Chemokine Signalling in Malignant Cell Migration

Mills, Shirley (2018) Chemokine Signalling in Malignant Cell Migration. Doctoral thesis, University of East Anglia.

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Communication within and between cells is called signalling; elucidation of cell signalling in diseases, especially metastatic cancers, creates opportunities for developing therapeutic interventions. Signalling initiation occurs when a cell surface receptor binds a ligand; the signal then transmits via phosphorylation events through cytosolic signalling proteins to nuclear or effector proteins that orchestrate a cellular response. G-protein coupled receptors (GPCRs) are one type of receptor; a sub-family of GPCRs are chemokine receptors, their ligands, chemokines, can trigger directional migration. Homeostatic chemokine-triggered migration can be hijacked by cancer cells to facilitate metastasis. This study explored various poorly understood aspects of chemokine signalling that may support metastasis with the aim of identifying therapeutic targets.
Methodology employed THP-1, Jurkat and MCF7 cell-lines, the manipulation of signalling by antagonists, siRNA knockdown or plasmid modification, followed by calcium and chemotaxis assays, protein visualisation using immunofluorescence, flow cytometry and western blot.
Investigations found that in THP-1 cofilin phosphorylation temporally relates to CXCL12-stimulation and to chemotactic migration. In THP-1, but not Jurkat, JAK2 and STAT3 signalling support chemotaxis to CXCL12 and CCL2. Various NSAIDs, Aspirin and Paracetamol drug-specifically influenced chemokine-induced migration and cofilin activity. Rac1, FAK/Pyk2 and Pi3K were found important for chemotaxis to CXC- but not CC-chemokines and to modulate cofilin phosphorylation. Rac1 inhibitor NSC23766 was found to compete with CXCR4 ligands. Many signalling proteins involved in cancer, including GRKs, Src, Raf, MEK, ERK, Cdc42, ROCK, β-catenin and p38MAPK were shown to positively influence chemotactic migration, also Arrestin-2 to support chemotaxis to CXCL12, and Arrestin-3 chemotaxis to CCL3. Dynamin inhibitors and siRNA knockdown produced chemokine, cell type, and dynamin domain-specific responses, Dynamin’s G-domain being important for CXCL12- and PH domain for CCL3-induced migration. PKC’s role in malignancies was found contradictory and isoform specific; PKCε and PKCδ supporting chemotaxis to CXCL12 but not CCL3, whereas PKCα and PKCζ influenced migration to both CXCL12 and CCL3.
This thesis offers novel insights into the complexities of chemokine-induced migration. It examines many key signalling proteins implicated in cancer; reports that NSC23766 offers promise as a lead compound for developing CXCR4 biased antagonists; and offers possible mechanisms, through cofilin phosphorylation and effects on cell migration, for the mixed epidemiology reported for different NSAID’s with respect to their influences on cancer incidence and progression, and suggests Ibuprofen may offer anti-metastatic efficacy.

Item Type: Thesis (Doctoral)
Faculty \ School: Faculty of Science > School of Pharmacy
Depositing User: Megan Ruddock
Date Deposited: 19 Feb 2019 14:45
Last Modified: 19 Feb 2019 14:45


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