Three-Dimensional Scaffolds with Porous Membrane for Cell Separation and Migration Through Small Openings

Description

Cancer is the second leading cause of death. In 2018, nearly 18 million new cases and 10 million deaths are related to cancer globally. In Hong Kong, 30% of deaths are due to cancer and this is likely to increase as Hong Kong has an aging population and cancer incidence rate is found to increase rapidly with age. Ninety percent of solid tumor-related deaths are due to metastatic tumors – tumors that spread to a new, non-adjacent site by passing through tight junctions. When cells metastasize, they often remodel the extracellular matrix (ECM) surrounding the tumor cells and then migrate via the bloodstream. A tight junction occupies the intercellular space between adjacent endothelial cells, and it regulates what goes in and out of the blood vessels through the vascular endothelial cells. Invasive cancer cells can only gain access to the bloodstream by altering the structure of tight junctions and squeezing through.In order to study and target treatment to specific subpopulation of the tumor, it will be helpful to isolate cancer cells from normal cells as a single tumor site often contains a variety of cell types. We propose to develop microengineered, biomimetic three-dimensional (3D) platforms that can be used to separate cancer cells from normal cells based on their migration characteristics and to control how cells could migrate through small openings. Separating and studying how cancer cells could squeeze through small openings will lead to more accurately-targeted cancer treatment and potentially better control of tumor invasiveness.Microstructures in scaffolds play an important role in studying cancer cell migration and invasion in vitro as they mimic the 3D ECM and blood vessel in vivo. Multiple-layer scaffold platforms with designed dimension, topography, and stiffness will be developed to study cell migration of different cell types from one layer to another. Two cell lines including immortalized nasopharyngeal epithelial NP460 cells and carcinoma NPC43 cells will be used in this study. Nasopharyngeal carcinoma originates from the upper most region of the throat and it is a highly invasive and metastatic cancer that shows strong ethnic inheritance and geometrical distribution in Southeast Asia and southern China. Due to nonspecific symptom of NPC at early stage, most patients are diagnosed at the advanced stage which is difficult to treat. These 3D biomimetic platforms provide precisely controlled microenvironment to sort out NPC cells for early detection and treatments. While other reported results mainly focused on 2D dishes or 3D fibrous matrices, we propose to develop multiple-layer scaffold platforms with designed dimensions, layouts, stiffness, and protein coatings to selectively separate nasopharyngeal carcinoma NPC43 cells from epithelial NP460 cells. Being able to separate the carcinoma cells from the normal epithelial cells will potentially lead to a more effective drug delivery to targeted location and facilitate early treatment of NPC and other cancers.Platforms with small openings to mimic the epithelial porous interface and trenches below the porous membrane as blood vessels will also be developed. We plan to use a three-layer biomimetic model to mimic the ECM topography, the epithelial porous interface, and the underlying blood vessels as the microenvironment for cancer metastasis. By tracking cells traversing through the porous membrane and migrating in the trenches, we will be able to investigate the migration and invasion behaviors of different cells. Controlling factors that could influence cell traversing probability through small pores including pore size, pore shape, guiding topography design and orientation, and chemical coating will also be investigated. This biomimetic 3D vascular network has direct relevance for understanding and perhaps controlling cell invasion in tumor metastasis, which will provide insight for treatment of nasopharyngeal carcinoma or other cancers in the future.