| Background and objective:Leukemia as a common malignant tumor of origin hematopoieticprecursor cells, has a higher morbidity in our country. Currently the maintreatments for leukemia are hematopoietic stem cell transplantation andchemotherapy. Chemotherapeutic drugs are synthetic, which have may toxicside effects, so there is an urgent need for drugs with better therapeutic effectsand less side effects. Traditional Chinese medicine as a traditional treatment ofleukemia has the obvious advantages. The practice has proved that traditionalChinese medicine has an important role in the treatment of leukemia. Juglone isactive substances belonging to the naphthoquinone, which exists in theJuglandaceae plants and other black walnut. It is mainly used for antitumoraltherapy. Walnut bark has been made as a proved recipe of anti-cancer in manycountries and regions. The effect of juglone on leukemia has not beenintensively studied and its exact mechanism of action has not been clarified. Inthe present study, the inhibitory effect of juglone on proliferation and inductionof apoptosis were observed in five kinds of human leukemia cells. The aim ofthis study was to explore the application value of juglone in leukemiatreatment.Research methods:The morphological changes of K562cells were observed by invertedmicroscope. MTT assay was used to detect the inhibitory effects of juglone ongrowth of K562, Jurkat, U937, U266and NB4leukemia cell lines. Theinduction of apoptosis in juglone-treated K562cells was evaluated employing flow cytometry with Annexin V/PI dual-staining. Western blot was used todetect expression of Bcl-2proteins in juglone-treated K562cells.Results:1. Cell morphology: an inverted microscopic observation, the controlgroup of K562cells showed normal appearance: suspended growth, in goodcondition, cell density uniform, the same size, clear outline. Low concentrationof juglone-treated K562cells for24hours showed typical apoptoticmorphological changes, such as, the cell density sparseness, cell shrinkage,sizes, unclear contours, refraction. High concentration of juglone-treated K562cells had visible cell debris, indicating that the cells growth was inhibited.2. MTT assay results: Juglone revealed a strong inhibitory effect onproliferation of leukemia K562, Jurkat, U937, U266and NB4cells. Theinhibitory effect on growth of Jurkat and U266cells was the most obvious.Median inhibitory concentration (IC50) in the other three kinds of leukemiacells（K562、U937and NB4）was less than40mg L-1. The action was moreobvious with increasing concentrations of juglone and prolonging of treatmenttime, showing a concentration-and time-dependent manner.3. The results of flow cytometry with Annexin V/PI dual staining: Theproportion of apoptosis in K562cells was gradually increased with theincreasing concentrations of juglone. The apoptotic rates(%) were4.54±0.6,11.54±0.6,28.7±0.3,45.0±1.2and76.1±1.4, respectively, in juglone(concentrations:1,2,4,8and16mg·L-1)-treated K562cells for6h, indicatingthat juglone induced apoptosis in K562cells. The action of induced apoptosiswas enhanced with increasing concentrations of juglone. The results revealedthat the inhibitory effect of juglone on proliferation in leukemia cells may bedue to juglone promoted apoptosis.4. Western blot: juglone reduced anti-apoptotic protein Bcl-2expression, in K562cells.Conclusions:1. Juglone inhibited growth of leukemia cells certified under microscope.2. Juglone had a strong inhibitory effect on proliferation of leukemia K562,Jurkat, U937, U266and NB4cells, and showed a time-andconcentration-dependent manner. The inhibitory effect was the most obvious inJurkat and U266cells.3. Juglone treatment induced apoptosis in K562cells, and the effect wasenhanced with increasing concentrations of juglone.4. Juglone reduced anti-apoptotic protein Bcl-2expression, suggestingjuglone induced apoptosis.These results suggest that juglone may be a useful therapeutic agent forthe treatment of leukemia. |
PDF Full Text Request