Ovarian cancer-excreted exosomal miR-199a-5p suppresses tumor metastasis by targeting hypoxia-inducible factor-2𝛼 in hypoxia microenvironment

Dear editor,Ovarian cancer is one of the most prevalent gynecological malignant tumors.Its five-year overall survival rate is less than 30%,mostly due to advanced metastasis and chemotherapy resistance[1].However,the mechanisms involved in ovarian cancer metastasis are still poorly understood.Hypoxia is a tumor microenvironment(TME)factor that facilitates tumor progression[2].Changes in TME and cross-talk signaling pathway is crucial for ovarian cancer metastasis and indicate that these tumor biological characteristics are ruled by lots of conserved mechanisms[3,4].Exosomes are crucial signalosomes between various cell types crosstalk and can carry complex mRNAs and microRNAs(miRNAs)functions between cells[5].Tumor-derived exosomes(TDEs)have been shown to not only contribute to TME remodeling but also as a contributor to premetastatic niche formation[6].There are evidence showing that cancer-secreted miRNAs may mediate cell-cell communication in many diseases,including ovarian cancer.For instance,Liu X et al.