Melatonin
Regulation of Tumor Growth and the Role of Fatty Acid Uptake
and Metabolism by David E. Blask, Leonard A. Sauer and Robert T. Dauchy
Introduction
Dietary and hormonal factors play an important role in both
the stimulatory and inhibitory control of neoplastic growth
in experimental animal models of tumorigenesis (Rose, 1982).
Whereas dietary fat acts as a potent stimulus for tumor growth
(Klurfeld, 1995), compounds such as indoleamines, found in cruciferous
vegetables, exhibit antineoplastic properties (Wattenburg and
Loub, 1978). Similarly, hormones such as estrogens and prolactin
promote tumorigenesis (Welsch, 1985), while the pineal neurohonnone
melatonin, also an indoleamine, acts as an oncostatic agent
(Blask, 1993). Although melatonin has been shown to inhibit
cancer growth in a number of in vitro and in vivo experimental
tumor models (Blask, 1993), no definitive mechanism has been
established to explain its anticancer action, particularly
in vivo. OUT COmbined interests in the role of fatty acid
uptake and metabolism (Sauer et al., 1997) and melatonin (Blask,
1993) in tumor growth led to the novel hypothesis that dietary
fat and the photoperiod, as represented by the circadian melatonin
signal, are important environmental factors interacting at the
level of the cancer cell to regulate tumor growth.
