细胞周期蛋白B1在肿瘤细胞中的非时相性表达

目的 证实细胞周期蛋白B1（cyclin B1）在体内和体外生长的肿瘤细胞中的非时相性周期表达模式,研究cyclin B1在不同生长状态和条件下的C1期肿瘤细胞中的表达情况。方法 以MOLT－4细胞为对照,应用流式细胞术的DNA/cyclin双参数分析法,检测体内和体外生长的肿瘤细胞中G1期cyclin B1的表达,对分选出的G1期细胞,以共聚焦显微镜观察G1期cyclin B1的表达;在不同体外生长情况下分选出G1期内亚细胞群体,以免疫印记法检测cyclin B1的表达。结果 在被阻滞生长的MOLT－4细胞、转化的T7细胞以及体内生长的肿瘤细胞中,均发现G1期有cyclin 的非时相性表达,被药物阻断生长的MOLT－4细胞中,cyclin B1主要表达于G1晚期;而转化的T7细胞中,cyclin B1主要表达于G1早期。结论 在研究的不同细胞模型中,G1期细胞有cyclin B1的非时相性表达,cyclin B1可以在G1期的不同时间点被检测到。这一现象可能与细胞的失控性增殖和细胞凋亡的调控之间有密切联系。

Unscheduled expression of cyclin B1 in G(1)-phase among cultured and clinical tumor cells

Objective To confirm the unscheduled in vivo and in vitro expression models of cyclin B1 in cancer cells so as to study the different profiles of cyclin B1 in G 1-phase immortal cells under different culture states and culture conditions. Methods Multiparameter flow cytometry (FCM) was used to correlate the expression of cyclin B1 with the position in cell cycle of immortal cells in vivo and in vitro using the MOLT-4 cell line as control. Cells which belonged to G 1-phase were sorted by FCM according DNA diploidy, and then the expression of cyclin B1 was examined by confocal microscope to confirm the results. For further analysis, different subgroups in G 1 phase were sorted according to the fluorescent intensity of cyclin E, and then the exact period in G 1 phase when cyclin B1 was expressed, were assayed by Western blot. Results Unscheduled expression of cyclin B1 expressed in G 1-phase was found not only in synchronized leukemia cells MOLT-4 and in vivo transformed T-7 cells, but also in vivo tumor cells detached from clinical samples. In the synchronized growing cells , cyclin B1 was mainly detected in the early G 1 phase, while in transformed T7 cells, cyclin B1 was mainly detected in the late G 1 phase. Conclusion The limitation of detecting cyclin B1 is due to its unscheduled expression , rending cyclin B1 being detected at different time-spots in the G 1 phase. This phenomenon may be related to the adjustment between the loss of control in cell proliferation and cell apoptosis, thereby leading to tumorigenesis.