A mutated PML/RARA found in the retinoid maturation resistant NB4 subclone, NB4-R2, blocks RARA and wild-type PML/RARA transcriptional activities

• Published in: Leukemia Vol. 14; no. 2; pp. 255 - 261
• Main Authors: DUPREZ, E, BENOIT, G, FLEXOR, M, LILLEHAUG, I. R, LANOTTE, M
• Format: Journal Article
• Language: English
• Published: London Nature Publishing 01-02-2000; Nature Publishing Group
• Subjects: Acute promyeloid leukemia; Amino acid sequence; Amino acids; Antibodies; Antineoplastic agents; Biological and medical sciences; Chemotherapy; Cloning; Codon - genetics; Defects; Fluorescent Antibody Technique; Fusion protein; Gene Expression Regulation, Neoplastic - genetics; HeLa Cells; Hematologic and hematopoietic diseases; Humans; Leukemia; Leukemia, Promyelocytic, Acute - genetics; Leukemias. Malignant lymphomas. Malignant reticulosis. Myelofibrosis; Leukemogenesis; Ligands; Luciferases - analysis; Medical sciences; Microscopy, Confocal; Mutation; Neoplasm Proteins - genetics; Oncogene Proteins, Fusion - genetics; Pharmacology. Drug treatments; Plasmids; PML protein; Polymerase Chain Reaction; Promyeloid leukemia; Proteins; RARA protein; Receptors, Retinoic Acid - genetics; Remission (Medicine); Retinoic acid; Retinoic Acid Receptor alpha; Sensitivity; Sequence Analysis, RNA; Stop codon; Transcription; Transcription, Genetic; Tretinoin - metabolism; France; Paris France; Chromosomal aberration; Antineoplastic agent; Human; Promyelocytic leukemia; Acute; Malignant hemopathy; In vitro; Established cell line; Cytogenetics; Abnormal chromosome; Genetics; Mutation; Fusion protein; Negative therapeutic reaction; Retinoic acid; Hybrid gene; Biological receptor; Chromosome translocation
• ISSN: 0887-6924; 1476-5551
• DOI: 10.1038/sj.leu.2401683

The fusion protein PML/RARA, associated with acute promyelocytic leukemia behaves as an abnormal retinoic acid (RA) receptor with altered transactivation properties but is still inducible by RA. The chimeric protein is thought to promote leukemogenesis but also paradoxically to mediate the sensitivity to ATRA of APL cells. This has been supported by works reporting that in vitro ATRA resistance is characterized by defects in the RARA/E-domain of PML/RARA. In the present report, we identified a new mutation in the E domain of PML/RARA which is associated with a RA-resistant subline of NB4 cells; NB4-R2. This mutation, identical to the Gln411 mutation found in HL60-R, changes the amino acid Gln903 to an in-phase stop codon, generating a truncated form of PML/RARA which has lost 52 amino acids at its C-terminal end. We have studied the effect of the truncated PML/RARA protein on PML NB formation and RARA and PML/RARA transcriptional activity. We show here that the fusion mutant exerts a dominant negative effect on wild-type PML, PML/RARA and RARA transcription activity. These findings highlight the important role of the RARA E-domain of PML/RARA in mediating RA sensitivity in APL cells.