Activation of the Notch1-c-myc-VCAM1 signalling axis initiates liver progenitor cell-driven hepatocarcinogenesis and pulmonary metastasis.

The cellular origin of hepatocellular carcinomas (HCC) and the role of Notch1 signalling in HCC initiation are controversial. Herein, we establish Notch1 as a regulator of HCC development and progression. Clinically, high Notch1 expression correlates with enhanced cancer progression, elevated lung metastasis, increased cancer stem cell (CSC)-like cells' gene signature expression, and poor overall survival in HCC patients. Notch1 intracellular domain (N1ICD) overexpression spontaneously transforms rat liver progenitor cells (LPC) into CSC-like cells (WBN1ICD C5) under a selective growth environment, while orthotopic injection of these cells generates liver tumors and spontaneous pulmonary metastasis in an isogenic rat model. Mechanistically, the elevated Notch1 activity increases c-myc expression, which then transcriptionally upregulates VCAM1 expression to activate macrophage dependent HCC transendothelial migration. In vivo, silencing c-myc prohibits the tumorigenicity of WBN1ICD C5 cells, while depletion of VCAM1 reduces spontaneous lung metastasis without affecting primary WBN1ICD C5 orthotopic liver tumor growth. Importantly, depletion of macrophage or blockade of macrophage VCAM1 binding receptor α4ß1-integrin reduces the number of WBN1ICD C5 lung nodules in an experimental metastasis model. Overall, our work discovers that the Notch1-c-myc-VCAM1 signaling axis initiates LPC-driven hepatocarcinogenesis and metastasis, providing a preclinical model for HCC study and therapeutic targets for an improved HCC treatment.

CRLF1-MYH9 Interaction Regulates Proliferation and Metastasis of Papillary Thyroid Carcinoma Through the ERK/ETV4 Axis.

In our previous study, we have shown that CRLF1 can promote proliferation and metastasis of papillary thyroid carcinoma (PTC); however, the mechanism is unclear. Herein, we investigated whether the interaction of CRLF1 and MYH9 regulates proliferation and metastasis of PTC cells via the ERK/ETV4 axis. Immunohistochemistry (IHC), qPCR, and Western blotting assays were performed on PTC cells and normal thyroid cells to profile specific target genes. In vitro assays and in vivo assays were also conducted to examine the molecular mechanism. Results showed that CRLF1 directly bound MYH9 to enhance the stability of CRLF1 protein. Inhibition of MYH9 in PTC cells overexpressing CRLF1 significantly reversed malignant phenotypes, and CRLF1 overexpression activated ERK pathway, in vitro, and in vivo. RNA-sequencing revealed that ETV4 is a downstream target gene of CRLF1, which was up-regulated following ERK activation. Moreover, it was revealed that ETV4 is highly expressed in PTC tissues and is associated with poor prognosis. Finally, the ChIP assays showed that ETV4 induces the expression of matrix metalloproteinase 1 (MMP1) by binding to its promoter on PTC cells. Altogether, our study demonstrates that CRLF1 interacts with MYH9, promoting cell proliferation and metastasis via the ERK/ETV4 axis in PTC.

Methylation-associated silencing of miR-200b facilitates human hepatocellular carcinoma progression by directly targeting BMI1.

This study aims to investigate the biological function of microRNA-200b and BMI1, predicted target of microRNA-200b in human hepatocellular carcinoma (HCC). MicroRNA-200b and BMI1 expression in HCC tissues were evaluated by qPCR. A luciferase reporter assay was used to validate BMI1 as a direct target of microRNA-200b. The effect of microRNA-200b on HCC progression was studied in vitro and in vivo. Methylation specific PCR (MSP) and bisulfite sequencing PCR (BSP) were used to detect the methylation status of the microRNA-200b promoter. Significant downregulation of microRNA-200b was observed in 83.3% of HCC tissues. By contrast, BMI1 was significantly overexpressed in 66.7% of HCC tissues. The results of the luciferase assay confirmed BMI1 as a direct target gene of microRNA-200b. Forced expression of microRNA-200b in HCC cells dramatically repressed proliferation, colony formation, cell cycle progression, and invasion. Moreover, microRNA-200b synergized with 5-fluorouracil to induce apoptosis in vitro and suppressed tumorigenicity in vivo. In addition, MSP analysis and BSP revealed that CpG sites in the promoter region of microRNA-200b were extensively methylated in HCC, with concomitant downregulation of microRNA-200b expression. Furthermore, microRNA-200b was activated in HCC cells after treatment with 5-azacytidine, whereas BMI1 expression was clearly downregulated. Our results indicate that microRNA-200b is partially silenced by DNA hypermethylation and that it can repress tumor progression by directly targeting BMI1 in HCC.

Hepatocellular carcinoma with bile duct tumor thrombus: a clinicopathological analysis of factors predictive of recurrence and outcome after surgery.

Although hepatocellular carcinoma (HCC) with bile duct tumor thrombus (BDTT) is a rare entity, most patients experience tumor recurrence even after curative resection and the prognosis remains dismal. This study aimed to analyze the clinicopathological risk factors for recurrence and poor outcome after surgical treatment of HCC with BDTT.Clinicopathological data of 37 patients with HCC and BDTT who underwent surgical treatment from July 2005 to June 2012 at the authors' hospital were reviewed retrospectively. Prognostic factors and potential risk factors for recurrence were assessed by Cox proportional hazard model and binary logistic regression model, respectively.Among the 37 patients, anatomical and nonanatomical liver resection was performed in 26 and 11 patients, respectively. The resection was considered curative in 19 patients and palliative in 18 patients. Also, 21 cases had tumor recurrence after operation and 7 cases of them were reoperated. Multivariate binary logistic regression model revealed that surgical curability was the only independent risk factor associated with postoperative tumor recurrence (P = 0.034). In addition, postoperative overall survival rates at 1, 2, and 3 years were 64.2%, 38.9%, and 24.3%, respectively. Cox multivariate analysis indicated that surgical curability and tumor recurrence were independent prognostic factors for both overall survival and recurrence-free survival (P < 0.05).Although patients with HCC and BDTT had a relatively high rate of early recurrence after surgery, relatively favorable long-term outcome after curative hepatic resection could be achieved. Therefore, extensive and curative surgical treatment should be recommended when complete resection can be achieved and liver functional reserve is satisfactory.

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.

Role of anti-angiogenesis therapy in the management of hepatocellular carcinoma: The jury is still out.

As the leading cause of disease-related deaths, cancer is a major public health threat worldwide. Surgical resection is still the first-line therapy for patients with early-stage cancers. However, postoperative relapse and metastasis remain the cause of 90% of deaths of patients with solid organ malignancies, including hepatocellular carcinoma (HCC). With the rapid development of molecular biology techniques in recent years, molecularly targeted therapies using monoclonal antibodies, small molecules, and vaccines have become a milestone in cancer therapeutic by significantly improving the survival of cancer patients, and have opened a window of hope for patients with advanced cancer. Hypervascularization is a major characteristic of HCC. It has been reported that anti-angiogenic treatments, which inhibit blood vessel formation, are highly effective for treating HCC. However, the efficacy and safety of anti-angiogenesis therapies remain controversial. Sorafenib is an oral multikinase inhibitor with anti-proliferative and anti-angiogenic effects and is the first molecular target drug approved for the treatment of advanced HCC. While sorafenib has shown promising therapeutic effects, substantial evidence of primary and acquired resistance to sorafenib has been reported. Numerous clinical trials have been conducted to evaluate a large number of molecularly targeted drugs for treating HCC, but most drugs exhibited less efficacy and/or higher toxicity compared to sorafenib. Therefore, understanding the mechanism(s) underlying sorafenib resistance of cancer cells is highlighted for efficiently treating HCC. This concise review aims to provide an overview of anti-angiogenesis therapy in the management of HCC and to discuss the common mechanisms of resistance to anti-angiogenesis therapies.

Notch1 is overexpressed in human intrahepatic cholangiocarcinoma and is associated with its proliferation, invasiveness and sensitivity to 5-fluorouracil in vitro.

The Notch signaling pathway has been reported to play crucial roles in inhibiting hepatocyte differentiation and allowing formation of intrahepatic bile ducts. However, little is known about its significance in intrahepatic cholangiocarcinoma (ICC). The aim of the present study was to investigate the effects of Notch1 expression in ICC tissues and cells. The expression of Notch1 was examined in paraffin-embedded sections of ICC (n=44) by immunohistochemistry. Notch1 was knocked down by RNA interference (RNAi) in cultured ICC cells (RBE and HCCC-9810). The proliferation, invasiveness and sensitivity to 5-fluorouracil (5-FU) were detected by Cell Counting Kit-8 (CCK-8), colony formation assays, Transwell assays and flow cytometry, respectively. The expression levels of several multidrug resistance (MDR)-related genes, MDR1-P-glycoprotein (ABCB­1), breast cancer resistance protein (ABCG­2) and the multidrug resistance protein isoform 1 (MRP­1), were examined by quantitative real-time polymerase chain reaction (qRT-PCR) and western blotting. Notch1 was overexpressed in cell membranes and cytoplasm of ICC compared with the adjacent liver tissue (35/44, 79.5%) and this was more common in cases with tumor size≥5 cm (p=0.021) and HBs-Ag positive (p=0.018). By silencing Notch1, the proliferation and invasiveness of ICC cells were inhibited and the inhibition rate of 5-FU was markedly increased. In addition, IC50 values of 5-FU in RBE cells were decreased from 148.74±0.72 to 5.37±0.28 µg/ml and the corresponding values for HCCC-9810 cells were 326.92±0.87 to 42.60±0.35 µg/ml, respectively. Furthermore, Notch1 silencing clearly increased the percentage of apoptotic cells treated by 5-FU compared with the control. Notch1 knockdown led to diminished expression levels of ABCB­1 and MRP­1. Therefore, Notch may play important roles in the development of ICC. Silencing Notch1 can inhibit the proliferation and invasiveness of ICC cells and increase their sensitivity to 5-FU in vitro.

Clinicopathological significance of aberrant Notch receptors in intrahepatic cholangiocarcinoma.

Notch signaling has been reported to be activated to promote biliary epithelial cell differentiation and tubulogenesis during bile duct development. In this study, clinicopathological significance of aberrant expression of Notch receptors in intrahepatic cholangiocarcinoma (ICC) was investigated. Thus, forty-one ICC specimens were examined by immunohistochemistry using anti-Notch1-4 antibodies, respectively. Expression of Notch receptors was scored by percentage of positive tumor cells and intensity of immunostaining. Clinicopathological parameters and survival data were compared with the expression of Notch receptors, respectively. Expression of Notch receptors was identified in cancer cells, as well as in non-neoplastic cells. Compared with adjacent non-tumor liver tissues, Notch1 and 4 were up regulated, and Notch2 and 3 were relatively weaker. Positive immunostaining of Notch1 in ICC cells was detected in 34 cases (82.9%), Notch2 in 23 (56.1%), Notch3 in 16 (39.0%) and Notch4 in 14 (34.1%). Notch1 was overexpressed in cases with tumor size > 5 cm (P = 0.036). Expression of Notch2 was correlated inversely with histological grade (P = 0.016). Overexpression of Notch4 was more common in cases with serum CA125 > 35 U/ml than cases with CA125 ≤ 35 U/ml (P = 0.048). Expression of Notch3 was not correlated with any other clinicopathological parameters. Moreover, Notch4 was related to poor survival (P < 0.001). To conclude, this study reveals that aberrant expression of Notch receptors 1 and 4 might play important roles during ICC progression.

Over-expression of nerve growth factor-ß in human cholangiocarcinoma QBC939 cells promote tumor progression.

AIMS: It has been shown that nerve growth factor-ß (NGF-ß) promoted the initiation and progression of many tumors, and we have previously demonstrated that the expression of NGF-ß was associated with tumor stage, nerve infiltration and lymph node metastasis in human hilar cholangiocarcinoma. However, whether NGF-ß promotes tumor progression in human cholangiocarcinoma requires further investigation. Therefore, we aimed to determine the effects of NGF-ß on the progression of human cholangiocarcinoma. METHODS: Human cholangiocarcinoma QBC939 stable cell lines with over-expressed or silenced NGF-ß genes were generated with pEGFP-N1-NGF-ß and pGPU6/GFP/Neo-NGF-ß-shRNA recombinant plasmids. Cell proliferation assay, colony formation assay, cell cycle analysis, apoptosis assay and tumorigenicity assay were performed to evaluate the role of NGF-ß in the progression of human cholangiocarcinoma. In addition, human lymphatic endothelial cells were co-cultured with QBC939 culture supernatants, and the cell proliferation and migration abilities of the lymphatic endothelial cells were evaluated. RESULTS: Forced expression of NGF-ß in QBC939 cell lines promoted proliferation, colony formation and tumorigenicity in these cells and inhibited the apoptosis. However, down-regulation of NGF-ß inhibited proliferation, colony formation and tumorigenicity, and increased the apoptotic rate of QBC939 cells. In addition, the NGF-ß gain-of-function induced a high expression of vascular endothelial growth factor C and enhanced the proliferation and migration of lymphatic endothelial cells, while NGF-ß loss-of-function showed opposite effects. CONCLUSIONS: We concluded that NGF-ß promoted tumor progression in human cholangiocarcinoma QBC939 cells. Our results provided a new concept to understand the role of NGF-ß in cholangiocarcinoma progression, and might provide important information for the development of new targeted therapies in human cholangiocarcinoma.