Promotion of Extrinsic Apoptosis Pathway in HCT‐116 Human Colorectal Cancer Cell Line by Sodium Butyrate as Histone Deacetylase Inhibitor

Colorectal cancer (CRC) has already been considered the fourth leading cause of mortality worldwide as the genes involved in apoptotic pathways and alterations of reversible epigenetic have an important role in the progression of CRC.

The current study aimed to evaluate the effect of sodium butyrate as a histone deacetylase inhibitoron the alterations of the gene expression of FAS, Fas ligand (FASL), Deathreceptor4(DR4), Deathreceptor5(DR5), and tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) in HCT‐116 CRC cell line.

HCT‐116 cell line was cultured in Dulbeccos Modiied EagleMedium. The cytotoxicity effect of sodium butyrate on HCT‐116 was evaluated using 3‐(4, 5‐dimethylthiazol‐2‐yl)‐2, 5‐diphenyltetrazolium bromide assay for three incubation times (i.e., 24, 48, and 72 h). The half‐maximal inhibitory concentration (IC50) values were determined. The optimum concentration was within the range of 6.25‐200 mM. The cellular ribonucleic acid was extracted, and complementarydeoxyribonucleic acid was synthesized. Finally, the alterations of the gene expression of FAS, FASL, DR4, DR5, and TRAILwere assessed by real‐time polymerase chain reaction (PCR).

TheIC50levels for three incubation times were 50, 12.5, and 6.25 mM, respectively. The obtained results of real‐time PCR demonstrated a significant increase in the gene expression of TRAIL, DR5, and FASin comparison to that of the untreated cells as the control group at the three incubation times. The DR4gene expression significantly increased in comparison to that reported for the control group at 48 and72 h of incubation. In addition, FASLgene expression remarkably decreased at the three incubation times.

Sodium butyrate could show cytotoxicity effect on CRC cell lines through the induction of death receptors in the extrinsic apoptotic pathway. The obtained results of this study revealed that the optimum effect of sodium butyrate is an incubation time‐dependent and concentration‐dependent manner.