Immunohistochemical analysis of NF-κB signaling proteins IKKε, p50/p105, p52/p100 and RelA in prostate cancers

AR and YAP crosstalk: impacts on therapeutic strategies in prostate cancer

Prostate cancer ranks as one of the most common types of cancer affecting men worldwide, and its progression is shaped by a diverse array of influencing factors. The AR signaling pathway plays a pivotal role in the pathogenesis of prostate cancer. While existing anti-androgen treatments show initial efficacy, they ultimately do not succeed in halting the advancement to CRPC. Recent studies have identified alterations in the Hippo-YAP signaling pathway within prostate cancer, highlighting intricate crosstalk with the AR signaling pathway. In this review, we examine the interactions and underlying mechanisms between AR and YAP, the key molecules in these two signaling pathways. AR regulates the stability and function of YAP by modulating its transcription, translation, and phosphorylation status, while YAP exerts both promotional and inhibitory regulatory effects on AR. Based on these findings, this paper investigates their significant roles in the onset, progression, and therapeutic resistance of prostate cancer, and discusses the clinical potential of YAP in prostate cancer treatment.

Role of Epigenetic Therapy in the Modulation of Tumor Growth and Migration in Human Castration-Resistant Prostate Cancer Cells with Neuroendocrine Differentiation

INTRODUCTION

Neuroendocrine transdifferentiation (NED) of prostate cancer (PC) cells is associated with the development of resistance to antiandrogen therapy and poor prognosis in patients with castration-resistant PC (CRPC). Many of the molecular events, involved in NED, appear to be mediated by epigenetic mechanisms. In this study, we evaluated the antitumor activity and epigenetic modulation of 2 epigenetic drugs, such as the demethylating agent 5-aza-2'-deoxycytidine (AZA) and the methyl donor S-adenosylmethionine (SAM), in 2 human CRPC cell lines with NED (DU-145 and PC-3).

METHODS

The effects of AZA and SAM on cell viability, cell cycle, apoptosis, migration, and genome-wide DNA methylation profiling have been evaluated.

RESULTS

Both drugs showed a prominent antitumor activity in DU-145 and PC-3 cells, through perturbation of cell cycle progression, induction of apoptosis, and inhibition of cell migration. AZA and SAM reversed NED in DU-145 and PC-3, respectively. Moreover, AZA treatment modified DNA methylation pattern in DU-145 cells, sustaining a pervasive hypomethylation of the genome, with a relevant effect on several pathways involved in the regulation of cell proliferation, apoptosis, and cell migration, in particular Wnt/β-catenin.

CONCLUSIONS

A relevant antitumor activity of these epigenetic drugs on CRPC cell lines with NED opens a new scenario in the therapy of this lethal variant of PC.

Impact of single amino acid substitution on the structure and function of TANK-binding kinase-1

Tank-binding kinase 1 (TBK1) is a serine/threonine protein kinase involved in various signaling pathways and subsequently regulates cell proliferation, apoptosis, autophagy, antiviral and antitumor immunity. Dysfunction of TBK1 can cause many complex diseases, including autoimmunity, neurodegeneration, and cancer. This dysfunction of TBK1 may result from single amino acid substitutions and subsequent structural alterations. This study analyzed the effect of substituting amino acids on TBK1 structure, function, and subsequent disease using advanced computational methods and various tools. In the initial assessment, a total of 467 mutations were found to be deleterious. After that, in detailed structural and sequential analyses, 13 mutations were found to be pathogenic. Finally, based on the functional importance, two variants (K38D and S172A) of the TBK1 kinase domain were selected and studied in detail by utilizing all-atom molecular dynamics (MD) simulation for 200 ns. MD simulation, including correlation matrix and principal component analysis, helps to get deeper insights into the TBK1 structure at the atomic level. We observed a substantial change in variants' conformation, which may be possible for structural alteration and subsequent TBK1 dysfunction. However, substitution S172A shows a significant conformational change in TBK1 structure as compared to K38D. Thus, this study provides a structural basis to understand the effect of mutations on the kinase domain of TBK1 and its function associated with disease progression.

Expression of p52, a non-canonical NF-kappaB transcription factor, is associated with poor ovarian cancer prognosis

BACKGROUND

The canonical and non-canonical nuclear factor-kappaB (NF-κB) signaling pathways have key roles in cancer, but studies have previously evaluated only the association of canonical transcription factors and ovarian cancer survival. Although a number of in vitro and in vivo studies have demonstrated mechanisms by which non-canonical NF-κB signaling potentially contributes to ovarian cancer progression, a prognostic association has yet to be shown in the clinical context.

METHODS

We assayed p65 and p52 (major components of the canonical and non-canonical NF-κB pathways) by immunohistochemistry in epithelial ovarian tumor samples; nuclear and cytoplasmic staining were semi-quantified by H-scores and dichotomized at median values. Associations of p65 and p52 with progression-free survival (PFS) and overall survival (OS) were quantified by Hazard Ratios (HR) from proportional-hazards regression.

RESULTS

Among 196 cases, median p52 and p65 H-scores were higher in high-grade serous cancers. Multivariable regression models indicated that higher p52 was associated with higher hazards of disease progression (cytoplasmic HR: 1.54; nuclear HR: 1.67) and death (cytoplasmic HR: 1.53; nuclear HR: 1.49), while higher nuclear p65 was associated with only a higher hazard of disease progression (HR: 1.40) in unadjusted models. When cytoplasmic and nuclear staining were combined, p52 remained significantly associated with increased hazards of disease progression (HR: 1.91, p = 0.004) and death (HR: 1.70, p = 0.021), even after adjustment for p65 and in analyses among only high-grade serous tumors.

CONCLUSIONS

This is the first study to demonstrate that p52, a major component of non-canonical NF-κB signaling, may be an independent prognostic factor for epithelial ovarian cancer, particularly high-grade serous ovarian cancer. Approaches to inhibit non-canonical NF-κB signaling should be explored as novel ovarian cancer therapies are needed.

IKBKE activity enhances AR levels in advanced prostate cancer via modulation of the Hippo pathway

Resistance to androgen receptor (AR) targeting therapeutics in prostate cancer (PC) is a significant clinical problem. Mechanisms by which this is accomplished include AR amplification and expression of AR splice variants, demonstrating that AR remains a key therapeutic target in advanced disease. For the first time we show that IKBKE drives AR signalling in advanced PC. Significant inhibition of AR regulated gene expression was observed upon siRNA-mediated IKBKE depletion or pharmacological inhibition due to inhibited AR gene expression in multiple cell line models including a LNCaP derivative cell line resistant to the anti-androgen, enzalutamide (LNCaP-EnzR). Phenotypically, this resulted in significant inhibition of proliferation, migration and colony forming ability suggesting that targeting IKBKE could circumvent resistance to AR targeting therapies. Indeed, pharmacological inhibition in the CWR22Rv1 xenograft mouse model reduced tumour size and enhanced survival. Critically, this was validated in patient-derived explants where enzymatic inactivation of IKBKE reduced cell proliferation and AR expression. Mechanistically, we provide evidence that IKBKE regulates AR levels via Hippo pathway inhibition to reduce c-MYC levels at cis-regulatory elements within the AR gene. Thus, IKBKE is a therapeutic target in advanced PC suggesting repurposing of clinically tested IKBKE inhibitors could be beneficial to castrate resistant PC patients.

Advances in IKBKE as a potential target for cancer therapy

IKBKE (inhibitor of nuclear factor kappa-B kinase subunit epsilon), a member of the nonclassical IKK family, plays an important role in the regulation of inflammatory reactions, activation and proliferation of immune cells, and metabolic diseases. Recent studies have demonstrated that IKBKE plays a crucial regulatory role in malignant tumor development. In recent years, IKBKE, an important oncoprotein in several kinds of tumors, has been widely found to regulate a variety of cytokines and signaling pathways. IKBKE promotes the growth, proliferation, invasion, and drug resistance of various cancers. This paper makes a detailed review that focuses on the recent discoveries of IKBKE in the malignant tumors, and puts forward that IKBKE is becoming an important therapeutic target for clinical treatment, which has been more and more realized.

Expression and prognostic role of IKBKE and TBK1 in stage I non-small cell lung cancer

BACKGROUND

The inhibitors of nuclear factor kappa-B kinase subunit epsilon (IKBKE) and TANK-binding kinase 1 (TBK1) are important members of the nonclassical IKK family that share the kinase domain. They are important oncogenes for activation of several signaling pathways in several tumors. This study aims to explore the expression of IKBKE and TBK1 and their prognostic role in stage I non-small cell lung cancer (NSCLC).

PATIENTS AND METHODS

A total of 142 surgically resected stage I NSCLC patients were enrolled and immunohistochemistry of IKBKE and TBK1 was performed.

RESULTS

IKBKE and TBK1 were expressed in 121 (85.2%) and 114 (80.3%) of stage I NSCLC patients respectively. IKBKE expression was significantly associated with TBK1 expression (P=0.004). Furthermore, multivariate regression analyses showed there was a significant relationship between patients with risk factors, the recurrence pattern of metastasis and IKBKE+/TBK1+ co-expression (P=0.032 and P=0.022, respectively).  In Kaplan-Meier survival curve analyses, the IKBKE+/TBK1+ co-expression subgroup was significantly associated with poor overall survival (P=0.014).

CONCLUSIONS

This is the first study to investigate the relationship between IKBKE and TBK1 expression and clinicopathologic characteristics in stage I NSCLC patients. IKBKE+/TBK1+ co-expression was significantly obvious in patients with risk factors and with recurrence pattern of distant metastasis. Furthermore, IKBKE+/TBK1+ is also an effective prognostic predictor for poor overall survival.

Prognostic values of inhibitory κB kinases mRNA expression in human gastric cancer

Background: Inhibitory κB kinases (IKKs) play a key role in modulating proinflammatory and growth stimulating signals through their regulation of the nuclear factor κB (NF-κB) cascade. Therefore, the level of expression of IKKs represents a viable prognostic predictor with regard to various pathological processes. The prognostic value of IKKs expression in gastric cancer remains unclear. Methods: We used the 'Kaplan-Meier plotter' (KM plotter) online database, to explore the predictive prognostic value of individual IKKs members' mRNA expression to overall survival (OS) in different clinical data including pathological staging, histology, and therapies employed. Results: Our results revealed that a higher mRNA expression of inhibitor of NF-κB kinase subunit α (IKKα) was correlated to better OS, whereas higher mRNA expression of IKKβ, inhibitor of NF-κB kinase subunit γ (IKKγ), inhibitor of NF-κB kinase subunit ε (IKKε), and suppressor of IKKε (SIKE) were generally correlated to unfavorable OS in gastric cancer. Increased mRNA expression of IKKε also showed better outcomes in stage IV gastric cancer. Further a correlation between elevated levels of mRNA expression of both IKKε and SIKE was found to have favorable OS in diffuse type gastric cancer. It was also revealed that high expression of SIKE had favorable OS when treated with other adjuvant therapies, while worse OS when treated only with 5FU therapy. Conclusion: Our results suggest that mRNA expression of individual IKKs and SIKE are associated with unique prognostic significance and may act as valuable prognostic biomarkers and potential targets for future therapeutic interventions in gastric cancer.

Angiotensin 1-7 modulates molecular and cellular processes central to the pathogenesis of prostate cancer

Angiotensin 1–7 (Ang1–7) is an endogenous bioactive component of the renin-angiotensin system (RAS). In addition to its cardiovascular properties, its anti-proliferative and anti-angiogenic traits are believed to play important roles in carcinogenesis. The present study examines the influence of Ang1–7 on processes associated with development and progression of prostate cancer cells. Our findings indicate that while Ang1–7 (1 nM; 48 h) can effectively reduce cell proliferation in DU-145, it can induce a significant decrease in the expression of MKI67 in LNCaP. In both cell lines we also observed a reduction in colony size in soft agar assay. A various changes in gene expression were noted after exposure to Ang1–7: those of anti- and pro-apoptotic agents and the NF-kB family of transcription factors, as well as mesenchymal cell markers and vascular endothelial growth factor A (VEGFA). In addition, Ang1–7 was found to modulate cell adhesion and matrix metallopeptidase (MMP) activity. Changes were also observed in the levels of angiotensin receptors and sex steroid hormone receptors. Ang1–7 reduced the levels of estrogen receptor alpha gene (ESR1) and increased the expression of estrogen receptor beta gene (ESR2) in all prostate cancer cells; it also up-regulated androgen receptor (AR) expression in androgen-sensitive cells but contradictory effect was observed in androgen- irresponsive cell lines. In summary, the results confirm the existence of complex network between the various elements of the local RAS and the molecular and cellular mechanisms of prostate cancerogenesis. The response of cancer cells to Ang1–7 appears to vary dependently on the dose and time of incubation as well as the aggressiveness and the hormonal status of cells.

p52 expression enhances lung cancer progression

While many studies have demonstrated that canonical NF-κB signaling is a central pathway in lung tumorigenesis, the role of non-canonical NF-κB signaling in lung cancer remains undefined. We observed frequent nuclear accumulation of the non-canonical NF-κB component p100/p52 in human lung adenocarcinoma. To investigate the impact of non-canonical NF-κB signaling on lung carcinogenesis, we employed transgenic mice with doxycycline-inducible expression of p52 in airway epithelial cells. p52 over-expression led to increased tumor number and progression after injection of the carcinogen urethane. Gene expression analysis of lungs from transgenic mice combined with in vitro studies suggested that p52 promotes proliferation of lung epithelial cells through regulation of cell cycle-associated genes. Using gene expression and patient information from The Cancer Genome Atlas (TCGA) database, we found that expression of p52-associated genes was increased in lung adenocarcinomas and correlated with reduced survival, even in early stage disease. Analysis of p52-associated gene expression in additional human lung adenocarcinoma datasets corroborated these findings. Together, these studies implicate the non-canonical NF-κB component p52 in lung carcinogenesis and suggest modulation of p52 activity and/or downstream mediators as new therapeutic targets.

Expression of AIMP1, 2 and 3, the scaffolds for the multi-tRNA synthetase complex, is downregulated in gastric and colorectal cancer

Aminoacyl-tRNA synthetase-interacting multifunctional proteins (AIMPs) form a protein complex with aminoacyl-tRNA synthetases. In addition to protein translation, AIMPs play a role in diverse biological processes. Earlier studies suggested that AIMPs may act as tumor suppressors. However, the expression status of the AIMP proteins in human cancer tissues is largely unknown. In this study, we analyzed the expression of AIMP members (AIMP1, AIMP2 and AIMP3) in gastric cancer (GC) and colorectal cancer (CRC) tissues. We analyzed the expression of these proteins in 100 GC and 103 CRC tissues by immunohistochemistry using a tissue microarray method. Normal gastric and colon mucosa expressed AIMP1, AIMP2 and AIMP3 in nearly all of the cases (95–100%). However, the expression of AIMP1, AIMP2 and AIMP3 was significantly decreased in the GC samples (60%, 52% and 70% of the cases, respectively) and in the CRC samples (66%, 53% and 81% of the cases, respectively) (P <0.01). Expression of AIMP1, AIMP2 or AIMP3 was not associated with clinicopathological parameters including differentiation, depth of invasion and TNM stage. The decreased expression of AIMP1, AIMP2 and AIMP3 in the GC and CRC tissues compared to the corresponding normal tissues suggested that downregulation of these proteins may be related to inactivation of the tumor suppressor functions of AIMP proteins and might play a role in the development of GC and CRC.

MiR-98 Promotes Apoptosis of Glioma Cells via Suppressing IKBKE/NF-κB Pathway

The inhibitor of kappa B kinase epsilon is overexpressed in glioma and plays antiapoptotic role via activating nuclear factor-kappa B. microRNA-98 can suppress glioma, modulate the activities of nuclear factor-kappa B, and bind to the 3′-untranslated region of inhibitor of kappa B kinase epsilon messenger RNA. This study was aimed to investigate the modulation of inhibitor of kappa B kinase epsilon/nuclear factor-kappa B by microRNA-98 in glioma. The results indicated that microRNA-98 was downregulated in glioma cell lines and human glioma tissues. Overexpression of microRNA-98 in U87MG and T98G glioma cells significantly increased the apoptosis induced by ultraviolet irradiation and suppressed nuclear factor-kappa B luciferase activity, nuclear factor-kappa B p50 subunit expression, and B-cell lymphoma-2 (Bcl-2) expression in glioma cells. Silencing inhibitor of kappa B kinase epsilon decreased the expression of nuclear factor-kappa B p50 subunit and the luciferase activity of nuclear factor-kappa B, while the nuclear factor-kappa B activity could be significantly retrieved when inhibitor of kappa B kinase epsilon was expressed in microRNA-98-transfected cells. These findings indicated that microRNA-98 could promote apoptosis of glioma cells via inhibiting inhibitor of kappa B kinase epsilon/nuclear factor-kappa B signaling and presented a novel regulatory pathway of microRNA-98 by direct suppression of inhibitor of kappa B kinase epsilon/nuclear factor-kappa B expression in glioma cells.

Prognostic value of GRIM-19, NF-κB and IKK2 in patients with high-grade serous ovarian cancer

AIMS

High grade serous carcinoma (HGSC) is an aggressive tumour, and most patients relapse after treatment, acquiring resistance to platinum-based chemotherapy. One of the resistance mechanisms proposed is apoptosis evasion triggered by drug-related cytotoxic effect in the cell. In this context, this study aims to evaluate the protein expression of GRIM-19, NF-κB and IKK2, their association with chemotherapy response and to determine their prognostic values in HGSC.

METHODS

GRIM-19, NF-κB and IKK2 expression was evaluated by immunohistochemistry (IHC) in 71 patients with HGSC selected between 2003 and 2013, whose underwent primary debulking surgery with complete cytoreduction. Protein expression was analyzed in relation to platinum response groups, tumour progression, clinicopathological data and survival.

RESULTS

Positive IKK2 expression was related to resistance (p = 0.011), shorter disease-free survival (p = 0.001) and overall survival (p = 0.026) and was also a risk factor for relapse (p = 0.002) and death (p = 0.032). The association between IKK2 and NF-κB positivity predicted a subgroup with shorter overall survival (p = 0.004), disease-free survival (p = 0.003) and resistance to platinum-based chemotherapy (p = 0.036). NF-κB positivity was associated with worse overall survival (p = 0.005) and disease-free survival (p = 0.027) and was a positive predictor for relapse (p = 0.032) and death (p = 0.008). Higher expression of GRIM-19 was associated with higher disease-free survival (p = 0.039) and was a negative predictor for relapse (p = 0.046).

CONCLUSIONS

GRIM-19 is a potential predictor of prognosis and disease recurrence in HGSC. IKK2 and NF-κB are related to poor prognosis and are potential predictors of response to platinum-based chemotherapy in HGSC. IHC analyses of GRIM19, IKK2 and NF-κB may be important in the attempt to provide prognostic values for relapse and response to treatment in patients with HGSC.

IKKε and TBK1 expression in gastric cancer

Inhibitor of kappa B kinase epsilon (IKKε) and TANK-binding kinase 1 (TBK1) are non-canonical IKKs. IKKε and TBK1 share the kinase domain and are similar in their ability to activate the nuclear factor-kappa B signaling pathway. IKKε and TBK1 are overexpressed through multiple mechanisms in various human cancers. However, the expression of IKKε and TBK1 in gastric cancer and their role in prognosis have not been studied.

To investigate overexpression of the IKKε and TBK1 proteins in gastric cancer and their relationship with clinicopathologic factors, we performed immunohistochemical staining using a tissue microarray. Tissue microarray samples were obtained from 1,107 gastric cancer patients who underwent R0 gastrectomy with extensive lymph node dissection and adjuvant chemotherapy.

We identified expression of IKKε in 150 (13.6%) and TBK1 in 38 (3.4%) gastric cancers. Furthermore, co-expression of IKKε and TBK1 was identified in 1.5% of cases. Co-expression of IKKε and TBK1 was associated with differentiated intestinal histology and earlier T stage. In a multivariate binary logistic regression model, intestinal histologic type by Lauren classification and early AJCC stage were significant predictors for expression of IKKε and TBK1 proteins in gastric cancer. Changes in IKKε and TBK1 expression may be involved in the development of intestinal-type gastric cancer. The overexpression of IKKε and TBK1 should be considered in selected patients with intestinal-type gastric cancer.

In conclusion, this is the first large-scale study investigating the relationships between expression of IKKε and TBK1 and clinicopathologic features of gastric cancer. The role of IKKε and TBK1 in intestinal-type gastric cancer pathogenesis should be elucidated by further investigation.

Regulation of mRNA gene expression of members of the NF-κB transcription factor gene family by angiotensin II and relaxin 2 in normal and cancer prostate cell lines

An increasing number of researchers are focusing on the influence of local peptide hormones such as angiotensin II (Ang II) and relaxin 2 (RLN2) in the regulation of inflammation and carcinogenesis. The interaction between the renin‑angiotensin system (RAS) and relaxin family peptide system (RFPS) is known to influence the proliferation, adhesion and migration of normal and cancer prostate cell lines. The aim of the present study was to evaluate changes in the expression of nuclear factor‑κB subunit 1 (NFKB1), nuclear factor‑κB subunit 2 (NFKB2), REL proto‑oncogene nuclear factor‑κB p65 subunit (REL), RELA proto‑oncogene nuclear factor‑κB subunit (RELA) and RELB proto‑oncogene nuclear factor‑κB subunit (RELB) mRNA caused by Ang II and RLN2. The members of NF‑kB family are involved in many processes associated with cancer development and metastasis. Reverse transcription‑quantitative polymerase chain reaction analysis identified that both peptide hormones have an influence on the relative expression of nuclear factor‑κB. Following treatment with either peptide, NFKB1 expression was downregulated in all prostate cancer cell lines (LNCaP, DU‑145 and PC3), but not in normal epithelial cells (PNT1A). Conversely, RELB mRNA was enhanced only in non‑cancerous prostate cells. RELA expression was strongly stimulated in the most aggressive cell line, whereas REL mRNA was unchanged. In many cases, the effect was strictly dependent on the cell line and/or the type of peptide: Ang II increased expression of both RELA and REL genes in the androgen‑dependent cell line while RLN2 enhanced NFKB2 and RELA mRNA in androgen‑independent cells (DU‑145). Further research is needed to understand the regulation of NF‑κB family members by key renin‑angiotensin system and RFPS peptides in prostate cancer cells; however, prostate carcinogenesis appears to be influenced by the balance between the cross‑regulation of nuclear factor‑κB (NF‑κB) and androgen receptor pathways by Ang II and relaxin 2.

The protein kinase IKKepsilon contributes to tumour growth and tumour pain in a melanoma model

Inhibitor-kappaB kinase epsilon (IKKε) constitutes a non-canonical I-κB kinase, which amongst others modulates NF-κB activity. IKKε and NF-κB have both been described for their role in cell proliferation and their dysregulation has been associated with tumourigenesis and metastasis in multiple cancer types. Accordingly, overexpression and constitutive activation of NF-κB have also been shown in melanoma, however, the role of IKKε in this cancer type has not been investigated so far. Thus, we determined IKKε expression in malignant melanoma cells and we were able to show a significant overexpression of IKKε in tumour cells in comparison to melanocytes. Inhibition of IKKε either by shRNA or the pharmacological inhibitor amlexanox resulted in reduced cell proliferation associated with a cell cycle block in the G1-phase. Functional analysis indicated that NF-κB, Akt1 and MAPK pathways might be involved in the IKKε-mediated effects. In vivo, we applied a mouse melanoma skin cancer model to assess tumour growth and melanoma-associated pain in IKKε knockout mice as well as C57BL/6 mice after inoculation with IKKε-negative cells. In IKKε knockout mice, tumour growth was not altered as compared to IKKε wild type mice. However, melanoma associated pain was strongly suppressed accompanied by a reduced mRNA expression of a number of pain-relevant genes. In contrast, after inoculation of IKKε-depleted tumour cells, the development of melanoma was almost completely prevented. In conclusion, our data suggest that IKKε in the tumour plays an essential role in tumour initiation and progression while IKKε expression in tumour surrounding tissues contributes to melanoma-associated pain.

Polymorphisms of IKBKE gene are associated with major depressive disorder and panic disorder

BACKGROUND

The immune system has been increasingly implicated in the development of mood and anxiety disorders. Inhibitor of kappa light polypeptide gene enhancer in B cells, kinase epsilon (IKBKE) gene encodes IKKε protein that is involved in innate immunity, predominantly antiviral response generation. It also bears pro-inflammatory properties that could affect psychiatric outcomes. In order to investigate the possible role of IKBKE gene in major depressive disorder (MDD) and panic disorder (PD), we conducted a case-control genetic association study concerning these disorders.

METHODS

In all, 14 SNPs of IKBKE gene were genotyped in groups of 391 patients with MDD and 190 patients with PD together with respective 389 and 371 healthy control individuals. The given groups were further divided by gender for additional analyses.

RESULTS

Substantial genetic associations were revealed between IKBKE SNPs and MDD (multiple testing adjusted P < 0.05) and suggestive associations in case of PD (P(adj) > 0.05). In addition, two SNPs that were only associated with PD among males, also displayed significantly different allele frequencies compared to PD females. This may indicate a specific role of these SNPs in male PD, but caution should be applied here due to the small size of the studied PD males group.

CONCLUSIONS

The results of this study confirm our initial findings and indicate a possible role of IKBKE gene in mood and anxiety disorders.

The potential evasion of immune surveillance in mucosa associated lymphoid tissue lymphoma by DcR2-mediated up-regulation of nuclear factor-κB

This study investigated expression profiles of tumor necrosis factor (TNF)-related apoptosis inducing ligand (TRAIL) pathway components and mechanisms underlying TRAIL-induced apoptosis in mucosa associated lymphoid tissue (MALT) lymphoma. Genetic aberrations including translocations and trisomies were assessed by reverse transcription polymerase chain reaction and fluorescence in situ hybridization. Expression of TRAIL, death receptors 4 and 5, decoy receptors 1 and 2, and FADD-like interleukin-1β-converting enzyme (FLICE) inhibitory protein was analyzed by immunohistochemistry. All 32 patients under study showed some alterations in TRAIL pathway mainly involving loss of death receptors (37.5%), gain of decoy receptors (3.1%) or both (59.4%). Decoy receptor 2 (DcR2) was highly expressed in patients with normal cytogenetic status as compared to those with cytogenetic aberrations (p = 0.005). Moreover, DcR2 expression correlated significantly with nuclear factor-κB (NF-κB) expression (R = 0.372, p = 0.047). High expression of DcR2 in patients with normal cytogenetic status and its significant correlation with NF-κB expression provides a potential clue to evasion of immune surveillance in cytogenetically normal MALT lymphomas.

Blockage of RelB expression by gene silencing enhances the radiosensitivity of androgen‑independent prostate cancer cells

Levels of the nuclear factor‑kappa B (NF‑κB) alternative pathway member RelB have been shown to correlate with the effect of radiation therapy in prostate cancer. RelB expression was evaluated by immunohistochemistry in normal prostate, benign prostate hyperplasia and prostate cancer specimens. RM‑1 cells were pretreated with RelB siRNA prior to radiation therapy, and RelB expression in cytoplasmic and nuclear extracts was detected by real‑time polymerase chain reaction and western blot analysis. The apoptotic rates of experimental RM‑1 cell groups were assessed by flow cytometry. A clonogenic growth array was used to evaluate the radiosensitivity of RM‑1 cell groups. The NF‑κB family member RelB was expressed at a high level in prostate cancer specimens. Compared with irradiated control cells, RM‑1 cells transfected with RelB siRNA and treated with radiation therapy demonstrated a significant downregulation of RelB expression in the cytoplasm and nucleus. Notably, flow cytometry revealed that pretreatment of RM‑1 cells with RelB siRNA enhanced the apoptotic rate in response to radiation therapy compared with controls. Clonogenic growth assay results revealed enhanced radiosensitivity of RelB siRNA cells at various dosage points compared with control groups. Blockage of the alternative NF‑κB pathway via RelB silencing is a promising approach to enhance the radiosensitivity of prostate cancer.

A monoterpene, unique component of thyme honeys, induces apoptosis in prostate cancer cells via inhibition of NF-κB activity and IL-6 secretion

We have previously demonstrated that Greek thyme honey inhibits significantly the cell viability of human prostate cancer cells. Herein, 15 thyme honey samples from several regions of Greece were submitted to phytochemical analysis for the isolation, identification and determination (through modern spectral means) of the unique thyme honey monoterpene, the compound trihydroxy ketone E-4-(1,2,4-trihydroxy-2,6,6-trimethylcyclohexyl)-but-3-en-2-one. We investigated the anti-growth and apoptotic effects of the trihydroxy ketone on PC-3 human androgen independent prostate cancer cells using MTT assay and Annexin V-FITC respectively. The molecular pathways involved to such effects were further examined by evaluating its ability to inhibit (a) the NF-κB phosphorylation (S536), (b) JNK and Akt phosphorylation (Thr183/Tyr185 and S473 respectively) and (c) IL-6 production, using ELISA method. The anti-microbial effects of the trihydroxy ketone against a panel of nine pathogenic bacteria and three fungi were also assessed. The trihydroxy ketone exerted significant apoptotic activity in PC-3 prostate cancer cells at 100 μM, while it inhibited NF-κB phosphorylation and IL-6 secretion at a concentration range 10(-6)-10(-4)M. Akt and JNK signaling were not found to participate in this process. The trihydroxy ketone exerted significant anti-microbial profile against many human pathogenic bacteria and fungi (MIC values ranged from 0.04 to 0.57 mg/ml). Conclusively, the Greek thyme honey-derived monoterpene exerted significant apoptotic activity in PC-3 cells, mediated, at least in part, through reduction of NF-κB activity and IL-6 secretion and may play a key role in the anti-growth effect of thyme honey on prostate cancer cells.

Proteomics and NF-κB: an update

The transcription factor NF-κB was discovered in 1986 and since then has been extensively studied in relation to cancer research and inflammatory or autoimmune diseases due to its important roles in the regulation of apoptosis and inflammation as well as innate and adaptive immunity. Although much is known about NF-κB signaling, novel NF-κB functions in different diseases are still being uncovered, together with its target proteins, interaction partners and regulators of its activation cascade. Proteomic approaches are particularly suited to the discovery of new proteins involved in distinct signal transduction cascades. This review provides an update on and extension of a recent review that summarized a number of proteomic approaches to NF-κB signaling. The studies discussed here utilized innovative techniques and offer several new hypotheses on the role of NF-κB in physiological and pathophysiological processes, which open new avenues for research on NF-κB in the future.

Diabetes protects from prostate cancer by downregulating androgen receptor: new insights from LNCaP cells and PAC120 mouse model

Type 2 diabetes has been associated with decreased risk of prostate cancer in observational studies, and this inverse association has been recently confirmed in several large cohort studies. However the mechanisms involved in this protective effect remain to be elucidated. The aim of the present study was to explore whether different features of type 2 diabetes (hyperinsulinemia, hyperglycemia and tumor necrosis factor alpha [TNF-α]) protect against the development of prostate cancer. For this purpose LNCaP cells were used for in vitro experiments and nude mice in which PAC120 (hormone-dependent human prostate cancer) xenografts had been implanted were used for in vivo examinations. We provide evidence that increasing glucose concentrations downregulate androgen receptor (AR) mRNA and protein levels through NF-κB activation in LNCaP cells. Moreover, there was a synergic effect of glucose and TNFα in downregulating the AR in LNCaP cells. By contrast, insulin had no effect on AR regulation. In vivo experiments showed that streptozotocin-induced diabetes (STZ-DM) produces tumor growth retardation and a significant reduction in AR expression in PAC120 prostate cancer mice. In conclusion, our results suggest that hyperglycemia and TNF-α play an important role in protecting against prostate cancer by reducing androgen receptor levels via NF-κB.

Celastrol suppresses tumor cell growth through targeting an AR-ERG-NF-κB pathway in TMPRSS2/ERG fusion gene expressing prostate cancer

The TMPRSS2/ERG (T/E) fusion gene is present in the majority of all prostate cancers (PCa). We have shown previously that NF-kB signaling is highly activated in these T/E fusion expressing cells via phosphorylation of NF-kB p65 Ser536 (p536). We therefore hypothesize that targeting NF-kB signaling may be an efficacious approach for the subgroup of PCas that carry T/E fusions. Celastrol is a well known NF-kB inhibitor, and thus may inhibit T/E fusion expressing PCa cell growth. We therefore evaluated Celastrol's effects in vitro and in vivo in VCaP cells, which express the T/E fusion gene. VCaP cells were treated with different concentrations of Celastrol and growth inhibition and target expression were evaluated. To test its ability to inhibit growth in vivo, 0.5 mg/kg Celastrol was used to treat mice bearing subcutaneous VCaP xenograft tumors. Our results show Celastrol can significantly inhibit the growth of T/E fusion expressing PCa cells both in vitro and in vivo through targeting three critical signaling pathways: AR, ERG and NF-kB in these cells. When mice received 0.5 mg/kg Celastrol for 4 times/week, significant growth inhibition was seen with no obvious toxicity or significant weight loss. Therefore, Celastrol is a promising candidate drug for T/E fusion expressing PCa. Our findings provide a novel strategy for the targeted therapy which may benefit the more than half of PCa patients who have T/E fusion expressing PCas.

IκB kinase ε (IKKε): a therapeutic target in inflammation and cancer

The innate immune system forms our first line of defense against invading pathogens and relies for a major part on the activation of two transcription factors, NF-κB and IRF3. Signaling pathways that activate these transcription factors are intertwined at the level of the canonical IκB kinases (IKKα, IKKβ) and non-canonical IKK-related kinases (IKKε, TBK1). Recently, significant progress has been made in understanding the function and mechanism of action of IKKε in immune signaling. In addition, IKKε impacts on cell proliferation and transformation, and is thereby also classified as an oncogene. Studies with IKKε knockout mice have illustrated a key role for IKKε in inflammatory and metabolic diseases. In this review we will highlight the mechanisms by which IKKε impacts on signaling pathways involved in disease development and discuss its potential as a novel therapeutic target.

Prognostic value of nuclear factor κ B expression in patients with advanced cervical cancer undergoing radiation therapy followed by hysterectomy

Aims

The nuclear factor κ B (NF-κB) family comprises transcription factors that promote the development and progression of cancer. The NF-κB pathway is induced by radiation therapy and may be related to tumour radioresistance. The aim of this study was to evaluate the expression of NF-κB as a predictor of the response to radiotherapy and its value as a prognostic marker.

Methods

A retrospective analysis was performed in a series of 32 individuals with stage IB2 and IIB cervical cancer who underwent radiotherapy, followed by radical hysterectomy, from January 1992 to June 2001. NF-κB-p65 and NF-κB-p50 expression was examined by immunohistochemistry in biopsies from all patients before radiotherapy and in 12 patients with residual tumours after radiotherapy.

Results

16 (50%) patients had residual disease after radical hysterectomy. The median follow-up time was 73.5 months, and the 5-year overall survival was 66.5%. Before radiotherapy, cytoplasmic expression of NF-κB-p65 and NF-κB-p50 was noted in 91% and 97% of cases, respectively, versus 59% of cases with nuclear expression of these subunits. Cytoplasmic expression of NF-κB-p65 and NF-κB-p50 in the residual tumours after radiotherapy was observed in 50% of cases; 75% of cases with residual tumours had nuclear expression of NF-κB-p50 versus none with NF-κB-p65. NF-κB-p65 and NF-κB-p50 did not correlate with the risk of residual tumours after radiotherapy or recurrence or death.

Conclusions

These data suggest that NF-κB does not predict the response to radiotherapy and does not correlate with poor outcomes in advanced cervical cancer.

Nuclear factor κB predicts poor outcome in patients with hormone-naive prostate cancer with high nuclear androgen receptor

Despite recent advances in prostate cancer treatments, disease recurrence is common and associated with significant morbidity and mortality. The need for more effective antitumor agents has led researchers to target signaling pathways that drive tumorigenesis by modulating or bypassing androgen receptor signaling--attenuation or blockade of which current treatments aim to effect. The transcription factor nuclear factor κB/p65 has been implicated in prostate cancer progression; however, few studies have examined the involvement of nuclear factor κB in hormone-naive disease. We used immunohistochemistry to investigate expression of p65, androgen receptor, Ki-67, and phosphorylation status of p65 at serine 536, in 154 tumor samples taken from patients before hormone ablation or radical treatment. Nuclear p65 expression was significantly associated with disease-specific mortality: P = .005; hazard ratio, 2.2. When patients were stratified according to androgen receptor status, this relationship was abolished in low androgen receptor-expressing patients and potentiated in high androgen receptor-expressing patients: P = .002; hazard ratio, 3.1. Ki-67 expression was also prognostic of shorter disease-specific mortality: P = .001; hazard ratio, 2.3. When the cohort was stratified according to androgen receptor status, this relationship held for high androgen receptor expressers but not low expressers: P = .0003; hazard ratio, 3.5. Neither androgen receptor nor p65 phosphorylated at S536 were significantly prognostic when considered individually. These data suggest that future prostate cancer treatments that target nuclear factor κB signaling should be assigned primarily to patients with concomitant high nuclear p65 and androgen receptor expression.

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.

IKBKE is over-expressed in glioma and contributes to resistance of glioma cells to apoptosis via activating NF-κB

IκB kinase-ε (IKBKE), a member of the IκB kinase (IKK) family, has been identified as an oncogenic protein and found to be up-regulated in breast cancer, ovarian cancer and prostate cancer. Nonetheless, the expression status and functional significance of IKBKE in human glioma remain unexplored. For the first time, we have demonstrated that mRNA and protein levels of IKBKE were robustly up-regulated in glioma cell lines and human primary glioma tissues. Immunohistochemistry analysis revealed that 53.5% (38/71) paraffin-embedded archived glioma specimens exhibited high levels of IKBKE expression. Intriguingly, there was no significant difference in IKBKE expression among different grades of glioma. To understand the biological function of IKBKE in the development and progression of human glioma, glioma cells lines ectopically over-expressing IKBKE were established and tested for their responsiveness to apoptotic inducers. Our data showed that IKBKE over-expression inhibited cell apoptosis induced by UV irradiation or adriamycin and, in contrast, shRNAi-mediated suppression of IKBKE increased the sensitivity of glioma cells to the apoptotic inducers. Importantly, we found that up-regulated IKBKE could induce the expression of Bcl-2 through activating NF-κB signalling, and that, specifically, we identified IκB as a critical component for this signalling cascade. The current study suggests that up-regulation of IKBKE may represent an important molecular hallmark that is biologically and clinically relevant to the development and progression, as well as the chemo- and radio-resistance, of the disease.

Analysis of NF-kappaB signaling pathways by proteomic approaches

NF-kappaB is a transcription factor that plays important roles in the regulation of apoptosis and inflammation as well as innate and adaptive immunity. Consequently, dysregulations in the NF-kappaB activation cascade have been associated with the pathogenesis of several diseases such as cancer, atherosclerosis and rheumatoid arthritis. Although NF-kappaB signaling pathways have been extensively investigated in this context, its varying components and targets are far from being completely elucidated. There is still an urgent need for the detection of novel NF-kappaB target proteins, novel interaction partners and novel regulators in the activation cascade, in particular with regard to its role in the aforementioned diseases. Therefore, several groups have performed different proteomic approaches to further investigate NF-kappaB signal transduction pathways. Most of these studies have been carried out in the area of cancer research; however, there are also several analyses in the field of inflammatory or autoimmune diseases. Furthermore, there have been a number of basic investigations that principally examined binding partners or so far unknown target proteins of NF-kappaB-related proteins. With these approaches, a number of novel and interesting proteins have been found that interfere with NF-kappaB signal transduction and might have an impact on NF-kappaB-related diseases. The results of these studies are summarized and discussed in this review.