Modulating activity of indomethacin to vincristine cytotoxicity in varioushuman carcinoma cells

The modulation activity of indomethacin to vincristine (VCR) was investigat ed in thirty human pulmonary carcinoma cell lines (adenocarcinoma 9, large cell carcinoma 9, squamous cell carcinoma 6, small cell carcinoma 6) and fi ve other cell lines (colon carcinoma 2, melanoma 1, teratocarcinoma 1, thym oma 1). The survival of these cell lines treated with VOR with or without i ndomethacin (2 mu g/ml) for 72 hours were examined using MTT assay, and IC5 0 values were calculated. When the cutoff level of potent combined effect i n clinical use was set at a-fold increase of sensitivity, the positive rate was 100% for adenocarcinomas and large cell carcinomas, 25% for squamous c ell carcinomas, 33% for small cell carcinomas. Mean modulating index was 2. 91 in adenocarcinomas, 1.92 in squamous cell carcinomas, 3.06 in large cell carcinomas and 1.67 in small cell carcinomas. Of the cell lines of other t umors, three cell lines (colon carcinoma i, melanoma 1, teratocarcinoma 1) showed the potent combined effect of VCR and indomethacin, while indomethac in was not effective in modulating activity to VCR in a thymoma cell line a nd fibroblast cells. In conclusion, it is considered that modulating activi ty of indomethacin for VCR is a general effect for various human cancer cel ls, and combined use with VCR and indomethacin may be a useful modulation t herapy for the advanced lung cancer. (C) 1998 Tohoku University Medical Pre ss.