The Study Of Anti-cancer Activity And Mechanism Of Its Action Of The New Hepatoprotectant-Sy-801

It is well known that the pathogenesis of primary hepato-carcinoma is closely related to chronic virul hepatitis. If an anti- hepatitis drug could inhibit tumor growth and/or retard hepato-carcinogenesis, the value of this kind of anti- hepatitis drug would be very great. Sy-801,a new hepatoprotectant developed by our institute, has been shown to have hepatoprotective action with high efficacy and low toxicity.Sy-801 p.o could significantly inhibit the growth of Lewis lung carcinoma in a dose-dependent manner. The inhibition rate of Sy-801 300 mg/kg reached to 48.8%, and obviously reduce DNA content of the carcinoma tissue. The survival time of leukemia L1210 was prolonged by Sy-801, though the prolonged time was not so long,it is still valuable as the drug was given orally. Sy-801 also inhibited the growth of H22 hepatoma, its inhibiting rate at large dose was crresponding to 60 mg/kg of cyclophosphamide. The inhibition of H22 hepatoma by Sy- 801 in combination with cyclophosphamide was stronger than one of them given alone. The DNA content of H22 hepatoma was significantly reduced by Sy-801 too. Sy-801 was shown to markedly raise the activity of NADPH-cytochrome C reductase and GSH content in livers of mice bearing with H22 hepatoma, indicating that Sy-801 has the effect on drug metabolism system, whereas Sy-801 only increased the activity of NADPH cytochrome C reductase of carcinoma tissue, but had no effect on the GSH content of carcinoma.The results showed that HL-60 cells were induced to differentiate along granulocyte lineage by 10^-4 M Sy -801. DDB in vitro. Either of them could inhibit the growth of HL-60 cells; Over forty percent of the HL-60 cells treated with Sy-801 and DDB for six days, exhibited NBT reduction, and the phagocytesis activity was also inhanced by the treatment of Sy-801 and DDB for four days. The HL-60 cells treated with Sy-801 and DDB were turned to be mature morphologically. Most of the matured cells were in myelocytic or metamyelocytic stage and a few of the cells were in banded or segmented stage. It was observed that the control HL-60 cells showed round nuclei, large and obvious nucleoli, which those treated with Sy-801 and DDB for four days showed cell and its nucleus shrinkage, and nucleoli disappear. The activity of acid phosphatase in the treated HL-60 cells was significantly increased. Flow cytometry indicated that the cells treated with 10^-4 M Sy-801 were blocked in S phase.The results also showed that Sy-801, DDB inhibited the growth and clone forming of human hepatoma Bel -7402 cells and induced the cells differentiation in vitro. The secretion of alpha-fetoprotein (α-FP) and the activity ofγ-glutamyl transpeptidase (γ-GT) in Bel-7402 cells were decreased; While the secretion of albumin and the activity of tyrosine transaminase(TAT) were increased. These results proved that Sy-801 and DDB changed the BEI-7402 cells biochemically. It was also found that the morphology of Bel-7402 cells treated with Sy-801 and DDB were changed. The nuclear size and ratio of nucleus and cytoplasm was decreased, and cytoplasm substances were increased. Sy-801 and DDB at the concentration of 10^-4 M could significantly increase the content of cAMP and CaM in Bel-7402 cells , and inhibited topoisomeraseâ…¡activity and the incorparation of ³H-TdR and ³H-UR into Bel-7402 cells. With Northern blot analysis, It was found that Sy-801 (10^-4 M) could reduce c-myc, N-ras oncogene expression of Bel-7402 cells, and induce anti-oncogene p53 expression, as well as reduce AFP gene expression of hepato-carcinoma marker.We took the lead in developing apoptosis used to study the anti-cancer mechanism of Sy-801. the results showed that Sy-801 or DDB at the concentration of 10^-4 M induced apoptosis of HL-60 and Bel-7402 cells. It was found that Sy-801 induced typical cellular changes including, nuclear condensation,apoptosis body and nuclear rupture, the apoptosis of HL-60 and Bel-7402 induced by Sy-801 was direct to its influence on nucleus, and could be reduced by Zncl²(2 mM) and TPA (10 nM). ZnCl² (2 mM) could antagonize the morphological changes of Bel-7402 cells induced by Sy-801, It was also first found that retinoic acid and Ca⁺⁺had direct effect on nucleus and induced apoptosis of nuclei HL -60 cells.In conclusion, the hepatoprotectant Sy-801 has anti -cancer activity, particularly Sy-801 inhibiting alpha -fetal protein secretion and its gene expression of hepatoma Bel-7402 cell line, which provides a sound scientific basis, not only for applying Sy-801 in the treatment of chronic virul hepatitis, but also for the potentiality of using Sy-801 for prevention and even treatment of hepatoma.