Abstract
The soft agar cloning assay has been successfully applied to suspension-grown mouse leukemia L 1210 (L 1210/V/C), L 5178 Y (L 5178 Y/C), and YOSHIDA ascites sarcoma (YAW) cells.
The effects of mitomycin C have been quantitatively studied on single cells of L 1210/V/C and YSA/ C cells under conditions such that almost 100% cells of L 1210/V/C and about 30% cells of YAS/C produce in isolation to form macroscopic colonies. Survival (5) of single cells (defined as the ability to form a macroscopic colony within 11 days) yields a typical exponential or single hit survival curve when plotted against mitomycin C concentration (D). The survival curve fits the following equation : log S= log n-kD. The reasons for exponential survival curve obtained by mitomycin C are discussed in comparison with the sigmoid, multi-hit survival curve observed in irradiation.
The sensitivity of cell to mitomycin C can be expressed by mean lethal dose, the reciprocal of slope coefficient k. On this basis, YAS/C cells is 100 times more sensitive to mitomycin C than L 1210/V/C cells.
