New members of the platelet-derived growth factor family of mitogens

Inhibition of myotube formation by platelet-derived growth factor subunit B in QM7 cells

OBJECTIVE

The primary objective of this study was to investigate the role and regulatory mechanisms of platelet-derived growth factor subunit B (PDGFB) in muscle differentiation.

METHODS

In this study, a vector for PDGFB was designed and transfected into quail muscle cells to investigate its role and regulatory mechanism during muscle formation. To investigate the inhibitory mechanisms of PDGFB on myogenic differentiation, the mRNA expression levels of various genes and the phosphorylation of extracellular signal-regulated kinase 1/2 (ERK 1/2), both known to regulate muscle development and differentiation were compared.

RESULTS

PDGFB-overexpressed (OE) cells formed morphologically shorter and thinner myotubes and demonstrated a smaller total myotube area than did the control cells. This result was also confirmed at the molecular level by a reduced amount of myosin heavy chain protein in the PDGFB-OE cells. Therefore, PDGFB inhibits the differentiation of muscle cells. Additionally, the expression of myogenin (MYOG) significantly decreased in the PDGFBOE cells on days 2 and 4 compared with that in the control cells. The phosphorylation of ERK 1/2, an upstream protein that inhibits MYOG expression, increased in the PDGFB-OE cells on day 4 compared with that in the control cells. The decreased expression of MYOG in the PDGFB-OE cells increased by inhibition ERK 1/2 phosphorylation.

CONCLUSION

PDGFB may suppress myogenesis by reducing MYOG expression through ERK 1/2 phosphorylation. These findings can help understand muscle differentiation and potentially improve poultry meat production.

Antifibrotic Drugs against Idiopathic Pulmonary Fibrosis and Pulmonary Fibrosis Induced by COVID-19: Therapeutic Approaches and Potential Diagnostic Biomarkers

The COVID-19 pandemic has had a significant impact on the health and economy of the global population. Even after recovery from the disease, post-COVID-19 symptoms, such as pulmonary fibrosis, continue to be a concern. This narrative review aims to address pulmonary fibrosis (PF) from various perspectives, including the fibrotic mechanisms involved in idiopathic and COVID-19-induced pulmonary fibrosis. On the other hand, we also discuss the current therapeutic drugs in use, as well as those undergoing clinical or preclinical evaluation. Additionally, this article will address various biomarkers with usefulness for PF prediction, diagnosis, treatment, prognosis, and severity assessment in order to provide better treatment strategies for patients with this disease.

G-quadruplexes in cancer-related gene promoters: from identification to therapeutic targeting

INTRODUCTION

Guanine-rich DNA sequences can fold into four-stranded noncanonical secondary structures called G-quadruplexes (G4s) which are widely distributed in functional regions of the human genome, such as telomeres and gene promoter regions. Compelling evidence suggests their involvement in key genome functions such as gene expression and genome stability. Notably, the abundance of G4-forming sequences near transcription start sites suggests their potential involvement in regulating oncogenes.

AREAS COVERED

This review provides an overview of current knowledge on G4s in human oncogene promoters. The most representative G4-binding ligands have also been documented. The objective of this work is to present a comprehensive overview of the most promising targets for the development of novel and highly specific anticancer drugs capable of selectively impacting the expression of individual or a limited number of genes.

EXPERT OPINION

Modulation of G4 formation by specific ligands has been proposed as a powerful new tool to treat cancer through the control of oncogene expression. Actually, most of G4-binding small molecules seem to simultaneously target a range of gene promoter G4s, potentially influencing several critical driver genes in cancer, thus producing significant therapeutic benefits.

Polymeric and Composite Carriers of Protein and Non-Protein Biomolecules for Application in Bone Tissue Engineering

Conventional intake of drugs and active substances is most often based on oral intake of an appropriate dose to achieve the desired effect in the affected area or source of pain. In this case, controlling their distribution in the body is difficult, as the substance also reaches other tissues. This phenomenon results in the occurrence of side effects and the need to increase the concentration of the therapeutic substance to ensure it has the desired effect. The scientific field of tissue engineering proposes a solution to this problem, which creates the possibility of designing intelligent systems for delivering active substances precisely to the site of disease conversion. The following review discusses significant current research strategies as well as examples of polymeric and composite carriers for protein and non-protein biomolecules designed for bone tissue regeneration.

Effect of MNCQQ Cells on Migration of Human Dermal Fibroblast in Diabetic Condition

A major symptom of diabetes mellitus (DM) is unfit hyperglycemia, which leads to impaired wound healing. It has been reported that the migration of fibroblasts can be suppressed under high glucose (HG) conditions. In our previous study, we introduced a serum-free culture method for mononuclear cells (MNCs) called quantity and quality control culture (QQc), which could improve the vasculogenic and tissue regeneration ability of MNCs. In this study, we described a culture model in which we applied a high glucose condition in human dermal fibroblasts to simulate the hyperglycemia condition in diabetic patients. MNC-QQ cells were cocultured with fibroblasts in this model to evaluate its role in improving fibroblasts dysfunction induced by HG and investigate its molecular mechanism. It was proven in this study that the impaired migration of fibroblasts induced by high glucose could be remarkably enhanced by coculture with MNC-QQ cells. PDGF B is known to play important roles in fibroblasts migration. Quantitative PCR revealed that MNC-QQ cells enhanced the gene expressions of PDGF B in fibroblasts under HG. Taken with these results, our data suggested a possibility that MNC-QQ cells accelerate wound healing via improving the fibroblasts migration and promote the gene expressions of PDGF B under diabetic conditions.

Platelet-rich plasma treatment alleviates osteoarthritis-related pain, inflammation, and apoptosis by upregulating the expression levels of microRNA-375 and microRNA-337

OBJECTIVE

The present study was designed to determine the molecular mechanism by which platelet-rich plasma (PRP) acts on Osteoarthritis (OA) -related pain, inflammation, and apoptosis in vivo and in vitro.

MATERIALS AND METHODS

An in vivo OA model was established in rats using anterior cruciate ligament transection, and an in vitro OA model was created by treating chondrocytes with IL-1β. Then, the induced rats and chondrocytes were treated with PRP. Real-time PCR were used to examine the expression of micorRNAs (miRs) and mRNAs of inflammatory cytokines. WB were performed to detect the expression of apoptotic factors and Wnt/β-catenin signals. Structural damage of the cartilage and pain in OA rats were analyzed and represented by Mankin Score, OARSIS score, Tender threshold, and Thermal pain threshold. CCK-8 assay and flow cytometry were used to determine cell viability and apoptosis.

RESULTS

The expression levels of miR-337 and miR-375 were downregulated in the in vivo and vitro OA models; however, PRP treatment elevated their levels. miR-337 and miR-375 inhibition reversed the effects of PRP of reducing tenderness and thermal pain thresholds in OA rats. Moreover, PRP decreased the mRNA expression levels of MMP-13, Bax, and inflammatory factors, such as IL-1β, IL-18, and TNF-α, as well as increased the expression levels of collagen II and antiapoptotic Bcl-2. The decrease in inflammation and apoptosis was reversed by miR-337 and miR-375 inhibition, respectively.

DISCUSSION AND CONCLUSIONS

In conclusion, miR-337 and miR-375 are involved in PRP-delayed OA progression by affecting inflammation and apoptosis.

PDGF-BB induces conversion, proliferation, migration, and collagen synthesis of oral mucosal fibroblasts through PDGFR-β/PI3K/ AKT signaling pathway

OBJECTIVE

To explore the pathogenesis of oral submucosal fibrosis (OSF) by analyzing the impact of Platelet Derived Growth Factor (PDGF)-BB on oral mucosal fibroblasts (FB) and PDGFR-β/Phosphoinositide 3-kinase (PI3K)/serine/threonine protein kinase (AKT) signaling pathway.

METHODS

The isolated and purified oral mucosal fibroblasts were divided into four groups: the control group (CON, 10% FBS DMEM), the PDGF-BB group (40 ng/ml PDGF-BB), the PDGF-BB+IMA group (40 ng/ml PDGF-BB and 60 μmol/L IMA), and the PDGF-BB+LY294002 group (40 ng/ml PDGF-BB and 48 μmol/L LY294002). Primary human FB cells were isolated and cultured for detecting the effects of PDGF-BB on α-smooth muscle actin (α-SMA) by indirect immunofluorescence. 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide, Thiazolyl Blue Tetrazolium Bromide (MTT) method and scratch test were used to detect the proliferation and migration of FB. Western blots were used to detect the synthesis of type I collagen (Col I) and the expression of PDGFR-β/PI3K/AKT signaling pathway-related proteins. The effects of PDGFR-β inhibitor and PI3K inhibitor were observed.

RESULTS

Compared with group CON, group IMA, and group LY294002, α-SMA was upregulated in group PDGF-BB (p< 0.05), with higher OD490 nm value (p< 0.05), narrower average scratch width, and higher relative cell migration rate (p< 0.05). The expression levels of Col I, p-PDGFR-β, p-PI3K, and p-AKT were higher in group PDGF-BB (p< 0.05).

CONCLUSIONS

PDGF-BB induces FB to transform into myofibroblasts (MFB) through the PDGFR-β/PI3K/AKT signaling pathway, and promotes the proliferation, migration, and collagen synthesis.

Understanding angiogenesis and the role of angiogenic growth factors in the vascularisation of engineered tissues

Tissue engineering is a rapidly developing field with many potential clinical applications in tissue and organ regeneration. The development of a mature and stable vasculature within these engineered tissues (ET) remains a significant obstacle. Currently, several growth factors (GFs) have been identified to play key roles within in vivo angiogenesis, including vascular endothelial growth factor (VEGF), platelet derived growth factor (PDGF), FGF and angiopoietins. In this article we attempt to build on in vivo principles to review the single, dual and multiple GF release systems and their effects on promoting angiogenesis. We conclude that multiple GF release systems offer superior results compared to single and dual systems with more stable, mature and larger vessels produced. However, with more complex release systems this raises other problems such as increased cost and significant GF-GF interactions. Upstream regulators and pericyte-coated scaffolds could provide viable alternative to circumnavigate these issues.

Uveal Melanoma Cells Elicit Retinal Pericyte Phenotypical and Biochemical Changes in an in Vitro Model of Coculture

Vascular pericytes are an important cellular component in the tumor microenvironment, however, their role in supporting cancer invasion is poorly understood. We hypothesized that PDGF-BB could be involved in the transition of human retinal pericytes (HRPC) in cancer-activated fibroblasts (CAF), induced by the 92.1 uveal melanoma (UM) cell line. In our model system, HRPC were conditioned by co-culturing with 92.1UM for 6 days (cHRPC), in the presence or absence of imatinib, to block PDGF receptor-β (PDGFRβ). The effects of the treatments were tested by wound healing assay, proliferation assay, RT-PCR, high-content screening, Western blot analysis, and invasion assay. Results showed profound changes in cHRPC shape, with increased proliferation and motility, reduction of NG2 and increase of TGF-β1, α-SMA, vimentin, and FSP-1 protein levels, modulation of PDGF isoform mRNA levels, phospho-PDGFRβ, and PDGFRβ, as well as phospho-STAT3 increases. A reduction of IL-1β and IFNγ and an increase in TNFα, IL10, and TGF-β1, CXCL11, CCL18, and VEGF mRNA in cHRPC were found. Imatinib was effective in preventing all the 92.1UM-induced changes. Moreover, cHRPC elicited a significant increase of 92.1UM cell invasion and active MMP9 protein levels. Our data suggest that retinal microvascular pericytes could promote 92.1UM growth through the acquisition of the CAF phenotype.

Angiogenesis in Hepatocellular Carcinoma; Pathophysiology, Targeted Therapy, and Role of Imaging

Hepatocellular carcinoma (HCC) is one of the most common tumors worldwide, usually occurring on a background of liver cirrhosis. HCC is a highly vascular tumor in which angiogenesis plays a major role in tumor growth and spread. Tumor-induced angiogenesis is usually related to a complex interplay between multiple factors and pathways, with vascular endothelial growth factor being a major player in angiogenesis. In the past decade, understanding of tumor-induced angiogenesis has led to the emergence of novel anti-angiogenic therapies, which act by reducing neo-angiogenesis, and improving patient survival. Currently, Sorafenib and Lenvatinib are being used as the first-line treatment for advanced unresectable HCC. However, a disadvantage of these agents is the presence of numerous side effects. A major challenge in the management of HCC patients being treated with anti-angiogenic therapy is effective monitoring of treatment response, which decides whether to continue treatment or to seek second-line treatment. Several criteria can be used to assess response to treatment, such as quantitative perfusion on cross-sectional imaging and novel/emerging MRI techniques, including a host of known and emerging biomarkers and radiogenomics. This review addresses the pathophysiology of angiogenesis in HCC, accurate imaging assessment of angiogenesis, monitoring effects of anti-angiogenic therapy to guide future treatment and assessing prognosis.

Exosomes derived from platelet-rich plasma present a novel potential in alleviating knee osteoarthritis by promoting proliferation and inhibiting apoptosis of chondrocyte via Wnt/β-catenin signaling pathway

Background

Platelet-rich plasma (PRP) provides a nonsurgical approach for treating osteoarthritis (OA). Exosomes that play vital roles in intercellular communication have been studied extensively. Here, we investigated the therapeutic potential and molecular mechanism of exosomes derived from PRP (PRP-Exos) in alleviating OA.

Methods

Exosomes derived from PRP(PRP-Exos) were isolated and purified using the exoEasy Maxi Kit and then identified and analyzed. Primary rabbit chondrocytes were isolated and treated with interleukin 1 beta (IL-1β) to establish the OA model in vitro. Proliferation, migration, and apoptosis assays were measured and compared between PRP-Exos and activated PRP (PRP-As) to evaluate the therapeutic effects on OA. The mechanism involving the Wnt/β-catenin signaling pathway was investigated by Western blot analysis. In vivo, we established animal knee OA model by surgery to compare the therapeutic effect of PRP-Exos and PRP-As.

Results

We successfully isolated and purified exosomes from PRP using the exoEasy Maxi Kit. We also isolated and identified chondrocytes from the New Zealand white rabbit and established the IL-1β-induced OA model; meanwhile, PRP-Exos and PRP-As both inhibited the release of tumor necrosis factor-α(TNF-α) and there was no statistically significant difference between the two. In proliferation, migration, scratch assay, the promoting effect of PRP-Exos was significantly more better than PRP-As. Furthermore, PRP-Exos could significantly decreased apoptotic rate of OA chondrocyte compared with PRP-As. In Western blot analysis, the expression of β-catenin, and RUNX2, Wnt5a were increased in IL-1β-treated chondrocytes, but PRP-Exos and PRP-As could both reverse these changes, and the reversal effect of the former was better than the latter. In vivo, we found that both PRP-Exos and PRP-As displayed the progression of OA, and the effect of PRP-Exos was obviously better than PRP-As by chondrocyte count and Osteoarthritis Research Society International (OARSI) scoring system.

Conclusion

The therapeutic effects of PRP-Exos on OA were similar or better compared with those of PRP-As in vitro or in vivo. PRP-Exos acting as carriers containing growth factors derived from PRP present a novel therapy for OA by activating the Wnt/β-catenin signaling pathway.

Radiotherapy-induced heart disease: a review of the literature

Radiotherapy as one of the four pillars of cancer therapy plays a critical role in the multimodal treatment of thoracic cancers. Due to significant improvements in overall cancer survival, radiotherapy-induced heart disease (RIHD) has become an increasingly recognized adverse reaction which contributes to major radiation-associated toxicities including non-malignant death. This is especially relevant for patients suffering from diseases with excellent prognosis such as breast cancer or Hodgkin's lymphoma, since RIHD may occur decades after radiotherapy. Preclinical studies have enriched our knowledge of many potential mechanisms by which thoracic radiotherapy induces heart injury. Epidemiological findings in humans reveal that irradiation might increase the risk of cardiac disease at even lower doses than previously assumed. Recent preclinical studies have identified non-invasive methods for evaluation of RIHD. Furthermore, potential options preventing or at least attenuating RIHD have been developed. Ongoing research may enrich our limited knowledge about biological mechanisms of RIHD, identify non-invasive early detection biomarkers and investigate potential treatment options that might attenuate or prevent these unwanted side effects. Here, we present a comprehensive review about the published literature regarding clinical manifestation and pathological alterations in RIHD. Biological mechanisms and treatment options are outlined, and challenges in RIHD treatment are summarized.

Differential prognostic impact of platelet-derived growth factor receptor expression in NSCLC

Preclinical evidence suggests that stromal expression of platelet-derived growth factor receptors (PDGFRs) stimulates tumor development and diminishes intratumoral drug uptake. In non-small cell lung cancer (NSCLC), the clinical relevance of stromal PDGFR expression remains uncertain. Tumor specimens from 553 patients with primary operable stage I-IIIB NSCLC was obtained and tissue micro-arrays (TMA) were constructed (Norwegian cohort). Immunohistochemistry (IHC) was used to evaluate the expression of PDGFRα and -β in stromal cells and to explore their impact on patient survival. Results were validated in a non-related cohort consisting of TMAs of 367 stage I (A and B) NSCLC patients (Swedish cohort). High stromal PDGFRα expression was an independent predictor of increased survival in the overall populations and SCC (squamous cell carcinoma) subgroups of both investigated cohorts. PDGFRβ was an independent predictor of poor survival in the overall Norwegian cohort and an independent predictor of increased survival in the ADC (adenocarcinoma) subgroup of the Swedish cohort. Tumors displaying the combination PDGFRα-low/PDGFRβ-high exhibited inferior survival according to increasing stage in the Norwegian cohort. This study confirms that high stromal expression of PDGFRα is a predictor of increased survival in NSCLC. Further exploration of the prognostic impact of PDGFRβ and the relationship between PDGFRα and -β is warranted.

Complex formation between platelet-derived growth factor receptor β and transforming growth factor β receptor regulates the differentiation of mesenchymal stem cells into cancer-associated fibroblasts

Cancer-associated fibroblasts (CAFs) have recently gained attention as potent targets in cancer therapy because they are a crucial component of the tumor microenvironment and promote the growth and invasion of cancer cells. CAFs differentiate from fibroblasts, mesenchymal stem cells (MSCs), epithelial cells, and other cell types in response to transforming growth factor β (TGFβ) stimulation. The drugs tranilast, imatinib, and pirfenidone reportedly inhibit the differentiation of such cells into CAFs; however, it is unclear how they regulate TGFβ signaling. Here, we differentiated MSCs into CAFs in vitro and investigated which drugs suppressed this differentiation. Based on these results, we focused on platelet-derived growth factor (PDGF) receptor β (PDGFRβ) as a key molecule in the initiation of TGFβ signaling. PDGFRβ transmitted TGFβ signaling in MSCs by forming a complex with TGFβ receptor (TGFβR) independently of stimulation with its well-known ligand PDGF. Inhibitors of the differentiation of MSCs into CAFs attenuated complex formation between PDGFRβ and TGFβR. Moreover, PDGF stimulated PDGFRβ to a lesser extent in CAFs than in MSCs. This study indicates that PDGFRβ and TGFβ-TGFβR signaling cooperatively promote the differentiation of MSCs into CAFs in tumor microenvironments independently of canonical PDGF-PDGFR signaling. We propose that blockade of the interaction between PDGFRβ and TGFβR is a potential strategy to prevent TGFβ-mediated differentiation of MSCs into CAFs.

Endostatin inhibits fibrosis by modulating the PDGFR/ERK signal pathway: an in vitro study

Accumulating evidence indicates that endostatin inhibits fibrosis. However, the mechanism is yet to be clarified. The aim of this study is to evaluate the effect of endostatin on platelet-derived growth factor-BB (PDGF-BB)- or transforming growth factor β1 (TGF-β1)-induced fibrosis in cultured human skin fibroblasts, and to further examine the molecular mechanisms involved. Human dermal fibroblasts were cultured in Dulbecco's modified Eagle's medium (DMEM) and serum-starved for 48 h before treatment. Cells were grouped as follows: "PDGF-BB", "PDGF-BB+ endostatin", "TGF-β1", "TGF-β1+endostatin", "endostatin", and "blank control". The fibroblasts were stimulated with either TGF-β1 or PDGF-BB for 72 h in order to set up the fibrosis model in vitro. The cells were co-cultured with either TGF-β1 or PDGF-BB and endostatin and were used to check the inhibiting effect of endostatin. A blank control group and an endostatin group were used as negative control groups. The biomarkers of fibrosis, including the expression of collagen I, hydroxyproline, and α-smooth muscle actin (α-SMA), were evaluated using an enzyme-linked immunosorbent assay (ELISA) and Western blot. The expression of phosphorylated PDGF receptor β (p-PDGFRβ), PDGFRβ, phosphorylated extracellular signal-regulated kinase (p-ERK), and ERK was detected using Western blot and immunofluorescent staining was used to explore the mechanisms. Both PDGF-BB and TGF-β1 significantly up-regulated the expression of collagen I, hydroxyproline, and α-SMA. Endostatin significantly attenuated both the PDGF-BB- and TGF-β1-induced over-expression of collagen I, hydroxyproline, and α-SMA. PDGF-BB and TGF-β1 both promoted the expression of PDGFR, ERK, and p-ERK. Endostatin inhibited the expression of PDGFR and p-ERK but did not affect the expression of total ERK. Endostatin inhibited hypertrophic scar by modulating the PDGFRβ/ERK pathway. Endostatin could be a promising multi-target drug in future fibrosis therapy.

Developments in the management of advanced soft-tissue sarcoma - olaratumab in context

Lartruvo® (olaratumab) is a fully human immunoglobulin G subclass 1 (IgG1) monoclonal antibody that inhibits platelet-derived growth factor receptor alpha (PDGFRα). The antitumor activity of olaratumab has been tested in vitro and in vivo, and inhibition of tumor growth has been observed in cancer cell lines, including glioblastoma and leiomyosarcoma cells. It represents the first-in-class antibody to be approved by regulatory authorities for the treatment of advanced soft-tissue sarcomas (STSs) in combination with doxorubicin, based on the results of the Phase Ib/II trial by Tap et al. The median progression-free survival (PFS), which was the primary end point of the study, was improved for patients treated with olaratumab plus doxorubicin compared to those treated with doxorubicin monotherapy (6.6 vs 4.1 months, respectively; HR 0.672, 95% CI 0.442-1.021, p=0.0615). Moreover, final analysis of overall survival (OS) showed a median OS of 26.5 months with olaratumab plus doxorubicin vs 14.7 months with doxorubicin, with a gain of 11.8 months (HR 0.46, 95% CI 0.30-0.71, p=0.0003). In October 2016, olaratumab was admitted in the Accelerated Approval Program by the US Food and Drug Administration (FDA) for use in combination with doxorubicin for the treatment of adult patients with STSs. In November 2016, the European Medicines Agency (EMA) granted conditional approval for olaratumab in the same indication under its Accelerated Assessment Program. A double-blind, placebo-controlled, randomized Phase III study (ANNOUNCE trial, NCT02451943) is being performed in order to confirm the survival advantage of olaratumab and to provide definitive drug confirmation by regulators. The study is ongoing, but enrollment is closed. The purpose of this review was to evaluate the rationale of olaratumab in the treatment of advanced STSs and its emerging role in clinical practice.

Improving immunotherapy outcomes with anti-angiogenic treatments and vice versa

Immunotherapies have revolutionized medical oncology following the remarkable and, in some cases, unprecedented outcomes observed in certain groups of patients with cancer. Combination with other therapeutic modalities, including anti-angiogenic agents, is one of the many strategies currently under investigation to improve the response rates and duration of immunotherapies. Such a strategy might seem counterintuitive given that anti-angiogenic agents can increase tumour hypoxia and reduce the number of blood vessels within tumours. Herein, we review the additional effects mediated by drugs targeting VEGF-dependent signalling and other pathways, such as those mediated by angiopoietin 2 or HGF, which might increase the efficacy of immunotherapies. In addition, we discuss the seldom considered possibility that immunotherapies, and immune-checkpoint inhibitors in particular, might increase the efficacy of anti-angiogenic or other types of antivascular therapies and/or promote changes in the tumour vasculature. In short, we propose that interactions between both therapeutic modalities could be considered a 'two-way street'.

Drug targeting to myofibroblasts: Implications for fibrosis and cancer

Myofibroblasts are the key players in extracellular matrix remodeling, a core phenomenon in numerous devastating fibrotic diseases. Not only in organ fibrosis, but also the pivotal role of myofibroblasts in tumor progression, invasion and metastasis has recently been highlighted. Myofibroblast targeting has gained tremendous attention in order to inhibit the progression of incurable fibrotic diseases, or to limit the myofibroblast-induced tumor progression and metastasis. In this review, we outline the origin of myofibroblasts, their general characteristics and functions during fibrosis progression in three major organs: liver, kidneys and lungs as well as in cancer. We will then discuss the state-of-the art drug targeting technologies to myofibroblasts in context of the above-mentioned organs and tumor microenvironment. The overall objective of this review is therefore to advance our understanding in drug targeting to myofibroblasts, and concurrently identify opportunities and challenges for designing new strategies to develop novel diagnostics and therapeutics against fibrosis and cancer.

Olaratumab: A Novel Platelet-Derived Growth Factor Receptor α-Inhibitor for Advanced Soft Tissue Sarcoma

Objective: To review and summarize data on olaratumab, which was approved by the US Food and Drug Administration (FDA) in October 2016, in combination with doxorubicin, for the treatment of advanced soft tissue sarcoma. Data Sources: A literature search using PubMed was conducted using the search terms olaratumab, IMC-3G3, and advanced soft tissue sarcoma from January 2005 to June 2017. Study Selection and Data Extraction: The literature search was confined to human studies published in English. Trials of olaratumab for advanced soft tissue sarcomas were prioritized. Data Synthesis: Olaratumab is a human antiplatelet-derived growth factor receptor α monoclonal antibody. Its accelerated FDA approval was based on a phase II randomized trial of olaratumab plus doxorubicin (n = 66) versus doxorubicin monotherapy (n = 67) in patients with advanced soft tissue sarcoma. Olaratumab 15 mg/kg was administered intravenously (IV) on days 1 and 8 in combination with doxorubicin 75 mg/m2 IV on day 1 every 21 days for a total of 8 cycles compared to doxorubicin 75 mg/m2 IV monotherapy. The response rate was 18.2% with combination therapy versus 11.9% with monotherapy and median progression-free survival of 6.6 and 4.1 months, respectively. Additionally, overall survival was increased by 11.8 months in the olaratumab arm (26.5 months vs 14.7 months). Clinically relevant adverse effects in the olaratumab + doxorubicin arm included neutropenia (58%), mucositis (53%), nausea (73%), vomiting (45%), and diarrhea (34%). Conclusion: Olaratumab, in combination with doxorubicin, represents a novel treatment strategy for advanced soft tissue sarcoma and provides a significant survival advantage for this rare disease state with limited treatment options.

Preparing Platelet-Rich Plasma with Whole Blood Harvested Intraoperatively During Spinal Fusion

BACKGROUND Platelet-rich plasma (PRP) has gained growing popularity in use in spinal fusion procedures in the last decade. Substantial intraoperative blood loss is frequently accompanied with spinal fusion, and it is unknown whether blood harvested intraoperatively qualifies for PRP preparation. MATERIAL AND METHODS Whole blood was harvested intraoperatively and venous blood was collected by venipuncture. Then, we investigated the platelet concentrations in whole blood and PRP, the concentration of growth factors in PRP, and the effects of PRP on the proliferation and viability of human bone marrow-derived mesenchymal stem cells (HBMSCs). RESULTS Our results revealed that intraoperatively harvested whole blood and whole blood collected by venipuncture were similar in platelet concentration. In addition, PRP formulations prepared from both kinds of whole blood were similar in concentration of platelet and growth factors. Additional analysis showed that the similar concentrations of growth factors resulted from the similar platelet concentrations of whole blood and PRP between the two groups. Moreover, these two kinds of PRP formulations had similar effects on promoting cell proliferation and enhancing cell viability. CONCLUSIONS Therefore, intraoperatively harvested whole blood may be a potential option for preparing PRP spinal fusion.

Anti-angiogenic agents for the treatment of solid tumors: Potential pathways, therapy and current strategies - A review

Recent strategies for the treatment of cancer, other than just tumor cell killing have been under intensive development, such as anti-angiogenic therapeutic approach. Angiogenesis inhibition is an important strategy for the treatment of solid tumors, which basically depends on cutting off the blood supply to tumor micro-regions, resulting in pan-hypoxia and pan-necrosis within solid tumor tissues. The differential activation of angiogenesis between normal and tumor tissues makes this process an attractive strategic target for anti-tumor drug discovery. The principles of anti-angiogenic treatment for solid tumors were originally proposed in 1972, and ever since, it has become a putative target for therapies directed against solid tumors. In the early twenty first century, the FDA approved anti-angiogenic drugs, such as bevacizumab and sorafenib for the treatment of several solid tumors. Over the past two decades, researches have continued to improve the performance of anti-angiogenic drugs, describe their drug interaction potential, and uncover possible reasons for potential treatment resistance. Herein, we present an update to the pre-clinical and clinical situations of anti-angiogenic agents and discuss the most recent trends in this field.

Enhancing Vascularization through the Controlled Release of Platelet-Derived Growth Factor-BB

Using delivery systems to control the in vivo release of growth factors (GFs) for tissue engineering applications is extremely desirable as the clinical use of GFs is limited by their fast in vivo turnover. Hence, the development of effective platforms that are able to finely control the release of GFs in vivo remains a challenge. Herein, we investigated the ability of multiscale microspheres, composed by a nanostructured silicon multistage vector (MSV) core and a poly(dl-lactide-co-glycolide) acid (PLGA) forming outer shell (PLGA-MSV), to release functional platelet-derived growth factor-BB (PDGF-BB) to induce in vivo localized neovascularization. The in vitro release of PDGF-BB was assessed by enzyme-linked immunosorbent assay (ELISA) over 2 weeks and showed a sustained, zero-order release kinetics. The ability to promote in vivo localized neovascularization was investigated in a subcutaneous injection model in BALB/c mice and followed by intravital microscopy up to 2 weeks. Fully functional newly formed vessels were found within the area where PLGA-MSVs were localized and covered 3.0 ± 0.9 and 19 ± 5.1% at 7 and 14 days, respectively, showing a 6-fold increase in 1 week. The distribution of CD31⁺ and α-SMA⁺ cells was detected by immunofluorescence on harvested tissues. CD31 was significantly more expressed (4-fold increase) compared to the untreated control. Finally, the level of up-regulation of angiogenesis-associated genes (Vegfa, Vwf, and Col3a1) was assessed by q-PCR, resulting in a significantly higher expression where PLGA-MSVs were localized (Vegfa: 2.32 ± 0.50 at 7 days and 4.37 ± 0.75 at 14 days; Vwf: 4.13 ± 0.82 and 7.74 ± 0.91; Col3a1: 5.43 ± 0.37 and 6.66 ± 0.89). Altogether, our data supported the conclusion that the localized delivery of PDGF-BB from PLGA-MSVs induced the localized de novo formation of fully functional vessels in vivo. With this study, we demonstrated that PLGA-MSV holds promise for accomplishing the controlled localized in vivo release of GFs for the design of innovative tissue engineering strategies.

Comparative evaluation of the effects of platelet‑rich plasma formulations on extracellular matrix formation and the NF‑κB signaling pathway in human articular chondrocytes

Concentrated leukocytes in leukocyte and platelet-rich plasma (L-PRP) may deliver increased levels of pro-inflammatory cytokines to activate the nuclear factor (NF)-κB signaling pathway, to counter or overwhelm the beneficial effects of growth factors on cartilage regeneration. However, to date, no relevant studies have substantiated this. In the present study, L-PRP and pure platelet-rich plasma (P-PRP) were prepared, and leukocytes, platelets, pro-inflammatory cytokines and growth factor concentrations were quantified; they were then used to treat human articular chondrocytes (HACs). Pyrrolidine dithiocarbamate (PDTC; 50 µM) was used to inhibit the activation of NF-κB. The nuclear translocation of NF-κB p65 and the protein expression of cartilaginous markers (collagen II, aggrecan and sex-determining region Y-box 9) were determined using western blot analysis. The mRNA expression of NF-κB-dependent inflammatory mediators, including inducible nitric oxide synthase and cyclooxygenase-2, and cartilaginous markers were determined using reverse transcription-quantitative polymerase chain reaction analysis. The production of prostaglandin E2, nitric oxide and glycosaminoglycan (GAG) were quantified using enzyme-linked immunosorbent assays, the Griess reaction and a 1,9-dimethylmethylene blue assay, respectively. The results demonstrated that L-PRP induced the nuclear translocation of NF-κB p65, upregulated the mRNA expression of NF-κB-dependent inflammatory mediators and upregulated the production of their products, whereas P-PRP, which had similar growth factor concentrations but significantly lower pro-inflammatory cytokine concentrations than L-PRP, did not. P-PRP promoted the mRNA and protein expression levels of cartilaginous markers and the production of GAG more effectively, compared with L-PRP. Furthermore, inhibition of the activation of NF-κB by PDTC enhanced the effects of L-PRP on extracellular matrix formation in the HACs to a level similar to that of P-PRP. These findings suggested that leukocytes in L-PRP activated the NF-κB signaling pathway via the delivery of interleukin-1β and tumor necrosis factor-α to counter the beneficial effects of growth factors on extracellular matrix formation in HACs. Therefore, P-PRP may be more suitable for the treatment of osteoarthritis.

The platelet-derived growth factor receptor/STAT3 signaling pathway regulates the phenotypic transition of corpus cavernosum smooth muscle in rats

Erectile dysfunction (ED) is a common clinical disease that is difficult to treat. We previously found that hypoxia modulates the phenotype of primary corpus cavernosum smooth muscle cells (CCSMCs) in rats, but the underlying molecular mechanism is still unknown. Platelet-derived growth factor receptor (PDGFR)-related signaling pathways are correlated with cell phenotypic transition, but research has been focused more on vascular smooth muscle and tracheal smooth muscle and less on CCSMCs. Here, we investigated the role of PDGFR-related signaling pathways in penile CCSMCs, which were successfully isolated from rats and cultured in vitro. PDGF-BB at 5, 10, or 20 ng/ml altered CCSMC morphology from the original elongated, spindle shape to a broader shape and promoted the synthetic phenotype and expression of the related proteins vimentin and collagen-I, while inhibiting the contractile phenotype and expression of the related proteins smooth muscle (SM) α-actin (α-SMA) and desmin. Inhibition of PDGFR activity via siRNA or the PDGFR inhibitor crenolanib inhibited vimentin and collagen-I expression, increased α-SMA and desmin expression, and considerably inhibited serine-threonine protein kinase (AKT) and signal transducer and activator of transcription 3 (STAT3) phosphorylation. STAT3 knockdown promoted the contractile phenotype, inhibited vimentin and collagen-I expression, and increased α-SMA and desmin expression, whereas AKT knockdown did not affect phenotype-associated proteins. STAT3 overexpression in CCSMC cells weakened the suppressive effect of PDGFR inhibition on the morphology and phenotypic transformation induced by PDGF-BB. Through activation of the PDGFR/STAT3 signaling pathway, PDGF promoted the synthetic phenotype transition; thus, regulation of this pathway might contribute to ED therapy.

Biological characteristics of embryonic epicardial cells in vitro correlate with embryonic day

The epicardial cell (EpiC) culture system plays an important role in investigating the specific mechanisms and signaling molecules that are involved in the development of EpiCs. From this early formation until adulthood, EpiCs undergo dynamic changes in the expression of embryonic genes that correlate with changes in the embryonic EpiC properties. The differences of embryonic EpiC properties may affect the related results of experiments in which EpiC culture system is used; however, these differences have not been explored. Therefore, in this study we examined the differences in the biological characteristics of EpiCs on different embryonic days in vitro EpiCs were isolated from embryonic ventricle explants on embryonic day (E) 11.5, E13.5, and E15.5. The differences in the migration, proliferation and differentiation were studied in EpiCs of different embryonic day by scratch assay, cell cycle analysis and platelet derived growth factor-bb (PDGF-BB) treatment. The results showed that EpiCs were successfully cultured from E11.5, E13.5, and E15.5 embryonic ventricle explants. The time windows of E11.5, E13.5, and E15.5 EpiC isolation out of the explants were different. The migration abilities of E11.5, E13.5, and E15.5 EpiCs decreased during embryonic development. Smooth muscle cell differentiation potential of early stage EpiCs was better than that of the later stage EpiCs. Although the proliferation ability of E11.5 EpiCs was significantly weaker than those of E13.5 and E15.5 EpiCs, the proliferation abilities of E13.5 and E15.5 EpiCs did not differ. These results suggest that the biological characteristics of EpiCs correlate with the timing of embryonic development, and different embryonic stage of ventricle should be properly chosen for culturing EpiCs depending on the purposes of the specific experiments.

Reconstruction of Alar Nasal Cartilage Defects Using a Tissue Engineering Technique Based on a Combined Use of Autologous Chondrocyte Micrografts and Platelet-rich Plasma: Preliminary Clinical and Instrumental Evaluation

BACKGROUND

Developing cartilage constructs with injectability, appropriate matrix composition, and persistent cartilaginous phenotype remains an enduring challenge in cartilage repair. The combined use of autologous chondrocyte micrografts and platelet-rich plasma (PRP) is an alternative that opens a new era in this field.

METHODS

At the Department of Plastic and Reconstructive Surgery, University of Rome Tor Vergata, Italy, 11 patients underwent nasal alar reconstruction with chondrocyte micrografts gently poured onto PRP in solid form. A computed tomographic scan control was performed after 12 months. Pearson's Chi-square test was used to investigate difference in cartilage density between native and newly formed cartilages.

RESULTS

The constructs of chondrocyte micrografts-PRP that were subcutaneously injected resulted in a persistent cartilage tissue with appropriate morphology, adequate central nutritional perfusion without central necrosis or ossification, and further augmented nasal dorsum without obvious contraction and deformation.

CONCLUSION

This report demonstrated that chondrocyte micrografts derived from nasal septum poured onto PRP in solid form are useful for cartilage regeneration in patients with external nasal valve collapse.

Oral Platelet-Derived Growth Factor and Vascular Endothelial Growth Factor Inhibitor Sunitinib Prevents Chronic Allograft Injury in Experimental Kidney Transplantation Model

BACKGROUND

Expression of both platelet-derived growth factor (PDGF) and vascular endothelial growth factor (VEGF) is increased during the development of chronic rejection which remains the major reason for late allograft loss in clinical kidney transplantation. Sunitinib is a tyrosine kinase inhibitor which inhibits both VEGF and PDGF receptors. Here we investigated its effect on the development of chronic rejection.

METHODS

Rat aortic denudation model was used to define sunitinib dose. In vitro studies were done to investigate the effect of sunitinib on smooth muscle cell proliferation and migration. Kidney transplantations were performed from dark agouti rat strain (DA) to Wistar furth rat strain rats and syngenic DA-DA grafts were used as controls. Allografts were immunosuppressed either with cyclosporine or with cyclosporine and sunitinib. Grafts were harvested at 5 and 90 days for histology and immunohistochemistry. Serum creatinine levels were measured weekly to monitor graft function.

RESULTS

Sunitinib decreased neointimal formation and smooth muscle cell proliferation and migration in a dose-dependent manner. Sunitinib was well tolerated and almost completely prevented chronic rejection changes and preserved significantly better renal graft function after transplantation. Sunitinib also inhibited chronic PDGF-A and -B and VEGF-A and -B expressions.

CONCLUSIONS

These results demonstrate that combined inhibition of PGDF and VEGF with sunitinib prevents chronic rejection changes in experimental kidney transplantation which indicates that sunitinib could be a potential intervention also in clinical kidney transplantation.

Advantages of Pure Platelet-Rich Plasma Compared with Leukocyte- and Platelet-Rich Plasma in Treating Rabbit Knee Osteoarthritis

Background

Concentrated leukocytes in leukocyte- and platelet-rich plasma (L-PRP) may deliver increased levels of pro-inflammatory cytokines to activate the NF-κB signaling pathway, to counter the beneficial effects of growth factors on osteoarthritic cartilage. However, to date no relevant studies have substantiated that in vivo.

Material/Methods

Autologous L-PRP and pure platelet-rich plasma (P-PRP) were prepared, measured for componential composition, and injected intra-articularly after 4, 5, and 6 weeks post-anterior cruciate ligament transection. Caffeic acid phenethyl ester (CAPE) was injected intraperitoneally to inhibit NF-κB activation. All rabbits were sacrificed after 8 weeks postoperative. Enzyme-linked immunosorbent assays were performed to determine interleukin 1β (IL-1β) and prostaglandin E2 (PGE2) concentrations in the synovial fluid, Indian ink staining was performed for gross morphological assessment, and hematoxylin and eosin staining and toluidine blue staining were performed for histological assessment.

Results

Compared with L-PRP, P-PRP injections achieved better outcomes regarding the prevention of cartilage destruction, preservation of cartilaginous matrix, and reduction of IL-1β and PGE2 concentrations. CAPE injections reversed the increased IL-1β and PGE2 concentrations in the synovial fluid after L-PRP injections and improved the outcome of L-PRP injections to a level similar to P-PRP injections, while they had no influence on the therapeutic efficacy of P-PRP injections.

Conclusions

Concentrated leukocytes in L-PRP may release increased levels of pro-inflammatory cytokines to activate the NF-κB signaling pathway, to counter the beneficial effects of growth factors on osteoarthritic cartilage, and finally, result in a inferior efficacy of L-PRP to P-PRP for the treatment of osteoarthritis.

Magnobovatol inhibits smooth muscle cell migration by suppressing PDGF-Rβ phosphorylation and inhibiting matrix metalloproteinase-2 expression

The migration of vascular smooth muscle cells (VSMCs) may play a crucial role in the pathogenesis of vascular diseases, such as atherosclerosis and post-angioplasty restenosis. Platelet-derived growth factor (PDGF)-BB is a potent mitogen for VSMCs and plays an important role in the intimal accumulation of VSMCs. Magnobovatol, a new neolignan from the fruits of Magnolia obovata, has been shown to have anticancer properties. However, the effects of magnobovatol on VSMCs are unknown. In the present study, we examined the effects of magnobovatol on the PDGF-BB-induced migration of mouse and human VSMCs, as well as the underlying mechanisms. Magnobovatol significantly inhibited the PDGF-BB-induced migration of mouse and human VSMCs without inducing cell death (as shown by MTT assay and wound healing assay). Additionally, we demonstrated that magnobovatol significantly blocked the PDGF-BB-induced phosphorylation of the PDGF receptor (PDGF-R), Akt and extracellular signal-regulated kinase (ERK)1/2 by inhibiting the activation of the PDGF-BB signaling pathway. Moreover, in both mouse and human VSMCs, magnobovatol inhibited PDGF-induced matrix metalloproteinase (MMP)-2 expression at the mRNA and protein level, as well as the proteolytic activity of MMP-2 (as shown by western blot analysis, RT-PCR, gelatin zymography and ELISA). In addition, the sprout outgrowth formation of aortic rings induced by PDGF-BB was inhibited by magnobovatol (as shown by aortic ring assay). Taken together, our findings indicate that magnobovatol inhibits VSMC migration by decreasing MMP-2 expression through PDGF-R and the ERK1/2 and Akt pathways. Our data may improve the understanding of the anti-atherogenic effects of magnobovatol in VSMCs.

Advantages of pure platelet-rich plasma compared with leukocyte- and platelet-rich plasma in promoting repair of bone defects

Background

High levels of pro-inflammatory cytokines in leukocyte- and platelet-rich plasma (L-PRP) may activate the nuclear factor κB (NF-κB) pathway to counter the beneficial effect of the growth factors on bone regeneration. However, to date, no relevant studies have substantiated this.

Methods

L-PRP and pure platelet-rich plasma (P-PRP) were isolated. The in vitro effects of L-PRP and P-PRP on the proliferation, viability and migration of human bone marrow-derived mesenchymal stem cells (HBMSCs) and EaHy926, tube formation of EaHy926, and osteogenic differentiation of HBMSCs were assessed by cell counting, flow cytometry, scratch assay, tube formation assay, and real-time quantitative polymerase chain reaction (RT-PCR), western blotting and Alizarin red staining, respectively. The in vitro effects of L-PRP and P-PRP on the nuclear translocation of NF-κB p65, mRNA expression of inducible nitric oxide synthase and cyclooxygenase-2, and production of prostaglandin E2 and nitric oxid were assessed by western blotting, RT-PCR, enzyme-linked immunosorbent assay and Griess reaction, respectively. The in vivo effects of L-PRP or P-PRP preprocessed β-tricalcium phosphate (β-TCP) on the calvarial defects in rats were assessed by histological and immunofluorescence examinations.

Results

P-PRP, which had similar platelet and growth factors concentrations but significantly lower concentrations of leukocytes and pro-inflammatory cytokines compared with L-PRP, promoted the proliferation, viability and migration of HBMSCs and EaHy926, tube formation of EaHy926 and osteogenic differentiation of HBMSCs in vitro, compared with L-PRP. The implantation of P-PRP preprocessed β-TCP also yielded better histological results than the implantation of L-PRP preprocessed β-TCP in vivo. Moreover, L-PRP treatment resulted in the activation of the NF-κB pathway in HBMSCs and EaHy926 in vitro while the postoperative delivery of caffeic acid phenethyl ester, an inhibitor of NF-κB activation, enhanced the histological results of the implantation of L-PRP preprocessed β-TCP in vivo.

Conclusions

Leukocytes in L-PRP may activate the NF-κB pathway via the increased pro-inflammatory cytokines to induce the inferior effects on bone regeneration of L-PRP compared with P-PRP. Hence, P-PRP may be more suitable for bone regeneration compared with L-PRP, and the combined use of P-PRP and β-TCP represents a safe, simple, and effective alternative option for autogenous bone graft in the treatment of bone defects.

The molecular basis of hypertrophic scars

Hypertrophic scars (HTS) are caused by dermal injuries such as trauma and burns to the deep dermis, which are red, raised, itchy and painful. They can cause cosmetic disfigurement or contractures if craniofacial areas or mobile region of the skin are affected. Abnormal wound healing with more extracellular matrix deposition than degradation will result in HTS formation. This review will introduce the physiology of wound healing, dermal HTS formation, treatment and difference with keloids in the skin, and it also review the current advance of molecular basis of HTS including the involvement of cytokines, growth factors, and macrophages via chemokine pathway, to bring insights for future prevention and treatment of HTS.

Anti-angiogenic alternatives to VEGF blockade

Angiogenesis is a major requirement for tumour formation and development. Anti-angiogenic treatments aim to starve the tumour of nutrients and oxygen and also guard against metastasis. The main anti-angiogenic agents to date have focused on blocking the pro-angiogenic vascular endothelial growth factors (VEGFs). While this approach has seen some success and has provided a proof of principle that such anti-angiogenic agents can be used as treatment, the overall outcome of VEGF blockade has been somewhat disappointing. There is a current need for new strategies in inhibiting tumour angiogenesis; this article will review current and historical examples in blocking various membrane receptors and components of the extracellular matrix important in angiogenesis. Targeting these newly discovered pro-angiogenic proteins could provide novel strategies for cancer therapy.

Hyaluronan/RHAMM interactions in mesenchymal tumor pathogenesis: role of growth factors

Fibrosarcoma belongs to the sarcoma cancer group, which are spindle cell malignancies of mesenchymal origin, and owe their name to the predominant cell line that is present within the tumor. The extracellular matrix (ECM) is a complicated structure that surrounds and supports cells within tissues. Its main components are proteoglycans, collagens, glycoproteins, hyaluronan (HA), and several matrix-degrading enzymes. During cancer progression, significant changes can be observed in the structural and mechanical properties of ECM components. The ECM provides a physical scaffold to which tumor cells attach and migrate. Thus, it is required for key cellular events such as cell motility, adhesion, proliferation, invasion, and metastasis. Importantly, fibrosarcomas were shown to have a high content and turnover of ECM components including HA, proteoglycans, collagens, fibronectin, and laminin. In this review, we will focus on the HA component of fibrosarcoma ECM and critically discuss its role and involved mechanisms during fibrosarcoma pathogenesis.

Constitutive activation of oncogenic PDGFRα-mutant proteins occurring in GIST patients induces receptor mislocalisation and alters PDGFRα signalling characteristics

Background

Gastrointestinal stromal tumours (GIST) are mainly characterised by the presence of activating mutations in either of the two receptor tyrosine kinases c-KIT or platelet-derived growth factor receptor-α (PDGFRα). Most mechanistic studies dealing with GIST mutations have focused on c-KIT and far less is known about the signalling characteristics of the mutated PDGFRα proteins. Here, we study the signalling capacities and corresponding transcriptional responses of the different PDGFRα proteins under comparable genomic conditions.

Results

We demonstrate that the constitutive signalling via the oncogenic PDGFRα mutants favours a mislocalisation of the receptors and that this modifies the signalling characteristics of the mutated receptors. We show that signalling via the oncogenic PDGFRα mutants is not solely characterised by a constitutive activation of the conventional PDGFRα signalling pathways. In contrast to wild-type PDGFRα signal transduction, the activation of STAT factors (STAT1, STAT3 and STAT5) is an integral part of signalling mediated via mutated PDGF-receptors. Furthermore, this unconventional STAT activation by mutated PDGFRα is already initiated in the endoplasmic reticulum whereas the conventional signalling pathways rather require cell surface expression of the receptor. Finally, we demonstrate that the activation of STAT factors also translates into a biologic response as highlighted by the induction of STAT target genes.

Conclusion

We show that the overall oncogenic response is the result of different signatures emanating from different cellular compartments. Furthermore, STAT mediated responses are an integral part of mutated PDGFRα signalling.

Electronic supplementary material

The online version of this article (doi:10.1186/s12964-015-0096-8) contains supplementary material, which is available to authorized users.

In silico pharmacokinetic and molecular docking studies of small molecules derived from Indigofera aspalathoides Vahl targeting receptor tyrosine kinases

Angiogenesis is the formation of new blood vessels from preexisting vascular network that plays an important role in the tumor growth, invasion and metastasis. Anti-angiogenesis targeting tyrosine kinases such as vascular endothelial growth factor receptor 2 (VEGFR2) and platelet derived growth factor receptor β (PDGFRβ) constitutes a successful target for the treatment of cancer. In this work, molecular docking studies of three bioflavanoid such as indigocarpan, mucronulatol, indigocarpan diacetate and two diterpenes namely erythroxydiol X and Y derived from Indigofera aspalathoides as PDGFRβ and VEGFR2 inhibitors were performed using computational tools. The crystal structures of two target proteins were retrieved from PDB website. Among the five compounds investigated, indigocarpan exhibited potent binding energy ΔG = -7.04 kcal/mol with VEGFR2 and ΔG = -4.82 with PDGFRβ compared to commercially available anti-angiogenic drug sorafenib (positive control). Our results strongly suggested that indigocarpan is a potent angiogenesis inhibitor as ascertained by its potential interaction with VEGFR2 and PDGFRβ. This hypothesis provides a better insight to control metastasis by blocking angiogenesis.

Circadian variation of growth factor levels in platelet-rich plasma

OBJECTIVE

The influence of circadian rhythms has recently been considered in advanced studies of chronopharmacology and chronotherapeutics. Although emerging studies have reported the usefulness of platelet-rich plasma (PRP), no reports have described the diurnal variations in PRP growth factor levels. In the present study, we hypothesized that growth factor levels in PRP show a significant diurnal variation.

DESIGN

Controlled laboratory study.

SETTING

Institutional.

PARTICIPANTS

Ten adult male volunteers (mean age, 30.0 ± 2.6 years; range, 26-34 years).

INTERVENTIONS

Each subject donated a 20-mL sample of fasting blood, 4 times per day (7 AM, 11 AM, 3 PM, and 7 PM).

MAIN OUTCOME MEASURES

Each blood sample was processed to produce PRP. Complete blood counts of peripheral blood (PB) and PRP, as well as quantitative determination of PRP growth factor levels (platelet-derived growth factor and transforming growth factor) were performed. Statistical analyses were conducted using a one-way repeated measures analysis of variance.

RESULTS

No significant differences were observed in platelet, white blood cell, and red blood cell counts in the PB or in the PRP samples throughout the course of the day. In addition, there were no significant differences in PRP growth factor levels at the various time points.

CONCLUSIONS

Significant diurnal variations in platelet counts and growth factor levels were not observed in PRP. Therefore, adjustments for diurnal variation in chronotherapy may not be important when PRP is used in clinical practice.

Overexpression of both platelet-derived growth factor-BB and vascular endothelial growth factor-C and its association with lymphangiogenesis in primary human non-small cell lung cancer

BACKGROUND

Metastatic spread of tumor through lymphatic vasculature is an important adverse prognostic factor in a variety of human cancer and tumor lymphangiogenesis requires the interplay of several growth factors. Platelet-derived growth factor (PDGF)-BB and vascular endothelial growth factor (VEGF)-C are two important molecules involving in tumor metastasis and lymphangiogenesis. Therefore, the aim of this study was to investigate the coexpression of PDGF-BB and VEGF-C in primary human non-small cell lung cancer (NSCLC) and its association with lymphangiogenesis.

METHODS

Using immunohistochemical staining, PDGF-BB and VEGF-C expression were detected in 109 primary NSCLC tissues, while the lymphatic micro-vessel density (LMVD) was counted.

RESULTS

Of 109 cases, PDGF-BB and VEGF-C overexpression was 66.97% (73/109) and 65.14% (71/109), respectively. 52 (47.7%) had overexpression of both PDGF-BB and VEGF-C (P+V+), 21 (19.3%) overexpression of PDGF-BB but low expression of VEGF-C (P+V-), 19(17.4%) overexpression of VEGF-C but low expression of PDGF-BB (P-V+) and 17(15.6%) low expression of both PDGF-BB and VEGF-C (P-V-). PDGF-BB expression was positively related to that of VEGF-C (r=0.451, p=0.034). LMVD in cases with P+V+was much higher than those with P-V- (p=0.004). In addition, the patients with P+V+were younger and also had larger tumor size, more likely lymph node metastasis and worse histological differentiation than those with P-V-. Moreover, the overall survival (OS) of patients with P+V+was shorter than those with P-V- (p=0.015).

CONCLUSION

Coexpression of both PDGF-BB and VEGF-C was associated with lymphangiogenesis and poor prognosis in NSCLC, and might play a critical role in NSCLC progression.

VIRTUAL SLIDES

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/2261801312571320.

Biological pathways and potential targets for prevention and therapy of chronic allograft nephropathy

Renal transplantation (RT) is the best option for patients with end-stage renal disease, but the half-life is limited to a decade due to progressive deterioration of renal function and transplant failure from chronic allograft nephropathy (CAN), which is the leading cause of transplant loss. Extensive research has been done to understand the pathogenesis, the biological pathways of fibrogenesis, and potential therapeutic targets for the prevention and treatment of CAN. Despite the advancements in the immunosuppressive agents and patient care, CAN continues to remain an unresolved problem in renal transplantation. The aim of this paper is to undertake a comprehensive review of the literature on the pathogenesis, biological pathways of RT fibrogenesis, and potential therapeutic targets for the prevention and therapy of CAN.

Antifibrotic and anti-inflammatory activity of the tyrosine kinase inhibitor nintedanib in experimental models of lung fibrosis

The tyrosine kinase inhibitor nintedanib (BIBF 1120) is in clinical development for the treatment of idiopathic pulmonary fibrosis. To explore its mode of action, nintedanib was tested in human lung fibroblasts and mouse models of lung fibrosis. Human lung fibroblasts expressing platelet-derived growth factor (PDGF) receptor-α and -β were stimulated with platelet-derived growth factor BB (homodimer) (PDGF-BB). Receptor activation was assessed by autophosphorylation and cell proliferation by bromodeoxyuridine incorporation. Transforming growth factor β (TGFβ)-induced fibroblast to myofibroblast transformation was determined by α-smooth muscle actin (αSMA) mRNA analysis. Lung fibrosis was induced in mice by intratracheal bleomycin or silica particle administration. Nintedanib was administered every day by gavage at 30, 60, or 100 mg/kg. Preventive nintedanib treatment regimen started on the day that bleomycin was administered. Therapeutic treatment regimen started at various times after the induction of lung fibrosis. Bleomycin caused increased macrophages and lymphocytes in the bronchoalveolar lavage (BAL) and elevated interleukin-1β (IL-1β), tissue inhibitor of metalloproteinase-1 (TIMP-1), and collagen in lung tissue. Histology revealed chronic inflammation and fibrosis. Silica-induced lung pathology additionally showed elevated BAL neutrophils, keratinocyte chemoattractant (KC) levels, and granuloma formation. Nintedanib inhibited PDGF receptor activation, fibroblast proliferation, and fibroblast to myofibroblast transformation. Nintedanib significantly reduced BAL lymphocytes and neutrophils but not macrophages. Furthermore, interleukin-1β, KC, TIMP-1, and lung collagen were significantly reduced. Histologic analysis showed significantly diminished lung inflammation, granuloma formation, and fibrosis. The therapeutic effect was dependent on treatment start and duration. Nintedanib inhibited receptor tyrosine kinase activation and the proliferation and transformation of human lung fibroblasts and showed antifibrotic and anti-inflammatory activity in two animal models of pulmonary fibrosis. These results suggest that nintedanib may impact the progressive course of fibrotic lung diseases such as idiopathic pulmonary fibrosis.

Transcriptome profiling of a multiple recurrent muscle-invasive urothelial carcinoma of the bladder by deep sequencing

Urothelial carcinoma of the bladder (UCB) is one of the commonly diagnosed cancers in the world. The UCB has the highest rate of recurrence of any malignancy. A genome-wide screening of transcriptome dysregulation between cancer and normal tissue would provide insight into the molecular basis of UCB recurrence and is a key step to discovering biomarkers for diagnosis and therapeutic targets. Compared with microarray technology, which is commonly used to identify expression level changes, the recently developed RNA-seq technique has the ability to detect other abnormal regulations in the cancer transcriptome, such as alternative splicing. In this study, we performed high-throughput transcriptome sequencing at ∼50× coverage on a recurrent muscle-invasive cisplatin-resistance UCB tissue and the adjacent non-tumor tissue. The results revealed cancer-specific differentially expressed genes between the tumor and non-tumor tissue enriched in the cell adhesion molecules, focal adhesion and ECM-receptor interaction pathway. Five dysregulated genes, including CDH1, VEGFA, PTPRF, CLDN7, and MMP2 were confirmed by Real time qPCR in the sequencing samples and the additional eleven samples. Our data revealed that more than three hundred genes showed differential splicing patterns between tumor tissue and non-tumor tissue. Among these genes, we filtered 24 cancer-associated alternative splicing genes with differential exon usage. The findings from RNA-Seq were validated by Real time qPCR for CD44, PDGFA, NUMB, and LPHN2. This study provides a comprehensive survey of the UCB transcriptome, which provides better insight into the complexity of regulatory changes during recurrence and metastasis.

Platelet-derived growth factor-BB restores HIV Tat -mediated impairment of neurogenesis: role of GSK-3β/β-catenin

Our previous study demonstrated that platelet-derived growth factor-BB (PDGF-BB) increased the cell proliferation of primary rat neuronal progenitor cells (NPCs). However, whether PDGF-BB regulates neurogenesis in HIV-associated neurological disorder (HAND) remains largely unknown. In this study we demonstrated that pre-treatment of NPCs with PDGF-BB restored Tat-mediated impairment of cell proliferation via activation of p38 and JNK MAPK pathways. Moreover, treatment with PDGF-BB induced inactivation of glycogen synthase kinase-3β (GSK-3β), evidenced by its phosphorylation at Ser9, this effect was significantly inhibited by the p38 and JNK inhibitors. Level of nuclear β-catenin, the primary substrate of GSK-3β, was also concomitantly increased following PDGF-BB treatment, suggesting that PDGF-BB stimulates NPC proliferation via acting on GSK-3β to promote nuclear accumulation of β-catenin. This was further validated by gain and loss of function studies using cells transfected with either the wild type or mutant GSK-3β constructs. Together these data underpin the role of GSK-3β/β-catenin as a novel target that regulates NPC proliferation mediated by PDGF-BB with implications for therapeutic intervention for reversal of impaired neurogenesis inflicted by Tat.

Involvement of miR-9/MCPIP1 axis in PDGF-BB-mediated neurogenesis in neuronal progenitor cells

Highly conserved microRNA-9 (miR-9) has a critical role in various cellular processes including neurogenesis. However, its regulation by neurotropins that are known to mediate neurogenesis remains poorly defined. In this study, we identify platelet-derived growth factor-BB (PDGF-BB)-mediated upregulation of miR-9, which in turn downregulates its target gene monocyte chemotactic protein-induced protein 1 (MCPIP1), as a key player in modulating proliferation, neuronal differentiation as well as migration of neuronal progenitor cells (NPCs). Results indicate that miR-9-mediated NPC proliferation and neuronal differentiation involves signaling via the nuclear factor-kappa B (NF-κB) and cAMP response element-binding protein (CREB) pathways, and that NPC migration involves CREB but not the NF-κB signaling. These findings thus suggest that miR-9-mediated downregulation of MCPIP1 acts as a molecular switch regulation of neurogenesis.

The role of angiogenic factors in fibroid pathogenesis: potential implications for future therapy

BACKGROUND

It is well established that tumors are dependent on angiogenesis for their growth and survival. Although uterine fibroids are known to be benign tumors with reduced vascularization, recent work demonstrates that the vasculature of fibroids is grossly and microscopically abnormal. Accumulating evidence suggests that angiogenic growth factor dysregulation may be implicated in these vascular and other features of fibroid pathophysiology.

METHODS

Literature searches were performed in PubMed and Google Scholar for articles with content related to angiogenic growth factors and myometrium/leiomyoma. The findings are hereby reviewed and discussed.

RESULTS

Multiple growth factors involved in angiogenesis are differentially expressed in leiomyoma compared with myometrium. These include epidermal growth factor (EGF), heparin-binding-EGF, vascular endothelial growth factor, basic fibroblast growth factor, platelet-derived growth factor, transforming growth factor-β and adrenomedullin. An important paradox is that although leiomyoma tissues are hypoxic, leiomyoma feature down-regulation of key molecular regulators of the hypoxia response. Furthermore, the hypoxic milieu of leiomyoma may contribute to fibroid development and growth. Notably, common treatments for fibroids such as GnRH agonists and uterine artery embolization (UAE) are shown to work at least partly via anti-angiogenic mechanisms.

CONCLUSIONS

Angiogenic growth factors play an important role in mechanisms of fibroid pathophysiology, including abnormal vasculature and fibroid growth and survival. Moreover, the fibroid's abnormal vasculature together with its aberrant hypoxic and angiogenic response may make it especially vulnerable to disruption of its vascular supply, a feature which could be exploited for treatment. Further experimental studies are required in order to gain a better understanding of the growth factors that are involved in normal and pathological myometrial angiogenesis, and to assess the potential of anti-angiogenic treatment strategies for uterine fibroids.