Cytokinetic analysis of cell cycle and sub-phases in MOLT-4 cells by cyclin E + A/DNA multiparameter flow cytometry

Cell cycle analysis has become increasingly important in verifying the effect of anti-tumor drugs and cytokinetic research. In the early methods of cell cycle analysis, the flow cytometry relied on DNA content, and therefore, the cell cycle could be only broken into three stages: G(0)/G(1), S, and G(2)/M phase. It could not distinguish the G(0), G(1), G(2), and M phase cells, let alone the sub-phases in G(1) phase. In cell cycle, expression of cyclin E living up to the maximal level in the cells undergoing transition from G(1) to S phase, and G(2) + M cells are cyclin E negative. Expression of cyclin A is progressively increasing during S phase and is maximal in G(2) phase cells. Therefore, in the current study we established a cyclin E + A/DNA multiparameter flow cytometric technique by using a mixture of cyclin E and cyclin A antibodies, which can identify six stages in the whole cell cycle: G(0), early G(1), late G(1), S, G(2), and M phase. Furthermore, we found that cyclin E + A/DNA multiparameter flow cytometry could also be used for stathmokinetic analysis of lymphocyte leukemia MOLT-4 cells after addition of the stathmokinetic agent vinblastine to cultures of exponentially growing MOLT-4 cells. We believe that this new technique will provide a much better tool for molecular cell biology research and especially for cell proliferation kinetics investigations.