title: Positive selection of gene-modified cells increases the efficacy of pancreatic cancer suicide gene therapy.
abstract: Thymidine kinase (TK)-mediated suicide gene therapy has been considered for the treatment of pancreatic cancer. However, despite a bystander effect, the proportion of transduced tumor cells has proven too low to result in efficacy. We propose the use of a drug-selectable marker (MDR1) to enrich TK-expressing cells using chemotherapy. This enrichment or positive selection phase may increase the efficacy of suicide gene therapy. To test this strategy, we generated stable NP18MDR/TK-GFP transfectants and showed docetaxel resistance in vivo. Mixed tumors of MDR/TK-expressing cells and parental NP18 cells were established and docetaxel was used to increase the proportion of TK-expressing cells. After this positive selection phase, suicide gene therapy with ganciclovir was applied. Upon positive selection, the proportion of TK-expressing cells increased from 4% to 22%. Subsequent suicide gene therapy was more effective compared with a control group without positive selection. Starting with 10% of TK-expressing cells the positive-negative selection strategy completely inhibited tumor growth. Taken together, these results suggest that a positive-negative selection strategy based on MDR and TK genes represents an efficient way to increase the proportion of TK-expressing cells in the tumor and the efficacy of TK-mediated suicide gene therapy.
authors.affiliation: Gene and Viral Therapy Group, IDIBELL-Catalan Institute of Oncology (ICO), L'Hospitalet de Llobregat, UPF, Parc de Recerca Biomédica de Barcelona and Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER-ISCIII), Barcelona, Spain.
authors.forename: Jordi
authors.initials: J
authors.lastname: Martinez-Quintanilla
authors.forename: Manel
authors.initials: M
authors.lastname: Cascallo
authors.forename: Alena
authors.initials: A
authors.lastname: Gros
authors.forename: Cristina
authors.initials: C
authors.lastname: Fillat
authors.forename: Ramon
authors.initials: R
authors.lastname: Alemany
mesh_terms: D018435:ATP Binding Cassette Transporter, Subfamily B; D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism; D000230:Adenocarcinoma / Q000235:genetics / Q000628:therapy; D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology; D045744:Cell Line, Tumor; D003131:Combined Modality Therapy; D000077143:Docetaxel; D015774:Ganciclovir / Q000494:pharmacology*; D041722:Genes, Transgenic, Suicide; D015316:Genetic Therapy / Q000379:methods*; D005822:Genetic Vectors; D006801:Humans; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D010190:Pancreatic Neoplasms / Q000188:drug therapy / Q000235:genetics* / Q000628:therapy*; D043823:Taxoids / Q000494:pharmacology*; D013937:Thymidine Kinase / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism; D014162:Transfection; D023041:Xenograft Model Antitumor Assays
chemical_list: C513055:ABCB1 protein, human; D018435:ATP Binding Cassette Transporter, Subfamily B; D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000970:Antineoplastic Agents; D043823:Taxoids; D000077143:Docetaxel; D013937:Thymidine Kinase; D015774:Ganciclovir