分类： 生物学 >> 生物物理学 提交时间： 2016-05-15
摘要： Background: Carcinoembryonic antigen (CEA) is a protein commonly found in human serum, with elevated CEA levels being linked to the progression of a wide range of tumors. It is currently used as a biomarker for malign tumors such as lung cancer and colorectal cancer [Urol Oncol: Semin Orig Invest 352: 644-648, 2013 and Lung Cancer 80: 45-49, 2013]. However, due to its low specificity in clinical applications, CEA can be used for monitoring only, rather than tumor diagnosis. The function of many glycoproteins is critically dependent on their glycosylation pattern, which in turn has the potential to serve in tumor detection. However, little is known about the detailed glycan patterns of CEA. Methods: To determine these patterns, we isolated and purified CEA proteins from human tumor tissues using immunoaffinity chromatography. The glycan patterns of CEA were then analyzed using a Matrix-Assisted Laser Desorption/Ionization-Time of Flight-Mass Spectrometry3 (MALDI-TOF-MS3) approach. Results: We identified 61 glycoforms in tumor tissue, where CEA is upregulated. These glycosylation entities were identified as bi-antennary, tri-antennary and tetra-antennary structures carrying sialic acid and fucose residues, and include a multitude of glycans previously not reported for CEA. Conclusion: Our findings should facilitate a more precise tumor prediction than currently possible, ultimately resulting in improved tumor diagnosis and treatment.
分类： 生物学 >> 生物物理学 提交时间： 2016-05-12
Deng, Zaian
Zhang, Yaou
Cai, Guoping
Deng, Zaian
Li, Yaojun
Fan, Jia
Wang, Guohui
Shen, Haifa
Ferrari, Mauro
Hu, Tony Y.
Deng, Zaian
Zhang, Yaou
Cai, Guoping
Li, Yan
Shen, Haifa
Hu, Tony Y.
Ferrari, Mauro
摘要： Tumor-resident proteases (TRPs) are regarded as informative biomarkers for staging cancer progression and evaluating therapeutic efficacy. Currently in the clinic, measurement of TRP is dependent on invasive biopsies, limiting their usefulness as monitoring tools. Here we identified circulating peptides naturally produced by TRPs, and evaluated their potential to monitor the efficacy of anti-tumor treatments. We established a mouse model for ovarian cancer development and treatment by orthotopic implantation of the human drug-resistant ovarian cancer cell line HeyA8-MDR, followed by porous silicon particle-or multistage vector (MSV) -enabled EphA2 siRNA therapy. Immunohistochemistry staining of tumor tissue revealed decreased expression of matrix metallopeptidase 9 (MMP-9) in mice exhibiting positive responses to MSV-EphA2 siRNA treatment. We demonstrated, via an ex vivo proteolysis assay, that C3f peptides can act as substrates of MMP-9, which cleaves C3f at L-1311-L-1312 into two peptides (SSATTFRL and LWENGNLLR). Importantly, we showed that these two C3f-derived fragments detected in serum were primarily generated by tumor-resident, but not blood-circulating, MMP-9. Our results suggested that the presence of the circulating fragments specially derived from the localized cleavage in tumor microenvironment can be used to evaluate therapeutic efficacy of anti-cancer treatment, assessed through a relatively noninvasive and user-friendly proteomics approach.
分类： 生物学 >> 生物物理学 提交时间： 2016-05-12
Yuan, Shanshan
Zhang, Yang
Liu, Yalei
Yu, Nan
Zhang, Hong
Lu, Guizhi
Gao, Yanming
Gao, Ying
Guo, Xiaohui
Li, Qianqian
Huang, Chuncui
Wu, Hongmei
Li, Yan
摘要： Objective: Sera of Hashimoto's thyroiditis (HT) patients are known to exhibit elevated levels of anti-thyroglobulin IgG (TgAb IgG). Therefore, TgAb IgG represents a hallmark of this debilitating autoimmune disease. The aim of our study was to investigate the differential expression of specific glycosylation patterns of TgAb IgG from HT patients and healthy blood donors. Methods: HT patients (n = 32) were divided into two subgroups, medium level group (mHT, n = 15) and high level group (hHT, n = 17), according to the serum levels of TgAb detected by electrochemiluminescence immunoassay. TgAb IgG was purified by affinity chromatography from the sera of the HT group and control group (n = 15). MALDI-QIT-TOF-MS/MS spectrometry was performed to identify the glycosylation profiles of purified TgAb IgG. Lectin microarray technology was used to compare the abundance of different glycans found on TgAb IgG between HT patients and controls, and between the mHT and hHT groups. Results: The results by MALDI-QIT-TOF-MS/MS showed that the glycosylation profiles of TgAb IgG were similar between the mHT, hHT, and control groups. Furthermore, the lectin microarray showed that compared to the control group (all P < .001), there were higher levels present of (1) mannose (detected as lectin LCA, VFA, and MNA-M); (2) terminal sialic acid (detected as SNA-I and PSA); (3) core fucose (detected as LcH); and (4) Gal(beta 1-4) GlcNAc(beta 1-2) Man glycans (detected as PHA-L) on TgAb IgG from the HT group. A similar trend was observed between the hHT and mHT group, with elevated levels of mannose, terminal sialic acid, core fucose, and Gal(beta 1-4) GlcNAc(< 12) Man glycans on TgAb IgG found in the hHT group compared with the mHT group (all P < .05). Conclusions: TgAb IgG of HT patients exhibits higher glycosylation levels than those observed for TgAb IgG of healthy controls. Our results provide new clues for exploring the role of TgAb in the pathogenesis of HT.
分类： 生物学 >> 生物物理学 提交时间： 2016-05-11
Li, Yan
Shah, Punit
De Marzo, Angelo M.
Chan, Daniel W.
Zhang, Hui
Van Eyk, Jennifer E.
Li, Yan
Lo, Qianqian
Van Eyk, Jennifer E.
摘要： Glycosylation is one of the most common protein modifications. Each glycoprotein can be glycosylated at multiple glycosites, and each glycosites can be modified by different glycans. Due to this heterogeneity of glycosylation, it has proven difficult to study the structure-function relationship of specific glycans and their affected glycoproteins. Here, we report a novel method for rapid and quantitative identification of glycoproteins containing specific glycans. Lectin affinity isolations are followed by chemical immobilization of the captured glycopeptides, allowing the identification of glycoproteins containing specific glycans by subsequent mass spectrometry. The application of the method should be useful to facilitate our understanding of how changes in glycan associate with diseases, and to discover novel glycoproteins with certain glycans that could serve as biomarkers or therapeutic targets.
分类： 生物学 >> 生物物理学 >> 生物物理、生物化学与分子生物学 提交时间： 2016-05-11
摘要： Age-related memory impairment (AMI) is a phenomenon observed from invertebrates to human. Memory extinction is proposed to be an active inhibitory modification of memory, however, whether extinction is affected in aging animals remains to be elucidated. Employing a modified paradigm for studying memory extinction in fruit flies, we found that only the stable, but not the labile memory component was suppressed by extinction, thus effectively resulting in higher memory loss in aging flies. Strikingly, young flies were able to fully restore the stable memory component 3 h post extinction, while aging flies failed to do so. In conclusion, our findings reveal that both accelerated extinction and impaired restoration contribute to memory impairment in aging animals. (C) 2015 Elsevier Inc. All rights reserved.
分类： 生物学 >> 生物物理学 >> 衰老生物学 提交时间： 2016-05-05
摘要： microRNA-9 (miR-9) is highly expressed in the nervous system across species and plays essential roles in neurogenesis and axon growth; however, little is known about the mechanisms that link miR-9 with dendrite growth. Using an in vivo model of Drosophila class I dendrite arborization (da) neurons, we show that miR-9a, a Drosophila homolog of mammalian miR-9, downregulates the cadherin protein Flamingo (Fmi) thereby attenuating dendrite development in a non-cell autonomous manner. In miR-9a knockout mutants, the dendrite length of a sensory neuron ddaE was significantly increased. Intriguingly, miR-9a is specifically expressed in epithelial cells but not in neurons, thus the expression of epithelial but not neuronal Fmi is greatly elevated in miR-9a mutants. In contrast, overexpression of Fmi in the neuron resulted in a reduction in dendrite growth, suggesting that neuronal Fmi plays a suppressive role in dendrite growth, and that increased epithelial Fmi might promote dendrite growth by competitively binding to neuronal Fmi. Fmi has been proposed as a G protein-coupled receptor (GPCR), we find that neuronal G protein Gq (Gq), but not Go, may function downstream of Fmi to negatively regulate dendrite growth. Taken together, our results reveal a novel function of miR-9a in dendrite morphogenesis. Moreover, we suggest that Gq might mediate the intercellular signal of Fmi in neurons to suppress dendrite growth. Our findings provide novel insights into the complex regulatory mechanisms of microRNAs in dendrite development, and further reveal the interplay between the different components of Fmi, functioning in cadherin adhesion and GPCR signalling. (c) 2015 Wiley Periodicals, Inc. Develop Neurobiol 76: 225-237, 2016
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