gamma-linolenic acid induces apoptosis in B-chronic lymphocytic leukaemia cells in vitro

Gamma linolenic acid (GLA) is cytotoxic to many types of human cancer cells . Most chemotherapeutic agents are cytotoxic by inducing apoptosis. We exam ined the apoptotic activity of GLA on purified B-cells isolated from patien ts with B-cell chronic lymphocytic leukaemia IB-CLL) and from normal indivi duals. GLA significantly increased the degree of apoptosis in B-CLL B-cells after 24 hours of culture. The mean percentage of cells undergoing apoptos is when cultured in medium alone (spontaneous apoptosis) was 20% (range: 7 to 31%)(n=25) and in the presence of GLA ((5 mug-60 mug) was: 42%-95%. In t he presence of CLA 5 mug/ml and dexamethasone the degree of apoptosis was 8 6% (range: 72 to 100%). GLA induced apoptosis in B-CLL B-cells at a higher level than that observed with normal B-cells at all lower concentrations te sted 5, 10 and 15 mug/ml: P=0.045: 0.027 and 0.022, respectively. At 30 mug /ml of GLA. no significant difference in the percentage of cells displaying apoptosis between B-CLL and normal B-cells M;ns observed (P=0.075). GLA in duced apoptosis in B-CLL T-cells at both 10 and 30 mu /ml. The degree of ap optosis in normal T-cells with GLA was also significant at the higher conce ntration of 30 mug/ml. Interleukin 4 (IL4), a viability factor in B-CLL. an d vitamin E. an anti-oxidant, protected B-CLL B-cells against (20 mug/ml)-i nduced apoptosis. These results demonstrate that GLA induces apoptosis in B -CLL B- and T-cells cells in-vitro and that they are more susceptible to GL A-induced apoptosis than normal peripheral blued B- and T-cells.