RETINOIC ACID RECEPTOR BETA AND BREAST CANCER

视黄酸受体 β 与乳腺癌

• 批准号: 6377356
• 负责人: KAREN L SWISSHELM
• 金额: $ 26.26万
• 依托单位: UNIVERSITY OF WASHINGTON
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-08-04 至 2004-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6377356
• 关键词: biopsy; breast neoplasms; cell line; clinical research; female; gene induction /repression; human subject; immunocytochemistry; mammary epithelium; neoplastic cell; posttranslational modifications; protein isoforms; protein localization; receptor expression; retinoid binding proteins; transcription factor; tumor suppressor proteins

Retinoic acid receptor beta (RARbeta), and in particular RAR-beta2, RARbeta2 is a candidate tumor suppressor for human mammary gland tissue. RARbeta expression at the mRNA and protein level, in contrast to RARalpha and RARgamma, declines or is lost during breast tumor progression. Transcriptional and protein analysis suggests that the mechanism for this down-regulation or loss of expression is multi-factorial and includes transcriptional, post-transcriptional, and potential post-translational modifications. Breast cancer cells may exploit one or more of these regulatory controls of the RARbeta function in order to inhibit normal cellular functions. We wish to test the hypothesis that the RARbeta2 isoform is a tumor suppressor protein and that the recently identified human RARbeta4 isoform has the property of a dominant-negative transcription factor. We intend to characterize the critical regulatory mechanisms of RARbeta gene expression and function in normal human mammary epithelial cells (HMECs) and malignant breast carcinoma cells. We will characterize RARbeta transcripts and protein products as well as and the intracellular location of the proteins. We will introduce the truncated RARbeta4 transcripts, detected in breast cancer nuclei, into normal cells to study the biological consequences of nuclear localization. In order to test the hypothesis that differential levels, as well as aberrant subcellular localization, of RARbeta isoforms is a characteristic of primary breast cancers, we will utilize immunocytochemical (ICC) detection of RARbeta proteins against a panel of well-characterized breast cancer specimens. In order to determine transcriptional components necessary for repression of RARbeta and subsequent gene action in breast cancer cells, we will identify and characterize components of the transcriptional machinery influencing RARbeta2 transcription in breast tumor cells. These studies will provide the cytological and molecular basis for enhancing potential novel retinoid-directed therapies for human breast carcinoma as well as the basis for RARbeta as a diagnostic or prognostic tool.

维甲酸受体β(RARbeta)，特别是RAR-β2，RARbeta2是人类乳腺组织的候选肿瘤抑制因子。与RARpha和RARGamma不同，RARbeta在mRNA和蛋白质水平上的表达在乳腺癌进展过程中下降或丢失。转录和蛋白质分析表明，这种表达下调或丧失的机制是多因素的，包括转录后、转录后和潜在的翻译后修饰。乳腺癌细胞可能会利用RARbeta功能的一个或多个调控来抑制正常的细胞功能。我们希望验证一种假设，即RARbeta2亚型是一种肿瘤抑制蛋白，而最近发现的人类RARbeta4亚型具有显性负转录因子的特性。我们打算描述RARbeta基因在正常人乳腺上皮细胞(HMECs)和恶性乳腺癌细胞中表达和功能的关键调控机制。我们将鉴定RARbeta转录本和蛋白质产物，以及蛋白质在细胞内的位置。我们将把在乳腺癌细胞核中检测到的截短的RARbeta4转录本引入正常细胞，以研究核定位的生物学后果。为了验证RARbeta亚型的不同水平以及异常的亚细胞定位是原发性乳腺癌的特征这一假设，我们将利用免疫细胞化学(ICC)对一组特征良好的乳腺癌标本进行RARbeta蛋白的检测。为了确定在乳腺癌细胞中抑制RARbeta和随后的基因作用所必需的转录成分，我们将鉴定和表征影响乳腺癌细胞中RARbeta2转录的转录机制的成分。这些研究将为加强潜在的维甲酸导向治疗人类乳腺癌提供细胞学和分子基础，并为RARbeta作为诊断或预后工具提供基础。