The Effect Of Dexamethasone And Thalidomide On Tumor Growth In Mouse H₂₂ Model

Objective: Tumor is a main reason for die of disease, and the mortality of original hepatoma is highest in malignant tumors. At present, surgery removal is still the most useful method of hepatoma treatment, but only 5.4 %~24.3 % of sufferer has opportunity to do the operation. Now, there still has no ideal curative effect on medium or late hepatoma with traditional chemical therapy or radiation therapy. In 1970's, Folkman brought forward a novel anticancer strategy-anti-angiogenesis based on the phenomena that cancer growth is accompanied with neovascularization. Then it has been proved that tumor growth, development and metastasis did depend on neovascularization. Now more and more peoples have accepted the anti-angiogenesis strategy. Even in treatment to leucocythemia, anti-angiogenesis method has some effect. In vivo, angiogenesis is concerned with many physiological and pathological courses, such as female reproductive system, wound healing, growth and metastasis of tumors. Anti-angiogenesis is just to reject or weaken the neovascularization induced by tumor cells. Compared with traditional chemical and radiation methods, anti-angiogenesis in usually does not injure normal vessel and has less side effects; moreover, the therapy directing to endothelial cells, in theory, has no or little acquired resistance, and in mechanism the therapy fits to all kinds of solid tumors. Because of those reasons, a very good future of anti-angiogenesis strategy is shown in curing cancer. Most of hepatoma depends on angiogenesis, so it is presumed that anti-angiogenic therapy will have better effect in treating hepatoma. Furthermore, if the liver artery ligation or embolus to some suffers having the inoperable larger hapatoma were combined with anti-angiogenic treatment, the opportunity of operation for these patients would be increased. In reports, some drugsthat have already been used in other diseases have the anti-angiogenesis and anti-tumor activity too, but the exact curative effect, molecular mechanism and the scope of application are still unknown. In those opinions, we detected the effects of some drugs on tumor growth and angiogenesis of grafted Hi2 cells in mouse to study the possibility of them to cure hepatoma.Methods and results:1. Drug screening: The effects of five drugs, dexamethasone, thalidomide, protamine, heparin and aspirin, on cell proliferation and VEGF expression in cultured H22 cells, normal hepatic cells, and human umbilical vein endothelial cells (ECV-304) were observed. The proliferation experiment suggested the direct inhibition of drug to the cells; the VEGF expression suggested the ability of drug to inhibit angiogenesis; we also observed the effects of three dosages of drugs on tumor growth in mouse H22 model to judge the efficiency of drug inhibition. Methods: 1) Proliferation in vitro: H22 cells, normal hepatic cells and ECV-304 cells were suspended at a concentration of 1X105/ ml in 20 % NBS-DMEM or in 1 % NBS-DMEM medium. The cell suspension was distributed into 96 micro well plates. Each well included 100 ul of cell suspension, 20 ul of drug at different concentrations and 80 ul of relevant culture medium, then the final volume was 200 ul. In control wells 20 ul normal saline was substituted for drug solution. After 48 h in culture, the absorbency was detected at 550 nm by MTT method. The last concentration of dexamethasone was 9.68 umol/L, 24.21 umol/L, 48.41 umol/L, 96.82 umol/L, 242.06 umol/L, 484.12 umol/L, and 968.24 umol/L; of protamine was 10 mg/L, 25 mg/L, 50 mg/L, 100 mg/L, 250 mg/L, 500 mg/L, and 1 000 mg/L; of heparin was 5 U/ml, 12.5 U/ml, 25 U/ml, 50 U/ml, 125 U/ml, 250 U/ml, and 500 U/ml. Thalidomide and aspirin were added only in 20 % NBS-DMEM when H22 cells and ECV-304 cells were cultured. After 48 h, cell counting was done with microscope. The last concentration of thalidomide was 0.19 mmol/L, 0.48 mmol/L, 0.97 mmol/L, 1.94 mmol/L,104.84 mmol/L, 9.68 mmol/L, and 19.36 mmol/L; of aspirin was 0.67 mmol/L, 1.67 mmol/L, 3.33 mmol/L, 6.66 mmol/L, 16.65 mmol/L...