Comparison of antitumor activity of new anthracycline analogues, ME2303, KRN8602, and SM5887 using human lung cancer cell lines.

In an attempt to predict the clinical activity of newly developed anthracycline analogues, ME2303, KRN8602, and SM5887 in the treatment of lung cancer, we compared antitumor activity of these drugs with that of adriamycin, using six human lung cancer cell lines and two drug-resistant human lung cancer sublines. Taking the pharmacokinetic data into consideration, we evaluated the relative antitumor activity: the ratio of area under the concentration-time curve of each drug to the 50% inhibitory concentration of the drug. Regarding this ratio, ME2303 was more potent than adriamycin, SM5887, and KRN8602. Cross-resistance of the new analogues to adriamycin was investigated using an adriamycin-resistant small cell lung cancer subline, SBC-3/ADM100 and an etoposide-resistant subline, SBC-3/ETP. SBC-3/ADM100 being 106-fold more resistant to adriamycin than the parent SBC-3 showed less resistance to the analogues: 1.80-fold to KRN8602, 3.80-fold to SM5887, and 8.60-fold to ME2303. SBC-3/ETP which was 52.1-fold more resistant to etoposide and 39.5-fold more resistant to adriamycin were also less resistant to the new analogues: 3.27-fold to KRN8602, 9.07-fold to SM5887, and 17.3-fold to ME2303. In conclusion, ME2303 was found to be the most potent agent among drugs tested for the treatment of lung cancer, and KRN8602 can be expected to be beneficial for the treatment of drug-resistant small cell lung cancer.