Qiao Su

Bead‐based microarray analysis of microRNA expression in hepatocellular carcinoma: miR‐338 is downregulated

Aim:  Recent studies have underlined causative links between microRNA (miRNA) deregulation and cancer development. However, the relevance of abnormally expressed miRNA to tumor biology has not been well understood in hepatocellular carcinoma (HCC).

miR-338-3p suppresses invasion of liver cancer cell by targeting smoothened†

MicroRNAs are involved in human carcinogenesis and cancer progression. Our previous study has shown that loss of miR‐338‐3p expression is associated with clinical aggressiveness of hepatocellular carcinoma (HCC). However, the exact roles and mechanisms of miR‐338‐3p remain unknown in HCC. To determine whether and how miR‐338‐3p influences liver cancer cell invasion, we studied miR‐338‐3p in the liver cancer cell lines, and we found that miR‐338‐3p is down‐regulated in treated cells. Forced expression of miR‐338‐3p in SK‐HEP‐1 cells suppressed cell migration and invasion, whereas inhibition of miR‐338‐3p in SMMC‐7721 cells induced cell migration and invasion. Furthermore, smoothened (SMO) was identified as a direct target of miR‐338‐3p. Forced expression of miR‐338‐3p down‐regulated SMO and matrix metalloproteinase (MMP)‐9 expression, but inhibition of miR‐338‐3p up‐regulated SMO and MMP9 expression. However, small interfering RNA targeted SMO reversed the effects induced by blockade of miR‐338‐3p. SMO and MMP9 were overexpressed and associated with invasion and metastasis in HCC tissues. These data indicate that miR‐338‐3p suppresses cell invasion by targeting the smoothened gene in liver cancer in vitro and miR‐338‐3p might be a novel potential strategy for liver cancer treatment. Copyright

Clinical significance of miR-221 and its inverse correlation with p27Kip1 in hepatocellular carcinoma

The aim of the present study is to explore possible role of miR-221 in the pathogenesis of HCC. Matched HCC and adjacent non-cancerous samples were assayed for the expression of miR-221 and three G1/S transition inhibitors: p27Kip1, p21WAF1/Cip1and TGF-β1 by in situ hybridization and immunohistochemistry respectively. p27Kip1 is one of miR-221’s proven targets. Real time qRT-PCR was used to investigate miR-221 and p27Kip1 transcripts in different clinical stages. Western blotting was used to analyze the expression levels of p27Kip1 protein in different clinical stages. In result, miR-221 and TGF-β1 are frequently up-regulated in HCC, while p27Kip1 and p21WAF1/Cip1 proteins are frequently down-regulated. Moreover, miR-221 and p27Kip1’s expression correlated with metastasis and miR-221’s expression also correlated with tumor size. Both of p21WAF1/Cip1and TGF-β1’s expression correlated with tumor differentiations. miR-221’s upregulation and p27Kip1’s downregulation were significantly associated with tumor stages and metastasis. In conclusion, miR-221 is important in tumorigenesis of HCC, possibly by specifically down-regulating p27Kip1, a cell-cycle inhibitor. These results indicate miR-221 as a new therapeutic target in HCC.

Overexpression of YKL-40 is an independent prognostic marker in gastric cancer ☆

YKL-40 is a growth factor for connective tissue cells and a migration factor for endothelial cells. Elevated serum level of YKL-40 has been associated with poor prognosis in many cancers. However, the status of YKL-40 expression and its clinical/prognostic significance in gastric cancer are unclear. In this study, the expression of YKL-40 was studied by immunohistochemistry in gastric cancer tissue microarray containing 172 primary gastric cancer cases and 70 adjacent nonneoplastic mucosa specimens. The correlations between YKL-40 expression and clinicopathologic features, as well as activation of PI3K/Akt pathways were addressed. Expression of YKL-40 was significantly higher in gastric cancer tissues than that in adjacent nonneoplastic tissues. Overexpression YKL-40 was found in 28.4% of gastric cancers and was significantly associated with tumor invasion (P = .007) and lymph node metastasis (P = .009). For survival study, overexpression of YKL-40 was significantly associated with worse outcome (P = .001). When known clinical variables were added to a multivariate analysis, TNM stage, tumor size, and overexpression of YKL-40 emerged as independent prognostic factors. Further study indicated that the oncogenic function of YKL-40 might be through the activation of Akt pathway. These results suggest that overexpression of YKL-40 is correlated with the aggressive behavior of tumor cells, which could be used as an independent molecular marker for the predicting poor prognosis of patients with gastric cancer.

miR‐145 suppresses cell invasion in hepatocellular carcinoma cells: miR‐145 targets ADAM17

miR‐145 is a candidate tumor suppressor miRNA. However, it is unknown whether miR‐145 is involved in the invasion of hepatocellular carcinoma (HCC). Therefore, we aimed to explore the effect and mechanism of miR‐145 in the control of HCC cell invasion.

MicroRNA-129-5p inhibits hepatocellular carcinoma cell metastasis and invasion via targeting ETS1

MiR-129-5p is deregulated in various human cancers and has been associated with hepatocellular carcinoma (HCC) progression. However, the underlying mechanisms of miR-129-5p involvement in the development and progression of HCC and the effects of miR-129-5p deregulation on the clinical characteristics observed in HCC patients remain poorly understood. We therefore investigated the correlation between low miR-129-5p expression and vascular invasion, intrahepatic metastasis, and poor patient survival. Ectopic restoration of miR-129-5p expression in HCC cells suppressed cellular migration and invasion and the expression of v-ets erythroblastosis virus E26 oncogene homolog 1 (ETS1), while inhibition of endogenous miR-129-5p caused an increase in these parameters. We identified the ETS1 gene as a novel direct target of miR-129-5p. SiRNA-mediated ETS1 knockdown rescued the effects of anti-miR-129-5p inhibitor in HCC cell lines, while the effects of miR-129-5p overexpression were partially phenocopied in the knockdown model. In addition, miR-129-5p levels inversely correlated with those of ETS1 in HCC cells and tissues. Taken together, our findings indicate an important role for miR-129-5p in the molecular etiology of invasive HCC and suggest that miR-129-5p could have potential therapeutic applications in HCC.

Expression patterns and polymorphisms of PTCH in Chinese hepatocellular carcinoma patients

Aberrant activation of Hedgehog signaling pathway leads to pathological consequences in a variety of human tumors. PTCH (PTCH1), the receptor of Hedgehog pathway, is reported to function as a gatekeeper in tumor formation. Here we report, by semi-quantitative RT-PCR, PTCH expression was found in 38 hepatocellular carcinoma (HCC) patients (66%). Evidences from real time quantitative RT-PCR further indicate that compared to their matched nontumorous liver tissue, PTCH exhibit a higher expression in well and moderate differentiated tumor, but a lower expression in poorly differentiated tumor. Immunohistochemical staining showed PTCH protein was detected in the cytoplasm of 56.3% HCC samples (9/16). For the first time, we investigate the polymorphisms of PTCH in HCC. First we sequenced the recognized mutation hot spots regions of PTCH of 38 HCC samples. Two previously reported single nucleotide polymorphisms (SNPs) and a novel SNP A1056G were identified. Then we examined these three SNPs in 171 HCC samples and 162 normal liver samples. However, statistic analysis showed none of these SNPs was statistically significant for association with HCC. In conclusion, our data suggest that PTCH is involved in early stage tumor development and the Hh pathway in Chinese HCC is activated by ligand expression but not by mutation.

miR-338-3p inhibits epithelial-mesenchymal transition and metastasis in hepatocellular carcinoma cells

Down-regulation of the miRNA miR-338-3p correlates with the invasive ability of hepatocellular carcinoma (HCC) cells. However, it is currently unclear whether down-regulation of miR-338-3p induces epithelial-mesenchymal transition (EMT), which may be the underlying mechanism governing HCC invasion. Here, we demonstrate that restoration of miR-338-3p expression via transfection of a miR-338-3p mimic reversed EMT and inhibited the motility and invasiveness of HCC cells. Conversely, silencing of endogenous miR-338-3p expression with a miR-338-3p-specific inhibitor induced EMT and enhanced HCC cell motility. Additionally, Snail1 (an upstream regulatory protein of EMT) and Gli1 (a key transcription factor in the sonic hedgehog (SHH) signaling pathway) expression was up-regulated in cells treated with the miR-338-3p inhibitor and down-regulated by the miR-338-3p mimic. Further analyses demonstrated that miR-338-3p inhibitor-induced EMT in HCC cells was blocked by treatment with a small interfering RNA (siRNA) targeting Snail1, that the SHH signaling pathway was required for both miR-338-3p inhibitor-induced EMT and up-regulation of Snail1, and that miR-338-3p targeted a sequence within the 3′-untranslated region of N-cadherin mRNA. Notably, miR-338-3p expression was significantly down-regulated in HCC samples from patients with metastases and was associated with poor metastasis-free survival rates. Lastly, correlations between the expression levels of miR-338-3p and E-cadherin, Smoothened (SMO), Gli1, Snail1, N-cadherin, and vimentin were confirmed in HCC xenograft tumors and HCC patient specimens. Our findings suggest that miR-338-3p suppresses EMT and metastasis via both inhibition of the SHH/Gli1 pathway and direct binding of N-cadherin. miR-338-3p is a potential therapeutic target for metastatic HCC.

Frizzled7 Promotes Epithelial-to-mesenchymal Transition and Stemness Via Activating Canonical Wnt/β-catenin Pathway in Gastric Cancer

Aberrant activation of Wnt signaling is a crucial event in tumor development and metastasis. Wnt signaling is commonly divided into canonical and non-canonical signaling pathways based on whether β-catenin is activated (canonical). The two signaling pathways are initiated by Wnt ligand binding to the surface Frizzled (FZD) receptors, and regulate cancer stem cell self-renewal and epithelial-mesenchymal transition (EMT). Frizzled 7 (FZD7), a member of Frizzled family, promotes cell proliferation and invasiveness in many cancers, suggesting that FZD7 transmitting Wnt signaling is important for driving cancer growth. FZD7 expression has been reported to be up-regulated in human primary gastric cancer tissues. However, the molecular mechanism by which FZD7 promotes gastric cancer(GC) development and progression is not fully understood. Our present study showed that FZD7 was overexpressed in clinical GC samples, and thus was correlated with tumor invasion, lymphatic and organ metastasis, late TNM stages and poor patient survival. The endogenous expression of FZD7 was significantly increased in cancer stem cell-enriched spheres compared with adherent cells. Furthermore, RNA interference-mediated silencing of FZD7 inhibited proliferation, migration and invasion in gastric cancer cells. Moreover, ablation of FZD7 down-regulated EMT and the expression levels of cancer stem cell markers, and these inhibitions were associated with attenuated canonical Wnt/β-catenin signaling. The results suggest that Wnt canonical pathway may contribute to tumorigenesis and metastasis, indicating that FZD7 could be a potential therapeutic target for gastric cancer.

miR-300 regulates the epithelial-mesenchymal transition and invasion of hepatocellular carcinoma by targeting the FAK/PI3K/AKT signaling pathway

Several microRNAs (miRNAs) have been closely correlated with the development of hepatocellular carcinoma (HCC). However, the involvement of miR-300 in the development of HCC remains unknown. This study elucidated the potential molecular mechanisms of miR-300 in the modulation of the epithelial-mesenchymal transition (EMT) and invasion of HCC. The expression levels of miR-300 in HCC cells and clinical samples were detected by quantitative real-time PCR and in situ hybridization. The in vitro function of miR-300 in HCC was evaluated using a migration/invasion assay. Quantitative real-time PCR, western blotting, immunofluorescence and immunohistochemistry were used to validate the roles of miR-300 and FAK/PI3K/AKT in EMT progression. A dual-luciferase reporter assay was performed to confirm the target gene. miR-300 was down-regulated in HCC and significantly correlated with a poor prognosis in HCC patients. The down-regulation of miR-300 increased the invasiveness of the HCC cells, and promoted the EMT in both HCC tissues and HCC cells. In contrast, up-regulation of miR-300 led to the opposite results. Ectopic overexpression of miR-300 reversed TGF-β1-induced EMT in SMMC-7721 cells, and according to a dual-luciferase reporter assay and rescue assay, miR-300 inhibits the EMT-mediated migration and invasion of HCC cells via the targeted modulation of FAK and the downstream PI3K/AKT signaling pathway. miR-300 targeting modulates FAK, and the PI3K/AKT signaling pathway inhibits the EMT and suppresses the migration and invasion of HCC cells. Thus, miR-300 represents a promising therapeutic target for HCC.