| Docosahexaenoic acid (DHA) are omega-3polyunsaturated fatty acids (co-3PUFA), is one of the essential fatty acids of the human body. Have the role of Antithrombotic, lowering blood pressure, anti-atherogenic and inhibite excessive inflammation.in recent years,it is study found that the co-3PUFAs can inhibit a variety of tumor growth, invasion and metastasis, prolong the survival time of tumor-bearing hosts, but also can increase the effects of chemotherapy drugs and radiation therapy to inhibit tumor growth without increasing the toxicity of chemotherapy drugs. the patients with malignant tumors of the same time increase the in take of DHA and other co-3PUFA effectively slow tumor growth, inhibit tumor metastasis, and enable the already formed metastases disappeared.Gastric cancer is the most common gastrointestinal tumors, the incidence rate showed an increasing trend, surgery is still one of the main methods of treatment of gastric cancer. but after surgery and advanced cancer patients is often accompanied by malnutrition, immune dysfunction, cachexia,and other issues. DHA as a representative of co-3polyunsaturated fatty acid nutritional support is one of the measures to improve their nutritional status and immune function. but so far, DHA plus DDP on gastric cancer rarely reported, the combined mechanism is not very clear.In this study, DHA alone and combined with DDP, In vitro,Observe the impact of gastric cancer cell lines, In vivo,animal experiments further observed the inhibition of tumor-bearing nude mice. Explore the effects of the growth of gastric cancer cell lines, tumor-bearing nude mice, related genes of NF-kBp65survivin protein expression, to assess its role in the treatment of gastric cancer, and to evaluate its mechanism of actionof, Provide a theoretical basis and laboratory basis.for us to find a new ways of treatment of gastric cancer. Part I:Effects of Docosahexaenoic acid plus cisplatin on MGC-803cell of gastric cancer to inducing apoptosis and expressions of apoptosis-related geneObjective:To study the effects of Docosahexaenoic acid plus cisplatin on MGC-803cell of gastric cancer to inducing apoptosis and expressions of apoptosis-related gene, to analyze its possible mechanisms.Methods:MTT assay was performed to evaluate the repression effect of DHA combined with DDP on MGC803cells. And calculate the IC50values and Q values to determine the role of the two drugs. Morphous of cells was observed by inverted microscope. To observed apoptosis and morphology by DAPI, The cell cycle distribution and apoptosis rate were examined by flow cytometry. The expressions of survivin、NF-κB proteins were detected by immunohistochemical method.Results:The proliferation of MGC803cells was inhibited by DHA in a time-and dose-dependent manner (P<0.01). The IC50of CDDP48h and72h are4.31μg/mL and2.42μg/mL, and then decreased to2.12μg/mL and0.91μg/mL by combined DHA. Similarly, Q>0.85, The DHA could strengthen the cytotoxic effect of DDP on MGC803cells. Cells treated with DHA and DDP for48h became rarefaction under inverted microscope. after drug treatment which showed typical characteristics of apoptosis by using fluorescence microscopy. In the combination group, the number of cells in G0/G1phase was increased significantly (P<0.01), while which in G2/M phase and S phase was decreased significantly compared with the another group (P=0.01). The apoptosis rates were increased gradually in the control group, DHA group, DDP group and the combination group (P<0.01), The apoptosis rates of the combination group significantly up-regulated (P<0.01). Compared with the DDP alone and the DHA alone group, the expressions of survivin and NF-κB significantly down-regulated (P<0.05). Conclusion:The combination of DHA and DDP shows an enhanced ability to inhibit the proliferation of human gastric cancer cells MGC803and inducing apoptosis. This effect may be associated with the down-regulation of survivin, NF-κB expression.Part II:Inhibitory effects of Dococahexaenoic in combination with cisplatin on growth of gastric adenocarcinoma xenografts in nude miceObjective:To investigate the effects of DHA plus DDP human gastric cancer xenografts in vivo. We also wanted to demonstrate the relative mechanism of anticancer effects of DHA in combination with DDP on gastric cancer. To provide new ideas to the comprehensive treatment of gastric cancer.Methods:28nude armpit inoculated with0.2mL (1×106cells) human gastric cancer cells suspension. The model of nude mice bearing gastric xenografts tumor was established. They are randomly divided into four groups:(A) control group (Abdomen injection, Nacl,2times/w; gavage,1times/d);(B) DHA group (gavage,2g/kg,1times/d),(C) DDP group (Abdomen injection,3mg/kg,2times/w)、(D) DHA+DDP group (Abdomen injection,3mg/kg,2times/w; gavage, DHA,1times/d).2weeks of treatment, The Growth of rat and change of weight, as well as xenografts weight and volume change were recorded during course of experiment. The cell apoptosis rate were examined by FCM.The expressions of surviving、NF-κB proteins were detected by immunohistochemical method.Results:The tumor volume of each group:control group (3.25±0.25) cm3, DHA group (2.32±0.19) cm3, DDP group (1.00±0.08) cm3, DHA+DDP group (0.50±0.15) cm3. The tumor volume in nude mice of each drug-treated group was significantly smaller than that of the control group, the combination group was significantly smaller than DHA group and DDP group (P<0.01). The average weight of tumors in each treatment group have a significant difference Compared with the control group (P<0.01). Compared with the DDP alone and the DHA alone group, the weight of the combination group significantly down-regulated (P=0.001), respectively, The inhibition rate was84.66%,69.36%,28.62%. The anti-tumor efficacy of DHA plus DDP was significantly enhanced compared with DHA or DDP treatment alone (P<0.01). Loss of rat weight in DDP group was more serious than any group. DHA additive to DDP could help to protect weight loss. In each drug-treated group, The apoptosis rates were increased gradually from control group to the combination group, compared with the control group, DDP group and DHA group, The apoptosis rates of the combination group significantly up-regulated (P<0.01). Compared with the DDP alone and the DHA alone group, the expressions of the combination groups survivin and NF-κB significantly down-regulated (P<0.05).Conclusion:DHA was documented that it did not induce growth of xenografl, and DHA plus DDP would prohibit growth of tumor significantly. By comparision with DDP alone, DHA additive to DDP could protectbody weight in rat model. Possible mechanism was involved in apoptosis and the down-regulation of survivin, NF-κB expression induced by DHA plus DDP. |
PDF Full Text Request