Effect of sodium butyrate in comparison with trichostatin a on p21waf1/cip1 gene expression in colon carcinoma.
,1,* Masumeh sanaei
1. Research center for non-communicable diseases, Jahrom University of medical sciences, Jahrom, Iran
2. Research center for non-communicable diseases, Jahrom University of medical sciences, Jahrom, Iran
Acetylation of histone is a fundamental molecular mechanism of transcriptional regulation which affects gene expression epigenetically. histone acetylation open the chromatin structure resulting in increased transcription. this acetylation is regulated by two opposing classes of enzymes including histone acetyltransferases (hac) and histone deacetylases (hdacs), the balance between these enzymes determines the acetylation level of histone. hdac activity leads to histone deaceylation and chromatin compaction resulting in gene silenced. histone deacetylation of tumor suppressor genes leads to tumorigenesis . histone deacetylase inhibitors are the compounds that inhibit hdac activity structurally classified into five families, including short-chain fatty acids (e.g., butyrates), hydroxamic acids (e.g., trichostatin a), cyclic tetrapeptides containing a 2-amino-8-oxo-9,10-epoxy-decanoyl (aoe) moiety (e.g., trapoxin a), cyclic peptides (e.g., apicidin) and benzamides (e.g., ms-27-275). hdacis inhibit cell growth and induce apoptosis in various cancers .
previously, we evaluated the effect of several histone deacetylase inhibitors on various cell lines of hepatocellular cancer and colon cancer which encourage us to design this research. the aim of this study was to evaluate the effect of sodium butyrate in comparison with trichostatin a (tsa) on p21waf1/cip1 expression in colon carcinoma.
Materials and methods: sw1116 cells were cultured with a density of 5 × 10 5 cells per well and allowed to adhere for 24 h and subsequently treated with sodium butyrate and trichostatin a. after 24, 48, of the treatment, mtt assay and real-time quantitative rt-pcr were achieved to determine cell viability and gene expression respectively.
Results: our findings suggest that sodium butyrate and tsa can significantly inhibit cell growth and restore p21waf1/cip1 gene reactivation. reduction of cell viability by 50% (ic50) required 5 mmol/l sodium butyrate and 1 µmol/l tsa for 24 h. using quantitative rt-pcr, sodium butyrate and tsa indicated significant increased p21 at different time periods (24, 48, and 72 h). the relative expression of p21waf1/cip1 in the groups treated with sodium butyrate were 1.4, 1.9, and 2.4 (p < 0.005) and in the groups treated with tsa were 1.7, 2.3, and 3.1 (p < 0.001) in different time periods respectively.
Conclusion: histone deacetylase inhibitors can increase histone acetylation resulting in reactivation of p21waf1 gene expression in human colon cancer sw1116 cell line.
Keywords: sodium butyrate, trichostatin a, p21waf1/cip1, colon cancer