Li Tianhong, Sotgia Federica, Vuolo Magalis A, Li Maomi, Yang Wan Cai, Pestell Richard G, Sparano Joseph A, Lisanti Michael P
Department of Cancer Biology, Kimmel Cancer Center, Bluemle Life Sciences Building, Room 933, 233 S. 10th Street, Philadelphia, PA 19107, USA.
Am J Pathol. 2006 Jun;168(6):1998-2013. doi: 10.2353/ajpath.2006.051089.
A Japanese study reported that up to 16% of breast cancer samples harbor a sporadic mutation within the human Cav-1 gene, namely P132L. To date, however, no studies have examined the United States' population. Here, we developed a novel allele-specific real-time PCR assay to detect the Cav-1 P132L mutation in mammary tumor cells isolated by laser capture microdissection from formalin-fixed paraffin-embedded breast cancer samples. We report that the Cav-1 P132L mutation is present in approximately 19% of estrogen receptor alpha (ERalpha)-positive breast cancers but not in ERalpha-negative breast cancers. This is the first demonstration that the P132L mutation is exclusively associated with ERalpha-positive mammary tumors. We also identified six novel Cav-1 mutations associated with ERalpha-positive breast cancers (W128Stop, Y118H, S136R, I141T, Y148H, and Y148S). Thus, the overall incidence of Cav-1 mutations in ERalpha-positive breast cancers approaches 35% (greater than one-third). To mechanistically dissect the functional relationship between Cav-1 gene inactivation and ERalpha expression, we isolated primary mammary epithelial cells from wild-type and Cav-1-/- mice and cultured them in a three-dimensional system, allowing them to form mammary acinar-like structures. Under conditions of growth factor deprivation, Cav-1-deficient mammary acini displayed increased ERalpha levels and enhanced sensitivity toward estrogen-stimulated growth, with specific up-regulation of cyclin D1. Finally, we discuss the possibility that sporadic Cav-1 mutations may act as an initiating event in human breast cancer pathogenesis.
一项日本研究报告称，高达16%的乳腺癌样本在人类Cav-1基因内存在散发性突变，即P132L。然而，迄今为止，尚无研究对美国人群进行过检测。在此，我们开发了一种新型等位基因特异性实时PCR检测方法，以检测通过激光捕获显微切割从福尔马林固定石蜡包埋的乳腺癌样本中分离出的乳腺肿瘤细胞中的Cav-1 P132L突变。我们报告称，Cav-1 P132L突变存在于约19%的雌激素受体α（ERα）阳性乳腺癌中，但不存在于ERα阴性乳腺癌中。这是首次证明P132L突变仅与ERα阳性乳腺肿瘤相关。我们还鉴定出了六个与ERα阳性乳腺癌相关的新型Cav-1突变（W128Stop、Y118H、S136R、I141T、Y148H和Y148S）。因此，ERα阳性乳腺癌中Cav-1突变的总体发生率接近35%（超过三分之一）。为了从机制上剖析Cav-1基因失活与ERα表达之间的功能关系，我们从野生型和Cav-1基因敲除小鼠中分离出原代乳腺上皮细胞，并在三维系统中培养它们，使其形成乳腺腺泡样结构。在生长因子缺乏的条件下，Cav-1缺陷的乳腺腺泡显示出ERα水平升高，对雌激素刺激的生长敏感性增强，细胞周期蛋白D1特异性上调。最后，我们讨论了散发性Cav-1突变可能作为人类乳腺癌发病起始事件的可能性。
