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Purpose: Epithelial–mesenchymal transition (EMT) is a crucial pathological process that contributes to proliferative vitreoretinopathy (PVR), and research indicates that factors present in the vitreous that target cells play pivotal roles in regulating EMT. Experimental studies have confirmed that rabbit vitreous (RV) promotes EMT in human retinal pigment epithelial (RPE) cells. The long noncoding RNA (lncRNA) MALAT1 has been implicated in EMT in various diseases. Thus, this study aimed to investigate the involvement of lncRNA MALAT1 in vitreous-induced EMT in RPE cells. Methods: MALAT1 was knocked down in ARPE-19 cells by short hairpin RNA (shRNA) transfection. Reverse transcription PCR (RT‒PCR) was used to evaluate MALAT1 expression, and Western blotting analysis was used to measure the expression of EMT-related proteins. Wound-healing, Transwell, and cell contraction assays were conducted to assess cell migration, invasion, and contraction, respectively. Additionally, cell proliferation was assessed using the CCK-8 assay, and cytoskeletal changes were examined by immunofluorescence. Results: MALAT1 expression was significantly increased in ARPE-19 cells cultured with RV. Silencing MALAT1 effectively suppressed EMT and downregulated the associated factors snail1 and E-cadherin. Furthermore, silencing MALAT1 inhibited the RV-induced migration, invasion, proliferation, and contraction of ARPE-19 cells. Silencing MALAT1 also decreased RV-induced AKT and P53 phosphorylation. Conclusions: In conclusion, lncRNA MALAT1 participates in regulating vitreous-induced EMT in human RPE cells; these results provide new insight into the pathogenesis of PVR and offer a potential direction for the development of antiproliferative drugs. [ABSTRACT FROM AUTHOR]

The use of tyrosine kinase inhibitors (TKI) has been growing in veterinary oncology and in the past few years several TKI have been tested in dogs. However, different from human medicine, we lack strategies to select patients to be treated with each TKI. Therefore, this study aimed to screen different tumor subtypes regarding TKI target immunoexpression as a predictor strategy to personalize the canine cancer treatment. It included 18 prostatic carcinomas, 36 soft tissue sarcomas, 20 mammary gland tumors, 6 urothelial bladder carcinomas, and 7 tumors from the endocrine system. A total of 87 patients with paraffin blocks were used to perform immunohistochemistry (IHC) of human epidermal growth factor receptor 2 (HER-2), epidermal growth factor receptors 1 (EGFR1), vascular endothelial growth factor receptor 2 (VEGFR-2), platelet derived growth factor receptor beta (PDGFR-β), c-KIT, and extracellular signal-regulated kinase 1/2 (ERK1/ERK2). The immunohistochemical screening revealed a heterogeneous protein expression among histological types with mesenchymal tumors showing the lowest expression level and carcinomas the highest expression. We have demonstrated by IHC screening that HER2, EGFR1, VEGFR-2, PDGFR-β and ERK1/ERK2 are commonly overexpressed in dogs with different carcinomas, and KIT expression is considered relatively low in the analyzed samples. [ABSTRACT FROM AUTHOR]

Aims: The aim of this study was to assess associations between neurological biomarkers and distal sensorimotor polyneuropathy (DSPN). Materials and Methods: Cross‐sectional analyses were based on 1032 participants aged 61–82 years from the population‐based KORA F4 survey, 177 of whom had DSPN at baseline. The prevalence of type 2 diabetes was 20%. Prospective analyses used data from 505 participants without DSPN at baseline, of whom 125 had developed DSPN until the KORA FF4 survey. DSPN was defined based on the examination part of the Michigan Neuropathy Screening Instrument. Serum levels of neurological biomarkers were measured using proximity extension assay technology. Associations between 88 biomarkers and prevalent or incident DSPN were estimated using Poisson regression with robust error variance and are expressed as risk ratios (RR) and 95% CI per 1‐SD increase. Results were adjusted for multiple confounders and multiple testing using the Benjamini–Hochberg procedure. Results: Higher serum levels of CTSC (cathepsin C; RR [95% CI] 1.23 (1.08; 1.39), pB‐H = 0.044) and PDGFRα (platelet‐derived growth factor receptor A; RR [95% CI] 1.21 (1.08; 1.35), pB‐H = 0.044) were associated with prevalent DSPN in the total study sample. CDH3, JAM‐B, LAYN, RGMA and SCARA5 were positively associated with DSPN in the diabetes subgroup, whereas GCP5 was positively associated with DSPN in people without diabetes (all pB‐H for interaction <0.05). None of the biomarkers showed an association with incident DSPN (all pB‐H>0.05). Conclusions: This study identified multiple novel associations between neurological biomarkers and prevalent DSPN, which may be attributable to functions of these proteins in neuroinflammation, neural development and myelination. [ABSTRACT FROM AUTHOR]

Objective To investigate the effect of imatinib on the growth of A549 non-small cell lung cancer transplanted tumors and the expression of PDGFB and PDGFRβ proteins in tumor tissues and stroma in nude mice and to explore the underlying tumor suppression mechanism. Methods A transplantation tumor model of A549 non-small cell lung cancer was established in nude mice. The mice were then randomly divided into four groups: control group (0.9%NaCl), low-dose imatinib group (50 mg/(kg·d)), medium-dose imatinib group (100 mg/(kg·d)), and high-dose imatinib group (200 mg/(kg·d)). The effect of different concentrations of imatinib administered by continuous gavage on tumor growth was observed for 28 days. HE staining was performed to observe the pathological changes of tumor tissues. The expression of PDGF/PDGFR pathway-related proteins and the phosphorylation levels of AKT and ERK1/2 proteins in tumor tissues were detected by Western blot analysis. Double immunofluorescence staining was used to detect the expression of PDGFB and PDGFRβ proteins in the tumor stroma. Results Imatinib inhibited the growth of A549 non-small cell lung cancer cells in nude mice, suppressed the expression of PDGFB in tumor tissues, and decreased the phosphorylation levels of PDGFRβ, AKT, and ERK1/2. The expression of PDGFB and PDGFRβ in tumor stromal fibroblasts of the administered group was significantly lower than that of the control group. Conclusion Imatinib exhibits a pronounced inhibitory effect on A549 xenografts of nude mice with non-small cell lung cancer, and its antitumor mechanism may involve the downregulation of PDGFB and PDGFRβ expression in tumor stromal fibroblasts.

The use of tyrosine kinase inhibitors (TKI) has been growing in veterinary oncology and in the past few years several TKI have been tested in dogs. However, different from human medicine, we lack strategies to select patients to be treated with each TKI. Therefore, this study aimed to screen different tumor subtypes regarding TKI target immunoexpression as a predictor strategy to personalize the canine cancer treatment. It included 18 prostatic carcinomas, 36 soft tissue sarcomas, 20 mammary gland tumors, 6 urothelial bladder carcinomas, and 7 tumors from the endocrine system. A total of 87 patients with paraffin blocks were used to perform immunohistochemistry (IHC) of human epidermal growth factor receptor 2 (HER-2), epidermal growth factor receptors 1 (EGFR1), vascular endothelial growth factor receptor 2 (VEGFR-2), platelet derived growth factor receptor beta (PDGFR-β), c-KIT, and extracellular signal-regulated kinase 1/2 (ERK1/ERK2). The immunohistochemical screening revealed a heterogeneous protein expression among histological types with mesenchymal tumors showing the lowest expression level and carcinomas the highest expression. We have demonstrated by IHC screening that HER2, EGFR1, VEGFR-2, PDGFR-β and ERK1/ERK2 are commonly overexpressed in dogs with different carcinomas, and KIT expression is considered relatively low in the analyzed samples.

Objective To investigate the effect of imatinib on the growth of A549 non-small cell lung cancer transplanted tumors and the expression of PDGFB and PDGFRβ proteins in tumor tissues and stroma in nude mice and to explore the underlying tumor suppression mechanism. Methods A transplantation tumor model of A549 non-small cell lung cancer was established in nude mice. The mice were then randomly divided into four groups: control group (0.9%NaCl), low-dose imatinib group (50 mg/(kg·d)), medium-dose imatinib group (100 mg/(kg·d)), and high-dose imatinib group (200 mg/(kg·d)). The effect of different concentrations of imatinib administered by continuous gavage on tumor growth was observed for 28 days. HE staining was performed to observe the pathological changes of tumor tissues. The expression of PDGF/PDGFR pathway related proteins and the phosphorylation levels of AKT and ERK1/2 proteins in tumor tissues were detected by Western blot analysis. Double immunofluorescence staining was used to detect the expression of PDGFB and PDGFRβ proteins in the tumor stroma. Results Imatinib inhibited the growth of A549 non-small cell lung cancer cells in nude mice, suppressed the expression of PDGFB in tumor tissues, and decreased the phosphorylation levels of PDGFRβ, AKT, and ERK1/2. The expression of PDGFB and PDGFRβ in tumor stromal fibroblasts of the administered group was significantly lower than that of the control group. Conclusion Imatinib exhibits a pronounced inhibitory effect on A549 xenografts of nude mice with non-small cell lung cancer, and its antitumor mechanism may involve the downregulation of PDGFB and PDGFRβ expression in tumor stromal fibroblasts. [ABSTRACT FROM AUTHOR]

Concentric lung vascular wall thickening due to enhanced proliferation of pulmonary arterial smooth muscle cells is an important pathological cause for the elevated pulmonary vascular resistance reported in patients with pulmonary arterial hypertension. We identified a differential role of mammalian target of rapamycin (mTOR) complex 1 and complex 2, two functionally distinct mTOR complexes, in the development of pulmonary hypertension (PH). Inhibition of mTOR complex 1 attenuated the development of PH; however, inhibition of mTOR complex 2 caused spontaneous PH, potentially due to up-regulation of platelet-derived growth factor receptors in pulmonary arterial smooth muscle cells, and compromised the therapeutic effect of the mTOR inhibitors on PH. In addition, we describe a promising therapeutic strategy using combination treatment with the mTOR inhibitors and the platelet-derived growth factor receptor inhibitors on PH and right ventricular hypertrophy. The data from this study provide an important mechanism-based perspective for developing novel therapies for patients with pulmonary arterial hypertension and right heart failure.

Simple Summary: Cancer-associated fibroblasts (CAFs) are abundant in colorectal cancer (CRC) tissues and are essential for tumor growth. Histological analysis of CRC clinical specimens showed that the number of CAFs in liver metastases correlated with the number of CAFs in primary tumors. We hypothesized that the presence of CAFs in metastatic CRC contributes to immune evasion, and thus evaluated the efficacy of dasatinib in targeting CAFs in combination with immunotherapy in a mouse model of liver metastasis. Immunotherapy in combination with dasatinib was shown to reduce stromal components and subsequent immune cell infiltration and promote the activation of tumor immunity and tumor regression in liver metastatic tumors with abundant CAF components. These results suggest that CAFs play an important role in the immune evasion of CRC and that dasatinib is a promising combination agent for increasing immunotherapy sensitivity in metastatic CRC. In this study, we investigated the in vivo metastasis suppression effects of the platelet-derived growth factor receptor inhibitor dasatinib, which targets cancer-associated fibroblasts (CAFs), in combination with an anti-programmed cell death-1 (PD-1) antibody. We classified clinical CRC cases as inflamed, excluded, or desert using immunohistochemical analysis and evaluated the tumor stroma. The excluded type was the most common, and cases with high-volume stroma in the primary lesions also had a high stromal volume in the liver metastatic lesions. Liver-metastasis mouse models with different stromal volumes were established and treatment-induced changes in the tumor immune microenvironment were evaluated. The anti-PD-1 antibody alone exhibited a therapeutic effect for the liver metastases with low stromal volumes but not for the liver metastases with high stromal volumes. In contrast, antitumor effects were observed with anti-PD-1 antibody/dasatinib combination therapy even in the liver metastases with high stromal volumes. Combination therapy reduced the stromal volume, promoted immune cell infiltration, induced antitumor cytotoxic T-cell responses, activated antitumor immunity, and promoted tumor regression. These results suggest that CAFs play an important role in the immune evasion of CRC and that anti-PD-1 antibody/dasatinib combination therapy has potential as a treatment option for patients with metastatic CRC for whom immunotherapy alone is ineffective. [ABSTRACT FROM AUTHOR]

Given the limited treatment options and high mortality rates associated with gastric cancer, there is a need to explore novel therapeutic options. The present study aimed to investigate the efficacy of lenvatinib, a multi-target tyrosine kinase inhibitor, in mitigating the progress of gastric cancer in vitro. Comprehensive analyses were conducted to assess the impact of lenvatinib on gastric cancer cells, focusing on the inhibition of viability, suppression of proliferation, induction of apoptosis and reduction of metastatic potential. The effects of lenvatinib on these activities were determined using 5-ethynyl-2′-deoxyuridine staining, colony formation assay, flow cytometry, western blotting, scratch assay and Transwell assay. In addition, bioinformatics analyses were employed to identify key regulatory targets of lenvatinib, with particular attention given to platelet-derived growth factor receptor β (PDGFRB). In addition, the effects of PDGFRB overexpression on the regulation of lenvatinib were explored. Lenvatinib demonstrated significant inhibitory effects on the viability, proliferation and metastatic capabilities of MKN45 and HGC27 gastric cancer cell lines. Bioinformatics analyses identified PDGFRB as a crucial target of lenvatinib, with its downregulation showing promise in enhancing overall survival rates of patients with gastric cancer. By contrast, PDGFRB overexpression reversed the effects of lenvatinib on cells. The present findings underscore the potential of lenvatinib as a promising therapeutic option in the treatment of gastric cancer. By elucidating its mechanism of action and identifying PDGFRB as a primary target, the present study may aid further clinical advancements. [ABSTRACT FROM AUTHOR]

Persistent truncus arteriosus (PTA) is an uncommon and complex congenital cardiac malformation accounting for about 1.2% of all congenital heart diseases (CHDs), which is caused by a deficiency in the embryonic heart outflow tract's (OFT) septation and remodeling. PDGFRα and PDGFRβ double knockout (DKO) in cardiac neural crest cells (CNCCs) has been reported to cause PTA, but the underlying mechanisms remain unclear. Here, we constructed a PTA mouse model with PDGFRα and PDGFRβ double knockout in Pax3+ CNCCs and described the condensation failure into OFT septum of CNCC-derived cells due to disturbance of cell polarity in the DKO group. In addition, we further explored the mechanism with single-cell RNA sequencing. We found that two main cell differentiation trajectories into vascular smooth muscle cells (VSMCs) from cardiomyocytes (CMs) and mesenchymal cells (MSs), respectively, were interrupted in the DKO group. The process of CM differentiation into VSMC stagnated in a transitional CM I-like state, which contributed to the failure of OFT remodeling and muscular septum formation. On the other hand, a Penk+ transitional MS II cluster closely related to cell condensation into the OFT septum disappeared, which led to the OFT's septation absence directly. In conclusion, the disturbance of CNCC-derived cells caused by PDGFRα and PDGFRβ knockout can lead to the OFT septation disorder and the occurrence of PTA. [ABSTRACT FROM AUTHOR]

Sepsis, defined as life-threatening organ failure caused by a dysregulated host response to severe infection, is a major cause of death among intensive care unit patients. Therapies targeting on immunomodulatory is a new research field in sepsis treatment. B- and T-lymphocyte attenuator (BTLA) is an inhibitory costimulatory factor molecule of B and T lymphocytes. Studies have shown that elevated expression of BTLA in lymphocytes can reduce mortality in sepsis, but its regulatory compounds and the underlying mechanism remains to be elucidated. Here, we show that treatment with CP-673451 significantly decreases mortality of septic mouse. CP-673451 is a PDGFR kinase inhibitor which can promote the expression of BTLA, inhibit the release of chemokines such as CXCL13, and reduce first the chemotaxis of B cells to the peripheral blood and vital organs. CP-673451 also inhibits both the release of cytokines and chemokines such as IL-1β, IL-6, IL-10, TNF-α, CCL1, CCL2 and CCL7 and reduces both the chemotactic ability of T cells. This suggests that CP-673451 may prevent septic death by inhibiting lymphocyte chemotaxis and alleviating "cytokine storm". In conclusion, our study provides a new therapeutic target and an effective compound for sepsis treatment. [ABSTRACT FROM AUTHOR]

Platelet-derived growth factor (PDGF) is one of the most important cytokines associated with pulmonary vascular remodeling in pulmonary arterial hypertension (PAH). PDGF receptor (PDGFR) inhibition exerted therapeutic effects on PAH in clinical trials, but serious side effects warrant the withdrawal of existing drugs. In this study, a novel highly selective PDGFR inhibitor WQ-C-401 was developed, and its effects on PDGFR signaling pathway and pulmonary vascular remodeling in PAH were investigated. Cell proliferation assays and Western blot analysis of PDGFRα/β phosphorylation showed that WQ-C-401 inhibited PDGFR-mediated cell proliferation assay and suppressed PDGFR phosphorylation in a concentration-dependent manner. DiscoverX's KinomeScanTM technology confirmed the good kinome selectivity of WQ-C-401 (S score (1) of PDGFR = (0.01)). In monocrotaline (MCT)-induced PAH rats, intragastric administration of WQ-C-401 (25, 50, 100 mg/kg/d) or imatinib (50 mg/kg/d, positive control) significantly decreased right ventricular systolic pressure (RVSP). Histological analysis demonstrated that WQ-C-401 inhibited pulmonary vascular remodeling by reducing muscularization and fibrosis, as well as alleviated right ventricular hypertrophy in MCT-treated rats. In addition, WQ-C-401 suppressed MCT-induced cell hyperproliferation and CD68+ macrophage infiltration around the pulmonary artery. In vitro , WQ-C-401 inhibited PDGF-BB-induced proliferation and migration of human pulmonary arterial smooth muscle cells (PASMCs). Moreover, Western blot analysis showed that WQ-C-401 concertration-dependently inhibited PDGF-BB-induced phosphorylation of ERK1/2 and PDGFRβ Y751, decreased collagen Ⅰ synthesis and increased alpha smooth muscle actin (α-SMA) expression in PASMCs. Collectively, our results suggest that WQ-C-401 is a selective and potent PDGFR inhibitor which could be a promising drug for the therapeutics of PAH by preventing pulmonary vascular remodeling. [ABSTRACT FROM AUTHOR]

Abstract Olaratumab is a monoclonal antibody that specifically binds to platelet‐derived growth factor receptor alpha (PDGFRα) and blocks receptor activation. We conducted a phase 1 trial to evaluate the safety of olaratumab and determine a recommended dose in combination with three different chemotherapy regimens in children. Patients 25% of patients included neutropenia, anemia, leukopenia, lymphopenia, and thrombocytopenia. Pharmacokinetic profiles of olaratumab with chemotherapy were within the projected range based on adult data. There was one complete response (rhabdomyosarcoma [Part B vincristine/irinotecan arm]) and three partial responses (two rhabdomyosarcoma [Part A doxorubicin arm and Part C doxorubicin arm]; one pineoblastoma [Part B vincristine/irinotecan arm]). Olaratumab was tolerable and safely administered in combination with chemotherapy regimens commonly used in children and adolescents.

Gastrointestinal stromal tumors (GISTs) are rare primary neoplasms of the gastrointestinal tract, mesentery, or omentum. In the past, for patients with resectable tumors, surgery was the only viable treatment option. However, therapy of GISTs has undergone a fundamental change with the advent of receptor tyrosine kinase inhibitors primarily targeting the tyrosine-protein kinase KIT and the platelet-derived growth factor receptor alpha (PDGFRA). Ripretinib is one such novel Type-II tyrosine switch control inhibitor which is used in the treatment of advanced KIT proto-oncogene-driven and PDGFRA-induced tumors, including GISTs. The Food and Drug Administration approved ripretinib on May 15, 2020, for the treatment of adult patients with progressive GISTs who had undergone prior treatment with three or more kinase inhibitors. A comprehensive search in PubMed and other sources were done, using the search terms, “GIST” and ripretinib. On combining all the abstracts and conference proceedings, here we present a comprehensive review on ripretinib's history, pharmacology, and clinical applications.

Platelet-derived growth factor receptor α (PDGFRα) is often considered as a general marker of mesenchymal cells and fibroblasts, but also shows expression in a portion of osteoprogenitor cells. Within the skeleton, Pdgfrα+ mesenchymal cells have been identified in bone marrow and periosteum of long bones, where they play a crucial role in participating in fracture repair. A similar examination of Pdgfrα+ cells in calvarial bone healing has not been examined. Here, we utilize Pdgfrα-CreERTM;mT/mG reporter animals to examine the contribution of Pdgfrα+ mesenchymal cells to calvarial bone repair through histology and single-cell RNA sequencing (scRNA-Seq). Results showed that Pdgfrα+ mesenchymal cells are present in several cell clusters by scRNA-Seq, and by histology a dramatic increase in Pdgfrα+ cells populated the defect site at early timepoints to give rise to healed bone tissue overtime. Notably, diphtheria toxin-mediated ablation of Pdgfrα reporter+ cells resulted in significantly impaired calvarial bone healing. Our findings suggest that Pdgfrα-expressing cells within the calvarial niche play a critical role in the process of calvarial bone repair., (© The Author(s) 2024. Published by Oxford University Press.)

Adult T‐cell leukemia (ATL) is a life‐threatening malignant neoplasm of CD4+ T cells resulted from human T‐cell leukemia virus type I (HTLV‐I). Tax1 protein of HTLV‐I can induce malignant proliferation of T‐cells by modulating the expression of growth factors such as platelet‐derived growth factor (PDGF). Here, we aimed to investigate the proviral load (PVL) of HTLV‐I in ATL and also to evaluate the mRNA expression of B chain of PDGF and PDGF‐β receptors in ATL patients and HTLV‐I‐infected healthy carriers. To this end, peripheral blood mononuclear cells (PBMCs) were isolated by using Ficoll‐Histophaque density centrifugation. The mean of HTLV‐I PVL in ATL patients (42,759 ± 15,737 copies/104 cells [95% CI, 9557‐75962]) was significantly (p =.01) higher than that in healthy carriers (650 ± 107 copies/104 cells [95% CI, 422‐879], respectively. The HTLV‐I PVL in ATL patients exhibited a significant correlation with PBMC count (R =.495, p =.001). The mRNA expression of Tax, B chain of PDGF, and PDGF‐β receptor genes was significantly higher in healthy carriers than in patients with ATL. In conclusion, the expression of the canonical PDGFβ and its receptor, and their correlation with Tax expression cannot be a suitable indicator and/or prognostic factor for progression of ATL in HTLV‐I carriers. [ABSTRACT FROM AUTHOR]

Human adipose-derived stem cells (hASCs) play important roles in regenerative medicine and tissue engineering. However, their clinical applications are limited because of their instability during cell culture. Platelet lysates (PLTs) contain large amounts of growth factors that are useful for manufacturing cellular products. Platelet-derived growth factor (PDGF) is a major growth factor in PLTs and a potent mitogen in hASCs. To optimize growth conditions, the effects of a combination of growth factors on the promotion of hASC proliferation were investigated. Moreover, PDGF-BB combined with vascular endothelial growth factor (VEGF) and hepatocyte growth factor (HGF) markedly enhanced the viability of hASCs compared with the effects of PDGF-BB alone. Neither VEGF nor HGF had any effect alone. All growth factor receptor inhibitors inhibited cell proliferation. Wound healing assays revealed that VEGF and HGF stimulated PDGF-dependent cell migration. The effects of these growth factors on the activation of their cognate receptors and signaling enzymes were assessed using immunoblotting. Phosphorylation of PDGF receptor (PDGFR)β, VEGF receptor (VEGFR)2 and MET proto-oncogene and receptor tyrosine kinase was induced by PDGF-BB treatment, and was further increased by treatment with PDGF-BB/VEGF and PDGF-BB/HGF. The levels of phospho-ERK1/2 and phospho-p38MAPK were increased by these treatments in parallel. Furthermore, the expression levels of SRY-box transcription factor 2 and peroxisome proliferator-activated receptor g were increased in PDGF-BB-treated cells, and PDGF-BB played a dominant role in spheroid formation. The findings of the present study highlighted that PDGF/PDGFR signaling played a predominant role in the proliferation and migration of hASCs, and suggested that PDGF was responsible for the efficacy of other growth factors when hASCs were cultured with PLTs. [ABSTRACT FROM AUTHOR]

As personalized medicine becomes more applicable to oncologic practice, image-guided biopsies will be integral for enabling predictive and pharmacodynamic molecular pathology. Interventional radiology has a key role in defining patient-specific management. Advances in diagnostic techniques, genomics, and proteomics enable a window into subcellular mechanisms driving hyperproliferation, metastatic capabilities, and tumor angiogenesis. A new era of personalized medicine has evolved whereby clinical decisions are adjusted according to a patient's molecular profile. Several mutations and key markers already have been introduced into standard oncologic practice. A broader understanding of personalized oncology will help interventionalists play a greater role in therapy selection and discovery.

Epithelial injury and airway hyperresponsiveness are prominent features of asthma. We have previously demonstrated that laser ablation of single epithelial cells immediately induces global airway constriction through Ca(2+)-dependent smooth muscle shortening. The response is mediated by soluble mediators released from wounded single epithelial cells; however, the soluble mediators and signaling mechanisms have not been identified. In this study, we investigated the nature of the epithelial-derived soluble mediators and the associated signaling pathways that lead to the L-type voltage-dependent Ca(2+) channel (VGCC)-mediated Ca(2+) influx. We found that inhibition of adenosine A1 receptors (or removal of adenosine with adenosine deaminase), cyclooxygenase (COX)-2 or prostaglandin E receptor 3 (EP3) receptors, epidermal growth factor receptor (EGFR), or platelet-derived growth factor receptor (PDGFR) all significantly blocked Ca(2+) oscillations in smooth muscle cells and airway contraction induced by local epithelial injury. Using selective agonists to activate the receptors in the presence and absence of selective receptor antagonists, we found that adenosine activated the signaling pathway A1R→EGFR/PDGFR→COX-2→EP3→VGCCs→calcium-induced calcium release, leading to intracellular Ca(2+) oscillations in airway smooth muscle cells and airway constriction.

Olaratumab is a monoclonal antibody that specifically binds to platelet‐derived growth factor receptor alpha (PDGFRα) and blocks receptor activation. We conducted a phase 1 trial to evaluate the safety of olaratumab and determine a recommended dose in combination with three different chemotherapy regimens in children. Patients <18 years with relapsed/refractory solid or central nervous system tumors were enrolled to two dose levels of olaratumab. Patients received olaratumab monotherapy at 15 mg/kg (Part A) or 20 mg/kg (Part B) on Days 1 and 8 of the first 21‐day cycle, followed by olaratumab combined with standard fixed doses of chemotherapy with doxorubicin, vincristine/irinotecan, or high‐dose ifosfamide by investigator choice for subsequent 21‐day cycles. In Part C, patients received olaratumab 20 mg/kg plus assigned chemotherapy for all cycles. Parts A‐C enrolled 68 patients across three chemotherapy treatment arms; olaratumab in combination with doxorubicin (N = 16), vincristine/irinotecan (N = 26), or ifosfamide (N = 26). Three dose‐limiting toxicities (DLTs) occurred during olaratumab monotherapy (at 15 mg/kg, grade [G] 4 alanine aminotransferase [ALT]; at 20 mg/kg, G3 lung infection and G3 gamma‐glutamyl transferase). One DLT occurred during vincristine/irinotecan with olaratumab 20 mg/kg therapy (G3 ALT). Treatment‐emergent adverse events ≥G3 in >25% of patients included neutropenia, anemia, leukopenia, lymphopenia, and thrombocytopenia. Pharmacokinetic profiles of olaratumab with chemotherapy were within the projected range based on adult data. There was one complete response (rhabdomyosarcoma [Part B vincristine/irinotecan arm]) and three partial responses (two rhabdomyosarcoma [Part A doxorubicin arm and Part C doxorubicin arm]; one pineoblastoma [Part B vincristine/irinotecan arm]). Olaratumab was tolerable and safely administered in combination with chemotherapy regimens commonly used in children and adolescents. [ABSTRACT FROM AUTHOR]

Summary: Background: Olaratumab is a humanized monoclonal antiplatelet-derived growth factor receptor alpha antibody that has been approved in combination with doxorubicin for the treatment of patients with metastatic soft tissue sarcoma (STS). The purpose of this retrospective study was to assess the clinical efficacy in STS patients treated with olaratumab in a real-world setting in Austria. Methods: Retrospectively collected longitudinal data from patients treated between November 2016 and September 2018 at 9 Austrian centers were obtained from the respective medical charts. All patients who received at least one dose of olaratumab were eligible. Parameters of most interest were response rates, progression-free survival (PFS) and overall survival (OS). Results: Altogether 55 patients were included in the analysis. The median age was 58 years. In total, 65.5% (n = 36), 21.8% (n = 12) and 12.7% (n = 7) received olaratumab as first, second or ≥third line treatment, respectively. Olaratumab was administered either in combination with doxorubicin (81.8%, n = 45) or liposomal doxorubicin (16.4%, n = 9); one patient received olaratumab as upfront monotherapy. The median PFS and OS were 2.6 and 11.4 months, respectively. The objective response rate was 11.4% and the disease control rate was 40.9%. Conclusion: In this real-world analysis the outcome was less pronounced compared to the results of both the phase Ib/II approval trial and the confirmatory phase III trial. The latter failed to show an improvement in OS and PFS for the doxorubicin/olaratumab combination. As such, olaratumab should not be used anymore in patients with STS. [ABSTRACT FROM AUTHOR]

White matter (WM) disease is associated with disruption of the gliovascular unit, which involves breach of the blood–brain barrier (BBB). We quantified pericytes as components of the gliovascular unit and assessed their status in vascular and other common dementias. Immunohistochemical and immunofluorescent methods were developed to assess the distribution and quantification of pericytes connected to the frontal lobe WM capillaries. Pericytes with a nucleus were identified by collagen 4 (COL4) and platelet‐derived growth factor receptor‐β (PDGFR‐β) antibodies with further verification using PDGFR‐β‐specific ELISA. We evaluated a total of 124 post‐mortem brains from subjects with post‐stroke dementia (PSD), vascular dementia (VaD), Alzheimer's disease (AD), AD‐VaD (Mixed) and post‐stroke non‐demented (PSND) stroke survivors as well as normal aging controls. COL4 and PDGFR‐β reactive pericytes adopted the characteristic "crescent" or nodule‐like shapes around capillary walls. We estimated densities of pericyte somata to be 225 ±38 and 200 ±13 (SEM) per COL4 mm2 area or 2.0 ± 0.1 and 1.7 ± 0.1 per mm capillary length in young and older aging controls. Remarkably, WM pericytes were reduced by ~35%–45% in the frontal lobe of PSD, VaD, Mixed and AD subjects compared to PSND and controls subjects (P < 0.001). We also found pericyte numbers were correlated with PDGFR‐β reactivity in the WM. Our results first demonstrate a reliable method to quantify COL4‐positive pericytes and then, indicate that deep WM pericytes are decreased across different dementias including PSD, VaD, Mixed and AD. Our findings suggest that downregulation of pericytes is associated with the disruption of the BBB in the deep WM in several aging‐related dementias. [ABSTRACT FROM AUTHOR]

The hepatitis B virus X protein (HBx) has pleiotropic biological effects, which underlies its potential role in cell transformation. However, its involvement in hepatic fibrosis remains unclear. In this study, we wanted to clarify, in vivo , the role of HBx protein in the development of liver fibrosis. Mice transgenic for the full-length HBx (FL-HBx) were used. To create liver fibrosis, FL-HBx transgenic and control mice were chronically exposed to carbon tetrachloride (CCl4). Modulation of the expression of proteins involved in matrix remodeling, hepatic metabolism and epithelial-mesenchymal transition (EMT) were investigated. In transgenic mice, FL-HBx expression potentiates CCl4-induced liver fibrosis with increased expression of proteins involved in matrix remodeling (Collagen1a, α-Sma, PdgfR-β, MMP-13). In FL-HBx transgenic mice, an increase in EMT was observed with a higher transcription of two inflammatory cytokines (TNF-α and TGF-β) and a decrease of glutamine synthetase expression level. This was associated with a sustained cell cycle and hepatocyte polyploidy alteration consistent with p38 and ERK1/2 overactivation, increase of PLK1 transcription, accumulation of SQSTM1/p62 protein and increase expression of Beclin-1. This correlates with a higher expression of tumor progenitor cell markers (AFP, Ly6D and EpCam), indicating a higher risk of progression from fibrosis to hepatocellular carcinoma (HCC) in the presence of FL-HBx protein. In conclusion, our results show that FL-HBx protein enhances the development of liver fibrosis and contributes to the progression of liver disease from chronic hepatitis to HCC. [ABSTRACT FROM AUTHOR]

Endothelial barrier dysfunction is a critical pathophysiological process of sepsis. Impaired endothelial cell migration is one of the main reasons for endothelial dysfunction. Statins may have a protective effect on endothelial barrier function. However, the effect and mechanism of statins on lipopolysaccharide (LPS)‐induced endothelial barrier dysfunction remain unclear. Simvastatin (SV) was loaded in nanostructured lipid carriers to produce SV nanoparticles (SV‐NPs). Normal SV and SV‐NPs were used to treat human umbilical vein vascular endothelial cells (HUVECs) injured by LPS. Barrier function was evaluated by monitoring cell monolayer permeability and transendothelial electrical resistance, and cell migration ability was measured by a wound healing assay. LY294002 and imatinib were used to inhibit the activity of PI3K/Akt and platelet‐derived growth factor receptor (PDGFR) β. IQ‐GTPase‐activating protein 1 (IQGAP1) siRNA was used to knockdown endogenous IQGAP1, which was used to verify the role of the PDGFRβ/PI3K/Akt/IQGAP1 pathway in SV/SV‐NPs‐mediated barrier protection in HUVECs injured by LPS. The results show that SV/SV‐NPs promoted the migration and decreased the permeability of HUVECs treated with LPS, and the efficacy of the SV‐NPs exceeded that of SV significantly. LY294002, imatinib and IQGAP1 siRNA all suppressed the barrier protection of SV/SV‐NPs. SV/SV‐NPs promoted the secretion of platelet‐derived growth factor‐BB (PDGF‐BB) and activated the PDGFRβ/PI3K/Akt/IQGAP1 pathway. SV preparations restored endothelial barrier function by restoring endothelial cell migration, which is involved in the regulation of the PDGFRβ/PI3K/Akt/IQGAP1 pathway and PDGF‐BB secretion. As an appropriate formulation for restoring endothelial dysfunction, SV‐NPs may be more effective than SV. [ABSTRACT FROM AUTHOR]

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Duchenne muscular dystrophy (DMD), caused by the loss of dystrophin, remains incurable. Reduction in muscle regeneration with DMD is associated with the accumulation of fibroadipogenic progenitors (FAPs) differentiating into myofibroblasts and leading to a buildup of the collagenous tissue aggravating DMD pathogenesis. Mesenchymal stromal cells (MSCs) expressing platelet-derived growth factor receptors (PDGFRs) are activated in muscle during DMD progression and give rise to FAPs promoting DMD progression. Here, we hypothesized that muscle dysfunction in DMD could be delayed via genetic or pharmacologic depletion of MSC-derived FAPs. In this paper, we test this hypothesis in dystrophin-deficient mdx mice. To reduce fibro/adipose infiltration and potentiate muscle progenitor cells (MPCs), we used a model for inducible genetic ablation of proliferating MSCs via a suicide transgene, viral thymidine kinase (TK), expressed under the Pdgfrb promoter. We also tested if MSCs from fat tissue, the adipose stromal cells (ASCs), contribute to FAPs and could be targeted in DMD. Pharmacological ablation was performed with a hunter-killer peptide D-CAN targeting ASCs. MSC depletion with these approaches resulted in increased endurance, measured based on treadmill running, as well as grip strength, without significantly affecting fibrosis. Although more research is needed, our results suggest that depletion of pathogenic MSCs mitigates muscle damage and delays the loss of muscle function in mouse models of DMD.

Rheumatoid arthritis (RA) is an autoimmune disease caused by inflammation of the synovium and characterized by chronic polyarthritis that destroys bone and cartilage. Fibroblast-like synoviocytes (FLSs) in the synovium of patients with RA can promote cartilage and bone destruction by producing proteins such as matrix metalloproteinases and receptor activator of NF-κB ligand, thereby representing an important therapeutic target for RA. FLSs have several phenotypes depending on which cell surface proteins and adhesion factors are expressed. Identifying the cellular functions associated with different phenotypes and methods of controlling them are considered essential for developing therapeutic strategies for RA. In this study, synovial tissue was collected from patients with RA and control subjects who required surgery due to ligament injury or fracture. Immunohistological analysis was used to investigate the rates of positivity for phosphorylated platelet-derived growth factor receptor-αβ (pPDGFRαβ) and cadherin-11 (CDH11) expression, and apoptosis-related markers were assessed for each cell phenotype. Next, FLSs were isolated in vitro and stimulated with tumor necrosis factor-α (TNF-α) in addition to a combination of PDGF and transforming growth factor (2GF) to investigate pPDGFRαβ and CDH11 expression and the effects of the inhibition of TNF and cyclin-dependent kinase (CDK) 4/6 on FLSs. Immunohistological analysis showed a large percentage of pPDGFRαβ+CDH11– cells in the sub-lining layer (SL) of patients with RA. These cells exhibited increased B-cell lymphoma-2 expression, reduced TNF receptor-1 expression, resistance to cell death, and abnormal proliferation, suggesting a tendency to accumulate in the synovium. Further, in vitro 2GF stimulation of FLSs lowered, whereas 2GF + TNF stimulation increased the pPDGFRαβ/CDH11 ratio. Hypothesizing that FLSs stimulated with 2GF + TNF would accumulate in vivo in RA, we determined the therapeutic effects of TNF and CDK4/6 inhibitors. The TNF inhibitor lowered the pPDGFRαβ/CDH11 ratio, whereas the CDK4/6 inhibitor suppressed cell proliferation. However, a synergistic effect was not observed by combining both the drugs. We observed an increase in pPDGFRαβ+CDH11– cells in the SL of the RA synovium and accumulation of these cells in the synovium. We found that the TNF inhibitor suppressed FLS activity and the CDK4/6 inhibitor reduced cell proliferation.

Objective: Vasculogenic mimicry (VM) generates an important supplementary form of blood supply in cancer, which many factors regulate. However, the effect of lysyl oxidase (LOX) on VM formation is unclear. In this study, gastric cancer tissues and cells were used to investigate the role of LOX in the formation of VM. Materials and Methods: The samples were collected from 49 patients with a final diagnosis of gastric cancer. According to metastasis (including lymph node metastases and distant metastases), gastric cancer samples were divided into metastasis and non-metastasis groups. Based on the degree of invasion, gastric cancer specimens were divided into T1 + T2 and T3 + T4 groups. The relative expression of LOX was detected using Western blot. The formation of VM was measured by double staining with CD34 and Periodic acid-Schiff (PAS) in gastric cancer tissue slices, and the correlation between LOX and VM was analyzed with Pearson's correlation analysis. Gastric cancer cell line BGC-803 was treated with LOX, β-aminopropionitrile (BAPN, an inhibitor of LOX), and AG1295 or AG1296 (inhibitors of the platelet-derived growth factor receptor). The formation of VM was then measured using PAS staining. The expression of platelet-derived growth factor receptor (PDGFR)α and PDGFRβ in gastric cancer cells was detected by Western blot. Results: In gastric cancer samples, the level of LOX was higher in the metastasis group than in the non-metastasis group ( P < 0.05) and in the T3 + T4 group than in the T1 + T2 group ( P < 0.05). VM formation was greater in the T3+T4 group than in the T1+T2 group ( P < 0.05) and in the metastasis group than in the non-metastasis group ( P < 0.05). The expression level of LOX was positively correlated with VM formation ( P < 0.01). In gastric cancer cells, LOX concentration was positively correlated with the degree of VM, and BAPN concentration was negatively correlated with the degree of VM ( P <0.05). PDGFR levels in the T3+T4 and metastasis groups were relatively higher ( P <0.01) and positively correlated with LOX levels in gastric cancer specimens ( P < 0.01) . The relative expression of PDGFRα and PDGFRβ in gastric cancer cells was up-regulated with increasing LOX and downregulated with increasing BAPN ( P < 0.05). With inhibition of PDGFRα and PDGFRβ using AG1295 or AG1296, VM formation in gastric cancer cells decreased ( P <0.05), but the number of VM structures increased while LOX was added ( P < 0.05). Conclusion: LOX partially promotes the formation of VM in gastric cancer through the PDGF-PDGFR signaling pathway., Competing Interests: Competing Interests: The authors have declared that no competing interest exists., (© The author(s).)

Background: A better definition of biomarkers and biological processes related to local recurrence and disease progression is highly warranted for ductal breast carcinoma in situ (DCIS). Stromal-epithelial interactions are likely of major importance for the biological, clinical, and pathological distinctions between high- and low-risk DCIS cases.Methods: Stromal platelet derived growth factor receptor (PDGFR) was immunohistochemically assessed in two DCIS patient cohorts (n = 458 and n = 80). Cox proportional hazards models were used to calculate the hazard ratios of recurrence. The molecular mechanisms regulating stromal PDGFR expression were investigated in experimental in vitro co-culture systems of DCIS cells and fibroblasts and analyzed using immunoblot and quantitative real-time PCR. Knock-out of JAG1 in DCIS cells and NOTCH2 in fibroblasts was obtained through CRISPR/Cas9. Experimental data were validated by mammary fat pad injection of DCIS and DCIS-JAG1 knock-out cells (10 mice per group). All statistical tests were two-sided.Results: PDGFRα(low)/PDGFRβ(high) fibroblasts were associated with increased risk for recurrence in DCIS (univariate hazard ratio = 1.59, 95% confidence interval [CI] = 1.02 to 2.46; P = .04 Wald test; multivariable hazard ratio = 1.78, 95% CI = 1.07 to 2.97; P = .03). Tissue culture and mouse model studies indicated that this fibroblast phenotype is induced by DCIS cells in a cell contact-dependent manner. Epithelial Jagged1 and fibroblast Notch2 were identified through loss-of-function studies as key juxtacrine signaling components driving the formation of the poor prognosis-associated fibroblast phenotype.Conclusions: A PDGFRα(low)/PDGFRβ(high) fibroblast subset was identified as a marker for high-risk DCIS. The Jagged-1/Notch2/PDGFR stroma-epithelial pathway was described as a novel signaling mechanism regulating this poor prognosis-associated fibroblast subset. In general terms, the study highlights epithelial-stromal crosstalk in DCIS and contributes to ongoing efforts to define clinically relevant fibroblast subsets and their etiology. [ABSTRACT FROM AUTHOR]

Oral squamous cell carcinoma (OSCC) is a cancerous disease with poor prognosis. According to the statistics, the 5-year survival rate has not improved significantly over the past 20 years. The platelet-derived growth factor (PDGF) and its signaling pathway is a key regulator of angiogenesis and tumorigenesis. High level of PDGF and its receptor (PDGFR) have been reported in several types of malignancies. In this study, we investigated the relationship of the molecular expression levels of PDGF and PDGFR with clinicopathological parameters in OSCC. To this end, we measured the mRNA and protein levels of PDGF and PDGFR by real-time quantitative PCR (qRT-PCR), immunohistochemistry, and enzyme-linked immunosorbent assay (ELISA), respectively. We found positive correlations of the mRNA levels of PDGFA, PDGFB, and PDGFRB with lymph node metastasis and poor overall survival (OS). High expression of PDGF, PDGFRA, and PDGFRB were remarkably associated with lymph node metastasis and poor OS, as determined by immunohistochemistry. Preoperative serum levels of PDGF-AA and PDGF-BB had a positive correlation with preoperative platelet count. Elevated serum levels of PDGF-AA. PDGF-BB, and platelet count correlated with lymph node metastasis and an unfavorable outcome. In multivariate Cox regression analysis, PDGFA mRNA, PDGFB mRNA, PDGFRB mRNA, PDGF immunoexpression, PDGFRB immunoexpression, serum PDGF-AA, serum PDGF-BB, and platelet count emerged as significant independent prognostic factors for OS. In vitro, we found that elevated PDGF promotes colony formation, migration, and invasiveness of SAS and OECM-1 cancer cell lines. Our results suggest that the expression level of serum PDGF has the potential to become a useful diagnostic marker for the prognosis of OSCC. In addition, PDGFR should be considered as a potential therapeutic target for OSCC. Furthermore, research should be undertaken to elucidate the role of PDGF and PDGFR regarding the behavior of tumor cells in OSCC.

Chondrosarcoma is a rare malignancy characterized by the production of cartilage matrix, displaying heterogeneous histopathology and clinical behavior. Due to lack of effective treatment for advanced disease, the clinical management of metastatic chondrosarcoma is exceptionally challenging. Chondrosarcomas harbor molecular abnormalities, such as overexpression of platelet-derived growth factor receptor (PDGFR)-alpha and PDGFR-beta, which are required for cancer development, progression, and metastasis. Pazopanib is a potent and selective multitargeted tyrosine kinase inhibitor, which co-inhibits stem cell growth factor receptor (c-KIT), fibroblast growth factor receptor (FGFR), PDGFR, and vascular endothelial growth factor receptor (VEGFR) and has demonstrated clinical activity in patients with advanced previously treated soft tissue sarcoma. Herein, we describe the unique case of a patient with metastatic chondrosarcoma who derived clinical benefit from pazopanib after first-line chemotherapy failure.