MOLECULAR DETERMINANTS OF SENSITIVITY TO IFN IN CML

α-干扰素在15%的CML患者中诱导细胞遗传学缓解。 这些缓解与降低的演变概率有关 到疾病的急变期 这项建议旨在 确定可用于改变 髓系细胞对α-干扰素的反应性和细胞免疫应答 敏感性或抵抗力的决定因素。 的调节 干扰素基因，它们的细胞作用，以及对 干扰素及其对干扰素诱导基因的作用是介导的 通过转录调节蛋白。 其中包括IRF-1和 IRF-2、正、负调节因子分别占 其决定了细胞对细胞激活的敏感性。 干扰素信号转导途径 IRF-1已被证明与 干扰素基因的转录增强子和干扰素- 诱导基因 此外，ISGF 3 α和ISGF 3-γ直接 参与干扰素诱导基因的转录激活 α-干扰素 为了开发出改变比例的方法 IRF-1和IRF-2在细胞内，因此使细胞对 激活干扰素信号转导通路，我们着手 克隆和分析5'转录调控区， IRF-1和IRF-2基因的启动子。 我们已经完成了克隆， IRF-1基因及其5 ′启动子区（Cha，DNA 和Cell Biology 11：605-611，1992）。 我们在功能上描述了 IRF-1基因的转录启动子（西姆斯，出版中，分子生物学杂志， 和Cellular Biology，1992）。 我们已经克隆了IRF-2基因， 目前表征其启动子（Cha，1992）。 另外我们 研究已经确定了一种细胞因子， 在ISGF 3之间形成的复合物的电泳迁移率 和IRF-1核调节蛋白和转录增强子 干扰素诱导基因的表达（Seong等，JCI 86：1664-1770，1990）。 这是一种蛋白质二硫键异构酶（PDI）蛋白（约翰逊等人，JBC 267：14412-14417，1992），其在CML细胞中升高，并且其在CML细胞中升高。 与对干扰素敏感性的改变有关（霍华德et 等人，Blood 76：1117-1130，1990）。 最后，我们已经表明，持续时间 并且可以改变对α-干扰素的细胞应答的大小 通过γ-干扰素预处理（Gao等，Submitted，JBC，1992）。 我们 建议通过以下方式扩展这些发现：（1）制定方法， 改变细胞内IRF-1和IRF-2的比例以改变它们的 对干扰素途径的敏感性;（2）功能表征 氧化还原蛋白，这是与改变状态的α- 干扰素敏感性;和（3）表征γ-干扰素如何 引起细胞反应的幅度和持续时间的变化 到α-干扰素 这些研究将帮助我们了解 α-干扰素反应的机制，以确定分子 α-干扰素敏感性和抗性的决定因素， 为新的治疗策略奠定基础， 对α-干扰素反应的敏感性，以及规避耐药性。 这可以将α-干扰素的益处扩展到更多数量的受试者。 慢粒患者。

Alpha-interferon induces cytogenetic remissions in 15% of CML patients. These remissions are associated with a reduced probability of evolution to the blastic phase of the disease. this proposal is designed to identify molecular mechanisms which may be used to alter the responsiveness of myeloid cells to alpha-interferon and the cellular determinants of sensitivity or resistance. The regulation of the interferon genes, their cellular actions, and the sensitivity to interferon and its effect on interferon-inducible genes are mediated through transcriptional regulatory proteins. Among these are IRF-1 and IRF-2, positive and negative regulatory factors respectively, the ratio of which determines the sensitivity of the cell to activation of the interferon signal transduction pathway. IRF-1 has been shown to bind to the transcriptional enhancers of the interferon genes and the interferon- inducible genes. In addition, ISGF3alpha and ISGF3-gamma are directly involved in the transcriptional activation of interferon-inducible genes by alpha-interferon. In order to develop methods of altering the ratio of IRF-1 and IRF-2 within cells, therefore sensitizing the cells to activation of the interferon signal transduction pathway, we set out to clone and analyze the 5' transcriptional regulatory regions of the promoters of IRF-1 and IRF-2 genes. We have completed the cloning and total sequencing of the IRF-1 gene and its 5' promoter region (Cha, DNA and Cell Biology 11:605-611, 1992). We have functionally characterized the transcriptional promoter of the IRF-1 gene (Sims, In press, Molecular and Cellular Biology, 1992). We have cloned the IRF-2 gene and are currently characterizing its promoter (Cha, 1992). In addition, our studies have identified a cellular factor which alters the electrophoretic mobility of the complexes which form between the ISGF3 and IRF-1 nuclear regulatory proteins and the transcriptional enhancers of interferon-inducible genes (Seong et al, JCI 86:1664-1770, 1990). this is a protein disulfide isomerase (PDI) protein (Johnson et al, JBC 267:14412-14417, 1992) which is elevated in CML cells, and which is associated with altered states of sensitivity to interferon (Howard et al, Blood 76:1117-1130, 1990). finally, we have shown that the duration and magnitude of the cellular response to alpha-interferon can be altered by gamma-interferon pretreatment (Gao et al, Submitted, JBC, 1992). We are proposing to extend these findings by: (1) developing ways of altering the ratio of IRF-1 and IRF-2 within ells to alter their sensitivity to the interferon pathway; (2) functionally characterizing the redox protein which is associated with altered states of alpha- interferon sensitivity; and (3) characterizing how gamma-interferon induces a change in the magnitude and duration of the cellular response to alpha-interferon. These studies will help us to understand the mechanism of the alpha-interferon response, to identify the molecular determinants of the sensitivity and resistance to alpha-interferon, to lay the foundation for new therapeutic strategies to enhance cellular sensitivity to alpha-interferon response, and to circumvent resistance. This may extend the benefits of alpha-interferon to greater numbers of CML patients.