Serial observations on an orthotopic gastric cancer model constructed using improved implantation technique

AIM:To establish a gastric cancer nude-mouse model with improved orthotopic implantation and investigate its biological characteristics at different time points.METHODS:Human gastric cancer SGC-7901 cell suspensions were injected subcutaneously into a nude mouse to develop solid tumors,and the tumor tissue pieces were implanted under the serous coat.The nude mice were then euthanized in group every two weeks to observe the primary tumor growth and metastases.RESULTS:Within 2-4 wk,there were no obvious chang-es about the primary tumor in stomach.At the sixth week,the primary tumor began to grow fast,resulting in incrassation of the gastric wall and stenosis of the gastric cavity,and metastases into the liver and lymph nodes were detected.The tumor,which compressed the adjacent organs,gradually became bigger and bigger followed by stenosis or vanishment of the gastric cavity from 8 to 12 wk.There were massive metastases,and the rate of metastasis was 58%in lymph nodes,78%in liver,39%in kidney,and 81%in peritoneum or septum.CONCLUSION:A gastric cancer model is established,which can simulate the clinical tumor behavior and provide experimental carrier for clinical trials of gastric cancer treatment.

Characterization of gastric cancer models from different cell lines orthotopically constructed using improved implantation techniques

AIM:To develop orthotopic gastric cancer mouse models from different cell lines and characterize the tumor features to assist further in preclinical trials and clinical treatment strategies.METHODS:Human gastric cancer SGC-7901 and BGC823 cell suspensions were injected subcutaneously into nude mice to develop solid tumors,and tumor tissue pieces were then implanted under the serous coat of the stomach.An autopsy was performed on all animals of the SGC-7901 and BGC-823 models to observe the primary tumor growth and metastases using pathological and immunohistochemical methods.RESULTS:Both models showed large tumors in situ resulting in pressure and infiltration of the adjacent organs.The gastric cavity became smaller,along with stenosis of the cardia or pylorus.There were biological and statistical differences between the two models.The metastasis rate in involved organs (lymph nodes,kidney,spleen,testis) was significantly higher in the BGC-823 model compared to the SGC-7901 model (P < 0.05 or P < 0.01).The median survival of the BGC-823 model was shorter than that of SGC-7901 (23 d vs 84 d,P < 0.05).Histopathologically,the primary tumor and metastatic lesions of the two models showed obvious atypia and mucus in the cytoplasm.Compared with the SGC-7901 model,BGC-823 appeared more poorly differentiated (absence of adenoid structure),had a smaller volume,and richer capillary structure.Immunohistochemical staining revealed cytokeratin 20 and epithelial membrane antigen expression was positive in the SGC-7901 tumors,while negative in BGC-823 ones.CONCLUSION:Models using the SGC-7901 and BGC-823 cell lines were established which could function in gastric cancer research on carcinogenesis mechanism and drug discovery.The two models showed different tumor behavior and the latter was more malignant than the former.

Establishment of orthotopic impact/metastasis model of human ovary cancer in nude mice

Objective: To establish a patient-like human ovary carcinoma /spontaneous metastasis model using orthotopic transplanation of histologically intact tumor tissue. Methods: An highly metastatic ovarian tumor line (HO-8910PM: Human serum carcinoma of the ovary )previously grown substaneously was transplanted into the ovicapsule using microsurgery technique .Histologically intact human ovary tumor pieces gained from implantation site were passaged between ovicapsules for four generations. Results: All mice developed ovary tumors and the metastatic rates were about 75%. The tumors only metastasized to liver but no other organs. The earliest appearance of metastasis was 14 d and the average survival period was 20.7±4.89 d.The microscopic appearance of the metastases was similar to the tumor observed in the substaneous xenografts and orthotopically transplanted. Chromosomes analysis exhibited the feature of human carcinoma and retained genetic stability during the processes of passage. Conclusion: Orthotopic implanation provides a suitable micro-enviroment in which ovarian cancer can express its intrinsic clinically-relevant properties. This approach is relevant to the spontaneous development of ovarian cancer and is thought to be a useful model for studies of metastatic mechanism and therapy for ovary cancer.

Knockdown of liver-intestine cadherin decreases BGC823 cell invasiveness and metastasis in vivo

AIM:To assess BGC823 gastric cancer(GC) cell metastasis after knockdown of liver-intestine cadherin(CDH17) and the therapeutic value of CDH17-RNAilentivirus in vivo.METHODS:We evaluated primary tumor growth and assessed local infiltration and systemic tumor dissemination using an orthotopic implantation technique.The therapeutic value of CDH17 knockdown was examined by intratumoral administration of CDH17-RNA interference(RNAi)-lentivirus in an established GC tumor xenograft mouse model.Furthermore,a comparative proteomic approach was utilized to identify differentially expressed proteins in BGC823 and lenti-CDH17-miRneg cells following CDH17 knockdown.RESULTS:Metastases in the liver and lung appeared earlier and more frequently in animals with tumors derived from BGC823 or lenti-CDH17-miR-neg cells than in tumors derived from lenti-CDH17-miR-B cells.Average tumor weight and volume in the CDH17-RNAi-lentivirus-treated group were significantly lower than those in the control group(tumor volume:0.89 ± 0.04 cm 3 vs 1.16 ± 0.06 cm 3,P < 0.05;tumor weight:1.15 ± 0.58 g vs 2.09 ± 0.08 g,P < 0.05).Fifteen differentially expressed proteins were identified after CDH17 silencing in BGC823 cells,including a variety of cytoskeletal and chaperone proteins as well as proteins involved in metabolism,immunity/defense,cell proliferation and differentiation,cell cycle,and signal transduction.CONCLUSION:Our data establish a foundation for future studies of the comprehensive protein expression patterns and effects of CDH17 in GC.

Orthotopic implantable liver decellularized scaffold for acute liver failure

Decellularized scaffolds have an irreplaceable role in the development of tissue engineering.Challenges in this field are concentrated on shaping macro-scale constructs and maintaining blood flow.Here,we establish a whole liver perfused decellularized scaffold cultured with hepatocytes for transplantable bioengineered liver construction.Owing to retained intact gross morphology of liver,geometric structure and biomechanical environment can support whole liver lobe transplantation.Besides,unremoved extracellular matrix(ECM)and vascular net-works can delivery continuous nutrient for cell adhesion.Based on recellularized bioengineering liver scaffold,we have demonstrated its excellent hepatic functions when it orthotopic implanted in acute liver failure(ALF)rats,along with the prolonged survival rate and improved biochemical indicators.These outstanding properties indicate that the orthotopic implantable liver scaffold has broad clinical application prospects in the treatment of ALF and other regeneration diseases.