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Pediatric Hematology and Oncology May 2017Neuroblastoma (NB) often presents with metastatic disease and poor survival. The need for new prognostic markers remains invaluable. The FAK-Src-Paxillin protein system...
BACKGROUND
Neuroblastoma (NB) often presents with metastatic disease and poor survival. The need for new prognostic markers remains invaluable. The FAK-Src-Paxillin protein system is associated with aggressive phenotype in adult malignancies but is largely unexplored in pediatric NB.
OBJECTIVE
To assess FAK-Src-Paxillin protein expression in human NB cell lines and clinical cytology material and to delineate its association with survival.
DESIGN/METHODS
Western blot and immunohistochemistry were applied for FAK-Src-Paxillin expression in NB cell lines and 23 human cytology specimens, respectively. Protein expression in human clinical samples was correlated with clinicopathological parameters, MYCN amplification and survival.
RESULTS
FAK, Src and Paxillin proteins are expressed in human NB cells lines, and can be detected in clinical cytology specimens from NB patients, (59%, 32% and 33% respectively). Simultaneous FAK-Src-Paxillin expression was noted in 30% of NB patients. Children with concomitant positivity FAK, Src, and Paxillin tumors, as well as MYCN amplification, had increased mortality compared to those without.
CONCLUSIONS
FAK-Src-Paxillin system is a marker of unfavorable prognosis for human NB patients but also a promising therapeutic target.
Topics: Animals; Biomarkers, Tumor; Child; Child, Preschool; Disease-Free Survival; Female; Focal Adhesion Kinase 1; Gene Expression Regulation, Neoplastic; Humans; Infant; K562 Cells; Male; Mice; N-Myc Proto-Oncogene Protein; NIH 3T3 Cells; Neuroblastoma; Paxillin; Proto-Oncogene Proteins pp60(c-src); Survival Rate
PubMed: 29040002
DOI: 10.1080/08880018.2017.1360969 -
Journal of Oral and Maxillofacial... 2022Cell adhesion molecules are essential to maintain the integrity of stratified squamous epithelium but their expression has to be dynamic to aid the mobility and turnover...
BACKGROUND
Cell adhesion molecules are essential to maintain the integrity of stratified squamous epithelium but their expression has to be dynamic to aid the mobility and turnover of cells. Paxillin is one such multi-domain protein which integrates numerous signals from cell surface receptors, integrins and growth factors. It thus functions as a regulator of various physiological and pathological processes including tissue remodeling, cell motility, gene expression, matrix organization, cell proliferation, metastasis and survival. Hence, the assessment of paxillin expression in normal control, potentially malignant disorders and oral squamous cell carcinoma patients was carried out.
MATERIAL AND METHODS
The present retrospective study comprised of 20 each clinically and histologically confirmed case of normal control, potentially malignant disorders, and oral squamous cell carcinomas. All the slides were stained immunohistochemically using Paxillin antibody.
RESULTS
The localization, staining intensity and percentage of positivity for paxillin expression was statistically significant among normal control and potentially malignant disorders, whereas oral squamous cell carcinoma showed a non-significant difference. Upon comparison of histopathological grading of potentially malignant disorders, mild versus severe and moderate versus severe epithelial dysplasia showed a statistical significant difference among all the parameters of paxillin expression. However, WDSCC & MDSCC a statistically significant difference among localization and staining intensity of paxillin.
CONCLUSION
Paxillin may play an important role in pathogenesis of oral squamous cell carcinoma by altering the adhesive properties of the tumor cells interacting with the extracellular matrix which in turn affects their invasive behavior and histologic differentiation.
PubMed: 36588853
DOI: 10.4103/jomfp.jomfp_187_21 -
Histochemistry and Cell Biology Sep 2014Focal adhesion kinase (FAK) and paxillin are functionally linked hormonal- and mechano-sensitive proteins. We aimed to describe paxillin's subcellular distribution using...
Focal adhesion kinase (FAK) and paxillin are functionally linked hormonal- and mechano-sensitive proteins. We aimed to describe paxillin's subcellular distribution using widefield and confocal immunofluorescence microscopy and test the hypothesis that FAK and paxillin colocalise in human skeletal muscle and its associated microvasculature. Percutaneous muscle biopsies were collected from the m. vastus lateralis of seven healthy males, and 5-μm cryosections were stained with anti-paxillin co-incubated with anti-dystrophin to identify the sarcolemma, anti-myosin heavy chain type I for fibre-type differentiation, anti-dihydropyridine receptor to identify T-tubules, lectin UEA-I to identify the endothelium of microvessels and anti-α-smooth muscle actin to identify vascular smooth muscle cells (VSMC). Colocalisation of anti-paxillin with anti-dystrophin or anti-FAK was quantified using Pearson's correlation coefficient on confocal microscopy images. Paxillin was primarily present in (sub)sarcolemmal regions of skeletal muscle fibres where it colocalised with dystrophin (r = 0.414 ± 0.026). The (sub)sarcolemmal paxillin immunofluorescence intensity was ~2.4-fold higher than in sarcoplasmic regions (P < 0.001) with sarcoplasmic paxillin immunofluorescence intensity ~10 % higher in type I than in type II fibres (P < 0.01). In some longitudinally orientated fibres, paxillin formed striations that corresponded to the I-band region. Paxillin immunostaining was highest in endothelial and VSMC and distributed heterogeneously in both cell types. FAK and paxillin colocalised at (sub)sarcolemmal regions and within the microvasculature (r = 0.367 ± 0.036). The first images of paxillin in human skeletal muscle suggest paxillin is present in (sub)sarcolemmal and I-band regions of muscle fibres and within the microvascular endothelium and VSMC. Colocalisation of FAK and paxillin supports their suggested role in hormonal and mechano-sensitive signalling.
Topics: Adult; Fluorescent Antibody Technique; Focal Adhesion Kinase 1; Humans; Male; Microvessels; Muscle, Skeletal; Paxillin; Young Adult
PubMed: 24671495
DOI: 10.1007/s00418-014-1212-3 -
Development (Cambridge, England) May 2019Establishing apical-basal epithelial cell polarity is fundamental for mammary gland duct morphogenesis during mammalian development. While the focal adhesion adapter...
Establishing apical-basal epithelial cell polarity is fundamental for mammary gland duct morphogenesis during mammalian development. While the focal adhesion adapter protein paxillin is a well-characterized regulator of mesenchymal cell adhesion signaling, F-actin cytoskeleton remodeling and single cell migration, its role in epithelial tissue organization and mammary gland morphogenesis has not been investigated. Here, using a newly developed paxillin conditional knockout mouse model with targeted ablation in the mammary epithelium, in combination with three-dimensional organoid and acini cultures, we identify new roles for paxillin in the establishment of apical-basal epithelial cell polarity and lumen formation, as well as mammary gland duct diameter and branching. Paxillin is shown to be required for the integrity and apical positioning of the Golgi network, Par complex and the Rab11/MyoVb trafficking machinery. Paxillin depletion also resulted in reduced levels of apical acetylated microtubules, and rescue experiments with the HDAC6 inhibitor tubacin highlight the central role for paxillin-dependent regulation of HDAC6 activity and associated microtubule acetylation in controlling epithelial cell apical-basal polarity and tissue branching morphogenesis.
Topics: Animals; Cell Movement; Cell Polarity; Epithelial Cells; Extracellular Matrix; Mammary Glands, Animal; Mice; Microtubules; Morphogenesis; Paxillin; Signal Transduction
PubMed: 30967426
DOI: 10.1242/dev.174367 -
The Journal of Cell Biology Apr 2024Focal adhesions (FAs) are transmembrane protein assemblies mediating cell-matrix connection. Although protein liquid-liquid phase separation (LLPS) has been tied to the...
Focal adhesions (FAs) are transmembrane protein assemblies mediating cell-matrix connection. Although protein liquid-liquid phase separation (LLPS) has been tied to the organization and dynamics of FAs, the underlying mechanisms remain unclear. Here, we experimentally tune the LLPS of PXN/Paxillin, an essential scaffold protein of FAs, by utilizing a light-inducible Cry2 system in different cell types. In addition to nucleating FA components, light-triggered PXN LLPS potently activates integrin signaling and subsequently accelerates cell spreading. In contrast to the homotypic interaction-driven LLPS of PXN in vitro, PXN condensates in cells are associated with the plasma membrane and modulated by actomyosin contraction and client proteins of FAs. Interestingly, non-specific weak intermolecular interactions synergize with specific molecular interactions to mediate the multicomponent condensation of PXN and are efficient in promoting FA assembly and integrin signaling. Thus, our data establish an active role of the PXN phase transition into a condensed membrane-associated compartment in promoting the assembly/maturation of FAs.
Topics: Humans; Actin Cytoskeleton; Focal Adhesions; Integrins; Paxillin; Phase Separation
PubMed: 38466167
DOI: 10.1083/jcb.202209027 -
Molecular Biology of the Cell Dec 2017Cell polarization and directed migration play pivotal roles in diverse physiological and pathological processes. Herein, we identify new roles for paxillin-mediated...
Cell polarization and directed migration play pivotal roles in diverse physiological and pathological processes. Herein, we identify new roles for paxillin-mediated HDAC6 inhibition in regulating key aspects of cell polarization in both two-dimensional and one-dimensional matrix environments. Paxillin, by modulating microtubule acetylation through HDAC6 regulation, was shown to control centrosome and Golgi reorientation toward the leading edge, a hallmark of cell polarization to ensure directed trafficking of promigratory factors. Paxillin was also required for pericentrosomal Golgi localization and centrosome cohesion, independent of its localization to, and role in, focal adhesion signaling. In addition, we provide evidence of an accumulation of paxillin at the centrosome that is dependent on focal adhesion kinase (FAK) and identify an important collaboration between paxillin and FAK signaling in the modulation of microtubule acetylation, as well as centrosome and Golgi organization and polarization. Finally, paxillin was also shown to be required for optimal anterograde vesicular trafficking to the plasma membrane.
Topics: Cell Adhesion; Cell Line, Tumor; Cell Movement; Cell Polarity; Centrosome; Cytoskeletal Proteins; Extracellular Matrix; Focal Adhesion Kinase 1; Focal Adhesion Protein-Tyrosine Kinases; Focal Adhesions; Golgi Apparatus; Histone Deacetylase 6; Humans; Paxillin; Phosphoproteins; Phosphorylation; Protein Processing, Post-Translational; Signal Transduction
PubMed: 29046398
DOI: 10.1091/mbc.E17-08-0488 -
Anticancer Research Feb 2024Colorectal cancer (CRC) is the third most common cancer worldwide, and metastasis is strongly associated with poor prognosis in patients with CRC. We have previously...
BACKGROUND/AIM
Colorectal cancer (CRC) is the third most common cancer worldwide, and metastasis is strongly associated with poor prognosis in patients with CRC. We have previously found that the expression and phosphorylation of paxillin (PXN) play an important role in the metastatic potential of breast cancer. This study examined the potential role of PXN in CRC metastasis.
MATERIALS AND METHODS
Resected tumor specimens from 92 patients with CRC were subjected to immunohistochemical analysis of PXN levels. Three human CRC cell lines, HCT116, LoVo, and SW480 were used for scratch and transwell invasion assays to examine the effects of PXN over-expression. RNA sequencing was performed to obtain the expression profiles under PXN over-expression.
RESULTS
High levels of PXN were significantly correlated with advanced stage, higher carcinoembryonic antigen and carbohydrate antigen 19-9 levels, and poorer overall survival. The migration ability of CRC cells was enhanced by exogenous PXN over-expression, but this enhancement was not observed in cells harboring exogenously mutated PXN at Tyr31 or Tyr88 phosphorylation sites. In PXN-over-expressing cells, TNF-α signaling via NF-[Formula: see text]B was positively enriched.
CONCLUSION
PXN expression and phosphorylation at Tyr31 or Tyr88 may influence the migration and invasion of CRC cells. PXN expression and phosphorylation at Tyr31 or Tyr88 are promising targets for evaluating prognosis and treating CRC.
Topics: Humans; Cell Line, Tumor; Cell Movement; Cell Proliferation; Colorectal Neoplasms; Gene Expression Regulation, Neoplastic; Neoplasm Metastasis; Paxillin; Phosphorylation; Prognosis
PubMed: 38307570
DOI: 10.21873/anticanres.16839 -
Asian Pacific Journal of Cancer... Jul 2022Glioblastoma is the most aggressive and lethal brain tumor in adults with highly invasive properties. In this present study, we explored the effects of Phyllanthus...
OBJECTIVE
Glioblastoma is the most aggressive and lethal brain tumor in adults with highly invasive properties. In this present study, we explored the effects of Phyllanthus taxodiifolius Beille extract on molecules known to be hallmarks of aggressive glioblastoma including N-cadherin and vimentin, mesenchymal markers, as well as paxillin, a major adaptor protein that regulates the linking of focal adhesions to the actin cytoskeleton.
METHODS
P. taxodiifolius were air-dried, powdered and percolated with methanol, filtered, concentrated and lyophilized to yield a crude methanol extract. C6 glioblastoma cell line was used in this study. The expression of N-cadherin and vimentin, as well as the activation of paxillin was determined using Western blot analysis. The effect of the extract on focal adhesions and actin cytoskeleton were investigated using immunofluorescence staining and confocal imaging.
RESULTS
In the presence of 40 µg/ml Phyllanthus taxodiifolius Beille extract, the expression of N-cadherin and vimentin were significantly decreased (p<0.001 and p<0.05, respectively). Activation of paxillin was also diminished as indicated by a reduction of phosphorylated-paxillin (p<0.01). Consequently, actin stress fibers in glioblastoma cells were abolished as evidenced by the decrease in focal adhesion (p<0.001) and stress fibers numbers (p<0.001).
CONCLUSION
Our study demonstrates for the first time that P. taxodiifolius interferes with multiple key molecules related to pathological hallmarks of glioblastoma. These molecules are involved with cell contacts, focal adhesions, and the formation and stabilization of actin stress fibers, which are required for glioblastoma metastatic behavior. These results provide further evidence supporting the potential of P. taxodiifolius and its bioactive compounds as anti-cancer agents.
Topics: Actins; Cadherins; Cell Adhesion; Focal Adhesion Protein-Tyrosine Kinases; Glioblastoma; Humans; Methanol; Paxillin; Phosphoproteins; Phosphorylation; Phyllanthus; Plant Extracts; Stress Fibers; Vimentin
PubMed: 35901345
DOI: 10.31557/APJCP.2022.23.7.2379 -
The Journal of Cell Biology Jan 2020Talin, vinculin, and paxillin are core components of the dynamic link between integrins and actomyosin. Here, we study the mechanisms that mediate their activation and...
Talin, vinculin, and paxillin are core components of the dynamic link between integrins and actomyosin. Here, we study the mechanisms that mediate their activation and association using a mitochondrial-targeting assay, structure-based mutants, and advanced microscopy. As expected, full-length vinculin and talin are autoinhibited and do not interact with each other. However, contrary to previous models that propose a critical role for forces driving talin-vinculin association, our data show that force-independent relief of autoinhibition is sufficient to mediate their tight interaction. We also found that paxillin can bind to both talin and vinculin when either is inactive. Further experiments demonstrated that adhesions containing paxillin and vinculin can form without talin following integrin activation. However, these are largely deficient in exerting traction forces to the matrix. Our observations lead to a model whereby paxillin contributes to talin and vinculin recruitment into nascent adhesions. Activation of the talin-vinculin axis subsequently leads to the engagement with the traction force machinery and focal adhesion maturation.
Topics: Actin Cytoskeleton; Animals; Cells, Cultured; Fibroblasts; Focal Adhesions; Mice; Mice, Inbred C57BL; Mice, Knockout; Paxillin; Protein Binding; Stress, Mechanical; Talin; Vinculin
PubMed: 31816055
DOI: 10.1083/jcb.201903134 -
Skeletal Muscle Aug 2019Secondary dystroglycanopathies are muscular dystrophies that result from mutations in genes that participate in Dystroglycan glycosylation. Glycosylation of Dystroglycan... (Review)
Review
BACKGROUND
Secondary dystroglycanopathies are muscular dystrophies that result from mutations in genes that participate in Dystroglycan glycosylation. Glycosylation of Dystroglycan is essential for muscle fibers to adhere to the muscle extracellular matrix (myomatrix). Although the myomatrix is disrupted in a number of secondary dystroglycanopathies, it is unknown whether improving the myomatrix is beneficial for these conditions. We previously determined that either NAD+ supplementation or overexpression of Paxillin are sufficient to improve muscle structure and the myomatrix in a zebrafish model of primary dystroglycanopathy. Here, we investigate how these modulations affect neuromuscular phenotypes in zebrafish fukutin-related protein (fkrp) morphants modeling FKRP-associated secondary dystroglycanopathy.
RESULTS
We found that NAD+ supplementation prior to muscle development improved muscle structure, myotendinous junction structure, and muscle function in fkrp morphants. However, Paxillin overexpression did not improve any of these parameters in fkrp morphants. As movement also requires neuromuscular junction formation, we examined early neuromuscular junction development in fkrp morphants. The length of neuromuscular junctions was disrupted in fkrp morphants. NAD+ supplementation prior to neuromuscular junction development improved length. We investigated NMJ formation in dystroglycan (dag1) morphants and found that although NMJ morphology is disrupted in dag1 morphants, NAD+ is not sufficient to improve NMJ morphology in dag1 morphants. Ubiquitous overexpression of Fkrp rescued the fkrp morphant phenotype but muscle-specific overexpression only improved myotendinous junction structure.
CONCLUSIONS
These data indicate that Fkrp plays an early and essential role in muscle, myotendinous junction, and neuromuscular junction development. These data also indicate that, at least in the zebrafish model, FKRP-associated dystroglycanopathy does not exactly phenocopy DG-deficiency. Paxillin overexpression improves muscle structure in dag1 morphants but not fkrp morphants. In contrast, NAD+ supplementation improves NMJ morphology in fkrp morphants but not dag1 morphants. Finally, these data show that muscle-specific expression of Fkrp is insufficient to rescue muscle development and homeostasis.
Topics: Animals; Animals, Genetically Modified; Disease Models, Animal; Dystroglycans; Glycosylation; Glycosyltransferases; Humans; Muscle Development; Muscular Dystrophy, Animal; Mutation; NAD; Neuromuscular Junction; Paxillin; Up-Regulation; Zebrafish; Zebrafish Proteins
PubMed: 31391079
DOI: 10.1186/s13395-019-0206-1