Pei-Yuan Li

MicroRNA-143 suppresses gastric cancer cell growth and induces apoptosis by targeting COX-2.

AIMnTo investigate the function of microRNA-143 (miR-143) in gastric cancer and explore the target genes of miR-143.nnnMETHODSnA quantitative real-time reverse transcription-polymerase chain reaction (RT-PCR) analysis was performed to evaluate miR-143 expression in gastric cancer cell lines. After transfecting gastric cancer cells with miR-143-5p and miR-143-3p precursors, Alamar blue and apoptosis assays were used to measure the respective proliferation and apoptosis rates. Cyclooxygenase-2 (COX-2) expression was determined by real-time RT-PCR and Western blot assays after miR-143 transfection. Reporter plasmids were constructed, and a luciferase reporter assay was used to identify the miR-143 binding site on COX-2.nnnRESULTSnBoth miR-143-5p and miR-143-3p were significantly downregulated in multiple gastric cancer cell lines. Forced miR-143-5p and miR-143-3p expression in gastric cancer cells produced a profound cytotoxic effect. MiR-145-5p transfection into gastric cancer cells resulted in a greater growth inhibitory effect (61.23% ± 3.16% vs. 46.58% ± 4.28%, P < 0.05 in the MKN-1 cell line) and a higher apoptosis rate (28.74% ± 1.93% vs. 22.13% ± 3.31%, P < 0.05 in the MKN-1 cell line) than miR-143-3p transfection. Further analysis indicated that COX-2 expression was potently suppressed by miR-143-5p but not by miR-143-3p. The activity of a luciferase reporter construct that contained the 3-untranslated region (UTR) of COX-2 was downregulated by miR-143-5p (43.6% ± 4.86%, P < 0.01) but not by miR-143-3p. A mutation in the miR-145-5p binding site completely ablated the regulatory effect on luciferase activity, which suggests that there is a direct miR-145-5p binding site in the 3-UTR of COX-2.nnnCONCLUSIONnBoth miR-143-5p and miR-143-3p function as anti-oncomirs in gastric cancer. However, miR-143-5p alone directly targets COX-2, and it exhibits a stronger tumor suppressive effect than miR-143-3p.

MiR-497 suppresses angiogenesis and metastasis of hepatocellular carcinoma by inhibiting VEGFA and AEG-1

Hepatocellular carcinoma (HCC) is a worldwide malignance and displays marked vascular abnormalities and active metastasis. MicroRNAs (miRNAs) have been shown to play important roles in regulating tumor properties in cancer, however, whether miR-497 contributes to HCC angiogenesis or metastasis remains unclear. In this study, we found that miR-497 was significantly down-regulated in HCC tissue samples and cell lines. Gain-of-function and loss-of-function studies revealed that miR-497 could repress both the pro-angiogenic and metastatic ability of HCC cells. Subsequent investigations disclosed that miR-497 directly inhibited the 3′-untranslated regions (UTRs) of vascular endothelial growth factor A (VEGFA) and astrocyte elevated gene-1 (AEG-1). Furthermore, overexpression of these targets antagonized the function of miR-497. Based on nude mouse models, we demonstrated that overexpression of miR-497 significantly repressed microvessel densities in xenograft tumors and reduced pulmonary metastasis. In conclusion, our findings indicate that miR-497 downregulation contributes to angiogenesis and metastasis in HCC.

The role of autophagy in hepatocellular carcinoma: friend or foe

Autophagy is an evolutionarily conserved lysosome-dependent catabolic process which degrades cell’s components in order to recycle substrates to exert optimally and adapt to tough circumstances. It is a critical cellular homeostatic mechanism with stress resistance, immunity, antiaging, and pro-tumor or anti-tumor effects. Among these, the role of autophagy in cancer is the most eye-catching that is not immutable but dynamic and highly complex. Basal autophagy acts as a tumor suppressor by maintaining genomic stability in normal cells. However, once a tumor is established, unbalanced autophagy will contribute to carcinoma cell survival under tumor microenvironment and in turn promote tumor growth and development. The dynamic role of autophagy can also apply on hepatocellular carcinoma (HCC). HCC is a highly malignant cancer with high morbidity and poor survival rate. Decline or overexpression of autophagic essential genes such as ATG7, ATG5 or Beclin 1 plays a key role in the occurrence and development of HCC but the exact mechanisms are still highly controversial. Signaling pathways or molecules involving in autophagy, for example PI3K/AKT/mTOR pathway, ERK/MAPK pathway, PERK pathway, p53, LncRNA PTENP1 (Long non-coding RNA PTENP1), microRNA-375 and so on, occupy an important position in the complex role of autophagy in HCC. Here, we discuss the dynamic role, the signaling pathways and the potential prognostic and therapy value of autophagy in HCC.Autophagy is an evolutionarily conserved lysosome-dependent catabolic process which degrades cells components in order to recycle substrates to exert optimally and adapt to tough circumstances. It is a critical cellular homeostatic mechanism with stress resistance, immunity, antiaging, and pro-tumor or anti-tumor effects. Among these, the role of autophagy in cancer is the most eye-catching that is not immutable but dynamic and highly complex. Basal autophagy acts as a tumor suppressor by maintaining genomic stability in normal cells. However, once a tumor is established, unbalanced autophagy will contribute to carcinoma cell survival under tumor microenvironment and in turn promote tumor growth and development. The dynamic role of autophagy can also apply on hepatocellular carcinoma (HCC). HCC is a highly malignant cancer with high morbidity and poor survival rate. Decline or overexpression of autophagic essential genes such as ATG7, ATG5 or Beclin 1 plays a key role in the occurrence and development of HCC but the exact mechanisms are still highly controversial. Signaling pathways or molecules involving in autophagy, for example PI3K/AKT/mTOR pathway, ERK/MAPK pathway, PERK pathway, p53, LncRNA PTENP1 (Long non-coding RNA PTENP1), microRNA-375 and so on, occupy an important position in the complex role of autophagy in HCC. Here, we discuss the dynamic role, the signaling pathways and the potential prognostic and therapy value of autophagy in HCC.

Netrin-1 Induces Epithelial–Mesenchymal Transition and Promotes Hepatocellular Carcinoma Invasiveness

AbstractBackgroundHypoxia is often found in solid tumors and is associated with tumor progression and poor clinical outcomes. We elucidated the mechanism by which netrin-1 released under hypoxic stress can induce epithelial–mesenchymal transition (EMT) to promote invasion in hepatocellular carcinoma (HCC) cells.nMethodsThe expression of netrin-1 and the dependent receptors UNC5H and deleted in colorectal cancer (DCC) in HCC was examined by immunohistochemistry or western blot. The HepG2 cells were cultured in 21xa0% O2 (normoxia) or 1xa0% O2 (hypoxia) for 24xa0h. The release of netrin-1 from hypoxic cells was detected by ELISA. Expression of E-cadherin and vimentin were examined by western blot. Inverted microscopy or confocal microscopy was used to show the cell morphology or cytoskeletal rearrangements. Cell invasion induced by hypoxia was analyzed by Transwell chamber. Cytokine IL-8 and IL-10 mRNA levels were assessed by real-time PCR.ResultsThe expression of netrin-1 was increased in HCC tissue and cell lines. The dependent receptors UNC5H and DCC were decreased in most HCC cell lines. Hypoxia induced netrin-1 release in a time-dependent manner. EMT induction was found to occur in hypoxic HCC cells in a process that was dependent on the extracellular release of netrin-1. Moreover, overexpression of netrin-1 resulted in EMT induction in normoxic tumor cells. Cytoskeletal rearrangements were found to occur and cell invasion was increased in cells with netrin-1 overexpression. Lastly, mRNA of IL-8 and IL-10 were also increased after recombinant human netrin-1 treatment.ConclusionThese results suggest that in hypoxic HCC cells, netrin-1 activates downstream signaling pathways to induce EMT activation with subsequent production of multiple inflammatory mediators which in turn promotes cancer invasion.

Traditional Chinese herbal extracts inducing autophagy as a novel approach in therapy of nonalcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is one of the leading causes of chronic liver diseases around the world due to the modern sedentary and food-abundant lifestyle, which is characterized by excessive fat accumulation in the liver related with causes other than alcohol abuse. It is widely acknowledged that insulin resistance, dysfunctional lipid metabolism, endoplasmic reticulum stress, oxidative stress, inflammation, and apoptosis/necrosis may all contribute to NAFLD. Autophagy is a protective self-digestion of intracellular organelles, including lipid droplets (lipophagy), in response to stress to maintain homeostasis. Lipophagy is another pathway for lipid degradation besides lipolysis. It is reported that impaired autophagy also contributes to NAFLD. Some studies have suggested that the histological characteristics of NAFLD (steatosis, lobular inflammation, and peri-sinusoid fibrosis) might be improved by treatment with traditional Chinese herbal extracts, while autophagy may be induced. This review will provide insights into the characteristics of autophagy in NAFLD and the related role/mechanisms of autophagy induced by traditional Chinese herbal extracts such as resveratrol, Lycium barbarum polysaccharides, dioscin, bergamot polyphenol fraction, capsaicin, and garlic-derived S-allylmercaptocysteine, which may inhibit the progression of NAFLD. Regulation of autophagy/lipophagy with traditional Chinese herbal extracts may be a novel approach for treating NAFLD, and the molecular mechanisms should be elucidated further in the near future.

Celecoxib alleviates nonalcoholic fatty liver disease by restoring autophagic flux

Nonalcoholic fatty liver disease (NAFLD) is a kind of liver lipid synthesis and degradation imbalance related with metabolic syndrome. Celecoxib shows the function of ameliorating NAFLD, but the underlying mechanisms remain unknown. Here, we discuss the possible mechanisms of celecoxib alleviating NAFLD by restoring autophagic flux. Lipids were accumulated in L02 cells treated with palmitate as well as SD rats fed with high-fat diet. Western blot showed that LC3 II/I was higher and p62 was lower on the early stage of steatosis while on the late stage both of them were higher, indicating that autophagic flux was activated on the early stage of steatosis, but blocked on the late stage. Rapamycin alleviated steatosis with activating autophagic flux while chloroquine aggravated steatosis with inhibiting autophagic flux. COX-2 siRNA and celecoxib were used to inhibit COX-2. Western blot and RFP-GFP-LC3 double fluorescence system indicated that celecoxib could ameliorate steatosis and restore autophagic flux in L02 cells treated with palmitate as well as SD rats fed with high-fat diet. In conclusion, celecoxib partially restores autophagic flux via downregulation of COX-2 and alleviates steatosis in vitro and in vivo.

Familial High-Serum Gamma-Glutamyltransferase Activity

1 Center for Exocrine Disorders, Department of Molecular and Cell Biology, Boston University Henry M. Goldman School of Dental Medicine , Boston , Massachusetts , USA ; 2 First Department of Medicine, University of Szeged , Szeged , Hungary ; 3 First Department of Surgery, Semmelweis University , Budapest , Hungary ; 4 Institute for Translational Medicine and First Department of Medicine, University of Pécs , Pécs , Hungary ; 5 MTA-SZTE Translational Gastroenterology Research Group , Szeged , Hungary ; 6 The last two authors contributed equally to this work . Correspondence: Péter Hegyi, MD, PhD, DSci, Institute for Translational Medicine and First Department of Medicine, University of Pécs , Szigeti út 12 , Pécs H-7624 , Hungary or Miklós Sahin-Tóth, Center for Exocrine Disorders, Department of Molecular and Cell Biology, Boston University Henry M. Goldman School of Dental Medicine , 72 East Concord Street, Evans-433 , Boston , Massachusetts 02118 , USA . E-mail: p.hegyi@tm-pte.org or miklos@bu.edu