Mechanistic insights into avian reovirus p17-modulated suppression of cell cycle CDK–cyclin complexes and enhancement of p53 and cyclin H interaction

Deng

Journal of Enzyme Inhibition and Medicinal Chemistry

et al. 2020

A novel series of cyclin-dependent kinases (CDKs) inhibitors, which play critical roles in the cell cycle control and regulation of cell transcription, were synthesised. A systematic study of enzymatic and cellular assays led to the identification of compound X22 with a nanomolar potency against CDK4 and CDK9 and potent antiproliferative activities against a panel of tumour cell lines. X22 could induce cell cycle arrest and cell apoptosis in cancer cell lines. X22 dose-dependently inhibits signalling pathways downstream of CDKs in cancer cells. In vivo antitumor activity assays, oral administration of X22 led to significant tumour regression in mouse model without obvious toxicity. Superior anti-cancer efficacy in vitro and in vivo of X22 demonstrated combined depletion of cell cycle and transcriptional CDK all contributed to antitumor activity. Taken together, concomitant inhibition of cell cycle and transcriptional CDK activities provided valuable guide for further structural optimisation.

Section: Resultssupporting

confidence: 93%

Novel CDKs inhibitors for the treatment of solid tumour by simultaneously regulating the cell cycle and transcription control

Deng

Journal of Enzyme Inhibition and Medicinal Chemistry

et al. 2020

“…The complexes then thread through the nuclear pore and transit to the cytoplasm in an hnRNP A1dependent manner. In this work, we uncovered a novel mechanism to elucidate hnRNP A1-and lamin A/C-modulated nucleocytoplasmic shuttling of p17, which is required for p17-mediated activation of p53 and inactivation of the Akt/mTORC1 pathway (27,28), cell cycle (29)(30)(31), autophagy (28,32), and cellular translation (27,33). A hypothesized GST pulldown assay.…”

Section: Discussionmentioning

confidence: 99%

“…A monopartite-type functional NLS near the C terminus of p17 is necessary for nuclear import (26) and interacts with nucleoporin Tpr localized within the nuclear basket of the NPC (27), which suppresses Tpr, thereby activating p53, PTEN, and p21 (27). Our team suggested that the avian reovirus (ARV) p17 protein performs specific duties in both the nucleus and the cytoplasm, as in mediating the Tpr/p53/PTEN/Akt/mTORC1 and mTORC2/Akt pathways (27,28), cell cycle (29)(30)(31), autophagy (28,32), and cellular translation (27,33). To date, the precise mechanisms of the involvement of cellular proteins in mediating nucleocytoplasmic shuttling of p17 remain unknown.…”

mentioning

confidence: 99%

Heterogeneous Nuclear Ribonucleoprotein A1 and Lamin A/C Modulate Nucleocytoplasmic Shuttling of Avian Reovirus p17

Chiu

Huang

et al. 2019

J Virol

Self Cite

Avian reovirus (ARV) p17 protein continuously shuttles between the nucleus and the cytoplasm via transcription-dependent and chromosome region maintenance 1 (CRM1)-independent mechanisms. Nevertheless, whether cellular proteins modulate nucleocytoplasmic shuttling of p17 remains unknown. This is the first report that heterogeneous nuclear ribonucleoprotein (hnRNP) A1 serves as a carrier protein to modulate nucleocytoplasmic shuttling of p17. Both in vitro and in vivo studies indicated that direct interaction of p17 with hnRNP A1 maps within the amino terminus (amino acids [aa] 19 to 40) of p17 and the Gly-rich region of the C terminus of hnRNP A1. Furthermore, our results reveal that the formation of p17-hnRNP A1-transportin 1 carrier-cargo complex is required to modulate p17 nuclear import. Utilizing sequence and mutagenesis analyses, we have identified nuclear export signal (NES) 19 LSLRELAI 26 of p17. Mutations of these residues causes a nuclear retention of p17. In this work, we uncovered that the N-terminal 21 amino acids (aa 19 to 40) of p17 that comprise the NES can modulate both p17 and hnRNP A1 interaction and nucleocytoplasmic shuttling of p17. In this work, the interaction site of p17 with lamin A/C was mapped within the amino terminus (aa 41 to 60) of p17 and p17 colocalized with lamin A/C at the nuclear envelope. Knockdown of hnRNP A1 or lamin A/C led to inhibition of nucleocytoplasmic shuttling of p17 and reduced virus yield. Collectively, the results of this study provide mechanistic insights into hnRNP A1 and lamin A/Cmodulated nucleocytoplasmic shuttling of the ARV p17 protein.IMPORTANCE Avian reoviruses (ARVs) cause considerable economic losses in the poultry industry. The ARV p17 protein continuously shuttles between the nucleus and the cytoplasm to regulate several cellular signaling pathways and interacts with several cellular proteins to cause translation shutoff, cell cycle arrest, and autophagosome formation, all of which enhance virus replication. To date the mechanisms underlying nucleocytoplasmic shuttling of p17 remain largely unknown. Here we report that hnRNP A1 and lamin A/C serve as carrier and mediator proteins to modulate nucleocytoplasmic shuttling of p17. The formation of p17-hnRNP A1-transportin 1 carrier-cargo complex is required to modulate p17 nuclear import. Furthermore, we have identified an NES-containing nucleocytoplasmic shuttling domain (aa 19 to 40) of p17 that is critical for binding to hnRNP A1 and for nucleocytoplasmic shuttling of p17. This study provides novel insights into how hnRNP A1 and lamin A/C modulate nucleocytoplasmic shuttling of the ARV p17 protein. RESULTSCellular proteins hnRNP A1 and lamin A/C coimmunoprecipatate with p17. As shown previously, we identified several cellular proteins, such as nucleoporin Tpr, vimentin, and lamin A/C, that interact with the ARV p17 protein (27,28,30). To explore whether and how cellular proteins are involved in mediating nucleocytoplasmic shut-Chiu et al. FIG 1 p17 interacts with hnRNP A1. (A) Identification of poten...

BioMed Research International

“…Cyclin B1 (CCNB1) and cyclin B2 (CCNB2) are important members of the cyclin family and are important cell cycle regulators related to G2/M detection sites [ 58 , 59 ]. One of its important roles is to modulate and form a complex with cyclin-dependent kinase 1 (CDK1) to phosphorylate the substrate, initiate the cell to G2/M phase from G1/S, and promote mitosis [ 60 ]. Checkpoint kinase 1 (CHEK1), as a DNA damage sensor and cell death pathway stimulator, regulates the progression of the cell cycle at the S phase, G2/M checkpoint [ 61 ].…”

Section: Discussionmentioning

confidence: 99%

Analysis of Transcription Factor-Related Regulatory Networks Based on Bioinformatics Analysis and Validation in Hepatocellular Carcinoma

Shui

Yao

Zhang

et al. 2018

Hepatocellular carcinoma (HCC) accounts for a significant proportion of liver cancer, which has become the second most common cause of cancer-related mortality worldwide. To investigate the potential mechanisms of invasion and progression of HCC, bioinformatics analysis and validation by qRT-PCR were performed. We found 237 differentially expressed genes (DEGs) including EGR1, FOS, and FOSB, which were three cancer-related transcription factors. Subsequently, we constructed TF-gene network and miRNA-TF-mRNA network based on data obtained from mRNA and miRNA expression profiles for analysis of HCC. We found that 42 key genes from the TF-gene network including EGR1, FOS, and FOSB were most enriched in the p53 signaling pathway. The qRT-PCR data confirmed that mRNA levels of EGR1, FOS, and FOSB all were decreased in HCC tissues. In addition, we confirmed that the mRNA levels of CCNB1, CCNB2, and CHEK1, three key markers of the p53 signaling pathway, were all increased in HCC tissues by bioinformatics analysis and qRT-PCR validation. Therefore, we speculated that miR-181a-5p, which was upregulated in HCC tissues, could regulate FOS and EGR1 to promote the invasion and progression of HCC by p53 signaling pathway. Overall, the study provides support for the possible mechanisms of progression in HCC.