Study of RNA-binding protein networks in colorectal cancer cells

• Autor(a) principal: Coelho, Alexandre Rodrigues
• Data de Publicação: 2021
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10400.1/19243
• topic: Colorectal cancer; RNA-binding protein; Intestinal stem cells; TIMELESS; ASPM; ZBTB16; Domínio/Área Científica::Ciências Médicas::Outras Ciências Médicas

Colorectal cancer (CRC) is one of the leading cancer-related deaths in the world, causing the death of almost 1 million people every year, thus highlighting the need for better prognostic biomarkers and reliable therapeutic targets. It is increasingly evident that RBPs are major players in stem cell biology and carcinogenesis, namely in CRC, and have the potential to regulate several cancer-related phenotypes when dysregulates. Therefore, we aimed at identifying new RBPs with a functional impact in the context of CRC. An in silico approach led us to three potential stemness-related RBPs: ASPM, TIMELESS and ZBTB16. The characterization of a cohort of human CRC cases showed that ASPM and ZBTB16 were preferentially overexpressed in tumoral tissue, whereas TIMELESS was expressed at low and high levels in the same proportion of cases. However, an association with a MSS status was found, indicating that TIMELESS might have a predictive prognostic value. TIMELESS knockdown induced several functional changes in CRC cell lines, some in a cell line-specific manner. TIMELESS depletion led to a prominent reduction of cells in S phase and sensitized them for apoptosis or necrosis which was further amplified by the exposure to the chemotherapeutic agent 5-FU. Furthermore, we observed that TIMELESS expression was restricted to the crypt base in normal tissue and the expression of several known ISC markers was altered upon TIMELESS removal. The phenotypic alterations also occurred at the level of mRNA metabolism in SW480 cells through a reduction of P-body aggregates. Our results show that TIMELESS might be implicated in key tumorigenic processes, such as promotion of cell proliferation and cell death avoidance. This work highlights the relevance of putative RBPs in CRC and the understanding of their functional impact opens an avenue for novel cancer therapies.