RNA sequencing (RNA-SEQ) of USP39 knockdown by shRNA in ovarian cancer cells
Ontology highlight
ABSTRACT: High-grade serous ovarian carcinoma is the most lethal type of gynecologic malignancy.Emerging evidences have suggested the vital roles of splicing factor in the human cancers. RNA splicing pathways was found excessive activated in HGSOC. USP39 was one of overexpressed splicing factor in HGSOC. However, the biological function and concrete regulatory mechanism of USP39 in ovarian cancer remain unclear. In this study, we investigate the oncogenic roles of the splicing factor USP39 in HGSOC through facilitated the growth speed and invasion of ovarian cancer cells.Elevated USP39 expression levels, based on immunohistochemistry staining, were associated with poor survival in HGSOC patients. In order to investigate the regulatory mechanism of USP39 in ovarian cancer,we performed RNA-seq in A2780 cells with USP39 knock down compared with control in three repeat. HMGA2 was identified as USP39 target gene because of different expression and downregulated splicing efficiency.
Project description:High-grade serous ovarian carcinoma is the most lethal type of gynecologic malignancy.Emerging evidences have suggested the vital roles of splicing factor in the human cancers. RNA splicing pathways was found excessive activated in HGSOC. USP39 was one of overexpressed splicing factor in HGSOC. However, the biological function and concrete regulatory mechanism of USP39 in ovarian cancer remain unclear. In this study, we investigate the oncogenic roles of the splicing factor USP39 in HGSOC through facilitated the growth speed and invasion of ovarian cancer cells.Elevated USP39 expression levels, based on immunohistochemistry staining, were associated with poor survival in HGSOC patients. In order to investigate the binding peaks of USP39 in ovarian cancer,we performed RIP-seq in A2780 cells with Flag-USP39 overexpression.
Project description:High-grade serous ovarian carcinoma is the most lethal type of gynecologic malignancy.Emerging evidences have suggested the vital roles of splicing factor in the human cancers. RNA splicing pathways was found excessive activated in HGSOC. USP39 was one of overexpressed splicing factor in HGSOC. However, the biological function and concrete regulatory mechanism of USP39 in ovarian cancer remain unclear. In this study, we investigate the oncogenic roles of the splicing factor USP39 in HGSOC through facilitated the growth speed and invasion of ovarian cancer cells.Elevated USP39 expression levels, based on immunohistochemistry staining, were associated with poor survival in HGSOC patients. Since many RNA-binding proteins showed DNA-binding ability , we performed ChIP-seq in A2780 cells with Flag-USP39 overexpression in order to detect the bindng of USP39 to DNA and POLR2A was used as a positive control.
Project description:KRAS is the most frequently mutated oncogene in human cancer, but its therapeutic targeting remains challenging. Here, we report a synthetic lethal screen with a library of deubiquitinases and identify USP39, which encodes an essential splicing factor, as a critical gene for the viability of KRAS-dependent cells. We show that the essentiality of USP39 for these cells is based on its critical role in splicing regulation, as splicing fidelity inhibitors also decrease preferentially the proliferation rate of KRAS-active cells. Moreover, depletion of DHX38, an USP39-interacting splicing factor, also reduces the viability of these cells. Furthermore, we show that USP39 is upregulated in lung and colon carcinomas and its expression correlates with KRAS levels and poor clinical outcome, supporting the oncogenic role of this deubiquitinase. Accordingly, our work provides critical information for the development of splicing-directed antitumor treatments and supports the potential of USP39-targeting strategies for the development of anticancer therapies.
Project description:Regulation of alternative splicing (AS) is crucial for gene expression and enables a single transcript to yield multiple isoforms that increase transcriptome and proteome diversity. Dysregulated AS has been linked to the development of non-alcoholic fatty liver diseases (NAFLD). However, the splicing factors involved in hepatic homeostasis and their functional mechanisms remain to be further characterized. Here, we report that spliceosome component Usp39 plays a critical role in the regulation of hepatocyte lipid homeostasis. We found that Usp39 expression is downregulated in hepatic tissues of NAFLD and non-alcoholic steatohepatitis (NASH) subjects. We observed increased lipid accumulation, spontaneous steatosis and impaired autophagy, lipophagy in particular, in mice with hepatocyte-specific Usp39 deletion. Combined analysis of RIP-seq and RNA-seq data revealed that Usp39 regulates AS of several autophagy-related genes including Hsf1. More specifically, deletion of Usp39 resulted in alternative 5’ splice site selection of exon 6 in Hsf1 and consequently reduced expression. Hsf1 was also found to be downregulated in NAFLD/NASH mice and patients. Importantly, overexpression of Hsf1 restored lipophagy, attenuated lipid accumulation and alleviated NASH caused by Usp39 deficiency. Taken together, our findings indicate that Usp39-mediated AS is crucial for sustaining lipophagy and lipid homeostasis in the liver.
Project description:Abnormal alternative splicing (AS) caused by alterations to splicing factors contributes to tumor progression. Nonetheless, the relevant targets and mechanisms remain elusive in hepatocellular carcinoma (HCC). Here, we reported that overexpression of Ubiquitin-specific protease 39 (USP39), a spliceosome component of the U4/U6.U5 tri-snRNP complex, is associated with poor clinical outcomes and proliferative signaling. Functionally, hepatocyte-specific USP39 knockin mice exhibited enhanced hepatocarcinogenesis. In vitro, USP39 promoted HCC cell proliferation and cell cycle progression in a spliceosome-dependent manner. Transcriptomic analysis revealed that USP39 depletion led to comprehensively impaired constitutive splicing and intriguingly, selective AS of hundreds of genes. USP39-mediated splicing switch of KANK2-S to KANK2-L increased the tumorigenic potential of HCC cells through accelerating KANK2 translation. Mechanistically, USP39 modulates exon inclusion/exclusion via interaction with SRSF6 or hnRNPC in a position-dependent manner. These findings highlight a role for USP39 as a splicing regulator in HCC biology and establishing its position-dependent splicing model.
Project description:Regulation of alternative splicing (AS) is crucial for gene expression and enables a single transcript to yield multiple isoforms that increase transcriptome and proteome diversity. Dysregulated AS has been linked to the development of non-alcoholic fatty liver diseases (NAFLD). However, the splicing factors involved in hepatic homeostasis and their functional mechanisms remain to be further characterized. Here, we report that spliceosome component Usp39 plays a critical role in the regulation of hepatocyte lipid homeostasis. We found that Usp39 expression is downregulated in hepatic tissues of NAFLD and non-alcoholic steatohepatitis (NASH) subjects. We observed increased lipid accumulation, spontaneous steatosis and impaired autophagy, lipophagy in particular, in mice with hepatocyte-specific Usp39 deletion. Combined analysis of RIP-seq and RNA-seq data revealed that Usp39 regulates AS of several autophagy-related genes including Hsf1. More specifically, deletion of Usp39 resulted in alternative 5’ splice site selection of exon 6 in Hsf1 and consequently reduced expression. Hsf1 was also found to be downregulated in NAFLD/NASH mice and patients. Importantly, overexpression of Hsf1 restored lipophagy, attenuated lipid accumulation and alleviated NASH caused by Usp39 deficiency. Taken together, our findings indicate that Usp39-mediated AS is crucial for sustaining lipophagy and lipid homeostasis in the liver.
Project description:Ovarian cancer is the most lethal gynecologic cancer. High-grade serous ovarian carcinoma (HGSOC) is the most common histologic subtype, accounting for three quarters of ovarian cancer. To clarify the changes of gene expression in serous ovarian cancer, we performed lncRNA and mRNA microarrays to identify differentially expressed lncRNAs and mRNAs in High-grade and Low-grade serous ovarian carcinoma compared with Normal fallopian tube.
Project description:Ovarian cancer is the most lethal gynecologic malignancy in women, and high-grade serous ovarian cancer (HGSOC) is the most common subtype. Currently, no clinical test has been approved by the FDA to screen the general population for ovarian cancer. This underscores the critical need for the development of a robust methodology combined with novel technology to detect diagnostic biomarkers for HGSOC in the sera of women. Targeted mass spectrometry (MS) can be used to identify and quantify specific peptides/proteins in complex biological samples with high accuracy, sensitivity, and reproducibility. In this study, we sought to develop and conduct analytical validation of a multiplexed Tier 2 targeted MS parallel reaction monitoring (PRM) assay for the relative quantification of 23 putative ovarian cancer protein biomarkers in sera.
Project description:We used HeLa cells and RPE1 cells after knockdown (KD) of USP39 using siRNAs. We compared differential expression and alternative splicing between Control and KD cells.
Project description:RNA splicing and protein degradation systems allow the functional adaptation of the proteome in response to changing cellular contexts. However, the regulatory mechanisms connecting these processes remain poorly understood. Here, we show that impaired spliceosome assembly caused by USP39 deficiency leads to a pathogenic splicing profile characterized by the use of cryptic 5′ splice sites. To explore the interactions of USP39 and the effect of its depletion in HeLa cells, we performed complexome profiling of nuclear lysates. We observed most USP39 stably integrated into the tri-snRNP complex and there is almost no free nuclear protein. More importantly, the relative abundance of tri-snRNP spliceosome complex was impaired in USP39-depleted cells. As previous reports indicated, USP39 is a regulator of tri-snRNP stability and its depletion decreased the levels of assembled U4/U6.U5 complexes.