Importance of orthotopic implantation for human tumors as model systems: relevance to metastasis and invasion
ABSTRACT Transplantation of human tumors into immunodeficient athymic nude mice has become an important experimental approach to study the biology and the treatment of human cancer. Most human tumor xenograft experiments have employed subcutaneous injection procedures, but the main limit of this technique is the lack of metastasis from the subcutaneous site. The possibility of producing experimental metastasis by intravenous injection of cells in the animals has been known for a long time, and it has been recently reported that tumorigenic properties and metastatic ability of human cancer can be altered by transplantation of the tumor into its organ or tissue of origin in the recipient animals (orthotopic transplantation). In this paper we review (1) the principal techniques of orthotopic injection of most solid tumors, (2) the most recent techniques to achieve experimental metastases, and (3) the methods for preparing tumor cell suspensions from human surgical specimens suitable for transplantation into animals. These animal models should be used for a more appropriate evaluation of new antitumor treatments including the ones targeted to inhibit metastatic spread.
- SourceAvailable from: Kazuaki Takabe[Show abstract] [Hide abstract]
ABSTRACT: TWO MOST COMMONLY USED ANIMAL MODELS FOR STUDYING BREAST CANCER LUNG METASTASIS ARE: lung metastasis after orthotopic implantation of cells into the mammary gland, and lung implantations produced after tail vein (TV) injection of cells. Tail vein injection can produce lung lesions faster, but little has been studied regarding the differences between these tumors, thus, we examined their morphology and gene expression profiles. Syngeneic murine mammary adenocarcinoma, 4T1-luc2 cells, were implanted either subcutaneously (Sq), orthotopically (OS), or injected via TV in Balb/c mice. Genome-wide microarray analyses of cultured 4T1 cells, Sq tumor, OS tumor, lung metastases after OS (LMet), and lung tumors after TV (TVt) were performed 10 days after implantation. Bioluminescence analysis demonstrated different morphology of metastases between LMet and TVt, confirmed by histology. Gene expression profile of cells were significantly different from tumors, OS, Sq, TVt or LMet (10,350 probe sets; FDR≤1%; P<0.0001). Sq tumors were significantly different than OS tumors (700 probe sets; FDR≤15%; P<0.01), and both tumor types (Sq and OS) were significantly different than LMet (1,247 probe sets; >1.5-fold-change; P<0.01), with no significant difference between TVt and LMet. There were significant differences between the gene profiles of cells in culture and OS versus LMet, but there were no differences between LMet versus TVt. Therefore, the lung tumor generated by TVt can be considered genetically similar to those produced after OS, and thus TVt is a relevant model for breast cancer lung metastasis.Journal of thoracic disease. 08/2013; 5(4):385-92.
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ABSTRACT: Molecularly targeted agents promise to revolutionize therapeutics by reducing morbidity and mortality in patients with cancer. However, despite an urgent need for more effective anticancer compounds, current preclinical drug evaluations largely fail to satisfy the demand. New preclinical strategies, including the improvement of sophisticated mouse models and co-clinical study designs, are being used to augment the predictive value of animal-based translational cancer research. Here, we review the development of successful preclinical antineoplastic agents, their associated limitations, and alternative methods to predict clinical outcomes.The Journal of clinical investigation 09/2013; 123(9):3639-45. · 15.39 Impact Factor
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ABSTRACT: This study used different methods to establish an animal model of orthotopic transplantation for ovarian cancer to provide an accurate simulation of the mechanism by which tumor occurs and develops in the human body. We implanted 4T1 breast cancer cells stably-transfected with luciferase into BALB/c mice by using three types of orthotopic transplantation methodologies: (1) cultured cells were directly injected into the mouse ovary; (2) cell suspension was initially implanted under the skin of the mouse neck; after tumor mass formed, the tumor was removed and ground into cell suspension, which was then injected into the mouse ovary; and (3) a subcutaneous tumor mass was first generated, removed, and cut into small pieces, which were directly implanted into the mouse ovary. After these models were established, in vivo luminescence imaging was performed. Results and data were compared among groups. Orthotopic transplantation model established with subcutaneous tumor piece implantation showed a better simulation of tumor development and invasion in mice. This model also displayed negligible response to artificial factors. This study successfully established an orthotopic transplantation model of ovarian cancer with high rates of tumor formation and metastasis by using subcutaneous tumor pieces. This study also provided a methodological basis for future establishment of an animal model of ovarian cancer in humans.Frontiers of medicine. 01/2014;