Senescence and the tumor-immune landscape: Implications for cancer immunotherapy

Targeting DUSP3 promotes cell senescence by activating the notch1 pathway to treat hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a malignant tumor of the digestive system, influenced by various factors. Due to its subtle clinical symptoms, it delayed results in poor prognosis and limited treatment options. Cellular senescence, characterized by stable growth arrest, is closely linked to tumor proliferation inhibition, making it a promising therapeutic strategy for HCC. However, the role of Dual Specificity Phosphatase 3 (DUSP3) in HCC-induced senescence and its underlying mechanisms remain poorly understood. Our preliminary data show a marked upregulation of DUSP3 in HCC tissues compared to adjacent group. Additionally, DUSP3 knockdown induced senescence in HCC cells in vitro. Further investigation revealed that inhibiting Notch1 reversed the senescence induced by DUSP3 knockdown in these cells. Thus, targeting DUSP3 to activate the Notch1 pathway and induction of senescence as a promising anti-tumor strategy.

Exercise alleviates osteoporosis by regulating the secretion of the Senescent Associated Secretory Phenotype

As the elderly population grows, the number of patients with metabolic bone diseases such as osteoporosis has increased sharply, posing a significant threat to public health and social economics. Although pharmacological therapies for osteoporosis demonstrate therapeutic benefits, their prolonged use is associated with varying degrees of adverse effects. As a non-pharmacological intervention, exercise is widely recognized for its cost-effectiveness, safety, and lack of toxic side effects, making it a recommended treatment for osteoporosis prevention and management. Previous studies have demonstrated that exercise can improve metabolic bone diseases by modulating the Senescent Associated Secretory Phenotype (SASP). However, the mechanisms through which exercise influences SASP remain unclear. Therefore, this review aims to summarize the effects of exercise on SASP and elucidate the specific mechanisms by which exercise regulates SASP to alleviate osteoporosis, providing a theoretical basis for osteoporosis through exercise and developing targeted therapies.

Role of Senescence-Associated Biomarkers and Immune Dynamics in Predicting Response to Neoadjuvant Chemoradiotherapy in Rectal Cancer

Objective

Neoadjuvant chemoradiotherapy (nCRT) is one of the standard treatments for locally advanced rectal cancer (LARC). However, the therapeutic responses to this form of treatment greatly vary from one patient to another. In this work, we focused on changes of serum senescence-associated secretory phenotype (SASP) factors and immune cell infiltration post-nCRT in a search for possible predictors of response to nCRT.

Methods

Twenty rectal cancer patients treated with nCRT were included and underwent assessments before (pre-) and after (post-) the treatment. Inflammatory cytokines such as IL-1α, IL-6, and IL-8; chemokines such as CCL5, CXCL1, and CCL2 in serum; and immune cell infiltrations including CD8+, CD4+, and CD206+ macrophages were assessed by ELISA and IHC, respectively. Tumor regressions were evaluated by MSK three-tier TRG grading system.

Results

Significant post-nCRT upregulation of IL-6, IL-8, IL-1α, CRP, CCL5, and CXCL1 was found, together with increased CD8+ T cell infiltration in tumor regression responders. IL-1α and CCL2 pre-nCRT levels were promised as predictive biomarkers, given that higher pretreatment levels were associated with lower tumor regression. Increased CD8+ cytotoxic T cell infiltration improved treatment outcome, whereas the changes in CD4+ T cells and M2 macrophages did not reach statistical significance.

Conclusion

IL-1α, CCL2, and CD8+ T cells, were identified as candidate markers that might monitor nCRT effectiveness in rectal cancer patients. These findings reinforce insights into the tumor microenvironment modulated by SASP components and immune cells and imply the need for larger studies to validate such associations.

Cellular senescence offers distinct immunological vulnerabilities in cancer

Chronic damage following oncogene induction or cancer therapy can produce cellular senescence. Senescent cells not only exit the cell cycle but communicate damage signals to their environment that can trigger immune responses. Recent work has revealed that senescent tumor cells are highly immunogenic, leading to new ways to activate antitumor immunosurveillance and potentiate T cell-directed immunotherapies. However, other studies have determined that heterogeneous senescent stromal cell populations contribute to immunosuppression and tumor progression, sparking the development of senotherapeutics to target senescent cells that evade immune detection. We review current findings that provide deeper insights into the mechanisms contributing to the dichotomous role of senescence in immune modulation and how that can be leveraged for cancer immunotherapy.

Cellular senescence in tumor immune escape: Mechanisms, implications, and therapeutic potential

Cellular senescence, a hallmark of aging, has emerged as a captivating area of research in tumor immunology with profound implications for cancer prevention and treatment. In the tumor microenvironment, senescent cells exhibit a dual role, simultaneously hindering tumor development through collaboration with immune cells and evading immune cell attacks by upregulating immunoinhibitory proteins. However, the intricate immune escape mechanism of cellular senescence in the tumor microenvironment remains a subject of intense investigation. Chronic inflammation is exacerbated by cellular senescence through the upregulation of pro-inflammatory factors such as interleukin-1β, thereby augmenting the risk of tumorigenesis. Additionally, the interplay between autophagy and cellular senescence adds another layer of complexity. Autophagy, known to slow down the aging process by reducing p53/p21 levels, may be downregulated by cellular senescence. To harness the therapeutic potential of cellular senescence, targeting its immunological aspects has gained significant attention. Strategies such as immune checkpoint inhibitors and T-cell senescence inhibition are being explored in the context of cellular senescence immunotherapy. In this comprehensive review, we provide a compelling overview of the regulation of cellular senescence and delve into the influencing factors, including chronic inflammation, autophagy, and circadian rhythms, associated with senescence in the tumor microenvironment. We specifically focus on unraveling the enigmatic dual role of cellular senescence in tumor immune escape. By deciphering the intricate nature of cellular senescence in the tumor microenvironment, this review aims to advance our understanding and pave the way for leveraging senescence as a promising target for tumor immunotherapy applications.

ALDH1A3 Regulates Cellular Senescence and Senescence-Associated Secretome in Prostate Cancer

Background: Radiotherapy is a key treatment for cancer, effectively controlling local tumor growth through DNA damage that induces senescence or apoptosis in cancer cells. However, radiotherapy can trigger complex cellular reactions, such as cell senescence, which is characterized by irreversible cell cycle arrest and the secretion of pro-inflammatory factors known as the senescent-associated secretory phenotype (SASP). Methods: This study investigates the regulatory role of ALDH1A3, a key enzyme implicated in cancer cell metabolism and radiotherapy resistance, in the induction of senescence and SASP. Using in vitro models, we demonstrate that ALDH1A3 knockdown accelerates cellular senescent-like phenotype while regulating the SASP through the cGAS-STING immune response pathway. Results: Our results indicate that while ALDH1A3 knockdown promotes senescence, it reduces the secretion of pro-inflammatory factors via inhibition of the cGAS-STING pathway, potentially mitigating SASP-related tumor progression. Conclusions: These findings provide insights into the molecular mechanisms underlying prostate cancer cell senescence and suggest that ALDH1A3 could be a potential therapeutic target to enhance the efficacy of radiotherapy while controlling the adverse effects of SASP.

Senescent vascular endothelial cells promote oral squamous cell carcinoma progression through complement C3 activation

OBJECTIVE

The tumour microenvironment (TME) plays a critical role in therapeutic response and clinical outcomes in cancer. Senescent stromal cells have been shown to promote tumour progression; however, the role of senescent vascular endothelial cells (VECs) in oral squamous cell carcinoma (OSCC) remains largely unknown. In this study, we aimed to explore the effects and potential mechanisms of senescent VECs in OSCC progression.

DESIGN

Cisplatin was used to induce senescence in two endothelial cell lines. Senescence-associated β-galactosidase (SA-β-gal) staining, immunoblotting, cell cycle and proliferation assays, and migration and invasion assays were performed to access senescence development and biological behavior. Additionally, RNA sequencing analysis, multiplex immunohistochemical staining, immunoblotting, and xenograft mouse models were used to investigate the senescence-associated secretory phenotype of senescent VECs during OSCC progression and its potential molecular mechanisms.

RESULTS

Cisplatin-induced senescent VECs exhibited senescence-related changes, including positive SA-β-gal expression and upregulation of p16, p21, and p53, along with attenuated proliferation and migration. Notably, cisplatin-induced VEC senescence promoted OSCC cell proliferation, migration, and invasion by activating complement C3. Increased gene and protein levels of C3 were observed in cisplatin-treated senescent VECs. Inhibition of C3 in vitro and in vivo reduced OSCC cell proliferation and invasion.

CONCLUSION

Senescent VECs induced by cisplatin promote OSCC proliferation and invasion through complement C3 activation. Targeting complement C3 in senescent VECs may offer a novel therapeutic strategy for OSCC treatment.

Molecular signatures of cellular senescence in cancer: a critical review of prognostic implications and therapeutic opportunities

Cellular senescence is a state of permanent loss of proliferative capacity. Therefore, cells that reach a senescent state prevent tumor initiation, acting as an anti-tumor mechanism. However, despite not being proliferative, senescent cells have high secretory activity, constituting the Senescence-Associated Secretory Phenotype (SASP). SASP includes thousands of soluble molecules and extracellular vesicles, through which senescent cells can affect other cells and the extracellular matrix. In advanced tumors, the enrichment of senescent cells can have anti- or pro-tumor effects depending on features like SASP composition, tumor microenvironment (TME) composition, the anatomic site, histopathologic characteristics of malignancy, and tumor molecular background. We reviewed the studies assessing the impact of the senescence status, measured by mRNA or lncRNA molecular signatures, in the prognosis and other clinically relevant information in cancer, including anti-tumor immunity and response to therapy. We discussed the pros and cons of different strategies to define those molecular signatures and the main limitations of the studies. Finally, we also raised clinical challenges regarding the crossroad between cellular senescence and cancer prognosis, including some therapeutic opportunities in the field.

Circadian rhythm, hypoxia, and cellular senescence: From molecular mechanisms to targeted strategies

Cellular senescence precipitates a decline in physiological activities and metabolic functions, often accompanied by heightened inflammatory responses, diminished immune function, and impaired tissue and organ performance. Despite extensive research, the mechanisms underpinning cellular senescence remain incompletely elucidated. Emerging evidence implicates circadian rhythm and hypoxia as pivotal factors in cellular senescence. Circadian proteins are central to the molecular mechanism governing circadian rhythm, which regulates homeostasis throughout the body. These proteins mediate responses to hypoxic stress and influence the progression of cellular senescence, with protein Brain and muscle arnt-like 1 (BMAL1 or Arntl) playing a prominent role. Hypoxia-inducible factor-1α (HIF-1α), a key regulator of oxygen homeostasis within the cellular microenvironment, orchestrates the transcription of genes involved in various physiological processes. HIF-1α not only impacts normal circadian rhythm functions but also can induce or inhibit cellular senescence. Notably, HIF-1α may aberrantly interact with BMAL1, forming the HIF-1α-BMAL1 heterodimer, which can instigate multiple physiological dysfunctions. This heterodimer is hypothesized to modulate cellular senescence by affecting the molecular mechanism of circadian rhythm and hypoxia signaling pathways. In this review, we elucidate the intricate relationships among circadian rhythm, hypoxia, and cellular senescence. We synthesize diverse evidence to discuss their underlying mechanisms and identify novel therapeutic targets to address cellular senescence. Additionally, we discuss current challenges and suggest potential directions for future research. This work aims to deepen our understanding of the interplay between circadian rhythm, hypoxia, and cellular senescence, ultimately facilitating the development of therapeutic strategies for aging and related diseases.

The role of GATA4 in mesenchymal stem cell senescence: A new frontier in regenerative medicine

The Mesenchymal Stem Cell (MSC) is a multipotent progenitor cell with known differentiation potential towards various cell lineage, making it an appealing candidate for regenerative medicine. One major contributing factor to age-related MSC dysfunction is cellular senescence, which is the hallmark of relatively irreversible growth arrest and changes in functional properties. GATA4, a zinc-finger transcription factor, emerges as a critical regulator in MSC biology. Originally identified as a key regulator of heart development and specification, GATA4 has since been connected to several aspects of cellular processes, including stem cell proliferation and differentiation. Accumulating evidence suggests that the involvement of GATA4-nuclear signalizing in the process of MSC senescence-related traits may contribute to age-induced alterations in MSC behavior. GATA4 emerged as the central player in MSC senescence, interacting with several signaling pathways. Studies have shown that GATA4 expression is reduced with age in MSCs, which is associated with increased expression levels of senescence markers and impaired regenerative potential. At the mechanistic level, GATA4 regulates the expression of genes involved in cell cycle regulation, DNA repair, and oxidative stress response, thereby influencing the senescence phenotype in MSCs. The findings underscore the critical function of GATA4 in MSC homeostasis and suggest a promising new target to restore stem cell function during aging and disease. A better understanding of the molecular mechanisms that underlie GATA4 mediated modulation of MSC senescence would provide an opportunity to develop new therapies to revitalize old MSCs to increase their regenerative function for therapeutic purposes in regenerative medicine.

Recent Advances in Anti-Aging Therapeutic Strategies Targeting DNA Damage Response and Senescence-Associated Secretory Phenotype-Linked Signaling Cascade

Aging is considered the contributory accumulation of abruptions occurring through cell signaling cascades, which ultimately cause changes in physical functions, cell fate, and damage across all organ systems. DNA damage response (DDR) also occurs through telomere shortening, tumor formation, mitochondrial dysfunction, and so forth. Cellular aging occurs through cell cycle arrest, which is the result of extended DDR cascade signaling networks via MDC1, 53BP1, H2AX, ATM, ARF, P53, P13-Akt, BRAF, Sirtuins, NAD + , and so forth. These persistent cell cycle arrests initiated by DDR and other associated stress-induced signals promote a permanent state of cell cycle arrest called senescence-associated secretory phenotype (SASP). However, cellular aging gets accelerated with faulty DNA repair systems, and the produced senescent cells further generate various promoting contributors to age-related dysfunctional diseases including SASP. Any changes to these factors contribute to age-related disease development. Therefore, this review explores anti-aging factors targeting DDR and SASP regulation and their detailed signaling networks. In addition, it allows researchers to identify anti-aging targets and anti-aging therapeutic strategies based on identified and nonidentified targets.

Cellular senescence: from homeostasis to pathological implications and therapeutic strategies

Cellular aging is a multifactorial and intricately regulated physiological process with profound implications. The interaction between cellular senescence and cancer is complex and multifaceted, senescence can both promote and inhibit tumor progression through various mechanisms. M6A methylation modification regulates the aging process of cells and tissues by modulating senescence-related genes. In this review, we comprehensively discuss the characteristics of cellular senescence, the signaling pathways regulating senescence, the biomarkers of senescence, and the mechanisms of anti-senescence drugs. Notably, this review also delves into the complex interactions between senescence and cancer, emphasizing the dual role of the senescent microenvironment in tumor initiation, progression, and treatment. Finally, we thoroughly explore the function and mechanism of m6A methylation modification in cellular senescence, revealing its critical role in regulating gene expression and maintaining cellular homeostasis. In conclusion, this review provides a comprehensive perspective on the molecular mechanisms and biological significance of cellular senescence and offers new insights for the development of anti-senescence strategies.

DEAD-box RNA helicase DDX-23 mediates dietary restriction induced health span in Caenorhabditis elegans

Dietary restriction (DR) extends lifespan in diverse species, from yeast to mammals. However, its underlying mechanisms are not well understood. In this study, through using the tractable model Caenorhabditis elegans, we show a role for the DEAD-box RNA helicase, DDX-23 (homologous to mammal DDX23) as a regulator of healthspan in response to dietary restriction. Meanwhile, DDX-23 is also required for heat and oxidative stress response in C. elegans. Intriguingly, DDX-23 functions in the germline during adult to regulate dietary restriction-induced longevity. We then find that PHA-4/FOXA acts downstream of DDX-23 to mediate the transcriptional response of SOD-related genes and consequently the lifespan of the animals. Furthermore, we find that the DEAD-box RNA helicase, DDX-23 negatively regulates the healthy lifespan extension by up-regulating the expression of miR-231, and resulting in suppressing the activation of FOXO transcription factor DAF-16. Our work shows a newly discovered for DEAD-box RNA helicase DDX-23 in the regulation of dietary restriction-mediated longevity in C. elegans and reveals the downstream transcriptional regulation mechanisms.

RB functions as a key regulator of senescence and tumor suppression

The Retinoblastoma (RB) protein is crucial for regulating gene transcription and chromatin remodeling, impacting cell cycle progression, cellular senescence, and tumorigenesis. Cellular senescence, characterized by irreversible growth arrest and phenotypic alterations, serves as a vital barrier against tumor progression and age-related diseases. RB is crucial in mediating senescence and tumor suppression by modulating the RB-E2F pathway and cross talking with other key senescence effectors such as p53 and p16INK4a. The interplay between RB-mediated cell cycle arrest and cellular senescence offers critical insights into tumorigenesis and potential therapeutic strategies. Leveraging RB-mediated senescence presents promising opportunities for cancer therapy, including novel approaches in tumor immunotherapy designed to enhance treatment efficacy. This review highlights recent advancements in the RB signaling pathway, focusing on its roles in cellular senescence and tumor suppression, and discusses its potential to improve tumor management and clinical outcomes.

A stumbling block in pancreatic cancer treatment: drug resistance signaling networks

The primary node molecules in the cell signaling network in cancer tissues are maladjusted and mutated in comparison to normal tissues, which promotes the occurrence and progression of cancer. Pancreatic cancer (PC) is a highly fatal cancer with increasing incidence and low five-year survival rates. Currently, there are several therapies that target cell signaling networks in PC. However, PC is a "cold tumor" with a unique immunosuppressive tumor microenvironment (poor effector T cell infiltration, low antigen specificity), and targeting a single gene or pathway is basically ineffective in clinical practice. Targeted matrix therapy, targeted metabolic therapy, targeted mutant gene therapy, immunosuppressive therapy, cancer vaccines, and other emerging therapies have shown great therapeutic potential, but results have been disappointing. Therefore, we summarize the identified and potential drug-resistant cell signaling networks aimed at overcoming barriers to existing PC therapies.

Chemotherapy-induced cellular senescence promotes stemness of aggressive B-cell non-Hodgkin's lymphoma via CCR7/ARHGAP18/IKBα signaling activation

BACKGROUND

Resistance to existing therapies is a major cause of treatment failure in patients with refractory and relapsed B-cell non-Hodgkin's lymphoma (r/r B-NHL). Therapy-induced senescence (TIS) is one of the most important mechanisms of drug resistance.

METHODS

This study used single-cell RNA sequencing to analyze doxorubicin-induced senescent B-NHL cells. C-C chemokine receptor 7 (CCR7) expression in patients with aggressive B-NHL was assessed using immunohistochemistry and flow cytometry. Lentiviral transfection was used to target CCR7 expression in Raji and SU-DHL-2 cells. Protein localization was visualized through immunofluorescence, while western blotting and co-immunoprecipitation were used to analyze protein expression and interactions. Cell proliferation was measured with the Cell Counting Kit-8 assay, and senescent cells were detected using senescence-associated β-galactosidase staining. The stemness of cells was evaluated through colony and sphere formation assays. Transwell assays assessed cell migration and invasion. Finally, inhibitors GS143 and Y27632 were used to examine the effect of IKBα and ARHGAP/RhoA inhibition on B-NHL-TIS.

RESULTS

Here we identified a distinct group of TIS, composed of memory B-cell population characterized by strong positive expression of CCR7, which was significantly elevated in TIS population compared with normal proliferating and autonomously senescent lymphoma cell populations. Additionally, CCR7 expression was significantly upregulated in patients with r/r B-NHL, and was an independent prognostic factor in B-NHL, with high CCR7 expression being strongly associated with poor prognosis. In vitro results indicated that CCL21 induced migration and invasion of B-NHL cells via CCR7, while blocking CCR7 reduced doxorubicin-induced migration and invasion of these cells. Furthermore, B-NHL-TIS regulated by CCR7 and exhibited enhanced phenotypic and functional stemness features, including the upregulation of stemness markers, increased colony-forming, invasive and migratory capabilities. Mechanistically, blocking CCR7 reversed the stemness characteristics of senescent B-NHL cells by inhibiting the activation of ARHGAP18/IKBα signaling.

CONCLUSIONS

Together, TIS promotes the stemness of B-NHL cells via CCR7/ARHGAP18/IKBα signaling activation and targeting CCR7/ARHGAP18 might overcome the chemoresistance of senescent B-NHL cells by inhibiting stemness acquisition and maintenance.

Deciphering potential molecular mechanisms in clear cell renal cell carcinoma based on the ubiquitin-conjugating enzyme E2 related genes: Identifying UBE2C correlates to infiltration of regulatory T cells

Renal clear cell carcinoma (ccRCC) is a highly aggressive and common form of kidney cancer, with limited treatment options for advanced stages. Recent studies have highlighted the importance of the ubiquitin-proteasome system in tumor progression, particularly the role of ubiquitin-conjugating enzyme E2 (UBE2) family members. However, the prognostic significance of UBE2-related genes (UBE2RGs) in ccRCC remains unclear. In this study, bulk RNA-sequencing and single-cell RNA-sequencing data from ccRCC patients were retrieved from the Cancer Genome Atlas and Gene Expression Omnibus databases. Differential expression analysis was performed to identify UBE2RGs associated with ccRCC. A combination of 10 machine learning methods was applied to develop an optimal prognostic model, and its predictive performance was evaluated using area under the curve (AUC) values for 1-, 3-, and 5-year overall survival (OS) in both training and validation cohorts. Functional enrichment analyses of gene ontology and Kyoto Encyclopedia of Genes and Genomes were conducted to explore the biological pathways involved. Correlation analysis was conducted to investigate the association between the risk score and tumor mutational burden (TMB) and immune cell infiltration. Immunotherapy and chemotherapy sensitivity were assessed by immunophenoscore and tumor immune, dysfunction, and exclusion scores to identify potential predictive significance. In vitro, knockdown of the key gene UBE2C in 786-O cells by specific small interfering RNA to validate its impact on apoptosis, migration, cell cycle, migration, invasion of tumor cells, and induction of regulatory T cells (Tregs). Analysis of sc-RNA revealed that UBE2 activity was significantly upregulated in malignant cells, suggesting its role in tumor progression. A three-gene prognostic model comprising UBE2C, UBE2D3, and UBE2T was constructed by Lasoo Cox regression and demonstrated robust predictive accuracy, with AUC values of 0.745, 0.766, and 0.771 for 1-, 3-, and 5-year survival, respectively. The model was validated as an independent prognostic factor in ccRCC. Patients in the high-risk group had a worse prognosis, higher TMB scores, and low responsiveness to immunotherapy. Additionally, immune infiltration and chemotherapy sensitivity analyses revealed that UBE2RGs are associated with various immune cells and drugs, suggesting that UBE2RGs could be a potential therapeutic target for ccRCC. In vitro experiments confirmed that the reduction of UBE2C led to an increase in apoptosis rate, as well as a decrease in tumor cell invasion and metastasis abilities. Additionally, si-UBE2C cells reduced the release of the cytokine Transforming Growth Factor-beta 1 (TGF-β1), leading to a decreased ratio of Tregs in the co-culture system. This study presents a novel three-gene prognostic model based on UBE2RGs that demonstrates significant predictive value for OS, immunotherapy, and chemotherapy in ccRCC patients. The findings underscore the potential of UBE2 family members as biomarkers and therapeutic targets in ccRCC, warranting further investigation in prospective clinical trials.

GADD45β-MTK1 signaling axis mediates oncogenic stress-induced activation of the p38 and JNK pathways

The ERK pathway governs essential biological processes such as cell proliferation and survival, and its hyperactivation by various oncogenes ultimately drives carcinogenesis. However, normal mammalian cells typically recognize aberrant ERK signaling as oncogenic stress and respond by inducing cell cycle arrest or apoptosis through activation of the p38 and JNK pathways. Despite the critical role of this response in preventing carcinogenesis, the precise molecular mechanisms underlying oncogene-induced, ERK-dependent activation of p38/JNK and its tumor-suppressive effects remain unclear. Here, we demonstrate that MAP three kinase 1 (MTK1), a stress-responsive MAPKKK, serves as a key mediator of p38/JNK activation induced by oncogenic ERK signaling. Mechanistically, aberrant ERK signaling induces sustained expression of the transcription factor early growth response protein 1 (EGR1), which promotes the production of the MTK1 activator GADD45β, leading to persistent activation of MTK1-p38/JNK signaling. Gene knockout and transcriptome analyses revealed that this GADD45β/MTK1-mediated cross-talk between the ERK and p38/JNK pathways preferentially upregulates a specific set of genes involved in apoptosis and the immune response. Notably, the expression of EGR1, GADD45β, and MTK1 is frequently downregulated in many cancers with high ERK activity, resulting in the disruption of the tumor-suppressive ERK-p38/JNK cross-talk. Restoring GADD45β expression in cancer cells reactivates p38/JNK signaling and suppresses tumorigenesis. Our findings delineate a molecular mechanism by which normal cells sense and respond to oncogenic stress to prevent abnormal growth, and highlight the significance of its dysregulation in cancer.

Immune senescence: A key player in cancer biology

With the rapid development of immunological techniques in recent years, our understanding of immune senescence has gradually deepened, but the role of immune senescence in cancer biology remains incompletely elucidated. Understanding these mechanisms and interactions is crucial for the development of tumor biology. This review examines five key areas: the classification and main features of immune senescence, factors influencing immune cell senescence in cancer, the reciprocal causal cycle between immune senescence and malignancy, and the potential of immune senescence as a target for cancer immunotherapy.

Chronic kidney disease and aging: dissecting the p53/p21 pathway as a therapeutic target

Chronic kidney diseases (CKD) are a group of multi-factorial disorders that markedly impair kidney functions with progressive renal deterioration. Aging contributes to age-specific phenotypes in kidneys, which undergo several structural and functional alterations, such as a decline in regenerative capacity and increased fibrosis, inflammation, and tubular atrophy, all predisposing them to disease and increasing their susceptibility to injury while impeding their recovery. A central feature of these age-related processes is the activation of the p53/p21 pathway signaling. The pathway is a key player in cellular senescence, apoptosis, and cell cycle regulation, which are all key to maintaining the health of the kidney. P53 is a transcription factor and a tumor suppressor protein that responds to cell stress and damage. Persistent activation of cell p53 can lead to the expression of p21, an inhibitor of the cell cycle known as a cyclin-dependent kinase. This causes cells to cease dividing and leads to senescence, where cells can no longer increase. The accumulation of senescent cells in the aging kidney impairs kidney function by altering the microenvironment. As the number of senescent cells increases, the capacity of the kidney to recover from injury decreases, accelerating the progression of end-stage renal disease. This article review extensively explores the relationship between the p53/p21 pathway and cellular senescence within an aging kidney and the emerging therapeutic strategies that target it to overcome the impacts of cellular senescence on CKD.

Cellular senescence in Alzheimer's disease: from physiology to pathology

Alzheimer's disease (AD) is one of the most common neurodegenerative disorders, characterized by the accumulation of Aβ and abnormal tau hyperphosphorylation. Despite substantial efforts in development of drugs targeting Aβ and tau pathologies, effective therapeutic strategies for AD remain elusive. Recent attention has been paid to the significant role of cellular senescence in AD progression. Mounting evidence suggests that interventions targeting cellular senescence hold promise in improving cognitive function and ameliorating hallmark pathologies in AD. This narrative review provides a comprehensive summary and discussion of the physiological roles, characteristics, biomarkers, and commonly employed in vivo and in vitro models of cellular senescence, with a particular focus on various cell types in the brain, including astrocytes, microglia, oligodendrocyte precursor cells, neurons, and endothelial cells. The review further delves into factors influencing cellular senescence in AD and emphasizes the significance of targeting cellular senescence as a promising approach for AD treatment, which includes the utilization of senolytics and senomorphics.

Pan-cancer characterization of cellular senescence reveals its inter-tumor heterogeneity associated with the tumor microenvironment and prognosis

Cellular senescence (CS) is characterized by the irreversible cell cycle arrest and plays a key role in aging and diseases, such as cancer. Recent years have witnessed the burgeoning exploration of the intricate relationship between CS and cancer, with CS recognized as either a suppressing or promoting factor and officially acknowledged as one of the 14 cancer hallmarks. However, a comprehensive characterization remains absent from elucidating the divergences of this relationship across different cancer types and its involvement in the multi-facets of tumor development. Here we systematically assessed the cellular senescence of over 10,000 tumor samples from 33 cancer types, starting by defining a set of cancer-associated CS signatures and deriving a quantitative metric representing the CS status, called CS score. We then investigated the CS heterogeneity and its intricate relationship with the prognosis, immune infiltration, and therapeutic responses across different cancers. As a result, cellular senescence demonstrated two distinct prognostic groups: the protective group with eleven cancers, such as LIHC, and the risky group with four cancers, including STAD. Subsequent in-depth investigations between these two groups unveiled the potential molecular and cellular mechanisms underlying the distinct effects of cellular senescence, involving the divergent activation of specific pathways and variances in immune cell infiltrations. These results were further supported by the disparate associations of CS status with the responses to immuno- and chemo-therapies observed between the two groups. Overall, our study offers a deeper understanding of inter-tumor heterogeneity of cellular senescence associated with the tumor microenvironment and cancer prognosis.

Combined targeting of senescent cells and senescent macrophages: A new idea for integrated treatment of lung cancer

Lung cancer is one of the most common cancers worldwide and a leading cause of cancer-related deaths. Macrophages play a key role in the immune response and the tumour microenvironment. As an important member of the immune system, macrophages have multiple functions, including phagocytosis and clearance of pathogens, modulation of inflammatory responses, and participation in tissue repair and regeneration. In lung cancer, macrophages are considered to be the major cellular component of the tumor-associated inflammatory response and are closely associated with tumorigenesis, progression and metastasis. However, macrophages gradually undergo a senescence process with age and changes in pathological states. Macrophage senescence is an important change in the functional and metabolic state of macrophages and may have a significant impact on lung cancer development. In lung cancer, senescent macrophages interact with other cells in the tumor microenvironment (TME) by secreting senescence-associated secretory phenotype (SASP) factors, which can either promote the proliferation, invasion and metastasis of tumor cells or exert anti-tumor effects through reprogramming or clearance under specific conditions. Therefore, senescent macrophages are considered important potential targets for lung cancer therapy. In this paper, a systematic review of macrophages and their senescence process, and their role in tumors is presented. A variety of inhibitory strategies against senescent macrophages, including enhancing autophagy, inhibiting SASP, reducing DNA damage, and modulating metabolic pathways, were also explored. These strategies are expected to improve lung cancer treatment outcomes by restoring the anti-tumor function of macrophages.

Reprogramming cellular senescence in the tumor microenvironment augments cancer immunotherapy through multifunctional nanocrystals

Harnessing the immunogenic potential of senescent tumor cells provides an opportunity to remodel tumor microenvironment (TME) and boost antitumor immunity. However, this potential needs to be sophisticatedly wielded to avoid additional immunosuppressive capacity of senescent cells. Our study shows that blocking the JAK2/STAT3 pathway enhances immunogenic efficacy of Aurora kinase inhibitor alisertib (Ali)-induced senescence by reducing immunosuppressive senescence-associated secretory phenotype (SASP) while preserving immunogenic SASP. Hypothesizing that SASP reprogramming with Ali and JAK2 inhibitor ruxolitinib (Rux) will benefit cancer immunotherapy, we create nanoparticulate crystals (Ali-Rux) composed of Ali and Rux with a fully active pharmaceutical ingredient. Immunization with Ali-Rux-orchestrated senescent cells promotes stronger activation of antigen-presenting cells, enhancing antitumor immune surveillance. This approach remodels the TME by increasing CD8+ T cell and NK recruitment and activation while decreasing MDSCs. Combined with PD-L1 blockade, Ali-Rux elicits a durable antitumor immune response, suggesting the TME reshaping approach as a potential cancer immunotherapy.

The up-regulation of PD-L1 during boningmycin-induced senescence in human cancer cells depends on the activation of the JAK/STAT signaling pathway mediated by SASP

Therapy-induced senescence can regulate both the innate and adaptive immune systems, thereby affecting therapeutic efficacy. Bleomycin is a major component of combined chemotherapy regimens, utilized for the treatment of multiple tumors, whereas pulmonary toxicity severely restricts its clinical benefits. As a member of the bleomycin family, boningmycin (BON) exhibits potent anticancer activity with minimal pulmonary toxicity, making it a potential alternative to bleomycin. Low concentrations of BON can induce senescence, but the impact of BON-induced senescence on anticancer immunity remains unclear. This study investigates the effects of BON-induced senescence on PD-L1 expression and the underlying mechanisms in human cancer cells. Firstly, the elevation of PD-L1 protein during BON-induced senescence was confirmed by a senescence β-galactosidase staining assay, detection of the senescence-associated secretory phenotype (SASP), western blot and flow cytometry in human lung cancer NCI-H460 cells and breast cancer MDA-MB-231 cells. Subsequently, it was shown that the increase in PD-L1 protein is mediated by SASP, as evidenced by the use of conditional media, knockdown of cyclic GMP-AMP synthase and inhibition of stimulator of interferon genes. Ultimately, it was demonstrated that SASP-mediated PD-L1 up-regulation is dependent on the activation of the JAK/STAT pathway through the use of specific inhibitors and siRNAs. These findings clarify the impact of BON-induced senescence on PD-L1 expression and may contribute to the optimization of the therapeutic efficacy of bleomycin-related compounds and the clinical transformation of BON.

Cellular senescence in metastatic prostate cancer: A therapeutic opportunity or challenge (Review)

The treatment of patients with metastatic prostate cancer (PCa) is considered to be a long‑standing challenge. Conventional treatments for metastatic PCa, such as radical prostatectomy, radiotherapy and androgen receptor‑targeted therapy, induce senescence of PCa cells to a certain extent. While senescent cells can impede tumor growth through the restriction of cell proliferation and increasing immune clearance, the senescent microenvironment may concurrently stimulate the secretion of a senescence‑associated secretory phenotype and diminish immune cell function, which promotes PCa recurrence and metastasis. Resistance to established therapies is the primary obstacle in treating metastatic PCa as it can lead to progression towards an incurable state of disease. Therefore, understanding the molecular mechanisms that underly the progression of PCa is crucial for the development of novel therapeutic approaches. The present study reviews the phenomenon of treatment‑induced senescence in PCa, the dual role of senescence in PCa treatments and the mechanisms through which senescence promotes PCa metastasis. Furthermore, the present review discusses potential therapeutic strategies to target the aforementioned processes with the aim of providing insights into the evolving therapeutic landscape for the treatment of metastatic PCa.

Targeting senescence-associated secretory phenotypes to remodel the tumour microenvironment and modulate tumour outcomes

Tumour cell senescence can be induced by various factors, including DNA damage, inflammatory signals, genetic toxins, ionising radiation and nutrient metabolism. The senescence-associated secretory phenotype (SASP), secreted by senescent tumour cells, possesses the capacity to modulate various immune cells, including macrophages, T cells, natural killer cells and myeloid-derived suppressor cells, as well as vascular endothelial cells and fibroblasts within the tumour microenvironment (TME), and this modulation can result in either the promotion or suppression of tumorigenesis and progression. Exploring the impact of SASP on the TME could identify potential therapeutic targets, yet limited studies have dissected its functions. In this review, we delve into the causes and mechanisms of tumour cell senescence. We then concentrate on the influence of SASP on the tumour immune microenvironment, angiogenesis, extracellular matrix and the reprogramming of cancer stem cells, along with their associated tumour outcomes. Last, we present a comprehensive overview of the diverse array of senotherapeutics, highlighting their prospective advantages and challenge for the treatment of cancer patients. KEY POINTS: Senescence-associated secretory phenotype (SASP) secretion from senescent tumour cells significantly impacts cancer progression and biology. SASP is involved in regulating the remodelling of the tumour microenvironment, including immune microenvironment, vascular, extracellular matrix and cancer stem cells. Senotherapeutics, such as senolytic, senomorphic, nanotherapy and senolytic vaccines, hold promise for enhancing cancer treatment efficacy.

Nanoparticle delivery of innate immune agonists combined with senescence-inducing agents promotes T cell control of pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) has quickly risen to become the third leading cause of cancer-related death in the United States. This is in part because of its fibrotic tumor microenvironment (TME) that contributes to poor vascularization and immune infiltration and subsequent chemo- and immunotherapy failure. Here, we investigated an immunotherapy approach combining delivery of stimulator of interferon genes (STING) and Toll-like receptor 4 (TLR4) innate immune agonists by lipid-based nanoparticle (NP) coencapsulation with senescence-inducing RAS-targeted therapies, which can remodel the immune suppressive PDAC TME through the senescence-associated secretory phenotype. Treatment of transplanted and autochthonous PDAC mouse models with these regimens led to enhanced uptake of NPs by multiple cell types in the PDAC TME, induction of type I interferon and other proinflammatory signaling pathways, increased antigen presentation by tumor cells and antigen-presenting cells, and subsequent activation of both innate and adaptive immune responses. This two-pronged approach produced potent T cell-driven and type I interferon-mediated tumor regression and long-term survival in preclinical PDAC models dependent on both tumor and host STING activation. STING and TLR4-mediated type I interferon signaling was also associated with enhanced natural killer and CD8+ T cell immunity in human PDAC samples. Thus, combining localized immune agonist delivery with systemic tumor-targeted therapy can orchestrate a coordinated type I interferon-driven innate and adaptive immune response with durable antitumor efficacy against PDAC.

Measuring the impact of therapy-induced senescence on NK cell phenotypes in cancer

Cellular senescence is a damage-induced condition characterized by enduring cell cycle arrest and a heightened secretory profile known as the senescence-associated secretory phenotype (SASP). The SASP consists not only of release of inflammatory cytokines and chemokines that attract and activate a diverse repertoire of innate and adaptive immune cells, but also the upregulation of immunomodulatory cell surface molecules that promote immune clearance of senescent cells. Natural Killer (NK) cells are particularly adept at sensing and eliminating senescent cells. In the setting of cancer, commonly administered cytotoxic and cytostatic therapies can elicit senescence and in turn reactivate NK cell immune surveillance against tumors. Here, we detail a series of in vivo, ex vivo, and in vitro assays to assess the impact of therapy-induced senescence on NK cell phenotypes, including their activation, exhaustion, migration, and killing capacity in the context of pancreatic cancer. Importantly, this methodology can be adapted to investigate NK cell biology across various disease states and treatment modalities and help inform NK cell-based immunotherapies for cancer.

Therapy-Induced Cellular Senescence: Potentiating Tumor Elimination or Driving Cancer Resistance and Recurrence?

Cellular senescence has been increasingly recognized as a hallmark of cancer, reflecting its association with aging and inflammation, its role as a response to deregulated proliferation and oncogenic stress, and its induction by cancer therapies. While therapy-induced senescence (TIS) has been linked to resistance, recurrence, metastasis, and normal tissue toxicity, TIS also has the potential to enhance therapy response and stimulate anti-tumor immunity. In this review, we examine the Jekyll and Hyde nature of senescent cells (SnCs), focusing on how their persistence while expressing the senescence-associated secretory phenotype (SASP) modulates the tumor microenvironment through autocrine and paracrine mechanisms. Through the SASP, SnCs can mediate both resistance and response to cancer therapies. To fulfill the unmet potential of cancer immunotherapy, we consider how SnCs may influence tumor inflammation and serve as an antigen source to potentiate anti-tumor immune response. This new perspective suggests treatment approaches based on TIS to enhance immune checkpoint blockade. Finally, we describe strategies for mitigating the detrimental effects of senescence, such as modulating the SASP or targeting SnC persistence, which may enhance the overall benefits of cancer treatment.

Integrative analyses of genes associated with oxidative stress and cellular senescence in triple-negative breast cancer

Background

Oxidative stress and cellular senescence (OSCS) have great impacts on the occurrence and progression of triple-negative breast cancer (TNBC). This study was intended to construct a prognostic model based on oxidative stress and cellular senescence related difference expression genes (OSCSRDEGs) for TNBC.

Methods

The Cancer Genome Atlas (TCGA) databases and two Gene Expression Omnibus (GEO) databases were used to identify OSCSRDEGs. The relationship between OSCSRDEGs and immune infiltration was examined using single-sample gene-set enrichment analysis (ssGSEA), ESTIMATE, and the CIBERSORT algorithm. Least absolute shrinkage and selection operator (LASSO) regression analyses, Cox regression and Kaplan-Meier analysis were employed to construct a prognostic model. Receiver operating characteristic (ROC) curves, nomograms, and decision curve analysis (DCA) were used to evaluate the prognostic efficacy. Gene Set Enrichment Analysis (GSEA) Gene Ontology (GO), and Kyoto Encyclopedia of Genes and Genomes (KEGG) were utilized to explore the potential functions and mechanism.

Results

A comprehensive analysis identified a total of 27 OSCSRDEGs, out of which 15 genes selected for development of a prognostic model. A high degree of statistical significance was observed for the riskscores derived from this model to accurately predict TNBC Overall survival. The decision curve analysis (DCA) and ROC curve analysis further confirmed the superior accuracy of the OSCSRDEGs prognostic model in predicting efficacy. Notably, the nomogram analysis highlighted that DMD exhibited the highest utility within the model. In comparison between high and low OSCScore groups, the infiltration abundance of immune cells was statistically different in the TCGA-TNBC dataset.

Conclusion

These studies have effectively identified four essential OSCSRDEGs (CFI, DMD, NDRG2, and NRP1) and meticulously developed an OSCS-associated prognostic model for individuals diagnosed with TNBC. These discoveries have the potential to significantly contribute to the comprehension of the involvement of OSCS in TNBC.

Integrated analysis of single-cell and bulk RNA sequencing data reveals a cellular senescence-related signature in hepatocellular carcinoma

The mortality of hepatocellular carcinoma (HCC) is on the rise globally, particularly in the Western world, with etiology gradually shifting from virus-related liver diseases to metabolic disorders such as non-alcoholic fatty liver disease. Early detection of HCC is challenging, and effective prognostic indicators are currently lacking, urgently necessitating reliable markers to assist in treatment planning and clinical management. Here, we introduce hepatocellular carcinoma senescence genes (HSG) to assess cellular senescence in HCC and devise a hepatocellular carcinoma senescence score (HSS) for prognostic prediction. Higher HSS levels signify poorer prognosis and increased tumor proliferation activity. Additionally, we observe alterations in the tumor immune microenvironment with higher HSS levels, such as increased infiltration of Treg, potentially providing a basis for immunotherapy. Furthermore, we identify key genes, such as PTTG1, within the senescence gene set and demonstrate their regulatory roles in HCC cells and Treg through experimentation. In summary, we establish a scoring system based on hepatocellular carcinoma senescence genes for prognostic prediction in HCC, potentially offering guidance for clinical treatment planning.

Targeting cellular senescence as a therapeutic vulnerability in gastric cancer

AIMS

Cellular senescence (CS) represents an intracellular defense mechanism responding to stress signals and can be leveraged as a "vulnerability" in cancer treatment. This study aims to construct a CS atlas for gastric cancer (GC) and uncover potential therapeutics for GC patients.

MATERIALS AND METHODS

38 senescence-associated regulators with prognostic significance in GC were obtained from the CellAge database to construct Gastric cancer-specific Senescence Score (GSS). Using eXtreme Sum algorism, GSS-based drug repositioning was conducted to identify drugs that could antagonize GSS in CMap database. In vitro experiments were conducted to test the effect of combination of palbociclib and exisulind in eliminating GC cells.

KEY FINDINGS

Patients with high GSS exhibited CS-related features, such as CS markers upregulation, adverse clinical outcomes and hypomethylation status. scRNA-seq data showed malignant cells with high GSS exhibited enhanced senescence state and more immunosuppressive signals such as PVR-CD96 compared with malignant cells with low GSS. In addition, the GSS-High cancer associated fibroblasts might secrete cytokines and chemokines such as IL-6, CXCL1, CXCL12, and CCL2 to from an immunosuppressive microenvironment, and GSS could serve as an indicator for immunotherapy resistance. Exisulind exhibited the greatest potential to reverse GSS. In vitro experiments demonstrated that exisulind could induce apoptosis and suppress the proliferation of palbociclib-induced senescent GC cells.

SIGNIFICANCE

Overall, GSS offers a framework for better understanding of correlation between senescence and GC, which might provide new insights into the development of novel therapeutics in GC.

Ageing microenvironment mediates lymphocyte carcinogenesis and lymphoma drug resistance: From mechanisms to clinical therapy (Review)

Cellular senescence has a complex role in lymphocyte carcinogenesis and drug resistance of lymphomas. Senescent lymphoma cells combine with immunocytes to create an ageing environment that can be reprogrammed with a senescence‑associated secretory phenotype, which gradually promotes therapeutic resistance. Certain signalling pathways, such as the NF‑κB, Wnt and PI3K/AKT/mTOR pathways, regulate the tumour ageing microenvironment and induce the proliferation and progression of lymphoma cells. Therefore, targeting senescence‑related enzymes or their signal transduction pathways may overcome radiotherapy or chemotherapy resistance and enhance the efficacy of relapsed/refractory lymphoma treatments. Mechanisms underlying drug resistance in lymphomas are complex. The ageing microenvironment is a novel factor that contributes to drug resistance in lymphomas. In terms of clinical translation, some senolytics have been used in clinical trials on patients with relapsed or refractory lymphoma. Combining immunotherapy with epigenetic drugs may achieve better therapeutic effects; however, senescent cells exhibit considerable heterogeneity and lymphoma has several subtypes. Extensive research is necessary to achieve the practical application of senolytics in relapsed or refractory lymphomas. This review summarises the mechanisms of senescence‑associated drug resistance in lymphoma, as well as emerging strategies using senolytics, to overcome therapeutic resistance in lymphoma.

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.

Stimulator of interferon genes mediated immune senescence reveals the immune microenvironment and prognostic characteristics of bladder cancer

Background

Studies have shown that the stimulator of interferon genes (STING) is critical in tumorigenesis, and development. This study aimed to investigate the immune profile and prognostic significance of STING-mediated immune senescence in bladder cancer (BLCA).

Methods

We identified differential genes between tumor and normal tissue based on the Cancer Genome Atlas database, and used consensus clustering to identify BLCA subtypes. The genes most associated with overall survival were screened by further analysis and used to construct risk models. Then, comparing the immune microenvironment, tumor mutational load (TMB), and microsatellite instability (MSI) scores between different risk groups. Eventually, a nomogram was constructed based on clinical information and risk scores. The model was validated using receiver operating curves (ROC) and calibration plots.

Results

We identified 160 differential genes, including 13 genes most associated with prognosis. Three subtypes of bladder cancer with different clinical and immunological features were identified. Immunotherapy was more likely to benefit the low-risk group, which had higher TMB and MSI scores. The nomogram was found to be highly predictive based on ROC analysis and calibration plots.

Conclusion

The risk model and nomogram not only predict the prognosis of BLCA patients but also can guide the treatment.

Neutrophil-activating secretome characterizes palbociclib-induced senescence of breast cancer cells

Senescent cells have a profound impact on the surrounding microenvironment through the secretion of numerous bioactive molecules and inflammatory factors. The induction of therapy-induced senescence by anticancer drugs is known, but how senescent tumor cells influence the tumor immune landscape, particularly neutrophil activity, is still unclear. In this study, we investigate the induction of cellular senescence in breast cancer cells and the subsequent immunomodulatory effects on neutrophils using the CDK4/6 inhibitor palbociclib, which is approved for the treatment of breast cancer and is under intense investigation for additional malignancies. Our research demonstrates that palbociclib induces a reversible form of senescence endowed with an inflammatory secretome capable of recruiting and activating neutrophils, in part through the action of interleukin-8 and acute-phase serum amyloid A1. The activation of neutrophils is accompanied by the release of neutrophil extracellular trap and the phagocytic removal of senescent tumor cells. These findings may be relevant for the success of cancer therapy as neutrophils, and neutrophil-driven inflammation can differently affect tumor progression. Our results reveal that neutrophils, as already demonstrated for macrophages and natural killer cells, can be recruited and engaged by senescent tumor cells to participate in their clearance. Understanding the interplay between senescent cells and neutrophils may lead to innovative strategies to cope with chronic or tumor-associated inflammation.

Development of a novel senescence-related gene signature to predict clinical outcomes, immune landscape, and chemotherapeutic sensitivity in oral squamous cell carcinoma

BACKGROUND

Cellular senescence significantly associates with tumor initiation, progression, and therapeutic response across multiple cancers. Here, we sought to develop a novel senescence-related genes (SRGs)-derived signature for oral squamous cell carcinoma (OSCC) prognostication and therapeutic response prediction.

METHODS

OSCC-specific SRG prognostic signature was established with univariate Cox regression, Kaplan-Meier survival, and LASSO-penalized multivariate Cox regression analyses. A SRG nomogram integrating this signature and selected clinicopathological parameters were constructed by multivariate Cox regression. SiRNA-mediated gene knockdown was exploited to validate its function in vitro. The utilities of SRG signature in predicting immune status and chemotherapeutic sensitivities were analyzed.

RESULTS

The prognostic performance of SRG signature/nomogram was satisfactory in multiple independent cohorts. CDK1 knockdown induced senescence phenotype in vitro. Moreover, SRG signature scores negatively correlated with tumor-infiltrating immune cells and associated with multiple chemotherapeutic drug sensitivities.

CONCLUSIONS

Our results established SRG-derived signature/nomogram as powerful predictors for prognosis and chemotherapeutic response for OSCC.

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.

Advances in Making Cancer Mouse Models More Accessible and Informative through Non-Germline Genetic Engineering

Genetically engineered mouse models (GEMMs) allow for modeling of spontaneous tumorigenesis within its native microenvironment in mice and have provided invaluable insights into mechanisms of tumorigenesis and therapeutic strategies to treat human disease. However, as their generation requires germline manipulation and extensive animal breeding that is time-, labor-, and cost-intensive, traditional GEMMs are not accessible to most researchers, and fail to model the full breadth of cancer-associated genetic alterations and therapeutic targets. Recent advances in genome-editing technologies and their implementation in somatic tissues of mice have ushered in a new class of mouse models: non-germline GEMMs (nGEMMs). nGEMM approaches can be leveraged to generate somatic tumors de novo harboring virtually any individual or group of genetic alterations found in human cancer in a mouse through simple procedures that do not require breeding, greatly increasing the accessibility and speed and scale on which GEMMs can be produced. Here we describe the technologies and delivery systems used to create nGEMMs and highlight new biological insights derived from these models that have rapidly informed functional cancer genomics, precision medicine, and immune oncology.

The senescence journey in cancer immunoediting

Cancer progression is continuously controlled by the immune system which can identify and destroy nascent tumor cells or inhibit metastatic spreading. However, the immune system and its deregulated activity in the tumor microenvironment can also promote tumor progression favoring the outgrowth of cancers capable of escaping immune control, in a process termed cancer immunoediting. This process, which has been classified into three phases, i.e. "elimination", "equilibrium" and "escape", is influenced by several cancer- and microenvironment-dependent factors. Senescence is a cellular program primed by cells in response to different pathophysiological stimuli, which is based on long-lasting cell cycle arrest and the secretion of numerous bioactive and inflammatory molecules. Because of this, cellular senescence is a potent immunomodulatory factor promptly recruiting immune cells and actively promoting tissue remodeling. In the context of cancer, these functions can lead to both cancer immunosurveillance and immunosuppression. In this review, the authors will discuss the role of senescence in cancer immunoediting, highlighting its context- and timing-dependent effects on the different three phases, describing how senescent cells promote immune cell recruitment for cancer cell elimination or sustain tumor microenvironment inflammation for immune escape. A potential contribution of senescent cells in cancer dormancy, as a mechanism of therapy resistance and cancer relapse, will be discussed with the final objective to unravel the immunotherapeutic implications of senescence modulation in cancer.

Mechanisms of carboplatin- and paclitaxel-dependent induction of premature senescence and pro-cancerogenic conversion of normal peritoneal mesothelium and fibroblasts

Carboplatin (CPT) and paclitaxel (PCT) are the optimal non-surgical treatment of epithelial ovarian cancer (EOC). Although their growth-restricting influence on EOC cells is well known, their impact on normal peritoneal cells, including mesothelium (PMCs) and fibroblasts (PFBs), is poorly understood. Here, we investigated whether, and if so, by what mechanism, CPT and PCT induce senescence of omental PMCs and PFBs. In addition, we tested whether PMC and PFB exposure to the drugs promotes the development of a pro-cancerogenic phenotype. The results showed that CPT and PCT induce G2/M growth arrest-associated senescence of normal peritoneal cells and that the strongest induction occurs when the drugs act together. PMCs senesce telomere-independently with an elevated p16 level and via activation of AKT and STAT3. In PFBs, telomeres shorten along with an induction of p21 and p53, and their senescence proceeds via the activation of ERK1/2. Oxidative stress in CPT + PCT-treated PMCs and PFBs is extensive and contributes causatively to their premature senescence. Both PMCs and PFBs exposed to CPT + PCT fuel the proliferation, migration, and invasion of established (A2780, OVCAR-3, SKOV-3) and primary EOCs, and this activity is linked with an overproduction of multiple cytokines altering the cancer cell transcriptome and controlled by p38 MAPK, NF-κB, STAT3, Notch1, and JAK1. Collectively, our findings indicate that CPT and PCT lead to iatrogenic senescence of normal peritoneal cells, which paradoxically and opposing therapeutic needs alters their phenotype towards pro-cancerogenic. It cannot be excluded that these adverse outcomes of chemotherapy may contribute to EOC relapse in the case of incomplete tumor eradication and residual disease initiation. © 2023 The Pathological Society of Great Britain and Ireland.

Biological effects of IL-21 on immune cells and its potential for cancer treatment

Interleukin-21 (IL-21), a member of the IL-2 cytokine family, is one of the most important effector and messenger molecules in the immune system. Produced by various immune cells, IL-21 has pleiotropic effects on innate and adaptive immune responses via regulation of natural killer, T, and B cells. An anti-tumor role of IL-21 has also been reported in the literature, as it may support cell proliferation or on the contrary induce growth arrest or apoptosis of the tumor cell. Anti-tumor effect of IL-21 enhances when combined with other agents that target tumor cells, immune regulatory circuits, or other immune-enhancing molecules. Therefore, understanding the biology of IL-21 in the tumor microenvironment (TME) and reducing its systemic toxic and side effects is crucial to ensure the maximum benefits of anti-tumor treatment strategies. In this review, we provide a comprehensive overview on the biological functions, roles in tumors, and the recent advances in preclinical and clinical research of IL-21 in tumor immunotherapy.

Protocol for examining the capability of senescent tumor cells to stimulate murine bone-marrow-derived dendritic cells by flow cytometry

Therapy-induced senescence (TIS) may contribute to therapy resistance; however, evidence also suggests that senescent cells (SnCs) may promote anti-tumor immunity. Here, we present a protocol for examining the capability of TIS to stimulate type 1 conventional CD103+ dendritic cells (DCs). We describe steps for isolating and differentiating CD103+ DCs from murine bone marrow, inducing senescence in murine colon carcinoma cell line CT26, and coculturing DCs with SnCs. We then detail the flow cytometric analysis of DC maturation and activation. For complete details on the use and execution of this protocol, please refer to Liu et al. (2022)1 and Liu et al. (2023).2.

HELLS modulates the stemness of intrahepatic cholangiocarcinoma through promoting senescence-associated secretory phenotype

The senescence-associated secretory phenotype (SASP) is closely associated with the tumorigenesis and progression of intrahepatic cholangiocarcinoma (ICC). However, it remains unclear its relation to stemness of ICC. In the study, the stemness indices of ICC were calculated using one-class linear regression (OCLR) and single-sample gene set enrichment analysis (ssGSEA) algorithms. A total of 14 senescence-related stemness genes (SRSGs) were identified using Pearson correlation analysis in ICC. Subsequently, a SRSGs-related classification was established using a consensus clustering for ICC. Different types of ICC exhibit distinct prognosis, immunity, metabolisms, and oncogenic signatures. Additionally, we constructed a risk score model for ICC using principal component analysis (PCA). The risk score was positively correlated with stemness, immune infiltration, metabolisms and oncogenic signatures, but negatively with prognosis in ICC. Patients with a high risk score may respond well to immunotherapy. Furthermore, we employed 3D fibrin gels to select tumor-repopulating cells (TRC) with stemness features. We found that HELLS, belonging to the 14 SRSGs, was up-regulated in ICC-TRC. And silencing HELLS significantly reduced the colony size, inhibited migration and invasion, and attenuated SASP in ICC-TRC. In summary, we provided a novel classification and risk score for ICC and uncovered a molecular mechanism via which CSLCs could obtain an active SASP.

Neutrophil extracellular traps and long COVID

Post-acute COVID-19 sequelae, commonly known as long COVID, encompasses a range of systemic symptoms experienced by a significant number of COVID-19 survivors. The underlying pathophysiology of long COVID has become a topic of intense research discussion. While chronic inflammation in long COVID has received considerable attention, the role of neutrophils, which are the most abundant of all immune cells and primary responders to inflammation, has been unfortunately overlooked, perhaps due to their short lifespan. In this review, we discuss the emerging role of neutrophil extracellular traps (NETs) in the persistent inflammatory response observed in long COVID patients. We present early evidence linking the persistence of NETs to pulmonary fibrosis, cardiovascular abnormalities, and neurological dysfunction in long COVID. Several uncertainties require investigation in future studies. These include the mechanisms by which SARS-CoV-2 brings about sustained neutrophil activation phenotypes after infection resolution; whether the heterogeneity of neutrophils seen in acute SARS-CoV-2 infection persists into the chronic phase; whether the presence of autoantibodies in long COVID can induce NETs and protect them from degradation; whether NETs exert differential, organ-specific effects; specifically which NET components contribute to organ-specific pathologies, such as pulmonary fibrosis; and whether senescent cells can drive NET formation through their pro-inflammatory secretome in long COVID. Answering these questions may pave the way for the development of clinically applicable strategies targeting NETs, providing relief for this emerging health crisis.

A comprehensive pan-cancer analysis of CDH5 in immunological response

Background

Cadherin 5 (CDH5) functions critically in maintaining cell adhesion and integrity of endothelial and vascular cells. The expression of CDH5 is abnormal in tumor cells, which may have great potential to serve as a new immune checkpoint. The current pan-cancer analysis was performed to better understand the role of CDH5 in tumor.

Methods

The clinical significance and immunological function of CDH5 in pan-cancers were comprehensively analyzed based on the correlations between CDH5 and clinicopathologic features, prognosis values, tumor mutation burden (TMB), microsatellite instability (MSI), immune cells infiltration and immune response genes using 33 datasets from The Cancer Genome Atlas (TCGA). We further confirmed the expression of CDH5 in bladder cancer (BCa) tissues and cell lines. The CD8+ T cells were screened from peripheral blood of healthy controls and activated. BCa cell-CD8+ T cell co-culture assay and ELISA assay were carried out to verify the immunological function of CDH5.

Results

The expression of CDH5 was down-regulated in 8 types of tumors including in BCa but up-regulated in 4 types of tumors. CDH5 was significantly correlated with tumor stage in 6 types of tumors. In addition, CDH5 was positively or negatively correlated with tumor prognosis. Furthermore, CDH5 was closely associated with TMB in 15 types of tumors and with MSI in 9 types of tumors. KEGG-GSEA and Hallmarks-GSEA analyses results indicated that CDH5 was positively related to immune response in most tumor types. In many tumors, CDH5 showed a positive correlation with immune cell infiltration. Enrichment analyses demonstrated that CDH5 was significantly related to the expression of many immunomodulators and chemokines. Further experiments showed that CDH5 was low-expressed in BCa tissues and cell lines in comparison to adjacent normal tissues and normal urothelial cell line, but it was positively associated with a better prognosis of BCa patients. The results of in vitro co-culture assay and ELISA assay demonstrated that CDH5 could promote the function of CD8+ T cells in TME of BCa.

Conclusion

In summary, CDH5 was positively associated with a favorable prognosis and effective immune response in tumors, showing a great potential to serve as a novel tumor biomarker and immune checkpoint.

Nanoparticle delivery of innate immune agonists combines with senescence-inducing agents to mediate T cell control of pancreatic cancer

Pancreatic ductal adenocarcinoma has quickly risen to become the 3rd leading cause of cancer-related death. This is in part due to its fibrotic tumor microenvironment (TME) that contributes to poor vascularization and immune infiltration and subsequent chemo- and immunotherapy failure. Here we investigated an innovative immunotherapy approach combining local delivery of STING and TLR4 innate immune agonists via lipid-based nanoparticles (NPs) co-encapsulation with senescence-inducing RAS-targeted therapies that can remodel the immune suppressive PDAC TME through the senescence-associated secretory phenotype. Treatment of transplanted and autochthonous PDAC mouse models with these regimens led to enhanced uptake of NPs by multiple cell types in the PDAC TME, induction of type I interferon and other pro-inflammatory signaling, increased antigen presentation by tumor cells and antigen presenting cells, and subsequent activation of both innate and adaptive immune responses. This two-pronged approach produced potent T cell-driven and Type I interferon-dependent tumor regressions and long-term survival in preclinical PDAC models. STING and TLR4-mediated Type I interferon signaling were also associated with enhanced NK and CD8+ T cell immunity in human PDAC. Thus, combining localized immune agonist delivery with systemic tumor-targeted therapy can synergize to orchestrate a coordinated innate and adaptive immune assault to overcome immune suppression and activate durable anti-tumor T cell responses against PDAC.

Cellular senescence in glioma

INTRODUCTION

Glioma is the most common primary brain tumor and is often associated with treatment resistance and poor prognosis. Standard treatment typically involves radiotherapy and temozolomide-based chemotherapy, both of which induce cellular senescence-a tumor suppression mechanism.

DISCUSSION

Gliomas employ various mechanisms to bypass or escape senescence and remain in a proliferative state. Importantly, senescent cells remain viable and secrete a large number of factors collectively known as the senescence-associated secretory phenotype (SASP) that, paradoxically, also have pro-tumorigenic effects. Furthermore, senescent cells may represent one form of tumor dormancy and play a role in glioma recurrence and progression.

CONCLUSION

In this article, we delineate an overview of senescence in the context of gliomas, including the mechanisms that lead to senescence induction, bypass, and escape. Furthermore, we examine the role of senescent cells in the tumor microenvironment and their role in tumor progression and recurrence. Additionally, we highlight potential therapeutic opportunities for targeting senescence in glioma.