Abstract #4661: Inhibition of MIF leads to cell cycle arrest and apoptosis in pancreatic cancer cells

Introduction: Pancreatic ductal adenocarcinoma (PDAC) remains an important cause of malignancy-related death and is the eighth most common cancer with the lowest overall 5-year relative survival rate. Gene expression profiling of PDAC compared to normal ductal tissue revealed an over expression of the macrophage migration inhibitory factor (MIF) a lymphokine involved in cell-mediated immunity and inflammation, as well as in the regulation of cellular signal transduction. Therefore we were interested in the role of MIF in pancreatic cancer cells. Methods: Endogenous MIF expression was silenced by treatment of pancreatic cancer cell lines using two independent MIF siRNAs. The expression of MIF RNA and Protein after siRNA treatment was investigated using quantitative RT-PCR and Western blot. Cell cycle and Apoptosis were analysed using fluorescence activated cell sorting (FACS) using propidium iodide and AnnexinV. Cellular proliferation was monitored using a Wst-1 assay. Furthermore changes in phosphorylation of key signalling proteins were investigated. Results: Transfection of MiaPaCa-2 cells and PANC1 cells with MIF siRNA resulted in a reduction of MIF RNA and protein levels by more than 85%. After treatment we observed an inhibition of cellular proliferation accompanied with induction of Apoptosis. Cell Cycle analysis revealed an inhibition at the G2/M transition. Analysis of the phosphorylation state of AKT a central signal transduction kinase showed a markedly increase of the phosphorylation at the Thr308 residue. Conclusions: Using post transcriptional silencing with small interfering RNAs we could show, that MIF acts as an autocrine growth factor involved in cell cycle progression. Since MIF is a secreted protein a therapy directed against MIF or its receptor might lead to a significant growth reduction of pancreatic ductal adenocarcinoma.

Citation Information: In: Proc Am Assoc Cancer Res; 2009 Apr 18-22; Denver, CO. Philadelphia (PA): AACR; 2009. Abstract nr 4661.