EFFECT OF SESAMIN ON GROWTH AND ARACHIDONIC-ACID CONTENT OF NEOPLASTIC AND NONNEOPLASTIC PROSTATE EPITHELIAL-CELL CULTURES

Sesamin (a lignan present in sesame oil) is reported to specifically i nhibit Delta 5 desaturation and the formation of arachidonic acid (20: 4n-6) from dihomogamma-linolenic acid (20:3n-6) in cell free extracts. In this study the effects of sesamin have been evaluated on cell cult ures derived from canine prostatic tissues of epithelial origin from n eoplastic and non-neoplastic tissues. Sesamin reduced cell proliferati on in a dose dependent manner in both cell lines with TD50 values of 9 1 +/- 16 mu M (non-neoplastic) and 132 +/- 12 mu M (neoplastic). In th e non-neoplastic cells, supplemented with gamma-linolenic acid (18:3n- 6) in the culture media, sesamin had little effect on the content of C 16 and C18 fatty acids but markedly reduced the content of 20:4n-6 and caused an accumulation of 20:3n-6, This observation is consistent wit h sesamin inhibiting Delta 5 desaturase activity. Sesamin, however, ha d little effect on the content and ratio of 20:3n-6 and 20:4n-6 fatty acids in neoplastic cells indicating that Delta 5 desaturase activity was low in these cells. Thus, sesamin is an effective compound for red ucing Delta 5 desaturase activity in non-neoplastic cell cultures and could be used to manipulate the content of series 1 and 2 prostaglandi ns derived from 20:3n-6 and 20:4n-6, respectively. (C) 1998 John Wiley & Sons, Ltd.