Harnessing microvesicles from plantaricin-enhanced stem cells to trigger apoptosis in colon cancer cells

Colorectal cancer (CRC) remains a leading cause of cancer-related mortality, necessitating the development of selective and cell-free therapeutic strategies. This study evaluated the pro-apoptotic potential of microvesicles (MVs) derived from plantaricin-preconditioned mesenchymal stem cells (MSCs) against CRC cells.

Human bone marrow-derived MSCs were preconditioned with a sub-IC₅₀ concentration of plantaricin (10 µg/mL). MVs were isolated from conditioned media by differential ultracentrifugation and characterized using flow cytometry (CD9, CD63, CD81), dynamic light scattering, and protein quantification. HT-29 colorectal cancer cells and HEK-293 normal cells were treated with naïve or plantaricin-enhanced MVs. Cell viability was assessed by MTT assay, apoptosis by Annexin V/PI flow cytometry, and expression of apoptosis-related genes (P53, BAX, BCL-2) by qRT-PCR.

Plantaricin-preconditioned MVs exhibited a reduced mean diameter (253 nm vs. 618 nm) and higher protein content (1107 vs. 983 µg/mL). These MVs significantly decreased HT-29 cell viability with a lower IC₅₀ than naïve MVs (39.10 µg/mL vs. 52.43 µg/mL, p < 0.0001), while showing no significant cytotoxicity toward HEK-293 cells (p > 0.05). Total apoptotic HT-29 cells modestly increased from 6.37% in controls to 8.37% (p < 0.01) and 11.15% (p < 0.001) following treatment with naïve and plantaricin-enhanced MVs, respectively. P53 and BAX were upregulated (up to 3.5-fold, p < 0.001), whereas BCL-2 was downregulated (0.4-fold, p < 0.001).

Plantaricin-enhanced MSC-derived MVs promoted an apoptosis-associated response in CRC cells, supporting their potential as a cell-free approach for further investigation in colorectal cancer.