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)

Radioresistance and limitation of irradiative dosage usually lead to failure in depletion of hypoxic tumors. Herein we developed multifunctional mesoporous silica nanoparticles (MSNs) as a carrier of a novel anticancer selenoamino acid (selenocystine, SeC), to achieve synergistic chemo-/radiotherapy. This multifunctional nanosystem effectively sensitizes cancer cells to X-ray radiotherapy. Conjugation of TAT cell penetrating peptide and transferrin to the surface of MSNs significantly enhances its internalization in cancer cells through receptor-mediated endocytosis. SeC@MSNs-Tf/TAT significantly enhanced X-ray-induced growth inhibition in cervical cancer cells by induction of apoptosis, mainly through death receptor-mediated extrinsic apoptotic pathway. Upon radiation, SeC@MSNs-Tf/TAT promoted intracellular ROS overproduction, which induced apoptotic cell death by affecting p53, AKT and MAPKs pathways. Furthermore, SeC@MSNs-Tf/TAT also significantly inhibited HeLa tumor growth in nude mice model through suppression of cell proliferation and induction of apoptosis. In vivo toxicity of the SeC@MSNs-Tf/TAT nanoparticles was investigated using the mouse model. The results of histological analysis revealed that, the nanoparticles did not show any obvious damage to these major organs under the experimental conditions, including heart, liver, spleen, lung and kidney. Taken together, this study demonstrates an effective and safe strategy for cancer-targeted chemo-/radiotherapy of human cancers.
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PMID:Dual-function nanosystem for synergetic cancer chemo-/radiotherapy through ROS-mediated signaling pathways. 2577 Sep 95

Cell-penetrating peptides (CPPs) are increasingly important in transporting macromolecules across cell membranes, but their use remains confined to narrow clinical applications due to the systemic toxicity induced by their positive charges. Several newly discovered electronic neutral penetrating peptides are not attracting much attention because their penetrating capacity is normally far less powerful than cationic or amphiphilic CPPs. In this study, we found the electronic neutral cyclic peptide cyclosporin A (CsA) exhibited 5.6-fold and 19.1-fold stronger penetrating capacity, respectively, than two reported electronic neutral peptides PFVYLI (PFV) and pentapeptide VPTLQ (VPT) in MCF-7 human breast cancer cells. To systematically evaluate the efficiency and toxicity of CsA, we utilized CsA to deliver a membrane-impenetrable pro-apoptotic peptide (PAD) and compared this to the well-established cationic penetrating peptide TAT (RKKRRQRRR). By conjugating CsA to PAD, the internalization of PAD increased 2.2- to 4.7-fold in four different tumor cell lines, and that of CsA-PAD conjugate was significantly higher than TAT-PAD conjugate in MCF-7 and HeLa human cervical cancer cells. Cytotoxicity studies demonstrated that CsA-PAD exhibited a large increase in cell cytotoxicity compared to PAD in four different tumor cell lines, with the effect being similar or greater than the effect of TAT-PAD, depending upon the cell type. The mechanistic studies demonstrated that modifying CsA or TAT did not change the cytotoxicity mechanism of PAD, which occurred via mitochondrial membrane damage related to apoptosis. In vivo studies showed that CsA-PAD could achieve similar anti-tumor efficacy to TAT-PAD but with much lower systemic toxicity, especially to the heart and liver. In conclusion, our study demonstrates for the first time that the electronic-neutral penetrating peptide CsA can be used as a powerful tool to deliver peptide drugs with similar efficiency and less toxicity than the positively charged TAT peptide.
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PMID:The use of electronic-neutral penetrating peptides cyclosporin A to deliver pro-apoptotic peptide: A possibly better choice than positively charged TAT. 2866 2

HIV1-TAT interactive protein (TIP60) is a haploinsufficient tumor suppressor. However, the potential mechanisms endowing its tumor suppressor ability remain incompletely understood. It plays a vital role in virus-induced cancers where TIP60 down-regulates the expression of human papillomavirus (HPV) oncoprotein E6 which in turn destabilizes TIP60. This intrigued us to identify the role of TIP60, in the context of a viral infection, where it is targeted by oncoproteins. Through an array of molecular biology techniques such as Chromatin immunoprecipitation, expression analysis and mass spectrometry, we establish the hitherto unknown role of TIP60 in repressing the expression of the catalytic subunit of the human telomerase complex, TERT, a key driver for immortalization. TIP60 acetylates Sp1 at K639, thus inhibiting Sp1 binding to the TERT promoter. We identified that TIP60-mediated growth suppression of HPV-induced cervical cancer is mediated in part due to TERT repression through Sp1 acetylation. In summary, our study has identified a novel substrate for TIP60 catalytic activity and a unique repressive mechanism acting at the TERT promoter in virus-induced malignancies.
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PMID:TIP60 represses telomerase expression by inhibiting Sp1 binding to the TERT promoter. 2904 64

Human wings apart-like (hWAPL) is reported to have an association with cervical cancer. In the present study, the role of hWAPL in cervical cancer stem cells (CCSCs) was evaluated. Cervical tumorspheres were generated from cervical cancer tissues cultured in stem cell medium, and the expression of hWAPL by the tumorspheres was detected using immunohistochemistry. hWAPL expression levels in the tumorspheres were then upregulated using hWAPL adenoviral vectors or downregulated via the TAT-mediated knockdown of hWAPL and the effects on the tumorspheres were evaluated using colony formation, cell invasion and western blotting assays. The results demonstrated that the expression of hWAPL and human papillomavirus (HPV) was associated with the pluripotency of CCSCs, with hWAPL expression decreasing following the differentiation of cervical tumorspheres. Knockdown of hWAPL expression decreased HPV E6 expression and inhibited tumor invasion and colony formation. TAT-mediated knockdown of hWAPL with short interfering RNA significantly reduced tumor growth in nude mice. These results suggest that hWAPL is a marker of CCSC proliferation and is potentially a therapeutic target for cervical carcinoma through the downregulation of HPV E6.
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PMID:TAT-mediated si-hWAPL inhibits the invasion and metastasis of cervical cancer stem cells. 2928 75