Effect of inducible overexpression of NRASWT or NRASQ61R in human epidermal melanocytes
Ontology highlight
ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE345642 | GEO | 2026/09/09
REPOSITORIES: GEO
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Project description:As normal cells approach their proliferative limit, they arrest to undergo replicative senescence, displaying large cell size, flat morphology and activation of senescence-associated beta-galactosidase (SA-b-Gal). A subset of normal or tumor cells exposed in vitro or in vivo to chemotherapy agents such as etoposide perform a related response with a similar cellular phenotype dubbed therapy-induced senescence (TIS). High cellular heterogeneity in samples including TIS cells can impede confident determination of senescence-specific factors, frustrating discovery of markers and targets for functional analysis. As a TIS study model, we treated murine melanoma cells with the chemotherapeutic etoposide, applied a live-cell fluorescent SA-b-Gal senescence assay, and utilized fluorescence-activated cell sorting (FACS) to enrich TIS cells. Enriched senescent cell samples were subjected to mass spectrometry and label-free quantitative proteomics analysis, alongside proliferating and quiescent cell samples. Systems biology analysis revealed that senescent cells overexpress proteins and pathways regulating glycolipid processing, lipid metabolism, and lipid peroxidation. Senescence-associated activation of numerous glycosidases was observed, along with elevated cell surface expression of several major lipid regulatory proteins. Senescent cells were found to contain abundant lipid droplets and to import various types of extracellular lipids in correlation with extent of SA-b-Gal expression, and tumor cells were observed to spontaneously senesce in the presence of excess ceramide or triglycerides. Redox-induced lipid peroxidation, resulting in accumulation of cellular reactive aldehydes and consequent expression of aldehyde detoxification enzymes, was observed to be a key feature of TIS induced by three DNA-damaging chemotherapeutics.
2017-11-06 | PXD006216 | Pride
Project description:Ferroptotic cell death is dependent on unrestricted lipid peroxidation rather than activation of apoptotic effector caspases. A large number of ferroptosis activators have been reported recently. We used gene sequencing to analyze the effects of four ferroptosis activators (RSL3, N6F11, Fin56 and Erastin) on global gene expression in human PDAC1 cell line.
2023-10-18 | E-MTAB-12241 | biostudies-arrayexpress
Project description:Senescent cells drive ageing and age-related pathologies, including cancer. Consequently, senolytics, drugs that selectively kill senescent cells, have a broad therapeutic appeal. Here, we report a senolytic screen of a library of 10,480 covalent fragments. Amongst 38 identified hits, we found a subset of chloroacetamides with broad senolytic activity. Activity-based protein profiling, coupled with functional assays, identified the glutathione peroxidase GPX4 as their target. We show that senescent cells are primed for ferroptosis, displaying high levels of oxidative stress, intracellular Fe2+, and enhanced lipid oxidation, but also upregulate GPX4, which protects them from ferroptosis. Consequently, treatment with senolytic chloroacetamides or GPX4 inhibitors selectively kills senescent cells by ferroptosis. The combination of anti-cancer therapies with GPX4 inhibitors eliminated senescent tumour cells and improved outcomes in models of prostate and ovarian cancer. Our results show that senescent cells rely on GPX4 to prevent ferroptosis and that GPX4 inhibitors kill senescent cells, having a wide therapeutic potential.
2026-02-23 | PXD068417 | Pride
Project description:Senescent cells drive ageing and age-related pathologies, including cancer. Consequently, senolytics, drugs that selectively kill senescent cells, have a broad therapeutic appeal. Here, we report a senolytic screen of a library of 10,480 covalent fragments. Amongst 44 identified hits, we found a subset of chloroacetamides with broad senolytic activity. Activity-based protein profiling, coupled with functional assays, identified the glutathione peroxidase GPX4 as their target. Senescent cells are primed for ferroptosis, displaying high levels of oxidative stress, intracellular Fe2+, and enhanced lipid oxidation, but also display increased levels of GPX4, which protects them from ferroptosis. Consequently, treatment with senolytic chloroacetamides or GPX4 inhibitors selectively kills senescent cells by ferroptosis. The combination of anti-cancer therapies with GPX4 inhibitors eliminated senescent tumour cells and improved outcomes in models of prostate and ovarian cancer. Our results show that senescent cells rely on GPX4 to prevent ferroptosis and that GPX4 inhibitors kill senescent cells, having a wide therapeutic potential.
2026-02-23 | PXD068572 | Pride
Project description:Ferroptosis is a form of regulated cell death characterized by iron-dependent lipid peroxidation. While ferroptosis has been identified as a mechanism for suppressing cancer, its overall physiological significance remains poorly understood. Recent studies have revealed that labile iron and lipid peroxides are released from ferroptotic cells, leading to the propagation of ferroptosis through lipid peroxidation. However, other specific effects of secreted factors derived from ferroptotic cells remain unclear. We constructed a model cell system capable of inducing ferroptosis by re-expressing the transcription factor BACH1, a potent inducer of ferroptosis, in immortalized mouse embryonic fibroblasts (iMEFs). We investigated the impact of the secreted factors from ferroptotic cells with the iMEFs. As a result, we observed that the administration of supernatant media from ferroptotic iMEFs activated proliferation of hepatoma cells and suppressed cellular senescence-like features. This suggested that ferroptotic MEFs secrete anti-senescent substances. Transcriptome analysis of ferroptotic MEFs revealed an increase in the secretion of longevity factor FGF21 in a BACH1-dependent manner. Furthermore, the anti-senescent effects of the supernatant media from these ferroptotic cells were canceled by the knockout of Fgf21. Totally, it is suggested that BACH1 promotes ferroptosis in fibroblasts and contributes to the suppression of cellular senescence in neighboring cells by inducing FGF21 secretion from fibroblasts. It was also discovered that BACH1 not only activates indirectly the transcription of FGF21 by enhancing ferroptotic stress but also increases FGF21 protein level by suppressing the selective autophagic degradation of FGF21 through the transcriptional repression for Sqstm1 and Lamp2a. This represents a dual mechanism of FGF21 upregulation mediated by BACH1, suggesting that BACH1 is a potent inducer of FGF21 expression. It was also found that the BACH1-ferroptosis-FGF21 axis can suppress obesity of mice under high fat diet or short lifespan of progeria mice, closely associated phenotypes with aging. The inhibition of these aging-related phenotypes is considered to be a novel physiological significance of ferroptosis, and BACH1 is considered to function as a longevity gene by promoting ferroptotsis and subsequent FGF21 expression.
2024-06-11 | GSE238147 | GEO
Project description:Ferroptosis is a form of regulated cell death driven by lipid peroxidation of polyunsaturated fatty acids (PUFAs). Endogenous PUFAs are nonconjugated PUFAs and their peroxidation proceeds via the hydrogen-atom transfer (HAT) mechanism. We previously reported that lipids with conjugated double bonds undergo lipid peroxidation mostly via a different mechanism, peroxyl radical addition (PRA), and were much more readily oxidizable than nonconjugated ones. In this study, we aim to elucidate the effects of various unsaturated lipids in sensitizing ferroptosis. We found that while some peroxidation-reactive lipids, such as 7-dehydrocholesterol, vitamins D3 and A, and coenzyme Q10, suppress ferroptosis, both nonconjugated and conjugated PUFAs enhanced cell death induced by RSL3, a ferroptosis inducer. Importantly, we showed that conjugated linolenic acid (CLA 18:3) could act as a ferroptosis inducer by itself and conjugated linoleic acid (CLA 18:2) was more potent in sensitizing cells to RSL3-induced cell death than any nonconjugated PUFAs. We next sought to elucidate the mechanism underlying the different ferroptosis-inducing potency of conjugated and nonconjugated PUFAs. Lipidomics revealed that conjugated and nonconjugated PUFAs are incorporated into distinct cellular lipid species. Furthermore, the different peroxidation mechanisms predict the formation of higher levels of reactive electrophilic aldehydes from conjugated PUFAs than nonconjugated PUFAs, which was confirmed by aldehyde-trapping and mass spectrometry. RNA sequencing revealed that protein processing in the endoplasmic reticulum and proteasome are among the most significantly upregulated pathways in cells treated with CLA 18:3, suggesting increased ER stress and activation of unfolded protein response. Significantly, using click chemistry, we observed increased protein adduction by oxidized lipids in cells treated with an alkynylated CLA 18:2 probe. These results suggest that protein damage by lipid electrophiles is a key step in ferroptosis.
2023-04-17 | GSE224249 | GEO
Project description:Melanocytes within benign human nevi are the paradigm for tumor suppressive senescent cells in a pre-malignant neoplasm. These cells typically contain mutations in either the BRAF or N-RAS oncogene and express markers of senescence, including p16. However, a nevus can contain 10s to 100s of thousands of clonal melanocytes and approximately 20-30% of melanoma are thought to arise in association with a pre-existing nevus. Neither observation is indicative of fail-safe senescence-associated proliferation arrest and tumor suppression. We set out to better understand the status of nevus melanocytes. Proliferation-promoting Wnt target genes, such as cyclin D1 and c-myc, were repressed in oncogene-induced senescent melanocytes in vitro, and repression of Wnt signaling in these cells induced a senescent-like state. In contrast, cyclin D1 and c-myc were expressed in many melanocytes of human benign nevi. Specifically, activated Wnt signalling in nevi correlated inversely with nevus maturation, an established dermatopathological correlate of clinical benignancy. Single cell analyses of lone epidermal melanocytes and nevus melanocytes showed that expression of proliferation-promoting Wnt targets correlates with prior proliferative expansion of p16-expressing nevus melanocytes. In a mouse model, activation of Wnt signaling delayed, but did not bypass, senescence of oncogene-expressing melanocytes, leading to massive accumulation of proliferation-arrested, p16-positive non-malignant melanocytes. We conclude that clonal hyperproliferation of oncogene-expressing melanocytes to form a nevus is facilitated by transient delay of senescence due to activated Wnt signaling. The observation that activation of Wnt signaling correlates inversely with nevus maturation, an indicator of clinical benignancy, supports the notion that persistent destabilization of senescence by Wnt signaling contributes to the malignant potential of nevi. We used RNA-Seq to detail the global programme of gene expression in primary human melanocytes which were Uninfected and BRAF600V induced cells
2013-08-01 | E-GEOD-46805 | biostudies-arrayexpress
Project description:Melanocytes within benign human nevi are the paradigm for tumor suppressive senescent cells in a pre-malignant neoplasm. These cells typically contain mutations in either the BRAF or N-RAS oncogene and express markers of senescence, including p16. However, a nevus can contain 10s to 100s of thousands of clonal melanocytes and approximately 20-30% of melanoma are thought to arise in association with a pre-existing nevus. Neither observation is indicative of fail-safe senescence-associated proliferation arrest and tumor suppression. We set out to better understand the status of nevus melanocytes. Proliferation-promoting Wnt target genes, such as cyclin D1 and c-myc, were repressed in oncogene-induced senescent melanocytes in vitro, and repression of Wnt signaling in these cells induced a senescent-like state. In contrast, cyclin D1 and c-myc were expressed in many melanocytes of human benign nevi. Specifically, activated Wnt signalling in nevi correlated inversely with nevus maturation, an established dermatopathological correlate of clinical benignancy. Single cell analyses of lone epidermal melanocytes and nevus melanocytes showed that expression of proliferation-promoting Wnt targets correlates with prior proliferative expansion of p16-expressing nevus melanocytes. In a mouse model, activation of Wnt signaling delayed, but did not bypass, senescence of oncogene-expressing melanocytes, leading to massive accumulation of proliferation-arrested, p16-positive non-malignant melanocytes. We conclude that clonal hyperproliferation of oncogene-expressing melanocytes to form a nevus is facilitated by transient delay of senescence due to activated Wnt signaling. The observation that activation of Wnt signaling correlates inversely with nevus maturation, an indicator of clinical benignancy, supports the notion that persistent destabilization of senescence by Wnt signaling contributes to the malignant potential of nevi. We used RNA-Seq to detail the global programme of gene expression in human melanoma cell lines
2013-08-01 | E-GEOD-46817 | biostudies-arrayexpress
Project description:Melanocytes within benign human nevi are the paradigm for tumor suppressive senescent cells in a pre-malignant neoplasm. These cells typically contain mutations in either the BRAF or N-RAS oncogene and express markers of senescence, including p16. However, a nevus can contain 10s to 100s of thousands of clonal melanocytes and approximately 20-30% of melanoma are thought to arise in association with a pre-existing nevus. Neither observation is indicative of fail-safe senescence-associated proliferation arrest and tumor suppression. We set out to better understand the status of nevus melanocytes. Proliferation-promoting Wnt target genes, such as cyclin D1 and c-myc, were repressed in oncogene-induced senescent melanocytes in vitro, and repression of Wnt signaling in these cells induced a senescent-like state. In contrast, cyclin D1 and c-myc were expressed in many melanocytes of human benign nevi. Specifically, activated Wnt signalling in nevi correlated inversely with nevus maturation, an established dermatopathological correlate of clinical benignancy. Single cell analyses of lone epidermal melanocytes and nevus melanocytes showed that expression of proliferation-promoting Wnt targets correlates with prior proliferative expansion of p16-expressing nevus melanocytes. In a mouse model, activation of Wnt signaling delayed, but did not bypass, senescence of oncogene-expressing melanocytes, leading to massive accumulation of proliferation-arrested, p16-positive non-malignant melanocytes. We conclude that clonal hyperproliferation of oncogene-expressing melanocytes to form a nevus is facilitated by transient delay of senescence due to activated Wnt signaling. The observation that activation of Wnt signaling correlates inversely with nevus maturation, an indicator of clinical benignancy, supports the notion that persistent destabilization of senescence by Wnt signaling contributes to the malignant potential of nevi. We used microarrays to detail the global programme of gene expression after lentiviral infection of BRAF in 3 replicates. Primary human melanocytes were infected/uninfected with lentivirus containing either an Empty Vector or activated BRAFV600E mutant in three biological replicates
2013-08-01 | E-GEOD-46801 | biostudies-arrayexpress
Project description:To investigated the functional characteristics and molecular mechanisms underlying senescence in UV irradiated melanocytes. We performed gene expression profiling analysis using data obtained from RNA-seq of 3 normal melanocytes and 3 UV-irradiated senescent melanocytes.
2023-04-03 | GSE228470 | GEO