Simultaneous gene-inhibtion of Survivin, XIAP and Bcl-2 re-sensitises pancreatic cancer cell line MIA PaCa-2 to apoptosis

Abstract

Pancreatic cancer (PDAC) is an exceptionally devastating and incurable disease, the treatment of which has largely been unsuccessful due to higher resistance of pancreatic tumor cells to oncologic treatment. The last 10 years, many investigations were on the way to get insights into the details of drug resistance mechanisms of PDAC cells. Recent publications emphasize especially defects of the mitochondrial pathway of apoptosis signalling for the failure of oncologic treatment. Because of this, those defects came into the interest of clinicians as possible targets for new therapeutic approaches.

However, there are numerous and sequential defects in the course of the cell death pathway. Therefore defects might act redundantly in inhibiting physiologic signal transduction. Because of this we followed a new approach and aimed to simultaneous inhibit expression of several overexpressed, anti-apoptotic members of the mitochondrial cell death pathway to normalize the information flow. Simultaneous transfection of siRNAs against Bcl-2, XIAP and Survivin showed knock down of the target genes. The silencing was validated by RT-PCR and Western Blot. Quantification of cell death was achieved with flow cytometrie and by caspase assay.

This is to our knowledge the first report on simultaneous gene inhibition in the apoptosis pathway. We could show a significant re-sensibilisation of signal transduction in MIA PaCa-2 cells with an additive effect by simultaneous inhibition compared to single transfection of target siRNA.

Robert Gruetzmann and Christian Pilarsky share the senior authorship for this work