Transcription factors activated in mammalian cells after clinically relevant doses of ionizing radiation

Benzimidazole Derivative (N-{4-[2-(4-Methoxyphenyl)-1H-Benzimidazole-1-Sulfonyl] Phenyl} Acetamide) Ameliorates Methotrexate-Induced Intestinal Mucositis by Suppressing Oxidative Stress and Inflammatory Markers in Mice

Methotrexate (MTX)-induced intestinal mucositis (IM) is a common side effect in cancer treatment that impairs the immune system and gut microbes, resulting in loss of mucosal integrity and gut barrier dysfunction. The quality of life and outcomes of treatment are compromised by IM. The present study was designed to investigate the mucoprotective potential of the benzimidazole derivative N-{4-[2-(4-methoxyphenyl)-1H-benzimidazole-1-sulfonyl] phenyl} acetamide (B8) on MTX-induced IM in mice. IM was induced by a single dose of MTX in mice and assessed by physical manifestations as well as biochemical, oxidative, histological, and inflammatory parameters. B8 (1, 3, 9 mg/kg) significantly reduced diarrhea score, mitigated weight loss, increased feed intake and, survival rate in a dose-dependent manner. Notably, B8 exhibited a mucoprotective effect evident through the mitigation of villus atrophy, crypt hypoplasia, diminished crypt mitotic figures, mucin depletion, and oxidative stress markers (GSH, SOD, MDA, and catalase concentration). Gene expression analysis revealed that B8 downregulated the mRNA expression of tumor necrosis factor-α (TNF-α), cyclooxygenase-2 (COX-2), interleukin-6 (IL-6), IL-1β, and nuclear factor-κB (NF-κB) and concurrently upregulated IL-10 expression in contrast to the MTX group. Further, B8 significantly improved the luminal microflora profile by augmenting the growth of Lactobacillus spp. and reducing the number of pathogenic bacteria (E. coli). Additionally, the enzyme-linked immunoassay showed that B8 decreased the levels of pro-inflammatory cytokines. Our findings suggest that B8 had mucoprotective effects against MTX-induced IM and could be used as an adjunct in chemotherapy to deter this side effect.

A computational model of the DNA damage-induced IKK/ NF-κB pathway reveals a critical dependence on irradiation dose and PARP-1

The activation of IKK/NF-κB by genotoxic stress is a crucial process in the DNA damage response. Due to the anti-apoptotic impact of NF-κB, it can affect cell-fate decisions upon DNA damage and therefore interfere with tumor therapy-induced cell death. Here, we developed a dynamical model describing IKK/NF-κB signaling that faithfully reproduces quantitative time course data and enables a detailed analysis of pathway regulation. The approach elucidates a pathway topology with two hubs, where the first integrates signals from two DNA damage sensors and the second forms a coherent feedforward loop. The analyses reveal a critical role of the sensor protein PARP-1 in the pathway regulation. Introducing a method for calculating the impact of changes in individual components on pathway activity in a time-resolved manner, we show how irradiation dose influences pathway activation. Our results give a mechanistic understanding relevant for the interpretation of experimental and clinical studies.

Assessment of Oxidative Stress-Induced Oral Epithelial Toxicity

Reactive oxygen species (ROS) are highly reactive molecules generated in living organisms and an excessive production of ROS culminates in oxidative stress and cellular damage. Notably, oxidative stress plays a critical role in the pathogenesis of a number of oral mucosal diseases, including oral mucositis, which remains one of cancer treatments' most common side effects. We have shown previously that oral keratinocytes are remarkably sensitive to oxidative stress, and this may hinder the development and reproducibility of epithelial cell-based models of oral disease. Here, we examined the oxidative stress signatures that parallel oral toxicity by reproducing the initial events taking place during cancer treatment-induced oral mucositis. We used three oral epithelial cell lines (an immortalized normal human oral keratinocyte cell line, OKF6, and malignant oral keratinocytes, H357 and H400), as well as a mouse model of mucositis. The cells were subjected to increasing oxidative stress by incubation with hydrogen peroxide (H2O2) at concentrations of 100 μM up to 1200 μM, for up to 24 h, and ROS production and real-time kinetics of oxidative stress were investigated using fluorescent dye-based probes. Cell viability was assessed using a trypan blue exclusion assay, a fluorescence-based live-dead assay, and a fluorometric cytotoxicity assay (FCA), while morphological changes were analyzed by means of a phase-contrast inverted microscope. Static and dynamic real-time detection of the redox changes in keratinocytes showed a time-dependent increase of ROS production during oxidative stress-induced epithelial injury. The survival rates of oral epithelial cells were significantly affected after exposure to oxidative stress in a dose- and cell line-dependent manner. Values of TC50 of 800 μM, 800 μM, and 400 μM were reported for H400 cells (54.21 ± 9.04, p < 0.01), H357 cells (53.48 ± 4.01, p < 0.01), and OKF6 cells (48.64 ± 3.09, p < 0.01), respectively. Oxidative stress markers (MPO and MDA) were also significantly increased in oral tissues in our dual mouse model of chemotherapy-induced mucositis. In summary, we characterized and validated an oxidative stress model in human oral keratinocytes and identified optimal experimental conditions for the study of oxidative stress-induced oral epithelial toxicity.

High molecular weight hyaluronic acid drastically reduces chemotherapy-induced mucositis and apoptotic cell death

Oral and intestinal mucositis (OIM) are debilitating inflammatory diseases initiated by oxidative stress, resulting in epithelial cell death and are frequently observed in cancer patients undergoing chemo-radiotherapy. There are currently few preventative strategies for this debilitating condition. Therefore, the development of a safe and effective mucositis mitigating strategy is an unmet medical need. Hyaluronic acid (HA) preparations have been tentatively used in oral mucositis. However, the protective effects of HA in chemotherapy-induced mucositis and their underlying mechanisms remain to be fully elucidated. This study aimed to assess these mechanisms using multiple formulations of enriched HA (Mucosamin^®), cross-linked (xl-), and non-crosslinked high molecular weight HA (H-MW-HA) in an oxidative stress-induced model of human oral mucosal injury in vitro and an in vivo murine model of 5-flurouracil (5-FU)-induced oral/intestinal mucositis. All tested HA formulations protected against oxidative stress-induced damage in vitro without inducing cytotoxicity, with H-MW-HA also significantly reducing ROS production. Daily supplementation with H-MW-HA in vivo drastically reduced the severity of 5-FU-induced OIM, prevented apoptotic damage and reduced COX-2 enzyme activity in both the oral and intestinal epithelium. In 5-FU-injected mice, HA supplementation also significantly reduced serum levels of IL-6 and the chemokine CXCL1/KC, while the serum antioxidant activity of superoxide dismutase was elevated. Our data suggest that H-MW-HA attenuates 5-FU-induced OIM, at least partly, by impeding apoptosis, inhibiting of oxidative stress and suppressing inflammatory cytokines. This study supports the development of H-MW-HA preparations for preventing OIM in patients receiving chemotherapy.

Pathogenesis and therapy of radiation enteritis with gut microbiota

Radiotherapy is widely used in clinic due to its good effect for cancer treatment. But radiotherapy of malignant tumors in the abdomen and pelvis is easy to cause radiation enteritis complications. Gastrointestinal tract contains numerous microbes, most of which are mutualistic relationship with the host. Abdominal radiation results in gut microbiota dysbiosis. Microbial therapy can directly target gut microbiota to reverse microbiota dysbiosis, hence relieving intestinal inflammation. In this review, we mainly summarized pathogenesis and novel therapy of the radiation-induced intestinal injury with gut microbiota dysbiosis and envision the opportunities and challenges of radiation enteritis therapy.

Exposure to ionizing radiations and changes in blood cells and interleukin-6 in radiation workers

Long-term exposure to ionizing radiation (IR) can cause dire health consequences even less than the dose limits. Previous biomonitoring studies have focused more on complete blood counts (CBCs), with non-coherent results. In this study, we aimed to investigate the association between exposure to IR and cytokine interleukin-6 (IL-6) along with hematological parameters in Tabriz megacity's radiation workers. In this hospital-based study, blood samples were taken from 33 radiation workers (exposed group) and 34 non-radiation workers (control group) in 4 hospitals. Absorbed radiation dose was measured by a personal film badge dosimeter in radiation workers. The studied biomarkers and all of the selected covariates were measured and analyzed using adjusted multiple linear regression models. The exposed doses for all radiation workers were under the dose limits (overall mean = 1.18 mSv/year). However, there was a significant association between exposure to ionizing radiation and IL-6 (49.78 vs 36.17; t = 2.4; p = 0.02) and eosinophils (0.17 vs 0.14; t = 2.02; p = 0.049). The difference between the mean of the other biomarkers in radiation workers was not statistically significant compared to the control group. This study demonstrated that long-term exposure to ionizing radiation, even under the dose limits, is related to a significantly increased level of some blood biomarkers (Il-6 and eosinophil) that, in turn, can cause subsequent health effects such as cancer.

Activating transcription factor 3 inhibits NF‑κB p65 signaling pathway and mediates apoptosis and cell cycle arrest in cervical cancer cells

BACKGROUND

As a novel tumor suppressor mediator, activating transcription factor 3 (ATF3) has recently aroused an interest in its possible therapeutic applications in various cancers. In this study, we evaluated the effect of ATF3 overexpression on the cellular level of nuclear factor kappa B (NF-κB) in human papillomavirus (HPV)-infected Ca Ski cells. Further, we examined whether ATF3 could mediate cell cycle arrest and alter the apoptosis level of Ca Ski cells.

METHODS

The biological behavior of Ca Ski cells was evaluated prior and subsequent to the overexpression of ATF3 by MTT assay, fluorescence microscopy, cell cycle and annexin V/PI flow cytometric analysis. The effect of ectopic ATF3 expression on the cellular level of NF-κB in HPV-positive cells was evaluated by western blotting assay.

RESULTS

The overexpression of ATF3 in Ca Ski cells led to significant apoptosis and cell cycle arrest in the G1 phase. Western blotting assay revealed a discernible reduction of NF-κB p65 level in cervical cancer cells.

CONCLUSION

ATF3 acts as a tumor suppressor factor in HPV16-infected Ca Ski cells and exerts anti-cancer effects on HPV16-related cervical cancer cells potentially by hindering cell growth and inducing cell cycle arrest through the down-regulation of NF-κB. Our results suggest that ATF3 induction or NF-κB suppression may be useful targets for HPV16-related cervical cancer prevention and treatment.

Radiation in Gastroenterology

The benefit of radiation is immense in the field of gastroenterology. Radiation is used daily in different gastrointestinal imaging and diagnostic and therapeutic interventional procedures. Radiotherapy is one of the primary modalities of treatment of gastrointestinal malignancies. There are various modalities of radiotherapy. Radiotherapy can injure malignant cells by directly damaging DNA, RNA, proteins, and lipids and indirectly by forming free radicals. External beam radiation, internal beam radiation and radio-isotope therapy are the major ways of delivering radiation to the malignant tissue. Radiation can also cause inflammation, fibrosis, organ dysfunction, and malignancy. Patients with repeated exposure to radiation for diagnostic imaging and therapeutic procedures are at slightly increased risk of malignancy. Gastrointestinal endoscopists performing fluoroscopy-guided procedures are also at increased risk of malignancy and cataract formation. The radiological protection society recommends certain preventive and protective measures to avoid side effects of radiation. Gastrointestinal complications related to radiation therapy for oncologic processes, and exposure risks for patients and health care providers involved in diagnostic or therapeutic imaging will be discussed in this review.

Translational Implications for Radiosensitizing Strategies in Rhabdomyosarcoma

Rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma of childhood and adolescence that includes FP-RMS, harboring the fusion oncoprotein PAX3/7-FOXO1 and FN-RMS, often mutant in the RAS pathway. Risk stratifications of RMS patients determine different prognostic groups and related therapeutic treatment. Current multimodal therapeutic strategies involve surgery, chemotherapy (CHT) and radiotherapy (RT), but despite the deeper knowledge of response mechanisms underpinning CHT treatment and the technological improvements that characterize RT, local failures and recurrence frequently occur. This review sums up the RMS classification and the management of RMS patients, with special attention to RT treatment and possible radiosensitizing strategies for RMS tumors. Indeed, RMS radioresistance is a clinical problem and further studies aimed at dissecting radioresistant molecular mechanisms are needed to identify specific targets to hit, thus improving RT-induced cytotoxicity.

Modulation of diverse oncogenic signaling pathways by oroxylin A: An important strategy for both cancer prevention and treatment

BACKGROUND

Regardless of major advances in diagnosis, prevention and treatment strategies, cancer is still a foreboding cause due to factors like chemoresistance, radioresistance, adverse side effects and cancer recurrence. Therefore, continuous development of unconventional approaches is a prerequisite to overcome foregoing glitches. Natural products have found their way into treatment of serious health conditions, including cancer since ancient times. The compound oroxylin A (OA) is one among those with enormous potential against different malignancies. It is a flavonoid obtained from the several plants such as Oroxylum indicum, Scutellaria baicalensis and S. lateriflora, Anchietea pyrifolia, and Aster himalaicus.

PURPOSE

The main purpose of this study is to comprehensively elucidate the anticancerous effects of OA against various malignancies and unravel their chemosensitization and radiosensitization potential. Pharmacokinetic and pharmacodynamic studies of OA have also been investigated.

METHOD

The literature on antineoplastic effects of OA was searched in PubMed and Scopus, including in vitro and in vivo studies and is summarized based on a systematic review protocol prepared according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The term "oroxylin A" was used in combination with "cancer" and all the title, abstracts and keywords appeared were considered.

RESULTS

In Scopus, a total of 157 articles appeared out of which 103 articles that did not meet the eligibility criteria were eliminated and 54 were critically evaluated. In PubMed, from the 85 results obtained, 26 articles were eliminated and 59 were included in the preparation of this review. Mounting number of studies have illustrated the anticancer effects of OA, and its mechanism of action.

CONCLUSION

OA is a promising natural flavonoid possessing wide range of pleiotropic properties and is a potential anticancer agent. It has a great potential in the treatment of multiple cancers including brain, breast, cervical, colon, esophageal, gall bladder, gastric, hematological, liver, lung, oral, ovarian, pancreatic and skin. However, lack of pharmacokinetic studies, toxicity assessments, and dose standardization studies and adverse effects limit the optimization of this compound as a therapeutic agent.

The importance of hypoxia in radiotherapy for the immune response, metastatic potential and FLASH-RT

PURPOSE

Hypoxia (low oxygen) is a common feature of solid tumors that has been intensely studied for more than six decades. Here we review the importance of hypoxia to radiotherapy with a particular focus on the contribution of hypoxia to immune responses, metastatic potential and FLASH radiotherapy, active areas of research by leading women in the field.

CONCLUSION

Although hypoxia-driven metastasis and immunosuppression can negatively impact clinical outcome, understanding these processes can also provide tumor-specific vulnerabilities that may be therapeutically exploited. The different oxygen tensions present in tumors and normal tissues may underpin the beneficial FLASH sparing effect seen in normal tissue and represents a perfect example of advances in the field that can leverage tumor hypoxia to improve future radiotherapy treatments.

Exploring subcellular responses of prostate cancer cells to clinical doses of X-rays by Raman microspectroscopy

Modern techniques of radiotherapy such as fractioned radiotherapy require applications of low doses of ionizing radiation (up to 10 Gy) for effective patient treatment. It is, therefore, crucial to understand the response mechanisms in cancer cells irradiated with low (clinical) doses. The cell's response to irradiation depends on a dose and post-irradiation time. Both factors should be considered when studying the influence of ionizing radiation on cancer cells. Thus, in the present study, PC-3 prostate cancer cells were irradiated with clinical doses of X-rays to determine dose- and time-dependent response to the irradiation. Raman spectroscopy and biological methods (MTT and comet assays) were applied for the analysis of biochemical changes in the cells induced by low doses of X-ray irradiation at 0 h and 24 h post-irradiation timepoints. Due to a limited view of the biochemical changes at the subcellular level given by single spectrum Raman measurements, Raman mapping of the whole cell area was performed. The results were compared with those obtained for cell irradiation with high doses. The analysis was based on the Partial Least Squares Regression (PLSR) method for the cytoplasmic and nuclear regions separately. Additionally, for the first time, irradiation classification was performed to confirm Raman spectroscopy as a powerful tool for studies on cancer cells treated with clinical doses of ionizing radiation.

Metabolic Rewiring in Radiation Oncology Toward Improving the Therapeutic Ratio

To meet the anabolic demands of the proliferative potential of tumor cells, malignant cells tend to rewire their metabolic pathways. Although different types of malignant cells share this phenomenon, there is a large intracellular variability how these metabolic patterns are altered. Fortunately, differences in metabolic patterns between normal tissue and malignant cells can be exploited to increase the therapeutic ratio. Modulation of cellular metabolism to improve treatment outcome is an emerging field proposing a variety of promising strategies in primary tumor and metastatic lesion treatment. These strategies, capable of either sensitizing or protecting tissues, target either tumor or normal tissue and are often focused on modulating of tissue oxygenation, hypoxia-inducible factor (HIF) stabilization, glucose metabolism, mitochondrial function and the redox balance. Several compounds or therapies are still in under (pre-)clinical development, while others are already used in clinical practice. Here, we describe different strategies from bench to bedside to optimize the therapeutic ratio through modulation of the cellular metabolism. This review gives an overview of the current state on development and the mechanism of action of modulators affecting cellular metabolism with the aim to improve the radiotherapy response on tumors or to protect the normal tissue and therefore contribute to an improved therapeutic ratio.

Status of Treatment and Prophylaxis for Radiation-Induced Oral Mucositis in Patients With Head and Neck Cancer

Radiation-induced oral mucositis (RIOM) is one of the most frequent complications in head and neck cancer (HNC) patients undergoing radiotherapy (RT). It is a type of mucosal injury associated with severe pain, dysphagia, and other symptoms, which leads to the interruption of RT and other treatments. Factors affecting RIOM include individual characteristics of HNC patients, concurrent chemoradiation therapy, and RT regimen, among others. The pathogenesis of RIOM is not yet fully understood; however, the release of inflammatory transmitters plays an important role in the occurrence and development of RIOM. The five biological stages, including initiation, primary damage response, signal amplification, ulceration, and healing, are widely used to describe the pathophysiology of RIOM. Moreover, RIOM has a dismal outcome with limited treatment options. This review will discuss the epidemiology, pathogenesis, clinical appearance, symptomatic treatments, and preventive measures related to this disease. We hope to provide a reference for the clinical treatment and prevention of RIOM in HNC patients after RT.

A nuclear factor kappa B reporter cell line used to evaluate ex vivo the net inflammatory effect of plasma samples from patients with rheumatoid arthritis, psoriasis, or COVID-19

BACKGROUND

The overall clinical outcome of inflammatory conditions is the result of the balance between pro-inflammatory and anti-inflammatory mediators. Because nuclear factor kappa B (NF-ĸB) is at the bottom of many inflammatory conditions, methods to evaluate the net effect of inflammation modulators on this master regulator have been conceptualized for years.

METHODS

Using an ex vivo NF-ĸB reporter cell line-based assay, plasma samples of patients with rheumatoid arthritis (n = 27), psoriasis (n = 15), or severe coronavirus disease-19 (COVID-19) (n = 21) were investigated for NF-ĸB activation compared to plasma samples from 9 healthy volunteers.

RESULTS

When separated by C-reactive protein (CRP) threshold levels, samples of patients exhibiting increased CRP levels (≥5 mg/l) activated NF-ĸB more efficiently than samples from patients with levels below 5 mg/l (P = 0.0001) or healthy controls (P = 0.04). Overall, there was a moderate association of CRP levels with NF-ĸB activation (Spearman r = 0.66; p < 0.0001). Plasma from COVID-19 patients activated NF-ĸB more efficiently (mean 2.4-fold compared to untreated reporter cells) than samples from any other condition (healthy controls, 1.8-fold, P = 0.0025; rheumatoid arthritis, 1.7-fold, P < 0.0001; psoriasis, 1.7-fold, P < 0.0001). In contrast, effects of rheumatoid arthritis, psoriasis, or healthy volunteer samples did not differ.

CONCLUSION

This study shows that a NF-ĸB reporter cell line can be used to evaluate the net inflammatory effect of clinical plasma samples. Patients with chronic but stable rheumatoid arthritis or psoriasis do not exhibit increased plasma levels of NF-ĸB-activating compounds as opposed to COVID-19 patients with high inflammatory burden.

Physicochemical damage and early-stage biological response to X-ray radiation studied in prostate cancer cells by Raman spectroscopy

Exposure to ionizing radiation significantly affects biochemistry of cancer cells. The effect of irradiation can be divided into two stages, that is, the physicochemical stage and the biological response. Both effects induce different biochemical changes in the cells and should be analyzed as two separate phenomena. Thus, in the current study, Raman spectroscopy of prostate cancer cells fixed before (the physicochemical damage model) and just after (the biological response model) irradiation was undertaken to compare biochemical composition of irradiated cancer cells at both stages. Spectroscopic analysis of the cells was performed separately for cytoplasmic and nuclear regions. Biochemical changes of irradiated cells were analyzed using partial least squares regression (PLSR) method on the basis of the collected Raman spectra. Regression coefficients were therefore used to describe differences and similarities between biochemical composition of cancer cells undergoing the physicochemical stage and biological response. Additionally, PLSR models of both phenomena were compared for linear dose-dependence and a cross prediction.

Lysosomal trafficking mediated by Arl8b and BORC promotes invasion of cancer cells that survive radiation

Enhanced invasiveness, a critical determinant of metastasis and poor prognosis, has been observed in cancer cells that survive cancer therapy, including radiotherapy. Here, we show that invasiveness in radiation-surviving cancer cells is associated with alterations in lysosomal exocytosis caused by the enhanced activation of Arl8b, a small GTPase that regulates lysosomal trafficking. The binding of Arl8b with its effector, SKIP, is increased after radiation through regulation of BORC-subunits. Knockdown of Arl8b or BORC-subunits decreases lysosomal exocytosis and the invasiveness of radiation-surviving cells. Notably, high expression of ARL8B and BORC-subunit genes is significantly correlated with poor prognosis in breast cancer patients. Sp1, an ATM-regulated transcription factor, is found to increase BORC-subunit genes expression after radiation. In vivo experiments show that ablation of Arl8b decreases IR-induced invasive tumor growth and distant metastasis. These findings suggest that BORC-Arl8b-mediated lysosomal trafficking is a target for improving radiotherapy by inhibiting invasive tumor growth and metastasis.

Dynamic differences between DNA damage repair responses in primary tumors and cell lines

The study of DNA damage repair response (DDR) in prostate cancer is restricted by the limited number of prostate cancer cell lines and lack of surrogates for heterogeneity in clinical samples. Here, we sought to leverage our experience with patient derived explants (PDEs) cultured ex vivo to study dynamics of DDR in primary tumors following application of clinically relevant doses of ionizing radiation (IR) to tumor cells in their native 3-dimensional microenvironment. We compared DDR dynamics between prostate cancer cell lines, PDEs and xenograft derived explants (XDEs) following treatment with IR (2Gy) either alone or in combination with pharmacological modulators of DDR. We have shown that following treatment with 2Gy, DDR can be consistently detected in PDEs from multiple solid tumors, including prostate, kidney, testes, lung and breast, as evidenced by γ-H2AX, 53BP1, phospho-ATM and phospho-DNA-PKcs foci. By examining kinetics of resolution of IR-induced foci, we have shown that DDR in prostate PDEs (complete resolution in 8 h) is much faster than in prostate cancer cell lines (<50% resolution in 8 h). The transcriptional profile of DDR genes following 2Gy IR appears to be distinct between PDEs and cell lines. Pre-treatment with drugs targeting DDR pathways differentially alter the kinetics of DDR in the PDEs and cell lines, as evidenced by altered kinetics of foci resolution. This study highlights the utility of PDEs as a robust model system for short-term evaluation of DDR in primary solid tumors in clinically relevant microenvironment.

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IR induces distinct DNA damage repair kinetics in prostate cancer PDEs and cell lines.

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IR induces a distinct transcriptional program in prostate cancer PDE and cell lines.

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DNA-PKcs inhibition blocks IR-induced DDR in prostate cancer PDE.

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Inhibition of AR impairs NHEJ in prostate cancer PDEs.

RIP1 Is a Novel Component of γ-ionizing Radiation-Induced Invasion of Non-Small Cell Lung Cancer Cells

Abstract: Previously, we demonstrated that γ-ionizing radiation (IR) triggers the invasion/migration of A549 cells via activation of an EGFR-p38/ERK-STAT3/CREB-1-EMT pathway. Here, we have demonstrated the involvement of a novel intracellular signaling mechanism in γ-ionizing radiation (IR)-induced migration/invasion. Expression of receptor-interacting protein (RIP) 1 was initially increased upon exposure of A549, a non-small cell lung cancer (NSCLC) cell line, to IR. IR-induced RIP1 is located downstream of EGFR and involved in the expression/activity of matrix metalloproteases (MMP-2 and MMP-9) and vimentin, suggesting a role in epithelial-mesenchymal transition (EMT). Our experiments showed that IR-induced RIP1 sequentially induces Src-STAT3-EMT to promote invasion/migration. Inhibition of RIP1 kinase activity and expression blocked induction of EMT by IR and suppressed the levels and activities of MMP-2, MMP-9 and vimentin. IR-induced RIP1 activation was additionally associated with stimulation of the transcriptional factor NF-κB. Specifically, exposure to IR triggered NF-κB activation and inhibition of NF-κB suppressed IR-induced RIP1 expression, followed by a decrease in invasion/migration as well as EMT. Based on the collective results, we propose that IR concomitantly activates EGFR and NF-κB and subsequently triggers the RIP1-Src/STAT3-EMT pathway, ultimately promoting metastasis.

Efficacy of Aloe-Vera Use for Prevention of Chemotherapy-Induced Oral Mucositis in Children with Acute Lymphoblastic Leukemia: A Randomized Controlled Clinical Trial

Oral mucositis can be caused by chemotherapy and can affect a patient's quality of life. Nowadays, to prevent chemotherapy-induced oral mucositis (CIOM) is a crucial point in palliative care centers. This trial aimed to assess the effectiveness of aloe-vera in that concept. The trial was accomplished at Hematology Department of Hospital of Children of Damascus University, Syria. Acute lymphoblastic leukemia (ALL) children were the population from which 26 children were enrolled in the study. They were aged between 3 and 6 years old and were randomly referred according to the intervention into two groups, Aloe-vera (AV) and sodium bicarbonate 5% (13 each). Spongeous sticks were used to help in applying the material on tongue, labial and buccal mucosa, lips, floor of the mouth, and hard palate. Two blinded external examiners evaluated oral mucosa weekly for up to 2 months using the World Health Organization grading scale. Mann-Whitney U test was used to analyze data. According to the observed findings, CIOM degrees were less severe in the aloe-vera group than in the sodium bicarbonate group. Statistically significant difference of occurrence of different CIOM degrees between groups was recorded in the 2nd, 3rd, 4th, and 7th weeks of follow-up period. Moreover, Mann-Whitney U test indicated that patients in the sodium bicarbonate group began CIOM sooner than those in the aloe-vera group with a statistically significant difference (p = .001). These findings show that topical application of aloe-vera solution is effective in the prevention of CIOM in ALL children.

The role of radiation induced oxidative stress as a regulator of radio-adaptive responses

Purpose: Various sources of radiation including radiofrequency, electromagnetic radiation (EMR), low- dose X-radiation, low-level microwave radiation and ionizing radiation (IR) are indispensable parts of modern life. In the current review, we discussed the adaptive responses of biological systems to radiation with a focus on the impacts of radiation-induced oxidative stress (RIOS) and its molecular downstream signaling pathways.Materials and methods: A comprehensive search was conducted in Web of Sciences, PubMed, Scopus, Google Scholar, Embase, and Cochrane Library. Keywords included Mesh terms of "radiation," "electromagnetic radiation," "adaptive immunity," "oxidative stress," and "immune checkpoints." Manuscripts published up until December 2019 were included.Results: RIOS induces various molecular adaptors connected with adaptive responses in radiation exposed cells. One of these adaptors includes p53 which promotes various cellular signaling pathways. RIOS also activates the intrinsic apoptotic pathway by depolarization of the mitochondrial membrane potential and activating the caspase apoptotic cascade. RIOS is also involved in radiation-induced proliferative responses through interaction with mitogen-activated protein kinases (MAPks) including p38 MAPK, ERK, and c-Jun N-terminal kinase (JNK). Protein kinase B (Akt)/phosphoinositide 3-kinase (PI3K) signaling pathway has also been reported to be involved in RIOS-induced proliferative responses. Furthermore, RIOS promotes genetic instability by introducing DNA structural and epigenetic alterations, as well as attenuating DNA repair mechanisms. Inflammatory transcription factors including macrophage migration inhibitory factor (MIF), nuclear factor κB (NF-κB), and signal transducer and activator of transcription-3 (STAT-3) paly major role in RIOS-induced inflammation.Conclusion: In conclusion, RIOS considerably contributes to radiation induced adaptive responses. Other possible molecular adaptors modulating RIOS-induced responses are yet to be divulged in future studies.

Upregulation of CD73 Confers Acquired Radioresistance and is Required for Maintaining Irradiation-selected Pancreatic Cancer Cells in a Mesenchymal State

The molecular mechanisms underlying exceptional radioresistance in pancreatic cancer remain elusive. In the present study, we established a stable radioresistant pancreatic cancer cell line MIA PaCa-2-R by exposing the parental MIA PaCa-2 cells to fractionated ionizing radiation (IR). Systematic proteomics and bioinformatics analysis of protein expression in MIA PaCa-2 and MIA PaCa-2-R cells revealed that several growth factor-/cytokine-mediated pathways, including the OSM/STAT3, PI3K/AKT, and MAPK/ERK pathways, were activated in the radioresistant cells, leading to inhibition of apoptosis and increased epithelial-mesenchymal plasticity. In addition, the radioresistant cells exhibited enhanced capabilities of DNA repair and antioxidant defense compared with the parental cells. We focused functional analysis on one of the most up-regulated proteins in the radioresistant cells, ecto-5'-nucleotidase (CD73), which is a cell surface protein that is overexpressed in different types of cancer. Ectopic overexpression of CD73 in the parental cells resulted in radioresistance and conferred resistance to IR-induced apoptosis. Knockdown of CD73 re-sensitized the radioresistant cells to IR and IR-induced apoptosis. The effect of CD73 on radioresistance and apoptosis is independent of the enzymatic activity of CD73. Further studies demonstrate that CD73 up-regulation promotes Ser-136 phosphorylation of the proapoptotic protein BAD and is required for maintaining the radioresistant cells in a mesenchymal state. Our findings suggest that expression alterations in the IR-selected pancreatic cancer cells result in hyperactivation of the growth factor/cytokine signaling that promotes epithelial-mesenchymal plasticity and enhancement of DNA repair. Our results also suggest that CD73, potentially a novel downstream factor of the enhanced growth factor/cytokine signaling, confers acquired radioresistance by inactivating proapoptotic protein BAD via phosphorylation of BAD at Ser-136 and by maintaining the radioresistant pancreatic cancer cells in a mesenchymal state.

Is pain part of a systemic syndrome in head and neck cancer?

Head and neck cancers (HNC) represent 5% of all malignancies worldwide with about 180,000 cancer deaths per year. Patients with HNC are characterized by a systemic inflammatory state, generally associated with worse outcomes. Treatment-related toxicity is common among HNC patients and causes systemic consequences such as fatigue or cognitive dysfunction. The therapeutic treatments of HNC involve the release in circulation of inflammatory systemic mediators, whose effects trigger a vicious circle that may lead to functional and behavioral alterations. The areas of the head and neck are highly sensitive to pain. Literature data confirm that in HNC patients, pain is one of the most distressing symptoms across all the phases of treatment. Pain is associated with worse general conditions, depression, fatigue, impaired cognitive functions, and lower survival rate. The treatment of advanced HNC cases is multimodal and requires a multidisciplinary psycho-socio-pharmacological approach mediated by a team of experts. The pharmacological approach in management of HNC patients with pain is fundamental and involves the use of opioids, NSAIDs, steroids, or other drugs. Opioids in pain management therapy in patients with HNC could allow the pain level to be adequately monitored, thus improving quality of life. The integration of opioid and non-opioid therapy as well as non-pharmacological interventions is essential for the rehabilitation of physical, social, and psychological functions and to achieve pain control in patients with HNC. Opioid treatment is the mainstay for pain control, being used both for background and breakthrough cancer pain (BTcP) episodes. Fentanyl, easily absorbed and generally well tolerated, appears to be a possible choice due to its versatility. Non-pharmacological interventions, such as tailored yoga, physical exercise, and acupuncture, may have a role in pain management in patients with HNC.

Search and Selection of Probiotics That Improve Mucositis Symptoms in Oncologic Patients. A Systematic Review

Mucositis is a common and severe adverse effect of radiotherapy and/or chemotherapy treatments applied to oncologic patients. The development of effective therapies and adjuvant treatments to increase their efficacy and reduce adverse effect is a priority in cancer therapy. Probiotics are non-pathogenic live microorganisms that when ingested in adequate amounts can colonize the intestinal tract promoting the restoration of a healthy gut microbiota and contributing to all its functions including the maintenance of the integrity of the mucosa and the modulation of the immune system. In order to check the possible efficacy and safety of these microorganisms to prevent or ameliorate mucositis' symptoms, we have systematically searched the bibliographic databases MEDLINE (via Pubmed), EMBASE, The Cochrane library, Scopus, Web of science, and Latin American and Caribbean Literature in Health of Sciences (LILACS) using the descriptors "Mucositis", "Probiotics", "Neoplasms", "Humans", and "Clinical Trials". After applying our inclusion and exclusion criteria, 15 studies were accepted for review and critical analysis. Our analysis suggests that a combination of Bifidobacterium longum, Lactobacillus acidophilus, Bifidobacterium breve, Bifidobacterium infantis, and Saccharomyces boulardii could be a good combination of probiotics to reduce incident rates of mucositis or ameliorate its symptoms in chemo or radiotherapy treated patients.

High-throughput transcriptome sequencing reveals extremely high doses of ionizing radiation-response genes in Caenorhabditis elegans

This study sought novel ionizing radiation-response (IR-response) genes in Caenorhabditis elegans (C. elegans). C. elegans was divided into three groups and exposed to different high doses of IR: 0 gray (Gy), 200 Gy, and 400 Gy. Total RNA was extracted from each group and sequenced. When the transcriptomes were compared among these groups, many genes were shown to be differentially expressed, and these genes were significantly enriched in IR-related biological processes and pathways, including gene ontology (GO) terms related to cellular behaviours, cellular growth and purine metabolism and kyoto encyclopedia of genes and genomes (KEGG) pathways related to ATP binding, GTPase regulator activity, and RNA degradation. Quantitative reverse-transcription PCR (qRT-PCR) confirmed that these genes displayed differential expression across the treatments. Further gene network analysis showed a cluster of novel gene families, such as the guanylate cyclase (GCY), Sm-like protein (LSM), diacylglycerol kinase (DGK), skp1-related protein (SKR), and glutathione S-transferase (GST) gene families which were upregulated. Thus, these genes likely play important roles in IR response. Meanwhile, some important genes that are well known to be involved in key signalling pathways, such as phosphoinositide-specific phospholipase C-3 (PLC-3), phosphatidylinositol 3-kinase age-1 (AGE-1), Raf homolog serine/threonine-protein kinase (LIN-45) and protein cbp-1 (CBP-1), also showed differential expression during IR response, suggesting that IR response might perturb these key signalling pathways. Our study revealed a series of novel IR-response genes in Caenorhabditis elegans that might act as regulators of IR response and represent promising markers of IR exposure.

Sp1 contributes to radioresistance of cervical cancer through targeting G2/M cell cycle checkpoint CDK1

Background/aims

Radioresistance remains a significant obstacle in the therapy of cervical cancer, and the mechanism of it is still unclear. We aimed to investigate the role of specificity protein 1 (Sp1) in radioresistance of cervical cancer.

Methods

Sp1 was examined immunohistochemically on tissues from 36 human cervical cancer patients. We used RT-qPCR and Western blot to examine the expression of Sp1 in irradiated cervical cancer cell lines SiHa and HeLa. The role of Sp1 in radioresistance of cervical cancer cells was assessed by colony-formation assay and cell cycle analysis. Dual-luciferase reporter assay was performed to detect the downstream of Sp1.

Results

High Sp1 expression was positively correlated with advanced International Federation of Gynecology and Obstetrics (FIGO) stage, lymph node metastasis, and lymphovascular space invasion (LVSI) of cervical cancer. The expression of Sp1 was dose-dependently increased in irradiated cervical cancer cell lines at both mRNA and protein levels. Colony-formation assay showed that alteration of Sp1 expression affected the survival of cervical cancer cells with radiotherapy (RT) treatment. Knockdown of Sp1 significantly strengthened the cellular response to radiation by inducing G2/M arrest in cervical cancer cells. Overexpression of Sp1 significantly decreased G2/M arrest in cervical cancer cells, which was related to upregulation of CDK1 expression. Dual-luciferase reporter assay showed the direct effect of Sp1 on the transcriptional activation of CDK1.

Conclusion

Sp1 may contribute to radioresistance through inhibiting G2/M phase arrest by targeting CDK1, and be considered as a potential therapeutic target to promote the effect of RT for patients with cervical cancer.

Simultaneous Inhibition of EGFR and HER2 via Afatinib Augments the Radiosensitivity of Nasopharyngeal Carcinoma Cells

Ionizing radiation (IR) is the central component of the therapeutic scheme for nasopharyngeal carcinoma (NPC) at present. Previous studies show that inhibition of epidermal growth factor receptor (EGFR) enhances the radiosensitivity of NPC; however the effects of EGFR-targeted agents are limited. In this study, we observed that simultaneously inhibition of EGFR and HER2 by afatinib could augment the radiosensitivity of NPC cells; this approach has an advantage over erlotinib-mediated inhibition of EGFR alone. The afatinib-induced augmentation of NPC cell radiosensitivity was associated with increases in apoptosis and accumulation of DNA damage that were induced by radiation. In addition, the crosstalk between radiation-induced activities and EGFR-, and HER2-related downstream pathways may contribute to the enhancement of radiosensitivity. Our findings indicate the potential of repositioning afatinib or other ERBB-family-targeted agents for improving radiation response in NPC cells.

Establishment and characterization of a radiation-induced dermatitis rat model

Radiation‐induced dermatitis is a common and serious side effect after radiotherapy. Current clinical treatments cannot efficiently or fully prevent the occurrence of post‐irradiation dermatitis, which remains a significant clinical problem. Resolving this challenge requires gaining a better understanding of the precise pathophysiology, which in turn requires establishment of a suitable animal model that mimics the clinical condition, and can also be used to investigate the mechanism and explore effective treatment options. In this study, a single dose of 90 Gy irradiation to rats resulted in ulceration, dermal thickening, inflammation, hair follicle loss, and sebaceous glands loss, indicating successful establishment of the model. Few hair follicle cells migrated to form epidermal cells, and both the severity of skin fibrosis and hydroxyproline levels increased with time post‐irradiation. Radiation damaged the mitochondria and induced both apoptosis and autophagy of the skin cells. Therefore, irradiation of 90 Gy can be used to successfully establish a rat model of radiation‐induced dermatitis. This model will be helpful for developing new treatments and gaining a better understanding of the pathological mechanism of radiation‐induced dermatitis. Specifically, our results suggest autophagy regulation as a potentially effective therapeutic target.

Role of NF-κB activation in mouse bone marrow stromal cells exposed to 900-MHz radiofrequency fields (RF)

Nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) is a primary transcription factor which plays a key role in several cellular processes including proliferation and survival. It is well known that exposure to non-ionizing radiofrequency fields (RFs), which are ubiquitous, resulted in interaction with cellular components. The aim of the study was thus to examine whether exposure of mouse bone marrow stromal cells (BMSC) to RF also resulted in cellular interactions. BMSC were exposed to 900 MHz RF at 120 μW/cm2 power intensity for 4 hr/day for 5 consecutive days. The relative protein expression levels of NF-κB in the cytoplasm and nucleus of RF-exposed cells were compared to non-RF-exposed controls. At 30-min post-RF exposure, a significant decrease in protein expression of NF-κB in the cytoplasm was accompanied by a concomitant increase in nuclear NF-κB protein expression levels. Similar responses were noted in the cytoplasm and nuclear NF-κB levels at 2 hr with a return to control concentrations in primary transcription factor at 24-hr post-RF treatment. Daily incubation of BAY 11-7082, an inhibitor of NF-κB, for 90 min for 5 days followed by RF each day prevented the fall in cytoplasmic NF-κB and rise in nuclear primary transcription factor at 30 min and 2 hr. There were no marked alterations at 24 hr. Data showed that the effects of RF treatment on BMSC involved transient activation of NF-κB which may be attributed to RF-mediated cellular perturbation as evidenced by consequences of BAY 11-7082 inhibition.

Role of NF-κB activation in mouse bone marrow stromal cells exposed to 900 MHz radiofrequency fields (RF)

Nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) is a primary transcription factor which plays a key role in several cellular processes including proliferation and survival. It is well-known that exposure to non-ionizing radiofrequency fields (RF), which are ubiquitous, interact with cellular components. The aim of the study was thus to examine whether exposure of mouse bone marrow stromal cells (BMSC) to RF also resulted in cellular interactions. BMSC were exposed to 900 MHz RF at 120 μW/cm² power intensity for 4 hr/day for 5 consecutive days. The relative protein expression levels of NF-κB in the cytoplasm and nucleus of RF-exposed cells were compared to non-RF-exposed controls. At 30 min post-RF exposure a significant decrease in protein expression of NF-κB in the cytoplasm was accompanied by a concomitant increase in nuclear NF-κB protein expression levels. Similar responses were noted in the cytoplasm and nuclear NF-κB levels at 2 hr with a return to control concentrations in primary transcription factor at 24 hr post-RF treatment. Daily incubation of BAY 11-7082 an inhibitor of NF-κB for 90 min for 5 days followed by RF each day prevented the fall in cytoplasmic NF-κB and rise in nuclear primary transcription factor at 30 min and 2 hr. There were no marked alterations at 24 hr. Data showed that the effects of RF treatment on BMSC involved transient activation of NF-κB which may be attributed to RF-mediated cellular perturbation as evidenced by consequences of BAY 11-7082 inhibition.

Interleukin-6 Interweaves the Bone Marrow Microenvironment, Bone Loss, and Multiple Myeloma

The immune system is strongly linked to the maintenance of healthy bone. Inflammatory cytokines, specifically, are crucial to skeletal homeostasis and any dysregulation can result in detrimental health complications. Interleukins, such as interleukin 6 (IL-6), act as osteoclast differentiation modulators and as such, must be carefully monitored and regulated. IL-6 encourages osteoclastogenesis when bound to progenitors and can cause excessive osteoclastic activity and osteolysis when overly abundant. Numerous bone diseases are tied to IL-6 overexpression, including rheumatoid arthritis, osteoporosis, and bone-metastatic cancers. In the latter, IL-6 can be released with growth factors into the bone marrow microenvironment (BMM) during osteolysis from bone matrix or from cancer cells and osteoblasts in an inflammatory response to cancer cells. Thus, IL-6 helps create an ideal microenvironment for oncogenesis and metastasis. Multiple myeloma (MM) is a blood cancer that homes to the BMM and is strongly tied to overexpression of IL-6 and bone loss. The roles of IL-6 in the progression of MM are discussed in this review, including roles in bone homing, cancer-associated bone loss, disease progression and drug resistance. MM disease progression often includes the development of drug-resistant clones, and patients commonly struggle with reoccurrence. As such, therapeutics that specifically target the microenvironment, rather than the cancer itself, are ideal and IL-6, and its myriad of downstream signaling partners, are model targets. Lastly, current and potential therapeutic interventions involving IL-6 and connected signaling molecules are discussed in this review.

Stabilization of miRNAs in esophageal cancer contributes to radioresistance and limits efficacy of therapy

The five-year survival rate of esophageal cancer patients is less than 20%. This may be due to increased resistance (acquired or intrinsic) of tumor cells to chemo/radiotherapies, often caused by aberrant cell cycle, deregulated apoptosis, increases in growth factor signaling pathways, and/or changes in the proteome network. In addition, deregulation in non-coding RNA-mediated signaling pathways may contribute to resistance to therapies. At the molecular level, these resistance factors have now been linked to various microRNA (miRNAs), which have recently been shown to control cell development, differentiation and neoplasia. The increased stability and dysregulated expression of miRNAs have been associated with increased resistance to various therapies in several cancers, including esophageal cancer. Therefore, miRNAs represent the next generation of molecules with tremendous potential as biomarkers and therapeutic targets. However, detailed studies on miRNA-based therapeutic interventions are still in their infancy. Hence, in this review, we have summarized the current status of microRNAs in dictating the resistance/sensitivity of tumor cells to chemotherapy and radiotherapy. In addition, we have discussed various strategies to increase radiosensitivity, including targeted therapy, and the use of miRNAs as radiosensitive/radioresistance biomarkers for esophageal cancer in the clinical setting.

Temporal clustering analysis of endothelial cell gene expression following exposure to a conventional radiotherapy dose fraction using Gaussian process clustering

The vascular endothelium is considered as a key cell compartment for the response to ionizing radiation of normal tissues and tumors, and as a promising target to improve the differential effect of radiotherapy in the future. Following radiation exposure, the global endothelial cell response covers a wide range of gene, miRNA, protein and metabolite expression modifications. Changes occur at the transcriptional, translational and post-translational levels and impact cell phenotype as well as the microenvironment by the production and secretion of soluble factors such as reactive oxygen species, chemokines, cytokines and growth factors. These radiation-induced dynamic modifications of molecular networks may control the endothelial cell phenotype and govern recruitment of immune cells, stressing the importance of clearly understanding the mechanisms which underlie these temporal processes. A wide variety of time series data is commonly used in bioinformatics studies, including gene expression, protein concentrations and metabolomics data. The use of clustering of these data is still an unclear problem. Here, we introduce kernels between Gaussian processes modeling time series, and subsequently introduce a spectral clustering algorithm. We apply the methods to the study of human primary endothelial cells (HUVECs) exposed to a radiotherapy dose fraction (2 Gy). Time windows of differential expressions of 301 genes involved in key cellular processes such as angiogenesis, inflammation, apoptosis, immune response and protein kinase were determined from 12 hours to 3 weeks post-irradiation. Then, 43 temporal clusters corresponding to profiles of similar expressions, including 49 genes out of 301 initially measured, were generated according to the proposed method. Forty-seven transcription factors (TFs) responsible for the expression of clusters of genes were predicted from sequence regulatory elements using the MotifMap system. Their temporal profiles of occurrences were established and clustered. Dynamic network interactions and molecular pathways of TFs and differential genes were finally explored, revealing key node genes and putative important cellular processes involved in tissue infiltration by immune cells following exposure to a radiotherapy dose fraction.

Profiling circRNA and miRNA of radiation-induced esophageal injury in a rat model

Evidence has also shown that micro ribonucleic acid (miRNA) plays an important role in many cellular processes. However, it is unclear how ionizing radiation causes the miRNA and circular ribonucleic acid (circRNA) expression levels to change and how this change relates to esophageal injury. We analyzed RNA Sequencing (RNA-seq) data from normal esophageal tissue and irradiated esophageal tissues and used computational approaches to identify and characterize differentially expressed miRNAs and circRNAs. We detected 27 miRNAs and 197 circRNAs that had significantly different expression levels after ionizing radiation treatment compared with normal control.Among the 27 miRNAs, 7 miRNAs were down-regulated, and the other 20 were up-regulated. Their target genes were found to be involved in responses to wound, lipid biosynthesis, cell proliferation, cell migration, chemokine activity, hairpin binding, and the cell membrane system. We also found 197 differentially expressed circRNAs in total, of which 87 were up-regulated and 110 were down-regulated. Notably, we found that differentially expressed circRNAs were enriched in cell differentiation, epithelial cell migration, striatum development, protein binding, extracellular exosome, and focal adhesion functions. Of the related processes, sphingolipid metabolism was notable. Many of the differentially expressed circRNAs were involved in sphingolipid metabolism pathways. Cells responded to ionizing radiation (IR) using multiple pathways, which led to sphingolipid metabolism and other immune responses, ultimately leading to esophageal injury.IR-induced esophageal injury is worth studying, especially the dynamic network of circRNA and miRNA. By knowing the regulatory details of related pathways, radiation-related esophageal injury can be prevented, and the efficiency of radiation therapy can be enhanced.

The Role of the Nuclear Factor κB Pathway in the Cellular Response to Low and High Linear Energy Transfer Radiation

Astronauts are exposed to considerable doses of space radiation during long-term space missions. As complete shielding of the highly energetic particles is impracticable, the cellular response to space-relevant radiation qualities has to be understood in order to develop countermeasures and to reduce radiation risk uncertainties. The transcription factor Nuclear Factor κB (NF-κB) plays a fundamental role in the immune response and in the pathogenesis of many diseases. We have previously shown that heavy ions with a linear energy transfer (LET) of 100–300 keV/µm have a nine times higher potential to activate NF-κB compared to low-LET X-rays. Here, chemical inhibitor studies using human embryonic kidney cells (HEK) showed that the DNA damage sensor Ataxia telangiectasia mutated (ATM) and the proteasome were essential for NF-κB activation in response to X-rays and heavy ions. NF-κB’s role in cellular radiation response was determined by stable knock-down of the NF-κB subunit RelA. Transfection of a RelA short-hairpin RNA plasmid resulted in higher sensitivity towards X-rays, but not towards heavy ions. Reverse Transcriptase real-time quantitative PCR (RT-qPCR) showed that after exposure to X-rays and heavy ions, NF-κB predominantly upregulates genes involved in intercellular communication processes. This process is strictly NF-κB dependent as the response is completely absent in RelA knock-down cells. NF-κB’s role in the cellular radiation response depends on the radiation quality.

Evidence for the Involvement of the Master Transcription Factor NF-κB in Cancer Initiation and Progression

Nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) is responsible for the regulation of a large number of genes that are involved in important physiological processes, including survival, inflammation, and immune responses. At the same time, this transcription factor can control the expression of a plethora of genes that promote tumor cell proliferation, survival, metastasis, inflammation, invasion, and angiogenesis. The aberrant activation of this transcription factor has been observed in several types of cancer and is known to contribute to aggressive tumor growth and resistance to therapeutic treatment. Although NF-κB has been identified to be a major contributor to cancer initiation and development, there is evidence revealing its role in tumor suppression. This review briefly highlights the major mechanisms of NF-κB activation, the role of NF-κB in tumor promotion and suppression, as well as a few important pharmacological strategies that have been developed to modulate NF-κB function.

Proton irradiation orchestrates macrophage reprogramming through NFκB signaling

Tumor-associated macrophages (TAMs) represent potential targets for anticancer treatments as these cells play critical roles in tumor progression and frequently antagonize the response to treatments. TAMs are usually associated to an M2-like phenotype, characterized by anti-inflammatory and protumoral properties. This phenotype contrasts with the M1-like macrophages, which exhibits proinflammatory, phagocytic, and antitumoral functions. As macrophages hold a high plasticity, strategies to orchestrate the reprogramming of M2-like TAMs towards a M1 antitumor phenotype offer potential therapeutic benefits. One of the most used anticancer treatments is the conventional X-ray radiotherapy (RT), but this therapy failed to reprogram TAMs towards an M1 phenotype. While protontherapy is more and more used in clinic to circumvent the side effects of conventional RT, the effects of proton irradiation on macrophages have not been investigated yet. Here we showed that M1 macrophages (THP-1 cell line) were more resistant to proton irradiation than unpolarized (M0) and M2 macrophages, which correlated with differential DNA damage detection. Moreover, proton irradiation-induced macrophage reprogramming from M2 to a mixed M1/M2 phenotype. This reprogramming required the nuclear translocation of NFκB p65 subunit as the inhibition of IκBα phosphorylation completely reverted the macrophage re-education. Altogether, the results suggest that proton irradiation promotes NFκB-mediated macrophage polarization towards M1 and opens new perspectives for macrophage targeting with charged particle therapy.

RIBE at an inter-organismic level: A study on genotoxic effects in Daphnia magna exposed to waterborne uranium and a uranium mine effluent

The induction of RIBE (Radiation Induced Bystander Effect) is a non-target effect of low radiation doses that has already been verified at an inter-organismic level in fish and small mammals. Although the theoretical impact in the field of environmental risk assessment (ERA) is possible, there is a gap of knowledge regarding this phenomenon in invertebrate groups and following environmentally relevant exposures. To understand if RIBE should be considered for ERA of radionuclide-rich wastewaters, we exposed Daphnia magna (<24 h and 5d old) to a 2% diluted uranium mine effluent for 48 h, and to a matching dose of waterborne uranium (55.3 μg L^-1). Then the exposed organisms were placed (24 and 48 h) in a clean medium together with non-exposed neonates. The DNA damage observed for the non-exposed organisms was statistically significant after the 24 h cohabitation for both uranium (neonates p = 0.002; 5 d-old daphnids p = <0.001) and uranium mine effluent exposure (only for neonates p = 0.042). After 48 h cohabitation significant results were obtained only for uranium exposure (neonates p = 0.017; 5 d-old daphnids p = 0.013). Although there may be some variability associated to age and exposure duration, the significant DNA damage detected in non-exposed organisms clearly reveals the occurrence of RIBE in D. magna. The data obtained and here presented are a valuable contribution for the discussion about the relevance of RIBE for environmental risk assessment.

Bioluminescence Monitoring of Promoter Activity In Vitro and In Vivo

The application of luciferase reporter genes to provide quantitative outputs for the activation of promoters is a well-established technique in molecular biology. Luciferase catalyzes an enzymatic reaction, which in the presence of the substrate luciferin produces photons of light relative to its molar concentration. The luciferase transgene can be genetically inserted at the first intron of a target gene to act as a surrogate for the gene's endogenous expression in cells and transgenic mice. Alternatively, promoter sequences can be excised and/or amplified from genomic sources or constructed de novo and cloned upstream of luciferase in an expression cassette transfected into cells. More recently, the development of synthetic promoters where the essential components of an RNA polymerase binding site and transcriptional start site are fused with various upstream regulatory sequences are being applied to drive reporter gene expression. We have developed a high-throughput cloning strategy to develop lentiviral luciferase reporters driven by transcription factor activated synthetic promoters. Lentiviruses integrate their payload cassette into the host cell genome, thereby facilitating the study of gene expression not only in the transduced cells but also within all subsequent daughter cells. In this manuscript we describe the design, vector construction, lentiviral transduction, and luciferase quantitation of transcription factor activated reporters (TFARs) in vitro and in vivo.

Bowel Radiation Injury: Complexity of the Pathophysiology and Promises of Cell and Tissue Engineering

Ionizing radiation is effective to treat malignant pelvic cancers, but the toxicity to surrounding healthy tissue remains a substantial limitation. Early and late side effects not only limit the escalation of the radiation dose to the tumor but may also be life-threatening in some patients. Numerous preclinical studies determined specific mechanisms induced after irradiation in different compartments of the intestine. This review outlines the complexity of the pathogenesis, highlighting the roles of the epithelial barrier in the vascular network, and the inflammatory microenvironment, which together lead to chronic fibrosis. Despite the large number of pharmacological molecules available, the studies presented in this review provide encouraging proof of concept regarding the use of mesenchymal stromal cell (MSC) therapy to treat radiation-induced intestinal damage. The therapeutic efficacy of MSCs has been demonstrated in animal models and in patients, but an enormous number of cells and multiple injections are needed due to their poor engraftment capacity. Moreover, it has been observed that although MSCs have pleiotropic effects, some intestinal compartments are less restored after a high dose of irradiation. Future research should seek to optimize the efficacy of the injected cells, particularly with regard to extending their life span in the irradiated tissue. Moreover, improving the host microenvironment, combining MSCs with other specific regenerative cells, or introducing new tissue engineering strategies could be tested as methods to treat the severe side effects of pelvic radiotherapy.

Involvement of SULF2 in y-irradiation-induced invasion and resistance of cancer cells by inducing IL-6 expression

Cancer cells that survive radiotherapy often display enhanced invasiveness and resistance to death stimuli. Previous findings have suggested that ionizing radiation (IR) induces such undesirable effects by stimulating the STAT3/Bcl-XL pathway. To identify novel cellular components that mediate these actions of IR, we irradiated lung cancer cells with sublethal doses of y-rays and screened for the induction of IR-responsive genes by microarray analysis. The genes encoding 2 extracellular proteins, SULF2 and IL-6, were found to be upregulated, and these results were confirmed by polymerase chain reactions and western blot analyses. Because the IR-mediated induction of SULF2 was a novel finding, we also confirmed the phenomenon in vivo using xenograft tumors in mice. Analyses of signaling processes revealed that IR induced SULF2 expression via p53, which then promoted IL-6 expression by stabilizing β-catenin, followed by stimulation of the STAT3/Bcl-XL pathway. Consistently, both SULF2 and IL-6 mediated IR-induced invasion and resistance to death stimuli. To investigate whether SULF2 contributes to IR-induced tumor metastasis, we irradiated tumors in mice with sublethal doses of IR. This treatment promoted the entry of tumor cells into the blood stream (intravasation), which was abolished by downregulating SULF2 expression in tumor cells. These results demonstrated that SULF2 can mediate the detrimental effects of IR in vivo. Therefore, SULF2 may be potentially used as a therapeutic and diagnostic target to predict and overcome the malignant effects of IR, particularly in tumors expressing p53 wild-type.

Bromoethylindole (BEI-9) redirects NF-κB signaling induced by camptothecin and TNFα to promote cell death in colon cancer cells

Chemotherapeutic regimens containing camptothecin (CPT), 5-fluorouracil, and oxaliplatin are used to treat advanced colorectal cancer. We previously reported that an indole derivative, 3-(2-bromoethyl)indole (BEI-9), inhibited the proliferation of colon cancer cells and suppressed NF-κB activation. Here, we show that a combination of BEI-9 with either CPT or tumor necrosis factor alpha (TNFα) enhances cell death. Using colorectal cancer cells, we examined the activation of NF-κB by drugs, the potential of BEI-9 for inhibiting drug-induced NF-κB activation, and the enhancement of cell death by combination treatments. Cells were treated with the chemotherapeutic drugs alone or in combination with BEI-9. NF-κB activation, cell cycle profiles, DNA-damage response, markers of cell death signaling and targets of NF-κB were evaluated to determine the effects of single and co-treatments. The combination of BEI-9 with CPT or TNFα inhibited NF-κB activation and reduced the expression of NF-κB-responsive genes, Bcl-xL and COX2. Compared to CPT or BEI-9 alone, sequential treatment of the cells with CPT and BEI-9 significantly enhanced caspase activation and cell death. Co-treatment with TNFα and BEI-9 also caused more cytotoxicity than TNFα or BEI-9 alone. Combined BEI-9 and TNFα enhanced cell death through caspase activation and cleavage of the switch-protein, RIP1 kinase. BEI-9 reduced the expression of COX2 both alone and in combination with CPT or TNF. We postulate that BEI-9 enhances the effects of these drugs on cancer cells by turning off or redirecting NF-κB signaling. Therefore, the combination of BEI-9 with drugs that activate NF-κB needs to be evaluated for clinical applications.

The role of Nuclear Factor-kappa B signaling in human cervical cancer

Background The Nuclear Factor kappaB (NF-kB) family consists of transcription factors that play a complex and essential role in the regulation of immune responses and inflammation. NF-kB has recently generated considerable interest as it has been implicated in human cancer initiation, progression and resistance to treatment. In the present comprehensive review the different aspects of NF-kB signaling in the carcinogenesis of cancer of the uterine cervix are discussed. NF-kB functions as part of a network, which determines the pattern of its effects on the expression of several other genes (such as crosstalks with reactive oxygen species, p53, STAT3 and miRNAS) and thus its function. Activation of NF-kB triggered by a HPV infection is playing an important role in the innate and adaptive immune response of the host. The virus induces down regulation of NF-kB to liquidate the inhibitory activity for its replication triggered by the immune system leading a status of persistant HPV infection. During the progression to high grade intraepithelial neoplasia and cervical cancer NF-KB becomes constitutionally activated again. Mutations in NF-kB genes are rare in solid tumors but mutations of upstream signaling molecules such as RAS, EGFR, PGF, HER2 have been implicated in elevated NF-kB signaling. NF-kB can stimulate transcription of proliferation regulating genes (eg. cyclin D1 and c-myc), genes involved in metastasis, VEGF dependent angiogenesis and cell immortality by telomerase. NF-kB activation can also induce the expression of activation-induced cytodine deaminase (AID) and the APOBEC proteins, providing a mechanistic link between the NF-kB pathway and mutagenic characteristic of cervical cancer. Inhibition of NF-kB has the potential to be used to reverse resistance to radiotherapy and systemic anti-cancer medication, but currently no clinicaly active NF-kB targeting strategies are available.

DMAPT inhibits NF-κB activity and increases sensitivity of prostate cancer cells to X-rays in vitro and in tumor xenografts in vivo

Constitutive activation of the pro-survival transcription factor NF-κB has been associated with resistance to both chemotherapy and radiation therapy in many human cancers, including prostate cancer. Our lab and others have demonstrated that the natural product parthenolide can inhibit NF-κB activity and sensitize PC-3 prostate cancers cells to X-rays in vitro; however, parthenolide has poor bioavailability in vivo and therefore has little clinical utility in this regard. We show here that treatment of PC-3 and DU145 human prostate cancer cells with dimethylaminoparthenolide (DMAPT), a parthenolide derivative with increased bioavailability, inhibits constitutive and radiation-induced NF-κB binding activity and slows prostate cancer cell growth. We also show that DMAPT increases single and fractionated X-ray-induced killing of prostate cancer cells through inhibition of DNA double strand break repair and also that DMAPT-induced radiosensitization is, at least partially, dependent upon the alteration of intracellular thiol reduction-oxidation chemistry. Finally, we demonstrate that the treatment of PC-3 prostate tumor xenografts with oral DMAPT in addition to radiation therapy significantly decreases tumor growth and results in significantly smaller tumor volumes compared to xenografts treated with either DMAPT or radiation therapy alone, suggesting that DMAPT might have a potential clinical role as a radiosensitizing agent in the treatment of prostate cancer.

Akt1/NFκB signaling pathway activation by a small molecule DMA confers radioprotection to intestinal epithelium in xenograft model

Normal tissue protection and recovery of radiation-induced damage are of paramount importance for development of radioprotector. Radioprotector which selectively protects normal tissues over cancerous tissues improves the therapeutic window of radiation therapy. In the present study, small bisbenzimidazole molecule, DMA (5-(4-methylpiperazin-1-yl)-2-[2'-(3,4-dimethoxy-phenyl)-5'-benzimidazolyl]-benzimidazole) was evaluated for in vivo radioprotective effects to selectively protect normal tissue over tumor with underlying molecular mechanism. Administration of single DMA dose prior to radiation has enhanced survival of Balb/c mice against sublethal and supralethal total body irradiation. DMA ameliorated radiation-induced damage of normal tissues such as hematopoietic (HP) and gastrointestinal tract (GI) system. Oxidative stress marker Malondialdehyde level was decreased by DMA whereas it maintained endogenous antioxidant status by increasing the level of reduced glutathione, glutathione reductase, glutathione-s-transferase, superoxide dismutase and total thiol content in hepatic tissue of irradiated mice. Mechanistic studies revealed that DMA treatment prior to radiation leads to Akt1/NFκB signaling which reduced radiation-induced genomic instability in normal cells. However, these pathways were not activated in tumor tissues when subjected to DMA treatment in similar conditions. Abrogation of Akt1 and NFκB genes resulted in no radioprotection by DMA and enhanced apoptosis against radiation. Plasma half-life of DMA was 3.5h and 2.65h at oral and intravenous dose respectively and 90% clearance was observed in 16h. In conclusion, these data suggests that DMA has potential to be developed as a safe radioprotective agent for radiation countermeasures and an adjuvant in cancer therapy.

Protective effect of Salvia miltiorrhiza Bunge on 5-fluorouracil-induced oral mucositis

Oral mucositis is a common side-effect caused by chemotherapy or radiotherapy occurring in the majority of cancer patients and is characterized by inflammation and ulcers in the oral mucosa. In the present study, we examined the protective effects of Salvia miltiorrhiza Bunge (SM) on oral mucositis induced by 5-fluorouracil (5-FU) in human pharyngeal cells and golden Syrian hamsters. We investigated the proliferation and antioxidant abilities of SM using MTT, 2-diphenyl-1-picrylhydrazyl (DPPH) and reactive oxygen species (ROS) assays in vitro. Additionally, TUNEL assay was performed, and the expression levels of nuclear factor-κB (NF-κB), caspase-3 and proinflammatory cytokines were assessed by immunoblotting. The results showed that SM increased the cell proliferation rate in human pharyngeal cells up to 128.97±9.7% compared with this rate in the untreated cells and exerted protective effects on mucosal injury caused by 5-FU treatment. In addition, all concentrations of SM increased DPPH scavenging ability and blocked ROS generation in the treated cells. Taken together, following SM treatment, expression of NF-κB and cleaved caspase-3 were significantly decreased followed by inhibition of cell death. These data suggest that SM could be used for the prevention and treatment of oral mucositis caused by cancer therapies.

Sp1-mediated transcriptional activation of miR-205 promotes radioresistance in esophageal squamous cell carcinoma

Radiotherapy for esophageal squamous cell carcinoma (ESCC) patients is limited by resistance to ionizing radiation (IR). However, the roles and mechanisms of microRNAs in radioresistance are obscure. Here, we investigated that microRNA-205 (miR-205) was upregulated in radioresistant (RR) ESCC cells compared with the parental cells. Overexpression of miR-205 promoted colony survival post-IR, whereas depletion of miR-205 sensitized ESCC cells to IR in vitro and in vivo. Further, we demonstrated that miR-205 promoted radioresistance by enhancing DNA repair, inhibiting apoptosis and activating epithelial-mesenchymal transition (EMT). Mechanistically, miR-205, upregulated post-IR, was demonstrated to be activated by Sp1 in parallel with its host gene, miR-205HG, both of which showed a perfect correlation. We also identified and validated phosphatase and tensin homolog (PTEN), as a target of miR-205 that promoted radioresistance via PI3K/AKT pathway. Lastly, increased miR-205 expression was closely associated with decreased PTEN expression in ESCC tissues and miR-205 expression predicted poor prognosis in patients with ESCC. Taken together, these findings identify miR-205 as a critical determinant of radioresistance and a biomarker of prognosis. The Sp1-mediated transcriptional activation of miR-205 promotes radioresistance through PTEN via PI3K/AKT pathway in ESCC. Inhibition of miR-205 expression may be a new strategy for radiotherapy in ESCC.