Cancer-on-a-Chip: Models for Studying Metastasis

Simple Summary Microfluidic-based cancer-on-a-chip models are powerful tools to study the tumor microenvironment (TME). Two-dimensional cell culture cannot recapitulate TME. In vivo animal models can better represent the TME, but their physiology is vastly different from that of humans. Although three-dimensional tumor models can bridge the gap between in vitro and in vivo examination, they are still unable to test many crucial cues from the TME, such as mechanical cues, cell-cell, and cell-extracellular interactions. Cancer-on-a-chip platforms enable studying the metastatic process in a step-wise manner with precise control. We present an overview of the recent advances in cancer-on-a-chip models on metastasis including models that mimic mechanical cues. This review article will provide knowledge of the latest progress made on cancer-on-a-chip models. The microfluidic-based cancer-on-a-chip models work as a powerful tool to study the tumor microenvironment and its role in metastasis. The models recapitulate and systematically simplify the in vitro tumor microenvironment. This enables the study of a metastatic process in unprecedented detail. This review examines the development of cancer-on-a-chip microfluidic platforms at the invasion/intravasation, extravasation, and angiogenesis steps over the last three years. The on-chip modeling of mechanical cues involved in the metastasis cascade are also discussed. Finally, the popular design of microfluidic chip models for each step are discussed along with the challenges and perspectives of cancer-on-a-chip models.