[Establishment and characterization of highly tumorigenic leukemia cell line HL-60 transplanted through repeated passages into nude mice].

This study was purposed to investigate the change of biological characteristics of HL-60 cells with high tumorigenicity transplanted through repeated passages into nude mice and to explore the tumorigenic mechanisms of the cell line. The human highly tumorigenic leukemia cell line HL-60 model in nude mice were established by serial passages in vivo and in vitro, and their biological features were compared. The trypan blue staining assay was used to detect the cell growth, the flow cytometry was used to analyze the cell cycle, the transmission electron microscopy and laser scanning confocal microscopy were used to observe the cell ultrastructures and cell fluorescence level respectively. The results indicated that the cell growth velocity was quickened, cell doubling time was shortened in high tumorigenic leukemia cell line HL-60; the cell count in S phase increased; the amount of mitochondria in HL-60 cells obviously decreased, furthermore the dilation of interspace, decrease of the number of ridges, vacuolation of mitochondria, significant reduction of fluorescence level in microfilament and enhancement of cell cloning efficacy were observed. It is concluded that the high tumorigenicity of HL-60 cells multiple-passaged in nude mice is associated with enhancement of proliferative ability, changes of number and structure of mitochondria in HL-60 cells, and alteration of microfilament in cytoskeleton.