| BACKGROUNDGastric cancer as one of the most common malignant tumors.Currently aim at gastric cancer,we use comprehensive treatment mainly including surgical resection combined with radiotherapy and chemotherapy and biological immunotherapy,but the overall efficacy and postoperative five-year survival rate is not ideal.As a new method of tumor therapy,targeted therapy has shown a certain superiority in the comprehensive treatment of tumor,and has been paid more and more attentionby academia.PI3K/AKT/mTOR is an important signaling pathway in the biological regulation of tumor cells.A number of studies have found that NVP-BEZ235 in a variety of tumor cells and animal models showed significant anti-tumor effect.But access to domestic and foreign literature about gastric cancer targeted therapy,we found little reports on the BEZ235.In this study,the effects of PI3K and mTOR dual target inhibitor NVP-BEZ235 alone or in combination with cytotoxic drug 5-FU on NCI-N87 xenografts in nude mice were studied to confirm the hypothetic conclusion from previous cell level experiments;and make sure the NVP-BEZ235 for gastric cancer cells have a certain anti-tumor effect to provide a reliable experimental basis.METHOD1.Stable human gastric cancer cell line NCI-N87 tumor-bearing mice were obtained by multiple in vivo passages.2.After the tumor volume was reached,the nude mice were randomly divided into four groups according to the body weight,and treated with normal saline、NVP-BEZ235,5-FU and NVP-BEZ235+5-FU respectively.Record the tumor volume and plot the tumor growth curve.3.After 30 days of drug intervention,nude mice were sacrificed,and the transplanted tumor was sacrificed.The tumor morphology was observed by HE staining.4.The expression of PI3K/Akt/mTOR signaling pathway and invasion-related protein was detected by Western Blot.RESULT1.With the increase of the number of passages,the tumor formation rate and the growth rate of the transplanted tumor were obviously improved,and the tumor growth rate was relatively stable.Transplanted tumors’border are clear,slightly soft texture,can be moved,was spherical bulging on skin,and the size of them is different.After drug intervention tumor growth was significantly limited,while the normal saline group until the end of the experiment,the tumor continued to increase and appeared huge multi-leaf.Tumor-bearing mice appeared reduced activity,loss of appetite,body weight loss and other cachexia performances.2.HE staining for removed transplanted tumor,in visual field visible diffuse distribution of heterogeneous cells with mitosis increased,deep staining,And in the central of tissues are large areas of necrosis.However,the characteristics of gastric adenocarcinoma are rare,and the boundry among interstitial cells and parenchymal cells unclear.3.The growth curve of NVP-BEZ235 + 5-FU group was significantly higher than that of the other three groups.The volume of the final tumor volume 5-FU group,BEZ235 group and combination group were smaller than those of the control group,but the difference was statistically significant(P<0.05).4.In the control group,12 nude mice died and survived 10,of which 5FU + BEZ235 combined with the treatment group died and survived 5,the remaining groups nude mice are all survived.(P<0.05);BEZ235 group showed a certain tumor inhibition,but there was no significant difference compared with NS group(P>0.05).The inhibitory effect of 5-FU + BEZ235 group was significantly higher than that of other groups(P<0.05).The tumor weight of 5-FU group and 5-FU + BEZ235 group was lighter than that of NS group(P<0.05).There was no significant difference between BEZ235 group and NS group(P>0.05)+ BEZ235 group had no significant difference compared with 5-FU group(P>0.05).5.As for PTEN,compared with the control group,there was no significant difference between the experiments groups and control group(P>0.05).The expression of p-Akt/Akt and mTOR in the 5-FU group was not statistically significant(P>0.05).In the combination group,the expression of p-Akt/Akt and mTOR were significantly lower than those in the control group and single-medicine groups(P<0.05).The expression of Bax/Bcl-2 and caspase3 in the 5-FU group was significantly higher than that in the control group(P<0.05),and the difference was statistically significant(P<0.05).Compared with the control group,the levels of Bax/Bcl-2 and caspase3 in the combination group were significantly higher than those in the control group.5-FU group and BEZ235 group(P<0.05).The expression of VEGF in the experiments groups was significantly lower than control group,and combination group was lower than that in the 5-FU and BEZ235 groups(P<0.05).CONCLUSION1.The anti-tumor effect by BEZ235 alone is limited,but the combination of BEZ235 and 5-FU can significantly improve the 5-FU anti-tumor effect.2.BEZ235 has a strong inhibitory effect on PI3K pathway protein.5-FU has no obvious inhibitory effect on PI3K pathway protein,but could be significantly improved by BEZ235.3.BEZ235 could enhance the proapoptotic effect of 5-FU.4.The expression of VEGF and MMP9 was significantly inhibited by BEZ235,and the inhibitory effect was more obvious by the combination of BEZ235 and 5-FU.5.The anti-tumor effect of BEZ235 depends on its inhibition of tumor cell growth and proliferation rather than directly kill tumor cells... |
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