Identification and clinical significance of mobilized endothelial progenitor cells in tumor vasculogenesis of hepatocellular carcinoma

Crosstalk between endothelial progenitor cells and HCC through periostin/CCL2/CD36 supports formation of the pro-metastatic microenvironment in HCC

Metastasis causes most cancer-related deaths, and the role and mechanism of periostin (POSTN) in the metastasis of hepatocellular carcinoma (HCC) remain undiscovered. In this study, DEN and HTVi HCC models were performed in hepatic-specific Postn ablation and Postn knock-in mouse to reveal the role of POSTN in HCC metastasis. Furthermore, POSTN was positively correlated with circulating EPCs level and promoted EPC mobilization and tumour infiltration. POSTN also mediated the crosstalk between HCC and EPCs, which promoted metastasis ability and upregulated CD36 expression in HCC through indirect crosstalk. Chemokine arrays further revealed that hepatic-derived POSTN induced elevated CCL2 expression and secretion in EPCs, and CCL2 promoted prometastatic traits in HCC. Mechanistic studies showed that POSTN upregulated CCL2 expression in EPCs via the αvβ3/ILK/NF-κB pathway. CCL2 further induced CD36 expression via the CCR2/STAT3 pathway by directly binding to the promoter region of CD36. Finally, CD36 was verified to have a prometastatic role in vitro and to be correlated with POSTN expression, metastasis and recurrence in HCC in clinical samples. Our findings revealed that crosstalk between HCC and EPCs is mediated by periostin/CCL2/CD36 signalling which promotes HCC metastasis and emphasizes a potential therapeutic strategy for preventing HCC metastasis.

To be or not to be: endothelial cell plasticity in development, repair, and disease

Endothelial cells display an extraordinary plasticity both during development and throughout adult life. During early development, endothelial cells assume arterial, venous, or lymphatic identity, while selected endothelial cells undergo additional fate changes to become hematopoietic progenitor, cardiac valve, and other cell types. Adult endothelial cells are some of the longest-lived cells in the body and their participation as stable components of the vascular wall is critical for the proper function of both the circulatory and lymphatic systems, yet these cells also display a remarkable capacity to undergo changes in their differentiated identity during injury, disease, and even normal physiological changes in the vasculature. Here, we discuss how endothelial cells become specified during development as arterial, venous, or lymphatic endothelial cells or convert into hematopoietic stem and progenitor cells or cardiac valve cells. We compare findings from in vitro and in vivo studies with a focus on the zebrafish as a valuable model for exploring the signaling pathways and environmental cues that drive these transitions. We also discuss how endothelial plasticity can aid in revascularization and repair of tissue after damage- but may have detrimental consequences under disease conditions. By better understanding endothelial plasticity and the mechanisms underlying endothelial fate transitions, we can begin to explore new therapeutic avenues.

The Role of Endoglin in Hepatocellular Carcinoma

Endoglin (CD105) is a type-1 integral transmembrane glycoprotein and coreceptor for transforming growth factor-β (TGF-β) ligands. The endoglin/TGF-β signaling pathway regulates hemostasis, cell proliferation/migration, extracellular matrix (ECM) synthesis and angiogenesis. Angiogenesis contributes to early progression, invasion, postoperative recurrence, and metastasis in hepatocellular carcinoma (HCC), one of the most widespread malignancies globally. Endoglin is overexpressed in newly formed HCC microvessels. It increases microvessel density in cirrhotic and regenerative HCC nodules. In addition, circulating endoglin is present in HCC patients, suggesting potential for use as a diagnostic or prognostic factor. HCC angiogenesis is dynamic and endoglin expression varies by stage. TRC105 (carotuximab) is an antibody against endoglin, and three of its clinical trials were related to liver diseases. A partial response was achieved when combining TRC105 with sorafenib. Although antiangiogenic therapy still carries some risks, combination therapy with endoglin inhibitors or other targeted therapies holds promise.

Efficacy and biomarker analysis of CD133-directed CAR T cells in advanced hepatocellular carcinoma: a single-arm, open-label, phase II trial

Expressed by cancer stem cells of various epithelial cell origins and hepatocellular carcinoma (HCC), CD133 is an attractive therapeutic target for HCC. The marker CD133 is highly expressed in endothelial progenitor cells (EPC). EPCs circulate in increased numbers in the peripheral blood of patients with highly vascularized HCC and contribute to angiogenesis and neovascularization. This phase II study investigated CD133-directed chimeric antigen receptor (CAR) T (CART-133) cells in adults with HCC. Patients with histologically confirmed and measurable advanced HCC and adequate hematologic, hepatic, and renal functions received CART-133 cell infusions. The primary endpoints were safety in phase I and progression-free survival (PFS) and overall survival (OS) in phase II. Other endpoints included biomarkers for CART-133 T cell therapy. Between June 1, 2015, and September 1, 2017, this study enrolled 21 patients who subsequently received CART-133 T cells across phases I and II. The median OS was 12 months (95% CI, 9.3–15.3 months) and the median PFS was 6.8 months (95% CI, 4.3–8.4 months). Of 21 evaluable patients, 1 had a partial response, 14 had stable disease for 2 to 16.3 months, and 6 progressed after T-cell infusion. The most common high-grade adverse event was hyperbilirubinemia. Outcome was correlated with the baseline levels of vascular endothelial growth factor (VEGF), soluble VEGF receptor 2 (sVEGFR2), stromal cell-derived factor (SDF)-1, and EPC counts. Changes in EPC counts, VEGF, SDF-1, sVEGFR2, and interferon (IFN)-γ after cell infusion were associated with survival. In patients with previously treated advanced HCC, CART-133 cell therapy demonstrates promising antitumor activity and a manageable safety profile. We identified early changes in circulating molecules as potential biomarkers of response to CART-133 cells. The predictive value of these proangiogenic and inflammatory factors as potential biomarkers of CART-133 cell therapy in HCC will be explored in prospective trials. This study is registered at ClinicalTrials.gov (NCT02541370)

High expression of endothelial progenitor cell-induced angiogenic markers is associated with bile acid levels in HCC

Endothelial progenitor cell (EPC)-induced angiogenesis activity is enhanced in hepatocellular carcinoma (HCC); however, the contributing factors remain unknown. The present study aimed to investigate the factors influencing the number of EPCs and circulating progenitor cells (CPCs), as well as the expression levels of vascular endothelial growth factor receptor 2 (VEGFR-2) and CD34, in patients with HCC. The expression levels of VEGFR-2 and CD34 were assessed in 72 HCC tumor and matched adjacent tissue microarrays by immunohistochemistry. The associations between VEGFR-2 or CD34 expression in tumors, clinicopathological characteristics and overall survival rates were analyzed. The number of EPCs and CPCs were analyzed in the peripheral blood of patients with HCC. In this study, high expression levels of VEGFR-2 and CD34 were detected in the tumor tissues of 41 (56.9%) and 44 (61.1%) patients, respectively. VEGFR-2 expression was significantly associated with tumor size (P<0.001), bile acid level (P=0.014) and α-fetoprotein level (P=0.011). However, CD34 expression was associated with tumor size (P=0.009), recrudescence (P<0.001) and bile acid (P=0.009). Next, the expression levels of VEGFR-2 and CD34 in tumor and adjacent tissues were compared according to the bile acid level. VEGFR-2 and CD34 expression levels were both higher in the high bile acid group, whereas expression levels of the markers were higher in adjacent tissues compared with tumor tissues. Kaplan-Meier curve analysis identified that patients with low CD34 expression had a longer overall survival compared with patients with high CD34 expression (P=0.029). Multivariate analysis also indicated that both VEGFR-2 (P=0.020) and CD34 (P=0.035) were independent prognostic risk factors. Moreover, flow cytometry demonstrated that the number of EPCs and CPCs was negatively related with the bile acid levels in patients with HCC. In conclusion, in patients with HCC, bile acid promotes EPC-induced angiogenesis. Furthermore, EPCs and CPCs may be activated by bile acid in tumors but are more so in adjacent tissues.

Monocytes and Macrophages in Cancer: Unsuspected Roles

The behavior of cancer is undoubtedly affected by stroma. Macrophages belong to this microenvironment and their presence correlates with reduced survival in most cancers. After a tumor-induced "immunoediting", these monocytes/macrophages, originally the first line of defense against tumor cells, undergo a phenotypic switch and become tumor-supportive and immunosuppressive.The influence of these tumor-associated macrophages (TAMs) on cancer is present in all traits of carcinogenesis. These cells participate in tumor initiation and growth, migration, vascularization, invasion and metastasis. Although metastasis is extremely clinically relevant, this step is always reliant on the angiogenic ability of tumors. Therefore, the formation of new blood vessels in tumors assumes particular importance as a limiting step for disease progression.Herein, the once unsuspected roles of macrophages in cancer will be discussed and their importance as a promising strategy to treat this group of diseases will be reminded.

Clinical significance of endothelial progenitor cells in patients with liver cirrhosis with or without hepatocellular carcinoma

BACKGROUND AND OBJECTIVE

The role of endothelial progenitor cells in patients with cirrhosis has seldom been investigated. This study was conducted to assess the clinical significance of circulating endothelial progenitor cells in patients with liver cirrhosis with or without hepatocellular carcinoma.

METHODS

A blood sample was collected once from patients with cirrhosis alone (n = 34) or cirrhosis and hepatocellular carcinoma (n = 46) and healthy controls (n = 27) for assessing levels of endothelial progenitor cells and vascular endothelial growth factor. Blood cells staining positive for CD34/CD133/KDR using flow cytometry were characterized as endothelial progenitor cells. Plasma vascular endothelial growth factor was quantified by ELISA.

RESULTS

The levels of CD34/KDR-positive endothelial progenitor cells, CD133/KDR-positive endothelial progenitor cells, and vascular endothelial growth factor were higher in patients with cirrhosis ± hepatocellular carcinoma than in healthy controls (P = 0.017, P < 0.001 and P < 0.001, respectively). The levels of endothelial progenitor cells and vascular endothelial growth factor did not show statistical difference according to Child-Turcotte-Pugh class. There was a moderately significant correlation between vascular endothelial growth factor levels and hepatocellular carcinoma stage (ρ = 0.464, P = 0.001). Smoking, ascites, and portal vein thrombosis were independently related to lower levels of circulating CD34/KDR-positive endothelial progenitor cells, higher levels of CD133/KDR-positive endothelial progenitor cells, and higher levels of vascular endothelial growth factor, respectively (P = 0.041, P = 0.023, and P < 0.001, respectively).

CONCLUSION

Circulating endothelial progenitor cells and plasma vascular endothelial growth factor levels were higher in patients with liver cirrhosis ± hepatocellular carcinoma compared to healthy controls. The increase in endothelial progenitor cells and vascular endothelial growth factor may have a possible role in the development of complications, especially ascites and portal vein thrombosis, or in progression of hepatocellular carcinoma.

Circulating hematopoietic stem cells, endothelial progenitor cells and cancer stem cells in hepatocellular carcinoma patients: contribution to diagnosis and prognosis

Background and aim: Circulating hematopoietic stem cells (HSCs), circulating endothelial progenitor cells (EPCs) and cancer stem cells (CSCs) contribute to tumor development and progression and can predict patient outcome. The aim of this study was to investigate the frequency of circulating HSCs, EPCs and CSCs in the peripheral blood of patients with hepatocellular carcinoma (HCC) and to explore their potential prognostic significance for HCC patients.Methods: The study included 30 HCC patients and 20 healthy controls. The HSCs and EPCs were enumerated with CD45, CD34, CD133, CD144 markers, while CSCs were enumerated with CD45, CD44, CD133 markers using flow cytometry.Results: The mean percentages of circulating HSCs were significantly lower in HCC patients than the controls (p = .001), whereas the mean percentages of EPCs within the HSCs subpopulation were significantly higher in the HCC patients than the controls (p = .002). The absolute count of CSCs within 100,000 peripheral blood mononuclear cells was 23.5 ± 3.4 in the HCC patients. Also, the mean percentages of circulating HSCs, EPCs and the number of CSCs were significantly increased in patients with multiple hepatic focal lesions than in patients with a single hepatic focal lesion. Both circulating HSCs and EPCs showed significant positive correlation with the level of AFP and with the numbers of CSCs. In the meantime, the numbers of CSCs revealed significant direct correlation with ALT, AST and AFP levels. The one-year overall survival (OS) of the patients was 77.5%. High levels of CSCs, HSCs and EPCs at diagnosis were all associated with worse outcome for the HCC patients.Conclusions: Significant changes in the levels of the circulating HSCs, EPCs and CSCs occur in HCC. These changes help the diagnosis and the prediction of HCC outcome, as higher levels of these cells are associated with worse OS.

Circulating tumor DNA/circulating tumor cells and the applicability in different causes induced hepatocellular carcinoma

In 2015, liquid biopsy was rated one of the top 10 breakthrough technologies of the year by MIT Technology Review. Liquid biopsy is a type of in vitro diagnostic method involving a noninvasive blood test. It is also a breakthrough technology used to detect tumors and cancers and assist in therapeutic strategies. The most widely used markers are circulating tumor cells (CTCs) and circulating tumor DNA (ctDNA). Primary carcinoma of the liver is a malignancy of hepatocytes or intrahepatic biliary epithelial cells. The most common type of liver cancer is hepatocellular carcinoma (HCC), the causes of which mainly include infection with hepatitis B virus (HBV) and/or hepatitis C virus (HCV), alcohol abuse, aflatoxicosis, and nonalcoholic fatty liver disease/ nonalcoholic steatohepatitis. As there are few typical clinical characteristics during the early stage of the disease, early diagnosis of HCC is very challenging. However, CTCs and ctDNA carry tumor-specific information. Therefore, the detection and analysis of CTCs and ctDNA can provide evidence for the early diagnosis of HCC and guide treatment. Furthermore, several studies have indicated that different inducers of HCC cause different DNA mutations, and accordingly, detection of specific mutations in ctDNA will facilitate the determination of the HCC type and help physicians provide distinctive therapies.

Garcimultiflorone K inhibits angiogenesis through Akt/eNOS- and mTOR-dependent pathways in human endothelial progenitor cells

Background Garcimultiflorone K is a novel polyprenylated polycyclic acylphloroglucinol isolated from the stems of Garcinia multiflora that exhibits promising anti-angiogenic activity in human endothelial progenitor cells (EPCs). Purpose This study sought to determine the underlying anti-angiogenic mechanisms and pharmacological properties of garcimultiflorone K. Methods We examined the anti-angiogenic effects of garcimultiflorone K and its mechanisms of action using in vitro EPC models and in vivo zebrafish embryos. Results EPCs proliferation, migration, differentiation and capillary-like tube formation were effectively and concentration-dependently inhibited by garcimultiflorone K without any signs of cytotoxicity. Our investigations revealed that garcimultiflorone K suppressed EPCs angiogenesis through Akt, mTOR, p70S6K, and eNOS signaling cascades. Notably, garcimultiflorone K dose-dependently impeded angiogenesis in zebrafish embryos. Conclusion Our data demonstrate the anti-angiogneic effects of garcimultiflorone K in both in vitro and in vivo models. Garcimultiflorone K appears to have potential in the treatment of angiogenesis-related diseases.

Role of Endoglin (CD105) in the Progression of Hepatocellular Carcinoma and Anti-Angiogenic Therapy

The liver is perfused by both arterial and venous blood, with a resulting abnormal microenvironment selecting for more-aggressive malignancies. Hepatocellular carcinoma (HCC) is the most frequent primary liver cancer, the sixth most common cancer globally, and the third leading cause of cancer-related mortality worldwide. HCC is characterized by its hypervascularization. Improving the efficiency of anti-angiogenic treatment and mitigation of anti-angiogenic drug resistance are the top priorities in the development of non-surgical HCC therapies. Endoglin (CD105), a transmembrane glycoprotein, is one of the transforming growth factor β (TGF-β) co-receptors. Involvement of that protein in angiogenesis of solid tumours is well documented. Endoglin is a marker of activated endothelial cells (ECs), and is preferentially expressed in the angiogenic endothelium of solid tumours, including HCC. HCC is associated with changes in CD105-positive ECs within and around the tumour. The large spectrum of endoglin effects in the liver is cell-type- and HCC- stage-specific. High expression of endoglin in non-tumour tissue suggests that this microenvironment might play an especially important role in the progression of HCC. Evaluation of tissue expression, as well as serum concentrations of this glycoprotein in HCC, tends to confirm its role as an important biomarker in HCC diagnosis and prognosis. The role of endoglin in liver fibrosis and HCC progression also makes it an attractive therapeutic target. Despite these facts, the exact molecular mechanisms of endoglin functioning in hepatocarcinogenesis are still poorly understood. This review summarizes the current data concerning the role and signalling pathways of endoglin in hepatocellular carcinoma development and progression, and provides an overview of the strategies available for a specific targeting of CD105 in anti-angiogenic therapy in HCC.

Insights into Endothelial Progenitor Cells: Origin, Classification, Potentials, and Prospects

With the discovery of endothelial progenitor cells (EPCs) in the late 1990s, a paradigm shift in the concept of neoangiogenesis occurred. The identification of circulating EPCs in peripheral blood marked the beginning of a new era with enormous potential in the rapidly transforming regenerative field. Overwhelmed with the revelation, researchers across the globe focused on isolating, defining, and interpreting the role of EPCs in various physiological and pathological conditions. Consequently, controversies emerged regarding the isolation techniques and classification of EPCs. Nevertheless, the potential of using EPCs in tissue engineering as an angiogenic source has been extensively explored. Concomitantly, the impact of EPCs on various diseases, such as diabetes, cancer, and cardiovascular diseases, has been studied. Within the limitations of the current knowledge, this review attempts to delineate the concept of EPCs in a sequential manner from the speculative history to a definitive presence (origin, sources of EPCs, isolation, and identification) and significance of these EPCs. Additionally, this review is aimed at serving as a guide for investigators, identifying potential research gaps, and summarizing our current and future prospects regarding EPCs.

The Impact of Liver Graft Injury on Cancer Recurrence Posttransplantation

Liver transplantation is the most effective treatment for selected patients with hepatocellular carcinoma. However, cancer recurrence, posttransplantation, remains to be the critical issue that affects the long-term outcome of hepatocellular carcinoma recipients. In addition to tumor biology itself, increasing evidence demonstrates that acute-phase liver graft injury is a result of hepatic ischemia reperfusion injury (which is an inevitable consequence during liver transplantation) and may promote cancer recurrence at late phase posttransplantation. The liver grafts from living donors, donors after cardiac death, and steatotic donors have been considered as promising sources of organs for liver transplantation and are associated with high incidence of liver graft injury. The acute-phase liver graft injury will trigger a series of inflammatory cascades, which may not only activate the cell signaling pathways regulating the tumor cell invasion and migration but also mobilize the circulating progenitor and immune cells to facilitate tumor recurrence and metastasis. The injured liver graft may also provide the favorable microenvironment for tumor cell growth, migration, and invasion through the disturbance of microcirculatory barrier function, induction of hypoxia and angiogenesis. This review aims to summarize the latest findings about the role and mechanisms of liver graft injury resulted from hepatic ischemia reperfusion injury on tumor recurrence posttransplantation, both in clinical and animal cohorts.

Acidic stress induces apoptosis and inhibits angiogenesis in human bone marrow-derived endothelial progenitor cells

Bone marrow-derived endothelial progenitor cells (BM-EPCs) are exposed to acidotic environments in a variety of physiological and pathological conditions, including in tumors. However, the effect of acidosis on the function of BM-EPCs is still not fully understood. In the present study, BM-EPCs were isolated and cultured at an extracellular pH (pHe) of 6.5 or pHe 7.4 in vitro prior to various experiments being performed. Cellular proliferation, migration and tube formation ability were detected by DNA content quantification, Transwell assay and Matrigel-based angiogenesis assay. ELISA and western blot analysis measured protein secretion and expression, respectively. The results demonstrated that BM-EPCs cultured at pHe 6.5 compared with at pHe 7.4 demonstrated: Induced apoptosis; inhibited cellular proliferation, migration and adhesion; markedly reduced vascular endothelial growth factor (VEGF) expression; and the capacity to incorporate into vascular networks. Acidic pHe 6.5 induced ratio expression of B-cell lymphoma 2 (Bcl2)/Bcl2 associated X-protein (Bax), which in turn induced apoptosis, and inhibited cellular proliferation and other functional activities, with involvement of activation of VEGF receptor 2, protein kinase B and p38 mitogen activated protein kinase. These observations raise the possibility that the acidic extracellular environment may perform an important role in the vasculogenesis of BM-EPCs in tumor microenvironments. Therefore, culturing cancer cells at a lower pH that simulates endogenous tumor conditions may improve retention of the cellular heterogeneity identified in tumors.

Bone marrow endothelial progenitor cells activate hepatic stellate cells and aggravate carbon tetrachloride induced liver fibrosis in mice via paracrine factors

OBJECTIVES

Bone marrow derived endothelial progenitor cells (BM-EPCs) are increased in chronic liver disease (CLD). Their role in hepatic fibrosis and regeneration remains an area of intense studies. We investigated the migration and secretory functions of BM-EPCs in fibrotic mice liver.

MATERIALS AND METHODS

Bone marrow cells from C57BL6-GFP mice were transplanted into the femur of irradiated C57BL6 mice, followed by CCl₄ doses for 8 weeks, to develop hepatic fibrosis (n = 36). Transplanted C57BL6 mice without CCl₄ treatment were used as controls. EPCs were analyzed in BM, blood and liver by flow cytometry and immunofluorescence. VEGF and TGF-β were analysed in the hepatic stellate cells (HSCs) and BM-EPCs co-cultures using ELISAs.

RESULTS

There was a significant migration of EPCs from BM to blood and to the liver (P ≤ 0.01). Percentage of GFP⁺ CD31⁺ EPCs and collagen proportionate area was substantially increased in the liver at 4th week of CCl₄ dosage compared to the controls (19.8% vs 1.9%, P ≤ 0.05). Levels of VEGF (533.6 pg/ml) and TGF-β (327.44 pg/ml) also increased significantly, when HSCs were treated with the EPC conditioned medium, as compared to controls (25.66 pg/ml and 5.87 pg/ml, respectively; P ≤ 0.001).

CONCLUSIONS

Present findings suggest that BM-EPCs migrate to the liver during CCl4-induced liver injury and contribute to fibrosis.

Circulating endothelial cells and risk of progression in patients with hepatocellular cancer receiving sorafenib

Aim

We investigated the behavior of circulating endothelial cells (CEC) in patients with hepatocellular carcinoma (HCC) receiving sorafenib, and whether CEC levels were associated with time to progression (TTP).

Materials & methods

CECs in advanced HCC patients receiving sorafenib were counted at baseline and every 4 weeks.

Results

Twenty four HCC patients were enrolled in the study. Median TTP was 3.2 months (1-6). Median baseline CEC levels were 67 cells/ml, with an increase of 169.8% after 4 weeks of treatment. Any time CEC levels in patients with a TTP lower than 4 months were higher, but not statistically significant, compared with those in patients with TTP more than 4 months.

Conclusion

Treatment with sorafenib changed CEC levels in HCC patients.

Down-regulation of microRNA-338-3p promoted angiogenesis in hepatocellular carcinoma

miRNAs are involved in substantial biological passways, including tumorigenesis, cancer development and progression. Angiogenesis plays a vital role in the progression of hepatocellular carcinoma (HCC), and VEGF is closely associated with the angiogenesis. However, the molecular mechanism of miRNAs in regulation tumorigenesis of HCC remains to be investigated. In the present research, we confirmed that miR-338-3p was suppressed both in HCC tissues and HCC cell lines. Then the tube formation, transwell and Chorioallantoic membrane (CAM) assay were carried out, such indicated that down-regulation of miR-338-3p can sharply increased, while up-regulation drastically suppressed angiogenesis of HCC cells in vitro. Moreover, MACC1 is predicted to be a target of miR-338-3p and we checked the prediction through luciferase assay. And then, our research showed that negative correlation existed between miR-338-3p and MACC1, β-catenin and VEGF that has been reported participated in cancer behavior in HCC cell lines. Subsequently, our assays illustrated that suppression miR-338-3p can up-regulate MACC1, β-catenin and VEGF expression of HCC cells. In conclusion, our research discovered that miR-338-3p can contribute to HCC angiogenesis by targeting MACC1, β-catenin and VEGF.

Prognostic significance of neutrophil to lymphocyte ratio in patients with gallbladder carcinoma

BACKGROUND

Numerous literature suggest that the preoperative neutrophil to lymphocyte ratio (NLR) is correlated to the prognosis of various cancers. However, the prognostic significance of NLR in gallbladder carcinoma (GBC) remains to be determined.

METHODS

Data from 316 GBC patients with surgical treatment were reviewed retrospectively. A receiver operating characteristic (ROC) curve was performed to determine an optimal cut-off value for NLR. The Kaplan-Meier method and Cox regression proportional hazard model were performed to evaluate prognostic factors.

RESULTS

The optimal cut-off point for NLR was 2.61 according to the ROC curve. According to the univariable analysis, NLR, differentiation and TNM stage were associated with GBC prognosis. GBC patients with NLR > 2.61 have worsened 5-year overall survival (OS) compared to patients with NLR ≤ 2.61 (P < 0.001). Multiple analyses indicated that NLR (hazard ratio (HR) 1.65; 95 percent confidence interval (95% CI) 1.25-2.17), differentiation (HR 1.25; 95% CI 0.97-1.62) and TNM stage (HR 3.79; 95% CI 2.09-6.87) were independent prognostic factors for GBC. GBC patients in stage III/IV, NLR > 2.61 exhibited worse OS compared to patients with NLR ≤ 2.61 (P < 0.05). A prognostic evaluation model based on the independent prognostic factors was established.

CONCLUSION

NLR is associated with GBC prognosis and is a potential prognostic marker for GBC, not only preoperatively but also postoperatively.

Significance and therapeutic implications of endothelial progenitor cells in angiogenic-mediated tumour metastasis

Cancer conveys profound social and economic consequences throughout the world. Metastasis is responsible for approximately 90% of cancer-associated mortality and, when it occurs, cancer becomes almost incurable. During metastatic dissemination, cancer cells pass through a series of complex steps including the establishment of tumour-associated angiogenesis. The human endothelial progenitor cells (hEPCs) are a cell population derived from the bone marrow which are required for endothelial tubulogenesis and neovascularization. They also express abundant inflammatory cytokines and paracrine angiogenic factors. Clinically hEPCs are highly correlated with relapse, disease progression, metastasis and treatment response in malignancies such as breast cancer, ovarian cancer and non-small-cell lung carcinoma. It has become evident that the hEPCs are involved in the angiogenesis-required progression and metastasis of tumours. However, it is not clear in what way the signalling pathways, controlling the normal cellular function of human BM-derived EPCs, are hijacked by aggressive tumour cells to facilitate tumour metastasis. In addition, the actual roles of hEPCs in tumour angiogenesis-mediated metastasis are not well characterised. In this paper we reviewed the clinical relevance of the hEPCs with cancer diagnosis, progression and prognosis. We further summarised the effects of tumour microenvironment on the hEPCs and underlying mechanisms. We also hypothesized the roles of altered hEPCs in tumour angiogenesis and metastasis. We hope this review may enhance our understanding of the interaction between hEPCs and tumour cells thus aiding the development of cellular-targeted anti-tumour therapies.

Expression of the potential cancer stem cell markers CD133 and CD44 in medullary thyroid carcinoma: A ten-year follow-up and prognostic analysis

BACKGROUND AND OBJECTIVES

To investigate the expression profiles of cancer stem cells (CSCs) markers CD133 and CD44 in a cohort of medullary thyroid carcinoma (MTC) patients, and their prognostic values during 10-year follow-up.

METHODS

MTC samples were obtained for H&E and immunohistochemical analysis. Survival analysis was performed using Kaplan-Meier method and log-rank test.

RESULTS

Both the CD133 and CD44 positives were higher in MTC than control. High expression of CD133 and CD44 was positively correlated with capsule invasion and each other, and their co-expression was significantly correlated with capsule invasion, tissue invasion, and metastases at surgery. Tumor size, capsular invasion, tissue invasion, metastases at surgery, surgical plan, lymph node metastases, TNM stage, CD133, and CD44 were prognostic factors for overall survival (OS) and/or disease free survival (DFS). Both the CD133 and CD44 were unfavorable prognostic predictors for OS (P = 0.046, P = 0.03), while only CD44 was a significant predictor for DFS (P = 0.017). OS rate in CD133/CD44 co-expression group was significantly lower than that in non-co-expression group (χ(2)  = 8.44, P = 0.004).

CONCLUSION

Our study suggested the high expression of CD133 and CD44 in the MTC, and CD133 and CD44 expressions were correlated with capsule invasion and with OS. CD133 and/or CD44 may be prognostic factors for OS and/or DFS in our MTC patients.

Endothelial progenitors promote hepatocarcinoma intrahepatic metastasis through monocyte chemotactic protein-1 induction of microRNA-21

OBJECTIVES

Endothelial progenitor cells (EPCs) circulate with increased numbers in the peripheral blood of patients with highly-vascularised hepatocellular carcinoma (HCC) and contribute to angiogenesis and neovascularisation. We hypothesised that angiogenic EPCs, that is, colony forming unit-endothelial cells (CFU-ECs), and outgrowth EPCs, that is, endothelial colony-forming cells, may exert paracrine effects on the behaviours and metastatic capacities of human hepatoma cells.

DESIGN

Various molecular and functional approaches ranging from in vitro cell culture studies on molecular signalling to in vivo investigations on cell invasion and orthotropic transplantation models in mice and clinical specimens from patients with HCC were used.

RESULTS

Monocyte chemotactic protein-1 (MCP-1) was identified as a critical mediator released from CFU-ECs to contribute to the chemotaxis of Huh7 and Hep3B cells by inducing their microRNA-21 (miR-21) biogenesis through the C-C chemokine receptor-2/c-Jun N-terminal kinase/activator protein-1 signalling cascade. CFU-EC-induction of miR-21 in these cells activated their Rac1 and matrix metallopeptidase-9 by silencing Rho GTPase-activating protein-24 and tissue inhibitor of metalloproteinase-3, respectively, leading to increased cell mobility. MCP-1-induction of miR-21 induced epithelial-mesenchymal transformation of Huh7 cells in vitro and their intrahepatic metastatic capability in vivo. Moreover, increased numbers of MCP-1(+) EPCs and their positive correlations with miR-21 induction and metastatic stages in human HCC were found.

CONCLUSIONS

Our results provide new insights into the complexity of EPC-HCC interactions and indicate that anticancer therapies targeting either the MCP-1 released from angiogenic EPCs or the miR-21 biogenesis in HCC cells may prevent the malignant progression of primary tumours.

Circulating endothelial progenitor cell: a promising biomarker in clinical oncology

Human cancers are endowed with sustained vascularization capability, and their growth, invasion, and metastasis are vascularization dependent. Recently, accumulated body of evidence suggests that endothelial progenitor cells (EPCs) can support vasculogenesis and induce angiogenesis through paracrine mechanisms. In addition, numerous clinical studies have revealed the increase in the number of EPCs in the peripheral blood of cancer patients and demonstrated the correlation of circulating EPCs (CEPCs) with the clinical outcomes. This review highlights current enrichment procedures and methods for the detection of CEPCs and different biomarkers to identify CEPCs as well as the functions of EPCs in tumor vascularization. Furthermore, we systematically review available studies on the clinical relevance of CEPCs in cancer patients to explore the potential diagnostic and prognostic values of CEPCs. Although several contrasting results exist, CEPCs can conceivably serve as a promising biomarker for the early diagnosis, prognosis prediction, and treatment response indication in the future. Additionally, further well-designed clinical studies with larger sample size and unique, specific enumeration procedures are warranted to achieve further insight into the clinical implications of CEPCs.

Endothelial progenitor cells--potential new avenues to improve neoangiogenesis and reendothelialization

The term endothelial progenitor cell (EPC) was established more than 10 years ago and is used to refer to a group of circulating cells that display endothelial lineage qualities and are able to home to areas of ischemia or vascular injury and to facilitate the repair of damaged blood vessels or develop new vessels as needed. This chapter reviews the current lineage relationships among all the cells called EPC and will clear the terminology used in EPC research. Furthermore, an overview of the clinical and in vitro research, as well as cytokine and drug interactions and potential EPC applications, is given.

Preoperative neutrophil-to-lymphocyte ratio is a predictor of recurrence following thermal ablation for recurrent hepatocellular carcinoma: a retrospective analysis

PURPOSE

The aim of this study is to determine the predictive value of preoperative blood neutrophil-to-lymphocyte ratio (NLR) for recurrence in recurrent hepatocellular carcinoma (RHCC) patients following thermal ablation.

MATERIAL AND METHODS

This retrospective study enrolled 506 RHCC patients who underwent thermal ablation from April 2006 to April 2014. The clinicopathological parameters including NLR were evaluated to identify predictors of recurrence rate after thermal ablation. A Cox multiple regression analysis was performed to determine the parameters that predicted recurrence in RHCC patients. The best cutoff value of NLR was determined with time-dependent receiver operating characteristic (ROC) curve analysis. The recurrence-free survival (RFS) rate was determined in patients with high and low NLR.

RESULTS

The multivariate Cox proportional hazard model analysis showed that NLR was a prognostic factor in recurrence-free survival. NLR ≥ 2.14 was evaluated (AUROC = 0.824; P<0.001), and 183 of 506 patients (36.2%) had a NLR of more than 2.14. During the follow-up period (12-96 months), the 1-, and 3- year recurrence rates were 20.7% and 31.6% in low NLR group, respectively. These recurrence rates were significantly less than those in the high NLR group (57.9% and 82.5%, respectively) (P<0.001). A recurrence-free survival analyses demonstrated that the RFS in the low NLR group (67.2%) was significantly higher than that in the high NLR group (13.1%) (P<0.001).

CONCLUSION

Our results show that preoperative NLR is a predictor for re-recurrence after thermal ablation in RHCC patients. Additionally, patients with NLR <2.14 have a lower recurrence rate, which may improve the clinical management of RHCC patients.

Identification and significance of mobilized endothelial progenitor cells in tumor neovascularization of renal cell carcinoma

Neovascularization is a key role of renal cell carcinoma (RCC) and the status of neovascularization in RCC is closely correlated with the tumor development and patient prognosis. Endothelial progenitor cells (EPCs) are considered as important building blocks for neovascularization. However, the role of mobilized EPCs in RCC remains unknown. In this study, the orthotopic RCC model was established to investigate the distribution, frequency, and significance of mobilized EPCs. We found that circulating endothelial progenitor cell (CEPC) levels and plasma angiogenic factors (vascular endothelial growth factor (VEGF) and stromal cell-derived factor-1 (SDF-1) were higher in peripheral blood (PB) of the RCC than those in the normal group and positively correlated with each other. EPC levels in adjacent nonmalignant kidney tissue (AT) were significantly higher than those in tumor tissue (TT) and normal kidney tissue (NT), which were positively correlated with CEPC levels. VEGF, VEGF receptor-2 (Flk), and SDF-1 and its SDF-1 receptor (CXCR4) expression in AT was significantly higher than that in TT and NT. Levels of these angiogenic factors in AT were positively correlated with those in PB. Mean microvessel density (MVD) was higher in AT than in TT, and that in TT was slightly lower than that in NT. Our findings propose that mobilized EPCs play an important role in RCC neovascularization. EPCs in PB and AT can be used as a biomarker for predicting RCC progression.

GGPPS1 predicts the biological character of hepatocellular carcinoma in patients with cirrhosis

Background

Hepatocellular carcinoma (HCC) has been associated with diabetes and obesity, but a possible connection with the metabolic syndrome (MetS) and its potential interaction with hepatitis and cirrhosis are open to discussion. Our previous investigations have shown that GGPPS1 plays a critical role during hyperinsulinism. In this report, the expression and distribution of GGPPS1 in liver cancer, and its clinical significance were investigated.

Methods

70 patients with hepatocellular carcinoma (HCC) were included in this study. Three different types of tissues from each HCC patient were assembled immediately after surgical resection: tumor-free tissue >5 cm far from tumor edge (TF), adjacent nonmalignant tissue within 2 cm (AT), and tissue from the tumor (TT). Normal liver tissues from 10 liver transplant donors served as healthy control (HC) while 10 patients with liver cirrhosis as cirrhosis control (CC). The expression and distribution of GGPPS1 were detected by immunohistochemistry, western blots, or real-time PCR. The relationship between the expression of GGPPS1 and clinic pathologic index were analyzed.

Results

We found that GGPPS1 was intensified mainly in the cytoplasm of liver tumor cells. Both the expression of GGPPS1 mRNA and protein were upregulated in TT comparing to AT or TF. Meanwhile, HCC patients with cirrhosis had relative higher expression of GGPPS1. In addition, many pathologic characters show close correlation with GGPPS1, such as tumor stage, vessel invasion, and early recurrence.

Conclusion

GGPPS1 may play a critical role during the development of HCC from cirrhosis and is of clinical significance for predicting biological character of HCC.

CD133-targeted niche-dependent therapy in cancer: a multipronged approach

Cancer treatment continues to be challenged by the development of therapeutic resistances and relapses in the clinical setting, which are largely attributed to tumor heterogeneity, particularly the existence of cancer stem cells (CSCs). Thus, targeting the CSC subpopulation may represent an effective therapeutic strategy. However, despite advances in identifying and characterizing CD133(+) CSCs in various human cancers, efforts to translate these experimental findings to clinical modalities have been slow in the making, especially in light of the growing awareness of CSC plasticity and the foreseeable pitfall of therapeutically targeting CSC base sorely on a surface marker. We, and others, have demonstrated that the CD133(+) CSCs reside in complex vascular niches, where reciprocal signaling between the CD133(+) CSCs and their microenvironment may govern niche morphogenesis and homeostasis. Herein, we discuss the multifaceted functional role of the CD133(+) cells in the context of their niche, and the potential of targeting CD133 as a niche-dependent approach in effective therapy.

Angiogenesis in liver regeneration and fibrosis: "a double-edged sword"

Angiogenesis, defined as the formation of new microvasculature from preexisting blood vessels and mature endothelial cells, plays a major role in wound healing and scar formation, and it is associated with inflammatory responses. Angiogenesis can occur in physiological conditions, such as during liver regeneration, and in pathological situations, such as during the progression of fibrosis to cirrhosis and also during tumor angiogenesis. Cellular cross-talk among liver sinusoidal endothelial cells (LSECs), hepatic stellate cells and hepatocytes is believed to play an important role in the angiogenesis process during both liver regeneration and development of cirrhosis. In addition to mature endothelial cells, bone marrow (BM)-derived circulating endothelial progenitor cells (EPCs) have been recently identified for their contribution to post-natal vasculogenesis/angiogenesis. In vivo, EPCs are mobilized into the peripheral blood in response to tissue ischemia or traumatic injury, migrate to the sites of injured endothelium and differentiate into mature endothelial cells. In our recent studies, we have explored the role of EPC-mediated angiogenesis in liver regeneration and/or cirrhosis. Results have demonstrated significantly increased endogenous levels of circulating EPCs in cirrhotic patients in comparison to the controls. Also, EPCs from cirrhotic patients have been observed to stimulate substantial angiogenesis by resident LSECs in vitro via paracrine factors such as vascular endothelial growth factor and platelet-derived growth factor. This review gives an overview of the angiogenesis process in liver regeneration and disease and discusses a new mechanism for intrahepatic angiogenesis mediated by BM-derived EPCs.

Endothelial progenitor cells: current issues on characterization and challenging clinical applications

Since their discovery about a decade ago, endothelial precursor cells (EPC) have been subjected to intensive investigation. The vision to stimulate respectively suppress a key player of vasculogenesis opened a plethora of clinical applications. However, as research opened deeper insights into EPC biology, the enthusiasm of the pioneer era has been damped in favour of a more critical view. Recent research is focused on three major questions: The fact that the number of EPC in peripheral blood is exceedingly low has consistently raised suspicion whether these cells can plausibly have an impact on physiological or pathophysiological processes. Secondly, whereas the key role of EPC in tumourigenesis has been strongly emphasized by various groups in the past, recent publications are challenging this hypothesis. Thirdly, the lack of consensus on EPC-defining markers and standardized protocols for their detection have repeatedly led to difficulties concerning comparability between papers. In this current review, an overview on recent findings on EPC biology is given, their challenging clinical implications are discussed and the perplexity underlying the current controversial debate is illustrated.

Increased number and function of endothelial progenitor cells stimulate angiogenesis by resident liver sinusoidal endothelial cells (SECs) in cirrhosis through paracrine factors

BACKGROUND & AIMS

Recent studies have shown a pathological role of angiogenesis in the progression of chronic liver diseases (CLDs). The present study focused on numbers and angiogenic functions of circulating endothelial progenitor cells (EPCs) in patients with cirrhosis.

METHODS

Circulating EPCs were counted by flow-cytometry, and correlated with different parameters of liver disease. They were cultured in patients and controls to compare colony-formation, proliferation and tube formation. Interactions of EPCs with hepatic stellate cells (HSCs) and sinusoidal endothelial cells (SECs) were examined by indirect and direct co-cultures in presence of EPCs and EPC-conditioned medium, respectively. ELISA and inhibition assays were performed to assess the role of EPC-derived angiogenic factors.

RESULTS

The number of circulating EPCs was substantially higher in cirrhotic patients compared to controls (p<0.05), and showed good correlation with hepatic disease severity. Functional assays revealed that colonies and proliferation of EPCs were significantly increased in patients compared to controls (p<0.05). Direct and indirect co-cultures of patients' EPCs showed an increase in tube formation by SECs as compared to that observed with control EPCs (p<0.05). There was, however, no tube formation in HSC-EPC co-cultures. Levels of PDGF-BB and VEGF were substantially increased in patients' EPC media and inhibition of these factors by neutralizing antibodies led to a significant reduction in SECs proliferation.

CONCLUSIONS

Mobilization and proliferation of EPCs are significantly enhanced in cirrhotic patients in comparison to controls. EPCs may play an important paracrine role in liver angiogenesis by stimulating resident SECs in cirrhosis.

Intravenous administration of endothelial progenitor cells transfected with the TRAIL gene inhibits the growth of tumors derived from H22 cells in nude mice

AIM: To investigate the influence of intravenous administration of endothelial progenitor cells (EPCs) transfected with the TRAIL gene on the growth of tumors derived from subcutaneously inoculated H22 cells in nude mice to provide a theoretical basis for the treatment of liver cancer.

METHODS: The TRAIL gene was amplified by PCR, cloned into the pcDNA3.1 vector, and transfected into EPCs. The expression of TRAIL protein was detected by Western blot. Mice were inoculated subcutaneously with H22 cells to induce tumor formation. Tumor-bearing mice were randomly divided into three groups and injected via the tail vein with EPCs transfected with the recombinant adenoviral vector carrying the TRAIL gene, the empty vector, and normal saline, respectively.

RESULTS: Restriction enzyme digestion and DNA sequencing analyses indicate that the recombinant plasmid was constructed successfully. TRAIL expression was detected in EPCs transfected with the recombinant adenoviral vector by Western blot. The rate of reduced tumor growth was 47.77% in mice administered with EPCs carrying the TRAIL gene. Tumor volume and weight in the experimental group (0.791 cm3 ± 0.119 cm3, 0.29 g ± 0.04 g) were significantly lower than those in the two control groups (all P < 0.05).

CONCLUSION: The recombinant plasmid carrying the TRAIL gene has been successfully constructed. Intravenous administration of endothelial progenitor cells transfected with the TRAIL gene inhibits the growth of tumors derived from H22 cells in nude mice.

Endothelial progenitor cells homing to the orthotopic implanted liver tumor of nude mice

This study investigated the "homing" phenomenon in hepatocellular carcinoma (HCC). The "homing" specificity of endothelial progenitor cells (EPC) by establishing an orthotopic implantation model in nude mice. EPCs harvested from the marrow cells were separated by density gradient centrifugation. Fluorescence microscope, flow cytometry (FCM) and double fluorescence staining with FITC-UEA-I and DiI-ac-LDL, were employed to identify the cells. 4',6-diamidino-2-phenylindole (DAPI) labelling and real-time PCR were used for detecting the expression of CD133 and chemokines to trace and observe the distribution of EPCs. Our results showed that the distribution rate of EPCs was obviously higher than that in other important organs and the negative control group. Detection of CD133 and chemokines yielded similar results in difference tissues. Our experiment confirmed that the chemotaxis of EPCs does exist in HCC. Moreover, HIF-1α, SDF-1 and VEGF might play important roles in the "homing" of EPCs in HCC. EPCs might be a potential candidate for targeting vector of HCC for gene therapy.

Endothelial precursor cells promote angiogenesis in hepatocellular carcinoma

AIM: To investigate the role of bone marrow-derived endothelial progenitor cells (EPCs) in the angiogenesis of hepatocellular carcinoma (HCC).

METHODS: The bone marrow of HCC mice was reconstructed by transplanting green fluorescent protein (GFP) + bone marrow cells. The concentration of circulating EPCs was determined by colony-forming assays and fluorescence-activated cell sorting. Serum and tissue levels of vascular endothelial growth factor (VEGF) and colony-stimulating factor (CSF) were quantified by enzyme-linked immunosorbent assay. The distribution of EPCs in tumor and tumor-free tissues was detected by immunohistochemistry and real-time polymerase chain reaction. The incorporation of EPCs into hepatic vessels was examined by immunofluorescence and immunohistochemistry. The proportion of EPCs in vessels was then calculated.

RESULTS: The HCC model was successful established. The flow cytometry analysis showed the mean percentage of CD133CD34 and CD133VEGFR2 double positive cells in HCC mice was 0.45% ± 0.16% and 0.20% ± 0.09% respectively. These values are much higher than in the sham-operation group (0.11% ± 0.13%, 0.05% ± 0.11%, n = 9) at 14 d after modeling. At 21 d, the mean percentage of circulating CD133CD34 and CD133VEGFR2 cells is 0.23% ± 0.19%, 0.25% ± 0.15% in HCC model vs 0.05% ± 0.04%, 0.12% ± 0.11% in control. Compared to the transient increase observed in controls, the higher level of circulating EPCs were induced by HCC. In addition, the level of serum VEGF and CSF increased gradually in HCC, reaching its peak 14 d after modeling, then slowly decreased. Consecutive sections stained for the CD133 and CD34 antigens showed that the CD133+ and CD34+ VEGFR2 cells were mostly recruited to HCC tissue and concentrated in tumor microvessels. Under fluorescence microscopy, the bone-marrow (BM)-derived cells labeled with GFP were concentrated in the same area. The relative levels of CD133 and CD34 gene expression were elevated in tumors, around 5.0 and 3.8 times that of the tumor free area. In frozen liver sections from HCC mice, cells co-expressing CD133 and VEGFR2 were identified by immunohistochemical staining using anti-CD133 and VEGFR2 antibodies. In tumor tissue, the double-positive cells were incorporated into vessel walls. In immunofluorescent staining. These CD31 and GFP double positive cells are direct evidence that tumor vascular endothelial cells (VECs) come partly from BM-derived EPCs. The proportion of GFP CD31 double positive VECs (out of all VECs) on day 21 was around 35.3% ± 21.2%. This is much higher than the value recorded on day 7 group (17.1% ± 8.9%). The expression of intercellular adhesion molecule 1, vascular adhesion molecule 1, and VEGF was higher in tumor areas than in tumor-free tissues.

CONCLUSION: Mobilized EPCs were found to participate in tumor vasculogenesis of HCC. Inhibiting EPC mobilization or recruitment to tumor tissue may be an efficient strategy for treating HCC.

The mobilization, recruitment and contribution of bone marrow-derived endothelial progenitor cells to the tumor neovascularization occur at an early stage and throughout the entire process of hepatocellular carcinoma growth

Obvious neovascularization is a key feature of hepatocellular carcinoma (HCC) and the status of neovascularization in HCC is closely correlated with the tumor growth and patient prognosis. The actual effect of current antivascular treatment including embolization to HCC is not satisfactory. Compensatory angiogenesis is one of the primary causes responsible for failure of antiangiogenic therapy. Bone marrow-derived endothelial progenitor cells (BM-EPCs) are considered as important building blocks for adult neovascularization. However, the role of mobilized BM-EPCs in HCC remains unknown. In this study, GFP+-BM orthotropic HCC mice were established to investigate whether BM-EPCs are involved in HCC-induced neovascularization. We found that a large number of BM-EPCs were mobilized into the circulation with the development of HCC, recruited into the HCC region and incorporated into the vascular endothelium directly by differentiation into vascular endothelial cells, including sinus, capillary vessels and great vessels. Dynamic observation revealed that the mobilization and the incorporation of BM-EPCs into different types of vessels were present in early phases and throughout the whole process of HCC growth. The proportion of BM-EPCs in vessels increased gradually, from 17 to 21% with tumor growth. Moreover, injected GFP+-EPCs also specifically homed to tumor tissue and incorporated into tumor vessels directly. In this initial study, we demonstrated that BM-EPCs play a prominent role in HCC neovascularization. Blockade of BM-EPC-mediated vasculogenesis may improve the efficacy of current anti-vascularization therapy for patients with HCC.

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.

Bone marrow cells: Important role on neovascularization of hepatocellular carcinoma

BACKGROUND AND AIM

Present antivascular therapies including embolization to hepatocellular carcinoma (HCC) were not as satisfying as expected. The aim was to explore whether or not bone marrow cells (BMCs) played an important role on neovascularization in HCC.

METHODS

Bone marrow-GFP(+) orthotropic HCC mice model was used. In controls and HCC mice, the dynamic change of circulating BMCs and serum vascular endothelial growth factor (VEGF), platelet derived growth factor (PDGF) were measured by flow cytometry and enzyme linked immunosorbent assay, respectively. Intrahepatic distribution of BMCs was evaluated using immunofluorescent and realtime polymerase chain reaction protocols. BMCs' intrahepatic differentiation and proportion in vessels was investigated by immunofluorescent methods. Immunohistochemistry and western blotting were performed to examine the expression of adhesion molecule in tumor tissues and tumor free tissues.

RESULTS

Compared with controls, the frequency of circulating BMCs and serum VEGF, PDGF were much higher in HCC mice. The number of BMCs and the level of CD133 gene in tumor increased significantly relative to the tumor free zone. Since the early stage of HCC, BMCs have been mobilized, recruited into tumor and incorporated into different types of vessels of the liver. Besides into endothelial cells, BMCs also differentiated into vascular fibroblast and hepatic stellate cells. Moreover with tumor growth, the proportion of BMCs in vessels increased gradually.

CONCLUSION

Mobilized BMCs played an important role in tumor vasculogenesis of HCC. Combined blockading of bone marrow-mediated vasculogenesis may improve the efficacy of current therapy to HCC patients.

FTY720 suppresses liver tumor metastasis by reducing the population of circulating endothelial progenitor cells

BACKGROUND

Surgical procedures such as liver resection and liver transplantation are the first-line treatments for hepatocellular carcinoma (HCC) patients. However, the high incidence of tumor recurrence and metastasis after liver surgery remains a major problem. Recent studies have shown that hepatic ischemia-reperfusion (I/R) injury and endothelial progenitor cells (EPCs) contribute to tumor growth and metastasis. We aim to investigate the mechanism of FTY720, which was originally applied as an immunomodulator, on suppression of liver tumor metastasis after liver resection and partial hepatic I/R injury.

METHODOLOGY/PRINCIPAL FINDINGS

An orthotopic liver tumor model in Buffalo rat was established using the hepatocellular carcinoma cell line McA-RH7777. Two weeks after orthotopic liver tumor implantation, the rats underwent liver resection for tumor-bearing lobe and partial hepatic I/R injury. FTY720 (2 mg/kg) was administered through the inferior caval vein before and after I/R injury. Blood samples were taken at days 0, 1, 3, 7, 14, 21 and 28 for detection of circulating EPCs (CD133+CD34+). Our results showed that intrahepatic and lung metastases were significantly inhibited together with less tumor angiogenesis by FTY720 treatment. The number of circulating EPCs was also significantly decreased by FTY720 treatment from day 7 to day 28. Hepatic gene expressions of CXCL10, VEGF, CXCR3, CXCR4 induced by hepatic I/R injury were down-regulated in the treatment group.

CONCLUSIONS/SIGNIFICANCE

FTY720 suppressed liver tumor metastasis after liver resection marred by hepatic I/R injury in a rat liver tumor model by attenuating hepatic I/R injury and reducing circulating EPCs.

Modulation of chemotactic and pro-inflammatory activities of endothelial progenitor cells by hepatocellular carcinoma

Endothelial progenitor cells (EPCs) participate in the neovascularization processes in the development of hepatocellular carcinoma (HCC). We investigated whether interactions between EPCs and HCC cells affect chemotactic and pro-inflammatory activities of EPCs. Two distinct phenotypes of circulating EPCs, i.e., myeloid-derived EPCs (colony forming unit-endothelial cells, CFU-ECs) and outgrowth EPCs (endothelial-colony forming cells, ECFCs), were co-cultured with Huh7 and Hep3B cells by using transwell chamber and IBIDI(TM) Culture-Inserts and μ-slide plates. Transwell and horizontal migration/invasion assays and time-lapse microscopy were used to monitor and analyze the migration and invasion of EPCs induced by these HCC cells. A human cytokine antibody array was used to compare protein expression profiles in EPCs and HCC cells. Flow cytometry and electromobility shift analysis were used to detect nuclear factor-κB (NF-κB)-DNA binding activity and pro-inflammatory adhesion molecule expression in EPCs. Ectopic full-length CC chemokine receptor 6 (CCR6) plasmid was used to transfect into ECFCs to investigate the role of CCR6 in HCC-induced EPC migration and invasion. The results show that co-culture with Huh7 and Hep3B cells induces the expression of endothelial cell (EC) markers KDR, Flt1, CD31 and VE-cadherin in CFU-ECs, but down-regulates the expressions of CD31 and VE-cadherin in ECFCs. These HCC cells induce migration and invasion of CFU-ECs, but not ECFCs, and do not affect the cell cycle distribution in these EPCs. Cytokine protein array identifies macrophage inflammatory protein-3α (MIP-3α) produced by HCC cells as a critical factor responsible for the HCC-induced chemotaxis of CFU-ECs, which highly express the specific MIP-3α counterreceptor CCR6. Overexpressing CCR6 in ECFCs significantly increases their chemotaxis in response to HCC cells. Co-culturing EPCs with HCC cells results in decreases in NF-κB binding activity and hence intracellular adhesion molecule-1, vascular cell adhesion molecule-1, and E-selectin expressions in EPCs. Our results indicate that HCC cells exert differential effects on CFU-ECs and ECFCs, with increased chemotaxis for CFU-ECs, but not ECFCs. This HCC-induced chemotaxis of CFU-ECs is mediated by MIP-3α produced by HCC cells, which targets to CCR6 on CFU-ECs. Tumors may provide a humoral microenvironment to attenuate the pro-inflammatory activity of EPCs, which might be associated with the tumor escape mechanism.

A scoring model based on neutrophil to lymphocyte ratio predicts recurrence of HBV-associated hepatocellular carcinoma after liver transplantation

BACKGROUND

Neutrophil to lymphocyte ratio (NLR) has been proposed to predict prognosis of hepatocellular carcinoma (HCC). However, the cut-off values are empirical. We determined the optimal cut-off value to predict HCC recurrence after liver transplantation (LT) and further established a scoring model based on NLR.

METHODOLOGY/PRINCIPAL FINDINGS

We analyzed the outcome of 101 HBV-associated HCC patients undergoing LT. Preoperative risk factors for tumor recurrence were evaluated by univariate analysis. By using ROC analysis, NLR≥3 was considered elevated. The disease-free survival (DFS) and overall survival (OS) for patients with high NLR was significantly worse than that for patients with normal NLR (the 5-year DFS and OS of 28.5% and 19.5% vs. 64.9% and 61.8%, respectively; P<0.001). Univariate analysis revealed that tumor size >5 cm, tumor number >3, macrovascular invasion, AFP≥400 µg/L, NLR≥3, and HBV-DNA level >5 log10 copies/mL were preoperative predictors of DFS. Cox regression analysis showed macrovascular invasion, tumor number, and high NLR were independent prognostic factors. We then established a preoperative prognostic score based on multivariate analysis. Each factor was given a score of 1. Area under the ROC curve of the score was 0.781. All nine patients with score 3 developed recurrence within 6 months after LT. Of 71 patients without vascular invasion, three patients with both tumor number >3 and NLR≥3 developed recurrence within 14 months after LT while the 5-year DFS and OS for patients with a score of 0 or 1 were 68.1% and 62.8%, respectively.

CONCLUSIONS/SIGNIFICANCE

Preoperative elevated NLR significantly increases the risk of recurrence in patients underwent LT for HCC. Patients with both NLR≥3 and tumor number >3 are not a good indication for LT. Our score model may aid in the selection of patients that would most benefit from transplantation for HCC.

Endothelial progenitor cells: a novel tool for the therapy of ischemic diseases

Circulating endothelial progenitor cells (EPCs) are believed to home to sites of neovascularization, contributing to vascular regeneration either directly via incorporation into newly forming vascular structures or indirectly via the secretion of pro-angiogenic growth factors, thereby enhancing the overall vascular and hemodynamic recovery of ischemic tissues. The therapeutic application of EPCs has been shown to be effective in animal models of ischemia, and we as well as other groups involved in clinical trials have demonstrated that the use of EPCs was safe and feasible for the treatment of critical limb ischemia and cardiovascular diseases. However, many issues in the field of EPC biology, especially in regard to the proper and unambiguous molecular characterization of these cells, still remain unresolved, hampering not only basic research but also the effective therapeutic use and widespread application of these cells. Further, recent evidence suggests that several diseases and pathological conditions are correlated with a reduction in the number and biological activity of EPCs, making the development of novel strategies to overcome the current limitations and shortcomings of this promising but still limited therapeutic tool by refinement and improvement of EPC purification, expansion, and administration techniques, a rather pressing issue.

CXCR2-Dependent Endothelial Progenitor Cell Mobilization in Pancreatic Cancer Growth

Neovascularization is essential for tumor growth. We have previously reported that the chemokine receptor CXCR2 is an important regulator in tumor angiogenesis. Here we report that the mobilization of bone marrow (BM)-derived endothelial progenitor cells (EPCs) is impaired in CXCR2 knockout mice harboring pancreatic cancers. The circulating levels of EPCs (positive for CD34, CD117, CD133, or CD146) are decreased in the bone marrow and/or blood of tumor-bearing CXCR2 knockout mice. CXCR2 gene knockout reduced BM-derived EPC proliferation, differentiation, and vasculogenesis in vitro. EPCs double positive for CD34 and CD133 increased tumor angiogenesis and pancreatic cancer growth in vivo. In addition, CD133(+) and CD146(+) EPCs in human pancreatic cancer are increased compared with normal pancreas tissue. These findings indicate a role of BM-derived EPC in pancreatic cancer growth and provide a cellular mechanism for CXCR2 mediated tumor neovascularization.

Pilot study to relate clinical outcome in pancreatic carcinoma and angiogenic plasma factors/circulating mature/progenitor endothelial cells: Preliminary results

Circulating endothelial cells (CEC) and bone marrow-derived endothelial progenitors (ECP) play important roles in tumor growth and have been proposed as non-invasive markers of angiogenesis. However, CEC and ECP levels have not been investigated in pancreatic carcinoma patients. Using four-color flow cytometry procedures, we evaluated the count of resting (rCEC) and activated (aCEC) endothelial cells and ECP in the peripheral blood of pancreatic carcinoma patients before and after chemotherapy, consisting of gemcitabine (GEM) alone or in combination with oxaliplatin (OX), or with 5-fluorouracil (5-FU). We also correlated CEC and ECP levels with plasma levels of relevant angiogenic factors, such as vascular endothelial growth factor (VEGF)-A, VEGF-D, angiopoietin (Angio)-1, and chemokine C-X-C motif ligand (CXCL)12, measured by ELISA, and with clinical features of pancreatic cancer. The aCEC, rCEC, ECP, and VEGF-A plasma levels were significantly higher in locally-advanced and metastatic patients than controls. Both ECP and VEGF-A levels correlated positively with disease stage and inversely with patient's overall survival. Measurements after the treatment course showed that VEGF-A plasma concentrations and ECP counts had decreased significantly. In particular, VEGF-A and rCEC were significantly down after treatment with GEM alone or in combination with OX. No significant differences in terms of circulating angiogenic factor or endothelial cell subtype levels were found between responders (patients entering partial remission or with stable disease) and non-responders (patients with progressive disease). The study provides insights into angiogenesis mechanisms in pancreatic carcinoma, for which anti-angiogenic targeting of VEGF-A and ECP could be of interest.

Mechanism of endothelial progenitor cell recruitment into neo-vessels in adjacent non-tumor tissues in hepatocellular carcinoma

Background

We investigated the distribution and clinical significance of mobilized endothelial progenitor cells (EPCs) in hepatocellular carcinoma (HCC). We found that many more EPCs were recruited to nonmalignant liver tissue (especially into adjacent non-tumor tissues (AT)) than to tumor vessels. These results suggest that the mechanism underlying the recruitment of EPCs into microvessels in AT merits further investigation

Methods

Angiogenic factors were detected in three tissue microarrays comprising normal liver, paired tumor tissue (TT) and AT from 105 patients (who had undergone hepatectomy for HCC) using immunohistochemistry. Also, the number of EPCs (positive for Sca-1, Flk-1 and c-Kit) in the blood and liver of cirrhotic mice were determined by flow cytometry and immunohistochemistry. The distribution of these labeled EPCs in tumor and non-tumor tissues was then studied.

Results

The results from the tissue microarrays showed that the expression levels of VEGF-A, bFGF, TGF-β, MCP-1, TSP-1, MMP-9, TIMP-2, and endostatin were significantly higher in AT than in either normal liver or TT (p < 0.05), but no significant difference was found in the expression levels of COX-2 and NOS-2 between AT and TT. The expression of VEGF-A, bFGF, TGF-β, MCP-1, TSP-1, MMP-9, TIMP-2, endostatin, COX-2, and NOS-2 in normal liver tissue was weaker than that in AT or TT. In cirrhotic mice, the number of circulating endothelial progenitor cells gradually increased, before decreasing again. In this mouse model, increased numbers of EPCs were recruited and homed specifically to the cirrhotic liver.

Conclusions

Both liver cirrhosis and HCC led to increased expression of pro-angiogenic factors, which resulted in the recruitment of EPCs into AT. Also, EPCs were mobilized, recruited and homed to cirrhotic liver. The unique pathology of HCC coupled with liver cirrhosis may, therefore, be associated with the distribution and function of EPCs.