TOXINS TARGETED TO THE CELL MEMBRANE--DISRUPTION OF SIGNAL TRANSDUCTION

该项目寻求开发能够干扰细胞的靶向制剂。 信号转导，作为蛋白质抑制的补充或替代 综合。来自LBC的研究此前表明，霍乱毒素(CT)可以 抑制某些癌细胞株的生长。因此，努力 在过去的一年里，他们专注于第一，创造新的手段 将CT-A链输送到恶性肿瘤细胞表面，第二， 在临床相关情况下确定新的靶点 可能是被导演的。我们已经构建了人工基因，在其中CT-A 链核苷酸序列与白喉片段在框架内融合 毒素(DT)序列对膜转位很重要，该片段 反过来也在帧中与序列一起编码，在单独的构造中， IL-2和EGF。这种构建体可以靶向带有受体的肿瘤。 对于这些增长因素。我们现在正试图表达这些 构建的方式将允许CT保留酶活性。 我们还在一系列白血病样本中定义了来自 皮肤T细胞淋巴瘤(CTCL)认为IL-7是重要的共刺激因子 生长因子与IL-2、IL-7受体和IL-7配体m-RNA相互作用 在一小部分患者来源的样本中表达，而IL-7 刺激导致IL-7和IL-2受体上调。我们 已经完成了一项临床试验，证明了 白喉毒素-IL-2融合蛋白DAB486-IL-2在CTCL中的表达。 这些研究共同指出了IL-7和IL-2的重要性 CTCL中的受体系统是治疗药物的重要靶点 可以干扰细胞内的信号传递。我们也在继续进行 抗DC19和抗CD22抗体作为类比检测手段的研究 B细胞内干扰信号及抗DC19和抗CD22的定向 B细胞淋巴瘤患者的免疫毒素。

This project seeks to develop targeted agents which disrupt cellular signal transduction, in addition to or instead of inhibition of protein synthesis. Work from LBC had previously shown that cholera toxin (CT) can inhibit the growth of certain carcinoma cell lines. Therefore efforts during the past year have focused on first, creating novel means of delivering CT-A chain to the surface of malignant cells, and second, defining novel targets in clinically relevant circumstances at which CT might be directed. We have constructed artificial genes in which the CT-A chain nucleotide sequence is fused in frame with a segment of diphtheria toxin (DT) sequence important for membrane translocation, and this segment is in turn also in frame with sequences encoding, in separate constructs, IL-2 and EGF. Such constructs could target neoplasms bearing receptors for these growth factors. We are now attempting to express these constructs in a way that will allow retention of enzymatic activity by CT. We have also defined in a series of leukemic specimens from patients with cutaneous T-cell lymphoma (CTCL) that IL-7 is an important co-stimulatory growth factor with IL-2, that IL-7 receptor and IL-7 ligand m-RNA are expressed in a fraction of patient-derived specimens, and that IL-7 stimulation leads to up regulation of both IL-7 and IL-2 receptors. We have completed a clinical trial which demonstrated clinical activity of DAB486 IL-2, a chimeric diphtheria toxin-IL2 fusion protein in CTCL. Collectively these studies point to the importance of the IL-7 and IL-2 receptor systems in CTCL as important targets for therapeutic agents which can disrupt intracellular signalling. We are also continuing ongoing studies of anti DC19 and anti CD22 antibodies as means of analogously disrupting signals in B-cells, and of anti-DC19 and anti-CD22 directed immunotoxins in patients with B-cell lymphoma.