Universität zu Köln

Dolzany de Oliveira, Thaís ORCID: 0000-0002-5503-4051 (2023). Unraveling the Role of Lyn Kinase in the Extracellular Vesicle-Based Crosstalk Between Primary Chronic Lymphocytic Leukemia Cells and Stromal Cells. PhD thesis, Universität zu Köln.

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Abstract

In Chronic Lymphocytic Leukemia (CLL), the tumor cells receive decisive survival support from non-malignant cells within the bone marrow. This support is stimulating tumor growth, progression and helps leukemic cells to evade chemotherapy. Within this microenvironment, the crosstalk between stromal and tumor cells plays an important role. The cell types interact directly and through the paracrine release of intercellular messengers, such as growth factors, and released plasma membrane-enclosed extracellular vesicles (EVs). In particular, the communication by EVs is not fully understood. It has already been shown that members of the Src family of kinases (SFKs) can influence the EV secretion and the SFK member Lyn is aberrantly expressed and highly active CLL-affected tissue, not only on malignant CLL cells but also in macrophages and stromal cells. This thesis aimed to study the mechanism of the Src kinase Lyn in the EV-based communication between the malignant B-CLL and stromal cells. Comparing Lyn proficient and deficient stromal cell lines revealed that the lack of Lyn raised the cell adhesion and podosome formation but decreased the number of filopodia per cell. Moreover, Imaging Flow cytometry and nanoparticle tracking analysis revealed that the EV release and EV uptake are significantly reduced in Lyn deficient stromal cells as compared to wild-type (WT) counterparts, resulting in a 36% reduction of the EV release and a 16% reduction in EV uptake, indicating that Lyn influences both, the cellular release and uptake of EVs. In addition, the same amount (4 μg/ml) of EVs from Lyn proficient stromal cells induced significantly higher support on primary CLL cells as compared to EVs from Lyn deficient counterparts. These data suggest that Lyn not only influences the EV release but also the molecular composition of the EVs. Proteomic comparison of the Lyn proficient and the deficient stromal cell line HS5 highlighted 72 significantly differentially expressed proteins. Among them, CD248 was prominently decreased in Lyn-deficient HS5 cells and a knockdown of CD248 in HS5 cells resulted in a diminished B-CLL cells survival feeding capacity compared to WT cells. In conclusion, the presented data provide initial preclinical evidence, that the tyrosine kinase Lyn crucially influences the EV-based communication between primary B-CLL and supporting bystander cells by raising the EV release and their concentration of functional molecules, such as CD248.

Item Type:	Thesis (PhD thesis)
Translated title:	Title Language Aufdeckung der Rolle von Lyn-Kinase im extrazellulären Vesikel-basierten Kommunikation zwischen primären chronischen lymphatischen Leukämiezellen und Stromazellen German
Creators:	Creators Email ORCID ORCID Put Code Dolzany de Oliveira, Thaís thdolzany2@gmail.com orcid.org/0000-0002-5503-4051 UNSPECIFIED
Contributors:	Contribution Name Email Thesis advisor Hansen, Hinrich P. h.hansen@uni-koeln.de Scientific advisor Hallek, Michael UNSPECIFIED
URN:	urn:nbn:de:hbz:38-734932
DOI:	10.3389/fmed.2022.1059028
Date:	2023
Publisher:	Frontiers in Medicine
Language:	English
Faculty:	Faculty of Mathematics and Natural Sciences
Divisions:	CECAD - Cluster of Excellence Cellular Stress Responses in Aging-Associated Diseases
Subjects:	Natural sciences and mathematics Medical sciences Medicine
Uncontrolled Keywords:	Keywords Language Lyn Kinase English Tumor Microenvironment English Extracellular Vesicles English Chronic Lymphocytic Leukemia (CLL) English Stromal Cells English Filopodia English
Date of oral exam:	23 June 2022
Referee:	Name Academic Title Neundorf, Ines Prof. Dr. Höning, Stefan Prof. Dr. Garcia-Saéz, Ana J. Prof. Dr.
Funders:	DFG
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/73493