Dawson Louise A, Maitland Norman J, Berry Paul, Turner Anthony J, Usmani Badar A
Proteolysis Research Group, School of Biochemistry & Microbiology, University of Leeds, Leeds LS2 9JT, United Kingdom.
Exp Biol Med (Maywood). 2006 Jun;231(6):1106-10.
Endothelin (ET)-1 can influence cancer invasion and metastasis by exerting an autocrine (epithelial) or paracrine (stromal) influence on growth. ET-1 is generated from big ET-1 by endothelin-converting enzyme (ECE)-1, which has four recognized isoforms, ECE-1a, ECE-1b, ECE-1c, and ECE-1d, differing only in their amino-terminal regions. This study investigated the expression and localization of the ECE-1 isoforms in prostate cancer (PC). The epithelial cell lines used were androgen-sensitive LNCaP, androgen-independent PC-3 and Du145, and nonmalignant transformed PNT1-a, PNT2-C2, and P4E6 prostate cells. Primary cells derived from malignant and benign tissue from radical prostatectomies were also exploited. Previously, we reported increased ECE-1 expression in androgen-independent PC cell lines, as compared with androgen-sensitive cells. Our present data show that transcripts for all ECE-1 isoforms were present in all epithelial cell lines analyzed. However, only the ECE-1c protein was detectable in PC-3, Du145, PNT2-C2, and PNT1-a cells. ECE-1c localized to both the cell surface and intracellular compartments in individual cell lines. In primary stromal cells, all individual ECE-1 isoforms were expressed at the mRNA level, with the exception of ECE-1a. ECE-1b and ECE-1c protein levels were higher in malignant stromal cells, as compared with benign cells. In stroma, ECE-1c protein was localized to the cell surface, with filamentous immunoreactivity throughout the cell, whereas ECE-1b immunoreactivity was punctate throughout the cytoplasm. The upregulation of the ECE-1c isoform in PC cell lines is being investigated further.
内皮素（ET）-1可通过对生长发挥自分泌（上皮）或旁分泌（基质）作用来影响癌症的侵袭和转移。内皮素转换酶（ECE）-1可将大内皮素-1转化为ET-1，ECE-1有四种公认的亚型，即ECE-1a、ECE-1b、ECE-1c和ECE-1d，它们仅在氨基末端区域有所不同。本研究调查了ECE-1亚型在前列腺癌（PC）中的表达和定位。所用的上皮细胞系包括雄激素敏感的LNCaP、雄激素非依赖的PC-3和Du145，以及非恶性转化的PNT1-a、PNT2-C2和P4E6前列腺细胞。还利用了来自根治性前列腺切除术的恶性和良性组织的原代细胞。此前，我们报道与雄激素敏感细胞相比，雄激素非依赖的PC细胞系中ECE-1表达增加。我们目前的数据表明，在所有分析的上皮细胞系中均存在所有ECE-1亚型的转录本。然而，仅在PC-3、Du145、PNT2-C2和PNT1-a细胞中可检测到ECE-1c蛋白。ECE-1c定位于单个细胞系的细胞表面和细胞内区室。在原代基质细胞中，除ECE-1a外，所有单个ECE-1亚型均在mRNA水平表达。与良性细胞相比，恶性基质细胞中ECE-1b和ECE-1c蛋白水平更高。在基质中，ECE-1c蛋白定位于细胞表面，细胞内有丝状免疫反应性，而ECE-1b免疫反应性在整个细胞质中呈点状。PC细胞系中ECE-1c亚型的上调正在进一步研究中。
