Generation of drug-resistant cell lines as a model to study pancreatic cancer

• Autor(a) principal: Grenho, Inês Filipa Acácio
• Data de Publicação: 2021
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositórios Científicos de Acesso Aberto de Portugal (RCAAP)
• Texto Completo: http://hdl.handle.net/10400.1/19776
• topic: Pancreatic cancer; Gemcitabine; Drug-resistance; Resistance mechanisms; TRIB2; TRIB3

Pancreatic cancer (PC) is among the most aggressive cancers in the world, characterized by an extremely high mortality/incidence ratio. Besides its aggressiveness, PC is usually diagnosed in an advanced and metastatic stage, which limits the treatment options available. Most of these tumors are unresectable by surgery, thus chemotherapy remains the only option available for treatment. However, a majority of these patients relapse within months and have a recurrence of the disease, usually more aggressive and no longer sensitive to the initial treatment. The major responsible for this relapse is the development of acquired therapy resistance. Our work focused on generating cell lines resistant to the current first line chemotherapy drug, Gemcitabine, and on their characterization. This allowed us to generate tools that will be crucial to unveil the mechanism driving acquired resistance in PC. Previous studies from our group and others demonstrated an association between the expression profiles of TRIBBLES pseudokinases and drug resistant phenotypes in other cancers. We evaluated the sensitivity of the generated cell lines to Gemcitabine and characterized them in terms of migration ability, cell death rate under stress and the expression of TRIBBLES proteins and EMT markers. Our results show that we successfully generated Gemcitabine-resistant cell lines, and that these cell lines are phenotypically different from the sensitive ones, showing fibroblastic-like features. Furthermore, we observed a reversible phenotypic switch when these cells undergo Gemcitabine treatment. They show different migration ability and increased mRNA expression of EMT markers, a hallmark of the epithelial-to-mesenchymal transition process. Moreover, in the resistant cells we observed higher TRIB2 protein expression levels and a decrease in the TRIB3 protein expression, compared with the sensitive cell lines. Overall, the phenotype associated with the resistant cells is concordant with drug resistance development by chronic Gemcitabine exposure.