Expression of fibroblast activation protein in human pancreatic adenocarcinoma and its clinicopathological significance

AIM: To examine fibroblast activation protein (FAP) expression in pancreatic ductal adenocarcinoma (PDAC) and to analyze its relationship with the clinicopathology of PDAC. METHODS: FAP expression was examined in 134 PDAC specimens by immunohistochemistry, and in four pancreatic cancer cell lines (SW1990, Miapaca-2, AsPC-1 and BxPC-3) by Western blotting assay. We also analyzed the association between FAP expression in PDAC cells and the clinicopathology of PDAC patients. RESULTS: The results showed that the FAP was expressed in both stromal fibroblast cells (98/134, 73.1%) and carcinoma cells (102/134, 76.1%). All 4 pancreatic cancer cell lines expressed FAP protein at different levels. Protein bands corresponding to the proteolytically active 170-kDa seprase dimer and its88-kDa seprase subunit were identif ied. Higher FAP expression in carcinoma cells was associated with tumor size (P < 0.001), fi brotic focus (P = 0.003), perineural invasion (P = 0.009) and worse clinical outcome (P = 0.0085). CONCLUSION: FAP is highly expressed in carcinoma cells and f ibroblasts in PDAC tissues, and its expression is associated with desmoplasia and worse prognosis.

Sustained small and intermediate size proteins expression in phorbol 12-myristate 13-acetate/ionomycine prolonged stimulated human fibroblasts

Objective:To compare the protein profile of culture supernatants in stimulated and unstimulated human fibroblasts to find some proteins indicating the presence of fibroblasts and their activation status.Methods:Dermal fibroblasts were stimulated with phorbol 12-myristate 13-acetate(PMA)/ionomycine for 72 h.MTT assay was done to determine cell viability and A/E fluorescent staining was used to evaluate the cell death pattern.Protein analysis was performed by gradient SDS polyacrylamide gel electrophoresis 8%–16%.Results:The supernatant of 24 h cultured both stimulated and unstimulated fibroblasts showed two bands in SDS-PAGE analysis with relative molecular weights of 8.59 and78.8 k Da.These bands density was decreased during the next 48 h in unstimulated cells while their expression was continued in PMA or PMA/ionomycine stimulated cells and a new 85.3 k Da band was appeared in unstimulated and 72 h PMA stimulated cells.Moreover,we found another seven small size(10–19.5 k Da) proteins in supernatants of48 h and 72 h unstimulated but not in PMA or PMA/Ionomycine stimulated fibroblasts.Most of these proteins expression were down regulated following fibroblast activation.This down-regulation is consistent with our finding that PMA or PMA/ionomycine stimulated cells exhibited a significant level of apoptosis cell death.Conclusions:Human fibroblasts produce some small to intermediate sized proteins with specific SDS-PAGE profile upon cell activation.Most of these proteins can be excreted in urine and can be immunogen theoretically so this data provided a reliable clue for fibrosis biomarker screening based on designation of an appropriated immunoassay.

The hypoxia-inducible factor-1α activates ectopic production of fibroblast growth factor 23 in tumor-induced osteomalacia

Tumor-induced osteomalacia （TIO） is a rare paraneoplastic syndrome in which ectopic production of fibroblast growth factor 23 （FGF23） by non-malignant mesenchymal tumors causes phosphate wasting and bone fractures. Recent studies have implicated the hypoxia-inducible factor-la （HIF-la） in other phosphate wasting disorders caused by elevated FGF23, including X-linked hypophosphatemic rickets and autosomal dominant hypophosphatemia. Here we provide evidence that HIF-la mediates aberrant FGF23 in TIO by transcriptionally activating its promoter. Immunohistochemical studies in phosphaturic mesenchymal tumors resected from patients with documented TIO showed that HIF-la and FGF23 were co-localized in spindle- shaped cells adjacent to blood vessels. Cultured tumor tissue produced high levels of intact FGF23 and demonstrated increased expression of HIF-la protein. Transfection of MC3T3-E1 and Saos-2 cells with a HIF-la expression construct induced the activity of a FGF23 reporter construct. Prior treatment of tumor organ cultures with HIF-la inhibitors decreased HIF-la and FGF23 protein accumulation and inhibited HIF-la-induced luciferase reporter activity in transfected cells. Chromatin immunoprecipitation assays confirmed binding to a HIF-la consensus sequence within the proximal FGF23 promoter, which was eliminated by treatment with a HIF-la inhibitor. These results show for the first time that HIF-la is a direct transcriptional activator of FGF23 and suggest that upregulation of HIF-la activity in TIO contributes to the aberrant FGF23 production in these patients.

Promising Effects of Zerumbone on the Regulation of Tumor-promoting Cytokines Induced by TNF-α-activated Fibroblasts

Inflammation plays an important role in the development of several cancers.Inflammatory cytokines,including tumor necrosis factor-α(TNF-α),are associated with the induction of inflammation.Chronic inflammation contributes to the progression of cancer through several mechanisms,including increased cytokine production and activation of transcription factors,such as nuclear factor-κB(NF-κB).Zerumbone(ZER),a component of subtropical ginger(Zingiber zerumbet Smith),seems to have anti-inflammatory,anti-cancer,and antioxidant activities.In this study,we aimed to explore the protective function and mechanisms of ZER against TNF-α-induced cancer-promoting cytokines.We found that the viability of stimulated human fibroblast cell lines was reduced after treatment with ZER(IC50=18µmol/L),compared to un-stimulated fibroblasts(IC50=40µmol/L).Besides,ZER inhibited mRNA expression and protein secretion of transforming growth factor-β(TGF-β),interleukin-33(IL-33),monocyte chemoattractant protein-1(MCP-1),and stromal cell-derived factor 1(SDF-1),which were produced by TNF-α-induced fibroblasts,as measured by quantitative real time-PCR(qRT-PCR)and ELISA assays.The mRNA expression levels of TGF-β,IL-33,SDF-1,and MCP-1 showed 8,5,2.5,and 4-fold reductions,respectively.Moreover,secretion of TGF-β,IL-33,SDF-1,and MCP-1 was reduced to 3.65±0.34 ng/mL,6.3±0.26,1703.6±295.2,and 5.02±0.18 pg/mL,respectively,compared to the untreated group.In addition,the conditioned media(CM)of TNF-α-stimulated fibroblasts increased the NF-κB expression in colorectal cancer cell lines(HCT-116 and Sw48),while in the vicinity of ZER,the expression of NF-κB was reversed.Considering the significant effects of ZER,this component can be used as an appropriate alternative herbal treatment for cancer-related chronic inflammation.

Cancer-associated fibroblasts of colorectal cancer: Translationalprospects in liquid biopsy and targeted therapy

Colorectal cancer (CRC) is a major global health concern. Accumulation of cancer-associated fibroblasts(CAFs) in CRC is associated with poor prognosis and disease recurrence. CAFs are the main cellular component ofthe tumor microenvironment. CAF-tumor cell interplay, which is facilitated by various secretomes, drives colorectalcarcinogenesis. The complexity of CAF populations contributes to the heterogeneity of CRC and influences patientsurvival and treatment response. Due to their significant roles in colorectal carcinogenesis, different clinicalapplications utilizing or targeting CAFs have been suggested. Circulating CAFs (cCAFs) which can be detected inblood samples, have been proposed to help in determining patient prognosis and enables the detection of cancerthrough liquid biopsy. Liquid biopsy is gaining traction as it is non-invasive, allows frequent and easy sampling, andshows concordance to tissue biopsy analysis. In addition, CAF-targeted therapy is currently being studied extensivelyto be used as one of the treatment avenues for CRC. Various mechanisms of CAF-targeted therapy have beenreported, including blocking the signaling pathways involving CAFs and cancer cells, thus abolishing the CAF-tumorcell crosstalk and subsequently hindering tumorigenesis. These translational applications of cCAFs and utilization ofCAFs as key targets for CRC therapy, although still in the early phases of development, will potentially improve CRCpatient management in the future.

CREG knockdown promotes NIH3T3 Fibroblasts Apoptosis via activating Cathepsin

Background The CREG is an important lysosomal protein involved in a variety of cellular functions including promoting cell differentiation,sustaining mature homeostasis, and antagonizing apoptosis.Deficiency of CREG in cell and tissue results in a pathologic apoptosis.The present study aimed to elucidate the mechanism of CREG regulation apoptosis.Methods We firstly generated stable NIH3T3 fibroblasts by transfection of pDS_shCREGs vectors.Furthermore, PI-Annexin V and TUNEL staining were used to identify that CREG knockdown promoted the cell apoptosis in NIH3T3 fibroblasts.Western blotting and immunofluorescence staining was used to identify the expression and localization of M6P/ IGF2R and cathepsin L in cytoplasm.Results pDS_shCREGs vector transfection produced an approximately 80%decrease in CREG levels both in the lysate and in the media.The expression and localization of M6P/IGF2R and cathepsin L in cytoplasma changed obviously associated with down-regulated of CREG.In addition,the retention and secretion of cathepsin L enhanced significantly.Using the specific inhibitor or siRNA to block cathepsin L activation attenuated the apoptosis mediated by CREG downregulation.Conclusions Our findings indicated that inhibition of CREG expression in NIH3T3 fibroblasts leads to impaired cathepsin L sorting function mediated by M6P/IGF2R and subsequently promotes pathological cell apoptosis.

EFFECTS OF TGF-β_1 ON THE EXPRESSION OF PLASMINOGEN ACTIVATOR INHIBITOR TYPE 1 IN CULTURED HUMAN RENAL INTERSTITIAL FIBROBLASTS

Objective To investigate the effects of transforming growth factor-β1 (TGF-β1 ) on the expression of plasminogen activator inhibitor type 1 (PAI-1 ) mRNA in renal interstitial fibrosis in vitro. Methods Human renal interstitial fibroblasts were isolated and cultured in vitro. The cells wers stimulated by TGF-β1 with different concentration (0 to 10ng/ml ) at different time (0 to 48h). The expression of PAI-1 mRNA was assayed by RT-PCR. Results TGF-β1, had dose-dependent and time-dependent effects on the expression of PAI-1 mRNA in renal interstitial fibroblasts. Conclusion TGF-β1 may partic- ipate in renal fibrosis with inducing the expression of PAI-1 mRNA in renal fibroblasts and affecting the synthesis and degradation of extracellular matrix (ECM).

Decellularized heart extracellular matrix alleviates activation of hiPSC-derived cardiac fibroblasts

Human induced pluripotent stem cell derived cardiac fibroblasts(hiPSC-CFs)play a critical role in modeling human cardiovascular diseases in vitro.However,current culture substrates used for hiPSC-CF differentiation and expansion,such as Matrigel and tissue culture plastic(TCPs),are tissue mismatched and may provide pathogenic cues.Here,we report that hiPSC-CFs differentiated on Matrigel and expanded on tissue culture plastic(M-TCP-iCFs)exhibit transcriptomic hallmarks of activated fibroblasts limiting their translational potential.To alleviate pathogenic activation of hiPSC-CFs,we utilized decellularized extracellular matrix derived from porcine heart extracellular matrix(HEM)to provide a biomimetic substrate for improving hiPSC-CF phenotypes.We show that hiPSC-CFs differentiated and expanded on HEM(HEM-iCFs)exhibited reduced expression of hallmark activated fibroblast markers versus M-TCP-iCFs while retaining their cardiac fibroblast phenotype.HEM-iCFs also maintained a reduction in expression of hallmark genes associated with pathogenic fibroblasts when seeded onto TCPs.Further,HEM-iCFs more homogenously integrated into an hiPSC-derived cardiac organoid model,resulting in improved cardiomyocyte sarcomere development.In conclusion,HEM provides an improved substrate for the differentiation and propagation of hiPSC-CFs for disease modeling.

Pancreatic cancer stroma:understanding biology leads to new therapeutic strategies

Pancreatic ductal adenocarcinoma(PDA)is among the deadliest cancers in the United States and in the world.Late diagnosis,early metastasis and lack of effective therapy are among the reasons why only 6%of patients diagnosed with PDA survive past 5 years.Despite development of targeted therapy against other cancers,little progression has been made in the treatment of PDA.Therefore,there is an urgent need for the development of new treatments.However,in order to proceed with treatments,the complicated biology of PDA needs to be understood first.Interestingly,majority of the tumor volume is not made of malignant epithelial cells but of stroma.In recent years,it has become evident that there is an important interaction between the stromal compartment and the less prevalent malignant cells,leading to cancer progression.The stroma not only serves as a growth promoting source of signals but it is also a physical barrier to drug delivery.Understanding the tumor-stroma signaling leading to development of desmoplastic reaction and tumor progression can lead to the development of therapies to decrease stromal activity and improve drug delivery.In this review,we focus on how the current understanding of biology of the pancreatic tumor microenvironment can be translated into the development of targeted therapy.

Establishment of FAP-overexpressing Cells for FAP-targeted Theranostics

Objective Fibroblast activation protein(FAP)has been widely studied and exploited for its clinical applications.One of the difficulties in interpreting reports of FAP-targeted theranostics is due to the lack of accurate controls,making the results less specific and less confirmative.This study aimed to establish a pair of cell lines,in which one highly expresses FAP(HT1080-hFAP)and the other has no detectable FAP(HT1080-vec)as control,to accurately evaluate the specificity of the FAP-targeted theranostics in vitro and in vivo.Methods The cell lines of the experimental group(HT1080-hFAP)and no-load group(HT1080-vec)were obtained by molecular construction of the recombinant plasmid pIRES-hFAP.The expression of hFAP in HT1080 cells was detected by PCR,Western blotting and flow cytometry.CCK-8,Matrigel transwell invasion assay,scratch test,flow cytometry and immunofluorescence were used to verify the physiological function of FAP.The activities of human dipeptidyl peptidase(DPP)and human endopeptidase(EP)were detected by ELISA in HT1080-hFAP cells.PET imaging was performed in bilateral tumor-bearing nude mice models to evaluate the specificity of FAP.Results RT-PCR and Western blotting demonstrated the mRNA and protein expression of hFAP in HT1080-hFAP cells but not in HT1080-vec cells.Flow cytometry confirmed that nearly 95%of the HT1080-hFAP cells were FAP positive.The engineered hFAP on HT1080 cells had its ability to retain enzymatic activities and a variety of biological functions,including internalization,proliferation-,migration-,and invasion-promoting activities.The HT1080-hFAP xenografted tumors in nude mice bound and took up^(68)GA-FAPI-04 with superior selectivity.High image contrast and tumor-organ ratio were obtained by PET imaging.The HT1080-hFAP tumor retained the radiotracer for at least 60 min.Conclusion This pair of HT1080 cell lines was successfully established,making it feasible for accurate evaluation and visualization of therapeutic and diagnostic agents targeting the hFAP.

Gold nanoparticles inhibit activation of cancer-associated fibroblasts by disrupting communication from tumor and microenvironmental cells

Cancer-associated fibroblasts(CAFs)are a major constituent of the tumor microenvironment(TME)and an important contributor to cancer progression and therapeutic resistance.Regulation of CAF activation is a promising strategy to influence cancer outcomes.Here,we report that ovarian cancer cells(OCs)and TME cells promote the activation of ovarian CAFs,whereas gold nanoparticles(GNPs)of 20 nm in diameter inhibit the activation,as demonstrated by the changes in cell morphology,migration,and molecular markers.GNPs exert the effect by altering the levels of multiple fibroblast activation or inactivation proteins,such as TGF-β1,PDGF,uPA and TSP1,secreted by OCs and TME cells.Thus,GNPs represent a potential tool to help understand multicellular communications existing in the TME as well as devise strategies to disrupt the communication.

Preclinical evaluation and pilot clinical study of [^(18)F]AlF-labeled FAPI-tracer for PET imaging of cancer associated fibroblasts

In recent years,fibroblast activation protein(FAP)has emerged as an attractive target for the diagnosis and radiotherapy of cancers using FAP-specific radioligands.Herein,we aimed to design a novel^(18)Flabeled FAP tracer([^(18)F]Al F-P-FAPI)for FAP imaging and evaluated its potential for clinical application.The[^(18)F]Al F-P-FAPI novel tracer was prepared in an automated manner within 42 min with a non-decay corrected radiochemical yield of 32±6%(n=8).Among A549-FAP cells,[^(18)F]Al F-P-FAPI demonstrated specific uptake,rapid internalization,and low cellular efflux.Compared to the patent tracer[^(18)F]FAPI-42,[^(18)F]Al F-P-FAPI exhibited lower levels of cellular efflux in the A549-FAP cells and higher stability in vivo.Micro-PET imaging in the A549-FAP tumor model indicated higher specific tumor uptake of[^(18)F]Al F-P-FAPI(7.0±1.0%ID/g)compared to patent tracers[^(18)F]FAPI-42(3.2±0.6%ID/g)and[68 Ga]Ga-FAPI-04(2.7±0.5%ID/g).Furthermore,in an initial diagnostic application in a patient with nasopharyngeal cancer,[^(18)F]Al F-P-FAPI and[^(18)F]FDG PET/CT showed comparable results for both primary tumors and lymph node metastases.These results suggest that[^(18)F]Al F-P-FAPI can be conveniently prepared,with promising characteristics in the preclinical evaluation.The feasibility of FAP imaging was demonstrated using PET studies.

Differentiation of NIH3T3 fibroblasts into adipocytes induced by peroxisome proliferator activated receptor γ2 expression

Objective To express mouse peroxisome proliferator activated receptor γ2 (mPPARγ2) in NIH3T3 fibroblasts mediated by the recombinant retrovirus and study its function.Methods The mPPARγ2 gene was subcloned into retrovirus vector pGCEN to generate the recombinant pGCEN/mPPARγ2. Then it was packaged into PA317 cells and selected with G418. Viral supernatants were harvested and then used to infect NIH3T3 fibroblasts. PPARγ activator 5,8,11,14-eicosatetraynoic acid (ETYA) was used to induce the mPPARγ2-expressing NIH3T3 cells into adipocyte differentiation.Results The recombinant retrovirus pGCEN/mPPARγ2 was constructed, and the higher titers of the viral supernatants were obtained. mPPARγ2 was expressed in NIH3T3 cells mediated by the recombinant retrovirus. Lipid accumulation obviously existed in these induced adipocytes which morphologically resembled mature adipocytes in vivo and expressed tissue specific adipocyte P2 (AP2) and Leptin genes.Conclusions An adipocyte differentiation model in vitro was successfully established. The work is the basis for further research on the molecular mechanism of adipocyte differentiation induced by PPARγ2.

Profibrotic role of the SOX9-MMP10-ECM biosynthesis axis in the tracheal fibrosis after injury and repair

Fibroblast activation and extracellular matrix(ECM)deposition play an important role in the tracheal abnormal repair process and fibrosis.As a transcription factor,SOX9 is involved in fibroblast activation and ECM deposition.However,the mechanism of how SOX9 regulates fibrosis after tracheal injury remains unclear.We investigated the role of SOX9 in TGF-b1-induced fibroblast activation and ECM deposition in rat tracheal fibroblast(RTF)cells.SOX9 overexpression adenovirus(Ad-SOX9)and siRNA were transfected into RTF cells.We found that SOX9 expression was up-regulated in RTF cells treated with TGF-b1.SOX9 overexpression activated fibroblasts and promoted ECM deposition.Silencing SOX9 inhibited cell proliferation,migration,and ECM deposition,induced G2 arrest,and increased apoptosis in RTF cells.RNA-seq and chromatin immunoprecipitation sequencing(ChIP-seq)assays identified MMP10,a matrix metalloproteinase involved in ECM deposition,as a direct target of SOX9,which promotes ECM degradation by increasing MMP10 expression through the Wnt/b-catenin signaling pathway.Furthermore,in vivo,SOX9 knockdown ameliorated granulation proliferation and tracheal fibrosis,as manifested by reduced tracheal stenosis.In conclusion,our findings indicate that SOX9 can drive fibroblast activation,cell proliferation,and apoptosis resistance in tracheal fibrosis via the Wnt/b-catenin signaling pathway.The SOX9eMMP10 eECM biosynthesis axis plays an important role in tracheal injury and repair.Targeting SOX9 and its downstream target MMP10 may represent a promising therapeutic approach for tracheal fibrosis.

The application of FAPI-targeted theranostics in pancreatic cancer:a narrative review

Pancreatic cancer is one of the most lethal malignancies in the world.Cancer-associated fibroblasts are one of the main components of tumor microenvironment in pancreatic cancer and play an essential role in tumor progression.Fibroblast activation protein that is expressed in specific subtypes of cancer-associated fibroblasts promotes tumor growth and is related to poor survival.Recent researches have preliminarily demonstrated a promising potential of radiopharmaceuticals targeting fibroblast activation protein in diagnosis and therapy of pancreatic cancer.This article comprehensively reviews the current development and clinical translation of fibroblast activation protein inhibitor-targeting radiopharmaceuticals in pancreatic cancer and provides significant perspectives for future investigations.

The FAPα-activated prodrug Z-GP-DAVLBH inhibits the growth and pulmonary metastasis of osteosarcoma cells by suppressing the AXL pathway

Osteosarcoma is a kind of bone tumor with highly proliferative and invasive properties,a high incidence of pulmonary metastasis and a poor prognosis.Chemotherapy is the mainstay of treatment for osteosarcoma.Currently,there are no molecular targeted drugs approved for osteosarcoma treatment,particularly effective drugs for osteosarcoma with pulmonary metastases.It has been reported that fibroblast activation protein alpha(FAPa)is upregulated in osteosarcoma and critically associated with osteosarcoma progression and metastasis,demonstrating that FAPa-targeted agents might be a promising therapeutic strategy for osteosarcoma.In the present study,we reported that the FAPa-activated vinblastine prodrug Z-GP-DAVLBH exhibited potent antitumor activities against FAPa-positive osteosarcoma cells in vitro and in vivo.Z-GP-DAVLBH inhibited the growth and induced the apoptosis of osteosarcoma cells.Importantly,it also decreased the migration and invasion capacities and reversed epithelial-mesenchymal transition(EMT)of osteosarcoma cells in vitro and suppressed pulmonary metastasis of osteosarcoma xenografts in vivo.Mechanistically,Z-GP-DAVLBH suppressed the AXL/AKT/GSK-3β/β-catenin pathway,leading to inhibition of the growth and metastatic spread of osteosarcoma cells.These findings demonstrate that Z-GP-DAVLBH is a promising agent for the treatment of FAPa-positive osteosarcoma,particularly osteosarcoma with pulmonary metastases.

Control of fibrosis and hypertrophic scar formation via glycolysis regulation with IR780

Background:Hypertrophic scars(HS)represent one of the most common clinical challenges due to unsatisfactory therapeutic results.HS formation is associated with the abnormal activation of fibroblasts and their excessive fibrotic behavior.Glycolysis dysregulation has been shown to participate in the incidence and progression of various fibrotic diseases and shows potential as a means of controlling HS formation.This work aimed to discuss the impact of augmented glycolysis on HS and to propose a method for controlling HS formation through glycolysis regulation.Methods:Here,augmented glycolysis was confirmed together with enhanced fibrotic activity in both HS fibroblasts(HFs)and HS tissues,and the suppression of glycolysis also attenuated fibroblast activation.We also introduced IR780,a heptamethine cyanine dye,to regulate glycolysis for the control of HS formation.Results:In vitro,cell studies indicated that IR780 significantly down-regulated glycolysis and suppressed the fibrotic activity of HFs.In vivo,the intralesional injection of IR780 into rabbit HS models led to the downregulation of glycolysis and the control of HS formation.Furthermore,IR780 accumulated preferentially in activated fibroblasts in both in vitro and in vivo studies,and thus specifically downregulated glycolysis and efficiently controlled fibrosis by targeting activated fibroblasts.Conclusions:This work identified a strategy for controlling fibrosis and HS formation from the perspective of glycolysis regulation with IR780 targeting of activated fibroblasts.