EWS-Fli1, a fusion gene resulting from the chromosomal translocation t(11;22, q24;q12), encodes a transcriptional activator, promotes cellular transformation, and is often found in Ewing sarcoma and primitive neuroectodermal tumor. The Aurora A and Aurora B kinases belong to a highly conserved family of serine/threonine protein kinases, are tightly regulated during the cell cycle, and are overexpressed in many carcinomas. Because the relationship between the Aurora A and/or Aurora B genes and the EWS-Fli1 fusion gene is unknown, we investigated the regulatory mechanism(s) by which Aurora kinases are controlled. Knockdown of EWS-Fli1 by small interfering RNA reduced mRNA levels not only of EWS-Fli1 but also of Aurora A and Aurora B. Luciferase assay using Aurora A and Aurora B promoters showed up-regulated activities compared with those of an empty vector. Experiments with deletion and point mutants showed positive regulatory Ets-binding sites located À84 and À71 bp upstream of the transcription initiation sites in Aurora A and Aurora B, respectively. Moreover, chromatin immunoprecipitation assay revealed that EWS-Fli1 gene products interact with both the Aurora A and Aurora B promoters. These results strongly suggest that the mitotic kinases Aurora A and Aurora B are regulated by EWS-Fli1 fusion protein in Ewing sarcoma cells.

Heterozygous missense mutations of transient receptor potential vanilloid 4 channel (TRPV4) cause a spectrum of skeletal disorders, including brachyolmia, spondylometaphyseal dysplasia Kozlowski type, metatropic dysplasia, parastremmatic dysplasia, and spondyloepimetaphyseal dysplasia Maroteaux type. Similarly, heterozygous missense mutations of TRPV4 cause a spectrum of peripheral neuropathy, including hereditary motor and sensory neuropathy type IIC, congenital spinal muscular atrophy, and scapuloperoneal spinal muscular atrophy. There are no apparent differences in the amino acid positions affected or type of change predicted by the TRPV4 mutations responsible for the two disease spectrums; nevertheless, no fundamental phenotypic overlap has been shown between the two spectrums. Here, we report on three patients who had both skeletal dysplasia and peripheral neuropathy caused by heterozygous TRPV4 missense mutations. The skeletal and neurologic phenotypes of these patients covered the wide spectrum of reported TRPV4-pathies (disease caused by TRPV4 mutations). The molecular data are complementary, proving that "neuropathic" mutations can cause skeletal dysplasia but also the "skeletopathic" mutations can lead to neuropathies. Our findings suggest that pathogenic mechanisms of TRPV4-pathies in skeletal and nervous systems are not always mutually exclusive and provide further evidence that there is no clear genotype-phenotype correlation for either spectrum. Co-occurrence of skeletal dysplasia and degenerative neuropathy should be kept in mind in clinical practice including diagnostic testing, surgical evaluation, and genetic counseling.

No abstract

No abstract

The EWS/Fli-1 fusion gene, a product of the translocation t (11;22, q24;q12), is detected in 85% of Ewing sarcomas and primitive neuroectodermal tumors. It is thought to be a transcriptional activator that plays a significant role in tumorigenesis. In this study, we developed a novel EWS/Fli-1 blockade system using RNA interference and tested its application for inhibiting the proliferation of Ewing sarcoma cells in vitro and the treatment of mouse tumor xenografts in vivo. We designed and synthesized a small interfering RNA (siRNA) possessing an aromatic compound at the 3 0 -end targeting the breakpoint of EWS/Fli-1. As this sequence is present only in tumor cells, it is a potentially relevant target. We found that the siRNA targeting EWS/Fli-1 significantly suppressed the expression of EWS/Fli-1 protein sequence specifically and also reduced the expression of c-Myc protein in Ewing sarcoma cells. We further demonstrated that inhibition of EWS/Fli-1 expression efficiently inhibited the proliferation of the transfected cells but did not induce apoptotic cell death. In addition, the siRNA possessing the aromatic compound at the 3 0 -end was more resistant to nucleolytic degradation than the unmodified siRNA. Administration of the siRNA with atelocollagen significantly inhibited the tumor growth of TC-135, a Ewing sarcoma cell line, which had been subcutaneously xenografted into mice. Moreover, modification of the 3 0 -end with an aromatic compound improved its efficiency in vivo. Our data suggest that specific downregulation of EWS/Fli-1 by RNA interference is a possible approach for the treatment of Ewing sarcoma.The Ewing sarcoma family of tumors (ESFTs) is a group of highly malignant neoplasms that most often affect children and young adults in the first two decades of life. It is the second most common malignant bone tumor and accounts for approximately 10% of all primary bone tumors. Despite aggressive treatment strategies (chemotherapy, radiation therapy and surgery), the long-term disease-free survival rate of patients with ES is still disappointingly low, particularly in poor-risk patients with metastasis. Therefore, identification of new therapeutic targets is urgently needed.The EWS/Fli-1 fusion gene, a product of the translocation t(11;22, q24;q12), is detected in 85% of ESs and primitive neuroectodermal tumors. The EWS/Fli-1 translocation is formed by the N-terminal domain of the RNA-binding protein EWS and the DNA-binding domain of the ETS family transcriptional factor Fli-1. Identification of several breakpoints for both EWS and Fli-1 has demonstrated that the EWS/Fli-1 fusion genes are heterogeneous. Breakpoints of Type 1 (Exon 7 of EWS/Exon 6 of Fli-1) and Type 2 (Exon 7 of EWS/Exon 5 of Fli-1) are most commonly detected in affected patients. [1][2][3] We have reported that the EWS/Fli-1 fusion protein may be a transcriptional activator that plays a significant role in the tumorigenesis of ESFTs. [4][5][6][7] Although substantial studies have reported that antagonism of the EWS fusion gene reduces...