Study On The Effects Of Homoharringtonine To Acute Promyelocytic Leukemia Cell Line-NB4 Cells

Homoharringtonine(HHT)is a plant alkaloid with antileukemic activity which is currently being used for treatment of acute and chronic leukemias.The present studies have evaluated the effect of HHT on proliferation and apoptosis in treating human acute myeloid leukemias. Acute promyelocytic leukemia(APL)is characterized by a specific chromosome translocation t(15;17).NB4 cell viability was measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide(MTT) assay.The PML/RAR a oncoprotein expressing level was measured by Real-Time PCR assay.We found that HHT significantly inhibited the proliferation of human acute promyelocytic leukemias cell lines in a time-dependent manner.The growth-inhibitory IC50 values were 420.059ng/ml,103.008ng/ml,31.628ng/ml after the treatment of triptolide for 24,48,72 hours,respectively.And it can also have a synergetic effect with arabinoside.We detected this apoptotic process was associated with the downregulation of the level of the PML/RAR a oncoprotein expressing. These findings indicate that HHT may be effective in the treatment of human acute promyelocytic leukemias with less side effect.Maybe HHTcan be a novel treatment of relapsed or refractory acute promyelocytic leukemia...