Doprema askorbata i njegov učinak na matične stanice osteosarkoma

master's thesis

• Title (english): Delivery and effect of ascorbate on osteosarcoma stem cells
• Author: Lorena Zubaj
• Mentor: Inga Urlić (mentor)
• Committee member: Inga Urlić (predsjednik povjerenstva)
• Committee member: Maja Matulić (član povjerenstva)
• Committee member: Petra Peharec Štefanić (član povjerenstva)
• Committee member: Biljana Balen (član povjerenstva)
• Granter: University of Zagreb; Faculty of Science; (Department of Biology); Zagreb
• Defense date and country: 2022-09-27, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Biology

Abstract

Matične stanice tumora su subpopulacija tumorskih stanica sa sposobnošću samoobnavljanja i velikim
diferencijacijskim potencijalom te se smatra da pokreću inicijaciju i rast tumora. Rezistentnost
matičnih stanica tumora na terapiju glavni je problem u liječenju stoga se intenzivno radi na razvoju
novih terapija koje bi selektivno ciljale matične stanice raka u čemu askorbinska kiselina ima veliki
potencijal. L-askorbinska kiselina jedini je aktivni oblik vitamina C, međutim niska stabilnost
ograničava terapijsku primjenu. Radi povećanja kemijske stabilnosti, stabilniji lipofilni derivati, poput
askorbil palmitata, mogu se pakirati u čvrste lipidne nanočestice te se tako dopremati u stanice. Učinak
askorbata u slobodnom obliku te ugrađenog u čvrste lipidne nanočestice na tumorske i zdrave stanice
ispitali smo testom vijabilnost te mjerenjem unutarstanične razine reaktivnih kisikovih vrsta. Utvrđeno
je kako povećane koncentracije askorbata smanjuju vijabilnost stanica te doprinose porastu razine
reaktivnih kisikovih vrsta što upućuje na prooksidativno djelovanje. Također smo ispitali učinak
optimalnog izvora askorbata na razinu ekspresije proteina GAPDH, ali i na ekspresiju gena markera
diferencijacije matičnih stanica osteosarkoma. Zaključujemo kako askorbat utječe na metabolizam
stanica smanjujući razinu proteina GAPDH čime inhibira proces glikolize uzrokujući energetsku krizu.
Također, askorbat održava matične stanice osteosarkoma na nižem stupnju diferencijacije poticanjem
pojačane ekspresije gena ranih markera diferencijacije dok ekspresija gena kasnog markera
diferencijacije nije detektirana.

Abstract (english)

Cancer stem cells are a subpopulation of tumor cells with the ability of self-renewal and high
differentiation potential and are thought to drive tumor initiation and growth. The resistance of cancer
stem cells to therapy is the main problem in treatment, therefore intensive work is being done on the
development of new therapies that would selectively target cancer stem cells, in which ascorbic acid
has great potential. L-ascorbic acid is the only active form of vitamin C however, its low stability limits
its therapeutic use. In order to increase chemical stability, its more stable lipophilic derivatives such
as ascorbyl palmitate, can be packed into solid lipid nanoparticles and in that way delivered into cells.
We examined the effect of ascorbate in free form and incorporated in solid lipid nanoparticles on tumor
and healthy cells with a viability test and by measuring the intracellular level of reactive oxygen
species. It was found that increased concentrations of ascorbate reduced cell viability and contribute
to an increase in the level of reactive oxygen species, which indicates a pro-oxidative effect. We also
examined the effect of the optimal source of ascorbate on the expression level of GAPDH protein and
on the expression of osteosarcoma stem cell differentiation marker genes. We conclude that ascorbate
affects cell metabolism by reducing the level of GAPDH protein, thus inhibiting the process of
glycolysis, which causes energy crisis. Also, ascorbate maintains osteosarcoma stem cells at a lower
level of differentiation by inducing increased expression of early differentiation markers genes while
expression of late differentiation marker gene was not detected.

• Keywords: askorbat; matične stanice raka; SLN; GAPDH; ROS
• Keywords (english): ascorbate; cancer stem cells; SLN; GAPDH; ROS
• Language: croatian
• URN:NBN: urn:nbn:hr:217:499752
• Study programme: Title: Molecular Biology; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra molekularne biologije (magistar/magistra molekularne biologije)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2022-10-25 11:11:46