Use of the J774A.1 Cell Line as a Model in the In Vitro Study of Extracellular Vesicle Secretion from Histiocytic Sarcoma in Patients with Bacterial Co-Infections.

Histiocytic sarcoma (HS) is an aggressive hematological malignancy whose transformed cells exhibit morphological and immunophenotypic characteristics similar to macrophages, and arises de novo or as part of a clonal 'evolution' of other pre-existing hematological neoplasms. This study investigates the potential use of the J774A.1 cell line (a cell line derived from murine tumor cells, commonly used in macrophage research) as a research model to study the role of polydisperse extracellular vesicles (PEVs) secreted by the HS cells, considering that bacterial infections are common in patients with cancer, including HS. The influences of bacterial components on tumor progression are still not fully understood. We stimulated the J774A.1 cell line in vitro with a fraction of E. coli, and our results show that the bacterial stimulation increases the secretion of PEVs by these cells. Comparative results of J774A.1 cells with PEVs using confocal and scanning electron microscopy with micrographic reports of HS histological slides (from several cited mammal species, including humans) suggest a possible relationship of large PEVs with marks, footprints, or traces of possible large PEVs disrupted in the HS of these reports. A subsequent proteomic analysis of these PEVs revealed a diverse subcellular origin of their components, such as proteins including: Triosephosphate isomerase (TPI), Heat shock cognate 71 kDa, Apolipoprotein A-1, Rho GDP-dissociation inhibitor 1, GAPDH, Galectin, Moesin, globular Actin, and Annexin. These results highlight the importance of studying the interplay between HS, other hematological cancers, and bacterial infections to better understand the progression of this cancer, identify new therapeutic targets, and emphasize the importance of preventing bacterial infections in cancer patients. Furthermore, the results demonstrate the potential use of the stimulated J774A.1 cell line for research on HS-related PEVs.