文本框: THE STUDY ON THE EFFECT OF NFkB IN TNF-a INDUCED APOPTOSIS IN HUMAN LEUKEMIC CELL LINE HL-60 Tang AP, Peng GJ, Chen WH,Hu Q,Liu SY, Zhang LQ, Wang LY Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China Objective: To investigate the role of NF-kB in TNF-a induced apoptosis of HL-60 cells. Methods: A mutant IkBa (S32,36®A) was transfected into HL-60 cells by lipofectin tranfection and its transient effect was examined 48 hours after transfection. The activation of NF-kB was detected by immunol fluorescence cytochemistry with FITC-tagged p65 antibody. The nuclear extracts of transfected and untransfected cells were analyzed by western blot with anti-p65 antibody. The apoptosis of transfected and untransfected HL-60 cells induced by TNF-a was measured by a FACScan side scatter analysis. MTT was used to measure the rate of cell inhibitition initiated by TNF-a. Results: NF-kB/p65 associated fluorescence can be seen in the nuclei of untransfected cells, no such fluorescence were seen in transfected HL-60 cells. After TNF-a stimulation, the protein bands stand for nuclear NF-kB/p65 from untransfected cells were detected on nitrocellulose. As for transfected HL-60 cells, the protein bands were not detected. The percentages of apoptosis induced by TNF-a in transfected cells were significantly more higher than that of untransfected HL-60 cells (P<0.01). The inhibititing rate of transfected cells initiated by TNF-a was significantly more higher than that of untransfected HL-60 cells (P<0.01). Conclusions: The activation of NF-kB involves in the resistance of HL-60 cells toward apoptosis induced by TNF-a. The mutant IkBa can attenuate the resistance of HL-60 cells and increase its’ sensitivity to TNF-a by inhibiting NF-kB activation. 0975