@article {1729, title = {miR-34a induces the downregulation of both E2F1 and B-Myb oncogenes in leukemic cells.}, journal = {Clin Cancer Res}, volume = {17}, year = {2011}, month = {2011 May 1}, pages = {2712-24}, abstract = {

PURPOSE: To elucidate new molecular mechanisms able to downregulate the mRNA levels of key oncogenes, such as B-Myb and E2F1, in a therapeutic perspective.

EXPERIMENTAL DESIGN: B-Myb and E2F1 mRNA levels were evaluated in primary B chronic lymphocytic leukemia (B-CLL, n = 10) and acute myeloid leukemia (AML, n = 5) patient cells, in a variety of p53(wild-type) and p53(mutated/deleted) leukemic cell lines, as well as in primary endothelial cells and fibroblasts. Knockdown experiments with siRNA for p53 and E2F1 and overexpression experiments with miR34a were conducted to elucidate the role of these pathways in promoting B-Myb downregulation.

RESULTS: In vitro exposure to Nutlin-3, a nongenotoxic activator of p53, variably downregulated the expression of B-Myb in primary leukemic cells and in p53(wild-type) myeloid (OCI, MOLM) and lymphoblastoid (SKW6.4, EHEB) but not in p53(mutated) (NB4, BJAB, MAVER) or p53(deleted) (HL-60) leukemic cell lines. The transcriptional repression of B-Myb was also observed in primary normal endothelial cells and fibroblasts. B-Myb downregulation played a critical role in the cell-cycle block in G(1) phase induced by Nutlin-3, as shown by transfection experiments with specific siRNA. Moreover, we have provided experimental evidence suggesting that miR-34a is a central mediator in the repression of B-Myb both directly and through E2F1.

CONCLUSIONS: Owing to the role of B-Myb and E2F1 transcription factors in controlling cell-cycle progression of leukemic cells, the downregulation of these oncogenes by miR-34a suggests the usefulness of therapeutic approaches aimed to modulate the levels of miR-34a.

}, keywords = {Base Sequence, Cell Cycle Proteins, Cell Line, Tumor, Cells, Cultured, Down-Regulation, E2F1 Transcription Factor, Gene Expression Regulation, Leukemic, HCT116 Cells, HL-60 Cells, Humans, Imidazoles, Leukemia, MicroRNAs, Models, Biological, Oncogenes, Piperazines, Sequence Homology, Nucleic Acid, Trans-Activators, Transfection}, issn = {1078-0432}, doi = {10.1158/1078-0432.CCR-10-3244}, author = {Zauli, Giorgio and Voltan, Rebecca and di Iasio, Maria Grazia and Bosco, Raffaella and Melloni, Elisabetta and Sana, Maria Elena and Secchiero, Paola} } @article {1758, title = {Molecular targets for selective killing of TRAIL-resistant leukemic cells.}, journal = {Expert Opin Ther Targets}, volume = {15}, year = {2011}, month = {2011 Aug}, pages = {931-42}, abstract = {

INTRODUCTION: TNF-related apoptosis-inducing ligand (TRAIL) is a member of the TNF family of cytokines, and shows promising therapeutic activity against solid tumors and lymphomas, in a variety of Phase I and II clinical trials. In contrast, primary leukemias have shown poor susceptibility to TRAIL-mediated cytotoxicity, suggesting the need for sensitizing TRAIL-resistant leukemic cells, by combining soluble recombinant TRAIL either with chemotherapeutic drugs, or with targeted small molecules.

AREAS COVERED: This review discusses potential therapeutic applications of combinations able to restore the sensitivity of leukemic cells to either recombinant TRAIL or anti-TRAIL-receptor agonistic antibodies for the treatment of hematological malignancies.

EXPERT OPINION: Up-to-date knowledge of the most innovative anti-leukemic therapies including functional screening of specific-sensitizers, enhancing TRAIL-mediated cytotoxicity. Strategies aimed to enhance TRAIL-mediated apoptosis, include the combination of novel sensitizers, functionally identified from libraries of pharmaceutically active, synthetic or naturally derived compounds. Other approaches aim to employ the administration of stem cells engineered to express TRAIL, in the leukemic stem cell niche, and promise to be a successful treatment with reduced specific toxicity.

}, keywords = {Humans, Leukemia, TNF-Related Apoptosis-Inducing Ligand}, issn = {1744-7631}, doi = {10.1517/14728222.2011.580278}, author = {Zauli, Giorgio and Bosco, Raffaella and Secchiero, Paola} }