Acute hypoxia increases the aggressive characteristics and survival properties of prostate cancer cells.

BACKGROUND: Androgen withdrawal, the standard therapeutic strategy for advanced prostate cancer, induces a rapid reduction of blood flow to prostate and prostate cancer tissues and the concomitant onset of a hypoxic environment in these tissues. To establish whether hypoxia-responsiveness (by means of the action of hypoxia inducible factor [HIF] -1alpha protein) might affect the tumorigenic or survival properties of prostate cancer cells, we studied how acute exposure of cultured human prostate cancer cells (LNCaP cell line) to hypoxia might alter their pattern of gene expression and their in vitro behavior. METHODS: LNCaP cultures were placed in a hypoxia chamber for up to 24 hr and were compared with control (normoxic) cells for the expression of gene products by Western blotting and semiquantitative reverse transcription-polymerase chain reaction techniques. RESULTS: Exposure of LNCaP cells to acute hypoxia activated a typical cellular hypoxia response characterized by up-regulation of HIF-1alpha and vascular endothelial growth factor protein expression. In contrast, expression of differentiation-specific proteins (prostate specific antigen and androgen receptor) or proliferative-regulatory proteins (c-myc, cyclin D1, p27) were down-regulated by hypoxia. Some of these latter changes (reduction of c-myc and cyclin D expression) were not accompanied by corresponding reduction of mRNAs and were abrogated by a proteosome inhibitor (MG132), suggesting that their loss was associated with their increased degradation rather than through transcriptional controls. The phosphorylation of Akt/protein kinase B and its downstream target, forkhead protein, was highly up-regulated by hypoxia, and cells exposed to transient periods of hypoxia became significantly less sensitive to an apoptotic stimulus (exposure to phorbol ester) when compared with normoxic cells. CONCLUSION: This study demonstrates that even acute hypoxia has the potential to drastically alter the growth, differentiation characteristics, and apoptotic sensitivity of a prostate cancer cell.

Radical prostatectomy by the retropubic, perineal and laparoscopic approach: 12 years of experience in one center.

OBJECTIVES: We retrospectively evaluated the oncological outcome of radical prostatectomy performed by the retropubic, perineal and laparoscopic approaches. METHODS: From 1988 to 2000, 401 patients underwent radical prostatectomy for localized prostate cancer by the retropubic, perineal or laparoscopic approach. Age, clinical stage, preoperative PSA and Gleason score of positive biopsies were noted. Operating time, complication rate, transfusion rate, length of hospital stay, catheterization time and pathological results were reviewed. Kaplan-Meier analysis was used to evaluate the likelihood of biochemical recurrence (PSA > or =0.2 ng/ml). RESULTS: There were no significant differences between the three groups regarding preoperative characteristics, except for PSA (21.4 ng/ml, 13.2 ng/ml, and 11.6 ng/ml for the retropubic, perineal, and laparoscopic approach, p<0.05) and the frequency of stage T1c tumors (31.7%, 47.1% and 63.5%, respectively, p<0.05). The operating time was significantly longer in the laparoscopic approach (285 min) compared to the retropubic and perineal techniques (197 min and 178 min, respectively). The retropubic approach was associated with a higher transfusion rate (26.2% versus 15.9% and 2.9% with the perineal and laparoscopic approaches), longer bladder catheterization time (15.9 days versus 11.7 days and 6.8 days, respectively), and longer hospital stay (15.2 days versus 8.5 days and 7.4 days, respectively) (p<0.05 for each). With the retropubic, perineal and laparoscopic approaches, medical complication rates were 8.3%, 4.2% and 5.1%, and surgical complication rates were 16.5%, 12.7% and 13.1%, respectively. The rates of pathological stage pT2 tumors were 62.1%, 72.2% and 75.9%, in the retropubic, perineal and laparoscopic groups, respectively. Positive surgical margins in pT2 tumors were noted in 19%, 14% and 22%, respectively. The actuarial 3-year recurrence-free survival rates were not significantly different between the three techniques (75%, 85.2% and 84.1%, respectively; 91.7%, 95.8% and 90.4% among patients with organ-confined tumors). CONCLUSION: Despite changes in patient selection criteria over time, and the relatively short follow-up, this study showed no significant difference in oncologic outcome between the retropubic, perineal and laparoscopic approaches to radical prostatectomy.

Hypoxia and an angiogenic response in the partially obstructed rat bladder.

Previous molecular and blood flow studies performed on animal models of partial bladder outlet obstruction (PBOO) caused us to propose that bladder hypoxia/ischemia was a significant effector of the cellular and functional changes that occur in the bladder as a result of this condition. To confirm the occurrence of hypoxia in the partially obstructed bladder, we obtained rat bladders at increasing intervals following PBOO and measured biomarkers of hypoxia (intracellular formation of hypoxyprobe-1 adducts and expression of hypoxia inducible factor-1 alpha [HIF-1 alpha] protein) and whether such hypoxia might elicit an angiogenic response in the tissue. Rats receiving PBOO or controls were treated with hypoxyprobe-1 at increasing intervals subsequent to surgery and their bladders were sectioned and immunostained using an antibody that detects hypoxyprobe-1 adducts. Control rat bladders were unstained, whereas intense, but regionally restricted, hypoxyprobe-1 immunostaining was detected in all obstructed bladders in a unique pattern that changed over time. Proteins were extracted from bladders removed from similarly treated rats and were analyzed for the expression of the HIF-1 alpha protein as well as for expression of angiogenic regulatory factors (vascular endothelial growth factor, angiopoietin-1, and endostatin) using Western blotting techniques. HIF-1 alpha protein was not expressed in control bladders, however, the protein was highly up-regulated over the 2-week period after PBOO. Likewise, the expression of vascular endothelial growth factor (a downstream target of HIF-1 alpha action) and angiopoietin-1 was also up-regulated in obstructed bladders confirming an angiogenic response to this hypoxia. Enigmatically, however, expression of the antiangiogenic molecule endostatin was also up-regulated by chronic PBOO. These results further support the concept that hypoxia is involved in the cellular remodeling as well as in the progressive functional impairment exhibited by the urinary bladder after PBOO.