Chair of Vegetative Anatomy, Institute of Anatomy, Faculty of Medicine, Ludwig-Maximilians-University Munich, Munich, Germany.
Institute of Anatomy and Cell Biology, Faculty of Medicine, University of Augsburg, Augsburg, Germany.
Front Immunol. 2023 Jul 27;14:1225530. doi: 10.3389/fimmu.2023.1225530. eCollection 2023.
P53 represents a key player in apoptosis-induction in cancers including colorectal cancer (CRC) that ranks third worldwide in cancer prevalence as well as mortality statistics. Although a pro-apoptotic effect of resveratrol has been repeatedly proven in CRC cells, its pathway mechanisms are not completely understood, as there are controversial statements in the literature regarding its activation or inhibition of the counteracting proteins Sirt-1 and p53.
CRC cells as wild-type (HCT-116 WT) or p53-deficient (HCT-116 p53) were cultured using multicellular tumor microenvironment (TME) cultures containing T-lymphocytes and fibroblasts to elucidate the role of p53/Sirt-1 modulation in resveratrol's concentration-dependent, pro-apoptotic, and thus anti-cancer effects.
Resveratrol dose-dependently inhibited viability, proliferation, plasticity as well as migration, and induced apoptosis in HCT-116 WT more effectively than in HCT-116 p53 cells. Moreover, resveratrol stimulated Sirt-1 expression when administered at low concentrations (<5µM) but suppressed it when added at high concentrations (>10µM) to CRC-TME. In parallel, similar to the knockdown of Sirt-1 at the mRNA level, treatment with high-concentration resveratrol boosted the acetylation of p53, the expression of p21, Bax, cytochrome C, caspase-3, and ultimately induced apoptosis in CRC WT but not in CRC p53 cells. Notably, increasing concentrations of resveratrol were found to promote hyperacetylation of p53 and FOXO3a as post-translational substrates of Sirt-1, indicating a negative regulatory loop between Sirt-1 and p53.
These results demonstrate for the first time, a negative reciprocal crosstalk between the regulatory circuits of p53 and Sirt-1, consequently, apoptosis induction by higher resveratrol concentrations in CRC-TME.
P53 是包括结直肠癌（CRC）在内的癌症细胞凋亡诱导的关键因子，CRC 在癌症发病率和死亡率统计中均位居世界第三。虽然白藜芦醇在 CRC 细胞中已被反复证明具有促凋亡作用，但由于文献中关于其对拮抗蛋白 Sirt-1 和 p53 的激活或抑制存在争议，其作用途径机制尚不完全清楚。
使用含有 T 淋巴细胞和成纤维细胞的多细胞肿瘤微环境（TME）培养物培养野生型（HCT-116 WT）或 p53 缺陷型（HCT-116 p53）CRC 细胞，以阐明 p53/Sirt-1 调节在白藜芦醇浓度依赖性、促凋亡、从而抗癌作用中的作用。
白藜芦醇剂量依赖性地抑制 HCT-116 WT 细胞的活力、增殖、可塑性和迁移，并比 HCT-116 p53 细胞更有效地诱导凋亡。此外，白藜芦醇在低浓度（<5µM）时刺激 Sirt-1 表达，但在高浓度（>10µM）时抑制其表达。同时，与 Sirt-1 在 mRNA 水平的敲低相似，高浓度白藜芦醇处理增强了 p53 的乙酰化、p21、Bax、细胞色素 C、caspase-3 的表达，并最终诱导 CRC WT 细胞凋亡，但不能诱导 CRC p53 细胞凋亡。值得注意的是，白藜芦醇浓度的增加被发现促进了 Sirt-1 的翻译后底物 p53 和 FOXO3a 的过度乙酰化，表明 Sirt-1 和 p53 之间存在负反馈调节环。
这些结果首次证明了 p53 和 Sirt-1 调节回路之间的负反馈相互作用，从而导致 CRC-TME 中较高浓度白藜芦醇诱导细胞凋亡。
