Expression of biomarkers modulating prostate cancer progression: implications in the treatment of the disease

Different predictive values of microvessel density for biochemical recurrence among different PCa populations: A systematic review and meta-analysis

BACKGROUND

Several studies have explored the relationship between intratumoral microvessel density (MVD) and the risk of postoperative biochemical recurrence (BCR) in prostate cancer (PCa), although the results are contradictory. Therefore, we conducted a meta-analysis to investigate the effect of MVD on BCR in PCa.

METHOD

We searched PubMed, MEDLINE, Science Direct/Elsevier, the Cochrane Library, CNKI, and EMBase databases from inception through January 2022, with no year or language restrictions, and used NOS guidelines to evaluate the quality of the 19 eligible studies. The derived hazard ratio (HR) and 95% confidence interval (95%CI) were used to assess each endpoint. Data synthesis was performed with RevMan to assess the prognostic value of MVD in PCa and its heterogeneity, while the publication bias was examined using STATA 16.0.

RESULTS

Our meta-analysis included 19 articles (4 for T1-2, 6 for T1-3, and 9 for T1-4) on postoperative biochemical recurrence of PCa, among which, 3933 patients were pooled. The predictive ability of intratumoral MVD for different stages of PCa on BCR was T1-2 (HR, 2.46; 95% CI, 1.08-5.58; p = 0.03; I²  = 83%), T1-3 (HR, 2.38, 95% CI, 1.41-4.01; p = 0.001; I²  = 82%), T1-4 (HR, 1.61; 95% CI, 1.19-2.19; p = 0.002; I²  = 61%).The subgroup analyses based on European and immunohistochemical antibody none-factor VII were consistent with primary one. Sensitivity analysis excluding those studies judged to be at high risk of bias in T1-2 showed a HR of 2.99[1.70,5.27] (I²  = 38%, p = 0.0001), demonstrating the robustness of risk estimates of MVD for the assessment of biochemical recurrence.

CONCLUSION

Microvessel density is a predictor of BCR among patients with PCa, and earlier T stage PCa with a stronger MVD is associated with BCR. Further studies are needed to investigate neoangiogenesis in different T stages of PCa and whether MVD will be of benefit to the EAU-recommended tool for biochemical recurrence risk assessment.

Inhibition of cyclooxygenase-2-mediated matriptase activation contributes to the suppression of prostate cancer cell motility and metastasis

Chronic inflammation plays an important role in cancer development and progression. Cyclooxygenases-2 (COX-2) is a key enzyme in generating prostaglandins causing inflammation, is often found to be overexpressed in prostate cancer (PCa) and is correlated with PCa cell invasion and metastasis. We aim to investigate the molecular mechanism of how COX-2 promotes PCa cell invasion and metastasis and to evaluate the effect of COX-2 inhibitors in a selected model of PCa progression. Our results showed that the expression of COX-2 and Interleukin 1β (IL-1β) was upregulated in highly invasive PCa cells and was correlated with the activated levels of membrane-anchored serine protease matriptase. The expression levels of COX-2 were increased and were correlated with matriptase levels in PCa specimens. Moreover, results showed that COX-2 overexpression or a COX-2 product Prostaglandin E₂ (PGE₂) caused an increase in matriptase activation and PCa cell invasion, whereas COX-2 silencing antagonized matriptase activation and cell invasion. In addition, the inhibition of COX-2-mediated matriptase activation by Celebrex and sulindac sulfide suppressed the androgen-independent and COX2-overexpressing PCa PC-3 cell invasion, tumor growth and lung metastasis in an orthotopic xenograft model. Our results indicate that COX-2/matriptase signaling contributes to the invasion, tumor growth and metastasis of COX-2-overexpressing and androgen-independent PCa cells.

Lack of Association between COX-2 Staining Level and Biochemical Recurrence Following Salvage Radiation Therapy for Recurrent Prostate Cancer

OBJECTIVE

The ability to predict which men will experience biochemical recurrence (BCR) after salvage radiation therapy (SRT) for recurrent prostate cancer following radical prostatectomy has potential for improvement. Cyclooxygenase-2 (COX-2) overexpression has previously correlated with poor clinical outcomes following primary treatment for prostate cancer, however its predictive ability in the specific setting of SRT has not been examined to date. This study evaluated the association between COX-2 staining intensity and BCR following SRT for recurrent prostate cancer.

METHODS

We utilized a cohort of 151 patients who underwent SRT between July 1987 and July 2003. COX-2 staining intensity in primary tumor samples was detected using monoclonal antibodies and quantified using a computer-assisted method. The association between COX-2 staining intensity and BCR was evaluated using multivariable Cox regression models.

RESULTS

When examining COX-2 staining level as three-level categorical variable (low, moderate, high) based on approximate sample tertiles, there was no evidence of an association with BCR (P=0.18). More specifically, in comparison to patients with low staining intensity, there was no significant difference in risk of BCR for moderate (Relative risk [RR]: 1.17, P=0.56) or high (RR: 0.72, P=0.22) COX-2 staining intensity patients. This lack of association was also observed when considering COX-2 staining intensity as a continuous variable (RR: 0.83, P=0.15).

CONCLUSION

Our results indicate that COX-2 staining intensity is likely of little use in discriminating prognosis of SRT. It appears that the search for prognostic factors associated with BCR should continue elsewhere in order to further enhance patient selection for SRT.

Differential expression of VEGF ligands and receptors in prostate cancer

BACKGROUND

Prostate cancer disseminates to regional lymph nodes, however the molecular mechanisms responsible for lymph node metastasis are poorly understood. The vascular endothelial growth factor (VEGF) ligand and receptor family have been implicated in the growth and spread of prostate cancer via activation of the blood vasculature and lymphatic systems. The purpose of this study was to comprehensively examine the expression pattern of VEGF ligands and receptors in the glandular epithelium, stroma, lymphatic vasculature and blood vessels in prostate cancer.

METHODS

The localization of VEGF-A, VEGF-C, VEGF-D, VEGF receptor (VEGFR)-1, VEGFR-2, and VEGFR-3 was examined in cancerous and adjacent benign prostate tissue from 52 subjects representing various grades of prostate cancer.

RESULTS

Except for VEGFR-2, extensive staining was observed for all ligands and receptors in the prostate specimens. In epithelial cells, VEGF-A and VEGFR-1 expression was higher in tumor tissue compared to benign tissue. VEGF-D and VEGFR-3 expression was significantly higher in benign tissue compared to tumor in the stroma and the endothelium of lymphatic and blood vessels. In addition, the frequency of lymphatic vessels, but not blood vessels, was lower in tumor tissue compared with benign tissue.

CONCLUSIONS

These results suggest that activation of VEGFR-1 by VEGF-A within the carcinoma, and activation of lymphatic endothelial cell VEGFR-3 by VEGF-D within the adjacent benign stroma may be important signaling mechanisms involved in the progression and subsequent metastatic spread of prostate cancer. Thus inhibition of these pathways may contribute to therapeutic strategies for the management of prostate cancer.

The role of treatment modality on the utility of predictive tissue biomarkers in clinical prostate cancer: a systematic review

BACKGROUND

Tissue biomarkers could pivotally improve clinical outcome prediction following prostate cancer therapy. Clinically, prostate cancer is managed by diverse treatment modalities whose individual influence on a biomarker's predictive ability is not well understood and poorly investigated in the literature.

OBJECTIVE

We conducted a systematic review to assess the predictive value of biomarkers in different treatment contexts in prostate cancer.

STUDY METHODOLOGY

A literature search was performed using the MeSH headings "prostate neoplasms" and "biological markers". Rigorous selection criteria identified studies correlating expression with clinical outcomes from primary androgen deprivation therapy (ADT), radical prostatectomy and radiotherapy (± neoadjuvant ADT).

STUDY RESULTS

Of 10,668 studies identified, 481 papers matched initial inclusion criteria. Following rescreening, 384 studies identified 236 individual tissue biomarkers, of which 29 were predictive on multivariate analysis in at least 2 independent cohorts. The majority were only tested in surgical cohorts. Only 8 predictive biomarkers were tested across all 3 treatments with Ki67 identified as universal predictive marker. p16 showed potential for treatment stratification between surgery and radiotherapy but needs further validation in independent studies.

CONCLUSIONS

Despite years of research, very few tissue biomarkers retain predictive value in independent validation across therapy context. Currently, none have conclusive ability to help treatment selection. Future biomarker research should consider the therapy context and use uniform methodology and evaluation criteria.

Assessment of the American Joint Committee on Cancer staging (sixth and seventh editions) for clinically localized prostate cancer treated with external beam radiotherapy and comparison with the National Comprehensive Cancer Network risk-stratification method

BACKGROUND

The objective of this study was to compare the prognostic value of the sixth and seventh editions of the American Joint Cancer Committee (AJCC) Cancer Staging Manual and the risk-stratification model of the National Comprehensive Cancer Network (NCCN).

METHODS

Two-thousand four hundred twenty-nine men who received definitive radiotherapy with or without androgen-deprivation therapy (median follow-up, 74 months) were analyzed.

RESULTS

There was a migration of stage II patients to stage I with AJCC seventh edition (stage I increased from 1% to 38%, and stage II decreased from 91% to 55%). One pair-wise comparison (4%) of Kaplan-Meier estimates of biochemical failure, distant metastasis, prostate cancer-specific survival, and overall survival between stages was statistically significant for the AJCC sixth edition. Conversely, 16 of 24 comparisons (67%) were significant for the AJCC seventh edition. With the NCCN risk-stratification model, 9 of 12 comparisons (75%) were significant. Concordance probability estimate (CPE) and standard error (SE) analysis indicated uniform and significant improvement in the predictive power of the AJCC seventh edition versus the sixth edition for all outcomes. CPE ± SE values for the AJCC seventh edition versus the sixth edition were 0.51 ± 0.009 versus 0.59 ± 0.02, respectively, for biochemical failure; 0.54 ± 0.02 versus 0.70 ± 0.05, respectively, for distant metastasis; 0.57 ± 0.009 versus 0.76 ± 0.007, respectively, for prostate cancer-specific survival; and 0.52 ± 0.006 versus 0.57 ± 0.01, respectively, for overall survival. CPE ± SE values for the NCCN model were 0.59 ± 0.02 for biochemical failure, 0.72 ± 0.05 for distant metastasis, 0.80 ± 0.01 for prostate cancer-specific survival, and 0.57 ± 0.01 for overall survival.

CONCLUSIONS

The current results indicated that the seventh edition of the AJCC Cancer Staging Manual is a major improvement over the sixth edition, because it distributes patients better among the stages and is more prognostic. However, the NCCN model was superior to the AJCC seventh edition and remains the preferred method for risk-based clinical management of prostate cancer with radiotherapy.

The angiogenic switch for vascular endothelial growth factor-A and cyclooxygenase-2 in prostate carcinoma: correlation with microvessel density, androgen receptor content and Gleason grade

OBJECTIVE

Angiogenesis is essential for tumor growth and metastasis; however, angiogenic factors are not uniformly expressed in prostate carcinoma. Our aim was to determine the expression of vascular endothelial growth factor-A (VEGF-A) and cyclooxygenase-2 (COX-2) in prostate carcinomas in relation to intratumoral microvessel density (MVD), tumor grade and androgen receptor (AR) status.

MATERIALS AND METHODS

The expression of AR, VEGF-A and COX-2 was immunohistochemically evaluated in 24 benign prostatic hyperplasia (BPH) and 139 prostate carcinoma cases. MVD was evaluated by CD34 immunostaining.

RESULTS

Nuclear AR expression was inversely related to tumor grade (p < 0.001). MVD was strongly related to tumor grade, VEGF-A and COX-2 (p < 0.001 in all comparisons). VEGF-A expression increased with tumor grade (p < 0.01) and was inversely related to stromal AR expression. COX-2 was present in both BPH and prostate carcinoma, but its expression increased with tumor grade (p < 0.01). High-grade neoplasms presented low-to-moderate VEGF staining intensity compared to strong COX-2 expression.

CONCLUSIONS

Both VEGF-A and COX-2 expression is positively correlated with tumor grade and MVD. However, in Gleason 8-10 tumors, VEGF expression is moderate while COX-2 immunostaining is intense, suggesting a possible switch in the role of these two angiogenic factors in poorly differentiated neoplasms.

ADAMTS1 alters blood vessel morphology and TSP1 levels in LNCaP and LNCaP-19 prostate tumors

Background

Decreased expression of the angiogenesis inhibitor ADAMTS1 (ADAM metallopeptidase with thrombospondin type 1 motif, 1) has previously been reported during prostate cancer progression. The aim of this study was to investigate the function of ADAMTS1 in prostate tumors.

Methods

ADAMTS1 was downregulated by shRNA technology in the human prostate cancer cell line LNCaP (androgen-dependent), originally expressing ADAMTS1, and was upregulated by transfection in its subline LNCaP-19 (androgen-independent), expressing low levels of ADAMTS1. Cells were implanted subcutaneously in nude mice and tumor growth, microvessel density (MVD), blood vessel morphology, pericyte coverage and thrombospondin 1 (TSP1) were studied in the tumor xenografts.

Results

Modified expression of ADAMTS1 resulted in altered blood vessel morphology in the tumors. Low expression levels of ADAMTS1 were associated with small diameter blood vessels both in LNCaP and LNCaP-19 tumors, while high levels of ADAMTS1 were associated with larger vessels. In addition, TSP1 levels in the tumor xenografts were inversely related to ADAMTS1 expression. MVD and pericyte coverage were not affected. Moreover, upregulation of ADAMTS1 inhibited tumor growth of LNCaP-19, as evidenced by delayed tumor establishment. In contrast, downregulation of ADAMTS1 in LNCaP resulted in reduced tumor growth rate.

Conclusions

The present study demonstrates that ADAMTS1 is an important regulatory factor of angiogenesis and tumor growth in prostate tumors, where modified ADAMTS1 expression resulted in markedly changed blood vessel morphology, possibly related to altered TSP1 levels.

ADAMTS1, a putative anti-angiogenic factor, is decreased in human prostate cancer

OBJECTIVE

To investigate the expression of 'ADAM metallopeptidase with thrombospondin type I motif, 1' (ADAMTS1) in human prostate cancer, and to study its relationship to microvessel density (MVD) and metastasis. ADAMTS1 has been described as an anti-angiogenic and antitumour factor, but its function in prostate cancer is unknown.

PATIENTS AND METHODS

ADAMTS1 expression was evaluated by immunohistochemistry in specimens obtained by transurethral resection of the prostate from patients with hormone-naïve and hormone-refractory prostate tumours, including adjacent benign tissue. A semiquantitative scoring system was used for evaluating the staining. MVD was quantified by counting the number of CD34-positive blood vessels.

RESULTS

ADAMTS1 was strongly expressed in the luminal epithelial cells in benign prostate glands, whereas expression was significantly lower in prostate cancer cells. There was no obvious difference between hormone-naïve and hormone-refractory tumours, and ADAMTS1 expression did not correlate with Gleason score. However, in hormone-refractory tumours from patients with metastatic disease, the expression of ADAMTS1 was significantly lower than in tumours from patients without metastases. Furthermore, the MVD was higher in hormone-refractory than in hormone-naïve tumours and benign tissue, and MVD correlated with Gleason score. There was no association between ADAMTS1 and MVD in the hormone-naïve tumours, while hormone-refractory tumours with low ADAMTS1 expression had a higher MVD than those with moderate/high expression.

CONCLUSION

ADAMTS1 expression is decreased in prostate cancer, and might be involved in the early steps of prostate cancer development. Further, ADAMTS1 might have an anti-angiogenic and antimetastatic role in hormone-refractory prostate cancer, where low ADAMTS1 expression is associated with a high MVD and metastasis.

PGE2 and LTB4 tissue levels in benign and cancerous prostates

PGE2 and LTB4 are involved in inflammation and carcinogenesis in several tissues but have not been studied in prostate cancer and hyperplasia until now. We therefore measured PGE2 and LTB4 productions in a total of 206 prostate tissues from 116 patients including benign hyperplastic (90), pericancerous (106) and cancerous samples (10). We also analysed the influence of inflammation levels, prostate volume and glandular to epithelial ratio. PGE2 and LTB4 concentrations were measured using specific enzyme immunoassay kits. There was a correlation between PGE2 level, prostatic volume, inflammation score, and decreased glandular surface. By contrast, there was no correlation between LTB4 levels and inflammation or PGE2 production. Cancerous samples had higher LTB4 levels than pericancerous samples, but there was no difference in PGE2 levels. PGE2 and inflammation may be associated to stromal benign prostatic hyperplasia whereas LTB4 may play a role in prostate carcinogenesis.

Post-treatment prostate biopsies in the era of three-dimensional conformal radiotherapy: what can they teach us?

BACKGROUND

The ability to discriminate between therapeutic success and failure after radiotherapy (RT) for prostate cancer (PCa) remains a clinical challenge. Post-treatment biopsies would seem ideal for evaluating innovations such as dose escalation protocols or combination treatments involving brachytherapy or hormones.

OBJECTIVE

Correlate post-treatment biopsy results with prostate-specific antigen (PSA) and clinical outcome in PCa patients treated with three-dimensional conformal radiotherapy (3DCRT) in a dose-escalation study.

DESIGN, SETTING, AND PARTICIPANTS

This study included 160 patients with clinical stage T1c to T3b PCa treated between 1995 and 2005 in Hospital Universitario la Princesa with 3DCRT who consented to and underwent a transrectal ultrasound (TRUS)-guided prostate biopsy 24-36 mo after RT. The median follow-up was 78 mo (range 27-171 mo).

INTERVENTION

The median radiation dose was 74 gray (Gy; range 66.0-84.1). Risk-adapted short-term androgen deprivation (STAD) and long-term androgen deprivation (LTAD) were associated in 25 and 106 patients, respectively. Right and left systematic biopsies were carried out by the same urologist and were examined by a genitourinary pathologist.

MEASUREMENTS

Biochemical disease-free survival (bDFS) according to American Society for Therapeutic Radiology and Oncology (ASTRO) 1997 and Phoenix definition criteria as well as histologic control using post-treatment prostate biopsies.

RESULTS

Twenty-one percent of patients (34 of 160) had post-treatment-positive biopsies (PB). The 5-yr bDFS according to the Phoenix definition was 87%, 65%, and 92% for the whole series (PB and negative biopsies [NB] patients, respectively [p<0.001]). Multivariate analysis showed that biopsy status at 24-36 mo was an independent predictor of bDFS (p<0.0005) and of clinical failure-free survival (p=0.043).

CONCLUSION

The results of the present study show a strong correlation between a post-treatment PB and the 5-yr probability of bDFS, confirming that PSA control can be an adequate surrogate for local control, as assessed by post-treatment biopsies.

Regulation of Cox-2 by cyclic AMP response element binding protein in prostate cancer: potential role for nexrutine

We recently showed that Nexrutine, a Phellodendron amurense bark extract, suppresses proliferation of prostate cancer cell lines and tumor development in the transgenic adenocarcinoma of mouse prostate (TRAMP) model. Our data also indicate that the anti-proliferative effects of Nexrutine are emediated in part by Akt and Cyclic AMP response element binding protein (CREB). Cyclooxygenase (Cox-2), a pro-inflammatory mediator, is a CREB target that induces prostaglandin E(2) (PGE(2)) and suppresses apoptosis. Treatment of LNCaP cells with Nexrutine reduced tumor necrosis factor alpha-induced enzymatic as well as promoter activities of Cox-2. Nexrutine also reduced the expression and promoter activity of Cox-2 in PC-3 cells that express high constitutive levels of Cox-2. Deletion analysis coupled with mutational analysis of the Cox-2 promoter identified CRE as being sufficient for mediating Nexrutine response. Immunohistochemical analysis of human prostate tumors show increased expression of CREB and DNA binding activity in high-grade tumors (three-fold higher in human prostate tumors compared to normal prostate; P = .01). We have identified CREB-mediated activation of Cox-2 as a potential signaling pathway in prostate cancer which can be blocked with a nontoxic, cost-effective dietary supplement like Nexrutine, demonstrating a prospective for development of Nexrutine for prostate cancer management.

COX-2 expression predicts prostate-cancer outcome: analysis of data from the RTOG 92-02 trial

BACKGROUND

COX-2 is overexpressed in some cancers, including prostate cancer; however, little is known about the effect of COX-2 overexpression on outcome in radiation-treated patients with prostate cancer. We aimed to study COX-2 overexpression and outcome in a well-defined cohort of men who received treatment with short-term androgen deprivation (STAD) plus radiotherapy or long-term androgen deprivation (LTAD) plus radiotherapy.

METHODS

Men with prostate cancer who had participated in the Radiation Therapy Oncology Group (RTOG) 92-02 trial and for whom sufficient diagnostic tissue was available for immunohistochemical staining and image analysis of COX-2 expression were enrolled in this study. Patients in the 92-02 trial had been randomly assigned to treatment with STAD plus radiotherapy or LTAD plus radiotherapy. Multivariate analyses by Cox proportional hazards models were done to assess whether associations existed between COX-2 staining intensity and the RTOG 92-02 primary endpoints of biochemical failure (assessed by the American Society for Therapeutic Radiology and Oncology [ASTRO] and Phoenix criteria), local failure, distant metastasis, cause-specific mortality, overall mortality, and any failure.

FINDINGS

586 patients with sufficient diagnostic tissue for immunohistochemical staining and image analysis of COX-2 expression were included in this study. In the multivariate analyses, the intensity of COX-2 staining as a continuous covariate was an independent predictor of distant metastasis (hazard ratio [HR] 1.181 [95% CI 1.077-1.295], p=0.0004); biochemical failure by two definitions (ASTRO HR 1.073 [1.018-1.131], p=0.008; Phoenix HR 1.073 [1.014-1.134], p=0.014); and any failure (HR 1.068 [1.015-1.124], p=0.011). The higher the expression of COX-2, the greater the chance of failure. As a dichotomous covariate, COX-2 overexpression seemed to be most discriminating of outcome for those who received STAD compared with those who received LTAD.

INTERPRETATION

To our knowledge, this is the first study to establish an association of COX-2 expression with outcome in patients with prostate cancer who have had radiotherapy. Increasing COX-2 expression was significantly associated with biochemical failure, distant metastasis, and any failure. COX-2 inhibitors might improve patient response to radiotherapy in those treated with or without androgen deprivation. Our findings suggest that LTAD might overcome the effects of COX-2 overexpression. Therefore, COX-2 expression might be useful in selecting patients who need LTAD.

Vasoactive intestinal peptide enhances growth and angiogenesis of human experimental prostate cancer in a xenograft model

We show that vasoactive intestinal peptide (VIP) exerts trophic and proangiogenic activities in experimental prostate cancer in vivo. Nude mice were subcutaneously injected with Matrigel impregnated with LNCaP prostate cancer cells. Cell treatment with 100 nM VIP for 1h before xenograft resulted in increased tumor growth after 8 and, more remarkably, 15 days of injection. The same occurred with the mRNA expression of the main angiogenic factor, vascular endothelial growth factor (VEGF), as shown by real-time RT-PCR quantification. The proangiogenic activity of VIP was further established by showing increases of hemoglobin levels, Masson trichromic staining, and immunohistochemical CD34 staining in tumors excised 15 days after subcutaneous injection of VIP-treated cells as compared to control conditions. All these parameters indicate that VIP increases vessel formation. This xenograft model is a useful tool to study in vivo the effects of VIP-related peptides in tumor growth and development of blood supply as well as their therapeutical potential in prostate cancer.

The VIOXX in Prostate Cancer Prevention study: cardiovascular events observed in the rofecoxib 25 mg and placebo treatment groups

BACKGROUND

A double-blind, randomized, placebo-controlled study was designed to determine the cumulative incidence of developing prostate cancer over 6 years of treatment with rofecoxib 25 mg/day versus placebo. Before completion, this trial was terminated following the voluntary withdrawal of rofecoxib. (On September 30, 2004, Merck & Co., Inc. announced the voluntary worldwide withdrawal of rofecoxib from the market.) Here we report the cardiovascular (CV) safety data collected from this study.

METHODS

A total of 4741 men (44-81 years old) exhibiting prostate-specific antigen levels (PSA) between 2.5 and 10 ng/mL were enrolled. Patients were stratified by PSA level and use of low-dose aspirin (LDA), then randomized to rofecoxib 25 mg (n = 2369) or placebo (n = 2372). Safety data were analyzed in all patients receiving > or = 1 dose of study medication. All reported thrombotic CV events occurring on-treatment or within 14 days after study drug discontinuation were adjudicated by an independent panel of clinical experts blinded to treatment assignment. Rates per 100 patient-years and relative risk (RR) of thrombotic CV events, rofecoxib vs. placebo, were determined.

RESULTS

Approximately 36% of patients had > or = 2 CV risk factors or LDA indicated. Median treatment duration was 4.14 (range: 0.03-15.90) months. Twenty-nine patients (14 rofecoxib, rate 1.27; 15 placebo, rate 1.36) experienced confirmed thrombotic CV events; RR 0.94 (95% CI: 0.45, 1.94) vs. placebo. Four patients (one rofecoxib; three placebo) died due to a confirmed thrombotic event. Significantly (p = 0.002) more patients receiving rofecoxib (n = 20; 0.8%) experienced hypertension-related adverse events versus placebo (n = 2; 0.1%). There were no cases of congestive heart failure.

CONCLUSIONS

Rofecoxib 25 mg and placebo demonstrated similar risk of thrombotic CV events in this limited dataset.

Vasoactive intestinal peptide induces cyclooxygenase-2 expression through nuclear factor-kappaB in human prostate cell lines Differential time-dependent responses in cancer progression

The effect of vasoactive intestinal peptide (VIP) on cyclooxygenase-2 (COX-2) expression was analyzed in human prostate non-neoplastic (RWPE-1) as well as cancer androgen-dependent (LNCaP) and independent (PC3) cells. The three cell lines expressed VIP mRNA and VIP peptide, as measured by RT-PCR and immunochemistry, which supports an autocrine/paracrine action of VIP in the prostate gland. VIP levels were progressively higher from non-neoplastic to androgen-dependent and independent cells. Real-time RT-PCR and Western-blotting showed that VIP stimulated both COX-2 mRNA and protein expression in a faster manner as prostate cancer stage progressed (i.e. RWPE1<LNCaP<PC3 cells). Furthermore, VIP induced higher levels of COX-2 protein expression in cancer cells as compared with non-neoplastic cells. The anti-inflammatory agent curcumin blocked VIP-induced COX-2 expression in all cell lines studied supporting the involvement of nuclear factor-kappaB (NFkappaB) in such a response. In fact, VIP increased the translocation of the NFkappaB p50 subunit to the nucleus and the binding of the active form to its target gene promoter, as measured by Western-blotting and ELISA, respectively. VIP provoked faster responses according to the most aggressive status in cancer progression (androgen-independent situation). These results together with the existence of two NFkappaB sites in the COX-2 gene promoter together suggest that COX-2 may be a target for VIP in prostate cancer progression. On the other hand, VIP could be a proinflammatory cytokine acting through the NFkappaB/COX-2 system.

An inverse relation between COX-2 and E-cadherin expression correlates with aggressive histologic features in prostate cancer

The identification of biomarkers in prostatic carcinoma has yielded important data regarding prognosis and has aided in increasing diagnostic accuracy. Additionally, this approach has yielded important insights into the biology of prostatic carcinoma. In this study, we report that the expression of the cyclooxygenase isoenzyme, COX-2, is significantly increased in prostatic carcinoma, whereas that of the cell adhesion molecule, E-cadherin, is decreased. The expression of COX-2 was positively correlated with higher tumor stage, and the presence of carcinoma in surgical margins at prostatectomy. Conversely, the expression of E-cadherin was inversely related to these prognostic indicators. Lastly, the expressions of COX-2 and E-cadherin were very strongly and inversely correlated. These results provide important insights into the biologic underpinnings of prostate carcinoma; and further studies into COX-2 expression in prostate core biopsies may show utility in preprostatectomy prognostication. Furthermore, these results may provide a rational basis for therapeutic intervention and chemoprevention with COX-2 inhibitor therapy in prostate carcinoma.

Molecular markers in the diagnosis of prostate cancer

The genetic alterations leading to prostate cancer are gradually being discovered. A wide variety of genes have been associated with prostate cancer development as well as tumor progression. Knowledge of gene polymorphisms associated with disease aid in the understanding of important pathways involved in this process and may result in the near future in clinical applications. Urinary molecular markers will soon be available to aid in the decision of repeat prostate biopsies. Recent findings suggest the importance of androgen signaling in disease development and progression. The further understanding of interaction of inflammation, diet, and genetic predisposition will improve risk stratification in the near future.

Bcl-2 and bax expression and prostate cancer outcome in men treated with radiotherapy in Radiation Therapy Oncology Group protocol 86-10

PURPOSE

Bcl-2 and bax are proteins with opposing roles in apoptosis regulation; yet abnormal expression of either has been associated with failure after radiotherapy (RT). In this study we examined bcl-2 and bax expression as predictive markers in men treated with radiotherapy +/- androgen deprivation on Radiation Therapy Oncology Group (RTOG) protocol 86-10.

EXPERIMENTAL DESIGN

Suitable archival diagnostic tissue was obtained from 119 (26%) patients for bcl-2 analysis and 104 (23%) patients for bax analysis. Cox proportional hazards multivariate analysis was used to determine the relationship of abnormal bcl-2 and bax expression to the end points of local failure, distant metastasis, cause-specific mortality, and overall mortality. Bcl-2 overexpression was classified as any tumor cell cytoplasmic staining and altered bax expression was classified as greater or lesser cytoplasmic staining intensity of tumor cells as compared with adjacent normal prostate epithelium.

RESULTS

The study cohort exhibited bcl-2 overexpression in 26% (n = 30) of cases and abnormal bax expression in 47% (n = 49) of cases. A borderline significant relationship was observed between abnormal bax expression and higher Gleason score (p = 0.08). In univariate and multivariate analyses, there was no statistically significant relationship seen between abnormal bcl-2 or bax expression and outcome.

CONCLUSIONS

Abnormal bcl-2 and bax expression were not related to any of the end points tested. The cohort examined was comprised of patients with locally advanced disease and it is possible that these markers may be of greater value in men with earlier-stage prostate cancer.

Cyclooxygenase-2 (cox-2) expression is an independent predictor of prostate cancer recurrence

Lack of reliable prognostic markers hinders accurate prediction of disease progression in prostate cancer. The inducible proinflammatory enzyme cyclooxygenase-2 (COX-2) is implicated in prostate carcinogenesis, but its role in cancer progression is less clear. We examined whether COX-2 expression evaluated by immunohistochemistry (IHC) in radical prostatectomy (RP) specimens can predict biochemical recurrence. Archival prostate cancer specimens (n = 60) were obtained from patients who underwent RP, but had not received neoadjuvant hormonal therapy. Twenty-three patients had biochemical or clinical recurrence (mean time of recurrence: 38.2 months), and 37 patients were recurrence free (mean follow-up: 95 months). COX-2 expression was determined by IHC, using an anti-COX-2 antibody. Three individuals scored the staining independently, as high- or low-expression. COX-2 was expressed in prostate cancer cells, in adjacent normal glands and in specimens from patients who later progressed. At 62-months follow-up, COX-2 staining predicted progression with 82.4% sensitivity and 81.3% specificity. Sensitivity (86.4%) and specificity (86.7%) improved at > or = 100-months follow-up. In univariate analysis, Gleason score, preoperative PSA, extraprostatic extension, margin, seminal vesicle invasion, and high COX-2 expression were significant predictors of biochemical recurrence (p < 0.05). In multivariate analysis, preoperative PSA (hazard ratio/unit PSA change 1.080; p = 0.0036) and COX-2 expression (hazard ratio 16.442; p < 0.0001) were independent prognostic indicators. Patients with PSA > 7 ng/ml and high COX-2 expression had the highest probability of recurrence (Kaplan-Meier analysis). COX-2 expression is an independent predictor of prostate cancer progression following RP and underscores the significance of inflammatory factors in this process.