Chemosensitivity Testing of Lung Cancer Cells Using the MTT Assay.

A simple colorimetic test, the MTT assay, has been adapted for chemosensitivity testing of a human lung adenocarcinoma cell line, A549, and 25 lung cancer specimens clinically obtained by radical surgery. Seven different chemotherapeutic agents [cisplatin (CDDP), carboplatin (CBDCA), mitomycin C (MMC), adriamycin (ADM), etoposide (VP-16), vindesine (VDS), and 7-ethyl-10-ydroxyl camptothecin (SN-38)] were tested. Minced tumor tissues were treated with collagenase/DNase in RPMI 1640 medium containing 10% fetal calf serum for 1 h at 37°C. These cells were plated in 96-well plates at 1.0×104 cells per well. The MIT assay was carried out following incubation of the cells with each antitumor agent for 72 h in humidified 5% CO2 atmosphere at 37°C. The drug concentrations were determined on the basis of theoretical peak plasma concentrations (PPC) proposed by Scheithauer et al. The growth inhibition rates and IC50 (the concentration of drug that caused 50% reduction in absorbance compared to baseline values) were used for evaluation of the chemosensitivity.The growth inhibition rates of A549 and lung cancer specimens to all drugs except VDS gradually increased in a drug concentration-dependent manner as well as in an exposure timedependent manner. The mean IC50 values of 25 lung cancer specimens were: MMC: 1.40±1.77 PPC, SN-38: 2.15±3.19 PPC, ADM: 2.49±2.76 PPC, VP-16: 3.17±1.15 PPC, CDDP: 5.26±3.29 PPC, and CBDCA: 5.35±2.27 PPC. Although IC50 values of clinical samples were highly variable, MMC and SN-38 showed a strong antitumor activity. Thus it was concluded that MMC and SN-38 might be useful chemotherapeutic agents for human lung cancer.