# Quercetin Decreases Claudin-2 Expression Mediated by Up-Regulation of microRNA miR-16 in Lung Adenocarcinoma A549 Cells **Authors:** Hiroyuki Sonoki, Tomonari Sato, Satoshi Endo, Toshiyuki Matsunaga, Masahiko Yamaguchi, Yasuhiro Yamazaki, Junko Sugatani, Akira Ikari PMC · DOI: 10.3390/nu7064578 · Nutrients · 2015-06-08 ## TL;DR Quercetin, a plant compound, reduces claudin-2 levels in lung cancer cells by boosting miR-16 and destabilizing claudin-2 mRNA. ## Contribution Quercetin's novel mechanism of decreasing claudin-2 via miR-16 up-regulation is identified in lung adenocarcinoma cells. ## Key findings - Quercetin decreases claudin-2 expression in a time- and concentration-dependent manner. - Quercetin increases miR-16 expression, which mediates the decrease in claudin-2. - Quercetin destabilizes claudin-2 mRNA, contributing to reduced expression. ## Abstract Claudin-2 is highly expressed in human lung adenocarcinoma tissues and cells. Knockdown of claudin-2 decreases cell proliferation and migration. Claudin-2 may be a novel target for lung adenocarcinoma. However, there are no physiologically active substances of foods which decrease claudin-2 expression. We here found that quercetin, a flavonoid present in fruits and vegetables, time- and concentration-dependently decreases claudin-2 expression in lung adenocarcinoma A549 cells. In the present study, we examined what regulatory mechanism is involved in the decrease in claudin-2 expression by quercetin. Claudin-2 expression was decreased by LY-294002, a phosphatidylinositol 3-kinase (PI3-K) inhibitor, and U0126, a MEK inhibitor. These drugs inhibited the phosphorylation of Akt and ERK1/2, which are downstream targets of PI3-K and MEK, respectively. In contrast, quercetin did not inhibit the phosphorylation. Both LY-294002 and U0126 inhibited promoter activity of claudin-2, but quercetin did not. The stability of claudin-2 mRNA was decreased by quercetin. Quercetin increased the expression of microRNA miR-16. An inhibitor of miR-16 rescued quercetin-induced decrease in the claudin-2 expression. These results suggest that quercetin decreases claudin-2 expression mediated by up-regulation of miR-16 expression and instability of claudin-2 mRNA in lung adenocarcinoma cells. ## Linked entities - **Genes:** CLDN2 (claudin 2) [NCBI Gene 9075], GDE1 (glycerophosphodiester phosphodiesterase 1) [NCBI Gene 51573], AKT1 (AKT serine/threonine kinase 1) [NCBI Gene 207], erk1/2 (mitogen-activated protein kinase) [NCBI Gene 778596] - **Proteins:** VPS34 (vacuolar protein sorting 34), MAP2K7 (mitogen-activated protein kinase kinase 7) - **Chemicals:** quercetin (PubChem CID 5280343), LY-294002 (PubChem CID 3973), U0126 (PubChem CID 3006531) - **Diseases:** lung adenocarcinoma (MONDO:0005061) ## Full-text entities - **Genes:** Cldn2 (claudin 2) [NCBI Gene 12738], BCL2 (BCL2 apoptosis regulator) [NCBI Gene 596] {aka Bcl-2, PPP1R50}, MCL1 (MCL1 apoptosis regulator, BCL2 family member) [NCBI Gene 4170] {aka BCL2L3, EAT, MCL1-ES, MCL1L, MCL1S, Mcl-1}, Mdk (midkine) [NCBI Gene 17242] {aka MK, Mek}, CLDN1 (claudin 1) [NCBI Gene 9076] {aka CLD1, ILVASC, SEMP1}, Cdx1 (caudal type homeobox 1) [NCBI Gene 12590] {aka Cdx, Cdx-1}, CLDN4 (claudin 4) [NCBI Gene 1364] {aka CPE-R, CPER, CPETR, CPETR1, WBSCR8, hCPE-R}, Egfr (epidermal growth factor receptor) [NCBI Gene 13649] {aka 9030024J15Rik, Erbb, Errb1, Errp, Wa5, wa-2}, GATA4 (GATA binding protein 4) [NCBI Gene 2626] {aka ASD2, TACHD, TOF, VSD1}, OCLN (occludin) [NCBI Gene 100506658] {aka BLCPMG, PPP1R115, PTORCH1}, CYCS (cytochrome c, somatic) [NCBI Gene 54205] {aka CYC, HCS, THC4}, SNAI2 (snail family transcriptional repressor 2) [NCBI Gene 6591] {aka SLUG, SLUGH, SLUGH1, SNAIL2, WS2D}, Cdx2 (caudal type homeobox 2) [NCBI Gene 12591] {aka Cdx-2}, DICER1 (dicer 1, ribonuclease III) [NCBI Gene 23405] {aka DCR1, Dicer, Dicer1e, GLOW, HERNA, K12H4.8-LIKE}, ERK1/2 [NCBI Gene 5595;5594], TNF (tumor necrosis factor) [NCBI Gene 7124] {aka DIF, IMD127, TNF-alpha, TNFA, TNFSF2, TNLG1F}, MIR155 (microRNA 155) [NCBI Gene 406947] {aka MIRN155, miRNA155, mir-155}, Gata4 (GATA binding protein 4) [NCBI Gene 14463] {aka Gata-4}, FOS (Fos proto-oncogene, AP-1 transcription factor subunit) [NCBI Gene 2353] {aka AP-1, C-FOS, p55}, Mapk1 (mitogen-activated protein kinase 1) [NCBI Gene 26413] {aka 9030612K14Rik, ERK, Erk2, MAPK2, PRKM2, Prkm1}, MIR198 (microRNA 198) [NCBI Gene 406975] {aka MIRN198, miR-198}, MAP2K7 (mitogen-activated protein kinase kinase 7) [NCBI Gene 5609] {aka JNKK2, MAPKK7, MEK, MEK 7, MKK7, PRKMK7}, Ccnd1 (cyclin D1) [NCBI Gene 12443] {aka CycD1, Cyl-1, PRAD1, bcl-1, cD1}, Hnf1a (HNF1 homeobox A) [NCBI Gene 21405] {aka HNF1, HNF1-alpha, HNF1[a], Hnf-1, Hnf1alpha, LFB1}, MAPK1 (mitogen-activated protein kinase 1) [NCBI Gene 5594] {aka ERK, ERK-2, ERK2, ERT1, MAPK2, NS13}, ELAVL1 (ELAV like RNA binding protein 1) [NCBI Gene 1994] {aka ELAV1, HUR, Hua, MelG}, CDX1 (caudal type homeobox 1) [NCBI Gene 1044], PIK3R1 (phosphoinositide-3-kinase regulatory subunit 1) [NCBI Gene 5295] {aka AGM7, GRB1, IMD36, p85, p85-ALPHA, p85alpha}, POTEF (POTE ankyrin domain family member F) [NCBI Gene 728378] {aka A26C1B, POTE2alpha, POTEACTIN}, STAT3 (signal transducer and activator of transcription 3) [NCBI Gene 6774] {aka ADMIO, ADMIO1, APRF, HIES}, Fos (Fos proto-oncogene, AP-1 transcription factor subunit) [NCBI Gene 14281] {aka D12Rfj1, c-fos, cFos}, AKT1 (AKT serine/threonine kinase 1) [NCBI Gene 207] {aka AKT, PKB, PKB-ALPHA, PRKBA, RAC, RAC-ALPHA}, MIR1303 (microRNA 1303) [NCBI Gene 100302284] {aka MIRN1303, hsa-mir-1303}, DROSHA (drosha ribonuclease III) [NCBI Gene 29102] {aka ETOHI2, HSA242976, RANSE3L, RN3, RNASE3L, RNASEN}, CLDN2 (claudin 2) [NCBI Gene 9075] {aka OAZON, claudin-2}, Stat3 (signal transducer and activator of transcription 3) [NCBI Gene 20848] {aka 1110034C02Rik, Aprf}, EGFR (epidermal growth factor receptor) [NCBI Gene 1956] {aka ERBB, ERBB1, ERRP, HER1, NISBD2, NNCIS}, CDX2 (caudal type homeobox 2) [NCBI Gene 1045] {aka CDX-3, CDX2/AS, CDX3}, DGCR8 (DGCR8 microprocessor complex subunit) [NCBI Gene 54487] {aka C22orf12, DGCRK6, Gy1, pasha}, GDE1 (glycerophosphodiester phosphodiesterase 1) [NCBI Gene 51573] {aka 363E6.2, MIR16}, CLDN18 (claudin 18) [NCBI Gene 51208] {aka SFTA5, SFTPJ} - **Diseases:** lung cancer (MESH:D008175), cancer (MESH:D009369), NSCLC (MESH:D002289), hepatocellular carcinoma (MESH:D006528), Alzheimer's disease (MESH:D000544), Lung Adenocarcinoma (MESH:D000077192), leukemic (MESH:D007938), glioma (MESH:D005910), colon cancer (MESH:D015179), colorectal and ovarian cancer (MESH:D010051), gastric cancer (MESH:D013274), inflammatory disease (MESH:D007249), adenocarcinomas (MESH:D000230), carcinogenesis (MESH:D063646), NS (MESH:D056770) - **Chemicals:** Cordycepin (MESH:C058120), actinomycin D (MESH:D003609), DMEM (-), PVDF (MESH:C024865), daidzein (MESH:C004742), SDS (MESH:D012967), penicillin-G potassium (MESH:D010400), Oligo (MESH:D009841), DMSO (MESH:D004121), Genistein (MESH:D019833), U0126 (MESH:C113580), CO2 (MESH:D002245), SYBR Green (MESH:C098022), Flavonoids (MESH:D005419), Lipofectamine 2000 (MESH:C086724), LY-294002 (MESH:C085911), poly (A) (MESH:D011061), streptomycin sulfate (MESH:D013307), agarose (MESH:D012685), Quercetin (MESH:D011794), lipopolysaccharide (MESH:D008070), dextran (MESH:D003911), cycloheximide (MESH:D003513), ethidium bromide (MESH:D004996), (MESH:D002867), (MESH:D009025), (MESH:D002070), (MESH:D009570) - **Species:** Homo sapiens (human, species) [taxon 9606], Mus musculus (house mouse, species) [taxon 10090] - **Cell lines:** S2 — Drosophila melanogaster (Fruit fly), Spontaneously immortalized cell line (CVCL_Z232), Caco-2 — Homo sapiens (Human), Colon adenocarcinoma, Cancer cell line (CVCL_0025), RAW264.7 — Mus musculus (Mouse), Mouse leukemia, Cancer cell line (CVCL_0493), HIEC-6 — Homo sapiens (Human), Finite cell line (CVCL_6C21), U-937 — Homo sapiens (Human), Adult acute monocytic leukemia, Cancer cell line (CVCL_0007), PC-3 — Homo sapiens (Human), Prostate carcinoma, Cancer cell line (CVCL_0035), ABC-1 — Homo sapiens (Human), Lung adenocarcinoma, Cancer cell line (CVCL_1066), A549 — Homo sapiens (Human), Lung adenocarcinoma, Cancer cell line (CVCL_0023), MDCK — Canis lupus familiaris (Dog), Spontaneously immortalized cell line (CVCL_0422) ## Full text _Full body text omitted from this summary view._ Fetch the complete paper as Markdown: https://tomesphere.com/paper/PMC4488803/full.md ## Figures 7 figures with captions in the complete paper: https://tomesphere.com/paper/PMC4488803/full.md ## References 48 references — full list in the complete paper: https://tomesphere.com/paper/PMC4488803/full.md --- Source: https://tomesphere.com/paper/PMC4488803