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

1) BCL6。BCL-6/LAZ3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3q27相关易位的断点。为了研究细胞反应和与BCL-6信号通路相关的靶基因，我们建立了Ba/F3前b细胞，该细胞携带在乳糖操纵子控制下可诱导的人BCL-6转基因。利用CDNA阵列杂交技术，我们发现诱导的BCL-6蛋白可以下调Ba/F3细胞中cyclin A2、趋化因子受体CXCR4和胰岛素样生长因子结合蛋白4 （IGFBP-4）基因的表达。Northern blot分析证实，这些基因的表达确实被诱导的BCL-6蛋白下调，但表达方式有所不同。诱导的BCL-6蛋白也能抑制Ba/F3细胞的增殖。这些发现强烈提示，在B淋巴细胞分化过程中，三个关键基因cyclin A2、CXCR4和IGFBP-4可能在BCL-6信号通路的下游发挥重要作用。2) API2-MALT1。t(11;18)（q21;q21）是粘膜相关淋巴组织（MALT）型淋巴瘤的特征性染色体易位，这种易位导致API2（凋亡抑制剂2，也称为c-IAP2） - MALT1（粘膜相关淋巴瘤易位基因1）的嵌合转录。为了鉴定与API2-MALT1嵌合蛋白结合的蛋白，我们采用了共免疫沉淀和SDS PAGE分析，然后采用液相色谱-电喷雾电离串联质谱法。结果，Smac、Htra2和TRAF2被鉴定为api2 - malt1结合蛋白。免疫沉淀分析表明，异位表达的API2-MALT1蛋白确实与这些内源性蛋白结合。此外，API2-MALT1蛋白显著抑制smac促进的紫外线照射HeLa细胞凋亡。这些数据强烈提示，API2-MALT1可以通过抑制smac介导的凋亡途径，至少在一定程度上阻断细胞凋亡。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