Apoptosis-Inducing Effects of Short-Chain Fatty Acids-Rich Fermented Pistachio Milk in Human Colon Carcinoma Cells

Pistachio milk (PM), an extraction product of pistachio, is protein- and fat-dense food. Short-chain fatty acids (SCFAs) are known for inducing cytotoxicity and apoptosis in colon carcinoma cells. This study aimed to find an optimal combination of probiotics that can produce a higher amount of SCFAs in PM. In addition, the anti-cancer effect of fermented PM on human colon carcinoma cells (Caco-2) was determined. The combinations of probiotics were as follows: Streptococcus thermophilus + Lactobacillus bulgaricus (C); C + Lactobacillus acidophilus (C-La); C + Lactobacillus gasseri (C-Lg); C + Bifidobacterium bifidum (C-Bb). The results indicated that fermented PM was produced after a short fermentation time in all the probiotics combinations. C-Bb produced up to 1.5-fold more acetate than the other probiotics combinations did. A significant amount of cytotoxicity, i.e., 78, 56, and 29% cell viability was observed in Caco-2 cells by C-Bb-fermented PM at 1, 2.5 and 5%, respectively. C-Bb-fermented PM (5%) induced early and late apoptosis up to 6-fold. Additionally, Caco-2 cells treated with C-Bb-fermented PM significantly induced the downregulation of α-tubulin and the upregulation of cleaved caspase-3, as well as nuclear condensation and fragmentation. Our data suggest that fermented PM, which is rich in acetate, may have the potential as a functional food possessing anti-colon cancer properties.

Colorectal keratins: Integrating nutrition, metabolism and colorectal health

The colon mucosa is lined with crypts of circa 300 cells, forming a continuous barrier whose roles include absorption of water, recovery of metabolic energy sources (notably short chain fatty acids), secretion of a protective mucus barrier, and physiological signalling. There is high turnover and replenishment of cells in the mucosa, disruption of this may lead to bowel pathologies including cancer and inflammatory bowel disease. Keratins have been implicated in the processes of cell death, epithelial integrity, response to inflammation and as a result are often described as guardians of the colonic epithelium. Keratin proteins carry extensive post-translational modifications, the cofactors for kinases, acetyl transferases and other modification-regulating enzymes are themselves products of metabolism. A cluster of studies has begun to reveal a bidirectional relationship between keratin form and function and metabolism. In this paper we hypothesise a mechanistic interaction between keratins and metabolism is governed through regulation of post-translational modifications and may contribute significantly to the normal functioning of the colon, placing keratins at the centre of a nutrition-metabolism-health triangle.

Are proteins a redundant ontology? Epistemological limitations in the analysis of multistate species

Advances in proteomics have exponentially increased the numbers of post-translational modifications identified, the resulting volume of data is overwhelming both databases and empiricists. We review methodologies for chemical and functional PTM assignment. Using β-oxidation as a paradigm, we discuss epistemic limitations and conceptual approaches to resolving them combining relational biology, proteomics, and the erosion of "protein" and "metabolite" as distinct ontologies.

A proteomic analysis of differential cellular responses to the short-chain fatty acids butyrate, valerate and propionate in colon epithelial cancer cells

The short chain fatty acids (SCFAs) are inhibitors of histone deacetylases (HDACi); they are produced naturally in the colon by fermentation. They affect cellular processes at a molecular and transcriptional level, the mechanisms of which may involve large numbers of proteins and integrated pathways. Butyrate is the most biologically potent of the SCFAs in colon epithelial cells, inhibiting human colon carcinoma cell proliferation and inducing apoptosis in vitro. In order to investigate the hypothesis that propionate and valerate possess unique and independent actions from butyrate, we combined proteomic and cellomic approaches for large-scale comparative analysis. Proteomic evaluation was undertaken using an iTRAQ tandem mass-spectrometry workflow and high-throughput High-content Analysis microscopy (HCA) was applied to generate cellomic information on the cell cycle and the cytoskeletal structure. Our results show that these SCFAs possess specific effects. Butyrate was shown to have more pronounced effects on the keratins and intermediate filaments (IFs); while valerate altered the β-tubulin isotypes' expression and the microtubules (MTs); propionate was involved in both mechanisms, displaying intermediate effects. These data suggest distinct physiological roles for SCFAs in colon epithelial function, offering new possibilities for cancer therapeutics.