CXCR4 expression predicts patient outcome and recurrence patterns after hepatic resection for colorectal liver metastases

Exploring Predictive and Prognostic Biomarkers in Colorectal Cancer: A Comprehensive Review

Colorectal cancer (CRC) remains the second leading cause of cancer-related mortality worldwide. While immune checkpoint inhibitors have significantly improved patient outcomes, their effectiveness is mostly limited to tumors with microsatellite instability (MSI-H/dMMR) or an increased tumor mutational burden, which comprise 10% of cases. Advancing personalized medicine in CRC hinges on identifying predictive biomarkers to guide treatment decisions. This comprehensive review examines established tissue markers such as KRAS and HER2, highlighting their roles in resistance to anti-EGFR agents and discussing advances in targeted therapies for these markers. Additionally, this review summarizes encouraging data on promising therapeutic targets and highlights the clinical utility of liquid biopsies. By synthesizing current evidence and identifying knowledge gaps, this review provides clinicians and researchers with a contemporary understanding of the biomarker landscape in CRC. Finally, the review examines future directions and challenges in translating promising biomarkers into clinical practice, with the goal of enhancing personalized medicine approaches for colorectal cancer patients.

Colorectal Cancer: The Contribution of CXCL12 and Its Receptors CXCR4 and CXCR7

Colorectal cancer is one of the most common cancers, and diagnosis at late metastatic stages is the main cause of death related to this cancer. This progression to metastasis is complex and involves different molecules such as the chemokine CXCL12 and its two receptors CXCR4 and CXCR7. The high expression of receptors in CRC is often associated with a poor prognosis and aggressiveness of the tumor. The interaction of CXCL12 and its receptors activates signaling pathways that induce chemotaxis, proliferation, migration, and cell invasion. To this end, receptor inhibitors were developed, and their use in preclinical and clinical studies is ongoing. This review provides an overview of studies involving CXCR4 and CXCR7 in CRC with an update on their targeting in anti-cancer therapies.

Prognostic Significance of CXCR4 in Colorectal Cancer: An Updated Meta-Analysis and Critical Appraisal

Simple Summary

C-X-C chemokine receptor type 4 (CXCR4), a G-protein-coupled receptor, has been demonstrated to stimulate proliferation and invasiveness of many different tumors, including colorectal cancer. Through in vitro evidence, overexpression of CXCR4 has been identified as a negative prognostic factor in colorectal cancer. The identification of prognostic biomarkers can improve the prediction of disease evolution and disease characterization, and guide treatment efforts. This systematic review with a meta-analysis was conducted to pool hazard ratios from prognostic studies on CXCR4, provide an updated estimate of prognostic power of CXCR4, and analyze modalities of evaluating and reporting CXCR4 expression.

Abstract

Background: This study was conducted to provide an updated estimate of the prognostic power of C-X-C chemokine receptor type 4 (CXCR4) in colorectal cancer (CRC), and analyze modalities of evaluating and reporting its expression. Methods: A systematic review with meta-analysis was performed and described according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement. Studies were identified through PubMed and Google Scholar. The pooled hazard ratios (HRs) for overall survival (OS) or progression-free survival (PFS) with 95% confidence interval (CI) were estimated with the random-effect model. Results: Sixteen studies were selected covering a period from 2005 to 2020. An immunohistochemical evaluation of CXCR4 was performed in all studies. Only in three studies assessment of mRNA through RT–PCR was correlated with prognosis; in the remaining studies, the authors identified prognostic categories based on immunohistochemical expression. In pooled analyses, significant associations were found between positive or high or strong expression of CXCR4 and T stage ≥3 (P = 0.0001), and positive or high or strong expression of CXCR4 and left side primary tumor localization (P = 0.0186). The pooled HR for OS was 2.09 (95% CI: 1.30–2.88) in favor of high CXCR4 expression; for PFS, it was 1.42 (95% CI: 1.13–1.71) in favor of high CXCR4 expression. Conclusion: High CXCR4 expression is clearly associated with increased risk of death and progression in CRC. However, strong methodologic heterogeneity in CXCR4 assessment hinders direct translation into clinical practice; thus, a consensus to streamline detection and scoring of CXCR4 expression in CRC is indicated.

Landscape of cell heterogeneity and evolutionary trajectory in ulcerative colitis-associated colon cancer revealed by single-cell RNA sequencing

Objective

The goal of this study was to get preliminary insight on the intra-tumor heterogeneity in colitis-associated cancer (CAC) and to reveal a potential evolutionary trajectory from ulcerative colitis (UC) to CAC at the single-cell level.

Methods

Fresh samples of tumor tissues and adjacent UC tissues from a CAC patient with pT3N1M0 stage cancer were examined by single-cell RNA sequencing (scRNA-seq). Data from The Cancer Genome Atlas (TCGA) and The Human Protein Atlas were used to confirm the different expression levels in normal and tumor tissues and to determine their relationships with patient prognosis.

Results

Ultimately, 4,777 single-cell transcriptomes (1,220 genes per cell) were examined, of which 2,250 (47%) and 2,527 (53%) originated from tumor and adjacent UC tissues, respectively. We defined the composition of cancer-associated stromal cells and identified six cell clusters, including myeloid, T and B cells, fibroblasts, endothelial and epithelial cells. Notable pathways and transcription factors involved in these cell clusters were analyzed and described. Moreover, the precise cellular composition and developmental trajectory from UC to UC-associated colon cancer were graphed, and it was predicted that CD74, CLCA1, and DPEP1 played a potential role in disease progression.

Conclusions

scRNA-seq technology revealed intra-tumor cell heterogeneity in UC-associated colon cancer, and might provide a promising direction to identify novel potential therapeutic targets in the evolution from UC to CAC.

Tumor inhibition or tumor promotion? The duplicity of CXCR3 in cancer

Tumor tissue includes cancer cells and normal stromal cells such as vascular endothelial cells, connective tissue cells (cancer associated fibroblast, mesenchymal stem cell), and immune cells (tumor-infiltrating lymphocytes or TIL, dendritic cells, eosinophils, basophils, mast cells, tumor-associated macrophages or TAM, myeloid-derived suppressor cells or MDSC). Anti-tumor activity is mainly mediated by infiltration of NK cells, Th1 and CD8⁺ T cells, and correlates with expression of NK cell and T cell attracting chemokines. Nevertheless, cancer cells hijack tissue homeostasis through secretion of cytokines and chemokines that mediate not only the induction of an inflamed status that supports cancer cell survival and growth, but also the recruitment and/or activation of immune suppressive cells. CXCL9, CXCL10, and CXCL11 are known for their tumor-inhibiting properties, but their overexpression in several hematologic and solid tumors correlates with disease severity, suggesting a role in tumor promotion. The dichotomous nature of CXCR3 ligands activity mainly depends on several molecular mechanisms induced by cancer cells themselves able to divert immune responses and to alter the whole local environment. A deep understanding of the nature of such phenomenon may provide a rationale to build up a CXCR3/ligand axis targeting strategy. In this review, we will discuss the role of CXCR3 in cancer progression and in regulation of anti-tumor immune response and immunotherapy.

High CXCR4 expression in adenoid cystic carcinoma of the head and neck is associated with increased risk of locoregional recurrence

AIM

Treatment options for head and neck adenoid cystic carcinoma (AdCC) are limited in advanced disease. Chemokine receptor type 4 (CXCR4) is present in various tumour types, including AdCC. Upregulation is associated with tumour recurrence and metastasis. New CXCR4-specific diagnostic and therapeutic target agents have recently been available. This study aimed to analyse CXCR4 expression in a cohort of primary head and neck AdCC.

METHODS

After histopathological revision, tumour tissues of 73 consecutive patients with AdCC over 1990-2016 were sampled on a tissue microarray. Slides were immunohistochemically stained for CXCR4 and semiquantitatively scored. Associations between protein expression and cliniopathological parameters were tested. HRs were calculated using a Cox proportional hazard model.

RESULTS

Sixty-six tumours could be analysed. CXCR4 expression was present in 81% of the tumours with a median of 29% (IQR 1-70) positive cells. Expression was univariately correlated to perineural growth (Spearman ρ .26, p=0.04) and bone invasion (Spearman ρ .32, p=0.01), but not with tumour grade.CXCR4 expression in the primary tumour was significantly higher in tumours that recurred as compared with those that did not recur (median 60%, IQR 33-72 vs 12%, IQR 1-70, Kruskal-Wallis p=0.01). After dichotomisation, >25% of CXCR4 expressions proved an independent prognosticator for a reduced recurrence-free survival (RFS) (HR 7.2, 95% CI 1.5 to 72.4, p=0.04).

CONCLUSION

CXCR4 is expressed in the majority of primary AdCCs and independently correlated to worse RFS, suggesting CXCR4 as a target for imaging and therapy purposes in patients with advanced AdCC.

CXCR4/TGF-β1 mediated hepatic stellate cells differentiation into carcinoma-associated fibroblasts and promoted liver metastasis of colon cancer

Background: Liver metastasis of colon cancer is strongly affected by the tumor microenvironment (TME), with interactions between tumor cells and cancer-associated fibroblasts (CAFs) in particular. TGF-β is well known for its ability to mediate the CAF phenotype, and CXCR4 expression is closely correlated to poor prognosis in CRC. The relationship between these two signaling pathways remains to be delineated in liver metastasis of colon cancer.Methods: Immunohistochemistry was employed to investigate CXCR4 expression in 45 human specimens of primary colorectal cancer (CRC) and liver metastasis. The functions of SDF-1 released by hepatic stellate cells (HSCs) on CXCR4 and TGF-β1 in CRC cells were investigated in vitro. The effects of CRC on HSCs differentiation into CAFs were confirmed using co-culture technology and expression analysis of CAFs markers by qPCR, western blot and immunofluorescence. The involvement of CXCR4 and TGF-β1 was verified with addition of CXCR4 inhibitor AMD3100 and TGF-β1 inhibitor cyclophosphamide (Cy) both in vitro and in vivo.Results: There were more CXCR4-positive cells at the liver metastatic tissues compared to the primary sites. CRC cells activated and transformed HSCs to CAFs after co-cultivating with HSCs. Activated HSCs stimulated TGF-β1 secretion from CRC cells after co-culture with CRC cells in vitro. Moreover, the expression of CAFs markers was increasing in the activated HSCs. In a mouse hepatic metastasis model, treated with AMD3100 or Cy blocked the metastatic potential of HCT116 cells and the hepatic CAFs differentiation.Conclusions: These results indicated that CXCR4/TGF-β1 axis plays an important role in CRC liver metastasis through mediating HSCs differentiation into CAFs, providing preclinical evidences that blockade of the axis might be beneficial for anti-metastasis therapy in CRC.

Chemokines – role in inflammatory and cancer diseases

Over 50 human chemokines are known at present; the number of the newly discovered compounds from this group still grows. These proteins of low molecular weight, belonging to the family of cytokines with chemotactic properties. Chemokines participate in the physiological and pathological processes of the organism. Recent papers show their role in the processes of embryogenesis, organogenesis, allergies, wound healing, angiogenesis and apoptosis, the course of viral and bacterial infections, autoimmune diseases and cancerogenesis. Chemokines play crucial role in activation and migration of immune cells. Being a key player in chronic inflammation, chemokines may interfere the processes of cellular differentiation and contribute to loss of control over proliferation. Coexistence of inflammatory and cancerogenesis processes, impact of chemokines on cells associated with the tumor and stromal cells, mechanisms of immunological escape is considered to be a current scientific issue. Newly discovered functions of chemokines may reveal their new roles and create the new therapeutic perspectives. It is important to understand the relationship between the structure and function of chemokine receptors, the regulation of their signaling pathways and the genetic and epigenetic mechanisms that regulate the expression of chemokines and their receptors. This article presents the current state of knowledge regarding the construction and classification of chemokines and summarizes the most prominent roles of chemokines. Chemokines are still the subject of many scientific studies, new functions are being discovered. It gives an opportunity to limit the development of many dangerous diseases.

CXCR4 as a prognostic biomarker in gastrointestinal cancer: a meta-analysis

Background: CXCR4 is a member of the C-X-C chemokine receptor family, which is associated with multiple types of cancer. Although it has been widely reported, the prognostic value of CXCR4 expression in gastrointestinal (GI) cancer remains controversial. Methods: A meta-analysis was conducted to investigate the relationship between CXCR4 and prognosis of patients with GI cancer. Subgroup analysis was also performed according to tumour subtypes and heterogeneity test. Results: A total of 24 studies including 3637 cases suggested that overexpression of CXCR4 is significantly associated with overall survival (OS) for patients with GI cancer (HR = 1.71, 95% CI = 1.45-2.03, p = 0.000). Subgroup analysis also indicated that high CXCR4 expression in oesophagus, gastric and colorectal cancer all predicted a worse prognosis (HR = 1.52, 95% CI = 1.26-1.84, p = 0.001 for oesophagus cancer; HR = 1.59, 95% CI = 1.10-2.30, p = 0.015 for gastric cancer; HR = 2.21, 95% CI = 1.56-3.14, p = 0.000 for colorectal cancer). Conclusions: CXCR4 may serve as a prognostic indicator in GI cancer patients.

CXCR4 in human osteosarcoma malignant progression. The response of osteosarcoma cell lines to the fully human CXCR4 antibody MDX1338

Osteosarcoma (OS) is the most frequent primary malignant tumour of bone and metastases occur in 30% of cases, the 5-year survival rate is 25–30%.

Although pre- and post-operative chemotherapy has improved prognosis in osteosarcoma (OS), high toxicity and natural and acquired drug-resistance are the first cause of treatment failure. The identification of new predictive and therapeutic biomarkers may increase drug sensitivity and better control localized and metastatic disease. By the evidence that CXCR4 receptor by binding its ligand CXCL12 activates downstream critical endpoints for tumour malignancy, we first studied human OS progression correlating CXCR4 expression in OS biopsy with patient clinical data. By Real-time PCR and immunoistochemistry we found that high levels of CXCR4 gene and protein expression significantly correlated with OS progression, emphasizing the role of CXCR4/CXCL12 axis in tumour prognosis. This was supported by univariate analyses that showed a higher probability of local and/or systemic relapse in OS patients with a high CXCR4 gene expression and a significant increase of metastasis risk associated with an increasing score of CXCR4 protein staining intensity. Secondarily, to study the role of CXCR4 as a target for new therapeutic strategies, we evaluated the response of OS cells to the fully human CXCR4 antibody, MDX1338. In the study we also included AMD3100, the most studied CXCR4 antagonist.

In CXCR4-positive OS cells cultured in CXCL12-rich BM-MCS-CM (bone marrow-derived mesenchymal stem conditioned medium), a decrease of cell proliferation up to 30%–40% of control was seen after drug exposure. However, an increase of apoptosis was seen in p53-positive U2OS and 143B after CXCR4 inhibitor incubation, while no changes were seen in treated SAOS-2 cells which also present a different labeling profile. The role of p53 in apoptotic response to CXCR4 inhibitors was confirmed by p53 silencing in U2OS cell line. Our data suggest that the response to anti-CXCR4 agents could be influenced by the genetic background and labeling profile which induces a different cross-talk between tumour cells and environment. The delay in cell cycle progression associated with increased apoptosis could sensitize p53-positive cells to conventional therapy and in vivo preclinical experiments are on going with the aim to suggest new combined target therapies in human OS.

Systematic Review of the Prognostic Role of the Immune System After Surgery of Colorectal Liver Metastases

Background: The current prognostication of patient survival after surgery for colorectal liver metastases is based on clinical characteristics, but low accuracy makes it difficult to guide treatment for the individual patient. Rapidly evolving technologies have led to the expectation that biomarkers will be able to outperform the current clinical scoring systems and provide more effective personalised treatment. Two main topics prevail in cancer treatment, namely the role of the immune system and the prediction and prognostication by application of high-throughput methodology. The aim of this review is to examine the evidence for prognostic immunological and molecular markers studied in tumour tissue obtained at surgical resection for colorectal liver metastases.

Methods: First we analysed immunophenotypical protein markers, that are mainly studied by immunohistochemistry. Second, we review molecular markers by analysing high-throughput studies on tumour mRNA and microRNA expression.

Results: CD3, CD4, and CD8 are the most frequently studied protein markers. High intra-tumoural CD3+ T cell infiltration and low CXCR4 expression have the best association with favourable patient survival. Studies that analysed microRNA or mRNA expression data showed very little overlap in prognostic genes.

Conclusions: Patient prognostication after surgery for colorectal liver metastases by analysing the immune system remains difficult. Current data are based on diverse and heterogeneous patient populations which prohibits drawing firm conclusions.

The Diagnostic Value of Chemokine/Chemokine Receptor Pairs in Hepatocellular Carcinoma and Colorectal Liver Metastasis

Chemokines and their receptors have been proposed to play important roles in tumor progression and metastasis. To investigate their roles in the progression of primary and metastatic malignant liver tumors and their prognosis, we compared expression profiles of CXCL12/CXCR4, CCL20/CCR6, and CCL21/CCR7 in hepatocellular carcinoma (HCC) and colorectal liver metastases (CRLM). Immunohistochemistry was used to analyze the expression levels of the chemokine/chemokine receptor pairs in 29 HCC and 11 CRLM specimens and adjacent non-cancerous tissues, and correlations with clinicopathological variables and overall survival were determined. CCL20/CCR6 expression was higher in HCC than in adjacent non-cancerous tissues. High CCR6 expression in HCC was negatively associated with 5-year survival rate and was an independent prognostic factor for overall survival of HCC patients, whereas differences were not observed between CRLM and adjacent tissues. Furthermore, significantly higher expression of CCL21/CCR7 was found in CRLM than in HCC. In summary, the CCL20/CCR6 axis was elevated in HCC but not in CRLM, whereas the CCL21/CCR7 axis was elevated in CRLM but not in HCC.

CXC family of chemokines as prognostic or predictive biomarkers and possible drug targets in colorectal cancer

Colorectal cancer (CRC) is the third most common cancer in men and the second most common cancer in women, worldwide. In the early stages of the disease, biomarkers predicting early relapse would improve survival rates. In metastatic patients, the use of predictive biomarkers could potentially result in more personalized treatments and better outcomes. The CXC family of chemokines (CXCL1 to 17) are small (8 to 10 kDa) secreted proteins that attract neutrophils and lymphocytes. These chemokines signal through chemokine receptors (CXCR) 1 to 8. Several studies have reported that these chemokines and receptors have a role in either the promotion or inhibition of cancer, depending on their capacity to suppress or stimulate the action of the immune system, respectively. In general terms, activation of the CXCR1/CXCR2 pathway or the CXCR4/CXCR7 pathway is associated with tumor aggressiveness and poor prognosis; therefore, the specific inhibition of these receptors is a possible therapeutic strategy. On the other hand, the lesser known CXCR3 and CXCR5 axes are generally considered to be tumor suppressor signaling pathways, and their stimulation has been suggested as a way to fight cancer. These pathways have been studied in tumor tissues (using immunohistochemistry or measuring mRNA levels) or serum [using enzyme-linked immuno sorbent assay (ELISA) or multiplexing techniques], among other sample types. Common variants in genes encoding for the CXC chemokines have also been investigated as possible biomarkers of the disease. This review summarizes the most recent findings on the role of CXC chemokines and their receptors in CRC and discusses their possible value as prognostic or predictive biomarkers as well as the possibility of targeting them as a therapeutic strategy.

Development and validation of an immunity-related classifier of nine chemokines for predicting recurrence in stage I-III patients with colorectal cancer after operation

Introduction

Chemokines are closely related with tumor immunity, progression, and metastasis. We aimed to construct a multi-RNA classifier of chemokine family genes for predicting tumor recurrence in stage I-III patients with colorectal cancer (CRC) after operation.

Patients and methods

By analyzing microarray data, the Cox regression analysis was conducted to determine survival-related chemokine family genes and develop a multi-RNA classifier in the training set. The prognostic value of this multi-RNA classifier was further validated in the internal validation and external independent sets. Receiver operating characteristic curves were used to compare the prediction ability of the combined model of this multi-RNA classifier and stage, and this multi-RNA classifier and stage alone.

Results

Nine survival-related chemokines were identified in the training set. We identified a nine-chemokine classifier and classified the patients as high-risk or low-risk. Compared with CRC patients with high-risk scores, CRC patients with low-risk scores had longer disease-free survival in the training (HR=2.353, 95% CI=1.480-3.742, P<0.001), internal validation (HR=2.389, 95% CI=1.428-3.996, P<0.001), and external independent (HR=3.244, 95% CI=1.813-5.807, P<0.001) sets. This nine-chemokine classifier was an independent prognostic factor in these datasets (P<0.05). The combined model of this nine-chemokine classifier and tumor stage may tend to have higher accuracy than stage alone in the training (area under curve 0.727 vs 0.626, P<0.01), internal validation (0.668 vs 0.584, P=0.03), and external independent (0.704 vs 0.678, P>0.05) sets. This nine-chemokine classifier may only be applied in Marisa's C2, C5, and C6 subtypes patients.

Conclusion

Our nine-chemokine classifier is a reliable prognostic tool for some specific biological subtypes of CRC patients. It might contribute to guide the personalized treatment for high-risk patients.

CXCR4-CXCL12-CXCR7, TLR2-TLR4, and PD-1/PD-L1 in colorectal cancer liver metastases from neoadjuvant-treated patients

A neoadjuvant clinical trial was previously conducted in patients with resectable colorectal cancer liver metastases (CRLM). At a median follow up of 28 months, 20/33 patients were dead of disease, 8 were alive with disease and 5 were alive with no evidence of disease. To shed further insight into biological features accounting for different outcomes, the expression of CXCR4-CXCL12-CXCR7, TLR2-TLR4, and the programmed death receptor-1 (PD-1)/programmed death-1 ligand (PD-L1) was evaluated in excised liver metastases. Expression profiles were assessed through qPCR in metastatic and unaffected liver tissue of 33 CRLM neoadjuvant-treated patients. CXCR4 and CXCR7, TLR2/TLR4, and PD-1/PD-L1 mRNA were significantly overexpressed in metastatic compared to unaffected liver tissues. CXCR4 protein was negative/low in 10/31, and high in 21/31, CXCR7 was negative/low in 16/31 and high in 15/31, CXCL12 was negative/low in 14/31 and high in 17/31 CRLM. PD-1 was negative in 19/30 and positive in 11/30, PD-L1 was negative/low in 24/30 and high in 6/30 CRLM. Stromal PD-L1 expression, affected the progression-free survival (PFS) in the CRLM population. Patients overexpressing CXCR4 experienced a worse PFS and cancer specific survival (CSS) (p = 0.001 and p = 0.0008); in these patients, KRAS mutation identified a subgroup with a significantly worse CSS (p < 0.01). Thus, CXCR4 and PD-L1 expression discriminate patients with the worse PFS within the CRLM evaluated patients. Within the CXCR4 high expressing patients carrying Mut-KRAS in CRLM identifies the worst prognostic group. Thus, CXCR4 targeting plus anti-PD-1 therapy should be explored to improve the prognosis of Mut-KRAS-high CXCR4-CRLMs.

The prognostic role of serum C-X-C chemokine receptor type 4 in patients with metastatic or recurrent colorectal cancer

BACKGROUND

C-X-C chemokine receptor type 4 (CXCR4) is involved in tumor progression including angiogenesis, metastasis, and survival. However, whether serum CXCR4 levels in metastatic or recurrent colorectal cancer have a prognostic role, have not been evaluated.

METHODS

We analyzed serum samples from 55 patients with advanced colorectal cancer diagnosed between March 2008 and July 2011. Serum CXCR4 levels were quantified by a commercially available enzyme-linked immunosorbent assay (ELISA) kit.

RESULTS

The median age of the patients was 62 years, and all patients received systemic chemotherapy of two or more lines. The median serum CXCR4 level was 283.47 pg/mL (range: 77.48-846.52). Patients with two or more metastatic sites, liver metastasis, or higher CA 19-9 level (>37 IU/mL) showed significantly higher levels of serum CXCR4 than patients without. The median overall survival (OS) of all patients was 19.53 months. OS was significantly longer in patients with lower CXCR4 levels (≤240.45 pg/mL) compared with those having higher CXCR4 levels (>240.45 pg/mL) (median OS: 26.50 vs 17.03 months, P=0.046). Univariate analysis showed that liver metastasis, no palliative surgery, and higher levels of CXCR4 (>240.45 pg/mL) had a significantly poor prognostic value with regard to OS (P<0.05).

CONCLUSION

Serum CXCR4 level was positively correlated with metastatic sites, liver metastasis, or higher CA 19-9 level. Also, there was a significant difference in OS according to the level of CXCR4 expression. These findings suggest that serum CXCR4 levels may be a useful surrogate marker of clinical outcome in metastatic or recurrent colorectal cancer.

The Role of Chemokines in Promoting Colorectal Cancer Invasion/Metastasis

Colorectal cancer (CRC) is one of the leading causes of cancer-related death worldwide. Although most of the primary CRC can be removed by surgical resection, advanced tumors sometimes show recurrences in distant organs such as the liver, lung, lymph node, bone or peritoneum even after complete resection of the primary tumors. In these advanced and metastatic CRC, it is the tumor-stroma interaction in the tumor microenvironment that often promotes cancer invasion and/or metastasis through chemokine signaling. The tumor microenvironment contains numerous host cells that may suppress or promote cancer aggressiveness. Several types of host-derived myeloid cells reside in the tumor microenvironment, and the recruitment of them is under the control of chemokine signaling. In this review, we focus on the functions of chemokine signaling that may affect tumor immunity by recruiting several types of bone marrow-derived cells (BMDC) to the tumor microenvironment of CRC.

Targeting CXCR4 by a selective peptide antagonist modulates tumor microenvironment and microglia reactivity in a human glioblastoma model

BACKGROUND

The CXCL12/CXCR4 pathway regulates tumor cell proliferation, metastasis, angiogenesis and the tumor-microenvironment cross-talk in several solid tumors, including glioblastoma (GBM), the most common and fatal brain cancer. In the present study, we evaluated the effects of peptide R, a new specific CXCR4 antagonist that we recently developed by a ligand-based approach, in an in vitro and in vivo model of GBM. The well-characterized CXCR4 antagonist Plerixafor was also included in the study.

METHODS

The effects of peptide R on CXCR4 expression, cell survival and migration were assessed on the human glioblastoma cell line U87MG exposed to CXCL12, by immunofluorescence and western blotting, MTT assay, flow cytometry and transwell chamber migration assay. Peptide R was then tested in vivo, by using U87MG intracranial xenografts in CD1 nude mice. Peptide R was administered for 23 days since cell implantation and tumor volume was assessed by magnetic resonance imaging (MRI) at 4.7 T. Glioma associated microglia/macrophage (GAMs) polarization (anti-tumor M1 versus pro-tumor M2 phenotypes) and expressions of vascular endothelial growth factor (VEGF) and CD31 were assessed by immunohistochemistry and immunofluorescence.

RESULTS

We found that peptide R impairs the metabolic activity and cell proliferation of human U87MG cells and stably reduces CXCR4 expression and cell migration in response to CXCL12 in vitro. In the orthotopic U87MG model, peptide R reduced tumor cellularity, promoted M1 features of GAMs and astrogliosis, and hindered intra-tumor vasculature.

CONCLUSIONS

Our findings suggest that targeting CXCR4 by peptide R might represent a novel therapeutic approach against GBM, and contribute to the rationale to further explore in more complex pre-clinical settings the therapeutic potential of peptide R, alone or in combination with standard therapies of GBM.

CXCR4 over-expression and survival in cancer: a system review and meta-analysis

C-X-C chemokine receptor 4 (CXCR4) is frequently over-expressed in various types of cancer; many agents against CXCR4 are in clinical development currently despite variable data for the prognostic impact of CXCR4 expression. Here eighty-five studies with a total of 11,032 subjects were included to explore the association between CXCR4 and progression-free survival (PFS) or overall survival (OS) in subjects with cancer. Pooled analysis shows that CXCR4 over-expression is significantly associated with poorer PFS (HR 2.04; 95% CI, 1.72-2.42) and OS (HR=1.94; 95% CI, 1.71-2.20) irrespective of cancer types. Subgroup analysis indicates significant association between CXCR4 and shorter PFS in hematological malignancy, breast cancer, colorectal cancer, esophageal cancer, renal cancer, gynecologic cancer, pancreatic cancer and liver cancer; the prognostic effects remained consistent across age, risk of bias, levels of adjustment, median follow-up period, geographical area, detection methods, publication year and size of studies. CXCR4 over-expression predicts unfavorable OS in hematological malignancy, breast cancer, colorectal cancer, esophageal cancer, head and neck cancer, renal cancer, lung cancer, gynecologic cancer, liver cancer, prostate cancer and gallbladder cancer; these effects were independence of age, levels of adjustment, publication year, detection methods and follow-up period. In conclusion, CXCR4 over-expression is associated with poor prognosis in cancer.

Surgical management of hepatic metastases of colorectal cancer

For the 20% of patients with resectable colorectal liver metastases (CRLM), hepatic resection is safe, effective and potentially curative. Factors related to the primary and metastatic tumors individually and in clinical risk-scoring schemes are the best prognostic factors, although it is difficult to define patient groups with resectable, liver-limited CRLM that should be excluded from surgery. Systemic chemotherapy for metastatic colorectal cancer has improved but does not improve overall survival as adjuvant therapy after resection. Conversion to complete resection with systemic and/or hepatic arterial infusion chemotherapy is an appropriate goal for patients with unresectable CRLM.

A meta-analysis for C-X-C chemokine receptor type 4 as a prognostic marker and potential drug target in hepatocellular carcinoma

Chemokines (CKs), small proinflammatory chemoattractant cytokines that bind to specific G-protein coupled seven-span transmembrane receptors, are major regulators of cell trafficking and adhesion. C-X-C chemokine receptor type 4 (CXCR4) has gained tremendous attention over the last decade, since it was found to be upregulated in a wide variety of cancer types, including hepatocellular carcinoma (HCC). The clinical relevance of expression of CXCR4 in HCC remains controversial; our aim was to identify the precise relationship of CXCR4 to prognosis and clinicopathological features. We searched the database from MEDLINE, PubMed, Web of Science, Scopus and Embase and then conducted a meta-analysis from publications met the inclusion criteria for the qualitative study. Our data showed that 1) CXCR4 is overexpressed in HCC tissues but not in normal hepatic tissue, OR =84.26, 95% confidence interval (CI) =11.86–598.98, P<0.0001. CXCR4 expression is higher in HCC than those in cirrhosis as well, OR =20.71, 95% CI =7.61–56.34, P<0.00001. 2) The expression levels of CXCR4 does not increase during local progression, however, CXCR4 expression increases the risk of distant metastases in HCC, OR =5.84, 95% CI =2.84–12.00, P<0.00001. 3) High levels of CXCR4 gene expression are associated with worse survival in HCC, HR =0.18, 95% CI =0.10–0.32, Z=5.77, P<0.00001. These data indicate that CXCR4 expression correlates with an increased risk and worse survival in HCC patients. The aberrant CXCR4 expression plays an important role in the carcinogenesis and metastasis of HCC. Our conclusion also supports that the promise of CXCR4 signaling pathway blockade as a potential strategy for HCC patients.

Prognostic and predictive role of CXCR4, IGF-1R and Ezrin expression in localized synovial sarcoma: is chemotaxis important to tumor response?

BACKGROUND

Synovial sarcoma (SS) is a rare tumor, with dismal survival when metastatic. The role of adjuvant chemotherapy is debated. New prognostic and predictive factors are needed.

METHODS

We reviewed patients with localized SS; SS18-SSX fusion transcript presence was confirmed by FISH and RT-PCR. Expression of CXCR4, IGF-1R and Ezrin were evaluated by immunohistochemistry.

RESULTS

Tumor samples from 88 SS patients (45 female; 43 male) with median age 37 years (range 11-63) were selected. The size of the lesion was > 5 cm in 68% of patients and 34% of cases presented biphasic histotype. All patients underwent surgery, 56% adjuvant radiotherapy (RT), 65% adjuvant chemotherapy. A positive stain for IGF-1R was detected in 55 patients, with nucleus expression in 21 patients. CXCR4 was expressed in 74 patients, nuclear pattern in 31 patients. 80 SS were positive to Ezrin, 48 had cytoplasmatic location, 32 membrane location. With a median follow-up of 6 years (1-30 years), the 5-year overall survival (OS) was 70% (95% CI 60-81). 5-year OS was 63% (95% CI 41-85%) for patients with positive IGF-1R/nuclear expression, and 73% (95% CI 61-85%; P = 0.05) in negative patients. 5-year OS was 47% (95% CI 27-66%) in patients with positive CXCR4/nuclear staining, and 86% (95% CI 76-96%, P = 0.0003) in negative cases. No survival difference was found according to Ezrin expression. By multivariate analysis, nuclear expression of CXCR4 and IGF-1R was confirmed independent adverse prognostic factor for SS patient survival linked to the use of chemotherapy.

CONCLUSIONS

Our findings have important potential implications demonstrating that together with clinical prognostic factors such as radiotherapy and age, CXCR4 and IGF-1R negatively influences survival in patients with localized SS. We believe that further studies addressed to the effects of CXCR4 and IGF-1R inhibitors on cell viability and function are needed to plan new and more appropriate SS treatments.

Tumor type-specific and skin region-selective metastasis of human cancers: another example of the "seed and soil" hypothesis

Metastasis of human cancer is an organ-selective process that is determined by anatomical and biological factors as well as by specific microenvironmental properties. Dissemination of visceral malignancies to the skin is rather rare and usually occurs in a later stage of the disease. Using statistical approaches, both positive (renal and lung cancers) and negative (pancreatic and liver cancers) organ preferences can be identified in a variety of cancers. While certain cancer types are characterized by random distribution for skin metastasis (liver cancer), a number of cancers demonstrate a colonization preference to the region of origin: lung cancer to the supradiaphragmatic (mostly chest) and colorectal cancers to the infradiaphragmatic (abdominal) skin regions. In certain cases, however, skin metastasis develops more frequently at specific distant locations, as evidenced by the dissemination of renal cancer at the head and neck region. These findings are clinically relevant and useful especially in patients where skin metastasis is the first indication of a malignancy. Nevertheless, it is a strong argument for the predominant role of microenvironmental factors in cancer dissemination. On the other hand, skin metastases of visceral cancers provide a unique model to analyze the pathomechanisms determining organ selectivity, including the organ-specific vascularization, the dermatome-specific innervation, or immunological and developmental factors.

Recurrence patterns after resection of liver metastases from colorectal cancer

Recurrence of metastatic disease after resection of liver metastases from colorectal cancer remains a major problem as 70-80 % of patients will have a recurrence, most commonly in the liver or lung. To predict patterns of recurrence and outcome may guide follow-up and further treatment, as patients with recurrence might be candidates for repeated surgery or ablation therapy. A summary of studies shows that after hepatectomy 20-43 % will have a recurrence only in the remaining liver without extrahepatic disease, whereas 15-37 % will have a recurrence only to the lung. Early recurrence is associated with poorer outcome compared to late recurrence. Site of first recurrence after resection of liver metastases is predicted by several baseline variables; synchronous disease, primary tumor site, hepatic tumor size, CEA level, number of hepatic lesions, and RAS mutation status. Pattern of recurrence is a predictor for survival after hepatectomy, with liver-only and lung-only recurrences having the best survival. In the majority of patients with isolated hepatic or lung recurrence, repeated metastasectomy is possible resulting in a 40 % 5-year survival rate. Perioperative chemotherapy reduces the risk of liver recurrence after hepatectomy of colorectal cancer liver metastases.

Adjuvant therapy after resection of colorectal liver metastases: the predictive value of the MSKCC clinical risk score in the era of modern chemotherapy

BACKGROUND

Despite introduction of effective chemotherapy protocols, it has remained uncertain, if patients with colorectal cancer (CRC) liver metastases should receive adjuvant therapy. Clinical or molecular predictors may help to select patients at high risk for disease recurrence and death who obtain a survival advantage by adjuvant chemotherapy.

METHODS

A total of 297 patients with potentially curative resection of CRC liver metastases were analyzed. These patients had no neoadjuvant therapy, no extrahepatic disease and negative resection margins. The primary endpoint was overall survival. Patients' risk status was evaluated using the Memorial Sloan-Kettering Cancer Center clinical risk score (MSKCC-CRS). Multivariable analyses were performed using Cox proportional hazard models.

RESULTS

A total of 137 (43%) patients had a MSKCC-CRS > 2. Adjuvant chemotherapy was administered to 116 (37%) patients. Patients who received adjuvant chemotherapy were of younger age (p = 0.03) with no significant difference in the presence of multiple metastases (p = 0.72) or bilobar metastases (p = 0.08). On multivariate analysis adjuvant chemotherapy was associated with improved survival in the entire cohort (Hazard ratio 0.69; 95% confidence interval 0.69-0.98). It improved survival markedly in high-risk patients with a MSKCC-CRS > 2 (HR 0.40; 95% CI 0.23-0.69), whereas it was of no benefit in patients with a MSKCC-CRS ≤ 2 (HR 0.90; 95% CI 0.57-1.43).

CONCLUSIONS

The MSKCC-CRS offers a tool to select patients for adjuvant therapy after resection of CRC liver metastases. Validation in independent patient cohorts is required.

The association of CXCR4 expression with prognosis and clinicopathological indicators in colorectal carcinoma patients: a meta-analysis

AIMS

The clinical relevance of expression of chemokine receptor 4 (CXCR4) in colorectal carcinoma (CRC) remains controversial; our aim was to identify the precise relationship of CXCR4 to prognosis and clinicopathological features.

METHODS AND RESULTS

A meta-analysis was performed. Original data included the hazard ratios (HRs) of recurrence-free survival (RFS), overall survival (OS) and odds ratio (OR) in CRC patients. We pooled HR/OR with 95% confidence intervals (CIs) to estimate the hazard. A total of 20 published studies (including 2253 patients) were eligible. RFS and OS were related significantly to CXCR4 expression, with HRs 1.62 (95% CI 1.24-2.11; P < 0.0001) and 1.68 (95% CI 1.31-2.14; P < 0.0001), respectively. In addition, a significant association was revealed between positive CXCR4 expression and age (less than median age: OR 0.78, 95% CI 0.62-0.98; P = 0.03), stage (I and II: OR 0.46, 95% CI 0.32-0.66; P < 0.0001), grade (well/moderately differentiated: OR 0.74, 95% CI 0.56-0.98; P = 0.04), location (colon: OR: 0.73, 95% CI 0.57-0.95; P = 0.02), lymph node invasion (present: OR2.14, 95% CI 1.36-3.37; P = 0.001),and distant metastasis (present: OR 2.40; 95% CI 1.36-4.23; P = 0.003). Heterogeneity was observed among the included studies with regard to stage (I(2) = 58 %), lymph node invasiveness (I(2) = 74%) and distant metastasis (I(2) = 56%). No publication bias was observed.

CONCLUSIONS

Chemokine receptor 4 expression indicates poorer prognosis in older patients and advanced stage or poor differentiation in CRC, and also serves as an indicator of lymph node and distal organ metastasis. Surprisingly, high CXCR4 expression may indicate that the location of the tumour is the rectum. Thus, CXCR4 could help to predict outcome and guide clinical therapy.

Expression of CXCR4 is associated with progression and invasion in patients with nasal-surface basal cell carcinoma

BACKGROUND

Basal cell carcinoma (BCC) is the most common type of skin cancer with an increasing incidence worldwide that imposes a considerable burden on public health. C-X-C chemokine receptor (CXCR4) plays a vital role in initiation, progression and metastasis of several types of cancers. The aim of the present study was to investigate the expression and clinical significance of CXCR4 in BCC.

METHODS

In this study, 80 samples of primary BCC were assessed for CXCR4 expression using immunohistochemistry. The mRNA and protein expression levels of CXCR4 were evaluated by real-time reverse transcription polymerase chain reaction and Western blot analysis, respectively.

RESULTS

CXCR4-positive staining was detected in 70% of BCC samples. Overexpression of CXCR4 was significantly associated with tumor size (>2 vs. 2 cm, p = 0.002) and pathological type (invasive vs. noninvasive, p = 0.007). CXCR4 was also upregulated at transcriptional and translational levels.

CONCLUSION

Our study revealed that the expression of CXCR4 was associated with progression and invasion in patients with BCC. It may be a considerable biomarker to assess invasiveness of nasal-surface BCC and to guide clinical management of such tumors.

Patterns of recurrence after liver transplantation for nonresectable liver metastases from colorectal cancer

Background

Surgical resection is the only curative modality for colorectal liver metastases (CLM), and the pattern of recurrences after resection affects survival. In a prospective study of liver transplantation (Lt) for nonresectable CLM we have shown a 5-year overall survival rate of 60 %, but 19 of 21 experienced recurrence. This study reports the pattern of recurrences after Lt for CLM and the effect on survival.

Methods

Characterization of metastatic lesions in a prospective study for Lt for nonresectable CLM was performed (n = 21). The study included reexamination of chest computed tomographic scans taken before Lt.

Results

At the time of first recurrence, 16 were a single site, and three were multiple sites. Thirteen of the single sites were pulmonary recurrences. The pulmonary recurrences appeared early and were slow growing, and several were accessible to surgical treatment. When chest computed tomographic scans were reexamined, seven patients had pulmonary nodules at the time of Lt without an effect on survival. There was no first single-site hepatic recurrence. Six of the seven patients who developed metastases to the transplanted liver died from metastatic disease.

Conclusions

The pulmonary recurrences after Lt for CLM were of an indolent character, even those that were present at the time of Lt. This contrasts with the finding of metastases to the transplanted liver, which was prognostically adverse. The lack of single hepatic first-site recurrences and hepatic metastases only as part of disseminated disease is different from the pattern of recurrence after liver resection. This suggests two distinct mechanisms for hepatic recurrences after resection for CLM.

Emerging targets in cancer management: role of the CXCL12/CXCR4 axis

The chemokine CXCL12 (SDF-1) and its cell surface receptor CXCR4 were first identified as regulators of lymphocyte trafficking to the bone marrow. Soon after, the CXCL12/CXCR4 axis was proposed to regulate the trafficking of breast cancer cells to sites of metastasis. More recently, it was established that CXCR4 plays a central role in cancer cell proliferation, invasion, and dissemination in the majority of malignant diseases. The stem cell concept of cancer has revolutionized the understanding of tumorigenesis and cancer treatment. A growing body of evidence indicates that a subset of cancer cells, referred to as cancer stem cells (CSCs), plays a critical role in tumor initiation, metastatic colonization, and resistance to therapy. Although the signals generated by the metastatic niche that regulate CSCs are not yet fully understood, accumulating evidence suggests a key role of the CXCL12/CXCR4 axis. In this review we focus on physiological functions of the CXCL12/CXCR4 signaling pathway and its role in cancer and CSCs, and we discuss the potential for targeting this pathway in cancer management.

CXCR4 inhibition with AMD3100 sensitizes prostate cancer to docetaxel chemotherapy

Several in vitro and in vivo models have revealed the key role of CXCR4/CXCL12 axis in tumor-stroma interactions. Stromal cells present in the tumor microenvironment express high levels of CXCL12 protein, directly stimulating proliferation and migration of CXCR4-expressing cancer cells. This specific prosurvival influence of stromal cells on tumor cells is thought to protect them from cytotoxic chemotherapy and is postulated as a possible explanation for the minimal residual disease in hematological and solid cancers. Therefore, CXCR4/CXCL12 signaling is an attractive therapeutic target in cancer, as proven in preclinical leukemia mouse models, where CXCR4 inhibition sensitized cancer cells to conventional chemotherapy. This study investigates whether inhibition of CXCR4 with the specific inhibitor AMD3100 sensitizes human prostate cancer cells to docetaxel. We showed that both mouse and human stromal cell lines have a protective effect on PC3-luc cells by promoting their survival after chemotherapy. Furthermore, we demonstrated that AMD3100 sensitizes PC3-luc cells to docetaxel. In a subcutaneous xenograft mouse model of human prostate carcinoma, we showed that a combination of docetaxel and AMD3100 exerts increased antitumor effect compared with docetaxel alone. We concluded that CXCR4 inhibition chemosensitizes prostate cancer cells, both in vitro and in vivo. To explore the relevance of these findings, we analyzed CXCR4 expression levels in human prostate cancer samples. We found that cancer cells present in bone metastatic lesions express higher CXCR4 levels relative to the cells present in primary tumors and lymph node metastatic lesions. These findings underscore the potential of CXCR4 inhibitors as chemosensitizing agents.