Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0023418 (leukemia)
 93,477 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Hemophilia B is an X chromosome-linked recessive bleeding disorder. To develop a somatic gene therapy for this disease, we have examined whether mouse skeletal myoblasts can serve as efficient vehicles for systemic delivery of recombinant factor IX. When mouse myoblasts (C2C12) transduced with a Moloney murine leukemia virus-based vector containing the bacterial beta-galactosidase gene were injected into mouse skeletal muscles, they fused with the existing and regenerating myofibers and continued to express beta-galactosidase. C2C12 myoblasts that were infected with recombinant retroviruses containing a human factor IX cDNA secreted biologically active human factor IX cDNA secreted biologically active human factor IX into the culture medium at a rate of 2.6 micrograms per 10(6) cells per day. Myotubes derived from these cells in culture continued to express human factor IX (0.68 micrograms/day from myotubes derived from 10(6) C2C12 cells). After injection of the transduced C2C12 myoblasts into skeletal muscles of mice, the systemic level of recombinant human factor IX was found to be as high as approximately 1 microgram/ml of serum. These results provide the rationale for using skeletal myoblasts as an efficient gene delivery vehicle in the somatic gene therapy for hemophilia B.
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PMID:Expression of human factor IX in mice after injection of genetically modified myoblasts. 156 26

In aiming to develop a gene therapy approach for hemophilia B, we expressed and characterized human factor IX in rat capillary endothelial cells (CECs). Moloney murine leukemia virus-derived retrovirus vectors that contain human factor IX cDNA linked to heterologous promoters and the neomycin-resistant gene were constructed and employed to prepare recombinant retroviruses. Rat CECs and NIH 3T3 cells infected with these viruses were selected with the neomycin analogue, G418 sulfate, and tested for expression of factor IX. A construct with the factor IX cDNA under direct control by long terminal repeat gave the highest level of expression (0.84 and 3.6 micrograms per 10(6) cells per day for CECs and NIH 3T3 cells, respectively) as quantitated by immunoassays as well as clotting activity assays. A single RNA transcript of 4.4 kilobases predicted by the construct and a recombinant factor IX of 68 kilodaltons identical to purified plasma factor IX were found. The recombinant human factor IX produced showed full clotting activity, demonstrating that CECs have an efficient mechanism for posttranslational modifications, including gamma-carboxylation, essential for its biological activity. These results, in addition to other properties of the endothelium, including large number of cells, accessibility, and direct contact with the circulating blood, suggest that CECs can serve as an efficient drug delivery vehicle producing factor IX in a somatic gene therapy for hemophilia B.
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PMID:Expression of human factor IX in rat capillary endothelial cells: toward somatic gene therapy for hemophilia B. 189 57

A 10-year-old classic hemophiliac and 1.5-year-old child with hemophilia B who developed acute lymphocytic and acute myelomonocytic leukemia respectively are presented. No changes in coagulation status of the patients were observed. It is suggested that hemophiliacs should be regarded as "population at risk" for the development of leukemia.
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PMID:Acute leukemia in two patients with hemophilia. 385 69

Hemophilia B is an X-chromosome-linked recessive disorder that is caused by a deficiency of biologically active clotting factor IX (FIX). In this work, liposomes (Lip) were used for non-viral, in vivo gene transfer of the human FIX gene into mouse organs. Plasmid DNA, containing the human FIX cDNA under the control of the Moloney murine leukemia virus (MoMLV) long terminal repeat (LTR), was encapsulated in 1-2-microns multilamellar Lip composed of egg phosphatidylcholine (EPC). The percentage of Lip-associated DNA was 47%, and 72% of the Lip DNA was protected from DNase I digestion. The Lip-encapsulated (Len) DNA was injected intravenously into Balb/c mice, and at various times post-injection, various tissues were examined for the presence of the exogenous DNA. Plasmid DNA was detected by Southern blot analysis mainly in the liver and spleen, but small amounts were also detected in the lungs, heart and kidneys. The plasmid DNA was retained in mouse liver cells for at least 7 days post-injection, and remained in an episomal state. The levels of human FIX protein in the mouse plasma were 190-650 pg per ml for 2 to 7 days post-injection. Treatment of mice with chloroquine (Cq) and colchicine (Cc) prior to Lip injection significantly increased the amount of plasmid DNA found in the liver cells, as well as the level of human FIX in the plasma. These results demonstrate the potential use of Len DNA for gene transfer into liver and spleen, and for gene therapy of inherited and acquired disorders.
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PMID:Liposome-encapsulated DNA-mediated gene transfer and synthesis of human factor IX in mice. 766 69

Development of a highly refined human factor IX (hFIX) expression vector system is critical for establishing a durable hemophilia B gene therapy. Here we report construction of a series of retroviral vectors and identification of an optimal basic structure and components for expressing hFIX in skeletal muscle cells. These vectors, which are derived from Moloney murine leukemia virus (MoMLV) with its enhancer sequence in the 3' long terminal repeat (LTR) deleted, contained internal hFIX expression units inserted in forward configuration without or with a viral vector intron sequence (pdL or pdLIn vector frame, respectively) or in inverted configuration without a viral vector intron sequence (pdLi frame). Internal expression units contained a hFIX cDNA or hFIX minigene (hIXm1 or hIXm2) derived from the hFIX cDNA by insertion of a shortened first intron sequence of the hFIX gene. Regardless of the promoter and vector frame used, both hIXm1 and hIXm2 gave 10- to 14-fold higher hFIX expression compared to those with hFIX cDNA. Internal hFIX transcriptional control units of these vectors were composed of various promoters linked with or without the muscle creatine kinase enhancer (Me) sequence. Promoters tested included those of alpha-actin (alpha A775), beta-actin (beta A280), cytochrome oxidase (CO1250 and CO650), myogenin (Mg1031 and Mg353), and Rous sarcoma virus (RSV). beta A200, which was derived from beta A280 by eliminating potential polyadenylation sites, was also tested. As extensively examined with the myogenin promoter, presence of one or multiple copies of Me in the vectors elevated the expression activity in myotubes by 4.5- to 19-fold over those without Me, but not significantly in myoblasts. Similar enhancements in expression activity with Me were also observed with other promoters, except those of RSV and CO. The latter two showed only modest enhancements in the presence of Me. As assayed with myotubes in culture, the general order of hFIX expression activity of various promoters with four copies of Me in the three different vector frames was beta A280 approximately beta A200 > Mg353 > Mg1031 approximately RSV approximately CO650 approximately alpha A775 > CO1250. One exception was that CO650 showed significantly less activity in pdLi-type vectors than in the pdLIn vectors. Based on the systematic analyses of various structural components, a group of pdLi vectors consisting of beta A200, two to four copies of Me, and hIXm2 was identified to have the optimal basic vector structure to be used in retrovirus for hFIX expression in differentiated skeletal muscle cells. The present studies provide the critical first step for establishing a highly refined hemophilia B gene therapy based on skeletal muscle-targeted hFIX gene transfer.
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PMID:Construction of human factor IX expression vectors in retroviral vector frames optimized for muscle cells. 888 45

Hemophilia B is a bleeding disorder resulting from factor IX (FIX) deficiency that might be treated with gene therapy. Neonatal delivery would correct the disease sooner than would transfer into adults, and could reduce immunological responses. Neonatal mice were injected intravenously with a Moloney murine leukemia virus-based retroviral vector (RV) expressing canine FIX (cFIX). They achieved 150% to 280% of normal cFIX antigen levels in plasma (100% is 5 microg/mL), which was functional in vitro and in vivo. Three newborn hemophilia B dogs that were injected intravenously with RV achieved 12% to 36% of normal cFIX antigen levels, which improved coagulation tests. Only one mild bleed has occurred during 14 total months of evaluation. This is the first demonstration of prolonged expression after neonatal gene therapy for hemophilia B in mice or dogs. Most animals failed to make antibodies to cFIX, demonstrating that neonatal gene transfer may induce tolerance. Although hepatocytes from newborns replicate, those from adults do not. Adult mice therefore received hepatocyte growth factor to induce hepatocyte replication prior to intravenous injection of RV. This resulted in expression of 35% of normal cFIX antigen levels for 11 months, although all mice produced anti-cFIX antibodies. This is the first demonstration that high levels of FIX activity can be achieved with an RV in adults without a partial hepatectomy to induce hepatocyte replication. We conclude that RV-mediated hepatic gene therapy is effective for treating hemophilia B in mice and dogs, although the immune system may complicate gene transfer in adults.
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PMID:Neonatal or hepatocyte growth factor-potentiated adult gene therapy with a retroviral vector results in therapeutic levels of canine factor IX for hemophilia B. 1253 87

The past 3 years have been characterized by a number of impressive advances as well as setbacks in gene therapy for genetic disease. Children with X-linked severe combined immunodeficiency disorder (SCID-X1) have shown almost complete reconstitution of their immune system after receiving retrovirally transduced autologous CD34+ hematopoietic stem cells (HSCs). However, two of 11 treated patients subsequently developed a leukemia-like disease probablydue to the undesired activation of an oncogene. Gene transfer to HSCs resulted in substantial correction of immune function and multi-lineage engraftment in two patients with adenosine deaminase (ADA)-SCID. Several Phase I clinical trials for treatment of hemophilia A and B have been initiated or completed. Partial correction of hemophilia A, albeit transient, has been reported by ex vivo gene transfer to autologous fibroblasts. Intramuscular injection of adeno-associated viral (AAV) vector to patients with severe hemophilia B resulted in evidence of Factor IX gene transfer to skeletal muscle and a separate trial based on hepatic infusion of AAV vector is ongoing. Sustained therapeutic levels of coagulation factor expression have been achieved in preclinical models using retroviral, lentiviral, AAV and high capacity adenoviral vectors. Efficient lentiviral gene transfer to HSC in murine models of beta-thalassemia and sickle cell disease demonstrated sustained phenotypic correction.
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PMID:Update on gene therapy for hereditary hematological disorders. 1503 Feb 82