[Show abstract][Hide abstract] ABSTRACT: Epigenetic silence in cancer frequently altered signal-transduction pathways during the early stages of tumor development. Recent progress in the field of cancer epigenetics has led to new opportunities for diagnosis and treatment of cancer. We previously demonstrated that novel identified nuclear factor MARVELD1 was widely expressed in human tissues, but down-regulated by promoter methylation in multiple cancers. This study was carried out to determine the biological and clinical significance of MARVELD1 gene silencing in lung cancer. Here, we found the reduced MARVELD1 expression significantly correlated with diagnostic histopathology and malignant degree of lung cancers. DNA hypermethylation and histone deacetylation synergistically inactivated MARVELD1 gene in lung cancer cells. Moreover, MARVELD1 modulated the efficiency of nonsense-mediated mRNA decay (NMD) through interaction with NMD core factor SMG1. The decreased MARVELD1 level in lung cancer reduces NMD efficiency through diminishing the association between NMD complex component UPF1/SMG1 and premature termination codons containing mRNA (PTC-mRNA). The results suggested that MARVELD1 silencing is an appealing diagnostic biomarker for lung cancer and epigenetic silencing of MARVELD1 gene links with the regulatory mechanism of NMD pathway in lung cancer, which may be required for tumorigenesis.
[Show abstract][Hide abstract] ABSTRACT: Apoptosis-inducing factor (AIF) plays a crucial role in caspase-independent programmed cell death by triggering chromatin condensation and DNA fragmentation. Therefore, it might be involved in cell homeostasis and tumor development. In this study, we report significant AIF downregulation in the majority of renal cell carcinomas (RCC). In a group of RCC specimens, 84% (43 out of 51) had AIF downregulation by immunohistochemistry stain. Additional 10 kidney tumors, including an oxyphilic adenoma, also had significant AIF downregulation by Northern blot analysis. The mechanisms of the AIF downregulation included both AIF deletion and its promoter methylation. Forced expression of AIF in RCC cell lines induced massive apoptosis. Further analysis revealed that AIF interacted with STK3, a known regulator of apoptosis, and enhanced its phosphorylation at Thr180. These results suggest that AIF downregulation is a common event in kidney tumor development. AIF loss may lead to decreased STK3 activity, defective apoptosis and malignant transformation.
PLoS ONE 01/2014; 9(7):e100824. · 3.53 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: We report bovine serum albumin (BSA)-boronic acid (BA) conjugates as lectin mimetics and their glyco-capturing capacity. The BSA-BA conjugates were synthesized by amidation of carboxylic acid groups in BSA with aminophenyl boronic acid in the presence of EDC, and were characterized by Alizarin Red S (ARS) assay and SDS-PAGE gel. The BSA-BA conjugates were immobilized onto maleimide-functionalized silica beads and their sugar capturing capacity and specificity were confirmed by ARS displacement assay. Further, surface plasmon resonance (SPR) analysis of the glyco-capturing activity of the BSA-BA conjugates was conducted by immobilizing BSA-BA onto SPR gold chip. Overall, we demonstrated a BSA-BA-based lectin mimetics for glyco-capturing applications. These lectin mimetics are expected to provide an important tool for glycomics and biosensor research and applications.
Biochemical and Biophysical Research Communications 12/2013; · 2.28 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Aberrant changes in specific glycans have been shown to be associated with immunosurveillance, tumorigenesis, tumor progression and metastasis. In this study, the N-glycan profiling of membrane proteins from human breast cancer cell lines and tissues was detected using modified DNA sequencer-assisted fluorophore-assisted carbohydrate electrophoresis (DSA-FACE). The N-glycan profiles of membrane proteins were analyzed from 7 breast cancer cell lines and MCF 10A, as well as from 100 pairs of breast cancer and corresponding adjacent tissues. The results showed that, compared with the matched adjacent normal tissue samples, two biantennary N-glycans (NA2 and NA2FB) were significantly decreased (p <0.0001) in the breast cancer tissue samples, while the triantennary glycan (NA3FB) and a high-mannose glycan (M8) were dramatically increased (p = 0.001 and p <0.0001, respectively). Moreover, the alterations in these specific N-glycans occurred through the oncogenesis and progression of breast cancer. These results suggested that the modified method based on DSA-FACE is a high-throughput detection technology that is suited for analyzing cell surface N-glycans. These cell surface-specific N-glycans may be helpful in recognizing the mechanisms of tumor cell immunologic escape and could be potential targets for new breast cancer drugs.
PLoS ONE 01/2013; 8(8):e72704. · 3.53 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Glycopolymers as multivalent clusters of carbohydrate derivatives have been proven effective tools in the study of carbohydrate-based biological processes and have shown great potential in biomedical applications. It has been found that the shape and size of glycopolymers, as well as the density and relative positioning of their glycan appendages, are very important regarding their effectiveness in bio-interactions. Recently, a variety of chain-end functionalized polymers have been explored for the preparation of structurally well-defined glycopolymers that have potential protein modification and microarray fabrication applications. This review summarizes recent advances in the synthesis and biomedical applications of chain-end functionalized glycopolymers.
[Show abstract][Hide abstract] ABSTRACT: Recent emergences of glycobiology, glycotechnology and glycomics have been clarifying enormous roles of carbohydrates in biological recognition systems. For example, cell surface carbohydrates existing as glycoconjugates (glycolipids, glycoproteins and proteoglycans) play crucial roles in cell-cell communication, cell proliferation and differentiation, tumor metastasis, inflammatory response or viral infection. In particular, sialic acids (SAs) existing as terminal residues in carbohydrate chains on cell surface are involved in signal recognition and adhesion to ligands, antibodies, enzymes and microbes. In addition, plasma free SAs and sialoglycans have shown great potential for disease biomarker discovery. Therefore, the development of efficient analytical methods for structural and functional studies of SAs and sialylglycans are very important and highly demanded. The problems of SAs and sialylglycans analysis are vanishingly small sample amount, complicated and unstable structures, and complex mixtures. Nevertheless, in the past decade, mass spectrometry in combination with chemical derivatization and modern separation methodologies has become a powerful and versatile technique for structural analysis of SAs and sialylglycans. This review summarizes these recent advances in glycomic studies on SAs and sialylglycans. Specially, derivatization and capturing of SAs and sialylglycans combined with mass spectrometry analysis are highlighted.
Journal of proteomics 04/2012; 75(11):3098-112. · 5.07 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: We have previously found that expression of MARVELD1 was remarkably downregulated in multiple tumor tissues, but unclear in hepatocellular carcinoma (HCC) and its function has not been explored yet. In the present study, to uncover the underlying mechanism of MARVELD1 in the pathogenesis and development of HCC, we investigated the expression pattern of MARVELD1 and its effect on tumor proliferation in HCC. The results indicated the frequent downregulation of MARVELD1 in clinic samples and cell lines of HCC resulted from promoter methylation, as well as genetic deletion. Furthermore, treatment of MARVELD1 unexpressing Hep3B2.1-7 and PLC/PRF/5 cells with the demethylating agent 5-aza-2' deoxycytidine restored its expression. Overexpression of MARVELD1 suppressed the proliferation of HCC cells in vitro and in vivo, whereas downregulation of endogenous MARVELD1 by shRNAs significantly enhanced these characters. MARVELD1 overexpression could enhance chemosensitivity of HCC cells to epirubicin and 10-hydroxycamptothecin. Corresponding to these results, the expression of p-ERK1/2 and cyclin D1 were decreased, whereas p16 and p53 were increased in MARVELD1-transfected cells. We also demonstrated that knockdown of MARVELD1 resulted in upregulation of p-ERK1/2 and cyclin D1, and downregulation of p16 and p53. Moreover, the effect of the decreased cell growth rate was significantly reversed when MARVELD1-overexpressing cells were trasfected with p53 or p16 siRNA. Our findings suggest that MARVELD1 is a tumor suppressor by negatively regulating proliferation, tumor growth and chemosensitivity of HCC cells via increasing p53 and p16 in vitro and in vivo. MARVELD1 may be a potential target for HCC therapy.
Cancer Science 02/2012; 103(4):716-22. · 3.48 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: protein glycosylation varies with the physiological and pathological status of the cell. Consequently, analysis of protein-linked glycans has growing importance both in basic glycobiological research and as a potential tool for monitoring the physiological state in humans.
a total of 265 healthy northern Chinese men and women were grouped by age and gender. The mean age in males and females was similar.
the study is aimed to evaluate the effects of the age and gender on the human serum N-glycans profiles in the clinical diagnose of ageing and disease.
the 265 human serum N-glycan profiles were obtained by DNA sequencer-assisted fluorophore-assisted carbohydrate electrophoresis. Comparison of N-glycan profiles was carried out among the different genders and age groups and the data were analysed with the GeneMapper software.
age-related changes in the three N-glycan structures (NGA2F, NGA2FB and NA2F) were observed. Interestingly, fucosylation of N-glycans was significantly different (P < 0.0001) between men and women: more core-α-1,6-fucosylated glycans were detected in women, whereas more branching-α-1,3-fucosylated N-glycans were seen in men.
the N-glycome profile in serum is gender and age dependent. This should be taken into consideration in the development of serum glycome markers.
Age and Ageing 09/2011; 40(5):568-75. · 3.82 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Lipoprotein receptor-related protein 1 B (LRP1B) is one of gigatic receptor subgroup members of lipoprotein receptor family. LRP1B encodes a huge transcript of 16.5 kb. There were difficulties for analysis of LRP1B function due to its huge transcript. In order to study the relation of LRP1B with tumor metastasis, the expression of LRP1B was blocked specially by using RNAi. According to the evaluated standard of the siRNAs and mRNA secondary structure at these target regions, out of the 1 100 candidates, 6 superior ones which locate at different regions of mRNA were selected during designing siRNA sequences. For these 6 targets, shRNA-pSilencer 4.1 recombinant were constructed and transfected into HEK 293 cells. The silencing effects of each siRNA were quantitatively assessed by Semi-Quantitative RT-PCR. It was found that 5 of these 6 shRNA-pSilencer4.1 recombinant could effectively silence the targeted gene LRP1B (>50%). Meanwhile several monoclonal cells, in which the expression of LRP1B was almost completely blocked, had been obtained. The results showed that the method for selecting siRNA, which integrates with mRNA secondary structure, provides a feasible and efficient approach on the design of siRNA of huge gene transcript.