The Experts below are selected from a list of 22668 Experts worldwide ranked by ideXlab platform
Donald S Coffey - One of the best experts on this subject based on the ideXlab platform.
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identification and characterization of nuclease stabilized rna molecules that bind human prostate cancer cells via the prostate specific membrane antigen
Cancer Research, 2002Co-Authors: Shawn E Lupold, Brian Hicke, Donald S CoffeyAbstract:We have identified two synthetic oligonucleotides (Aptamers) that bind to prostate cancer cells,with low nanomolar affinity, via the extracellular portion of the prostate-specificmembrane antigen (PSMA). These two specific Aptamers were selected from an initial 40mer library of ∼6 × 10 14 random-sequence RNA molecules for their ability to bind to a recombinant protein representing the extracellular 706 amino acids of PSMA, termed xPSM. Six rounds of in vitro selection were performed, enriching for xPSM binding as monitored by Aptamer inhibition of xPSM N -acetyl-α-linked acid dipeptidase (NAALADase) enzymatic activity. By round six, 95% of the Aptamer pool consisted of just two sequences. These two Aptamers, termed xPSM-A9 and xPSM-A10, were cloned and found to be unique, sharing no consensus sequences. The affinity of each Aptamer for PSMA was quantitated by its ability to inhibit NAALADase activity. Aptamer xPSM-A9 inhibits PSMA noncompetitively with an average K i of 2.1 nm, whereas Aptamer xPSM-A10 inhibits competitively with an average K i of 11.9 nm. Distinct modes of inhibition suggest that each Aptamer identifies a unique extracellular epitope of xPSM. One Aptamer was truncated from 23.4 kDa to 18.5 kDa and specifically binds LNCaP human prostate cancer cells expressing PSMA but not PSMA-devoid PC-3 human prostate cancer cells. These are the first reported RNA Aptamers selected to bind a tumor-associated membrane antigen and the first application of RNA Aptamers to a prostate specific cell marker. These Aptamers may be used clinically as NAALADase inhibitors or be modified to carry imaging agents and therapeutic agents directed to prostate cancer cells.
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identification and characterization of nuclease stabilized rna molecules that bind human prostate cancer cells via the prostate specific membrane antigen
Cancer Research, 2002Co-Authors: Shawn E Lupold, Brian Hicke, Yun Lin, Donald S CoffeyAbstract:We have identified two synthetic oligonucleotides (Aptamers) that bind to prostate cancer cells,with low nanomolar affinity, via the extracellular portion of the prostate-specificmembrane antigen (PSMA). These two specific Aptamers were selected from an initial 40mer library of approximately 6 x 10(14) random-sequence RNA molecules for their ability to bind to a recombinant protein representing the extracellular 706 amino acids of PSMA, termed xPSM. Six rounds of in vitro selection were performed, enriching for xPSM binding as monitored by Aptamer inhibition of xPSM N-acetyl-alpha-linked acid dipeptidase (NAALADase) enzymatic activity. By round six, 95% of the Aptamer pool consisted of just two sequences. These two Aptamers, termed xPSM-A9 and xPSM-A10, were cloned and found to be unique, sharing no consensus sequences. The affinity of each Aptamer for PSMA was quantitated by its ability to inhibit NAALADase activity. Aptamer xPSM-A9 inhibits PSMA noncompetitively with an average K(i) of 2.1 nM, whereas Aptamer xPSM-A10 inhibits competitively with an average K(i) of 11.9 nM. Distinct modes of inhibition suggest that each Aptamer identifies a unique extracellular epitope of xPSM. One Aptamer was truncated from 23.4 kDa to 18.5 kDa and specifically binds LNCaP human prostate cancer cells expressing PSMA but not PSMA-devoid PC-3 human prostate cancer cells. These are the first reported RNA Aptamers selected to bind a tumor-associated membrane antigen and the first application of RNA Aptamers to a prostate specific cell marker. These Aptamers may be used clinically as NAALADase inhibitors or be modified to carry imaging agents and therapeutic agents directed to prostate cancer cells.
Shawn E Lupold - One of the best experts on this subject based on the ideXlab platform.
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identification and characterization of nuclease stabilized rna molecules that bind human prostate cancer cells via the prostate specific membrane antigen
Cancer Research, 2002Co-Authors: Shawn E Lupold, Brian Hicke, Donald S CoffeyAbstract:We have identified two synthetic oligonucleotides (Aptamers) that bind to prostate cancer cells,with low nanomolar affinity, via the extracellular portion of the prostate-specificmembrane antigen (PSMA). These two specific Aptamers were selected from an initial 40mer library of ∼6 × 10 14 random-sequence RNA molecules for their ability to bind to a recombinant protein representing the extracellular 706 amino acids of PSMA, termed xPSM. Six rounds of in vitro selection were performed, enriching for xPSM binding as monitored by Aptamer inhibition of xPSM N -acetyl-α-linked acid dipeptidase (NAALADase) enzymatic activity. By round six, 95% of the Aptamer pool consisted of just two sequences. These two Aptamers, termed xPSM-A9 and xPSM-A10, were cloned and found to be unique, sharing no consensus sequences. The affinity of each Aptamer for PSMA was quantitated by its ability to inhibit NAALADase activity. Aptamer xPSM-A9 inhibits PSMA noncompetitively with an average K i of 2.1 nm, whereas Aptamer xPSM-A10 inhibits competitively with an average K i of 11.9 nm. Distinct modes of inhibition suggest that each Aptamer identifies a unique extracellular epitope of xPSM. One Aptamer was truncated from 23.4 kDa to 18.5 kDa and specifically binds LNCaP human prostate cancer cells expressing PSMA but not PSMA-devoid PC-3 human prostate cancer cells. These are the first reported RNA Aptamers selected to bind a tumor-associated membrane antigen and the first application of RNA Aptamers to a prostate specific cell marker. These Aptamers may be used clinically as NAALADase inhibitors or be modified to carry imaging agents and therapeutic agents directed to prostate cancer cells.
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identification and characterization of nuclease stabilized rna molecules that bind human prostate cancer cells via the prostate specific membrane antigen
Cancer Research, 2002Co-Authors: Shawn E Lupold, Brian Hicke, Yun Lin, Donald S CoffeyAbstract:We have identified two synthetic oligonucleotides (Aptamers) that bind to prostate cancer cells,with low nanomolar affinity, via the extracellular portion of the prostate-specificmembrane antigen (PSMA). These two specific Aptamers were selected from an initial 40mer library of approximately 6 x 10(14) random-sequence RNA molecules for their ability to bind to a recombinant protein representing the extracellular 706 amino acids of PSMA, termed xPSM. Six rounds of in vitro selection were performed, enriching for xPSM binding as monitored by Aptamer inhibition of xPSM N-acetyl-alpha-linked acid dipeptidase (NAALADase) enzymatic activity. By round six, 95% of the Aptamer pool consisted of just two sequences. These two Aptamers, termed xPSM-A9 and xPSM-A10, were cloned and found to be unique, sharing no consensus sequences. The affinity of each Aptamer for PSMA was quantitated by its ability to inhibit NAALADase activity. Aptamer xPSM-A9 inhibits PSMA noncompetitively with an average K(i) of 2.1 nM, whereas Aptamer xPSM-A10 inhibits competitively with an average K(i) of 11.9 nM. Distinct modes of inhibition suggest that each Aptamer identifies a unique extracellular epitope of xPSM. One Aptamer was truncated from 23.4 kDa to 18.5 kDa and specifically binds LNCaP human prostate cancer cells expressing PSMA but not PSMA-devoid PC-3 human prostate cancer cells. These are the first reported RNA Aptamers selected to bind a tumor-associated membrane antigen and the first application of RNA Aptamers to a prostate specific cell marker. These Aptamers may be used clinically as NAALADase inhibitors or be modified to carry imaging agents and therapeutic agents directed to prostate cancer cells.
Weihong Tan - One of the best experts on this subject based on the ideXlab platform.
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engineering Aptamer with enhanced affinity by triple helix based terminal fixation
Journal of the American Chemical Society, 2019Co-Authors: Lianhui Zhao, Xiaochen Yan, Yunfei Huang, Xingguo Liang, Liqin Zhang, Sai Wang, Weihong TanAbstract:The affinity of Aptamers relies on their adaptive folding, but the excessive flexibility of the Aptamer backbone usually hampers the folding process. Thus, there is an urgent need to engineer Aptamers with more stable and defined structures. Herein, we report a postselection strategy for stabilizing Aptamer structures, by fixing both termini of the Aptamer with a length-optimized triple helix structure. An anti-lysozyme Aptamer was engineered in this way, and its affinity was enhanced by almost 10-fold. An electrochemical aptasensor was designed based on this engineered Aptamer, assisted by a DNA tetrahedron as a spacer to orient the Aptamer. The aptasensor achieved a 180-fold lower limit of detection than that achieved by the aptasensor without termini-fixed Aptamer and exhibited high sensitivity and selectivity toward lysozyme in real red wine samples. This work sheds light on engineering Aptamers to achieve enhanced affinity and on the application of aptasensors in complex matrices.
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cancer cell targeting using multiple Aptamers conjugated on nanorods
Analytical Chemistry, 2008Co-Authors: Yufen Huang, Huantsung Chang, Weihong TanAbstract:Molecular recognition toward specific cells is a key issue for effective disease, such as cancer, diagnosis and therapy. Although many molecular probes such as Aptamers and antibodies can recognize the unique molecular signatures of cancer cells, some of these probes only have relatively weak binding affinities. This results in poor signaling and hinders cell targeting. Here, we use Au-Ag nanorods (NRs) as a nanoplatform for multivalent binding by multiple Aptamers on the rod to increase both the signal and binding strengths of these Aptamers in cancer cell recognition. Up to 80 fluorophore-labeled Aptamers can be attached on a 12 nm x 56 nm NR, resulting in a much stronger fluorescence signal than that of an individual dye-labeled Aptamer probe. The molecular assembly of Aptamers on the NR surfaces also significantly improves the binding affinity with cancer cells through simultaneous multivalent interactions with the cell membrane receptors. This leads to an affinity at least 26-fold higher than the intrinsic affinity of the original Aptamer probes. As determined by flow cytometric measurements, an enhancement in fluorescence signal in excess of 300-fold is obtained for the NR-Aptamer-labeled cells compared with those labeled by individual Aptamer probes. Therefore, the molecular assembly of Aptamers clearly shows potential applications for the elucidation of cells with low density of binding sites, or with relatively weak binding probes, and can thus greatly improve our ability to perform cellular imaging and targeting. This is an excellent example of using nanomaterials to develop advanced molecular binders with greatly improved properties for cellular studies.
Brian Hicke - One of the best experts on this subject based on the ideXlab platform.
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identification and characterization of nuclease stabilized rna molecules that bind human prostate cancer cells via the prostate specific membrane antigen
Cancer Research, 2002Co-Authors: Shawn E Lupold, Brian Hicke, Donald S CoffeyAbstract:We have identified two synthetic oligonucleotides (Aptamers) that bind to prostate cancer cells,with low nanomolar affinity, via the extracellular portion of the prostate-specificmembrane antigen (PSMA). These two specific Aptamers were selected from an initial 40mer library of ∼6 × 10 14 random-sequence RNA molecules for their ability to bind to a recombinant protein representing the extracellular 706 amino acids of PSMA, termed xPSM. Six rounds of in vitro selection were performed, enriching for xPSM binding as monitored by Aptamer inhibition of xPSM N -acetyl-α-linked acid dipeptidase (NAALADase) enzymatic activity. By round six, 95% of the Aptamer pool consisted of just two sequences. These two Aptamers, termed xPSM-A9 and xPSM-A10, were cloned and found to be unique, sharing no consensus sequences. The affinity of each Aptamer for PSMA was quantitated by its ability to inhibit NAALADase activity. Aptamer xPSM-A9 inhibits PSMA noncompetitively with an average K i of 2.1 nm, whereas Aptamer xPSM-A10 inhibits competitively with an average K i of 11.9 nm. Distinct modes of inhibition suggest that each Aptamer identifies a unique extracellular epitope of xPSM. One Aptamer was truncated from 23.4 kDa to 18.5 kDa and specifically binds LNCaP human prostate cancer cells expressing PSMA but not PSMA-devoid PC-3 human prostate cancer cells. These are the first reported RNA Aptamers selected to bind a tumor-associated membrane antigen and the first application of RNA Aptamers to a prostate specific cell marker. These Aptamers may be used clinically as NAALADase inhibitors or be modified to carry imaging agents and therapeutic agents directed to prostate cancer cells.
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identification and characterization of nuclease stabilized rna molecules that bind human prostate cancer cells via the prostate specific membrane antigen
Cancer Research, 2002Co-Authors: Shawn E Lupold, Brian Hicke, Yun Lin, Donald S CoffeyAbstract:We have identified two synthetic oligonucleotides (Aptamers) that bind to prostate cancer cells,with low nanomolar affinity, via the extracellular portion of the prostate-specificmembrane antigen (PSMA). These two specific Aptamers were selected from an initial 40mer library of approximately 6 x 10(14) random-sequence RNA molecules for their ability to bind to a recombinant protein representing the extracellular 706 amino acids of PSMA, termed xPSM. Six rounds of in vitro selection were performed, enriching for xPSM binding as monitored by Aptamer inhibition of xPSM N-acetyl-alpha-linked acid dipeptidase (NAALADase) enzymatic activity. By round six, 95% of the Aptamer pool consisted of just two sequences. These two Aptamers, termed xPSM-A9 and xPSM-A10, were cloned and found to be unique, sharing no consensus sequences. The affinity of each Aptamer for PSMA was quantitated by its ability to inhibit NAALADase activity. Aptamer xPSM-A9 inhibits PSMA noncompetitively with an average K(i) of 2.1 nM, whereas Aptamer xPSM-A10 inhibits competitively with an average K(i) of 11.9 nM. Distinct modes of inhibition suggest that each Aptamer identifies a unique extracellular epitope of xPSM. One Aptamer was truncated from 23.4 kDa to 18.5 kDa and specifically binds LNCaP human prostate cancer cells expressing PSMA but not PSMA-devoid PC-3 human prostate cancer cells. These are the first reported RNA Aptamers selected to bind a tumor-associated membrane antigen and the first application of RNA Aptamers to a prostate specific cell marker. These Aptamers may be used clinically as NAALADase inhibitors or be modified to carry imaging agents and therapeutic agents directed to prostate cancer cells.
Haizhen Zhu - One of the best experts on this subject based on the ideXlab platform.
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inhibition of hepatitis c virus infection by dna Aptamer against ns2 protein
PLOS ONE, 2014Co-Authors: Yimin Gao, Darong Yang, Xiaohong Fang, Binbin Xue, Fei Zhou, Xiaohong Wang, Nianli Liu, Haizhen ZhuAbstract:NS2 protein is essential for hepatitis C virus (HCV) replication. NS2 protein was expressed and purified. Aptamers against NS2 protein were raised and antiviral effects of the Aptamers were examined. The molecular mechanism through which the Aptamers exert their anti-HCV activity was investigated. The data showed that Aptamer NS2-3 inhibited HCV RNA replication in replicon cell line and infectious HCV cell culture system. NS2-3 and another Aptamer NS2-2 were demonstrated to inhibit infectious virus production without cytotoxicity in vitro. They did not affect hepatitis B virus replication. Interferon beta (IFN-β) and interferon-stimulated genes (ISGs) were not induced by the Aptamers in HCV-infected hepatocytes. Furthermore, our study showed that N-terminal region of NS2 protein is involved in the inhibition of HCV infection by NS2-2. I861T within NS2 is the major resistance mutation identified. Aptamer NS2-2 disrupts the interaction of NS2 with NS5A protein. The data suggest that NS2-2 Aptamer against NS2 protein exerts its antiviral effects through binding to the N-terminal of NS2 and disrupting the interaction of NS2 with NS5A protein. NS2-specific Aptamer is the first NS2 inhibitor and can be used to understand the mechanisms of virus replication and assembly. It may be served as attractive candidates for inclusion in the future HCV direct-acting antiviral combination therapies.
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inhibition of hepatitis c virus infection by dna Aptamer against envelope protein
Antimicrobial Agents and Chemotherapy, 2013Co-Authors: Darong Yang, Xianghe Meng, Ying Long, Bin Liu, Xiaohong Fang, Haizhen ZhuAbstract:Hepatitis C virus (HCV) envelope protein (E1E2) is essential for virus binding to host cells. Aptamers have been demonstrated to have strong promising applications in drug development. In the current study, a cDNA fragment encoding the entire E1E2 gene of HCV was cloned. E1E2 protein was expressed and purified. Aptamers for E1E2 were selected by the method of selective evolution of ligands by exponential enrichment (SELEX), and the antiviral actions of the Aptamers were examined. The mechanism of their antiviral activity was investigated. The data show that selected Aptamers for E1E2 specifically recognize the recombinant E1E2 protein and E1E2 protein from HCV-infected cells. CD81 protein blocks the binding of Aptamer E1E2-6 to E1E2 protein. Aptamers against E1E2 inhibit HCV infection in an infectious cell culture system although they have no effect on HCV replication in a replicon cell line. Beta interferon (IFN-β) and IFN-stimulated genes (ISGs) are not induced in virus-infected hepatocytes with Aptamer treatment, suggesting that E1E2-specific Aptamers do not induce innate immunity. E2 protein is essential for the inhibition of HCV infection by Aptamer E1E2-6, and the Aptamer binding sites are located in E2. Q412R within E1E2 is the major resistance substitution identified. The data indicate that an Aptamer against E1E2 exerts its antiviral effects through inhibition of virus binding to host cells. Aptamers against E1E2 can be used with envelope protein to understand the mechanisms of HCV entry and fusion. The Aptamers may hold promise for development as therapeutic drugs for hepatitis C patients.
