Markers Useful in Monitoring Radiation-Induced Lung Injury in Lung Cancer Patients: A Review

Microbiome in radiotherapy: an emerging approach to enhance treatment efficacy and reduce tissue injury

Radiotherapy is a widely used cancer treatment that utilizes powerful radiation to destroy cancer cells and shrink tumors. While radiation can be beneficial, it can also harm the healthy tissues surrounding the tumor. Recent research indicates that the microbiota, the collection of microorganisms in our body, may play a role in influencing the effectiveness and side effects of radiation therapy. Studies have shown that specific species of bacteria living in the stomach can influence the immune system's response to radiation, potentially increasing the effectiveness of treatment. Additionally, the microbiota may contribute to adverse effects like radiation-induced diarrhea. A potential strategy to enhance radiotherapy outcomes and capitalize on the microbiome involves using probiotics. Probiotics are living microorganisms that offer health benefits when consumed in sufficient quantities. Several studies have indicated that probiotics have the potential to alter the composition of the gut microbiota, resulting in an enhanced immune response to radiation therapy and consequently improving the efficacy of the treatment. It is important to note that radiation can disrupt the natural balance of gut bacteria, resulting in increased intestinal permeability and inflammatory conditions. These disruptions can lead to adverse effects such as diarrhea and damage to the intestinal lining. The emerging field of radiotherapy microbiome research offers a promising avenue for optimizing cancer treatment outcomes. This paper aims to provide an overview of the human microbiome and its role in augmenting radiation effectiveness while minimizing damage.

Development of a Radiation-induced Pulmonary Fibrosis Partial Body Irradiation Model in C57BL/6 Mice

With the current volatile geopolitical climate, the threat of nuclear assault is high. Exposure to ionizing radiation from either nuclear incidents or radiological accidents often lead to major harmful consequences to human health. Depending on the absorbed dose, the symptoms of the acute radiation syndrome and delayed effects of acute radiation exposure (DEARE) can appear within hours, weeks to months. The lung is a relatively radiosensitive organ with manifestation of radiation pneumonitis as an acute effect, followed by apparent fibrosis in weeks or even months. A recently developed, first-of-its-kind murine model for partial-body irradiation (PBI) injury, which can be used to test potential countermeasures against multi-organ damage such as gastrointestinal (GI) tract and lungs was used for irradiation, with 2.5% bone marrow spared (BM2.5-PBI) from radiation exposure. Long-term damage to lungs from radiation was evaluated using µ-CT scans, pulmonary function testing, histopathological parameters and molecular biomarkers. Pulmonary fibrosis was detected by ground glass opacity observed in µ-CT scans of male and female C57BL/6J mice 6-7 months after BM2.5-PBI. Lung mechanics assessments pertaining to peripheral airways suggested fibrotic lungs with stiffer parenchymal lung tissue and reduced inspiratory capacity in irradiated animals 6-7 months after BM2.5-PBI. Histopathological evaluation of the irradiated lungs revealed presence of focal and diffuse pleural, and parenchymal inflammatory and fibrotic lesions. Fibrosis was confirmed by elevated levels of collagen when compared to lungs of age-matched naïve mice. These findings were validated by findings of elevated levels of pro-fibrotic biomarkers and reduction in anti-inflammatory proteins. In conclusion, a long-term model for radiation-induced pulmonary fibrosis was established, and countermeasures could be screened in this model for survival and protection/mitigation or recovery from radiation-induced pulmonary damage.

Associations between patient-reported late effects and systemic cytokines in long-term survivors of head and neck cancer treated with radiotherapy

PURPOSE

Head and neck cancer (HNC) treatment may lead to late effects and impaired health-related quality of life of survivors. Knowledge on long-term late effects after radiotherapy (RT) and potential underlying biological mechanisms is lacking. We assessed the prevalence of xerostomia, dysphagia, and chronic fatigue (CF) in HNC survivors ≥ 5 years post-RT, and examined associations between pro-inflammatory cytokines and late effects.

METHODS

In a cross-sectional study, 263 HNC survivors treated between 2007 and 2013 were enrolled. They completed validated questionnaires assessing xerostomia and dysphagia (the EORTC QLQ-H&N35), and CF (the Fatigue Questionnaire), and underwent blood sampling and clinical examination. Pro-inflammatory cytokines were analyzed in 262 survivors and 100 healthy age- and gender-matched controls.

RESULTS

Median time since treatment was 8.5 years. The proportions of survivors reporting xerostomia, dysphagia, and CF were 58%, 31%, and 33%, respectively, with a preponderance of females. We found no significant associations between IL-6, IL-8, IP-10, TARC, TNF, or ENA-78 and the three late effects. The odds of having elevated levels of IL-6 and IP-10 were significantly higher in the survivors compared to the controls.

CONCLUSIONS

More than one-third of long-term HNC survivors experienced xerostomia, dysphagia, and CF. Persistent inflammation, with elevated systemic cytokines, was not associated with these late effects, although HNC survivors had higher levels of some cytokines than the controls.

IMPLICATIONS FOR CANCER SURVIVORS

This study provides new knowledge on late effects that can serve as grounds for informing patients with HNC about risk of late effects more than 5 years after RT.

IDO1 Activity Predicts Lung Toxicity in Patients with Unresectable Stage III NSCLC and Chemoradiotherapy

Objectives

Indoleamine 2,3-dioxygenase 1 (IDO1) acts as the key rate-limiting enzyme that converts tryptophan (Trp) to kynurenine (Kyn). Its activity was primarily induced by interferon-γ (IFN-γ), which was reported to play a role in the development of acute radiation-induced pneumonitis. In this study, we aimed to investigate the correlation between IDO1 activity and radiation-induced lung toxicity (RILT) in stage III nonsmall cell lung cancer (NSCLC) patients who were treated with chemoradiotherapy (CRT).

Materials and Methods

Systemic IDO1 activity was reflected by Kyn : Trp ratio. Plasma levels of Kyn and Trp in 113 stage III NSCLC patients were measured by high-performance liquid chromatography (HPLC) before the initiation of radiotherapy. Dynamic change of IDO1 activity was followed in 23 patients before, during, and after radiotherapy. We also used RNA sequencing (RNA-seq) data from the Cancer Genome Atlas Program (TCGA) database and performed gene set enrichment analysis (GSEA) to explore how IDO1 was involved in the development of RILT.

Results

9.7% (11/113) of the whole group developed G3+ (greater than or equal to Grade 3) RILT. Preradiation IDO1 activity was significantly higher in patients who developed G3 + RILT than in nonG3 + RILT patients. (P = 0.029, AUC = 0.70). Univariate and multivariate analyses showed that high IDO1 activity was independently associated with the risk of G3 + RILT (P = 0.034). A predictive model combining both IDO1 activity and FEV1 was established for severe RILT and displayed a moderate predictive value (AUC = 0.83, P < 0.001). The incidence of G3 + RILT was 2.6% (1/38) in patients with an IDO activity ≤0.069 and FEV1 > 59.4%, and 50.0% (6/12) in those with an IDO activity >0.069 and FEV1 ≤ 59.4%. Of 23 patients with dynamic tracking, the IDO1 activity of postradiation was significantly lower than midradiation (P = 0.021), though no significant differences among the three time points were observed (P = 0.070). Bioinformatic analysis using RNA-seq data from 1014 NSCLC patients revealed that IDO mainly functioned in the inflammatory response instead of the late fibrosis process in NSCLC patients.

Conclusion

High baseline IDO1 activity combined with unfavorable baseline FEV1 was predictive of severe RILT in unresectable stage III NSCLC patients. IDO1 might play a role in the acute inflammatory response. Finding effective interventions to alleviate RILT using IDO inhibitors is warranted in the future.

Targeting Mitochondrial Metabolism to Reverse Radioresistance: An Alternative to Glucose Metabolism

Radiotherapy failure and poor tumor prognosis are primarily attributed to radioresistance. Improving the curative effect of radiotherapy and delaying cancer progression have become difficult problems for clinicians. Glucose metabolism has long been regarded as the main metabolic process by which tumor cells meet their bioenergetic and anabolic needs, with the complex interactions between the mitochondria and tumors being ignored. This misconception was not dispelled until the early 2000s; however, the cellular molecules and signaling pathways involved in radioresistance remain incompletely defined. In addition to being a key metabolic site that regulates tumorigenesis, mitochondria can influence the radiation effects of malignancies by controlling redox reactions, participating in oxidative phosphorylation, producing oncometabolites, and triggering apoptosis. Therefore, the mitochondria are promising targets for the development of novel anticancer drugs. In this review, we summarize the internal relationship and related mechanisms between mitochondrial metabolism and cancer radioresistance, thus exploring the possibility of targeting mitochondrial signaling pathways to reverse radiation insensitivity. We suggest that attention should be paid to the potential value of mitochondria in prolonging the survival of cancer patients.

Serum RNA biomarkers for predicting survival in non-human primates following thoracic radiation

In a mass radiation exposure, the healthcare system may rely on differential expression of miRNA to determine exposure and effectively allocate resources. To this end, miRNome analysis was performed on non-human primate serum after whole thorax photon beam irradiation of 9.8 or 10.7 Gy with dose rate 600 cGy/min. Serum was collected up to 270 days after irradiation and sequenced to determine immediate and delayed effects on miRNA expression. Elastic net based GLM methods were used to develop models that predicted the dose vs. controls at 81% accuracy at Day 15. A three-group model at Day 9 achieved 71% accuracy in determining if an animal would die in less than 90 days, between 90 and 269 days, or survive the length of the study. At Day 21, we achieved 100% accuracy in determining whether an animal would later develop pleural effusion. These results demonstrate the potential ability of miRNAs to determine thorax partial-body irradiation dose and forecast survival or complications early following whole thorax irradiation in large animal models. Future experiments incorporating additional doses and independent animal cohorts are warranted to validate these results. Development of a serum miRNA assay will facilitate the administration of medical countermeasures to increase survival and limit normal tissue damage following a mass exposure.

Radiation-assisted reduction of graphene oxide by aloe vera and ginger and their antioxidant and anti-inflammatory roles against male mice liver injury induced by gamma radiation

A novel approach for graphene oxide reduction using γ-rays in the presence of natural antioxidants is revealed for biomedical applications.

Gut Microbiota-Derived PGF2α Fights against Radiation-Induced Lung Toxicity through the MAPK/NF-κB Pathway

Radiation pneumonia is a common and intractable side effect associated with radiotherapy for chest cancer and involves oxidative stress damage and inflammation, prematurely halting the remedy and reducing the life quality of patients. However, the therapeutic options for the complication have yielded disappointing results in clinical application. Here, we report an effective avenue for fighting against radiation pneumonia. Faecal microbiota transplantation (FMT) reduced radiation pneumonia, scavenged oxidative stress and improved lung function in mouse models. Local chest irradiation shifted the gut bacterial taxonomic proportions, which were preserved by FMT. The level of gut microbiota-derived PGF2α decreased following irradiation but increased after FMT. Experimental mice with PGF2α replenishment, via an oral route, exhibited accumulated PGF2α in faecal pellets, peripheral blood and lung tissues, resulting in the attenuation of inflammatory status of the lung and amelioration of lung respiratory function following local chest irradiation. PGF2α activated the FP/MAPK/NF-κB axis to promote cell proliferation and inhibit apoptosis with radiation challenge; silencing MAPK attenuated the protective effect of PGF2α on radiation-challenged lung cells. Together, our findings pave the way for the clinical treatment of radiotherapy-associated complications and underpin PGF2α as a gut microbiota-produced metabolite.

Promising Biomarkers of Radiation-Induced Lung Injury: A Review

Radiation-induced lung injury (RILI) is one of the main dose-limiting side effects in patients with thoracic cancer during radiotherapy. No reliable predictors or accurate risk models are currently available in clinical practice. Severe radiation pneumonitis (RP) or pulmonary fibrosis (PF) will reduce the quality of life, even when the anti-tumor treatment is effective for patients. Thus, precise prediction and early diagnosis of lung toxicity are critical to overcome this longstanding problem. This review summarizes the primary mechanisms and preclinical animal models of RILI reported in recent decades, and analyzes the most promising biomarkers for the early detection of lung complications. In general, ideal integrated models considering individual genetic susceptibility, clinical background parameters, and biological variations are encouraged to be built up, and more prospective investigations are still required to disclose the molecular mechanisms of RILI as well as to discover valuable intervention strategies.

New Insights on Old Biomarkers Involved in Tumor Microenvironment Changes and Their Diagnostic Relevance in Non-Small Cell Lung Carcinoma

BACKGROUND

Lung cancer is a multifactorial disease with a heterogeneous tumor group that hampers diagnostic and therapeutic approaches, as well as understanding of the processes that underlie its pathogenesis. Current research efforts are focused on examining alterations in the tumor microenvironment, which may affect the pathogenesis and further malignant progression in lung cancer. The aim of this study was to investigate changes in the levels of biomarkers involved in the lung tumor microenvironment and their diagnostic utility in differentiating lung cancer subtypes and stages.

METHODS

This study comprised 112 lung cancer patients, 50 with adenocarcinoma, 35 with squamous cell carcinoma, 13 with other non-small cell lung carcinoma subtypes, and 14 with other lung neoplasms than non-small cell lung carcinoma. Tumor markers (CEA, CYFRA 21-1, and NSE) were measured in the patients' sera and plasmas, along with IL-6, TNF-α, SAA1, CRP, MMP-2, MMP-9, glucose, lactate, and LDH, utilizing enzyme-linked immunosorbent assays, enzyme immunoassays, and automated clinical chemistry and turbidimetry systems. The results were statistically analyzed across patient groups based on the subtype and stage of lung cancer.

RESULTS

Glucose concentrations showed statistically significant (p < 0.05) differences both between lung cancer subtypes and stages, with the highest levels in patients with other lung neoplasms (me = 130.5 mg/dL) and in patients with stage IIB lung cancer (me = 132.0 mg/dL). In patients with advanced lung cancer, IL-6 and LDH had considerably higher concentration and activity. There was also a significant positive correlation between IL-6 and MMP-9 in adenocarcinoma and SqCC, with correlation coefficients of 0.53 and 0.49, respectively. The ROC analyses showed that the best single biomarkers for distinguishing adenocarcinoma from squamous cell carcinoma are glucose, CRP, and CYFRA 21-1; however, their combination did not significantly improve sensitivity, specificity, and the AUC value. The combinations of IL-6, glucose, LDH and CEA, IL-6, SAA1, MMP-9, and lactate can distinguish patients with stage IIB lung cancer from those with stage IIA with 100% sensitivity, 100% specificity, and with an AUC value of 0.8333 and 1.0000, respectively, whereas the combination of CEA, IL-6, and LDH can identify patients with stage IIIA lung cancer from those with stage IIB with 72.73% sensitivity, 94.44% specificity, and an AUC value of 0.8686.

CONCLUSION

There is a link between biomarkers of tumor microenvironment changes and tumor markers, and combinations of these markers may be clinically useful in the differential diagnosis of adenocarcinoma and squamous cell carcinoma, as well as lung cancer stages IIB and IIA, and IIIA and IIB.

Radiation Biomarkers: Silver Bullet, or Wild Goose Chase?

Humans have learned to harness the power of radiation for therapeutic ends, with 50% of all patients diagnosed with cancer undergoing radiotherapy as part of their treatment [...].

Cytokine Profiles of Non-Small Cell Lung Cancer Patients Treated with Concurrent Chemoradiotherapy with Regards to Radiation Pneumonitis Severity

The immunologic aspects of radiation pneumonitis (RP) are unclear. We analyzed variations in cytokine profiles between patients with grade (Gr) 0–1 and Gr ≥ 2 RP. Fifteen patients undergoing concurrent chemoradiotherapy for non-small cell lung cancer were included. Blood samples of 9 patients with Gr 0–1 and 6 with Gr ≥ 2 RP were obtained from the Biobank. Cytokine levels were evaluated using an enzyme linked immunosorbent assay at before radiotherapy (RT) initiation, 1, 3, and 6 weeks post-RT initiation, and 1 month post-RT completion. Concentrations of granulocyte colony-stimulating factor (G-CSF), interleukin (IL)-6, IL-10, IL-13, IL-17, interferon (IFN)-γ, tumor necrosis factor (TNF)-α, and transforming growth factor (TGF)-β were analyzed; none were related to the occurrence of Gr ≥ 2 RP at pre-RT initiation. At 3 weeks, relative changes in the G-CSF, IL-6, and IFN-γ levels differed significantly between the groups (p = 0.026, 0.05 and 0.026, respectively). One month post-RT completion, relative changes of IL-17 showed significant differences (p = 0.045); however, relative changes in TNF-α, IL-10, IL-13, and TGF-β, did not differ significantly. Evaluation of changes in IL-6, G-CSF, and IFN-γ at 3 weeks after RT initiation can identify patients pre-disposed to severe RP. The mechanism of variation in cytokine levels in relation to RP severity warrants further investigation.