A positive crosstalk between CXCR4 and CXCR2 promotes gastric cancer metastasis

The CXCR2 chemokine receptor: A new target for gastric cancer therapy

Gastric cancer (GC) is one of the most common malignant tumors in the world, and current treatments are still based on surgery and drug therapy. However, due to the complexity of immunosuppression and drug resistance, the treatment of gastric cancer still faces great challenges. Chemokine receptor 2 (CXCR2) is one of the most common therapeutic targets in targeted therapy. As a G protein-coupled receptor, CXCR2 and its ligands play important roles in tumorigenesis and progression. The abnormal expression of these genes in cancer plays a decisive role in the recruitment and activation of white blood cells, angiogenesis, and cancer cell proliferation, and CXCR2 is involved in various stages of tumor development. Therefore, interfering with the interaction between CXCR2 and its ligands is considered a possible target for the treatment of various tumors, including gastric cancer.

Crosstalk between CXCL12/CXCR4/ACKR3 and the STAT3 Pathway

The reciprocal modulation between the CXCL12/CXCR4/ACKR3 axis and the STAT3 signaling pathway plays a crucial role in the progression of various diseases and neoplasms. Activation of the CXCL12/CXCR4/ACKR3 axis triggers the STAT3 pathway through multiple mechanisms, while the STAT3 pathway also regulates the expression of CXCL12. This review offers a thorough and systematic analysis of the reciprocal regulatory mechanisms between the CXCL12/CXCR4/ACKR3 signaling axis and the STAT3 signaling pathway in the context of diseases, particularly tumors. It explores the potential clinical applications in tumor treatment, highlighting possible therapeutic targets and novel strategies for targeted tumor therapy.

Clinicopathological significance of microsatellite instability and immune escape mechanism in patients with gastric solid-type poorly differentiated adenocarcinoma

BACKGROUND

In gastric solid-type poorly differentiated adenocarcinoma (PDA), the role of microsatellite instability and immune escape mechanism remains unclear. The current study aimed to elucidate the clinical significance of mismatch repair (MMR) status, genome profile, C-X-C motif chemokine receptor 2 (CXCR2) expression, and myeloid-derived suppressor cell (MDSC) infiltration in solid-type PDA.

METHODS

In total, 102 primary solid-type PDA cases were retrieved, and classified into 46 deficient-MMR (dMMR) and 56 proficient-MMR (pMMR) cases based on immunohistochemistry (IHC) and polymerase chain reaction-based molecular testing results. The mRNA expression profiles (NanoString nCounter Assay) of stage-matched dMMR (n = 6) and pMMR (n = 6) cases were examined. The CXCR2 expression and MDSC infiltration (CD11b- and CD33-positive cells) were investigated via IHC in all solid-type PDA cases.

RESULTS

mRNA analysis revealed several differentially expressed genes and differences in biological behavior between the dMMR (n = 46) and pMMR (n = 56) groups. In the multivariate analysis, the dMMR status was significantly associated with a longer disease-free survival (hazard ratio = 5.152, p = 0.002) and overall survival (OS) (hazard ratio = 5.050, p = 0.005). CXCR2-high expression was significantly correlated with a shorter OS in the dMMR group (p = 0.018). A high infiltration of CD11b- and CD33-positive cells was significantly correlated with a shorter OS in the pMMR group (p = 0.022, 0.016, respectively).

CONCLUSIONS

dMMR status can be a useful prognostic predictor, and CXCR2 and MDSCs can be novel therapeutic targets in patients with solid-type PDA.

Progression of radio-labeled molecular imaging probes targeting chemokine receptors

Chemokine receptors are significantly expressed in the surface of most inflammatory cells and tumor cells. Guided by chemokines, inflammatory cells which express the relevant chemokine receptors migrate to inflammatory lesions and participate in the evolution of inflammation diseases. Similarly, driven by chemokines, immune cells infiltrate into tumor lesions not only induces alterations in the tumor microenvironment, disrupting the efficacy of tumor therapies, but also has the potential to selectively target tumoral cells and diminish tumor progression. Chemokine receptors, which are significantly expressed on the surface of tumor cell membranes, are regulated by chemokines and initiate tumor-associated signaling pathways within tumor cells, playing a complex role in tumor progression. Based on the antagonists targeting chemokine receptors, radionuclide-labeled molecular imaging probes have been developed for the emerging application of molecular imaging in diseases such as tumors and inflammation. The value and limitations of molecular probes in disease imaging are worth reviewing.

The Role of LMP1 in Epstein-Barr Virus-associated Gastric Cancer

EBV promotes many cancers such as lymphoma, nasopharyngeal carcinoma, and gastric; Latent Membrane Protein 1 (LMP1) is considered to be a major oncogenic protein encoded by Epstein- Barr virus (EBV). LMP1 functions as a carcinogen in lymphoma and nasopharyngeal carcinoma, and LMP1 may also promote gastric cancer. The expression level of LMP1 in host cells is a key determinant in tumorigenesis and maintenance of virus specificity. By promoting cell immortalization and cell transformation, promoting cell proliferation, affecting immunity, and regulating cell apoptosis, LMP1 plays a crucial tumorigenic role in epithelial cancers. However, very little is currently known about LMP1 in Epstein-Barr virus-associated gastric cancer (EBVaGC); the main reason is that the expression level of LMP1 in EBVaGC is comparatively lower than other EBV-encoded proteins, such as The Latent Membrane Protein 2A (LMP2A), Epstein-Barr nuclear antigen 1 (EBNA1) and BamHI-A rightward frame 1 (BARF1), to date, there are few studies related to LMP1 in EBVaGC. Recent studies have demonstrated that LMP1 promotes EBVaGC by affecting The phosphatidylinositol 3-kinase- Akt (PI3K-Akt), Nuclear factor-kappa B (NF-κB), and other signaling pathways to regulate many downstream targets such as Forkhead box class O (FOXO), C-X-C-motif chemokine receptor (CXCR), COX-2 (Cyclooxygenase-2); moreover, the gene methylation induced by LMP1 in EBVaGC has become one of the characteristics that distinguish this gastric cancer (GC) from other types of gastric cancer and LMP1 also promotes the formation of the tumor microenvironment (TME) of EBVaGC in several ways. This review synthesizes previous relevant literature, aiming to highlight the latest findings on the mechanism of action of LMP1 in EBVaGC, summarize the function of LMP1 in EBVaGC, lay the theoretical foundation for subsequent new research on LMP1 in EBVaGC, and contribute to the development of novel LMP1-targeted drugs.

Identification and validation of a T cell marker gene-based signature to predict prognosis and immunotherapy response in gastric cancer

Although the role of T cells in tumor immunity and modulation of the tumor microenvironment (TME) has been extensively studied, their precise involvement in gastric adenocarcinoma remains inadequately explored. In this work, we analyzed the single-cell RNA sequencing data set in GSE183904 and identified 322 T cell marker genes using the "FindAllMarkers" method of the R package "Seurat". STAD patients in the TCGA database were divided into high-risk and low-risk categories based on risk scores. The five-gene prediction signature based on T cell marker genes can predict the prognosis of gastric cancer patients with high accuracy. In the training cohort, the areas under the receiver operating characteristic (ROC) curve were 0.667, 0.73, and 0.818 at 1, 3, and 5 years. External validation of the predictive signature was also performed using multiple clinical subgroups and GEO cohorts. To help with practical application, a diagnostic model was created that shows values of 0.732, 0.752, and 0.816 for the relevant areas under the ROC curve at 1, 3, and 5 years. The T cell marker genes identified in this study may serve as potential therapeutic targets, and the developed predictive signatures and nomograms may aid in the clinical management of gastric cancer.

Transcriptomic analysis reveals the promotion of lymph node metastasis by Helicobacter pylori infection via upregulating chemokine (C-X-C motif) receptor 2 expression in gastric carcinoma

Gastric carcinoma (GC) progression is mainly caused by local aggression and lymph node metastasis. However, some patients with early T-stage disease have lymph node metastasis, whereas some patients with late T-stage disease do not have lymph node metastasis, which indicates that invasion and metastasis are not always sequential in some GC patients. In the present study, the data of 101 GC cases were acquired from TCGA and divided into T-late-N-negative and T-early-N-positive groups according to pathological stages. A total of 338 genes were identified as differential genes between the T-late-N-negative and T-early-N-positive groups. GSEA showed that epithelial cell signaling in the Helicobacter pylori (HP) infection pathway was enriched in the T-early-N-positive group. MB staining indicated that the HP infection rate was 63% (39/62) in N-positive patients compared to 42% (16/38) in N-negative patients. To investigate the potential mechanism, we focused on the gene chemokine (C-X-C motif) receptor 2 (CXCR2), which was not only clustered in the gene set of epithelial cells signaling in the HP infection pathway but also significantly upregulated in T-early-N-positive GC by the analysis of the different genes based on the TCGA dataset. A meta-analysis showed that CXCR2 expression was positively correlated with N-stage but not with T-stage in GC. This study indicated that invasion and metastasis could be independent processes driven by different molecular mechanisms in some GC patients. HP infection was a potential factor that promoted lymph node metastasis by upregulating CXCR2 expression.

The regulatory role of cancer stem cell marker gene CXCR4 in the growth and metastasis of gastric cancer

Single-cell RNA sequencing (scRNA-seq) and bulk RNA sequencing (bulk RNA-seq) are increasingly used for screening genes involved in carcinogenesis due to their capacity for dissecting cellular heterogeneity. This study aims to reveal the molecular mechanism of the cancer stem cells (CSCs) marker gene CXCR4 in gastric cancer (GC) growth and metastasis through scRNA-seq combined with bulk RNA-seq. GC-related scRNA-seq data were downloaded from the GEO database, followed by UMAP cluster analysis. Non-malignant cells were excluded by the K-means algorithm. Bulk RNA-seq data and clinical sample information were downloaded from the UCSC Xena database. GO and KEGG pathway analyses validated the correlation between genes and pathways. In vitro and in vivo functional assays were used to examine the effect of perturbed CXCR4 on malignant phenotypes, tumorigenesis, and liver metastasis. A large number of highly variable genes were identified in GC tissue samples. The top 20 principal components were selected, and the cells were clustered into 6 cell types. The C4 cell cluster from malignant epithelial cells might be CSCs. CXCR4 was singled out as a marker gene of CSCs. GC patients with high CXCR4 expression had poor survival. Knockdown of CXCR4 inhibited the malignant phenotypes of CSCs in vitro and curtailed tumorigenesis and liver metastasis in nude mice. CSC marker gene CXCR4 may be a key gene facilitating malignant phenotypes of CSCs, which thus promotes tumor growth and liver metastasis of GC.

Therapeutic inhibition of CXCR1/2: where do we stand?

Mounting experimental evidence from in vitro and in vivo animal studies points to an essential role of the CXCL8-CXCR1/2 axis in neutrophils in the pathophysiology of inflammatory and autoimmune diseases. In addition, the pathogenetic involvement of neutrophils and the CXCL8-CXCR1/2 axis in cancer progression and metastasis is increasingly recognized. Consequently, therapeutic targeting of CXCR1/2 or CXCL8 has been intensively investigated in recent years using a wide array of in vitro and animal disease models. While a significant benefit for patients with unwanted neutrophil-mediated inflammatory conditions may be expected from a potential clinical use of inhibitors, their use in severe infections or sepsis might be problematic and should be carefully and thoroughly evaluated in animal models and clinical trials. Translating the approaches using inhibitors of the CXCL8-CXCR1/2 axis to cancer therapy is definitively a new and promising research avenue, which parallels the ongoing efforts to clearly define the involvement of neutrophils and the CXCL8-CXCR1/2 axis in neoplastic diseases. Our narrative review summarizes the current literature on the activation and inhibition of these receptors in neutrophils, key inhibitor classes for CXCR2 and the therapeutic relevance of CXCR2 inhibition focusing here on gastrointestinal diseases.

The Clinical Significance and Role of CXCL1 Chemokine in Gastrointestinal Cancers

One area of cancer research is the interaction between cancer cells and immune cells, in which chemokines play a vital role. Despite this, a comprehensive summary of the involvement of C-X-C motif ligand 1 (CXCL1) chemokine (also known as growth-regulated gene-α (GRO-α), melanoma growth-stimulatory activity (MGSA)) in cancer processes is lacking. To address this gap, this review provides a detailed analysis of CXCL1's role in gastrointestinal cancers, including head and neck cancer, esophageal cancer, gastric cancer, liver cancer (hepatocellular carcinoma (HCC)), cholangiocarcinoma, pancreatic cancer (pancreatic ductal adenocarcinoma), and colorectal cancer (colon cancer and rectal cancer). This paper presents the impact of CXCL1 on various molecular cancer processes, such as cancer cell proliferation, migration, and invasion, lymph node metastasis, angiogenesis, recruitment to the tumor microenvironment, and its effect on immune system cells, such as tumor-associated neutrophils (TAN), regulatory T (T_reg) cells, myeloid-derived suppressor cells (MDSCs), and macrophages. Furthermore, this review discusses the association of CXCL1 with clinical aspects of gastrointestinal cancers, including its correlation with tumor size, cancer grade, tumor-node-metastasis (TNM) stage, and patient prognosis. This paper concludes by exploring CXCL1's potential as a therapeutic target in anticancer therapy.

An Update of G-Protein-Coupled Receptor Signaling and Its Deregulation in Gastric Carcinogenesis

G-protein-coupled receptors (GPCRs) belong to a cell surface receptor superfamily responding to a wide range of external signals. The binding of extracellular ligands to GPCRs activates a heterotrimeric G protein and triggers the production of numerous secondary messengers, which transduce the extracellular signals into cellular responses. GPCR signaling is crucial and imperative for maintaining normal tissue homeostasis. High-throughput sequencing analyses revealed the occurrence of the genetic aberrations of GPCRs and G proteins in multiple malignancies. The altered GPCRs/G proteins serve as valuable biomarkers for early diagnosis, prognostic prediction, and pharmacological targets. Furthermore, the dysregulation of GPCR signaling contributes to tumor initiation and development. In this review, we have summarized the research progress of GPCRs and highlighted their mechanisms in gastric cancer (GC). The aberrant activation of GPCRs promotes GC cell proliferation and metastasis, remodels the tumor microenvironment, and boosts immune escape. Through deep investigation, novel therapeutic strategies for targeting GPCR activation have been developed, and the final aim is to eliminate GPCR-driven gastric carcinogenesis.

KDM6B promotes gastric carcinogenesis and metastasis via upregulation of CXCR4 expression

KDM6B (Lysine-specific demethylase 6B) is a histone lysine demethyltransferase that plays a key role in many types of cancers. However, its potential role in gastric cancer (GC) remains unclear. Here, we focused on the clinical significance and potential role of KDM6B in GC. We found that the KDM6B expression is upregulated in GC tissues and that its high expression in patients is related to poor prognosis. KDM6B ectopic expression promotes GC cells' proliferation and metastasis, while its inhibition has opposite effects in vitro and in vivo. Mechanistically, KDM6B promotes GC cells proliferation and metastasis through its enzymatic activity through the induction of H3K27me3 demethylation near the CXCR4 (C-X-C chemokine receptor type 4) promoter region, resulting in the upregulation of CXCR4 expression. Furthermore, H. pylori was found to induce KDM6B expression. In conclusion, our results suggest that KDM6B is aberrantly expressed in GC and plays a key role in gastric carcinogenesis and metastasis through CXCR4 upregulation. Our work also suggests that KDM6B may be a potential oncogenic factor and a therapeutic target for GC.

Chemokine/GPCR Signaling-Mediated EMT in Cancer Metastasis

Metastasis, the chief cause of cancer-related deaths, is associated with epithelial-mesenchymal transition (EMT). In the tumor microenvironment, EMT can be triggered by chemokine/G-protein-coupled receptor (GPCR) signaling, which is closely associated with tumor progression. However, the functional links between chemokine/GPCR signaling-mediated EMT and metastasis remain unclear. Herein, we summarized the mechanisms of chemokine/GPCR signaling-mediated EMT with an insight into facilitating metastasis and clarified the role of chemokine in the local invasion, intravasation, circulation, extravasation, and colonization, respectively. Moreover, several potential pathways that might contribute to EMT based on the latest studies on GPCR signaling were proposed, including signaling mediated by G protein, β-arrestin, intracellular, dimerization activation, and transactivation. However, there is still limited evidence to support the EMT programme functional contribution to metastasis, which keeps a key question still open whether we should target EMT programme of cancer cells. Answers to that question might help develop an anticancer strategy or guide new directions for anticancer metastasis therapy.

Identification and validation of prognostic autophagy-related genes associated with immune microenvironment in human gastric cancer

Autophagy-related genes (ATGs) play critical roles in tumorigenesis and progression in gastric cancer (GC). The present study aimed to identify immune-based prognostic ATGs and verify their functions in tumor immune microenvironment (TIME) in GC. Macrophage infiltration was found to negatively correlate with prognosis in GC patients. After stratifying by infiltration levels of macrophages, we screened The Cancer Genome Atlas and Human Autophagy Database to identify the differentially expressed ATGs (DE-ATGs). Of 1,433 differentially expressed genes between the two groups, seven genes qualified as DE-ATGs. Of these, CXCR4, DLC1, and MAP1LC3C, exhibited strong prognostic prediction ability in Kaplan-Meier survival–log-rank test. High expression of these genes correlated with increased occurrence of advanced grade 3 tumors and poor prognoses. Furthermore, GSEA indicated that they were significantly associated with oncogenic and immune-related pathways. The comprehensive evaluation of TIME via GEPIA, ESTIMATE, CIBERSORT, and TIMER suggested that the three DE-ATGs were closely associated with immune condition, both in terms of immune cells and immune scores. Thus, the outcome of this study may aid in better understanding of the ATGs and their interaction with the immune microenvironment, which would allow the development of novel inhibitors, personalized treatment, and immunotherapy in gastric cancer.

Characteristics of immunophenotypes and immunological in tumor microenvironment and analysis of immune implication of CXCR4 in gastric cancer

The formation of gastric cancer (GC) is a complicated process involving multiple factors and multiple steps. The tumor–immune microenvironment is essential for the growth of GC and affects the prognosis of patients. We performed multiple machine learning algorithms to identify immunophenotypes and immunological characteristics in GC patients’ information from the TCGA database and extracted immune genes relevance of the GC immune microenvironment. C-X-C motif chemokine receptor 4 (CXCR4), belongs to the C-X-C chemokine receptor family, which can promote the invasion and migration of tumor cells. CXCR4 expression is significantly correlated to metastasis and the worse prognosis. In this work, we assessed the condition of immune cells and identified the connection between CXCR4 and GC immune microenvironment, as well as the signaling pathways that mediate the immune responses involved in CXCR4. The work showed the risk scores generated by CXCR4-related immunomodulators could distinguish risk groups consisting of differential expression genes and could use for the personalized prognosis prediction. The findings suggested that CXCR4 is involved in tumor immunity of GC, and CXCR4 is considered as a potential prognostic biomarker and immunotherapy target of GC. The prognostic immune markers from CXCR4-associated immunomodulators can independently predict the overall survival of GC.

CXCR2 Receptor: Regulation of Expression, Signal Transduction, and Involvement in Cancer

Chemokines are a group of about 50 chemotactic cytokines crucial for the migration of immune system cells and tumor cells, as well as for metastasis. One of the 20 chemokine receptors identified to date is CXCR2, a G-protein-coupled receptor (GPCR) whose most known ligands are CXCL8 (IL-8) and CXCL1 (GRO-α). In this article we present a comprehensive review of literature concerning the role of CXCR2 in cancer. We start with regulation of its expression at the transcriptional level and how this regulation involves microRNAs. We show the mechanism of CXCR2 signal transduction, in particular the action of heterotrimeric G proteins, phosphorylation, internalization, intracellular trafficking, sequestration, recycling, and degradation of CXCR2. We discuss in detail the mechanism of the effects of activated CXCR2 on the actin cytoskeleton. Finally, we describe the involvement of CXCR2 in cancer. We focused on the importance of CXCR2 in tumor processes such as proliferation, migration, and invasion of tumor cells as well as the effects of CXCR2 activation on angiogenesis, lymphangiogenesis, and cellular senescence. We also discuss the importance of CXCR2 in cell recruitment to the tumor niche including tumor-associated neutrophils (TAN), tumor-associated macrophages (TAM), myeloid-derived suppressor cells (MDSC), and regulatory T (T_reg) cells.

CXCL1: Gene, Promoter, Regulation of Expression, mRNA Stability, Regulation of Activity in the Intercellular Space

CXCL1 is one of the most important chemokines, part of a group of chemotactic cytokines involved in the development of many inflammatory diseases. It activates CXCR2 and, at high levels, CXCR1. The expression of CXCL1 is elevated in inflammatory reactions and also has important functions in physiology, including the induction of angiogenesis and recruitment of neutrophils. Due to a lack of reviews that precisely describe the regulation of CXCL1 expression and function, in this paper, we present the mechanisms of CXCL1 expression regulation with a special focus on cancer. We concentrate on the regulation of CXCL1 expression through the regulation of CXCL1 transcription and mRNA stability, including the involvement of NF-κB, p53, the effect of miRNAs and cytokines such as IFN-γ, IL-1β, IL-17, TGF-β and TNF-α. We also describe the mechanisms regulating CXCL1 activity in the extracellular space, including proteolytic processing, CXCL1 dimerization and the influence of the ACKR1/DARC receptor on CXCL1 localization. Finally, we explain the role of CXCL1 in cancer and possible therapeutic approaches directed against this chemokine.

CXCR4 promotes the growth and metastasis of esophageal squamous cell carcinoma as a critical downstream mediator of HIF-1α

C–X–C motif chemokine receptor 4 (CXCR4) belongs to the CXC chemokine receptor family, which mediates the metastasis of tumor cells and promotes the malignant development of cancers. However, its biological role and regulatory mechanism in esophageal squamous cell carcinoma (ESCC) remain unclear. Here, we found that CXCR4 expression was associated with lymph node metastasis and a poor prognosis. In vitro and in vivo studies demonstrated that CXCR4 overexpression promoted ESCC cell proliferation, migration, invasion, and survival, whereas silencing CXCR4 induced the opposite effects. Mechanically, HIF‐1α transcriptionally regulates CXCR4 expression by binding to a hypoxia response element in its promoter. HIF‐1α‐induced ESCC cell migration and invasion were reversed by CXCR4 knockdown or treatment with MSX‐122, a CXCR4 antagonist. Collectively, these data revealed that the HIF‐1α/CXCR4 axis plays key roles in ESCC growth and metastasis and indicated CXCR4 as a potential target for ESCC treatment.

Identification of an Immune-Related Long Noncoding RNA Pairs Model to Predict Survival and Immune Features in Gastric Cancer

Background: Gastric cancer (GC) remains one of the most malignant tumors around the world, and an accurate model that reliably predicts survival and therapeutic efficacy is urgently needed. As a novel predictor for prognosis in a variety of cancers, immune-related long noncoding RNA pairs (IRlncRNAPs) have been reported to predict tumor prognosis. Herein, we integrated an IRlncRNAPs model to predict the clinical outcome, immune features, and chemotherapeutic efficacy of GC.

Methods: Based on the GC data obtained from The Cancer Genome Atlas (TCGA) database and the Immunology Database and Analysis Portal (ImmPort), differentially expressed immune-related long noncoding RNAs (DEIRlncRNAs) were identified. Least absolute shrinkage and selection operator (LASSO) regression and Cox regression analysis were used to select the most appropriate overall survival (OS)-related IRlncRNAPs to develop a prognostic signature. The riskScore of each sample was calculated by comparing the long noncoding RNA expression level in each IRlncRNAP. Based on the riskScore for each patient, GC patients were divided into high- and low-risk groups. Then, the correlation of the signature and riskScore with OS, clinical features, immune cell infiltration, immune-related gene (IRG) expression and chemotherapeutic efficacy in GC was analyzed.

Results: A total of 107 DEIRlncRNAs were identified which formed 4297 IRlncRNAPs. Fifteen OS-related IRlncRNAPs were selected to develop a prognostic model. GC patients could be accurately classified into high- and low-risk groups according to the riskScore of the prognostic model. The 1-, 2-, 3-, and 5-year receiver operating characteristic (ROC) curves for the riskScore were drawn and the area under the curve (AUC) values were found to be 0.788, 0.810, 0.825, and 0.868, respectively, demonstrating a high sensitivity and accuracy of this prognostic signature. Moreover, the immune-related riskScore was an independent risk factor. Patients showed a poorer outcome within the high-risk group. In addition, the riskScore was found to be significantly correlated with the clinical features, immune infiltration status, IRG expression, and chemotherapeutic efficacy in GC.

Conclusion: The prognostic model of IRlncRNAPs offers great promise in predicting the prognosis, immune infiltration status, and chemotherapeutic efficacy in GC, which might be helpful for the selection of chemo- and immuno-therapy of GC.

MiR-622 acts as a tumor suppressor to induce cell apoptosis and inhibit metastasis in human prostate cancer

Growing evidence indicating the critical modulator roles of microRNAs (miRNAs) involved in prostate cancer (PCa) metastasis that holds great promise as therapeutic targets. Herein, we transfected the miR-622 mimic into PC3 cells and evaluated the effects of this interference on these tumour cells' growth and the expression of specific metastatic genes. Transfecting of miR-622 mimic and inhibitor, negative control (NC) inhibitor and NC was established using Lipofectamine 2000. The mRNA levels of miR-622 and metastatic genes were evaluated using the qRT-PCR and Western blot. Cytotoxic effects of miR-622 were assessed by MTT. Apoptosis was detected using an ELISA cell death assay kit. miR-622 is down-regulated in PC3 cells. As expected, cell viability effects after transfection were described as miR-622 inhibitor >NC and NC inhibitor >miR-622 mimic (p < .01). Importantly, we showed that transfected miR-622 mimic could enhance the apoptosis of PC3 cells, while transfected miR-622 inhibitor could decrease cell apoptosis (p < .01). Furthermore, miR-622 overexpression could increase significantly down-regulated the MMP2, MMP9, CXCR-4, c-Myc and K-Ras expression levels. Findings demonstrate a novel mechanism by which miR-622 modulates PCa cells' metastasis by targeting metastatic genes. These data confirm the tumour-suppressive function of miR-622 in PCa cells by enhancing apoptosis and reducing metastasis.

An optimized derivative of an endogenous CXCR4 antagonist prevents atopic dermatitis and airway inflammation

Aberrant CXCR4/CXCL12 signaling is involved in many pathophysiological processes such as cancer and inflammatory diseases. A natural fragment of serum albumin, named EPI-X4, has previously been identified as endogenous peptide antagonist and inverse agonist of CXCR4 and is a promising compound for the development of improved analogues for the therapy of CXCR4-associated diseases. To generate optimized EPI-X4 derivatives we here performed molecular docking analysis to identify key interaction motifs of EPI-X4/CXCR4. Subsequent rational drug design allowed to increase the anti-CXCR4 activity of EPI-X4. The EPI-X4 derivative JM#21 bound CXCR4 and suppressed CXCR4-tropic HIV-1 infection more efficiently than the clinically approved small molecule CXCR4 antagonist AMD3100. EPI-X4 JM#21 did not exert toxic effects in zebrafish embryos and suppressed allergen-induced infiltration of eosinophils and other immune cells into the airways of animals in an asthma mouse model. Moreover, topical administration of the optimized EPI-X4 derivative efficiently prevented inflammation of the skin in a mouse model of atopic dermatitis. Thus, rationally designed EPI-X4 JM#21 is a novel potent antagonist of CXCR4 and the first CXCR4 inhibitor with therapeutic efficacy in atopic dermatitis. Further clinical development of this new class of CXCR4 antagonists for the therapy of atopic dermatitis, asthma and other CXCR4-associated diseases is highly warranted.

Identification of potential targets of triptolide in regulating the tumor microenvironment of stomach adenocarcinoma patients using bioinformatics

This study aimed to identify potential pharmacological targets of triptolide regulating the tumor microenvironment (TME) of stomach adenocarcinoma (STAD) patients. A total of 343 STAD cases from The Cancer Genome Atlas (TCGA) were assigned into high- or low-score groups applying Estimation of STromal and Immune cells in MAlignant Tumor tissues using Expression data (ESTIMATE). Hub genes were identified from differentially expressed genes (DEGs) shared by stromal- and immune-related components in the TME of STAD patients using R software. Cox regression analysis was used to identify genes significantly correlated with STAD patient survival. Triptolide target genes were predicted from the Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform (TCMSP). Top 30 genes filtered by Cytohubba from 734 DEGs were screened as hub genes. Forty-two genes were found to be at high risk for STAD prognosis. Thirty-four targets of triptolide were predicted using the TCMSP database. Importantly, C-X-C chemokine receptor type 4 (CXCR4) was identified as a potential target of triptolide associated with the TME in STAD. Analysis of survival highlighted the association between CXCR4 upregulation with STAD progression and poor prognosis. Gene Set Enrichment Analysis (GSEA) confirmed that genes in the CXCR4- upregulated group had significant enrichment in immune-linked pathways. Additionally, triptolide targets were found to be significantly enriched in CXCR4-related chemokine and cancer-related p53 signaling pathways. Molecular docking demonstrated a high affinity between triptolide and CXCR4. In conclusion, CXCR4 may be a therapeutic target of triptolide in the treatment of STAD patients by modulating the TME.

The transcription factor BACH1 at the crossroads of cancer biology: From epithelial-mesenchymal transition to ferroptosis

The progression of cancer involves not only the gradual evolution of cells by mutations in DNA but also alterations in the gene expression induced by those mutations and input from the surrounding microenvironment. Such alterations contribute to cancer cells' abilities to reprogram metabolic pathways and undergo epithelial-to-mesenchymal transition (EMT), which facilitate the survival of cancer cells and their metastasis to other organs. Recently, BTB and CNC homology 1 (BACH1), a heme-regulated transcription factor that represses genes involved in iron and heme metabolism in normal cells, was shown to shape the metabolism and metastatic potential of cancer cells. The growing list of BACH1 target genes in cancer cells reveals that BACH1 promotes metastasis by regulating various sets of genes beyond iron metabolism. BACH1 represses the expression of genes that mediate cell–cell adhesion and oxidative phosphorylation but activates the expression of genes required for glycolysis, cell motility, and matrix protein degradation. Furthermore, BACH1 represses FOXA1 gene encoding an activator of epithelial genes and activates SNAI2 encoding a repressor of epithelial genes, forming a feedforward loop of EMT. By synthesizing these observations, we propose a “two-faced BACH1 model”, which accounts for the dynamic switching between metastasis and stress resistance along with cancer progression. We discuss here the possibility that BACH1-mediated promotion of cancer also brings increased sensitivity to iron-dependent cell death (ferroptosis) through crosstalk of BACH1 target genes, imposing programmed vulnerability upon cancer cells. We also discuss the future directions of this field, including the dynamics and plasticity of EMT.

Clinical significance and prognostic role of an immune-related gene signature in gastric adenocarcinoma

Limited progress has been made in the treatment of gastric adenocarcinoma (GAC) in recent years, but the potential of immunotherapy in GAC is worthy of consideration. The purpose of this study was to develop a reliable, personalized signature based on immune genes to predict the prognosis of GAC. Here, we identified two groups of patients with significantly different prognoses by performing unsupervised clustering analysis of The Cancer Genome Atlas (TCGA) database based on 881 immune genes. The immune signature was constructed with a training set composed of 350 GAC samples from the TCGA and subsequently validated with 431 samples from GSE84437, 432 samples from GSE26253, and 145 GAC samples from real-time quantitative reverse transcription polymerase chain reaction data. This classification system can also be used to predict prognosis in different clinical subgroups. Further analysis suggested that high-risk patients were characterized by low immune scores, distinctive immune cell proportions, different immune checkpoint profiles, and a low tumor mutational burden. Ultimately, the signature was identified as an independent prognostic factor. In general, the signature can accurately predict recurrence and overall survival in patients with GAC and may serve as a powerful prognostic tool to further optimize cancer immunotherapy.

Dexamethasone suppresses immune evasion by inducing GR/STAT3 mediated downregulation of PD-L1 and IDO1 pathways

T cell exhaustion plays critical roles in tumor immune evasion. Novel strategies to suppress immune evasion are in urgent need. We aimed to identify potential compounds to target T cell exhaustion and increase response to immune checkpoint inhibitors (ICIs). Differentially expressed genes (DEGs) were identified between tumors with different immune evasion potential by comparing the transcriptome data. DEGs were then analyzed in the Connectivity Map (CMap) platform to identify potential compounds to increase response to ICIs. Gene set enrichment analysis, LDH release assay, Chromatin immunoprecipitation (ChIP), and Co-IP were performed to explore the potential mechanisms in vitro. Patients derived organoids and humanized xenograft mouse model were utilized to validate the finding ex vivo and in vivo. We identified 25 potential compounds that may play critical roles in regulating tumor immune evasion. We further pinpointed a specific compound, dexamethasone, which shows potent anti-tumor effect in multiple cancer cell lines when cocultured with T cells. Dexamethasone can suppress T cell exhaustion by decreasing the activity of two immune checkpoints simultaneously, including PD-L1 and IDO1. Functional study shows dexamethasone can increase the sensitivity of ICIs in coculture system, 3D organoid model and humanized mouse model. Mechanism study shows dexamethasone mediated transcriptional suppression of PD-L1 and IDO1 depends on the nuclear translocation of GR/STAT3 complex. These findings demonstrate dexamethasone can suppress immune evasion by inducing GR/STAT3 mediated downregulation of PD-L1 and IDO1 pathways.

CXCR4 is a prognostic marker that inhibits the invasion and migration of gastric cancer by regulating VEGF expression

Metastasis is the main cause of poor prognosis of patients with gastric cancer (GC). Thus, current research is focused on identifying biomarkers that can predict the prognosis of patients with GC. C-X-C motif chemokine receptor 4 (CXCR4) and vascular endothelial growth factor (VEGF) have been reported to play important roles in different types of malignancies; however, their role in the prognosis of GC remains unknown. The present study aimed to investigate the potential role of CXCR4 and VEGF in predicting the prognosis of patients with GC. Immunohistochemistry analysis was performed to analyze the expression levels of CXCR4 and VEGF in a GC tissue microarray containing GC tissues and adjacent normal tissues. The association between CXCR4 or VEGF expression levels and the clinicopathological characteristics or survival outcomes were assessed. Furthermore, Transwell and wound healing assays were performed to determine the cell invasive and migratory abilities in vitro. The results demonstrated that CXCR4 promoted AGS cell invasion and migration by regulating VEGF expression. In addition, CXCR4 and VEGF expression levels were significantly upregulated in GC tissues compared with adjacent normal tissues, which was associated with a poorer overall survival (OS). Cox regression analysis demonstrated that both upregulated CXCR4 and VEGF expression were independent negative biomarkers of OS. To the best of our knowledge, the present study was the first to discover that CXCR4 and VEGF exert synergistic roles as efficient prognostic indicators for patients with GC.

Human Gastric Cancer Stem Cell (GCSC) Markers Are Prognostic Factors Correlated With Immune Infiltration of Gastric Cancer

The prognosis of patients with gastric cancer (GC) is still unsatisfying. Numerous markers of gastric cancer stem cells (GCSCs) have been identified and were thought to be related to cancer aggressiveness. However, the roles of GCSC markers in GC patients’ prognosis and immune infiltration remain unknown. Expression of GCSC markers was analyzed using Oncomine and Gene Expression Profiling Interactive Analysis (GEPIA). Their associations with clinicopathological parameters were analyzed using UALCAN and LinkedOmics. Alternations and protein expression of GCSC markers were analyzed by cBioPortal and the Human Protein Atlas databases, respectively. The prognostic significance of GCSC markers was evaluated using Kaplan-Meier plotter. Correlations between the expression of GCSC markers and immune infiltration along with biomarkers of tumor-infiltrating immune cells (TIICs) were assessed combined Tumor Immune Estimation Resource and GEPIA. GeneMANIA was used to discover the interactive genes of GCSC markers, and enrichment analysis was performed using Database for Annotation, Visualization, and Integrated Discovery server. We identified six GCSC markers significantly up-expressed in GC, compared with normal stomach tissues. Among them, the overexpression of ICAM1, THY1, and CXCR4 significantly indicated adverse, while EPCAM indicated beneficial clinicopathological features of GC patients. The up-regulation of CXCR4 showed unfavorable prognostic significance, whereas EPCAM and TFRC showed the opposite. The six GCSC markers were all correlated with the infiltration and activation of distinct TIICs. Especially, ICAM1, THY1, and CXCR4 showed strongly positive correlations with tumor-associated macrophages. Besides, chemokine, Toll-like receptor, NF-kappa B, and HIF-1 signaling pathways might be involved in the regulation of GCSC markers on cancer development. This study proposed that GCSC markers might be promising targets of GC treatment to weaken cancer stem-like properties and strengthen anticancer immunity.

Analysis of Gastric Cancer Transcriptome Allows the Identification of Histotype Specific Molecular Signatures With Prognostic Potential

Gastric cancer is the fifth most common malignancy but the third leading cause of cancer-associated mortality worldwide. Therapy for gastric cancer remain largely suboptimal making the identification of novel therapeutic targets an urgent medical need. In the present study we have carried out a high-throughput sequencing of transcriptome expression in patients with gastric cancers. Twenty-four patients, among a series of 53, who underwent an attempt of curative surgery for gastric cancers in a single center, were enrolled. Patients were sub-grouped according to their histopathology into diffuse and intestinal types, and the transcriptome of the two subgroups assessed by RNAseq analysis and compared to the normal gastric mucosa. The results of this investigation demonstrated that the two histopathology phenotypes express two different patterns of gene expression. A total of 2,064 transcripts were differentially expressed between neoplastic and non-neoplastic tissues: 772 were specific for the intestinal type and 407 for the diffuse type. Only 885 transcripts were simultaneously differentially expressed by both tumors. The per pathway analysis demonstrated an enrichment of extracellular matrix and immune dysfunction in the intestinal type including CXCR2, CXCR1, FPR2, CARD14, EFNA2, AQ9, TRIP13, KLK11 and GHRL. At the univariate analysis reduced levels AQP9 was found to be a negative predictor of 4 years survival. In the diffuse type low levels CXCR2 and high levels of CARD14 mRNA were negative predictors of 4 years survival. In summary, we have identified a group of genes differentially regulated in the intestinal and diffuse histotypes of gastric cancers with AQP9, CARD14 and CXCR2 impacting on patients' prognosis, although CXCR2 is the only factor independently impacting overall survival.

Eleven immune-gene pairs signature associated with TP53 predicting the overall survival of gastric cancer: a retrospective analysis of large sample and multicenter from public database

Background

Growing attention have been paid to the relationship between TP53 and tumor immunophenotype, but there are still lacking enough search on the field of gastric cancer (GC).

Materials and methods

We identified differential expressed immune-related genes (DEIRGs) between the TP53-altered GC samples (n = 183) and without TP53-altered GC samples (n = 192) in The Cancer Genome Atlas and paired them. In the TCGA cohort (n = 350), a risk score was determined through univariate and multivariate cox regression and Lasso regression analysis. Patients were divided into two groups, high-risk and low-risk, based on the median risk score. Four independent cohorts (GSE84437,n = 431; GSE62254, n = 300; GSE15459, n = 191; GSE26901, n = 100) from the Gene Expression Omnibus (GEO) database were used to validate the reliability and universal applicability of the model.

Results

The signature contained 11 gene pairs showed good performance in predicting progression-free survival (PFS), disease-free survival (DFS), disease special survival (DSS), and the overall survival (OS) for GC patients in the TCGA cohort. The subgroup analysis showed that the signature was suitable for GC patients with different characteristics. The signature could capable of distinguish GC patients with good prognosis and poor prognosis in all four independent external validation cohorts. The high- and low-risk groups differed significantly in the proportion of several immune cell infiltration, especially for the T cells memory resting, T cells memory activated and follicular helper, and Macrophage M0, which was also related to the prognosis of GC patients.

Conclusion

The present work proposed an innovative system for evaluating the prognosis of gastric cancer. Considering its stability and general applicability, which may become a widely used tool in clinical practice.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-021-02846-x.

Mycobacterial infection-induced miR-206 inhibits protective neutrophil recruitment via the CXCL12/CXCR4 signalling axis

Pathogenic mycobacteria actively dysregulate protective host immune signalling pathways during infection to drive the formation of permissive granuloma microenvironments. Dynamic regulation of host microRNA (miRNA) expression is a conserved feature of mycobacterial infections across host-pathogen pairings. Here we examine the role of miR-206 in the zebrafish model of Mycobacterium marinum infection, which allows investigation of the early stages of granuloma formation. We find miR-206 is upregulated following infection by pathogenic M. marinum and that antagomir-mediated knockdown of miR-206 is protective against infection. We observed striking upregulation of cxcl12a and cxcr4b in infected miR-206 knockdown zebrafish embryos and live imaging revealed enhanced recruitment of neutrophils to sites of infection. We used CRISPR/Cas9-mediated knockdown of cxcl12a and cxcr4b expression and AMD3100 inhibition of Cxcr4 to show that the enhanced neutrophil response and reduced bacterial burden caused by miR-206 knockdown was dependent on the Cxcl12/Cxcr4 signalling axis. Together, our data illustrate a pathway through which pathogenic mycobacteria induce host miR-206 expression to suppress Cxcl12/Cxcr4 signalling and prevent protective neutrophil recruitment to granulomas.

CXCL5/CXCR2 axis in tumor microenvironment as potential diagnostic biomarker and therapeutic target

The components of the tumor microenvironment (TME) in solid tumors, especially chemokines, are currently attracting much attention from scientists. C-X-C motif chemokine ligand 5 (CXCL5) is one of the important chemokines in TME. Overexpression of CXCL5 is closely related to the survival time, recurrence and metastasis of cancer patients. In TME, CXCL5 binds to its receptors, such as C-X-C motif chemokine receptor 2 (CXCR2), to participate in the recruitment of immune cells and promote angiogenesis, tumor growth, and metastasis. The CXCL5/CXCR2 axis can act as a bridge between tumor cells and host cells in TME. Blocking the transmission of CXCL5/CXCR2 signals can increase the sensitivity and effectiveness of immunotherapy and slow down tumor progression. CXCL5 and CXCR2 are also regarded as biomarkers for predicting prognosis and molecular targets for customizing the treatment. In this review, we summarized the current literature regarding the biological functions and clinical significance of CXCL5/CXCR2 axis in TME. The possibility to use CXCL5 and CXCR2 as potential prognostic biomarkers and therapeutic targets in cancer is also discussed.

High expression of regulator of G-protein signalling 1 is associated with the poor differentiation and prognosis of gastric cancer

Emerging evidence has highlighted that immune and stromal cells form the majority of the tumour microenvironment (TME), which plays important roles in tumour progression. The present study aimed to screen vital prognostic genes associated with the TME in gastric cancer (GC). The ESTIMATE algorithm was applied to calculate TME-related scores, and the relationship between clinicopathological variables and these scores was analysed. Heatmaps and Venn plots were then used to visualize and screen differentially expressed genes. Furthermore, functional enrichment analysis was performed, and a protein-protein interaction network was constructed. Kaplan-Meier curves were generated to evaluate survival differences for each hub gene. Reverse transcription quantitative PCR was employed to evaluate the expression of the three hub genes in the validation cohort. The association between gene expression, clinicopathological variables and survival was also evaluated. Higher stromal scores were associated with worse outcomes in patients with GC. In addition, higher scores were significantly associated with a higher tumour grade, American Joint Committee on Cancer stage and T stage with regard to immune scores, stromal scores and ESTIMATE scores, respectively. In total, 644 upregulated intersecting genes and 126 downregulated genes were identified. Moreover, 71 TME-associated hub genes were identified. Batch survival analysis revealed that higher expression of CXCR4, PTGFR and RGS1 was significantly associated with worse outcome. Subsequently, the relationship between high expression of RGS1 and poor prognosis was verified, and high expression of RGS1 was associated with poor differentiation. In conclusion, it was found that compared with immune cells, stromal cells may play a more important role in the prognosis of patients with GC. In addition, the influence of RGS1 expression on survival in GC patients was identified and verified, and high expression of RGS1 was found to be associated with a low differentiation degree of GC.

Long non-coding RNA DUXAP8 promotes the cell proliferation, migration, and invasion of papillary thyroid carcinoma via miR-223-3p mediated regulation of CXCR4

Papillary thyroid carcinoma (PTC) is a differentiated type of thyroid malignancy with a high incidence. Long non-coding RNA (lncRNA) DUXAP8 has been reported to participate in the proliferation, migration, and invasion of several cancer types. However, its association with PTC has not yet been reported. The current study aimed to investigate the role of DUXAP8 in PTC and revealed the underlying mechanisms. The expression of DUXAP8 was knocked down in two PTC cell lines and the effects of DUXAP8 on the PTC biological behavior were examined by cell counting kit-8 (CCK-8), wound healing, and transwell invasion assays. Luciferase reporter assay was used to detect the binding activity between miR-223-3p and DUXAP8. We found that knockdown of DUXAP8 inhibited the proliferation, migration, and invasion of PTC cells. DUXAP8 could sponge miR-223-3p through the specific binding site. CXCR4 was a target of miR-223-3p. The malignant phenotypes of the PTC cells were suppressed by the over-expression of miR-223-3p. Moreover, miR-223-3p inhibition or CXCR4 over-expression partly restored the proliferation, migration, and invasion activities of DUXAP8-downregulated PTC cells. The results evidenced that DUXAP8 acted as an oncogene in PTC, these effects seemed to partly dependent on the miR-223-3p/CXCR4 axis.

Long Noncoding RNA LINC00963 Promotes CDC5L-Mediated Malignant Progression in Gastric Cancer

Background

Gastric cancer (GC) is a common cancer with high incidence and mortality worldwide. In recent years, accumulating evidence has shown that long noncoding RNAs (lncRNAs) exert critical roles in the development and progression of cancer by acting as a tumor initiator or suppressor. LINC00963 is a newly reported lncRNA related to cancer, and its role in GC remains unclear.

Materials and Methods

The expression levels of LINC00963, miR-612, and cell division cycle 5-like protein (CDC5L) were measured using quantitative real-time PCR or Western blot. The biological functions of LINC00963, miR-612, and CDC5L in GC cells were analyzed by transwell and proliferation experiments. The expression of CDC5L in patients with GC was evaluated using the Oncomine database. Bone marrow-derived dendritic cells (DCs) were derived from C57BL/6 mice.

Results

LINC00963 expression was higher in GC tissues than in adjacent normal tissues. Similar results were found in GC cell lines and normal human gastric epithelial cells. Upregulation of LINC00963 was related to the poor prognosis of patients with GC. Knockdown of LINC00963 inhibited the proliferation, invasion, and metastasis but promoted the apoptosis of GC cells. Furthermore, silencing of LINC00963 in GC cells significantly suppressed the tumor growth of GC. Bioinformatics analysis indicated that LINC00963 could target miR-612 by functioning as a competing endogenous RNA. The expression of miR-612 decreased in GC tissues and cell lines. Meanwhile, LINC00963 expression was negatively associated with miR-612. CDC5L was a direct target of miR-612. miR-612 suppressed the expression of CDC5L in GC tissues and cells. Moreover, LINC00963 inhibited the differentiation and maturation of DCs by regulating miR-612 expression in DCs.

Conclusion

LINC00963 promoted the progression of GC by competitively binding to miR-612 to regulate the expression of CDC5L and mediated DC-related anti-tumor immune response. Thus, targeting LINC00963 may be a promising therapeutic strategy for GC.

Upregulation of Serine Proteinase Inhibitor Clade B Member 3 (SERPINB3) Expression by Stromal Cell-Derived Factor (SDF-1)/CXCR4/Nuclear Factor kappa B (NF-κB) Promotes Migration and Invasion of Gastric Cancer Cells

BACKGROUND Serine proteinase inhibitor clade B member 3 (SERPINB3) is a neutral glycoprotein. Its overexpression is related to the promotion of cell proliferation and activation via the nuclear factor kappa B (NF-kappaB) pathway in several tumors. Whether it can participate in stromal cell-derived factor (SDF-1)/NF-kappaB-induced metastasis of gastric cancer has not been reported. MATERIAL AND METHODS We analyzed the ability of SDF-1 to induce migration and invasion in vitro by knocking down the expression of SERPINB3 with siRNAs in gastric cancer cells. We also explored the effects of a CXCR4 antagonist and NF-kappaB inhibitor on SERPINB3 expression. We verified the effect of SERPINB3 on prognosis in gastric cancer specimens by immunohistochemistry. RESULTS In vitro experiments confirmed that SDF-1 upregulated the expression of SERPINB3 and promoted metastasis in gastric cancer cells. This phenomenon was reversed by knockdown of SERPINB3, a chemokine receptor 4 (CXCR4) antagonist, and an NF-kappaB inhibitor, which downregulated the expression of SERPINB3. In patients with gastric cancer, a significant positive correlation was observed between CXCR4 and SERPINB3 expression (r=0.222, P=0.029). Moreover, double positivity for SERPINB3 and CXCR4 was certified to be an independent prognostic factor (HR=3.332, P<0.001). CXCR4-positive patients who also expressed SERPINB3 were inclined to suffer from lymph node metastasis, confirming that SERPINB3 is a downstream molecule of CXCR4. CONCLUSIONS In vitro and pathological results showed that SDF-1/CXCR4 activated the NF-kappaB pathway and upregulated SERPINB3 to facilitate the migration and invasion of gastric cancer cells.

Long non-coding RNA Loc490 inhibits gastric cancer cell proliferation and metastasis by upregulating RNA-binding protein Quaking

Gastric cancer (GC) is one of the most common malignant tumor types worldwide. Long non-coding RNAs (lncRNAs) have important epigenetic effects, including altering the proliferation and metastasis of malignant tumors. We used gene chip technology to search for lncRNAs that were differentially expressed in GC and metastatic lymph node tissues compared with adjacent normal tissues. The lncRNA Loc490 and the RNA-binding protein Quaking (QKI) were downregulated in GC tissues and lymph node metastases compared with normal tissues, and the levels of these two genes correlated positively with one another. Loc490 expression correlated negatively with lymph node metastasis and vein/nerve invasion, while it correlated positively with overall and disease-free survival. In vitro, Loc490 post-translationally enhanced the expression of QKI and suppressed the expression of epithelial-mesenchymal transition-related molecules. Overexpression of Loc490 inhibited GC cell proliferation, invasion and metastasis and exerted strong antitumor effects in vivo, while silencing of QKI antagonized these effects. A potential binding site between Loc490 and QKI was detected through bioinformatics analysis and confirmed through RNA immunoprecipitation and mutant analyses. Our results suggest that lncRNA Loc490 inhibits GC cell proliferation and metastasis by upregulating RNA-binding protein QKI.

Positive Cross-Talk Between CXC Chemokine Receptor 4 (CXCR4) and Epidermal Growth Factor Receptor (EGFR) Promotes Gastric Cancer Metastasis via the Nuclear Factor kappa B (NF-kB)-Dependent Pathway

BACKGROUND Previous studies have established cross-talk between CXC chemokine receptor 4 (CXCR4) and epidermal growth factor receptor (EGFR) in gastric cancer, however, the effect of dual CXCR4/EGFR tumor status on patient survival and mechanisms regulating expression has yet to be investigated. MATERIAL AND METHODS A total of 56 gastric cancer patients were recruited to reveal the relationship between CXCR4 and EGFR expression, and the clinic-pathological features of samples were investigated by immunohistochemical staining. Two gastric cancer cell lines were treated with CXCL12 or EGF, and expression levels of CXCR4 and EGFR were detected by reverse-transcription-polymerase chain reaction and western blotting. Cells were treated with an NF-kappaB pathway inhibitor to investigate its role in the regulation of CXCL12 or EGF-mediated CXCR4 and EGFR expression and migration ability. RESULTS The results show that CXCL12 upregulated CXCR4 and EGFR. Similarly, EGF could induce the expression of CXCR4 and contribute to gastric cancer cell metastasis. In addition, both CXCL12 and EGF could induce the activation of IKKalphaß and P65. Conversely, suppression of the NF-kappaB pathway remarkably decreased the expression of CXCR4/EGFR and migration ability induced by EGF or CXCL12. Furthermore, a significantly positive correlation between CXCR4 and EGFR expression was observed in gastric cancer patient tissues (r=0.372, P=0.005). Samples expressing both receptors had significantly poorer patient prognosis than other patient groups (P=0.002). CONCLUSIONS Our results showed that the CXCL12/CXCR4 and EGF/EGFR axis can regulate the expression of each other through the NF-kappaB pathway to promote metastasis. These data suggested that simultaneous inhibition of EGFR and CXCR4 may be a potential therapeutic strategy in gastric cancer.

FYN promotes gastric cancer metastasis by activating STAT3-mediated epithelial-mesenchymal transition

Gastric cancer is one of the most lethal cancers worldwide. FYN, a gene that is differentially expressed in gastric cancer, is considered a critical metastasis regulator in several solid tumors, but its role in gastric cancer is still unclear. This study aimed to evaluate the role of FYN and test whether FYN promotes migration and invasion of gastric cancer cells in vitro and in vivo via STAT3 signaling. FYN was overexpressed in gastric cancer and positively correlated with metastasis. FYN knockdown significantly decreased cancer cell migration and invasion, whereas FYN overexpression increased cancer migration and invasion. Genetic inhibition of FYN decreased the number of metastatic lung nodules in vivo. Several epithelial-mesenchymal transition markers were positively correlated with FYN expression, indicative of FYN involvement in this transition. Furthermore, gene set enrichment analysis of a Cancer Genome Atlas dataset revealed that the STAT3 signaling pathway was positively correlated with FYN expression. STAT3 inhibition reversed the FYN-mediated epithelial-mesenchymal transition and suppressed metastasis. In conclusion, FYN promotes gastric cancer metastasis possibly by activating STAT3-mediated epithelial mesenchymal transition and may be a novel therapeutic target for gastric cancer.

Exposure to low dose ZnO nanoparticles induces hyperproliferation and malignant transformation through activating the CXCR2/NF-κB/STAT3/ERK and AKT pathways in colonic mucosal cells

As ZnO nanoparticles have been applied in many fields, their biological risks on human health, of course, are worthy of our attention. Whether ZnO NPs have the risk and how colonic cells respond to the invaded ZnO NPs are still unknown. Herein, we evaluated the biological effects of ZnO NPs on colonic mucosal cells by in vitro and in vivo methods. IMCE cells, with APC mutation but phenotypically normal, demonstrated hyperproliferation through activating the CXCR2/NF-κB/STAT3/ERK and AKT pathways when exposed to ZnO NPs for 24 h. Long-term exposure of ZnO NPs resulted in the malignant transformation of IMCE cells, showing the morphological changes, anchorage-independent cell growth ability. Importantly, IMCE cells exposed to ZnO NPs subcutaneously grew and induced tumorigenesis in nude mice. In conclusion, exposure of ZnO NPs could induce malignant transformation of colonic mucosal cells through the CXCR2/NF-κB/STAT3/ERK and AKT pathways. We suggest that it was necessary to consider using the precautionary principle for gastrointestinal contact nanomaterials.

Identification of four genes associated with cutaneous metastatic melanoma

Background

Cutaneous melanoma is an aggressive cancer with increasing incidence and mortality rates worldwide. Metastasis is one of the primary elements that influence the prognosis of patients with cutaneous melanoma. This study aims to clarify the potential mechanism underlying the low survival rate of metastatic melanoma and to search for novel target genes to improve the survival rate of patients with metastatic tumors.

Methods

Gene expression dataset and clinical data were downloaded from The Cancer Genome Atlas portal. Differentially expressed genes (DEGs) were identified, and their functions were studied through gene ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses. Survival and multivariate Cox regression analyses were used to screen out candidate genes that could affect the prognosis of patients with metastatic melanoma.

Results

After a series of comprehensive statistical analysis, 464 DEGs were identified between primary tumor tissues and metastatic tissues. Survival and multivariate Cox regression analyses revealed four vital genes, namely, POU2AF1, ITGAL, CXCR2P1, and MZB1, that affect the prognosis of patients with metastatic melanoma.

Conclusion

This study provides a new direction for studying the pathogenesis of metastatic melanoma. The genes related to cutaneous metastatic melanoma that affect the overall survival time of patients were identified.

Chemokine receptor 4 expression is correlated with the occurrence and prognosis of gastric cancer

Gastric cancer (GC) is a common tumor with a low 5-year survival rate. The chemokine receptor 4 (CXCR4) protein contributes to the progression and prognosis of GC, but the relationship between CXCR4 and immune infiltration, somatic copy number alteration (SCNA), tumor purity, tumor mutation burden (TMB), cytolytic activity (CYT), and drug sensitivity in GC is poorly understood. This study aimed to systematically explore the role of CXCR4 in GC. Microarray and RNA-seq data were collected from the Gene Expression Omnibus and The Cancer Genome Atlas. Our analysis shows that CXCR4 is correlated with various types of immune cells. Patients with high CXCR4 expression had a higher fraction of B cells and CD8+ T cells, and a lower fraction of CD4+ T cells. In addition, high CXCR4 expression was associated with more advanced tumor stage, worse prognosis and higher stromal score, immune score, and cytolytic activity (P < 0.05). High CXCR4 expression also correlated with lower tumor purity and TMB. In summary, our analyses suggest that CXCR4 may affect the progression and prognosis of GC by influencing immune infiltration, TMB, CYT, tumor purity, and drug sensitivity.

LncRNA UCA1 promotes cisplatin resistance in gastric cancer via recruiting EZH2 and activating PI3K/AKT pathway

Background: Drug resistance of cancer cells is one of the major causes of chemotherapy failure. Recently research demonstrated that long non-coding RNA Urothelial cancer associated 1 (UCA1) could promote tumor cisplatin resistance. In this study, we aim to investigate the role of UCA1 in the cisplatin treatment of gastric cancer and its underlying mechanism. Methods: Cell counting kit-8 (CCK-8) assay and apoptosis assay were used to detect the effects of different doses of cisplatin on the proliferation and apoptosis of gastric cancer. We examined the expression relationship between the Enhancer of Zeste Homologue 2 (EZH2) and UCA1 by quantitative Real-time polymerase chain reaction (qRT-PCR) and western blot analysis. Western blot analysis was also performed to detect the expression levels of apoptosis-related proteins, EZH2 and key genes in PI3K/AKT signaling pathway, RIP and RNA pull down assays were performed to explore the interaction between UCA1 and EZH2. Results: We demonstrated that higher the UCA1 expression levels in GC tissues correlated with the poorer the prognosis of patients according to the TCGA database, the GEO database. Moreover, overexpression of UCA1 promotes GC cell proliferation and inhibits cisplatin-induced apoptosis. Knockdown of UCA1 showed the opposite results. Besides, UCA1 exerted its function through interacting with EZH2 and regulates EZH2 expression, knockdown of EZH2 decreased cisplatin resistance of GC cells. Hence, UCA1 promotes cisplatin resistance of GC via recruiting EZH2 and activating PI3K/AKT pathway. Conclusion: Our research revealed the lncRNA UCA1 promoted the cisplatin resistance of GC by recruiting EZH2 and activating PI3K/AKT pathway to modulate cell apoptosis, indicating treatments targeting UCA1 or EZH2 might provide meaningful therapeutic strategies for cisplatin-resistance GC patients.

HNF4A-AS1/hnRNPU/CTCF axis as a therapeutic target for aerobic glycolysis and neuroblastoma progression

BACKGROUND

Aerobic glycolysis is a hallmark of metabolic reprogramming that contributes to tumor progression. However, the mechanisms regulating expression of glycolytic genes in neuroblastoma (NB), the most common extracranial solid tumor in childhood, still remain elusive.

METHODS

Crucial transcriptional regulators and their downstream glycolytic genes were identified by integrative analysis of a publicly available expression profiling dataset. In vitro and in vivo assays were undertaken to explore the biological effects and underlying mechanisms of transcriptional regulators in NB cells. Survival analysis was performed by using Kaplan-Meier method and log-rank test.

RESULTS

Hepatocyte nuclear factor 4 alpha (HNF4A) and its derived long noncoding RNA (HNF4A-AS1) promoted aerobic glycolysis and NB progression. Gain- and loss-of-function studies indicated that HNF4A and HNF4A-AS1 facilitated the glycolysis process, glucose uptake, lactate production, and ATP levels of NB cells. Mechanistically, transcription factor HNF4A increased the expression of hexokinase 2 (HK2) and solute carrier family 2 member 1 (SLC2A1), while HNF4A-AS1 bound to heterogeneous nuclear ribonucleoprotein U (hnRNPU) to facilitate its interaction with CCCTC-binding factor (CTCF), resulting in transactivation of CTCF and transcriptional alteration of HNF4A and other genes associated with tumor progression. Administration of a small peptide blocking HNF4A-AS1-hnRNPU interaction or lentivirus-mediated short hairpin RNA targeting HNF4A-AS1 significantly suppressed aerobic glycolysis, tumorigenesis, and aggressiveness of NB cells. In clinical NB cases, high expression of HNF4A-AS1, hnRNPU, CTCF, or HNF4A was associated with poor survival of patients.

CONCLUSIONS

These findings suggest that therapeutic targeting of HNF4A-AS1/hnRNPU/CTCF axis inhibits aerobic glycolysis and NB progression.

The LINC00365/SCGB2A1 (Mammaglobin B) Axis Down-Regulates NF-κB Signaling and Is Associated with the Progression of Gastric Cancer

PURPOSE

A lack of early diagnostic biomarkers and therapeutic targets has led to poor prognosis for gastric cancer patients. However, the analysis of cancer-associated genomic data has been shown to be effective in identifying potential markers. Recently, the long non-coding RNA LINC00365 and SCGB2A1 gene (as known as mammaglobin B) were predicted to be co-expressed in gastric cancer based on the Gene Expression Omnibus database. However, their precise role in gastric cancer tumors is still not clear.

METHODS

The expressions of LINC00365 and SCGB2A1 in gastric cancer tissues were investigated using qPCR and their expressions were detected in a gastric cancer tissue microarray by in situ hybridization and immunohistochemical staining. The functions of LINC00365 in BGC-823 and MGC-803 gastric cancer cells were tested using the MTT assay, flow cytometry, colony formation assay, EDU staining, immunofluorescence and luciferase assay.

RESULTS

We found that LINC00365 and SCGB2A1 mRNA were both expressed at low levels in 30 cases of gastric cancer. Gastric cancer tissue microarray analysis indicated that LINC00365 and SCGB2A1 were expressed at low levels in tumor tissue, and low expression of both factors correlated with shorter survival time. Functional studies showed that LINC00365 overexpression significantly inhibited gastric cancer cell viability through the impairment of proliferation rather than the promotion of apoptosis. Furthermore, overexpressed LINC00365 upregulated SCGB2A1 in gastric cancer cell lines. Immuno-fluorescence and luciferase assay analysis indicated that LINC00365 overexpression inhibited the NF-κB pro-survival signaling pathway. Consistent with the effects of LINC00365, SCGB2A1 upregulation also reduced cell survival and inactivated NF-κB.

CONCLUSION

Collectively, our findings revealed that SCGB2A1 may be the target coding protein regulated by LINC00365 in gastric cancer. LINC00365 and SCGB2A1 may function as tumor suppressors and may serve as potential prognostic and therapeutic markers in gastric cancer treatment.

CTHRC1 promotes gastric cancer metastasis via HIF-1α/CXCR4 signaling pathway

Metastasis is the main cause of gastric cancer (GC) related death and the underlying mechanisms still remain unclear. Collagen triple helix repeat containing 1 (CTHRC1) protein is known to be involved in tissue remodeling processes and closely associated with carcinogenesis and metastasis in solid tumors, but the functional role of CTHRC1 and its underlying mechanism with tumor metastasis in GC have not been fully illuminated. In the present study, CTHRC1 was highly expressed in tumor tissues and associated with poor prognosis of GC according to TCGA and GEO database. Functional studies revealed that CTHRC1 overexpression in GC significantly increased cell migration and invasion capacity. However, the promoting effects were abolished subsequent to silencing of CXCR4. In addition, CTHRC1 increased CXCR4 expression through upregulating HIF-1α expression, which eventually contributed to the promotion of cell migration and invasion. Inhibiting HIF-1α expression decreased CXCR4 expression and suppressed cell migration and invasion in GC. These results substantiated our hypothesis that HIF-1α/CXCR4 signaling pathway mediated the promoting effect of CTHRC1 on cell migration and invasion in GC.

Expression of OPN3 in lung adenocarcinoma promotes epithelial-mesenchymal transition and tumor metastasis

Background

Lung adenocarcinoma is the most common pathological lung cancer and an important cause of cancer‐related death. Metastasis is a major underlying reason for poor prognosis of lung adenocarcinoma. Opsin3 (OPN3), a member of the guanine nucleotide‐binding protein‐coupled receptor superfamily, has been identified to affect the apoptosis of hepatoma cells by modulating the phosphorylation of Akt and Bcl2/Bax. However, the expression and role of OPN3 in lung adenocarcinoma remains unclear.

Methods

Opsin3 expression in lung adenocarcinoma tissues was detected by western blot, qPCR, and immunohistochemistry. Changes in cell migration and invasion ability resulting from the change of OPN3 expression level were detected by wound healing and transwell migration assays. Changes in the markers of epithelial‐mesenchymal transformation were detected by western blot and qPCR.

Results

Opsin3 expression in lung adenocarcinoma tissues was higher than that in normal lung tissues. Patients with high expression of OPN3 had lower survival rates. Owing to overexpression of OPN3, the HCC827 cells showed enhanced invasion and migration ability in vitro. Upon decreasing the expression of OPN3, the invasion and migration ability of the A549 cells decreased.

Conclusion

Our study demonstrated for the first time that OPN3 gene enhanced the metastasis in lung adenocarcinoma, and its overexpression promoted epithelial‐mesenchymal transition.

Key points

A significant finding of the study was that OPN3 acted an oncogene in promoting lung adenocarcinoma metastasis. Our study complemented the research on the expression and function of OPN3 in lung adenocarcinoma.

Genetic variations associated with telomere length confer risk of gastric cardia adenocarcinoma

BACKGROUND

Aberrant telomere lengthening is a critical feature of malignant cells. Short leukocyte telomere length (LTL) confers elevated risk of gastric cardia adenocarcinoma (GCA). Multiple genome-wide association studies (GWAS) identified various single-nucleotide polymorphisms (SNPs) associated with LTL in different ethnic populations. However, it remains largely unexplored how these genetic variants are involved in GCA susceptibility.

METHODS

We systematically screened GWAS-identified candidate SNPs and tested the impact of 30 polymorphisms in genes associated with interindividual LTL variation on GCA using two-stage case-control comparisons consisting of 1024 GCA patients and 1118 controls.

RESULTS

We observed that CXCR4 rs6430612, TERT rs10069690, and rs2853676 as well as VPS34 rs2162440 are significantly associated with GCA development. A 0.64-fold decreased risk of GCA is associated with the CXCR4 rs6430612 CT genotype compared with the CC genotype (P = 0.002). On the contrary, the TERT rs10069690 TT genotype carriers had a 1.83-fold increased risk to develop GCA compared to the CC genotype carriers (P = 5.8×10^-6). We also detected a 2.17-fold increased OR for GCA that was associated with the TERT rs2853676 TT genotype (P = 2.6×10^-6). In addition, the odds of having the VPS34 rs2162440 GA genotype in GCA patients were 1.35 compared with the GG genotype (P = 0.002). In stratified analyses, the association between TERT rs10069690 polymorphism and GCA was more pronounced in nonsmokers (P_interaction = 9.7 × 10^-5) and nondrinkers (P_interaction = 4.6 × 10^-5).

CONCLUSIONS

Our results highlight the importance of both LTL and LTL-related genetic variants to GCA predisposition.

THUMP domain containing 2 protein possibly induces resistance to cisplatin and 5-fluorouracil in in vitro human esophageal squamous cell carcinoma cells as revealed by transposon activation mutagenesis

BACKGROUND

Although chemotherapy is a core treatment for esophageal cancer, some patients develop drug resistance. Gene screening with transposons (i.e. mobile genetic elements) is a novel procedure for identifying chemotherapy-resistant genes. Transposon insertion can randomly affect nearby gene expression. By identifying the affected genes, candidate genes can be found. The present study aimed to identify cisplatin (CDDP)/5-fluorouracil (5-FU)-resistant genes in in vitro human esophageal squamous cell carcinoma with transposons.

METHODS

After establishing transposon-tagged cells, we obtained CDDP/5-FU-resistant colonies. A polymerase chain reaction and sequencing were used to identify the transposon inserted site and candidate CDDP/5-FU resistant genes. Focusing on one candidate gene, we confirmed CDDP/5-FU resistance by comparing the IC₅₀ between drug-resistant and wild-type cells. Furthermore, we investigated gene expression by a real-time polymerase chain reaction. Finally, we mediated the candidate gene level with small interfering RNA to confirm the resistance.

RESULTS

Thirty-nine candidate genes for CDDP/5-FU resistance were identified. Nineteen were for CDDP resistance and 27 were for 5-FU resistance. Seven genes, THUMP domain-containing protein 2 (THUMPD2), nuclear factor interleukin-3-regulated protein (NFIL3), tyrosine-protein kinase transmembrane receptor 2 (ROR2), C-X-C chemokine receptor type 4 (CXCR4), thrombospondin type-1 domain-containing protein 2 (THSD7B) alpha-parvin (PARVA) and TEA domain transcription factor 1 (TEAD1), were detected as candidate genes in both colonies. Regarding THUMPD2, its expression was downregulated and knocking down THUMPD2 suggested drug resistance in both drugs.

CONCLUSIONS

Thirty-nine candidate genes were identified with transposons. The downregulation of THUMPD2 was suggested to play a role in multidrug resistance in in vitro esophageal squamous cell carcinoma.

Exosomal miR-196a-1 promotes gastric cancer cell invasion and metastasis by targeting SFRP1

Aim: To investigate the role of exosomal miRNAs on gastric cancer (GC) metastasis. Materials & methods: miRNA expression profiles of exosomes with distinct invasion potentials were analyzed using miRNA microarray and validated by quantitative real-time PCR. In vitro and in vivo experiments assessed the role of exosomal miR-196a-1 in GC's metastasis. Results: High expression level of exosomal miR-196a-1 expression was significantly associated with poor survival in GC. Exosomes that contained miR-196a-1 were secreted from high-invasive GC cells. Ectopic miR-196a-1 expression promoted invasion of low-invasive GC cells by targeting SFRP1. Conclusion: miR-196a-1 was delivered from high-invasive GC into low-invasive GC cells via exosomes and promoted metastasis to the liver in vitro and in vivo.