| Objective: Gastric cancer is one of the most common malignant tumors in China and the world. By so far, the incidence and mortality of gastric cancer rank second in the world, although the morbidity and mortality of gastric cancer have decreased in some countries and regions. Gastric cancer has many characters as follows: hidden incidence and the low rate of early diagnosis, surgical resection and long-term survival, so its clinical effect is not very good. Advanced gastric cancer patients have lost the chance of localized therapy, such as surgery or radiotherapy. The primary therapy of gastric cancer is systemic chemotherapy, but there is no accepted or standard chemotherapy program. Molecular targeted drugs has become the new developed direction to treat cancer. Recombinant human endostatin is one kind of molecular targeted drugs. Program of recombinant human endostatin (Endostar, YH-16) combined with NP (Vinorelbine+Cisplatin) has been widely used in non-small cell lung cancer. This program has gained obvious effect and significant improvement on the quality of life in advanced lung cancer patients. At present, YH-16 combined with chemotherapy to treat except lung cancer is on studying of basic and clinic. YH-16 prevents the angiogenesis of tumor, inhibits the growth of tumor and promotes the apoptosis of tumor cells. LF program of Leucovorin (LV) and Fluorouracil (5-Fu) is a recognized chemotherapy program for the treatment of gastric cancer. 5-Fu is a kind of antipyrimidine which belong to antimetabolite drugs. 5-Fu plays its major role on cells of S phase and its sensitizer is LV. LV combined with 5-Fu can kill tumor cells, and reduce the secretion of growth factor which related with angiogenesis, and reduce the angiogenesis of tumor. YH-16 and LF attack respective group of tumor cells to diminish the volume of tumor. This makes the program of YH-16+LF reasonable in the treatment of gastric cancer. In this study, the mice gastric cancer line MFC were implanted subcutaneously in C57 mice, YH-16+LF were applied to treat the transplantation tumor of gastric cancer, the mechanism of its suppress and destruct on tumor were studied. This study provides experimental evidence for the clinical application of the program.Methods: The mice gastric cancer line MFC was implanted subcutaneously in healthy C57 mice. 40 successful model mice were divided into 4 groups randomly and there were 10 mice in each group. The mice of control group were injected with normal saline intraperitoneally for consecutive 14 days; the mice of YH-16 group were injected with YH-16 0.8 mg/Kg intraperitoneally for consecutive 14 days; the mice of LF group were injected with LV 10 mg/Kg and 5-Fu 20 mg/Kg intraperitoneally for consecutive 5 days; the mice of YH-16+LF group were injected intraperitoneally with LV 10 mg/Kg, 5-Fu 20 mg/Kg for consecutive 5 days and YH-16 0.8 mg/Kg for consecutive 14 days. The general state of health were observed daily and the tumor volume were measured every 2 days. At the 22th day of the experiment, tumor volume growth curve were drew, the tumor volume and weight inhibition rate were calculated and the paraffin sections were prepared for H.E. staining and immunohistochemistry. The expression of vascular endothelial growth factor (VEGF), microvessel density (MVD) and apoptotic factors (Fas) in tumor tissue of mice were detected by immunohistochemistry.Results:1 The changes of tumor volume.The tumor volume increased gradually in control group, and reached 1029.32±91.40mm3 at the 22th day. Treated groups included YH-16 group, LF group and YH-16+LF group. The tumor volume of treated groups showed a increased-downward trend. The tumor volume gradually decreased after 10 days. The tumor volume were 259.01±75.44mm3, 179.49±72.54mm3, 93.31±55.79mm3, and the inhibiting rate of tumor volume were 74.84%, 82.56%, 90.93% respectively in treated groups at the 22th day. Compared with control group, there were significant increases in treated groups (P<0.01). There were a significant difference among treated groups (P<0.05). 2 The inhibiting rate of tumor weight.Inhibiting rate of tumor weight of treated groups were 43.04%, 75.98%, 87.53%, respectively. Compared with control group, there were significant increases in treated groups (P<0.01). There were significant difference among treated groups (P<0.01).3 The interaction between the drugs of YH-16 and LF. The effect of the program of YH-16+LF was synergistic.4 The changes of the behavior of mice.In the course of medication, mice of YH-16 group moved quickly and took in food and water freely. There was no obvious adverse reaction in YH-16 group, so they had good mental state. LF and YH-16+LF groups reduced food and water taking-in slightly and had no vomiting. They also moved quickly and did not decreased weight obviously. With the gradual growth of the nodules of transplanted tumor, their consumption of food and water and weight were obviously reduced and movement got slowly in control group of mice, so they had bad mental state.5 Changes of pathologic histologyThe diameter of tumor cells became larger and large areas of necrotic cells could be seen in the center of tumor. H.E. staining showed non-homogeneous structure of red dye, where few residual tumor cells without necrosis could be seen. Inequality of size and paratypical nuclear tumor cells could be seen. Compared with control group, histopathological changes in the treated groups had statistically difference (P<0.01). There were significant difference among treated groups (P<0.05).6 Protein expression of VEGFProtein expression of VEGF of each group was 68.50±14.25%, 39.81±13.64%, 52.13±14.96%, 15.51±8.28%, respectively. Compared with control group, protein expression of VEGF was markedly decreased in treated groups (P<0.05). There were significant difference among treated groups (P<0.05).7 Protein expression of Fas.Protein expression of Fas of each group was 5.62±4.06%, 12.01±4.47%, 32.92±8.47%, 48.61±7.01%, respectively. Compared with control group, protein expression of Fas was markedly increased in treated groups (P<0.05). There were significant difference among treated groups (P<0.01).8 The MVD counts.The MVD counts in each group were 9.51±1.24, 2.54±0.86, 4.15±1.08, 1.28±0.68, respectively. Compared with control group, MVD counts were markedly decreased in each treated group (P<0.01). There were significant difference among treated groups (P<0.01).Conclusion:1 The model that mice gastric cancer line MFC was implanted subcutaneously in C57 mice, which had the character, such as the better controllability and comparability on operation, the higher successful rate of transplantation, the shorter time of developing into a cancer. In addition, there was no phenomenon of spontaneous regression.2 YH-16 combined with LF program had reasonable and synergistic effect on implanted gastric cancer in mice.3 There was obvious inhibitive and lethal effect through the therapy of YH-16+LF program on implanted gastric cancer in mice. YH-16+LF program had significant short-term effect. The combination did not increase the side effect of chemotherapeutical drug.4 YH-16 played a part in the therapy by reducing expression of VEGF protein, preventing migration of vascular endothelial cell, inhibiting angiogenesis of tumor, decreasing counts of MVD and blocking nutrient supply of tumor. LF played a part in the therapy by killing tumor cells. YH-16 and LF commonly increased the expression of Fas protein and promoted apoptosis of tumor cells. YH-16 and LF attacked respective group of tumor cells to diminish the volume of tumor. |
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