Oncogene-induced cell senescence--halting on the road to cancer

A non-canonical role for a small nucleolar RNA in ribosome biogenesis and senescence

Cellular senescence is an irreversible state of cell-cycle arrest induced by various stresses, including aberrant oncogene activation, telomere shortening, and DNA damage. Through a genome-wide screen, we discovered a conserved small nucleolar RNA (snoRNA), SNORA13, that is required for multiple forms of senescence in human cells and mice. Although SNORA13 guides the pseudouridylation of a conserved nucleotide in the ribosomal decoding center, loss of this snoRNA minimally impacts translation. Instead, we found that SNORA13 negatively regulates ribosome biogenesis. Senescence-inducing stress perturbs ribosome biogenesis, resulting in the accumulation of free ribosomal proteins (RPs) that trigger p53 activation. SNORA13 interacts directly with RPL23, decreasing its incorporation into maturing 60S subunits and, consequently, increasing the pool of free RPs, thereby promoting p53-mediated senescence. Thus, SNORA13 regulates ribosome biogenesis and the p53 pathway through a non-canonical mechanism distinct from its role in guiding RNA modification. These findings expand our understanding of snoRNA functions and their roles in cellular signaling.

Review: Are moles senescent?

Melanocytic nevi (skin moles) have been regarded as a valuable example of cell senescence occurring in vivo. However, a study of induced nevi in a mouse model reported that the nevi were arrested by cell interactions rather than a cell-autonomous process like senescence, and that size distributions of cell nests within nevi could not be accounted for by a stochastic model of oncogene-induced senescence. Moreover, others reported that some molecular markers used to identify cell senescence in human nevi are also found in melanoma cells-not senescent. It has thus been questioned whether nevi really are senescent, with potential implications for melanoma diagnosis and therapy. Here I review these areas, along with the genetic, biological, and molecular evidence supporting senescence in nevi. In conclusion, there is strong evidence that cells of acquired human benign (banal) nevi are very largely senescent, though some must contain a minor non-senescent cell subpopulation. There is also persuasive evidence that this senescence is primarily induced by dysfunctional telomeres rather than directly oncogene-induced.

Gender-specific associations between mixture of polycyclic aromatic hydrocarbons and telomere length

Evidence shows the relationships of individual environmental PAHs by their urinary metabolites with relative telomere length (RTL), which may be affected by biological gender differences. Since plasma parent PAHs are not metabolized, it may reflect human exposure to PAHs more realistically in daily life. Thus, exploring joint associations between plasma parent PAHs and RTL is urgent, which may identify the major contributor to its adverse effect. In this study, 2577 participants were obtained from the Henan Rural Cohort. The level of PAHs in blood samples was detected by gas chromatography coupled with tandem mass spectrometry. RTL in blood samples was detected by quantitative polymerase chain reaction. Generalized linear models or quantile g-computation were performed to evaluate the associations between the individual or a mixture of PAHs and RTL. Results from generalized linear models showed that each unit increment in BghiP value corresponded to a 0.098 (95%CI: 0.067, 0.129) increment in RTL for men; each unit increment in BaP, BghiP and Flu value corresponded to a 0.041 (95%CI: 0.014, 0.068), 0.081 (95%CI: 0.055, 0.107) and 0.016 (95%CI: 0.005, 0.027) increment in RTL for women. Results from quantile-g computation revealed that each one-quantile increment in the mixture of 10 PAHs corresponded to a 0.057 (95%CI: 0.021, 0.094) and 0.047 (95%CI: 0.003, 0.091) increment in RTL values of women and men, but these associations were mainly ascribed to three PAHs for women (BaP, Flu and BghiP) and men (BaP, BghiP and Pyr), respectively. Similar results were found in smoking men and cooking women without smoking. Our study found that exposure to 10 PAHs mixture was positively associated with RTL across gender, mainly attributed to Flu, BaP and BghiP, implicating that gender-specific associations may be ascribed to tobacco and cooking smoke pollution. The findings provided clues for effective measures to control PAHs pollutants-related aging disease.Clinical trial registration The Henan Rural Cohort Study has been registered at the Chinese Clinical Trial Register (Registration number: ChiCTR-OOC-15006699). Date of registration: 06 July 2015. http://www.chictr.org.cn/showproj.aspx?proj=11375 .

Association of telomere length with risk of lung cancer: A large prospective cohort study from the UK Biobank

OBJECTIVES

Leukocyte telomere length (LTL) is associated with a wide variety of diseases, including cancer. However, findings regarding the association between LTL and the risk for lung cancer have been inconclusive and inconsistent across previous observational studies.

METHODS

This prospective cohort study included data from 425,146 participants 37-73 years of age housed in the UK Biobank. Quantitative polymerase chain reaction (qPCR) was used to measure LTL in baseline DNA samples. A multivariate Cox proportional hazards model was used to evaluate the relationship between LTL and the risk for lung cancer.

RESULTS

An increase in LTL per interquartile range (IQR) was associated with a 9% increase in the risk for lung cancer (hazard ratio [HR] 1.09 [95% confidence interval (CI) 1.03-1.16]). Participants in the highest LTL quintile exhibited an approximately 25% elevated risk for developing lung cancer (HR 1.25 [95% CI 1.09-1.45]) compared with those in the lowest quintile. The relationship between per IQR increase in LTL and elevated risk for lung cancer was greater in the histological subtype of adenocarcinoma (HR 1.30 [95% CI 1.18-1.43]), female sex (HR 1.16 [95% CI 1.06-1.26]), non-smokers (HR 1.45 [95% CI 1.23-1.71]), and individuals with high genetic risk for lung cancer (HR 1.18 [95% CI 1.03-1.34]), respectively. Surprisingly, a per IQR increase in LTL was associated with increased risks for both lung adenocarcinoma (HR 1.56 [95% CI 1.24-1.96]) and squamous cell carcinoma (HR 2.01 [95% CI 1.13-3.56]) in never smokers.

CONCLUSIONS

Longer LTL was associated with an elevated risk for lung cancer, particularly for adenocarcinoma and squamous cell carcinoma in never smokers. The results suggest the potential of telomeres as non-invasive biomarkers for the early screening of lung cancer, particularly in non-smokers, who are typically overlooked.

Understanding NK cell biology for harnessing NK cell therapies: targeting cancer and beyond

Gene-engineered immune cell therapies have partially transformed cancer treatment, as exemplified by the use of chimeric antigen receptor (CAR)-T cells in certain hematologic malignancies. However, there are several limitations that need to be addressed to target more cancer types. Natural killer (NK) cells are a type of innate immune cells that represent a unique biology in cancer immune surveillance. In particular, NK cells obtained from heathy donors can serve as a source for genetically engineered immune cell therapies. Therefore, NK-based therapies, including NK cells, CAR-NK cells, and antibodies that induce antibody-dependent cellular cytotoxicity of NK cells, have emerged. With recent advances in genetic engineering and cell biology techniques, NK cell-based therapies have become promising approaches for a wide range of cancers, viral infections, and senescence. This review provides a brief overview of NK cell characteristics and summarizes diseases that could benefit from NK-based therapies. In addition, we discuss recent preclinical and clinical investigations on the use of adoptive NK cell transfer and agents that can modulate NK cell activity.

Gene set variation analysis-based aging and senescence score as a prognostic indicator and therapeutic guide in lung adenocarcinoma

Accumulating evidence suggests that aging and senescence play crucial roles in tumorigenesis, cancer progression, and treatment. However, the influence of aging and senescence-related genes (ASRGs) on clinical outcomes and treatment options in lung adenocarcinoma (LUAD) patients remains unknown. Here, we developed an aging and senescence-related scoring system, ASRS, by integrating bulk transcriptome data from 22 LUAD datasets. In 3,243 LUAD samples, higher ASRS scores were associated with poor tumor stage and pathological grade, as well as shorter overall survival, disease-free survival, and recurrence-free survival. Additionally, ASRS was associated with different immune patterns in the tumor microenvironment (TME). Importantly, ASRS was found to predict therapeutic efficacy, with patients having a low ASRS benefiting from immunotherapy and those with a high ASRS responding better to chemotherapy. Therefore, ASRS represents a previously overlooked characteristic of LUAD that can influence patient outcomes and treatment success.

Diagnostic Scrutiny and Patterns of Elevated Cancer Risk: Uncovering Overdiagnosis Through Standardized Incidence Ratios

Certain medical diagnoses and environmental or occupational exposures may be associated with elevated risk of cancer diagnosis, either through causal mechanisms or via increased detection of a subclinical reservoir through increased diagnostic scrutiny (overdiagnosis). The present study aimed to investigate the distribution of elevated cancer risks associated with different diagnoses and exposures. A systematic literature search was conducted to identify studies published in the last 30 years that examined the standardized incidence ratio (SIR) associated with exposures and risk factors. Meta-SIRs for each cancer type were calculated. The distribution of elevated cancer risks was then compared between cancer types previously reported to be susceptible to overdiagnosis and those that have not been associated with overdiagnosis. The review of 108 studies identified four patterns: SIR generally elevated for 1) only overdiagnosis-susceptible cancer types, 2) both overdiagnosed and non-overdiagnosed cancer types, 3) select cancers in accordance with risk factor or exposure, and 4) SIRs that did not exhibit a distinct increase in any cancer type. The distribution of elevated cancer risks may serve as a signature of whether the underlying risk factor or exposure is a carcinogenic process or a mechanism of increased diagnostic scrutiny uncovering clinically occult diseases. The identification of increased cancer risk should be viewed with caution, and analyzing the pattern of elevated cancer risk distribution can potentially reveal conditions that appear to be cancer risk factors but are in fact the result of exposure to medical surveillance or other healthcare activities that lead to the detection of indolent tumors.

Molecular Mobility of Polyrotaxane Surfaces Alleviates Oxidative Stress-Induced Senescence in Mesenchymal Stem Cells

Polyrotaxane is a supramolecular assembly consisting of multiple cyclic molecules threaded by a linear polymer. One of the unique properties of polyrotaxane is molecular mobility, cyclic molecules moving along the linear polymer. Molecular mobility of polyrotaxane surfaces affects cell spreading, differentiation, and other cell-related aspects through changing subcellular localization of yes-associated proteins (YAPs). Subcellular YAP localization is also related to cell senescence derived from oxidative stress, which is known to cause cancer, diabetes, and heart disease. Herein, the effects of polyrotaxane surface molecular mobility on subcellular YAP localization and cell senescence following H2 O2 -induced oxidative stress are evaluated in human mesenchymal stem cells (HMSCs) cultured on polyrotaxane surfaces with different molecular mobilities. Oxidative stress promotes cytoplasmic YAP localization in HMSCs on high-mobility polyrotaxane surfaces; however, low-mobility polyrotaxane surfaces more effectively maintain nuclear YAP localization, exhibiting lower senescence-associated β-galactosidase activity and senescence-related gene expression and DNA damage than that seen with the high-mobility surfaces. These results suggest that the molecular mobility of polyrotaxane surfaces regulates subcellular YAP localization, thereby protecting HMSCs from oxidative stress-induced cell senescence. Applying the molecular mobility of polyrotaxane surfaces to implantable scaffolds can provide insights into the prevention and treatment of diseases caused by oxidative stress.

The hallmarks of cancer… in pituitary tumors?

Over 20 years ago, Hanahan and Weinberg published a seminal review that addressed the biological processes that underly malignant transformation. This classical review, along with two revisions published in 2011 and 2022, has remain a classic of the oncology literature. Since many of the addressed biological processes may apply to non-malignant tumorigenesis, we evaluated to what extent these hallmarks pertain to the development of pituitary adenomas.Some of the biological processes analyzed in this review include genome instability generated by somatic USP8 and GNAS mutations in Cushing's diseases and acromegaly respectively; non-mutational epigenetic reprograming through changes in methylation; induction of angiogenesis through alterations of VEGF gene expression; promotion of proliferative signals mediated by EGFR; evasion of growth suppression by disrupting cyclin dependent kinase inhibitors; avoidance of immune destruction; and the promotion of inflammation mediated by alteration of gene expression of immune check points. We also elaborate further on the existence of oncogene induced senescence in pituitary tumors. We conclude that a better understanding of these processes can help us dilucidated why pituitary tumors are so resistant to malignant transformation and can potentially contribute to the development of novel anticancer treatments.

Multi-range ERK responses shape the proliferative trajectory of single cells following oncogene induction

Oncogene-induced senescence is a phenomenon in which aberrant oncogene expression causes non-transformed cells to enter a non-proliferative state. Cells undergoing oncogenic induction display phenotypic heterogeneity, with some cells senescing and others remaining proliferative. The causes of heterogeneity remain unclear. We studied the sources of heterogeneity in the responses of human epithelial cells to oncogenic BRAF^V600E expression. We found that a narrow expression range of BRAF^V600E generated a wide range of activities of its downstream effector ERK. In population-level and single-cell assays, ERK activity displayed a non-monotonic relationship to proliferation, with intermediate ERK activities leading to maximal proliferation. We profiled gene expression across a range of ERK activities over time and characterized four distinct ERK response classes, which we propose act in concert to generate the ERK-proliferation response. Altogether, our studies map the input-output relationships between ERK activity and proliferation, elucidating how heterogeneity can be generated during oncogene induction.

Women's experiences of age-related discontinuation from mammography screening: A qualitative interview study

INTRODUCTION

In Denmark, women are discontinued from mammography screening at age 69 due to decreased likelihood of benefits and increased likelihood of harm. The risk of harm increases with age and includes false positives, overdiagnosis and overtreatment. In a questionnaire survey, 24 women expressed unsolicited concerns about being discontinued from mammography screening due to age. This calls for further investigation of experiences related to discontinuation from screening.

METHODS

We invited the women, who had left comments on the questionnaire, to participate in in-depth interviews with the purpose to explore their reactions, preferences, and conceptions about mammography screening and discontinuation. The interviews lasted 1-4 h and were followed up with a telephone interview 2 weeks after the initial interview.

RESULTS

The women had high expectations of the benefits of mammography screening and felt that participation was a moral obligation. Following that, they perceived the screening discontinuation as a result of societal age discrimination and consequently felt devalued. Further, the women perceived the discontinuation as a health threat, felt more susceptible to late diagnosis and death, and therefore sought out new ways to control their risk of breast cancer.

CONCLUSION

Our findings indicate that the age-related discontinuation from mammography screening might be of more importance than previously assumed. This study raises important questions about screening ethics, and we encourage research to explore this in other settings.

PATIENT AND PUBLIC CONTRIBUTION

This study was conducted as a result of the women's unsolicited concerns about being discontinued from screening. This particular group contributed to the study with their own statements, interpretations and perspectives on the discontinuation of screening, and the initial analysis of data was discussed with the women during follow-up interviews.

Targeting anti-apoptotic pathways eliminates senescent melanocytes and leads to nevi regression

Human melanocytic nevi (moles) result from a brief period of clonal expansion of melanocytes. As a cellular defensive mechanism against oncogene-induced hyperplasia, nevus-resident melanocytes enter a senescent state of stable cell cycle arrest. Senescent melanocytes can persist for months in mice and years in humans with a risk to escape the senescent state and progress to melanoma. The mechanisms providing prolonged survival of senescent melanocytes remain poorly understood. Here, we show that senescent melanocytes in culture and in nevi express high level of the anti-apoptotic BCL-2 family member BCL-W but remain insensitive to the pan-BCL-2 inhibitor ABT-263. We demonstrate that resistance to ABT-263 is driven by mTOR-mediated enhanced translation of another anti-apoptotic member, MCL-1. Strikingly, the combination of ABT-263 and MCL-1 inhibitors results in synthetic lethality to senescent melanocytes, and its topical application sufficient to eliminate nevi in male mice. These data highlight the important role of redundant anti-apoptotic mechanisms for the survival advantage of senescent melanocytes, and the proof-of-concept for a non-invasive combination therapy for nevi removal.

Immune senescence in non-small cell lung cancer management: therapeutic relevance, biomarkers, and mitigating approaches

INTRODUCTION

Lung cancer and mainly non-small cell lung cancer (NSCLC) still remain a prevalent malignancy worldwide despite sustained screening approaches. Furthermore, a significant proportion of the cases are diagnosed at advanced stages when conservative therapy is often unsuccessful. Cell senescence is an endogenous antitumor weapon but when it is upregulated exerts opposite activities favoring tumor metastasizing and poor response to therapy. However, little is known about this dangerous relationship between cell senescence and NSCLC outcome or on potential approaches to mitigate its unfavorable consequences.

AREAS COVERED

We discuss cell senescence focusing on immune senescence, its cell and humoral effectors (namely immune senescence associated secretory phenotype-iSASP), its impact on NSCLC outcome, and its biomarkers. Senotherapeutics as mitigating approaches are also considered based on the availability of experimental data pertinent to NSCLC.

EXPERT OPINION

Characterization of NSCLC subsets in which immune senescence is a risk factor for poor prognosis and poor therapeutic response might be very helpful in supporting the addition of senotherapeutics to conventional cancer therapy. This approach has the potential to improve disease outcome but more studies in this area are necessary.

Giant Multinucleated Cells in Aging and Senescence-An Abridgement

Simple Summary

Aging is a progressive decline of an organism over time. In contrast, senescence occurs throughout an organism’s lifespan. It is a cell-cycle arrest preventing the proliferation of damaged cells. Cellular and molecular senescence timing is crucial for the pace of aging and disease development and progression. The accumulation of senescent cells during a lifespan leads to organismal senescence. Senescent multinucleated giant cells are present in many age-related diseases and cancer. Although senescence was assumed to be irreversible, studies now show that senescent multinucleated giant cells overcome senescence in various cancers, becoming the source of highly aggressive mononucleated stem-like cells, which divide and initiate tumor development and progression.

Abstract

This review introduces the subject of senescence, aging, and the formation of senescent multinucleated giant cells. We define senescence and aging and describe how molecular and cellular senescence leads to organismal senescence. We review the latest information on senescent cells’ cellular and molecular phenotypes. We describe molecular and cellular features of aging and senescence and the role of multinucleated giant cells in aging-related conditions and cancer. We explain how multinucleated giant cells form and their role in aging arteries and gonads. We also describe how multinucleated giant cells and the reversibility of senescence initiate cancer and lead to cancer progression and metastasis. We also describe molecules and pathways regulating aging and senescence in model systems and their applicability to clinical therapies in age-related diseases.

Focus on the Contribution of Oxidative Stress in Skin Aging

Skin aging is one of the most evident signs of human aging. Modification of the skin during the life span is characterized by fine lines and wrinkling, loss of elasticity and volume, laxity, rough-textured appearance, and pallor. In contrast, photoaged skin is associated with uneven pigmentation (age spot) and is markedly wrinkled. At the cellular and molecular level, it consists of multiple interconnected processes based on biochemical reactions, genetic programs, and occurrence of external stimulation. The principal cellular perturbation in the skin driving senescence is the alteration of oxidative balance. In chronological aging, reactive oxygen species (ROS) are produced mainly through cellular oxidative metabolism during adenosine triphosphate (ATP) generation from glucose and mitochondrial dysfunction, whereas in extrinsic aging, loss of redox equilibrium is caused by environmental factors, such as ultraviolet radiation, pollution, cigarette smoking, and inadequate nutrition. During the aging process, oxidative stress is attributed to both augmented ROS production and reduced levels of enzymatic and non-enzymatic protectors. Apart from the evident appearance of structural change, throughout aging, the skin gradually loses its natural functional characteristics and regenerative potential. With aging, the skin immune system also undergoes functional senescence manifested as a reduced ability to counteract infections and augmented frequency of autoimmune and neoplastic diseases. This review proposes an update on the role of oxidative stress in the appearance of the clinical manifestation of skin aging, as well as of the molecular mechanisms that underline this natural phenomenon sometimes accelerated by external factors.

Cellular senescence in neuroblastoma

Neuroblastoma is a tumour that arises from the sympathoadrenal lineage occurring predominantly in children younger than five years. About half of the patients are diagnosed with high-risk tumours and undergo intensive multi-modal therapy. The success rate of current treatments for high-risk neuroblastoma is disappointingly low and survivors suffer from multiple therapy-related long-term side effects. Most chemotherapeutics drive cancer cells towards cell death or senescence. Senescence has long been considered to represent a terminal non-proliferative state and therefore an effective barrier against tumorigenesis. This dogma, however, has been challenged by recent observations that infer a much more dynamic and reversible nature for this process, which may have implications for the efficacy of therapy-induced senescence-oriented treatment strategies. Neuroblastoma cells in a dormant, senescent-like state may escape therapy, whilst their senescence-associated secretome may promote inflammation and invasiveness, potentially fostering relapse. Conversely, due to its distinct molecular identity, senescence may also represent an opportunity for the development of novel (combination) therapies. However, the limited knowledge on the molecular dynamics and diversity of senescence signatures demands appropriate models to study this process in detail. This review summarises the molecular knowledge about cellular senescence in neuroblastoma and investigates current and future options towards therapeutic exploration.

Psoralidin, a natural compound from Psoralea corylifolia, induces oxidative damage mediated apoptosis in colon cancer cells

Psoralidin (PSO) is a natural coumarin isolated from the seeds of Psoralea corylifolia Linn. Previous studies have reported that PSO exerts numerous pharmacological bioactivities including antitumor. The present study aimed to investigate its anticancer effect using colon cancer cells. Cultured HT-29 and HCT-116 colon cancer cells were treated with different concentrations of PSO, and the cell viability, the intracellular reactive oxygen species (ROS), the protein expression, and the apoptosis were determined by MTT assay, DCFH₂ -DA fluorescence probe, Western blotting, and Annexin V/7-AAD staining, respectively. The activities of caspase 3/7 were determined by a commercial kit. Our study found that PSO effectively induces apoptotic cell death mediated by caspase 3/7 in HT-29 and HCT-116 colon cancer cells. PSO treatment rapidly boosts the ROS generation, which is responsible for the PSO-triggered DNA damage, mitochondria membrane potential decrease and caspase 3/7 activation, and c-Jun N-terminal kinase 1/2 activation. Collectively, these results showed that PSO triggered oxidative damage mediated apoptosis in colon cancer cells.

The Molecular Pathology of Odontogenic Tumors: Expanding the Spectrum of MAPK Pathway Driven Tumors

Odontogenic tumors comprise a heterogeneous group of lesions that arise from the odontogenic apparatus and their remnants. Although the etiopathogenesis of most odontogenic tumors remains unclear, there have been some advances, recently, in the understanding of the genetic basis of specific odontogenic tumors. The mitogen-activated protein kinases/extracellular signal-regulated kinases (MAPK/ERK) pathway is intimately involved in the regulation of important cellular functions, and it is commonly deregulated in several human neoplasms. Molecular analysis performed by different techniques, including direct sequencing, next-generation sequencing, and allele-specific qPCR, have uncovered mutations in genes related to the oncogenic MAPK/ERK signaling pathway in odontogenic tumors. Genetic mutations in this pathway genes have been reported in epithelial and mixed odontogenic tumors, in addition to odontogenic carcinomas and sarcomas. Notably, B-Raf proto-oncogene serine/threonine kinase (BRAF) and KRAS proto-oncogene GTPase (KRAS) pathogenic mutations have been reported in a high proportion of ameloblastomas and adenomatoid odontogenic tumors, respectively. In line with the reports about other neoplasms that harbor a malignant counterpart, the frequency of BRAF p.V600E mutation is higher in ameloblastoma (64% in conventional, 81% in unicystic, and 63% in peripheral) than in ameloblastic carcinoma (35%). The objective of this study was to review MAPK/ERK genetic mutations in benign and malignant odontogenic tumors. Additionally, such genetic alterations were discussed in the context of tumorigenesis, clinical behavior, classification, and future perspectives regarding therapeutic approaches.

Cellular Senescence: Mechanisms and Therapeutic Potential

Cellular senescence is a complex and multistep biological process which cells can undergo in response to different stresses. Referring to a highly stable cell cycle arrest, cellular senescence can influence a multitude of biological processes-both physiologically and pathologically. While phenotypically diverse, characteristics of senescence include the expression of the senescence-associated secretory phenotype, cell cycle arrest factors, senescence-associated β-galactosidase, morphogenesis, and chromatin remodelling. Persistent senescence is associated with pathologies such as aging, while transient senescence is associated with beneficial programmes, such as limb patterning. With these implications, senescence-based translational studies, namely senotherapy and pro-senescence therapy, are well underway to find the cure to complicated diseases such as cancer and atherosclerosis. Being a subject of major interest only in the recent decades, much remains to be studied, such as regarding the identification of unique biomarkers of senescent cells. This review attempts to provide a comprehensive understanding of the diverse literature on senescence, and discuss the knowledge we have on senescence thus far.

NR4A1 regulates expression of immediate early genes, suppressing replication stress in cancer

Deregulation of oncogenic signals in cancer triggers replication stress. Immediate early genes (IEGs) are rapidly and transiently expressed following stressful signals, contributing to an integrated response. Here, we find that the orphan nuclear receptor NR4A1 localizes across the gene body and 3' UTR of IEGs, where it inhibits transcriptional elongation by RNA Pol II, generating R-loops and accessible chromatin domains. Acute replication stress causes immediate dissociation of NR4A1 and a burst of transcriptionally poised IEG expression. Ectopic expression of NR4A1 enhances tumorigenesis by breast cancer cells, while its deletion leads to massive chromosomal instability and proliferative failure, driven by deregulated expression of its IEG target, FOS. Approximately half of breast and other primary cancers exhibit accessible chromatin domains at IEG gene bodies, consistent with this stress-regulatory pathway. Cancers that have retained this mechanism in adapting to oncogenic replication stress may be dependent on NR4A1 for their proliferation.

Potential Use of Senolytics for Pharmacological Targeting of Precancerous Lesions

Senescence is a cell state that contributes to several homeostatic and pathologic processes. In addition to being induced in somatic cells in response to replicative exhaustion (replicative senescence) as part of organismal aging, senescence can also be triggered prematurely by oncogene hyperactivation or tumor suppressor dysfunction [oncogene-induced senescence (OIS)]. Consequently, senescent cells comprise a major component of precancerous lesions of skin, oral mucosa, nasopharynx, prostate, gut, and lung. Unfortunately, invasive (or minimally invasive) interventions are currently the only available approach employed to eradicate premalignant lesions that carry the potential for cancer progression. Senolytics are a newly emerging drug class capable of selectively eliminating senescent cells. Although senolytics have been successfully demonstrated to mitigate a myriad of aging-related pathologies and to cull senescent cancer cells, there is a paucity of evidence for the potential use of senolytics as a novel approach to eliminate oncogene-induced senescent cells. This Emerging Concepts commentary will 1) summarize evidence in established models of OIS including B-Raf-induced nevi, transgenic lung cancer, and pancreatic adenocarcinoma models, as well as evidence from clinical precancerous lesions; 2) suggest that OIS is targetable; and 3) propose the utilization of senolytic agents as a revolutionary means to interfere with the ability of senescent premalignant cells to progress to cancer in vitro and in vivo If proven to be effective, senolytics will represent an emerging tool to pharmacologically treat precancerous lesions. SIGNIFICANCE STATEMENT: The treatment of premalignant lesions is largely based on the utilization of invasive (or minimally invasive) measures. Oncogene-induced senescence (OIS) is one form of senescence that occurs in response to oncogene overexpression in somatic cells and is present in precancerous lesions. Although the contribution of OIS to disease progression is undetermined, recent evidence suggests that senescent cells are permissive for malignant transformation. Accordingly, the pharmacological targeting of oncogene-induced senescent cells could potentially provide a novel, less invasive, means for the treatment of premalignant disease.

Involvement of c-Myc in low dose radiation-induced senescence enhanced migration and invasion of unirradiated cancer cells

Ionizing radiation is known to cause cell apoptosis at high dose range, but little is known about the cellular response to low dose radiation. In this study, we found that conditioned medium harvested from WI-38 lung fibroblasts and H1299 lung adenocarcinoma cells exposed to 0.1Gy to 1Gy could enhance the migration and invasion of unirradiated H1299 cells in both 2D and 3D culturing circumstances. Low dose radiation did not induce apoptosis, but induced senescence in irradiated cells. We next examined the expression of immediately early genes including c-Myc and K-Ras. Although both genes could be up-regulated by low dose radiation, induction of c-Myc was more specific to low dose range (0.5Gy) at transcriptional and translational levels. Knockdown of c-Myc by shRNA could repress the senescence induced by low dose radiation. The conditioned medium of irradiated cells induced migration of unirradiated cells was also repressed by knockdown of c-Myc. The c-Myc inhibitor 10058-F4 could suppress low dose radiation induced cell senescence, and the conditioned medium harvested from irradiated cells pretreated with 10058-F4 also lost the ability to enhance the migration of unirradiated cells. The cytokine array analysis revealed that immunosuppressive monocyte chemoattractant protein-1 increased by low dose radiation could be repressed by 10058-F4. We also showed that 10058-F4 could suppress low dose radiation induced tumor progression in a xenograft tumor model. Taken together, current data suggest that -Myc is involved in low dose radiation induced cell senescence and potent bystander effect to increase the motility of unirradiated cells.

Senescence-Induced Chemoresistance in Triple Negative Breast Cancer and Evolution-Based Treatment Strategies

Triple negative breast cancer (TNBC) is classically treated with combination chemotherapies. Although, initially responsive to chemotherapies, TNBC patients frequently develop drug-resistant, metastatic disease. Chemotherapy resistance can develop through many mechanisms, including induction of a transient growth-arrested state, known as the therapy-induced senescence (TIS). In this paper, we will focus on chemoresistance in TNBC due to TIS. One of the key characteristics of senescent cells is a complex secretory phenotype, known as the senescence-associated secretory proteome (SASP), which by prompting immune-mediated clearance of senescent cells maintains tissue homeostasis and suppresses tumorigenesis. However, in cancer, particularly with TIS, senescent cells themselves as well as SASP promote cellular reprograming into a stem-like state responsible for the emergence of drug-resistant, aggressive clones. In addition to chemotherapies, outcomes of recently approved immune and DNA damage-response (DDR)-directed therapies are also affected by TIS, implying that this a common strategy used by cancer cells for evading treatment. Although there has been an explosion of scientific research for manipulating TIS for prevention of drug resistance, much of it is still at the pre-clinical stage. From an evolutionary perspective, cancer is driven by natural selection, wherein the fittest tumor cells survive and proliferate while the tumor microenvironment influences tumor cell fitness. As TIS seems to be preferred for increasing the fitness of drug-challenged cancer cells, we will propose a few tactics to control it by using the principles of evolutionary biology. We hope that with appropriate therapeutic intervention, this detrimental cellular fate could be diverted in favor of TNBC patients.

Butein induces cellular senescence through reactive oxygen species-mediated p53 activation in osteosarcoma U-2 OS cells

Butein is a flavonoid isolated from various medicinal plants. It is known to have different biological activities including anti-inflammation, anti-adipogenesis, and anti-angiogenesis. In the study, we demonstrated the anti-proliferative effect of butein in human osteosarcoma U-2 OS cells. Our data showed that butein significantly suppressed the viability and colony formation ability of U-2 OS cells. Further experiments revealed butein exposure resulted in a cell cycle arrest at S and G2/M phase in U-2 OS cells. Importantly, we found that butein activated the tumor suppressor p53, and trigged a p53-dependent senescence in U-2 OS cells. Knockdown of p53 suppressed the senescence and rescued the viability in butein-treated U-2 OS cells. Furthermore, we observed that butein exposure significantly enhanced reactive oxygen species (ROS) levels in U-2 OS cells. Co-administration of the ROS inhibitor NAC largely abolished the up-regulated p53 protein level, and rescued the suppressed viability and colony formation ability in butein-exposed U-2 OS cells. Taken together, our data proposed the increased ROS by butein exposure activated p53, and the activated p53 was involved in the anti-proliferative effect of butein via inducing senescence in U-2 OS cells. This report suggests that butein is a promising candidate for cancer therapy against osteosarcoma.

Cancer and Aging: Two Tightly Interconnected Biological Processes

Age is one of the main risk factors of cancer; several biological changes linked with the aging process can explain this. As our population is progressively aging, the proportion of older patients with cancer is increasing significantly. Due to the heterogeneity of general health and functional status amongst older persons, treatment of cancer is a major challenge in this vulnerable population. Older patients often experience more side effects of anticancer treatments. Over-treatment should be avoided to ensure an optimal quality of life. On the other hand, under-treatment due to fear of toxicity is a frequent problem and can lead to an increased risk of relapse and worse survival. There is a delicate balance between benefits of therapy and risk of toxicity. Robust biomarkers that reflect the body's biological age may aid in outlining optimal individual treatment regimens for older patients with cancer. In particular, the impact of age on systemic immunity and the tumor immune infiltrate should be considered, given the expanding role of immunotherapy in cancer treatment. In this review, we summarize current knowledge concerning the mechanistic connections between aging and cancer, as well as aging biomarkers that could be helpful in the field of geriatric oncology.

Shortened relative leukocyte telomere length is associated with all-cause mortality in type 2 diabetes- analysis from the Hong Kong Diabetes Register

AIMS

Few studies have investigated the relationship between rLTL and mortality in patients with type 2 diabetes in a large prospective study, particularly in the Asian population. This study investigates the relationship between rLTL and the risk of death in Chinese patients with type 2 diabetes.

METHODS

Consecutive Chinese patients with type 2 diabetes (N = 5349) from the Hong Kong Diabetes Register with stored baseline DNA and available follow-up data were studied. rLTL was measured using a quantitative polymerase chain reaction. Mortality and clinical outcomes were obtained based on ICD-9 codes.

RESULTS

The mean (SD) age of the subjects was 57.5 (13.3) years and mean (SD) follow-up duration was 13.4 (5.5) years. Baseline rLTL was significantly shorter in the 1925 subjects who subsequently died compared with the remaining subjects (4.3 ± 1.2 vs. 4.7 ± 1.2, P < 0.001). Shorter rLTL was associated with a higher risk of mortality (HR: 1.19 (1.14-1.23), P < 0.001), which remained significant after adjusting for traditional risk factors.

CONCLUSIONS

Shorter rLTL was significantly associated with an increased risk of all-cause and CVD mortality in patients with type 2 diabetes, independent of established risk factors. Telomere length may be a useful biomarker for mortality risk in patients with type 2 diabetes.

Senolytics for Cancer Therapy: Is All That Glitters Really Gold?

Simple Summary

Senescence is an essential component of tumor cell biology and is a primary cell stress response to therapy. While the long-term impact of senescence in cancer therapy is not yet fully understood, the use of senolytics, drugs that selectively kill senescent cells, is an area of active investigation in cancer treatment. Several challenges and unanswered questions have arisen from the current preclinical literature, indicating the need to re-evaluate some of the basic premises and experimental approaches, as well as the potential utility for translating to the clinic the application of senolytics as adjuvants to current cancer therapy.

Abstract

Senolytics represent a group of mechanistically diverse drugs that can eliminate senescent cells, both in tumors and in several aging-related pathologies. Consequently, senolytic use has been proposed as a potential adjuvant approach to improve the response to senescence-inducing conventional and targeted cancer therapies. Despite the unequivocal promise of senolytics, issues of universality, selectivity, resistance, and toxicity remain to be further clarified. In this review, we attempt to summarize and analyze the current preclinical literature involving the use of senolytics in senescent tumor cell models, and to propose tenable solutions and future directions to improve the understanding and use of this novel class of drugs.

Diabetes, metabolic disease, and telomere length

Telomeres are regions of repetitive nucleotide sequences at the ends of chromosomes. Telomere length is a marker of DNA damage, which is often considered a biomarker for biological ageing, and has also been linked with cardiovascular disease, diabetes, and cancer. Emerging studies have highlighted the role of genetic and environmental factors, and explored the effect of modulating telomere length. We provide an overview of studies to date on diabetes and telomere length, and compare different methods and assays for evaluating telomere length and telomerase activity. We highlight the limitations of current studies and areas that warrant further research to unravel the link between diabetes and telomere length. The value of adding telomere length to clinical risk factors to improve risk prediction of diabetes and related complications also merits further investigation.

Overdiagnosis in urologic cancer : For World Journal of Urology Symposium on active surveillance in prostate and renal cancer

BACKGROUND

Cancer, which historically was diagnosed at late and incurable stages, has expanded to a heterogeneous group of conditions that vary from clinically insignificant to rapidly aggressive and lethal. This evolution is due to the widespread use of screening tests for early detection of cancer, both directed (i.e., PSA, mammography, colonoscopy) and undirected (abdominal imaging). The use of these tests has resulted in both benefits and harms. The benefits are a reduction in survival and mortality, due to significant cancers being diagnosed at a more curable stage. The harms are an increase, in some cases dramatic, in the diagnosis of clinically insignificant disease. These are called 'cancer' but not destined to affect the patient's life, even in the absence of treatment.

METHODS

Non-explicit summary of the literature on overdiagnosis of cancer.

RESULTS

The phenomenon of overdiagnosis requires two factors: the presence of a common reservoir of microfocal disease and a screening test to find it. These factors exist for breast, prostate, skin, renal, and thyroid cancers, and to a lesser degree for lung cancer. The problem of cancer overdiagnosis and overtreatment is complex, with numerous etiologies and many tradeoffs. It is a particular problem in prostate cancer but is a major issue in many other cancer sites. Screening for prostate cancer based on the best data from prospective randomized trials significantly reduces cancer mortality. However, reducing overtreatment in patients diagnosed with indolent disease is critical to the success of screening.

CONCLUSION

Active surveillance, the focus of this series of articles, is an important strategy to reduce overtreatment. This article reviews the pathological, clinical, social, and psychological aspects of overdiagnosis in cancer.

Genetic Alterations in the INK4a/ARF Locus: Effects on Melanoma Development and Progression

Genetic alterations in the INK4a/ARF (or CDKN2A) locus have been reported in many cancer types, including melanoma; head and neck squamous cell carcinomas; lung, breast, and pancreatic cancers. In melanoma, loss of function CDKN2A alterations have been identified in approximately 50% of primary melanomas, in over 75% of metastatic melanomas, and in the germline of 40% of families with a predisposition to cutaneous melanoma. The CDKN2A locus encodes two critical tumor suppressor proteins, the cyclin-dependent kinase inhibitor p16^INK4a and the p53 regulator p14^ARF. The majority of CDKN2A alterations in melanoma selectively target p16^INK4a or affect the coding sequence of both p16^INK4a and p14^ARF. There is also a subset of less common somatic and germline INK4a/ARF alterations that affect p14^ARF, while not altering the syntenic p16^INK4a coding regions. In this review, we describe the frequency and types of somatic alterations affecting the CDKN2A locus in melanoma and germline CDKN2A alterations in familial melanoma, and their functional consequences in melanoma development. We discuss the clinical implications of CDKN2A inactivating alterations and their influence on treatment response and resistance.

Interaction effects of environmental response gene polymorphisms and benzene exposure on telomere length in shoe-making workers

Benzene is a globally occurring environmental and occupational pollutant that causes leukemia. To better understand telomere length (TL) as a function of benzene toxicity, we recruited 294 shoe-making workers and 102 controls from Wenzhou, China in 2011. Biomarkers of TL, cytokinesis-block micronucleus (MN) frequency, and white blood cells (WBC) were measured. In total, 18 polymorphic sites in environmental response genes, including metabolic and DNA repair genes, were analyzed. Results indicate that benzene exposure led to a longer TL at a threshold of 32 mg/m³-year of cumulative exposure dose (CED). Furthermore, the TL was longer in members of the damaged group, when evaluated for MN frequency (P < 0.001) and reduced WBC (P < 0.001), than in those of the normal group. Workers carrying genotype TT (β = 0.32, P = 0.042) in rs3212986 of ERCC1 and genotype TC (β = 0.24, P = 0.082) in rs1051740 of mEH exon3 were associated with a longer TL as compared to the wild-type group. TA (β = -0.53, P < 0.001) in rs6413432 of CYP2E1 was associated with a shorter TL. Benzene exposure interacted with the TA type in rs6413432 (β = 0.003, 95% CI: 0, 0.006, P = 0.042) and the CC type in rs1051740 (β = 0.007, 95% CI: 0.001, 0.013, P = 0.015) after adjusting for confounding factors. Our results indicate that benzene induces an increase in TL at a threshold of CED ≥32mg/m³-year. Rs1051740, rs3212986, and rs6413432 were found to be involved in benzene-induced telomere growth; in particular, rs1051740 and rs6413432 interacted with the benzene exposure, resulting in an extended TL.

Targeting senescent cells and tumor therapy (Review)

Cell senescence is caused by the activation of cell cycle inhibition pathways induced by an accumulation of cellular damage, where cells permanently leave the cell cycle. Senescent cells undergo changes in cell morphology, transcription, protein homeostasis, metabolism and other characteristic alterations. At the same time, senescent cells are able to resist apoptosis and accumulate in multiple organs and tissues in vivo. Senescent cells are capable of activating inflammatory factor secretion pathways, generating local, non-infectious inflammatory microenvironments within tissues, leading to organ degeneration and the development of aging-associated diseases. A large number of recently published studies have demonstrated that removing senescent cells from the body delays the occurrence of various aging-associated diseases. Therefore, the targeted killing of senescent cells potentially has important clinical applications in the treatment of various aging-associated diseases, aiming to improve the life span of patients. The present review summarizes recent progress that has been made in the field of senescent cell clearance and various anti-aging strategies. The history of cell senescence research is briefly reviewed, along with the association between cell senescence and tumor therapy. Furthermore, the potential of senescent cells to be used as therapeutic targets in various senescence-associated diseases is primarily discussed, and the limitations, as well as the future prospects of this line of research, are reviewed.

Growth Inhibitory Signaling of the Raf/MEK/ERK Pathway

In response to extracellular stimuli, the Raf/MEK/extracellular signal-regulated kinase (ERK) pathway regulates diverse cellular processes. While mainly known as a mitogenic signaling pathway, the Raf/MEK/ERK pathway can mediate not only cell proliferation and survival but also cell cycle arrest and death in different cell types. Growing evidence suggests that the cell fate toward these paradoxical physiological outputs may be determined not only at downstream effector levels but also at the pathway level, which involves the magnitude of pathway activity, spatial-temporal regulation, and non-canonical functions of the molecular switches in this pathway. This review discusses recent updates on the molecular mechanisms underlying the pathway-mediated growth inhibitory signaling, with a major focus on the regulation mediated at the pathway level.

Cellular Senescence and Anti-Cancer Therapy

BACKGROUND

Cellular senescence is generally understood as a permanent cell cycle arrest stemming from different causes. The mechanism of cellular senescence-induced cell cycle arrest is complex, involving interactions between telomere shortening, inflammations and cellular stresses. In recent years, a growing number of studies have revealed that cellular senescence could mediate the cancer progression of neighboring cells, but this idea is controversial and contradictory evidence argues that cellular senescence also contributes to tumor suppression.

OBJECTIVE

Given that the complicated role of senescence in various physiological and pathological scenarios, we try to clarify the precise contribution role of cellular senescence to tumor progression.

METHODS

Search for the information in a large array of relevant articles to support our opinion.

RESULTS

We discuss the relatively widespread occurrence of cellular senescence in cancer treatment and identify the positive and negative side of senescence contributed to tumor progression.

CONCLUSION

We argue that the availability of pro-senescence therapy could represent as a promising regimen for managing cancer disease, particularly with regard to the poor clinical outcome obtained with other anticancer therapies.

Phorbol myristate acetate induces cellular senescence in rat microglia in vitro

The present study aimed to establish a cellular model to test the hypothesis that oncogene-induced senescence (OIS) is triggered by aging-related activation of microglia. Primary microglia were incubated with phorbol 12-myristate 13-acetate (PMA), and β-galactosidase (β-Gal) staining was applied to subsequent assessment of cellular senescence. Moreover, flow cytometry was employed for examinations of cell cycle arrest and senescence-associated proteins, p53 and p21 were measured by western blotting. Furthermore, examination of tumor necrosis factor α (TNF-α) and interleukin-1β (IL-1β) were carried out with microglia supernatants undergoing age-related degenerative diseases in the nervous system, using ELISA. PC12 cells were co-cultured with microglia activated by aging-related alteration(s) to evaluate whether apoptosis was increased in PC12 cells. Cellular senescence-associated β-Gal staining showed that microglial β-Gal expression gradually increased with prolonged PMA stimulation. Microglia in the group receiving 72 h of PMA stimulation displayed the highest percentage of cells arrested in G0/G1, the highest amount of senescence-associated expression of p53 and p21, and the most prominent secretion of TNF-α and IL-1β. In comparison with controls, an increase of apoptotic PC12 cells was detected, which were co-cultured with aging microglia. Taken together, microglia tend to undergo senescence after PMA treatment, suggesting that microglial senescence is associated with inactivation of certain oncogenes.

Carnitine palmitoyltransferase 1C contributes to progressive cellular senescence

Stable transfection manipulation with antibiotic selection and passaging induces progressive cellular senescence phenotypes. However, the underlying mechanisms remain poorly understood. This study demonstrated that stable transfection of the empty vector induced PANC-1 cells into cellular senescence. Metabolomics revealed several acylcarnitines and their upstream regulatory gene, carnitine palmitoyltransferase 1C (CPT1C) involved in fatty acid β-oxidation in mitochondria, were strikingly decreased in senescent PANC-1 cells. Low CPT1C expression triggered mitochondrial dysfunction, inhibited telomere elongation, impaired cell survival under metabolic stress, and hindered the malignance and tumorigenesis of senescent cells. On the contrary, mitochondrial activity was restored by CPT1C gain-of-function in senescent vector PANC-1 cells. PPARα and TP53/CDKN1A, crucial signaling components in cellular senescence, were downregulated in senescent PANC-1 cells. This study identifies CPT1C as a key regulator of stable transfection-induced progressive PANC-1 cell senescence that inhibits mitochondrial function-associated metabolic reprogramming. These findings confirm the need to identify cell culture alterations after stable transfection, particularly when cells are used for metabolomics and mitochondria-associated studies, and suggest inhibition of CPT1C could be a promising target to intervene pancreatic tumorigenesis.

Cancer immune control needs senescence induction by interferon-dependent cell cycle regulator pathways in tumours

Immune checkpoint blockade (ICB)-based or natural cancer immune responses largely eliminate tumours. Yet, they require additional mechanisms to arrest those cancer cells that are not rejected. Cytokine-induced senescence (CIS) can stably arrest cancer cells, suggesting that interferon-dependent induction of senescence-inducing cell cycle regulators is needed to control those cancer cells that escape from killing. Here we report in two different cancers sensitive to T cell-mediated rejection, that deletion of the senescence-inducing cell cycle regulators p16^Ink4a/p19^Arf (Cdkn2a) or p21^Cip1 (Cdkn1a) in the tumour cells abrogates both the natural and the ICB-induced cancer immune control. Also in humans, melanoma metastases that progressed rapidly during ICB have losses of senescence-inducing genes and amplifications of senescence inhibitors. Metastatic cells also resist CIS. Such genetic and functional alterations are infrequent in metastatic melanomas regressing during ICB. Thus, activation of tumour-intrinsic, senescence-inducing cell cycle regulators is required to stably arrest cancer cells that escape from eradication.

The growth of cancer cells can be stably arrested by cytokine-induced senescence. Here, the authors show that cancers with defects in senescence-inducing cell cycle regulator pathways are resistant to immune checkpoint blockade.

The Emerging Role of Senescence in Ocular Disease

Cellular senescence is a state of irreversible cell cycle arrest in response to an array of cellular stresses. An important role for senescence has been shown for a number of pathophysiological conditions that include cardiovascular disease, pulmonary fibrosis, and diseases of the skin. However, whether senescence contributes to the progression of age-related macular degeneration (AMD) has not been studied in detail so far and the present review describes the recent research on this topic. We present an overview of the types of senescence, pathways of senescence, senescence-associated secretory phenotype (SASP), the role of mitochondria, and their functional implications along with antisenescent therapies. As a central mechanism, senescent cells can impact the surrounding tissue microenvironment via the secretion of a pool of bioactive molecules, termed the SASP. An updated summary of a number of new members of the ever-growing SASP family is presented. Further, we introduce the significance of mechanisms by which mitochondria may participate in the development of cellular senescence. Emerging evidence shows that extracellular vesicles (EVs) are important mediators of the effects of senescent cells on their microenvironment. Based on recent studies, there is reasonable evidence that senescence could be a modifiable factor, and hence, it may be possible to delay age-related diseases by modulating basic aging mechanisms using SASP inhibitors/senolytic drugs. Thus, antisenescent therapies in aging and age-related diseases appear to have a promising potential.

Erdheim-Chester disease: An in vivo human model of Mϕ activation at the crossroad between chronic inflammation and cancer

Erdheim-Chester disease (ECD) is a rare histiocytosis characterized by infiltration of multiple tissues by CD68⁺ foamy Mϕs (or 'histiocytes'). Clinical manifestations arise from mass-forming lesions or from tissue and systemic inflammation. ECD histiocytes harbor oncogenic mutations along the MAPK-kinase signaling pathway (BRAF^V600E in more than half of the patients), and secrete abundant pro-inflammatory cytokines and chemokines. Based on these features, ECD is considered an inflammatory myeloid neoplasm, and is accordingly managed with targeted kinase inhibitors or immunosuppressive and cytokine-blocking agents. Evidence is emerging that maladaptive metabolic changes, particularly up-regulated glycolysis, represent an additional, mutation-driven feature of ECD histiocytes, which sustains deregulated and protracted pro-inflammatory activation and cytokine production. Besides translational relevance to the management of ECD patients and to the development of new therapeutic approaches, recognition of ECD as a natural human model of chronic, maladaptive Mϕ activation instructs the understanding of Mϕ dysfunction in other chronic inflammatory conditions.

Chromosome arm aneuploidies shape tumour evolution and drug response

Chromosome arm aneuploidies (CAAs) are pervasive in cancers. However, how they affect cancer development, prognosis and treatment remains largely unknown. Here, we analyse CAA profiles of 23,427 tumours, identifying aspects of tumour evolution including probable orders in which CAAs occur and CAAs predicting tissue-specific metastasis. Both haematological and solid cancers initially gain chromosome arms, while only solid cancers subsequently preferentially lose multiple arms. 72 CAAs and 88 synergistically co-occurring CAA pairs multivariately predict good or poor survival for 58% of 6977 patients, with negligible impact of whole-genome doubling. Additionally, machine learning identifies 31 CAAs that robustly alter response to 56 chemotherapeutic drugs across cell lines representing 17 cancer types. We also uncover 1024 potential synthetic lethal pharmacogenomic interactions. Notably, in predicting drug response, CAAs substantially outperform  mutations and focal deletions/amplifications combined. Thus, CAAs predict cancer prognosis, shape tumour evolution, metastasis and drug response, and may advance precision oncology.

Fasting Serum Levels of Potassium and Sodium in Relation to Long-Term Risk of Cancer in Healthy Men

Purpose

To examine whether serum levels of potassium and sodium were associated with long-term cancer risk in initially healthy men.

Patients and Methods

A cohort of 1994 initially healthy men with no use of medication, aged 40–59 years, was followed for cancer during 40 years of follow-up. Associations between fasting electrolyte levels and cancer risk were assessed with incidence rates and Cox proportional hazards models.

Results

Potassium, but not sodium, was linearly associated with cancer risk. This association remained significant after adjustment of several potential confounding factors, and also after excluding the first 10 years of follow-up. The age-adjusted risk of all-site cancer increased with 16% for each SD increase in potassium level. Men with hyperkalemia showed an incidence rate that was 40% higher than for men with normal potassium levels.

Conclusion

Fasting serum potassium level in healthy men was positively associated with long-term cancer risk. Potassium or potassium ion channels may have a role in cell proliferation or differentiation. These findings might imply future cancer strategies for targeting individuals with high serum potassium levels.

Premature cell senescence in human skin: Dual face in chronic acquired pigmentary disorders

Although senescence was originally described as an in vitro acquired cellular characteristic, it was recently recognized that senescence is physiologically and pathologically involved in aging and age-related diseases in vivo. The definition of cellular senescence has expanded to include the growth arrest caused by various cellular stresses, including DNA damage, inadequate mitochondria function, activated oncogene or tumor suppressor genes and oxidative stress. While senescence in normal aging involves various tissues over time and contributes to a decline in tissue function even with healthy aging, disease-induced premature senescence may be restricted to one or a few organs triggering a prolonged and more intense rate of accumulation of senescent cells than in normal aging. Organ-specific high senescence rate could lead to chronic diseases, especially in post-mitotic rich tissue. Recently, two opposite acquired pathological conditions related to skin pigmentation were described to be associated with premature senescence: vitiligo and melasma. In both cases, it was demonstrated that pathological dysfunctions are not restricted to melanocytes, the cell type responsible for melanin production and transport to surrounding keratinocytes. Similar to physiological melanogenesis, dermal and epidermal cells contribute directly and indirectly to deregulate skin pigmentation as a result of complex intercellular communication. Thus, despite senescence usually being reported as a uniform phenotype sharing the expression of characteristic markers, skin senescence involving mainly the dermal compartment and its paracrine function could be associated with the disappearance of melanocytes in vitiligo lesions and with the exacerbated activity of melanocytes in the hyperpigmentation spots of melasma. This suggests that the difference may arise in melanocyte intrinsic differences and/or in highly defined microenvironment peculiarities poorly explored at the current state of the art. A similar dualistic phenotype has been attributed to intratumoral stromal cells as cancer-associated fibroblasts presenting a senescent-like phenotype which influence the behavior of neoplastic cells in either a tumor-promoting or tumor-inhibiting manner. Here, we present a framework dissecting senescent-related molecular alterations shared by vitiligo and melasma patients and we also discuss disease-specific differences representing new challenges for treatment.

Fibronectin in Cancer: Friend or Foe

The role of fibronectin (FN) in tumorigenesis and malignant progression has been highly controversial. Cancerous FN plays a tumor-suppressive role, whereas it is pro-metastatic and associated with poor prognosis. Interestingly, FN matrix deposited in the tumor microenvironments (TMEs) promotes tumor progression but is paradoxically related to a better prognosis. Here, we justify how FN impacts tumor transformation and subsequently metastatic progression. Next, we try to reconcile and rationalize the seemingly conflicting roles of FN in cancer and TMEs. Finally, we propose future perspectives for potential FN-based therapeutic strategies.

SASP-Dependent Interactions between Senescent Cells and Platelets Modulate Migration and Invasion of Cancer Cells

Alterations in platelet aggregation are common in aging individuals and in the context of age-related pathologies such as cancer. So far, however, the effects of senescent cells on platelets have not been explored. In addition to serving as a barrier to tumor progression, cellular senescence can contribute to remodeling tissue microenvironments through the capacity of senescent cells to synthesize and secrete a plethora of bioactive factors, a feature referred to as the senescence-associated secretory phenotype (SASP). As senescent cells accumulate in aging tissues, sites of tissue injury, or in response to drugs, SASP factors may contribute to increase platelet activity and, through this mechanism, generate a microenvironment that facilitates cancer progression. Using in vitro models of drug-induced senescence, in which cellular senescence was induced following exposure of mammary epithelial cells (MCF-10A and MCF-7) and gastric cancer cells (AGS) to the CDK4/6 inhibitor Palbociclib, we show that senescent mammary and gastric cells display unique expression profiles of selected SASP factors, most of them being downregulated at the RNA level in senescent AGS cells. In addition, we observed cell-type specific differences in the levels of secreted factors, including IL-1β, in media conditioned by senescent cells. Interestingly, only media conditioned by senescent MCF-10A and MCF-7 cells were able to enhance platelet aggregation, although all three types of senescent cells were able to attract platelets in vitro. Nevertheless, the effects of factors secreted by senescent cells and platelets on the migration and invasion of non-senescent cells are complex. Overall, platelets have prominent effects on migration, while factors secreted by senescent cells tend to promote invasion. These differential responses likely reflect differences in the specific arrays of secreted senescence-associated factors, specific factors released by platelets upon activation, and the susceptibility of target cells to respond to these agents.

Role of melanoma inhibitory activity in melanocyte senescence

The protein melanoma inhibitory activity (MIA) is known to be expressed in melanoma and to support melanoma progression. Interestingly, previous studies also observed the expression of MIA in nevi. Concentrating on these findings, we revealed that MIA expression is correlated with a senescent state in melanocytes. Induction of replicative or oncogene-induced senescence resulted in increased MIA expression in vitro. Notably, MIA knockdown in senescent melanocytes reduced the percentage of senescence-associated beta-Gal-positive cells and enhanced proliferation. Using the melanoma mouse model Tg(Grm1), MIA-deficient mice supported the impact of MIA on senescence by showing a significantly earlier tumor onset compared to controls. In melanocytes, MIA knockdown led to a downregulation of the cell cycle inhibitor p21 in vitro and in vivo. In contrast, after induction of hTERT in human melanoma cells, p21 regulation by MIA was lost. In summary, our data show for the first time that MIA is a regulator of cellular senescence in human and murine melanocytes.

Chromatin remodeling factor BAZ1A regulates cellular senescence in both cancer and normal cells

AIMS

Cellular senescence is a well-known cancer prevention mechanism, inducing cancer cells to senescence can enhance cancer immunotherapy. However, how cellular senescence is regulated is not fully understood. Dynamic chromatin changes have been discovered during cellular senescence, while the causality remains elusive. BAZ1A, a gene coding the accessory subunit of ATP-dependent chromatin remodeling complex, showed decreased expression in multiple cellular senescence models. We aim to investigate the functional role of BAZ1A in regulating senescence in cancer and normal cells.

MATERIALS AND METHODS

Knockdown of BAZ1A was performed via lentivirus mediated short hairpin RNA (shRNA) in various cancer cell lines (A549 and U2OS) and normal cells (HUVEC, NIH3T3 and MEF). A series of senescence-associated phenotypes were quantified by CCK-8 assay, SA-β-Gal staining and EdU incorporation assay, etc. KEY FINDINGS: Knockdown (KD) of BAZ1A induced series of senescence-associated phenotypes in both cancer and normal cells. BAZ1A-KD caused the upregulated expression of SMAD3, which in turn activated the transcription of p21 coding gene CDKN1A and resulted in senescence-associated phenotypes in human cancer cells (A549 and U2OS).

SIGNIFICANCE

Our results revealed chromatin remodeling modulator BAZ1A acting as a novel regulator of cellular senescence in both normal and cancer cells, indicating a new target for potential cancer treatment.

Tropomyosin-Related Kinase Receptor and Neurotrophin Expression in Cutaneous Melanoma Is Associated with a Poor Prognosis and Decreased Survival

OBJECTIVE

Normally, activation of tropomyosin-related kinase (TRK) receptors by neurotrophins (NTs) stimulates intracellular pathways involved in cell survival and proliferation. Dysregulation of NT/TRK signaling may affect neoplasm prognosis. Data on NT and TRK expression in melanomas are limited, and it is unclear whether NT/TRK signaling pathways are involved in the origin and progression of this neoplasm.

METHODS

We examined whether NT/TRK expression differs across different cutaneous melanoma grades and subtypes, and whether it is associated with melanoma prognosis and survival. A cross-sectional study was performed in which the expression of TrkA, TrkB, nerve growth factor (NGF), and brain-derived neurotrophic factor (BDNF) was analyzed by immunohistochemistry of 154 melanoma samples. We investigated NT/TRK expression associations with prognostic factors for melanoma, relapse-free survival (RFS), and overall survival (OS).

RESULTS

Of the 154 melanoma samples, 77 (55.4%) were TrkA immunopositive, 81 (58.3%) were TrkB immunopositive, 113 (81.3%) were BDNF immunopositive, and 104 (75.4%) were NGF immunopositive. We found NT/TRK expression associated strongly with several clinical prognostic factors, including the tumor-node-metastasis stage (p < 0.001), histological subtype (p < 0.001), and Clark level (p < 0.05), as well as with a worse OS (p < 0.05 for all, except TrkB) and RFS (p < 0.05 for all).

CONCLUSIONS

Our results show strong associations of NT/TRK expression with melanoma stage progression and a poor prognosis.

Cancer events in Belgian nursing home residents: An EORTC prospective cohort study

OBJECTIVES

This prospective multicenter cohort study aimed to describe new cancer events in nursing home residents (NHR).

MATERIALS AND METHODS

The study was performed in 39 nursing homes from the Armonea network in Belgium, covering 4262 nursing home beds. All NHR in these homes were prospectively followed during 1 year for occurrence of cancer events (diagnosis or clinical suspicion of a new cancer or progression of a known cancer). After training, each site's local staff identified NHR with cancer events in collaboration with the treating general practitioner (GP). NHR with cancer events were included after informed consent, and data about general health and cancer status were collected every 3 months up to 2 years.

RESULTS

In only nine NHR (median age 87 years, range 72-92), a cancer event was recorded during follow-up including five new (suspected or diagnosed) cancer events (incidence rate = 123/100.000 NHR per year) and four NHR with (suspected or diagnosed) progressive disease. In four NHR with suspected cancer, no diagnostic procedure was performed, and in five no anticancer treatment was started.

CONCLUSION

Clinically relevant cancer events (potentially requiring diagnostic or therapeutic action) occur at a much lower frequency in NHR than expected from cancer incidence data in the general older population. Although some underreporting of cancer events cannot be excluded, this prospective study supports several previous retrospective observations that cancer events are rare in very frail older persons. Moreover, diagnostic and therapeutic actions for (suspected) cancer events are often not undertaken in this population.

Ovarian insufficiency and CTNNB1 mutations drive malignant transformation of endometrial hyperplasia with altered PTEN/PI3K activities

Endometrioid endometrial carcinomas (EECs) carry multiple driver mutations even when they are low grade. However, the biological significance of these concurrent mutations is unknown. We explored the interactions among three signature EEC mutations: loss-of-function (LOF) mutations in PTEN, gain-of-function (GOF) mutations of phosphoinositide 3-kinase (PI3K), and CTNNB1 exon 3 mutations, utilizing in vivo mutagenesis of the mouse uterine epithelium. While epithelial cells with a monoallelic mutation in any one of three genes failed to propagate in the endometrium, any combination of two or more mutant alleles promoted the growth of epithelium, causing simple hyperplasia, in a dose-dependent manner. Notably, Ctnnb1 exon 3 deletion significantly increased the size of hyperplastic lesions by promoting the growth of PTEN LOF and/or PI3K GOF mutant cells through the activation of neoadenogenesis pathways. Although these three mutations were insufficient to cause EEC in intact female mice, castration triggered malignant transformation, leading to myometrial invasion and serosal metastasis. Treatment of castrated mice with progesterone or estradiol attenuated the neoplastic transformation. This study demonstrates that multiple driver mutations are required for premalignant cells to break the growth-repressing field effect of normal endometrium maintained by ovarian steroids and that CTNNB1 exon 3 mutations play critical roles in the growth of preneoplastic cells within the endometrium of premenopausal women and in the myometrial invasion of EECs in menopausal women.