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

Integrated transcriptomic and immunological profiling reveals new diagnostic and prognostic models for cutaneous melanoma

The mortality rate associated with cutaneous melanoma (SKCM) remains alarmingly high, highlighting the urgent need for a deeper understanding of its molecular underpinnings. In our study, we leveraged bulk transcriptome sequencing data from the SKCM cohort available in public databases such as TCGA and GEO. We utilized distinct datasets for training and validation purposes and also incorporated mutation and clinical data from TCGA, along with single-cell sequencing data from GEO. Through dimensionality reduction, we annotated cell subtypes within the single-cell data and analyzed the expression of tumor-related pathways across these subtypes. We identified differentially expressed genes (DEGs) in the training set, which were further refined using the Least Absolute Shrinkage and Selection Operator (LASSO) machine learning algorithm, employing tenfold cross-validation. This enabled the construction of a prognostic model, whose diagnostic efficacy we subsequently validated. We conducted Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses on the DEGs, and performed immunological profiling on two risk groups to elucidate the relationship between model genes and the immune responses relevant to SKCM diagnosis, treatment, and prognosis. We also knocked down the GMR6 expression level in the melanoma cells and verified its effect on cancer through multiple experiments. The results indicate that the GMR6 gene plays a role in promoting the proliferation, invasion, and migration of cancer cells in human melanoma. Our findings offer novel insights and a theoretical framework that could enhance prognosis, treatment, and drug development strategies for SKCM, potentially leading to more precise therapeutic interventions.

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.

OSgc: A Web Portal to Assess the Performance of Prognostic Biomarkers in Gastric Cancer

Evaluating the prognostic value of genes of interest in different populations of gastric cancer (GC) is difficult and time-consuming for basic and translational researchers even though many datasets are available in public dataset depositories. In the current study, we developed a robust web-based portal called OSgc (Online consensus Survival analysis of gastric cancer) that enables easy and swift verification of known and novel biomarker candidates in GC. OSgc is composed of gene expression profiling data and clinical follow-up information of 1,824 clinical GC cases, which are collected from 7 public independent datasets derived from Gene Expression Omnibus (GEO) and The Cancer Genome Atlas (TCGA). By OSgc, users input the official gene symbol and will promptly retrieve the Kaplan-Meier survival plot with hazard ratio (HR) and log rank p value on the output webpage, by which users could assess the prognostic value of interesting genes for GC patients. Five survival end points containing overall survival, progression-free survival, progression-free interval, relapse-free survival, and disease-free survival could be measured in OSgc. OSgc can greatly help cancer biologists and clinicians to explore the effect of gene expression on patient survival. OSgc is freely available without restrictions at http://bioinfo.henu.edu.cn/GC/GCList.jsp.

Characterization of a Peptide Antibody Specific to the Adenylyl Cyclase-Associated Protein of Acanthamoeba castellanii

Acanthamoeba keratitis (AK) is a rare infectious disease and accurate diagnosis has remained arduous as clinical manifestations of AK were similar to keratitis of viral, bacterial, or fungal origins. In this study, we described the production of a polyclonal peptide antibody against the adenylyl cyclase-associated protein (ACAP) of A. castellanii, and evaluated its differential diagnostic potential. Enzyme-linked immunosorbent assay revealed high titers of A. castellanii-specific IgG and IgA antibodies being present in low dilutions of immunized rabbit serum. Western blot analysis revealed that the ACAP antibody specifically interacted with A. castellanii, while not interacting with human corneal epithelial (HCE) cells and other causes of keratitis such as Fusarium solani, Pseudomonas aeruginosa, and Staphylococcus aureus. Immunocytochemistry (ICC) results confirmed the specific detection of trophozoites and cysts of A. castellanii co-cultured with HCE cells. The ACAP antibody also specifically interacted with the trophozoites and cysts of 5 other Acanthamoeba species. These results indicate that the ACAP antibody of A. castellanii can specifically detect multiple AK-causing members belonging to the genus Acanthamoeba and may be useful for differentially diagnosing Acanthamoeba infections.

Helicobacter pylori Infection-Related Long Non-Coding RNA Signatures Predict the Prognostic Status for Gastric Cancer Patients

Background

Helicobacter pylori (H. pylori) is a type I biological carcinogen, which may cause about 75% of the total incidence of gastric cancer worldwide. H. pylori infection can induce and activate the cancer-promoting signaling pathway and affect the occurrence and outcome of gastric cancer through controlling the regulatory functions of long non-coding RNAs (lncRNAs). However, we have no understanding of the prognostic worth of lncRNAs for gastric cancer patients infected with H. pylori.

Method

We screened differentially expressed lncRNAs using DESeq2 method among TCGA database. And we built the H. pylori infection-related lncRNAs regulatory patterns. Then, we constructed H. pylori infection-based lncRNAs prognostic signatures for gastric cancer patients together with H. pylori infection, via uni-variable and multi-variable COX regression analyses. Based on receiver operator characteristic curve (ROC) analysis, we evaluated the prediction effectiveness for this model.

Results

We identified 115 H. pylori infection-related genes were differentially expressed among H. pylori-infected gastric cancer tissues versus gastric cancer tissues. Functional enrichment analysis implies that H. pylori infection might interfere with the immune-related pathways among gastric cancer tissues. Then, we built H. pylori infection-related dys-regulated lncRNA regulatory networks. We also identified 13 differentially expressed lncRNAs were associated with prognosis for gastric cancer patients together with H. pylori infection. Kaplan-Meier analysis demonstrated that the lncRNA signatures were correlated with the poor prognosis. What is more, the AUC of the lncRNA signatures was 0.712. Also, this prognostic prediction model was superior to the traditional clinical characters.

Conclusion

We successfully constructed a H. pylori-related lncRNA risk signature and nomogram associated with H. pylori-infected gastric cancer patients prognosis, and the signature and nomogram can predict the prognosis of these patients.

VSNL1 Promotes Gastric Cancer Cell Proliferation and Migration by Regulating P2X3/P2Y2 Receptors and Is a Clinical Indicator of Poor Prognosis in Gastric Cancer Patients

Purpose

The aim of this study was to investigate the role of Visinin Like 1 (VSNL1) in the proliferation and migration of gastric cancer (GC) cells as well as its clinical prognostic significance.

Methods

To this end, we evaluated VSNL1 expression in GC tissues and cell lines by real-time PCR and immunohistochemistry. To further explore the effects of VSNL1, a lentiviral vector expressing a short hairpin RNA (shRNA) against VSNL1 was constructed and transduced into the GC cell lines BGC-823 and SGC-7901. The interference efficiency of VSNL1-shRNA was determined by western blot. The effects of VSNL1 on the migration and invasion of GC cells as well as the expression of P2X3/P2Y2 were explored using MTS, colony formation, migration, and western blot assays.

Results

VSNL1 mRNA and protein levels were increased in GC tissues and cell lines. Furthermore, VSNL1 expression was positively correlated with Lauren's classification, lymph node metastasis, distant metastasis, TNM stage, and prognosis. VSNL1 expression was inversely correlated with the 5-year survival rate of GC patients. VSNL1 expression was markedly reduced in cells transduced with lentivirus expressing shRNA against VSNL1, and inhibiting VSNL1 expression significantly suppressed cell growth, migration, and colony formation and reduced the expression of P2X3/P2Y2.

Conclusion

VSNL1 may promote the proliferation and migration of GC cells by regulating P2X3 and P2Y2 expression. VSNL1 plays important roles in GC development and metastasis and may be correlated with patient prognosis.

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.

New Blood Biomarkers for the Diagnosis of AFP-Negative Hepatocellular Carcinoma

An early diagnosis of hepatocellular carcinoma (HCC) followed by effective treatment is currently critical for improving the prognosis and reducing the associated economic burden. Alpha-fetoprotein (AFP) is the most widely used biomarker for HCC diagnosis. Based on elevated serum AFP levels as well as typical imaging features, AFP-positive HCC (APHC) can be easily diagnosed, but AFP-negative HCC (ANHC) is not easily detected due to lack of ideal biomarkers and thus mainly reliance on imaging. Imaging for the diagnosis of ANHC is probably insufficient in sensitivity and/or specificity because most ANHC tumors are small and early-stage HCC, and it is involved in sophisticated techniques and high costs. Moreover, ANHC accounts for nearly half of HCC and exhibits a better prognosis compared with APHC. Therefore, the diagnosis of ANHC in clinical practice has been a critical issue for the early treatment and prognosis improvement of HCC. In recent years, tremendous efforts have been made to discover new biomarkers complementary to AFP for HCC diagnosis. In this review, we systematically review and discuss the recent advances of blood biomarkers for HCC diagnosis, including DNA biomarkers, RNA biomarkers, protein biomarkers, and conventional laboratory metrics, focusing on their diagnostic evaluation alone and in combination, in particular on their diagnostic performance for ANHC.

Overexpression of FNDC1 Relates to Poor Prognosis and Its Knockdown Impairs Cell Invasion and Migration in Gastric Cancer

The distribution and content of fibronectin is closely related to the occurrence and development of tumors. Fibronectin is widely involved in cell migration, adhesion, proliferation, hemostasis, and tissue repair. Fibronectin type III domain containing 1, as a primary component of the structural domain of fibronectin, is closely related to the occurrence of some cancers. However, the molecular mechanism of fibronectin type III domain containing 1 in gastric cancer has not been elaborated. In this study, we analyzed the expression and prognosis of fibronectin type III domain containing 1 by collecting data from Oncomine and GEPIA database. The expression of fibronectin type III domain containing 1 in gastric cancer cells was detected by quantitative real-time polymerase chain reaction in vitro. After knockdown of fibronectin type III domain containing 1 by small interfering RNA, the proliferation, invasion, and migration of AGS (human gastric adenocarcinoma cell line) cells and the function of epithelial–mesenchymal transition were measured by Cell Counting Kit-8, colony formation, transwell, and Western blot. The results showed that fibronectin type III domain containing 1 was highly expressed in gastric cancer tissues and its overexpression was significantly correlated with the prognosis of gastric cancer. In vitro, experiments revealed that knockdown of fibronectin type III domain containing 1 could inhibit the proliferation, migration, and invasion of gastric cancer cells, possibly by changing the epithelial–mesenchymal transition pathway. The findings elaborated the biological role of fibronectin type III domain containing 1 in gastric cancer and potential mechanism of action, possibly providing a new insight for future clinical diagnosis or even molecular therapy.

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.

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.

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

OBJECTIVE

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.

METHODS

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.

RESULTS

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).

CONCLUSIONS

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.