Cellular Senescence Is Immunogenic and Promotes Antitumor Immunity

Hyperdifferentiated murine melanoma cells promote adaptive anti-tumor immunity but activate the immune checkpoint system

Accumulating evidence suggests that phenotype switching of cancer cells is essential for therapeutic resistance. However, the immunological characteristics of drug-induced phenotype-switching melanoma cells (PSMCs) are unknown. We investigated PSMC elimination by host immunity using hyperdifferentiated melanoma model cells derived from murine B16F10 melanoma cells. Exposure of B16F10 cells to staurosporine induced a hyperdifferentiated phenotype associated with transient drug tolerance. Staurosporine-induced hyperdifferentiated B16F10 (sB16F10) cells expressed calreticulin on their surface and were phagocytosed efficiently. Furthermore, the inoculation of mice with sB16F10 cells induced immune responses against tumor-derived antigens. Despite the immunogenicity of sB16F10 cells, they activated the PD-1/PD-L1 immune checkpoint system and strongly resisted T cell-mediated tumor destruction. However, in vivo treatment with immune checkpoint inhibitors successfully eliminated the tumor. Thus, hyperdifferentiated melanoma cells have conflicting immunological properties - enhanced immunogenicity and immune evasion. Inhibiting the ability of PSMCs to evade T cell-mediated elimination might lead to complete melanoma eradication.

Senescence profiling of monoclonal gammopathies reveals paracrine senescence as a crucial defense against disease progression

Multiple myeloma (MM) is a plasma cell (PC) malignancy that is preceded by monoclonal gammopathy of undetermined significance (MGUS) and/or smoldering multiple myeloma (SMM). MGUS and SMM PCs exhibit the same primary oncogenic abnormalities as MM but lack the end-organ damage that defines proliferative disease, suggesting that clonal PCs in these precursor conditions could exhibit senescence or senescence-like growth arrest. Herein we identified monoclonal gammopathy patient-derived PCs that exhibit senescence features and found that senescent PCs were significantly increased in MGUS patients compared to SMM or MM. Spatial analysis of senescent PCs in stable MGUS and SMM patient biopsies demonstrated the activation of local paracrine senescence in the bone marrow microenvironment. Stable MGUS and SMM patients also exhibited disease-specific senescence-associated secretory phenotype (SASP) signatures that significantly correlated with PC burden and clonal antibody. In contrast, progressing MGUS, SMM, and new MM patients lacked local paracrine senescence responses and robust activation of disease specific SASP signatures. Overall, these data suggest that failure to activate tumor-specific paracrine senescence responses is key to disease progression in monoclonal gammopathies.

Therapy-induced senescence is a transient drug resistance mechanism in breast cancer

BACKGROUND

Therapy-induced senescence (TIS) is considered a permanent cell cycle arrest following DNA-damaging treatments; however, its irreversibility has recently been challenged. Here, we demonstrate that escape from TIS is universal across breast cancer cells. Moreover, TIS provides a reversible drug resistance mechanism that ensures the survival of the population, and could contribute to relapse.

METHODS

TIS was induced in four different breast cancer cell line with high-dose chemotherapy and cultured until cells escaped TIS. Parental, TIS and repopulating cells were analyzed by bulk and single-cell RNA sequencing and surface proteomics. A genetically engineered mouse model of triple-negative breast cancer was used to prove why current senolytics cannot overcome TIS in tumors.

RESULTS

Screening the toxicity of a diverse panel of FDA-approved anticancer drugs revealed that TIS meditates resistance to half of these compounds, despite their distinct mechanism of action. Bulk and single-cell RNA sequencing, along with surface proteome analysis, showed that while parental and repopulating cells are almost identical, TIS cells are significantly different from both, highlighting their transient nature. Furthermore, investigating dozens of known drug resistance mechanisms offered no explanation for this unique drug resistance pattern. Additionally, TIS cells expressed a gene set associated with immune evasion and a potential KRAS-driven escape mechanism from TIS.

CONCLUSION

Our results reveal that TIS, as a transient drug resistance mechanism, could contribute to overcome the immune response and to relapse by reverting to a proliferative stage.

TFDP1 drives triple-negative breast Cancer development through senescence suppression and serves as a therapeutic target for topotecan

Triple-negative breast cancer (TNBC) constitutes the molecular subtype exhibiting the poorest prognosis. Targeted therapy emerges as a pivotal strategy to enhance the clinical outcomes of individuals with TNBC. Identifying targets and corresponding therapeutic agents is essential for reducing TNBC-related mortality. Topotecan, a chemotherapeutic agent approved for treating metastatic breast cancer, remains under investigation regarding its specific targets and molecular mechanisms in TNBC. Data procured from CRISPR/Cas9 library screenings showed that TFDP1 may be a therapeutic target in TNBC, and the L1000FWD database suggested that TFDP1 serves as a potential target of topotecan. The overexpression of TFDP1 was observed in TNBC tissues, correlating with poorer prognosis. Knockdown of TFDP1 inhibited the cell growth, clonal expansion, and tumorigenicity of TNBC cells. Mechanistically, TFDP1 inhibited cellular senescence in TNBC cells. In vitro experiments demonstrated that topotecan inhibited TNBC cell growth and promoted cellular senescence, counteracting the effects of TFDP1 overexpression on TNBC cells. These findings suggest that topotecan impedes TNBC cell growth by targeting TFDP1. This interaction provides valuable insights into the molecular mechanisms governing TNBC cell senescence, presenting TFDP1 as a potential therapeutic target. Combining topotecan with senolytic therapies may offer a promising strategy for TNBC treatment.

Splicing factor SF3B4 acts as a switch in cancer cell senescence by regulating p21 mRNA stability

SF3B4, a splicing factor known to regulate mRNA expression and function, is upregulated in various cancers. Despite its potential significance, the mechanisms through which SF3B4 regulates nonsense-mediated mRNA decay (NMD) and cancer cell senescence remain poorly understood. This study explores the underlying mechanisms by which SF3B4 modulates mRNA stability through the NMD pathway and elucidates its role in switching cancer cells between growth and senescence. We demonstrate that SF3B4 deficiency leads to decreased cancer cell proliferation, increased senescence-associated β-galactosidase (SA-β-Gal) activity, p53-independent upregulation of p21 expression, and ultimate induction of cell senescence. We further show that SF3B4 recruits essential NMD factors, including UPF1, MAGOH, and RNPS1, which facilitate mRNA decay of the crucial senescence regulator, p21. Conversely, SF3B4 depletion results in the dissociation of these factors from the 3'UTR of p21 mRNA, thereby enhancing its stability. Collectively, our results suggest that SF3B4 critically regulates p21 expression at the post-transcriptional level, providing insights into the novel role of SF3B4 in regulating p21 mRNA stability, interacting with key NMD factors, and modulating cancer cell senescence.

Regulation of cellular senescence in tumor progression and therapeutic targeting: mechanisms and pathways

Cellular senescence, a stable state of cell cycle arrest induced by various stressors or genomic damage, is recognized as a hallmark of cancer. It exerts a context-dependent dual role in cancer initiation and progression, functioning as a tumor suppressor and promoter. The complexity of senescence in cancer arises from its mechanistic diversity, potential reversibility, and heterogeneity. A key mediator of these effects is the senescence-associated secretory phenotype (SASP), a repertoire of bioactive molecules that influence tumor microenvironment (TME) remodeling, modulate cancer cell behavior, and contribute to therapeutic resistance. Given its intricate role in cancer biology, senescence presents both challenges and opportunities for therapeutic intervention. Strategies targeting senescence pathways, including senescence-inducing therapies and senolytic approaches, offer promising avenues for cancer treatment. This review provides a comprehensive analysis of the regulatory mechanisms governing cellular senescence in tumors. We also discuss emerging strategies to modulate senescence, highlighting novel therapeutic opportunities. A deeper understanding of these processes is essential for developing precision therapies and improving clinical outcomes.

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.

The CDK12-BRCA1 signaling axis mediates dinaciclib-associated radiosensitivity through p53-mediated cellular senescence

Pan-cyclin-dependent-kinase (CDK) inhibitors are a new class of targeted therapies that can act on multiple CDKs, with dinaciclib being one of the most promising compounds. Although used as a monotherapy, an interesting approach could be to combine it with radiotherapy. Here, we show that dinaciclib increases radiosensitivity in some experimental models of lung and colon cancer (A549 or HCT 116) but not in others (H1299 or HT-29). Dinaciclib did not alter serine-protein kinase ATM signalling or cell cycle profiling after ionising-radiation exposure, which have been described for other CDK inhibitors. Interestingly, in terms of apoptosis, although the combination renders a clear increase, no potentiation of the ionising-radiation-induced apoptosis was observed. Mechanistically, inhibition of CDK12 by dinaciclib diminishes BRCA1 expression, which decreases homologous recombination (HR) and probably promotes the nonhomologous end joining repair process (NHEJ), which ultimately promotes the induction of ionising-radiation-associated cellular senescence in a TP53-dependent manner, explaining the lack of effect observed in some experimental models. In conclusion, our report proposes a molecular mechanism, based on the signalling axis CDK12-BRCA1, involved in this newly identified therapeutic effect of dinaciclib, although other players implicated in HR should not be discarded. In addition, our data provide a rationale for more selective and personalised chemo/radiotherapy treatment according to the genetic background of the tumour.

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.

The key pathways and genes related to oncolytic Newcastle disease virus-induced phenotypic changes in ovarian cancer cells

The poor prognosis and high recurrence rate of ovarian cancer highlight the urgent need to develop new therapeutic strategies. Oncolytic Newcastle disease virus (NDV) can kill cancer cells directly and regulate innate and adaptive immunity. In this study, ovarian cancer cells infected with or without velogenic NDV-BJ were subjected to a CCK-8 assay for detecting cell proliferation, flow cytometry for detecting the cell cycle and apoptosis, and wound healing and transwell assays for detecting cell migration and invasion. Transcriptomic sequencing was conducted to identify the differentially expressed genes (DEGs). GO and KEGG enrichment analyses were performed to explore the mechanism underlying the oncolytic effect of NDV on ovarian cancer cells. The results showed that infection with NDV inhibited ovarian cancer cell proliferation, migration, and invasion; disrupted the cell cycle; and promoted apoptosis. Compared with those in negative control cells, the numbers of upregulated and downregulated genes in ovarian cancer cells infected with NDV were 1,499 and 2,260, respectively. Thirteen KEGG pathways related to cell growth and death, cell mobility, and signal transduction were significantly enriched. Among these pathways, 48 DEGs, especially SESN2, HLA B/C/E, GADD45B, and RELA, that may be involved in the oncolytic process were screened, and qPCR analysis verified the reliability of the transcription data. This study discovered some key pathways and genes related to oncolytic NDV-induced phenotypic changes in ovarian cancer cells, which will guide our future research directions and help further explore the specific mechanisms by which infection with NDV suppresses ovarian cancer development.

Targeting senescence with radioactive 223Ra/Ba SAzymes enables senolytics-unlocked One-Two punch strategy to boost anti-tumor immunotherapy

Senescent cells are characterized by a persistent cessation of their cell cycle, rendering them valuable targets for anti-tumor strategies in cancer treatment. Numerous studies have explored induced senescence as a promising approach in tumor therapy. Nevertheless, these treatments often come with drawbacks, including adverse side effects and weaker senescence-inducing effects. To address these challenges, we synthesized 223Ra/Ba single-atom nanozyme (SAzyme), wherein Ba SAzyme acts concurrently as a carrier for 223RaCl2, facilitating targeted delivery and minimizing side effects. The 223Ra/Ba SAzyme complex enhances various enzyme-mimicking functions, including catalase (CAT) and peroxidase (POD) activities. Importantly, 223Ra/Ba SAzyme induces cellular senescence and boost anti-tumor immunity. The persistent presence of a senescence-associated secretory phenotype (SASP) in the tumor microenvironment presents risks of immune suppression and tumor recurrence, which can be effectively mitigated by senolytics. As a result, 223Ra/Ba SAzyme were combined with anti-PD-L1 checkpoint blockade to achieve a one-two punch therapy, wherein 223Ra/Ba SAzyme exploits senescence followed by anti-PD-L1 therapy to eradicate senescent cells. This one-two punch strategy approach presents a straightforward and potent intervention for both primary tumors and distant tumor.

Senescence-associated lineage-aberrant plasticity evokes T-cell-mediated tumor control

Cellular senescence is a stress-inducible state switch relevant in aging, tumorigenesis and cancer therapy. Beyond a lasting arrest, senescent cells are characterized by profound chromatin remodeling and transcriptional reprogramming. We show here myeloid-skewed aberrant lineage plasticity and its immunological ramifications in therapy-induced senescence (TIS) of primary human and murine B-cell lymphoma. We find myeloid transcription factor (TF) networks, specifically AP-1-, C/EBPβ- and PU.1-governed transcriptional programs, enriched in TIS but not in equally chemotherapy-exposed senescence-incapable cancer cells. Dependent on these master TF, TIS lymphoma cells adopt a lineage-promiscuous state with properties of monocytic-dendritic cell (DC) differentiation. TIS lymphoma cells are preferentially lysed by T-cells in vitro, and mice harboring DC-skewed Eμ-myc lymphoma experience significantly longer tumor-free survival. Consistently, superior long-term outcome is also achieved in diffuse large B-cell lymphoma patients with high expression of a TIS-related DC signature. In essence, these data demonstrate a therapeutically exploitable, prognostically favorable immunogenic role of senescence-dependent aberrant myeloid plasticity in B-cell lymphoma.

A Ruthenium(II) Complex Inhibits BRD4 for Synergistic Seno- and Chemo-Immunotherapy in Cisplatin-Resistant Tumor Cells

Drug resistance is a significant challenge for tumor therapy. Activating immunity is an effective method to combat drug-resistant tumors. Utilizing metallic chemotherapeutic agents to induce nonapoptotic programmed cell death is a practical approach to stimulate immunity. Besides, triggering tumor cell senescence, named senotherapy, is also an effective but often ignored method to induce immune responses. Despite some progress, reports on metallic immunotherapeutic stimuli are sparse and mainly delve into the level of organelle targeting, with vague drug-target mechanisms. Here, we report a Ru(II) complex (Ru2c) inhibits BRD4 with high affinity at a nanomolar constant. After encapsulation into biotin-DNA cage, Ru2c@biotin-DNA cage was demonstrated to kill drug-resistant cancer cells through a synergistic apoptosis-ferroptosis-senescence pathway, exhibiting 51-fold anticancer activity compared to the commercial inhibitor JQ-1. Ru2c effectively erased drug-resistant tumors and activated innate and acquired immunity in vivo. To the best of our knowledge, Ru2c is the first metal-based BRD4 inhibitor to achieve synergistic seno-immunotherapy and chemo-immunotherapy.

Age-dependent cytokine surge in blood precedes cancer diagnosis

Aging is associated with increased variability and dysregulation of the immune system. We performed a system-level analysis of serum cytokines in a longitudinal cohort of 133 healthy individuals over 9 y. We found that cancer incidence is a major contributor to increased cytokine abundance variability. Circulating cytokines increase up to 4 y before a cancer diagnosis in subjects with age over 80 y. We also analyzed cytokine expression in 10 types of early-stage cancers from The Cancer Genome Atlas. We found that a similar set of cytokines is upregulated in tumor tissues, specifically after the age of 80 y. Similarly, cellular senescence activity and CDKN1A/p21 expression increase with age in cancer tissues. Finally, we demonstrated that the cytokine levels in serum can be used to predict cancers among subjects age at 80+ y. Our results suggest that latent senescent cancers contribute to age-related chronic inflammation.

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.

The Regulation of Cellular Senescence in Cancer

Cellular senescence is a stable state of cell cycle arrest caused by telomere shortening or various stresses. After senescence, cells cease dividing and exhibit many age-related characteristics. Unlike the halted proliferation of senescence cells, cancer cells are considered to have unlimited growth potential. When cells display senescence-related features, such as telomere loss or stem cell failure, they can inhibit tumor development. Therefore, inducing cells to enter a senescence state can serve as a barrier to tumor cell development. However, many recent studies have found that sustained senescence of tumor cells or normal cells under certain circumstances can exert environment-dependent effects of tumor promotion and inhibition by producing various cytokines. In this review, we first introduce the causes and characteristics of induced cellular senescence, analyze the senescence process of immune cells and cancer cells, and then discuss the dual regulatory role of cell senescence on tumor growth and senescence-induced therapies targeting cancer cells. Finally, we discuss the role of senescence in tumor progression and treatment opportunities, and propose further studies on cellular senescence and cancer therapy.

Pharmacological rescue of mutant p53 triggers spontaneous tumor regression via immune responses

Tumor suppressor p53 is the most frequently mutated protein in cancer, possessing untapped immune-modulating capabilities in anticancer treatment. Here, we investigate the efficacy and underlying mechanisms of pharmacological reactivation of mutant p53 in treating spontaneous tumors in mice. In the p53 R279W (equivalent to the human hotspot R282W) mouse model developing spontaneous tumors, arsenic trioxide (ATO) treatment through drinking water significantly prolongs the survival of mice, dependent on p53-R279W reactivation. Transient regressions of spontaneous T-lymphomas are observed in 70% of the ATO-treated mice, accompanied by interferon (IFN) response. In allograft models, the tumor-suppressive effect of reactivated p53-R279W is detectably reduced in both immunodeficient Rag1-/- and CD8+ T cell-depleted mice. ATO also activates the IFN pathway in human cancer cells harboring various p53 mutations, as well as in primary samples derived from the p53-mutant patient treated with ATO. Together, p53 could serve as an alternative therapeutic target for the development of immunotherapies.

Systemic aging and aging-related diseases

Aging is a biological process along with systemic and multiple organ dysfunction. It is more and more recognized that aging is a systemic disease instead of a single-organ functional disorder. Systemic aging plays a profound role in multiple diseases including neurodegenerative diseases, cardiovascular diseases, and malignant diseases. Aged organs communicate with other organs and accelerate aging. Skeletal muscle, heart, bone marrow, skin, and liver communicate with each other through organ-organ crosstalk. The crosstalk can be mediated by metabolites including lipids, glucose, short-chain fatty acids (SCFA), inflammatory cytokines, and exosomes. Metabolic disorders including hyperglycemia, hyperinsulinemia, and hypercholesterolemia caused by chronic diseases accelerate hallmarks of aging. Systemic aging leads to the destruction of systemic hemostasis, causes the release of inflammatory cytokines, senescence-associated secretory phenotype (SASP), and the imbalance of microbiota composition. Released inflammatory factors further aggregate senescence, which promotes the aging of multiple solid organs. Targeting senescence or delaying aging is emerging as a critical health strategy for solving age-related diseases, especially in the old population. In the current review, we will delineate the mechanisms of organ crosstalk in systemic aging and age-related diseases to provide therapeutic targets for delaying aging.

Targeting T-cell Aging to Remodel the Aging Immune System and Revitalize Geriatric Immunotherapy

The aging immune system presents profound challenges, notably through the decline of T cell function, which is critical for effective immune responses. As age-related changes lead to diminished T cell diversity and heighten immunosuppressive environments, older individuals face increased susceptibility to infections, autoimmune diseases, and reduced efficacy of immunotherapies. This review investigates the intricate mechanisms by which T cell aging drives immunosenescence, including immune suppression, immune evasion, reduced antigen reactivity, and the overexpression of immune checkpoint molecules. By delving into innovative therapeutic strategies aimed at rejuvenating T cell populations and modifying the immunological landscape, we highlight the potential for enhancing immune resilience in the elderly. Ultimately, our goal is to outline actionable pathways for restoring immune function, thereby improving health outcomes for aging individuals facing immunological decline.

Exosomal dynamics: Bridging the gap between cellular senescence and cancer therapy

Cancer remains one of the most devastating diseases, severely affecting public health and contributing to economic instability. Researchers worldwide are dedicated to developing effective therapeutics to target cancer cells. One promising strategy involves inducing cellular senescence, a complex state in which cells exit the cell cycle. Senescence has profound effects on both physiological and pathological processes, influencing cellular systems through secreted factors that affect surrounding and distant cells. Among these factors are exosomes, small extracellular vesicles that play crucial roles in cellular communication, development, and defense, and can contribute to pathological conditions. Recently, there has been increasing interest in engineering exosomes as precise drug delivery vehicles, capable of targeting specific cells or intracellular components. Studies have emphasized the significant role of exosomes from senescent cells in cancer progression and therapy. Notably, chemotherapeutic agents can alter the tumor microenvironment, induce senescence, and trigger immune responses through exosome-mediated cargo transfer. This review explores the intricate relationship between cellular senescence, exosomes, and cancer, examining how different therapeutics can eliminate cancer cells or promote drug resistance. It also investigates the molecular mechanisms and signaling pathways driving these processes, highlighting current challenges and proposing future perspectives to uncover new therapeutic strategies for cancer treatment.

Redox regulation: mechanisms, biology and therapeutic targets in diseases

Redox signaling acts as a critical mediator in the dynamic interactions between organisms and their external environment, profoundly influencing both the onset and progression of various diseases. Under physiological conditions, oxidative free radicals generated by the mitochondrial oxidative respiratory chain, endoplasmic reticulum, and NADPH oxidases can be effectively neutralized by NRF2-mediated antioxidant responses. These responses elevate the synthesis of superoxide dismutase (SOD), catalase, as well as key molecules like nicotinamide adenine dinucleotide phosphate (NADPH) and glutathione (GSH), thereby maintaining cellular redox homeostasis. Disruption of this finely tuned equilibrium is closely linked to the pathogenesis of a wide range of diseases. Recent advances have broadened our understanding of the molecular mechanisms underpinning this dysregulation, highlighting the pivotal roles of genomic instability, epigenetic modifications, protein degradation, and metabolic reprogramming. These findings provide a foundation for exploring redox regulation as a mechanistic basis for improving therapeutic strategies. While antioxidant-based therapies have shown early promise in conditions where oxidative stress plays a primary pathological role, their efficacy in diseases characterized by complex, multifactorial etiologies remains controversial. A deeper, context-specific understanding of redox signaling, particularly the roles of redox-sensitive proteins, is critical for designing targeted therapies aimed at re-establishing redox balance. Emerging small molecule inhibitors that target specific cysteine residues in redox-sensitive proteins have demonstrated promising preclinical outcomes, setting the stage for forthcoming clinical trials. In this review, we summarize our current understanding of the intricate relationship between oxidative stress and disease pathogenesis and also discuss how these insights can be leveraged to optimize therapeutic strategies in clinical practice.

Senescent Cell-Derived Extracellular Vesicles Inhibit Cancer Recurrence by Coordinating Immune Surveillance

Senescence is a nonproliferative survival state that cancer cells can enter to escape therapy. In addition to soluble factors, senescence cells secrete extracellular vesicles (EV), which are important mediators of intercellular communication. To explore the role of senescent cell (SC)-derived EVs (senEV) in inflammatory responses to senescence, we developed an engraftment-based senescence model in wild-type mice and genetically blocked senEV release in vivo, without significantly affecting soluble mediators. SenEVs were both necessary and sufficient to trigger immune-mediated clearance of SCs, thereby suppressing tumor growth. In the absence of senEVs, the recruitment of MHC-II+ antigen-presenting cells (APC) to the senescence microenvironment was markedly impaired. Blocking senEV release redirected the primary target of SC signaling from APCs to neutrophils. Comprehensive transcriptional and proteomic analyses identified six ligands specific to senEVs, highlighting their role in promoting APC-T cell adhesion and synapse formation. APCs activated CCR2+CD4+ TH17 cells, which seemed to inhibit B-cell activation, and CD4+ T cells were essential for preventing tumor recurrence. These findings suggest that senEVs complement the activity of secreted inflammatory mediators by recruiting and activating distinct immune cell subsets, thereby enhancing the efficient clearance of SCs. These conclusions may have implications not only for tumor recurrence but also for understanding senescence during de novo carcinogenesis. Consequently, this work could inform the development of early detection strategies for cancer based on the biology of cellular senescence. Significance: Chemotherapy-treated senescent tumor cells release extracellular vesicles that trigger an immune response and suppress tumor recurrence. See related commentary by Almeida and Melo, p. 833.

Immune surveillance of senescence: potential application to age-related diseases

Several lines of evidence suggest that the age-dependent accumulation of senescent cells leads to chronic tissue microinflammation, which in turn contributes to age-related pathologies. In general, senescent cells can be eliminated by the host's innate and adaptive immune surveillance system, including macrophages, NK cells, and T cells. Impaired immune surveillance leads to the accumulation of senescent cells and accelerates the aging process. Recently, senescent cells, like cancer cells, have been shown to express certain types of immune checkpoint proteins as well as non-classical immune-tolerant MHC variants, leading to immune escape from surveillance systems. Thus, immune checkpoint blockade (ICB) may be a promising strategy to enhance immune surveillance of senescence, leading to the amelioration of some age-related diseases and tissue dysfunction.

From bench to bedside: The critical need for standardized senescence detection

Cellular senescence, identified as a state of permanent cell cycle arrest, has become central to understanding aging and disease. Initially seen as a cellular aging mechanism, it is now recognized for its roles in development, tissu repair and tumour suppression. However, the accumulation of senescent cells with age contributes to chronic diseases such as diabetes, atherosclerosis and neurodegeneration. Recent efforts have focused on "senotherapeutics", including senolytics, which aim to eliminate senescent cells to mitigate age-related decline. Despite significant advances, senescence research faces critical challenges because of inconsistent detection methods. Common markers, such as p16INK4a and senescence-associated β-galactosidase, vary across tissues and contexts, complicating cross-study comparisons and clinical applications. A standardized multifaceted approach to senescence detection is essential, and should incorporate complementary methods, clear thresholds for senescence classification and considerations for cell type-specific variations. Such standardization would enhance reproducibility, streamline research and facilitate clinical translation, advancing therapeutic applications in aging and disease management.

Bone morphogenetic protein (BMP) signaling determines neuroblastoma cell fate and sensitivity to retinoic acid

Retinoic acid (RA) is a standard-of-care neuroblastoma drug thought to be effective by inducing differentiation. Curiously, RA has little effect on primary human tumors during upfront treatment but can eliminate neuroblastoma cells from the bone marrow during post-chemo maintenance therapy-a discrepancy that has never been explained. To investigate this, we treat a large cohort of neuroblastoma cell lines with RA and observe that the most RA-sensitive cells predominantly undergo apoptosis or senescence, rather than differentiation. We conduct genome-wide CRISPR knockout screens under RA treatment, which identify bone morphogenic protein (BMP) signaling as controlling the apoptosis/senescence vs differentiation cell fate decision and determining RA's overall potency. We then discover that BMP signaling activity is markedly higher in neuroblastoma patient samples at bone marrow metastatic sites, providing a plausible explanation for RA's ability to clear neuroblastoma cells specifically from the bone marrow, by seemingly mimicking interactions between BMP and RA during normal development.

Extracellular vesicles-based vaccines: Emerging immunotherapies against cancer

Cancer vaccines are promising therapeutic approaches to enhance specific T-cell immunity against most solid tumors. By stimulating anti-tumor immunity, clearing minimal residual disease, and minimizing adverse effects, these vaccines target tumor cells and are effective when combined with immune checkpoint blockade or other immunotherapies. However, the development of tumor cell-based vaccines faces quality issues due to poor immunogenicity, tumor heterogeneity, a suppressive tumor immune microenvironment, and ineffective delivery methods. In contrast, extracellular vesicles (EVs), naturally released by cells, are considered the ideal drug carriers and vaccine platforms. EVs offer highly organ-specific targeting, induce broader and more effective immune responses, and demonstrate superior tissue delivery ability. The development of EV vaccines is crucial for advancing cancer immunotherapy. Compared to cell-based vaccines, EV vaccines produced under Good Manufacturing Practices (GMP) offer advantages such as high safety, ease of preservation and transport, and a wide range of sources. This review summarizes the latest research findings on EV vaccine and potential applications in this field. It also highlights novel neoantigens for the development of EV vaccines against cancer.

The p53-miR17 family-Rankl axis bridges liver-bone communication

Our study elucidates the crucial role of the liver in bone homeostasis through the p53-miR17 family (miR17-miR20/miR20-miR106/miR93-miR106)-Rankl axis. We demonstrate the enhanced hepatocyte Rankl expression in inflammaging conditions, such as aging, ovariectomized (OVX) mice, and elderly humans. Mice with hepatocyte-specific Rankl deletion exhibit significant resistance to bone mass loss associated with aging, lipopolysaccharide (LPS)-induced inflammation, or estrogen deficiency, compared with controls. Our study highlights hepatocytes as the primary source of Rankl in the liver and serum under these conditions. We identify the p53-miR17 family axis as a crucial regulator for hepatocyte Rankl expression, with p53 inhibiting the miR17 family transcription. Through bioinformatics analysis and in vitro validation, we identify Rankl mRNA as a direct target of the miR17 family. Targeting this axis via CasRx-mediated mRNA editing or miRNA interference significantly attenuates bone mass loss in mice. Our investigation underscores the pivotal significance and therapeutic potential of modulating the p53-miR17 family-Rankl axis in the treatment of inflammaging-associated osteoporosis.

Immune therapeutic strategies for the senescent tumor microenvironment

Senescent cells can either to promote immunosuppressive tumor microenvironment or facilitate immune surveillance. Despite the revolutionary impact of cancer immunotherapy, durable responses in solid tumors, particularly in advanced stages, remain limited. Recent studies have shed light on the influence of senescent status within the tumor microenvironment (TME) on therapy resistance and major efforts are needed to overcome these challenges. This review summarizes recent advancements in targeting cellular senescence, with a particular focus on immunomodulatory approaches on the hallmarks of cellular senescence.

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.

Berberine Derivative B68 Promotes Tumor Immune Clearance by Dual-Targeting BMI1 for Senescence Induction and CSN5 for PD-L1 Degradation

Promoting tumor cell senescence arrests the cell cycle of tumor cells and activates the immune system to eliminate these senescent cells, thereby suppressing tumor growth. Nevertheless, PD-L1 positive senescent tumor cells resist immune clearance and possess the ability to secret various cytokines and inflammatory factors that stimulate the growth of tumor cells. Consequently, drugs capable of both triggering senescence in tumor cells and concurrently diminishing the expression of PD-L1 to counteract immune evasion are urgently needed. Here, a berberine derivative B68 is developed, which specifically induces tumor cell senescence by targeting BMI1. B68 also involves the degradation of PD-L1 by targeting CSN5, thereby disrupting the immunosuppressive PD-1/PD-L1 interaction and enabling rapid clearance of senescent tumor cells. This approach simultaneously inhibits tumor progression and activates T cell immunity, as evidenced by the robust antitumor response following B68-induced immunization of senescent cancer cells. Moreover, the synergistic effect of B68 with anti-CTLA4 therapy further enhances antitumor immunity, and its ability to induce senescence in cancer cells triggers a strong protective response by dendritic and CD8+ T cells. These findings provide a scientific basis for developing a new tumor treatment strategy based on senescence induction and lay the foundation for further preclinical research.

Genetically engineered CD276-anchoring biomimetic nanovesicles target senescent escaped tumor cells to overcome chemoresistant and immunosuppressive breast cancer

Chemotherapy-induced cellular senescence leads to an increased proportion of cancer stem cells (CSCs) in breast cancer (BC), contributing to recurrence and metastasis, while effective means to clear them are currently lacking. Herein, we aim to develop new approaches for selectively killing senescent-escape CSCs. High CD276 (95.60%) expression in multidrug-resistant BC cells, facilitates immune evasion by low-immunogenic senescent escape CSCs. CALD1, upregulated in ADR-resistant BC, promoting senescent-escape of CSCs with an anti-apoptosis state and upregulating CD276, PD-L1 to promote chemoresistance and immune escape. We have developed a controlled-released thermosensitive hydrogel containing pH- responsive anti-CD276 scFV engineered biomimetic nanovesicles to overcome BC in primary, recurrent, metastatic and abscopal humanized mice models. Nanovesicles coated anti-CD276 scFV selectively fuses with cell membrane of senescent-escape CSCs, then sequentially delivers siCALD1 and ADR due to pH-responsive MnP shell. siCALD1 together with ADR effectively induce apoptosis of CSCs, decrease expression of CD276 and PD-L1, and upregulate MHC I combined with Mn2+ to overcome chemoresistance and promote CD8+T cells infiltration. This combined therapeutic approach reveals insights into immune surveillance evasion by senescent-escape CSCs, offering a promising strategy to immunotherapy effectiveness in cancer therapy.

A Distinguished Roadmap of Fibroblast Senescence in Predicting Immunotherapy Response and Prognosis Across Human Cancers

The resistance of tumors to immune checkpoint inhibitors (ICI) may be intricately linked to cellular senescence, although definitive clinical validation remains elusive. In this study, comprehensive pan-cancer scRNA-seq analyses identify fibroblasts as exhibiting the most pronounced levels of cellular senescence among tumor-associated cell populations. To elucidate this phenomenon, a fibroblast senescence-associated transcriptomic signature (FSS), which correlated strongly with protumorigenic signaling pathways and immune dysregulation that fosters tumor progression, is developed. Leveraging the FSS, the machine learning (ML) framework demonstrates exceptional accuracy in predicting ICI response and survival outcomes, achieving superior area under curve (AUC) values across validation, testing, and in-house cohorts. Strikingly, FSS consistently outperforms established signatures in predictive robustness across diverse cancer subtypes. From an integrative analysis of 17 CRISPR/Cas9 libraries, CDC6 emerges as a pivotal biomarker for pan-cancer ICI response and prognostic stratification. Mechanistically, experimental evidence reveals that CDC6 in tumor cells orchestrates fibroblast senescence via TGF-β1 secretion and oxidative stress, subsequently reprogramming the tumor microenvironment and modulating ICI response. These findings underscore the translational potential of targeting fibroblast senescence as a novel therapeutic strategy to mitigate immune resistance and enhance antitumor efficacy.

SMARCA4 regulates the NK-mediated killing of senescent cells

Induction of senescence by chemotherapeutic agents arrests cancer cells and activates immune surveillance responses to contribute to therapy outcomes. In this investigation, we searched for ways to enhance the NK-mediated elimination of senescent cells. We used a staggered screen approach, first identifying siRNAs potentiating the secretion of immunomodulatory cytokines to later test for their ability to enhance NK-mediated killing of senescent cells. We identified that genetic or pharmacological inhibition of SMARCA4 enhanced senescent cell elimination by NK cells. SMARCA4 expression is elevated during senescence and its inhibition derepresses repetitive elements, inducing the SASP via activation of cGAS/STING and MAVS/MDA5 pathways. Moreover, a PROTAC targeting SMARCA4 synergized with cisplatin to increase the infiltration of CD8 T cells and mature, activated NK cells in an immunocompetent model of ovarian cancer. Our results indicate that SMARCA4 inhibitors enhance NK-mediated surveillance of senescent cells and may represent senotherapeutic interventions for ovarian cancer.

Broad repression of DNA repair genes in senescent cells identified by integration of transcriptomic data

Cellular senescence plays a significant role in tissue aging. Senescent cells, which resist apoptosis while remaining metabolically active, generate endogenous DNA-damaging agents, primarily reactive oxygen species. Efficient DNA repair is therefore crucial in these cells, especially when they undergo senescence escape, resuming DNA replication and cellular proliferation. To investigate whether senescent cell transcriptomes reflect adequate DNA repair capacity, we conducted a comprehensive meta-analysis of 60 transcriptomic datasets comparing senescent to proliferating cells. Our analysis revealed a striking downregulation of genes encoding essential components across DNA repair pathways in senescent cells. This includes pathways active in different cell cycle phases such as nucleotide excision repair, base excision repair, nonhomologous end joining and homologous recombination repair of double-strand breaks, mismatch repair and interstrand crosslink repair. The downregulation observed suggests a significant accumulation of DNA lesions. Experimental monitoring of DNA repair readouts in cells that underwent radiation-induced senescence supported this conclusion. This phenomenon was consistent across various senescence triggers and was also observed in primary cell lines from aging individuals. These findings highlight the potential of senescent cells as 'ticking bombs' in aging-related diseases and tumors recurring following therapy-induced senescence.

Therapy-induced senescent cancer cells contribute to cancer progression by promoting ribophorin 1-dependent PD-L1 upregulation

Conventional chemotherapy- and radiotherapy-induced cancer senescence, which is characterized by poor proliferation, drug resistance, and senescence-associated secretory phenotype, has gained attention as contributing to cancer relapse and the development of an immunosuppressive tumor microenvironment. However, the association between cancer senescence and anti-tumor immunity is not fully understood. Here, we demonstrate that senescent cancer cells increase the level of PD-L1 by promoting its transcription and glycosylation. We identify ribophorin 1 as a key regulator of PD-L1 glycosylation during cancer senescence. Ribophorin 1 depletion reduces this elevated level of PD-L1 through the ER-lysosome-associated degradation pathway, thereby increasing the susceptibility of senescent cancer cells to T-cell-mediated killing. Consistently, ribophorin 1 depletion suppresses tumor growth by decreasing PD-L1 levels and boosting cytotoxic T lymphocyte activity in male mice. Moreover, ribophorin 1-targeted or anti-PD-1 therapy reduces the number of senescent cancer cells in irradiated tumors and suppresses cancer recurrence through the activation of cytotoxic T lymphocytes. These results provide crucial insights into how senescent cancer cells can escape T-cell immunity following cancer treatment and thereby contribute to cancer recurrence. Our findings also highlight the therapeutic promise of targeting senescent cancer cells for cancer treatment.

H4K20me3-Mediated Repression of Inflammatory Genes Is a Characteristic and Targetable Vulnerability of Persister Cancer Cells

Anticancer therapies can induce cellular senescence or drug-tolerant persistence, two types of proliferative arrest that differ in their stability. While senescence is highly stable, persister cells efficiently resume proliferation upon therapy termination, resulting in tumor relapse. Here, we used an ATP-competitive mTOR inhibitor to induce and characterize persistence in human cancer cells of various origins. Using this model and previously described models of senescence, we compared the same cancer cell lines under the two types of proliferative arrest. Persister and senescent cancer cells shared an expanded lysosomal compartment and hypersensitivity to BCL-XL inhibition. However, persister cells lacked other features of senescence, such as loss of lamin B1, senescence-associated β-galactosidase activity, upregulation of MHC-I, and an inflammatory and secretory phenotype (senescence-associated secretory phenotype or SASP). A genome-wide CRISPR/Cas9 screening for genes required for the survival of persister cells revealed that they are hypersensitive to the inhibition of one-carbon (1C) metabolism, which was validated by the pharmacologic inhibition of serine hydroxymethyltransferase, a key enzyme that feeds methyl groups from serine into 1C metabolism. Investigation into the relationship between 1C metabolism and the epigenetic regulation of transcription uncovered the presence of the repressive heterochromatic mark H4K20me3 at the promoters of SASP and IFN response genes in persister cells, whereas it was absent in senescent cells. Moreover, persister cells overexpressed the H4K20 methyltransferases KMT5B/C, and their downregulation unleashed inflammatory programs and compromised the survival of persister cells. In summary, this study identifies distinctive features and actionable vulnerabilities of persister cancer cells and provides mechanistic insight into their low inflammatory activity. Significance: Cell persistence and senescence are distinct states of proliferative arrest induced by cancer therapy, with persister cells being characterized by the silencing of inflammatory genes through the heterochromatic mark H4K20me3. See related commentary by Schmitt, p. 7.

Decoding T cell senescence in cancer: Is revisiting required?

Senescence is an inherent cellular mechanism triggered as a response to stressful insults. It associates with several aspects of cancer progression and therapy. Senescent cells constitute a highly heterogeneous cellular population and their identification can be very challenging. In fact, the term "senescence" has been often misused. This is also true in the case of immune cells. While several studies indicate the presence of senescent-like features (mainly in T cells), senescent immune cells are poorly described. Under this prism, we herein review the current literature on what has been characterized as T cell senescence and provide insights on how to accurately discriminate senescent cells against exhausted or anergic ones. We also summarize the major metabolic and epigenetic modifications associated with T cell senescence and underline the role of senescent T cells in the tumor microenvironment (TME). Moreover, we discuss how these cells associate with standard clinical therapeutic interventions and how they impact their efficacy. Finally, we underline the importance of precise identification and thorough characterization of "truly" senescent T cells in order to design successful therapeutic manipulations that would delay cancer incidence and maximize efficacy of immunotherapy.

Cellular senescence as a source of chronic microinflammation that promotes the aging process

Why and how do we age? This physiological phenomenon that we all experience remains a great mystery, largely unexplained even in this age of scientific and technological progress. Aging is a significant risk factor for numerous diseases, including cancer. However, underlying mechanisms responsible for this association remain to be elucidated. Recent findings have elucidated the significance of the accumulation of senescent cells and other inflammatory cells in organs and tissues with age, and their deleterious effects, such as the induction of inflammation in the microenvironment, as underlying factors contributing to organ dysfunction and disease development. Cellular senescence is a cellular phenomenon characterized by a permanent cessation of cell proliferation and secretion of several proinflammatory cytokines (senescence associated secretory phenotypes). Notably, the elimination of senescent cells from aging individuals has been demonstrated to alleviate age-related organ and tissue dysfunction, as well as various geriatric diseases. This review summarizes the molecular mechanisms by which senescent cells are induced and contribute to age-related diseases, as well as the technologies that ameliorate them.

Decoding the role of SLC25A5 in osteosarcoma drug resistance and CD8+ T cell exhaustion: The therapeutic potential of phyllanthin

Osteosarcoma is an aggressive malignant bone tumor with an obscure etiology, as well as high prevalence and poor prognosis in children and adolescents. We aimed to investigate the pathogenesis of osteosarcoma through a comprehensive analysis of the tumor immune microenvironment (TIME) using multiple single-cell RNA sequencing datasets. SLC25A5, a gene implicated in cellular aging, significantly influenced osteosarcoma development by altering the TIME and promoting CD8+ T cell exhaustion, which contributed to reduced chemosensitivity. Experimental validation demonstrated that SLC25A5 enhanced the proliferative, migratory, invasive, and osteolytic properties of drug-resistant osteosarcoma cells while reducing apoptosis, intensifying cisplatin resistance. Phyllanthin inhibited the malignant phenotype of cisplatin-resistant osteosarcoma cells and enhanced their sensitivity to cisplatin by suppressing SLC25A5 expression. This study highlights a novel pathogenic role of SLC25A5 in osteosarcoma and presents Phyllanthin as a promising therapeutic agent. Our study offers a pioneering exploration of the single-cell spatiotemporal evolution of osteosarcoma and identifies SLC25A5 as a critical factor in drug resistance and immune evasion. By integrating advanced single-cell technologies and functional assays, we provided novel insights into the molecular mechanisms underlying osteosarcoma progression and treatment resistance, facilitating innovative therapeutic strategies.

The crosstalk between senescence, tumor, and immunity: molecular mechanism and therapeutic opportunities

Cellular senescence is characterized by a stable cell cycle arrest and a hypersecretory, proinflammatory phenotype in response to various stress stimuli. Traditionally, this state has been viewed as a tumor-suppressing mechanism that prevents the proliferation of damaged cells while activating the immune response for their clearance. However, senescence is increasingly recognized as a contributing factor to tumor progression. This dual role necessitates a careful evaluation of the beneficial and detrimental aspects of senescence within the tumor microenvironment (TME). Specifically, senescent cells display a unique senescence-associated secretory phenotype that releases a diverse array of soluble factors affecting the TME. Furthermore, the impact of senescence on tumor-immune interaction is complex and often underappreciated. Senescent immune cells create an immunosuppressive TME favoring tumor progression. In contrast, senescent tumor cells could promote a transition from immune evasion to clearance. Given these intricate dynamics, therapies targeting senescence hold promise for advancing antitumor strategies. This review aims to summarize the dual effects of senescence on tumor progression, explore its influence on tumor-immune interactions, and discuss potential therapeutic strategies, alongside challenges and future directions. Understanding how senescence regulates antitumor immunity, along with new therapeutic interventions, is essential for managing tumor cell senescence and remodeling the immune microenvironment.

Senescence as a therapeutic target in cancer and age-related diseases

Cellular senescence is a stress response that restrains the growth of aged, damaged or abnormal cells. Thus, senescence has a crucial role in development, tissue maintenance and cancer prevention. However, lingering senescent cells fuel chronic inflammation through the acquisition of a senescence-associated secretory phenotype (SASP), which contributes to cancer and age-related tissue dysfunction. Recent progress in understanding senescence has spurred interest in the development of approaches to target senescent cells, known as senotherapies. In this Review, we evaluate the status of various types of senotherapies, including senolytics that eliminate senescent cells, senomorphics that suppress the SASP, interventions that mitigate senescence and strategies that harness the immune system to clear senescent cells. We also summarize how these approaches can be combined with cancer therapies, and we discuss the challenges and opportunities in moving senotherapies into clinical practice. Such therapies have the potential to address root causes of age-related diseases and thus open new avenues for preventive therapies and treating multimorbidities.

Combined Autophagy Inhibition and Dendritic Cell Recruitment Induces Antitumor Immunity and Enhances Immune Checkpoint Blockade Sensitivity in Pancreatic Cancer

The effect of immune checkpoint inhibitors is extremely limited in patients with pancreatic ductal adenocarcinoma (PDAC) due to the suppressive tumor immune microenvironment. Autophagy, which has been shown to play a role in antitumor immunity, has been proposed as a therapeutic target for PDAC. In this study, single-cell RNA sequencing of autophagy-deficient murine PDAC tumors revealed that autophagy inhibition in cancer cells induced dendritic cell (DC) activation. Analysis of human PDAC tumors substantiated a negative correlation between autophagy and DC activation signatures. Mechanistically, autophagy inhibition increased the intracellular accumulation of tumor antigens, which could activate DCs. Administration of chloroquine, an autophagy inhibitor, in combination with Flt3 ligand-induced DC infiltration inhibited tumor growth and increased tumor-infiltrating T lymphocytes. However, autophagy inhibition in cancer cells also induced CD8+ T-cell exhaustion with high expression of immune checkpoint LAG3. A triple-therapy comprising chloroquine, Flt3 ligand, and an anti-LAG3 antibody markedly reduced tumor growth in orthotopic syngeneic PDAC mouse models. Thus, targeting autophagy in cancer cells and activating DCs sensitize PDAC tumors to immune checkpoint inhibitor therapy, warranting further development of this treatment approach to overcome immunosuppression in pancreatic cancer. Significance: Inhibiting autophagy in pancreatic cancer cells enhances intracellular accumulation of tumor antigens to induce dendritic cell activation and synergizes with immunotherapy to markedly inhibit the growth of pancreatic ductal adenocarcinoma.

Senolytic Vaccines from the Central and Peripheral Tolerance Perspective

Preventive medicine has proven its long-term effectiveness and economic feasibility. Over the last century, vaccination has saved more lives than any other medical technology. At present, preventative measures against most infectious diseases are successfully used worldwide; in addition, vaccination platforms against oncological and even autoimmune diseases are being actively developed. At the same time, the development of medicine led to an increase in both life expectancy and the proportion of age-associated diseases, which pose a heavy socio-economic burden. In this context, the development of vaccine-based approaches for the prevention or treatment of age-related diseases opens up broad prospects for extending the period of active longevity and has high economic potential. It is well known that the development of age-related diseases is associated with the accumulation of senescent cells in various organs and tissues. It has been demonstrated that the elimination of such cells leads to the restoration of functions, rejuvenation, and extension of the lives of experimental animals. However, the development of vaccines against senescent cells is complicated by their antigenic heterogeneity and the lack of a unique marker. In addition, senescent cells are the body's own cells, which may be the reason for their low immunogenicity. This mini-review discusses the mechanisms of central and peripheral tolerance that may influence the formation of an anti-senescent immune response and be responsible for the accumulation of senescent cells with age.

Genetic origins, regulators, and biomarkers of cellular senescence

This review comprehensively examines the molecular biology and genetic origins of cellular senescence. We focus on various cellular stressors and pathways leading to senescence, including recent advances in the understanding of the genetic influences driving senescence, such as telomere attrition, chemotherapy-induced DNA damage, pathogens, oncogene activation, and cellular and metabolic stress. This review also highlights the complex interplay of various signaling and metabolic pathways involved in cellular senescence and provides insights into potential therapeutic targets for aging-related diseases. Furthermore, this review outlines future research directions to deepen our understanding of senescence biology and develop effective interventions targeting senescent cells (SnCs).

SenNet recommendations for detecting senescent cells in different tissues

Once considered a tissue culture-specific phenomenon, cellular senescence has now been linked to various biological processes with both beneficial and detrimental roles in humans, rodents and other species. Much of our understanding of senescent cell biology still originates from tissue culture studies, where each cell in the culture is driven to an irreversible cell cycle arrest. By contrast, in tissues, these cells are relatively rare and difficult to characterize, and it is now established that fully differentiated, postmitotic cells can also acquire a senescence phenotype. The SenNet Biomarkers Working Group was formed to provide recommendations for the use of cellular senescence markers to identify and characterize senescent cells in tissues. Here, we provide recommendations for detecting senescent cells in different tissues based on a comprehensive analysis of existing literature reporting senescence markers in 14 tissues in mice and humans. We discuss some of the recent advances in detecting and characterizing cellular senescence, including molecular senescence signatures and morphological features, and the use of circulating markers. We aim for this work to be a valuable resource for both seasoned investigators in senescence-related studies and newcomers to the field.

The danger theory of immunity revisited

The danger theory of immunity, introduced by Polly Matzinger in 1994, posits that tissue stress, damage or infection has a decisive role in determining immune responses. Since then, a growing body of evidence has supported the idea that the capacity to elicit cognate immune responses (immunogenicity) relies on the combination of antigenicity (the ability to be recognized by T cell receptors or antibodies) and adjuvanticity (additional signals arising owing to tissue damage). Here, we discuss the molecular foundations of the danger theory while focusing on immunologically relevant damage-associated molecular patterns, microorganism-associated molecular patterns, and neuroendocrine stress-associated immunomodulatory molecules, as well as on their receptors. We critically evaluate patient-relevant evidence, examining how cancer cells and pathogenic viruses suppress damage-associated molecular patterns to evade immune recognition, how intestinal dysbiosis can reduce immunostimulatory microorganism-associated molecular patterns and compromise immune responses, and which hereditary immune defects support the validity of the danger theory. Furthermore, we incorporate the danger hypothesis into a close-to-fail-safe hierarchy of immunological tolerance mechanisms that also involve the clonal deletion and inactivation of immune cells.

Mechanisms and cross-talk of regulated cell death and their epigenetic modifications in tumor progression

Cell death is a fundamental part of life for metazoans. To maintain the balance between cell proliferation and metabolism of human bodies, a certain number of cells need to be removed regularly. Hence, the mechanisms of cell death have been preserved during the evolution of multicellular organisms. Tumorigenesis is closely related with exceptional inhibition of cell death. Mutations or defects in cell death-related genes block the elimination of abnormal cells and enhance the resistance of malignant cells to chemotherapy. Therefore, the investigation of cell death mechanisms enables the development of drugs that directly induce tumor cell death. In the guidelines updated by the Cell Death Nomenclature Committee (NCCD) in 2018, cell death was classified into 12 types according to morphological, biochemical and functional classification, including intrinsic apoptosis, extrinsic apoptosis, mitochondrial permeability transition (MPT)-driven necrosis, necroptosis, ferroptosis, pyroptosis, PARP-1 parthanatos, entotic cell death, NETotic cell death, lysosome-dependent cell death, autophagy-dependent cell death, immunogenic cell death, cellular senescence and mitotic catastrophe. The mechanistic relationships between epigenetic controls and cell death in cancer progression were previously unclear. In this review, we will summarize the mechanisms of cell death pathways and corresponding epigenetic regulations. Also, we will explore the extensive interactions between these pathways and discuss the mechanisms of cell death in epigenetics which bring benefits to tumor therapy.

Nuclear PD-L1 compartmentalization suppresses tumorigenesis and overcomes immunocheckpoint therapy resistance in mice via histone macroH2A1

Canonically PD-L1 functions as the inhibitory immune checkpoint on cell surface. Recent studies have observed PD-L1 expression in the nucleus of cancer cells. But the biological function of nuclear PD-L1 (nPD-L1) in tumor growth and antitumor immunity is unclear. Here we enforced nPD-L1 expression and established stable cells. nPD-L1 suppressed tumorigenesis and aggressiveness in vitro and in vivo. Compared with PD-L1 deletion, nPD-L1 expression repressed tumor growth and improved survival more markedly in immunocompetent mice. Phosphorylated AMPKα (p-AMPKα) facilitated nuclear PD-L1 compartmentalization and then cooperated with it to directly phosphorylate S146 of histone variant macroH2A1 (mH2A1) to epigenetically activate expression of genes of cellular senescence, JAK/STAT, and Hippo signaling pathways. Lipoic acid (LA) that induced nuclear PD-L1 translocation suppressed tumorigenesis and boosted antitumor immunity. Importantly, LA treatment synergized with PD-1 antibody and overcame immune checkpoint blockade (ICB) resistance, which likely resulted from nPD-L1-increased MHC-I expression and sensitivity of tumor cells to interferon-γ. These findings offer a conceptual advance for PD-L1 function and suggest LA as a promising therapeutic option for overcoming ICB resistance.