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Although glutathione plays a key role in cancer cell viability and therapy response there is no clear trend in relating the level of this antioxidant to clinical stage, histological grade, or therapy response in patient tumors. The likely reason is that static levels of glutathione are not a good indicator of how a tissue deals with oxidative stress. A better indicator is the functional capacity of the tissue to maintain glutathione levels in response to this stress. However, there are few methods to assess glutathione metabolic function in tissue. We have developed a novel functional mass spectrometry imaging (fMSI) method that can map the variations in the conversion of glycine to glutathione metabolic activity across tumor tissue sections by tracking the fate of three glycine isotopologues administered in a timed sequence to tumor-bearing anesthetized mice. This fMSI method generates multiple time point kinetic data for substrate uptake and glutathione production from each spatial location in the tissue. As expected, the fMSI data shows glutathione metabolic activity varies across the murine 4T1 mammary tumor. Although glutathione levels are highest at the tumor periphery there are regions of high content but low metabolic activity. The timed infusion method also detects variations in delivery of the glycine isotopologues thereby providing a measure of tissue perfusion, including evidence of intermittent perfusion, that contributes to the observed differences in metabolic activity. We believe this new approach will be an asset to linking molecular content to tissue function.

The development of normal lung tissue toxicity after radiation exposure results from multiple changes in cell signaling and communication initiated at the time of the ionizing event. The onset of gross pulmonary injury is preceded by tissue hypoxia and chronic oxidative stress. We have previously shown that development of debilitating lung injury can be mitigated or prevented by administration of AEOL10150, a potent catalytic antioxidant, 24 h after radiation. This suggests that hypoxia-mediated signaling pathways may play a role in late radiation injury, but the exact mechanism remains unclear. The purpose of this study was to evaluate changes in the temporal expression of hypoxia-associated genes in irradiated mouse lung and determine whether AEOL10150 alters expression of these genes. A focused oligo array was used to establish a hypoxia-associated gene expression signature for lung tissue from sham-irradiated or irradiated mice treated with or without AEOL10150. Results were further verified by RT-PCR. Forty-four genes associated with metabolism, cell growth, apoptosis, inflammation, oxidative stress, and extracellular matrix synthesis were upregulated after radiation. Elevated expression of 31 of these genes was attenuated in animals treated with AEOL10150, suggesting that expression of a number of hypoxia-associated genes is regulated by early development of oxidative stress after radiation. Genes identified herein could provide insight into the role of hypoxic signaling in radiation lung injury, suggesting novel therapeutic targets, as well as clues to the mechanism by which AEOL10150 confers pulmonary radioprotection.

Hypoxia-inducible factor 1 (HIF-1) is a master transcriptional factor. Under normal oxygen tension, HIF-1 activity is usually suppressed due to the rapid, oxygen-dependent degradation of one of its two subunits, HIF-1 alpha. Here we report that normoxic HIF-1 activity can be upregulated through NO-mediated S-nitrosylation and stabilization of HIF-1 alpha. In murine tumors, exposure to ionizing radiation stimulated the generation of NO in tumor-associated macrophages. As a result, the HIF-1 alpha protein is S-nitrosylated at Cys533 (through "biotin switch" assay) in the oxygen-dependent degradation domain, which prevents its destruction. Importantly, this mechanism appears to be independent of the prolylhydroxylase-based pathway that is involved in oxygen-dependent regulation of HIF-1 alpha. Selective disruption of this S-nitrosylation significantly attenuated both radiation-induced and macrophage-induced activation of HIF-1 alpha. This interaction between NO and HIF-1 sheds new light on their involvement in tumor response to treatment as well as mammalian inflammation process in general.

Purpose The aim of this study was to determine whether a neutralizing transforming growth factor-{beta} (TGF{beta}) antibody can prevent radiation (RT) induced lung injury. Methods and Materials Fractionated and sham right lung irradiation in Fischer 344 rats was delivered to assess the radioprotective effect of the antibodies. Animals were divided into the following groups: (1) control (sham RT, control antibody 13C4); (2) RT (800cGy x 5)+13C4); (3) RT + 0.1 mg/kg 1D11 anti-TGF{beta} antibody; and (4) RT + 1 mg/kg 1D11 antibody. Antibodies were intraperitoneally administered immediately after the last fraction of RT. Animals were sacrificed at 6 and 26 weeks after irradiation. Lungs were assessed for histologic changes, activation of macrophages, expression/activation of TGF{beta} and its signal transduction pathway. Results At 6 weeks post-RT, there was a significant reduction in macrophage accumulation (p = 0.041), alveolar wall thickness (p = 0.0003), and TGF-{beta} activation (p = 0.032) in animals receiving 1.0 mg/kg 1D11 vs. in the control group. However, at 6 weeks, the low dose of 1D11 antibody (0.1 mg/kg) failed to produce any significant changes. At 6 months post-RT, radioprotection is apparent for the group receiving 1.0 mg/kg 1D11, with activated macrophages (p = 0.037), alveolar wall thicknessmore » (p = 0.0002), TGF{beta} activation (p = 0.002) and its signal transduction proteins (p < 0.05) compared with the control group. Conclusions Administration of a single dose of 1.0 mg/kg of the anti-TGF{beta} antibody 1D11 resulted in decreased morphologic changes, inflammatory response, and reduced expression and activation of TGF{beta} 6 weeks and 6 months after 40 Gy to the right hemithorax. Targeting the TGF{beta} pathway may be a useful strategy to prevent radiation-induced lung injury.« less

Purpose: To analyze plasma cytokine profiles before the initiation of radiation therapy to define a cytokine phenotype that correlates with risk of developing symptomatic radiation-induced lung injury (SRILI). Methods and Materials: Symptomatic radiation-induced lung injury was evaluated in 55 patients (22 with SRILI and 33 without SRILI), according to modified National Cancer Institute common toxicity criteria. These plasma samples were analyzed by the multiplex suspension bead array system (Bio-Rad Laboratories; Hercules, CA), which included the following cytokines: interleukin (IL)-1β, IL-2, IL-4, IL-5, IL-6, IL-7, IL-8, IL-10, IL-12p70, IL-13, IL-17, granulocyte/macrophage colony-stimulating factor, interferon-γ, monocyte chemotactic protein 1, macrophage inflammatory protein 1β, tumor necrosis factor α, and granulocyte colony-stimulating factor. Results: Significant differences in the median values of IL-8 were observed between patients with and without SRILI. Patients who did not develop SRILI had approximately fourfold elevated levels of IL-8 as compared with patients who did subsequently develop SRILI. Significant correlations were not found for any other cytokine in this study, including transforming growth factor β1. Conclusions: Patients with lower levels of plasma IL-8 before radiation therapy might be at increased risk for developing SRILI. Further studies are necessary to determine whether IL-8 levels are predictive of SRILI in a prospective trial and whether this marker might be used to determine patient eligibility for dose escalation.

The ability to optimize treatments for cancer on the basis of relative risks for normal tissue injury has important implications in oncology, because higher doses of radiation might, in some diseases, improve both local control and survival. To achieve this goal, a thorough understanding of the molecular mechanisms responsible for radiation-induced toxicity will be essential. Recent research has demonstrated that ionizing radiation triggers a series of genetic and molecular events, which might lead to chronic persistent alterations in the microenvironment and an aberrant wound-healing response. Disrupted epithelial-stromal cell communication might also be important. With the application of a better understanding of fundamental biology to clinical practice, new approaches to treating and preventing normal tissue injury can focus on correcting these disturbed molecular processes.

Radiation-induced lung toxicity is a significant dose-limiting side effect of radiotherapy for thoracic tumors. Recombinant human keratinocyte growth factor (rHuKGF) has been shown to be a mitogen for type II pneumocytes. The purpose of this study was to determine whether rHuKGF prevents or ameliorates the severity of late lung damage from fractionated irradiation in a rat model.Female Fisher 344 rats were irradiated to the right hemithorax with a dose of 40 Gy/5 fractions/5 days. rHuKGF at dose of 5 mg/kg or 15 mg/kg was given via a single intravenous injection 10 min after the last fraction of irradiation. Animals were followed for 6 months after irradiation.The breathing rate increased beginning at 6 weeks and reached a peak at 14 weeks after irradiation. The average breathing frequencies in the irradiated groups with rHuKGF (5 mg/kg and 15 mg/kg) treatment were significantly lower than that in the group receiving radiation without rHuKGF (116.5 +/- 1.0 and 115.2 +/- 0.8 vs 123.5 +/- 1.2 breaths/min, p0.01). The severity of lung fibrosis and the level of immunoreactivity of integrin alphavbeta6, TGFbeta1, type II TGFbeta receptor, Smad3, and phosphorylated Smad2/3 were significantly decreased only in the group receiving irradiation plus high-dose rHuKGF treatment compared with irradiation plus vehicle group, suggesting a dose response for the effect of rHuKGF.This study is the first to demonstrate that rHuKGF treatment immediately after irradiation protects against late radiation-induced pulmonary toxicity. These results suggest that restoration of the integrity of the pulmonary epithelium via rHuKGF stimulation may downregulate the TGF-beta-mediated fibrosis pathway. These data also support the use of rHuKGF in a clinical trial designed to prevent radiation-induced lung injury.

Purpose The purpose of this study was to determine if radiation-induced lung injury is associated with prolonged oxidative stress, and whether chronic overexpression of extracellular superoxide dismutase (EC-SOD) in the lung of transgenic mice protects against radiation-induced lung injury. Methods and materials Whole-lung radiation was delivered to EC-SOD overexpressing B6C3 transgenic (XRT-TG) mice and wild-type littermates (XRT-WT). Pulmonary function was assessed by breathing frequency. Right lung wet weight was used as a gross indicator of lung damage. Histopathology was used to assess collagen deposition and tissue fibrosis according to an established grading system. Immunohistochemistry was used to stain and quantify the number of macrophages. ELISA was used to measure activated TGF-β1. Oxidative stress was assessed by measuring lipid oxidation products (malondialic acid) by HPLC. Results Four of six XRT-WT mice required euthanasia at 15–19 weeks postradiation because of respiratory distress, whereas no XRT-TG mouse developed distress. All assessments of lung damage at 15–20 weeks postradiation were higher for XRT-WT mice compared with the XRT-TG mice, including breathing frequency (380 vs. 286 bpm, p ≤ 0.0004), right lung weight (228 vs. 113 mg, p ≤ 0.06), macrophage count (48 vs. 5 per 40× field, p ≤ 0.06), and percent activated TGF-β1 (37 vs. 11%, p ≤ 0.06). Semiquantitative measures, including fibrosis and collagen deposition, were also higher for XRT-WT mice, with an exact Fisher p value of ≤0.03 for both variables. In addition, malondialic acid was elevated in XRT-WT mice 15–20 weeks after radiation delivery, and levels were lower in the XRT-TG mice (624 vs. 323 pmol/mg protein, p ≤ 0.06). Conclusions After radiation therapy, oxidative stress is present at 15–20 weeks after initial exposure, which correlates with the delayed clinical onset of radiation-induced lung damage. Overexpression of EC-SOD in transgenic mice appears to confer protection against this radiation-induced lung injury, with a corresponding decrease in oxidative stress. EC-SOD may be a potential therapeutic agent for radioprotection in the treatment of thoracic malignancies. Further investigation is needed to confirm and expand on the current results.

Purpose To assess whether administration of recombinant human adenoviral vector, which carries soluble TGFβ1 Type II receptor (TβRII) gene, might reduce the availability of active TGFβ1 and thereby protect the lung from radiation-induced injury. Methods and materials Female Fisher 344 rats were given a single 30 Gy dose of right hemithoracic irradiation 24 h after the injections of control (AdGFP) or treatment (AdexTβRII-Fc) vectors. Different end points were assessed to look for lung tissue damage. Results There was a significant increase in the plasma level of soluble TβRII 24 h and 48 h after injection of treatment vector. In the radiation (RT) + AdexTβRII-Fc group, there was a significant reduction in respiratory rate at 4 weeks after treatment as compared to the RT-alone group. Histologic results revealed a significant reduction in lung damage and decrease in the number and activity of macrophages in the RT + AdexTβRII-Fc group as compared to the RT-alone group. The tissue level of active TGFβ1 was significantly reduced in rats receiving RT + AdexTβRII-Fc treatment. There was also an upregulation of transmembrane TβRII in lung tissue in the RT-alone group as compared to the RT + gene therapy rats. Conclusions This study shows the ability of AdexTβRII-Fc gene therapy to induce an increase in circulating levels of soluble receptors, to reduce the tissue level of active TGFβ1, and consequently to ameliorate acute radiation-induced lung injury.

Radiation therapy (RT) is an important therapeutic modality in the treatment of thoracic tumors. The maximum doses to these tumors are often limited by the radiation tolerance of lung tissues. Lung injury from ionizing radiation is believed to be a consequence of oxidative stress and a cascade of cytokine activity. Superoxide dismutase (SOD) is a key enzyme in cellular defenses against oxidative damage. The objective of this study was to determine whether the SOD mimetic AEOL 10113 [manganese (III) mesotetrakis (N-ethylpyridinium-2-yl) porphyrin (MnTE-2-PyP(5+))] increases the tolerance of lung to ionizing radiation. AEOL 10113 was able to significantly reduce the severity of RT-induced lung injury. This was strongly supported with histopathology results and measurements of collagen deposition (hydroxyproline content). There was a significant reduction in the plasma level of the profibrogenic cytokine transforming growth factor-beta (TGF-beta) in the group of rats receiving RT + AEOL 10113. In conclusion, the novel SOD mimetic, AEOL 10113, demonstrates a significant protective effect from radiation-induced lung injury.

Purpose: The purpose of this study was to determine whether or not hypoxia develops in rat lung tissue after radiation. Methods and Materials: Fisher-344 rats were irradiated to the right hemithorax using a single dose of 28 Gy. Pulmonary function was assessed by measuring the changes in respiratory rate every 2 weeks, for 6 months after irradiation. The hypoxia marker was administered 3 h before euthanasia. The tissues were harvested at 6 weeks and 6 months after irradiation and processed for immunohistochemistry. Results: A moderate hypoxia was detected in the rat lungs at 6 weeks after irradiation, before the onset of functional or histopathologic changes. The more severe hypoxia, that developed at the later time points (6 months) after irradiation, was associated with a significant increase in macrophage activity, collagen deposition, lung fibrosis, and elevation in the respiratory rate. Immunohistochemistry studies revealed an increase in TGF-β, VEGF, and CD-31 endothelial cell marker, suggesting a hypoxia-mediated activation of the profibrinogenic and proangiogenic pathways. Conclusion: A new paradigm of radiation-induced lung injury should consider postradiation hypoxia to be an important contributing factor mediating a continuous production of a number of inflammatory and fibrogenic cytokines.

(RT/CT) underwent serial MRI before (1st MRI) and during RT at 2–2.5 weeks (2nd MRI, at 20–25 Gy), at 4–5 weeks of RT (3rd MRI, at 45–50 Gy), and 1–2 months post-RT. Mean follow up was 6.2 (0.2–9.4) years. Tumor volume was measured by MRI 3D volumetry, and plotted as time/tumor volume regression curves. The volume regression parameters were correlated with local tumor control and disease-free survival.

(37 C, 5% CO2) for 7 days before being assayed for survival using a standard clonogenic assay. Results: Data indicated that both miso and 10mM genistein treatments resulted in a reduction in PC3 cell colony number of w20%, suggesting a marked growth inhibitory action for these compounds. Treatment with 30mM genistein enhanced PC3 cell growth inhibition even more substantially, resulting in an 85% reduction in cell colony number compared to untreated controls. Additionally, data from these studies suggested that both miso and genistein continued to exert their growth inhibitory effect on the PC3 cells over a range of radiation exposures up to 300cGy. However, a differential response was seen between the misotreated and 10mM genistein-treated radiation cell survival curves and the 30mM genistein-treated radiation cell survival curve. Specifically, both the miso and 10mM genistein treatments interacted with radiation treatments in an additive manner, resulting in enhanced tumor cell kill, but producing radiation cell survival curves whose shape was almost identical to the untreated irradiated control. In contrast, the reduction in colony number in PC3 cells treated with 30mM genistein plus radiation resulted in a highly supra-additive reduction in colony number, especially at doses greater than 50cGy, thereby, producing a markedly steeper radiation cell survival curve than observed for the untreated irradiated control. Conclusions: Data suggest that administration of either miso or genistein may potentiate radiation-induced prostate tumor cell kill. This is particularly true when combining higher doses of genistein (30mM) with radiation, where synergistic cell kill appears to occur. These results may have consequence as a way to improve the outcome of radiation therapy regimens for prostate cancer patients. Author Disclosure: J. Sattler: None. C.R. Kempf: None. R.M. Johnke: None.

Vujaskovic, Z., Feng, Q. F., Rabbani, Z. N., Anscher, M. S., Samulski, T. V. and Brizel, D. M. Radioprotection of Lungs by Amifostine is Associated with Reduction in Profibrogenic Cytokine Activity. Radiat. Res. 157, 656–660 (2002). Radiation-induced pulmonary toxicity causes significant morbidity and mortality in patients irradiated for lung cancer, breast cancer, lymphoma or thymoma. Amifostine is an important drug in the emerging field of cytoprotection. Recent advances in our understanding of the mechanism of radiation-induced injury at the molecular and cellular levels have stimulated interest in the development of effective radioprotective strategies. Accumulation of macrophages with associated production of reactive oxygen species (ROS) and production and activation of cytokines is a key process involved in the pathophysiology of radiation injury in the lung. The purpose of this study was to determine whether the mechanism of radioprotection by amifostine includes reduction in both macroph...

Objectives Calcitriol has been reported to have antitumor efficacy in several cancers. In this study, we hypothesized that calcitriol may potentially function as a cryosensitizer that can enhance cryoablation, and we investigated several molecular marker changes in a murine model of prostate cancer. Methods Murine prostate tumors (RM-9) were grown in male C57BL/6J mice subcutaneously with neoadjuvant intratumoral injection of calcitriol followed by cryoablation. The microenvironmental changes after cryoablation alone and in combination with calcitriol were analyzed in a comparative fashion using immunohistochemistry and Western blot analyses. Results Both cryoablation and the combination group could suppress tumor growth after treatment compared with the control. At final pathologic assessment, a larger necrotic area was seen in the combination group ( P = .026). Although microvessel density (CD31) and the area of hypoxia (pimonidazole) was not different between the control and combination groups, cell proliferation (Ki-67) significantly decreased in the combination treatment ( P = .035). In Western blot analyses, several markers for apoptosis were expressed significantly higher with the combination treatment. Conclusions The synergistic effect of calcitriol with cryoablation was demonstrated because of enhanced antitumor efficacy by increasing necrosis and apoptosis and reduced cell proliferation. This study suggests that calcitriol is a potentially applicable reagent as a freeze sensitizer to cryoablation.

Purpose/Objective: The cytokine Transforming Growth Factor (TGF ) has been shown to play an important role in fibrogenesis associated with radiation (RT) induced normal tissue injury. Antagonists of TGF may have great potential to reduce formation of fibrous tissue and thereby protect normal tissues from the adverse effects of radiation. The purpose of this study is to determine whether an anti-TGF antibody (1D11, Genzyme Corp, Cambridge, MA) can prevent/ameliorate radiation induced lung injury.

Purpose/Objective: Radiation induced lung injury is mediated by reactive oxygen species. Superoxide dismutase is involved in the processing of these free radicals. Overexpression of extracellular superoxide dismutase (EC-SOD) has been shown to protect against radiation induced lung injury. The purpose of this study is to evaluate if the transforming growth factor beta (TGF )/smad3 signal transduction pathway is involved in the pathogenesis of radiation induced lung toxicity.