GLI1 Directly Regulates the Transcription of AKT Genes in Diffuse Large B-Cell Lymphoma.

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 2399-2399
Author(s):  
Nitin K Agarwal ◽  
Changju Qu ◽  
Kranthi Kunkalla ◽  
Yadong Liu ◽  
Francisco Vega
Keyword(s):  
Cell Viability ◽  
Cell Survival ◽  
Mrna Expression ◽  
Real Time ◽  
Cell Lines ◽  
Real Time Pcr ◽  
Luciferase Reporter ◽  
Knock Down ◽  
Hh Signaling

Abstract Abstract 2399 Activation of the Hedgehog (Hh)/glioma-associated oncogene (GLI) pathway has been found in a growing number of malignancies. We have provided evidence that canonical Hh signaling is required for cell survival and proliferation of DLBCL cell lines. To confirm the pathogenic role of GLI1 in DLBCL, we established GLI1 knock down DLBCL cell lines (OCI-Ly19, HBL-1 and BJAB) using a lentiviral shRNA system and performed cell viability and apoptosis assays. Cell viability assays demonstrated that GLI1 knockdown DLBCL cells experienced a statistically significantly decrease in the number of viable cells in comparison with control cells harboring scramble shRNA. To examine whether decreases number of cell viability in GLI1 knock down cells were due to apoptosis, we performed annexin V and PI assays. We observed marked increase of apoptosis in GLI1 knock down DLBCL cells versus controls (2.5 fold increase for OCI-Ly10, and 5 fold for HBL1 and BJAB). To investigate the mechanism by which GLI1 regulates tumorigenesis and cell survival, we searched for whole genome GLI1-target genes in DLBCL cells using CHIP sequencing technique and identified AKT genes as potential targets of GLI1. Using pharmacological and silencing approaches, we observed that Hh signaling modulates the expression of AKT genes in DLBCL cells. We further identified two putative binding sites for GLI1 in the AKT1 promoter region and confirmed their functionality using chromatin immunoprecipitation, luciferase reporter and site-directed mutagenesis assays. To investigate whether there is any correlation between AKT1 and GLI1 mRNA expression in human DLBCL tumors, we performed quantitative real-time PCR analyses in 17 frozen DLBCL specimens including apharesis samples from pleural effusions. The real time PCR analysis revealed a strong Spearmen correlation coefficient (R2=0.9) between GLI1 and AKT1 mRNA expression. In summary, we provide evidence of the role of GLI1 in the pathobiology of DLBCL and demonstrated a cross talk, at the transcriptional level, between Hh signaling and AKT in DLBCL. A link between these 2 pathways at the trasncriptional level was not previoulsy documented. This finding is of clinical interest as AKT has a key role in lymphoma cell survival and constitutive activation of AKT has been described in DLBCL. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Cell-based siRNA screens highlight triple-negative breast cancer cell epigenetic vulnerability

2021 ◽  
Vol 7 (4) ◽  
pp. 196
Author(s):  
Albane Gaudeau ◽  
Coralie Clua Provost ◽  
Thierry Dorval ◽  
Andrew Walsh ◽  
Michael Hannus ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cell Viability ◽  
Cell Survival ◽  
Cell Lines ◽  
Triple Negative Breast Cancer ◽  
Triple Negative ◽  
Knock Down ◽  
Tnbc Cell ◽  
Low Efficiency

<p><strong>Background:</strong> Triple-negative breast cancer (TNBC) is a heterogeneous disease defined by ER-, PR- and HER2-negative phenotype and in most cases, a relatively aggressive clinical behaviour. The lack of specific targeted therapies and low efficiency of currently available chemotherapies spurred several clinical trials in the last few years. Despite encouraging results, TNBC still remains a major unmet medical need that prompted us to explore the role of 863 epigenetic modulators in TNBC cell survival.</p><p><strong>Methods:</strong> A comprehensive siRNA library was screened to explore the role of known epigenetic modulators in TNBC cell viability and growth. The knock-down effect was evaluated for 863 epigenetic genes using 4 siRNAs/gene in two TNBC and a non-TNBC cell lines using ATP-based luminescence and nuclei count image-based assays. Considering siRNA off-target effects, four analysis methods including a classical threshold-based analysis and three ranking methods were applied to determine on-target hits for each screen readout. Hit genes common to both phenotypic readouts highlighted strong epigenetic players involved in TNBC cell survival.</p><p><strong>Results:</strong> Overall, knock-down of many epigenetic modulator genes mitigates cell survival in TNBC and a non-TNBC cell lines depicted from both phenotypic readouts. Interestingly, ranking-based analysis confirmed hit genes identified in threshold-based analysis and also revealed additional hits enabling us to confirm CDK1 and KMT5A as important regulators in TNBC cell viability and growth. Surprisingly, CHAF1A appeared as a new candidate gene involved in TNBC cell survival.</p><p><strong>Conclusions:</strong> Taken together, siRNA epigenetic screening results identified CHAF1A as a novel regulator of TNBC cell survival.</p>

Expression of Lipoprotein Lipase In Chronic Lymphocytic Leukemia Cells: Is There a Biological Function?

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 3580-3580
Author(s):  
Edit anna Porpaczy ◽  
Stefanie Tauber ◽  
Martin Bilban ◽  
Gerhard Kostner ◽  
Michaela Gruber ◽  
...  
Keyword(s):  
Enzymatic Activity ◽  
Cell Survival ◽  
Mrna Expression ◽  
Lipoprotein Lipase ◽  
Cell Lines ◽  
Knock Down ◽  
Protein Levels ◽  
Healthy Donors

Abstract Abstract 3580 The expression of lipoprotein lipase (LPL) in CLL cells is an established mRNA surrogate marker for immunoglobulin heavy chain (IgVH) mutational status. High expression of LPL correlates with poor prognosis. However, the possible functional role of LPL in CLL is still unclear. LPL is normally expressed in muscle cells, adipose tissue and macrophages, transported to the luminal surface of endothelial cells where it is bound heparan sulfate-proteoglycans (HSPG). Heparin competes with HSPG for the binding sites and intravenous injection leads to elevated plasma LPL protein levels and enzymatic activity (“heparin release test”). LPL mRNA levels correlate with intracellular protein expression (Heintel et al. Leukemia. 2005; Mansouri et al. Leuk Res. 2010). Moreover cellular lysates from CLL patients contain elevated LPL enzymatic activity compared to healthy donors (Pallasch et al. Leukemia. 2008.). In this study, we investigated the basal (pre-heparin) LPL protein levels by enzyme-linked immunosorbent assay in the serum of 42 CLL patients, 14 non-CLL patients (lymphoma in remission), and 4 healthy donors (HD): Median pre-heparin LPL protein levels were 40.10 ng/ml (range: 5.66–108.44), 44.11 ng/ml (18.26-84.08), and 68.14 ng/ml (33.28-174.38), respectively. Among CLL patients there were no significant differences between those with high (N=16; median LPL protein in serum: 38.10 ng/ml (8.72-73.49)) and low (N=26; 43.12 ng/ml (5.66-108.44) (p=0.354) LPL mRNA expression. Thirteen patients with known LPL mRNA expression were investigated for LPL protein “release” after heparin injection. Ten and twenty minutes after 50 U/kg heparin injection, the elevation of both parameters, LPL protein amount in serum and enzymatic activity in plasma, was similar to those of HD normal values. In detail, medium serum protein levels in samples with high LPL mRNA (N=5) increased from 16.11 to 214.33 and 332.78 ng/ml and in the samples with low mRNA (N=8) from 13.08 to 219.68 and 386.65 ng/ml, respectively. The corresponding median values of the LPL enzymatic activities in high vs. low expressors were: 7.25/15.52/20.01 and 7.45/19.13/20.57 μ M/ml/h. In addition, release of LPL from peripheral mononuclear cells (PBMC) of CLL patients (N=3) by heparin in vitro was absent. Cell viability and LPL mRNA expression remained unaffected in both in vivo and in vitro samples after heparin addition. In order to assess the impact of LPL on cell survival, CLL cells were cultured (N=3) for up to 72 hours with different doses of purified LPL protein. There was no positive effect on cell survival irrespective of primary LPL mRNA expression or culture conditions (with or without FCS). Since these results point to an intracellular effect of LPL, we aimed to identify downstream targets by knock down with siRNA against LPL in 7 CLL samples and 5 cell lines (hepatocellular carcinoma, cervix carcinoma, colon carcinoma, multiple myeloma and acute monocytic leukemia) with high LPL mRNA expression. Gene expression changes were analyzed by microarrays (GeneChip® Human Gene 1.0 ST Array, Affymetrix). Fifteen genes were up- (N=4) or downregulated (N=11) in at least 3 of 5 cell lines by more than 1.5-fold (e.g. GSTP1, COROC1). Nine genes were at least 1.5-fold downregulated in parallel with LPL in the CLL samples only. These genes belong to various pathways (e.g. cell cycle, signaling in immune system, metabolism of carbohydrates) and seem to be specific for CLL. Cross-validation of individual genes is under way. Our data suggest that (1) neither basal serum LPL protein levels nor heparin-induced LPL release in CLL patients are suitable clinical prognostic markers; (2) Stimulation with external LPL protein does not affect CLL cell survival; (3) siRNA knock-down of LPL induces changes in various functional pathways. We conclude that the key role of LPL expression in high-risk CLL is related to its (intra)cellular expression. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Smoothened Stabilizes and Protects TRAF6 from Proteosomal Degradation: A Novel Non-Canonical Role of Smoothened with Implications in Lymphoma Biology

Blood ◽  
2017 ◽  
Vol 130 (Suppl_1) ◽  
pp. 646-646
Author(s):  
Changju QU ◽  
Amineh Vaghefi ◽  
Kranthi Kunkalla ◽  
Jennifer R Chapman ◽  
Yadong Liu ◽  
...  
Keyword(s):  
Cell Survival ◽  
Cell Lines ◽  
E3 Ligase ◽  
B Cell Lymphoma ◽  
Mrna Levels ◽  
Protein Levels ◽  
Multiple Cancers ◽  
Proteosomal Degradation ◽  
Hh Signaling

Abstract Tumor necrosis factor receptor-associated factor 6 (TRAF6), an (K63) E3-ligase, plays a crucial role in many biological processes and its activity is relevant in the biology of multiple cancers including diffuse large B cell lymphoma (DLBCL). Although molecules that trigger TRAF6 activation have been defined, those that stabilize TRAF6 levels and/or enhance TRAF6 function remain largely unclear. Previously, we found that activation of smoothened (SMO) with recombinant Hedgehog (Hh) ligand increased the binding between SMO with TRAF6, as well as TRAF6 protein levels (Blood 2013; 121:4718-28). In addition, transient overexpression of SMO resulted in increased K63-Ub of both TRAF6 and NEMO indicating stabilization of these proteins resulting in NF-kB activation. This is relevant, as more recently we found that TRAF6 amplifies pAKT signaling in DLBCL and that TRAF6 is the dominant E3 ligase for the K63-Ub of AKT in DLBCL. Moreover, TRAF6 recruitment to the cell membrane, and stabilization of its ubiquitination profile are facilitated by SMO. SMO is a member of the Frizzled-class G-protein-coupled receptor (GPCRs) and is traditionally known for its role as signal transducer in canonical Hedgehog (Hh) signaling. These observations prompted us to investigate whether the ability of SMO to increase TRAF6 levels is limited to ligand induced signaling, whether it contributes to chemoresistance in DLBCL cells, and whether SMO directly participates in controlling TRAF6 levels. To confirm the regulatory role of SMO in the TRAF6/AKT axis in DLBCL cells (HBL1 and HT) and further outline the nature of the underlying regulation, we measured the impact of activation of the Hh pathway with recombinant Shh ligand on TRAF6 levels, with and without SMO knockdown or recombinant SMO overexpression. Canonical Hh signaling results in the activation of the GLI1 transcription factor and the subsequent elevation of GLI1 mRNA levels is an established indicator of activation of the Hh pathway. However, neither SMO activation nor the knockdown of GLI1 had a significant impact on TRAF6 mRNA levels. These findings indicate that TRAF6 is not transcriptionally regulated by SMO signaling through GLI1 (canonical Hh signaling). In contrast, overexpression of SMO or siRNA knockdown of SMO resulted in an increase or decrease of TRAF6 protein levels, respectively. Consistent with the decrease of AKT activation (pAKT T308 and S473) after TRAF6 knockdown, the increase in TRAF6 levels that follows SMO overexpression resulted in an increase in the levels of AKT phosphorylation. Altogether, these observations suggest a post-translational regulation of TRAF6 by SMO. Indeed, stable knockdown of SMO dramatically reduces the half-life of TRAF6 in both HBL1 and HT cells in the presence of cyclohexamide. Furthermore, overexpression of SMO increases K63-Ub of both TRAF6 and AKT. In contrast, the SMO induced decrease in K48-Ub occurred only for TRAF6 but not for AKT. These data link the SMO-stimulated activation of TRAF6 to the enhancement of AKT signaling and protection of TRAF6 from proteasomal degradation. Mechanistically, we found that SMO, through its C-terminal tail, stabilizes TRAF6 and protects TRAF6 from proteosomal degradation, an effect mediated by ubiquitin-specific protease-8 (USP8). Importantly, this functional link between SMO and TRAF6 is reflected in DLBCL patient samples where high expression of both molecules correlates with poor prognosis. Resistance to DXR is a serious challenge in the treatment of DLBCL, and activated AKT is known to contribute to DXR resistance in multiple cancers including DLBCL. We evaluated whether SMO and TRAF6 support resistance to DXR in DLBCL cell lines. We exposed HT and HBL1 cells as well as their counterparts with stable knockdown of TRAF6 or SMO to DXR for 96hrs. Cell viability after exposure to DXR was determined by an Annexin V and PI staining assay. Silencing SMO or TRAF6 dramatically decreased cell survival after treatment with DXR. In summary, we report that SMO is needed to facilitate and maintain TRAF6-dependent elevated pAKT levels in DLBCL cell lines of germinal (GC) and non-GC subtypes, and that the SMO/TRAF6 axis contributes to DXR resistance in DLBCL. Our study reveals a novel and potential central cell survival signaling mechanism in which SMO stabilizes and protects TRAF6 from proteosomal degradation. Disclosures Lossos: Affimed: Research Funding.

scholarly journals Serine/Threonine Kinase 35, a Target Gene of STAT3, Regulates the Proliferation and Apoptosis of Osteosarcoma Cells

2018 ◽  
Vol 45 (2) ◽  
pp. 808-818 ◽  
Author(s):  
Zhong Wu ◽  
Jie Liu ◽  
Siyuan Hu ◽  
Yuchang Zhu ◽  
Shaohua Li
Keyword(s):  
Mrna Expression ◽  
Real Time ◽  
Real Time Pcr ◽  
Gene Set Enrichment Analysis ◽  
Cell Counting ◽  
Luciferase Reporter ◽  
Osteosarcoma Cells ◽  
Serine Threonine Kinase ◽  
Threonine Kinase ◽  
Proliferation And Apoptosis

Background/Aims: Serine/threonine kinase 35 (STK35) may be associated with Parkinson disease and human colorectal cancer, but there have been no reports on the expression levels or roles of STK35 in osteosarcoma. Methods: STK35 mRNA expression was determined in osteosarcoma and bone cyst tissues by real-time PCR. Cell proliferation and apoptosis were assessed by Cell Counting Kit-8 (CCK-8) assay and flow cytometry analysis, respectively. Results: STK35 was up-regulated in osteosarcoma tissues as indicated by analyzing publicly available expression data (GEO dataset E-MEXP-3628) and real-time PCR analysis on our own cohort. We subsequently investigated the effects of STK35 knockdown on two osteosarcoma cell lines, MG63 and U2OS. STK35 knockdown inhibited the growth of osteosarcoma cells in vitro and in xenograft tumors. Meanwhile, STK35 knockdown enhanced apoptosis. Expression of the active forms and the activity of two major executioner caspases, caspase 3 and caspase 7, were also increased in osteosarcoma cells with STK35 silenced. Additionally, Gene Set Enrichment Analysis (GSEA) identified that the JAK/STAT signaling pathway was positively correlated with STK35 expression. The mRNA expression of STK35 was repressed by STAT3 small interfering RNA (siRNA), but not by siRNA of STAT4, STAT5A or STAT6. A luciferase reporter assay further demonstrated that STAT3 transcriptionally regulated STK35 expression. A chromatin immunoprecipitation (ChIP) assay confirmed the direct recruitment of STAT3 to the STK35 promoter. The promotion effects of STAT3 knockdown on cell apoptosis were partially abolished by STK35 overexpression. Furthermore, STK35 mRNA expression was positively correlated with STAT3 mRNA expression in osteosarcoma tissues by Pearson correlation analysis. Conclusions: These results collectively reveal that STAT3 regulates the transcription of STK35 in osteosarcoma. STK35 may exert an oncogenic role in osteosarcoma.

scholarly journals MiR-624-5p enhances cell resistance against cisplatin via PDGFRA/Stat3/PI3K axis in ovarian cancer

2020 ◽  
Vol 19 (4) ◽  
pp. 691-698
Author(s):  
Lin I-Ju ◽  
Tian YongJie
Keyword(s):  
Ovarian Cancer ◽  
Cell Viability ◽  
Cell Line ◽  
Cell Lines ◽  
Clinical Stage ◽  
Luciferase Reporter Assay ◽  
Luciferase Reporter ◽  
Reporter Assay

Purpose: The purpose of this study was to evaluate the role of miR-624-5p in ovarian cancer.Methods: MiR-624-5p expression in ovarian cancer {OC) cell lines and normal cells (NCs) was evaluated and compared the differential miR-624-5p in OC A2780 cells and cisplatin-resistant OC cell line (A2780/DDP). CCK-8 was used to evaluate changes in cell viability of the A2780 and A2780/DDP cell lines as well as silenced miR-624-5p. Western Blot examined the Stat3 and phosphorylated Pi3k. The binding between PDGFRA and miR-624-5p was predicted on Targetscan and verified through Luciferase Reporter Assay. The role of PDGFRA in A2780/DDP by overexpressing PDGFRA was evaluated by RT-qPCR and CCK-8 assays. RT-qPCR assay also measured miR-624-5p expression responsive to different dosages of cisplatin and CCK8 examined viability levels correspondingly. In addition, the interplay of PDGFRA and miR-624-5p by combined downregulation of both miR-624-5pand PDGFRA were evaluated.Results: OC cells had higher miR-624-5p expression than NCs but lower compared to cisplatinresistant A2780/DDP cells. A2780/DDP cells had higher viability than OC cell line A2780. Stat3 and phosphorylated PI3K were activated in A2780/DDP cells. Silencing miR-624-5p led to lower viability inA2780/DDP cells. miR-624-5p expression dropped as the cisplatin concentration increased, resulting in decreasing viability respectively. Luciferase Reporter assay validated the binding of miR-624-5p and PDGFRA in A2780/DDP cells. Overexpressed PDGFRA induced lower cell viability in A2780/DDP cells. Downregulation of PDGFRA partially restored the lowered viability and inhibited Stat3 as well as phosphorylated Pi3k induced by miR-624-5p inhibitor.Conclusion: MiR-624-5p could add to the cellular resistance to cisplatin in OC in-vitro model, which indicated that it might help unveil the mystery of drug-resistance in clinical stage of ovarian cancer. Keywords: MiR-624-5p, resistance, cisplatin, PDGFRA/Stat3/PI3K, ovarian cancer

The role of methylation leading to capecitabine resistant malignant mesothelioma

2006 ◽  
Vol 24 (18_suppl) ◽  
pp. 17105-17105 ◽  
Author(s):  
K. V. Kosuri ◽  
X. Wu ◽  
G. Otterson
Keyword(s):  
Real Time ◽  
Cell Lines ◽  
Malignant Mesothelioma ◽  
Mtt Assay ◽  
Real Time Pcr ◽  
Dihydropyrimidine Dehydrogenase ◽  
Relative Difference ◽  
Western Blots ◽  
Mesothelioma Cell

17105 Background: Malignant mesothelioma is a deadly malignancy whose global incidence continues to be on the rise. Established therapies have been less than optimal. The current therapeutic standard is intravenous pemetrexed, an antifolate medication. Yet, another folate antimetabolite, capecitabine, is significantly less effective than pemetrexed. The enzymes thymidylate synthase (TS), dihydropyrimidine dehydrogenase (DPD), and thymidylate phosphatase (TP) are critical to the efficacy of antifolates. Specifically, for capecitabine to be converted into a potent cytotoxic agent, the enzyme TP must be present and active. In one of four mesothelioma cell lines examined, the gene that encodes for TP, extracellular growth factor-1 (ECGF-1), is methylated. Methylation of this gene and the subsequent downregualtion of the TP enzyme confer a diminished cytotoxic effect by a capecitabine prodrug, dioxyfluridine (DFUR). Methods: Cells were cultured treated with and without 1uM decitabine (DAC) under identical conditions. DNA, RNA, and protein lysates were collected after 72 hours. Bisulfite-treated DNA was examined by MS-PCR for evidence of methylation of TS, DPD, and TP. RNA was collected and cDNA was synthesized. Real time PCR was utilized to detect the relative difference in RNA quantity. Western blots were done to evaluate the differences in protein expression between DAC treated and untreated cells. MTT assay was performed with DAC pretreated and untreated cell lines subsequently treated with DFUR and 5-fluorouracil. Results: One of the four mesothelioma cell lines showed consistent evidence of TP methylation by MS-PCR. The addition of 1uM DAC to the cell lines conferred a six-fold difference in expression of the methylated gene by both real time PCR as well as by Western blot. The prodrug DFUR subsequently shows increased cytotoxicity in the methylated cell line by MTT assay when pretreated with DAC compared when not exposed to the DAC. Conclusion: By demethylating the ECGF-1 gene with DAC, the now upregulated TP enzyme has an increased ability to convert DFUR to 5-FU; thus enhancing the cytotoxicity of a drug thought to be ineffective in malignant mesothelioma. No significant financial relationships to disclose.

scholarly journals MicroRNA-103 Promotes Proliferation and Inhibits Apoptosis in Spinal Osteosarcoma Cells by Targeting p57

2018 ◽  
Vol 26 (6) ◽  
pp. 933-940 ◽  
Author(s):  
Xuesong Wang ◽  
Yong Lin ◽  
Lei Peng ◽  
Ruifu Sun ◽  
Xiaojin Gong ◽  
...  
Keyword(s):  
Cell Survival ◽  
Cell Lines ◽  
Poor Prognosis ◽  
Luciferase Reporter ◽  
Migration And Invasion ◽  
Reporter Assay ◽  
Osteosarcoma Cells ◽  
Binding Effect ◽  
Mg63 Cells

Osteosarcoma is one of the most aggressive malignancies with poor prognosis rates. Many studies have demonstrated that miRNAs were involved in osteosarcoma, but the role of miR-103a in osteosarcoma remains elusive. In this study, we detected the expression levels of miR-103 in osteosarcoma and non-osteosarcoma tissues and cell lines. The binding effect of miR-103 on p57 was detected by luciferase reporter assay. After altering expressions of miR-103 or p57, viability, migration, invasion, and apoptosis of MG63 cells and expressions of proteins related with the JNK/STAT and mTOR pathways were all detected. We found the higher expression of miR-103 in osteosarcoma tissues and cell lines compared with non-osteosarcoma tissues and cell lines. miR-103 overexpression promoted survival, migration, and invasion of MG63 cells. Knockdown of miR-103a inhibited cell survival, migration, and invasion by upregulating the expression of p57, which was a target of miR-103. Moreover, miR-103a overexpression activated the JNK/STAT and mTOR pathways probably through inhibiting p57 expression. In conclusion, miR-103a acted as an oncogene in osteosarcoma, probably through activating the JNK/STAT and mTOR pathways by inhibiting p57 expression.

scholarly journals Homeobox Transcription Factor Hhex Promotes Myeloid Leukemia in Cooperation with Mutant ASXL1

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 2525-2525
Author(s):  
Reina Takeda ◽  
Shuhei Asada ◽  
Sung-Joon Park ◽  
Akihiko Yokoyama ◽  
Akinori Kanai ◽  
...  
Keyword(s):  
Mrna Expression ◽  
Cell Lines ◽  
Myeloid Leukemia ◽  
Gene Set Enrichment Analysis ◽  
Leukemia Cells ◽  
Luciferase Reporter ◽  
Human Leukemia ◽  
Rna Seq ◽  
Hematopoietic Stem

Additional sex combs-like 1 (ASXL1) mutations are frequently found in myeloid malignancies such as AML, MDS and MPNs. Our previous study on mutant Asxl1 expressing knock-in (Asxl1-MT KI) mice revealed that Asxl1-MT impaired normal hematopoiesis (Nagase R et al. J. Exp. Med. 2018). However, Asxl1-MT alone was insufficient to develop myeloid leukemia. Thus, additional factors are required for myeloid transformation in ASXL1-mutated cells. Retrovirus-mediated insertional mutagenesis approaches demonstrated susceptibility of Asxl1-MT KI cells to myeloid leukemia, and helped identifying Hematopoietically expressed homeobox (Hhex) gene as a common retrovirus integration site. Therefore, we here investigated the potential cooperation between ASXL1-MT and HHEX in myeloid leukemogenesis. We first assessed the effects of ASXL1-MT and HHEX on proliferation and differentiation of murine and human hematopoietic stem progenitor cells (HSPCs). Expression of HHEX enhanced proliferation and blocked differentiation of HSPCs expressing ASXL1-MT, while it showed only a modest effect in normal HSPCs. Some of the mice transplanted with cells expressing ASXL1-MT and HHEX developed myeloid leukemia. Expression of ASXL1-MT and HHEX dramatically promoted the growth of RUNX1-ETO-expressing Cord Blood (CB) cells in vitro by promoting cell cycle and inhibiting apoptosis. Moreover, ASXL1-MT and HHEX synergistically accelerated development of two distinct types of myeloid leukemia driven by RUNX1-ETO9a or FLT3-ITD in vivo. These data indicate that ASXL1-MT and HHEX cooperatively work in leukemic transformation of myeloid cells. Next, we evaluated the role of endogenous HHEX in ASXL1-MT-expressing leukemia cells. We here used two murine mutant ASXL1-expressing leukemia cells (cSAM cells: cells with combined expression of SETBP1 and ASXL1 mutations, cRAM cells: cells with combined expression of RUNX1 and ASXL1 mutations). Depletion of Hhex using CRISPR-Cas9 system profoundly attenuated the colony-forming ability and leukemogenicity of cSAM and cRAM cells. Similarly, depletion of HHEX attenuated the growth of human leukemia cell lines harboring an ASXL1 mutation including MEG-01 and Kasumi-1 by inducing apoptosis and differentiation. In contrast, the growth of ASXL1 wildtype cell lines such as THP-1 and U937 was unaffected by HHEX depletion. Thus, endogenous HHEX promotes survival of ASXL1-mutated leukemia cells. To elucidate the underlying molecular mechanisms, we performed RNA-seq using RUNX1-ETO expressing CB cells. Gene set enrichment analysis revealed that genes related to leukemia stem cells were more enriched in cells expressing both ASXL1-MT and HHEX than control cells. In combination with this RNA-seq data and ChIP-seq using 293T cells, we identified Myb and Etv5 as candidate genes upregulated by HHEX expression. We confirmed that ASXL1-MT and HHEX upregulated Myb and Etv5 in murine HSPCs by RT-qPCR and HHEX bound to promoter regions of MYB and ETV5 genes in HL-60 cells by ChIP-qPCR. Conversely, depletion of Hhex reduced expression of Myb and Etv5 in cSAM and cRAM cells. Luciferase reporter assay revealed that co-expression of ASXL1-MT and HHEX cooperatively enhanced promoter activity of MYB. In addition, preliminary expression analyses of primary cells showed that HHEX/ETV5 mRNA expression levels were significantly and MYB mRNA expression tended to be higher in primary AML samples including ASXL1 mutations compared to the ones of healthy controls (Beat AML). Finally, we assessed the role of MYB or ETV5 in leukemogenesis driven by ASXL1 mutations. Depletion of Myb or Etv5 reduced colony-forming activity in cSAM and cRAM cells by promoting apoptosis or differentiation, respectively. Furthermore, ectopic expression of MYB or ETV5 significantly reversed the reduced colony-forming activity of Hhex-depleted cSAM cells. Taken together, our study demonstrates that ASXL1-MT and HHEX are cooperative events promoting myeloid leukemogenesis through upregulation of MYB and ETV5. Disclosures Maciejewski: Novartis: Consultancy; Alexion: Consultancy.

Expression and Role of APP Gene in Acute Myeloid Leukemia.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 4691-4691
Author(s):  
Fanyi Meng ◽  
Wei Wang ◽  
Zoufang Huang ◽  
Ming Huang ◽  
Lixiang Liu
Keyword(s):  
Cell Cycle ◽  
Acute Myeloid Leukemia ◽  
Western Blot ◽  
Real Time ◽  
Cell Lines ◽  
Real Time Pcr ◽  
Myeloid Leukemia ◽  
App Gene ◽  
Acute Myeloid

Abstract Abstract 4691 Introduction Amyloid precursor protein(APP) gene was increasingly expressed in solid tumors, promoted the proliferation of tumor cells and the overexpression of APP was a bad prognostic factor to oral squamous cell carcinoma. However, little has been known about the clinical significance and role of APP in acute myeloid leukemia(AML). Methods The expressions of APP mRNA in 85 AML patients and 20 nonmalignant hematological diseases that worked as control were measured by real-time PCR and the expressions of APP in AML cell lines were examined by real-time PCR and western blot. Small interfering RNAs(siRNAs) targeting APP gene were synthesized and transfected into HL60 cell by lipofectamine2000, after RNAi 24h, 48h and 72h, cell growth of HL60 was measured by trypan blue dye exclusion method and MTT, differentiation was observed by Wright-Giemsa staining, cell cycle was examined by PI/RNase staining, apoptosis induction was analyzed by Annexin V/PI and Hoechst33342 staining; apoptosis-related proteins NF-κB, bcl-2 and Caspase-3 were detected by Western blot after RNAi 48h; sensitivity of HL60 to adrimycin was measured by MTT. Results The expression of APP mRNA among AML subtypes was significantly different(P=0.019), M2 with t(8;21) was the highest expression subtype and M5b was the lowest. APP expression had no significant effect on AML clinical characteristic excepting AML subtypes. kasumi-1 was the highest expression cell in AML cell lines and U937 was the lowest(P<0.05), and the expression of APP in HL60/ADM was significantly lower than HL60(P<0.05). The APP expressions in AML cell lines was in agreement with its expressions in primary AML subtypes. After RNAi 24h, 48h, and 72h, no significant differences in proliferation, differentiation, apoptosis, cell cycle and sensitivity of HL60 to adriamycin were detected between interfering group and control groups. Conclusions The APP mRNA expression in M2 with t(8;21) was high and M5b was low. Down-regulation of APP expression had no significant effect on biological behaviour of HL60 and APP was not tightly related to pathogenesis of AML. Disclosures: No relevant conflicts of interest to declare.

scholarly journals miR-455 Inhibits the Viability and Invasion by Targeting RAB18 in Hepatocellular Carcinoma

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Chenghong Wang ◽  
Guicai Zhu ◽  
Miaolin Yu ◽  
Xiufang Mi ◽  
Honghua Qu
Keyword(s):  
Hepatocellular Carcinoma ◽  
Cell Viability ◽  
Cell Lines ◽  
Luciferase Reporter ◽  
Common Cancer ◽  
Huh7 Cells ◽  
Proliferation In Vitro

Background. Hepatocellular carcinoma (HCC) has been regarded as the fifth most common cancer worldwide with a low prognosis. miR-455 usually played the role of a tumor suppressor in multiple cancers. The aim of this study was to investigate the roles of miR-455 in HCC. Materials and Methods. Cell viability and invasion were measured by CCK8 and Transwell assays. Luciferase reporter assay was performed to verify that miR-455 directly binds to the 3′-noncoding region (UTR) of RAB18 mRNA in Huh7 cells. Results. The expression of miR-455 was lower in HCC tissues and cell lines than in nontumor tissues and normal cell line, and downregulation of miR-455 was connected with worse outcome of HCC patients. miR-455 suppressed cell proliferation in vitro and in vivo, and it inhibited the abilities of cell invasion and EMT in HCC. RAB18 was upregulated in HCC tissues and cell lines, and the expression of RAB18 was regulated by miR-455. RAB18 reversed partial roles of miR-455 on cell viability and invasion in HCC. Conclusion. miR-455 inhibited cell viability and invasion by directly targeting the 3′-UTR of RAB18 mRNA of hepatocellular carcinoma.

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