CLCA4 inhibits cell proliferation and invasion of hepatocellular carcinoma by suppressing epithelial-mesenchymal transition via PI3K/AKT signaling

RNA-Seq transcriptome profiling of Nile rat livers reveals novel insights on the anti-diabetic mechanisms of Water-Soluble Palm Fruit Extract

Water-Soluble Palm Fruit Extract (WSPFE) has been shown to confer anti-diabetic effects in the Nile rat (NR) (Arvicanthis niloticus). Liquid and powder WSPFE both deterred diabetes onset in NRs fed a high-carbohydrate (hiCHO) diet, but the liquid form provided better protection. In this study, NRs were fed either a hiCHO diet or the same diet added with liquid or powder WSPFE. Following feeding of the diets for 8 weeks, random blood glucose levels were measured to categorize NRs as either diabetes-resistant or diabetes-susceptible, based on a cut-off value of 75 mg/dL. Livers were then obtained for Illumina HiSeq 4000 paired end RNA-sequencing (RNA-Seq) and the data were mapped to the reference genome. Consistent with physiological and biochemical parameters, the gene expression data obtained indicated that WSPFE was associated with protection against diabetes. Among hepatic genes upregulated by WSPFE versus controls, were genes related to insulin-like growth factor binding protein, leptin receptor, and processes of hepatic metabolism maintenance, while those downregulated were related to antigen binding, immunoglobulin receptor, inflammation- and cancer-related processes. WSPFE supplementation thus helped inhibit diabetes progression in NRs by increasing insulin sensitivity and reducing both the inflammatory effects of a hiCHO diet and the related DNA-damage compensatory mechanisms contributing to liver disease progression. In addition, the genetic permissiveness of susceptible NRs to develop diabetes was potentially associated with dysregulated compensatory mechanisms involving insulin signaling and oxidative stress over time. Further studies on other NR organs associated with diabetes and its complications are warranted.

Weighted gene co-expression network analysis for hub genes in colorectal cancer

BACKGROUND

This study is designed to explore hub genes participating in colorectal cancer (CRC) development through weighted gene co-expression network analysis (WGCNA).

METHODS

Expression profiles of CRC and normal samples were retrieved from the Gene Expression Omnibus (GEO) and the Cancer Genome Atlas (TCGA), and were subjected to WGCNA to filter differentially expressed genes with significant association with CRC. Functional enrichment analysis and protein-protein interaction (PPI) analysis were carried out to filter the candidate genes, further and survival analysis was performed for the candidate genes to obtain potential regulatory hub genes in CRC. Expression analysis was conducted for the candidate genes and a multifactor model was established.

RESULTS

After differential analysis and WGCNA, 289 candidate genes were filtered from the GEO and TCGA. Further functional enrichment analysis demonstrated possible regulatory pathways and functions. PPI analysis filtered 15 hub genes and survival analysis indicated a significant correlation of CLCA1, CLCA4, and CPT1A with prognosis of patients with CRC. The multifactor Cox risk model established based on the three genes revealed that if the three genes were a gene set, they had well predictive capacity for the prognosis of patients with CRC.

CONCLUSIONS

CLCA1, CLCA4, and CPT1A express at low levels in CRC and function as core anti-tumor genes. As a gene set, they can predict prognosis well.

Regulation of Cellular Signaling with an Aptamer Inhibitor to Impede Cancer Metastasis

Tumor invasion and metastasis are the main causes of tumor progression and are the leading causes of death among cancer patients. In the present study, we propose a strategy to regulate cellular signaling with a tumor metastasis-relevant cytoskeleton-associated protein 4 (CKAP4) specific aptamer for the achievement of tumor metastasis inhibition. The designed aptamer could specifically bind to CKAP4 in the cell membranes and cytoplasm to block the internalization and recycling of α5β1 integrin, resulting in the disruption of the fibronectin-dependent cell adhesion and the weakening of the cell traction force. Moreover, the aptamer is able to impede the interaction between CKAP4 and Dickkopf1 (DKK1) to further block the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT) signaling pathway, which subsequently reduces AKT phosphorylation and inhibits the reorganization of the actin cytoskeleton in cell migration. The synergetic function of the designed aptamer in inhibiting cancer cell adhesion and blocking the PI3K signaling pathway enables efficient tumor cell metastasis suppression. The aptamer with specific targeting ability in regulating cellular signaling paves the way for cancer treatment and further provides a guiding ideology for inhibiting tumor metastasis.

Approach for Elucidating the Molecular Mechanism of Epithelial to Mesenchymal Transition in Fibrosis of Asthmatic Airway Remodeling Focusing on Cl- Channels

Airway remodeling caused by asthma is characterized by structural changes of subepithelial fibrosis, goblet cell metaplasia, submucosal gland hyperplasia, smooth muscle cell hyperplasia, and angiogenesis, leading to symptoms such as dyspnea, which cause marked quality of life deterioration. In particular, fibrosis exacerbated by asthma progression is reportedly mediated by epithelial-mesenchymal transition (EMT). It is well known that the molecular mechanism of EMT in fibrosis of asthmatic airway remodeling is closely associated with several signaling pathways, including the TGF-β1/Smad, TGF-β1/non-Smad, and Wnt/β-catenin signaling pathways. However, the molecular mechanism of EMT in fibrosis of asthmatic airway remodeling has not yet been fully clarified. Given that Cl- transport through Cl- channels causes passive water flow and consequent changes in cell volume, these channels may be considered to play a key role in EMT, which is characterized by significant morphological changes. In the present article, we highlight how EMT, which causes fibrosis and carcinogenesis in various tissues, is strongly associated with activation or inactivation of Cl- channels and discuss whether Cl- channels can lead to elucidation of the molecular mechanism of EMT in fibrosis of asthmatic airway remodeling.

PI3K/AKT signaling pathway as a critical regulator of epithelial-mesenchymal transition in colorectal tumor cells

Colorectal cancer (CRC) is one of the most frequent gastrointestinal malignancies that are considered as a global health challenge. Despite many progresses in therapeutic methods, there is still a high rate of mortality rate among CRC patients that is associated with poor prognosis and distant metastasis. Therefore, investigating the molecular mechanisms involved in CRC metastasis can improve the prognosis. Epithelial-mesenchymal transition (EMT) process is considered as one of the main molecular mechanisms involved in CRC metastasis, which can be regulated by various signaling pathways. PI3K/AKT signaling pathway has a key role in CRC cell proliferation and migration. In the present review, we discussed the role of PI3K/AKT pathway CRC metastasis through the regulation of the EMT process. It has been shown that PI3K/AKT pathway can induce the EMT process by down regulation of epithelial markers, while up regulation of mesenchymal markers and EMT-specific transcription factors that promote CRC metastasis. This review can be an effective step toward introducing the PI3K/AKT/EMT axis to predict prognosis as well as a therapeutic target among CRC patients. Video Abstract.

Biological impact and therapeutic perspective of targeting PI3K/Akt signaling in hepatocellular carcinoma: Promises and Challenges

Cancer progression results from activation of various signaling networks. Among these, PI3K/Akt signaling contributes to proliferation, invasion, and inhibition of apoptosis. Hepatocellular carcinoma (HCC) is a primary liver cancer with high incidence rate, especially in regions with high prevalence of viral hepatitis infection. Autoimmune disorders, diabetes mellitus, obesity, alcohol consumption, and inflammation can also lead to initiation and development of HCC. The treatment of HCC depends on the identification of oncogenic factors that lead tumor cells to develop resistance to therapy. The present review article focuses on the role of PI3K/Akt signaling in HCC progression. Activation of PI3K/Akt signaling promotes glucose uptake, favors glycolysis and increases tumor cell proliferation. It inhibits both apoptosis and autophagy while promoting HCC cell survival. PI3K/Akt stimulates epithelial-to-mesenchymal transition (EMT) and increases matrix-metalloproteinase (MMP) expression during HCC metastasis. In addition to increasing colony formation capacity and facilitating the spread of tumor cells, PI3K/Akt signaling stimulates angiogenesis. Therefore, silencing PI3K/Akt signaling prevents aggressive HCC cell behavior. Activation of PI3K/Akt signaling can confer drug resistance, particularly to sorafenib, and decreases the radio-sensitivity of HCC cells. Anti-cancer agents, like phytochemicals and small molecules can suppress PI3K/Akt signaling by limiting HCC progression. Being upregulated in tumor tissues and clinical samples, PI3K/Akt can also be used as a biomarker to predict patients' response to therapy.

A novel enterocyte-related 4-gene signature for predicting prognosis in colon adenocarcinoma

Background

Colon adenocarcinoma (COAD) is a fatal disease, and its cases are constantly increasing worldwide. Further, the therapeutic and management strategies for patients with COAD are still unsatisfactory due to the lack of accurate patient classification and prognostic models. Therefore, our study aims to identify prognostic markers in patients with COAD and construct a cell subtype-specific prognostic model with high accuracy and robustness.

Methods

Single-cell transcriptomic data of six samples were retrieved from the Gene expression omnibus (GEO) database. The cluster annotation and cell-cell communication analysis identified enterocytes as a key player mediating signal communication networks. A four-gene signature prognostic model was constructed based on the enterocyte-related differentially expressed genes (ERDEGs) in patients with COAD of the Cancer Genome Atlas cohort. The prognostic model was validated on three external validation cohorts from the GEO database. The correlation between immune cell infiltration, immunotherapy response, drug sensitivity, and the four-gene signature prognostic model was investigated. Finally, immunohistochemistry (IHC) was performed to determine the expression of the four genes.

Results

We found that the proportion of epithelial cells was obviously large in COAD samples. Further analysis of epithelial cells showed that the activity of the enterocytes was highest in the cell-cell communication network. Based on enterocyte data, 30 ERDEGs were identified and a 4-gene prognostic model including CPM, CLCA4, ELOVL6, and ATP2A3 was developed and validated. The risk score derived from this model was considered as an independent variable factor to predict overall survival. The patients were divided into high- and low-risk groups based on the median riskscore value. The correlation between immune cell infiltration, immunotherapy response, immune status, clinical characteristics, drug sensitivity, and risk score was analyzed. IHC confirmed the expression of signature genes in tissues from normal individuals, patients with polyps, and COAD.

Conclusion

In this study, we constructed and validated a novel four-gene signature prognostic model, which could effectively predict the response to immunotherapy and overall survival in patients with COAD. More importantly, this model provides useful insight into the management of colon cancer patients and aids in designing personalized therapy.

The effect of low molecular weight-polycyclic aromatic hydrocarbons responsive hsa_circ_0039929/hsa-miR-15b-3p_R-1/FGF2 circuit on inflammatory response of A549 cells via the PI3K/AKT pathway and epithelial-mesenchymal transition process

Inflammation is widely recognized as an essential inducer of epithelial-mesenchymal transition (EMT). Meanwhile, competitive endogenous RNA (ceRNA) has been involved in a variety of disease processes. Therefore, the aim of the current study is to explore the regulation of ceRNA in the PI3K/AKT pathway and EMT mechanism in inflammatory response caused by low molecular weight-polycyclic aromatic hydrocarbons (LMW-PAHs). The A549 cells were treated with an equal mixture of phenanthrene (Phe) and fluorene (Flu), and total RNA was extracted for transcriptome sequencing. The target regulation of ceRNA hsa_circ_0039929/hsa-miR-15b-3p_R-1/FGF2 was further determined for mechanism study. The mixture of Phe and Flu significantly upregulated the expressions of hsa_circ_0039929 and FGF2, down-regulated hsa-miR-15b-3p_R-1, activated the PI3K/AKT pathway and promoted EMT. Mechanically, the overexpression of hsa-miR-15b-3p_R-1 inhibited the expressions of hsa_circ_0039929 and FGF2, reversed the activation of PI3K/AKT signaling pathway by LMW-PAHs, and blocked the occurrence of EMT progression. Furthermore, knockdown of hsa_circ_0039929 could promote the levels of hsa-miR-15b-3p_R-1, while inhibit the expression of FGF2. The effects of hsa_circ_0039929 knockdowns on PI3K/AKT pathways and EMT progress resembled the hsa-miR-15b-3p_R-1 overexpression. All above suggested that ceRNA hsa_circ_0039929/hsa-miR-15b-3p_R-1/FGF2 played an important role in the inflammation and EMT caused by LMW-PAHs.

The TTYH3/MK5 Positive Feedback Loop regulates Tumor Progression via GSK3-β/β-catenin signaling in HCC

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-related death worldwide, and identification of novel targets is necessary for its diagnosis and treatment. This study aimed to investigate the biological function and clinical significance of tweety homolog 3 (TTYH3) in HCC. TTYH3 overexpression promoted cell proliferation, migration, and invasion and inhibited HCCM3 and Hep3B cell apoptosis. TTYH3 promoted tumor formation and metastasis in vivo. TTYH3 upregulated calcium influx and intracellular chloride concentration, thereby promoting cellular migration and regulating epithelial-mesenchymal transition-related protein expression. The interaction between TTYH3 and MK5 was identified through co-immunoprecipitation assays and protein docking. TTYH3 promoted the expression of MK5, which then activated the GSK3β/β-catenin signaling pathway. MK5 knockdown attenuated the activation of GSK3β/β-catenin signaling by TTYH3. TTYH3 expression was regulated in a positive feedback manner. In clinical HCC samples, TTYH3 was upregulated in the HCC tissues compared to nontumor tissues. Furthermore, high TTYH3 expression was significantly correlated with poor patient survival. The CpG islands were hypomethylated in the promoter region of TTYH3 in HCC tissues. In conclusion, we identified TTYH3 regulates tumor development and progression via MK5/GSK3-β/β-catenin signaling in HCC and promotes itself expression in a positive feedback loop.

Identification of Hub Genes in Colorectal Adenocarcinoma by Integrated Bioinformatics

An improved understanding of the molecular mechanism of colorectal adenocarcinoma is necessary to predict the prognosis and develop new target gene therapy strategies. This study aims to identify hub genes associated with colorectal adenocarcinoma and further analyze their prognostic significance. In this study, The Cancer Genome Atlas (TCGA) COAD-READ database and the gene expression profiles of GSE25070 from the Gene Expression Omnibus were collected to explore the differentially expressed genes between colorectal adenocarcinoma and normal tissues. The weighted gene co-expression network analysis (WGCNA) and differential expression analysis identified 82 differentially co-expressed genes in the collected datasets. Enrichment analysis was applied to explore the regulated signaling pathway in colorectal adenocarcinoma. In addition, 10 hub genes were identified in the protein–protein interaction (PPI) network by using the cytoHubba plug-in of Cytoscape, where five genes were further proven to be significantly related to the survival rate. Compared with normal tissues, the expressions of the five genes were both downregulated in the GSE110224 dataset. Subsequently, the expression of the five hub genes was confirmed by the Human Protein Atlas database. Finally, we used Cox regression analysis to identify genes associated with prognosis, and a 3-gene signature (CLCA1–CLCA4–GUCA2A) was constructed to predict the prognosis of patients with colorectal cancer. In conclusion, our study revealed that the five hub genes and CLCA1–CLCA4–GUCA2A signature are highly correlated with the development of colorectal adenocarcinoma and can serve as promising prognosis factors to predict the overall survival rate of patients.

<em>miR-19a</em> targeting <em>CLCA4</em> to regulate the proliferation, migration, and invasion of colorectal cancer cells

The role of miR-19a in colorectal cancer (CRC), a devastating disease with high mortality and morbidity, remains controversial. In the present study, we show that the level of miR-19a is significantly higher in clinical CRC tissue samples than in paracancerous tissue samples, and significantly higher in CRC cells lines HT29, SW480, and CaCO2 than in the normal human colon mucosal epithelial cell line NCM460. miR-19a mimics and inhibitors were synthesized and validated. Overexpression of miR-19a mimics significantly promoted, while miR-19a inhibitors inhibited, the proliferation, survival, migration, and invasion of SW480 and CaCO2 CRC cells. Furthermore, mRNA and protein levels of chloride channel accessory 4 (CLCA4) were lower in CRC cells and tissues. Bioinformatics and a luciferase reporter assay confirmed that CLCA4 was a miR-19a target. Further, miR-19a inhibition increased CLCA4 expression. The inhibitory effect of miR-19a on cell growth, survival, migration, and invasion was reversed by knockdown of CLCA4 expression. The data demonstrated that the miR-19a/CLCA4 axis modulates phospho-activation of the PI3K/AKT pathway in CRC cells. In conclusion, our results revealed that miR-19a overexpression decreases CLCA4 levels to promote CRC oncogenesis, suggesting that miR-19a inhibitors have potential applications for future therapeutic of CRC.

Proteomic analysis distinguishes extracellular vesicles produced by cancerous versus healthy pancreatic organoids

Extracellular vesicles (EVs) are produced and released by both healthy and malignant cells and bear markers indicative of ongoing biological processes. In the present study we utilized high resolution flow cytometry to detect EVs in the plasma of patients with pancreatic ductal adenocarcinoma (PDAC) and in the supernatants of PDAC and healthy control (HC) pancreatic organoid cultures. Using ultrafiltration and size exclusion chromatography, PDAC and HC pancreatic organoid EVs were isolated for mass spectrometry analysis. Proteomic and functional protein network analysis showed a striking distinction in that EV proteins profiled in pancreatic cancer organoids were involved in vesicular transport and tumorigenesis while EV proteins in healthy organoids were involved in cellular homeostasis. Thus, the most abundant proteins identified in either case represented non-overlapping cellular programs. Tumor-promoting candidates LAMA5, SDCBP and TENA were consistently upregulated in PDAC EVs. Validation of specific markers for PDAC EVs versus healthy pancreatic EVs will provide the biomarkers and enhanced sensitivity necessary to monitor early disease or disease progression, with or without treatment. Moreover, disease-associated changes in EV protein profiles provide an opportunity to investigate alterations in cellular programming with disease progression.

Identification of Down-Regulated ADH1C is Associated With Poor Prognosis in Colorectal Cancer Using Bioinformatics Analysis

Colorectal cancer (CRC) is the second most deadly cancer in the whole world, with the underlying mechanisms largely indistinct. Therefore, we aimed to identify significant pathways and genes involved in the initiation, formation and poor prognosis of CRC using bioinformatics methods. In this study, we compared gene expression profiles of CRC cases with those from normal colorectal tissues from three chip datasets (GSE33113, GSE23878 and GSE41328) to identify 105 differentially expressed genes (DEGs) that were common to the three datasets. Gene ontology and Kyoto Encyclopedia of Genes and Genomes pathway analyses showed that the highest proportion of up-regulated DEGs was involved in extracellular region and cytokine-cytokine receptor interaction pathways. Integral components of membrane and bile secretion pathways were identified as containing down-regulated DEGs. 13 hub DEGs were chosen and their expression were further validated by GEPIA. Only four DEGs (ADH1C, CLCA4, CXCL8 and GUCA2A) were associated with a significantly lower overall survival after the prognosis analysis. Lower ADH1C protein level and higher CXCL8 protein level were verified by immunohistochemical staining and western blot in clinical CRC and normal colorectal tissues. In conclusion, our study indicated that the extracellular tumor microenvironment and bile metabolism pathways play critical roles in the formation and progression of CRC. Furthermore, we confirmed ADH1C being down-regulated in CRC and reported ADH1C as a prognostic predictor for the first time.

Analyzing large scale gene expression data in colorectal cancer reveals important clues; CLCA1 and SELENBP1 downregulated in CRC not in normal and not in adenoma

Early detection of colorectal cancer (CRC) increases the chances of survival and reduces the therapeutic problems and costs of treatment. Since molecular biomarkers can help us diagnose colorectal cancer early, we need to identify novel gene for predicting the early stages of tumorigenesis. Here, we integrated five independent CRC gene expression datasets derived from expression profiling by array comparing CRC with normal samples in: GSE21510, GSE4107, GSE25071, GSE15781 dataset, and GSE8671 dataset, including 64 samples from 32 patients comparing 32 colonic normal mucosa with 32 colorectal adenoma. To detect genes that expressed differentially in experimental circumstances of these datasets, we used web tool of GEO2R to compare groups of samples in the GEO data series. Furthermore, we constructed the protein-protein interactions network by STRING database for mostly downregulated genes and the expression of their members in PPI network were studied into five datasets separately. Also, the level of expression of selected biomarker genes in different stages of CRC compared to normal was studied. Our data revealed 17 common downregulated genes (average fold change (FC) in five tests ≥6) in CRC in comparison with normal (Test 1 to Test 4) and in adenoma compared with normal (Test 5). Studying of gene expression of PPI network members of these downregulated genes led to identifying of CLCA1, SELENBP1, CWC25, ACOT11, GUCY2C and ALDH1A1 as suppressor genes and PTGS2, PROCR, MOCS3 and NFS1 as oncogenes which respectively downregulated and upregulated in CRC. Since decreasing of gene expression was seen in CRC comparing with normal and due to no different expression seen for these 10 genes in adenoma, they, especially CLCA1 and SELENBP1, could be considered as biomarkers for early detection of CRC. Before using these signature genes in the clinic; however, further validations are required.

Expression of the CLCA4 Gene in Esophageal Carcinoma and Its Impact on the Biologic Function of Esophageal Carcinoma Cells

Background

Esophageal carcinoma (ESCA) is one of the malignant tumors with a high mortality rate worldwide, which seriously affects people's health. Calcium-activated chloride channel 4 (CLCA4) was reported to be a tumor inhibitor in hepatocellular carcinoma. Nevertheless, the role of CLCA4 in ESCA is still unclear.

Methods

RT-qPCR and western blot assay were used to test the expression pattern of CLCA4 in ESCA tissues and cells. CCK-8 assay was performed to detect the effect of CLCA4 overexpression on cell proliferation in ESCA cells. Transwell assay was used to measure the effect of CLCA4 upregulation on migration and invasion abilities of ESCA cells. Animal experiments were conducted to investigate the role of CLCA4 upregulation in tumor growth in vivo.

Results

CLCA4 was significantly reduced in ESCA tissues and correlated with T stage, differentiation, and lymph node metastasis. CLCA4 overexpression was found to inhibit cell proliferation, migration, invasion, and EMT progression in ESCA cells. Moreover, CLCA4 overexpression suppressed tumor growth in vivo.

Conclusion

CLCA4 was suggested to act as a tumor inhibitor in ESCA and might be a therapeutic target gene for the treatment of patients with ESCA.

CLCA4 and MS4A12 as the significant gene biomarkers of primary colorectal cancer

Background: Primary colorectal cancer (PCRC) is a common digestive tract cancer in the elderly. However, the treatment effect of PCRC is still limited, and the long-term survival rate is low. Therefore, further exploring the pathogenesis of PCRC, and searching for specific molecular targets for diagnosis are the development trends of precise medical treatment, which have important clinical significance.

Methods: The public data were downloaded from Gene Expression Omnibus (GEO) database. Verification for repeatability of intra-group data was performed by Pearson’s correlation test and principal component analysis. Differentially expressed genes (DEGs) between normal and PCRC were identified, and the protein–protein interaction (PPI) network was constructed. Significant module and hub genes were found in the PPI network. A total of 192 PCRC patients were recruited between 2010 and 2019 from the Fourth Hospital of Hebei Medical University. RT-PCR was used to measure the relative expression of CLCA4 and MS4A12. Furthermore, the study explored the effect of expression of CLCA4 and MS4A12 for overall survival.

Results: A total of 53 DEGs were identified between PCRC and normal colorectal tissues. Ten hub genes concerned to PCRC were screened, namely CLCA4, GUCA2A, GCG, SST, MS4A12, PLP1, CHGA, PYY, VIP, and GUCA2B. The PCRC patients with low expression of CLCA4 and MS4A12 has a worse overall survival than high expression of CLCA4 and MS4A12 (P<0.05).

Conclusion: The research of DEGs in PCRC (53 DEGs, 10 hub genes, especially CLCA4 and MS4A12) and related signaling pathways is conducive to the differential analysis of the molecular mechanism of PCRC.

Identification of Hub Genes Associated With Hepatocellular Carcinoma Using Robust Rank Aggregation Combined With Weighted Gene Co-expression Network Analysis

Background

Bioinformatics provides a valuable tool to explore the molecular mechanisms underlying pathogenesis of hepatocellular carcinoma (HCC). To improve prognosis of patients, identification of robust biomarkers associated with the pathogenic pathways of HCC remains an urgent research priority.

Methods

We employed the Robust Rank Aggregation method to integrate nine qualified HCC datasets from the Gene Expression Omnibus. A robust set of differentially expressed genes (DEGs) between tumor and normal tissue samples were screened. Weighted gene co-expression network analysis was applied to cluster DEGs and the key modules related to clinical traits identified. Based on network topology analysis, novel risk genes derived from key modules were mined and biological verification performed. The potential functions of these risk genes were further explored with the aid of miRNA–mRNA regulatory networks. Finally, the prognostic ability of these genes was assessed by constructing a clinical prediction model.

Results

Two key modules showed significant association with clinical traits. In combination with protein–protein interaction analysis, 29 hub genes were identified. Among these genes, 19 from one module showed a pattern of upregulation in HCC and were associated with the tumor node metastasis stage, and 10 from the other module displayed the opposite trend. Survival analyses indicated that all these genes were significantly related to patient prognosis. Based on the miRNA-mRNA regulatory network, 29 genes strongly linked to tumor activity were identified. Notably, five of the novel risk genes, ABAT, DAO, PCK2, SLC27A2, and HAO1, have rarely been reported in previous studies. Gene set enrichment analysis for each gene revealed regulatory roles in proliferation and prognosis of HCC. Least absolute shrinkage and selection operator regression analysis further validated DAO, PCK2, and HAO1 as prognostic factors in an external HCC dataset.

Conclusion

Analysis of multiple datasets combined with global network information presents a successful approach to uncover the complex biological mechanisms of HCC. More importantly, this novel integrated strategy facilitates identification of risk hub genes as candidate biomarkers for HCC, which could effectively guide clinical treatments.

miR-15b, a diagnostic biomarker and therapeutic target, inhibits oesophageal cancer progression by regulating the PI3K/AKT signalling pathway

MicroRNA (miR)-15b is an important regulator in several types of cancer, such as gastric cancer, colorectal cancer and oesophageal squamous cell carcinoma. The PI3K/AKT signalling pathway has been implicated in the growth and metastasis of oesophageal cancer (EC). The aim of the present study was to investigate the biological effects of miR-15b in EC, as well as the underlying mechanism involving the PI3K/AKT signalling pathway. The present study included 74 patients with EC and 74 healthy volunteers. The expression of miR-15b in peripheral blood mononuclear cells (PBMCs) and EC cell lines was evaluated via reverse transcription-quantitative PCR. The receiver operating characteristic curve was plotted to determine the diagnostic significance of miR-15b. EC cell viability, apoptosis, migration and invasion were analysed by conducting MTT, flow cytometry and transwell assays, respectively. Protein expression levels were analysed via western blotting. The results indicated that PBMCs isolated from patients with EC had lower miR-15b expression levels compared with PBMCs isolated from healthy volunteers. In patients with EC, miR-15b expression was strongly associated with tumour size, lymph node metastasis, TNM stage, fibrous membrane invasion and histologic grade. The results of the gain/loss-of-function in vitro experiments indicated that miR-15b inhibited EC cell viability, migration and invasion, facilitated EC cell apoptosis and attenuated the PI3K/AKT signalling pathway in EC109 and TE10 cells. Treatment of EC cells with the PI3K/AKT pathway agonist recilisib displayed the opposite effects, blocking the inhibitory function of miR-15b mimic on EC cell viability, migration and invasion. In summary, the results indicated that miR-15b suppressed EC cell viability, migration and invasion, and promoted EC cell apoptosis by inhibiting the PI3K/AKT signalling pathway.

How Dysregulated Ion Channels and Transporters Take a Hand in Esophageal, Liver, and Colorectal Cancer

Over the last two decades, the understanding of how dysregulated ion channels and transporters are involved in carcinogenesis and tumor growth and progression, including invasiveness and metastasis, has been increasing exponentially. The present review specifies virtually all ion channels and transporters whose faulty expression or regulation contributes to esophageal, hepatocellular, and colorectal cancer. The variety reaches from Ca²⁺, K⁺, Na⁺, and Cl^- channels over divalent metal transporters, Na⁺ or Cl^- coupled Ca²⁺, HCO₃^- and H⁺ exchangers to monocarboxylate carriers and organic anion and cation transporters. In several cases, the underlying mechanisms by which these ion channels/transporters are interwoven with malignancies have been fully or at least partially unveiled. Ca²⁺, Akt/NF-κB, and Ca²⁺- or pH-dependent Wnt/β-catenin signaling emerge as cross points through which ion channels/transporters interfere with gene expression, modulate cell proliferation, trigger epithelial-to-mesenchymal transition, and promote cell motility and metastasis. Also miRs, lncRNAs, and DNA methylation represent potential links between the misexpression of genes encoding for ion channels/transporters, their malfunctioning, and cancer. The knowledge of all these molecular interactions has provided the basis for therapeutic strategies and approaches, some of which will be broached in this review.

Downregulation of CLCA4 expression is associated with the development and progression of colorectal cancer

The molecular mechanisms involved in the development and progression of colorectal cancer (CRC) are not completely understood. The present study aimed to identify potential novel genes involved in the development and progression of CRC. Database analysis revealed that the mRNA level of the chloride channel accessory 4 (CLCA4) was frequently lower in primary tumor tissues compared with that in corresponding non-cancerous colon tissues, and was even lower in liver metastases than in primary tumors. Further analyses through The Human Protein Atlas (THPA) website and immunohistochemistry (IHC)-based tissue microarray (TMA) confirmed that CLCA4 mRNA and protein expression were downregulated in CRC tissues. Furthermore, IHC-based TMA analysis revealed a gradual decrease in CLCA4 protein expression among colorectal normal, adenoma and carcinoma tissues. Survival analysis revealed that the decrease in CLCA4 mRNA expression was associated with the overall survival rate of patients with different types of tumor, including CRC, breast cancer, head and neck cancer and stomach cancer. Overall, downregulated CLCA4 expression may influence the development and progression of CRC.

Identification of Genes Related to Clinicopathological Characteristics and Prognosis of Patients with Colorectal Cancer

The aim of this study was to identify genes with clinical significance in colorectal cancer (CRC). Gene expression profiles of 585 CRC tissues and 61 normal colorectal tissues from Gene Expression Omnibus (GEO) and The Cancer Genome Atlas (TCGA) databases were used to identify differentially expressed genes (DEGs) between CRC and normal colorectal tissues. DAVID and KOBAS tools were used to explore Gene Ontology (GO) and KEGG pathways enriched by DEGs, respectively. In addition, TCGA data sets were also used to identify prognostic factors and develop a prognostic prediction model for CRC. A total of 353 DEGs including 117 upregulated and 236 downregulated genes in CRC were identified based on GSE32323 data set. These DEGs were significantly enriched in the biological process related to the regulation of cell proliferation and 50 signaling pathways, such as "TGF-beta signaling pathway," "Wnt signaling pathway," and "Jak-STAT signaling pathway." GCG, ADH1B, SLC4A4, ZG16, and CLCA4 were the top five downregulated in CRC. FOXQ1, LGR5, CLDN1, KRT23, and DPEP1 were the top five upregulated in CRC. KRT23 expression could affect tumor stage and regional lymph node metastasis in CRC patients. FOXQ1 expression could affect tumor distant metastasis in CRC patients. Survival analysis indicated that SLC4A4 expression was associated with the prognosis of CRC patients. Prognostic prediction model developed based on age, tumor stage, and SLC4A4 expression exhibited an efficient performance in predicting 1-, 3-, and 5-year overall survival of CRC patients. In conclusion, the current study identified several genes and pathways related to CRC, which provided new insight in understanding molecular mechanism of tumorigenesis and development of CRC.

MAP2K4 interacts with Vimentin to activate the PI3K/AKT pathway and promotes breast cancer pathogenesis

Mitogen-activated protein kinase kinase 4 (MAP2K4) is a member of the mitogen-activated protein kinase (MAPK) activator family. MAPK signaling plays a significant role in cell proliferation, differentiation, transcriptional regulation, and development. However, specific function and mechanism of MAP2K4 in breast cancer have not been clarified. According to our study, overexpressed MAP2K4 in breast cancer cells increased proliferation, migration, and invasion in vivo and in vitro, while MAP2K4 knockdown restored the effects. Subsequent mechanistic analyses demonstrated that MAP2K4 promoted cell proliferation, migration, and invasion by activating phosphoinositide-3-kinase (PI3K)/AKT signaling, the downstream proteins, c-JUN, the G1/S cell cycle, and the epithelial-to-mesenchymal transition (EMT). Meanwhile, MAP2K4 interacted with Vimentin and further propagated the malignant phenotype. Furthermore, patients with high MAP2K4 and Vimentin expression levels had poorer overall survival rates than those with low expression levels of both proteins. Our studies demonstrated that MAP2K4 has the potential to serve as an oncogene in breast cancer and it activates the phosphorylated PI3K/AKT signaling pathway to activate downstream cycle-associated proteins and EMT signals while interacting with Vimentin to promote breast cancer cells proliferation, migration, and invasion. In our study, MAP2K4 and Vimentin co-expression is confirmed to be an unfavorable factor in breast cancer.

TIP-B1 promotes kidney clear cell carcinoma growth and metastasis via EGFR/AKT signaling

Kidney clear cell carcinoma (KIRC) is the most prevalent kidney malignancy. Accumulating evidence shows that high expression of TIP-B1 correlates with development of tumor progression. However, the detailed functions of TIP-B1 in the KIRC remain to be further elucidated. Here, we firstly found TIP-B1 expression was significantly increased in KIRC compared with adjacent normal tissues. What’s more, higher expression of TIP-B1 were correlated with aggressive clinico-pathological characteristics. In vitro assay found TIP-B1 knockdown dramatically inhibited KIRC cells proliferation, migration and invasion. In vivo assay found down regulated TIP-B1 could suppress tumor growth and metastasis. Mechanism analysis indicated that TIP-B1 could bind EGFR and suppress EGFR degradation, then promoted EGF-induced AKT signaling. Together, TIP-B1 could be applied as an independent risk factor to predict KIRC progression and metastasis. Targeting TIP-B1 might be a new potential therapeutic strategy for KIRC treatment.

Calcium-Activated Chloride Channel A4 (CLCA4) Plays Inhibitory Roles in Invasion and Migration Through Suppressing Epithelial-Mesenchymal Transition via PI3K/AKT Signaling in Colorectal Cancer

Background

Calcium-activated chloride channel A4 (CLCA4) is known as a tumor suppressor which contributes to the progression of a number of types of malignant tumors. However, little is known about the functional roles of CLCA4 in colorectal cancer (CRC).

Material/Methods

In this study, the expression patterns and dysregulation of mRNAs in CRC tissues were profiled by analyzing GSE21510 datasets from Gene Expression Omnibus database which contains 104 primary hepatocellular carcinoma tissues and 24 normal liver tissues, and by performing Kaplan-Meier analysis of TCGA data. Additionally, immunohistochemistry and quantitative real-time polymerase chain reaction (qRT-PCR) were performed using clinical tissues collected at our institute. In order to explore the functional role of CLCA4, gain-of-function cell models were constructed in SW620 and LoVo cells. Wound healing assay and Transwell assay were carried out to access the cell migration and invasion ability.

Results

It was found that CLCA4 was an independent predictor for overall survival and lymph node metastasis. Additionally, immunohistochemistry and qRT-PCR results of the clinical tissues collected as part of our study further confirmed this correlation. In vitro experiments demonstrated that over-expression of CLCA4 could inhibit cell migration and invasion by suppressing epithelial-mesenchymal transition (EMT) via PI3K/ATK signaling and change the expression patterns of EMT markers in CLCA4-gain-of-function cell models.

Conclusions

CLCA4 inhibits migration and invasion by suppressing EMT via PI3K/ATK signaling and predicts favorable prognosis of CRC which may help to distinguish potential risk of lymph node metastasis in CRC.

Emerging roles for multifunctional ion channel auxiliary subunits in cancer

Several superfamilies of plasma membrane channels which regulate transmembrane ion flux have also been shown to regulate a multitude of cellular processes, including proliferation and migration. Ion channels are typically multimeric complexes consisting of conducting subunits and auxiliary, non-conducting subunits. Auxiliary subunits modulate the function of conducting subunits and have putative non-conducting roles, further expanding the repertoire of cellular processes governed by ion channel complexes to processes such as transcellular adhesion and gene transcription. Given this expansive influence of ion channels on cellular behaviour it is perhaps no surprise that aberrant ion channel expression is a common occurrence in cancer. This review will focus on the conducting and non-conducting roles of the auxiliary subunits of various Ca2+, K+, Na+ and Cl- channels and the burgeoning evidence linking such auxiliary subunits to cancer. Several subunits are upregulated (e.g. Cavβ, Cavγ) and downregulated (e.g. Kvβ) in cancer, while other subunits have been functionally implicated as oncogenes (e.g. Navβ1, Cavα2δ1) and tumour suppressor genes (e.g. CLCA2, KCNE2, BKγ1) based on in vivo studies. The strengthening link between ion channel auxiliary subunits and cancer has exposed these subunits as potential biomarkers and therapeutic targets. However further mechanistic understanding is required into how these subunits contribute to tumour progression before their therapeutic potential can be fully realised.