Simultaneous gene silencing of Bcl-2, XIAP and Survivin re-sensitizes pancreatic cancer cells towards apoptosis

Abstract

BackgroundPancreatic ductal adenocarcinoma shows a distinct apoptosis resistance, which contributes significantly to the aggressive nature of this tumor and constrains the effectiveness of new therapeutic strategies. Apoptosis resistance is determined by the net balance of the cells pro-and anti-apoptotic "control mechanisms". Numerous dysregulated anti-apoptotic genes have been identified in pancreatic cancer and seem to contribute to the high anti-apoptotic buffering capacity. We aimed to compare the benefit of simultaneous gene silencing (SGS) of several candidate genes with conventional gene silencing of single genes.MethodsFrom literature search we identified the anti-apoptotic genes XIAP, Survivin and Bcl-2 as commonly upregulated in pancreatic cancer. We performed SGS and silencing of single candidate genes using siRNA molecules in two pancreatic cancer cell lines. Effectiveness of SGS was assessed by qRT-PCR and western blotting. Apoptosis induction was measured by flow cytometry and caspase activation.ResultsSimultaneous gene silencing reduced expression of the three target genes effectively. Compared to silencing of a single target or control, SGS of these genes resulted in a significant higher induction of apoptosis in pancreatic cancer cells.ConclusionsIn the present study we performed a subliminal silencing of different anti-apoptotic target genes simultaneously. Compared to silencing of single target genes, SGS had a significant higher impact on apoptosis induction in pancreatic cancer cells. Thereby, we give further evidence for the concept of an anti-apoptotic buffering capacity of pancreatic cancer cells.

Five Primary Human Pancreatic Adenocarcinoma Cell Lines Established by the Outgrowth Method

“…Dysregulation of genes associated with the intrinsic apoptotic pathway seem to play an important role in mediating this resistance to apoptosis [24,25]. We, therefore, evaluated the expression of several important anti-apoptotic genes of the intrinsic apoptosis pathway in our PaCaDD cell lines and in the established cell lines as controls.…”

Sevoflurane suppresses hypoxia-induced growth and metastasis of lung cancer cells via inhibiting hypoxia-inducible factor-1α

“…XIAP and survivin are the most potent caspase inhibitors of all of the IAPs. They can block the intrinsic and extrinsic apoptosis pathways via binding to caspases 3, 7, and 9 [25,26]. The expressions of XIAP and survivin are dramatically up-regulated in many cancers, resulting in a poor prognosis for cancer patients [27].…”

Molecular and Genetic Bases of Pancreatic Cancer

“…Mori et al reestablished TRAIL--induced apoptosis in TRAIL--resistant cells by exposure to FLIP antisense; moreover, the effect of TRAIL was enhanced by the combination of FLIP antisense and embelin, a small inhibitor of X--linked inhibitor of apoptosis protein (XIAP) [71]. Other data support the increase of the apoptosis--sensitization of TRAIL--resistant pancreatic carcinoma cells by down--regulation of c--FLIP and XIAP [72,73,74,75]. TRAIL has a great potential for clinical application and agonistic TRAIL receptors (TRAIL--R1/R2) are being investigated as therapeutic targets.…”