TNF-ALPHA AND ITS RECEPTORS IN PEDIATRIC ACUTE LEUKEMIA

描述：尽管在儿童治疗方面取得了重大进展， 急性淋巴细胞白血病（ALL），约35%的儿童 这种疾病会复发或诱导治疗失败。 申请人已经 观察到肿瘤坏死因子-α（TNF）的内源性产生， 儿童ALL细胞可能与难治性疾病有关。 白血病生长 大多数受试患者的细胞生长受到TNF的抑制， 呈剂量依赖性，并伴有细胞凋亡。 相反，细胞 从一个子集的患者产生TNF和耐药的抑制 外源性TNF的作用。 白血病细胞系来源于产生TNF， TNF-抗性（TNF+）细胞和来自TNF-非产生、TNF-敏感（TNF-） 细胞保留了原代细胞对外源性TNF的反应性。 TNF+和TNF-细胞系均表达p60和p80 TNF受体（TNF受体）， 表明这些品系之间TNF应答的表型差异 不是由于TNF受体表达的改变。 初步实验 表明TNF+和TNF-细胞在调节 基因毒性处理后某些凋亡/存活相关基因。 此外，临床数据表明，TNF+表型与 难治性疾病和预后不良： TNF+ ALL患者在诊断后1年完全缓解率为20 而TNF-ALL为89%。 他假设内源性TNF 作为TNF+ ALL细胞的存活因子， 凋亡 为了检验这一假设，他提出了以下具体目标： 1)为了进一步研究TNF+和TNF- ALL细胞系对 外源性TNF、阿霉素和IR的表达差异， 凋亡与DNA损伤后的存活基因; 2）为了确定 阻断内源性TNF产生（使用TNF反义表达 构建体）影响TNF+ ALL细胞系对外源性TNF的应答， 3）观察阿霉素诱导的内源性 TNF（使用TNF表达载体）对TNF-ALL细胞系的应答 4）检测儿童ALL的原代白血病细胞 患者的TNF和TNF受体的表达，并将这些数据 对遗传毒性药物有临床反应和体外反应; 5） 测定重组TNF-假单胞菌内毒素的细胞毒性 （TNF-PE）在体外的TNFR+ ALL细胞中以及在SCID模型中， 移植性白血病

DESCRIPTION: Despite substantial advances in the treatment of childhood acute lymphoblastic leukemia (ALL), approximately 35 percent of children with this disease will relapse or fail induction therapy. The applicant has observed that endogenous production of tumor necrosis factor-alpha (TNF) by pediatric ALL cells may be linked to refractory disease. Growth of leukemic cells by the majority of patients tested was inhibited by TNF in a dose-dependent manner and was accompanied by apoptosis. In contrast, cells from a subset of patients produced TNF and were resistant to the inhibitory effects of exogenous TNF. Leukemic cell lines derived from TNF-producing, TNF-resistant (TNF+) cells and from TNF-nonproducing, TNF sensitive (TNF-) cells retained the responsiveness of the primary cells to exogenous TNF. Both TNF+ and TNF- lines expressed p60 and p80 TNF receptors (TNFrs), suggesting that phenotypic differences in TNF response between these lines are not due to altered expression of TNFrs. Preliminary experiments indicate marked differences between TNF+ and TNF-cells in the regulation of certain apoptosis/survival associated genes after genotoxic treatments. Moreover, clinical data suggest that the TNF+ phenotype is associated with refractory disease and poor prognosis: The percentage of patients remaining in complete remission at one year post-diagnosis was 20 percent for TNF+ ALL cells vs 89 percent for TNF- ALL. He hypothesizes that endogenous TNF acts as a survival factor for TNF+ ALL cells, protecting these cells from apoptosis. To test the hypothesis, he proposes the following specific aims: 1) To further investigate the response of TNF+ and TNF- ALL cell lines to exogenous TNF, adriamycin, and IR by examining differences in expression of apoptosis vs. survival genes following DNA damage; 2) To determine if blockade of endogenous TNF production (using a TNF-antisense expression construct) affects the response of TNF+ ALL cell lines to exogenous TNF, adriamycin, and IR; 3) To investigate the effects of induction of endogenous TNF (using a TNF expression vector) on the response of TNF- ALL cell lines to these agents; 4) To examine primary leukemic cells fro pediatric ALL patients for expression of TNF and TNF receptors, and to correlate this data with clinical response and in vitro response to genotoxic agents; 5) To determine the cytotoxicity of a recombinant TNF-Pseudomonas endotoxin (TNF-PE) for TNFR+ ALL cells in vitro as well as in the SCID model for engrafted leukemia.