The invention is directed to methods of inducing apoptosis, arresting cell cycle, or inhibiting cellular proliferation, or any combination thereof, in a tumor cell, by administration of an effective amount of an N-acyl homoserine lactone analog (AHL), optionally in conjunction with a tumor modulating agent such tumor necrosis factor (TNF) related apoptosis inducing ligand (TRAIL) to the patient. Novel bioactive analogs of an N-acyl homoserine lactone are also provided.