Awad is an associate professor in the Department of Physical Therapy,
Exercise and Nutrition Sciences in the UB School of Health Related
Professions. He and colleagues at UB have been trying to understand
the mechanisms responsible for vegetarians' lower rates of hormone-dependent
cancers, and for the lower mortality rate from such cancers in Asian
countries, where populations eat little meat.
With fats known to play a role in the development of several cancers,
Awad's group has been focusing on the phytosterols for possible
answers. He reported at an international conference on cancer research
in Greece last October that the phytosterol B-sitosterol appears
to play a role in inhibiting the growth of human prostate-cancer
cells by strengthening an intracellular signaling system that inhibits
An earlier study by Awad published in 1998 in the Journal of Nutritional
Biochemistry reported that plant-based fats may cut the risk of
prostate cancer by reducing the levels of testosterone and certain
enzymes that metabolize testosterone into more active forms.
"If we know how phytosterols work, we can advise people how to
modify their diets to reduce their risk of cancers, or we could
eventually design drugs to target systems they influence," Awad
noted. "Meanwhile, these findings reinforce the importance of including
large amounts of vegetables in the diet."
In the current work, Awad's research team examined the effect of
B-sitosterol and another prevalent plant fat, campesterol, on the
growth of a particular line of estrogen-independent breast cancer
cells, designated MDA-MB-231. Cell cultures were supplemented with
either of the two plant fats or cholesterol. A control culture received
no supplementation. Cell counts after five days showed that cultures
supplemented with B-sitosterol had 66 percent fewer breast-cancer
cells than controls or cultures supplemented with cholesterol or
campesterol. B-sitosterol had no effect on the activity of an enzyme
called PP2A, which was found in his previous study to play a role
in reducing prostate-cancer cell growth.