A-kinase-interacting protein 1 (AKIP1) acts as a molecular determinant of PKA in NF-kappaB signaling

Immune Response and Transcriptome Analysis of the Head Kidney to Different Concentrations of Aeromonas veronii in Common Carp (Cyprinus carpio)

The common carp (Cyprinus carpio), a major economic freshwater fish, is suffering from a variety of bacterial infectious diseases because of its high-density, factory and intensive farming patterns. Aeromonas veronii is the causative agent of high mortality in common carp, causing severe economic losses in aquaculture. However, the regulatory mechanisms involved in the response of common carp to this bacterial infection remain poorly understood. In this study, we compared mortality, blood serum LZM (Lysozyme) and IgM (Immunoglobulin M) levels and transcriptome patterns of head kidney tissues after infection with different concentrations of Aeromonas veronii. We observed that mortality increased progressively with an increasing pathogen concentration. The concentrations of blood serum LZM and IgM significantly increased after infection. A total of 13 and 925 differentially expressed genes (DEGs) were identified after infection with low (T4) and high (T9) concentrations of bacterial suspension, respectively. KEGG and GO analyses of the DEGs highlighted multiple immune-related signaling pathways. Weighted gene co-expression network analysis (WGCNA) revealed that 136 and 83 hub genes were related to blood serum LZM and IgM, respectively. Finally, the gene expression in the head kidney was validated via RT-qPCR to be consistent with the transcriptome. These results provide insights into the mechanisms of the immune response to infection with different concentrations of Aeromonas veronii and offer useful information for further studies on immune defense mechanisms in common carp.

Beyond PDE4 inhibition: A comprehensive review on downstream cAMP signaling in the central nervous system

Cyclic adenosine monophosphate (cAMP) is a key second messenger that regulates signal transduction pathways pivotal for numerous biological functions. Intracellular cAMP levels are spatiotemporally regulated by their hydrolyzing enzymes called phosphodiesterases (PDEs). It has been shown that increased cAMP levels in the central nervous system (CNS) promote neuroplasticity, neurotransmission, neuronal survival, and myelination while suppressing neuroinflammation. Thus, elevating cAMP levels through PDE inhibition provides a therapeutic approach for multiple CNS disorders, including multiple sclerosis, stroke, spinal cord injury, amyotrophic lateral sclerosis, traumatic brain injury, and Alzheimer's disease. In particular, inhibition of the cAMP-specific PDE4 subfamily is widely studied because of its high expression in the CNS. So far, the clinical translation of full PDE4 inhibitors has been hampered because of dose-limiting side effects. Hence, focusing on signaling cascades downstream activated upon PDE4 inhibition presents a promising strategy, offering novel and pharmacologically safe targets for treating CNS disorders. Yet, the underlying downstream signaling pathways activated upon PDE(4) inhibition remain partially elusive. This review provides a comprehensive overview of the existing knowledge regarding downstream mediators of cAMP signaling induced by PDE4 inhibition or cAMP stimulators. Furthermore, we highlight existing gaps and future perspectives that may incentivize additional downstream research concerning PDE(4) inhibition, thereby providing novel therapeutic approaches for CNS disorders.

Therapeutic Implications of Targeting YY1 in Glioblastoma

The transcription factor Yin Yang 1 (YY1) plays a pivotal role in the pathogenesis of glioblastoma multiforme (GBM), an aggressive form of brain tumor. This review systematically explores the diverse roles of YY1 overexpression and activities in GBM, including its impact on the tumor microenvironment (TME) and immune evasion mechanisms. Due to the poor response of GBM to current therapies, various findings of YY1-associated pathways in the literature provide valuable insights into novel potential targeted therapeutic strategies. Moreover, YY1 acts as a significant regulator of immune checkpoint molecules and, thus, is a candidate therapeutic target in combination with immune checkpoint inhibitors. Different therapeutic implications targeting YY1 in GBM and its inherent associated challenges encompass the use of nanoparticles, YY1 inhibitors, targeted gene therapy, and exosome-based delivery systems. Despite the inherent complexities of such methods, the successful targeting of YY1 emerges as a promising avenue for reshaping GBM treatment strategies, presenting opportunities for innovative therapeutic approaches and enhanced patient outcomes.

Olfactory marker protein regulates adipogenesis via the cAMP-IκBα pathway

Olfactory marker protein (OMP) regulates olfactory transduction and is also expressed in adipose tissue. Since it serves as a regulatory buffer for cyclic AMP (cAMP) levels, we hypothesized that it plays a role in modulating adipocyte differentiation. To determine the role of OMP in adipogenesis, we examined the differences in body weight, adipose tissue mass, and adipogenic or thermogenic gene expression between high-fat diet-fed control and Omp-knockout (KO) mice. cAMP production, adipogenic gene expression, and cAMP response element binding protein (CREB) phosphorylation were measured during the differentiation of 3T3-L1 preadipocytes and mouse embryonic fibroblasts (MEFs). RNA sequencing was performed to determine the gene expression patterns responsible for the reduction in adipogenesis when Omp was deleted. Body weight, adipose tissue mass, and adipocyte size decreased in Omp-KO mice. Furthermore, cAMP production and CREB phosphorylation reduced during adipogenesis induced in Omp-/- MEFs, and the Nuclear factor kappa B was activated due to significantly reduced expression of its inhibitor. Collectively, our results suggest that loss of OMP function inhibits adipogenesis by affecting adipocyte differentiation.

AKIP1 accelerates glioblastoma progression through stabilizing EGFR expression

A Kinase Interacting Protein 1 (AKIP1) is found to be overexpressed in a variety of human cancers and associated with patients' worse prognosis. Several studies have established AKIP1's malignant functions in tumor metastasis, angiogenesis, and chemoradiotherapy resistance. However, the mechanism of AKIP1 involved in accelerating glioblastoma (GBM) progression remains unknown. Here, we showed that the expression of AKIP1 was positively correlated with the glioma pathological grades. Down-regulating AKIP1 greatly impaired the proliferation, colony formation, and tumorigenicity of GBM cells. In terms of the mechanism, AKIP1 cooperates with transcriptional factor Yin Yang 1 (YY1)-mediated Heat Shock Protein 90 Alpha Family Class A Member 1 (HSP90AA1) transcriptional activation, enhancing the stability of Epidermal Growth Factor Receptor (EGFR). YY1 was identified as a potential transcriptional factor of HSP90AA1 and directly interacts with AKIP1. The overexpression of HSP90α significantly reversed AKIP1 depletion incurred EGFR instability and the blocked cell proliferation. Moreover, we further investigated the interacted pattern between EGFR and HSP90α. These findings established that AKIP1 acted as a critical oncogenic factor in GBM and uncovered a novel regulatory mechanism in EGFR aberrant expression.

A-Kinase Interacting Protein 1 Knockdown Restores Chemosensitivity via Inactivating PI3K/AKT and β-Catenin Pathways in Anaplastic Thyroid Carcinoma

Background

A-kinase interacting protein 1 (AKIP1) promotes tumor progression and chemoresistance in several malignancies; meanwhile, it is related to higher tumor size and recurrence risk of papillary thyroid carcinoma, while the role of AKIP1 in anaplastic thyroid carcinoma (ATC) is unclear. The aim of this study is to explore the effect of AKIP1 knockdown on cell malignant behaviors and doxorubicin resistance in ATC.

Methods

AKIP1 knockdown was conducted in ATC cell lines (8505C and CAL-62 cells) by siRNA; then, cell viability, apoptosis, invasion, PI3K/AKT and β-catenin pathways, and doxorubicin sensitivity were detected. Subsequently, doxorubicin-resistant 8505C cells (8505C/Dox) were established. Additionally, AKIP1 was modified in 8505C and 8505C/Dox cells that underwent doxorubicin treatment by siRNA or overexpression plasmid, followed by cellular function and pathway detection.

Results

AKIP1 was elevated in FRO, 8505C, CAL-62, and KHM-5M cells compared to control cells (all p < 0.05). Subsequently, AKIP1 knockdown elevated apoptosis, inhibited viability and invasion, and inactivated PI3K/AKT and β-catenin pathways in 8505C and CAL-62 cells (all p < 0.05). AKIP1 knockdown decreased relative cell viability in doxorubicin-treated 8505C and CAL-62 cells; then, AKIP1 was elevated in 8505C/Dox cells compared to 8505C cells (all p < 0.05). Furthermore, AKIP1 knockdown restored doxorubicin sensitivity (reflected by decreased cell viability and invasion, and increased apoptosis), but inactivated PI3K/AKT and β-catenin pathways in doxorubicin-treated 8505C/Dox cells. However, AKIP1 overexpression presented an opposite effect on these functions and pathways in doxorubicin-treated 8505C cells.

Conclusion

AKIP1 knockdown decreases cell survival and invasion while promoting sensitivity to doxorubicin via inactivating PI3K/AKT and β-catenin pathways in ATC.

cAMP Signaling in Cancer: A PKA-CREB and EPAC-Centric Approach

Cancer is one of the most common causes of death globally. Despite extensive research and considerable advances in cancer therapy, the fundamentals of the disease remain unclear. Understanding the key signaling mechanisms that cause cancer cell malignancy may help to uncover new pharmaco-targets. Cyclic adenosine monophosphate (cAMP) regulates various biological functions, including those in malignant cells. Understanding intracellular second messenger pathways is crucial for identifying downstream proteins involved in cancer growth and development. cAMP regulates cell signaling and a variety of physiological and pathological activities. There may be an impact on gene transcription from protein kinase A (PKA) as well as its downstream effectors, such as cAMP response element-binding protein (CREB). The position of CREB downstream of numerous growth signaling pathways implies its oncogenic potential in tumor cells. Tumor growth is associated with increased CREB expression and activation. PKA can be used as both an onco-drug target and a biomarker to find, identify, and stage tumors. Exploring cAMP effectors and their downstream pathways in cancer has become easier using exchange protein directly activated by cAMP (EPAC) modulators. This signaling system may inhibit or accelerate tumor growth depending on the tumor and its environment. As cAMP and its effectors are critical for cancer development, targeting them may be a useful cancer treatment strategy. Moreover, by reviewing the material from a distinct viewpoint, this review aims to give a knowledge of the impact of the cAMP signaling pathway and the related effectors on cancer incidence and development. These innovative insights seek to encourage the development of novel treatment techniques and new approaches.

Specific MRP4 Inhibitor Ceefourin-1 Enhances Apoptosis Induced by 6-Mercaptopurine in Jurkat Leukemic Cells, but Not in Normal Lymphoblast Cell Line CRL-1991

Background and objectives: The multidrug resistance protein 4 (MRP4) is a member of the ABC transporter, which has been extensively related to many types of cancer including leukemia. MRP4 overexpression and activity over the efflux of some chemotherapeutic drugs are the main causes of chemoresistance. 6-mercaptopurine (6-MP) is a chemotherapeutic drug widely used in the consolidation and maintenance phases of leukemia treatment. However, 6-MP is a substrate of MRP4, which decreases its chemotherapeutic efficacy. Current research is focused on the development of MRP4 inhibitors to combat chemoresistance by allowing the accumulation of the drug substrates inside the cells. To date, the only specific MRP4 inhibitor that has been developed is ceefourin-1, which has been reported to inhibit MRP4 in many cancer cells and which makes it an excellent candidate to enhance the activity of 6-MP in a combined treatment in vitro of leukemic cells. Materials and methods: in the present work, we determined the enhancing activity of ceefourin-1 on the antiproliferative and apoptotic effect of 6-MP in leukemic Jurkat cells by trypan blue assay and flow cytometry. Besides, we determined the 6-MP and ceefourin-1 binding sites into MRP4 by molecular docking and molecular dynamics. Results: ceefourin-1 enhanced the apoptotic activity of 6-MP in Jurkat cells, while in CRL-1991 cells both antiproliferative and apoptotic effect were significantly lower. Ceefourin-1 additively cooperates with 6-MP to induce apoptosis in leukemic cells, but normal lymphoblast CRl-1991 showed resistance to both drugs. Conclusion: ceefourin-1 and 6-MP cooperates to trigger apoptosis in leukemic Jurkat cells, but the full mechanism needs to be elucidated in further works. In addition, our perspective is to test the cooperation between ceefourin-1 and 6-MP in samples from patients and healthy donnors.

A-Kinase Interacting Protein 1 Promotes Cell Invasion and Stemness via Activating HIF-1α and β-Catenin Signaling Pathways in Gastric Cancer Under Hypoxia Condition

Background

A-Kinase interacting protein 1 (AKIP1) relates to gastric cancer growth, metastasis, and prognosis, while its regulation on gastric cancer invasion and stemness under hypoxia microenvironment is not reported. Therefore, this study aimed to explore this topic to uncover AKIP1’s role in gastric cancer under hypoxia.

Methods

Gastric cancer cell lines AGS and MKN45 were cultured under hypoxia condition, then transfected with AKIP1 or negative control (NC) overexpression plasmid or AKIP1 or NC knockdown plasmid. Furthermore, rescue experiments were conducted by transfecting HIF-1α or β-catenin overexpression plasmid, combined with AKIP1 or NC knockdown plasmid. Afterward, cell invasion, CD133⁺ cell proportion, sphere number/1,000 cells, and HIF-1α and β-catenin pathways were measured.

Results

The invasive cell count, CD133⁺ cell proportion, and sphere number/1,000 cells were enhanced in both AGS cells and MKN45 cells under hypoxia, and AKIP1 expression was also elevated. AKIP1 knockdown inhibited cell invasion, CD133⁺ cell proportion, sphere number/1,000 cells, HIF-1α, vascular endothelial growth factor (VEGF), β-catenin, and calcium-binding protein (CBP) expressions in AGS cells and MKN45 cells under hypoxia, while AKIP1 overexpression presented with the opposite effect. Then, in rescue experiments, HIF-1α overexpression and β-catenin overexpression both promoted cell invasion, CD133⁺ cell proportion, and sphere number/1,000 cells, which also attenuated the effect of AKIP1 knockdown on these functions in AGS cells and MKN45 cells.

Conclusion

AKIP1 promotes cell invasion and stemness via activating HIF-1α and β-catenin signaling pathways in gastric cancer under hypoxia condition.

Screening and Identification of Human Endogenous Retrovirus-K mRNAs for Breast Cancer Through Integrative Analysis of Multiple Datasets

Objective

Human endogenous retroviruses (HERVs) make up 8% of the human genome. HERVs are biologically active elements related to multiple diseases. HERV-K, a subfamily of HERVs, has been associated with certain types of cancer and suggested as an immunologic target in some tumors. The expression levels of HERV-K in breast cancer (BCa) have been studied as biomarkers and immunologic therapeutic targets. However, HERV-K has multiple copies in the human genome, and few studies determined the transcriptional profile of HERV-K copies across the human genome for BCa.

Methods

Ninety-one HERV-K indexes with entire proviral sequences were used as the reference database. Nine raw sequencing datasets with 243 BCa and 137 control samples were mapped to this database by Salmon software. The differential proviral expression across several groups was analyzed by DESeq2 software.

Results

First, the clustering of each dataset demonstrated that these 91 HERV-K proviruses could well cluster the BCa and control samples when the normal controls were normal cells or healthy donor tissues. Second, several common HERV-K proviruses that are closely related with BCa risk were significantly differentially expressed (p_adj < 0.05 and absolute log2FC > 1.5) in the tissues and cell lines. Additionally, almost all the HERV-K proviruses had higher expression in BCa tissue than in healthy donor tissue. Notably, we first found the expression of 17p13.1 provirus that located with TP53 should regulate TP53 expression in ER+ and HER2+ BCa.

Conclusion

The expression profiling of these 91 HERV-K proviruses can be used as biomarkers to distinguish individuals with BCa and healthy controls. Some proviruses, especially 17p13.1, were strongly associated with BCa risk. The results suggest that HERV-K expression profiles may be appropriate biomarkers and targets for BCa.

Cell-Penetrating Peptides Predicted From CASC3, AKIP1, and AHRR Proteins

Peptides can be used as research tools and for diagnostic or therapeutic applications. Peptides, alongside small molecules and antibodies, are used and are gaining further interest as protein-protein interaction (PPI) modulators. Peptides have high target specificity and high affinity, but, unlike small molecule modulators, they are not able to cross the cell membranes to reach their intracellular targets. To overcome this limitation, the special property of the cell-penetrating peptides (CPPs) could benefit their cause. CPPs are a class of peptides that can enter the cells and with them also deliver the attached cargoes. Today, with the advancement of in silico prediction tools and the availability of protein databases, designing new and multifunctional peptides that are able to reach intracellular targets and inhibit certain cellular processes in a very specific manner is reachable. Although there are several efficient CPP sequences already known, the discovery of new CPPs is crucial for the development of efficient delivery methods for both biotechnological and therapeutic applications. In this work, we chose 10 human nuclear proteins from which we predicted new potential CPP sequences by using three different CPP predictors: cell-penetrating peptide prediction tool, CellPPD, and SkipCPP-Pred. From each protein, one predicted CPP sequence was synthesized and its internalization into cells was assessed. Out of the tested sequences, three peptides displayed features characteristic to CPPs. These peptides and also the predicted peptide sequences could be used to design and modify new CPPs. In this work, we show that we can use protein sequences as input for generating new peptides with cell internalization properties. Three new CPPs, AHRR_8-24, CASC3_251-264, and AKIP1_27-37, can be further used for the delivery of other cargoes or designed into multifunctional peptides with capability of internalizing cells.

PKA and AKIP1 interact to mediate cAMP-driven COX-2 expression: A potentially pivotal interaction in preterm and term labour

Previously, we showed that cAMP increased COX-2 expression in myometrial cells via MAPK. Here, we have extended these observations, using primary myometrial cell cultures to show that the cAMP agonist, forskolin, enhances IL-1β-driven COX-2 expression. We then explored the role of A-kinase interacting protein (AKIP1), which modulates the effect of PKA on p65 activation. AKIP1 knockdown reversed the effect of forskolin, such that its addition inhibited IL-1β-induced COX-2 mRNA expression and reduced the IL-1β-induced increase in nuclear levels of p65 and c-jun. Forskolin alone and with IL-1β increased IκBα mRNA expression suggesting that in the context of inflammation and in the presence of AKIP1, cAMP enhances p65 activation. AKIP1 knockdown reversed these changes. Interestingly, AKIP1 knockdown had minimal effect on the ability of forskolin to repress either basal OTR expression or IL-1β-stimulated OTR mRNA expression. AKIP1 was up-regulated by IL-1β, but not stretch and was repressed by cAMP. The mRNA expression of AKIP1 increased in early labour in tandem with an increase in COX-2 mRNA and protein. AKIP1 protein levels were also increased with inflammation and stretch-induced preterm labour. Our results identify a second important cAMP effector-switch occurring at term in human myometrium and suggest that a hitherto unrecognized interaction may exist between AKIP1, NFκB and AP-1. These data add to the proposition that cAMP acts as a key regulator of human myometrial contractility.

TNF-α/NF-κB signaling epigenetically represses PSD4 transcription to promote alcohol-related hepatocellular carcinoma progression

BACKGROUND

Chronic alcohol consumption is more frequently associated with advanced, aggressive hepatocellular carcinoma (HCC) tumors. Alcohol adversely impacts ER/Golgi membrane trafficking and Golgi protein N-glycosylation in hepatocytes; these effects have been attributed (in part) to dysregulated adenosine diphosphate-ribosylation factor (ARF) GTPase signaling. Here, we investigated the role of the ARF GTPase guanine exchange factor PSD4 in HCC progression.

METHODS

R-based bioinformatics analysis was performed on publicly available array data. Modulating gene expression was accomplished via lentiviral vectors. Gene expression was analyzed using quantitative real-time PCR and immunoblotting. PSD4 promoter methylation was assessed using quantitative methylation-specific PCR. Phospho-p65(S276)/DNMT1 binding to the PSD4 promoter was analyzed via chromatin immunoprecipitation. We constructed ethanol/DEN-induced and DEN only-induced transgenic murine models of HCC.

RESULTS

We identified PSD4 as a hypermethylated, suppressed gene in alcohol-related HCC tumors; however, PSD4 was not dysregulated in all-cause HCC tumors. Certain HCC cell lines also displayed varying degrees of PSD4 downregulation. PSD4 overexpression or knockdown decreased and increased cell migration and invasiveness, respectively. Mechanistically, PSD4 transcription was repressed by TNF-α-induced phospho-p65(S276)'s recruitment of DNA methyltransferase 1 (DNMT1), resulting in PSD4 promoter methylation. PSD4 inhibited pro-EMT CDC42 activity, resulting in downregulation of E-cadherin and upregulation of N-cadherin and vimentin. Hepatocyte-specific PSD4 overexpression reduced ethanol/DEN-induced HCC tumor progression and EMT marker expression in vivo.

CONCLUSIONS

PSD4 is a hypermethylated, suppressed gene in alcohol-related HCC tumors that negatively modulated pro-EMT CDC42 activity. Furthermore, we present a novel phospho-NF-κB p65(S276)/DNMT1-mediated promoter methylation mechanism by which TNF-α/NF-κB signaling represses PSD4 transcription in HCC cells.

AKIP1 promotes glioblastoma viability, mobility and chemoradiation resistance via regulating CXCL1 and CXCL8 mediated NF-κB and AKT pathways

This study aimed to investigate the interaction of A-kinase-interacting protein 1 (AKIP1) with C-X-C motif chemokine ligand (CXCL)1, CXCL2, CXCL8, and their effects on regulating glioblastoma multiforme (GBM) malignant behaviors. AKIP1 expression was modified by pcDNA and pGPH1 vectors in U-87 MG and U-251 MG cells. Subsequently, multiple compensative experiments were conducted via adding CXCL1, CXCL2 and CXCL8 in the pGPH1-AKIP1 (AKIP1 knockdown) transfected U-87 MG and U-251 MG cells, respectively. Furthermore, AKIP1, CXCL1/2/8 expressions in 10 GBM and 10 low-grade glioma (LGG) tumor samples were detected. AKIP1 was elevated in various GBM cell lines compared to normal human astrocytes. AKIP1 overexpression promoted U-87 MG and U-251 MG cell proliferation and invasion while inhibited apoptosis; and it enhanced chemoresistance to temozolomide (but not cisplatin) and radiation resistance; then AKIP1 knockdown showed the opposite effects. Meanwhile, AKIP1 positively regulated CXCL1/2/8, NF-κB pathway, AKT pathway and PD-L1 expression. Further multiple compensative experiments uncovered that CXCL1 and CXCL8 promoted proliferation, invasion, chemoradiation resistance, NF-κB pathway, AKT pathway and PD-L1 expression in U-87 MG and U-251 MG cells, also in pGPH1-AKIP1 (AKIP1 knockdown) transfected U-87 MG and U-251 MG cells; although CXCL2 exhibited similar treads, but its effect was much weaker. Besides, NF-κB pathway inhibitor and AKT pathway inhibitor attenuated the effect of CXCL1&CXCL8 on promoting GBM cell malignant behaviors. Clinically AKIP1 and CXCL1/8 were elevated in GBM compared to LGG tumor samples, and they were inter-correlated. AKIP1 promotes GBM viability, mobility and chemoradiation resistance via regulating CXCL1 and CXCL8 mediated NF-κB and AKT pathways.

Upregulation of a kinase interacting protein 1 in tongue squamous cell carcinoma correlates with lymph node metastasis and poor overall survival

A kinase interacting protein 1 (AKIP1) is upregulated in cancer cells/tissues and associated with deteriorative tumor features, while it has not been investigated in tongue squamous cell carcinoma (TSCC). The goal of this study was to measure AKIP1 expression and analyze its correlation with clinical feature and prognosis in TSCC patients.We retrospectively reviewed 194 TSCC patients, whose formalin fixed paraffin-embedded (FFPE) tumor tissue specimens and paired adjacent tissue specimens were accessible for AKIP1 detection by immunohistochemistry (IHC). Whereas only 107 patients whose fresh-frozen tumor tissue and paired fresh-frozen adjacent tissue that were still available in storage were included for AKIP1 mRNA detection by real-time reverse transcription quantitative polymerase chain reaction (RT-qPCR).AKIP1 expression (both the protein detected by IHC and mRNA detected by RT-qPCR) was higher in TSCC tissue than that in adjacent tissue. In addition, both tumor AKIP1 mRNA and protein expressions were correlated with advanced N stage and TNM stage, while they were not correlated with other clinical features in TSCC patients. As for survival, there was a correlation of AKIP1 mRNA with poor overall survival (OS), while the correlation of AKIP1 protein expression with OS was of limited statistical significance.There is an upregulation of AKIP1 in TSCC and it correlates with lymph node metastasis as well as unfavorable prognosis in TSCC patients.

Sustained Inhibition of NF-κB Activity Mitigates Retinal Vasculopathy in Diabetes

This study investigated the effects of long-term NF-κB inhibition in mitigating retinal vasculopathy in a type 1 diabetic mouse model (Akita, Ins2^Akita). Akita and wild-type (C57BL/6J) male mice, 24 to 26 weeks old, were treated with or without a selective inhibitor of NF-κB, 4-methyl-N1-(3-phenyl-propyl) benzene-1,2-diamine (JSH-23), for 4 weeks. Treatment was given when the mice were at least 24 weeks old. Metabolic parameters, key inflammatory mediators, blood-retinal barrier junction molecules, retinal structure, and function were measured. JSH-23 significantly lowered basal glucose levels and intraocular pressure in Akita. It also mitigated vascular remodeling and microaneurysms significantly. Optical coherence tomography of untreated Akita showed thinning of retinal layers; however, treatment with JSH-23 could prevent it. Electroretinogram demonstrated that A- and B-waves in Akita were significantly smaller than in wild type mice, indicating that JSH-23 intervention prevented loss of retinal function. Protein levels and gene expression of key inflammatory mediators, such as NOD-like receptor family pyrin domain-containing 3, intercellular adhesion molecule-1, inducible nitric oxide synthase, and cyclooxygenase-2, were decreased after JSH-23 treatment. At the same time, connexin-43 and occludin were maintained. Vision-guided behavior also improved significantly. The results show that reducing inflammation could protect the diabetic retina and its vasculature. Findings appear to have broader implications in treating not only ocular conditions but also other vasculopathies.

A-kinase interacting protein 1 is sufficiently expressed and positively associates with WHO grade, meanwhile predicts unfavorable overall survival independently in glioma patients

The present study aimed to investigate the association of A-kinase interacting protein 1 (AKIP1) with clinical characteristics, and further explore the prognostic value of AKIP1 in glioma patients.Totally 168 glioma patients who underwent tumor resection were analyzed, and their tumor tissue specimens were acquired for the detection of AKIP1 expression by immunohistochemistry (IHC), which was scored by a semi-quantitative method considering staining intensity and staining density.According to AKIP1 expression in tumor tissues of glioma patients, there were 65 (38.7%) patients with AKIP1 low expression (IHC score 0-3), 48 (28.6%) patients with AKIP1 high + expression (IHC score 4-6), 42 (25.0%) patients with AKIP1 high++ expression (IHC score 7-9) and 13 (7.7%) patients with AKIP1 high+++ expression (IHC score 10-12), respectively. AKIP1 expression was positively associated with World Health Organization grade. Overall survival (OS) was the lowest in the patients with AKIP1 high+++ expression, followed by those with AKIP1 high++ expression and those with AKIP1 high+ expression, and highest in those with AKIP1 low expression. Further subgroup analysis exhibited that AKIP1 expression was negatively associated with OS especially in high-grade glioma patients. In addition, AKIP1 expression was negatively associated with OS in all subgroups of patients with/without adjuvant radiotherapy, with/without adjuvant chemotherapy. Further multivariate Cox's regression exhibited that AKIP1 high expression was an independent predictive factor for worse OS.AKIP1 presents with the potential to be a novel biomarker for tumor management and prognosis surveillance in glioma patients.

H89 Treatment Reduces Intestinal Inflammation and Candida albicans Overgrowth in Mice

Deregulation of the dynamic crosstalk between the gut microbiota, intestinal epithelial cells, and immune cells is critically involved in the development of inflammatory bowel disease and the overgrowth of opportunistic pathogens, including the human opportunistic fungus Candida albicans. In the present study, we assessed the effect of N-[2-(p-bromocinnamylamino)ethyl]-5-isoquinolinesulfonamide (H89), a protein kinase A inhibitor, on the migration of macrophages to C. albicans through dextran sulphate sodium (DSS)-challenged Caco-2 cells. We also investigated the impact of H89 on intestinal inflammation and C. albicans clearance from the gut, and determined the diversity of the gut microbiota in a murine model of DSS-induced colitis. H89 reduced the migration of macrophages to C. albicans through DSS-challenged Caco-2 cells. In addition, H89 decreased C. albicans viability and diminished the expression of pro-inflammatory cytokines and innate immune receptors in macrophages and colonic epithelial Caco-2 cells. In mice with DSS-induced colitis, H89 attenuated the clinical and histological scores of inflammation and promoted the elimination of C. albicans from the gut. H89 administration to mice decreased the overgrowth of Escherichia coli and Enterococcus faecalis populations while Lactobacillus johnsonii populations increased significantly. Overall, H89 reduced intestinal inflammation and promoted the elimination of C. albicans from the gut.

Correlation of A-Kinase Interacting Protein 1 With Clinical Features, Treatment Response, and Survival Profiles in Patients With Multiple Myeloma

Objective:

The present study aimed to detect A-kinase interacting protein 1 expression and further explore the association of A-kinase interacting protein 1 with clinical features and prognosis in patients with multiple myeloma.

Methods:

Totally, 152 de novo symptomatic patients with multiple myeloma and 30 healthy donors were enrolled. Bone marrow mononuclear cells derived plasma cells were collected from patients with multiple myeloma before initial treatment and from healthy donors on the enrollment, respectively, and then A-kinase interacting protein 1 protein/messenger RNA expressions were detected by Western blot and reverse transcription quantitative polymerase chain reaction. Treatment response (complete response and overall response rate) was assessed, and survival profiles (progression-free survival and overall survival) were calculated in patients with multiple myeloma.

Results:

A-kinase interacting protein 1 protein/messenger RNA expressions were elevated in patients with multiple myeloma compared to healthy donors, and A-kinase interacting protein 1 (area under the curve: 0.809, 95% confidence interval: 0.726-0.891)/messenger RNA (area under the curve: 0.839, 95% confidence interval: 0.764-0.914) presented good value in differentiating patients with multiple myeloma from healthy donors. In patients with multiple myeloma, A-kinase interacting protein 1 /messenger RNA expressions negatively correlated with albumin while positively correlated with Beta-2-microglobulin, lactate dehydrogenase, International Staging System stage, and t (4;14). Meanwhile, there were 39 (25.7%) complete response patients, 113 (74.3%) noncomplete response patients, 112 (73.7%) overall response rate patients, and 40 (26.3%) nonoverall response rate patients. Complete response and overall response rates were decreased in patients with high A-kinase interacting protein 1 compared to patients with low A-kinase interacting protein 1. Additionally, progression-free survival and overall survival were reduced in patients with high A-kinase interacting protein 1 compared to patients with low A-kinase interacting protein 1.

Conclusion:

A-kinase interacting protein 1 exhibits the potency as a biomarker for multiple myeloma progression and prognosis, which implies the clinical application of A-kinase interacting protein 1 in multiple myeloma management.

A kinase-interacting protein 1 may serve as a potential biomarker for deteriorative tumor features and poor prognosis in gastric cancer patients

OBJECTIVE

This study aimed to explore the association of A kinase-interacting protein 1 (AKIP1) expression with clinicopathological characteristics and prognosis in gastric cancer patients.

METHODS

Data of 260 gastric cancer patients were retrospectively reviewed. AKIP1 expression in tumor tissue and non-cancerous tissue specimens was detected by immunohistochemistry and semi-quantitatively scored according to the staining intensity and density. Moreover, the clinicopathological features were retrieved, and disease-free survival (DFS) and overall survival (OS) were calculated.

RESULTS

A kinase-interacting protein 1 expression was increased in tumor tissues compared with non-cancerous tissues (P < .001). In terms of tumor features, tumor AKIP1 high expression correlated with elevated T stage (P < .001) and raised TNM stage (P = .042), while did not correlate with pathological grade (P > .999), tumor size (P = .060), N stage (P = .180), or tumor location (P > .999). Meanwhile, tumor AKIP1 was not associated with the non-tumor features either. Kaplan-Meier curves disclosed that AKIP1 high expression patients had shorter DFS (P = .004) and OS (P = .043) compared with AKIP1 low expression patients. Univariate Cox's regression showed that AKIP1 high expression correlated with shorter DFS (P = .005, hazard ratio [HR] = 1.635) and OS (P = .046, HR = 1.519), whereas multivariate Cox's regression displayed that AKIP1 did not independently predict worse DFS (P = .172, HR = 1.276) or shorter OS (P = .433, HR = 1.183).

CONCLUSION

A kinase-interacting protein 1 may serve as a potential biomarker for deteriorative tumor features and poor prognosis in gastric cancer patients.

A-kinase interacting protein 1 high expression correlates with advanced tumor stage and poor overall survival in surgical patients with clear cell renal cell carcinoma

The present study aimed to detect the A-kinase interacting protein 1 (AKIP1) expression in clear cell renal cell carcinoma (ccRCC) tumor tissues and adjacent tissues, and further investigate the correlation of tumor AKIP1 expression with clinicopathological features and survival profile in ccRCC patients.Totally 210 ccRCC patients who underwent resection were retrospectively reviewed, and their tumor and adjacent tissue specimens were acquired for immunohistochemical detection of AKIP1 expression. The survival data of patients were collected for overall survival (OS) assessment.AKIP1 was upregulated in ccRCC tumor tissues compared with adjacent tissues (P < .001). Tumor AKIP1 expression was positively associated with T stage (P = .019), N stage (P = .032), and TNM stage (P = .005) in ccRCC patients. According to AKIP1 expression in tumor tissues, all patients were grouped as AKIP1 low and high expression (AKIP1 high expression were further divided into AKIP1 high+, high++, and high+++ expression). OS was the lowest in the patients with AKIP1 high+++ expression, followed by those with AKIP1 high++ expression and AKIP1 high+ expression, and then patients with AKIP1 low expression (P < .001). Furthermore, multivariate Cox regression exhibited tumor AKIP1 high expression (P = .017), age (>60 years) (P = .030), pathological grade (G2/G3 vs G1) (P = .037), and TNM stage (II/III vs I) (P < .001) were independent predictive factors for decreased OS in ccRCC patients.AKIP1 presents potency to be a novel biomarker for tumor progression and prognosis surveillance in ccRCC.

A-kinase interacting protein 1 (AKIP1) associates with advanced overall disease condition, tumor properties, and unfavorable prognosis in hepatocellular carcinoma patients

OBJECTIVE

The presented study aimed to investigate the association of A-kinase interacting protein 1 (AKIP1) expression with tumor properties, liver functions, cancer markers, and overall survival (OS) of hepatocellular carcinoma (HCC) patients.

METHODS

A total of 432 HCC patients receiving surgery were retrospectively reviewed in our study. Clinical characteristics of patients were obtained. Tumor tissue specimens of all patients were collected, and AKIP1 expression was evaluated by immunohistochemistry (IHC) assay. OS was assessed, and the median follow-up duration was 35.0 months. AKIP1 high expression was defined as total IHC score more than 3 and was further graded as AKIP1 high+ (IHC 4-6), AKIP1 high++ (IHC 7-9), and AKIP1 high+++ (IHC 10-12).

RESULTS

About 265 (61.3%) patients presented with AKIP1 low expression and 167 (38.7%) patients had AKIP1 high expression. AKIP1 high expression correlated with higher performance status score (P = .006), largest tumor size ≥5.0 cm (P < .001), Barcelona clinic liver cancer (BCLC) stage B (vs stage A; P = .024), increased alpha-fetoprotein level (P = .036), and higher carbohydrate antigen 199 level (P < .001). AKIP1 high expression (P < .001) and increased AKIP1 expression grade (P < .001) both correlated with worse OS, and Cox's regression analyses revealed that AKIP1 high expression (P < .001) was an independent predictive factor for shorter OS. In subgroup analysis, AKIP1 high expression and more advanced AKIP1 expression grade associated with worse OS in both BCLC stage A subgroup patients (both P < .001) and BCLC stage B subgroup patients (both P < .001), respectively.

CONCLUSION

AKIP1 is a novel and promising biomarker for disease monitoring and prognosis in HCC patients.

A-kinase-interacting protein 1 promotes EMT and metastasis via PI3K/Akt/IKKβ pathway in cervical cancer

Overexpression of A‐kinase‐interacting protein 1 (AKIP1) has been reported in prostate and breast cancers. Nevertheless, the clinical potential of AKIP1 during the development of cervical cancer (CC) remains unclear. A series of experiments involving BdU, colony formation, wound healing and cell invasion assays were performed to determine cell proliferation, migration and invasion, respectively. Gene expression changes were validated by qRT‐PCR, Western blotting and immunocytochemistry. We found that AKIP1 expression is increased in CC cell lines and tissue specimens from CC patients. The elevated AKIP1 expression in primary tumours was related to lymph node metastasis in CC patients. In addition, we observed that overexpression of AKIP1 promotes CC cell proliferation. Enhanced expression of AKIP1 facilitated the migration and invasion of CC cells by inducing NF‐κB‐dependent epithelial‐mesenchymal transition (EMT). Moreover, mechanistic investigations revealed that AKIP1 induced nuclear translocation and phosphorylation of the p65 NF‐κB subunit through the PI3K/Akt/IKKβ pathway. Conversely, enhanced expression of phosphatase and tensin homologue (PTEN) inhibited this signalling pathway and restored an epithelial phenotype to CC cells in the presence of overexpressed AKIP1. Our results indicate that AKIP1 promotes the EMT and metastasis in CC by activating NF‐κB signalling through the PI3K/Akt/IKKβ pathway, suggesting that AKIP1 could be a pivotal regulator of an EMT axis in CC.

Significance of the study

AKIP1 expression in the samples of CC patients and in in vitro tumour cell lines provides evidence that expression of AKIP1 in CC contributes to cancer progression. Our findings indicate that AKIP1 promotes the epithelial‐mesenchymal transition and metastasis in CC by activating NF‐κB signalling through the PI3K/Akt/IKKβ pathway, suggesting that AKIP1 is a pivotal regulator of an EMT axis in CC. AKIP1 could be implicated as a potential therapeutic target as well as a valuable biomarker for evaluating prognosis for patients with CC.

Identification of A-kinase interacting protein 1 as a potential biomarker for risk and prognosis of acute myeloid leukemia

Background

This study aimed to investigate the correlation of A‐kinase interacting protein 1 (AKIP1) expression with disease risk, clinical characteristics, and prognosis of acute myeloid leukemia (AML).

Methods

291 de novo AML patients and 97 controls were consecutively recruited, and bone marrow samples were collected to detect AKIP1 expression using quantitative polymerase chain reaction prior to initial treatment. Treatment response, event‐free survival (EFS), and overall survival (OS) in AML patients were evaluated.

Results

A‐kinase interacting protein 1 expression was higher in AML patients than that in controls; meanwhile, receiver operating characteristic curve displayed that AKIP1 was able to distinguish AML patients from controls (area under the curve:0.772, 95%CI: 0.720‐0.823). Among AML patients, AKIP1 high expression was correlated with −7 or 7q−, monosomal karyotype, and worse risk stratification. Moreover, AKIP1 expression was negatively correlated with complete remission achievement, while no correlation of AKIP1 expression with hematopoietic stem cell transplantation achievement was observed. AKIP1 high expression was associated with shorter EFS and OS in total patients, and further subgroup analysis exhibited that AKIP1 high expression correlated with worse EFS and OS in intermediate‐risk and poor‐risk patients but not in better‐risk patients. Besides, subsequent analysis revealed that AKIP1 high expression was an independent factor predicting unfavorable EFS and OS.

Conclusion

A‐kinase interacting protein 1 has the potential to be a novel marker for assisting AML management.

Comparative proteomic analysis of different stages of breast cancer tissues using ultra high performance liquid chromatography tandem mass spectrometer

BACKGROUND

Breast cancer is the fifth most prevalent cause of death among women worldwide. It is also one of the most common types of cancer among Malaysian women. This study aimed to characterize and differentiate the proteomics profiles of different stages of breast cancer and its matched adjacent normal tissues in Malaysian breast cancer patients. Also, this study aimed to construct a pertinent protein pathway involved in each stage of cancer.

METHODS

In total, 80 samples of tumor and matched adjacent normal tissues were collected from breast cancer patients at Seberang Jaya Hospital (SJH) and Kepala Batas Hospital (KBH), both in Penang, Malaysia. The protein expression profiles of breast cancer and normal tissues were mapped by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The Gel-Eluted Liquid Fractionation Entrapment Electrophoresis (GELFREE) Technology System was used for the separation and fractionation of extracted proteins, which also were analyzed to maximize protein detection. The protein fractions were then analyzed by tandem mass spectrometry (LC-MS/MS) analysis using LC/MS LTQ-Orbitrap Fusion and Elite. This study identified the proteins contained within the tissue samples using de novo sequencing and database matching via PEAKS software. We performed two different pathway analyses, DAVID and STRING, in the sets of proteins from stage 2 and stage 3 breast cancer samples. The lists of molecules were generated by the REACTOME-FI plugin, part of the CYTOSCAPE tool, and linker nodes were added in order to generate a connected network. Then, pathway enrichment was obtained, and a graphical model was created to depict the participation of the input proteins as well as the linker nodes.

RESULTS

This study identified 12 proteins that were detected in stage 2 tumor tissues, and 17 proteins that were detected in stage 3 tumor tissues, related to their normal counterparts. It also identified some proteins that were present in stage 2 but not stage 3 and vice versa. Based on these results, this study clarified unique proteins pathways involved in carcinogenesis within stage 2 and stage 3 breast cancers.

CONCLUSIONS

This study provided some useful insights about the proteins associated with breast cancer carcinogenesis and could establish an important foundation for future cancer-related discoveries using differential proteomics profiling. Beyond protein identification, this study considered the interaction, function, network, signaling pathway, and protein pathway involved in each profile. These results suggest that knowledge of protein expression, especially in stage 2 and stage 3 breast cancer, can provide important clues that may enable the discovery of novel biomarkers in carcinogenesis.

A-kinase-interacting protein 1 overexpression correlates with deteriorative tumor features and worse survival profiles, and promotes cell proliferation but represses apoptosis in non-small-cell lung cancer

Background

This study aimed to explore the correlation of A‐kinase‐interacting protein 1 (AKIP1) expression with clinical characteristics as well as survival profiles in non‐small‐cell lung cancer (NSCLC) patients, and further investigate its underlying effect on regulating NSCLC cell functions.

Methods

319 NSCLC patients who underwent resection were consecutively reviewed, and AKIP1 expression (in 319 tumor tissues and 145 adjacent tissues) was determined by immunohistochemistry. Disease‐free survival (DFS) and overall survival (OS) were calculated. In vitro, control overexpression, AKIP1 overexpression, control shRNA and AKIP1 shRNA plasmids were transfected into A549 cells to evaluate the effect of AKIP1 on cell proliferation and apoptosis.

Results

A‐kinase‐interacting protein 1 expression was increased in tumor tissues compared to adjacent tissues, and it positively correlated with tumor size, lymph node metastasis and TNM stage in NSCLC patients. Kaplan‐Meier curves displayed that AKIP1 high expression correlated with worse DFS and OS, and multivariate Cox's regression revealed that it was an independent predictive factor for poor survival profiles. In vitro experiments displayed that AKIP1 expression was elevated in PC9 and A549 cells compared to normal lung epithelial cells; moreover, cell proliferation was increased by AKIP1 upregulation but reduced by AKIP1 downregulation, and cell apoptosis was decreased by AKIP1 upregulation but increased by AKIP downregulation in A549 cells. Interestingly, AKIP1 promoted fibronectin and zinc finger E‐box binding homeobox 1 expressions while reduced E‐cadherin expression in A549 cells.

Conclusion

A‐kinase‐interacting protein 1 overexpression correlates with deteriorative tumor features and worse survival profiles and promotes cell proliferation but represses apoptosis in NSCLC.

AKIP1 expression in tumor tissue as a new biomarker for disease monitoring and prognosis in non-small cell lung cancer: Results of a retrospective study

Background

A‐kinase–interacting protein 1 (AKIP1) has been reported as an oncogenetic factor in multiple cancers; however, no study has reported its role in non‐small cell lung cancer (NSCLC) yet. This study aimed to evaluate the expression of AKIP1, and its correlation with tumor characteristics as well as prognosis in patients with NSCLC.

Methods

Four hundred and ninety patients with NSCLC who underwent resection were reviewed, and baseline clinical data were collected. AKIP1 expression in tumor tissue/paired adjacent tissue was detected by immunohistochemistry. Disease‐free survival (DFS) and overall survival (OS) were calculated.

Results

A‐kinase–interacting protein 1 expression was elevated in tumor tissue compared with paired adjacent tissue (P < .001), and high AKIP1 tumor tissue expression was correlated with poor pathological differentiation (P < .001), tumor size >5 cm (P = .001), lymph node metastasis (P = .016), higher TNM stages (P < .001), and abnormal CEA level (>5 ng/mL) (P = .035). DFS was worse in patients with tumor tissue AKIP1 high expression compared with patients who had AKIP1 low expression in total patients (P < .001), TNM stage I (P < .001) and TNM stage III (P < .001) patients. And the OS was also decreased in patients with AKIP1 high expression in total patients (P < .001), TNM stage I patients (P = .001) and TNM stage III patients (P = .004). Moreover, multivariate Cox's proportional hazards regression model analysis revealed that AKIP1 high expression was an independent predictive factor for worse DFS (P < .001) and OS (P < .001).

Conclusion

Tumor tissue AKIP1 expression may have the potential to be a biomarker assisting in disease monitoring and prognosis in NSCLC.

MicroRNAs in breast cancer: Roles, functions, and mechanism of actions

Breast cancer is one of the most lethal malignancies in women in the world. Various factors are involved in the development and promotion of the malignancy; most of them involve changes in the expression of certain genes, such as microRNAs (miRNAs). MiRNAs can regulate signaling pathways negatively or positively, thereby affecting tumorigenesis and various aspects of cancer progression, particularly breast cancer. Besides, accumulating data demonstrated that miRNAs are a novel tool for prognosis and diagnosis of breast cancer patients. Herein, we will review the roles of these RNA molecules in several important signaling pathways, such as transforming growth factor, Wnt, Notch, nuclear factor-κ B, phosphoinositide-3-kinase/Akt, and extracellular-signal-regulated kinase/mitogen activated protein kinase signaling pathways in breast cancer.

Combining CDKN1A gene expression and genome-wide SNPs in a twin cohort to gain insight into the heritability of individual radiosensitivity

Individual variability in response to radiation exposure is recognised and has often been reported as important in treatment planning. Despite many efforts to identify biomarkers allowing the identification of radiation sensitive patients, it is not yet possible to distinguish them with certainty before the beginning of the radiotherapy treatment. A comprehensive analysis of genome-wide single-nucleotide polymorphisms (SNPs) and a transcriptional response to ionising radiation exposure in twins have the potential to identify such an individual. In the present work, we investigated SNP profile and CDKN1A gene expression in blood T lymphocytes from 130 healthy Caucasians with a complex level of individual kinship (unrelated, mono- or dizygotic twins). It was found that genetic variation accounts for 66% (95% CI 37-82%) of CDKN1A transcriptional response to radiation exposure. We developed a novel integrative multi-kinship strategy allowing investigating the role of genome-wide polymorphisms in transcriptomic radiation response, and it revealed that rs205543 (ETV6 gene), rs2287505 and rs1263612 (KLF7 gene) are significantly associated with CDKN1A expression level. The functional analysis revealed that rs6974232 (RPA3 gene), involved in mismatch repair (p value = 9.68e-04) as well as in RNA repair (p value = 1.4e-03) might have an important role in that process. Two missense polymorphisms with possible deleterious effect in humans were identified: rs1133833 (AKIP1 gene) and rs17362588 (CCDC141 gene). In summary, the data presented here support the validity of this novel integrative data analysis strategy to provide insights into the identification of SNPs potentially influencing radiation sensitivity. Further investigations in radiation response research at the genomic level should be therefore continued to confirm these findings.

Targeting Kinase Interaction Networks: A New Paradigm in PPI Based Design of Kinase Inhibitors

BACKGROUND

Kinases are key modulators in regulating diverse range of cellular activities and are an essential part of the protein-protein interactome. Understanding the interaction of kinases with different substrates and other proteins is vital to decode the cell signaling machinery as well as causative mechanism for disease onset and progression.

OBJECTIVE

The objective of this review is to present all studies on the structure and function of few important kinases and highlight the protein-protein interaction (PPI) mechanism of kinases and the kinase specific interactome databases and how such studies could be utilized to develop anticancer drugs.

METHODS

The article is a review of the detailed description of the various domains in kinases that are involved in protein-protein interactions and specific inhibitors developed targeting these PPI domains.

RESULTS

The review has surfaced in depth the interacting domains in key kinases and their features and the roles of PPI in the human kinome and the various signaling cascades that are involved in certain types of cancer.

CONCLUSION

The insight availed into the mechanism of existing peptide inhibitors and peptidomimetics against kinases will pave way for the design and generation of domain specific peptide inhibitors with better productivity and efficiency and the various software and servers available can be of great use for the identification and analysis of protein-protein interactions.

Various AKIP1 expression levels affect its subcellular localization but have no effect on NF-kappaB activation

A-kinase interacting protein 1 (AKIP1) has been shown to interact with a broad range of proteins involved in various cellular processes, including apoptosis, tumorigenesis, and oxidative stress suggesting it might have multiple cellular functions. In this study, we used an epitope-tagged AKIP1 and by combination of immunochemical approaches, microscopic methods and reporter assays we studied its properties. Here, we show that various levels of AKIP1 overexpression in HEK-293 cells affected not only its subcellular localization but also resulted in aggregation. While highly expressed AKIP1 accumulated in electron-dense aggregates both in the nucleus and cytosol, low expression of AKIP1 resulted in its localization within the nucleus as a free, non-aggregated protein. Even though AKIP1 was shown to interact with p65 subunit of NF-kappaB and activate this transcription factor, we did not observe any effect on NF-kappaB activation regardless of various AKIP1 expression level.

Upregulation of AKIP1 contributes to metastasis and progression and predicts poor prognosis of patients with colorectal cancer

Background

A kinase-interacting protein 1 (AKIP1) has been reported to play an important role in the development and progression of cancer. However, the clinicopathological and biological roles of AKIP1 in colorectal cancer (CRC) remain largely unknown. The aim of this study was to investigate AKIP1 protein expression in CRC and determine the correlation between AKIP1 protein expression and clinicopathological features, as well as prognosis in CRC patients.

Materials and methods

AKIP1 protein expression was determined by immunohistochemical analysis using tissue microarrays of CRC. We also used an siRNA approach to knock down AKIP1 expression and determine the effect of AKIP1 on CRC cell migration by transwell analysis.

Results

AKIP1 expression in CRC tissue was significantly higher compared with that of noncancerous colorectal mucosa (P<0.001). Further analysis showed that AKIP1 expression was significantly associated with tumor diameter, TNM stage, and lymph node metastasis (P<0.05). Kaplan–Meier survival analysis demonstrated that patients with a positive AKIP1 expression had significantly poorer overall survival rates when compared with those with negative AKIP1 expression (P=0.031). Multivariate analysis using the Cox proportional hazard model, however, revealed that AKIP1 expression was not a significant independent prognostic factor for CRC. Transwell assay showed that the migration potential of si-AKIP1-transfected cells was significantly reduced when compared with control cells.

Conclusion

Elevated AKIP1 expression may contribute to metastasis and progression of CRC. Moreover, high AKIP1 expression in CRC significantly correlated with a patient’s shorter survival time. Therefore, AKIP1 may be a useful prognostic marker for CRC and a promising novel target for the treatment of CRC.

Remifentanil suppresses increase in interleukin-6 mRNA in the brain by inhibiting cyclic AMP synthesis

PURPOSE

Neuronal inflammation is caused by systemic inflammation and induces cognitive dysfunction. IL-6 plays a crucial role in therapies for neuronal inflammation and cognitive dysfunction. Remifentanil, an ultra-short-acting opioid, controls inflammatory reactions in the periphery, but not in the brain. Therefore, the anti-inflammatory effects of remifentanil in neuronal tissue and the involvement of cAMP in these effects were investigated in the present study.

METHODS

Mice were divided into 4 groups: control, remifentanil, LPS, and LPS + remifentanil. Brain levels of pro-inflammatory cytokine mRNA, and serum levels of corticosterone, catecholamine and IL-6 were measured in the 4 groups. The co-localization of IL-6 and astrocytes in the mouse brain after the LPS injection was validated by immunostaining. LPS and/or remifentanil-induced changes in intracellular cAMP levels in cultured glial cells were measured, and the effects of cAMP on LPS-induced IL-6 mRNA expression levels were evaluated.

RESULTS

Remifentanil suppressed increase in IL-6 mRNA levels in the mouse brain, and also inhibited the responses of plasma IL-6, corticosterone, and noradrenaline in an inflammatory state. In the hypothalamus, IL-6 was localized in the median eminence, at which GFAP immunoreactivity was specifically detected. In cultured cells, remifentanil suppressed increase in IL-6 mRNA levels and intracellular cAMP levels after the administration of LPS, and this enhanced IL-6 mRNA expression in response to LPS.

CONCLUSION

Remifentanil suppressed increase in IL-6 mRNA levels in the brain in an inflammatory state, and this effect may be attributed to its direct action on neuronal cells through the inhibition of intracellular cAMP rather than corticosterone.

Does BCA3 Play a Role in the HIV-1 Replication Cycle?

The cellular role of breast carcinoma-associated protein (BCA3), also known as A-kinase-interacting protein 1 (AKIP-1), is not fully understood. Recently, we reported that full-length, but not C-terminally truncated, BCA3 is incorporated into virions of Mason-Pfizer monkey virus, and that BCA3 enhances HIV-1 protease-induced apoptosis. In the present study, we report that BCA3 is associated with purified and subtilisin-treated HIV particles. Using a combination of immune-based methods and confocal microscopy, we show that the C-terminus of BCA3 is required for packaging into HIV-1 particles. However, we were unable to identify an HIV-1 binding domain for BCA3, and we did not observe any effect of incorporated BCA3 on HIV-1 infectivity. Interestingly, the BCA3 C-terminus was previously identified as a binding site for the catalytic subunit of protein kinase A (PKAc), a cellular protein that is specifically packaged into HIV-1 particles. Based on our analysis of PKAc–BCA3 interactions, we suggest that BCA3 incorporation into HIV-1 particles is mediated by its ability to interact with PKAc.

miRNA-1246 induces pro-inflammatory responses in mesenchymal stem/stromal cells by regulating PKA and PP2A

The tumor microenvironment (TME) has an impact on breast cancer progression by creating a pro-inflammatory milieu within the tumor. However, little is known about the roles of miRNAs in cells of the TME during this process. We identified six putative oncomiRs in a breast cancer dataset, all strongly correlating with poor overall patient survival. Out of the six candidates, miR-1246 was upregulated in aggressive breast cancer subtypes and expressed at highest levels in mesenchymal stem/stroma cells (MSCs). Functionally, miR-1246 led to a p65-dependent increase in transcription and release of pro-inflammatory mediators IL-6, CCL2 and CCL5 in MSCs, and increased NF-κB activity. The pro-inflammatory phenotype of miR-1246 in MSCs was independent of TNFα stimulations and mediated by direct targeting of the tumor-suppressors PRKAR1A and PPP2CB. In vitro recapitulation of the TME revealed increased Stat3 phosphorylation in breast epithelial (MCF10A) and cancer cells (SK-BR-3, MCF7, T47D) upon incubation with conditioned medium (CM) of MSCs overexpressing miR-1246. Additionally, this stimulation enhanced proliferation of MCF10A cells, increased migration of MDA-MB-231 cells and induced attraction of THP-1 monocytic cells. Our data shows that miR-1246 acts as both key-enhancer of pro-inflammatory responses in MSCs and putative oncomiR in breast cancer, suggesting its influence on cancer-related inflammation and breast cancer progression.

AKIP1 promotes angiogenesis and tumor growth by upregulating CXC-chemokines in cervical cancer cells

Upregulation of A-kinase-interacting protein 1 (AKIP1) has been observed in breast and esophageal cancers, indicating that AKIP1 may be a potent oncogenic protein. However, the role of AKIP1 in cervical cancer still remains unknown. This study aimed to explore the role of AKIP1 in cervical cancer and to investigate the underlying mechanism of AKIP1 in tumor growth. Expression of AKIP1 in cervical cancer cells was determined by qRT-PCR and western blotting. Cell-Light EdU and colony formation assays were used to determine cell proliferation. CXCL1 and CXCL8 proteins were quantified by ELISA kits. Western blotting and qRT-PCR were used to examine the alterations in signaling-related proteins and mRNA, respectively. Endothelial cell tube formation assay was performed to evaluate the effect of AKIP1 on angiogenesis. A BALB/c nude mouse xenograft model was used to evaluate the role of AKIP1 in vivo. Cancer cell proliferation was inhibited and tumor growth and angiogenesis restrained in BALB/c nude mice by suppressing AKIP1 expression in cervical cancer cell lines. In addition, overexpression of AKIP1 in cervical cancer cells elevated the levels of CXCL1, CXCL2, and CXCL8. These three chemokines were not only involved in endothelial tube formation by binding to the endothelial receptor CXCR2, but also in cervical cancer cell proliferation and clone formation, which were induced by overexpression of AKIP1. Furthermore, we found that AKIP1-induced chemokine expression was decreased by an inhibitor of nuclear factor kappa-B kinase subunit β. These results show that AKIP1 is crucial in cervical cancer angiogenesis and growth by elevating the levels of the NF-κB-dependent chemokines CXCL1, CXCL2, and CXCL8.

A hemolytic-uremic syndrome-associated strain O113:H21 Shiga toxin-producing Escherichia coli specifically expresses a transcriptional module containing dicA and is related to gene network dysregulation in Caco-2 cells

Shiga toxin-producing (Stx) Escherichia coli (STEC) O113:H21 strains are associated with human diarrhea and some of these strains may cause hemolytic uremic syndrome (HUS). The molecular mechanism underlying this capacity and the differential host cell response to HUS-causing strains are not yet completely understood. In Brazil O113:H21 strains are commonly found in cattle but, so far, were not isolated from HUS patients. Here we conducted comparative gene co-expression network (GCN) analyses of two O113:H21 STEC strains: EH41, reference strain, isolated from HUS patient in Australia, and Ec472/01, isolated from cattle feces in Brazil. These strains were cultured in fresh or in Caco-2 cell conditioned media. GCN analyses were also accomplished for cultured Caco-2 cells exposed to EH41 or Ec472/01. Differential transcriptome profiles for EH41 and Ec472/01 were not significantly changed by exposure to fresh or Caco-2 conditioned media. Conversely, global gene expression comparison of both strains cultured in conditioned medium revealed a gene set exclusively expressed in EH41, which includes the dicA putative virulence factor regulator. Network analysis showed that this set of genes constitutes an EH41 specific transcriptional module. PCR analysis in Ec472/01 and in other 10 Brazilian cattle-isolated STEC strains revealed absence of dicA in all these strains. The GCNs of Caco-2 cells exposed to EH41 or to Ec472/01 presented a major transcriptional module containing many hubs related to inflammatory response that was not found in the GCN of control cells. Moreover, EH41 seems to cause gene network dysregulation in Caco-2 as evidenced by the large number of genes with high positive and negative covariance interactions. EH41 grows slowly than Ec472/01 when cultured in Caco-2 conditioned medium and fitness-related genes are hypoexpressed in that strain. Therefore, EH41 virulence may be derived from its capacity for dysregulating enterocyte genome functioning and its enhanced enteric survival due to slow growth.

AKIP1 promoted epithelial-mesenchymal transition of non-small-cell lung cancer via transactivating ZEB1

Non-small-cell lung cancer (NSCLC) is one of the leading death-related malignancies worldwide with elusive molecular mechanisms. A-kinase interacting protein 1 (AKIP1) is an important regulator controlling metastasis, lymphangiogenesis and angiogenesis. However, the role of AKIP1 in NSCLC progression is still little known. Here, we found that AKIP1 was overexpressed in NSCLC specimens as well as cell lines. Overexpression of AKIP1 in NSLCC tissues was positively correlated with TNM stage, lymph node metastasis and poor prognosis. Knockdown of AKIP1 inhibited NSCLC cell migration, invasion and epithelial-mesenchymal transition (EMT), as indicated by the up-regulation of mesenchymal markers (fibronectin and vimentin) and down-regulation of epithelial marker E-cadherin, whereas overexpression of AKIP1 showed the opposite effects. Moreover, AKIP1 transactivated Zinc Finger E-Box Binding Homeobox 1 (ZEB1) expression via directly binding to ZEB1 promoter, thereby leading to E-cadherin transcriptional repression. Additionally, we observed that the binding efficiency of AKIP1 within ZEB1 promotor was determined by the interaction between AKIP1 and SP1. In conclusion, AKIP1 promoted EMT of NSCLC via transactivating ZEB1, suggesting AKIP1 as a potential therapeutic target.

Breast cancer-associated gene 3 interacts with Rac1 and augments NF-κB signaling in vitro, but has no effect on RANKL-induced bone resorption in vivo

Breast cancer-associated gene 3 (BCA3) is a recently identified adaptor protein whose functions are still being defined. BCA3 has been reported to be an important regulator of nuclear factor-κB (NF-κB) signaling. It has also been reported to interact with the small GTPase, Rac1. Consistent with that observation, in the present study, BCA3 was found to interact with nuclear Rac1 in 293 cells and influence NF-κB signaling. Additional experiments revealed that depending on cell type, BCA3 augmented, attenuated or had no effect on NF-κB signaling in vitro. Since canonical NF-κB signaling is a critical downstream target from activated receptor activator of nuclear factor κB (RANK) that is required for mature osteoclast formation and function, BCA3 was selectively overexpressed in osteoclasts in vivo using the cathepsin K promoter and the response to exogenous receptor activator of nuclear factor κB ligand (RANKL) administration was examined. Despite its ability to augment NF-κB signaling in other cells, transgenic animals injected with high-dose RANKL had the same hypercalcemic response as their wild-type littermates. Furthermore, the degree of bone loss induced by a 2-week infusion of low-dose RANKL was the same in both groups. Combined with earlier studies, the data from our study data indicate that BCA3 can affect NF-κB signaling and that BCA3 plays a cell-type dependent role in this process. The significance of the BCA3/NF-κB interaction in vivo in bone remains to be determined.

Checks and balances: The glucocorticoid receptor and NFĸB in good times and bad

Mutual regulation and balance between the endocrine and immune systems facilitate an organism's stress response and are impaired following chronic stress or prolonged immune activation. Concurrent alterations in stress physiology and immunity are increasingly recognized as contributing factors to several stress-linked neuropsychiatric disorders including depression, anxiety, and post-traumatic stress disorder. Accumulating evidence suggests that impaired balance and crosstalk between the glucocorticoid receptor (GR) and nuclear factor kappa-light-chain-enhancer of activated B cells (NFκB) - effectors of the stress and immune axes, respectively - may play a key role in mediating the harmful effects of chronic stress on mood and behavior. Here, we first review the molecular mechanisms of GR and NFκB interactions in health, then describe potential shifts in the GR-NFκB dynamics in chronic stress conditions within the context of brain circuitry relevant to neuropsychiatric diseases. Furthermore, we discuss developmental influences and sex differences in the regulation of these two transcription factors.

The many faces of compartmentalized PKA signalosomes

Cellular signal transmission requires the dynamic formation of spatiotemporally controlled molecular interactions. At the cell surface information is received by receptor complexes and relayed through intracellular signaling platforms which organize the actions of functionally interacting signaling enzymes and substrates. The list of hormone or neurotransmitter pathways that utilize the ubiquitous cAMP-sensing protein kinase A (PKA) system is expansive. This requires that the specificity, duration, and intensity of PKA responses are spatially and temporally restricted. Hereby, scaffolding proteins take the center stage for ensuring proper signal transmission. They unite second messenger sensors, activators, effectors, and kinase substrates within cellular micro-domains to precisely control and route signal propagation. A-kinase anchoring proteins (AKAPs) organize such subcellular signalosomes by tethering the PKA holoenzyme to distinct cell compartments. AKAPs differ in their modular organization showing pathway specific arrangements of interaction motifs or domains. This enables the cell- and compartment- guided assembly of signalosomes with unique enzyme composition and function. The AKAP-mediated clustering of cAMP and other second messenger sensing and interacting signaling components along with functional successive enzymes facilitates the rapid and precise dissemination of incoming signals. This review article delineates examples for different means of PKA regulation and for snapshots of compartmentalized PKA signalosomes.

Overexpression of AKIP1 predicts poor prognosis of patients with breast carcinoma and promotes cancer metastasis through Akt/GSK-3β/Snail pathway

Recent evidence has demonstrated that A kinase interacting protein 1 (AKIP1), a molecular regulator of protein kinase A, was overexpressed in breast cancer. However, the prognostic and biological role of AKIP1 in breast cancer is still elusive. The purpose of our study was to elucidate the role and molecular mechanism of AKIP1 in breast cancer development. The mRNA levels of AKIP1 in breast cancer and paired normal breast tissues were examined by quantitative real-time PCR. The relationship of AKIP1 expression with clinicopathological characteristics and clinical prognosis of breast cancer patients was investigated. In vitro migration and invasion assays were performed in MCF-7 and SK-BR-3 cells to determine its role in metastasis and the possible mechanism. The result showed that AKIP1 expression was up-regulated in breast cancer tissues compared with that in normal breast tissues. High expression of AKIP1 was associated significantly with advanced tumor stage (P<0.001), tumor size (P=0.029), and lymph node metastasis (P=0.004). Moreover, overexpression of AKIP1 was significantly correlated with poor overall survival and recurrence-free survival (P=0.038 and P=0.005, respectively). Furthermore, down-regulation of AKIP1 remarkably inhibited breast cancer cell motility and invasion through inhibiting the Akt/GSK-3β/Snail pathway. Therefore, AKIP1 may represent a prospective prognostic indicator and a potential therapeutic target of breast cancer.

Simulation of the effects of moderate stimulation/inhibition of the β1-adrenergic signaling system and its components in mouse ventricular myocytes

The β1-adrenergic signaling system is one of the most important protein signaling systems in cardiac cells. It regulates cardiac action potential duration, intracellular Ca2+concentration ([Ca2+]i) transients, and contraction force. In this paper, a comprehensive experimentally based mathematical model of the β1-adrenergic signaling system for mouse ventricular myocytes is explored to simulate the effects of moderate stimulations of β1-adrenergic receptors (β1-ARs) on the action potential, Ca2+and Na+dynamics, as well as the effects of inhibition of protein kinase A (PKA) and phosphodiesterase of type 4 (PDE4). Simulation results show that the action potential prolongations reach saturating values at relatively small concentrations of isoproterenol (∼0.01 μM), while the [Ca2+]itransient amplitude saturates at significantly larger concentrations (∼0.1–1.0 μM). The differences in the response of Ca2+and Na+fluxes to moderate stimulation of β1-ARs are also observed. Sensitivity analysis of the mathematical model is performed and the model limitations are discussed. The investigated model reproduces most of the experimentally observed effects of moderate stimulation of β1-ARs, PKA, and PDE4 inhibition on the L-type Ca2+current, [Ca2+]itransients, and the sarcoplasmic reticulum Ca2+load and makes testable predictions for the action potential duration and [Ca2+]itransients as functions of isoproterenol concentration.

The Regulation of NF-κB Subunits by Phosphorylation

The NF-κB transcription factor is the master regulator of the inflammatory response and is essential for the homeostasis of the immune system. NF-κB regulates the transcription of genes that control inflammation, immune cell development, cell cycle, proliferation, and cell death. The fundamental role that NF-κB plays in key physiological processes makes it an important factor in determining health and disease. The importance of NF-κB in tissue homeostasis and immunity has frustrated therapeutic approaches aimed at inhibiting NF-κB activation. However, significant research efforts have revealed the crucial contribution of NF-κB phosphorylation to controlling NF-κB directed transactivation. Importantly, NF-κB phosphorylation controls transcription in a gene-specific manner, offering new opportunities to selectively target NF-κB for therapeutic benefit. This review will focus on the phosphorylation of the NF-κB subunits and the impact on NF-κB function.

Elevated TAK1 augments tumor growth and metastatic capacities of ovarian cancer cells through activation of NF-κB signaling

Transforming growth factor (TGF)-β-activating kinase 1 (TAK1) is a serine/threonine kinase which is frequently associated with human cancer progression. However, its functional role in tumorigenesis is still controversial. Here, we report that TAK1 enhances the oncogenic capacity of ovarian cancer cells through the activation of NF-κB signaling. We found that TAK1 is frequently upregulated and significantly associated with high-grade and metastatic ovarian cancers. Mechanistic studies showed that Ser412 phosphorylation is required for TAK1 in activating NF-κB signaling and promotes aggressiveness of ovarian cancer cells. Conversely, suppression of TAK1 activity by point mutation at Ser412, RNAi mediated gene knockdown or TAK1 specific inhibitor ((5Z) -7-Oxozeaenol) remarkably impairs tumor growth and metastasis in ovarian cancer in vitro and in vivo. Our study underscores the importance of targeting TAK1 as a promising therapeutic approach to counteract the ovarian cancer progression.

Cross-talk between PKA-Cβ and p65 mediates synergistic induction of PDE4B by roflumilast and NTHi

Phosphodiesterase 4B (PDE4B) plays a key role in regulating inflammation. Roflumilast, a phosphodiesterase (PDE)4-selective inhibitor, has recently been approved for treating severe chronic obstructive pulmonary disease (COPD) patients with exacerbation. However, there is also clinical evidence suggesting the development of tachyphylaxis or tolerance on repeated dosing of roflumilast and the possible contribution of PDE4B up-regulation, which could be counterproductive for suppressing inflammation. Thus, understanding how PDE4B is up-regulated in the context of the complex pathogenesis and medications of COPD may help improve the efficacy and possibly ameliorate the tolerance of roflumilast. Here we show that roflumilast synergizes with nontypeable Haemophilus influenzae (NTHi), a major bacterial cause of COPD exacerbation, to up-regulate PDE4B2 expression in human airway epithelial cells in vitro and in vivo. Up-regulated PDE4B2 contributes to the induction of certain important chemokines in both enzymatic activity-dependent and activity-independent manners. We also found that protein kinase A catalytic subunit β (PKA-Cβ) and nuclear factor-κB (NF-κB) p65 subunit were required for the synergistic induction of PDE4B2. PKA-Cβ phosphorylates p65 in a cAMP-dependent manner. Moreover, Ser276 of p65 is critical for mediating the PKA-Cβ-induced p65 phosphorylation and the synergistic induction of PDE4B2. Collectively, our data unveil a previously unidentified mechanism underlying synergistic up-regulation of PDE4B2 via a cross-talk between PKA-Cβ and p65 and may help develop new therapeutic strategies to improve the efficacy of PDE4 inhibitor.

β2-Adrenergic receptors in immunity and inflammation: stressing NF-κB

β2-Adrenergic receptors (β2-ARs) transduce the effects of (nor)epinephrine on a variety of cell types and act as key mediators of the body's reaction to stress. β2-ARs are also expressed on immune cells and there is ample evidence for their role in immunomodulation. A key regulator of the immune response and a target for regulation by stress-induced signals is the transcription factor Nuclear Factor-kappaB (NF-κB). NF-κB shapes the course of both innate and adaptive immune responses and plays an important role in susceptibility to disease. In this review, we summarise the literature that has been accumulated in the past 20years on adrenergic modulation of NF-κB function. We here focus on the molecular basis of the reported interactions and show that both physiological and pharmacological triggers of β2-ARs intersect with the NF-κB signalling cascade at different levels. Importantly, the action of β2-AR-derived signals on NF-κB activity appears to be highly cell type specific and gene selective, providing opportunities for the development of selective NF-κB modulators.

Structural insights into mis-regulation of protein kinase A in human tumors

The extensively studied cAMP-dependent protein kinase A (PKA) is involved in the regulation of critical cell processes, including metabolism, gene expression, and cell proliferation; consequentially, mis-regulation of PKA signaling is implicated in tumorigenesis. Recent genomic studies have identified recurrent mutations in the catalytic subunit of PKA in tumors associated with Cushing's syndrome, a kidney disorder leading to excessive cortisol production, and also in tumors associated with fibrolamellar hepatocellular carcinoma (FL-HCC), a rare liver cancer. Expression of a L205R point mutant and a DnaJ-PKA fusion protein were found to be linked to Cushing's syndrome and FL-HCC, respectively. Here we reveal contrasting mechanisms for increased PKA signaling at the molecular level through structural determination and biochemical characterization of the aberrant enzymes. In the Cushing's syndrome disorder, we find that the L205R mutation abolishes regulatory-subunit binding, leading to constitutive, cAMP-independent signaling. In FL-HCC, the DnaJ-PKA chimera remains under regulatory subunit control; however, its overexpression from the DnaJ promoter leads to enhanced cAMP-dependent signaling. Our findings provide a structural understanding of the two distinct disease mechanisms and they offer a basis for designing effective drugs for their treatment.

A-kinase anchoring proteins: cAMP compartmentalization in neurodegenerative and obstructive pulmonary diseases

The universal second messenger cAMP is generated upon stimulation of Gs protein-coupled receptors, such as the β2 -adreneoceptor, and leads to the activation of PKA, the major cAMP effector protein. PKA oscillates between an on and off state and thereby regulates a plethora of distinct biological responses. The broad activation pattern of PKA and its contribution to several distinct cellular functions lead to the introduction of the concept of compartmentalization of cAMP. A-kinase anchoring proteins (AKAPs) are of central importance due to their unique ability to directly and/or indirectly interact with proteins that either determine the cellular content of cAMP, such as β2 -adrenoceptors, ACs and PDEs, or are regulated by cAMP such as the exchange protein directly activated by cAMP. We report on lessons learned from neurons indicating that maintenance of cAMP compartmentalization by AKAP5 is linked to neurotransmission, learning and memory. Disturbance of cAMP compartments seem to be linked to neurodegenerative disease including Alzheimer's disease. We translate this knowledge to compartmentalized cAMP signalling in the lung. Next to AKAP5, we focus here on AKAP12 and Ezrin (AKAP78). These topics will be highlighted in the context of the development of novel pharmacological interventions to tackle AKAP-dependent compartmentalization.

Comparison of the effects of PRKAR1A and PRKAR2B depletion on signaling pathways, cell growth, and cell cycle control of adrenocortical cells

The cyclic AMP/protein kinase A signaling cascade is one of the main pathways involved in the pathogenesis of adrenocortical tumors. The PKA R1A and R2B proteins are the most abundant regulatory subunits in endocrine tissues. Inactivating mutations of PRKAR1A are associated with Carney complex and a subset of sporadic tumors and the abundance of R2B protein is low in a subset of secreting adrenocortical adenomas. We previously showed that PRKAR1A and PRKAR2B inactivation have anti-apoptotic effects on the adrenocortical carcinoma cell line H295R. The aim of this study was to compare the effects of PRKAR1A and PRKAR2B depletion on cell proliferation, apoptosis, cell signaling pathways, and cell cycle regulation. We found that PRKAR2B depletion is compensated by an upregulation of R1A protein, whereas PRKAR1A depletion has no effect on the production of R2B. The depletion of either PRKAR1A or PRKAR2B promotes the expression of Bcl-xL and resistance to apoptosis; and is associated with a high percentage of cells in S and G2 phase, activates PKA and MEK/ERK pathways, and impairs the expression of IkB leading to activate the NF-κB pathway. However, we observed differences in the regulation of cyclins. The depletion of PRKAR1A leads to the accumulation of cyclin D1 and p27kip, whereas the depletion of PRKAR2B promotes the accumulation of cyclin A, B, cdk1, cdc2, and p21Cip. In conclusion, although the depletion of PRKAR1A and PRKAR2B in adrenocortical cells has similar effects on cell proliferation and apoptosis; loss of these PKA subunits differentially affects cyclin expression.