Chow S N, Lin J K, Li S S, Chien C H
Department of Obstetrics and Gynecology, College of Medicine, National Taiwan University, Taipei.
Gynecol Oncol. 1997 Jan;64(1):114-20. doi: 10.1006/gyno.1996.4531.
Normal ovarian and ovarian cancer tissues from 35 patients were tested for LDH-A-ras protein complex formation, as well as for the expression of ras and LDH-A genes. By immunodetection of the immunoprecipitates, LDH-A-ras protein complexes are present in the homogenates of human ovarian tissues (benign and malignant). Two bands of 21 and 36 kDa were demonstrated in affinity-purified LDH active fractions by Western blot analysis, and these two proteins were proved to be ras p21 and LDH-A by immunodetection. By Northern blot analysis, elevated levels of c-Ki-ras and LDH-A mRNA transcripts were noted in 49% (17/35) and 40% (14/35) of ovarian cancers, respectively. Concurrent high expression of both genes was demonstrated in 11 cases (31%). Tyrosylphosphorylation of LDH-A was demonstrated in normal and malignant ovarian tissues, and the extent of phosphorylation was correlated with the stage of ovarian cancer. The concurrent elevated expression of ras and LDH-A in the same ovarian tissue may imply that the increased synthesis of LDH-A is due to increased or amplified signaling of the ras-cascade pathway. The possible biochemical role of the tyrosylphosphorylated LDH-A complexed with ras p21 in cell transformation and progression of human ovarian cancer is worthy of further investigation.
对35例患者的正常卵巢组织和卵巢癌组织进行了乳酸脱氢酶A（LDH-A）-ras蛋白复合物形成以及ras和LDH-A基因表达的检测。通过对免疫沉淀物的免疫检测，发现人卵巢组织（良性和恶性）匀浆中存在LDH-A-ras蛋白复合物。通过蛋白质印迹分析在亲和纯化的LDH活性组分中显示出两条分别为21 kDa和36 kDa的条带，经免疫检测证明这两种蛋白分别为ras p21和LDH-A。通过Northern印迹分析，分别在49%（17/35）的卵巢癌中发现c-Ki-ras mRNA转录水平升高，在40%（14/35）的卵巢癌中发现LDH-A mRNA转录水平升高。11例（31%）患者同时出现这两种基因的高表达。在正常和恶性卵巢组织中均检测到LDH-A的酪氨酸磷酸化，且磷酸化程度与卵巢癌分期相关。ras和LDH-A在同一卵巢组织中同时升高表达可能意味着LDH-A合成增加是由于ras级联信号通路的增强或放大。与ras p21复合的酪氨酸磷酸化LDH-A复合物在人卵巢癌细胞转化和进展中可能的生化作用值得进一步研究。
