EBV EXPRESSION IN NASOPHARYNGEAL CARCINOMA

本研究的目的是确定EB病毒在鼻咽癌病因学中的作用。鼻咽癌是一种上皮性恶性肿瘤，在非洲北部的中国南部和爱斯基摩人中高发。在鼻咽癌中表达的病毒基因包括潜伏性膜蛋白LMP1和LMP2，以及通过BamHI A片段转录的一组mRNAs，它们可能编码四种先前未知的蛋白质。LMP1与肿瘤坏死因子受体(TNFR)相关因子(TRAF)相互作用，激活NfkappaB转录因子和JNK激酶。我们已经证明，LMP1通过TRAF相互作用结构域诱导表皮生长因子受体(EGFR)的表达，并且通过突变TRAF相互作用产生了两个对EGFR诱导的温度敏感的突变体。我们已经确定LMP1的两个激活结构域诱导不同形式的NfkappaB转录因子。我们还表明，LMP1通过诱导A20抑制P53介导的细胞凋亡。在这项资助中，我们将进一步分析LMP1介导的转化的生化基础，以及LMP2和BamHI A蛋白在上皮细胞中的生物学和生化特性。我们的具体目标是：1)鉴定LMP1在上皮细胞中激活不同形式的NfkappaB的信号转导途径，并确定受这些信号转导途径影响的细胞基因；2)确定LMP1和A20的表达对P53介导的细胞凋亡的影响；3)分析LMP2在上皮细胞中的抑制作用，并确定LMP2表达影响的生化途径；4)鉴定BamHI A开放阅读框在细胞和鼻咽癌中编码的蛋白质；5)确定RK-BARF0与Notch相互作用对Notch信号转导的影响；6)确定BamHI A蛋白的表达对病毒和细胞表达的影响。

The goal of this research is to determine the role of EBV in the etiology of nasopharyngeal carcinoma (NPC), an epithelial malignancy that develops with high incidence in Southern China, Northern Africa, and among Eskimoes. The viral genes that are expressed in NPC include the latent membrane proteins, LMP1 and 2, and a family of mRNAs, transcribed through the BamHI A fragment, that potentially encode four previously unidentified proteins. LMP1 interacts with the tumor necrosis factor receptor (TNFR) associated factors (TRAFS) through which it activates the NfkappaB transcription factor and JNK kinase. We have shown that LMP1 induces the expression of epidermal growth factor receptor (EGFR) through the TRAF interacting domain and by mutating the TRAF interacting have produced two mutants that are temperature sensitive with regard to EGFR induction. We have determined that the two activation domains of LMP1 induce distinct forms of the NfkappaB transcription factor. We have also shown that LMP1 inhibits p53-mediated apoptosis through induction of A20. In this grant, we will further analyze the biochemical basis of LMP1-mediated transformation and the biologic and biochemical properties of LMP2 and the BamHI A proteins in epithelial cells. Our specific aims are to 1) Characterize the signal transduction pathways activated by LMP1 in epithelial cells that activate distinct forms of NfkappaB and identify the cellular genes that are affected by these pathways, 2) Determine the effect of LMP1 and A20 expression on p53-mediated apoptosis, 3) Analyze LMP2 suppression in epithelial cells and identify the biochemical pathways affected by LMP2 expression, 4) Identify the proteins encoded by the BamHI A open reading frames in cell lines and in NPC tumors, 5) Determine the effect of the interaction of RK- BARF0 with Notch on Notch signaling, 6) Determine the effects of expression of the BamHI A proteins on viral and cellular expression.