MicroRNAs Contribute to Promyelocyte Apoptosis in As&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt;-Treated APL Cells

Background and Aims: We have previously shown that neuroglobin (Ngb) expression can be regulated by sodium arsenite (NaAsO₂) exposure in rat cerebellar granule neurons (CGNs). However, the precise molecular mechanisms of Ngb action are largely unknown. Ras homolog (Rho) guanosine triphosphatases (Rho GTPases) are involved in the regulation of a number of cellular processes, including cell cytotoxicity. It has been reported that Ngb can act as a guanine nucleotide dissociation inhibitior (GDI) role to inactivate Rho GTPases. Therefore, we investigated Rho GTPases activation induced by NaAsO₂ exposure in rat CGNs and effects of Rho GTPases activation on the cells. We also investigated the role of Ngb in this process. Methods: Primary cultures of CGNs were prepared from 7-day-old Wistar rat pups. The cytotoxic effects of NaAsO₂ on CGNs were evaluated using the Cell Counting Kit-8 assay and TUNEL staining. RNA interference technology was used to silence Ngb, and the subsequent effects were evaluated by quantitative RT-PCR and Western blot. Cdc42 and Rac1 activation were measured by pull-down assay and Western blot. Results: NaAsO₂ induced cytotoxicity in rat CGNs, increased GTP-bound form of Cdc42 and Rac1 GTPases in the cells. Furthermore, inhibition of Cdc42 or Rac1 activity using the inhibitor ZCL278 or NSC23766 decreased apoptosis and increased cell viability in the cells exposed to NaAsO₂. Using siRNA-mediated knockdown, we show that NaAsO₂-induced cytotoxicity was exacerbated, activation of Cdc42 (GTP-Cdc42) and Rac1 (GTP-Rac1) was increased in Ngb RNA silencing cells. Conclusions: cytotoxic effects of NaAsO₂ on rat CGNs is induced at least partly by Cdc42 and Rac1 activation, and Ngb can inhibit Cdc42 and Rac1 activation to play protective role in rat CGNs exposed to NaAsO₂.

Section: Liu Et Al: Protective Role Of Neuroglobin In Rat Cerebellarsupporting

confidence: 89%

Neuroglobin Plays a Protective Role in Arsenite-Induced Cytotoxicity by Inhibition of Cdc42 and Rac1GTPases in Rat Cerebellar Granule Neurons

Liu

Gao

An³

et al. 2015

“…The process of tumorigenesis is the result of a variety of complex factors, in which evasion of apoptosis is one of the crucial acquired capabilities used to promote cancer cell survival and proliferation [103][104][105][106]. However, the molecular bases of miR-100 involved in regulation of apoptosis in tumor cells remain uncharacterized.…”

Section: Mir-100 In Cancer Proliferation and Apoptosismentioning

confidence: 99%

Multiple Roles of MicroRNA-100 in Human Cancer and its Therapeutic Potential

Li¹,

Gao²,

Zhang³

et al. 2015

MicroRNAs (miRNAs) are a recently discovered class of endogenous, small (about 22 nucleotides) non-coding RNAs, which play important roles in cancer development and progression. Emerging evidence shows that microRNAs exert their regulatory effects by directly binding to the 3'- untranslated regions (UTRs) of their target genes. MicroRNA-100 (miR-100) is aberrantly expressed and functions in many human cancers by regulating multiple cell processes, such as cell cycle, proliferation, differentiation, migration, invasion and apoptosis, via post-transcriptionally regulating various target genes. A better understanding of the molecular mechanisms involved in miR-100-mediated tumor progression will provide an opportunity for exploring novel miR-100-based targeted therapies for human cancers. This review aims to summarize the recently published literature on the roles of miR-100 in regulating tumorigenesis, and explore its potential clinical applications for cancer diagnosis, prognosis and clinical treatment.

“…Although detected mainly in teenagers and adults, pediatric cases comprise a certain percentage of newly diagnosed AML patients [1]. The etiology and pathology of AML in children are not completely determined [2][3][4][5]. However, it is known that some AML in children with Down syndrome (DS) is characterized by a founding GATA1 mutation that cooperates with trisomy 21, followed by the acquisition of additional somatic mutations in epigenetic and kinase signaling genes [6][7][8].…”

Section: Introductionmentioning

confidence: 99%

Ginsenoside Rh2 Mitigates Pediatric Leukemia Through Suppression of Bcl-2 in Leukemia Cells

Wang

2015

Background/Aims: Acute myeloid leukemia (AML) is a severe malignant cancer worldwide, in both adult and pediatric patients. Since bone marrow cell transplantation is seriously limited by the availability of the immune-paired donor sources, the therapy for pediatric leukemia remains challenging. Ginsenoside Rh2 (GRh2) is a well-characterized component in red ginseng, and has established therapeutic effects for different diseases, although whether GRh2 may have a therapeutic effect on pediatric leukemia has not been investigated. Methods: We examined the effects of GRh2 on the survival of mice in an acute leukemia model. We analyzed the effects of GRh2 on the cell viability of leukemia cell lines in vitro, using a CCK-8 assay and an MTT assay. We analyzed the effects of GRh2 on the apoptosis of leukemia cell lines in vitro, by flow cytometry. We analyzed the levels of Bcl-2 and microRNA-21 (miR-21) in GRh2-treated leukemia cells. Prediction of binding between miR-21 and 3'-UTR of Bcl-2 mRNA was performed by a bioinformatics algorithm and confirmed by a dual luciferase reporter assay. Results: GRh2 significantly prolonged the survival of mice with pediatric leukemia. GRh2 significantly decreased the viability of leukemia cells in vitro, through induction of apoptosis. GRh2 significantly decreased the levels of an anti-apoptotic protein Bcl-2 in leukemia cells, possibly through induction of miR-21, which suppressed the translation of Bcl-2 mRNA via 3'-UTR binding. Conclusion: GRh2 may be an effective treatment for pediatric leukemia, and GRh2 may induce apoptosis of leukemia cells through miR-21-modulated suppression of Bcl-2.