| Trichosanthin (TCS) is a basic protein, classified as a type-I ribosome-inactivating protein that cleaves specifically the N-glycosidic bond of A-4324 of 28S rRNA, found in the root tuber of Chinese herb Trichosanthes kirilowii Maxim.In 1998,TCS was accepted by our National Basic Drugs Catalog as an agent for birth control.In addition to terminating term pregnancy,it was also useful in treating ectopic pregnancy,hydatidiform mole and choriocarcinoma.TCS possesses a variety of biological activities,including abortifacient,immunoloregulation,anti-cancer activities and it is reported to be a potential therapeutic agent against HIV infection.TCS is highly toxic to mouse ascites reticulocyte sarcoma,mouse cervical cancer,melanoma,liver cancer and other digestive tract cancer. Hepatocellular carcinoma is one of the most common malignancies in our country.Although the surgical resection is the first treatment of choice, the survival rate for HCC after resection remains low because of the high recurrent rate. The common way for prevention and treatment of recurrent cases is postoperative transcatheter arterial chemoembolization, associated with immune modulators or Chinese herbal medicines.Unfortunately, there is less effective agents to choose.Resistance to chemotherapeutic drugs is a principal problem in the treatment of cancer.The conditions are even worse when we use certain chemotherapeutic drug too long.At the same time,there are more patients almost have no therapeusis when they cannot operate.Our study is to evaluate whether TCS could inhibit tumor growth and metastasis,and explore the mechanisms of cooperation with bio-regulation drugs.Section I:Studies on the intervention on tumor growth and metastasis of hepatocelluar carcinomaI.Cytotoxicity to liver cell lines and HCC cell lines The cytotoxicity of TCS was assessed in vitro on three different cell lines: human liver cell lines (L-02), hepatocellular carcinoma cell lines with high orlow metastatic potential (MHCC97H and MHCC97L).TCS was diluted into three different concentration gradients with the culture medium. TCS of different concentrations were inoculated to 1.5×103 cells at their logarithmic phase of growth in 0.15 ml complete medium in the wells of a flat-bottomed 96-well microtitre plate.After 72h culture, the growth inhibitory activity of TCS was assessed by the MTT assay.It showed a significantly cytostatic activity to MHCC97H and MHCC97L cells compared with control group within 2.5μg/ml to 160μg/ml. The maximum growth inhibition rate was nearly 80% at 160μg/ml. MHCC97H and MHCC97L were sensitive to TCS , while L-02 was less susceptible.The IC50 values of L-02,MHCC97H and MHCC97L were 21.1,6.9 and 5.0μg/ml,respectively. There was a significant difference between the tumor cells and normal liver cells(P<0.05). It revealed that the doses ,which are efficient to inhibit tumor growth ,is safe to normal liver cells. Short-term cytotoxicity test of MHCC97H with TCS(2.5μg/ml,5μg/ml,10μg/ml,20μg/ml,40μg/ml,80μg/ml and 160μg/ml) was performed for 6,12 and 24 hours. There was no significant difference among these three groups. The effect of cytotoxicity was mild and the maximum growth inhibition rate was 26.2%. II.Therapy with TCS inhibits tumor growth in LCI-D20 nude mice model Metastatic model of human hepatocellular carcinoma in nude mice(LCI-D20) was established via orthotopic implantation, all mice with transplanted tumors exhibited 100% transplantability and metastasis. 42 nude mice,orthotopically implanted by tumor tissues from LCI-D20, randomized into 5 groups.The first group had 7 mice which were injected with TCS 0.4 mg/kg,qd.The second group had 7 mice which were injected with TCS 0.2mg/kg,qd.The third group had 7 mice which were injected with TCS 0.4mg/kg,qod.The fourth group had 7 mice which were injected with TCS 0.4mg/kg,q3d . The 14 control mice were injected with normal saline. TCS at different doses was administered to abdominal cavity for 35 consecutive days.Th...
|
PDF Full Text Request