Moore, M.M.*; White, J.V.; Williams, E.E.: Docosahexaenoic acid in cell membranes: vital for fish and fatal for cancer.

It is known that cells from fish maintained in cold water contain much higher amounts of docosahexaenoic acid (DHA) than cells of the same fish at warmer temperatures. DHA is also associated with the alleviation of many human diseases. In addition, it severely inhibits the growth of tumor cells. In all of these cases, there is evidence that the incorporation of DHA into cellular membranes is the common bond between these events. Thus, there seems to be a dichotomy of consequences to the presence of DHA in cellular membranes. Our research is focused on why DHA is lethal to tumor cells and beneficial to cold-water fish. We cultured murine leukemia cells (T27A line) at 37�C in various concentrations of DHA and measured proliferation rates and cell viability in order to verify the anti-cancer properties of DHA on this cell line. At concentrations below 150 mg/mL, DHA had no effect on either variable. At concentrations above 150 mg/mL, a significant reduction in both of these parameters was observed. For example, after four days of culture at 300 mg/mL DHA, only 22% of the cells present remained viable and cell numbers fell dramatically. Cells grown in the presence of oleic acid at the same concentrations and length of time grew at the same rate as control cells. These data confirm the sensitivity of this cell line to the anti-cancer effects of DHA. Currently, two sets of experiments are underway. The first set involves repeating the experiments on cells cultured at 27�C, a temperature decrease (10�C) known to cause an increase in the level of DHA in the membranes of fish cells. The second set uses fluorescent microscopy to determine the mode of death induced by DHA (apoptosis or necrosis). Combined, these data will allow us to assess the interdependence of DHA and temperature as it relates to cell survival.