Mislocalization of CDK11/PITSLRE, a regulator of the G2/M phase of the cell cycle, in Alzheimer disease

AbstractPost-mitotic neurons are typically terminally differentiated and in a quiescent status. However, in Alzheimer disease (AD), many neurons display ectopic re-expression of cell cycle-related proteins. Cyclin-dependent kinase 11 (CDK11) mRNA produces a 110-kDa protein (CDK11p110) throughout the cell cycle, a 58-kDa protein (CDK11p58) that is specifically translated from an internal ribosome entry site and expressed only in the G2/M phase of the cell cycle, and a 46-kDa protein (CDK11p46) that is considered to be apoptosis specific. CDK11 is required for sister chromatid cohesion and the completion of mitosis. In this study, we found that the expression patterns of CDK11 vary such that cytoplasmic CDK11 is increased in AD cellular processes, compared to a pronounced nuclear expression pattern in most controls. We also investigated the effect of amyloid precursor protein (APP) on CDK11 expression in vitro by using M17 cells overexpressing wild-type APP and APP Swedish mutant phenotype and found increased CDK11 expression compared to empty vector. In addition, amyloid-β25–35 resulted in increased CDK11 in M17 cells. These data suggest that CDK11 may play a vital role in cell cycle re-entry in AD neurons in an APP-dependent manner, thus presenting an intriguing novel function of the APP signaling pathway in AD.

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Effect of NS3 and NS5B proteins on classical swine fever virus internal ribosome entry site-mediated translation and its host cellular translation

Journal of General Virology ◽

10.1099/vir.0.83341-0 ◽

2008 ◽

Vol 89 (4) ◽

pp. 994-999 ◽

Cited By ~ 14

Author(s):

Ming Xiao ◽

Yan Bai ◽

Hui Xu ◽

Xiaolu Geng ◽

Jun Chen ◽

...

Keyword(s):

Internal Ribosome Entry Site ◽

Classical Swine Fever ◽

Rna Helicase ◽

Helicase Domain ◽

Dependent Manner ◽

Helicase Activity ◽

Entry Site ◽

Internal Ribosome Entry ◽

Cellular Translation

A full-length NS3 (NS3F) and a truncated NS3 protein (NS3H) with an RNA helicase domain possess RNA helicase activity. Using an in vitro system with a monocistronic reporter RNA or DNA, containing the CSFV 5′-UTR, we observed that both NS3F and NS3H enhanced internal ribosome entry site (IRES)-mediated and cellular translation in a dose-dependent manner, but NS3 protease (NS3P) that lacks a helicase domain did not. NS3F was stronger than NS3H in promoting both translations. These results showed that viral RNA helicase could promote viral and cellular translation, and higher RNA helicase activity might be more efficient. The NS5B protein, the viral replicase, did not significantly affect the IRES-directed or cellular translation alone. NS5B significantly enhanced the stimulative effect of NS3F on both IRES-mediated and cellular translation, but did not affect that of NS3H or NS3P. This suggests that NS5B and NS3 interact via the protease domain during the enhancement of translation.

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Cleavage of Poly(A)-Binding Protein by Poliovirus 3C Proteinase Inhibits Viral Internal Ribosome Entry Site-Mediated Translation

Journal of Virology ◽

10.1128/jvi.00006-08 ◽

2008 ◽

Vol 82 (19) ◽

pp. 9389-9399 ◽

Cited By ~ 40

Author(s):

Jennifer M. Bonderoff ◽

Jennifer L. LaRey ◽

Richard E. Lloyd

Keyword(s):

Internal Ribosome Entry Site ◽

Binding Protein ◽

Virus Protein ◽

Dependent Manner ◽

Entry Site ◽

Internal Ribosome Entry ◽

Initiation Factors ◽

Polypyrimidine Tract Binding Protein ◽

In Cells

ABSTRACT The two enteroviral proteinases, 2A proteinase (2Apro) and 3C proteinase (3Cpro), induce host cell translation shutoff in enterovirus-infected cells by cleaving canonical translation initiation factors. Cleavage of poly(A)-binding protein (PABP) by 3Cpro has been shown to be a necessary component for host translation shutoff. Here we show that 3Cpro inhibits cap-independent translation mediated by the poliovirus internal ribosome entry site (IRES) in a dose-dependent manner in HeLa translation extracts displaying cap-poly(A) synergy. This effect is independent of the stimulatory effect of 2Apro on IRES translation, and 3Cpro-induced translation inhibition can be partially rescued by addition of recombinant PABP in vitro. 3Cpro inhibits IRES translation on transcripts containing or lacking poly(A) tails, suggesting that cleavage of PABP and IRES trans-activating factors polypyrimidine tract-binding protein and poly r(C)-binding protein 2 may also be important for inhibition. Expression of 3Cpro cleavage-resistant PABP in cells increased translation of nonreplicating viral minigenome reporter RNAs during infection and also delayed and reduced virus protein synthesis from replicating RNA. Further, expression of cleavage-resistant PABP in cells reduced the accumulation of viral RNA and the output of infectious virus. These results suggest that cleavage of PABP contributes to viral translation shutoff that is required for the switch from translation to RNA replication.

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SCFFbxw5 targets MCAK in G2/M to facilitate ciliogenesis in the following cell cycle

10.1101/2021.01.15.426831 ◽

2021 ◽

Author(s):

Jörg Schweiggert ◽

Gregor Habeck ◽

Sandra Hess ◽

Felix Mikus ◽

Klaus Meese ◽

...

Keyword(s):

Cell Cycle ◽

Primary Cilia ◽

Protein Microarrays ◽

Mitotic Progression ◽

Cellular Processes ◽

Ubiquitin E3 Ligase ◽

M Phase ◽

Cancer Types ◽

In Cells

AbstractThe microtubule depolymerase Kif2C/MCAK plays important roles in various cellular processes and is frequently overexpressed in different cancer types. Despite the importance of its correct abundance, remarkably little is known about how MCAK levels are regulated in cells.Using comprehensive screening on protein microarrays, we identified 161 candidate substrates of the multi-subunit ubiquitin E3 ligase SCFFbxw5, including MCAK. In vitro reconstitution assays demonstrate that MCAK and its closely related orthologs Kif2A and Kif2B become efficiently polyubiquitylated by neddylated SCFFbxw5 and Cdc34, without requiring preceding modifications. In cells, SCFFbxw5 targets MCAK for proteasomal degradation specifically during G2/M. While this seems largely dispensable for mitotic progression, loss of Fbxw5 leads to increased MCAK levels at basal bodies, which impair formation of primary cilia in the following G1. We have thus identified a novel regulatory event of ciliogenesis that occurs already within the G2/M phase of the preceding cell cycle.

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Purified Vitexin Compound 1 Serves as a Promising Antineoplastic Agent in Ovarian Cancer

Frontiers in Oncology ◽

10.3389/fonc.2021.734708 ◽

2021 ◽

Vol 11 ◽

Author(s):

Kewen Ma ◽

Kuansong Wang ◽

Yingjun Zhou ◽

Nian Liu ◽

Wei Guo ◽

...

Keyword(s):

Cell Cycle ◽

Ovarian Cancer ◽

Cancer Cells ◽

Antineoplastic Agent ◽

Chinese Herb ◽

Ovarian Cancer Cells ◽

Therapeutic Effects ◽

Dependent Manner ◽

M Phase

Ovarian cancer is a common gynecologic aggressive neoplasm. The mortality of ovarian cancer is top among gynecologic malignancies due to the insidious onset, atypical early symptoms, and chemoresistance. Therefore, it is urgent to seek another promising treatment for ovarian cancer. Purified vitexin compound 1 (VB1) is a kind of neolignan from the seed of traditional Chinese herb vitex negundo that possessed diverse pharmacological effects. VB1 can exhibit anti-neoplastic activities against various cancers. However, the role of VB1 in ovarian cancer treatment has not been elaborated, and the mechanism is unknown. The aim of this study was to investigate the therapeutic effects of VB1 in ovarian cancer cells both in vitro and in vivo, along with the molecular mechanism of action. In vitro, VB-1 can effectively suppress the proliferation, induce apoptosis, and block cell cycle at G2/M phase with a concentration dependent manner in ovarian cancer cells. Western blot assay showed that VB1 induce apoptosis via upregulating expression of cleaved-caspase3 and block cell cycle at G2/M phase through upregulating expression of P21. Meanwhile, VB1 can effectively inhibit tumor growth in xenograft mouse model. Our research indicated that VB1 can significantly exert its anti-neoplastic effects and may represent a new class of agents in ovarian cancer therapy.

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Resurrection of a Viral Internal Ribosome Entry Site from a 700 Year Old Ancient Northwest Territories Cripavirus

Viruses ◽

10.3390/v13030493 ◽

2021 ◽

Vol 13 (3) ◽

pp. 493

Author(s):

Xinying Wang ◽

Marli Vlok ◽

Stephane Flibotte ◽

Eric Jan

Keyword(s):

Northwest Territories ◽

Internal Ribosome Entry Site ◽

Infectious Clone ◽

Dependent Manner ◽

Binding Assays ◽

Entry Site ◽

Internal Ribosome Entry ◽

Conserved Core ◽

Partial Fragment

The dicistrovirus intergenic region internal ribosome entry site (IGR IRES) uses an unprecedented, streamlined mechanism whereby the IRES adopts a triple-pseudoknot (PK) structure to directly bind to the conserved core of the ribosome and drive translation from a non-AUG codon. The origin of this IRES mechanism is not known. Previously, a partial fragment of a divergent dicistrovirus RNA genome, named ancient Northwest territories cripavirus (aNCV), was extracted from 700-year-old caribou feces trapped in a subarctic ice patch. The aNCV IGR sequence adopts a secondary structure similar to contemporary IGR IRES structures, however, there are subtle differences including 105 nucleotides upstream of the IRES of unknown function. Using filter binding assays, we showed that the aNCV IRES could bind to purified ribosomes, and toeprinting analysis pinpointed the start site at a GCU alanine codon adjacent to PKI. Using a bicistronic reporter RNA, the aNCV IGR can direct translation in vitro in a PKI-dependent manner. Lastly, a chimeric infectious clone swapping in the aNCV IRES supported translation and virus infection. The characterization and resurrection of a functional IGR IRES from a divergent 700-year-old virus provides a historical framework for the importance of this viral translational mechanism.

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Tryprostatin A, a specific and novel inhibitor of microtubule assembly

Biochemical Journal ◽

10.1042/bj3330543 ◽

1998 ◽

Vol 333 (3) ◽

pp. 543-548 ◽

Cited By ~ 152

Author(s):

Takeo USUI ◽

Masuo KONDOH ◽

Cheng-Bin CUI ◽

Tadanori MAYUMI ◽

Hiroyuki OSADA

Keyword(s):

Cell Cycle ◽

Cell Growth ◽

Cell Cycle Progression ◽

Microtubule Assembly ◽

Inhibition Mechanism ◽

Dependent Manner ◽

Cycle Progression ◽

Terminal Domain ◽

M Phase

We have investigated the cell cycle inhibition mechanism and primary target of tryprostatin A (TPS-A) purified from Aspergillus fumigatus. TPS-A inhibited cell cycle progression of asynchronously cultured 3Y1 cells in the M phase in a dose- and time-dependent manner. In contrast, TPS-B (the demethoxy analogue of TPS-A) showed cell-cycle non-specific inhibition on cell growth even though it inhibited cell growth at lower concentrations than TPS-A. TPS-A treatment induced the reversible disruption of the cytoplasmic microtubules of 3Y1 cells as observed by indirect immunofluorescence microscopy in the range of concentrations that specifically inhibited M-phase progression. TPS-A inhibited the assembly in vitro of microtubules purified from bovine brains (40% inhibition at 250 µM); however, there was little or no effect on the self-assembly of purified tubulin when polymerization was induced by glutamate even at 250 µM TPS-A. TPS-A did not inhibit assembly promoted by taxol or by digestion of the C-terminal domain of tubulin. However, TPS-A blocked the tubulin assembly induced by inducers interacting with the C-terminal domain, microtubule-associated protein 2 (MAP2), tau and poly-(l-lysine). These results indicate that TPS-A is a novel inhibitor of MAP-dependent microtubule assembly and, through the disruption of the microtubule spindle, specifically inhibits cell cycle progression at the M phase.

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Aqueous Extract of Shi-Liu-Wei-Liu-Qi-Yin Induces G2/M Phase Arrest and Apoptosis in Human Bladder Carcinoma Cells via Fas and Mitochondrial Pathway

Evidence-based Complementary and Alternative Medicine ◽

10.1093/ecam/nep016 ◽

2011 ◽

Vol 2011 ◽

pp. 1-10 ◽

Cited By ~ 3

Author(s):

Ting-Tsz Ou ◽

Chau-Jong Wang ◽

Guang-Uei Hung ◽

Cheng-Hsun Wu ◽

Huei-Jane Lee

Keyword(s):

Cell Cycle ◽

Bladder Carcinoma ◽

Tumor Model ◽

Cyclin B1 ◽

Mitochondrial Pathway ◽

Dependent Manner ◽

Human Bladder ◽

Phase Arrest ◽

M Phase

Shi-Liu-Wei-Liu-Qi-Yin (SLWLQY) was traditionally used to treat cancers. However, scientific evidence of the anticancer effects still remains undefined. In this study, we aimed to clarify the possible mechanisms of SLWLQY in treating cancer. We evaluated the effects of SLWLQY on apoptosis-related experiments inducing in TSGH-8301 cells by (i) 3-(4,5-dimethylthiazol-zyl)-2,5-diphenylterazolium bromide (MTT) for cytotoxicity; (ii) cell-cycle analysis and (iii) western blot analysis of the G2/M-phase and apoptosis regulatory proteins. Human bladder carcinoma TSGH-8301 cells were transplanted into BALB/c nude mice as a tumor model for evaluating the antitumor effect of SLWLQY. Treatment of SLWLQY resulted in the G2/M phase arrest and apoptotic death in a dose-dependent manner, accompanied by a decrease in cyclin-dependent kinases (cdc2) and cyclins (cyclin B1). SLWLQY stimulated increases in the protein expression of Fas and FasL, and induced the cleavage of caspase-3, caspase-9 and caspase-8. The ratio of Bax/Bcl2was increased by SLWLQY treatment. SLWLQY markedly reduced tumor size in TSGH-8301 cells-xenografted tumor tissues. In the tissue specimen, SLWLQY up-regulated the expression of Fas, FasL and Bax proteins, and down-regulated Bcl2as well as inin vitroassay. Our results showed that SLWLQY reduced tumor growth, caused cell-cycle arrest and apoptosis in TSGH-8301 cells via the Fas and mitochondrial pathway.

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In vivo footprint of a picornavirus internal ribosome entry site reveals differences in accessibility to specific RNA structural elements

Journal of General Virology ◽

10.1099/vir.0.83218-0 ◽

2007 ◽

Vol 88 (11) ◽

pp. 3053-3062 ◽

Cited By ~ 17

Author(s):

Olga Fernández-Miragall ◽

Encarnación Martínez-Salas

Keyword(s):

Internal Ribosome Entry Site ◽

Living Cells ◽

Dependent Manner ◽

Entry Site ◽

Internal Ribosome Entry ◽

Essential Information ◽

Mouth Disease Virus ◽

Ires Element

Internal ribosome entry site (IRES) elements were described in picornaviruses as an essential region of the viral RNA. Understanding of IRES function requires a detailed knowledge of each step involved in the internal initiation process, from RNA folding and IRES–protein interaction to ribosome recruitment. Thus, deciphering IRES accessibility to external agents due to RNA structural features, as well as RNA–protein protection within living cells, is of primary importance. In this study, two chemical reagents, dimethylsulfate (DMS) and aminomethylpsoralen, have been used to footprint the entire IRES of foot-and-mouth disease virus (FMDV) in living cells; these reagents enter the cell membrane and interact with nucleic acids in a structure-dependent manner. For FMDV, as in other picornaviruses, viral infection is dependent on the correct function of the IRES; therefore, the IRES region itself constitutes a useful target of antiviral drugs. Here, the in vivo footprint of a picornavirus IRES element in the context of a biologically active mRNA is shown for the first time. The accessibility of unpaired adenosine and cytosine nucleotides in the entire FMDV IRES was first obtained in vitro by DMS probing; subsequently, this information was used to interpret the footprint data obtained in vivo for the mRNA encompassing the IRES element in the intercistronic space. The results of DMS accessibility and UV–psoralen cross-linking studies in the competitive cellular environment provided evidence for differences in RNA structure from data obtained in vitro, and provided essential information to identify appropriate targets within the FMDV IRES aimed at combating this important pathogen.

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The Olive Leaves Extract Has Anti-Tumor Effects against Neuroblastoma through Inhibition of Cell Proliferation and Induction of Apoptosis

Nutrients ◽

10.3390/nu13072178 ◽

2021 ◽

Vol 13 (7) ◽

pp. 2178

Author(s):

Fabio Morandi ◽

Veronica Bensa ◽

Enzo Calarco ◽

Fabio Pastorino ◽

Patrizia Perri ◽

...

Keyword(s):

Cell Cycle ◽

Cell Proliferation ◽

Cell Viability ◽

Cell Cycle Progression ◽

Treatment Strategies ◽

Annexin V ◽

Dependent Manner ◽

Induction Of Apoptosis ◽

Dose Dependent

Neuroblastoma (NB) is the most common extra-cranial solid tumor of pediatric age. The prognosis for high-risk NB patients remains poor, and new treatment strategies are desirable. The olive leaf extract (OLE) is constituted by phenolic compounds, whose health beneficial effects were reported. Here, the anti-tumor effects of OLE were investigated in vitro on a panel of NB cell lines in terms of (i) reduction of cell viability; (ii) inhibition of cell proliferation through cell cycle arrest; (iii) induction of apoptosis; and (iv) inhibition of cell migration. Furthermore, cytotoxicity experiments, by combining OLE with the chemotherapeutic topotecan, were also performed. OLE reduced the cell viability of NB cells in a time- and dose-dependent manner in 2D and 3D models. NB cells exposed to OLE underwent inhibition of cell proliferation, which was characterized by an arrest of the cell cycle progression in G0/G1 phase and by the accumulation of cells in the sub-G0 phase, which is peculiar of apoptotic death. This was confirmed by a dose-dependent increase of Annexin V+ cells (peculiar of apoptosis) and upregulation of caspases 3 and 7 protein levels. Moreover, OLE inhibited the migration of NB cells. Finally, the anti-tumor efficacy of the chemotherapeutic topotecan, in terms of cell viability reduction, was greatly enhanced by its combination with OLE. In conclusion, OLE has anti-tumor activity against NB by inhibiting cell proliferation and migration and by inducing apoptosis.

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