ERBB REGULATION OF BREAST DEVELOPMENT AND TUMORIGENESI

描述：(申请人摘要)ERBB受体和配体已被 与乳房发育和肿瘤发生有关。在申请人的办公室工作 实验室通过显示一个基因的过度表达强化了这一观点 ErbB1/EGFR激动剂，转化生长因子-α，通常在人类乳腺癌中升高， 有效地诱导小鼠乳腺肿瘤。腺体发育和 内卷化也令人不安，这不仅表明这可能会设置 后续肿瘤发生的阶段，但这些过程可能是 也可以通过ERBB信号正常调节。事实上，他后来的研究 结果表明，四种ERBB受体及其多重配体均为 在处女期、妊娠期、哺乳期和退化期的小鼠乳腺中表达 腺体，虽然在不同的时间模式一致，不同的作用。 他们还提供了ERBB之间功能相互作用的重要证据 活体内的受体。最后，他开发的基因敲除小鼠缺乏几个 EGFR配体(双调节蛋白(AR)、转化生长因子-α、EGF)单独或组合 已确定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，而AR共同作用 有了EGF和转化生长因子-α，正常的小叶肺泡发育和 差异化。继续这种对老鼠模型的卓有成效的强调， 申请人现在希望解决他以前的工作中提出的几个问题。 首先，他将调查在导管中对AR的要求 形态发生反映了独特的激动剂特性，由不同的 ERBB配体的体外生物活性。这将通过派生 携带AR编码序列发生敲入突变的小鼠 被转化生长因子-α所取代。第二，他将调查这一事件的性质 雷达信号。他将首先检验这样一个假设，即旁分泌激活 间质EGFR是导管形态发生所必需的；这将通过以下方式实现 衍生出只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 和差减cdna克隆，然后他将致力于鉴定其基因产物 AR依赖的表达或激活对导管的形态发生至关重要。 第三，使用新颖的基因敲除小鼠模型，他将确定三个 其他EGF家族激动剂在发育中或 分化和激活EGFR和ERBB4也有作用。第四, 他将研究ERBB4的生理和病理作用 信号，并专门测试ERBB4促进细胞 分化而不是增殖。这将通过以下方式实现 产生过表达野生型ERBB4或 携带EGFR胞外区的受体嵌合体偶联 ERBB4的信号域。ERBB4的抑制能力 转化生长因子-α诱导的乳腺肿瘤形成将在双转基因试验中进行。 同时携带受体嵌合体和转化生长因子-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.