[Study of in vitro cancer sensitivity of anticancer drugs by SDI (succinate dehydrogenase inhibition test)].

To clarify the effect of fibroblast mixture in in vitro sensitivity test using SDI method. I have investigated the influence of fibroblast on the anticancer sensitivity test in a colon cancer cell line. The anticancer drugs, such as MMC (mitomycin C), CDDP (cisplatin) and 5-FU (5-fluorouracil) were contacted with colon cancer cells at 8 different concentrations on the intervals from 24 to 168 hours. The drug sensitivity of cancer cells in mixture of fibroblast was influenced by the kind of anticancer drugs, sensitivity of fibroblast itself, and the difference of sensitivity of cancer cell and fibroblasts. With the increase of percentage of fibroblast, the sensitivity of cancer cells became almost equivalent to that of fibroblast in 5-FU. But the sensitivity was not influenced by MMC or CDDP. And the difference of sensitivity was within about 27% by using 5-FU when the cancer cell ratio is 50%. Drug sensitivity of cancer cells was greatly influenced by drug concentration and contact time. Although the optimal contact time of sensitivity test depended on the kinds of drugs, 72 hours was considered to be optimal.