Project description:Intestinal epithelial cells (IECs) were isolated from the colon of Villin-CreERT2, Rnf20-flox and Rnf40-flox mice two weeks upon the Tamoxifen-induced, intestinal knockout of Rnf20 and Rnf40. RNA was isolated from snap-frozen IECs to perform mRNA-seq.
Project description:Breast cancer (BC), the most frequent tumor entity in women globally, shows a high therapeutic response in early and non-metastatic stages. However, triple-negative BC (TNBC), enriched with cancer stem cells (CSCs), presents significant challenges due to its chemoresistant and metastatic nature. Ubiquitin Specific Proteinase 22 (USP22) has emerged as a key player in promoting CSC functions, contributing to resistance to conventional therapies, tumor relapse, metastasis, and poor survival across various cancers, including BC. The specific role of USP22 in TNBC, however, remains underexplored. In this study, we employed the MMTV-cre, Usp22fl/fl transgenic mouse model to investigate USP22's influence on stem cell-like properties in mammary tissue. High-throughput transcriptomic analyses, combined with publicly available patient data and TNBC culture models, were utilized to elucidate USP22's role in CSC characteristics of TNBC. Our findings reveal that USP22 enhances CSC properties and drug tolerance by supporting oxidative phosphorylation, a key factor in the poor response to conventional therapies in aggressive BC subtypes. The study uncovers a novel tumor-supportive role of USP22 in sustaining cellular respiration, which contributes to the drug-tolerant behavior of HER2+-BC and TNBC cells. This highlights USP22 as a potential therapeutic target, offering new avenues to optimize standard treatments and address the aggressiveness of these malignancies.
Project description:Dynamic control of ubiquitination by deubiquitinating enzymes is essential for almost all biological processes. Ubiquitin-specific peptidase 22 (USP22) is part of the SAGA complex and catalyzes the removal of monoubiquitination from histone H2B, thereby regulating gene transcription. However, novel roles for USP22 have recently emerged, such as tumor development and cell death. Apart from apoptosis, the relevance of USP22 in other programmed cell death pathways still remains unclear. Here, we describe a novel role for USP22 in controlling necroptotic cell death in a variety of tumor cell lines. Loss of USP22 expression significantly delays TNF/Smac mimetic/zVAD.fmk (TBZ)-induced necroptosis, without affecting TNF-mediated NF-B activation or extrinsic apoptosis. Mass-spectrometric ubiquitin remnant profiling identified lysine 518 of Receptor-interacting protein kinase 3 (RIPK3) as USP22-dependent ubiquitination target during necroptosis induction. Mutation of K518 in RIPK3 reduced necroptosisassociated RIPK3 ubiquitination and amplified necrosome formation and necroptotic cell death. In conclusion, we identify a novel role of USP22 in necroptosis and further elucidate the relevance of ubiquitination as crucial regulator of necroptotic cell death.