目的 观察蔓荆子总黄酮（Viticis Fructus total flavonoids，VFTF）抑制人小细胞肺癌NCI-H446细胞系肺癌干细胞（lung cancer stem cells，LCSCs）自我更新能力的作用。方法 体外培养NCI-H446细胞系细胞，免疫磁珠分选和干细胞条件培养基悬浮培养得到和扩增LCSCs；肿瘤球形成法检测自我更新能力，Western blotting分析自我更新相关转录因子Bmi1和磷酸化Akt（p-Akt）蛋白表达。结果 VFTF显著抑制LCSCs自我更新能力，呈浓度依赖性（P<0.05）；与亲本细胞比较，LCSCs细胞Bmi1和p-Akt蛋白表达水平增高；VFTF能有效下调LCSCs细胞Bmi1和p-Akt蛋白表达；PI3K特异性阻断剂LY294002增强VFTF抑制LCSCs自我更新能力的作用。结论 VFTF抑制源自NCI-H446细胞系LCSCs自我更新能力的作用与其下调p-Akt蛋白表达和抑制细胞自我更新相关转录因子Bmi1有关。

Objective To examine whether and how Viticis Fructus total flavonoids (VFTF) inhibit the capacity of self-renewal in lung cancer stem cells (LCSCs) derived from human small cell lung cancer NCI-H446 cell line. Methods NCI-H446 cell line was cultured in vitro. LCSCs were obtained and amplified by Magnetically activated cell sorting system (MACS) and suspended culture with serum-free conditioned medium. The capacity of self-renewal was detected by tumor sphere-forming assay. The protein expression levels of the self-renewal associated transcription factors, Bmi1 and p-Akt, were analyzed using Western blotting. Results VFTF significantly suppressed the capacity of self-renewal in LCSCs, in a concentration-dependent manner (P < 0.05). The expression levels of Bmi1 and p-Akt were elevated in LCSCs, compared with parental cells. VFTF effectively down-regulated the expression levels of Bmi1 and p-Akt in LCSCs. In addition, LY294002, a PI3K specific inhibitor, enhanced the inhibition of VFTF on the capacity of self-renewal in LCSCs. Conclusion VFTF could inhibit the self-renewal capacity of LCSCs derived from NCI-H446 cell line, which is associated with down-regulation of the expression of p-Akt and self-renewal associated transcription factors Bmi1.

湖南省研究生科研创新项目资助（Cx2013B225）；湖南省科技厅科技计划项目（2011FJ4144）