Zhang Yin-Xu, Liu Xiao-Mei, Wang Jing, Li Jun, Liu Ying, Zhang Hua, Yu Xue-Wen, Wei Ning
a Liaoning Medical University; Jinzhou , PR China.
Cancer Biol Ther. 2015;16(6):965-75. doi: 10.1080/15384047.2015.1040950. Epub 2015 Apr 20.
PUMA (p53 unregulated modulator of apoptosis), a BH3-only Bcl-2 family member, can be induced by p53-dependent and p53-independent manners. It plays an important role as regulator of cellular apoptosis. Herein, we evaluate the effects of H1 (a derivative of tetrandrine) on induction of PUMA and underlie its potential mechanism in p53-independent cytotoxic response. Anti-proliferative activity and evidently cytotoxic activity of H1 were observed in wild-type and p53 null cells. Further studies demonstrated that H1 resulted in an increase of cleaved PARP, decease of survivin and elevation of p-H2AX. What is more, H1 significantly induced PUMA expression in a concentration- and time-dependent manner and caused an increase of Bax/Bcl-2 ratio in p53 null cells. Of note, knockdown of PUMA attenuated cytotoxic activity of H1. Further studies demonstrated that inhibition of AKT/FoxO3a signaling contributed to H1-mediated PUMA induction. Targeted suppression of AKT/FoxO3a signaling by siRNA could overcome H1-mediated PUMA induction. In addition, H1 significantly suppressed NF-κB activity and caused an increase of early apoptotic and late apoptotic cells, and elevated caspase-3 activity. Taken together, we found that inhibition of AKT/FoxO3a signaling may contribute to H1-mediated PUMA induction, suggesting that inhibition of AKT/FoxO3a signaling result in PUMA expression in response to p53-independent cytotoxic effects of H1.
PUMA（p53凋亡非调节性调节因子）是仅含BH3结构域的Bcl-2家族成员，可通过p53依赖性和p53非依赖性方式被诱导。它作为细胞凋亡的调节因子发挥重要作用。在此，我们评估汉防己甲素衍生物H1对PUMA诱导的影响，并探究其在p53非依赖性细胞毒性反应中的潜在机制。在野生型和p53缺失细胞中均观察到H1具有抗增殖活性和明显的细胞毒性活性。进一步研究表明，H1导致PARP裂解增加、存活素减少以及p-H2AX升高。此外，H1以浓度和时间依赖性方式显著诱导PUMA表达，并导致p53缺失细胞中Bax/Bcl-2比值增加。值得注意的是，敲低PUMA可减弱H1的细胞毒性活性。进一步研究表明，抑制AKT/FoxO3a信号通路有助于H1介导的PUMA诱导。通过siRNA靶向抑制AKT/FoxO3a信号通路可克服H1介导的PUMA诱导。此外，H1显著抑制NF-κB活性，导致早期凋亡和晚期凋亡细胞增加，并提高caspase-3活性。综上所述，我们发现抑制AKT/FoxO3a信号通路可能有助于H1介导的PUMA诱导，这表明抑制AKT/FoxO3a信号通路可导致PUMA表达，以响应H1的p53非依赖性细胞毒性作用。
