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AUTOPHAGY AND MICRONUCLEI ELIMINATION IN MCF-7 HUMAN BREAST ADENOCARCINOMA CELLSтезисы доклада Тезисы
- Авторы: Kisurina-Evgenieva O.P., Sutyagina O.I., Onishchenko G.E.
- Сборник: МЕЖДУНАРОДНАЯ КОНФЕРЕНЦИЯ «MOLECULAR MECHANISMS OF AUTOPHAGY IN DISEASES». 30-31 ОКТЯБРЯ 2020 ГОДА, САНКТ-ПЕТЕРБУРГ – СБОРНИК ТЕЗИСОВ – : 2020. – 48 С
- Тезисы
- Год издания: 2020
- Место издания: СПБ
- Первая страница: 24
- Последняя страница: 24
- Аннотация: ObjectiveMicronuclei (MN) are small DNA-containing structures separated from the cell nucleus.The presence of MN in p53-positive cells causes cell cycle arrest and triggers the apoptosis.Tumor cells often have mutations in the p53 gene and avoid apoptosis. On the other hand, it hasbeen found that MN in tumor cells can be eliminated. The following pathways for elimination ofMN are: collapse of the micronucleus membrane with subsequent DNA destruction,fragmentation and degradation of micronuclear DNA while maintaining the intact micronuclearmembrane, direct extrusion by blebbing, and autophagic degradation.Materials and methodsThe purpose of this study was to investigate the possibility of MN elimination byautophagy in cultured MCF-7 cells (human breast adenocarcinoma cells, p53+). To stimulate theformation of MN, the cells were exposed to paclitaxel (125 nM, 48 h) with subsequent removal ofthe agent (for 24 h). The colocalized staining of micronuclei (Hoechst 33142) and acidiccompartment (LysoTracer® Red DND-99) was analyzed to identify the possible autophagicdegradation of MN. Two groups of MN were observed in both intact and paclitaxel-treated MCF-7cultures: large multiple (average size 40 μm2) and single small MN (0.35 μm2). The cell numberwith single MN was 12.7±0.06% in intact culture and did not alter after cell treatment withpaclitaxel. The cell number with large multiple MN was 1.2±0.4% in the control and 41.7±3.1%after paclitaxel exposure. The autophagic degradation was showed only for single small MN. Itwas rare in both control and after paclitaxel treatment (0.13±0.15%). However, significantproportion of cells with MN that have entered apoptosis fall out of the sample. In order toconsider the possible fate of micronuclei in this group of cells, the apoptotic death wassuppressed with pan-caspase inhibitor ZVAD-fmk (20 nM, 24 h after paclitaxel exposure). Theaddition of ZVAD-fmk decreased the apoptotic index from 7.5±1.1% to 0.06±0.11% andincreased the number of lysosome degradation of small single MN to 6.3±0.4%. One possibleexplanation is the maintenance of a balance of apoptosis/autophagy processes in cells.Presumably, apoptosis is predominantly induced in MCF-7 cells with MN (p53+) and theautophagic scenario does not have time to be realized. Blocking of apoptosis shifts the balancetoward autophagy. The colocalization of large multiple MN with components of the acidiccompartment was not identified.ConclusionsThus, it can be argued that lysosome-mediated degradation of small single MN is a real,but extremely rare, pathway of elimination.
- Добавил в систему: Кисурина-Евгеньева Ольга Петровна