Project description:Abstract Rationale: Interferon (IFN) plays a key role in immunotherapy by acting through interferon-stimulated genes. Interferon resistance limits its efficacy. Ubiquitination modification of key proteins is a popular research direction in hepatocellular carcinoma (HCC), and it is also one of the important mechanisms of interferon resistance. This study is dedicated to discovering the link between the pathogenesis of interferon resistance and ubiquitination modifications in HCC. Methods: We first combined the TCGA LIHC dataset and genes from the iUUCD 2.0 database to screen the most promising ubiquitination-related gene, UBE2O, in HCC using a bioinformatics approach. A combination of proteomic analysis, mass spectrometry, and survival analysis was used to screen for pathways and proteins negatively regulated by UBE2O. The effect of silencing UBE2O on interferon sensitivity in HCC cells was assessed using in vitro clone formation, migration, and wound healing assays and in vivo subcutaneous tumor xenograft models. Changes in the half-life of substrates following inhibition of UBE2O were assessed using a cycloheximide method. Two databases were used to predict ubiquitination sites on IFIT3. After rescue experiments to exclude the effect of substrate, proteomic analysis was reperformed to analyze the effect on the interferon pathway and phenotype. The effect on substrate and interferon sensitivity was observed using arsenic trioxide (ATO) to inhibit UBE2O. Results: Initially, UBE2O was deduced from 807 UUCRGs in the TCGA LIHC dataset by six consecutive screening steps. UBE2O was significantly overexpressed in HCC cell lines and tissues compared to the corresponding normal group, and low expression of UBE2O was associated with a better prognosis. UBE2O was knocked down for proteomic analysis, and the results suggested that UBE2O negatively regulates the interferon-alpha/beta signaling (p＜0.01) and the interferon pathway (p＜0.01). IFIT3 in the interferon pathway was identified as a possible ubiquitinated substrate of UBE2O by combining mass spectrometry, the human protein atlas (HPA), and TCGA-based survival analysis. There was a significant negative correlation between UBE2O and IFIT3, including survival analysis showing opposite trends and a negative correlation in protein expression. UBE2O binds to IFIT3, and interferon-α promotes this binding. The stability of IFIT3 protein increased with decreasing UBE2O (p＜0.05), and these effects disappeared with the mutational inactivation of UBE2O. K236 of IFIT3 is the active site of ubiquitination. By increasing IFIT3, the knockdown of UBE2O increases the sensitivity of HCC cells to interferon, leading to reduced proliferation and migration (all p＜0.05). These effects disappeared after the elimination of IFIT3. Additionally, ATO inhibited UBE2O and therefore increased interferon sensitivity in HCC cells. Conclusions: UBE2O exerts a protumor role and targets a new substrate, IFIT3, for ubiquitination and degradation, impeding the interferon pathway activation and interferon sensitization in HCC. The findings will shed light on the interferon-based targeted or combination therapeutic strategies for HCC in the future.

Project description:1,7-bis(4-hydroxy-3-methoxyphenyl)heptane-3,5-dione (tetrahydrocurcumin, THC) is a major bioactive metabolite of curcumin (the principal active ingredient of Curcuma longa L.), and overcomes the low bioavailability of curcumin, demonstrating the potential anti-inflammatory, antioxidant and neuroprotective properties, etc, some of which were considered to be even superior to curcumin. In the present study, the protective properties of THC in the hippocampus of APP/PS1 mice, and the effects of THC against Aβ-induced toxicity in BV-2 cells were explored. The data in vitro showed that Aβ induced decreased cell viability, and cell cycle arrest and apoptosis in BV-2 cells, which could be ameliorated by THC. In vivo, THC administration was able to rescue learning and memory, and reduce Aβ burden in the hippocampus of APP/PS1 mice. By comprehensive proteomic analysis of the hippocampus of mice, a total of 157 differentially expressed proteins were identified in APP/PS1 mice treated with THC (comparing with APP/PS1 mice), which were enriched in “T cell activation”, “lymphocyte proliferation” and “protein oligomerization”, etc. The results of Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis suggested that the effects of THC on the cell cycle and apoptosis were mostly related to the “Ras signaling pathway” and “JAK−STAT signaling pathway”, etc. Using Western blot and ELISA, the down-regulation of Gab2 and K-Ras, and the up-regulation of caspase-3, TGF-β1 and TNF-ɑ were found in APP/PS1 mice. THC attenuated the abnormal expression of Gab2, K-Ras, caspase-3 and TNF-ɑ, and up-regulated Bag1 and TGF-β1 expression in APP/PS1 mice. In BV-2 cells, Aβ induced the down-regulation of Gab2, K-Ras and TGF-β1, and the overexpression of caspase-3, PARP1, cleaved-PARP1 and TNF-ɑ, which were markedly restored by THC. Moreover, THC up-regulated Bag1 expression in BV-2 cells treated with Aβ. The decreased transcriptional expression levels of Ccnd2 and Cdkn1a was also observed in Aβ-treated BV-2 cells. THC treatment alleviated down-regulation of Ccnd2, but did not affect the abnormal transcriptional expression of Cdkn1a caused by Aβ in BV-2 cells. For the first time, we identified that the action of THC in preventing AD was associated with inhibition of cell cycle arrest and apoptosis of microglia via the Ras/ERK signaling pathway, shedding new light on the role of THC in alleviating the progression of AD.

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Adenosine-rich extract of Ganoderma lucidum: a safe and effective lipid-lowering substance via regulating expression and modulation of PPAR signaling pathway

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Adenosine-rich extract of Ganoderma lucidum: A safe and effective lipid-lowering substance.

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