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

化生性乳腺癌(MBrca)是发生在三重阴性乳腺癌(TNBC)的子集 在非洲和非裔美国人(AA)女性中频率较高，有组织学证据表明 上皮向间充质转化(EMT)，与其他TNBC相比预后较差。MBrCAs 由梭形细胞组成的是最常见和最致命的亚型。在人类中，TP53发生突变 在mBrca和非化生的TNBC中的表达频率相近(60-80%)。目前，定义 MBrCA的分子改变还远未被了解，而患有MBrCA的患者的5年总生存期 MBrCA为54%，而TNBC为73%。我们的实验室发现CCN6蛋白减少了68% 相比之下，其他类型乳腺癌的这一比例为33%(p&lt；0.02)。我们的一项重大突破 Lab在前一个周期中已经产生了乳腺上皮细胞特异性的Ccn6基因敲除 MBrca中Ccn6具有肿瘤抑制功能的小鼠模型。年所有乳腺肿瘤 Ccn6fl/fl小鼠在形态和转录水平上与人纺锤体mBrCA相似， 他们分享了78%的肿瘤中β-连环素的核定位增加和表达增加。 典型的Wnt靶基因HMGA2和IMP2(IGF2BP2)。自最初提交以来，我们已经 发现细胞外CCN6拮抗Wnt配体对β-连环蛋白激活的影响 在体外，但机制、协同事件和功能后果还需要进一步研究 调查。我们的中心假设是CCN6表达的缺失是驱动纺锤体所必需的 MBrCA，至少部分是通过增强Wnt/β-catenin介导的前侵袭性和前侵袭性的激活。 转移靶点，如HMGA2和IMP2，以及CCN6、β-连环蛋白、HMGA2和 IMP2蛋白可作为临床组织标本中mBrCA的特异性生物标志物，具有诊断和鉴别诊断作用 治疗工具。我们提出了三个独立和互补的具体目标：目标1.调查 可诱导乳腺上皮细胞特异性Ccn6基因敲除作为唯一驱动因素的后果 纺锤体mBrCA表型，并探讨其与P53的协同作用。目的2.阐明分子 体内和体外CCN6抑制纺锤体mBrCA进展的机制(S)。目标3.至 评估CCN6、β-连环蛋白、HMGA2和IMP2在小鼠乳腺组织样本中的翻译影响 非洲人、AA人和白人。我们已经开发了一种独特的老鼠模型，并描述了一系列 人乳腺癌组织(4,000例，其中200例来自加纳，275例mBrCA) 比赛)与临床信息和&gt；15年的随访。我们已经生成了关键的初步数据， 这为我们提供了强有力的科学前提。试剂和专业知识在PI和合作伙伴中到位- 调查员的实验室。我们的创新研究有望为新的诊断提供见解 这种侵袭性的TNBC亚型的标志物和治疗靶点目前还不存在。

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.