In:
Cancer Research, American Association for Cancer Research (AACR), Vol. 80, No. 16_Supplement ( 2020-08-15), p. 985-985
Abstract:
Early-stage myeloid-derived suppressor cells (eMDSCs) are a newly defined subset of myeloid-derived suppressor cells (MDSCs) that accumulate densely in tumors and potently promote tumor growth and metastasis by suppressing antitumor immune responses in vitro and in vivo. We previously identified a subset of eMDSCs in human breast cancer with a characteristic phenotype of Lin-HLA-DR-CD33+. We also found that SOCS3 deficiency and sustained activation of the JAK/STAT signaling pathway are critical molecular events coordinating the differentiation of eMDSCs, although the distinct molecular regulation has not been fully elucidated. Herein, we genetically constructed conditional SOCS3 knockout mice with SOCS3 deficiency specifically in the myeloid linage (SOCS3MyeKO). We delineated that the number of eMDSCs in SOCS3MyeKO mice (eMDSCsSOCS3KO) with the murine GMP phenotype increased significantly, and these cells suffered from a differentiation block in the myeloid lineage. To explore which pathways participated in dysfunctional eMDSC differentiation, we performed whole-genome RNA sequencing and miRNA microarray on CD11b+Gr-1+ cells, eMDSCsfl/fl and eMDSCsSOCS3KO to screen the potential regulatory ceRNA network in eMDSCsSOCS3KO. CD11b+Gr-1+ cells isolated from SOCS3fl/fl mouse spleens were used as mature myeloid cell controls. The transcriptome results and corresponding intervention experiment revealed that the differentiation block in eMDSCsSOCS3KO was caused by SOCS3 deficiency-mediated limited autophagy activation in an AMPK-independent manner. The results of miRNA microarray and RNA sequencing demonstrated that miR-155 overexpression and Wnt/β-catenin pathway activation were involved in the SOCS3 knockout-mediated myeloid differentiation block and autophagy repression. Further experiments revealed that miR-155 was induced by activation of the STAT3/NK-κB pathway upon SOCS3 deficiency, which consequently activated the Wnt/β-catenin pathway via targeting C/EBPβ. Furthermore, applying a specific miR-155 antagonist or the autophagy agonist rapamycin efficiently suppressed tumor growth and eMDSC infiltration in vivo. Overall, these findings indicated that SOCS3 deficiency blocked autophagy-dependent myeloid differentiation of e-MDSCs via the miR-155/C/EBPβ/Wnt axis, and thus targeted therapy against this pathway could be a potential therapeutic target in breast cancer. Citation Format: Wenwen Zhang, Mengmeng Jiang, Rui Zhang, Pengpeng Liu, Yingnan Ye, Xiubao Ren, Wenwen Yu, Jinpu Yu. SOCS3 deficiency blocked autophagy-dependent myeloid differentiation of early-stage myeloid-derived suppressor cells via the miR-155/C/EBPβ/Wnt axis [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 985.
Type of Medium:
Online Resource
ISSN:
0008-5472
,
1538-7445
DOI:
10.1158/1538-7445.AM2020-985
Language:
English
Publisher:
American Association for Cancer Research (AACR)
Publication Date:
2020
detail.hit.zdb_id:
2036785-5
detail.hit.zdb_id:
1432-1
detail.hit.zdb_id:
410466-3
Permalink