Compared cytotoxicity effects of five anticancer drugs on human (HBL) and mouse (B16) melanoma cells in vitro.

In order to assess the potential interest of replacing the murine cell lines by human cell lines for in vitro cytotoxic assays, the sensitivity and the selectivity of the murine B16 and the human HBL melanomas to five chemotherapeutic drugs were investigated in vitro. The cytotoxicities of Melphalan, Daunorubicin (DNR), Hexamethylmelamine (HMM), Hydroxymethylpentamethylmelamine (HMPMM), and Dihydroxymethyltetramethylmelamine (DHTMM), 2 HMM derivatives, were measured in the two cell lines using two different techniques: reduction of a tetrazolium derivative (MTT) and tritiated thymidine uptake into DNA. The cytotoxicity at inhibitory concentration 50 (IC50) was determined after one hour as well as after 2 days exposure of cell after one hour as well as after 2 days exposure of cells to each drug. The results indicate that the HBL human melanoma was generally more sensitive to Melphalan and DHTMM than the B16 murine melanoma cells as far as the IC50 was concerned. In contrast, no difference of sensitivity was found to DNR and DHTMM. HMM was found to be inactive in both cell lines. The analysis of variance on IC50 values showed that the sensitivity of murine and human melanoma cell lines to drugs was statistically different. Despite the identical selectivity of the two cell lines, two promising observations can be made as far as the comparison of the two cell lines is concerned: 1) the higher sensitivity of HBL human cell line to Melphalan in the in vitro assays and 2) the slightly lower sensitivity of HBL to DNR, a drug without clinical activity against human melanoma.