Synergistische Effekte von Taurolidin und TRAIL bei der Apoptoseinduktion in TRAIL resistenten Ösophaguskarzinomzellen

Abstract

Background: The treatment of choice for esophageal cancer is considered surgical resection, but a median survival of around 20 months after treatment is still discouraging. The value of adjuvant or neoadjuvant radiation or chemotherapy is limited and to date benefits have only been described for certain tumor stages. Therefore new therapeutic options are to be found. Methods: As alternative chemotherapeutics, we tested the antibiotic Taurolidine (TRD) on KYSE 270 human esophageal carcinoma cells alone and in combination with rhTRAIL (TNF related apoptosis-inducing ligand). Viability, apoptosis and necrosis were visualized by TUNEL-Assay and quantitated by FACS analysis. Gene expression was analysed by RNA-Microarray. Results: The most effective concentration of TRD as single substance (250 μmol/l) induced apoptosis to a maximum of 40 % after 12 h dose dependently, leaving 4 % viable cells after 48 h; by comparison, rhTRAIL did not have a significant effect. The combination of both substances could double the effect of TRD alone. Gene expression profiling revealed that TRD downregulated endogenous TRAIL, TNFRSF1A, TRADD, TNFRSF1B, TNFRSF21, FADD, as well as MAP2K4, JAK2 and Bcl2, Bcl2l1, APAF1, and Caspase 3. TNFRSF25, cytochrome-c, caspases 1, 8, 9, JUN, GADD45A, and NFKBIA were upregulated. TRAIL reduced endogenous TRAIL, Bcl2l1, and caspase 1 expression. BIRC2, BIRC3, TNFAIP3, and NFKBIA were upregulated. The combined substances upregulated endogenous TRAIL, NFKBIA, and JUN, whereas DFFA and TRAF3 were downregulated. Conclusion: We conclude that TRD overcomes TRAIL resistance in KYSE 270 cells. Synergistic effects are dependent on the same and on distinct apoptotic pathways which, jointly triggered, result in an amplified response. Several apoptotic pathways, including the TNF-receptor associated and the mitochondrial pathway, were differentially regulated by the substances. Additionally transcription factors were influenced, NFKB in particular. Taking into consideration that the non toxic TRD could reduce rhTRAIL toxicity and dose, combined therapy with TRD and rhTRAIL may offer new options for treatment in esophageal cancer.