeutics (chemo, radiation, antibody-based, anti-angiogenic) are at best partially and/or temporarily effective. In general, the causes for failure can be summarized as: (i) poor diffusion and/or nonuniform distribution of drug/prodrug molecules in solid tumors; (ii) high drug concentration and retention in normal tissues (leading to side effects); (iii) requirement for plasma-membrane permeability and/or internalization of drug/prodrug molecules; (iv) low uptake of drug by tumor; (v) lack of retention of drug within tumor (most have gradient-driven reversible binding); and (vi) multidrug resistance. We are developing an innovative technology that aims to surmount these problems by actively concentrating and permanently entrapping radioimaging and radiotherapeutic prodrugs specifically within solid tumors. The approach will enable noninvasive sensing (imaging) and effective therapy of solid tumors, allowing tumor detection, diagnosis, and treatment to be closely coupled (personalized medicine).
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Affiliation(s)
- Amin I Kassis
- Department of Radiology, Harvard Medical School, Armenise Building, Room D2-137, 200 Longwood Avenue, Boston, Massachusetts 02115, USA.
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Abstract
A high-yield radioiodination method for various types of molecules is described. The approach employs DMSO as precursor solvent, a reaction ratio of 2-5 precursor molecules per iodine atom, 5-10 microg oxidant, and a 10-25 microl reaction volume. The solution is vortexed at room temperature for 1-5 min and progress of the reaction is assessed by HPLC. Radioiodinated products are obtained in > or = 95% yield and meet the requirements for radiotracer imaging, biodistribution studies, and molecular and cellular biology research.
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Affiliation(s)
- Ketai Wang
- Department of Radiology, Armenise Building Room D2-137, 200 Longwood Avenue, Harvard Medical School, Boston, MA 02115
| | - S. James Adelstein
- Department of Radiology, Armenise Building Room D2-137, 200 Longwood Avenue, Harvard Medical School, Boston, MA 02115
| | - Amin I. Kassis
- Department of Radiology, Armenise Building Room D2-137, 200 Longwood Avenue, Harvard Medical School, Boston, MA 02115
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Singh A, Chen K, Adelstein SJ, Kassis AI. Synthesis of Coumarin–Polyamine-Based Molecular Probe for the Detection of Hydroxyl Radicals Generated by Gamma Radiation. Radiat Res 2007; 168:233-42. [PMID: 17638412 DOI: 10.1667/rr0948.1] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2007] [Accepted: 03/15/2007] [Indexed: 11/03/2022]
Abstract
To develop a molecular probe for detection of hydroxyl radicals in the vicinity of DNA, the coumarin-polyamine complexes, N(1),N(12)-bis[2-oxo-2H-chromene-3-carbonyl]-1,12-diamine-4,9-diazadodecane (5) and tris[2-(2-oxo-2H-chromene-3-carboxamido)ethyl]amine (7), and their hydroxylated derivatives, N(1),N(12)-bis[7-hydroxy-2-oxo-2H-chromene-3-carbonyl]-1,12-diamine-4,9-diazadodecane (6) and tris[2-(7-hydroxy-2-oxo-2H-chromene-3-carboxamido)ethyl]amine (8), have been synthesized. Using computer-generated molecular modeling, the derivatives have been docked onto DNA dodecamer d(CGCGAATTCGCG)(2), the ligand-DNA complexes have been minimized, and the free binding energies (DeltaG(binding)) and inhibition constants (K(i)) have been calculated. Compound 7 is not water-soluble at the concentrations required for the project. When aqueous solutions of 5 are irradiated with gamma rays, the relationship between induced fluorescence and dose is linear in the range of 0 to 10 Gy. The fluorescence emission spectrum of irradiated 5 is similar to that of its dihydroxy derivative 6, indicating conversion of 5 to 6, and induction of fluorescence records formation of hydroxyl radicals in aqueous solution. The dicoumarin-polyamine 5, a novel compound for the detection of hydroxyl radicals close to DNA, is a sensitive and quantitative probe with potential for applications in biological systems.
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Affiliation(s)
- Amarjit Singh
- Department of Radiology, Harvard Medical School, Boston, MA 02115, USA
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Wang K, Kirichian AM, Aowad AFA, Adelstein SJ, Kassis AI. Evaluation of Chemical, Physical, and Biologic Properties of Tumor-Targeting Radioiodinated Quinazolinone Derivative. Bioconjug Chem 2007; 18:754-64. [PMID: 17385903 DOI: 10.1021/bc0602937] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Our group is developing a novel technology, enzyme-mediated cancer imaging and therapy (EMCIT), that aims to entrap radioiodinated compounds within solid tumors for noninvasive tumor detection and therapy. In this approach, a water-soluble, radioiodinated prodrug is hydrolyzed in vivo to a highly water-insoluble compound by an enzyme overexpressed extracellularly by tumor cells. We have synthesized and characterized the water-soluble prodrug, 2-(2'-phosphoryloxyphenyl)-6-[(125)I]iodo-4-(3H)-quinazolinone [(125)I]5, which is readily hydrolyzed by alkaline phosphatase, an enzyme expressed by many tumor cell lines, to a water-insoluble drug, 2-(2'-hydroxyphenyl)-6-[(125)I]iodo-4-(3H)-quinazolinone [(125)I]1. In the course of our study, we discovered that ammonium 2-(2'-phosphoryloxyphenyl)-6-tributylstannyl-4-(3H)-quinazolinone, an intermediate in the radioiodination of the prodrug, exists as two isomers (3 and 4) whose radioiodination leads, respectively, to [(125)I]6 and [(125)I]5. These prodrugs have different in vitro and in vivo biologic activities. Compound 6 is not hydrolyzed by alkaline phosphatase (ALP), whereas 5 is highly soluble (mg/mL) in aqueous solution and is rapidly dephosphorylated in the presence of ALP to 1, a water-insoluble molecule (ng/mL). Mouse biodistribution studies indicate that [(125)I]6 has high uptake in kidney and liver and [(125)I]5 has very low uptake in all normal organs. Compounds 3 and 6 are converted, respectively, to 4 and 5 after incubation in DMSO. The stability of 5 in human serum is high. The minimum ALP concentration needed to hydrolyze 5 is much greater than the ALP level in the blood of patients with cancer, and the latter should not affect the pharmacokinetics of the compound. Incubation of 5 with viable human and mouse tumor-cell lines--but not with normal human cells and mouse tissues--leads to its hydrolysis and the formation of large crystals of 1. We expect that 5 will also be hydrolyzed in vivo by tumor cells that express phosphatase activity extracellularly and anticipate the specific precipitation of radioiodinated 1 within tumor cell clusters. This should lead to high tumor-to-normal-tissue ratios and enable imaging (SPECT/PET) and radionuclide therapy of solid tumors.
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Affiliation(s)
- Ketai Wang
- Harvard Medical School, Department of Radiology, 200 Longwood Avenue, Boston, Massachusetts 02115, USA
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Urashima T, Nagasawa H, Wang K, Adelstein SJ, Little JB, Kassis AI. Induction of apoptosis in human tumor cells after exposure to Auger electrons: comparison with gamma-ray exposure. Nucl Med Biol 2007; 33:1055-63. [PMID: 17127180 PMCID: PMC1751571 DOI: 10.1016/j.nucmedbio.2006.09.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2006] [Revised: 09/18/2006] [Accepted: 09/19/2006] [Indexed: 12/21/2022]
Abstract
To clarify the contribution of apoptosis to cell death in four human solid tumor cell lines, clonogenic cell survival (indicator of radiosensitivity) and induction of caspase-3 (CASP-3)/caspase-3-like proteases (CASP-3LP) and the production of DNA fragmentation (markers for apoptosis) were studied in RKO, LS174T, MCF7 and TE671 cells exposed to DNA-incorporated Auger-electron-emitting (125)I (5-[(125)I]iodo-2'-deoxyuridine) or gamma-radiation. Clonogenic survival was assessed by colony-forming assay, CASP-3/CASP-3LP induction with a fluorogenic substrate and DNA fragmentation by ligation-mediated polymerase chain reaction. For (125)I, log dose-survival curves had no shoulder [high-linear-energy-transfer (LET)-like] and decreased exponentially at different rates in various cell lines. Induction of CASP-3/CASP-3LP in radiosensitive RKO and LS174T cells was threefold greater than that in radioresistant TE671 and MCF7 cells. Nucleosomal laddering in (125)I-radiosensitive cell lines was dose-dependent, and no laddering was detected in radioresistant lines. For gamma-radiation, the survival curve for LS174T cells was monoexponential and that for the other lines exhibited a distinct shoulder (low-LET-like). The most radiosensitive cell line, LS174T, showed the highest induction of CASP-3/CASP-3LP, and the most radioresistant line, TE671, showed the lowest induction. Although DNA laddering was not detectable in TE671 cells, it was observed in other lines, being most prominent in LS174T cells. We conclude that apoptosis initiated by DNA-incorporated (125)I is dose-dependent, correlates with cell radiosensitivity and takes place through a CASP-3-mediated pathway, whereas that after gamma-irradiation probably occurs via a CASP-3-independent pathway and/or a CASP-3-mediated pathway and does not correlate with cell radiosensitivity.
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Affiliation(s)
- Tetsuro Urashima
- Department of Radiology, Harvard Medical School, Boston, MA 02115, USA
| | - Hatsumi Nagasawa
- Department of Radiological Science, Colorado State University, Fort Collins, CO 80523, USA; and
| | - Ketai Wang
- Department of Radiology, Harvard Medical School, Boston, MA 02115, USA
| | | | - John B. Little
- Department of Radiation Biology, Harvard School of Public Health, Boston, MA 02115, USA
| | - Amin I. Kassis
- Department of Radiology, Harvard Medical School, Boston, MA 02115, USA
- *Address correspondence to Amin I. Kassis, Ph.D., Harvard Medical School, 200 Longwood Avenue, Armenise Building, Boston, MA 02115, USA; telephone: 617-432-7777, fax 617-432-2419, e-mail
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Pospisil P, Wang K, Al Aowad AF, Iyer LK, Adelstein SJ, Kassis AI. Computational Modeling and Experimental Evaluation of a Novel Prodrug for Targeting the Extracellular Space of Prostate Tumors. Cancer Res 2007; 67:2197-205. [PMID: 17332350 DOI: 10.1158/0008-5472.can-06-3309] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
We are developing a noninvasive approach for targeting imaging and therapeutic radionuclides to prostate cancer. Our method, Enzyme-Mediated Cancer Imaging and Therapy (EMCIT), aims to use enzyme-dependent, site-specific, in vivo precipitation of a radioactive molecule within the extracellular space of solid tumors. Advanced methods for data mining of the literature, protein databases, and knowledge bases (IT. Omics LSGraph and Ingenuity Systems) identified prostatic acid phosphatase (PAP) as an enzyme overexpressed in prostate cancer and secreted in the extracellular space. Using AutoDock 3.0 software, the prodrug ammonium 2-(2'-phosphoryloxyphenyl)-6-iodo-4-(3H)-quinazolinone (IQ(2-P)) was docked in silico into the X-ray structure of PAP. The data indicate that IQ(2-P) docked into the PAP active site with a calculated inhibition constant (K(i)) more favorable than that of the PAP inhibitor alpha-benzylaminobenzylphosphonic acid. When (125)IQ(2-P), the radioiodinated form of the water-soluble prodrug, was incubated with PAP, rapid hydrolysis of the compound was observed as exemplified by formation of the water-insoluble 2-(2'-hydroxyphenyl)-6-[(125)I]iodo-4-(3H)-quinazolinone ((125)IQ(2-OH)). Similarly, the incubation of IQ(2-P) with human LNCaP, PC-3, and 22Rv1 prostate tumor cells resulted in the formation of large fluorescent IQ(2-OH) crystals. No hydrolysis was seen in the presence of normal human cells. Autoradiography of tumor cells incubated with (125)IQ(2-P) showed accumulation of radioactive grains ((125)IQ(2-OH)) around the cells. We anticipate that the EMCIT approach will enable the active in vivo entrapment of radioimaging and radiotherapeutic compounds within the extracellular spaces of primary prostate tumors and their metastases.
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Affiliation(s)
- Pavel Pospisil
- Department of Radiology, Harvard Medical School, 200 Longwood Avenue, Boston, MA 02115, USA
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Chen K, Aowad AFA, Adelstein SJ, Kassis AI. Molecular-Docking-Guided Design, Synthesis, and Biologic Evaluation of Radioiodinated Quinazolinone Prodrugs. J Med Chem 2007; 50:663-73. [PMID: 17256924 DOI: 10.1021/jm060944k] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Enzyme-mediated cancer imaging and therapy (EMCIT) is a novel approach in which radioactive water-soluble molecules are precipitated in vivo following their hydrolysis by extracellular enzymes overexpressed by cancer cells. AutoDock 3.0 was used to model the interaction-binding between a series of iodinated quinazolinone derivatives and human placental alkaline phosphatase (PLAP, crystal structure in the Protein Data Bank) and to assess the effects of structural modification of the derivatives. Ammonium 2-(2',4'-diphosphoryloxyphenyl)-6-iodo-4-(3H)-quinazolinone (IQ2-P,4-P), having the most favorable calculated inhibition constant, was synthesized and characterized. Concentration-dependent, PLAP-mediated conversion of IQ2-P,4-P (4)/125IQ2-P,4-P (6) to water-insoluble 2-(2',4'-dihydroxyphenyl)-6-[127I/125I]iodo-4-(3H)-quinazolinone (127IQ2-OH,4-OH (2)/125IQ2-OH,4-OH (7)) was observed in solution. Autoradiography indicated that 6 is hydrolyzed by human cancer cells and the resulting 7 precipitates on exterior cell surfaces. Biodistribution studies in mice demonstrated that 6 is minimally retained by normal tissues. The findings support the validity of the EMCIT approach.
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Affiliation(s)
- Kai Chen
- Department of Radiology, Harvard Medical School, Boston, Massachusetts 02115, USA
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Chen K, Wang K, Kirichian AM, Al Aowad AF, Iyer LK, Adelstein SJ, Kassis AI. In silico design, synthesis, and biological evaluation of radioiodinated quinazolinone derivatives for alkaline phosphatase–mediated cancer diagnosis and therapy. Mol Cancer Ther 2006; 5:3001-13. [PMID: 17172404 DOI: 10.1158/1535-7163.mct-06-0465] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
As part of the development of enzyme-mediated cancer imaging and therapy, a novel technology to entrap water-insoluble radioactive molecules within solid tumors, we show that a water-soluble, radioactive quinazolinone prodrug, ammonium 2-(2'-phosphoryloxyphenyl)-6-[125I]iodo-4-(3H)-quinazolinone (125IQ(2-P)), is hydrolyzed by alkaline phosphatase to a water-insoluble, radiolabeled drug, 2-(2'-hydroxyphenyl)-6-[125I]iodo-4-(3H)-quinazolinone (125IQ(2-OH)). Biodistribution data suggest the existence of two isoforms of the prodrug (IQ(2-P(I)) and IQ(2-P)), and this has been confirmed by their synthesis and characterization. Structural differences of the two isoforms have been examined using in silico molecular modeling techniques and docking methods to describe the interaction/binding between the isoforms and human placental alkaline phosphatase (PLAP), a tumor cell, membrane-associated, hydrolytic enzyme whose structure is known by X-ray crystallographic determination. Docking data show that IQ(2-P), but not IQ(2-P(I)), fits the active binding site of PLAP favorably and interacts with the catalytic amino acid Ser(92), which plays an important role in the hydrolytic process. The binding free energies (DeltaG(binding)) of the isoforms to PLAP predict that IQ(2-P) will be the better substrate for PLAP. The in vitro incubation of the isoforms with PLAP leads to the rapid hydrolysis of IQ(2-P) only and confirms the in silico expectations. Fluorescence microscopy shows that in vitro incubation of IQ(2-P) with mouse and human tumor cells causes the extracellular, alkaline phosphatase-mediated hydrolysis of the molecule and precipitation of fluorescent crystals of IQ(2-OH). No hydrolysis is seen in the presence of normal mouse and human cells. Furthermore, the intratumoral injection of 125IQ(2-P) into alkaline phosphatase-expressing solid human tumors grown s.c. in nude rats results in efficient hydrolysis of the compound and retention of approximately 70% of the injected radioactivity, whereas similar injection into normal tissues (e.g., muscle) does not produce any measurable hydrolysis (approximately 1%) or retention of radioactivity at the injected site. These studies support the enzyme-mediated cancer imaging and therapy technology and show the potential of such quinazolinone derivatives in the in vivo radiodetection (123I/124I) and therapy (131I) of solid tumors.
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Affiliation(s)
- Kai Chen
- Department of Radiology, Harvard Medical School, Armenise Building, Room 137, 200 Longwood Avenue, Boston, MA 02115, USA
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Balagurumoorthy P, Chen K, Bash RC, Adelstein SJ, Kassis AI. Mechanisms Underlying Production of Double-Strand Breaks in Plasmid DNA after Decay of125I-Hoechst. Radiat Res 2006; 166:333-44. [PMID: 16881734 DOI: 10.1667/rr3591.1] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Previously, the kinetics of strand break production by (125)I-labeled m-iodo-p-ethoxyHoechst 33342 ((125)IEH) in supercoiled (SC) plasmid DNA had demonstrated that approximately 1 DSB is produced per (125)I decay both in the presence and absence of the hydroxyl radical scavenger DMSO. In these experiments, an (125)IEH:DNA molar ratio of 42:1 was used. We now hypothesize that this DSB yield (but not the SSB yield) may be an overestimate due to subsequent decays occurring in any of the 41 (125)IEH molecules still bound to nicked (N) DNA. To test our hypothesis, (125)IEH was incubated with SC pUC19 plasmids ((125)IEH:DNA ratio of approximately 3:1) and the SSB and DSB yields were quantified after the decay of (125)I. As predicted, the number of DSBs produced per (125)I decay is one-half that reported previously ( approximately 0.5 compared to approximately 1, +/- DMSO) whereas the number of SSBs ( approximately 3/(125)I decay) is similar to that obtained previously ( approximately 90% are generated by OH radicals). Direct visualization by atomic force microscopy confirms formation of L and N DNA after (125)IEH decays in SC DNA and supports the strand break yields reported. These findings indicate that although SSB production is independent of the number of (125)IEH bound to DNA, the DSB yield can be augmented erroneously by (125)I decays occurring in N DNA. Further analysis indicates that 17% of SSBs and 100% of DSBs take place within the plasmid molecule in which an (125)IEH molecule decays, whereas 83% of SSBs are formed in neighboring plasmid DNA molecules.
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Kishikawa H, Wang K, Adelstein SJ, Kassis AI. Inhibitory and stimulatory bystander effects are differentially induced by Iodine-125 and Iodine-123. Radiat Res 2006; 165:688-94. [PMID: 16802869 DOI: 10.1667/rr3567.1] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The bystander effect, originating from cells irradiated in vitro, describes responses of surrounding cells not targeted by the radiation. Previously we demonstrated that the subcutaneous injection into nude mice of human adenocarcinoma LS174T cells lethally irradiated by Auger electrons from the decay of DNA-incorporated (125)I inhibits growth of co-injected LS174T cells (inhibitory bystander effect; Proc. Natl. Acad. Sci. USA 99, 13765-13770, 2002). We have repeated these studies using cells exposed to lethal doses of (123)I, an Auger electron emitter whose emission spectrum is identical to that of (125)I, and report herein that the decay of (123)I within tumor cell DNA stimulates the proliferation of neighboring unlabeled tumor cells growing subcutaneously in nude mice (stimulatory bystander effect). Similar inhibitory bystander effects ((125)I) and stimulatory bystander effects ((123)I) are obtained in vitro. Moreover, supernatants from cultures with (125)I-labeled cells are positive for tissue inhibitors of metalloproteinases (TIMP1 and TIMP2), and those from cultures with (123)I-labeled cells are positive for angiogenin. These findings call for the re-evaluation of current dosimetric approaches for the estimation of dose-response relationships in individuals after radiopharmaceutical administration or radiocontamination and demonstrate a need to adjust all "calculated" dose estimates by a dose modification factor (DMF), a radionuclide-specific constant that factors in hitherto not-so-well recognized biophysical processes.
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Affiliation(s)
- Hiroko Kishikawa
- Department of Radiology, Harvard Medical School, Boston, Massachusetts 02115, USA
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Kortylewicz ZP, Baranowska-Kortylewicz J, Adelstein SJ, Carmel AD, Kassis AI. Radiolabeled biotin amides from triazenyl precursors: Synthesis, binding, and in-vivo properties. J Labelled Comp Radiopharm 2006. [DOI: 10.1002/jlcr.2580341203] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Pospisil P, Iyer LK, Adelstein SJ, Kassis AI. A combined approach to data mining of textual and structured data to identify cancer-related targets. BMC Bioinformatics 2006; 7:354. [PMID: 16857057 PMCID: PMC1555615 DOI: 10.1186/1471-2105-7-354] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2006] [Accepted: 07/20/2006] [Indexed: 11/24/2022] Open
Abstract
Background We present an effective, rapid, systematic data mining approach for identifying genes or proteins related to a particular interest. A selected combination of programs exploring PubMed abstracts, universal gene/protein databases (UniProt, InterPro, NCBI Entrez), and state-of-the-art pathway knowledge bases (LSGraph and Ingenuity Pathway Analysis) was assembled to distinguish enzymes with hydrolytic activities that are expressed in the extracellular space of cancer cells. Proteins were identified with respect to six types of cancer occurring in the prostate, breast, lung, colon, ovary, and pancreas. Results The data mining method identified previously undetected targets. Our combined strategy applied to each cancer type identified a minimum of 375 proteins expressed within the extracellular space and/or attached to the plasma membrane. The method led to the recognition of human cancer-related hydrolases (on average, ~35 per cancer type), among which were prostatic acid phosphatase, prostate-specific antigen, and sulfatase 1. Conclusion The combined data mining of several databases overcame many of the limitations of querying a single database and enabled the facile identification of gene products. In the case of cancer-related targets, it produced a list of putative extracellular, hydrolytic enzymes that merit additional study as candidates for cancer radioimaging and radiotherapy. The proposed data mining strategy is of a general nature and can be applied to other biological databases for understanding biological functions and diseases.
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Affiliation(s)
- Pavel Pospisil
- Harvard Medical School, Department of Radiology, 200 Longwood Avenue, Boston, Massachusetts, USA
| | - Lakshmanan K Iyer
- Bauer Center for Genomics Research, Harvard University, 7 Divinity Avenue, Cambridge, Massachusetts, USA
| | - S James Adelstein
- Harvard Medical School, Department of Radiology, 200 Longwood Avenue, Boston, Massachusetts, USA
| | - Amin I Kassis
- Harvard Medical School, Department of Radiology, 200 Longwood Avenue, Boston, Massachusetts, USA
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Wang K, Adelstein SJ, Kassis AI. Radiotracer-based method for determining water solubility of highly insoluble compounds. J Labelled Comp Radiopharm 2006. [DOI: 10.1002/jlcr.1081] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Semnani ES, Wang K, Adelstein SJ, Kassis AI. 5-[123I/125I]iodo-2'-deoxyuridine in metastatic lung cancer: radiopharmaceutical formulation affects targeting. J Nucl Med 2005; 46:800-6. [PMID: 15872354] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/02/2023] Open
Abstract
UNLABELLED This study assesses targeting of lung metastases in mice with the radioiodinated thymidine analog 5-[(123)I/(125)I]iodo-2'-deoxyuridine ((123)I-IUdR/(125)I-IUdR), formulated with varying amounts of tributyltin precursor and injected intravenously. METHODS Six- to 8-wk-old C57BL/6 mice were injected intravenously with B16F10 melanoma cells. Two weeks later, when lung tumors were established, the animals were injected intravenously with (125)I-IUdR synthesized using 1, 35, 100, 150, 200, or 250 microg 5-tributylstannyl-2'-deoxyuridine (SnUdR) in the presence of an oxidant. Nontumor-bearing mice were also injected with these formulations and served as control animals. Twenty-four hours later, the animals were killed, and the radioactivity associated with the lungs and other tissues was measured in a gamma-counter. The percentage injected dose per gram tissue (%ID/g) and tumor-to-nontumor ratios (T/NT ratios) were calculated. Phosphor imaging was done on lungs from tumor-bearing and nontumor-bearing mice injected with (125)I-IUdR formulated with each tin precursor concentration. Scintigraphy was also performed 3 and 24 h after intravenous injection of (123)I-IUdR. RESULTS The %ID/g (125)I-IUdR was higher in lungs of tumor-bearing animals than in lungs of control animals. Although the increase in SnUdR present led to a small but statistically significant decrease in the radioactive content of normal lungs, a 3-fold increase was observed in the lungs of tumor-bearing animals with radiopharmaceutical formulated with 100 microg SnUdR (5 microg per mouse). This enhancement in radioactive uptake by the lungs led to approximately 14-fold increases in T/NT ratios. Phosphor imaging ((125)I-IUdR) of lungs as well as scintigraphy ((123)I-IUdR) of whole animals substantiated these findings. CONCLUSION The formulation for the synthesis of radio-IUdR that leads to the highest %ID/g in tumor and the best T/NT ratio has been identified. Further studies are required to determine the factors responsible for specific enhancement in IUdR tumor uptake.
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Abstract
PURPOSE By using computer-assisted molecular modeling software, to assess the effects of structural modification on the interaction of 125I-labeled iodoHoechst ligands and DNA and to design new analogs with specified distances between the Auger-electron-emitting 125I atom and the DNA central axis. MATERIALS AND METHODS The Lamarckian genetic algorithm (AutoDock 3.0) was used to model the interaction between DNA and m-iodo-p-methoxyHoechst (IMH), a ligand whose binding to the minor groove of DNA has been demonstrated (crystal structure) and which is available in the Protein Data Bank. m-Iodo-p-ethoxyHoechst (IEH), a radioligand we had previously synthesized and characterized, was then docked onto DNA, the IEH-DNA complex minimized, and the binding free energy and inhibition constant (Ki) estimated and compared with those for IMH-DNA. Using the protocol, several novel iodoHoechst analogs (IH-A and IH-B) were designed. Finally, Insight II was used to measure the distances between the iodine atom (e.g. 125I) of these Hoechst analogs and of 5-iodo-2'-deoxyuridine (IdUrd) and the central axis of the targeted DNA, and these values were correlated with the expected/measured DSB yield following 125I decay. RESULTS The docking of IMH and DNA leads to a ligand-DNA complex approximately 1 A RMSD (root mean square deviation) from the crystal-structure position, and the IEH-DNA complex also has a small RMSD (1.27 A). The distances between the 125I atom and the DNA central axis are estimated as 8.61 A for IMH, 9.20 A for IEH and 5.7A for IdUrd. For the newly designed analogs, the distances from the 125I atom to the central DNA axis are 10.92 A for IH-A and 16.39 A for IH-B. CONCLUSION These software programs can predict the reactivity of newly designed radiolabelled molecules with their targeted DNA molecules by molecular modeling prior to their chemical synthesis.
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Affiliation(s)
- Kai Chen
- Harvard Medical School, 200 Longwood Avenue, Armenise Building, D2-137, Boston, MA 02115-5729, USA
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Kassis AI, Kirichian AM, Wang K, Semnani ES, Adelstein SJ. Therapeutic potential of 5-[125I]iodo-2'-deoxyuridine and methotrexate in the treatment of advanced neoplastic meningitis. Int J Radiat Biol 2005; 80:941-6. [PMID: 15764406 DOI: 10.1080/09553000400017671] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
PURPOSE To assess the therapeutic potential of methotrexate (MTX) and 5-[1251]liodo-2'-deoxyuridine (125IdUrd) administered sequentially in rats bearing advanced (ten-day-old) intrathecal (i.t.) TE671 human rhabdomyosarcoma tumours. MATERIALS AND METHODS Nude rats were injected with TE671 cells through an i.t. placed catheter. Ten days later, the animals were injected i.t. over a 12-day period with (i) saline daily, (ii) MTX every other day, (iii) 125IdUrd every other day, or (iv) MTX and 125IdUrd on alternating days. Onset of paralysis was determined as a function of time, and the medians for onset (M), percentage of cells killed (% kill), and log cell kill were calculated. RESULTS The data show that (i) injection of MTX leads to a moderate delay in the onset of paralysis (M(MTX) = 29 d versus Msaline = 20 d), (ii) administration of 125IdUrd is more effective (M(IdUrd) = 36 d), and (iii) sequential administration of MTX- 125IdUrd further increases the therapeutic efficacy of 125IdUrd (M(MTX)-IdUrd = 47 d). CONCLUSIONS Intrathecal injection of MTX-(125)IdUrd is efficacious in the therapy of advanced intrathecal tumours.
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Affiliation(s)
- Amin I Kassis
- Harvard Medical School, Armenise Building, D2-137, 200 Longwood Avenue, Boston, MA 02115-5729, USA.
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Kassis AI, Adelstein SJ. Radiobiologic principles in radionuclide therapy. J Nucl Med 2005; 46 Suppl 1:4S-12S. [PMID: 15653646] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/01/2023] Open
Abstract
Although the general radiobiologic principles underlying external beam therapy and radionuclide therapy are the same, there are significant differences in the radiobiologic effects observed in mammalian cells. External beam and brachytherapy emissions are composed of photons, whereas radiations of interest in radionuclide therapy are particulate. The special features that characterize the biologic effects consequent to the traversal of charged particles through mammalian cells are explored with respect to DNA lesions and cellular responses. Information about the ways in which these radionuclides are used to treat cancers in experimental models are highlighted.
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Affiliation(s)
- Amin I Kassis
- Department of Radiology, Harvard Medical School, Boston, MA 02115, USA.
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Chen K, Adelstein SJ, Kassis AI. Molecular modeling of the interaction of iodinated Hoechst analogs with DNA: implications for new radiopharmaceutical design. ACTA ACUST UNITED AC 2004. [DOI: 10.1016/j.theochem.2004.08.032] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Britz-Cunningham SH, Adelstein SJ. Molecular targeting with radionuclides: state of the science. J Nucl Med 2003; 44:1945-61. [PMID: 14660721] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/27/2023] Open
Abstract
Inherent in the application of advances in biomedical science to nuclear medicine is the concept of molecular targeting: the in vivo concentration of labeled tracer by a gene, its transcribed DNA, or its protein product. This mechanism of localization has been and is being exploited for both nuclear imaging and radioisotopic therapy. Agents, such as antisense molecules, aptamers, antibodies, and antibody fragments, can be aimed at molecular targets. Tumor and nerve cell receptors provide such targets. So do certain cellular physiologic activities, including metabolism, hypoxia, proliferation, apoptosis, angiogenesis, response to infection, and multiple drug resistance. In this article we review the principles of molecular targeting based on radioisotopic methods and provide examples from the literature. We discuss applications to imaging and therapy and point out the hurdles that must be overcome in bringing molecular targeting to clinical reality.
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Affiliation(s)
- Scott H Britz-Cunningham
- Joint Program in Nuclear Medicine, Harvard Medical School, and Department of Radiology, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA.
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Bodei L, Kassis AI, Adelstein SJ, Mariani G. Radionuclide Therapy with Iodine-125 and Other Auger–Electron-Emitting Radionuclides: Experimental Models and Clinical Applications. Cancer Biother Radiopharm 2003; 18:861-77. [PMID: 14969599 DOI: 10.1089/108497803322702833] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Auger-electron emitters represent an attractive alternative to beta-particle emitters for cancer therapy if they can be placed intracellularly, especially in close proximity to (or within) nuclear DNA. Based on investigations in animal tumor models, including those for ovarian cancer, bladder cancer, and brain and spinal cord tumors, in which the thymidine analog 5-radioiodo-2'-deoxyuridine (*IUdR) has been shown to be therapeutically efficacious, it is hypothesized that iodine-125 and other Auger-electron-emitting radionuclides might be valuable in the treatment of certain malignant diseases, assuming that uptake of the radiopharmaceutical by tumor cells exceeds that by normal dividing cells. Preliminary patient studies have shown that this requirement can be met partially by the locoregional administration of the radiopharmaceutical and metabolic modulation of its uptake by tumor cells. Investigators continue to seek molecules that can carry Auger-electron emitters to nuclear DNA, especially those radionuclides with higher Auger-electron yields and varying half-lives.
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Affiliation(s)
- Lisa Bodei
- Nuclear Medicine Division, European Institute of Oncology, Milan, Italy
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Adelstein SJ, Kassis AI, Bodei L, Mariani G. Radiotoxicity of iodine-125 and other auger-electron-emitting radionuclides: background to therapy. Cancer Biother Radiopharm 2003; 18:301-16. [PMID: 12954118 DOI: 10.1089/108497803322285062] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Auger-electron cascades with their ability to deposit energy in extremely small volumes, typically in the range of cubic nanometers, have served as valuable probes of radiobiologic phenomena. Results from their experimental use form part of the evidence that nuclear DNA is the most radiosensitive cell element; that chromosomal aberrations and large scale double-strand breaks are correlated with reproductive survival; that neoplastic transformation and also mutagenesis are greatest at low doses with high specific ionization; and that, like high linear-energy-transfer radiation, Auger-electron cascades can lead to bystander effects. We have also learned that radiobiologic responses to Auger-electron emission are particularly sensitive to the site of decay, not only within the cell but also in the nucleus within the fine structure of chromatin.
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Affiliation(s)
- S James Adelstein
- Experimental Nuclear Medicine, Department of Radiology, Harvard Medical School, Boston, Massachusetts, USA
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Adelstein SJ. Biologic responses to low doses of ionizing radiation: adaptive response versus bystander effect. J Nucl Med 2003; 44:125; author reply 125-6. [PMID: 12515886] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/28/2023] Open
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Abstract
The bystander effect, originating from cells irradiated in vitro, describes the biologic response(s) of surrounding cells not directly targeted by a radiation insult. To overcome the limitations of in vitro tissue culture models and determine whether a bystander effect that is initiated by the in vivo decay of a radionuclide can be demonstrated in an animal, the ability of 5-[(125)I]iodo-2'-deoxyuridine ((125)IUdR)-labeled tumor cells to exert a damaging effect on neighboring unlabeled tumor cells growing s.c. in nude mice has been investigated. When mice are injected with a mixture of human colon LS174T adenocarcinoma cells and LS174T cells prelabeled with lethal doses of DNA-incorporated (125)I, a distinct inhibitory effect on the growth of s.c. tumor (derived from unlabeled cells) is observed. Because (i) the (125)I present within the cells is DNA-bound, (ii) approximately 99% of the electrons emitted by the decaying (125)I atoms have a subcellular range (<0.5 microm), and (iii) the overall radiation dose deposited by radiolabeled cells in the unlabeled cells within the growing tumor is <10 cGy, we conclude that the results obtained are a consequence of a bystander effect that is generated in vivo by factor(s) present within and/or released from the (125)IUdR-labeled cells. These in vivo findings significantly impact the current dogma for assessing the therapeutic potential of internally administered radionuclides. They also call for reevaluation of the approaches currently used for estimating the risks to individuals and populations inadvertently exposed internally to radioactivity as well as to patients undergoing routine diagnostic nuclear medical procedures.
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MESH Headings
- Animals
- Cell Division/radiation effects
- DNA, Neoplasm/metabolism
- DNA, Neoplasm/radiation effects
- Gamma Rays/therapeutic use
- Humans
- Idoxuridine/metabolism
- Idoxuridine/therapeutic use
- In Vitro Techniques
- Iodine Radioisotopes/metabolism
- Iodine Radioisotopes/therapeutic use
- Male
- Mice
- Mice, Nude
- Models, Immunological
- Neoplasm Transplantation
- Neoplasms, Experimental/immunology
- Neoplasms, Experimental/metabolism
- Neoplasms, Experimental/pathology
- Neoplasms, Experimental/radiotherapy
- Radiobiology
- Radiopharmaceuticals/metabolism
- Radiopharmaceuticals/therapeutic use
- Radiotherapy Dosage
- Transplantation, Heterologous
- Tumor Cells, Cultured
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Affiliation(s)
- Lanny Y Xue
- Departments of Radiology and Radiation Oncology, Harvard Medical School, Boston, MA 02115, USA
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Ho NH, Harapanhalli RS, Dahman BA, Chen K, Wang K, Adelstein SJ, Kassis AI. Synthesis and biologic evaluation of a radioiodinated quinazolinone derivative for enzyme-mediated insolubilization therapy. Bioconjug Chem 2002; 13:357-64. [PMID: 11906274 DOI: 10.1021/bc010093p] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We have developed a new strategy that aims to concentrate therapeutic radionuclides within solid tumors. This approach, which we have named EMIT (enzyme-mediated insolubilization therapy), is a method for enzyme-dependent, site-specific, in vivo precipitation of a radioactive molecule (from a water-soluble precursor) within the extracellular space of solid tumors. The prodrug, ammonium 2-(2'-phosphoryloxyphenyl)-6-iodo-4-(3H)-quinazolinone, labeled with iodine-125 ((125)IPD) and its authentic compound labeled with iodine-127 (IPD) have been synthesized, purified, and characterized. The alkaline phosphatase (ALP)-mediated conversion of these water-soluble nonfluorescent prodrugs to the water-insoluble fluorescent species, iodine-125-labeled 2-(2'-hydroxyphenyl)-6-iodo-4-(3H)-quinazolinone ((125)ID) and its iodine-127-labeled derivative (ID), has been demonstrated in vitro. Biodistribution studies in mice indicate that both (125)IPD and (125)ID are minimally retained by most tissues and organs. In addition, following its intravenous injection in mice, (125)IPD is localized in ALP-rich regions and converted to (125)ID, which remains indefinitely within the tissues where it is produced. We believe that EMIT is a strategy that will lead to the active and specific concentration and entrapment of therapeutic radionuclides within solid tumors, the consequent protracted irradiation of tumor cells within the range of the emitted particles, and the effective therapy of solid tumors.
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Affiliation(s)
- Nan-hui Ho
- Department of Radiology, Harvard Medical School, Goldenson Building B-242, 220 Longwood Avenue, Boston, Massachusetts 02115, USA
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Abstract
When asked, in 1936 by J. Howard Means, Chief of Medicine at Massachusetts General Hospital, whether radioiodine could be produced for thyroid studies, Karl T. Compton, President of the Massachusetts Institute of Technology, referred the question to Robley Evans of the physics department. In response, Evans formed a team from the fields of physics and medicine that produced 128I for animal studies and, subsequently on a cyclotron dedicated to medical purposes, 130I for human uptake measurements and the treatment of hyperthyroidism. Much of what we have learned about iodine kinetics and the radioiodine therapy of Graves's disease stems from these early seminal reports. The cooperation between physicists and physicians that made their accomplishments possible stands as a model example for interdisciplinary collaboration.
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Affiliation(s)
- S J Adelstein
- Daniel C. Tosteson University Professor, Harvard Medical School, 220 Longwood Avenue-Goldenson 242, Boston, MA 02115, USA
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Abstract
PURPOSE To address the cytotoxic effects of DNA-incorporated (125)I in Chinese hamster V79 lung fibroblasts under various scavenging conditions. METHODS The toxic effects of DNA-incorporated 5-[(125)I]iodo-2'-deoxyuridine ((125)IdUrd) were assessed by the colony-forming assay with cells incubated in medium containing serum and/or dimethyl sulphoxide (DMSO). Experiments were carried out at 0.3 or -135 degrees C. RESULTS When (125)I decays were accumulated at 0.3 degrees C in 10% serum 0, 5 or 10% DMSO, no radioprotection was afforded by 5% DMSO, while the dose modification factor (DMF) for 10% DMSO was 2.0. For cells accumulating decays at 135 degrees C in the presence of 5 or 10% serum, DMSO was radioprotective (DMF= 1.8-1.9). D(0) obtained at each serum concentration correlated strongly (R=0.999) with the scavenging capacity of DMSO. Under these experimental conditions, 10% serum is approximately 3.6 times more protective than 5% serum. CONCLUSIONS The contribution of indirect mechanisms to the toxicity of (125)I decaying within mammalian cell nuclear DNA can be demonstrated not only with DMSO, but also with the hydroxy radical scavengers present in serum.
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Affiliation(s)
- M A Walicka
- Department of Radiology, Harvard Medical School, Boston, MA 02115, USA
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Adelstein SJ. The 2000 NCRP Lauriston S. Taylor lecture--administered radioactivity: unde venimus quoque imus. National Council on Radiation Protection and Measurements. Health Phys 2001; 80:317-324. [PMID: 11281198 DOI: 10.1097/00004032-200104000-00003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
In this lecture, which celebrates Lauriston S. Taylor, a pioneer in radiation protection and founding president of the NCRP, I review some features of medically administered radioactivity through the past century and attempt to forecast some aspects of its future. I have used as my guide NCRP Report No. 70, Nuclear Medicine--Factors Influencing the Choice and Use of Radionuclides in Diagnosis and Therapy. The following topics are addressed: (1) decision-making considerations in the choice of radiopharmaceutical drug products, (2) factors in choosing an instrument for nuclear medicine procedures, (3) radiation dose, (4) evaluation of radionuclide procedures and their clinical utility, and (5) guidelines for performing nuclear medicine procedures.
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