Nuclear Factor-κB Nuclear Localization Is Predictive of Biochemical Recurrence in Patients with Positive Margin Prostate Cancer

Inhibitory effect of roburic acid in combination with docetaxel on human prostate cancer cells

Roburic acid (ROB) is a naturally occurred tetracyclic triterpenoid, and the anticancer activity of this compound has not been reported. Docetaxel (DOC) is the first-line chemotherapeutic agent for advanced stage prostate cancer but toxic side effects and drug resistance limit its clinical success. In this study, the potential synergistic anticancer effect and the underlying mechanisms of ROB in combination with DOC on prostate cancer were investigated. The results showed that ROB and DOC in combination synergistically inhibited the growth of prostate cancer cells. The combination also strongly induced apoptosis, and suppressed cell migration, invasion and sphere formation. Mechanistic study showed that the combined effects of ROB and DOC on prostate cancer cells were associated with inhibition of NF-κB activation, down regulation of Bcl-2 and up regulation of Bax. Knockdown of NF-κB by small interfering RNA (siRNA) significantly decreased the combined effect of ROB and DOC. Moreover, we found that esomeprazole (ESOM), a proton pump inhibitor (PPI), strongly enhanced the effectiveness of ROB and DOC on prostate cancer cells in acidic culture medium. Since acidic micro environment is known to impair the efficacy of current anticancer therapies, ESOM combined with ROB and DOC may be an effective approach for improving the treatment of prostate cancer patients.

Unveiling the m6A Methylation Regulator Links between Prostate Cancer and Periodontitis by Transcriptomic Analysis

Objective

To identify the N6-methyladenosine (m6A) methylation regulator genes linking prostate adenocarcinoma (PRAD) and periodontitis (PD).

Materials and Methods

PD and TCGA-PRAD GEO datasets were downloaded and analyzed through differential expression analysis to determine the differentially expressed genes (DEGs) deregulated in both conditions. Twenty-three m6A RNA methylation-related genes were downloaded in total. The m6A-related genes that overlapped between PRAD and PD were identified as crosstalk genes. Survival analysis was performed on these genes to determine their prognostic values in the overall survival outcomes of prostate cancer. The KEGG pathways were the most significantly enriched by m6A-related crosstalk genes. We also performed lasso regression analysis and univariate survival analysis to identify the most important m6A-related crosstalk genes, and a protein-protein interaction (PPI) network was built from these genes.

Results

Twenty-three m6A methylation-related regulator genes were differentially expressed and deregulated in PRAD and PD. Among these, seven (i.e., ALKBH5, FMR1, IGFBP3, RBM15B, YTHDF1, YTHDF2, and ZC3H13) were identified as m6A-related cross-talk genes. Survival analysis showed that only the FMR1 gene was a prognostic indicator for PRAD. All other genes had no significant influence on the overall survival of patients with PRAD. Lasso regression analysis and univariate survival analysis identified four m6A-related cross-talk genes (i.e., ALKBH5, IGFBP3, RBM15B, and FMR1) that influenced risk levels. A PPI network was constructed from these genes, and 183 genes from this network were significantly enriched in pathogenic Escherichia coli infection, p53 signaling pathway, nucleocytoplasmic transport, and ubiquitin-mediated proteolysis.

Conclusion

Seven m6A methylation-related genes (ALKBH5, FMR1, IGFBP3, RBM15B, YTHDF1, YTHDF2, and ZC3H13) were identified as cross-talk genes between prostate cancer and PD.

Early mRNA Expression of Neuroendocrine Differentiation Signals Predicts Recurrence After Radical Prostatectomy: A Transcriptomic Analysis

Background

Neuroendocrine differentiation (NED) of prostate cancer (PC) is a process that often occurs under evolutionary pressure from pharmacologic blockade of androgen receptor signaling at advanced stages of the disease. Identifying a subset of early PC that has a higher likelihood to evolve into this entity is key for developing therapeutic strategies that could more effectively target this phenotype. This study aimed to assess the prognostic relevance of mRNA expression of major players involved in NED of primary prostate tumors.

Methods

RNA sequencing data from 122 patients with localized PC were analyzed. Transcript levels of key genes involved in NED, with a focus on endothelin axis and nuclear factor kappa B (NF-κB), were assessed and were correlated with time to prostate specific antigen (PSA) recurrence. Copy number alteration of tumor suppressor genes and gene expression of additional signals hallmarking NED was compared between altered and unaltered groups, including lineage determining transcription factors, transcriptional repressors, cell cycle and epigenetic regulators.

Results

The presence of altered mRNA expression using a z-score threshold of 2 in NFKB1, RELA, EDN1, EDNRA, and EDNRB genes was associated with a higher Gleason score (P < 0.001) and a shorter time to biochemical recurrence (BCR) (P = 0.029). There was a significant direct correlation between NFKB1 and RELA (P < 0.001), NFKB1 and EDNRA (P < 0.001), NFKB1 and EDNRB (P < 0.001), EDNRA and EDNRB expression (P < 0.001). ASCL1 (q < 0.001), ONECUT2 (q < 0.001), DLL3 (q = 0.019), AURKA (q = 0.013), AURKB (q = 0.014), PLK1 (q < 0.001), and EZH2 (q < 0.001) were enriched in patients with tumors harboring alterations in endothelin axis and NF-κB subunit genes whereas REST was downregulated (q < 0.001).

Conclusions

This analysis suggests that altered mRNA expression of NF-κB and endothelin axis genes in early PC is not only a harbinger of a more aggressive clinical course but is also associated with aberrant gene expression of several transcription factors, transcriptional repressors, cell cycle and epigenetic regulators that are directly involved in NED, in line with their biological roles. This may have implications for closer follow-up and potential use of targeted therapeutic approaches postoperatively in the adjuvant setting to improve outcomes of these patients.

Growth and differentiation factor 15 and NF-κB expression in benign prostatic biopsies and risk of subsequent prostate cancer detection

Growth and differentiation factor 15 (GDF‐15), also known as macrophage inhibitory cytokine 1 (MIC‐1), may act as both a tumor suppressor and promotor and, by regulating NF‐κB and macrophage signaling, promote early prostate carcinogenesis. To determine whether expression of these two inflammation‐related proteins affect prostate cancer susceptibility, dual immunostaining of benign prostate biopsies for GDF‐15 and NF‐κB was done in a study of 503 case‐control pairs matched on date, age, and race, nested within a historical cohort of 10,478 men. GDF‐15 and NF‐κB expression levels were positively correlated (r = 0.39; p < 0.0001), and both were significantly lower in African American (AA) compared with White men. In adjusted models that included both markers, the odds ratio (OR) for NF‐κB expression was statistically significant, OR =0.87; p = 0.03; 95% confidence interval (CI) =0.77–0.99, while GDF‐15 expression was associated with a nominally increased risk, OR =1.06; p = 0.27; 95% CI =0.96–1.17. When modeling expression levels by quartiles, the highest quartile of NF‐κB expression was associated with almost a fifty percent reduction in prostate cancer risk (OR =0.51; p = 0.03; 95% CI =0.29–0.92). In stratified models, NF‐κB had the strongest negative association with prostate cancer in non‐aggressive cases (p = 0.03), older men (p = 0.03), and in case‐control pairs with longer follow‐up (p = 0.02). Risk associated with GDF‐15 expression was best fit using nonlinear regression modeling where both first (p = 0.02) and second (p = 0.03) order GDF‐15 risk terms were associated with significantly increased risk. This modeling approach also revealed significantly increased risk associated with GDF‐15 expression for subsamples defined by AA race, aggressive disease, younger age, and in case‐control pairs with longer follow‐up. Therefore, although positively correlated in benign prostatic biopsies, NF‐κB and GDF‐15 expression appear to exert opposite effects on risk of prostate tumor development.

A phase II randomized placebo-controlled trial of pomegranate fruit extract in men with localized prostate cancer undergoing active surveillance

INTRODUCTION OR OBJECTIVE

Men with favorable-risk prostate cancer (PCa) on active surveillance may benefit from intervention strategies to slow or prevent disease progression and the need for definitive treatment. Pomegranate and its extracts have shown antiproliferative and proapoptotic effects in cell lines and animal models, but its effect on human prostate cancer as a target tissue remain unclear. Objectives of this trial include pomegranate's ability to alter serum and prostate tissue biomarkers and the ability of an active surveillance cohort to adhere to a chemoprevention trial for 1 year.

METHODS

Men with organ-confined, favorable-risk PCa on AS were randomly assigned to receive pomegranate fruit extract (PFE) 1000 mg (n = 15) or placebo (n = 15) once daily for twelve months. Prostate biopsies were performed at study entry and upon completion of the 1-year intervention. Plasma and urinary biomarkers were analyzed utilizing immunoassays and HPLC. Tissue proteins were assessed by immunohistochemistry (IHC) and measured by automated quantitation.

RESULTS

PFE was well-tolerated with no significant toxicities. One patient withdrew before study initiation and 29 completed the 1-year intervention. No differences in plasma insulin-like growth factor-1 (IGF-1) levels, prostate-specific antigen doubling time, or biopsy kinetics were observed. Metabolites including urolithin A and urolithin A-gluc were detected more frequently in the PFE arm in both urine and plasma (p < .001 and p = .006, respectively). IHC analyses revealed reductions from baseline in 8-OHdG (a DNA damage marker) (p = .01) and androgen receptor expression (p = .04) in prostate tumor associated with PFE treatment.

CONCLUSION

PFE administration for 12-month was well-tolerated and the protocol followed in an active surveillance population. Analyses suggest that PFE contains bioactive compounds capable of altering biomarkers involving oxidative stress and androgen signaling in prostate tumor and normal-appearing adjacent tissue. No alterations in the IGF axis were noted. This finding of study adherence and target activity provides a rationale for the further investigation of PFE in the active surveillance population.

Prognostic Significance of Nuclear Factor Kappa B Expression in Locally Advanced Cervical Cancer Patients Treated Definitively With Concurrent Chemoradiation

OBJECTIVES

Nuclear factor kappa B (NFkB) is a transcription factor shown to confer treatment resistance in tumors. A previous report suggested an association between pretreatment NFkB and poorer outcomes for cervical cancer patients treated with chemoradiation therapy (CRT). We aimed to validate their findings in a larger patient cohort.

MATERIALS AND METHODS

This Institutional Review Board approved study included patients with locally advanced cervical cancer patients treated with CRT. Evaluation of both nuclear and cytoplasmic immunoreactivity for NFkB was scored semiquantitatively by 3 pathologists. Cytoplasmic positivity incorporated both the intensity and percentage of immunoreactivity in invasive carcinoma (H-score), whereas nuclear positivity was assessed by percentage of positive cells. Outcomes were stratified by NFkB overexpression and tumor characteristics. Overall survival (OS), progression-free survival (PFS), distant metastases-free survival (DMFS), and local regional control (LC) were obtained using Kaplan-Meier and differences between groups were evaluated by the log-rank test. Hazard ratios were obtained using Cox regression for both univariate and multivariate analyses.

RESULTS

The mean age was 51 years old and most (78.57%) had locally advanced disease. Five-year OS, PFS, LC, and DMFS in the entire cohort were 57.18% (confidence interval [CI], 34.06%-74.82%), 48.07% (CI, 25.50%-67.52%), 72.11% (CI, 49.96%-85.73%), and 62.85% (CI, 36.33%-80.82%), respectively. There was no significant association between NFkB expression (H-index ≥180) and 3-year and 5-year OS (P-value=0.34), PFS (P-value=0.21), LC (P-value=0.86), or DMFS (P-value=0.18).

CONCLUSIONS

Our study demonstrated that cytoplasmic NFkB-p65 expression (H-index ≥180) was associated with a nonstatistically significant trend toward poor clinical outcomes in locally advanced cervical cancer patients treated definitively with CRT.

NF-κB signaling promotes castration-resistant prostate cancer initiation and progression

Prostate Cancer (PCa) is the second leading cause of cancer-related death in men. Adenocarcinoma of the prostate is primarily composed of Androgen Receptor-positive (AR⁺) luminal cells that require AR transcriptional activity for survival and proliferation. As a consequence, androgen deprivation and anti-androgens are used to treat PCa patients whose disease progresses following attempted surgical or radiation interventions. Unfortunately, patients with advanced PCa can develop incurable castration-resistant PCa (CRPCa) due to mutated, variant, or overexpressed AR. Conversely, low or no AR accumulation or activity can also underlie castration resistance. Whether CRPCa is due to aberrant AR activity or AR independence, NF-κB signaling is also implicated in the initiation and maintenance of CRPCa and, thus, the NF-κB pathway may be a promising alternative therapeutic target. In this review, we present evidence that NF-κB signaling promotes CRPCa initiation and progression, describe the dichotomic role of NF-κB in the regulation of AR expression and activity and outline studies that explore NF-κB inhibitors as PCa therapies.

Plant Bioactives and the Prevention of Prostate Cancer: Evidence from Human Studies

Prostate cancer has become the most common form of non-cutaneous (internal) malignancy in men, accounting for 26% of all new male visceral cancer cases in the UK. The aetiology and pathogenesis of prostate cancer are not understood, but given the age-adjusted geographical variations in prostate cancer incidence quoted in epidemiological studies, there is increasing interest in nutrition as a relevant factor. In particular, foods rich in phytochemicals have been proposed to reduce the risk of prostate cancer. Epidemiological studies have reported evidence that plant-based foods including cruciferous vegetables, garlic, tomatoes, pomegranate and green tea are associated with a significant reduction in the progression of prostate cancer. However, while there is well-documented mechanistic evidence at a cellular level of the manner by which individual dietary components may reduce the risk of prostate cancer or its progression, evidence from intervention studies is limited. Moreover, clinical trials investigating the link between the dietary bioactives found in these foods and prostate cancer have reported varied conclusions. Herein, we review the plant bioactives for which there is substantial evidence from epidemiological and human intervention studies. The aim of this review is to provide important insights into how particular plant bioactives (e.g., sulfur-containing compounds, carotenoids and polyphenols) present in commonly consumed food groups may influence the development and progression of prostate cancer.

GAPDH Overexpression in the T Cell Lineage Promotes Angioimmunoblastic T Cell Lymphoma through an NF-κB-Dependent Mechanism

GAPDH is emerging as a key player in T cell development and function. To investigate the role of GAPDH in T cells, we generated a transgenic mouse model overexpressing GAPDH in the T cell lineage. Aged mice developed a peripheral Tfh-like lymphoma that recapitulated key molecular, pathological, and immunophenotypic features of human angioimmunoblastic T cell lymphoma (AITL). GAPDH induced non-canonical NF-κB pathway activation in mouse T cells, which was strongly activated in human AITL. We developed a NIK inhibitor to reveal that targeting the NF-κB pathway prolonged AITL-bearing mouse survival alone and in combination with anti-PD-1. These findings suggest the therapeutic potential of targeting NF-κB signaling in AITL and provide a model for future AITL therapeutic investigations.

Pharmacological Inhibition of NFκB Reduces Prostate Cancer Related Osteoclastogenesis In Vitro and Osteolysis Ex Vivo

NFκB is implicated in cancer and bone remodelling, and we have recently reported that the verified NFκB inhibitor Parthenolide (PTN) reduced osteolysis and skeletal tumour growth in models of metastatic breast cancer. Here, we took advantage of in vitro and ex vivo bone cell and organ cultures to study the effects of PTN on the ability of prostate cancer cells and their derived factors to regulate bone cell activity and osteolysis. PTN inhibited the in vitro growth of a panel of human, mouse and rat prostate cancer cells in a concentration-dependent manner with a varying degree of potency. In prostate cancer cell-osteoclast co-cultures, the rat Mat-Ly-Lu, but not human PC3 or mouse RM1-BT, enhanced RANKL stimulated osteoclast formation and PTN reduced these effects without affecting prostate cancer cell viability. In the absence of cancer cells, PTN reduced the support of Mat-Ly-Lu conditioned medium for the adhesion and spreading of osteoclast precursors, and survival of mature osteoclasts. Pre-exposure of osteoblasts to PTN prior to the addition of conditioned medium from Mat-Ly-Lu cells suppressed their ability to support the formation of osteoclasts by inhibition of RANKL/OPG ratio. PTN enhanced the ability of Mat-Ly-Lu derived factors to increase calvarial osteoblast differentiation and growth. Ex vivo, PTN enhanced bone volume in calvaria organ-Mat-Ly-Lu cell co-culture, without affecting Mat-Ly-Lu viability or apoptosis. Mechanistic studies in osteoclasts and osteoblasts confirmed that PTN inhibit NFκB activation related to derived factors from Mat-Ly-Lu cells. Collectively, these findings suggest that pharmacological inhibition of the skeletal NFκB signalling pathway reduces prostate cancer related osteolysis, but further studies in the therapeutic implications of NFκB inhibition in cells of the osteoblastic lineage are needed.

Validation of the prognostic value of NF-κB p65 in prostate cancer: A retrospective study using a large multi-institutional cohort of the Canadian Prostate Cancer Biomarker Network

BACKGROUND

The identification of patients with high-risk prostate cancer (PC) is a major challenge for clinicians, and the improvement of current prognostic parameters is an unmet clinical need. We and others have identified an association between the nuclear localization of NF-κB p65 and biochemical recurrence (BCR) in PC in small and/or single-centre cohorts of patients.

METHODS AND FINDINGS

In this study, we accessed 2 different multi-centre tissue microarrays (TMAs) representing cohorts of patients (Test-TMA and Validation-TMA series) of the Canadian Prostate Cancer Biomarker Network (CPCBN) to validate the association between p65 nuclear frequency and PC outcomes. Immunohistochemical staining of p65 was performed on the Test-TMA and Validation-TMA series, which include PC tissues from patients treated by first-line radical prostatectomy (n = 250 and n = 1,262, respectively). Two independent observers evaluated the p65 nuclear frequency in digital images of cancer tissue and benign adjacent gland tissue. Kaplan-Meier curves coupled with a log-rank test and univariate and multivariate Cox regression models were used for statistical analyses of continuous values and dichotomized data (cutoff of 3%). Multivariate analysis of the Validation-TMA cohort showed that p65 nuclear frequency in cancer cells was an independent predictor of BCR using continuous (hazard ratio [HR] 1.02 [95% CI 1.00-1.03], p = 0.004) and dichotomized data (HR 1.33 [95% CI 1.09-1.62], p = 0.005). Using a cutoff of 3%, we found that this biomarker was also associated with the development of bone metastases (HR 1.82 [95% CI 1.05-3.16], p = 0.033) and PC-specific mortality (HR 2.63 [95% CI 1.30-5.31], p = 0.004), independent of clinical parameters. BCR-free survival, bone-metastasis-free survival, and PC-specific survival were shorter for patients with higher p65 nuclear frequency (p < 0.005). As the small cores on TMAs are a limitation of the study, a backward validation of whole PC tissue section will be necessary for the implementation of p65 nuclear frequency as a PC biomarker in the clinical workflow.

CONCLUSIONS

We report the first study using the pan-Canadian multi-centre cohorts of CPCBN and validate the association between increased frequency of nuclear p65 frequency and a risk of disease progression.

The Effect of P-Glycoprotein (P-gp), Nuclear Factor-Kappa B (Nf-κb), and Aldehyde Dehydrogenase-1 (ALDH-1) Expression on Metastases, Recurrence and Survival in Advanced Breast Cancer Patients

Objective: To investigate the level of three drug resistance proteins; P-glycoprotein 1 (P-gp), nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) and aldehyde dehydrogenase isoform 1 (ALDH1) expression and their relationship to metastasis, recurrence and survival in advanced breast cancer patients that received neoadjuvant chemotherapy. Methods: This study is a combination of prospective and retrospective cohort study involving one hundred and thirty one cases of advanced stage invasive breast cancer that have received neoadjuvant chemotherapy. Initial biopsy specimens (incisional biopsy or core biopsy) were taken from paraffin blocks. Immunohistochemistry (IHC) was used to detect P-gp, NF-κB, and ALDH1 expression. Prospectively analysed patients were followed for five years and evaluated for recurrence and death. Results: The expression of P-gp has no significant statistical correlation to metastases (p = 0.659), recurrence (p = 0.862) and survival (p = 0.835) in advanced stage breast cancer patients who received neoadjuvant chemotherapy. Similarly, ALDH1 was not correlated to metastases (p=0.120), recurrence (p = 0.186) and survival (p = 0.254) statistically. We found that NF-κB expression showed a significant correlation to metastases (p=0.004), recurrence (p = 0.016) and overall survival (p = 0.041) in advanced stage breast cancer patients after neoadjuvant chemotherapy. Conclusion: NF-κB expression is a potential marker that can be used to assess or to predict increasing risk of metastases, recurrence and survival in advanced stage breast cancer patients who receive neoadjuvant chemotherapy.

PITX2 methylation: a novel and effective biomarker for monitoring biochemical recurrence risk of prostate cancer

AIMS

Prostate cancer is one of the most common malignancies in men. Biochemical recurrence (BCR) and progression following curative treatment pose a significant public health challenge. Thus, it is essential to explore effective biomarkers for disease progression monitoring and risk stratification. The promoter region of the paired-like homeodomain transcription factor 2 (PITX2) gene has been found to be frequently methylated in prostate cancer. However, the prognostic role of PITX2 methylation in prostate cancer and which patients most likely to be recommended for PITX2 methylation tests to assess BCR risk remain controversial. Therefore, a systematic review was performed to explore the relationship of PITX2 methylation with the BCR risk of prostate cancer.

METHODS

The PubMed, EMBASE, and Cochrane Library databases were systematically searched for eligible studies. Seven studies with a total of 2185 patients were included. Pooled hazard ratios (HRs) and corresponding 95% confidence intervals (CIs) were calculated.

RESULTS

The overall HR was 2.71 (95% CI, 2.21-3.31), suggesting that PITX2 methylation has an adverse impact on BCR of prostate cancer. The pooled estimate of 5-year BCR-free survival for patients with a high methylation status was significantly lower than that for patients with a low methylation status (71% vs 90%; odds ratio [OR] = 3.50; 95% CI, 2.67-4.60, P = .000). A subgroup analysis was conducted according to detection method; the combined HRs were 2.68 (95% CI, 2.02-3.55) for quantitative methylation-specific PCR (qMSP) and 3.29 (95% CI, 2.31-4.68) for microarray EpiChip. In subgroups defined by region, Gleason score, pathological stage, surgical margin status and ethnicity, high methylation status was also associated with BCR of prostate cancer.

CONCLUSIONS

As an effective biomarker, PITX2 methylation is feasible for individualized BCR risk assessment of prostate cancer following radical prostatectomy.

Ectopic fibroblast growth factor receptor 1 promotes inflammation by promoting nuclear factor-κB signaling in prostate cancer cells

Initiation of expression of fibroblast growth factor receptor 1 (FGFR1) concurrent with loss of FGFR2 expression is a well-documented event in the progression of prostate cancer (PCa). Although it is known that some FGFR isoforms confer advantages in cell proliferation and survival, the mechanism by which the subversion of different FGFR isoforms contributes to PCa progression is incompletely understood. Here, we report that fibroblast growth factor (FGF) promotes NF-κB signaling in PCa cells and that this increase is associated with FGFR1 expression. Disruption of FGFR1 kinase activity abrogated both FGF activity and NF-κB signaling in PCa cells. Of note, the three common signaling pathways downstream of FGFR1 kinase, extracellular signal-regulated kinase 1/2 (ERK1/2), phosphoinositide 3-kinase (PI3K/AKT), and phosphoinositide phospholipase Cγ (PLCγ), were not required for FGF-mediated NF-κB signaling. Instead, transforming growth factor β-activating kinase 1 (TAK1), a central regulator of the NF-κB pathway, was required for FGFR1 to stimulate NF-κB signaling. Moreover, we found that FGFR1 promotes NF-κB signaling in PCa cells by reducing TAK1 degradation and thereby supporting sustained NF-κB activation. Consistently, Fgfr1 ablation in the transgenic adenocarcinoma of the mouse prostate (TRAMP) model reduced inflammation in the tumor microenvironment. In contrast, activation of the FGFR1 kinase in the juxtaposition of chemical-induced dimerization (CID) and kinase 1 (JOCK1) mouse model increased inflammation. As inflammation plays an important role in PCa initiation and progression, these findings suggest that ectopically expressed FGFR1 promotes PCa progression, at least in part, by increasing inflammation in the tumor microenvironment.

Suppression of ribosomal protein RPS6KB1 by Nexrutine increases sensitivity of prostate tumors to radiation

Radiation therapy (XRT) is a standard treatment for prostate cancer (PCa). Although dose escalation increases local control, toxicity hampers further escalation. Broader improvement will be possible by the addition of adjuvant therapies, which can synergize with radiation and thus improve efficacy. We have identified a natural compound (Nexrutine, Nx) that inhibits the survival and growth of PCa cells in combination with radiation. Combination studies demonstrated strong interaction between Nx and radiation both in vitro in multiple PCa cell lines and in the Transgenic adenocarcinoma of mouse prostate (TRAMP) model. Nx potentiated growth inhibitory effects of IR by down regulating ribosomal protein S6K (RPS6KB1), CyclinD1, Chk1 and HIF-1 α and prolonging G2/M checkpoint block. RPS6KB1 is upregulated in prostate cancers and its expression is correlated with tumor grade. Knockdown of RPS6KB1 in PCa cells increased their sensitivity toward radiation-induced survival inhibition. Overall, we provide scientific evidence (i) in support of Nx as an adjuvant in PCa patients receiving XRT (ii) suggesting that RPS6KB1 is an important player in Nx-mediated combinatorial benefits and emphasizes that RPS6KB1 is a novel target for PCa treatment. These data underscore the need to test the agent in additional preclinical models to validate these observations.

Calcium and Nuclear Signaling in Prostate Cancer

Recently, there have been a number of developments in the fields of calcium and nuclear signaling that point to new avenues for a more effective diagnosis and treatment of prostate cancer. An example is the discovery of new classes of molecules involved in calcium-regulated nuclear import and nuclear calcium signaling, from the G protein-coupled receptor (GPCR) and myosin families. This review surveys the new state of the calcium and nuclear signaling fields with the aim of identifying the unifying themes that hold out promise in the context of the problems presented by prostate cancer. Genomic perturbations, kinase cascades, developmental pathways, and channels and transporters are covered, with an emphasis on nuclear transport and functions. Special attention is paid to the molecular mechanisms behind prostate cancer progression to the malignant forms and the unfavorable response to anti-androgen treatment. The survey leads to some new hypotheses that connect heretofore disparate results and may present a translational interest.

A review of pomegranate in prostate cancer

Background

Preclinical studies showing that pomegranate juice and its components inhibit prostate cancer led to multiple clinical trials to determine whether pomegranate products could slow the growth of prostate cancer. This review summarizes the preclinical data and discusses the results of the clinical trials.

Methods

Trials targeted patients on active surveillance, neoadjuvant patients, patients with biochemical recurrence (BCR) following local therapy for prostate cancer, and patients with metastatic castration-resistant prostate cancer (mCRPC).

Results

In the BCR patient population, early phase II trials of both pomegranate juice and extract showed significant lengthening of PSA doubling time (PSADT), and confirmed the safety of pomegranate products. While a placebo-controlled phase III trial determined that pomegranate extract did not significantly prolong PSADT in BCR patients, a preplanned subset analysis of patients with the manganese superoxide dismutase (MnSOD) AA genotype showed greater PSADT lengthening on the pomegranate extract arm. In the neoadjuvant population, a large trial demonstrated a significant increase in urolithin A and a non-significant reduction in 8-OHdG, a marker of oxidation in prostate cancer tissue, on the pomegranate arm vs. the placebo arm. In addition, a randomized clinical trial of a polyphenol-rich multi-component food supplement tablet, including 31.25% pomegranate extract, found significant slowing of PSA increase in the food supplement arm vs. placebo in men on active surveillance and those experiencing biochemical recurrence.

Conclusions

Pomegranate juice and extract are safe but did not significantly improve outcomes in BCR patients in a large placebo controlled trial. However a subset of BCR patients with the MnSOD AA genotype appear to respond positively to the antioxidant effects of pomegranate treatment. Phase II trials of 100% pomegranate products in neoadjuvant patients and patients with mCRPC were negative. A multi-component food supplement showed promising results in a phase II study in active surveillance and BCR patients.

microRNA-372 Suppresses Migration and Invasion by Targeting p65 in Human Prostate Cancer Cells

Prostate cancer (PCa) is one of the most prevalent malignant tumors. microRNAs (miRNAs) play an important role in cancer initiation, progression, and metastasis, and their roles in PCa are becoming more apparent. In this study, we found that microRNA-372 (miR-372) is downregulated in human PCa and inhibits the proliferation activity, migration, and invasion of DU145 cells. Subsequently, p65 is confirmed as a target of miR-372, and knockdown of p65 expression similarly resulted in decreased proliferation activity, migration, and invasion. CDK8, MMP-9, and prostate-specific antigen were involved in both these processes. Taken together, our results show evidence that miR-372 may function as a tumor suppressor gene by regulating p65 in PCa and may provide a strategy for blocking PCa metastasis.

Da0324, an inhibitor of nuclear factor-κB activation, demonstrates selective antitumor activity on human gastric cancer cells

Background

The transcription factor nuclear factor-κB (NF-κB) is constitutively activated in a variety of human cancers, including gastric cancer. NF-κB inhibitors that selectively kill cancer cells are urgently needed for cancer treatment. Curcumin is a potent inhibitor of NF-κB activation. Unfortunately, the therapeutic potential of curcumin is limited by its relatively low potency and poor cellular bioavailability. In this study, we presented a novel NF-κB inhibitor named Da0324, a synthetic asymmetric mono-carbonyl analog of curcumin. The purpose of this study is to research the expression of NF-κB in gastric cancer and the antitumor activity and mechanism of Da0324 on human gastric cancer cells.

Methods

The expressions between gastric cancer tissues/cells and normal gastric tissues/cells of NF-κB were evaluated by Western blot. The inhibition viability of compounds on human gastric cancer cell lines SGC-7901, BGC-823, MGC-803, and normal gastric mucosa epithelial cell line GES-1 was assessed with the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide assay. Absorption spectrum method and high-performance liquid chromatography method detected the stability of the compound in vitro. The compound-induced changes of inducible NF-κB activation in the SGC-7901 and BGC-823 cells were examined by Western blot analysis and immunofluorescence methods. The antitumor activity of compound was performed by clonogenic assay, matrigel invasion assay, flow cytometric analysis, Western blot analysis, and Hoechst 33258 staining assay.

Results

High levels of p65 were found in gastric cancer tissues and cells. Da0324 displayed higher growth inhibition against several types of gastric cancer cell lines and showed relatively low toxicity to GES-1. Moreover, Da0324 was more stable than curcumin in vitro. Western blot analysis and immunofluorescence methods showed that Da0324 blocked NF-κB activation. In addition, Da0324 significantly inhibited tumor proliferation and invasion, arrested the cell cycle, and induced apoptosis in vitro.

Conclusion

The asymmetric mono-carbonyl analog of curcumin Da0324 exhibited significantly improved antigastric cancer activity. Da0324 may be a promising NF-κB inhibitor for the selective targeting of cancer cells. However, further studies are needed in animals to validate these findings for the therapeutic use of Da0324.

Combination of α-Tomatine and Curcumin Inhibits Growth and Induces Apoptosis in Human Prostate Cancer Cells

α-Tomatine is a glycoalkaloid found in tomatoes and curcumin is a major yellow pigment of turmeric. In the present study, the combined effect of these two compounds on prostate cancer cells was studied. Treatment of different prostate cancer cells with curcumin or α-tomatine alone resulted in growth inhibition and apoptosis in a concentration-dependent manner. Combinations of α-tomatine and curcumin synergistically inhibited the growth and induced apoptosis in prostate cancer PC-3 cells. Effects of the α-tomatine and curcumin combination were associated with synergistic inhibition of NF-κB activity and a potent decrease in the expression of its downstream gene Bcl-2 in the cells. Moreover, strong decreases in the levels of phospho-Akt and phosphor-ERK1/2 were found in PC-3 cells treated with α-tomatine and curcumin in combination. In animal experiment, SCID mice with PC-3 xenograft tumors were treated with α-tomatine and curcumin. Combination of α-tomatine and curcumin more potently inhibited the growth of PC-3 tumors than either agent alone. Results from the present study indicate that α-tomatine in combination with curcumin may be an effective strategy for inhibiting the growth of prostate cancer.

TNF signaling mediates an enzalutamide-induced metastatic phenotype of prostate cancer and microenvironment cell co-cultures

The dramatic responses tumors display to targeted therapies are limited by acquired or pre-existing mechanisms of therapy resistance. We recently discovered that androgen receptor blockade by the anti-androgen enzalutamide paradoxically enhanced metastasis and that these pro-metastatic effects were mediated by the chemoattractant CCL2. CCL2 is regulated by TNF, which is negatively regulated by androgen signaling. Thus, we asked if TNF mediates the pro-metastatic effects of enzalutamide. We found that androgen withdrawal or enzalutamide induced TNF mRNA and protein secretion in castration resistant prostate cancer (C4-2) cells, but not in macrophage-like (THP1) or myofibroblast-like (WPMY1) cells. Androgen deprivation therapy (ADT) induced autocrine CCL2 expression in C4-2 (as well as a murine CRPC cell line), while exogenous TNF induced CCL2 in THP1 and WPMY1. TNF was most potent in myofibroblast cultures, suggesting ADT induces CCL2 via paracrine interactions within the tumor microenvironment. A soluble TNF receptor (etanercept) blocked enzalutamide-induced CCL2 protein secretion and mRNA, implying dependence on secreted TNF. A small molecule inhibitor of CCR2 (the CCL2 receptor) significantly reduced TNF induced migration, while etanercept inhibited enzalutamide-induced migration and invasion of C4-2. Analysis of human prostate cancers suggests that a TNF-CCL2 paracrine loop is induced in response to ADT and might account for some forms of prostate cancer therapy resistance.

Potential Cross-Talk between Alternative and Classical NF-κB Pathways in Prostate Cancer Tissues as Measured by a Multi-Staining Immunofluorescence Co-Localization Assay

Background

While the classical NF-κB/p65 pathway is known to be involved in prostate cancer progression and is associated with poor patient outcome, the role of the NF-κB /RelB alternative protein is not well defined. Here we analyzed the activation of both NF-κB pathways in prostate cancer tissues and correlate this activation with clinical features of the disease.

Methods

A multiple immunofluorescence technique was employed to concomitantly and quantitatively visualize the nuclear localization of p65 and RelB in 200 paraffin embedded samples. Epithelia were defined using appropriate fluorochrome markers and the resulting immunofluorescent signals were quantified with an automated scoring system.

Results

The nuclear frequency of p65 was found to be significantly increased in tumor tissues as compared with normal adjacent tissue, whereas the frequency for RelB was decreased (p < 0.001, Wilcoxon test). As previously reported, p65 nuclear frequency was associated with a risk of biochemical recurrence. Although, RelB nuclear frequency alone did not predict recurrence, the presence of activated RelB reduced the risk of recurrence associated with the activation of p65.

Conclusion

For the first time p65/RelB co-distribution was assessed in prostate cancer tissues and suggested a negative crosstalk between the two NF-κB pathways in prostate cancer progression.

A randomized, double-blind, placebo-controlled study of the effects of pomegranate extract on rising PSA levels in men following primary therapy for prostate cancer

BACKGROUND

The primary objective of this study was to compare the effects of pomegranate juice on PSA doubling times (PSADT) in subjects with rising PSA levels after primary therapy for prostate cancer.

METHODS

Double-blind, placebo-controlled multi-institutional study, evaluated the effects of pomegranate liquid extract on serum PSA levels. The primary end point of this study was change in serum PSADT. Additional secondary and exploratory objectives were to evaluate the safety of pomegranate juice and to determine the interaction of manganese superoxide dismutase (MnSOD) AA genotype and pomegranate treatment on PSADT.

RESULTS

One-hundred eighty-three eligible subjects were randomly assigned to the active and placebo groups with a ratio of 2:1 (extract N=102; placebo N=64; juice N=17). The majority of adverse events were of moderate or mild grade. Median PSADT increased from 11.1 months at baseline to 15.6 months in the placebo group (P<0.001) compared with an increase from 12.9 months at baseline to 14.5 months in the extract group (P=0.13) and an increase from 12.7 at baseline to 20.3 in the juice group (P=0.004). However, none of these changes were statistically significant between the three groups (P>0.05). Placebo AA patients experienced a 1.8 month change in median PSADT from 10.9 months at baseline to 12.7 months (P=0.22), while extract patients experienced a 12 month change in median PSADT from 13.6 at baseline to 25.6 months (P=0.03).

CONCLUSIONS

Compared with placebo, pomegranate extract did not significantly prolong PSADT in prostate cancer patients with rising PSA after primary therapy. A significant prolongation in PSADT was observed in both the treatment and placebo arms. Men with the MnSOD AA genotype may represent a group that is more sensitive to the antiproliferative effects of pomegranate on PSADT; however, this finding requires prospective hypothesis testing and validation.

Potential Effects of Pomegranate Polyphenols in Cancer Prevention and Therapy

Cancer is the second leading cause of death and is becoming the leading one in old age. Vegetable and fruit consumption is inversely associated with cancer incidence and mortality. Currently, interest in a number of fruits high in polyphenols has been raised due to their reported chemopreventive and/or chemotherapeutic potential. Pomegranate has been shown to exert anticancer activity, which is generally attributed to its high content of polyphenols. This review provides a comprehensive analysis of known targets and mechanisms along with a critical evaluation of pomegranate polyphenols as future anticancer agents. Pomegranate evokes antiproliferative, anti-invasive, and antimetastatic effects, induces apoptosis through the modulation of Bcl-2 proteins, upregulates p21 and p27, and downregulates cyclin-cdk network. Furthermore, pomegranate blocks the activation of inflammatory pathways including, but not limited to, the NF-κB pathway. The strongest evidence for its anticancer activity comes from studies on prostate cancer. Accordingly, some exploratory clinical studies investigating pomegranate found a trend of efficacy in increasing prostate-specific antigen doubling time in patients with prostate cancer. However, the genotoxicity reported for pomegranate raised certain concerns over its safety and an accurate assessment of the risk/benefit should be performed before suggesting the use of pomegranate or its polyphenols for cancer-related therapeutic purposes.

NF-κB in cancer therapy

The transcription factor nuclear factor kappa B (NF-κB) has attracted increasing attention in the field of cancer research from last few decades. Aberrant activation of this transcription factor is frequently encountered in a variety of solid tumors and hematological malignancies. NF-κB family members and their regulated genes have been linked to malignant transformation, tumor cell proliferation, survival, angiogenesis, invasion/metastasis, and therapeutic resistance. In this review, we highlight the diverse molecular mechanism(s) by which the NF-κB pathway is constitutively activated in different types of human cancers, and the potential role of various oncogenic genes regulated by this transcription factor in cancer development and progression. Additionally, various pharmacological approaches employed to target the deregulated NF-κB signaling pathway, and their possible therapeutic potential in cancer therapy is also discussed briefly.

Chronic inflammatory mediators enhance prostate cancer development and progression

Chronic inflammation is postulated to influence prostate cancer progression. Preclinical studies have claimed that inflammatory mediators are involved in prostate cancer development and therefore suggested these as attractive targets for intervention. However, among the many pro-inflammatory mediators, there is no consensus regarding the identity of the primary one(s). In clinical studies, chronic inflammation has been found in prostate tumor specimens, and tissues resected for treatment of benign prostatic hyperplasia (BPH). Although collective evidence from molecular, experimental and clinical data suggests that inflammation can contribute or promote prostate carcinogenesis, an etiologic link has not yet been established. Moreover, the role of chronic inflammation in the onset of castration resistant and metastatic disease is unclear. Therefore it is important to open a dialog regarding recent findings on how chronic inflammatory mediators contribute to prostate cancer progression, and their usefulness to prevent disease progression. In this commentary, we assess the current literature with respect to chronic inflammation as a potential initiator and promoter of prostate carcinogenesis and discuss the prospects for its potential clinical applications.

Impact of prostate inflammation on lesion development in the POET3(+)Pten(+/-) mouse model of prostate carcinogenesis

Evidence linking prostatitis and prostate cancer development is contradictory. To study this link, the POET3 mouse, an inducible model of prostatitis, was crossed with a Pten-loss model of prostate cancer (Pten(+/-)) containing the ROSA26 luciferase allele to monitor prostate size. Prostatitis was induced, and prostate bioluminescence was tracked over 12 months, with lesion development, inflammation, and cytokine expression analyzed at 4, 8, and 12 months and compared with mice without induction of prostatitis. Acute prostatitis led to more proliferative epithelium and enhanced bioluminescence. However, 4 months after initiation of prostatitis, mice with induced inflammation had lower grade pre-neoplastic lesions. A trend existed toward greater development of carcinoma 12 months after induction of inflammation, including one of two mice with carcinoma developing perineural invasion. Two of 18 mice at the later time points developed lesions with similarities to proliferative inflammatory atrophy, including one mouse with associated carcinoma. Pten(+/-) mice developed spontaneous inflammation, and prostatitis was similar among groups of mice at 8 and 12 months. Analyzed as one cohort, lesion number and grade were positively correlated with prostatitis. Specifically, amounts of CD11b(+)Gr1(+) cells were correlated with lesion development. These results support the hypothesis that myeloid-based inflammation is associated with lesion development in the murine prostate, and previous bouts of CD8-driven prostatitis may promote invasion in the Pten(+/-) model of cancer.

VIP induces NF-κB1-nuclear localisation through different signalling pathways in human tumour and non-tumour prostate cells

The nuclear factor κB (NF-κB) is a powerful activator of angiogenesis, invasion and metastasis. Transactivation and nuclear localisation of NF-κB is an index of recurrence in prostate cancer. Vasoactive intestinal peptide (VIP) exerts similar effects in prostate cancer models involving increased expression of vascular endothelial growth factor (VEGF) and cyclooxygenase-2 (COX-2) which are related to NF-κB transactivation. Here we studied differential mechanisms of VIP-induced NF-κB transactivation in non-tumour RWPE-1 and tumour LNCaP and PC3 human prostate epithelial cells. Immunofluorescence studies showed that VIP increases translocation of the p50 subunit of NF-κB1 to the nucleus, an effect that was inhibited by curcumin. The signalling transduction pathways involved are different depending on cell transformation degree. In control cells (RWPE1), the effect is mediated by protein kinase A (PKA) activation and does not implicate extracellular signal-regulated kinase (ERK) or phosphoinositide 3-kinase (PI3-K) pathways whereas the opposite is true in tumour LNCaP and PC3 cells. Exchange protein directly activated by cAMP (EPAC) pathway is involved in transformed cells but not in control cells. Curcumin blocks the activating effect of VIP on COX-2 promoter/prostaglandin E2 (PGE2) production and VEGF expression and secretion. The study incorporates direct observation on COX-2 promoter and suggests that VIP effect on VEGF may be indirectly mediated by PGE2 after being synthesised by COX-2, thus amplifying the initial signal. We show that the signalling involved in VIP effects on VEGF is cAMP/PKA in non-tumour cells and cAMP/EPAC/ERK/PI3K in tumour cells which coincides with pathways mediating p50 nuclear translocation. Thus, VIP appears to use different pathways for NF-κB1 (p50) transactivation in prostate epithelial cells depending on whether they are transformed or not. Transformed cells depend on pro-survival and pro-proliferative signalling pathways involving ERK, PI3-K and cAMP/EPAC which supports the potential therapeutic value of these targets in prostate cancer.

The RelB alternative NF-kappaB subunit promotes autophagy in 22Rv1 prostate cancer cells in vitro and affects mouse xenograft tumor growth in vivo

Background

The involvement of NF-κB signaling in prostate cancer (PCa) has largely been established through the study of the classical p65 subunit. Nuclear localization of p65 in PCa patient tissues has been shown to correlate with biochemical recurrence, while in vitro studies have demonstrated that the classical NF-κB signaling pathway promotes PCa progression and metastatic potential. More recently, the nuclear location of RelB, a member of the alternative NF-κB signaling, has also been shown to correlate with the Gleason score. The current study aims to clarify the role of alternative NF-κB in PCa cells by exploring, in vitro and in vivo, the effects of RelB overexpression on PCa biology.

Methods

Using a lentivirus-expression system, we constitutively overexpressed RelB or control GFP into 22Rv1 cells and monitored alternative transcriptional NF-κB activity. In vivo, tumor growth was assessed after the injection of 22Rv1-derived cells into SCID mice. In vitro, the impact of RelB on 22Rv1 cell proliferation was evaluated in monolayer culture. The anchorage-independent cell growth of derived-22Rv1 cells was assessed by soft agar assay. Apoptosis and autophagy were evaluated by Western blot analysis in 22Rv1-derived cells cultured in suspension using poly-HEMA pre-coated dishes.

Results

The overexpression of RelB in 22Rv1 cells induced the constitutive activation of the alternative NF-κB pathway. In vivo, RelB expression caused a lag in the initiation of 22Rv1-induced tumors in SCID mice. In vitro, RelB stimulated the proliferation of 22Rv1 cells and reduced their ability to grow in soft agar. These observations may be reconciled by our findings that, when cultured in suspension on poly-HEMA pre-coated dishes, 22Rv1 cells expressing RelB were more susceptible to cell death, and more specifically to autophagy controlled death.

Conclusions

This study highlights a role of the alternative NF-κB pathway in proliferation and the controlled autophagy. Thus, the interplay of these properties may contribute to tumor survival in stress conditions while promoting PCa cells growth contributing to the overall tumorigenicity of these cells.

Beyond androgen deprivation: ancillary integrative strategies for targeting the androgen receptor addiction of prostate cancer

The large majority of clinical prostate cancers remain dependent on androgen receptor (AR) activity for proliferation even as they lose their responsiveness to androgen deprivation or antagonism. AR activity can be maintained in these circumstances by increased AR synthesis--often reflecting increased NF-κB activation; upregulation of signaling pathways that promote AR activity in the absence of androgens; and by emergence of AR mutations or splice variants lacking the ligand-binding domain, which render the AR constitutively active. Drugs targeting the N-terminal transactivating domain of the AR, some of which are now in preclinical development, can be expected to inhibit the activity not only of unmutated ARs but also of the mutant forms and splice variants selected for by androgen deprivation. Concurrent measures that suppress AR synthesis or boost AR turnover could be expected to complement the efficacy of such drugs. A number of nutraceuticals that show efficacy in prostate cancer xenograft models--including polyphenols from pomegranate, grape seed, and green tea, the crucifera metabolite diindolylmethane, and the hormone melatonin--have the potential to suppress AR synthesis via downregulation of NF-κB activity; clinical doses of salicylate may have analogous efficacy. The proteasomal turnover of the AR is abetted by diets with a high ratio of long-chain omega-3 to omega-6 fatty acids, which are beneficial in prostate cancer xenograft models; berberine and sulforaphane, by inhibiting AR's interaction with its chaperone Hsp90, likewise promote AR proteasomal degradation and retard growth of human prostate cancer in nude mice. Hinge region acetylation of the AR is required for optimal transactivational activity, and low micromolar concentrations of the catechin epigallocatechin-3-gallate (EGCG) can inhibit such acetylation--possibly explaining the ability of EGCG administration to suppress androgenic activity and cell proliferation in prostate cancer xenografts. Hence, it is proposed that regimens featuring an N-terminal domain-targeting drug, various nutraceuticals/drugs that downregulate NF-κB activity, and/or supplemental intakes of fish oil, berberine, sulforaphane, and EGCG have potential for blocking proliferation of prostate cancer by targeting its characteristic addiction to androgen receptor activity.

Recent insights into NF-κB signalling pathways and the link between inflammation and prostate cancer

Inflammation is involved in regulation of cellular events in prostate carcinogenesis through control of the tumour micro-environment. A variety of bone marrow-derived cells, including CD4+ lymphocytes, macrophages and myeloid-derived suppressor cells, are integral components of the tumour micro-environment. On activation by inflammatory cytokines, NF-κB complexes are capable of promoting tumour cell survival through anti-apoptotic signalling in prostate cancer (PCa). Positive feedback loops are able to maintain NF-κB activation. NF-κB activation is also associated with the metastatic phenotype and PCa progression to castration-resistant prostate cancer (CRPC). A novel role for inhibitor of NF-κB kinase (IKK)-α in NF-κB-independent PCa progression to metastasis and CRPC has recently been uncovered, providing a new mechanistic link between inflammation and PCa. Expansion of PCa progenitors by IKK-α may be involved in this process. In this review, we offer the latest evidence regarding the role of the NF-κB pathway in PCa and discuss therapeutic attempts to target the NF-κB pathways. We point out the need to further dissect inflammatory pathways in PCa in order to develop appropriate preventive measures and design novel therapeutic strategies.

NF-κB and COX-2 expression in nonmalignant endometrial lesions and cancer

OBJECTIVES

To examine the immunohistochemical expression of cyclooxygenase-2 (COX-2) and nuclear factor-κB (NF-κB) in benign endometrial polyps (EPs), endometrial hyperplasia (EH), endometrial intraepithelial neoplasia (EIN), and endometrioid endometrial cancer (EC).

METHODS

The immunohistochemical expression of COX-2 and NF-κB was performed using an Aperio Scanscope XT automated system in 218 patients with endometrioid EC and 107 patients with nonmalignant endometrial lesions: 53 with benign EPs, 37 with EH, and 17 with EIN.

RESULTS

COX-2 and NF-κB p50 expression were significantly lower in EC compared with nonmalignant lesions. We observed significant decreased NF-κB p65 expression in EC vs EPs (P < .001) and EH (P = .014) as well as in EIN vs. EPs (P = .01). For patients with EC, COX-2 correlated positively with NF-κB p65 and NF-κB p50 (P < .001). Grade 3 tumors had a higher mean expression of NF-κB p65 (P = .03). NF-κB p50, NF-κB p65, and COX-2 expression had no impact on survival.

CONCLUSIONS

We conclude that COX-2 and NF-κB expression are lower in EC compared with nonmalignant endometrial lesions. COX-2 and NF-κB expression have no prognostic value in EC.

Proteasome inhibition by bortezomib increases IL-8 expression in androgen-independent prostate cancer cells: the role of IKKα

Expression of the proinflammatory and proangiogenic chemokine IL-8, which is regulated at the transcriptional level by NF-κB, is constitutively increased in androgen-independent metastatic prostate cancer and correlates with poor prognosis. Inhibition of NF-κB-dependent transcription was used as an anticancer strategy for the development of the first clinically approved 26S proteasome inhibitor, bortezomib (BZ). Even though BZ has shown remarkable antitumor activity in hematological malignancies, it has been less effective in prostate cancer and other solid tumors; however, the mechanisms have not been fully understood. In this article, we report that proteasome inhibition by BZ unexpectedly increases IL-8 expression in androgen-independent prostate cancer PC3 and DU145 cells, whereas expression of other NF-κB-regulated genes is inhibited or unchanged. The BZ-increased IL-8 expression is associated with increased in vitro p65 NF-κB DNA binding activity and p65 recruitment to the endogenous IL-8 promoter. In addition, proteasome inhibition induces a nuclear accumulation of IκB kinase (IKK)α, and inhibition of IKKα enzymatic activity significantly attenuates the BZ-induced p65 recruitment to IL-8 promoter and IL-8 expression, demonstrating that the induced IL-8 expression is mediated, at least partly, by IKKα. Together, these data provide the first evidence, to our knowledge, for the gene-specific increase of IL-8 expression by proteasome inhibition in prostate cancer cells and suggest that targeting both IKKα and the proteasome may increase BZ effectiveness in treatment of androgen-independent prostate cancer.

Piperine, a Bioactive Component of Pepper Spice Exerts Therapeutic Effects on Androgen Dependent and Androgen Independent Prostate Cancer Cells

Prostate cancer is the most common solid malignancy in men, with 32,000 deaths annually. Piperine, a major alkaloid constituent of black pepper, has previously been reported to have anti-cancer activity in variety of cancer cell lines. The effect of piperine against prostate cancer is not currently known. Therefore, in this study, we investigated the anti-tumor mechanisms of piperine on androgen dependent and androgen independent prostate cancer cells. Here, we show that piperine inhibited the proliferation of LNCaP, PC-3, 22RV1 and DU-145 prostate cancer cells in a dose dependent manner. Furthermore, Annexin-V staining demonstrated that piperine treatment induced apoptosis in hormone dependent prostate cancer cells (LNCaP). Using global caspase activation assay, we show that piperine-induced apoptosis resulted in caspase activation in LNCaP and PC-3 cells. Further studies revealed that piperine treatment resulted in the activation of caspase-3 and cleavage of PARP-1 proteins in LNCaP, PC-3 and DU-145 prostate cancer cells. Piperine treatment also disrupted androgen receptor (AR) expression in LNCaP prostate cancer cells. Our evaluations further show that there is a significant reduction of Prostate Specific Antigen (PSA) levels following piperine treatment in LNCaP cells. NF-kB and STAT-3 transcription factors have previously been shown to play a role in angiogenesis and invasion of prostate cancer cells. Interestingly, treatment of LNCaP, PC-3 and DU-145 prostate cancer cells with piperine resulted in reduced expression of phosphorylated STAT-3 and Nuclear factor-κB (NF-kB) transcription factors. These results correlated with the results of Boyden chamber assay, wherein piperine treatment reduced the cell migration of LNCaP and PC-3 cells. Finally, we show that piperine treatment significantly reduced the androgen dependent and androgen independent tumor growth in nude mice model xenotransplanted with prostate cancer cells. Taken together, these results support further investigation of piperine as a potential therapeutic agent in the treatment of prostate cancer.

ETS transcription factor ESE1/ELF3 orchestrates a positive feedback loop that constitutively activates NF-κB and drives prostate cancer progression

Chromosomal translocations leading to deregulated expression of ETS transcription factors are frequent in prostate tumors. Here, we report a novel mechanism leading to oncogenic activation of the ETS factor ESE1/ELF3 in prostate tumors. ESE1/ELF3 was overexpressed in human primary and metastatic tumors. It mediated transforming phenotypes in vitro and in vivo and induced an inflammatory transcriptome with changes in relevant oncogenic pathways. ESE1/ELF3 was induced by interleukin (IL)-1β through NF-κB and was a crucial mediator of the phenotypic and transcriptional changes induced by IL-1β in prostate cancer cells. This linkage was mediated by interaction of ESE1/ELF3 with the NF-κB subunits p65 and p50, acting by enhancing their nuclear translocation and transcriptional activity and by inducing p50 transcription. Supporting these findings, gene expression profiling revealed an enrichment of NF-κB effector functions in prostate cancer cells or tumors expressing high levels of ESE1/ELF3. We observed concordant upregulation of ESE1/ELF3 and NF-κB in human prostate tumors that was associated with adverse prognosis. Collectively, our results define an important new mechanistic link between inflammatory signaling and the progression of prostate cancer.

Pomegranate Extracts in the Management of Men's Urologic Health: Scientific Rationale and Preclinical and Clinical Data

Multiple strands of research provide growing evidence that diet, nutrition, and life style play a role in the development and the course of urological diseases. Numerous micronutrients and polyphenols found in soy, green tea, and many fruits and vegetables have been described to impact diseases including erectile dysfunction, benign prostatic hyperplasia, and prostate cancer. However, oftentimes these reports lack both a scientific rationale and supportive evidence base. The efficacy of pomegranate, on the other hand, in the modulation of central biological processes like inflammation, hypoxia, and oxidative stress that are important in the pathogenesis of urological maladies has been robustly demonstrated in preclinical in vitro and in vivo studies. Moreover, clinical trials have further supported its use in the treatment of several diseases, in particular in the management of prostate cancer. Herein, we critically review the scientific knowledge about the current role and future prospects for the use of pomegranate extracts in the therapy of erectile dysfunction, benign prostatic hyperplasia, and prostate cancer.

Alpha-tomatine attenuation of in vivo growth of subcutaneous and orthotopic xenograft tumors of human prostate carcinoma PC-3 cells is accompanied by inactivation of nuclear factor-kappa B signaling

Background

Nuclear factor-kappa B (NF-κB) plays a role in prostate cancer and agents that suppress its activation may inhibit development or progression of this malignancy. Alpha (α)-tomatine is the major saponin present in tomato (Lycopersicon esculentum) and we have previously reported that it suppresses tumor necrosis factor-alpha (TNF-α)-induced nuclear translocation of nuclear factor-kappa B (NF-κB) in androgen-independent prostate cancer PC-3 cells and also potently induces apoptosis of these cells. However, the precise mechanism by which α-tomatine suppresses NF-κB nuclear translocation is yet to be elucidated and the anti-tumor activity of this agent in vivo has not been examined.

Methodology/ Principal Findings

In the present study we show that suppression of NF-κB activation by α-tomatine occurs through inhibition of I kappa B alpha (IκBα) kinase activity, leading to sequential suppression of IκBα phosphorylation, IκBα degradation, NF-κB/p65 phosphorylation, and NF-κB p50/p65 nuclear translocation. Consistent with its ability to induce apoptosis, α-tomatine reduced TNF-α induced activation of the pro-survival mediator Akt and its inhibition of NF-κB activation was accompanied by significant reduction in the expression of NF-κB-dependent anti-apoptotic (c-IAP1, c-IAP2, Bcl-2, Bcl-xL, XIAP and survivin) proteins. We also evaluated the antitumor activity of α-tomatine against PC-3 cell tumors grown subcutaneously and orthotopically in mice. Our data indicate that intraperitoneal administration of α-tomatine significantly attenuates the growth of PC-3 cell tumors grown at both sites. Analysis of tumor material indicates that the tumor suppressing effects of α-tomatine were accompanied by increased apoptosis and lower proliferation of tumor cells as well as reduced nuclear translocation of the p50 and p65 components of NF-κB.

Conclusion/ Significance

Our study provides first evidence for in vivo antitumor efficacy of α-tomatine against the human androgen-independent prostate cancer. The potential usefulness of α-tomatine in prostate cancer prevention and therapy requires further investigation.

Carnosic acid modulates Akt/IKK/NF-κB signaling by PP2A and induces intrinsic and extrinsic pathway mediated apoptosis in human prostate carcinoma PC-3 cells

This study investigates the efficacy of carnosic acid (CA), a polyphenolic diterpene, isolated from the plant rosemary (Rosemarinus officinalis), on androgen-independent human prostate cancer PC-3 cells. CA induced anti-proliferative effects in PC-3 cells in a concentration- and time-dependent manner, which was due to apoptotic induction as evident from flow-cytometry, DNA laddering and TUNEL assay. Apoptosis was associated with the activation of caspase-8, -9, -3 and -7, increase in Bax:Bcl-2 ratio, release of cytochrome-c and decrease in expression of inhibitor of apoptosis (IAP) family of proteins. Apoptosis was attenuated upon pretreatment with specific inhibitors of caspase-8 (Z-IETD-fmk) and caspase-9 (Z-LEHD-fmk) suggesting the involvement of both intrinsic and extrinsic apoptotic cascades. Further, apoptosis resulted from the inhibition of IKK/NF-κB pathway as evident from decreased DNA binding activity, nuclear translocation of p50 and p65 and IκBα phosphorylation. The down-regulation of IKK/NF-κB was associated with inhibition of Akt phosphorylation and its kinase activity with a concomitant increase in the serine/threonine protein phosphatase 2A (PP2A) activity. Pharmacologic inhibition of PP2A by okadaic acid and calyculin A, significantly reversed CA-mediated apoptotic events in PC-3 cells indicating that CA induced apoptosis by activation of PP2A through modulation of Akt/IKK/NF-κB pathway. In addition, CA induced apoptosis in another androgen refractory prostate cancer DU145 cells via intrinsic pathway as evidenced from the activation of caspase 3, cleavage of PARP, increase in Bax:Bcl-2 ratio and cytochrome-c release. Carnosic acid, therefore, may have the potential for use in the prevention and/or treatment 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.

Peroxiredoxin 1 stimulates endothelial cell expression of VEGF via TLR4 dependent activation of HIF-1α

Chronic inflammation leads to the formation of a pro-tumorigenic microenvironment that can promote tumor development, growth and differentiation through augmentation of tumor angiogenesis. Prostate cancer (CaP) risk and prognosis are adversely correlated with a number of inflammatory and angiogenic mediators, including Toll-like receptors (TLRs), NF-κB and vascular endothelial growth factor (VEGF). Peroxiredoxin 1 (Prx1) was recently identified as an endogenous ligand for TLR4 that is secreted from CaP cells and promotes inflammation. Inhibition of Prx1 by CaP cells resulted in reduced expression of VEGF, diminished tumor vasculature and retarded tumor growth. The mechanism by which Prx1 regulates VEGF expression in normoxic conditions was investigated in the current study. Our results show that incubation of mouse vascular endothelial cells with recombinant Prx1 caused increases in VEGF expression that was dependent upon TLR4 and required hypoxia inducible factor-1 (HIF-1) interaction with the VEGF promoter. The induction of VEGF was also dependent upon NF-κB; however, NF-κB interaction with the VEGF promoter was not required for Prx1 induction of VEGF suggesting that NF-κB was acting indirectly to induce VEGF expression. The results presented here show that Prx1 stimulation increased NF-κB interaction with the HIF-1α promoter, leading to enhanced promoter activity and increases in HIF-1α mRNA levels, as well as augmented HIF-1 activity that resulted in VEGF expression. Prx1 induced HIF-1 also promoted NF-κB activity, suggesting the presence of a positive feedback loop that has the potential to perpetuate Prx1 induction of angiogenesis. Strikingly, inhibition of Prx1 expression in CaP was accompanied with reduced expression of HIF-1α. The combined findings of the current study and our previous study suggest that Prx1 interaction with TLR4 promotes CaP growth potentially through chronic activation of tumor angiogenesis.

IκB kinases modulate the activity of the androgen receptor in prostate carcinoma cell lines

Enhanced nuclear localization of nuclear factor κB (NF-κB) in prostate cancer (PCa) samples and constitutive NF-κB signaling in a class of PCa cell lines with low androgen receptor (AR) expression (PC3 and DU-145) imply an important role of the IκB kinase (IKK)/NF-κB system in PCa. However, most PCa and PCa cell lines depend on the activity of the AR, and the role of NF-κB in these AR-expressing PCa remains unclear. Here, we demonstrate that inhibition of NF-κB signaling by the IKK inhibitor BMS345541 reduced proliferation and increased apoptosis in AR-expressing PCa cell lines. Furthermore, AR activity and target gene expression were distinctively reduced, whereas AR protein levels remained unaltered on BMS345541 treatment. Similar effects were observed particularly after small interfering RNA (siRNA)-mediated knockdown of IKK1, but not by siRNA-mediated suppression of IKK2. Moreover, IKK1 overexpression augmented 5α-dihydrotestosterone-induced nuclear AR translocation, whereas nuclear AR was reduced by IKK1 knockdown or BMS345541. However, because IKK1 also enhances the activity of a chronically nuclear AR mutant, modulation of the subcellular distribution seems not to be the only mechanism by which IKK1 enhances AR activity. Finally, reduced in vivo AR phosphorylation after BMS345541 treatment and in vitro AR phosphorylation by IKK1 or IKK2 imply that AR constitutes a novel IKK target. Taken together, our data identify IKK1 as a potentially target structure for future therapeutic intervention in PCa.

Complementary and alternative medicines in prostate cancer: from bench to bedside?

Complementary and alternative medicine (CAM) use is common among adults, and recent reports suggest that 25%-50% of prostate cancer (PCa) patients use at least one CAM modality. The most common CAM modalities used by PCa patients are vitamin and herbal preparations with purported antitumor effects despite only modest underlying preclinical or clinical evidence of efficacy. In this review we provide a brief overview of the basic scientific and clinical studies underlying the most common herbal and vitamin preparations including common antioxidants, pomegranate extract, green tea, turmeric, resveratrol, silibinin, and herbal combination preparations. When available, prostate cancer clinical trial data are reviewed. Importantly, we have compared the concentration of these agents used in in vitro experiments to that likely to be achievable in humans. From the available data we conclude that there is insufficient evidence to support the use of CAMs for the treatment of prostate cancer patients outside of a clinical trial. The purpose of this review is to more rigorously evaluate CAM therapy in prostate cancer and educate oncologists and patients. This review focuses on examples from the general classes of agents in common use.