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Results for “Fibroblast activation protein”

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At least 19 recordsLinked to original sources
PubMed2026

Transcriptomic profiling across stages of non-muscle-invasive bladder cancer identifies fibroblast activation protein-alpha as a stromal biomarker associated with progression.

BACKGROUND: T1 non-muscle-invasive bladder cancer (NMIBC) represents a biologically aggressive subgroup with substantial heterogeneity in recurrence and progression risk. Current clinicopathological risk stratification tools lack sufficient precision to identify patients at the highest risk of progression to muscle-invasive bladder cancer (MIBC). OBJECTIVE: To characterize transcriptomic differences between T1 and&#x2009;<&#x2009;T1 (Ta/Tis) NMIBC and to explore the association of fibroblast activation protein-&#x3b1; (FAP) gene expression with disease progression. METHODS: Transcriptomic profiling was performed on formalin-fixed paraffin-embedded (FFPE) tumor tissue from 66 patients with primary, treatment-na&#xef;ve NMIBC and 5 patients with T2 disease (included for exploratory comparisons). Analyses included differential gene expression, gene set enrichment analysis (GSEA), molecular subtyping, immune cell deconvolution, and evaluation of FAP expression in relation to recurrence and progression. External validation of FAP was conducted in three independent NMIBC cohorts. RESULTS: T1 tumors demonstrated a distinct transcriptomic profile compared with&#x2009;<&#x2009;T1 tumors, characterized by enrichment of cell cycle-related and metabolic pathways and a higher prevalence of aggressive molecular subtypes. Despite these molecular differences, no statistically significant differences in recurrence-free, progression-free, cancer-specific, and overall survival were observed, likely reflecting limited event numbers. Among recurrent tumors, early recurrences (&#x2264;&#x2009;24&#xa0;months) were associated with epithelial-mesenchymal transition signatures. FAP expression increased with tumor stage (p&#x2009;=&#x2009;0.0005) and was associated with progression (p&#x2009;=&#x2009;0.002) and mortality (p&#x2009;=&#x2009;0.01). Patients with tumors in the highest quartile of FAP expression had worse progression-free survival. This association was consistently observed in three external NMIBC cohorts. CONCLUSIONS: T1 NMIBC exhibits distinct transcriptomic features suggestive of increased biological aggressiveness. Elevated FAP expression is reproducibly associated with progression risk across multiple cohorts, supporting its potential role as a biomarker of aggressive disease. Given the limited number of progression events, these findings should be considered hypothesis-generating and warrant prospective validation before clinical implementation.

Humans↗
PubMed1978

Activation of mammalian cyclic AMP phosphodiesterases by trypsin.

BHK fibroblasts contain two forms of cyclic AMP phosphodiesterase 3':5'-cyclic nucleotide 5'-nucleotidohydrolase EC 3.1.4.17) as analyzed by linear sucrose gradient fractionation; a 3.6-S form (peak I) and a 6.7-S form (peak II). Peak I is specific for cyclic AMP as substrate and displays Michaelis-Menten kinetics with an apparent Km of 2--3 micrometer. Peak II hydrolyzes cyclic GMP and displays anomalous kinetics for cyclic AMP hydrolysis. The activity of isolated peak II for cyclic AMP is increased by storage at 4 degrees C, treatment with trypsin, or treatment with rat brain and BHK fibroblast activator proteins. The activity of isolated peak I is unaffected by these conditions. Linear sucrose gradient fractionation demonstrates that activation of peak II by trypsin leads to the formation of a 3.6-S cyclic AMP-specific enzyme form, possibly peak I. In contrast to BHK fibroblasts (and most other mammalian tissues), rat uterus contains only one form of cyclic nucleotide phosphodiesterase on linear sucrose gradients, a 7-S form capable of hydrolyzing both cyclic AMP and cyclic GMP. Treatment of rat uterine supernatant with trypsin leads to the appearance of a 4-S, cyclic AMP-specific form with properties similar to that of BHK peak I. These data suggest that the kinetically complex, higher molecular weight cyclic nucleotide phosphodiesterases may consist of more than one catalytically active site and that multiple forms of the enzyme arise through dissociative mechanisms, possibly as a means of in vivo regulation.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed2026

FAP+ pericyte-like cells promote monocyte differentiation into tumor-associated macrophages in glioblastoma.

Glioblastoma (GBM) is a highly aggressive primary brain tumor characterized by profound immunosuppression that facilitates tumor progression and promotes therapeutic resistance. Fibroblast activation protein (FAP), a recognized theranostic target in multiple cancers, is upregulated in GBM and predominantly expressed by pericyte-like stromal cells. Here we identify a role for FAP&#x207a; pericyte-like cells in shaping the GBM immune microenvironment through monocyte recruitment and differentiation. Analysis of The Cancer Genome Atlas (TCGA) datasets, supported by reverse-transcription quantitative PCR and immunohistochemistry, revealed that elevated FAP expression-serving as a proxy for the abundance of FAP&#x207a; pericyte-like cells-is associated with an immune-enriched tumor microenvironment characterized by higher macrophage abundance and elevated expression of M2 polarization markers. Spatial analyses, including immunofluorescence and spatial transcriptomics, demonstrated that immunosuppressive macrophages preferentially localize in proximity to FAP&#x207a; pericytes. Single-cell RNA sequencing identified these FAP&#x207a; cells as a distinct perivascular stromal subset with a unique expression pattern of extracellular matrix components and cytokines, including CCL2 and CSF1, with corresponding receptors expressed on myeloid cells. Functional assays using patient-derived FAP&#x207a; pericyte-like cells confirmed their ability to attract monocytes via soluble mediators and to promote their differentiation and polarization into tumor-associated macrophages with immunoregulatory features, partly mediated by the CSF1-CSF1R axis. Orthotopic co-implantation experiments in mice further supported their capacity to enhance myeloid infiltration in vivo. Consistent with these biological effects, a transcriptional signature characteristic of FAP&#x207a; pericytes correlated with worse overall survival in patients with GBM. Together, these findings position FAP&#x207a; pericyte-like cells as modulators of the GBM immune landscape, fostering a tumor-permissive niche by promoting the differentiation of circulating monocytes into immunoregulatory macrophages. Targeting this stromal population may offer new therapeutic avenues to reprogram tumor-associated immune responses in GBM.

Journal Article↗
PubMed2026

Elevated Triggering Receptor Expressed on Myeloid Cells 2 Expression in Tumor-Associated Macrophages Suppresses Cytotoxic T Cell Infiltration and Facilitates Immune Escape in Colorectal Cancer.

BACKGROUND & AIMS: Emerging evidence supports a crucial role for tumor-associated macrophages in shaping the immunosuppressive tumor microenvironment. Furthermore, research has identified that the triggering receptor expressed on myeloid cells 2 has immunomodulatory functions. The present investigated the potential effect of triggering receptor expressed on myeloid cells 2 expression in tumor-associated macrophages on facilitating immune evasion in colorectal cancer. METHODS: Immunohistochemical analysis of clinical specimens, complemented by extensive data mining from The Cancer Genome Atlas, revealed a significant upregulation of triggering receptor expressed on myeloid cells 2 in colorectal cancer-associated tumor-associated macrophages, with this upregulation exhibiting a correlation with poor patient prognosis. RESULTS: Mechanistically, triggering receptor expressed on myeloid cells 2+ tumor-associated macrophages were found to drive fibroblast activation through transforming growth factor-&#x3b2; signaling, inducing fibroblast-activated protein-positive cancer-associated fibroblasts that secrete collagen I/III to establish dense peritumoral barriers. Spatial profiling revealed that these fibrous structures physically impede CD8+ T-cell infiltration, restricting cytotoxic lymphocytes to stromal compartments. Intriguingly, triggering receptor expressed on myeloid cells 2 deficiency enhanced the secretion of matrix metalloproteinase 13 by macrophages, thereby promoting extracellular matrix degradation and improving T-cell penetration. In vivo, Trem2-knockout mice showed a reduction in tumor growth with enhanced intratumoral CD8+ T-cell infiltration compared with wild-type controls. CONCLUSIONS: Our findings establish triggering receptor expressed on myeloid cells 2+ tumor-associated macrophages as central regulators of stromal remodeling and suggest that therapeutic targeting of the triggering receptor expressed on myeloid cells 2/transforming growth factor-&#x3b2;/fibroblast-activated protein pathway may overcome immune resistance in patients with colorectal cancer.

Colorectal Neoplasms↗
PubMed1975

Effect of proteases on activation of resting chick embryo fibroblasts and on cell surface proteins.

The relationship between activation of resting chick embryo fibroblasts by proteases and proteolytic alteration of the cell surface has been investigated. Five different proteases were examined: trypsin, collagenase, plasmin, alpha-chymotrypsin, and thrombin. All of these proteases, when added to the culture medium at concentrations of 0.08-2.2 mug/ml, stimulated deoxyglucose uptake and induced cell division. The absolute levels of stimulation depended on the specific protease. Activation ranged from a doubling in cell number in 24 hr for trypsin and thrombin down to a 47% increase in cell number for alpha-chymotrypsin. Except in the case of thrombin, the stimulatory effects of these proteases correlated with breakdown of Z, a protein which is the major chick surface protein as revealed by lactoperoxidase-catalyzed iodination and which disappears upon transformation. In the case of thrombin, stimulatory concentrations brought about no detectable loss of surface components. Thus loss of Z is not a necessary condition for activation of chick fibroblasts; it may be a sufficient condition for activation of part of the cell population.

Cell Division↗
PubMed1992

Pituitary adenylate cyclase polypeptide (PACAP) stimulates cyclic AMP formation in pituitary fibroblasts and 3T3 tumor fibroblasts: lack of enhancement by protein kinase C activation.

A number of neuropeptides were shown to produce potent mitogenic effects on Swiss 3T3 fibroblasts by activating the phospholipase C pathway. Here we provide evidence for the activation by PACAP of the adenylate cyclase pathway in 3T3, as well as in non-tumoral pituitary fibroblasts, similarly to what was seen in pituitary endocrine cells. In these cells, PACAP triggered elevation of both intracellular and extracellular contents of cAMP and the effect was time- and dose-dependent, with half-maximal stimulations being induced with about 0.1 nM. Following activation of protein kinase C (PKC) by the phorbol ester phorbol 12-myristate 13-acetate (PMA), PACAP-induced cAMP production was amplified in pituitary endocrine cells, but was either unchanged or dampened in 3T3 and pituitary fibroblasts, respectively. Pretreatment of cells with pertussis toxin (PT) failed to change the effect of PMA on PACAP-stimulated adenylate cyclase activity, irrespective of the cell type being used. However, PT dramatically reduced the potentiation by PMA of cAMP production enhanced by forskolin in 3T3 cells. These results provide new evidence pointing to the presence in fibroblasts of receptors for PACAP, coupled to cAMP production, which may play a role in the modulation of the mitogenic signal. They also indicate that, compared with pituitary endocrine cells, PKC activation in fibroblasts differentially affected PACAP-induced cAMP formation and that these effects were unaltered upon inhibition by PT of Gi-like proteins.

1-Methyl-3-isobutylxanthine↗
PubMed1979

Intracellular collagen in recurrent ameloblastic fibroma.

Electron microscopic examination of tissue from a twice recurrent ameloblastic fibroma revealed the presence of intracellular collagen fibres in fibroblasts active in protein synthesis. The intracellular fibres were morphologically identical to collagen fibres located extracellularly. The literature on intracellular collagen in biological systems and pathological states has been reviewed, and attention is focussed on collagen phagocytosis and degradation by fibroblasts which are currently considered to represent the basis of connective tissue remodelling and turnover.

Ameloblasts↗
PubMed1978

Plasma membrane protein kinase activity in normal and Rous sarcoma virus-transformed chick embryo fibroblasts.

A preliminary study has been carried out to investigate the effect of Rous sarcoma virus transformation on plasma membrane protein kinase activity in chick embryo fibroblasts. Enzyme activity was measured using an in vitro phosphorylation method employing [gamma-32P]ATP with isolated plasma membranes serving as the source of both protein kinase and protein substrate. In general, the enzymatic properties observed were similar to those of other known protein kinases. However, for maximal activity a marked dependence on high Mg2+ concentrations was noted. Evidence was obtained which showed that cyclic nucleotide-dependent protein kinases were present in membranes from normal cells, but none could be measured in preparations from transformed cells. In addition, transformation appeared to result in a slight increase in basal plasma membrane protein kinase activity.

Adenosine Triphosphate↗
PubMed1992

[The regulation of protein kinase C activity in normal, immortalized and transformed rat fibroblasts].

In view of recent studies showing that cell proliferation of E1Aad5+c-Ha-ras-transformed fibroblasts cannot be regulated by growth factors and phorbol eaters in contrast to normal and E1Aad5-immortalized cell lines, the present work was undertaken to examine the role of protein kinase C (PKC) in the mitogenic signal transduction machinery in rat embryonal fibroblasts. It is shown that PKC is activated by acidic growth factor and phorbol esters in all the three cell lines. These findings suggest the existence of an additional, not associated with PKC-, growth-signaling pathway in E1Aad5-Ha-ras-transformed rat embryonal fibroblasts.

Animals↗
PubMed1975

[Histochemical study of fibroblasts and fibrous structures of the derma of rats in the process of postnatal development].

The histochemical data on the protein and carbohydrate exchange of fibroblasts in the period of intensive formation of fibres of the rats derm in the process of postnatal development are presented. The interrelationships between the size, the content of RNA, polysaccharides, proteins, the fibroblast enzyme activity and their fibreforming function is shown.

Age Factors↗
PubMed1979

Production of serum proteins in normal diploid fibroblast-hepatoma cell hybrids and in A9-normal liver cell hybrids.

Two series of interspecific hybrids have been generated between liver cells (which actively secrete several serum proteins) and fibroblasts (which do not). In each series, one of the parental cells was a normal diploid cell: mouse hepatoma cells were fused with normal diploid rat fibroblasts, and normal rat liver cells were fused with mouse fibroblasts of the permanent line A9. The production of albumin, alpha-fetoprotein (AFP) transferrin and the third component of complement (C3) was analysed in these hybrids. Most hepatoma cell hybrids exhibit extinction of albumin, AFP and (to a lesser extent) transferrin; they retain the capacity to secrete C3. Normal liver cell hybrids are also characterized by the absence of albumin and transferrin production and by retention of C3 secretion. These results, when compared to previous results obtained with hybrids derived exclusively from different differentiated cells of permanent and transformed lines show that the phenotype of such hybrids is not determined by the abnormal character per se of the aneuploid parental cells. Amongst the rat fibroblast-mouse hepatoma cell hybrids, a few clones retain the capacity to actively secrete mouse albumin, AFP and transferrin, without the concomitant production of the rat serum proteins. These hybrids have lost more rat (fibroblast) chromosomes than the other clones and also have an increased number of mouse (hepatoma) chromosomes. Thus, their phenotype must result from either the complete loss of 'extinguisher' chromosomes, or gene dosage effects. The significance of the lack of rat serum protein production is also discussed, and it is suggested that retention, without concomitant activation, could be explained in terms of diffusible regulators and heritable differences in chromatin conformation.

Animals↗
PubMedDate not supplied

Phosphorylation and protein kinase activities of chromosomal non histone proteins from chick embryo fibroblasts.

Confluent chick embryo fibroblasts were cultured in vitro in (i) medium which prevented the cells from dividing, (ii) medium which stimulated the cells to divide synchronously, (iii) medium without lysine in which the cells were blocked in G1. Chromosomal non histone proteins (NHP) were extracted from cells pulse labelled with 32P phosphate, and the radioactivity analyzed by acrylamide gel electrophoresis. Several radioactive peaks were found all along the gel in the NHP from confluent and stimulated cells. The highest phosphorylation was found in the fast moving proteins, but the stimulation of the cells increases the phosphorylation of the slower moving proteins. In the NHP from cells cultured in the medium without lysine only the slow migrating proteins were phosphorylated. NHP were extracted from unlabelled cell cultures in the three different media, incubated with [gamma-32P] ATP and analyzed by acrylamide gel electrophoresis. Highly labelled peaks were observed in the fast moving proteins from stimulated cells and from cells cultured in a medium deprived from lysine. By comparing in vivo and in vitro phosphorylation, it can be concluded that in confluent cells the turnover of bound phosphate is slow. In stimulated cells there is a fast turnover of the phosphate bound to fast turnover of the phosphate bound to a small group of fast migrating proteins and very little turnover of the phosphate bound to slow migrating proteins. The cells were incubated with labelled lysine and NHP analyzed by gel electrophoresis. The radioactivity of individual NHP varied with the culture conditions, but in all cases, there was little radioactivity in the fast moving proteins. The phosphate groups submitted to a fast turnover are bound to stable proteins. Phosvitin and casein kinase activities were measured in the NHP fractions. Nine-ten peaks of activities were observed with each substrate. Some variations were observed which apparently correlate with the culture conditions.

Adenosine Triphosphate↗
PubMed1977

Enhanced UDP-galactose:glycoprotein galactosyl transferase activity in cultivated skin fibroblasts from patients with cystic fibrosis and its possible relationship to the pathogenesis of the disease.

Homogenates of cultivated skin fibroblasts derived from patients with cystic fibrosis had a higher level of UDP-galactose:ovalbumin galactosyl transferase activity compared to fibroblasts derived from control subjects. The activity in control subjects was 1.82 +/- 0.43 nmol galactose transferred/hr/mg protein, whereas the activity in fibroblasts of patients was 2.95 +/- 0.77. The difference was significant at P less than 0.01. Activity in the fibroblasts of obligate heterozygotes was 2.15 +/- 0.60. The difference between the activities in fibroblasts of heterozygotes and patients was significant at P less than 0.05. The activity in control fibroblasts could be enhanced by basic polypeptides like polylysine, polyarginine, histone, and protamine but not by neutral or acidic polypeptides. Fibroblasts from patients released significantly higher amounts of a soluble form of the enzyme activity into the culture medium than control fibroblasts.

Cells, Cultured↗
PubMed1978

Inhibition of basal protein degradation in rat embryo fibroblasts by cycloheximide: correlation with activities of lysosomal proteases.

Rat embryo fibroblasts were grown in medium containing 14C-leucine and 3H-thymidine. After a 24-hour chase in nonlabeled medium, cultures were placed in either fresh growth medium or medium containing 10-20 microgram/ml cycloheximide. Cell monolayers were processed at daily intervals for three days. Four hours prior to processing, cultures were placed in fresh medium and the accumulation rate of trichloroacetic acid soluble 14C in the media assayed. Cycloheximide effects a progressive decrease in the fractional degradation rate of the labeled cell protein, primarily during the first 24 hours. The specific activities of cathepsin D, cathepsin B, and neutral protease correlate closely with the fractional degradation rate. Other lysosomal hydrolases show little change during this period. The activities of the lysosomal proteases approach a new steady state which is correlated with the new steady state level of protein synthesis. A model is proposed which relates the rate of protein breakdown in the cell to the level of protein synthesis. The data also suggests the possibility that subpopulations of high turnover and low turnover cells exist in these cultures.

Animals↗
PubMed1979

Pyruvate carboxylase and phosphoenolpyruvate carboxykinase activity in leukocytes and fibroblasts from a patient with pyruvate carboxylase deficiency.

Normal values are given for the activities of pyruvate carboxylase (E.C.6.4.1.1), mitochondrial phosphoenolpyruvate carboxykinase (E.C. 4.1.1.32, PEPCK), and citrate synthase (E.C. 4.1.3.7) in fibroblasts, lymphocytes, and leukocytes. Also given are values for these enzymes in the leukocytes and fibroblasts from a severely mentally and developmentally retarded patient with proximal renal tubular acidosis and hepatic, cerebral, and renal cortical pyruvate carboxylase deficiency. In normals, virtually all of the mitochondrial PEPCK and pyruvate carboxylase activity was present in the mononuclear leukocyte fraction of whole venous blood. Cellular fractionation studies with human lymphocytes and fibroblasts demonstrated that all of the PEPCK activity in these cells is mitochondrial. Normal values for pyruvate carboxylase in leukocytes were 0.092 (0.070--0.208) mU/mg protein (n=5), in lymphocytes 0.154 (0.092--0.262) mU/mg protein (n=5), and in fibroblasts 1.36 (0.778--2.19) mU/mg protein (n=5). The patient with hepatic, renal, and cerebral pyruvate carboxylase deficiency had no detectable activity (less than 0.009 mU/mg protein) in his leukocytes and 0.018 mU/mg protein in his fibroblasts. Data from an assay for pyruvate carboxylase activity in the patient's fibroblasts show that the activity observed is significant but very close to the lower limits of the assay. Values for PEPCK in normal lymphocytes were 1.42 (0.824--1.88) mU/mg protein (n=5), in leukocytes 1.68 (1.64--1.72) mU/mg protein (n=2), and in fibroblasts 5.49 (3.94--6.33) mU/mg protein (n=6).

Acidosis, Renal Tubular↗
PubMed1975

Interferon activity produced by translation of human interferon messenger RNA in cell-free ribosomal systems and in Xenopus oöcytes.

Translation of messenger RNA isolated from poly(rI)-poly(rC)-induced human fibroblasts in cell-free ribosomal systems and in Xenopus oocytes resulted in the production of biologically active proteins that had the properties of human fibroblast interferon. The translation in the oocytes was much more efficient, giving approximately 500 times higher titers of interferon activity than the cell-free systems. A control messenger RNA isolated from noninduced human fibroblasts, did not code for interferon synthesis in these systems. Both messenger RNA preparations stimulated [3H]amino-acid incorporation into trichloroacetic acid-insoluble material. The radioactive products and their immunoprecipitates were electrophoresed on polyacrylamide gels under denaturing conditions. The products resulting from the translation of the control (uninduced) messenger RNA in oocytes contained a major protein of approximately 45,000 molecular weight. The messenger RNA isolated from poly(rI)-poly(rC)-induced cells stimulated the synthesis of an additional 25,000 molecular weight protein that electrophoresed in the same position as human fibroblast interferon. These results suggest that human fibroblast interferon was synthesized by the translation of its messenger RNA in Xenopus oocytes and in cell-free ribosomal systems.

Animals↗