Brain metastases are a very common and serious complication of oncological diseases. Despite the vast progress in multimodality treatment, brain metastases significantly decrease the quality of life and prognosis of patients. Therefore, identifying new targets in the microenvironment of brain metastases is desirable. Fibroblast activation protein (FAP) is a transmembrane serine protease typically expressed in tumour-associated stromal cells. Due to its characteristic presence in the tumour microenvironment, FAP represents an attractive theranostic target in oncology. However, there is little information on FAP expression in brain metastases. In this study, we quantified FAP expression in samples of brain metastases of various primary origin and characterised FAP-expressing cells. We have shown that FAP expression is significantly higher in brain metastases in comparison to non-tumorous brain tissues, both at the protein and enzymatic activity levels. FAP immunopositivity was localised in regions rich in collagen and containing blood vessels. We have further shown that FAP is predominantly confined to stromal cells expressing markers typical of cancer-associated fibroblasts (CAFs). We have also observed FAP immunopositivity on tumour cells in a portion of brain metastases, mainly originating from melanoma, lung, breast, and renal cancer, and sarcoma. There were no significant differences in the quantity of FAP protein, enzymatic activity, and FAP+ stromal cells among brain metastasis samples of various origins, suggesting that there is no association of FAP expression and/or presence of FAP+ stromal cells with the histological type of brain metastases. In summary, we are the first to establish the expression of FAP and characterise FAP-expressing cells in the microenvironment of brain metastases. The frequent upregulation of FAP and its presence on both stromal and tumour cells support the use of FAP as a promising theranostic target in brain metastases.

• MeSH
• fibroblasty patologie   MeSH
• individualizovaná medicína MeSH
• karcinom z renálních buněk * patologie   MeSH
• kvalita života MeSH
• lidé MeSH
• membránové proteiny metabolismus   MeSH
• nádorové mikroprostředí MeSH
• nádory ledvin * patologie   MeSH
• nádory mozku * patologie   MeSH
• serinové endopeptidasy metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

Fibroblast activation protein (FAP) is a non-classical serine protease expressed predominantly in conditions accompanied by tissue remodeling, particularly cancer. Due to its plasma membrane localization, FAP represents a promising molecular target for tumor imaging and treatment. The unique enzymatic activity of FAP facilitates development of diagnostic and therapeutic tools based on molecular recognition of FAP by substrates and small-molecule inhibitors, in addition to conventional antibody-based strategies. In this review, we provide background on the pathophysiological role of FAP and discuss its potential for diagnostic and therapeutic applications. Furthermore, we present a detailed analysis of the structural patterns crucial for substrate and inhibitor recognition by the FAP active site and determinants of selectivity over the related proteases dipeptidyl peptidase IV and prolyl endopeptidase. We also review published data on targeting of the tumor microenvironment with FAP antibodies, FAP-targeted prodrugs, activity-based probes and small-molecule inhibitors. We describe use of a recently developed, selective FAP inhibitor with low-nanomolar potency in inhibitor-based targeting strategies including synthetic antibody mimetics based on hydrophilic polymers and inhibitor conjugates for PET imaging. In conclusion, recent advances in understanding of the molecular structure and function of FAP have significantly contributed to the development of several tools with potential for translation into clinical practice.

• MeSH
• dipeptidylpeptidasa 4 metabolismus   MeSH
• fibroblasty metabolismus   MeSH
• katalytická doména MeSH
• lidé MeSH
• membránové proteiny chemie   účinky léků   metabolismus   MeSH
• molekulární struktura MeSH
• nádorové mikroprostředí MeSH
• nádory diagnóza   metabolismus   terapie   MeSH
• prekurzory léčiv MeSH
• serinové endopeptidasy chemie   účinky léků   metabolismus   MeSH
• substrátová specifita MeSH
• želatinasy chemie   účinky léků   metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH

Fibroblast activation protein (FAP, seprase) is a serine protease with post-proline dipeptidyl peptidase and endopeptidase enzymatic activity. FAP is upregulated in several tumor types, while its expression in healthy adult tissues is scarce. FAP molecule itself and FAP+ stromal cells play an important although probably context-dependent and tumor type-specific pathogenetic role in tumor progression. We provide an overview of FAP expression under both physiological and pathological conditions with focus on human malignancies. We also review and critically analyze the results of studies which used various strategies for the therapeutic targeting of FAP including the use of low molecular weight inhibitors, FAP activated prodrugs, anti-FAP antibodies and their conjugates, FAP-CAR T cells, and FAP vaccines. A unique enzymatic activity and selective expression in tumor microenvironment make FAP a promising therapeutic target. A better understanding of its role in individual tumor types, careful selection of patients, and identification of suitable combinations with currently available anticancer treatments will be critical for a successful translation of preclinically tested approaches of FAP targeting into clinical setting.

• MeSH
• cílená molekulární terapie metody   MeSH
• inhibitory enzymů terapeutické užití   MeSH
• lidé MeSH
• membránové proteiny antagonisté a inhibitory   genetika   metabolismus   MeSH
• nádorové mikroprostředí účinky léků   genetika   MeSH
• nádory farmakoterapie   genetika   metabolismus   MeSH
• regulace genové exprese enzymů účinky léků   MeSH
• regulace genové exprese u nádorů účinky léků   MeSH
• serinové endopeptidasy genetika   metabolismus   MeSH
• želatinasy antagonisté a inhibitory   genetika   metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH

Proteases are directly involved in cancer pathogenesis. Expression of fibroblast activation protein (FAP) is upregulated in stromal fibroblasts in more than 90% of epithelial cancers and is associated with tumor progression. FAP expression is minimal or absent in most normal adult tissues, suggesting its promise as a target for the diagnosis or treatment of various cancers. Here, we report preparation of a polymer conjugate (an iBody) containing a FAP-specific inhibitor as the targeting ligand. The iBody inhibits both human and mouse FAP with low nanomolar inhibition constants but does not inhibit close FAP homologues dipeptidyl peptidase IV, dipeptidyl peptidase 9, and prolyl oligopeptidase. We demonstrate the applicability of this iBody for the isolation of FAP from cell lysates and blood serum as well as for its detection by ELISA, Western blot, flow cytometry, and confocal microscopy. Our results show the iBody is a useful tool for FAP targeting in vitro and potentially also for specific anticancer drug delivery.

• MeSH
• ELISA MeSH
• hmotnostní spektrometrie s elektrosprejovou ionizací MeSH
• konfokální mikroskopie MeSH
• lidé MeSH
• membránové proteiny antagonisté a inhibitory   chemie   MeSH
• myši MeSH
• nádorové buněčné linie MeSH
• polymery chemie   MeSH
• průtoková cytometrie MeSH
• serinové endopeptidasy chemie   MeSH
• western blotting MeSH
• želatinasy antagonisté a inhibitory   chemie   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Glioblastomas are deadly neoplasms resistant to current treatment modalities. Fibroblast activation protein (FAP) is a protease which is not expressed in most of the normal adult tissues but is characteristically present in the stroma of extracranial malignancies. FAP is considered a potential therapeutic target and is associated with a worse patient outcome in some cancers. The FAP localization in the glioma microenvironment and its relation to patient survival are unknown. By analyzing 56 gliomas and 15 non-tumorous brain samples, we demonstrate increased FAP expression in a subgroup of high-grade gliomas, in particular on the protein level. FAP expression was most elevated in the mesenchymal subtype of glioblastoma. It was neither associated with glioblastoma patient survival in our patient cohort nor in publicly available datasets. FAP was expressed in both transformed and stromal cells; the latter were frequently localized around dysplastic blood vessels and commonly expressed mesenchymal markers. In a mouse xenotransplantation model, FAP was expressed in glioma cells in a subgroup of tumors that typically did not express the astrocytic marker GFAP. Endogenous FAP was frequently upregulated and part of the FAP(+) host cells coexpressed the CXCR4 chemokine receptor. In summary, FAP is expressed by several constituents of the glioblastoma microenvironment, including stromal non-malignant mesenchymal cells recruited to and/or activated in response to glioma growth. The limited expression of FAP in healthy tissues together with its presence in both transformed and stromal cells suggests that FAP may be a candidate target for specific delivery of therapeutic agents in glioblastoma.

• MeSH
• apoptóza MeSH
• buňky stromatu metabolismus   patologie   MeSH
• dospělí MeSH
• fibroblasty metabolismus   patologie   MeSH
• glioblastom genetika   metabolismus   patologie   MeSH
• imunoenzymatické techniky MeSH
• kvantitativní polymerázová řetězová reakce MeSH
• lidé středního věku MeSH
• lidé MeSH
• membránové proteiny genetika   metabolismus   MeSH
• messenger RNA genetika   MeSH
• mezoderm metabolismus   patologie   MeSH
• míra přežití MeSH
• myši inbrední NOD MeSH
• myši MeSH
• nádorové biomarkery metabolismus   MeSH
• nádorové buňky kultivované MeSH
• následné studie MeSH
• polymerázová řetězová reakce s reverzní transkripcí MeSH
• prognóza MeSH
• proliferace buněk MeSH
• senioři MeSH
• serinové endopeptidasy genetika   metabolismus   MeSH
• staging nádorů MeSH
• studie případů a kontrol MeSH
• transformované buněčné linie metabolismus   patologie   MeSH
• western blotting MeSH
• xenogenní modely - testy protinádorové aktivity MeSH
• želatinasy genetika   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• myši MeSH
• senioři MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• srovnávací studie MeSH

Vertebrate primary cilium is a Hedgehog signaling center but the extent of its involvement in other signaling systems is less well understood. This report delineates a mechanism by which fibroblast growth factor (FGF) controls primary cilia. Employing proteomic approaches to characterize proteins associated with the FGF-receptor, FGFR3, we identified the serine/threonine kinase intestinal cell kinase (ICK) as an FGFR interactor. ICK is involved in ciliogenesis and participates in control of ciliary length. FGF signaling partially abolished ICK's kinase activity, through FGFR-mediated ICK phosphorylation at conserved residue Tyr15, which interfered with optimal ATP binding. Activation of the FGF signaling pathway affected both primary cilia length and function in a manner consistent with cilia effects caused by inhibition of ICK activity. Moreover, knockdown and knockout of ICK rescued the FGF-mediated effect on cilia. We provide conclusive evidence that FGF signaling controls cilia via interaction with ICK.

• MeSH
• buňky NIH 3T3 MeSH
• cilie metabolismus   MeSH
• CRISPR-Cas systémy MeSH
• fibroblastové růstové faktory metabolismus   MeSH
• fosforylace MeSH
• HEK293 buňky MeSH
• interakční proteinové domény a motivy MeSH
• lidé MeSH
• modely u zvířat MeSH
• myši knockoutované MeSH
• myši MeSH
• protein-serin-threoninkinasy genetika   metabolismus   MeSH
• proteiny hedgehog metabolismus   MeSH
• proteomika MeSH
• receptor fibroblastových růstových faktorů, typ 1 metabolismus   MeSH
• receptor fibroblastových růstových faktorů, typ 3 genetika   metabolismus   MeSH
• receptor fibroblastových růstových faktorů, typ 4 metabolismus   MeSH
• receptory fibroblastových růstových faktorů genetika   metabolismus   MeSH
• signální transdukce MeSH
• simulace molekulového dockingu MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH

OBJECTIVES: S100A4 is a calcium binding protein with regulatory functions in cell homeostasis, proliferation and differentiation that has been shown to promote cancer progression and metastasis. In the present study, we evaluated the role of S100A4 in fibroblast activation in systemic sclerosis (SSc). METHODS: The expression of S100A4 was analysed in human samples, murine models of SSc and in cultured fibroblasts by real-time PCR, immunohistochemistry and western blot. The functional role of S100A4 was evaluated using siRNA, overexpression, recombinant protein and S100A4 knockout (S100A4(-/-)) mice. Transforming growth factor β (TGF-β) signalling was assessed by reporter assays, staining for phosphorylated Smad2/3 and analyses of target genes. RESULTS: The expression of S100A4 was increased in SSc skin and in experimental fibrosis in a TGF-β/Smad-dependent manner. Overexpression of S100A4 or stimulation with recombinant S100A4 induced an activated phenotype in resting normal fibroblasts. In contrast, knockdown of S100A4 reduced the pro-fibrotic effects of TGF-β and decreased the release of collagen. S100A4(-/-) mice were protected from bleomycin-induced skin fibrosis with reduced dermal thickening, decreased hydroxyproline content and lower myofibroblast counts. Deficiency of S100A4 also ameliorated fibrosis in the tight-skin-1 (Tsk-1) mouse model. CONCLUSIONS: We characterised S100A4 as a downstream mediator of the stimulatory effects of TGF-β on fibroblasts in SSc. TGF-β induces the expression of S100A4 to stimulate the release of collagen in SSc fibroblasts and induce fibrosis. Since S100A4 is essentially required for the pro-fibrotic effects of TGF-β and neutralising antibodies against S100A4 are currently evaluated, S100A4 might be a candidate for novel antifibrotic therapies.

• MeSH
• dospělí MeSH
• fibroblasty metabolismus   MeSH
• kůže metabolismus   MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladý dospělý MeSH
• modely nemocí na zvířatech MeSH
• myši knockoutované MeSH
• myši MeSH
• protein Smad2 metabolismus   MeSH
• protein Smad3 metabolismus   MeSH
• proteiny S100 metabolismus   MeSH
• senioři MeSH
• systémová sklerodermie metabolismus   MeSH
• transformující růstový faktor beta metabolismus   MeSH
• zvířata MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• myši MeSH
• senioři MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Dipeptidyl peptidase-IV (DPP-IV) and fibroblast activation protein-α (FAP) are speculated to participate in the regulation of multiple biological processes, because of their unique enzymatic activity, as well as by non-hydrolytic molecular interactions. At present, the role of DPP-IV and FAP in the development and progression of various types of tumors, including glioblastoma, is intensively studied, and their functional crosstalk is hypothesized. In this article, we describe the correlative expression of DPP-IV and FAP mRNA in primary cell cultures derived from human glioblastoma and associated expression dynamics of both molecules in astrocytoma cell lines depending on culture conditions. Although the molecular mechanisms of DPP-IV and FAP co-regulations remain unclear, uncoupled expression of transgenic DPP-IV and the endogenous FAP suggests that it occurs rather at the transcriptional than at the posttranscriptional level. Understanding of the expressional and functional coordinations of DPP-IV and FAP may help clarify the mechanisms of biological roles of both molecules in transformed astrocytic cells.

• MeSH
• buněčná diferenciace MeSH
• buněčné extrakty chemie   MeSH
• buněčné kultury MeSH
• dipeptidylpeptidasa 4 genetika   metabolismus   MeSH
• enzymatické testy MeSH
• genetická transkripce MeSH
• lidé MeSH
• membránové proteiny genetika   metabolismus   MeSH
• messenger RNA genetika   metabolismus   MeSH
• neuroglie enzymologie   metabolismus   MeSH
• rekombinantní proteiny genetika   metabolismus   MeSH
• serinové endopeptidasy genetika   metabolismus   MeSH
• transformované buněčné linie MeSH
• želatinasy genetika   metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

The transcription program that is responsible for the pluripotency of human ESCs (hESCs) is believed to be comaintained by exogenous fibroblast growth factor-2 (FGF-2), which activates FGF receptors (FGFRs) and stimulates the mitogen-activated protein kinase (MAPK) pathway. However, the same pathway is stimulated by insulin receptors, insulin-like growth factor 1 receptors, and epidermal growth factor receptors. This mechanism is further complicated by intracrine FGF signals. Thus, the molecular mechanisms by which FGF-2 promotes the undifferentiated growth of hESCs are unclear. Here we show that, in undifferentiated hESCs, exogenous FGF-2 stimulated the expression of stem cell genes while suppressing cell death and apoptosis genes. Inhibition of autocrine FGF signaling caused upregulation of differentiation-related genes and downregulation of stem cell genes. Thus, exogenous FGF-2 reinforced the pluripotency maintenance program of intracrine FGF-2 signaling. Consistent with this hypothesis, expression of endogenous FGF-2 decreased during hESC differentiation and FGF-2 knockdown-induced hESC differentiation. In addition, FGF-2 signaling via FGFR2 activated MAPK kinase/extracellular signal-regulated kinase and AKT kinases, protected hESC from stress-induced cell death, and increased hESC adhesion and cloning efficiency. This stimulation of self-renewal, cell survival, and adhesion by exogenous and endogenous FGF-2 may synergize to maintain the undifferentiated growth of hESCs.

• MeSH
• lidé MeSH
• Check Tag
• lidé MeSH

Fibroblast activation protein (FAP) has been extensively studied as a cancer biomarker for decades. Recently, small-molecule FAP inhibitors have been widely adopted as a targeting moiety of experimental theranostic radiotracers. Here we present a fast qPCR-based analytical method allowing FAP inhibition screening in a high-throughput regime. To identify clinically relevant compounds that might interfere with FAP-targeted approaches, we focused on a library of FDA-approved drugs. Using the DNA-linked Inhibitor Antibody Assay (DIANA), we tested a library of 2667 compounds within just a few hours and identified numerous FDA-approved drugs as novel FAP inhibitors. Among these, prodrugs of cephalosporin antibiotics and reverse transcriptase inhibitors, along with one elastase inhibitor, were the most potent FAP inhibitors in our dataset. In addition, by employing FAP DIANA in the quantification mode, we were able to determine FAP concentrations in human plasma samples. Together, our work expands the repertoire of FAP inhibitors, analyzes the potential interference of co-administered drugs with FAP-targeting strategies, and presents a sensitive and low-consumption ELISA alternative for FAP quantification with a detection limit of 50 pg/ml.

• MeSH
• cefalosporiny chemie   farmakologie   MeSH
• endopeptidasy * metabolismus   MeSH
• knihovny malých molekul farmakologie   chemie   MeSH
• lidé MeSH
• membránové proteiny * antagonisté a inhibitory   metabolismus   MeSH
• molekulární struktura MeSH
• rychlé screeningové testy * MeSH
• schvalování léčiv MeSH
• serinové endopeptidasy * metabolismus   MeSH
• Úřad Spojených států pro potraviny a léky MeSH
• vztah mezi dávkou a účinkem léčiva MeSH
• vztahy mezi strukturou a aktivitou MeSH
• želatinasy * antagonisté a inhibitory   metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Geografické názvy
• Spojené státy americké MeSH