Investigating the influence of dietary pulse consumption on epigenetic biomarkers of colorectal cancer risk

Diet and lifestyle factors play a significant role in colorectal cancer risk by influencing the epigenetic regulation of tumor suppressor genes. While dietary components, such as pulses, are recognized for their chemo-preventative potential, further research is needed to understand how they modulate epigenetic gene expression to protect against colorectal cancer. Pulses are rich in fiber and phytochemicals, making them promising candidates for dietary interventions. This study aimed to determine if sufficient quantities of high-quality human genomic DNA (gDNA) could be extracted from fecal samples to evaluate how pulse consumption impacts tumor suppressor gene expression. Fecal samples were collected from 23 healthy postmenopausal women (aged 45–70) before and after consuming 100 g of pulses daily for nine months. Total gDNA was extracted using the Quick-DNA Fecal/Soil Microbe Kit, with its concentration and integrity assessed via UV spectrophotometry and agarose gel electrophoresis. The proportion of human DNA in total gDNA was determined using the Femto DNA Quantification Kit. The expression of the tumor suppressor gene N-Myc Downstream-Regulated Gene 4 (NDRG4) was analyzed through RT-qPCR to assess the sufficiency of the extracted human DNA for evaluating diet-mediated gene expression changes. Results showed that human DNA accounted for ≤1% of total fecal gDNA, resulting in limited detectability of NDRG4. Expression was measurable in 21 of 23 participants at all time points, but changes following pulse consumption were highly variable. These changes appeared to correlate with altered acetic acid production. However, due to its low expression levels and inconsistent detectability, NDRG4 is not an ideal biomarker for evaluating the efficacy of dietary interventions like pulse consumption for colorectal cancer chemoprevention. The study concluded that fecal samples are a viable non-invasive approach for dietary chemoprevention research. Future studies should explore the effects of pulse consumption on NDRG4 methylation status to provide a clearer understanding of its epigenetic role in colorectal cancer prevention.