CCNB2/SASP/Cathepsin B & PGE2 Axis Induce Cell Senescence Mediated Malignant Transformation
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ABSTRACT:
SUBMITTER: Wang Y
PROVIDER: S-EPMC8416730 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:The process of oncogene-induced senescence (OIS) and the conversion between OIS and malignant transformation during carcinogenesis is poorly understood. Here, we show that following overactivation of oncogene Ras in lung epithelial cells, high-level transforming growth factor β1 (TGF-β1)-activated SMAD3, but not SMAD2 or SMAD4, plays a determinant role in inducing cellular senescence independent of the p53/p16/p15 senescence pathways. Importantly, SMAD3 binds a potential tumor suppressor ATOH8 to form a transcriptional complex that directly represses a series of cell cycle-promoting genes and consequently causes senescence in lung epithelial cells. Interestingly, the prosenescent SMAD3 converts to being oncogenic and essentially facilitates oncogenic Ras-driven malignant transformation. Furthermore, depleting Atoh8 rapidly accelerates oncogenic Ras-driven lung tumorigenesis, and lung cancers driven by mutant Ras and Atoh8 loss, but not by mutant Ras only, are sensitive to treatment of a specific SMAD3 inhibitor. Moreover, hypermethylation of the ATOH8 gene can be found in approximately 12% of clinical lung cancer cases. Together, our findings demonstrate not only epithelial cellular senescence directed by a potential tumor suppressor-controlled transcriptional program but also an important interplay between the prosenescent and transforming effects of TGF-β/SMAD3, potentially laying a foundation for developing early detection and anticancer strategies.
| S-EPMC9934021 | biostudies-literature
Project description:Senescence of alveolar type II (ATII) cells, progenitors of the alveolar epithelium, is a pathological feature and contributes importantly to the pathogenesis of idiopathic pulmonary fibrosis. Despite recognition of the importance of ATII cell senescence in idiopathic pulmonary fibrosis pathogenesis, how ATII cell senescence is regulated and how senescent ATII cells contribute to lung fibrogenesis remain unclear. In this study, we show that TGF-β1 (transforming growth factor-β1), a most ubiquitous and potent profibrotic cytokine, induces plasminogen activator inhibitor-1 (PAI-1), a cell senescence and fibrosis mediator, and p16 as well as senescence, but not apoptosis, in primary mouse ATII cells. We also found that senescent ATII cells secrete various cytokines and chemokines, including IL-4 and IL-13, which stimulate the expression of genes associated with a profibrotic phenotype in alveolar macrophages. Similar responses were also observed in TGF-β1-treated rat ATII (L2) and rat macrophage NR8383 cells. Deletion of PAI-1 or inhibition of PAI-1 activity with a small molecule PAI-1 inhibitor, however, blocks TGF-β1-induced senescence as well as a senescence-associated secretory phenotype in ATII and L2 cells and, consequently, the stimulatory effects of the conditioned medium from senescent ATII/L2 cells on macrophages. Moreover, we show that silencing p16 ameliorates PAI-1 protein-induced ATII cell senescence and secretion of profibrotic mediators. Our data suggest that PAI-1 mediates TGF-β1-induced ATII cell senescence and secretion of profibrotic mediators through inducing p16, and they also suggest that senescent ATII cells contribute to lung fibrogenesis in part by activating alveolar macrophages through secreting profibrotic and proinflammatory mediators.
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Project description:The inflammatory factor IL6 secreted by bone marrow mesenchymal stem cells (BMSCs) in the tumor microenvironment (TME) facilitates the survival and therapeutic resistance of neuroblastoma (NB). Here, we found that IL6 expression in primary tumor tissues or bone marrow (BM) metastases was closely associated with the disease risk and prognosis of NB patients. IL6 secretion from immortalized BMSC (iBMSC) was directly regulated by NB cells and is involved in promoting the proliferation and metastasis of NB cells. Beta-Lapachone (ARQ-501, LPC), an ortho-naphthoquinone natural product, significantly prevented the iBMSC-induced malignant transformation effect on NB cells through suppressing the expression and secretion of IL6 from iBMSC in vitro and in vivo. Mechanistically, LPC disrupted the crosstalk between NB cells and iBMSC in an NQO1-dependent manner through blocking the Gal-3/Gal-3BP/IL6 axis. Our results reveal the effect of iBMSC-derived IL6 on TME-induced malignant transformation of NB cells, and provide theoretical basis for the clinical application of LPC as a potential IL6 inhibitor in high-risk refractory NB patients.
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Project description:Age-related accumulation of ploidy changes is associated with decreased expression of genes controlling chromosome segregation and cohesin functions. To determine the consequences of whole chromosome instability (W-CIN) we down-regulated the spindle assembly checkpoint component BUB1 and the mitotic cohesin SMC1A, and used four-color-interphase-FISH coupled with BrdU incorporation and analyses of senescence features to reveal the fate of W-CIN cells. We observed significant correlations between levels of not-diploid cells and senescence-associated features (SAFs). W-CIN induced DNA double strand breaks and elevated oxidative stress, but caused low apoptosis. SAFs of W-CIN cells were remarkably similar to those induced by replicative senescence but occurred in only 13 days versus 4 months. Cultures enriched with not-diploid cells acquired a senescence-associated secretory phenotype (SASP) characterized by IL1B, CXCL8, CCL2, TNF, CCL27 and other pro-inflammatory factors including a novel SASP component CLEC11A. These findings suggest that W-CIN triggers premature senescence, presumably to prevent the propagation of cells with an abnormal DNA content. Cells deviating from diploidy have the ability to communicate with their microenvironment by secretion of an array of signaling factors. Our results suggest that aneuploid cells that accumulate during aging in some mammalian tissues potentially contribute to age-related pathologies and inflammation through SASP secretion.
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Project description:The gene encoding the proto-oncogene GTPase RAS is frequently mutated in human cancers. Mutated RAS proteins trigger antiapoptotic and cell-proliferative signals and lead to oncogenesis. However, RAS also induces apoptosis and senescence, which may contribute to the eradication of cells with RAS mutations. We previously reported that Ras association domain family member 6 (RASSF6) binds MDM2 and stabilizes the tumor suppressor p53 and that the active form of KRAS promotes the interaction between RASSF6 and MDM2. We also reported that Unc-119 lipid-binding chaperone (UNC119A), a chaperone of myristoylated proteins, interacts with RASSF6 and regulates RASSF6-mediated apoptosis. In this study, using several human cancer cell lines, quantitative RT-PCR, RNAi-based gene silencing, and immunoprecipitation/-fluorescence and cell biology assays, we report that UNC119A interacts with the active form of KRAS and that the C-terminal modification of KRAS is required for this interaction. We also noted that the hydrophobic pocket of UNC119A, which binds the myristoylated peptides, is not involved in the interaction. We observed that UNC119A promotes the binding of KRAS to RASSF6, enhances the interaction between RASSF6 and MDM2, and induces apoptosis. Conversely, UNC119A silencing promoted soft-agar colony formation, migration, and invasiveness in KRAS-mutated cancer cells. We conclude that UNC119A promotes KRAS-mediated p53-dependent apoptosis via RASSF6 and may play a tumor-suppressive role in cells with KRAS mutations.
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Project description:Chronic arsenic exposure is associated with the development of urothelial carcinoma of the bladder (UCB). To elucidate the contribution of arsenic exposure to urothelial cancer stem cell (CSC) generation, we established an in vitro stepwise malignant model transformed by chronically exposing human urothelial cells to arsenic. Using this model, we found that chronic arsenic exposure endows urothelial cells with malignant stemness properties including increased expression of stemness-related factors such as SOX2, sphere formation, self-renewal, invasion and chemoresistance. SOX2 was gradually and irreversibly overexpressed in line with acquired sphere-forming and self-renewal abilities. Following gene set enrichment analyses of arsenic-exposed and arsenic-unexposed cells, we found COX2 as an enriched gene for oncogenic signature. Mechanistically, arsenic-induced COX2/PGE2 increases SOX2 expression that eventually promotes malignant stem cell generation and repopulation. In urine samples from 90 subjects exposed to arsenic and 91 control subjects, we found a significant linear correlation between SOX2 and COX2 expression and the potential of SOX2 and COX2 expression as urinary markers to detect subjects exposed to arsenic. Furthermore, the combination marker yielded a high sensitivity for UCB detection in a separate cohort. Finally, our in vitro model exhibits basal-type molecular features and dual inhibition of EGFR and COX2 attenuated stem cell enrichment more efficiently than an EGFR inhibitor alone. In conclusion, the COX2/PGE2-SOX2 axis promotes arsenic-induced malignant stem cell transformation. In addition, our findings indicate the possible use of SOX2 and COX2 expression as urinary markers for the risk stratification and detection of UCB.
| S-EPMC5938132 | biostudies-literature
Project description:Cellular senescence is a cell state involved in both physiological and pathological processes such as age-related diseases and cancer. While the mechanism of senescence is now well known, its role in tumorigenesis still remains very controversial. The positive and negative effects of senescence on tumorigenesis depend largely on the diversity of the senescent phenotypes and, more precisely, on the senescence-associated secretory phenotype (SASP). In this review, we discuss the modulatory effect of nitric oxide (NO) in SASP and the possible benefits of the use of NO donors or iNOS inducers in combination with senotherapy in cancer treatment.
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Project description:Carcinogenicity of carbon nanotubes is a major concern but has not been well addressed due to the lack of experimental models. Here, we show that chronic exposure to single-walled carbon nanotubes causes malignant transformation of human lung epithelial cells. The transformed cells induce tumorigenesis in mice and exhibit an apoptosis resistant phenotype characteristic of cancer cells. This study provides new evidence for carbon nanotube-induced carcinogenesis and indicates the potential role of p53 in the process.
| S-EPMC3135732 | biostudies-literature
Project description:The oncogenic mutation BRAFV600E is a common event in nevi and melanomas, which are aggressive skin tumors characterized by MAPK signaling pathway activation. It has been observed that mutated benign melanocytic lesions can remain unchanged for decades, but also proliferate or undergo oncogene-induced senescence. The purpose of this study was to investigate the presence of a gene expression signature in BRAFV600E mutated nevi compared to wild-type ones, all derived from sun exposed sites. Microdissected tissues from excisional biopsies of acquired nevi were analyzed to detect the presence of BRAF and NRAS mutations and to profile whole genome expression by means of oligonucleotide microarrays. BRAFV600E mutation was evidenced in 64% of nevi, while no NRAS mutations were detected. Functional analysis of genes differentially expressed between wild-type and mutated lesions pointed out the role of oxidative stress in causing the oncogenic BRAF mutation and that the direct consequence of constitutive activation of BRAF-MEK-ERK pathway, in a benign contest, is the activation of apoptosis, autophagy and senescence. Our data also indicate that in mutated lesions, p53 plays a crucial role in the maintenance of the benign status. In our study, in order to understand the role of BRAF mutation in acquired nevi, we performed gene expression profiling analysis on fourteen lesions derived from intermittently exposed sites, using whole genome oligonucleotide microarrays. Expression data were coupled with sequencing results on BRAF and NRAS genes and class comparison algorithms were applied to detect sequences differentially expressed between BRAFV600E and BRAFwt-NRASwt lesions. Some of the obtained results were further validated by Real-Time RT-PCR on an independent cohort of samples. Mutation analysis evidenced BRAF mutations in 64% of the common acquired nevi. All the mutations consisted in the substitution V600E (T1799A). No alteration was found on exon 11 of the BRAF gene nor on exons 1 and 2 of the NRAS gene, as expected since no lesion came from chronically exposed sites. Transcriptome analysis was carried out using oligo-microarrays and differential expression was tested applying the Linear Models package LIMMA available at www.bioconductor.org that uses Bayesian statistics to compute the probability of a gene being differentially expressed. Only 25 transcripts had B value greater then 2. We then performed a one-way ANOVA, dividing samples into three classes according to their BRAF mutational status (wt, ++, +++) as assessed by pyrosequencing. We found 2882 known transcripts by selecting those with ANOVA p-value<0.01 and increasing or decreasing expression trends along the three classes. Functional analysis was performed using the MetaCoreTM software package to identify overrepresented functional processes. BRAF signature, acquired nevi, gene expression profiling "++ and +++" refer to the percentage of alleles carrying the mutation in the *BRAF*V600E lesions. This has been assessed by pyrosequencing analysis (Venesio et al, 2008. PMID= 18408659).
2016-06-30 | E-GEOD-23976 | biostudies-arrayexpress
Project description:Senescent cells drive age-related tissue dysfunction partially through the induction of a chronic senescence-associated secretory phenotype (SASP)1. Mitochondria are major regulators of the SASP; however, the underlying mechanisms have not been elucidated2. Mitochondria are often essential for apoptosis, a cell fate distinct from cellular senescence. During apoptosis, widespread mitochondrial outer membrane permeabilization (MOMP) commits a cell to die3. Here we find that MOMP occurring in a subset of mitochondria is a feature of cellular senescence. This process, called minority MOMP (miMOMP), requires BAX and BAK macropores enabling the release of mitochondrial DNA (mtDNA) into the cytosol. Cytosolic mtDNA in turn activates the cGAS-STING pathway, a major regulator of the SASP. We find that inhibition of MOMP in vivo decreases inflammatory markers and improves healthspan in aged mice. Our results reveal that apoptosis and senescence are regulated by similar mitochondria-dependent mechanisms and that sublethal mitochondrial apoptotic stress is a major driver of the SASP. We provide proof-of-concept that inhibition of miMOMP-induced inflammation may be a therapeutic route to improve healthspan.
| S-EPMC10584674 | biostudies-literature