Cellular senescence is defined as irreversible cell cycle arrest caused by various processes that render viable cells non-functional, hampering normal tissue homeostasis. It has many endogenous and exogenous inducers, and is closely connected with age, age-related pathologies, DNA damage, degenerative disorders, tumor suppression and activation, wound healing, and tissue repair. However, the literature is replete with contradictory findings concerning its triggering mechanisms, specific biomarkers, and detection protocols. This may be partly due to the wide range of cellular and in vivo animal or human models of accelerated aging that have been used to study senescence and test senolytic drugs. This review summarizes recent findings concerning senescence, presents some widely used cellular and animal senescence models, and briefly describes the best-known senolytic agents.

• Klíčová slova
• aging, cellular model, mouse model, senescence, senolytics,
• MeSH
• biologické markery MeSH
• kontrolní body buněčného cyklu MeSH
• poškození DNA MeSH
• stárnutí buněk * genetika   MeSH
• stárnutí * genetika   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Názvy látek
• biologické markery MeSH

Aging involves tissue accumulation of senescent cells (SC) whose elimination through senolytic approaches may evoke organismal rejuvenation. SC also contribute to aging-associated pathologies including cancer, hence it is imperative to better identify and target SC. Here, we aimed to identify new cell-surface proteins differentially expressed on human SC. Besides previously reported proteins enriched on SC, we identified 78 proteins enriched and 73 proteins underrepresented in replicatively senescent BJ fibroblasts, including L1CAM, whose expression is normally restricted to the neural system and kidneys. L1CAM was: 1) induced in premature forms of cellular senescence triggered chemically and by gamma-radiation, but not in Ras-induced senescence; 2) induced upon inhibition of cyclin-dependent kinases by p16INK4a; 3) induced by TGFbeta and suppressed by RAS/MAPK(Erk) signaling (the latter explaining the lack of L1CAM induction in RAS-induced senescence); and 4) induced upon downregulation of growth-associated gene ANT2, growth in low-glucose medium or inhibition of the mevalonate pathway. These data indicate that L1CAM is controlled by a number of cell growth- and metabolism-related pathways during SC development. Functionally, SC with enhanced surface L1CAM showed increased adhesion to extracellular matrix and migrated faster. Our results provide mechanistic insights into senescence of human cells, with implications for future senolytic strategies.

• Klíčová slova
• MAPK pathway, SILAC, aging, mass spectrometry, proteomics,
• MeSH
• buněčná adheze fyziologie   MeSH
• buněčný cyklus MeSH
• down regulace MeSH
• fibroblasty MeSH
• kvantitativní polymerázová řetězová reakce MeSH
• lidé MeSH
• molekula buněčné adheze nervové L1 genetika   metabolismus   MeSH
• nádorové buněčné linie MeSH
• pohyb buněk fyziologie   MeSH
• polymerázová řetězová reakce s reverzní transkripcí MeSH
• regulace genové exprese účinky léků   účinky záření   MeSH
• RNA interference MeSH
• signální transdukce MeSH
• stárnutí buněk MeSH
• transformující růstový faktor beta metabolismus   farmakologie   MeSH
• záření gama MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• molekula buněčné adheze nervové L1 MeSH
• transformující růstový faktor beta MeSH

BACKGROUND: Senescence is a fundamental biological process implicated in various pathologies, including cancer. Regarding carcinogenesis, senescence signifies, at least in its initial phases, an anti-tumor response that needs to be circumvented for cancer to progress. Micro-RNAs, a subclass of regulatory, non-coding RNAs, participate in senescence regulation. At the subcellular level micro-RNAs, similar to proteins, have been shown to traffic between organelles influencing cellular behavior. The differential function of micro-RNAs relative to their subcellular localization and their role in senescence biology raises concurrent in situ analysis of coding and non-coding gene products in senescent cells as a necessity. However, technical challenges have rendered in situ co-detection unfeasible until now. METHODS: In the present report we describe a methodology that bypasses these technical limitations achieving for the first time simultaneous detection of both a micro-RNA and a protein in the biological context of cellular senescence, utilizing the new commercially available SenTraGorTM compound. The method was applied in a prototypical human non-malignant epithelial model of oncogene-induced senescence that we generated for the purposes of the study. For the characterization of this novel system, we applied a wide range of cellular and molecular techniques, as well as high-throughput analysis of the transcriptome and micro-RNAs. RESULTS: This experimental setting has three advantages that are presented and discussed: i) it covers a "gap" in the molecular carcinogenesis field, as almost all corresponding in vitro models are fibroblast-based, even though the majority of neoplasms have epithelial origin, ii) it recapitulates the precancerous and cancerous phases of epithelial tumorigenesis within a short time frame under the light of natural selection and iii) it uses as an oncogenic signal, the replication licensing factor CDC6, implicated in both DNA replication and transcription when over-expressed, a characteristic that can be exploited to monitor RNA dynamics. CONCLUSIONS: Consequently, we demonstrate that our model is optimal for studying the molecular basis of epithelial carcinogenesis shedding light on the tumor-initiating events. The latter may reveal novel molecular targets with clinical benefit. Besides, since this method can be incorporated in a wide range of low, medium or high-throughput image-based approaches, we expect it to be broadly applicable.

• Klíčová slova
• CDC6, Cancer, DNA damage response, In situ hybridization, Micro-RNAs, Oncogene-induced senescence, R loops, Replication stress, SenTraGorTM, rDNA,
• MeSH
• epitelové buňky metabolismus   MeSH
• genom MeSH
• jaderné proteiny metabolismus   MeSH
• karcinogeneze MeSH
• kultivované buňky MeSH
• lidé MeSH
• mikro RNA metabolismus   MeSH
• nádory glandulární a epitelové genetika   patologie   ultrastruktura   MeSH
• onkogeny * MeSH
• proteiny buněčného cyklu metabolismus   MeSH
• proteiny metabolismus   MeSH
• stanovení celkové genové exprese MeSH
• stárnutí buněk genetika   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• CDC6 protein, human MeSH Prohlížeč
• jaderné proteiny MeSH
• mikro RNA MeSH
• proteiny buněčného cyklu MeSH
• proteiny MeSH