Tumstatin Transgenic Megakaryocyte Combined With Gemcitabine Inhibits The Growth Of Lung Adenocarcinoma Cancer Xenografts In Mice

Backgroud : Lung cancer is a common type of malignant tumor,commonly used in clinical treatment of chemotherapy,and chemotherapy-induced thrombocytopenia so far there is no good solution,the clinical trials of platelet transfusions found that there will be the risk of promoting tumor growth and metastasis.Platelets are natural carriers of cytokines and biomolecules.Platelets contain many angiogenesis regulators,and their overall function is to promote angiogenesis.Platelet target clear,that is,the site of injury or proliferative cells with high density of sites such as vascular injury and tumorigenesis,platelets in the tumor microenvironment activation and release of active molecules play a role.The use of the tumstatin gene to modify platelet precursors results in the production of platelets that can inhibit neovascularization.This "designed platelet" releases tumstatin in the tumor microenvironment and may be imported during chemotherapy of the tumor To solve the problem of chemotherapy-induced thrombocytopenia and chemotherapy drugs to play together anti-tumor effect.In this study,lentivirus-transduced CD34 + cells carrying the tumstatin gene were cultured in vitro to produce anti-angiogenic megakaryocytes / platelets and venous injections via the tail vein of NOD / SCID mice resulted in inhibition of angiogenesis and maintenance of normal platelets On the basis of the study on the aggregation function of A549 cell lung adenocarcinoma xenografts in nude mice,the effect of tumstatin transgenic megakaryocytes and chemotherapeutic agent gemcitabine on A549 lung adenocarcinoma xenografts was studied.Objective: To investigate the feasibility and efficacy of tumstatin genetically modified megakaryocyte combined with chemotherapeutic agent gemcitabine in the treatment of A549 lung adenocarcinoma xenografts.,Provide basis for genetically modified platelet combined with chemotherapy for solid tumors.To observe the effect of tumstatin gene-modified megakaryocyte combined with gemcitabine on the growth,angiogenesis,tissue necrosis and apoptosis of lung adenocarcinoma mouse subcutaneous xenografts and the survival rate of tumor-bearing mice,and to explore the preliminary anti-tumor mechanism.Methods:(1)Preparation of tumstatin gene modified megakaryocytes;(2)Mouse lung adenocarcinoma xenograft model was established by inoculation of lung adenocarcinoma A549 cells in the back of NOD / SCID mice.The mice were randomly divided into 4 groups: saline control group,gemcitabine chemotherapy group,gemcitabine combined with megakaryocyte group,gemcitabine combination Tumstatin transgenic megakaryocyte group,the latter three groups for the treatment group;according to the group of mice were administered to each group for a total of 24 d,measured once every 3 d tumor volume.On the 15 th day of treatment,the orbital blood was collected and the blood cell count was detected by hematology analyzer.On the 24 th day,the subcutaneous neoplasm was dissected and weighed and the volume was measured.The microvessel density(MVD)of the subcutaneous neoplasm was counted by immunohistochemistry and HE staining,,Tissue necrosis,TUNEL method to measure the apoptosis of subcutaneous tumor tissue,record the survival of mice during treatment,and plot the survival curve of mice.Results:(1)The tumor volume growth curve of the treatment group was significantly slower than that of the saline group,of which the growth of transgenic megakaryocytes combined with chemotherapy group was the slowest;(2)The survival rate of the treatment group in the combination of genetically modified megakaryocytes and chemotherapy group was significantly improved than the chemotherapy alone group and the tumor growth inhibition was higher than the other three groups;(3)Compared with the other three groups,the MVD in the subcutaneous tumor of the transfected megakaryocyte and the chemotherapy group was significantly inhibited and caused the severe necrosis of the tumor tissue with the highest apoptosis index in the tumor tissue.Conclusion: The combination of tumstatin transgenic megakaryocytes and gemcitabine significantly inhibits the growth of transplanted lung adenocarcinoma A549 cells in mice and enhances the survival rate of tumor-bearing mice.This combined therapy of solid tumor methods is feasible.The initial mechanism is through inhibition of tumor angiogenesis and promote tumor cell necrosis and apoptosis.