尽管已经确定大麻的主要非精神活性成分大麻二酚（CBD）具有抗肿瘤活性，但CBD杀伤肿瘤细胞的确切机制尚不清楚。本研究使用野生型（HCT116 p53wt，LS174T p53wt），基因敲除型（HCT116 p53-/-）和突变型（SW480 p53mut）人类结肠癌细胞（CRC），提供了CBD诱导的凋亡和自噬间相互对抗机制的新见解。CBD对p53wt细胞的存活能力损失比对p53-/-和p53mut细胞更为显著，而5周CBD治疗降低了小鼠体内HCT116 p53wt异种移植瘤的体积，但对HCT116 p53-/-肿瘤的体积无影响。在机制上，我们证明CBD只在携带野生型p53（HCT116，LS174T）的细胞中显著提高ROS生成，这与PARP1的积累有关。CBD诱导的ROS水平升高触发G0/G1细胞周期停滞，降低CDK2，激活p53依赖的caspase-8/9/3和自噬。自由基自噬可通过促进keap1/Nrf2通路的激活，可能受到p53wt的正调控，因为使用pifithrin-α抑制p53进一步减弱了CBD处理后的自噬。有趣的是，抑制热休克蛋白70（Hsp70）的表达显著增强p53wt细胞中caspase-3介导的程序性细胞死亡，而与核迁移Nrf2有关的自噬则被阻断。综上所述，我们的研究结果展示了CBD处理的结肠癌细胞中凋亡和自噬之间的错综复杂相互作用，其中受p53wt和Hsp70的复杂相互作用调节。© 2023年 死亡和分化（ADMC）

Although it has been established that cannabidiol (CBD), the major non-psychoactive constituent of cannabis, exerts antitumoral activities, the exact mechanism(s) via which tumor cells are killed by CBD are not well understood. This study provides new insights into the potential mechanisms of CBD-induced mutual antagonism of apoptosis and macroautophagy using wild type (HCT116 p53wt, LS174T p53wt), knockout (HCT116 p53-/-) and mutant (SW480 p53mut) human colorectal cancer cells (CRC). CBD causes a more pronounced loss in the viability of p53wt cells than p53-/- and p53mut cells, and a 5-week treatment with CBD reduced the volume of HCT116 p53wt xenografts in mice, but had no effect on the volume of HCT116 p53-/- tumors. Mechanistically, we demonstrate that CBD only significantly elevates ROS production in cells harboring wild-type p53 (HCT116, LS174T) and that this is associated with an accumulation of PARP1. CBD-induced elevated ROS levels trigger G0/G1 cell cycle arrest, a reduction in CDK2, a p53-dependent caspase-8/9/3 activation and macroautophagy in p53wt cells. The ROS-induced macroautophagy which promotes the activation of keap1/Nrf2 pathway might be positively regulated by p53wt, since inhibition of p53 by pifithrin-α further attenuates autophagy after CBD treatment. Interestingly, an inhibition of heat shock protein 70 (Hsp70) expression significantly enhances caspase-3 mediated programmed cell death in p53wt cells, whereas autophagy-which is associated with a nuclear translocation of Nrf2-was blocked. Taken together, our results demonstrate an intricate interplay between apoptosis and macroautophagy in CBD-treated colorectal cancer cells, which is regulated by the complex interactions of p53wt and Hsp70.© 2023. Cell Death Differentiation Association (ADMC).