Expression profiling of sodium butyrate (NaB)-treated cells: identification of regulation of genes related to cytokine signaling and cancer metastasis by NaB

Abstract

Histone deacetylase (HDAC) inhibitors induce growth arrest and apoptosis in a variety of human cancer cells. Sodium butyrate (NaB), a short chain fatty acid, is a HDAC inhibitor and is produced in the colonic lumen as a consequence of microbial degradation of dietary fibers. In order to dissect out the mechanism of NaB-induced growth inhibition of cancer cells, we carried out expression profiling of a human lung carcinoma cell line (H460) treated with NaB using a cDNA microarray. Of the total 1728 genes analysed, there were 32 genes with a mean expression value of 2.0-fold and higher and 66 genes with a mean expression value 3.0-fold and lower in NaBtreated cells. For a few selected genes, we demonstrate that their expression pattern by semiquantitative reverse transcription-polymerase chain reaction (RT-PCR) analysis is matching with the results obtained by microarray analysis. Closer view at the expression profile of NaBtreated cells revealed the downregulation of a total of 16 genes associated with cytokine signaling, in particular, interferon c (IFNc) pathway. In good correlation, NaBpretreated cells failed to induce interferon regulatory factor 1, an INFc target gene, efficiently upon IFNc addition. These results suggest that NaB inhibits proinflammatory cytokine signaling pathway, thus providing proof of mechanism for its anti-inflammatory activity. We also found that NaB induced three genes, which are known metastatic suppressors, and downregulated 11 genes, which have been shown to promote metastasis. Upregulation of metastatic suppressor Kangai 1 (KAI1) by NaB in a time-dependent manner was confirmed by RT-PCR analysis. The differential regulation of metastasis-associated genes by NaB provides explanation for the antiinvasive properties of NaB. Therefore, our study presents new evidence for pathways regulated by NaB, thus providing evidence for the mechanism behind antiinflammatory and antimetastatic activities of NaB.

Possible mechanism for the regulation of glucose on proliferation, inhibition and apoptosis of colon cancer cells induced by sodium butyrate

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Role of p53 status in chemosensitivity determination of cancer cells against histone deacetylase inhibitor sodium butyrate

“…37 1.5 x 10 3 cells per well were plated in a 96-well plate. After 24 hr of plating, the cells were treated with indicated amounts of NaB.…”

“…RT-PCR was carried out using a 2-step strategy: 37 cDNA was generated using Reverse Transcription kit (Promega, Madison, WI) in the first step and then using gene specific primer sets, PCR was carried out with cDNA as templates. GAPDH (Glyceraldehyde-3-phosphate dehydrogenase) is used for normalization.…”

Pharmaco-epigenomics: discovering therapeutic approaches and biomarkers for cancer therapy

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