Dados do Resumo

Título

EXPLORING THE ROLE OF PrPC IN CD44 TRAFFICKING: INSIGHTS INTO GLIOBLASTOMA STEM-LIKE CELLS

Introdução

Glioblastoma (GBM) is the most aggressive form of glioma, with a dismal survival rate of just 1 to 2 years and a high incidence of recurrence. The heterogeneity of GBM highlights the importance of understanding glioblastoma stem-like cells (GSCs), a subpopulation crucial for tumor maintenance, invasion, and drug resistance. To better understand GBM and its interaction with the tumor microenvironment, it is essential to investigate the key proteins that orchestrate GSCs biology. One such key player is the prion protein (PrPC), a GPI-anchored glycoprotein located on membrane microdomains that functions as a scaffold protein recruiting ligands to facilitate intracellular signal transduction. Another player is CD44, a transmembrane protein involved in adhesion and migration and serving as a biomarker for tumor stem cells.

Objetivo

Given that both proteins are implicated in GSCs biology and that our group showed their co-localization in lipid rafts, the main goal of this study is to evaluate the role of PrPC in CD44 trafficking.

Métodos

We conducted overlay, pull-down and co-immunoprecipitation assays to confirm the interaction between PrPC and CD44 both in vitro. Additionally, qPCR, immunohistochemistry and Western blotting analysis were performed to assess the expression and localization of CD44 and endocytic pathway biomarkers in distinct GBM cells with differential expression of PrPC (wild-type and knockout cells). Copper internalization assays were also conducted to analyze the influence of PrPC’ on CD44 membrane trafficking.

Resultados

Our findings demonstrate that PrPC interacts with CD44, significantly modulating its expression and localization. Specifically, CD44 was downregulated in PrPC knockout cells and showed reduced membrane expression with accumulation in intracellular compartments, suggesting disruption in its trafficking. Furthermore, PrPC modulates the expression of several endocytic biomarkers indicating its involvement in protein sorting and trafficking. Remarkably, CD44’s internalization via copper is impaired in the absence of PrPC.

Conclusões

These results highlight the critical role of PrPC in CD44 trafficking within GSCs and additional experiments are required to deepen our understanding of GBM biology. Ultimately, this research could contribute to developing new treatments and also improve the quality of life of GBM patients.

Financiador do resumo

Fundação de Amparo à Pesquisa do Estado de São Paulo

Palavras Chave

Glioblastoma; CD44; Trafficking