Tumor-derived small extracellular vesicles promote breast cancer progression by upregulating PD-L1 expression in macrophages

Abstract

Background The metastasis of breast cancer (BC) is a complex multi-step pathological process, strictly dependent on the intrinsic characteristics of BC cells and promoted by a predisposing microenvironment. Although immunotherapy has made important progress in metastasis BC, the heterogeneity of PD-L1 in tumor associated macrophages (TAMs) in BC and the underlying mechanisms in the metastasis development of BC are still not completely elucidated. Small extracellular vesicles (sEVs) represent essential interaction mediators between BC cells and TAMs. It is worth noting to explore the underlying mechanisms typical of sEVs and their role in the metastasis development of BC. Methods The structure of sEVs was identified by TEM, while the particle size and amounts of sEVs were detected by BCA and NTA analysis. The specific PD-L1 + CD163 + TAM subpopulation in metastasis BC was identified by scRNA-seq data of GEO datasets and verified by IHC and IF. The function of TAMs and sEVs in metastasis BC was explored by RT-qPCR, WB, IF, flow cytometry and in vivo experiment. The expression profiles of plasma sEVs-miRNA in relation to BC metastasis was analyzed using next-generation sequencing. Further detailed mechanisms of sEVs in the metastasis development of BC were explored by bioinformatics analysis, RT-qPCR, WB and luciferase reporter assay. Results In this study, we identified that the immunosuppressive molecule PD-L1 was more abundant in TAMs than in BC cells, and a specific PD-L1 + CD163 + TAM subpopulation was found to be associated with metastasis BC. Additionally, we found that BC cells-derived sEVs can upregulate the PD-L1 expression and induce the M2 polarization, enhancing the metastasis development both in vitro and in vivo. Also, Clinical data showed that sEV-miR-106b-5p and sEV-miR-18a-5p was in relation to BC metastasis development and poor prognosis of BC patients. Further mechanistic experiments revealed that BC-derived sEV-miR-106b-5p and sEV-miR-18a-5p could synergistically promoted the PD-L1 expression in M2 TAMs by modulating the PTEN/AKT and PIAS3/STAT3 pathways, resulting in the enhancement of the BC cells invasion and metastasis. Conclusions Our study demonstrated that BC-derived sEVs can induce metastasis in BC through miR-106b-5p/PTEN/AKT/PD-L1 and miR-18a-5p/PIAS3/STAT3/PD-L1 pathways in TAMs. Therefore, the inhibition of these specific interactions of signaling pathways would represent a promising target for future therapeutic strategies for treatment of BC.

Extracellular Vesicles lysis: a guide for the release of biomarkers to be used in cancer diagnostics

“…And again in the study by Xu et al(Xu et al, 2023) Temperini et al, 2022). As in the study by Sun et al(Sun et al, 2021) that determined CD63, TSG101, β-actin,…”

“…Thanks to the use of Trizol, many studies have recognized various tumor biomarkers for diagnostic and prognostic purposes (Liu et al, 2021;S. Shin et al, 2021;Xu et al, 2023;Xue et al, 2019;Zhao et al, 2023). As in the study by Liu et al(Liu et al, 2021) they identified miR-21-5p overexpression in patients with breast cancer, liver cancer, lung cancer, cervical cancer, and ovarian cancer using microarray and RT-PCR analyses.…”

Tumor associated macrophages in breast cancer progression: implications and clinical relevance

“…In a single-cell transcriptomic analysis, PDL1 + TAMs were reported to be immunostimulatory, demonstrated a preference to localize near T cells and were associated with improved clinical outcomes ( 39 ). In another study, increased CD163 + PDL1 + TAM density was associated with advanced stages of BC and metastasis, while PDL1 upregulation was proposed to occur through miRNA mediated gene regulation ( 40 ).…”

The role of extracellular vesicles in circulating tumor cell-mediated distant metastasis

“…For instance, EVs carrying miR-200 promote BC cell colonization in the lung [ 218 ]. BC cells transmit sEV-miR-106b-5p and sEV-miR-18a-5p to macrophages and induce PD-L1 expression through the PTEN/AKT and PIAS3/STAT3 signaling pathways, which also leads to macrophage polarization and the development of BC lung metastasis [ 219 ]. Xia et al [ 220 ] found that BC-derived EVs promote BC lung metastasis by carrying the lncRNA SNHG16 through the miR-892b/PPAPDC1A axis.…”