Abstract: In the present investigation, the cytotoxic activity of tumor necrosis factor was studied on proliferation of human lung cancer cells in vitro. After the MTS were cocultured with TNF (10⁴U/mL), data presented showed the suppressive effects of TNF on MTS of A549(P<0.05). Twenty four hour exposured of the A549 cell line with TNF (10⁴U/mL), the growth curve, the population doubling time and the plating efficiency were tested. After pretreatment with TNF, it shifted the growth curve of A549, the population doubling time increased from 37 h to 43 h, but the plating efficiency was decreased from 52 percent to 15 percent. The proliferation of the stem cell of A549 the human lung cancer cell lines could be inhibited by TNF.

Key words: tumor necrosis factor α, lung cancer cell, multicellular tumor spheroid (MTS), population doubling time, plating efficiency