Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.3.1.108 (TAT)
 2,389 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Human monoclonal antibodies are promising agents for the development of more selective anticancer therapeutics. However, the tumor-targeting efficiency of most anticancer antibodies is severely limited by their poor penetration into the tumor mass. Recent studies have shown that a peptide derived from the HIV TAT protein could improve the distribution of cytoplasmic reporter proteins when administered systemically as fusion proteins or cross-linked chimeras. In this article, we tested by quantitative biodistribtution analysis whether conjugation to TAT peptides could improve the tumor targeting properties of scFv(L19)-Cys: an engineered human antibody fragment specific for the ED-B domain of fibronectin, a marker located in the modified extracellular matrix surrounding tumor neovasculature. Our results show that TAT peptides, consisting either of L-amino acids or D-amino acids, can efficiently transduce target cells when conjugated to fluorophores and/or antibody fragments, suggesting a receptor-independent cell entry mechanism. However, conjugation of scFv(L19)-Cys to TAT peptides resulted in a severely reduced tumor targeting performance compared to the unconjugated antibody, as measured in murine F9 teratocarcinoma-bearing mice, after intravenous injection of the radiolabeled antibody preparations. Our results outline the usefulness of TAT peptides for the efficient in vitro transduction of cells with globular proteins. In particular, the use of TAT peptides composed of D-amino acids may significantly reduce proteolytic degradation. At the same time, the poor biodistribution properties of antibody-TAT conjugates cast doubts over the applicability of this methodology for the delivery of biopharmaceuticals in vivo.
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PMID:Quantitation of the tumor-targeting properties of antibody fragments conjugated to cell-permeating HIV-1 TAT peptides. 1212 Nov 27

Apoptosis or programmed cell death plays an important role in a wide variety of physiologic processes and is regulated by proteins of the Bcl-2 family consisting of both antiapoptotic and proapoptotic factors. The direct involvement of the Bcl-2 protein family in the process of mast cell apoptosis has not been clarified. In the present work we have used a single-chain antibody (scFv) raised against Bcl-2 derived from a semisynthetic human phage-display antibody library. The addition of TAT sequence, which is responsible for translocation through the membrane, endows the anti-Bcl-2-scFv with the ability to penetrate living cells. Moreover, it specifically neutralizes Bcl-2 intracellularly by binding to the BH1 domain and eradicates its antiapoptotic activity in 2 types of mast cells and in a human breast cancer cell line.
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PMID:A novel strategy using single-chain antibody to show the importance of Bcl-2 in mast cell survival. 1279 61

We try to develop a method for delivering antibody from blood circulation through blood brain barrier to brain. In order to achieve this goal, antibody has to cross cellular membrane of brain capillary endothelial cells twice. As a first step of our study, we examined the ability for scFv antibody to cross cellular membrane of RBL-2H3 cells once and be delivered into the inside of the cultured cells with the help of TAT peptide. TAT peptide was originally found in Tat protein from the HIV-1 virus and known as one of protein transduction domains. First, oligonucleotide encoding TAT peptide was linked to 5' terminal of gene fragment of scFv antibody by PCR technology. TAT-linked scFv gene fragment was subcloned into pET-23b vector and successfully expressed in E. coli as inclusion body. After solubilization and purification, TAT-linked scFv recombinant protein was added to the culture of RBL-2H3 cells. TAT-linked scFv delivered into RBL-2H3 cells was detected by means of immunocytochemistry using fluorescence microscopy. TAT-linked scFv crossed cellular membrane more efficiently than scFv without TAT peptide.
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PMID:[Study on a method for delivering scFv recombinant antibody into cultured cells]. 1474 Apr 3

Apoptosis or programmed cell death plays an important role in a wide variety of physiological processes. Apoptosis is regulated by proteins of the Bcl-2 family consisting of both anti-apoptotic and pro-apoptotic factors. The direct involvement of the Bcl-2 protein family in the process of mast cell apoptosis has not been clarified. We have used a single-chain antibody (scFv) raised against Bcl-2 derived from human phage-display antibody library. The addition of TAT sequence, which is responsible for translocation through the membrane, endows the anti-Bcl-2-scFv with the ability to penetrate living cells. The association of anti-Bcl-2-scFv-TAT with intracellular Bcl-2 leads to neutralization of Bcl-2 and eradication of its anti-apoptotic activity in two types of mast cells and in a human breast cancer cell line. Moreover, we found by mass spectrometry and co-immunoprecipitation assay that heat shock protein 90b (Hsp90b) forms a complex with Bcl-2 in mast cells. Thus, understanding the network of interactions between Bcl-2 and non-Bcl-2 family members might help in development of more specific drugs and cancer therapy.
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PMID:The involvement of Bcl-2 in mast cell apoptosis. 1660 36