2026-09-22T12:09:08Zhttps://helda.helsinki.fi/server/oai/request

oai:helda.helsinki.fi:10138/6331612026-06-09T23:31:36Zcom_10138_18086com_10138_17738col_10138_18088

Yassine, Hassan Helsingin yliopisto, Bio- ja ympäristötieteellinen tiedekunta University of Helsinki, Faculty of Biological and Environmental Sciences Helsingfors universitet, Bio- och miljövetenskapliga fakulteten 2026-06-09T15:23:03Z 2026-06-09T15:22:51Z 2026-06-09 2027-05-04 http://hdl.handle.net/10138/633161 URN:NBN:fi:hulib-202606092831 Metastatic breast cancer is a leading cause of mortality in women worldwide. The key to metastatic progression is the ability of cancer cells to breach the endothelial basement membrane and enter the vasculature. It has long been believed that the process of intravasation is preceded by local invasion, and yet, several studies have detected circulating tumour cells at earlier disease stages. This suggests that intravasation may occur without detectable invasion into the surrounding microenvironment. To investigate this, we developed a vascular labelling strategy that incorporates three components to collectively mark sites of intravasation, allowing for detailed analysis of their molecular and structural characteristics. In this thesis, we validate first the surface expression of two fluorophores, EGFP and mT2. Following surface expression, we show that a recombinant protein moiety binds specifically to EGFP expressed on the surface. Building on this specific cell-surface interaction, we bound the targeting moiety to a large molecular weight dextran that is retained in the vasculature, coupled with fluorescent streptavidin for intravital imaging. Combining these components, we were successful in performing intravital imaging to identify differentially labelled blood vessels, indicating possible intravasation sites. Future work will involve confirmation of the specificity of the labelling approach for sites of intravasation, followed by laser capture microdissection coupled to proteomics for molecular assessment of the changes at these sites of breached vasculature. Importantly, by working with biobanks and clinical collaborators, identified markers of intravasation will be validated against large clinical cohorts to provide actionable therapeutic targets and novel biomarkers for disease stratification, with the central goal of improving patient outcomes from this work. eng Helsingin yliopisto University of Helsinki Helsingfors universitet In Copyright 1.0 breast cancer metastasis intravasation vasculature FLIM Genetiikka ja genomiikka Genetics and genomics Genetik och genomik Genetiikan ja molekulaaristen biotieteiden maisteriohjelma Master's Programme in Genetics and Molecular Biosciences Magisterprogrammet i genetik och molekylära biovetenskaper Identification of intravasation sites for metastatic biomarker development pro gradu -tutkielma master's thesis pro gradu -avhandling restricted