Circulating Tumor Cell cultures (CTC) under pressure using Avatar bioreactor

The Avatar system from Xcell Biosciences was originally designed to maintain and propagate human stem cells under culturing conditions that replicate the stem cell niche. The system was modified to cultivate a variety of primary human tumor cells, including CTCs, by replicating conditions found within the tumor microenvironment. The Avatar system incorporates a unique bioreactor that regulates settings for oxygen and atmospheric pressure levels, in addition to the usual temperature and carbon dioxide controls. Complementing the novel bioreactor are serum-free, chemically defined culture media composed of recombinant human growth factors, and a CTC-capture substrate composedof a collagen-based hydrogel.

The workflow was developed in response to mounting evidence that hypoxia and pressure are influential traits in the cellular microenvironment that contribute to the maintenance and propagation of tumorcells. When complemented with an optimal cocktail of growth factors and a collagen-rich substrate found within tumor tissues, tumor cells can be maintained and propagated ex vivo, at rates similar to those observed in the body. Other studies investigatingcell morphology as well as gene and protein expression profiles have shown that cells cultured in the Avatar system more faithfully reflect in vivo biology than cells grown in traditional CO2 incubators supplemented with animal serum-based culture media.

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