CXCL12-CXCR7 axis contributes to the invasive phenotype of pancreatic cancer

Targeting the Cancer-Neuronal Crosstalk in the Pancreatic Cancer Microenvironment

Pancreatic ductal adenocarcinoma (PDAC) represents one of the most aggressive solid tumors with a dismal prognosis and an increasing incidence. At the time of diagnosis, more than 85% of patients are in an unresectable stage. For these patients, chemotherapy can prolong survival by only a few months. Unfortunately, in recent decades, no groundbreaking therapies have emerged for PDAC, thus raising the question of how to identify novel therapeutic druggable targets to improve prognosis. Recently, the tumor microenvironment and especially its neural component has gained increasing interest in the pancreatic cancer field. A histological hallmark of PDAC is perineural invasion (PNI), whereby cancer cells invade surrounding nerves, providing an alternative route for metastatic spread. The extent of PNI has been positively correlated with early tumor recurrence and reduced overall survival. Multiple studies have shown that mechanisms involved in PNI are also involved in tumor spread and pain generation. Targeting these pathways has shown promising results in alleviating pain and reducing PNI in preclinical models. In this review, we will describe the mechanisms and future treatment strategies to target this mutually trophic interaction between cancer cells to open novel avenues for the treatment of patients diagnosed with PDAC.

New Potential MicroRNA Biomarkers in Human Immunodeficiency Virus Elite Controllers, Human Immunodeficiency Virus Infections, and Coinfections with Hepatitis B Virus or Hepatitis C Virus

INTRODUCTION

This research aimed to evaluate the specific microRNA (miRNA) including miR-17-5p, miRN-140-3p miR-191-5p, miR-200c-3p, and miR-N367 and cellular factors (p21, SDF-1, XCL1, CCL-2, and IL-2) in controlling replication of human immunodeficiency virus (HIV) in ECs.

METHODS

The expression of miRNAs was assessed between healthy control groups and patient groups including ART-naïve HIV, HIV ART, ECs, and coinfection (HIV-HBV and HIV-HCV) via real-time PCR technique. Besides, the expression level of the nef gene and cellular factors were assessed by the ELISA method. The differences in the level of cellular factors and selected miRNAs between study groups were analyzed using the Kruskal-Wallis H or one-way ANOVA test. In addition, the potential of selected miRNAs as biomarkers for discriminating study groups was assessed by the receiver-operator characteristic (ROC) curve analysis.

RESULTS

Some miRNAs in ECs, HIV ART, and healthy controls have similar expression patterns, whereas a miRNA expression profile of patient groups significantly differed compared to EC and control groups. According to ROC curve analyses, the miR-17-5p, miR-140-3p miR-191-5p, miR-200c-3p, and miR-N367 can be served as biomarkers for discriminating ECs from ART-naïve HIV-infected groups. There was a significant correlation between some miRNAs and cellular factors/the viral load as well.

CONCLUSION

This report demonstrated a differentiation in the expression of selected immunological factors and cellular/viral miRNAs in ECs compared to other patient groups. Some miRNAs and cellular factors are involved in the viral replication control, immune response/modulation and can be used as biomarkers for diagnosis of ECs and differentiation with other groups. Differential expression of these miRNAs and cellular factors in different stages of HIV infection can help in finding novel ways for infection control.

Photodynamic Stromal Depletion in Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is one of the deadliest solid malignancies, with a five-year survival of less than 10%. The resistance of the disease and the associated lack of therapeutic response is attributed primarily to its dense, fibrotic stroma, which acts as a barrier to drug perfusion and permits tumour survival and invasion. As clinical trials of chemotherapy (CT), radiotherapy (RT), and targeted agents have not been successful, improving the survival rate in unresectable PDAC remains an urgent clinical need. Photodynamic stromal depletion (PSD) is a recent approach that uses visible or near-infrared light to destroy the desmoplastic tissue. Preclinical evidence suggests this can resensitise tumour cells to subsequent therapies whilst averting the tumorigenic effects of tumour-stromal cell interactions. So far, the pre-clinical studies have suggested that PDT can successfully mediate the destruction of various stromal elements without increasing the aggressiveness of the tumour. However, the complexity of this interplay, including the combined tumour promoting and suppressing effects, poses unknowns for the clinical application of photodynamic stromal depletion in PDAC.

Liposome-based diagnostic and therapeutic applications for pancreatic cancer

Pancreatic cancer is one of the harshest and most challenging cancers to treat, often labeled as incurable. Chemotherapy continues to be the most popular treatment yet yields a very poor prognosis. The main barriers such as inefficient drug penetration and drug resistance, have led to the development of drug carrier systems. The benefits, ease of fabrication and modification of liposomes render them as ideal future drug delivery systems. This review delves into the versatility of liposomes to achieve various mechanisms of treatment for pancreatic cancer. Not only are there benefits of loading chemotherapy drugs and targeting agents onto liposomes, as well as mRNA combined therapy, but liposomes have also been exploited for immunotherapy and can be programmed to respond to photothermal therapy. Multifunctional liposomal formulations have demonstrated significant pre-clinical success. Functionalising drug-encapsulated liposomes has resulted in triggered drug release, specific targeting, and remodeling of the tumor environment. Suppressing tumor progression has been achieved, due to their ability to more efficiently and precisely deliver chemotherapy. Currently, no multifunctional surface-modified liposomes are clinically approved for pancreatic cancer thus we aim to shed light on the trials and tribulations and progress so far, with the hope for liposomal therapy in the future and improved patient outcomes. STATEMENT OF SIGNIFICANCE: Considering that conventional treatments for pancreatic cancer are highly associated with sub-optimal performance and systemic toxicity, the development of novel therapeutic strategies holds outmost relevance for pancreatic cancer management. Liposomes are being increasingly considered as promising nanocarriers for providing not only an early diagnosis but also effective, highly specific, and safer treatment, improving overall patient outcome. This manuscript is the first in the last 10 years that revises the advances in the application of liposome-based formulations in bioimaging, chemotherapy, phototherapy, immunotherapy, combination therapies, and emergent therapies for pancreatic cancer management. Prospective insights are provided regarding several advantages resulting from the use of liposome technology in precision strategies, fostering new ideas for next-generation diagnosis and targeted therapies of pancreatic cancer.

The role of CXCL12 axis in pancreatic cancer: New biomarkers and potential targets

Introduction

Chemokines are small, secreted peptides involved in the mediation of the immune cell recruitment. Chemokines have been implicated in several diseases including autoimmune diseases, viral infections and also played a critical role in the genesis and development of several malignant tumors. CXCL12 is a homeostatic CXC chemokine involved in the process of proliferation, and tumor spread. Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive tumors, that is still lacking effective therapies and with a dramatically poor prognosis.

Method

We conducted a scientific literature search on Pubmed and Google Scholar including retrospective, prospective studies and reviews focused on the current research elucidating the emerging role of CXCL12 and its receptors CXCR4 - CXCR7 in the pathogenesis of pancreatic cancer.

Results

Considering the mechanism of immunomodulation of the CXCL12-CXCR4-CXCR7 axis, as well as the potential interaction with the microenvironment in the PDAC, several combined therapeutic approaches have been studied and developed, to overcome the "cold" immunological setting of PDAC, like combining CXCL12 axis inhibitors with anti PD-1/PDL1 drugs.

Conclusion

Understanding the role of this chemokine's axis in disease initiation and progression may provide the basis for developing new potential biomarkers as well as therapeutic targets for related pancreatic cancers.

CXCR4-CXCL12-CXCR7 and PD-1/PD-L1 in Pancreatic Cancer: CXCL12 Predicts Survival of Radically Resected Patients

Pancreatic ductal adenocarcinoma (PDAC) is currently the most deadly cancer. Although characterized by 5-20% of neoplastic cells in the highly fibrotic stroma, immunotherapy is not a valid option in PDAC treatment. As CXCR4-CXCL12 regulates tumor invasion and T-cell access and PD-1/PD-L1 controls immune tolerance, 76 PDACs were evaluated for CXCR4-CXCL12-CXCR7 and PD-1/PD-L1 in the epithelial and stromal component. Neoplastic CXCR4 and CXCL12 discriminated PDACs for recurrence-free survival (RFS), while CXCL12 and CXCR7 discriminated patients for cancer-specific survival (CSS). Interestingly, among patients with radical resection (R0), high tumor CXCR4 clustered patients with worse RFS, high CXCL12 identified poor prognostic patients for both RFS and CSS, while stromal lymphocytic-monocytic PD-L1 associated with improved RFS and CSS. PD-1 was only sporadically expressed (<1%) in focal lymphocyte infiltrate and does not impact prognosis. In multivariate analysis, tumoral CXCL12, perineural invasion, and AJCC lymph node status were independent prognostic factors for RFS; tumoral CXCL12, AJCC Stage, and vascular invasion were independent prognostic factors for CSS. CXCL12's poor prognostic meaning was confirmed in an additional perspective-independent 13 fine-needle aspiration cytology advanced stage-PDACs. Thus, CXCR4-CXCL12 evaluation in PDAC identifies prognostic categories and could orient therapeutic approaches.

MicroRNA-200b-3p restrains gastric cancer cell proliferation, migration, and invasion via C-X-C motif chemokine ligand 12/CXC chemokine receptor 7 axis

This study was conducted to investigate the impact of microRNA (miR)-200b-3p on viability, migration, and invasion of gastric cancer (GC) cells and its mechanism. Quantitative real-time PCR (qRT-PCR) was conducted to measure miR-200b-3p expression in GC tissues and cells; besides, the relationship between miR-200b-3p expression and overall survival time (OS) was analyzed with OncomiR database; cell counting kit-8 (CCK-8), colony formation assay, flow cytometry, scratch healing assay, and Transwell assay were performed to detect the proliferation, cell cycle progression, migration, and invasion of GC cells; a lung metastasis model in nude mice was used to examine the effect of miR-200b-3p on the metastasis of GC cells in vivo; the interplay between miR-200b-3p and C-X-C motif chemokine ligand 12 (CXCL12) mRNA 3’ UTR was predicted by bioinformatics and verified with a dual-luciferase reporter gene assay; besides, the expression of CXCL12 and CXC chemokine receptor 7 (CXCR7) was probed by Western blot. It was found that miR-200b-3p expression was down-regulated in GC tissues, which was remarkably associated with the lymph node metastasis and decrease of differentiation of GC; transfection with miR-200b-3p mimics restrained the growth, migration, and invasion of GC cells in vitro, induced cell cycle arrest, and inhibited CXCL12 and CXCR7 expression levels; transfection of miR-200b-3p inhibitors worked oppositely in vitro and promoted lung metastasis in vivo. CXCL12 was confirmed as the downstream target of miR-200b-3p and was negatively modulated by miR-200b-3p. In conclusion, miR-200b-3p inhibited GC progression via regulating CXCL12/CXCR7 axis.

Cancer-Associated Fibroblasts and Tumor Cells in Pancreatic Cancer Microenvironment and Metastasis: Paracrine Regulators, Reciprocation and Exosomes

Simple Summary

Cancer-associated fibroblasts in the stromal tumor microenvironment play a key role in cancer progression, invasion, metastasis, and therapy resistance. Cancer-associated fibroblasts communicate with tumor cells through diverse factors, such as growth factors, hedgehog proteins, cytokines, and chemokines, regulating signaling activity in paracrine as well as paracrine-reciprocal ways. Furthermore, cancer-associated fibroblasts, not only tumor cells, secrete exosomes that drive pre-metastatic niche formation and metastasis.

Abstract

Pancreatic cancer is currently the fourth leading cause of cancer deaths in the United States, and the overall 5 year survival rate is still only around 10%. Pancreatic cancer exhibits a remarkable resistance to established therapeutic options such as chemotherapy and radiotherapy, in part due to the dense stromal tumor microenvironment, where cancer-associated fibroblasts are the major stromal cell type. Cancer-associated fibroblasts further play a key role in cancer progression, invasion, and metastasis. Cancer-associated fibroblasts communicate with tumor cells, not only through paracrine as well as paracrine-reciprocal signaling regulators but also by way of exosomes. In the current manuscript, we discuss intercellular mediators between cancer-associated fibroblasts and pancreatic cancer cells in a paracrine as well as paracrine-reciprocal manner. Further recent findings on exosomes in pancreatic cancer and metastasis are summarized.

TLR2 and TLR4 Signaling Pathways and Gastric Cancer: Insights from Transcriptomics and Sample Validation

Background

Pattern recognition receptors, especially toll-like receptors (TLRs), as the first line of defense for pathogen detection, were found to be associated with H.¬ pylori infection and gastric cancer (GC). However, the expression levels of TLRs, i.e. TLR2 and TLR4, as the main receptors sensed by H.¬ pylori, still remain largely ambiguous. We aimed to investigate the patterns of key transcripts of TLR2 and TLR4 in 100 GC transcriptome data. Additionally, we evaluated TLR2 and TLR4 gene expressions in gastric biopsies of Iranian GC patients, in order to validate RNA-seq outputs.

Methods

For this study, 100 runs of GC samples and controls were processed and analyzed using map read to reference. Differential gene expression method was used to distinguish between GC and normal samples in the expression of TLRs and other innate immune molecules. Also, using qRT-PCR assay, transcripts of TLRs molecules for 15 GC and 15 control samples were analyzed based on the analysis of variance and least significant differences.

Results

The results clearly showed that all signaling pathways molecules of TLR4, especially TLR4 (p = 0.019), NF-κB (p ¬= 0.047), IL-1β (p = 0.0096), and TNF-α (p = 0.048), were upregulated in a cancerous condition in different parts and at various stages of GC.

Conclusion

Our findings suggested that molecules involved in inflammation, including TLR4 and its related pro-inflammatory cytokines, may be responsible for the development and progression of GC. Accordingly, the control of H. pylori infection reduces inflammation in the gastric system and can play an important role in preventing gastrointestinal disorders.

Effects of SDF-1/CXCR7 on the Migration, Invasion and Epithelial-Mesenchymal Transition of Gastric Cancer Cells

We found that SDF-1/CXCR7 axis played an important role in the growth and proliferation of gastric cancer in the previous studies. The objectives of this study were to explore the effects of SDF-1/CXCR7 on the metastatic ability of gastric cancer cells and the possible mechanisms. CXCR7 expression in SGC-7901 gastric cancer cells was stably knocked down via lentiviral vectors. The cell migration and invasion abilities were detected by transwell migration and invasion assays. The expressions of matrix metalloproteinase 2 (MMP-2), MMP-9, vascular endothelial growth factor (VEGF), epithelial-mesenchymal transition (EMT) markers and Akt phosphorylation were detected with real-time PCR and/or western blot. We found that SDF-1 markedly enhanced the migration and invasion abilities of SGC-7901 gastric cancer cells; CXCR7 knockdown inhibited these effects. SDF-1/CXCR7 increased the expressions of MMP-2, MMP-9 and VEGF. SDF-1/CXCR7 also downregulated E-cadherin expression but upregulated N-cadherin, vimentin and Snail expressions, suggesting that SDF-1/CXCR7 could promote the development of EMT in gastric cancer cells. Furthermore, SDF-1/CXCR7 could promote Akt phosphorylation. Our results indicated that SDF-1/CXCR7 enhanced the migration, invasion and EMT of gastric cancer cells and thus CXCR7 supression may be a strategy for inhibiting gastric cancer metastasis.

Translational challenges in pancreatic neuroendocrine tumor immunotherapy

Pancreatic neuroendocrine tumors are rare types of pancreatic cancer formed from islet cells of pancreas. Clinical presentation of pancreatic neuroendocrine tumors depends on both tumor progression and hormone secretion status, which generate several complications in both diagnosis and treatment. Despite numerous strategies, treatment of patients with pancreatic neuroendocrine tumors still needs improvement. It is suggested that immune response modulation may be essential in the regulation of pancreatic neuroendocrine tumor progression and patient's symptomology. Accumulating evidence indicates that immunotherapy seems to be a promising treatment option for patients with pancreatic neuroendocrine tumors. Nevertheless, several challenges in pre-clinical and clinical studies are present. This review provides knowledge about microenvironment of pancreatic neuroendocrine tumors including significance of cytokine and chemokine as well as specific immune cell types. Additionally, in vitro and in vivo models of pancreatic neuroendocrine tumors and translational challenges are highlighted.

Dramatic Reduction of Distant Pancreatic Metastases Using Local Light Activation of Verteporfin with Nab-Paclitaxel

Despite substantial drug development efforts, pancreatic adenocarcinoma (PDAC) remains a difficult disease to treat, and surgical resection is the only potentially curative option. Unfortunately, 80% of patients are ineligible for surgery due to the presence of invasive disease and/or distant metastases at the time of diagnosis. Treatment strategies geared towards reclassifying these patients as surgical candidates by reducing metastatic burden represents the most promising approach to improve long-term survival. We describe a photodynamic therapy (PDT) based approach that, in combination with the first-line chemotherapeutic nab-paclitaxel, effectively addresses distant metastases in three separate orthotopic PDAC models in immunodeficient mice. In addition to effectively controlling local tumor growth, PDT plus nab-paclitaxel primes the tumor to elicit systemic effects and reduce or abrogate metastases. This combination dramatically inhibits (up to 100%) the eventual development of metastases in models of early stage PDAC, and completely eliminates metastasis in 55% of animals with already established distant disease in late-stage models. Our findings suggest that this light activation process initiates local biological and/or physiological changes within the tumor microenvironment that can be leveraged to treat both localized and distant disease, and potentially reclassify patients with previously inoperable disease as surgical candidates.

Chemokine signaling in cancer-stroma communications

Cancer is a multi-faceted disease in which spontaneous mutation(s) in a cell leads to the growth and development of a malignant new organ that if left undisturbed will grow in size and lead to eventual death of the organism. During this process, multiple cell types are continuously releasing signaling molecules into the microenvironment, which results in a tangled web of communication that both attracts new cell types into and reshapes the tumor microenvironment as a whole. One prominent class of molecules, chemokines, bind to specific receptors and trigger directional, chemotactic movement in the receiving cell. Chemokines and their receptors have been demonstrated to be expressed by almost all cell types in the tumor microenvironment, including epithelial, immune, mesenchymal, endothelial, and other stromal cells. This results in chemokines playing multifaceted roles in facilitating context-dependent intercellular communications. Recent research has started to shed light on these ligands and receptors in a cancer-specific context, including cell-type specificity and drug targetability. In this review, we summarize the latest research with regards to chemokines in facilitating communication between different cell types in the tumor microenvironment.

Effect of Fucoxanthinol on Pancreatic Ductal Adenocarcinoma Cells from an N-Nitrosobis(2-oxopropyl)amine-initiated Syrian Golden Hamster Pancreatic Carcinogenesis Model

BACKGROUND/AIM

Fucoxanthinol (FxOH) is a marine carotenoid metabolite with potent anti-cancer activity. However, little is known about the efficacy of FxOH in pancreatic cancer. In the present study, we investigated the inhibitory effect of FxOH on six types of cells cloned from N-nitrosobis(2-oxopropyl)amine (BOP)-induced hamster pancreatic cancer (HaPC) cells.

MATERIALS AND METHODS

FxOH action and its molecular mechanisms were investigated in HaPC cells using flow-cytometry, comprehensive gene array, and western blotting analyses.

RESULTS

FxOH (5.0 μM) significantly suppressed the growth of four out of six types of HaPC cells. Moreover, FxOH significantly suppressed cell cycle, chemokine, integrin, actin polymerization, microtubule organization and PI3K/AKT and TGF-β signals, and activated caspase-3 followed by apoptosis and anoikis induction in HaPC-5 cells.

CONCLUSION

FxOH may have a high potential as a cancer chemopreventive agent in a hamster pancreatic carcinogenesis model.

Functions and mechanisms of chemokine receptor 7 in tumors of the digestive system

Chemokine (C-X-C motif) receptor 7 (CXCR7), recently termed ACKR3, belongs to the G protein-coupled cell surface receptor family, binds to stromal cell-derived factor-1 [SDF-1, or chemokine (C-X-C motif) ligand 12] or chemokine (C-X-C motif) ligand 11, and is the most common chemokine receptor expressed in a variety of cancer cells. SDF-1 binds to its receptor chemokine (C-X-C motif) receptor 4 (CXCR4) and regulates cell proliferation, survival, angiogenesis and migration. In recent years, another new receptor for SDF-1, CXCR7, has been discovered, and CXCR7 has also been found to be expressed in a variety of tumor cells and tumor-related vascular endothelial cells. Many studies have shown that CXCR7 can promote the growth and metastasis of a variety of malignant tumor cells. Unlike CXCR4, CXCR7 exhibits a slight modification in the DRYLAIV motif and does not induce intracellular Ca²⁺ release following ligand binding, which is essential for recruiting and activating G proteins. CXCR7 is generally thought to work in three ways: (1) Recruiting β-arrestin 2; (2) Heterodimerizing with CXCR4; and (3) Acting as a “scavenger” of SDF-1, thus lowering the level of SDF-1 to weaken the activity of CXCR4. In the present review, the expression and role of CXCR7, as well as its prognosis in cancers of the digestive system, were investigated.

FUNCTION-ON-SCALAR QUANTILE REGRESSION WITH APPLICATION TO MASS SPECTROMETRY PROTEOMICS DATA

Mass spectrometry proteomics, characterized by spiky, spatially heterogeneous functional data, can be used to identify potential cancer biomarkers. Existing mass spectrometry analyses utilize mean regression to detect spectral regions that are differentially expressed across groups. However, given the inter-patient heterogeneity that is a key hallmark of cancer, many biomarkers are only present at aberrant levels for a subset of, not all, cancer samples. Differences in these biomarkers can easily be missed by mean regression, but might be more easily detected by quantile-based approaches. Thus, we propose a unified Bayesian framework to perform quantile regression on functional responses. Our approach utilizes an asymmetric Laplace working likelihood, represents the functional coefficients with basis representations which enable borrowing of strength from nearby locations, and places a global-local shrinkage prior on the basis coefficients to achieve adaptive regularization. Different types of basis transform and continuous shrinkage priors can be used in our framework. A scalable Gibbs sampler is developed to generate posterior samples that can be used to perform Bayesian estimation and inference while accounting for multiple testing. Our framework performs quantile regression and coefficient regularization in a unified manner, allowing them to inform each other and leading to improvement in performance over competing methods as demonstrated by simulation studies. We also introduce an adjustment procedure to the model to improve its frequentist properties of posterior inference. We apply our model to identify proteomic biomarkers of pancreatic cancer that are differentially expressed for a subset of cancer patients compared to the normal controls, which were missed by previous mean-regression based approaches. Supplementary materials for this article are available online.

Prognostic and predictive value of a five-molecule panel in resected pancreatic ductal adenocarcinoma: A multicentre study

Background

Pancreatic ductal adenocarcinoma (PDAC) has a devastating prognosis. The performance of clinicopathologic parameters and molecules as prognostic factors remains limited and inconsistent. The present study aimed to construct a multi-molecule biomarker panel to more accurately predict post-resectional prognosis of PDAC patients.

Methods

Firstly, a novel computational strategy integrating prognostic evidence from omics and literature on the basis of bioinformatics prediction (CIPHER) to generate the network, was designed to systematically identify potential high-confidence PDAC-related prognostic candidates. After specimens from 605 resected PDAC patients were retrospectively collected, 23 candidates were detected immunohistochemically in tissue-microarrays for the development cohort to construct a multi-molecule panel. Lastly, the panel was validated in two independent cohorts.

Findings

According to the constructed five-molecule panel, disease-specific survival (DSS) was significantly poorer in high-risk patients than in low-risk ones in development cohort (HR 2.15, 95%CI 1.51–3.05, P<0.0001; AUC 0.67). In two validation cohorts, similar significant differences between the two groups were also observed (HR 3.18 and 3.31, 95%CI 1.89–5.37 and 1.78–6.16, All P<0.0001; AUC 0.72 and 0.73). In multivariate analyses, this panel was the sole prognosticator that was significant in each cohort. Furthermore, its predictive power for long-term survival, higher than its individual constituents, could be largely enhanced by combination with traditional clinicopathological variables. Finally, adjuvant chemotherapy (ACT) correlated with better DSS only in high-risk patients, uni- and multi-variately, in all the cohorts.

Interpretation

The novel prognostic panel developed by a systematically network-based strategy presents strong ability in prediction of post-resectional survival of PDAC patients. Furthermore, panel-defined high-risk patients might benefit more from ACT.

Vitamin D Receptor Activation and Photodynamic Priming Enables Durable Low-dose Chemotherapy

Patients with cancer often confront the decision of whether to continue high-dose chemotherapy at the expense of cumulative toxicities. Reducing the dose of chemotherapy regimens while preserving efficacy is sorely needed to preserve the performance status of these vulnerable patients, yet has not been prioritized. Here, we introduce a dual pronged approach to modulate the microenvironment of desmoplastic pancreatic tumors and enable significant dose deescalation of the FDA-approved chemotherapeutic nanoliposomal irinotecan (nal-IRI) without compromising tumor control. We demonstrate that light-based photodynamic priming (PDP) coupled with vitamin D3 receptor (VDR) activation within fibroblasts increases intratumoral nal-IRI accumulation and suppresses protumorigenic CXCL12/CXCR7 crosstalk. Combined photodynamic and biochemical modulation of the tumor microenvironment enables a 75% dose reduction of nal-IRI while maintaining treatment efficacy, resulting in improved tolerability. Modifying the disease landscape to increase the susceptibility of cancer, via preferentially modulating fibroblasts, represents a promising and relatively underexplored strategy to enable dose deescalation. The approach presented here, using a combination of three clinically available therapies with nonoverlapping toxicities, can be rapidly translated with minimal modification to treatment workflow, and challenges the notion that significant improvements in chemotherapy efficacy can only be achieved at the expense of increased toxicity.

The CXCL12-CXCR4/CXCR7 axis as a mechanism of immune resistance in gastrointestinal malignancies

Single agent checkpoint inhibitor therapy has not been effective for most gastrointestinal solid tumors, but combination therapy with drugs targeting additional immunosuppressive pathways is being attempted. One such pathway, the CXCL12-CXCR4/CXCR7 chemokine axis, has attracted attention due to its effects on tumor cell survival and metastasis as well as immune cell migration. CXCL12 is a small protein that functions in normal hematopoietic stem cell homing in addition to repair of damaged tissue. Binding of CXCL12 to CXCR4 leads to activation of G protein signaling kinases such as P13K/mTOR and MEK/ERK while binding to CXCR7 leads to β-arrestin mediated signaling. While some gastric and colorectal carcinoma cells have been shown to make CXCL12, the primary source in pancreatic cancer and peritoneal metastases is cancer-associated fibroblasts. Binding of CXCL12 to CXCR4 and CXCR7 on tumor cells leads to anti-apoptotic signaling through Bcl-2 and survivin upregulation, as well as promotion of the epithelial-to-mesechymal transition through the Rho-ROCK pathway and alterations in cell adhesion molecules. High levels of CXCL12 seen in the bone marrow, liver, and spleen could partially explain why these are popular sites of metastases for many tumors. CXCL12 is a chemoattractant for lymphocytes at lower levels, but becomes chemorepellant at higher levels; it is unclear exactly what gradient exists in the tumor microenvironment and how this influences tumor-infiltrating lymphocytes. AMD3100 (Plerixafor or Mozobil) is a small molecule CXCR4 antagonist and is the most frequently used drug targeting the CXCL12-CXCR4/CXCR7 axis in clinical trials for gastrointestinal solid tumors currently. Other small molecules and monoclonal antibodies against CXCR4 are being trialed. Further understanding of the CXCL12- CXCR4/CXCR7 chemokine axis in the tumor microenvironment will allow more effective targeting of this pathway in combination immunotherapy.

Antibodies Targeting Chemokine Receptors CXCR4 and ACKR3

Dysregulation of the chemokine system is implicated in a number of autoimmune and inflammatory diseases, as well as cancer. Modulation of chemokine receptor function is a very promising approach for therapeutic intervention. Despite interest from academic groups and pharmaceutical companies, there are currently few approved medicines targeting chemokine receptors. Monoclonal antibodies (mAbs) and antibody-based molecules have been successfully applied in the clinical therapy of cancer and represent a potential new class of therapeutics targeting chemokine receptors belonging to the class of G protein-coupled receptors (GPCRs). Besides conventional mAbs, single-domain antibodies and antibody scaffolds are also gaining attention as promising therapeutics. In this review, we provide an extensive overview of mAbs, single-domain antibodies, and other antibody fragments targeting CXCR4 and ACKR3, formerly referred to as CXCR7. We discuss their unique properties and advantages over small-molecule compounds, and also refer to the molecules in preclinical and clinical development. We focus on single-domain antibodies and scaffolds and their utilization in GPCR research. Additionally, structural analysis of antibody binding to CXCR4 is discussed. SIGNIFICANCE STATEMENT: Modulating the function of GPCRs, and particularly chemokine receptors, draws high interest. A comprehensive review is provided for monoclonal antibodies, antibody fragments, and variants directed at CXCR4 and ACKR3. Their advantageous functional properties, versatile applications as research tools, and use in the clinic are discussed.

Decursin inhibits tumor growth, migration, and invasion in gastric cancer by down-regulating CXCR7 expression

CXC chemokine receptor 7 (CXCR7) is highly expressed in various type of cancers and promotes cancer progression and metastasis. However, the biological role and regulation of CXCR7 in gastric cancer remains unclear, and little is known about compounds that modulate CXCR7. Here, we investigated the role of CXCR7 in gastric tumorigenesis, and the effects of decursin, which is derived from Angelica gigas Nakai, on CXCR7. Our results showed that CXCR7 significantly promoted growth of gastric cancer cells and increased migration and invasion, which was mediated by the STAT3/c-Myc pathway. We also confirmed that decursin had an antitumor effect through down-regulating the expression of CXCR7 in gastric cancer. Furthermore, apoptotic cell death was induced through the reduction of anti-apoptotic factors such as Bcl-2 in vitro and in vivo. Our findings show that CXCR7 in gastric cancer promotes cancer progression through the STAT3/c-Myc pathway and that decursin is a natural compound that may target CXCR7 in gastric cancer treatment.

CXCR7 contributes to the aggressive phenotype of cholangiocarcinoma cells

Development of cholangiocarcinoma (CCA) is dependent on a cross-talk with stromal cells, which release different chemokines including CXCL12, that interacts with two different receptors, CXCR4 and CXCR7. The aim of the present study was to investigate the role of CXCR7 in CCA cells. CXCR7 is overexpressed by different CCA cell lines and in human CCA specimens. Knock-down of CXCR7 in HuCCT-1 cells reduced migration, invasion, and CXCL12-induced adhesion to collagen I. Survival of CCA was also reduced in CXCR7-silenced cells. The ability of CXCL12 to induce cell migration and survival was also blocked by CCX733, a CXCR7 antagonist. Similar effects of CXCR7 activation were observed in CCLP-1 cells and in primary iCCA cells. Enrichment of tumor stem-like cells by a 3D culture system resulted in increased CXCR7 expression compared to cells grown in monolayers, and genetic knockdown of CXCR7 robustly reduced sphere formation both in HuCCT-1 and in CCLP-1 cells. In HuCCT-1 cells CXCR7 was found to interact with β-arrestin 2, which was necessary to mediate CXCL12-induced migration, but not survival. In conclusion, CXCR7 is widely expressed in CCA, and contributes to the aggressive phenotype of CCA cells, inducing cell migration, invasion, adhesion, survival, growth and stem cell-like features. Cell migration induced by CXCR7 requires interaction with β-arrestin 2.

miR-101 Represses T-Cell Acute Lymphoblastic Leukemia by Targeting CXCR7/STAT3 Axis

Although miR-101 is involved in the development and progression of T-cell acute lymphoblastic leukemia (T-ALL), the underlying molecular mechanisms remain unclear. In this article, we report that miR-101 expression was inversely correlated with CX chemokine receptor 7 (CXCR7) level in T-ALL. Introducing miR-101 inhibited T-ALL cell proliferation and invasion in vitro and suppressed tumor growth and lung metastasis in vivo. CXCR7 was identified as a direct target of miR-101. The inhibitory effects of miR-101 were mimicked and counteracted by CXCR7 depletion and overexpression, respectively. Mechanistically, miR-101 targets CXCR7/STAT3 axis to reduce T-ALL growth and metastasis. Overall, these findings implied the potential application of miR-101 and CXCR7 in T-ALL treatment.

Conophylline suppresses pancreatic cancer desmoplasia and cancer-promoting cytokines produced by cancer-associated fibroblasts

Despite recent advances in cancer treatment, pancreatic cancer is a highly malignant tumor type with a dismal prognosis and it is characterized by dense desmoplasia in the cancer tissue. Cancer-associated fibroblasts (CAF) are responsible for this fibrotic stroma and promote cancer progression. We previously reported that a novel natural compound conophylline (CnP) extracted from the leaves of a tropical plant reduced liver and pancreatic fibrosis by suppression of stellate cells. However, there have been no studies to investigate the effects of CnP on CAF, which is the aim of this work. Here, we showed that CAF stimulated indicators of pancreatic cancer malignancy, such as proliferation, invasiveness, and chemoresistance. We also showed that CnP suppressed CAF activity and proliferation, and inhibited the stimulating effects of CAF on pancreatic cancer cells. Moreover, CnP strongly decreased the various cytokines involved in cancer progression, such as interleukin (IL)-6, IL-8, C-C motif chemokine ligand 2 (CCL2), and C-X-C motif chemokine ligand 12 (CXCL12), secreted by CAF. In vivo, CAF promoted tumor proliferation and desmoplastic formation in a mouse xenograft model, CnP reduced desmoplasia of tumors composed of pancreatic cancer cells + CAF, and combination therapy of CnP with gemcitabine remarkably inhibited tumor proliferation. Our findings suggest that CnP is a promising therapeutic strategy of combination therapy with anticancer drugs to overcome refractory pancreatic cancers.

Prognostic significance of CXCR7 in cancer patients: a meta-analysis

Background

CXC chemokine receptor 7 (CXCR7) is frequently overexpressed in a variety of tumors. Nevertheless, whether CXCR7 can be used as a tumor prognosis marker has not been systematically assessed. The current meta-analysis was performed to obtain an accurate evaluation of the relationship between CXCR7 level and the prognosis of cancer patients.

Methods

Embase, Web of Science, and PubMed were systematically searched according to a defined search strategy up to June 11, 2018. Then, the required data were extracted from all qualified studies which were screened out based on the defined inclusion and exclusion criteria. Finally, the hazard ratios (HR) with 95% confidence intervals (CI) were used to evaluate the prognostic significance of CXCR7 in tumor patients.

Results

A total of 28 original research studies comprising 33 cohorts and 5685 patients were included in this meta-analysis. The results showed that CXCR7 overexpression was significantly related to worse overall survival (OS) (HR 1.72; 95% CI 1.49–1.99), disease-free survival (DFS) (HR 5.58; 95% CI 3.16–9.85), progression-free survival (PFS) (HR 2.83; 95% CI 1.66–4.85) and recurrence-free survival (RFS) (HR 1.58; 95% CI 1.34–1.88) in cancer patients. Furthermore, for certain types of cancer, significant associations between higher CXCR7 expression and worse OS of glioma (HR 1.77; 95% CI 1.43–2.19), breast cancer (HR 1.45; 95% CI 1.28–1.63), esophageal cancer (HR 2.72; 95% CI 1.11–6.66) and pancreatic cancer (HR 1.46; 95% CI 1.12–1.90) were found. However, for lung cancer and hepatocellular cancer, there was no significant relationship between CXCR7 expression level and OS, (HR 2.40; 95% CI 0.34–17.07) and (HR 1.37; 95% CI 0.84–2.24) respectively.

Conclusions

Increased CXCR7 level could predict poor prognosis of tumor patients and might be regarded as a novel prognostic biomarker for tumor patients.

Functions of the CXC ligand family in the pancreatic tumor microenvironment

Therapeutic resistance is the major contributor to the poor prognosis of and low survival from pancreatic cancer (PC). Cancer progression is a complex process reliant on interactions between the tumor and the tumor microenvironment (TME). Members of the CXCL family of chemokines are present in the pancreatic TME and seem to play a vital role in regulating PC progression. As pancreatic tumors interact with the TME and with PC stem cells (CSCs), determining the roles of specific members of the CXCL family is vital to the development of improved therapies. This review highlights the roles of selected CXCLs in the interactions between pancreatic tumor and its stroma, and in CSC phenotypes, which can be used to identify potential treatment targets.

Role of CXCR7 as a Common Predictor for Prognosis in Solid Tumors: a Meta-Analysis

Background: Accumulating evidence indicated that the CXC chemokine receptor (CXCR) 7 (CXCR7) was overexpressed in a variety of tumors. However, the value of the CXCR7 expression in predicting prognosis in solid tumors remains controversial. Therefore, we performed this meta-analysis to evaluate the correlation between CXCR7 expression and lymph node metastasis (LNM), tumor pathological grade and survival, including overall survival (OS), disease-free survival (DFS) and recurrence-free survival (RFS). Methods: Eligible studies were searched in PubMed, Web of Science, and PMC up to April 2018. A total of 27 studies were included in this meta-analysis. Odds ratio (OR), hazard ratio (HR) and 95 % confidence intervals (CI) were used as effect measures. Results: The meta-analysis showed that high expression of CXCR7 predicted a high risk of LNM (pooled OR = 2.22, 95%CI: 1.41-3.50), high tumor grade (pooled OR = 1.94, 95%CI: 1.20-3.13), poor OS (pooled HR = 1.66, 95%CI: 1.30-2.03), and poor DFS/RFS (pooled HR = 1.82, 95%CI: 1.21-2.43). Subgroup analysis showed that CXCR7 expression had a positive correlation with LNM in pan-adenocarcinoma subgroup (pooled OR = 3.73, 95%CI: 2.21-6.30), while no correlation was found in pan-squamous cancer subgroup (pooled OR = 1.29, 95%CI: 0.56-2.96). Subgroup analysis of tumor grade revealed that high expression of CXCR7 predicted high tumor grade both in pan-squamous cancer and pan-adenocarcinoma (pooled OR = 3.58, 95%CI: 1.39-9.22, pooled OR = 2.25, 95%CI: 1.20-4.20). As in OS group, we divided the data based on analysis method and it turned out that overexpressed CXCR7 predicted worse OS both in multivariate analysis (pooled HR =1.57, 95%CI: 1.12-2.01) and univariate analysis subgroup (pooled HR =1.86, 95%CI: 1.23-2.49). Conclusions: Our meta-analysis revealed that high expression of CXCR7 predicted unfavorable prognosis and may serve as potential targets of cancer therapy.

Upregulation of CXCR7 Is Associated with Poor Prognosis of Prostate Cancer

Background

Prostate cancer (PCa) is a prevalent cancer in males. CXCR7 exhibits oncogenic actions in various cancers. The aim of our study was to explore the clinical significance of CXCR7 in patients with PCa.

Material/Methods

QRT-PCR was used to detect the expression level of CXCR7 in PCa tissues. The relationship between CXCR7 expression and clinicopathologic parameters was evaluated by chi-square test. Kaplan-Meier survival curve was used for the survival analysis of patients. Cox regression analyses were performed to assess the potential of CXCR7 as a prognosis biomarker for PCa patients. We performed MTT and Transwell assays to determine the effect of CXCR7 on proliferative and migratory abilities of PCa cells, respectively.

Results

CXCR7 was upregulated in PCa tissues (P<0.05) and was correlated with PSA (P=0.023), differentiation (P=0.022), and lymph node metastasis (P=0.018). The results of MTT and Transwell assays demonstrated that inhibition of CXCR7 suppressed PCa cells growth and migration. Additionally, high CXCR7 level predicted poor overall survival (log rank test, P=0.019). CXCR7 was a valuable prognostic biomarker for PCa patients (HR=2.271, 95%CI=1.093–4.719, P=0.028).

Conclusions

CXCR7 is an oncogene in PCa that can promote aggressive progression of PCa through enhancing proliferation and migration of the tumor cells. CXCR7 is an independent biomarker for the prognosis of PCa.

Targeting Tumor Hypoxia Using Nanoparticle-engineered CXCR4-overexpressing Adipose-derived Stem Cells

Hypoxia, a hallmark of malignant tumors, often correlates with increasing tumor aggressiveness and poor treatment outcomes. Due to a lack of vasculature, effective drug delivery to hypoxic tumor regions remains challenging. Signaling through the chemokine SDF-1α and its receptor CXCR4 plays a critical role in the homing of stem cells to ischemia for potential use as drug-delivery vehicles. To harness this mechanism for targeting tumor hypoxia, we developed polymeric nanoparticle-induced CXCR4-overexpressing human adipose-derived stem cells (hADSCs). Using glioblastoma multiforme (GBM) as a model tumor, we evaluated the ability of CXCR4-overexpressing hADSCs to target tumor hypoxia in vitro using a 2D migration assay and a 3D collagen hydrogel model. Compared to untransfected hADSCs, CXCR4-overexpressing hADSCs showed enhanced migration in response to hypoxia and penetrated the hypoxic core within tumor spheres. When injected in the contralateral brain in a mouse intracranial GBM xenograft, CXCR4-overexpressing hADSCs exhibited long-range migration toward GBM and preferentially penetrated the hypoxic tumor core. Intravenous injection also led to effective targeting of tumor hypoxia in a subcutaneous tumor model. Together, these results validate polymeric nanoparticle-induced CXCR4-overexpressing hADSCs as a potent cellular vehicle for targeting tumor hypoxia, which may be broadly useful for enhancing drug delivery to various cancer types.

MicroRNA-126/stromal cell-derived factor 1/C-X-C chemokine receptor type 7 signaling pathway promotes post-stroke angiogenesis of endothelial progenitor cell transplantation

Stroke is the most common cause of mortality worldwide. Post-stroke angiogenesis is of great significance to the treatment of strokes. The aim of the present study was to investigate the mechanism underlying the angiogenesis-promoting effect of microRNA‑126 (miR‑126)‑associated signaling pathways using a stroke model in vivo and a cell migration model in vitro. Bone marrow‑derived endothelial progenitor cells (EPCs) were extracted and identified using a density gradient method. Reverse transcription‑quantitative polymerase chain reaction (RT‑qPCR) was performed to examine the expression levels of miR‑126 and C‑X‑C chemokine receptor type 7 (CXCR7). Target genes of miR‑126 were analyzed using TargetScan software version 7.1 (www.targetscan.org/). In addition, a reporter gene assay and RT‑qPCR were performed to determine the target genes of miR‑126. The effect of miR‑126 on cell migration was examined using a cell migration model in vitro and a middle cerebral artery occlusion model of mice was established in vivo. The miR‑126 antagomir‑treated EPCs were infused into stroke mice. Microvessel density, nerve function score and infarction volume were assessed. Flow cytometric analysis indicated that cluster of differentiation (CD)34, CD133 and vascular endothelial growth factor receptor 2 were partly expressed on the cell surface of bone marrow‑derived EPCs. In addition, the expression levels of Di‑acetylated‑low density lipoprotein and Ulex europaeus agglutinin 1 were positive. Stromal cell‑derived factor 1 (SDF-1) was identified as a target gene of miR‑126, which was confirmed by a reporter gene assay and RT‑qPCR. Cell migration examination demonstrated that the neutralizing antibody of CXCR7 blocked miR‑126 angomir‑induced migration of EPCs. Microvessel density increased, while nerve function score and infarction volume decreased following infusion of miR-126 angomir‑treated EPCs. Furthermore, miR‑126 angomir improved the efficacy of EPC treatment. Thus, miR‑126 improved the migration of EPCs via the miR‑126/SDF‑1/CXCR7 signaling pathway.

CXCR7 regulates breast tumor metastasis and angiogenesis in vivo and in vitro

The chemokine receptor CXCR7 is regarded as a scavenger receptor for CXCL12, and induces numerous key steps in tumor growth and metastasis. However, the exact molecular mechanism of CXCR7 regulation in breast tumor angiogenesis remains unknown. In the present study, the function of CXCR7 in breast tumors was investigated in vitro and in vivo. The breast cancer MDA-MB-231 cell line was used. Pharmacological inhibition of CXCR7 by CCX771 reduced breast tumor invasion, adhesion and metastasis. Furthermore, CXCR7 was essential for the tube formation of HUVECs in vitro, and for blood vessel formation in a Matrigel plug assay in vivo. In addition, vascular endothelial growth factor expression was also decreased in CCX771-treated MDA-MB-231 cells, indicating that CCX771 regulates tumor angiogenesis. The present results indicated that CXCR7 regulated breast cancer metastasis at multiple stages; additional understanding of CXCR7 in tumor environments may develop anti-metastatic therapy.

Targeting CXCR7 improves the efficacy of breast cancer patients with tamoxifen therapy

Chemokine (C-X-C motif) receptor 7 (CXCR7) has been established to be involved in breast cancer (BCa) progression. However, the role of CXCR7 in different subtype of BCa still remains unclear. Here we note that CXCR7 expression is significantly amplified in Luminal type BCa tissues as compared with Her2 and TNBC types through data-mining in TCGA datasets, and its protein level positively correlates with ERα expression by staining of human BCa tissue. Interestingly, alteration of CXCR7 expression in Luminal type BCa cells is able to modulate the expression of ERα through ubiquitination at post-translational level. Additionally, overexpression of CXCR7 in these cells greatly induces 4-OHT insensitivity in vitro and is associated with earlier recurrence in patients with tamoxifen therapy. Notably, silencing ERα expression potentially rescues the sensitivity of the above cells to 4-OHT, suggesting that elevated level of ERα is responsible for CXCR7-induced 4-OHT insensitivity in Luminal type BCa. Finally, mechanistic analyses show that the reduced BRCA1 (ubiquitin E3 ligase) and elevated OTUB1 (deubiquitinase) expression, which are regulated by CXCR7/ERK1/2 signaling pathway, are responsible for stabilizing ERα protein. In conclusion, our results suggest that targeting CXCR7 may serve as a potential therapeutic strategy for improving the efficacy of BCa patients with tamoxifen therapy.

The Oncogenic Role of COL23A1 in Clear Cell Renal Cell Carcinoma

Clear cell renal cell carcinoma (ccRCC) is the most common adult renal neoplasm and its incidence continues to increase. Collagen is the most abundant extracellular matrix protein in stroma, and contributes to the development and progression of ccRCC. We examined the human collagen type XXIII α1 chain (COL23A1) expression in ccRCC and the relationship between COL23A1 and patients' survival. We found COL23A1 mRNA was elevated in tumor compared with adjacent normal tissues, which was further validated by TCGA cohort. IHC results from 151 ccRCC cases suggested that high COL23A1 expression correlated with larger tumor size (P = 0.017) and advanced T stage (P = 0.011). The overall survival (OS) was shorter for ccRCC patients with high COL23A1 expression (P = 0.002). In multivariate analysis, high COL23A1 expression was an independent prognostic factor of OS (HR: 3.024, P = 0.017). Furthermore, COL23A1 knockdown repressed proliferation of ccRCC cell lines by blocking cell cycle progression. Cell adhesion and migration capacity was also downregulated by knockdown of COL23A1. Our data indicate that COL23A1 may be a novel prognostic indicator in ccRCC and might be a specific and accessible biomarker as well as a potential new target for clinical diagnosis of ccRCC.

Chemokine Receptors CXCR4 and CXCR7 are Associated with Tumor Aggressiveness and Prognosis in Extramammary Paget Disease

Chemokines are involved in many aspects of oncogenesis, including regulation of cancer cell growth, dissemination and host-tumor response. However, the potential of the chemokine receptors, CXCR4 and CXCR7, in serving as biomarkers in extramammary Paget's disease (EMPD) has been rarely examined. Expressions of CXCR4 and CXCR7 were evaluated in 92 EMPD specimens by immunohistochemistry. High expression of CXCR4 and CXCR7 were both correlated with regional lymph node metastasis and presence of lymphovascular invasion. High expression of CXCR7 also correlated with the depth of invasion. The prognostic value of these two chemokines were also investigated in progression-free survival (PFS) and cancer-specific survival (CSS). Both high expression of CXCR4 and CXCR7 were indicative of shorter PFS and CSS. In the combined prognostic model, concomitant high expression of CXCR4 and CXCR7 were suggestive of poor prognosis compared with the other two groups. In the multivariate analysis, depth of invasion, combined prognostic model and regional lymph node metastasis at diagnosis were the independent prognostic factors for EMPD patients for PFS, and the former two factors independently impacted CSS. Our results demonstrated that CXCR4 and CXCR7 can be used as prognostic biomarkers and prediction of aggressiveness of EMPD. Therapy targeting CXCR4 and CXCR7 may helpful to prevent EMPD progression and improve the prognosis of EMPD.

ACKR3 expression on diffuse large B cell lymphoma is required for tumor spreading and tissue infiltration

Diffuse large B cell lymphoma (DLBCL) is the most frequent lymphoma accounting for more than the 30% of the cases. Involvement of extranodal sites, such as bone marrow and central nervous system, is associated with poor prognosis. A contribution of the chemokine system in these processes is assumed as it is known as a critical regulator of the metastatic process in cancer. The atypical chemokine receptor 3 (ACKR3), which does not couple to G-proteins and does not mediate cell migration, acts as a scavenger for CXCL11 and CXCL12, interfering with the tumor homing CXCL12/CXCR4 axis. Here, functional expression of ACKR3 in DLBCL cells was necessary for colonization of the draining lymph node in an in vivo subcutaneous lymphoma model. Moreover, in a disseminated in vivo lymphoma model, ACKR3 expression was required for bone marrow and brain invasion and local tumor growth. The present data unveil ACKR3 as potential therapeutic target for the control of tumor dissemination in DLBCL.

Role of C-X-C chemokine ligand 12/C-X-C chemokine receptor 4 in the progression of hepatocellular carcinoma

The efficacy of the current non-surgical treatments for advanced hepatocellular carcinoma (HCC) remains limited and novel treatments are required to improve patient outcomes. The majority of HCCs develop from chronically damaged tissue that contains a high degree of inflammation and fibrosis, which promotes tumor progression and resistance to therapy. Understanding the interaction between stromal components and cancer cells (and the signaling pathways involved in this interaction) could aid the identification of novel therapeutic targets. Numerous studies have demonstrated a marked association between high C-X-C chemokine receptor 4 (CXCR4) expression and the invasiveness, progression and metastasis of HCC. The present review will investigate the different roles of CXCR4 in the progression of HCC and discuss possible future treatments. Through the C-X-C chemokine ligand 12 (CXCL12)/CXCR4 signaling pathway, ephrin A1 activation enhances the migration of endothelial progenitor cells to HCC to enable the neovascularization of tumors. There is an association between nuclear CXCR4 expression and the lymph node metastasis of HCC to distant areas. CXCR4 enhances cell migration in vitro and cell homing in vivo. CXCR4 levels are concentrated at the border of a tumor and in perivascular areas, inducing invasive behavior. The binding of CXCL12 to CXCR4 activates intracellular signaling pathways and induces crosstalk with transforming growth factor-β signaling, which enhances the migration of cancer cells. The CXCL12/CXCR4 axis also activates expression of matrix metalloproteinase 10, which further stimulates migration. CXCR4 is likely to crosstalk with the sonic hedgehog signaling pathway, contributing to tumor invasiveness and supporting the cancer stem-cell population; as a result, CXCR4 can be regarded as a cancer stem-cell marker. CXCR4 influences interstitial fluid flow-induced invasion. CXCR4 expression and HCC cell migration are promoted by α-fetoprotein, which activates AKT/mechanistic target of rapamycin signaling. CXCR4 also has the potential to affect sorafenib treatment for HCC. Targeting the CXCL12/CXCR4 signaling pathway may, therefore, be a promising strategy in HCC treatment.

A meta-analysis of CXCL12 expression for cancer prognosis

Background:

CXCL12 (SDF1) is reported to promote cancer progression in several preclinical models and this is corroborated by the analysis of human tissue specimens. However, the relationship between CXCL12 expression and cancer survival has not been systematically assessed.

Methods:

We conducted a systematic review and meta-analysis of studies that evaluated the association between CXCL12 expression and cancer survival.

Results:

Thirty-eight studies inclusive of 5807 patients were included in the analysis of overall, recurrence-free or cancer-specific survival, the majority of which were retrospective. The pooled hazard ratios (HRs) for overall and recurrence-free survival in patients with high CXCL12 expression were 1.39 (95% CI: 1.17–1.65, P=0.0002) and 1.12 (95% CI: 0.82–1.53, P=0.48) respectively, but with significant heterogeneity between studies. On subgroup analysis by cancer type, high CXCL12 expression was associated with reduced overall survival in patients with oesophagogastric (HR 2.08; 95% CI: 1.31–3.33, P=0.002), pancreatic (HR 1.54; 95% CI: 1.21–1.97, P=0.0005) and lung cancer (HR 1.37; 95% CI: 1.08–1.75, P=0.01), whereas in breast cancer patients high CXCL12 expression conferred an overall survival advantage (HR 0.5; 95% CI: 0.38–0.66, P<0.00001).

Conclusions:

Determination of CXCL12 expression has the potential to be of use as a cancer biomarker and adds prognostic information in various cancer types. Prospective or prospective–retrospective analyses of CXCL12 expression in clearly defined cancer cohorts are now required to advance our understanding of the relationship between CXCL12 expression and cancer outcome.

神经营养因子和趋化因子与胰腺癌神经浸润的研究进展

胰腺癌癌细胞浸润神经组织, 沿神经或进入神经束膜内沿束膜间隙浸润生长, 即发生神经浸润(perineural invasion, PNI). PNI是特殊的肿瘤转移通路, 在胰腺癌中的发生率极高, 为胰腺癌的重要生物学特性之一, 被认为是导致胰腺癌手术后高复发率和胰腺癌相关疼痛的最主要原因之一, 与患者不良预后和低存活率密切相关. PNI发生的机制十分复杂, 涉及多种生物分子和信号途径. 神经营养因子和趋化因子参与相关信号通路, 促进癌细胞神经交互作用, 导致胰腺癌PNI发生, 在胰腺癌PNI中扮演重要角色. 本文将神经营养因子家族和趋化因子与胰腺癌PNI的研究进展作一综述.

CCL21/CCR7 interaction promotes cellular migration and invasion via modulation of the MEK/ERK1/2 signaling pathway and correlates with lymphatic metastatic spread and poor prognosis in urinary bladder cancer

Lymph node metastasis in patients with urinary bladder cancer (UBC) is always associated with poor prognosis and is the determinant for tumor staging and the development of treatment regimens; however, its underlying mechanisms remain to be studied. Immunohistochemical staining of tumor sections from 62 UBC patients was performed using CCR7, D2-40 and CD34 antibodies. We showed that increased CCR7 expression was significantly associated with positive lymph node status (P=0.008), pT3-T4 tumor stage (P=0.015), tumor grade (P=0.010) and worse overall survival (OS, P<0.001) and that both CCR7 expression and lymph node metastasis were independent prognostic factors for OS (P=0.031 and P=0.001, respectively) based on multivariate analysis. We found that there was a significant association between MLVD and lymph node status (P=0.006), but this relation was not observed for MVD. Furthermore, we showed that increased CCR7 expression correlated significantly with higher MLVD (P=0.014) and MVD (P=0.002). Wound-healing and Matrigel Transwell assays indicated that activation of CCR7 with CCL21 significantly enhanced the invasion and migration abilities of UM-UC-3 cells, and this enhanced effect was significantly abrogated by CCR7 knockdown using siRNA. Western blot analysis revealed that the phospho-ERK1/2 level was markedly increased when UM-UC-3 cells were treated with CCL21 and significantly decreased when the CCR7 gene was silenced. MEK/ERK1/2 inhibition with PD98059 significantly suppressed the migration and invasion abilities of UM-UC-3 cells and also significantly abrogated the effects of CCL21/CCR7 on cell migration and invasion. Based on these results, we conclude that activation of the CCL21/CCR7 chemoaxis promotes lymph node metastasis of UBC in at least two ways. Firstly, although CCR7 is a promoting factor that induces both lymphangiogenesis and angiogenesis, it may promote lymph node metastasis through its lymphangiogenic effect rather than through its angiogenic effect. Secondly, the CCL21/CCR7 chemoaxis promotes the migration and invasion of UBC cells via the MEK/ERK1/2 signaling pathway rather than the PI3K/AKT pathway.