Role of CCN6 (WISP3) in the progression and metastasis of breast cancer

化生性乳腺癌（mBrCA）是三阴性乳腺癌（TNBC）的一个子集， 在非洲和非洲裔美国人（AA）女性中发生率较高，有组织学证据表明， 上皮-间质转化（EMT），与其他TNBC相比预后差。mBrCAs 由梭形细胞组成的是最常见和最致命的亚型。人类TP 53突变 在mBrCA和非化生性TNBC中的频率相似（60-80%的病例）。目前，定义 mBrCA的分子改变还远未被理解， mBrCA为54%，而TNBC为73%。我们的实验室发现，CCN 6蛋白减少了68%， 与其他乳腺癌类型的33%相比，人类mBrCA的比例为33%（p<0.02）。这是我们的一项重大突破， 在前一个周期中，实验室已经产生了乳腺上皮细胞特异性Ccn 6敲除 小鼠模型，其证明了mBrCA中Ccn 6的肿瘤抑制功能。所有乳腺肿瘤， MMTV-Cre; Ccn 6 fl/fl小鼠在形态上和转录水平上类似于人纺锤体mBrCA， 在78%的肿瘤中，它们的β-连环蛋白核定位增加， 典型Wnt靶基因HMGA 2和IMP 2（IGF 2BP 2）的表达。自首次提交以来，我们 发现细胞外CCN 6拮抗Wnt配体对体内β-连环蛋白激活的作用 和体外，但机制、合作事件和功能后果需要进一步研究 调查我们的中心假设是，CCN 6表达的缺失是驱动纺锤体所必需的。 mBrCA，至少部分通过增强Wnt/β-连环蛋白介导的促侵袭和促增殖的活化， 转移靶点，如HMGA 2和IMP 2，以及CCN 6、β-连环蛋白、HMGA 2和 IMP 2蛋白可作为临床组织样品中mBrCA的特异性生物标志物，具有诊断和 治疗效用我们提出了三个独立和互补的具体目标：目标1。探讨 可诱导的乳腺上皮细胞特异性Ccn 6敲除的结果作为一个独特的驱动程序， 纺锤体mBrCA表型，并研究与p53的合作。AIM 2.为了阐明 CCN 6在体内和体外抑制纺锤体mBrCA进展的机制。AIM 3.到 评估CCN 6、β-连环蛋白、HMGA 2和IMP 2在乳腺组织样本中的翻译影响， 非洲人AA和白人我们已经开发了一种独特的小鼠模型，并表征了 人乳腺癌组织（n> 4，000，包括来自加纳的200例，以及所有mBrCA的275例 种族）与临床信息和>15年的随访。我们已经生成了关键的初步数据， 这提供了一个强有力的科学前提。试剂和专业知识已在PI和Co中就位。 调查员的实验室。我们的创新研究有望为新的诊断方法提供见解。 目前尚不存在这种侵袭性TNBC亚型的标志物和治疗靶点。

Metaplastic breast carcinomas (mBrCAs) are a subset of triple negative breast cancer (TNBC) that occurs with higher frequency in African and African-American (AA) women, have histological evidence of epithelial-to-mesenchymal transition (EMT), and poor prognosis compared with other TNBC. mBrCAs consisting of spindle cells are the most frequent and the most lethal subtype. In humans TP53 is mutated with similar frequency in mBrCAs and in non-metaplastic TNBC (60-80% of cases). At present, the defining molecular alterations of mBrCAs are far from understood, and the 5-year overall survival for patients with mBrCA is 54% compared to 73% for TNBC. Our lab has discovered that CCN6 protein is reduced in 68% of human mBrCAs compared to 33% of other breast cancer types (p<0.02). A major breakthrough in our lab during the previous cycle has been the generation of a mammary epithelial cell-specific Ccn6 knockout mouse model that demonstrates a tumor suppressor function for Ccn6 in mBrCAs. All mammary tumors in MMTV-Cre;Ccn6fl/fl mice resemble human spindle mBrCAs morphologically and at the transcriptional level, and they share increased nuclear localization of beta-catenin in 78% of tumors, and increased expression of the canonical Wnt target genes HMGA2 and IMP2 (IGF2BP2). Since the initial submission, we have discovered that extracellular CCN6 antagonizes the effect of Wnt ligands on beta-catenin activation in vivo and in vitro, but the mechanisms, cooperating events, and functional consequences need further investigation. Our CENTRAL HYPOTHESIS is that loss of CCN6 expression is required to drive spindle mBrCAs, at least in part by enhancing Wnt/beta-catenin mediated activation of pro-invasive and pro- metastatic targets, such as HMGA2 and IMP2, and that detection of CCN6, beta-catenin, HMGA2, and IMP2 proteins may serve as specific biomarkers of mBrCA in clinical tissue samples, with diagnostic and treatment utility. We propose three independent and complementary specific aims: AIM 1. To investigate the consequences of inducible mammary epithelial cell-specific Ccn6 knockout as a driver of the unique spindle mBrCA phenotype, and to investigate the cooperation with p53. AIM 2. To elucidate the molecular mechanism(s) by which CCN6 suppresses progression of spindle mBrCAs in vivo and in vitro. AIM 3. To evaluate the translational impact of CCN6, beta-catenin, HMGA2, and IMP2 in breast tissue samples of African, AA, and Whites. We have developed a unique mouse model and have characterized cohorts of human breast cancer tissues (n>4,000, including 200 from Ghanaian, and 275 cases of mBrCAs of all races) with clinical information and >15 years of follow-up. We have generated critical preliminary data, which provide a strong scientific premise. The reagents and expertise are in place in the PI and co- Investigator's laboratories. Our innovative studies are expected to provide insights into new diagnostic markers and therapeutic targets for this aggressive subtype of TNBC, which are currently nonexistent.