Modulation of the typical multidrug resistance phenotype by targeting the MED-1 region of human MDR1 promoter

• Published in: Gene therapy Vol. 7; no. 14; pp. 1224 - 1233
• Main Authors: MARTHINET, E, DIVITA, G, BERNAUD, J, RIGAL, D, BAGGETTO, L
• Format: Journal Article
• Language: English
• Published: Basingstoke Nature Publishing Group 01.07.2000
• Subjects: Antisense therapy; Antitumor agents; ATP-Binding Cassette, Sub-Family B, Member 1 - genetics; Biological and medical sciences; Biotechnology; Chemotherapy; Drug Resistance, Multiple - genetics; Endodeoxyribonucleases - genetics; Fundamental and applied biological sciences. Psychology; Gene therapy; Genes, MDR - genetics; Genetic Vectors; Genotype & phenotype; Health. Pharmaceutical industry; Humans; Industrial applications and implications. Economical aspects; MDR1 gene; MDR1 protein; Membrane proteins; Multidrug resistance; Multidrug resistant organisms; Oligonucleotides; P-Glycoprotein; Phenotype; Phenotypes; Precursor Cell Lymphoblastic Leukemia-Lymphoma - drug therapy; Precursor Cell Lymphoblastic Leukemia-Lymphoma - genetics; Promoter Regions, Genetic - genetics; Transcription; Transfection; Tumor Cells, Cultured; Vinblastine; Human; Drug; Chemotherapy; Phenotype; Targeting; Peptides; Multiple resistance; Glycoprotein; Malignant tumor; Gene therapy; Vector
• ISSN: 0969-7128; 1476-5462
• DOI: 10.1038/sj.gt.3301231

Multidrug resistance of cancer (MDR) is the major cause of failure of chemotherapy. The typical MDR phenotype is due to the overexpression of membrane proteins among which the main representative is P-glycoprotein (Pgp) encoded by the MDR1 gene. Many attempts to modulate MDR by chemosensitizers have been unsuccessful in human therapy due to their intrinsic toxic effects. In an effort to modulate the MDR phenotype efficiently we designed an antisense and a transcriptional decoy strategy targeting the TATA-less human MDR1 gene promoter. The choice of the start point of transcription in a multiple start site window is related to an upstream MED-1 cis-element, the sequence and configuration of which are specific to human MDR1 gene expressed in Pgp-overproducing cancer cells. A 12mer antisense oligodeoxynucleotide (ODN) and a 12mer double-stranded ODN, both containing the MED-1 sequence, were designed and efficiently vectorized into the nucleus with the chimerical MPG peptide. A synthetic cellular model (NIH-EGFP) and highly resistant human CEM/VLB0.45 leukemia cells, significantly responded to transfection with the ODN/MPG complex. The level of EGFP fluorescence in NIH-EGFP cells decreased, and thus its production, and viability of CEM/VLB0.45 cells decreased by 63% in the presence of vinblastine, revealing that their resistance to the anticancer drug was reversed. These results open new insights into transcriptional decoy and anti-gene therapies of MDR cancers that overproduce Pgp. Gene Therapy (2000) 7, 1224-1233.