Chongqing Key Laboratory of Translational Research for Cancer Metastasis and Individualized Treatment, Chongqing University Cancer Hospital, Chongqing, 400030, China.
Key Laboratory for Biorheological Science and Technology of Ministry of Education (Chongqing University), Chongqing University Cancer Hospital, Chongqing, 400030, China.
BMC Complement Med Ther. 2022 Mar 23;22(1):85. doi: 10.1186/s12906-022-03568-3.
The leaves of the plant Ilex latifolia Thunb. can be made into Kuding tea, which is a drink rich in polyphenols. This study aimed to observe the effect of Ilex latifolia Thunb. polyphenols (ILTPs) on human lung cancer cell line A549 (A549 cells) by regulating the phosphatidylinositol 3-kinase/protein kinase B (PI3K/Akt) signaling pathway.
In vitro cultured cells were treated with ILTPs; the proliferation of A549 cells and BEAS-2B human normal lung epithelial cells (Beas-2B cells) was observed using the 3-(4,5-dimethylazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, and the survival status of A549 cells was observed by fluorescence staining. The expression of A549 cells was observed by quantitative polymerase chain reaction (qPCR) assay and Western blot analysis, while the compound composition of ILTPs was detected using high-performance liquid chromatography (HPLC).
The experimental results showed that the proliferation of Beas-2B cells was unaffected by treatment with 0-500 μg/mL of ILTPs, whereas the decreased proliferation of A549 cells was observed with the increasing concentrations of ILTPs. Additionally, ILTPs elevated the levels of lactate dehydrogenase (LDH) and reactive oxygen species (ROS) and promoted apoptosis in A549 cells. The results of qPCR experiments showed that ILTPs upregulated caspase-9 mRNA expression and downregulated phosphatidylinositol 3-kinase (PI3K), protein kinase B (Akt), mammalian target of rapamycin (mTOR), B-cell lymphoma-2 (Bcl-2), nuclear factor-κB (NF-κB), vascular endothelial growth factor (VEGF), hypoxia-inducible factor-1 alpha (HIF-1α), and cyclooxygenase-2 (COX-2) expression in A549 cells. The Western blot analysis results also showed that ILTPs could reduce the protein expression of PI3K and Akt. The HPLC results showed that the main compounds present in the ILTPs were rutin, kaempferol, isochlorogenic acid A, isochlorogenic acid B, and isochlorogenic acid C.
Thus, this study indicated that the polyphenols of I. latifolia act as a class of natural functional food materials that potently suppress cancer by exerting their inhibitory effects on A549 cell proliferation through five key polyphenolic compounds.
冬青科植物苦丁茶的叶子可制成苦丁茶，是一种富含多酚的饮料。本研究旨在通过调节磷脂酰肌醇 3-激酶/蛋白激酶 B（PI3K/Akt）信号通路观察冬青叶多酚（ILTPs）对人肺癌细胞系 A549（A549 细胞）的影响。
体外培养的细胞用 ILTPs 处理；通过 3-（4,5-二甲基噻唑-2-基）-2,5-二苯基四氮唑溴化物（MTT）测定法观察 A549 细胞和 BEAS-2B 人正常肺上皮细胞（Beas-2B 细胞）的增殖，并用荧光染色观察 A549 细胞的存活状态。通过定量聚合酶链反应（qPCR）检测和 Western blot 分析观察 A549 细胞的表达，并用高效液相色谱（HPLC）检测 ILTPs 的化合物组成。
实验结果表明，0-500μg/ml 的 ILTPs 处理对 Beas-2B 细胞的增殖没有影响，而随着 ILTPs 浓度的增加，A549 细胞的增殖减少。此外，ILTPs 升高了乳酸脱氢酶（LDH）和活性氧（ROS）的水平，并促进了 A549 细胞的凋亡。qPCR 实验结果表明，ILTPs 上调了 caspase-9mRNA 的表达，下调了磷脂酰肌醇 3-激酶（PI3K）、蛋白激酶 B（Akt）、雷帕霉素靶蛋白（mTOR）、B 细胞淋巴瘤-2（Bcl-2）、核因子-κB（NF-κB）、血管内皮生长因子（VEGF）、缺氧诱导因子-1α（HIF-1α）和环氧化酶-2（COX-2）在 A549 细胞中的表达。Western blot 分析结果还表明，ILTPs 可以降低 PI3K 和 Akt 的蛋白表达。HPLC 结果表明，ILTPs 中的主要化合物为芦丁、山奈酚、异绿原酸 A、异绿原酸 B 和异绿原酸 C。
因此，本研究表明，冬青叶中的多酚类物质作为一类天然功能性食品材料，通过 5 种关键多酚化合物对 A549 细胞增殖的抑制作用，强力抑制癌症。
