Prostaglandins (PGs) are bioregulatory substances and are widely distributed in a variety of tissues. Numerous facts have been described in relation to
cancer biology with PGs. The purpose of our study lies in the creation of anti-
tumor PGs. We have described that
PGD2 has strong cell growth inhibitory activity; furthermore, we discovered that
PGJ2, 9-deoxy-delta 9-PGD2, has 3 times stronger activity than the mother compound,
PGD2. In vivo experiments showed that only
PGA2 and
PGJ2 exert antitumor activity. Thus,
cyclopentenone ring structure in PG seems to be an essential moiety for cytotoxicity of PG. On the basis of the above facts, we propose tha name of
antineoplastic PGs for
PGA and PGJ derivatives which have
cyclopentenone ring. Recently, we developed several
antineoplastic PGs which showed IC50 value less than 0.3 microgram/ml against
L1210 leukemia cells, and these compounds also showed antitumor activity against
Ehrlich ascites tumor in vivo comparable to that of
cyclophosphamide. The action mechanism seems to be in its alkylation activity of the
cyclopentenone structure and not in
receptor-cAMP route. Spectrum of anti-
tumor activity and its toxicity in vivo are now under investigation. In this brief review, mainly our recent approaches in this field are discussed.