Targeted expression of human folylpolyglutamate synthase for selective enhancement of methotrexate chemotherapy in osteosarcoma cells
Department of Neurology, Gene Therapy Center
Medical Subject Headings
Antimetabolites, Antineoplastic; Bone Neoplasms; Cell Line, Tumor; Cloning, Molecular; Gene Expression; Gene Order; Genes, Reporter; Genetic Vectors; Humans; Lentivirus; Methotrexate; Organ Specificity; Osteocalcin; Osteosarcoma; Peptide Synthases; Promoter Regions, Genetic; Transduction, Genetic; Transfection; Tumor Cells, Cultured
Cancer Biology | Genetics | Heterocyclic Compounds | Medicinal Chemistry and Pharmaceutics | Neoplasms | Therapeutics
The antifolate methotrexate (MTX) is an important chemotherapeutic agent for treatment of osteosarcoma. This drug is converted intracellularly into polyglutamate derivates by the enzyme folylpolyglutamate synthase (FPGS). MTX polyglutamates show an enhanced and prolonged cytotoxicity in comparison to the monoglutamate. In the present study, we proved the hypothesis that transfer of the human fpgs gene into osteosarcoma cells may augment their MTX sensitivity. For this purpose, we employed the human osteocalcin (OC) promoter, which had shown marked osteosarcoma specificity in promoter studies using different luciferase assays in osteosarcoma and non-osteosarcoma cell lines. A recombinant lentiviral vector was generated with the OC promoter driving the expression of fpgs and the gene for enhanced green fluorescent protein (egfp), which was linked to fpgs by an internal ribosomal entry site (IRES). As the vector backbone contained only a self-inactivating viral LTR promoter, any interference of the OC promoter by unspecific promoter elements was excluded. We tested the expression of FPGS and enhanced green fluorescent protein (EGFP) after lentiviral transduction in various osteosarcoma cell lines (human MG-63 cells and TM 791 cells; rat osteosarcoma (ROS) 17/2.8 cells) and non-osteogenic tumor cell lines (293T human embryonic kidney cells, HeLa human cervix carcinoma cells). EGFP expression and MTX sensitivity were assessed in comparison with non-transduced controls. Whereas the OC promoter failed to enhance MTX sensitivity via FPGS expression in non-osteogenic tumor cell lines, the OC promoter mediated a markedly increased MTX cytotoxicity in all osteosarcoma cell lines after lentiviral transduction. The present chemotherapy-enhancing gene therapy system may have great potential to overcome in future MTX resistance in human osteosarcomas.
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Citation: Cancer Gene Ther. 2013 Sep;20(9):514-20. doi: 10.1038/cgt.2013.48. Epub 2013 Aug 16. Link to article on publisher's site
Bienemann, K.; Staege, M. S.; Howe, S. J.; Sena-Esteves, Miguel; Hanenberg, H.; and Kramm, C. M., "Targeted expression of human folylpolyglutamate synthase for selective enhancement of methotrexate chemotherapy in osteosarcoma cells" (2013). University of Massachusetts Medical School Faculty Publications. 560.