FEN1 promotes cancer progression of cholangiocarcinoma by regulating the Wnt/β-catenin signaling pathway

PURPOSE

Cholangiocarcinoma (CHOL) comprises a cluster of highly heterogeneous malignant biliary tumors. Flap endonuclease-1 (FEN1) is a member of the Rad2 structure-specific nuclease family. This study aimed to explore the biological functions and mechanisms of FEN1 in CHOL.

METHODS

FEN1 expression was analyzed in tissues of patients with CHOL and FEN1 mutations. We observe the influence of FEN1 on cellular proliferation, migration, and invasion, as well as on DNA damage repair and glycolysis. Western blotting was performed to determine the regulatory mechanism of FEN1 in CHOL progression.

RESULTS

FEN1 was highly expressed in the cancer tissues of CHOL patients. The high mutation rate of FEN1 in CHOL tissues was mainly due to the amplified repeats. FEN1 promotes the proliferation, migration, and invasion of HUCCT1 and QBC939 cells. In addition, FEN1 induced DNA damage repair and aerobic glycolysis in CHOL cells. FEN1 also promoted xenograft tumor growth in vivo. Moreover, we showed that FEN1 mediated the epithelial-mesenchymal transition (EMT) of CHOL. FEN1-mediated EMT was found to be transduced by the Wnt/β-catenin signaling pathway.

CONCLUSION

FEN1 was significantly overexpressed in CHOL tissues, and FEN1 regulates the progression of CHOL through the Wnt/β-catenin signaling pathway.

GCNT3 regulated MUC13 to promote the development of hepatocellular carcinoma through the GSK3β/β-catenin pathway

BACKGROUND

Hepatocellular carcinoma (HCC) is a leading cause of cancer-related deaths worldwide. Extensive research is currently directed at identifying novel targets for its diagnosis and treatment.

AIMS

We investigated the biological functions and clinical significance of mucin-type N-acetylglucosaminyltransferase 3 (GCNT3) in HCC.

METHODS

Variations in the mRNA expression of GCNT3 were examined in normal and HCC tissues. Cell function assays and animal models characterized the effects of GCNT3 on the proliferation, invasion, and migration abilities of HCC cells. Western blot and immunofluorescence analyses were performed to explore further the specific mechanisms whereby GCNT3 affects HCC progression.

RESULTS

There is a strong correlation between GCNT3 overexpression and tumor formation and metastasis in vivo and in vitro. GCNT3 acted as a regulator of the synthesis of mucin-type O-glycans by interacting with mucin 13 (MUC13) to regulate its expression levels, activating the GSK3β/β-catenin signaling pathway. The activation of GSK3β/β-catenin signaling by GCNT3 was mitigated by MUC13 knockdown. In clinical HCC specimens, GCNT3 expression was upregulated in HCC tissues compared to non-tumor tissues. Further, there was a significant correlation between high GCNT3 expression and poor patient survival.

CONCLUSIONS

GCNT3 regulated tumor progression in HCC through the MUC13/GSK3-β/β-catenin signaling pathway.

Effect of Microvascular Invasion on the Prognosis in Hepatocellular Carcinoma and Analysis of Related Risk Factors: A Two-Center Study

Objective: Microvascular invasion is considered to initiate intrahepatic metastasis and postoperative recurrence of hepatocellular carcinoma (HCC). We aimed to analyze the effect of MVI on the prognosis in HCC and identify related risk factors for microvascular invasion (MVI).

Methods: The clinical data of 553 HCC patients who underwent liver surgery at Qingdao University from January 2014 to December 2018 and 89 patients at Beijing Tsinghua Changgung Hospital treated between October 2014 and October 2019 were collected retrospectively. We explored the impact of MVI on the prognosis of patients with HCC using Kaplan-Meier analysis. We conducted logistic regression analysis to identify variables significantly related to MVI.

Results: Pathological examination confirmed the presence of MVI in 265 patients (41.3%). Six factors independently correlated with MVI were incorporated into the multivariate logistic regression analysis: Edmondson-Steiner grade [odds ratio (OR) = 3.244, 95%CI: 2.243–4.692; p < 0.001], liver capsule invasion (OR = 1.755; 95%CI: 1.215–2.535; p = 0.003), bile duct tumor thrombi (OR = 20.926; 95%CI: 2.552–171.553; p = 0.005), α-fetoprotein (> 400 vs. < 400 ng/ml; OR = 1.530; 95%CI: 1.017–2.303; p = 0.041), tumor size (OR = 1.095; 95%CI: 1.027–1.166; p = 0.005), and neutrophil-lymphocyte ratio (OR = 1.086; 95%CI: 1.016–1.162; p = 0.015). The area under the receiver operating characteristic curve (AUC) was 0.743 (95%CI: 0.704–0.781; p < 0.001), indicating that our logistic regression model had significant clinical usefulness.

Conclusions: We analyzed the effect of MVI on the prognosis in HCC and evaluated the risk factors for MVI, which could be helpful in making decisions regarding patients with a high risk of recurrence.

Down-Regulation of PDCD4 Promotes Proliferation, Angiogenesis and Tumorigenesis in Glioma Cells

The programmed cell death 4 (PDCD4) tumor-suppressor gene regulates cell apoptosis, protein translation, signal transduction, and induction of mediators of inflammation. However, the mechanism by which PDCD4 is down-regulated and regulates tumor growth remains elusive. In this study, we showed that PDCD4 is down-regulated in glioma cells and acts as a tumor suppressor. Based on the TCGA data, we confirmed that AKT2, but not AKT1 or AKT3, interacts with PDCD4, thus leading to the suppression of PDCD4 in glioma cells. Moreover, the analysis suggested that PDCD4 regulates the expression of IL-5, CCL-5, VEGF, and CXCL10 via the NF-kB pathway. Additionally, depletion of levels of PDCD4 promoted angiogenic activity of glioma cells via the VEGF-STAT3 pathway. When tumor cells over-expressing PDCD4 were injected into nude mice, the increased expression of PDCD4 blocked tumorigenesis and prolonged overall survival. Our study indicates the need to develop drugs that can modulate the expression of PDCD4 and test their efficacy in clinical trials.

Identification of aberrant DNA methylation profiles in non-tumor liver tissues of patients with non-B, non-C hepatocellular carcinoma

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Background: Percentage of patients with non-B non-C (NBNC) hepatocellular carcinoma (HCC) is rapidly increasing in Japan. We have previously shown that miRNA expression profiles in non-tumor liver tissues of patients with NBNC-HCC are different from those of patients with HBV-HCC and HCV-HCC. Moreover, we have recently reported that specific miRNA expression profiles in non-tumor liver tissues can predict a risk of multicentric recurrence after hepatectomy for HCC (Hepatol Res, 2013). In this study, we performed the genome-wide analysis of aberrant DNA methylation in non-tumor liver tissues of patients with NBNC-HCC. Methods: We divided the 23 patients, who underwent hepatectomy, into 3 groups; NBNC (HBcAb-, n=7), NBNC (HBcAb+, n=8), and normal control (NC, n=8). We analyzed DNA methylation status in fresh-frozen non-tumor liver tissues using Infinium Human Methylation 450 Bead Chip (illumina). Gene-expression levels of several identified genes were analyzed by quantitative RT-PCR to validate the correlation between DNA methylation status and gene-expressions. Results: We identified 87 differentially methylated genes in HBcAb- liver tissues, and 603 genes in HBcAb+ liver tissues in comparison to NC liver tissues (Beta value>0.2, P<0.05). Thirty CpG sites were commonly hyper- or hypo-methylated in both HBcAb- and HBcAb+ livers. High percentages of aberrant DNA methylation were observed in gene body. One hypermethylated gene (Lrig1, an intestinal stem cell marker that functions as a tumor suppressor) was confirmed to be down-regulated in its gene-expression level by quantitative RT-PCR. One hypomethylated gene (LEF1, a molecule enhancing hepatocarcinogenesis though Wnt/beta-catenin signaling) was also confirmed to be up-regulated. Ingenuity Pathway Analysisrevealed the association of Wnt/beta-catenin signaling with aberrant DNA methylation status. Conclusions: Genome-wide analysis of aberrant DNA methylation in non-tumor liver tissues may provide not only molecular mechanisms of epigenetic modulation during hepatocarcinogenesis but also early molecular diagnosis in patients with NBNC-HCC.