Cuiping Liu

A frequent somatic mutation in CD274 3′-UTR leads to protein over-expression in gastric cancer by disrupting miR-570 binding†

Inhibitory costimulatory molecule CD274 expresses in various cancers and contributes to cancer immune evasion by inhibiting T cell activation and proliferation, yet the regulatory mechanisms for CD274 overexpression in cancers are poorly understood. In this study, we discovered a novel mechanism of CD274 expression regulated by miR‐570. A guanine‐to‐cytosine mutation at the 3′‐UTR of CD274 mRNA led to CD274 overexpression by disrupting the miR‐570 binding. The mutations were widely observed in cancers by sequencing of 276 gastrointestinal cancers (esophageal, gastric, colorectal, hepatocellular, and pancreatic cancers). This mutation was significantly associated with CD274 overexpression in gastric cancer (P = 1.44×10−10) and with the pathological features including differentiation grade, depth of tumor invasion, lymph node metastasis, and tumor‐node‐metastases (TNM) stage. These findings suggest a novel regulatory mechanism for CD274 overexpression in gastric cancer mediated by miR‐570 and a somatic mutation in CD274 3′‐UTR, and provide a new insight to gastric carcinogenesis. Hum Mutat 33:480–484, 2012.

A Promoter Region Polymorphism in PDCD-1 Gene Is Associated with Risk of Rheumatoid Arthritis in the Han Chinese Population of Southeastern China

Objective. Programmed cell death 1 (PD-1) induces negative signals to T cells during interaction with its ligands and is therefore a candidate gene in the development of autoimmune diseases such as rheumatoid arthritis (RA). Herein, we investigate the association of PDCD-1 polymorphisms with the risk of RA among Chinese patients and healthy controls. Methods. Using the PCR-direct sequencing analysis, 4 PDCD-1 SNPs (rs36084323, rs11568821, rs2227982, and rs2227981) were genotyped in 320 RA patients and 309 matched healthy controls. Expression of PD-1 was determined in peripheral blood lymphocytes by flow cytometry and quantitative real-time reverse transcriptase polymerase chain reaction. Results. We observed that the GG genotype of rs36084323 was associated with a increased risk for developing RA (OR 1.70, 95% 1.11–2.61, P = 0.049). Patients carrying G/G genotype displayed an increased mRNA level of PD-1 (P = 0.04) compared with A/A genotype and healthy controls. Meanwhile, patients homozygous for rs36084323 had induced basal PD-1 expression on activated CD4+ T cells. Conclusion. The PDCD-1 polymorphism rs36084323 was significantly associated with RA risk in Han Chinese population. This SNP, which effectively influenced the expression of PD-1, may be a biomarker of early diagnosis of RA and a suitable indicator of utilizing PD-1 inhibitor for treatment of RA.

Enhancement of membrane B7-H3 costimulatory molecule but reduction of its soluble form in multiple sclerosis.

PurposeMultiple sclerosis (MS) is an autoimmune disease of the central nervous system mediated by T cells. B7-H3 plays a diverse role in regulating T cell responses. However, its expression and clinical significance in MS are not well known. This study analyzed the expression of membrane B7-H3 (mB7-H3) and levels of soluble B7-H3 (sB7-H3) in MS patients to determine its clinical significance.MethodsPeripheral blood (PB) or cerebrospinal fluid (CSF) samples from healthy controls, other noninflammatory neurological disorders, viral encephalitis, and MS patients were collected. Expression of mB7-H3 on immune cells was detected by flow cytometry. Levels of sB7-H3 in serum or CSF samples were measured by ELISA.ResultsmB7-H3 expression was up-regulated in CSF from MS patients compared to PB (p < 0.001). However, serum or CSF levels of sB7-H3 in MS patients were significantly lower than those in controls (p < 0.05). Relapsing-MS patients had higher CSF mB7-H3 expression than the remitting subgroup. Relapsing-MS patients had decreased serum and CSF sB7-H3 levels compared with the remitting subgroup. Neurological deficits showed negative correlations with serum or CSF sB7-H3 levels, but a positive correlation with CSF mB7-H3 expression. Methylprednisolone therapy significantly elevated sB7-H3 levels and reduced mB7-H3 expression compared with pre-therapy levels. sB7-H3 levels did not correlate with mB7-H3 expression.ConclusionsWe demonstrated enhanced mB7-H3 expression and reduced sB7-H3 levels in MS patients which correlated with the clinical characteristics of MS patients. These results suggest that B7-H3 may be a promising biomarker and associated with the pathogenesis of MS.

TGF-β1 promotes colorectal cancer immune escape by elevating B7-H3 and B7-H4 via the miR-155/miR-143 axis.

Transforming growth factor-beta 1 (TGF-β1) suppresses T cell function, promoting tumor immune escape. Yet, whether the depression of TGF-β1 on T cell function is mediated by co-inhibitory molecules B7-H3 and B7-H4 remains largely unclear. Here, we demonstrated that TGF-β1 elevated the expression of miR-155 in colorectal cancer cells through SMAD3 and SMAD4. The upregulated miR-155 attenuated miR-143 by inhibiting its direct target, the transcription factor CEBPB. Consequently, the direct target genes of miR-143, B7-H3 and B7-H4, were augmented in the cytoplasm and membrane of tumor cells. Over-expression of B7-H3 and B7-H4 in HCT-116 cells induced T cells to secrete TGF-β1 and the immunosuppressive cytokines IL-2, IL-6, and IL-17. Restoration of miR-143 inhibited the growth of HCT-116 xenograft tumors in mice, and also repressed the expression of B7-H3 and B7-H4 in the tumors. Thus, this study reveals the mechanism by which TGF-β1 leads to T cell-mediated tumor evasion through an increase in B7-H3 and B7-H4 expression.

Correlation between B7-H3 expression and rheumatoid arthritis: A new polymorphism haplotype is associated with increased disease risk.

CD276 (B7-H3) is a costimulatory molecule that plays a potent role in T cell responses, however, the role of B7-H3 in autoimmune diseases has not been elucidated. We analyzed B7-H3 expression in rheumatoid arthritis (RA) for the first time and found B7-H3 was significantly up-regulated on monocytes in RA patients, while the levels of soluble B7-H3 in serum were lower than in controls (P < 0.0001). These differences correlated with clinical and laboratory disease parameters and informatory factor TNF-α. Through in vitro experiments, we demonstrated that B7-H3 promoted TNF-α secretion. In addition, a new polymorphism variant, B7-H3-T-A-C-T, was identified and shown to be associated with the incidence of RA and the decreased release of sB7-H3. These results suggest that B7-H3 may be a promising biomarker associated with the pathogenesis of RA. Notably, the new B7-H3-T-A-C-T polymorphism variant is associated with RA risk and might be associated with the release of soluble B7-H3.

Expression of co-stimulatory molecule B7-H4 in patients suffering from rheumatoid arthritis

B7-H4, an inhibitory modulator of T-cell response, is one of the most recently identified cell surface molecules in the B7-CD28 signaling pathway. However, its role in the pathogenesis of rheumatoid arthritis (RA) remains unclear. In the present study, the immunofluorescence staining, confocal laser scanning microscopy and flow cytometry techniques were used to characterize B7-H4 protein expression in RA synovium tissues and peripheral blood mononuclear cell (PBMC) subsets, respectively. Our data showed that the immunolocalization of B7-H4 could be found on the membrane and in the cytoplasm of synoviocytes and CD19(+) B cells in rheumatoid synovium tissues, while B7-H4 was weakly or negatively expressed on CD3(+) T cells, CD14(+) monocytes and CD68(+) macrophages. Moreover, B7-H4 expression was observed in CD34(+) endothelial cells of neovessels in rheumatoid synovium. Flow cytometric analysis also showed that positive B7-H4 expression was found in CD19(+) B cells and CD14(+) monocytes, but not in CD3(+) T cells. Thus, our work identified the expression pattern of B7-H4 in the synovium tissues and PBMC subsets from RA patients, suggesting that B7-H4 involves in the pathological changes of rheumatoid synovium in RA progression, and its detailed biological function needs further investigations.

OX40 signaling is involved in the autoactivation of CD4+CD28− T cells and contributes to the pathogenesis of autoimmune arthritis

BackgroundCD4+CD28− T cells exhibit autoreactive potential in autoimmune disorders, including rheumatoid arthritis (RA). It is not well known which costimulator functions as an alternative second signal in the activation of this subset after CD28 expression is downregulated. Tumor necrosis factor receptor superfamily member OX40 is a key costimulator in the activation of T cells. The aim of this study was to investigate the costimulatory effects of OX40 on CD4+CD28− T cells in autoimmune arthritis.MethodsClinical samples were collected from patients with RA and control subjects. Collagen-induced arthritis (CIA) was induced with collagen type II (CII) in DBA/1 mice. The CD4+CD28−OX40+ T-cell subset and its cytokine production were detected by flow cytometry. After T-cell purification, adoptive transfer was performed in CIA mice. The regulatory role of OX40 was determined by blocking experiments in vitro and in vivo.ResultsOX40 and OX40L were abnormally expressed in patients with RA and CIA mice. Further analysis showed that CD4+CD28−OX40+ T cells accumulated in patients with RA and in animal models. These cells produced higher levels of proinflammatory cytokines and were closely correlated with the clinicopathological features of the affected individuals. Adoptive transfer of CII-specific CD4+CD28−OX40+ T cells remarkably aggravated arthritic development and joint pathology in CIA mice. Moreover, OX40 blockade significantly reduced the proinflammatory responses and ameliorated arthritis development.ConclusionsOX40 acts as an alternative costimulator of CD4+CD28− T cells and plays a pathogenic role in autoimmune arthritic development, suggesting that it is a potential target for immunomodulatory therapy of RA.