No description available.

No description available.

No description available.

No description available.

This study evaluated comparative genomic hybridisation (CGH) as a tool to detect candidate regions of the genome associated with chemoresistance. Using a variation on conventional CGH, DNA from three cell lines that were resistant to thymidylate synthase (TS) inhibitors (tomudex [TDX] or 5-fluorouracil [5-FU]) and their sensitive parent cells were evaluated. In MCF-7 and H630, cells that were resistant to TDX, a specific TS inhibitor with no other known cytotoxic potential, only a single region of change (18p gain) was apparent. The third cell line H630R10, which was resistant to 5-FU, had changes in several genomic regions following the acquisition of resistance, including 18p. Gain in the chromosomal region containing the TS gene (18pll.32) was detected by CGH in all three resistant cell lines. However, additional novel regions of interest were identified in the cells that were resistant to 5-FU, a cytotoxic agent known to have several other modes of cytotoxicity besides TS inhibition. These results suggested that CGH is of potential use in the detection of regions of the genome involved in chemoresistance. Having shown the potential of CGH as a tool for assessing chemoresistance at the genomic level, steps toward clinical application of this technique were evaluated. A prerequisite for study in archival pathology samples was successful DNA extraction and universal amplification of tumour DNA from paraffin-embedded tumour sections for CGH analysis. Degenerate oligonucleotide primed - polymerase chain reaction (DOP-PCR) was performed on minute quantities (50ngs) of fresh cell line DNA (H630R10) and tumour DNA (osteosarcoma), as well as paraffin-embedded DNA from the same case. The results of these DOP-PCR CGH reactions were compared with conventional CGH using l|0.g quantities of fresh DNA from both H630R10 cell line and osteosarcoma. The CGH profiles of the conventional CGH and DOP-PCR CGH did not show a high level of concordance, only 55% of the gains and 83.3% of losses detected by conventional CGH were detected by DOP-PCR CGH The use of universal amplification by DOP-PCR in paraffin-embedded sections was not taken forward into clinical evaluation. A study of colorectal cancer (CRC) was initiated which involved the microdissection of 29 Dukes' C CRC tumours from fresh frozen material for CGH analysis. This conventional CGH analysis of CRC tumours involved assessing each tumour twice by reversal of fluorochromes. Only genomic regions that were detected as changed in both forward and reverse profiles were accepted. This approach detected several regions of genome as changed across the 29 tumours. In all, 108 gains (a mean number of 3.7 aberrations per tumour, range 1-12) and 85 losses (a mean number of 2.9 aberrations per tumour, range 0-11) were detected in the 29 tumours. CGH analyses identified certain chromosomal regions as more likely to be changed than others. The most frequent aberrations detected across the 29 tumours was a loss of chromosomal arm 18q, seen in 31% of the tumours assessed. Gain was also common at some sites throughout the genome, for example, gain of chromosomal arms, 13q and 20q was seen in 27.6% of cases. Mann-Whitney U tests investigating the association between specific chromosomal aberrations such as gain of 20q or loss of 18q and known markers of CRC tumourigenesis (p53, p27, p21, Rb, cyclin Dl, PCNA, P-catenin, e-cadherin, c-erbB-2, bcl2, EGFR and c-erbB-2) assessed by immunohistochemistry (IHC) in 29 tumours found no association. Testing of the total number of genomic aberrations detected (loss + gain = genetic grade) rather than the frequency of aberration at specific chromosomal loci also found no association with the CRC tumour markers. Finally, the association between the chromosomal aberrations detected by CGH was investigated in relation to patient survival. This thesis has demonstrated the value of a global approach to the study of chemoresistance and tumourigenesis through the application of powerful technology such as CGH.

No description available.

Tumour angiogenesis is a hallmark of cancer. Focal adhesion kinase (FAK) is a non-receptor tyrosine kinase involved in endothelial cells (ECs) survival, proliferation and migration. FAK has several tyrosine phosphorylation sites thought to be involved in FAK function but the requirement of phosphorylation of these residues in vivo is unknown. We have generated mice where endogenous FAK is deleted simultaneously with the expression of nonphosphorylatable FAK-Y397F or FAK-Y861F mutated or wild type forms of FAK in adult endothelium in order to test this. My data show that EC-FAK-Y397FKI mice present with decreased tumour angiogenesis (in sygeneic B16F0, CMT19T and LLC) but impaired B16F0 and CMT19T tumour growth only, with increased tumour hypoxia. FAK-Y397F tumour endothelium is not perfusion, leakage or vascular maturation defective. This mutation affects VEGF-, PlGF- and bFGF-driven angiogenesis in vivo and VEGF+Ang2 administration is able to partially rescue this phenotype ex vivo. In contrast, endothelial FAK-Y861F mutation leads to an initial delay in B16F0 tumour angiogenesis, that subsequently resolves, and does not affect B16F0 tumour growth. LLC and CMT19T tumour growth and angiogenesis are not affected by the endothelial FAK-Y861F mutation; neither are tumour blood vessel perfusion, leakage, vascular maturation or tumour hypoxia. VEGF-, PlGFand bFGF-driven angiogenesis in vivo and ex vivo was not affected by the endothelial FAK-Y861F mutation, whereas increased in vivo angiogenesis was triggered by Ang2 administration. Lastly, to understand whether cytokine profiles that might affect angiocrine signalling are affected differentially in FAK-Y397F vs FAK-Y861F endothelial cells, I show that CCL1 and CCL2 are increased in FAK-Y397F but IL- 13, IL-1F3, CCL4, IL-1F1, CCL2 and others are increased in FAK-Y861F endothelial cells. Overall my data indicates that endothelial-specific FAK mutations on two phosphorylation sites has different effects on tumour angiogenesis, tumour growth, growth factor stimulated angiogenesis in vivo and ex-vivo and cytokine production.

Galectin-3 is a β-galactoside binding lectin expressed in tumour cells and macrophages and has been associated with increased malignancy in a variety of cancers. Previous work has shown that galectin-3 is an important regulator of macrophage function, promoting an alternative (M2) phenotype which potentiates chronic inflammation and fibrosis. Tumour associated macrophages (TAMs) adopt an M2 phenotype and are thought to promote tumour growth by down regulating T cell effector function and promoting angiogenesis. This project examines the hypothesis that host galectin-3 promotes lung cancer growth and spread. In order to test this hypothesis, Lewis Lung Carcinoma tumour growth and metastasis was investigated in strain matched mice either expressing or deficient in galectin-3. The Lewis Lung Carcinoma cell line (LLC1) is a spontaneous lung carcinoma line, derived from C57BL/6 mice, which readily forms tumours when transplanted. Furthermore, LLC1 cells were stably transfected with a Luciferase expressing vector in order to assist detection of tumour growth and metastasis in vivo. An orthotopic model of LLC1 growth suggested that galectin-3-/- animals do not support lung carcinoma growth and spread. This finding was confirmed by a subcutaneous model of cancer growth, where it was found that wild type animals display a higher proportion of macrophages expressing a prototypic M2 marker around tumour sites compared to galectin-3-/- animals. M2-promoting cytokine transcripts were also reduced in galectin-3-/- mice. Additionally, tumours of wild type mice were more invasive and presented more mature blood vessels compared to galectin-3-/- mice. To specifically address the role of recruited cells on tumour growth, metastasis and the inflammation profile around tumour sites, in relation to galectin-3 expression, bone marrow cells (BMCs) were transplanted from wild type to galectin-3-/- mice and vice versa. It was shown that galectin-3 positive BMCs restore the wild type phenotype of tumour growth in galectin-3-/- mice, while galectin-3 deficient BMCs impair tumour growth in wild type animals. Furthermore, macrophage ablation experiments demonstrated incapacity for tumour establishment in the absence of macrophages. A series of experiments investigating reported inhibition of galectin-3 by modified citrus pectin (MCP) via competitive inhibition did not provide conclusive results. MCP had no effect in vivo, but was able to inhibit LLC1 cell growth in vitro. Most importantly though, results were inconclusive as to whether galectin-3 binds MCP. Some ligand displacement was seen, but direct binding of the molecules could not be shown. In general, the results obtained demonstrate a strong pro-tumoural effect of galectin-3 on growth, tissue invasion and metastasis of LLC1 tumours via an increased proportion of Ym1-expressing macrophages around tumour sites. It was shown that macrophages are key cells for tumour initiation and that BMC phenotype in relation to galectin-3 expression determines the phenotype of tumour development in subcutaneous and orthotopic LLC1 models. Therefore, galectin-3 has a strong regulatory effect on tumour phenotype and could present a key target in the management of lung carcinomas.

No description available.

Alterations to the tumour microenvironment is a common feature of many cancers, including breast cancer, and there is increasing evidence that alterations to the microenvironment, including; increased integrin expression, ECM deposition and protease activity, promote cancer progression. Most invasive breast cancers arise from a preinvasive stage, ductal carcinoma in situ (DCIS). Previous work in our laboratory has shown the microenvironment of DCIS is altered, such that myoepithelial cells (MECs) switch to a tumour-promoting phenotype, associated with upregulation of integrin αvβ6 and fibronectin (FN) expression. Mechanisms by which integrin αvβ6 and FN expression are regulated is unclear. We show DCIS progression into invasion is accompanied by an increase in MEC expression of integrin αvβ6 and periductal FN deposition, and their expression were associated in DCIS. These findings were modelled in isolated primary DCIS-MECs, primary normal MECs and MEC lines, with and without integrin αvβ6 expression, where integrin αvβ6-positive MECs upregulating FN expression. We identified integrin αvβ6-positive DCIS ducts were larger than integrin αvβ6-negative DCIS ducts, and mechanical stretching of primary normal MECs and a normal MEC line led to upregulation of integrin αvβ6 expression and FN deposition in a TGFβ-dependent manner. We further show upregulation of integrin αvβ6 and FN by MECs mediate TGFβ-dependent upregulation of MMP13 which promotes breast cancer cell invasion in vitro. These data show altered tissue mechanics in DCIS and MEC expression of integrin αvβ6 and FN deposition are linked, and implicate TGFβ in their activation. These findings suggest integrin αvβ6 and FN may be used as markers to stratify DCIS patients.