scholarly journals p15INK4b, a Tumor Suppressor in Acute Myeloid Leukemia

Author(s):  
Joanna Fares ◽  
Linda Wolff ◽  
Juraj Bies
2017 ◽  
Vol 53 ◽  
pp. S52
Author(s):  
Jan-Henning Klusmann ◽  
Razan Jammal ◽  
Kathrin Krowiorz ◽  
Nadine Haetscher ◽  
Raj Bhayadia ◽  
...  

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Yunqi Zhu ◽  
Xiangmin Tong ◽  
Ying Wang ◽  
Xiaoya Lu

AbstractAcute myeloid leukemia (AML) is an aggressive and heterogeneous clonal hematologic malignancy for which novel therapeutic targets and strategies are required. Emerging evidence suggests that WTIP is a candidate tumor suppressor. However, the molecular mechanisms of WTIP in leukemogenesis have not been explored. Here, we report that WTIP expression is significantly reduced both in AML cell lines and clinical specimens compared with normal controls, and low levels of WTIP correlate with decreased overall survival in AML patients. Overexpression of WTIP inhibits cell proliferation and induces apoptosis both in vitro and in vivo. Mechanistic studies reveal that the apoptotic function of WTIP is mediated by upregulation and nuclear translocation of FOXO3a, a member of Forkhead box O (FOXO) transcription factors involved in tumor suppression. We further demonstrate that WTIP interacts with FOXO3a and transcriptionally activates FOXO3a. Upon transcriptional activation of FOXO3a, its downstream target PUMA is increased, leading to activation of the intrinsic apoptotic pathway. Collectively, our results suggest that WTIP is a tumor suppressor and a potential target for therapeutic intervention in AML.


PLoS ONE ◽  
2015 ◽  
Vol 10 (5) ◽  
pp. e0125783 ◽  
Author(s):  
Mirle Schemionek ◽  
Behzad Kharabi Masouleh ◽  
Yvonne Klaile ◽  
Utz Krug ◽  
Katja Hebestreit ◽  
...  

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 28-28
Author(s):  
Hassan Awada ◽  
Arda Durmaz ◽  
Carmelo Gurnari ◽  
Misam Zawit ◽  
Sunisa Kongkiatkamon ◽  
...  

Mutations in tumor suppressor genes and oncogenes are both potentially therapeutically actionable in acute myeloid leukemia (AML). The Wilms' Tumor 1 (WT1) gene is located on 11p13 and encodes a zinc finger transcription factor which has been found to be overexpressed and mutated in AML. In normal development, WT1 is only expressed in a small subset of hematopoietic stem cells. While its overexpression suggests an oncogenic role, the invariable presence of mutations in the cysteine-histidine zinc finger domains indicates a tumor suppressor function, similar to that in WAGR syndrome/11p deletion syndrome in which it was first discovered. Like its unknown function in AML, the clinical significance and genetic associations of WT1 mutations have been also controversial. Although studies of WT1 mutations in AML have been conducted, the lack of solid clinical and molecular characterization of large WT1-mutant (WT1MT) AML cohort has hampered its definition. In this study, we took advantage of a compendia of genomic results from Cleveland Clinic and publicly available data of 2188 AML patients (primary (p)AML, n= 1636; secondary (s)AML, n= 433; therapy-related (t)AML, n= 119, excluding cases with acute promyelocytic leukemia, MLL-rearrangement, and core-binding factor AML). While several reports only focused on cytogenetic normal AML (CN-AML), which represented 61% of our cohort, we additionally included all other cytogenetic risk groups. In total, WT1 mutations were detected in 5% (114/2188) of patients. WT1 mutations were enriched in pAML (85%) compared to sAML (11%) and tAML (4%). Thirty-nine patients (13%) carried more than 1 WT1 mutation. WT1MT were younger [59 vs 64 years, P=0.0002] and more often females (55% vs 45%, P=0.03) as compared to WT1 wild type (WT1WT) patients. Univariate analyses of baseline parameters showed that WT1MT AML had a more proliferative phenotype with a higher WBC [15.1 vs 9.5 x109/L, P=0.03] and bone marrow blast percentages [73 vs 59%, P=0.002] and with lower platelet counts [44 vs 56 x109/L, P=0.008] compared to WT1WT cases. In the WT1MT cohort, 70% had a normal karyotype, with complex karyotype being significantly less frequent vsWT1WT patients [4 vs 16%, P=0.001]. The most common cytogenetic abnormalities in WT1MT patients included +8 (8%) followed by -9/del(9q) (3%) and -7/del(7q) (3%). Only 1 patient carried inv(3)/t(3;3) or -17/del(17p). In sum, no statistical differences in cytogenetics were found between WT1MTvsWT1WT AML patients. Next, identified mutational signatures of WT1MT patients. A panel of 44 myeloid genes and their hotspot configurations were selected according to their relevance in AML. In comparison to WT1WT AML patients, multivariate analyses showed that WT1MT patients had higher odds of biallelic CEBPA (12 vs 3%; P=0.009) and FLT3 internal tandem duplication mutations (FLT3ITD, 31 vs 16%; P=0.01) but lower odds of SRSF2 mutations (2 vs 9%, P=0.04). Since FLT3ITD has been previously described to be associated with WT1 mutations, we also focused on investigating whether mutations in the tyrosine kinase domain (TKD) were frequent in WT1MT as well. Although we found increased percentages of FLT3TKD (11%) among the WT1MT patients compared to WT1WT cohort (8%), this difference did not reach statistical significance. To uncover multifactor lesions (cytogenetic and/ or additional molecular lesions) of prognostic importance, we performed survival analyses. Although the combination of WT1 mutations and FLT3TKD shortened overall survival (OS) by 2-times in WT1MT patients vsWT1WT cases with FLT3TKD (23.7 vs 45.9 months), this result was not significant (P=0.1). In addition, the concurrent presence of other cytogenetic and molecular features didn't reveal significant impact on OS. In sum, using an adequately powered cohort, our study of the genomic landscape of WT1MT AML patients identified its genomic associations and their clinical and prognostic inferences. The application of advanced machine learning methods to large datasets of WT1MT AML patients might be crucial to capture the complex genomic interactions of WT1 gene in AML. Disclosures Carraway: BMS: Consultancy, Other: Research support, Speakers Bureau; Stemline: Consultancy, Speakers Bureau; Takeda: Other: Independent Advisory Committe (IRC); ASTEX: Other: Independent Advisory Committe (IRC); Abbvie: Other: Independent Advisory Committe (IRC); Novartis: Consultancy, Speakers Bureau; Jazz: Consultancy, Speakers Bureau. Nazha:MEI: Other: Data monitoring Committee; Novartis: Speakers Bureau; Incyte: Speakers Bureau; Jazz: Research Funding. Sekeres:Pfizer: Consultancy; BMS: Consultancy; Takeda/Millenium: Consultancy. Maciejewski:Alexion, BMS: Speakers Bureau; Novartis, Roche: Consultancy, Honoraria.


Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 365-365
Author(s):  
Hilmar Quentmeier ◽  
Sonja Röhrs ◽  
Wilhelm G Dirks ◽  
Claus Meyer ◽  
Rolf Marschalek ◽  
...  

Abstract Abstract 365 Background: Translocations of the Mixed Lineage Leukemia (MLL) gene occur in a subset (5%) of acute myeloid leukemia (AML) and in mixed phenotype acute leukemia in infancy, a disease with extremely poor prognosis. Animal model systems show that MLL gain of function mutations may contribute to leukemogenesis. Wild-type MLL carries histone methyltransferase activity and affects specific target genes, such us HOXA cluster genes. While the more than three dozen MLL fusion proteins known today exert different specific functions, they finally induce transcription of individual target genes. Consequently, acute lymphoblastic leukemias (ALL) with MLL mutations (MLLmu) exhibit typical gene expression profiles including high-level expression of HOXA cluster genes. Aim of this study was to find a correlation between the MLL mutational status and tumor suppressor gene methylation/expression in acute leukemia cell lines. Results: Using MS-MLPA (methylation-specific multiplex ligation-dependent probe amplification assay), methylation of 24 different TSG was analyzed in 28 MLLmu and MLLwt acute leukemia cell lines. 1.8/24 TSG were methylated in MLLmu AML cells, 6.2/24 TSG were methylated in MLLwt AML cells. Hypomethylation and expression of the tumor suppressor genes (TSG) BEX2, IGSF4 and TIMP3 turned out to be characteristic of MLLmu acute myeloid leukemia (AML) cell lines. MLL wild-type (MLLwt) AML cell lines displayed hypermethylated TSG promoters resulting in transcriptional silencing. Demethylating agents and inhibitors of histone deacetylases restored expression of BEX2, IGSF4 and TIMP3 confirming epigenetic silencing of these genes in MLLwt cells. The positive correlation between MLL translocation, TSG hypomethylation and expression suggested that MLL fusion proteins were responsible for dysregulation of TSG expression in MLLmu cells. This concept was supported by our observation that Bex2 mRNA levels in MLL-ENL transgenic mouse cell lines required expression of the MLL fusion gene. Conclusion: These results suggest that the conspicuous expression of the TSG BEX2, IGSF4 and TIMP3 in MLLmu AML cell lines is the consequence of altered epigenetic properties of MLL fusion proteins. Disclosures: No relevant conflicts of interest to declare.


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