scholarly journals p53 Stabilization and Accumulation Induced by Human Vaccinia-Related Kinase 1

2004 ◽  
Vol 24 (23) ◽  
pp. 10366-10380 ◽  
Author(s):  
Francisco M. Vega ◽  
Ana Sevilla ◽  
Pedro A. Lazo
Keyword(s):  
Small Interfering Rna ◽  
Protein A ◽  
Cellular Functions ◽  
Active Suppression ◽  
Tumor Susceptibility ◽  
Human Kinome ◽  
The Stability ◽  
Interfering Rna

ABSTRACT Variations in intracellular levels of p53 regulate many cellular functions and determine tumor susceptibility. Major mechanisms modulating p53 levels include phosphorylation and interaction of p53 with specific ubiquitin ligases that promote its degradation. N-terminal phosphorylation regulates the interaction of p53 with several regulatory molecules. Vaccinia-related kinase 1 (VRK1) is the prototype of a new Ser-Thr kinase family in the human kinome. VRK1 is located in the nucleus outside the nucleolus. Overexpression of VRK1 increases the stability of p53 by a posttranslational mechanism leading to its accumulation by a mechanism independent of the Chk2 kinase. Catalytically inactive VRK1 protein (a K179E mutant) does not induce p53 accumulation. VRK1 phosphorylates human p53 in Thr18 and disrupts p53-Mdm2 interaction in vitro, although a significant decrease in p53 ubiquitination by Mdm2 in vivo was not detected. VRK1 kinase does not phosphorylate Mdm2. VRK1-mediated p53 stabilization was also detected in Mdm2−/− cells. VRK1 also has an additive effect with MdmX or p300 to stabilize p53, and p300 coactivation and acetylation of p53 is enhanced by VRK1. The p53 stabilized by VRK1 is transcriptionally active. Suppression of VRK1 expression by specific small interfering RNA provokes several defects in proliferation, situating the protein in the regulation of this process. VRK1 might function as a switch controlling the proteins that interact with p53 and thus modifying its stability and activity. We propose VRK1 as the first step in a new pathway regulating p53 activity during cell proliferation.

scholarly journals Natural Polysaccharides for siRNA Delivery: Nanocarriers Based on Chitosan, Hyaluronic Acid, and Their Derivatives

Molecules ◽  
2019 ◽  
Vol 24 (14) ◽  
pp. 2570 ◽  
Author(s):  
Inés Serrano-Sevilla ◽  
Álvaro Artiga ◽  
Scott G. Mitchell ◽  
Laura De Matteis ◽  
Jesús M. de la Fuente
Keyword(s):  
Drug Delivery ◽  
Hyaluronic Acid ◽  
Small Interfering Rna ◽  
Drug Delivery Systems ◽  
Sirna Delivery ◽  
Delivery Systems ◽  
Low Toxicity ◽  
Interfering Rna

Natural polysaccharides are frequently used in the design of drug delivery systems due to their biocompatibility, biodegradability, and low toxicity. Moreover, they are diverse in structure, size, and charge, and their chemical functional groups can be easily modified to match the needs of the final application and mode of administration. This review focuses on polysaccharidic nanocarriers based on chitosan and hyaluronic acid for small interfering RNA (siRNA) delivery, which are highly positively and negatively charged, respectively. The key properties, strengths, and drawbacks of each polysaccharide are discussed. In addition, their use as efficient nanodelivery systems for gene silencing applications is put into context using the most recent examples from the literature. The latest advances in this field illustrate effectively how chitosan and hyaluronic acid can be modified or associated with other molecules in order to overcome their limitations to produce optimized siRNA delivery systems with promising in vitro and in vivo results.

scholarly journals Switching the intracellular pathway and enhancing the therapeutic efficacy of small interfering RNA by auroliposome

2020 ◽  
Vol 6 (30) ◽  
pp. eaba5379 ◽  
Author(s):  
Md. Nazir Hossen ◽  
Lin Wang ◽  
Harisha R. Chinthalapally ◽  
Joe D. Robertson ◽  
Kar-Ming Fung ◽  
...  
Keyword(s):  
Ovarian Cancer ◽  
Gold Nanoparticles ◽  
Gene Silencing ◽  
Small Interfering Rna ◽  
Sirna Delivery ◽  
Delivery Systems ◽  
Ovarian Cancer Cells ◽  
Interfering Rna

Gene silencing using small-interfering RNA (siRNA) is a viable therapeutic approach; however, the lack of effective delivery systems limits its clinical translation. Herein, we doped conventional siRNA-liposomal formulations with gold nanoparticles to create “auroliposomes,” which significantly enhanced gene silencing. We targeted MICU1, a novel glycolytic switch in ovarian cancer, and delivered MICU1-siRNA using three delivery systems—commercial transfection agents, conventional liposomes, and auroliposomes. Low-dose siRNA via transfection or conventional liposomes was ineffective for MICU1 silencing; however, in auroliposomes, the same dose gave >85% gene silencing. Efficacy was evident from both in vitro growth assays of ovarian cancer cells and in vivo tumor growth in human ovarian cell line—and patient-derived xenograft models. Incorporation of gold nanoparticles shifted intracellular uptake pathways such that liposomes avoided degradation within lysosomes. Auroliposomes were nontoxic to vital organs. Therefore, auroliposomes represent a novel siRNA delivery system with superior efficacy for multiple therapeutic applications.

scholarly journals Silencing of AURKA augments the antitumor efficacy of the AURKA inhibitor MLN8237 on neuroblastoma cells

2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Yan Yang ◽  
Lili Ding ◽  
Qi Zhou ◽  
Li Fen ◽  
Yuhua Cao ◽  
...  
Keyword(s):  
Small Interfering Rna ◽  
Neuroblastoma Cell ◽  
Neuroblastoma Cells ◽  
Inhibitory Effect ◽  
Neuroblastoma Cell Line ◽  
Inhibitory Effects ◽  
Rna Transfection ◽  
Interfering Rna

Abstract Background Aurora kinase A (AURKA) has been implicated in the regulation of cell cycle progression, mitosis and a key number of oncogenic signaling pathways in various malignancies including neuroblastoma. Small molecule inhibitors of AURKA have shown potential, but still not as good as expected effects in clinical trials. Little is known about this underlying mechanism. Here, we evaluated the inhibitory effects of AURKA inhibitor MLN8237 on neuroblastoma cells to understand the potential mechanisms responsible for tumor therapy. Methods MLN8237 treatment on neuroblastoma cell line IMR32 was done and in vivo inhibitory effects were investigated using tumor xenograft model. Cellular senescence was evaluated by senescence-associated β-gal Staining assay. Flow cytometry was used to tested cell cycle arrest and cell apoptosis. Senescence-associated signal pathways were detected by western blot. CD133 microbeads and microsphere formation were used to separate and enrich CD133+ cells. AURKA small interfering RNA transfection was carried to downregulate AURKA level. Finally, the combination of MLN8237 treatment with AURKA small interfering RNA transfection were adopted to evaluate the inhibitory effect on neuroblastoma cells. Results We demonstrate that MLN8237, an inhibitor of AURKA, induces the neuroblastoma cell line IMR32 into cellular senescence and G2/M cell phase arrest. Inactivation of AURKA results in MYCN destabilization and inhibits cell growth in vitro and in a mouse model. Although MLN8237 inhibits AURKA kinase activity, it has almost no inhibitory effect on the AURKA protein level. By contrast, MLN8237 treatment leads to abnormal high expression of AURKA in vitro and in vivo. Knockdown of AURKA reduces cell survival. The combination of MLN8237 with AURKA small interfering RNA results in more profound inhibitory effects on neuroblastoma cell growth. Moreover, MLN8237 treatment followed by AURKA siRNA forces senescent cells into apoptosis via suppression of the Akt/Stat3 pathway. Conclusions The effect of AURKA-targeted inhibition of tumor growth plays roles in both the inactivation of AURKA activity and the decrease in the AURKA protein expression level.

scholarly journals RhoGDIα-dependent balance between RhoA and RhoC is a key regulator of cancer cell tumorigenesis

2011 ◽  
Vol 22 (17) ◽  
pp. 3263-3275 ◽  
Author(s):  
T. T. Giang Ho ◽  
Audrey Stultiens ◽  
Johanne Dubail ◽  
Charles M. Lapière ◽  
Betty V. Nusgens ◽  
...  
Keyword(s):  
Tumor Growth ◽  
Cancer Progression ◽  
Dynamic Balance ◽  
Cellular Functions ◽  
Expression Of Genes ◽  
Genes Encoding ◽  
Interfering Rna

RhoGTPases are key signaling molecules regulating main cellular functions such as migration, proliferation, survival, and gene expression through interactions with various effectors. Within the RhoA-related subclass, RhoA and RhoC contribute to several steps of tumor growth, and the regulation of their expression affects cancer progression. Our aim is to investigate their respective contributions to the acquisition of an invasive phenotype by using models of reduced or forced expression. The silencing of RhoC, but not of RhoA, increased the expression of genes encoding tumor suppressors, such as nonsteroidal anti-inflammatory drug–activated gene 1 (NAG-1), and decreased migration and the anchorage-independent growth in vitro. In vivo, RhoC small interfering RNA (siRhoC) impaired tumor growth. Of interest, the simultaneous knockdown of RhoC and NAG-1 repressed most of the siRhoC-related effects, demonstrating the central role of NAG-1. In addition of being induced by RhoC silencing, NAG-1 was also largely up-regulated in cells overexpressing RhoA. The silencing of RhoGDP dissociation inhibitor α (RhoGDIα) and the overexpression of a RhoA mutant unable to bind RhoGDIα suggested that the effect of RhoC silencing is indirect and results from the up-regulation of the RhoA level through competition for RhoGDIα. This study demonstrates the dynamic balance inside the RhoGTPase network and illustrates its biological relevance in cancer progression.

An Amphiphilic Dendrimer for Effective Delivery of Small Interfering RNA and Gene Silencing In Vitro and In Vivo

2012 ◽  
Vol 51 (34) ◽  
pp. 8478-8484 ◽  
Author(s):  
Tianzhu Yu ◽  
Xiaoxuan Liu ◽  
Anne-Laure Bolcato-Bellemin ◽  
Yang Wang ◽  
Cheng Liu ◽  
...  
Keyword(s):  
Gene Silencing ◽  
Small Interfering Rna ◽  
Effective Delivery ◽  
Interfering Rna
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