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

Genetic variants of LRRC8C, OAS2, and CCL25 in the T cell exhaustion-related genes are associated with non-small cell lung cancer survival

Background

T cell exhaustion is a state in which T cells become dysfunctional and is associated with a decreased efficacy of immune checkpoint inhibitors. Lung cancer has the highest mortality among all cancers. However, the roles of genetic variants of the T cell exhaustion-related genes in the prognosis of non-small cell lung cancer (NSCLC) patients has not been reported.

Methods

We conducted a two-stage multivariable Cox proportional hazards regression analysis with two previous genome-wide association study (GWAS) datasets to explore associations between genetic variants in the T cell exhaustion-related genes and survival of NSCLC patients. We also performed expression quantitative trait loci analysis for functional validation of the identified variants.

Results

Of all the 52,103 single nucleotide polymorphisms (SNPs) in 672 T cell exhaustion-related genes, 1,721 SNPs were found to be associated with overall survival (OS) of 1185 NSCLC patients of the discovery GWAS dataset from the Prostate, Lung, Colorectal and Ovarian (PLCO) Cancer Screening Trial, and 125 of these 1,721 SNPs remained significant after validation in an additional independent replication GWAS dataset of 984 patients from the Harvard Lung Cancer Susceptibility (HLCS) Study. In multivariable stepwise Cox model analysis, three independent SNPs (i.e., LRRC8C rs10493829 T>C, OAS2 rs2239193 A>G, and CCL25 rs3136651 T>A) remained significantly associated with OS with hazards ratios (HRs) of 0.86 (95% confidence interval (CI) = 0.77-0.96, P = 0.008), 1.48 (95% CI = 1.18-1.85, P < 0.0001) and 0.78 (95% CI = 0.66-0.91, P = 0.002), respectively. Further combined analysis for these three SNPs suggested that an unfavorable genotype score was associated with a poor OS and disease-specific survival. Expression quantitative trait loci analysis suggested that the LRRC8C rs10493829 C allele was associated with elevated LRRC8C mRNA expression levels in normal lymphoblastoid cells, lung tissue, and whole blood.

Conclusion

Our findings suggested that these functional SNPs in the T cell exhaustion-related genes may be prognostic predictors for survival of NSCLC patients, possibly via a mechanism of modulating corresponding gene expression.

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.

Determination of the Binding Epitope of an Anti-Mouse CCR9 Monoclonal Antibody (C9Mab-24) Using the 1× Alanine and 2× Alanine-Substitution Method

C-C chemokine receptor 9 (CCR9) is a receptor for C-C-chemokine ligand 25 (CCL25). CCR9 is crucial in the chemotaxis of immune cells and inflammatory responses. Moreover, CCR9 is highly expressed in tumors, including several solid tumors and T-cell acute lymphoblastic leukemia. Several preclinical studies have shown that anti-CCR9 monoclonal antibodies (mAbs) exert antitumor activity. Therefore, CCR9 is an attractive target for tumor therapy. In this study, we conducted the epitope mapping of an anti-mouse CCR9 (mCCR9) mAb, C₉Mab-24 (rat IgG_2a, kappa), using the 1× alanine (1× Ala)- and 2× alanine (2× Ala)-substitution methods via enzyme-linked immunosorbent assay. We first performed the 1× Ala-substitution method using one alanine-substituted peptides of the mCCR9 N-terminus (amino acids 1-19). C₉Mab-24 did not recognize two peptides (F14A and F17A), indicating that Phe14 and Phe17 are critical for C₉Mab-24-binding to mCCR9. Furthermore, we conducted the 2× Ala-substitution method using two consecutive alanine-substituted peptides of the mCCR9 N-terminus, and showed that C₉Mab-24 did not react with four peptides (M13A-F14A, F14A-D15A, D16A-F17A, and F17A-S18A), indicating that _13-MFDDFS_-18 is involved in C₉Mab-24-binding to mCCR9. Overall, combining, the 1× Ala- or 2× Ala-scanning methods could be useful for understanding for target-antibody interaction.

Characteristics and Resistance to Cisplatin of Human Neuroblastoma Cells Co-Cultivated with Immune and Stromal Cells

We investigated the features of the morphology and cytokine profiles of neuroblastoma SH-SY5Y cells, bone marrow-derived mesenchymal stromal/stem cells (BM-MSCs), and peripheral blood mononuclear cells (PBMCs) in double (BM-MSCs + SH-SY5Y cells) and triple (BM-MSCs + SH-SY5Y cells + PBMCs) co-cultures incubated on plastic and Matrigel. Cells in the co-cultures communicated by vesicular transport and by exchanging membrane and cytoplasmic components. The cytokine profile of double and triple co-cultures incubated on Matrigel and plastic had differences and showed the highest concentration of a number of chemokines/cytokines, such as CXCL8/IL-8, I-TAC/CXCL11, IP10/CXCL10, MDC/CCL22, MIP-1α/CCL3, IL-1β, ENA-78/CXCL5, Gro-α/CXCL1, MCP-1/CCL2, TERC/CCL25, CXCL8/IL-8, and IL-6. High concentrations of inflammatory chemokines/cytokines in the conditioned medium of triple co-culture form a chronic inflammation, which brings the presented co-cultivation system closer to a natural tumor. Triple co-cultures were more resistant to cisplatin (CDDP) than the double- and monoculture of SH-SY5Y. The mRNA levels of BCL2, BCL2L1, RAC1, CAV1, CASP3, and BAX genes were changed in cells after co-culturing and CDDP treatment in double and triple co-cultures. The expression of the BCL2, BAX, CAV1, and CASP3 proteins in SH-SY5Y cells after the triple co-culture and CAV1 and BAX protein expression in SH-SY5Y cells after the double co-culture were determined. This study demonstrated the nature of the cellular interactions between components of tumor niche and the intercellular influence on chemoresistance observed in our tumor model, which should enable the development of novel test systems for anti-tumor agents.

CCL25/CCR9 interaction promotes the malignant behavior of salivary adenoid cystic carcinoma via the PI3K/AKT signaling pathway

Background

CC chemokine receptor 9 (CCR9), an organ-specific chemokine receptor, interacts with its exclusive ligand CCL25 to promote tumor proliferation and metastasis. However, the effect of CCR9 on salivary adenoid cystic carcinoma (SACC) malignant behavior remains unknown. This study aimed to investigate the specific molecular mechanism by which CCR9/CCL25 modulates malignant progression in SACC.

Methods

Immunohistochemistry staining and RT-qPCR analyses were performed to detect the correlation of CCR9 expression and tumor progression-associated markers in SACC. In vitro, SACC cell proliferation and apoptosis were evaluated using Cell Counting Kit-8 and colon formation, and cell migration and invasion were detected by wound healing and transwell assays. Vercirnon was used as an inhibitor of CCR9, and LY294002 was used as an inhibitor of the PI3K/AKT pathway in this study. Western blot and RT-qPCR assays were carried out to measure the downstream factors of the interaction of CCL25 and CCR9. The effect of CCL25 on the development of SACC in vivo was examined by a xenograft tumor model in nude mice following CCL25, Vercirnon and LY294002 treatment.

Results

CCR9 was highly expressed in SACC compared with adjacent salivary gland tissues, and its level was associated with tumor proliferation and metastases. CCL25 enhanced cell proliferation, migration, and invasion through its interaction with CCR9 and exerted an antiapoptotic effect on SACC cells. Targeting CCR9 via Vercirnon significantly reduced the phosphorylation level of AKT induced by CCL25. CCL25/CCR9 could activate its downstream factors through the PI3K/AKT signaling pathway, such as cyclin D1, BCL2 and SLUG, thus promoting SACC cell proliferation, antiapoptosis, invasion and metastasis. The in vivo data from the xenograft mouse models further proved that CCL25 administration promoted malignant tumor progression by activating the PI3K/AKT pathway.

Conclusion

The interaction of CCL25 and CCR9 promotes tumor growth and metastasis in SACC by activating the PI3K/AKT signaling pathway, offering a promising strategy for SACC treatment.

Therapeutic potential of an anti-CCR9 mAb evidenced in xenografts of human CCR9+ tumors

Relapsed or refractory T acute lymphoblastic leukemia (T-ALL) still carries poor prognosis. Aiming to improve outcomes, the therapeutic potential of an anti-CCR9 monoclonal antibody (mAb 92R), targeting the human chemokine-receptor CCR9 is analyzed on orthotopic xenotransplants. 92R mAb treatment of mice carrying human CCR9⁺ T-ALL cell lines or primary T cell leukemias inhibits tumor growth and increases survival. The therapeutic effects of 92R are specific and synergize with chemotherapeutic agents increasing survival. Furthermore, 92R decreases size of non-hematopoietic tumors with a forced CCR9 expression and of solid tumors generated by the pancreatic adenocarcinoma cell line AsPC-1. In addition, a humanized version of 92R mAb (Srb1) is also able to inhibit growth of CCR9⁺ T-ALL tumor cells in vivo, increasing survival 2.66-fold. Finally, 92R mAb prevents liver accumulation of infiltrates and reduces tumor cell numbers in already formed infiltrates. Thus, the humanized version of 92R mAb (Srb1), displays therapeutic potential for CCR9⁺ tumor treatment and might represent one of the first therapeutic antibodies for precision medicine on T-ALL patients.

Chemokines and NSCLC: Emerging role in prognosis, heterogeneity, and therapeutics

Lung cancer persists to contribute to one-quarter of cancer-associated deaths. Among the different histologies, non-small cell lung cancer (NSCLC) alone accounts for 85% of the cases. The development of therapies involving immune checkpoint inhibitors and angiogenesis inhibitors has increased patients' survival probability and reduced mortality rates. Developing targeted therapies against essential genetic alterations also translates to better treatment strategies. But the benefits still seem farfetched due to the development of drug resistance and refractory tumors. In this review, we have highlighted the interplay of different tumor microenvironment components, essentially discussing the chemokine families (CC, CXC, C, and CX3C) that regulate the tumor biology in NSCLC and promote tumor growth, metastasis, and associated heterogeneity. The development of therapeutics and prognostic markers is a complex and multipronged approach. However, some essential chemokines can act as critical players for being considered potential prognostic markers and therapeutic targets.

Advances in Research on the Effects and Mechanisms of Chemokines and Their Receptors in Cancer

Cancer is a common and intractable disease that seriously affects quality of life of patients and imposes heavy economic burden on families and the entire society. Current medications and intervention strategies for cancer have respective shortcomings. In recent years, it has been increasingly spotlighted that chemokines and their receptors play vital roles in the pathophysiology of cancer. Chemokines are a class of structurally similar short-chain secreted proteins that initiate intracellular signaling pathways through the activation of corresponding G protein-coupled receptors and participate in physiological and pathological processes such as cell migration and proliferation. Studies have shown that chemokines and their receptors have close relationships with cancer epigenetic regulation, growth, progression, invasion, metastasis, and angiogenesis. Chemokines and their receptors may also serve as potential targets for cancer treatment. We herein summarize recent research progresses on anti-tumor effects and mechanisms of chemokines and their receptors, suggesting avenues for future studies. Perspectives for upcoming explorations, such as development of multi-targeted chemokine-based anti-tumor drugs, are also discussed in the present review.

TIPE polarity proteins are required for mucosal deployment of T lymphocytes and mucosal defense against bacterial infection

Mucosal surfaces are continuously exposed to, and challenged by, numerous commensal and pathogenic organisms. To guard against infections, a majority of the thymus-derived T lymphocytes are deployed at the mucosa. Although chemokines are known to be involved in the mucosal lymphocyte deployment, it is not clear whether lymphocytes enter the mucosa through directed migration or enhanced random migration. Here we report that TIPE (tumor necrosis factor-α-induced protein 8 (TNFAIP8)-like) proteins mediate directed migration of T lymphocytes into lung mucosa, and they are crucial for mucosal immune defense against Streptococcus pneumoniae infection. Knockout of both Tnfaip8 and Tipe2, which encode polarity proteins that control the directionality of lymphocyte migration, significantly reduced the numbers of T lymphocytes in the lung of mice. Compared with wild-type mice, Tnfaip8^−/−Tipe2^−/− mice also developed more severe infection with more pathogens entering blood circulation upon nasal Streptococcus pneumoniae challenge. Single-cell RNA-sequencing analysis revealed that TIPE proteins selectively affected mucosal homing of a unique subpopulation of T cells, called “T cells-2”, which expressed high levels of Ccr9, Tcf7, and Rag1/2 genes. TNFAIP8 and TIPE2 appeared to have overlapping functions since deficiency in both yielded the strongest phenotype. These data demonstrate that TIPE family of proteins are crucial for lung mucosal immunity. Strategies targeting TIPE proteins may help develop mucosal vaccines or treat inflammatory diseases of the lung.

LINC00853 restrains T cell acute lymphoblastic leukemia invasion and infiltration by regulating CCR9/CCL25

BACKGROUND

Leukemia is a group of hematopoietic malignancies characterized by the accumulation and infiltration of abnormal hematopoietic stem cells or early progenitor cells. T cell acute lymphoblastic leukemia (T-ALL) is a hematologic malignancy occurring in 15 % of pediatric and 25 % of adult ALL cases. Infiltration and metastasis of leukemic cells to specific organs are consequences of disease relapse and dismal prognosis. Long non-coding RNAs (lncRNAs) have been identified to function in the migration, invasion and infiltration of tumors by regulating gene expression. Our previous studies showed that CC chemokine receptor 9 (CCR9), which specifically bind to CC chemokine ligand 25 (CCL25), promotes T-ALL infiltration.

METHODS

Bioinformatic methods were used to screen LINC00853 in gene expression omnibus (GEO) datasets. RT-qPCR, western bolt and flow cytometry were applied to detect the expression of LINC00853 and CCR9. Transwell and martrigel-transwell were employed to assess the cells migration and invasion abilities. Fluorescence microscope was applied to observed the green fluorescence protein positive (GFP⁺) cells. Lentivirus and adenovirus were packed to construct nc-blank, sh-LINC00853-blank and sh-LINC00853-rescue jurkat cell lines.

RESULTS

In this study, we found out the negative correlation of LINC00853 and CCR9 expression. LINC00853 was downregulated while CCR9 was upregulated in GEO datasets, T-ALL cell lines and clinical samples. Moreover, LINC00853 suppressed jurkat cells migration and invasion in vitro and restrained infiltration in liver, spleen, kidney, lung, brain, ovary of nonobese diabetic/severe combined immunodeficient (NOD/SCID) mice.

CONCLUSIONS

These findings indicate that LINC00853 restrains T-ALL cell invasion and infiltration by regulating CCR9/CCL25.

An Immune-Related Gene Prognostic Index for Triple-Negative Breast Cancer Integrates Multiple Aspects of Tumor-Immune Microenvironment

Simple Summary

Triple-negative breast cancer (TNBC) is the most refractory subtype of breast cancer. Immune checkpoint inhibitor (ICI) therapy has made progress in TNBC treatment. PD-L1 expression is a useful biomarker of ICI therapy efficacy. However, tumor-immune microenvironment (TIME) factors, such as immune cell compositions and tumor-infiltrating lymphocyte (TIL) status, also influence tumor immunity. Therefore, it is necessary to seek biomarkers that are associated with multiple aspects of TIME in TNBC. In this study, we developed an immune-related gene prognostic index (IRGPI) with a substantial prognostic value for TNBC. Moreover, the results from multiple cohorts reproducibly demonstrate that IRGPI is significantly associated with immune cell compositions, the exclusion and dysfunction of TILs, as well as PD-1 and PD-L1 expression in TIME. Therefore, IRGPI is a promising biomarker closely related to patient survival and TIME of TNBC and may have a potential effect on the immunotherapy strategy of TNBC.

Abstract

Tumor-immune cell compositions and immune checkpoints comprehensively affect TNBC outcomes. With the significantly improved survival rate of TNBC patients treated with ICI therapies, a biomarker integrating multiple aspects of TIME may have prognostic value for improving the efficacy of ICI therapy. Immune-related hub genes were identified with weighted gene co-expression network analysis and differential gene expression assay using The Cancer Genome Atlas TNBC data set (n = 115). IRGPI was constructed with Cox regression analysis. Immune cell compositions and TIL status were analyzed with CIBERSORT and TIDE. The discovery was validated with the Molecular Taxonomy of Breast Cancer International Consortium data set (n = 196) and a patient cohort from our hospital. Tumor expression or serum concentrations of CCL5, CCL25, or PD-L1 were determined with immunohistochemistry or ELISA. The constructed IRGPI was composed of CCL5 and CCL25 genes and was negatively associated with the patient’s survival. IRGPI also predicts the compositions of M0 and M2 macrophages, memory B cells, CD8⁺ T cells, activated memory CD4 T cells, and the exclusion and dysfunction of TILs, as well as PD-1 and PD-L1 expression of TNBC. IRGPI is a promising biomarker for predicting the prognosis and multiple immune characteristics of TNBC.

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.

[Synergistic effect of polysaccharide from Trichoderma pseudokoningii and oxaliplatin on colorectal cancer cells in vitro]

OBJECTIVE

To explore the synergistic inhibitory effect of polysaccharide from Trichoderma pseudokoningii (EPS) and oxaliplatin (Oxa) on colorectal cancer (CRC) HCT116 cells.

OBJECTIVE

HCT116 cells were treated with 8 μg/mL Oxa and 100 μg/mL EPS alone or in combination, and the changes in cell viability was assessed with CCK-8 assay. CompuSyn software was used for fitting the Fa-CI curve to evaluate the combined effect of the two agents. Flow cytometry was performed to analyze cell apoptosis and cell cycle changes, and wound healing assay and Transwell assay were used to examine the migration ability of the treated cells. Oxa- and EPS-related genes and CRC-related genes were intersected for protein-protein interaction (PPI) analysis and GO and KEGG enrichment analyses.

OBJECTIVE

Treatment with Oxa alone or in combination with EPS significantly inhibited the viability of HCT116 cells in a dose- and time-dependent manner, and the two agents exhibited a significant synergistic effect (CI < 1). The combined treatment with Oxa and EPS resulted in a significantly higher total cell apoptosis rate and a higher percentage of cells in S phase than Oxa alone and the control treatment (P < 0.05). EPS and Oxa alone both inhibited the migration of HCT116 cells, and their combination produced a stronger inhibitory effect. GO enrichment analysis of the key genes related with Oxa, EPS and CRC suggested that these genes were involved mainly in such biological processes as exogenous apoptosis signaling, cell response to chemical stress, and reactive oxygen metabolism; KEGG analysis showed that these genes were involved in the pathways of drug resistance, apoptosis and angiogenesis.

OBJECTIVE

EPS and Oxa can synergistically inhibit the proliferation of HCT116 cells possibly through the PI3K-Akt, MAPK, VEGF, and p53 signaling pathways.

A novel immune-related prognostic signature in epithelial ovarian carcinoma

The immune response is associated with the progression and prognosis of epithelial ovarian cancer (EOC). However, the roles of infiltrated immune cells and immune-related genes (IRGs) in EOC have not been reported comprehensively. In the current study, the differentially expressed genes (DEGs) were filtered based on the integrated gene expression data acquired from The University of California at Santa Cruz (UCSC) Genome Browser. Then, IRGs and transcriptional factors (TFs) were screened based on the ImmPort database and Cistrome database. A total of 501 differentially expressed IRGs, and 76 TFs were detected. A TF-mediated network was constructed by univariate Cox analysis to reveal the potential regulatory mechanisms of IRGs. Next, a nine immune-based prognostic risk model using nine IRGs (PI3, CXCL10, CXCL11, LCN6, CCL17, CCL25, MIF, CX3CR1, and CSPG5) was established. Based on the risk score worked out from the signature, the EOC patients could be classified into low-risk and high-risk groups. Furthermore, the immune landscapes, elevated by the cell-type identification by estimating relative subsets of RNA transcripts (CIBERSORT) algorithm and the Tumor Immune Estimation Resource (TIMER) database, effectuated different patterns in two groups. Thus, an immune-based prognostic risk model of EOC elucidates the immune status in the tumor microenvironment, and hence, could be used for prognosis.

CCL25 and CCR9 is a unique pathway that potentiates pannus formation by remodeling RA macrophages into mature osteoclasts

This study elucidates the mechanism of CCL25 and CCR9 in rheumatoid arthritis (RA). RA synovial fluid (SF) expresses elevated levels of CCL25 compared to OA SF and plasma from RA and normal. CCL25 was released into RA SF by fibroblasts (FLS) and macrophages (MΦs) stimulated with IL-1β and IL-6. CCR9 is also presented on IL-1β and IL-6 activated RA FLS and differentiated MΦs. Conversely, in RA PBMCs neither CCL25 nor CCR9 are impacted by 3-month longitudinal TNF inhibitor therapy. CCL25 amplifies RA FLS and monocyte infiltration via p38 and ERK phosphorylation. CCL25-stimulated RA FLS secrete potentiated levels of IL-8 which is disrupted by p38 and ERK inhibitors. CCL25 polarizes RA monocytes into nontraditional M1 MΦs that produce IL-8 and CCL2. Activation of p38 and ERK cascades are also responsible for the CCL25-induced M1 MΦ development. Unexpectedly, CCL25 was unable to polarize RA PBMCs into effector Th1/Th17 cells. Consistently, lymphokine like RANKL was uninvolved in CCL25-induced osteoclastogenesis; however, this manifestation was regulated by osteoclastic factors such as RANK, cathepsin K (CTSK), and TNF-α. In short, we reveal that CCL25/CCR9 manipulates RA FLS and MΦ migration and inflammatory phenotype in addition to osteoclast formation via p38 and ERK activation.

CCL25 Signaling in the Tumor Microenvironment

Multiple checkpoint mechanisms are overridden by cancer cells in order to develop into a tumor. Neoplastic cells, while constantly changing during the course of cancer progression, also craft their surroundings to meet their growing needs. This crafting involves changing cell surface receptors, affecting response to extracellular signals and secretion of signals that affect the nearby cells and extracellular matrix architecture. This chapter briefly comprehends the non-cancer cells facilitating the cancer growth and elaborates on the notable role of the CCR9-CCL25 chemokine axis in shaping the tumor microenvironment (TME), directly and via immune cells. Association of increased CCR9 and CCL25 levels in various tumors has demonstrated the significance of this axis as a tool commonly used by cancer to flourish. It is involved in attracting immune cells in the tumor and determining their fate via various direct and indirect mechanisms and, leaning the TME toward immunosuppressive state. Besides, elevated CCR9-CCL25 signaling allows survival and rapid proliferation of cancer cells in an otherwise repressive environment. It modulates the intra- and extracellular protein matrix to instigate tumor dissemination and creates a supportive metastatic niche at the secondary sites. Lastly, this chapter abridges the latest research efforts and challenges in using the CCR9-CCL25 axis as a cancer-specific target.

The role of the CCL25-CCR9 axis in beta-cell function: potential for therapeutic intervention in type 2 diabetes

BACKGROUND AND PURPOSE

Chemokines are known to play essential roles mediating immunity and inflammation in many physiological and pathophysiological processes, with reports linking their action to the development of obesity, insulin resistance and type 2 diabetes (T2D). Given our findings of highly upregulated mRNA expression of the chemokine receptor CCR9 in islets from obese human donors, we have determined the effects of CCR9 activation by CCL25 on islet function and viability.

BASIC PROCEDURES

RT-qPCR was used to measure expression of 384 GPCR mRNAs in human islets from organ donors with normal and elevated BMI. mRNA encoding CCR9, a receptor that was highly upregulated in islets from obese donors, was also quantified in islets from lean and high-fat diet (HFD) mice. The effects of CCR9 activation by exogenous CCL25 in human and mouse islets and its inhibition by the CCR9 antagonist vercirnon on insulin secretion, apoptosis and cAMP accumulation were examined using standard techniques.

MAIN FINDINGS

The qPCR analysis showed altered expression of several GPCRs in islets isolated from lean and obese donors. CCR9 displayed over 90-fold upregulation in islets from obese individuals, and it was also significantly upregulated in islets from obese mice. In isolated human and mouse islets exogenous CCL25 inhibited glucose-induced insulin secretion in a concentration-dependent manner, enhanced cytokine-induced apoptosis and significantly reduced forskolin-induced elevation in cAMP levels. These detrimental effects of CCL25 in islets were blocked by vercirnon, which had no effect on its own.

PRINCIPAL CONCLUSIONS

We have shown that CCL25 acts via the Gαi-coupled receptor CCR9 to impair beta-cell function by inhibiting insulin secretion and promoting cytokine-induced apoptosis. Upregulation of CCR9 in islets in obesity, possibly secondary to accumulation of passenger immune cells, may predispose to metabolic dysfunction and our data suggest that CCL25 downregulation or CCR9 inhibition could be explored to treat T2D.

CC Chemokines in a Tumor: A Review of Pro-Cancer and Anti-Cancer Properties of Receptors CCR5, CCR6, CCR7, CCR8, CCR9, and CCR10 Ligands

CC chemokines (or β-chemokines) are 28 chemotactic cytokines with an N-terminal CC domain that play an important role in immune system cells, such as CD4⁺ and CD8⁺ lymphocytes, dendritic cells, eosinophils, macrophages, monocytes, and NK cells, as well in neoplasia. In this review, we discuss human CC motif chemokine ligands: CCL1, CCL3, CCL4, CCL5, CCL18, CCL19, CCL20, CCL21, CCL25, CCL27, and CCL28 (CC motif chemokine receptor CCR5, CCR6, CCR7, CCR8, CCR9, and CCR10 ligands). We present their functioning in human physiology and in neoplasia, including their role in the proliferation, apoptosis resistance, drug resistance, migration, and invasion of cancer cells. We discuss the significance of chemokine receptors in organ-specific metastasis, as well as the influence of each chemokine on the recruitment of various cells to the tumor niche, such as cancer-associated fibroblasts (CAF), Kupffer cells, myeloid-derived suppressor cells (MDSC), osteoclasts, tumor-associated macrophages (TAM), tumor-infiltrating lymphocytes (TIL), and regulatory T cells (T_reg). Finally, we show how the effect of the chemokines on vascular endothelial cells and lymphatic endothelial cells leads to angiogenesis and lymphangiogenesis.

Toll Like Receptor 4 Mediated Lymphocyte Imbalance Induces Nec-Induced Lung Injury

Necrotizing enterocolitis (NEC) is the leading cause of death from gastrointestinal disease in premature infants, and is associated with the development of severe lung inflammation. The pathogenesis of NEC-induced lung injury remains unknown, yet infiltrating immune cells may play a role. In support of this possibility, we now show that NEC in mice and humans was associated with the development of profound lung injury that was characterized by an influx of Th17 cells and a reduction in T regulatory lymphocytes (Tregs). Importantly, the adoptive transfer of CD4 T cells isolated from lungs of mice with NEC into the lungs of immune incompetent mice (Rag1 mice) induced profound inflammation in the lung, while the depletion of Tregs exacerbated NEC induced lung injury, demonstrating that imbalance of Th17/Treg in the lung is required for the induction of injury. In seeking to define the mechanisms involved, the selective deletion of toll-like receptor 4 (TLR4) from the Sftpc1 pulmonary epithelial cells reversed lung injury, while TLR4 activation induced the Th17 recruiting chemokine (C-C motif) ligand 25 (CCL25) in the lungs of mice with NEC. Strikingly, the aerosolized inhibition of both CCL25 and TLR4 and the administration of all trans retinoic acid restored Tregs attenuated NEC-induced lung injury. In summary, we show that TLR4 activation in Surfactant protein C-1 (Sftpc1) cells disrupts the Treg/Th17 balance in the lung via CCL25 leading to lung injury after NEC and reveal that inhibition of TLR4 and stabilization of Th17/Treg balance in the neonatal lung may prevent this devastating complication of NEC.

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.

CCL25 promotes the migration and invasion of non-small cell lung cancer cells by regulating VEGF and MMPs in a CCR9-dependent manner

The CC chemokine receptor 9 (CCR9) and its natural secreted ligand CC motif chemokine ligand 25 (CCL25) have been implicated in cancer metastasis. However, their metastatic potential in non-small cell lung cancer (NSCLC) remains unclear. In the present study, immunohistochemistry was used to detect the expression and localization of CCR9, vascular endothelial growth factor (VEGF), matrix metalloproteinase (MMP)-1 and MMP-7 in lung cancer tissue and adjacent normal tissue. The association between the expression of CCR9 and clinical variables was also examined. Reverse transcription-quantitative PCR and western blotting were conducted to detect the expression of VEGF-C, VEGF-D, MMP-1 and MMP-7 in lung cancer cell lines (A549 and SK-MES-1). Migration and invasion assays were conducted to examine cell migration and invasion. Survival and mutation analysis were conducted using published datasets. The expressions of CCR9, VEGF, MMP-1 and MMP-7 were upregulated in cancer tissue, compared with adjacent normal tissue (all P<0.05). Patients with lower expression of CCR9 or CCL25 had better overall survival (OS) compared with those with higher CCR9 or CCL25 expression (P<0.05 and P=0.05, respectively). Furthermore, the expressions of VEGF-C, VEGF-D, MMP-1 and MMP-7 were higher in the CCL25-treated cell lines (all P<0.05), but MMP-7 protein expression was not affected by CCL25 treatment in SK-MES-1 cells (P>0.05). Following treatment with CCL25, lung cancer cells demonstrated higher migratory and invasive potential, which could be blocked by the CCR9 antibody (P<0.05). Survival analysis demonstrated that low expression levels of both CCR9 and CCL25 mRNA indicated favorable OS in patients with NSCLC. Altogether, these results suggested that CCL25 enhanced the phenotype associated with migration and invasion in NSCLC by regulating the expression of VEGF-C, VEGF-D, MMP-1 and MMP-7.

The CC and CXC chemokines: major regulators of tumor progression and the tumor microenvironment

Chemokines are a family of soluble cytokines that act as chemoattractants to guide the migration of cells, in particular of immune cells. However, chemokines are also involved in cell proliferation, differentiation, and survival. Chemokines are associated with a variety of human diseases including chronic inflammation, immune dysfunction, cancer, and metastasis. This review discusses the expression of CC and CXC chemokines in the tumor microenvironment and their supportive and inhibitory roles in tumor progression, angiogenesis, metastasis, and tumor immunity. We also specially focus on the diverse roles of CXC chemokines (CXCL9-11, CXCL4 and its variant CXCL4L1) and their two chemokine receptor CXCR3 isoforms, CXCR3-A and CXCR3-B. These two distinct isoforms have divergent roles in tumors, either promoting (CXCR3-A) or inhibiting (CXCR3-B) tumor progression. Their effects are mediated not only directly in tumor cells but also indirectly via the regulation of angiogenesis and tumor immunity. A full comprehension of their mechanisms of action is critical to further validate these chemokines and their receptors as biomarkers or therapeutic targets in cancer.

Chemotherapy and Inflammatory Cytokine Signalling in Cancer Cells and the Tumour Microenvironment

Cancer is the result of a cell's acquisition of a variety of biological capabilities or 'hallmarks' as outlined by Hanahan and Weinberg. These include sustained proliferative signalling, the ability to evade growth suppressors, resisting cell death, enabling replicative immortality, inducing angiogenesis, and the ability to invade other tissue and metastasize. More recently, the ability to escape immune destruction has been recognized as another important hallmark of tumours. It is suggested that genome instability and inflammation accelerates the acquisition of a variety of the above hallmarks. Inflammation, is a product of the body's response to tissue damage or pathogen invasion. It is required for tissue repair and host defense, but prolonged inflammation can often be the cause for disease. In a cancer patient, it is often unclear whether inflammation plays a protective or deleterious role in disease progression. Chemotherapy drugs can suppress tumour growth but also induce pathways in tumour cells that have been shown experimentally to support tumour progression or, in other cases, encourage an anti-tumour immune response. Thus, with the goal of better understanding the context under which each of these possible outcomes occurs, recent progress exploring chemotherapy-induced inflammatory cytokine production and the effects of cytokines on drug efficacy in the tumour microenvironment will be reviewed. The implications of chemotherapy on host and tumour cytokine pathways and their effect on the treatment of cancer patients will also be discussed.

AAV-Vectored Fms-Related Tyrosine Kinase 3 Ligand Inhibits CD34+ Progenitor Cell Engraftment in Humanized Mice

Humanized mice have become useful animal models for HIV/AIDS. Since NOD.Cg-Prkdc scid Il2rgtm1Wjl/SzJ (NSG) mice allow the engraftment of primary human immune cells, we aim to determine the role of human Fms-related tyrosine kinase 3 ligand (hFlt3L), a major growth factor for dendritic cells (DCs), in regulating the differentiation of cord blood-derived CD34⁺ progenitor cells in this murine species. Soluble recombinant hFlt3L protein and AAV-vectored hFlt3L were administrated before or after human CD34⁺ progenitor cell transplantation, respectively. We then measured the peripheral levels of hFlt3L by ELISA. Meantime, reconstituted human immune cells were analyzed by flow cytometry over time. We found that without hFlt3L there were significantly increased types of human immune cells in NSG-huCD34 compared with NSG-huPBL mice but the frequency of human DCs remains low. Transient treatment with recombinant hFlt3L expanded human conventional CD1c⁺ and CD141⁺ DCs as well as plasmacytoid DCs in humanized NSG-huCD34 mice. Surprisingly, however, the prolonged in vivo expression of AAV-vectored hFlt3L resulted in significant suppression of total human CD34⁺ cell engraftment and differentiation. The suppression occurred within 2 weeks when AAV-vectored hFlt3L was administered either before or after the transplantation of CD34⁺ progenitor cells, which was likely associated with the induction of murine myeloid-derived immune suppressive cells and reactive oxygen species in NSG-huCD34 mice. Since chronic  HIV-1 patients displayed significantly high levels of hFlt3L expression, our findings may have implication to explore the role of prolonged hFlt3L in regulating  the differentiation of human CD34⁺ progenitor cells in both NSG-huCD34 mice and infected people. Graphical Abstract ᅟ.

Evidence for the Involvement of COX-2/VEGF and PTEN/Pl3K/AKT Pathway the Mechanism of Oroxin B Treated Liver Cancer

Background

Oroxin B (OB) is one of flavonoids isolated from traditional Chinese herbal medicine Oroxylum indicum (L.) Vent. Recent studies suggest that flavonoids have obvious anti-liver tumors effect, but the precise molecular mechanism is still unclear.

Objective

The current study was performed to investigate the antitumor effects of OB on human hepatoma cell line SMMC-772 and explore the part of molecular mechanisms in this process.

Materials and Methods

MTT method, terminal deoxynucleotidyl transferase dUTP nick end labeling assay and flow cytometry were utilized to detect the inhibition of proliferation and the apoptosis after treating OB in of SMMC-7721 cells. The mRNA and proteins expressions of COX-2, vascular endothelial growth factor (VEGF), phosphatidylinositol-3-kinase (PI3K), p-AKT, and PTEN were measured by a real-time polymerase chain reaction and Western Blot method.

Results

The results showed that OB inhibited proliferation of SMMC-7721 cell in a dose-dependent manner, and induced its apoptosis. Moreover, OB unregulated PTEN and downregulated COX-2, VEGF, p-AKT, and PI3K.

Conclusion

Our results demonstrated that OB significantly inhibits proliferation and induce apoptosis, which may be strongly associated with the inhibiting COX-2/VEGF and PTEN/PI3K/AKT pathway signaling pathway in SMMC-7721 cells, OB potentially be used as a novel therapeutic agent for liver cancer.

SUMMARY

OB (Oroxin B) is one of the effective flavonoid components of traditional Chinese medicine O. indicum (L.)OB can inhibite the proliferation and promoted apoptosis of the human hepatoma cell line SMMC 7721OB plays a role of antitumor effect may to regulate COX 2/VEGF and PTEN/PI3K/AKT pathways directly or indirectly. Abbreviations used: OB: Oroxin B; MTT: 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide; COX-2: cyclooxygenase-2; PI3K: phosphatidylinositol 3 kinase; PTEN: Phosphatase and tensin homolog deleted on chromosome ten; VEGF: Vascular endothelial growth factor; RT-PCR: Reverse transcription polymerase chain reaction; DAPI: Diamidino 2 phenylindole; PBS: Phosphate buffer saline; FITC: Fluorescein isothiocyanate; PI: Propidium Iodide; RIPA: Radio immunoprecipitation assay lysis buffer; PMSF: Phenylmethanesulfonyl fluoride; PAGE: Polyacrylamide gel electrophoresis.

Total Flavonoids from Oroxylum indicum Induce Apoptosis via PI3K/Akt/PTEN Signaling Pathway in Liver Cancer

Total flavonoids (TF), derived from the seeds of Oroxylum indicum (L.) Vent., possess many pharmacological functions. In the present study, H22-bearing mice and SMMC-7721 models were employed to evaluate the antitumor activity of TF and to and investigate its possible mechanisms both in vitro and in vivo. Cell viability was evaluated by MTT assay; cell apoptosis rate was analyzed via Annexin V-FITC/PI double staining by flow cytometer. Meanwhile, the expressions of apoptosis-related mRNA and proteins were evaluated by RT-PCR and Western blot analysis. The results revealed that TF could significantly inhibit the tumor growth, and the possible mechanism was related to the effect of inducing tumor cells apoptosis through PI3K/Akt/PTEN signaling pathway. This study has provided a theoretical basis for the further development and application of TF as antitumor drugs.

92R Monoclonal Antibody Inhibits Human CCR9+ Leukemia Cells Growth in NSG Mice Xenografts

CCR9 is as an interesting target for the treatment of human CCR9⁺-T cell acute lymphoblastic leukemia, since its expression is limited to immature cells in the thymus, infiltrating leukocytes in the small intestine and a small fraction of mature circulating T lymphocytes. 92R, a new mouse mAb (IgG2a isotype), was raised using the A-isoform of hCCR9 as immunogen. Its initial characterization demonstrates that binds with high affinity to the CCR9 N-terminal domain, competing with the previously described 91R mAb for receptor binding. 92R inhibits human CCR9⁺ tumor growth in T and B-cell deficient Rag2^−/− mice. In vitro assays suggested complement-dependent cytotoxicity and antibody-dependent cell-mediated cytotoxicity as possible in vivo mechanisms of action. Unexpectedly, 92R strongly inhibited tumor growth also in a model with compromised NK and complement activities, suggesting that other mechanisms, including phagocytosis or apoptosis, might also be playing a role on 92R-mediated tumor elimination. Taken together, these data contribute to strengthen the hypothesis of the immune system’s opportunistic nature.

Novel peptide screened from a phage display library antagonizes the activity of CC chemokine receptor 9

CC chemokine receptor 9 (CCR9) serves a role in the drug resistance and metastasis of tumors. In the present study, a peptide specifically bound to CCR9 was obtained and the effect on tumor cells was observed. A Ph.D.-12 phage display peptide library was used to screen for peptides binding specifically to the second extracellular loop of CCR9. The ratios of the input and output of phage clones increased gradually following three rounds of biopanning. A total of 8 positive phage clones were identified from DNA analysis. A phage clone, C-4, was identified which exhibited higher affinity and specificity for the second extracellular loop of CCR9 in vitro compared with other clones. A peptide (P1; VHWDFRQWWQPS) was identified which may inhibit the corresponding phage, C-4, binding to the second extracellular loop of CCR9. Furthermore, P1 was able to bind specifically with MOLT4 cells which exhibit marked expression of CCR9. In addition, P1 promoted the apoptosis of MOLT4 cells induced by doxorubicin, and inhibited the migration of MOLT4 cells in the presence of chemokine (C-C motif) ligand 25. It was suggested that decreased activity in the phosphorylation of protein kinase B in MOLT4 cells may be responsible for the inhibition. In conclusion, the peptide P1 derived from a screened phage is able to specifically bind to CCR9 and inhibit the activity of CCR9. It has potential use as an antagonist in the treatment of CCR9-overexpressed carcinoma.

Loss of PFKFB4 induces cell death in mitotically arrested ovarian cancer cells

Taxanes represent some of the most commonly used chemotherapeutic agents for ovarian cancer treatment. However, they are only effective in approximately 40% of patients. Novel therapeutic strategies are required to potentiate their effect and improve patient outcome. A hallmark of many cancers is the constitutive activation of the PI3K/AKT pathway, which drives cell survival and metabolism. We discovered a striking decrease in AKT activity coupled with a significant reduction in glucose 6-phosphate and ATP levels during mitotic arrest in the majority of ovarian cancer cell lines tested, indicating a potential metabolic vulnerability. A high-content siRNA screen to detect novel metabolic targets in mitotically arrested ovarian cancer cells identified the glycolytic enzyme PFKFB4. PFKFB4 depletion increased caspase 3/7 activity, and levels of reactive oxygen species only in mitotically arrested cells, and significantly enhanced mitotic cell death after paclitaxel treatment. Depletion of PFKFB3 demonstrated a similar phenotype. The observation that some ovarian cancer cells lose AKT activity during mitotic arrest and become vulnerable to metabolic targeting is a new concept in cancer therapy. Thus, combining mitotic-targeted therapies with glycolytic inhibitors may act to potentiate the effects of antimitotics in ovarian cancer through mitosis-specific cell death.

Genome-wide DNA methylation analysis in renal ischemia reperfusion injury

Renal ischemia reperfusion injury (IRI) is frequently encountered after kidney transplantation and is a leading cause of acute renal failure. Aberrant gene expression and epigenetic regulation occur during the pathophysiology of IRI. In this study, we used reduced representation bisulfite sequencing to identify the DNA methylome of renal tissues during IRI and the sham-operated tissues in C57BL/6. The methylation status of approximately 1.29 million CpGs located in an average of 11554 CpG islands and 17113 promoters in genome was determined. Compared with sham-operated kidney, both acute and chronic IRI significantly decreased the genome-wide methylation level (1.1-1.8%) and the CpG methylation level in the promoter (0.4-0.5%), CpG island (0.5-1.3%), exon (1.3-1.9%), and intron (0.8-1.1%; all P<10^-153). The promoters of 200, 191, and 79 genes were differentially methylated in the renal tissues at 24h, 7days, and at both the time points after IRI, respectively. Among the 79 genes, which were consistently epigenetically regulated at two time points, 18 genes (22.8%) showed differential expression after IRI in a previous study of renal expression. We validated the promoter methylation status and expression of five out of the 18 genes, including 2700049A03Rik, Ccr9, Fgd2, Pfkfb3, and Sdc4 in an independent renal tissue cohort. We found that all the five genes exhibited altered methylation of promoter (P=0.009-0.0001) following renal injury. The promoter methylation of 2700049A03Rik and Ccr9 was negatively correlated with their mRNA expression in renal tissues (P<0.001 and P<0.0001, respectively). Our study not only demonstrated a genome-wide DNA methylation pattern in the IR-injured renal tissue for the first time, but also indicated that the regulation of promoter methylation is an important mechanism underlying persistent alteration of gene expression.

CCR9 Is a Key Regulator of Early Phases of Allergic Airway Inflammation

Airway inflammation is the most common hallmark of allergic asthma. Chemokine receptors involved in leukocyte recruitment are closely related to the pathology in asthma. CCR9 has been described as a homeostatic and inflammatory chemokine receptor, but its role and that of its ligand CCL25 during lung inflammation remain unknown. To investigate the role of CCR9 as a modulator of airway inflammation, we established an OVA-induced allergic inflammation model in CCR9-deficient mice. Here, we report the expression of CCR9 and CCL25 as early as 6 hours post-OVA challenge in eosinophils and T-lymphocytes. Moreover, in challenged CCR9-deficient mice, cell recruitment was impaired at peribronchial and perivenular levels. OVA-administration in CCR9-deficient mice leads to a less inflammatory cell recruitment, which modifies the expression of IL-10, CCL11, and CCL25 at 24 hours after OVA challenge. In contrast, the secretion of IL-4 and IL-5 was not affected in CCR9-deficient mice compared to WT mice. These results demonstrate for the first time that CCR9 and CCL25 expressions are induced in the early stages of airway inflammation and they have an important role modulating eosinophils and lymphocytes recruitment at the first stages of inflammatory process, suggesting that they might be a potential target to regulate inflammation in asthma.

Incomplete radiofrequency ablation accelerates proliferation and angiogenesis of residual lung carcinomas via HSP70/HIF-1α

Radiofrequency ablation (RFA) therapy has been proved effective and feasible for lung cancer. However, the molecular mechanisms of local lung cancer recurrence following RFA are poorly understood. The present study aimed to evaluate the ability of HSP70/HIF-1α to affect the proliferation and angiogenesis of non-small cell lung cancers (NSCLCs) following insufficient RFA to uncover the molecular mechanisms of local recurrence. In vitro heat treatment was used to establish sublines of NCI-H1650 cells. The NCI-H1650 subline that was established by heat treatment at 54°C had a relatively higher viability and significantly elevated heat tolerance (compared to the parental strain). After treatment with the HSP70 inhibitor VER-155008, the HIF-1α inhibitor YC-1 and PI3K/Akt inhibitor wortmannin, the viability and proliferation rate of the cells was measured. At the same time, HSP70, HIF-1α and Akt were detected by real-time PCR and western blotting. In vivo xenograft tumors were created by subcutaneously inoculating nude mice with NCI-H1650 cells. HSP70, HIF-1α and Akt were detected by western blotting, and CD34 expression was detected by immunohistochemistry before and after RFA or treatment with the VER-155008, YC-1 or wortmannin inhibitors. The heat-adapted NCI-H1650 subline established in vitro had a higher viability and proliferative activity compared to parental cells. Inhibiting HSP70/HIF-1α abolished this difference. Blocking the PI3K/Akt signaling pathway decreased HSP70/HIF-1α expression levels. In vivo, we found that incomplete RFA treatment promoted HSP70/HIF-1α and CD34 expression. Additionally, the combination of RFA and treatment targeting HSP70/HIF-1α resulted in a synergistic reduction in tumor growth compared to incomplete RFA alone. The PI3K/Akt signaling pathway is also involved in regulating HSP70/HIF-1α expression during this process. We conclude that the accelerated proliferation and angiogenesis potential of residual lung carcinomas following RFA treatment was induced by HSP70/HIF-1α, expression of which is regulated by the PI3K/Akt signaling pathway.

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.

CCL25/CCR9 Signal Promotes Migration and Invasion in Hepatocellular and Breast Cancer Cell Lines

Cancer is one of the most lethal diseases worldwide, and metastasis is the most common cause of patients' deaths. Identification and inhibition of markers involved in metastasis process in cancer cells are promising works to block metastasis and improve prognoses of patients. Chemokines are a superfamily of small, chemotactic cytokines, whose functions are based on interaction with corresponding receptors. It has been found that one of the functions of chemokines is to regulate migration and invasion abilities of lymphocytes, as well as cancer cells. Chemokine receptor 9 (CCR9) regulates trafficking of lymphocytes and cancer cell lines when interacting with its exclusive ligand chemokine 25 (CCL25). However, the mechanisms of CCL25/CCR9 signal that regulates metastasis of cancer cells are not completely known yet. In this study, we stimulated or inhibited CCL25/CCR9 signal in breast cancer cell line (MDA-MB-231) and hepatocellular cancer cell lines (HepG2 and HUH7), and found that CCL25/CCR9 signal resulted in different promotion of migration and invasion in different cell lines. These phenomena could be explained by selective regulation of several markers of epithelial-mesenchymal transition (EMT). Our findings suggested that CCL25/CCR9 signal may provide cancer cells with chemotactic abilities through influencing several EMT markers.

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.

Role of Chemokines in Non-Small Cell Lung Cancer: Angiogenesis and Inflammation

Non-small cell lung cancer (NSCLC) is one of the most common types of aggressive cancer. The tumor tissue, which shows an active angiogenesis, is composed of neoplastic and stromal cells, and an abundant inflammatory infiltrate. Angiogenesis is important to support tumor growth, while infiltrating cells contribute to the tumor microenvironment through the secretion of growth factors, cytokines and chemokines, important molecules in the progression of the disease. Chemokines are important in development, activation of the immune response, and physiological angiogenesis. Chemokines have emerged as important regulators in the pathophysiology of cancer. These molecules are involved in the angiogenesis/angiostasis balance and in the recruitment of tumor infiltrating hematopoietic cells. In addition, chemokines promote tumor cell survival, as well as the directing and establishment of tumor cells to metastasis sites. The findings summarized here emphasize the central role of chemokines as modulators of tumor angiogenesis and their potential role as therapeutic targets in the inflammatory process of NSCLC angiogenesis.

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.