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

Expression of neutral endopeptidase, endothelin-1, and nuclear factor kappa B in prostate cancer: interrelations and associations with prostate-specific antigen recurrence after radical prostatectomy

Objective. To study the impact of the neutral endopeptidase (NEP)/neuropeptides (NPs) axis and nuclear factor kappa B (NFκB) as predictors of prostate-specific antigen (PSA) recurrence after radical prostatectomy (RP). Patients and Methods. 70 patients with early-stage PC were treated with RP and their tumor samples were evaluated for expression of NEP, endothelin-1 (ET-1) and NFκB (p65). Time to PSA recurrence was correlated with the examined parameters and combined with preoperative PSA level, Gleason score, pathological TNM (pT) stage, and surgical margin (SM) assessment. Results and Limitations. Membranous expression of NEP (P < 0.001), cytoplasmic ET-1 (P = 0.002), and cytoplasmic NFκB (P < 0.001) were correlated with time to PSA relapse. NEP was associated with ET-1 (P < 0.001) and NFκB (P < 0.001). ET-1 was also correlated with NFκB (P < 0.001). NEP expression (P = 0.017), pT stage (P = 0.013), and SMs (P = 0.036) were independent predictors of time to PSA recurrence. Conclusions. There seems to be a clinical model of NEP/NPs and NFκB pathways interconnection, with their constituents following inverse patterns of expression in accordance with their biological roles and molecular interrelations.

CD10 is inversely associated with nuclear factor-kappa B and predicts biochemical recurrence after radical prostatectomy

INTRODUCTION

The cell surface endopeptidase CD10 (neutral endopeptidase) and nuclear factor-κB (NF-κB) have been independently associated with prostate cancer (PC) progression. We investigated the correlations between these two factors and their prognostic relevance in terms of biochemical (prostate-specific antigen, PSA) relapse after radical prostatectomy (RP) for localized PC.

PATIENTS AND METHODS

The immunohistochemical expression of CD10 and NF-κB in samples from 70 patients who underwent RP for localized PC was correlated with the preoperative PSA level, Gleason score, pathological stage and time to PSA failure.

RESULTS

CD10 expression was inversely associated with NF-κB expression (p < 0.001), stage (p = 0.03) and grade (p = 0.003), whereas NF-κB was directly related with stage (p = 0.006) and grade (p = 0.002). The median time to PSA failure was 56 months. CD10 and NF-κB were directly (p < 0.001) and inversely (p < 0.001) correlated with biochemical recurrence-free survival, respectively. CD10 expression (p = 0.022) and stage (p = 0.018) were independently associated with time to biochemical recurrence.

CONCLUSION

Low CD10 expression is an adverse prognostic factor for biochemical relapse after RP in localized PC, which is also associated with high NF-κB expression. Decreased CD10 expression which would lead to increased neuropeptide signaling and NF-κB activity may be present in a subset of early PCs.

Dietary energy balance modulates prostate cancer progression in Hi-Myc mice

Male Hi-Myc mice were placed on three dietary regimens [30% calorie restriction (CR), overweight control (modified AIN76A with 10 kcal% fat), and a diet-induced obesity regimen (DIO) 60 kcal% fat]. All diet groups had approximately similar incidence of hyperplasia and low-grade prostatic intraepithelial neoplasia in the ventral prostate at 3 and 6 months of age. However, 30% CR significantly reduced the incidence of in situ adenocarcinomas at 3 months compared with the DIO group and at 6 months compared with both the overweight control and DIO groups. Furthermore, the DIO regimen significantly increased the incidence of adenocarcinoma with aggressive stromal invasion, as compared with the overweight control group (96% vs. 65%, respectively; P = 0.02) at the 6-month time point. In addition, at both 3 and 6 months, only in situ carcinomas were observed in mice maintained on the 30% CR diet. Relative to overweight control, DIO increased whereas 30% CR reduced activation of Akt, mTORC1, STAT3, and NFκB (p65) in ventral prostate. DIO also significantly increased (and 30% CR decreased) numbers of T-lymphocytes and macrophages in the ventral prostate compared with overweight control. The mRNA levels for interleukin (IL) 1α, IL1β, IL6, IL7, IL23, IL27, NFκB1 (p50), TNFα, and VEGF family members were significantly increased in the ventral prostate of the DIO group compared with both the overweight control and 30% CR diet groups. Collectively, these findings suggest that enhanced growth factor (Akt/mTORC1 and STAT3) and inflammatory (NFκB and cytokines) signaling may play a role in dietary energy balance effects on prostate cancer progression in Hi-Myc mice.

NF-κB signaling in prostate cancer: a promising therapeutic target?

Prostate carcinoma (PCa) displays a wide variety of genetic alterations, versatile expression profiles as well as cell surface markers. Despite this heterogeneity, a common treatment for advanced PCa is androgen deprivation therapy (ADT). ADT targets the androgen receptor-a member of the nuclear receptor superfamily-which is required for development and function of the prostate and critical for PCa growth and survival. After an initial regression of the tumor during ADT, a large fraction of tumors progress to so-called castration-resistant prostate carcinoma (CRPca) which is highly resistant toward chemotherapy. The ensuing high mortality rates illustrate the importance of novel therapeutic targets for CRPCa. The transcription factor NF-κB was recently proposed as such a potential target for therapeutic intervention in CRPCa. Although NF-κB is essential for the regulation of innate and adaptive immunity recent data suggest a role of NF-κB in cancer initiation and progression. However, the exact function of NF-κB signaling in PCa is still a matter of debate. Here, we review known roles of NF-κB signaling in PCa and emphasize the crosstalk of NF-κB and androgen receptor signaling. Finally, we discuss potential therapeutic relevance of blocking NF-κB in PCa.

IκB-Kinase-ε (IKKε/IKKi/IκBKε) expression and localization in prostate cancer tissues

BACKGROUND

Advanced prostate cancer (PCa) remains a one of the leading causes of cancer related death and is often due to the progression from a hormone sensitive (HS) to a castrate resistant (CR) state for which therapeutic alternatives remain palliative. Molecular events involved in the progression to CR-PCa remain largely unknown. A previous study reported significantly higher levels of Iκ-B kinase-epsilon (IKKε) expression in CR compared to androgen-responsive cell lines. In the present study, we evaluate IKKε expression in human prostate tissue.

METHODS

In order to evaluate the modulation of IKKε expression in PCa tissue IKKε immunostaining was performed on paraffin-embedded prostate tissue microarrays containing cores from normal tissues (n = 47), non-malignant tissues adjacent to the tumor (n = 53), prostatic intraepithelial neoplasia (PIN) (n = 28), HS (n = 62), and CR tumors (n = 31).

RESULTS

We found a low cytoplasmic expression of IKKε in non-malignant tissue. HS tumors showed a significant increase in cytoplasmic IKKε expression compared to non-malignant tissues. CR tissues presented the highest cytoplasmic IKKε expression levels. We also report, for the first time, the presence of a nuclear localization of IKKε in prostate epithelial cells, in particular we observed an increase of IKKε nuclear localization in HS malignant tissues. Finally, we found a strong link between an increase of IKKε cytoplasmic expression in PCa and metastatic progression.

CONCLUSION

This study strongly suggests the role of IKKε as a PCa oncogene that may be involved in the emergence of a CR state.

Anti-cancer effect of bee venom in prostate cancer cells through activation of caspase pathway via inactivation of NF-κB

BACKGROUND

Bee venom has been used as a traditional medicine to treat arthritis, rheumatism, back pain, cancerous tumors, and skin diseases. However, the effects of bee venom on the prostate cancer and their action mechanisms have not been reported yet.

METHODS

To determine the effect of bee venom and its major component, melittin on the prostate cancer cells, apoptosis is analyzed by tunnel assay and apoptotic gene expression. For xenograft studies, bee venom was administrated intraperitoneally twice per week for 4 weeks, and the tumor growth was measured and the tumor were analyzed by immunohistochemistry. To investigate whether bee venom and melittin can inactivate nuclear factor kappa B (NF-κB), we assessed NF-κB activity in vitro and in vivo.

RESULTS AND CONCLUSIONS

Bee venom (1-10 µg/ml) and melittin (0.5-2.5 µg/ml) inhibited cancer cell growth through induction of apoptotic cell death in LNCaP, DU145, and PC-3 human prostate cancer cells. These effects were mediated by the suppression of constitutively activated NF-κB. Bee venom and melittin decreased anti-apoptotic proteins but induced pro-apoptotic proteins. However, pan caspase inhibitor abolished bee venom and melittin-induced apoptotic cell death and NF-κB inactivation. Bee venom (3-6 mg/kg) administration to nude mice implanted with PC-3 cells resulted in inhibition of tumor growth and activity of NF-κB accompanied with apoptotic cell death. Therefore, these results indicated that bee venom and melittin could inhibit prostate cancer in in vitro and in vivo, and these effects may be related to NF-κB/caspase signal mediated induction of apoptotic cell death.

Alpha-tomatine induces apoptosis and inhibits nuclear factor-kappa B activation on human prostatic adenocarcinoma PC-3 cells

Background

Alpha-tomatine (α-tomatine) is the major saponin in tomato (Lycopersicon esculentum). This study investigates the chemopreventive potential of α-tomatine on androgen-independent human prostatic adenocarcinoma PC-3 cells.

Methodology/Principal Findings

Treatment of highly aggressive human prostate cancer PC-3 cells with α-tomatine resulted in a concentration-dependent inhibition of cell growth with a half-maximal efficient concentration (EC₅₀) value of 1.67±0.3 µM. It is also less cytotoxic to normal human liver WRL-68 cells and normal human prostate RWPE-1 cells. Assessment of real-time growth kinetics by cell impedance-based Real-Time Cell Analyzer (RTCA) showed that α-tomatine exhibited its cytotoxic effects against PC-3 cells as early as an hour after treatment. The inhibitory effect of α-tomatine on PC-3 cancer cell growth was mainly due to induction of apoptosis as evidenced by positive Annexin V staining and decreased in mitochondrial membrane potential but increased in nuclear condensation, polarization of F-actin, cell membrane permeability and cytochrome c expressions. Results also showed that α-tomatine induced activation of caspase-3, -8 and -9, suggesting that both intrinsic and extrinsic apoptosis pathways are involved. Furthermore, nuclear factor-kappa B (NF-κB) nuclear translocation was inhibited, which in turn resulted in significant decreased in NF-κB/p50 and NF-κB/p65 in the nuclear fraction of the treated cells compared to the control untreated cells. These results provide further insights into the molecular mechanism of the anti-proliferative actions of α-tomatine.

Conclusion/Significance

α-tomatine induces apoptosis and inhibits NF-κB activation on prostate cancer cells. These results suggest that α-tomatine may be beneficial for protection against prostate cancer development and progression.

Tumour-initiating stem-like cells in human prostate cancer exhibit increased NF-κB signalling

Androgen depletion is a key strategy for treating human prostate cancer, but the presence of hormone-independent cells escaping treatment remains a major therapeutic challenge. Here, we identify a minor subset of stem-like human prostate tumour-initiating cells (TICs) that do not express prostate cancer markers, such as androgen receptor or prostate specific antigen. These TICs possess stem cell characteristics and multipotency as demonstrated by in vitro sphere-formation and in vivo tumour-initiation, respectively. The cells represent an undifferentiated subtype of basal cells and can be purified from prostate tumours based on coexpression of the human pluripotent stem cell marker TRA-1-60 with CD151 and CD166. Such triple-marker-positive TICs recapitulate the original parent tumour heterogeneity in serial xeno-transplantations indicating a tumour cell hierarchy in human prostate cancer development. These TICs exhibit increased nuclear factor-κB activity. These findings are important in understanding the molecular basis of human prostate cancer.

Tumours consist of heterogeneous cell types that respond differently to treatment. Here, on the basis of the expression of three different proteins, the authors describe a subset of prostate cancer cells that have stem cell-like properties that are able to initiate tumour formation in vivo.

[Prostate specific antigen and NF-kB in prostatic disease: relation with malignancy]

INTRODUCTION

NF-kB (p50/p65) is a transcription factor involved in TNF-α-induced cell death resistance by promoting several antiapoptotic genes. We intend to relate the expression of NF-kB (p50 and p65) with serum levels of prostate-specific antigen (PSA), both in normal males and in those with pathologic conditions of the prostate.

MATERIALS AND METHODS

this study was carried out in 5 normal, 24 benign prostatic hyperplastic (BPH) and 19 patients with prostate cancer (PC). Immunohistochemical and Western blot analyses were performed on tissue and serum PSA was assayed by PSA DPC Immulite assays (Diagnostics Products Corporation, Los Angeles, CA).

RESULTS

in controls, p65 NF-kB was not found and p50 was scantly detected in 60% normal samples in the cytoplasm of epithelial cells. Both p50 and p65 were expressed in 62.5% of the samples with BPH and in 63.2% of those with PC. Both increased its frequency of expression with higher PSA serum levels.

CONCLUSIONS

Activation of NF-kB revealed by its nuclear translocation in prostate cancer could be related to cancer progression and elevated seric PSA levels. A better understanding of the biologic mechanism by which circulating PSA levels increase and its relation with NF-kB expression is needed. Possibly, NF-kB blockage could be used as a therapeutic target to counteract proliferation in prostate cancer.

Activation of NF-{kappa}B by TMPRSS2/ERG Fusion Isoforms through Toll-Like Receptor-4

The TMPRSS2/ERG (T/E) fusion gene is present and thought to be an oncogenic driver of approximately half of all prostate cancers. Fusion of the androgen-regulated TMPRSS2 promoter to the ERG oncogene results in constitutive high level expression of ERG which promotes prostate cancer invasion and proliferation. Here, we report the characterization of multiple alternatively spliced T/E fusion gene isoforms which have differential effects on invasion and proliferation. We found that T/E fusion gene isoforms differentially increase NF-κB-mediated transcription, which may explain in part the differences in biological activities of the T/E fusion isoforms. This increased activity is due to phosphorylation of NF-κB p65 on Ser536. Tissue microarray immunochemistry revealed that p65 phospho-Ser536 is present in the majority of prostate cancers where it is associated with ERG protein expression. The T/E fusion gene isoforms differentially increase expression of a number of NF-κB associated genes including PAR1, CCL2, FOS, TLR3, and TLR4 (Toll-like receptor). TLR4 activation is known to promote p65 Ser536 phosphorylation and knockdown of TLR4 with shRNA decreases Ser536 phosphorylation in T/E fusion gene expressing cells. TLR4 can be activated by proteins in the tumor microenvironment and lipopolysacharide from Gram (-) bacteria. Our findings suggest that bacterial infection of the prostate and/or endogenous microenvironment proteins may promote progression of high-grade prostatic intraepithelial neoplasia and/or prostate cancers that express the T/E fusion gene, where the NF-κB pathway might be targeted as a rational therapeutic approach.

Molecular genetics of prostate cancer: new prospects for old challenges

Despite much recent progress, prostate cancer continues to represent a major cause of cancer-related mortality and morbidity in men. Since early studies on the role of the androgen receptor that led to the advent of androgen deprivation therapy in the 1940s, there has long been intensive interest in the basic mechanisms underlying prostate cancer initiation and progression, as well as the potential to target these processes for therapeutic intervention. Here, we present an overview of major themes in prostate cancer research, focusing on current knowledge of principal events in cancer initiation and progression. We discuss recent advances, including new insights into the mechanisms of castration resistance, identification of stem cells and tumor-initiating cells, and development of mouse models for preclinical evaluation of novel therapuetics. Overall, we highlight the tremendous research progress made in recent years, and underscore the challenges that lie ahead.

Diagnostic biomarkers of prostate cancer

OBJECTIVE

Diagnostic tissue biomarkers for prostate cancer (PC) include basal cell markers and α-methylacyl-coenzyme A-racemase (AMACR), often used in combination. Their sensitivity and specificity are not perfect and there is a need for additional diagnostic biomarkers for PC in cases that are difficult to diagnose on routine stained sections.

MATERIAL AND METHODS

This study investigated the diagnostic accuracy of three novel tissue biomarkers for PC found through a search in the Human Protein Atlas database ( www.proteinatlas.com ): somatic cytochrome c (CYCS), intestinal cell kinase (ICK) and inhibitor of nuclear factor-κB kinase subunit beta (IKBKB), and compared the results with AMACR. A tissue microarray was constructed from 40 consecutive radical prostatectomy (RP) specimens including benign prostatic tissue, atrophy, high-grade prostatic intraepithelial neoplasia (HGPIN) and PC. Immunoreactivity was scored based on staining intensity and extent. Real-time polymerase chain reaction (PCR) was performed on malignant and benign frozen tissue samples from 32 RP specimens.

RESULTS

All four biomarkers showed a stronger expression in PC and HGPIN than in benign tissue (p < 0.001). The highest diagnostic accuracy for PC was achieved with ICK and AMACR at 97%. The area under the curve for CYCS, ICK, IKBKB and AMACR was 0.859, 0.997, 0.865 and 0.983, respectively. The presence of mRNA transcripts of the genes was confirmed by real-time PCR in benign and malignant prostatic tissue.

CONCLUSIONS

AMACR is an accurate diagnostic tissue marker for PC. However, in some PCs AMACR is false negative and a panel of CYCS, ICK and IKBKB may serve as ancillary diagnostic tool.

Cancer biomarker discovery: the entropic hallmark

Background

It is a commonly accepted belief that cancer cells modify their transcriptional state during the progression of the disease. We propose that the progression of cancer cells towards malignant phenotypes can be efficiently tracked using high-throughput technologies that follow the gradual changes observed in the gene expression profiles by employing Shannon's mathematical theory of communication. Methods based on Information Theory can then quantify the divergence of cancer cells' transcriptional profiles from those of normally appearing cells of the originating tissues. The relevance of the proposed methods can be evaluated using microarray datasets available in the public domain but the method is in principle applicable to other high-throughput methods.

Methodology/Principal Findings

Using melanoma and prostate cancer datasets we illustrate how it is possible to employ Shannon Entropy and the Jensen-Shannon divergence to trace the transcriptional changes progression of the disease. We establish how the variations of these two measures correlate with established biomarkers of cancer progression. The Information Theory measures allow us to identify novel biomarkers for both progressive and relatively more sudden transcriptional changes leading to malignant phenotypes. At the same time, the methodology was able to validate a large number of genes and processes that seem to be implicated in the progression of melanoma and prostate cancer.

Conclusions/Significance

We thus present a quantitative guiding rule, a new unifying hallmark of cancer: the cancer cell's transcriptome changes lead to measurable observed transitions of Normalized Shannon Entropy values (as measured by high-througput technologies). At the same time, tumor cells increment their divergence from the normal tissue profile increasing their disorder via creation of states that we might not directly measure. This unifying hallmark allows, via the the Jensen-Shannon divergence, to identify the arrow of time of the processes from the gene expression profiles, and helps to map the phenotypical and molecular hallmarks of specific cancer subtypes. The deep mathematical basis of the approach allows us to suggest that this principle is, hopefully, of general applicability for other diseases.

Chemosensitization in non-small cell lung cancer cells by IKK inhibitor occurs via NF-kappaB and mitochondrial cytochrome c cascade

In this study, we demonstrated with mechanistic evidence that parthenolide, a sesquiterpene lactone, could antagonize paclitaxel-mediated NF-κB nuclear translocation and activation by selectively targeting I-κB kinase (IKK) activity. We also found that parthenolide could target IKK activity and then inhibit NF-κB; this promoted cytochrome c release and activation of caspases 3 and 9. Inhibition of caspase activity blocked the activation of caspase cascade, implying that the observed synergy was related to caspases 3 and 9 activation of parthenolide. In contrast, paclitaxel individually induced apoptosis via a pathway independent of the mitochondrial cytochrome c cascade. Finally, exposure to parthenolide resulted in the inhibition of several NF-κB transcript anti-apoptotic proteins such as c-IAP1 and Bcl-xl. These data strengthen the rationale for using parthenolide to decrease the apoptotic threshold via caspase-dependent processes for treatment of non-small cell lung cancer with paclitaxel chemoresistance.

Nuclear factor-κB expression is predictive of overall survival in patients with cutaneous melanoma

Nuclear factor (NF)- κB is one of the most important transcription factors that plays a crucial role in the regulation of a wide spectrum of genes involved in modulating the cell cycle, apoptosis, cell growth, angiogenesis, inflammation and the tissue invasiveness of highly malignant cells. NF-κB activity has been found to be constitutively elevated in a number of human tumors from either a haematological or solid origin, such as melanomas. In several studies, NF-κB activation was shown to be an adverse prognostic factor, and in melanoma it was proposed as an event that promotes tumor progression. This study aimed to evaluate whether NF-κB activation in tumor tissues, assessed by the expression of the NF-κB p65 subunit, has an effect on the survival of melanoma patients. The expression of NF-κB was immunohistochemically investigated, and the correlation with survival was analyzed. Furthermore, the immunostaining for p53 and survivin was evaluated, and the relationship of these apoptotic and anti-apoptotic factors with NF-κB expression was analyzed. Kaplan-Meier analysis showed that patients with low levels of NF-κB in the nuclei of tumor cells had a significantly longer survival compared to those with high levels. Multivariate analysis confirmed the predictive value of nuclear NF-κB, showing that its expression maintains significance after the model was adjusted using clinicopathological factors. The results demonstrate the correlation of NF-κB p65 nuclear staining with the disease-specific 5-year survival of melanoma patients and suggest that nuclear NF-κB p65 may be promising as an early independent prognostic factor in patients with primary cutaneous melanoma.

Multicenter clinical validation of PITX2 methylation as a prostate specific antigen recurrence predictor in patients with post-radical prostatectomy prostate cancer

PURPOSE

Radical prostatectomy is potentially curative in patients with clinically localized prostate cancer. However, biochemical recurrence affects 15% to 30% of men who undergo radical prostatectomy. We previously reported the prognostic potential of PITX2 gene promoter methylation using conventional assays. In the current study we validated PITX2 methylation status as a biochemical recurrence predictor after radical prostatectomy using a novel microarray based platform in a multi-institutional setting.

MATERIALS AND METHODS

PITX2 methylation status was assessed in formalin fixed, paraffin embedded prostatectomy tumor tissue samples from 476 patients from a total of 4 institutions on customized EpiChip PITX2 microarrays. Associations between PITX2 methylation and biochemical recurrence were assessed using the log rank test and Cox regression controlling for prostate cancer features.

RESULTS

On multivariate analysis men with high methylation status were at significantly higher risk for biochemical recurrence than those with low methylation status (HR 3.0, 95% CI 2.0-4.5, p <10(-5)). The biochemical recurrence-free survival rate 5 years after surgery was 85% and 61% in the low and high methylation groups, respectively. In men with pathological Gleason 7 tumors the relative risk of biochemical recurrence was twice as high for high than for low PITX2 methylation (HR 2.0, 95% CI 1.2-3.3, p = 0.005).

CONCLUSIONS

PITX2 methylation status assessed by EpiChip PITX2 identifies patients with prostate cancer who are most likely to have biochemical recurrence. This test independently adds to the prognostic information provided by standard clinicopathological analysis, improving prostatectomy case stratification into those at high and low risk for biochemical recurrence. This new clinical tool would be of particular benefit to assess intermediate risk cases (Gleason 7) in which risk stratification remains a challenge.

Expression of nuclear transcription factor kappa B in locally advanced human cervical cancer treated with definitive chemoradiation

PURPOSE

Nuclear factor kappa B (NF-κB), a transcriptional factor that has been shown to be constitutively active in cervical cancer, is part of an important pathway leading to treatment resistance in many tumor types. The purpose of our study was to determine whether expression of NF-κB in pretreatment specimens and specimens taken shortly after treatment initiation correlated with outcome in cervical cancer patients treated with definitive chemoradiation.

METHODS AND MATERIALS

Eighteen patients with locally advanced cervical cancer were enrolled in a study in which cervical biopsy specimens were obtained before radiation therapy and 48 h after treatment initiation. Matched biopsy specimens from 16 of these patients were available and evaluated for the nuclear expression of NF-κB protein by immunohistochemical staining.

RESULTS

After a median follow-up of 43 months, there were 9 total treatment failures. Nuclear staining for NF-κB was positive in 3 of 16 pretreatment biopsy specimens (19%) and 5 of 16 postradiation biopsy specimens (31%). Pretreatment expression of NF-κB nuclear staining correlated with increased rates of local-regional failure (100% vs. 23%, p = 0.01), distant failure (100% vs. 38%, p = 0.055), disease-specific mortality (100% vs. 31%, p = 0.03), and overall mortality (100% vs. 38%, p = 0.055).

CONCLUSIONS

Our data suggest that pretreatment nuclear expression of NF-κB may be associated with a poor outcome for cervical cancer patients treated with chemoradiation. Although these data require validation in a larger group of patients, the results support the continued study of the relationship between NF-κB and outcome in patients treated for carcinoma of the cervix.

Increased prevalence of insulin resistance in patients with differentiated thyroid carcinoma

BACKGROUND

Patients with insulin resistance (IR) have a higher prevalence of thyroid nodules. In the present study, we present original data showing that patients with differentiated thyroid carcinoma (DTC) also have a higher frequency of IR.

METHODS

Twenty women with DTC (group 1, G1) and 20 euthyroid individuals (control group, CG) were investigated for IR. G1 and CG subjects were matched in pairs by age, gender, and body mass index (BMI). The diagnosis of IR was made when the homeostasis model assesment of insulin resistance (HOMA-IR) index was higher than 2.5. According to the BMI, 20 women (10 with DTC and 10 of the CG) had a BMI < 25, whereas the other 20 had higher BMI values (overweight and obese patients).

RESULTS

IR was present in the 50% of G1, but only in the 10% of the CG (P < 0.001). In the groups with lower BMI (<25), we found IR in 30% of G1 and no cases in the CG, whereas in those with BMI > 25 the IR was present in 70% of G1 and 20% of CG. There were no differences between the two subgroups regarding the time in which the IR tests were performed. IR was present in 56.3% of patient with papillary anol 25% of follicular thyroid carcinomas, respectively.

CONCLUSIONS

We conclude that such a high prevalence of IR would be an important risk factor for developing DTC, as it is well known with some other nonthyroid carcinomas.

Inhibition of constitutive and cxc-chemokine-induced NF-kappaB activity potentiates ansamycin-based HSP90-inhibitor cytotoxicity in castrate-resistant prostate cancer cells

Background:

We determined how CXC-chemokine signalling and necrosis factor-κB (NF-κB) activity affected heat-shock protein 90 (Hsp90) inhibitor (geldanamycin (GA) and 17-allylamino-demethoxygeldanamycin (17-AAG)) cytotoxicity in castrate-resistant prostate cancer (CRPC).

Methods:

Geldanamycin and 17-AAG toxicity, together with the CXCR2 antagonist AZ10397767 or NF-κB inhibitor BAY11-7082, was assessed by 3-(4, 5-Dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide assay in two CRPC lines, DU145 and PC3. Flow cytometry quantified apoptotic or necrosis profiles. Necrosis factor-κB activity was determined by luciferase readouts or indirectly by quantitative PCR and ELISA-based determination of CXCL8 expression.

Results:

Geldanamycin and 17-AAG reduced PC3 and DU145 cell viability, although PC3 cells were less sensitive. Addition of AZ10397767 increased GA (e.g., PC3 IC₂₀: from 1.67±0.4 to 0.18±0.2 nM) and 17-AAG (PC3 IC₂₀: 43.7±7.8 to 0.64±1.8 nM) potency in PC3 but not DU145 cells. Similarly, BAY11-7082 increased the potency of 17-AAG in PC3 but not in DU145 cells, correlating with the elevated constitutive NF-κB activity in PC3 cells. AZ10397767 increased 17-AAG-induced apoptosis and necrosis and decreased NF-κB activity/CXCL8 expression in 17-AAG-treated PC3 cells.

Conclusion:

Ansamycin cytotoxicity is enhanced by inhibiting NF-κB activity and/or CXC-chemokine signalling in CRPC cells. Detecting and/or inhibiting NF-κB activity may aid the selection and treatment response of CRPC patients to Hsp90 inhibitors.

Inflammation and cancer: how friendly is the relationship for cancer patients?

Evidence has emerged in the last two decades that at the molecular level most chronic diseases, including cancer, are caused by a dysregulated inflammatory response. The identification of transcription factors such as NF-kappaB, AP-1 and STAT3 and their gene products such as tumor necrosis factor, interleukin-1, interleukin-6, chemokines, cyclooxygenase-2, 5 lipooxygenase, matrix metalloproteases, and vascular endothelial growth factor, adhesion molecules and others have provided the molecular basis for the role of inflammation in cancer. These inflammatory pathways are activated by tobacco, stress, dietary agents, obesity, alcohol, infectious agents, irradiation, and environmental stimuli, which together account for as much as 95% of all cancers. These pathways have been implicated in transformation, survival, proliferation, invasion, angiogenesis, metastasis, chemoresistance, and radioresistance of cancer, so much so that survival and proliferation of most types of cancer stem cells themselves appear to be dependent on the activation of these inflammatory pathways. Most of this evidence, however, is from preclinical studies. Whether these pathways have any role in prevention, progression, diagnosis, prognosis, recurrence or treatment of cancer in patients, is the topic of discussion of this review. We present evidence that inhibitors of inflammatory biomarkers may have a role in both prevention and treatment of cancer.

NF-kappaB regulates androgen receptor expression and prostate cancer growth

Prostate cancers that progress during androgen-deprivation therapy often overexpress the androgen receptor (AR) and depend on AR signaling for growth. In most cases, increased AR expression occurs without gene amplification and may be due to altered transcriptional regulation. The transcription factor nuclear factor (NF)-kappaB, which is implicated in tumorigenesis, functions as an important downstream substrate of mitogen-activated protein kinase, phosphatidylinositol 3-kinase, AKT, and protein kinase C and plays a role in other cancer-associated signaling pathways. NF-kappaB is an important determinant of prostate cancer clinical biology, and therefore we investigated its role in the regulation of AR expression. We found that NF-kappaB expression in prostate cancer cells significantly increased AR mRNA and protein levels, AR transactivation activity, serum prostate-specific antigen levels, and cell proliferation. NF-kappaB inhibitors decrease AR expression levels, prostate-specific antigen secretion, and proliferation of prostate cancer cells in vitro. Furthermore, inhibitors of NF-kappaB demonstrated anti-tumor activity in androgen deprivation-resistant prostate cancer xenografts. In addition, levels of both NF-kappaB and AR were strongly correlated in human prostate cancer. Our data suggest that NF-kappaB can regulate AR expression in prostate cancer and that NF-kappaB inhibitors may have therapeutic potential.

Nuclear factor-kappaB inhibition by parthenolide potentiates the efficacy of Taxol in non-small cell lung cancer in vitro and in vivo

In this study, we have examined the molecular events induced by parthenolide, a sesquiterpene lactone, and explored possible mechanisms of resistance and sensitization of tumor cells to Taxol. We showed that parthenolide could antagonize Taxol-mediated nuclear factor-kappaB (NF-kappaB) nuclear translocation and activation and Bcl-xl up-regulation by selectively targeting I-kappaB kinase activity. In A549 cells, inhibition of nuclear factor-kappaB by parthenolide resulted in activation of the mitochondrial death pathway to promote cytochrome c release and caspase 3 and 9 activation. In contrast, Taxol alone induced apoptosis via a pathway independent of mitochondria cytochrome c cascade. In addition, depletion of Bcl-xl rescued the apoptotic response to Taxol. Moreover, treatment with parthenolide increased the efficacy of the Taxol-induced inhibition of A549 tumor xenografts in mice. This study elucidated the cellular responses induced by parthenolide that decrease the threshold of mitochondria-dependent apoptosis in the treatment of non-small cell lung cancer cells.

Characterization of the intra-prostatic immune cell infiltration in androgen-deprived prostate cancer patients

INTRODUCTION

Our goal was to study the hormonal regulation of immune cell infiltration in prostate cancer patients treated by androgen deprivation therapy (ADT) using an optimized computer-assistance quantification approach.

METHODS

The relative density of immune cell subtypes (CD3(+), CD8(+), CD20(+), CD56(+), CD68(+) and Foxp3(+)) was analyzed by immunohistochemistry in archived prostate specimens from control patients (radical prostatectomy only, n=40) and ADT-treated patients (ADT prior to radical prostatectomy, n=35) using an image analysis software and a whole-slide scanner.

RESULTS

ADT-treated patients had significantly increased relative density of CD3(+) (p<0.001) and CD8(+) T lymphocytes (p<0.001) as well as CD68(+) macrophages (p<0.001). Elevated abundance of CD56(+) Natural Killer (NK) cells was associated with a lower risk of prostate cancer progression (p=0.044), while a high density of CD68(+) macrophages was related to an increased risk of biochemical recurrence (p=0.011).

CONCLUSIONS

Our results demonstrate that the infiltration of specific immune cell subtypes is modulated by ADT. Furthermore our data confirm that NK cells have a protective role against tumor progression while macrophages seem to favor the development of advanced prostate cancer.

Over-expression of IkappaB-kinase-epsilon (IKKepsilon/IKKi) induces secretion of inflammatory cytokines in prostate cancer cell lines

BACKGROUND

Elevated inflammatory cytokine levels in serum have been associated with advanced stage metastasis-related morbidity in prostate cancer. Several studies have shown that IL-6 and IL-8 can accelerate the growth of human prostate cancer cell lines. Previous studies, in murine embryonic fibroblasts, have shown that Ikappa-B kinase-epsilon (IKKepsilon/IKKi)-deficiency results in the reduction of lipopolysaccharide-mediated expression of IL-6.

RESULTS

In this study, we report that over-expression of IKKepsilon in hormone-sensitive 22Rv1 and LNCaP prostate cancer cells induces the secretion of several inflammatory cytokines including IL-6 and IL-8. Both of these cytokines are secreted by hormone-refractory PC-3 prostate cancer cells and IKKepsilon knock-down in these cells correlates with a strong decrease in IL-6 secretion. Furthermore, we demonstrate that IKKepsilon over-expression does not induce the activation of the IKKepsilon classical targets NF-kappaB and IRF-3, two transcription factors involved in the regulation of several cytokines. Finally, we observe that high IKKepsilon expression results in its nuclear translocation, a phenomena that is TBK1-independent.

CONCLUSIONS

This study identifies IKKepsilon as a potential prostate cancer gene that may favor chronic inflammation and create a tumor-supporting microenvironment that promotes prostate cancer progression, particularly by the induction of IL-6 secretion that may act as a positive growth factor in prostate cancer.

GGAP2/PIKE-a directly activates both the Akt and nuclear factor-kappaB pathways and promotes prostate cancer progression

GGAP2/PIKE-A is a GTP-binding protein that can enhance Akt activity. Increased activation of the AKT and nuclear factor-kappaB (NF-kappaB) pathways have been identified as critical steps in cancer initiation and progression in a variety of human cancers. We have found significantly increased expression GGAP2 in the majority of human prostate cancers and GGAP2 expression increases Akt activation in prostate cancer cells. Thus, increased GGAP2 expression is a common mechanism for enhancing the activity of the Akt pathway in prostate cancers. In addition, we have found that activated Akt can bind and phosphorylate GGAP2 at serine 629, which enhances GTP binding by GGAP2. Phosphorylated GGAP2 can bind the p50 subunit of NF-kappaB and enhances NF-kappaB transcriptional activity. When expressed in prostate cancer cells, GGAP2 enhances proliferation, foci formation, and tumor progression in vivo. Thus, increased GGAP2 expression, which is present in three quarters of human prostate cancers, can activate two critical pathways that have been linked to prostate cancer initiation and progression.

Betulinic acid suppresses constitutive and TNFalpha-induced NF-kappaB activation and induces apoptosis in human prostate carcinoma PC-3 cells

Development of chemoresistance in androgen-refractory prostate cancer cells is partly due to constitutive activation of Rel/NF-kappaB transcription factors that regulate several cell survival and anti-apoptotic genes. In this study we examined whether betulinic acid (BetA), a pentacyclic triterpene from the bark of white birch, is effective in inhibiting NF-kappaB expression in androgen-refractory human prostate cancer cells exhibiting high constitutive NF-kappaB expression. Treatment of PC-3 cells with BetA inhibited DNA binding and reduced nuclear levels of the NF-kappaB/p65. BetA-mediated NF-kappaB inhibition involved decreased IKK activity and phosphorylation of IkappaBalpha at serine 32/36 followed by its degradation. Reporter assays revealed that NF-kappaB inhibition by BetA is transcriptionally active. These effects were found to correlate with a shift in Bax/Bcl-2 ratio and cleavage of poly(ADP)ribose polymerase more towards apoptosis. BetA also inhibited TNFalpha-induced activation of NF-kappaB via the IkappaBalpha pathway, thereby sensitizing the cells to TNFalpha-induced apoptosis. Our studies demonstrate that BetA effectively inhibits constitutive NF-kappaB activation and supports the rationale for targeting NF-kappaB through combination protocols with BetA in androgen-refractory prostate cancer.

Dexamethasone potentiates the antiangiogenic activity of docetaxel in castration-resistant prostate cancer

We sought to characterise whether dexamethasone (DEX) may enhance tumour response to docetaxel in in vitro and in vivo models of metastatic prostate cancer (CaP). In vitro experiments conducted on PC3 and human bone marrow endothelial cells (hBMECs) determined that administration of DEX (10 nM) reduced constitutive nuclear factor-kappaB (NF-kappaB) activity, decreasing interleukin (IL)-8, CXCL1 and VEGF gene expression in PC3 cells. Dexamethasone also attenuated docetaxel-induced NF-kappaB and activator protein-1 transcription and reduced docetaxel-promoted expression/secretion of IL-8 and CXCL1 in PC3 and hBMECs. Although DEX failed to enhance docetaxel cytotoxicity on PC3 cells, DEX potentiated the antiangiogenic activity of docetaxel in vitro, further reducing vessel area and vessel length in developing endothelial tubes (P<0.05). Docetaxel had a potent antiangiogenic activity in the dorsal skin flap-implanted PC3 tumours in vivo. Small blood vessel formation was further suppressed in tumours co-treated with docetaxel and DEX, substantiated by an increased average vessel diameter and segment length and a decreased number of branch points in the residual tumour vasculature (P<0.001). Our data show that DEX potentiates the antiangiogenic activity of docetaxel, suggesting a putative mechanism for the palliative and survival benefits of these agents in metastatic CaP.

NF-kappaB2/p52 enhances androgen-independent growth of human LNCaP cells via protection from apoptotic cell death and cell cycle arrest induced by androgen-deprivation

PURPOSE

Androgen-deprivation therapy only causes a temporary regression of prostate cancer, as all tumors will eventually progress to refractory to hormonal therapy after 1-3 years of treatment. The underlying mechanisms of prostate cancer androgen refractory progression are incompletely understood. In this study, we employed in vitro as well as in vivo models to examine the role of NF-kappaB2/p52 in prostate cancer growth and androgen independent progression.

EXPERIMENTAL DESIGN

The effects of NF-kappaB2/p52 on cell growth, androgen responsiveness, cell cycle and apoptosis were examined in androgen sensitive LNCaP cells. The effect of NF-kappaB2/p52 on tumor growth was examined in intact and castrated male mice.

RESULTS

Overexpression of NF-kappaB2/p52 enhances androgen-sensitive LNCaP human prostate cancer cell growth and clonogenic ability in androgen-deprived condition in vitro. NF-kappaB2/p52 induced androgen-independent growth is through protecting LNCaP cells from apoptotic cell death and cell cycle arrest induced by androgen-deprivation. In addition, NF-kappaB2/p52 stimulates Cyclin D1 expression and knock down of Cyclin D1 expression by siRNA abolished NF-kappaB2/p52-induced cell growth in vitro. Adenoviral mediated NF-kappaB2/p52 expression in LNCaP cells enhances tumor growth in intact male nude mice and induces tumor growth in castrated male nude mice, suggesting that overexpression of NF-kappaB2/p52 induces androgen-independent growth of androgen-sensitive LNCaP cells.

CONCLUSIONS

Overexpression of NF-kappaB2/p52 protects androgen sensitive LNCaP cells from apoptotic cell death and cell cycle arrest induced by androgen-deprivation. NF-kappaB2/p52 activation induces androgen-independent growth in vitro and in vivo.

Delphinidin, a dietary anthocyanidin in pigmented fruits and vegetables: a new weapon to blunt prostate cancer growth

In a recent publication, we have shown that delphinidin, an anthocyanidin induces apoptosis and cell cycle arrest in highly metastatic human prostate cancer (PCa) PC3 cells. Extending these studies, we provide additional evidence that delphinidin induces apoptosis and cell cycle arrest in androgen refractory human PCa 22Rnu1 cells and that these effects are concomitant with inhibition of NFkappaB. We observed that delphinidin treatment to 22Rnu1 cells resulted in a dose-dependent (i) G(2)/M phase cell cycle arrest, (ii) induction of apoptosis (iii) and inhibition of NFkappaB signaling. The induction of apoptosis by delphinidin was mediated via activation of caspases since a general caspase inhibitor Z-VAD-FMK significantly reversed this effect. Delphinidin treatment to cells resulted in a dose-dependent decrease in (i) phosphorylation of IKKgamma (NEMO), (ii) phosphorylation of NFkappaB inhibitory protein IkappaBalpha, (iii) phosphorylation of NFkappaB/p65 at Ser(536) and NFkappaB/p50 at Ser529, (iv) NFkappaB/p65 nuclear translocation, and (v) NFkappaB DNA binding activity. Taken together, our data show that delphinidin induces apoptosis of both androgen independent and androgen refractory human PCa cells via activation of caspases and in addition, this effect might be due to inhibition of NFkappaB signaling. We suggest that delphinidin could be developed as a novel agent against PCa.

A dietary anthocyanidin delphinidin induces apoptosis of human prostate cancer PC3 cells in vitro and in vivo: involvement of nuclear factor-kappaB signaling

Delphinidin, a major anthocyanidin present in many pigmented fruits and vegetables, possesses antioxidant, anti-inflammatory, and antiangiogenic properties. In this study, we provide evidence that it could be developed as a novel agent against human prostate cancer (PCa). We observed that delphinidin treatment to human PCa LNCaP, C4-2, 22Rnu1, and PC3 cells resulted in a dose-dependent inhibition of cell growth without having any substantial effect on normal human prostate epithelial cells. We selected PC3 cells as a test model system because of their highly aggressive proliferative nature. Delphinidin treatment of cells resulted in a dose-dependent induction of apoptosis and arrest of cells in G(2)-M phase. This induction of apoptosis seems to be mediated via activation of caspases because N-benzyloxycarbonyl-Val-Ala-Asp(OMe)-fluromethylketone significantly reduced apoptosis induced by delphinidin. We also observed that delphinidin treatment of cells resulted in a dose-dependent decrease in (a) phosphorylation of IkappaB kinase gamma (NEMO), (b) phosphorylation of nuclear factor-kappaB (NF-kappaB) inhibitory protein IkappaBalpha, (c) phosphorylation of NF-kappaB/p65 at Ser(536) and NF-kappaB/p50 at Ser(529), (d) NF-kappaB/p65 nuclear translocation, and (e) NF-kappaB DNA binding activity. Delphinidin administration (2 mg, i.p. thrice weekly) to athymic nude mice implanted with PC3 cells resulted in a significant inhibition of tumor growth. Analysis of tumors from delphinidin-treated mice showed significant decrease in the expression of NF-kappaB/p65, Bcl2, Ki67, and PCNA. Taken together, our data suggest that delphinidin could be developed as an agent against human PCa.

Pomegranate extract inhibits androgen-independent prostate cancer growth through a nuclear factor-kappaB-dependent mechanism

Constitutive nuclear factor-kappaB (NF-kappaB) activation is observed in androgen-independent prostate cancer and represents a predictor for biochemical recurrence after radical prostatectomy. Dietary agents such as pomegranate extract (PE) have received increasing attention as potential agents to prevent the onset or progression of many malignancies, including prostate cancer. Here, we show that PE inhibited NF-kappaB and cell viability of prostate cancer cell lines in a dose-dependent fashion in vitro. Importantly, maximal PE-induced apoptosis was dependent on PE-mediated NF-kappaB blockade. In the LAPC4 xenograft model, PE delayed the emergence of LAPC4 androgen-independent xenografts in castrated mice through an inhibition of proliferation and induction of apoptosis. Moreover, the observed increase in NF-kappaB activity during the transition from androgen dependence to androgen independence in the LAPC4 xenograft model was abrogated by PE. Our study represents the first description of PE as a promising dietary agent for the prevention of the emergence of androgen independence that is driven in part by heightened NF-kappaB activity.

Chemotherapy-induced CXC-chemokine/CXC-chemokine receptor signaling in metastatic prostate cancer cells confers resistance to oxaliplatin through potentiation of nuclear factor-kappaB transcription and evasion of apoptosis

Constitutive activation of nuclear factor (NF)-kappaB is linked with the intrinsic resistance of androgen-independent prostate cancer (AIPC) to cytotoxic chemotherapy. Interleukin-8 (CXCL8) is a transcriptional target of NF-kappaB whose expression is elevated in AIPC. This study sought to determine the significance of CXCL8 signaling in regulating the response of AIPC cells to oxaliplatin, a drug whose activity is reportedly sensitive to NF-kappaB activity. Administration of oxaliplatin to PC3 and DU145 cells increased NF-kappaB activity, promoting antiapoptotic gene transcription. In addition, oxaliplatin increased the transcription and secretion of CXCL8 and the related CXC-chemokine CXCL1 and increased the transcription and expression of CXC-chemokine receptors, especially CXC-chemokine receptor (CXCR) 2, which transduces the biological effects of CXCL8 and CXCL1. Stimulation of AIPC cells with CXCL8 potentiated NF-kappaB activation in AIPC cells, increasing the transcription and expression of NF-kappaB-regulated antiapoptotic genes of the Bcl-2 and IAP families. Coadministration of a CXCR2-selective antagonist, AZ10397767 (Bioorg Med Chem Lett 18:798-803, 2008), attenuated oxaliplatin-induced NF-kappaB activation, increased oxaliplatin cytotoxicity, and potentiated oxaliplatin-induced apoptosis in AIPC cells. Pharmacological inhibition of NF-kappaBorRNA interference-mediated suppression of Bcl-2 and survivin was also shown to sensitize AIPC cells to oxaliplatin. Our results further support NF-kappaB activity as an important determinant of cancer cell sensitivity to oxaliplatin and identify the induction of autocrine CXCR2 signaling as a novel mode of resistance to this drug.

Androgen receptor targets NFkappaB and TSP1 to suppress prostate tumor growth in vivo

The androgen role in the maintenance of prostate epithelium is subject to conflicting opinions. While androgen ablation drives the regression of normal and cancerous prostate, testosterone may cause both proliferation and apoptosis. Several investigators note decreased proliferation and stronger response to chemotherapy of the prostate cancer cells stably expressing androgen receptor (AR), however no mechanistic explanation was offered. In this paper we demonstrate in vivo anti-tumor effect of the AR on prostate cancer growth and identify its molecular mediators. We analyzed the effect of AR on the tumorigenicity of prostate cancer cells. Unexpectedly, the AR-expressing cells formed tumors in male mice at a much lower rate than the AR-negative controls. Moreover, the AR-expressing tumors showed decreased vascularity and massive apoptosis. AR expression lowered the angiogenic potential of cancer cells, by increasing secretion of an anti-angiogenic protein, thrombospondin-1. AR activation caused a decrease in RelA, a subunit of the pro-survival transcription factor NFkappaB, reduced its nuclear localization and transcriptional activity. This, in turn, diminished the expression of its anti-apoptotic targets, Bcl-2 and IL-6. Increased apoptosis within AR-expressing tumors was likely due to the NFkappaB suppression, since it was restricted to the cells lacking nuclear (active) NFkappaB. Thus we for the first time identified combined decrease of NFkappaB and increased TSP1 as molecular events underlying the AR anti-tumor activity in vivo. Our data indicate that intermittent androgen ablation is preferable to continuous withdrawal, a standard treatment for early-stage prostate cancer. (c) 2007 Wiley-Liss, Inc.

Iron stimulates urokinase plasminogen activator expression and activates NF-kappa B in human prostate cancer cells

Urokinase-type plasminogen activator (uPA) on prostate cancer cell surfaces mediates pericellular proteolysis and destruction of extracellular matrix barriers to tumor invasion and metastasis. Increased expression of tumor-associated uPA leads to enhanced tumor dissemination and poor cancer outcomes in men with prostate cancer. Expression of uPA is regulated in part by the oxidant-sensitive transcription factor, NF-kappa B (NF-kappaB), which is activated by intracellular reactive oxygen intermediates (ROI). This study examined the effect of iron on the production of ROI, activation of NF-kappaB and expression of uPA in the human prostate cancer cell line, PC-3. Treatment of PC-3 cells with iron in the form of ferric nitrilotriacetate (FeNTA) in the absence of added transferrin resulted in a dose-dependent increase in cellular ferritin content in both the presence and absence of neutralizing antibody to the transferrin receptor. Cellular uptake of iron resulted in stimulation of intracellular ROI production, and increases in uPA mRNA, antigen, and activity. Concurrent treatment with the iron chelator, desferrioxamine (DFO) abrogated these effects, and treatment with DFO alone inhibited constitutive uPA production. Finally, we observed nuclear translocation, and therefore activation of NF-kappaB in response to iron exposure. We conclude that iron enters PC-3 cells via a non-transferrin dependent pathway and increases uPA expression. Our data indicate that one mechanism by which iron may stimulate uPA production is through the generation of intracellular ROI and activation of NF-kappaB-mediated signaling pathways.

Obesity, metabolic syndrome, and prostate cancer

Although obesity has been consistently linked to an increased risk of several malignancies, including cancers of the colon, gallbladder, kidney, and pancreas, its role in prostate cancer etiology remains elusive. Data on the association between obesity and prostate cancer incidence are inconsistent, and in some studies obesity is associated with an increase in risk of high-grade prostate cancer but with a decrease in risk of low-grade tumors. In contrast, obesity has been consistently associated with an increased risk of prostate cancer aggressiveness and mortality. The differential effects of obesity on subtypes of prostate cancer suggest etiologic heterogeneity in these tumors and complex interactions between androgen metabolism and several putative risk factors, including insulin resistance, diabetes, inflammation, and genetic susceptibility, on prostate cancer risk. Data on the role of abdominal obesity, insulin resistance, and metabolic syndrome in prostate cancer etiology are limited. Obesity has been shown to be associated with a state of low-grade chronic inflammation, and insulin resistance and the metabolic syndrome are associated with adverse metabolic profiles and with higher circulating concentrations of inflammation-related markers, including leptin, interleukin-6, and tumor necrosis factor-, many of which have been shown to enhance tumor growth. Thus, whether obesity and metabolic syndrome modulate the risk of prostate cancer through chronic inflammation needs to be investigated further. Given that the prevalence of obesity and metabolic syndrome is increasing worldwide and that the world population is aging, the roles of obesity and metabolic syndrome in prostate carcinogenesis warrant further clarification.

Differences in the rate of lymph node invasion in men with clinically localized prostate cancer might be related to the continent of origin

OBJECTIVE

To test whether the rate of lymph node invasion (LNI) differs between patients treated with radical prostatectomy (RP) at a European or a North American centre.

PATIENTS AND METHODS

In all, 1385 men had RP with bilateral lymphadenectomy for clinically localized prostate cancer (587 from Dallas, Texas and 798 from Milan, Italy). Univariate and multivariate analyses focused on the association between the continent of origin and the rate of LNI, after controlling for prostate-specific antigen (PSA) level, clinical stage, biopsy Gleason sum and the number of examined and removed lymph nodes.

RESULTS

European men had higher PSA levels (9.1 vs 7.8 ng/mL), a higher proportion of palpable cancers (44.5 vs 32.8%), more nodes removed (mean 14.9 vs 7.8) and a higher rate of LNI (9.0% vs 1.2%; all differences P < 0.001). In multivariate analyses that controlled for PSA level and clinical variables, European men had an 8.9-fold higher risk of LNI (P < 0.001) than their counterparts from the USA. Among preoperative variables, the continent of origin was the third most informative predictor of LNI (67.5%), after biopsy Gleason sum (74.3%) and the number of examined lymph nodes (71.0%), and improved the ability to predict LNI by 4.7%.

CONCLUSION

Men treated at a European centre had a 7.3-8.9-fold higher rate of LNI, despite adjusting for all clinical and pathological variables. It remains to be shown what predisposes European men to a higher rate of LNI.

High expression of RelA/p65 is associated with activation of nuclear factor-kappaB-dependent signaling in pancreatic cancer and marks a patient population with poor prognosis

Activation of nuclear factor-kappaB (NF-kappaB) signaling was observed in pancreatic adenocarcinoma cell lines and tumours. However, information on the expression of RelA/p65, the major transcription activating NF-kappaB subunit, in these carcinomas and possible correlations thereof with NF-kappaB activation and patient survival is not available. To provide this missing translational link, we analysed expression of RelA/p65 in 82 pancreatic adenocarcinomas by immunohistochemistry. Moreover, we measured activation of the NF-kappaB pathway in 11 tumours by quantitative PCR for NF-kappaB target genes. We observed strong cytoplasmic or nuclear expression of RelA/p65 in 42 and 37 carcinomas, respectively. High cytoplasmic and nuclear expression of RelA/p65 had negative prognostic impact with 2-year survival rates for patients without cytoplasmic or nuclear RelA/p65 positivity of 41 and 40% and rates for patients with strong cytoplasmic or nuclear RelA/p65 expression of 22 and 20%, respectively. High RelA/p65 expression was correlated to increased expression of NF-kappaB target genes. The observation that high expression of RelA/p65 is correlated to an activation of the NF-kappaB pathway and indicates poor patient survival identifies a patient subgroup that might particularly benefit from NF-kappaB-inhibiting agents in the treatment of pancreatic cancer. Based on our findings, this subgroup could be identified by applying simple immunohistochemical techniques.

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

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

Regulation of IkappaB kinase epsilon expression by the androgen receptor and the nuclear factor-kappaB transcription factor in prostate cancer

Although several genes have been associated with prostate cancer progression, it is clear that we are far from understanding all the molecular events implicated in the initiation and progression of the disease to a hormone-refractory state. The androgen receptor is a central player in the initiation and proliferation of prostate cancer and its response to hormone therapy. Nuclear factor-kappaB has important proliferative and antiapoptotic activities that could contribute to the development and progression of cancer cells as well as resistance to therapy. In this study, we report that IkappaB kinase epsilon (IKKepsilon), which is controlled by nuclear factor-kappaB in human chondrocytes, is expressed in human prostate cancer cells. We show that IKKepsilon gene expression is stimulated by tumor necrosis factor-alpha treatment in LNCaP cells and is inhibited by transfection of a dominant-negative form of IkappaBalpha, which prevents the nuclear translocation of p65. Furthermore, we found that tumor necrosis factor-alpha-induced IKKepsilon expression is inhibited by an androgen analogue (R1881) in androgen-sensitive prostate cancer cells and that this inhibition correlates with the modulation of IkappaBalpha expression by R1881. We also noted constitutive IKKepsilon expression in androgen-independent PC-3 and DU145 cells. To our knowledge, this is the first report of an IkappaB kinase family member whose expression is modulated by androgen and deregulated in androgen receptor-negative cells.

Mechanisms of antiprostate cancer by gum mastic: NF-kappaB signal as target

AIM

To study the effect of gum mastic, a natural resin, on the proliferation of androgen-independent prostate cancer PC-3 cells, and further investigate the mechanisms involved in this regulatory system, taking nuclear factor kappaB (NF-kappaB) signal as the target.

METHODS

3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and a flow cytometer were used to detect the effect of gum mastic on the proliferation of PC-3 cells. Then, reporter gene assay, RT-PCR, and Western blotting were carried out to study the effects of gum mastic on the NF-kappaB protein level and the NF-kappaB signal pathway. The expression of genes involved in the NF-kappaB signal pathway, including cyclin D1, inhibitors of kappaBs (I kappaB alpha), and phosphorylated Akt (p-AKT), were measured. In addition, transient transfection assays with the 5X NF-kappaB consensus sequence promoter was also used to test the effects of gum mastic.

RESULTS

Gum mastic inhibited PC-3 cell growth and blocked the PC-3 cell cycle in the G1 phase. Gum mastic also suppressed NF-kappaB activity in the PC-3 cells. The expression of cyclin D1, a crucial cell cycle regulator and an NF-kappaB downstream target gene, was reduced as well. Moreover, gum mastic decreased the p-AKT protein level and increased the I kappa B alpha protein level.

CONCLUSION

Gum mastic inhibited the proliferation and blocked the cell cycle progression in PC-3 cells by suppressing NF-kappaB activity and the NF-kappaB signal pathway.

YC-1 inhibits HIF-1 expression in prostate cancer cells: contribution of Akt/NF-kappaB signaling to HIF-1alpha accumulation during hypoxia

Hypoxia-inducible factor 1 (HIF-1), a transcription factor that is critical for tumor adaptation to microenvironmental stimuli, represents an attractive chemotherapeutic target. YC-1 is a novel antitumor agent that inhibits HIF-1 through previously unexplained mechanisms. In the present study, YC-1 was found to prevent HIF-1alpha and HIF-1beta accumulation in response to hypoxia or mitogen treatment in PC-3 prostate cancer cells. Neither HIF-1alpha protein half-life nor mRNA level was affected by YC-1. However, YC-1 was found to suppress the PI3K/Akt/mTOR/4E-BP pathway, which serves to regulate HIF-1alpha expression at the translational step. We demonstrated that YC-1 also inhibited hypoxia-induced activation of nuclear factor (NF)-kappaB, a downstream target of Akt. Two modulators of the Akt/NF-kappaB pathway, caffeic acid phenethyl ester and evodiamine, were observed to decrease HIF-1alpha expression. Additionally, overexpression of NF-kappaB partly reversed the ability of wortmannin to inhibit HIF-1alpha-dependent transcriptional activity, suggesting that NF-kappaB contributes to Akt-mediated HIF-1alpha accumulation during hypoxia. Overall, we identify a potential molecular mechanism whereby YC-1 serves to reduce HIF-1 expression.

Nuclear localization of nuclear factor-kappaB p65 in primary prostate tumors is highly predictive of pelvic lymph node metastases

PURPOSE

Lymph node invasion (LNI) is associated with increased risk of prostate cancer progression. Unfortunately, pelvic lymph node dissections are fraught with a high rate of false-negative findings, emphasizing the need for highly accurate markers of LNI. Because nuclear factor-kappaB (NF-kappaB) is a candidate marker of prostate cancer progression, we tested the association between nuclear localization of NF-kappaB in radical prostatectomy specimens and the presence of LNI.

EXPERIMENTAL DESIGN

NF-kappaB expression in radical prostatectomy specimens was assessed with a monoclonal NF-kappaB p65 antibody, in 20 patients with LNI and in 31 controls with no LNI and no biochemical relapse 5 years after radical prostatectomy. Univariate and multivariate logistic regression models were used. The accuracy of multivariate predictions with and without NF-kappaB was quantified with the area under the receiver operating characteristics curve and 200 bootstrap resamples were used to reduce overfit bias.

RESULTS

Univariate regression models showed a 7% increase in the odds of observing LNI for each 1% increase in NF-kappaB nuclear staining (odds ratio, 1.07; P = 0.003). In multivariate models, each 1% increase in NF-kappaB was associated with an 8% increase in the odds of LNI (odds ratio, 1.08; P = 0.03) and its statistical significance was only surpassed by the presence of seminal vesicle invasion (P = 0.003). Addition of NF-kappaB to all other predictors increased the accuracy of LNI prediction by 2.3% (from 84.8% to 87.1%; P < 0.001).

CONCLUSION

This is the first study that shows that the extent of nuclear localization of NF-kappaB in primary prostate tumors is highly accurately capable of predicting the probability of locoregional spread of prostate cancer.

Interleukin 6, a Nuclear Factor-κB Target, Predicts Resistance to Docetaxel in Hormone-Independent Prostate Cancer and Nuclear Factor-κB Inhibition by PS-1145 Enhances Docetaxel Antitumor Activity

PURPOSE

To investigate whether nuclear factor kappaB (NF-kappaB)/interleukin 6 (IL-6) was linked to docetaxel response in human prostate cancer cell lines, and whether inhibition of NF-kappaB sensitized tumor cells to docetaxel. We also aimed to correlate IL-6 (as a surrogate marker of NF-kappaB) and docetaxel response in hormone-independent prostate cancer (HIPC) patients.

EXPERIMENTAL DESIGN

Hormone-dependent (LNCaP) and hormone-independent (PC-3 and DU-145) prostate cancer cell lines were exposed to docetaxel alone or combined with the NF-kappaB inhibitor PS-1145 (an inhibitor of IkappaB kinase-2). Effects of dose, exposure time, and schedule dependence were assessed. Activation of NF-kappaB was assayed by electrophoresis mobility shift assay and luciferase reporter assay, IL-6 levels by ELISA, and cell viability by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Cell cycle and apoptosis were assessed by fluorescence-activated cell sorting analysis. Apoptosis was also measured by detection of cleavage of poly(ADP-ribose) polymerase. In patients with metastatic HIPC receiving docetaxel-based chemotherapy, IL-6 serum levels were assayed before chemotherapy and every 3 to 4 weeks thereafter.

RESULTS

PC-3 and DU-145 cells had higher NF-kappaB activity, secreted more IL-6, and were more resistant to docetaxel than LNCaP cells. NF-kappaB activity was induced by docetaxel. Cotreatment with docetaxel and PS-1145 prevented docetaxel-induced NF-kappaB activation, reduced IL-6 production, and increased docetaxel effects on cell viability in PC-3 and DU-145 cells but not in LNCaP. Synergism with docetaxel and PS-1145, as assayed by median-effect principle, was observed in DU-145 and PC-3. In HIPC patients, pretreatment IL-6 serum levels correlated to prostate-specific antigen (PSA) response: median IL-6 level was 10.8+/-9.5 pg/mL in PSA responders versus 36.7+/-20.8 pg/mL (P=0.006) in nonresponders. A PSA response was also linked to a decline in IL-6 levels during treatment. Median overall survival was 6.8 months in patients with high IL-6 versus 16.6 months in those with low IL-6 (P=0.0007). On multivariate analysis, pretreatment IL-6 (P=0.05) was an independent prognostic factor for time to disease progression and survival.

CONCLUSIONS

Inhibition of NF-kappaB emerges as an attractive strategy to enhance docetaxel response in prostate cancer. The interest of this view is further supported by a significant association between high IL-6 in sera of HIPC patients and decreased response to docetaxel.

Molecular markers in the diagnosis of prostate cancer

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

Activation of nuclear factor-kappaB in human prostate carcinogenesis and association to biochemical relapse

Nuclear factor (NF)-κB/p65 regulates the transcription of a wide variety of genes involved in cell survival, invasion and metastasis. We characterised by immunohistochemistry the expression of NF-κB/p65 protein in six histologically normal prostate, 13 high-grade prostatic intraepithelial neoplasia (PIN) and 86 prostate adenocarcinoma specimens. Nuclear localisation of p65 was used as a measure of NF-κB active state. Nuclear localisation of NF-κB was only seen in scattered basal cells in normal prostate glands. Prostatic intraepithelial neoplasias exhibited diffuse and strong cytoplasmic staining but no nuclear staining. In prostate adenocarcinomas, cytoplasmic NF-κB was detected in 57 (66.3%) specimens, and nuclear NF-κB (activated) in 47 (54.7%). Nuclear and cytoplasmic NF-κB staining was not correlated (P=0.19). By univariate analysis, nuclear localisation of NF-κB was associated with biochemical relapse (P=0.0009; log-rank test) while cytoplasmic expression did not. On multivariate analysis, serum preoperative prostate specific antigen (P=0.02), Gleason score (P=0.03) and nuclear NF-κB (P=0.002) were independent predictors of biochemical relapse. These results provide novel evidence for NF-κB/p65 nuclear translocation in the transition from PIN to prostate cancer. Our findings also indicate that nuclear localisation of NF-κB is an independent prognostic factor of biochemical relapse in prostate cancer.