Exploring the Role of U34-tRNA Modifications on Pancreatic Ductal Adenocarcinoma

Details

Supervisors

Pierreux, Christophe

Faculty

Faculté de pharmacie et des sciences biomédicales

Degree label

Master [120] en sciences biomédicales, à finalité approfondie

Abstract

Pancreatic ductal adenocarcinoma (PDAC) ranks as the fourth deadliest cancer in the world, presenting a significant threat to patients. Its development is commonly linked to mutations in the KRAS gene and is exacerbated by pancreatitis. While extensive research has explored genetic mutations and transcriptional changes in pancreatic cancer, emerging evidence underscores the substantial impact of translational control on tumorigenesis. Notably, modifications of uridine-34 in tRNAs have been found to optimize the translation of HIF1A and SOX9 in melanoma and colorectal cancer, respectively, in a NAA codon-dependent manner. Increased translation of these proteins significantly influences the pathogenesis of these cancers. The main objective of this Master’s thesis was to demonstrate the implication of U34 tRNA modifications in pancreatic cancer. We used lentiviral transduction of shRNAs to reduce the abundance of U34-tRNA modifying proteins and assessed the consequences in vitro then in vivo. In vivo, we examined the impact of the silencing on the human pancreatic cancer cell line PANC-1. In vivo, we orthotopically grafted silenced murine KPC-792 cells, derived from pancreatic cancer, and analysed tumor growth in the pancreas. Our findings in PANC-1 cells revealed that upon downregulation of U34-tRNA modifying proteins, the translation of two well-described NAA-enriched mRNAs, coding for HIF1α and SOX9, were reduced. This reduction was observed using any of the four shRNAs used and was dependent on the silencing efficiency. In addition, we observed a notable decrease in cell numbers upon U34-tRNA modifying proteins silencing. To perform the in vivo studies, we selected and transduced the KPC-792 mouse cell line of pancreatic ductal adenocarcinoma with shRNAs targeting the murine mRNAs of U34-tRNA modifying proteins. These shRNA-transduced KPC-792 cells were orthotopically grafted in the pancreas of C57BL/6 mice to induce tumor formation. Preliminary results revealed a reduction in the size of tumor lesions developed from two different shRNA-transduced cells, in line with our observations of reduced PANC-1 cell numbers and published data. Altogether, these experiments suggest that U34-tRNA modifications may play a role in pancreatic cancer development.