Molecular mechanisms and cardiovascular implications of cancer therapy-induced senescence

Secretory Phenotype in Peripheral Blood Mononuclear Cells of Elderly Patients with Rheumatoid Arthritis

This study aims to investigate the expression differences of peripheral blood mononuclear cells (PBMCs) in patients with elderly rheumatoid arthritis (ERA). Differentially expressed genes (DEGs) of PBMCs between young patients with RA (RA_Y) and elderly patients with RA (RA_A) were identified by RNA sequencing using the DESeq2 package, followed by bioinformatics analysis. The overlapped targets of the current DEGs and proteomic differentially expressed proteins (another set of unpublished data) were identified and further validated. The bioinformatics analysis revealed significant transcriptomic heterogeneity between RA_A and RA_Y. A total of 348 upregulated and 363 downregulated DEGs were identified. Gene functional enrichment analysis indicated that the DEGs, which represented senescence phenotype for patients with ERA, were enriched in pathways such as Phosphatidylinositol3 kinase/AKT serine-threonine protein kinase (PI3K/Akt) signaling, Mitogen-activated protein kinases (MAPK) signaling, toll-like receptor family, neutrophil degranulation, and immune-related pathways. Gene set enrichment analysis further confirmed the activation of humoral immune response pathways in RA_A. Quantitative polymerase chain reaction validated the expression of five representative DEGs such as SPTA1, SPTB, VNN1, TNXB, and KRT1 in PBMCs of patients with ERA. Patients with ERA have significant senescence phenotype differences versus the young patients. The DEGs identified may facilitate exploring the biomarkers of senescence in RA.

Sex-related differences in delayed doxorubicin-induced cardiac dysfunction in C57BL/6 mice

Cancer survivors may experience long-term cardiovascular complications due to chemotherapeutic drugs such as doxorubicin (DOX). The exact mechanism of delayed DOX-induced cardiotoxicity has not been fully elucidated. Sex is an important risk factor for DOX-induced cardiotoxicity. In the current study, we identified sex differences in delayed DOX-induced cardiotoxicity and determined the underlying molecular determinants of the observed sexual dimorphism. Five-week-old male and female mice were administered intraperitoneal injections of DOX (4 mg/kg/week) or saline for 6 weeks. Echocardiography was performed 5 weeks after the last dose of DOX to evaluate cardiac function. Thereafter, mice were sacrificed and gene expression of markers of apoptosis, senescence, and inflammation was measured by PCR in hearts and livers. Proteomic profiling of the heart from both sexes was conducted to determine differentially expressed proteins (DEPs). Only DOX-treated male, but not female, mice demonstrated cardiac dysfunction, cardiac atrophy, and upregulated cardiac expression of Nppb and Myh7. No sex-related differences were observed in DOX-induced expression of most apoptotic, senescence, and pro-inflammatory markers. However, the gene expression of Trp53 was significantly reduced in hearts of DOX-treated female mice only. The anti-inflammatory marker Il-10 was significantly reduced in hearts of DOX-treated male mice only, while the pro-inflammatory marker Il-1α was significantly reduced in livers of DOX-treated female mice only. Gene expression of Tnf-α was reduced in hearts of both DOX-treated male and female mice. Proteomic analysis identified several DEPs after DOX treatment in a sex-specific manner, including anti-inflammatory acute phase proteins. This is the first study to assess sex-specific proteomic changes in a mouse model of delayed DOX-induced cardiotoxicity. Our proteomic analysis identified several sexually dimorphic DEPs, many of which are associated with the anti-inflammatory marker Il-10.

AMPK-upregulated microRNA-708 plays as a suppressor of cellular senescence and aging via downregulating disabled-2 and mTORC1 activation

Senescence-associated microRNAs (SA-miRNAs) are important molecules for aging regulation. While many aging-promoting SA-miRNAs have been identified, confirmed aging-suppressive SA-miRNAs are rare, that impeded our full understanding on aging regulation. In this study, we verified that miR-708 expression is decreased in senescent cells and aged tissues and revealed that miR-708 overexpression can alleviate cellular senescence and aging performance. About the molecular cascade carrying the aging suppressive action of miR-708, we unraveled that miR-708 directly targets the 3'UTR of the disabled 2 (Dab2) gene and inhibits the expression of DAB2. Interestingly, miR-708-caused DAB2 downregulation blocks the aberrant mammalian target of rapamycin complex 1 (mTORC1) activation, a driving metabolic event for senescence progression, and restores the impaired autophagy, a downstream event of aberrant mTORC1 activation. We also found that AMP-activated protein kinase (AMPK) activation can upregulate miR-708 via the elevation of DICER expression, and miR-708 inhibitor is able to blunt the antiaging effect of AMPK. In summary, this study characterized miR-708 as an aging-suppressive SA-miRNA for the first time and uncovered a new signaling cascade, in which miR-708 links the DAB2/mTOR axis and AMPK/DICER axis together. These findings not only demonstrate the potential role of miR-708 in aging regulation, but also expand the signaling network connecting AMPK and mTORC1.

A new perspective in the prevention and treatment of antitumor therapy-related cardiotoxicity: Intestinal microecology

The continuous development of antitumor therapy has significantly reduced the mortality of patients with malignancies. However, the antitumor-related cardiotoxicity has become the leading cause of long-term mortality in patients with malignancies. Besides, the pathogenesis of antitumor-related cardiotoxicity is still unclear, and practical means of prevention and treatment are lacking in clinical practice. Therefore, the major challenge is how to combat the cardiotoxicity of antitumor therapy effectively. More and more studies have shown that antitumor therapy kills tumor cells while causing damage to sensitive tissues such as the intestinal mucosa, leading to the increased permeability of the intestine and the dysbiosis of intestinal microecology. In addition, the dysbiosis of intestinal microecology contributes to the development and progression of cardiovascular diseases through multiple pathways. Thus, the dysbiosis of intestinal microecology may be a potential mechanism and target for antitumor-related cardiotoxicity. We summarized the characteristics of intestinal microecology disorders induced by antitumor therapy and the association between intestinal microecological dysbiosis and CVD. And on this basis, we hypothesized the potential mechanisms of intestinal microecology mediating the occurrence of antitumor-related cardiotoxicity. Then we reviewed the previous studies targeting intestinal microecology against antitumor-associated cardiotoxicity, aiming to provide a reference for future studies on the occurrence and prevention of antitumor-related cardiotoxicity by intestinal microecology.

Exposure to Doxorubicin Modulates the Cardiac Response to Isoproterenol in Male and Female Mice

Sex is a salient risk factor in the development of doxorubicin-induced cardiotoxicity. Sex differences in the heart's ability to respond to hypertrophic stimuli in doxorubicin-exposed animals have not been reported. We identified the sexual dimorphic effects of isoproterenol in mice pre-exposed to doxorubicin. Male and female intact or gonadectomized C57BL/6N mice underwent five weekly intraperitoneal injections of 4 mg/kg doxorubicin followed by a five-week recovery period. Fourteen days of subcutaneous isoproterenol injections (10 mg/kg/day) were administered after the recovery period. Echocardiography was used to assess heart function one and five weeks after the last doxorubicin injection and on the fourteenth day of isoproterenol treatment. Thereafter, mice were euthanized, and the hearts were weighed and processed for histopathology and gene expression analysis. Doxorubicin did not produce overt cardiac dysfunction in male or female mice before starting isoproterenol treatment. The chronotropic response to a single isoproterenol injection was blunted by doxorubicin, but the inotropic response was maintained in both males and females. Pre-exposure to doxorubicin caused cardiac atrophy in both control and isoproterenol-treated male mice but not in female mice. Counterintuitively, pre-exposure to doxorubicin abrogated isoproterenol-induced cardiac fibrosis. However, there were no sex differences in the expression of markers of pathological hypertrophy, fibrosis, or inflammation. Gonadectomy did not reverse the sexually dimorphic effects of doxorubicin. Additionally, pre-exposure to doxorubicin abrogated the hypertrophic response to isoproterenol in castrated male mice but not in ovariectomized female mice. Therefore, pre-exposure to doxorubicin caused male-specific cardiac atrophy that persisted after isoproterenol treatment, which could not be prevented by gonadectomy.

Psychological measures of stress and biomarkers of inflammation, aging, and endothelial dysfunction in breast cancer survivors on aromatase inhibitors

The use of aromatase inhibitors (AIs) is associated with higher rates of cardiovascular events and lower endothelial function in breast cancer survivors. Psychosocial stress is associated with higher levels of inflammatory and aging markers, and lower endothelial function in otherwise healthy subjects. These associations among breast cancer survivors on AIs are not well defined. A cross-sectional study of 30 breast cancer survivors on AIs was performed to assess the associations between self-reported scores of psychosocial measures of depression, anxiety, and stress assessed by validated questionnaires with markers of inflammation (CRP; IL-6; IL-18), aging (p16^INK4a), and endothelial function (ICAM-1, EndoPAT ratio). Significant positive correlations were observed between psychosocial measures and inflammatory markers including CRP, IL-6, and ICAM-1. However, no psychosocial scores were related to endothelial function or gene expression of the aging biomarker p16INK4a. Overall, survivors had endothelial dysfunction with reduced EndoPAT ratios. Psychosocial stress is associated with greater inflammation in breast cancer survivors on AIs, corroborating previous studies in cancer-free populations. The lack of association between psychosocial stress and either endothelial function or aging biomarkers could be due to the already low endothelial function and accelerated aging in our cohort of breast cancer survivors on AIs, though our small sample size limits conclusions. Further work in a larger and more diverse cohort of patients is needed to further understand the relationships among inflammation, aging and endothelial function in breast cancer survivors.

New Insights into the Understanding of Mechanisms of Radiation-Induced Heart Disease

OPINION STATEMENT

Cancer patients who receive high-dose thoracic radiotherapy may develop radiation-induced heart disease (RIHD). The clinical presentation of RIHD comprises coronary artery atherosclerosis, valvular disease, pericarditis, cardiomyopathy, and conduction defects. These complications have significantly reduced due to the improved radiotherapy techniques. However, such methods still could not avoid heart radiation exposure. Furthermore, people who received relatively low-dose radiation exposures have exhibited significantly elevated RIHD risks in cohort studies of atomic bomb survivors and occupational exposures. The increased potential in exposure to natural and artificial ionizing radiation sources has emphasized the necessity to understand the development of RIHD. The pathological processes of RIHD include endothelial dysfunction, inflammation, fibrosis, and hypertrophy. The underlying mechanisms may involve the changes in oxidative stress, DNA damage response, telomere erosion, mitochondrial dysfunction, epigenetic regulation, circulation factors, protein post-translational modification, and metabolites. This review will discuss the recent advances in the mechanisms of RIHD at cellular and molecular levels.

The protective effects of topiramate and spirulina against doxorubicin-induced cardiotoxicity in rats

Doxorubicin (DOX) is a widely used chemotherapy drug that can cause significant cardiotoxicity, limiting its clinical application. This study aimed to investigate the potential protective effects of topiramate (TPM) and spirulina (SP), either alone or in combination, in preventing DOX-induced cardiotoxicity. Adult Sprague Dawley rats were divided into five groups, including a normal control group and groups receiving DOX alone, DOX with TPM, DOX with SP, or DOX with a combination of TPM and SP. Cardiotoxicity was induced by administering DOX intraperitoneally at a cumulative dose of 16 mg/kg over 4 weeks. TPM and/or SP administration started 1 week before DOX treatment and continued for 35 days. Body weight, serum markers of cardiac damage, oxidative stress and inflammatory parameters were assessed. Histopathological and immunohistochemical examinations were performed on cardiac tissues. Results showed that TPM and SP monotherapy led to significant improvements in serum levels of cardiac markers, decreased oxidative stress, reduced fibrosis-related growth factor levels, increased antioxidant levels, and improved histopathological features. SP demonstrated more prominent effects in comparison to TPM, and the combination of TPM and SP exhibited even more pronounced effects. In conclusion, TPM and SP, either alone or in combination, hold promise as therapeutic interventions for mitigating DOX-induced cardiotoxicity.

Risk of mortality and other adverse outcomes from myocardial infarction in cancer survivors: a meta-analysis

BACKGROUND AND PURPOSE

Myocardial infarction (MI) is an acute cardiovascular disease that can increase prognosis risks such as arrhythmia, heart failure, shock, etc. Studies have found that even well-controlled coexistence of cancer could affect the quality of life in MI patients. However, the prognostic impact of cancer on MI patients is controversial. This meta-analysis aimed to assess the influence of cancer on the risk of future all-cause mortality, cardiovascular mortality, and major adverse cardiovascular and cerebrovascular events (MACCE) in MI patients.

METHODS

The Embase, PubMed, and Cochrane libraries were searched for cohort studies and case-control from inception to May 2022. The quality of the included pieces of literature was assessed using the Newcastle-Ottawa Quality Assessment Scale (NOS). All statistical analyses were performed using Stata statistical software versions 14.0 and 16.0. Sensitivity analysis assessed the robustness of the results, and funnel plots and Egger's tests evaluated the publication bias.

RESULTS

A total of 10 studies were included, covering 7,210,530 participants. Summary analyses show that compared with non-cancer patients, cancer increased the risk of long-term all-cause mortality in MI patients (HR 1.58, 95% CI 1.36-1.84, I² = 94.2%). However, no significant difference was observed in the risk of cardiovascular mortality (HR 1.18, 95% CI 0.91-1.54, I² = 52.4%) or MACCE (HR 1.26, 95% CI 0.94-1.70, I² = 99.2%). In subgroup analysis, cancer was associated with the risk of recurrent MI (HR 1.18, 95% CI 1.03-1.34, I² = 88.8%), and major bleeding (HR 2.01, 95% CI 1.60-2.52, I² = 93.1%), with no significant difference in the risk of stroke (HR 1.11, 95% CI 0.97-1.27, I² = 85.1%).

CONCLUSION

This meta-analysis shows that cancer increases the risk of all-cause mortality, recurrent MI, and major bleeding in MI patients but is not associated with the risk of cardiovascular death. Therefore, comprehensive multidisciplinary management and monitoring of potential future adverse events in MI patients with cancer are needed.

SYSTEMATIC REVIEW REGISTRATION

The meta-analysis was registered in the International Register of Prospective Systematic Reviews (NO. CRD42022332775).

Critical Role of Cathepsin L/V in Regulating Endothelial Cell Senescence

The senescence of vascular endothelial cells (ECs) is characterized as a hallmark of vascular aging, which leads to the initiation, progress, and advancement of cardiovascular diseases. However, the mechanism of the ECs senescence remains elusive. In this study, thoracic aortas were separated from young (8-week-old) and aged (18-month-old) mice. Decreased Ctsl expression and increased vascular remodeling were observed in senescent aorta. H₂O₂ was used to induce human umbilical vein endothelial cells (HUVECs) senescence, as shown by increased SA-β-gal positive cells and upregulated p21 level. CTSV significantly decreased after H₂O₂ treatment, while over-expression of CTSV by adenovirus reduced cellular senescence. RNA sequencing analysis was conducted subsequently, and ALDH1A2 was observed to significantly increased in H₂O₂ group and decreased after over-expression of CTSV. This result was further confirmed by RT-PCR and WB. Moreover, over-expression of CTSV reduced the increase of ERK1/2 and AKT phosphorylation induced by H₂O₂. Additionally, retinoic acid (RA), the major production of ALDH1A2, was added to CTSV over-expressed senescent HUVECs. Administration of RA activated AKT and ERK1/2, induced the expression of p21, and enhanced SA-β-gal positive cells, while not affecting the expression of CTSV and ALDH1A2. These results were further confirmed in doxorubicin (DOX)-induced senescent ECs. In conclude, we have identified that Ctsl/CTSV plays a key role in ECs senescence by regulating ALDH1A2 to activate AKT/ ERK1/2-P21 pathway. Therefore, targeting Ctsl/CTSV may be a potential therapeutic strategy in EC senescence.

Anthracycline-induced cardiotoxicity and senescence

Cancer continues to place a heavy burden on healthcare systems around the world. Although cancer survivorship continues to improve, cardiotoxicity leading to cardiomyopathy and heart failure as a consequence of cancer therapy is rising, and yesterday's cancer survivors are fast becoming today's heart failure patients. Although the mechanisms driving cardiotoxicity are complex, cellular senescence is gaining attention as a major contributor to chemotherapy-induced cardiotoxicity and, therefore, may also represent a novel therapeutic target to prevent this disease. Cellular senescence is a well-recognized response to clinical doses of chemotherapies, including anthracyclines, and is defined by cell cycle exit, phenotypic alterations which include mitochondrial dysfunction, and the expression of the pro-senescent, pro-fibrotic, and pro-inflammatory senescence-associated phenotype. Senescence has an established involvement in promoting myocardial remodeling during aging, and studies have demonstrated that the elimination of senescence can attenuate the pathophysiology of several cardiovascular diseases. Most recently, pharmacology-mediated elimination of senescence, using a class of drugs termed senolytics, has been demonstrated to prevent myocardial dysfunction in preclinical models of chemotherapy-induced cardiotoxicity. In this review, we will discuss the evidence that anthracycline-induced senescence causes the long-term cardiotoxicity of anticancer chemotherapies, consider how the senescent phenotype may promote myocardial dysfunction, and examine the exciting possibility that targeting senescence may prove a therapeutic strategy to prevent or even reverse chemotherapy-induced cardiac dysfunction.

Understanding the Protective Role of Exosomes in Doxorubicin-Induced Cardiotoxicity

Doxorubicin (DOX) is a class of effective chemotherapeutic agents widely used in clinical practice. However, its use has been limited by cardiotoxicity. The mechanism of DOX-induced cardiotoxicity (DIC) is complex, involving oxidative stress, Ca²⁺ overload, inflammation, pyroptosis, ferroptosis, apoptosis, senescence, etc. Exosomes (EXOs), as extracellular vesicles (EVs), play an important role in the material exchange and signal transmission between cells by carrying components such as proteins and RNAs. More recently, there has been a growing number of publications focusing on the protective effect of EXOs on DIC. Here, this review summarized the main mechanisms of DIC, discussed the mechanism of EXOs in the treatment of DIC, and further explored the value of EXOs as diagnostic biomarkers and therapeutic strategies for DIC.

EA.hy926 Cells and HUVECs Share Similar Senescence Phenotypes but Respond Differently to the Senolytic Drug ABT-263

Doxorubicin (DOX) induces endothelial cell (EC) senescence, which contributes to endothelial dysfunction and cardiovascular complications. Senolytic drugs selectively eliminate senescent cells to ameliorate senescence-mediated pathologies. Previous studies have demonstrated differences between immortalized and primary EC models in some characteristics. However, the response of DOX-induced senescent ECs to senolytics has not been determined across these two models. In the present work, we first established a comparative characterization of DOX-induced senescence phenotypes in immortalized EA.hy926 endothelial-derived cells and primary human umbilical vein EC (HUVECs). Thereafter, we evaluated the senolytic activity of four senolytics across both ECs. Following the DOX treatment, both EA.hy926 and HUVECs shared similar senescence phenotypes characterized by upregulated senescence markers, increased SA-β-gal activity, cell cycle arrest, and elevated expression of the senescence-associated secretory phenotype (SASP). The potentially senolytic drugs dasatinib, quercetin, and fisetin demonstrated a lack of selectivity against DOX-induced senescent EA.hy926 cells and HUVECs. However, ABT-263 (Navitoclax) selectively induced the apoptosis of DOX-induced senescent HUVECs but not EA.hy926 cells. Mechanistically, DOX-treated EA.hy926 cells and HUVECs demonstrated differential expression levels of the BCL-2 family proteins. In conclusion, both EA.hy926 cells and HUVECs demonstrate similar DOX-induced senescence phenotypes but they respond differently to ABT-263, presumably due to the different expression levels of BCL-2 family proteins.

Late onset cardiovascular dysfunction in adult mice resulting from galactic cosmic ray exposure

The complex and inaccessible space radiation environment poses an unresolved risk to astronaut cardiovascular health during long-term space exploration missions. To model this risk, healthy male c57BL/6 mice aged six months (corresponding to an astronaut of 34 years) were exposed to simplified galactic cosmic ray (GCR5-ion; 5-ion sim) irradiation at the NASA Space Radiation Laboratory (NSRL) at Brookhaven National Laboratories (BNL). Multi-modal cardiovascular functional assessments performed longitudinally and terminally revealed significant impairment in cardiac function in mice exposed to GCR5-ion compared to unirradiated controls, gamma irradiation, or single mono-energetic ions (56Fe or 16O). GCR5-ion-treated mice exhibited increased arterial elastance likely mediated by disruption of elastin fibers. This study suggests that a single exposure to GCR5-ion is associated with deterioration in cardiac structure and function that becomes apparent long after exposure, likely associated with increased morbidity and mortality. These findings represent important health considerations when preparing for successful space exploration.

Molecular biomarkers in cardio-oncology: Where we stand and where we are heading

Until recently, cardiotoxicity in the setting of a malignant disease was attributed solely to the detrimental effects of chemo- and/or radio-therapy to the heart. On this account, the focus was on the evaluation of well-established cardiac biomarkers for the early detection of myocardial damage. Currently, this view has been revised. Cardiotoxicity is not restricted to a single organ but instead affects the endothelium as a whole. Indeed, it has come into light that not only cancer therapy but also malignant cells per se can impair the cardiovascular system, through a paracrine and endocrine mode of action. Even more intriguingly, a clear interplay between molecular pathways involved in cancer and cardiovascular disease has become prevalent, suggesting a common nominator that governs the pathophysiology of these two entities. Taken together, our strategy in the quest of novel biomarkers in the emerging field of cardio-oncology should be critically reshaped.

The interplay between apoptosis and cellular senescence: Bcl-2 family proteins as targets for cancer therapy

Cell death by apoptosis and permanent cell cycle arrest by senescence serve as barriers to the development of cancer. Chemotherapeutic agents not only induce apoptosis, they can also induce senescence known as therapy-induced senescence (TIS). There are, however, controversies whether TIS improves or worsens therapeutic outcome. Unlike apoptosis, which permanently removes cancer cells, senescent cells are metabolically active, and can contribute to tumor progression and relapse. If senescent cells are not cleared by the immune system or if cancer cells escape senescence, they may acquire resistance to apoptotic stimuli and become highly aggressive. Thus, there have been significant efforts in developing senolytics, drugs that target these pro-survival molecules to eliminate senescent cells. The anti-apoptotic Bcl-2 family proteins not only protect against cell death by apoptosis, but they also allow senescent cells to survive. While combining senolytics with chemotherapeutic drugs is an attractive approach, there are also limitations. Moreover, members of the Bcl-2 family have distinct effects on apoptosis and senescence. The purpose of this review article is to discuss recent literatures on how members of the Bcl-2 family orchestrate the interplay between apoptosis and senescence, and the challenges and progress in targeting these Bcl-2 family proteins for cancer therapy.

The Interplay Between Autophagy and Senescence in Anthracycline Cardiotoxicity

PURPOSE OF REVIEW

Doxorubicin (DOXO) is a highly effective chemotherapeutic drug employed for the treatment of a wide spectrum of cancers, spanning from solid tumours to haematopoietic malignancies. However, its clinical use is hampered by severe and dose-dependent cardiac side effects that ultimately lead to heart failure (HF).

RECENT FINDINGS

Mitochondrial dysfunction and oxidative stress are well-established mechanisms of DOXO-induced cardiotoxicity, although recent evidence suggests that deregulation of other biological processes, like autophagy, could be involved. It is increasingly recognized that autophagy deregulation is intimately interconnected with the initiation of detrimental cellular responses, including autosis and senescence, raising the possibility of using autophagy modulators as well as senolytics and senomorphics for preventing DOXO cardiotoxicity. This review aims at providing an overview of the signalling pathways that are common to autophagy and senescence, with a special focus on how the relationship between these two processes is deregulated in response to cardiotoxic treatments. Finally, we will discuss the potential therapeutic utility of drugs modulating autophagy and/or senescence for counteracting DOXO cardiotoxicity.

Radiation-Induced Senescence Reprograms Secretory and Metabolic Pathways in Colon Cancer HCT-116 Cells

Understanding the global metabolic changes during the senescence of tumor cells can have implications for developing effective anti-cancer treatment strategies. Ionizing radiation (IR) was used to induce senescence in a human colon cancer cell line HCT-116 to examine secretome and metabolome profiles. Control proliferating and senescent cancer cells (SCC) exhibited distinct morphological differences and expression of senescent markers. Enhanced secretion of pro-inflammatory chemokines and IL-1, anti-inflammatory IL-27, and TGF-β1 was observed in SCC. Significantly reduced levels of VEGF-A indicated anti-angiogenic activities of SCC. Elevated levels of tissue inhibitors of matrix metalloproteinases from SCC support the maintenance of the extracellular matrix. Adenylate and guanylate energy charge levels and redox components NAD and NADP and glutathione were maintained at near optimal levels indicating the viability of SCC. Significant accumulation of pyruvate, lactate, and suppression of the TCA cycle in SCC indicated aerobic glycolysis as the predominant energy source for SCC. Levels of several key amino acids decreased significantly, suggesting augmented utilization for protein synthesis and for use as intermediates for energy metabolism in SCC. These observations may provide a better understanding of cellular senescence basic mechanisms in tumor tissues and provide opportunities to improve cancer treatment.