THC, HU-210, and anandamide, but not WIN55212, induce apoptosis in EL-4 tumor cells in vitro.

(A) EL-4 tumor cells were cultured in serum-free medium for 4 hours in the presence of vehicle, THC (3 μM), WIN55212 (3 μM), and HU-210 (3 μM). The level of apoptosis was quantified by annexin/PI staining, as described in Figure 3. (B) EL-4 tumor cells were cultured in serum-free medium for 4 hours in the presence of vehicle or anandamide (5 and 10 μM). The level of apoptosis was quantified by TUNEL assay.