Investigating Short-Chain Fatty Acids Effects on Extracellular Vesicles Production in Colorectal Cancer

Colorectal cancer (CRC) is the third most diagnosed and the second leading cause of cancer-related deaths globally, often due to late detection and limited treatment options. Recent studies have linked alterations in gut microbiota to CRC, particularly emphasizing the role of short-chain fatty acids (SCFAs) like acetate, propionate, and butyrate in shaping the tumor microenvironment (TME). SCFAs contribute to CRC pathogenesis by inducing lysosomal membrane permeabilization, cell cycle arrest, and apoptosis in cancer cells. Extracellular vesicles (EVs) are membrane-bound vesicles that facilitate intercellular communication and have gained attention as promising non-invasive biomarkers for cancer diagnosis and treatment monitoring. EVs participate in cellular response mechanisms to external stimuli by transferring proteins, lipids, and nucleic acids between cells, thus modulating target cell behavior and promoting coordinated responses to stress and environmental challenges. This process is essential for cellular adaptation and plays a significant role in pathophysiological processes, including tumor progression and immune modulation, making EVs highly relevant in clinical research. This study examined the impact of SCFAs on EV production and phenotype in CRC cells. The results indicated a notable increase in EV-sized particles following SCFA treatment of colorectal cell lines, particularly in the SW480 CRC cell line. For CRC cell lines, while co-precipitated protein levels remained stable, there was a slight decrease in cellular DNA and an increase in EV-associated DNA. KRAS-mutant SW480 cells exhibited the most pronounced response, emphasizing their heightened sensitivity to SCFA. Notably, microsatellite instability - a key biomarker for immunotherapy in CRC - was detected in both small and large EV populations from BRAF-mutant RKO cells after SCFA treatment, even at low DNA concentrations. These findings underscore the potential of EVs for non-invasive detection of molecular markers, paving the way for further exploration of their role in precision oncology.