AKAP12 Expression Research Articles

Identifying genes for regulating osteogenic differentiation of human periodontal ligament stem cells in inflammatory environments by bioinformatics analysis.

Periodontitis is an immuno-inflammatory disease caused by dental plaque biofilms and inflammations. The regeneration of bone tissue in inflammatory environment is of great significance for the treatment of periodontal disease, but the specific molecular mechanism of bone formation in periodontitis still needs further exploration. The objective of this study was to identify key osteogenesis-related genes (ORGs) in periodontitis. We used two datasets from the Gene Expression Omnibus (GEO) database to find differentially expressed mRNAs and miRNAs, further performed Gene Ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis. Then we predicted the downstream genes of the differentially expressed miRNAs (DEMs) by the TargetScan database and established a miRNA-mRNA regulatory network. Finally, the osteogenic mechanism of periodontitis was explored through quantitative real-time PCR (qRT-PCR) by inducing inflammatory environment and osteogenic differentiation of hPDLSCs. Through differential expression analysis and prediction of downstream target genes of DEMs, we created a miRNA-mRNA regulatory network consisting of 29 DEMs and 11 differentially expressed osteogenesis-related genes (DEORGs). In addition, the qRT-PCR results demonstrated that BTBD3, PLAT, AKAP12, SGK1, and GLCE expression levels were significantly upregulated, while those of TIMP3, ZCCHC14, LIN7A, DNAH6, NNT, and ITGA6 were downregulated under the dual effects of inflammatory stimulation and osteogenic induction. DEORGs might be important factors in the osteogenic phase of periodontitis, and the miRNA-mRNA network may shed light on the clarification of the role and mechanism of osteogenesis in periodontitis and contribute to the development of novel therapeutic strategies.

AKAP12 promotes cancer stem cell-like phenotypes and activates STAT3 in colorectal cancer.

Cancer stem cells (CSCs) have unique biological characteristics, including tumorigenicity, immortality, and chemoresistance. Colorectal CSCs have been identified and isolated from colorectal cancers by various methods. AKAP12, a scaffolding protein, is considered to act as a potential suppressor in colorectal cancer, but its role in CSCs remains unknown. In this study, we investigated the function of AKAP12 in Colorectal CSCs. Herein, Colorectal CSCs were enriched by cell culture with a serum-free medium. CSC-associated characteristics were evaluated by Flow cytometry assay and qPCR. AKAP12 gene expression was regulated by lentiviral transfection assay. The tumorigenicity of AKAP12 in vivo by constructing a tumor xenograft model. The related pathways were explored by qPCR and Western blot. The depletion of AKAP12 reduced colony formation, sphere formation, and expression of stem cell markers in colorectal cancer cells, while its knockdown decreased the volume and weight of tumor xenografts in vivo. AKAP12 expression levels also affected the expression of stemness markers associated with STAT3, potentially via regulating the expression of protein kinase C. This study suggests Colorectal CSCs overexpress AKAP12 and maintain stem cell characteristics through the AKAP12/PKC/STAT3 pathway. AKAP12 may be an important therapeutic target for blocking the development of colorectal cancer in the field of cancer stem cells.

Role of A-Kinase Anchoring Protein 12 in the Central Nervous System.

A-kinase anchoring protein (AKAP) 12 is a scaffolding protein that anchors various signaling proteins to the plasma membrane. These signaling proteins include protein kinase A, protein kinase C, protein phosphatase 2B, Src-family kinases, cyclins, and calmodulin, which regulate their respective signaling pathways. AKAP12 expression is observed in the neurons, astrocytes, endothelial cells, pericytes, and oligodendrocytes of the central nervous system (CNS). Its physiological roles include promoting the development of the blood-brain barrier, maintaining white-matter homeostasis, and even regulating complex cognitive functions such as long-term memory formation. Under pathological conditions, dysregulation of AKAP12 expression levels may be involved in the pathology of neurological diseases such as ischemic brain injury and Alzheimer's disease. This minireview aimed to summarize the current literature on the role of AKAP12 in the CNS.

Review of Notch signaling regulates Akap12 expression and primary cilia length during renal tubule morphogenesis

Review of Notch signaling regulates Akap12 expression and primary cilia length during renal tubule morphogenesis

Physiologic and pathophysiologic roles of AKAP12.

A kinase anchoring protein (AKAP) 12 is a scaffolding protein that improves the specificity and efficiency of spatiotemporal signal through assembling intracellular signal proteins into a specific complex. AKAP12 is a negative mitogenic regulator that plays an important role in controlling cytoskeletal architecture, maintaining endothelial integrity, regulating glial function and forming blood-brain barrier (BBB) and blood retinal barrier (BRB). Moreover, elevated or reduced AKAP12 contributes to a variety of diseases. Complex connections between AKAP12 and various diseases including chronic liver diseases (CLDs), inflammatory diseases and a series of cancers will be tried to delineate in this paper. We first describe the expression, distribution and physiological function of AKAP12. Then we summarize the current knowledge of different connections between AKAP12 expression and various diseases. Some research groups have found paradoxical roles of AKAP12 in different diseases and further confirmation is needed. This paper aims to assess the role of AKAP12 in physiology and diseases to help lay the foundation for the design of small molecules for specific AKAP12 to correct the pathological signal defects.

AKAP12 Modulates β‐arrestin2 Recruitment to the β2‐Adrenergic Receptors

BackgroundG‐Protein Coupled Receptors (GPCRs) are central mediators of signaling cascades in many biological systems. GPCRs internalization rates vary based on the presence/absence of its ligand and the type of the receptor. β2‐Adrenergic Receptor (β2AR) is a prototypical GPCR, reaching its maximum in internalization within ~10 minutes after ligand treatment. One regulator of β2AR internalization is β‐arrestin2. GPCR–β‐arrestin binding is biphasic where the phosphorylated carboxyl terminus of GPCRs docks to the N‐domain of β‐arrestin first, and then the seven transmembrane core of the receptor engages with β‐arrestin. However, it has been discovered that the core interaction is dispensable for receptor endocytosis. AKAP12 is a large scaffolding protein that was reported to be essential in agonist‐induced internalization and resensitization of β2AR. Our central hypothesis is that higher expression levels of AKAP12 may enhance β‐arrestin2 recruitment to the β2AR and subsequently increase β2AR internalization.MethodsHEK293 cells were grouped into three groups: [1] Controls: endogenous AKAP12 expression, [2] Overexpression (OX): transiently overexpressing human AKAP12, and [3] Knockdown (KD): treated with human AKAP12 siRNA. β‐arrestin2 recruitment to the receptor and β2AR internalization was evaluated using the Nanobit luciferase system. For each assay, we tested four β2AR‐β‐arrestin2 or Early Endosome‐β2AR orientations. Orientation pairs with the highest luminescence signals were used for the experiments to obtain maximum sensitivity. At 48 hours post‐transfection, Nanobit assays were performed by recording baseline luminescence for 10 minutes. Next, 10µM epinephrine was added and luminescence measurements were recorded immediately and then once every minute for 1 hour. Results are represented as Luminescence Fold Induction (LFI). Receptor trafficking to early endosomes post epinephrine treatment was further confirmed using the Proximity Ligation Assay (PLA).ResultsHEK cells, OX AKAP12 [9 fold higher] had a significantly lower β‐arrestin2 recruitment to the β2AR (2.26±0.39, LFI) as compared to controls (7.47±1.12, LFI; p=0.0004). AKAP12 KD [AKAP12 ~80% silenced] had a significantly higher β‐arrestin2 recruitment to the β2AR (10.35±0.56, LFI) as compared to both control and OX AKAP12 groups (p=0.035 and p<0.0001), respectively. At 15 minutes post epinephrine addition, β2AR trafficking to early endosomes was significantly lower in the OX AKAP12 group (1.82±0.22, LFI), as compared to the control (2.47±0.09, LFI; p=0.01), while the KD AKAP12 group had a significantly higher internalization (2.98±0.14, LFI), as compared to control and OX AKAP12 groups (p=0.005 and p=0.0003), respectively. Our PLA data further confirmed that the OX AKAP12 group displayed significantly lower β2AR trafficking as defined by its decreased interaction with Early Endosome Antigen 1 (EEA1), as compared to the control (p= 0.0451).ConclusionsContrary to previously thought, higher AKAP12 expression levels may interfere with β2AR trafficking to early endosomes partially through inhibiting β‐arrestin2 recruitment to the β2AR.

Mechanisms of PALLD, PRKCH, AKAP12, PDK4, and CHIT1 Proteins in Serum Diagnosis of Neonatal Sepsis.

The mechanism of PALLD, PRKCH, AKAP12, PDK4, and CHIT1 proteins in serum diagnosis of neonatal sepsis (NS) was explored. Analysis of PALLD, PRKCH, AKAP12, PDK4, and CHIT1 expression in serum from NS patients and their correlations were manifested. Evaluation of the ability of PALLD, PRKCH, AKAP12, PDK4, and CHIT1 to identify NS was manifested. Analysis of the prognostic value of PALLD, PRKCH, AKAP12, PDK4, and CHIT1 was in NS. Elevated PALLD, PRKCH, AKAP12, PDK4, and CHIT1 were found in serum from NS patients. Serum PALLD, PRKCH, AKAP12, PDK4, and CHIT1 have diagnostic value for NS. Moreover, PALLD could predict the overall survival of NS patients. This study clarifies elevated PALLD, PRKCH, AKAP12, PDK4, and CHIT1 in NS patients. Meanwhile, PALLD, PRKCH, AKAP12, PDK4, and CHIT1 are available to offer brand-new non-invasive biomarkers for NS's prognosis and diagnosis.

MiR-338-3p improved lung adenocarcinoma by AKAP12 suppression.

IntroductionThis study aimed to explore the biological functions of AKAP12 in lung adenocarcinoma and investigate the interaction between AKAP12 and miR-338-3p.Material and methodsSixty-one differentially expressed genes in lung adenocarcinoma and adjacent normal tissues were first analyzed by TCGA. Immunohistochemistry and quantitative reverse transcription PCR (qRT-PCR) were further utilized to confirm aberrant AKAP12 expression in tumor tissues. The influences of AKAP12 on proliferation, invasion and migration, and apoptosis of lung adenocarcinoma were investigated by clone formation assay and MTT assay, transwell assay, and flow cytometry analysis respectively. TargetScan and miRanda databases predicted the binding sites of miRNAs on AKAP12 3′-UTR and structure changes were validated by RNA folding form. The target relationship between miR-338-3p and AKAP12 was confirmed by the dual-luciferase reporter system. Disease-free survival (DFS) and overall survival (OS) curves were generated with Kaplan-Meier plotter according to the TCGA data and the correlation among AKAP12 expression, miR-338-3p expression and prognosis was also analyzed.ResultsAKAP12 was upregulated in lung adenocarcinoma tissues and cells (all p < 0.01), and negatively correlated with prognosis outcomes of patients (both p < 0.05). High expression of AKAP12 promoted proliferation, invasion and migration of cancer cells, and inhibited cell apoptosis (all p < 0.05). MiR-338-3p could directly bind to the 3′-UTR of AKAP12 and showed most significant suppression on AKAP12 expression among four predicted miRNAs (all p < 0.01). Additionally, miR-338-3p could suppress AKAP12 in lung adenocarcinoma, improving prognosis (all p < 0.05).ConclusionsAKAP12 acts as a tumor promoter in lung adenocarcinoma development. Upregulation of MiR-338-3p could suppress AKAP12 expression in lung cancer cells and contribute to a better prognosis.

Roles of A-kinase Anchor Protein 12 in Astrocyte and Oligodendrocyte Precursor Cell in Postnatal Corpus Callosum.

The formation of the corpus callosum in the postnatal period is crucial for normal neurological function, and clinical genetic studies have identified an association of 6q24-25 microdeletion in this process. However, the mechanisms underlying corpus callosum formation and its critical gene(s) are not fully understood or identified. In this study, we examined the roles of AKAP12 in postnatal corpus callosum formation by focusing on the development of glial cells, because AKAP12 is coded on 6q25.1 and has recently been shown to play roles in the regulations of glial function. In mice, the levels of AKAP12 expression was confirmed to be larger in the corpus callosum compared to the cortex, and AKAP12 levels decreased with age both in the corpus callosum and cortex regions. In addition, astrocytes expressed AKAP12 in the corpus callosum after birth, but oligodendrocyte precursor cells (OPCs), another major type of glial cell in the developing corpus callosum, did not. Furthermore, compared to wild types, Akap12 knockout mice showed smaller numbers of both astrocytes and OPCs, along with slower development of corpus callosum after birth. These findings suggest that AKAP12 signaling may be required for postnatal glial formation in the corpus callosum through cell- and non-cell autonomous mechanisms.

AKAP12 Expression in HER2-positive Breast Cancer and Its Clinical Significance

AKAP12 Expression in HER2-positive Breast Cancer and Its Clinical Significance

Notch signaling regulates Akap12 expression and primary cilia length during renal tubule morphogenesis.

Alagille syndrome patients present with loss of function mutations in either JAG1 or NOTCH2. About 40%-50% of patients have kidney abnormalities, and frequently display multicystic, dysplastic kidneys. Additionally, gain-of-function mutations in NOTCH2 are associated with cystic kidneys in Hajdu-Cheney syndrome patients. How perturbations in Notch signaling cause renal tubular cysts remains unclear. Here, we have determined that reduced Notch signaling mediated transcription by ectopic expression of dominant-negative mastermind-like (dnMaml) peptide in the nephrogenic epithelia from after the s-shaped body formation and in the developing collecting ducts results in proximal tubular and collecting duct cysts, respectively. An acute inhibition of Notch signaling for two days during kidney development is sufficient to disrupt tubule formation, and significantly increases Akap12 expression. Ectopic expression of Akap12 in renal epithelia results in abnormally long primary cilia similar to that observed in Notch-signaling-deficient epithelia. Both loss of Notch signaling and elevated Akap12 expression disrupt the ability of renal epithelial cells to form spherical structures with a single lumen when grown embedded in matrix. Interestingly, Akap12 can inhibit Notch signaling mediated transcription, which likely explains how both loss of Notch signaling and ectopic expression of Akap12 result in similar renal epithelial abnormalities. We conclude that Notch signaling regulates Akap12 expression while also ensuring normal primary cilia length and renal epithelial morphogenesis, and suggest that one aspect of diseases associated with defective Notch signaling, such as Alagille syndrome, maybe mechanistically related to ciliopathies.

AKAP12 Endogenous Transcripts Suppress The Proliferation, Migration And Invasion Of Colorectal Cancer Cells By Directly Targeting oncomiR-183-5p.

PurposeRestoring lost function to suppressor gene products has captured the interest of the research community in the field of gene therapy. AKAP12, also known as Gravin/AKAP250, is a tumor suppressor gene, and its deregulation may be responsible for cancer progression. The aim of this study was to investigate whether AKAP12 mRNA has an anti-cancer function by regulating onco-miRNA expression in colorectal cancer (CRC) cells.MethodsmiRNAs targeting AKAP12 were predicted by bioinformatics analysis and further confirmed by dual-luciferase reporter assays and RT-qPCR. The altered expression of microRNA was validated in early-stage CRC tumor tissues by miRseq. Cell proliferation was measured by Cell Counting Kit-8 (CCK-8) assay. Cell invasion and migration were detected by transwell and wound healing assays, respectively. In vivo experiments were conducted to confirm the in vitro findings.ResultsAmong all miRNAs, reversed correlation between AKAP12 expression and miRNA-183-5p expression was most significant. Luciferase assays revealed that AKAP12 directly targeted miR-183-5p. The miRseq data showed that miR-183 was also dysregulated at the early stage of tumor development and upregulated in late sub-stage II CRC patients (P<0.01). Mechanistic analysis both in vitro and in vivo demonstrated that anti-miR-183-5p depressed cell proliferation, migration, and invasion in CRC cells while miR-183-5p overexpression resulted in opposite effects.ConclusionOur findings suggested that oncomiR-183-5p promoted the proliferation, migration, and invasion of CRC cells. AKAP12 miRNA-binding elements (MREs) suppressed miRNA-183-5p activities. Any change in expression of AKAP12 thus affected miRNA-183-5p. This may be another anti-tumor mechanism in addition to protein-mediation that regulates tumor suppressor genes.

A-kinase anchoring protein 12 is downregulated in human hepatocellular carcinoma and its deficiency in mice aggravates thioacetamide-induced liver injury.

AKAP12 belongs to A-kinase anchoring protein (AKAP) family of scaffold proteins and is known as a tumor suppressor in several human cancer types. Its role as a tumor suppressor in hepatocellular carcinoma (HCC) was proposed due to its downregulation and epigenetic modification in human HCC; however, the effect of its deficiency on liver injuries, such as liver fibrosis and cancer has been poorly studied. By analyzing tumor and non-tumor tissues of 15 patients with HCC, it was confirmed that AKAP12 expression was downregulated in human HCC as compared with adjacent non-tumor tissues. Immunohistochemical staining of mouse liver tissue for AKAP12 revealed that its sinusoidal expression was diminished in capillarized endothelium after 8 weeks of thioacetamide (TAA) administration. AKAP12 deficiency resulted in the promotion of ductular response of biliary epithelial cells, whereas overall fibrosis and myofibroblast activation were comparable between genotypes after short-term TAA treatment. The mRNA expressions of some fibrosis-related genes such as those encoding epithelial cell adhesion molecule, collagen type 1 α1 and elastin were upregulated in liver tissues of AKAP12-knockout mice. Long-term administration of TAA for 26 weeks led to the development of liver tumors; the incidence of tumor development was higher in AKAP12-deficient mice than in wild-type littermates. Together, these results suggest that AKAP12 functions as a tumor suppressor in liver cancer and is associated with the regulation of hepatic non-parenchymal cells.

Aldosterone Impairs Mitochondrial Function in Human Cardiac Fibroblasts via A-Kinase Anchor Protein 12

Aldosterone (Aldo) contributes to mitochondrial dysfunction and cardiac oxidative stress. Using a proteomic approach, A-kinase anchor protein (AKAP)-12 has been identified as a down-regulated protein by Aldo in human cardiac fibroblasts. We aim to characterize whether AKAP-12 down-regulation could be a deleterious mechanism which induces mitochondrial dysfunction and oxidative stress in cardiac cells. Aldo down-regulated AKAP-12 via its mineralocorticoid receptor, increased oxidative stress and induced mitochondrial dysfunction characterized by decreased mitochondrial-DNA and Peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α) expressions in human cardiac fibroblasts. CRISPR/Cas9-mediated knock-down of AKAP-12 produced similar deleterious effects in human cardiac fibroblasts. CRISPR/Cas9-mediated activation of AKAP-12 blunted Aldo effects on mitochondrial dysfunction and oxidative stress in human cardiac fibroblasts. In Aldo-salt-treated rats, cardiac AKAP-12, mitochondrial-DNA and PGC-1α expressions were decreased and paralleled increased oxidative stress. In myocardial biopsies from patients with aortic stenosis (AS, n = 26), AKAP-12, mitochondrial-DNA and PGC-1α expressions were decreased as compared to Controls (n = 13). Circulating Aldo levels inversely correlated with cardiac AKAP-12. PGC-1α positively associated with AKAP-12 and with mitochondrial-DNA. Aldo decreased AKAP-12 expression, impairing mitochondrial biogenesis and increasing cardiac oxidative stress. AKAP-12 down-regulation triggered by Aldo may represent an important event in the development of mitochondrial dysfunction and cardiac oxidative stress.

Micro-RNA-186-5p inhibition attenuates proliferation, anchorage independent growth and invasion in metastatic prostate cancer cells

BackgroundDysregulation of microRNA (miRNA) expression is associated with hallmarks of aggressive tumor phenotypes, e.g., enhanced cell growth, proliferation, invasion, and anchorage independent growth in prostate cancer (PCa).MethodsSerum-based miRNA profiling involved 15 men diagnosed with non-metastatic (stage I, III) and metastatic (stage IV) PCa and five age-matched disease-free men using miRNA arrays with select targets confirmed by quantitative real-time PCR (qRT-PCR). The effect of miR-186-5p inhibition or ectopic expression on cellular behavior of PCa cells (i.e., PC-3, MDA-PCa-2b, and LNCaP) involved the use bromodeoxyuridine (BrdU) incorporation, invasion, and colony formation assays. Assessment of the impact of miR-186-5p inhibition or overexpression on selected targets entailed microarray analysis, qRT-PCR, and/or western blots. Statistical evaluation used the modified t-test and ANOVA analysis.ResultsMiR-186-5p was upregulated in serum from PCa patients and metastatic PCa cell lines (i.e., PC-3, MDA-PCa-2b, LNCaP) compared to serum from disease-free individuals or a normal prostate epithelial cell line (RWPE1), respectively. Inhibition of miR-186-5p reduced cell proliferation, invasion, and anchorage-independent growth of PC-3 and/or MDA-PCa-2b PCa cells. AKAP12, a tumor suppressor target of miR-186-5p, was upregulated in PC-3 and MDA-PCa-2b cells transfected with a miR-186-5p inhibitor. Conversely, ectopic miR-186-5p expression in HEK 293 T cells decreased AKAP12 expression by 30%. Both pAKT and β-catenin levels were down-regulated in miR-186-5p inhibited PCa cells.ConclusionsOur findings suggest miR-186-5p plays an oncogenic role in PCa. Inhibition of miR-186-5p reduced PCa cell proliferation and invasion as well as increased AKAP12 expression. Future studies should explore whether miR-186-5p may serve as a candidate prognostic indicator and a therapeutic target for the treatment of aggressive prostate cancer.

Suppression of miR‐186 Attenuates Cellular Invasion, pAKT and β‐catenin in Metastatic Prostate Cancer Cell Models

BackgroundMicroRNA (miR) dysregulation alters the expression of cancer related genes and contributes to disease states in many cancers. For example, ectopic miR‐186 expression leads to enhanced cell proliferation and migration in pancreatic cancer. However, the role of miR‐186 in prostate cancer (PCa) remains unclear. Previously, we observed significant upregulation of miR‐186‐5p in PCa patient serum (stage III/IV) and PCa cell lines relative to appropriate controls. Moreover, inhibition of miR‐186 reduced cell proliferation and anchorage‐independent growth of PC‐3 PCa cells. However, the impact of miR‐186 inhibition on cell invasion and its corresponding mechanism is unknown.HypothesisWe speculated miR‐186 inhibition would repress cellular invasion in metastatic PCa cell lines, presumably by up‐regulating tumor suppressor gene(s) involved in at least one hallmark of cancer.MethodsAssessment of the impact of miR‐186 inhibition or overexpression on selected targets entailed microarray analysis, qRT‐PCR, and/or western blots. Candidate miR‐186 targets were selected using published reports on ‘miR‐186 and cancer’, availability of robust antibodies, and statistical filtering (false discovery ≥0.05 and ±1.2 fold change). Statistical evaluation used the modified t‐test, and ANOVA analysis.ResultsMir‐186 inhibition in PC‐3 cells significantly repressed proliferation and colony formation by 34–64% in PC3 and/or MDA‐PCA‐2b cells. Following miR‐186 inhibition in PC‐3 cells and overexpression in RWPE1 cells, 1,040 identified mRNA targets were differentially expressed compared to scramble controls (p &lt; 0.05). The candidate miR‐186 target gene list focused on 11 up‐regulated candidates. One of the up‐regulated genes, AKAP12, plays a role in cell death, cell migration, cell proliferation, colony formation, and cell invasion. AKAP12 also possessed three miR‐186 binding sites. Notably, AKAP12 was upregulated in PC‐3 and MDA‐PCa‐2b cells transfected with a miR‐186 inhibitor. Conversely, ectopic miR‐186‐5p expression in HEK 293T cells decreased AKAP12 expression by 30%. Both pAKT and β‐catenin were down‐regulated in miR‐186 inhibited PCa cells. Conversely, overexpressing miR‐186‐5p in normal prostate epithelial RWPE1 cells increased pAKT expression by 30%.ConclusionsOur findings suggest miR‐186 plays an oncogenic role in PCa. The reduction in cell invasion in miR‐186 inhibited cell models corresponded with an up‐regulation of AKAP12, which in turn may reduce p‐AKT and β‐catenin. Repression of p‐AKT and β‐catenin favors a less invasive PCa phenotype. Future studies will further elucidate the mechanism by which miR‐186 inhibition suppresses cellular proliferation, migration, and invasion. Such efforts may lead to the identification of novel biomarkers to improve detection and clinical management strategies for aggressive PCa.Support or Funding InformationNational Cancer Institute Grant R25‐CA‐134283, Our Highest Potential Endowment in Cancer ResearchThis abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Upregulation of AKAP12 with HDAC3 depletion suppresses the progression and migration of colorectal cancer.

A-kinase anchor protein12 (AKAP12; also known as Gravin) functions as a tumor suppressor in several human primary cancers. However, the potential correlation between histone deacetylase3 (HDAC3) and AKAP12 and the underlying mechanisms remain unclear. Thus, in this study, in an aim to shed light into this matter, the expression levels of HDAC3 and AKAP12 in 96colorectal cancer(CRC) and adjacent non-cancerous tissues, as well as in SW480 cells were examined by immunohistochemical, RT-qPCR and western blot analyses. The effects of HDAC3 and AKAP12 on the proliferation, apoptosis and metastasis of CRC cells were examined by cell counting kit-8(CCK-8) assay, colony formation assays, flow cytometry, cell cycle analysis and Transwell assays. The results revealed that the reduction or loss of AKAP12 expression was detected in 69(71.8%) of the 96tissue specimens, whereas HDAC3 was upregulated in 50(52.1%) of the 96tumor tissue specimens. AKAP12 expression was markedly increased upon treatment with the HDAC3 inhibitors, trichostatinA (TSA) and RGFP966, at both the mRNA and protein level. Mechanistically, the direct binding of HDAC3 within the intron-1 region of AKAP12 was identified to be indispensable for the inhibition of AKAP12 expression. Moreover, the proliferation, colony-forming ability, cell cycle progression and the migration of the CRC cells were found to be promoted in response to AKAP12 silencing or AKAP12/HDAC3 co-silencing, whereas transfection with si-HDAC3 yielded opposite effects. Apart from the elevated expression of the anti-apoptotic protein, Bcl-2, after AKAP12 knockdown, the increased activity of PI3K/AKT signaling was found to be indispensable for AKAP12-mediated colony formation and migration. On the whole, these findings indicate that AKAP12 may be a potential prognostic predictor and therapeutic target for the treatment of CRC in combination with HDAC3.

SSeCKS/AKAP12 induces repulsion between human prostate cancer and microvessel endothelial cells through the activation of Semaphorin 3F

Metastasis remains the primary cause of prostate cancer related death. Cancer cells need to contact endothelial cells and disrupt endothelial junctions to cross the endothelium for invasion and metastasis. The suppression of heterotypic repulsion between cancer and endothelial cells allows cancer cells to invade into the surrounding tissue. Here, we demonstrate that SSeCKS/AKAP12 induced repulsion between human prostate cancer and microvessel endothelial cells, which was mediated by an angiogenesis inhibitor Semaphorin 3F. Moreover, we examined AKAP12 and Semaphorin 3F mRNA expression in 42 prostate cancer and 30 benign prostatic hyperplasia tissue samples, and found that the expression of AKAP12 and Semaphorin 3F mRNA was inversely associated with the degree of aggressiveness of prostate cancer cells and tissues. An ordinal logistic regression analysis indicates that there is a positive association between the expression of AKAP12 and Semaphorin 3F in prostate cancer, suggesting that the activation of Semaphorin 3F by SSeCKS/AKAP12 may be involved in prostate cancer progression and metastasis.

MiR-103 regulates hepatocellular carcinoma growth by targeting AKAP12

AKAP12/Gravin (A kinase anchor protein 12) belongs to the group of A-kinase scaffold proteins and functions as a tumor suppressor in some human primary cancers. While AKAP12 is found consistently downregulated in hepatocellular carcinoma (HCC), its involvement in hepatocarcinogenesis has not been fully elucidated. We identified targeting sites for miR-103 in the 3′-untranslated region (3′-UTR) of AKAP12 by bioinformatic analysis and confirm their function by a luciferase reporter gene assay. We reveal miR-103 expression to be inversely correlated with AKAP12 in HCC tissue samples and show that overexpressed miR-103 promotes cell proliferation and inhibits apoptosis by downregulating AKAP12 expression in HCC cell lines. On the other hand, repression of miR-103 suppresses proliferation and promotes apoptosis in HCC cells by increasing AKAP12. In xenografted HCC tumors, overexpression of AKAP12 suppresses tumor growth whereas overexpression of miR-103 enhances tumor growth while repressing AKAP12. Since the activation of telomerase is crucial for cells to gain immortality and proliferation ability, we investigated whether AKAP12 expression affected telomerase activity in HCC cells. Both AKAP12 overexpression and protein kinase Cα (PKCα) inhibition prevent nuclear translocation and phosphorylation of TERT and reduce telomerase activity in HCC cells. These findings indicate that miR-103 potentially acts as an oncogene in HCC by inhibiting AKAP12 expression and raise the possibility that miR-103 increases telomerase activity by increasing PKCα activity. Thus, miR-103 may represent a new potential diagnostic and therapeutic target for HCC treatment.

Abstract 4631: AKAP12 is elevated in paclitaxel-resistant ovarian cancer cells and correlates with poor ovarian cancer patient survival

Abstract Objective: Although most ovarian cancer patients respond initially to the standard of care involving carboplatinum/paclitaxel-based chemotherapy, the majority will recur with chemotherapeutically resistant disease. Unfortunately, no clinical biomarker(s) for predicting or monitoring chemotherapeutic resistance are available. We sought to identify shed and/or secreted proteins from paclitaxel-resistant human ovarian cancer cells and identify whether any of these correlate with ovarian cancer patient outcome. Methods: A proteomic analysis of secretomes from high grade serous ovarian cancer (HGSOC) cells (OV90) was compared to that from a syngeneic paclitaxel-resistant variant (OV90-TR) and a cancer cell line developed from a chemorefractory HGSOC patient. Associations between the identified candidates and patient outcome were assessed from publicly available transcript expression data (n = 545 ovarian cancer patients) and validated independently (n = 795 ovarian cancer patients). Results: Among the 81 differentially abundant proteins identified (q&amp;lt;0.05) from paclitaxel-sensitive vs -resistant HGSOC cell secretomes, AKAP12 was verified to be elevated at the protein and transcript level in all models of paclitaxel-resistant HGSOC. Further, elevated AKAP12 transcript expression was found to significantly correlate with poor progression-free (Hazard Ratio = 1.487 (± 0.148), p = 0.0085 (± 0.002) and overall (Hazard Ratio = 1.22 (± 0.08), p = 0.009 (± 0.013) survival. Conclusions: These findings suggest that elevation and efflux of AKAP12 is characteristic of paclitaxel-resistant HGSOC cells and that elevated AKAP12 expression correlates with poor ovarian cancer patient survival. Citation Format: Nicholas Bateman, Elizabeth Jaworski, Guisong Wang, Elizabeth Dubil, Charlotte Marcus, Kelly Conrads, Pang-ning Teng, Brian Hood, Chad Hamilton, Larry Maxwell, Kathleen Darcy, Thomas Conrads. AKAP12 is elevated in paclitaxel-resistant ovarian cancer cells and correlates with poor ovarian cancer patient survival. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4631. doi:10.1158/1538-7445.AM2015-4631