Study On The Mechanism Of Ginkgetin Agains Chronic Myeloid Leukemia Cell Line

Background:Chronic myeloid leukemia is a clonal malignancy derived from hematopoietic stem cells.It is characterized by excessive proliferation of myeloid progenitor cells harboring Ph chromosome.CML is divided into three phases,i.e.chronic,accelerated and blastic phase.With the introduction of tyrosine kinase inhibitors(TKIs),most CMLs are well-controlled,however,drug resistance still occurs in some CMLs.Thus,search for novel anti-CML agents is greatly needed.Previous studies have shown that Ginkgetin is an anticancer agent against many cancers.However,its effectiveness in CML remains unknown.The present study aims to evaluate the effects of ginkgetin on the growth of K562 cell line and delineate its mechanism of action.Methods:The MTT assay was used to examine the proliferation of K562 cells,and a terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labeling(TUNEL)staining was conducted to measure the percentage of apoptotic cells.Furthermore,changes in tumor necrosis factor-a(TNF-a)level were detected by Western blot analysis.A tumor bearing mice model was employed to investigate the anticancer effect of ginkgetin in vivo.Results:Ginkgetin inhibited K562 cell proliferation in a dose-and time-dependent manner.Concentrations of ginkgetin required to induce 50%death of K562 at 24,48 and 72 h were 38.9,31.3 and 19.2 μM,respectively.Moreover,ginkgetin induced K562 apoptosis in vitro along with increased levels of TNF-a.Interestingly,anti-TNF-α antibody prevented ginkgetin-induced K562 cell apoptosis and growth inhibition via deactivation of caspase-8,caspase-9 and caspase-3.Concomitantly,downregulation of TNF-α by etanercept in vivo attenuated ginkgetin-induced inhibitory effects on the tumor growth in a xenograft mouse model.Conclusion:Our results suggest that ginkgetin effectively inhibits CML in vitro and in vivo,and TNF-α pathway plays a key role in ginkgetin-induced CML inhibition.