Détection, annotation fonctionnelle et régulation des isoformes de l'épissage alternatif associées au cancer de l'ovaire

Abstract: Cancer cells modify their gene expression pattern to promote tumor growth. Unfortunately, current research focuses almost exclusively on global gene expression changes, without taking into account the fact that the majority of genes produce multiple alternative splicing variants, which potentially code for proteins of different functions In fact, the main reason splicing isoforms are still studied on a gene by gene basis is because the high sequence similarity and complexity of mRNA isoforms make it very difficult to detect and quantify them. To overcome this difficulty, we developed a high-throughput methodology to accurately quantify splicing isoforms. This methodology has been applied in this thesis to generate evidence supporting a causal role for splicing isoforrns in the tumorigenesis of solid tumors. A few years ago, genome-wide bioinformatics predictions, and some experimental validations in human tissues, suggested the existence of cancer-specific splicing isoforms. However, these conclusions may be simply explained by the cellular heterogeneity of tumor. In fact, it is well established that alternative splicing is a cell type-specific process. To address this, we microdissected cancer tissues and demonstrated that some splicing isoforms are truly cancer-associated and independent of tumor cell type content. Surprisingly, the most interesting changes were found in the "normal" stromal cells surrounding the tumor and not within the cancer cells. Our analysis of splicing-factor expression changes using the same tissue set allowed us to confirm that these splicing shifts were not a random process, but rather part of a defined splicing program promoting tumor development. To evaluate the functional contribution of splicing isoforms, we developed molecular tools that modulate splicing of endogenous targets in cancer cell lines. We used these tools to decipher the pro-cancer properties of cancer-associated splicing isoforms using in vitro assays. Overall, this work demonstrated the contribution of splicing isoforms in solid tumor development.

Name thesis:degree_name

Ph. D.

Level thesis:degree_level

Doctorat

Discipline thesis:degree_discipline

Biochimie

Grantor dc:publisher

Université de Sherbrooke

Year dc:date.issued

2012

Author dc:creator

• Brosseau, Jean-Philippe

Advisor dc:contributor.advisor

• Perreault, Jean-Pierre

• Microenvironnement
• Épissage alternatif
• Microdissection au laser
• SiRNA
• Analyse de l'ARN
• PCR en temps réel à haut débit
• Cancer de l'ovaire

Language dc:language.iso

fr

Handle dc:identifier.uri

http://hdl.handle.net/11143/6652

OAI identifier oai:identifier

oai:usherbrooke.scholaris.ca:11143/6652