Purpose: Hypoxia regulates key biological processes including angiogenesis via the transcription factor, hypoxia-inducible factor (HIF). In prostate cancer, angiogenesis is also influenced by androgens, and recent cell line studies suggest that this effect is partly mediated by HIF.The study aimed to assess whether a relationship exists in human prostate cancer between expression of the androgen receptor, HIFs, and the key angiogenesis factor, vascular endothelial growth factor (VEGF). Experimental Design: A tissue microarray comprised of 149 radical prostatectomy specimens was constructed. Semiquantitative immunohistochemical analysis was used to assess the expression of the androgen receptor, VEGF and HIF-1a and 2a, and their regulatory prolyl hydroxylase enzymes (PHD1, PHD2, and PHD3). Statistical analysis compared these factors with each other and with prostate-specific antigen relapse.Results: There was a significant correlation between HIF-1a and HIF-2a expression (P = 0.02), and with androgen receptor (P = 0.04 and P < 0.001, respectively) and VEGF expression (P = 0.05 and P <0.001, respectively).VEGF was also significantly related to the androgen receptor (P = 0.05), whereas PHD2 was inversely related to HIF-2a expression. No significant association was shown between HIF-1a or HIF-2a and time to prostate-specific antigen recurrence (P = 0.20 and P = 0.94, respectively). Conclusions: These findings confirm the relationship between hypoxia and the androgen receptor in prostate cancer, and show for the first time, the role of HIF-2a in this disease process. They provide clinical evidence to support the recent cell line findings that androgens may regulateVEGF levels through the activation of HIF in androgen-sensitive tumors. Inhibition of both the HIF pathways may provide new therapeutic options in the management of this disease.One of the key pathways involved in the response to hypoxia is the HIF-1 pathway. HIF-1 is an oxygen-dependent transcriptional activator which is composed of two basic helix-loop-helix PAS proteins, HIF-1a and HIF-1b (1). HIF1b (aryl hydrocarbon nuclear translocator) is constitutively expressed and largely unaffected by oxygen tension in contrast to HIF-1a, which is the responsive HIF-1 element (2). Although three a subunits have been identified, most of the studies to date have concentrated on the role of HIF-1a, with those of HIF-2a and HIF-3a remaining less clear (3).The level and activity of the HIF-1a subunit is tightly regulated through a number of posttranslational modifications. In the presence of oxygen, the prolyl hydroxylase enzymes (PHD1, PHD2, and PHD3) cause site-specific hydroxylation of two proline residues, P402 and P564, within the oxygen-dependent degradation domain of HIF-1a. This hydroxylation allows for the recognition of HIF-1a by the tumor suppressor von Hippel-Lindau protein, an E3 ubiquitin ligase complex, which targets HIF-1a for degradation (4). Hydroxylation of a conserved asparagine residue (Asp 803 ) within the caspase-activated DNase domain ...

Purpose: The aim of this study was to determine the potential of cell-free DNA levels as a diagnostic marker for prostate cancer, having first established the effect that blood sample processing has on this measurement.Experimental Design: A total of 152 blood samples were collected prospectively from patients before their prostate biopsy and 25 from men in two distinct control groups. Blood was processed to yield three components: one-spin plasma (n = 68), two-spin plasma (n = 152), and serum (n = 56) samples.Results: Having established the effect of sample preparation on the measured DNA level, the more reliable two-spin plasma sample was used to determine the relationship between the DNA level and the presence of prostate cancer. Those patients with cancer (n = 78) had a significantly higher level of DNA compared with the control groups (P < 0.0001 and P < 0.0001). However, DNA levels in patients with a benign biopsy (n = 74) were significantly higher than the 78 patients confirmed to have cancer (P = 0.02).Conclusions: We conclude that the sample type used in the quantitation of cell-free DNA has an effect on the level reported. Elevated levels are present in the two-spin plasma samples of patients with prostate cancer compared with healthy controls but are not of diagnostic value during the management of prostate cancer.

These findings suggest that there may be a hormonal and hypoxia independent regulatory mechanism coordinating the expression of HIFs, the AR, and FOXP1 in prostate tumors.

Cell-free DNA has been shown to have diagnostic potential in a number of malignant diseases. Recently, the integrity or size distribution of these fragments has also been identified as having possible diagnostic value. The current study explores the role of this novel parameter in the clinical diagnosis of prostate cancer. Plasma samples, collected prospectively from men undergoing investigation for prostate cancer, were used to obtain a cell-free DNA sample. Real-time PCR was used to quantify the level of cell-free DNA (ng/ml) and its size distribution (delta CD in each case. Sixty-one samples were collected from patients with prostate cancer and 62 from those with benign histology. Analysis failed to reveal a statistically significant relationship between either the level of cell-free DNA (p = 0.82) or its size distribution (p = 0.91) and the presence of cancer. These results demonstrate that cell-free DNA is unlikely to be of diagnostic value in the clinical management of this disease.

These findings suggest that BNIP3 is directly regulated by hypoxia but that there may be a hormonal independent mechanism coordinating the expression of BNIP3 in prostate tumors.