Role of Different C/EBPα Mutations in AML Transformation.

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 1343-1343
Author(s):  
Oscar Quintana-Bustamante ◽  
S. Lan-Lan Smith ◽  
Jude Fitzgibbon ◽  
Dominique Bonnet
Keyword(s):  
Cell Cycle ◽  
Cell Proliferation ◽  
Cell Cycle Arrest ◽  
Myeloid Differentiation ◽  
Granulocytic Differentiation ◽  
Self Renewal ◽  
Cycle Arrest

Abstract Acute Myeloid Leukemia (AML) is characterized by an abnormal hematopoietic differentiation and uncontrolled cell proliferation. Mutations in several transcription factors (TFs) have been implicated in the development of leukemia. One of these TFs is CCAAT/enhancer-binding protein-α (C/EBPα). In normal hematopoiesis, C/EBPα plays a central role to coordinate myeloid differentiation and growth arrest. C/EBPα is mutated in approximately 9% of AML; these mutations take place either in C or N terminal domains of the protein, although there are several familial cases of AML where both types of mutations have been found. We use C and/or N terminal C/EBPα mutations from one case of sporadic AML to investigate the role of each mutation in leukemic transformation (Smith et al., 2004, N Engl J Med 351, 2403–2407). Human lineage negative (Lin-) umbilical cord blood were transduced with lentiviral vectors carrying the wild type C/EBPα (WT), N terminal mutated C/EBPα (N-ter) or N and C terminal mutated (NC-ter) C/EBPα cloned from this sporadic case of AML. We observed differences in proliferation of transduced Lin- in vitro: WT C/EBPα expression resulted in G0 cell cycle arrest causing a progressive extinction of the transduced cells overtime; N-ter cells showed a higher proliferative advantage over untransduced cells. The NC-ter CEBPα cells like untransduced cells kept their levels throughout culture. Furthermore, when induced into myeloid differentiation in vitro, WT C/EBPα cells were mainly inducing fully mature granulocytes whereas N-ter C/EBPα was not able to induce terminal granulocytic differentiation; in contrast NC-ter C/EBPα did not increase myeloid differentiation. Additionally, their ability to form Colony Forming Units (CFUs) in primary, secondary and tertiary replating was also tested: WT transduced cells gave rise to few primary CFUs; contrary, N and NC-ter could generate both primary and secondary CFUs, but only NC-ter cells were able to produce CFUs in tertiary replating, indicating its ability to maintain undifferentiated hematopoietic progenitors in vitro. These results were confirmed using Long-Term Culture Initiating Cells (LTC-IC) where the NC-ter mutated cells showed the highest LTC-IC after 5 weeks. Finally, in vivo transplantation in NOD/SCID/β2mnull indicated that NC-ter mutated cells engraft better than WT and N-ter 8 week post- transplant. Serial transplantation experiments are underway to evaluate their self-renewal capacity. Our results confirmed some known functions of WT C/EBPα in human hematopoiesis, such as inducing myeloid differentiation and cell cycle arrest. On the other hand, we showed new functions for the C/EBPα mutants. The N-ter C/EBPα mutation caused an increase in cell proliferation and blockage of terminal granulocytic differentiation, whereas the NC-ter C/EBPα mutation increased the self-renewal capacity of progenitor/stem cells without having an influence on myeloid differentiation. This work provides further insight into the mechanisms by which different C/EBPα mutations induce AML.

scholarly journals Silencing or inhibition of H3K79 methyltransferase DOT1L induces cell cycle arrest by epigenetically modulating c-Myc expression in colorectal cancer

2019 ◽  
Vol 11 (1) ◽  
Author(s):  
Liqun Yang ◽  
Qian Lei ◽  
Lin Li ◽  
Jie Yang ◽  
Zhen Dong ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Cell Cycle ◽  
Cell Proliferation ◽  
Cell Cycle Arrest ◽  
S Phase ◽  
Self Renewal ◽  
Cycle Arrest ◽  
H3k79 Methylation

Abstract Background Epigenetic regulations play pivotal roles in tumorigenesis and cancer development. Disruptor of telomeric silencing-1-like (DOT1L), also known as KMT4, is the only identified histone methyltransferase that catalyzes the mono-, di-, and tri-methylation of lysine 79 histone 3 (H3K79). However, little is known about the effect of H3K79 methylation on the modulation of colorectal cancer (CRC) development. Methods DOT1L expression profiles in different subgroups of CRC tissues and its clinical significances were analyzed from some online datasheets. DOT1L in CRC cell lines was silenced by either lentivirus-mediated knockdown or inhibited by its specific inhibitor, EPZ004777. Then cell proliferation was detected by MTT assay, BrdU assay, and soft agar assay; cell cycle was detected by cytometry; and tumorigenicity was detected by using nude mice xenograft models. Clinical co-expression was analyzed between DOT1L and c-Myc. Chromatin immunoprecipitation (ChIP) assay was used to determine whether the translation of c-Myc was epigenetically regulated by H3K79me2 induced by DOT1L. c-Myc overexpression was used to rescue the cell cycle arrest and tumor growth induced by DOT1L silencing or inhibition in CRC. Results We found that DOT1L was highly expressed in colorectal cancer and was negatively related to the prognosis of patients with CRC. Silencing or inhibition of DOT1L blocked cell proliferation, BrdU incorporation, self-renewal capability in vitro, and tumorigenicity in vivo. Besides, inhibition or silencing of DOT1L also induced cell cycle arrest at S phase, as well as decreased the expression of CDK2 and Cyclin A2. Furthermore, in the clinical databases of CRC, we found that the expression of DOT1L was positively correlated with that of c-Myc, a major regulator in the upstream of cell cycle–related factors. Besides, c-Myc expression was downregulated after DOT1L knockdown and c-Myc restoration rescued decrease of cell proliferation, BrdU corporation, self-renewal capability, cell cycle progression in vitro and tumorigenicity in vivo induced by DOT1L silencing. Then we found that H3K79 methylation was decreased after DOT1L knockdown. ChIP assay showed that H3K79me2 was enriched on the – 682~+ 284 region of c-Myc promoter, and the enrichment was decreased after DOT1L inhibition. Conclusions Our results show that DOT1L epigenetically promotes the transcription of c-Myc via H3K79me2. DOT1L silencing or inhibition induces cell cycle arrest at S phase. DOT1L is a potential marker for colorectal cancer and EPZ004777 may be a potential drug for the treatment of colorectal cancer.

scholarly journals CCT Chaperonin Complex Is Required for the Biogenesis of Functional Plk1

2005 ◽  
Vol 25 (12) ◽  
pp. 4993-5010 ◽  
Author(s):  
Xiaoqi Liu ◽  
Chin-Yo Lin ◽  
Ming Lei ◽  
Shi Yan ◽  
Tianhua Zhou ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Proliferation ◽  
Cell Cycle Arrest ◽  
Mammalian Cells ◽  
Active Form ◽  
Cycle Arrest ◽  
Cdc2 Activity ◽  
Partial Depletion

ABSTRACT Experiments from several different organisms have demonstrated that polo-like kinases are involved in many aspects of mitosis and cytokinesis. Here, we provide evidence to show that Plk1 associates with chaperonin-containing TCP1 complex (CCT) both in vitro and in vivo. Silencing of CCT by use of RNA interference (RNAi) in mammalian cells inhibits cell proliferation, decreases cell viability, causes cell cycle arrest with 4N DNA content, and leads to apoptosis. Depletion of CCT in well-synchronized HeLa cells causes cell cycle arrest at G2, as demonstrated by a low mitotic index and Cdc2 activity. Complete depletion of Plk1 in well-synchronized cells also leads to G2 block, suggesting that misfolded Plk1 might be responsible for the failure of CCT-depleted cells to enter mitosis. Moreover, partial depletion of CCT or Plk1 leads to mitotic arrest. Finally, the CCT-depleted cells reenter the cell cycle upon reintroduction of the purified constitutively active form of Plk1, indicating that Plk1 might be a CCT substrate.

scholarly journals Dysregulation of miR-23b-5p promotes cell proliferation via targeting FOXM1 in hepatocellular carcinoma

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Xinchen Yang ◽  
Shikun Yang ◽  
Jinhua Song ◽  
Wenjie Yang ◽  
Yang Ji ◽  
...  
Keyword(s):  
Hepatocellular Carcinoma ◽  
Cell Cycle ◽  
Cell Proliferation ◽  
Cell Cycle Arrest ◽  
Tumor Development ◽  
Loss Of Function ◽  
Cycle Arrest ◽  
Cell Proliferation Inhibition

AbstractGrowing evidence demonstrates that MicroRNAs (miRNAs) play an essential role in contributing to tumor development and progression. However, the underlying role and mechanisms of miR-23b-5p in hepatocellular carcinoma (HCC) formation remain unclear. Our study showed that miR-23b-5p was downregulated in the HCC tissues and cell lines, and lower expression of miR-23b-5p was associated with more severe tumor size and poorer survival. Gain- or loss-of-function assays demonstrated that miR-23b-5p induced G0/G1 cell cycle arrest and inhibited cell proliferation both in vitro and in vivo. qRT-PCR, western blot and luciferase assays verified that Mammalian transcription factor Forkhead Box M1 (FOXM1), upregulated in HCC specimens, was negatively correlated with miR-23b-5p expression and acted as a direct downstream target of miR-23b-5p. In addition, miR-23b-5p could regulate cyclin D1 and c-MYC expression by directly targeting FOXM1. Further study revealed that restoration of FOXM1 neutralized the cell cycle arrest and cell proliferation inhibition caused by miR-23b-5p. Taken together, our findings suggest that miR-23b-5p acted as a tumor suppressor role in HCC progression by targeting FOXM1 and may serve as a potential novel biomarker for HCC diagnosis and prognosis.

scholarly journals Glaucocalyxin A suppresses multiple myeloma progression in vitro and in vivo through inhibiting the activation of STAT3 signaling pathway

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Mei Li ◽  
Cailong Chen ◽  
Qian Wang ◽  
Xiaolu Jiang ◽  
Lanlan Tan ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Multiple Myeloma ◽  
Cell Proliferation ◽  
Xenograft Model ◽  
Mice Model ◽  
Cycle Arrest ◽  
Nude Mice Model

Abstract Background Multiple myeloma (MM) is the most common malignant hematological disease in the people worldwide. Glaucocalyxin A (GLA) is a bioactive ent-kauranoid diterpenoid, that is derived from Rabdosia japonica var. GLA has been demonstrated that it had various pharmacological activities, such as anti-coagulation, anti-bacterial, anti-tumor, anti-inflammation, antioxidant activities. Although GLA has effective anti-tumor properties, its effects on multiple myeloma remain unclear. The aim of this study was to examine the possible anti-cancer effects of GLA and their molecular mechanisms on MM cells in vitro and in vivo. Methods To evaluate the role of GLA on the proliferation of MM cells in vitro and in vivo, we used MTT method to detect the role of GLA on the proliferation of MM cells. Cell apoptosis and cell cycle assay were evaluated by flow cytometry. Protein expressions in GLA-treated and untreated MM cells were evaluated by western blot analyses. MM xenograft nude mice model was used to investigate the role of GLA on the proliferation of MM cells in vivo. IHC assay was used to examine the role of GLA on the MM xenograft model in vivo. Results In the present study, we firstly reported the potent anti-myeloma activity of GLA on MM cells. We found that GLA could induce apoptosis in vitro and in vivo. GLA could inhibit the phosphorylation of the signal transducer and activator of transcription 3 (STAT3) and downregulate interleukin IL-6 induced STAT3 phosphorylation in MM. Overexpression of STAT3 could significantly prevent apoptosis induced by GLA; while knockdown of STAT3 enhanced it. Moreover, GLA could inhibit cell proliferation by inducing the cell cycle arrest. GLA reduced the expression of cell cycle-related proteins CCNB1, CCND1, CCND2, and CCND3 and increased the expression of p21 in MM cell lines. In addition, in the MM xenograft nude mice model, GLA exhibited very good anti-myeloma activity. Administration of GLA almost completely inhibited tumor growth within 19 days without physical toxicity. And the IHC results showed GLA significantly inhibited cell proliferation and interfered STAT3 pathway on MM xenograft model tumor tissues. Conclusions Taken together, our present research indicated that GLA inhibits the MM cell proliferation, induces MM cell apoptosis and cell cycle arrest through blocking the activation of STAT3 pathway. Thus, GLA may be a potential therapeutic candidate for MM patients in the future.

scholarly journals Aspirin inhibits cholangiocarcinoma cell proliferation via cell cycle arrest in vitro and in vivo

2020 ◽  
Vol 58 (2) ◽  
pp. 199-210
Author(s):  
Tingting Shi ◽  
Jian Gong ◽  
Koji Fujita ◽  
Noriko Nishiyama ◽  
Hisakazu Iwama ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Proliferation ◽  
Cell Cycle Arrest ◽  
Cycle Arrest ◽  
Cholangiocarcinoma Cell

scholarly journals Crocin Exhibits Antitumor Effects on Human Leukemia HL-60 Cells In Vitro and In Vivo

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Yan Sun ◽  
Hui-Juan Xu ◽  
Yan-Xia Zhao ◽  
Ling-Zhen Wang ◽  
Li-Rong Sun ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Proliferation ◽  
Cell Cycle Arrest ◽  
Nude Mice ◽  
Dependent Manner ◽  
Antitumor Effects ◽  
Tumor Weight ◽  
Cycle Arrest

Crocin is a carotenoid of the saffron extract that exhibits antitumor activity against many human tumors. However, the effects of crocin on HL-60 cells in vivo have not been evaluated. This study aimed to examine the effects of crocin on HL-60 cells in vitro and in vivo and investigate the underlying mechanisms. HL-60 cells were treated by crocin, and cell proliferation, apoptosis, and cell cycle profiles were examined by MTT assay, AO/EB staining, and flow cytometry, respectively. Furthermore, HL-60 cells were xenografted into nude mice and treated by crocin, the tumor weight and size were calculated, and the expression of Bcl-2 and Bax in xenografts was detected by immunohistochemical staining. The results showed that crocin (0.625–5 mg/mL) inhibited HL-60 cell proliferation and induced apoptosis and cell cycle arrest at G0/G1 phase, in a concentration and time-dependent manner. In addition, crocin (6.25, 25 mg/kg) inhibited the tumor weight and size of HL-60 xenografts in nude mice, inhibited Bcl-2 expression, and increased Bax expression in xenografts. In summary, crocin inhibits the proliferation and tumorigenicity of HL-60 cells, which may be mediated by the induction of apoptosis and cell cycle arrest and the regulation of Bcl-2 and Bax expression.

scholarly journals Circ_0000745 strengthens the expression of CCND1 by functioning as miR-488 sponge and interacting with HuR binding protein to facilitate the development of oral squamous cell carcinoma

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Kuangzheng Li ◽  
Xiaosheng Fan ◽  
Ziyi Yan ◽  
Jia Zhan ◽  
Fangyun Cao ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Proliferation ◽  
Squamous Cell Carcinoma ◽  
Oral Squamous Cell Carcinoma ◽  
Cell Carcinoma ◽  
Cell Cycle Arrest ◽  
Squamous Cell ◽  
Cycle Arrest

Abstract Background The implication of circular RNAs (circRNAs) in human cancers has aroused much concern. In this study, we investigated the function of circ_0000745 and its potential functional mechanisms in oral squamous cell carcinoma (OSCC) to further understand OSCC pathogenesis. Methods The expression of circ_0000745, miR-488 and cyclin D1 (CCND1) mRNA was measured by quantitative real-time polymerase chain reaction (qPCR). Cell proliferation capacity was assessed by cell counting kit-8 (CCK-8) assay and colony formation assay. Cell cycle progression and cell apoptosis were determined by flow cytometry assay. The protein levels of CCND1, PCNA, Cleaved-caspase 3 and HuR were detected by western blot. Animal study was conducted to identify the role of circ_0000745 in vivo. The targeted relationship was verified by dual-luciferase reporter assay, pull-down assay or RNA immunoprecipitation (RIP) assay. Results The expression of circ_0000745 was increased in OSCC tissues and cells. Circ_0000745 downregulation inhibited OSCC cell proliferation and induced cell cycle arrest and apoptosis in vitro, as well as blocked tumor growth in vivo. MiR-488 was a target of circ_0000745, and circ_0000745 downregulation suppressed OSCC development by enriching miR-488. Besides, circ_0000745 regulated CCND1 expression by targeting miR-488. In addition, circ_0000745 regulated CCND1 expression by interacting with HuR protein. CCND1 knockdown also inhibited OSCC cell proliferation and induced cell cycle arrest and apoptosis in vitro, and CCND1 overexpression recovered the inhibitory effects on OSCC cell malignant behaviors caused by circ_0000745 downregulation. Conclusions Circ_0000745 regulated the expression of CCND1 partly by acting as miR-488 sponge and interacting with HuR protein, thus promoting the progression of OSCC.

scholarly journals Lenvatinib Inhibits Intrahepatic Cholangiocarcinoma Growth via Gadd45a-Mediated Cell Cycle Arrest

2021 ◽  
Author(s):  
Xia Yan ◽  
Dan Wang ◽  
Liping Zhuang ◽  
Peng Wang ◽  
Zhiqiang Meng ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Proliferation ◽  
Cell Cycle Arrest ◽  
Cell Lines ◽  
Intrahepatic Cholangiocarcinoma ◽  
Primary Liver Cancer ◽  
Transcriptional Profiling ◽  
Cycle Arrest

Abstract Background: Intrahepatic cholangiocarcinoma (ICC) is the second most common primary liver cancer, and its 5-year survival rate is less than 10%. Fibroblast growth factor receptor (FGFR) changes have been observed in 6%-50% of ICC patients, and patients with FGFR mutations have been shown to have more inert tumour biological activity than patients with wild-type FGFRs. Thus, as a pan-FGFR inhibitor, lenvatinib is supposed to play an anti-tumour role in ICC. However, no relevant experiments have been reported.Methods: Patients derived xenograft (PDX) model and cell line derived xenograft (CDX) model were both used for the in vivo study. For in vivo work, ICC cell lines were applied to analyse the effect of Lenvatinib on cell proliferation, cell cycle progression, apoptosis, and the molecular mechanism.Reaults: In the present study, we found that lenvatinib dramatically hindered in vivo tumor growth in ICC patient-derived xenograft models. In addition, by using in vitro experiments in ICC cell lines, we found that lenvatinib dose- and time-dependently inhibited the proliferation of ICC cells and induced cell cycle arrest in the G0/G1 phase. Transcriptional profiling analysis further applied indicated that lenvatinib might inhibit cell proliferation through the induction of cell-cycle arrestment via activating of Gadd45a, it was evidenced by that the knockout of Gadd45a significantly attenuated the cycle arrest induced by lenvatinib, as well as the inhibitory effect of lenvatinib on ICC.Conclusion: Our work firstly found that lenvatinib exerted excellent antitumor effect on ICC, mainly via inducing Gadd45a mediated cell cycle arrest. Our work provides evidence and a rationale for the future use of lenvatinib in the treatment of ICC.

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