CXCL16 Promotes Gastric Cancer Tumorigenesis via ADAM10-Dependent CXCL16/CXCR6 Axis and Activates Akt and MAPK Signaling Pathways

Targeting ETHE1 inhibits tumorigenesis in vitro and in vivo by preventing aerobic glycolysis in gastric adenocarcinoma cells

Gastric adenocarcinoma (GAC) is a prevalent form of cancer that frequently displays abnormal metabolism characterized by increased aerobic glycolysis. Therefore, inhibition of glycolysis may exhibit therapeutic potential for the management of advanced or recurrent gastric cancer. Analysis of ethylmalonic encephalopathy protein 1 (ETHE1) expression levels in 30 pairs of cancerous and paracancerous tissues, and 50 tumor tissue sections collected from patients with GAC revealed that ETHE1 expression was upregulated in cancerous tissues compared with in paracancerous tissues. Advanced tumor stage, lymph node metastasis and Tumor-Node-Metastasis stage were associated with high ETHE1 expression. Knockdown of ETHE1 expression in GAC cells resulted in a significant inhibition of cell proliferation and in cell cycle arrest, accompanied by downregulated levels of cyclin D1 and cyclin-dependent kinase 4. ETHE1 knockdown also resulted in increased apoptosis of GAC cells, and increased caspase-3 and caspase-9 activity. Additionally, the expression levels of proteins associated with aerobic glycolysis were downregulated following ETHE1 knockdown, which may reduce glucose consumption, lactic acid production and ATP levels. In the in vivo experiments, suppressed tumor growth and increased tumor cell apoptosis were observed in the xenograft tumor model in animals injected with ETHE1-knockdown GAC cells. In summary, knockdown of ETHE1 inhibited aerobic glycolysis, promoted apoptosis and inhibited tumor cell proliferation in GAC cells. These results highlight ETHE1 as a promising molecular target for the treatment of GAC potentially using an adjuvant to target it, offering a novel approach in the exploration of targeted therapeutic drugs for GAC.

The role of CXC chemokines and receptors in breast cancer

CXC chemokines are a class of cytokines possessing chemotactic properties. Studies indicate that CXC chemokines exhibit dysregulation in miscellaneous cancer categories and are significantly associated with the advancement of tumors. Breast cancer is a commonly diagnosed and fatal cancer among the female population. Breast cancer pathogenesis and progression involve various mechanisms, including invasion, metastasis, angiogenesis, and inflammation. Chemokines and their receptors are involved in all of these processes. The CXC chemokine receptors (CXCRs) and their related ligands have attracted considerable attention due to their multifaceted functions in facilitating and controlling tumor proliferation. CXCRs are expressed by both cancer cells and immune cells, and they play a crucial role in regulating the tumor microenvironment and the immune response. This review aims to assess the potential of CXCRs and CXC chemokines as therapeutic targets or biomarkers for personalized therapy. Additionally, it provides an overview of the current understanding of the expression, function, and prognostic relevance of CXCRs in breast cancer. Furthermore, the challenges and potential prospects pertaining to CXCR investigation in breast cancer are deliberated.

A disintegrin and metallopeptidase domain (ADAM) 12, ADAM 17 mRNA and ADAM10 protein hold potential as biomarkers for detection of early gastric cancer

No biomarker can effectively screen for early gastric cancer (EGC). Players in the A disintegrin and metalloproteinase (ADAM)-natural killer group 2 member D (NKG2D) receptor axis may have a role for that. As a proof-of-concept pilot study, the expression of ADAM8, ADAM9, ADAM10, ADAM12, ADAM17, and major histocompatibility complex (MHC) class I chain-related sequence A (MICA), a ligand for NKG2D, in gastric cancer was investigated in silico using The Cancer Genome Atlas (TCGA) database. Subsequently, the mRNA and protein expression levels of these markers except ADAM8 were tested in blood samples from patients with EGC and healthy controls. In the TCGA data analyses, EGC tissues (n = 57) expressed significantly higher mRNA levels of ADAM8, ADAM9, ADAM10, ADAM12, and ADAM17 than normal tissues (n = 35) (p < 0.005). In human blood sample analyses, ADAM12 (p = 0.0007), ADAM17 mRNA (p < 0.0001) and ADAM10 (p < 0.0017) protein were significantly elevated in patients with EGC (n = 27 for mRNA and n = 25 for protein) compared to the controls (n = 30 for mRNA and n = 26 for protein). Areas under the curves calculated by receiver-operating characteristic analysis for ADAM12, ADAM17 mRNA and ADAM10 protein were 0.7568 (95% confidence interval [CI]: 0.6334 to 0.8802), 0.8062 (95% CI: 0.6889 to 0.9234; p < 0.0001), and 0.8108 (95% CI: 0.6895 to 0.9320; p = 0.0001), respectively. Thus, ADAM12, ADAM17 mRNA and ADAM10 protein levels in peripheral blood could hold potential as biomarkers for screening EGC, and further investigations are required.

CXCR6 expression predicts prognosis and immunotherapeutic benefit in muscle-invasive bladder cancer

Background

Increasing evidence suggests that the CXC chemokine receptor 6 (CXCR6) is involved in tumor progression and the regulation of tumor immunity. However, its role in muscle-invasive bladder cancer (MIBC) remains largely unexplored.

Methods

Data from 391 MIBC patients in the TCGA, 212 patients from GEO, 131 patients from our center, 195 patients in the IMvigor210 cohort, and single-cell RNA sequencing (scRNA-seq) data from 9 bladder cancer patients (GSE222315) were analyzed. Additionally, data from the GEPIA 2, TISCH2, TIMER2.0, and UALCAN platforms were utilized to investigate the prognostic and immunotherapeutic significance of CXCR6 in MIBC.

Results

We observed that CXCR6 expression was significantly reduced in bladder cancer tumors and correlated with tumor stage and grade. Low CXCR6 expression was associated with poor recurrence-free survival (RFS) and overall survival (OS) in the TCGA cohort, a finding validated in both the meta-GEO dataset and our center's cohort. Multivariate analysis confirmed that low CXCR6 expression was an independent predictor of poor OS and RFS. A nomogram incorporating CXCR6 expression and other independent prognostic factors was developed to accurately predict 3- and 5-year OS. Gene set enrichment analysis indicated that immune activation-related pathways were significantly enriched in tumors with high CXCR6 expression. CIBERSORT analysis revealed that CXCR6 expression was positively correlated with CD8+ T cells, CD4+ T cells, activated NK cells, M1 macrophages, and activated dendritic cells in TCGA, findings further validated by TIMER2.0. scRNA-seq data showed that CXCR6 was predominantly expressed in T and NK cells and facilitated T/NK-myeloid interaction via the CXCR6-CXCL16 axis. Importantly, CXCL16+ macrophages and dendritic cells recruited CXCR6+ T and NK cells, which exhibited enhanced cytotoxicity, thereby amplifying anti-tumor immunity. Clinically, in the IMvigor210 immunotherapy cohort, higher CXCR6 expression was associated with improved anti-PD-L1 therapeutic outcomes.

Conclusion

Our findings highlight CXCR6 as a critical biomarker for predicting prognosis and immunotherapeutic response in MIBC.

CXCL16 promotes proliferation of head and neck squamous cell carcinoma by regulating GPX1-mediated antioxidant levels

Numerous studies have demonstrated that the high expression of CXC motif chemokine ligand 16 (CXCL16) in cancer correlates with poor prognosis, as well as tumor cell proliferation, migration, and invasion. While CXCL16 can serve as a tumor biomarker, the underlying mechanism in modulating head and neck squamous cell carcinoma (HNSCC) remains unclear. In this study, the aimed was to investigate the CXCL16 expression in HNSCC and to uncover the potential underlying mechanism. Hereby, we determined the high expression of CXCL16 in The Cancer Genome Atlas (TCGA) database, as well as in tissue samples from patients with HNSCC at our central hospital and from HNSCC cell lines. The results showed that CXCL16 knockdown inhibited the proliferation, migration, and invasion of HNSCC cells. Mechanistically, transcriptome sequencing revealed that CXCL16 may affect HNSCC cell growth by regulating the antioxidant pathway of glutathione peroxidase 1 (GPX1). The reactive oxygen species (ROS) levels were elevated in small interfering CXCL16 (si-CXCL16) cells, which may contribute to the inhibition of cell proliferation, migration, and invasion. Moreover, treatment of cells with the GPX1 inhibitor eldecalcitol (ED-71) revealed that HNSCC cell growth was significantly inhibited in the synergistic group of si-CXCL16 and GPX1 inhibitor compared to the si-CXCL16 group. In conclusion, CXCL16 contributed to the development of HNSCC cells by modulating the GPX1-mediated antioxidant pathway. Thus, targeting cellular CXCL16 expression seems to be a promising strategy for treating HNSCC.

Role of chemokine receptors in gastrointestinal mucosa

Chemokine receptors are essential for the immune response in the oral and gut mucosa. The gastrointestinal mucosa is characterized by the presence of immune populations because it is susceptible to inflammatory and infectious diseases, necessitating immune surveillance. Chemokine receptors are expressed on immune cells and play a role in gastrointestinal tissue-homing, although other non-immune cells also express them for various biological functions. CCR9, CXCR3 and CXCR6 play an important role in the T cell response in inflammatory and neoplastic conditions of the gastrointestinal mucosa. However, CXCR6 could also be found in gastric cancer cells, highlighting the different roles of chemokine receptors in different pathologies. On the other hand, CCR4 and CCR8 are critical for Treg migration in gastrointestinal tissues, correlating with poor prognosis in mucosal cancers. Other chemokine receptors are also important in promoting myeloid infiltration with context-dependent roles. Further, CXCR4 and CXCR7 are also present in gastrointestinal tumor cells and are known to stimulate proliferation, migration, and invasion into other tissues, among other pro-tumorigenic functions. Determining the processes underlying mucosal immunity and creating tailored therapeutic approaches for gastrointestinal diseases requires an understanding of the complex interactions that occur between chemokine receptors and their ligands in these mucosal tissues.

Involvement of CXC chemokines (CXCL1-CXCL17) in gastric cancer: Prognosis and therapeutic molecules

Gastric cancer (GC) is the fifth-most prevalent and second-most deadly cancer worldwide. Due to the late onset of symptoms, GC is frequently treated at a mature stage. In order to improve the diagnostic and clinical decision-making processes, it is necessary to establish more specific and sensitive indicators valuable in the early detection of the disease whenever a cancer is asymptomatic. In this work, we gathered information about CXC chemokines and GC by using scientific search engines including Google Scholar, PubMed, SciFinder, and Web of Science. Researchers believe that GC chemokines, small proteins, class CXC chemokines, and chemokine receptors promote GC inflammation, initiation, and progression by facilitating angiogenesis, tumor transformation, invasion, survival, metastatic spread, host response safeguards, and inter-cell interaction. With our absolute best professionalism, the role of CXC chemokines and their respective receptors in GC diagnosis and prognosis has not been fully explained. This review article updates the general characteristics of CXC chemokines, their unique receptors, their function in the pathological process of GC, and their potential application as possible indicators for GC. Although there have only recently been a few studies focusing on the therapeutic efficacy of CXC chemokine inhibitors in GC, growing experimental evidence points to the inhibition of CXC chemokines as a promising targeted therapy. Therefore, further translational studies are warranted to determine whether specific antagonists or antibodies designed to target CXC chemokines alone or in combination with chemotherapy are useful for diagnosing advanced GC.

Chemokines: Function and therapeutic potential in bone metastasis of lung cancer

Lung cancer is a rapidly progressing disease with a poor prognosis. Bone metastasis is commonly found in 40.6% of advanced-stage patients. The mortality rate of lung cancer patients with bone metastasis can be significantly decreased by implementing novel diagnostic techniques, improved staging and classification systems, precise surgical interventions, and advanced treatment modalities. However, it is important to note that there is currently a lack of radical procedures available for these patients due to the development of drug resistance. Consequently, palliative care approaches are commonly employed in clinical practice. Therefore, new understandings of the process of bone metastasis of lung cancer are critical for developing better treatment strategies to improve patient's clinical cure rate and quality of life. Chemokines are cell-secreted small signaling proteins in cancer occurrence, proliferation, invasion, and metastasis. In this study, we review the development of bone metastasis in lung cancer and discuss the mechanisms of specific chemokine families (CC, CXC, CX3C, and XC) in regulating the biological activities of tumors and promoting bone metastasis. We also highlight some preclinical studies and clinical trials on chemokines for lung cancer and bone metastasis.

The role of CXCL family members in different diseases

Chemokines are a large family mediating a lot of biological behaviors including chemotaxis, tumor growth, angiogenesis and so on. As one member of this family, CXC subfamily possesses the same ability. CXC chemokines can recruit and migrate different categories of immune cells, regulate tumor's pathological behaviors like proliferation, invasion and metastasis, activate angiogenesis, etc. Due to these characteristics, CXCL subfamily is extensively and closely associated with tumors and inflammatory diseases. As studies are becoming more and more intensive, CXCLs' concrete roles are better described, and CXCLs' therapeutic applications including biomarkers and targets are also deeply explained. In this review, the role of CXCL family members in various diseases is summarized.

Tumor-associated macrophages promote cisplatin resistance in ovarian cancer cells by enhancing WTAP-mediated N6-methyladenosine RNA methylation via the CXCL16/CXCR6 axis

PURPOSE

Tumor-promotive tumor-associated macrophages (TAMs) and the CXCL16/CXCR6 axis have been reported to be correlated with the limited efficacy of chemotherapy in ovarian cancer (OC). However, the role of TAM-secreted CXCL16 and the mechanism by which it affects the cisplatin (DDP) resistance of OC cells remain elusive.

METHODS

We induced human THP-1 monocytes to differentiate into macrophages. Next, SKOV3 and TOV-112D cells were co-cultured with the macrophages, followed by incubation with increasing concentrations of DDP. The effects of CXCL16, CXCR6, and WTAP on the DDP resistance of OC cells were investigated using the CCK-8 assay, colony formation assay, flow cytometry, and TUNEL staining. CXCL16 concentrations were determined by ELISA. Quantitative real-time PCR and western blotting were used to examine related markers.

RESULTS

Our results showed that after being co-cultured with TAMs, the DDP resistance of OC cells was significantly enhanced and their CXCL16 levels were elevated. Acquired DDP resistance was characterized by an increased IC50 value for DDP, the formation of cell colonies, and decreased levels of cell apoptosis, which were accompanied by reduced levels of caspase-3 and Bax expression, and increased levels of Bcl-2, PARP1, BRCA1, and BRCA2 expression. Either CXCL16 knockdown in TAMs or CXCR6 knockdown in OC cells suppressed the DDP resistance of OC cells that had been co-cultured with TAMs. Knockdown of CXCL16 affected m6A RNA methylation in OC cells, as reflected by decreased YTHDF1/WTAP expression and increased ALKBH5 expression. WTAP overexpression and knockdown promoted and suppressed the DDP resistance of OC cells, respectively.

CONCLUSION

Tumor-associated macrophages promote the cisplatin resistance of OC cells by enhancing WTAP-mediated N6-methyladenosine RNA methylation via the CXCL16/CXCR6 axis.

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.

Integrated analysis of Helicobacter pylori-related prognostic gene modification patterns in the tumour microenvironment of gastric cancer

BACKGROUND

Helicobacter pylori (HP) infection is one of the leading causes of gastric cancer (GC). However, the interaction between HP and the TME, and its carcinogenic mechanism remains unknown.

METHODS

The HP-related prognostic genes were identified based on HP infection-related gene markers and HP infection sample datasets by risk method and NMF algorithm. Principal component analysis (PCA) algorithm was used to constructed the HPscore system. The "limma" R package was employed to determine differentially expressed genes. In addition, the R packages, such as "xCell" and "GSVA", was used to analyze the relationship between the HPscore and tumor microenvironment. Finally, quantitative real-time polymerase chain reaction (qRT-PCR) was conducted to verify the expression levels of 28 HP-related prognostic genes in tissues.

RESULTS

We successfully identified 28 HP-related prognostic genes that accurately classified the GC population. There are significant differences in survival between different subgroups (high-, low-risk and cluster_1,2). Thereafter, the HPscore system was constructed to evaluate the signatures of the 28 HP-related prognostic genes. The overall survival rate in the high-HPscore group was poor and immunological surveillance was reduced, whereas the low-HPscore group had a survival advantage and was related to the inflammatory response. HPscore was also strongly correlated with the tumour stage, TME cell infiltration and stemness. The qRT-PCR results showed that DOCK4 expression level of 28 HP-related prognostic genes was higher in gastric cancer tissues than in adjacent tissues.

CONCLUSIONS

HP signatures play a crucial role in the TME and tumourigenesis. HPscore evaluation of a single tumour sample can help identify the TME characteristics and the carcinogenic mechanism of GC patients infected with HP, based on which personalized treatment can be administered.

Exploration of the Tumor Immune Landscape and Identification of Two Novel Immunotherapy-Related Genes for Epstein-Barr virus-associated Gastric Carcinoma via Integrated Bioinformatics Analysis

Epstein–Barr virus (EBV)-associated gastric carcinoma (EBVaGC) is a specific molecular subtype of gastric carcinoma with a high proportion of tumor-infiltrating lymphocytes. It is a highly immunogenic tumor that may benefit from immunotherapy. Hence, it is imperative to analyze the immune landscape and identify immunotherapy biomarkers for EBVaGC. In our study, we investigated the immune landscape and identified 10 hub genes for EBVaGC via integrated bioinformatics analysis. We found that EBVaGC expressed more immune-related genes, including common immune checkpoints and human leukocyte antigen (HLA) genes than EBV-negative gastric carcinoma (EBVnGC). The immune score in EBVaGC was higher, which means EBVaGC has greater immune cell infiltration. Ten hub genes (CD4, STAT1, FCGR3A, IL10, C1QA, CXCL9, CXCL10, CXCR6, PD-L1, and CCL18) were detected as candidate biomarkers for EBVaGC. Two hub genes, CXCL9 and CXCR6, were identified as novel immunotherapy-related genes. Taken together, the results of our comprehensive analysis of the immune microenvironment of EBVaGC revealed its unique immune landscape, demonstrating that it is a highly immunogenic tumor. Moreover, we identified hub genes that may serve as potential immunotherapy biomarkers for EBVaGC.

C-C Motif Chemokine Ligand-17 as a Novel Biomarker and Regulator of Epithelial Mesenchymal Transition in Renal Fibrogenesis

CCL17, a chemotactic cytokine produced by macrophages, is known to promote inflammatory and fibrotic effects in multiple organs, but its role in mediating renal fibrosis is unclear. In our study cohort of 234 chronic kidney disease (CKD) patients and 65 healthy controls, human cytokine array analysis revealed elevated CCL17 expression in CKD that correlated negatively with renal function. The area under the receiver operating characteristic curve of CCL17 to predict the development of CKD stages 3b–5 was 0.644 (p < 0.001), with the optimal cut-off value of 415.3 ng/mL. In vitro over-expression of CCL17 in HK2 cells had no effect on cell viability, but increased cell motility and the expression of α-SMA, vimentin and collagen I, as shown by western blot analysis. In a unilateral ureteral obstruction (UUO) mouse model, we observed significantly increased interstitial fibrosis and renal tubule dilatation by Masson’s Trichrome and H&E staining, and markedly increased expression of CCL17, vimentin, collagen I, and α-SMA by IHC stain, qRTPCR, and western blotting. CCL17 induced renal fibrosis by promoting the epithelial-mesenchymal transition, resulting in ECM accumulation. CCL17 may be a useful biomarker for predicting the development of advanced CKD.