| Objective: To establish the metastasis model of gastric cancer derived from clinical tumor specimens,clarify its metastasis characteristics,preliminary screen metastasis-related genes of gastric cancer and analyze its function,thus to provide individualized preclinical models for studying the metastasis of gastric cancer.Methods: The patient-derived xenograft(PDX)model was established by subcutaneous transplantation of fresh clinical gastric cancer specimens into BALB/c nude mice.The tumor growth was monitored and the tumor volume was recorded dynamically.Furthermore,the tumor tissue from the PDX model was transplanted into the muscle layer of mouse stomach to establish the patient-derived orthotopic xenograft(PDOX)model,and the vital signs of the mice were continuously observed.The occurrence of gastric tumorigenesis and distant organ metastasis was detected by near infrared(NIR)fluorescence optical imaging in vivo.When the mice bearing tumor become weakness,they were dissected,and the lung metastatic lesion and the liver metastatic lesion were further subcutaneously transplanted into nude mice to form tumors.Both the primary tumor and metastatic tumor tissues were collected for Hematoxylin-eosin staining and STR typing analysis to confirm their morphological and genetic consistency with the patient’s primary tumor tissue.The expression of gastric cancer metastasis-associated genes in primary and metastatic tumors was detected by PCR Array analysis.The expression of metastasis-related genes in gastric cancer cell lines was also detected by RT-PCR and Western Blot.Base on the above results,we selected MMP2 gene for further research.The expression of MMP2 was silenced by siRNA transfection to evaluate the effect of MMP2 gene on the migration of gastric cancer cells.Results: Human gastric cancer PDX models were successfully established,and the consistency of the histopathological features between the transplanted tumor and the patient’s tumor was confirmed.Metastatic lesions in the lung and liver were found in the mouse No.C19751,C65175 and B97493 following orthotopic gastric transplantation.Tumor was formed after subcutaneous transplantation of lung metastasis lesion,and STR analysis showed that lung metastatic tumor maintained similar genetic characteristics to the primary tumor.The results of PCR Array and PT-PCR demonstrated that the expression of MMP2 was significantly up-regulated both in C19751 and B97493 metastatic tumor samples than the primary tumor.Compared with normal gastric epithelial cells GES-1,the expression of MMP2 mRNA and protein both in gastric cancer cells C61262 and MKN1 was significantly increased,the expression of EPHB2 and FXYD5 mRNA both in SGC-7901 and BGC-823 cell was significantly increased using RT-PCR and Western Blot analysis.Silencing the MMP2 gene both in gastric cancer cells MKN1 and C61262 significantly reduced the cell’s ability to migrate.Conclusions: Three PDX metastasis models of gastric cancer were successfully established in nude mice by transplantation clinical tumor specimens,all of which maintained the biological characteristics of the primary tumor.These models provided perfect individualized experimental tools for exploring gastric cancer metastasis mechanism.The genes of MMP2,FXYD5 and EPHB2 were screened successfully.When MMP2 gene was silenced,the migration ability of gastric cancer cells was significantly reduced. |
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