Senolytic effects of first and second generation BCL-xL/BCL-2 dual degraders

Objective: To investigate the number, type, and functional heterogeneity of senescent cells in the radiation-induced skin wounds in mice. Methods: The study was an experimental study. Forty male p16-diphtheria toxin receptor-tdTomato (p16DTR/Tom) transgenic mice aged 6-8 weeks, which could be used to trace senescent cells, were divided into 35 Gy group and 50 Gy group (with 20 mice in each group) according to the random number table method, and 35 or 50 Gy X-ray irradiation was applied to the skin of the right hind limb of the mice to establish 3 or 4 degree of radiation-induced skin injury model, respectively. The positive area percentage of senescent cells in the wound tissue of mice in two groups was detected before irradiation and at 10, 20, and 30 d after irradiation; at 10 d after irradiation, the co-localization of endothelial cells (ECs), mononuclear macrophages (MMs), keratinocytes (KCs), fibroblasts (Fbs) and senescent cells in the wound tissue of mice in 50 Gy group was observed by immunofluorescence method. Nine male p16DTR/Tom transgenic mice aged 6-8 weeks were divided into unirradiated group without any treatment and 35 Gy group and 50 Gy group with the same treatment as above (with 3 mice in each group) according to the random number table method. The wound tissue of mice in 35 Gy group and 50 Gy group at 10 d after irradiation and the normal skin tissue of mice in unirradiated group at the corresponding time point was taken, and the senescence percentages of KCs, Fbs, ECs, and MMs were detected by flow cytometry. Bioinformatics analysis was performed on publicly available single-cell transcriptome sequencing data from normal skin tissue of healthy rats (setting as control group) and mixed wound tissue of rats for 7 and 14 d after irradiation with 30 Gy electron beams (setting as irradiated group), and the two groups of cells were subjected to senescence assessment to screen for senescent cells, the correlation between the expression profiles of senescence-associated secretory phenotypes (SASPs) of various types of senescent cells in irradiated group was analyzed, and the differentially expressed genes (DEGs) with significantly differential expression between the senescent cells in irradiated group and the corresponding normal cells in control group were screened for gene ontology (GO) enrichment analysis. Results: The positive area percentage of senescent cells in the wound tissue of mice in 50 Gy group was significantly higher than that in 35 Gy group at 20 and 30 d after irradiation (with t values of -5.56 and -5.48, respectively, P<0.05). ECs, MMs, KCs, and Fbs co-localized with senescent cells in the wound tissue of mice in 50 Gy group at 10 d after irradiation. The senescence percentages of KCs, Fbs, ECs, and MMs in the wound tissue of mice in 50 Gy group at 10 d after irradiation were (21.07±9.49)%, (16.10±3.27)%, (16.90±5.29)%, and (34.13±8.76)%, respectively, which were significantly higher than (3.58±1.13)%, (4.13±0.19)%, (3.86±1.28)%, and (10.14±4.95)% in the normal skin tissue of mice in unirradiated group at the corresponding time point, with P values all <0.05. Bioinformatics analysis showed that the senescence scores of ECs, Fbs, KCs, macrophages, monocytes, and Schwann cells in the wound tissue of rats in irradiated group were significantly higher than those in the normal skin tissue of rats in control group (with Z values of -8.71, -9.58, -7.19, -8.82, -6.66, and -2.70, respectively, P<0.05), i.e., 6 types of senescent cells were screened. The SASPs expression profiles of monocytes and macrophages in the wound tissue of rats in irradiated group were significantly correlated (r=0.83, P<0.05), but there was no statistically significant correlation between the SASPs expression profiles of the remaining types of senescent cells (P>0.05). GO enrichment analysis showed that, compared with the corresponding normal cells in control group, the significantly up-regulated DEGs of the 6 types of senescent cells in the wound tissue of rats in irradiated group were significantly enriched in the regulation of apoptosis signaling pathway, the significantly up-regulated DEGs of multiple senescent cells were significantly enriched in the myeloid cell differentiation pathway, and the significantly down-regulated DEGs of multiple senescent cells were significantly enriched in the cell division-related pathway, with P values all <0.05. Conclusions: The number of senescent cells in the wounds of mice with radiation-induced skin injury is up-regulated, and the accumulation of senescent cells is radiation dose- and time-dependent; multiple types of cells including ECs, Fbs, KCs, and MMs can undergo senescence, and there are obvious differences in the function and SASP expression profiles among various types of senescent cells.

Senescence is the result of a process that is physiological for cells. With aging, there is an increase in the number of senescent cells in organisms, and these cells produce a number of compounds known as senescence-associated secretory phenotype (SASP). These compounds secreted by senescent cells cause healthy cells in the microenvironment to exposure senescence. Therefore, preventing the accumulation of senescent cells in tissues is important for healthy cells. Senolytics are compounds that can specifically eliminate senescent cells. One of the most important differences between a cell in its normal physiological process and a senescent cell is that senescent cells are resistant to apoptosis. Although senolytics have different mechanisms of action, they jointly target the anti-apoptotic pathways of the cells and the compounds in these pathways, thereby enabling the senescent cells to undergo apoptosis and be destroyed. In addition, accumulation of senescent cells in tissues increases the risk of susceptibility to various chronic diseases, especially cardiovascular diseases, neurodegenerative diseases, cancer and kidney diseases. Therefore, it is forecasted that inhibiting the accumulation of senescent cells in tissues may reduce the risk of disease. In this review study, the effects of senolytic compound examples such as Dasatinib, Quercetin, Navitoxlac (ABT-263) and Fisetin on cardiovascular diseases, neurodegenerative diseases, cancer, kidney diseases and inflammation were briefly summarized.

The aging of the immune system, or immunosenescence, was recently verified to have a causal role in driving the aging of solid organs, while the senolytic elimination of senescent immune cells was found to effectively delay systemic aging. Our recent study also showed that immune cells in severely dystrophic muscles develop senescence-like phenotypes, including the increased expression of senescence-associated secretory phenotype (SASP) factors and senescence markers. Here we further investigated whether the specific clearance of senescent immune cells in dystrophic muscle may effectively improve the function of muscle stem cells and the phenotypes of dystrophic muscle. We observed increased percentage of senescent cells in macrophages from mdx/utro(−/−) mice (a murine model for muscular dystrophy disease, dystrophin−/−; utrophin−/−), while the treatment of mdx/utro(−/−) macrophages with senolytic drug fisetin resulted in reduced number of senescent cells. We administrated fisetin to mdx/utro(−/−) mice for 4 weeks, and observed obviously reduced number of senescent immune cells, restored number of muscle cells, and improve muscle phenotypes. In conclusion, our results reveal that senescent immune cells, such as macrophages, are greatly involved in the development of muscle dystrophy by impacting the function of muscle stem cells, and the senolytic ablation of these senescent cells with fisetin can be an effective therapeutic strategy for improving function of muscle stem cells and phenotypes of dystrophic muscles.

An E3 ligase guide to the galaxy of small-molecule-induced protein degradation

Senescence has been shown to prevent and promote tumorigenesis. [1, 2] These results are not so paradoxical. To develop and maintain, organisms rely on cellular growth and cell division. Each of these processes is spatiotemporally finely tuned and both are tightly coordinated to ensure organism homeostasis throughout life. As organism aged, deregulations of these processes appear leading to hyperplastic or degenerating diseases, such as cancer and Alzheimer disease, respectively [3]. Interestingly, these two aged-related diseases have been linked to a cellular response that yet, uncouples cellular growth from cell division: senescence. Senescence is a natural cellular response that can be triggered by various stimuli, such as telomere shortening, oncogenic stresses or unrepaired DNA damages [4]. Senescent cells grow but do not divide so that they are enlarged and restricted in number. In addition, as they do not proliferate due to the irreversible cell cycle arrest, they do not differentiate. Thus senescence modifies tissue homeostasis by profoundly impacting tissue architecture both physically and biologically. Such disorganisation leads to alteration of cell contacts thereby re-wiring cellular communication. To communicate, cells use physical interactions and diffusible factors. In that context, it is interesting to observe that senescent cells often release factors such as cytokines or growth factors. This is known as senescence associated secretory phenotype (SASP) [5]. Recently Acosta et al have shown that the TGFβ pathway mediates paracrine senescence in SASP and that this pathway and the BMP pathway are upregulated in such senescent cells [6]. Interestingly, these two pathways are involved in tissue morphogenesis during organism development. It is therefore tempting to suggest that one of the outcomes of senescence is tissue re-organisation, achieved via cell communication, to reach new homeostasis upon cellular stress. As a matter of fact, studies of senescent cancer cells suggest so. First, senescence has been shown to act as an anti-cancer barrier, both physically and biologically in preneoplastic tissue [1]. Secondly, it has been shown to promote tumorigenesis by favouring the emergence of cancer stem-like cells (CSLCs) [7]. CSLCs are rare quiescent cells. They niche in heterogeneous tumors and have, in contrast to the bulk tumor cells but similarly to normal stem cells, the ability to self renew and to differentiate. Thus, if tissue has to be re-organised upon senescence to gain minimal homeostasis for functioning, new cells have to emerge and differentiate. This can be achieved by stimulation of CSLCs by SASP factors released from senescent cancer cells. Of note, it remains unclear why CSLCs, unlike normal stem cells, do not senesce. In relation to their role in tissue architecture, it has been described that CSLCs preferentially develop, within the tissue mass, under hypoxic conditions. Interestingly, hypoxia has been shown to inhibit mTOR, which converts quiescent cells into senescent cells [8]. If experimentally verified, hypoxia could reinforce the intrinsic resistance of CSLCs by maintaining their quiescent state, while inhibiting mTOR and geroconversion of CSLCs from quiescence to senescence. It therefore appears, at least in pathological cancer tissue, that senescence, and SASP in particular, could play a pivotal role in tissue re-organisation upon cellular stress. As a consequence, depending on the cancer stage, i.e. to which extend tissue has to be re-organised upon cancer invasion, senescence could be pro or anti tumorigenic. As to whether this role in tissue re-organisation also occurs in non-pathological tissue remains to be investigated. Tissue re-organisation by senescence implies cellular communication through SASP factors. Therefore it will be interesting to investigate if senescence is accompanied by secretion of SASP factors in unicellular organisms. If not, this will strongly argue for a role of SASP in maintaining tissue homeostasis, via tissue re-organisation, in multicellular organisms.

Evaluation of senescent cells in intervertebral discs by lipofuscin staining

BCL-XL and BCL-2 are key anti-apoptotic proteins facilitating cancer survival, senescence and chemoresistance. 753b is a novel BCL-XL/BCL-2 proteolysis targeting chimera (PROTAC) that targets both BCL-XL and BCL-2 to the Von Hippel-Lindau (VHL) E3 ligase, sparing platelets that lack VHL expression. Here we studied the efficacy of 753b and its senolytic activity in leukemia. We first evaluated the sensitivity of genetically diverse 17 leukemia cell lines to BCL-XL/2 dual inhibitor ABT-263, BCL-XL PROTAC DT2216 and BCL-XL/2 PROTAC 753b. 753b induced time-dependent BCL-XL degradation within 6 hours, at concentrations lower than that of DT2216. BCL-XL was degraded by 753b in all 17 cell lines tested; BCL-2 was partially degraded in 12/17 cell lines. 753b treatment (24hrs) caused a dose-dependent reduction of viability in AML cell lines by CellTiter-Glo (CTG) assay, with IC50 ranging from 0.06-27umol/L. Six AML (KG-1, Kasumi-1, OCI-AML3, U937, TF-1; MPN-AML HEL-92) and three T-ALL (Jurkat, PF832, CCRF-CEM) were sensitive to 753b with average IC50 812nM and to ABT263 (average IC50 2,232 nM). Recent findings indicate that chemoresistance in AML is associated with chemotherapy (Ara-C)-induced senescence (Duy et al., Cancer Discovery 2021). In vitro, Ara-C induced cellular senescence (SnCs) in AML cell lines Molm14 and Kasumi-1, as manifested by increased cell size, induction of senescence-associated β-galactosidase activity, upregulation of cycle regulator proteins (p16, p21, p53) and mRNA expression of senescence-associated secretory phenotype (IL-6, IL-8, IL-1β).Conversely, 753b combined with Ara-C largely reversed chemotherapy-induced SnCs phenotype and facilitated induction of cell death in senescent AML cells. To explore the senolytic mechanism of 753b, we FACS-sorted viable leukemia cells into senescence-high or -low populations based on C12-FDG (fluorogenic substrate di-β-D-galactopyranoside). Consistent with prior data in normal HSC (Chang et al., Nat. Med. 2016), C12-FDG high population expressed higher levels of BCL-XL/2, representing therapeutic target for 753b. To study pre-clinical activity of 753b in primary AML, we exposed freshly isolated blasts from 16 AML patients to concentration range of 753b. 753b potently reduced viability of primary AML with median IC50 values of 228 nmol/L, ranging between 18 - 2,291 nmol/L (13/16 with IC50 below 450 nmol/L). Consistent with cell line data, 753b was more potent degrader of BCL-XL and apoptosis inducer compared with DT2216. BCL-2 degradation was seen in 3 out of 5 samples tested. 753b at 1 umol/L induced apoptotic cell death in both, bulk AML blasts and CD34+ stem/progenitor cells (mean specific apoptosis: 63.9% vs 52.4%, n=7). In summary, BCL-XL/2 PROTAC 753b reduced viability by inducing apoptosis in AML cell lines and in the majority of primary AML samples. Targeting BCL-XL effectively eliminated chemotherapy-induced senolytic cells. In vivo experiments in the cell line- and patient-derived xenografts of 753b combined with chemotherapy are ongoing and will be presented. Citation Format: Yannan Jia, Qi Zhang, Weiguo Zhang, Michael Andreeff, Nitin Jain, Helen Ma, Peiyi Zhang, Guangrong Zheng, Daohong Zhou, Marina Konopleva. Targeting BCL-XL/BCL-2 by PROTAC 753b effectively eliminates AML cells and enhances efficacy of chemotherapy by targeting senescent cells [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2021 Oct 7-10. Philadelphia (PA): AACR; Mol Cancer Ther 2021;20(12 Suppl):Abstract nr CC09-01.

Senescence, largely initiated by unrepaired DNA damage, is initially sustained by upregulated p53. Although senescent cells enter proliferative arrest, early p53 supression may result in senescent cells re-entering the cell cycle. Senescent cells exhibit a senescence-associated secretory phenotype (SASP) that impacts the cell microenvironment, often promoting cell transformation. SASP molecular composition may be cell-specific and dependant on the type of SASP-producing cell. As growth hormone (GH) is induced by DNA damage, we elucidated whether GH is induced in senescent cells. Non-pituitary GH (npGH) synthesized locally in peripheral tissues is identical to endocrine GH1 produced by the pituitary and acts through autocrine/paracrine mechanisms via the widely expressed GH receptor that recognizes both pituitary GH and npGH ligands. We show that npGH is induced in aging human colon tissue, and in human non-tumorous colon cells and in human 3-dimensional intestinal organoids in response to oncogene-, therapy-, and/or replicative-induced senescence. Furthermore,DNA-damage-induced npGH is secreted from senescent cells, constituting a SASP component. In senescent cells, DNA damage is not repaired with fidelity, and we show that induced npGH suppresses DNA damage responses by attenuating phosphorylation of ATM, DNA-PKc, p53 and Chk2, resulting in p53 suppression and accumulation of damged DNA. Autocrine npGH also triggers senescent cell proliferation with increased Ki67 and BrdU incorporation. As proliferating cells with accumulated unrepaired DNA damage may acquire oncogenic mutations,we assessed npGH actions on cell transformation. We show that senescent colon cells expressing npGH form colonies in soft agar,while GH depletion by shRNA downregulates Ki67 and decreases colony formation and size, suggesting that npGH enables senescent cell transformation. Consistent with a SASP function, induced paracrine npGH also suppresses the p53/p21 pathway, triggering proliferation and exacerbates DNA damage in neighboring non-senescent cells. To further explore mechanisms underlying npGH induction we tested the role of the SASP chemokine CXCL1 which attracts immune effectors to eliminate senescent cells. CXCl1 is shown to induce npGH in senescent hNCC and in intestinal organoids, while GH, in turn, suppresses CXCL1, likely by inhibiting NFκB, a CXCL1 transcription factor. Both colon CXCL1 and NFκB are more abundant in GH-receptor knockout mice devoid of GH signalling, while mice bearing GH-secreting xenografts exhibit decreased colon CXCL1 abundance. Conclusions: The results elucidate a heretofore unappreciated GH action, whereby npGH, as a SASP component, attenuates senescent cell elimination by inhibiting CXCL1, and contributes to a tissue microenvironment favoring age-associated DNA damage accumulation and epithelial cell transformation. Citation Format: Vera Chesnokova, Svetlana M. Zonis, Robert Barrett, Shlomo Melmed. Growth hormone as a SASP component [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5683.

Senescent cells accumulate in aged tissue and are causally linked to age-associated tissue degeneration. These non-dividing, metabolically active cells are highly secretory and alter tissue homeostasis, creating an environment conducive to metastatic disease progression. IL-1α is a key senescence-associated (SA) proinflammatory cytokine that acts as a critical upstream regulator of the SA secretory phenotype (SASP). We established that SA shifts in steady-state H2O2 and intracellular Ca(2+) levels caused an increase in IL-1α expression and processing. The increase in intracellular Ca(2+) promoted calpain activation and increased the proteolytic cleavage of IL-1α. Antioxidants and low oxygen tension prevented SA IL-1α expression and restricted expression of SASP components IL-6 and IL-8. Ca(2+) chelation or calpain inhibition prevented SA processing of IL-1α and its ability to induce downstream cytokine expression. Conditioned medium from senescent cells treated with antioxidants or Ca(2+) chelators or cultured in low oxygen markedly reduced the invasive capacity of proximal metastatic cancer cells. In this paracrine fashion, senescent cells promoted invasion by inducing an epithelial-mesenchymal transition, actin reorganization, and cellular polarization of neighboring cancer cells. Collectively, these findings demonstrate how SA alterations in the redox state and Ca(2+) homeostasis modulate the inflammatory phenotype through the regulation of the SASP initiator IL-1α, creating a microenvironment permissive to tumor invasion.

During human aging, decrease of NAD+ levels is associated with potentially reversible dysfunction in the liver, kidney, skeletal and cardiac muscle, endothelial cells, and neurons. At the same time, the number of senescent cells, associated with damage or stress that secretes proinflammatory factors (SASP or senescence-associated secretory phenotype), increases with age in many key tissues, including the kidneys, lungs, blood vessels, and brain. Senescent cells are believed to contribute to numerous age-associated pathologies and their elimination by senolytic regimens appears to help in numerous preclinical aging-associated disease models, including those for atherosclerosis, idiopathic pulmonary fibrosis, diabetes, and osteoarthritis. A recent report links these processes, such that decreased NAD+ levels associated with aging may attenuate the SASP potentially reducing its pathological effect. Conversely, increasing NAD+ levels by supplementation or genetic manipulation, which may benefit tissue homeostasis, also may worsen SASP and encourage tumorigenesis at least in mouse models of cancer. Taken together, these findings suggest a fundamental trade-off in treating aging-related diseases with drugs or supplements that increase NAD+. Even more interesting is a report that senescent cells can induce CD38 on macrophages and endothelial cells. In turn, increased CD38 expression is believed to be the key modulator of lowered NAD+ levels with aging in mammals. So, accumulation of senescent cells may itself be a root cause of decreased NAD+, which in turn could promote dysfunction. On the contrary, the lower NAD+ levels may attenuate SASP, decreasing the pathological influence of senescence. The elimination of most senescent cells by senolysis before initiating NAD+ therapies may be beneficial and increase safety, and in the best-case scenario reduce the need for NAD+ supplementation.

Poster 206: TIPE2 Mitigates the Histopathology of Osteoarthritis inAn Accelerate Aging Mouse Model

Brain tumors are the second most common malignancy diagnosed in children, with low-grade gliomas (LGG) being the most common childhood brain tumor, and pilocytic astrocytoma (PA) the most common LGG. LGGs are typically driven by aberrant MAPK pathway activation commonly induced by BRAF fusions or mutations. These genetic alterations activate the tumor-suppressive mechanism oncogene-induced senescence (OIS), resulting in growth arrest of transformed cells. OIS has been shown to be regulated by a complex network of inflammatory molecules, referred to as the senescence-associated secretory phenotype (SASP). Single markers of OIS have been detected in primary PAs, but its functional role in PA remains unknown to date. A patient-derived PA cell line with a BRAF fusion was generated via lentiviral transduction with a doxycycline-inducible construct coding for the SV40 Large T antigen (SV40-TAg). This novel PA model, DKFZ-BT66, enabled the analysis of the growth-arrested OIS state of PA cells as well as the proliferating state during SV40-TAg expression. Both conditions were characterized and analyzed by means of gene expression profiling (GEP), western blot, ELISA and cell viability testing via automated trypan blue exclusion staining. Primary PA material was analyzed by GEP as well as a multiplex assay. The SASP was upregulated in the OIS state of the human PA cell line DKFZ-BT66 as well as in primary human and murine PAs. Conditioned medium of senescent cells was shown to arrest growth and induce the senescence-characteristic enlarged cellular phenotype in proliferating PA cells. The SASP factors IL1B and IL6 were both upregulated and secreted by senescent PA cells and their respective pathways were shown to be regulated during OIS. Treatment of proliferating DKFZ-BT66 cells with recombinant IL1B (rIL1B), but not rIL6, reduced cell growth of proliferating PA cells. Both SASP expression as well as changes in cell morphology, reminiscent of the enlarged senescent phenotype, were induced by rIL1B treatment. However, neither pharmacological nor shRNA-mediated inhibition of the IL1 or IL6 pathway led to a bypass of the OIS state in the DKFZ-BT66 cell line. Treatment with the anti-inflammatory drug dexamethasone induced regrowth of senescent DKFZ-BT66 cells and suppressed SASP gene expression. The clinical relevance of the SASP in PA was confirmed by the identification of two patient cohorts with differing clinical outcome related to SASP expression. Elevated expression of the SASP as well as of IL1B alone was predictive for favorable progression-free survival (PFS) in PA patients independent of tumor resection status. To exploit OIS therapeutically, DKFZ-BT66 cells were treated with senolytic BCL2 family member inhibitors, specifically targeting senescent cells. Senescent PA cells were more sensitive to senolytics in comparison to proliferating DKFZ-BT66 cells or normal human astrocytes. In summary, the SASP was shown to regulate OIS in pediatric PA, with IL1B as an important mediator. Elevated SASP expression was prognostic for a favorable PFS in the analyzed cohort and will have to be validated as a prognostic marker in prospective clinical trials. The combination of senolytic agents, targeting senescent PA cells, together with chemotherapy, targeting cycling PA cells, may be a novel therapeutic approach and will have to be evaluated in further preclinical studies.

Ganoderma lucidum (G. lucidum) is a famous medicinal mushroom that has been reported to prevent and treat a variety of diseases. Different extractions from G. lucidum have been used to manage age-related diseases, including cancer. Nevertheless, the senolytic activity of G. lucidum against senescent cancer cells has not been investigated. Although cellular senescence causes tumor growth inhibition, senescent cells promote the growth of the neighboring tumor cells through paracrine effects. Therefore, the elimination of senescent cells is a new strategy for cancer treatment. In this study, senescence was triggered in HCC cells by the chemotherapeutic agent Adriamycin (ADR), and subsequently, cells were treated with TC to assess its senolytic activity. We found for the first time that the triterpenoid complex (TC) from G. lucidum had senolytic effect, which could selectively eliminate adriamycin (ADR)-induced senescent cells (SCs) of hepatocellular carcinoma (HCC) cells via caspase-dependent and mitochondrial pathways-mediated apoptosis and reduce the levels of senescence markers, thereby inhibiting the progression of cancers caused by SCs. TC could block autophagy at the late stage in SCs, resulting in a significant activation of TC-induced apoptosis. Furthermore, TC inhibited the senescence-associated secretory phenotype (SASP) in SCs through the inhibition of NF-κB, TFEB, P38, ERK, and mTOR signaling pathways and reducing the number of SCs. Sequential administration of ADR and TC in vivo significantly reduced tumor growth and reversed the toxicity of ADR. A triterpenoid complex isolated from G. lucidum may serve as a novel senolytic agent against SCs, and its combination with chemotherapeutic agents may enhance their antitumor efficacy.

Dissecting primary and secondary senescence to enable new senotherapeutic strategies

Cellular senescence is a distinct and definable biological state characterized by irreversible cell cycle arrest, accompanied by the activation of the DNA damage response (DDR), telomere shortening, the senescence-associated secretory phenotype (SASP), and metabolic dysfunction. While senescent cells represent only a small fraction of the total cell population in tissues, they exert a disproportionate and systemic impact on age-related cardiovascular disease (CVD) through paracrine and endocrine mechanisms. This review moves beyond a descriptive list of pathways and instead proposes a unified framework centered on how a small number of senescent cells can reprogram the cardiovascular microenvironment. We focus on the SASP as the central executor of this systemic effect, disseminating local senescence and driving chronic inflammation, fibrosis, and dysfunction across major cardiovascular cell types (cardiomyocytes, endothelial cells, fibroblasts, smooth muscle cells). We integrate key regulatory networks such as mTOR, AMPK, and Sirtuins that modulate the SASP and the senescent state. Furthermore, we discuss the translational promise of senolytics (agents that clear senescent cells) and senomorphics (agents that suppress the SASP) as novel strategies for delaying cardiovascular aging and treating age-related CVD, providing a forward-looking perspective on targeting senescence to promote cardiovascular health. Current research challenges include mechanistic complexity and limitations of animal models and in vitro systems. In the future, it is necessary to combine single-cell sequencing, metabolic intervention, and interdisciplinary technologies to analyze the heterogeneity of cellular aging, and develop early warning and precision treatment strategies based on aging biomarkers, so as to provide new ideas for delaying cardiovascular aging.