scholarly journals Protein kinase D1 phosphorylates CBX8 to facilitate the disassociation of PRC1 complex from p16 promoter and promotes cell senescence

2020 ◽  
Author(s):  
Yuanyuan Su ◽  
Yao Liang ◽  
Chenzhong Xu ◽  
Na Zhang ◽  
Doudou Liu ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Protein Kinase ◽  
Cell Biology ◽  
Hepatocellular Cancer ◽  
Cell Senescence ◽  
Polycomb Group ◽  
Republic Of China ◽  
Protein Kinase D1 ◽  
Serum Stimulation ◽  
And Migration

AbstractThe Polycomb group (PcG) protein chromobox 8 (CBX8) is the subunit of Polycomb repressive complex 1 (PRC1) and recognizes the trimethylation of histone H3 on Lysine 27 (H3K27me3), and coordinates with PRC2 complex to function as epigenetic gene silencer. CBX8 plays a key role in cell proliferation, stem cell biology, cell senescence, and cancer development. However, our knowledge of CBX8 post-translational modifications remains elusive. Here, we report that protein kinase D1 (PKD1) interacts and phosphorylates CBX8 at Ser256 and Ser311 in an evolutionarily conserved motif. We found that PKD1 activation triggered by serum stimulation, Nocodazole treatment and oncogene Ras-induced cell senescence (Ras OIS) all promotes CBX8 S256/311 phosphorylation. PKD1-mediated CBX8 S256/311 phosphorylation impairs PRC1 complex integrity by reducing the binding of CBX8 to other PRC1 components BMI1 and RING1B, decreases the monoubiquitination of histone H2AK119, and results in CBX8 dissociation from its target INK4a/ARF locus and the de-repression of p16, and thus ultimately facilitates cellular senescence. CBX8 S256/311 phosphorylation also compromises hepatocellular cancer cells proliferation and migration. Collectively, these results suggest that PKD1-mediated CBX8 S256/311 phosphorylation is a key mechanism governing CBX8 function, including cell senescence and cancer cell proliferation.Financial supportThis work was supported by grants from Ministry of Science and Technology of the People’s Republic of China (2018YFC2000102), and from National Natural Science Foundation of China (31871382 and 81571369).

ARFGAP3 an androgen target gene promotes prostate cancer cell proliferation and migration.

2020 ◽  
Author(s):  
Lungwani Muungo
Keyword(s):  
Cell Proliferation ◽  
Cancer Cell ◽  
Cell Biology ◽  
Adaptor Protein ◽  
Cancer Cell Proliferation ◽  
Lncap Cells ◽  
Gtpase Activating Protein ◽  
Cell Proliferation And Migration ◽  
And Migration ◽  
Proliferation And Migration

ADP ribosylation factor GTPase-activating protein 3 (ARFGAP3) is a GTPase-activating protein that associates with the Golgiapparatus and regulates the vesicular trafficking pathway. In the present study, we examined the contribution of ARFGAP3 toprostate cancer cell biology. We showed that ARFGAP3 expression was induced by 100 nM of dihydrotestosterone (DHT) atboth the mRNA and protein levels in androgen-sensitive LNCaP cells. We generated stable transfectants of LNCaP cells withFLAG-tagged ARFGAP3 or a control empty vector and showed that ARFGAP3 overexpression promoted cell proliferation andmigration compared with control cells. We found that ARFGAP3 interacted with paxillin, a focal adhesion adaptor protein thatis important for cell mobility and migration. Small interfering RNA (siRNA)-mediated knockdown of ARFGAP3 showed thatARFGAP3 siRNA markedly reduced LNCaP cell growth. Androgen receptor (AR)-dependent transactivation activity on prostatespecificantigen (PSA) enhancer was synergistically promoted by exogenous ARFGAP3 and paxillin expression, as shown byluciferase assay in LNCaP cells. Thus, our results suggest that ARFGAP3 is a novel androgen-regulated gene that can promoteprostate cancer cell proliferation and migration in collaboration with paxillin.

scholarly journals Protein kinase D1 phosphorylation of KAT7 enhances its protein stability and promotes replication licensing and cell proliferation

2020 ◽  
Vol 6 (1) ◽  
Author(s):  
Yao Liang ◽  
Yuanyuan Su ◽  
Chenzhong Xu ◽  
Na Zhang ◽  
Doudou Liu ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Dna Replication ◽  
Protein Kinase ◽  
Histone H4 ◽  
Replication Complex ◽  
Protein Kinase D1 ◽  
Defective Mutant ◽  
Histone H4 Acetylation

Abstract The histone acetyltransferase (HAT) KAT7/HBO1/MYST2 plays a crucial role in the pre-replication complex (pre-RC) formation, DNA replication and cell proliferation via acetylation of histone H4 and H3. In a search for protein kinase D1 (PKD1)-interacting proteins, we have identified KAT7 as a potential PKD1 substrate. We show that PKD1 directly interacts and phosphorylates KAT7 at Thr97 and Thr331 in vitro and in vivo. PKD1-mediated phosphorylation of KAT7 enhances its expression levels and stability by reducing its ubiquitination-mediated degradation. Significantly, the phospho-defective mutant KAT7-Thr97/331A attenuates histone H4 acetylation levels, MCM2/6 loading on the chromatin, DNA replication and cell proliferation. Similarly, PKD1 knockdown decreases, whereas the constitutive active mutant PKD1-CA increases histone H4 acetylation levels and MCM2/6 loading on the chromatin. Overall, these results suggest that PKD1-mediated phosphorylation of KAT7 may be required for pre-RC formation and DNA replication.

The PKC- Inhibitor Enzastaurin Inhibits MM Cell Growth, Survival and Migration in the Bone Marrow Microenvironment.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 1584-1584 ◽  
Author(s):  
Klaus Podar ◽  
Marc S. Raab ◽  
Dean Abtahi ◽  
Yu-Tzu Tai ◽  
Boris Lin ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Protein Kinase C ◽  
Cell Migration ◽  
Protein Kinase ◽  
Cell Growth ◽  
Cell Lines ◽  
Pkc Inhibitor ◽  
Kinase C ◽  
Pkc Signaling ◽  
And Migration

Abstract Members of the protein kinase C (PKC) family of serine- threonine protein kinases mediate multiple physiological functions including differentiation, growth and survival, invasiveness, angiogenesis and drug efflux. Dysregulation of PKC signaling has been implicated in tumor progression and prompted the development of novel anticancer therapeutics. In multiple myeloma (MM) PKC isoforms are: (1) involved in MM cell apoptosis; (2) associated with VEGF- and Wnt- induced MM cell migration; and (3) controlling shedding of IL-6 receptor alpha. However, to date the potential of targeting PKC signaling sequelae in MM has not been evaluated. Here we investigated the novel orally available protein- kinase C (PKC) inhibitor Enzastaurin (Eli Lilly and Company) for its therapeutic efficacy in MM. We first tested the ability of Enzastaurin to suppress MM cell proliferation in a wide array of MM cell lines. Our data show that Enzastaurin inhibits 3H[dT] uptake in all cell lines tested in a low micromolar range equivalent to the concentration range achieved in the patient plasma during clinical trials. Importantly, Enzastaurin also abrogates MM cell proliferation in a BMSC-MM coculture system. We next sought to determine whether Enzastaurin can inhibit cell survival and found dose- dependent induction of MM cell apoptosis in MM cell lines MM.1S, MM.1R, OPM-1, OPM-2, RPMI-8226, and RPMI-dox40. Moreover, Enzastaurin significantly inhibited VEGF- induced MM cell migration on fibronectin. Importantly, IGF-1- induced MM cell migration was abrogated by Enzastaurin, demonstrating the requirement of PKC. Signaling pathways mediating these effects were next examined: Our data show that Enzastaurin abrogates phosphorylation of Akt and GSK3beta, which is required for MM cell growth and migration. Furthermore, ongoing studies are evaluating the efficacy of Enzastaurin in a murine model of human MM. Taken together, these studies show for the first time the preclinical efficacy of the orally available PKC inhibitor Enzastaurin providing the basis for its clinical evaluation to improve patient outcome in MM.

GW654652, the pan-inhibitor of VEGF receptors, blocks the growth and migration of multiple myeloma cells in the bone marrow microenvironment

Blood ◽  
2004 ◽  
Vol 103 (9) ◽  
pp. 3474-3479 ◽  
Author(s):  
Klaus Podar ◽  
Laurence P. Catley ◽  
Yu-Tzu Tai ◽  
Reshma Shringarpure ◽  
Pedro Carvalho ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Bone Marrow ◽  
Cell Proliferation ◽  
Protein Kinase ◽  
Tyrosine Kinase ◽  
Bone Marrow Microenvironment ◽  
Vegf Receptor ◽  
Vegf Receptors ◽  
And Migration ◽  
Dependent Pathway

Abstract Previous studies have shown that the multiple myeloma (MM) cell line and MM patient cells express high-affinity vascular endothelial growth factor (VEGF) receptor-1 or Fms-like tyrosine kinase-1 (Flt-1) but not VEGF receptor-2 or Flk-1/kinase insert domain-containing receptor (Flk-1/KDR) and that VEGF triggers MM cell proliferation through a mitogen-activated protein kinase (MAPK)-dependent pathway and migration through a protein kinase C (PKC)-dependent pathway. The present study evaluates the efficacy of the small molecule tyrosine-kinase inhibitor GW654652, which inhibits all 3 VEGF receptors with similar potency. We show that GW654652 acts directly on MM cells and in the bone marrow microenvironment. Specifically, GW654652 (1-10 μg/mL) inhibits, in a dose-dependent fashion, VEGF-triggered migrational activity and cell proliferation of MM cell lines that are sensitive and resistant to conventional therapy. As expected from our previous studies of VEGF-induced signaling and sequelae in MM cells, GW654652 blocked VEGF-induced Flt-1 phosphorylation and downstream activation of AKT-1 and MAPK-signaling cascades. Importantly, GW654652 also inhibits interleukin-6 and VEGF secretion and proliferation of MM cells induced by tumor cell binding to bone marrow (BM) stromal cells. The activity of a pan-VEGF receptor inhibitor against MM cells in the BM milieu, coupled with its lack of major toxicity in preclinical mouse models, provides the framework for clinical trials of this drug class to improve patient outcome in MM. (Blood. 2004;103:3474-3479)

scholarly journals FAK Inhibition Induces Glioblastoma Cell Senescence-Like State through p62 and p27

Cancers ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1086 ◽  
Author(s):  
Lía Alza ◽  
Mireia Nàger ◽  
Anna Visa ◽  
Carles Cantí ◽  
Judit Herreros
Keyword(s):  
Cell Proliferation ◽  
Poor Prognosis ◽  
Focal Adhesions ◽  
Cell Senescence ◽  
Central Component ◽  
Cancer Cell Proliferation ◽  
Cell Proliferation And Migration ◽  
Therapeutic Value ◽  
And Migration ◽  
Proliferation And Migration

Focal adhesion kinase (FAK) is a central component of focal adhesions that regulate cancer cell proliferation and migration. Here, we studied the effects of FAK inhibition in glioblastoma (GBM), a fast growing brain tumor that has a poor prognosis. Treating GBM cells with the FAK inhibitor PF-573228 induced a proliferative arrest and increased cell size. PF-573228 also reduced the growth of GBM neurospheres. These effects were associated with increased p27/CDKN1B levels and β-galactosidase activity, compatible with acquisition of senescence. Interestingly, FAK inhibition repressed the expression of the autophagy cargo receptor p62/SQSTM-1. Moreover, depleting p62 in GBM cells also induced a senescent-like phenotype through transcriptional upregulation of p27. Our results indicate that FAK inhibition arrests GBM cell proliferation, resulting in cell senescence, and pinpoint p62 as being key to this process. These findings highlight the possible therapeutic value of targeting FAK in GBM.

scholarly journals 751 Transgenic Protein Kinase D1 Stimulates the Rate of Epithelial Cell Proliferation in Intestinal Crypts

2010 ◽  
Vol 138 (5) ◽  
pp. S-103
Author(s):  
James Sinnett-Smith ◽  
Robert K. Kui ◽  
Steven H. Young ◽  
Carlos Huang ◽  
Nora Rozengurt ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Protein Kinase ◽  
Epithelial Cell ◽  
Epithelial Cell Proliferation ◽  
Protein Kinase D1 ◽  
Transgenic Protein
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