Cyclase-associated Protein 2 Research Articles

Evaluation of the relationship between immunohistochemical markers and the prognosis of patients with hepatocellular carcinoma

Aims: This study aimed to evaluate whether prognosis and survival time in patients hepatocellular carcinoma (HCC) were associated with immunohistochemistry results for Heat Shock Protein 70 (HSP70), Glutamine synthetase (GS), Cyclase Associated Protein 2 (CAP2), Enhancer of zeste homolog 2 (EZH2) and B-cell-specific Moloney murine leukemia virus integration site 1 (Bmi-1). Methods: In this retrospective study, the medical records of 50 HCC cases were evaluated. Tissues were stained for the targeted antigens. Immunohistochemical stains were scored for cytoplasmic (HSP70, GS, CAP2) or nuclear (EZH2, Bmi-1) staining patterns under light microscopy. Results: Twenty-nine (58%) of the HCC cases died and the overall survival time was 30±3 (24-37) months. Survival times were similar in terms of age (p=0.262), sex (p=0.707), cause of disease (p=0.655), tumor size (p=0.191) and degree of differentiation (p=0.280). The overall survival of HCC patients with vascular invasion was shorter (p=0.019). The frequency of EZH2 (p=0.025) and Bmi-1 (p=0.004) +/++ was higher in patients with vascular invasion. No correlation was found between overall survival time and HSP70 positivity (p=0.140) and CAP2 positivity (p=0.278); however, survival time was significantly shorter in HCC cases stained (++/+++) with EZH2 (p=0.034), Bmi-1 (p=0.008) and GS (p=0.018). Conclusion: The results of this study showed that GS, EZH2, and Bmi-1 predicted prognosis and survival time in patients with HCC, possible due to relationships with vascular invasion. There is a need for more comprehensive, population-based studies on biomarkers that can be used in prognosis monitoring of HCC cases.

CSF levels of the synaptic marker Cyclase‐associated protein CAP2 in Alzheimer disease across clinical stages

AbstractBackgroundSynaptic dysfunction represent a key event in cognitive decline in Alzheimer disease. There is evidence that Cyclase‐associated protein 2 (CAP2) is involved in synaptic plasticity in AD models but its role in clinical setting has never extensively assessed. Aim of this study was to evaluate CAP2 levels in cerebrospinal fluids of AD and other neurodegenerative diseases and their relationship with amyloid and tau related biomarkers.Methodone‐hundred ten AD patients (prodromal AD n = 70; mild to moderate AD n = 40), 20 Lewy Body Dementia (LBD), 20 frontotemporal dementia (FTD) and 40 healthy controls (HC) were investigated and clinically assessed following a standardized neurological and cognitive behavioral assessment. All subjects underwent CSF analyses for h‐tau, p‐tau and Aß42 (Lumipulse) while CAP2 levels were assessed by using standard ELISA. Between‐groups differences and correlations between CSF biomarkers were evaluated using non‐parametric comparisons and partial correlation analyses adjusted for the effect of age, sex and disease duration.ResultAD patients across severity stages showed higher CAP2 levels compared to controls and non‐AD patients (p = 0.001). CAP2 levels did not correlate with disease severity and were independent of APOE genotype. In AD patients, CAP2 levels showed a positive correlation with t‐tau and p‐tau (p<0.001).ConclusionCSF levels of CAP2 were significantly increased in AD patients and correlated with t‐tau and p‐tau independently of amyloid pathology. Altogether, these findings support the hypothesis that AD is specifically associated with synaptic dysfunction since early stages and that amyloid‐related synaptic changes parallels tau‐related axonal degeneration.

CAP2 promotes gastric cancer metastasis by mediating the interaction between tumor cells and tumor-associated macrophages.

The metastasis of cancer cells is the main cause of death in patients with gastric cancer (GC). Mounting evidence has demonstrated the vital importance of tumor-associated macrophages in promoting tumor invasion and metastasis; however, the interaction between tumor cells and macrophages in GC is largely unknown. In this study, we demonstrated that cyclase-associated protein 2 (CAP2) was upregulated in GC, especially in cases with lymph node metastasis, and was correlated with a poorer prognosis. The transcription factor JUN directly bound to the promoter region of CAP2 and activated CAP2 transcription. The N-terminal domain of CAP2 bound to the WD5 to WD7 domains of receptor for activated C kinase 1 (RACK1) and induced M2 macrophage polarization by activating the SRC/focal adhesion kinase (FAK)/ERK signaling pathway, which resulted in IL-4 and IL-10 secretion. Polarized M2 macrophages induced premetastatic niche formation and promoted GC metastasis by secreting TGFB1, which created a TGFB1/JUN/CAP2 positive-feedback loop to activate CAP2 expression continuously. Furthermore, we identified salvianolic acid B as an inhibitor of CAP2, which effectively inhibited GC cell invasion capabilities by suppressing the SRC/FAK/ERK signaling pathway. Our data suggest that CAP2, a key molecule mediating the interaction between GC cells and tumor-associated macrophages, may be a promising therapeutic target for suppressing tumor metastasis in GC.

An association study of cyclase-associated protein 2 and frailty.

Frailty is a geriatric syndrome that results from multisystem impairment caused by age-associated accumulation of deficits. The frailty index is used to define the level of frailty. Several studies have searched for molecular biomarkers associated with frailty, to meet the needs for personalized care. Cyclase-associated protein 2 (CAP2) is a multifunctional actin-binding protein involved in various physiological and pathological processes, that might reflect frailty's intrinsic complexity. This study aimed to investigate the association between frailty index and circulating CAP2 concentration in 467 community-dwelling older adults (median age: 79; range: 65-92 years) from Milan, Italy. The selected robust regression model showed that circulating CAP2 concentration was not associated with chronological age, as well as sex and education. However, circulating CAP2 concentration was significantly and inversely associated with the frailty index: a 0.1-unit increase in frailty index leads to ~0.5-point mean decrease in CAP2 concentration. Furthermore, mean CAP2 concentration was significantly lower in frail participants (i.e., frailty index ≥0.25) than in non-frail participants. This study shows the association between serum CAP2 concentration and frailty status for the first time, highlighting the potential of CAP2 as a biomarker for age-associated accumulation of deficits.

Analysis of mRNA and Protein Levels of CAP2, DLG1 and ADAM10 Genes in Post-Mortem Brain of Schizophrenia, Parkinson's and Alzheimer's Disease Patients.

Schizophrenia (SCZ) is a mental illness characterized by aberrant synaptic plasticity and connectivity. A large bulk of evidence suggests genetic and functional links between postsynaptic abnormalities and SCZ. Here, we performed quantitative PCR and Western blotting analysis in the dorsolateral prefrontal cortex (DLPFC) and hippocampus of SCZ patients to investigate the mRNA and protein expression of three key spine shapers: the actin-binding protein cyclase-associated protein 2 (CAP2), the sheddase a disintegrin and metalloproteinase 10 (ADAM10), and the synapse-associated protein 97 (SAP97). Our analysis of the SCZ post-mortem brain indicated increased DLG1 mRNA in DLPFC and decreased CAP2 mRNA in the hippocampus of SCZ patients, compared to non-psychiatric control subjects, while the ADAM10 transcript was unaffected. Conversely, no differences in CAP2, SAP97, and ADAM10 protein levels were detected between SCZ and control individuals in both brain regions. To assess whether DLG1 and CAP2 transcript alterations were selective for SCZ, we also measured their expression in the superior frontal gyrus of patients affected by neurodegenerative disorders, like Parkinson’s and Alzheimer’s disease. Interestingly, also in Parkinson’s disease patients, we found a selective reduction of CAP2 mRNA levels relative to controls but unaltered protein levels. Taken together, we reported for the first time altered CAP2 expression in the brain of patients with psychiatric and neurological disorders, thus suggesting that aberrant expression of this gene may contribute to synaptic dysfunction in these neuropathologies.

Redefining actin dynamics of the pointed-end complex in striated muscle.

Striated muscle is intricately designed to provide efficient and powerful muscle contractions. Recently, a long sought-after missing component of the thin filament pointed-end machinery was discovered: cyclase-associated protein 2 (CAP2). CAP2 was identified as a crucial contributor to actin polymerization, striated muscle development, and severe muscle disease when mutated.

Endoplasmic Reticulum Stress Induces CAP2 Expression Promoting Epithelial-Mesenchymal Transition in Liver Cancer Cells.

Cyclase-associated protein 2 (CAP2) has been addressed as a candidate biomarker in various cancer types. Previously, we have shown that CAP2 is expressed during multi-step hepatocarcinogenesis; however, its underlying mechanisms in liver cancer cells are not fully elucidated yet. Here, we demonstrated that endoplasmic reticulum (ER) stress induced CAP2 expression, and which promoted migration and invasion of liver cancer cells. We also found that the ER stress-induced CAP2 expression is mediated through activation of protein kinase C epsilon (PKCε) and the promotor binding of activating transcription factor 2 (ATF2). In addition, we further demonstrated that CAP2 expression promoted epithelial-mesenchymal transition (EMT) through activation of Rac1 and ERK. In conclusion, we suggest that ER stress induces CAP2 expression promoting EMT in liver cancer cells. Our results shed light on the novel functions of CAP2 in the metastatic process of liver cancer cells.

CAP2 is a regulator of actin pointed end dynamics and myofibrillogenesis in cardiac muscle

The precise assembly of actin-based thin filaments is crucial for muscle contraction. Dysregulation of actin dynamics at thin filament pointed ends results in skeletal and cardiac myopathies. Here, we discovered adenylyl cyclase-associated protein 2 (CAP2) as a unique component of thin filament pointed ends in cardiac muscle. CAP2 has critical functions in cardiomyocytes as it depolymerizes and inhibits actin incorporation into thin filaments. Strikingly distinct from other pointed-end proteins, CAP2’s function is not enhanced but inhibited by tropomyosin and it does not directly control thin filament lengths. Furthermore, CAP2 plays an essential role in cardiomyocyte maturation by modulating pre-sarcomeric actin assembly and regulating α-actin composition in mature thin filaments. Identification of CAP2’s multifunctional roles provides missing links in our understanding of how thin filament architecture is regulated in striated muscle and it reveals there are additional factors, beyond Tmod1 and Lmod2, that modulate actin dynamics at thin filament pointed ends.

Cyclase-associated protein 2 (CAP2) controls MRTF-A localization and SRF activity in mouse embryonic fibroblasts

Recent studies identified cyclase-associated proteins (CAPs) as important regulators of actin dynamics that control assembly and disassembly of actin filaments (F-actin). While these studies significantly advanced our knowledge of their molecular functions, the physiological relevance of CAPs largely remained elusive. Gene targeting in mice implicated CAP2 in heart physiology and skeletal muscle development. Heart defects in CAP2 mutant mice were associated with altered activity of serum response factor (SRF), a transcription factor involved in multiple biological processes including heart function, but also skeletal muscle development. By exploiting mouse embryonic fibroblasts (MEFs) from CAP2 mutant mice, we aimed at deciphering the CAP2-dependent mechanism relevant for SRF activity. Reporter assays and mRNA quantification by qPCR revealed reduced SRF-dependent gene expression in mutant MEFs. Reduced SRF activity in CAP2 mutant MEFs was associated with altered actin turnover, a shift in the actin equilibrium towards monomeric actin (G-actin) as well as and reduced nuclear levels of myocardin-related transcription factor A (MRTF-A), a transcriptional SRF coactivator that is shuttled out of the nucleus and, hence, inhibited upon G-actin binding. Moreover, pharmacological actin manipulation with jasplakinolide restored MRTF-A distribution in mutant MEFs. Our data are in line with a model in which CAP2 controls the MRTF-SRF pathway in an actin-dependent manner. While MRTF-A localization and SRF activity was impaired under basal conditions, serum stimulation induced nuclear MRTF-A translocation and SRF activity in mutant MEFs similar to controls. In summary, our data revealed that in MEFs CAP2 controls basal MRTF-A localization and SRF activity, while it was dispensable for serum-induced nuclear MRTF-A translocation and SRF stimulation.

Amyotrophy Induced by a High-Fat Diet Is Closely Related to Inflammation and Protein Degradation Determined by Quantitative Phosphoproteomic Analysis in Skeletal Muscle of C57BL/6 J Mice

Ectopic fat accumulation in skeletal muscle results in dysfunction and atrophy, but the underlying molecular mechanisms remain unclear. The aim of this study was to investigate the effects of a high-fat diet (HFD) in modulating the structure and energy metabolism of skeletal muscle and the underlying mechanisms in mice. Four-week-old male C57BL/6 J mice (n=30) were allowed 1 wk for acclimatization. After 6 mice with low body weight were removed from the study, the remaining 24 mice were fed with a normal-fat diet (NFD; 10% energy from fat, n=12) or an HFD (60% energy from fat, n=12) for 24 wk. At the end of the experiment, serum glucose and lipid concentrations were measured, and skeletal muscle was collected for atrophy analysis, inflammation measurements, and phosphoproteomic analysis. Compared with the NFD, the HFD increased (P<0.05) body weight (35.8%), serum glucose (64.5%), and lipid (27.3%) concentrations, along with elevated (P<0.05) expressions of the atrophy-related proteins muscle ring finger 1 (MURF1; 27.6%) and muscle atrophy F-box (MAFBX; 44.5%) in skeletal muscle. Phosphoproteomic analysis illustrated 64 proteins with differential degrees of phosphorylation between the HFD and NFD groups. These proteins were mainly involved in modulating cytoskeleton [adenylyl cyclase-associated protein 2 (CAP2) and actin-α skeletal muscle (ACTA1)], inflammation [NF-κB-activating protein (NKAP) and serine/threonine-protein kinase RIO3 (RIOK3)], glucose metabolism [Cdc42-interacting protein 4 (TRIP10); protein kinase C, and casein kinase II substrate protein 3 (PACSIN3)], and protein degradation [heat shock protein 90 kDa (HSP90AA1)]. The HFD-induced inhibitions of the insulin signaling pathway and activations of inflammation in skeletal muscle were verified by Western blot analysis. Quantitative phosphoproteomic analysis in C57BL/6 J mice fed an NFD or HFD for 24 wk revealed that the phosphorylation of inflammatory proteins and proteins associated with glucose metabolism at specific serine residues may play critical roles in the regulation of skeletal muscle atrophy induced by an HFD. This work provides information regarding underlying molecular mechanisms for inflammation-induced dysfunction and atrophy in skeletal muscle.

Prognostic impact of adenylyl cyclase-associated protein 2 (CAP2) in glioma: A clinicopathological study

BackgroundGliomas are a group of diseases arising from intracranial neoplastic tissues that produce a wide spectrum of clinicopathological features and morphological changes. Key questions that intrigue neuro-oncology researchers include defining novel oncophenotypic signatures relevant to diagnosing such tumors and predicting prognoses among patients. One of the key regulators of the cellular actin dynamics is adenylyl cyclase-associated protein 2 (CAP2), a protein that has been studied before in the milieu of cancer and shown to be associated with tumor progression; yet, its expression levels in the context of gliomas have not been assessed. Hence, we were interested in investigating CAP2 expression in gliomas and evaluating its clinicopathological and prognostic significance. Materials and methodsCAP2 expression at the protein level was analyzed in 47 human paraffin-embedded gliomas and normal brain tissues by automated immunohistochemical analysis. Statistical analysis was also performed to assess CAP2 expression level in normal and tumor tissues, and to evaluate its clinicopathological and prognostic significance. ResultsOur results revealed high expression of CAP2 protein in tumors of gliomas compared to normal tissues and normal areas adjacent to tumors. High expression of CAP2 was also associated with advanced tumor grades among gliomas. Kaplan-Meier analysis revealed that high CAP2 expression was associated with poor prognosis of patients with glioma (P < 0.05). In Cox regression analysis, CAP2 expression was indicated as an independent prognostic factor for overall survival (hazard ratio (HR) = 1.843, 95% confidence interval (CI), 1.252–2.714; P < 0.005). ConclusionCAP2 is overexpressed in glioma and it is proposed as a potential prognostic biomarker for patients with gliomas. CAP2 expression level may serve as a promising target for diagnosis and treatment of glioma.

Association of adenylate cyclase-associated protein 2 expression with histopathology and long-term prognosis of gastric cancer

To explore association of the expression levels of adenylate cyclase-associated protein 2 (CAP2) in gastric cancer tissues with the histopathology and long-term prognosis of the malignancy. This study was conducted among a total of 105 patients with gastric cancer undergoing radical gastrectomy in our hospital between January, 2010 and October, 2013. Immunohistochemistry was used to quantitatively assess the expression of CAP2 in gastric cancer tissues and the adjacent tissues. Based on the median relative expression level of CAP2 of 3.5, the patients were divided into low CAP2 expression group (n=52) and high CAP2 expression group (n=53). The Cox regression model was used to analyze the effect of CAP2 expression on the 5-year survival rate of the patients, and ROC curve analysis was used to assess the predictive value of CAP2 expression for the patients' long-term survival. Immunohistochemical analysis showed that the expression levels of CAP2 (P &lt; 0.01) and Ki67 (P &lt; 0.01) were significantly higher in gastric cancer tissues than in the adjacent tissues, and the expression level of CAP2 was positively correlated with Ki67 (P &lt; 0.01), peripheral blood CEA (P &lt; 0.01) and CA19-9 (P &lt; 0.01). The percentages of patients with CEA≥5 μg/L, CA19-9≥37 kU/L, pathological grade of G3-G4, T stage of 3-4, and N stage of 2-3 were significantly higher in patients with high CAP2 expression than in those with low CAP2 expression (P &lt; 0.05). Kaplan- Meier survival analysis showed that the 5-year survival rate was significantly lower in patients with a high CAP2 expression (P &lt; 0.01). A high expression level of CAP2, CEA≥5μg/L, CA19-9≥37 and pathological grades G3-G4 were all independent risk factors for shortened 5-year survival after radical gastrectomy (P &lt; 0.01). With the relative expression level of 3.45 as the cut-off value, the sensitivity of CAP2 was 70.15% for predicting death 5 years after the surgery, with a specificity of 71.05% and an area under the curve of 0.779 (P &lt; 0.01). CAP2 is highly expressed in gastric cancer tissues in close relation with the tumor progression. CAP2 is an independent risk factor for 5-year survival rate after radical gastrectomy for gastric cancer and can be of clinical value in prognostic evaluation of the patients.

CAP2 deficiency delays myofibril actin cytoskeleton differentiation and disturbs skeletal muscle architecture and function

Actin filaments (F-actin) are key components of sarcomeres, the basic contractile units of skeletal muscle myofibrils. A crucial step during myofibril differentiation is the sequential exchange of α-actin isoforms from smooth muscle (α-SMA) and cardiac (α-CAA) to skeletal muscle α-actin (α-SKA) that, in mice, occurs during early postnatal life. This "α-actin switch" requires the coordinated activity of actin regulators because it is vital that sarcomere structure and function are maintained during differentiation. The molecular machinery that controls the α-actin switch, however, remains enigmatic. Cyclase-associated proteins (CAP) are a family of actin regulators with largely unknown physiological functions. We here report a function for CAP2 in regulating the α-actin exchange during myofibril differentiation. This α-actin switch was delayed in systemic CAP2 mutant mice, and myofibrils remained in an undifferentiated stage at the onset of the often excessive voluntary movements in postnatal mice. The delay in the α-actin switch coincided with the onset of motor function deficits and histopathological changes including a high frequency of type IIB ring fibers. Our data suggest that subtle disturbances of postnatal F-actin remodeling are sufficient for predisposing muscle fibers to form ring fibers. Cofilin2, a putative CAP2 interaction partner, has been recently implicated in myofibril actin cytoskeleton differentiation, and the myopathies in cofilin2 and CAP2 mutant mice showed striking similarities. We therefore propose a model in which CAP2 and cofilin2 cooperate in actin regulation during myofibril differentiation.

CAP2 is a Valuable Biomarker for Diagnosis and Prognostic in Patients with Gastric Cancer.

Cyclase-associated protein 2 (CAP2) protein is reported to be upregulated in hepatocellular carcinoma (HCC), human breast cancer, and malignant melanoma. However, its expression in gastric cancer remains unknown, this study was to investigate CAP2 expression and its prognostic significance in gastric cancer. Firstly, we analyzed the Oncomine databases to compare CAP2 mRNA expression in gastric cancer and normal tissues. CAP2 protein expression was analyzed in gastric cancer samples and non-tumor mucosa by RT-PCR and immunohistochemical analysis. Consequently, statistical analyses were performed to evaluate the clinicopathological significance of CAP2 expression in gastric cancer. CAP2 expression was significant higher in gastric cancer tissues than that in non-tumor mucosa at protein levels. CAP2 was up-regulated in 57.8% (252/436) of gastric cancer samples, while detected in only 10.9% (10/92) of non-tumor mucosa. Statistical analysis shows that the expression of CAP2 was correlated with tumor size, Lauren's classification, depth of invasion, lymph node and distant metastases, and regional lymph node stage, TNM stage, but not with age, sex, histology classification, and histologic differentiation. Kaplan-Meier analysis indicated that high CAP2 expression was associated with poor overall survival (78.7%) in 203 of 252 gastic cancer patients. In stage I, II, and III tumors, the 5-year survival rate was lower in those with high expression of CAP2 than those with low expression. In stage IV tumors, the expression of CAP2 did not correlate with the 5-year survival rate. Multiple Cox regression analysis indicated CAP2 as an independent predictor for overall survival [hazard ratio (HR) = 2.045, 95% confidence interval: 1.445-2.895, p < 0.01], while Lauren's classification, TNM stage, and expression of CAP2 were independent prognostic factors in patients with gastric cancer. For the first time, we found that CAP2 was upregulated in gastic cancer, and was associated with lymph node and distant metastases. CAP2 may serve as a prognostic indicator for patients with gastic cancer.

Erratum to: Ablation of cyclase-associated protein 2 (CAP2) leads to cardiomyopathy.

Erratum to: Ablation of cyclase-associated protein 2 (CAP2) leads to cardiomyopathy.

Identification of Cyclase-Associated Protein-2 as a Novel Biomarker for Early- Stage Hepatocellular Carcinoma

Background: Hepatocellular carcinoma (HCC) is an aggressive deadly cancer with few therapeutic options mostly limited for early-stage HCC. Unfortunately, alphafetoprotein (AFP) has a limited performance, especially in early-stage HCC. Objectives: to investigate plasma levels of Cyclaseassociated protein-2 (CAP2) as a new biomarker and evaluate its role in detecting early-stage and AFP-negative HCC Egyptian patients. Methods: Plasma CAP2 and AFP levels in 150 HCC, 150 cirrhotic patients, 150 healthy controls. Correlation with tumor behavior, the area under the curve (AUC), sensitivity, specificity, and diagnostic accuracy were analyzed. Results: Plasma CAP2 and AFP levels were significantly elevated in HCC patients than liver cirrhosis and controls. Only plasma CAP2 levels significantly correlated with clinico-pathological characteristics of HCC (BCLC, histological and clinical stages) but not correlated with patient's age, gender, viral infection status or AFP levels. Compared to AFP, CAP2 had significantly higher AUC: 0.86 (0.79-0.93) vs. 0.75 (0.65-0.85), Sensitivity: 81.5% vs. 62% in all HCCs and significantly higher AUC: 0.80 (0.72-0.89) vs. 0.68 (0.58-0.79, Sensitivity: 80.5% vs. 43.1% in earlystage HCC. Moreover, the combined diagnostic value of both CAP2+AFP was statistically significantly better than either CAP2 or AFP alone. Also, CAP2 could predict 82.4% of AFP-negative HCCs [AUC: 0.85 (0.77-0.92)] and 73.5% of AFP-negative early-stage HCCs [AUC: 0.80 (0.72-0.88)]. Conclusion: Compared with AFP, CAP2 was significantly elevated in HCC patients with higher sensitivity and AUC especially for early-stage HCC. Moreover, CAP2 was significantly correlated with the clinico-pathological features of HCC. CAP2 could be a novel biomarker predicting early-stage, AFP-negative, and AFP-negative early-stage HCC patients.

Expression status of cyclase-associated protein 2 as a prognostic marker for human breast cancer

Cyclase-associated protein2(CAP2) protein is reported to be upregulated in hepatocellular carcinoma(HCC). However, data regarding its expression pattern and clinical relevance in breast cancer are unknown. The aim of this study was to investigate CAP2 expression and its prognostic significance in breast cancer. CAP2 expression at the mRNA and protein levels was examined by real‑time quantitative-polymerase chain reactionand western blotting in 10paired breast cancer tissues and adjacent normal tissues. The expression level of CAP2 protein in normal breast epithelial cells and breast cancer cell lines was quantified by western blotting. CAP2 protein expression was analyzed in paraffin‑embedded breast cancer samples, paired adjacent non‑tumor and normal breast tissues by immunohistochemicalanalysis. Statistical analyses were also performed to evaluate the clinicopathological significance of CAP2 expression. The results showed that the expression of CAP2 mRNA and protein was higher in breast cancer than that noted in the adjacent normal tissues in 10paired samples. The expression level of CAP2 protein in breast cancer cell lines was higher than that in normal breast epithelial cells. In paraffin‑embedded tissue samples, the expression of CAP2 was higher in breast cancer than that found in the adjacent non‑cancerous tissues and normal breast tissues. Compared with the adjacent non‑cancerous tissues, overexpression of CAP2 was detected in 29.4% (37/126) of the patients. Overexpression of CAP2 was significantly associated with progesterone receptor(PR) expression (p<0.05), and decreased overall survival(OS) (p<0.05). In multivariate analysis, expression of CAP2 was an independent prognostic factor for OS [hazard ratio(HR), 4.821; 95% confidence interval(CI), 2.442‑9.518; p<0.001]. CAP2 is upregulated in breast cancer and is associated with the expression of PR and patient survival. CAP2 may serve as a prognostic indicator for patients with breast cancer.

Early hepatocellular carcinoma with high-grade atypia in small vaguely nodular lesions.

Multistep hepatocarcinogenesis progresses from dysplastic nodules to early hepatocellular carcinoma (eHCC) and to advanced HCC. The aim of the present study was to investigate the detailed histopathological features of eHCC. We investigated 66 small vaguely nodular lesions resected from 40 patients. The degree of cellular and structural atypia and stromal invasion were assessed. The immunohistochemical expression of HCC‐related markers adenylate cyclase‐associated protein 2 (CAP2), heat shock protein 70 (HSP70), Bmi‐1, CD34 and h‐caldesmon were evaluated. Of the 66 nodules, 10 were diagnosed as low‐grade dysplastic nodules (LGDN), 10 as high‐grade dysplastic nodules (HGDN) and 46 as eHCC. Among the 46 eHCC, 18 nodules (39.1%) showed marked stromal invasion and/or the presence of the scirrhous component and were subclassified as high‐grade eHCC (HGeHCC). The remaining 28 eHCC, which lacked these features, were subclassified as low‐grade eHCC (LGeHCC) and were examined further. HGeHCC showed high levels of cellular and structural atypia and large tumor size. The immunohistochemical expression of CAP2 and the area of sinusoidal vascularization showed increases from LGDN to HGeHCC. The density of arterial tumor vessels was high in HGeHCC compared with other nodule types. Cluster analysis of these parameters subclassified 65 nodules into HGeHCC‐dominant, LGeHCC and HGDN‐dominant, and LGDN‐dominant groups. These results indicate the increased malignant potential of HGeHCC and suggest that it is already a transitional stage to advanced HCC. We consider that our grading classification system may be valuable for considering treatment strategies for eHCC around 2 cm in diameter.

Deficiency of cyclase-associated protein 2 promotes arrhythmias associated with connexin43 maldistribution and fibrosis

IntroductionCyclase-associated protein 2 (CAP2) plays a major role in regulating the actin cytoskeleton. Since inactivation of CAP2 in a mouse model by a gene trap approach (Cap2gt/gt) results in cardiomyopathy and increased mortality, we hypothesized that CAP2 has a major impact on arrhythmias and electrophysiological parameters.Material and methodsWe performed long-term-ECG recordings in transgenic CAP2 deficient mice (C57BL/6) to detect spontaneous arrhythmias. In vivo electrophysiological studies by right heart catheterization and ex vivo epicardial mapping were used to analyze electrophysiological parameters, the inducibility of arrhythmias, and conduction velocities. Expression and distribution of cardiac connexins and the amount of cardiac fibrosis were evaluated.ResultsSpontaneous ventricular arrhythmias could be detected in Cap2gt/gt during the long-term-ECG recording. Cap2gt/gt showed marked conduction delays at atrial and ventricular levels, including a reduced heart rate (421.0 ±40.6 bpm vs. 450.8 ±27.9 bpm; p < 0.01), and prolongations of PQ (46.3 ±4.1 ms vs. 38.6 ±6.5 ms; p < 0.01), QRS (16.2 ±2.6 ms vs. 12.6 ±1.4 ms; p < 0.01), and QTc interval (55.8 ±6.0 ms vs. 45.2 ±3.3 ms; p = 0.02) in comparison to wild type mice. The PQ prolongation was due to an infra-Hisian conduction delay (HV: 9.7 ±2.1 ms vs. 6.5 ±3.1 ms; p = 0.02). The inducibility of ventricular tachycardias during the electrophysiological studies was significantly elevated in the mutant mice (inducible animals: 88% vs. 33%; p = 0.04). Cap2gt/gt showed more abnormal distribution of connexin43 compared to WT (23.0 ±4.7% vs. 2.9 ±0.8%; p < 0.01). Myocardial fibrosis was elevated in Cap2gt/gt hearts (9.1 ±6.7% vs. 5.5 ±3.3%; p < 0.01).ConclusionsLoss of CAP2 results in marked electrophysiological disturbances including impaired sinus node function, conduction delays, and susceptibility to malignant arrhythmias. Structural changes in Cap2gt/gt are associated with alterations in myocardial connexins and fibrosis.

Overexpression of adenylate cyclase-associated protein 2 is a novel prognostic marker in malignant melanoma.

Malignant melanoma is one of the lethal malignant tumors worldwide. Previously we reported that adenylate cyclase-associated protein 2 (CAP2), which is a well-conserved actin regulator, was overexpressed in hepatocellular carcinoma; however, CAP2 expression in other clinical cancers remains unclear. The aim of the current study was to clarify the clinicopathological significance of CAP2 overexpression in malignant melanoma. Immunohistochemical analyses revealed that many melanoma cells exhibited diffuse cytoplasmic expression of CAP2, whereas no normal melanocytes showed detectable immunostaining for CAP2. A high level of CAP2 expression was seen in 14 of 50 melanomas and was significantly correlated with greater tumor thickness and nodular melanoma subtypes. In addition, a high level of CAP2 expression was associated with poor overall survival in univariate and multivariate analyses. For 13 patients, samples of primary and metastatic melanoma tissue were available: four patients exhibited higher levels of CAP2 expression in metastatic tumor compared to the primary site, whereas no patient showed lower levels of CAP2 expression in metastatic melanomas. Our findings show that CAP2 overexpression is a novel prognostic marker in malignant melanoma and that CAP2 expression seems to increase stepwise during tumor progression, suggesting the involvement of CAP2 in the aggressive behavior of malignant melanoma.