title: Correcting miR-15a/16 genetic defect in New Zealand Black mouse model of CLL enhances drug sensitivity.
abstract: Alterations in the human 13q14 genomic region containing microRNAs mir-15a and mir-16-1 are present in most human chronic lymphocytic leukemia (CLL). We have previously found the development of CLL in the New Zealand Black murine model to be associated with a point mutation in the primary mir-15a/16-1 region, which correlated with a decrease in mature miR-16 and miR-15a levels. In this study, addition of exogenous miR-15a and miR-16 led to an accumulation of cells in G(1) in non-New Zealand Black B cell and New Zealand Black-derived malignant B-1 cell lines. However, the New Zealand Black line had significantly greater G(1) accumulation, suggesting a restoration of cell cycle control upon exogenous miR-15a/16 addition. Our experiments showed a reduction in protein levels of cyclin D1, a miR-15a/16 target and cell cycle regulator of G(1)/S transition, in the New Zealand Black cell line following miR-15a/16 addition. These microRNAs were shown to directly target the cyclin D1 3' untranslated region using a green fluorescent protein lentiviral expression system. miR-16 was also shown to augment apoptosis induction by nutlin, a mouse double minute 2 (MDM2) antagonist, and genistein, a tyrosine kinase inhibitor, when added to a B-1 cell line derived from multiple in vivo passages of malignant B-1 cells from New Zealand Black mice with CLL. miR-16 synergized with nutlin and genistein to induce apoptosis. Our data support a role for the mir-15a/16-1 cluster in cell cycle regulation and suggest that these mature microRNAs in both the New Zealand Black model and human CLL may be targets for therapeutic efficacy in this disease.
authors.affiliation: Pathology and Laboratory Medicine, New Jersey Medical School, MSB C512, Newark, NJ 07103, USA.
authors.forename: Erica
authors.initials: E
authors.lastname: Salerno
authors.forename: Brian J
authors.initials: BJ
authors.lastname: Scaglione
authors.forename: Frederick D
authors.initials: FD
authors.lastname: Coffman
authors.forename: Brian D
authors.initials: BD
authors.lastname: Brown
authors.forename: Alessia
authors.initials: A
authors.lastname: Baccarini
authors.forename: Helen
authors.initials: H
authors.lastname: Fernandes
authors.forename: Gerald
authors.initials: G
authors.lastname: Marti
authors.forename: Elizabeth S
authors.initials: ES
authors.lastname: Raveche
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology; D017209:Apoptosis; D001483:Base Sequence; D019938:Cyclin D1 / Q000235:genetics; D017931:DNA Primers; D004195:Disease Models, Animal; D004354:Drug Screening Assays, Antitumor; D019833:Genistein / Q000627:therapeutic use; D007093:Imidazoles / Q000627:therapeutic use; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000188:drug therapy / Q000235:genetics* / Q000473:pathology; D051379:Mice; D008810:Mice, Inbred C57BL; D035683:MicroRNAs / Q000235:genetics*; D010879:Piperazines / Q000627:therapeutic use; D012333:RNA, Messenger / Q000235:genetics
chemical_list: D000970:Antineoplastic Agents; D017931:DNA Primers; D007093:Imidazoles; D035683:MicroRNAs; D010879:Piperazines; D012333:RNA, Messenger; D019938:Cyclin D1; C482205:nutlin 3; D019833:Genistein