Intercellular communications-redox interactions in radiation toxicity; potential targets for radiation mitigation

An unmet need for pharmacology: Treatments for radiation-induced gastrointestinal mucositis

Gastrointestinal mucositis (GIM) continues to be a significant issue in the management of abdominal cancer radiation treatments and chemotherapy, causing significant patient discomfort and therapy interruption or even cessation. This review will first focus on radiotherapy induced GIM, providing an understanding of its clinical landscape. Subsequently, the aetiology of GIM will be reviewed, highlighting diverse contributing factors. The cellular and tissue damage and associated molecular responses in GIM will be summarised in the context of the underlying complex biological processes. Finally, available drugs and pharmaceutical therapies will be evaluated, underscoring their insufficiency, and highlighting the need for further research and innovation. This review will emphasize the urgent need for improved pharmacologic therapeutics for GIM, which is a key research priority in oncology.

Intercellular pathways of cancer treatment-related cardiotoxicity and their therapeutic implications: The paradigm of radiotherapy

Advances in cancer therapeutics have improved patient survival rates. However, cancer survivors may suffer from adverse events either at the time of therapy or later in life. Cardiovascular diseases (CVD) represent a clinically important, but mechanistically understudied complication, which interfere with the continuation of best-possible care, induce life-threatening risks, and/or lead to long-term morbidity. These concerns are exacerbated by the fact that targeted therapies and immunotherapies are frequently combined with radiotherapy, which induces durable inflammatory and immunogenic responses, thereby providing a fertile ground for the development of cardiovascular diseases (CVDs). Stressed and dying irradiated cells produce 'danger' signals including, but not limited to, major histocompatibility complexes, cell-adhesion molecules, proinflammatory cytokines, and damage-associated molecular patterns. These factors activate intercellular signaling pathways which have potentially detrimental effects on the heart tissue homeostasis. Herein, we present the clinical crosstalk between cancer and heart diseases, describe how it is potentiated by cancer therapies, and highlight the multifactorial nature of the underlying mechanisms. We particularly focus on radiotherapy, as a case known to often induce cardiovascular complications even decades after treatment. We provide evidence that the secretome of irradiated tumors entails factors that exert systemic, remote effects on the cardiac tissue, potentially predisposing it to CVDs. We suggest how diverse disciplines can utilize pertinent state-of-the-art methods in feasible experimental workflows, to shed light on the molecular mechanisms of radiotherapy-related cardiotoxicity at the organismal level and untangle the desirable immunogenic properties of cancer therapies from their detrimental effects on heart tissue. Results of such highly collaborative efforts hold promise to be translated to next-generation regimens that maximize tumor control, minimize cardiovascular complications, and support quality of life in cancer survivors.

Tetrahydrobiopterin metabolism attenuates ROS generation and radiosensitivity through LDHA S-nitrosylation: novel insight into radiogenic lung injury

Genotoxic therapy triggers reactive oxygen species (ROS) production and oxidative tissue injury. S-nitrosylation is a selective and reversible posttranslational modification of protein thiols by nitric oxide (NO), and 5,6,7,8-tetrahydrobiopterin (BH4) is an essential cofactor for NO synthesis. However, the mechanism by which BH4 affects protein S-nitrosylation and ROS generation has not been determined. Here, we showed that ionizing radiation disrupted the structural integrity of BH4 and downregulated GTP cyclohydrolase I (GCH1), which is the rate-limiting enzyme in BH4 biosynthesis, resulting in deficiency in overall protein S-nitrosylation. GCH1-mediated BH4 synthesis significantly reduced radiation-induced ROS production and fueled the global protein S-nitrosylation that was disrupted by radiation. Likewise, GCH1 overexpression or the administration of exogenous BH4 protected against radiation-induced oxidative injury in vitro and in vivo. Conditional pulmonary Gch1 knockout in mice (Gch1fl/fl; Sftpa1-Cre+/- mice) aggravated lung injury following irradiation, whereas Gch1 knock-in mice (Gch1lsl/lsl; Sftpa1-Cre+/- mice) exhibited attenuated radiation-induced pulmonary toxicity. Mechanistically, lactate dehydrogenase (LDHA) mediated ROS generation downstream of the BH4/NO axis, as determined by iodoacetyl tandem mass tag (iodoTMT)-based protein quantification. Notably, S-nitrosylation of LDHA at Cys163 and Cys293 was regulated by BH4 availability and could restrict ROS generation. The loss of S-nitrosylation in LDHA after irradiation increased radiosensitivity. Overall, the results of the present study showed that GCH1-mediated BH4 biosynthesis played a key role in the ROS cascade and radiosensitivity through LDHA S-nitrosylation, identifying novel therapeutic strategies for the treatment of radiation-induced lung injury.

Design, synthesis, biological evaluation and in silico studies of novel quinoline derivatives as potential radioprotective molecules targeting the TLR2 and p53 pathways

Ionizing radiation in space, radiation devices or nuclear disasters are major threats to human health and public security. In this paper, in order to find the potential novel compounds decreasing the radiation-induced damage by targeting p53 apoptosis pathway and TLR2 passway, a series of novel quinoline derivatives were designed, synthesized, and evaluated their biological activities. Most of the synthesized compounds showed significant radioprotective effects in vitro, and the compound 5 has the best performance. Therefore, we verified its radioprotective activity in vivo and investigated the mechanism of its excellent activity. The results in vivo indicated that compound 5 not only markedly enhanced the survival rate (80 %) of mice 30 days after lethal exposure to irradiation, but also significantly reduced the radiation-induced damage to haematopoietic system and intestinal tissue of mice. The mechanistic studies indicated that compound 5 acted on the p53 pathway to reduce radiation-induced cell apoptosis and at the same time stimulated TLR2 to up-regulate the expressions of radiation protection factors. Molecular dynamics study shows that compound 5 would effectively bind to the TLR2 protein and further revealed the binding mechanism. Taken together, all the findings of our study demonstrate the quinoline derivative 5 is a potent radioprotective compound, which holds a great therapeutic potential for further development.

Fraxin (7-hydroxy-6-methoxycoumarin 8-glucoside) confers protection against ionizing radiation-induced intestinal epithelial injury in vitro and in vivo

The small intestine exhibits remarkable sensitivity to ionizing radiation (IR), which significantly hampers the effectiveness of radiotherapy in the treatment of abdominal and pelvic tumors. Unfortunately, no effective medications are available to treat radiation-induced intestinal damage (RIID). Fraxin (7-hydroxy-6-methoxycoumarin 8-glucoside), is a coumarin derivative extracted from the Chinese herb Cortex Fraxini. Several studies have underscored the anti-inflammatory, antibacterial, antioxidant, and immunomodulatory properties of fraxin. However, the efficacy of fraxin at preventing or mitigating RIID remains unclear. Thus, the present study aimed to investigate the protective effects of fraxin against RIID in vitro and in vivo and to elucidate the underlying mechanisms. The study findings revealed that fraxin markedly ameliorated intestinal injuries induced by 13 Gy whole abdominal irradiation (WAI), which was accompanied by a significant increase in the population of Lgr5+ intestinal stem cells (ISCs) and Ki67+ progeny. Furthermore, fraxin mitigated WAI-induced intestinal barrier damage, and reduced oxidative stress and intestinal inflammation in mice. Transcriptome sequencing of fraxin-treated mice revealed upregulation of IL-22, a pleiotropic cytokine involved in regulating the function of intestinal epithelial cells. Moreover, in both human intestinal epithelial cells and ex vivo cultured mouse intestinal organoids, fraxin effectively ameliorated IR-induced damage by promoting the expression of IL-22. The radioprotective effects of fraxin were partially negated in the presence of an IL-22-neutralizing antibody. In summary, fraxin is demonstrated to possess the ability to alleviate RIID and maintain intestinal homeostasis, suggesting that fraxin might serve as a strategy for mitigating accidental radiation exposure- or radiotherapy-induced RIID.

Approaches for reducing chemo/radiation-induced cardiotoxicity by nanoparticles

Nanoparticles are fascinating and encouraging carriers for cancer treatment due to their extraordinary properties and potential applications in targeted drug delivery, treatment, and diagnosis. Experimental studies including in vitro and in vivo examinations show that nanoparticles can cause a revolution in different aspects of cancer therapy. Normal tissue toxicity and early and late consequences are the major limitations of cancer therapy by radiotherapy and chemotherapy. However, the delivery of drugs into tumors or reducing the accumulation of drugs in normal tissues can permit a more satisfactory response of malignancies to therapy with more inferior side effects. Cardiac toxicity is one of the major problems for chemotherapy and radiotherapy. Therefore, several experimental studies have been performed to minimize the degenerative impacts of cancer treatment on the heart and also enhance the influences of radiotherapy and chemotherapy agents in cancers. This review article emphasizes the benefits of nanoparticle-based drug delivery techniques, including minimizing the exposure of the heart to anticancer drugs, enhancing the accumulation of drugs in cancers, and expanding the effectiveness of radiotherapy. The article also discusses the challenges and problems accompanied with nanoparticle-based drug delivery techniques such as toxicity, which need to be addressed through further research. Moreover, the article emphasizes the importance of developing safe and effective nanoparticle-based therapies that can be translated into clinical practice.

The diverse effects of cisplatin on tumor microenvironment: Insights and challenges for the delivery of cisplatin by nanoparticles

Cisplatin is a well-known platinum-based chemotherapy medication that is widely utilized for some malignancies. Despite the direct cytotoxic consequences of cisplatin on tumor cells, studies in the recent decade have revealed that cisplatin can also affect different cells and their secretions in the tumor microenvironment (TME). Cisplatin has complex impacts on the TME, which may contribute to its anti-tumor activity or drug resistance mechanisms. These regulatory effects of cisplatin play a paramount function in tumor growth, invasion, and metastasis. This paper aims to review the diverse impacts of cisplatin and nanoparticles loaded with cisplatin on cancer cells and also non-cancerous cells in TME. The impacts of cisplatin on immune cells, tumor stroma, cancer cells, and also hypoxia will be discussed in the current review. Furthermore, we emphasize the challenges and prospects of using cisplatin in combination with other adjuvants and therapeutic modalities that target TME. We also discuss the potential synergistic effects of cisplatin with immune checkpoint inhibitors (ICIs) and other agents with anticancer potentials such as polyphenols and photosensitizers. Furthermore, the potential of nanoparticles for targeting TME and better delivery of cisplatin into tumors will be discussed.

Protection against cancer therapy-induced cardiovascular injury by planed-derived polyphenols and nanomaterials

Cancer therapy-induced heart injury is a significant concern for cancer patients undergoing chemotherapy, radiotherapy, immunotherapy, and also targeted molecular therapy. The use of these treatments can lead to oxidative stress and cardiomyocyte damage in the heart, which can result in heart failure and other cardiac complications. Experimental studies have revealed that chemotherapy drugs such as doxorubicin and cyclophosphamide can cause severe side effects such as cardiac fibrosis, electrophysiological remodeling, chronic oxidative stress and inflammation, etc., which may increase risk of cardiac disorders and attacks for patients that underwent chemotherapy. Similar consequences may also be observed for patients that undergo radiotherapy for left breast or lung malignancies. Polyphenols, a group of natural compounds with antioxidant and anti-inflammatory properties, have shown the potential in protecting against cancer therapy-induced heart injury. These compounds have been found to reduce oxidative stress, necrosis and apoptosis in the heart, thereby preserving cardiac function. In recent years, nanoparticles loaded with polyphenols have also provided for the delivery of these compounds and increasing their efficacy in different organs. These nanoparticles can improve the bioavailability and efficacy of polyphenols while minimizing their toxicity. This review article summarizes the current understanding of the protective effects of polyphenols and nanoparticles loaded with polyphenols against cancer therapy-induced heart injury. The article discusses the mechanisms by which polyphenols protect the heart, including antioxidant and anti-inflammation abilities. The article also highlights the potential benefits of using nanoparticles for the delivery of polyphenols.

Adipose-derived stem cells repair radiation-induced chronic lung injury via inhibiting TGF-β1/Smad 3 signaling pathway

To investigate the effect of adipose-derived stem cells (ASCs) transplantation on radiation-induced lung injury (RILI), Sprague-Dawley rats were divided into phosphate-buffered saline (PBS) group, ASCs group, Radiation + PBS group, and Radiation + ASCs group. Radiation + PBS and Radiation + ASCs groups received single dose of 30 Gy X-ray radiation to the right chest. The Radiation + PBS group received 1 mL PBS suspension and Radiation + ASCs group received 1 mL PBS suspension containing 1 × 107 CM-Dil-labeled ASCs. The right lung tissue was collected on Days 30, 90, and 180 after radiation. Hematoxylin-eosin and Masson staining were performed to observe the pathological changes and collagen fiber content in the lung tissue. Immunohistochemistry (IHC) and western blot (WB) were used to detect levels of fibrotic markers collagen I (Collal), fibronectin (FN), as well as transforming growth factor-β1 (TGF-β1), p-Smad 3, and Smad 3. Compared with the non-radiation groups, the radiation groups showed lymphocyte infiltration on Day 30 after irradiation and thickened incomplete alveolar walls, collagen deposition, and fibroplasia on Days 90 and 180. ASCs relieved these changes on Day 180 (Masson staining, P = 0.0022). Compared with Radiation + PBS group, on Day 180 after irradiation, the Radiation + ASCs group showed that ASCs could significantly decrease the expressions of fibrosis markers Collal (IHC: P = 0.0022; WB: P = 0.0087) and FN (IHC: P = 0.0152; WB: P = 0.026) and inhibit the expressions of TGF-β1 (IHC: P = 0.026; WB: P = 0.0152) and p-Smad 3 (IHC: P = 0.0043; WB: P = 0.0087) in radiation-induced injured lung tissue. These indicated that ASCs could relieve RILI by inhibiting TGF-β1/Smad 3 signaling pathway.

The Prophylactic Effect of Vitamin C and Vitamin B12 against Ultraviolet-C-Induced Hepatotoxicity in Male Rats

Ultraviolet C (UVC) devices are an effective means of disinfecting surfaces and protecting medical tools against various microbes, including coronavirus. Overexposure to UVC can induce oxidative stress, damage the genetic material, and harm biological systems. This study investigated the prophylactic efficacy of vitamin C and B12 against hepatotoxicity in UVC-intoxicated rats. Rats were irradiated with UVC (725.76, 967.68, and 1048.36 J/cm²) for 2 weeks. The rats were pretreated with the aforementioned antioxidants for two months before UVC irradiation. The prophylactic effect of vitamins against UVC hepatotoxicity was evaluated by monitoring the alteration of liver enzyme activities, antioxidant status, apoptotic and inflammatory markers, DNA fragmentation, and histological and ultrastructural alterations. Rats exposed to UVC showed a significant increase in liver enzymes, oxidant-antioxidant balance disruption, and increased hepatic inflammatory markers (TNF-α, IL-1β, iNOS, and IDO-1). Additionally, obvious over-expression of activated caspase-3 protein and DNA fragmentation were detected. Histological and ultrastructural examinations verified the biochemical findings. Co-treatment with vitamins ameliorated the deviated parameters to variable degrees. In conclusion, vitamin C could alleviate UVC-induced hepatotoxicity more than vitamin B12 by diminishing oxidative stress, inflammation, and DNA damage. This study could provide a reference for the clinical practice of vitamin C and B12 as radioprotective for workers in UVC disinfectant areas.

Effect of nano-curcumin on various diseases: A comprehensive review of clinical trials

The antioxidant, anti-inflammatory, and antibacterial properties of curcumin have made it a valuable herbal product for improving various disorders, such as COVID-19, cancer, depression, anxiety, osteoarthritis, migraine, and diabetes. Recent research has demonstrated that encapsulating curcumin in nanoparticles might improve its therapeutic effects and bioavailability. To our knowledge, the efficacy of nano-curcumin on different aspects of health and disease has not been summarized in a study. Therefore, this review aimed to evaluate nano-curcumin's efficacy in various diseases based on the findings of clinical trials. In order to review publications focusing on nanocurcumin's impact on various diseases, four databases were searched, including PubMed, Scopus, Web of Science, and Google Scholar. This review highlights the potential benefits of nano-curcumin in improving a wide range of human diseases including COVID-19, neurological disorders, chronic disease, oral diseases, osteoarthritis, metabolic syndrome, and other diseases, especially as an adjunct to standard therapy and a healthy lifestyle.

Lung Pneumonitis and Fibrosis in Cancer Therapy: A Review on Cellular and Molecular Mechanisms

Fibrosis and pneumonitis are the most important side effects of lung tissue following cancer therapy. Radiotherapy and chemotherapy by some drugs, such as bleomycin, can induce pneumonitis and fibrosis. Targeted therapy and immunotherapy also may induce pneumonitis and fibrosis to a lesser extent compared to chemotherapy and radiotherapy. Activation of lymphocytes by immunotherapy or infiltration of inflammatory cells such as macrophages, lymphocytes, neutrophils, and mast cells following chemo/radiation therapy can induce pneumonitis. Furthermore, the polarization of macrophages toward M2 cells and the release of anti-inflammatory cytokines stimulate fibrosis. Lung fibrosis and pneumonitis may also be potentiated by some other changes such as epithelial-mesenchymal transition (EMT), oxidative stress, reduction/oxidation (redox) responses, renin-angiotensin system, and the upregulation of some inflammatory mediators such as a nuclear factor of kappa B (NF-κB), inflammasome, cyclooxygenase-2 (COX-2), and inducible nitric oxide synthase (iNOS). Damages to the lung vascular system and the induction of hypoxia also can induce pulmonary injury following chemo/radiation therapy. This review explains various mechanisms of the induction of pneumonitis and lung fibrosis following cancer therapy. Furthermore, the targets and promising agents to mitigate lung fibrosis and pneumonitis will be discussed.

Redox Interactions in Chemo/Radiation Therapy-induced Lung Toxicity; Mechanisms and Therapy Perspectives

Lung toxicity is a key limiting factor for cancer therapy, especially lung, breast, and esophageal malignancies. Radiotherapy for chest and breast malignancies can cause lung injury. However, systemic cancer therapy with chemotherapy may also induce lung pneumonitis and fibrosis. Radiotherapy produces reactive oxygen species (ROS) directly via interacting with water molecules within cells. However, radiation and other therapy modalities may induce the endogenous generation of ROS and nitric oxide (NO) by immune cells and some nonimmune cells such as fibroblasts and endothelial cells. There are several ROS generating enzymes within lung tissue. NADPH Oxidase enzymes, cyclooxygenase-2 (COX-2), dual oxidases (DUOX1 and DUOX2), and the cellular respiratory system in the mitochondria are the main sources of ROS production following exposure of the lung to anticancer agents. Furthermore, inducible nitric oxide synthase (iNOS) has a key role in the generation of NO following radiotherapy or chemotherapy. Continuous generation of ROS and NO by endothelial cells, fibroblasts, macrophages, and lymphocytes causes apoptosis, necrosis, and senescence, which lead to the release of inflammatory and pro-fibrosis cytokines. This review discusses the cellular and molecular mechanisms of redox-induced lung injury following cancer therapy and proposes some targets and perspectives to alleviate lung toxicity.

Cardiac Remodelling Following Cancer Therapy: A Review

Cardiac remodelling is characterized by abnormal changes in the function and morphological properties such as diameter, mass, normal diameter of cavities, heart shape, fibrosis, thickening of vessels and heart layers, cardiomyopathy, infiltration of inflammatory cells, and some others. These damages are associated with damage to systolic and diastolic abnormalities, damage to ventricular function, and vascular remodelling, which may lead to heart failure and death. Exposure of the heart to radiation or anti-cancer drugs including chemotherapy drugs such as doxorubicin, receptor tyrosine kinase inhibitors (RTKIs) such as imatinib, and immune checkpoint inhibitors (ICIs) can induce several abnormal changes in the heart structure and function through the induction of inflammation and fibrosis, vascular remodelling, hypertrophy, and some others. This review aims to explain the basic mechanisms behind cardiac remodelling following cancer therapy by different anti-cancer modalities.

Nuclear and Radiological Emergencies: Biological Effects, Countermeasures and Biodosimetry

Atomic and radiological crises can be caused by accidents, military activities, terrorist assaults involving atomic installations, the explosion of nuclear devices, or the utilization of concealed radiation exposure devices. Direct damage is caused when radiation interacts directly with cellular components. Indirect effects are mainly caused by the generation of reactive oxygen species due to radiolysis of water molecules. Acute and persistent oxidative stress associates to radiation-induced biological damages. Biological impacts of atomic radiation exposure can be deterministic (in a period range a posteriori of the event and because of destructive tissue/organ harm) or stochastic (irregular, for example cell mutation related pathologies and heritable infections). Potential countermeasures according to a specific scenario require considering basic issues, e.g., the type of radiation, people directly affected and first responders, range of doses received and whether the exposure or contamination has affected the total body or is partial. This review focuses on available medical countermeasures (radioprotectors, radiomitigators, radionuclide scavengers), biodosimetry (biological and biophysical techniques that can be quantitatively correlated with the magnitude of the radiation dose received), and strategies to implement the response to an accidental radiation exposure. In the case of large-scale atomic or radiological events, the most ideal choice for triage, dose assessment and victim classification, is the utilization of global biodosimetry networks, in combination with the automation of strategies based on modular platforms.

Effect of Hydrogen Inhalation Therapy on Hearing Loss of Patients With Nasopharyngeal Carcinoma After Radiotherapy

Objective

To evaluate the clinical efficacy and safety of hydrogen inhalation in improving hearing loss in patients with long-term survival of nasopharyngeal carcinoma after radiotherapy.

Methods

The eustachian tube dysfunction score, pure tone air conduction threshold, bone conduction threshold, the score of tympanogram and otoscope were prospectively observed in patients with deafness after radiotherapy only or combined radiotherapy and chemotherapy for nasopharyngeal carcinoma. Paired t test and one-way analysis of variance were used to analyze the data before and after treatment.

Results

A total of 17 patients were observed. The median time from radiotherapy to now was 228 months, and the median time from the diagnose of deafness to now was 92 months. After 4 weeks of hydrogen inhalation, the score of eustachian tube dysfunction, air conduction and bone conduction hearing thresholds were significantly reduced, P values were 0.0293, 0.0027, 0.0404, respectively. The mean air-bone gap, the score of otoendoscopy and tympanogram were also decreased, but the differences were not significant (P = 0.2079, P = 0.0536, P = 0.1056). Patients with radiotherapy alone and concurrent chemo-radiotherapy had significantly lower air conduction hearing threshold after hydrogen absorption (P = 0.0142, P = 0.0495). The results of air and bone hearing thresholds before, 4 and 12 weeks after hydrogen inhalation showed a descending trend. The air and bone hearing thresholds before hydrogen inhalation were 74.69 ± 27.03 dB and 45.70 ± 21.58 dB, respectively. At the 12th week, the mean values of air and bone hearing thresholds were the lowest, which were 66.88 ± 20.88 dB and 40.94 ± 18.93 dB, respectively, but there was no significant difference in air and bone hearing thresholds among all groups (P = 0.6755, P = 0.7712). After hydrogen inhalation treatment, no adverse reactions such as nosebleed, chest pain, dyspnea, nausea, vomiting, dizziness, earache and allergic reaction were observed.

Conclusion

This is the first prospective study on the effect of hydrogen inhalation on hearing improvement in patients with deafness after radiotherapy/chemotherapy for nasopharyngeal carcinoma, suggesting that continuous hydrogen inhalation may be an alternative rehabilitation therapy for these patients.

Hepatotoxicity and renal toxicity induced by radiation and the protective effect of quercetin in male albino rats

PURPOSE

Although radiation is one of the basic methods commonly used in cancer treatment, it inevitably enters the field of treatment in healthy tissues and is adversely affected by the acute and chronic side effects of radiation. This study evaluated the possible protective effects of quercetin, an antioxidant agent, against liver and kidney damage in rats exposed to a whole-body single dose of radiation (10 Gy of gamma-ray).

MATERIALS AND METHODS

The study groups were formed as control, sham, quercetin, radiation, quercetin + radiation and radiation + quercetin using 60 male Wistar albino (200-250 g, 3 months old) rats, including 10 rats in each group. The gamma-ray provided by the Co60 teletherapy machine was given to the whole body as external irradiation. According to the groups, quercetin was administered to rats at 50 mg/kg/day via oral gavage before or after radiation administration. The rats were sacrificed the day after irradiation and the extracted tissue samples from all groups were compared histologically and immunohistochemically. DNA damage was determined by the neutral comet assay technique. Also, malondialdehyde (MDA) and glutathione peroxidase (GSH) were evaluated in liver and kidney tissues by the ELISA method.

RESULTS

Histopathological changes were observed altered morphology of liver and kidney tissues in the radiation groups. Sinusoidal dilatations, vacuolization, and hepatic parenchyma necrosis in the liver, while in kidneys, glomerular shrinkage, widened Bowman's space, tubular dilatation, and inflammation were evident. TNF-α, IL1-α, HIF1-α, and caspase 3 immunoreactivities in tissues were determined by immunohistochemistry. High caspase 3 positive cell number confirmed apoptosis, the comet parameters were decreased in the quercetin + radiation group. When compared to the control group, the exposure to radiation showed a marked elevation in MDA which was accompanied by high GSH. This damage was reduced in the quercetin + radiation group.

CONCLUSIONS

With the results obtained from the study; Quercetin is thought to have a protective potential against radiation-induced liver and kidney damage due to its radioprotective effect.

Cardiac inflammation and fibrosis following chemo/radiation therapy: mechanisms and therapeutic agents

The incidence of cardiovascular disorders is one of the most concerns among people who underwent cancer therapy. The heart side effects of cancer therapy may occur during treatment to some years after the end of treatment. Some epidemiological studies confirm that heart diseases are one of the most common reasons for mortality among patients that were received treatment for cancer. Experimental studies and also clinical investigations indicate that inflammatory changes such as pericarditis, myocarditis, and also fibrosis are key mechanisms of cardiac diseases following chemotherapy/radiotherapy. It seems that chronic oxidative stress, massive cell death, and chronic overproduction of pro-inflammatory and pro-fibrosis cytokines are the key mechanisms of cardiovascular diseases following cancer therapy. Furthermore, infiltration of inflammatory cells and upregulation of some enzymes such as NADPH Oxidases are a hallmark of heart diseases after cancer therapy. In the current review, we aim to explain how radiation or chemotherapy can induce inflammatory and fibrosis-related diseases in the heart. We will explain the cellular and molecular mechanisms of cardiac inflammation and fibrosis following chemo/radiation therapy, and then review some adjuvants to reduce the risk of inflammation and fibrosis in the heart.

Mitochondrial Translocator Protein (TSPO) Expression in the Brain After Whole Body Gamma Irradiation

The brain’s early response to low dose ionizing radiation, as may be encountered during diagnostic procedures and space exploration, is not yet fully characterized. In the brain parenchyma, the mitochondrial translocator protein (TSPO) is constitutively expressed at low levels by endothelial cells, and can therefore be used to assess the integrity of the brain’s vasculature. At the same time, the inducible expression of TSPO in activated microglia, the brain’s intrinsic immune cells, is a regularly observed early indicator of subtle or incipient brain pathology. Here, we explored the use of TSPO as a biomarker of brain tissue injury following whole body irradiation. Post-radiation responses were measured in C57BL/6 wild type (Tspo^+/+) and TSPO knockout (Tspo^–/–) mice 48 h after single whole body gamma irradiations with low doses 0, 0.01, and 0.1 Gy and a high dose of 2 Gy. Additionally, post-radiation responses of primary microglial cell cultures were measured at 1, 4, 24, and 48 h at an irradiation dose range of 0 Gy-2 Gy. TSPO mRNA and protein expression in the brain showed a decreased trend after 0.01 Gy relative to sham-irradiated controls, but remained unchanged after higher doses. Immunohistochemistry confirmed subtle decreases in TSPO expression after 0.01 Gy in vascular endothelial cells of the hippocampal region and in ependymal cells, with no detectable changes following higher doses. Cytokine concentrations in plasma after whole body irradiation showed differential changes in IL-6 and IL-10 with some variations between Tspo^–/– and Tspo^+/+ animals. The in vitro measurements of TSPO in primary microglial cell cultures showed a significant reduction 1 h after low dose irradiation (0.01 Gy). In summary, acute low and high doses of gamma irradiation up to 2 Gy reduced TSPO expression in the brain’s vascular compartment without de novo induction of TSPO expression in parenchymal microglia, while TSPO expression in directly irradiated, isolated, and thus highly activated microglia, too, was reduced after low dose irradiation. The potential link between TSPO, its role in mitochondrial energy metabolism and the selective radiation sensitivity, notably of cells with constitutive TSPO expression such as vascular endothelial cells, merits further exploration.

Radiation-Induced Bystander Effects of Adipose-Derived Mesenchymal Stem Cells

OBJECTIVE

The interaction of tumor cells with surrounding stem cells such as adipose-derived mesenchymal stem cells (ASCs) would be a crucial mechanism of tumor progression. It has been shown that irradiation can affect tumor microenvironment through different mechanisms. Given that, we aimed to examine the bystander radiation-induced effects of ASCs on different cancer cell lines.

MATERIALS AND METHODS

In this experimental study, ASCs were extracted from five healthy donors, cultured and then irradiated with a 5Gy of gamma radiation. Following 72 hours of incubation, irradiated ASCs-conditioned media (IACM) and non-irradiated ASCs-conditioned media (NIACM) were collected. Following incubation of different cell lines, Jurkat, LNCaP, U87-MG, MDA-MB-231 and MCF-7, in different media, DMEM, NIACM, and IACM, ALDEFLUOR assay and wound healing assays, were conducted. Using quantitative real-time polymerase chain reaction (qRT-PCR), the expression of ATP-binding cassette transporter genes, ABCA1 and ABCG2, was measured in these cell lines.

RESULTS

NIACM significantly increased ALDH activity in MDA-MB-231 cell (P=0.02), while IACM was associated with significant decrease in the LNCaP and MCF-7 cell lines, respectively P=0.02, P=0.03, compared to DMEM as the control. The area of the scratch site was significantly reduced in MDA-MB-231 cells cultured with NIACM compared to DMEM (P=0.04). Furthermore, ABCA1 mRNA expression was considerably decreased in IACM- but not in DMEMtreated LNCaP line (P=0.01).

CONCLUSION

It seems, after exposing to radiation, ASCs modify to prevent tumor development and metastasis through their radiation-induced bystander effects. Therefore, a better understanding of ASCs function in the tumor microenvironment may provide new insights into therapeutic strategies to surmount radio-resistance in cancer treatment.

Targeting of cancer cell death mechanisms by resveratrol: a review

Cancer cell death is the utmost aim in cancer therapy. Anti-cancer agents can induce apoptosis, mitotic catastrophe, senescence, or autophagy through the production of free radicals and induction of DNA damage. However, cancer cells can acquire some new properties to adapt to anti-cancer agents. An increase in the incidence of apoptosis, mitotic catastrophe, senescence, and necrosis is in favor of overcoming tumor resistance to therapy. Although an increase in the autophagy process may help the survival of cancer cells, some studies indicated that stimulation of autophagy cell death may be useful for cancer therapy. Using some low toxic agents to amplify cancer cell death is interesting for the eradication of clonogenic cancer cells. Resveratrol (a polyphenol agent) may affect various signaling pathways related to cell death. It can induce death signals and also downregulate the expression of anti-apoptotic genes. Resveratrol has also been shown to modulate autophagy and induce mitotic catastrophe and senescence in some cancer cells. This review focuses on the important targets and mechanisms for the modulation of cancer cell death by resveratrol.

Targeting of cancer cell death mechanisms by curcumin: Implications to cancer therapy

Cancer is known as a second major cause of death globally. Nowadays, several modalities have been developed for the treatment of cancer. Radiotherapy and chemotherapy are the most common modalities in most countries. However, newer modalities such as immunotherapy and targeted therapy drugs can kill cancer cells with minimal side effects. All anticancer agents work based on the killing of cancer cells. Numerous studies are ongoing to kill cancer cells more effectively without increasing side effects to normal tissues. The combination modalities with low toxic agents are interesting for this aim. Curcumin is one of the most common herbal agents that has shown several anticancer properties. It can regulate immune system responses against cancer. Furthermore, curcumin has been shown to potentiate cell death signalling pathways and attenuate survival signalling pathways in cancer cells. The knowledge of how curcumin induces cell death in cancers can improve therapeutic efficiency. In this review, the regulatory effects of curcumin on different cell death mechanisms and their signalling pathways will be discussed. Furthermore, we explain how curcumin may potentiate the anticancer effects of other drugs or radiotherapy through modulation of apoptosis, mitotic catastrophe, senescence, autophagy and ferroptosis.

Protective rules of natural antioxidants against gamma-induced damage-A review

Phytochemicals accessible in food have demonstrated efficiency against impairment by gamma radiation. The review presented here is an attempt to show the pharmacological outline of the activity of the natural antioxidants and its primary action of molecular mechanism against the damage induced by gamma rays. This research focused on the results of the in vitro dosage of natural antioxidants relationship, and on the correlation of this information with the statistical variables. Moreover, it deliberated the natural compounds which could decrease the unwelcome impacts of gamma radiation and safeguard biological systems from radiation-stimulated genotoxicity. The outcomes indicated that natural compounds can be utilized as an adjunct to orthodox radiotherapy and cultivate it as an effectual drug for the clinical administration of ailments.

Resveratrol for targeting the tumor microenvironment and its interactions with cancer cells

Tumor resistance to therapy modalities is one of the major challenges to the eradication of cancer cells and complete treatment. Tumor includes a wide range of cancer and non-cancer cells that play key roles in the proliferation of cancer cells and suppression of anti-tumor immunity. For overcoming tumor resistance to therapy, it is important to have in-depth knowledge relating to intercellular communications within the tumor microenvironment (TME). TME includes various types of immune cells such as CD4 + T lymphocytes, cytotoxic T lymphocytes (CTLs), natural killer (NK) cells, macrophages, and T regulatory cells (Tregs). Furthermore, some non-immune cells like cancer stem cells (CSCs), mesenchymal stem cells (MSCs), and cancer-associated fibroblasts (CAFs) are involved in the promotion of tumor growth. The interactions between these cells with cancer cells play a key role in tumor growth or inhibition. Resveratrol as a natural agent has shown the ability to modulate the immune system to potentiate anti-tumor immunity and also help to attenuate cancer cells and CSCs resistance. Thus, this review explains how resveratrol can modulate interactions within TME.

Redox interactions-induced cardiac toxicity in cancer therapy

Cancer patients undergoing radiotherapy, chemotherapy, or targeted cancer therapy are exposed to the risk of several side effects because of the heavy production of ROS by ionizing radiation or some chemotherapy drugs. Damages to DNA, mitochondria, membrane and other organelles within normal tissue cells such as cardiomyocytes and endothelial cells lead to the release of some toxins which are associated with triggering inflammatory cells to release several types of cytokines, chemokines, ROS, and RNS. The release of some molecules following radiotherapy or chemotherapy stimulates reduction/oxidation (redox) reactions. Redox reactions cause remarkable changes in the level of reactive oxygen species (ROS) and reactive nitrogen species (RNS). Excessive production of ROS and RNS or suppression of antioxidant defense enzymes leads to damage to critical macromolecules, which may continue for long times. Increased levels of some cytokines and oxidative injury are hallmarks of heart injury following cancer therapy. Redox reactions may be involved in several heart disorders such as fibrosis, cardiomyopathy, and endothelium injury. In the current review, we explain the cellular and molecular mechanisms of redox interactions following radiotherapy, chemotherapy, and targeted cancer therapy. Afterward, we explain the evidence of the involvement of redox reactions in heart diseases.

Protection Against Radiation-Induced Duox1 and Duox2 Upregulation in Rat's Lung Tissues by a Combination of Curcumin and L-Selenomethionine

Background: It has been proposed that increased levels of pro-inflammatory and pro-fibrotic cytokines play a key role in radiation-induced lung injury. Interleukin-4 (IL-4) and IL-13 are two pro-fibrotic cytokines that promote the production of free radicals through stimulation of Duox1 and Duox2. In this experimental study, we aimed to evaluate the expression of IL4Ra1, Duox1, IL13Ra2, and Duox2 genes following rat’s lung irradiation. Objectives: Also, we detected the modulatory effect of a combination of curcumin and L-selenomethionine on the expression of these genes. Methods: Twenty male rats were divided into four groups as G1: control (no treatment or radiation); G2: treatment with a combination of curcumin and L-selenomethionine; G3: radiation; G4: radiation plus a combination of curcumin and L-selenomethionine. sixty-seven days after irradiation, rats were killed for detecting the expression of IL4Ra1, IL13Ra2, Duox1, and Duox2. Results: The results showed no detectable expression for IL13Ra2, while the expression of IL4Ra1, Duox1, and Duox2 was increased. Treatment with a combination of curcumin and L-selenomethionine could attenuate the expression of these genes. Conclusions: This study proposes that upregulation of Duox1 and Duox2 may be involved in radiation-induced lung injury. Treatment with a combination of curcumin and L-selenomethionine may be useful for the mitigation of lung injury through modulation of these genes.

Protection Against Ionizing Radiation-Induced Normal Tissue Damage by Resveratrol: A Systematic Review

The use of some agents as radioprotectors has been evaluated for protection against normal tissue toxicity following exposure to ionizing radiation. Resveratrol, a natural flavonoid, with antioxidant and anti-inflammatory properties has attracted research interests for its radioprotective potential. This study systematically evaluates existing studies to examine the radioprotective effectiveness of resveratrol. A literature search of the electronic databases, including PubMed, Scopus, and Embase was conducted to retrieve articles investigating the protective effect of resveratrol against ionizing radiation-induced damage to normal tissues. The search timeframe ranged from the inception of each database to January 2020. From an initial search of 231 articles, and after the removal of duplicates as well as applying the predetermined inclusion and exclusion criteria, 33 articles were finally included for this systematic review. Results showed promising protective effect of resveratrol against ionizing radiation-induced damage to normal tissues. Furthermore, no adverse effect was observed after administering resveratrol. Resveratrol showed the potential to protect against ionizing radiation-induced damage to normal tissue cells via notable mechanisms, including anti-apoptotic and anti-inflammatory effects. However, further studies on the efficacy of clinical translation of resveratrol would open up more insights, while other gray areas such as the optimal radioprotective dosage of resveratrol requires further investigation. Overall, resveratrol is a potential double-edged sword in cancer therapy while protecting healthy tissues.

The protective role of short-chain fatty acids acting as signal molecules in chemotherapy- or radiation-induced intestinal inflammation

A compelling set of links between chemotherapy- or radiation-induced intestinal inflammation and microbial dysbiosis has emerged. It is the proportional imbalance between pathogenic and beneficial bacteria that aggravates intestinal mucositis. Bacteria that ferment fibers and produce short-chain fatty acids (SCFAs), (such as acetate, propionate, and butyrate) are typically reduced in the mucosa and feces of patients undergoing cancer therapy. In contrast, increasing lipopolysaccharide-producing bacteria result in proinflammatory events by interacting with Toll-like receptors. A collective acceptance is that bacterial metabolites are critical in recovering intestinal homeostasis. We herein review evidence supporting the positive roles carried out by SCFAs. SCFAs, acting as signaling molecules, directly activate G-coupled-receptors and inhibit histone deacetylases. Thus, SCFAs are able to strengthen the gut barrier and regulate immunomodulatory functions. Furthermore, it is possible to reverse intestinal microbial dysbiosis and subsequently suppress the secretion of proinflammatory cytokines by directly applying SCFA-producing bacteria. In addition, anticancer effects of SCFAs have proved in the colorectal cancer. In this review, we discuss microbial dysbiosis and its impact on chemotherapy- or radiation-induced intestinal mucositis. Moreover, we summarize the mechanisms of SCFA production and its effects on intestinal mucositis. This review suggests the therapeutic potential of SCFAs for the management of chemotherapy- or radiation-induced intestinal inflammation.

Molecular hydrogen: A potential radioprotective agent

In recent years, many studies have shown that hydrogen has therapeutic and preventive effects on various diseases. Its selective antioxidant properties were well noticed. Most of the ionizing radiation-induced damage is caused by hydroxyl radicals (OH) from radiolysis of H₂O. Since hydrogen can mitigate such damage through multiple mechanisms, it presents noteworthy potential as a novel radio-protective agent. This review analyses possible mechanisms for hydrogen's radioprotective properties and effective delivery methods. We also look into details of vitro and vivo studies for hydrogen's radioprotective effects, and clinical practices. We conclude that hydrogen has good potential in radio-protection, with evidence that warrants greater research efforts in this field.

Targets for protection and mitigation of radiation injury

Protection of normal tissues against toxic effects of ionizing radiation is a critical issue in clinical and environmental radiobiology. Investigations in recent decades have suggested potential targets that are involved in the protection against radiation-induced damages to normal tissues and can be proposed for mitigation of radiation injury. Emerging evidences have been shown to be in contrast to an old dogma in radiation biology; a major amount of reactive oxygen species (ROS) production and cell toxicity occur during some hours to years after exposure to ionizing radiation. This can be attributed to upregulation of inflammatory and fibrosis mediators, epigenetic changes and disruption of the normal metabolism of oxygen. In the current review, we explain the cellular and molecular changes following exposure of normal tissues to ionizing radiation. Furthermore, we review potential targets that can be proposed for protection and mitigation of radiation toxicity.

Blocking C-Raf alleviated high-dose small-volume radiation-induced epithelial mesenchymal transition in mice lung

The goal of this study was to develop a potential druggable target for lung injury after SABR through the small animal model. Utilising the model, a radiation dose of 70 Gy or 90 Gy was focally (small volume) delivered to the left lung of mice. The highly expressed phosphorylation form of C-Raf was discovered through a protein array experiment, with the protein being extracted from the area of radiated mouse lung tissue, and was confirmed by IHC and western blot. C-Raf activation, along with morphological change and EMT (Epithelial to Mesenchymal Transition) marker expression, was observed after radiation to the mouse type II alveolar cell line MLE-12. C-Raf inhibitor GW5074 was able to reverse the EMT in cells effectively, and was found to be dependent on Twist1 expression. In the animal experiment, pretreatment of GW5074 alleviated EMT and lung injury after 70 Gy radiation was focally delivered to the lung of mice. Conclusively, these results demonstrate that C-Raf inhibitor GW5074 inhibits high-dose small-volume radiation-induced EMT via the C-Raf/Twist1 signalling pathway in mice. Therefore, pharmacological C-Raf inhibitors may be used effectively as inhibitors of SABR-induced lung fibrosis.

Protective Effect of Selenium-L-methionine on Radiation-induced Acute Pneumonitis and Lung Fibrosis in Rat

BACKGROUND

In this study, we aimed to detect the changes in the level of interleukin (IL)-4 and IL-13 cytokines and their downstream genes including interleukin-13 receptor subunit alpha-2 (IL13Ra2), interleukin-4 receptor subunit alpha-1 (IL4Ra1), dual oxidase 1 (DUOX1) and dual oxidase 2 (DUOX2). The protective effects of Selenium-L-methionine on radiation-induced histopathological damages and changes in the level of these cytokines and genes were detected.

METHODS

Four groups of 20 rats (5 rats in each) namely, control; Selenium-L-methionine, radiation and radiation plus Selenium-L-methionine were used in this study. 4 mg/kg of Selenium-Lmethionine was administered 1 day before irradiation and five consecutive days after irradiation. Irradiation was done using a dose of 15 Gy 60Co gamma rays at 109 cGy/min. All rats were sacrificed 10 weeks after irradiation for detecting changes in IL-4 and IL-13 cytokines, the expressions of IL13Ra2, IL4Ra1, Duox1 and Duox2 and histopathological changes.

RESULTS

The level of IL-4 but not IL-13 increased after irradiation. This was associated with increased expression of IL4Ra1, Duox1 and Duox2, in addition to changes in morphological properties. Selenium-L-methionine could attenuate all injury markers following lung irradiation.

CONCLUSION

Selenium-L-methionine can protect lung tissues against toxic effects of ionizing radiation. It is possible that the modulation of immune responses and redox interactions are involved in the radioprotective effect of this agent.

Radiation-induced myocardial fibrosis: Mechanisms underlying its pathogenesis and therapeutic strategies

Radiation-induced myocardial fibrosis (RIMF) is a potentially lethal clinical complication of chest radiotherapy (RT) and a final stage of radiation-induced heart disease (RIHD). RIMF is characterized by decreased ventricular elasticity and distensibility, which can result in decreased ejection fraction, heart failure and even sudden cardiac death. Together, these conditions impair the long-term health of post-RT survivors and limit the dose and intensity of RT required to effectively kill tumour cells. Although the exact mechanisms involving in RIMF are unclear, increasing evidence indicates that the occurrence of RIMF is related to various cells, regulatory molecules and cytokines. However, accurately diagnosing and identifying patients who may progress to RIMF has been challenging. Despite the urgent need for an effective treatment, there is currently no medical therapy for RIMF approved for routine clinical application. In this review, we investigated the underlying pathophysiology involved in the initiation and progression of RIMF before outlining potential preventative and therapeutic strategies to counter this toxicity.

Advances in research on the interaction between inflammation and cancer

Inflammation is the body's response to cell damage. Cancer is a general term that describes all malignant tumours. There are no confirmed data on cancer-related inflammation, but some research suggests that up to 50% of cancers may be linked to inflammation, which has led to the concept of ‘cancer-associated inflammation’. Although some cancer patients do not appear to have a chronic inflammatory background, there might be inflammatory cell infiltration in their cancer tissues. The continuation of the inflammatory response plays an important role in the initiation, promotion, malignant transformation, invasion and metastasis of cancer. Anti-inflammatory therapy has been shown to have some effects on the prevention and treatment of cancer, which supports a pathogenic relationship between inflammation and cancer. This review describes the interaction between inflammation and tumour development and the main mechanism of regulation of the inflammatory response during tumour development.

Melatonin Ameliorates Radiation-induced Sciatic Nerve Injury

Background:

Radiotherapy is a treatment method for cancer mostly utilized for about 60% of cancer patients. Peripheral neuropathy is one of the severe complications of radiotherapy. Two stages of neuropathy will occur following irradiation; electrophysiological and biochemical variations as the first stage, while the second stage involves fibrosis of soft tissues surrounding the exposed nerve. This novel study aimed to investigate the radioprotective effects of melatonin against ionizing radiation-induced sciatic nerve damage.

Methods:

60 rats were randomly assigned to four groups; C (Control), M (Melatonin), R (Radiation), MR (Radiation + Melatonin). Their right legs were exposed to 30 Gy single dose gamma rays. Melatonin (100 mg/kg) was administered 30 min before irradiation and once daily (5 mg/kg) till the day of rats’ sacrifice. Their exposed nerve tissues were evaluated for biochemical changes in addition to Electromyography (EMG) and Nerve Conduction Study (NCS).

Results:

4, 12 and 20 weeks post-irradiation, EMG and NCS examinations in R group showed reduced Compound Muscle Action Potential (CMAP) representing axonal degeneration when compared with C and M groups. Prolonged latency and a decrease in Conduction Velocity (CV) gave an indication of demyelinating neuropathy at 12 and 20 weeks. EMG and NCS results of R group showed partial nerve lesion. Biochemical assessments showed that irradiation of sciatic nerve led to increased MDA level, as well as decreased CAT and SOD activities. However, in all cases, treatment with melatonin can reverse these effects.

Conclusion:

We conclude that melatonin can improve electrophysiological, oxidative stress and antioxidant defense features of irradiated rats’ sciatic nerves. We would also recommend the use of melatonin in an optimal and safe dose. It should be administered over a long period of time for effective protection of the peripheral nerve tissues, as well as improving the therapeutic ratio of radiotherapy.

Radiation-Induced Normal Tissue Damage: Oxidative Stress and Epigenetic Mechanisms

Radiotherapy (RT) is currently one of the leading treatments for various cancers; however, it may cause damage to healthy tissue, with both short-term and long-term side effects. Severe radiation-induced normal tissue damage (RINTD) frequently has a significant influence on the progress of RT and the survival and prognosis of patients. The redox system has been shown to play an important role in the early and late effects of RINTD. Reactive oxygen species (ROS) and reactive nitrogen species (RNS) are the main sources of RINTD. The free radicals produced by irradiation can upregulate several enzymes including nicotinamide adenine dinucleotide phosphate oxidase (NADPH oxidase), lipoxygenases (LOXs), nitric oxide synthase (NOS), and cyclooxygenases (COXs). These enzymes are expressed in distinct ways in various cells, tissues, and organs and participate in the RINTD process through different regulatory mechanisms. In recent years, several studies have demonstrated that epigenetic modulators play an important role in the RINTD process. Epigenetic modifications primarily contain noncoding RNA regulation, histone modifications, and DNA methylation. In this article, we will review the role of oxidative stress and epigenetic mechanisms in radiation damage, and explore possible prophylactic and therapeutic strategies for RINTD.

The radioprotective effect of N-acetylcysteine against x-radiation-induced renal injury in rats

The purpose of this study was therefore to investigate the effects of radiotherapy on the kidney and the potential use of agents such as N-acetylcysteine (NAC) in developing a future therapeutic protocol for radiation-induced nephrotoxicity at the histopathological and biochemical levels. Our study consisted of three groups: control (oral saline solution only; group 1), irradiation (IR; group 2), and NAC + IR (group 3). The irradiation groups received a single dose of whole-body 6-Gy x-irradiation. The NAC group received 300 mg/kg by the oral route for 7 days, from 5 days before irradiation to 2 days after. All subjects were sacrificed under anesthesia 2 days after irradiation. IR increased tubular necrosis scores (TNS), MDA, and caspase-3 expression, while reducing renal tissue GSH levels. We also observed dilation in renal corpuscles and tubules. Capillary congestion was present in the intertubular spaces. NAC reduced the levels of TNS, MDA, and caspase-3 expression, but increased the levels of renal tissue GSH. ROS-scavenging antioxidants may represent a promising means of preventing renal injury in patients undergoing radiotherapy.

Fucoidan attenuates radioiodine-induced salivary gland dysfunction in mice

Background

Radioiodine (RI) treatments can destroy the cellular components of salivary glands (SG) and disrupt their function. This study investigated whether fucoidan could attenuate radioiodine-induced SG dysfunction in a mouse model.

Methods

Female C57BL/6 mice (n = 36) were classified into three groups; i) a normal (control) group, ii) an RI-treated group (0.2 mCi/20 g mouse, administered orally), and iii) a fucoidan and RI-treated group. Mice in each group were classified into three subgroups and sacrificed at 2, 4, and 12 weeks after RI treatment. The measurements of salivary flow rates and lag times and histomorphologic examinations were performed, and apoptotic assays were conducted. Changes in salivary ^99mTechnetium (Tc)-pertechnetate parameters using single-photon emission computed tomography were followed.

Results

Salivary flow rates and lag times in the fucoidan group were improved compared to the RI-treated group. Histologic examinations of SGs in the fucoidan group showed mucin-rich parenchymal areas and reduced periductal fibrosis as compared to the RI-treated group. Moreover, compared with the RI-treated group, fucoidan-treated groups showed evidence of cytoprotection, with a greater number of salivary epithelial cells and myoepithelial cells being observed. Fewer apoptotic cells were observed in the fucoidan group as compared to the RI group. The extent of ^99mTc pertechnetate excretion in the fucoidan group was similar to that of the control group.

Conclusion

Our results demonstrate that fucoidan administration before RI treatment could attenuate RI-induced SG damage and provides a possible candidate for preventing SG damage induced by RI.

Radiation-induced lung injury: latest molecular developments, therapeutic approaches, and clinical guidance

Cancer research has advanced throughout the years with respect to the personalization of the treatments and to targeting cancer-related molecular signatures on different organs. Still, the adverse events of the treatments such as radiotherapy are of high concern as they may increase the mortality rate due to their severity. With the improved efficiency of cancer treatments, patient survival has been increasing. Consequently, the number of patients with adverse effects from radiotherapy is also expected to increase in the forthcoming years. Therefore, approaches for personalized treatments include the elimination of adverse events and decreasing the toxicity in healthy tissues while increasing the efficiency of cancer cytotoxicity. In this context, this paper aims to discuss the recent advances in the field of thorax irradiation therapy and its related toxicities leading to radiation pneumonitis in cancer patients. Molecular mechanisms involved in the radiation-induced lung injury and approaches used to overcome this lung injury are discussed. The discourse covers approaches such as therapeutic administration of natural products, current and prospective radioprotective drugs, and applications of mesenchymal stem cells for radiation-induced lung injury.

Radioprotective effect of endogenous melatonin secretion associated with the circadian rhythm in irradiated rats

Purpose: We investigated the radioprotective effect of endogenous melatonin release at different times associated with the circadian rhythm on head and neck radiotherapy. Materials and methods: Two groups of animals were subjected daily to 8 Gy single fraction radiotherapy in the head and neck region from 5:00 to 6:00 (the morning group) or from 19:00 to 20:00 (the evening group). Corresponding untreated groups served as controls. Submandibular glands from rats sacrificed on the seventh day after irradiation were assessed biochemically and histopathologically. Melatonin, malondialdehyde and superoxide dismutase levels in blood collected immediately prior to irradiation were measured with rat-specific ELISA kits. Results: In irradiated rats, melatonin, malondialdehyde and superoxide dismutase levels were significantly higher in the evening group than in the morning group. In nonirradiated rats, melatonin and superoxide dismutase levels were significantly higher in the evening group than in the morning group. The areas of seromucous acinar cells were similar between the irradiated and nonirradiated evening groups, but the area was higher in the evening irradiated group than in the morning irradiated group. Conclusion: Consideration of endogenous melatonin secretion associated with the circadian rhythm may offer new therapeutic solutions for the complications of head and neck radiotherapy.

Radiation-Induced Heart Diseases: Protective Effects of Natural Products

Cardiovascular diseases (CVDs) account for the majority of deaths worldwide. Radiation-induced heart diseases (RIHD) is one of the side effects following exposure to ionizing radiation (IR). Exposure could be from various forms such as diagnostic imaging, radiotherapy for cancer treatment, as well as nuclear disasters and nuclear accidents. RIHD is mostly observed after radiotherapy for thoracic malignancies, especially left breast cancer. RIHD may affect the supply of blood to heart muscles, leading to an increase in the risk of heart attacks to irradiated persons. Due to its dose-limiting consequence, RIHD has a negative effect on the therapeutic efficacy of radiotherapy. Several methods have been proposed for protection against RIHD. In this paper, we review the use of natural products, which have shown promising results for protection against RIHD.

Gut microbiota: implications for radiotherapy response and radiotherapy-induced mucositis

Radiotherapy is a mainstay of solid tumor management but can be associated with unacceptable levels of off-target tissue toxicity which impact treatment outcomes and patients' quality of life. Tumour response to radiotherapy and the frequency and severity of radiotherapy-induced toxicities, especially mucositis, varies among patients. Gut microbiota has been found to modulate both the efficacy and toxicity of some types of cancer chemotherapies and immunotherapies but has yet to be investigated thoroughly in the setting of radiotherapy. Area covered: In this review, we discuss the potential role of gut microbiota on modulating radiotherapy-induced oral and gastrointestinal mucositis and the anti-tumor response to radiotherapy through modulation of immune responses. Expert opinion: The gut microbiota plays a major role in the modulation of systemic immune responses, which influence both radiotherapy response and gastrointestinal toxicities such as mucositis. Hence, investigating the gut microbiota link to the variation in radiotherapy responses and toxicities among patients is warranted. Future targeting of these responses with a patient-tailored restoration of optimal microbial composition could lead to a new era of mucositis prevention and enhanced tumor responses.

Changes in the Selected Antioxidant Defense Parameters in the Blood of Patients after High Resolution Computed Tomography

Ionizing radiation generated during high resolution computed tomography (HRCT) scanning may have an indirect effect on the mechanisms regulating the oxidative-antioxidant balance in the human body, which is one of the necessary factors ensuring the maintenance of its homeostasis. The aim of the study was to analyze the response of antioxidant systems through the determination of the antioxidant markers in the blood of patients exposed to oxidative stress resulting from the routine HRCT examination of the chest. Blood of 35 people aged 60.77 ± 10.81 taken before and at four time points after the examination constituted the test material. The determination of the total antioxidant capacity expressed as ferric reducing ability of plasma (FRAP) and ferric reducing antioxidant activity and ascorbic acid concentration (FRASC) were performed together with an examination of catalase activity and the concentration of the reduced glutathione. The organism’s response to ionizing radiation was associated with a significant decrease in the antioxidant markers’ levels at all time-points and showed a significant negative correlation depending on the radiation dose. Visible down-regulation of these markers is a response to increased oxidative stress. In light of the obtained results, the measurement of the selected markers of antioxidant defense may be a useful parameter of oxidative stress caused by ionizing radiation.

Estimation of radiation dose-reduction factor for cerium oxide nanoparticles in MRC-5 human lung fibroblastic cells and MCF-7 breast-cancer cells

In the current study, radiation dose-reduction factor (DRF) of nanoceria or cerium oxide nanoparticles (CONPs) in MRC-5 Human Lung Fibroblastic Cells and MCF-7 Breast-Cancer Cells was estimated. Characterization of CONPs was determined using scanner electron microscope (SEM), energy dispersive spectroscopy (EDS), transmission electron microscopy (TEM) and spectrophotometer. Then, six plans were designed with different radiation dose values on planning target value. The obtained MRC-5 and MCF-7 cells were treated with non-toxic concentrations of CONPs and then exposed. Finally, cell viability (%) of the cell lines was determined using MTT assay. The findings showed that CONPs have no significant radioprotective effect against 10 cGy radiation dose value. Nevertheless, 70 μM CONPs resulted in a significant radioprotection against 100, 200, 300, 400 and 500 cGy radiation dose values compared with the control group in MRC-5 cells. For all radiation dose values, mean cell viability (%) of MCF-7 had not increased significantly at the presence of nanoceria compared with control group. According to the findings, it was revealed that the use of CONPs have a significant radioprotective effect on normal lung cells, while they do not provide any protection for MCF-7 cancer cells. These properties can help to increase therapeutic ratio of radiotherapy.

Metformin Protects Against Radiation-Induced Heart Injury and Attenuates the Upregulation of Dual Oxidase Genes Following Rat's Chest Irradiation

Radiation-induced heart toxicity is one of the serious side effects after a radiation disaster or radiotherapy for patients with chest cancers, leading to a reduction in the quality of life of the patients. Evidence has shown that infiltration of inflammatory cells plays a key role in the development of functional damages to the heart via chronic upregulation of some pro-fibrotic and pro-inflammatory cytokines. These changes are associated with continuous free radical production and increased stiffness of heart muscle. IL-4 and IL-13 are two important pro-fibrotic cytokines which contribute to the side effects of ionizing radiation exposure. Recent studies have proposed that IL-4 through upregulation of DUOX2, and IL-13 via stimulation of DUOX1 gene expression, are involved in the development of radiation late effects. In the present study, we aimed to detect changes in the expression of these pathways following irradiation of rat’s heart. Furthermore, we evaluated the possible protective effect of metformin on the development of these abnormal changes. 20 male rats were divided into 4 groups (control, radiation, metformin treated, metformin + radiation). These rats were irradiated with 15 Gy ⁶⁰Co gamma rays, and sacrificed after 10 weeks for evaluation of the changes in the expression of IL4R1, IL-13R2a, DUOX1 and DUOX2. In addition, the levels of IL-4 and IL-13 cytokines, as well as infiltration of macrophages and lymphocytes were detected. Results showed an upregulation of both DUOX1 and DUOX2 pathways in the presence of metformin, while the level of IL-13 did not show any significant change. This was associated with infiltration of macrophages and lymphocytes. Also, treatment with metformin could significantly attenuate accumulation of inflammatory cells, and upregulate these pathways. Therefore, suppression of dual oxidase genes by metformin may be a contributory factor to its protective effect.

Curcumin as an anti-inflammatory agent: Implications to radiotherapy and chemotherapy

Cancer is the second cause of death worldwide. Chemotherapy and radiotherapy are the most common modalities for the treatment of cancer. Experimental studies have shown that inflammation plays a central role in tumor resistance and the incidence of several side effects following both chemotherapy and radiotherapy. Inflammation resulting from radiotherapy and chemotherapy is responsible for adverse events such as dermatitis, mucositis, pneumonitis, fibrosis, and bone marrow toxicity. Chronic inflammation may also lead to the development of second cancer during years after treatment. A number of anti-inflammatory drugs such as nonsteroidal anti-inflammatory agents have been proposed to alleviate chronic inflammatory reactions after radiotherapy or chemotherapy. Curcumin is a well-documented herbal anti-inflammatory agents. Studies have proposed that curcumin can help management of inflammation during and after radiotherapy and chemotherapy. Curcumin targets various inflammatory mediators such as cyclooxygenase-2, inducible nitric oxide synthase, and nuclear factor κB (NF-κB), thereby attenuating the release of proinflammatory and profibrotic cytokines, and suppressing chronic production of free radicals, which culminates in the amelioration of tissue toxicity. Through modulation of NF-κB and its downstream signaling cascade, curcumin can also reduce angiogenesis, tumor growth, and metastasis. Low toxicity of curcumin is linked to its cytoprotective effects in normal tissues. This protective action along with the capacity of this phytochemical to sensitize tumor cells to radiotherapy and chemotherapy makes it a potential candidate for use as an adjuvant in cancer therapy. There is also evidence from clinical trials suggesting the potential utility of curcumin for acute inflammatory reactions during radiotherapy such as dermatitis and mucositis.

Evaluating the Protective Effect of a Combination of Curcumin and Selenium-L-Methionine on Radiation Induced Dual Oxidase Upregulation

Background: Epidemiological studies have shown an increased incidence of heart diseases among survivors of Chernobyl disaster as well as Hiroshima and Nagasaki atomic bomb explosion. Similar results were observed for lung and left breast cancer patients. Experimental studies have proposed the chronic upregulation of some pro-inflammatory and pro-fibrotic cytokines. Recent studies have shown that upregulation of pro-oxidant enzymes play a key role in the development of late effects of ionizing radiation such as fibrosis. Interleukin-4 (IL-4) and Interleukin-13 (IL-13) are two important cytokines that have shown ability to induce production of free radicals through dual oxidases (Duox) i.e. Duox1 and Duox2. In this study, we aimed to detect the expression of IL-4 receptor-a1 (IL-4Ra1), IL-13 receptor-a2 (IL-13Ra2), Duox1 and Duox2 genes following irradiation of rat’s heart. In addition, we evaluated the possible role of the combination of curcumin and selenium-L-methionine on the regulation of these genes. Methods: Twenty rats were divided into 4 groups as follows; G1: control; G2: treatment with the combination of curcumin and selenium-L-methionine; G3: radiation; G4: radiation plus treatment with the combination of curcumin and selenium-L-methionine. Rats were sacrificed 10 weeks after irradiation for detecting the expression of IL-4Ra1, IL-13Ra2, Duox1 and Duox2. Results: Results showed that exposure to ionizing radiation caused upregulation of IL-4Ra1 by more than 4-fold as well as Duox1 and Duox2 by more than 5-fold. However, results showed no detectable expression for IL-13Ra2. Treatment with the combination of curcumin and selenium-L-methionine could attenuate the upregulation of all genes. Conclusion: This study has shown that exposing rat’s heart tissues to radiation leads to chronic upregulation of IL-4Ra1, Duox1 and Duox2 as well as pro-oxidant enzymes. Treatment with the combination of curcumin and selenium-L-methionine showed ability to attenuate the upregulation of these genes.