miR-34a contributes to megakaryocytic differentiation of K562 cells independently of p53

Blood ◽  
2009 ◽  
Vol 114 (10) ◽  
pp. 2181-2192 ◽  
Author(s):  
Francisco Navarro ◽  
David Gutman ◽  
Eti Meire ◽  
Mario Cáceres ◽  
Isidore Rigoutsos ◽  
...  
Keyword(s):  
Phorbol Ester ◽  
Target Genes ◽  
Phorbol Esters ◽  
K562 Cells ◽  
Suppressor Gene ◽  
Human Leukemia ◽  
Cycle Arrest ◽  
Human Leukemia Cells ◽  
Megakaryocyte Differentiation

Abstract The role of miRNAs in regulating megakaryocyte differentiation was examined using bipotent K562 human leukemia cells. miR-34a is strongly up-regulated during phorbol ester–induced megakaryocyte differentiation, but not during hemin-induced erythrocyte differentiation. Enforced expression of miR-34a in K562 cells inhibits cell proliferation, induces cell-cycle arrest in G1 phase, and promotes megakaryocyte differentiation as measured by CD41 induction. miR-34a expression is also up-regulated during thrombopoietin-induced differentiation of CD34+ hematopoietic precursors, and its enforced expression in these cells significantly increases the number of megakaryocyte colonies. miR-34a directly regulates expression of MYB, facilitating megakaryocyte differentiation, and of CDK4 and CDK6, to inhibit the G1/S transition. However, these miR-34a target genes are down-regulated rapidly after inducing megakaryocyte differentiation before miR-34a is induced. This suggests that miR-34a is not responsible for the initial down-regulation but may contribute to maintaining their suppression later on. Previous studies have implicated miR-34a as a tumor suppressor gene whose transcription is activated by p53. However, in p53-null K562 cells, phorbol esters induce miR-34a expression independently of p53 by activating an alternative phorbol ester-responsive promoter to produce a longer pri-miR-34a transcript.

scholarly journals Harmine Hydrochloride Induced G2/M Phase Cell Cycle Arrest, Autophagy and Apoptosis in Human Leukemia K562 Cells through Modulation of the MAPK Pathway

2021 ◽  
Author(s):  
Zhilong Liu ◽  
Peng Zhang ◽  
Na Zhao ◽  
Lin-lin Lv ◽  
Ziyu Li ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Caspase 3 ◽  
K562 Cells ◽  
Leukemia Cells ◽  
Phase Cell ◽  
Human Leukemia ◽  
Cycle Arrest ◽  
Human Leukemia Cells ◽  
M Phase ◽  
Human Leukemia K562 Cells

Abstract Background Previous studies have indicated that harmine hydrochloride (HAR-HC) has anti-tumor characteristics. However, its potential impact on human leukemia cells is unknown. In this study, we explored the potential mechanism of HAR-HC effects on human leukemia cells in vitro. Methods MTT assay was used to detect cell viability; A flow cytometer was used to analyze the cell cycle; Anexinn V-FITC/PI was used to detect cell apoptosis; Western blotting assay was used to analyze the expression of related proteins. Results The result of flow cytometry suggested G2/M phage arrest in K562 cells induced by HAR-HC. The expression levels of Cyclin E2, Cyclin D1, Bcl-2, Bcl-xL, Mcl-1, pro-caspase-3, and PARP decreased and the expression levels of Cyclin A2, Cyclin B1, p21, Myt-1, p-cdc2 (Tyr15), cleaved -caspase-3 and cleaved-PARP increased. Moreover, the expression of p-JNK and p-ERK1/2 increased and autophagy was induced in the HAR-HC treatment group. Additionally, HAR-HC facilitated autophagy by activating the ERK1/2 pathway. Conclusion HAR-HC induced G2/M phase cell cycle arrest, autophagy and apoptosis by activating the JNK, and ERK1/2 pathways in the human leukemia K562 cells.

scholarly journals Roles of pRB in the Regulation of Nucleosome and Chromatin Structures

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Chiharu Uchida
Keyword(s):  
Target Genes ◽  
Chromosome Instability ◽  
Cancer Therapies ◽  
Induce Cell Cycle Arrest ◽  
Cellular Events ◽  
Cycle Arrest ◽  
Histone Modifiers ◽  
Physical Interactions ◽  
Functional Inactivation

Retinoblastoma protein (pRB) interacts with E2F and other protein factors to play a pivotal role in regulating the expression of target genes that induce cell cycle arrest, apoptosis, and differentiation. pRB controls the local promoter activity and has the ability to change the structure of nucleosomes and/or chromosomes via histone modification, epigenetic changes, chromatin remodeling, and chromosome organization. Functional inactivation of pRB perturbs these cellular events and causes dysregulated cell growth and chromosome instability, which are hallmarks of cancer cells. The role of pRB in regulation of nucleosome/chromatin structures has been shown to link to tumor suppression. This review focuses on the ability of pRB to control nucleosome/chromatin structures via physical interactions with histone modifiers and chromatin factors and describes cancer therapies based on targeting these protein factors.

scholarly journals From cytopenia to leukemia: the role of Gfi1 and Gfi1b in blood formation

Blood ◽  
2015 ◽  
Vol 126 (24) ◽  
pp. 2561-2569 ◽  
Author(s):  
Tarik Möröy ◽  
Lothar Vassen ◽  
Brian Wilkes ◽  
Cyrus Khandanpour
Keyword(s):  
Zinc Finger ◽  
Target Genes ◽  
Integration Site ◽  
Wide Spectrum ◽  
Human Leukemia ◽  
Specific Expression ◽  
Hematopoietic Stem ◽  
Proviral Integration Site ◽  
Cell Type Specific Expression

AbstractThe DNA-binding zinc finger transcription factors Gfi1 and Gfi1b were discovered more than 20 years ago and are recognized today as major regulators of both early hematopoiesis and hematopoietic stem cells. Both proteins function as transcriptional repressors by recruiting histone-modifying enzymes to promoters and enhancers of target genes. The establishment of Gfi1 and Gfi1b reporter mice made it possible to visualize their cell type–specific expression and to understand their function in hematopoietic lineages. We now know that Gfi1 is primarily important in myeloid and lymphoid differentiation, whereas Gfi1b is crucial for the generation of red blood cells and platelets. Several rare hematologic diseases are associated with acquired or inheritable mutations in the GFI1 and GFI1B genes. Certain patients with severe congenital neutropenia carry mutations in the GFI1 gene that lead to the disruption of the C-terminal zinc finger domains. Other mutations have been found in the GFI1B gene in families with inherited bleeding disorders. In addition, the Gfi1 locus is frequently found to be a proviral integration site in retrovirus-induced lymphomagenesis, and new, emerging data suggest a role of Gfi1 in human leukemia and lymphoma, underlining the role of both factors not only in normal hematopoiesis, but also in a wide spectrum of human blood diseases.

scholarly journals Pterostilbene induces cell cycle arrest and apoptosis in MOLT4 human leukemia cells

2012 ◽  
Vol 50 (4) ◽  
pp. 574-580 ◽  
Author(s):  
Kamila Siedlecka-Kroplewska ◽  
Agnieszka Jozwik ◽  
Lucyna Kaszubowska ◽  
Anna Kowalczyk ◽  
Wojciech Boguslawski
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Arrest ◽  
Leukemia Cells ◽  
Human Leukemia ◽  
Cycle Arrest ◽  
Human Leukemia Cells

scholarly journals The Role of E4BP4 in Apoptosis of Human Leukemia Cells in Culture

2019 ◽  
Vol 33 (S1) ◽  
Author(s):  
Erick Lenin Mitchell‐Velasquez ◽  
Danny Gomez ◽  
Rheem D Medh
Keyword(s):  
Leukemia Cells ◽  
Human Leukemia ◽  
Cells In Culture ◽  
Human Leukemia Cells

scholarly journals The multiple myeloma–associated MMSET gene contributes to cellular adhesion, clonogenic growth, and tumorigenicity

Blood ◽  
2008 ◽  
Vol 111 (2) ◽  
pp. 856-864 ◽  
Author(s):  
Josh Lauring ◽  
Abde M. Abukhdeir ◽  
Hiroyuki Konishi ◽  
Joseph P. Garay ◽  
John P. Gustin ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Poor Prognosis ◽  
Target Genes ◽  
Hematologic Malignancy ◽  
Growth Factor Receptor ◽  
Cellular Adhesion ◽  
Tumor Formation ◽  
Set Domain ◽  
Cycle Arrest

Multiple myeloma (MM) is an incurable hematologic malignancy characterized by recurrent chromosomal translocations. Patients with t(4;14)(p16;q32) are the worst prognostic subgroup in MM, although the basis for this poor prognosis is unknown. The t(4;14) is unusual in that it involves 2 potential target genes: fibroblast growth factor receptor 3 (FGFR3) and multiple myeloma SET domain (MMSET). MMSET is universally overexpressed in t(4;14) MM, whereas FGFR3 expression is lost in one-third of cases. Nonetheless, the role of MMSET in t(4;14) MM has remained unclear. Here we demonstrate a role for MMSET in t(4;14) MM cells. Down-regulation of MMSET expression in MM cell lines by RNA interference and by selective disruption of the translocated MMSET allele using gene targeting dramatically reduced colony formation in methylcellulose but had only modest effects in liquid culture. In addition, MMSET knockdown led to cell-cycle arrest of adherent MM cells and reduced the ability of MM cells to adhere to extracellular matrix. Finally, MMSET knockdown and knockout reduced tumor formation by MM xenografts. These results provide the first direct evidence that MMSET plays a significant role in t(4;14) MM and suggest that therapies targeting this gene could impact this particular subset of poor-prognosis patients.

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