Francisco Sierra-López

Secretion of Extracellular Microvesicles Induced by a Fraction of Escherichia coli: Possible Role in Ovarian Cancer with Bacterial Coinfections

Ovarian cancer (OC) is usually diagnosed at an advanced stage, contributing to its high mortality rate. The presence of concurrent bacterial infections in these patients is a common clinical observation, and the mechanisms by which this coinfection influences tumor progression are still not fully understood. This study investigates the role of polydisperse extracellular vesicles (PEVs) secreted by OC cells in response to bacterial components, aiming to elucidate a potential communication pathway between OC and the bacterial microenvironment. We stimulated a human OC cell line in vitro with a fraction of E. coli. Our results show that this bacterial stimulation significantly increases the secretion of PEVs by cancer cells. A subsequent proteomic analysis of these PEVs revealed an enrichment of proteins, including filamin A, filamin B, alpha-enolase, and heat shock cognate 71 kDa protein. In addition, the PEVs displayed protease activity (on fibronectin and gelatin) and phosphatase activity against para-nitrophenyl phosphate, indicating their capacity to alter cellular signaling. This represents a novel mechanism through which bacterial coinfection may influence the biological behavior of OC if bacteria interact with tumor cells, potentially contributing to their aggressiveness and the challenges associated with their treatment. Our work highlights the importance of studying the interplay between the tumor and its associated microbiota to better understand ovarian cancer progression and identify new therapeutic targets.