Fibroblast-activating Protein Research Articles

Carborane-FAPI conjugate: A potential FAP-targeted boron agent with improved boron content

Boron neutron capture therapy (BNCT) has received extensive attention as an advanced binary radiotherapy method. However, BNCT still faces poor selectivity of boron agent and is insufficient boron content in tumor tissues. To improve the tumor-targeted ability and boron content, this research aims to design, synthesize and preliminary evaluate a new borane agent Carborane-FAPI, which coupling the o-carborane to the compound skeleton of a mature fibroblast activating protein (FAP) inhibitor (FAPI). FAP is a tumor-associated antigen. FAP expressed lowly in normal organs and highly expressed in tumors, so it is a potential target for diagnosis and treatment. Boronophenylalanine (BPA) is the most widely investigated BNCT drug in present. Compared with BPA, the boron content of a single molecule is increased and drug targeting is enhanced. The results show that Carboaren-FAPI has low toxicity to normal cells, and selective enrichment in tumor tissues. It is a promising boron drug that has the potential to be used in BNCT.

Applications of FAPI PET/CT in the diagnosis and treatment of breast and the most common gynecologic malignancies: a literature review.

The fibroblast activating protein (FAP) is expressed by some fibroblasts found in healthy tissues. However, FAP is overexpressed in more than 90% of epithelial tumors, including breast and gynecological tumors. As a result, the FAP ligand could be used as a target for diagnosis and treatment purposes. Positron emission tomography/computed tomography (PET/CT) is a hybrid imaging technique commonly used to locate and assess the tumor's molecular and metabolic functions. PET imaging involves the injection of a radiotracer that tends to accumulate more in metabolically active lesions such as cancer. Several radiotracers have been developed to target FAP in PET/CT imaging, such as the fibroblast-activation protein inhibitor (FAPI). These tracers bind to FAP with high specificity and affinity, allowing for the non-invasive detection and quantification of FAP expression in tumors. In this review, we discussed the applications of FAPI PET/CT in the diagnosis and treatment of breast and the most common gynecologic malignancies. Radiolabeled FAPI can improve the detection, staging, and assessment of treatment response in breast and the most common gynecologic malignancies, but the problem with normal hormone-responsive organs remains insurmountable. Compared to the diagnostic applications of FAPI, further research is needed for future therapeutic applications.

FAPi-Based Agents in Thyroid Cancer: A New Step towards Diagnosis and Therapy? A Systematic Review of the Literature.

(1) Background: Thyroid cancer (TC) is often treated with surgery followed by iodine-131. Up to 50% of the instances of TC lose their avidity to 131I, becoming more aggressive. In this scenario, [18F]FDG PET/CT imaging is used for evaluating the widespread nature of the disease, despite its low sensitivity and a false negative rate of 8-21.1%. A novel class of PET agents targeting the fibroblast activation protein inhibitor (FAPi) has emerged, studied particularly for their potential application to theranostics. (2) Methods: A search of the literature was performed by two independent authors (P.G. and L.E.) using the PubMed, Scopus, Web of Science, Cochrane Library, and EMBASE databases. The following terms were used: "FAP" or "FAPi" or "Fibroblast activating protein" and "thyroid" or "thyroid cancer", in different combinations. The included papers were original articles, clinical studies, and case reports in the English language. No time limits were used. Editorials, conference papers, reviews, and preclinical studies were excluded. (3) Results: There were 31 papers that were selected. Some studies reported a low or absent FAPi uptake in TC lesions; others reported promising findings for the detection of metastases. (4) Conclusions: The preliminary results are encouraging. FAPI agents are an alternative to [18F]FDG and a promising theranostic tool. However, further studies with a larger population are needed.

Preclinical study and first-in-human imaging of [18F]FAP-2286, and comparison with 2-[18F]FDG PET/CT in various cancer patients.

Fibroblast-activated protein (FAP) is highly expressed in cancer-associated fibroblasts (CAFs) of many solid cancers, but low or absent in normal tissues. Our study aimed to develop a novel FAP-specific tracer, namely [18F]FAP-2286, and evaluated its performance in comparison with well-established agents such as [18F]FAPI-42 and [68Ga]Ga-FAP-2286 in preclinical research, as well as 2-[18F]FDG in pilot clinical study. [18F]FAP-2286 was manually synthesized in accordance with Good Manufacturing Practice (GMP). Subsequent investigations encompassed cell uptake, competitive binding affinity, internalization and efflux assays using HT-1080hFAP cell lines. PET imaging and biodistribution studies were conducted in HEK-293ThFAP, A549hFAP, HT-1080hFAP tumor-bearing mice as well as HEK-293T, A549 and HT-1080 control groups. Furthermore, clinical evaluation of [18F]FAP-2286 was performed in fifteen patients with various cancers compared to 2-[18F]FDG PET. The radiolabeling yield of [18F]FAP-2286 was 30.53 ± 5.20%, with a radiochemical purity exceeding 97%. In cell assays, [18F]FAP-2286 showed specific uptake, high internalization fraction and low cellular efflux. Rapid tumor uptake and satisfactory tumor retention was observed on micro-PET imaging and cancer patients. Meanwhile, the clinical research demonstrated that [18F]FAP-2286 may represent an alternative for low glucose-metabolism malignant tumors PET imaging such as gastric cancers. [18F]FAP-2286 showed superior imaging quality including rapid and high target uptake and satisfactory retention in both tumor-bearing mice and cancer patients. It may emerge as a promising candidate for early or delayed phase imaging and 2-[18F]FDG non-avid cancers PET scan.

Myofibroblastic cancer-associated fibroblast subtype heterogeneity in pancreatic cancer.

Pancreatic ductal adenocarcinoma (PDAC) has a fibrotic stroma that has both tumor-promoting and tumor-restraining properties. Different types of cancer-associated fibroblasts (CAFs) have been described. Here, we investigated whether CAFs within the same subtype exhibit heterogeneous functions. We evaluated the gene and protein expression differences in two myofibroblastic CAF (myCAF) lines using single-cell and bulk RNA-sequencing. We utilized proliferation and migration assays to determine the effect of different CAF lines on a tumor cell line. We found that myCAF lines express an activated stroma subtype gene signature, which is associated with a shorter survival in patients. Although both myCAF lines expressed α-smooth muscle actin (α-SMA), platelet-derived growth factor-α (PDGFR-α), fibroblast-activated protein (FAP), and vimentin, we observed heterogeneity between the two lines. Similarly, despite being consistent with myCAF gene expression overall, heterogeneity within specific genes was observed. We found that these differences extended to the functional level where the two myCAF lines had different effects on the same tumor cell line. The myCAF216 line, which had slightly increased inflammatory CAF-like gene expression and higher protein expression of α-SMA, PDGFR-α, and FAP was found to restrain migration of tumor cells. We found that two myCAF lines with globally similar expression characteristics had different effects on the same tumor cell line, one promoting and the other restraining migration. Our study highlights that there may be unappreciated heterogeneity within CAF subtypes. Further investigation and attention to specific genes or proteins that may drive this heterogeneity will be important.

Utilizing MRI, [18F]FDG-PET and [89Zr]Zr-DFO-28H1 FAP-PET tracer to assess inflammation and fibrogenesis in a reproducible lung injury rat model: a multimodal imaging study

ObjectiveAccurate imaging biomarkers that indicate disease progression at an early stage are highly important to enable timely mitigation of symptoms in progressive lung disease. In this context, reproducible experimental models and readouts are key. Here, we aim to show reproducibility of a lung injury rat model, by inducing disease and assessing disease progression by multi-modal non-invasive imaging techniques at two different research sites. Furthermore, we evaluated the potential of fibroblast activating protein (FAP) as an imaging biomarker in the early stage of lung fibrosis.MethodsAn initial lung injury rat model was set up at one research site (Lund University, Lund, Sweden) and repeated at a second site (Radboudumc, Nijmegen, The Netherlands). To induce lung injury, Sprague-Dawley rats received intratracheal instillation of bleomycin as one single dose (1,000 iU in 200 µL) or saline as control. Thereafter, longitudinal images were acquired to track inflammation in the lungs, at 1 and 2 weeks after the bleomycin challenge by magnetic resonance imaging (MRI) and [18F]FDG-PET. After the final [18F]FDG-PET scan, rats received an intravenous tracer [89Zr]Zr-DFO-28H1 (anti-FAP antibody) and were imaged at day 15, to track fibrogenesis. Upon termination, bronchoalveolar lavage (BAL) was performed to assess cell and protein concentration. Subsequently, the biodistribution of [89Zr]Zr-DFO-28H1 was measured ex vivo and the spatial distribution in lung tissue was studied by autoradiography. Lung sections were stained, and fibrosis assessed using the modified Ashcroft score.ResultsBleomycin-challenged rats showed body weight loss and increased numbers of immune cells and protein concentrations after BAL compared with control animals. The initiation and progression of the disease were reproduced at both research sites. Lung lesions in bleomycin-exposed rats were visualized by MRI and confirmed by histology. [18F]FDG uptake was higher in the lungs of bleomycin-challenged rats compared with the controls, similar to that observed in the Lund study. [89Zr]Zr-DFO-28H1 tracer uptake in the lung was increased in bleomycin-challenged rats compared with control rats (p = 0.03).ConclusionHere, we demonstrate a reproducible lung injury model and monitored disease progression using conventional imaging biomarkers MRI and [18F]FDG-PET. Furthermore, we showed the first proof-of-concept of FAP imaging. This reproducible and robust animal model and imaging experimental set-up allows for future research on new therapeutics or biomarkers in lung disease.

Unraveling the Role and Spatial Architecture of Cancer-Associated Fibroblasts in Classical Hodgkin Lymphoma

Introduction: Cancer-associated fibroblasts (CAFs) constitute an important stromal component of the tumor microenvironment (TME). They are a heterogeneous population of cells, which can modulate the immune system and have both pro-tumorigenic and anti-tumorigenic effects in a context-dependent manner. In solid tumors, the impact of CAFs in shaping the TME is well recognized, although challenges, including lack of specific CAF markers, still exist. In classical Hodgkin lymphoma (cHL), the role of CAFs has remained largely undefined. Here, we aimed to characterize distinct CAF subsets as well as their interactions with other TME cells and associate the findings with clinical characteristics and outcome of patients with previously untreated cHL. Methods: We used a tissue microarray (TMA) containing formalin-fixed paraffin-embedded samples from 115 diagnostic cHL tumors. The TMA was stained with a 7-plex immunohistochemistry panel to characterize CAFs [platelet-derived growth factor (PDGFR) -alpha and -beta, fibroblast-activating protein (FAP), secreted protein acidic and rich in cysteine (SPARC)], macrophages (CD68), Hodgkin-Reed Sternberg (HRS) cells (CD30), and leukocytes (CD45). Image processing and quality control were performed by combining Ilastik and CellProfiler softwares, and nuclei segmented by a pretrained deep learning segmentation model. Single cell features from the images were extracted using HistoCAT software. We utilized the Phenograph clustering algorithm for cell phenotyping and a permutation test by HistoCAT for neighborhood analysis. Results: We identified a total of 952,099 single cells, which were split into 25 distinct phenotype subsets by the Phenograph clustering spanning CAFs, macrophages, leukocytes, and HRS cells. CAFs were classified into seven distinct subsets based on the status of the different CAF markers. Median proportion of all CAFs was 28% (range 2-80%), the proportion being higher in the nodular sclerosis subtype compared to the others. In general, higher proportions of CAFs associated with favorable freedom from treatment failure (FFTF) independently of the subtype, age, and stage (P<0.01). On the contrary, a subcluster of CD45+ immune cells with strong FAP-positivity, which were characterized as macrophages, was enriched in other than nodular sclerosis subtype (P<0.001) and associated with worse FFTF independently of age, stage, and subtype (P=0.01). The neighborhood analysis allowed identification of colocalization and statistically significant interaction or avoidance between pairs of cell phenotypes. For instance, higher proportions of FAP+PDGFRalpha+ CAFs interacting with other cells predicted better FFTF (P<0.01), whereas interactions of FAP+ macrophages with other cells were associated with worse FFTF. Despite the positive impact of CAF proportions on cHL outcome, patients with CD30+ HRS cells surrounded by PDGFRbeta+ CAFs had worse FFTF (P<0.001). Conclusions: We have characterized distinct CAF subsets in cHL and demonstrate their favorable clinical impact on cHL outcome. We also identified a novel subset of FAP-positive macrophages, the proportions and interactions of which translated to poor outcome. Our data highlight that not only the cell proportions, but the cell-cell interactions and spatial context play a crucial role. Further validation of the findings is ongoing.

Abstract 13851: CAR-T Cells: A Potential Novel Strategy for Mitigating Fibrosis in Duchenne Muscular Dystrophy

Introduction: Chimeric Antigen T (CAR)-T cells have proven effective preclinically for mitigating cardiac fibrosis in hypertensive cardiomyopathy. Hypothesis: We assessed whether this approach could be applied to Duchenne Muscular Dystrophy (DMD) by targeting Fibroblast Activating Protein (FAP)-expressing activated fibroblasts in cardiac and skeletal muscle fibrosis. Methods: A protocol for the lymphodepletion conditioning of mice was developed to optimize the dosing of cyclophosphamide. Next, immune-magnetically selected T cells were retrovirally transduced to target FAP (FAP-CAR) and quality-controlled by co-culture killing assays using FAP-expressing HEK target cells. Finally, lymphodepleted D2. mdx mice were intravenously injected with 10 7 FAP-CAR T cells (n=9) or 10 7 GFP-T cells (n=9) or Bovine Serum Albumin (BSA, n=8). Cardiac and skeletal muscle end points were assessed 2 and 5 weeks after treatment. Results: In vitro , the engineered CAR-T cells expressed activation markers (CD69, PD-1) and released large amounts of granzyme, perforin and interferon γ upon exposure to FAP-expressing target cells. One IP injection of cyclophosphamide (3mg) 4 days before treatment was safe and induced a lymphodepletion which enabled robust in vivo expansion of FAP-CAR T cell assessed by flow cytometry in lymphoid organs and blood: 10 5 , 2.10 6 and 10 7 detected CAR-T cells at day 3, 5 and 7 post-injections, respectively. This was paralleled by a more than a 2-fold decrease in endogenous FAP expression in skeletal muscles, as assessed by PCR at day 5 post-injections, and measurable FAP-CAR levels in the spleen compared with GFP-T cell controls. In vivo , FAP-CAR T cells significantly improved LV function with an EF change from baseline (Mean±SEM) of 33.1% ± 6.7% in FAP-CAR vs. 3.7% ± 6.4% and -9.6% ± 7.9% in GFP-T and BSA ( p <0.037 and p <0.005, respectively) at 2 weeks. The benefit was maintained at 5 weeks post-treatment. Several markers of fibrosis, particularly collagens 1 and 3, were also down-regulated in heart and muscles. Conclusions: FAP-CAR-T cells might represent a new therapeutic option for mitigating fibrosis in DMD, likely in conjunction with approaches aimed at addressing the root cause of the disease through a re-expression of a functional dystrophin.

Elevated FAPI Activity in Ulcerative Fungal Esophagitis.

We report a case of ulcerative fungal esophagitis with elevated activity of 18F-FDG and 68Ga-FAPI (fibroblast-activating protein inhibitor). Our findings suggest that ulcerative fungal esophagitis should be considered in the differential diagnosis of cancer-like esophageal mass with increased 68Ga-FAPI uptake.

Fibroblast activating protein (FAP) is reduced in FGR in regions of the villous tree with disturbed differentiation of perivascular myofibroblasts

Fibroblast activating protein (FAP) is reduced in FGR in regions of the villous tree with disturbed differentiation of perivascular myofibroblasts

Nano-drug delivery system targeting FAP for the combined treatment of oral leukoplakia.

Oral leukoplakia (OLK) has received much attention due to its potential risk of malignant transformation. Studies have shown that when drug therapy is combined with photothermal therapy (PTT), not only can the cytotoxicity of the drug be enhanced, but also the heat energy can be used to kill the lesion cells, so we can combine drug therapy with PTT to enhance the therapeutic effect on OLK. However, with certain drawbacks due to its lack of targeting, fibroblast activating protein (FAP) has become an attractive target for OLK combination therapy. In this study, we used NGO-PEG loaded with FAP-targeting peptide (F-TP) and celecoxib (CXB) to construct a nano-drug delivery system CGPF for targeting OLK with high FAP expression and confirmed the biocompatibility and therapeutic efficacy of CGPF by in vitro and in vivo experiments. Overall, the novel nano-drug delivery system CGPF proposed in this study showed a very significant potential for the combination therapy of OLK.

Tumor-activated lymph node fibroblasts suppress T cell function in diffuse large B cell lymphoma.

Recent transcriptomic-based analysis of diffuse large B cell lymphoma (DLBCL) has highlighted the clinical relevance of LN fibroblast and tumor-infiltrating lymphocyte (TIL) signatures within the tumor microenvironment (TME). However, the immunomodulatory role of fibroblasts in lymphoma remains unclear. Here, by studying human and mouse DLBCL-LNs, we identified the presence of an aberrantly remodeled fibroblastic reticular cell (FRC) network expressing elevated fibroblast-activated protein (FAP). RNA-Seq analyses revealed that exposure to DLBCL reprogrammed key immunoregulatory pathways in FRCs, including a switch from homeostatic to inflammatory chemokine expression and elevated antigen-presentation molecules. Functional assays showed that DLBCL-activated FRCs (DLBCL-FRCs) hindered optimal TIL and chimeric antigen receptor (CAR) T cell migration. Moreover, DLBCL-FRCs inhibited CD8+ TIL cytotoxicity in an antigen-specific manner. Notably, the interrogation of patient LNs with imaging mass cytometry identified distinct environments differing in their CD8+ TIL-FRC composition and spatial organization that associated with survival outcomes. We further demonstrated the potential to target inhibitory FRCs to rejuvenate interacting TILs. Cotreating organotypic cultures with FAP-targeted immunostimulatory drugs and a bispecific antibody (glofitamab) augmented antilymphoma TIL cytotoxicity. Our study reveals an immunosuppressive role of FRCs in DLBCL, with implications for immune evasion, disease pathogenesis, and optimizing immunotherapy for patients.

Fibroblast activating protein promotes the proliferation, migration, and activation of fibroblasts in oral submucous fibrosis.

Fibroblast activating protein (FAP) is associated with various organ fibrosis. However, the expression and molecular function of FAP in oral submucous fibrosis (OSF) is still unclear. The high-performance liquid chromatography was used to detect the presence of alkaloids in areca nut extract (ANE). Real-time qPCR, Western blot, and Immunohistochemistry assay were used to analyze the expression of FAP mRNA or protein in OSF and normal oral tissue. A chi-squared test analyzed the relationship between FAP protein expression and clinicopathological data of OSF patients. CCK-8, Wound-healing, and Transwell migration assay were employed to assess the effect of the proliferation and migration ability of hOMF cells with FAP overexpression or knockdown. The expression level of a-SMA, FSP1, and P13K-Akt signaling pathways-related protein in hOMF cells transfected with FAP overexpression or knockdown plasmid was verified by western blot assay. The four specific areca alkaloids (Arecoline, Guvacine, Arecaidine, and Guvacoline) were successfully detected in the ANE. The viability of hOMF cells was significantly improved in the 50 μg/mL ANE group and was inhibited in the 5 and 50 mg/mL ANE groups. The expression of FAP was upregulated in OSF tissues, and hOMF cells treated with 50 μg/mL ANE and was related to pathology grade, clinical stage, and history of chewing betel nut. Additionally, FAP may promote the proliferation, migration, and activation of hOMF cells through the P13K-Akt signaling pathway. This study found that ANE had a bidirectional effect on the viability of hOMF cells, and the FAP gene was a potential therapeutic target in OSF.

Research progress of FAPI PET/CT in the diagnosis of malignant liver tumors

Malignant liver tumors have a high incidence and mortality rate. Therefore, it is of great significance to promptly learn about tumor advancement status through relevant examinations for patients' follow-up, diagnosis, and therapy as well as the improvement of the five-year survival rate. The primary lesions and intrahepatic metastases of malignant liver tumors have been better demonstrated in the clinical study with the use of various isotope-labeled fibroblast activating protein inhibitors because of their low uptake in liver tissues and high tumor/background ratio, which provides a new method for early diagnosis, precise staging, and radionuclide therapy. In light of this context, a review of the research progress of fibroblast-activating protein inhibitors for the diagnosis of liver malignant tumors is presented.

Diagnostic Performance of Positron Emission Tomography with Fibroblast-Activating Protein Inhibitors in Gastric Cancer: A Systematic Review and Meta-Analysis.

Various papers have introduced the use of positron emission tomography (PET) with [68Ga]Ga-radiolabeled fibroblast-activation protein inhibitor (FAPi) radiopharmaceuticals in different subtypes of gastric cancer (GC). Our aim was to assess the diagnostic performance of this novel molecular imaging technique in GC with a systematic review and meta-analysis. A straightforward literature search of papers concerning the diagnostic performance of FAP-targeted PET imaging was performed. Original articles evaluating this novel molecular imaging examination in both newly diagnosed GC patients and GC patients with disease relapse were included. The systematic review included nine original studies, and eight of them were also eligible for meta-analysis. The quantitative synthesis provided pooled detection rates of 95% and 97% for the assessment of primary tumor and distant metastases, respectively, and a pooled sensitivity and specificity of 74% and 89%, respectively, for regional lymph node metastases. Significant statistical heterogeneity among the included studies was found only in the analysis of the primary tumor detection rate (I2 = 64%). Conclusions: Beyond the limitations of this systematic review and meta-analysis (i.e., all the included studies were conducted in Asia, and using [18F]FDG PET/CT as a comparator of the index test), the quantitative data provided demonstrate the promising diagnostic performance of FAP-targeted PET imaging in GC. Nevertheless, more prospective multicentric studies are needed to confirm the excellent performances of FAP-targeted PET in this cluster of patients.

Noninvasive imaging of FAP expression using positron emission tomography: A comparative evaluation of a [18F]-labeled glycopeptide-containing FAPI with [18F]FAPI-42.

Research on fibroblast activating protein (FAP)-targeting inhibitor (FAPI) has become an important focus for cancer imaging and radiotherapy. Quinoline-based tracers [68Ga]FAPI-04 and [18F]FAPI-42 have been widely used for positron emission tomography (PET) imaging of most tumors. However, there exist some limitations of these tracers with high uptake in biliary duct system and unstable uptake in pancreas, unsuitable for abdominal tumors PET imaging. Here we developed a [18F]-labeled glycopeptide-containing FAPI tracer (named [18F]FAPT) for PET imaging of FAP in cancers. [18F]FAPT was synthesized manually and automatically. The competitive binding to FAP, cellular internalization, and efflux characteristics were examined in vitro using A549-FAP cells. Dynamic MicroPET and biodistribution studies of [18F]FAPT were then conducted in A549-FAP and U87MG xenograft tumor mouse models compared with [18F]FAPI-42. Five healthy volunteers and three patients with cancer underwent [18F]FAPT PET/CT. Preclinical and clinical studies showed specific binding of [18F]FAPT to FAP and favorable pharmacokinetic properties with better hydrophilicity, lower uptake in biliary duct system, higher tumor uptake and longer tumor retention compared with [18F]FAPI-42. The biodistribution of [18F]FAPT in healthy volunteers and patients with cancer displayed low uptake in most normal tissues except for pancreas, thyroid and salivary gland, which could contribute to high tumor-to-background ratios in most cancers. [18F]FAPT is better PET tracer than [18F]FAPI-42 for imaging of biliary duct system cancer, potentially providing a tool to examine FAP expression in most cancers with high tumor-to-background ratios.

Phase I study of MP0317, a FAP-dependent DARPin, for tumor-localized CD40 activation in patients with advanced solid tumors.

2584 Background: CD40 is a master switch for both innate and adaptive immune systems. The clinical development of CD40 agonists has been hampered by dose-limiting toxicity (DLT) due to systemic CD40 activation and peripheral target-mediated drug disposition (TMDD). MP0317 is a CD40-agonistic DARPin (designed ankyrin repeat protein), developed to reduce systemic toxicity. MP0317 is exclusively active in the presence of fibroblast activating protein (FAP) expressed by cancer associated fibroblasts in the tumor microenvironment. This allows reaching serum levels that overcome the TMDD and have the potential to deliver sustained and tumor-localized CD40 activation. Ongoing clinical testing aims at establishing its safety/tolerability profile, PK/PD characteristics, and a recommended dose for combination therapy. Methods: NCT05098405 is a Phase 1, multicenter, open label, dose escalation study followed by a safety expansion part in adult patients with advanced solid tumors. The dose escalation scheme uses an adaptive Bayesian logistic regression model with overdose control. Peripheral blood biomarkers are analyzed by immuno-assays and flow cytometry, and baseline and on-treatment tumor biopsies are characterized by RNA sequencing and immunofluorescence. Eligible patients are enrolled into 9 sequentially escalating dose cohorts of MP0317 (0.03-10 mg/kg), administered IV 3-weekly (Q3W) or 1-weekly (Q1W) until disease progression or unacceptable toxicity. Results: At submission, 23 patients across 6 cohorts completed the study, with no DLT observed. Patient enrolling in higher dose cohorts is ongoing. The most frequent AE was grade 2 infusion related reaction in 5 patients. The 23 patients received ≥2 (range 2-8) doses (range 0.03 – 3 mg/kg) of MP0317 across five Q3W and one Q1W cohorts and completed the 28-day DLT period. PK data confirmed all patients were exposed to MP0317 with broadly dose-dependent Cmax and no sign of accumulation. PD data was derived from patients dosed with 0.03 – 3 mg/kg. Soluble biomarkers (sFAP and sCD40) showed target engagement in periphery with signs of FAP saturation at ≥0.5 mg/kg. Colocalization of MP0317 with FAP and CD40 in the tumor was confirmed in 4 out of 8 evaluable paired tumor biopsies. Whole transcriptome and gene set enrichment analyses showed an upregulation of genes related to B-cell trafficking (CXCL3, CXCR5, CCR6, CCL20) upon treatment. Transient increase of IFNg-induced chemokines (CXCL9, CXCL10) was observed, whereas the pro-inflammatory cytokines (TNFa, IL-2, IL-6, IL-8) were not upregulated. Conclusions: Clinical data and the lack of pro-inflammatory circulating cytokines confirm MP0317 is safe and well-tolerated, while analysis of paired pre- and on-treatment tumor biopsies suggests early evidence of tumor-localized CD40 activation. The current data enables further evaluation in a combination setting. Clinical trial information: NCT05098405 .

Signal transducer and activator of transcription 3 and cancer associated fibroblasts jointly generate chemo-resistance and affect prognosis in epithelial ovarian cancer

Objective: To investigate the mechanism of signal transducer and activator of transcription 3 (STAT3) and cancer associated fibroblasts (CAF) jointly generate chemo-resistance in epithelial-ovarian cancer and their effect on prognosis. Methods: A total of 119 patients with high-grade ovarian serous cancer who received surgery in Cancer Hospital of Chinese Academy of Medical Sciences from September 2009 to October 2017 were collected. The clinico-pathological data and follow-up data were complete. Multivariate Cox regression model was used to analyze the prognostic factors. Ovarian cancer tissue chips of patients in our hospital were prepared. EnVision two-step method immunohistochemistry was used to detect the protein expression levels of STAT3, the specific markers of CAF activation, fibroblast activating protein (FAP), and type Ⅰ collagen (COL1A1) secreted by CAF. The relationship between the expression of STAT3, FAP, COL1A1 protein and drug resistance and prognosis of ovarian cancer patients was analyzed, and the correlation between the expression of three proteins was analyzed. These results were verified through the gene expression and prognostic information of human ovarian cancer tissues collected in the GSE26712 dataset of gene expression omnibus (GEO) database. Results: (1) Multivariate Cox regression model analysis showed that chemotherapy resistance was an independent risk factor for overall survival (OS) of ovarian cancer (P<0.001). (2) The expression levels of STAT3, FAP, and COL1A1 proteins in chemotherapy resistant patients were significantly higher than those in chemotherapy sensitive patients (all P<0.05). Patients with high expression of STAT3, FAP, and COL1A1 had significantly shorter OS than those with low expression (all P<0.05). According to the human ovarian cancer GSE26712 dataset of GEO database, patients with high expression of STAT3, FAP, and COL1A1 also showed shorter OS than patients with low expression (all P<0.05), the verification results were consistent with the detection results of ovarian cancer patients in our hospital. (3) Correlation analysis showed that the protein level of STAT3 was positively correlated with FAP and COL1A1 in our hospital's ovarian cancer tissue chips (r=0.47, P<0.001; r=0.30, P=0.006), the analysis of GEO database GSE26712 dataset showed that the expression of STAT3 gene and FAP, COL1A1 gene were also significantly positively correlated (r=0.31, P<0.001; r=0.52, P<0.001). Conclusion: STAT3 and CAF could promote chemotherapy resistance of ovarian cancer and lead to poor prognosis.

Evaluation of 18F-FAPI-04 Imaging in Assessing the Therapeutic Response of Rheumatoid Arthritis.

Fibroblast activating protein (FAP) is highly expressed in the synovial tissues of rheumatoid arthritis (RA) patients. The aim of this study was to determine the feasibility of PET imaging with an Al[18F] F-NOTA-labeled FAP inhibitor 04(18F-FAPI-04) for the evaluation of arthritic progression and therapeutic response in experimental arthritis. Fibroblast-like synoviocytes (FLSs) were obtained from patients with RA or osteoarthritis (OA), and the relationship between 18F-FAPI-04 uptake and the inflammatory activity of RA FLSs was investigated. Collagen-induce arthritis (CIA) mice models were established and treated with methotrexate (MTX) or etanercept (ETC). Then, PET imaging was performed 24h following 18F-FAPI-04 injection. The imaging results were compared by assessing macroscopic arthritis scores and histological staining. 18F-FAPI-04 uptake was obvious in RA FLSs that characterizing FAP activation. The higher the uptake of 18F-FAPI-04, the more severity of the inflammatory phenotype in RA FLS. Furthermore, the uptake of 18F-FAPI-04 in inflamed joints could be found even before the deformity of the parental joints could be observed by histological examination. Both MTX and ETC were effective in inhibiting the progression of arthritis in CIA mice was confirmed by macroscopic, histological, and radiographic pathology scores. Importantly, 18F-FAPI-04 uptake declined accordingly in CIA models following MTX and ETC treatment. These findings suggest that PET imaging of 18F-FAPI-04 can be used to monitor treatment response in RA, and is more sensitive in disease speculation than macroscopic arthritis scoring.

Novel dual CAFs and tumour cell targeting pH and ROS dual sensitive micelles for targeting delivery of paclitaxel to liver cancer

Tumour development is not only an independent event of genetic mutation and overgrowth of tumour cells but is the result of a synergistic interaction between a malignant tumour and its surrounding tumour stromal microenvironment. In this paper, we address the shortcomings of current tumour therapy by focussing on the tumour itself and the surrounding microenvironment to achieve a two-pronged targeting model. In this paper, a dual-targeting, pH/reactive oxygen species (ROS) sensitive nano-drug delivery system for tumour cells and CAFs was designed. A hyaluronic acid (HA) with CD44 receptor targeting on the surface of tumour cells was selected as the main carrier material, and a dipeptide Z-glycine-proline (ZGP) with specific targeting of fibroblast activating protein (FAP) on the surface of CAFs was modified on HA to achieve precise targeting of CAFs, open the physical barrier of tumour cells and improve the deep penetration effect of the tumour, while introducing thioketone bond and ketone condensation bond to take advantage of the highly reactive ROS and low pH microenvironment at the tumour site to achieve chemical bond breaking of nano micelles encapsulating paclitaxel (PTX), drug release, and thus drug aggregation at the tumour site and improved bioavailability of the drug.