Xing Chengguo, LaPorte Jacob R, Barbay Joseph K, Myers Andrew G
Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, MA 02128, USA.
Proc Natl Acad Sci U S A. 2004 Apr 20;101(16):5862-6. doi: 10.1073/pnas.0307476101. Epub 2004 Apr 12.
Saframycin A (SafA) is a member of a class of natural products with potent antiproliferative effects in leukemia- and tumor-derived cells. This activity is frequently conjectured to derive from the ability of saframycins to covalently modify duplex DNA. We used a DNA-linked affinity purification technique to identify GAPDH as a protein target of DNA-small molecule adducts of several members of the saframycin class. Nuclear translocation of GAPDH occurs upon treatment of cancer cells with saframycins, and depletion of cellular GAPDH levels by small interfering RNA transfection confers drug resistance. Roeder and coworkers have recently suggested that GAPDH is a key transcriptional coactivator necessary for entry into S phase. Our data suggest that GAPDH is also capable of forming a ternary complex with saframycin-related compounds and DNA that induces a toxic response in cells. These studies implicate a previously unknown molecular mechanism of antiproliferative activity and, given that one member of the saframycin class has shown efficacy in cancer treatment, suggest that GAPDH may be a potential target for chemotherapeutic intervention.
沙弗霉素A（SafA）是一类天然产物中的一员，这类天然产物对白血病细胞和肿瘤衍生细胞具有强大的抗增殖作用。人们常常推测这种活性源于沙弗霉素共价修饰双链DNA的能力。我们使用了一种DNA连接亲和纯化技术来鉴定甘油醛-3-磷酸脱氢酶（GAPDH）是沙弗霉素类几种成员的DNA-小分子加合物的蛋白质靶点。用沙弗霉素处理癌细胞后，GAPDH会发生核转位，通过小干扰RNA转染降低细胞内GAPDH水平可赋予耐药性。罗德及其同事最近提出，GAPDH是进入S期所必需的关键转录共激活因子。我们的数据表明，GAPDH还能够与沙弗霉素相关化合物和DNA形成三元复合物，从而在细胞中诱导毒性反应。这些研究揭示了一种此前未知的抗增殖活性分子机制，而且鉴于沙弗霉素类中的一个成员已在癌症治疗中显示出疗效，这表明GAPDH可能是化疗干预的一个潜在靶点。
