Inhibition of DKFZP564J0863 in pancreatic cancer cells leads to apoptosis and has synergistic effects with gemcitabine Free

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Background: Prognosis for patients with pancreatic carcinoma (PDAC) remains poor. Despite of increasing knowledge about the molecular basis of PDAC neither a specific marker for early diagnosis nor a target protein for a new therapeutic approach have been identified so far. In recent year’s gene expression profiling experiments have identified a large number of candidate genes for diagnosis and therapy. Within our gene expression profiling experiments on microdissected PDAC and normal ductal cells we identified DKFZP564J0863 as overexpressed by more than a factor of six in pancreatic cancer. Interestingly, compared to primary normal tissue DKFZP564J0863 is highly expressed in pancreatic cancer cell lines making it suitable for further investigation. We were therefore interested to elucidate the role of DKFZP564J0863 in pancreatic cancer.
 Methods: Two siRNA molecules with different sequence were designed against DKFZP564J0863 and synthesized. MiaPaCa-2 cells were transfected with these siRNAs using Oligofectamine. The resulting knock-down of DKFZP564J0863 was analysed using quantitative RT-PCR. We also investigated induction of apoptosis using a FACS assay for AnnexinV binding and propidium iodide incorporation. Additionally, cells were treated with gemcitabine or 5-fluorouracil (5-FU), respectively.
 Results: Upon transfection of MiaPaCa-2 cells with either siRNA molecule we routinely observed a knock-down of DKFZP564J0863 mRNA of greater than 75%. Treatment of cells with the siRNA molecules induced the fraction of cells positive for AnnexinV binding by the factor of two. Administration of either gemicitabine or 5-FU enhanced the cell fraction positive for AnnexinV by an additional factor of two, resulting in a quadruplication of cells positive for AnnexinV.
 Conclusion: Expression of DKFZP564J0863, a member of the family of Guanylate-binding proteins, might be essential for cell survival. Inhibition of DKFZP564J0863 might be an interesting approach for the therapy of pancreatic cancer, especially with a multimodal treatment including gemcitabine or 5-FU. We are now in the process to characterize DKFZP564J0863 function in pancreatic cancer in more detail.