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Aim To study the mechanism of action of the new derivative of podophyllotoxin(LN-13)in indu-cing the apoptosis of K562/A02 cells.Methods The MTT method was taken to detect the inhibition of LN-13 and VP-16 on K562/A02 proliferation and inhibi-tion rate and IC50 values were obtained 48 hours later. The K562/A02 cell morphological change induced by LN-13 were observed through Hochest33342 and PI staining after 48 hours later.Flow cytometry was taken to detect the apoptosis of K562/A02 cells induced by LN-13.The reverse transcription-polymerase chain re-action was taken to detect the Bcl-2,Bax,caspase-3 and mdr-1 mRNA expression.The expression of P-gp was detected by Western blot.Results The growth of K562 /A02 cells was obviously inhibited by LN-13 when IC50 value was 3.32 μmol · L-1 .LN-13 could obviously induced cell apoptosis observed by Ho-chest33342 and PI staining.Flow cytometry detection showed that LN-13(2,4,8 μmol·L-1 )could induce cell apoptosis and apoptosis ratio reached 15.0%, 48.0%,68.96%,respectively.The reverse transcrip-tion-polymerase chain reaction showed that LN-13 in-creased the Bax and Caspase-3 mRNA expression,and meanwhile the expression of mdr-1 mRNA decreased. Western blot showed that P-gp expression was de-creased as the LN-13 dose increased.The data were significantly different from those of control group.Con-clusion Podophyllotoxin derivative LN-13 can induce the apoptosis of K562 /A02 cells,which may be close-ly-related to regulating P-gp expression and apoptosis related gene mRNA expression.
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Objective To explore the therapeutic efficacy of the water soluable photosensitizer D-galactopyranosyl zinc phthalocyanines (T1)-mediated photodynamic therapy (PDT) applied to HepG2 human hepatocellular carcinoma cells in vitro and in vivo,as well as its mechanism.Methods HepG2 cells in their logarithmic growth phase were cultured and divided into different concentrations ofT1 (0 μM,0.06 μM,0.125 μM,0.25 μM,0.5 μM and 1 μM).Methyl thiazolyl tetrazolium (MTT) assays were employed to determine the effect of the T1-PDT on the proliferation of the HepG2 cells.Cell apoptosis and necrosis were measured using a cell analyzer with Annexin VFITC/PI/Hochest33342 triple-staining.The reactive oxygen species (ROS) and the mitochondrial membrane potentials of the HepG2 cells were detected using fluorescence microscopy.Confocal microscopic assays were used to observe T1's subcellular localization on the HepG2 cells.Real-time quantitative polymerase chain reactions (RT-PCRs)were used to detect any apoptosis of Bcl-2-and Bax-related genes.H-22-bearing mice were used to calculate the antitumor rate of T1-PDT,and the expression levels of Bcl-2 and Bax mRNA were detected using RT-PCRs.Twenty-four healthy mice were randomly divided into a control group,a low-dose group,a middle-dose group and a high-dose group,each of 6.Each group was given different doses of T1-PDT and the tumor inhibition rate was calculated.Results The MTT assays showed that T1-PDT could significantly inhibit HepG2 cell growth,but T1 or PDT alone had little effect.The confocal microscope assay showed that T1 was mainly localized in the mitochondria in HepG2 cells with little in the lysosome.Cell analyzer results showed that T1-PDT could induce HepG2 apoptosis.The ROS levels of HepG2 cells increased after T1-PDT.The RT-PCR results showed that T1-PDT could increase the expression of Bax and decrease the expression of Bcl-2.The in vivo experiments demonstrated that T1-PDT significantly inhibited the growth of H-22-xenografied tumors.Conclusions T1-mediated PDT has a significant lethal effect on HepG2 cells in vitro and in vitro.The lethal effect of PDT on cancer cells is shown in the apoptosis and can be attributed to T1's subcellular localization in the mitochondria,increasing ROS levels,and regulating apoptosis-related genes.