Characterization of oncogenic FGFR3-TACC3 fusion gene in glioblastoma

项目摘要 融合基因是许多癌症中常见的染色体异常，可用作 临床实践中的预后标志物和药物靶点。通过使用整个转录组 测序，我们和其他人[1，2]在胶质母细胞瘤中发现了FGFR3-TACC3融合 (GBM)，复发率高达8.3%。核聚变是由一次串联复制事件引起的 4p16.3在体外促进细胞增殖，在体内促进肿瘤进展。的过度表达 星形胶质细胞融合导致细胞非整倍体[1]，然而促进异常的机制 染色体分离仍有待阐明。FGFR3-TACC3融合阳性细胞 对MEK抑制剂U0126或PAN FGFR抑制剂PD173074表现出更高的敏感性，但 对一线GBM化疗药物替莫唑胺(TMZ)的耐药性更强。因此，我们的 研究已经确定了一种新的GBM基因改变，这种改变对至少两个主要 这种致命疾病的特点是：基因组不稳定和对化疗耐药。最近 报告显示，FGFR3-TACC3融合也存在于膀胱癌[3]。因此， 这一新发现的基因事件的意义可能是广泛的。我们寻求进一步 鉴定这个新的癌基因FGFR3-TACC3。我们假设FGFR3-TACC3 融合蛋白是一种关键的遗传变异，它显著改变了信号通路 在胶质瘤的发展和进展过程中，导致了基底膜的特征。我们计划 通过进行实验来验证我们的假设，这些实验将确定关键的磷酸化 融合内促进肿瘤发展的位点和结构域，以确定 融合对替莫唑胺治疗耐药的分子机制，以确定 融合促进异常染色体分离的机制，最终 确定现有药物抑制物治疗融合的疗效 肿瘤。我们将使用体外和体内两种方法来回答这些问题。

Project Summary Fusion genes are common chromosomal aberrations in many cancers, and can be used as prognostic markers and drug targets in clinical practice. By using whole transcriptome sequencing, we and others [1, 2] have discovered FGFR3-TACC3 fusions in glioblastoma (GBM) at a recurrence rate of up to 8.3%. The fusion, caused by a tandem duplication event on 4p16.3, promoted cell proliferation in vitro and tumor progression in vivo. Overexpression of the fusion in astrocytes lead to cellular aneuploidy [1], however the mechanisms facilitating aberrant chromosomal segregation remain to be elucidated. FGFR3-TACC3 fusion positive cells exhibited higher sensitivity to the MEK inhibitor U0126 or pan FGFR inhibitor PD173074 but were more resistant to the frontline GBM chemotherapy drug, Temozolomide (TMZ). Thus, our studies have identified a novel genetic alteration in GBM that is critical for at least two major hallmarks of this deadly disease: genomic instability and resistance to chemotherapy. A recent report showed that the FGFR3-TACC3 fusion also occurs in bladder cancer [3]. Thus, the significance of this newly recognized genetic event is likely broad. We seek to further characterize this novel FGFR3-TACC3 oncogene. We hypothesize that the FGFR3-TACC3 fusion protein is a key genetic aberration that significantly modifies the signaling pathways during glioma development and progression contributing to the hallmarks of GBM. We plan to test our hypothesis by performing experiments that will determine the critical phosphorylation sites and domains within the fusion that promote tumor development, to determine the molecular mechanisms by which the fusion is resistant to temozolomide treatment, to determine the mechanisms by which the fusion promotes abnormal chromosomal segregation, and finally to determine the efficacy of current pharmacological inhibitors in treating fusion containing tumors. We will use both in vitro and in vivo approaches to answer these questions.