Research of novel treatment for childhood leukemia by disrupting the chimeric gene function using RNAi

染色体易位是导致儿童白血病和其他恶性疾病的基因组突变之一。由于染色体易位产生的嵌合mRNA促进了肿瘤的发生，因此使用RNAi破坏嵌合mRNA的功能被认为是儿童白血病和恶性疾病的可能治疗方法。然而，在某些情况下，易位断裂点的基因组结构尚未明确，这阻碍了利用RNAi进行新治疗的发展。本研究以t（15;17）（q13;q11）和t（2;2）（q21;q35）的急性髓细胞白血病（AML）细胞和滑膜肉瘤细胞为研究对象，分析了染色体易位产生的嵌合mRNA的分子结构。建立了AML细胞cDNA文库，筛选出含有易位断裂点的噬菌体。在滑膜肉瘤细胞的情况下，由于作为横纹肌肉瘤的常见断裂点的PAX 3基因位于断裂点的一个位点上，因此使用3 ′-RACE（cDNA末端的快速扩增）方法分析对应物。这些结果为利用RNAi技术阻断嵌合体mRNA提供了新的治疗策略。将分析破坏这些嵌合mRNA的RNAi的作用。

Chromosome translocations are one of the genomic mutations which are responsible for childhood leukemia and other malignant disorders. Because chromosome translocation generates chimeric mRNA which promote the carcinogenesis, the disruption of chimeric mRNA function using RNAi is thought to be possible therapeutic approach for childhood leukemia and malignant disorders. However, genomic structure of translocation breakpoint have not been clarified in some cases, which hampers the development of novel therapy using RNAi. In this Research, to establish this new therapeutic strategy, the molecular structure of chimeric mRNA generated by chromosomal translocation was analyzed.We analyzed the translocation breakpoint of acute myelocytic leukemia (AML) cells with t(15;17)(q13;q11), and synovial sarcoma cells with t(2;2)(q21;q35). A cDNA library derived from AML cells were established and bacteriophages containing translocation breakpoint have been selected. In the case of synovial sarcoma cells, because PAX3 gene which is common breakpoint of rhabdomyosarcoma is located on the one site of breakpoints, counterpart have been analyzed using 3'-RACE (rapid amplification of cDNA end) method. Candiate product containing chimeric mRNA have been amplified.These results promote the novel therapeutic strategy disrupting chimeric mRNA using RNAi. The effect of RNAi which disrupt these chimeric mRNA will be analyzed.