ERBB REGULATION OF BREAST DEVELOPMENT AND TUMORIGENESIS

描述：（申请人的摘要）ERBB受体和配体已经被公开， 与乳腺发育和肿瘤发生有关。在申请人的工作 实验室已经证实了这一观点， ERBB 1/EGFR激动剂，TGF-α，其通常在人乳腺癌中升高， 在小鼠中有效地诱导乳腺肿瘤。腺体发育和 对合也感到不安，这不仅表明这可能会使 而且这些过程可能是 也通过ERBB信号正常调节。事实上，他后来的研究 结果表明，四种ERBB受体及其多种配体都是 在处女、妊娠、哺乳和退化小鼠乳腺中表达 腺，虽然在不同的时间模式与不同的角色一致。 它们还为ERBB与细胞内的细胞因子之间的功能相互作用提供了重要证据。 体内受体。最后，他开发的基因敲除小鼠缺乏几个 EGFR配体（双调蛋白（AR）、TGF-α、EGF）单独或组合 ERBB信号在乳腺发育和功能中的作用。 因此，AR是青春期导管形态发生所必需的， EGF和TGF-α是正常小叶肺泡发育所必需的， 分化继续这种富有成效的重视小鼠模型， 申请人现在希望解决由其先前的工作提出的几个问题。 首先，他将调查是否需要在导管中进行AR 形态发生反映了独特的激动剂特性，这是由以下差异所暗示的： ERBB配体的体外生物活性。这将通过导出 携带AR编码序列已被基因敲入突变的小鼠 被TGF-α取代。第二，他将调查的性质， AR信号。他将开始通过测试的假设，旁分泌激活 间质EGFR是导管形态发生所必需的;这将通过以下方式实现： 衍生仅表达膜锚定的生物活性AR前体的小鼠。 使用蛋白质和RNA分析的组合，包括微阵列筛选 和消减cDNA克隆，然后他将致力于鉴定基因产物， AR依赖性表达或激活对导管形态发生至关重要。 第三，使用新颖的基因敲除小鼠模型，他将确定是否有三个 在发育中表达的其他EGF家族激动剂或 分化和激活EGFR和ERBB 4两者，也具有作用。第四、 他将研究ERBB 4的生理和病理作用， 信号，并特别测试ERBB 4促进细胞增殖的假设。 分化而不是增殖。这将通过 产生过表达野生型ERBB 4或野生型ERBB 5的转基因小鼠。 受体嵌合体携带EGFR的细胞外结构域， ERBB 4的信号结构域。ERBB 4抑制 TGF-α诱导的乳腺肿瘤发生将在双转基因小鼠中进行测试。 携带受体嵌合体和TGF-α转基因的小鼠。

DESCRIPTION: (Applicant's Abstract) ERBB receptors and ligands have been implicated in breast development and tumorigenesis. Work in the applicant's laboratory has reinforced this view by showing that overexpression of an ERBB1/EGFR agonist, TGF-alpha, which is often elevated in human breast cancer, efficiently induces mammary tumors in mice. Glandular development and involution were also perturbed, suggesting not only that this might set the stage for subsequent tumorigenesis but also that these processes might be regulated normally via ERBB signaling as well. Indeed, his subsequent studies showed that the four ERBB receptors and their multiple ligands are all expressed in the virgin, pregnant, lactating, and involuting mouse mammary gland, albeit in different temporal patterns consistent with distinct roles. They also provided important evidence of functional interactions between ERBB receptors in vivo. Finally, his development of knockout mice lacking several EGFR ligands (amphiregulin (AR), TGF-alpha, EGF) individually or in combination established roles for ERBB signaling in mammary gland development and function. Thus, AR was required for pubescent ductal morphogenesis, while AR together with EGF and TGF-alpha was required for normal lobuloalveolar development and differentiation. Continuing this fruitful emphasis on mouse models, the applicant now wishes to address several issues raised by his previous work. First, he will investigate whether the requirement for AR in ductal morphogenesis reflects unique agonist properties as suggested by differences in the bioactivity of ERBB ligands in vitro. This will be accomplished by deriving mice harboring a knock-in mutation in which AR coding sequences have been replaced by those of TGF-alpha. Second, he will investigate the nature of the AR signal. He will begin by testing the hypothesis that paracrine activation of stromal EGFR is required for ductal morphogenesis; this will be accomplished by deriving mice that express only membrane-anchored, bioactive AR precursor. Using a combination of protein and RNA analyses, including microarray screening and subtractive cDNA cloning, he will then work to identify gene products whose AR-dependent expression or activation is critical for ductal morphogenesis. Third, using novel, knockout mouse models, he will determine whether three additional EGF family agonists that are expressed in the developing or differentiating and activate both EGFR and ERBB4, have roles as well. Fourth, he will investigate the physiological and pathological roles of ERBB4 signaling, and specifically test the hypothesis that ERBB4 promotes cellular differentiation rather than proliferation. This will be accomplished by generating transgenic mice that overexpress either wild type ERBB4 or a receptor chimera bearing the extracellular cellular domain of EGFR coupled to the signaling domain of ERBB4. The ability of ERBB4 to suppress TGF-alpha-induced mammary tumorigenesis will then be tested in bitransgenic mice harboring both receptor chimera and TGF-alpha transgenes.