Peptides extracted from common bean (Phaseolus vulgaris L.) non-digestible fraction caused differential gene expression of HCT116 and RKO human colorectal cancer cells

The role in cancer chemoprevention of proteins present in non-digestible fraction of common bean (Phaseolus vulgaris L.) is unknown. The aim was to examine the effect of peptide extracted from two cultivars of the common bean Azufrado Higuera (AH-PE) and Bayo Madero (BM-PE) on a gene expression using human colon cancer cells through a microarray analysis. HCT116 and RKO colon cancer cells were treated with 0.5 mg/mL AH-PE and BM-PE for 24 h; RNA was extracted and the gene expression was analyzed using an Agilent Low Input Quick Amp Labeling assay. In the HCT116 human cells, 511 and 964 genes were affected by the AH-PE and BM-PE treatments, respectively, with 405 genes found to be commonly affected by peptide extracts. In the RKO human cells, 45 and 32 genes were affected significantly by the AH-PE and BM-PE treatments, respectively, with 19 genes common for both extracts. Bioinformatic analysis using Database for Annotation Validation and Integrated Discovery showed that the primary genes affected were involved with oxidation-reduction, response to stimulus, protein phosphatase, MAPK signaling, selenium binding and response to wounding. Ingenuity Pathway Analysis showed that in the HCT116 cell line, NRF-2 related antioxidant enzymes were up-regulated while glutathione redox-related enzymes were down-regulated in the RKO cell line, potentially causing reactive oxygen species (ROS) imbalance. Validation of genes by RT-PCR showed good agreement for the genes with a potential role in cancer proliferation and apoptosis (PDE4B and OSGIN1, and KRT19 and EEF1A2). This study discovered, for the first time, 8 differentially expressed genes to be similar for both human colon cancer cell lines triggered by both bean cultivars, namely C11orf31, C9orf169, EMP1, GEM, PLIN2, SUN3, TRIM16L and TXNRD1.