title: Folate deprivation enhances invasiveness of human colon cancer cells mediated by activation of sonic hedgehog signaling through promoter hypomethylation and cross action with transcription nuclear factor-kappa B pathway.
abstract: Low folate status is well recognized as one of the metabolic stressors for colorectal cancer carcinogenesis, but its role in colon cancer invasion remains unknown. Activation of the Sonic hedgehog (Shh) signal in interaction with the transcription nuclear factor-kappa B (NF-κB) pathway is crucial for cancer aggressiveness. The aims of this study were to investigate whether and how folate deprivation promotes invasion by colon cancer cells in relation to Shh signaling and NF-κB pathway activation. Cultivation of epithelial colon carcinoma-derived cells (HCT116) in folate-deficient (FD) medium enhanced cellular migration and invasion, in correlation with epithelial-mesenchymal transition (EMT) associated with Snail expression and E-cadherin suppression, increased production of β1 integrin and increased proteolysis by matrix metalloproteinase 2. Blockade of Shh signaling by cyclopamine (CYC) or of NF-κB activation by BAY abolished FD-enhanced EMT and invasion by HCT116 cells. FD cells had 50-80% less intracellular folate, associated with aberrant hypomethylation of the Shh promoter, than control cells, and increased binding of nuclear NF-κB subunit p65 to the Shh promoter region, which coincided with increased Shh expression and protein production of Shh ligand; in addition, the FD-induced Shh signaling targeted Gli1 transcription activator as well as Ptch receptor. The FD-induced Shh induction and activated signaling were blocked by NF-κB inhibitor BAY. Blockade of Shh signaling abrogated FD-promoted NF-κB activation measured by IκBα degradation and by target gene TNFα expression. Taken together, these findings demonstrate that folate deprivation enhanced invasiveness of colon cancer cells mediated by activation of Shh signaling through promoter hypomethylation and cross actions with the NF-κB pathway.
authors.affiliation: Department of Nutritional Science, Fu Jen Catholic University, Xinzhuang, Taiwan, Republic of China.
authors.forename: Tz-Ping
authors.initials: TP
authors.lastname: Wang
authors.forename: Shu-Han
authors.initials: SH
authors.lastname: Hsu
authors.forename: Hsin-Chun
authors.initials: HC
authors.lastname: Feng
authors.forename: Rwei-Fen S
authors.initials: RF
authors.lastname: Huang
mesh_terms: D015820:Cadherins / Q000037:antagonists & inhibitors / Q000096:biosynthesis; D045744:Cell Line, Tumor; D002465:Cell Movement; D003110:Colonic Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D004247:DNA / Q000378:metabolism; D019175:DNA Methylation; D058750:Epithelial-Mesenchymal Transition; D005494:Folic Acid Deficiency; D015972:Gene Expression Regulation, Neoplastic; D053823:Hedgehog Proteins / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism*; D006801:Humans; D051550:I-kappa B Kinase / Q000378:metabolism; D019012:Integrin beta1 / Q000096:biosynthesis; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism; D016328:NF-kappa B / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D009361:Neoplasm Invasiveness; D009570:Nitriles / Q000494:pharmacology; D000072079:Patched Receptors; D000072081:Patched-1 Receptor; D011401:Promoter Regions, Genetic; D011956:Receptors, Cell Surface / Q000378:metabolism; D015398:Signal Transduction / Q000235:genetics; D000071250:Snail Family Transcription Factors; D013450:Sulfones / Q000494:pharmacology; D051996:Transcription Factor RelA / Q000378:metabolism; D014157:Transcription Factors / Q000096:biosynthesis; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis; D014704:Veratrum Alkaloids / Q000494:pharmacology; D000071676:Zinc Finger Protein GLI1
chemical_list: C434003:3-(4-methylphenylsulfonyl)-2-propenenitrile; D015820:Cadherins; C400551:GLI1 protein, human; D053823:Hedgehog Proteins; D019012:Integrin beta1; D016328:NF-kappa B; D009570:Nitriles; C000606236:PTCH1 protein, human; D000072079:Patched Receptors; D000072081:Patched-1 Receptor; D011956:Receptors, Cell Surface; C509239:SHH protein, human; D000071250:Snail Family Transcription Factors; D013450:Sulfones; D051996:Transcription Factor RelA; D014157:Transcription Factors; D014409:Tumor Necrosis Factor-alpha; D014704:Veratrum Alkaloids; D000071676:Zinc Finger Protein GLI1; D004247:DNA; D051550:I-kappa B Kinase; C522361:MMP2 protein, human; D020778:Matrix Metalloproteinase 2; C000541:cyclopamine