PDGFRα+ITGA11+ fibroblasts foster early-stage cancer lymphovascular invasion and lymphatic metastasis via ITGA11-SELE interplay.

Cancer-associated fibroblasts (CAFs) exhibit considerable heterogeneity in advanced cancers; however, the functional annotation and mechanism of CAFs in early-stage cancers remain elusive. Utilizing single-cell RNA sequencing and spatial transcriptomic, we identify a previously unknown PDGFRα+ITGA11+ CAF subset in early-stage bladder cancer (BCa). Multicenter clinical analysis of a 910-case cohort confirms that PDGFRα+ITGA11+ CAFs are associated with lymphovascular invasion (LVI) and poor prognosis in early-stage BCa. These CAFs facilitate LVI and lymph node (LN) metastasis in early-stage BCa, as evidenced in a PDGFRα+ITGA11+ CAFs-specific deficient mouse model. Mechanistically, PDGFRα+ITGA11+ CAFs promote lymphangiogenesis via recognizing ITGA11 surface receptor SELE on lymphatic endothelial cells to activate SRC-p-VEGFR3-MAPK pathway. Further, CHI3L1 from PDGFRα+ITGA11+ CAFs aligns the surrounding matrix to assist cancer cell intravasation, fostering early-stage BCa LVI and LN metastasis. Collectively, our study reveals the crucial role of PDGFRα+ITGA11+ CAFs in shaping metastatic landscape, informing the treatment of early-stage BCa LVI.

PDGFRA K385 mutants in myxoid glioneuronal tumors promote receptor dimerization and oncogenic signaling.

Myxoid glioneuronal tumors (MGNT) are low-grade glioneuronal neoplasms composed of oligodendrocyte-like cells in a mucin-rich stroma. These tumors feature a unique dinucleotide change at codon 385 in the platelet-derived growth factor receptor α (encoded by the PDGFRA gene), resulting in the substitution of lysine 385 into leucine or isoleucine. The functional consequences of these mutations remain largely unexplored. Here, we demonstrated their oncogenic potential in fibroblast and Ba/F3 transformation assays. We showed that the K385I and K385L mutants activate STAT and AKT signaling in the absence of ligand. Co-immunoprecipitations and BRET experiments suggested that the mutations stabilized the active dimeric conformation of the receptor, pointing to a new mechanism of oncogenic PDGF receptor activation. Furthermore, we evaluated the sensitivity of these mutants to three FDA-approved tyrosine kinase inhibitors: imatinib, dasatinib, and avapritinib, which effectively suppressed the constitutive activity of the mutant receptors. Finally, K385 substitution into another hydrophobic amino acid also activated the receptor. Interestingly, K385M was reported in a few cases of brain tumors but not in MGNT. Our results provide valuable insights into the molecular mechanism underlying the activation of PDGFRα by the K385I/L mutations, highlighting their potential as actionable targets in the treatment of myxoid glioneuronal tumors.

New 2-oxoindole derivatives as multiple PDGFRα/ß and VEGFR-2 tyrosine kinase inhibitors.

Two new series of N-aryl acetamides 6a-o and benzyloxy benzylidenes 9a-p based 2-oxoindole derivatives were designed as potent antiproliferative multiple kinase inhibitors. The results of one-dose NCI antiproliferative screening for compounds 6a-o and 9a-p elucidated that the most promising antiproliferative scaffolds were 6f and 9f, which underwent five-dose testing. Notably, the amido congener 6f was the most potent derivative towards pancreatic ductal adenocarcinoma MDA-PATC53 and PL45 cell lines (IC50 = 1.73 µM and 2.40 µM, respectively), and the benzyloxy derivative 9f was the next potent one with IC50 values of 2.85 µM and 2.96 µM, respectively. Both compounds 6f and 9f demonstrated a favorable safety profile when tested against normal prostate epithelial cells (RWPE-1). Additionally, compound 6f displayed exceptional selectivity as a multiple kinase inhibitor, particularly targeting PDGFRα, PDGFRß, and VEGFR-2 kinases, with IC50 values of 7.41 nM, 6.18 nM, and 7.49 nM, respectively. In contrast, the reference compound Sunitinib exhibited IC50 values of 43.88 nM, 2.13 nM, and 78.46 nM against the same kinases. The derivative 9f followed closely, with IC50 values of 9.9 nM, 6.62 nM, and 22.21 nM for the respective kinases. Both 6f and 9f disrupt the G2/M cell cycle transition by upregulating p21 and reducing CDK1 and cyclin B1 mRNA levels. The interplay between targeted kinases and these cell cycle regulators underpins the G2/M cell cycle arrest induced by our compounds. Also, compounds 6f and 9f fundamentally resulted in entering MDA-PATC53 cells into the early stage of apoptosis with good percentages compared to the positive control Sunitinib. The in silico molecular-docking outcomes of scaffolds 6a-o and 9a-p in VEGFR-2, PDGFRα, and PDGFRß active sites depicted their ability to adopt essential binding interactions like the reference Sunitinib. Our designed analogs, specifically 6f and 9f, possess promising antiproliferative and kinase inhibitory properties, making them potential candidates for further therapeutic development.

Avapritinib-based SAR studies unveil a binding pocket in KIT and PDGFRA.

Avapritinib is the only potent and selective inhibitor approved for the treatment of D842V-mutant gastrointestinal stromal tumors (GIST), the most common primary mutation of the platelet-derived growth factor receptor α (PDGFRA). The approval was based on the NAVIGATOR trial, which revealed overall response rates of more than 90%. Despite this transformational activity, patients eventually progress, mostly due to acquired resistance mutations or following discontinuation due to neuro-cognitive side effects. These patients have no therapeutic alternative and face a dismal prognosis. Notable, little is known about this drug's binding mode and its medicinal chemistry development, which is instrumental for the development of the next generation of drugs. Against this background, we solve the crystal structures of avapritinib in complex with wild-type and mutant PDGFRA and stem cell factor receptor (KIT), which provide evidence and understanding of inhibitor binding and lead to the identification of a sub-pocket (Gα-pocket). We utilize this information to design, synthesize and characterize avapritinib derivatives for the determination of key pharmacophoric features to overcome drug resistance and limit potential blood-brain barrier penetration.

Human intestinal organoid-derived PDGFRα + mesenchymal stroma enables proliferation and maintenance of LGR4 + epithelial stem cells.

BACKGROUND: Intestinal epithelial cells derived from human pluripotent stem cells (hPSCs) are generally maintained and cultured as organoids in vitro because they do not exhibit adhesion when cultured. However, the three-dimensional structure of organoids makes their use in regenerative medicine and drug discovery difficult. Mesenchymal stromal cells are found near intestinal stem cells in vivo and provide trophic factors to regulate stem cell maintenance and proliferation, such as BMP inhibitors, WNT, and R-spondin. In this study, we aimed to use mesenchymal stromal cells isolated from hPSC-derived intestinal organoids to establish an in vitro culture system that enables stable proliferation and maintenance of hPSC-derived intestinal epithelial cells in adhesion culture. METHODS: We established an isolation protocol for intestinal epithelial cells and mesenchymal stromal cells from hPSCs-derived intestinal organoids and a co-culture system for these cells. We then evaluated the intestinal epithelial cells and mesenchymal stromal cells' morphology, proliferative capacity, chromosomal stability, tumorigenicity, and gene expression profiles. We also evaluated the usefulness of the cells for pharmacokinetic and toxicity studies. RESULTS: The proliferating intestinal epithelial cells exhibited a columnar form, microvilli and glycocalyx formation, cell polarity, and expression of drug-metabolizing enzymes and transporters. The intestinal epithelial cells also showed barrier function, transporter activity, and drug-metabolizing capacity. Notably, small intestinal epithelial stem cells cannot be cultured in adherent culture without mesenchymal stromal cells and cannot replaced by other feeder cells. Organoid-derived mesenchymal stromal cells resemble the trophocytes essential for maintaining small intestinal epithelial stem cells and play a crucial role in adherent culture. CONCLUSIONS: The high proliferative expansion, productivity, and functionality of hPSC-derived intestinal epithelial cells may have potential applications in pharmacokinetic and toxicity studies and regenerative medicine.

Adeno-Associated Virus Type 5 Infection via PDGFRα Is Associated With Interstitial Lung Disease in Systemic Sclerosis and Generates Composite Peptides and Epitopes Recognized by the Agonistic Immunoglobulins Present in Patients With Systemic Sclerosis.

OBJECTIVE: The etiopathogenesis of systemic sclerosis (SSc) is unknown. Platelet-derived growth factor receptors (PDGFRs) are overexpressed in patients with SSc. Because PDGFRα is targeted by the adeno-associated virus type 5 (AAV5), we investigated whether AAV5 forms a complex with PDGFRα exposing epitopes that may induce the immune responses to the virus-PDGFRα complex. METHODS: The binding of monomeric human PDGFRα to the AAV5 capsid was analyzed by in silico molecular docking, surface plasmon resonance (SPR), and genome editing of the PDGFRα locus. AAV5 was detected in SSc lungs by in situ hybridization, immunohistochemistry, confocal microscopy, and molecular analysis of bronchoalveolar lavage (BAL) fluid. Immune responses to AAV5 and PDGFRα were evaluated by SPR using SSc monoclonal anti-PDGFRα antibodies and immunoaffinity-purified anti-PDGFRα antibodies from sera of patients with SSc. RESULTS: AAV5 was detected in the BAL fluid of 41 of 66 patients with SSc with interstitial lung disease (62.1%) and in 17 of 66 controls (25.75%) (P < 0.001). In SSc lungs, AAV5 localized in type II pneumocytes and in interstitial cells. A molecular complex formed of spatially contiguous epitopes of the AAV5 capsid and of PDGFRα was identified and characterized. In silico molecular docking analysis and binding to the agonistic anti-PDGFRα antibodies identified spatially contiguous epitopes derived from PDGFRα and AAV5 that interacted with SSc agonistic antibodies to PDGFRα. These peptides were also able to bind total IgG isolated from patients with SSc, not from healthy controls. CONCLUSION: These data link AVV5 with the immune reactivity to endogenous antigens in SSc and provide a novel element in the pathogenesis of SSc.

Autophagy supports PDGFRA-dependent brain tumor development by enhancing oncogenic signaling.

Autophagy is a conserved cellular degradation process. While autophagy-related proteins were shown to influence the signaling and trafficking of some receptor tyrosine kinases, the relevance of this during cancer development is unclear. Here, we identify a role for autophagy in regulating platelet-derived growth factor receptor alpha (PDGFRA) signaling and levels. We find that PDGFRA can be targeted for autophagic degradation through the activity of the autophagy cargo receptor p62. As a result, short-term autophagy inhibition leads to elevated levels of PDGFRA but an unexpected defect in PDGFA-mediated signaling due to perturbed receptor trafficking. Defective PDGFRA signaling led to its reduced levels during prolonged autophagy inhibition, suggesting a mechanism of adaptation. Importantly, PDGFA-driven gliomagenesis in mice was disrupted when autophagy was inhibited in a manner dependent on Pten status, thus highlighting a genotype-specific role for autophagy during tumorigenesis. In summary, our data provide a mechanism by which cells require autophagy to drive tumor formation.

G protein-coupled receptor 17 is regulated by WNT pathway during oligodendrocyte precursor cell differentiation.

G protein-coupled receptor 17 (GPR17) and the WNT pathway are critical players of oligodendrocyte (OL) differentiation acting as essential timers in developing brain to achieve fully-myelinating cells. However, whether and how these two systems are related to each other is still unknown. Of interest, both factors are dysregulated in developing and adult brain diseases, including white matter injury and cancer, making the understanding of their reciprocal interactions of potential importance for identifying new targets and strategies for myelin repair. Here, by a combined pharmacological and biotechnological approach, we examined regulatory mechanisms linking WNT signaling to GPR17 expression in OLs. We first analyzed the relative expression of mRNAs encoding for GPR17 and the T cell factor/Lymphoid enhancer-binding factor-1 (TCF/LEF) transcription factors of the canonical WNT/ß-CATENIN pathway, in PDGFRα+ and O4+ OLs during mouse post-natal development. In O4+ cells, Gpr17 mRNA level peaked at post-natal day 14 and then decreased concomitantly to the physiological uprise of WNT tone, as shown by increased Lef1 mRNA level. The link between WNT signaling and GPR17 expression was further reinforced in vitro in primary PDGFRα+ cells and in Oli-neu cells. High WNT tone impaired OL differentiation and drastically reduced GPR17 mRNA and protein levels. In Oli-neu cells, WNT/ß-CATENIN activation repressed Gpr17 promoter activity through both putative WNT response elements (WRE) and upregulation of the inhibitor of DNA-binding protein 2 (Id2). We conclude that the WNT pathway influences OL maturation by repressing GPR17, which could have implications in pathologies characterized by dysregulations of the OL lineage including multiple sclerosis and oligodendroglioma.

Morphological, immunohistochemical, and genetic analyses of epithelioid gastrointestinal stromal tumors.

Epithelioid gastrointestinal stromal tumors (GISTs) are rare and may be confused with other tumors with epithelioid morphology. Therefore, herein, we collected 12 epithelioid GIST samples and summarized their morphological and immunohistochemical characteristics. Through genetic testing, we explored the correlation between morphology and gene mutations. The results showed that eight tumors showed focal or diffuse myxoid stromal changes with less cohesively arranged rhabdoid tumor cells; among these, five showed platelet-derived growth factor receptor alpha gene (PDGFRA) mutations. Signet ring cells with sclerosing stroma and receptor tyrosine kinase type III gene (KIT) mutations were present in two cases, which might be a KIT mutation-associated growth pattern in epithelioid GISTs. Succinate dehydrogenase gene (SDH) mutations were detected in three cases. Simultaneously, PDGFRA mutations were detected in two cases, and the Kirsten rat sarcoma viral oncogene homolog gene (KRAS) mutation was detected in another case. SDH-subunit B (SDHB) expression was partially weak and strongly diffuse in two cases with concurrent PDGFRA and SDHD mutations, respectively. The coexistence of PDGFRA and SDHD mutations may have affected SDHB expression. Altogether, we concluded that PDGFRA mutations may play an important role in co-mutant GIST pathogenesis.

PDGFRA, KIT, and KDR Gene Amplification in Glioblastoma: Heterogeneity and Clinical Significance.

Glioblastoma (GBM) is the most frequent tumor of the central nervous system, and its heterogeneity is a challenge in treatment. This study examined tumoral heterogeneity involving PDGFRA, KIT, and KDR gene amplification (GA) in 4q12 and its association with clinical parameters. Specimens from 22 GBM cases with GA for the 4q12 amplicon detected by FISH were investigated for homogeneous or heterogeneous coamplification patterns, diffuse or focal distribution of cells harboring GA throughout tumor sections, and pattern of clustering of fluorescence signals. Sixteen cases had homogenously amplification for all three genes (45.5%), for PDGFRA and KDR (22.7%), or only for PDGFRA (4.6%); six cases had heterogeneous GA patterns, with subpopulations including GA for all three genes and for two genes - PDGFRA and KDR (13.6%), or GA for all three and for only one gene - PDGFRA (9.1%) or KIT (4.6%). In 6 tumors (27.3%), GA was observed in focal tumor areas, while in the remaining 16 tumors (72.7%) it was diffusely distributed throughout the pathological specimen. Amplification was universally expressed as double minutes and homogenously stained regions. Coamplification of all three genes PDGFRA, KIT, and KDR, age ≥ 60 years, and total tumor resection were statistically associated with poor prognosis. FISH proved effective for detailed interpretation of molecular heterogeneity. The study uncovered an even more diverse range of amplification patterns involving the 4q12 oncogenes in GBM than previously described, thus highlighting a complex tumoral heterogeneity to be considered when devising more effective therapies.

The expression of platelet-derived growth factor and its receptor in canine and feline meningiomas.

Feline meningiomas usually have benign biological behavior, while canine and human meningiomas are often classified as grade 2 or 3. Activation of the platelet-derived growth factor (PDGF) and its receptor signal pathway through PDGFß/Rß autocrine and paracrine is considered to play an important role in the tumor proliferation and malignant transformation of human meningiomas. However, there have been few studies about the expression of these molecules in canine meningiomas and no studies about their expression in feline meningiomas. We analyzed the PDGFα/Rα and PDGFß/Rß expression in canine and feline meningiomas by immunohistochemistry and western blotting. Immunohistochemically, most canine meningiomas showed the expression of PDGFα (42/44; 95.5%), PDGFRα (44/44; 100%) and PDGFRß (35/44; 79.5%), and a few showed the expression of PDGFß (8/44; 18.2%). In contrast, feline meningiomas were immunopositive for PDGFRα and PDGFRß in all cases (14/14; 100%), while no or a few cases expressed PDGFα (0/14; 0%) and PDGFß (2/14; 14.3%). Western blotting revealed specific bands for PDGFα, PDGFRα and PDGFRß, but not for PDGFß in a canine meningioma. In a feline meningioma, specific bands for PDGFRα and PDGFRß were detected, but not for PDGFα and PDGFß. These results suggested that canine meningiomas commonly express PDGFα/Rα, and thus autocrine or paracrine PDGFα/Rα signaling may be involved in their initiation and progression. Moreover, PDGF negativity may be related to benign biological behavior and a low histopathological grade in feline meningioma.

Cardiac Pericytes Acquire a Fibrogenic Phenotype and Contribute to Vascular Maturation After Myocardial Infarction.

BACKGROUND: Pericytes have been implicated in tissue repair, remodeling, and fibrosis. Although the mammalian heart contains abundant pericytes, their fate and involvement in myocardial disease remains unknown. METHODS: We used NG2Dsred;PDGFRαEGFP pericyte:fibroblast dual reporter mice and inducible NG2CreER mice to study the fate and phenotypic modulation of pericytes in myocardial infarction. The transcriptomic profile of pericyte-derived cells was studied using polymerase chain reaction arrays and single-cell RNA sequencing. The role of transforming growth factor-ß (TGF-ß) signaling in regulation of pericyte phenotype was investigated in vivo using pericyte-specific TGF-ß receptor 2 knockout mice and in vitro using cultured human placental pericytes. RESULTS: In normal hearts, neuron/glial antigen 2 (NG2) and platelet-derived growth factor receptor α (PDGFRα) identified distinct nonoverlapping populations of pericytes and fibroblasts, respectively. After infarction, a population of cells expressing both pericyte and fibroblast markers emerged. Lineage tracing demonstrated that in the infarcted region, a subpopulation of pericytes exhibited transient expression of fibroblast markers. Pericyte-derived cells accounted for ~4% of PDGFRα+ infarct fibroblasts during the proliferative phase of repair. Pericyte-derived fibroblasts were overactive, expressing higher levels of extracellular matrix genes, integrins, matricellular proteins, and growth factors, when compared with fibroblasts from other cellular sources. Another subset of pericytes contributed to infarct angiogenesis by forming a mural cell coat, stabilizing infarct neovessels. Single-cell RNA sequencing showed that NG2 lineage cells diversify after infarction and exhibit increased expression of matrix genes, and a cluster with high expression of fibroblast identity markers emerges. Trajectory analysis suggested that diversification of infarct pericytes may be driven by proliferating cells. In vitro and in vivo studies identified TGF-ß as a potentially causative mediator in fibrogenic activation of infarct pericytes. However, pericyte-specific TGF-ß receptor 2 disruption had no significant effects on infarct myofibroblast infiltration and collagen deposition. Pericyte-specific TGF-ß signaling was involved in vascular maturation, mediating formation of a mural cell coat investing infarct neovessels and protecting from dilative remodeling. CONCLUSIONS: In the healing infarct, cardiac pericytes upregulate expression of fibrosis-associated genes, exhibiting matrix-synthetic and matrix-remodeling profiles. A fraction of infarct pericytes exhibits expression of fibroblast identity markers. Pericyte-specific TGF-ß signaling plays a central role in maturation of the infarct vasculature and protects from adverse dilative remodeling, but it does not modulate fibrotic remodeling.

LncRNA GAS5 suppresses TGF-ß1-induced transformation of pulmonary pericytes into myofibroblasts by recruiting KDM5B and promoting H3K4me2/3 demethylation of the PDGFRα/ß promoter.

BACKGROUND: Idiopathic pulmonary fibrosis (IPF) is a condition that may cause persistent pulmonary damage. The transformation of pericytes into myofibroblasts has been recognized as a key player during IPF progression. This study aimed to investigate the functions of lncRNA growth arrest-specific transcript 5 (GAS5) in myofibroblast transformation during IPF progression. METHODS: We created a mouse model of pulmonary fibrosis (PF) via intratracheal administration of bleomycin. Pericytes were challenged with exogenous transforming growth factor-ß1 (TGF-ß1). To determine the expression of target molecules, we employed quantitative reverse transcription-polymerase chain reaction, Western blotting, and immunohistochemical and immunofluorescence staining. The pathological changes in the lungs were evaluated via H&E and Masson staining. Furthermore, the subcellular distribution of GAS5 was examined using FISH. Dual-luciferase reporter assay, ChIP, RNA pull-down, and RIP experiments were conducted to determine the molecular interaction. RESULTS: GAS5 expression decreased whereas PDGFRα/ß expression increased in the lungs of IPF patients and mice with bleomycin-induced PF. The in vitro overexpression of GAS5 or silencing of PDGFRα/ß inhibited the TGF-ß1-induced differentiation of pericytes to myofibroblasts, as evidenced by the upregulation of pericyte markers NG2 and desmin as well as downregulation of myofibroblast markers α-SMA and collagen I. Further mechanistic analysis revealed that GAS5 recruited KDM5B to promote H3K4me2/3 demethylation, thereby suppressing PDGFRα/ß expression. In addition, KDM5B overexpression inhibited pericyte-myofibroblast transformation and counteracted the promotional effect of GAS5 knockdown on pericyte-myofibroblast transformation. Lung fibrosis in mice was attenuated by GAS5 overexpression but promoted by GAS5 deficiency. CONCLUSION: GAS5 represses pericyte-myofibroblast transformation by inhibiting PDGFRα/ß expression via KDM5B-mediated H3K4me2/3 demethylation in IPF, identifying GAS5 as an intervention target for IPF.

Detection of FIP1L1-PDGFRA fusion gene-positive cells in the skin lesion of a patient with hypereosinophilic syndrome.

Hypereosinophilic syndrome (HES) is a heterogeneous group of diseases, characterized by persistent hypereosinophilia and end-organ damage. The FIP1L1-PDGFRA (F/P) fusion gene is found in 3-25% of patients with HES and is an oncogenic driver of myeloid neoplasms with clonal eosinophilia. Although cutaneous symptoms are the most common type of symptom in patients who have F/P fusion gene-positive HES (F/P HES), histological reports are limited. We herein present the case of a 78-year-old man with erythematous macules and severe pruritus on his trunk and extremities. Laboratory investigations revealed marked eosinophilia and elevated serum vitamin B12. A histological examination showed massive infiltration of eosinophils and mast cells around the vessels in the upper dermis. Fluorescence in situ hybridization revealed F/P fusion genes in nuclei in the peripheral blood and the skin lesion. The patient was diagnosed with F/P HES, and showed an excellent clinical and haematological response to imatinib.

CT-based assessment of sarcopenia for differentiating wild-type from mutant-type gastrointestinal stromal tumor.

Non-invasive prediction for KIT/PDGFRA status in GIST is a challenging problem. This study aims to evaluate whether CT based sarcopenia could differentiate KIT/PDGFRA wild-type gastrointestinal stromal tumor (wt-GIST) from the mutant-type GIST (mu-GIST), and to evaluate genetic features of GIST. A total of 174 patients with GIST (wt-GIST = 52) were retrospectively identified between January 2011 to October 2019. A sarcopenia nomogram was constructed by multivariate logistic regression. The performance of the nomogram was evaluated by discrimination, calibration curve, and decision curve. Genomic data was obtained from our own specimens and also from the open databases cBioPortal. Data was analyzed by R version 3.6.1 and clusterProfiler ( http://cbioportal.org/msk-impact ). There were significantly higher incidence (75.0% vs. 48.4%) and more severe sarcopenia in patients with wt-GIST than in patients with mu-GIST. Multivariate logistic regression analysis showed that sarcopenia score (fitted based on age, gender and skeletal muscle index), and muscle fat index were independent predictors for higher risk of wt-GIST (P < 0.05 for both the training and validation cohorts). Our sarcopenia nomogram achieved a promising efficiency with an AUC of 0.879 for the training cohort, and 0.9099 for the validation cohort with a satisfying consistency in the calibration curve. Favorable clinical usefulness was observed using decision curve analysis. The additional gene sequencing analysis based on both our data and the external data demonstrated aberrant signal pathways being closely associated with sarcopenia in the wt-GIST. Our study supported the use of CT-based assessment of sarcopenia in differentiating the wt-GIST from the mu-GIST preoperatively.

Comparison of Biomarkers Between Hepatic Tumors in Rat Models and a Dog.

BACKGROUND/AIM: N1S1 rat models are commonly used in human medicine to study hepatocellular carcinoma (HCC). However, their use in veterinary medicine has not been reported. Thus, the aim of this study was to investigate whether the N1S1 rat models could be used to study canine HCC. MATERIALS AND METHODS: The animals were divided into four groups: normal rat, N1S1 rat, normal dog, and HCC dog. Liver tissues of all animals were evaluated for vascular endothelial growth factor (VEGF), epidermal growth factor receptor (EGFR), platelet-derived growth factor receptor (PDGFR)-α, PDGFR-ß, and c-kit by immunohistochemistry. Slides of each factor were scored according to the percentage of stained tumor cells and intensity of the staining. RESULTS: Scores of VEGF and c-kit were high both in the tumor groups (the N1S1 rat and HCC dog groups) and the normal groups of dogs and rats. PDGFR-α was lower in the N1S1 rat group than that in the normal rat group (p=0.0042). It was also lower in the HCC dog group compared to the normal dog group (p=0.0008). PDGFR-ß was higher in the HCC dog group than that in the normal dog group (p=0.0023) but was not detectable in the rat groups. EGFR was not detectable in any group. CONCLUSION: Based on immunochemistry results, PDGFR-α and PDGFR-ß can be used as biomarkers of canine HCC. Because PDGFR-α showed consistency between rats and dogs, it can be used for studying canine HCC.

FIP1L1-PDGFRA fusion gene in T-lymphoblastic lymphoma: A case report.

BACKGROUND: T-lymphoblastic lymphoma (T-LBL) is an aggressive malignancy of T-lymphoid precursors, rarely co-occurring with myeloid/lymphoid neoplasms with eosinophilia (M/LNs-Eo), with consequent rearrangement of tyrosine kinase (TK)-related genes. The FIP1L1-PDGFRA fusion gene is the most frequent molecular abnormality seen in eosinophilia-associated myeloproliferative disorders, but is also present in acute myeloid leukemia (AML), T-lymphoblastic leukemia/lymphoma (TLL), or both simultaneously. T-LBL mainly affects children and young adults, involving lymph node, bone marrow, and thymus. It represents about 85% of all immature lymphoblastic lymphomas, whereas immature B-cell lymphomas comprise approximately 15% of all cases of LBL. CASE: In this case report, we present an example of T cell lymphoblastic lymphoma with coexistent eosinophelia, treated successfully with a tyrosine-kinase inhibitor (TKI). CONCLUSION: FIP1L1-PDGFRA-positive T-LBL and myeloproliferative disorders have excellent response to low-dose treatment with (TKI) imatinib. Most patients achieve rapid and complete hematologic and molecular remission within weeks.

Identification of Homoharringtonine as a potent inhibitor of glioblastoma cell proliferation and migration.

We previously demonstrated that Annexin A2 (ANXA2) is a pivotal mediator of the pro-oncogenic features displayed by glioblastoma (GBM) tumors, the deadliest adult brain malignancies, being involved in cell stemness, proliferation and invasion, thus negatively impacting patient prognosis. Based on these results, we hypothesized that compounds able to revert ANXA2-dependent transcriptional features could be exploited as reliable treatments to inhibit GBM cell aggressiveness by hampering their proliferative and migratory potential. Transcriptional signatures obtained by the modulation of ANXA2 activity/levels were functionally mapped through the QUADrATiC bioinformatic tool for compound identification. Selected compounds were screened by cell proliferation and migration assays in primary GBM cells, and we identified Homoharringtonine (HHT) as a potent inhibitor of GBM cell motility and proliferation, without affecting their viability. A further molecular characterization of the effects displayed by HHT, confirmed its ability to inhibit a transcriptional program involved in cell migration and invasion. Moreover, we demonstrated that the multiple antitumoral effects displayed by HHT are correlated to the inhibition of a platelet derived growth factor receptor α (PDGFRα)-dependent intracellular signaling through the impairment of Signal transducer and activator of transcription 3 (STAT3) and Ras homolog family member A (RhoA) axes. Our results demonstrate that HHT may act as a potent inhibitor of cancer cell proliferation and invasion in GBM, by hampering multiple PDGFRα-dependent oncogenic signals transduced through the STAT3 and RhoA intracellular components, finally suggesting its potential transferability for achieving an effective impairment of peculiar GBM hallmarks.

Development of skeletal muscle atrophy and intermuscular adipose tissue in patients with early breast cancer treated with chemotherapy.

Chemotherapy is a common therapy to treat patients with breast cancer but also leads to skeletal muscle deconditioning. Skeletal muscle deconditioning is multifactorial and intermuscular adipose tissue (IMAT) accumulation is closely linked to muscle dysfunction. To date, there is no clinical study available investigating IMAT development through a longitudinal protocol and the underlying mechanisms remain unknown. Our study was dedicated to investigating IMAT content in patients with early breast cancer who were treated with chemotherapy and exploring the subsequent cellular mechanisms involved in its development. We included 13 women undergoing chemotherapy. Muscle biopsies and ultrasonography assessment were performed before and after chemotherapy completion. Histological and Western blotting analyses were conducted. We found a substantial increase in protein levels of three mature adipocyte markers (perilipin, +901%; adiponectin, +135%; FABP4, +321%; P < 0.05). These results were supported by an increase in oil red O-positive staining (+358%; P < 0.05). A substantial increase in PDGFRα protein levels was observed (+476%; P < 0.05) highlighting an increase in fibro-adipogenic progenitors (FAPs) content. The cross-sectional area of the vastus lateralis muscle fibers substantially decreased (-21%; P < 0.01), and muscle architecture was altered, as shown by a decrease in fascicle length (-15%; P < 0.05) and a decreasing trend in muscle thickness (-8%; P = 0.08). We demonstrated both IMAT development and muscle atrophy in patients with breast cancer who were treated with chemotherapy. FAPs, critical stem cells inducing both IMAT development and skeletal muscle atrophy, also increased, suggesting that FAPs likely play a critical role in the skeletal muscle deconditioning observed in patients with breast cancer who were treated with chemotherapy.