Cryptotanshinone alleviates immunosuppression in endometriosis by targeting MDSCs through JAK2/STAT3 pathway.

Endometriosis (EMS), a well-recognized chronic inflammatory disorder, characterized by significant immune dysregulation, in which myeloid-derived suppressor cells (MDSCs) are essential for facilitating immunosuppression and driving to disease progression. Cryptotanshinone (CTS) is an active compound capable of modulating MDSC-mediated immunosuppression; however, its therapeutic effects and mechanisms in the treatment of EMS remain unclear. This study aims to investigate the therapeutic potential of CTS in modulating MDSCs through JAK2/STAT3 signaling pathway and to evaluate its effects on immune microenvironment and endometriotic lesion growth in EMS. Transcriptomic data (GSE141549) and single-cell RNA sequencing data (GSE213216) were analyzed to compare immune cell populations in control endometrium (CE), eutopic endometrium (EuE) and ectopic endometrium (EcE) of patients with EMS. Network pharmacology analysis, surface plasmon resonance (SPR) and cellular thermal shift assay (CETSA) were utilized to explore the molecular mechanism of CTS's effects on MDSCs. A C57BL/6J EMS mice model was established to evaluate CTS's influence on MDSC-mediated immune response in vivo. Flow cytometry and immunofluorescence were used to analyze the immune cell populations, particularly MDSCs and CD8+ T cells. Ex vivo bone marrow (BM)-derived MDSCs were prepared to investigate the modulatory activities of CTS on the frequency and function of MDSCs. The impacts of CTS on JAK2/STAT3 pathway were further examined by western blot. Bioinformatic analysis revealed that, among the three progression stages (CE, EuE, and EcE), the EcE stage exhibited a relatively elevated level of MDSCs and a reduced level of CD8+ T cells. Network pharmacological analysis, along with SPR and CETSA identified that CTS potentially modulates MDSCs in EMS by targeting the JAK2/STAT3 pathway. In vivo studies demonstrated that a relatively high dose of CTS treatment (60mg/kg) effectively inhibited lesion growth, reduced the population of MDSCs, and enhanced CD8+ T cell infiltration. Ex vivo experiments showed that CTS decreased the BM-derived MDSC frequency and rescued the suppressive ability of MDSC upon CD8+ T cells in a dose-dependent manner. Further mechanism analysis confirmed that CTS modulates the expression of immunosuppressive genes and proteins associated with MDSCs through JAK2/STAT3 pathway. This study is the first to demonstrate that CTS is a promising natural compound for EMS treatment by inhibiting MDSC accumulation and modulating MDSC-mediated immune responses. Its therapeutic efficacy is linked to the modulation of the JAK2/STAT3 signaling pathway.

Xie L ，Zhong Y ，Chen Y ，Wang Y ，Xian P ，Liu S ，Xin X ，Chen Y ，Guan Y ，Li K ... -  《-》

Receptor Tyrosine Kinase Inhibitor Sunitinib as Novel Immunotherapy to Inhibit Myeloid-Derived Suppressor Cells for Treatment of Endometriosis.

Endometriosis is a common, benign, and hormone-dependent gynaecological disorder that displays altered immunoinflammatory profiles. Myeloid-derived suppressor cells (MDSCs) suppressed immunosurveillance in endometriosis in human and mouse model. Receptor tyrosine kinase inhibitor Sunitinib can induce MDSC apoptosis and suppress the progression of cancer. However, the effects of Sunitinib on MDSCs in endometriosis and the underlying mechanism are not clear. In this study, we employed an animal study of the endometriosis model in mice for treatment of Sunitinib. After syngeneic endometrium transplantation and treatment, endometriotic lesion volume, weight, and histology were compared. Peritoneal fluid, peripheral blood, and bone marrow MDSC subsets and their molecular signaling were monitored by flow cytometry. Peritoneal cytokines were assayed by ELISA. The gene expression profiles of isolated CD11b+Ly6G+Ly6Clo cells were studied by RNA sequencing. We found that Sunitinib significantly decreased the endometriotic lesion size and weight after 1 and 3 weeks, and decreased p-STAT3 activation in MDSCs after 1 week of treatment. In the first week, Sunitinib specifically increased the G-MDSC population in peritoneal fluid but the isolated CD11b+Ly6G+Ly6Clo MDSCs after Sunitinib treatment were presented as mature polynuclear MDSCs, while the control group had immature mononuclear MDSCs. Importantly, we found Sunitinib differentially suppressed gene expressions of immunosuppressive function and differentiation in peritoneal G-MDSCs. Apelin signaling pathway associated genes and inflammation related genes were upregulated, and amino acid metabolism regulator genes were downregulated in bone marrow G-MDSCs. For endometriotic lesions, the PPARG gene governing glucose metabolism and fatty acid storage, which is important for the development of endometriosis was upregulated. In conclusion, Sunitinib inhibited endometriotic lesions, by promoting peritoneal fluid MDSCs maturation and inhibiting the immunosuppressive function. These findings suggest that Sunitinib changed the immune microenvironment and inhibited the development of endometriosis, which has potential therapeutic effects as novel immunotherapy to promote MDSCs maturation, differentiation, and metabolism for the treatment of endometriosis.

He Y ，Hung SW ，Liang B ，Zhang R ，Gao Y ，Chu CY ，Zhang T ，Xu H ，Chung JPW ，Wang CC ... -  《-》

Inhibition of JAK2/STAT3 reduces tumor-induced angiogenesis and myeloid-derived suppressor cells in head and neck cancer.

Angiogenesis is an essential event in tumor growth and metastasis, and immune system also contributes to the tumor evasion. Emerging evidences have suggested the bidirectional link between angiogenesis and immunosuppression. Myeloid-derived suppressor cell (MDSC) is a kind of immunosuppressive cells and plays an important role in this process. However, the actual regulatory mechanisms of angiogenesis and MDSCs in head and neck squamous cell carcinoma (HNSCC) were unclear. In this study, through analyzing the immunohistochemistry staining of human HNSCC tissue microarray, we found that the microvascular density (MVD) was significantly increased in HNSCC patients. We also characterized angiogenic factors p-STAT3, VEGFA, CK2, and MDSCs marker CD11b in HNSCC tissue array, and found the close expression correlation among these markers. To determine the role of JAK2/STAT3 pathway in tumor microenvironment of HNSCC, we utilized AG490 (an inhibitor of JAK2/STAT3) for further research. Results showed that inhibition of JAK2/STAT3 suppressed angiogenesis by decreasing VEGFA and HIF1-α both in vitro and vivo. Moreover, in HNSCC transgenic mouse model, inhibiting JAK2/STAT3 not only suppressed angiogenesis but also reduced MDSCs in the tumor microenvironment through suppressing VEGFA and CK2. Our findings demonstrated the close relationship between angiogenesis and MDSCs in HNSCC, and inhibition of JAK2/STAT3 could reduce tumor-induced angiogenesis and decrease MDSCs.

Liu JF ，Deng WW ，Chen L ，Li YC ，Wu L ，Ma SR ，Zhang WF ，Bu LL ，Sun ZJ ... -  《-》

S100A4 mediates the accumulation and functions of myeloid-derived suppressor cells via GP130/JAK2/STAT3 signaling in acute myeloid leukemia.

Acute myeloid leukemia (AML) is an immunosuppressive hematologic malignancy with a poor prognosis. An immunosuppressive microenvironment blunts AML therapy. However, the prognostic and therapeutic roles of the factors that mediate immunosuppression in AML remain elusive. S100 calcium-binding protein A4 (S100A4) was identified as an immunosuppression-mediating factor by analyzing The Cancer Genome Atlas AML project (TCGA-LAML) transcriptome data and data from AML-bearing mice and AML patients. The S100A4-mediated signaling pathway in myeloid-derived suppressor cells (MDSCs) was evaluated. Elevated S100A4 expression was positively associated with worse survival of AML patients, MDSCs, macrophages and immune checkpoints. S100A4 silencing downregulated the expression levels of MDSC-associated CD14, CCR2 and CCL2, reduced MDSC expansion and impaired MDSC-mediated inhibition of T cell activation and proliferation. S100A4-based prognostic signature (SPS) was an independent risk factor for AML patients. The high-risk group based on SPS was not only associated with adverse survival, MDSCs and macrophages and immune checkpoints but also insensitive to 25 chemotherapy drugs. It was also found that CCAAT enhancer binding protein beta (CEBPB) mediated S100A4 transcription. CEBPB silencing downregulated the expression levels of MDSC-associated CD14, CCR2 and CCL2. Mechanistically, S100A4 activated GP130/JAK2/STAT3 signaling in MDSCs by interacting with the cytokine-binding domain of GP130. Moreover, S100A4 mediated MDSC expansion through JAK2/STAT3 signaling. This study uncovers the critical role of S100A4 in MDSC accumulation, and S100A4-based prognostic signature may guide chemotherapy sensitivity in patients with AML.

Peng Y ，Zhang J ，Zhang T ，Wang C ，Bai J ，Li Y ，Duan J ，Fan D ，Fu W ，Liang X ，Xie X ，Qi X ，Hong W ，He Y ，Wu C ，Zhou J ，Chen P ，Zeng H ，Dai Y ，Yu W ，Bai H ，Guo P ，Zeng Z ，Zhang Q ... -  《-》

Cell-intrinsic PD-L1 signaling drives immunosuppression by myeloid-derived suppressor cells through IL-6/Jak/Stat3 in PD-L1-high lung cancer.

Some patients with non-small-cell lung cancer (NSCLC) benefit from immune checkpoint inhibitors (ICIs) despite programmed death-ligand 1 (PD-L1) expression. To address the mechanism of ICI resistance in PD-L1-positive NSCLC, we investigated the role of tumor-cell-intrinsic function of PD-L1 in interleukin (IL)-6-mediated immunosuppression. Cohorts of NSCLC patients treated with ICI and public datasets were analyzed. PD-L1-overexpressing and PD-L1-knockdown NSCLC cells were submitted to RNA-seq, in vitro analyses, chromatin immunoprecipitation-qPCR, CUT&Tag, and biochemical assays. Human myeloid-derived suppressor cells (MDSCs) sorted from peripheral blood mononuclear cells were co-cultured with NSCLC cells and then assessed for their immunosuppressive activity on T-cells. Mouse Lewis lung carcinoma (LLC) cells with PD-L1 overexpression or knockdown were subcutaneously injected into wild-type or PD-1-knockout C57BL/6 mice in the presence of IL-6 and/or PD-1 blockade. In the ICI cohort with RNA-seq data, the IL-6/Jak/Stat3 pathway was enriched, and IL-6 expression was higher in patients with PD-L1-high NSCLCs who did not respond to ICIs. In another cohort, a higher baseline serum IL-6 level was associated with poor clinical outcomes after ICI therapy. IL-6 expression and the IL-6/Jak/Stat3 pathway were enhanced in PD-L1-high NSCLCs in the ICI cohorts and The Cancer Genome Atlas analysis. IL-6 expression correlated positively with tumor-infiltrating MDSCs in NSCLCs. In NSCLC cells, PD-L1 activated Jak2/Stat3 signaling by binding to and inhibiting protein tyrosine phosphatase 1B. PD-L1 also bound to p-Stat3 in the nucleus, thus promoting the activity of p-Stat3 in the transcription of several cytokines (IL-6, TGF-β, TNF-α, IL-1β) and chemokines. PD-L1-overexpressing NSCLC cells enhanced the migration and immunosuppressive activity of human MDSCs in vitro, mediated by IL-6 and CXCL1. In both wild-type and PD-1-knockout mice, PD-L1-overexpressing LLC tumors were infiltrated by increased MDSCs with high immunosuppressive function, increased Tregs, and decreased granzyme B+ or IFNγ+ CD8 T-cells. These responses were mediated by IL-6 secreted from PD-L1-overexpressing tumor cells. Combined blockade of PD-1 and IL-6 was effective in tumor control and decreased MDSCs while increasing granzyme B+ or IFNγ+ CD8 T-cells. The tumor-cell-intrinsic function of PD-L1 drives immunosuppression and tumor progression through the PD-L1/Jak/Stat3/IL-6/MDSC axis. This pathway represents a potential therapeutic target to improve ICI efficacy in PD-L1-high NSCLC.

Jeong H ，Koh J ，Kim S ，Yim J ，Song SG ，Kim H ，Li Y ，Lee SH ，Chung YK ，Kim H ，Lee CH ，Kim HY ，Keam B ，Lee SH ，Chung DH ，Jeon YK ... -  《Journal for ImmunoTherapy of Cancer》