Breast cancer is a major health concern worldwide and is the leading cause of
cancer-related death among American women. Traditional
therapies, such as surgery,
chemotherapy, and
radiotherapy, are usually ineffective. Furthermore,
cancer recurrence following targeted
therapy often results from acquired drug resistance. Therefore, more realistic
tumor models than monolayer cell culture for
drug screening and discovery in an in vitro setting would facilitate the development of new therapeutic strategies. Toward this goal, we first developed a simple, rapid, low-cost, and high-throughput method for generating uniform multi-cellular
tumor spheroids (MCTS) with controllable size. Next, biomimetic
cryogel scaffolds fabricated from
hyaluronic acid (HA) were utilized as a platform to reconstruct
breast tumor microtissues with aspects of the complex tumor microenvironment in three dimensions. Finally, we investigated the interactions between the HA-based
cryogels and CD44-positive
breast tumor cells, individually or as MCTS. We found that incorporating the adhesive
RGD peptide in
cryogels led to the formation of a monolayer of
tumor cells on the
polymer walls, whereas MCTS cultured on RGD-free HA
cryogels resulted in the growth of large and dense microtumors, more similar to native
tumor masses. As a result, the MCTS-laden HA
cryogel system induced a highly aggressive and
chemotherapy drug-resistant
tumor model. RGD-free HA-based
cryogels represent an effective starting point for designing
tumor models for preclinical research, therapeutic
drug screening, and early
cancer diagnosis.