Effects of Angiotensin II Type 2 Receptor Overexpression on the Growth of Hepatocellular Carcinoma Cells In Vitro and In Vivo

Increasing evidence suggests that the renin-angiotensin system (RAS) plays an important role in tumorigenesis. The interaction between Angiotensin II (AngII) and angiotensin type 1 receptor (AT1R) may have a pivotal role in hepatocellular carcinoma (HCC) and therefore, AT1R blocker and angiotensin I-converting enzyme (ACE) inhibitors may have therapeutic potential in the treatment of hepatic cancer. Although the involvement of AT1R has been well explored, the role of the angiotensin II Type 2 receptor (AT2R) in HCC progression remains poorly understood. Thus, the aim of this study was to explore the effects of AT2R overexpression on HCC cells in vitro and in mouse models of human HCC. An AT2R recombinant adenoviral vector (Ad-G-AT2R-EGFP) was transduced into HCC cell lines and orthotopic tumor grafts. The results indicate that the high dose of Ad-G-AT2R-EGFP–induced overexpression of AT2R in transduced HCC cell lines produced apoptosis. AT2R overexpression in SMMC7721 cells inhibited cell proliferation with a significant reduction of S-phase cells and an enrichment of G1-phase cells through changing expression of CDK4 and cyclinD1. The data also indicate that overexpression of AT2R led to apoptosis via cell death signaling pathway that is dependent on activation of p38 MAPK, pJNK, caspase-8 and caspase-3 and inactivation of pp42/44 MAPK (Erk1/2). Finally, we demonstrated that moderately increasing AT2R expression could increase the growth of HCC tumors and the proliferation of HCC cells in vivo. Our findings suggest that AT2R overexpression regulates proliferation of hepatocellular carcinoma cells in vitro and in vivo, and the precise mechanisms of this phenomenon are yet to be fully determined.     

LncRNA PAPAS promotes hepatocellular carcinoma by interacting with miR-188-5p

It has been observed that long noncoding RNA (lncRNA) PAPAS regulates rRNA synthesis, but its role in human diseases is unclear. Our study was carried out to investigate the role of PAPAS in hepatocellular carcinoma (HCC). In the present study, we found that PAPAS was upregulated both in plasma from patients with HCC and tumors compared with plasma from healthy people and tumor-adjacent healthy tissues. Expression levels of PAPAS in tumor tissues and plasma of patients with HCC were significantly and positively correlated. Plasma levels of PAPAS effectively distinguished stage I patients from healthy controls. MicroRNA (miR)-188-5p was downregulated in tumor tissues than in tumor-adjacent healthy tissues of patients with HCC, and was inversely correlated with PAPAS in tumor tissues but not in adjacent healthy tissues. PAPAS and miR-188-5p downregulated each other. PAPAS overexpression promoted, while miR-188-5p overexpression inhibited the HCC cell proliferation. Rescue experiment showed that miR-34a overexpression attenuated the effects of PAPAS overexpression. However, PAPAS overexpression failed to affect significantly cancer cell migration and invasion. Therefore, lncRNA PAPAS promotes HCC by interacting with miR-188-5p.     

MiR-103 regulates hepatocellular carcinoma growth by targeting AKAP12

AKAP12/Gravin (A kinase anchor protein 12) belongs to the group of A-kinase scaffold proteins and functions as a tumor suppressor in some human primary cancers. While AKAP12 is found consistently downregulated in hepatocellular carcinoma (HCC), its involvement in hepatocarcinogenesis has not been fully elucidated. We identified targeting sites for miR-103 in the 3′-untranslated region (3′-UTR) of AKAP12 by bioinformatic analysis and confirm their function by a luciferase reporter gene assay. We reveal miR-103 expression to be inversely correlated with AKAP12 in HCC tissue samples and show that overexpressed miR-103 promotes cell proliferation and inhibits apoptosis by downregulating AKAP12 expression in HCC cell lines. On the other hand, repression of miR-103 suppresses proliferation and promotes apoptosis in HCC cells by increasing AKAP12. In xenografted HCC tumors, overexpression of AKAP12 suppresses tumor growth whereas overexpression of miR-103 enhances tumor growth while repressing AKAP12. Since the activation of telomerase is crucial for cells to gain immortality and proliferation ability, we investigated whether AKAP12 expression affected telomerase activity in HCC cells. Both AKAP12 overexpression and protein kinase Cα (PKCα) inhibition prevent nuclear translocation and phosphorylation of TERT and reduce telomerase activity in HCC cells. These findings indicate that miR-103 potentially acts as an oncogene in HCC by inhibiting AKAP12 expression and raise the possibility that miR-103 increases telomerase activity by increasing PKCα activity. Thus, miR-103 may represent a new potential diagnostic and therapeutic target for HCC treatment.     

Characterization of bridging integrator 1 (BIN1) as a potential tumor suppressor and prognostic marker in hepatocellular carcinoma

It has been shown that bridging integrator 1 (BIN1) can interact with c-myelocytomatosis (c-Myc) oncoprotein in cancer. However, the role of BIN1 in hepatocellular carcinoma (HCC) is not clear. In the present study, we investigated the expression and prognostic role of BIN1 in primary HCC and evaluated the function of BIN1 in hepatocarcinogenesis. Using real-time polymerase chain reaction and Western blot analysis, we found significantly decreased expression of BIN1 in primary HCC tumor tissues (n = 42) compared with adjacent normal tissues and in HCC cell lines. Immunohistochemistry analysis also found decreased BIN1 expression in HCC tumor tissues (n = 117). In clinicopathological analysis, loss of BIN1 expression correlated significantly (P < 0.05) with differentiation scores and tumor size. Importantly, decreased expression of BIN1 in tumors was found to be closely associated with a poor prognosis, and we conclude that BIN1 was an independent prognostic factor in a multivariate analysis. In mechanistic studies, restoring BIN1 expression in BIN1-null HCC cells significantly inhibited cell proliferation and colony formation and induced apoptosis of HCC cells. Furthermore, we found that BIN1 overexpression could significantly suppress the motility and invasion of HCC cells in vitro. Our results indicate that BIN1 may function as a potential tumor suppressor and serve as a novel prognostic marker in HCC patients. The BIN1 molecule might play an important role in tumor growth, cell motility and invasion. Modulation of BIN1 expression may lead to clinical applications of this critical molecule in the control of hepatocellular carcinoma as well as in early and effective diagnosis of this aggressive tumor.     

DLC-1与肝癌关系研究

DLC-1基因是一种肿瘤抑制基因,位于人类染色体8p21．3-22。它是RhoA特异性GTP酶的激动蛋白,与调控细胞增殖和粘附的信号传导通路关系密切,在人类多种肿瘤中呈低表达或表达缺失。研究发现DLC-1基因在原发性肝癌(HCC)及肝癌细胞系中表达缺失,提示该基因在原发性肝癌中抑制了肝癌细胞的增殖。DLC-1表达的恢复引起了caspase-3介导的细胞凋亡,抑制肝癌细胞的生长和癌细胞的浸润,从而在肝细胞癌的转移、侵袭及肿瘤细胞的生物特性方面发挥作用。因其与肝癌发生,转移乃至复发关系密切,使其在肝癌早期发现,早期预测肝癌的转移复发及肝癌的预后方面发挥重要角色。     

Modulatory efficacy of dieckol on xenobiotic-metabolizing enzymes,cell proliferation,apoptosis, invasion and angiogenesis during NDEA-induced rat hepatocarcinogenesis

Altered microRNA expression is associated with tumor proliferation, metastasis, and tumorigenesis. In this study, we studied the role of miR-3117 in hepatocellular carcinoma (HCC) cell proliferation and found that miR-3117 was upregulated in HCC tissues and cells. MTT assay, soft agar growth assay, BrdU assay, and cell cycle assay revealed that miR-3117 overexpression promoted HCC HepG2 cell proliferation and that knockdown of miR-3117 suppressed HepG2 proliferation. Mechanism analysis suggested PH domain and leucine-rich repeat protein phosphatase-like (PHLPPL) as the target of miR-3117. Luciferase reporter assay suggested that miR-3117 directly binds to the 3′UTR of PHLPPL. Double knockdown of miR-3117 and PHLPPL copied the phenotypes caused by miR-3117 overexpression, suggesting that miR-3117 contributes to the proliferation of HepG2 by targeting PHLPPL. Our study provided a target for HCC therapy.     

Integrin alpha 7 correlates with poor clinical outcomes,and it regulates cell proliferation,apoptosis and stemness via PTK2-PI3K-Akt signaling pathway in hepatocellular carcinoma

This study aimed to evaluate the correlation of integrin alpha 7 (ITGA7) with clinical outcomes and its effect on cell activities as well as stemness in hepatocellular carcinoma (HCC). HCC tumor tissues and paired adjacent tissues from 90 HCC patients were obtained and ITGA7 expression was detected using immunohistochemistry assay. Cellular experiments were conducted to examine the effect of ITGA7 on cell activities, astemness via ITGA7 ShRNA transfection, and compensation experiments were further performed to test whether ITGA7 functioned via regulating PTK2-PI3K-AKT signaling pathway. ITGA7 was overexpressed in tumor tissues compared with paired adjacent tissues and its high expression was correlated with larger tumor size, vein invasion and advanced Barcelona Clinic Liver Cancer stage, and it also independently predicted worse overall survival in HCC patients. In cellular experiments, ITGA7 was upregulated in SMMC-7721, Hep G2, HuH-7 and BEL-7404 cell lines compared with normal human liver cells HL-7702. ITGA7 knockdown suppressed cell proliferation but promoted apoptosis, and it also downregulated CSCs markers (CD44, CD133 and OCT-4) as well as PTK2, PI3K and AKT expressions in SMMC-7721 and Hep G2 cell lines. ITGA7 overexpression promoted cell proliferation but inhibited apoptosis, and it also upregulated CSCs markers in HL-7702 cells. Further compensation experiments verified that ITGA7 regulated cell proliferation, apoptosis and CSCs markers via PTK2-PI3K-Akt signaling pathway. ITGA7 negatively associates with clinical outcomes in HCC patients, and it regulates cell proliferation, apoptosis and CSCs markers via PTK2-PI3K-Akt signaling pathway.     

Silencing GTSE-1 expression inhibits proliferation and invasion of hepatocellular carcinoma cells

G2 and S phase-expressed-1 (GTSE1) was recently reported to upregulate in several types of human cancer, based on negatively regulate p53 expression. However, its expression and functional roles in hepatocellular carcinoma (HCC) remain unknown. In this study, GTSE1 was observed to be highly expressed in HCC specimens and cell lines both at messenger RNA (mRNA) and protein levels. Furthermore, high GTSE1 expression was positively associated with tumor size, venous invasion, advanced tumor stage, and short overall survival. Moreover, we generated stable GTSE1 knockdown HCC cell lines to explore the effects of GTSE1 silencing on the growth and invasion of HCC in vitro. In determining the pathway through which GTSE1 regulated cell proliferation and invasion, GTSE1 silencing was found to inhibit AKT phosphorylation and downregulated cell cycle-related protein. In addition, GTSE1 downregulation decreased the growth of xenografts. In conclusion, these results indicated for the first time that overexpression of GTSE1 was involved in the progress of HCC, enhancing proliferation and promoting cell invasion in HCC cells.     

MicroRNA-144 inhibits hepatocellular carcinoma cell proliferation,invasion and migration by targeting ZFX

MicroRNA 144 (miR-144), a small non-coding RNA, is frequently dysregulated in human several tumour progression, but its role and the underlying mechanisms in hepatocellular carcinoma (HCC) is poorly investigated. In the present study, the expression of miR-144 was firstly analysed in datasets derived from GSE21362 and TCGA, and then detected in HCC tissues and cell lines by quantitative RT-PCR (qRT-PCR) analysis. MiR-144 was shown to be significantly down-regulated in HCC tissues and cell lines. Subsequently, overexpression of miR-144 was transfected into HCC cell lines so as to investigate its biological function, including MTT, colony formation, and transwell assays. Gain of function assay revealed miR-144 remarkably inhibited cell proliferation, migration and invasion. In addition, bioinformatical analysis and luciferase reporter assay identified ZFX as a novel target of miR-144 in HCC cells, as confirmed by qRT-PCR and Western blot. Furthermore, ZFX was found to be significantly up-regulated using Oncomine database analysis. Loss of function assay further indicated knockdown of ZFX had similar effects of miR-144-mediated HCC cell proliferation and invasion. Therefore, miR-144 has been demonstrated to act as a tumour suppressor in HCC cell growth and motility by directly targeting ZFX, which implicates its potential applications in the development of HCC treatment.     

Let-7b contributes to hepatocellular cancer progression through Wnt/β-catenin signaling

Elevated evidences show that microRNAs (miRNAs) play vital roles in tumor progression regulation. However, the functional role of let-7b in hepatocellular carcinoma (HCC) is still largely unknown. In this study, we try to investigate the biological activity of let-7b in human HCC cells and try to find the potential regulatory signaling pathway. Our results indicate that let- 7b was remarkably down-regulated in human HCC tissues by qRT-PCR. In addition, let-7b overexpression decreased the expression of β-catenin and c-Myc, while upregulated E-cadherin expression in HCC cells which was verified by quantitative real-time PCR (qRT-PCR) and western blotting. Furthermore, Wnt/β-catenin was involved in let-7b biological activity which was revealed by luciferase assay. Moreover, Wnt/β-catenin signaling inhibitor blocks HCC cell proliferation which is as the same pattern as let-7b overexpression inhibits in HCC cells proliferation. In conclusion, down-regulated let-7b promotes HCC cell proliferation through Wnt/β-catenin signaling in HCC cells. These results suggested that appropriate manipulation of let-7b might be a new treatment of human HCC in the future.     

Numb Promotes Cell Proliferation and Correlates with Poor Prognosis in Hepatocellular Carcinoma

Background

Numb is an evolutionary conserved protein that plays critical roles in cell fate determination, cell adhesion, cell migration and a number of signaling pathways, but evidence for a substantial involvement of Numb in HCC has remained unclear. The present study was aimed to investigate the clinical and prognostic significance of Numb and its role in hepatocellular carcinoma (HCC).

Methodology

The expression of Numb was detected in 107 cases of clinical paraffin-embedded hepatocellular carcinoma tissues,5 matched paris of fresh tissues and six hepatocellular cell lines by immunohistochemistry with clinicopathological analyses,RT-PCR or Western blot. Moreover, loss of function and gain of function assays were performed to evaluate the effect of Numb on cell proliferation in vitro.

Conclusions

We found that Numb was obviously up-regulated in HCC tissues and cell lines (p<0.05). The Numb up-regulation correlated significantly with poor prognosis, and Numb status was identified as an independent prognostic factor. Over-expression of Numb increased proliferation in SMMC-7721 and BEL-7402 cells, while knock-down of Numb showed the opposite effect. Our study indicates that Numb up-regulation significantly correlates with cell proliferation and poor prognosis in hepatocellular carcinoma patients. It may be a useful biomarker for therapeutic strategy in hepatocellular carcinoma treatment.     

Tumor Suppressive Function of p21-activated Kinase 6 in Hepatocellular Carcinoma

Our previous studies identified the oncogenic role of p21-activated kinase 1 (PAK1) in hepatocellular carcinoma (HCC) and renal cell carcinoma (RCC). Contrarily, PAK6 was found to predict a favorable prognosis in RCC patients. Nevertheless, the ambiguous tumor suppressive function of PAK6 in hepatocarcinogenesis remains obscure. Herein, decreased PAK6 expression was found to be associated with tumor node metastasis stage progression and unfavorable overall survival in HCC patients. Additionally, overexpression and silence of PAK6 experiments showed that PAK6 inhibited xenografted tumor growth in vivo, and restricted cell proliferation, colony formation, migration, and invasion and promoted cell apoptosis and anoikis in vitro. Moreover, overexpression of kinase dead and nuclear localization signal deletion mutants of PAK6 experiments indicated the tumor suppressive function of PAK6 was partially dependent on its kinase activity and nuclear translocation. Furthermore, gain or loss of function in polycomb repressive complex 2 (PRC2) components, including EZH2, SUZ12, and EED, elucidated epigenetic control of H3K27me3-arbitrated PAK6 down-regulation in hepatoma cells. More importantly, negative correlation between PAK6 and EZH2 expression was observed in hepatoma tissues from HCC patients. These data identified the tumor suppressive role and potential underlying mechanism of PAK6 in hepatocarcinogenesis.     

Overexpression of RhoGDI,a novel predictor of distant metastasis,promotes cell proliferation and migration in hepatocellular carcinoma

RhoGDI (Rho GDP-dissociation inhibitor alpha, or RhoGDIα) was identified as a regulator of Rho GTPases, but its role in cancer remains controversial. In this study, increased expression of RhoGDI was detected in hepatocellular carcinoma (HCC) cell lines and tissues with highly metastatic potential. RhoGDI overexpression correlated with postoperative distant metastasis. Enforced expression of RhoGDI in HCC cells significantly enhanced cell proliferation and migration. Conversely, knockdown of RhoGDI caused an inhibition of the aggressive phenotypes of HCC cells. Furthermore, RhoGDI up-regulated Rho, but not Rac, and enhanced PI3K/AKT and MAPK pathway activity. Our findings suggest that RhoGDI overexpression is a predictor of distant metastasis and plays an important role in the progression of HCC.     

Deubiquitinase USP39 and E3 ligase TRIM26 balance the level of ZEB1 ubiquitination and thereby determine the progression of hepatocellular carcinoma

Emerging evidence suggests that USP39 plays an important role in the development of hepatocellular carcinoma (HCC). However, the molecular mechanism by which USP39 promotes HCC progression has not been well defined, especially regarding its putative ubiquitination function. Zinc-finger E-box-binding homeobox 1 (ZEB1) is a crucial inducer of epithelial-to-mesenchymal transition (EMT) to promote tumor proliferation and metastasis, but the regulatory mechanism of ZEB1 stability in HCC remains enigmatic. Here, we reveal that USP39 is highly expressed in human HCC tissues and correlated with poor prognosis. Moreover, USP39 depletion inhibits HCC cell proliferation and metastasis by promoting ZEB1 degradation. Intriguingly, deubiquitinase USP39 has a direct interaction with the E3 ligase TRIM26 identified by co-immunoprecipitation assays and immunofluorescence staining assays. We further demonstrate that TRIM26 is lowly expressed in human HCC tissues and inhibits HCC cell proliferation and migration. TRIM26 promotes the degradation of ZEB1 protein by ubiquitination in HCC. Deubiquitinase USP39 and E3 ligase TRIM26 function in an antagonistic pattern, but not a competitive pattern, and play key roles in controlling ZEB1 stability to determine the HCC progression. In summary, our data reveal a previously unknown mechanism that USP39 and TRIM26 balance the level of ZEB1 ubiquitination and thereby determine HCC cell proliferation and migration. This novel mechanism may provide new approaches to target treatment for inhibiting HCC development by restoring TRIM26 or suppressing USP39 expression in HCC cases with high ZEB1 protein levels.Subject terms: Gene regulation, Prognostic markers     

CDKN2A is a prognostic biomarker and correlated with immune infiltrates in hepatocellular carcinoma

Cyclin dependent kinase inhibitor 2A (CDKN2A) is an essential regulator of immune cell functionality, but the mechanisms whereby it drives immune infiltration in hepatocellular carcinoma (HCC) remain unclear. In the present study, we studied the association with CDKN2A expression and immune invasion with the risk of developing HCC. A totally of 2207 different genes were found between HCC and adjacent liver tissues from TCGA and GEO databases. CDKN2A was highly expressed in HCC and associated with poorer overall survival and disease-free survival. Notably, CDKN2A expression was positively correlated with infiltrating levels into purity, B cell, CD+8 T cell, CD+4 T cell, macrophage, neutrophil, and dendritic cells in HCC. CDKN2A expression showed strong correlations between diverse immune marker sets in HCC. These findings suggest that CDKN2A expression potentially contributes to regulation of tumor-associated macrophages and can be used as a prognostic biomarker for determining prognosis and immune infiltration in HCC.