Charakterisierung neuer Zielgene im Pankreaskarzinom

Pancreatic ductal adenocarcinoma is one of the deadliest and most difficult to treat cancer diseases in the western world. Due to the restricted diagnostic possibilities and few effective drugs, the treatment is only in rare cases successful. Therefore it is important to identify novel target genes for therapeutic and diagnostic approaches. A shRNA-screen was performed to identify new candidate genes with high biological relevance in ductal adenocarcinoma of the pancreas. The herein established candidates were selected with regard to the potential susceptibility to treatment with small inhibitory molecules. SMC2 and USP5 could be identified as potential novel target genes in pancreatic cancer. So far, there are no reports concerning an influence of these genes on the development and progression of pancreatic cancer in the literature. In this study, both genes were analyzed for their function and involved pathways in pancreatic cancer. For the characterization of the genes, gene expression was quantified using qRT-PCR in primary tissues and different tumor cell lines. After transient knockdown with independent siRNAs for each gene, functional assays were performed for viability, cell proliferation and migration. Additionally, cell cycle analyses were performed to elucidate involved cellular pathways. To identify the involved pathways individually for both genes, western blot analyses were performed. Furthermore, lentivirally transduced, stable shRNA-clones were generated to collect in vivo data in xenograft mouse models. Both genes are significantly overexpressed in in human pancreatic cancer tissues. The induced knockdown in both cases led to a reduction in viability and proliferation and induced apoptotic cascades. This study identified SMC2 as a new modulator of the WNT-signaling pathway and as being regulated by WNT5A. By contrast, USP5 is involved in ubiquitination and stabilizes p27/CDKN1B in TP53 mutated pancreatic cancer cells. Based on previous studies and the herein elaborated data, it can be concluded that the novel target genes SMC2 and USP5 play important roles in growth and survival of pancreatic cancer cells. Both genes provide ideal conditions for the development of therapeutic approaches with small inhibitory molecules to fight cancer.