Clearance of senescent macrophages ameliorates tumorigenesis in KRAS-driven lung cancer

LPS-induced senescence of macrophages aggravates calcification and senescence of vascular smooth muscle cells via IFITM3

BACKGROUND

Cellular senescence, macrophages infiltration, and vascular smooth muscle cells (VSMCs) osteogenic transdifferentiation participate in the pathophysiology of vascular calcification in chronic kidney disease (CKD). Senescent macrophages are involved in the regulation of inflammation in pathological diseases. In addition, senescent cells spread senescence to neighboring cells via Interferon-induced transmembrane protein3 (IFITM3). However, the role of senescent macrophages and IFITM3 in VSMCs calcification remains unexplored.

AIMS

To explore the hypothesis that senescent macrophages contribute to the calcification and senescence of VSMCs via IFITM3.

METHODS

Here, the macrophage senescence model was established using Lipopolysaccharides (LPS). The VSMCs were subjected to supernatants from macrophages (MCFS) or LPS-induced macrophages (LPS-MCFS) in the presence or absence of calcifying media (CM). Senescence-associated β-galactosidase (SA-β-gal), Alizarin red (AR), immunofluorescent staining, and western blot were used to identify cell senescence and calcification.

RESULTS

The expression of IFITM3 was significantly increased in LPS-induced macrophages and the supernatants. The VSMCs transdifferentiated into osteogenic phenotype, expressing higher osteogenic differentiation markers (RUNX2) and lower VSMCs constructive makers (SM22α) when cultured with senescent macrophages supernatants. Also, senescence markers (p16 and p21) in VSMCs were significantly increased by senescent macrophages supernatants treated. However, IFITM3 knockdown inhibited this process.

CONCLUSIONS

Our study showed that LPS-induced senescence of macrophages accelerated the calcification of VSMCs via IFITM3. These data provide a new perspective linking VC and aging, which may provide clues for diagnosing and treating accelerated vascular aging in patients with CKD.

Regulation of cell function and identity by cellular senescence

During aging and in some contexts, like embryonic development, wound healing, and diseases such as cancer, senescent cells accumulate and play a key role in different pathophysiological functions. A long-held belief was that cellular senescence decreased normal cell functions, given the loss of proliferation of senescent cells. This view radically changed following the discovery of the senescence-associated secretory phenotype (SASP), factors released by senescent cells into their microenvironment. There is now accumulating evidence that cellular senescence also promotes gain-of-function effects by establishing, reinforcing, or changing cell identity, which can have a beneficial or deleterious impact on pathophysiology. These effects may involve both proliferation arrest and autocrine SASP production, although they largely remain to be defined. Here, we provide a historical overview of the first studies on senescence and an insight into emerging trends regarding the effects of senescence on cell identity.

Natural product/diet-based regulation of macrophage polarization: Implications in treatment of inflammatory-related diseases and cancer

Macrophages are phagocytic cells with important physiological functions, including the digestion of cellular debris, foreign substances, and microbes, as well as tissue development and homeostasis. The tumor microenvironment (TME) shapes the aggressiveness of cancer, and the biological and cellular interactions in this complicated space can determine carcinogenesis. TME can determine the progression, biological behavior, and therapy resistance of human cancers. The macrophages are among the most abundant cells in the TME, and their functions and secretions can determine tumor progression. The education of macrophages to M2 polarization can accelerate cancer progression, and therefore, the re-education and reprogramming of these cells is promising. Moreover, macrophages can cause inflammation in aggravating pathological events, including cardiovascular diseases, diabetes, and neurological disorders. The natural products are pleiotropic and broad-spectrum functional compounds that have been deployed as ideal alternatives to conventional drugs in the treatment of cancer. The biological and cellular interactions in the TME can be regulated by natural products, and for this purpose, they enhance the M1 polarization of macrophages, and in addition to inhibiting proliferation and invasion, they impair the chemoresistance. Moreover, since macrophages and changes in the molecular pathways in these cells can cause inflammation, the natural products impair the pro-inflammatory function of macrophages to prevent the pathogenesis and progression of diseases. Even a reduction in macrophage-mediated inflammation can prevent organ fibrosis. Therefore, natural product-mediated macrophage targeting can alleviate both cancerous and non-cancerous diseases.

Advances in circulating tumor cells for early detection, prognosis and metastasis reduction in lung cancer

Globally, lung cancer stands as the leading type of cancer in terms of incidence and is the major source of mortality attributed to cancer. We have outlined the molecular biomarkers for lung cancer that are available clinically. Circulating tumor cells (CTCs) spread from the original location, circulate in the bloodstream, extravasate, and metastasize, forming secondary tumors by invading and establishing a favorable environment. CTC analysis is considered a common liquid biopsy method for lung cancer. We have enumerated both in vivo and ex vivo techniques for CTC separation and enrichment, examined the advantages and limitations of these methods, and also discussed the detection of CTCs in other bodily fluids. We have evaluated the value of CTCs, as well as CTCs in conjunction with other biomarkers, for their utility in the early detection and prognostic assessment of patients with lung cancer. CTCs engage with diverse cells of the metastatic process, interfering with the interaction between CTCs and various cells in metastasis, potentially halting metastasis and enhancing patient prognosis.

Tumor initiation and early tumorigenesis: molecular mechanisms and interventional targets

Tumorigenesis is a multistep process, with oncogenic mutations in a normal cell conferring clonal advantage as the initial event. However, despite pervasive somatic mutations and clonal expansion in normal tissues, their transformation into cancer remains a rare event, indicating the presence of additional driver events for progression to an irreversible, highly heterogeneous, and invasive lesion. Recently, researchers are emphasizing the mechanisms of environmental tumor risk factors and epigenetic alterations that are profoundly influencing early clonal expansion and malignant evolution, independently of inducing mutations. Additionally, clonal evolution in tumorigenesis reflects a multifaceted interplay between cell-intrinsic identities and various cell-extrinsic factors that exert selective pressures to either restrain uncontrolled proliferation or allow specific clones to progress into tumors. However, the mechanisms by which driver events induce both intrinsic cellular competency and remodel environmental stress to facilitate malignant transformation are not fully understood. In this review, we summarize the genetic, epigenetic, and external driver events, and their effects on the co-evolution of the transformed cells and their ecosystem during tumor initiation and early malignant evolution. A deeper understanding of the earliest molecular events holds promise for translational applications, predicting individuals at high-risk of tumor and developing strategies to intercept malignant transformation.

β-Lapachone, an NQO1 bioactivatable drug, prevents lung tumorigenesis in mice

Lung cancer is one of the most lethal cancers with high incidence worldwide. The prevention of lung cancer is of great significance to reducing the social harm caused by this disease. An in-depth understanding of the molecular changes underlying precancerous lesions is essential for the targeted chemoprevention against lung cancer. Here, we discovered an increased NQO1 level over time within pulmonary premalignant lesions in both the KrasG12D-driven and nicotine-derived nitrosamine ketone (NNK)-induced mouse models of lung cancer, as well as in KrasG12D-driven and NNK-induced malignant transformed human bronchial epithelial cells (BEAS-2B and 16HBE). This suggests a potential correlation between the NQO1 expression and lung carcinogenesis. Based on this finding, we utilized β-Lapachone (β-Lap), an NQO1 bioactivatable drug, to suppress lung tumorigenesis. In this study, the efficacy and safety of low-dose β-Lap were demonstrated in preventing lung tumorigenesis in vivo. In conclusion, our study suggests that long-term consumption of low-dose β-Lap could potentially be an effective therapeutic strategy for the prevention of lung premalignant lesions. However, further studies and clinical trials are necessary to validate our findings, determine the safety of long-term β-Lap usage in humans, and promote the use of β-Lap in high-risk populations.

The Biological Role of Macrophage in Lung and Its Implications in Lung Cancer Immunotherapy

The lungs are the largest surface of the body and the most important organ in the respiratory system, which are constantly exposed to the external environment. Tissue Resident Macrophages in lung constitutes the important defense against external pathogens. Macrophages connects the innate and adaptive immune system, and also plays important roles in carcinogenesis and cancer immunotherapy. Lung cancer is the leading cause of cancer-related death worldwide, with an overall five-year survival rate of only 21%. Macrophages that infiltrate or aggregate in lung tumor microenvironment are defined as tumor-associated macrophages (TAMs). TAMs are the main components of immune cells in the lung tumor microenvironment. The differentiation and maturation process of TAMs can be roughly divided into two different types: classical activation pathway produces M1 tumor-associated macrophages, and bypass activation pathway produces M2 tumor-associated macrophages. Studies have found that TAMs are related to tumor invasion, metastasis, and treatment resistance, and show potential as a new target for tumor immunotherapy. Therefore, the biological function of macrophages in lung and the role of TAMs in the occurrence, development, and treatment of lung cancer are discussed in this paper.

Effects of senescence on the tumour microenvironment and response to therapy

Cellular senescence is a state of durable cell arrest that has been identified both in vitro and in vivo. It is associated with profound changes in gene expression and a specific secretory profile that includes pro-inflammatory cytokines, growth factors and matrix-remodelling enzymes, referred to as the senescence-associated secretory phenotype (SASP). In cancer, senescence can have anti- or pro-tumour effects. On one hand, it can inhibit tumour progression in a cell autonomous manner. On the other hand, senescence can also promote tumour initiation, progression, metastatic dissemination and resistance to therapy in a paracrine manner. Therefore, despite efforts to target senescence as a potential strategy to inhibit tumour growth, senescent cancer and microenvironmental cells can eventually lead to uncontrolled proliferation and aggressive tumour phenotypes. This can happen either through overcoming senescence growth arrest or through SASP-mediated effects in adjacent tumour cells. This review will discuss how senescence affects the tumour microenvironment, including extracellular matrix remodelling, the immune system and the vascular compartment, to promote tumourigenesis, metastasis and resistance to DNA-damaging therapies. It will also discuss current approaches used in the field to target senescence: senolytics, improving the immune clearance of senescent cells and targeting the SASP.

Macrophages and tumor-associated macrophages in the senescent microenvironment: From immunosuppressive TME to targeted tumor therapy

In-depth studies of the tumor microenvironment (TME) have helped to elucidate its cancer-promoting mechanisms and inherent characteristics. Cellular senescence, which acts as a response to injury and can the release of senescence-associated secretory phenotypes (SASPs). These SASPs release various cytokines, chemokines, and growth factors, remodeling the TME. This continual development of a senescent environment could be associated with chronic inflammation and immunosuppressive TME. Additionally, SASPs could influence the phenotype and function of macrophages, leading to the recruitment of tumor-associated macrophages (TAMs). This contributes to tumor proliferation and metastasis in the senescent microenvironment, working in tandem with immune regulation, angiogenesis, and therapeutic resistance. This comprehensive review covers the evolving nature of the senescent microenvironment, macrophages, and TAMs in tumor development. We also explored the links between chronic inflammation, immunosuppressive TME, cellular senescence, and macrophages. Moreover, we compiled various tumor-specific treatment strategies centered on cellular senescence and the current challenges in cellular senescence research. This study aimed to clarify the mechanism of macrophages and the senescent microenvironment in tumor progression and advance the development of targeted tumor therapies.

Royal Jelly: Biological Action and Health Benefits

Royal jelly (RJ) is a highly nutritious natural product with great potential for use in medicine, cosmetics, and as a health-promoting food. This bee product is a mixture of important compounds, such as proteins, vitamins, lipids, minerals, hormones, neurotransmitters, flavonoids, and polyphenols, that underlie the remarkable biological and therapeutic activities of RJ. Various bioactive molecules like 10-hydroxy-2-decenoic acid (10-HDA), antibacterial protein, apisin, the major royal jelly proteins, and specific peptides such as apisimin, royalisin, royalactin, apidaecin, defensin-1, and jelleins are characteristic ingredients of RJ. RJ shows numerous physiological and pharmacological properties, including vasodilatory, hypotensive, antihypercholesterolaemic, antidiabetic, immunomodulatory, anti-inflammatory, antioxidant, anti-aging, neuroprotective, antimicrobial, estrogenic, anti-allergic, anti-osteoporotic, and anti-tumor effects. Moreover, RJ may reduce menopause symptoms and improve the health of the reproductive system, liver, and kidneys, and promote wound healing. This article provides an overview of the molecular mechanisms underlying the beneficial effects of RJ in various diseases, aging, and aging-related complications, with special emphasis on the bioactive components of RJ and their health-promoting properties. The data presented should be an incentive for future clinical studies that hopefully will advance our knowledge about the therapeutic potential of RJ and facilitate the development of novel RJ-based therapeutic opportunities for improving human health and well-being.

Aging and cancer

Aging and cancer exhibit apparent links that we will examine in this review. The null hypothesis that aging and cancer coincide because both are driven by time, irrespective of the precise causes, can be confronted with the idea that aging and cancer share common mechanistic grounds that are referred to as 'hallmarks'. Indeed, several hallmarks of aging also contribute to carcinogenesis and tumor progression, but some of the molecular and cellular characteristics of aging may also reduce the probability of developing lethal cancer, perhaps explaining why very old age (> 90 years) is accompanied by a reduced incidence of neoplastic diseases. We will also discuss the possibility that the aging process itself causes cancer, meaning that the time-dependent degradation of cellular and supracellular functions that accompanies aging produces cancer as a byproduct or 'age-associated disease'. Conversely, cancer and its treatment may erode health and drive the aging process, as this has dramatically been documented for cancer survivors diagnosed during childhood, adolescence, and young adulthood. We conclude that aging and cancer are connected by common superior causes including endogenous and lifestyle factors, as well as by a bidirectional crosstalk, that together render old age not only a risk factor of cancer but also an important parameter that must be considered for therapeutic decisions.

Senescent Macrophages Release Inflammatory Cytokines and RNA-Loaded Extracellular Vesicles to Circumvent Fibroblast Senescence

Senescent cells, which accumulate with age, exhibit a pro-inflammatory senescence-associated secretory phenotype (SASP) that includes the secretion of cytokines, lipids, and extracellular vesicles (EVs). Here, we established an in vitro model of senescence induced by Raf-1 oncogene in RAW 264.7 murine macrophages (MΦ) and compared them to senescent MΦ found in mouse lung tumors or primary macrophages treated with hydrogen peroxide. The transcriptomic analysis of senescent MΦ revealed an important inflammatory signature regulated by NFkB. We observed an increased secretion of EVs in senescent MΦ, and these EVs presented an enrichment for ribosomal proteins, major vault protein, pro-inflammatory miRNAs, including miR-21a, miR-155, and miR-132, and several mRNAs. The secretion of senescent MΦ allowed senescent murine embryonic fibroblasts to restart cell proliferation. This antisenescence function of the macrophage secretome may explain their pro-tumorigenic activity and suggest that senolytic treatment to eliminate senescent MΦ could potentially prevent these deleterious effects.

Single-sEV profiling identifies the TACSTD2 + sEV subpopulation as a factor of tumor susceptibility in the elderly

BACKGROUND

Aging is a very complex physiological phenomenon, and sEVs are involved in the regulation of this mechanism. Serum samples from healthy individuals under 30 and over 60 years of age were collected to analyze differences in sEVs proteomics.

RESULTS

Based on PBA analysis, we found that sEVs from the serum of elderly individuals highly express TACSTD2 and identified a subpopulation marked by TACSTD2. Using ELISA, we verified the upregulation of TACSTD2 in serum from elderly human and aged mouse. In addition, we discovered that TACSTD2 was significantly increased in samples from tumor patients and had better diagnostic value than CEA. Specifically, 9 of the 13 tumor groups exhibited elevated TACSTD2, particularly for cervical cancer, colon cancer, esophageal carcinoma, liver cancer and thyroid carcinoma. Moreover, we found that serum sEVs from the elderly (especially those with high TACSTD2 levels) promoted tumor cell (SW480, HuCCT1 and HeLa) proliferation and migration.

CONCLUSION

TACSTD2 was upregulated in the serum of elderly individuals and patients with tumors, and could serve as a dual biomarker for aging and tumors.

Tumor-Associated Senescent Macrophages, Their Markers, and Their Role in Tumor Microenvironment

Tumor-associated macrophages (TAMs) are an important component of the tumor microenvironment (TME) and the most abundant population of immune cells infiltrating a tumor. TAMs can largely determine direction of anti-tumor immune response by promoting it or, conversely, contribute to formation of an immunosuppressive TME that allows tumors to evade immune control. Through interactions with tumor cells or other cells in the microenvironment and, as a result of action of anti-cancer therapy, macrophages can enter senescence. In this review, we have attempted to summarize information available in the literature on the role of senescent macrophages in tumors. With the recent development of senolytic therapeutic strategies aimed at removing senescent cells from an organism, it seems important to discuss functions of the senescent macrophages and potential role of the senolytic drugs in reprogramming TAMs to enhance anti-tumor immune response and improve efficacy of cancer treatment.

Cellular senescence is a double-edged sword in regulating aged immune responses to influenza

Clearance of senescent cells has demonstrated therapeutic potential in the context of chronic age-related diseases. Little is known, however, how clearing senescent cells affects the ability to respond to an acute infection and form quality immunological memory. We aimed to probe the effects of clearing senescent cells in aged mice on the immune response to influenza (flu) infection. We utilized a p16 trimodality reporter mouse model (p16-3MR) to allow for identification and selective clearance of p16-expressing cells upon administration of ganciclovir (GCV). While p16-expressing cells may exacerbate dysfunctional responses to a primary infection, our data suggest they may play a role in fostering memory cell generation. We demonstrate that although clearance of p16-expressing cells enhanced viral clearance, this also severely limited antibody production in the lungs of flu-infected aged mice. 30 days later, there were fewer flu-specific CD8 memory T cells and lower levels of flu-specific antibodies in the lungs of GCV-treated mice. Furthermore, GCV-treated mice were unable to mount an optimal memory response and demonstrated increased viral load following heterosubtypic challenge. These results suggest that targeting senescent cells may potentiate primary responses while limiting the ability to form durable and protective immune memory with age.

Prognostic significance of a signature based on senescence-related genes in colorectal cancer

Colorectal cancer, recognized as a quintessential age-related disease, underscores the intricate interplay between aging mechanisms and disease pathogenesis. Cellular senescence, a DNA damage-induced cellular stress response, is characterized by cell cycle arrest, the expression of an inflammatory senescence-associated secretory phenotype, and alterations in extracellular matrix metabolism. It is widely recognized as a fundamental and evolutionarily conserved mechanism of aging. Guided by geroscience principles, which assert that the pathogenesis of age-related diseases involves cellular mechanisms of aging, this study delves into the role of senescence-related genes in colon cancer progression. Leveraging a gene set reflective of senescence-associated pathways, we employed uni- and multivariate Cox proportional hazards survival analysis combined with the determination of the false discovery rate to analyze correlations between gene expression and survival. The integrated database of 1130 colon cancer specimens with available relapse-free survival time and relapse event data from ten independent cohorts provided a robust platform for survival analyses. We identified senescence-related genes associated with differential expression levels linked to shorter survival. Our findings unveil a prognostic signature utilizing cellular senescence-related genes (hazard ratio: 2.73, 95% CI 2.12-3.52, p = 6.4E - 16), offering valuable insights into survival prediction in colon cancer. Multivariate analysis underscored the independence of the senescence-related signature from available epidemiological and pathological variables. This study highlights the potential of senescence-related genes as prognostic biomarkers. Overall, our results underscore the pivotal role of cellular senescence, a fundamental mechanism of aging, in colon cancer progression.

Senescent-like macrophages mediate angiogenesis for endplate sclerosis via IL-10 secretion in male mice

Endplate sclerosis is a notable aspect of spine degeneration or aging, but the mechanisms remain unclear. Here, we report that senescent macrophages accumulate in the sclerotic endplates of lumbar spine instability (LSI) or aging male mouse model. Specifically, knockout of cdkn2a (p16) in macrophages abrogates LSI or aging-induced angiogenesis and sclerosis in the endplates. Furthermore, both in vivo and in vitro studies indicate that IL-10 is the primary elevated cytokine of senescence-related secretory phenotype (SASP). Mechanistically, IL-10 increases pSTAT3 in endothelial cells, leading to pSTAT3 directly binding to the promoters of Vegfa, Mmp2, and Pdgfb to encourage their production, resulting in angiogenesis. This study provides information on understanding the link between immune senescence and endplate sclerosis, which might be useful for therapeutic approaches.

Protein lipidation in cancer: mechanisms, dysregulation and emerging drug targets

Protein lipidation describes a diverse class of post-translational modifications (PTMs) that is regulated by over 40 enzymes, targeting more than 1,000 substrates at over 3,000 sites. Lipidated proteins include more than 150 oncoproteins, including mediators of cancer initiation, progression and immunity, receptor kinases, transcription factors, G protein-coupled receptors and extracellular signalling proteins. Lipidation regulates the physical interactions of its protein substrates with cell membranes, regulating protein signalling and trafficking, and has a key role in metabolism and immunity. Targeting protein lipidation, therefore, offers a unique approach to modulate otherwise undruggable oncoproteins; however, the full spectrum of opportunities to target the dysregulation of these PTMs in cancer remains to be explored. This is attributable in part to the technological challenges of identifying the targets and the roles of protein lipidation. The early stage of drug discovery for many enzymes in the pathway contrasts with efforts for drugging similarly common PTMs such as phosphorylation and acetylation, which are routinely studied and targeted in relevant cancer contexts. Here, we review recent advances in identifying targetable protein lipidation pathways in cancer, the current state-of-the-art in drug discovery, and the status of ongoing clinical trials, which have the potential to deliver novel oncology therapeutics targeting protein lipidation.

Air Pollution Drives Macrophage Senescence through a Phagolysosome-15-Lipoxygenase Pathway

Urban particulate matter (PM; uPM) poses significant health risks, particularly to the respiratory system. Fine particles, such as PM2.5, can penetrate deep into the lungs and exacerbate a range of health problems, including emphysema, asthma, and lung cancer. PM exposure is also linked to extrapulmonary disorders such as heart and neurodegenerative diseases. Moreover, prolonged exposure to elevated PM levels can reduce overall life expectancy. Senescence is a dysfunctional cell state typically associated with age but can also be precipitated by environmental stressors. This study aimed to determine whether uPM could drive senescence in macrophages, an essential cell type involved in particulate phagocytosis-mediated clearance. Although it is known that uPM exposure impairs immune function, this deficit is multifaceted and incompletely understood, partly because of the use of particulates such as diesel exhaust particles as a surrogate for true uPM. uPM was collected from several locations in the United States, including Baltimore, Houston, and Phoenix. Bone marrow-derived macrophages were stimulated with uPM or reference particulates (e.g., diesel exhaust particles) to assess senescence-related parameters. We report that uPM-exposed bone marrow-derived macrophages adopt a senescent phenotype characterized by increased IL-1α secretion, senescence-associated β-galactosidase activity, and diminished proliferation. Exposure to allergens failed to elicit such a response, supporting a distinction between different types of environmental exposure. uPM-induced senescence was independent of key macrophage activation pathways, specifically inflammasome and scavenger receptors. However, inhibition of the phagolysosome pathway abrogated senescence markers, supporting this phenotype's attribution to uPM phagocytosis. These data suggest that uPM exposure leads to macrophage senescence, which may contribute to immunopathology.

Macrophage senescence in health and diseases

Macrophage senescence, manifested by the special form of durable cell cycle arrest and chronic low-grade inflammation like senescence-associated secretory phenotype, has long been considered harmful. Persistent senescence of macrophages may lead to maladaptation, immune dysfunction, and finally the development of age-related diseases, infections, autoimmune diseases, and malignancies. However, it is a ubiquitous, multi-factorial, and dynamic complex phenomenon that also plays roles in remodeled processes, including wound repair and embryogenesis. In this review, we summarize some general molecular changes and several specific biomarkers during macrophage senescence, which may bring new sight to recognize senescent macrophages in different conditions. Also, we take an in-depth look at the functional changes in senescent macrophages, including metabolism, autophagy, polarization, phagocytosis, antigen presentation, and infiltration or recruitment. Furthermore, some degenerations and diseases associated with senescent macrophages as well as the mechanisms or relevant genetic regulations of senescent macrophages are integrated, not only emphasizing the possibility of regulating macrophage senescence to benefit age-associated diseases but also has an implication on the finding of potential targets or drugs clinically.

Type 2 cytokine signaling in macrophages protects from cellular senescence and organismal aging

Accumulation of senescent cells in organs and tissues is a hallmark of aging and known to contribute to age-related diseases. Although aging-associated immune dysfunction, or immunosenescence, is known to contribute to this process, the underlying mechanism remains elusive. Here, we report that type 2 cytokine signaling deficiency accelerated aging and, conversely, that the interleukin-4 (IL-4)-STAT6 pathway protected macrophages from senescence. Mechanistically, activated STAT6 promoted the expression of genes involved in DNA repair both via homologous recombination and Fanconi anemia pathways. Conversely, STAT6 deficiency induced release of nuclear DNA into the cytoplasm to promote tissue inflammation and organismal aging. Importantly, we demonstrate that IL-4 treatment prevented macrophage senescence and improved the health span of aged mice to an extent comparable to senolytic treatment, with further additive effects when combined. Together, our findings support that type 2 cytokine signaling protects macrophages from immunosenescence and thus hold therapeutic potential for improving healthy aging.

Prophylactic and long-lasting efficacy of senolytic CAR T cells against age-related metabolic dysfunction

Senescent cells, which accumulate in organisms over time, contribute to age-related tissue decline. Genetic ablation of senescent cells can ameliorate various age-related pathologies, including metabolic dysfunction and decreased physical fitness. While small-molecule drugs that eliminate senescent cells ('senolytics') partially replicate these phenotypes, they require continuous administration. We have developed a senolytic therapy based on chimeric antigen receptor (CAR) T cells targeting the senescence-associated protein urokinase plasminogen activator receptor (uPAR), and we previously showed these can safely eliminate senescent cells in young animals. We now show that uPAR-positive senescent cells accumulate during aging and that they can be safely targeted with senolytic CAR T cells. Treatment with anti-uPAR CAR T cells improves exercise capacity in physiological aging, and it ameliorates metabolic dysfunction (for example, improving glucose tolerance) in aged mice and in mice on a high-fat diet. Importantly, a single administration of these senolytic CAR T cells is sufficient to achieve long-term therapeutic and preventive effects.

Therapy-induced senescence is finally escapable, what is next?

Several breakthrough articles have recently confirmed the ability of tumor cells to escape the stable cell cycle arrest imposed by Therapy-Induced Senescence (TIS). Subsequently, accepting the hypothesis that TIS is escapable should encourage serious reassessments of the fundamental roles of senescence in cancer treatment. The potential for escape from TIS undermines the well-established tumor suppressor function of senescence, proposes it as a mechanism of tumor dormancy leading to disease recurrence and invites for further investigation of its unfavorable contribution to cancer therapy outcomes. Moreover, escaping TIS strongly indicates that the elimination of senescent tumor cells, primarily through pharmacological means, is a suitable approach for increasing the efficacy of cancer treatment, one that still requires further exploration. This commentary provides an overview of the recent evidence that unequivocally demonstrated the ability of therapy-induced senescent tumor cells in overcoming the terminal growth arrest fate and provides future perspectives on the roles of TIS in tumor biology.

The integration of multi-omics analysis and machine learning for the identification of prognostic assessment and immunotherapy efficacy through aging-associated genes in lung cancer

BACKGROUND

Recent years revealed key molecules in lung cancer research, yet their exact roles in disease onset and progression remain uncertain. Lung cancer's heterogeneity complicates prognosis prediction. This study integrates pivotal molecules to evaluate patient prognosis and immunotherapy efficacy.

METHODS

The WGCNA algorithm identified module genes linked to immunity. The Lasso-Cox method built a prognostic model for outcome prediction. GO and KEGG analyses explored gene pathways. ssGSEA quantified immune cell types and functions. The riskScore predicts the effectiveness of immunotherapy based on its correlation with DNA repair and immune checkpoint genes. Single-cell sequencing examined key gene expression across cell types.

RESULTS

Using WGCNA, we identified the MEbrown module related to immunity. Lasso-Cox selected "BLK," "ITGB4," "PRKCH," and "SNAI1" for the prognostic model. MF analysis revealed enriched functions including antigen binding, GTPase regulator activity. In terms of BP, processes like immune signaling and mitotic division were enriched. CC enrichment included immunoglobulin complexes and chromosomal regions. Enriched pathways encompassed Cell cycle, Focal adhesion, Cellular senescence, and p53 signaling. ssGSEA evaluated immune cell abundance. RiskScore correlated with CTLA4 and PD1 through MMR and immune checkpoint analysis. Single-cell analysis indicated gene expression across cell types for BLK, ITGB4, PRKCH, and SNAI1.

CONCLUSION

In summary, our developed prognostic model utilizing age-related genes effectively predicts lung cancer prognosis and the efficacy of immune therapy.

Air pollution drives macrophage senescence through a phagolysosome-15-lipoxygenase pathway

Urban particulate matter (uPM) poses significant health risks, particularly to the respiratory system. Fine particles, such as PM2.5, can penetrate deep into the lungs and exacerbate a range of health problems, including emphysema, asthma, and lung cancer. PM exposure is also linked to extra-pulmonary disorders like heart and neurodegenerative diseases. Moreover, prolonged exposure to elevated PM levels can reduce overall life expectancy. Senescence is a dysfunctional cell state typically associated with age but can also be precipitated by environmental stressors. This study aimed to determine whether uPM could drive senescence in macrophages, an essential cell type involved in particulate phagocytosis-mediated clearance. While it is known that uPM exposure impairs immune function, this deficit is multi-faceted and incompletely understood, partly due to the use of particulates such as diesel exhaust particle (DEP) as a surrogate for true uPM. uPM was collected from several locations in the USA, including Baltimore, Houston, and Phoenix. Bone marrow-derived macrophages (BMDMs) were stimulated with uPM or reference particulates (e.g., DEP) to assess senescence-related parameters. We report that uPM-exposed BMDMs adopt a senescent phenotype characterized by increased IL-1α secretion, senescence-associated β-galactosidase activity, and diminished proliferation. Exposure to allergens failed to elicit such a response, supporting a distinction between different types of environmental exposures. uPM-induced senescence was independent of key macrophage activation pathways, specifically inflammasome and scavenger receptor. However, inhibition of the phagolysosome pathway abrogated senescence markers, supporting this phenotype's attribution to uPM phagocytosis. These data suggest uPM exposure leads to macrophage senescence, which may contribute to immunopathology.

Implications of cellular senescence in paediatric pituitary tumours

The long-standing view of senescent cells as passive and dysfunctional biological remnants has recently shifted into a new paradigm where they are main players in the development of many diseases, including cancer. The senescence programme represents a first line of defence that prevents tumour cell growth but also leads to the secretion of multiple pro-inflammatory and pro-tumourigenic factors that fuel tumour initiation, growth, and progression. Here, we review the main molecular features and biological functions of senescent cells in cancer, including the outcomes of inducing or targeting senescence. We discuss evidence on the role of cellular senescence in pituitary tumours, with an emphasis on adamantinomatous craniopharyngioma (ACP) and pituitary adenomas. Although senescence has been proposed to be a tumour-preventing mechanism in pituitary adenomas, research in ACP has shown that senescent cells are tumour-promoting in both murine models and human tumours. Future studies characterizing the impact of targeting senescent cells may result in novel therapies against pituitary tumours.

Targeted single-cell RNA sequencing analysis reveals metabolic reprogramming and the ferroptosis-resistant state in hematologic malignancies

Hematologic malignancies are the most common hematopoietic diseases and a major public health concern. However, the mechanisms underlying myeloid tumors remain unknown owing to the intricate interplay between mutations and diverse clonal evolution patterns, as evidenced by the analysis of bulk cell-derived omics data. Several single-cell omics techniques have been used to characterize the hierarchies and altered immune microenvironments of hematologic malignancies. The comprehensive single-cell atlas of hematologic malignancies provides novel opportunities for personalized combinatorial targeted treatments, avoiding unwanted chemo-toxicity. In the present study, we performed transcriptome sequencing by combining single-cell RNA sequencing (scRNA-seq) with a targeted oncogenic gene panel for acute myeloid leukemia, overcoming the limitations of scRNA-seq in detecting oncogenic mutations. The distribution of oncogenic IDH1, IDH2, and KRAS mutations in each cell type was identified in the bone marrow (BM) samples of each patient. Our findings suggest that ferroptosis and metabolic reprogramming are involved in the tumorigenesis and chemotherapy resistance of oncogenic mutation-carrying cells. Biological progression via IDH1, IDH2, and KRAS mutations arrests hematopoietic maturation. Our study findings provide a rationale for using primary BM cells for personalized treatment in clinical settings.

Influences of Aged Bone Marrow Macrophages on Skeletal Health and Senescence

PURPOSE OF REVIEW

The purpose of this review is to discuss the role of macrophages in the regulation of skeletal health with age, particularly in regard to both established and unexplored mechanisms in driving inflammation and senescence.

RECENT FINDINGS

A multitude of research has uncovered mechanisms of intrinsic aging in macrophages, detrimental factors released by these immune cells, and crosstalk from senescent mesenchymal cell types, which altogether drive age-related bone loss. Furthermore, bone marrow macrophages were recently proposed to be responsible for the megakaryocytic shift during aging and overall maintenance of the hematopoietic niche. Studies on extra-skeletal macrophages have shed light on possible conserved mechanisms within bone and highlight the importance of these cells in systemic aging. Macrophages are a critically important cell type in maintaining skeletal homeostasis with age. New discoveries in this area are of utmost importance in fully understanding the pathogenesis of osteoporosis in aged individuals.

Targeting tumor-associated macrophage: an adjuvant strategy for lung cancer therapy

The emergence of immunotherapy has revolutionized the treatment landscape for various types of cancer. Nevertheless, lung cancer remains one of the leading causes of cancer-related mortality worldwide due to the development of resistance in most patients. As one of the most abundant groups of immune cells in the tumor microenvironment (TME), tumor-associated macrophages (TAMs) play crucial and complex roles in the development of lung cancer, including the regulation of immunosuppressive TME remodeling, metabolic reprogramming, neoangiogenesis, metastasis, and promotion of tumoral neurogenesis. Hence, relevant strategies for lung cancer therapy, such as inhibition of macrophage recruitment, TAM reprograming, depletion of TAMs, and engineering of TAMs for drug delivery, have been developed. Based on the satisfactory treatment effect of TAM-targeted therapy, recent studies also investigated its synergistic effect with current therapies for lung cancer, including immunotherapy, radiotherapy, chemotherapy, anti-epidermal growth factor receptor (anti-EGFR) treatment, or photodynamic therapy. Thus, in this article, we summarized the key mechanisms of TAMs contributing to lung cancer progression and elaborated on the novel therapeutic strategies against TAMs. We also discussed the therapeutic potential of TAM targeting as adjuvant therapy in the current treatment of lung cancer, particularly highlighting the TAM-centered strategies for improving the efficacy of anti-programmed cell death-1/programmed cell death-ligand 1 (anti-PD-1/PD-L1) treatment.

Tumor cell-induced macrophage senescence plays a pivotal role in tumor initiation followed by stable growth in immunocompetent condition

BACKGROUND

The cancer stem cell theory proposes that tumor formation in vivo is driven only by specific tumor-initiating cells having stemness; however, clinical trials conducted to test drugs that target the tumor stemness provided unsatisfactory results thus far. Recent studies showed clear involvement of immunity in tumors; however, the requirements of tumor-initiation followed by stable growth in immunocompetent individuals remain largely unknown.

METHODS

To clarify this, we used two similarly induced glioblastoma lines, 8B and 9G. They were both established by overexpression of an oncogenic H-RasL61 in p53-deficient neural stem cells. In immunocompromised animals in an orthotopic transplantation model using 1000 cells, both show tumor-forming potential. On the other hand, although in immunocompetent animals, 8B shows similar tumor-forming potential but that of 9G's are very poor. This suggests that 8B cells are tumor-initiating cells in immunocompetent animals. Therefore, we hypothesized that the differences in the interaction properties of 8B and 9G with immune cells could be used to identify the factors responsible for its tumor forming potential in immunocompetent animals and performed analysis.

RESULTS

Different from 9G, 8B cells induced senescence-like state of macrophages around tumors. We investigated the senescence-inducing factor of macrophages by 8B cells and found that it was interleukin 6. Such senescence-like macrophages produced Arginase-1, an immunosuppressive molecule known to contribute to T-cell hyporesponsiveness. The senescence-like macrophages highly expressed CD38, a nicotinamide adenine dinucleotide (NAD) glycohydrolase associated with NAD shortage in senescent cells. The addition of nicotinamide mononucleotide (NMN), an NAD precursor, in vitro inhibited to the induction of macrophage senescence-like phenotype and inhibited Arginase-1 expression resulting in retaining T-cell function. Moreover, exogenous in vivo administration of NMN after tumor inoculation inhibited tumor-initiation followed by stable growth in the immunocompetent mouse tumor model.

CONCLUSIONS

We identified one of the requirements for tumor-initiating cells in immunocompetent animals. In addition, we have shown that tumor growth can be inhibited by externally administered NMN against macrophage senescence-like state that occurs in the very early stages of tumor-initiating cell development. This therapy targeting the immunosuppressive environment formed by macrophage senescence-like state is expected to be a novel promising cancer therapeutic strategy.

Nuclear envelope disruption triggers hallmarks of aging in lung alveolar macrophages

Aging is characterized by gradual immune dysfunction and increased disease risk. Genomic instability is considered central to the aging process, but the underlying mechanisms of DNA damage are insufficiently defined. Cells in confined environments experience forces applied to their nucleus, leading to transient nuclear envelope rupture (NER) and DNA damage. Here, we show that Lamin A/C protects lung alveolar macrophages (AMs) from NER and hallmarks of aging. AMs move within constricted spaces in the lung. Immune-specific ablation of lamin A/C results in selective depletion of AMs and heightened susceptibility to influenza virus-induced pathogenesis and lung cancer growth. Lamin A/C-deficient AMs that persist display constitutive NER marks, DNA damage and p53-dependent senescence. AMs from aged wild-type and from lamin A/C-deficient mice share a lysosomal signature comprising CD63. CD63 is required to limit damaged DNA in macrophages. We propose that NER-induced genomic instability represents a mechanism of aging in AMs.

Quantitative biochemical phenotypic heterogeneity of senescent macrophage at a single cell level by Synchrotron Radiation Fourier Transform Infrared Microspectroscopy

Macrophage senescence plays an important role in pathophysiological process of age-related diseases such as atherosclerosis, chronic obstructive pulmonary disease (COPD), pulmonary fibrosis, and lung cancer. After macrophage senescence, the biochemical phenotypes related to biological functions showed great heterogeneity. However, the biochemical phenotype and phenotypic heterogeneity of senescent macrophage has not been fully understood. Exploring the phenotype of biochemical substances in senescent macrophage will be helpful for understanding the function of senescent macrophage and finding out the potential mechanism between immune macrophage senescence and age-related diseases. In this study, we employed SR-FTIR microspectroscopy to detect the biochemical phenotype and phenotypic heterogeneity of single macrophage. The whole infrared spectra of senescent macrophages shifted, indicating biochemical substance changes within senescent macrophages. PCA and intercellular Euclidean distance statistical analysis based on specific spectra regions revealed dynamic changes of lipids and proteins during macrophage senescence. This proved that SR-FTIR microspectroscopy is an effective tool to detect the single cell biochemical phenotype transformation and phenotypic heterogeneity during macrophage senescence. It is of great significance to provide an evaluation method or clue for the study of cellular functions related to intracellular biochemical substances.