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

Enabling precision medicine by unravelling disease pathophysiology: quantifying signal transduction pathway activity across cell and tissue types

Signal transduction pathways are important in physiology and pathophysiology. Targeted drugs aim at modifying pathogenic pathway activity, e.g., in cancer. Optimal treatment choice requires assays to measure pathway activity in individual patient tissue or cell samples. We developed a method enabling quantitative measurement of functional pathway activity based on Bayesian computational model inference of pathway activity from measurements of mRNA levels of target genes of the pathway-associated transcription factor. Oestrogen receptor, Wnt, and PI3K-FOXO pathway assays have been described previously. Here, we report model development for androgen receptor, Hedgehog, TGFβ, and NFκB pathway assays, biological validation on multiple cell types, and analysis of data from published clinical studies (multiple sclerosis, amyotrophic lateral sclerosis, contact dermatitis, Ewing sarcoma, lymphoma, medulloblastoma, ependymoma, skin and prostate cancer). Multiple pathway analysis of clinical prostate cancer (PCa) studies showed increased AR activity in hyperplasia and primary PCa but variable AR activity in castrate resistant (CR) PCa, loss of TGFβ activity in PCa, increased Wnt activity in TMPRSS2:ERG fusion protein-positive PCa, active PI3K pathway in advanced PCa, and active PI3K and NFκB as potential hormonal resistance pathways. Potential value for future clinical practice includes disease subtyping and prediction and targeted therapy response prediction and monitoring.

Inflammation and NF-κB Signaling in Prostate Cancer: Mechanisms and Clinical Implications

Prostate cancer is a highly prevalent form of cancer that is usually slow-developing and benign. Due to its high prevalence, it is, however, still the second most common cause of death by cancer in men in the West. The higher prevalence of prostate cancer in the West might be due to elevated inflammation from metabolic syndrome or associated comorbidities. NF-κB activation and many other signals associated with inflammation are known to contribute to prostate cancer malignancy. Inflammatory signals have also been associated with the development of castration resistance and resistance against other androgen depletion strategies, which is a major therapeutic challenge. Here, we review the role of inflammation and its link with androgen signaling in prostate cancer. We further describe the role of NF-κB in prostate cancer cell survival and proliferation, major NF-κB signaling pathways in prostate cancer, and the crosstalk between NF-κB and androgen receptor signaling. Several NF-κB-induced risk factors in prostate cancer and their potential for therapeutic targeting in the clinic are described. A better understanding of the inflammatory mechanisms that control the development of prostate cancer and resistance to androgen-deprivation therapy will eventually lead to novel treatment options for patients.

Isoliensinine induces dephosphorylation of NF-kB p65 subunit at Ser536 via a PP2A-dependent mechanism in hepatocellular carcinoma cells: roles of impairing PP2A/I2PP2A interaction

Our previous study discovered that isoliensinine (isolie) triggers hepatocellular carcinoma (HCC) cell apoptosis via inducing p65 dephosphorylation at Ser536 and inhibition of NF-κB. Here, we showed that isolie promoted p65/PP2A interaction in vitro and in vivo. Repression of PP2A activity or knockdown of the expression of PP2A-C (the catalytic subunit of PP2A) abrogated isolie-provoked p65 dephosphorylation. I2PP2A is an endogenous PP2A inhibitor. Isolie directly impaired PP2A/I2PP2A interaction. Knockdown of I2PP2A boosted p65/PP2A association and p65 dephosphorylation. Overexpression of I2PP2A restrained isolie-induced p65 dephosphorylation. Untransformed hepatocytes were insensitive to isolie-induced NF-κB inhibition and cell apoptosis. In these cells, basal levels of I2PP2A and p65 phosphorylation at Ser536 were lower than in HCC cells. These findings collectively indicated that isolie suppresses NF-κB in HCC cells through impairing PP2A/I2PP2A interaction and stimulating PP2A-dependent p65 dephosphorylation at Ser536.

Examination of CK2α and NF-κB p65 expression in human benign prostatic hyperplasia and prostate cancer tissues

Protein kinase CK2 plays a critical role in cell growth, proliferation, and suppression of cell death. CK2 is overexpressed, especially in the nuclear compartment, in the majority of cancers, including prostate cancer (PCa). CK2-mediated activation of transcription factor nuclear factor kappa B (NF-κB) p65 is a key step in cellular proliferation, resulting in translocation of NF-κB p65 from the cytoplasm to the nucleus. As CK2 expression and activity are also elevated in benign prostatic hyperplasia (BPH), we sought to increase the knowledge of CK2 function in benign and malignant prostate by examination of the relationships between nuclear CK2 and nuclear NF-κB p65 protein expression. The expression level and localization of CK2α and NF-κB p65 proteins in PCa and BPH tissue specimens was determined. Nuclear CK2α and NF-κB p65 protein levels are significantly higher in PCa compared with BPH, and these proteins are positively correlated with each other in both diseases. Nuclear NF-κB p65 levels correlated with Ki-67 or with cytoplasmic NF-κB p65 expression in BPH, but not in PCa. The findings provide information that combined analysis of CK2α and NF-κB p65 expression in prostate specimens relates to the disease status. Increased nuclear NF-κB p65 expression levels in PCa specifically related to nuclear CK2α levels, indicating a possible CK2-dependent relationship in malignancy. In contrast, nuclear NF-κB p65 protein levels related to both Ki-67 and cytoplasmic NF-κB p65 levels exclusively in BPH, suggesting a potential separate impact for NF-κB p65 function in proliferation for benign disease as opposed to malignant disease.

Roles of RNA-Binding Proteins in DNA Damage Response

Living cells experience DNA damage as a result of replication errors and oxidative metabolism, exposure to environmental agents (e.g., ultraviolet light, ionizing radiation (IR)), and radiation therapies and chemotherapies for cancer treatments. Accumulation of DNA damage can lead to multiple diseases such as neurodegenerative disorders, cancers, immune deficiencies, infertility, and also aging. Cells have evolved elaborate mechanisms to deal with DNA damage. Networks of DNA damage response (DDR) pathways are coordinated to detect and repair DNA damage, regulate cell cycle and transcription, and determine the cell fate. Upstream factors of DNA damage checkpoints and repair, “sensor” proteins, detect DNA damage and send the signals to downstream factors in order to maintain genomic integrity. Unexpectedly, we have discovered that an RNA-processing factor is involved in DNA repair processes. We have identified a gene that contributes to glioblastoma multiforme (GBM)’s treatment resistance and recurrence. This gene, RBM14, is known to function in transcription and RNA splicing. RBM14 is also required for maintaining the stem-like state of GBM spheres, and it controls the DNA-PK-dependent non-homologous end-joining (NHEJ) pathway by interacting with KU80. RBM14 is a RNA-binding protein (RBP) with low complexity domains, called intrinsically disordered proteins (IDPs), and it also physically interacts with PARP1. Furthermore, RBM14 is recruited to DNA double-strand breaks (DSBs) in a poly(ADP-ribose) (PAR)-dependent manner (unpublished data). DNA-dependent PARP1 (poly-(ADP) ribose polymerase 1) makes key contributions in the DNA damage response (DDR) network. RBM14 therefore plays an important role in a PARP-dependent DSB repair process. Most recently, it was shown that the other RBPs with intrinsically disordered domains are recruited to DNA damage sites in a PAR-dependent manner, and that these RBPs form liquid compartments (also known as “liquid-demixing”). Among the PAR-associated IDPs are FUS/TLS (fused in sarcoma/translocated in sarcoma), EWS (Ewing sarcoma), TARF15 (TATA box-binding protein-associated factor 68 kDa) (also called FET proteins), a number of heterogeneous nuclear ribonucleoproteins (hnRNPs), and RBM14. Importantly, various point mutations within the FET genes have been implicated in pathological protein aggregation in neurodegenerative diseases, specifically with amyotrophic lateral sclerosis (ALS), and frontotemporal lobe degeneration (FTLD). The FET proteins also frequently exhibit gene translocation in human cancers, and emerging evidence shows their physical interactions with DDR proteins and thus implies their involvement in the maintenance of genome stability.

Loss of signal transducer and activator of transcription 1 is associated with prostate cancer recurrence

STAT1 loss has previously been implicated in cell line studies to modify prostate cancer cell growth and survival, however the clinical significance of this has not previously been established. This study investigated if STAT1 loss was associated with patient outcome measures and the phenotypic consequence of STAT1 silencing. STAT1 expression was assessed in two patient cohorts with localised (n = 78) and advanced prostate cancer at initial diagnosis (n = 39) by immunohistochemistry (IHC). Impact of STAT1 silencing on prostate cancer cells lines was assessed using Cell Death detection ELISA, TLDA gene signature apoptosis arrays, WST-1 assay, xCELLigence system, clonogenic assay, and wound healing assay. In the localised patient cohort, low expression of STAT1 was associated with shorter time to disease recurrence (3.8 vs 7.3 years, P = 0.02) and disease specific survival (6.6 vs 9.3 years, P = 0.05). In the advanced patient cohort, low expression was associated with shorter time to disease recurrence (2.0 vs 3.9 years, P = 0.001). When STAT1 was silenced in PC3 cells (AR negative) and LNCaP cells (AR positive) silencing did not influence levels of apoptosis in either cell line and had little effect on cell viability in the LNCaP cells. In contrast, STAT1 silencing in the PC3 cells resulted in a pronounced increase in cell viability (WST-1 assay: mock silenced vs STAT1 silenced, P < 0.001), clonagenicity (clonogenic assay: mock silenced vs STAT1 silenced, P < 0.001), and migration (wound healing: mock silenced vs STAT1 silenced, P < 0.001). In conclusion, loss of STAT1 may promote prostate cancer recurrence in AR negative patients via increasing cell viability. © 2015 Wiley Periodicals, Inc.

Isoliensinine, a Bioactive Alkaloid Derived from Embryos of Nelumbo nucifera, Induces Hepatocellular Carcinoma Cell Apoptosis through Suppression of NF-κB Signaling

Isoliensinine (isolie) is an alkaloid produced by the edible plant Nelumbo nucifera. Here, we unveiled that isolie was able to provoke HepG2, Huh-7, and H22 hepatocellular carcinoma (HCC) cell apoptosis. Isolie decreased NF-κB activity and constitutive phosphorylation of NF-κB p65 subunit at Ser536 in HCC cells. Overexpression of p65 Ser536 phosphorylation mimics abrogated isolie-mediated HCC cell apoptosis. Furthermore, intraperitoneal injection of isolie inhibited the growth of Huh-7 xenografts in nude mice. Additionally, isolie given by both intraperitoneal injection and gavage diminished the proliferation of transplanted H22 cells in Kunming mice. Reduced tumor growth in vivo was associated with inhibited p65 phosphorylation at Ser536 and declined NF-κB activity in tumor tissues. Finally, we revealed that isolie was bioavailable in the blood of mice and exhibited no detectable toxic effects on tumor-bearing mice. Our data provided strong evidence for the anti-HCC effect of isolie.

Prostate-specific G-protein-coupled receptor collaborates with loss of PTEN to promote prostate cancer progression

Among frequent events in prostate cancer are loss of the tumor-suppressor phosphatase and tensin homologue (PTEN) and overexpression of prostate-specific G-protein-coupled receptor (PSGR), but the potential tumorigenic synergy between these lesions is unknown. Here, we report a new mouse model (PSGR-Pten(Δ/Δ)) combining prostate-specific loss of Pten with probasin promoter-driven PSGR overexpression. By 12 months PSGR-Pten(Δ/Δ) mice developed invasive prostate tumors featuring Akt activation and extensive inflammatory cell infiltration. PSGR-Pten(Δ/Δ) tumors exhibited E-cadherin loss and increased stromal androgen receptor (AR) expression. PSGR overexpression increased LNCaP proliferation, whereas PSGR short hairpin RNA knockdown inhibited proliferation and migration. In conclusion, we demonstrate that PSGR overexpression synergizes with loss of PTEN to accelerate prostate cancer development, and present a novel bigenic mouse model that mimics the human condition, where both PSGR overexpression and loss of PTEN occur concordantly in the majority of advanced prostate cancers, yielding an environment more relevant to studying human prostate cancer.

Simultaneous assessment of NF-κB/p65 phosphorylation and nuclear localization using imaging flow cytometry

Aberrant activity of Nuclear Factor-kappaB (NF-κB) is associated with many diseases and is therapeutically targeted. Post-translational modifications, particularly phosphorylation of the RELA/p65 sub-unit, are essential for cytoplasmic to nuclear localization of NF-κB/p65 and initiation of transcription of downstream target genes. Immunoblot and phospho-flow cytometry have been used to study the relationship between phosphorylation motifs and NF-κB activation and microscopic analysis of nuclear localization of p65 is also used as a parameter for activation. The labor intensive nature of these approaches commonly limits the number of sampling points or replicates. Recent insights into the relationship between p65 phosphorylation motifs and their nuclear localization indicate that these parameters have different significances and should not be used interchangeably. In this study, we demonstrate feasibility and reproducibility of studying the relationship between p65 phosphorylation and nuclear translocation using imaging flow cytometry (IFC). TNFα- or PMA/Ionomycin-induced phosphorylation of p65 at serine 529 in cell line models and healthy donor lymphocytes served as the experimental model. IFC analysis demonstrated that expression of phosphorylated serine 529 (P-p65(s529)) increased rapidly following stimulation and that nuclear localization of P-p65(s529) followed the nuclear localization pattern of total p65. However, in the presence of tacrolimus, P-p65(s529) expression was inhibited without affecting nuclear localization of total p65. The data demonstrate the application of IFC to simultaneously assess phosphorylation of p65 and its cellular localization and the results obtained by this analysis corroborate current insights regarding the specific effect of tacrolimus on serine 529 phosphorylation.

Magnetic nanoparticles of Fe3O4 enhance docetaxel-induced prostate cancer cell death

Docetaxel (DTX) is one of the most important anticancer drugs; however, the severity of its adverse effects detracts from its practical use in the clinic. Magnetic nanoparticles of Fe₃O₄ (MgNPs-Fe₃O₄) can enhance the delivery and efficacy of anticancer drugs. We investigated the effects of MgNPs-Fe₃O₄ or DTX alone, and in combination with prostate cancer cell growth in vitro, as well as with the mechanism underlying the cytotoxic effects. MgNPs-Fe₃O₄ caused dose-dependent increases in reactive oxygen species levels in DU145, PC-3, and LNCaP cells; 8-hydroxydeoxyguanosine levels were also elevated. MgNPs-Fe₃O₄ alone reduced the viability of LNCaP and PC-3 cells; however, MgNPs-Fe₃O₄ enhanced the cytotoxic effect of a low dose of DTX in all three cell lines. MgNPs-Fe₃O₄ also augmented the percentage of DU145 cells undergoing apoptosis following treatment with low dose DTX. Expression of nuclear transcription factor κB in DU145 was not affected by MgNPs-Fe₃O₄ or DTX alone; however, combined treatment suppressed nuclear transcription factor κB expression. These findings offer the possibility that MgNPs-Fe₃O₄–low dose DTX combination therapy may be effective in treating prostate cancer with limited adverse effects.

Small-molecule inhibitors of IκB kinase (IKK) and IKK-related kinases

The transcription factors NF-κB and IFN control important signaling cascades and mediate the expression of a number of important pro-inflammatory cytokines, adhesion molecules, growth factors and anti-apoptotic survival proteins. IκB kinase (IKK) and IKK-related kinases (IKKε and TBK1) are key regulators of these biological pathways and, as such, modulators of these enzymes may be useful in the treatment of inflammatory diseases and cancer. We have reviewed the most recent IKK patent literature (2008–2012), added publications of interest overlooked in previous patent reviews and identified all the players involved in small-molecule inhibitors of the IKKs. This will provide the reader with a decisive summary of the IKK arena, a field that has reached maturity over a decade of research.

Estrogen receptor β expression and androgen receptor phosphorylation correlate with a poor clinical outcome in hormone-naive prostate cancer and are elevated in castration-resistant disease

Patients with advanced prostate cancer (PC) are usually treated with androgen withdrawal. While this therapy is initially effective, nearly all PCs become refractory to it. As hormone receptors play a crucial role in this process, we constructed a tissue microarray consisting of PC samples from 107 hormone-naïve (HN) and 101 castration-resistant (CR) PC patients and analyzed the androgen receptor (AR) gene copy number and the protein expression profiles of AR, Serin210-phosphorylated AR (pAR(210)), estrogen receptor (ER)β, ERα and the proliferation marker Ki67. The amplification of the AR gene was virtually restricted to CR PC and was significantly associated with increased AR protein expression (P<0.0001) and higher tumor cell proliferation (P=0.001). Strong AR expression was observed in a subgroup of HN PC patients with an adverse prognosis. In contrast, the absence of AR expression in CR PC was significantly associated with a poor overall survival. While pAR(210) was predominantly found in CR PC patients (P<0.0001), pAR(210) positivity was observed in a subgroup of HN PC patients with a poor survival (P<0.05). Epithelial ERα expression was restricted to CR PC cells (9%). ERβ protein expression was found in 38% of both HN and CR PCs, but was elevated in matched CR PC specimens. Similar to pAR(210), the presence of ERβ in HN patients was significantly associated with an adverse prognosis (P<0.005). Our results strongly suggest a major role for pAR(210) and ERβ in HN PC. The expression of these markers might be directly involved in CR tumor growth.

Inhibitory effect of ARHI on pancreatic cancer cells and NF-κB activity

The aim of this study was to investigate the effect of aplasia ras homolog member I (ARHI) on proliferation, apoptosis and the cell cycle in the pancreatic cancer cell line PANC-1. The study also aimed to examine the effect of ARHI on the activity of the nuclear factor (NF)-κB and to determine whether ARHI acts as a tumor suppressor in the development of pancreatic cancer by inhibiting the activity of NF-κB. A pIRES2‑EGFP‑ARHI vector, constructed by reverse transcrition (RT)‑PCR, was transiently transfected into the PANC-1 cells and analyzed for the expression of the ARHI protein by western blotting. A MTT assay was used to quantify cell proliferation, and apoptosis was analyzed by flow cytometry. The NF‑κB signaling pathway, specifically the pathway using the nuclear phosphorylated p65 isoform, was analyzed by western blotting. Expression of the ARHI protein was detected by western blotting subsequent to the PANC-1 cells being transiently transfected with the pIRES2‑EGFP‑ARHI construct. Cell proliferation was strongly inhibited in the PANC-1 cells transfected with pIRES2‑EGFP‑ARHI. The cell cycle assays indicated an increase in the number of cells at the G0/G1 phase and a decrease in the cells at the S phase, but the difference was not significant (P>0.05). Time course studies also indicated a marked increase in the apoptotic index following transient transfection, as well as a gradual decrease in the expression of the nuclear phosphorylated p65 protein. ARHI acts as a tumor suppressor by downregulating the NF‑κB signaling pathway, which results in the inhibition of cell proliferation, apoptosis and the cell cycle in the pancreatic tumor PANC-1 cell line.

Heart failure induces significant changes in nuclear pore complex of human cardiomyocytes

Aims

The objectives of this study were to analyse the effect of heart failure (HF) on several proteins of nuclear pore complex (NPC) and their relationship with the human ventricular function.

Methods and Results

A total of 88 human heart samples from ischemic (ICM, n = 52) and dilated (DCM, n = 36) patients undergoing heart transplant and control donors (CNT, n = 9) were analyzed by Western blot. Subcellular distribution of nucleoporins was analysed by fluorescence and immunocytochemistry. When we compared protein levels according to etiology, ICM showed significant higher levels of NDC1 (65%, p<0.0001), Nup160 (88%, p<0.0001) and Nup153 (137%, p = 0.004) than those of the CNT levels. Furthermore, DCM group showed significant differences for NDC1 (41%, p<0.0001), Nup160 (65%, p<0.0001), Nup153 (155%, p = 0.006) and Nup93 (88%, p<0.0001) compared with CNT. However, Nup155 and translocated promoter region (TPR) did not show significant differences in their levels in any etiology. Regarding the distribution of these proteins in cell nucleus, only NDC1 showed differences in HF. In addition, in the pathological group we obtained good relationship between the ventricular function parameters (LVEDD and LVESD) and Nup160 (r = −0382, p = 0.004; r = −0.290, p = 0.033; respectively).

Conclusions

This study shows alterations in specific proteins (NDC1, Nup160, Nup153 and Nup93) that compose NPC in ischaemic and dilated human heart. These changes, related to ventricular function, could be accompanied by alterations in the nucleocytoplasmic transport. Therefore, our findings may be the basis for a new approach to HF management.