Leão Mariana, Soares Joana, Gomes Sara, Raimundo Liliana, Ramos Helena, Bessa Cláudia, Queiroz Glória, Domingos Sofia, Pinto Madalena, Inga Alberto, Cidade Honorina, Saraiva Lucília
UCIBIO/REQUIMTE, Laboratório de Microbiologia, Departamento de Ciências Biológicas, Laboratório de Farmacologia, Departamento de Ciências do Medicamento, Faculdade de Farmácia, Universidade do Porto, Rua de Jorge Viterbo Ferreira no. 164, 4050-313 Porto, Portugal.
Centro de Química Medicinal da Universidade do Porto (CEQUIMED-UP), Rua de Jorge Viterbo Ferreira no. 164, 4050-313 Porto, Portugal; Laboratório de Química Orgânica e Farmacêutica, Departamento de Ciências Químicas, Faculdade de Farmácia, Universidade do Porto, Rua de Jorge Viterbo Ferreira no. 164, 4050-313 Porto, Portugal; Centro Interdisciplinar de Investigação Marinha e Ambiental (CIIMAR/CIMAR), Universidade do Porto, Rua dos Bragas 289, 4050-123 Porto, Portugal.
Life Sci. 2015 Dec 1;142:60-5. doi: 10.1016/j.lfs.2015.10.015. Epub 2015 Oct 21.
Chalcones are naturally occurring compounds with recognized anticancer activity. It was recently shown that the O-prenyl derivative (2) of 2'-hydroxy-3,4,4',5,6'-pentamethoxychalcone (1) had a remarkably increased cytotoxicity against human tumour cells compared to its precursor. With this study, we aimed to investigate the molecular mechanism underlying the improved tumour cytotoxicity of prenylchalcone 2.
The impact of chalcones 1 and 2 on p53-MDM2 interaction was investigated using yeast growth-inhibitory and p53 transactivation assays. Their tumour growth-inhibitory effects were assessed on human colon adenocarcinoma HCT116 cell lines with wild-type p53 and its p53-null derivative, followed by analysis of cell cycle and apoptosis. In tumour cells, the activation of a mitochondrial pathway was checked by analysis of reactive oxygen species generation, Bax mitochondrial translocation and cytochrome c release. Additionally, the up-regulation of p53 transcriptional activity was investigated through Western blot analysis of p53 target expression levels, and the disruption of the p53-MDM2 interaction was confirmed by co-immunoprecipitation.
The potent cell tumour growth-inhibitory activity of prenylchalcone 2 was associated with the activation of a p53 pathway involving cell cycle arrest and a mitochondria-dependent apoptosis. Furthermore, a correlation between the distinct cytotoxicity of chalcones 1 and 2 and their ability to disrupt the p53-MDM2 interaction was established.
This work shows that prenylation is a determinant factor for the enhancement of chalcones tumour cytotoxicity by improving their ability to disrupt the p53-MDM2 interaction. Prenylchalcone 2 represents a starting basis for the design of new p53-MDM2 interaction inhibitors with improved antitumor properties.
查耳酮是具有公认抗癌活性的天然化合物。最近研究表明，2'-羟基-3,4,4',5,6'-五甲氧基查耳酮（1）的O-异戊烯基衍生物（2）与其前体相比，对人肿瘤细胞的细胞毒性显著增强。通过本研究，我们旨在探究异戊烯基查耳酮2增强肿瘤细胞毒性的分子机制。
使用酵母生长抑制和p53反式激活试验研究查耳酮1和2对p53-MDM2相互作用的影响。在具有野生型p53及其p53缺失衍生物的人结肠腺癌HCT116细胞系上评估它们的肿瘤生长抑制作用，随后分析细胞周期和细胞凋亡。在肿瘤细胞中，通过分析活性氧生成、Bax线粒体易位和细胞色素c释放来检测线粒体途径的激活。此外，通过对p53靶标表达水平的蛋白质印迹分析研究p53转录活性的上调，并通过免疫共沉淀证实p53-MDM2相互作用的破坏。
异戊烯基查耳酮2强大的细胞肿瘤生长抑制活性与涉及细胞周期阻滞和线粒体依赖性凋亡的p53途径激活有关。此外，还建立了查耳酮1和2的不同细胞毒性与其破坏p53-MDM2相互作用能力之间的相关性。
这项工作表明，异戊烯基化是通过提高查耳酮破坏p53-MDM2相互作用的能力来增强其肿瘤细胞毒性的决定性因素。异戊烯基查耳酮2代表了设计具有改进抗肿瘤特性的新型p53-MDM2相互作用抑制剂的起始基础。
