Development of a Rapid Chemosensitivity Test for Anticancer Drugs With Contact-Sensitive Monolayer of Balb/3T3 Cells

Abstract

We investigated whether lethally irradiated, contact-sensitive Balb/3T3 cell confluent monolayers, termed “cell mats,” could be used for the screening of human tumors for sensitivity to anticancer drugs. Cell mats greatly inhibited the growth of normal Balb/3T3 cells and normal human flbroblasts but did not inhibit the growth of human tumor cells. To assess chemosensitivity of tumor cells, we measured the [¹⁴C]thymidine (dThd) incorporation by tumor cells that had been plated and then treated with various anticancer drugs on the cell mats. Although the [¹⁴C]dThd incorporation assay, when compared with the colony-formation assay, underestimated the toxicity of certain drugs, the assays gave similar results with regard to the degree of colony inhibition and to the decrease in [¹⁴C]dThd incorporation when various anticancer drugs were used at the same concentration ranges. Therefore, the method we used for measuring the isotope uptake in the cell mats could also be used to test for tumor-specific chemosensitivity. Because our results from this assay on various human tumor cells, including those from primary human tumors, can be obtained within 5 days, we believe that the system is potentially useful for testing anticancer drugs against human tumors in vitro.