CAP1 is overexpressed in human epithelial ovarian cancer and promotes cell proliferation

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.

The expression of FLNA and CLU in PBMCs as a novel screening marker for hepatocellular carcinoma

Early detection improves survival and increases curative probability in hepatocellular carcinoma (HCC). Peripheral blood mononuclear cells (PBMCs) can provide an inexpensive, less-invasive and highly accurate method. The objective of this study is to find the potential marker for HCC screening, utilizing gene expression of the PBMCs. Data from the NCBI GEO database of gene expression in HCC patients and healthy donor's PBMCs was collected. As a result, GSE 49515 and GSE 58208 were found. Using both, a statistical significance test was conducted in each gene expression of each data set which resulted in 187 genes. We randomized three selected genes (FLNA, CAP1, and CLU) from the significant p-value group (p-values < 0.001). Then, a total of 76 healthy donors, 153 HCC, 20 hepatic fibrosis, 20 non-alcoholic fatty liver were collected. Quantitative RT-PCR (qRT-PCR) was performed in cDNA from all blood samples from the qRT-PCR, The Cycle threshold (Ct) value of FLNA, CLU, CAP1 of HCC group (28.47 ± 4.43, 28.01 ± 3.75, 29.64 ± 3.90) were lower than healthy group (34.23 ± 3.54, 32.90 ± 4.15, 32.18 ± 5.02) (p-values < 0.0001). The accuracy, sensitivity and specificity of these genes as a screening tool were: FLNA (80.8%, 88.0%, 65.8%), CLU (63.4%, 93.3%, 31.3%), CAP1 (67.2%, 83.3%, 39.1%). The tests were performed in two and three gene combinations. Results demonstrated high accuracy of 86.2%, sensitivity of 85% and specificity of 88.4% in the FLNA and CLU combination. Furthermore, after analyzed using hepatic fibrosis and non-alcoholic fatty liver as a control, the FLNA and CLU combination is shown to have accuracy of 76.9%, sensitivity of 77.6% and specificity of 75%. Also, we founded that our gene combination performs better than the current gold standard for HCC screening. We concluded that FLNA and CLU combination have high potential for being HCC novel markers. Combined with current tumor markers, further research of the gene’s expression might help identify more potential markers and improve diagnosis methods.

Research Progress in Prognostic Factors and Biomarkers of Ovarian Cancer

Ovarian cancer is a serious threat to women's health; its early diagnosis rate is low and prone to metastasis and recurrence. The current conventional treatment for ovarian cancer is a combination of platinum and paclitaxel chemotherapy based on surgery. The recurrence and progression of ovarian cancer with poor prognosis is a major challenge in treatment. With rapid advances in technology, understanding of the molecular pathways involved in ovarian cancer recurrence and progression has increased, biomarker-guided treatment options can greatly improve the prognosis of patients. This review systematically discusses and summarizes existing and new information on prognostic factors and biomarkers of ovarian cancer, which is expected to improve the clinical management of patients and lead to effective personalized treatment.

CAPt'n of Actin Dynamics: Recent Advances in the Molecular, Developmental and Physiological Functions of Cyclase-Associated Protein (CAP)

Cyclase-associated protein (CAP) has been discovered three decades ago in budding yeast as a protein that associates with the cyclic adenosine monophosphate (cAMP)-producing adenylyl cyclase and that suppresses a hyperactive RAS2 variant. Since that time, CAP has been identified in all eukaryotic species examined and it became evident that the activity in RAS-cAMP signaling is restricted to a limited number of species. Instead, its actin binding activity is conserved among eukaryotes and actin cytoskeleton regulation emerged as its primary function. However, for many years, the molecular functions as well as the developmental and physiological relevance of CAP remained unknown. In the present article, we will compile important recent progress on its molecular functions that identified CAP as a novel key regulator of actin dynamics, i.e., the spatiotemporally controlled assembly and disassembly of actin filaments (F-actin). These studies unraveled a cooperation with ADF/Cofilin and Twinfilin in F-actin disassembly, a nucleotide exchange activity on globular actin monomers (G-actin) that is required for F-actin assembly and an inhibitory function towards the F-actin assembly factor INF2. Moreover, by focusing on selected model organisms, we will review current literature on its developmental and physiological functions, and we will present studies implicating CAP in human pathologies. Together, this review article summarizes and discusses recent achievements in understanding the molecular, developmental and physiological functions of CAP, which led this protein emerge as a novel CAPt'n of actin dynamics.

Effects of tumor-specific CAP1 expression and body constitution on clinical outcomes in patients with early breast cancer

Background

Obesity induces molecular changes that may favor tumor progression and metastatic spread, leading to impaired survival outcomes in breast cancer. Adenylate cyclase-associated protein 1 (CAP1), an actin regulatory protein and functional receptor for the obesity-associated adipokine resistin, has been implicated with inferior cancer prognosis. Here, the objective was to investigate the interplay between body composition and CAP1 tumor expression regarding breast cancer outcome through long-term survival analyses.

Methods

Among 718 women with primary invasive breast cancer within the large population-based prospective Malmö Diet and Cancer Study, tumor-specific CAP1 levels were assessed following thorough antibody validation and immunohistochemical staining of tumor tissue microarrays. Antibody specificity and functional application validity were determined by CAP1 gene silencing, qRT-PCR, Western immunoblotting, and cell microarray immunostaining. Kaplan-Meier and multivariable Cox proportional hazard models were used to assess survival differences in terms of breast cancer-specific survival (BCSS) and overall survival (OS) according to body composition and CAP1 expression.

Results

Study participants were followed for up to 25 years (median 10.9 years), during which 239 deaths were observed. Patients with low CAP1 tumor expression were older at diagnosis, displayed anthropometric measurements indicating a higher adiposity status (wider waist and hip, higher body mass index and body fat percentage), and were more prone to have unfavorable tumor characteristics (higher histological grade, higher Ki67, and estrogen receptor (ER) negativity). Overall, patients with CAP1-low tumors had impaired BCSS (adjusted hazard ratio: HR_adj = 0.52, 95% CI 0.31–0.88) and OS (HR_adj = 0.64, 95% CI 0.44–0.92) compared with patients having high CAP1 tumor expression. Further, analyses stratified according to different anthropometric measures or ER status showed that the CAP1-associated survival outcomes were most pronounced among patients with low adiposity status or ER-positive disease.

Conclusions

Low CAP1 tumor expression was associated with higher body fatness and worse survival outcomes in breast cancer patients with effect modification by adiposity and ER status. CAP1 could be a novel marker for poorer survival outcome in leaner or ER-positive breast cancer patients, highlighting the need for considering body constitution in clinical decision making.

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

Background

Gliomas 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 methods

CAP2 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.

Results

Our 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).

Conclusion

CAP2 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.

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.

Oligomerization Affects the Ability of Human Cyclase-Associated Proteins 1 and 2 to Promote Actin Severing by Cofilins

Actin-depolymerizing factor (ADF)/cofilins accelerate actin turnover by severing aged actin filaments and promoting the dissociation of actin subunits. In the cell, ADF/cofilins are assisted by other proteins, among which cyclase-associated proteins 1 and 2 (CAP1,2) are particularly important. The N-terminal half of CAP has been shown to promote actin filament dynamics by enhancing ADF-/cofilin-mediated actin severing, while the central and C-terminal domains are involved in recharging the depolymerized ADP-G-actin/cofilin complexes with ATP and profilin. We analyzed the ability of the N-terminal fragments of human CAP1 and CAP2 to assist human isoforms of "muscle" (CFL2) and "non-muscle" (CFL1) cofilins in accelerating actin dynamics. By conducting bulk actin depolymerization assays and monitoring single-filament severing by total internal reflection fluorescence (TIRF) microscopy, we found that the N-terminal domains of both isoforms enhanced cofilin-mediated severing and depolymerization at similar rates. According to our analytical sedimentation and native mass spectrometry data, the N-terminal recombinant fragments of both human CAP isoforms form tetramers. Replacement of the original oligomerization domain of CAPs with artificial coiled-coil sequences of known oligomerization patterns showed that the activity of the proteins is directly proportional to the stoichiometry of their oligomerization; i.e., tetramers and trimers are more potent than dimers, which are more effective than monomers. Along with higher binding affinities of the higher-order oligomers to actin, this observation suggests that the mechanism of actin severing and depolymerization involves simultaneous or consequent and coordinated binding of more than one N-CAP domain to F-actin/cofilin complexes.

Adenylyl cyclase‑associated protein 1‑targeted nanoparticles as a novel strategy for the treatment of metastatic non‑small cell lung cancer

Non‑small cell lung cancer (NSCLC) is one of the most fatal cancers worldwide. Adenylyl cyclase‑associated protein 1 (CAP1) belongs to a family of cyclase‑associated proteins that are involved in the development of cancerous tumors. A previous study by our group confirmed the association between CAP1, lung cancer and the metastasis of cancer cells. In the present study, poly(lactic‑polyglycolic acid; PLGA)/CAP1‑small interfering (si)RNA nanoparticles were prepared and delivered into A549 cells. The performance of PLGA/siCAP1‑siRNA nanoparticles for siRNA delivery was measured based on the results of migration assay and animal experiments. The multifunctional nanoparticles were determined to be capable of inhibiting CAP1 expression, which reduced NSCLC metastasis in vitro and in vivo. Therefore, the findings of the current study highlighted the potential use of PLGA/siCAP1‑siRNA nanoparticles for the treatment of NSCLC metastasis.

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.

The Cytoskeletal Protein Cyclase-Associated Protein 1 (CAP1) in Breast Cancer: Context-Dependent Roles in Both the Invasiveness and Proliferation of Cancer Cells and Underlying Cell Signals

As a conserved actin-regulating protein, CAP (adenylyl Cyclase-Associated Protein) functions to facilitate the rearrangement of the actin cytoskeleton. The ubiquitously expressed isoform CAP1 drives mammalian cell migration, and accordingly, most studies on the involvement of CAP1 in human cancers have largely been based on the rationale that up-regulated CAP1 will stimulate cancer cell migration and invasiveness. While findings from some studies reported so far support this case, lines of evidence largely from our recent studies point to a more complex and profound role for CAP1 in the invasiveness of cancer cells, where the potential activation of cell adhesion signaling is believed to play a key role. Moreover, CAP1 was also found to control proliferation in breast cancer cells, through the regulation of ERK (External signal-Regulated Kinase). Alterations in the activities of FAK (Focal Adhesion Kinase) and ERK from CAP1 depletion that are consistent to the opposite adhesion and proliferation phenotypes were detected in the metastatic and non-metastatic breast cancer cells. In this review, we begin with the overview of the literature on CAP, by highlighting the molecular functions of mammalian CAP1 in regulating the actin cytoskeleton and cell adhesion. We will next discuss the role of the FAK/ERK axis, and possibly Rap1, in mediating CAP1 signals to control breast cancer cell adhesion, invasiveness, and proliferation, largely based on our latest findings. Finally, we will discuss the relevance of these novel mechanistic insights to ultimately realizing the translational potential of CAP1 in targeted therapeutics for breast cancer.

High Ki-67 expression is significantly associated with poor prognosis of ovarian cancer patients: evidence from a meta-analysis

OBJECTIVE

The prognostic significance of Ki-67 expression in patients with ovarian cancer was controversial in various studies. Therefore, we carried out a meta-analysis to determine the prognostic significance of Ki-67 in ovarian cancer patients.

METHODS

We searched PubMed, Cochrane Library, EMBASE, Web of Knowledge, China National Knowledge Infrastructure database and WanFang digital database for eligible studies from January 1, 1990 to June 1, 2017. The pooled hazard ratios and 95% confidence intervals were calculated to assess the prognostic significance of Ki-67 expression for overall survival in ovarian cancer patients.

RESULTS

Finally, 38 eligible studies and 5004 ovarian cancer patients were included in the current study. The pooled hazard ratio was 1.35 (95% confidence interval 1.24-1.46, P = 0.001) for overall survival in ovarian cancer patients. The funnel plot bias was obviously asymmetrical and Egger's test also detected significant publication bias (P = 0.001). The Contour-enhanced funnel plot with trim-and-fill method supplemented 11 dummy studies to balance the funnel plot and nine new supplementary studies were in area with statistical significance. Sensitivity analysis and cumulative meta-analysis further demonstrated that the association between high Ki-67 expression and poor overall survival of ovarian cancer patients was stable and reliable.

CONCLUSIONS

High Ki-67 expression is significantly related to poor overall survival and may serve as a prognostic biomarker for ovarian cancer patients.

Phosphorylation of the Cytoskeletal Protein CAP1 Regulates Non-Small Cell Lung Cancer Survival and Proliferation by GSK3β

Adenylate cyclase-associated protein 1 (CAP1) is an evolutionarily conserved protein that regulates actin dynamics. Our previous study indicates that CAP1 is overexpressed in NSCLC tissues and correlated with poor clinical outcomes. Further establishing the role and dissecting underlying mechanisms are imperative before targeting CAP1 can become a possibility for cancer treatment. Here we report our findings that knockdown of CAP1 inhibited cell proliferation and induced apoptosis in vitro and in vivo. Moreover, phosphor mutants of CAP1 at the S307/S309 regulatory site had compromised rescue effects for both the invasiveness and the proliferation in CAP1-knockdown cells and GSK3β kinase inhibitor LiCl inhibited cell phosphorylation site S307/S309 by up-regulating the expression of p53, BAK, BAD and cleaved PARP induced ROS production, decreased lung cancer cell viability, adhesion, proliferation, migration and invasion, and induction of apoptosis. These novel mechanistic insights may ultimately open up avenues for strategies targeting CAP1 in the treatment of lung cancer, tailored for specific types of the highly diverse disease.

Adenylyl Cyclase-Associated Protein 1: Structure, Regulation, and Participation in Cellular Processes

This review summarizes information available to date about the structural organization, regulation of functional activity of adenylyl cyclase-associated protein 1 (CAP1), and its participation in cellular processes. Numerous data are generalized on the role of CAP1 in the regulation of actin cytoskeleton and its interactions with many actin-binding proteins. Attention is drawn to the similarity of the structure of CAP1 and its contribution to the remodeling of actin filaments in prokaryotes and eukaryotes, as well as to the difference in the interaction of CAP1 with adenylyl cyclase in these cells. In addition, we discuss the participation of CAP1 in various pathological processes.

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 β-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 β-sheet domain. The binding was stabilized by the lipid insertion into the β-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.

Association of RETN and CAP1 SNPs, Expression and Serum Resistin Levels with Breast Cancer in Mexican Women

BACKGROUND

Breast cancer is the most common cancer in women worldwide. Approximately 70% of female breast cancer patients have a body mass index (BMI) >25. In obesity, adipose tissue secretes additional resistin, which prompts a proinflammatory effect through its action on adenylate cyclase-associated protein 1 (CAP1). Several studies have associated the RETN gene single nucleotide polymorphism (SNP) rs1862513 (-420C<G) with serum resistin levels and breast cancer. The CAP1 gene SNP rs35749351 (missense, Arg294His), located in the extracellular domain, has not previously been studied in cancer. These two SNPs, the mRNA expression levels of the two alleles for each of the cognate genes, and the serum resistin levels were compared between patients and controls to determine their association with breast cancer in Mexican women in this study.

MATERIALS AND METHODS

This study included 308 controls and 100 female patients with breast cancer. SNPs were detected by PCR-RFLP from DNA isolated from peripheral blood. Gene expression was performed with hydrolysis probes in tumor tissue. Resistin levels were quantified from serum samples by ELISA.

RESULTS

The RETN rs1862513CG/GG and CAP1 rs35749351GA/AA genotypes were associated with 1.61 and 2.193-fold increased risks of breast cancer, respectively, compared with the CC and GG genotypes. Similarly, carriers of the G allele of rs1862513 and the A allele of rs35749351, had 1.51 and 2.217-fold increased risks of breast cancer compared with the C and G alleles, respectively. The rs1862513GG/rs35749351AA genotype combination increased breast cancer risk by twofold. Serum resistin levels in postmenopausal breast cancer women were higher compared with postmenopausal controls. Tissue CAP1 expression showed differences with regard to molecular subtypes and metastases.

CONCLUSION

The RETN and CAP1 polymorphisms and gene expression may be potential biomarkers for breast cancer risk.

"Stealth dissemination" of macrophage-tumor cell fusions cultured from blood of patients with pancreatic ductal adenocarcinoma

Here we describe isolation and characterization of macrophage-tumor cell fusions (MTFs) from the blood of pancreatic ductal adenocarcinoma (PDAC) patients. The MTFs were generally aneuploidy, and immunophenotypic characterizations showed that the MTFs express markers characteristic of PDAC and stem cells, as well as M2-polarized macrophages. Single cell RNASeq analyses showed that the MTFs express many transcripts implicated in cancer progression, LINE1 retrotransposons, and very high levels of several long non-coding transcripts involved in metastasis (such as MALAT1). When cultured MTFs were transplanted orthotopically into mouse pancreas, they grew as obvious well-differentiated islands of cells, but they also disseminated widely throughout multiple tissues in "stealth" fashion. They were found distributed throughout multiple organs at 4, 8, or 12 weeks after transplantation (including liver, spleen, lung), occurring as single cells or small groups of cells, without formation of obvious tumors or any apparent progression over the 4 to 12 week period. We suggest that MTFs form continually during PDAC development, and that they disseminate early in cancer progression, forming "niches" at distant sites for subsequent colonization by metastasis-initiating cells.

Association of adenylate cyclase-associated protein 1 with coronary artery disease

BACKGROUND

Adenylate cyclase-associated protein 1 (CAP1) is a recently identified receptor for human resistin. As resistin has been related to CAD development and progression and CAP1 has never been evaluated in CAD, the aim of this study was to determine its peripheral blood mononuclear cells (PBMCs) mRNA in patients with CAD, and resistin plasma concentration, PBMCs resistin and CD36 mRNA, considering resistiǹs ability to stimulate CD36 expression in vitro.

MATERIALS AND METHODS

This case-controlled study included 27 healthy subjects (CG) and 66 patients requiring coronary angiography. Of the latter, 42 had nonsignificant CAD whereas 24 had significant CAD. Circulating resistin was measured by ELISA; PBMCs CAP1, resistin and CD36 mRNA were determined by real-time PCR.

RESULTS

Patients with significant as well as patients with nonsignificant CAD had significantly higher resistin concentrations compared to the CG (P < 0·001; P = 0·003). Resistin mRNA did not show significant difference between the investigated groups. CAP1 and CD36 mRNA were significantly higher in significant CAD (P < 0·001; P < 0·001, respectively) and nonsignificant CAD (P < 0·001; P < 0·001, respectively) compared to the CG; significant CAD showed significantly higher CD36 mRNA (P = 0·040) compared to the nonsignificant CAD group. Multiple linear regression analysis identified Tg and CD36 mRNA as independent predictors of CAP1 (R²  = 0·402; adjR²  = 0·376).

CONCLUSION

Significant up-regulation of PBMCs CAP1, CD36 mRNA and plasma resistin found in significant CAD, as well as in nonsignificant CAD compared to CG, indicates that resistin could be able to exert its effects stronger on cells with up-regulated CAP1 mRNA thus contributing atherosclerosis development.

Adiponectin and Intelectin-1: Important Adipokine Players in Obesity-Related Colorectal Carcinogenesis

Overweight is believed to be associated with colorectal cancer risk. Adipose tissue is loose connective tissue composed of adipocytes. It is now recognized as a major endocrine organ, secreting humoral factors collectively called adipokines. Aberrant hormonal systems consisting of modulated adipokines and their receptors are thought to play a role in colorectal carcinogenesis and cancer progression in obese conditions. However, it is still unclear whether and how each adipokine relates to colorectal carcinogenesis. Notably, a couple of molecules that were initially proposed to be obesity-related adipokines were disqualified by subsequent studies. The adipokines, adiponectin, and intelectin-1 (also known as omentin-1), whose levels are decreased in obesity, act as tumor suppressor factors in various cancers. Numerous studies have demonstrated a link between the insufficient expression and function of adiponectin and its receptor, T-cadherin, in colorectal carcinogenesis. Moreover, our recent study indicated that loss of TMEM207, which is critical for the proper processing of intelectin-1 in the colon mucosa, leads to insufficient intelectin-1 production, thus participating in colorectal carcinogenesis. Here, we discuss the recent understanding of the role of adipokines in colorectal carcinogenesis and subsequently describe the potent tumor suppressor roles of intelectin-1 and TMEM207 in colorectal cancer.

Adiponectin and Intelectin-1: Important Adipokine Players in Obesity-Related Colorectal Carcinogenesis

Overweight is believed to be associated with colorectal cancer risk. Adipose tissue is loose connective tissue composed of adipocytes. It is now recognized as a major endocrine organ, secreting humoral factors collectively called adipokines. Aberrant hormonal systems consisting of modulated adipokines and their receptors are thought to play a role in colorectal carcinogenesis and cancer progression in obese conditions. However, it is still unclear whether and how each adipokine relates to colorectal carcinogenesis. Notably, a couple of molecules that were initially proposed to be obesity-related adipokines were disqualified by subsequent studies. The adipokines, adiponectin, and intelectin-1 (also known as omentin-1), whose levels are decreased in obesity, act as tumor suppressor factors in various cancers. Numerous studies have demonstrated a link between the insufficient expression and function of adiponectin and its receptor, T-cadherin, in colorectal carcinogenesis. Moreover, our recent study indicated that loss of TMEM207, which is critical for the proper processing of intelectin-1 in the colon mucosa, leads to insufficient intelectin-1 production, thus participating in colorectal carcinogenesis. Here, we discuss the recent understanding of the role of adipokines in colorectal carcinogenesis and subsequently describe the potent tumor suppressor roles of intelectin-1 and TMEM207 in colorectal cancer.

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

Cyclase-associated protein 2 (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 reaction and western blotting in 10 paired 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 immunohistochemical analysis. 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 10 paired 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.

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.

Increased Expression of CAP2 Indicates Poor Prognosis in Hepatocellular Carcinoma

CAP2 has been suggested as a potential diagnostic biomarker for early hepatocellular carcinoma (HCC). However, its prognostic significance in HCC remains unclear. Here, we show that CAP2 expression is much higher in HCC tissues than that in paracarcinoma tissues, at both mRNA and protein levels. Data of immunohistochemistry (IHC) revealed that CAP2 was markedly up-regulated in 77.3% of HCC cases. High CAP2 expression, defined by the median score of IHC, was present in 53.3% of the patients. Kaplan-Meier analysis indicated that high CAP2 expression was associated with poor overall survival (P < .0001), disease-free survival (P = .013) and recurrence probability (P = .004) in a training cohort of 312 HCC patients. The prognostic implication of CAP2 in HCC was further confirmed in a validation cohort of 208 HCC patients and by stratified survival analysis. Multiple Cox regression analysis indicated CAP2 as an independent predictor for overall survival (hazard ratio (HR) = 1.615, 95% confidence interval: 1.345-1.938, P < .001). Collectively, we conclude that CAP2 is increased in HCC and is a novel unfavorable biomarker for prognostic prediction for patients with this deadly disease.

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.