Tumor cellular senescence, characterized by reversible cell cycle arrest following anti-cancer therapies, presents a complex paradigm in oncology. Given that senescent tumor cells may promote angiogenesis, tumorigenesis, and metastasis, selective killing senescent cells (SCs)-a strategy termed senotherapy-has emerged as a promising approach to improve cancer treatment. However, the clinical implementation of senotherapy faces significant hurdles, including lack of precise methods for SCs identification and the potential for adverse effects associated with highly cytotoxic senolytic agents. In this account, we elucidate recent advancement in developing novel approaches for the detection and selective elimination of SCs, encompassing prodrugs, nanoparticles, and other cutting-edge drug delivery systems such as PROTAC technology and CAR T cell therapy. Furthermore, we explore the paradoxical nature of SCs, which can induce growth arrest in adjacent neoplastic cells and recruit immunomodulatory cells that contribute to tumor suppression. Therefore, we utilize SCs membrane as vehicles to elicit antitumor immunity and potentially augment existing anti-cancer therapies. Finally, the opportunities and challenges are put forward to facilitate the development and clinical transformation of SCs detection, elimination or utilization.

Age-related diseases imposed heavy burdens to the healthcare systems globally, while cell senescence served as one fundamental molecular/cellular basis for these diseases. How to tackle the senescence-relevant problems is a hotspot for biomedical research. In this review article, the hallmarks and molecular pathways of cell senescence were firstly discussed, followed by the introduction of the current anti-senescence strategies, including senolytics and senomorphics. With suitable physical or chemical properties, multiple types of nanomaterials were used successfully in senescence therapeutics, as well as senescence detection. Based on the accumulating knowledges for senescence, the rules of how to use these nanoplatforms more efficiently against senescence were also summarized, including but not limited to surface modification, material-cargo interactions, factor responsiveness etc. The comparison of these "senescence-selective" nanoplatforms to other treatment options (prodrugs, ADCs, PROTACs, CART etc.) was also given. Learning from the past, nanotechnology can add more choice for treating age-related diseases, and provide more (diagnostic) information to further our understanding of senescence process.

In human beings heterogenous, pervasive and lethal malignancies of different parts of the gastrointestinal (GI) tract viz., tumours of the oesophagus, stomach, small intestine, colon, and rectum, represent gastrointestinal malignancies. Primary treatment modality for gastric cancer includes chemotherapy, surgical interventions, radiotherapy, monoclonal antibodies and inhibitors of angiogenesis. However, there is a need to improve upon the existing treatment modality due to associated adverse events and the development of resistance towards treatment. Additionally, age has been found to contribute to increasing the incidence of tumours due to immunosenescence-associated immunosuppression. Immunosenescence is the natural process of ageing, wherein immune cells as well as organs begin to deteriorate resulting in a dysfunctional or malfunctioning immune system. Accretion of senescent cells in immunosenescence results in the creation of a persistent inflammatory environment or inflammaging, marked with elevated expression of pro-inflammatory and immunosuppressive cytokines and chemokines. Perturbation in the T-cell pools and persistent stimulation by the antigens facilitate premature senility of the immune cells, and senile immune cells exacerbate inflammaging conditions and the inefficiency of the immune system to identify the tumour antigen. Collectively, these conditions contribute positively towards tumour generation, growth and eventually proliferation. Thus, activating the immune cells to distinguish the tumour cells from normal cells and invade them seems to be a logical strategy for the treatment of cancer. Consequently, various approaches to immunotherapy, viz., programmed death ligand-1 (PD-1) inhibitors, Cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) inhibitors etc are being extensively evaluated for their efficiency in gastric cancer. In fact, PD-1 inhibitors have been sanctioned as late late-line therapy modality for gastric cancer. The present review will focus on deciphering the link between the immune system and gastric cancer, and the alterations in the immune system that incur during the development of gastrointestinal malignancies. Also, the mechanism of evasion by tumour cells and immune checkpoints involved along with different approaches of immunotherapy being evaluated in different clinical trials will be discussed.

With increased age, the liver becomes more vulnerable to metabolic dysfunction-associated steatohepatitis (MASH) with fibrosis. Deciphering the complex interplay between aging, the emergence of senescent cells in the liver and MASH fibrosis is critical for developing treatments. Here we report an epigenetic mechanism that links liver aging to MASH fibrosis. We find that upregulation of the chromatin remodeler BAZ2B in a subpopulation of hepatocytes (HEPs) is linked to MASH pathology in patients. Genetic ablation or hepatocyte-specific knockdown of Baz2b in mice attenuates HEP senescence and MASH fibrosis by preserving peroxisome proliferator-activated receptor α (PPARα)-mediated lipid metabolism, which was impaired in both naturally aged and MASH mouse livers. Mechanistically, Baz2b downregulates the expression of genes related to the PPARα signaling pathway by directly binding their promoter regions and reducing chromatin accessibility. Thus, our study unravels the BAZ2B-PPARα-lipid metabolism axis as a link from liver aging to MASH fibrosis, suggesting that BAZ2B is a potential therapeutic target for HEP senescence and fibrosis.

A detailed understanding of aging biology and the development of anti-aging therapeutic strategies remain imperative yet inherently challenging due to the protracted nature of aging. Cellular senescence arises naturally through replicative exhaustion and is accelerated by clinical treatments or environmental stressors. The accumulation of senescent cells-defined by a loss of mitogenic potential, resistance to apoptosis, and acquisition of a pro-inflammatory secretory phenotype-has been implicated as a key driver of chronic disease, tissue degeneration, and organismal aging. Recent studies have highlighted the therapeutic promise of senolytic drugs, which selectively eliminate senescent cells. Compelling results from preclinical animal studies and ongoing clinical trials underscore this potential. However, the clinical translation of senolytics requires further pharmacological validation to refine selectivity, minimize toxicity, and determine optimal dosing. Equally important is the evaluation of senolytics' potential to restore tissue structure and function by reducing the senescent cell burden. In vitro tissue culture models offer a powerful platform to advance these efforts. This review summarizes the current landscape of in vitro systems used for inducing cellular senescence-referred to as "senescence assays"-and for screening senolytic drugs-referred to as "senolytic assays". We conclude by discussing key challenges to improving mechanistic insight, predictive accuracy, and clinical relevance in senolytic drug development, as well as emerging applications of senolytic therapies.

The aberrant expression of S100A11 has been identified in various malignancies but its functional roles and underlying mechanisms in colorectal cancer (CRC) have not been fully elucidated. Therefore, this study was designed to investigate the expression of S100A11 and its functional significance in CRC, indicating that S100A11 is significantly upregulated and correlates with poor survival outcomes in CRC. Functionally, S100A11 knockdown in CRC cell lines inhibited cell proliferation, invasion, and migration, leading to decreased tumour growth and metastasis in vivo. Mechanistic investigations revealed that S100A11 promotes cell proliferation and invasion by suppressing cell senescence. In addition, USP14 interacts with and mediates S100A11 deubiquitination. More importantly, the overexpression of S100A11 was able to partially counteract the reduction in cell proliferation caused by the knockdown of USP14. In summary, the novel regulatory axis involving USP14 and S100A11 modulates the malignant biological behavior of CRC cells through inhibiting cell senescence, therefore the interaction between USP14 and S100A11 represents a promising therapeutic target in CRC.

Immunosenescence is the dysfunction of the immune system that occurs with age, a process that is complex and characterized by several features, of which T-cell senescence is one of the key manifestations. In the tumor microenvironment, senescent T cells lead to the inability of tumor cells to be effectively eliminated, triggering immunosuppression, which in turn affects the efficacy of immunotherapy. This is a strong indication that T-cell senescence significantly weakens the immune function of the body, making individuals, especially elderly patients with cancer, more vulnerable to cancer attacks. Despite the many challenges, T-cell senescence is important as a potential therapeutic target. This review provides insights into the molecular mechanisms of T-cell senescence and its research advances in patients with cancer, especially in older adults, and systematically analyzes potential intervention strategies, including molecular mechanism-based interventions, the use of immune checkpoint inhibitors, and CAR-T cell therapy. It is hoped that this will establish a theoretical framework for T-cell senescence in the field of tumor immunology and provide a scientific and prospective reference basis for subsequent in-depth research and clinical practice on senescent T cells.

Liver fibrosis is a major global health problem without effective therapies, and targeted elimination of senescent cells is beneficial for hepatic function and organism survival. We report a new trilocked photodynamic senolytic inducer (PDSI) strategy for liver fibrosis resolution using a type-I photodynamic agent for immunogenic clearance of senescent cells. We demonstrate that this trilocked PDSI not only facilitates efficient production of superoxide anions (O2•-) in lysosomes of senescent cells for photodynamic therapy, but also permits NIR fluorescence and photoacoustic (NIRF/PA) imaging of senescent cells. Mechanistic investigation reveals that the trilocked PDSI elicited senescent cell clearance predominantly via the immunogenic necroptosis pathway. Moreover, this PDSI with a liver-targeting moiety enables high-contrast NIRF/PA imaging and effective liver fibrosis resolution in vivo. This liver-targeting PDSI exhibits remarkable immunogenic ablation of senescent cells, with enhancing dendritic cell maturation and cytotoxic T cell recruitment in liver fibrosis. Our study highlights the potential of trilocked type I PDSI for boosting immunity for senescent cell clearance and liver fibrosis treatment.

Changes in the morphology, metabolic activity, intracellular calcium (Ca2 +) transients, expression of topoisomerase-2β (Topo-2β), and senescence of human embryonic stem cells (hESCs)-derived neuronal cells on basic hESC culture media and neuronal differentiation medium at different time intervals is not clear. Hence, we aimed to investigate the morphological, cellular, biochemical, and molecular alterations in the BG01V hESC-derived neuronal cells on basic hESC culture media and neuronal differentiation media at different time intervals.

BG01V hESC-derived neuronal cells grown on basic hESC culture media and neuronal differentiation media were evaluated for morphological changes by microscopy, metabolic activity by MTT assay, cell viability by Trypan Blue exclusion assay, cellular activity by estimating the Ca2+ deposits, cellular senescence by senescence-associated beta-galactosidase (SA-β-gal) activity, and level of Topo-2β using Western blotting at different time intervals.

Contrasting to the BG01V hESCs grown on basic hESC culture media, a notable increase in the neuronal cell-like structures, neuritic outgrowth, and expression of nestin protein on neural induction was observed. Higher levels of Ca2+ deposits, metabolic activity, SA-β-gal activity, and Topo-2β expression in BG01V hESC-derived neuronal cells grown on neuronal differentiation media on day 12 compared to hESCs grown on basic hESC culture media including other days were noted.

This study suggests the increase of calcium salts reflecting the calcium activity at distinct phases of neuronal differentiation, ranging from neural induction to neurite extension. The metabolic and SA-β-gal activity of BG01V hESC-derived neuronal cells may suggest the ongoing biological aging process. Upregulation and activation of Topo-2β upon differentiation induction at the mid-phase suggest the activation of inducible gene loci and downregulation of Topo-2β at a later stage.

Senescent cells promote osteoarthritis progression through the secretion of inflammatory mediators. Preclinical studies have identified senescence-associated beta-galactosidase (β-gal) as a biomarker of senescence, but in vivo detection remains challenging. Here, we evaluated whether a β-gal responsive gadolinium (Gd) chelate can non-invasively detect β-gal expressing senescent cells with standard clinical magnetic resonance imaging (MRI) technology in vitro, ex vivo, and in vivo in porcine joints. In vitro studies showed that senescent mesenchymal stromal cells (MSCs) exhibited significant MRI signal enhancement upon incubation with the β-gal responsive Gd-chelate compared to viable control cells. In vivo, intraarticular injection of the probe into pig knee joints revealed its retention and activation by senescent cells in cartilage defects, evidenced by a significant increase in R 1 relaxation rate. MRI-based senescent cell detection holds promise for identifying patients amenable to senolytic therapies, tailoring treatment plans, and monitoring therapy response in real-time.

To facilitate effective preclinical testing of senescence treatments for osteoarthritis (OA), we have created reliable biomimetic and high-throughput models using aged human joint tissues. Moreover, concerns regarding scalability led to the concurrent development of a high-throughput human in vitro senescence cartilage organoid model. Osteochondral explants and cells for the cartilage organoid model were isolated from patients undergoing joint replacement surgery due to OA. To induce senescence, explants and organoids were subjected to radiation and/or mechanical loading. Samples were harvested; gene expression of relevant senescent and cartilage genes was measured using RT-qPCR, and protein expression was evaluated using histology. A general senescence phenotype was induced by the perturbations, as shown by senescence-associated β-galactosidase staining. In-depth gene expression analysis revealed that hyperphysiological mechanical loading upregulated gene expression of IL8 and SERPINE1, representing aspects of a senescence-associated secretory phenotype (SASP) profile. Irradiation upregulated CDKN1A, encoding p21, and downregulated LMNB1, representing a cell cycle arrest profile with the absence of a SASP response. Combining the two perturbations showed upregulation of CDKN1A, IL8, and SERPINE and downregulation of LMNB1, representing a complementary senescence model. The high-throughput human in vitro cartilage organoid senescence model showed similar effects to the irradiation explant model. In this study, we present a variety of senescence models of human aged chondrocytes that allows for rapid initial screening of anti-senescence compounds in high-throughput, as well as in-depth, characterization of post-mitotic aged chondrocytes prone to OA pathophysiology. This research advances the development of essential therapeutics for OA.

Sex disparities have been epidemiologically demonstrated in non-reproductive cancers, yet how the sex-specific intrinsic microbiome orchestrates the immune system to affect these disparities is unclear. Here we identify a subpopulation of RETNLG+LCN2+ senescence-like neutrophils (RLSNs) that preferentially accumulate in the male tumor microenvironment and exert a strong immunosuppressive effect to limit antitumor immunity, resulting in poor prognosis for patients with bladder cancer. This difference in enrichment of RLSNs between sexes can be attributed to intestinal bacterium Alistipes shahii, which preferentially populates in females rather than males. A. shahii-associated metabolite lurasidone directly targets iron sequestrator LCN2 in RLSNs. By freeing Fe2+, lurasidone induces ferroptosis, thereby eliminating RLSNs and promoting antitumor immunity in females. In males lacking A. shahii and lurasidone, RLSNs have a survival advantage. Together, these findings demonstrate that a microbiota-lurasidone-LCN2 circuit regulates sexual disparity in bladder cancer and indicates the therapeutic potential of lurasidone for male cancer patients.

Osteoarthritis (OA) is an age-related degenerative disease that affects bones and joints. The hallmark pathogenesis of OA is associated with chondrocyte senescence. Surfactant protein D (SP-D) is a member of the innate immune proteins family, which can inhibit the immune inflammatory response of chondrocytes. However, the effect of SP-D on chondrocyte senescence phenotype is poorly studied. The present study investigated the phenotypic regulation of OA chondrocyte senescence mediated by SP-D and explored the underlying molecular mechanism.

In this study, an in vitro senescence chondrocyte model was generated by subjecting chondrocytes to IL-1β treatment. Furthermore, the expression of aging-related biomarkers and mitochondrial functions in SP-D overexpressing chondrocytes was observed. Co-immunoprecipitation was conducted to verify the association between SP-D and the identifed proteins within chondrocytes. Moreover, a rat OA model was established by destabilization of the medial meniscus surgery, and the effect of SP-D on reversing the aging phenotype of OA cartilage was investigated.

The results indicated that SP-D significantly decreased senescence and enhanced mitochondrial functions in senescent chondrocytes. The RNA-sequencing analysis revealed that the SIRT3/SOD2 pathway predominantly modulated the effect of SP-D on alleviating senescence. In addition, SP-D overexpression mitigated chondrocyte senescence, suppressed senescence-associated secretory phenotype (SASP) secretion and ameliorated mitochondrial damage. In the rat OA model, SP-D inhibited aging-related pathological changes by upregulating SIRT3/SOD2 pathway, thereby protecting the cartilage tissue integrity.

These findings indicate that SP-D modulates the inhibition of chondrocyte senescence by upregulating SIRT3/SOD2 pathway. These data indicate that targeting SP-D and the SIRT3/SOD2 pathway might be a promising therapeutic strategy for OA.

Aging is a key risk factor for sarcopenia, a progressive disorder affecting skeletal muscle. One hallmark of aging is cellular senescence. To investigate cellular senescence in mouse skeletal myoblasts, we attempted to induce cellular senescence by HRasV12. Unexpectedly, HRasV12 did not induce the expression of senescence markers such as p16 and p21, and no SA-β-gal-positive cells were observed in the myoblasts. Instead, HRasV12 elevated the levels of apoptotic markers such as cleaved caspase-3, cleaved caspase-8, and the ratio of Bax to Bcl-2 in the myoblasts. These findings suggested that HRasV12 does not induce senescence, but triggers apoptotic cell death in mouse skeletal myoblasts.

Vascular aging is a major contributor to age-related cardiovascular diseases (CVDs) and type 2 diabetes mellitus (T2DM) induced early arterial aging and excessive senescent cells (SCs) burden in vessels. Inhibiting cellular senescence or eliminating SCs could effectively improve aging-related CVDs. Fisetin, a flavonoid extracted from cotinus coggygria scop, has shown potential in alleviating aging by clearing SCs. This study investigated the unexplored mechanisms and efficacy of fisetin in alleviating T2DM-related aortic aging. The T2DM mouse model was induced using a high-fat diet and low-dose streptozotocin injection. Chronic fisetin treatment's protective effects against aortic aging were assessed via senescence-associated beta-galactosidase (SA-β-Gal) staining, histopathology, and vasomotor function. RNA-sequencing and western blotting identified relevant signaling pathways and protein expression. Fisetin's effects on SCs and senescence-associated secretory phenotype (SASP) factors were evaluated through cell viability, apoptosis, and co-culture assays. Docking simulations suggested fisetin as a potential Phosphoinositide 3-kinase (Pi3k) inhibitor. In vivo, chronic fisetin treatment reduced aortic SCs burden, alleviating T2DM-related and natural aortic aging. In vitro, fisetin selectively induced apoptosis of senescent endothelial cells via regulating the Pi3k-Protein Kinase B (Akt)-B-cell lymphoma (Bcl)-2/Bcl-xl pathway and suppressed SASP and its detrimental effects. Furthermore, fisetin combined with metformin therapy showed superior anti-aging effects on T2DM-related aortic aging compared to metformin monotherapy. In conclusion, chronic fisetin treatment alleviates T2DM-related aortic aging via clearing the SCs burden and abrogating the SASP factors. Fisetin combined with metformin therapy might be a potential therapeutic strategy for T2DM-related CVDs.

Male fertility declines during aging. This process mainly affects spermatogonia and Sertoli cells, leading to impaired spermatogenesis and poor-quality sperm production. Circular RNAs (circRNAs) are covalently closed RNA molecules produced by backsplicing. In the field of male reproduction, circRNAs boast great potential in the regulation of spermatogenesis and sperm morpho-functional skills. However, their potential role in age-related male reproductive anomalies remains largely elusive. Here, we analyzed the reproductive phenotype of the aged male mouse experimental model, pointing our attention to a putative functional link between circRNAs and Sertoli cell survival. Our results confirm several testicular age-related defects including: (i) altered morphology of the seminiferous epithelium; (ii) affected spermatogenesis; and (iii) decreased sperm production. In particular, aged spermatozoa (SPZ) were decreased in number in association with low motility and abnormal morphology (sperm head anomalies and tail bents). The expression analysis of selective spermatic circRNAs demonstrated a de-regulated expression profile in Aged versus Young SPZ. Among them, we turned the lens on circAbcb9 as a spermatic circRNA potentially involved in the Sertoli cell senescence pathway via the circRNA/miRNA/mRNA network (ceRNET). Indeed, a significant shutdown of circAbcb9-dependent network associated with a prominent increase in Sertoli cell senescence occurred in Aged testis. Interestingly, circAbcb9 was also expressed in human SPZ at decreased levels in Aged men, suggesting a conserved role. Collectively, our study stimulates greater interest in circRNAs as involved in the molecular mechanisms behind the age-related effect on Sertoli cell survival, also providing new implications for fused protein in sarcoma (FUS) protein in sertolian circRNA biogenesis.

Cellular senescence refers to a condition where cells permanently cease division while maintaining metabolic activity. Doxorubicin (Dox) is known as an agent of induction of cellular senescence. This study aimed to explore the potential role of human umbilical cord mesenchymal stem cell-derived exosomes (hucMSC-Exo) in mitigating Dox induced senescent.

NIH3T3 cells were treated by various concentrations of Dox with or without hucMSC-Exo, cell morphology, viability, migration, senescence-associated SA-β-Gal staining were monitored. Cellular senescence was induced in C57BL/6J mice via administration of 5 mg/kg Doxorubicin, followed by treatment with hucMSC-Exo or metformin. Assessments included body weight, liver and kidney weight, colon length, SA-β-Gal staining of kidney and skin, molecular biomarkers of aging such as p16INK4A, p53, and p21Waf1/Clip1 to evaluate senescence status.

We found that after the treatment of exosomes or metformin improved several aging-related phenotypes in both mouse and cellular models, including increases in body weight, liver and kidney weights, and the reduction of SA-β-Gal positive cells in kidney and skin tissues as well as cell models. At the molecular level, hucMSC-Exo resulted in the downregulation of inflammatory factors and senescence markers in liver and kidney tissues as well as cell models.

Our study demonstrates hucMSC-Exo may ameliorate Dox induced senescence either in NIH3T3 cells or in mice.

P Natural killer (NK) cells function as crucial effectors in the innate immune response against tumors. Nevertheless, NK cell senescence, characterized by phenotypic and functional changes, substantially compromises their antitumor immune response. This review provides a comprehensive summary of the molecular mechanisms governing NK cell senescence and its implications for cancer immunotherapy. We propose a refined definition of NK cell senescence based on distinct biomarkers, including elevated CD57 expression, reduced cytotoxicity, and altered cytokine secretion. Moreover, we investigate the complex interactions between the tumor microenvironment (TME) and NK cell senescence, highlighting the influence of chronic inflammation, immunosuppressive cytokines, and persistent tumor antigenic stimulation. Additionally, this review underscores the potential utility of senescent NK cells as biomarkers for assessing antitumor efficacy and examines the adverse effects of NK cell senescence on cancer immunotherapy. Lastly, we summarize current approaches to mitigate NK cell senescence, such as gene editing techniques and cytokine modulation, which may enhance the efficacy of NK cell-based immunotherapies. By establishing a comprehensive framework for understanding NK cell senescence within the TME, this review aims to guide future research and the development of innovative therapeutic strategies targeting senescent NK cells to improve cancer immunotherapy outcomes.

Glycosidases participate in modulating a number of biological processes, and their overexpression is a hallmark of several human diseases. Considering the localization of glycosidases predominantly in the lysosomes, it is imperative to develop molecular probes that are resistant to interference from acidic pH. Herein, tricyanofuran-based long-wavelength fluorogenic probes are synthesized, and it is demonstrated that the introduction of bromine to the ortho-position of the phenol alcohol of the probe substantially enhances its fluorescence over an acidic pH range of 3.0-10.0. These probes, when modified with glycosyl substrates, have proved applicable for the sensitive fluorogenic detection of glycosidases under acidic pH, and fluorescence-based imaging of endogenous β-galactosidase and β-glucosidase activities in live cells. The imaging results are validated by quantitative real-time polymerase chain reaction and immunoblotting.

Glioblastomas (GBM) are routinely treated with high doses of ionizing radiation (IR), yet these tumors recur quickly, and the recurrent tumors are highly therapy resistant. Here, we report that IR-induced senescence of tumor cells counterintuitively spurs GBM recurrence, driven by the senescence-associated secretory phenotype (SASP). We find that irradiated GBM cell lines and patient derived xenograft (PDX) cultures senesce rapidly in a p21-dependent manner. Senescent glioma cells upregulate SASP genes and secrete a panoply of SASP factors, prominently interleukin IL-6, an activator of the JAK-STAT3 pathway. These SASP factors collectively activate the JAK-STAT3 and NF-κB pathways in non-senescent GBM cells, thereby promoting tumor cell proliferation and SASP spreading. Transcriptomic analyses of irradiated GBM cells and the TCGA database reveal that the cellular inhibitor of apoptosis protein 2 (cIAP2), encoded by the BIRC3 gene, is a potential survival factor for senescent glioma cells. Senescent GBM cells not only upregulate BIRC3 but also induce BIRC3 expression and promote radioresistance in non-senescent tumor cells. We find that second mitochondria-derived activator of caspases (SMAC) mimetics targeting cIAP2 act as novel senolytics that trigger apoptosis of senescent GBM cells with minimal toxicity towards normal brain cells. Finally, using both PDX and immunocompetent mouse models of GBM, we show that the SMAC mimetic birinapant, administered as an adjuvant after radiotherapy, can eliminate senescent GBM cells and prevent the emergence of recurrent tumors. Taken together, our results clearly indicate that significant improvement in GBM patient survival may become possible in the clinic by eliminating senescent cells arising after radiotherapy.

Susceptibility to cartilage degeneration increases in an age-dependent manner and older cartilage exhibits increased catabolic factor expression leading to osteoarthritis (OA). While inhibition of cellular senescence can prevent age-related diseases, the understanding of the regulators governing cartilage senescence and the potential for senolytic intervention remains limited. Here, in vitro and in vivo results are reported, demonstrating for the first time that the transcriptional regulator, ZMIZ1, is upregulated in aged and OA cartilage, and that it acts through GATA4 to accelerate chondrocyte senescence and trigger cartilage deterioration. Furthermore, it is shown that K-7174 interferes with the ZMIZ1-GATA4 interaction and effectively hampers cartilage senescence and OA. It is proposed that inhibition of the ZMIZ1-GATA4 axis could be a valuable strategy for eliminating senescent chondrocytes and impeding OA development and that the relevant inhibitor, K-7174, could potentially be developed as a senolytic drug for managing cartilage senescence and age-related degeneration.

Osteoarthritis (OA) is a long-term degenerative joint disease worsening over time. Aging and chondrocyte senescence contribute to OA progression. MicroRNAs have been confirmed to regulate different cellular processes. They contribute to OA pathology and may help to identify novel biomarkers and therapies for OA.

This study used bioinformatics and experimental investigations to analyze and validate differentially expressed miRNAs in OA that might affect chondrocyte apoptosis and senescence.

miR-6779 was found to be significantly down-regulated in OA. Seventy-six of the predicted and miR-6779 targeted genes and the OA-associated disease genes overlapped, and these were enriched in cell proliferation, cell apoptosis, and cell cycle. miR-6779 overexpression remarkably attenuated IL-1β effects on chondrocytes by reducing MMP3 and MMP13 levels, promoting cell apoptosis, suppressing cell senescence, and increasing caspase-3, caspase-9 and reducing P16 and P21 levels. miR-6779 targeted inhibition of X-linked inhibitor of apoptosis protein (XIAP) expression. XIAP knockdown partially improved IL-1β-induced chondrocyte senescence and dysfunction. Lastly, when co-transfected with a miR-6779 agomir, the XIAP overexpression vector partially attenuated the effects of miR-6779 overexpression on chondrocytes; miR-6779 improved IL-1β-induced senescence and dysfunction in chondrocytes through targeting XIAP.

miR-6779 is down-regulated, and XIAP is up-regulated in OA cartilage and IL-1β-treated chondrocytes. miR-6779 inhibits XIAP expression, thereby promoting senescent chondrocyte cell apoptosis and reducing chondrocyte senescence and ECM loss through XIAP.

Cellular senescence is an irreversible cell cycle arrest caused by various stressors that damage cells. Over time, senescent cells accumulate and contribute to the progression of multiple age-related degenerative diseases. It is believed that these cells accumulate partly due to their ability to evade programmed cell death through the development and activation of survival and antiapoptotic resistance mechanisms; however, many aspects of how these survival mechanisms develop and activate are still unknown. By analyzing transcriptomic signature profiles generated by the LINCS L1000 project and using network-based methods, we identified various genes that could represent new senescence-related survival mechanisms. Additionally, employing the same methodology, we identified over 600 molecules with potential senolytic activity. Experimental validation of our computational findings confirmed the senolytic activity of Fluorouracil, whose activity would be mediated by a multitarget mechanism, revealing that its targets AURKA, EGFR, IRS1, SMAD4, and KRAS are new senescent cell antiapoptotic pathways (SCAPs). The development of these pathways could depend on the stimulus that induces cellular senescence. The SCAP development and activation mechanisms proposed in this work offer new insights into how senescent cells survive. Identifying new antiapoptotic resistance targets and drugs with potential senolytic activity paves the way for developing new pharmacological therapies to eliminate senescent cells selectively.

The incidence of inflammatory bowel disease among the elderly has significantly risen in recent years, posing a growing socioeconomic burden to aging societies. Moreover, non-gastrointestinal diseases, also prevalent in this demographic, have been linked to intestinal barrier dysfunction, thus highlighting the importance of investigating aged-mediated changes within the human gut. While gastrointestinal pathology often involves an impaired gut barrier, the impact of aging on the human gastrointestinal barrier function remains unclear. To explore the effect of senescence, a key hallmark of aging, on gut barrier integrity, we established and evaluated an in vitro gut-on-a-chip model tailored to investigate barrier changes by the integration of an impedance sensor. Here, a microfluidic gut-on-a-chip system containing integrated membrane-based electrode microarrays is used to non-invasively monitor epithelial barrier formation and senescence-mediated changes in barrier integrity upon treating Caco-2 cells with 0.8 μg mL-1 doxorubicin (DXR), a chemotherapeutic which induces cell cycle arrest. Results of our microfluidic human gut model reveal a DXR-mediated increase in impedance and cell hypertrophy as well as overexpression of p21, and CCL2, indicative of a senescent phenotype. Combined with the integrated electrodes, monitoring ∼57% of the cultivation area in situ and non-invasively, the developed chip-based senescent-gut model is ideally suited to study age-related malfunctions in barrier integrity.

The impact of gravity is a basic force determining our existence on Earth. Changes in orientation with respect to the gravity vector trigger alternating mechanical forces on organisms, organs, and cells. In the intestines of mammals, epithelial cells are continuously exposed to changed orientations to gravity. In this study, we employed dynamic cultivation systems to mimic the load changes and the resulting mechanical forces. The morphological and functional response of non-cancer-derived porcine epithelial cell lines IPEC-1 and IPEC-J2 was analyzed. We found that dynamic growth conditions affect morphology in the enterocyte model IPEC-1 but not in IPEC-J2. Changes in IPEC-1 were accompanied by modifications of the distribution and structure of the F-actin cytoskeleton rather than the amount. The structure of the apical brush border and the tight junction system seemed to be largely unaffected; however, a robust decrease in transepithelial resistance was found in IPEC-1 and partially in IPEC-J2. We further detected an increase in Ki67, pointing towards accelerated proliferation. In line with this finding, we detected a doubling of cellular mitochondrial respiration, which was not linked to a general increase in the respiratory chain capacity. Dynamic cultivation of confluent epithelial cell layers did not evoke signs of senescence. In summary, we identified the mechanical load cycle as a relevant parameter for the modulation of the morphological structure and physiological behaviour of intestinal epithelial cells.

Targeting senescent cells and the factors that accelerate this pathological state has recently emerged as a novel field in medicinal chemistry. As attention shifts to synthetic substances, studies on natural agents are often overlooked. In this paper, we present a detailed computational modeling study that encompasses quantum mechanics and molecular dynamics to elucidate the senotherapeutic activity of fisetin, a natural flavonoid. The mitochondrial environment, serving as a proxy for senescence, received special attention. Throughout the study, fisetin's outstanding geroprotective properties-exhibiting significant potential against ⋅OOH, O2⋅-, and ⋅OH radicals, surpassing those of Trolox or ascorbate-were identified. Furthermore, fisetin demonstrated a high capacity to restore oxidatively damaged biomolecules to their pristine forms, thereby renewing the functionality of proteins and amino acids. The senolytic properties were examined in terms of Bcl-2 and Bcl-xL inhibition. The results indicated that fisetin not only binds effectively to these proteins but also, with appropriate modifications, may exhibit specific selectivity toward either target. This study highlights fisetin's remarkable activity in these areas and provides a molecular description of the underlying processes, paving the way for future research.

Transforming growth factor-β (TGF-β) signaling and cellular senescence are key hallmarks of hepatocellular carcinoma (HCC) pathogenesis. Despite provoking senescence-associated growth arrest in epithelial HCC cells, elevated TGF-β activity paradoxically correlates with increased aggressiveness and poor prognosis in advanced tumors. Whether the transition between these dichotomous functions involves modulation of the senescence phenotype during disease progression remains elusive. Exploiting the epithelial HCC cell line Huh7 as a robust model, we demonstrate that chronic exposure to TGF-β prompts escape from Smad3-mediated senescence, leading to the development of TGF-β resistance. This altered state is characterized by an optimal proliferation rate and the acquisition of molecular and functional traits of less-differentiated mesenchymal cells, coinciding with differential growth capacity in 2D and 3D culture conditions, epithelial-to-mesenchymal transition (EMT), and increased invasiveness in vitro, and metastasis in vivo. Mechanistically, resistant cells exhibit defective activation and nuclear trafficking of Smad molecules, particularly Smad3, as ectopic activation of the TGF-β/Smad3 axis is able to reinstate TGF-β sensitivity. An integrated transcriptomic landscape reveals both shared and distinct gene signatures associated with senescent and TGF-β resistant states. Importantly, genetic ablation and molecular studies identify microtubule affinity regulating kinase 1 (MARK1) and glutamate metabotropic receptor 8 (GRM8) as critical modulators of the resistance phenomenon, potentially by impairing spatiotemporal signaling dynamics of Smad activity. Our findings unveil a novel phenomenon wherein epithelial HCC cells may exploit senescence plasticity as a mechanism to oppose TGF-β anti-tumor responses and progress towards more aggressive HCC phenotypes.

The body's innate immune system plays a pivotal role in identifying and eliminating cancer cells. However, as the immune system ages, its functionality can deteriorate, becoming dysfunctional, inefficient, or even inactive-a condition referred to as immunosenescence. This decline significantly increases the risk of malignancies. While the pro-cancer effects of T-cell aging have been widely explored, there remains a notable gap in the literature regarding the impact of aging on innate immune cells, such as macrophages and neutrophils. This review seeks to address this gap, with emphasis on these cell types. Furthermore, although certain cancer immunotherapies, including immune checkpoint inhibitors (ICIs), have demonstrated efficacy across a broad spectrum of cancers, elderly patients are less likely to derive clinical benefit from these treatments. In some cases, they may even experience immune-related adverse events (irAEs). While senolytic strategies have shown promise in exerting anti-cancer effects, their adverse reactions and potential off-target effects present significant challenges. This review aims to elucidate the pro-cancer effects of immunosenescence, its implications for the efficacy and safety of ICIs, and potential anti-aging treatment strategies. In addition, optimizing anti-aging therapies to minimize adverse reactions and enhance therapeutic outcomes remains a critical focus for future research endeavors.

Anemarrhena asphodeloides Bge. (AAB), a traditional medicinal herb, has a long history of delaying the aging process. Yet, the anti-aging effects of its polysaccharides have not been thoroughly investigated. This study marks the first exploration of the anti-aging activity of Anemarrhena asphodeloides Bge. polysaccharides (AABP). The MW of AABP-1a was determined to be 210.062 kDa, with a composition consisting predominantly of glucose and mannose in a molar ratio of approximately 4:1. The backbone of AABP-1a was mainly composed of →4)-2Ac-β-Man(1→ and →4)-β-Glc(1→ and a small amount of branched →4,6)-β-Glc(1→ and →3,4)-β-Glc(1→, the branching part was composed of →6)-β-Glc(1→ and t-α-Glc(1→. AABP-1a has antioxidant capacity and can improve cell cycle arrest mediated by senescence markers such as p53, p21, p16 and SASP, and reduce the accumulation of damaged DNA. In addition, it could reduce the activity of SA-β-Gal in zebrafish, prolong the lifespan of C. elegans and reduce the expression of lipofuscin. This study found a glucomannan and demonstrated its anti-aging activity in various aging models. These results provide a theoretical basis for further study of the anti-aging effect of AAB.

A complete understanding of aging is a critical first step in treating age-related diseases and postponing aging dysfunction in the context of an aging global population. Aging in organisms is driven by related molecular alterations that gradually occur in many organs. There has previously been a wealth of knowledge of how cells behave as they age, but when aging is investigated as a disease, the discovery and selection of aging biomarkers and how to diagnose the aging of the organism are crucial. Here, we provide a summary of the state of the field and suggest future potential routes for research on organ senescence markers. We reviewed research on biomarkers of risk of aging from the perspective of organ aging and summarized the biomarkers currently used on three scales. We emphasize that the combination of traditional markers with emerging multifaceted biomarkers may be a better way to diagnose age-related diseases.

Senescent endothelial cells (EC) are key players in the pathophysiology of cardiovascular diseases and are characterized by a reduced angiogenic and regenerative potential. Therefore, targeting these cells has been suggested as an effective therapeutic strategy to reduce vascular disease burden and potentially improve health and lifespan of humans. Here, we aimed to establish a pharmacological, partial reprogramming strategy to improve replicative senescent endothelial cell function in the context of angiogenesis. We demonstrate that our treatment improves tube formation and sprouting capacity but also increases proliferation and migration capacity in vitro. Further, inflammation and DNA damage were reduced in the replicative senescent cells. These processes were initiated by a short and timely-restricted overexpression of the Yamanaka-factors induced by our pharmacological strategy. The advantage of these compounds is that they are FDA approved in their respective concentrations which could pave the way for use in a clinical setting.

Therapy-induced senescence (TIS) alters calcium (Ca²⁺) flux and Mitochondria-ER Contact Sites (MERCS), revealing critical vulnerabilities in senescent cells. In this study, TIS was induced using Doxorubicin and Etoposide, resulting in an increased MERCS contact surface but a significant reduction in ER-mitochondria Ca²⁺ flux. Mechanistically, TIS cells exhibit decreased expression of IP3R isoforms and reduced interaction between type 1 IP3R and VDAC1, impairing Ca²⁺ transfer. This flux is crucial for maintaining the viability of senescent cells, highlighting its potential as a therapeutic target. Inhibition of ER-mitochondria Ca²⁺ flux demonstrates senolytic effects both in vitro and in vivo, offering a novel strategy for targeting senescent cells.

The functional capacity of highly proliferative cell populations changes with age. Here, we report that the proliferative capacity of canine lung mesenchymal stromal cells (LMSCs) declines with increasing age of the donor. However, other functional changes such as reduced autophagy, reduced migration/wound healing, increased production of reactive oxygen species, and increased senescence are not significantly altered with increasing age. Furthermore, transcriptomic profiling suggests minimal age-related changes. These data suggest that the reduced proliferative capacity of lung LMSCs isolated from aging donors may be associated with reversible cell cycle arrest (quiescence), rather than irreversible cell cycle arrest (senescence). Similar findings have been reported in other systems, including neural and muscle stem cells that are associated with low turnover-rate tissues.

The microenvironment of intervertebral disc degeneration (IVDD) is characterized by oxidative stress, leading to the senescence of nucleus pulposus-derived mesenchymal stem cells (NPMSCs). The purpose of this study was to investigate the competitive endogenous RNA mechanism involved in the senescence of NPMSCs induced by tert-butyl hydroperoxide (TBHP).

Bioinformatic analysis identified differentially expressed circRNAs. Interactions among circSPG21, miR-217, and the NAD-dependent protein deacetylase sirtuin-1 (SIRT1) were validated through dual-luciferase assays, RNA fluorescence in situ hybridization and RNA immune precipitation. β-Gal staining, EdU staining, Western blotting, JC-1 assays, cell cycle analysis, and quantitative reverse transcription PCR (RT‒qPCR) were used to examine the functions of these molecules in TBHP-induced senescent NPMSCs. The therapeutic effects of circSPG21 were evaluated in a rat IVDD model.

CircSPG21 expression was significantly decreased in both human and rat IVDD tissues, whereas miR-217 was upregulated and SIRT1 was downregulated. Overexpression of circSPG21 alleviated NPMSC senescence by reducing P21 and P53 levels and restoring mitophagy through Parkin. The protective effects of circSPG21 were mediated through the miR-217/SIRT1 axis, as SIRT1 knockdown attenuated these benefits. CircSPG21 also ameliorated disc degeneration in the IVDD rat model, highlighting its potential as a therapeutic target.

CircSPG21 reduces oxidative stress-induced NPMSC senescence through the miR-217/SIRT1 axis and mitophagy, providing new insights into IVDD and identifying circSPG21 as a potential therapeutic target for disc degeneration.

Major risk factors of head and neck squamous cell carcinoma (HNSCC) are tobacco use and human papillomavirus (HPV). HPV E6 oncoprotein leads to p53 degradation, whereas HPV-negative cancers are frequently associated with TP53 mutations. Peposertib is a potent and selective, orally administered small-molecule inhibitor of the catalytic subunit of the DNA-dependent kinase (DNA-PKcs), a key regulator of nonhomologous end joining (NHEJ). NHEJ inhibition along with irradiation (IR)-induced DNA double-strand breaks has the potential to increase antitumor treatment efficacy. In this study, we investigated the responses of a panel of HNSCC models with distinct HPV and p53 status to treatments with IR, DNA-PKcs inhibition, and their combination in vitro and in vivo. IR-induced DNA damage combined with peposertib administration shortly before IR results in decreased cell viability and proliferation and causes DNA repair delay in all studied HNSCC cell lines. However, our data confirm that the actual cell fate upon this treatment is determined by cellular p53 and/or HPV status. Cells lacking functional p53 due to its degradation by HPV or due to a loss-of-function mutation are arrested in the G2/M phase of the cell cycle and eliminated by apoptosis, whereas p53-proficient HNSCC cell lines preferentially undergo senescence. This is also recapitulated in vivo, where HPV+ UD-SCC-2 xenografts display stronger and more durable responses to the combined treatment as compared with p53 wild-type UM-SCC-74A tumors. In conclusion, DNA-PKcs inhibitor peposertib should be further studied as a potential radiosensitizer for HNSCCs, taking into consideration the genetic background and the HPV status of a particular tumor.

Senolytic drugs raise the expectation that they can specifically eliminate a subset of senescent cells in a given tissue. In this study, we have exemplarily analyzed if a 3-day treatment of human blood samples in vitro would reduce age-associated biomarkers, with a particular focus on epigenetic age-predictions. Of eight tested compounds, JQ1, RG7112, nutlin-3a, and AMG232 reduced epigenetic age, indicating that this approach may be useful in drug screening for senolytic compounds.