The RNF214-TEAD-YAP signaling axis promotes hepatocellular carcinoma progression via TEAD ubiquitylation.

RNF214 is an understudied ubiquitin ligase with little knowledge of its biological functions or protein substrates. Here we show that the TEAD transcription factors in the Hippo pathway are substrates of RNF214. RNF214 induces non-proteolytic ubiquitylation at a conserved lysine residue of TEADs, enhances interactions between TEADs and YAP, and promotes transactivation of the downstream genes of the Hippo signaling. Moreover, YAP and TAZ could bind polyubiquitin chains, implying the underlying mechanisms by which RNF214 regulates the Hippo pathway. Furthermore, RNF214 is overexpressed in hepatocellular carcinoma (HCC) and inversely correlates with differentiation status and patient survival. Consistently, RNF214 promotes tumor cell proliferation, migration, and invasion, and HCC tumorigenesis in mice. Collectively, our data reveal RNF214 as a critical component in the Hippo pathway by forming a signaling axis of RNF214-TEAD-YAP and suggest that RNF214 is an oncogene of HCC and could be a potential drug target of HCC therapy.

Nontraditional translation is the key to UFMylation and beyond.

The Ubiquitin-fold modifier 1 (Ufm1) is a ubiquitin-like protein that can also be conjugated to protein substrates and subsequently alter their fates. Both UFMylation and de-UFMylation are mediated by Ufm1-specific proteases (UFSPs). In humans, it is widely believed that UFSP2 is the only active Ufm1 protease involved in Ufm1 maturation and de-UFMylation, whereas UFSP1 is thought to be inactive. Here, Liang et al. provide strong evidence showing that human UFSP1 is also an active Ufm1 protease. These results solve an age-old mystery in the human Ufm1 conjugation system and could have a greater impact not only on Ufm1 biology but also on the translation of genes employing nontraditional start codons.

Experimental and theoretical investigation of the enhancement of the photo-oxidation of Hg0 by CeO2-modified morphology-controlled anatase TiO2.

This study aims to investigate the coeffects of predominantly exposed anatase TiO2{001} and {101} and CeO2 loading on the photo-oxidation of Hg0 to relieve the adverse effects caused by higher temperatures of 50-250 °C. The effect of loading CeO2 on the photocatalytic activity of morphology-controlled TiO2 was not only investigated using DFT with U correction but also experimentally analyzed by characterizing the electrochemical properties and the formation of free radicals. The theoretical calculation showed that CeO2 loading on TiO2{101} was more stable than that on TiO2{001}. Accordingly, a larger portion of CeO2 was observed to anchor to the (101) plane than to the (001) plane. CeO2 loading is more beneficial for increasing the distribution of photo-induced electrons and holes on the surface of 7%CeTi than on the surface of TiO2 and increases the energy difference between the conduction band edge of 7%CeTi and the standard redox potential of O2/·O2-. Correspondingly, the photocatalytic removal efficiencies (PREs) of Hg0 by 7%CeTi were significantly enhanced compared with those of pristine TiO2. The effect of CeO2 was highly morphologically dependent on the photocatalytic activity. This study provides valuable insight into surface engineering strategies for morphology-controlled photocatalysts for air pollution control technology.

Identification of osalmid metabolic profile and active metabolites with anti-tumor activity in human hepatocellular carcinoma cells.

BACKGROUNDS: Ribonucleotide reductase (RR) catalyzes the essential step in the formation of all four deoxynucleotides. Upregulated activity of RR plays an active role in tumor progression. As the regulatory subunit of RR, ribonucleotide reductase subunit M2 (RRM2) is regarded as one of the effective therapeutic targets for DNA replication-dependent diseases, such as cancers. Recent studies have revealed that osalmid significantly inhibits the activity of RRM2, but the metabolic profile of osalmid remains unknown. OBJECTIVE: The aim of this study was to clarify the metabolic profile including metabolites, isoenzymes and metabolic pathways of osalmid. The anti-human hepatocellular carcinoma activity and mechanism of metabolites were further investigated. MATERIALS AND METHODS: Ultra high-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC/Q-TOF-MS) was used for identifying metabolites and for characterizing phase I and phase II metabolic pathways with recombinant enzymes or in human liver microsomes of osalmid. The eHiTS docking system was used for potential RRM2 inhibitor screening among metabolites. Cytotoxicity assays were performed for evaluating cell proliferation inhibitory activity of metabolites. Cell cycle assays and cell apoptosis assays were assessed by flow cytometry. Western blotting analysis of RRM2, cyclin D1, p21, p53, phosphorylated p53, Bcl-2 and Bax was performed to explore the anti-hepatocellular carcinoma mechanism of the active metabolites. RESULTS: Ten metabolites of osalmid were identified, and none of them have been reported previously. Hydroxylation, glucuronidation, sulfonation, acetylation and degradation were recognized as the main metabolic processes of osalmid. Isozymes of CYP1A2, CYP2C9, UGT1A1, UGT1A6, UGT1A9, UGT2B7 and UGT2B15 were involved in phase I and phase II metabolism of osalmid. Metabolites M7, M8 and M10 showed higher binding affinities with the RRM2 active site than osalmid. Metabolite M7 exhibited potent inhibitory activity to hepatocellular carcinoma cell lines by both competitive inhibition and down-regulation of RRM2. Moreover, M7 significantly induced cell cycle arrest and apoptosis by activating p53-related pathways. CONCLUSIONS: The metabolic profile of osalmid was identified. M7 significantly inhibited human hepatocellular carcinoma progression by inhibiting RRM2 activity. Furthermore, M7 induced cell cycle arrest and apoptosis by activating p53-related signaling pathways.

A novel multitarget kinase inhibitor BZG with potent anticancer activity in vitro and vivo enhances efficacy of sorafenib through PI3K pathways in hepatocellular carcinoma cells.

OBJECTIVES: BZG as a novel multitarget kinase inhibitor, has been proved to inhibit the proliferation of hepatocellular carcinoma (HCC) previously. In this study, we aimed at investigating the underlying mechanisms of BZG with and without sorafenib and evaluating their anti-tumor effects as well as whether BZG could inhibit the activation of phosphoinositide 3-kinase (PI3K)/AKT signaling which is associated with acquired resistance to sorafenib. METHODS: We evaluated the proliferation of HCC cells by CCK-8 assay and colony formation assay. Cell apoptosis was assessed by Hoechst 33342 staining assay and flow cytometry. Western blot was used to detect the critical enzymes in the PI3K pathways and the expression of p-ERK after BZG alone and combined with sorafenib treatments. Huh-7 hepatocellular carcinoma xenograft model was used to evaluate the anti-carcinoma effects of BZG alone and in combination in vivo. HE staining and TUNEL assay tested the necrosis of tumor tissue and apoptosis of tumor cells. RESULTS: BZG could inhibit the proliferation of HCC cells in a dose-dependent manner. The combination of BZG and sorafenib produced synergistic effects. PI3K and p-ERK pathway were involved in the anti-tumor functions of BZG alone and when combined with sorafenib. In addition, the combination treatment was seen to be more effective in inhibiting the expression of p-AKT, p-ERK and p-mTOR. Furthermore, Tumor necrosis and cell apoptosis were also observed in Huh-7 hepatocellular carcinoma xenograft models. CONCLUSIONS: BZG is an attractive agent for treating HCC. The effects of BZG and sorafenib's co-treatment on HCC are more effective than BZG or sorafenib alone.