Perfusion culture using layered cell sheets with cancer cells and vascular endothelial cells

Article information
Vascularized Tissue-Engineered Model for Studying Drug Resistance in Neuroblastoma.
Villasante A, Sakaguchi K, Kim J, Cheung NK, Nakayama M, Parsa H, Okano T, Shimizu T, Vunjak-Novakovic G.
Theranostics 2017; 7(17):4099-4117.

Overview
Neuroblastoma, a cancer derived from undifferentiated neural crest cells, consists of a highly heterogeneous mixture of cancer cells, including a vascular structure. Some 30-50% of neuroblastomas are classified as high risk, a class typified by MYCN gene amplification, advanced stage, presence in patients over 12-18 months of age, malignant tissue type, etc.

Isotretinoin (INN) is a vitamin A derivative also known as 13-cis-retinoic acid. Because high-concentration INN exhibits antitumor effects in vitro, the compound has been used for treating minimal residual disease in high-risk neuroblastoma patients. However, a recent analysis indicated that administration of INN to paediatric patients with high-risk neuroblastoma has no effect on progression-free survival or overall survival.

To address this issue, the authors fabricated an in vitro model of neuroblastoma incorporating a vascular bed on a collagen gel containing a flow path for perfusion culture; three layers of neuroblastoma cells and a vascular endothelial cell sheet were mounted on the vascular bed, and the resulting model was used to study the mechanism of drug resistance to INN.

Vasculogenic mimicry by neuroblastoma cells (formation of blood vessel-like structure by cancer cells and transdifferentiation of cancer cells to tumour vascular endothelial cells) was observed after 4 days of perfusion culture. INN treatment decreased the number of MYCN-expressing neuroblastoma cells due to increased apoptosis; similar effects were not observed in tumour vascular endothelial cells.

The authors observed that INN treatment triggered a shift from a SOX2-low state to a SOX2-high state, inducing the proliferation of subpopulations of cancer stem cells expressing high levels of SOX2. These results suggested that SOX2 might serve as a new therapeutic target for neuroblastoma.