Cancer exosome-derived miR-9 and miR-181a promote the development of early-stage MDSCs via interfering with SOCS3 and PIAS3 respectively in breast cancer.

Mengmeng Jiang, Wenwen Zhang, Rui Zhang, Pengpeng Liu, Yingnan Ye, Wenwen Yu, Xiaojing Guo, Jinpu Yu

Oncogene 2020 Jun

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We previously identified that the development of early-stage myeloid-derived suppressor cells (eMDSCs) in breast cancer with high IL-6 (IL-6high) expression was correlated with the SOCS3 deficiency-dependent hyperactivation of the JAK/STAT signaling pathway. However, the regulatory mechanisms have not yet been elucidated. In this study, we aimed to investigate how the posttranscriptional regulation mediated by cancer exosome-derived miRNAs affected the JAK/STAT signaling pathway and the development of eMDSCs. Using miRNA microarray, we screened miR-9 and miR-181a which were exclusively upregulated in eMDSCs and inversely associated with SOCS3 expression. We found both miRNAs promoted the amplification of immature eMDSCs with the strong suppression on T-cell immunity in mice and humans. Furthermore, miR-9 and miR-181a promoted 4T1 tumor growth and immune escape via enhancing eMDSCs infiltration in situ. But miR-9 and miR-181a stimulated eMDSCs development by separately inhibiting SOCS3 and PIAS3, two crucial regulators in the negative feedback loop of the JAK/STAT signaling pathway. Elevated miR-9 and miR-181a in eMDSCs was derived from tumor-derived exosomes, and blocking the exosome release could fully attenuate the miRNA-mediated regulation on eMDSCs development. In summary, our findings indicated that tumor exosome-derived miR-9 and miR-181a activated the JAK/STAT signaling pathway via targeting SOCS3 and PIAS3, respectively, and thus promoted the expansion of eMDSCs which might provide potential therapeutic target for IL-6high breast cancer treatment.

Citation

Mengmeng Jiang, Wenwen Zhang, Rui Zhang, Pengpeng Liu, Yingnan Ye, Wenwen Yu, Xiaojing Guo, Jinpu Yu. Cancer exosome-derived miR-9 and miR-181a promote the development of early-stage MDSCs via interfering with SOCS3 and PIAS3 respectively in breast cancer. Oncogene. 2020 Jun;39(24):4681-4694