Kaempferide Enhances Chemosensitivity of Human Lung Adenocarcinoma A549 Cells Mediated by the Decrease in Phosphorylation of Akt and Claudin-2 Expression

Abstract

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.

Down-Regulation of Claudin-2 Expression by Cyanidin-3-Glucoside Enhances Sensitivity to Anticancer Drugs in the Spheroid of Human Lung Adenocarcinoma A549 Cells

“…The tight junctional localizations of CLDN1, CLDN2, and ZO-1 were examined by immunocytochemistry, as described previously [ 21 ].…”

“…Therefore, CLDN2 may be a novel target for the development of anticancer drugs. Some flavonoids, including kaempferol, luteolin [ 19 ], quercetin [ 20 ], and kaempferide [ 21 ], can reduce the expression level of CLDN2 in A549 cells. The transcriptional activity of CLDN2 is up-regulated by the phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt) and mitogen-activated protein kinase (MEK)/extracellular signal regulated kinase (ERK) pathways.…”

“…The transcriptional activity of CLDN2 is up-regulated by the phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt) and mitogen-activated protein kinase (MEK)/extracellular signal regulated kinase (ERK) pathways. Kaempferide increases the chemosensitivity of A549 cells to anticancer drugs, mediated by the suppression of the phosphorylation of Akt and CLDN2 expression [ 21 ]. However, the effects of C3G on the chemosensitivity and the CLDN2 protein in lung adenocarcinoma cells remain unclear.…”

Mechanism of Synsepalum dulcificum Daniell. Inhibiting Lung Adenocarcinoma

“…Furthermore, guanosine also has excellent antitumor activity and significant inhibitory activity on lung adenocarcinoma A5449 cell line [ 43 ]. Kaempferol and quercetin are the most widely studied antitumor substances; it has been reported that Kaempferol can reduce the expression of CLDN2 in A549 cells and further inhibit cell proliferation and migration [ 44 ]. It has been demonstrated that the anticancer activity of quercetin is facilitated via the activation of the adenosine monophosphate (AMP)-activated protein kinase (AMPK) pathway, suppression of the phosphoinositide 3-kinase/PI3K/AKT/mammalian target of rapamycin/NF- κ B pathway, upregulation of p53 activation, and the apoptosis pathway, and when used with other chemotherapeutic agents, quercetin can achieve tumor-improving results by enhancing apoptosis and reducing side effects [ 45 ].…”

Identifying Active Compounds and Mechanism of Camellia nitidissima Chi on Anti-Colon Cancer by Network Pharmacology and Experimental Validation

“…A total of 84 potential targets were obtained by taking the intersection. The majority of the compounds were flavonoids, such as quercetin, luteolin, kaempferide, and kaempferol, which have long been reported to have significant antitumor activity [ 33 – 36 ]. In this research, only eight compounds were found to meet the requirements of OB ≥30% and DL ≥ 0.18.…”