A phase I study of concurrent chemotherapy (paclitaxel and carboplatin) and thoracic radiotherapy with swallowed manganese superoxide dismutase plasmid liposome protection in patients with locally advanced stage III non-small-cell lung cancer

Current status of superoxide dismutase 2 on oral disease progression by supervision of ROS

The recent Global Burden of Disease results have demonstrated that oral diseases are some of the most significant public health challenges facing the world. Owing to its specific localization advantage, superoxide dismutase 2 (SOD2 or MnSOD) has the ability to process the reactive oxygen species (ROS) produced by mitochondrial respiration before anything else, thereby impacting the occurrence and development of diseases. In this review, we summarize the processes of common oral diseases in which SOD2 is involved. SOD2 is upregulated in periodontitis to protect the tissue from the distant damage caused by excessive ROS and further reduce inflammatory progression. SOD2 also participates in the specific pathogenesis of oral cancers and dental diseases. The clinical application prospects of SOD2 in oral diseases will be discussed further, referencing the differences and relationship between oral diseases and other clinical systemic diseases.

Cytokine, chemokine alterations and immune cell infiltration in Radiation-induced lung injury: Implications for prevention and management

Radiation therapy is one of the primary treatments for thoracic malignancies, with radiation-induced lung injury (RILI) emerging as its most prevalent complication. RILI encompasses early-stage radiation pneumonitis (RP) and the subsequent development of radiation pulmonary fibrosis (RPF). During radiation treatment, not only are tumor cells targeted, but normal tissue cells, including alveolar epithelial cells and vascular endothelial cells, also sustain damage. Within the lungs, ionizing radiation boosts the intracellular levels of reactive oxygen species across various cell types. This elevation precipitates the release of cytokines and chemokines, coupled with the infiltration of inflammatory cells, culminating in the onset of RP. This pulmonary inflammatory response can persist, spanning a duration from several months to years, ultimately progressing to RPF. This review aims to explore the alterations in cytokine and chemokine release and the influx of immune cells post-ionizing radiation exposure in the lungs, offering insights for the prevention and management of RILI.

New insights into nanosystems for non-small-cell lung cancer: diagnosis and treatment

Lung cancer is caused by a malignant tumor that shows the fastest growth in both incidence and mortality and is also the greatest threat to human health and life. At present, both in terms of incidence and mortality, lung cancer is the first in male malignant tumors, and the second in female malignant tumors. In the past two decades, research and development of antitumor drugs worldwide have been booming, and a large number of innovative drugs have entered clinical trials and practice. In the era of precision medicine, the concept and strategy of cancer from diagnosis to treatment are experiencing unprecedented changes. The ability of tumor diagnosis and treatment has rapidly improved, the discovery rate and cure rate of early tumors have greatly improved, and the overall survival of patients has benefited significantly, with a tendency to transform to a chronic disease with tumor. The emergence of nanotechnology brings new horizons for tumor diagnosis and treatment. Nanomaterials with good biocompatibility have played an important role in tumor imaging, diagnosis, drug delivery, controlled drug release, etc. This article mainly reviews the advancements in lipid-based nanosystems, polymer-based nanosystems, and inorganic nanosystems in the diagnosis and treatment of non-small-cell lung cancer (NSCLC).

Oral delivery of a highly stable superoxide dismutase as a skin aging inhibitor

As an effective antioxidant enzyme, superoxide dismutase (SOD) has been widely used as a food supplement, cosmetic additive, and therapeutic agent. However, oral delivery of SOD is challenging due to its relative instability, limited bioavailability, and low absorption efficiency in the gastrointestinal (GI) tract. We addressed these issues using a highly stable superoxide dismutase (hsSOD) generated from a hot spring microbial sample. This SOD exhibited a specific activity of 5000 IU/mg while retaining its enzymatic activity under low pH environments of an artificial GI system and in the presence of surfactants and various proteolytic enzymes. The inhibitory effects of hsSOD against skin-aging was evaluated under both in vitro and in vivo experiments using fibroblast cell and D-galactose induced aging-mouse models, respectively. Effective oral delivery of hsSOD promises wide applicability in pharmaceutical and food industries.

Carcinogen 4-Nitroquinoline Oxide (4-NQO) Induces Oncostatin-M (OSM) in Esophageal Cells

BACKGROUND/AIM

The earliest cellular and molecular biologic changes in the esophagus that lead to esophageal cancer were evaluated in a mouse model. We correlated numbers of senescent cells with the levels of expression of potentially carcinogenic genes in sorted side population (SP) cells containing esophageal stem cells and non-stem cells in the non-side population cells in the 4-nitroquinolone oxide (NQO)-treated esophagus.

MATERIALS AND METHODS

We compared stem cells with non-stem cells from the esophagus of mice treated with the chemical carcinogen 4-NQO (100 μg/ml) in drinking water. We also compared gene expression in human esophagus samples treated with 4-NQO (100 μg/ml media) to non-treated samples. We separated and quantitated the relative levels of expression of RNA using RNAseq analysis. We identified senescent cells by luciferase imaging of p16^+/LUC mice and senescent cells in excised esophagus from tdTOMp16+ mice.

RESULTS

A significant increase in the levels of RNA for oncostatin-M was found in senescent cells of the esophagus from 4-NQO-treated mice and human esophagus in vitro.

CONCLUSION

Induction of OSM in chemically-induced esophageal cancer in mice correlates with the appearance of senescent cells.

Gene Therapy for Systemic or Organ Specific Delivery of Manganese Superoxide Dismutase

Manganese superoxide dismutase (MnSOD) is a dominant component of the antioxidant defense system in mammalian cells. Since ionizing irradiation induces profound oxidative stress, it was logical to test the effect of overexpression of MnSOD on radioresistance. This task was accomplished by introduction of a transgene for MnSOD into cells in vitro and into organs in vivo, and both paradigms showed clear radioresistance following overexpression. During the course of development and clinical application of using MnSOD as a radioprotector, several prominent observations were made by Larry Oberley, Joel Greenberger, and Michael Epperly which include (1) mitochondrial localization of either manganese superoxide dismutase or copper/zinc SOD was required to provide optimal radiation protection; (2) the time required for optimal expression was 12-18 h, and while acceptable for radiation protection, the time delay was impractical for radiation mitigation; (3) significant increases in intracellular elevation of MnSOD activity were required for effective radioprotection. Lessons learned during the development of MnSOD gene therapy have provided a strategy for delivery of small molecule SOD mimics, which are faster acting and have shown the potential for both radiation protection and mitigation. The purpose of this review is to summarize the current status of using MnSOD-PL and SOD mimetics as radioprotectors and radiomitigators.

Biology of Radiation-Induced Lung Injury

Radiation-induced lung injury encompasses radiation-induced pneumonitis, inflammation of the lung which may manifest as a dose-limiting acute or subacute toxicity, and radiation-induced lung fibrosis, a late effect of lung exposure to radiation. This review aims to highlight developments in molecular radiation biology of radiation-induced lung injury and their implications in clinical practice.

Superoxide Dismutase as an Intervention for Radiation Therapy-Associated Toxicities: Review and Profile of Avasopasem Manganese as a Treatment Option for Radiation-Induced Mucositis

Toxicities associated with radiation therapy are common, symptomatically devastating, and costly. The best chance to effectively mitigate radiation-associated normal tissue side effects are interventions aimed at disrupting the biological cascade, which is the basis for toxicity development, while simultaneously not reducing the beneficial impact of radiation on tumor. Oxidative stress is a key initiator of radiation-associated normal tissue injury as physiologic antioxidant mechanisms are overwhelmed by the accumulation of effects produced by fractionated treatment regimens. And fundamental to this is the generation of superoxide, which is normally removed by superoxide dismutases (SODs). Attempts to supplement the activity of endogenous SOD to prevent radiation-induced normal tissue injury have included the administration of bovine-derived SOD and increasing SOD production using gene transfer, neither of which has resulted in a clinically acceptable therapy. A third approach has been to develop synthetic small molecule dismutase mimetics. This approach has led to the creation and development of avasopasem manganese, a unique and specific dismutase mimetic that, in clinical trials, has shown promising potential to reduce the incidence, severity and duration of severe oral mucositis amongst patients being treated with concomitant chemoradiation for cancers of the head and neck. Further, avasopasem and related analogues have demonstrated mechanism-related antitumor synergy in combination with high dose per fraction radiotherapy, an observation that is also being tested in clinical trials. An ongoing Phase 3 trial seeks to confirm avasopasem manganese as an effective intervention for severe oral mucositis associated with chemoradiation in head and neck cancer patients.

Decoding the role of SOD2 in sickle cell disease

Sickle cell disease (SCD) is an inherited hemoglobinopathy caused by a single point mutation in the β-globin gene. As a consequence, deoxygenated hemoglobin polymerizes triggering red blood cell sickling and hemolysis, vaso-occlusion, and ischemia/reperfusion. Allied to these pathologies is the overproduction of reactive oxygen species driven by hemoglobin Fenton chemistry and peroxidase reactions as well as by secondary activation of vascular oxidases, including NAD(P)H oxidase and xanthine oxidase. In addition, hypoxia, produced by sickle red blood cell occlusion, disrupts mitochondrial metabolism and generates excess superoxide through electron leak from the mitochondrial respiratory chain. Superoxide dismutase 2 (SOD2) is a mitochondrial-specific antioxidant enzyme that dismutates superoxide to hydrogen peroxide, which is then converted to water by catalase and glutathione peroxidase. In SCD, the antioxidant defense system is significantly diminished through decreased expression and activity levels of antioxidant enzymes, including superoxide dismutase, catalase, and glutathione peroxidase. From a translational perspective, genetic variants including a missense variant in SOD2 (valine to alanine at position 16) are present in 45% of people with African ancestry and are associated with increased sickle complications. While it is known that there is an imbalance between oxidative species and antioxidant defenses in SCD, much more investigation is warranted. This review summarizes our current understanding of antioxidant defense systems in SCD, particularly focused on SOD2, and provides insight into challenges and opportunities as the field moves forward.

Metal ions and the extracellular matrix in tumor migration

In this review, we explore the roles of divalent metal ions in structure and function within the extracellular matrix (ECM), specifically, their interaction with glycosaminoglycans (GAGs) during tumor progression. Metals and GAGs have been individually associated with physiological and pathological processes, however, their combined activities in regulating cell behavior and ECM remodeling have not been fully explored to date. During tumor progression, divalent metals and GAGs participate in central processes, such as cell migration and angiogenesis, either by modulating cell surface molecules, as well as soluble signaling factors. In addition, studies on metals and polysaccharides interactions have been of great value, as they provide structural information that can be correlated with function. Finally, we believe that understanding how metals are regulated in physiological and pathological conditions is paramount for the development of new treatment strategies, as well as diagnostic and exploratory tools.

Gene therapy and cell therapy for the management of radiation damages to healthy tissues: Rationale and early results

Nowadays, ionizing radiations have numerous applications, especially in medicine for diagnosis and therapy. Pharmacological radioprotection aims at increasing detoxification of free radicals. Radiomitigation aims at improving survival and proliferation of damaged cells. Both strategies are essential research area, as non-contained radiation can lead to harmful effects. Some advances allowing the comprehension of normal tissue injury mechanisms, and the discovery of related predictive biomarkers, have led to developing several highly promising radioprotector or radiomitigator drugs. Next to these drugs, a growing interest does exist for biotherapy in this field, including gene therapy and cell therapy through mesenchymal stem cells. In this review article, we provide an overview of the management of radiation damages to healthy tissues via gene or cell therapy in the context of radiotherapy. The early management aims at preventing the occurrence of these damages before exposure or just after exposure. The late management offers promises in the reversion of constituted late damages following irradiation.

Amelioration of Amyotrophic Lateral Sclerosis in SOD1G93A Mice by M2 Microglia from Transplanted Marrow

Background/Aim: The cause of fatal neuromuscular amyotrophic lateral sclerosis (ALS) is not known. Materials and Methods: Ninety-day-old superoxide-dismutase-1 G93A (SOD1 G93A ) mice demonstrating level 1 paralysis, received 9.0 Gy total body irradiation (TBI) from a cesium source at 340 cGy per minute, and intravenous transplantation with 1×10 6 C57BL/6 green fluorescent protein (GFP)+ donor bone marrow cells. Results: Paralysis-free survival was prolonged in TBI and bone marrow-transplanted SOD1 G93A mice from 100 to over 250 days (p=0.0018). Other mice transplanted with SOD1 G93A marrow or marrow treated with the free-radical scavenger MMS350 showed no therapeutic effect. GFP+ macrophage-2 (M2) microglial cells of bone marrow origin, were seen at sites of degenerating anterior horn motor neurons. SOD1 G93A mice had a disruption in the blood-brain barrier permeability which was reversed by marrow transplant from C57BL/6 mice. SOD1 G93A marrow showed unexpected robust hematopoiesis in vitro, and radioresistance. Conclusion: After TBI, M2 microglial cells from transplanted donor marrow extended the paralysis-free interval in SOD1 G93A mice.

Redox manipulation of the manganese metal in human manganese superoxide dismutase for neutron diffraction

Human manganese superoxide dismutase (MnSOD) is one of the most significant enzymes in preventing mitochondrial dysfunction and related diseases by combating reactive oxygen species (ROS) in the mitochondrial matrix. Mitochondria are the source of up to 90% of cellular ROS generation, and MnSOD performs its necessary bioprotective role by converting superoxide into oxygen and hydrogen peroxide. This vital catalytic function is conducted via cyclic redox reactions between the substrate and the active-site manganese using proton-coupled electron transfers. Owing to protons being difficult to detect experimentally, the series of proton transfers that compose the catalytic mechanism of MnSOD are unknown. Here, methods are described to discern the proton-based mechanism using chemical treatments to control the redox state of large perdeuterated MnSOD crystals and subsequent neutron diffraction. These methods could be applicable to other crystal systems in which proton information on the molecule in question in specific chemical states is desired.

Clinical Evaluations of Toxicity and Efficacy of Nanoparticle-Mediated Gene Therapy

Considerable efforts have been devoted to develop safe and efficient gene therapies for life-threatening or inherited diseases. The choice of gene delivery vehicle plays key roles in enhancing the therapeutic effect of nucleic acid cargo. To date, gene therapy approaches involving both viral vectors and nonviral vectors have been evaluated in clinical trials. With improvements in material science and nanotechnologies, positively charged nanoparticles have emerged as potential gene delivery vehicles. In this review, we highlight clinical trials that examined cationic nanocarrier-mediated gene therapy as well as discuss both the toxicity and efficacy of nanocarrier-based therapeutics.

Mechanisms of Normal Tissue Injury From Irradiation

Normal tissue injury from irradiation is an unfortunate consequence of radiotherapy. Technologic improvements have reduced the risk of normal tissue injury; however, toxicity causing treatment breaks or long-term side effects continues to occur in a subset of patients. The molecular events that lead to normal tissue injury are complex and span a variety of biologic processes, including oxidative stress, inflammation, depletion of injured cells, senescence, and elaboration of proinflammatory and profibrogenic cytokines. This article describes selected recent advances in normal tissue radiobiology.

A Review of the Catalytic Mechanism of Human Manganese Superoxide Dismutase

Superoxide dismutases (SODs) are necessary antioxidant enzymes that protect cells from reactive oxygen species (ROS). Decreased levels of SODs or mutations that affect their catalytic activity have serious phenotypic consequences. SODs perform their bio-protective role by converting superoxide into oxygen and hydrogen peroxide by cyclic oxidation and reduction reactions with the active site metal. Mutations of SODs can cause cancer of the lung, colon, and lymphatic system, as well as neurodegenerative diseases such as Parkinson's disease and amyotrophic lateral sclerosis. While SODs have proven to be of significant biological importance since their discovery in 1968, the mechanistic nature of their catalytic function remains elusive. Extensive investigations with a multitude of approaches have tried to unveil the catalytic workings of SODs, but experimental limitations have impeded direct observations of the mechanism. Here, we focus on human MnSOD, the most significant enzyme in protecting against ROS in the human body. Human MnSOD resides in the mitochondrial matrix, the location of up to 90% of cellular ROS generation. We review the current knowledge of the MnSOD enzymatic mechanism and ongoing studies into solving the remaining mysteries.

Genetically modified lentiviruses that preserve microvascular function protect against late radiation damage in normal tissues

Improvements in cancer survival mean that long-term toxicities, which contribute to the morbidity of cancer survivorship, are being increasingly recognized. Late adverse effects (LAEs) in normal tissues after radiotherapy (RT) are characterized by vascular dysfunction and fibrosis causing volume loss and tissue contracture, for example, in the free flaps used for immediate breast reconstruction after mastectomy. We evaluated the efficacy of lentivirally delivered superoxide dismutase 2 (SOD2) overexpression and connective tissue growth factor (CTGF) knockdown by short hairpin RNA in reducing the severity of LAEs in an animal model of free flap LAEs. Vectors were delivered by intra-arterial injection, ex vivo, to target the vascular compartment. LVSOD2 and LVshCTGF monotherapy before irradiation resulted in preservation of flap volume or reduction in skin contracture, respectively. Flaps transduced with combination therapy experienced improvements in both volume loss and skin contracture. Both therapies reduced the fibrotic burden after irradiation. LAEs were associated with impaired vascular perfusion, loss of endothelial permeability, and stromal hypoxia, which were all reversed in the treatment model. Using a tumor recurrence model, we showed that SOD2 overexpression in normal tissues did not compromise the efficacy of RT against tumor cells but appeared to enhance it. LVSOD2 and LVshCTGF combination therapy by targeted, intravascular delivery reduced LAE severities in normal tissues without compromising the efficacy of RT and warrants translational evaluation as a free flap-targeted gene therapy.

Oxidative stress in cancer and fibrosis: Opportunity for therapeutic intervention with antioxidant compounds, enzymes, and nanoparticles

Oxidative stress, mainly contributed by reactive oxygen species (ROS), has been implicated in pathogenesis of several diseases. We review two primary examples; fibrosis and cancer. In fibrosis, ROS promote activation and proliferation of fibroblasts and myofibroblasts, activating TGF-β pathway in an autocrine manner. In cancer, ROS account for its genomic instability, resistance to apoptosis, proliferation, and angiogenesis. Importantly, ROS trigger cancer cell invasion through invadopodia formation as well as extravasation into a distant metastasis site. Use of antioxidant supplements, enzymes, and inhibitors for ROS-generating NADPH oxidases (NOX) is a logical therapeutic intervention for fibrosis and cancer. We review such attempts, progress, and challenges. Lastly, we review how nanoparticles with inherent antioxidant activity can also be a promising therapeutic option, considering their additional feature as a delivery platform for drugs, genes, and imaging agents.

Targeting Liposomal Nanomedicine to Cancer Therapy

Drug delivery systems (DDS) are designed to improve the pharmacological and therapeutic effect. In the past few decades, there are some problems that impeded applications of particulate DDS have been resolved, with several DDS formulations of anticancer now approved for clinical use. Liposomal nanoparticles (LNs) encapsulating therapeutic agents have been recognized as one of the most advanced classes of DDS. Liposomal nanoparticles (LNs) could encapsulate both conventional anticancer drugs and the new genetic drugs with several properties such as high drug-to-lipid ratio, excellent retention of drug and a long circulation lifetime. These excellent properties of LNs have the potentials to offer new treatments in area of cancer therapy. Here, we will discuss recent advances in this field involving conventional anticancer drugs as well as the new genetic drugs.

Radiation-Induced Esophagitis In Vivo and In Vitro Reveals That Epidermal Growth Factor Is a Potential Candidate for Therapeutic Intervention Strategy

PURPOSE

To establish and characterize radiation-induced esophagitis (RIE) in vivo and in vitro.

METHODS AND MATERIALS

Fractionated thoracic irradiation at 0, 8, 12, or 15 Gy was given daily for 5 days to Balb/c or C57Bl/6 mice. Changes in body weight gain and daily food intake were assessed. At the end of the study, we removed the esophagus and examined histology by hematoxylin and eosin staining, immune cell infiltration and apoptosis by fluorescence-activated cell sorting, and gene expression changes by quantitative real-time polymerase chain reaction. Het-1A human esophageal epithelial cells were irradiated at 6 Gy, treated with recombinant human growth factors, and examined for gene expression changes, apoptosis, proliferation, and signal transduction pathways.

RESULTS

We observed that irradiation at 12 Gy or 15 Gy per fraction produced significant reduction in body weight and decreased food intake in Balb/c mice but not as much in C57Bl/6 mice. Further analyses of Balb/c mice irradiated at 12 Gy/fraction revealed attenuated epithelium, inflamed mucosa, and increased numbers of infiltrating CD4+ helper T cells and apoptotic cells. Moreover, we found that expression of tissue inhibitor for metalloproteinase-1, plasminogen activator inhibitor-1, granulocyte macrophage-colony stimulating factor, vascular endothelial growth factor, and stromal-derived factor-1 were increased, whereas epidermal growth factor (EGF) was decreased. Irradiated Het-1A cells similarly showed a significant decrease in expression of EGF and connective tissue growth factor (CTGF). Treatment of EGF but not CTGF partially protected Het-1A cells from radiation-induced apoptosis and revealed phosphorylation of EGFR, AKT, and ERK signaling pathways.

CONCLUSIONS

We established a mouse model of RIE in Balb/c mice with 12 Gy × 5 fractions, which showed reduced body weight gain, food intake, and histopathologic features similar to those of human esophagitis. Decreased EGF expression in the irradiated esophagus suggests that EGF may be a potential therapeutic intervention strategy to treat RIE.

Radioprotectors and Radiomitigators for Improving Radiation Therapy: The Small Business Innovation Research (SBIR) Gateway for Accelerating Clinical Translation

Although radiation therapy is an important cancer treatment modality, patients may experience adverse effects. The use of a radiation-effect modulator may help improve the outcome and health-related quality of life (HRQOL) of patients undergoing radiation therapy either by enhancing tumor cell killing or by protecting normal tissues. Historically, the successful translation of radiation-effect modulators to the clinic has been hindered due to the lack of focused collaboration between academia, pharmaceutical companies and the clinic, along with limited availability of support for such ventures. The U.S. Government has been developing medical countermeasures against accidental and intentional radiation exposures to mitigate the risk and/or severity of acute radiation syndrome (ARS) and the delayed effects of acute radiation exposures (DEARE), and there is now a drug development pipeline established. Some of these medical countermeasures could potentially be repurposed for improving the outcome of radiation therapy and HRQOL of cancer patients. With the objective of developing radiation-effect modulators to improve radiotherapy, the Small Business Innovation Research (SBIR) Development Center at the National Cancer Institute (NCI), supported by the Radiation Research Program (RRP), provided funding to companies from 2011 to 2014 through the SBIR contracts mechanism. Although radiation-effect modulators collectively refer to radioprotectors, radiomitigators and radiosensitizers, the focus of this article is on radioprotection and mitigation of radiation injury. This specific SBIR contract opportunity strengthened existing partnerships and facilitated new collaborations between academia and industry. In this commentary, we assess the impact of this funding opportunity, outline the review process, highlight the organ/site-specific disease needs in the clinic for the development of radiation-effect modulators, provide a general understanding of a framework for gathering preclinical and clinical evidence to obtain regulatory approval and provide a basis for broader venture capital needs and support from pharmaceutical companies to fully capitalize on the advances made thus far in this field.

Antioxidant Approaches to Management of Ionizing Irradiation Injury

Ionizing irradiation induces acute and chronic injury to tissues and organs. Applications of antioxidant therapies for the management of ionizing irradiation injury fall into three categories: (1) radiation counter measures against total or partial body irradiation; (2) normal tissue protection against acute organ specific ionizing irradiation injury; and (3) prevention of chronic/late radiation tissue and organ injury. The development of antioxidant therapies to ameliorate ionizing irradiation injury began with initial studies on gene therapy using Manganese Superoxide Dismutase (MnSOD) transgene approaches and evolved into applications of small molecule radiation protectors and mitigators. The understanding of the multiple steps in ionizing radiation-induced cellular, tissue, and organ injury, as well as total body effects is required to optimize the use of antioxidant therapies, and to sequence such approaches with targeted therapies for the multiple steps in the irradiation damage response.

Esophageal radioprotection by swallowed JP4-039/F15 in thoracic-irradiated mice with transgenic lung tumors

BACKGROUND/AIM

To determine whether Gramicidin S (GS)-nitroxide, JP4-039, esophageal radiation protection protected lung tumors in a transgenic model, LoxP-Stoop-LoxP Kristen Rat Sarcoma Viral oncogene (LSL-K-RAS) mice were administered intra-tracheal- Carbapenem-resistant Enterobacteriaceae (CRE) recombinase, bilateral lung tumors were confirmed at 11 weeks, then thoracic irradiation was delivered.

MATERIALS AND METHODS

Mice received single-fraction 15 Gy or 24 Gy to both lungs, in subgroups receiving intraesophageal administration 10 min before irradiation of JP4-039 (in F15 emulsion) tumor size reduction and survival were investigated. Mice were followed for survival, and reduction in tumor size.

RESULTS

There was no evidence of tumor radioprotection in mice receiving JP4-039/F15.

CONCLUSION

Intraesophageal radioprotective small-molecule antioxidant therapy protects normal tissue but not tumor tissue in mice with transgenic lung tumors.

Manganese superoxide dismutase in cancer prevention

SIGNIFICANCE

Cancer is the second leading cause of death in the United States. Considering the quality of life and treatment cost, the best way to fight against cancer is to prevent or suppress cancer development. Cancer is preventable as indicated by human papilloma virus (HPV) vaccination and tamoxifen/raloxifen treatment in breast cancer prevention. The activities of superoxide dismutases (SODs) are often lowered during early cancer development, making it a rational candidate for cancer prevention.

RECENT ADVANCES

SOD liposome and mimetics have been shown to be effective in cancer prevention animal models. They've also passed safety tests during early phase clinical trials. Dietary supplement-based SOD cancer prevention provides another opportunity for antioxidant-based cancer prevention. New mechanistic studies have revealed that SOD inhibits not only oncogenic activity, but also subsequent metabolic shifts during early tumorigenesis.

CRITICAL ISSUES

Lack of sufficient animal model studies targeting specific cancers; and lack of clinical trials and support from pharmaceutical industries also hamper efforts in further advancing SOD-based cancer prevention.

FUTURE DIRECTIONS

To educate and obtain support from our society that cancer is preventable. To combine SOD-based therapeutics with other cancer preventive agents to obtain synergistic effects. To formulate a dietary supplementation-based antioxidant approach for cancer prevention. Lastly, targeting specific populations who are prone to carcinogens, which can trigger oxidative stress as the mechanism of carcinogenesis.

Can Radiosensitivity Associated with Defects in DNA Repair be Overcome by Mitochondrial-Targeted Antioxidant Radioprotectors

Radiation oncologists have observed variation in normal tissue responses between patients in many instances with no apparent explanation. The association of clinical tissue radiosensitivity with specific genetic repair defects (Wegner's syndrome, Ataxia telangiectasia, Bloom's syndrome, and Fanconi anemia) has been well established, but there are unexplained differences between patients in the general population with respect to the intensity and rapidity of appearance of normal tissue toxicity including radiation dermatitis, oral cavity mucositis, esophagitis, as well as differences in response of normal tissues to standard analgesic or other palliative measures. Strategies for the use of clinical radioprotectors have included modalities designed to either prevent and/or palliate the consequences of radiosensitivity. Most prominently, modification of total dose, fraction size, or total time of treatment delivery has been necessary in many patients, but such modifications may reduce the likelihood of local control and/or radiocurability. As a model system in which to study potential radioprotection by mitochondrial-targeted antioxidant small molecules, we have studied cell lines and tissues from Fanconi anemia (Fancd2(-/-)) mice of two background strains (C57BL/6NHsd and FVB/N). Both were shown to be radiosensitive with respect to clonogenic survival curves of bone marrow stromal cells in culture and severity of oral cavity mucositis during single fraction or fractionated radiotherapy. Oral administration of the antioxidant GS-nitroxide, JP4-039, provided significant radioprotection, and also ameliorated distant bone marrow suppression (abscopal effect of irradiation) in Fancd2 (-/-) mice. These data suggest that radiation protection by targeting the mitochondria may be of therapeutic benefit even in the setting of defects in the DNA repair process for irradiation-induced DNA double strand breaks.

The functional role of MnSOD as a biomarker of human diseases and therapeutic potential of a new isoform of a human recombinant MnSOD

Reactive oxygen species (ROS) are generated as a consequence of metabolic reactions in the mitochondria of eukaryotic cells. This work describes the role of the manganese superoxide dismutase (MnSOD) as a biomarker of different human diseases and proposes a new therapeutic application for the prevention of cancer and its treatment. The paper also describes how a new form of human MnSOD was discovered, its initial application, and its clinical potentials. The MnSOD isolated from a human liposarcoma cell line (LSA) was able to kill cancer cells expressing estrogen receptors, but it did not have cytotoxic effects on normal cells. Together with its oncotoxic activity, the recombinant MnSOD (rMnSOD) exerts a radioprotective effect on normal cells irradiated with X-rays. The rMnSOD is characterized by the presence of a leader peptide, which allows the protein to enter cells: this unique property can be used in the radiodiagnosis of cancer or chemotherapy, conjugating radioactive substances or chemotherapic drugs to the leader peptide of the MnSOD. Compared to traditional chemotherapic agents, the drugs conjugated with the leader peptide of MnSOD can selectively reach and enter cancer cells, thus reducing the side effects of traditional treatments.

Nanomedicine in chemoradiation

Chemoradiotherapy, the concurrent administration of chemotherapy and radiotherapy, is a treatment paradigm in oncology. It is part of the standard of care and curative treatment of many cancers. Given its importance, one of the primary goals of cancer research has been to identify agents and/or strategies that can improve the therapeutic index of chemoradiation. Recent advances in nanomedicine have provided a unique and unprecedented opportunity for improving chemoradiotherapy. Nanoparticles possess properties that are ideally suited for delivering chemotherapy in the chemoradiation setting. The goal of this review is to examine the role of incorporating nanomedicine into chemoradiation and the potential impact of nanomedicine to chemoradiotherapy.

Hematopoietic stem cell regeneration enhanced by ectopic expression of ROS-detoxifying enzymes in transplant mice

High levels of reactive oxygen species (ROS) can exhaust hematopoietic stem cells (HSCs). Thus, maintaining a low state of redox in HSCs by modulating ROS-detoxifying enzymes may augment the regeneration potential of HSCs. Our results show that basal expression of manganese superoxide dismutase (MnSOD) and catalase were at low levels in long-term and short-term repopulating HSCs, and administration of a MnSOD plasmid and lipofectin complex (MnSOD-PL) conferred radiation protection on irradiated recipient mice. To assess the intrinsic role of elevated MnSOD or catalase in HSCs and hematopoietic progenitor cells, the MnSOD or catalase gene was overexpressed in mouse hematopoietic cells via retroviral transduction. The impact of MnSOD and catalase on hematopoietic progenitor cells was mild, as measured by colony-forming units (CFUs). However, overexpressed catalase had a significant beneficial effect on long-term engraftment of transplanted HSCs, and this effect was further enhanced after an insult of low-dose γ-irradiation in the transplant mice. In contrast, overexpressed MnSOD exhibited an insignificant effect on long-term engraftment of transplanted HSCs, but had a significant beneficial effect after an insult of sublethal irradiation. Taken together, these results demonstrate that HSC function can be enhanced by ectopic expression of ROS-detoxifying enzymes, especially after radiation exposure in vivo.

Oxidative stress in apoptosis and cancer: an update

The oxygen paradox tells us that oxygen is both necessary for aerobic life and toxic to all life forms. Reactive oxygen species (ROS) touch every biological and medical discipline, especially those involving proliferative status, supporting the idea that active oxygen may be increased in tumor cells. In fact, metabolism of oxygen and the resulting toxic byproducts can cause cancer and death. Efforts to counteract the damage caused by ROS are gaining acceptance as a basis for novel therapeutic approaches, and the field of prevention of cancer is experiencing an upsurge of interest in medically useful antioxidants. Apoptosis is an important means of regulating cell numbers in the developing cell system, but it is so important that it must be controlled. Normal cell death in homeostasis of multicellular organisms is mediated through tightly regulated apoptotic pathways that involve oxidative stress regulation. Defective signaling through these pathways can contribute to both unbalance in apoptosis and development of cancer. Finally, in this review, we discuss new knowledge about recent tools that provide powerful antioxidant strategies, and designing methods to deliver to target cells, in the prevention and treatment of cancer.

The diverse and complex roles of radiation on cancer treatment: therapeutic target and genome maintenance

Cancer is a genetic disease, grows exponentially with the development of intrinsic and acquired treatment resistance. Past decade has witnessed a considerable progress towards the treatment and understanding of proposed hallmarks of cancer and together with advances in early detection and various treatment modalities. Radiation therapy is an integral part of cancer treatment armamentarium. In developed countries more than half of all cancer patients receive radiation therapy during their course of illness. Although radiation damages both cancer and normal cells, the goal of radiation therapy is to maximize the radiation dose to abnormal cancer cells while minimizing exposure to normal cells, which is adjacent to cancer cells or in the path of radiation. In recent years, life expectancy increases among cancer patients and this increase is due to the results of early diagnosis, screening efforts, improved treatments and with less late effects mostly secondary cancer development. Therefore, cancer survivorship issues have been gaining prominence in the area of radiation oncology research. Understanding the tradeoff between the expected decreases in normal tissue toxicity resulting from an improved radiation dose distribution to the targeted site is an increasingly pertinent, yet needed attention and research in the area of radiation oncology. In recent years, a number of potential molecular targets that involve either with radiation increased tumor cell killing or protecting normal cells have been identified. For clinical benefits, translating these findings to maximize the toxicity of radiation on tumor cells while safeguarding early or late normal cell toxicities using molecular targeted radioprotectors will be useful in radiation treatment.

Strategies for discovery of small molecule radiation protectors and radiation mitigators

Mitochondrial targeted radiation damage protectors (delivered prior to irradiation) and mitigators (delivered after irradiation, but before the appearance of symptoms associated with radiation syndrome) have been a recent focus in drug discovery for (1) normal tissue radiation protection during fractionated radiotherapy, and (2) radiation terrorism counter measures. Several categories of such molecules have been discovered: nitroxide-linked hybrid molecules, including GS-nitroxide, GS-nitric oxide synthase inhibitors, p53/mdm2/mdm4 inhibitors, and pharmaceutical agents including inhibitors of the phosphoinositide-3-kinase pathway and the anti-seizure medicine, carbamazepine. Evaluation of potential new radiation dose modifying molecules to protect normal tissue includes: clonogenic radiation survival curves, assays for apoptosis and DNA repair, and irradiation-induced depletion of antioxidant stores. Studies of organ specific radioprotection and in total body irradiation-induced hematopoietic syndrome in the mouse model for protection/mitigation facilitate rational means by which to move candidate small molecule drugs along the drug discovery pipeline into clinical development.

Amelioration of radiation esophagitis by orally administered p53/Mdm2/Mdm4 inhibitor (BEB55) or GS-nitroxide

BACKGROUND/AIM

Esophagitis is a significant toxicity of radiation therapy for lung cancer. In this study, reduction of irradiation esophagitis in mice, by orally administered p53/Mdm2/Mdm4 inhibitor, BEB55, or the GS-nitroxide, JP4-039, was evaluated.

MATERIALS AND METHODS

BEB55 or JP4-039 in F15 (liposomal) formulation was administered intraesophageally to C57BL/6 mice prior to thoracic irradiation of 29 Gy × 1 or 11.5 Gy × 4 thoracic irradiation. Progenitor cells were sorted from excised esophagus, and nitroxide was quantified, by electron paramagnetic resonance (EPR). Mice with Lewis lung carcinoma (3LL) orthotopic lung tumors were treated with BEB55 or JP4-039 prior to 20 Gy to determine if the drugs would protect the tumor cells from radiation.

RESULTS

Intraesophageal BEB55 and JP4-039 compared to formulation alone increased survival after single fraction (p=0.0209 and 0.0384, respectively) and four fraction thoracic irradiation (p=0.0241 and 0.0388, respectively). JP4-039 was detected in esophagus, liver, bone marrow, and orthotopic Lewis lung carcinoma (3LL) tumor. There was no significant radiation protection of lung tumors by BEB55 or JP4-039 compared to formulation only as assessed by survival (p=0.3021 and 0.3693, respectively). Thus, BEB55 and JP4-039 safely ameliorate radiation esophagitis in mice.

Role of the esophageal vagus neural pathway in ionizing irradiation-induced seizures in nitric oxide synthase-1 homologous recombinant negative NOS1-/- mice

AIM

We sought to define the mechanism of total body irradiation (TBI)-induced seizures in NOS1(-/-) mice and amelioration by intra-esophageal manganese superoxide dismutase-plasmid liposomes (MnSOD-PL).

MATERIALS AND METHODS

We evaluated the role of vagus nerve pathways in irradiation-induced seizures using biochemical, physiologic, and histopathologic techniques.

RESULTS

Heterozygous NOS1(+/-) mice demonstrated radioresistance similar to wild-type C57BL/6NHsd mice (p=0.9269). Irradiation-induced lipid peroxidation in fetal brain cultures from NOS1(-/-) or wild-type mice was reduced by MnSOD-PL. Right-sided vagotomy did not alter the TBI radiation response of wild-type or reverse the radiosensitivity of NOS1(-/-) mice. Excised esophagus from irradiated NOS1(-/-) mice demonstrated an increased histopathologic inflammatory response compared to C57BL/6NHsd mice.

CONCLUSION

NOS1(-/-) mice represent a model system for dissecting the developmental abnormalities leading to esophageal-mediated TBI-induced seizures.

Oxidative Stress Induced by MnSOD-p53 Interaction: Pro- or Anti-Tumorigenic?

The formation of reactive oxygen species (ROS) is a result of incomplete reduction of molecular oxygen during cellular metabolism. Although ROS has been shown to act as signaling molecules, it is known that these reactive molecules can act as prooxidants causing damage to DNA, proteins, and lipids, which over time can lead to disease propagation and ultimately cell death. Thus, restoring the protective antioxidant capacity of the cell has become an important target in therapeutic intervention. In addition, a clearer understanding of the disease stage and molecular events that contribute to ROS generation during tumor promotion can lead to novel approaches to enhance target specificity in cancer progression. This paper will focus on not only the traditional routes of ROS generation, but also on new mechanisms via the tumor suppressor p53 and the interaction between p53 and MnSOD, the primary antioxidant enzyme in mitochondria. In addition, the potential consequences of the p53-MnSOD interaction have also been discussed. Lastly, we have highlighted clinical implications of targeting the p53-MnSOD interaction and discussed recent therapeutic mechanisms utilized to modulate both p53 and MnSOD as a method of tumor suppression.

GS-nitroxide (JP4-039)-mediated radioprotection of human Fanconi anemia cell lines

Fanconi anemia (FA) is an inherited disorder characterized by defective DNA repair and cellular sensitivity to DNA crosslinking agents. Clinically, FA is associated with high risk for marrow failure, leukemia and head and neck squamous cell carcinoma (HNSCC). Radiosensitivity in FA patients compromises the use of total-body irradiation for hematopoietic stem cell transplantation and radiation therapy for HNSCC. A radioprotector for the surrounding tissue would therefore be very valuable during radiotherapy for HNSCC. Clonogenic radiation survival curves were determined for pre- or postirradiation treatment with the parent nitroxide Tempol or JP4-039 in cells of four FA patient-derived cell lines and two transgene-corrected subclonal lines. FancG(-/-) (PD326) and FancD2(-/-) (PD20F) patient lines were more sensitive to the DNA crosslinking agent mitomycin C (MMC) than their transgene-restored subclonal cell lines (both P < 0.0001). FancD2(-/-) cells were more radiosensitive than the transgene restored subclonal cell line (ñ = 2.0 ± 0.7 and 4.7 ± 2.2, respectively, P = 0.03). In contrast, FancG(-/-) cells were radioresistant relative to the transgene-restored subclonal cell line (ñ = 9.4 ± 1.5 and 2.2 ± 05, respectively, P = 0.001). DNA strand breaks measured by the comet assay correlated with radiosensitivity. Cell lines from a Fanc-C and Fanc-A patients showed radiosensitivity similar to that of Fanc-D2(-/-) cells. A fluorophore-tagged JP4-039 (BODIPY-FL) analog targeted the mitochondria of the cell lines. Preirradiation or postirradiation treatment with JP4-039 at a lower concentration than Tempol significantly increased the radioresistance and stabilized the antioxidant stores of all cell lines. Tempol increased the toxicity of MMC in FancD2(-/-) cells. These data provide support for the potential clinical use of JP4-039 for normal tissue radioprotection during chemoradiotherapy in FA patients.

Modulation of in utero total body irradiation induced newborn mouse growth retardation by maternal manganese superoxide dismutase-plasmid liposome (MnSOD-PL) gene therapy

To determine the effects of manganese superoxide dismutase (MnSOD) plasmid liposome (PL) maternal radioprotection on fetal mice, timed pregnant female mice (E14 gestation) were irradiated to 3.0 Gy total body irradiation (TBI) dose, and the number, weight and growth and development over 6 months after birth of newborn mice was quantitated compared with irradiated controls. Maternal MnSOD-PL treatment at E13 improved pup survival at birth (5.4±0.9 per litter) compared with non-irradiated 3.0 Gy controls 4.9±1.1. There was no statistically significant difference in newborn abnormalities, male to female ratio in newborn litters, or other evidence of teratogenesis in surviving newborn mice from MnSOD-PL treated compared with irradiated controls. However, E14 3 Gy irradiated pups from gene therapy-treated mothers showed a significant increase in both growth and overall survival over 6 months after birth (P=0.0022). To determine if transgene product crossed the placenta pregnant E13 mice were injected intravenously with hemagglutinin-epitope-tagged MnSOD (100 μg plasmid in 100 μl liposomes), then after 24 h, fetal mice, placentas and maternal tissues were removed and tested by both immunohistochemistry and reverse transcriptase-PCR for transgene and product. There was no evidence of transgene or product in placenta or any fetal tissue while maternal liver was positive by both assays. The data provide evidence for fetal radioprotection by maternal MnSOD-PL gene therapy before irradiation, which is mediated by an indirect bystander effect and is associated with a significant improvement in both survival at birth and growth and development of newborn mice.

Intraesophageal administration of GS-nitroxide (JP4-039) protects against ionizing irradiation-induced esophagitis

BACKGROUND/AIM

this study evaluated esophageal radioprotection by the Gramicidin S (GS) derived-nitroxide, JP4-039, a mitochondrial targeting peptide-isostere covalently-linked to 4-amino-Tempo, delivered in a novel swallowed oil-based (F15) formulation.

MATERIALS AND METHODS

C57BL/6HNsd female mice received intraesophageal F15 formulation containing JP4-039 (4 mg/ml in 100 microl volumes) 10 minutes before 28 or 29 Gy upper body irradiation compared to MnSOD-PL (100 microl containing 100 microg plasmid) 24 hours prior to irradiation. Subgroups received 1 × 10(7) C57BL/6HNsd, GFP(+) male bone marrow cells intravenously 5 days after irradiation.

RESULTS

JP4-039/F15 or MnSOD-PL increased survival compared to irradiated controls (p<0.0001 for either). Marrow injection further increased survival (p=0.0462 and 0.0351, respectively). Esophagi removed at 1, 3, 7, 14, 24, or 60 days showed bone marrow-derived cells in the esophagi.

CONCLUSION

intraesophageal GS-nitroxide radioprotection is mediated primarily through recovery of endogenous esophageal progenitor cells.