In vitro chemosensitivity testing of human neuroblastoma cell lines in soft agar: a tumor-specific drug screening model.

Tumor-specific screening of investigational anticancer drugs is a new approach to cytotoxic drug screening. A tumor-specific drug screening model has been designed using established human neuroblastoma cell lines. In vitro drug sensitivity was studied using a modification of the human tumor stem cell assay. Eleven cell lines were tested initially for colony formation in soft agar. Four cell lines formed only small cell clusters, while three cell lines formed colonies at a very low rate. The four remaining lines formed colonies with satisfactory efficiency. These cell lines were exposed to three concentrations each of cis-platinum, vincristine, doxorubicin, L-phenylalanine mustard, and ethidium chloride and suspended in soft agar. Colony formation was tabulated and sensitivities determined for each cell line. A heterogeneous pattern of in vitro sensitivity was observed. Limitations and pitfalls as well as potential advantages of using such a tumor-specific drug screening system are discussed.