Browsing by Author "Tzou, Shey-Cherng"

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A regularly spaced and self-revealing protein ladder for anti-tag Western blot analysis
(2012-12-01)
Kao, Chien-Han
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Cheng, Chiu-Min
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Chuang, Kuo-Hsiang
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Chuang, Chih-Hung
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Tzou, Shey-Cherng
We designed a protein ladder (hereafter referred to as "Mega-tag") that contains 14 of the most commonly used epitope tags fused to molecular weight markers. The Mega-tag ladder can be simultaneously visualized when anti-tag antibodies are used to detect epitope-tagged recombinant proteins in Western blots. The logarithm of molecular weights and relative mobility of the Mega-tag protein ladder are highly correlated (R-2 = 0.997 +/- 0.00232), indicating that the dye-free Mega-tag protein ladder is accurate. It can also serve as a positive control for anti-epitope tag immunoblots. The Mega-tag protein ladder should provide a convenient and precise tool for Western blot analysis. (c) 2012 Elsevier Inc. All rights reserved.
A site-moiety map and virtual screening approach for discovery of novel 5-LOX inhibitors
(2020-06-29)
Hsu, Kai-Cheng
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HuangFu, Wei-Chun
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Lin, Tony Eight
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Chao, Min-Wu
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Sung, Tzu-Ying
The immune system works in conjunction with inflammation. Excessive inflammation underlies various human diseases, such as asthma, diabetes and heart disease. Previous studies found that 5-lipoxygenase (5-LOX) plays a crucial role in metabolizing arachidonic acid into inflammatory mediators and is a potential therapeutic target. In this study, we performed an in silico approach to establish a site-moiety map (SiMMap) to screen for new 5-LOX inhibitors. The map is composed of several anchors that contain key residues, moiety preferences, and their interaction types (i.e., electrostatic (E), hydrogen-bonding (H), and van der Waals (V) interactions) within the catalytic site. In total, we identified one EH, one H, and five V anchors, within the 5-LOX catalytic site. Based on the SiMMap, three 5-LOX inhibitors (YS1, YS2, and YS3) were identified. An enzyme-based assay validated inhibitory activity of YS1, YS2, and YS3 against 5-LOX with an IC50 value of 2.7, 4.2, and 5.3 mu M, respectively. All three inhibitors significantly decrease LPS-induced TNF-alpha and IL-6 production, which suggests its potential use an anti-inflammatory agent. In addition, the identified 5-LOX inhibitors contain a novel scaffold. The discovery of these inhibitors presents an opportunity for designing specific anti-inflammatory drugs.
Blockade of ITGA2 Induces Apoptosis and Inhibits Cell Migration in Gastric Cancer
(2018-05-01)
Chuang, Yu-Chang
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Wu, Hsin-Yi
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Lin, Yu-Ling
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Tzou, Shey-Cherng
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Chuang, Cheng-Hsun
Background: Gastric cancer is currently the fourth leading cause of cancer-related death worldwide. Gastric cancer is often diagnosed at advanced stages and the outcome of the treatment is often poor. Therefore, identifying new therapeutic targets for this cancer is urgently needed. Integrin alpha 2 (ITGA2) subunit and the beta 1 subunit form a heterodimer for a transmembrane receptor for extracellular matrix, is an important molecule involved in tumor cell proliferation, survival and migration. Integrin alpha 2 beta 1 is over-expressed on a variety of cancer cells, but is low or absent in most normal organs and resting endothelial cells. Results: In this report, we assessed the ITGA2 as the potential therapeutic target with the bioinformatics tools from the TCGA dataset in which composed of 375 gastric cancer tissues and 32 gastric normal tissues. According to the information from the Cancer Cell Line Encyclopedia (CCLE) database, the AGS cell line with ITGA2 high expression and the SUN-1 cell line with low expression were chosen for the further investigation. Interestingly, the anti-ITGA2 antibody (at 3 mu g/ml) inhibited approximately 50% survival of the AGS cells (over-expressed ITGA2), but had no effect in SNU-1 cells (ITGA2 negative). The extents of antibody-mediated cancer inhibition positively correlated with the expression levels of the ITGA2. We further showed that the anti-ITGA2 antibody induced apoptosis by upregulating the RhoA-p38 MAPK signaling to promote the expressions of Bim, Apaf-1 and Caspase-9, whereas the expressions of Ras and Bax/Bcl-2 were not affected. Moreover, blocking ITGA2 by the specific antibody at lower doses also inhibited cell migration of gastric cancer cells. Blockade of ITGA2 by a specific antibody down-regulated the expression of N-WASP, PAK and LIMK to impede actin organization and cell migration of gastric cancer cells. Conclusions: Here, we showed that the mRNA expression levels of ITGA2 comparing to normal tissues significantly increased. In addition, the results revealed that targeting integrin alpha 2 subunit by antibodies did not only inhibit cell migration, but also induce apoptosis effect on gastric cancer cells. Interestingly, higher expression level of ITGA2 led to significant effects on apoptosis progression during anti-ITGA2 antibody treatment, which indicated that ITGA2 expression levels directly correlate with their functionality. Our findings suggest that ITGA2 is a potential therapeutic target for gastric cancer.
Development of a Gd(III)-Based Receptor-Induced Magnetization Enhancement (RIME) Contrast Agent for beta-Glucuronidase Activity Profiling
(2012-11-19)
Chen, Shih-Hsien
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Kuo, Yu-Ting
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Singh, Gyan
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Cheng, Tian-Lu
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Su, Yu-Zheng
beta-Glucuronidase is a key lysosomal enzyme and is often overexpressed in necrotic tumor masses. We report here the synthesis of a pro receptor induced magnetization enhancement (pro RIME) magnetic resonance imaging (MRI) contrast agent ([Gd(DOTA-FP beta Gu)]) for molecular imaging of beta-glucuronidase activity in tumor tissues. The contrast agent consists of two parts, a gadolinium complex and a beta-glucuronidase substrate (beta-D-glucopyranuronic acid). The binding association constant (K-A) of [Gd(DOTA-FP beta Gu)] is 7.42 X 10(2), which is significantly lower than that of a commercially available MS-325 (K-A = 3.0 x 10(4)) RIME contrast agent. The low K-A value of [Gd(DOTA-FP beta Gu)] is due to the pendant beta-D-glucopyranuronic acid moiety. Therefore, [Gd(DOTA-FP beta Gu)] can be used for detection of beta-glucuronidase through RIME modulation. The detail mechanism of enzymatic activation of [Gd(DOTA-FP beta Gu)] was elucidated by LC-MS. The kinetics of beta-glucuronidase catalyzed hydrolysis of [Eu(DOTA-FP beta Gu)] at pH 7.4 best fit the Miechalis-Menten kinetic mode with K-m = 1.38 mM, K-cat = 3.76 x 10(3), and k(cat)/K-m = 2.72 x 10(3) M-1 s(-1). The low K-m value indicates high affinity of beta-glucuronidase for [Gd(DOTA-FP beta Gu)] FP beta Gu) at physiological pH. Relaxometric studies revealed that T-1 relaxivity of [Gd(DOTA-FP beta Gu)] changes in response to the concentration of beta-glucuronidase. Consistent with the relaxometric studies, [Gd(DOTA-FP beta Gu)] showed significant change in MR image signal in the presence of beta-glucuronidase and HSA. In vitro and in vivo MR images demonstrated appreciable differences in signal enhancement in the cell lines and tumor xenografts in accordance to their expression levels of beta-glucuronidase. [GRAPHICS] .
Development of a novel thermal-sensitive multifunctional liposome with antibody conjugation to target EGFR-expressing tumors
(2019-01-01)
Liu, Kuan-Chieh
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Arivajiagane, Arundhathi
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Wu, Shang-Jung
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Tzou, Shey-Cherng
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Chen, Chiao-Yun
A novel EGFR-targeting, thermal-sensitive multifunctional liposome (TSML) was developed based on manganese-doped magnetismengineered iron oxide nanoparticles (MnMEIOs) and gold nanorods (AuNRs) for efficient photothermal therapy and magnetic resonance (MR) imaging. An Erbitux-conjugated TSML (Erb-TSML) was encapsulated with doxorubicin and gold nanorods conjugated with manganese-doped magnetism-engineered iron oxide nanoparticles, for theranostic applications of EGFR-positive tumors. The Erb-TSML selectively targeted EGFRpositive tumors and promoted tumor destruction by laser activation. Using confocal microscopy, MR and optical imaging, we demonstrated that Erb-TSML specifically bound to A431 tumor cells. No signs of major morphological damages to the normal tissues were observed in mice treated with Erb-TSMLand laser, indicating this theranostic platform protected heart against doxorubicin-induced toxicity to normal tissues. These results indicate that the Erb-TSML may be a promising diagnostic and therapeutic platform for EGFR-overexpressing tumors. (C) 2018 Elsevier Inc. All rights reserved.
Development of an inflammatory tissue-selective chimeric TNF receptor
(2019-01-01)
Lee, Chia-Jung
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Wang, Chao-Ching
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Chen, Michael
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Chuang, Kuo-Hsiang
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Cheng, Tian-Lu
Background: Inhibiting TNF-alpha is an effective therapy for inflammatory diseases such as rheumatoid arthritis. However, systemic, nondiscriminatory neutralization of TNF-alpha is associated with considerable adverse effects. Methods: Here, we developed a trimeric chimeric TNF receptor by linking an N-terminal mouse Acrp30 trimerization domain and an MMP-2/9 substrate sequence to the mouse extracellular domain of TNF receptor 2 followed by a C-terminal mouse tetranectin coiled-coil domain (mouse Acrp-MMP-TNFR-Tn). Results: Here, we show that the Acrp30 trimerization domain inhibited the binding activity of TNFR, possibly by closing the binding site of the trimeric receptor. Cleavage of the substrate sequence by MMP-9, an enzyme highly expressed in inflammatory sites, restored the binding activity of the mouse TNF receptor. We also constructed a recombinant human chimeric TNF receptor (human Acrp-MMP-TNFR-Tn) in which an MMP-13 substrate sequence was used to link the human Acrp and the human TNF receptor 2. Human Acrp-MMP-TNFR-Tn showed reduced binding activity, and MMP-13 digestion recovered its binding activity with TNF-alpha. Conclusion: Acrp-masked chimeric TNF receptors may be able to be used for inflammatory tissue-selective neutralization of TNF-alpha to reduce the adverse effects associated with systemic neutralization of TNF-alpha.
Discovery of Akt Kinase Inhibitors through Structure-Based Virtual Screening and Their Evaluation as Potential Anticancer Agents
(2015-02-01)
Chuang, Chih-Hung
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Cheng, Ta-Chun
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Leu, Yu-Ling
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Chuang, Kuo-Hsiang
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Tzou, Shey-Cherng
Akt acts as a pivotal regulator in the PI3K/Akt signaling pathway and represents a potential drug target for cancer therapy. To search for new inhibitors of Akt kinase, we performed a structure-based virtual screening using the DOCK 4.0 program and the X-ray crystal structure of human Akt kinase. From the virtual screening, 48 compounds were selected and subjected to the Akt kinase inhibition assay. Twenty-six of the test compounds showed more potent inhibitory effects on Akt kinase than the reference compound, H-89. These 26 compounds were further evaluated for their cytotoxicity against HCT-116 human colon cancer cells and HEK-293 normal human embryonic kidney cells. Twelve compounds were found to display more potent or comparable cytotoxic activity compared to compound H-89 against HCT-116 colon cancer cells. The best results were obtained with Compounds a46 and a48 having IC50 values (for HCT-116) of 11.1 and 9.5 mu M, respectively, and selectivity indices (IC50 for HEK-293/IC50 for HCT-116) of 12.5 and 16.1, respectively. Through structure-based virtual screening and biological evaluations, we have successfully identified several new Akt inhibitors that displayed cytotoxic activity against HCT-116 human colon cancer cells. Especially, Compounds a46 and a48 may serve as useful lead compounds for further development of new anticancer agents.
Dual functional AuNRs@MnMEIOs nanoclusters for magnetic resonance imaging and photothermal therapy
(2014-05-01)
Chuang, Yao-Chen
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Lin, Chia-Jung
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Lo, Shih-Feng
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Wang, Jei-Lin
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Tzou, Shey-Cherng
A novel dual functional theranosis platform is developed based on manganese magnetism-engineered iron oxide (MnMEIO) and gold nanorods (AuNRs) to combine magnetic resonance (MR) imaging and photothermal therapy in one nanocluster. The platform showed improved T-2-weighted MR imaging and exhibited a near-infrared (NIR) induced temperature elevation due to the unique characteristics of AuNRs@MnMEIOs nanoclusters. The obtained dual functional spherical-shaped nanoclusters showed low cytotoxicity, and high cellular uptake efficiency. The AuNRs@MnMEIOs nanoclusters also demonstrated a 1.9 and 2.2 folds r(2) relaxivity value higher than those of monodispersed MnMEIO and Resovist. In addition, in vivo MR imaging study found that the contrast enhancements were -70.4 +/- 4.3% versus 7.5 +/- 3.0% in Her-2/neu overexpression tumors as compared to the control tumors. More importantly, NIR laser irradiation to the tumor site resulted in outstanding photothermal therapeutic efficacy and without damage to the surrounding tissue. In additional, the prepared dual functional AuNRs@MnMEIOs display high stability and furthermore disperse even in the presence of external magnet, showing that AuNRs@MnMEIOs nanoclusters can be manipulated by an external magnetic field. Therefore, such nanoclusters combined MR imaging and photothermal therapeutic functionality can be developed as a promising nanosystem for effective cancer diagnosis and therapy. (C) 2014 Elsevier Ltd. All rights reserved.
Functional Production of a Soluble and Secreted Single-Chain Antibody by a Bacterial Secretion System
(2014-05-13)
Cheng, Chiu-Min
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Tzou, Shey-Cherng
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Zhuang, Ya-Han
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Huang, Chien-Chiao
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Kao, Chien-Han
Single-chain variable fragments (scFvs) serve as an alternative to full-length monoclonal antibodies used in research and therapeutic and diagnostic applications. However, when recombinant scFvs are overexpressed in bacteria, they often form inclusion bodies and exhibit loss of function. To overcome this problem, we developed an scFv secretion system in which scFv was fused with osmotically inducible protein Y (osmY), a bacterial secretory carrier protein, for efficient protein secretion. Anti-EGFR scFv (alpha EGFR) was fused with osmY (N- and C-termini) and periplasmic leader sequence (pelB) to generate alpha EGFR-osmY, osmY-alpha EGFR, and pelB-alpha EGFR (control), respectively. In comparison with the control, both the osmY-fused alpha EGFR scFvs were soluble and secreted into the LB medium. Furthermore, the yield of soluble alpha EGFR-osmY was 20-fold higher, and the amount of secreted protein was 250-fold higher than that of osmY-alpha EGFR. In addition, the antigenbinding activity of both the osmY-fused alpha EGFRs was 2-fold higher than that of the refolded pelB-alpha EGFR from inclusion bodies. Similar results were observed with alpha TAG72-osmY and alpha Her2-osmY. These results suggest that the N-terminus of osmY fused with scFv produces a high yield of soluble, functional, and secreted scFv, and the osmY-based bacterial secretion system may be used for the large-scale industrial production of low-cost alpha EGFRprotein.
Imaging specificity of MR-optical imaging agents following the masking of surface charge by poly(ethylene glycol)
(2013-05-01)
Wu, Shou-Cheng
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Lin, Kun-Liang
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Wang, Tzu-Pin
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Tzou, Shey-Cherng
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Singh, Gyan
The coupling of specific antibodies to imaging agents often improves imaging specificity. However, free amine groups designed for the coupling can cause nonspecific binding of the imaging agents. We report here development of a nanocarrier, MnMEIO-silane-NH2-mPEG nanoparticles (NPs), consisting of a manganese-doped iron oxide nanoparticle core (MnMEIO), a copolymer shell of silane and amine-functionalized poly(ethylene glycol) (silane-EA-mPEG). The key feature in MnMEIO-silane-NH2-mPEG is the flexible PEG, which masks the non-conjugated reactive amine groups (-NH2 <-> -NH3+) and reduces nonspecific binding of MnMEIO-silane-NH2-mPEG to cells. The amine groups on MnMEIO-silane-NH2-mPEG were conjugated with the fluorescent dye, Cy777 or antibodies [Erbitux (Erb)] to form a MR-optical imaging contrast agent (MnMEIO-silane-NH2-(Erb)-mPEG) for EGFR-expressing tumors. Confocal microscopic and flow cytometric analyses showed that MnMEIO-silane-NH2-(Erb)-mPEG displayed low nonspecific binding. Moreover, TEM images showed that MnMEIO-silane-NH2-(Erb)-mPEG were endocytosed by EGFR-expressing cells. In line with their EGFR expression levels, A431, PC-3, and Colo-205 tumors treated with MnMEIO-silane-NH2-(Erb)-mPEG NPs showed -97.1%, -49.7%, and -2.8% contrast enhancement, respectively, in in vitro T-2-weighted MR imaging. In vivo T-2-weighted MR imaging and optical images showed that MnMEIO-silane-NH2-(Erb)mPEG could specifically and effectively target to EGFR-expressing tumors in nude mice; the relative contrast enhancements were 7.94 (at 2 h) and 7.59 (at 24 h) fold higher in A431 tumors as compared to the EGFR-negative Colo-205 tumors. On the contrary, MnMEIO-silane-NH2-(Erb) NPs showed only 1.44 (at 2 h) and 1.52 (at 24 h) fold higher in EGFR-positive tumors as compared to the EGFR-negative tumors. Finally, antibodies can be readily changed to allow imaging of other tumors bearing different antigens. These data indicate that masking surface charges on contrast agents is a useful strategy to improve imaging efficacy. (c) 2013 Elsevier Ltd. All rights reserved.
In Situ Activation of Pituitary-Infiltrating T Lymphocytes in Autoimmune Hypophysitis
(2017-03-06)
Lin, Han-Huei
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Gutenberg, Angelika
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Chen, Tzu-Yu
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Tsai, Nu-Man
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Lee, Chia-Jung
Autoimmune hypophysitis (AH) is a chronic inflammatory disease characterized by infiltration of T and B lymphocytes in the pituitary gland. The mechanisms through which infiltrating lymphocytes cause disease remain unknown. Using a mouse model of AH we assessed whether T lymphocytes undergo activation in the pituitary gland. Infiltrating T cells co-localized with dendritic cells in the pituitary and produced increased levels of interferon-gamma and interleukin-17 upon stimulation in vitro. Assessing proliferation of CD3- and B220-postive lymphocytes by double immunohistochemistry (PCNA-staining) and flow cytometry (BrdU incorporation) revealed that a discrete proportion of infiltrating T cells and B cells underwent proliferation within the pituitary parenchyma. This proliferation persisted into the late disease stage (day 56 post-immunization), indicating the presence of a continuous generation of autoreactive T and B cells within the pituitary gland. T cell proliferation in the pituitary was confirmed in patients affected by autoimmune hypophysitis. In conclusion, we show that pituitary-infiltrating lymphocytes proliferate in situ during AH, providing a previously unknown pathogenic mechanism and new avenues for treatment.
In vitro and in vivo imaging of peroxynitrite by a ratiometric boronatebased fluorescent probe
(2017-05-15)
Palanisamy, Sathyadevi
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Wu, Pei-Yu
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Wu, Shou-Cheng
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Chen, Yu-Jen
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Tzou, Shey-Cherng
Peroxynitrite (ONOO-) is an important species involved in many physiopathological processes. Progresses have been made in developing novel fluorescent probes to detect peroxynitrite with relatively high sensitivity and specificity. Herein, we report the synthesis, characterization and biological applications of a new boronate-based fluorescent probe, 4-MB. The studies showed that 4-MB exhibits a dual ratiometric and calorimetric response toward peroxynitrite due to ONOO--triggered oxidative reaction. A possible mechanism of the oxidation reaction was proposed and the reaction product was isolated and characterized using different spectroscopic methods. We have thoroughly demonstrated the utility of 4-MB for intracellular peroxynitrite imaging. Further, we showed that 4-MB can be potentially employed to visualize exogenous and endogenous peroxynitrite in RAW264.7 macrophages, EAhy926 cells, zebrafish and in live tissues from a high-fat diet-induced obese mouse model.
Lipo-PEG-PEI complex as an intracellular transporter for protein therapeutics
(2019-01-01)
Lin, Yu-Ling
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Chen, Chia-Hung
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Liu, Yen-Ku
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Huang, Tse-Hung
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Tsai, Nu-Man
Background: Protein or peptide drugs are emerging therapeutics for treating human diseases. However, current protein drugs are typically limited to acting on extracellular/cell membrane components associated with the diseases, while intracellular delivery of recombinant proteins replaces or replenishes faulty/missing proteins and remains inadequate. In this study, we developed a convenient and efficient intracellular protein delivery vehicle. Materials and methods: A cationic liposomal polyethylenimine and polyethylene glycol complex (LPPC) was developed to noncovalently capture proteins for protein transfer into cells via endocytosis. beta-glucuronidase (beta G) was used in vitro and in vivo as a model enzyme to demonstrate the enzymatic activity of the intracellular transport of a protein. Results: The endocytosed protein/LPPC complexes escaped from lysosomes, and the bound protein dissociated from LPPC in the cytosol. The enzymatic activity of beta G was well preserved after intracellular delivery in vitro and in vivo. Conclusion: Using LPPC as an intracellular protein transporter for protein therapeutics, we illustrated that LPPC may be an effective and convenient tool for studying diseases and developing therapeutics.
Measurement of Poly(ethylene glycol) by Cell-Based Anti-poly(ethylene glycol) ELISA
(2010-03-15)
Chuang, Kuo-Hsiang
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Tzou, Shey-Cherng
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Cheng, Ta-Chun
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Kao, Chien-Han
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Tseng, Wei-Lung
Poly(ethylene glycol) (PEG) is increasingly used in clinical and experimental medicine. However, quantification of PEG and PEGylated small molecules remains laborious and unsatisfactory. In this report, we stably expressed a functional anti-PEG antibody on the surface of BALB 3T3 cells (3T3/alpha PEG cells) to develop a competitive enzyme-linked immunosorbent assay (ELISA) for PEG quantification. The alpha-PEG cell-coated plate bound biotinylated PEG(5K) (CH(3)-PEG(5K)-biotin) and CH(3)-PEG(5K)-(131)I more effectively than did a traditional anti-PEG antibody-coated plate. Competitive binding between PEG (2, 5, 10, or 20 kDa) and a known amount of CH(3)-PEG(5K)-biotin allowed construction of a reproducible competition curve. The alpha PEG cell-based competition ELISA measured small molecules derivatized by PEG(2K), PEG(5K), PEG(10K), PEG(20K), and PEG(5K) at concentrations as low as 58.6, 14.6, 3.7, 3.7, and 14.6 ng/mL respectively. Notably, the presence of serum or bovine serum albumin enhanced PEG measurement by the alpha PEG cell-based competition ELISA. Finally, we show here that the alpha PEG cell-based competition ELISA accurately delineated the pharmacokinetics of PEG(5K), comparable to those determined by direct measurement of radioactivity in blood after intravenous injection of CH(3)-PEG(5K)-(131)I into mice. This quantitative strategy may provide a simple and sensitive method for quantifying PEG and PEGylated small molecules in vivo.
Near-infrared templated fluorescent probe for nitroxyl: Selective and sensitive turn-on detection in living cells
(2020-05-01)
Palanisamy, Sathyadevi
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Chen, Li-Fong
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Tzou, Shey-Cherng
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Wang, Yun-Ming
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交大名義發表
Bioactive species, including reactive oxygen species, reactive nitrogen species, and reactive sulfur species, play important roles in physiological processes; thus, it is very valuable to monitor such species in subcellular systems. Herein, for the first time, we report a turn-on highly red-emissive near-infrared (NIR) fluorescent probe, LF3 (3), for nitroxyl (HNO) which is composed of a triphenylphosphine moiety and possesses long-wavelength emission (740 - 840 nm), to the best of our knowledge. The probe, LF3, is highly selective and sensitive for HNO with a response time of 6 min and a detection limit as low as 15 nM. The quantum yield values LF3 and HNO added LF3 obtained from the fluorescence studies are 0.005 and 0.264, respectively. More importantly, LF3 is able to image both exogenous and endogenous nitroxyl in living cells without any interference from the background fluorescence.
Peptide-based MRI contrast agent and near-infrared fluorescent probe for intratumoral legumain detection
(2014-01-01)
Chen, Yu-Jen
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Wu, Shou-Cheng
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Chen, Chung-Yung
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Tzou, Shey-Cherng
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Cheng, Tian-Lu
Recent studies suggest that intratumoral legumain promotes tumorigenesis. To monitor legumain activity in tumors, we developed a new MM contrast agent ([Gd-NBCB-TTDA-Leg(L)]) and a NIR fluorescence probe (CyTE777-Leg(L)-CyTE807). The MRI contrast agent was prepared by introduction of cyclobutyl and benzyl group residues to TTDA (3,6,10-tri(carboxymethyl)-3,6,10-triaza-dodecanedioic acid), followed by the attachment of a legumain-specific substrate peptide (Leg(L)). The NIR fluorescence probe was designed by conjugating two NIR fluorochromes (CyTE777 and CyTE807) with Leg(L). Peptide cleavage of the MM contrast agent by legumain can increase its hydrophobicity and promote rotational correlation time (tau(R)). Peptide cleavage of the NIR probes by the legumain relieves the self quench of the probe. Peptide cleavage of the MRI contrast agent and the NIR fluorescence probe by legumain were confirmed by T-1 relaxometric studies and by fluorescence studies, respectively. In vivo MR images showed that [Gd-NBCB-TTDA-Leg(L)] attained 55.3 fold (254.2% versus 4.6%, at 2.0 h post-injection) higher imaging enhancement, as compared with control contrast agent bearing a noncleaveable peptide ([Gd-NBCB-TTDA-Leg(D)], in the CT-26 (legumain(+)) tumors. Similarly, optical imaging probe CyTE777-Leg(L)-CyTE807 attained 15.2 fold (3.34 x 10(9) photons/min versus 0.22 x 10(9) photons/min, at 24.0 h post-injection) higher imaging enhancement in the CT-26 (legumain(+)) tumors, compared to a NIR control probe (CyTE777-Leg(D)-CyTE807). These data indicate that the [Gd-NBCB-TTDA-Leg(L)] and the CyTE777-Leg(L)-CyTE807 probes may be promising tools to image the legumain-expressing cancers for diagnoses and targeted treatments. (C) 2013 Elsevier Ltd. All rights reserved.
Selective antibody activation through protease-activated pro-antibodies that mask binding sites with inhibitory domains
(2017-09-14)
Chen, I-Ju
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Chuang, Chih-Hung
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Hsieh, Yuan-Chin
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Lu, Yun-Chi
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Lin, Wen-Wei
Systemic injection of therapeutic antibodies may cause serious adverse effects due to on-target toxicity to the antigens expressed in normal tissues. To improve the targeting selectivity to the region of disease sites, we developed protease-activated pro-antibodies by masking the binding sites of antibodies with inhibitory domains that can be removed by proteases that are highly expressed at the disease sites. The latency-associated peptide (LAP), C2b or CBa of complement factor 2/B were linked, through a substrate peptide of matrix metalloproteinase-2 (MMP-2), to an anti-epidermal growth factor receptor (EGFR) antibody and an anti-tumor necrosis factor-alpha (TNF-alpha) antibody. Results showed that all the inhibitory domains could be removed by MMP-2 to restore the binding activities of the antibodies. LAP substantially reduced (53.8%) the binding activity of the anti-EGFR antibody on EGFR-expressing cells, whereas C2b and CBa were ineffective (21% and 9.3% reduction, respectively). Similarly, LAP also blocked 53.9% of the binding activity of the anti-TNF-alpha antibody. Finally, molecular dynamic simulation showed that the masking efficiency of LAP, C2b and CBa was 33.7%, 10.3% and -5.4%, respectively, over the binding sites of the antibodies. This strategy may aid in designing new protease-activated pro-antibodies that attain high therapeutic potency yet reduced systemic on-target toxicity.
Sensitivity of PEGylated Interferon Detection by Anti-Polyethylene Glycol (PEG) Antibodies Depends on PEG Length
(2013-08-01)
Cheng, Ta-Chun
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Chuang, Kuo-Hsiang
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Chen, Michael
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Wang, Hsin-Ell
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Tzou, Shey-Cherng
Attachment of poly(ethylene glycol) to proteins can mask immune epitopes to increase serum half-life, reduce immunogenicity, and enhance in vivo biological efficacy. However, PEGylation mediated epitope-masking may also limit sensitivity and accuracy of traditional ELISA. We previously described an anti-PEG-based sandwich ELISA for universal assay of PEGylated molecules. Here, we compared the quantitative assessment of PEGylated interferons by anti-PEG and traditional anti-interferon sandwich ELISA. The detection limits for PEG-Intron (12k-PEG) and Pegasys (40k-PEG) were 1.9 and 0.03 ng/mL for anti-PEG ELISA compared to 0.18 and 0.42 ng/mL for traditional anti-interferon sandwich ELISA. These results indicate that the anti-PEG sandwich ELISA was insensitive to PEGylation mediated epitope-masking and the sensitivity increased in proportion to the length of PEG. By contrast, PEG-masking interfered with detection by traditional anti-interferon sandwich ELISA. Human and mouse serum did not affect the sensitivity of anti-PEG ELISA but impeded traditional anti-interferon sandwich ELISA. The anti-PEG sandwich ELISA was comparable to anti-interferon sandwich ELISA and radioassay of I-131-Pegasys in pharmacokinetic studies in mice. The anti-PEG sandwich ELISA provides a sensitive, accurate, and convenient quantitative measurement of PEGylated protein drugs.
The inhibitory effect of 7, 7 ''-dimethoxyagastisflavone on the metastasis of melanoma cells via the suppression of F-actin polymerization
(2017-09-01)
Lin, Ching-Min
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Lin, Yu-Ling
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Ho, Shu-Yi
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Chen, Pin-Rong
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Tsai, Yi-Hsuan
7,7"-Dimethoxyagastisflavone (DMGF), a biflavonoid isolated from Taxus x media cv. Hicksii, induces apoptotic and autophagic cell death. However, whether DMGF suppresses tumor metastasis is unclear. The aim of this study was to investigate the anti-metastatic activities of DMGF on the metastatic processes of melanoma cells in vivo and in vitro. A transwell assay showed that DMGF could effectively attenuate the motility of B16F10 cells, and the results of real-time PCR revealed that DMGF also suppressed the expressions of matrix metalloproteinase-2 (MMP-2). Moreover, DMGF did not influence tube formation but inhibited the migration of endothelial cells. Furthermore, animal models were used to monitor the effects of DMGF on tumor metastasis, and all models showed that DMGF significantly suppressed the metastatic behaviors of B16F10 cells, including intravasation, colonization, and invasion of the lymphatic duct. In addition, DMGF could also reduce the densities of the blood vessels in the tumor area in vivo. Further investigation of the molecular mechanisms of anti-metastatic activity revealed that DMGF can down-regulate the levels of key modulators of the Cdc42/Rac1 pathway to interfere in F-actin polymerization and suppress the formation of lamellipodia by reducing the phosphorylation of CREB. These data suggested that DMGF presents anti-metastatic activities in B16F10 melanoma cells. Here, we demonstrated that DMGF can inhibit the metastasis of highly invasive melanoma cancer cells through the down-regulation of F-actin polymerization. Considering these findings, DMGF may be further developed to serve as a chemoprevention drug for patients with metastatic melanoma.