Kuhajda F P, Jenner K, Wood F D, Hennigar R A, Jacobs L B, Dick J D, Pasternack G R
Department of Pathology, Johns Hopkins Medical Institutions, Baltimore, MD 21205.
Proc Natl Acad Sci U S A. 1994 Jul 5;91(14):6379-83. doi: 10.1073/pnas.91.14.6379.
OA-519 is a prognostic molecule found in tumor cells from breast cancer patients with markedly worsened prognosis. We purified OA-519 from human breast carcinoma cells, obtained its peptide sequence, and unambiguously identified it as fatty acid synthase through sequence homology and enzymology. Tumor fatty acid synthase is an approximately 270-kDa polypeptide which specifically abolished immunostaining of human breast cancers by anti-OA-519 antibodies. Tumor fatty acid synthase oxidized NADPH in a malonyl-CoA-dependent fashion and synthesized fatty acids composed of 80% palmitate, 10% myristate, and 10% stearate from acetyl-CoA, malonyl-CoA, and NADPH with a specific activity of 624 nmol of NADPH oxidized per min per mg. Tumor cell lines with elevated fatty acid synthase showed commensurate increases in incorporation of [U-14C]acetate into acylglycerols demonstrating that fatty acid synthase increases occur in the context of overall increases in endogenous fatty acid synthesis. Cerulenin inhibited acylglycerol synthesis in tumor cells and fibroblast controls in a dose-dependent fashion and also caused a growth inhibition which generally paralleled the level of endogenous fatty acid synthesis. Supraphysiologic levels of palmitate, 14 microM in dimethyl sulfoxide, significantly reversed the growth inhibition caused by cerulenin at concentrations of up to 5 micrograms/ml, indicating that cerulenin-mediated growth inhibition was due to fatty acid synthase inhibition.
OA - 519是一种在预后明显恶化的乳腺癌患者肿瘤细胞中发现的预后分子。我们从人乳腺癌细胞中纯化了OA - 519，获得了其肽序列，并通过序列同源性和酶学明确鉴定其为脂肪酸合酶。肿瘤脂肪酸合酶是一种约270 kDa的多肽，抗OA - 519抗体可特异性消除其对人乳腺癌的免疫染色。肿瘤脂肪酸合酶以丙二酰辅酶A依赖的方式氧化NADPH，并从乙酰辅酶A、丙二酰辅酶A和NADPH合成由80%棕榈酸、10%肉豆蔻酸和10%硬脂酸组成的脂肪酸，比活性为每分钟每毫克氧化624 nmol NADPH。脂肪酸合酶水平升高的肿瘤细胞系显示，[U - 14C]乙酸掺入酰基甘油的量相应增加，这表明脂肪酸合酶的增加是在内源脂肪酸合成总体增加的背景下发生的。浅蓝菌素以剂量依赖的方式抑制肿瘤细胞和成纤维细胞对照中的酰基甘油合成，还导致生长抑制，这通常与内源性脂肪酸合成水平平行。在二甲基亚砜中14 μM的超生理水平棕榈酸显著逆转了浅蓝菌素在浓度高达5 μg/ml时引起的生长抑制，表明浅蓝菌素介导的生长抑制是由于脂肪酸合酶抑制。
