Yingmin Yao

Fbxw7 is an independent prognostic marker and induces apoptosis and growth arrest by regulating YAP abundance in hepatocellular carcinoma

BackgroundThe E3 ubiquitin ligase Fbxw7 functions as a general tumor suppressor by targeting several well-known oncoproteins for ubiquitination and proteasomal degradation. However, the clinical significance of Fbxw7 and the mechanisms involved in the anti-cancer effect of Fbxw7 in HCC are not clear.MethodThe Fbxw7 and YAP expression in 60 samples of surgical resected HCC and matched normal tumor-adjacent tissues were assessed using IHC or immunoblotting. Flow cytometry, caspase 3/7 activity assay, BrdU cell proliferation assay and MTT assay were used to detect proliferation and apoptosis of HCC cells. The regulatory effect of Fbxw7 on YAP in HCC cells was confirmed by qRT-PCR, immunoblotting and immunofluorescence. Co-immunoprecipitation was used to analyze interaction between YAP and Fbxw7. Nude mice subcutaneous injection, Ki-67 staining and TUNEL assay were used to evaluate tumor growth and apoptosis in vivo.ResultsIn this study, we found that Fbxw7 expression was impaired in HCC tissues and loss of Fbxw7 expression was correlated with poor clinicopathological features including large tumor size, venous infiltration, high pathological grading and advanced TNM stage. Additionally, we demonstrated that patients with positive Fbxw7 expression had a better 5-year survival and Fbxw7 was an independent factor for predicting the prognosis of HCC patients. We confirmed that Fbxw7 inhibited HCC by inducing both apoptosis and growth arrest. Elevated YAP expression was observed in the same cohort of HCC tissues. Pearsons correlation coefficient analysis indicated that Fbxw7 was inversely associated with YAP protein expression in HCC tissues. We also found that Fbxw7 regulated YAP protein abundance by targeting YAP for ubiquitination and proteasomal degradation in HCC. Furthermore, restoring YAP expression partially abrogated Fbxw7 induced HCC cell apoptosis and growth arrest in vitro and in vivo.ConclusionThese results indicate that Fbxw7 may serve as a prognostic marker and that YAP may be a potential target of Fbxw7 in HCC.

Knockdown of MACC1 expression suppressed hepatocellular carcinoma cell migration and invasion and inhibited expression of MMP2 and MMP9

Expression of MACC1 (metastasis-associated in colon cancer-1) protein is associated with metastasis of various human cancers. This study analyzed MACC1 protein expression in hepatocellular carcinoma (HCC) tissue specimens and then investigated the effects of MACC1 knockdown on HCC cell migration and invasion, and gene expression levels. Sixty pairs of HCC and adjacent normal liver tissues from HCC patients were analyzed for MACC1 expression immunohistochemically. The HCC cell lines Hep3B, Huh7, MHCC97H, SMMC-7721, Bel-7402, and HepG2 and the normal liver cell line LO2 were used to assess expressions of MACC1 mRNA and MACC1 protein using qRT-PCR and western blot, respectively. MACC1 short hairpin RNA (shRNA) was used to knockdown MACC1 protein expression in Huh7 cells. Changes in the tumor phenotype of these cells were analyzed with wound healing assay and invasion assays, and differences in gene expression were evaluated via western blot. Immunofluorescence was used to locate MACC1 protein in the above cell lines. MACC1 was highly expressed in HCC tissues and the nuclear expression of MACC1 protein was associated with poor tumor differentiation and intrahepatic metastasis or portal invasion. Moreover, MACC1 mRNA and MACC1 protein was also expressed in HCC cell lines. Immunostaining showed that MACC1 protein was localized in both nuclei and cytoplasm of HCC cell lines and the nuclear localization of MACC1 protein was associated with increased aggressiveness of HCC in cell lines. Knockdown of MACC1 expression using MACC1-shRNA reduced Huh7 cell migration and invasion abilities, which was associated with downregulation of MMP2, MMP9, and c-Met proteins in Huh7 cells. Localization of MACC1 protein to the nucleus may predict HCC progression. Knockdown of MACC1 expression using MACC1 shRNA warrants further evaluation as a novel therapeutic strategy for control of HCC.

Evaluation of Fbxw7 expression and its correlation with the expression of c-Myc, cyclin E and p53 in human hepatocellular carcinoma.

Aim:  F‐box and WD repeat domain‐containing 7 (Fbxw7) is a cell cycle regulatory gene that targets for ubiquitination and proteasomal degradation various cell cycle regulators such as c‐Myc and cyclin E. Defects in the Fbxw7 gene that lead to cell cycle re‐entry and expedite the G1‐S transition is thought to be one of the causes of cancer development. However, its expression and clinical importance for hepatocellular carcinoma (HCC) patients remains undetermined. This prompted us to investigate its expression level in HCC patients to establish its clinical significance.

Recombinant Human Adenovirus-p53 Injection Induced Apoptosis in Hepatocellular Carcinoma Cell Lines Mediated by p53-Fbxw7 Pathway, Which Controls c-Myc and Cyclin E

F-box and WD repeat domain-containing 7 (Fbxw7/hAgo/hCdc4/Fbw7) is a p53-dependent tumor suppressor and leads to ubiquitination-mediated suppression of several oncoproteins including c-Myc, cyclin E, Notch, c-Jun and others. Our previous study has indicated that low expression of Fbxw7 was negatively correlated with c-Myc, cyclin E and mutant-p53 in hepatocellular carcinoma (HCC) tissues. But the role and mechanisms of Fbxw7 in HCC are still unknown. Here, we investigated the function of Fbxw7 in HCC cell lines and the anti-tumor activity of recombinant human adenovirus-p53 injection (rAd-p53, Gendicine) administration in vitro and in vivo. Fbxw7-specific siRNA enhanced expression of c-Myc and cyclin E proteins and increased proliferation in cell culture. rAd-p53 inhibited tumor cell growth with Fbxw7 upregulation and c-Myc and cyclin E downregulation in vitro and a murine HCC model. This effect could be partially reverted using Fbxw7-specific siRNA. Here, we suggest that the activation of Fbxw7 by adenoviral delivery of p53 leads to increased proteasomal degradation of c-Myc and cyclin E enabling growth arrest and apoptosis. Addressing this pathway, we identified that rAd-p53 could be a potential therapeutic agent for HCC.

MicroRNA-130b Promotes Cell Aggressiveness by Inhibiting Peroxisome Proliferator-Activated Receptor Gamma in Human Hepatocellular Carcinoma

MircroRNA-130b (miR-130b) is proposed as a novel tumor-related miRNA and has been found to be significantly dysregulated in tumors. In this study, the expression level of miR-130b was found to be obviously higher in hepatocellular carcinoma (HCC) tissues than that in nontumor tissues. Further, miR-130b was expressed at significantly higher levels in aggressive and recurrent tumor tissues. Clinical analysis indicated that high-expression of miR-130b was prominently correlated with venous infiltration, high Edmondson-Steiner grading and advanced tumor-node-metastasis (TNM) tumor stage in HCC. Elevated miR-130b expression was observed in all HCC cell lines (HepG2, SMMC-7721, Huh7, Hep3B and MHCC97H) as compared with that in a nontransformed hepatic cell line (LO2). Furthermore, an inverse correlation between miR-130b and E-cadherin and a positive correlation between miR-130b and Vimentin were observed in HCC tissues. Down-regulation of miR-130b expression reduced invasion and migration in both Hep3B and MHCC97H cells. Peroxisome proliferator-activated receptor gamma (PPAR-γ) was inversely correlated with miR-130b expression in HCC tissues. In addition, down-regulation of miR-130b restored PPAR-γ expression and subsequently suppressed epithelial-mesenchymal transition (EMT) in HCC cells. We identified PPARγ as a direct target of miR-130b in HCC in vitro. Notably, PPAR-γ knockdown abolished down-regulation of miR-130b-inhibited EMT in MHCC97H cells. In conclusion, miR-130b may promote HCC cell migration and invasion by inhibiting PPAR-γ and subsequently inducing EMT.

SREBP-1 Has a Prognostic Role and Contributes to Invasion and Metastasis in Human Hepatocellular Carcinoma

Sterol regulatory element-binding protein 1 (SREBP-1) is a well-known nuclear transcription factor involved in lipid synthesis. Recent studies have focused on its functions in tumor cell proliferation and apoptosis, but its role in cell migration and invasion, especially in hepatocellular carcinoma (HCC), is still unclear. In this study, we found that the expression of SREBP-1 in HCC tissues was significantly higher than those in matched tumor-adjacent tissues (p < 0.05). SREBP-1 was expressed at significantly higher levels in patients with large tumor size, high histological grade and advanced tumor-node-metastasis (TNM) stage (p < 0.05). The positive expression of SREBP-1 correlated with a worse 3-year overall and disease-free survival of HCC patients (p < 0.05). Additionally, SREBP-1 was an independent factor for predicting both 3-year overall and disease-free survival of HCC patients (p < 0.05). In vitro studies revealed that downregulation of SREBP-1 inhibited cell proliferation and induced apoptosis in both HepG2 and MHCC97L cells (p < 0.05). Furthermore, wound healing and transwell assays showed that SREBP-1 knockdown prominently inhibited cell migration and invasion in both HepG2 and MHCC97L cells (p < 0.05). These results suggest that SREBP-1 may serve as a prognostic marker in HCC and may promote tumor progression by promoting cell growth and metastasis.

Histone acetyltransferase PCAF Up-regulated cell apoptosis in hepatocellular carcinoma via acetylating histone H4 and inactivating AKT signaling

BackgroundPCAF is an important intrinsic histone acetyltransferases. This study tried to establish the effect of PCAF on HCC cell apoptosis.MethodBoth in vitro and in vivo experiments including IHC, DAPI staining, caspase 3/7 activity assay, BrdU assay, MTT assay, western immunoblotting and co-immunoprecipitation were used here.ResultsPCAF was found to be expressed at the low level in most of HCC cell lines. PCAF overexpression induced cell apoptosis and growth arrest with increased Histone H4 acetylation and inactivation of AKT signaling in Huh7 and HepG2 cells. The opposite results were obtained by silencing PCAF in Hep3B cells. The co-immunoprecipitation assay confirmed that PCAF protein was bound with histone H4 protein in the nucleus of Hep3B cells. Finally, the in vivo experiment confirmed the findings mentioned-above.ConclusionThese data identified PCAF promotes cell apoptosis and functions as a HCC repressor through acetylating histone H4 and inactivating AKT signaling.

MACC1 Suppresses Cell Apoptosis in Hepatocellular Carcinoma by Targeting the HGF/c-MET/AKT Pathway

Background & Aims: To investigate the expression and prognostic value of MACC1 in patients with HCC and identify the mechanism by which MACC1 inhibits HCC cell apoptosis. Methods: MACC1 and p-AKT expression was studied using immunohistochemistry of both HCC tissues and adjacent liver tissues. qRT-PCR and western immunoblotting were used to examine the expression of target genes at the mRNA and protein levels, respectively. The MTT assay was used to assess cell viability, and cell apoptosis was determined by DAPI staining, Annexin V/PI staining and Caspase 3/7 assay. Nude mice were used to perform in vivo experiments. Results: The overexpression of MACC1 was found in HCC tissues and was correlated with poor postsurgical prognosis. There was a positive relationship between MACC1 and p-AKT expression in HCC tissues. In vitro experiments showed that MACC1 repressed HCC cell apoptosis and promoted cell growth. Knockdown of c-MET abolished the anti-apoptotic function of MACC1. Next, MACC1 was verified to activate PI3K/AKT signaling by sensitizing HGF/c-MET signaling in HCC. MACC1 overexpression enhanced the HGF-driven phosphorylation of BAD, Caspase 9 and FKHRL1 and inhibited their pro-apoptotic functions in HCC cells. Finally, MACC1 was shown to inhibit cell apoptosis and promote HCC growth in vivo. Conclusions: This investigation revealed that MACC1 overexpression predicted worse prognosis after liver resection, which was attributed to the repression of HCC cell apoptosis via a molecular mechanism in which MACC1 accelerated the activation of the HGF/c-MET/PI3K/AKT pathway and phosphorylated BAD, Caspase 9 and FKHRL1, ultimately preventing their nuclear translocation and their pro-apoptotic function.

MACC1 expression correlates with PFKFB2 and survival in hepatocellular carcinoma.

OBJECTIVE To validate the relationship between MACC1 and 6-phosphofructo-2-kinase/fructose 2, 6 bisphosphatase (PFKFB2) expression as well as its clinicopathological features and prognostic significance in hepatocellular carcinoma. METHODS By using immunohistochemistry, we investigated the MACC1 and PFKFB2 protein expression in 60 pairs of hepatocellular carcinoma and corresponding non-tumor tissues. Using the Mann-Whitney U test, the Chi-square test, Kaplan-Meier survival analysis, Cox proportional hazard regression analysis and Spearman analysis, we studied the relationship between MACC1 and PFKFB2 protein expression and postoperative overall survival (OS) of the HCC patients. RESULTS MACC1 and PFKFB2 positive staining rates were significantly higher in hepatocellular carcinoma than in the corresponding nontumor tissues (P=0.012 and 0.04, respectively). The clinicopathological features evaluation revealed that positive expression of MACC1 was associated with a high Edmondson classification (P=0.007) and advanced TNM stage (P=0.027). Similar findings were evident for PFKFB2 expression (P=0.002 and P=0.027). MACC1 and PFKFB2 positive expression was associated with a lower OS rate (P=0.004 and 0.03, respectively). Kaplan-Meier survival and Cox proportional hazard regression analyses revealed MACC1 positive expression to be a prognostic factor for postoperative OS, but PFKFB was not. CONCLUSION Highly expressed MACC1 and PFKFB2 protein were associated with TNM stage, Edmondson -Steier classification and overall survival. MACC1 may affect tumor metabolism partly through expression and phophorylation of PFKFB2.

Laparoscopic Splenectomy and Esophagogastric Devascularization Is a Safe, Effective, Minimally Invasive Alternative for the Treatment of Portal Hypertension With Refractory Variceal Bleeding

Open splenectomy and esophagogastric devascularization (OSED) is a typical surgery for portal hypertension. Because of the high morbidity associated with it, it is desirable to develop a minimally invasive alternative. To investigate the safety and effect of laparoscopic splenectomy and esophagogastric devascularization (LSED), we performed LSED for 24 patients suffering from portal hypertension with refractory variceal bleeding while conducting OSED for 30 patients. The perioperative data and follow-up results were analyzed. Operation times were similar in both groups. Less intraoperative blood and faster return of gastrointestinal function were found in the LSED group. The LSED group had lower levels of alanine aminotransferase, aspartate aminotransferase, and total bilirubin after surgery. In both groups, the levels of platelet count, white blood cell count, or hemoglobin were increased after operation dramatically. During the follow-up period (range = 3-36 months), no patient had recurrent hypersplenism or variceal bleeding. Hence, LSED is a safe and minimally invasive intervention for portal hypertension with refractory variceal bleeding.