Inhibition of breast cancer progression by vitamin D analogs and triterpenoids

描述(由申请人提供)： 乳腺癌的发生发展涉及多种信号通路和转录因子的改变。我们正在研究两种类型的核受体配体，一种是新型的维生素D受体配体(一种非高钙的双子维生素D类似物)，另一种是PPARg配体(一种独特的三萜类化合物)，用于抑制乳腺癌的进展。我们的初步数据显示，双子座维生素D类似物和三萜类化合物调节Smad信号通路，并协同抑制培养的MCF10乳腺癌细胞的增殖。我们推测，双子座维生素D类似物和三萜类化合物调节核受体信号和转化生长因子-b/Smad系统，这些作用有助于它们在体内抑制乳腺癌的进展。为了验证这一假说，我们计划追求以下特定目标：(1)研究具有代表性的双子座维生素D类似物和三萜类化合物单独和联合使用在培养的MCF10乳腺癌细胞系(具有不同进展程度)中的分子机制；(2)测定双子座维生素D类似物和三萜类化合物对MCF10乳腺癌动物模型的体内疗效，并阐明相关的作用机制；(3)验证双子座维生素D类似物和三萜类化合物对MMTV-neo雌激素受体(ER)阴性乳腺癌动物模型的体内疗效。为了研究这些药物对乳腺癌进展的体内疗效和分子机制，我们将使用代表不同进展阶段的MCF10细胞株注射到免疫缺陷小鼠体内。我们将通过检测(A)核受体和辅助激活子的相互作用，(B)转录激活和靶基因的调节，以及(C)双子维生素D类似物和三萜类化合物对Smad信号和翻译后修饰的调节来研究这些药物在MCF10乳腺细胞系中协同作用的分子机制。MCF10乳腺癌异种移植模型和MMTV-neu乳腺癌转基因小鼠模型将用于确定双子维生素D类似物和三萜类化合物单独和联合治疗ER阴性乳腺癌的体内疗效。我们的建议侧重于确定新的核受体配体，作为抑制ER阴性乳腺癌的有前途的药物。这一点很重要，因为目前用于预防/治疗ER阴性乳腺癌的药物数量有限。我们对一种新的非高钙双子维生素D类似物和一种抑制乳腺癌进展的新的三萜类化合物的研究将为预防ER阴性乳腺癌提供重要的临床前数据。 本建议旨在研究两种核受体配体，一种新型的非高钙双子维生素D类似物和一种新型的三萜类化合物，作为抑制乳腺癌形成和进展的药物。我们将研究这两种药物对核受体信号的调节，重点是这两种药物对转化生长因子-b/Smad信号通路的调节，并在雌激素受体阴性乳腺癌进展的动物模型中确定它们的体内疗效。我们期望通过双子维生素D类似物和一种独特的三萜类化合物的组合找到协同抑制乳腺癌进展的方法。这项研究将为雌激素受体阴性乳腺癌高危患者的临床癌症预防试验提供重要的先导。

DESCRIPTION (provided by applicant): Progression of mammary carcinogenesis involves numerous alterations in signaling pathways and transcription factors. We are studying two types of nuclear receptor ligands, a novel vitamin D receptor ligand (a non- hypercalcemic Gemini vitamin D analog) and a PPARg ligand (a unique triterpenoid), for inhibition of breast cancer progression. Our preliminary data show that Gemini vitamin D analogs and triterpenoids regulate the Smad signaling pathway and synergize to inhibit the proliferation of cultured MCF10 breast cancer cells. We hypothesize that Gemini vitamin D analogs and triterpenoids regulate nuclear receptor signaling and the TGF- b/Smad system, and these effects contribute to their inhibition of the progression of breast cancer in vivo. To test this hypothesis, we plan to pursue the following Specific Aims: (1) investigate the molecular mechanism of a representative Gemini vitamin D analog and a triterpenoid, alone and in combination, in cultured MCF10 breast cancer cell lines (with different degrees of progression), (2) determine the in vivo efficacy of a Gemini vitamin D analog and a triterpenoid in an animal model of MCF10 breast cancer and elucidate the mechanisms of action involved, and (3) verify the in vivo efficacy of the Gemini vitamin D analog and a triterpenoid in an animal model of MMTV-neu estrogen receptor (ER)-negative breast cancer. To study the in vivo efficacy and molecular mechanisms of these agents against breast cancer progression, we will use the MCF10 cell lines that represent different stages of progression when injected into immunodeficient mice. We will investigate the molecular mechanism of synergy of these agents by examining (a) interactions of nuclear receptors and coactivators, (b) regulation of transcriptional activation and target genes, and (c) regulation of Smad signaling and post-translational modification by a Gemini vitamin D analog and a triterpenoid in the MCF10 breast cell lines. The MCF10 breast cancer xenograft model and the MMTV-neu breast cancer transgenic mouse model will be used for determining in vivo efficacy of a Gemini vitamin D analog and a triterpenoid, alone and in combination, in ER-negative breast cancer. Our proposal focuses on the identification of novel nuclear receptor ligands as promising agents for the inhibition of ER-negative breast cancer. This is important because there are currently only a limited number of agents for the prevention/treatment of ER-negative breast cancer. Our research with a novel non-hypercalcemic Gemini vitamin D analog and a novel triterpenoid that inhibits breast cancer progression will provide important preclinical data for the prevention of ER-negative breast cancer.Project Summary/Narrative This proposal is to study two nuclear receptor ligands, a novel non-hypercalcemic Gemini vitamin D analog and a novel triterpenoid, as agents for inhibition of breast cancer formation and progression. We will investigate the regulation of nuclear receptor signaling with a focus on the TGF-b/Smad signaling pathway by these two agents, and we will determine their in vivo efficacy in animal models of estrogen receptor negative breast cancer progression. We anticipate finding synergistic inhibition of breast cancer progression by the combination of a Gemini vitamin D analog and a unique triterpenoid. This research will be an important precursor for a clinical cancer prevention trial in patients with a high risk of estrogen receptor negative breast cancer.