The role of the mucin Muc4 signaling in breast cancer formation and progression

描述（由申请人提供）：膜粘蛋白Muc4在多种癌中过表达。一些证据表明，Muc4可能在健康上皮向早期增生性表型的初始转化以及后来向高度侵袭性和转移状态的转变中发挥作用。例如，据报道，与患者匹配的正常组织样本相比，20%的局部乳腺肿瘤中Muc4过表达和错定位。再加上Muc4表达足以转化小鼠成纤维细胞的观察结果，这些观察结果提出了Muc4在乳腺癌启动事件中发挥积极作用的可能性。也有报道称，与患者匹配的原发性肿瘤相比，Muc4蛋白在大多数乳腺癌淋巴结转移中高度上调，这表明Muc4蛋白在后期与转移进展相关的事件中发挥作用。本文概述的研究试图严格评估Muc4在乳腺癌发病和进展中的作用，使用MCF10A进展系列，一个模拟正常、增生性和恶性乳腺组织的等基因细胞系系列。推动上述研究的假设是Muc4过表达参与特定的信号通路，促进细胞逐渐向更恶性的状态转变。这项研究将分为两个具体目标。特异性Aim 1将表征Muc4过表达对MCF10A进展系列细胞系体外生长特性的影响。在这些实验中，将使用四环素诱导的Muc4稳定地转导MCF10A进展系列细胞，并测量Muc4对细胞转化、增殖、运动性和侵袭性的影响，以及Muc4依赖性的生长和存活信号通路的增强。这些研究还将使用Matrigel基质检测Muc4过表达对三维细胞培养中细胞生长的影响。特异性Aim 2将确定Muc4过表达是否在体内正常乳腺环境中诱导从低恶性到高恶性状态的转变。在Aim 1中建立的细胞系将被原位导入裸鼠乳腺脂肪垫，在没有Muc4诱导和有Muc4诱导的情况下，测量肿瘤潜伏期、大小和转移率。收集组织的组织学分析将用于评估muc4诱导的癌症分期转变。上述研究的成功完成可能意味着Muc4作为未来乳腺癌治疗干预的新靶点。PI的培训机会包括小鼠生物学，病理学和外科课程，每周一次与UCD乳腺生物学和病理学小组的会议，一系列广泛的研讨会，肿瘤委员会和癌症生物学和治疗专题讨论会，以及与病理学家和统计学家的密切合作。这项研究的结果将在第三年的全国癌症生物学会议上发表。

DESCRIPTION (provided by applicant): The membrane mucin Muc4 is overexpressed in a variety of carcinomas. Some evidence has accumulated suggesting that Muc4 may have roles in both the initial transformation of healthy epithelia to early hyperplastic phenotypes and in latr transitions to highly invasive and metastatic states. For example, it has been reported that Muc4 is overexpressed and mislocalized in 20% of local breast tumors compared to patient-matched normal tissue samples. Coupled with observations that Muc4 expression is sufficient to transform mouse fibroblasts, these observations raise the possibility that Muc4 plays an active role in initiating events in breast cancer. It has also been reported that Muc4 protein is highly upregulated in the majority of breast cancer lymph node metastases compared to patient-matched primary tumors, pointing to a role in later events related to progression to metastasis. The studies outlined here seek to rigorously assess the roles of Muc4 in breast cancer onset and progression using the MCF10A progression series, an isogenic series of cell lines modeling normal, hyperplastic, and malignant breast tissue. The hypothesis driving the proposed studies is that Muc4 overexpression engages specific signaling pathways to promote cellular transitions to progressively more malignant states. The study will be broken down into two specific aims. Specific Aim 1 will characterize the impact of Muc4 overexpression on the in vitro growth properties of the MCF10A progression series cell lines. In these experiments, the MCF10A progression series cells will be stably transduced with tetracycline-inducible Muc4, and the impact of Muc4 on cellular transformation, proliferation, motility, and invasiveness will be measured, along with Muc4-dependent potentiation of growth and survival signaling pathways. These studies will also examine the impact of Muc4 overexpression on the growth of cells in three dimensional cell cultures using the Matrigel matrix. Specific Aim 2 will determine whether Muc4 overexpression induces transitions from less malignant to more malignant states in the normal mammary environment in vivo. The cell lines created in Aim 1 will be orthotopically introduced into nude mouse mammary fat pads, and tumor latency, size, and rate of metastasis will be measured without and with Muc4 induction. Histological analysis of collected tissues will be employed to assess Muc4-induced transitions in cancer stage. The successful completion of the proposed studies could implicate Muc4 as a novel target for future therapeutic intervention in breast cancer. Training opportunities for the PI include classes in mouse biology, pathology and surgery, weekly meetings with the UCD mammary gland biology and pathology group, an extensive series of seminars, tumor boards and symposia in cancer biology and therapeutics, and close collaboration with pathologists and statisticians. Results emerging from the study will be presented at a national conference in cancer biology in Year 3.