Effect of citric acid on Bioavailability and apoptosis induction in human colorectal Adenocarcinoma cell line (HT29)

Colorectal adenocarcinoma is one of the common causes of death due to weak response to common therapies. In this study, the effect of citric acid on bioavailability and apoptosis of the human colorectal adenocarcinoma cell line (HT29) was examined. Citric acid is a naturally organic acid that commonly found in citrus and is considered as a physiological inhibitor of enzymes involved in glycolysis pathway to remove cancer cells.

In this study, HT-29 colorectal adenocarcinoma cancer cells were cultured in DMEM medium with 10% bovine serum. The cells were treated in 400, 800 and 1600 μg/ml concentrations of citric acid and incubated at 24, 48 and 72 hours respectively. Cell growth was analyzed by MTS kit and apoptosis was analyzed three times by flow- cytometry using an Annexin V-FITC/PI kit according to the manufacturers protocol.

The results of bioavailability of treated HT-29 cells with different concentrations (400, 800 and 1600 μg/ml) of citric acid, after trinary incubation time (24, 48 and 72 hours) using the MTS assay showed that, bioavailability of HT-29 cell line decreased at all concentrations of citric acid in a time dependent manner. Also, the results of the apoptosis induction in treated HT-29 cell line with different concentrations (400, 800 and 1600 μg/ml) of citric acid, after trinary incubation time (24, 48 and 72 hours) using Annexin V-FITC/PI test showed that the percentage of the early and late apoptosis cells increased with increasing citric acid concentration and incubation time, which increased the percentage of apoptosis compared to the control group is significant in all three times of 24, 48 and 72 hours.

The results indicate that citric acid can reduce the bioavailability of colorectal adenocarcinoma cells by inducing apoptosis pathway.