Correlation of adrenomedullin with the erythropoietin receptor and microvessel density in hepatocellular carcinoma

Introduction

Uncontrolled angiogenesis plays an essential role in the occurrence, metastasis and malignant progression of hepatocellular carcinoma (HCC). This study aimed to investigate the expression of adrenomedullin (ADM) in human HCC and its correlation with the expression of erythropoietin receptor (EPOR), microvessel density (MVD) and the tumor pathological characteristics.

Material and methods

Fresh tumor tissues were obtained from 30 HCC patients after hepatectomy. Ten cirrhotic and 10 normal liver tissues were included as controls. Expression of ADM and EPOR was determined by real-time PCR. The MVD was determined by counting the number of microvessels.

Results

The MVD and the mRNA levels of ADM and EPOR in cancer tissues were significantly higher than those in the non-cancer tissues (p < 0.05). Expression of ADM was significantly correlated with the MVD and EPOR (r = 0.68 and 0.74, p < 0.01). Adrenomedullin and EPOR mRNA levels in HCC tissues were correlated with capsule invasion, pathological differentiation and tumor metastasis (p < 0.05).

Conclusions

Our findings suggest that ADM and EPOR may serve as new regulatory factors involved in angiogenesis of HCC and represent novel targets for the treatment of HCC.     

Erythropoietin/erythropoietin-receptor system is involved in angiogenesis in human hepatocellular carcinoma

AIMS: To correlate microvascular density and erythropoietin (Epo)/Epo-receptor (EpoR) expression in endothelial and tumour cells with histopathological type in hepatocellular carcinoma (HCC). Methods AND RESULTS: Specimens of primary HCC obtained from 50 patients who had undergone curative hepatectomy were investigated immunohistochemically by using anti-CD31, anti-Epo and anti-EpoR antibodies. Poorly differentiated HCC had a higher degree of vascularization than other stages and Epo/EpoR expression in both tumour and endothelial cells increased in parallel with grade of malignancy and was highly correlated with the extent of angiogenesis. CONCLUSIONS: Epo/EpoR levels correlate with angiogenesis and progression of patients with HCC and these findings suggest the presence of a loop in the Epo/EpoR system, i.e. Epo is secreted by hepatic tumour cells and it affects vascular endothelial cells via its receptors and promotes angiogenesis in a paracrine manner. It is thus suggested that Epo is an important factor in hepatic tumour angiogenesis. Understanding the mechanisms of HCC angiogenesis provides a basis for a rational approach to the development of antiangiogenic therapy in patients with hepatic cancer.     

Increased expression of miR-21 predicts poor prognosis in patients with hepatocellular carcinoma

Background: MicroRNAs (miRNAs) play critical roles in hepatocellular carcinoma (HCC) development and progression. Aberrant miR-21 expression has been reported in several cancers. However, the clinical significance of miR-21 in human HCC is still unclear. Methods: A total of 112 patients with primary HCC who underwent a curative liver resection were included in this retrospective study. The differentially expressed amount of the miR-21 was validated by quantitative real-time PCR (qRT-PCR). Survival rate was analyzed by log-rank test, and survival curves were plotted according to Kaplan-Meier. Multivariate analysis of the prognostic factors was performed with Cox regression model. Results: As revealed by qRT-PCR analysis, miR-21 expression was significantly upregulated in HCC tissues when compared with adjacent non-tumor tissues (P<0.05). High miR-21 expression level was observed to be closely correlated with tumor differentiation, TNM stage and vein invasion (P<0.05). Patients who had high miR-21 expression had a shorter overall survival than patients who had low miR-21 expression (P<0.05). Moreover, multivariate analysis of the prognosis factors with a Cox proportional hazards model showed that high miR-21 expression was a significant independent predictor of poor survival in HCC (P<0.05). Conclusion: Our results suggested that increased expression of miR-21 was significantly correlated with tumor progression and could be a novel potential biomarker for HCC prognosis.     

肝细胞肝癌中LOXL2过表达与转移及预后的相关性

目的检测LOXL2和上皮-间质转化(epithelial-mesenchymal transition,EMT)相关基因在肝细胞肝癌组织中的表达,揭示LOXL2和EMT之间的关系,从而阐明LOXL2对肝细胞肝癌转移及预后的影响。方法采用免疫组化法检测106例肝细胞肝癌组织中LOXL2、Snail、E-cadherin和vimentin的表达,采用CD31/PAS双染法检测肝细胞肝癌中血管生成拟态(vasculogenic mimicry,VM)的情况,并分析LOXL2与EMT分子之间的相关性。采用χ~2和Spearman相关分析来分析其与VM形成和临床病理资料之间的关系。采用Kaplan-Meier法评估LOXL2对肝细胞肝癌患者生存时间的影响。采用Cox比例风险模型分析LOXL2对肝细胞肝癌预后的价值。结果 LOXL2表达与Snail、vimentin和E-cadherin的表达密切相关,LOXL2表达与肿瘤分级和VM形成相关。LOXL2阳性表达或VM形成的患者其总体生存期和无病生存期比LOXL2阴性表达和无VM形成的患者短(P0.05);同时具有LOXL2阳性表达和VM形成的患者预后最差。结论 LOXL2表达与EMT标记蛋白相关,并与肝细胞肝癌分级和VM形成密切相关,且对预后有一定的影响。     

Association of Notch1 with vasculogenic mimicry in human hepatocellular carcinoma cell lines

Background and aims: According to recent findings, some tumor cells function as endothelial progenitor cells to initiate tumor vasculogenesis, known as “vasculogenic mimicry” (VM). Notch1, the key regulator of vasculogenesis and embryonic differentiation, has shown a correlation with a poor prognosis in hepatocellular carcinoma (HCC). We attempted to elucidate the relationship between Notch1 and the vascularization of HCC. Materials and methods: HCC cell lines were assayed for tube formation and low-density lipoprotein (LDL) absorption. The translation level of targets of interest was verified using western blot. Notch1 was silenced in HepG2, BEL-7402 and HCCLM6 using lentivirus shRNA. A hypoxic culture was conducted in an anaerobic culture chamber to induce VM in HepG2. Samples from 53 patients with HCC, i.e., 5 with metastasis and 48 without were tested for Notch1⁺ cells and CD34 negative plus Periodic Acid-Schiff (PAS) positive structures, respectively. Results: BEL-7402 and HCCLM6 were capable of tube formation and LDL absorption in vitro, while HepG2 was negative for both. Notch1 down-regulation suppressed endothelial marker expression and greatly impaired tube formation. After hypoxic culture, the tube formation capacity of HepG2 was significantly enhanced, along with an increase in Notch1 expression. Notch1 was strongly and profusely expressed in all 5 cases of distant metastasis, while 19 of the 48 cases without metastasis were sparsely positive (P < 0.05). Notch1 positivity was mainly seen in the cytoplasm and nuclei. VM structures were only found in 2 cases from the metastasis group (P < 0.05). Conclusions: HCC is capable of VM. Notch1 might serve as a potential target for VM development in HCC.     

肝细胞癌微循环模式的形态及分布

目的:探讨肝细胞癌中微循环模式的形态结构与分布特点.方法:采用CD34-PAS双重染色法对87例肝细胞癌标本进行染色,判定各种微循环模式组织学结构特点并量化各种微循环模式的分布.结果:肝细胞癌中存在CD34-PAS染色双阳性的内皮细胞依赖性血管,其是血液供应的主要模式;35.63％的病例存在血管生成拟态,且出现肿瘤细胞型和细胞外基质型2种组织学类型;32.18％的病例组织中出现马赛克血管;肿瘤细胞型血管生成拟态、细胞外基质型血管生成拟态和马赛克血管的供血面积之和占全部的36.22％.结论:肝细胞癌组织至少存在4种微循环模式且具有异质性.     

High-level expression of HOXB13 is closely associated with tumor angiogenesis and poor prognosis of hepatocellular carcinoma

Homeobox B13 (HOXB13) is generally considered as a crucial regulator of terminal cellular differentiation. More recently, the absent or aberrant expression of HOXB13 has been increasingly implicated in cancer development and metastasis. However, the expression of HOXB13 in hepatocellular carcinoma (HCC) and its correlation with tumor angiogenesis and prognosis still remain unclear. The aim of the study was to evaluate the expression of HOXB13 in patients with HCC and explore the relationship of HOXB13 expression with clinicopathologic factors, tumor angiogenesis and prognosis. Immunohistochemistry was performed to determine the expression of HOXB13 in HCC and corresponding paracarcinomatous tissues from 72 patients. Vascular endothelial growth factor (VEGF) and CD31 were only examined in tissues of HCC patients mentioned above. The results showed that HOXB13 expression was significantly (P <0.001) higher in HCC (69.4%) than that in surrounding non-tumor tissues (26.4%), positively correlated with tumor VEGF (P <0.001) and microvessel density (MVD) (P = 0.013). Besides, it was associated with tumor capsula (P <0.001), vascular invasion (P <0.001), Edmondson grade (P <0.001), AFP (P = 0.007) and TNM stage (P <0.001). Univariate analysis showed poorer overall survival (OS) rate and disease free survival (DFS) rate in patients expressing higher levels of HOXB13. HOXB13 was also found to be an independent poor prognostic factor of OS and DFS in multivariate analysis. Taken together, our results suggest that increased HOXB13 expression is associated with tumor angiogenesis and progression in HCC and may function as a promising biomarker for unfavorable prognosis of HCC.     

Erythropoietin/erythropoietin receptor system is involved in angiogenesis in human neuroblastoma

AIMS: Previous studies have shown that increased vascularity is associated with tumour progression in human neuroblastoma (NB). The involvement of erythropoietin (Epo) in tumour angiogenesis has also been reported. The aim of this study was to correlate microvascular density and Epo/Epo-receptor (EpoR) expression in endothelial and tumour cells to the clinical stage of NB. METHODS AND RESULTS: Specimens of NB obtained from 20 patients were investigated immunohistochemically by using anti-CD31, anti-Epo and anti-EpoR antibodies. The extent of angiogenesis was found to be up-regulated in advanced disease. In keeping with this observation, Epo/EpoR expression in tumour and endothelial cells, respectively, was also highly correlated with the extent of angiogenesis and higher clinical stage. CONCLUSIONS: The correlation of Epo/EpoR expression with angiogenesis and tumour progression suggests the presence of a loop in the Epo-EpoR system. Epo is secreted by tumour cells and affects vascular endothelial cells via its receptor, promoting tumour angiogenesis in a paracrine manner. Data suggest that Epo represents an important mediator in NB angiogenesis. Understanding the mechanisms of NB angiogenesis provides the basis for a rational approach to the development of antiangiogenic therapy in patients affected by NB.     

Up-regulation of long non-coding RNA Sox2ot promotes hepatocellular carcinoma cell metastasis and correlates with poor prognosis

Background: Long non-coding RNAs (lncRNAs) have been shown to have important regulatory roles in cancer biology, and the lncRNA Sox2ot is up-regulated in some tumors. However, the contributions of Sox2ot to hepatocellular carcinoma (HCC) remain largely unknown. Methods: In the present study, expression of lncRNA Sox2ot was evaluated by quantitative real-time PCR in tumor tissues and adjacent non-tumor tissues in 84 HCC patients. The association of lncRNA Sox2ot expression with clinicopathological features and the prognosis of HCC patients were also analyzed. Survival analysis was performed using the Kaplan-Meier method and Cox’s proportional hazards model. Small interfering RNA assay was used to explore the function of lncRNA Sox2ot on HCC cell migration and invasion. Results: lncRNA Sox2ot expression level was significantly higher in HCC tissues compared with adjacent non-tumor tissues (P<0.05). High expression of lncRNA Sox2ot was associated with histological grade, TNM stage, and vein invasion. The 5-year overall survival of high lncRNA Sox2ot expression group was significantly shorter than that of low lncRNA Sox2ot expression group (P<0.05). The multivariate Cox regression analysis indicated that lncRNA Sox2ot expression was an independent prognostic factor for overall survival. In addition, the metastasis ability of HCC cells was significantly decreased by knocking down lncRNA Sox2ot expression. Conclusions: The results suggested that lncRNA Sox2ot played crucial roles in promoting HCC cell migration and invasion, and might represent a novel prognostic biomarker for HCC.     

胰岛素生长因子受体-2在肝细胞癌预后判断中的临床价值

目的:探讨胰岛素生长因子受体-2(insulin-like growth factor-2 receptor,IGF-2R)在肝细胞癌(hepatocellular carcinoma,HCC)预后判断中的临床价值.方法:采用免疫组织化学染色(IHC)检测人类肝癌组织中IGF-2R的表达,并分析IGF-2R组织水平与HCC患者临床病理特征之间关系.结果:IHC结果显示IGF-2R主要在HCC细胞的胞质和胞膜中表达,与匹配的癌旁正常组织相比,IGF-2R蛋白水平在HCC组织中更高,差异有统计学意义(P＜0.05),并且与肿瘤分化程度正相关(P=0.012).单变量和多变量生存分析显示TNM分期(HR=9.87,95％CI 4.13～17.80,P=0.008)、门脉癌栓(HR=5.21,95％CI 1.38～10.76,P=0.023)和IGF-2R高表达(HR=2.30,95％CI 1.20～5.01,P=0.033)与HCC患者预后不良相关.结论:这些数据表明IGF-2R表达与HCC患者的总体存活负相关,是潜在的HCC新型分子靶标和预后标志物.     

LOXL4 is downregulated in hepatocellular carcinoma with a favorable prognosis

Lysyl oxidase like 4 (LOXL4), a member of the secreted copper-dependent amine oxidases that contribute to the assemble and maintenance of the extracellular matrix (ECM), was found to be up-regulated or down-regulated in different cancer types, suggesting its paradoxical roles in cancer. The specific role of LOXL4 in hepatocellular carcinoma (HCC), however, is still yet to be defined. Twenty-eight pairs of HCC specimens were used for LOXL4 mRNA expression analysis. The mRNA expression in HCC cell lines was examined, and HepG2 was selected for LOXL4 small interfering RNA (siRNA) interference to investigate the biological function of LOXL4, LOXL4 immunohistochemical staining was performed using a tissue microarray containing 298 HCC patients. The prognostic and diagnostic value of LOXL4 was evaluated using Cox regression and Kaplan-Meier analysis. LOXL4 mRNA or protein expression was significantly lower in HCC tissues than peritumoral tissues (LOXL4 mRNA expression, P = 0.018; LOXL4 protein expression, P < 0.001). Low LOXL4 expression was associated with lower overall survival (OS) rates and higher cumulative recurrence rates. Multivariate analysis indicated that LOXL4 was an independent prognostic indicator for OS and time to recurrence (TTR). Our results revealed that LOXL4 was down-regulated in HCC and correlated with aggressive tumors and a worse clinical outcome. LOXL4 may be a potential biomarker to identify the HCC patients with a higher risk of recurrence.     

Insulin-like growth factor binding protein-1 inhibits cancer cell invasion and is associated with poor prognosis in hepatocellular carcinoma

Insulin-like growth factor binding protein-1 (IGFBP-1) plays an important role in the development and progression of cancer. However, the expression of IGFBP-1 remains equivocal, and little is known about its clinicopathological significance and prognostic value in hepatocellular carcinoma (HCC). In this study, we evaluated the expression of IGFBP-1 in 90 paired HCC tissues and adjacent non-cancerous liver tissues and analyzed its clinical and prognostic significance. The results showed that IGFBP-1 was detected in cytoplasm as well as cell nucleus, and down-regulated in HCC tissues compared to the adjacent non-cancerous liver tissues. The decreased expression of IGFBP-1 was correlated with tumor differentiation, liver cirrhosis, microvascular invasion or metastasis, TNM stage and poor survival. Moreover, low levels of IGFBP-1 may be an independent prognostic indicator for the survival of patients with HCC. We also evaluated its function by adding recombinant IGFBP-1 to the cultured HCC cell lines HepG2 and MHCC97-H. The result of the invasion chamber assay showed that IGFBP-1 could inhibit the invasion of HepG2 and MHCC97-H. MMP-9 secretion by these cells was significantly decreased when the cells were treated with IGFBP-1. Our results suggest that IGFBP-1 inhibits the invasion and metastasis of HCC cells and that IGFBP-1 may be useful as a valuable marker for the prognosis of patients with HCC.     

Erythropoietin and erythropoietin receptor system in a large uterine myoma of a patient with myomatous erythrocytosis syndrome: possible relationship with the pathogenesis of unusual tumor size

The rare condition of women with erythrocytosis and a concurrent myomatous uterus has been classified as "myomatous erythrocytosis syndrome". Substantial myoma size has been noted as a common denominator in this condition in which recent evidence have confirmed erythropoietin (Epo) production by myoma tissues themselves. Apart from its primary endocrine role in controlling erythropoiesis, Epo has been demonstrated to mediate several cellular processes such as angiogenesis, mitogenesis, and inhibition of apoptosis by autocrine and paracrine mechanisms. Recently, Epo and its receptor (Epo-R) have been shown to be involved in the growth, viability, and angiogenesis of several malignant tumors including human female reproductive organ malignancies. In this paper, we researched on Epo and, as a first in the literature, Epo-R immunoexpression in a large uterine myoma of a term pregnant patient suffering from the myomatous erythrocytosis syndrome. Eight nongravidic leiomyomas and 8 gravidic leiomyomas were used as control group samples. Apart from confirming Epo production by myoma smooth muscle cells in the myomatous erythrocytosis syndrome, we reveal in this pathologic condition a characteristic strong Epo-R expression in myoma endothelial cells and a weak and sporadic Epo-R expression in myoma smooth muscle cells. The striking presence of Epo-R within myoma tissues in the case of the myomatous erythrocytosis syndrome allows us to speculate that myoma Epo production, besides determining erythrocytosis through systemic effects, may contribute, acting by autocrine and paracrine mechanisms, in determining the large myoma size almost always observed in this condition. Finally, we confirm a less but specific immunostaining for Epo in uterine myomas of patients without erythrocytosis and, as a first in the literature, we prove a weak and sporadic Epo-R expression in these lesions. These last results may contribute to knowledge of the yet unclear etiopathogenesis of the most common human gynecologic neoplasm.     

Stathmin overexpression cooperates with p53 mutation and osteopontin overexpression, and is associated with tumour progression, early recurrence, and poor prognosis in hepatocellular carcinoma

Stathmin, a major microtubule-depolymerizing protein, is involved in cell cycle progression and cell motility. This study aimed to elucidate its role in the progression, early tumour recurrence (ETR), and prognosis of hepatocellular carcinoma (HCC). Stathmin mRNA was overexpressed in 88/156 (56%) resected, unifocal, primary HCCs, while p53 mutation was present in 72 (46%) and osteopontin mRNA overexpression in 79 (51%). Stathmin mRNA expression exhibited high concordance (93%) with protein expression in 107 cases examined by immunohistochemistry. Stathmin overexpression correlated with high alpha-fetoprotein (>200 ng/ml, p = 0.02), larger tumour size (>5 cm, p = 0.012), high tumour grade (p < 0.0002), high tumour stage (stage IIIA-IV) with vascular invasion and various degrees of intrahepatic metastasis (p < 1 x 10(-8)), ETR (p = 0.003), and lower 5-year survival (p = 0.0007). Stathmin protein expression was often more intense in the peripheral regions of tumour trabeculae, tumour borders, and portal vein tumour thrombi. Stathmin overexpression correlated with p53 mutation (p = 0.017) and osteopontin overexpression (p = 1 x 10(-8)), both of which were associated with vascular invasion (both p < 0.0001) and poorer prognosis (p < 0.0004 and p = 0.0004, respectively). Regardless of the status of p53 mutation or osteopontin expression, stathmin overexpression was associated with higher vascular invasion (all p < 0.0001). Approximately 90% of HCCs harbouring stathmin overexpression with concomitant p53 mutation or osteopontin overexpression exhibited vascular invasion, and hence the lowest 5-year survival, p = 0.00018 and p = 0.0009, respectively. However, we did not find that stathmin overexpression exerted prognostic impact independent of tumour stage. In conclusion, stathmin expression correlates with metastatic potential, is an important prognostic factor for HCC, and may serve as a useful marker to predict ETR.