The off-target effects of AID in carcinogenesis

Activation-induced cytidine deaminase (AID) plays a crucial role in promoting B cell diversification through somatic hypermutation (SHM) and class switch recombination (CSR). While AID is primarily associated with the physiological function of humoral immune response, it has also been linked to the initiation and progression of lymphomas. Abnormalities in AID have been shown to disrupt gene networks and signaling pathways in both B-cell and T-cell lineage lymphoblastic leukemia, although the full extent of its role in carcinogenesis remains unclear. This review proposes an alternative role for AID and explores its off-target effects in regulating tumorigenesis. In this review, we first provide an overview of the physiological function of AID and its regulation. AID plays a crucial role in promoting B cell diversification through SHM and CSR. We then discuss the off-target effects of AID, which includes inducing mutations of non-Igs, epigenetic modification, and the alternative role as a cofactor. We also explore the networks that keep AID in line. Furthermore, we summarize the off-target effects of AID in autoimmune diseases and hematological neoplasms. Finally, we assess the off-target effects of AID in solid tumors. The primary focus of this review is to understand how and when AID targets specific gene loci and how this affects carcinogenesis. Overall, this review aims to provide a comprehensive understanding of the physiological and off-target effects of AID, which will contribute to the development of novel therapeutic strategies for autoimmune diseases, hematological neoplasms, and solid tumors

microRNA-7: A critical sensitizer for TRAIL sensitivity in glioblastoma cells

TRAIL (TNF-related apoptosis-inducing ligand) is a promising anticancer agent because of its tumor-specifc apoptosis inducer activity without affecting normal cells. MicroRNAs (miRNAs) emerge as important regulators of cell viability. Our recent studies showed that miR-7 is a potential sensitizer for TRAIL-induced apoptosis in glioblastoma (GBM) cells, and XIAP is a critical gene in the apoptotic process as a direct downstream gene of miR-7. Additionally, this regulatory axis could also exert in other types of tumor cells. More importantly, we confirmed that co-delivery of sTRAIL and tumor suppressor miR-7 by MSCs leads to synergistic cancer killing effect. Thus, miR-7 has been demonstrated to be a critical sensitizer for TRAIL-induced apoptosis through regulating XIAP and highlights a novel therapeutic strategy for the treatment of GBM

Increased levels of soluble CD226 in sera accompanied by decreased membrane CD226 expression on peripheral blood mononuclear cells from cancer patients

<p>Abstract</p> <p>Background</p> <p>As a cellular membrane triggering receptor, CD226 is involved in the NK cell- or CTL-mediated lysis of tumor cells of different origin, including freshly isolated tumor cells and tumor cell lines. Here, we evaluated soluble CD226 (sCD226) levels in sera, and membrane CD226 (mCD226) expression on peripheral blood mononuclear cells (PBMC) from cancer patients as well as normal subjects, and demonstrated the possible function and origin of the altered sCD226, which may provide useful information for understanding the mechanisms of tumor escape and for immunodiagnosis and immunotherapy.</p> <p>Results</p> <p>Soluble CD226 levels in serum samples from cancer patients were significantly higher than those in healthy individuals (<it>P </it>< 0.001), while cancer patients exhibited lower PBMC mCD226 expression than healthy individuals (<it>P </it>< 0.001). CD226-Fc fusion protein could significantly inhibit the cytotoxicity of NK cells against K562 cells in a dose-dependent manner. Furthermore, three kinds of protease inhibitors could notably increase mCD226 expression on PMA-stimulated PBMCs and Jurkat cells with a decrease in the sCD226 level in the cell culture supernatant.</p> <p>Conclusion</p> <p>These findings suggest that sCD226 might be shed from cell membranes by certain proteases, and, further, sCD226 may be used as a predictor for monitoring cancer, and more important, a possible immunotherapy target, which may be useful in clinical application.</p

MicroRNA Let-7a Inhibits Proliferation of Human Prostate Cancer Cells In Vitro and In Vivo by Targeting E2F2 and CCND2

Previous work has shown reduced expression levels of let-7 in lung tumors. But little is known about the expression or mechanisms of let-7a in prostate cancer. In this study, we used in vitro and in vivo approaches to investigate whether E2F2 and CCND2 are direct targets of let-7a, and if let-7a acts as a tumor suppressor in prostate cancer by down-regulating E2F2 and CCND2.Findings Real-time RT-PCR demonstrated that decreased levels of let-7a are present in resected prostate cancer samples and prostate cancer cell lines. Cellular proliferation was inhibited in PC3 cells and LNCaP cells after transfection with let-7a. Cell cycle analysis showed that let-7a induced cell cycle arrest at the G1/S phase. A dual-luciferase reporter assay demonstrated that the 3′UTR of E2F2 and CCND2 were directly bound to let-7a and western blotting analysis further indicated that let-7a down-regulated the expression of E2F2 and CCND2. Our xenograft models of prostate cancer confirmed the capability of let-7a to inhibit prostate tumor development in vivo.These findings help to unravel the anti-proliferative mechanisms of let-7a in prostate cancer. Let-7a may also be novel therapeutic candidate for prostate cancer given its ability to induce cell-cycle arrest and inhibit cell growth, especially in hormone-refractory prostate cancer

The Genetic Polymorphisms of HLA Are Strongly Correlated with the Disease Severity after Hantaan Virus Infection in the Chinese Han Population

The polymorphism of human leukocyte antigen (HLA), which is a genetic factor that influences the progression of hemorrhagic fever with renal syndrome (HFRS) after Hantaan virus (HTNV) infection, was incompletely understood. In this case-control study, 76 HFRS patients and 370 healthy controls of the Chinese Han population were typed for the HLA-A, -B, and -DRB1 loci. The general variation at the HLA-DRB1 locus was associated with the onset of HFRS (P<0.05). The increasing frequencies of HLA-DRB1*09 and HLA-B*46-DRB1*09 in HFRS patients were observed as reproducing a previous study. Moreover, the HLA-B*51-DRB1*09 was susceptible to HFRS (P=0.037; OR =3.62; 95% CI: 1.00–13.18). The increasing frequencies of HLA-B*46, HLA-B*46-DRB1*09, and HLA-B*51-DRB1*09 were observed almost in severe/critical HFRS patients. The mean level of maximum serum creatinine was higher in HLA-B*46-DRB1*09 (P=0.011), HLA-B*51-DRB1*09 (P=0.041), or HLA-B*46 (P=0.011) positive patients than that in the negative patients. These findings suggest that the allele HLA-B*46 and haplotypes HLA-B*46-DRB1*09 and HLA-B*51-DRB1*09 in patients could contribute to a more severe degree of HFRS and more serious kidney injury, which improve our understanding of the HLA polymorphism for a different outcome of HTNV infection

Production and characterization of a recombinant single-chain antibody against Hantaan virus envelop glycoprotein

Hantaan virus (HTNV) is the type of Hantavirus causing hemorrhagic fever with renal syndrome, for which no specific therapeutics are available so far. Cell type-specific internalizing antibodies can be used to deliver therapeutics intracellularly to target cell and thus, have potential application in anti-HTNV infection. To achieve intracellular delivery of therapeutics, it is necessary to obtain antibodies that demonstrate sufficient cell type-specific binding, internalizing, and desired cellular trafficking. Here, we describe the prokaryotic expression, affinity purification, and functional testing of a single-chain Fv antibody fragment (scFv) against HTNV envelop glycoprotein (GP), an HTNV-specific antigen normally located on the membranes of HTNV-infected cells. This HTNV GP-targeting antibody, scFv3G1, was produced in the cytoplasm of Escherichia coli cells as a soluble protein and was purified by immobilized metal affinity chromatography. The purified scFv possessed a high specific antigen-binding activity to HTNV GP and HTNV-infected Vero E6 cells and could be internalized into HTNV-infected cells probably through the clathrin-dependent endocytosis pathways similar to that observed with transferrin. Our results showed that the E. coli-produced scFv had potential applications in targeted and intracellular delivery of therapeutics against HTNV infections

MICA/B expression is inhibited by unfolded protein response and associated with poor prognosis in human hepatocellular carcinoma

BackgroundMICA/B are major ligands for NK cell activating receptor NKG2D and previous studies showed that the serum level of soluble MICA (sMICA) is an independent prognostic factor for advanced human hepatocellular carcinoma. However, the correlation between cellular MICA/B expression pattern and human hepatocellular carcinoma progression has not been well explored. The unfolded protein response is one of the main causes of resistance to chemotherapy and radiotherapy in tumor cells. However, whether the UPR in HCC could regulate the expression levels of MICA/B and affect the sensitivity of HCC cells to NK cell cytolysis has not been established yet.MethodsMICA/B expression pattern was evaluated by immunohistochemistry and Kaplan-Meier survival analysis was done to explore the relationship between MICA/B expression level and patient survival. The protein and mRNA expression levels of MICA/B in SMMC7721 and HepG2 cells treated by tunicamycin were evaluated by flow cytometry, Western Blot and RT-PCR. The cytotoxicity analysis was performed with the CytoTox 96 Non-Radioactive LDH Cytotoxicity Assay.ResultsMICA/B was highly expressed in human hepatocellular carcinoma and the expression level was significantly and negatively associated with tumor-node metastasis (TNM) stages. Patients with low level of MICA/B expression showed a trend of shorter survival time. The unfolded protein response (UPR) downregulated the expression of MICA/B. This decreased protein expression occurred via post-transcriptional regulation and was associated with proteasomal degradation. Moreover, decreased expression level of MICA/B led to the attenuated sensitivity of human HCC to NK cell cytotoxicity.ConclusionThese new findings of the connection of MICA/B, UPR and NK cells may represent a new concrete theory of NK cell regulation in HCC, and suggest that targeting this novel NK cell-associated immune evasion pathway may be meaningful in treating patients with HCC.Electronic supplementary materialThe online version of this article (doi:10.1186/s13046-014-0076-7) contains supplementary material, which is available to authorized users

A fast algorithm for sparse signal recovery via fraction function

Abstract In this article, a fast algorithm is studied to recover the sparse signals. It can be regarded as an extension of the parameterized fast iterative shrinkage‐thresholding algorithm from convex optimization to nonconvex optimization. Numerical results show that the proposed fast algorithm is efficient and fast in recovering the sparse signals