TaCAP1 Interacts with TaLHCB1s and Positively Regulates Wheat Resistance Against Stripe Rust.

Actin filaments and their associated actin-binding proteins play key roles in plant innate immune signaling. CAP1, or cyclase-associated protein 1, is an important regulatory factor of the actin cytoskeleton-associated signaling network and was hypothesized here to be involved in resistance against wheat stripe rust because TaCAP1 expression was upregulated in response to Puccinia striiformis f. sp. tritici (Pst). Downregulation of TaCAP1 expression led to decreased resistance against Pst, in contrast to increased resistance upon TaCAP1 overexpressing, as demonstrated by the changes of phenotypes and hyphal growth. We found increased expression of pathogenesis-responsive or relative related genes and disease grade changed in TaCAP1 overexpressing plants. Our results also showed TaCAP1-regulated host resistance to Pst by inducing the production and accumulation of reactive oxygen species and mediating the salicylic acid signaling pathway. Additionally, TaCAP1 interacted with chlorophyll a/b-binding proteins TaLHCB1.3 and TaLHCB1.4, also known as the light-harvesting chlorophyll-protein complex II subunit B, which belong to the light-harvesting complex II protein family. Silencing of two TaLHCB1 genes showed higher susceptibility to Pst, which reduced wheat resistance against Pst. Therefore, the data presented herein further illuminate our understanding that TaCAP1 interacts with TaLHCB1s and functions as a positive regulator of wheat resistance against stripe rust.

CAP1 (cyclase-associated protein 1) mediates the cyclic AMP signals that activate Rap1 in stimulating matrix adhesion of colon cancer cells.

We previously reported that CAP1 (Cyclase-Associated Protein 1) regulates matrix adhesion in mammalian cells through FAK (Focal Adhesion Kinase). More recently, we discovered a phosphor-regulation mechanism for CAP1 through the Ser307/Ser309 tandem site that is of critical importance for all CAP1 functions. However, molecular mechanisms underlying the CAP1 function in adhesion and its regulation remain largely unknown. Here we report that Rap1 also facilitates the CAP1 function in adhesion, and more importantly, we identify a novel signaling pathway where CAP1 mediates the cAMP signals, through the cAMP effectors Epac (Exchange proteins directly activated by cAMP) and PKA (Protein Kinase A), to activate Rap1 in stimulating matrix adhesion in colon cancer cells. Knockdown of CAP1 led to opposite adhesion phenotypes in SW480 and HCT116 colon cancer cells, with reduced matrix adhesion and reduced FAK and Rap1 activities in SW480 cells while it stimulated matrix adhesion as well as FAK and Rap1 activities in HCT116 cells. Importantly, depletion of CAP1 abolished the stimulatory effects of the cAMP activators forskolin and isoproterenol, as well as that of Epac and PKA, on matrix adhesion in both cell types. Our results consistently support a required role for CAP1 in the cAMP activation of Rap1. Identification of the key role for CAP1 in linking the major second messenger cAMP to activation of Rap1 in stimulating adhesion, which may potentially also regulate proliferation in other cell types, not only vertically extends our knowledge on CAP biology, but also carries important translational potential for targeting CAP1 in cancer therapeutics.

Chromenopyrimidinone exhibit antitumor effects through inhibition of CAP1 (Adenylyl cyclase-associated protein 1) expression in hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is one of the most malignant human cancers, with a high mortality rate worldwide. Within an HCC tumor, cancer stem cells (CSCs) are responsible for tumor maintenance and progression and may contribute to resistance to standard HCC treatments. Previously, we characterized CD133+ cells as CSCs in primary HCC and identified chromenopyrimidinone (CPO) as a novel therapeutic for the effective treatment of CD133+ HCC. However, the biological function and molecular mechanism of CD133 remain unclear. Epigenetic alterations of CSCs have impacts on tumor initiation, progression, and therapeutic response. Here, we found that pharmacological and genetic depletion of CD133 in HCC attenuated the activity of DNA methyltransferases via control of DNMT3B stabilization. Genes were ranked by degree of promoter hypo/hyper methylation and significantly differential expression to create an "epigenetically activated by CPO" ranked genes list. Through this epigenetic analysis, we found that CPO treatment altered DNA methylation-mediated oncogenic signaling in HCCs. Specifically, CPO treatment inhibited Adenylyl cyclase-associated protein 1 (CAP1) expression, thereby reducing FAK/ERK activity and EMT-related proteins in HCC. Moreover, CPO improved the efficacy of sorafenib by inhibiting CAP1 expression and FAK/ERK activation in sorafenib-resistant HCC. These novel mechanistic insights may ultimately open up avenues for strategies targeting DNA methylation in liver cancer stem cells and provides novel therapeutic function of CPO for the effective treatment of sorafenib-resistant HCC.

A pilot study of the relative number of circulating tumor cells and leukocytes containing actin-binding proteins in head and neck cancer patients.

Circulating tumor cells (CTCs) play an important role in tumor metastases, which is positively correlated with an increased risk of death. Actin-binding proteins, including cofilin (CFL1), profilin 1 (PFN1), and adenylate cyclase-associated protein 1 (CAP1), are thought to be involved in tumor cell motility and metastasis, specifically in head and neck squamous cell carcinoma (HNSCC). However, currently, there are no published studies on CFL1, PFN1, and CAP1 in CTCs and leukocytes in HNSCC patients. We assessed serum levels of CFL1, PFN1, and CAP1 and the number of CTCs and leukocytes containing these proteins in blood from 31 HNSCC patients (T1-4N0-2M0). The analysis used flow cytometry and an enzyme-linked immunosorbent assay kit. We found that CAP1 + CTCs and CAP1 + leukocyte subpopulations were prevalent in these HNSCC patient samples, while the prevalence rates of CFL1 + and PFN1 + CTCs were relatively low. Patients with stage T2-4N1-2M0 had CFL1 + and PFN1 + CTCs with an elevated PFN1 serum level, compared with the T1-3N0M0 group. In summary, the PFN1 serum level and the relative number of PFN1 +CD326 + CTCs could be valuable prognostic markers for HNSCC metastases. The current study is the first to obtain data regarding the contents of actin-binding proteins (ABPs) in CTCs, and leukocytes in blood from HNSCC patients. This is also the first to assess the relationship between the number of CTCs subgroups and disease characteristics.

Reduced tissue and serum resistin expression as a clinical marker for esophageal squamous cell carcinoma.

Esophageal cancer is one of the most common malignancies and leading cause of cancer-associated mortality worldwide. However, the molecular mechanisms underlying esophageal cancer progression and the development of clinical tools for effective diagnosis remain unclear. Resistin, which was originally identified as an adipose tissue-secretory factor, has been associated with obesity-related diseases, including certain types of cancer. Thus, the present study aimed to investigate the expression levels of resistin in tissue and serum specimens from patients with esophageal squamous cell carcinoma (ESCC) to determine the potential biological effects of resistin on ESCC cells. The results demonstrated that both tissue and serum resistin levels were significantly lower in patients with ESCC compared with healthy controls. In addition, resistin expression was positively associated with the body mass index of patients with ESCC. In vitro studies revealed that resistin inhibited the migratory ability of ESCC cells, while having no effect on ESCC cell proliferation. Taken together, these results suggest that resistin may have the potential to be developed into a clinical marker for ESCC. However, further studies are required to investigate resistin receptor expression and determine the potential involvement of resistin-associated biological pathways, which may provide insight for future development of targeted therapies for resistin-mediated ESCC.

Persistent Infection of Simian Foamy Virus Derived from the Japanese Macaque Leads to the High-Level Expression of microRNA that Resembles the miR-1 microRNA Precursor Family.

MicroRNAs (miRNAs) are a group of small non-coding RNAs that suppress the expression of target mRNAs. The seed sequence of miRNA plays a crucial role in recognizing the 3'-untranslated region of the target mRNA. Cells infected with a simian foamy virus (SFV) isolated from an African green monkey (Chlorocebus aethiops) (SFVcae) showed high expression levels of viral miRNAs encoded in the long terminal repeat of SFVcae. In the present study, we investigated the roles and expression of miRNAs derived from an SFV isolated from a Japanese macaque (Macaca fuscata) (SFVmfu) using next-generation sequencing technologies. The results obtained showed that SFVmfu also expressed viral miRNAs; however, the seed sequences of most miRNAs derived from SFVmfu differed from those reported previously from SFVcae. Cells persistently infected with SFVmfu strongly expressed an miRNA with the same seed sequence as the miR-1 microRNA precursor family. Luciferase reporter assays indicated that this miRNA down-regulates the expression of adenylyl cyclase-associated protein 1, which is up-regulated in several solid tumors. The present results suggest that SFVmfu utilizes viral miRNAs to establish long-term co-existence with the Japanese macaque.

Cyclase-associated protein 1 is a binding partner of proprotein convertase subtilisin/kexin type-9 and is required for the degradation of low-density lipoprotein receptors by proprotein convertase subtilisin/kexin type-9.

AIMS: Proprotein convertase subtilisin/kexin type-9 (PCSK9), a molecular determinant of low-density lipoprotein (LDL) receptor (LDLR) fate, has emerged as a promising therapeutic target for atherosclerotic cardiovascular diseases. However, the precise mechanism by which PCSK9 regulates the internalization and lysosomal degradation of LDLR is unknown. Recently, we identified adenylyl cyclase-associated protein 1 (CAP1) as a receptor for human resistin whose globular C-terminus is structurally similar to the C-terminal cysteine-rich domain (CRD) of PCSK9. Herein, we investigated the role of CAP1 in PCSK9-mediated lysosomal degradation of LDLR and plasma LDL cholesterol (LDL-C) levels. METHODS AND RESULTS: The direct binding between PCSK9 and CAP1 was confirmed by immunoprecipitation assay, far-western blot, biomolecular fluorescence complementation, and surface plasmon resonance assay. Fine mapping revealed that the CRD of PCSK9 binds with the Src homology 3 binding domain (SH3BD) of CAP1. Two loss-of-function polymorphisms found in human PCSK9 (S668R and G670E in CRD) were attributed to a defective interaction with CAP1. siRNA against CAP1 reduced the PCSK9-mediated degradation of LDLR in vitro. We generated CAP1 knock-out mice and found that the viable heterozygous CAP1 knock-out mice had higher protein levels of LDLR and lower LDL-C levels in the liver and plasma, respectively, than the control mice. Mechanistic analysis revealed that PCSK9-induced endocytosis and lysosomal degradation of LDLR were mediated by caveolin but not by clathrin, and they were dependent on binding between CAP1 and caveolin-1. CONCLUSION: We identified CAP1 as a new binding partner of PCSK9 and a key mediator of caveolae-dependent endocytosis and lysosomal degradation of LDLR.

Serum Resistin, Adenylate Cyclase-Associated Protein 1 Gene Expression, and Carotid Intima-Media Thickness in Patients with End-Stage Renal Disease and Healthy Controls.

BACKGROUND: Human resistin is a proinflammatory cytokine with significant proatherogenic effects which acts through adenylyl cyclase-associated protein 1 (CAP1). Chronic kidney disease (CKD) and end-stage renal disease (ESRD) patients have increased cardiovascular risk and resistin levels. Previous studies indicated resistin significance as a predictor of mortality in CKD. AIMS: We sought to investigate plasma resistin levels, peripheral blood mononuclear cell (PBMC) resistin mRNA, and for the first time CAP1 mRNA levels in ESRD patients and healthy controls. We also sought to investigate the relation of resistin and CAP1 to carotid intima media thickness (CIMT), CD36 gene expression, and matrix metalloproteinase 9 (MMP-9) circulating levels in ESRD patients and healthy controls. METHODS: This study included 33 patients with ESRD and 27 healthy controls. Resistin and MMP-9 levels were measured by ELISA. Resistin, CAP1, and CD36 PBMC mRNA were measured by quantitative PCR. RESULTS: Our study showed that ESRD patients have significantly higher levels of circulatory resistin compared to healthy controls (p < 0.001), while there was no significant difference in resistin mRNA. A significant upregulation of CAP1 and CD36 was observed in the ESRD group (p < 0.001; p < 0.001). Resistin concentration correlated with CIMT in healthy controls (r = 0.512, p = 0.036), and with MMP-9 concentration in ESRD (r = 0.353, p = 0.044) and healthy controls (r = 0.463, p = 0.026). CAP1 correlated positively with CIMT (r = 0.464, p = 0.008) in ESRD, and with CD36 in healthy controls (r = 0.447, p = 0.022) and ESRD (r = 0.824, p < 0.001). CONCLUSION: The obtained data suggest that high levels of circulating resistin acting upon cells with an upregulated CAP1 gene could contribute to the increased inflammation and accelerated atherosclerosis seen in CKD patients.

Association among resistin, adenylate cyclase-associated protein 1 and high-density lipoprotein cholesterol in patients with colorectal cancer: a multi-marker approach, as a hallmark of innovative predictive, preventive, and personalized medicine.

BACKGROUND: Elevated concentrations of resistin have been reported in colorectal cancer (CRC), but its interactions with adenylate cyclase-associated protein 1 (CAP-1) are largely unexplored. We investigated resistin plasma concentration, peripheral blood mononuclear cells (PBMCs) resistin messenger ribonucleic acid (mRNA), and CAP-1 mRNA levels in CRC patients, as well as the impact of resistin gene polymorphism rs1862513 on the examined markers. We also explored associations of resistin with high-density lipoprotein cholesterol (HDL-C) and predictive potential of our parameters for CRC. METHODS: Eighty-six patients with CRC and 75 healthy adults were included. Commercial ELISA kit was used for obtaining resistin's concentrations, while polymerase chain reaction (PCR) method was applied for evaluation of resistin and CAP-1 mRNA levels and rs1862513 polymorphism. RESULTS: Plasma resistin and CAP-1 mRNA levels were higher in CRC patients (p < 0.001 and p < 0.05, respectively), while resistin mRNA levels were lower (p < 0.001). Negative association existed among plasma resistin and HDL-C concentrations (ρ = - 0.280; p < 0.05). A model including age, body-mass index, HDL-C, low-density lipoprotein cholesterol (LDL-C), and plasma resistin concentrations as independent predictors of CRC showed very good diagnostic accuracy (AUC = 0.898). We found no associations of rs1862513 with the examined markers. CONCLUSIONS: Our study demonstrated increased plasma resistin and CAP-1 mRNA levels, implying their possible interaction in CRC. The association among plasma resistin and HDL-C might indicate that HDL-C is involved in alterations of resistin's secretion process. As a hallmark of personalized medicine, multi-marker approach in determination of resistin-related parameters might be useful for prediction and prevention of CRC development.

Resistin and adenylyl cyclase-associated protein 1 (CAP1) regulate the expression of genes related to insulin resistance in BNL CL.2 mouse liver cells.

Resistin is an adipokine produced in white adipose tissue that is thought to modulate insulin sensitivity in peripheral tissues (such as liver, skeletal muscle or adipose tissue). Human and murine resistin molecules share only about 60% sequence homology. [1] Contrary to humans, in which resistin is secreted mostly by macrophages, Park and Ahima 2013 resistin in rodents is produced primarily by the mature adipocytes of the white adipose tissue. Although resistin can bind to toll-like receptor 4 (TLF4) activating proinflammatory responses in human and rodents, [3], [4], [5], [6], [7], [8] the inflammatory actions of resistin in human monocytes were found to be mediated by resistin binding to adenylyl cyclase-associated protein 1 (CAP1). [9] In this study, we aimed to investigate the in vitro effects of resistin on the expression of various genes related to insulin resistance in mouse liver cells. Using BNL CL.2 cells, we investigated the effect of resistin in untransfected or CAP1 siRNA-transfected cells on the expression of 84 key genes involved in insulin resistance.

Adenylate Cyclase-Associated Protein 1 and Cofilin in Progression of Non-Small Cell Lung Cancer.

We studied the expression of mRNA and the level of CAP1 (adenylate cyclase-associated protein 1) and cofilin proteins in the tissues of patients with non-small cell lung cancer. The expression of mRNA and the level of CAP1 in tumor tissue increased during growth of the primary tumor and its metastasis. It was shown that with the growth of the primary tumor, the content of cofilin in the tumor tissue decreases against the background of increased expression of its mRNA; in regional metastasis, the content of cofilin and expression of the corresponding mRNA increased. It was found that increased content of the studied proteins in the tumor tissue increased the risk of metastasis.

Cyclase-associated protein 1 (CAP1) is a prenyl-binding partner of Rap1 GTPase.

Rap1 proteins are members of the Ras subfamily of small GTPases involved in many biological responses, including adhesion, cell proliferation, and differentiation. Like all small GTPases, they work as molecular allosteric units that are active in signaling only when associated with the proper membrane compartment. Prenylation, occurring in the cytosol, is an enzymatic posttranslational event that anchors small GTPases at the membrane, and prenyl-binding proteins are needed to mask the cytoplasm-exposed lipid during transit to the target membrane. However, several of these proteins still await discovery. In this study, we report that cyclase-associated protein 1 (CAP1) binds Rap1. We found that this binding is GTP-independent, does not involve Rap1's effector domain, and is fully contained in its C-terminal hypervariable region (HVR). Furthermore, Rap1 prenylation was required for high-affinity interactions with CAP1 in a geranylgeranyl-specific manner. The prenyl binding specifically involved CAP1's C-terminal hydrophobic ß-sheet domain. We present a combination of experimental and computational approaches, yielding a model whereby the high-affinity binding between Rap1 and CAP1 involves electrostatic and nonpolar side-chain interactions between Rap1's HVR residues, lipid, and CAP1 ß-sheet domain. The binding was stabilized by the lipid insertion into the ß-solenoid whose interior was occupied by nonpolar side chains. This model was reminiscent of the recently solved structure of the PDEδ-K-Ras complex; accordingly, disruptors of this complex, e.g. deltarasin, blocked the Rap1-CAP1 interaction. These findings indicate that CAP1 is a geranylgeranyl-binding partner of Rap1.

Resistin upregulates chemokine production by fibroblast-like synoviocytes from patients with rheumatoid arthritis.

BACKGROUND: Adipokines are bioactive hormones secreted by adipose tissues. Resistin, an adipokine, plays important roles in the regulation of insulin resistance and inflammation. Resistin levels are known to be increased in the serum and synovial fluid of rheumatoid arthritis (RA) patients. However, the pathogenic role of resistin in RA has not yet been elucidated. METHODS: The expression of resistin and adenylate cyclase-associated protein 1 (CAP1), a receptor for resistin, was examined immunohistochemically in synovial tissue. CAP1 expression in in vitro cultured fibroblast-like synoviocytes (FLSs) was assessed with a reverse transcription-polymerase chain reaction (PCR) and western blotting. The gene expression of resistin-stimulated FLSs was evaluated by RNA sequencing (RNA-Seq) and quantitative real-time PCR. Concentrations of chemokine (C-X-C motif) ligand (CXCL) 8, chemokine (C-C motif) ligand (CCL) 2, interleukin (IL)-1ß, IL-6 and IL-32 in culture supernatants were measured by enzyme-linked immunosorbent assay. Small interfering RNA (siRNA) for CAP1 was transfected into FLSs in order to examine inhibitory effects. RESULTS: The expression of resistin and CAP1 in synovial tissue was stronger in RA than in osteoarthritis (OA). Resistin was expressed by macrophages in the RA synovium, while CAP1 was expressed by macrophages, FLSs and endothelial cells. In vitro cultured RA FLSs also expressed CAP1. RNA-Seq revealed that the expression levels of 18 molecules were more than twofold higher in resistin-stimulated FLSs than in unstimulated FLSs. Seven chemokines, CXCL1, CXCL2, CXCL3, CXCL5, CXCL6, CXCL8, and CCL2, were included among the 18 molecules. Increases induced in the expression of CXCL1, CXCL8, and CCL2 by the resistin stimulation were confirmed by real-time PCR. The stimulation with resistin increased the protein levels of CXCL8 and CCL2 produced by RA FLSs, and the upregulated expression of CXCL8 was inhibited by the abrogation of CAP1 by siRNA for CAP1. Production of IL-6 by FLSs was also increased by resistin. Expression of IL-1ß and IL-32 was not detected by ELISA. CONCLUSIONS: Resistin contributes to the pathogenesis of RA by increasing chemokine production by FLSs via CAP1 in synovial tissue.

Role of exosomes in hepatocellular carcinoma cell mobility alteration.

Exosomes have gained increased research focus due to their key roles as messengers. The components of exosomes include proteins and RNAs that may be horizontally transferred between adjacent or distant cells. Hepatocellular carcinoma (HCC) is among the most malignant types of cancer worldwide, with exosomes implicated to play a crucial role in its regulation; however, the possible function of exosomes in modulating the motile ability of tumor cells and key molecules in HCC remain largely unknown. To investigate the regulatory effect of exosomes on the motile ability of HCC cells, exosomes from the culture medium of different HCC origins (high metastatic MHCC97-H and low metastatic MHCC97-L cells) were isolated for in vitro migration and invasion assays. The results indicated that the motile ability of MHCC97-L cells was significantly increased by pretreatment with MHCC97-H-derived exosomes when compared with MHCC97-L-exosome pretreatment (P<0.05). To further characterize the function of exosomes at the molecular level, protein profiling of exosomes from different cell origins was performed, which identified 129 proteins. Among these, adenylyl cyclase-associated protein 1, a protein implicated in HCC metastasis, was significantly enriched in exosomes from cells with high motile ability (P<0.05). The results of the present study validated the regulatory effect of exosomes on the motile ability of HCC cells. Furthermore, systematic analysis of the protein profiles of exosomes from different origins identified potential factors correlated with HCC metastasis, which may provide a basis for future functional analysis of exosomes regarding their involvement in cancer metastasis and recurrence.

Adenylyl Cyclase-Associated Protein 1 in the Development of Head and Neck Squamous Cell Carcinomas.

We compared the content of adenylyl cyclase-associated protein 1 (CAP1) in the blood and tissues of patients with head and neck squamous cell carcinomas (with and without regional metastases), patients with chronic inflammatory diseases aggravated by laryngeal and laryngopharyngeal dysplasia, and healthy individuals. The data suggest that serum CAP1 concentration correlated with the depth of primary tumor invasion and the presence of regional metastases. In cancer patients, the serum level of CAP1 was lower than in patients with laryngeal and laryngopharyngeal dysplasia, which can be of importance for differential and timely diagnostics of malignant tumors.

The eukaryotic expression,intracellular location and functions of human CAP1 / 西安交通大学学报(医学版)

Objective To construct the recombinant eukaryotic expression plasmids of human adenylyl cyclase-associated protein 1 (CAP1)and to explore its intracellular location and functions.Methods By using Hela cDNA as the template,the cDNAs encoding CAP1 was amplified by PCR and inserted into pCMV-Myc vector to construct the recombinant plasmid.The recombinant plasmid was transfected into 293 cells using lipofectamine 2000.The protein expression and the intracellular location of the inserted gene were confirmed by Western blotting and immunofluorescence,respectively.Scratch-repair experiment was used to detect the cancer cells’ migration ability.Results The recombinant eukaryotic expression plasmid of human CAP1 was successfully constructed and transfected into eukaryote cells.The recombinant plasmid was successfully expressed in eukaryote cells.CAP1 was located in the cytoplasm.The results of scratch-repair experiment showed that the overexpression of CAP1 could significantly inhibit the cells’ migration.Conclusion CAP1 recombinant plasmid was successfully expressed in eukaryotic cells.CAP1 protein was located in the cytoplasm.The overexpression of CAP1 inhibited cell migration. The present study provides important experimental evidence for further study on CAP1.

Expression of cyclase-Associated protein 1 in breast cancer tissues and its clinical significance / 肿瘤

Objective: To investigate the expression of cyclase-Associated protein 1 (CAP1) in breast cancer tissues and its clinical significance. Methods: Overall 93 specimens of breast cancer tissues and the paracancerous tissues were collected. The expressions of CAP1 and Ki-67 in breast cancer tissues and the para-cancerous tissues were detected by immunohistochemistry. The correlations of CAP1 with clinicopathological features and the prognosis were analyzed. Results: The expression levels of CAP1 and Ki-67 in breast cancer tissues were higher than those in the para-cancerous tissues (both P 0.05). There was a positive correlation between CAP1 expression and Ki-67 in breast cancer tissues (r 2 = 0.403, P = 0.002). The differentiation, axillary lymph node status, CAP1 expression and Ki-67 were independent prognostic factors of breast cancer (all P < 0.05). Conclusion: The expression of CAP1 is high in breast cancer tissues. CAP1 may play an important role in proliferation in breast cancer cells.

Relationship between expression of matrix metalloproteinase-9 and adenylyl cyclase-associated protein 1 in chronic obstructive pulmonary disease.

OBJECTIVE: To investigate the relationship between expression of matrix metalloproteinase (MMP)-9 and expression of adenylyl cyclase-associated protein (CAP)-1 in chronic obstructive pulmonary disease (COPD). METHODS: Patients with possible respiratory disease were recruited into the study and divided into a COPD group and a non-COPD group on diagnosis. Pulmonary function tests were performed and serum concentrations of MMP-9 were measured using an enzyme-linked immunosorbent assay. MMP-9 and CAP1 expression were analysed in lung tissue and bronchoalveolar lavage fluid in all available samples using immunohistochemistry and Western blot, respectively. In addition, expression of MMP-9 and CAP1 in vitro was investigated using immunofluorescence. Expression of CAP1 in response to MMP-9 was measured in the human alveolar epithelial cell line HP-AEpiC, using Western blot. RESULTS: A total of 90 patients were included in the study: 52 were in the COPD group and 38 in the non-COPD group. Serum MMP-9 concentrations were significantly higher in the COPD than in the non-COPD group. MMP-9 serum concentrations were negatively correlated with forced expiratory volume in 1 s (FEV1), FEV1 as a percentage of the normal predicted value and the ratio of FEV1 to forced vital capacity, and were positively correlated with residual volume (RV), total lung capacity (TLC) and RV/TLC values. In lung tissue and bronchoalveolar lavage fluid samples, MMP-9 and CAP1 expression were inversely related. This relationship was confirmed in HP-AEpiC cells. High expression of MMP-9 and low expression of CAP1 was demonstrated in the COPD group compared with the non-COPD group. CONCLUSIONS: This study demonstrated an inverse relationship between CAP1 and MMP-9 expression, and high expression of MMP-9 and low expression of CAP1 in those with COPD compared with the non-COPD group. Overexpression of MMP-9 in lung tissue and its interaction with CAP1 is likely to play a major role in airway obstruction in COPD.

Knocking down the expression of adenylate cyclase-associated protein 1 inhibits the proliferation and migration of breast cancer cells.

Adenylate cyclase-associated protein 1 (CAP1) is a conserved protein that was found to be up-regulated in breast cancer and related to the migration of breast cancer. We verified its roles in breast cancer specimens and cell lines. In our results, 71 of 100 specimens of breast cancer showed high levels of CAP1 by immunohistochemistry. Associated with statistical analysis, we saw that CAP1 was related to the grade of breast cancer. In MDA-MB-231, the expression of CAP1 was the highest and by knocking down the expression of CAP1 in MDA-MB-231, its ability for proliferating and migrating apparently decreased and induced changes in morphology, which were related to the arrangement of F-actin. Therefore, CAP1 might be a potential molecular targeted therapy for surgery and immune treatment.

Upregulated expression of CAP1 is associated with tumor migration and metastasis in hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is one of the most common cancers that exhibits high incidences of intrahepatic metastasis and tumor recurrence. Adenylate cyclase-associated protein 1 (CAP1), a protein involved in the regulation of actin filaments, was recently reported to play a role in cell motility and the pathology of pancreatic cancer. In this study, we examined a potential role of CAP1 in HCC progression, and found that CAP1 was overexpressed in HCC specimens compared with adjacent noncancerous liver tissues by Western blot analysis and real-time PCR assay. Further, immunohistochemical analysis in 107 HCC specimens revealed that overexpression of CAP1 was closely correlated only with tumor metastasis, but not with other clinicopathologic parameters. Univariate and multivariate survival analyses showed that CAP1 could be an independent prognostic factor for patients' survival. In addition, immunofluorescent assay demonstrated that CAP1 was colocalized with actin in the leading edge of lamellipodium in HCC cells. Importantly, knocking-down the expression of CAP1 using small interfering RNA (siRNA) targeting CAP1 led to impaired migration of HCC cells. Collectively, our results indicated that upregulated expression of CAP1 might contribute heavily to the metastasis of HCC.