The cytotoxic effect of metformin correlated with intracellular reactive oxygen species reduction, activation of AMPK, the inhibition of pro-survival pathways such as mTOR and STAT3 and the down-regulation of v-FLIP, a latent viral antigen that also plays a pivotal role in PEL cell survival.
Using an antibody against v-FLIP we have detected expression of the endogenous protein in latently infected KSHV-positive primary effusion lymphoma (PEL) cell lines.