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Ding Y, Tong Z, Jin L, Ye B, Zhou J, Sun Z, Yang H, Hong L, Huang F, Wang W, Mao Z. An NIR Discrete Metallacycle Constructed from Perylene Bisimide and Tetraphenylethylene Fluorophores for Imaging-Guided Cancer Radio-Chemotherapy. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2106388. [PMID: 34821416 DOI: 10.1002/adma.202106388] [Citation(s) in RCA: 71] [Impact Index Per Article: 35.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2021] [Revised: 10/17/2021] [Indexed: 06/13/2023]
Abstract
To promote the clinical theranostic performances of platinum-based anticancer drugs, imaging capability is urgently desired, and their chemotherapeutic efficacy needs to be upgraded. Herein, a theranostic metallacycle (M) is developed for imaging-guided cancer radio-chemotherapy using perylene bisimide fluorophore (PPy) and tetraphenylethylene-based di-Pt(II) organometallic precursor (TPE-Pt) as building blocks. The formation of this discrete supramolecular coordination complex facilitates the encapsulation of M by a glutathione (GSH)-responsive amphiphilic block copolymer to prepare M-loaded nanoparticles (MNPs). TPE-Pt acts as a chemotherapeutic drug and also an excellent radiosensitizer, thus incorporating radiotherapy into the nanomedicine to accelerate the therapeutic efficacy and overcome drug resistance. The NIR-emission of PPy is employed to detect the intracellular delivery and tissue distribution of MNPs in real time. In vitro and in vivo investigations demonstrate the excellent anticancer efficacy combining chemotherapy and radiotherapy; the administration of this nanomedicine effectively inhibits the tumor growth and greatly extends the survival rate of cisplatin-resistant A2780CIS-tumor-bearing mice. Guided by in vivo fluorescence imaging, radio-chemotherapy is precisely carried out, which facilitates boosting of the therapeutic outcomes and minimizing undesired side effects. The success of this theranostic system brings new hope to supramolecular nanomedicines for their potential clinical translations.
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Affiliation(s)
- Yuan Ding
- Department of Hepatobiliary and Pancreatic Surgery, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, 310009, China
- Key Laboratory of Precision Diagnosis and Treatment for Hepatobiliary and Pancreatic Tumor of Zhejiang Province, Zhejiang University, Hangzhou, Zhejiang, 310009, China
- Research Center of Diagnosis and Treatment Technology for Hepatocellular Carcinoma of Zhejiang Province, Zhejiang University, Hangzhou, Zhejiang, 310009, China
- Clinical Medicine Innovation Center of Precision Diagnosis and Treatment for Hepatobiliary and Pancreatic Disease of Zhejiang University, Zhejiang University, Hangzhou, Zhejiang, 310009, China
- Clinical Research Center of Hepatobiliary and Pancreatic Diseases of Zhejiang Province, Zhejiang University, Hangzhou, Zhejiang, 310009, China
- Zhejiang University Cancer Center, Zhejiang University, Hangzhou, Zhejiang, 310009, China
| | - Zongrui Tong
- Key Laboratory of Precision Diagnosis and Treatment for Hepatobiliary and Pancreatic Tumor of Zhejiang Province, Zhejiang University, Hangzhou, Zhejiang, 310009, China
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou, Zhejiang, 310027, China
| | - Lulu Jin
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou, Zhejiang, 310027, China
| | - Binglin Ye
- Department of Hepatobiliary and Pancreatic Surgery, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, 310009, China
- Key Laboratory of Precision Diagnosis and Treatment for Hepatobiliary and Pancreatic Tumor of Zhejiang Province, Zhejiang University, Hangzhou, Zhejiang, 310009, China
- Research Center of Diagnosis and Treatment Technology for Hepatocellular Carcinoma of Zhejiang Province, Zhejiang University, Hangzhou, Zhejiang, 310009, China
- Clinical Medicine Innovation Center of Precision Diagnosis and Treatment for Hepatobiliary and Pancreatic Disease of Zhejiang University, Zhejiang University, Hangzhou, Zhejiang, 310009, China
- Clinical Research Center of Hepatobiliary and Pancreatic Diseases of Zhejiang Province, Zhejiang University, Hangzhou, Zhejiang, 310009, China
- Zhejiang University Cancer Center, Zhejiang University, Hangzhou, Zhejiang, 310009, China
| | - Jiong Zhou
- Department of Chemistry, College of Sciences, Northeastern University, Shenyang, 110819, P. R. China
| | - Zhongquan Sun
- Department of Hepatobiliary and Pancreatic Surgery, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, 310009, China
- Key Laboratory of Precision Diagnosis and Treatment for Hepatobiliary and Pancreatic Tumor of Zhejiang Province, Zhejiang University, Hangzhou, Zhejiang, 310009, China
- Research Center of Diagnosis and Treatment Technology for Hepatocellular Carcinoma of Zhejiang Province, Zhejiang University, Hangzhou, Zhejiang, 310009, China
- Clinical Medicine Innovation Center of Precision Diagnosis and Treatment for Hepatobiliary and Pancreatic Disease of Zhejiang University, Zhejiang University, Hangzhou, Zhejiang, 310009, China
- Clinical Research Center of Hepatobiliary and Pancreatic Diseases of Zhejiang Province, Zhejiang University, Hangzhou, Zhejiang, 310009, China
- Zhejiang University Cancer Center, Zhejiang University, Hangzhou, Zhejiang, 310009, China
| | - Huang Yang
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou, Zhejiang, 310027, China
| | - Liangjie Hong
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou, Zhejiang, 310027, China
| | - Feihe Huang
- State Key Laboratory of Chemical Engineering, Key Laboratory of Excited-State Materials of Zhejiang Province, Stoddart Institute of Molecular Science, Department of Chemistry, Zhejiang University, Hangzhou, 310027, China
- ZJU-Hangzhou Global Scientific and Technological Innovation Center, Hangzhou, 311215, China
- Green Catalysis Center and College of Chemistry, Zhengzhou University, Zhengzhou, 450001, China
| | - Weilin Wang
- Department of Hepatobiliary and Pancreatic Surgery, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, 310009, China
- Key Laboratory of Precision Diagnosis and Treatment for Hepatobiliary and Pancreatic Tumor of Zhejiang Province, Zhejiang University, Hangzhou, Zhejiang, 310009, China
- Research Center of Diagnosis and Treatment Technology for Hepatocellular Carcinoma of Zhejiang Province, Zhejiang University, Hangzhou, Zhejiang, 310009, China
- Clinical Medicine Innovation Center of Precision Diagnosis and Treatment for Hepatobiliary and Pancreatic Disease of Zhejiang University, Zhejiang University, Hangzhou, Zhejiang, 310009, China
- Clinical Research Center of Hepatobiliary and Pancreatic Diseases of Zhejiang Province, Zhejiang University, Hangzhou, Zhejiang, 310009, China
- Zhejiang University Cancer Center, Zhejiang University, Hangzhou, Zhejiang, 310009, China
| | - Zhengwei Mao
- Department of Hepatobiliary and Pancreatic Surgery, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, 310009, China
- Key Laboratory of Precision Diagnosis and Treatment for Hepatobiliary and Pancreatic Tumor of Zhejiang Province, Zhejiang University, Hangzhou, Zhejiang, 310009, China
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou, Zhejiang, 310027, China
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Bayo J, Tran TA, Wang L, Peña-Llopis S, Das AK, Martinez ED. Jumonji Inhibitors Overcome Radioresistance in Cancer through Changes in H3K4 Methylation at Double-Strand Breaks. Cell Rep 2019; 25:1040-1050.e5. [PMID: 30355483 PMCID: PMC6245670 DOI: 10.1016/j.celrep.2018.09.081] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Revised: 03/17/2018] [Accepted: 09/25/2018] [Indexed: 01/10/2023] Open
Abstract
We have uncovered a role for Jumonji inhibitors in overcoming radioresistance through KDM5B inhibition. Pharmacological blockade of Jumonji demethy-lases with JIB-04 leads to specific accumulation of H3K4me3 at sites marked by γH2AX and impaired recruitment of DNA repair factors, preventing resolution of damage and resulting in robust sensitization to radiation therapy. In DNA-repair-proficient cancer cells, knockdown of the H3K4me3 demethylase KDM5B, but not other Jumonji enzymes, mimics pharmacological inhibition, and KDM5B overexpression rescues this phenotype and increases radioresistance. The H3K4me3 demethylase inhibitor PBIT also sensitizes cancer cells to radiation, while an H3K27me3 demethylase inhibitor does not. In vivo co-administration of radiation with JIB-04 significantly prolongs the survival of mice with tumors even long after cessation of treatment. In human patients, lung squamous cell carcinomas highly ex-pressing KDM5B respond poorly to radiation. Thus, we propose the use of Jumonji KDM inhibitors as potent radiosensitizers. Radioresistance is an obstacle to lung cancer cures. Bayo et al. reveal that JARID1B removes H3K4me3 marks at sites of DNA damage. Genetic or pharmacological inhibition of JARID1B robustly radiosensitizes cancers in vitro and in vivo through defects in DNA repair, providing a therapeutic option for radioresistant tumors.
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Affiliation(s)
- Juan Bayo
- Department of Pharmacology, UT Southwestern Medical Center, Dallas, TX, USA; Instituto de Investigaciones en Medicina Traslacional, CONICET, Universidad Austral, Argentina
| | - Tram Anh Tran
- Hamon Center for Therapeutic Oncology Research, UT Southwestern Medical Center, Dallas, TX, USA
| | - Lei Wang
- Hamon Center for Therapeutic Oncology Research, UT Southwestern Medical Center, Dallas, TX, USA
| | - Samuel Peña-Llopis
- Division of Translational Oncology, Essen University Hospital, German Cancer Consortium (DKTK), Partner Site Essen and German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Amit K Das
- Hamon Center for Therapeutic Oncology Research, UT Southwestern Medical Center, Dallas, TX, USA
| | - Elisabeth D Martinez
- Department of Pharmacology, UT Southwestern Medical Center, Dallas, TX, USA; Hamon Center for Therapeutic Oncology Research, UT Southwestern Medical Center, Dallas, TX, USA.
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Kim JY, Cho JH, Kim EM, Shin HJ, Hwang SG, Song JY, Um HD, Park JK. β-Apopicropodophyllin functions as a radiosensitizer targeting ER stress in non-small cell lung cancer. Biomed Pharmacother 2019; 113:108769. [PMID: 30870718 DOI: 10.1016/j.biopha.2019.108769] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Revised: 03/07/2019] [Accepted: 03/07/2019] [Indexed: 12/22/2022] Open
Abstract
AIMS In this study, we examined whether β-apopicropodophyllin (APP) could act as a radiosensitizer in non-small cell lung cancer (NSCLC) cells. MAIN METHODS The in vitro radiosensitizing activity of APP was demonstrated with clonogenic assay, immunoblotting, Annexin V-Propidium iodide (PI) assay, BrdU incorporation, detection of mitochondrial ROS/intracellular of H2O2, mitochondrial membrane potential detection, and performing of isolation of mitochondrial and cytosolic fractions. The in vivo radiosensitizing activity of APP was determined in xenografted mice with co-treatment of APP and IR based on measurement of tumor volumes and apoptotic cell death. KEY FINDINGS The results of a clonogenic assay indicated that a combination of APP and γ-ionizing radiation (IR) inhibits cell growth and increases cell death in NSCLC cells. Several signal transduction pathways were examined for their potential involvement in the apparent radiosensitization effect of APP, as assessed by immunoblotting analyses and mitochondrial potential determination in vitro. Treatment of NCI-H460 cells with 15 nM APP and NCI-H1299 cells with 10 nM APP yielded dose-enhancement ratios of 1.44 and 1.24, respectively. Enhanced ER stress, disrupted mitochondrial membrane potential, and increased reactive oxygen species (ROS) were observed in cells co-treated with APP and IR, and this was followed by the cytosolic release of cytochrome c and consequent activation of caspase-3 and -9. Notably, inhibition of JNK, which prevents caspase activation, blocked the APP/IR-induced activations of ER stress and apoptotic cell death. In NCI-H460 or NCI-H1299 cell-xenografted mice, APP/IR treatment delayed the time it took tumors to reach a threshold size by 22.38 and 16.83 days, respectively, compared with controls, to yield enhancement factors of 1.53 and 1.38, respectively. SIGNIFICANCE APP has a radiosensitizing function derived from its ability to induce apoptotic cell death via activation of ER stress, disruption of mitochondrial membrane potential, and induction of the caspase pathway.
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Affiliation(s)
- Ju Yeon Kim
- Division of Applied Radiation Bioscience, Korea Institute of Radiological and Medical Sciences, Seoul, Republic of Korea
| | - Jeong Hyun Cho
- Division of Applied Radiation Bioscience, Korea Institute of Radiological and Medical Sciences, Seoul, Republic of Korea
| | - Eun Mi Kim
- Division of Applied Radiation Bioscience, Korea Institute of Radiological and Medical Sciences, Seoul, Republic of Korea
| | - Hyun-Jin Shin
- Division of Applied Radiation Bioscience, Korea Institute of Radiological and Medical Sciences, Seoul, Republic of Korea
| | - Sang-Gu Hwang
- Division of Applied Radiation Bioscience, Korea Institute of Radiological and Medical Sciences, Seoul, Republic of Korea
| | - Jie-Young Song
- Division of Applied Radiation Bioscience, Korea Institute of Radiological and Medical Sciences, Seoul, Republic of Korea
| | - Hong-Duck Um
- Division of Applied Radiation Bioscience, Korea Institute of Radiological and Medical Sciences, Seoul, Republic of Korea
| | - Jong Kuk Park
- Division of Applied Radiation Bioscience, Korea Institute of Radiological and Medical Sciences, Seoul, Republic of Korea.
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Yang M, Wang H, Zhou M, Liu W, Kuang P, Liang H, Yuan Q. The natural compound sulforaphene, as a novel anticancer reagent, targeting PI3K-AKT signaling pathway in lung cancer. Oncotarget 2018; 7:76656-76666. [PMID: 27765931 PMCID: PMC5363538 DOI: 10.18632/oncotarget.12307] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2015] [Accepted: 09/12/2016] [Indexed: 11/25/2022] Open
Abstract
Lung cancer is one of the leading causes of cancer death worldwide. Isothiocyanates from cruciferous vegetables been shown to possess anticarcinogenic activities in lung malignances. We previously found sulforaphene (4-methylsufinyl-3-butenyl isothiocyanate, SFE), one new kind of isothiocyanates, existing in a relative high abundance in radish seeds. An efficient methodology based on macroporous resin and preparative high-performance liquid chromatography was developed to isolate SFE in reasonably large quantities, high purity and low cost. However, it is still largely unclear whether SFE could function as an antineoplastic compound, especially in lung cancer. In this study, we systematically investigated the anti-cancer effects of SFE in vitro as well as its possible underling molecular mechanisms in lung cancer. The acute toxicity tests and pharmacokinetics tests for SFE were performed to evaluate its drugability in mice. Also, we evaluated the in vivo anti-cancer effects of SFE using nude Balb/C mice with lung cancer xenograft. SFE can induce apoptosis of multiple lung cancer celllines and, thus, inhibited cancer cell proliferation. Lung cancer cells treated with SFE exhibit significant inhibition of the PI3K-AKT signaling pathway, including depressed PTEN expression and inhibition of AKT phosphoralation. At well-tolerated doses, administration of SFE to mice bearing lung cancer xenografts leads to significant inhibitions of tumor growth. In summary, our work identifies SFE as a novel natural broad-spectrum small molecule inhibitor for lung cancer.
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Affiliation(s)
- Ming Yang
- State Key Laboratory of Chemical Resource Engineering, Beijing Laboratory of Biomedical Materials, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, China
| | - Haiyong Wang
- State Key Laboratory of Chemical Resource Engineering, Beijing Laboratory of Biomedical Materials, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, China
| | - Mo Zhou
- State Key Laboratory of Chemical Resource Engineering, Beijing Laboratory of Biomedical Materials, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, China
| | - Weilin Liu
- State Key Laboratory of Chemical Resource Engineering, Beijing Laboratory of Biomedical Materials, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, China
| | - Pengqun Kuang
- State Key Laboratory of Chemical Resource Engineering, Beijing Laboratory of Biomedical Materials, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, China
| | - Hao Liang
- State Key Laboratory of Chemical Resource Engineering, Beijing Laboratory of Biomedical Materials, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, China
| | - Qipeng Yuan
- State Key Laboratory of Chemical Resource Engineering, Beijing Laboratory of Biomedical Materials, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, China
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Deraska PV, O'Leary C, Reavis HD, Labe S, Dinh TK, Lazaro JB, Sweeney C, D'Andrea AD, Kozono D. NF-κB inhibition by dimethylaminoparthenolide radiosensitizes non-small-cell lung carcinoma by blocking DNA double-strand break repair. Cell Death Discov 2018. [PMID: 29531807 PMCID: PMC5841323 DOI: 10.1038/s41420-017-0008-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Despite optimal chemotherapy, radiotherapy (RT), and/or surgery, non-small-cell lung carcinoma (NSCLC) remains the leading cause of cancer-related death in the US and worldwide. Thoracic RT, a mainstay in the treatment of locally advanced NSCLC, is often restricted in efficacy by a therapeutic index limited by sensitivity of tissues surrounding the malignancy. Therefore, radiosensitizers that can improve the therapeutic index are a vital unmet need. Inhibition of the NF-κB pathway is a proposed mechanism of radiosensitization. Here we demonstrate that inhibition of the canonical NF-κB pathway by dimethylaminoparthenolide (DMAPT) radiosensitizes NSCLC by blocking DNA double-strand break (DSB) repair. NF-κB inhibition results in significant impairment of both homologous recombination (HR) and non-homologous end joining (NHEJ), as well as reductions in ionizing radiation (IR)-induced DNA repair biomarkers. NF-κB inhibition by DMAPT shows preclinical potential for further investigation as a NSCLC radiosensitizer.
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Affiliation(s)
- Peter V Deraska
- 1Department of Radiation Oncology, Dana-Farber Cancer Institute, Boston, MA USA
| | - Colin O'Leary
- 1Department of Radiation Oncology, Dana-Farber Cancer Institute, Boston, MA USA
| | - Hunter D Reavis
- 1Department of Radiation Oncology, Dana-Farber Cancer Institute, Boston, MA USA
| | - Shelby Labe
- 1Department of Radiation Oncology, Dana-Farber Cancer Institute, Boston, MA USA
| | - Tru-Khang Dinh
- 1Department of Radiation Oncology, Dana-Farber Cancer Institute, Boston, MA USA
| | - Jean-Bernard Lazaro
- 1Department of Radiation Oncology, Dana-Farber Cancer Institute, Boston, MA USA.,2Center for DNA Damage and Repair, Dana-Farber Cancer Institute, Boston, MA USA
| | - Christopher Sweeney
- 3Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA USA
| | - Alan D D'Andrea
- 1Department of Radiation Oncology, Dana-Farber Cancer Institute, Boston, MA USA.,2Center for DNA Damage and Repair, Dana-Farber Cancer Institute, Boston, MA USA.,4Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA USA
| | - David Kozono
- 1Department of Radiation Oncology, Dana-Farber Cancer Institute, Boston, MA USA
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AMRI-59 functions as a radiosensitizer via peroxiredoxin I-targeted ROS accumulation and apoptotic cell death induction. Oncotarget 2017; 8:114050-114064. [PMID: 29371968 PMCID: PMC5768385 DOI: 10.18632/oncotarget.23114] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Accepted: 11/26/2017] [Indexed: 01/01/2023] Open
Abstract
Previously, we identified AMRI-59 as a specific pharmaceutical inhibitor of peroxiredoxin (PRX) I enzyme activity. In this study, we examined whether AMRI-59 acts as a radiosensitizer in non-small cell lung cancer cells using clonogenic assays. The intracellular mechanisms underlying the radiosensitization effect of AMRI-59 were determined via immunoblotting in addition to measurement of ROS generation, mitochondrial potential and cell death. AMRI-59 activity in vivo was examined by co-treating nude mice with the compound and γ-ionizing radiation (IR), followed by measurement of tumor volumes and apoptosis. The dose enhancement ratios of 30 μM AMRI-59 in NCI-H460 and NCI-H1299 were 1.51 and 2.12, respectively. Combination of AMRI-59 with IR augmented ROS production and mitochondrial potential disruption via enhancement of PRX I oxidation, leading to increased expression of γH2AX, a DNA damage marker, and suppression of ERK phosphorylation, and finally, activation of caspase-3. Notably, inhibition of ROS production prevented ERK suppression, and blockage of ERK in combination with AMRI-59 and IR led to enhanced caspase-3 activation and apoptosis. In a xenograft assay using NCI-H460 and NCI-H1299, combined treatment with AMRI-59 and IR delayed tumor growth by 26.98 and 14.88 days, compared with controls, yielding enhancement factors of 1.73 and 1.37, respectively. Taken together, the results indicate that AMRI-59 functions as a PRX I-targeted radiosensitizer by inducing apoptosis through activation of the ROS/γH2AX/caspase pathway and suppression of ERK.
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Wu CT, Motegi A, Motegi K, Hotta K, Kohno R, Tachibana H, Kumagai M, Nakamura N, Hojo H, Niho S, Goto K, Akimoto T. Dosimetric comparison between proton beam therapy and photon radiation therapy for locally advanced non-small cell lung cancer. Jpn J Clin Oncol 2016; 46:1008-1014. [PMID: 27511988 DOI: 10.1093/jjco/hyw108] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Revised: 06/07/2016] [Accepted: 06/17/2016] [Indexed: 12/25/2022] Open
Abstract
OBJECTIVE To assess the feasibility of proton beam therapy for the patients with locally advanced non-small lung cancer. METHODS The dosimetry was analyzed retrospectively to calculate the doses to organs at risk, such as the lung, heart, esophagus and spinal cord. A dosimetric comparison between proton beam therapy and dummy photon radiotherapy (three-dimensional conformal radiotherapy) plans was performed. Dummy intensity-modulated radiotherapy plans were also generated for the patients for whom curative three-dimensional conformal radiotherapy plans could not be generated. RESULTS Overall, 33 patients with stage III non-small cell lung cancer were treated with proton beam therapy between December 2011 and August 2014. The median age of the eligible patients was 67 years (range: 44-87 years). All the patients were treated with chemotherapy consisting of cisplatin/vinorelbine or carboplatin. The median prescribed dose was 60 GyE (range: 60-66 GyE). The mean normal lung V20 GyE was 23.6% (range: 14.9-32%), and the mean normal lung dose was 11.9 GyE (range: 6.0-19 GyE). The mean esophageal V50 GyE was 25.5% (range: 0.01-63.6%), the mean heart V40 GyE was 13.4% (range: 1.4-29.3%) and the mean maximum spinal cord dose was 40.7 GyE (range: 22.9-48 GyE). Based on dummy three-dimensional conformal radiotherapy planning, 12 patients were regarded as not being suitable for radical thoracic three-dimensional conformal radiotherapy. All the dose parameters of proton beam therapy, except for the esophageal dose, were lower than those for the dummy three-dimensional conformal radiotherapy plans. In comparison to the intensity-modulated radiotherapy plan, proton beam therapy also achieved dose reduction in the normal lung. None of the patients experienced grade 4 or worse non-hematological toxicities. CONCLUSIONS Proton beam therapy for patients with stage III non-small cell lung cancer was feasible and was superior to three-dimensional conformal radiotherapy for several dosimetric parameters.
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Affiliation(s)
- Chen-Ta Wu
- Division of Radiation Oncology and Particle Therapy, National Cancer Center Hospital East , Kashiwa, Chiba, Japan.,Department of Radiation Oncology, Buddhist Tzu-Chi General Hospital, Hualien, Taiwan
| | - Atsushi Motegi
- Division of Radiation Oncology and Particle Therapy, National Cancer Center Hospital East , Kashiwa, Chiba, Japan
| | - Kana Motegi
- Division of Radiation Oncology and Particle Therapy, National Cancer Center Hospital East , Kashiwa, Chiba, Japan
| | - Kenji Hotta
- Division of Radiation Oncology and Particle Therapy, National Cancer Center Hospital East , Kashiwa, Chiba, Japan
| | - Ryosuke Kohno
- Division of Radiation Oncology and Particle Therapy, National Cancer Center Hospital East , Kashiwa, Chiba, Japan
| | - Hidenobu Tachibana
- Division of Radiation Oncology and Particle Therapy, National Cancer Center Hospital East , Kashiwa, Chiba, Japan
| | - Motoki Kumagai
- Division of Radiation Oncology and Particle Therapy, National Cancer Center Hospital East , Kashiwa, Chiba, Japan
| | - Naoki Nakamura
- Division of Radiation Oncology and Particle Therapy, National Cancer Center Hospital East , Kashiwa, Chiba, Japan
| | - Hidehiro Hojo
- Division of Radiation Oncology and Particle Therapy, National Cancer Center Hospital East , Kashiwa, Chiba, Japan
| | - Seiji Niho
- Department of Thoracic Oncology, National Cancer Center Hospital East, Kashiwa, Chiba, Japan
| | - Koichi Goto
- Department of Thoracic Oncology, National Cancer Center Hospital East, Kashiwa, Chiba, Japan
| | - Tetsuo Akimoto
- Division of Radiation Oncology and Particle Therapy, National Cancer Center Hospital East , Kashiwa, Chiba, Japan
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Brunner TB. The rationale of combined radiotherapy and chemotherapy - Joint action of Castor and Pollux. Best Pract Res Clin Gastroenterol 2016; 30:515-28. [PMID: 27644901 DOI: 10.1016/j.bpg.2016.07.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Accepted: 07/09/2016] [Indexed: 01/31/2023]
Abstract
This article aims to review the rationale behind the combination of radiotherapy and chemotherapy. Theoretical concepts describing the principles of the joint effects of chemoradiotherapy are reviewed. Preclinical and clinical evidence are collected and summarised demonstrating the co-operation between the two modalities which form the mainstay of the treatment of most solid tumours. Initially, the evolution of chemoradiotherapy was mostly empirically driven which is true for both, the early studies and the experimental investigations, rather than relying on scientific rationale. To date, the revised Steel's model proposes five mechanisms, spatial cooperation, cytotoxic enhancement, biological co-operation, temporary modulation and normal tissue protection to describe the interaction between radiotherapy and chemotherapy. Chemoradiotherapy has become the standard modality for most patients with locally advanced solid tumours due to better control of loco-regional disease and prolonged survival. Gradually, molecular prediction of efficacy is integrated such as MGMT status for combining temozolomide with radiotherapy in glioblastoma. As molecular targeted drugs are ready to be taken into triple combinations with chemoradiotherapy it is crucial to have a good understanding of the mechanisms of chemoradiotherapy for the rational development of future combinations.
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Affiliation(s)
- Thomas B Brunner
- Department of Radiation Oncology, University Medical Center Freiburg, Robert-Koch-Str. 3, Freiburg, Germany; German Cancer Consortium (DKTK), Freiburg, Germany.
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Tian X, Lara H, Wagner KT, Saripalli S, Hyder SN, Foote M, Sethi M, Wang E, Caster JM, Zhang L, Wang AZ. Improving DNA double-strand repair inhibitor KU55933 therapeutic index in cancer radiotherapy using nanoparticle drug delivery. NANOSCALE 2015; 7:20211-9. [PMID: 26575637 PMCID: PMC4664156 DOI: 10.1039/c5nr05869d] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Radiotherapy is a key component of cancer treatment. Because of its importance, there has been high interest in developing agents and strategies to further improve the therapeutic index of radiotherapy. DNA double-strand repair inhibitors (DSBRIs) are among the most promising agents to improve radiotherapy. However, their clinical translation has been limited by their potential toxicity to normal tissue. Recent advances in nanomedicine offer an opportunity to overcome this limitation. In this study, we aim to demonstrate the proof of principle by developing and evaluating nanoparticle (NP) formulations of KU55933, a DSBRI. We engineered a NP formulation of KU55933 using nanoprecipitation method with different lipid polymer nanoparticle formulation. NP KU55933 using PLGA formulation has the best loading efficacy as well as prolonged drug release profile. We demonstrated that NP KU55933 is a potent radiosensitizer in vitro using clonogenic assay and is more effective as a radiosensitizer than free KU55933 in vivo using mouse xenograft models of non-small cell lung cancer (NSCLC). Western blots and immunofluorescence showed NP KU55933 exhibited more prolonged inhibition of DNA repair pathway. In addition, NP KU55933 leads to lower skin toxicity than KU55933. Our study supports further investigations using NP to deliver DSBRIs to improve cancer radiotherapy treatment.
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Affiliation(s)
- Xi Tian
- Laboratory of Nano- and Translational Medicine, Department of Radiation Oncology, Carolina Institute of Nanomedicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
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Kuo WT, Tsai YC, Wu HC, Ho YJ, Chen YS, Yao CH, Yao CH. Radiosensitization of non-small cell lung cancer by kaempferol. Oncol Rep 2015; 34:2351-6. [PMID: 26323894 DOI: 10.3892/or.2015.4204] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Accepted: 06/24/2015] [Indexed: 11/06/2022] Open
Abstract
The aim of the present study was to determine whether kaempferol has a radiosensitization potential for lung cancer in vitro and in vivo. The in vitro radio-sensitization activity of kaempferol was elucidated in A-549 lung cancer cells by using an MTT (3-(4 5-dimethylthiazol-2-yl)-25-diphenyl-tetrazolium bromide) assay, cell cycle analysis and clonogenic assay. The in vivo activity was evaluated in the BALB/c nude mouse xenograft model of A-549 cells by hematoxylin and eosin staining and immunohistochemistry, and the tumor volume was recorded. Protein levels of the apoptotic pathway were detected by western blot analysis. Treatment with kaempferol inhibited the growth of A-549 cells through activation of apoptotic pathway. However, the same doses did not affect HFL1 normal lung cell growth. Kaempferol induced G2/M cell cycle arrest and the enhancement of radiation-induced death and clonogenic survival inhibition. The in vivo data showed that kaempferol increased tumor cell apoptosis and killing of radiation. In conclusion, the findings demonstrated that kaempferol increased tumor cell killing by radiation in vitro and in vivo through inhibition of the AKT/PI3K and ERK pathways and activation of the mitochondria apoptosis pathway. The results of the present study provided solid evidence that kaempferol is a safe and potential radiosensitizer.
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Affiliation(s)
- Wei-Ting Kuo
- Institute of Biomedical Engineering, National Taiwan University, Taipei 10051, Taiwan, R.O.C
| | - Yuan-Chung Tsai
- Graduate Institute of Clinical Medical Science, China Medical University, Taichung 40402, Taiwan, R.O.C
| | - His-Chin Wu
- School of Medicine, China Medical University, Taichung 40402, Taiwan, R.O.C
| | - Yung-Jen Ho
- Department of Biomedical Imaging and Radiological Science, China Medical University, Taichung 40402, Taiwan, R.O.C
| | - Yueh-Sheng Chen
- Department of Biomedical Imaging and Radiological Science, China Medical University, Taichung 40402, Taiwan, R.O.C
| | - Chen-Han Yao
- Viator Catholic High School, Taichung 40402, Taiwan, R.O.C
| | - Chun-Hsu Yao
- Department of Biomedical Imaging and Radiological Science, China Medical University, Taichung 40402, Taiwan, R.O.C
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11
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Wang L, Li X, Song YM, Wang B, Zhang FR, Yang R, Wang HQ, Zhang GJ. Ginsenoside Rg3 sensitizes human non-small cell lung cancer cells to γ-radiation by targeting the nuclear factor-κB pathway. Mol Med Rep 2015; 12:609-14. [PMID: 25738799 DOI: 10.3892/mmr.2015.3397] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2014] [Accepted: 01/21/2015] [Indexed: 11/05/2022] Open
Abstract
At present, it is elusive how non-small cell lung cancer (NSCLC) develops resistance to γ-radiation; however, the transcription factor nuclear factor-κB (NF-κB) and NF-κB-regulated gene products have been proposed as mediators. Ginsenoside Rg3 is a steroidal saponin, which was isolated from Panax ginseng. Ginsenoside Rg3 possesses high pharmacological activity and has previously been shown to suppress NF-κB activation in various types of tumor cell. Therefore, the present study aimed to determine whether Rg3 could suppress NF-κB activation in NSCLC cells and sensitize NSCLC to γ-radiation, using an NSCLC cell line and NSCLC xenograft. A clone formation assay and lung tumor xenograft experiment were used to assess the radiosensitizing effects of ginsenoside Rg3. NF-κB/inhibitor of NF-κB (IκB) modulation was ascertained using an electrophoretic mobility shift assay and western blot analysis. NF-κB-regulated gene products were monitored by western blot analysis. The present study demonstrated that ginsenoside Rg3 was able to sensitize A549 and H1299 lung carcinoma cells to γ-radiation and significantly enhance the efficacy of radiation therapy in C57BL/6 mice bearing a Lewis lung carcinoma cell xenograft tumor. Furthermore, ginsenoside Rg3 suppressed NF-κB activation, phosphorylation of IκB protein and expression of NF-κB-regulated gene products (cyclin D1, c-myc, B-cell lymphoma 2, cyclooxygenase-2, matrix metalloproteinase-9 and vascular endothelial growth factor), a number of which were induced by radiation therapy and mediate radioresistance. In conclusion, the results of the present study suggested that ginsenoside Rg3 may potentiate the antitumor effects of radiation therapy in NSCLC by suppressing NF-κB activity and NF-κB-regulated gene products, leading to the inhibition of tumor progression.
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Affiliation(s)
- Lei Wang
- Department of Respiratory Medicine, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan 450052, P.R. China
| | - Xiankui Li
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Tianjin Medical University, Tianjin 300060, P.R. China
| | - Yi-Min Song
- Department of Pathology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan 450052, P.R. China
| | - Bin Wang
- Department of Orthopedics, General Hospital of Pingdingshan Shenma Medical Group, Pingdingshan, Henan 467000, P.R. China
| | - Fu-Rui Zhang
- Department of Respiratory Medicine, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan 450052, P.R. China
| | - Rui Yang
- Department of Respiratory Medicine, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan 450052, P.R. China
| | - Hua-Qi Wang
- Department of Respiratory Medicine, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan 450052, P.R. China
| | - Guo-Jun Zhang
- Department of Respiratory Medicine, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan 450052, P.R. China
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12
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Gomez D, Liao Z, Saintigny P, Komaki RU. Combinations of Radiation Therapy and Chemotherapy for Non-Small Cell and Small-Cell Lung Carcinoma. Lung Cancer 2014. [DOI: 10.1002/9781118468791.ch23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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13
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Wang L, Yang W, Read P, Larner J, Sheng K. Tumor cell apoptosis induced by nanoparticle conjugate in combination with radiation therapy. NANOTECHNOLOGY 2010; 21:475103. [PMID: 21030759 DOI: 10.1088/0957-4484/21/47/475103] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Semiconductor nanoparticles conjugated to photosensitizers have been shown to increase tumor cell death with ionizing radiation but the mechanism, particularly the role of photodynamic therapy in the process, was unknown. We used a molecular probe to measure production of (1)O(2) to quantify the component of photodynamic cell-killing in an in vitro system. The intracellular distribution of the nanoparticle conjugate (NC) was determined by the co-localization of nanoparticles and the lysotracker. Induction of apoptosis was measured by the TUNEL assay and western blot analysis of the cleaved caspase-3. As a result, dose-dependent (1)O(2) production was observed with 48 nm NC after irradiating with 6 MV x-rays. A high geometrical coincidence between the fluorescence emission of the nanoparticle and lysotracker was observed using confocal microscopy. Finally, apoptosis, as indicated by the TUNEL stain and cleavage of the caspase-3, was observed in cells treated by both the NC and 6 Gy of radiation but not in cells treated with radiation alone. In conclusion, the cell death induced by the NC in combination with radiation is consistent with a supra-additive effect to radiation-or NC-alone-killing and is mediated by an NC-induced photodynamic therapy mechanism, which is distinctly different from that for radiation-killing alone. By providing a second distinct cell-killing mechanism, this nanoparticle conjugate has great promise as a targeted physical radiosensitizer aimed at overcoming radioresistant tumor clonogens or/and reducing normal tissue toxicity by using a lower ionizing radiation dose.
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Affiliation(s)
- Li Wang
- Department of Radiation Oncology, University of Virginia, Virginia, USA
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14
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Alexander BM, Othus M, Caglar HB, Allen AM. Tumor volume is a prognostic factor in non-small-cell lung cancer treated with chemoradiotherapy. Int J Radiat Oncol Biol Phys 2010; 79:1381-7. [PMID: 20605346 DOI: 10.1016/j.ijrobp.2009.12.060] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2009] [Revised: 10/26/2009] [Accepted: 12/22/2009] [Indexed: 11/19/2022]
Abstract
PURPOSE To investigate whether primary tumor and nodal volumes defined on radiotherapy planning scans are correlated with outcome (survival and recurrence) after combined-modality treatment. METHODS AND MATERIALS A retrospective review of patients with Stage III non-small-cell lung cancer treated with chemoradiation at Brigham and Women's Hospital/Dana-Farber Cancer Institute from 2000 to 2006 was performed. Tumor and nodal volume measurements, as computed by Eclipse (Varian, Palo Alto, CA), were used as independent variables, along with existing clinical factors, in univariate and multivariate analyses for association with outcomes. RESULTS For patients treated with definitive chemoradiotherapy, both nodal volume (hazard ratio [HR], 1.09; p < 0.01) and tumor volume (HR, 1.03; p < 0.01) were associated with overall survival on multivariate analysis. Both nodal volume (HR, 1.10; p < 0.01) and tumor volume (HR, 1.04; p < 0.01) were also associated with local control but not distant metastases. CONCLUSIONS In addition to traditional surgical staging variables, disease burden, measured by primary tumor and nodal metastases volume, provides information that may be helpful in determining prognosis and identifying groups of patients for which more aggressive local therapy is warranted.
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Affiliation(s)
- Brian M Alexander
- Harvard Radiation Oncology Program, Harvard Medical School, Boston, MA, USA
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15
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Pöttgen C, Eberhardt WE, Gauler T, Krbek T, Berkovic K, Jawad JA, Korfee S, Teschler H, Stamatis G, Stuschke M. Intensified High-Dose Chemoradiotherapy With Induction Chemotherapy in Patients With Locally Advanced Non–Small-Cell Lung Cancer—Safety and Toxicity Results Within a Prospective Trial. Int J Radiat Oncol Biol Phys 2010; 76:809-15. [DOI: 10.1016/j.ijrobp.2009.02.022] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2008] [Revised: 01/13/2009] [Accepted: 02/10/2009] [Indexed: 11/16/2022]
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16
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Affiliation(s)
- Wilfried E E Eberhardt
- Department of Medicine (Cancer Research), West German Tumor Centre, University Hospital of University Duisburg-Essen, Essen, Germany
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17
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Anraku M, Waddell TK, de Perrot M, Lewis SJ, Pierre AF, Darling GE, Johnston MR, Zener RE, Rampersaud YR, Shepherd FA, Leighl N, Bezjak A, Sun AY, Hwang DM, Tsao MS, Keshavjee S. Induction chemoradiotherapy facilitates radical resection of T4 non–small cell lung cancer invading the spine. J Thorac Cardiovasc Surg 2009; 137:441-447.e1. [DOI: 10.1016/j.jtcvs.2008.09.035] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2007] [Revised: 08/27/2008] [Accepted: 09/14/2008] [Indexed: 10/21/2022]
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18
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Investigating Effective Combinations of Anti-cancer Drugs and Radiation Therapy for Treating Non-small Cell Lung Cancer with Using Two Cell Lines. ACTA ACUST UNITED AC 2009. [DOI: 10.6058/jlc.2009.8.1.21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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19
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Widesott L, Amichetti M, Schwarz M. Proton therapy in lung cancer: clinical outcomes and technical issues. A systematic review. Radiother Oncol 2008; 86:154-64. [PMID: 18241945 DOI: 10.1016/j.radonc.2008.01.003] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2007] [Revised: 01/03/2008] [Accepted: 01/03/2008] [Indexed: 12/25/2022]
Abstract
BACKGROUND AND PURPOSE To determine whether, according to the currently available literature, proton therapy (PT) has a role in the treatment of non-small-cell lung cancer (NSCLC), to assess its safety and efficacy and to evaluate the main technical issues specifically related to this treatment technique. MATERIALS AND METHODS During March 2007, two independent researchers conducted a systematic review of the current data on the treatment of NSCLC with PT. RESULTS In total, 113 reports were retrieved, 17 of which were included in the analysis. There were no prospective trials (randomized or non-randomized). Nine uncontrolled single-arm studies were available from three PT centers, providing clinical outcomes for 214 patients in total. These reports were mainly related to stage I-II tumors, with results comparable to those obtained with surgery, without significant toxicity. In addition, two papers were found that compared photon and proton dose distributions, which showed a potential for dose escalation and/or a sparing of the organ at risk with PT. Finally, six studies analyzed dosimetric and technical issues related with PT, mainly underlining the difficulties in designing dose distributions that are representative of the dose actually delivered during treatment. CONCLUSIONS Although from a physical point of view PT is a good option for the treatment of NSCLC, limited data are available on its application in the clinical practice. Furthermore, the application of PT to lung cancer does present technical challenges. Because of the small number of institutions involved in the treatment of this disease, number of patients, and methodological weaknesses of the trials it is therefore not possible to draw definitive conclusions about the superiority of PT with respect to the photon techniques currently available for the treatment of NSCLC.
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Wardman P. Chemical radiosensitizers for use in radiotherapy. Clin Oncol (R Coll Radiol) 2007; 19:397-417. [PMID: 17478086 DOI: 10.1016/j.clon.2007.03.010] [Citation(s) in RCA: 317] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2007] [Accepted: 03/13/2007] [Indexed: 12/21/2022]
Abstract
Radiosensitizers are intended to enhance tumour cell killing while having much less effect on normal tissues. Some drugs target different physiological characteristics of the tumour, particularly hypoxia associated with radioresistance. Oxygen is the definitive hypoxic cell radiosensitizer, the large differential radiosensitivity of oxic vs hypoxic cells being an attractive factor. The combination of nicotinamide to reduce acute hypoxia with normobaric carbogen breathing is showing clinical promise. 'Electron-affinic' chemicals that react with DNA free radicals have the potential for universal activity to combat hypoxia-associated radioresistance; a nitroimidazole, nimorazole, is clinically effective at tolerable doses. Hypoxia-specific cytotoxins, such as tirapazamine, are valuable adjuncts to radiotherapy. Nitric oxide is a potent hypoxic cell radiosensitizer; variations in endogenous levels might have prognostic significance, and routes to deliver nitric oxide specifically to tumours are being developed. In principle, many drugs can be delivered selectively to hypoxic tumours using either reductase enzymes or radiation-produced free radicals to activate drug release from electron-affinic prodrugs. A redox-active agent based on a gadolinium chelate is being evaluated clinically. Pyrimidines substituted with bromine or iodine are incorporated into DNA and enhance free radical damage; fluoropyrimidines act by different mechanisms. A wide variety of drugs that influence the nature or repair of DNA damage are being evaluated in conjunction with radiation; it is often difficult to define the mechanisms underlying chemoradiation regimens. Drugs being evaluated include topoisomerase inhibitors (e.g. camptothecin, topotecan), and the hypoxia-activated anthraquinone AQ4N; alkylating agents include temozolomide. Drugs involved in DNA repair pathways being investigated include the potent poly(ADP ribose)polymerase inhibitor, AG14,361. Proteins involved in cell signalling, such as the Ras family, are attractive targets linked to radioresistance, as are epidermal growth factor receptors and linked kinases (drugs including vandetanib [ZD6,474], cetuximab and gefitinib), and cyclooxygenase-2 (celecoxib). The suppression of radioprotective thiols seems to offer more potential with alkylating agents than with radiotherapy, although it remains a strategy worthy of exploration.
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Affiliation(s)
- P Wardman
- University of Oxford, Gray Cancer Institute, PO Box 100, Mount Vernon Hospital, Northwood HA6 2JR, UK.
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