Kaempferide Enhances Chemosensitivity of Human Lung Adenocarcinoma A549 Cells Mediated by the Decrease in Phosphorylation of Akt and Claudin-2 Expression
Kaempferide Enhances Chemosensitivity of Human Lung Adenocarcinoma A549 Cells Mediated by the Decrease in Phosphorylation of Akt and Claudin-2 Expression
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DOI：
10.3390/nu12041190
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发表时间：
2020-04-01
期刊：
影响因子：
5.9
通讯作者：
Ikari, Akira
中科院分区：
文献类型：
--
作者：
Eguchi, Hiroaki;Matsunaga, Toshiyuki;Ikari, Akira
紧密连接蛋白（CLDN）在紧密连接的形成中发挥着至关重要的作用。我们报道了 CLDN2 的异常表达导致人肺腺癌 A549 细胞球体产生化疗耐药性。可以降低CLDN2表达的食物组合物可以起到预防恶性进展的作用。在这里，我们发现巴西绿蜂胶 (EBGP) 的乙醇提取物和 EBGP 的主要成分山奈素可降低 CLDN2 的表达。在二维培养模型中，EBGP 降低了 CLDN2 的紧密连接定位，而不影响衔接蛋白 zonula occlusionns-1 的紧密连接定位，并增强了细胞毒性抗癌药物阿霉素的细胞旁通透性。 EBGP减轻缺氧应激，增强A549细胞球体中阿霉素的积累和敏感性。尽管二氢山奈和松柏素不会降低 CLDN2 的表达，但山奈剂量依赖性地降低了 CLDN2 的表达。 Akt 的磷酸化是 CLDN2 表达的调节因子，可被山奈抑制，但不会被二氢山奈抑制。 C 环中的 2,3-双键对于抑制 Akt 可能很重要。 Kaempferide 降低 CLDN2 的 mRNA 水平和启动子活性，表明它抑制 CLDN2 的转录。根据 EBGP，山奈降低了 CLDN2 的紧密连接定位，并增加了阿霉素的细胞旁通透性，表明它减少了小分子的细胞旁屏障。此外，山奈素还可以减轻缺氧应激，增强球体中阿霉素的积累和敏感性。相反，二氢山柰醚没有提高对阿霉素的敏感性。需要使用动物模型进行进一步研究，但我们建议富含山奈的天然食品是预防肺腺癌化疗耐药的候选药物。
Claudins (CLDNs) play crucial roles in the formation of tight junctions. We have reported that abnormal expression of CLDN2 confers chemoresistance in the spheroids of human lung adenocarcinoma A549 cells. A food composition, which can reduce CLDN2 expression, may function to prevent the malignant progression. Here, we found that ethanol extract of Brazilian green propolis (EBGP) and kaempferide, a major component of EBGP, decrease CLDN2 expression. In the two-dimensional culture model, EBGP decreased the tight junctional localization of CLDN2 without affecting that of zonula occludens-1, an adaptor protein, and enhanced paracellular permeability to doxorubicin, a cytotoxic anticancer drug. EBGP reduced hypoxic stress, and enhanced the accumulation and sensitivity of doxorubicin in the spheroid of A549 cells. Kaempferide dose-dependently decreased CLDN2 expression, although dihydrokaempferide and pinocembrin did not. The phosphorylation of Akt, a regulatory factor of CLDN2 expression, was inhibited by kaempferide but not by dihydrokaempferide. The 2,3-double bond in the C ring may be important to inhibit Akt. Kaempferide decreased the mRNA level and promoter activity of CLDN2, indicating that it inhibits the transcription of CLDN2. In accordance with EBGP, kaempferide decreased the tight junctional localization of CLDN2 and increased a paracellular permeability to doxorubicin, suggesting that it diminished the paracellular barrier to small molecules. In addition, kaempferide reduced hypoxic stress, and enhanced the accumulation and sensitivity of doxorubicin in the spheroids. In contrast, dihydrokaempferide did not improve the sensitivity to doxorubicin. Further study is needed using an animal model, but we suggest that natural foods abundantly containing kaempferide are candidates for the prevention of the chemoresistance of lung adenocarcinoma.