K252A - A NEW BLOCKER OF THE CELL-CYCLE AT G1 PHASE IN A HUMAN HEPATOMA-CELL LINE

The administration of 200 nM K252a to HuH7 suppressed the proliferation of the cells almost completely. The uptake of [H-3]thymidine was inhibited, and flow cytometry revealed only one peak at 2C on day 3 after treatment with 100 nM K252a. The expression of proto-oncogene c-myc was not reduced. Despite the blockage at GI, both the size of the cells and the amount of cell protein had increased by 4 times by day 3 after treatment with K252a, while the cells secreted albumin and alpha-fetoprotein into the medium as usual. These results show that K252a can increase the cell size of HuH7 without losing its function by blocking the cell cycle at G1 phase.