Hyperthermia enhances tumor necrosis factor α-induced apoptosis of a human gastric cancer cell line

We have investigated the effects of hyperthermia on the apoptosis induced by tumor necrosis factor α (TNF-α). Confluent monolayers of human gastric cancer cell line MKN45 were either treated or untreated with hyperthermia for 1 h. The cells were subsequently stimulated with TNF-α. A 24-h incubation with TNF-α did not affect cell viabilities; however, pretreatment with hyperthermia significantly enhanced the level of apoptosis induced by TNF-α. Pretreating MKN45 cells with hyperthermia (42.0 °C) significantly inhibited the TNF-α-induced increase in the binding activity of NF-κB to DNA. This study suggests that hyperthermia can inhibit the TNF-α-induced NF-κB activation and that hyperthermia renders human gastric cancer cells susceptible to the TNF-α-induced apoptosis, possibly via inhibition of the NF-κB pathway.