Chemosensitivity test for human small cell lung cancer cell lines in vitro

The in vitro response to seven chemotherapeutic drugs of three established human small cell lung cancer (SCLC) cell lines (NCI H69, H128, N231) was tested by a double soft agar clonogenic assay. Colony formation by the three cell lines was universally reduced more than 50% by continuous exposure to peak plasma concentrations of all the drugs. However by exposure to one-tenth of the peak plasma concentrations, the colony growth of H69 was reduced to 25.6% and 37.7% by etoposide and teniposide, respectively, and that of N231 was reduced to 46.7%, 39.0%, 27.5% by carboplatin, etoposide and teniposide, respectively. On the other hand colony formation by the three cell lines was not suppressed more than 50% by one-hour exposure to any of the drugs tested at one-tenth of the peak plasma concentrations. By one-hour exposure to drugs at the peak plasma concentrations, colony formation by H69, H128 and N231 was reduced more than 50% by cisplatin, etoposide, teniposide and nimustin, by adriamycin, teniposide and ACNU, and by adriamycin, etoposide, teniposide and nimustin, respectively. It was concluded that these three cell lines have similar sensitivity to seven drugs commonly used against small cell lung cancer.