CCR9-mediated signaling through β-catenin and identification of a novel CCR9 antagonist

Small HBV surface antigen drives regorafenib resistance in HCC via KIAA1429-dependent m6A modification of CCR9

A substantial body of literature, including our own, points to a connection between hepatitis B virus (HBV) infection and the development of drug resistance in hepatocellular carcinoma (HCC), particularly against sorafenib. However, the influence of HBV on resistance to regorafenib, another therapeutic agent, has been less studied. In this study, we used the GEO database (GSE87630) and clinical samples to demonstrate that C-C motif chemokine receptor 9 (CCR9) was highly expressed in HBV-related HCC and predicted poor overall survival. Its overexpression correlated with HBsAg-positive HCC patients. Both univariate and multivariable Cox regression analysis elucidated CCR9 was an independent risk factor for poor overall survival in HCC patients. Our in vitro findings further revealed that HBV structural proteins, small HBV surface antigen (SHBs), triggered an upregulation of CCR9. Functional assays showed that SHBs enhanced HCC cell proliferation, migration, and invasion, increased ABCB1 and ABCC1 expression, and promoted regorafenib resistance via CCR9. Intriguingly, overexpression of HBV plasmid and an AAV-HBV mouse model both exhibited a significant elevation in global N6-methyladenosine (m6A) levels. Further investigations revealed that SHBs elevated these m6A levels, upregulated CCR9 and stabilized CCR9 mRNA through KIAA1429-mediated m6A modification, with sites 1373 and 1496 on CCR9 mRNA being critical for modification. In conclusion, SHBs promoted HCC progression and regorafenib resistance via KIAA1429-mediated m6A modification of CCR9. Our findings suggested that CCR9 could be a potential prognostic biomarker and a valuable molecular therapeutic target of regorafenib resistance in HBV-related HCC.

Immune effector dysfunction signatures predict outcomes in patients with colorectal cancer

BACKGROUND

Immune effector dysfunction (IED) is mainly manifested as immune exhaustion and senescence, which are the primary obstacles to the success of cancer immunotherapy. In the current study, we characterized the prognostic relevance of IED signatures in patients with colorectal cancer (CRC).

METHODS

Immunohistochemistry (IHC) data of CRC tissue samples from 41 newly diagnosed patients in our clinical center (HDPH cohort) were used to investigate the prognostic importance of IED signatures. The results were validated by the RNA sequencing data of 372 CRC patients from the Cancer Genome Atlas (TCGA) database.

RESULTS

In the HDPH cohorts, high Natural Killer (NK) and CD8+ tumor-infiltrating lymphocytes (TILs) were associated with poor overall survival (OS) and relapse-free survival (RFS) in CRC patients. Optimal IED signatures, including high expression of CCR9, ISG20, and low expression of ICOS, and CACNA2D2, predicted poor OS and RFS. Moreover, high-risk scores estimated by a weighted combination of these four IED genes were associated with poor OS and RFS. Notably, risk stratification was constructed by combining risk score and tumor node metastasis (TNM) stage better than TNM stage alone in predicting OS and RFS for CRC patients. The above results were confirmed in the TCGA cohort.

CONCLUSION

CCR9, ISG20, ICOS, and CACNA2D2 were optimal IED signatures for predicting the outcomes of CRC patients, which might be a potential biomarker for prognostic stratification and designing novel CRC therapy.

Investigating novel biomarkers in uterine corpus endometrial carcinoma: in silico analysis and clinical specimens validation via RT-qPCR and immunohistochemistry

The rising incidence and mortality rate of Uterine Corpus Endometrial Carcinoma (UCEC) pose significant health concerns. CC and CXC chemokines have been linked to tumorigenesis and cancer progression. Recognizing the growing significance of CC and CXC chemokines' diagnostic and prognostic significance in diverse cancer types, our objective was to comprehensively analyze the diagnostic and prognostic values of hub genes from the CC and CXC chemokines in UCEC, utilizing both in silico and clinical samples and cell lines-based approaches. In silico analyses include STRING, Cytoscape, Cytohubba, The Cancer Genome Atlas (TCGA) datasets analysis via the UALCAN, GEPIA, OncoDB, and MuTarget, SurvivalGenie, MEXPRESS, cBioPoratal, TIMER, ENCORI, and DrugBank. Meanwhile, clinical samples and cell lines based analyses include Reverse transcription-quantitative polymerase chain reaction (RT-qPCR), targeted bisulfite sequencing (bisulfite-seq) analysis, and immunohistochemistry (IHC). Through present study, we identified CCL25 (CC motif chemokine ligand 25), CXCL10 (C-X-C motif chemokine ligand 10), CXCL12 (C-X-C motif chemokine ligand 12), and CXCL16 (C-X-C motif chemokine ligand 16) as crucial hub genes among the CC and CXC chemokines. Analyzing the expression data from TCGA, we observed a significant up-regulation of CCL25, CXCL10, and CXCL16 in UCEC samples compared to controls. In contrast, we noted a significant down-regulation of CXCL12 expression in UCEC samples. On clinical UCEC samples and cell lines analysis, the significant higher expression of CCL25, CXCL10, and CXCL16 and significant lower expression of CXCL12 were also denoted in UCEC samples than the controls via RT-qPCR and IHC analyses. Moreover, in silico analysis also confirmed the abnormal promoter methylation levels of the hub genes in TCGA UCEC samples, which was later validated by the clinical samples using targeted based bisulfite-seq analysis. In addition, various additional aspects of the CCL25, CXCL10, CXCL12, and CXCL16 have also been uncovered in UCEC during the present study. Our findings offer novel insights that contribute to the clinical utility of CCL25, CXCL10, CXCL12, and CXCL16 chemokines as potential diagnostic and prognostic biomarkers in UCEC.

Downregulation of chemokine receptor 9 facilitates CD4+CD8αα+ intraepithelial lymphocyte development

Intestinal intraepithelial lymphocytes (IELs) reside in the gut epithelial layer, where they help in maintaining intestinal homeostasis. Peripheral CD4+ T cells can develop into CD4+CD8αα+ IELs upon arrival at the gut epithelium via the lamina propria (LP). Although this specific differentiation of T cells is well established, the mechanisms preventing it from occurring in the LP remain unclear. Here, we show that chemokine receptor 9 (CCR9) expression is low in epithelial CD4+CD8αα+ IELs, but CCR9 deficiency results in CD4+CD8αα+ over-differentiation in both the epithelium and the LP. Single-cell RNA sequencing shows an enriched precursor cell cluster for CD4+CD8αα+ IELs in Ccr9-/- mice. CD4+ T cells isolated from the epithelium of Ccr9-/- mice also display increased expression of Cbfβ2, and the genomic occupancy modification of Cbfβ2 expression reveals its important function in CD4+CD8αα+ differentiation. These results implicate a link between CCR9 downregulation and Cbfb2 splicing upregulation to enhance CD4+CD8αα+ IEL differentiation.

ZIM3 activation of CCL25 expression in pulmonary metastatic nodules of osteosarcoma recruits M2 macrophages to promote metastatic growth

Tumor-associated macrophages (TAMs) play an important role in tumor growth and metastasis. However, the involvement of TAMs infiltration in pulmonary osteosarcoma (OS) metastasis remains poorly understood. Therefore, the effect of OS cells on macrophages migration was investigated by in vivo and in vitro experiments to evaluate the infiltration and mechanism of TAMs in pulmonary OS metastases. The results showed that the zinc finger protein ZIM3 was upregulated in OS cells than in osteoblasts and activated the expression of CCL25, which subsequently promoted the migration of M2 macrophages. CCL25 or ZIM3 silencing in OS cells inhibited the infiltration of M2 macrophages and the formation of pulmonary metastatic nodules in a mouse model of pulmonary OS metastasis and prolonged the survival of the mice. Furthermore, bioinformatics analyses revealed that CCL25 and ZIM3 expressions are negatively correlated with the prognosis of OS patients. In conclusion, this study found that a large number of M2 TAMs were recruited into pulmonary metastatic nodules of OS through the activation of the ZIM3-CCL25 axis in OS cells, thereby facilitating OS metastasis. Therefore, the suppression of ZIM3-CCL25-induced recruitment of M2 TAMs to the metastatic sites might be considered as a therapeutic approach to inhibit the growth of pulmonary OS metastases.

Chemokine-mucinome interplay in shaping the heterogeneous tumor microenvironment of pancreatic cancer

Pancreatic cancer (PC) is exemplified by a complex immune-suppressive, fibrotic tumor microenvironment (TME), and aberrant expression of mucins. The constant crosstalk between cancer cells, cancer-associated fibroblasts (CAFs), and the immune cells mediated by the soluble factors and inflammatory mediators including cytokines, chemokines, reactive oxygen species (ROS) promote the dynamic temporal switch towards an immune-escape phenotype in the neoplastic cells and its microenvironment that bolsters disease progression. Chemokines have been studied in PC pathogenesis, albeit poorly in the context of mucins, tumor glycocalyx, and TME heterogeneity (CAFs and immune cells). With correlative analysis from PC patients' transcriptome data, support from available literature, and scientific arguments-based speculative extrapolations in terms of disease pathogenesis, we have summarized in this review a comprehensive understanding of chemokine-mucinome interplay during stromal modulation and immune-suppression in PC. Future studies should focus on deciphering the complexities of chemokine-mediated control of glycocalyx maturation, immune infiltration, and CAF-associated immune suppression. Knowledge extracted from such studies will be beneficial to mechanistically correlate the mucin-chemokine abundance in serum versus pancreatic tumors of patients, which may aid in prognostication and stratification of PC patients for immunotherapy.

Regulation of pancreatic cancer therapy resistance by chemokines

Pancreatic ductal adenocarcinoma (PDAC) is a highly lethal malignancy characterized by high resistance and poor response to chemotherapy. In addition, the poorly immunogenic pancreatic tumors constitute an immunosuppressive tumor microenvironment (TME) that render immunotherapy-based approaches ineffective. Understanding the mechanisms of therapy resistance, identifying new targets, and developing effective strategies to overcome resistance can significantly impact the management of PDAC patients. Chemokines are small soluble factors that are significantly deregulated during PDAC pathogenesis, contributing to tumor growth, metastasis, immune cell trafficking, and therapy resistance. Thus far, different chemokine pathways have been explored as therapeutic targets in PDAC, with some promising results in recent clinical trials. Particularly, immunotherapies such as immune check point blockade therapies and CAR-T cell therapies have shown promising results when combined with chemokine targeted therapies. Considering the emerging pathological and clinical significance of chemokines in PDAC, we reviewed major chemokine-regulated pathways leading to therapy resistance and the ongoing endeavors to target chemokine signaling in PDAC. This review discusses the role of chemokines in regulating therapy resistance in PDAC and highlights the continuing efforts to target chemokine-regulated pathways to improve the efficacy of various treatment modalities.

Endogenous Pancreatic Cancer Cell PD-1 Activates MET and Induces Epithelial-Mesenchymal Transition to Promote Cancer Progression

We recently demonstrated that immune checkpoint PD-1 was endogenously expressed in pancreatic ductal adenocarcinoma (PDAC) cells. Our data indicated that PD-1 proteins are not exclusive to immune cells and have unrecognized signal transduction cascades intrinsic to cancer cells. Building on this paradigm shift, we sought to further characterize PD-1 expression in PDAC. We utilized a phospho-explorer array to identify pathways upregulated by PD-1 signaling. We discovered PD-1-mediated activation of the proto-oncogene MET in PDAC cells, which was dependent on hepatocyte growth factor (MET ligand) and not secondary to direct protein interaction. We then discovered that the PD-1/MET axis in PDAC cells regulated growth, migration, and invasion. Importantly, the PD-1/MET axis induced epithelial-to-mesenchymal transition (EMT), a well-established early oncogenic process in PDAC. We observed that combined targeting of PDAC cell PD-1 and MET resulted in substantial direct tumor cell cytotoxicity and growth inhibition in PDAC cell lines, patient-derived organoids, and patient-derived xenografts independent of cytotoxic immune responses. This is the first report of PDAC-endogenous PD-1 expression regulating MET signaling, which builds upon our growing body of work showing the oncogenic phenotype of PD-1 expression in PDAC cells is distinct from its immunogenic role. These results highlight a paradigm shift that the tumor-specific PD-1 axis is a novel target to effectively kill PDAC cells by antagonizing previously unrecognized PD-1-dependent oncogenic pathways.

A new era: tumor microenvironment in chemoresistance of pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is a solid malignant tumor with an extremely poor prognosis. Gemcitabine (GEM)-based chemotherapy remains one of the most important treatment choices for PDAC. However, either as monotherapy or as a part of the combination chemotherapy, GEM achieved only limited success in improving the survival of patients with advanced PDAC, primarily due to GEM resistance. PDAC is characterized by an extensive desmoplasia in the tumor microenvironment (TME). Increasing evidence indicates that this fibrotic TME not only actively participates in the tumor growth and spread of PDAC but also contributes to the induction of GEM resistance. Here we review the current advances of how TME components are involved in the induction of GEM resistance.

CCR9 initiates epithelial-mesenchymal transition by activating Wnt/β-catenin pathways to promote osteosarcoma metastasis

Background

Osteosarcoma (OS) patients with lung metastasis have poor prognoses, and effective therapeutic strategies for delaying or inhibiting the spread of lung metastasis from the primary OS site are lacking. Hence, it is critical to elucidate the underlying mechanisms of OS metastasis and to identify additional new effective treatment strategies for patients.

Methods

Differential expression and functional analyses were performed to identify key genes and relevant signaling pathways associated with OS lung metastasis. The expression of CCR9 in OS cell lines and tissues was measured by RT-qPCR, western blotting and immunohistochemistry. Cell migration and invasion were assessed by wound healing and Transwell Matrigel invasion assays, respectively. The regulatory relationship between CCR9 and the Wnt/β-catenin signaling pathway was further evaluated by rescue experiments.

Results

The expression of CCR9 was elevated in OS cell lines and patients with lung metastasis. CCR9 promoted MG63 and HOS cell migration and invasion by activating the Wnt/β-catenin signaling pathway. Furthermore, knockdown of CCR9 repressed epithelial–mesenchymal transition (EMT) by downregulating mesenchymal markers (N-cadherin and Vimentin) and EMT-associated transcription factors (twist and snail) and upregulating an epithelial marker (E-cadherin).

Conclusions

Our findings suggest that CCR9 promotes EMT by activating Wnt/β-catenin pathways to promote OS metastasis. CCR9 may be a promising therapeutic target to inhibit lung metastasis and serve as a novel prognostic marker for OS.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12935-021-02320-0.

Anticancer opportunities at every stage of chemokine function

The chemokine system, comprising 48 chemokines and 23 receptors, is critically involved in several hallmarks of cancer. Yet, despite extensive efforts from the pharmaceutical sector, only two drugs aimed at this system are currently approved for clinical use against cancer. To date, numerous pharmacological approaches have been developed to successfully intervene at different stages of chemokine function: (i) chemokine availability; (ii) chemokine-glycosaminoglycan binding; and (iii) chemokine receptor binding. Many of these strategies have been tested in preclinical cancer models, and some have advanced to clinical trials as potential anticancer therapies. Here we will review the strategies and growing pharmacological toolbox for manipulating the chemokine system in cancer, and address novel methods poised for future (pre)clinical testing.

Tumor microenvironment and metabolic remodeling in gemcitabine-based chemoresistance of pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is a solid malignant tumor with a very low operative rate and a poor patient prognosis. Therefore, gemcitabine (GEM)-based chemotherapy remains one of the most important treatment choices for PDAC. However, the efficacy of GEM monotherapy or GEM combination chemotherapy in improving the survival of patients with advanced PDAC is very limited, primarily due to GEM resistance. The mechanism of GEM resistance is complex and unclear. An extensive and dense fibrous matrix in the tumor microenvironment (TME) is an important feature of PDAC. Increasing evidence indicates that this fibrotic TME not only actively participates in the growth and spread of PDAC but also contributes to the induction of GEM resistance. Metabolic remodeling reduces GEM transport and synthesis in PDAC. This review focuses on the main cellular and molecular mechanisms underlying the involvement of the extracellular matrix (ECM), immune cells, and metabolic remodeling in the induction of GEM resistance; highlights the prospect of targeting the TME as an essential strategy to overcome GEM resistance; and provides new precise interventions for chemotherapy sensitization and improving the overall prognosis of patients with PDAC.

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.

Advances in research of extracellular mechanisms underlying gemcitabine resistance in pancreatic cancer

Pancreatic cancer is a solid malignant tumor with the worst prognosis worldwide, and about 90% of cases are pancreatic ductal adenocarcinoma (PDAC). Although surgical resection is the only potential way to cure PDAC, the overall survival rate after surgery is still not optimistic. Consequently, gemcitabine (GEM)-based chemotherapy is still one of the most important treatment options for PDAC. However, the survival improvement by GEM monotherapy for advanced PDAC is very limited, and GEM resistance is the key reason. The mechanism underlying gemcitabine resistance is complex and still unclear in PDAC. The extensive and dense fibrous mesenchyme in the tumor microenvironment (TME) is an important feature of PDAC. More and more evidence has shown that TME is not only an active participant in tumor growth and spread, but also a contributor to the induction of GEM resistance. This article will review the recent advances in the understanding of the cellular and molecular mechanisms underlying GEM resistance in PDAC, and discuss potential GEM chemosensitization strategies, in order to improve the effective rate of chemotherapy and the outcome.

Pancreatic Cancer Signaling Pathways, Genetic Alterations, and Tumor Microenvironment: The Barriers Affecting the Method of Treatment

Genetic alterations, especially the K-Ras mutation, carry the heaviest burden in the progression of pancreatic precursor lesions into pancreatic ductal adenocarcinoma (PDAC). The tumor microenvironment is one of the challenges that hinder the therapeutic approaches from functioning sufficiently and leads to the immune evasion of pancreatic malignant cells. Mastering the mechanisms of these two hallmarks of PDAC can help us in dealing with the obstacles in the way of treatment. In this review, we have analyzed the signaling pathways involved in PDAC development and the immune system's role in pancreatic cancer and immune checkpoint inhibition as next-generation therapeutic strategy. The direct targeting of the involved signaling molecules and the immune checkpoint molecules, along with a combination with conventional therapies, have reached the most promising results in pancreatic cancer treatment.

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.

CCR7 high expression leads to cetuximab resistance by cross-talking with EGFR pathway in PI3K/AKT signals in colorectal cancer

Cetuximab (C225), an anti-Epidermal Growth Factor receptor (EGFR) monoclonal antibody, has been widely used as a routine treatment for patients with metastatic colorectal cancer (mCRC); However, many patients who initially respond to cetuximab acquire resistance. The purpose of this study was to characterize new mechanism of acquired Cetuximab resistance. Firstly, tissue microarrays (TMA) comprising 191 CRC patients was constructed to evaluate the expression of chemokine receptor 7 (CCR7) by using immunohistochemistry (IHC). In CRC tumor tissues, CCR7 was significantly over-expressed compared with paired normal tissues (P < 0.001), and correlated with the infiltration depth (P = 0.03) and the regional lymph node metastasis (P = 0.006). Significant differences were also found in forms of overall survival (OS) and disease-free survival (DFS) between normal and tumor tissues (P < 0.001). More interestingly, EGFR was also highly expressed and co-localized with CCR7 in the tumor tissues from the patients who were insensitive to Cetuximab treatment. Secondly, we further explored the relationship between CCR7 expression and Cetuximab resistance by two CCR7 positive CRC cell lines, Caco-2 with wild-type KRAS (KRAS^wt ) and HCT116 with mutated KRAS (KRAS^G13D ). By the treatment of secondary lymphoid tissue chemokine (SLC, an exogenous high-affinity legend of CCR7), the inhibition rate of Cetuximab significantly decreased in both cells. Furthermore, the activation of SLC/CCR7 axis promoted epithelial mesenchymal transformation (EMT) in CRC tumor cells by increasing the expression of Twist and β-catenin. By using of CCR7 neutralizing antibody and p-AKT inhibitor rescued the above effects. These findings suggested that CCR7 was a key factor in those CRC patients, who have poorer reaction to Cetuximab. So combined inhibition of CCR7 and p-AKT will represent a rational therapeutic strategy for Cetuximab resistance patients.

Solvent-driven structural topology involving energetically significant intra- and intermolecular chelate ring contacts and anticancer activities of Cu(ii) phenanthroline complexes involving benzoates: experimental and theoretical studies

Two new coordination solids [Cu2(μ2-Bz)4(CH3OH)2][Cu2(η2-Bz)2(phen)2(H2O)2]·(NO3)2 (1) and [Cu(phen)(H2O)(Bz)(η2-Bz)] (2) (phen = 1,10-phenanthroline; Bz = benzoate) have been synthesized and characterized using elemental analysis, TGA, spectroscopic (IR, UV-vis-NIR and ESR) and single crystal X-ray diffraction techniques. Change of the solvent from methanol to DMF results in changes in the architectures that are triggered by a change from square pyramidal to octahedral coordination at the divalent metal centers for complexes 1 and 2 respectively. The structural topology of the complexes is established by the interplay of strong O-H⋯O and weak C-H⋯O, C-H⋯C, π-π stacking interactions. Unconventional parallel intramolecular and anti-parallel intermolecular contacts involving the chelate rings (CR) also stabilize the structures. The energetic analyses of the structures evidence that the parallel arrangement is energetically favoured which is likely due to the presence of the Cu⋯Cu cuprophilic interaction in 1 that is not established in 2. Compound 1 exhibits the highest antibacterial activity against Rhizobium leguminosarum among the tested cultures. In vitro cytotoxicity and apoptosis studies were carried out for compounds 1 and 2 on malignant Dalton's lymphoma cell line (DL). Both compounds showed a significant effect on the decrease in cell viability as compared to a control, while compound 2 induced remarkable cytotoxicity towards DL cells. Treatment also showed the appearance of membrane blebbing, chromatin condensation and fragmented nuclei which are typical characteristic features of apoptotic cell death. Furthermore, a docking study revealed that both compounds docked in the active sites of all the cancer target proteins under study. Moreover, SAR analysis revealed that oxygen and nitrogen atoms of compound 1 and the oxygen atoms of compound 2 are crucial for biological activities.

Direct therapeutic targeting of immune checkpoint PD-1 in pancreatic cancer

BACKGROUND

Pancreatic cancer (PC) hijacks innate cellular processes to promote cancer growth. We hypothesized that PC exploits PD-1/PD-L1 not only to avoid immune responses, but to directly enhance growth. We also hypothesized that immune checkpoint inhibitors (ICIs) have direct cytotoxicity in PC. We sought to elucidate therapeutic targeting of PD-1/PD-L1.

METHODS

PD-1 was assessed in PC cells, patient-derived organoids (PDOs), and clinical tissues. Then, PC cells were exposed to PD-L1 to evaluate proliferation. To test PD-1/PD-L1 signaling, cells were exposed to PD-L1 and MAPK was examined. Radio-immunoconjugates with anti-PD-1 drugs were developed to test uptake in patient-derived tumor xenografts (PDTXs). Next, PD-1 function was assessed by xenografting PD-1-knockdown cells. Finally, PC models were exposed to ICIs.

RESULTS

PD-1 expression was demonstrated in PCs. PD-L1 exposure increased proliferation and activated MAPK. Imaging PDTXs revealed uptake of radio-immunoconjugates. PD-1 knockdown in vivo revealed 67% smaller volumes than controls. Finally, ICI treatment of both PDOs/PDTXs demonstrated cytotoxicity and anti-MEK1/2 combined with anti-PD-1 drugs produced highest cytotoxicity in PDOs/PDTXs.

CONCLUSIONS

Our data reveal PCs innately express PD-1 and activate druggable oncogenic pathways supporting PDAC growth. Strategies directly targeting PC with novel ICI regimens may work with adaptive immune responses for optimal cytotoxicity.

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.

Wnt5a and CCL25 promote adult T-cell acute lymphoblastic leukemia cell migration, invasion and metastasis

Adult T-cell acute lymphoblastic leukemia (T-ALL) is a refractory leukemia. We previously showed that CCL25/CCR9 promotes T-ALL metastasis. In the present study, we assessed the effects of CCL25 on Wnt expression and the effects of Wnt5a and CCL25 on PI3K/Akt and RhoA activation. Transwell assays and mouse xenograft experiments were utilized to assess the effects of Wnt5a and CCL25 on MOLT4 cell invasion, migration and metastasis. The effects of Wnt5a on MOLT4 cell actin polarization and pseudopodium formation were examined using laser scanning confocal microscopy and scanning electron microscopy. CCL25 induced Wnt5a expression in MOLT4 cells by promoting protein kinase C (PKC) expression and activation. Wnt5a promoted MOLT4 cell migration, invasion, actin polarization, and lamellipodium and filopodia formation via PI3K/Akt-RhoA pathway activation. These effects were rescued by PI3K/Akt or RhoA knockdown or inhibition. Additionally, Wnt5a in cooperation with CCL25 promoted MOLT4 cell mouse liver metastasis and stimulated RhoA activation. These results show that CCL25/CCR9 upregulates Wnt5a by promoting PKC expression and activation in MOLT4 cells. This in turn promotes cell migration and invasion via PI3K/Akt-RhoA signaling, enhancing cell polarization and pseudopodium formation. These findings indicate that the PI3K/Akt-RhoA pathway is likely responsible for Wnt5a-induced adult T-ALL cell migration and invasion.

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.

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.

CCR9-mediated signaling through β-catenin and identification of a novel CCR9 antagonist

Elevated levels of chemokine receptor CCR9 expression in solid tumors may contribute to poor patient prognosis. In this study, we characterized a novel CCR9-mediated pathway that promotes pancreatic cancer cell invasion and drug resistance, indicating that CCR9 may play a critical role in cancer progression through activation of β-catenin. We noted that the CCL25/CCR9 axis in pancreatic cancer cells induced the activation of β-catenin, which enhanced cell proliferation, invasion, and drug resistance. CCR9-mediated activation of β-catenin and the resulting downstream effects were effectively inhibited by blockade of the PI3K/AKT pathway, but not by antagonism of Wnt. Importantly, we discovered that CCR9/CCL25 increased the lethal dose of gemcitabine, suggesting decreased efficacy of anti-cancer drugs with CCR9 signaling. Through in silico computational modeling, we identified candidate CCR9 antagonists and tested their effects on CCR9/β-catenin regulation of cell signaling and drug sensitivity. When combined with gemcitabine, it resulted in synergistic cytotoxicity. Our results show that CCR9/β-catenin signaling enhances pancreatic cancer invasiveness and chemoresistance, and may be a highly novel therapeutic target.