In vitro chemosensitivity of human lung cancer cell lines

Human lung cancer cell lines, established from patients with both small cell cancer (SCLC) and non-small cell cancer (non-SCLC; squamous cell, large cell, anaplastic, and adenocarcinoma), were tested for their in vitro chemosensitivity to a panel of drugs. Drug sensitivity was assayed by either soft agar clonogenicity or a novel dye-exclusion assay. Eleven non-SCLC lines (eight continuous, three recently cultured) and five SCLC lines (all continuous) were tested. Four of eight continuous non-SCLC lines cloned sufficiently to permit limited in vitro drug testing, as did two of the five SCLC lines. All 16 cell lines could be tested for multiple drugs using the dye-exclusion assay. Drug concentrations for the nonclonogenic assay more closely approximated the area under the concentration-time curve for a given concentration of each agent. There was considerable variation in the relative sensitivity of the cell lines and the patterns of individual drug sensitivity. The majority of non-SCLC cell lines were refractory to most drugs. Cell lines derived from two previously treated SCLC patients and from three untreated SCLC patients showed greater sensitivity. Concurrent clonogenic and dye-exclusion assays showed similar drug rankings but different absolute values for percent survival. The nonclonogenic dye-exclusion assay is more rapid than the soft agar clonogenic assay (4 days vs. 2-3 weeks), could be performed on all cell lines tested, and appears to reflect the clinical diversity of human lung cancer.