T cell epigenetic remodeling and accelerated epigenetic aging are linked to long-term immune alterations in childhood cancer survivors

Associations of seven measures of biological age acceleration with frailty and all-cause mortality among adult survivors of childhood cancer in the St. Jude Lifetime Cohort

Survivors of childhood cancer may experience accelerated biological aging, resulting in premature frailty and death. We used seven measures of biological age in the St. Jude Lifetime (SJLIFE) Cohort to compare biological age acceleration between the SJLIFE Cohort and the third United States National Health and Nutrition Examination Survey controls, explore trajectories of biological age according to cancer treatment and type, and test associations of biological age acceleration with frailty and death (mean follow-up of 26.5 years) among survivors. Survivors of cancer aged 5% faster per year and measured, on average, 0.6-6.44 years biologically older compared to controls and 5-16 years biologically older compared to age-matched individuals at the population level. Survivors treated with hematopoietic cell transplant and vinca alkaloid chemotherapy evidenced the fastest trajectories of biological aging. Biologically, older and faster-aging survivors consistently and robustly had a higher risk of frailty and died earlier than those with slower biological aging, suggesting a potential opportunity to intervene on excess aging.

Epigenetics as a determinant of radiation response in cancer

Radiation therapy is a cornerstone of modern cancer treatment. Treatment is based on depositing focal radiation to the tumor to inhibit cell growth, proliferation and metastasis, and to promote the death of cancer cells. In addition, radiation also affects non-tumor cells in the tumor microenvironmental (TME). Radiation resistance of the tumor cells is the most common cause of treatment failure, allowing survival of cancer cell and subsequent tumor growing. Molecular radioresistance comprises genetic and epigenetic characteristics inherent in cancer cells, or characteristics acquired after exposure to radiation. Furthermore, cancer stem cells (CSCs) and non-tumor cells into the TME as stromal and immune cells have a role in promoting and maintaining radioresistant tumor phenotypes. Different regulatory molecules and pathways distinctive of radiation resistance include DNA repair, survival signaling and cell death pathways. Epigenetic mechanisms are one of the most relevant events that occur after radiotherapy to regulate the expression and function of key genes and proteins in the differential radiation-response. This article reviews recent data on the main molecular mechanisms and signaling pathways related to the biological response to radiotherapy in cancer; highlighting the epigenetic control exerted by DNA methylation, histone marks, chromatin remodeling and m6A RNA methylation on gene expression and activation of signaling pathways related to radiation therapy response.

Irradiation-Induced Dysbiosis: The Compounding Effect of High-Fat Diet on Metabolic and Immune Functions in Mice

The negative impact of irradiation or diet on the metabolic and immune profiles of cancer survivors have been previously demonstrated. The gut microbiota plays a critical role in regulating these functions and is highly sensitive to cancer therapies. The aim of this study was to investigate the effect of irradiation and diet on the gut microbiota and metabolic or immune functions. We exposed C57Bl/6J mice to a single dose of 6 Gy radiation and after 5 weeks, fed them a chow or high-fat diet (HFD) for 12 weeks. We characterised their faecal microbiota, metabolic (whole body and adipose tissue) functions, and systemic (multiplex cytokine, chemokine assay, and immune cell profiling) and adipose tissue inflammatory profiles (immune cell profiling). At the end of the study, we observed a compounding effect of irradiation and diet on the metabolic and immune profiles of adipose tissue, with exposed mice fed a HFD displaying a greater inflammatory signature and impaired metabolism. Mice fed a HFD also showed altered microbiota, irrespective of irradiation status. An altered diet may exacerbate the detrimental effects of irradiation on both the metabolic and inflammatory profiles. This could have implications for the diagnosis and prevention of metabolic complications in cancer survivors exposed to radiation.

Long-Term Immunological Consequences of Radiation Exposure in a Diverse Cohort of Rhesus Macaques

PURPOSE

The aim of this study was to develop an improved understanding of the delayed immunologic effects of acute total body irradiation (TBI) using a diverse cohort of nonhuman primates as a model for an irradiated human population.

METHODS AND MATERIALS

Immune recovery was evaluated in 221 rhesus macaques either left unirradiated (n = 36) or previously irradiated (n = 185) at 1.1 to 8.5 Gy TBI (median, 6.5 Gy) when aged 2.1 to 15.5 years (median, 4.2 years). Blood was drawn annually for up to 5 years total between 0.5 and 14.3 years after exposure. Blood was analyzed by complete blood count, immunophenotyping of monocytes, dendritic cells (DC) and lymphocytes by flow cytometry, and signal joint T-cell receptor exclusion circle quantification in isolated peripheral blood CD4 and CD8 T cells. Animals were categorized by age, irradiation status, and time since irradiation. Sex-adjusted means of immune metrics were evaluated by generalized estimating equation models to identify cell populations altered by TBI.

RESULTS

Overall, the differences between irradiated and nonirradiated animals were subtle and largely restricted to younger animals and select cell populations. Subsets of monocytes, DC, T cells, and B cells showed significant interaction effects between radiation dose and age after adjustment for sex. Irradiation at a young age caused transient increases in the percentage of peripheral blood myeloid DC and dose-dependent changes in monocyte balance for at least 5 years after TBI. TBI also led to a sustained decrease in the percentage of circulating memory B cells. Young irradiated animals exhibited statistically significant and prolonged disruption of the naïve/effector memory/central memory CD4 and CD8 T-cell equilibrium and exhibited a dose-dependent increase in thymopoiesis for 2 to 3 years after exposure.

CONCLUSIONS

This study indicates TBI subtly but significantly alters the circulating proportions of cellular mediators of adaptive immune memory for several years after irradiation, especially in macaques under 5 years of age and those receiving a high dose of radiation.

Premature aging in childhood cancer survivors

Progress in medicine has increased the survival time of children suffering from cancer; >80% of patients survive for at least 5 years from the end of treatment. However, there are late effects of anticancer therapy, which accompany this success. Two-thirds of childhood cancer survivors (CCSs) have at least one late effect (any side effects or complications of anticancer treatment that appear months to years after the completion of treatment), e.g. endocrinopathies, cardiovascular diseases or subsequent cancers, and half of these late effects are serious or life threatening. These late consequences of childhood cancer treatment pose a serious health, social and economic problem. A common mechanism for developing a number of late effects is the onset of premature biological aging, which is associated with the early onset of chronic diseases and death. Cellular senescence in cancer survivors is caused by therapy that can induce chromosomal aberrations, mutations, telomere shortening, epigenetic alterations and mitochondrial dysfunctions. The mechanisms of accelerated aging in cancer survivors have not yet been fully clarified. The measurement of biological age in survivors can help improve the understanding of aging mechanisms and identify risk factors for premature aging. However, to the best of our knowledge, no single marker for the evaluation of biological or functional age is known, so it is therefore necessary to measure the consequences of anticancer treatment using complex assessments. The present review presents an overview of premature aging in CCSs and of the mechanisms involved in its development, focusing on the association of senescence and late effects.

Effect of metformin on the epigenetic age of peripheral blood in patients with diabetes mellitus

Background: Metformin has been proven to have an antiaging effect. However, studies on how metformin affects global epigenetic regulation and its effect on the epigenetic clock in diabetes mellitus (DM) patients are limited. This study aims to investigate the impact of metformin on the epigenetic age in subjects with type 2 DM.

Results: We collected the peripheral blood of the metformin group and the no-metformin group of the 32 DM patients. Three previously established epigenetic clocks (Hannum, Horvath, and DNAmPhenoAge) were used to estimate the epigenetic age acceleration of the two groups. We defined biological age acceleration for each group by comparing the estimated biological age with the chronological age. Results were presented as follows: 1) all three epigenetic clocks were strongly correlated with chronological age. 2) We found a strong association between metformin intake and slower epigenetic aging by Horvath’s clock and Hannum’s clock.

Conclusions: Here, we found an association between metformin intake and slower epigenetic aging.

Osteoporosis in Childhood Cancer Survivors: Physiopathology, Prevention, Therapy and Future Perspectives

Simple Summary

Anti-cancer treatments induced an increase in the childhood cancer survival rate. However, they are responsible for several long-term side effects in childhood cancer survivors, including osteoporosis. Cancer itself, a sedentary lifestyle, and an unhealthy diet might adversely affect bone health. Early identification and adequate management of bone fragility in childhood cancer survivors could be useful to prevent osteoporosis onset and consequently fragility fractures.

Abstract

The improvement of chemotherapy, radiotherapy, and surgical interventions, together with hematopoietic stem cell transplantation, increased childhood cancer survival rate in the last decades, reaching 80% in Europe. Nevertheless, anti-cancer treatments are mainly responsible for the onset of long-term side effects in childhood cancer survivors (CCS), including alterations of the endocrine system function and activity. In particular, the most frequent dysfunction in CCS is a metabolic bone disorder characterized by low bone mineral density (BMD) with increased skeletal fragility. BMD loss is also a consequence of a sedentary lifestyle, malnutrition, and cancer itself could affect BMD, thus inducing osteopenia and osteoporosis. In this paper, we provide an overview of possible causes of bone impairment in CCS in order to propose management strategies for early identification and treatment of skeletal fragility in this population.

Immunosenescence in Childhood Cancer Survivors and in Elderly: A Comparison and Implication for Risk Stratification

The population of childhood cancer survivors (CCS) has grown rapidly in recent decades. Although cured of their original malignancy, these individuals are at increased risk of serious late effects, including age-associated complications. An impaired immune system has been linked to the emergence of these conditions in the elderly and CCS, likely due to senescent immune cell phenotypes accompanied by low-grade inflammation, which in the elderly is known as "inflammaging." Whether these observations in the elderly and CCS are underpinned by similar mechanisms is unclear. If so, existing knowledge on immunosenescent phenotypes and inflammaging might potentially serve to benefit CCS. We summarize recent findings on the immune changes in CCS and the elderly, and highlight the similarities and identify areas for future research. Improving our understanding of the underlying mechanisms and immunosenescent markers of accelerated immune aging might help us to identify individuals at increased risk of serious health complications.

Anti-cancer therapy is associated with long-term epigenomic changes in childhood cancer survivors

BACKGROUND

Childhood cancer survivors (CCS) exhibit significantly increased chronic diseases and premature death. Abnormalities in DNA methylation are associated with development of chronic diseases and reduced life expectancy. We investigated the hypothesis that anti-cancer treatments are associated with long-term DNA methylation changes that could be key drivers of adverse late health effects.

METHODS

Genome-wide DNA methylation was assessed using MethylationEPIC arrays in paired samples (before/after therapy) from 32 childhood cancer patients. Separately, methylation was determined in 32 samples from different adult CCS (mean 22-years post-diagnosis) and compared with cancer-free controls (n = 284).

RESULTS

Widespread DNA methylation changes were identified post-treatment in childhood cancer patients, including 146 differentially methylated regions (DMRs), which were consistently altered in the 32 post-treatment samples. Analysis of adult CCS identified matching methylation changes at 107/146 of the DMRs, suggesting potential long-term retention of post-therapy changes. Adult survivors also exhibited epigenetic age acceleration, independent of DMR methylation. Furthermore, altered methylation at the DUSP6 DMR was significantly associated with early mortality, suggesting altered methylation may be prognostic for some late adverse health effects in CCS.

CONCLUSIONS

These novel methylation changes could serve as biomarkers for assessing normal cell toxicity in ongoing treatments and predicting long-term health outcomes in CCS.

The Advances in Epigenetics for Cancer Radiotherapy

Cancer is an important factor threatening human life and health; in recent years, its morbidity and mortality remain high and demosntrate an upward trend. It is of great significance to study its pathogenesis and targeted therapy. As the complex mechanisms of epigenetic modification has been increasingly discovered, they are more closely related to the occurrence and development of cancer. As a reversible response, epigenetic modification is of great significance for the improvement of classical therapeutic measures and the discovery of new therapeutic targets. It has become a research focusto explore the multi-level mechanisms of RNA, DNA, chromatin and proteins. As an important means of cancer treatment, radiotherapy has made great progress in technology, methods, means and targeted sensitization after years of rapid development, and even research on radiotherapy based on epigenetic modification is rampant. A series of epigenetic effects of radiation on DNA methylation, histone modification, chromosome remodeling, RNA modification and non-coding RNA during radiotherapy affects the therapeutic effects and prognosis. Starting from the epigenetic mechanism of tumorigenesis, this paper reviews the latest progress in the mechanism of interaction between epigenetic modification and cancer radiotherapy and briefly introduces the main types, mechanisms and applications of epigenetic modifiers used for radiotherapy sensitization in order to explore a more individual and dynamic approach of cancer treatment based on epigenetic mechanism. This study strives to make a modest contribution to the progress of human disease research.

In vitro relationships of galactic cosmic radiation and epigenetic clocks in human bronchial epithelial cells

Ionizing radiation is a well-appreciated health risk, precipitant of DNA damage, and contributor to DNA methylation variability. Nevertheless, relationships of ionizing radiation with DNA methylation-based markers of biological age (i.e. epigenetic clocks) remain poorly understood. Using existing data from human bronchial epithelial cells, we examined in vitro relationships of three epigenetic clock measures (Horvath DNAmAge, MiAge, and epiTOC2) with galactic cosmic radiation (GCR), which is particularly hazardous due to its high linear energy transfer (LET) heavy-ion components. High-LET 56Fe was significantly associated with accelerations in epiTOC2 (β = 192 cell divisions, 95% CI: 71, 313, p-value = .003). We also observed a significant, positive interaction of 56Fe ions and time-in-culture with epiTOC2 (95% CI: 42, 441, p-value = .019). However, only the direct 56Fe ion association remained statistically significant after adjusting for multiple hypothesis testing. Epigenetic clocks were not significantly associated with high-LET 28Si and low-LET X-rays. Our results demonstrate sensitivities of specific epigenetic clock measures to certain forms of GCR. These findings suggest that epigenetic clocks may have some utility for monitoring and better understanding the health impacts of GCR.

Genome-wide association studies identify novel genetic loci for epigenetic age acceleration among survivors of childhood cancer

Background

Increased epigenetic age acceleration (EAA) in survivors of childhood cancer is associated with specific treatment exposures, unfavorable health behaviors, and presence of certain chronic health conditions. To better understand inter-individual variability, we investigated the genetic basis underlying EAA.

Methods

Genome-wide association studies of EAA based on multiple epigenetic clocks (Hannum, Horvath, PhenoAge, and GrimAge) were performed. MethylationEPIC BeadChip array and whole-genome sequencing data were generated with blood-derived DNA from participants in the St. Jude Lifetime Cohort Study (discovery: 2138 pre-existing and 502 newly generated data, all survivors; exploratory: 282 community controls). Linear regression models were fit for each epigenetic age against the allelic dose of each genetic variant, adjusting for age at sampling, sex, and cancer treatment exposures. Fixed-effects meta-analysis was used to combine summary statistics from two discovery data sets. LD (Linkage disequilibrium) score regression was used to estimate single-nucleotide polymorphism (SNP)-based heritability.

Results

For EAA-Horvath, a genome-wide significant association was mapped to the SELP gene with the strongest SNP rs732314 (meta-GWAS: β=0.57, P=3.30×10^-11). Moreover, the stratified analysis of the association between rs732314 and EAA-Horvath showed a substantial heterogeneity between children and adults (meta-GWAS: β=0.97 vs. 0.51, I²=73.1%) as well as between survivors with and without chest/abdominal/pelvic-RT exposure (β=0.64 vs. 0.31, I²=66.3%). For EAA-Hannum, an association was mapped to the HLA locus with the strongest SNP rs28366133 (meta-GWAS: β=0.78, P=3.78×10^-11). There was no genome-wide significant hit for EAA-PhenoAge or EAA-GrimAge. Interestingly, among community controls, rs732314 was associated with EAA-Horvath (β=1.09, P=5.43×10^-5), whereas rs28366133 was not associated with EAA-Hannum (β=0.21, P=0.49). The estimated heritability was 0.33 (SE=0.20) for EAA-Horvath and 0.17 (SE=0.23) for EAA-Hannum, but close to zero for EAA-PhenoAge and EAA-GrimAge.

Conclusions

We identified novel genetic variants in the SELP gene and HLA region associated with EAA-Horvath and EAA-Hannum, respectively, among survivors of childhood cancer. The new genetic variants in combination with other replicated known variants can facilitate the identification of survivors at higher risk in developing accelerated aging and potentially inform drug targets for future intervention strategies among vulnerable survivors.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13073-022-01038-6.

Low-grade inflammation in survivors of childhood cancer and testicular cancer and its association with hypogonadism and metabolic risk factors

Background

In childhood (CCS) and testicular cancer (TCS) survivors, low-grade inflammation may represent a link between testosterone deficiency (hypogonadism) and risk of metabolic syndrome. We aimed to study levels of inflammatory markers in CCS and TCS and the association with hypogonadism and future cardio-metabolic risk factors.

Methods

Serum levels of inflammatory markers and testosterone were analyzed in CCS (n = 90), and TCS (n = 64, median time from diagnosis: 20 and 2.0 years, respectively), and in controls (n = 44). Differences in levels between patients and controls were calculated using univariate analysis of variance. T-test and logistic regression were applied to compare levels of cardio-metabolic risk factors and odds ratio (OR) of hypogonadism and metabolic syndrome in low and high inflammatory marker groups after 4–12 years of follow up. Adjustment for age, smoking, and active cancer was made.

Results

TCS and CCS, as compared to controls, had 1.44 (95%CI 1.06–1.96) and 1.25 (95 CI 1.02–1.53) times higher levels of IL-8, respectively. High IL-6 levels were associated with hypogonadism at baseline (OR 2.83, 95%CI 1.25–6.43) and the association was stronger for high IL-6 combined with low IL-10 levels (OR 3.10, 95%CI 1.37–7.01). High IL-6 levels were also associated with higher BMI, waist circumference, insulin, and HbA1c at follow up. High TNF-α was associated with higher diastolic blood pressure. No individual inflammatory marker was significantly associated with risk of metabolic syndrome at follow up. High IL-6 combined with low IL-10 levels were associated with risk of metabolic syndrome (OR 3.83, 95%CI 1.07–13.75), however not statistically significantly after adjustment.

Conclusion

TCS and CCS present with low-grade inflammation. High IL-6 levels were associated with hypogonadism and cardio-metabolic risk factors. Low IL-10 levels might reinforce the IL-6 mediated risk of developing metabolic syndrome.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-09253-5.

Commonalities in the Features of Cancer and Chronic Fatigue Syndrome (CFS): Evidence for Stress-Induced Phenotype Instability?

Chronic Fatigue Syndrome/Myalgic Encephalomyelitis (CFS/ME) and Cancer-Related Fatigue (CRF) are syndromes with considerable overlap with respect to symptoms. There have been many studies that have compared the two conditions, and some of this research suggests that the etiologies of the conditions are linked in some cases. In this narrative review, CFS/ME and cancer are introduced, along with their known and putative mechanistic connections to multiple stressors including ionizing radiation. Next, we summarize findings from the literature that suggest the involvement of HPA-axis dysfunction, the serotonergic system, cytokines and inflammation, metabolic insufficiency and mitochondrial dysfunction, and genetic changes in CRF and CFS/ME. We further suspect that the manifestation of fatigue in both diseases and its causes could indicate that CRF and CFS/ME lie on a continuum of potential biological effects which occur in response to stress. The response to this stress likely varies depending on predisposing factors such as genetic background. Finally, future research ideas are suggested with a focus on determining if common biomarkers exist in CFS/ME patients and those afflicted with CRF. Both CFS/ME and CRF are relatively heterogenous syndromes, however, it is our hope that this review assists in future research attempting to elucidate the commonalities between CRF and CFS/ME.

Possible Mechanisms of Subsequent Neoplasia Development in Childhood Cancer Survivors: A Review

Advances in medicine have improved outcomes in children diagnosed with cancer, with overall 5-year survival rates for these children now exceeding 80%. Two-thirds of childhood cancer survivors have at least one late effect of cancer therapy, with one-third having serious or even life-threatening effects. One of the most serious late effects is a development of subsequent malignant neoplasms (histologically different cancers, which appear after the treatment for primary cancer), which occur in about 3-10% of survivors and are associated with high mortality. In cancers with a very good prognosis, subsequent malignant neoplasms significantly affect long-term survival. Therefore, there is an effort to reduce particularly hazardous treatments. This review discusses the importance of individual factors (gender, genetic factors, cytostatic drugs, radiotherapy) in the development of subsequent malignant neoplasms and the possibilities of their prediction and prevention in the future.

Biological Aspects of Inflamm-Aging in Childhood Cancer Survivors

Anti-cancer treatments improve survival in children with cancer. A total of 80% of children treated for childhood cancer achieve 5-year survival, becoming long-term survivors. However, they undergo several chronic late effects related to treatments. In childhood cancer survivors a chronic low-grade inflammation, known as inflamm-aging, is responsible for frailty, a condition characterized by vital organ failure and by premature aging processes. Inflamm-aging is closely related to chemotherapy and radiotherapy, which induce inflammation, accumulation of senescent cells, DNA mutations, and the production of reactive oxygen species. All these conditions are responsible for the onset of secondary diseases, such as osteoporosis, cardiovascular diseases, obesity, and infertility. Considering that the pathobiology of frailty among childhood cancer survivors is still unknown, investigations are needed to better understand frailty's biological and molecular processes and to identify inflamm-aging key biomarkers in order to facilitate the screening of comorbidities and to clarify whether treatments, normally used to modulate inflamm-aging, may be beneficial. This review offers an overview of the possible biological mechanisms involved in the development of inflamm-aging, focusing our attention on immune system alteration, oxidative stress, cellular senescence, and therapeutic strategies.

Is early life adversity a trigger towards inflammageing?

There are many 'faces' of early life adversity (ELA), such as childhood trauma, institutionalisation, abuse or exposure to environmental toxins. These have been implicated in the onset and severity of a wide range of chronic non-communicable diseases later in life. The later-life disease risk has a well-established immunological component. This raises the question as to whether accelerated immune-ageing mechanistically links early-life adversity to the lifelong health trajectory resulting in either 'poor' or 'healthy' ageing. Here we examine observational and mechanistic studies of ELA and inflammageing, highlighting common and distinct features in these two life stages. Many biological processes appear in common including reduction in telomere length, increased immunosenescence, metabolic distortions and chronic (viral) infections. We propose that ELA shapes the developing immune, endocrine and nervous system in a non-reversible way, creating a distinct phenotype with accelerated immunosenescence and systemic inflammation. We conclude that ELA might act as an accelerator for inflammageing and age-related diseases. Furthermore, we now have the tools and cohorts to be able to dissect the interaction between ELA and later life phenotype. This should, in the near future, allow us to identify the ecological and mechanistic processes that are involved in 'healthy' or accelerated immune-ageing.

Low-grade chronic inflammation and immune alterations in childhood and adolescent cancer survivors: A contribution to accelerated aging?

BACKGROUND

The long-term consequences of chemotherapy and radiotherapy result in a high prevalence and early onset of age-related chronic diseases in survivors. We aimed to examine whether childhood and adolescent cancer survivors (CS) demonstrate biomarkers of accelerated aging.

METHODS

We evaluated 50 young adult CS at 11 [8-15] years after cancer diagnosis, and 30 healthy, age and sex-matched controls, who were unexposed to cancer therapy. Using a machine-learning approach, we assessed factors discriminating CS from controls and compared selected biomarkers and lymphocyte subpopulations with data from the Framingham Heart Study (FHS) cohort and the Genotype Tissue Expression (GTEx) project.

RESULTS

Survivors compared with controls had higher levels of C-reactive protein and fibrinogen. The surface expression of CD38 on T cells was increased, and there was an increase in the percentage of memory T cells in survivors, compared with the unexposed group. The relationships between above cell subpopulations and age were consistent in CS, FHS, and GTEx cohorts, but not in controls.

CONCLUSIONS

Young pediatric cancer survivors differ from age-related controls in terms of activation of the adaptive immune system and chronic, low-grade inflammation. These changes resemble aging phenotype observed in older population. Further research in biomarkers of aging in young, adult childhood cancer survivors is warranted, as it may facilitate screening and prevention of comorbidities in this population.

Chromatin accessibility of circulating CD8+ T cells predicts treatment response to PD-1 blockade in patients with gastric cancer

Although tumor genomic profiling has identified small subsets of gastric cancer (GC) patients with clinical benefit from anti-PD-1 treatment, not all responses can be explained by tumor sequencing alone. We investigate epigenetic elements responsible for the differential response to anti-PD-1 therapy by quantitatively assessing the genome-wide chromatin accessibility of circulating CD8⁺ T cells in patients’ peripheral blood. Using an assay for transposase-accessible chromatin using sequencing (ATAC-seq), we identify unique open regions of chromatin that significantly distinguish anti-PD-1 therapy responders from non-responders. GC patients with high chromatin openness of circulating CD8⁺ T cells are significantly enriched in the responder group. Concordantly, patients with high chromatin openness at specific genomic positions of their circulating CD8⁺ T cells demonstrate significantly better survival than those with closed chromatin. Here we reveal that epigenetic characteristics of baseline CD8⁺ T cells can be used to identify metastatic GC patients who may benefit from anti-PD-1 therapy.

Anti-PD-1 therapy could induce a durable response in patients with gastric cancer, however biomarkers to predict response to immunotherapy are generally lacking. Here the authors report that openness of chromatin in circulating CD8⁺ T cells predicts treatment outcome in patients with metastatic gastric cancer treated with pembrolizumab.

Intestinal Dysbiosis and Development of Cardiometabolic Disorders in Childhood Cancer Survivors: A Critical Review

Significance: Survivors of pediatric cancers have a high risk of developing side effects after the end of their treatments. Many potential factors have been associated with the onset of cardiometabolic disorders (CMD), including cancer disease itself, chemotherapy, hormonal treatment, radiotherapy, and genetics. However, the precise etiology and underlying mechanisms of these long-term complications are poorly understood. Recent Advances: Greater awareness is currently paid to the role of microbiota in the emergence of cancers and modulation of cancer therapies in both children and adults. Alterations in the composition and diversity of intestinal microbiota can clearly influence tumor development and progression as well as immune responses and clinical output. As dysbiosis is closely linked to the development of host metabolic diseases, including obesity, metabolic syndrome, type 2 diabetes, and non-alcoholic fatty liver disease, it may increase the risk of CMD in cancer populations. Critical Issues: Only limited studies targeting the profile of intestinal dysbiosis before and after cancer treatment have been conducted. Further, the exact contribution of intestinal dysbiosis to the development of CMD in cancer survivors is poorly appreciated. This review intends to clarify the influence of gut microbiota on CMD in childhood cancer survivors, elucidate the potential mechanisms, and evaluate the latest research on the interplay between diet/food supplement, microbiota, and cancer-related CMD. Future Directions: The implication of intestinal dysbiosis in late metabolic complications of childhood cancer survivors should be clarified. Intervention strategies could be developed to reduce the risk of survivors to CMD. Antioxid. Redox Signal. 34, 223-251.

Immunosenescence in Testicular Cancer Survivors: Potential Implications of Cancer Therapies and Psychological Distress

Testicular cancer (TC) is the most frequent solid tumor diagnosed in young adult males. Although it is a curable tumor, it is frequently associated with considerable short-term and long-term morbidity. Both biological and psychological stress experienced during cancer therapy may be responsible for stimulating molecular processes that induce premature aging and deterioration of immune system (immunosenescence) in TC survivors, leading to an increased susceptibility to infections, cancer, and autoimmune diseases. Immunosenescence is a remodeling of immune cell populations with inversion of the CD4:CD8 ratio, accumulation of highly differentiated memory cells, shrinkage of telomeres, shift of T-cell response to Th2 type, and release of pro-inflammatory signals. TC survivors exposed to chemotherapy show features of immunological aging, including an increase in memory T-cells (CD4+ and CD8+) and high expression of the senescence biomarker p16INK4a in CD3+ lymphocytes. However, the plethora of factors involved in the premature aging of TC survivors make the situation more complex if we also take into account the psychological stress and hormonal changes experienced by patients, as well as the high-dose chemotherapy and hematopoietic stem cell transplantation that some individuals may be required to undergo. The relatively young age and the long life expectancy of TC patients bear witness to the importance of improving quality of life and of alleviating long-term side-effects of cancer treatments. Within this context, the present review takes an in-depth look at the molecular mechanisms of immunosenescence, describing experimental evidence of cancer survivor aging and highlighting the interconnected relationship between the many factors modulating the aging of the immune system of TC survivors.

Ionizing radiation-induced circulatory and metabolic diseases

Risks to health are the prime consideration in all human situations of ionizing radiation exposure and therefore of relevance to radiation protection in all occupational, medical, and public exposure situations. Over the past few decades, advances in therapeutic strategies have led to significant improvements in cancer survival rates. However, a wide range of long-term complications have been reported in cancer survivors, in particular circulatory diseases and their major risk factors, metabolic diseases. However, at lower levels of exposure, the evidence is less clear. Under real-life exposure scenarios, including radiotherapy, radiation effects in the whole organism will be determined mainly by the response of normal tissues receiving relatively low doses, and will be mediated and moderated by systemic effects. Therefore, there is an urgent need for further research on the impact of low-dose radiation. In this article, we review radiation-associated risks of circulatory and metabolic diseases in clinical, occupational or environmental exposure situations, addressing epidemiological, biological, risk modelling, and systems biology aspects, highlight the gaps in knowledge and discuss future directions to address these gaps.

The Human Blood Transcriptome in a Large Population Cohort and Its Relation to Aging and Health

Background: The blood transcriptome is expected to provide a detailed picture of an organism's physiological state with potential outcomes for applications in medical diagnostics and molecular and epidemiological research. We here present the analysis of blood specimens of 3,388 adult individuals, together with phenotype characteristics such as disease history, medication status, lifestyle factors, and body mass index (BMI). The size and heterogeneity of this data challenges analytics in terms of dimension reduction, knowledge mining, feature extraction, and data integration.

Methods: Self-organizing maps (SOM)-machine learning was applied to study transcriptional states on a population-wide scale. This method permits a detailed description and visualization of the molecular heterogeneity of transcriptomes and of their association with different phenotypic features.

Results: The diversity of transcriptomes is described by personalized SOM-portraits, which specify the samples in terms of modules of co-expressed genes of different functional context. We identified two major blood transcriptome types where type 1 was found more in men, the elderly, and overweight people and it upregulated genes associated with inflammation and increased heme metabolism, while type 2 was predominantly found in women, younger, and normal weight participants and it was associated with activated immune responses, transcriptional, ribosomal, mitochondrial, and telomere-maintenance cell-functions. We find a striking overlap of signatures shared by multiple diseases, aging, and obesity driven by an underlying common pattern, which was associated with the immune response and the increase of inflammatory processes.

Conclusions: Machine learning applications for large and heterogeneous omics data provide a holistic view on the diversity of the human blood transcriptome. It provides a tool for comparative analyses of transcriptional signatures and of associated phenotypes in population studies and medical applications.

Frailty and aging in cancer survivors

There are over 15 million survivors of cancer in the United States whose rates of frailty, an aging phenotype, range from just under 10% to over 80%. Frailty impacts not only disease survival but also long-term function and quality of life in children, adolescents, and in all adults diagnosed and/or treated for cancer. This review explains frailty as a construct and model of physiologic well-being. It also describes how frailty at diagnosis impacts cancer outcomes in adult populations and enumerates the prevalence of frailty in different populations of cancer survivors. Biological mechanisms responsible for aging and potentially for frailty among individuals with or who have been treated for cancer are discussed. Finally, promising pharmaceutical and lifestyle interventions designed to impact aging rather than a specific disease, tested in other populations, but likely applicable in cancer patients and survivors, are discussed.

Epigenetic changes during ageing and their underlying mechanisms

As life expectancy increases worldwide, ageing and age-related diseases arise as a major issue for societies around the globe. Understanding the biological mechanisms underlying the ageing process is thus instrumental for the development of efficient interventions aimed to prevent and treat age-related conditions. Current knowledge in the biogerontology field points to epigenetics as a critical component of the ageing process, not only by serving as a bona-fide marker of biological age but also by controlling and conferring inheritability to cellular and organismal ageing. This is reflected by a myriad of evidences demonstrating the relationship between DNA methylation, histone modifications, chromatin remodeling and small non-coding RNAs and several age-related phenotypes. Given the reversibility of epigenetic alterations, epigenetic reprogramming may also be envisioned as a potential approach to treat age-related disorders. Here we review how different types of epigenetic mechanisms are involved in the ageing process. In addition, we highlight how interventions modulate epigenetics and thus promote health- and lifespan.

Irradiation impairs mitochondrial function and skeletal muscle oxidative capacity: significance for metabolic complications in cancer survivors

BACKGROUND

Metabolic complications are highly prevalent in cancer survivors treated with irradiation but the underlying mechanisms remain unknown.

METHODS

Chow or high fat-fed C57Bl/6J mice were irradiated (6Gy) before investigating the impact on whole-body or skeletal muscle metabolism and profiling their lipidomic signature. Using a transgenic mouse model (Tg:Pax7-nGFP), we isolated muscle progenitor cells (satellite cells) and characterised their metabolic functions. We recruited childhood cancer survivors, grouped them based on the use of total body irradiation during their treatment and established their lipidomic profile.

RESULTS

In mice, irradiation delayed body weight gain and impaired fat pads and muscle weights. These changes were associated with impaired whole-body fat oxidation in chow-fed mice and altered ex vivo skeletal muscle fatty acid oxidation, potentially due to a reduction in oxidative fibres and reduced mitochondrial enzyme activity. Irradiation led to fasting hyperglycaemia and impaired glucose uptake in isolated skeletal muscles. Cultured satellite cells from irradiated mice showed decreased fatty acid oxidation and reduced glucose uptake, recapitulating the host metabolic phenotype. Irradiation resulted in a remodelling of lipid species in skeletal muscles, with the extensor digitorum longus muscle being particularly affected. A large number of lipid species were reduced, with several of these species showing a positive correlation with mitochondrial enzymes activity. In cancer survivors exposed to irradiation, we found a similar decrease in systemic levels of most lipid species, and lipid species that increased were positively correlated with insulin resistance (HOMA-IR).

CONCLUSION

Irradiation leads to long-term alterations in body composition, and lipid and carbohydrate metabolism in skeletal muscle, and affects muscle progenitor cells. Such changes result in persistent impairment of metabolic functions, providing a new mechanism for the increased prevalence of metabolic diseases reported in irradiated individuals. In this context, changes in the lipidomic signature in response to irradiation could be of diagnostic value.