@article {7729, title = {The anti-leukemic activity of sodium dichloroacetate in p53mutated/null cells is mediated by a p53-independent ILF3/p21 pathway.}, journal = {Oncotarget}, volume = {6}, year = {2015}, month = {2015 Feb 10}, pages = {2385-96}, abstract = {

B-chronic lymphocytic leukemia (B-CLL) patients harboring p53 mutations are invariably refractory to therapies based on purine analogues and have limited treatment options and poor survival. Having recently demonstrated that the mitochondria-targeting small molecule sodium dichloroacetate (DCA) exhibits anti-leukemic activity in p53wild-type B-CLL cells, the aim of this study was to evaluate the effect of DCA in p53mutated B-CLL cells and in p53mutated/null leukemic cell lines. DCA exhibited comparable cytotoxicity in p53wild-type and p53mutated B-CLL patient cell cultures, as well as in p53mutated B leukemic cell lines (MAVER, MEC-1, MEC-2). At the molecular level, DCA promoted the transcriptional induction of p21 in all leukemic cell types investigated, including p53null HL-60. By using a proteomic approach, we demonstrated that DCA up-regulated the ILF3 transcription factor, which is a known regulator of p21 expression. The role of the ILF3/p21 axis in mediating the DCA anti-leukemic activity was underscored by knocking-down experiments. Indeed, transfection with ILF3 and p21 siRNAs significantly decreased both the DCA-induced p21 expression and the DCA-mediated cytotoxicity. Taken together, our results emphasize that DCA is a small molecule that merits further evaluation as a therapeutic agent also for p53mutated leukemic cells, by acting through the induction of a p53-independent pathway.

}, issn = {1949-2553}, doi = {10.18632/oncotarget.2960}, author = {Agnoletto, Chiara and Brunelli, Laura and Melloni, Elisabetta and Pastorelli, Roberta and Casciano, Fabio and Rimondi, Erika and Rigolin, Gian Matteo and Cuneo, Antonio and Secchiero, Paola and Zauli, Giorgio} } @article {8097, title = {Design, Synthesis, and Biological Characterization of Novel Mitochondria Targeted Dichloroacetate-Loaded Compounds with Antileukemic Activity.}, journal = {J Med Chem}, year = {2015}, month = {2015 Dec 23}, abstract = {

The mitochondrial kinase inhibitor dichloroacetate (DCA) has recently received attention in oncology due to its ability to target glycolysis. However, DCA molecule exhibits poor bioavailability and cellular uptake with limited ability to reach its target mitochondria. To overcome these biases, we have synthesized novel DCA-loaded compounds. The selection of the most promising therapeutic molecule was evaluated by combining in vitro assays, to test the antitumoral potential on leukemic cells, and a preliminary characterization of the molecule stability in vivo, in mice. Among the newly synthesized compounds, we have selected the multiple DCA-loaded compound 10, characterized by a tertiary amine scaffold, because it exhibited enhanced (>30-fold) in vitro antitumor activity with respect to DCA and increased in vivo stability. On the basis of these results, we believe that compound 10 should be considered for further preclinical evaluations for the treatment of cancers and/or other diseases characterized by altered metabolic origin.

}, issn = {1520-4804}, doi = {10.1021/acs.jmedchem.5b01165}, author = {Trapella, Claudio and Voltan, Rebecca and Melloni, Elisabetta and Tisato, Veronica and Celeghini, Claudio and Bianco, Sara and Fantinati, Anna and Salvadori, Severo and Guerrini, Remo and Secchiero, Paola and Zauli, Giorgio} } @article {8071, title = {Kinetic Profiles of Inflammatory Mediators in the Conjunctival Sac Fluid of Patients upon Photorefractive Keratectomy.}, journal = {Mediators Inflamm}, volume = {2015}, year = {2015}, month = {2015}, pages = {942948}, abstract = {

Photorefractive keratectomy (PRK) represents a therapeutic option to remodel corneal stroma and to compensate refractive errors, which involves inflammatory and/or regenerative processes. In this context, the modulation of cytokines/chemokines in the conjunctival sac fluid and their role in the maintenance of the corneal microenvironment during the healing process upon refractive procedures has not been deeply investigated. In this study, serial samples of conjunctival sac fluid of patients (n = 25) undergoing PRK were harvested before and at different time points after surgery. The levels of 29 cytokines/chemokines/growth factors involved in inflammatory/immune processes were measured with a multiplex array system. The results have firstly highlighted the different pattern of cytokine expression between the microenvironment at the anterior surface of the eye and the systemic circulation. More importantly, the kinetic of modulation of cytokines/chemokines at the conjunctival level following PRK revealed that while the majority of cytokines/chemokines showed a significant decrease, MCP-1 emerged in light of its pronounced and significant increase soon after PRK and during the follow-up. This methodological approach has highlighted the role of MCP-1 in the healing process following PRK and has shown a potential for the identification of expression/modulation of soluble factors for biomarker profiling in ocular surface diseases.

}, issn = {1466-1861}, doi = {10.1155/2015/942948}, author = {Tisato, Veronica and Perri, Paolo and Rimondi, Erika and Melloni, Elisabetta and Lamberti, Giuseppe and Milani, Daniela and Secchiero, Paola and Zauli, Giorgio} } @article {3543, title = {Inverse correlation between circulating levels of TNF-related apoptosis-inducing ligand and 17β-estradiol.}, journal = {J Clin Endocrinol Metab}, volume = {99}, year = {2014}, month = {2014 Apr}, pages = {E659-64}, abstract = {

CONTEXT: The regulation of the circulating levels of TNF-related apoptosis-inducing ligand (TRAIL), a cytokine of the TNF family, playing a key role in the immune surveillance against cancer, is incompletely understood.

OBJECTIVE: The objective of the study was to investigate the potential link between TRAIL and 17β-estradiol.

DESIGN, SETTING, AND PARTICIPANTS: Circulating TRAIL levels were measured by an ELISA in plasma samples (n = 246) of healthy, age-matched (range 30-70 y) men and women and in the sera (n = 180) of females belonging to different physiopathological conditions (childhood, pregnancy, under gonadotropin treatment, menopause) characterized by different levels of circulating 17β-estradiol.

RESULTS: TRAIL plasma levels in women with aged younger than 50 years were significantly lower compared with age-matched men, whereas in woman 50 years old or older, TRAIL levels were significantly higher compared with the age-matched men and with the younger women. Moreover, an analysis of women with different conditions revealed a significant inverse correlation between the serum levels of TRAIL and 17β-estradiol, with the lowest levels of TRAIL being observed during pregnancy and the highest in childhood and in postmenopausal women. Moreover, gonadotropin treatment in women undergoing assisted reproduction was accompanied by an acute decrease of serum TRAIL levels. Finally, in vitro treatment with 17β-estradiol decreased the TRAIL expression levels in peripheral blood mononuclear cells.

CONCLUSIONS: Our data suggest that 17β-estradiol plays a role in regulating TRAIL circulating levels. The demonstration that postmenopausal women exhibit the highest TRAIL levels is of particular interest in light of a previous large study population showing that TRAIL is positively correlated to the overall survival.

}, keywords = {Adult, Aged, Case-Control Studies, Child, Child, Preschool, Estradiol, Female, Humans, Infant, Male, Middle Aged, Pregnancy, Sex Factors, TNF-Related Apoptosis-Inducing Ligand, Young Adult}, issn = {1945-7197}, doi = {10.1210/jc.2013-4193}, author = {Zauli, Giorgio and Tisato, Veronica and Melloni, Elisabetta and Volpato, Stefano and Cervellati, Carlo and Bonaccorsi, Gloria and Radillo, Oriano and Marci, Roberto and Secchiero, Paola} } @article {8098, title = {The p53 transcriptional pathway is preserved in ATMmutated and NOTCH1mutated chronic lymphocytic leukemias.}, journal = {Oncotarget}, volume = {5}, year = {2014}, month = {2014 Dec 30}, pages = {12635-45}, abstract = {

By using next generation sequencing, we have analyzed 108 B chronic lymphocytic leukemia (B-CLL) patients. Among genes involved in the TP53 pathway, we found frequent mutations in ATM (n=18), TP53 (n=10) and NOTCH1 (n=10) genes, rare mutations of NOTCH2 (n=2) and CDKN1A/p21 (n=1) and no mutations in BAX, MDM2, TNFRSF10A and TNFRSF10B genes. The in vitro treatment of primary B-CLL cells with the activator of p53 Nutlin-3 induced the transcription of p53 target genes, without significant differences between the B-CLL without mutations and those harboring either ATM or NOTCH1mutations. On the other hand, the subgroup of TP53mutated B-CLL exhibited a significantly lower induction of the p53 target genes in response to Nutlin-3 as compared to the other B-CLL samples. However, among the TP53mutated B-CLL, those showing mutations in the high hot spot region of the DNA binding domain [273-280 aa] maintained a significantly higher p53-dependent transcriptional activity as compared to the other TP53mutated B-CLL samples. Since the ability to elicit a p53-dependent transcriptional activity in vitro has a positive prognostic significance, our data suggest that ATMmutated, NOTCH1mutated and surprisingly, also a subset of TP53mutated B-CLL patients might benefit from therapeutic combinations including small molecule activator of the p53 pathway.

}, keywords = {Aged, Aged, 80 and over, Ataxia Telangiectasia Mutated Proteins, Base Sequence, Female, Genes, p53, Humans, Leukemia, Lymphocytic, Chronic, B-Cell, Male, Models, Molecular, Molecular Sequence Data, Mutation, Receptor, Notch1, Signal Transduction, Tumor Suppressor Protein p53}, issn = {1949-2553}, doi = {10.18632/oncotarget.2211}, author = {Athanasakis, Emmanouil and Melloni, Elisabetta and Rigolin, Gian Matteo and Agnoletto, Chiara and Voltan, Rebecca and Vozzi, Diego and Piscianz, Elisa and Segat, Ludovica and dal Monego, Simeone and Cuneo, Antonio and Secchiero, Paola and Zauli, Giorgio} } @article {3581, title = {Sodium dichloroacetate exhibits anti-leukemic activity in B-chronic lymphocytic leukemia (B-CLL) and synergizes with the p53 activator Nutlin-3.}, journal = {Oncotarget}, volume = {5}, year = {2014}, month = {2014 Jun 30}, pages = {4347-60}, abstract = {

The anti-leukemic activity of the mitochondria-targeting small molecule sodium dichloroacetate (DCA), used alone and in association with the small molecule inhibitor of the p53/MDM2 interaction Nutlin-3, was analyzed in primary B-chronic lymphocytic leukemia (B-CLL) samples (n=22), normal peripheral blood cells (n=10) and in p53wild-type EHEB, JVM-2, JVM-3 B lymphoblastoid cell lines. DCA exhibited a dose-dependent anti-leukemic activity in both primary B-CLL and B leukemic cell lines with a functional p53 status and showed a synergistic cytotoxic activity when used in combination with Nutlin-3. At the molecular level, DCA positively regulated p53 activity, as documented by post-transcriptional modifications of p53 protein and synergized with Nutlin-3 in increasing the expression of the p53-target genes MDM2, PUMA, TIGAR and in particular p21. The potential role of p21 in mediating the DCA+Nutlin-3 anti-leukemic activity was underscored in knocking-down experiments. Indeed, transfection of leukemic cells with p21 siRNAs significantly decreased the DCA+Nutlin-3-induced cytotoxicity. Taken together, our data emphasize that DCA is a molecule that merits to be further evaluated as a chemotherapeutic agent for B-CLL, likely in combination with other therapeutic compounds.

}, keywords = {Aged, Aged, 80 and over, Dichloroacetic Acid, Drug Synergism, Female, Humans, Imidazoles, Leukemia, Lymphocytic, Chronic, B-Cell, Male, Middle Aged, Piperazines, Tumor Suppressor Protein p53}, issn = {1949-2553}, author = {Agnoletto, Chiara and Melloni, Elisabetta and Casciano, Fabio and Rigolin, Gian Matteo and Rimondi, Erika and Celeghini, Claudio and Brunelli, Laura and Cuneo, Antonio and Secchiero, Paola and Zauli, Giorgio} } @article {1892, title = {MCL1 down-regulation plays a critical role in mediating the higher anti-leukaemic activity of the multi-kinase inhibitor Sorafenib with respect to Dasatinib.}, journal = {Br J Haematol}, volume = {157}, year = {2012}, month = {2012 May}, pages = {510-4}, keywords = {Antineoplastic Agents, Benzenesulfonates, Cell Line, Tumor, Down-Regulation, Humans, Leukemia, Myeloid, Acute, Myeloid Cell Leukemia Sequence 1 Protein, Niacinamide, Phenylurea Compounds, Protein Kinase Inhibitors, Proto-Oncogene Proteins c-bcl-2, Pyridines, Pyrimidines, Thiazoles}, issn = {1365-2141}, doi = {10.1111/j.1365-2141.2012.09042.x}, author = {Secchiero, Paola and Melloni, Elisabetta and Voltan, Rebecca and Norcio, Alessia and Celeghini, Claudio and Zauli, Giorgio} } @article {1975, title = {Merkel-cell polyomavirus (MCPyV) is rarely associated to B-chronic lymphocytic leukemia (1 out of 50) samples and occurs late in the natural history of the disease.}, journal = {J Clin Virol}, volume = {55}, year = {2012}, month = {2012 Dec}, pages = {367-9}, abstract = {

BACKGROUND: Previous studies have reported conflicting results on the frequency and potential pathogenetic role of Merkel-cell polyomavirus (MCPyV) in B-chronic lymphocytic leukemia (B-CLL).

OBJECTIVES: To evaluate the association of MCPyV to B-CLL and to investigate the occurrence of MCPyV infection in relationship to the natural history of B-CLL.

STUDY DESIGN: Samples of primary B-CLL peripheral blood mononuclear cells were obtained from two distinct University Hospitals of Italy from January 2010. For one B-CLL patient, it was possible to retrospectively examine the blood sample at diagnosis of B-CLL (March 2004) and several pathological tissues of cutaneous tumors occurring during the course of the disease.

RESULTS: Only one out of 50 B-CLL blood samples examined was positive for MCPyV DNA. Retrospective analysis revealed that MCPyV DNA was absent in peripheral blood sample at diagnosis, becoming present only in advanced disease stages also in tonsil tissue as well as in a biopsy of differentiated squamous cell carcinoma.

CONCLUSIONS: The association with MCPyV seems to represent a rare and late event during the natural history of B-CLL.

}, keywords = {Aged, Aged, 80 and over, Blood, Female, Humans, Italy, Leukemia, Lymphocytic, Chronic, B-Cell, Male, Merkel cell polyomavirus, Middle Aged, Palatine Tonsil, Polyomavirus Infections, Prevalence, Skin, Tumor Virus Infections}, issn = {1873-5967}, doi = {10.1016/j.jcv.2012.08.011}, author = {Comar, Manola and Cuneo, Antonio and Maestri, Iva and Melloni, Elisabetta and Pozzato, Gabriele and Soffritti, Olga and Secchiero, Paola and Zauli, Giorgio} } @article {1633, title = {The negative prognostic value of TRAIL overexpression in oral squamous cell carcinomas does not preclude the potential therapeutic use of recombinant TRAIL.}, journal = {Invest New Drugs}, volume = {30}, year = {2012}, month = {2012 Apr}, pages = {810-8}, keywords = {Adult, Aged, Aged, 80 and over, Antineoplastic Agents, Apoptosis, Carcinoma, Squamous Cell, Female, Flow Cytometry, HL-60 Cells, Humans, Immunohistochemistry, Male, Middle Aged, Mouth Neoplasms, Predictive Value of Tests, Prognosis, Proportional Hazards Models, Recombinant Proteins, Risk Assessment, Risk Factors, Survival Analysis, TNF-Related Apoptosis-Inducing Ligand, Tumor Markers, Biological, Up-Regulation, Young Adult}, issn = {1573-0646}, doi = {10.1007/s10637-010-9586-0}, author = {Carinci, Francesco and Monasta, Lorenzo and Rubini, Corrado and Stramazzotti, Daniela and Palmieri, Annalisa and Melloni, Elisabetta and Knowles, Alex and Ronfani, Luca and Zauli, Giorgio and Secchiero, Paola} } @article {1903, title = {SOCS1 is significantly up-regulated in Nutlin-3-treated p53wild-type B chronic lymphocytic leukemia (B-CLL) samples and shows an inverse correlation with miR-155.}, journal = {Invest New Drugs}, volume = {30}, year = {2012}, month = {2012 Dec}, pages = {2403-6}, abstract = {

The basal SOCS1 mRNA levels were significantly lower in p53(mutated) BJAB and MAVER leukemic cell lines with respect to p53(wild-type) SKW6.4 and JVM-2 leukemic cell lines, p53(wild-type) primary B chronic lymphocytic leukemia (B-CLL) cells and primary normal peripheral blood mononuclear cells (PBMC). Moreover, the MDM2 small molecule inhibitor Nutlin-3 significantly increased the levels of SOCS1 mRNA in both primary p53(wild-type) B-CLL cells as well as in p53(wild-type) B leukemic cell lines, but not in p53(mutated) B leukemic cell lines nor in primary PBMC. Of note, a significant inverse correlation was observed between SOCS1 mRNA and miR-155 levels in Nutlin-3-treated primary B-CLL cells and PBMC, suggesting that the miRNA-155/SOCS1 axis represents a potentially important therapeutic target of Nutlin-3 in B-CLL.

}, keywords = {Cell Line, Tumor, Cells, Cultured, Down-Regulation, Humans, Imidazoles, Leukemia, Lymphocytic, Chronic, B-Cell, Leukocytes, Mononuclear, MicroRNAs, Piperazines, Suppressor of Cytokine Signaling Proteins, Tumor Suppressor Protein p53, Up-Regulation}, issn = {1573-0646}, doi = {10.1007/s10637-011-9786-2}, author = {di Iasio, Maria Grazia and Norcio, Alessia and Melloni, Elisabetta and Zauli, Giorgio} } @article {1926, title = {The sorafenib plus nutlin-3 combination promotes synergistic cytotoxicity in acute myeloid leukemic cells irrespectively of FLT3 and p53 status.}, journal = {Haematologica}, volume = {97}, year = {2012}, month = {2012 Nov}, pages = {1722-30}, abstract = {

BACKGROUND: Both the multi-kinase inhibitor sorafenib and the small molecule inhibitor of the MDM2/p53 interaction, nutlin-3, used alone, have shown promising anti-leukemic activity in acute myeloid leukemia cells. Thus, in this study we investigated the effect of the combination of sorafenib plus nutlin-3 in acute myeloid leukemia.

DESIGN AND METHODS: Primary acute myeloid leukemia blasts (n=13) and FLT3(wild-type)/p53(wild-type) (OCI-AML3), FLT3(mutated)/p53(wild-type) (MOLM), FLT3(mutated)/p53(mutated) (MV4-11), FLT3(wild-type)/p53(deleted) (HL60) or FLT3(wild-type)/p53(mutated) (NB4) acute myeloid cell lines were exposed to sorafenib, used alone or in association with nutlin-3 at a 1:1 ratio, in a range of clinically achievable concentrations (1-10 μM). Induction of apoptosis and autophagy was evaluated by transmission electron microscopy and by specific flow cytometry analyses. The levels of Mcl-1, p53 and Bak proteins were analyzed by western blotting. Knock-down of Bax and Bak gene expression was performed in transfection experiments with specific short interfering RNA.

RESULTS: The sorafenib+nutlin-3 drug combination exhibits synergistic cytotoxicity in primary acute myeloid leukemia blasts and in acute myeloid leukemia cell lines with maximal cytotoxicity in FLT3(mutated) MV4-11 and MOLM, followed by the FLT3(wild-type) OCI-AML3, HL60 and NB4 cell lines. The cytotoxic activity of sorafenib+nutlin-3 was characterized by an increase of both apoptosis and autophagy. Moreover, Bax and Bak showed prominent roles in mediating the decrease of cell viability in response to the drug combination in p53(wild-type) OCI-AML3 and p53(deleted) HL-60 cells, respectively, as demonstrated in transfection experiments performed with specific short interfering RNA.

CONCLUSIONS: Our data demonstrate that acute myeloid leukemia cells show a variable but overall good susceptibility to the innovative therapeutic combination of sorafenib+nutlin-3, which differentially involves the pro-apoptotic Bcl-2 family members Bax and Bak in p53(wild-type) and p53(deleted) cells.

}, keywords = {Antineoplastic Agents, Drug Synergism, Female, fms-Like Tyrosine Kinase 3, HL-60 Cells, Humans, Imidazoles, Leukemia, Myeloid, Acute, Male, Niacinamide, Phenylurea Compounds, Piperazines, Tumor Suppressor Protein p53}, issn = {1592-8721}, doi = {10.3324/haematol.2012.062083}, author = {Zauli, Giorgio and Celeghini, Claudio and Melloni, Elisabetta and Voltan, Rebecca and Ongari, Manuele and Tiribelli, Mario and di Iasio, Maria Grazia and Lanza, Francesco and Secchiero, Paola} } @article {1739, title = {Dasatinib plus Nutlin-3 shows synergistic antileukemic activity in both p53 wild-type and p53 mutated B chronic lymphocytic leukemias by inhibiting the Akt pathway.}, journal = {Clin Cancer Res}, volume = {17}, year = {2011}, month = {2011 Feb 15}, pages = {762-70}, abstract = {

PURPOSE: To analyze the effect of the combination of Dasatinib, a multikinase inhibitor, plus Nutlin-3, a nongenotoxic activator of the p53 pathway, in primary B chronic lymphocytic leukemia (B-CLL) patient samples and B leukemic cell line models.

EXPERIMENTAL DESIGN: The induction of cytotoxicity was evaluated in both primary B-CLL cell samples (n = 20) and in p53(wild-type) (EHEB, JVM-2) and p53(deleted/mutated) (MEC-2, BJAB) B leukemic cell lines. The role of Akt in modulating leukemic cell survival/apoptosis in response to Dasatinib or Dasatinib + Nutlin-3 was documented by functional experiments carried out using specific pharmacological inhibitors and by overexpression of membrane-targeted constitutively active form of Akt.

RESULTS: The combination of Dasatinib + Nutlin-3 exhibited a synergistic cytotoxicity in the majority (19 out of 20) of B-CLL samples, including patients carrying 17p- (n = 4), and in both p53(wild-type) and p53(deleted/mutated) B leukemic cell lines. At the molecular level, Dasatinib significantly counteracted the Nutlin-3-mediated induction of the p53 transcriptional targets MDM2 and p21 observed in p53(wild-type) leukemic cells. Conversely, Nutlin-3 did not interfere with the ability of Dasatinib to decrease the phosphorylation levels of ERK1/2, p38/MAPK, and Akt in both p53(wild-type) and p53(deleted/mutated) B leukemic cell lines. A critical role of Akt downregulation in mediating the antileukemic activity of Dasatinib and Dasatinib + Nutlin-3 was demonstrated in experiments carried out by specifically modulating the Akt pathway.

CONCLUSIONS: These findings suggest that Dasatinib + Nutlin-3 might represent an innovative therapeutic combination for both p53(wild-type) and p53(deleted/mutated) B-CLL.

}, keywords = {Antineoplastic Agents, Apoptosis, Cell Line, Tumor, Cell Survival, Down-Regulation, Drug Synergism, Humans, Imidazoles, Leukemia, Lymphocytic, Chronic, B-Cell, Mutation, Piperazines, Protein Kinase Inhibitors, Protein Kinases, Proto-Oncogene Proteins c-akt, Pyrimidines, Thiazoles, Transcription, Genetic, Tumor Suppressor Protein p53}, issn = {1078-0432}, doi = {10.1158/1078-0432.CCR-10-2572}, author = {Zauli, Giorgio and Voltan, Rebecca and Bosco, Raffaella and Melloni, Elisabetta and Marmiroli, Sandra and Rigolin, Gian Matteo and Cuneo, Antonio and Secchiero, Paola} } @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} }