In Vitro Vascularized Model For Tumor Growth And Progression

Introduction: Tumor metastasis is the primary reason for mortality of cancer patients. The ability to model the microenvironment of the primary tumor and the secondary and tertiary sites is critical for advancing the treatment options for the invasive cancers. There is currently no 3D tumor model that mimics the in vivo vascular geometry and the microenvironment for monitoring progression of tumors. In this study, we report on the development of a 3D tumor model comprising of vascular cells in communication with tumor cells leading to invasion and metastasis at secondary and tertiary sites. Materials and Methods: Vascularized tumor networks comprising primary, secondary and tertiary tumor sites were developed using in vivo images and fabricated using soft lithography. Human mammary microvascular endothelial cells (hMMEC) were cultured in the vascular channels while a GFP-labeled metastatic breast cancer cell (MDA-MB-231) and a GFP-labeled non-metastatic cell (MCF-7) mixed with and without human fibroblast cell line BJ-5ta was cultured in the primary tumor site in a 3D environment using Matrigel™. The tumor networks were perfused with endothelial cell media and the growth, migration, invasion and metastasis of the tumor cells from the primary site to secondary and tertiary site was monitored for 28 days using time lapse microscopy. Results and Discussion: The aggressively metastatic MDA-MB-231/BJ-5ta tumor at the primary site was found to proliferate rapidly resulting in breakdown of the Matrigel and invasion across the endothelial cells. Secondary sites were localized with pockets of tumor colonies within 48 hours and by 120 hours had metastasized to the tertiary site. By 14 days, the primary site tumor formed a necrotic core while the tumor cells at secondary and tertiary were viable. In contrast, the non-aggressive MCF-7/BJ-5ta tumors were able to proliferate within the Matrigel scaffolding but did not break down beyond the primary site until 14 days. Culture of tumor cells without the presence of fibroblast or endothelial cells resulted in a significant difference in the invasion and metastasis pattern highlighting the importance of the native tumor microenvironment. Conclusions: We have developed a 3D, heterogenic model of invasive tumor growth and metastasis which closely mimics the in vivo microenvironment of solid tumors. This model can be used to investigate tumor progression and their underlying mechanisms using a combination of real-time techniques as well as ‘omic’ methodologies for screening and evaluation of the therapeutics. Acknowledgements: We gratefully acknowledge financial support from NIH (#HHSN261201400037C). References: B. Prabhakarpandian et al., J Control Release 2015; 201:49-55 Citation Format: Ashley Smith, Charles Garson, Shantanu Pradhan, Elizabeth Lipke, Robert Arnold, Balabhaskar Prabhakarpandian, Kapil Pant. In vitro vascularized model for tumor growth and progression. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4108.