Effect of DUSP11 modulation on gemcitabine sensitivity in pancreatic ductal adenocarcinoma cell lines

Author(s)

Verena Silva Santos

• Document type: Master's Dissertation
• Press: Ribeirão Preto.
• Institution: Universidade de São Paulo (USP). Faculdade de Medicina de Ribeirão Preto (PCARP/BC)
• Defense date: 2018-11-30

Examining board members

Vanessa da Silva Silveira; Eduardo Moraes Rego Reis; Wilson Araújo da Silva Junior

• Advisor: Vanessa da Silva Silveira

Abstract

Pancreatic ductal adenocarcinoma (PDAC) has a highly malignant potential, with poor prognosis in most diagnoses. Gemcitabine is the chemotherapeutic agent most used in the treatment of PDAC. However, even presenting better therapeutic response over other drugs, ADP cells exhibit resistance that hinders treatment efficiency. Activation of the KRAS oncogene represents one of the major genetic alterations that triggers specific signaling pathways essential for tumor progression and chemoresistance, especially mediated by mitogen-activated protein kinases (MAPKs). MAPKs coordinate complex signaling networks and are precisely regulated by feedback mechanisms exerted by the activity of protein phosphatases. One of the major classes of phosphatases involved is represented by dualspecificity protein phosphatases (DUSPs) and their role in PDAC cells remainsto be elucidated. Our study group demonstrated that DUSP11 knockout on PDAC cell lines by CRISPR-Cas9 phenotypic screening increased the response to gemcitabine, indicating that DUSP11 may mediate the chemoresistance process. PDAC cell lines show increased expression of DUSP11 relative to tumor-free pancreatic tissue samples. Their inhibition was performed using CRISPR / Cas9 technology. Analyzes of DUSP11 gene expression in human PDAC samples and association with survival were performed with the aid of in silico platforms. Cell proliferation assays, apoptosis, clonogenic capacity, cell migration and cell invasion were performed in the MIA PaCa-2 cell line. It was observed that DUSP11 is more expressed in ADP samples, according to tumor staging, associating with a lower survival rate of the patients. In the MIA PaCa-2 cell line, inhibition of DUSP11 in combination with gemcitabine treatment has been observed to reduce the proliferative capacity of cells; increased rates of apoptosis and decreased the ability of cells to form colonies. However, no reduction in the migratory and invasive capacity of these cells was observed. The results suggest that DUSP11 acts in the modulation of processes involved in progression and chemoresistance but may not be involved in the control of processes that lead to the development of metastasis. (AU)

• FAPESP's process: 16/23013-9 - Effect of dual specificity phosphatases modulation and sensitization to gemcitabine
• Grantee: Verena Silva Santos
• Support Opportunities: Scholarships in Brazil - Master