MAMMARY CARCINOGENESIS--THE ROLE OF PLEIOTROPHIN

乳腺癌发生：增殖素的作用。乳腺癌生长 转移需要肿瘤细胞和肿瘤细胞之间的生长因子信号。 周围正常的宿主组织。我们建议，秘密的 多肽生长因子多营养素(PTN)在多种疾病中发挥重要作用 乳腺癌的发生及其在乳腺生长和转移中的作用 癌症。这一假设是基于PTN的生物效应。 在选定的肿瘤模型中，PTN mRNA的高水平表达在60% 乳腺癌患者肿瘤标本及其上调的研究进展 在致癌物诱导的啮齿动物乳腺癌期间。此外，PTN是 在未成熟的小鼠乳腺中高度表达，这些乳腺对 致癌物质，并在经历了 怀孕，并可防止致癌。最后，活动 PTN在体外对内皮细胞的作用提示PTN可以作为一种 肿瘤进展过程中的血管生成因子。为了支持这一角色 PTN作为一种血管生成因子，结构性表达减少 PTN靶向核酶在人肿瘤细胞内源性Rib mRNA中的表达 减少肿瘤的生长和转移，即使在体外生长的 肿瘤细胞没有受到影响。 基于这些初步研究，我们希望阐明PTN的作用 在乳腺癌进展和乳腺癌发生中的作用 最终目标是开发更好的预后标记物以及新的 治疗策略。 在目标1下，我们将研究乳腺癌患者血清甲状旁腺素水平 患者可以预测他们疾病的长期结果，或者 对治疗的反应。我们将使用10年以上患者的样本 从我们的血清库核心设施进行后续的这项分析。在……下面 目的2我们将研究激素调节对PTN的影响程度 乳腺成熟和癌变过程中的表达 在啮齿动物模型中。我们将研究类固醇激素和 视黄酸受体配体对PTN表达的影响及对乳腺的影响 在动物和器官培养中的生物学或致癌作用。在目标3下 我们将研究肋骨在多大程度上保持高水平的表达 会影响乳腺成熟、荷尔蒙反应和 乳腺不同阶段对致癌物的易感性 成熟。为了实现这一点，我们将在小鼠中表达ptn作为转基因。 在四环素调控的启动子下。我们将研究一种 转基因动物(和器官外植体)对激素的挑战 刺激物以及致癌物。在目标4下，我们将研究什么 内源性PTN表达的降低程度将影响乳腺 生理学和病理学。我们将使用核酶靶向肋骨来 实现这一目标。我们将产生表达PTN靶向的小鼠 四环素调控启动子控制下的核酶和 研究妊娠期间的自发性腺体成熟以及 激素和致癌物对内源性PTN攻击的影响 被核酶转基因抑制。在目标5下，我们将开发基因 将载体转移到体内核酶靶向表达的肋骨。我们会 使用腺病毒和疱疹病毒为基础的载体进行基因转移。

Mammary Carcinogenesis: The Role of Pleiotrophin. Breast cancer growth and metastasis requires growth factor signals between the tumor cells and the normal surrounding host tissue. We propose that the secreted polypeptide growth factor pleiotrophin (PTN) plays a major role in mammary carcinogenesis as well as in the growth and metastasis of breast cancer. This hypothesis is based on the biological effects of PTN expression in selected tumors models, the high levels of PTN mRNA in 60% of tumor samples from breast cancer patients and on its upregulation during carcinogen-induced rodent mammary cancer. Furthermore, PTN is highly expressed in immature mouse mammary glands that are sensitive to carcinogens and is downregulated permanently in mice that have undergone pregnancy and are protected against carcinogenesis. Finally, the activity of PTN on endothelial cells in vitro suggests that PTN can serve as an angiogenesis factor during tumor progression. In support of this role of PTN as an angiogenesis factor, reduction of constitutively expressed endogenous rib mRNA in human tumor cell lines by PTN-targeted ribozymes reduced tumor growth and metastasis even when in vitro growth of the tumor cells remained unaffected. Based on these preliminary studies, we wish to elucidate the role of PTN in breast cancer progression and in mammary carcinogenesis with the ultimate goal to develop better prognostic markers as well as novel therapeutic strategies. Under aim 1 we will study whether serum levels of PTN in breast cancer patients can predict long term outcome of their disease an-or the response to therapy. We will use samples from patients with over 10 years of follow-up from our serum bank core facility for this analysis. Under aim 2 we will study to what extent hormonal regulation affects PTN expression in mammary gland maturation and during mammary carcinogenesis in rodent models. We will study the influence of steroid hormones and retinoid acid receptor ligands on PTN expression and on mammary gland biology or carcinogenesis in animals and in organ culture. Under aim 3 we will study to what extent sustained high levels of expression of rib will affect mammary gland maturation, hormonal responsiveness and susceptibility to carcinogens at different stages of mammary gland maturation. To achieve this, we will express PTN as a transgene in mice under a tetracycline-regulated promoter. We will study the effects of a challenge of the transgenic animals (and of organ explants) with hormonal stimuli as well as with carcinogens. Under aim 4 we will study to what extent reduction of endogenous PTN expression will affect mammary gland physiology and pathology. We will use ribozyme-targeting of rib to achieve this goal. We will generate mice expressing PTN-targeted ribozymes under the control of a tetracycline-regulated promoter and study spontaneous gland maturation during pregnancy as well as the effects of hormonal and carcinogen challenges with the endogenous PTN suppressed by the ribozyme transgene. Under aim 5 we will develop gene transfer vectors to target rib expression with ribozymes in vivo. We will use adenovirus- and herpes virus-based vectors for gene transfer.