magistrsko delo
Barbara Lipovšek (Avtor), Toni Petan (Mentor), Gregor Gunčar (Član komisije za zagovor), Marko Novinec (Član komisije za zagovor), Miha Pavšič (Komentor)

Povzetek

Lipidne kapljice (LK) so pred kratkim priznani citosolni organeli s primarno nalogo shranjevanja maščob. Sestavljene so iz sredice nevtralnih lipidov obdane z enim slojem fosfolipidov in proteinov. Njihovo število, sestava in velikost se nenehno spreminjajo glede na celične potrebe in okolje. Pomembno vlogo imajo pri agresivnih rakavih celicah, saj omogočajo njihovo preživetje v tumorskem okolju, ki je pogosto hipoksično in revno s hranili. Na površini fosfolipidnega monosloja LK je pripetih mnogo proteinov in encimov z različnimi biološkimi funkcijami. V predhodnem delu naše raziskovalne skupine smo ugotovili, da imajo LK pomembno vlogo pri celičnem odzivu na stres, ki ga povzroči pomanjkanje hranil. Predvidevamo, da se dinamične spremembe LK v odzivu na celični stres odražajo v spremenjeni sestavi njihovega proteoma. V tem delu smo želeli ugotoviti, kako se proteom LK spremeni, ko visokoinvazivne celice raka dojke MDA-MB-231 izpostavimo akutnemu pomanjkanju hranil. Intaktne LK smo izolirali iz stradajočih in kontrolnih celic, izvedli izolacijo proteinov, jih razgradili do peptidov in jih analizirali ter kvantificirali z masno spektrometrijo z uporabo pristopa LFQ (ang. "label-free quantification"). Od skupno 381 zaznanih proteinov smo jih 155 (41 %) uvrstili med kontaminante iz drugih celičnih razdelkov, 49 proteinov pa smo glede na dosedanje raziskave lahko povezali z delovanjem LK. Med slednjimi smo zaznali 15 »bona fide« proteinov LK, ki so jim v drugih raziskavah pripisali vezavo na LK. Identificirali smo kar 177 (47 %) proteinov, ki jih dosedanje študije niso povezale z delovanjem LK in predstavljajo nove, potencialno zanimive tarče za nadaljnje raziskave. Akutno stradanje celic raka dojke je močno vplivalo na sestavo proteoma LK. Izpostavili bi 20 proteinov z bistveno spremenjenim izražanjem: G0S2, CDC42, SNX12, CBX3, UBA52, HEBP1, RAC2, AUP1, TBCB, GLRX3, CAST, DBNL, NUCKS1, PTGES3, TXN, PRDX5, TCEAL3, ACSL3, LUC7L2 in HSD17B11. Poleg proteinov vpletenih v presnovo maščobnih kislin, holesterola in metabolizem LK (ACSL3, HSD17B11, HSD17B7, G0S2) smo zaznali proteine, ki sodelujejo pri ubikvitinaciji (UBA52, AUP1), vnetnih odzivih (PTGES3), vzdrževanju redoks ravnotežja v celici (TXN, PRDX5), vezikularnem transportu (TRAPPC3, LZTFL1), organizaciji citoskeleta (TBCB, DBNL) in jedrnih procesih (TCEAL3, NUCKS1). Ti rezultati kažejo na povezavo med dinamičnimi spremembami v proteomu LK in celičnem odzivu na stres. Rezultati tega dela so pomembni za nadaljnje raziskave še neznanih vlog številnih z LK povezanih proteinov pri presnovi in delovanju organela ob stradanju in drugih stresnih pogojih.

Ključne besede

lipidne kapljice;maščobne kisline;proteini;lipidni metabolizem;celični stres;stradanje;rak;proteom;magistrska dela;

Podatki

Jezik: Slovenski jezik
Leto izida:
Tipologija: 2.09 - Magistrsko delo
Organizacija: UL FKKT - Fakulteta za kemijo in kemijsko tehnologijo
Založnik: [B. Lipovšek]
UDK: 577.115:577.2(043.2)
COBISS: 31309315 Povezava se bo odprla v novem oknu
Št. ogledov: 439
Št. prenosov: 115
Ocena: 0 (0 glasov)
Metapodatki: JSON JSON-RDF JSON-LD TURTLE N-TRIPLES XML RDFA MICRODATA DC-XML DC-RDF RDF

Ostali podatki

Sekundarni jezik: Angleški jezik
Sekundarni naslov: The effect of metabolic stress on the lipid droplet proteome of cancer cells
Sekundarni povzetek: Lipid droplets (LD) are newly recognized cytosolic organelles primarily involved in lipid storage. LDs are composed of a neutral lipid core, surrounded by a phospholipid monolayer and proteins. Their number, composition and size are constantly changing according to cellular needs and environmental conditions. LDs have important roles in aggressive cancer cells as they enable their survival in the hypoxic and nutrient poor tumour microenvironment. Many proteins and enzymes with different biological functions are bound to the surface of LDs, embedded within the phospholipid monolayer. Our previous studies have identified an important role of LDs in the cellular stress response to starvation. We assume that the dynamic changes in LD metabolism and function caused by cell stress are accompanied by corresponding alterations in their proteome. In this master thesis we set to explore the nutrient deficiency-induced changes in the LD proteome of aggressive MDA-MB-231 breast cancer cells. Intact LD were isolated from starved and control cells, proteins were extracted, digested to peptides and analysed the latter with mass spectrometry using the label-free quantification approach. In total, we identified 381 proteins associated with the LD fraction, 155 (41 %) of which were classified as contaminants from other cell compartments, while 49 proteins were classified as LD-associated according to previous studies. Among the latter, we detected 15 »bona fide« LD proteins, for which a clear interaction with LDs has already been directly demonstrated in previous studies. Importantly, we detected 177 (47 %) proteins without a known connection to LDs, representing a group of novel, potentially interesting targets for further investigation. We also found that the acute starvation conditions imposed on breast cancer cells had a significant effect on the composition of the LD proteome. Notably, significant change in the amounts of the following 20 LD-associated proteins were detected: G0S2, CDC42, SNX12, CBX3, UBA52, HEBP1, RAC2, AUP1, TBCB, GLRX3, CAST, DBNL, NUCKS1, PTGES3, TXN, PRDX5, TCEAL3, ACSL3, LUC7L2 and HSD17B11. Among these, there are proteins involved in fatty acid, cholesterol and LD metabolism (ACSL3, HSD17B11, HSD17B7, G0S2), ubiquitination (UBA52, AUP1), inflammation (PTGES3), cellular redox homeostasis (TXN, PRDX5), vesicular transport (TRAPPC3, LZTFL1), cytoskeletal organization (TBCB, DBNL) and nuclear function (TCEAL3, NUCKS1). These results suggest that the LD proteome is significantly altered in cancer cells exposed to acute nutrient stress and provide an impetus for future studies on the roles of novel LD-associated proteins in cancer cell metabolism and response to stress.
Sekundarne ključne besede: lipid droplets;stress;starvation;proteome;cancer;fatty acids;
Vrsta dela (COBISS): Magistrsko delo/naloga
Študijski program: 1000377
Konec prepovedi (OpenAIRE): 1970-01-01
Komentar na gradivo: Univ. v Ljubljani, Fak. za kemijo in kemijsko tehnologijo, smer Biokemija
Strani: 52 str.
ID: 12036929