MOLECULAR CLONING OF A T(15;19) IN LUNG CANCER CELL LINE

这是Thao Dang医学博士的K08奖申请，旨在支持她五年的实验室培训，以进一步发展她在分子遗传学方面的技能，并探索新的致癌机制。恶性转化是遗传异常积累的结果。特异性染色体易位是造血恶性肿瘤中癌基因激活的主要机制，但在更常见的上皮肿瘤中尚未被描述。我们已经建立了一个细胞系，HCC2429，来自一种侵袭性转移性肺癌，除了染色体15q和19p之间的单个易位外，其核型正常。通过定位克隆，我们发现19号染色体上的断点位于Notch原癌基因家族成员Notch3起始位点上游约40kb处。这种易位与Notch3的大量过表达有关，支持了t（15;19）易位导致这种假定的细胞原癌基因解除调控的假设。此外，我们还在一组肺癌细胞系中证实了Notch3过表达，并表明Notch3与19p易位高度相关。因此，我们已经确定了肺癌中癌基因激活的一种新的复发机制，以及一种以前不知道与人类癌症有关的推定癌基因。在David Carbone博士的指导下，Dang博士将完成鉴定的t（15;19）易位的分子表征，确定Notch3受体和配体在肺癌和正常组织中的表达谱，并开展Notch3在肺癌中的转化性质及其对下游信号通路的影响的研究。范德比尔特英格拉姆癌症中心的研究环境非常出色，将为Dang博士提供与经验丰富的分子生物学家和遗传学家互动的机会。K08奖项给予的支持将使Dang博士能够在现有知识的基础上，在竞争激烈的环境中促进她向独立研究者的过渡。

This is an application for a K08 award for Thao Dang, M.D. designed to support five-years of laboratory training to further develop her skills in molecular genetics and to explore a novel mechanism of carcinogenesis. Malignant transformation is the result of an accumulation of genetic abnormalities. Specific chromosomal translocations are a major mechanism for oncogene activation in hematopoietic malignancies, but have not been described in the much more common epithelial tumors. We have established a cell line, HCC2429, from an aggressive, metastatic lung cancer that has a normal karyotype except for a single translocation between chromosomes 15q and 19p. Using positional cloning we demonstrated that the breakpoint on chromosome 19 lies approximately 40 kb upstream from the start site of Notch3, a member of the Notch proto- oncogene family. This translocation is associated with massive overexpression of Notch3, supporting the hypothesis that the t(15;19) translocation results in the deregulation of this putative cellular proto-oncogene. Furthermore, we have also demonstrated Notch3 over-expression in a panel of lung cancer cell lines and shown that it is highly correlated with translocations involving 19p. We have therefore identified a novel recurring mechanism for oncogene activation in lung cancer as well as a putative oncogene not previously known to be involved in human cancer. Under the mentorship of Dr. David Carbone, Dr. Dang will complete the molecular characterization of the identified t(15;19) translocation, determine the spectrum of the Notch3 receptor and ligand expression in lung cancer and normal tissues, and perform studies to characterize the transforming nature of Notch3 and its effects on downstream signaling pathways in lung cancer. The research environment at the Vanderbilt Ingram Cancer Center is of exceptional caliber and will provide Dr. Dang with the opportunity to interact with experienced molecular biologists as well as geneticists. The support given by this K08 award will allow Dr. Dang to build on her existing knowledge and promote her transition to an independent investigator in a highly competitive environment.