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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.

Supplementary Figure 1 from Tumor Necrosis Factor-α Is a Potent Endogenous Mutagen that Promotes Cellular Transformation

Tumor necrosis factor-α (TNF-α) is an important inflammation cytokine without known direct effect on DNA. In this study, we found that TNF-α can cause DNA damages through reactive oxygen species. The mutagenic effect of TNF-α is comparable with that of ionizing radiation. TNF-α treatment in cultured cells resulted in increased gene mutations, gene amplification, micronuclei formation, and chromosomal instability. Antioxidants significantly reduced TNF-α–induced genetic damage. TNF-α also induced oxidative stress and nucleotide damages in mouse tissues in vivo. Moreover, TNF-α treatment alone led to increased malignant transformation of mouse embryo fibroblasts, which could be partially suppressed by antioxidants. As TNF-α is involved in chronic inflammatory diseases, such as chronic hepatitis, ulcerative colitis, and chronic skin ulcers, and these diseases predispose the patients to cancer development, our results suggest a novel pathway through which TNF-α promotes cancer development through induction of gene mutations, in addition to the previously reported mechanisms, in which nuclear factor-κB activation was implicated. (Cancer Res 2006; 66(24): 11565-70)

Supplementary Materials and Figure Legend from Tumor Necrosis Factor-α Is a Potent Endogenous Mutagen that Promotes Cellular Transformation

Resistance of hypoxic solid tumor niches to chemotherapy and radiotherapy remains a major scientific challenge that calls for conceptually new approaches. Here we exploit a hitherto unrecognized ability of sickled erythrocytes (SSRBCs) but not normal RBCs (NLRBCs) to selectively target hypoxic tumor vascular microenviroment and induce diffuse vaso-occlusion. Within minutes after injection SSRBCs, but not NLRBCs, home and adhere to hypoxic 4T1 tumor vasculature with hemoglobin saturation levels at or below 10% that are distributed over 70% of the tumor space. The bound SSRBCs thereupon form microaggregates that obstruct/occlude up to 88% of tumor microvessels. Importantly, SSRBCs, but not normal RBCs, combined with exogenous prooxidant zinc protoporphyrin (ZnPP) induce a potent tumoricidal response via a mutual potentiating mechanism. In a clonogenic tumor cell survival assay, SSRBC surrogate hemin, along with H(2)O(2) and ZnPP demonstrate a similar mutual potentiation and tumoricidal effect. In contrast to existing treatments directed only to the hypoxic tumor cell, the present approach targets the hypoxic tumor vascular environment and induces injury to both tumor microvessels and tumor cells using intrinsic SSRBC-derived oxidants and locally generated ROS. Thus, the SSRBC appears to be a potent new tool for treatment of hypoxic solid tumors, which are notable for their resistance to existing cancer treatments.

Detecting the effects of low oxygen on cell function is often dependent on monitoring the expression of a number of hypoxia markers. The time dependence of the appearance and stability of these markers varies between cell lines. Assessing cellular marker dynamics is also critical to determining how quickly cells respond to transient changes in oxygen levels that occurs with cycling hypoxia. We fabricated a manifold designed to use flow-encoding to produce sequential changes in gas mixtures delivered to a permeable-bottom 96-well plate. We show how this manifold and plate design can be used to expose cells to either static or cycling hypoxic conditions for eight different time periods thereby facilitating the study of the time-response of cells to altered oxygen environments. Using this device, we monitored the time-dependence of molecular changes in human PANC-1 pancreatic carcinoma and Caco-2 colon adenocarcinoma cells exposed to increasing periods of static or cycling hypoxia. Using immunohistochemistry, both cell lines show detectable levels of the marker protein hypoxia-inducible factor-1α (HIF-1α) after 3 h of exposure to static hypoxia. Cycling hypoxia increased the expression level of HIF-1α compared to static hypoxia. Both static and cycling hypoxia also increased glucose uptake and aldehyde dehydrogenase activity. This new device offers a facile screening approach to determine the kinetics of cellular alterations under varying oxygen conditions.

Precise oxygen control is critical to evaluating cell growth, molecular content, and stress response in cultured cells. We have designed, fabricated, and characterized a 96-well plate-based device that is capable of delivering eight static or dynamically changing oxygen environments to different rows on a single plate. The device incorporates a gas-mixing tree that combines two input gases to generate the eight gas mixtures that supply each row of the plate with a different gas atmosphere via a removable manifold. Using air and nitrogen as feed gases, a single 96-well plate can culture cells in applied gas atmospheres with Po2 levels ranging from 1 to 135 mmHg. Human cancer cell lines MCF-7, PANC-1, and Caco-2 were grown on a single plate under this range of oxygen levels. Only cells grown in wells exposed to Po2 ≤37 mmHg express the endogenous hypoxia markers hypoxia-inducible factor-1α and carbonic anhydrase IX. This design is amenable to multiwell plate-based molecular assays or drug dose-response studies in static or cycling hypoxia conditions.

The objective of the present study was to determine whether single administration of the antioxidant enzyme bovine superoxide dismutase (bSOD) after radiation therapy (RT) mitigates development of pulmonary toxicity in rats.Female F344 rats (n = 60) were divided among six experimental groups: (1) RT, single dose of 21 Gy to the right hemithorax; (2) RT + 5 mg/kg bSOD; (3) RT + 15 mg/kg bSOD; (4) No RT; (5) sham RT + 5 mg/kg bSOD; and (6) sham RT + 15 mg/kg bSOD. A single subcutaneous injection of bSOD (5 or 15 mg/kg) was administered 24 h post-radiation. The effects of bSOD on radiation-induced lung injury were assessed by measurement of body weight, breathing frequency, and histopathological changes. Immunohistochemistry was used to evaluate oxidative stress (8-OHdG(+), NOX4(+), nitrotyrosine(+), and 4HNE(+) cells), macrophage activation (ED1(+)), and expression of profibrotic transforming growth factor-β or TGF-β in irradiated tissue.Radiation led to an increase in all the evaluated parameters. Treatment with 15 mg/kg bSOD significantly decreased levels of all the evaluated parameters including tissue damage and breathing frequency starting 6 weeks post-radiation. Animals treated with 5 mg/kg bSOD trended toward a suppression of radiation-induced lung damage but did not reach statistical significance.The single application of bSOD (15 mg/kg) ameliorates radiation-induced lung injury through suppression of reactive oxygen species/reactive nitrogen species or ROS/RNS-dependent tissue damage.

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.

Introduction The mechanisms of radiation‐induced erectile dysfunction (ED) are unclear, as clinical studies are limited, and previous animal models were based on wide‐field irradiation, which does not model current radiotherapy (RT) techniques. Aims To perform functional and morphological analyses of erectile function (EF) utilizing image‐guided stereotactic prostate‐confined RT in a rat model. Methods Sixty young adult male rats aged 10–12 weeks old were divided into age‐matched sham and RT groups. A single 20‐Gy fraction to the prostate was delivered to RT animals. Penile bulb, shaft, and testes were excluded from treatment fields. Main Outcome Measures Bioassay and intracavernous pressure (ICP) measurements were conducted at 2, 4, and 9 weeks following RT. Perfusion analysis of the corpora cavernosa (CC) was conducted using Hoechst injected prior to sacrifice. Penile shaft and cavernous nerve (CN) were evaluated by immunohistochemistry. Plasma testosterone level was analyzed using a testosterone enzyme‐linked immunosorbent assay (ELISA) assay kit. Results Irradiated animals demonstrated statistically significant time‐dependent functional impairment of EF by bioassay and ICP measurement from 4 weeks. Neuronal nitric oxide synthase (NOS) expression was decreased in CN by 4 weeks. In CC, expression levels of anti‐alpha smooth muscle actin and endothelial NOS were significantly decreased at 9 weeks. In penile dorsal vessels, smooth muscle/collagen ratio was significantly decreased at 4 and 9 weeks. Additionally, Hoechst perfusion showed time‐dependent decrease in CC of RT animals, whereas CD31 expression was not affected. No toxicities were noted; testosterone levels were similar in both groups. Conclusion We demonstrated time‐dependent ED following image‐guided stereotactic RT. Our results imply that reduction of neuronal NOS expression in cavernous nerve could trigger consecutive reduction of smooth muscle content as well as blood perfusion in CC that resulted in corporal veno‐occlusive dysfunction. Present study could be a cornerstone to future research that may bring comprehensive scientific understanding of radiation‐induced ED. Kimura M, Yan H, Rabbani Z, Satoh T, Baba S, Yin F‐F, Polascik TJ, Donatucci CF, Vujaskovic Z, and Koontz BF. Radiation‐induced erectile dysfunction using prostate‐confined modern radiotherapy in a rat model. J Sex Med 2011;8:2215–2226.

The metabolism of glycine into glutathione was monitored noninvasively in vivo in intact rat mammary adenocarcinomas (R3230Ac) by MRI and MRS. Metabolism was tracked by following the isotope label from intravenously infused [2-13C]-glycine into the glycinyl residue of glutathione. Signals from [2-13C]-glycine and γ-glutamylcysteinyl-[2-13C]-glycine (13C-glutathione) were detected by nonlocalized 13C spectroscopy, as these resonances are distinct from background signals. In addition, using spectroscopic imaging methods, heterogeneity in the in vivo tumor distribution of glutathione was observed. In vivo spectroscopy also detected isotope incorporation from [2-13C]-glycine into both the 2- and 3-carbons of serine. Analyses of tumor tissue extracts showed single- and multiple-label incorporation from [2-13C]-glycine into serine from metabolism through the serine hydroxymethyltransferase and glycine cleavage system pathways. Mass spectrometric analysis of extracts also showed that isotope-labeled serine is further metabolized via the trans-sulfuration pathway, as 13C isotope labels appear in both the glycinyl and cysteinyl residues of glutathione. Our studies demonstrate the use of MRI and MRS for the monitoring of tumor metabolic processes central to oxidative stress defense. Copyright © 2011 John Wiley & Sons, Ltd.

The aim of this study was to examine the prognostic significance of carbonic anhydrase IX (CA-IX), an endogenous marker for tumor hypoxia; endoglin (CD105), a proliferation-associated and hypoxia-inducible glycoprotein and 8-hydroxy-2'-deoxyguanosine (8-OHdG), an oxidative DNA lesion, in breast cancer patients. Immunohistochemical expressions of CA-IX, CD105 and 8-OHdG, analyzed on paraffin-embedded tumor tissues from forty female breast cancer patients, were used to assess their prognostic implication on overall survival (OS) and relapse-free survival (RFS). Patients with high CA-IX expression (above cut-off value) had a higher occurrence of relapse (P = = 0.002). High CA-IX expression was significantly associated with shorter RFS (P 0.001, hazard ratio (HR) 0.21) and shorter OS (P 0.001, HR 0.19). Lymph node negative patients with high CA-IX expression had worse RFS (P = 0.031, HR 0.14) and OS (P = 0.005, HR 0.05). Patients with grade III tumors and high CA-IX expression showed shorter RFS (P = 0.028, HR 0.28) and OS (P = 0.008, HR 0.20). Worse OS (P = 0.046, HR 0.28) was found in subgroup of patients with grade II tumors and high CA-IX expression. Among all three markers, only high CA-IX expression was strong independent prognostic indicator for shorter OS (HR 4.14, 95% CI 1.28-13.35, P = 0.018) and shorter RFS (HR 3.99, 95% CI 1.38-11.59, P = 0.011). Elevated expression of CA-IX was an independent prognostic factor for decreased RFS and OS and a significant marker for tumor aggressiveness. CD105 had week prognostic value; whereas, 8-OHdG, in this study, did not provide sufficient evidence as a prognostic indicator in breast cancer patients.

Purpose The prognostic significance of epidermal growth factor receptor (EGFR) and cyclooxygenase-2 (COX-2) expression remains unestablished, although EGFR and COX-2 are frequently overexpressed in non-small cell lung cancer (NSCLC). Considering the importance of EGFR activation after ligand binding, however, the expression of phosphorylated EGFR (p-EGFR) may have more significance in predicting tumor aggressiveness in NSCLC than either EGFR or COX-2 expression. Patients and methods We studied the relationships between p-EGFR, EGFR, and COX-2 overexpression and examined their association with prognosis in localized NSCLC. The expression of p-EGFR, EGFR, and COX-2 was studied by immunohistochemistry in 77 surgically-resected stage I/II NSCLC cases. EGFR mutational status was determined by sequencing exons 18–21. Correlation of expression with clinical outcome and other biomarkers, including Ki-67 and microvessel density (MVD), was also examined. Results Out of the 77 patients, EGFR overexpression was observed in 37 (48.1%), p-EGFR expression was found in 22 (28.6%), and COX-2 overexpression was seen in 45 (58.4%). Expression of p-EGFR was associated with COX-2 overexpression (P = 0.047), but not EGFR overexpression or high Ki-67 (P = 0.087 and P = 0.092, respectively). COX-2 overexpression was significantly associated with high Ki-67 (P = 0.011). Expression of p-EGFR correlated with lower disease-free survival (P = 0.045), but not overall survival. Neither EGFR nor COX-2 overexpression was associated with prognosis. Conclusion p-EGFR appears to be a better indicator for lower disease-free survival than EGFR overexpression itself in localized NSCLC. Pathways other than EGFR activation may influence COX-2 overexpression.

Imatinib, an inhibitor of PDGF-Rbeta and other tyrosine kinase receptors, has been shown to decrease microvessel density and interstitial fluid pressure in solid tumours, thereby improving subsequent delivery of small molecules. The purpose of this study was to test whether pretreatment with imatinib increases the efficacy of traditional chemotherapy in mice bearing non-small cell lung carcinoma xenografts, and to investigate the effects of imatinib on liposomal drug delivery. Efficacy treatment groups included (n=9-10): saline control, imatinib alone (oral gavage, 100 mg kg(-1) x 7 days), docetaxel alone (10 mg kg(-1) i.p. 2 x /week until killing), and imatinib plus docetaxel (started on day 7 of imatinib). Tumours were monitored until they reached four times the initial treatment volume (4 x V) or 28 days. A separate experiment compared tumour doxorubicin concentrations (using high performance liquid chromatography) 24 h after treatment with liposomal doxorubicin alone (6 mg kg(-1) i.v., n=9) or imatinib plus liposomal doxorubicin (n=16). Imatinib plus docetaxel resulted in significantly improved antitumour efficacy (0/10 animals reached 4 x V by 28 days) when compared to docetaxel alone (3/9 reached 4 x V, P=0.014) or imatinib alone (9/10 reached 4 x V, P=0.025). Pretreatment with imatinib also significantly increased tumour concentrations of liposomal doxorubicin. Overall, these preclinical studies emphasise the potential of imatinib as an adjunct to small molecule or liposomal chemotherapy.

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.

The objective of this study was to determine whether administration of a catalytic antioxidant, Mn(III) tetrakis(N,N'-diethylimidazolium-2-yl) porphyrin, AEOL10150, reduces the severity of long-term lung injury induced by fractionated radiation (RT). Fisher 344 rats were randomized into five groups: RT+AEOL10150 (2.5 mg/kg BID), AEOL10150 (2.5 mg/kg BID) alone, RT+ AEOL10150 (5 mg/kg BID), AEOL10150 (5 mg/kg BID) alone and RT alone. Animals received five 8 Gy fractions of RT to the right hemithorax. AEOL10150 was administered 15 min before RT and 8 h later during the period of RT treatment (5 days), followed by subcutaneous injections for 30 days, twice daily. Lung histology at 26 weeks revealed a significant decrease in lung structural damage and collagen deposition in RT+AEOL10150 (5 mg/kg BID) group, in comparison to RT alone. Immunohistochemistry studies revealed a significant reduction in tissue hypoxia (HIF1alpha, CAIX), angiogenic response (VEGF, CD-31), inflammation (ED-1), oxidative stress (8-OHdG, 3-nitrotyrosine) and fibrosis pathway (TGFbeta1, Smad3, p-Smad2/3), in animals receiving RT+ AEOL10150 (5 mg/kg BID). Administration of AEOL10150 at 5 mg/kg BID during and after RT results in a significant protective effect from long-term RT-induced lung injury. Low dose (2.5 mg/kg BID) delivery of AEOL10150 has no beneficial radioprotective effects.

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

Aptamers offer advantages over other oligonucleotide-based approaches that artificially interfere with target gene function due to their ability to bind protein products of these genes with high affinity and specificity. However, RNA aptamers are limited in their ability to target intracellular proteins since even nuclease-resistant aptamers do not efficiently enter the intracellular compartments. Moreover, attempts at expressing RNA aptamers within mammalian cells through vector-based approaches have been hampered by the presence of additional flanking sequences in expressed RNA aptamers, which may alter their functional conformation. In this report, we successfully expressed a 'pure' RNA aptamer specific for NF-kappaB p50 protein (A-p50) utilizing an adenoviral vector employing the H1 RNA polymerase III promoter. Binding of the expressed aptamer to its target and subsequent inhibition of NF-kappaB mediated intracellular events were demonstrated in human lung adenocarcinoma cells (A549), murine mammary carcinoma cells (4T1) as well as a human tumor xenograft model. This success highlights the promise of RNA aptamers to effectively target intracellular proteins for in vitro discovery and in vivo applications.

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.

Tumour hypoxia has been shown to increase mutation rate, angiogenesis, and metastatic potential, and decrease response to conventional therapeutics. Improved tumour oxygenation should translate into increased treatment response. Exogenous recombinant erythropoietin (rEpo) has been recently shown to increase tumour oxygenation in a mammary carcinoma model. The mechanism of this action is not yet understood completely. The presence of Epo and its receptor (EpoR) have been demonstrated on several normal and neoplastic tissues, including blood vessels and various solid tumours. In addition, rEpo has been shown in two recent prospective, randomized clinical trials to negatively impact treatment outcome. In this study, we attempt to characterize the direct effects of rEpo on tumour growth and angiogenesis in two separate rodent carcinomas. The effect of rEpo on R3230 rat mammary adenocarcinomas, CT-26 mouse colon carcinomas, HCT-116 human colon carcinomas, and FaDu human head and neck tumours, all of which express EpoR, was examined. There were no differences in tumour growth or proliferation (measured by Ki-67) between placebo-treated and rEpo-treated tumours. In the mammary window chamber, vascular length density (VLD) measurements in serial images of both placebo-treated and Epo-treated rats revealed no difference in angiogenesis between the Epo-treated tumours and placebo-treated tumours at any time point. These experiments are important because they suggest that the recent clinical detriment seen with the use of Epo is not due to its tumour growth effects or angiogenesis. These studies also suggest that further preclinical studies need to examine rEpo's direct tumour effects in efforts to improve the therapeutic benefits of Epo in solid tumour patients.

Cyclophilin A (CypA) was recently reported to be overexpressed in non–small-cell lung cancer, and represents a potentially novel therapeutic target. To determine the role of CypA in oncogenesis, stable RNA interference (RNAi)–mediated knockdown of CypA was established in two non–small-cell lung cancer cell lines (ADLC-5M2 and LC-103H), and these cells were grown as xenografts in severe combined immunodeficient mice. Tumor cell proliferation, apoptosis, and angiogenesis were measured by Ki67, terminal deoxyribonucleotidyl transferase–mediated dUTP nick-end labeling, and CD31 immunohistochemistry, respectively. Tumor glucose metabolism was assessed by fluorodeoxyglucose positron emission tomography imaging. Knockdown of CypA correlated in vivo with slower growth, less fluorodeoxyglucose uptake, decreased proliferation, and a greater degree of apoptosis in the tumors. These results establish the relevance of CypA to tumor growth in vivo, specifically to proliferation and apoptosis. Elucidation of the precise role of CypA in these pathways may lead to new targeted therapies for lung cancer.

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.

Hypoxia-inducible factor-1α (HIF-1α) is an important transcriptional factor that is activated when mammalian cells experience hypoxia, a tumor microenvironmental condition that plays pivotal roles in tumor progression and treatment. In this study, we examined the idea of down-regulating HIF-1α in tumor cells for therapeutic gain. We show that the expression levels of HIF-1α can be significantly attenuated by use of the recently established small interfering RNA technology in combination with adenovirus-mediated gene transfer. Down-regulation of the HIF-1α protein enhanced hypoxia-mediated tumor cell apoptosis in vitro. Subcutaneous tumor growth was also prevented from cells with attenuated HIF-1α expression. In addition, intratumoral injection of adenovirus encoding the HIF-1α-targeted small interfering RNA had a small but significant effect on tumor growth when combined with ionizing radiation. Therefore, our results provide proof of HIF-1α as an effective target for anticancer therapy. They also suggest that an adenovirus-based small interfering RNA gene transfer approach may be a potentially effective adjuvant strategy for cancer treatment.

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.

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 macrophage activity and the expression and activation of profibrogenic cytokines. Our results demonstrated a reduction in both functional and histological radiation-induced lung injury by amifostine. In addition, this study is the first to demonstrate that amifostine given prior to irradiation reduced both the accumulation of macrophages and the expression/activation of lung tissue Tgfb1 which was followed by the reduction of plasma Tgfb1 levels during the development of radiation-induced lung injury. Future studies are needed to determine whether administration of amifostine both during and after radiotherapy may further increase its radioprotective effect.

The objective of this study was to assess the radioprotective effects of amifostine in the rat model of radiation-induced lung injury using fractionated doses of radiation, to determine whether amifostine given before irradiation protects tumor from radiation cytotoxicity, and to determine whether changes in plasma levels of transforming growth factor (TGF)-beta correlate with radioprotective effect of amifostine. R3230 AC mammary adenocarcinoma was transplanted on the right posterior chest wall of female Fisher-344 rats. Both tumor-bearing and non-tumor-bearing animals were irradiated to the tumor or right lung using 4 MV photons and fractionated dose of 35 Gy/5 fractions/5 days. Animals with tumors and those without were randomized into 4 groups, respectively (8 to 10 rats per group), to receive (1) radiation alone; (2) radiation + amifostine; (3) amifostine alone; (4) sham radiation. Amifostine (150 mg/kg) was given intraperitoneally 30 minutes before each fraction of irradiation. The tumor size was measured twice a week. Breathing rate was assessed every 2 weeks. TGF-beta levels in plasma were assessed monthly after treatment. Six months after irradiation, animals were euthanized and lung tissue was processed for hydroxyproline content analysis. A significant increase in breathing frequency started 9 weeks after irradiation in animals that received radiation only. In the radiation + amifostine group, there was both a delay and a significantly lower peak in breathing frequency (P < .001). Hydroxyproline content was higher in the radiation-alone group than in rats given amifostine prior to radiation (P < .05). The TGF-beta levels in plasma showed an increase from 1 to 3 months after radiation, peaking at 2 months in the rats with (2.80 +/- 0.23) or without (5.32 +/- 1.21) amifostine compared to sham irradiation. TGF-beta levels were significantly lower at 1 to 3 months in rats receiving amifostine plus radiation versus those receiving radiation alone. Tumor growth delay and regrowth rate after radiation were not different between radiation-alone and radiation + amifostine groups. This study confirms the protective effect of amifostine in reducing radiation-induced pulmonary toxicity. No tumor protection was demonstrated after fractionated radiotherapy. The reduction in pulmonary injury with amifostine in paralleling lower plasma levels of TGF-beta, suggesting that monitoring plasma levels of this cytokine may reflect the efficacy of an intervention aimed at preventing 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.

In an effort to target the in vivo context of tumor-specific moieties, a large library of nuclease-resistant RNA oligonucleotides was screened in tumor-bearing mice to identify candidate molecules with the ability to localize to hepatic colon cancer metastases. One of the selected molecules is an RNA aptamer that binds to protein p68, an RNA helicase that has been shown to be upregulated in colorectal cancer.

Purpose Apoptosis in irradiated normal lung tissue has been observed several weeks after radiation. However, the signaling pathway propagating cell death after radiation remains unknown. Methods and Materials C57BL/6J mice were irradiated with 15 Gy to the whole thorax. Pro-apoptotic signaling was evaluated 6 weeks after radiation with or without administration of AEOL10150, a potent catalytic scavenger of reactive oxygen and nitrogen species. Results Apoptosis was observed primarily in type I and type II pneumocytes and endothelium. Apoptosis correlated with increased PTEN expression, inhibition of downstream PI3K/AKT signaling, and increased p53 and Bax protein levels. Transforming growth factor-β1, Nox4, and oxidative stress were also increased 6 weeks after radiation. Therapeutic administration of AEOL10150 suppressed pro-apoptotic signaling and dramatically reduced the number of apoptotic cells. Conclusion Increased PTEN signaling after radiation results in apoptosis of lung parenchymal cells. We hypothesize that upregulation of PTEN is influenced by Nox4-derived oxidative stress. To our knowledge, this is the first study to highlight the role of PTEN in radiation-induced pulmonary toxicity.

Hypoxia, a pathological feature of many solid tumours, is caused by an imbalance between tumour proliferation and angiogenesis (Dang and Semenza, 1999; Dewhirst et al, 2008). Hypoxic regions are defined by an oxygen tension (pO2) of ⩽10 mm Hg. They have been identified in up to 50% of locally advanced breast tumours (Vaupel et al, 2002), and the presence of hypoxia is known to be a negative predictor of survival in cancer patients as it may contribute to more aggressive tumour phenotypes, increased invasiveness, and metastasis (Harris, 2002). The transmembrane glycoprotein carbonic anhydrase IX (CA IX) has been identified as a potentially important marker of hypoxia in breast tumours. Known to catalyse the transformation of carbon dioxide to carbonic acid, CA IX may contribute to acidification of the extracellular microenvironment in a variety of tumours (Pastorek et al, 1994; Lindskog, 1997). Expression of CA IX is dependent on the transcription factor hypoxia-inducible factor-1 (HIF-1) (Wykoff et al, 2000), and the presence or absence of CA IX is correlated with microelectrode measurements of tumour oxygenation in cervical carcinoma (Loncaster et al, 2001). Immunohistochemical studies demonstrate that CA IX co-localises with pimonidazole, a bioreductive marker of hypoxia (Olive et al, 2001). Although CA IX is widely accepted as a marker of tumour hypoxia, its prognostic significance remains the subject of significant debate (Chia et al, 2001; Bartosova et al, 2002; Span et al, 2003; Brennan et al, 2006). The differing conclusions in these studies may be explained by the fact that heterogeneous patient populations have been treated with different combinations of surgery, radiation, and chemotherapy. Breast cancer is the most common malignancy affecting women today aside from non-melanoma skin cancer, and it trails only lung cancer as the most common cause of cancer death in females (Jemal et al, 2008). Although standard surgical and radiotherapy techniques have resulted in over 95% local control of primary breast tumours (Bartelink et al, 2001), the 10-year overall survival (OS) rate still hovers just above 80% because of failures of local and systemic therapies (Navalta et al, 2010). Although surgery remains the mainstay of early-stage breast cancer treatment, approaches involving adjuvant chemotherapy are increasing. In early stage disease, adjuvant chemotherapy provides only a modest survival benefit while causing significant systemic toxicity and patient suffering. Thus, there is considerable interest in identifying predictive markers of response to chemotherapy to enable clinicians to select agents most likely to benefit a given patient and avoid ineffectual treatments. Hypoxia is also widely accepted to have a role in resistance to radiotherapy and chemotherapy in a variety of human tumours. Anthracyclines, a group of chemotherapeutic agents that inhibit topoisomerase IIα, are the most common chemotherapeutic agents used worldwide to treat breast cancer. Under hypoxic conditions, cancer cells experience a large pH gradient across the cellular membrane, maintaining acidic extracellular and basic intracellular environments (Svastova et al, 2004). The acidic extracellular environment can decrease the uptake of anthracyclines by cells, because these drugs are weak bases, which ionise at low pH (Gerweck and Seetharaman, 1996). Furthermore, one of the mechanisms by which anthracyclines mediate cellular death is through iron-mediated generation of reactive oxygen species (ROS). As ROS formation is dependent on the presence of oxygen within the tumour microenvironment, anthracyclines may be less effective in hypoxic tumours. To address this potential disparity in therapeutic effectiveness, we gathered a set of early-stage breast cancer biopsies from patients who received anthracycline-based chemotherapeutic regimens and had >10 years of follow-up. Using immunohistochemical detection of CA IX, we demonstrate that tumour hypoxia is correlated with worse outcome for early-stage breast cancer patients treated with doxorubicin. Further, we found CA IX to predict outcome, independent of human epidermal growth factor receptor 2 (HER2) and DNA topoisomerase II-alpha (TOP2A) gene amplification.

The aim of this study is to investigate the tumor tissue changes in terms of hypoxia and demonstrate its relationship to vascularity and apoptosis following therapeutic cryoablation in a prostate tumor murine model. Total 67 male C57BL/J6 mice were assigned into sham-operation group and cryoablation group. Murine prostate tumors (RM-9) were inoculated subcutaneously in a right hind leg and treated with cryotherapy. Of 30 mice, tumor volumes were measured for 12 days following operation. Of 37 mice, tumor tissues were harvested in 24 h following operation, and histological/molecular changes were analyzed. Hematoxylin and eosin or immunohistochemical staining were utilized to quantify tumor necrosis, hypoxia (pimonidazole), vascularization (CD31), and apoptosis (cleaved caspase-3). The results showed that cryoablated tumors demonstrated significant delayed growth following treatment compared to controls. Pathological analysis revealed that the severity of hypoxia increased in the cryoablation arm compared to controls. Necrotic and apoptotic populations were also found to be increased in the cryoablation arm (P = 0.028 and 0.021). Hypoxia demonstrated a positive correlation with necrosis (r = 0.520, P = 0.001) and apoptosis (r = 0.474, P = 0.003), while showing negative correlation with microvessel density (MVD) (r = −0.361, P = 0.021). We concluded that in the peripheral areas from the cryoneedle impact site, strong hypoxic responses were found, which may play important role in tumor freezing injury. To our knowledge, this is the first report describing cryoablation-mediated changes of hypoxia at a molecular level in the prostate cancer murine model.

To investigate the relationship of HIF1alpha signaling to oxidative stress, tissue hypoxia, angiogenesis and inflammation, female Fischer 344 rats were irradiated to the right hemithorax with a fractionated dose of 40 Gy (8 Gy x 5 days). The lung tissues were harvested before and at 4, 6, 10, 14, 18, 22 and 26 weeks after irradiation for serial studies of biological markers, including markers for hypoxia (HIF1alpha, pimonidazole and CA IX), oxidative stress (8-OHdG), and angiogenesis/capillary proliferation (VEGF/CD 105), as well as macrophage activation (ED-1) and cell signaling/fibrosis (NFkappaB, TGFbeta1), using immunohistochemistry and Western blot analysis. HIF1alpha staining could be observed as early as 4 weeks postirradiation and was significantly increased with time after irradiation. Importantly, HIF1alpha levels paralleled oxidative stress (8-OHdG), tissue hypoxia (pimonidazole and CA IX), and macrophage accumulation consistent with inflammatory response. Moreover, changes in HIF1alpha expression identified by immunohistochemistry assay parallel the changes in TGFbeta1, VEGF, NFkappaB and CD 105 levels in irradiated lungs. These results support the notion that oxidative stress and tissue hypoxia might serve as triggering signals for HIF1alpha activity in irradiated lungs, relating to radiation-induced inflammation, angiogenesis and fibrosis.

Tumor hypoxia is associated with adverse outcome in many malignancies. The goal of this study was to determine if elevated expression of carbonic anhydrase IX (CAIX), a biomarker of hypoxia, predicts for recurrence in early-stage cervical cancer. The charts of all patients with early-stage cervical cancer, primarily FIGO IB, treated by radical hysterectomy at our institution from 1988–2001 were reviewed. Adequate pathologic specimens from patients who recurred or who had at least three years follow-up and remained disease-free were stained for CAIX. An immunohistochemical score (IHC) was generated from the extent/intensity of staining. Outcome, as measured by freedom from recurrence (FFR), distant metastases (FFDM) and local recurrence (FFLR), was analyzed as a function of age, IHC, lymph node status (LN) and histology. Forty-two relapsing patients and 76 non-relapsing patients were evaluated. In univariate analysis, +LN, though not IHC or histology, was a significant predictor of any recurrence. Both +LN and higher IHC were associated with decreased FFDM but not FFLR. Patients with both +LN and elevated IHC more frequently exhibited distant metastases as first site of failure (5-year FFDM 50%) than patients with only +LN, elevated IHC or neither feature (70, 85 and 95%, respectively, p = 0.0004). In multivariable analysis, only +LN was significantly associated with poorer FFDM (hazard ratio 4.6, p = 0.0015) though there was a strong trend with elevated CAIX expression (p = 0.069). Elevated CAIX expression is associated with more frequent distant metastases in early-stage cervical cancer, suggesting that patients with this characteristic may benefit from more aggressive treatment.

Tumors contain oxygenated and hypoxic regions, so the tumor cell population is heterogeneous. Hypoxic tumor cells primarily use glucose for glycolytic energy production and release lactic acid, creating a lactate gradient that mirrors the oxygen gradient in the tumor. By contrast, oxygenated tumor cells have been thought to primarily use glucose for oxidative energy production. Although lactate is generally considered a waste product, we now show that it is a prominent substrate that fuels the oxidative metabolism of oxygenated tumor cells. There is therefore a symbiosis in which glycolytic and oxidative tumor cells mutually regulate their access to energy metabolites. We identified monocarboxylate transporter 1 (MCT1) as the prominent path for lactate uptake by a human cervix squamous carcinoma cell line that preferentially utilized lactate for oxidative metabolism. Inhibiting MCT1 with alpha-cyano-4-hydroxycinnamate (CHC) or siRNA in these cells induced a switch from lactate-fueled respiration to glycolysis. A similar switch from lactate-fueled respiration to glycolysis by oxygenated tumor cells in both a mouse model of lung carcinoma and xenotransplanted human colorectal adenocarcinoma cells was observed after administration of CHC. This retarded tumor growth, as the hypoxic/glycolytic tumor cells died from glucose starvation, and rendered the remaining cells sensitive to irradiation. As MCT1 was found to be expressed by an array of primary human tumors, we suggest that MCT1 inhibition has clinical antitumor potential.

To determine whether an anti-transforming growth factor-beta (TGF-beta) type 1 receptor inhibitor (SM16) can prevent radiation-induced lung injury.One fraction of 28 Gy or sham radiotherapy (RT) was administered to the right hemithorax of Sprague-Dawley rats. SM16 was administered in the rat chow (0.07 g/kg or 0.15 g/kg) beginning 7 days before RT. The rats were divided into eight groups: group 1, control chow; group 2, SM16, 0.07 g/kg; group 3, SM16, 0.15 g/kg; group 4, RT plus control chow; group 5, RT plus SM16, 0.07 g/kg; group 6, RT plus SM16, 0.15 g/kg; group 7, RT plus 3 weeks of SM16 0.07 g/kg followed by control chow; and group 8, RT plus 3 weeks of SM16 0.15 g/kg followed by control chow. The breathing frequencies, presence of inflammation/fibrosis, activation of macrophages, and expression/activation of TGF-beta were assessed.The breathing frequencies in the RT plus SM16 0.15 g/kg were significantly lower than the RT plus control chow from Weeks 10-22 (p0.05). The breathing frequencies in the RT plus SM16 0.07 g/kg group were significantly lower only at Weeks 10, 14, and 20. At 26 weeks after RT, the RT plus SM16 0.15 g/kg group experienced a significant decrease in lung fibrosis (p = 0.016), inflammatory response (p = 0.006), and TGF-beta1 activity (p = 0.011). No significant reduction was found in these measures of lung injury in the group that received SM16 0.7 g/kg nor for the short-course (3 weeks) SM16 at either dose level.SM16 at a dose of 0.15 g/kg reduced functional lung damage, morphologic changes, inflammatory response, and activation of TGF-beta at 26 weeks after RT. The data suggest a dose response and also suggest the superiority of long-term vs. short-term dosing.

Due to the prevalence of tumor chemoresistance, the clinical response of advanced non-small cell lung cancer (NSCLC) to chemotherapy is poor. We suppressed tumor resistance to doxorubicin (Dox) in A549 cells, a human NSCLC cell line, both in vitro and in vivo in a lung tumor xenograft model, using a novel adenoviral expression system to deliver an RNA aptamer (A-p50) that specifically inhibits nuclear factor-kappaB (NF-kappaB) activation. By achieving selective, targeted, and early inhibition of NF-kappaB activity, we demonstrate that NF-kappaB plays a critical role in Dox-induced chemoresistance by regulating genes involved in proliferation (Ki-67), response to DNA damage (GADD153), antiapoptosis (Bcl-XL), and pH regulation (CA9). This Dox-induced NF-kappaB activation and subsequent chemoresistance is dependent on expression of p53. We also demonstrate that NF-kappaB promotes angiogenesis in the presence of Dox via the hypoxia-inducible factor-1alpha/vascular endothelial growth factor (HIF-1alpha/VEGF) pathway, revealing a previously unknown mechanism of NSCLC resistance to Dox. These studies provide important insights into the mechanisms of Dox-induced chemoresistance, and they demonstrate a novel, effective, and clinically practical strategy for interfering with these processes.

Background The induction of tumor angiogenesis, a pathologic process critical for tumor progression, is mediated by multiple regulatory factors released by tumor and host cells. We investigated the role of the hematopoietic cytokine erythropoietin as an angiogenic factor that modulates tumor progression. Methodology/Principal Findings Fluorescently-labeled rodent mammary carcinoma cells were injected into dorsal skin-fold window chambers in mice, an angiogenesis model that allows direct, non-invasive, serial visualization and real-time assessment of tumor cells and neovascularization simultaneously using intravital microscopy and computerized image analysis during the initial stages of tumorigenesis. Erythropoietin or its antagonist proteins were co-injected with tumor cells into window chambers. In vivo growth of cells engineered to stably express a constitutively active erythropoietin receptor EPOR-R129C or the erythropoietin antagonist R103A-EPO were analyzed in window chambers and in the mammary fat pads of athymic nude mice. Co-injection of erythropoietin with tumor cells or expression of EPOR-R129C in tumor cells significantly stimulated tumor neovascularization and growth in window chambers. Co-injection of erythropoietin antagonist proteins (soluble EPOR or anti-EPO antibody) with tumor cells or stable expression of antagonist R103A-EPO protein secreted from tumor cells inhibited angiogenesis and impaired tumor growth. In orthotopic tumor xenograft studies, EPOR-R129C expression significantly promoted tumor growth associated with increased expression of Ki67 proliferation antigen, enhanced microvessel density, decreased tumor hypoxia, and increased phosphorylation of extracellular-regulated kinases ERK1/2. R103A-EPO antagonist expression in mammary carcinoma cells was associated with near-complete disruption of primary tumor formation in the mammary fat pad. Conclusions/Significance These data indicate that erythropoietin is an important angiogenic factor that regulates the induction of tumor cell-induced neovascularization and growth during the initial stages of tumorigenesis. The suppression of tumor angiogenesis and progression by erythropoietin blockade suggests that erythropoietin may constitute a potential target for the therapeutic modulation of angiogenesis in cancer.

Prolonged activation of NF-kappaB is involved in the pathogenesis of chronic inflammatory diseases and associated cancers. NF-kappaB activation is considered to be a main mechanism opposing TNFalpha-induced apoptosis. We investigated whether inhibition of NF-kappaB could sensitize tumor and endothelial cells to TNFalpha-induced apoptosis. As such, we developed a novel H1 RNA polymerase III promoter driven adenoviral vector to express an RNA aptamer, Ad-A-p50, which selectively inhibits NF-kappaB activation in the nucleus. This event sensitizes human lung adenocarcinoma cells (A549) and human endothelial cells (HUVEC) to TNFalpha-induced apoptosis through the multiple pathways regulated by NF-kappaB, including Bcl-XL, HIF-1alpha, and VEGF. Our findings also suggest a new mechanism of HIF-1alpha regulation by NF-kappaB in the normoxic environment. RNA aptamer inhibition of NF-kappaB offers exciting opportunities for sensitizing inflammatory and tumor cells to TNFalpha-induced apoptosis.

Recent advances in our understanding of the molecular events leading to the development of normal tissue complications after radiotherapy has led to an effort to identify biological markers that could identify patients at increased or decreased risk for treatment related injury. The goal of this effort is to improve the therapeutic ratio and enable physicians to optimize therapy for individual patients. In radiotherapy of the thoracic region, the lung is one of the most critical dose-limiting organs. This review briefly introduces the mechanisms of radiation-induced lung injury and gives a summary of clinical research focused on evaluating changes in biological markers before, during, and after radiation therapy of the thorax.

Tumor necrosis factor-α (TNF-α) is an important inflammation cytokine without known direct effect on DNA. In this study, we found that TNF-α can cause DNA damages through reactive oxygen species. The mutagenic effect of TNF-α is comparable with that of ionizing radiation. TNF-α treatment in cultured cells resulted in increased gene mutations, gene amplification, micronuclei formation, and chromosomal instability. Antioxidants significantly reduced TNF-α–induced genetic damage. TNF-α also induced oxidative stress and nucleotide damages in mouse tissues in vivo. Moreover, TNF-α treatment alone led to increased malignant transformation of mouse embryo fibroblasts, which could be partially suppressed by antioxidants. As TNF-α is involved in chronic inflammatory diseases, such as chronic hepatitis, ulcerative colitis, and chronic skin ulcers, and these diseases predispose the patients to cancer development, our results suggest a novel pathway through which TNF-α promotes cancer development through induction of gene mutations, in addition to the previously reported mechanisms, in which nuclear factor-κB activation was implicated. (Cancer Res 2006; 66(24): 11565-70)

Purpose: To investigate the temporal onset of hypoxia following irradiation, and to show how it relates to pulmonary vascular damage, macrophage accumulation, and the production of reactive oxygen species and cytokines. Our previous studies showed that tissue hypoxia in the lung after irradiation contributed to radiation-induced injury. Methods and Materials: Female Fisher 344 rats were irradiated to the right hemithorax with a single dose of 28 Gy. Serial studies were performed up to 20 weeks following irradiation. Radionuclide lung-perfusion studies were performed to detect changes in pulmonary vasculature. Immunohistochemical studies were conducted to study macrophages, tissue hypoxia (carbonic anhydrase-9 marker), oxidative stress (8-hydroxy-2′-deoxyguanosine), and the expression of profibrogenic (transforming growth factor-β [TGF-β]) and proangiogenic (vascular endothelial growth factor [VEGF]) cytokines. Results: Significant changes in lung perfusion along with tissue hypoxia were observed 3 days after irradiation. Significant oxidative stress was detected 1 week after radiation, whereas macrophages started to accumulate at 4 weeks. A significant increase in TGF-β expression was seen within 1 day after radiation, and for VEGF at 2 weeks after radiation. Levels of hypoxia, oxidative stress, and both cytokines continued to rise with time after irradiation. The steepest increase correlated with vast macrophage accumulation. Conclusions: Early changes in lung perfusion, among other factors initiate, the development of hypoxia and chronic oxidative stress after irradiation. Tissue hypoxia is associated with a significant increase in the activation of macrophages and their continuous production of reactive oxygen species, stimulating the production of fibrogenic and angiogenic cytokines, and maintaining the development of chronic radiation-induced lung injury.

Elevated intratumoral interstitial fluid pressure (IFP) and tumour hypoxia are independent predictive factors for poor survival and poor treatment response in cancer patients. However, the relationship between IFP and tumour hypoxia has not yet been clearly established. Preclinical studies have shown that lowering IFP improves treatment response to cytotoxic therapy. Interstitial fluid pressure can be reduced by inhibition of phosphorylated platelet-derived growth factor receptor-beta (p-PDGFR-beta), a tyrosine kinase receptor frequently overexpressed in cancer stroma, and/or by inhibition of VEGF, a growth factor commonly overexpressed in tumours overexpressing p-PDGFR-beta. We hypothesised that Imatinib, a specific PDGFR-beta inhibitor will, in addition to p-PDGFR-beta inhibition, downregulate VEGF, decrease IFP and improve tumour oxygenation. A549 human lung adenocarcinoma xenografts overexpressing PDGFR-beta were grown in nude mice. Tumour-bearing animals were randomised to control and treatment groups (Imatinib 50 mg kg(-1) via gavage for 4 days). Interstitial fluid pressure was measured in both groups before and after treatment. EF5, a hypoxia marker, was administered 3 h before being killed. Tumours were sectioned and stained for p-PDGFR-beta, VEGF and EF5 binding. Stained sections were viewed with a fluorescence microscope and image analysis was performed. Imatinib treatment resulted in significant reduction of p-PDGFR-beta, VEGF and IFP. Tumour oxygenation was also significantly improved. This study shows that p-PDGFR-beta-overexpressing tumours can be effectively treated with Imatinib to decrease tumour IFP. Importantly, this is the first study demonstrating that Imatinib treatment improves tumour oxygenation and downregulates tumour VEGF expression.

Evidence for erythropoietin signaling has been shown in several nonhematopoietic tissues, including many tumor types. Clinically, recombinant erythropoietin treatment of malignancy-related anemia has yet to be definitively associated with any modulation of chemotherapy or radiotherapy efficacy. Preclinically, recombinant erythropoietin has been shown to increase tumor oxygenation, but the direct effects of recombinant erythropoietin on tumor cells that express erythropoietin receptor are not yet fully characterized. This study examined the effects of exogenous recombinant erythropoietin on rodent mammary adenocarcinoma cells (R3230) in vitro and in vivo, and determined the effects of systemic recombinant erythropoietin on tumor growth delay in Taxol treatment. We showed that systemic recombinant erythropoietin treatment of rats bearing R3230 mammary carcinomas induced an increase in phospho-Akt levels within tumor cells. This was associated with a decrease in the frequency of apoptotic cells in tumors from recombinant erythropoietin–treated animals, but did not noticeably affect tumor growth rate. In vitro studies revealed that not only does recombinant erythropoietin induce Akt phosphorylation, but it also stimulates phosphorylation of p44/42 mitogen-activated protein kinases, Erk1 and Erk2. Activation of erythropoietin-mediated signaling in R3230 cells was associated with dose-dependent inhibition of apoptosis in response to Taxol treatment and serum starvation, an effect that was blocked by the addition of a phosphatidylinositol-3-kinase inhibitor. Despite its cytoprotective effects in vitro, recombinant erythropoietin did not significantly affect tumor growth delay in Taxol treatment. This study shows direct recombinant erythropoietin–mediated activation of specific intracellular signaling pathways in mammary adenocarcinoma cells in vivo and in vitro. Modulation of tumor apoptosis pathways by recombinant erythropoietin may have negative consequences by decreasing the chemosensitivity and radiosensitivity of erythropoietin receptor–positive breast tumors, although it did not have any obvious effects on growth with or without chemotherapy in this model. [Mol Cancer Ther 2006;5(2):356–61]