scholarly journals Mechanosensitive Expression of Lamellipodin Governs Cell Cycle Progression and Intracellular Stiffness

2020 ◽  
Author(s):  
Joseph A. Brazzo ◽  
Kwonmoo Lee ◽  
Yongho Bae

SUMMARYCells exhibit pathological behaviors in response to increased extracellular matrix (ECM) stiffness, including accelerated cell proliferation and migration [1–9], which are correlated with increased intracellular stiffness and tension [2, 3, 10–12]. The biomechanical signal transduction of ECM stiffness into relevant molecular signals and resultant cellular processes is mediated through multiple proteins associated with the actin cytoskeleton in lamellipodia [2, 3, 10, 11, 13]. However, the molecular mechanisms by which lamellipodial dynamics regulate cellular responses to ECM stiffening remain unclear. Previous work described that lamellipodin, a phosphoinositide- and actin filament-binding protein that is known mostly for controlling cell migration [14–21], promotes ECM stiffness-mediated early cell cycle progression [2], revealing a potential commonality between the mechanisms controlling stiffness-dependent cell migration and those controlling cell proliferation. However, i) whether and how ECM stiffness affects the levels of lamellipodin expression and ii) whether stiffness-mediated lamellipodin expression is required throughout cell cycle progression and for intracellular stiffness have not been explored. Here, we show that the levels of lamellipodin expression in cells are significantly increased by a stiff ECM and that this stiffness-mediated lamellipodin upregulation persistently stimulates cell cycle progression and intracellular stiffness throughout the cell cycle, from the early G1 phase to M phase. Finally, we show that both Rac activation and intracellular stiffening are required for the mechanosensitive induction of lamellipodin. More specifically, inhibiting Rac1 activation in cells on stiff ECM reduces the levels of lamellipodin expression, and this effect is reversed by the overexpression of activated Rac1 in cells on soft ECM. We thus propose that lamellipodin is a critical molecular lynchpin in the control of mechanosensitive cell cycle progression and intracellular stiffness.

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.


2004 ◽  
Vol 287 (1) ◽  
pp. C125-C134 ◽  
Author(s):  
Halima Ouadid-Ahidouch ◽  
Morad Roudbaraki ◽  
Philippe Delcourt ◽  
Ahmed Ahidouch ◽  
Nathalie Joury ◽  
...  

We have previously reported that the hEAG K+ channels are responsible for the potential membrane hyperpolarization that induces human breast cancer cell progression into the G1 phase of the cell cycle. In the present study, we evaluate the role and functional expression of the intermediate-conductance Ca2+-activated K+ channel, hIK1-like, in controlling cell cycle progression. Our results demonstrate that hIK1 current density increased in cells synchronized at the end of the G1 or S phase compared with those in the early G1 phase. This increased current density paralleled the enhancement in hIK1 mRNA levels and the highly negative membrane potential. Furthermore, in cells synchronized at the end of G1 or S phases, basal cytosolic Ca2+ concentration ([Ca2+]i) was also higher than in cells arrested in early G1. Blocking hIK1 channels with a specific blocker, clotrimazole, induced both membrane potential depolarization and a decrease in the [Ca2+]i in cells arrested at the end of G1 and S phases but not in cells arrested early in the G1 phase. Blocking hIK1 with clotrimazole also induced cell proliferation inhibition but to a lesser degree than blocking hEAG with astemizole. The two drugs were essentially additive, inhibiting MCF-7 cell proliferation by 82% and arresting >90% of cells in the G1 phase. Thus, although the progression of MCF-7 cells through the early G1 phase is dependent on the activation of hEAG K+ channels, when it comes to G1 and checkpoint G1/S transition, the membrane potential appears to be primarily dependent on the hIK1-activity level.


2005 ◽  
Vol 79 (16) ◽  
pp. 10750-10763 ◽  
Author(s):  
J. B. Johnston ◽  
G. Wang ◽  
J. W. Barrett ◽  
S. H. Nazarian ◽  
K. Colwill ◽  
...  

ABSTRACT The myxoma virus (MV) M-T5 gene encodes an ankyrin repeat protein that is important for virus replication in cells from several species. Insight was gained into the molecular mechanisms underlying the role of M-T5 as a host range determinant when the cell cycle regulatory protein cullin-1 (cul-1) was identified as a cellular binding partner of M-T5 and found to colocalize with the protein in both nuclear and cytosolic compartments. Consistent with this interaction, infection with wild-type MV (vMyxlac) or a deletion mutant lacking M-T5 (vMyxT5KO) differentially altered cell cycle progression in a panel of permissive and nonpermissive cells. Cells infected with vMyxlac transitioned rapidly out of the G0/G1 phase and preferentially accumulated at the G2/M checkpoint, whereas infection with vMyxT5KO impeded progression through the cell cycle, resulting in a greater percentage of cells retained at G0/G1. Levels of the cul-1 substrate, p27/Kip-1, were selectively increased in cells infected with vMyxT5KO compared to vMyxlac, concurrent with decreased phosphorylation of p27/Kip-1 at Thr187 and decreased ubiquitination. Compared to cells infected with vMyxlac, cell death was increased in vMyxT5KO-infected cells following treatment with diverse stimuli known to induce cell cycle arrest, including infection itself, serum deprivation, and exposure to proteasome inhibitors or double-stranded RNA. Moreover, infection with vMyxlac, but not vMyxT5KO, was sufficient to overcome the G0/G1 arrest induced by these stimuli. These findings suggest that M-T5 regulates cell cycle progression at the G0/G1 checkpoint, thereby protecting infected cells from diverse innate host antiviral responses normally triggered by G0/G1 cell cycle arrest.


RNA ◽  
2021 ◽  
pp. rna.078935.121
Author(s):  
Elena Martin ◽  
Claudia Vivori ◽  
Malgorzata Rogalska ◽  
Jorge Herrero ◽  
Juan Valcarcel

The regulation of pre-mRNA processing has important consequences for cell division and the control of cancer cell proliferation but the underlying molecular mechanisms remain poorly understood. We report that three splicing factors, SPF45, SR140 and CHERP form a tight physical and functionally coherent complex that regulates a variety of alternative splicing events, frequently by repressing short exons flanked by suboptimal 3' splice sites. These comprise alternative exons embedded in genes with important functions in cell cycle progression, including the G2/M key regulator FOXM1 and the spindle regulator SPDL1. Knockdown of either of the three factors leads to G2/M arrest and to enhanced apoptosis in HeLa cells. Promoting the changes in FOXM1 or SPDL1 splicing induced by SPF45/SR140/CHERP knockdown partially recapitulate the effects on cell growth, arguing that the complex orchestrates a program of alternative splicing necessary for efficient cell proliferation.


Author(s):  
Hye-Won Jung ◽  
Inae Park ◽  
Sungho Ghil

AbstractCannabinoids display various pharmacological activities, including tumor regression, anti-inflammatory and neuroprotective effects. To investigate the molecular mechanisms underlying the pharmacological effects of cannabinoids, we used a yeast two-hybrid system to screen a mouse brain cDNA library for proteins interacting with type 1 cannabinoid receptor (CB1R). Using the intracellular loop 3 of CB1R as bait, we identified 14-3-3β as an interacting partner of CB1R and confirmed their interaction using affinity-binding assays. 14-3-3β has been reported to induce a cell cycle delay at the G2/M phase. We tested the effects of cannabinoids on cell cycle progression in HeLa cells synchronized using a double-thymidine block-and-release protocol and found an increase in the population of G2/M phase cells. We further found that CB1R activation augmented the interaction of 14-3-3β with Wee1 and Cdc25B, and promoted phosphorylation of Cdc2 at Tyr-15. These results suggest that cannabinoids induce cell cycle delay at the G2/M phase by activating 14-3-3β.


Cells ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 657 ◽  
Author(s):  
Ilaria Cristofaro ◽  
Francesco Alessandrini ◽  
Zaira Spinello ◽  
Claudia Guerriero ◽  
Mario Fiore ◽  
...  

Glioblastomas (GBM) are the most aggressive form of primary brain tumors in humans. A key feature of malignant gliomas is their cellular heterogeneity. In particular, the presence of an undifferentiated cell population of defined Glioblastoma Stem cells (GSCs) was reported. Increased expression of anti-apoptotic and chemo-resistance genes in GCSs subpopulation favors their high resistance to a broad spectrum of drugs. Our previous studies showed the ability of M2 muscarinic receptors to negatively modulate the cell growth in GBM cell lines and in the GSCs. The aim of this study was to better characterize the inhibitory effects of M2 receptors on cell proliferation and survival in GSCs and investigate the molecular mechanisms underlying the M2-mediated cell proliferation arrest and decreased survival. Moreover, we also evaluated the ability of M2 receptors to interfere with Notch1 and EGFR pathways, whose activation promotes GSCs proliferation. Our data demonstrate that M2 receptors activation impairs cell cycle progression and survival in the primary GSC lines analyzed (GB7 and GB8). Moreover, we also demonstrated the ability of M2 receptor to inhibit Notch1 and EGFR expression, highlighting a molecular interaction between M2 receptor and the Notch-1/EGFR pathways also in GSCs.


2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Jaeyong Kang ◽  
Hansaem Kim ◽  
Hyangsoon Noh ◽  
Byung-Ha Kang ◽  
Jaejik Kim ◽  
...  

AbstractObjectivesBreast cancer (BC) is the most commonly diagnosed cancer in women worldwide with a high mortality rate, despite early detection and treatment. Spindle and kinetochore-associated complex subunit 3 (SKA3) is closely correlated with patient outcomes in several cancers. The present study aimed to elucidate the role of SKA3 in BC.MethodsThe biological functions of SKA3 was investigated by proliferation and migration assays in MDA-MB-231 cells with stable SKA3 knockdown and Hs578T cells ectopically expressing SKA3. Gene Expression Omnibus datasets were utilised to determine the correlation between SKA3 expression and clinical features of BC patients.ResultsWe confirmed that SKA3 mRNA expression is higher in breast tumour tissue than in normal tissue, and that higher SKA3 expression is associated with poor survival rate of BC patients. Knockdown of SKA3 reduced MDA-MB-231 cell proliferation and migration, whereas SKA3 overexpression enhanced the proliferative and migratory ability of Hs578T cells. We also found that SKA3 is involved in regulating cell cycle progression in mitotic exit.ConclusionsThese results suggest that SKA3 is correlated with BC cell proliferation and migration by promoting cell cycle progression, and could be a novel potential therapeutic target for BC treatment.


2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Nana Liu ◽  
Shuo Guan ◽  
Hongyan Wang ◽  
Chen Li ◽  
Jyawei Cheng ◽  
...  

Objective. The primary purpose of this study was to evaluate the reparative efficacy of a novel antimicrobial peptide, Nal-P-113, in shortening the healing time of oral mucosal ulcers by promoting cell proliferation and migration and accelerating the cell cycle. Methods. Cell counting kit-8 (CCK-8) and wound-healing assays were used to evaluate the proliferation and migration of human immortalized oral epithelial cells (HIOECs). The cell cycle distribution of HIOECs was analyzed by flow cytometry. Additionally, the RNA levels of EGF, FGF-2, and TGF-β1 of HIOECs were assessed by real-time PCR. Rats were divided into three groups randomly: (a) blank control group; (b) 20 μg/mL Nal-P-113; and (c) 10 ng/mL rhEGF. An oral mucosal ulcer was induced in every rat by the application of 30% acetic acid. An immunohistochemical assay was used to assess the expression of EGF, FGF-2, and TGF-β1 in the rat oral mucosa. Results. In the CCK-8 assay, the optical density values in the Nal-P-113 and rhEGF groups were found to be significantly higher than that in the blank control group. In addition, the scratch areas in the Nal-P-113 and rhEGF groups were found to be significantly smaller (P<0.05). Cell cycle analysis showed that Nal-P-113 accelerated the entry of HIOECs into the S phase and expedited their cell cycles. The RT-PCR results suggested that Nal-P-113 upregulated the RNA levels of EGF and FGF-2 but downregulated that of TGF-β1 at 24 h and 48 h. Lastly, the immunohistochemical assay verified that Nal-P-113 changed the expression of the above cytokines in rat mucosal ulcers. Conclusion. Nal-P-113 promoted the repair of oral mucosal ulcers by increasing the EGF and FGF-2 expression and decreasing that of TGF-β1 in HIOECs, accelerating their proliferation and cell cycle progression. The application of Nal-P-113 might serve as an effective therapeutic approach for recurrent aphthous stomatitis.


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