| dc.description.abstract | Hypoxia-inducible genes have been linked to the aggressive phenotype of
cancer. However, nearly all work on hypoxia-regulated genes has been
conducted in vitro on cell lines. Here the hypoxia transcriptome in primary
human bladder cancer was investigated using cIDNA microarrays to compare
genes induced by hypoxia in vitro in bladder cancer cell line EJ28 with genes
upregulated on an in vivo array of 39 bladder tumours (27 Ta/T1 12 T2-T4).
mRNA array fold-changes were correlated with carbonic anhydrase IX (CA IX)
staining and necrosis of tumours as surrogate markers of hypoxia. Of 6000
genes 32 were repeatedly hypoxia-inducible in vitro more than 2-fold, five of
which were novel, including lactate transporter SLC16A3 and RNAse 4. Eight
of 32 hypoxia-inducible genes in vitro were also upregulated on the vivo array.
Vascular endothelial growth factor (VEGF) mRNA was upregulated 2-fold by
hypoxia and 2 to 18-fold in 31/39 tumours. Also up regulated on both arrays
was GLUT 1 mRNA, and fold changes on the in vivo genearray significantly
correlated with CA IX staining of tumours (p=0.008). However Insulin-like
growth factor binding protein 3 (IGFBP-3) mRNA was the most strongly
differentially expressed gene in both arrays and its upregulation was confirmed
in the urine of bladder cancer patients (n=157, p<0.01) and in cell line
supernatants. Angiogenin was also upregulated in urine of bladder cancer
patients. Selected genes upregulated by hypoxia (HIF la, HIF 2a, CA IX and
NIP3) were studied by immunohistochemistry for their prognostic significance
and association with necrosis in 98 cystectomy specimens. Normal human
urothelial cells were also grown in culture and a hypoxia genearray profile
compared with EJ28, peripheral blood monocytes and T-cells. This thesis
studies the prevalence of hypoxia and necrosis in bladder cancer, its
relationship with prognosis, genes associated with the hypoxic phenotype and
hypoxia related molecular pathways. | en_US |
