University of Coimbra, Institute for Interdisciplinary Research, Doctoral Programme in Experimental Biology and Biomedicine (PDBEB), Portugal; University of Coimbra, CNC-Center for Neuroscience and Cell Biology, Coimbra, Portugal; University of Coimbra, Coimbra Institute for Clinical and Biomedical Research (iCBR), Clinic Academic Center of Coimbra (CACC), Faculty of Medicine, Coimbra, Portugal; University of Coimbra, Center for Innovative Biomedicine and Biotechnology (CIBB), Coimbra, Portugal.
CBIOS-Universidade Lusófona's Research Center for Biosciences & Health Technologies, Lisbon, Portugal; Departamento de Ciencias Biomédicas, Facultad de Farmacia, Universidad de Alcalá de Henares, Madrid, Spain.
J Ethnopharmacol. 2024 Dec 5;335:118689. doi: 10.1016/j.jep.2024.118689. Epub 2024 Aug 14.
Glioblastoma (GB) is the most aggressive and prevalent glioma within the central nervous system. Despite considerable efforts, GB continues to exhibit a dismal 5-year survival rate (∼6%). This is largely attributed to unfavorable prognosis and lack of viable treatment options. Therefore, novel therapies centered around plant-derived compounds emerge as a compelling avenue to enhance patient survival and well-being. The South African species, Plectranthus hadiensis Schweinf. (P. hadiensis), a member of the Lamiaceae family, has a history of use in traditional medicine for treating a range of diseases, including respiratory, digestive, and liver disorders. This species exhibits diverse biological activities, such as anti-inflammatory and antitumoral properties, likely attributed to its rich composition of naturally occurring diterpenes, like the abietane diterpene, 7α-acetoxy-6β-hydroxyroyleanone (Roy). Roy has demonstrated promising antitumor effects in various cancer cell lines, making it a compelling candidate for further investigation into its mechanisms against GB.
This study aims to investigate the antitumor activity and potential mechanism of Roy, a natural lead compound, in GB cells.
Roy was isolated from the acetonic extract of P. hadiensis and its antitumor mechanism was assessed in a panel of human GB cell lines (U87, A172, H4, U373, and U118) to mimic tumor heterogeneity. Briefly, the impact of Roy treatment on the metabolic activity of cells was evaluated by Alamar Blue® assay, while cell death, cell cycle regulation, mitochondrial membrane potential, and activated caspase-3 activity were evaluated by flow cytometry. Measurement of mRNA levels of target genes was performed by qPCR, while protein expression was assessed by Western blotting. Cell uptake and impact on mitochondrial morphology were evaluated by confocal microscopy.
Roy induced G/M cell cycle arrest, mitochondrial fragmentation, and apoptosis by inhibiting the expression of anti-apoptotic proteins and increasing the levels of activated caspase-3. The concentrations of Roy needed to achieve significant inhibitory outcomes were notably lower (6-9 fold) than those of temozolomide (TMZ), the standard first-line treatment, for achieving comparable effects. In addition, at low concentrations (16 μM), Roy affected the metabolic activity of tumor cells while having no significant impact on non-tumoral cells (microglia and astrocytes).
Overall, Roy demonstrated a robust antitumor activity against GB cells offering a promising avenue for the development of novel chemotherapeutic approaches.
胶质母细胞瘤（GB）是中枢神经系统中最具侵袭性和最常见的神经胶质瘤。尽管已经付出了相当大的努力，但 GB 的 5 年生存率（约 6%）仍然不容乐观。这在很大程度上归因于预后不良和缺乏可行的治疗选择。因此，以植物衍生化合物为中心的新疗法成为提高患者生存率和生活质量的一个有吸引力的途径。南非物种 Plectranthus hadiensis Schweinf.（P. hadiensis），唇形科的一员，在传统医学中用于治疗一系列疾病的历史，包括呼吸道、消化和肝脏疾病。该物种表现出多种生物活性，如抗炎和抗肿瘤特性，这可能归因于其丰富的天然二萜类化合物组成，如 abietane 二萜类化合物 7α-乙酰氧基-6β-羟基罗内酯（Roy）。Roy 在各种癌细胞系中表现出有希望的抗肿瘤作用，使其成为进一步研究其对 GB 作用机制的有吸引力的候选物。
本研究旨在探讨 Roy 的抗肿瘤活性及其作为天然先导化合物在 GB 细胞中的潜在机制。
Roy 从 P. hadiensis 的丙酮提取物中分离出来，并在一组人类 GB 细胞系（U87、A172、H4、U373 和 U118）中评估其抗肿瘤机制，以模拟肿瘤异质性。简要地说，通过 Alamar Blue®测定评估 Roy 处理对细胞代谢活性的影响，通过流式细胞术评估细胞死亡、细胞周期调控、线粒体膜电位和激活的 caspase-3 活性。通过 qPCR 测定靶基因的 mRNA 水平，通过 Western blot 测定蛋白表达。通过共聚焦显微镜评估细胞摄取和对线粒体形态的影响。
Roy 通过抑制抗凋亡蛋白的表达和增加激活的 caspase-3 水平，诱导 G/M 细胞周期阻滞、线粒体碎片化和细胞凋亡。达到显著抑制效果所需的 Roy 浓度明显低于替莫唑胺（TMZ）的浓度（6-9 倍），TMZ 是标准的一线治疗药物，达到类似效果。此外，在低浓度（16 μM）下，Roy 影响肿瘤细胞的代谢活性，而对非肿瘤细胞（小胶质细胞和星形胶质细胞）没有显著影响。
总的来说，Roy 对 GB 细胞表现出强大的抗肿瘤活性，为开发新的化疗方法提供了一个有前途的途径。
