Molecular analysis of B-cell malignant lymphoma-related oncogenes and its clinical application for diagnosis and treatment.

1)BCL6。BCL-6/LAZ 3基因编码锌指转录抑制因子，位于非霍奇金淋巴瘤（NHL）中最常发生的3q 27相关易位的断点处。为了检查与BCL-6信号传导途径相关的细胞反应和靶基因，我们建立了携带人BCL-6转基因的Ba/F3 pro-B细胞，该转基因在乳糖操纵子的控制下是可诱导的。利用cDNA阵列杂交技术，我们发现诱导的BCL-6蛋白能下调Ba/F3细胞中细胞周期蛋白A2、趋化因子受体CXCR 4和胰岛素样生长因子结合蛋白4（IGFBP-4）等基因的表达。北方印迹分析证实，这些基因的表达确实被诱导的BCL-6蛋白下调，但方式略有不同。诱导表达的BCL-6蛋白对Ba/F3细胞的增殖也有抑制作用。这些发现有力地表明，三个关键基因，即cyclin A2，CXCR 4和IGFBP-4，可能发挥作用。 ...更多信息 le在B -淋巴分化过程中BCL-6信号通路的下游。2）API 2-MALT 1。t（11; 18）（q21; q21）是粘膜相关淋巴组织（MALT）型淋巴瘤中的特征性染色体易位，并且该易位导致API 2（凋亡抑制剂2，也称为c-IAP 2）-MALT 1（粘膜相关淋巴瘤易位基因1）的嵌合转录物。为了鉴定结合API 2-MALT 1嵌合蛋白的蛋白，我们采用免疫共沉淀和SDS PAGE分析，然后通过液相色谱-电喷雾串联质谱。结果，Smac、Htra 2和TRAF 2被鉴定为API 2-MALT 1结合蛋白。免疫沉淀分析表明，异位表达的API 2-MALT 1蛋白确实结合这些内源性蛋白。此外，API 2-MALT 1蛋白显着抑制Smac促进的细胞凋亡在紫外线照射的HeLa细胞。这些数据有力地表明，API 2-MALT 1可以阻断凋亡，至少部分，通过抑制Smac介导的凋亡途径。少

1) BCL6. The BCL-6/LAZ3 gene encodes a zinc-finger transcriptional repressor and is located at the breakpoint of the 3q27-associated translocations that occur most frequently in non-Hodgkin's lymphomas (NHLs To examine cell responses and target genes related to the BCL-6 signaling pathway, we established Ba/F3 pro-B cells carrying a human BCL-6 transgene that is inducible under control of the lactose operon. Using a CDNA array hybridization technique, we found that the induced BCL-6 protein can downregulate the expressions of the genes, cyclin A2, chemokine receptor CXCR4, and insulin-like growth factor binding protein-4 (IGFBP-4) in the Ba/F3 cells. Northern blot analysis established that the expressions of these genes were indeed downregulated by the induced BCL-6 protein but in a somewhat different manner. The induced BCL-6 protein also inhibited cell proliferation of Ba/F3 cells. These findings strongly suggest that three key genes, namely cyclin A2, CXCR4 and IGFBP-4 may play a ro … More le in the downstream of the BCL-6 signaling pathway during B - lymphoid differentiation.2) API2-MALT1. t(11;18)(q21;q21) is a characteristic chromosomal translocation in mucosa-associated lymphoid tissue (MALT) type lymphoma, and this translocation results in chimeric transcript of API2 (Apoptosis Inhibitor 2, also known as c-IAP2) - MALT1 (Mucosa-Associated Lymphoma Translocation gene 1). To identify proteins that bind API2-MALT1 chimeric protein, we employed coimmunoprecipitation and SDS PAGE analysis, followed by liquid chromatography-electrospray ionization tandem mass spectrometry. As a result, Smac, Htra2, and TRAF2 were identified as API2-MALT1-binding proteins. Immunoprecipitation analysis demonstrated that ectopically expressed API2-MALT1 protein indeed binds to these endogeneous proteins. Furthermore, API2-MALT1 protein significantly inhibited Smac-promoted apoptosis in UV irradiated HeLa cells. These data strongly suggest that API2-MALT1 can block apoptosis, at least in part, by inhibiting Smac-mediated apoptotic pathway. Less