ISSN:
1432-1335
Keywords:
Key words Phospholipase D
;
Breast tumor
;
Phosphatidylcholine
;
Phosphatidylethanol
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Abstract Phospholipase D is believed to play an important role in cell proliferation and tumorigenesis. One of its major functions is to cause a sustained activation of protein kinase C through the primary production of phosphatidic acid from phosphatidylcholine by the enzyme, followed by dephosphorylation forming diacylglycerol. Protein kinase C is known to be activated or translocated in some tumors including breast tumors. In order to examine phospholipase D activity in breast tumors, surgical specimens of human breast tumors were obtained by mastectomy or wide excision, and their phospholipase D activities were assayed by determining the formation of phosphatidylethanol from phosphatidylcholine and ethanol. Phospholipase D activity was predominantly localized in the microsomal fraction of the tumor tissue and markedly stimulated by oleic acid. We observed a significant increase in phospholipase D activity in 17 out of 19 spontaneous human breast tumors as compared to adjacent histologically normal breast tissue. The mean specific activity in the tumors was 52.9 ± 41.8 (SD) pmol min−1 mg protein−1 whereas the value for the normal breast tissue was 34.0 ± 36.2 (SD) pmol min−1 mg protein−1 (P〈0.01; paired Wilcoxon's rank-sum test). The mean tumor/normal activity ratio was 2.37. Among prognostic factors, the nuclear grade, evaluated according to Schnitt et al., was found to be correlated with the activity ratio. Our results suggest a role for phospholipase D in human breast tumors. An elevation in phospholipase D activity is useful as a potential marker for malignant disease in the breast.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01208639
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