ABSTRACT
Objective To observe the inhibitory effect and mechanism of 9-nitrocamptothecin liposomes on HepG2 liver carcinoma cells. Methods HepG2 cells were incubated with 9-nitrocampto-thecin(9NC) or with 9-nitrocamptothecin liposomes(9NC-LP) for 24 h, 48 h and 72 h. Cell viability was then measured by the MTT assay. Cell cycle and apoptosis were evaluated by flow cytometry.Western Blot was used to determine the expression of cell cycle and apoptosis related proteins. HepG2tumor-bearing mouse models were then established. The HepG2 tumor-bearing mice were randomly divided into control group, free liposomes group, DMSO group, 9NC low dose group, 9NC high dose group, 9NC-LP low dose group and 9NC-LP high dose group. There were 10 mice in each group.Drugs were administered by tail vein and tumor volume and body weight were observed 28 days after administration. Then animals were sacrificed and the expression of proteins from tumor homogenates was analyzed by Western blotting. Results In vitro, HepG2 cell viability was apparently inhibited by 9NC and 9NC-LP, and the inhibitory effect increased in a time-dependent and dose-dependent manner.Both S and G2/M phase arrests were observed after incubation with drugs. HepG2 cells were completely arrested in S phase with 9NC concentration over than 0.1 μmol/L after incubation for 24 h,while more than 95% of cells arrested in G2/M phase when 9NC concentration was 0.1 μmol/L after incubation for 72 h. In vivo, compared with the control group, the average tumor volume was reduced in both the 9NC and 9NC-LP group (P50% of animals died 14 days after drug administration. Conclusion 9NC and 9NC-LP can inhibit HepG2 cell growth via cell cycle arrest and apoptosis induction. 9NC-LP has a more potent anti-tumor effect and fewer side effects in vivo,which means 9NC-LP is a promising compound for cancer therapy via intravenous administration.
ABSTRACT
Objective To investigate the modulating effects and explore their mechanism of 9-nitrocamptothecin and its liposomes to induce apoptosis and inhibit cell cycle in HepG2 and L02 cell lines. Methods Cells were incubated with 9-nitrocamptothecin(9NC) or with 9-nitrocamptothecin liposomes for 24 h, 48 h and 72 h, then, the cell viability was measured via MTT assay; cell cycle and apoptosis was evaluated by flow cytometry after stained by PI and Annexin V-PE/7AAD. Additional, Western Blot was used to evaluate the expression of cell cycle and apoptosis related protein. Results Both cells viability were apparently inhibited by the 9-nitrocamptothecin and 9-nitrocamptothecin liposomes, the inhibitory effect showed a time-dependent and dose-dependent manner. Both S and G2/M phases arrest were observed after incubated with drugs. HepG2 cell was completely arrested in S phase when 9NC concentration over than 0. 1 μmol/L after incubation for 24 h, while more than 95% cells arrested in G2/M phase when 9NC concentration is 0. 1 μmol/L after incubation for 72 h. Apoptosis induction effect also showed a time-dependent and dose-dependent manner. Western Blot results showed the expression of Bax and Caspase-3 were upregulated while Cyclin A, Cdk2, Cyclin E and Bcl-2 were downregulated. More importantly, the compounds were more cytotoxic to the cancer cell lines than to the normal liver cell. Conclusions 9-nitrocamptothecin and 9-nitrocamptothecin liposomes can potently inhibit cell growth via regulation of cell cycle and induction of apoptosis, and this effect was preferentially in cancer cell. Inhibitory of 9-nitrocamptothecin liposomes was slightly better than the 9-nitrocamptothecin.
ABSTRACT
20(S)-9-nitrocamptothecin was synthesized from camptothecin by nitration reaction using mixed nitrate salts in sulfuric acid medium.The yield was raised from 31% to 40% after chromatographic purification treatment.The best reaction conditions was as follows:0.5 g of camptothecin;30ml of sulfuric acid;0.007mol of nitrate salts(NH4NO3/CaNO3=1/1).The reaction was completed in 24h at 20℃.The advantage of this method is high yield and easily purification.