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Zarghami N, Murrell DH, Jensen MD, Dick FA, Chambers AF, Foster PJ, Wong E. Half brain irradiation in a murine model of breast cancer brain metastasis: magnetic resonance imaging and histological assessments of dose-response. Radiat Oncol 2018; 13:104. [PMID: 29859114 PMCID: PMC5984731 DOI: 10.1186/s13014-018-1028-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2017] [Accepted: 04/13/2018] [Indexed: 01/09/2023] Open
Abstract
Background Brain metastasis is becoming increasingly prevalent in breast cancer due to improved extra-cranial disease control. With emerging availability of modern image-guided radiation platforms, mouse models of brain metastases and small animal magnetic resonance imaging (MRI), we examined brain metastases’ responses from radiotherapy in the pre-clinical setting. In this study, we employed half brain irradiation to reduce inter-subject variability in metastases dose-response evaluations. Methods Half brain irradiation was performed on a micro-CT/RT system in a human breast cancer (MDA-MB-231-BR) brain metastasis mouse model. Radiation induced DNA double stranded breaks in tumors and normal mouse brain tissue were quantified using γ-H2AX immunohistochemistry at 30 min (acute) and 11 days (longitudinal) after half-brain treatment for doses of 8, 16 and 24 Gy. In addition, tumor responses were assessed volumetrically with in-vivo longitudinal MRI and histologically for tumor cell density and nuclear size. Results In the acute setting, γ-H2AX staining in tumors saturated at higher doses while normal mouse brain tissue continued to increase linearly in the phosphorylation of H2AX. While γ-H2AX fluorescence intensities returned to the background level in the brain 11 days after treatment, the residual γ-H2AX phosphorylation in the radiated tumors remained elevated compared to un-irradiated contralateral tumors. With radiation, MRI-derived relative tumor growth was significantly reduced compared to the un-irradiated side. While there was no difference in MRI tumor volume growth between 16 and 24 Gy, there was a significant reduction in tumor cell density from histology with increasing dose. In the longitudinal study, nuclear size in the residual tumor cells increased significantly as the radiation dose was increased. Conclusions Radiation damages to the DNAs in the normal brain parenchyma are resolved over time, but remain unrepaired in the treated tumors. Furthermore, there is a radiation dose response in nuclear size of surviving tumor cells. Increase in nuclear size together with unrepaired DNA damage indicated that the surviving tumor cells post radiation had continued to progress in the cell cycle with DNA replication, but failed cytokinesis. Half brain irradiation provides efficient evaluation of dose-response for cancer cell lines, a pre-requisite to perform experiments to understand radio-resistance in brain metastases.
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Affiliation(s)
- Niloufar Zarghami
- Department of Medical Biophysics, University of Western Ontario, London, Ontario, Canada
| | - Donna H Murrell
- Department of Medical Biophysics, University of Western Ontario, London, Ontario, Canada.,Imaging Research Laboratories, Robarts Research Institute, London, Ontario, Canada
| | - Michael D Jensen
- Department of Medical Biophysics, University of Western Ontario, London, Ontario, Canada
| | - Frederick A Dick
- Department of Biochemistry, University of Western Ontario, London, Ontario, Canada.,London Regional Cancer Program, University of Western Ontario, London, Ontario, Canada.,Department of Oncology, University of Western Ontario, London, Ontario, Canada
| | - Ann F Chambers
- Department of Medical Biophysics, University of Western Ontario, London, Ontario, Canada.,London Regional Cancer Program, University of Western Ontario, London, Ontario, Canada.,Department of Oncology, University of Western Ontario, London, Ontario, Canada
| | - Paula J Foster
- Department of Medical Biophysics, University of Western Ontario, London, Ontario, Canada.,Imaging Research Laboratories, Robarts Research Institute, London, Ontario, Canada
| | - Eugene Wong
- Department of Medical Biophysics, University of Western Ontario, London, Ontario, Canada. .,London Regional Cancer Program, University of Western Ontario, London, Ontario, Canada. .,Department of Oncology, University of Western Ontario, London, Ontario, Canada. .,Department of Physics and Astronomy, University of Western Ontario, London, Ontario, Canada.
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Gupta SK, Kizilbash SH, Carlson BL, Mladek AC, Boakye-Agyeman F, Bakken KK, Pokorny JL, Schroeder MA, Decker PA, Cen L, Eckel-Passow JE, Sarkar G, Ballman KV, Reid JM, Jenkins RB, Verhaak RG, Sulman EP, Kitange GJ, Sarkaria JN. Delineation of MGMT Hypermethylation as a Biomarker for Veliparib-Mediated Temozolomide-Sensitizing Therapy of Glioblastoma. J Natl Cancer Inst 2016; 108:djv369. [PMID: 26615020 PMCID: PMC4862419 DOI: 10.1093/jnci/djv369] [Citation(s) in RCA: 92] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Revised: 09/23/2015] [Accepted: 10/29/2015] [Indexed: 01/18/2023] Open
Abstract
BACKGROUND Sensitizing effects of poly-ADP-ribose polymerase inhibitors have been studied in several preclinical models, but a clear understanding of predictive biomarkers is lacking. In this study, in vivo efficacy of veliparib combined with temozolomide (TMZ) was evaluated in a large panel of glioblastoma multiforme (GBM) patient-derived xenografts (PDX) and potential biomarkers were analyzed. METHODS The efficacy of TMZ alone vs TMZ/veliparib was compared in a panel of 28 GBM PDX lines grown as orthotopic xenografts (8-10 mice per group); all tests of statistical significance were two-sided. DNA damage was analyzed by γH2AX immunostaining and promoter methylation of DNA repair gene O6-methylguanine-DNA-methyltransferase (MGMT) by Clinical Laboratory Improvement Amendments-approved methylation-specific polymerase chain reaction. RESULTS The combination of TMZ/veliparib statistically significantly extended survival of GBM models (P < .05 by log-rank) compared with TMZ alone in five of 20 MGMT-hypermethylated lines (average extension in median survival = 87 days, range = 20-150 days), while the combination was ineffective in six MGMT-unmethylated lines. In the MGMT promoter-hypermethylated GBM12 line (median survival with TMZ+veliparib = 189 days, 95% confidence interval [CI] = 59 to 289 days, vs TMZ alone = 98 days, 95% CI = 49 to 210 days, P = .04), the profound TMZ-sensitizing effect of veliparib was lost when MGMT was overexpressed (median survival with TMZ+veliparib = 36 days, 95% CI = 28 to 38 days, vs TMZ alone = 35 days, 95% CI = 32 to 37 days, P = .87), and a similar association was observed in two nearly isogenic GBM28 sublines with an intact vs deleted MGMT locus. In comparing DNA damage signaling after dosing with veliparib/TMZ or TMZ alone, increased phosphorylation of damage-responsive proteins (KAP1, Chk1, Chk2, and H2AX) was observed only in MGMT promoter-hypermethylated lines. CONCLUSION Veliparib statistically significantly enhances (P < .001) the efficacy of TMZ in tumors with MGMT promoter hypermethylation. Based on these data, MGMT promoter hypermethylation is being used as an eligibility criterion for A071102 (NCT02152982), the phase II/III clinical trial evaluating TMZ/veliparib combination in patients with GBM.
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Affiliation(s)
- Shiv K Gupta
- Department of Radiation Oncology (SKG, BLC, ACM, KKB, JLP, MAS, LC, GJK, JNS), Division of Medical Oncology (SHK), Molecular Pharmacology and Experimental Therapeutics (FBA, JMR), Division of Biomedical Statistics and Informatics (PAD, JEEP, KVB), and Laboratory Medicine and Pathology (GS, RBJ), Mayo Clinic, Rochester MN; The University of Texas, MD Anderson Cancer Center, Houston, TX (RGV, EPS)
| | - Sani H Kizilbash
- Department of Radiation Oncology (SKG, BLC, ACM, KKB, JLP, MAS, LC, GJK, JNS), Division of Medical Oncology (SHK), Molecular Pharmacology and Experimental Therapeutics (FBA, JMR), Division of Biomedical Statistics and Informatics (PAD, JEEP, KVB), and Laboratory Medicine and Pathology (GS, RBJ), Mayo Clinic, Rochester MN; The University of Texas, MD Anderson Cancer Center, Houston, TX (RGV, EPS)
| | - Brett L Carlson
- Department of Radiation Oncology (SKG, BLC, ACM, KKB, JLP, MAS, LC, GJK, JNS), Division of Medical Oncology (SHK), Molecular Pharmacology and Experimental Therapeutics (FBA, JMR), Division of Biomedical Statistics and Informatics (PAD, JEEP, KVB), and Laboratory Medicine and Pathology (GS, RBJ), Mayo Clinic, Rochester MN; The University of Texas, MD Anderson Cancer Center, Houston, TX (RGV, EPS)
| | - Ann C Mladek
- Department of Radiation Oncology (SKG, BLC, ACM, KKB, JLP, MAS, LC, GJK, JNS), Division of Medical Oncology (SHK), Molecular Pharmacology and Experimental Therapeutics (FBA, JMR), Division of Biomedical Statistics and Informatics (PAD, JEEP, KVB), and Laboratory Medicine and Pathology (GS, RBJ), Mayo Clinic, Rochester MN; The University of Texas, MD Anderson Cancer Center, Houston, TX (RGV, EPS)
| | - Felix Boakye-Agyeman
- Department of Radiation Oncology (SKG, BLC, ACM, KKB, JLP, MAS, LC, GJK, JNS), Division of Medical Oncology (SHK), Molecular Pharmacology and Experimental Therapeutics (FBA, JMR), Division of Biomedical Statistics and Informatics (PAD, JEEP, KVB), and Laboratory Medicine and Pathology (GS, RBJ), Mayo Clinic, Rochester MN; The University of Texas, MD Anderson Cancer Center, Houston, TX (RGV, EPS)
| | - Katrina K Bakken
- Department of Radiation Oncology (SKG, BLC, ACM, KKB, JLP, MAS, LC, GJK, JNS), Division of Medical Oncology (SHK), Molecular Pharmacology and Experimental Therapeutics (FBA, JMR), Division of Biomedical Statistics and Informatics (PAD, JEEP, KVB), and Laboratory Medicine and Pathology (GS, RBJ), Mayo Clinic, Rochester MN; The University of Texas, MD Anderson Cancer Center, Houston, TX (RGV, EPS)
| | - Jenny L Pokorny
- Department of Radiation Oncology (SKG, BLC, ACM, KKB, JLP, MAS, LC, GJK, JNS), Division of Medical Oncology (SHK), Molecular Pharmacology and Experimental Therapeutics (FBA, JMR), Division of Biomedical Statistics and Informatics (PAD, JEEP, KVB), and Laboratory Medicine and Pathology (GS, RBJ), Mayo Clinic, Rochester MN; The University of Texas, MD Anderson Cancer Center, Houston, TX (RGV, EPS)
| | - Mark A Schroeder
- Department of Radiation Oncology (SKG, BLC, ACM, KKB, JLP, MAS, LC, GJK, JNS), Division of Medical Oncology (SHK), Molecular Pharmacology and Experimental Therapeutics (FBA, JMR), Division of Biomedical Statistics and Informatics (PAD, JEEP, KVB), and Laboratory Medicine and Pathology (GS, RBJ), Mayo Clinic, Rochester MN; The University of Texas, MD Anderson Cancer Center, Houston, TX (RGV, EPS)
| | - Paul A Decker
- Department of Radiation Oncology (SKG, BLC, ACM, KKB, JLP, MAS, LC, GJK, JNS), Division of Medical Oncology (SHK), Molecular Pharmacology and Experimental Therapeutics (FBA, JMR), Division of Biomedical Statistics and Informatics (PAD, JEEP, KVB), and Laboratory Medicine and Pathology (GS, RBJ), Mayo Clinic, Rochester MN; The University of Texas, MD Anderson Cancer Center, Houston, TX (RGV, EPS)
| | - Ling Cen
- Department of Radiation Oncology (SKG, BLC, ACM, KKB, JLP, MAS, LC, GJK, JNS), Division of Medical Oncology (SHK), Molecular Pharmacology and Experimental Therapeutics (FBA, JMR), Division of Biomedical Statistics and Informatics (PAD, JEEP, KVB), and Laboratory Medicine and Pathology (GS, RBJ), Mayo Clinic, Rochester MN; The University of Texas, MD Anderson Cancer Center, Houston, TX (RGV, EPS)
| | - Jeanette E Eckel-Passow
- Department of Radiation Oncology (SKG, BLC, ACM, KKB, JLP, MAS, LC, GJK, JNS), Division of Medical Oncology (SHK), Molecular Pharmacology and Experimental Therapeutics (FBA, JMR), Division of Biomedical Statistics and Informatics (PAD, JEEP, KVB), and Laboratory Medicine and Pathology (GS, RBJ), Mayo Clinic, Rochester MN; The University of Texas, MD Anderson Cancer Center, Houston, TX (RGV, EPS)
| | - Gobinda Sarkar
- Department of Radiation Oncology (SKG, BLC, ACM, KKB, JLP, MAS, LC, GJK, JNS), Division of Medical Oncology (SHK), Molecular Pharmacology and Experimental Therapeutics (FBA, JMR), Division of Biomedical Statistics and Informatics (PAD, JEEP, KVB), and Laboratory Medicine and Pathology (GS, RBJ), Mayo Clinic, Rochester MN; The University of Texas, MD Anderson Cancer Center, Houston, TX (RGV, EPS)
| | - Karla V Ballman
- Department of Radiation Oncology (SKG, BLC, ACM, KKB, JLP, MAS, LC, GJK, JNS), Division of Medical Oncology (SHK), Molecular Pharmacology and Experimental Therapeutics (FBA, JMR), Division of Biomedical Statistics and Informatics (PAD, JEEP, KVB), and Laboratory Medicine and Pathology (GS, RBJ), Mayo Clinic, Rochester MN; The University of Texas, MD Anderson Cancer Center, Houston, TX (RGV, EPS)
| | - Joel M Reid
- Department of Radiation Oncology (SKG, BLC, ACM, KKB, JLP, MAS, LC, GJK, JNS), Division of Medical Oncology (SHK), Molecular Pharmacology and Experimental Therapeutics (FBA, JMR), Division of Biomedical Statistics and Informatics (PAD, JEEP, KVB), and Laboratory Medicine and Pathology (GS, RBJ), Mayo Clinic, Rochester MN; The University of Texas, MD Anderson Cancer Center, Houston, TX (RGV, EPS)
| | - Robert B Jenkins
- Department of Radiation Oncology (SKG, BLC, ACM, KKB, JLP, MAS, LC, GJK, JNS), Division of Medical Oncology (SHK), Molecular Pharmacology and Experimental Therapeutics (FBA, JMR), Division of Biomedical Statistics and Informatics (PAD, JEEP, KVB), and Laboratory Medicine and Pathology (GS, RBJ), Mayo Clinic, Rochester MN; The University of Texas, MD Anderson Cancer Center, Houston, TX (RGV, EPS)
| | - Roeland G Verhaak
- Department of Radiation Oncology (SKG, BLC, ACM, KKB, JLP, MAS, LC, GJK, JNS), Division of Medical Oncology (SHK), Molecular Pharmacology and Experimental Therapeutics (FBA, JMR), Division of Biomedical Statistics and Informatics (PAD, JEEP, KVB), and Laboratory Medicine and Pathology (GS, RBJ), Mayo Clinic, Rochester MN; The University of Texas, MD Anderson Cancer Center, Houston, TX (RGV, EPS)
| | - Erik P Sulman
- Department of Radiation Oncology (SKG, BLC, ACM, KKB, JLP, MAS, LC, GJK, JNS), Division of Medical Oncology (SHK), Molecular Pharmacology and Experimental Therapeutics (FBA, JMR), Division of Biomedical Statistics and Informatics (PAD, JEEP, KVB), and Laboratory Medicine and Pathology (GS, RBJ), Mayo Clinic, Rochester MN; The University of Texas, MD Anderson Cancer Center, Houston, TX (RGV, EPS)
| | - Gaspar J Kitange
- Department of Radiation Oncology (SKG, BLC, ACM, KKB, JLP, MAS, LC, GJK, JNS), Division of Medical Oncology (SHK), Molecular Pharmacology and Experimental Therapeutics (FBA, JMR), Division of Biomedical Statistics and Informatics (PAD, JEEP, KVB), and Laboratory Medicine and Pathology (GS, RBJ), Mayo Clinic, Rochester MN; The University of Texas, MD Anderson Cancer Center, Houston, TX (RGV, EPS)
| | - Jann N Sarkaria
- Department of Radiation Oncology (SKG, BLC, ACM, KKB, JLP, MAS, LC, GJK, JNS), Division of Medical Oncology (SHK), Molecular Pharmacology and Experimental Therapeutics (FBA, JMR), Division of Biomedical Statistics and Informatics (PAD, JEEP, KVB), and Laboratory Medicine and Pathology (GS, RBJ), Mayo Clinic, Rochester MN; The University of Texas, MD Anderson Cancer Center, Houston, TX (RGV, EPS).
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