title: Dual agent chemoprotection by retroviral co-expression of either MDR1 or MRP1 with the P140K mutant of O6-methylguanine-DNA-methyl transferase.
abstract: Tumour resistance to chemotherapeutic agents results in most chemotherapy being administered in a multi-agent fashion that is often associated with a high level of toxicity in highly proliferative tissues such as the haematopoietic compartment. Thus, whilst many genetic manipulation strategies aim to protect normal tissue against a single component of a multi-agent regime, it is clearly preferable to protect normal cells against all toxicities. In this study we have used retroviral gene transfer to achieve co-expression of either p-glycoprotein (MDR1) or multi-drug resistance-related protein 1 (MRP1) with the P140K mutant form of O6-methylguanine-DNA-methyl transferase (MGMT) which, unlike the wild-type protein, is insensitive to inactivation by tumour sensitisers such as O6-benzylguanine (O6-BeG) or PaTrin2. The combination of certain MDR1/MRP1 substrate drugs with O6-alkylating agents (against which MGMT confers resistance) is particularly myelotoxic. We show here that haematopoietic progenitors co-expressing mutant MGMT with an ABC-transporter exhibit resistance to combination chemotherapy in vitro. This combination of drug transporter and DNA repair function may provide an effective in vivo protection of the haematopoietic compartment during tumour ablation using combination chemotherapy.
authors.affiliation: Cancer Research UK Gene Therapy Group, Paterson Institute for Cancer Research, Christie Hospital NHS Trust, Wilmslow Road, Manchester M20 4BX, UK. Tsouthgate@picr.man.ac.uk
authors.forename: Thomas D
authors.initials: TD
authors.lastname: Southgate
authors.forename: Elloise
authors.initials: E
authors.lastname: Garside
authors.forename: Geoffrey P
authors.initials: GP
authors.lastname: Margison
authors.forename: Leslie J
authors.initials: LJ
authors.lastname: Fairbairn
mesh_terms: D016475:3T3 Cells; D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D018906:Antineoplastic Agents, Alkylating / Q000494:pharmacology / Q000627:therapeutic use; D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology / Q000627:therapeutic use; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000494:pharmacology* / Q000627:therapeutic use; D002330:Carmustine / Q000494:pharmacology / Q000627:therapeutic use; D018432:Drug Resistance, Multiple / Q000235:genetics*; D019008:Drug Resistance, Neoplasm / Q000235:genetics*; D005047:Etoposide / Q000494:pharmacology / Q000627:therapeutic use; D015870:Gene Expression; D018014:Gene Transfer Techniques; D019450:Genes, MDR; D049452:Green Fluorescent Proteins / Q000378:metabolism; D006412:Hematopoietic Stem Cells / Q000187:drug effects / Q000201:enzymology / Q000502:physiology; D006801:Humans; D066298:In Vitro Techniques; D020014:K562 Cells; D051379:Mice; D027425:ATP-Binding Cassette, Sub-Family C Proteins / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D019853:O(6)-Methylguanine-DNA Methyltransferase / Q000235:genetics* / Q000378:metabolism; D012190:Retroviridae / Q000235:genetics; D014161:Transduction, Genetic
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D018906:Antineoplastic Agents, Alkylating; D000972:Antineoplastic Agents, Phytogenic; D002330:Carmustine; D005047:Etoposide; D049452:Green Fluorescent Proteins; D027425:ATP-Binding Cassette, Sub-Family C Proteins; D019853:O(6)-Methylguanine-DNA Methyltransferase; C421109:multidrug resistance-associated protein 1