Expression of the chemokine receptor CXCR4 in human hepatocellular carcinoma and its role in portal vein tumor thrombus

Identification of key molecules in the formation of portal vein tumor thrombus in hepatocellular carcinoma based on single cell transcriptomics and in vitro experiments

Background

The presence of portal vein tumor thrombus (PVTT) is a significant indicator of advanced-stage hepatocellular carcinoma (HCC). Unfortunately, the prediction of PVTT occurrence remains challenging, and there is a lack of comprehensive research exploring the underlying mechanisms of PVTT formation and its association with immune infiltration.

Methods

Our approach involved analyzing single-cell sequencing data, applying high dimensional weighted gene co-expression network analysis (hdWGCNA), and identifying key genes associated with PVTT development. Furthermore, we constructed competing endogenous RNA (ceRNA) networks and employed weighted gene co-expression network analysis (WGCNA), as well as three machine-learning techniques, to identify the upstream regulatory microRNAs (miRNAs) and long non-coding RNAs (lncRNAs) of the crucial mRNAs. We employed fuzzy clustering of time series gene expression data (Mfuzz), gene set variation analysis (GSVA), and cell communication analysis to uncover significant signaling pathways involved in the activation of these important mRNAs during PVTT development. In addition, we conducted immune infiltration analysis, survival typing, and drug sensitivity analysis using The Cancer Genome Atlas (TCGA) cohort to gain insights into the two patient groups under study.

Results

Through the implementation of hdWGCNA, we identified 110 genes that was closely associated with PVTT. Among these genes, TMEM165 emerged as a crucial candidate, and we further investigated its significance using COX regression analysis. Furthermore, through machine learning techniques and survival analysis, we successfully identified the upstream regulatory miRNA (hsa-miR-148a) and lncRNA (LINC00909) that targeted TMEM165. These findings shed light on the complex regulatory network surrounding TMEM165 in the context of PVTT. Moreover, we conducted CIBERSORT analysis, which unveiled correlations between TMEM165 and immune infiltration in HCC patients. Specifically, TMEM165 exhibited associations with various immune cell populations, including memory B cells and CD8+ T cells. Additionally, we observed implications for immune function, particularly in relation to immune checkpoints, within the context of HCC.

Conclusions

The regulatory axis involving TMEM165, hsa-miR-148a, and LINC00909 emerges as a crucial determinant in the development of PVTT in HCC patients, and it holds significant implications for prognosis. Furthermore, alterations in the TMEM165/hsa-miR-148a/LINC00909 regulatory axis exhibit a strong correlation with immune infiltration within the HCC tumor microenvironment, leading to immune dysfunction and potential failure of immunotherapy.

Progress on the molecular mechanism of portal vein tumor thrombosis formation in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most common malignant tumors, with poor prognosis and high mortality. Early-stage HCC has no obvious clinical symptoms, and most patients are already at an advanced stage when they are diagnosed. Portal vein tumor thrombus (PVTT) is the most common complication and a poor prognostic factor for HCC, which frequently leads to portal vein hypertension, ascites, gastrointestinal bleeding, and tumor metastasis. The formation of PVTT is related to the complex structure and hemodynamic changes of the portal vein and is closely related to changes at the cellular and molecular levels. The differentially-expressed genes (DEGs) between PVTT and primary tumor (PT) suggest that the two tissues may have different clonal origins. Epigenetic and proteomic analyses also suggest complex and diverse mechanisms for the formation of PVTT. In addition, the tumor microenvironment and energy metabolism pathways are interrelated in regulating the invasion and progression of PVTT. Aerobic glycolysis and the tumor immune microenvironment have been the focus of recent studies on PVTT. In this review, we summarize the mechanism of PVTT formation at the cellular and molecular levels to provide information to guide better prevention and treatment of PVTT in the clinic.

Portal vein tumor thrombosis in hepatocellular carcinoma: molecular mechanism and therapy

Portal vein tumor thrombosis (PVTT), a common complication of advanced hepatocellular carcinoma (HCC), remains the bottleneck of the treatments. Liver cancer cells potentially experienced multi-steps during PVTT process, including cancer cells leave from cancer nest, migrate in extracellular matrix, invade the vascular barrier, and colonize in the portal vein. Accumulated evidences have revealed numerous of molecular mechanisms including genetic and epigenetic regulation, cancer stem cells, immunosuppressive microenvironment, hypoxia, et al. contributed to the PVTT formation. In this review, we discuss state-of-the-art PVTT research on the potential molecular mechanisms and experimental models. In addition, we summarize PVTT-associated clinical trials and current treatments for PVTT and suppose perspectives exploring the molecular mechanisms and improving PVTT-related treatment for the future.

Is hepatocellular carcinoma complicated with portal vein tumor thrombosis potentially curable by radiotherapy in the form of stereotactic body radiation therapy?

PURPOSE

The prognosis of hepatocellular carcinoma (HCC) with portal vein tumor thrombosis (PVTT) is dismal. Despite best treatment and care, the patients with this malignancy only showed 2.7-4 months of overall survival. It is debatable whether liver transplantation helps PVTT sufferers. The effectiveness of radiation therapy in treating HCC patients with PVTT should not be undervalued. By limiting the high dosage region to a small planning target volume, stereotactic radiation delivery has shifted toward hypofractionation, limiting the radiation exposure to healthy organs and tissues. Stereotactic body radiotherapy (SBRT) has a local control rate of 75-100%, depending on the treatment. The major limitation in SBRT for hepatocellular carcinoma with PVTT is the paucity of prospective evidence for longer periods beyond the first two years after treatment. More prospective studies/randomized clinical trials with a longer follow-up, larger sample size, and adequate statistical power are the dire need of the present situation to ascertain the curative effect of SBRT as primary therapy for advanced HCC with PVTT.

CONCLUSION

SBRT can improve survival, particularly for patients receiving multidisciplinary treatment. This review sums up our most current understanding of how radiation therapy, notably SBRT, can be used to treat hepatocellular carcinoma when combined with PVTT. Recent research has led us to believe that irradiation in the form of SBRT may cure hepatocellular carcinoma complicated by PVTT.

CXCL12 Signaling in the Tumor Microenvironment

Tumor microenvironment (TME) is the local environment of tumor, composed of tumor cells and blood vessels, extracellular matrix (ECM), immune cells, and metabolic and signaling molecules. Chemokines and their receptors play a fundamental role in the crosstalk between tumor cells and TME, regulating tumor-related angiogenesis, specific leukocyte infiltration, and activation of the immune response and directly influencing tumor cell growth, invasion, and cancer progression. The chemokine CXCL12 is a homeostatic chemokine that regulates physiological and pathological process such as inflammation, cell proliferation, and specific migration. CXCL12 activates CXCR4 and CXCR7 chemokine receptors, and the entire axis has been shown to be dysregulated in more than 20 different tumors. CXCL12 binding to CXCR4 triggers multiple signal transduction pathways that regulate intracellular calcium flux, chemotaxis, transcription, and cell survival. CXCR7 binds with high-affinity CXCL12 and with lower-affinity CXCL11, which binds also CXCR3. Although CXCR7 acts as a CXCL12 scavenger through ligand internalization and degradation, it transduces the signal mainly through β-arrestin with a pivotal role in endothelial and neural cells. Recent studies demonstrate that TME rich in CXCL12 leads to resistance to immune checkpoint inhibitors (ICI) therapy and that CXCL12 axis inhibitors sensitize resistant tumors to ICI effect. Thus targeting the CXCL12-mediated axis may control tumor and tumor microenvironment exerting an antitumor dual action. Herein CXCL12 physiology, role in cancer biology and in composite TME, prognostic role, and the relative inhibitors are addressed.

New Insights on the Emerging Genomic Landscape of CXCR4 in Cancer: A Lesson from WHIM

Deciphering the molecular alterations leading to disease initiation and progression is currently crucial to identify the most relevant targets for precision therapy in cancer patients. Cancers express a complex chemokine network influencing leucocyte infiltration and angiogenesis. Moreover, malignant cells also express a selective repertoire of chemokine receptors that sustain their growth and spread. At present, different cancer types have been shown to overexpress C-X-C chemokine receptor type 4 (CXCR4) and to respond to its ligand C-X-C motif chemokine 12 (CXCL12). The CXCL12/CXCR4 axis influences cancer biology, promoting survival, proliferation, and angiogenesis, and plays a pivotal role in directing migration of cancer cells to sites of metastases, making it a prognostic marker and a therapeutic target. More recently, mutations in the C-terminus of CXCR4 have been identified in the genomic landscape of patients affected by Waldenstrom's macroglobulinemia, a rare B cell neoplasm. These mutations closely resemble those occurring in Warts, Hypogammaglobulinemia, Immunodeficiency, and Myelokathexis (WHIM) syndrome, an immunodeficiency associated with CXCR4 aberrant expression and activity and with chemotherapy resistance in clinical trials. In this review, we summarize the current knowledge on the relevance of CXCR4 mutations in cancer biology, focusing on its importance as predictors of clinical presentation and response to therapy.

Circulating tumor cells and CXCR4 in the prognosis of hepatocellular carcinoma

Background

This study was to determine circulating tumor cells (CTCs) and the expression of CXC chemokine receptor type 4 (CXCR4) in primary hepatocellular carcinoma (HCC) and the relationships with prognosis.

Methods

We used an advanced CanPatrol^TM CTC-enrichment technique to collect CTCs for isolation and characterization from blood samples. The RNA in situ hybridization (RNA-ISH) method, which is based on branched DNA (bDNA) signal amplification technology, was used to determine the expression of CXCR4 according to epithelial-mesenchymal transition (EMT) markers in 99 patients with primary liver cancer in blood samples pre-operatively. The relationship between the EMT markers and HCC was determined.

Results

The positive rates of CTCs and CXCR4 were 89.9% and 58.8%, respectively. CTCs were positively correlated with the Barcelona clinic liver cancer (BCLC) staging, tumor diameter and number, envelope, microsatellite damage, portal vein thrombosis, alpha-fetoprotein (AFP), and hepatitis B DNA, and negatively correlated with Edmondson grade. There were significant differences in the expression of CXCR4 between interstitial CTCs and mixed CTCs. A total of 99 patients underwent CTCs testing prior to surgery. The tumor-free survival time of HCC patients with interstitial CTCs <1 (13.3 months) was significantly longer than patients with interstitial CTCs ≥1 (5.0 months) pre-operatively.

Conclusions

CTC-positivity was shown to be associated with HCC and can be used as an independent prognostic factor for HCC. High CXCR4 protein expression was more common in mixed CTCs.

Progress in research of hepatocellular carcinoma with tumor thrombus

Hepatocellular carcinoma (HCC) with tumor thrombus is a hot and difficult issue in the study of HCC, and many key issues concerning this condition are still controversial. Clinical guidelines and treatment recommendations vary widely between the East and the West, and efficacy remains unsatisfactory. In recent years, with the progress of comprehensive tumor treatment concept and the rapid development of surgical techniques, perioperative management, interventional therapy, radiotherapy, targeted therapy, and other treatment methods, the overall survival rate of HCC with tumor thrombus has been significantly extended and encouraging efficacy has been achieved. However, the core issues on how to select individualized treatment to achieve optimal treatment and how to prevent postoperative recurrence still need to be studied and discussed. This article reviews the progress in the research of hepatic carcinoma with portal vein thrombus, inferior vena cava thrombus, or bile duct thrombus.

Edoxaban improves atrial fibrillation and thromboembolism through regulation of the Wnt-β-induced PI3K/ATK-activated protein C system

Thromboembolism is a commonly observed condition in geriatrics that is caused by vascular endothelial injury, platelet activation, physiological coagulation processes, reduction of anticoagulant activity, decreased fibrinolytic activity and abnormal flow in the heart chamber, artery or vein. The protein C anticoagulant system serves a crucial role in anticoagulant therapy for the treatment of thromboembolism. Previous findings have suggested that edoxaban is an efficient oral anticoagulant in the acute treatment of venous thromboembolism. In the present study, the efficacy of edoxaban on thromboembolism induced by atrial fibrillation was investigated in a mouse model. Inflammatory factors interleukin (IL)-1, −4, −8 and tumor necrosis factor (TNF)-α were analyzed in the sera of mice with fibrillation induced by thromboembolism. Expression and activity of thymic stromal lymphopoietin (TSLP) and activated protein C resistance were investigated in platelets and vascular endothelial cells (VECs). TSLP-induced platelet viability, Wnt-β phosphorylation and integrin expression were analyzed in platelets. Furthermore, Wnt-β expression and the phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT) signaling pathway in VECs were analyzed. Results demonstrated that the expression levels of IL-1, −4, −8 and TNF-α were significantly downregulated in the sera of mice with fibrillation and thromboembolism following treatment with edoxaban (P<0.01). Furthermore, the expression levels of prostacyclin (PGI2), prostaglandin (PG)E2, PGD2 and PGF2α were significantly increased in the sera of experimental mice that received edoxaban therapy (P<0.01). Results also indicated that edoxaban significantly stimulated the protein expression of TSLP and activated Wnt-β phosphorylation and integrin expression in platelets (P<0.01). In addition, edoxaban therapy significantly upregulated the expression levels of PI3K and AKT, and subsequently increased the activity of protein C and S in VECs (P<0.01). Notably, edoxaban treatment improved atrial fibrillation and thromboembolism, as determined by pathological analysis. In conclusion, these results suggested that edoxaban elicited beneficial effects for mice with atrial fibrillation induced by thromboembolism through the regulation of the Wnt-β-induced PI3K/ATK-activated protein C system.

Expression of the RAC1, RHOA and CXCR4 proteins and their interaction as risk factors for infiltration to the nipple areola complex in operable breast carcinoma

BACKGROUND

Nipple areola complex (NAC) infiltration in operable breast carcinoma (OBC) is associated with local recurrence. NAC infiltration in OBC suggests that RAC1, RHOA and CXCR4 proteins are risk factors for migration and infiltration of OBC to NAC. This study aims to analyze the expression and interactions of these proteins as risk factors for NAC infiltration in OBC.

MATERIALS AND METHODS

This is an analytic observational cross-sectional study coupled with a categorical comparative study in each 40 subjects of OBC with and without NAC infiltration. The immunohistochemistry performed with a cut-off point based on the result of a receiver operating characteristics (ROC).

RESULTS

RAC1, p < 0.001 with POR 5.76, 95% CI: 2.06-16.08; RHOA, p < 0.001 with POR 7.00, 95% CI: 2.28-21.53; and CXCR4, p = 0.001 with POR 6.33, 95% CI 2.06-19.49. There was an interaction between RAC1 and RHOA (p < 0.001 with POR 17.14, 95% CI: 3.07-125.66); between RAC1 and CXCR4 (p < 0.001 with POR 30.93, 95% CI 3.62-686.89); between RHOA and CXCR4 (p < 0.001 with POR 10.21, 95% CI 2.19-54.17); and between the RAC1, RHOA and CXCR4 proteins (p < 0.001 with POR = 23.69, 95% CI 2.51-544.86).

CONCLUSION

We conclude that the expression of the RAC1, RHOA, and CXCR4 proteins and their interactions play a role as risk factors of NAC infiltration.

Emerging Roles of G Protein-Coupled Receptors in Hepatocellular Carcinoma

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

MicroRNA-126 inhibits colon cancer cell proliferation and invasion by targeting the chemokine (C-X-C motif) receptor 4 and Ras homolog gene family, member A, signaling pathway

MicroRNA-126 (miR-126) suppresses the migration, proliferation and invasion of colon cancer cells. However, the underlying mechanisms of miR-126 in colon cancer have not been fully elucidated. In this study, in vivo experiments revealed that miR-126 inhibits colon cancer growth and metastasis. Furthermore, miR-126 was down-regulated in human colon cancer tissue, and its expression was inversely correlated with TNM stage and metastasis of patients. Low level of miR-126 identified patients with poor prognosis. And we found that miR-126 expression was negatively correlated with the expression levels of chemokine (C-X-C motif) receptor 4 (CXCR4) and components of signaling pathway of Ras homolog gene family, member A (RhoA) in vitro and in vivo. Moreover, we verified that miR-126 negatively regulated CXCR4 and RhoA signaling in vitro. In addition, either in miR-126-overexpressing or in miR- 126-silenced colon cancer cells, the restoration of CXCR4 could significantly reverse the proliferation and invasion, as well as abolish the effects of miR-126 on RhoA signaling pathway. Collectively, these results demonstrated that miR-126 acts as a tumor suppressor by inactivating RhoA signaling via CXCR4 in colon cancer. And miR-126 may serve as a prognostic marker for monitoring and treating colon cancer.

Privileged portal metastasis of hepatocellular carcinoma in light of the coevolution of a visceral portal system and liver in the chordate lineage: a search for therapeutic targets

Hepatocellular carcinoma (HCC) disseminates systemically, but metastases occur in distant organs only in minority of patients, whereas HCC routinely metastasizes to liver and its vessels. HCC cells disseminate via hepatic veins, but portal veins are affected by metastasis more frequently than are hepatic veins, and correlates with poor prognosis. In this review, I suggest that privileged HCC portal metastasis occurs because of high levels of pancreatic family hormones and growth factors (PHGFs) in the portal blood. The analysis suggests that the appearance of the portal system carrying PHGFs in the evolution of invertebrate chordate (Amphioxus) led to the evolution of the liver in vertebrate; given that the portal pattern of HCC metastasis and selection of more-aggressive clones are PHGF dependent, PHGFs and their ligands constitute therapeutic targets.

Somatostatin and CXCR4 chemokine receptor expression in hepatocellular and cholangiocellular carcinomas: tumor capillaries as promising targets

Background

Hepatocellular (HCC) and cholangiocellular carcinomas (CCC) display an exceptionally poor prognosis. Especially for advanced disease no efficient standard therapy is currently available. Recently, somatostatin analogs have been evaluated for the treatment of HCC, however, with contradictory results. Besides, for both malignancies the chemokine receptor CXCR4 has been discussed as a possible new target structure.

Methods

Expression of somatostatin receptor (SSTR) subtypes 1, 2A, 3, 4, and 5, and of CXCR4 was evaluated in a total of 71 HCCs and 27 CCCs by immunohistochemistry using well-characterized novel monoclonal antibodies.

Results

In HCC tumor cells, frequency and intensity of expression of SSTRs and CXCR4 were only low. CXCR4 was present in about 40% of the HCCs, although at a low intensity. SSTR5, SSTR2, and SSTR3 were detected in about 15%, 8%, and 5% of the HCC tumors, respectively. SSTR and CXCR4 expression was much higher in CCC than in HCC. CXCR4 and SSTR1 were present in 60% and 67% of the CCC samples, respectively, followed by SSTR2 and SSTR5, which were detected in 30% and 11% of the tumors, respectively. Most notably, CXCR4 was intensely expressed on the tumor capillaries in about 50% of the HCCs and CCCs. CXCR4 expression on tumor vessels was associated with poor patient outcomes.

Conclusions

CCC, but not HCC, may be suitable for SSTR-based treatments. Because of the predominant expression of SSTR1, pan-somatostatin analogs should be preferred. In both HCC and CCC, indirect targeting of tumors via the CXCR4-positive tumor capillaries may represent a promising additional therapeutic strategy.

Electronic supplementary material

The online version of this article (10.1186/s12885-017-3911-3) contains supplementary material, which is available to authorized users.

14-3-3ζ promotes hepatocellular carcinoma venous metastasis by modulating hypoxia-inducible factor-1α

Portal vein tumor thrombus (PVTT) is a type of intrahepatic metastasis arising from hepatocellular carcinoma (HCC) and is highly correlated with a poor prognosis. Hypoxia is common in solider tumors, including HCC, where it alters the behavior of HCC cells. We asked whether and how hypoxia contributes to PVTT formation. We demonstrated that increased intratumoral hypoxia is strongly associated with PVTT formation in HCC. We also showed that 14-3-3ζ is induced by hypoxia in HCC cells and correlates with PVTT formation in clinical HCC samples. In addition, 14-3-3ζ up-regulates HIF-1α expression by recruiting HDAC4, which prevents HIF-1α acetylation, thereby stabilizing the protein. Under hypoxic conditions in vitro, 14-3-3ζ knockdown inhibits hypoxia-induced HCC invasion by the HIF-1α/EMT pathway. Blockade of 14-3-3ζ in HCC cells reduces PVTT formation and distant lung metastasis in vivo. Moreover, a combination of 14-3-3ζ and HIF-1α expression is more prognostic for HCC patients than either protein alone. These results suggest that the hypoxia/14-3-3ζ/HIF-1α pathway plays an important role in PVTT formation and HCC metastasis.

Multidisciplinary management of hepatocellular carcinoma with portal vein tumor thrombus - Eastern Hepatobiliary Surgical Hospital consensus statement

Hepatocellular carcinoma (HCC) complicated by portal vein tumor thrombus (PVTT) is associated with poor prognosis, early recurrence of HCC, and limited treatment options. Current guidelines do not have standardized diagnostic and treatment modalities, thus creating a need for a multidisciplinary treatment model for standardization of the treatment. Eastern Hepatobiliary Surgical Hospital (China) convened two working parties of experts from all the departments, to consolidate the current evidence, prevailing vision for the future, and experience of the practicing clinicians engaged in HCC management, so as to develop a consensus for PVTT diagnosis and treatment according to the GRADE system. Based on the quality of the existing evidence and the strength of recommendations, the consensus statements were categorized into 3 evidence levels (A/B/C) and 5 classes (I/II/IIa/IIb/III).The panel discussed and provided clarity on the management and research options in the field of HCC with PVTT. In addition, the panel also assessed the quality of the cited studies and assigned grades to the recommendation statements. Among the group of experts, there was excellent agreement with regard to effective diagnosis and treatment of HCC with PVTT. The recommendations of this consensus will provide guidance to physicians and clinical researchers on the effective management of HCC with PVTT.

A meta-analysis for CXCR4 as a prognostic marker and potential drug target in non-small cell lung cancer

Background

Recent reports have shown that C-X-C chemokine receptor type 4 (CXCR4) is a candidate oncogene in several types of human tumors, including non-small cell lung cancer (NSCLC). However, the correlation between CXCR4 expression and clinicopathological characteristics of NSCLC remains controversial and has not been emphasized. The aim of this study is to quantitatively evaluate the association of CXCR4 expression with the incidence of NSCLC and clinicopathological characteristics by performing a meta-analysis.

Methods

A detailed literature search was carried out for related research publications. Only articles in which CXCR4 expression was detected by immunohistochemical staining were included. Odds ratio (OR) and hazard ratio (HR) with 95% confidence intervals (CIs) were calculated and summarized.

Results

Final analysis of 1,872 NSCLC patients from 19 eligible studies was performed. We observed that CXCR4 expression was significantly higher in NSCLC than in normal lung tissue, based on the pooled OR from ten studies, including 678 NSCLCs and 189 normal lung tissues (OR =16.66, 95% CI =6.94–40.02, P<0.00001). CXCR4 expression was also significantly associated with clinical stages, metastatic status, and overall survival (OS) in NSCLC patients. In addition, CXCR4 mRNA high expression was found to correlate with worse OS of all NSCLC patients followed for 20 years, HR =1.24, P=0.0047.

Conclusion

The present meta-analysis indicated that CXCR4 protein expression is associated with an increased risk and worse survival in NSCLC patients. The aberrant CXCR4 protein and mRNA expression play an important role in the carcinogenesis and metastasis of NSCLC.

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

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

Experimental study on enhancement of the metastatic potential of portal vein tumor thrombus-originated hepatocellular carcinoma cells using portal vein serum

OBJECTIVE

Portal vein metastasis of hepatocellular carcinoma (HCC) results in a poor prognosis and seriously affects the survival rate of patients. The mechanism underlying the formation of portal vein tumor thrombus (PVTT) is complex and is not yet fully understood. This study was conducted to investigate the impact of portal vein blood on the proliferation, metastasis, invasion and apoptosis of PVTT cells and to explore its possible mechanisms, which was expected to lay a foundation for ascertaining the mechanism underlying the portal vein metastasis of HCC.

METHODS

Peripheral blood and portal vein blood were collected from patients with HCC, and the sera from these two sources were used to culture the PVTT-originated HCC cell line CSQT-2. The cells were collected after 24 h, and flow cytometry was performed to detect cell proliferation, cell cycle stages and apoptosis. Transwell migration and invasion assays were applied to detect the metastasis and invasion of the cells in each group. The changes in the expression of MMP-2 and MMP-9 in cells were detected via Western blotting. The contents of IL-12, IFN-γ, IL-1β, IL-2 and TNF-α in the two groups of sera were quantified using corresponding kits.

RESULTS

Compared with the group of cells cultured with peripheral serum, the cells cultured with portal vein serum showed significantly lower apoptosis (P<0.01), significantly enhanced cell metastasis and invasion (P<0.01), whereas cell proliferation and the stages of the cell cycle did not differ significantly (P>0.05). A significantly increased expression level of MMP-2 has been observed in tumor cells treated portal vein serum. In addition, compared with peripheral serum, the content of IL-12 was significantly decreased in portal vein serum (P<0.05), while the contents of IFN-γ, IL-1β, IL-2, and TNF-α did not differ significantly (P>0.05).

CONCLUSIONS

Portal vein serum from HCC patients could inhibit the apoptosis of PVTT-originated HCC cells and promote cell metastasis and invasion. This effect may be related to the lower level of IL-12 in portal vein serum.

Insights on the CXCL12-CXCR4 axis in hepatocellular carcinoma carcinogenesis

Chemokines, a group of small chemotactic cytokines, and their G-protein-coupled receptors were originally identified for their ability to mediate various pro- and anti-inflammatory responses. Beyond the influence of chemokines and their cognate receptors in several inflammatory diseases, several malignancies have been shown to be dependent of chemokines for progression, tumor growth, cellular migration and invasion, and angiogenesis; those later facilitating the development of distant metastases. In hepatocellular carcinoma (HCC), chemokines were shown to affect leukocyte recruitment, neovascularization and tumor progression. CXCL12 (stromal-derived factor 1 alpha- SDF-1) is the primary ligand for the seven transmembrane G-protein coupled receptor CXCR4. The CXCR4/CXCL12 axis exerts a variety of functions at different steps of HCC tumor progression, using autocrine and/or paracrine mechanisms to sustain tumor cell growth, to induce angiogenesis and to facilitate tumor escape through evasion of immune surveillance. In this review, we have comprehensively described the role of CXCR4/CXCL12 in HCC and also investigated the role of CXCR7, an alternative receptors that also binds CXCL12 with potentially distinct downstream effects. Preclinical data converge to demonstrate that inhibition of the CXCR4/CXCL12 axis may lead to direct inhibition of tumor migration, invasion, and metastases. This pathway is under investigation to identify potential novel treatments in HCC and other cancers. However, one of the major challenges faced in this emerging field targeting the CXCR4/CXCL12 signaling pathway, is the translation of current knowledge into the design and development of effective inhibitors of CXCR4 and/or CXCL12 for cancer therapy.

Association of CXC chemokine receptor type 4 expression and clinicopathologic features in human vulvar cancer

OBJECTIVE

Although CXC chemokine receptor type 4 (CXCR4) is known to be expressed in various solid tumors and plays an integral role in cancer invasion and metastasis, expression of CXCR4 in human vulvar cancer has not yet been investigated. We examined distribution and expression of this chemokine receptor in specimens of invasive and noninvasive human vulvar neoplasms to elucidate its clinical significance.

METHODS

Study patients were 38 consecutive patients (31 with primary vulvar cancers and 7 with intraepithelial neoplasms) treated at one of our hospitals. Sections of all specimens were evaluated for CXCR4 expression by means of immunohistochemistry. Relations between CXCR4 expression and clinicopathologic features including prognosis were investigated.

RESULTS

None of the 7 vulvar intraepithelial lesions expressed CXCR4. Of the 31 invasive vulvar tumor samples examined, 19 (61%) stained positively for CXCR4; 15 (68%) of 22 squamous cell carcinomas and 2 (29%) of 7 Paget tumors were CXCR4 positive. The difference in expression between invasive cancers and intraepithelial neoplasms was significant (P = 0.003). FIGO (International Federation of Gynecology and Obstetrics) stage III-IV cancers, in comparison to FIGO stage I-II cancers, were more likely to be positive for CXCR4 (82% vs 50%, P = 0.08). In terms of disease-free survival, prognosis of cancers that expressed CXCR4 was poorer than that of CXCR4-negative cancers (P = 0.013), but in terms of disease-specific survival, prognosis did not differ significantly between CXCR4-positive and -negative cancers (P = 0.111).

CONCLUSIONS

More than half of invasive squamous cell vulvar cancers can be expected to express CXCR4, and CXCR4 expression correlates with poor disease prognosis.

Overactivation of the TGF-β pathway confers a mesenchymal-like phenotype and CXCR4-dependent migratory properties to liver tumor cells

Transforming growth factor-beta (TGF-β) is an important regulatory suppressor factor in hepatocytes. However, liver tumor cells develop mechanisms to overcome its suppressor effects and respond to this cytokine by inducing other processes, such as the epithelial-mesenchymal transition (EMT), which contributes to tumor progression and dissemination. Recent studies have placed chemokines and their receptors at the center not only of physiological cell migration but also of pathological processes, such as metastasis in cancer. In particular, CXCR4 and its ligand, stromal cell-derived factor 1α (SDF-1α) / chemokine (C-X-C motif) ligand 12 (CXCL12) have been revealed as regulatory molecules involved in the spreading and progression of a variety of tumors. Here we show that autocrine stimulation of TGF-β in human liver tumor cells correlates with a mesenchymal-like phenotype, resistance to TGF-β-induced suppressor effects, and high expression of CXCR4, which is required for TGF-β-induced cell migration. Silencing of the TGF-β receptor1 (TGFBR1), or its specific inhibition, recovered the epithelial phenotype and attenuated CXCR4 expression, inhibiting cell migratory capacity. In an experimental mouse model of hepatocarcinogenesis (diethylnitrosamine-induced), tumors showed increased activation of the TGF-β pathway and enhanced CXCR4 levels. In human hepatocellular carcinoma tumors, high levels of CXCR4 always correlated with activation of the TGF-β pathway, a less differentiated phenotype, and a cirrhotic background. CXCR4 concentrated at the tumor border and perivascular areas, suggesting its potential involvement in tumor cell dissemination.

CONCLUSION

A crosstalk exists among the TGF-β and CXCR4 pathways in liver tumors, reflecting a novel molecular mechanism that explains the protumorigenic effects of TGF-β and opens new perspectives for tumor therapy.

Chemokines, chemokine receptors and the gastrointestinal system

The biological properties of tumor cells are known to be regulated by a multitude of cytokines and growth factors, which include epidermal growth factor receptor agonists and members of the transforming growth factor β family. Furthermore, the recent explosion of research in the field of chemokine function as mediators of tumor progression has led to the possibility that these small, immunomodulatory proteins also play key roles in carcinogenesis and may, therefore, be potential targets for novel therapeutic approaches. In this review, we will summarize recently reported findings in chemokine biology with a focus on the gastrointestinal tract.

Capturing circulating tumor cells of hepatocellular carcinoma

Early metastases of hepatocellular carcinoma (HCC) may be detected by the isolation of circulating tumor cells (CTCs) in the bloodstream. During the course of therapeutic attempts, monitoring CTC changes in patients with HCC is helpful for the efficacy assessment. Nevertheless, the markers used for the detection, such as α-feto protein, asialoglycoprotein receptor or epithelial cell adhesion molecule, CD133 or CD90, are not specific for HCC CTCs. In spite of these limitations, a timely determination of the existence of CTCs will be beneficial for the monitoring of distant metastases, the evaluation of therapeutic attempts, and the prediction of prognosis.

Circulating tumor cells measurements in hepatocellular carcinoma

Liver cancer is the fifth most common cancer in men and the seventh in women. During the past 20 years, the incidence of HCC has tripled while the 5-year survival rate has remained below 12%. The presence of circulating tumor cells (CTC) reflects the aggressiveness nature of a tumor. Many attempts have been made to develop assays that reliably detect and enumerate the CTC during the development of the HCC. In this case, the challenges are (1) there are few markers specific to the HCC (tumor cells versus nontumor cells) and (2) they can be used to quantify the number of CTC in the bloodstream. Another technical challenge consists of finding few CTC mixed with million leukocytes and billion erythrocytes. CTC detection and identification can be used to estimate prognosis and may serve as an early marker to assess antitumor activity of treatment. CTC can also be used to predict progression-free survival and overall survival. CTC are an interesting source of biological information in order to understand dissemination, drug resistance, and treatment-induced cell death. Our aim is to review and analyze the different new methods existing to detect, enumerate, and characterize the CTC in the peripheral circulation of patients with HCC.