ABSTRACT
BACKGROUND: Ovarian cancer (OC) as the most fatal gynecological malignancy worldwide, with epithelial ovarian cancer (EOC) being the predominant and most lethal form, poses a serious threat to human health. LC3-positive extracellular vesicles (LC3+ EVs) promote tumorigenesis by educating CD4+ T cells in a murine melanoma model. However, regulation of LC3+ EVs in human EOC remains largely unknown. METHODS: Differential analysis of Rab8a, Hsp90α and Il6 expression was performed using GEPIA2. The number of LC3+ EVs and the frequency of Heat shock protein 90α+ LC3+ EVs (HSP90α+ LC3+ EVs) in the ascites of EOC patients were tested by flow cytometry. IL-6, IL-10, IFN-γ, IL-4 and TGF-ß were measured by ELISA. CD4+ T cells were isolated from peripheral blood of healthy human donors using MACS magnetic bead technology. RESULTS: Higher Rab8a, Hsp90a and Il6 expression of cancer tissues compared with normal adjacent tissues in OC were found. The level of IL-6 was positively correlated with LC3+ EVs number, HSP90α+ LC3+ EVs percentage in the ascites, and ROMA index of the patient. In addition, elevated IL-6 production by CD4+ T cells induced by LC3+ EVs was observed, which was suppressed by anti-HSP90α or anti-TLR2. CONCLUSIONS: LC3+ EVs level and HSP90α+ LC3+ EVs percentage were associated with elevated IL-6 in the ascites of EOC patients. HSP90α on LC3+ EVs from human EOC could stimulate CD4+ T cell production of IL-6 via TLR2.