Chemically induced carcinogenesis in rodent models of aging: assessing organismal resilience to genotoxic stressors in geroscience research

Tumor-derived extracellular vesicle proteins as new biomarkers and targets in precision oncology

Extracellular vesicles (EVs) are important carriers of signaling molecules, such as nucleic acids, proteins, and lipids, and have become a focus of increasing interest due to their numerous physiological and pathological functions. For a long time, most studies on EV components focused on noncoding RNAs; however, in recent years, extracellular vesicle proteins (EVPs) have been found to play important roles in diagnosis, treatment, and drug resistance and thus have been considered favorable biomarkers and therapeutic targets for various tumors. In this review, we describe the general protocols of research on EVPs and summarize their multifaceted roles in precision medicine applications, including cancer diagnosis, dynamic monitoring of therapeutic efficacy, drug resistance research, tumor microenvironment interaction research, and anticancer drug delivery.

CD112 is an epithelial-to-mesenchymal transition-related and immunological biomarker in pan-cancer

Background

The nectin adhesion molecule CD112, an important component of tumor progression, belongs to the nectin family. However, a comprehensive evaluation of its clinical relevance and mechanism in various cancers is yet to be conducted.

Methods

This investigation fully examined the relationship between prognosis and CD112 expression. We clarified the function of CD112 in tumor immunity by employing The Cancer Genome Atlas (TCGA) and Genotype-Tissue Expression (GTEx) databases. This involved examining its connections to tumor mutation burden (TMB), DNA methylation, tumor immune invasion, mismatch repair (MMR), microsatellite instability (MSI), and common immune checkpoint inhibitors (ICIs). Additionally, the impact of CD112 knockdown on cell function was examined in colorectal cancer (CRC) cell lines.

Results

In the current study, we found malignant tissues express high levels of CD112, which was related to TMB, MMR, MSI, and DNA methylation. Survival analysis indicated that patients with high CD112 expression had an unfavorable prognosis more frequently. In addition, CD112 expression was negatively associated with infiltration levels of CD4 positive (CD4+) T cells, CD8 positive (CD8+) T cells, and T cells. Western blotting and pathway enrichment analysis showed that CD112 is significantly linked to epithelial-to-mesenchymal transition (EMT). Additionally, CRC cells migrate and proliferate less when CD112 was knocked down. CD112 expression was found to be negatively associated with anti-programmed cell death protein 1 (PD-1) and anti-cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) treatment outcomes in patients.

Conclusions

CD112 may act as a possible prognostic marker in immune therapy and may stimulate tumor growth by upregulating the EMT pathway.

Extracellular vesicles in cancer therapy: Roles, potential application, and challenges

Extracellular vesicles (EVs) have emerged as a novel cell-free strategy for the treatment of many diseases including cancer as they play important roles in cancer development and progression. Considering their natural capacity to facilitate cell-to-cell communication as well as their high physiochemical stability and biocompatibility, EVs serve as superior delivery systems for a wide range of therapeutic agents, including medicines, nanomaterials, nucleic acids, and proteins. Therefore, EVs-based cancer therapy is of greater interest to researchers. Mounting studies indicate that EVs can be improved in efficiency, specificity, and safety for cancer therapy. However, their heterogeneity of physicochemical properties and functions is not fully understood, hindering the achievement of bioactive EVs with high yield and purity. Herein, we paid more attention to the EVs applications and their significance in cancer therapy.

Endothelial deficiency of insulin-like growth factor-1 receptor leads to blood-brain barrier disruption and accelerated endothelial senescence in mice, mimicking aspects of the brain aging phenotype

INTRODUCTION

Age-related blood-brain barrier (BBB) disruption, cerebromicrovascular senescence, and microvascular rarefaction substantially contribute to the pathogenesis of vascular cognitive impairment (VCI) and Alzheimer's disease (AD). Previous studies established a causal link between age-related decline in circulating levels of insulin-like growth factor-1 (IGF-1), cerebromicrovascular dysfunction, and cognitive decline. The aim of our study was to determine the effect of IGF-1 signaling on senescence, BBB permeability, and vascular density in middle-age and old brains.

METHODS

Accelerated endothelial senescence was assessed in senescence reporter mice (VE-Cadherin-CreERT2 /Igf1rfl/fl × p16-3MR) using flow cytometry. To determine the functional consequences of impaired IGF-1 input to cerebromicrovascular endothelial cells, BBB integrity and capillary density were studied in mice with endothelium-specific knockout of IGF1R (VE-Cadherin-CreERT2 /Igf1rfl/fl ) using intravital two-photon microscopy.

RESULTS

In VE-Cadherin-CreERT2 /Igf1rfl/fl mice: (1) there was an increased presence of senescent endothelial cells; (2) cumulative permeability of the microvessels to fluorescent tracers of different molecular weights (0.3-40 kDa) is significantly increased, as compared to that of control mice, whereas decline in cortical capillary density does not reach statistical significance.

CONCLUSIONS

These findings support the notion that IGF-1 signaling plays a crucial role in preserving a youthful cerebromicrovascular endothelial phenotype and maintaining the integrity of the BBB.

Multiple myeloma, a quintessential malignant disease of aging: a geroscience perspective on pathogenesis and treatment

Multiple myeloma (MM) is an incurable plasma cell malignancy, which is predominantly a disease of older adults (the median age at diagnosis is 70 years). The slow progression from asymptomatic stages and the late-onset of MM suggest fundamental differences compared to many other hematopoietic system-related malignancies. The concept discussed in this review is that age-related changes at the level of terminally differentiated plasma cells act as the main risk factors for the development of MM. Epigenetic and genetic changes that characterize both MM development and normal aging are highlighted. The relationships between cellular aging processes, genetic mosaicism in plasma cells, and risk for MM and the stochastic processes contributing to clonal selection and expansion of mutated plasma cells are investigated. In line with the DNA damage accumulation theory of aging, in this review, the evolution of monoclonal gammopathy to symptomatic MM is considered. Therapeutic consequences of age-dependent comorbidities that lead to frailty and have fundamental influence on treatment outcome are described. The importance of considering geriatric states when planning the life-long treatment course of an elderly MM patient in order to achieve maximal therapeutic benefit is emphasized.

Urbanity as a source of genotoxicity in the synanthropic Kelp Gull (Larus dominicanus)

Increases in human population lead to an increase in urban wastes, which could affect wildlife in several ways. Urban pollutants can affect erythrocytes of birds generating morphological membrane and nuclear anomalies. The Kelp Gull (Larus dominicanus) is an opportunistic species, which take advantage of urban environments, thus being highly exposed to environmental pollution. In northeastern Patagonia, the dynamic of the waste management was transformed in the last decade and consequently, gulls changed their movements in response to changes in waste management systems. The food available to the seagulls went from being a mixture of urban/fishing discards until 2015, when this landfill closures, to being domestic urban offerings. In order of evaluating genotoxicity and changes in pollutants exposition due to these changes, we analyzed the frequencies of erythrocytes nuclear abnormalities and micronuclei (ENAs and MN respectively) in 58 blood smears from adults extracted during the non-breeding season in two periods in landfills with different waste compositions: a mixed landfill (ML) in 2013 before closure (n = 24) versus an urban landfill (UL) (n = 34) in 2021. We found that the Kelp Gull showed high values of abnormalities with an average of 151.5 /10,000 RBC in comparison with other seabird species. The bud and notched types of ENAs were the most prevalent abnormalities in both sites. We did not find significate differences in the overall abnormality frequency between sites, however we found significant higher frequencies in displaced and tailed types of ENAs in ML. We also found poikilocytosis, as seen previously in other animals exposed experimentally to pollutants such as metals and crude oil. Cellular abnormalities found in the Kelp Gull suggest an exposition of individuals to pollutants in foraging areas. The hemispheric distribution and the synanthropic characteristics of the species denote its importance as a suitable global monitor of genotoxicity.

The pro-proliferative effect of insulin in human breast epithelial DMBA-transformed and non-transformed cell lines is PI3K-, mTOR- and GLUT1-dependent

Type 2 diabetes mellitus (T2DM) is linked to an increased risk of breast cancer. We aimed to investigate how T2DM-associated characteristics (high levels of glucose, insulin, leptin, inflammatory mediators and oxidative stress) influence breast cancer carcinogenesis, in DMBA-treated (MCF-12A_DMBA ) and non-treated breast epithelial (MCF-12A) cell lines. Insulin (50 nM) promotes cell proliferation, ³ H-DG uptake and lactic acid production in both cell lines. The stimulatory effects of insulin upon cell proliferation and ³ H-DG uptake were hampered by rapamycin, LY294001 and BAY-876, in both cell lines. In conclusion, hyperinsulinemia, one important characteristic of T2DM, contributes to the initiation of breast cancer by a PI3K- and mTOR-dependent mechanism involving increased GLUT1-mediated glucose uptake. SIGNIFICANCE: The pro-proliferative effect of insulin in human breast epithelial DMBA-transformed and non-transformed cell lines is PI3K-, mTOR- and GLUT1-dependent.

The Immunomodulation Potential of Exosomes in Tumor Microenvironment

Exosomes are lipid bilayer particles that originated from almost all types of cells and play an important role in intercellular communication. Tumor-derived exosomes contain large amounts of noncoding RNA, DNA, and proteins, which can be transferred into recipient cells as functional components in exosomes. These exosomal functional constituents depend on the originating cells, and it has been proved that types and numbers of exosomal components differ in cancer patients and healthy individuals. This review summarizes the role of tumor-derived exosomes in immunomodulation and discusses the application of exosomes in immunotherapy in cancers. Overall, exosomes isolated from cancer cells are turned out to promote immune evasion and interfere with immune responses in tumors through inducing apoptosis of CD8+ T cells, facilitating generation of Tregs, suppressing natural killer (NK) cell cytotoxicity, inhibiting maturation and differentiation of monocyte, and enhancing suppressive function of myeloid-derived suppressor cells (MDSCs). Mechanistically, exosomal functional components play a significant role in the immunomodulation in cancers. Moreover, based on the existing studies, exosomes could potentially serve as therapeutic delivery vehicles, noninvasive biomarkers, and immunotherapeutic vaccines for various types of cancers.

Extra chromosomal DNA in different cancers: Individual genome with important biological functions

Cancer can be caused by various factors, including the malfunction of tumor suppressor genes and the hyper-activation of proto-oncogenes. Tumor-associated extrachromosomal circular DNA (eccDNA) has been shown to adversely affect human health and accelerate malignant actions. Whole-genome sequencing (WGS) on different cancer types suggested that the amplification of ecDNA has increased the oncogene copy number in various cancers. The unique structure and function of ecDNA, its profound significance in cancer, and its help in the comprehension of current cancer genome maps, renders it as a hotspot to explore the tumor pathogenesis and evolution. Illumination of the basic mechanisms of ecDNA may provide more insights into cancer therapeutics. Despite the recent advances, different features of ecDNA require further elucidation. In the present review, we primarily discussed the characteristics, biogenesis, genesis, and origin of ecDNA and later highlighted its functions in both tumorigenesis and therapeutic resistance of different cancers.

A Pan-Cancer Analysis of the Prognostic Value and Expression of Adenylate Cyclase 7 (ADCY7) in Human Tumors

BACKGROUND

The role of adenylate cyclase 7 (ADCY7) in cancer is still unclear. This study analyzed the interrelationship between the expression and immune function of ADCY7.

METHODS

ADCY7 expression in multiple human cancers was analyzed using the databases of Genotype-Tissue Expression Project (GTEx), Cancer Cell Line Encyclopedia (CCLE), and The Cancer Genome Atlas (TCGA). Correlations among ADCY7 gene expression, mismatch repair (MMR) gene expression, and DNA methyltransferase (DNMT) expression were assessed using Spearman correlation analysis. Univariate survival analysis and Kaplan-Meier (KM) curve were used to examine the effect of ADCY7 expression on prognosis. The Tumor Immune Estimation Resource (TIMER) database was used to evaluate the relationship between ADCY7 gene expression and tumor immune invasion or immune checkpoint gene (ICG) expression.

RESULTS

ADCY7 was abnormally expressed in multiple human cancers and was correlated with MMR genes and DNMT expression. Univariate survival analysis and KM curve showed that ADCY7 expression influences the overall survival (OS) of six types of cancer, disease-specific survival (DSS) of eight, and progression-free interval (PFI) of three. The high expression of ADCY7 in OS, DSS, and PFI was strongly associated with poor outcomes in patients with breast cancer and lung squamous cell carcinoma. ADCY7 expression was strongly associated with immune cell infiltration and ICG expression.

CONCLUSION

The results of this study indicated that ADCY7 may be a prognostic biomarker of tumorigenesis. The study may also provide a new perspective on the role of ADCY7 in human cancers.

A signature of tumor DNA repair genes associated with the prognosis of surgically-resected lung adenocarcinoma

Background

Lung cancer has the highest morbidity and mortality of cancers worldwide. Lung adenocarcinoma (LUAD) is the most common pathological subtype of lung cancer and surgery is its most common treatment. The dysregulated expression of DNA repair genes is found in a variety of cancers and has been shown to affect the origin and progression of these diseases. However, the function of DNA repair genes in surgically-treated LUAD is unclear.

Methods

We sought to determine the association between the signature of DNA repair genes for patients with surgical LUAD and their overall prognosis. We obtained gene expression data and corresponding clinical information of LUAD from The Cancer Genome Atlas (TCGA) database. The differently expressed DNA repair genes of surgically-treated LUAD and normal tissues were identified using the Wilcoxon rank-sum test. We used uni- and multivariate Cox regression analyses to shrink the aberrantly expressed genes, which were then used to construct the prognostic signature and the risk score formula associated with the independent prognosis of surgically-treated LUAD. We used Kaplan-Meier and Cox hazard ratio analyses to confirm the diagnostic and prognostic roles. Two validation sets (GSE31210 and GSE37745) were downloaded from the Gene Expression Omnibus (GEO) and were used to externally verify the prognostic value of the signature. OSluca online database verifies the hazard ratio for the DNA repair genes by which the signature was constructed. We investigated the correlation between the signature of the DNA repair genes and the clinical parameters. The potential molecular mechanisms and pathways of the prognostic signature were explored using Gene Set Enrichment Analysis (GSEA).

Results

We determined the prognostic signature based on six DNA repair genes (PLK1, FOXM1, PTTG1, CCNO, HIST3H2A, and BLM) and calculated the risk score based on this formula. Patients with surgically-treated LUAD were divided into high-risk and low-risk groups according to the median risk score. The high-risk group showed poorer overall survival than the low-risk group; the signature was used as an independent prognostic indicator and had a greater prognostic value in surgically-treated LUAD. The prognostic value was replicated in GSE31210 and GSE37745. OSluca online database analysis shows that six DNA repair genes were associated with poor prognosis in most lung cancer datasets. The prognostic signature risk score correlated with the pathological stage and smoking status in surgically-treated LUAD. The GSEA of the risk signature in high-risk patients showed pathways associated with the cell cycle, oocyte meiosis, mismatch repair, homologous recombination, and nucleotide excision repair.

Conclusions

A six-DNA repair gene signature was determined using TCGA data mining and GEO data verification. The gene signature may serve as a novel prognostic biomarker and therapeutic target for surgically-treated LUAD.

Exosome-based immunotherapy: a promising approach for cancer treatment

In the era of the rapid development of cancer immunotherapy, there is a high level of interest in the application of cell-released small vesicles that stimulate the immune system. As cell-derived nanovesicles, exosomes show great promise in cancer immunotherapy because of their immunogenicity and molecular transfer function. The cargoes carried on exosomes have been recently identified with improved technological advances and play functional roles in the regulation of immune responses. In particular, exosomes derived from tumor cells and immune cells exhibit unique composition profiles that are directly involved in anticancer immunotherapy. More importantly, exosomes can deliver their cargoes to targeted cells and thus influence the phenotype and immune-regulation functions of targeted cells. Accumulating evidence over the last decade has further revealed that exosomes can participate in multiple cellular processes contributing to cancer development and therapeutic effects, showing the dual characteristics of promoting and suppressing cancer. The potential of exosomes in the field of cancer immunotherapy is huge, and exosomes may become the most effective cancer vaccines, as well as targeted antigen/drug carriers. Understanding how exosomes can be utilized in immune therapy is important for controlling cancer progression; additionally, exosomes have implications for diagnostics and the development of novel therapeutic strategies. This review discusses the role of exosomes in immunotherapy as carriers to stimulate an anti-cancer immune response and as predictive markers for immune activation; furthermore, it summarizes the mechanism and clinical application prospects of exosome-based immunotherapy in human cancer.

BRCA1-Associated Protein Is a Potential Prognostic Biomarker and Is Correlated With Immune Infiltration in Liver Hepatocellular Carcinoma: A Pan-Cancer Analysis

Background

BRCA1-associated protein (BRAP) is a critical gene that regulates inflammation-related signaling pathway and affects patients’ prognosis in esophageal squamous cell carcinoma (ESCC). However, its roles in different cancers remain largely unknown.

Methods

BRAP expression in human pan-cancer was analyzed via the Genotype-Tissue Expression (GTEx) and The Cancer Genome Atlas (TCGA) database. Pearson correlation analysis was used to evaluate the association between BRAP expression with mismatch repair (MMR) gene mutation and DNA methyltransferase. We evaluated the influence of BRAP on clinical prognosis by univariate survival analysis. Moreover, the correlation between BRAP and tumor immune infiltration was analyzed via the Tumor Immune Evaluation Resource (TIMER) database. Pearson correlation analysis was used to investigate the correlation between BRAP expression and immune checkpoint genes expression.

Results

BRAP is abnormally overexpressed and significantly correlated with MMR gene mutation level and DNA methyltransferase expression in human pan-cancer. Univariate survival analysis showed that BRAP was significant with patients’ overall survival (OS) in six cancer types, disease-free interval (DFI) in three cancer types, and progression-free interval (PFI) in two cancer types. Remarkably, increased BRAP expression was strongly correlated with patients’ poor prognosis in liver hepatocellular carcinoma (LIHC), whether OS (P < 0.0001, hazard ratio (HR) = 1.1), DFI (P = 0.00099, HR = 1.06), or PFI (P = 0.00025, HR = 1.07). Moreover, a positive relationship was found between BRAP expression and immune infiltrating cells including B cell, CD4 + T cell, CD8 + T cell, dendritic cell, macrophage cell, and neutrophil cell in colon adenocarcinoma (COAD), kidney renal clear cell carcinoma (KIRC), and LIHC. Additionally, BRAP expression showed strong correlations with immune checkpoint genes in LIHC.

Conclusion

BRAP expression is increased in human pan-cancer samples compared with normal tissues. Overexpression of BRAP is correlated with poor prognosis and immune infiltration in multiple cancers, especially in LIHC. These findings suggest that BRAP may be used as a potential molecular biomarker for determining prognosis and immune infiltration in LIHC.

Dimethylbenz(a)anthracene-induced mammary tumorigenesis in mice

Every year, over 2 million women are diagnosed with breast cancer. Although considerable progress was made within the last years in cancer prevention, diagnosis and treatment, breast cancer is still responsible for over 600,000 of deaths per year. Over the years, numerous mouse models have been developed to understand breast cancer etiology and progression. Among those, mammary carcinomas induced by carcinogen, such as 7,12-dimethylbenz[a]anthracene (DMBA), has been widely used. Generally, 30-70% of mice exposed to 4-6 weekly doses of 1mg of DMBA during the peripubertal period (4-10 weeks of age) will develop mammary tumors within 150-200 days after the first exposure, that sometime metastasize to the lungs. As a result, DMBA-induced tumorigenesis is thought to be an accurate and relevant model to study breast cancer as it closely mimics this multistep process. This chapter presents the typical protocol used in mice to induce mammary gland tumors using DMBA. The influence of the number of doses and the total burden of DMBA given, as well as of the age and strain of the mice on mammary gland incident and on tumor onset are discussed. The current knowledge regarding mechanisms involved in DMBA-induced tumorigenesis is also presented.

Current understanding of extrachromosomal circular DNA in cancer pathogenesis and therapeutic resistance

Extrachromosomal circular DNA was recently found to be particularly abundant in multiple human cancer cells, although its frequency varies among different tumor types. Elevated levels of extrachromosomal circular DNA have been considered an effective biomarker of cancer pathogenesis. Multiple reports have demonstrated that the amplification of oncogenes and therapeutic resistance genes located on extrachromosomal DNA is a frequent event that drives intratumoral genetic heterogeneity and provides a potential evolutionary advantage. This review highlights the current understanding of the extrachromosomal circular DNA present in the tissues and circulation of patients with advanced cancers and provides a detailed discussion of their substantial roles in tumor regulation. Confirming the presence of cancer-related extrachromosomal circular DNA would provide a putative testing strategy for the precision diagnosis and treatment of human malignancies in clinical practice.

Current perspectives on the clinical implications of oxidative RNA damage in aging research: challenges and opportunities

Ribonucleic acid (RNA) molecules can be easily attacked by reactive oxygen species (ROS), which are produced during normal cellular metabolism and under various oxidative stress conditions. Numerous findings report that the amount of cellular 8-oxoG, the most abundant RNA damage biomarker, is a promising target for the sensitive measurement of oxidative stress and aging-associated diseases, including neuropsychiatric disorders. Most importantly, available data suggest that RNA oxidation has important implications for various signaling pathways and gene expression regulation in aging-related diseases, highlighting the necessity of using combinations of RNA oxidation adducts in both experimental studies and clinical trials. In this review, we primarily describe evidence for the effect of oxidative stress on RNA integrity modulation and possible quality control systems. Additionally, we discuss the profiles and clinical implications of RNA oxidation products that have been under intensive investigation in several aging-associated medical disorders.