CCR9 as a prognostic marker and therapeutic target in hepatocellular carcinoma

Exploration of prognostic and treatment markers in hepatocellular carcinoma via GPCR-related genes analysis

Background

G protein-coupled receptors (GPCRs), the biggest family of signaling receptors, account for 34 % of all the drug targets approved by the Food and Drug Administration (FDA). It has been gradually recognized that GPCRs are of significance for tumorigenesis, but in-depth studies are still required to explore specific mechanisms. In this study, the role of GPCRs in hepatocellular carcinoma (HCC) was elucidated, and GPCR-related genes were employed for building a risk-score model for the prognosis and treatment efficacy prediction of HCC patients.

Methods

Patients' data on HCC were sourced from the Liver Hepatocellular Carcinoma-Japan (LIRI-JP) and The Cancer Genome Atlas (TCGA) databases, while GPCR-related genes were obtained from the Molecular Signatures Database (MSigDB). Univariant and multivariant Cox regression analyses, as well as least absolute shrinkage and selection operator (LASSO) were performed with the aim of identifying differentially expressed GPCR-related genes and grouping patients. Differential expression and functional enrichment analyses were performed; protein-protein interaction (PPI) mechanisms were explored; hub genes and micro ribonucleic acid (miRNA)-target gene regulatory networks were constructed. The tumor immune dysfunction and exclusion (TIDE) algorithm was utilized to evaluate immune infiltration levels and genetic variations. Sensitivity to immunotherapy and common antitumor drugs was predicted via the database Genomics of Drug Sensitivity in Cancer (GDSC).

Results

A GPCR-related risk score containing eight GPCR-related genes (atypical chemokine receptor 3 (ACKR3), C-C chemokine receptor type 3 (CCR3), CCR7, frizzled homolog 5 (FZD5), metabotropic glutamate receptor 8 (GRM8), hydroxycarboxylic acid receptor 1 (HCAR1), 5-hydroxytryptamine receptor 5A (HTR5A) and nucleotide-binding oligomerization domain-like receptor family pyrin domain containing 6 (NLRP6)) was set up. In addition, patients were classified into groups with high and low risks. Patients in the high-risk group exhibited a worse prognosis but demonstrated a more favorable immunotherapy response rate compared with those in the low-risk group. Distinct sensitivity to chemotherapeutic drugs was observed. A clinical prediction model on the basis of GPCR-related risk scores was constructed. Areas under the curves (AUC) corresponding to one-, three- and five-year survival were 0.731, 0.765 and 0.731, respectively.

Conclusions

In this study, an efficient HCC prognostic prediction model was constructed by only GPCR-related genes, which are all potential targets for HCC treatment.

Activated fibroblasts induce immune escape of TSCC through CCL25/AKT pathway

OBJECTIVES

Accumulating evidence suggests that activated fibroblasts are the key cells in the T-cell response to tumor immunosuppression. We attempted to investigate the effect of activated fibroblasts on PD-L1 expression and the related immune escape mechanism in tongue squamous cell carcinoma.

METHODS

Western blotting, qPCR, and other techniques were used to study the expression of PD-L1 in tongue squamous cell carcinoma cells and the nude mouse model of transplanted tumors in vivo; clinical tissue samples were verified. In addition, we established a direct coculture model of T cells and tongue squamous cell carcinoma cells explore the mechanisms of immune escape.

RESULTS

We found that PDGF-BB induces fibroblast activation by facilitating the oversecretion of chemokine CCL25. Further analysis showed that CCL25 derived from activated fibroblasts activated the Akt signaling pathway to promote PD-L1 expression. The activated fibroblasts inhibited T-cell IFN-γ secretion through the CCL25/Akt/PD-L1 pathway, which indirectly inhibited T-cell proliferation.

CONCLUSION

Activated fibroblasts can induce the high expression of PD-L1 in the oral and tongue squamous cell carcinoma cell line Cal-27 via the CCL25/CCR9/p-Akt axis, to significantly inhibit the proliferation and IFN-γ secretion of T cells and promote the immune escape of tongue squamous cell carcinoma cells.

Establishment of a Sensitive Monoclonal Antibody Against Mouse CCR9 (C9Mab-24) for Flow Cytometry

The CC chemokine receptor 9 (CCR9), also known as CD199, is one of chemokine receptors. The CC chemokine ligand 25 (CCL25) is known to be the only ligand for CCR9. The CCR9-CCL25 interaction plays important roles in chemotaxis of lymphocytes and tumor cell migration. Therefore, CCR9-CCL25 axis is a promising target for tumor therapy and diagnosis. In this study, we established a sensitive and specific monoclonal antibody (mAb) against mouse CCR9 (mCCR9) using N-terminal peptide immunization method. The established anti-mCCR9 mAb, C₉Mab-24 (rat immunoglobulin [IgG]_2a, kappa), reacted with mCCR9-overexpressed Chinese hamster ovary-K1 (CHO/mCCR9) and mCCR9-endogenously expressed cell line, RL2, through flow cytometry. Kinetic analyses using flow cytometry showed that the dissociation constants (K_D) of C₉Mab-24 for CHO/mCCR9 and RL2 cell lines were 6.0 × 10^-9 M and 4.7 × 10^-10 M, respectively. Results indicated that C₉Mab-24 is useful for detecting mCCR9 through flow cytometry, thereby providing a possibility for targeting mCCR9-expressing cells in vivo experiments.

C9Mab-1: An Anti-Mouse CCR9 Monoclonal Antibody for Immunocytochemistry

C-C motif chemokine receptor 9 (CCR9) is a G protein-coupled receptor, which is highly expressed in T-lymphocytes and different cancer cells. CCR9 aggravates immune diseases and cancer progression and is considered a biomarker and a therapeutic target of diseases. The development of specific monoclonal antibody (mAbs) for human CCR9 (hCCR9) is required to diagnose and treat immune diseases and cancers. Previously, we established the cell-based immunization and screening (CBIS) method, which does not need purified target proteins. Anti-hCCR9 mAb (clone C₉Mab-1; mouse IgG₁, kappa) was also developed using the CBIS method. C₉Mab-1 is usable for flow cytometry against exogenously and endogenously expressing hCCR9. This study showed that C₉Mab-1 and its recombinant antibody (recC₉Mab-1) specifically detected exogenous hCCR9 stably overexpressed in Chinese hamster ovary (CHO)-K1 cells and endogenous hCCR9 expressed in a human T-lymphoblastic leukemia cell line MOLT-4 cells through immunocytochemistry. This study provides a new application of C₉Mab-1 and recC₉Mab-1 in immunocytochemistry.

Development of Anti-Human CC Chemokine Receptor 9 Monoclonal Antibodies for Flow Cytometry

CC chemokine receptor 9 (CCR9) belongs to the beta chemokine receptor family and is mainly distributed on the surface of immature T lymphocytes and enterocytes. This receptor is highly expressed in rheumatoid arthritis, colitis, type 2 diabetes, and various tumors. Therefore, more sensitive monoclonal antibodies (mAbs) need to be developed to predict the prognosis of many high CCR9 expression diseases. Because CCR9 is a structurally unstable G protein-coupled receptor, it has been difficult to develop anti-CCR9 mAbs using the traditional method. This study developed anti-human CCR9 (hCCR9) mAbs for flow cytometry using a Cell-Based Immunization and Screening (CBIS) method. Two mice were immunized with hCCR9-overexpressed Chinese hamster ovary (CHO)-K1 cells (CHO/hCCR9), and hybridomas showing strong signals from CHO/hCCR9 and no signals from CHO-K1 cells were selected by flow cytometry. We established an anti-hCCR9 mAb, C₉Mab-1 (IgG₁, kappa), which detected hCCR9 in MOLT-4 leukemia T lymphoblast cells and CHO/hCCR9 cells by flow cytometry. Our study showed that an anti-hCCR9 mAb was developed more rapidly by the CBIS method than the previous method.

Role of CC chemokine receptor 9 in the progression of murine and human non-alcoholic steatohepatitis

BACKGROUND & AIMS

The number of patients with non-alcoholic steatohepatitis (NASH) is increasing globally. Recently, specific chemokine receptors have garnered interest as therapeutic targets in NASH. This is the first report to examine the role of the C-C chemokine receptor 9 (CCR9)/C-C chemokine receptor ligand 25 (CCL25) axis, and to reveal its therapeutic potential in NASH.

METHODS

Patients with biopsy-proven non-alcoholic liver disease (NAFLD) were recruited and their serum and hepatic chemokine expression was examined. Furthermore, wild-type (WT) and Ccr9^-/- mice were fed a high-fat high-cholesterol (HFHC) diet for 24 weeks to establish NASH.

RESULTS

Serum CCL25, and hepatic CCR9 and CCL25 expression levels were increased in patients with NASH compared to healthy volunteers. Furthermore, Ccr9^-/- mice were protected from HFHC diet-induced NASH progression both serologically and histologically. Flow cytometry and immunohistochemistry analysis showed that CCR9⁺CD11b⁺ inflammatory macrophages accumulated in the inflamed livers of HFHC diet-fed mice, while the number was reduced in Ccr9^-/- mice. Consistent with human NASH livers, CCR9 was also expressed on hepatic stellate cells (HSCs) in mice with NASH, while CCR9-deficient HSCs showed less fibrogenic potential in vitro. Administration of a CCR9 antagonist hampered further fibrosis progression in mice with NASH, supporting its potential clinical application. Finally, we showed that CCR9 blockade attenuated the development of NAFLD-related hepatocellular carcinoma in HF diet-fed mice injected with diethylnitrosamine.

CONCLUSIONS

These results highlight the role of the CCR9/CCL25 axis on macrophage recruitment and fibrosis formation in a murine NASH model, providing new insights into therapeutic strategies for NASH.

LAY SUMMARY

Herein, we show that a specific chemokine axis involving a receptor (CCR9) and its ligand (CCL25) contributes to the progression of non-alcoholic steatohepatitis and carcinogenesis in humans and mice. Furthermore, treatment with a CCR9 antagonist ameliorates the development of steatohepatitis and holds promise for the treatment of patients with non-alcoholic steatohepatitis.

CCR9 and CCL25: A review of their roles in tumor promotion

Chemokines constitute a superfamily of small chemotactic cytokines with functions that are based on interactions with their corresponding receptors. It has been found that, among other functions, chemokines regulate the migratory and invasive abilities of cancer cells. Multiple studies have confirmed that chemokine receptor 9 (CCR9) and its exclusive ligand, chemokine 25 (CCL25), are overexpressed in a variety of malignant tumors and are closely associated with tumor proliferation, apoptosis, invasion, migration and drug resistance. This review evaluates recent advances in understanding the role of CCR9/CCL25 in cancer development. First, we outline the general background of chemokines in cancer and the structure and function of CCR9 and CCL25. Next, we describe the basic function of CCR9/CCL25 in the cancer process. Then, we introduce the role of CCR9/CCL25 and related signaling pathways in various cancers. Finally, future research directions are proposed. In general, this paper is intended to serve as a comprehensive repository of information on this topic and is expected to contribute to the design of other research projects and future efforts to develop treatment strategies for ameliorating the effects of CCR9/CCL25 in cancer.

Cell Surface Proteins in Hepatocellular Carcinoma: From Bench to Bedside

Cell surface proteins act as the go-between in carrying the information from the extracellular environment to the intracellular signaling proteins. However, these proteins are often deregulated in neoplastic diseases, including hepatocellular carcinoma. This review discusses several recent studies that have investigated the role of cell surface proteins in the occurrence and progression of HCC, highlighting the possibility to use them as biomarkers of the disease and/or targets for vaccines and therapeutics.

Bufalin inhibits cell proliferation and migration of hepatocellular carcinoma cells via APOBEC3F induced intestinal immune network for IgA production signaling pathway

OBJECTIVE

This study aimed to evaluate functions of APOBEC3F gene in biological process of hepatocellular carcinoma (HCC) and anti-tumor mechanisms of bufalin.

METHODS

Effect of APOBEC3F and bufalin on cell proliferation and migration abilities were evaluated by CCK-8, wounding healing tests and transwell assays in SK-Hep1 and Bel-7404 cells. Bioinformatic analysis were also used to compare APOBEC3F expression levels, detect coexpressed genes and enrichment of pathways.

RESULTS

APOBEC3F was overexpressed in tumor tissues compared to adjacent tissues in HCC patients. And, APOBEC3F promotes cell proliferation and migration in SK-Hep1 and Bel-7404 cells. Bufalin inhibits cell proliferation and migration and reduces APOBEC3F expression. GO and KEGG enrichment of APOBEC3F-coexpressed genes revealed that APOBEC3F might active intestinal immune network for IgA production signaling pathway, leading to malignant biological behaviors of HCC cells. Additionally, siAPOBEC3F could decrease pIgR, CCR9, CCR10 and CXCR4 protein levels. And, bufalin inhibits the pIgR, CCR9, CCR10 and CXCR4 protein expressions.

CONCLUSIONS

Bufalin inhibits cell proliferation and migration of HCC cells via APOBEC3F induced intestinal immune network for IgA production signaling pathway.

The role of chemokine receptor 9/chemokine ligand 25 signaling: From immune cells to cancer cells

Chemokine ligand 25 (CCL25) and chemokine receptor 9 (CCR9) are important regulators of migration, proliferation and apoptosis in leukocytes and cancer cells. Blocking of the CCR9/CCL25 signal has been demonstrated to be a potential novel cancer therapy. Research into CCR9 and CCL25 has revealed their associated upstream and downstream signaling pathways; CCR9 is regulated by several immunological factors, including NOTCH, interleukin 2, interleukin 4 and retinoic acid. NOTCH in particular, has been revealed to be a crucial upstream regulator of CCR9. Furthermore, proteins including matrix metalloproteinases, P-glycoprotein, Ezrin/Radixin/Moesin and Livin are regulated via phosphatidylinositol-3 kinase/protein kinase B, which are in turn stimulated by CCR9/CCL25. This is a review of the current literature on the functions and signaling pathways of CCR9/CCL25.

Emerging Roles of G Protein-Coupled Receptors in Hepatocellular Carcinoma

Among a great variety of cell surface receptors, the largest superfamily is G protein-coupled receptors (GPCRs), also known as seven-transmembrane domain receptors. GPCRs can modulate diverse signal-transduction pathways through G protein-dependent or independent pathways which involve β-arrestins, G protein receptor kinases (GRKs), ion channels, or Src kinases under physiological and pathological conditions. Recent studies have revealed the crucial role of GPCRs in the tumorigenesis and the development of cancer metastasis. We will sum up the functions of GPCRs—particularly those coupled to chemokines, prostaglandin, lysophosphatidic acid, endothelin, catecholamine, and angiotensin—in the proliferation, invasion, metastasis, and angiogenesis of hepatoma cells and the development of hepatocellular carcinoma (HCC) in this review. We also highlight the potential avenues of GPCR-based therapeutics for HCC.

Gd-EOB-DTPA-enhanced magnetic resonance imaging combined with T1 mapping predicts the degree of differentiation in hepatocellular carcinoma

BACKGROUND

Variable degrees of differentiation in hepatocellular carcinoma(HCC)under Edmondson-Steiner grading system has been proven to be an independent prognostic indicator for HCC. Up till now, there has been no effective radiological method that can reveal the degree of differentiation in HCC before surgery. This paper aims to evaluate the use of Gd-EOB-DTPA-Enhanced Magnetic Resonance Imaging combined with T1 mapping for the diagnosis of HCC and assessing its degree of differentiation.

METHODS

Forty-four patients with 53 pathologically proven HCC had undergone Gd-EOB-DTPA enhanced MRI with T1 mapping before surgery. Out of the 53 lesions,13 were grade I, 27 were gradeII, and 13 were grade III. The T1 values of each lesion were measured before and at 20 min after Gd-EOB-DTPA administration (T1p and T1e). The absolute reduction in T1 value (T1d) and the percentage reduction (T1d %) were calculated. The one-way ANOVA and Pearson correlation were used for comparisons between the T1 mapping values.

RESULTS

The T1d and T1d % of grade I, II and III of HCC was 660.5 ± 422.8ms、295.0 ± 99.6ms、276.2 ± 95.0ms and 54.0 ± 12.2 %、31.5 ± 6.9 %、27.7 ± 6.7 % respectively. The differences between grade Iand II, grade Iand III were statistically significant (p < 0.05), but there was no statically significant difference between grade II and III. The T1d % was the best marker for grading of HCC, with a Spearman correlation coefficient of -0.676.

CONCLUSIONS

T1 mapping before and after Gd-EOB-DTPA administration can predict degree of differentiation in HCC.

C-C Motif Chemokine Receptor 9 Exacerbates Pressure Overload-Induced Cardiac Hypertrophy and Dysfunction

Background

Maladaptive cardiac hypertrophy is a major risk factor for heart failure, which is the leading cause of death worldwide. C‐C motif chemokine receptor 9 (CCR9), a subfamily of the G protein–coupled receptor supergene family, has been highlighted as an immunologic regulator in the development and homing of immune cells and in immune‐related diseases. Recently, CCR9 was found to be involved in the pathogenesis of other diseases such as cardiovascular diseases; however, the effects that CCR9 exerts in cardiac hypertrophy remain elusive.

Methods and Results

We observed significantly increased CCR9 protein levels in failing human hearts and in a mouse or cardiomyocyte hypertrophy model. In loss‐ and gain‐of‐function experiments, we found that pressure overload–induced hypertrophy was greatly attenuated by CCR9 deficiency in cardiac‐specific CCR9 knockout mice, whereas CCR9 overexpression in cardiac‐specific transgenic mice strikingly enhanced cardiac hypertrophy. The prohypertrophic effects of CCR9 were also tested in vitro, and a similar phenomenon was observed. Consequently, we identified a causal role for CCR9 in pathological cardiac hypertrophy. Mechanistically, we revealed a lack of difference in the expression levels of mitogen‐activated protein kinases between groups, whereas the phosphorylation of AKT/protein kinase B and downstream effectors significantly decreased in CCR9 knockout mice and increased in CCR9 transgenic mice after aortic binding surgery.

Conclusions

The prohypertrophic effects of CCR9 were not attributable to the mitogen‐activated protein kinase signaling pathway but rather to the AKT–mammalian target of rapamycin–glycogen synthase kinase 3β signaling cascade.

CCR9 in cancer: oncogenic role and therapeutic targeting

Cancer is currently one of the leading causes of death worldwide and is one of the most challenging major public health problems. The main challenges faced by clinicians in the management and treatment of cancer mainly arise from difficulties in early diagnosis and the emergence of tumor chemoresistance and metastasis. The structures of chemokine receptor 9 (CCR9) and its specific ligand chemokine ligand 25 (CCL25) have been elucidated, and, interestingly, a number of studies have demonstrated that CCR9 is a potential tumor biomarker in diagnosis and therapy, as it has been found to be highly expressed in a wide range of cancers. This expression pattern suggests that CCR9 may participate in many important biological activities involved in cancer progression. Researchers have shown that CCR9 that has been activated by its specific ligand CCL25 can interact with many signaling pathways, especially those involved in tumor chemoresistance and metastasis. This review, therefore, focuses on CCR9 induction activity and summarizes what is currently known regarding its role in cancers and its potential application in tumor-targeted therapy.

Expression of CC chemokine receptor 9 predicts poor prognosis in patients with lung adenocarcinoma

Background

The CC chemokine receptor 9 (CCR9) plays an important role in tumorigenesis and metastasis in various cancers. Our previous studies have shown the aberrant expression of CCR9 in non-small cell lung cancer (NSCLC) cell lines, revealing that the CCR9-CCL25 axis modulates cell migration and invasion, and supports cancer cell survival by inhibiting apoptosis in vitro and in vivo. In the present study, we aimed to evaluate the expression and possible prognostic role of CCR9 in lung adenocarcinoma.

Methods

Immunohistochemical analysis of CCR9 expression was performed on 144 lung adenocarcinoma tissues and 30 adjacent normal lung parenchymal tissues. We assessed the correlation of CCR9 expression with clinicopathological characteristics and the prognosis of lung adenocarcinoma.

Results

The expression of CCR9 was increased in lung adenocarcinoma tissue compared with normal lung tissue. Moreover, such an expression was positively correlated with tumor size (p = 0.032), lymph node metastasis (p = 0.002) and advanced TNM stage (p = 0.012). In addition, the patients with negative CCR9 expression exhibited a higher overall survival (OS) compared with those with positive CCR9 expression. Multivariate analysis showed that the CCR9 expression was an independent prognostic factor for the OS of patients with lung adenocarcinoma.

Conclusions

We, for the first time, reported that CCR9 could be beneficial in predicting lymph node metastasis, and it might act as a novel prognostic biomarker for lung adenocarcinoma.

Chemokines and their receptors play important roles in the development of hepatocellular carcinoma

The chemokine system consists of four different subclasses with over 50 chemokines and 19 receptors. Their functions in the immune system have been well elucidated and research during the last decades unveils their new roles in hepatocellular carcinoma (HCC). The chemokines and their receptors in the microenvironment influence the development of HCC by several aspects including: inflammation, effects on immune cells, angiogenesis, and direct effects on HCC cells. Regarding these aspects, pre-clinical research by targeting the chemokine system has yielded promising data, and these findings bring us new clues in the chemokine-based therapies for HCC.

CCR9-CCL25 interaction suppresses apoptosis of lung cancer cells by activating the PI3K/Akt pathway

CC chemokine receptor-9 (CCR9) is highly expressed in non-small cell lung cancer (NSCLC) tissues and cell lines. However, the biological functions and the signals elicited by the interaction between CCR9 and its natural ligand CCL25 in NSCLC are unknown. Here, we selectively depleted CCR9 and inhibited CCR9-CCL25 interaction in NSCLC cells using small recombinant lentivirus-mediated miRNA, and investigated the tumorigenic effects in vitro and in vivo. Compromised CCR9-CCL25 interaction promoted apoptosis in NSCLC cells by activating phosphoinositide 3-kinase (PI3K)/Akt in vitro. In addition, we showed that CCR9-CCL25 interaction mediated the activation of the PI3K/Akt pathway in NSCLC cells, resulting in the up-regulation of anti-apoptotic proteins, as well as the down-regulation of apoptotic proteins in a PI3K-/Akt-dependent manner. These CCR9-CCL25-mediated effects were abrogated in the presence of a PI3K inhibitor (wortmannin 10 nM) or by inhibiting the CCR9-CCL25 interaction through CCR9 silencing, which also suggested that the biological function of CCR9-CCL25 was mainly regulated by PI3K. In vivo studies also demonstrated a significantly lower tumor burden in mice receiving CCR9-silence cells than those in mice receiving control cells. Together, these data suggested that CCR9-CCL25 interaction induced tumorigenesis of NSCLC cells and that this induction might be accomplished through the activation of the PI3K/Akt pathway. These findings may lead to a better understanding of the biological effects of CCR9-CCL25 interaction and provide clues for identifying novel therapeutic and preventive molecular markers for NSCLC.