Molecular and functional characterization of USP2 gene in pediatric medulloblastoma groups 3 and 4

Author(s)

Jonas José da Silva

• Document type: Master's Dissertation
• Press: Ribeirão Preto.
• Institution: Universidade de São Paulo (USP). Faculdade de Medicina de Ribeirão Preto (PCARP/BC)
• Defense date: 2024-07-22

Examining board members

Carlos Alberto Scrideli; Angel Mauricio Castro Gamero; Andréia Machado Leopoldino

• Advisor: Carlos Alberto Scrideli; Pablo Shimaoka Chagas

Abstract

Medulloblastomas (MBs) are malignant tumors of embryonic origin, molecularly classified into: WNT (Wingless), SHH (Sonic Hedgehog), Group 3 (G3) MBs, and Group 4 (G4) MBs. G3 and G4 MBs have the worst prognosis due to their frequent metastasis at diagnosis and chemoresistance. Moreover, the identification of new therapeutic biomarkers is scarce for these patient groups. The USP2 gene, a putative effector of cross-talks with the NFκ-B nuclear factor pathway, has been reported as a potential biomarker of poor prognosis and/or therapeutic target in various cancers. However, there are no studies in the literature investigating the role of the USP2 gene in the oncobiology of G3 and G4 MBs. Thus, this study aimed to investigate the expression profile of the USP2 gene through in silico analyses using public databases (GSE85217) and ex vivo (tumor tissue) in a cohort of 56 pediatric patients by real-time PCR (qRT-PCR) in MB samples. Additionally, in vitro studies were conducted to promote the pharmacological inhibition of the USP2 protein using the compound ML364. Cell viability, clonogenicity, and Transwell assays were performed to evaluate cell viability, colony formation potential, migration, and invasion in D283 Med and USP-13 cell lines. Furthermore, drug combination studies with the chemotherapeutic cisplatin were carried out. Finally, pathway enrichment analyses were performed to verify the potential role of USP2 in the modulation of the NFκ-B pathway in MB. As a result, USP2 overexpression was identified in patients diagnosed with G3 and G4 MBs, and this expression profile was associated with the presence of metastases and poorer clinical outcomes. Additionally, USP2 overexpression showed potential in discriminating SHH/WNT MBs from G3/G4 MBs. Subsequently, treatment with the ML364 compound reduced the protein expression profile of USP2, as well as significantly decreased cell viability, migration, invasion, and colony formation potential in the G3 and G4 MB cell models used in this study. Together, our data suggest USP2 as a potential biomarker of poor prognosis and a therapeutic target for G3 and G4 MBs. However, future studies are necessary to further investigate these findings. (AU)

• FAPESP's process: 22/15919-9 - Molecular and functional characterization of USP2 in pediatric Medulloblastomas of Groups 3 and 4
• Grantee: Jonas José da Silva
• Support Opportunities: Scholarships in Brazil - Master