Project description:The ubiquitin-specific protease 22 (USP22) is an oncogene and its expression is upregulated in many types of cancer. In the nucleus, USP22 functions as one subunit of the SAGA to regulate gene transcription. However, the genome-wide USP22 binding sites and its direct target genes are yet clear. In this study, we characterized the potential genomic binding sites of UPS22 and GCN5 by ChIP-seq using specific antibodies in HeLa cells. There were 408 overlapping putative target genes bound by both USP22 and GCN5. Motif analysis showed that the sequences bound by USP22 and GCN5 shared two common motifs. Gene ontology (GO) and pathway analysis indicated that the genes targeted by USP22 and GCN5 were involved in different physiological processes and pathways. Further RNA-seq, GO and pathway analyses revealed that knockdown of UPS22 induced differential expression of many genes that participated in diverse physiological processes, such as metabolic process. Integration of ChIP-seq and RNA-seq data revealed that UPS22 bound to the promoters of 56 genes. These findings may provide new insights into the regulation of USP22 on gene expression during the development of cervical cancer.
Project description:Prss14/ST14 is a type II transmembrane serine protease which is reported to be overexpressed in many epithelial cancers and plays critical roles in cancer initiation, progression, and metastasis. Prss14/ST14 undergoes ectodomain shedding in response to various stimulus including serum, TGF-β, and PMA. The fate of the residual membrane anchored N-terminal fragment (NTF) remains unknown. We show that the membrane-bound remnant, which is resulted from PMA-induced ectodomain shedding mediated by tumor necrosis factor-a converting enzyme (TACE) is subjected to regulated intramembrane proteolysis (RIP). The signal peptide peptidase-like 2b (SPPL2b) is identified as the enzyme carrying out this RIP. After RIP, we demonstrate that the generated soluble Prss14/ST14 intracellular domain (EICD) translocates to the nucleus. The ability of cell invasion and migration is abolished in SPPL2b-knockdown cells and these are recovered by transfection of exogenous EICD (N55). Furthermore, EICD is able to activate transcription and this observation prompts us to investigate target genes of EICD using RNA-seq. Analysis of RNA-seq results using samples from multiple conditions and network analysis reveal the EICD target genes that are associated with migration, invasion, and EMT. Furthermore, N55-overexpressing cell lines show scattered phenotype and increased EMT markers expression. ER-negative breast cancer patients with high expression of FOS or MMP13, the target genes, and Prss14/ST14 show poor survival outcomes, suggesting these genes can be used for prognosis markers of ER negative breast cancer. In this study, we propose a new mechanism to facilitate the cancer cell migration, invasion, and EMT by transcriptional regulation of EICD generated by SPPL2b.