Involvement of platelet-derived growth factor ligands and receptors in tumorigenesis

Deubiquitinating enzymes USP4 and USP17 finetune the trafficking of PDGFRβ and affect PDGF-BB-induced STAT3 signalling

Interaction of platelet-derived growth factor (PDGF) isoforms with their receptors results in activation and internalization of receptors, with a concomitant activation of downstream signalling pathways. Ubiquitination of PDGFRs serves as a mark to direct the internalization and sorting of the receptors. By overexpressing a panel of deubiquitinating enzymes (DUBs), we found that USP17 and USP4 efficiently deubiquitinate PDGF receptor β (PDGFRβ) and are able to remove both Lys63 and Lys48-linked polyubiquitin chains from the receptor. Deubiquitination of PDGFRβ did not affect its stability, but regulated the timing of its trafficking, whereby USP17 prolonged the presence of the receptor at the cell surface, while USP4 affected the speed of trafficking towards early endosomes. Induction of each of the DUBs in BJhTERT fibroblasts and U2OS osteosarcoma cells led to prolonged and/or shifted activation of STAT3 in response to PDGF-BB stimulation, which in turn led to increased transcriptional activity of STAT3. Induction of USP17 promoted acute upregulation of the mRNA expression of STAT3-inducible genes STAT3, CSF1, junB and c-myc, while causing long-term changes in the expression of myc and CDKN1A. Deletion of USP17 was lethal to fibroblasts, while deletion of USP4 led to a decreased proliferative response to stimulation by PDGF-BB. Thus, USP17- and USP4-mediated changes in ubiquitination of PDFGRβ lead to dysregulated signalling and transcription downstream of STAT3, resulting in defects in the control of cell proliferation.

Indazole and its Derivatives in Cardiovascular Diseases: Overview, Current Scenario, and Future Perspectives

Indazoles are a class of heterocyclic compounds with a bicyclic ring structure composed of a pyrazole ring and a benzene ring. Indazole-containing compounds with various functional groups have important pharmacological activities and can be used as structural motifs in designing novel drug molecules. Some of the indazole-containing molecules are approved by FDA and are already in the market. However, very few drugs with indazole rings have been developed against cardiovascular diseases. This review aims to summarize the structural and pharmacological functions of indazole derivatives which have shown efficacy against cardiovascular pathologies in experimental settings.

Cumulus Extracellular Matrix Is an Important Part of Oocyte Microenvironment in Ovarian Follicles: Its Remodeling and Proteolytic Degradation

The extracellular matrix (ECM) is an essential structure with biological activities. It has been shown that the ECM influences gene expression via cytoskeletal components and the gene expression is dependent upon cell interactions with molecules and hormones. The development of ovarian follicles is a hormone dependent process. The surge in the luteinizing hormone triggers ovulatory changes in oocyte microenvironment. In this review, we discuss how proteolytic cleavage affects formation of cumulus ECM following hormonal stimulation; in particular, how the specific proteasome inhibitor MG132 affects gonadotropin-induced cytoskeletal structure, the organization of cumulus ECM, steroidogenesis, and nuclear maturation. We found that after the inhibition of proteolytic cleavage, gonadotropin-stimulated oocyte-cumulus complexes (OCCs) were without any signs of cumulus expansion; they remained compact with preserved cytoskeletal F-actin-rich transzonal projections through the oocyte investments. Concomitantly, a significant decrease was detected in progesterone secretion and in the expression of gonadotropin-stimulated cumulus expansion-related transcripts, such as HAS2 and TNFAIP6. In agreement, the covalent binding between hyaluronan and the heavy chains of serum-derived the inter-alpha-trypsin inhibitor, essential for the organization of cumulus ECM, was missing.

Lentiviral-Induced Spinal Cord Gliomas in Rat Model

Intramedullary spinal cord tumors are a rare and understudied cancer with poor treatment options and prognosis. Our prior study used a combination of PDGF-B, HRAS, and p53 knockdown to induce the development of high-grade glioma in the spinal cords of minipigs. In this study, we evaluate the ability of each vector alone and combinations of vectors to produce high-grade spinal cord gliomas. Eight groups of rats (n = 8/group) underwent thoracolumbar laminectomy and injection of lentiviral vector in the lateral white matter of the spinal cord. Each group received a different combination of lentiviral vectors expressing PDGF-B, a constitutively active HRAS mutant, or shRNA targeting p53, or a control vector. All animals were monitored once per week for clinical deficits for 98 days. Tissues were harvested and analyzed using hematoxylin and eosin (H&E) and immunohistochemical (IHC) staining. Rats injected with PDGF-B+HRAS+sh-p53 (triple cocktail) exhibited statistically significant declines in all behavioral measures (Basso Beattie Bresnahan scoring, Tarlov scoring, weight, and survival rate) over time when compared to the control. Histologically, all groups except the control and those injected with sh-p53 displayed the development of tumors at the injection site, although there were differences in the rate of tumor growth and the histopathological features of the lesions between groups. Examination of immunohistochemistry revealed rats receiving triple cocktail displayed the largest and most significant increase in the Ki67 proliferation index and GFAP positivity than any other group. PDGF-B+HRAS also displayed a significant increase in the Ki67 proliferation index. Rats receiving PDGF-B alone and PDGF-B+ sh-p53 displayed more a significant increase in SOX2-positive staining than in any other group. We found that different vector combinations produced differing high-grade glioma models in rodents. The combination of all three vectors produced a model of high-grade glioma more efficiently and aggressively with respect to behavioral, physiological, and histological characteristics than the rest of the vector combinations. Thus, the present rat model of spinal cord glioma may potentially be used to evaluate therapeutic strategies in the future.

Chromosome Imbalances in Neuroblastoma-Recent Molecular Insight into Chromosome 1p-deletion, 2p-gain, and 11q-deletion Identifies New Friends and Foes for the Future

Simple Summary

Neuroblastoma is a pediatric cancer that arises in the sympathetic nervous system. High-risk neuroblastoma is clinically challenging and identification of novel therapies, particularly those that offer a reduction in morbidity for these patients, is a high priority. Combining genetic analyses with investigation of molecular mechanisms, while considering recent advances in our understanding of key developmental events, provides avenues for future treatment. Here we review and highlight several recently published articles that address novel molecular mechanisms arising from chromosome 1p, 2p, and 11q aberrations, which likely contribute to high-risk neuroblastoma, and discusses their potential impact on treatment options.

Abstract

Neuroblastoma is the most common extracranial solid pediatric tumor, with around 15% childhood cancer-related mortality. High-risk neuroblastomas exhibit a range of genetic, morphological, and clinical heterogeneities, which add complexity to diagnosis and treatment with existing modalities. Identification of novel therapies is a high priority in high-risk neuroblastoma, and the combination of genetic analysis with increased mechanistic understanding—including identification of key signaling and developmental events—provides optimism for the future. This focused review highlights several recent findings concerning chromosomes 1p, 2p, and 11q, which link genetic aberrations with aberrant molecular signaling output. These novel molecular insights contribute important knowledge towards more effective treatment strategies for neuroblastoma.

Tyrosine Kinase Inhibitors in Adult Glioblastoma: An (Un)Closed Chapter?

Glioblastoma (GBM) is the most common and lethal form of malignant brain tumor. GBM patients normally undergo surgery plus adjuvant radiotherapy followed by chemotherapy. Numerous studies into the molecular events driving GBM highlight the central role played by the Epidermal Growth Factor Receptor (EGFR), as well as the Platelet-derived Growth Factor Receptors PDGFRA and PDGFRB in tumor initiation and progression. Despite strong preclinical evidence for the therapeutic potential of tyrosine kinase inhibitors (TKIs) that target EGFR, PDGFRs, and other tyrosine kinases, clinical trials performed during the last 20 years have not led to the desired therapeutic breakthrough for GBM patients. While clinical trials are still ongoing, in the medical community there is the perception of TKIs as a lost opportunity in the fight against GBM. In this article, we review the scientific rationale for the use of TKIs targeting glioma drivers. We critically analyze the potential causes for the failure of TKIs in the treatment of GBM, and we propose alternative approaches to the clinical evaluation of TKIs in GBM patients.

Serum Levels of PDGF, EGF, and sFlt-1 in Patients with Polycystic Ovary Syndrome and Their Predictive Effects on Pregnancy Outcomes

Polycystic ovary syndrome (PCOS) is a neuroendocrine disease with complex etiology characterized by infrequent menstruation, follicular developmental disorders, insulin resistance, and hyperandrogenism. PCOS patients often suffer from anovulatory infertility, and even after successful pregnancy promotion, spontaneous abortion is easy to occur. At present, PCOS is mainly diagnosed by auxiliary examinations such as sex hormones and B ultrasonography, and there is a lack of specific serological markers for the diagnosis of diseases. Similarly, there is a lack of effective evaluation methods for the risk of abortion in PCOS patients. Therefore, it is extremely important to explore the factors that affect the occurrence of abortion in PCOS patients and to find specific indicators that can guide the pregnancy outcome of PCOS patients. The purpose of this study was to investigate the serum levels of platelet-derived growth factor (PDGF), epidermal growth factor (EGF), and soluble fms-like tyrosine kinase-1 (sFlt-1) in PCOS patients and analyze their predictive effects on the pregnancy outcomes of PCOS patients. The results showed that serum PDGF, EGF, and sFlt-1 levels were secreted abnormally in PCOS patients with abortion and were closely related to the pregnancy outcome of PCOS patients. The combination of the three levels has the highest value in predicting the pregnancy outcome of PCOS patients, which is worth promoting.

Increased abundance of Cbl E3 ligases alters PDGFR signaling in recessive dystrophic epidermolysis bullosa

In recessive dystrophic epidermolysis bullosa (RDEB), loss of collagen VII, the main component of anchoring fibrils critical for epidermal-dermal cohesion, affects several intracellular signaling pathways and leads to impaired wound healing and fibrosis. In skin fibroblasts, wound healing is also affected by platelet-derived growth factor receptor (PDGFR) signaling. To study a potential effect of loss of collagen VII on PDGFR signaling we performed unbiased disease phosphoproteomics. Whereas RDEB fibroblasts exhibited an overall weaker response to PDGF, Cbl E3 ubiquitin ligases, negative regulators of growth factor signaling, were stronger phosphorylated. This increase in phosphorylation was linked to higher Cbl mRNA and protein levels due to increased TGFβ signaling in RDEB. In turn, increased Cbl levels led to increased PDGFR ubiquitination, internalization, and degradation negatively affecting MAPK and AKT downstream signaling pathways. Thus, our results indicate that elevated TGFβ signaling leads to an attenuated response to growth factors, which contributes to impaired dermal wound healing in RDEB.

Stem cells' centrosomes: How can organelles identified 130 years ago contribute to the future of regenerative medicine?

At the core of regenerative medicine lies the expectation of repair or replacement of damaged tissues or whole organs. Donor scarcity and transplant rejection are major obstacles, and exactly the obstacles that stem cell-based therapy promises to overcome. These therapies demand a comprehensive understanding of the asymmetric division of stem cells, i.e. their ability to produce cells with identical potency or differentiated cells. It is believed that with better understanding, researchers will be able to direct stem cell differentiation. Here, we describe extraordinary advances in manipulating stem cell fate that show that we need to focus on the centrosome and the centrosome-derived primary cilium. This belief comes from the fact that this organelle is the vehicle that coordinates the asymmetric division of stem cells. This is supported by studies that report the significant role of the centrosome/cilium in orchestrating signaling pathways that dictate stem cell fate. We anticipate that there is sufficient evidence to place this organelle at the center of efforts that will shape the future of regenerative medicine.

A SERS-LFA biosensor combined with aptamer recognition for simultaneous detection of thrombin and PDGF-BB in prostate cancer plasma

An innovative surface-enhanced Raman spectroscopy and lateral flow assay (SERS-LFA) biosensor combined with aptamer recognition had been developed for the convenient, rapid, sensitive and accurate detection of thrombin and platelet-derived growth factor-BB (PDGF-BB) associated with prostate cancer simultaneously. During the biosensor operation, thrombin and PDGF-BB in the sample were recognized and combined by thiol-modified aptamers immobilized on Au-Ag hollow nanoparticles (Au-Ag HNPs) surface and biotinylated aptamers immobilized on the test lines of the biosensor. Thus, thrombin and PDGF-BB were simultaneously captured between detection aptamers and capture aptamers in a sandwich structure. Finite difference time domain simulation confirmed that 'hot spots' appeared at the gaps of Au-Ag HNPs dimer in the enhanced electromagnetic field compared to that of a single Au-Ag HNP, indicating that the aggregated Au-Ag HNPs owned a good SERS signal amplification effect. The detection limits of thrombin and PDGF-BB in human plasma were as low as 4.837 pg ml^-1and 3.802 pg ml^-1, respectively. Moreover, the accuracy of the biosensor which was applied to detect thrombin and PDGF-BB in prostate cancer plasma had been verified. This designed biosensor had broad application prospects in the clinical diagnosis of prostate cancer.

Combinatorial immunotherapy of N-803 (IL-15 superagonist) and dinutuximab with ex vivo expanded natural killer cells significantly enhances in vitro cytotoxicity against GD2+ pediatric solid tumors and in vivo survival of xenografted immunodeficient NSG mice

Background

Children with recurrent and/or metastatic osteosarcoma (OS), neuroblastoma (NB) and glioblastoma multiforme (GBM) have a dismal event-free survival (<25%). The majority of these solid tumors highly express GD2. Dinutuximab, an anti-GD2 monoclonal antibody, significantly improved event-free survival in children with GD2⁺ NB post autologous stem cell transplantation and enhanced natural killer (NK) cell-mediated antibody-dependent cell cytotoxicity. Thus, approaches to increase NK cell number and activity, improve persistence and trafficking, and enhance tumor targeting may further improve the clinical benefit of dinutuximab. N-803 is a superagonist of an interleukin-15 (IL-15) variant bound to an IL-15 receptor alpha Su-Fc fusion with enhanced biological activity.

Methods

The anti-tumor combinatorial effects of N-803, dinutuximab and ex vivo expanded peripheral blood NK cells (exPBNK) were performed in vitro using cytoxicity assays against GD2⁺ OS, NB and GBM cells. Perforin and interferon (IFN)-γ levels were measured by ELISA assays. Multiple cytokines/chemokines/growth factors released were measured by multiplex assays. Human OS, GBM or NB xenografted NOD/SCID/IL2rγnull (NSG) mice were used to investigate the anti-tumor combinatorial effects in vivo.

Results

N-803 increased the viability and proliferation of exPBNK. The increased viability and proliferation are associated with increased phosphorylation of Stat3, Stat5, AKT, p38MAPK and the expression of NK activating receptors. The combination of dinutuximab and N-803 significantly enhanced in vitro cytotoxicity of exPBNK with enhanced perforin and IFN-γ release against OS, GBM and NB. The combination of exPBNK+N-803+dinutuximab significantly reduced the secretion of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), platelet-derived growth factor-BB (PDGF-BB), and stem cell growth factor beta (SCGF-β) from OS or GBM tumor cells. Furthermore, OS or GBM significantly inhibited the secretion of regulated on activation, normal T cell expressed and presumably secreted (RANTES) and stromal cell-derived factor-1 alpha (SDF-1α) from exPBNK cells (p<0.001) but significantly enhanced monokine induced by gamma interferon (MIG) secretion from exPBNK cells (p<0.001). N-803 combined with dinutuximab and exPBNK cells significantly extended the survival of OS, GBM or NB xenografted NSG mice.

Conclusions

Our results provide the rationale for the development of a clinical trial of N-803 in combination with dinutuximab and ex vivo exPBNK cells in patients with recurrent or metastatic GD2⁺ solid tumors.

PDGF-BB regulates the transformation of fibroblasts into cancer-associated fibroblasts via the lncRNA LURAP1L-AS1/LURAP1L/IKK/IκB/NF-κB signaling pathway

The most abundant cells in the tumor microenvironment are cancer-associated fibroblasts (CAFs). They play an important role in oral squamous cell carcinoma (OSCC) angiogenesis, invasion and metastasis. Platelet-derived growth factor (PDGF)-BB has an obvious regulating effect on the formation of CAFs through binding to PDGF receptor (PDGFR)-β, but the role of long non-coding (lnc)RNA in PDGF-BB-induced transformation of fibroblasts into CAFs remains poorly understood. Using an lncRNA ChIP, 370 lncRNA transcripts were identified to be significantly and differentially expressed between fibroblasts and PDGF-BB-induced fibroblasts, including 240 upregulated lncRNAs and 130 downregulated lncRNAs, indicating that lncRNAs are involved in the regulation of the transformation of CAFs. Previous studies have shown that the nuclear factor (NF)-κB signaling pathway plays an important role in the activation of CAFs. Dual-luciferase reporter assay and co-immunoprecipitation were conducted to confirm that the leucine-rich adaptor protein 1-like (LURAP1L), which is the target of lncRNA LURAP1L antisense RNA 1 (LURAP1L-AS1) had a positive regulatory effect on I-κB kinase (IKK)/NF-κB signaling. Therefore, LURAP1L-AS1 was selected and PDGF-BB was demonstrated to upregulate the expression of LURAP1L-AS1 and LURAP1L, which was reversed by a PDGFR-β inhibitor. Subsequently, knocking down LURAP1L-AS1 suppressed the expression of PDGF-BB-induced fibroblast activation marker protein α-smooth muscle actin, fibroblast activation protein-α, PDGFR-β and phosphorylated (p)-PDGFR-β. IKKα, p-IĸB and p-NF-κB were downregulated by the knockdown of LURAP1L-AS1 and upregulated by overexpression of LURAP1L-AS1. The present study indicates that LURAP1L-AS1/LURAP1L/IKK/IĸB/NF-κB plays an important regulatory role in PDGF-BB-induced fibroblast activation and may become a potential target for the treatment of OSCC.

Future Perspectives of Therapeutic, Diagnostic and Prognostic Aptamers in Eye Pathological Angiogenesis

Aptamers are single-stranded DNA or RNA oligonucleotides that are currently used in clinical trials due to their selectivity and specificity to bind small molecules such as proteins, peptides, viral particles, vitamins, metal ions and even whole cells. Aptamers are highly specific to their targets, they are smaller than antibodies and fragment antibodies, they can be easily conjugated to multiple surfaces and ions and controllable post-production modifications can be performed. Aptamers have been therapeutically used for age-related macular degeneration, cancer, thrombosis and inflammatory diseases. The aim of this review is to highlight the therapeutic, diagnostic and prognostic possibilities associated with aptamers, focusing on eye pathological angiogenesis.

An antibody-like peptidic network for anti-angiogenesis

Different from chemical (small molecular inhibitor) and biological (monoclonal antibody) drugs, herein, based on angiogenesis-related neuropilin-1 (NRP-1), we develop a biomimetic superstructure drug, i.e. an antibody-like peptidic network (ALPN) to achieve the high-efficient treatment of choroidal neovascularization (CNV). The ALPN in nanoparticulated formulation (ALPN-NP_S) can bind NRP-1 through targeting unit and form fibrous peptidic networks trapping NRP-1 on the surface of endothelial cells (ECs), leading to anti-angiogenesis. The ALPN shows high-efficacy against angiogenesis in CNV rat model ascribed to the superstructure-enhanced binding and blockage of NRP-1. The very low dose of ALPN (0.263 μg/Kg) exhibits similar anti-angiogenesis effect comparing with monoclonal antibody bevacizumab (23.5 μg/Kg), which shows potential advantages over traditional monoclonal antibodies.

Gene expression profile of epithelial-mesenchymal transition mediators in papillary thyroid cancer

PURPOSE

Platelet derived growth receptor alpha (PDGFRA) promotes the epithelial-mesenchymal transition (EMT) in thyroid follicular cells and is linked to lymphatic metastases in papillary thyroid cancer (PTC). We probed the regulatory network of genes linked to PDGFRA and EMT, comparing matched patient primary tumor and metastatic specimens, as well as engineered cell lines and ex vivo primary cultures with and without PDGFRA.

METHODS

Freshly isolated thyroid tumors with or without metastases, with matching neighboring benign or normal tissue, was isolated for comparative transcriptional analysis using a TaqMan Low Density array (TLDA) assay with genes representing important markers of EMT, cellular adhesion, apoptosis, differentiation, senescence, and signal transduction pathways in thyroid cancer. Transfected primary cultures and immortalized cell lines were also analyzed with respect to PDGFRA expression and cell phenotype.

RESULTS

We reveal the consistent upregulation of serine protease DPP4 and structural protein SPP1 with the progression of PTC to metastatic disease, as well as with PDGFRA expression. Conversely, epithelial integrity gene TFF3 and transcription factor SOX10 were strongly down-regulated. This gene network also includes important mediators of EMT including DSG1, MMP3, MMP9, and BECN. We observed similar genomic changes in ex vivo normal thyroid cells transfected with PDGFRA that also exhibited a partially dedifferentiated phenotype. In particular, we observed lamellopodia with induction of PDGFRA and illustrate that DPP4 and SPP1 were upregulated in this process, with decreased TFF3 and SOX10 as seen in tissue specimens. PDGFRA did decrease nuclear protein levels of differentiation factor TTF1, but not the transcription of TTF1 and PAX8.

CONCLUSIONS

We demonstrate that PDGFRA activates EMT pathways and decreases expression of genes favoring epithelial integrity, pushing follicular cells toward a dedifferentiated phenotype. SPP1 and DPP4, previously linked with adverse outcomes in thyroid cancer, appear to be regulated by PDGFRA. PDGFRA expression promotes metastatic disease through multiple EMT levers that favor formation of an invasive phenotype and increased metalloproteinase expression.

Neuropilin-2 and Its Transcript Variants Correlate with Clinical Outcome in Bladder Cancer

Urothelial bladder cancer ranks among the 10 most frequently diagnosed cancers worldwide. In our previous study, the transmembrane protein neuropilin-2 (NRP2) emerged as a predictive marker in patients with bladder cancer. NRP2 consists of several splice variants; the most abundant of these, NRP2a and NRP2b, are reported to have different biological functions in lung cancer progression. For other cancer types, there are no published data on the role of these transcript variants in cancer progression and the clinical outcome. Here, we correlate NRP2 and its two most abundant transcript variants, NRP2A and NRP2B, with the clinical outcome using available genomic data with subsequent validation in our own cohort of patients with muscle-invasive bladder cancer. In addition to NRP2, NRP1 and the NRP ligands PDGFC and PDGFD were studied. Only NRP2A emerged as an independent prognostic marker for shorter cancer-specific survival in muscle-invasive bladder cancer in our cohort of 102 patients who underwent radical cystectomy between 2008 and 2014 with a median follow-up time of 82 months. Additionally, we demonstrate that high messenger expression of NRP2, NRP1, PDGFC and PDGFD associates with a more aggressive disease (i.e., a high T stage, positive lymph node status and reduced survival).

TMEM119 facilitates ovarian cancer cell proliferation, invasion, and migration via the PDGFRB/PI3K/AKT signaling pathway

Background

Ovarian cancer (OV) is the deadliest gynecological cancer. Transmembrane protein 119 (TMEM119) has been reported as oncogene in several human cancers. However, the function of TMEM119 in OV is still poorly known.

Methods

Western blot and qRT-PCR were used to analyze TMEM119 levels. Transwell assays, wound healing assays, CCK-8 assays and EdU cell proliferation assays were designed to explore the function and potential mechanism of TMEM119 in malignant biological behaviors in OV.

Results

TMEM119 was observed to be overexpressed in OV tissues and associated with poor survival in OV patients. Knockdown and overexpression experiments demonstrated that TMEM119 promoted proliferation, invasion, and migration in OV cells in vitro. TMEM119 mRNA expression was related to the pathways of focal adhesion according to Gene Set Enrichment Analyses and was correlated with the mRNA expression level of platelet-derived growth factor receptor beta (PDGFRB). TMEM119 exerted oncogenic effects partially by regulating the expression of PDGFRB and by activating the PI3K/AKT signaling pathway.

Conclusions

Collectively, our findings highlight the potential role of TMEM119 in the malignant biological behavior of OV, which may serve as a potential biomarker and a therapeutic candidate for OV.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-021-02781-x.

Platelet-derived growth factor beta is a potent inflammatory driver in paediatric high-grade glioma

Paediatric high-grade gliomas (HGGs) account for the most brain tumour-related deaths in children and have a median survival of 12-15 months. One promising avenue of research is the development of novel therapies targeting the properties of non-neoplastic cell-types within the tumour such as tumour associated macrophages (TAMs). TAMs are immunosuppressive and promote tumour malignancy in adult HGG; however, in paediatric medulloblastoma, TAMs exhibit anti-tumour properties. Much is known about TAMs in adult HGG, yet little is known about them in the paediatric setting. This raises the question of whether paediatric HGGs possess a distinct constituency of TAMs because of their unique genetic landscapes. Using human paediatric HGG tissue samples and murine models of paediatric HGG, we demonstrate diffuse midline gliomas possess a greater inflammatory gene expression profile compared to hemispheric paediatric HGGs. We also show despite possessing sparse T-cell infiltration, human paediatric HGGs possess high infiltration of IBA1+ TAMs. CD31, PDGFRβ, and PDGFB all strongly correlate with IBA1+ TAM infiltration. To investigate the TAM population, we used the RCAS/tv-a system to recapitulate paediatric HGG in newborn immunocompetent mice. Tumours are induced in Nestin-positive brain cells by PDGFA or PDGFB overexpression with Cdkn2a or Tp53 co-mutations. Tumours driven by PDGFB have a significantly lower median survival compared to PDGFA-driven tumours and have increased TAM infiltration. NanoString and quantitative PCR analysis indicates PDGFB-driven tumours have a highly inflammatory microenvironment characterized by high chemokine expression. In vitro bone marrow-derived monocyte and microglial cultures demonstrate bone marrow-derived monocytes are most responsible for the production of inflammatory signals in the tumour microenvironment in response to PDGFB stimulation. Lastly, using knockout mice deficient for individual chemokines, we demonstrate the feasibility of reducing TAM infiltration and prolonging survival in both PDGFA and PDGFB-driven tumours. We identify CCL3 as a potential key chemokine in these processes in both humans and mice. Together, these studies provide evidence for the potent inflammatory effects PDGFB has in paediatric HGGs.

Mechanisms Underlying Hepatocellular Carcinoma Progression in Patients with Type 2 Diabetes

Hepatocellular carcinoma (HCC) ranks third in cancer-related deaths from solid tumors worldwide. The incidence of type 2 diabetes mellitus (T2DM) has increased worldwide in conjunction with the expansion of the Western lifestyle. Furthermore, patients with T2DM have been documented to have an increased risk of HCC, as well as bile tract cancer. Growing evidence shows that T2DM is a strong additive metabolic risk factor for HCC, but how diabetes affects the incidence of HCC requires additional investigation. In this review, we discuss the underlying mechanisms of HCC in patients with T2DM. Topics covered include abnormal glucose and lipid metabolism, hyperinsulinemia, and insulin resistance; the effect of activated platelets; hub gene expression associated with HCC; inflammation and signaling pathways; miRNAs; altered gut microbiota and immunomodulation. The evidence suggests that reducing obesity, diabetes, and nonalcoholic fatty liver disease/nonalcoholic steatohepatitis through efficient measures of prevention may lead to decreased rates of T2DM-related HCC.

ALK ligand ALKAL2 potentiates MYCN-driven neuroblastoma in the absence of ALK mutation

High-risk neuroblastoma (NB) is responsible for a disproportionate number of childhood deaths due to cancer. One indicator of high-risk NB is amplification of the neural MYC (MYCN) oncogene, which is currently therapeutically intractable. Identification of anaplastic lymphoma kinase (ALK) as an NB oncogene raised the possibility of using ALK tyrosine kinase inhibitors (TKIs) in treatment of patients with activating ALK mutations. 8-10% of primary NB patients are ALK-positive, a figure that increases in the relapsed population. ALK is activated by the ALKAL2 ligand located on chromosome 2p, along with ALK and MYCN, in the "2p-gain" region associated with NB. Dysregulation of ALK ligand in NB has not been addressed, although one of the first oncogenes described was v-sis that shares > 90% homology with PDGF. Therefore, we tested whether ALKAL2 ligand could potentiate NB progression in the absence of ALK mutation. We show that ALKAL2 overexpression in mice drives ALK TKI-sensitive NB in the absence of ALK mutation, suggesting that additional NB patients, such as those exhibiting 2p-gain, may benefit from ALK TKI-based therapeutic intervention.

Induction of muscle-regenerative multipotent stem cells from human adipocytes by PDGF-AB and 5-azacytidine

Terminally differentiated murine osteocytes and adipocytes can be reprogrammed using platelet-derived growth factor-AB and 5-azacytidine into multipotent stem cells with stromal cell characteristics. We have now optimized culture conditions to reprogram human adipocytes into induced multipotent stem (iMS) cells and characterized their molecular and functional properties. Although the basal transcriptomes of adipocyte-derived iMS cells and adipose tissue-derived mesenchymal stem cells were similar, there were changes in histone modifications and CpG methylation at cis-regulatory regions consistent with an epigenetic landscape that was primed for tissue development and differentiation. In a non-specific tissue injury xenograft model, iMS cells contributed directly to muscle, bone, cartilage, and blood vessels, with no evidence of teratogenic potential. In a cardiotoxin muscle injury model, iMS cells contributed specifically to satellite cells and myofibers without ectopic tissue formation. Together, human adipocyte-derived iMS cells regenerate tissues in a context-dependent manner without ectopic or neoplastic growth.

SRC Signaling in Cancer and Tumor Microenvironment

Pioneering experiments performed by Harold Varmus and Mike Bishop in 1976 led to one of the most influential discoveries in cancer research and identified the first cancer-causing oncogene called Src. Later experimental and clinical evidence suggested that Src kinase plays a significant role in promoting tumor growth and progression and its activity is associated with poor patient survival. Thus, several Src inhibitors were developed and approved by FDA for treatment of cancer patients. Tumor microenvironment (TME) is a highly complex and dynamic milieu where significant cross-talk occurs between cancer cells and TME components, which consist of tumor-associated macrophages, fibroblasts, and other immune and vascular cells. Growth factors and chemokines activate multiple signaling cascades in TME and induce multiple kinases and pathways, including Src, leading to tumor growth, invasion/metastasis, angiogenesis, drug resistance, and progression. Here, we will systemically evaluate recent findings regarding regulation of Src and significance of targeting Src in cancer therapy.

Development of a Peptide Derived from Platelet-Derived Growth Factor (PDGF-BB) into a Potential Drug Candidate for the Treatment of Wounds

Objective: This study evaluated the use of novel peptides derived from platelet-derived growth factor (PDGF-BB) as potential wound healing stimulants. One of the compounds (named PDGF2) was subjected for further research after cytotoxicity and proliferation assays on human skin cells. Further investigation included evaluation of: migration and chemotaxis of skin cells, immunological and allergic safety, the transcriptional analyses of adipose-derived stem cells (ASCs) and dermal fibroblasts stimulated with PDGF2, and the use of dorsal skin wound injury model to evaluate the effect of wound healing in mice. Approach: Colorimetric lactate dehydrogenase and tetrazolium assays were used to evaluate the cytotoxicity and the effect on proliferation. PDGF2 effect on migration and chemotaxis was also checked. Immunological safety and allergic potential were evaluated with a lymphocyte activation and basophil activation test. Transcriptional profiles of ASCs and primary fibroblasts were assessed after stimulation with PDGF2. Eight-week-old BALB/c female mice were used for dorsal skin wound injury model. Results: PDGF2 showed low cytotoxicity, pro-proliferative effects on human skin cells, high immunological safety, and accelerated wound healing in mouse model. Furthermore, transcriptomic analysis of ASCs and fibroblasts revealed the activation of processes involved in wound healing and indicated its safety. Innovation: A novel peptide derived from PDGF-BB was proved to be safe drug candidate in wound healing. We also present a multifaceted in vitro model for the initial screening of new compounds that may be potentially useful in wound healing stimulation. Conclusion: The results show that peptide derived from PDGF-BB is a promising drug candidate for wound treatment.

Total Flavonoids of Rhizoma Drynariae Enhances Angiogenic-Osteogenic Coupling During Distraction Osteogenesis by Promoting Type H Vessel Formation Through PDGF-BB/PDGFR-β Instead of HIF-1α/ VEGF Axis

Background: Total flavonoids of Rhizoma Drynariae (TFRD), extracted from the kidney-tonifying traditional Chinese medicine Rhizoma Rrynariae, has been proved to be effective in treating osteoporosis, bone fractures and defects. However, pharmacological effects of TFRD on type H vessels, angiogenic-osteogenic coupling in distraction osteogenesis (DO) and the mechanism remain unclear. This study aims at investigating whether type H vessels exist in the DO model, effects of TFRD on angiogenic-osteogenic coupling and further elucidating the underlying mechanism.

Methods: Rats models of DO and bone fracture (FR) were established, and then were separately divided into TFRD and control subgroups. Imageological and histological analyses were performed to assess bone and vessel formation. Immunofluorescent staining of CD31 and endomucin (Emcn) was conducted to determine type H vessel formation. Matrigel tube formation, ALP and Alizarin Red S staining assays were performed to test the effects of TFRD on angiogenesis or osteogenesis of endothelial precursor cells (EPCs) or bone marrow-derived mesenchymal stem cells (BMSCs). Additionally, expression levels of HIF-1α, VEGF, PDGF-BB, RUNX2 and OSX were determined by ELISA, qPCR or western blot, respectively.

Results: The in vivo results indicated more formed type H vessels in DO groups than in FR groups and TFRD obviously increased the abundance of type H vessels. Moreover, groups with higher abundance of type H vessels showed better angiogenesis and osteogenesis outcomes. Further in vitro experiments showed that TFRD significantly promoted while blocking PDGF-BB remarkably suppressed the angiogenic activity of EPCs under stress conditions. The levels of p-AKT and p-ERK1/2, downstream mediators of the PDGF-BB pathway, were up-regulated by TFRD but blocked by function blocking anti-PDGF-BB antibody. In contrast, the activated AKT and ERK1/2 and corresponding tube formation were not affected by the HIF-1α inhibitor. Besides, blocking PDGF-BB inhibited the osteogenic differentiation of the stretched BMSCs, but TFRD enhanced the osteogenic activity of BMSCs and ameliorated the inhibition, with more calcium nodes, higher ALP activity and mRNA and protein levels of RUNX2 and OSX.

Conclusion: Type H vessels exist in the DO model and TFRD enhances angiogenic-osteogenic coupling during DO by promoting type H vessel formation via PDGF-BB/PDGFR-β instead of HIF-1α/VEGF axis.

Dysregulated PDGFR alpha expression and novel somatic mutations in colorectal cancer: association to RAS wild type status and tumor size

Background

Platelet derived growth factor receptor alpha (PDGFRα) has been considered as a relevant factor in tumor proliferation, angiogenesis and metastatic dissemination. It was a target of tyrosine kinase (TK) inhibitors emerged in the therapy of diverse cancers. In colorectal cancer, the commonly used therapy is anti-epithelial growth factor receptor (EGFR). However, both RAS mutated and a subgroup of RAS wild type patients resist to such therapy. The aim of this study is to investigate PDGFRα protein expression and mutational status in colorectal adenocarcinoma and their association with clinicopathological features and molecular RAS status to provide useful information for the identification of an effective biomarker that might be implicated in prognosis and treatment prediction.

Methods

Our study enrolled 103 formalin fixed paraffin-embedded (FFPE) colorectal adenocarcinoma. PDGFRα expression was investigated by immunohistochemistry (IHC). Hotspot exon 18 of PDGFRA was studied by PCR followed by Sanger sequencing and RAS status was determined by real time quantitative PCR. Thirteen normal colon tissues were used as negative controls.

Results

PDGFRα staining was detected in the cytoplasm of all tissues. Low expression was observed in all normal colon mucosa. In adenocarcinoma, 45% (45/100) of cases showed PDGFRα overexpression. This overexpression was significantly associated with mutations in exon 18 (P = 0.024), RAS wild type status (P < 10^–3), tumor diameter (P = 0.048), whereas there was no association with tumor side (P = 0.13) and other clinicopathological features.

Conclusion

Overexpression of PDGFRα in adenocarcinoma suggests its potential role in tumor cells growth and invasion. The association between PDGFRα overexpression in both tumor and stromal adenocarcinoma cells with RAS wild type status suggests its potential role in anti-EGFR therapy resistance and the relevance of using it as specific or adjuvant therapeutic target.

Correlation between the Serum Platelet-Derived Growth Factor, Angiopoietin-1, and Severity of Coronary Heart Disease

Background

The expression of the platelet-derived growth factor (PDGF), angiopoietin-1 (Ang-1) in patients with coronary artery disease of different studies was inconsistent. This study was to investigate the expression of the PDGF and Ang-1 in peripheral blood and coronary artery in patients with acute coronary syndrome (ACS) and the relationship between the expression of the PDGF and Ang-1 and the severity of coronary artery disease.

Methods

A total of 81 patients with acute coronary syndrome undergoing coronary angiography were enrolled from September 2012 to December 2013. Patients with ACS included 61 patients with acute myocardial infarction (AMI group) and 20 patients with unstable angina pectoris (UAP group). The 29 patients who were hospitalized for chest pain undergoing coronary angiography without stenosis and with TIMI level 3 blood flow were selected as the control group. During coronary arteriography (CAG) or percutaneous coronary intervention (PCI), blood in the peripheral artery and in the local coronary artery was collected from all the patients. Serum PDGF and Ang-1 levels were measured by ELISA. We calculated the Gensini score of each patient with CHD according to the result of CAG. Patients with ACS were followed up, and the major adverse cardiovascular and cerebrovascular adverse events were recorded.

Results

In peripheral blood, the concentration of the PDGF was significantly elevated in the ACS group than that of the control group. The level of the PDGF in the AMI group was significantly higher than that in the UAP group. In coronary artery blood, the level of the PDGF in the ACS group was significantly higher than that of the UAP group. There was no significant difference in the concentration of Ang-1 in peripheral blood between patients with coronary heart disease and the control group. The concentration of Ang-1 in the coronary artery was significantly lower than that in peripheral blood. The coronary Ang-1 concentrations in the ACS group were significantly higher than those in the UAP group. The concentrations of the PDGF and Ang-1 in peripheral and coronary artery blood were positively correlated with the severity of coronary lesions. Patients with MACCE had higher PDGF and Ang-1 levels in the coronary sinus.

Conclusion

The serum PDGF concentration in patients with acute coronary syndrome was significantly increased, especially in the local coronary artery. The serum Ang-1 in the coronary artery was significantly increased in patients with acute myocardial infarction and was related to the degree of coronary artery stenosis. Coronary sinus PDGF and Ang-1 levels can reflect the severity of lesions in patients with acute coronary syndrome.

The hallmarks of cancer are also the hallmarks of wound healing

The Hanahan and Weinberg "hallmarks of cancer" papers provide a useful structure for considering the various mechanisms driving cancer progression, and the same might be useful for wound healing. In this Review, we highlight how tissue repair and cancer share cellular and molecular processes that are regulated in a wound but misregulated in cancer. From sustained proliferative signaling and the activation of invasion and angiogenesis to the promoting role of inflammation, there are many obvious parallels through which one process can inform the other. For some hallmarks, the parallels are more obscure. We propose some new prospective hallmarks that might apply to both cancer and wound healing and discuss how wounding, as in biopsy and surgery, might positively or negatively influence cancer in the clinic.

Receptor Tyrosine Kinases in Osteosarcoma Treatment: Which Is the Key Target?

Recent clinical trials have shown several multi-target tyrosine kinase inhibitors (TKIs) to be effective in the treatment of osteosarcoma. However, these TKIs have a number of targets, and it is yet unclear which of these targets has a key role in osteosarcoma treatment. In this review, we first summarize the TKIs that were studied in clinical trials registered on ClinicalTrials.gov. Further, we compare and discuss the targets of these TKIs. We found that TKIs with promising therapeutic effect for osteosarcoma include apatinib, cabozantinib, lenvatinib, regorafenib, and sorafenib. The key targets for osteosarcoma treatment may include VEGFRs and RET. The receptor tyrosine kinases (RTKs) MET, IGF-1R, AXL, PDGFRs, KIT, and FGFRs might be relevant but unimportant targets for osteosarcoma treatment. Inhibition of one type of RTK for the treatment of osteosarcoma is not effective. It is necessary to inhibit several relevant RTKs simultaneously to achieve a breakthrough in osteosarcoma treatment. This review provides comprehensive information on TKI targets relevant in osteosarcoma treatment, and it will be useful for further research in this field.

The role of tumor-stroma interactions on desmoplasia and tumorigenicity within a microengineered 3D platform

The tumor microenvironment has been demonstrated to play a crucial role in modulating cancer progression. Amongst various cell types within the tumor microenvironment, cancer associated fibroblasts (CAFs) are in abundance, serving to modulate the biophysical properties of the stromal matrix, through excessive deposition of extracellular matrix (ECM) proteins that leads to enhanced tumor progression. There is still a critical need to develop a fundamental framework on the role of tumor-stromal cell interactions on desmoplasia and tumorigenicity. Herein, we developed a 3D microengineered organotypic tumor-stroma model incorporated with breast cancer cells surrounded by CAF-embedded collagen matrix. We further integrated our platform with atomic force microscopy (AFM) to study the dynamic changes in stromal stiffness during active tumor invasion. Our findings primarily demonstrated enhanced tumor progression in the presence of CAFs. Furthermore, we highlighted the crucial role of crosstalk between tumor cells and CAFs on stromal desmoplasia, where we identified the role of tumor-secreted PDGF-AA/-BB on elevated matrix stiffness. Inhibition of the activity of PDGFRs in CAFs led to attenuation of stromal stiffness. Overall, our work presents a well-controlled tumor microenvironment model capable of dissecting specific biophysical and biochemical signaling cues which lead to stromal desmoplasia and tumor progression.

Impact of Epithelial-Stromal Interactions on Peritumoral Fibroblasts in Ductal Carcinoma in Situ

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.

Biological responses induced by high molecular weight chitosan administrated jointly with Platelet-derived Growth Factors in different mammalian cell lines

In this work, we studied cellular responses known to be involved in tissue regeneration, such as proliferation, migration and tubulogenesis under High Molecular Weight Chitosan (HMWC) and recombinant Platelet-derived Growth Factor (PDGF) treatments using an in vitro cell culture approach. We also analysed changes in mitochondrial dynamics that could be associated with such biological responses. For this proposes, endothelial human cell lines (EA.hy926 and ECFC) and 3T3-L1 mouse fibroblasts were used. The intracellular uptake of HMWC and their co-localization with acidic compartments were evaluated. Our results show that HMWC enhance PDGF-induced proliferation and cell migration in 3T3-L1 fibroblasts. An increase in PDGF-induced mitochondrial fragmentation was observed in 3T3-L1 cell line, but not in EA.hy926 cells, after the addition of HMWC. Endothelial cells, EA.hy926 and ECFC, potentiate their tubulogenesis capacity with the only addition of HMWC. The HMWC/PDGF-BB treatment notably enhanced tubule formation showing a synergistic effect when act combined in cell culture medium. The knowledge of these cellular responses can be used to design new tissue repair strategies using HMWC and PDGF.

ImmunoPET: Concept, Design, and Applications

Immuno-positron emission tomography (immunoPET) is a paradigm-shifting molecular imaging modality combining the superior targeting specificity of monoclonal antibody (mAb) and the inherent sensitivity of PET technique. A variety of radionuclides and mAbs have been exploited to develop immunoPET probes, which has been driven by the development and optimization of radiochemistry and conjugation strategies. In addition, tumor-targeting vectors with a short circulation time (e.g., Nanobody) or with an enhanced binding affinity (e.g., bispecific antibody) are being used to design novel immunoPET probes. Accordingly, several immunoPET probes, such as 89Zr-Df-pertuzumab and 89Zr-atezolizumab, have been successfully translated for clinical use. By noninvasively and dynamically revealing the expression of heterogeneous tumor antigens, immunoPET imaging is gradually changing the theranostic landscape of several types of malignancies. ImmunoPET is the method of choice for imaging specific tumor markers, immune cells, immune checkpoints, and inflammatory processes. Furthermore, the integration of immunoPET imaging in antibody drug development is of substantial significance because it provides pivotal information regarding antibody targeting abilities and distribution profiles. Herein, we present the latest immunoPET imaging strategies and their preclinical and clinical applications. We also emphasize current conjugation strategies that can be leveraged to develop next-generation immunoPET probes. Lastly, we discuss practical considerations to tune the development and translation of immunoPET imaging strategies.

Overexpression of Platelet-Derived Growth Factor and Its Receptor Are Correlated with Oral Tumorigenesis and Poor Prognosis in Oral Squamous Cell Carcinoma

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.

Anti-Proliferative Role of the Tyrosine Kinase Inhibitors TKI-258 on Oral Squamous Cell Carcinoma In Vitro

BACKGROUND

Identification of the antitumor role of tyrosine kinase inhibitors, such as TKI-258, may lead to novel therapeutics for Oral Squamous Cell Carcinoma (OSCC), which has high mortality rates. TKI-258 blocks Fibroblast Growth Factor Receptors (FGFRs), Platelet-Derived Growth Factor Receptors (PDGFRs), and Endothelial Growth Factor Receptor (VEGFRs).

OBJECTIVE

This study aimed to evaluate the effect of TKI-258 treatment on cell proliferation in SCC-4 cells of OSCC.

METHODS

BrdU and KI-67 assays were performed by using SCC-4 cells. Control was compared to 1, 5 and 10μM TKI-258 treatment. Control vehicle was compared to: 60μM LY294002 (LY), 2μM Wortmannin (WTN) and LY+WNT. Moreover, TKI 5μM treatment was compared to: TKI 5μM+LY; TKI 5 μM+WTN; TKI 5μM+LY+WTN. After 6h of treatments, immunofluorescence stained BrdU and KI-67 positive cells. Morphometry of proliferative cells was analyzed considering significance of p<0.05.

RESULTS

BrdU and KI-67 assays results were similar for all experiments. TKI-258 treatment leads to an important reduction in proliferation rate in SCC-4 cells in a concentration dependent manner. As expected, there was a significant reduction in the percentage of proliferative cells that had PI3K inhibited. When compared with TKI 5 treatment, proliferating cells were significantly lower with simultaneous PI3K inhibition.

CONCLUSION

This study demonstrated that TKI-258 plays an anti-proliferative role on SCC-4 cells of OSCC. It could be interesting to block multiples pathways such as FGFRs, PDGFRs and VEGFRs. Therefore, TKI-258 is a promising option for novel therapeutics for OSCC, especially if associated with PI3K inhibition.

Acute Treatment With Gleevec Does Not Promote Early Vascular Recovery Following Intracerebral Hemorrhage in Adult Male Rats

Intracerebral hemorrhage (ICH) remains one of the most debilitating types of stroke and is characterized by a sudden bleeding from a ruptured blood vessel. ICH often results in high mortality and in survivors, permanent disability. Most studies have focused on neuroprotective strategies designed to minimize secondary consequences and prevent further pathology. Lacking is an understanding of how ICH acutely affects cerebrovascular components and their response to therapeutic interventions. We hypothesized that ICH alters cortical vessel complexity in the parenchyma adjacent to site of the initial vascular disruption and that vascular abnormalities would be mitigated by administration of the PDGFR inhibitor, Imatinib mesylate (Gleevec). Briefly, ICH was induced in male adult rats by injection of collagenase into basal ganglia, followed by Gleevec administration (60 mg/kg) 1 h after injury. Rats were then perfused using vessel painting methodology (Salehi et al., 2018b) to stain whole brain vascular networks at 1 day post-ICH. Axial and coronal wide field fluorescence microscopy was performed. Analyses for vascular features were undertaken and fractal analysis for vascular complexity. Data were collected from four groups of rats: Sham + Vehicle; Sham + Gleevec; ICH + Vehicle; ICH + Gleevec. Microscopy revealed that cortical vessels in both ipsi- and contralateral hemispheres exhibited significantly reduced density and branching by 22 and 34%, respectively. Fractal measures confirmed reduced complexity as well. Gleevec treatment further reduced vascular parameters, including reductions in vessel density in tissues adjacent to the ICH. The reductions in brain wide vascular networks after Gleevec in the current study after ICH is contrasted by previous reports of improved behavioral outcomes and decreased lCH lesion volumes Reductions in the vascular network after Gleevec may be involved in long-term repair mechanisms by pruning injured vessels to ultimately promote new vessel growth.

Specific targeting of PDGFRβ in the stroma inhibits growth and angiogenesis in tumors with high PDGF-BB expression

PDGF-BB/PDGFRβ signaling plays an important role during vascularization by mediating pericyte recruitment to the vasculature, promoting the integrity and function of vessels. Until now it has not been possible to assess the specific role of PDGFRβ signaling in tumor progression and angiogenesis due to lack of appropriate animal models and molecular tools.

Methods: In the present study, we used a transgenic knock-in mouse strain carrying a silent mutation in the PDGFRβ ATP binding site that allows specific targeting of PDGFRβ using the compound 1-NaPP1. To evaluate the impact of selective PDGFRβ inhibition of stromal cells on tumor growth we investigated four tumor cell lines with no or low PDGFRβ expression, i.e. Lewis lung carcinoma (LLC), EO771 breast carcinoma, B16 melanoma and a version of B16 that had been engineered to overexpress PDGF-BB (B16/PDGF-BB).

Results: We found that specific impairment of PDGFRβ kinase activity by 1-NaPP1 treatment efficiently suppressed growth in tumors with high expression of PDGF-BB, i.e. LLC and B16/PDGF-BB, while the clinically used PDGFRβ kinase inhibitor imatinib did not suppress tumor growth. Notably, tumors with low levels of PDGF-BB, i.e. EO771 and B16, neither responded to 1-NaPP1 nor to imatinib treatment. Inhibition of PDGFRβ by either drug impaired tumor vascularization and also affected pericyte coverage; however, specific targeting of PDGFRβ by 1-NaPP1 resulted in a more pronounced decrease in vessel function with increased vessel apoptosis in high PDGF-BB expressing tumors, compared to treatment with imatinib. In vitro analysis of PDGFRβ ASKA mouse embryo fibroblasts and the mesenchymal progenitor cell line 10T1/2 revealed that PDGF-BB induced NG2 expression, consistent with the in vivo data.

Conclusion: Specific targeting of PDGFRβ signaling significantly inhibits tumor progression and angiogenesis depending on PDGF-BB expression. Our data suggest that targeting PDGFRβ in the tumor stroma could have therapeutic value in patients with high tumor PDGF-BB expression.

siRNA- and miRNA-based therapeutics for liver fibrosis

Liver fibrosis is a wound-healing process induced by chronic liver injuries, such as nonalcoholic steatohepatitis, hepatitis, alcohol abuse, and metal poisoning. The accumulation of excessive extracellular matrix (ECM) in the liver is a key characteristic of liver fibrosis. Activated hepatic stellate cells (HSCs) are the major producers of ECM and therefore play irreplaceably important roles during the progression of liver fibrosis. Liver fibrogenesis is highly correlated with the activation of HSCs, which is regulated by numerous profibrotic cytokines. Using RNA interference to downregulate these cytokines in activated HSCs is a promising strategy to reverse liver fibrosis. Meanwhile, microRNAs (miRNAs) have also been exploited for the treatment of liver fibrosis. This review focuses on the current siRNA- and miRNA-based liver fibrosis treatment strategies by targeting activated HSCs in the liver.

Cellular signalling by primary cilia in development, organ function and disease

Primary cilia project in a single copy from the surface of most vertebrate cell types; they detect and transmit extracellular cues to regulate diverse cellular processes during development and to maintain tissue homeostasis. The sensory capacity of primary cilia relies on the coordinated trafficking and temporal localization of specific receptors and associated signal transduction modules in the cilium. The canonical Hedgehog (HH) pathway, for example, is a bona fide ciliary signalling system that regulates cell fate and self-renewal in development and tissue homeostasis. Specific receptors and associated signal transduction proteins can also localize to primary cilia in a cell type-dependent manner; available evidence suggests that the ciliary constellation of these proteins can temporally change to allow the cell to adapt to specific developmental and homeostatic cues. Consistent with important roles for primary cilia in signalling, mutations that lead to their dysfunction underlie a pleiotropic group of diseases and syndromic disorders termed ciliopathies, which affect many different tissues and organs of the body. In this Review, we highlight central mechanisms by which primary cilia coordinate HH, G protein-coupled receptor, WNT, receptor tyrosine kinase and transforming growth factor-β (TGFβ)/bone morphogenetic protein (BMP) signalling and illustrate how defects in the balanced output of ciliary signalling events are coupled to developmental disorders and disease progression.

NRP-1 and KDR polymorphisms are associated with survival time in patients with advanced gastric cancer

Neuropilin-1 (NRP-1), a member of the NRP-family, has been reported to be vital for tumor angiogenesis, growth and metastasis. As a co-receptor of vascular endothelial growth factor (VEGF), NRP-1 can bind to VEGF and meditate vascular development through the VEGF-VEGF receptor 2 (VEGFR2) signaling pathway. Furthermore, NRP-1 is capable of binding with platelet-derived growth factor (PDGF) to regulate the PDGF-PDGF receptor (PDGR) signaling pathway in tumor angiogenesis. In the present study, The DNA was obtained from the paraffin-embedded tissues of patients with advanced gastric cancer (AGC), amplified using PCR and subsequently sequenced to determine the polymorphisms within NRP-1, VEGFR2 [kinase insert domain receptor (KDR)] and PDGF. The effect of the functional polymorphism of the aforementioned genes on the overall survival (OS) and progression-free survival (PFS) of 81 patients with advanced gastric cancer was examined. Three single nucleotide polymorphisms (SNPs) of KDR were significantly associated with clinical outcomes. The rs1870377 TT genotype was positively associated with longer OS and PFS times compared with the AA+AT genotype (PFS, P=0.012; OS, P=0.038), the rs7692791 wild-type TT genotype was positively associated with longer PFS time and the rs2034965 AA+GA genotype was associated with shorter OS time (P=0.034). With regards to the SNPs of NRP-1, the rs2065364 AA genotype was significantly associated with improved OS and PFS times (PFS, P=0.023; OS, P=0.045). Following multivariate analysis using Cox proportional hazards regression models, patients with the KDR rs7692791 TT genotype experienced a longer PFS time compared with those with the CT genotype (P=0.016), and patients with the NRP-1 rs2065364 variant-type AA genotype still experienced a longer PFS time compared with those patients with the AG+GG genotypes (P=0.006). Regarding OS, the results demonstrated that the KDR rs2034965 AG+GG genotypes presented with a significant reduction in OS time (P=0.029), and that the KDR rs1870377 AT+AA genotypes had worse OS times compared with the wild-type TT genotype (P=0.021). In addition, increased mortality risk and AGC progression were significantly associated with the number of adverse alleles for combinations of NRP-1 rs2065364 and KDR rs1870377. In conclusion, the data from the present study demonstrated that the selected KDR and NRP-1 gene polymorphisms may be potential prognostic biomarkers in AGC.

SPARC promotes the proliferation and metastasis of oral squamous cell carcinoma by PI3K/AKT/PDGFB/PDGFRβ axis

Oral squamous cell carcinoma (OSCC) is a highly lethal cancer in the world, and the prognosis of OSCC is poor with a 60% 5-year survival rate in recent decades. Here, we introduced a novel secretory and acid glycoprotein with cysteine rich (secreted protein acidic and rich in cysteine, SPARC), which is correlated with the worst pattern of invasion (WPOI) and prognosis of OSCC. SPARC expression levels were measured in OSCC tissues and normal tissues using quantitative polymerase chain reaction and immunohistochemistry. The influence of SPARC on cell proliferation was examined by cell counting kit-8, colony formation, and Edu tests. Then, the effect of SPARC on the metastasis of OSCC cells was detected by wound healing and transwell migration assays. Next, the biologic characteristics of SPARC shared by STRING were analyzed. Furthermore, the underlying mechanisms were confirmed by western blot analysis. SPARC revealed higher expression in OSCC tissues than nontumor tissues. Higher SPARC expression was correlated with poorer tumor differentiation, poorer WPOI pattern, and significantly and shorter overall survival. Knockdown SPARC significantly restrained OSCC cell growth, migration, and invasion. In addition, bioinformatics analysis found SPARC had a coexpression network with the platelet-derived growth factor-B (PDGFB) and PI3K/AKT signaling pathways with minimal false discovery rate. Furthermore, SPARC promotes OSCC cells metastasis by regulating the expressions of PDGFB, PDGFRβ, p-PDGFRβ , and the PI3K/AKT pathway. Higher SPARC expression was positively correlated with poor WPOI and differentiation in OSCC. SPARC activates the PI3K/AKT/PDGFB/PDGFRβ axis to promote proliferation and metastasis by OSCC cell lines. Therefore, SPARC may be a potential therapeutic target for patients with OSCC.

Role of tumor-derived exosomes in bone metastasis

Tight coupling between bone resorption and formation is essential for bone remodeling. Disruption of this equilibrium can lead to skeletal disorders. Osseous metastatic disease is a severe consequence of tumor cell dissemination from numerous primary cancer sites, including the prostate, lungs and breasts. Metastatic disease is one of the most common causes of mortality in patients with cancer. Rapid advances in the therapeutic options for bone disease, including the use of bisphosphonates, have achieved effective clinical effects. However, the overall survival time of patients with bone metastatic has not significantly improved. Exosomes, which originate from tumor tissue and preferentially the bone, provide a reasonable way to understand the mechanism of neoplastic bone metastasis. Recently, several studies have indicated that tumor-derived exosomes are involved in cancer progression. However, the potential role that exosomes serve in the pathological communication between tumor and bone cells within the skeletal microenvironment remains an emerging field. The present review reports some recent findings on the detrimental roles of exosomes in bone metastasis. In addition, since exosomes are involved in metabolic organ cross-talk, this review highlights the involvement of cancer-derived exosomes in the regulation of skeletal metastatic diseases. Lastly, the potential promising clinical applications and emerging therapeutic opportunities targeting exosomes are discussed as novel strategies for cancer therapy.

IGF2/IGF1R Signaling as a Therapeutic Target in MYB-Positive Adenoid Cystic Carcinomas and Other Fusion Gene-Driven Tumors

Chromosome rearrangements resulting in pathogenetically important gene fusions are a common feature of many cancers. They are often potent oncogenic drivers and have key functions in central cellular processes and pathways and encode transcription factors, transcriptional co-regulators, growth factor receptors, tyrosine kinases, and chromatin modifiers. In addition to being useful diagnostic biomarkers, they are also targets for development of new molecularly targeted therapies. Studies in recent decades have shown that several oncogenic gene fusions interact with the insulin-like growth factor (IGF) signaling pathway. For example, the MYB-NFIB fusion in adenoid cystic carcinoma is regulated by IGF1R through an autocrine loop, and IGF1R is a downstream target of the EWSR1-WT1 and PAX3-FKHR fusions in desmoplastic small round cell tumors and alveolar rhabdomyosarcoma, respectively. Here, we will discuss the mechanisms behind the interactions between oncogenic gene fusions and the IGF signaling pathway. We will also discuss the role of therapeutic inhibition of IGF1R in fusion gene driven malignancies.

Cancer-associated fibroblasts in desmoplastic tumors: emerging role of integrins

The tumor microenvironment (TME) is a complex meshwork of extracellular matrix (ECM) macromolecules filled with a collection of cells including cancer-associated fibroblasts (CAFs), blood vessel associated smooth muscle cells, pericytes, endothelial cells, mesenchymal stem cells and a variety of immune cells. In tumors the homeostasis governing ECM synthesis and turnover is disturbed resulting in abnormal blood vessel formation and excessive fibrillar collagen accumulations of varying stiffness and organization. The disturbed ECM homeostasis opens up for new types of paracrine, cell-cell and cell-ECM interactions with large consequences for tumor growth, angiogenesis, metastasis, immune suppression and resistance to treatments. As a main producer of ECM and paracrine signals the CAF is a central cell type in these events. Whereas the paracrine signaling has been extensively studied in the context of tumor-stroma interactions, the nature of the numerous integrin-mediated cell-ECM interactions occurring in the TME remains understudied. In this review we will discuss and dissect the role of known and potential CAF interactions in the TME, during both tumorigenesis and chemoresistance-induced events, with a special focus on the "interaction landscape" in desmoplastic breast, lung and pancreatic cancers. As an example of the multifaceted mode of action of the stromal collagen receptor integrin α11β1, we will summarize our current understanding on the role of this CAF-expressed integrin in these three tumor types.

Targeting Tyrosine kinases in Renal Cell Carcinoma: "New Bullets against Old Guys"

Clear cell renal cell carcinoma (ccRCC) is the seventh most frequently diagnosed tumor in adults in Europe and represents approximately 2.5% of cancer deaths. The molecular biology underlying renal cell carcinoma (RCC) development and progression has been a key milestone in the management of this type of tumor. The discovery of Von Hippel Lindau (VHL) gene alterations that arouse in 50% of ccRCC patients, leads the identification of an intracellular accumulation of HIF and, consequently an increase of VEGFR expression. This change in cell biology represents a new paradigm in the treatment of metastatic renal cancer by targeting angiogenesis. Currently, there are multiple therapeutic drugs available for advanced disease, including therapies against VEGFR with successful results in patients´ survival. Other tyrosine kinases' pathways, including PDGFR, Axl or MET have emerged as key signaling pathways involved in RCC biology. Indeed, promising new drugs targeting those tyrosine kinases have exhibited outstanding efficacy. In this review we aim to present an overview of the central role of these tyrosine kinases' activities in relevant biological processes for kidney cancer and their usefulness in RCC targeted therapy development. In the immunotherapy era, angiogenesis is still an "old guy" that the medical community is trying to fight using "new bullets".

Dynamin inhibitors impair platelet-derived growth factor β-receptor dimerization and signaling

The role of plasma membrane composition and dynamics in the activation process of receptor tyrosine kinases (RTKs) is still poorly understood. In this study we have investigated how signaling via the RTK, platelet-derived growth factor β-receptor (PDGFR-β) is affected by Dynasore or Dyngo-4a, which are commonly used dynamin inhibitors. PDGFR-β preferentially internalizes via clathrin-coated pits and in this pathway, Dynamin II has a major role in the formation and release of vesicles from the plasma membrane by performing the membrane scission. We have found that dynamin inhibitors impedes the activation of PDGFR-β by impairing ligand-induced dimerization of the receptor monomers, which leads to a subsequent lack of phosphorylation and activation both of receptors and downstream effectors, such as ERK1/2 and AKT. In contrast, dynamin inhibitors did not affect epidermal growth factor receptor (EGFR) dimerization and phosphorylation. Our findings suggest that there is a link between plasma membrane dynamics and PDGFR-β activation, and that this link is not shared with the epidermal growth factor receptor.

Hypoxia promotes osteosarcoma cell proliferation and migration through enhancing platelet-derived growth factor-BB/platelet-derived growth factor receptor-β axis

Osteosarcoma is a primary malignant bone tumor, characterized by high therapeutic resistance and poor outcomes, due to unclear pathological mechanisms. It has been shown recently that the platelet-derived growth factor (PDGF)/platelet-derived growth factor receptor (PDGFR) pathway is closely associated with the pathogenesis of osteosarcoma. Hypoxia is a critical hallmark of tumor microenvironment that promotes the malignant phenotype in many solid tumors and a fundamental impediment to effective tumor therapy. In this study, we confirmed that hypoxia is an important feature of osteosarcoma, validated by the positive immunohistochemistry staining of hypoxia marker hypoxia-inducible factor-1α (HIF-1α) and carbonic anhydrase IX (CAIX) in osteosarcoma tissue samples. More importantly, we discovered that hypoxia could transcriptionally upregulate the expression of both PDGF-BB and PDGFR-β in osteosarcoma cells in vitro. Likewise, we also established that hypoxia-induced PDGF-BB is strongly related to the enhanced cell proliferation and migration, by activating AKT, ERK1/2, and STAT3 signaling pathways. Notably, when using an antibody to block the autocrine of PDGF-BB, cell proliferation and migration were partially aborted in hypoxia. Collectively, we demonstrated that the hypoxia-activated PDGF-BB/PDGFR-β axis plays essential roles in osteosarcoma progression. These findings may shed light on the molecular pathogenesis of osteosarcoma, and provide a novel strategy for osteosarcoma treatment by combinational targeting hypoxia and PDGF-BB/PDGFR signaling.