Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.5.4.1 (cytosine deaminase)
 747 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

An attempt was made to use simple cationic liposomes DC-Chol/DOPE and DDAB/DOPE (DC-Chol is 3 beta (N(N',N-dimethylaminoethane) carbamoyl) cholesterol, DDAB is dimethyldioctadecyl ammonium bromide and DOPE is dioleoylphosphatidylethanolamine) for transfer of Escherichia coli cytosine deaminase 'suicide' gene under the control of tissue-specific tyrosinase gene promoter directly into the murine melanoma B16(F10) tumor. Several repeated intratumoral injections of DNA-liposome complexes followed by intraperitoneal administrations of 5-fluorocytosine, which is converted to 5-fluorouracil, caused strong retardation of murine melanoma B16(F10) tumor growth and, in some cases, rejection of the pre-established tumor. The inhibition of tumor growth expressed as the increased survival of mice is better seen in the case of using DNA-DDAB/DOPE complexes as compared to DNA-DC-Chol/DOPE ones. It seems that the observed therapeutic effect appears to result from several factors: 5-fluorouracil generation by transfected cells, liposome toxicity (DDAB is more toxic than DC-Chol and hence more tumor cells are killed), increased transfection efficiency of surviving cancer cells (in this case DDAB is a better transfection agent than DC-Chol) and, finally, the bystander effect which causes destruction of cells untransfected with CD gene by easily diffusible 5-fluorouracil.
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PMID:The use of cationic liposomes DC-CHOL/DOPE and DDAB/DOPE for direct transfer of Escherichia coli cytosine deaminase gene into growing melanoma tumors. 904 44

This study was designed to develop a safe, effective gene therapy for disseminated melanoma. We constructed retroviral vectors containing a tyrosinase promoter-cytosine deaminase expression cassette (Tyr/CD), and demonstrated that the tyrosinase promoter conferred a selective expression of cytosine deaminase (CD) gene in B16 melanoma cells, especially when the Tyr/CD cassette inserted in 3'LTR region of a retroviral vector. In vivo gene therapy for the intraperitoneally disseminated melanoma using Tyr/CD retrovirus-producing cells and 5-fluorocytosine (5-FC) showed that retroviruses produced in situ were capable of infecting tumor xenografts and bone marrow cells in animal model, and survival rates were prolonged significantly as compared with those treated with CD2 retrovirus-producing cells and 5-FC. Importantly, the treatment-related bone marrow suppression was not observed in the former treatment, while profound bone marrow suppression was observed in the latter treatment. In vivo gene therapy using retrovirus-producing cells containing suicide gene under the control of a tissue-specific promoter and 5-FC administration is safer and more effective for the treatment of disseminated melanoma, as compared with retrovirus-producing cells containing the gene under the control of a universal promoter and 5-FC.
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PMID:A safe, effective in vivo gene therapy for melanoma using tyrosinase promoter-driven cytosine deaminase gene. 1036 76

We constructed a melanoma-specific oncolytic adenoviral vector Ad.MCDIRESE1.71Hsp3, in which the cytosine deaminase and adenoviral E1A genes linked by the IRES sequence were under the control of a mouse tyrosinase enhancer/promoter transcriptional element in the E1 region of the vector. We also inserted the human heat shock protein 70 (Hsp70) gene driven by the cytomegalovirus promoter into the E3 region of this vector. The RGD-4C peptide was inserted into the HI loop of the fiber knob domain of the Ad.MCDIRESE1.71Hsp3 vector to increase the transduction efficiency of this vector to tumor cells. The Ad.MCDIRESE1.71Hsp3 vector replicates specifically in melanoma cells, and it has a melanoma-specific cytotoxic effect in the presence of 5-fluorocytosine in vitro and in vivo. Moreover, the in vivo killing of tumor cells associated with the overexpression of Hsp70 generated by the intratumoral injection of the Ad.MCDIRESE1.71Hsp3 vector into established subcutaneous tumors can lead to the suppression of tumor growth and potent melanoma-specific systemic immune responses.
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PMID:Tumor-specific therapeutic effect induced by an oncolytic adenoviral vector containing heat shock protein 70 and prodrug activation genes. 1661

We constructed an oncolytic adenoviral vector Ad.HE1HCD3, in which the adenoviral E1A promoter was replaced by a human tyrosinase enhancer (HTE)/promoter. The RGD-4C peptide was inserted into the HI loop of the fiber knob domain to increase the transduction efficiency of this vector for tumor cell lines. We also inserted the prodrug activating cytosine deaminase gene driven by the HTE/promoter into the E3 region of the Ad.HE1HCD3 vector. The in vitro cytotoxic effect of the Ad.HE1HCD3 vector with 5-fluorocytosine (5-FC) was greater than that of a wild-type adenovirus or that of the Ad.HE1HCD3 vector alone in tyrosinase-positive melanoma cell lines at low multiplicity of infection. Intratumoral injection of low doses of the Ad.HE1HCD3 vector into xenotransplanted human melanoma cell lines followed by the intraperitoneal injection of 5-FC led to a greater degree of tumor regression in vivo than did the intratumoral injection of the same dose of the Ad.HE1HCD3 vector alone. This oncolytic vector with a melanoma-specific prodrug activation therapeutic transcription unit and a RGD targeted fiber protein offers a potent therapeutic combination for the gene therapy of melanoma.
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PMID:Oncolytic adenoviral vector carrying the cytosine deaminase gene for melanoma gene therapy. 1671 Mar 44

Key challenges facing cancer therapy are the development of tumor-specific drugs and potent multimodal regimens. Oncolytic adenoviruses possess the potential to realize both aims by restricting virus replication to tumors and inserting therapeutic genes into the virus genome, respectively. A major effort in this regard is to express transgenes in a tumor-specific manner without affecting virus replication. Using both luciferase as a sensitive reporter and genetic prodrug activation, we show that promoter control of E1A facilitates highly selective expression of transgenes inserted into the late transcription unit. This, however, required multistep optimization of late transgene expression. Transgene insertion via internal ribosome entry site (IRES), splice acceptor (SA), or viral 2A sequences resulted in replication-dependent expression. Unexpectedly, analyses in appropriate substrates and with matching control viruses revealed that IRES and SA, but not 2A, facilitated indirect transgene targeting via tyrosinase promoter control of E1A. Transgene expression via SA was more selective (up to 1,500-fold) but less effective than via IRES. Notably, we also revealed transgene-dependent interference with splicing. Hence, the prodrug convertase FCU1 (a cytosine deaminase-uracil phosphoribosyltransferase fusion protein) was expressed only after optimizing the sequence surrounding the SA site and mutating a cryptic splice site within the transgene. The resulting tyrosinase promoter-regulated and FCU1-encoding adenovirus combined effective oncolysis with targeted prodrug activation therapy of melanoma. Thus, prodrug activation showed potent bystander killing and increased cytotoxicity of the virus up to 10-fold. We conclude that armed oncolytic viruses can be improved substantially by comparing and optimizing strategies for targeted transgene expression, thereby implementing selective and multimodal cancer therapies.
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PMID:Selectivity and efficiency of late transgene expression by transcriptionally targeted oncolytic adenoviruses are dependent on the transgene insertion strategy. 2148 59

In preparation of the therapeutic genetic constructs aimed to the gene-programmed enzymatic transformation of the non-toxic prodrug into toxin within cancer cells the right choice of regulatory elements (promoters and enhancers) is essential. This is widely accepted that the efficiency of the gene therapy constructions is dependent, in particular, on the strength of promoters driving the expression of the therapeutic genes. In this work we demonstrated, using the melanoma-specific promoters and enhancers of human melanoma inhibitory activity and mouse tyrosinase gene, that for the development of cytotoxic effect the promoter strength is not of primary importance. In the case of HSVtk, coding for the herpes simplex virus thymidine kinase, and FCU1, coding for cytosine deaminase/uracil phosphoribosyltransferase hybrid protein genes, their cytotoxic activity was determined by the quantity of the added prodrug.
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PMID:[Cytotoxicity of cytosine deaminase and herpes simplex virus thymidine kinase genes in melanoma cells is independent on promoter strength]. 2569 36