Co-expression of the herpes simplex virus thymidine kinase gene potentiates methotrexate resistance conferred by transfer of a mutated dihydrofolate reductase gene Journal Article

  

Authors:	Mineishi, S.; Nakahara, S.; Takebe, N.; Banerjee, D.; Zhao, S. C.; Bertino, J. R.
Article Title:	Co-expression of the herpes simplex virus thymidine kinase gene potentiates methotrexate resistance conferred by transfer of a mutated dihydrofolate reductase gene
Abstract:	We have previously shown that transfer of a mutated dihydrofolate reductase (DHFR) confers resistance to methotrexate (MTX) to infected cells. We report herein the construction of a retrovirus vector, DC/SV6S31tk, which carries the herpes simplex virus thymidine kinase gene (HSVtk) as well as the mutated Serine 31 DHFR (S31) cDNA. 3T3 cells infected with DC/SV6S31tk are more resistant to MTX than cells infected with DC/SV6S31, which carries the S31 and Neo1 gene. In DC/SV6S31tk-infected cells, a fraction of cells (20-40%) were more resistant to MTX compared with DC/SV6S31-infected cells, and these cells survived a 5-day exposure to 200 μM of MTX. The mechanism of this augmented resistance is attributed to the salvage of thymidine by HSVtk, as the augmentation is reversed when dialyzed serum is used for cytotoxicity assays. The cells that survive high-dose MTX selection have high levels of expression of S31 DHFR and HSVtk, although copy numbers of the proviral sequences do not increase significantly. Transduction of cells with the DC/SV6S31tk vector also sensitizes cells to ganciclovir (GCV). Co-expression of a metabolically related gene in a retroviral vector to potentiate the resistance imparted by a drug resistance gene may be useful for gene therapy for cancer patients.
Keywords:	gene mutation; mutation; nonhuman; methotrexate; animal cell; mouse; animals; mice; bone marrow cells; gene expression; antimetabolites, antineoplastic; serine; drug resistance; drug resistance, neoplasm; mice, inbred c57bl; genetic transduction; animalia; genetic vectors; gene therapy; simplexvirus; thymidine kinase; dihydrofolate reductase; tetrahydrofolate dehydrogenase; herpes simplex virus; herpes; ganciclovir; retrovirus; retroviridae; 3t3 cells; antiviral agents; gene transfer techniques; coculture techniques; drug sensitization; cloning vector; unidentified retrovirus; cancer; male; priority journal; article; neopterin
Journal Title:	Gene Therapy
Volume:	4
Issue:	6
ISSN:	0969-7128
Publisher:	Nature Publishing Group
Date Published:	1997-06-01
Start Page:	570
End Page:	576
Language:	English
PUBMED:	9231073
PROVIDER:	scopus
DOI:	10.1038/sj.gt.3300439
DOI/URL:	https://www.scopus.com/inward/record.uri?eid=2-s2.0-0030811863&partnerID=40&md5=730fc438cae394423a4d8f41449a208d
Notes:	Article -- Export Date: 17 March 2017 -- Source: Scopus

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