Title Ispitivanje mehanizma djelovanja kimernih molekula faktora rasta EGF receptora na signalizaciju u stanici
Title (english) Effects of chimeric EGF receptor growth factor molecules on cell signalling
Author Barbara Nejašmić
Mentor Jasminka Omerović (mentor)
Committee member Vedrana Čikeš Čulić (predsjednik povjerenstva)
Committee member Anita Markotić (član povjerenstva)
Committee member Doris Rušić (član povjerenstva)
Granter University of Split School of Medicine Split
Defense date and country 2024-09-26, Croatia
Scientific / art field, discipline and subdiscipline BIOMEDICINE AND HEALTHCARE Basic Medical Sciences Immunology
Abstract Ciljevi istraživanja: Cilj ovog istraživanja je producirati i ispitati djelovanje dvaju kimernih molekula čimbenika rasta EGF receptora na signalizaciju u stanici, u svrhu kreiranja biološki aktivnih homogenih i heterogenih rekombinantnih molekula dimernih čimbenika rasta koje bi inhibirale aktivnost receptora. U ovom radu pozornost je stavljena na ispitivanje djelovanja homogenih dimernih čimbenika rasta, u obliku fuzijskih proteina, na fosforilaciju EGF receptora i nizvodni RAS/MAPK signalni put u CHO staničnoj liniji. Materijali i metode: Transfektirane stanice CHO stanične linije stimulirane su produciranim kimernim molekulama s pomičnim, odnosno krutim, povezivačem, te je imunoblotom analizirana fosforilacija EGF receptora i nizvodni RAS/MAPK signalni put. Rezultati: Postoji statistički značajna razlika signala fosforilacije receptora i ERK kinaze nizvodno od receptora stimuliranih EGF-om, u odnosu na kimerne molekule 1 i 2. Stimulacijom EGF receptora kimerama 1 i 2, za razliku od stimulacije monomernim čimbenikom rasta, nije zabilježena aktivacija EGF receptora. Potvrđena je hipoteza da postoji mogućnost inhibicije aktivacije receptora kimernom molekulom s krutim povezivačem te je utvrđeno da kimerna molekula s pomičnim povezivačem ima jednak učinak. Unatoč tome što stimulacija receptora kimernim molekulama nije dovela do fosforilacije, rezultati su pokazali aktivaciju nizvodnog RAS/MAPK signalnog puta nakon 5 minuta. Moguće je da kimerne molekule 1 i 2 stupaju u interakciju s receptorom na membrani te uzrokuju aktivaciju RAS/MAPK signalnog puta nepoznatim mehanizmom. Osim toga, odsutstvo fosforilacije ERK kinaze u kasnijim vremenskim intervalima moglo bi se objasniti izostankom endocitoze receptora zbog biofizičkih svojstava strukture povezivača. Rezultati aktivacije mutiranih oblika EGF receptora pokazali su da rekombinantne homodimerne molekule 1 i 2 ne utječu na promjenu trodimenzionalne strukture receptora. Zaključci: Homodimerne rekombinantne molekule 1 i 2 nemaju sposobnost aktivacije EGF receptora ni utjecaj na promjenu njegove trodimenzionalne strukture. Također, utječu na izostanak aktivacije nizvodnih signalnih puteva u stanici. Ako se u konačnici potvrdi vezanje ovih molekula za populaciju EGF receptora na membrani, i izostanak aktivacije ostalih nizvodnih signalnih puteva, rezultati ovog istraživanja postavili bi temelje za razvoj potpuno novog modela inhibicije aktivacije EGF receptora, u osnovi novog oblika tumorske terapije.
Abstract (english) Objectives: The aim is to produce two chimeric EGF receptor growth factor molecules to test their effect on cell signaling, in order to create biologically active homogeneous and heterogeneous recombinant molecules of dimeric growth factors that could potentially inhibit receptor activity. In this study, we focused on examining the effect of homogeneous dimeric growth factors, in the form of fusion proteins, on the phosphorylation of the EGF receptor and the downstream RAS/MAPK signaling pathway in the CHO cell line. Results: The transfected cells of the CHO cell line were stimulated with the produced chimeric molecules containing flexible or rigid linker, followed by immunoblot analysis of the phosphorylation of the EGF receptor and the downstream RAS/MAPK signaling pathway. Materials and methods: A statistically significant result was observed in the difference of phosphorylation signal of the receptor and ERK kinase stimulated by EGF, in relation to chimeric molecules 1 and 2. Stimulation of EGF receptors by chimeras 1 and 2, in contrast to stimulation by monomeric growth factor, did not result in activation of EGF receptors. The hypothesis that there is a possibility of inhibition of receptor activation by a chimeric molecule with rigid linker was confirmed; furthermore it was determined that a chimeric molecule with a flexible linker has the same effect. Despite the fact that receptor stimulation with chimeric molecules did not induce receptor phosphorylation, the results showed activation of the downstream RAS/MAPK signaling pathway after 5 minutes. It is possible that chimeric molecules 1 and 2 interact with the receptor on the membrane and cause the activation of the RAS/MAPK signaling pathway by an unknown mechanism. In addition, the absence of ERK kinase phosphorylation at later time intervals could be interpreted by the absence of receptor endocytosis due to the biophysical properties of the linker structure. The results of the activation of mutated forms of the EGF receptor showed that recombinant homodimeric molecules 1 and 2 do not affect the three-dimensional structure of the receptor. Conclusions: Homodimeric recombinant molecules 1 and 2 do not have the ability to activate the EGF receptor and induce downstream signaling pathways of the cell. Furthermore, they do not cause alterations in the three-dimensional structure of the receptor. If the binding of these molecules to the population of EGF receptors on the membrane, and the absence of activation of other downstream signaling pathways is ultimately confirmed, the results of this study could lay the foundations for the development of a completely new model of inhibition of EGF receptor activation, esentially a new form of tumor treatment.
Keywords
ErbB receptori
EGF receptor
EGF obitelj proteina
kimerne molekule
konformacija
stanična signalizacija
Keywords (english)
ErbB receptors
EGF receptor
EGF family of proteins
chimeric molecules
conformation
cell signalling
Language croatian
URN:NBN urn:nbn:hr:171:276124
Study programme Title: Medicine Study programme type: university Study level: integrated undergraduate and graduate Academic / professional title: doktor/doktorica medicine (doktor/doktorica medicine)
Type of resource Text
File origin Born digital
Access conditions Open access
Terms of use
Created on 2024-09-27 08:00:06