Sprouting strategies and dead ends in anti-angiogenic targeting of NETs

Neuroendocrine tumors (NETs) are a heterogeneous group of neoplasms that arise from cells of the neuroendocrine system. NETs are characterized by being highly vascularized tumors that produce large amounts of proangiogenic factors. Due to their complexity and heterogeneity, progress in the development of successful therapeutic approaches has been limited. For instance, standard chemotherapy-based therapies have proven to be poorly selective for tumor cells and toxic for normal tissues. Considering the urge to develop an efficient therapy to treat NET patients, vascular targeting has been proposed as a new approach to block tumor growth. This review provides an update of the mechanisms regulating different components of vessels and their contribution to tumor progression in order to develop new therapeutic drugs. Following the description of classical anti-angiogenic therapies that target VEGF pathway, new angiogenic targets such as PDGFs, EGFs, FGFs and semaphorins are further explored. Based on recent research in the field, the combination of therapies that target multiple and different components of vessel formation would be the best approach to specifically target NETs and inhibit tumor growth.

Transfer and Expression of the Interferon Gamma Gene in Human Endothelial Cells Inhibits Vascular Smooth Muscle Cell Growth in Vitro

Intimal hyperplasia in blood vessels is primarily caused by the migration and proliferation of vascular smooth muscle cells. Excessive intimal thickening characterizes atherosclerosis as well as bypass graft and angioplasty failures. Endothelial cell-smooth muscle cell interactions and local cytokine production are important regulators of smooth muscle cell growth. Interferon gamma (γ-IFN), a product of T lymphocytes found in atherosclerotic lesions, inhibits smooth muscle cell proliferation in vitro. To determine if local delivery of γ-IFN may be useful in the treatment or prevention of vascular proliferative diseases, we transferred the human γ-IFN gene into endothelial cells isolated from human arteries and microvessels using a retroviral vector. Biologically active γ-IFN was produced and secreted by γ-IFN transduced endothelial cells, but not by control, nontransduced cells, or cells identically transduced with E. coli beta galactosidase (β-gal). To more closely approximate the microenvironment of blood vessels, subconfluent smooth muscle cells were plated in coculture with control, nontransduced endothelial cells, γ-IFN transduced endothelial cells, or β-gal transduced endothelial cells. Smooth muscle cell growth was inhibited 30-70% by coculture with γ-IFN transduced endothelial cells compared to coculture with β-gal transduced or control endothelial cells (p < 0.05). Our results suggest endothelial cells modified to produce γ-IFN may be a useful therapy in proliferative vascular diseases. Copyright © 1997 Elsevier Science Inc.

First Insights into Human Fingertip Regeneration by Echo-Doppler Imaging and Wound Microenvironment Assessment

Fingertip response to trauma represents a fascinating example of tissue regeneration. Regeneration derives from proliferative mesenchymal cells (blastema) that subsequently differentiate into soft and skeletal tissues. Clinically, conservative treatment of the amputated fingertip under occlusive dressing can shift the response to tissue loss from a wound repair process towards regeneration. When analyzing by Immunoassay the wound exudate from occlusive dressings, the concentrations of brain-derived neurotrophic factor (BDNF) and leukemia inhibitory factor (LIF) were higher in fingertip exudates than in burn wounds (used as controls for wound repair versus regeneration). Vascular endothelial growth factor A (VEGF-A) and platelet-derived growth factor (PDGF) were highly expressed in both samples in comparable levels. In our study, pro-inflammatory cytokines were relatively higher expressed in regenerative fingertips than in the burn wound exudates while chemokines were present in lower levels. Functional, vascular and mechanical properties of the regenerated fingertips were analyzed three months after trauma and the data were compared to the corresponding fingertip on the collateral uninjured side. While sensory recovery and morphology (pulp thickness and texture) were similar to uninjured sides, mechanical parameters (elasticity, vascularization) were increased in the regenerated fingertips. Further studies should be done to clarify the importance of inflammatory cells, immunity and growth factors in determining the outcome of the regenerative process and its influence on the clinical outcome.

Hypoxia-activated prodrug TH-302 decreased survival rate of canine lymphoma cells under hypoxic condition

We tested the hypotheses that hypoxic stimulation enhances growth potentials of canine lymphoma cells by activating hypoxia-inducible factor 1α (HIF-1α), and that the hypoxia-activated prodrug (TH-302) inhibits growth potentials in the cells. We investigated how hypoxic culture affects the growth rate, chemoresistance, and invasiveness of canine lymphoma cells and doxorubicin (DOX)-resistant lymphoma cells, and influences of TH-302 on survival rate of the cells under hypoxic conditions. Our results demonstrated that hypoxic culture upregulated the expression of HIF-1α and its target genes, including ATP-binding cassette transporter B1 (ABCB1), ATP-binding cassette transporter G2 (ABCG2), platelet-derived growth factor (PDGF), vascular endothelial growth factor (VEGF), and survivin, and enhanced the growth rate, DOX resistance, and invasiveness of the cells. Additionally, TH-302 decreased the survival rate of the cells under hypoxic condition. Our studies suggest that hypoxic stimulation may advance the tumorigenicity of canine lymphoma cells, favoring malignant transformation. Therefore, the data presented may contribute to the development of TH-302-based hypoxia-targeting therapies for canine lymphoma.

PDGF-D promotes cell growth, aggressiveness, angiogenesis and EMT transformation of colorectal cancer by activation of Notch1/Twist1 pathway

Platelet-derived growth factor-D (PDGF-D) plays a crucial role in the progression of several cancers. However, its role in colorectal cancer (CRC) remains unclear. Our study showed that PDGF-D was highly expressed in CRC tissues and was positively associated with the clinicopathological features. Down-regulation of PDGF-D inhibited the tumor growth, migration and angiogenesis of SW480 cells in vitro and in vivo. Whereas up-regulation of PDGF-D promoted the malignant behaviors of HCT116 cells. Moreover, PDGF-D up-regulated the expression of Notch1 and Twist1 in CRC cells. In addition, PDGF-D expression promoted Epithelial to mesenchymal transition (EMT), which was accompanied with decreased E-cadherin and increased Vimentin expression. Consistently, PDGF-D, Notch1, and Twist1 are obviously up-regulated in transforming growth factor-beta 1 (TGF-β1) treated HCT116 cells. Since Notch1 and Twist1 play an important role in EMT and tumor progression, we examined whether there is a correlation between Notch1 and Twist1 in EMT status. Our results showed that up-regulation of Notch1 was able to rescue the effects of PDGF-D down-regulation on Twist1 expression in SW480 cells, whereas down-regulation of Notch1 reduced Twist1 expression in HCT116 cells. Furthermore, we found that Twist1 promoted EMT and aggressiveness of CRC cells. These results suggest that PDGF-D promotes tumor growth and aggressiveness of CRC, moreover, down-regulation of PDGF-D inactivates Notch1/Twist1 axis, which could reverse EMT and prevent CRC progression.

Pathway Analysis of Skin from Psoriasis Patients after Adalimumab Treatment Reveals New Early Events in the Anti-Inflammatory Mechanism of Anti-TNF-α

Psoriasis is a chronic cutaneous inflammatory disease. The immunopathogenesis is a complex interplay between T cells, dendritic cells and the epidermis in which T cells and dendritic cells maintain skin inflammation. Anti-tumour necrosis factor (anti-TNF)-α agents have been approved for therapeutic use across a range of inflammatory disorders including psoriasis, but the anti-inflammatory mechanisms of anti-TNF-α in lesional psoriatic skin are not fully understood. We investigated early events in skin from psoriasis patients after treatment with anti-TNF-α antibodies by use of bioinformatics tools. We used the Human Gene 1.0 ST Array to analyse gene expression in punch biopsies taken from psoriatic patients before and also 4 and 14 days after initiation of treatment with the anti-TNF-α agent adalimumab. The gene expression was analysed by gene set enrichment analysis using the Functional Annotation Tool from DAVID Bioinformatics Resources. The most enriched pathway was visualised by the Pathview Package on Kyoto Encyclopedia of Genes and Genomes (KEGG) graphs. The analysis revealed new very early events in psoriasis after adalimumab treatment. Some of these events have been described after longer periods of anti-TNF-α treatment when clinical and histological changes appear, suggesting that effects of anti-TNF-α treatment on gene expression appear very early before clinical and histological changes. Combining microarray data on biopsies from psoriasis patients with pathway analysis allowed us to integrate in vitro findings into the identification of mechanisms that may be important in vivo. Furthermore, these results may reflect primary effect of anti-TNF-α treatment in contrast to studies of gene expression changes following clinical and histological changes, which may reflect secondary changes correlated to the healing of the skin.

LIGHT (TNFSF14) Increases the Survival and Proliferation of Human Bone Marrow-Derived Mesenchymal Stem Cells

LIGHT (HVEM-L, TNFSF14, or CD258), an entity homologous to lymphotoxins, with inducible nature and the ability to compete with herpes simplex virus glycoprotein D for herpes virus entry mediator (HVEM)/tumor necrosis factor (TNF)-related 2, is a member of the TNF superfamily. It is expressed as a homotrimer on activated T cells and dendritic cells (DCs), and has three receptors: HVEM, LT-β receptor (LTβR), and decoy receptor 3 (DcR3). So far, three receptors with distinct cellular expression patterns are known to interact with LIGHT. Follicular DCs and stromal cells bind LIGHT through LTβR. We monitored the effects of LIGHT on human bone marrow-derived mesenchymal stem cells (BM-MSCs). At first, we checked the negative and positive differentiation markers of BM-MSCs. And we confirmed the quality of MSCs by staining cells undergoing adipogenesis (Oil Red O staining), chondrogenesis (Alcian blue staining), and osteogenesis (Alizarin red staining). After rhLIGHT treatment, we monitored the count, viability, and proliferation of cells and cell cycle distribution. PDGF and TGFβ production by rhLIGHT was examined by ELISA, and the underlying biological mechanisms were studied by immunoblotting by rhLIGHT treatment. LTβR was constitutively expressed on the surface of human BM-MSCs. Cell number and viability increased after rhLIGHT treatment. BM-MSC proliferation was induced by an increase in the S/G₂/M phase. The expression of not only diverse cyclins such as cyclin B1, D1, D3, and E, but also CDK1 and CDK2, increased, while that of p27 decreased, after rhLIGHT treatment. RhLIGHT-induced PDGF and TGFβ production mediated by STAT3 and Smad3 activation accelerated BM-MSC proliferation. Thus, LIGHT and LTβR interaction increases the survival and proliferation of human BM-MSCs, and therefore, LIGHT might play an important role in stem cell therapy.

Tadalafil Promotes the Recovery of Peripheral Neuropathy in Type II Diabetic Mice

We previously demonstrated that treatment of diabetic peripheral neuropathy with the short (4 hours) half-life phosphodiesterase 5 (PDE5) inhibitor, sildenafil, improved functional outcome in diabetic db/db mice. To further examine the effect of PDE5 inhibition on diabetic peripheral neuropathy, we investigated the effect of another potent PDE5 inhibitor, tadalafil, on diabetic peripheral neuropathy. Tadalafil is pharmacokinetically distinct from sildenafil and has a longer half-life (17+hours) than sildenafil. Diabetic mice (BKS.Cg-m+/+Lepr^db/J, db/db) at age 20 weeks were treated with tadalafil every 48 hours for 8 consecutive weeks. Compared with diabetic mice treated with saline, tadalafil treatment significantly improved motor and sensory conduction velocities in the sciatic nerve and peripheral thermal sensitivity. Tadalafil treatment also markedly increased local blood flow and the density of FITC-dextran perfused vessels in the sciatic nerve concomitantly with increased intraepidermal nerve fiber density. Moreover, tadalafil reversed the diabetes-induced reductions of axon diameter and myelin thickness and reversed the diabetes-induced increased g-ratio in the sciatic nerve. Furthermore, tadalafil enhanced diabetes-reduced nerve growth factor (NGF) and platelet-derived growth factor-C (PDGF-C) protein levels in diabetic sciatic nerve tissue. The present study demonstrates that tadalafil increases regional blood flow in the sciatic nerve tissue, which may contribute to the improvement of peripheral nerve function and the amelioration of diabetic peripheral neuropathy.

125I-labeled anti-bFGF monoclonal antibody inhibits growth of hepatocellular carcinoma

AIM: To investigate the inhibitory efficacy of ¹²⁵I-labeled anti-basic fibroblast growth factor (bFGF) monoclonal antibody (mAb) in hepatocellular carcinoma (HCC).

METHODS: bFGF mAb was prepared by using the 1G9B9 hybridoma cell line with hybridization technology and extracted from ascites fluid through a Protein G Sepharose affinity column. After labeling with ¹²⁵I through the chloramine-T method, bFGF mAb was further purified by a Sephadex G-25 column. Gamma radiation counter GC-1200 detected radioactivity of ¹²⁵I-bFGF mAb. The murine H22 HCC xenograft model was established and randomized to interventions with control (phosphate-buffered saline), ¹²⁵I-bFGF mAb, ¹²⁵I plus bFGF mAb, bFGF mAb, or ¹²⁵I. The ratios of tumor inhibition were then calculated. Expression of bFGF, fibroblast growth factor receptor (FGFR), platelet-derived growth factor, and vascular endothelial growth factor (VEGF) mRNA was determined by quantitative reverse transcriptase real-time polymerase chain reaction.

RESULTS: The purified bFGF mAb solution was 8.145 mg/mL with a titer of 1:2560000 and was stored at -20 °C. After coupling, ¹²⁵I-bFGF mAb was used at a 1: 1280000 dilution, stored at 4 °C, and its specific radioactivity was 37 MBq/mg. The corresponding tumor weight in the control, ¹²⁵I, bFGF mAb, ¹²⁵I plus bFGF mAb, and ¹²⁵I-bFGF mAb groups was 1.88 ± 0.25, 1.625 ± 0.21, 1.5 ± 0.18, 1.41 ± 0.16, and 0.98 ± 0.11 g, respectively. The tumor inhibition ratio in the ¹²⁵I, bFGF mAb, ¹²⁵I plus bFGF mAb, and ¹²⁵I-bFGF mAb groups was 13.6%, 20.2%, 25.1%, and 47.9%, respectively. Growth of HCC xenografts was inhibited significantly more in the ¹²⁵I-bFGF mAb group than in the other groups (P < 0.05). Expression of bFGF and FGFR mRNA in the ¹²⁵I-bFGF mAb group was significantly decreased in comparison with other groups (P < 0.05). Groups under interventions revealed increased expression of VEGF mRNA (except for ¹²⁵I group) compared with the control group.

CONCLUSION: ¹²⁵I-bFGF mAb inhibits growth of HCC xenografts. The coupling effect of ¹²⁵I-bFGF mAb is more effective than the concomitant use of ¹²⁵I and bFGF mAb.

Mice Lacking Platelet-Derived Growth Factor D Display a Mild Vascular Phenotype

Platelet-derived growth factor D (PDGF-D) is the most recently discovered member of the PDGF family. PDGF-D signals through PDGF receptor β, but its biological role remains largely unknown. In contrast to other members of the PDGF family of growth factors, which have been extensively investigated using different knockout approaches in mice, PDGF-D has until now not been characterized by gene inactivation in mice. Here, we present the phenotype of a constitutive Pdgfd knockout mouse model (Pdgfd^-/-), carrying a LacZ reporter used to visualize Pdgfd promoter activity. Inactivation of the Pdgfd gene resulted in a mild phenotype in C57BL/6 mice, and the offspring was viable, fertile and generally in good health. We show that Pdgfd reporter gene activity was consistently localized to vascular structures in both postnatal and adult tissues. The expression was predominantly arterial, often localizing to vascular bifurcations. Endothelial cells appeared to be the dominating source for Pdgfd, but reporter gene activity was occasionally also found in subpopulations of mural cells. Tissue-specific analyses of vascular structures revealed that NG2-expressing pericytes of the cardiac vasculature were disorganized in Pdgfd^-/- mice. Furthermore, Pdgfd^-/- mice also had a slightly elevated blood pressure. In summary, the vascular expression pattern together with morphological changes in NG2-expressing cells, and the increase in blood pressure, support a function for PDGF-D in regulating systemic arterial blood pressure, and suggests a role in maintaining vascular homeostasis.

Methylation Microarray Studies Highlight PDGFA Expression as a Factor in Biliary Atresia

Biliary atresia (BA) is a progressive fibro-inflammatory disorder that is the leading indication for liver transplantation in children. Although there is evidence implicating genetic, infectious, environmental, and inflammatory causes, the etiology of BA remains unknown. We have recently reported that cholangiocytes from BA patients showed decreased DNA methylation relative to disease- and non-disease controls, supporting a potential role for DNA hypomethylation in BA etiopathogenesis. In the current study, we examined the methylation status of specific genes in human BA livers using methylation microarray technology. We found global DNA hypomethylation in BA samples as compared to disease- and non-disease controls at specific genetic loci. Hedgehog pathway members, SHH and GLI2, known to be upregulated in BA, were both hypomethylated, validating this approach as an investigative tool. Another region near the PDGFA locus was the most significantly hypomethylated in BA, suggesting potential aberrant expression. Validation assays confirmed increased transcriptional and protein expression of PDGFA in BA livers. We also show that PDGF-A protein is specifically localized to cholangiocytes in human liver samples. Injection of PDGF-AA protein dimer into zebrafish larvae caused biliary developmental and functional defects. In addition, activation of the Hedgehog pathway caused increased expression of PDGF-A in zebrafish larvae, providing a previously unrecognized link between PDGF and the Hedgehog pathway. Our findings implicate DNA hypomethylation as a specific factor in mediating overexpression of genes associated with BA and identify PDGF as a new candidate in BA pathogenesis.

Canonical and non-canonical Wnt signaling control the regeneration of amputated rodent vibrissae follicles

Although mammals are notoriously poor at regeneration compared with many lower-order species, the hair follicle, particular to mammals, is capable of regeneration following partial amputation. The detailed internal mechanism of this phenomenon is still unclear. Development and regrowth of the hair follicle depends on dermal-epidermal interaction within the hair follicle. Previous studies have shown that Wnt/β-catenin, Shh, Bmp, PDGF, TGF and Notch signals all take part in the development and growth of the hair follicle, and the Wnt/β-catenin signaling additionally plays an indispensable role in hair follicle morphogenesis and regrowth. In this study, we investigated the localization, as well as, protein levels of Wnt/β-catenin signaling molecules during amputated whisker follicle regeneration.

The platelet-derived growth factors (PDGFs) and their receptors (PDGFRs) are major players in oncogenesis, drug resistance, and attractive oncologic targets in cancer

The platelet-derived growth factors (PDGFs) and their receptors (PDGFRs) play a key role in signaling pathways in oncogenesis. The overexpression of PDGFs and PDGFRs and the oncogenic alterations of these receptors have been implicated in human cancers and correlated significantly with poor outcomes. This review discusses the biology of the PDGF isoforms and receptors briefly, and their role in oncogenesis. Also, the attractiveness of targeting PDGFs and PDGFRs, based on a wide display of oncologic alterations in cancers, diverse therapeutic strategies, their roles in resistance to cancer treatments with prospects of overcoming drug resistance, and the extent to which validated biomarkers have been developed for effective PDGFs and PDGFRs-based cancer management are discussed.

Molecular mechanisms of extracellular vesicle-induced vessel destabilization in diabetic retinopathy

AIMS

Diabetic retinopathy (DR) is characterized by early dropout of capillary pericytes, leading to loss of control on endothelial proliferation and, subsequently, angiogenesis. We have demonstrated that extracellular vesicles (EV) derived from mesenchymal stem cells (MSC) maintained in diabetic-like conditions may play a role in vessel destabilization, thus contributing to angiogenesis through paracrine signalling. In particular, a role for MMP-2 was described. This study was aimed at further investigating the molecular mechanisms of EV-induced vessel destabilization.

METHODS

We evaluated miR-126 expression, the subsequent HIF-1α and VEGF modulation, Ang-2 and PDGF signalling pathways in human retinal pericytes (HRP) after exposure to MSC-derived EV obtained in diabetic-like conditions (high glucose and/or hypoxia).

RESULTS

HRP express miR-126, and this expression is down-regulated in intermittent high glucose. MSC-derived EV obtained in hyperglycaemic/hypoxic conditions down-regulate miR-126 expression in pericytes, leading to increased expression of angiogenic molecules, such as VEGF and HIF-1α. No modulation of Ang-2 and PDGF signalling pathways in pericytes was observed following EV exposure.

CONCLUSIONS

HRP express miR-126, and this expression is down-regulated in diabetic-like conditions. Exposure of HRP to EV obtained in diabetic-like conditions is able to decrease miR-126 expression, consistently with previous observations of its involvement in DR and providing further insights into the role of EV in vessel destabilization. In contrast, PDGF and Ang-2 signalling pathways do not seem to be involved in these mechanisms.

Is there a correlation between peripheral blood expression of angiogenic transcriptional factors/receptors and colorectal cancer?

PURPOSE

The aim of this study was to evaluate whether there is a correlation between peripheral blood expression of angiogenic transcriptional factors/receptors and colorectal cancer (CRC).

METHODS

Eighty six blood samples collected from patients with CRC (N=42), adenomas and/or hyperplastic polyps(AP, N=30) and individuals without colon pathology (control group/CTR, N=14) were used for this study. Twelve transcription factors and receptors were assessed by qRT-PCR in a case-control study. The molecules with a minimum of 30% differences in gene expression for CRC and AP compared to CTR were then analyzed separately for each sample. Gene expression was evaluated relatively to the CTR after normalization to the large ribosomal protein PO (RPLPO) housekeeping gene, and the differential expression between studied groups was assessed by ANOVA.

RESULTS

Seven out of 12 genes presented differences in expression between 10-29% in CRC and/or AP compared to CTR. Considering the selection criteria, we further individually evaluated the levels of expression of 5 genes that had a minimum of 30% expression in the case-control study. Our data showed a significant up-regulation of platelet derived growth factor (PDGF) C in the blood of the patients with CRC compared to CTR (p=0.007). Likewise, clusterin (CLU) was significantly up-regulated both in CRC and AP groups compared to healthy subjects (p=0.01). For VEGFR1, PDGFRA and TGFB1 we didn't find significantly differential expression between any of the studied groups, even if increased levels were observed in both CRC and AP vs CTR.

CONCLUSIONS

The results of our study indicated that increased blood level of PDGFC mRNA was associated with the presence of CRC (p=0.007). Additionally, high levels of circulating CLU mRNA were observed in both malignant and benign colorectal pathologies.

Deficiency of NOX1 or NOX4 Prevents Liver Inflammation and Fibrosis in Mice through Inhibition of Hepatic Stellate Cell Activation

Reactive oxygen species (ROS) produced by nicotinamide adenine dinucleotide phosphate oxidase (NOX) play a key role in liver injury and fibrosis. Previous studies demonstrated that GKT137831, a dual NOX1/4 inhibitor, attenuated liver fibrosis in mice as well as pro-fibrotic genes in hepatic stellate cells (HSCs) as well as hepatocyte apoptosis. The effect of NOX1 and NOX4 deficiency in liver fibrosis is unclear, and has never been directly compared. HSCs are the primary myofibroblasts in the pathogenesis of liver fibrosis. Therefore, we aimed to determine the role of NOX1 and NOX4 in liver fibrosis, and investigated whether NOX1 and NOX4 signaling mediates liver fibrosis by regulating HSC activation. Mice were treated with carbon tetrachloride (CCl₄) to induce liver fibrosis. Deficiency of either NOX1 or NOX4 attenuates liver injury, inflammation, and fibrosis after CCl₄ compared to wild-type mice. NOX1 or NOX4 deficiency reduced lipid peroxidation and ROS production in mice with liver fibrosis. NOX1 and NOX4 deficiency are approximately equally effective in preventing liver injury in the mice. The NOX1/4 dual inhibitor GKT137831 suppressed ROS production as well as inflammatory and proliferative genes induced by lipopolysaccharide (LPS), platelet-derived growth factor (PDGF), or sonic hedgehog (Shh) in primary mouse HSCs. Furthermore, the mRNAs of proliferative and pro-fibrotic genes were downregulated in NOX1 and NOX4 knock-out activated HSCs (cultured on plastic for 5 days). Finally, NOX1 and NOX4 protein levels were increased in human livers with cirrhosis compared with normal controls. Thus, NOX1 and NOX4 signaling mediates the pathogenesis of liver fibrosis, including the direct activation of HSC.

Release of Phosphorylated HSP27 (HSPB1) from Platelets Is Accompanied with the Acceleration of Aggregation in Diabetic Patients

We investigated the relationship between HSP27 phosphorylation and collagen-stimulated activation of platelets in patients with diabetes mellitus (DM). Platelet-rich plasma was prepared from blood of type 2 DM patients. The platelet aggregation was analyzed in size of aggregates by an aggregometer using a laser scattering method. The protein phosphorylation was analyzed by Western blotting. Phosphorylated-HSP27 and PDGF-AB released from platelets were measured by ELISA. The phosphorylated-HSP27 levels at Ser-78 and Ser-82 induced by collagen were directly proportional to the platelet aggregation. Total HSP27 levels in platelets were decreased concomitantly with the phosphorylation. The released HSP27 levels were significantly correlated with the phosphorylated levels of HSP27 in the platelets stimulated by 0.3 μg/ml collagen. The low dose collagen-stimulated release of HSP27 was detected but relatively small in healthy donors. The released levels of PDGF-AB were in parallel with the levels of released HSP27. Area under the curve (AUC) of small aggregation (9-25 μm) induced by 0.3 μg/ml collagen was inversely proportional to the levels of released HSP27. AUC of large aggregation (50-70 μm) was directly proportional to the levels of released HSP27. Exogenous recombinant phosphorylated- HSP27 hardly affected the aggregation or the released levels of PDGF-AB induced by collagen. These results strongly suggest that HSP27 is released from human platelets accompanied with its phosphorylation induced by collagen, which is correlated with the acceleration of platelet aggregation in type 2 DM patients.

Effect of 15-hydroxyprostaglandin dehydrogenase inhibitor on wound healing

PGE2 is an important mediator of wound healing. It is degraded and inactivated by 15-hydroxyprostaglandin dehydrogenase (15-PGDH). Various growth factors, type IV collagen, TIMP-2 and PGE2 are important mediators of inflammation involving wound healing. Overproduction of TGF-β and suppression of PGE2 are found in excessive wound scarring. If we make the condition downregulating growth factors and upregulating PGE2, the wound will have a positive effect which results in little scar formation after healing. TD88 is a 15-PGDH inhibitor based on thiazolinedione structure. We evaluated the effect of TD88 on wound healing. In 10 guinea pigs (4 control and 6 experimental groups), we made four 1cm diameter-sized circular skin defects on each back. TD88 and vehicle were applicated on the wound twice a day for 4 days in the experimental and control groups, respectively. Tissue samples were harvested for qPCR and histomorphometric analyses on the 2nd and 4th day after treatment. Histomorphometric analysis showed significant reepithelization in the experimental group. qPCR analysis showed significant decrease of PDGF, CTGF and TIMP-2, but significant increase of type IV collagen in the experimental group. Taken together TD88 could be a good effector on wound healing, especially in the aspects of prevention of scarring.

Targeting Angiogenesis in Cancer Therapy: Moving Beyond Vascular Endothelial Growth Factor

Angiogenesis, or the formation of new capillary blood vessels, occurs primarily during human development and reproduction; however, aberrant regulation of angiogenesis is also a fundamental process found in several pathologic conditions, including cancer. As a process required for invasion and metastasis, tumor angiogenesis constitutes an important point of control of cancer progression. Although not yet completely understood, the complex process of tumor angiogenesis involves highly regulated orchestration of multiple signaling pathways. The proangiogenic signaling molecule vascular endothelial growth factor (VEGF) and its cognate receptor (VEGF receptor 2 [VEGFR-2]) play a central role in angiogenesis and often are highly expressed in human cancers, and initial clinical efforts to develop antiangiogenic treatments focused largely on inhibiting VEGF/VEGFR signaling. Such approaches, however, often lead to transient responses and further disease progression because angiogenesis is regulated by multiple pathways that are able to compensate for each other when single pathways are inhibited. The platelet-derived growth factor (PDGF) and PDGF receptor (PDGFR) and fibroblast growth factor (FGF) and FGF receptor (FGFR) pathways, for example, provide potential escape mechanisms from anti-VEGF/VEGFR therapy that could facilitate resumption of tumor growth. Accordingly, more recent treatments have focused on inhibiting multiple signaling pathways simultaneously. This comprehensive review discusses the limitations of inhibiting VEGF signaling alone as an antiangiogenic strategy, the importance of other angiogenic pathways including PDGF/PDGFR and FGF/FGFR, and the novel current and emerging agents that target multiple angiogenic pathways for the treatment of advanced solid tumors.

IMPLICATIONS FOR PRACTICE

Significant advances in cancer treatment have been achieved with the development of antiangiogenic agents, the majority of which have focused on inhibition of the vascular endothelial growth factor (VEGF) pathway. VEGF targeting alone, however, has not proven to be as efficacious as originally hoped, and it is increasingly clear that there are many interconnected and compensatory pathways that can overcome VEGF-targeted inhibition of angiogenesis. Maximizing the potential of antiangiogenic therapy is likely to require a broader therapeutic approach using a new generation of multitargeted antiangiogenic agents.

Differential gene expression and immunolocalization of platelet-derived growth factors and their receptors in caprine ovaries

This study evaluated the messenger RNA (mRNA) expression and immunolocalization of all members of the platelet-derived growth factor (PDGF) family in caprine ovaries by quantitative PCR and immunohistochemistry, respectively. Detectable levels of PDGF-A mRNA were not observed in primordial follicles. Higher levels of PDGF-B mRNA were observed in primary follicles than in primordial follicles (P < 0.05). PDGF-D mRNA levels were higher in secondary follicles than in the other preantral follicle categories (P < 0.05). PDGF-B mRNA expression was higher than PDGF-C mRNA expression in primary follicles (P < 0.05). In antral follicles, PDGF-A mRNA expression was higher in cumulus-oocyte complexes (COCs) from small antral follicles than in those from large antral follicles and their respective granulosa/theca (GT) cells (P < 0.05). Furthermore, in COCs from small and large antral follicles, PDGF-A mRNA expression was higher than that of the other PDGF isoforms (P < 0.05). The mRNA levels of PDGF-B and PDGF-D and PDGFR-α and PDGFR-β were higher in GT cells from large antral follicles than in GT cells from small antral follicles and in their respective COCs (P < 0.05). In COCs and GT cells from small antral follicles, the mRNA levels of PDGFR-α were higher than those of PDGFR-β (P < 0.05). All proteins were observed in the cytoplasm of oocytes from all follicular categories. In granulosa cells, all PDGFs and PDGFR-β were detected from starting at the secondary stage, and in theca cells, all proteins, except PDGF-C, were detected starting at the antral stage. In conclusion, PDGF and its receptors are differentially expressed in the oocytes and ovarian cells according to the stage of follicular development, suggesting their role in the regulation of folliculogenesis in goats.

Hair-growth-promoting effect of conditioned medium of high integrin α6 and low CD 71 (α6bri/CD71dim) positive keratinocyte cells

Keratinocyte stem/progenitor cells (KSCs) reside in the bulge region of the hair follicles and may be involved in hair growth. Hair follicle dermal papilla cells (HFDPCs) and outer root sheath (ORS) cells were treated with conditioned medium (CM) of KSCs. Moreover, the effects of KSC-CM on hair growth were examined ex vivo and in vivo. A human growth factor chip array and RT-PCR were employed to identify enriched proteins in KSC-CM as compared with CM from keratinocytes. KSC-CM significantly increased the proliferation of HFDPCs and ORS cells, and increased the S-phase of the cell cycle in HFDPCs. KSC-CM led to the phosphorylation of ATK and ERK1/2 in both cell types. After subcutaneous injection of KSC-CM in C3H/HeN mice, a significant increase in hair growth and increased proliferation of hair matrix keratinocytes ex vivo was observed. We identified six proteins enriched in KSC-CM (amphiregulin, insulin-like growth factor binding protein-2, insulin-like growth factor binding protein-5, granulocyte macrophage-colony stimulating factor, Platelet-derived growth factor-AA, and vascular endothelial growth factor). A growth-factor cocktail that contains these six recombinant growth factors significantly increased the proliferation of HFDPCs and ORS cells and enhanced the hair growth of mouse models. These results collectively indicate that KSC-CM has the potential to increase hair growth via the proliferative capacity of HFDPCs and ORS cells.

Cyclophosphamide Combined with Bone Marrow Mesenchymal Stromal Cells Protects against Bleomycin-induced Lung Fibrosis in Mice

INTRODUCTION

To examine the effects and possible mechanism of the immunosuppressant agent cyclophosphamide (CP) combined with bone marrow mesenchymal stromal cells (BM-MSCs) on bleomycin induced lung fibrosis in mice.

METHODS

BM-MSCs labeled with red fluorescence protein (RFP) from male Friend virus B-type(FVB) mice were cultured in vitro. Pulmonary fibrosis(PF) was induced in female wild type FVB mice and mice were randomly divided into five groups: control, model, CP, BM-MSCs, and BM-MSCs+CP. Pathological changes and distribution of RFP (+) BMSC in lung tissue were observed and hydroxyproline (Hyp) content in the lungs was measured. Changes in TGF-β mRNA, PDGF mRNA, and SDF-1mRNA expression in lung tissue were measured.

RESULTS

PF and Hyp levels in the BM-MSCs and BM-MSCs+CP groups were significantly alleviated (p<0.01) compared to the model group. The RFP (+) cells were distributed in the periphery of the alveolar space and endomembrane of bronchus. Hyp levels were reduced in the BM-MSCs+CP group compared to the BM-MSCs group (p<0.05). TGF-β and PDGF levels in the BM-MSCs and BM-MSCs+CP groups were higher than in the control or model group (p<0.05). SDF-1 level in the CP group showed no significant differences compared to the control group, in the other groups were higher than in the control group (p<0.05) and in the BM-MSCs+CP group was lower than in the BM-MSCs group (p<0.05).

CONCLUSION

It was concluded that CP alone does not improve PF and may be harmful. In contrast, combined application of BM-MSCs with CP provided better protection against PF and may serve as an effective therapy.