Overexpression of phospholipase D1 in human breast cancer tissues

Phospholipase D (PLD) catalyzes the hydrolysis of phosphatidylcholine (PC) to produce phosphatidic acid (PA) and choline. PLD is a major enzyme implic ated in important cellular processes. such as cell proliferation. We design ed this study to investigate the expression of PLD in human breast carcinom as and non-malignant tissues using RT-PCR, Western blot analysis, immunohis tochemistry and an Arf-dependent PLD activity assay. We examined about 550 bp of PCR product and 120 kDa of PLD protein, Our results showed that PLD p rotein and mRNA levels were overexpressed in 14 of 17 breast cancer tissues , We also observed increased expression by immunohistochemistry and Arf-dep endent PLD activity in microsomes of human breast tumors, which correlated well with PLD expression. PLD expression was elevated in human breast tumor s compared with normal breast tissues. These results implicate a possible r ole of PLD in human breast tumorigenesis and suggest that PLD may be useful as a marker for malignant disease in the breast. (C) 2000 Elsevier Science Ireland Ltd, All rights reserved.