Carcinogenesis
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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. ⋯ 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.