Dataset Information

UBE2O targets a novel substrate IFIT3 for ubiquitination and degradation, impeding the interferon pathway activation and interferon sensitization in hepatocellular carcinoma

ABSTRACT: 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.

INSTRUMENT(S): Orbitrap Fusion Lumos, Orbitrap Exploris 480

ORGANISM(S): Homo Sapiens (human)

TISSUE(S): Cell Culture

SUBMITTER: li heng

LAB HEAD: Wang Jiabei

PROVIDER: PXD039711 | Pride | 2024-01-26

REPOSITORIES: Pride

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Publications

UBE2O reduces the effectiveness of interferon-α via degradation of IFIT3 in hepatocellular carcinoma.

Li Heng H Liu Yao Y Cheng Can C Wu Yang Y Liang Shu-Hang SH Wu Liang L Wang Hong H Tu Cong-Yin CY Yao Han-Hui HH Meng Fan-Zheng FZ Zhang Bo B Wang Wei W Wang Jia-Bei JB Liu Lian-Xin LX

Cell death & disease 20231221 12

Interferon (IFN) exerts its effects through interferon-stimulated genes (ISGs), but its efficacy is limited by interferon resistance, which can be caused by the ubiquitination of key proteins. UBE2O was initially identified as a promising therapeutic target based on data from the TCGA and iUUCD 2.0 databases. Through the inhibition of UBE2O, interferon α/β signaling and overall interferon signaling were activated. Integrating data from proteomic, mass spectrometry, and survival analyses led to t ...[more]

PMID: 38129382

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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:BACKGROUND & AIMS: Hepatocellular carcinoma (HCC) has a high mortality rate due to the lack of effective treatments and drugs. Arsenic trioxide (As2O3, ATO, arsenious acid), which has been proved to successfully treat acute promyelocytic leukemia (APL), was recently reported to show therapeutic potential in solid tumors including liver cancer. Although the mechanistic effects of ATO in APL are established, its anticancer mechanism of action in HCC is still unclear. METHODS: We established an HCC subcutaneous xenograft and intrahepatic metastasis mouse model. In CSC models, tumorspheres and the flow cytometry analysis of CSC markers together with limiting dilution and serial transplantation were used. We compared mRNA expression profiles of the ATO-treated and control cells with mRNA microarray. The expression of target molecule or a clinical correlation was analyzed by immunohistochemistry staining in tissues from ATO-treated mouse and 76 HCC patients. We generated five stable minichromosome maintenance protein 7 (MCM7)-knockdown and two stable MCM7-overexpression HCC cell lines. The chromatin immunoprecipitation (ChIP) assays, immunoprecipitation (IP) assays, the dual luciferase reporter assays, a green biarsenical labeling reagent (FlAsH-EDT2) and a “competing endogenous RNA” (ceRNA) analysis were used. RESULTS: ATO could inhibit the liver tumor-initiating capacity and distant metastasis and prolongs survival in mice. We then screened and found that ATO downregulates the overexpression of MCM7 which is correlated with the progression and prognosis in HCC patients. Knockdown of MCM7 expression recapitulates the inhibition function of ATO on self-renewal of cancer stem cells (CSCs), while overexpression of MCM7 abolishes the inhibition function of ATO on tumorsphere formation. Most importantly, we revealed that ATO directly binds to the MCM7 protein and disturbs the interaction between serum response factor (SRF) and MCM7, resulting in downregulation of MCM7 transcription. A ceRNA analysis also indicated the alterations of endogenous MCM7-associated gene networks involved in stemness-related signaling pathways and cell differentiation. CONCLUSIONS: Here, for the first time, we report that ATO inhibits liver CSCs through blocking the interaction between SRF/MCM7 and suppressing MCM7 autoregulation activity.

Dataset Information

UBE2O targets a novel substrate IFIT3 for ubiquitination and degradation, impeding the interferon pathway activation and interferon sensitization in hepatocellular carcinoma

Publications

UBE2O reduces the effectiveness of interferon-α via degradation of IFIT3 in hepatocellular carcinoma.

Similar Datasets

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