Targeting integrin alpha 5 and focal adhesion kinase to overcome azacitidine resistance in higher risk myelodysplastic syndromes

Myelodysplastic syndromes are typified by bone marrow failure due to profoundly impaired haematopoietic differentiation with higher risk disease commonly progressing to acute myeloid leukaemia. Azacitidine (AZA) and decitabine are the only available therapies for higher risk myelodysplastic syndromes shown to improve the overall survival in these patients. However, primary and secondary resistance results in treatment failure in virtually all patients. Integrin alpha 5 (ITGA5) and integrin signalling have been identified as drivers of primary resistance. I investigated whether combining azacitidine with either an integrin alpha 5 blocking antibody or a focal adhesion kinase inhibitor could overcome azacitidine resistance. After establishing an effective dose of the focal adhesion kinase inhibitor, GSK2256098, I demonstrated that these doses were not toxic to healthy haematopoietic stem and progenitor cells (HSPCs) or bone marrow stromal cells. Using CFU-C assays I show that combining ITGA5 inhibitor or focal adhesion kinase inhibitor with azacitidine could significantly improve the differentiation capacity of AZA resistant HSPCs. To understand the central mechanisms underlying this therapeutic effect several molecular mechanisms were examined. Analysis of functional HSPCs through CFU-C colony genotyping revealed clonal changes were not central to the observed effect. Analysis of LINE-1 methylation showed enhanced demethylation following combination therapy implying increased DNA incorporation of AZA. RNA sequencing analysis indicated combination therapy led to a greater enrichment of an azacitidine specific gene expression signature involving the upregulation of innate inflammatory pathways, platelet aggregation and haemostasis pathways ultimately priming HSPCs for haematopoietic differentiation. Together, my thesis supports the role of inhibiting integrin alpha 5 and focal adhesion kinase to re-sensitise azacitidine resistant HSPCs to azacitidine that could be used as a novel therapeutic approach in higher risk myelodysplastic syndrome.

Grantor dc:publisher

UNSW, Sydney

Year dc:date

2024

Author dc:creator

• Vaughan, Lachlin

• myelodysplastic syndrome
• acute myeloid leukaemia
• chronic myelomonocytic leukaemia
• myeloid neoplasm
• MDS
• CMML
• AML
• azacitidine
• 5-azacytidine
• resistance
• focal adhesion kinase
• integrin
• FAK
• ITGA
• anzsrc-for: 321106 Haematological tumours

Statement dc:rights

• open access
• CC BY 4.0
• free_to_read

Licence

• https://purl.org/coar/access_right/c_abf2
• https://creativecommons.org/licenses/by/4.0/

Language dc:language

en

Identifier

https://doi.org/10.26190/unsworks/30679

OAI identifier oai:identifier

oai:unsworks.library.unsw.edu.au:1959.4/103545