TY - JOUR T1 - Cleavage of the Ewing Tumour-specific <em>EWSR1-FLI1</em> mRNA by Hammerhead Ribozymes JF - Anticancer Research JO - Anticancer Res SP - 1901 LP - 1908 VL - 29 IS - 6 AU - REGINA HÜHN AU - MARTIN S. STAEGE AU - MANUELA HESSE AU - BEATE LIEBIG AU - STEFAN E.G. BURDACH Y1 - 2009/06/01 UR - http://ar.iiarjournals.org/content/29/6/1901.abstract N2 - Background: Ewing family tumours (EFT) are the second most common bone tumours in children and adolescents. In the majority of EFT, EWSR1-FLI1 (Ewing sarcoma breakpoint region 1-Friend leukaemia virus integration 1) fusion proteins can be detected and EWSR1-FLI1 substantially contributes to the malignant phenotype of EFT. Therefore, inactivation of EWSR1-FLI1 is an interesting strategy for EFT therapy. Materials and Methods: A ribozyme with specificity for EWSR1-FLI1 was developed and the activity in vitro was investigated. Synthetic RNAs corresponding to EWSR1-FLI1 were used as substrates. In addition, the total RNA from EFT cells was used as substrate and the rapid amplification of cDNA ends method for the detection of the cleavage products was used. Results: The ribozyme cleaved the synthetic RNA in a sequence specific manner with high efficiency in vitro. Furthermore, the expected cleavage products were detected after digestion of the total cellular RNA with this ribozyme. A point mutation in the catalytic centre of the ribozyme abolished enzymatic activity. Conclusion: The RNA corresponding to EWSR1-FLI1 is accessible for ribozyme mediated inactivation and ribozymes are able to cleave EWSR1-FLI1 specific RNA in the presence of a high background of normal cellular RNAs. ER -