scholarly journals EVI1 oncoprotein expression and CtBP1-association oscillate through the cell cycle

2020 ◽  
Vol 47 (10) ◽  
pp. 8293-8300
Author(s):  
Roberto Paredes ◽  
Marion Schneider ◽  
Stella Pearson ◽  
Hsiang Yin Teng ◽  
James R. Kelly ◽  
...  

Abstract Aberrantly high expression of EVI1 in acute myeloid leukaemia (AML) is associated with poor prognosis. For targeted treatment of EVI1 overexpressing AML a more detailed understanding of aspects of spatiotemporal interaction dynamics of the EVI1 protein is important. EVI1 overexpressing SB1690CB AML cells were used for quantification and protein interaction studies of EVI1 and ΔEVI1. Cells were cell cycle-synchronised by mimosine and nocodazole treatment and expression of EVI1 and related proteins assessed by western blot, immunoprecipitation and immunofluorescence. EVI1 protein levels oscillate through the cell cycle, and EVI1 is degraded partly by the proteasome complex. Both EVI1 and ΔEVI1 interact with the co-repressor CtBP1 but dissociate from CtBP1 complexes during mitosis. Furthermore, a large fraction of EVI1, but not ΔEVI1 or CtBP1, resides in the nuclear matrix. In conclusion, EVI1- protein levels and EVI1-CtBP1 interaction dynamics vary though the cell cycle and differ between EVI1 and ΔEVI1. These data ad to the functional characterisation of the EVI1 protein in AML and will be important for the development of targeted therapeutic approaches for EVI1-driven AML.

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 50-50
Author(s):  
Kana Nakatani ◽  
Hidemasa Matsuo ◽  
Yutarou Harata ◽  
Moe Higashitani ◽  
Asami Koyama ◽  
...  

Acute myeloid leukemia (AML) is a genetically and clinically heterogeneous disease. Although t(8;21) AML patients have a more favorable prognosis than other cytogenetic subgroups, nearly 40% of t(8;21) AML patients experience relapse. Therefore, novel therapeutic approaches based on a better understanding of the biology of t(8;21) AML need to be developed. In this study, at first, we re-analyzed the sequencing data of 149 pediatric t(8;21) AML patients from St. Jude Children's Research Hospital tissue resource core facility and the JPLSG AML-05 study, and 134 adult t(8;21) AML patients from CALGB/Alliance trials and the University Hospital of Ulm. In pediatric patients, 13 CCND2 mutations were detected in 11 patients (11/149, 7.4%), and in adult patients, 14 CCND2 mutations were detected in 12 patients (12/134, 9.0%). In both cohorts, CCND2 mutations were located on the PEST domain, suggesting that the mutations stabilize the cyclin D2 protein. Next, we compared CCND2 mRNA expression between t(8;21) AML patients (n=24) and non-t(8;21) AML patients (n=163) using the TARGET AML cohort. In non-t(8;21) AML patients, CCND2 expression varied from low to high levels, whereas in t(8;21) AML patients, CCND2 expression was restricted to higher levels. Consistently, CCND2 expression was higher in t(8;21) AML cell lines (n=2: Kasumi-1 and SKNO-1), compared with non-t(8;21) AML cell lines (n=32). Kasumi-1 cells transfected with shCCND2 showed cell cycle arrest at G1 phase and impaired cell proliferation. These results suggest that the frequency of CCND2 mutations and CCND2 expression are increased in t(8;21) AML, and high CCND2 expression plays an important role in t(8;21) AML cell proliferation. Because CCND2 is not a druggable target, we examined the effect of CDK4/6 inhibitors (palbociclib and abemaciclib) on t(8;21) AML cells. Analysis of 19 AML cell lines showed that t(8;21) AML cells had lower IC50 values for CDK4/6 inhibitors than non-t(8;21) AML cells. CDK4/6 inhibitors caused cell cycle arrest at G1 phase and impaired cell proliferation in t(8;21) AML cells. To identify potential therapeutic approaches in combination with CDK4/6 inhibitors in t(8;21) AML, we performed microarray analysis and examined the effects of CDK4/6 inhibition. In addition to the pathways associated with the cell cycle (regulation of sister chromatid separation, retinoblastoma gene, and cell cycle), the MAP-ERK and PI3K-AKT-mTOR signaling pathways were downregulated by CDK4/6 inhibition. Because these pathways are involved in autophagy regulation via mTOR, we focused on examining autophagy in subsequent experiments. Assessment of the effect of CDK4/6 inhibition on autophagy in t(8;21) AML cells showed that the CDK4/6 inhibitor (abemaciclib) treatment induced LC3B-I to LC3B-II conversion in both Kasumi-1 and SKNO-1 cells. Transmission electron microscopic examination of autophagosome formation detected a large number of autophagosomes in the cytoplasm of Kasumi-1 and SKNO-1 cells treated with abemaciclib, whereas few autophagosomes were detected in control samples. These results suggest that autophagy is induced by CDK4/6 inhibition in t(8;21) AML cells. Autophagy is involved in the resistance to chemotherapy in cancer cells, therefore, we hypothesized that autophagy inhibition may be a promising therapeutic approach. Treatment of t(8;21) AML cells with the autophagy inhibitors chloroquine (CQ) or LY294002 in combination with abemaciclib significantly increased the frequency of apoptotic (Annexin V positive) cells compared with that in untreated cells, whereas CQ or LY294002 single treatment had no significant effect on apoptosis. Consistently, combinatorial inhibition of CDK4/6 and autophagy upregulated cleaved caspase 3 expression. The combinatorial effect was confirmed by silencing the autophagy-related protein ATG7 using small interfering RNA in abemaciclib-treated t(8;21) AML cells. These results suggest that autophagy inhibition enhances CDK4/6 inhibitor-induced apoptosis in t(8;21) AML cells. In conclusion, the present results indicate that inhibition of CDK4/6 and autophagy may be a novel and promising biomarker-driven therapeutic strategy for the treatment of t(8;21) AML. Disclosures: No relevant conflicts of interest to declare.


2017 ◽  
Vol Volume 10 ◽  
pp. 3635-3644 ◽  
Author(s):  
Hong Guo ◽  
Ting-juan Zhang ◽  
Xiang-mei Wen ◽  
Jing-dong Zhou ◽  
Ji-chun Ma ◽  
...  

Author(s):  
Amit Verma ◽  
Swetha Gunasekar ◽  
Vineeta Goel ◽  
Randeep Singh ◽  
Ramandeep Singh Arora ◽  
...  

<p>Glioma is a tumor of the central nervous system that occurs in the glial cells, Which it surrounds and protects the nerve cells. Glioblastoma Multiforme (GBM) is the most common and malignant sub-type of gliomas that arises from star-shaped cells called “astrocytes”, which constitute the supportive tissue of the brain. GBM are known to be heterogeneous in outcome with majority having a poor prognosis, thus there is an urgent need for novel therapeutic approaches. The detailed understanding of GBM is established by the combination of histopathology and genomic information of the tumor that aids in the best choice of Personalized Medicine. In this article, seven GBM patients are discussed who underwent tissue diagnosis as well as tumor molecular profiling; the significance of the genes and associated mutations/variations picked up in each individual.</p>


2021 ◽  
Vol 17 (3) ◽  
pp. e1008805
Author(s):  
David Holcomb ◽  
Aikaterini Alexaki ◽  
Nancy Hernandez ◽  
Ryan Hunt ◽  
Kyle Laurie ◽  
...  

Thrombosis is a recognized complication of Coronavirus disease of 2019 (COVID-19) illness and is often associated with poor prognosis. There is a well-recognized link between coagulation and inflammation, however, the extent of thrombotic events associated with COVID-19 warrants further investigation. Poly(A) Binding Protein Cytoplasmic 4 (PABPC4), Serine/Cysteine Proteinase Inhibitor Clade G Member 1 (SERPING1) and Vitamin K epOxide Reductase Complex subunit 1 (VKORC1), which are all proteins linked to coagulation, have been shown to interact with SARS proteins. We computationally examined the interaction of these with SARS-CoV-2 proteins and, in the case of VKORC1, we describe its binding to ORF7a in detail. We examined the occurrence of variants of each of these proteins across populations and interrogated their potential contribution to COVID-19 severity. Potential mechanisms, by which some of these variants may contribute to disease, are proposed. Some of these variants are prevalent in minority groups that are disproportionally affected by severe COVID-19. Therefore, we are proposing that further investigation around these variants may lead to better understanding of disease pathogenesis in minority groups and more informed therapeutic approaches.


2018 ◽  
Vol 51 (1) ◽  
pp. 1-10 ◽  
Author(s):  
Yuan Qiao ◽  
Jingtao Chen ◽  
Chao Ma ◽  
Yingmin Liu ◽  
Peitong Li ◽  
...  

Background/Aims: Lung cancer is the leading cause of cancer-related deaths worldwide. The outcome of patients with non-small cell lung cancer remains poor; the 5-year survival rate for stage IV non-small cell lung cancer is only 1.0%. KIF15 is a tetrameric kinesin spindle motor that has been investigated for its regulation of mitosis. While the roles of kinesin motor proteins in the regulation of mitosis and their potentials as therapeutic targets in pancreatic cancer have been described previously, the role of KIF15 in lung cancer development remains unknown. Methods: Paired lung carcinoma specimens and matched adjacent normal tissues were used for protein analysis. Clinical data were obtained from medical records. We first examined KIF15 messenger RNA expression in The Cancer Genome Atlas database, and then determined KIF15 protein levels using immunohistochemistry and western blotting. Differences between the groups were analyzed using repeated measures analysis of variance. Overall survival was analyzed using the Kaplan–Meier method. Cell-cycle and proliferation assays were conducted using A549, NCI-H1299, and NCI-H226 cells. Results: KIF15 was significantly upregulated at both the messenger RNA and protein levels in human lung tumor tissues. In patients with lung adenocarcinoma, KIF15 expression was positively associated with disease stages; high KIF15 expression predicted a poor prognosis. KIF15 knockdown using short hairpin RNA in two human lung adenocarcinoma cell lines induced G1/S phase cell cycle arrest and inhibited cell growth, but there was no effect in human lung squamous cell carcinoma. Conclusion: Our findings show that KIF15 is involved in lung cancer carcinogenesis. KIF15 could therefore serve as a specific prognostic marker for patients with lung adenocarcinoma.


Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 3216-3216
Author(s):  
Florencia Palacios ◽  
Xiao J. Yan ◽  
Jacqueline C. Barrientos ◽  
Jonathan E. Kolitz ◽  
Steven L. Allen ◽  
...  

CLL develops from a small fraction of dividing monoclonal CD5+ B cells. The size and rate of growth of this proliferative fraction (PF) correlates inversely with time-to-first-treatment and directly with poor outcome prognostic markers. Furthermore, since the dividing cells upregulate DNA mutators such as AID and APOBEC family members, the PF has a greater propensity for acquiring new DNA abnormalities that can lead to more lethal disease. Hence, cells of the PF are important targets for therapy for patients with worst outcome category. The PF (CXCR4DimCD5Bright) differs by more than 1000 genes from the resting fraction (RF, CXCR4Bright CD5Dim); these genes relate to replication, migration, and regulation of gene expression. Some of these genes are also preferentially expressed in the PF of U-CLL cases. One such gene is Musashi 2 (MSI2). MSI2 regulates gene expression by binding consensus sequences of mRNA and blocking protein translation. High MSI2 expression is involved in proliferation of normal and malignant stem cells, tumorigenesis, and poor outcome. In CLL, high MSI2 mRNA expression has been identified in patients with worse prognosis. Nevertheless, nothing is known about the function of MSI2 in CLL cells. Therefore, we report studies of the biological role of MSI2 in B-CLL cells and its possible association with B-cell proliferation and CLL disease progression. First, we evaluated MSI2 protein levels by flow cytometry in CD19+CD5- and CD19+CD5+ cells from healthy donors (HDs; n=25) and in CD19+CD5+ from CLL patients (n=55). Higher MSI2 expression was observed in CLL than HD B cells, whereas no differences were found in CD19+CD5+ and CD19+CD5- cells from HDs. Also, MSI2 protein levels were higher in U-CLL than M-CLL, and M-CLL B cells express more MSI2 than HDs. Finally, MSI2 protein levels correlated with CD38, a CLL poor prognosis marker, suggesting MSI2 associates with poor prognosis in CLL. Within the leukemic clone, we observed 25% more MSI2 in the PF than the Int (defined as CXCR4intCD5int) and 15% more in the Int than the RF (PF>Int >RF). The PF contains 40% more MSI2 than the RF, suggesting the highest amounts of MSI2 protein are in dividing and recently-divided cells. Since CLL B cell proliferation occurs in the microenvironment of lymphoid organs, presumably delivered by external signals, we tested whether such signals could stimulate MSI2 expression. Results indicate that CD40L+IL4 and Toll-like 9 stimulation plus IL15 (TLR9+IL5) increase MSI2 synthesis in vitro 1.4 and 1.8 fold, respectively. The increases are associated with the appearance of phospho ERK and AKT. Also, inhibition of AKT signaling by a PI3K inhibitor decreases MSI2 levels, suggesting AKT is involved in MSI2 synthesis. In this regard, signals from the microenvironment inducing cell growth and proliferation promote MSI2 synthesis in B cells from CLL patients. In addition, cells entering the cell cycle (Ki-67+ cells, those incorporating the thymidine analogue EdU, and cells in S, G2 and M cell cycle phases) express higher MSI2 levels than quiescent cells. Furthermore, dividing cells contain higher MSI2 levels than non-dividing cells as determined by CFSE dilution. These results suggest that cells entering the cell cycle or recently dividing have greater MSI2 expression. Since high MSI2 levels associate with cell proliferation and its inhibition is said to promote apoptosis, we studied the effect of MSI2 downregulation in the CLL MEC1 cell line to determine if MSI2 is a potential therapeutic target for CLL. Our findings show that siRNAs decrease MSI2 mRNA (80%) and protein (40%) levels compared to negative controls. Downregulation of MSI2 in MEC1 led to cleaved caspase 3, TRAIL R1 and R2, FADD, TNFR1, P21, P27, phosho-p53, and decreased levels of inhibitors of apoptosis such as cIAP2 and survivin. Hence these data suggest downregulation of MSI2 in CLL cells could induce apoptosis. Thus, MSI2 levels are higher in B cells from poor outcome patients and also in the dividing/divided cells of the PF before and after stimulation. Also, MSI's downregulation induces apoptosis of CLL cell line. Therefore, we propose that MSI2 is a valuable target for therapeutic intervention. Inhibiting its function and its role in cell proliferation will likely abort clonal evolution and disease progression, and make CLL an even more chronic and manageable condition. Disclosures No relevant conflicts of interest to declare.


2010 ◽  
Vol 112 (6) ◽  
pp. 1325-1334 ◽  
Author(s):  
Ge Liang ◽  
Christopher Ward ◽  
Jun Peng ◽  
Yifan Zhao ◽  
Baosheng Huang ◽  
...  

Background We hypothesized that isoflurane has a greater potency to induce neurodegeneration than sevoflurane in the developing brains of neonatal mice based on our previous studies in cell culture. Methods We treated 7-day-old mice with either 0.75% isoflurane or 1.1% sevoflurane ( approximately 0.5 minimum alveolar concentration) for 6 h and then obtained blood and brain samples at 2 h after the anesthesia treatment for determination of neuroapoptosis in different brain regions and the neurodegenerative biomarker S100beta in the blood. The mechanisms of neurodegeneration induced by isoflurane or sevoflurane were also compared by determining protein expressions of the cell cycle and apoptosis-related proteins. In separate groups, memory and learning ability were evaluated through the use of Morris Water Maze testing in mice at postnatal day 42 after anesthesia treatment at postnatal day 7. Results Isoflurane but not sevoflurane significantly increased the neurodegenerative biomarker S100beta in the blood. Isoflurane treatments significantly increased apoptosis indicated by the activation of caspase-3 and elevation of poly-(ADP-ribose) polymerase in different brain regions. An equipotent exposure of sevoflurane tended to increase apoptosis in hippocampal and cortex areas but was significantly less potent than isoflurane. Neither isoflurane nor sevoflurane significantly changed protein levels of glyceraldehyde-3-phosphate dehydrogenase, beta-site amyloid beta-precursor protein-cleaving enzyme, and cell cycle regulatory proteins (CDK4, cyclin D1). Isoflurane and sevoflurane at the selected exposures did not significantly alter memory and learning ability. Conclusion At equipotent exposures, isoflurane has a greater potency than sevoflurane to cause neurodegeneration in the developing brains of neonatal mice.


2018 ◽  
Vol Volume 11 ◽  
pp. 689-702 ◽  
Author(s):  
Hanning Ying ◽  
Zhiyao Xu ◽  
Mingming Chen ◽  
Senjun Zhou ◽  
Xiao Liang ◽  
...  

2006 ◽  
Vol 114 (S 1) ◽  
Author(s):  
B Trojanowicz ◽  
Z Chen ◽  
J Bialek ◽  
Y Radestock ◽  
S Hombach-Klonisch ◽  
...  

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