ATM-AMPKα mediated LAG-3 expression suppresses T cell function in prostate cancer.

Immunotherapy for prostate cancer (PCa) faces serious challenges. Therefore, the co-inhibitory receptors that regulate T cell function of PCa must be elucidated. Here we identified that the inhibitory receptor LAG3 was significantly induced in T cells from PCa patients. Gene array analysis revealed that insufficient ataxia telangiectasia mutated (ATM) gene expression in PCa T cells was responsible for the elevated LAG3 expression. Mechanistically, insufficient ATM expression impaired its ability to activate AMPKα signaling and CD4+ T cell functions, which further enhances the binding of the transcription factors XBP1 and EGR2 to LAG3 promoter. Reconstitution of ATM and inhibition of XBP1 or EGR2 in PCa T cells suppressed LAG3 expression and restored the effector function of CD4+ T cells from PCa. Our study revealed the mechanism of LAG3 upregulation in CD4+ T lymphocytes of PCa patients and may provide insights for the development of immunotherapeutic strategies for PCa treatment.

Single-Cell RNA Sequencing Identifies Intra-Graft Population Heterogeneity in Acute Heart Allograft Rejection in Mouse.

Transplant rejection remains a major barrier to graft survival and involves a diversity of cell types. However, the heterogeneity of each cell type in the allograft remains poorly defined. In the present study, we used single-cell RNA sequencing technology to analyze graft-infiltrating cells to describe cell types and states associated with acute rejection in a mouse heart transplant model. Unsupervised clustering analysis revealed 21 distinct cell populations. Macrophages formed five cell clusters: two resident macrophage groups, two infiltrating macrophage groups and one dendritic cell-like monocyte group. Infiltrating macrophages were predominantly from allogeneic grafts. Nevertheless, only one infiltrating macrophage cluster was in an active state with the upregulation of CD40, Fam26f and Pira2, while the other was metabolically silent. Re-clustering of endothelial cells identified five subclusters. Interestingly, one of the endothelial cell populations was almost exclusively from allogeneic grafts. Further analysis of this population showed activation of antigen processing and presentation pathway and upregulation of MHC class II molecules. In addition, Ubiquitin D was specifically expressed in such endothelial cell population. The upregulation of Ubiquitin D in rejection was validated by staining of mouse heart grafts and human kidney biopsy specimens. Our findings present a comprehensive analysis of intra-graft cell heterogeneity, describe specific macrophage and endothelial cell populations which mediate rejection, and provide a potential predictive biomarker for rejection in the clinic.

In vitro and in vivo anti-metastatic effect of the alkaliod matrine from Sophora flavecens on hepatocellular carcinoma and its mechanisms.

BACKGROUNDS: Hepatocellular carcinoma (HCC) is one of the most prevalent and lethal cancer with high metastasis and recurrence rates. Hypoxia-induced miRNAs and HIF-1α are demonstrated to play essential roles in tumor metastasis. Matrine (C15H24N2O), an alkaloid extracted from Sophora flavescens Aiton, has been used as adjuvant therapy for liver cancer in China. The anti-metastasis effects of matrine on HCC and the underlying mechanisms remain poorly understood. PURPOSE: We aimed to investigate the effects of matrine on metastasis of HCC both in vitro and in vivo, and explored whether miR-199a-5p and HIF-1α are involved in the action of matrine. METHODS: MTT method, colony formation, wound healing and matrigel transwell assays were performed to evaluate the effects of matrine on cell proliferation, migration and invasion. Nude mice xenograft model and immunohistochemistry (IHC) assay were employed to investigate the anti-metastatic action of matrine in vivo. Quantitative real-time PCR, western blot and dual luciferase reporter assay were conducted to determine the underlying mechanisms of matrine. RESULTS: Matrine exerted stronger anti-proliferative action on Bel7402 and SMMC-7721 cells under hypoxia than that in normoxia. Both matrine and miR-199a-5p exhibited significant inhibitory effects on migration, invasion and EMT in Bel7402 and SMMC-7721 cells under hypoxia. Further study showed that miR-199a-5p was downregulated in HCC cell lines, and this microRNA was identified to directly target HIF-1α, resulting in decreased HIF-1α expression. Matrine induced miR-199a-5p expression, decreased HIF-1α expression and inhibited metastasis of Bel7402 and SMMC-7721 cells, while miR-199a-5p knockdown reversed the inhibitory effects of matrine on cell migration, invasion, EMT and HIF-1α expression. In vivo, matrine showed significant anti-metastatic activity in the nude mouse xenograft model. H&E and IHC analysis indicated that lung and liver metastasis nodules were reduced, and the protein expression of HIF-1α and Vimentin were significantly decreased by i.p injection of matrine. CONCLUSIONS: Matrine exhibits significant anti-metastatic effect on HCC, which is attributed to enhanced miR-199a-5p expression and subsequently impaired HIF-1α signaling and EMT. These findings suggest that miR-199a-5p is a potential therapeutic target of HCC, and matrine may represent a promising anti-metastatic medication for HCC therapy.

[Matrine suppresses stemness of hepatocellular carcinoma cells by regulating ß-catenin signaling pathway].

OBJECTIVE: To explore the effects of matrine on the proliferation, tumor cell stemness, ß-catenin transcriptional activity and AKT/GSK3ß/ß-catenin signaling pathway in human hepatocellular carcinoma (HCC) HepG2 and Huh7 cells. METHODS: The proliferation and colony formation ability of HepG2 and Huh7 cells treated with 200, 400, and 800 µg/mL matrine were evaluated with MTT assay and colony formation assay, respectively. Real-time quantitative PCR was performed to detect the mRNA expressions of CD90, epithelial cell adhesion molecule (EpCAM) and CD133, and dual-luciferase assay was used to detect the transcriptional activity of ß-catenin in the treated cells. The effects of matrine on the expressions of protein kinase B (AKT), P-AKT, GSK-3ß, P-GSK-3ß, P-ß-catenin and ß-catenin proteins in the Wnt/ß-catenin signaling pathway were assessed using Western blotting. RESULTS: Matrine inhibited the proliferation of the two HCC cell lines in a time- and concentration-dependent manner. The half-inhibitory concentrations of matrine were 2369, 1565 and 909.1 µg/mL at 24, 48 and 72 h in HepG2 cells, respectively, and were 1355, 781.8, and 612.8 µg/mL in Huh7 cells, respectively. Matrine concentrationdependently suppressed colony formation of the HCC cells, producing significant inhibitory effects at 400 µg/mL P < 0.01) and 800 µg/mL P < 0.001) in HepG2 cells and at 200 µg/mL P < 0.05), 400 µg/mL P < 0.01), and 800 µg/mL P < 0.001) in Huh7 cells. Matrine at 400 and 800 µg/mL significantly inhibited the mRNA expression of CD90, EpCAM and CD133 and the transcriptional level of ß-catenin in both HepG2 and Huh7 cells P < 0.05 or 0.01). Matrine at 400 and 800 µg/mL also significantly decreased the protein levels of ß-catenin, P-AKT and P-GSK-3ß and increased the phosphorylation level of ß-catenin in both of the cell lines. CONCLUSIONS: Matrine inhibits the proliferation, colony formation, and the expressions of tumor stem cell markers CD90, EpCAM and CD133 in both HepG2 and Huh7 cells probably by inhibiting Wnt/ß-catenin signaling pathway and the transcriptional activity ofß-catenin.