Effects And Molecule Mechanisms Of Rapamycin On The Apoptosis Of Leukemia HL-60 Cells

objective: This experiment takes acute promyelocytic leukemia cells HL-60 as its object and aims to investigate the effects of Rapamycin on the apoptosis induction of HL-60 cells and the molecular mechanisms of apoptosis.Methods: The inhibitation of HL-60 cells by Rapamycin was measured by MTT assay. Morphic change of the apoptosis of HL-60 cells was observed by inverted microscope and light microscope, trapezoid straps by DNA agarose gel electrophoresis, and apoptosis rate by flow cytometry (FCM). Western-blot analysis was performed to detect the expression of Bax and Bcl-2 proteins after rapamycin treatment.Results: Rapamycin inhibited the generation of HL-60 cells depending on its concentration. The inhibition of rapamycin 80nmol/L equaled that of ATRA 10nmol/L. HL-60 cells after rapamycin treatment of 72 hours were observed to make typical apoptosis transformation, such as diminution, karyopycnosis, etc, through light microscope and AO/EB Fluophot. Detection of agarose gel electrophoresis was that DNA trapezoid straps were seen indistinctly when the density of rapamycin was 40 nmol/L, but clearly when the density increased to 80nmol/L. However, when the density rised to 160 nmol/L, hymenode cell death straps were also seen. Induction apoptosis of rapamycin 80nmol/L on HL-60 cells was detected through flow cytometry, and would not increase with rising density. It was after 72 hours of Rapamycin 80nmol/L treatment that distinct apoptosis was observed. Result of western-blot: With the extension of time, Bax/Bcl-2 was up-regulated with rise of apoptosis albumen Bax and fall of Bcl-2.Conclution: Rapamycin inhibited the proliferation of leukemia HL-60 cells dependent on density and time. The apoptosis mechanism may be assosiated with the up-regulation of the ratio between Bax and Bcl- 2.