Localized prostate cancer: radiation or surgery?

Near-Infrared Photoimmunotherapy Targeting Prostate Cancer with Prostate-Specific Membrane Antigen (PSMA) Antibody

Prostate-specific membrane antigen (PSMA) is a membrane protein that is overexpressed manifold in prostate cancer and provides an attractive target for molecular therapy. Near-infrared photoimmunotherapy (NIR-PIT) is a highly selective tumor treatment that employs an antibody-photoabsorber conjugate (APC). Here, we describe the efficacy of NIR-PIT, using a fully human IgG₁ anti-PSMA monoclonal antibody (mAb), conjugated to the photoabsorber, IR700DX, in a PSMA-expressing PC3 prostate cancer cell line. Anti-PSMA-IR700 showed specific binding and cell-specific killing was observed after exposure of the cells to NIR light in vitro In the in vivo study, anti-PSMA-IR700 showed high tumor accumulation and high tumor-background ratio. Tumor-bearing mice were separated into 4 groups: (i) no treatment; (ii) 100 μg of anti-PSMA-IR700 i.v.; (iii) NIR light exposure; (iv) 100 μg of anti-PSMA-IR700 i.v., NIR light exposure was administered. These were performed every week for up to 3 weeks. Tumor growth was significantly inhibited by NIR-PIT treatment compared with the other control groups (P < 0.001), and significantly prolonged survival was achieved (P < 0.0001 vs. other control groups). More than two thirds of tumors were cured with NIR-PIT. In conclusion, the anti-PSMA antibody is suitable as an APC for NIR-PIT. Furthermore, NIR-PIT with the anti-PSMA-IR700 antibody is a promising candidate of the treatment of PSMA-expressing tumors and could be readily translated to humans.Implications: NIR-infrared photoimmunotherapy (NIR-PIT) using a fully human anti-PSMA-IR700 conjugate showed potential therapeutic effects against a PSMA-expressing prostate cancer that is readily translated to humans. Mol Cancer Res; 15(9); 1153-62. ©2017 AACR.

Anti-tumor effects of a recombinant anti-prostate specific membrane antigen immunotoxin against prostate cancer cells

Background

To evaluate anti-prostate cancer effects of a chimeric tumor-targeted killer protein.

Methods

We established a novel fusion gene, immunocasp-3, composed of NH2-terminal leader sequence fused with an anti-prostate-specific membrane antigen (PSMA) antibody (J591), the furin cleavage sequences of diphtheria toxin (Fdt), and the reverse coding sequences of the large and small subunits of caspase-3 (revcaspase-3). The expressing level of the immunocasp-3 gene was evaluated by using the reverse transcription-PCR (RT-PCR) and western blot analysis. Cell viability assay and cytotoxicity assay were used to evaluate its anti-tumor effects in vitro. Apoptosis was confirmed by electron microscopy and Annexin V-FITC staining. The antitumor effects of immunocasp-3 were assessed in nude mice xenograft models containing PSMA-overexpressing LNCaP cells.

Results

This study shows that the immunocasp-3 proteins selectively recognized and induced apoptotic death in PSMA-overexpressing LNCaP cells in vitro, where apoptotic cells were present in 15.3% of the cells transfected with the immunocasp-3 expression vector at 48 h after the transfection, in contrast to 5.5% in the control cells. Moreover, LNCaP cells were significantly killed under the condition of the co-culture of the immunocasp-3-secreting Jurkat cells and more than 50% of the LNCaP cells died when the two cell lines were co-cultured within 5 days. In addition, The expression of immunocasp-3 also significantly suppressed tumor growth and greatly prolonged the animal survival rate in vivo.

Conclusion

A novel fusion gene, immunocasp-3, may represent a viable approach to treating PSMA-positive prostate cancer.

VEGF is associated with the poor survival of patients with prostate cancer: a meta-analysis

Background

Vascular endothelial growth factor (VEGF) is considered as a prime mediator of angiogenesis, and has been implicated in carcinogenesis and metastasis. Various studies examined the relationship between VEGF overexpression with the clinical outcome in patients with prostate cancer, but yielded conflicting results.

Methods

Electronic databases updated to July 2013 were searched to find relevant studies. A meta-analysis was conducted with eligible studies which quantitatively evaluated the relationship between VEGF status and survival of patients with prostate cancer. Survival data were aggregated and quantitatively analyzed.

Results

We performed a meta-analysis of 9 studies that evaluated the correlation between VEGF overexpression and survival in patients with prostate cancer. Combined hazard ratios suggested VEGF overexpression had an unfavorable impact on overall survival (OS) [hazard ratio (HR) =1.54, 95% CI (confidence interval): 1.25-1.83], but not disease free survival (DFS) (HR=1.23, 95% CI: 0.99-1.47) in patients with prostate cancer. No significant heterogeneity was observed among all studies.

Conclusions

VEGF overexpression indicates a poor prognosis for patients with prostate cancer.

Aspidin BB, a phloroglucinol derivative, induces cell cycle arrest and apoptosis in human ovarian HO-8910 cells

Aspidin BB, an effective phloroglucinol derivative from Dryopteris fragrans (L.) Schott, has been previously reported to exert high biological activities. In this study, we analyzed the underlying mechanisms of aspidin BB on human ovarian cancer cell line, HO-8910. Aspidin BB significantly inhibited HO-8910 cell proliferation in a dose- and time-dependent manner. The IC50 values were 15.02, 25.79 and 68.81μM after 72, 48 and 24h treatment, respectively. Meanwhile, aspidin BB markedly induced apoptosis evidenced by characteristic apoptotic morphological changes, nuclear DNA fragmentation, annexin V-FITC/propidium iodide (PI) double staining and S peak. Western blot analysis showed that aspidin BB suppressed Bcl-2 expression and enhanced Bax expression to desintegrate the outer mitochondrial membrane, then caused cytochrome c release which led to the activation of effector caspase-3, and further cleaved the poly ADP-ribose polymerase (PARP) in the nucleus, finally induced cell apoptosis. Furthermore, aspidin BB provoked S phase arrest in HO-8910 cells with up-regulation of pRb, E2F1, CDK2, cyclin E and cyclin A proteins. Taken together, these findings support the conclusion that aspidin BB exhibits cytotoxicity towards human ovarian cancer HO-8910 cells through induction of apoptosis via mitochondrial pathway and arresting cell cycle progression in S phase.

Radiosensitivity of human prostate cancer cells can be modulated by inhibition of 12-lipoxygenase

Nearly 30% of prostate cancer (PCa) patients treated with potentially curative doses relapse at the sites of irradiation. How some tumor cells acquire radioresistance is poorly understood. The platelet-type 12-lipoxygenases (12-LOX)-mediated arachidonic acid metabolism is important in PCa progression. Here we show that 12-LOX confers radioresistance upon PCa cells. Treatment with 12-LOX inhibitors baicalein or BMD122 sensitizes PCa cells to radiation, without radiosensitizing normal cells. 12-LOX inhibitors and radiation, when combined, have super additive or synergistic inhibitory effects on the colony formation of both androgen-dependent LNCaP and androgen-independent PC-3 PCa cells. In vivo, the combination therapy significantly reduced tumor growth.

3p21.3 tumor suppressor gene RBM5 inhibits growth of human prostate cancer PC-3 cells through apoptosis

Background

Recent studies have indicated that the nuclear RNA-binding protein RBM5 has the ability to modulate apoptosis and suppress tumor growth. The aim of this study is to investigate the expression of RBM5 in human prostate cancer and its mechanism of tumor suppression.

Methods

The expression of RBM5 protein in cancerous prostatic tissues and normal tissues was examined by IHC. PC-3 cell line was used to determine the apoptotic function of RBM5 in vitro. PC-3 cells were transiently transfected with pcDNA3.1-RBM5. Cell viability was determined by MTT assay. Rhodamine 123 staining and Annexin V analysis were performed to observe the apoptotic activity of PC-3 cells overexpressing RBM5. Expression of apoptosis-related genes was assessed by western blot.

Results

The expression of RBM5 protein was significantly decreased in cancerous prostatic tissues compared to the normal tissues. PC-3 cells overexpressing RBM5 showed not only significant growth inhibition compared with the vector controls, but also dysfunction of mitochondrial membrane potential and increased apoptotic activity. To further define RBM5 function in apoptotic pathways, we investigated differential expression profiles of various BH3-only proteins including Bid, Bad, and Bim, and apoptosis regulatory proteins include P53, cleaved caspase9, and cleaved caspase3. We found that the expression of both BH3-only proteins and apoptosis regulatory proteins was increased in RBM5 transfected cells.

Conclusion

The expression of RBM5 protein was significantly decreased in cancerous prostatic tissues, which suggests that RBM5 plays an important role in the pathogenesis of prostate cancer. RBM5 may induce the apoptosis of prostate cancer PC-3 cells by modulating the mitochondrial apoptotic pathway, and thus RBM5 might be a promising target for gene therapy on prostate cancer.

Plasma-derived exosomal survivin, a plausible biomarker for early detection of prostate cancer

Background

Survivin is expressed in prostate cancer (PCa), and its downregulation sensitizes PCa cells to chemotherapeutic agents in vitro and in vivo. Small membrane-bound vesicles called exosomes, secreted from the endosomal membrane compartment, contain RNA and protein that they readily transport via exosome internalization into recipient cells. Recent progress has shown that tumor-derived exosomes play multiple roles in tumor growth and metastasis and may produce these functions via immune escape, tumor invasion and angiogenesis. Furthermore, exosome analysis may provide novel biomarkers to diagnose or monitor PCa treatment.

Methods

Exosomes were purified from the plasma and serum from 39 PCa patients, 20 BPH patients, 8 prostate cancer recurrent and 16 healthy controls using ultracentrifugation and their quantities and qualities were quantified and visualized from both the plasma and the purified exosomes using ELISA and Western blotting, respectively.

Results

Survivin was significantly increased in the tumor-derived samples, compared to those from BPH and controls with virtually no difference in the quantity of Survivin detected in exosomes collected from newly diagnosed patients exhibiting low (six) or high (nine) Gleason scores. Exosome Survivin levels were also higher in patients that had relapsed on chemotherapy compared to controls.

Conclusions

These studies demonstrate that Survivin exists in plasma exosomes from both normal, BPH and PCa subjects. The relative amounts of exosomal Survivin in PCa plasma was significantly higher than in those with pre-inflammatory BPH and control plasma. This differential expression of exosomal Survivin was seen with both newly diagnosed and advanced PCa subjects with high or low-grade cancers. Analysis of plasma exosomal Survivin levels may offer a convenient tool for diagnosing or monitoring PCa and may, as it is elevated in low as well as high Gleason scored samples, be used for early detection.

Stromal cell-derived factor-1 and vascular endothelial growth factor as biomarkers for lymph node metastasis and poor cancer-specific survival in prostate cancer patients after radical prostatectomy

OBJECTIVES

This study aims to analyze the clinicopathologic significance of stromal cell-derived factor-1 (SDF-1), vascular endothelial growth factor (VEGF), and matrix metalloproteinase-9 (MMP-9) expression in human prostate cancer (CaP), and their involvement in the prognosis of CaP.

MATERIALS AND METHODS

The expression of SDF-1, VEGF, and MMP-9 were measured using immunohistochemistry in 148 CaP patients who underwent radical prostatectomy for clinically localized disease and in 10 samples of benign prostatic hyperplasia (BPH).

RESULTS

In the CaP group, VEGF and MMP-9 were more strongly expressed in the tumor cells compared with the BPH group. High intensity SDF-1, VEGF, and MMP-9 stains in tumor areas strongly correlated with lymph node metastasis, pathologic stage, and differentiation. Univariate and multivariate analysis showed that SDF-1, VEGF, and lymph node metastasis were independent prognostic factors for prostate cancer-specific survival. High levels of MMP-9, pathologic stage, and differentiation were associated with prostate cancer-specific survival in univariate analysis but the risk estimate was not significant in multivariate analysis.

CONCLUSIONS

High expression levels of SDF-1, VEGF, and MMP-9 are more correlated with lymph node metastatic prostate carcinoma compared with non-lymph-node metastatic cancer. High expression levels of SDF-1 and VEGF strongly predict the biochemical progression in CaP patients after radical prostatectomy.

Saporin toxin-conjugated monoclonal antibody targeting prostate-specific membrane antigen has potent anticancer activity

BACKGROUND

Prostate-specific membrane antigen (PSMA) provides an attractive target for monoclonal antibody targeted therapies in the treatment of prostate cancer (PC). In this study, we generated an immunotoxin by linking a humanized anti-PSMA monoclonal antibody (hJ591) to the ribosome-inactivating protein toxin saporin. The hJ591-saporin immunoconjugate was evaluated for antitumor activity against PC cells.

METHODS

PSMA-positive cell lines, LNCaP and CWR22Rv1 and a PSMA-negative cell line, PC-3, were used in these experiments. The hJ591 was biotinylated and mixed with streptavidin-saporin (SAZAP). The binding ability of hJ591-SAZAP and the extent of internalization into the cells were tested. The viability of cells treated with hJ591-SAZAP was also examined and the apoptotic cells were measured. Lastly, the anticancer effect of hJ591-SAZAP was investigated in vivo.

RESULTS

The binding ability of hJ591-SAZAP to PSMA was equivalent to that of unconjugated J591. Internalization of hJ591-SAZAP was clearly detected in PSMA-positive, but not in PSMA-negative cell lines. IC(50) of hJ591-SAZAP was 0.14 nM, 1.99 nM, and more than 100 nM in LNCaP, CWR22Rv1, and PC-3 cells, respectively. After 72 hr of hJ591-SAZAP treatment, the percentage of apoptotic cells was 60.29% and 40.73% in LNCaP and CWR22Rv1 cells, respectively, compared to 4.70% in PC-3 cells. The hJ591-SAZAP also had anticancer activity in a LNCaP xenograft model.

CONCLUSIONS

Our findings show that hJ591-SAZAP conjugate has potent and selective antitumor effects on PSMA-positive PC cells in vitro and in vivo. This study supports development of PSMA antibody-toxin conjugates for therapy of PC.

Survivin gene silencing sensitizes prostate cancer cells to selenium growth inhibition

Background

Prostate cancer is a leading cause of cancer-related death in men worldwide. Survivin is a member of the inhibitor of apoptosis (IAP) protein family that is expressed in the majority of human tumors including prostate cancer, but is barely detectable in terminally differentiated normal cells. Downregulation of survivin could sensitize prostate cancer cells to chemotherapeutic agents in vitro and in vivo. Selenium is an essential trace element. Several studies have shown that selenium compounds inhibit the growth of prostate cancer cells. The objective of this study is to investigate whether survivin gene silencing in conjunction with selenium treatment could enhance the therapeutic efficacy for prostate cancer and to elucidate the underlying mechanisms.

Methods

Expression of survivin was analyzed in a collection of normal and malignant prostatic tissues by immunohistochemical staining. In vitro studies were conducted in PC-3M, C4-2B, and 22Rv1 prostate cancer cells. The effect of selenium on survivin expression was analyzed by Western blotting and semi-quantitative RT-PCR. Survivin gene knockdown was carried out by transfecting cells with a short hairpin RNA (shRNA) designed against survivin. Cell proliferation was quantitated by the 3-(4,5-Dimethylthiazol-2-yl)- 2,5-Diphenyltetrazolium Bromide (MTT) assay and apoptosis by propidium iodide staining followed by flow cytometry analysis. Finally, in vivo tumor growth assay was performed by establishing PC-3M xenograft in nude mice and monitoring tumor growth following transfection and treatment.

Results

We found that survivin was undetectable in normal prostatic tissues but was highly expressed in prostate cancers. Survivin knockdown or selenium treatment inhibited the growth of prostate cancer cells, but the selenium effect was modest. In contrast to what have been observed in other cell lines, selenium treatment had little or no effect on survivin expression in several androgen-independent prostate cancer cell lines. Survivin knockdown sensitized these cells to selenium growth inhibition and apoptosis induction. In nude mice bearing PC-3M xenografts, survivin knockdown synergizes with selenium in inhibiting tumor growth.

Conclusions

Selenium could inhibit the growth of hormone-refractory prostate cancer cells both in vitro and in vivo, but the effects were modest. The growth inhibition was not mediated by downregulating survivin expression. Survivin silencing greatly enhanced the growth inhibitory effects of selenium.

Potent Antitumor Activity of an Auristatin-Conjugated, Fully Human Monoclonal Antibody to Prostate-Specific Membrane Antigen

Prostate-specific membrane antigen (PSMA) is the prototypic cell-surface marker of prostate cancer and provides an attractive target for monoclonal antibody (mAb) targeted therapies. In this study, a novel antibody-drug conjugate (ADC) was generated by linking a fully human PSMA mAb to monomethylauristatin E (MMAE), a potent inhibitor of tubulin polymerization. The PSMA ADC was evaluated for antitumor activity in vitro and in a mouse xenograft model of androgen-independent human prostate cancer. The PSMA ADC eliminated PSMA-expressing cells with picomolar potency and >700-fold selectivity in culture. When used to treat mice with established human C4-2 tumors, the PSMA ADC significantly improved median survival 9-fold relative to vehicle or isotype-matched ADC (P = 0.0018) without toxicity. Treatment effects were also manifest as significant (P = 0.0068) reduction in serum levels of prostate-specific antigen (PSA). Importantly, 40% of treated animals had no detectable tumor or measurable PSA at day 500 and could be considered cured. The findings support development of PSMA antibody-auristatin conjugates for therapy of prostate cancer.

Complications after cystectomy and urinary diversion in patients previously treated for localized prostate cancer

OBJECTIVES

To assess the morbidity associated with radical cystectomy in patients who had previously undergone definitive treatment of prostate cancer.

METHODS

A retrospective review was undertaken, identifying 35 patients undergoing radical cystectomy with a previous history of radical prostatectomy and/or radiotherapy for prostate cancer. The clinical and surgical information was analyzed to assess patient outcomes. Specific attention was given to the rate, severity, and time course of the postoperative complications. In addition, outcomes after orthotopic and continent cutaneous diversion in this patient cohort were examined.

RESULTS

An overall complication rate of 76% was seen in this patient cohort, with 47% of patients experiencing a complication that presented later than postoperative day 30. Radiotherapy was associated with a slightly greater complication rate compared with radical prostatectomy monotherapy (77% versus 71%). Continent urinary diversion (n = 14) was associated with increased morbidity compared with ileal conduit diversion (n = 21). However, a greater percentage of the complications occurring in patients undergoing ileal conduit diversion were major (80% versus 67%).

CONCLUSIONS

Our experience has suggested that radical cystectomy in patients previously treated for prostate cancer with radiotherapy and/or radical prostatectomy may be associated with a greater level of morbidity than previously reported. This finding may be, in part, because a significant portion of complications present in a delayed fashion and, as such, have not been seen in previous reports with limited follow-up. For this reason, careful consideration of these risks is necessary when counseling this patient cohort regarding the decision to undergo radical cystectomy.

Matrix metalloproteinase inhibitor Ro 28-2653 in combination with estramustine: tumor-reducing effects on hormone-sensitive prostate cancer in rats

Therapeutic efficacy of the novel matrix metalloproteinase (MMP) inhibitor, Ro 28-2653 (5-biphenyl-4-yl-5-[4-(-nitro-phenyl)-piperazin-1-yl]-pyrimidine-2,4,6-trione), has been shown in various models of different tumor entities. The tumor growth-reducing effect has been demonstrated in the orthotopic rat prostate Dunning model (subline MatLyLu). Based on these results we investigated Ro 28-2653 in combination with estramustine on the G subline of the Dunning tumor. This subline is characterized by a low metastatic ability and androgen sensitivity. Efficacy was determined by recording tumor growth in vivo by magnetic resonance imaging (MRI). Tumor cells were injected into the prostates of 81 Copenhagen rats. MRI was performed at day 100 and at day 126 after tumor cell injection. The duration of therapy was 17 days with daily oral application of Ro 28-2653 (100 mg/kg) and four i.p. injections of estramustine (7.5 mg/kg). Histological evaluations were conducted to provide further information about the effects on tumor morphology. Orthotopic tumor induction was successful in 100% of the animals. Tumor volume calculations with MRI showed a significant difference between the control groups, the animals treated with Ro 28-2653, and the animals treated with the combination of Ro 28-2653 and estramustine. The new MMP inhibitor Ro 28-2653 reduces tumor growth and provides a compatible therapeutic alternative for patients with prostate cancer.

Psychological functioning associated with prostate cancer: cross-sectional comparison of patients treated with radiotherapy, brachytherapy, or surgery

This study compared the prevalence of psychological difficulties (i.e., anxiety and depression), psychophysiological problems (i.e., insomnia and fatigue), and sexual difficulties across three modalities of treatment for prostate cancer (radiotherapy, brachytherapy, and radical prostatectomy). A total of 861 men completed a battery of questionnaires assessing anxiety, depression, fatigue, insomnia, and quality of life. Patients who initially received radiotherapy had higher levels of depression, anxiety, and fatigue and a lower quality of life, and were more likely to report clinical levels of depression and fatigue. Patients who initially received surgery were more likely to report clinical levels of sexual difficulties but less likely to report clinical levels of depression and fatigue, while patients who received brachytherapy were less likely to report sexual difficulties. Although cross-sectional, these findings raise the possibility of a differential influence of treatments for prostate cancer on some aspects of psychological functioning.

Methylseleninic acid potentiates apoptosis induced by chemotherapeutic drugs in androgen-independent prostate cancer cells

PURPOSE

To test whether and how selenium enhances the apoptosis potency of selected chemotherapeutic drugs in prostate cancer (PCA) cells.

EXPERIMENTAL DESIGN

DU145 and PC3 human androgen-independent PCA cells were exposed to minimal apoptotic doses of selenium and/or the topoisomerase I inhibitor 7-ethyl-10-hydroxycamptothecin (SN38), the topoisomerase II inhibitor etoposide or the microtubule inhibitor paclitaxel/taxol. Apoptosis was measured by ELISA for histone-associated DNA fragments, by flow cytometric analysis of sub-G(1) fraction, and by immunoblot analysis of cleaved poly(ADP-ribose)polymerase. Pharmacologic inhibitors were used to manipulate caspases and c-Jun-NH(2)-terminal kinases (JNK).

RESULTS

The methylselenol precursor methylseleninic acid (MSeA) increased the apoptosis potency of SN38, etoposide, or paclitaxel by several folds higher than the expected sum of the apoptosis induced by MSeA and each drug alone. The combination treatment did not further enhance JNK1/2 phosphorylation that was induced by each drug in DU145 cells. The JNK inhibitor SP600125 substantially decreased the activation of caspases and apoptosis induced by MSeA combination with SN38 or etoposide and completely blocked these events induced by MSeA/paclitaxel. The caspase-8 inhibitor zIETDfmk completely abolished apoptosis and caspase-9 and caspase-3 cleavage, whereas the caspase-9 inhibitor zLEHDfmk significantly decreased caspase-3 cleavage and apoptosis but had no effect on caspase-8 cleavage. None of these caspase inhibitors abolished JNK1/2 phosphorylation. A JNK-independent suppression of survivin by SN38 and etoposide, but not by paclitaxel, was also observed. In contrast to MSeA, selenite did not show any enhancing effect on the apoptosis induced by these drugs.

CONCLUSIONS

MSeA enhanced apoptosis induced by cancer therapeutic drugs in androgen-independent PCA cells. In DU145 cells, the enhancing effect was primarily through interactions between MSeA and JNK-dependent targets to amplify the caspase-8-initiated activation cascades. The results suggest a novel use of methyl selenium for improving the chemotherapy of PCA.

Dynamic Magnetic Resonance Tomography and Proton Magnetic Resonance Spectroscopy of Prostate Cancers in Rats Treated by Radiotherapy

RATIONALE AND OBJECTIVES

To establish an experimental setting for monitoring perfusion and metabolism in orthotopic prostate cancer at 1.5 T using dynamic contrast-enhanced magnetic resonance imaging (DCE MRI) and 1H-MR spectroscopy (MRS).

METHODS

Dunning rat prostate cancer cells were injected into the prostate by open surgery. Twelve tumor-bearing rats (5 of these irradiated) and 6 healthy controls were followed up using gadolinium-diethylenetriaminepentaacetic acid -enhanced dynamic MRI and 1H-MRS. Amplitude and the exchange rate constant kep were calculated (2-compartment model). From 1H-MR spectra, ratios of choline (Cho) and creatine (tCr) were calculated. All tumors were examined histologically.

RESULTS

On DCE MRI parameter maps, tumors showed increased vascularization. kep and microvessel density were correlated (r = 0.97). Tumors showed elevated Cho/tCr and an unexpected lipid fraction (2.0-2.2 parts per million). Irradiation slowed tumor growth significantly. Changes of perfusion and metabolism could be detected in all tumors during follow up.

CONCLUSION

DCE MRI and 1H-MRS has potential to characterize orthotopic Dunning prostate cancer in rats, which is a promising model similar to human prostate carcinomas.

Inverse association between prostatic polyunsaturated fatty acid and risk of locally advanced prostate carcinoma

BACKGROUND

An effect of fatty acids has been implicated in men with advanced-stage prostate carcinoma and in men who have died of the disease. To evaluate the influence of fatty acids in men with prostate carcinoma at earlier stages, the authors examined the relation between prostatic concentrations of fatty acids and locally advanced prostate carcinoma in men with clinically organ-confined disease.

METHODS

Fatty acids were measured by capillary gas chromatography in fresh, nonmalignant prostate tissue specimens collected during surgery from 196 men undergoing radical prostatectomy for localized prostate carcinoma. Two-sided, two-sample Student t tests compared mean concentrations in men with extraprostatic disease (pT3-4N0-1M0) with control men with organ-confined disease. Logistic regression accounted for clinical stage, prostate-specific antigen level, Gleason sum, and other factors.

RESULTS

Percent total prostatic polyunsaturated fatty acid (PUFA) was found to be inversely associated with risk of locally advanced prostate carcinoma (n=52) (odds ratio [OR]=0.93, 95% confidence interval [95% CI], 0.87-0.99; P=0.035). Risk of seminal vesicle involvement accounted for this association (OR=0.86, 95% CI, 0.78-0.95; P=0.003). Percent omega-3 fatty acid (eicosapentanoic + docosahexanoic acids) and percent arachidonic acid also were found to be inversely related to the risk of seminal vesicle involvement (OR=0.52, 95% CI, 0.30-0.90; P=0.02; and OR=0.84, 95% CI,; 0.75-0.95; P=0.005, respectively).

CONCLUSIONS

Prostatic PUFA levels appear to influence the risk of locally advanced prostate carcinoma in men with clinically organ-confined disease. This association may be mediated through the immune system.