SND1en gainadierazpenaren eragina hepatoma zeluletanlipidoen metabolismoa eta tumoreen garapena

Resumen

SND1 is an evolutionarily conserved multifunctional protein. Although its function has not been fully elucidated yet, is considered a multifunctional protein participating, among others, in mRNA metabolism, gene transcription and lipid metabolism. There is growing evidence of its physiopathological relevance as SND1 expression level has been described to be upregulated in most of the cancer types studied. The objective of this work was to find out whether the alterations in lipid metabolism caused by SND1 have an impact on the proliferation characteristics (growth, adhesion, migration) of cells.With this aim, gene expression analysis, lipid characterization, metabolic labelling assays, gene and protein expression analyses and enzymatic analyses were performed in SND1-overexpressing rat hepatoma cells. On the other hand, these cells were subcutaneously injected to nude mice and the development and composition of xenotumors were analyzed.SND1 overexpression alters cholesterol metabolism by overactivating the SREBP2 regulation system. The uncontrolled cholesterogenesis leads to an accumulation of cholesteryl esters. In addition, alteration in cell morphology and migration are observed and cells overexpressing SND1 show an overexpression of E-cadherin, a cell adhesion molecule dependent on membrane cholesterol composition.Tumors developed after the injection of SND1-overexpressing cells showed a higher growth rate, probably because of the overactivated cholesterogenesis and high E-cadherin expression.Last, alterations of the acylglyceride metabolism have also been observed. SND1 overexpression leads to a low triglyceride content, which seems to be a result of a limited NADPH availability for fatty acid synthesis./SND1 proteina multifuntzionala eta ebolutiboki kontserbatua da. Bere funtzio molekular zehatzaren inguruan eztabaida dagoen arren, lan ezberdinek transkripzio genikoaren erregulazioan, RNAren metabolismoan edo lipidoen metabolismoan parte hartzen duela deskribatu dute. Bere garrantzi fisiopatologikoa aldiz argia da, izan ere minbizi ezberdinetan SND1en adierazpen maila handituta dagoela deskribatu da.Lan honen helburua, SND1ek hepatoma zelulen lipidoen metabolismoan betetzen duen funtzioa eta horrek zelulen ezaugarri morfologikoekin eta proliferatiboekin zerikusirik duen aztertzea izan zen. Horretarako, SND1 modu egonkorrean gainadierazten duten arratoiaren hepatoma zelulak erabili dira, horien lipido konposizioa, gene eta proteina adierazpena, fluxu metabolikoak eta ezaugarri morfologikoak aztertuz. Bestetik, zelula horiek nude saguetan subkutaneoki txertatuz xenotumoreen garapena eta konposizioa ere aztertu dira.SND1en gainadierazpenak kolesterolaren metabolismoaren asaldura eragiten du. SREBP2 kontrol sistema konstitutiboki aktibatuta dago eta zelulek ez dute kolesterogenesia modu egokian kontrolatzen, ondorioz kolesterolaren gainmetaketa gertatzen da kolesteril ester forman. Horrekin batera, zelulen morfologia eta migrazioa aldatuta daude eta E-kadherinaren gainadierazpena gertatzen da; mintz plasmatikoko kolesterol edukiaren menpekoa da adhesio molekulen txertaketa egokia. SND1 gainadierazten duten zelulek hazkuntza tasa altuagoko xenotumoreak sorrarazten dituzte nude saguetan, kolesterogenesi altuagoaren eta E-kadherinaren gainadierazpenaren ondorioz ziurrenik. Azkenik, azilglizeridoen metabolismoaren asaldura ere behatu da, SND1en gainadierazpenak triglizerido eduki baxuagoa eragiten du eta hori gantz-azidoen sintesirako beharrezkoa den NADPH koentzimaren eskuragarritasun baxuaren ondorio dela iradokitzen dute emaitzek. // SND1 is an evolutionarily conserved multifunctional protein. Although its function has not been fully elucidated yet, is considered a multifunctional protein participating, among others, in mRNA metabolism, gene transcription and lipid metabolism. There is growing evidence of its physiopathological relevance as SND1 expression level has been described to be upregulated in most of the cancer types studied. The objective of this work was to find out whether the alterations in lipid metabolism caused by SND1 have an impact on the proliferation characteristics (growth, adhesion, migration) of cells.With this aim, gene expression analysis, lipid characterization, metabolic labelling assays, gene and protein expression analyses and enzymatic analyses were performed in SND1-overexpressing rat hepatoma cells. On the other hand, these cells were subcutaneously injected to nude mice and the development and composition of xenotumors were analyzed.SND1 overexpression alters cholesterol metabolism by overactivating the SREBP2 regulation system. The uncontrolled cholesterogenesis leads to an accumulation of cholesteryl esters. In addition, alteration in cell morphology and migration are observed and cells overexpressing SND1 show an overexpression of E-cadherin, a cell adhesion molecule dependent on membrane cholesterol composition.Tumors developed after the injection of SND1-overexpressing cells showed a higher growth rate, probably because of the overactivated cholesterogenesis and high E-cadherin expression.Last, alterations of the acylglyceride metabolism have also been observed. SND1 overexpression leads to a low triglyceride content, which seems to be a result of a limited NADPH availability for fatty acid synthesis./SND1 proteina multifuntzionala eta ebolutiboki kontserbatua da. Bere funtzio molekular zehatzaren inguruan eztabaida dagoen arren, lan ezberdinek transkripzio genikoaren erregulazioan, RNAren metabolismoan edo lipidoen metabolismoan parte hartzen duela deskribatu dute. Bere garrantzi fisiopatologikoa aldiz argia da, izan ere minbizi ezberdinetan SND1en adierazpen maila handituta dagoela deskribatu da.Lan honen helburua, SND1ek hepatoma zelulen lipidoen metabolismoan betetzen duen funtzioa eta horrek zelulen ezaugarri morfologikoekin eta proliferatiboekin zerikusirik duen aztertzea izan zen. Horretarako, SND1 modu egonkorrean gainadierazten duten arratoiaren hepatoma zelulak erabili dira, horien lipido konposizioa, gene eta proteina adierazpena, fluxu metabolikoak eta ezaugarri morfologikoak aztertuz. Bestetik, zelula horiek nude saguetan subkutaneoki txertatuz xenotumoreen garapena eta konposizioa ere aztertu dira.SND1en gainadierazpenak kolesterolaren metabolismoaren asaldura eragiten du. SREBP2 kontrol sistema konstitutiboki aktibatuta dago eta zelulek ez dute kolesterogenesia modu egokian kontrolatzen, ondorioz kolesterolaren gainmetaketa gertatzen da kolesteril ester forman. Horrekin batera, zelulen morfologia eta migrazioa aldatuta daude eta E-kadherinaren gainadierazpena gertatzen da; mintz plasmatikoko kolesterol edukiaren menpekoa da adhesio molekulen txertaketa egokia. SND1 gainadierazten duten zelulek hazkuntza tasa altuagoko xenotumoreak sorrarazten dituzte nude saguetan, kolesterogenesi altuagoaren eta E-kadherinaren gainadierazpenaren ondorioz ziurrenik. Azkenik, azilglizeridoen metabolismoaren asaldura ere behatu da, SND1en gainadierazpenak triglizerido eduki baxuagoa eragiten du eta hori gantz-azidoen sintesirako beharrezkoa den NADPH koentzimaren eskuragarritasun baxuaren ondorio dela iradokitzen dute emaitzek.