Protein kinase C involvement in cell cycle modulation

2014 ◽  
Vol 42 (5) ◽  
pp. 1471-1476 ◽  
Author(s):  
Alessandro Poli ◽  
Sara Mongiorgi ◽  
Lucio Cocco ◽  
Matilde Y. Follo

Protein kinases C (PKCs) are a family of serine/threonine kinases which act as key regulators in cell cycle progression and differentiation. Studies of the involvement of PKCs in cell proliferation showed that their role is dependent on cell models, cell cycle phases, timing of activation and localization. Indeed, PKCs can positively and negatively act on it, regulating entry, progression and exit from the cell cycle. In particular, the targets of PKCs resulted to be some of the key proteins involved in the cell cycle including cyclins, cyclin-dependent kinases (Cdks), Cip/Kip inhibitors and lamins. Several findings described roles for PKCs in the regulation of G1/S and G2/M checkpoints. As a matter of fact, data from independent laboratories demonstrated PKC-related modulations of cyclins D, leading to effects on the G1/S transition and differentiation of different cell lines. Moreover, interesting data were published on PKC-mediated phosphorylation of lamins. In addition, PKC isoenzymes can accumulate in the nuclei, attracted by different stimuli including diacylglycerol (DAG) fluctuations during cell cycle progression, and target lamins, leading to their disassembly at mitosis. In the present paper, we briefly review how PKCs could regulate cell proliferation and differentiation affecting different molecules related to cell cycle progression.

2003 ◽  
Vol 228 (5) ◽  
pp. 590-595 ◽  
Author(s):  
Aliye Uc ◽  
Bradley E. Britigan

Intestinal epithelium undergoes a rapid self-renewal process characterized by the proliferation of the crypt cells, their differentiation into mature enterocytes as they migrate up to the villi, followed by their shedding as they become senescent villus enterocytes. The exact mechanism that regulates the intestinal epithelium renewal process is not well understood, but the differential expression of regulatory genes along the crypt-villus axis may have a role. Heme oxygenase-1 (HO-1) is involved in endothelial cell cycle progression, but its role in the intestinal epithelial cell turnover has not been explored. With its effects on cell proliferation and its differential expression along the crypt-villus axis, HO-1 may play a role in the intestinal epithelial cell renewal process. In this study, we examined the role of HO-1 in the proliferation and differentiation of Caco-2 cells, a well-established in vitro model for human enterocytes. After confluence, Caco-2 cells undergo spontaneous differentiation and mimic the crypt to villus maturation observed in vivo. In preconfluent and confluent Caco-2 cells, HO-1 protein expression was determined with the immunoblot. HO-1 activity was determined by the ability of the enzyme to generate bilirubin from hemin. The effect of a HO-1 enzyme activity inhibitor, tin protoporphyrin (SnPP), on Caco-2 cell proliferation and differentiation was examined. In preconfluent cells, cell number was determined periodically as a marker of proliferation. Cell viability was measured with MTT assay. Cell differentiation was assessed by the expression of a brush border enzyme, alkaline phophatase (ALP). HO-1 was expressed in subconfluent Caco-2 cells and remained detectable until 2 days postconfluency. This timing was consistent with cells starting their differentiation and taking the features of normal intestinal epithelial cells. HO-1 was inducible in confluent Caco-2 cells by the enzyme substrate, hemin in a dose- and time-dependent manner. SnPP decreased the cell number and viability of preconfluent cells and delayed the ALP enzyme activity of confluent cells. HO-1 may be involved in intestinal cell cycle progression.


2018 ◽  
Vol 46 (5) ◽  
pp. 1083-1091 ◽  
Author(s):  
Laura J.A. Hardwick ◽  
Roberta Azzarelli ◽  
Anna Philpott

Embryogenesis requires an exquisite regulation of cell proliferation, cell cycle withdrawal and differentiation into a massively diverse range of cells at the correct time and place. Stem cells also remain to varying extents in different adult tissues, acting in tissue homeostasis and repair. Therefore, regulated proliferation and subsequent differentiation of stem and progenitor cells remains pivotal throughout life. Recent advances have characterised the cell cycle dynamics, epigenetics, transcriptome and proteome accompanying the transition from proliferation to differentiation, revealing multiple bidirectional interactions between the cell cycle machinery and factors driving differentiation. Here, we focus on a direct mechanistic link involving phosphorylation of differentiation-associated transcription factors by cell cycle-associated Cyclin-dependent kinases. We discuss examples from the three embryonic germ layers to illustrate this regulatory mechanism that co-ordinates the balance between cell proliferation and differentiation.


2001 ◽  
Vol 114 (14) ◽  
pp. 2553-2560 ◽  
Author(s):  
Martin Alexander Schwartz ◽  
Richard K. Assoian

Cell cycle progression in mammalian cells is strictly regulated by both integrin-mediated adhesion to the extracellular matrix and by binding of growth factors to their receptors. This regulation is mediated by G1 phase cyclin-dependent kinases (CDKs), which are downstream of signaling pathways under the integrated control of both integrins and growth factor receptors. Recent advances demonstrate a surprisingly diverse array of integrin-dependent signals that are channeled into the regulation of the G1 phase CDKs. Regulation of cyclin D1 by the ERK pathway may provide a paradigm for understanding how cell adhesion can determine cell cycle progression.


Insects ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 624
Author(s):  
Li Chang ◽  
Zhiqing Li ◽  
Hao Guo ◽  
Wenchang Zhang ◽  
Weiqun Lan ◽  
...  

Background: Putrescine, spermidine, and spermine are polyamines that are ubiquitously distributed in prokaryotic and eukaryotic cells, which play important roles in cell proliferation and differentiation. Methods: We investigated the expression profiles of polyamine pathway genes by qRT-PCR in different tissues of the lepidopteran silkworm. The polyamine levels in cultured silkworm cells were measured by HPLC. Spermidine and polyamine biosynthetic inhibitors were used for treating the cultured silkworm cells in order to clarify their effects on cell cycle progression. Results: We identified the anabolic and catabolic enzymes that are involved in the polyamine biosynthetic pathway in silkworm. Transcriptional expression showed at least seven genes that were expressed in different silkworm tissues. Treatments of the cultured silkworm cells with spermidine or inhibitor mixtures of DFMO and MGBG induced or inhibited the expression of cell cycle-related genes, respectively, and thus led to changed progression of the cell cycle. Conclusions: The present study is the first to identify the polyamine pathway genes and to demonstrate the roles of polyamines on cell cycle progression via regulation of the expression of cell cycle genes in silkworm.


1999 ◽  
Vol 10 (3) ◽  
pp. 785-798 ◽  
Author(s):  
Andrés J. Garcı́a ◽  
Marı́a D. Vega ◽  
David Boettiger

Integrin-mediated cell adhesion to extracellular matrices provides signals essential for cell cycle progression and differentiation. We demonstrate that substrate-dependent changes in the conformation of adsorbed fibronectin (Fn) modulated integrin binding and controlled switching between proliferation and differentiation. Adsorption of Fn onto bacterial polystyrene (B), tissue culture polystyrene (T), and collagen (C) resulted in differences in Fn conformation as indicated by antibody binding. Using a biochemical method to quantify bound integrins in cultured cells, we found that differences in Fn conformation altered the quantity of bound α5 and β1integrin subunits but not αv or β3. C2C12 myoblasts grown on these Fn-coated substrates proliferated to different levels (B > T > C). Immunostaining for muscle-specific myosin revealed minimal differentiation on B, significant levels on T, and extensive differentiation on C. Differentiation required binding to the RGD cell binding site in Fn and was blocked by antibodies specific for this site. Switching between proliferation and differentiation was controlled by the levels of α5β1 integrin bound to Fn, and differentiation was inhibited by anti-α5, but not anti-αv, antibodies, suggesting distinct integrin-mediated signaling pathways. Control of cell proliferation and differentiation through conformational changes in extracellular matrix proteins represents a versatile mechanism to elicit specific cellular responses for biological and biotechnological applications.


2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Lionel Condé ◽  
Yulemi Gonzalez Quesada ◽  
Florence Bonnet-Magnaval ◽  
Rémy Beaujois ◽  
Luc DesGroseillers

AbstractBackgroundStaufen2 (STAU2) is an RNA binding protein involved in the posttranscriptional regulation of gene expression. In neurons, STAU2 is required to maintain the balance between differentiation and proliferation of neural stem cells through asymmetric cell division. However, the importance of controlling STAU2 expression for cell cycle progression is not clear in non-neuronal dividing cells. We recently showed that STAU2 transcription is inhibited in response to DNA-damage due to E2F1 displacement from theSTAU2gene promoter. We now study the regulation of STAU2 steady-state levels in unstressed cells and its consequence for cell proliferation.ResultsCRISPR/Cas9-mediated and RNAi-dependent STAU2 depletion in the non-transformed hTERT-RPE1 cells both facilitate cell proliferation suggesting that STAU2 expression influences pathway(s) linked to cell cycle controls. Such effects are not observed in the CRISPR STAU2-KO cancer HCT116 cells nor in the STAU2-RNAi-depleted HeLa cells. Interestingly, a physiological decrease in the steady-state level of STAU2 is controlled by caspases. This effect of peptidases is counterbalanced by the activity of the CHK1 pathway suggesting that STAU2 partial degradation/stabilization fines tune cell cycle progression in unstressed cells. A large-scale proteomic analysis using STAU2/biotinylase fusion protein identifies known STAU2 interactors involved in RNA translation, localization, splicing, or decay confirming the role of STAU2 in the posttranscriptional regulation of gene expression. In addition, several proteins found in the nucleolus, including proteins of the ribosome biogenesis pathway and of the DNA damage response, are found in close proximity to STAU2. Strikingly, many of these proteins are linked to the kinase CHK1 pathway, reinforcing the link between STAU2 functions and the CHK1 pathway. Indeed, inhibition of the CHK1 pathway for 4 h dissociates STAU2 from proteins involved in translation and RNA metabolism.ConclusionsThese results indicate that STAU2 is involved in pathway(s) that control(s) cell proliferation, likely via mechanisms of posttranscriptional regulation, ribonucleoprotein complex assembly, genome integrity and/or checkpoint controls. The mechanism by which STAU2 regulates cell growth likely involves caspases and the kinase CHK1 pathway.


2021 ◽  
Vol 12 (4) ◽  
Author(s):  
Chen-Hua Dong ◽  
Tao Jiang ◽  
Hang Yin ◽  
Hu Song ◽  
Yi Zhang ◽  
...  

AbstractColorectal cancer is the second common cause of death worldwide. Lamin B2 (LMNB2) is involved in chromatin remodeling and the rupture and reorganization of nuclear membrane during mitosis, which is necessary for eukaryotic cell proliferation. However, the role of LMNB2 in colorectal cancer (CRC) is poorly understood. This study explored the biological functions of LMNB2 in the progression of colorectal cancer and explored the possible molecular mechanisms. We found that LMNB2 was significantly upregulated in primary colorectal cancer tissues and cell lines, compared with paired non-cancerous tissues and normal colorectal epithelium. The high expression of LMNB2 in colorectal cancer tissues is significantly related to the clinicopathological characteristics of the patients and the shorter overall and disease-free cumulative survival. Functional analysis, including CCK8 cell proliferation test, EdU proliferation test, colony formation analysis, nude mouse xenograft, cell cycle, and apoptosis analysis showed that LMNB2 significantly promotes cell proliferation by promoting cell cycle progression in vivo and in vitro. In addition, gene set enrichment analysis, luciferase report analysis, and CHIP analysis showed that LMNB2 promotes cell proliferation by regulating the p21 promoter, whereas LMNB2 has no effect on cell apoptosis. In summary, these findings not only indicate that LMNB2 promotes the proliferation of colorectal cancer by regulating p21-mediated cell cycle progression, but also suggest the potential value of LMNB2 as a clinical prognostic marker and molecular therapy target.


2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Pan Wang ◽  
Sheng Gong ◽  
Jinyu Pan ◽  
Junwei Wang ◽  
Dewei Zou ◽  
...  

AbstractThere exists a consensus that combining hyperbaric oxygen (HBO) and chemotherapy promotes chemotherapy sensitivity in GBM cells. However, few studies have explored the mechanism involved. HIF1α and HIF2α are the two main molecules that contribute to GBM malignant progression by inhibiting apoptosis or maintaining stemness under hypoxic conditions. Moreover, Sox2, a marker of stemness, also contributes to GBM malignant progression through stemness maintenance or cell cycle arrest. Briefly, HIF1α, HIF2α and Sox2 are highly expressed under hypoxia and contribute to GBM growth and chemoresistance. However, after exposure to HBO for GBM, whether the expression of the above factors is decreased, resulting in chemosensitization, remains unknown. Therefore, we performed a series of studies and determined that the expression of HIF1α, HIF2α and Sox2 was decreased after HBO and that HBO promoted GBM cell proliferation through cell cycle progression, albeit with a decrease in stemness, thus contributing to chemosensitization via the inhibition of HIF1α/HIF2α-Sox2.


2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Wei Liu ◽  
Hongmiao Ren ◽  
Jihao Ren ◽  
Tuanfang Yin ◽  
Bing Hu ◽  
...  

Cholesteatoma is a benign keratinizing and hyper proliferative squamous epithelial lesion of the temporal bone. Epidermal growth factor (EGF) is one of the most important cytokines which has been shown to play a critical role in cholesteatoma. In this investigation, we studied the effects of EGF on the proliferation of keratinocytes and EGF-mediated signaling pathways underlying the pathogenesis of cholesteatoma. We examined the expressions of phosphorylated EGF receptor (p-EGFR), phosphorylated Akt (p-Akt), cyclinD1, and proliferating cell nuclear antigen (PCNA) in 40 cholesteatoma samples and 20 samples of normal external auditory canal (EAC) epithelium by immunohistochemical method. Furthermore,in vitrostudies were performed to investigate EGF-induced downstream signaling pathways in primary external auditory canal keratinocytes (EACKs). The expressions of p-EGFR, p-Akt, cyclinD1, and PCNA in cholesteatoma epithelium were significantly increased when compared with those of control subjects. We also demonstrated that EGF led to the activation of the EGFR/PI3K/Akt/cyclinD1 signaling pathway, which played a critical role in EGF-induced cell proliferation and cell cycle progression of EACKs. Both EGFR inhibitor AG1478 and PI3K inhibitor wortmannin inhibited the EGF-induced EGFR/PI3K/Akt/cyclinD1 signaling pathway concomitantly with inhibition of cell proliferation and cell cycle progression of EACKs. Taken together, our data suggest that the EGFR/PI3K/Akt/cyclinD1 signaling pathway is active in cholesteatoma and may play a crucial role in cholesteatoma epithelial hyper-proliferation. This study will facilitate the development of potential therapeutic targets for intratympanic drug therapy for cholesteatoma.


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