scholarly journals The cellular microenvironment and cell adhesion: a role for O-glycosylation

2011 ◽  
Vol 39 (1) ◽  
pp. 378-382 ◽  
Author(s):  
Liping Zhang ◽  
Kelly G. Ten Hagen

Glycosylation is one of the most abundant protein modifications in Nature, having roles in protein stability, secretion and function. Alterations in mucin-type O-glycosylation are responsible for a number of human diseases and developmental defects, as well as associated with certain types of cancer. However, the mechanistic role of this form of glycosylation in many of these instances is unclear. Here we describe how one glycosyltransferase responsible for initiating mucin-type O-glycosylation (PGANT3), specifically modulates integrin-mediated cell adhesion by influencing the secretion and localization of an integrin ligand. The integrin ligand Tiggrin, is normally O-glycosylated and localized to the basal matrix, where adhesion of two opposing cell layers takes place. In pgant3 mutants, Tiggrin is no longer O-glycosylated and fails to be properly secreted to the basal cell layer interface, resulting in disruption of proper cell adhesion. pgant3-mediated effects are dependent on the enzymatic activity of PGANT3 and cannot be rescued by another pgant family member, indicating a unique role for this glycosyltransferase. These results provide in vivo evidence for the role of O-glycosylation in the secretion of specific extracellular matrix proteins, which thereby influences the composition of the cellular ‘microenvironment’ and modulates cell adhesion events. The studies described in this review provide insight into the long-standing association between aberrant O-glycosylation and tumorigenesis, as changes in tumour environment and cell adhesion are hallmarks of cancer progression.

2020 ◽  
Vol 160 (11-12) ◽  
pp. 650-658
Author(s):  
Yichen Le ◽  
Yi He ◽  
Meirong Bai ◽  
Ying Wang ◽  
Jiaxue Wu ◽  
...  

Ajuba has been found to be mutated or aberrantly regulated in several human cancers and plays important roles in cancer progression via different signaling pathways. However, little is known about the role of Ajuba in hepatocellular carcinoma (HCC). Here, we found an upregulation of Ajuba expression in HCC tissues compared with normal liver tissues, while a poor prognosis was observed in HCC patients with high Ajuba expression. Knockout of Ajuba in HCC cells inhibited cell growth in vitro and in vivo, suppressed cell migration, and enhanced the cell apoptosis under stress. Moreover, re-expression of Ajuba in Ajuba-deficient cells could restore the phenotype of Ajuba-deficient cells. In conclusion, these results indicate that Ajuba is upregulated in HCC and promotes cell growth and migration of HCC cells, suggesting that Ajuba could possibly be a new target for HCC diagnosis and treatment.


2021 ◽  
Vol 16 (1) ◽  
pp. 1-13
Author(s):  
Weiwei Liu ◽  
Dongmei Yao ◽  
Bo Huang

Abstract Cervical cancer (CC) is a huge threat to the health of women worldwide. Long non-coding RNA plasmacytoma variant translocation 1 gene (PVT1) was proved to be associated with the development of diverse human cancers, including CC. Nevertheless, the exact mechanism of PVT1 in CC progression remains unclear. Levels of PVT1, microRNA-503 (miR-503), and ADP ribosylation factor-like protein 2 (ARL2) were measured by quantitative reverse transcription-polymerase chain reaction or western blot assay. 3-(4,5)-Dimethylthiazole-2-y1)-2,5-biphenyl tetrazolium bromide (MTT) and flow cytometry were used to examine cell viability and apoptosis, respectively. For migration and invasion detection, transwell assay was performed. The interaction between miR-503 and PVT1 or ARL2 was shown by dual luciferase reporter assay. A nude mouse model was constructed to clarify the role of PVT1 in vivo. PVT1 and ARL2 expressions were increased, whereas miR-503 expression was decreased in CC tissues and cells. PVT1 was a sponge of miR-503, and miR-503 targeted ARL2. PVT1 knockdown suppressed proliferation, migration, and invasion of CC cells, which could be largely reverted by miR-503 inhibitor. In addition, upregulated ARL2 could attenuate si-PVT1-mediated anti-proliferation and anti-metastasis effects on CC cells. Silenced PVT1 also inhibited CC tumor growth in vivo. PVT1 knockdown exerted tumor suppressor role in CC progression via the miR-503/ARL2 axis, at least in part.


Author(s):  
Jun-Xian Du ◽  
Yi-Hong Luo ◽  
Si-Jia Zhang ◽  
Biao Wang ◽  
Cong Chen ◽  
...  

Abstract Background Intensive evidence has highlighted the effect of aberrant alternative splicing (AS) events on cancer progression when triggered by dysregulation of the SR protein family. Nonetheless, the underlying mechanism in breast cancer (BRCA) remains elusive. Here we sought to explore the molecular function of SRSF1 and identify the key AS events regulated by SRSF1 in BRCA. Methods We conducted a comprehensive analysis of the expression and clinical correlation of SRSF1 in BRCA based on the TCGA dataset, Metabric database and clinical tissue samples. Functional analysis of SRSF1 in BRCA was conducted in vitro and in vivo. SRSF1-mediated AS events and their binding motifs were identified by RNA-seq, RNA immunoprecipitation-PCR (RIP-PCR) and in vivo crosslinking followed by immunoprecipitation (CLIP), which was further validated by the minigene reporter assay. PTPMT1 exon 3 (E3) AS was identified to partially mediate the oncogenic role of SRSF1 by the P-AKT/C-MYC axis. Finally, the expression and clinical significance of these AS events were validated in clinical samples and using the TCGA database. Results SRSF1 expression was consistently upregulated in BRCA samples, positively associated with tumor grade and the Ki-67 index, and correlated with poor prognosis in a hormone receptor-positive (HR+) cohort, which facilitated proliferation, cell migration and inhibited apoptosis in vitro and in vivo. We identified SRSF1-mediated AS events and discovered the SRSF1 binding motif in the regulation of splice switching of PTPMT1. Furthermore, PTPMT1 splice switching was regulated by SRSF1 by binding directly to its motif in E3 which partially mediated the oncogenic role of SRSF1 by the AKT/C-MYC axis. Additionally, PTPMT1 splice switching was validated in tissue samples of BRCA patients and using the TCGA database. The high-risk group, identified by AS of PTPMT1 and expression of SRSF1, possessed poorer prognosis in the stage I/II TCGA BRCA cohort. Conclusions SRSF1 exerts oncogenic roles in BRCA partially by regulating the AS of PTPMT1, which could be a therapeutic target candidate in BRCA and a prognostic factor in HR+ BRCA patient.


1983 ◽  
Vol 96 (2) ◽  
pp. 527-540 ◽  
Author(s):  
J Molè-Bajer ◽  
A S Bajer

We have studied the effect of taxol on mitosis in Haemanthus endosperm. Immuno-Gold Stain (IGS), a new immunocytochemical method (17), was used to visualize microtubules (MTs) in the light microscope. Observations on MT arrangements were correlated with studies in vivo. Chromosome movements are affected in all stages of mitosis which progresses over at least 10(4) range of taxol concentrations. The three most characteristic effects on MTs are: (a) enhancement of the lateral associations between MTs, seen especially during the reorganization of the polar region of the spindle, (b) promotion of MT assembly, leading to the formation of additional MTs in the spindle and MT arrays in the cytoplasm, and (c) an increase in MT stability, demonstrated in their increased cold resistance. In this report, the emphasis is on the primary, immediate effects, occurring in the first 30 min of taxol action. Effects are detected after a few mins, are reversible, and are concentration/time dependent. The spindle and phragmoplast are remarkably modified due to the enhancement of lateral associations of MTs and the formation of abundant nonkinetochore and polar, asterlike MTs. The equatorial region of the interzone in anaphase may be entirely depleted of MTs, and the spindle may break perpendicular to the spindle axis. Mitosis is completed in these conditions, providing evidence for the motile autonomy of each half-spindle. Trailing chromosome arms in anaphase are often stretched and broken. Chromosome fragments are transported away from the polar regions, i.e., in the direction opposite to that expected (5, 6). This supplies the first direct evidence of pushing by elongating MTs in an anastral higher plant spindle. These observations draw attention to the relation between the lateral association of MT ends to assembly/disassembly and to the role of such an interaction in spindle function and organization.


Diabetes ◽  
2012 ◽  
Vol 61 (7) ◽  
pp. 1708-1718 ◽  
Author(s):  
E. P. Cai ◽  
M. Casimir ◽  
S. A. Schroer ◽  
C. T. Luk ◽  
S. Y. Shi ◽  
...  

Biomedicines ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 168
Author(s):  
Susanna Fiorelli ◽  
Nicola Cosentino ◽  
Benedetta Porro ◽  
Franco Fabbiocchi ◽  
Giampaolo Niccoli ◽  
...  

Netrin-1 is a laminin-like protein that plays a pivotal role in cell migration and, according to the site of its release, exerts both pro and anti-atherosclerotic functions. Macrophages, key cells in atherosclerosis, are heterogeneous in morphology and function and different subpopulations may support plaque progression, stabilization, and/or regression. Netrin-1 was evaluated in plasma and, together with its receptor UNC5b, in both spindle and round monocyte-derived macrophages (MDMs) morphotypes from coronary artery disease (CAD) patients and control subjects. In CAD patients, plaque features were detected in vivo by optical coherence tomography. CAD patients had lower plasma Netrin-1 levels and a higher MDMs expression of both protein and its receptor compared to controls. Specifically, a progressive increase in Netrin-1 and UNC5b was evidenced going from controls to stable angina (SA) and acute myocardial infarction (AMI) patients. Of note, spindle MDMs of AMI showed a marked increase of both Netrin-1 and its receptor compared to spindle MDMs of controls. UNC5b expression is always higher in spindle compared to round MDMs, regardless of the subgroup. Finally, CAD patients with higher intracellular Netrin-1 levels showed greater intraplaque macrophage accumulation in vivo. Our findings support the role of Netrin-1 and UNC5b in the atherosclerotic process.


1995 ◽  
Vol 2 (3) ◽  
pp. 401-411 ◽  
Author(s):  
Carolyn J. Sympson ◽  
Rabih S. Talhouk ◽  
Mina J. Bissell ◽  
Zena Werb

Author(s):  
Tiziana Schioppa ◽  
Francesca Sozio ◽  
Ilaria Barbazza ◽  
Sara Scutera ◽  
Daniela Bosisio ◽  
...  

CCRL2 is a seven-transmembrane domain receptor that belongs to the chemokine receptor family. At difference from other members of this family, CCRL2 does not promote chemotaxis and shares structural features with atypical chemokine receptors (ACKRs). However, CCRL2 also differs from ACKRs since it does not bind chemokines and is devoid of scavenging functions. The only commonly recognized CCRL2 ligand is chemerin, a non-chemokine chemotactic protein. CCRL2 is expressed both by leukocytes and non-hematopoietic cells. The genetic ablation of CCRL2 has been instrumental to elucidate the role of this receptor as positive or negative regulator of inflammation. CCRL2 modulates leukocyte migration by two main mechanisms. First, when CCRL2 is expressed by barrier cells, such endothelial, and epithelial cells, it acts as a presenting molecule, contributing to the formation of a non-soluble chemotactic gradient for leukocytes expressing CMKLR1, the functional chemerin receptor. This mechanism was shown to be crucial in the induction of NK cell-dependent immune surveillance in lung cancer progression and metastasis. Second, by forming heterocomplexes with other chemokine receptors. For instance, CCRL2/CXCR2 heterodimers were shown to regulate the activation of β2-integrins in mouse neutrophils. This mini-review summarizes the current understanding of CCRL2 biology, based on experimental evidence obtained by the genetic deletion of this receptor in in vivo experimental models. Further studies are required to highlight the complex functional role of CCRL2 in different organs and pathological conditions.


2020 ◽  
Author(s):  
Hui Guo ◽  
Jianping Zou ◽  
Ling Zhou ◽  
Yan He ◽  
Miao Feng ◽  
...  

Abstract Background:Nucleolar and spindle associated protein (NUSAP1) is involved in tumor initiation, progression and metastasis. However, there are limited studies regarding the role of NUSAP1 in gastric cancer (GC). Methods: The expression profile and clinical significance of NUSAP1 in GC were analysed in online database using GEPIA, Oncomine and KM plotter, which was further confirmed in clinical specimens.The functional role of NUSAP1 were detected utilizing in vitro and in vivo assays. Western blotting, qRT-PCR, the cycloheximide-chase, immunofluorescence staining and Co-immunoprecipitaion (Co-IP) assays were performed to explore the possible molecular mechanism by which NUSAP1 stabilizes YAP protein. Results:In this study, we found that the expression of NUSAP1 was upregulated in GC tissues and correlates closely with progression and prognosis. Additionally, abnormal NUSAP1 expression promoted malignant behaviors of GC cells in vitro and in a xenograft model. Mechanistically, we discovered that NUSAP1 physically interacts with YAP and furthermore stabilizes YAP protein expression, which induces the transcription of Hippo pathway downstream target genes. Furthermore, the effects of NUSAP1 on GC cell growth, migration and invasion were mainly mediated by YAP. Conclusions:Our data demonstrates that the novel NUSAP1-YAP axis exerts an critical role in GC tumorigenesis and progression, and therefore could provide a novel therapeutic target for GC treatment.


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