scholarly journals Synergistic suppression of t(8;21)-positive leukemia cell growth by combining oridonin and MAPK1/ERK2 inhibitors

Oncotarget ◽  
2017 ◽  
Vol 8 (34) ◽  
pp. 56991-57002 ◽  
Author(s):  
Pavel Spirin ◽  
Timofey Lebedev ◽  
Natalia Orlova ◽  
Alexey Morozov ◽  
Nadezhda Poymenova ◽  
...  
Keyword(s):  
Cell Growth ◽  
Leukemia Cell

scholarly journals In Vivo RNA Interference Screening Identifies a Leukemia-Specific Dependence on Integrin Beta 3 Signaling

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 758-758
Author(s):  
◽  
Fatima Al-Shahrour ◽  
Kimberly A. Hartwell ◽  
Lisa P Chu ◽  
Jaras Marcus ◽  
...  
Keyword(s):  
Rna Interference ◽  
Cell Growth ◽  
Leukemia Cell ◽  
Leukemia Cells ◽  
Growth And Survival ◽  
Integrin Beta 3 ◽  
Shrna Screen ◽  
Primary Leukemia

Abstract Abstract 758 Primary leukemia stem cells (LSCs) reside in an in vivo microenvironment that supports the growth and survival of malignant cells. Despite the increasing understanding of the importance of niche interactions and primary cell biology in leukemia, many studies continue to focus on cell autonomous processes in artificial model systems. The majority of strategies to-date that attempt to define therapeutic targets in leukemia have relied on screening cell lines in culture; new strategies should incorporate the use of primary disease within a physiologic niche. Using a primary murine MLL-AF9 acute myeloid leukemia (AML) model highly enriched for LSCs, we performed an in vivo short hairpin RNA (shRNA) screen to identify novel genes that are essential for leukemia growth and survival. LSCs infected with pools of shRNA lentivirus were transplanted and grown in recipient mice for 2 weeks, after which bone marrow and spleen cells were isolated. Massively parallel sequencing of infected LSCs isolated before and after transplant was used to quantify the changes in shRNA representation over time. Our in vivo screens were highly sensitive, robust, and reproducible and identified a number of positive controls including genes required for MLL-AF9 transformation (Ctnnb1, Mef2c, Ccna1), genes universally required for cell survival (Ube2j2, Utp18), and genes required in other AML models (Myb, Pbx1, Hmgb3). In our primary and validation screens, multiple shRNAs targeting Integrin Beta 3 (Itgb3) were consistently depleted by more than 20-fold over two weeks in vivo. Follow up studies using RNA interference (RNAi) and Itgb3−/− mice identified Itgb3 as essential for murine leukemia cells growth and transformation in vivo, and loss of Itgb3 conferred a statistically significant survival advantage to recipient mice. Importantly, neither Itgb3 knockdown or genetic loss impaired normal hematopoietic stem and progenitor cell (HSPC) function in 16 week multilineage reconstitution assays. We further identified Itgav as the heterodimeric partner of Itgb3 in our model, and found that knockdown of Itgav inhibited leukemia cell growth in vivo. Consistent the therapeutic aims or our study, flow cytometry on primary human AML samples revealed ITGAV/ITGB3 heterodimer expression. To functionally assess the importance of gene expression in a human system, we performed another RNAi screen on M9 leukemia cells, primary human cord blood CD34+ cells transduced with MLL-ENL that are capable of growing in vitro or in a xenotransplant model in vivo. We found that ITGB3 loss inhibited M9 cell growth in vivo, but not in vitro, consistent with the importance of ITGB3 in a physiologic microenvironment. We explored the signaling pathways downstream of Itgb3 using an additional in vivo, unbiased shRNA screen and identified Syk as a critical mediator of Itgb3 activity in leukemia. Syk knockdown by RNAi inhibited leukemia cell growth in vivo; downregulation of Itgb3 expression resulted in decreased levels of Syk phosphorylation; and expression of an activated form of Syk, TEL-SYK, rescued the effects of Itgb3 knockdown on leukemia cell growth in vivo. To understand cellular processes controlled by Itgb3, we performed gene expression studies and found that, in leukemia cells, Itgb3 knockdown induced differentiation and inhibited multiple previously published LSC transcriptional programs. We confirmed these results using primary leukemia cell histology and a model system of leukemia differentiation. Finally, addition of a small molecule Syk inhibitor, R406, to primary cells co-cultured with bone marrow stroma caused a dose-dependent decrease in leukemia cell growth. Our results establish the significance of the Itgb3 signaling pathway, including Syk, as a potential therapeutic target in AML, and demonstrate the utility of in vivo RNA interference screens. Disclosures: Armstrong: Epizyme: Consultancy.

MDI 301 suppresses myeloid leukemia cell growth in vitro and in vivo without the toxicity associated with all-trans retinoic acid therapy

2015 ◽  
Vol 26 (7) ◽  
pp. 763-773
Author(s):  
Muhammad N. Aslam ◽  
Shannon McClintock ◽  
Shazli P. Khan ◽  
Patricia Perone ◽  
Ronald Allen ◽  
...  
Keyword(s):  
Retinoic Acid ◽  
Cell Growth ◽  
Myeloid Leukemia ◽  
Leukemia Cell ◽  
Acid Therapy ◽  
Trans Retinoic Acid ◽  
All Trans Retinoic Acid ◽  
Myeloid Leukemia Cell

scholarly journals 1,3,4-oxadiazole/chalcone hybrids: Design, synthesis, and inhibition of leukemia cell growth and EGFR, Src, IL-6 and STAT3 activities

2019 ◽  
Vol 84 ◽  
pp. 150-163 ◽  
Author(s):  
Marwa Ali A. Fathi ◽  
Amer Ali Abd El-Hafeez ◽  
Dalia Abdelhamid ◽  
Samar H. Abbas ◽  
Monica M. Montano ◽  
...  
Keyword(s):  
Cell Growth ◽  
Leukemia Cell ◽  
Design Synthesis

Per2 Inhibits K562 Leukemia Cell Growth In Vitro and In Vivo Through Cell Cycle Arrest and Apoptosis Induction

2009 ◽  
Vol 16 (3) ◽  
pp. 403-411 ◽  
Author(s):  
Cheng-ming Sun ◽  
Shi-feng Huang ◽  
Jian-ming Zeng ◽  
Din-bing Liu ◽  
Qing Xiao ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Growth ◽  
Cell Cycle Arrest ◽  
Leukemia Cell ◽  
Apoptosis Induction ◽  
Cycle Arrest

The Jak2V617F Oncogene Associated with Polycythemia Vera Regulates G1/S-Phase Transition.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 3510-3510
Author(s):  
Martin Sattler ◽  
Christoph Walz ◽  
Brian J. Crowley ◽  
Jessica L. Gramlich ◽  
Kendra L. King ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Growth ◽  
Polycythemia Vera ◽  
Cell Cycle Progression ◽  
Kinase Inhibitor ◽  
Active Form ◽  
Leukemia Cell ◽  
Leukemia Cell Line ◽  
Dependent Manner ◽  
Hel Cells

Abstract The V617F activating point mutation in Jak2 has recently been detected in a high proportion of patients with the myeloproliferative disorders polycythemia vera, essential thrombocythemia, and idiopathic myelofibrosis. Using the Jak2V617F-mutant erythroid leukemia cell line HEL as a model, potential mechanisms that contribute to transformation were investigated. Inhibition of Jak2V617F with a small molecule kinase inhibitor reduced cell growth of HEL cells in a dose dependent manner with an IC50 of 300 nM. This inhibition of growth was associated with a G1 cell cycle arrest, with minimal or delayed apoptosis. The major Jak2 target in normal hematopoietic cells, STAT5, was found to be activated by Jak2V617F. Treatment of the cells with either a Jak2 kinase inhibitor, or with a Jak2-targeted siRNA, decreased STAT5 activation, and also resulted in decreased expression of cyclin D2 and increased expression of p27Kip. Of interest, we found that Jak2V617F induced high levels of reactive oxygen species (ROS), an activity associated with several other tyrosine kinase oncogenes. Expression of a constitutively active form of STAT5 by itself was capable reducing expression of p27Kip and increasing production of ROS, suggesting that each of these signaling events are downstream of STAT5. Additionally, treatment of HEL cells with the anti-oxidant N-acetylcystein increased expression of p27Kip, suggesting that Jak2V617F regulates cell cycle progression at least in part through STAT5 activation of ROS, and ROS regulation of p27Kip. Cell growth of HEL cells was found to be blocked by anti-oxidants. Overall, our results suggest that constitutive activation of Jak2 contributes to a transforming phenotype and therefore hints at novel targets for drug development that may aid traditional therapy.

Phenolhexyl Isothiocyanate, a New Histone Deacetylase Inhibitor, Can Prevent Tumor Formation and Inhibit Leukemia Cell Growth In Vivo.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 4625-4625
Author(s):  
Lulu Lu ◽  
Xudong Ma ◽  
A. Becklemisheva ◽  
J.W. Chaio ◽  
Delong Liu
Keyword(s):  
Cell Growth ◽  
Apoptotic Cell ◽  
Leukemia Cell ◽  
Chemotherapeutic Agents ◽  
Tumor Formation ◽  
Control Group ◽  
Immunodeficient Mice ◽  
Standard Design ◽  
Significant Difference

Abstract We have demonstrated that phenolhexyl isothiocyanate (PHI) induces growth arrest and apoptosis in leukemia cells HL-60 through inhibition of the activity of histone deacetylases (HDAC), the enhancement of histone acetylation and activation of p21. In this study, we examined the effects of PHI on the growth of HL-60 leukemic xenograft in immunodeficient mice. The PHI was given to the mice by gavage. The maximum tolerated dose by the mice was determined following standard design. To determine the in vivo effect of PHI on leukemia growth, a sub-MTD dose was given to the control and the treatment groups with 17 mice in each group after injection of 1.0 x 10e6 HL-60 cells per mouse. There was a significant reduction in the incidence of tumor formation (94.1% control group vs 58.5% PHI group, p=0.004). In addition, there was also a significant difference in the tumor size between the two groups. Determined at autopsy, the mean weight of control tumors was 0.8 g vs. the tumors of the experimental group 0.35g, revealing a significant reduction of 44.4% (P<0.03). There were no detectable toxicity as evaluated by body and organ weight, and necropsy examination. The histology of the tumor showed increased apoptotic cell death. Apoptosis in the tumors was further confirmed by the cleavage of poly ADP-ribose polymerase (PARP), the target of proteolysis of caspases that execute apoptosis with Western blot analyses. The results suggest that PHI can prevent tumor formation and inhibit leukemia cell growth in vivo without significant toxicity that is routinely associated with conventional chemotherapeutic agents.

CBX8, a Polycomb-Group Protein, Is Essential for MLL-AF9-Induced Leukemogenesis

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 4174-4174
Author(s):  
Jiaying Tan ◽  
Jay L. Hess
Keyword(s):  
Gene Expression ◽  
Cell Growth ◽  
Cell Lines ◽  
Transcriptional Activation ◽  
Fusion Proteins ◽  
Conflicts Of Interest ◽  
Leukemia Cell ◽  
Polycomb Group ◽  
Human Leukemia ◽  
Interaction Sites

Abstract Abstract 4174 Trithorax and Polycomb-group (Trx-G and Pc-G) proteins are antagonistic regulators of homeobox-containing (Hox) gene expression that play a major role in regulation of hematopoiesis and leukemogenesis. Mixed lineage leukemia (MLL), a mammalian Trx-G protein, is a histone methyltransferase crucial for embryonic development and hematopoiesis that is commonly altered by translocation in acute leukemia. Recent evidence suggests that transformation by MLL fusion proteins is dependent on multiple interaction complexes, including the polymerase associated factor complex (PAFc) and the elongation activating protein complex (EAPc) or a closely related AF4 family/ENL family/P-TEFb complex (AEPc). CBX8 is a human PcG protein, functioning as a transcription repressor in the polycomb repressive complex 1 (PRC1). Previous studies have shown that CBX8 also interacts with the EAPc components AF9 and ENL; however, its role in leukemogenesis is unknown. To elucidate the significance of this interaction between these two proteins thought to have antagonistic function, we generated a large series of point mutations in AF9 and identified two amino acids that are essential for CBX8 interaction but preserve the interaction with other EAP components. Mutation of the two sites reduced the transcriptional activation of the MLL-AF9 target promoters by nearly 50% and completely inhibits the ability of MLL-AF9 to immortalize bone marrow (BM) as assessed by methylcellulose replating assays. This finding suggests that CBX8 interaction is essential for MLL-AF9-induced leukemogenesis. Several lines of evidence further support this finding. First, CBX8 knockdown by siRNAs decreased MLL-AF9-induced transcriptional activation by approximately 50%. Second, the ability of MLL-AF9 to transform primary BM was markedly reduced by retroviral shCbx8 transduction. Notably, this inhibitory effect is specific for MLL-AF9 because the BM transformation ability of E2A-HLF was unaffected by Cbx8 suppression. Third, Cbx8 suppression by shCbx8 in MLL-AF9 and MLL-ENL, but not E2A-HLF transformed AML cell lines, significantly inhibited the expression of MLL-dependent target genes, as well as cell growth and colony forming ability. Fourth, inducing CBX8 knockdown in human leukemia cell lines expressing MLL-AF9 led to a marked decrease in the localization of basic transcription machinery at the Hoxa9 locus and a corresponding reduction in Hoxa9 transcription. Importantly, the observed effects of CBX8 on MLL-rearranged leukemia cells are PRC1-independent: no effects on MLL target gene expression, cell growth, or BM transformation ability were observed by suppressing other core components of PRC1. Taken together, our results indicate that CBX8, independent of its transcription repression role in PRC1, interacts with and synergizes with MLL fusion proteins to promote leukemogenesis. Defining the interaction sites between AF9/ENL and CBX8 and the dependence of other AML subtypes and normal hematopoiesis on CBX8 will be important for the further development of agents that target this mechanism in MLL-rearranged and potentially other AML subtypes. Disclosures: No relevant conflicts of interest to declare.

Sign in / Sign up

Export Citation Format

Share Document