HGF expression induced by HIF-1α promote the proliferation and tube formation of endothelial progenitor cells

Development of Hetero-Cell Type Spheroids Via Core-Shell Strategy for Enhanced Wound Healing Effect of Human Adipose-Derived Stem Cells

BACKGROUND

Stem cell-based therapies have been developed to treat various types of wounds. Human adipose-derived stem cells (hADSCs) are used to treat skin wounds owing to their outstanding angiogenic potential. Although recent studies have suggested that stem cell spheroids may help wound healing, their cell viability and retention rate in the wound area require improvement to enhance their therapeutic efficacy.

METHODS

We developed a core-shell structured spheroid with hADSCs in the core and human dermal fibroblasts (hDFs) in the outer part of the spheroid. The core-shell structure was formed by continuous centrifugation and spheroid incubation. After optimizing the method for inducing uniform-sized core-shell spheroids, cell viability, cell proliferation, migration, and therapeutic efficacy were evaluated and compared to those of conventional spheroids.

RESULTS

Cell proliferation, migration, and involucrin expression were evaluated in keratinocytes. Tubular assays in human umbilical vein endothelial cells were used to confirm the improved skin regeneration and angiogenic efficacy of core-shell spheroids. Core-shell spheroids exhibited exceptional cell viability under hypoxic cell culture conditions that mimicked the microenvironment of the wound area.

CONCLUSION

The improvement in retention rate, survival rate, and angiogenic growth factors secretion from core-shell spheroids may contribute to the increased therapeutic efficacy of stem cell treatment for skin wounds.

Hypoxia in Skin Cancer: Molecular Basis and Clinical Implications

Skin cancer is one of the most prevalent cancers in the Caucasian population. In the United States, it is estimated that at least one in five people will develop skin cancer in their lifetime, leading to significant morbidity and a healthcare burden. Skin cancer mainly arises from cells in the epidermal layer of the skin, where oxygen is scarce. There are three main types of skin cancer: malignant melanoma, basal cell carcinoma, and squamous cell carcinoma. Accumulating evidence has revealed a critical role for hypoxia in the development and progression of these dermatologic malignancies. In this review, we discuss the role of hypoxia in treating and reconstructing skin cancers. We will summarize the molecular basis of hypoxia signaling pathways in relation to the major genetic variations of skin cancer.

Hypoxia activated HGF expression in pancreatic stellate cells confers resistance of pancreatic cancer cells to EGFR inhibition

BACKGROUND

Epidermal growth factor receptor (EGFR) is an essential target for cancer treatment. However, EGFR inhibitor erlotinib showed limited clinical benefit in pancreatic cancer therapy. Here, we showed the underlying mechanism of tumor microenvironment suppressing the sensitivity of EGFR inhibitor through the pancreatic stellate cell (PSC).

METHODS

The expression of alpha-smooth muscle actin (α-SMA) and hypoxia marker in human pancreatic cancer tissues were detected by immunohistochemistry, and their correlation with overall survival was evaluated. Human immortalized PSC was constructed and used to investigate the potential effect on pancreatic cancer cell lines in hypoxia and normoxia. Luciferase reporter assay and Chromatin immunoprecipitation were performed to explore the potential mechanisms in vitro. The combined inhibition of EGFR and Met was evaluated in an orthotopic xenograft mouse model of pancreatic cancer.

FINDINGS

We found that high expression levels of α-SMA and hypoxia markers are associated with poor prognosis of pancreatic cancer patients. Mechanistically, we demonstrated that hypoxia induced the expression and secretion of HGF in PSC via transcription factor HIF-1α. PSC-derived HGF activates Met, the HGF receptor, suppressing the sensitivity of pancreatic cancer cells to EGFR inhibitor in a KRAS-independent manner by activating the PI3K-AKT pathway. Furthermore, we found that the combination of EGFR inhibitor and Met inhibitor significantly suppressed tumor growth in an orthotopic xenograft mouse model.

INTERPRETATION

Our study revealed a previously uncharacterized HIF1α-HGF-Met-PI3K-AKT signaling axis between PSC and cancer cells and indicated that EGFR inhibition plus Met inhibition might be a promising strategy for pancreatic cancer treatment.

FUNDING

This study was supported by The National Natural Science Foundation of China.

Role of hypoxia on microRNA-dependant regulation of HGFA - HGF - c-Met signalling pathway in human progenitor and mature endothelial cells

Hepatocyte growth factor (HGF) is considered to be one of the key pro-angiogenic cytokines that stimulates endothelial cells to proliferate and migrate. The activation of the precursor form of HGF is primarily undertaken by the serine protease HGFA. Research indicates that HIF-1α hypoxia stimulates the expression of HGFA, which is synthesized by a range of cells including fibroblasts, endothelium, and macrophages. To date, little is known about the potential role of epigenetic factors in the regulation of the HGFA - HGF - c-Met signalling pathway. The literature suggests that there are several microRNAs (miRNAs, miRs) directly affecting the expression of c-Met under normoxic conditions. The main objective of the research described was to explore the effect of chemically-induced hypoxia on the expression of miRNA molecules in human progenitor and mature endothelial cells, with particulate attention paid to those miRNAs that may specifically affect the HGFA - HGF - c-Met signalling pathway. This publication sheds new light on the role of miRNAs in hypoxia, as well as identifying several miRNAs directly involved in the regulation of HGFA, HGF and c-Met expression in hypoxic conditions. The results indicate that hsa-miR-335-5p, hsa-miR-425-5p and hsa-miR-101-3p are the major miRNAs that appear to play an important role in the regulation of the HGFA - HGF - c-Met signalling pathway.

A composite of hepatocyte growth factor and 5α-dihydrotestosterone-gelatin microspheres with adipose-derived stem cells enhances wound healing

INTRODUCTION

Reconstructing sebaceous glands is one goal of functionally healing patients who have suffered severe burns, instead of the simple pursuit of wound closure. Effective regeneration of skin appendages remains a challenge in skin wound management and research.

OBJECTIVE

The aim of this study was to evaluate the differentiation of ADSC into sebaceous glands, and clarified the involvement of HGF and 5α-DHT in this process.

METHODS

This study used hepatocyte growth factor (HGF)- and 5α-dihydrotestosterone (5α-DHT)-gelatin microspheres to treat human adipose-derived stem cells (ADSCs) and investigated the reconstruction of sebaceous glands. HGF- and 5α-DHT-gelatin microspheres were constructed using microcapsule slow-release technology. Mice full-thickness skin-wound model was established to evaluate wound healing and hematoxylin-eosin staining was utilized to determine the skin structure.

RESULTS

In vitro analyses found that HGF- and 5α-DHT-gelatin microspheres promoted migration of and tube formation by ADSCs. Furthermore, AKT/ERK signaling, which is related to sebocyte and sweat gland epithelial cell growth, were activated after HGF and 5α-DHT treatment. An in vivo wound healing model demonstrated that ADSCs primed with amnion-loaded HGF- and 5α-DHT-gelatin microspheres promoted wound healing and increased sebaceous gland formation compared to the control group.

CONCLUSIONS

This study confirms the efficacy of ADSCs treated with amnion and HGF- and 5α-DHT-gelatin microspheres in accelerating wound healing and effectively restoring sebaceous glands. This engineered tissue provides insight into and a novel therapeutic material for burns and full-thickness skin wounds.¬¬.

Hepatocyte growth factor regulates HIF-1α-induced nucleus pulposus cell proliferation through MAPK-, PI3K/Akt-, and STAT3-mediated signaling

Intervertebral discs are important for maintaining mobility and offer support to the body trunk. If these discs lose their biomechanical features, lower back pain can occur. We previously reported that hepatocyte growth factor (HGF) promotes cell proliferation and suppresses apoptosis, inflammation, and matrix degradation in nucleus pulposus (NP) cells. In the present study, we investigated the molecular mechanisms of how HGF promotes the proliferation of NP cells in hypoxic conditions. Hypoxic stimulation promoted modest cell proliferation, which was further upregulated by HGF. Expression of hypoxia-inducible factor (HIF-1α) protein, which contributes to the maintenance of homeostasis in NP cells, was also upregulated in hypoxia-treated cell groups; HGF further increased HIF-1α expression in NP cells. Additionally, knockdown of HIF-1α expression significantly reduced the proliferation of NP cells. An MAPK inhibitor inhibited the expression of HIF-1α and pERK, as well as cell proliferation in a dose-dependent manner. Similarly, inhibiting the PI3K/Akt and STAT3 pathways also decreased the expression of HIF-1α and cell proliferation. These results show that under hypoxic conditions, HGF promotes NP cell proliferation via HIF-1α-, MAPK-, PI3K/Akt-, and STAT3-mediated signaling which is involved in this pathway. The control of these signaling pathways may be a target for potential therapeutic strategies for the treatment of disc degeneration in hypoxic conditions.

The PARP Enzyme Family and the Hallmarks of Cancer Part 2: Hallmarks Related to Cancer Host Interactions

Poly (ADP-ribose) polymerases (PARPs) modify target proteins with a single ADP-ribose unit or with a poly (ADP-ribose) (PAR) polymer. PARP inhibitors (PARPis) recently became clinically available for the treatment of BRCA1/2 deficient tumors via the synthetic lethality paradigm. This personalized treatment primarily targets DNA damage-responsive PARPs (PARP1-3). However, the biological roles of PARP family member enzymes are broad; therefore, the effects of PARPis should be viewed in a much wider context, which includes complex effects on all known hallmarks of cancer. In the companion paper (part 1) to this review, we presented the fundamental roles of PARPs in intrinsic cancer cell hallmarks, such as uncontrolled proliferation, evasion of growth suppressors, cell death resistance, genome instability, replicative immortality, and reprogrammed metabolism. In the second part of this review, we present evidence linking PARPs to cancer-associated inflammation, anti-cancer immune response, invasion, and metastasis. A comprehensive overview of the roles of PARPs can facilitate the identification of novel cancer treatment opportunities and barriers limiting the efficacy of PARPi compounds.

Elevated level of microRNA-210 at the initiation of muscular regeneration in acetic acid-induced non-ischemic skeletal muscular injury in mice

The alteration in microRNA-210 level, a hypoxia-inducible microRNA, is not well known in non-ischemic tissue injury. In this study, we characterized the histopathological time course of acetic acid-induced skeletal muscle injury as a non-ischemic tissue injury model and investigated the expression of microRNA-210, hypoxia-inducible factor 1α, and growth factors using quantitative polymerase chain reaction analysis. After a single intramuscular dose of 3% (v/v) acetic acid to C57BL/6J mice, focal coagulative necrosis of muscle fibers was noted from 3 h after dosing and infiltration of F4/80 and Galectin-3 positive M2 macrophage was noted at 1 d after dosing. Muscular regeneration was initiated from 3 d, when M2 macrophage infiltration was most prominent, till 14 d after dosing. Hif1α and Hgf expression increased from 3 h onwards, and microRNA-210 level increased after 3 d after the treatment. However, no clear elevation in the levels of Igf1 or Vegf was observed. The infiltrative macrophages and regenerative muscle fibers were positive for hypoxia-inducible factor 1α, microRNA-210, and hepatocyte growth factor as assessed by immunohistochemistry or in situ hybridization. In this study, dominant infiltration of M2 macrophages at muscular necrosis and subsequent regeneration after a single intramuscular injection of acetic acid in mice were observed. The increase in hif1α level was observed just after the muscular injury in this non-ischemic tissue injury model, and the elevation in microRNA-210 level was noted at the initiation of tissue regeneration, indicating its effects on tissue protection and repair.

The Potential Role of Hepatocyte Growth Factor in Degenerative Disorders of the Synovial Joint and Spine

This paper aims to provide a comprehensive review of the changing role of hepatocyte growth factor (HGF) signaling in the healthy and diseased synovial joint and spine. HGF is a multifunctional growth factor that, like its specific receptor c-Met, is widely expressed in several bone and joint tissues. HGF has profound effects on cell survival and proliferation, matrix metabolism, inflammatory response, and neurotrophic action. HGF plays an important role in normal bone and cartilage turnover. Changes in HGF/c-Met have also been linked to pathophysiological changes in degenerative joint diseases, such as osteoarthritis (OA) and intervertebral disc degeneration (IDD). A therapeutic role of HGF has been proposed in the regeneration of osteoarticular tissues. HGF also influences bone remodeling and peripheral nerve activity. Studies aimed at elucidating the changing role of HGF/c-Met signaling in OA and IDD at different pathophysiological stages, and their specific molecular mechanisms are needed. Such studies will contribute to safe and effective HGF/c-Met signaling-based treatments for OA and IDD.

Regulation of intracellular transition metal ion level with a pH-sensitive inorganic nanocluster to improve therapeutic angiogenesis by enriching conditioned medium retrieved from human adipose derived stem cells

Cell therapy based on human adipose derived stem cells (hADSCs) is a known potential therapeutic approach to induce angiogenesis in ischemic diseases. However, the therapeutic efficacy of direct hADSC injection is limited by a low cell viability and poor cell engraftment after administration. To improve the outcomes of this kind of approach, various types of nanoparticles have been utilized to improve the therapeutic efficacy of hADSC transplantation. Despite their advantages, the adverse effects of nanoparticles, such as genetic damage and potential oncogenesis based on non-degradable property of nanoparticles prohibit the application of nanoparticles toward the clinical applications. Herein, we designed a transition metal based inorganic nanocluster able of pH-selective degradation (ps-TNC), with the aim of enhancing an hADSC based treatment of mouse hindlimb ischemia. Our ps-TNC was designed to undergo degradation at low pH conditions, thus releasing metal ions only after endocytosis, in the endosome. To eliminate the limitations of both conventional hADSC injection and non-degradable property of nanoparticles, we have collected conditioned medium (CM) from the ps-TNC treated hADSCs and administrated it to the ischemic lesions. We found that intracellular increment of transition metal ion upregulated the hypoxia-inducible factor 1α, which can induce vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) expressions. Based on the molecular mechanism, the secretion of VEGF and bFGF by ps-TNC treated hADSCs showed a significant improvement compared to that of untreated cells. Injecting the CM collected from ps-TNC treated hADSCs into the mouse hindlimb ischemia model (ps-TNC-CM group) showed significantly improved angiogenesis in the lesions, with improved limb salvage and decreased muscle degeneration compared to the group injected with CM collected from normal hADSCs (CM group). This study suggests a novel strategy, combining a known angiogenesis molecular mechanism with both an improvement on conventional stem cell therapy and the circumvention of some limitations still present in modern approaches based on nanoparticles.

Protective role of mesenchymal stem cells transfected with miRNA-378a-5p in phosgene inhalation lung injury

Phosgene-induced lung injury is an important type of acute lung injury (ALI). Currently, no effective clinical treatment has been developed yet. Our previous study revealed that expressions of 6 miRNAs were significantly increased in phosgene-induced lung injury. The screened miRNA with the most significant effect on hepatocyte growth factor (HGF) expression by mesenchymal stem cells (MSCs) was transfected into MSCs. This study aimed to investigate whether the transfected MSCs had better therapeutic effects than MSCs alone. MSCs were co-cultured with miRNA mimics for 24h and 48h. HGF expression in culture supernatant was detected by ELISA. HGF expression in MSCs was detected by Western blot after being co-cultured with the selected miRNA inhibitor. The transfected MSCs were given to rats suffering from phosgene-induced lung injury. Expressions of TNF-α, IL-6, IL-1β and IL-10, were assayed by ELISA. SP-C mRNA level was tested by RT-PCR. VE-CAD expression was tested by Western blot. We found that miRNA-378a-5p most increased HGF expression among the six miRNAs. After transfection of MSCs with miRNA-378a-5p inhibitor, HGF expression was decreased. Compared with untreated MSCs, MSCs transfected with miRNA-378a-5p exhibited more significant decreases in lung injury score, white blood cell count and protein content while restoring respiratory indexes. Meanwhile, expressions of TNF-α, IL-6, IL-1β were decreased while those of IL-10, SP-C and VE-cadherin were increased. In conclusion, MSCs transfected with miRNA-378a-5p were more effective in treating phosgene-induced lung injury by repairing the secretion of alveolar epithelial cells and improving the permeability of vascular endothelial cells compared with MSCs alone.

Linc-OIP5 in the breast cancer cells regulates angiogenesis of human umbilical vein endothelial cells through YAP1/Notch/NRP1 signaling circuit at a tumor microenvironment

Background

LincRNAs have been revealed to be tightly associated with various tumorigeneses and cancer development, but the roles of specific lincRNA on tumor-related angiogenesis was hardly studied. Here, we aimed to investigate whether linc-OIP5 in breast cancer cells affects the angiogenesis of HUVECs and whether the linc-OIP5 regulations are involved in angiogenesis-related Notch and Hippo signaling pathways.

Methods

A trans-well system co-cultured HUVECs with linc-OIP5 knockdown breast cancer cell MDA-MB-231 was utilized to study the proliferation, migration and tube formation abilities of HUVECs and alterations of related signaling indicators in breast cancer cells and their conditioned medium through a series of cell and molecular experiments.

Results

Overexpressed linc-OIP5, YAP1, and JAG1 were found in breast cancer cell lines MCF7 and MDA-MB-231 and the expression levels of YAP1 and JAG1 were proportional to the breast cancer tissue grades. MDA-MB-231 cells with linc-OIP5 knockdown led to weakened proliferation, migration, and tube formation capacity of co-cultured HUVECs. Besides, linc-OIP5 knockdown in co-cultured MDA-MB-231 cells showed downregulated YAP1 and JAG1 expression, combined with a reduced JAG1 level in conditioned medium. Furthermore, a disrupted DLL4/Notch/NRP1 signaling in co-cultured HUVECs were also discovered under this condition.

Conclusion

Hence, linc-OIP5 in MDA-MB-231 breast cancer cells may act on the upstream of the YAP1/Notch/NRP1 signaling circuit to affect proliferation, migration, and tube formation of co-cultured HUVECs in a non-cellular direct contact way through JAG1 in conditioned medium. These findings at least partially provide a new angiogenic signaling circuit in breast cancers and suggest linc-OIP5 could be considered as a therapeutic target in angiogenesis of breast cancers.

Retinal blood oxygen saturation and aqueous humour biomarkers in early diabetic retinopathy

PURPOSE

The aim of this study was to assess the relationship between retinal blood oxygen saturation (SO₂ ) and specific aqueous humour (AH) concentrations of proangiogenic biomarkers in diabetic patients with nonproliferative diabetic retinopathy (NPDR) and to compare them with those of matched control subjects.

METHODS

The sample comprised 14 participants with mild-to-moderate NPDR (69.1 ± 6.6 years) and 17 age-matched healthy controls (69.7 ± 6.3 years); all participants were previously scheduled for routine cataract extraction with intraocular lens implantation. Multiplex cytokine analyses of specific biomarkers, including vascular endothelial growth factor A (VEGF-A), angiopoietin2 (Ang2), epidermal growth factor (EGF), hepatocyte growth factor (HGF) and interleukin-8 (IL-8) were performed by BioPlex 200 system. Six non-invasive hyperspectral retinal images were acquired.

RESULTS

Mean SO₂ was significantly higher in both arterioles (94.4 ± 1.9 versus 93.0 ± 1.6) and venules (64.4 ± 5.6 versus 55.9 ± 4.8) of NPDR than in the healthy controls (p < 0.001). AH levels of HGF (p = 0.018), Ang2 (p = 0.005) and IL-8 (p = 0.034) were significantly higher, and EGF (p = 0.030) was significantly lower in NPDR subjects. The study demonstrated a correlation between venular retinal blood oxygen saturation and proangiogenic factors HGF (r = 0.558, p = 0.038), Ang2 (r = 0.556, p = 0.039) and EGF (r = -0.554, p = 0.040), but did not find any correlation for IL-8 (r = 0.330, p = 0.249) even though this biomarker was significantly higher in the diabetic group.

CONCLUSION

To our knowledge, the present study is the first report considering the association between SO₂ and AH concentrations of protein biomarkers in diabetic retinopathy. The biomarkers of interest have been shown to participate in cell death, which may explain higher oxygen saturation in NPDR.

Transplantation of Endothelial Progenitor Cells Overexpressing miR-126-3p Improves Heart Function in Ischemic Cardiomyopathy

BACKGROUND

In a previous study, a low level of miR-126-3p in endothelial progenitor cells (EPCs) was linked to the outcome of ischemic cardiomyopathy (ICM) patients. However, it remains unclear whether transplantation with miR-126-3p-overexpressing EPCs (MO-EPCs) can improve the cardiac function of ICM animal models. Methods and Results: miR-126-3p overexpression by lentiviral vector significantly increased migration and tube-like structures of EPCs from ICM patients. MO-EPCs or non-modified EPCs (NM-EPCs) were transplanted into nude rats with ICM induced by coronary artery ligation. MO-EPC transplantation increased capillary density and EPC survival rate in myocardial tissues of nude rats. Cytokines were also assessed by antibody array and real-time RT-PCR. G-CSF, VEGF-A, IL-3, IL-10, IGF-1, angiogenin, HGF, TIMP-1 and TIMP-2 were upregulated, and IL-8, MCP-1, MCP-2, TNF-α, TNF-β and MIP-1β were downregulated after miR-126-3p overexpression in EPCs. The same results were obtained in infarction tissues of nude rats after MO-EPC transplantation. Eight weeks after MO-EPC transplantation, left ventricular function improved significantly with clearly decreased infarction size, increased anterior wall thickness, and inhibition of inflammation compared with the results for NM-EPC transplantation. However, MO-EPC transplantation showed no increase in survival time of nude rats with ICM during 8 weeks of observation.

CONCLUSIONS

miR-126-3p can restore the biology of EPCs from ICM patients. Moreover, MO-EPC transplantation improves cardiac function effectively, representing a promising future treatment for ICM.

Targeting hypoxic response for cancer therapy

Hypoxic tumor microenvironment (HTM) is considered to promote metabolic changes, oncogene activation and epithelial mesenchymal transition, and resistance to chemo- and radio-therapy, all of which are hallmarks of aggressive tumor behavior. Cancer cells within the HTM acquire phenotypic properties that allow them to overcome the lack of energy and nutrients supply within this niche. These phenotypic properties include activation of genes regulating glycolysis, glucose transport, acidosis regulators, angiogenesis, all of which are orchestrated through the activation of the transcription factor, HIF1A, which is an independent marker of poor prognosis. Moreover, during the adaptation to a HTM cancer cells undergo deep changes in mitochondrial functions such as “Warburg effect” and the “reverse Warburg effect”.

This review aims to provide an overview of the characteristics of the HTM, with particular focus on novel therapeutic strategies currently in clinical trials, targeting the adaptive response to hypoxia of cancer cells.

Endothelial progenitor cells for cellular angiogenesis and repair: lessons learned from experimental animal models

Stem/progenitor cell-based therapy has been extensively studied for angiomyogenic repair of the ischemic heart by regeneration of the damaged myocytes and neovascularization of the ischemic tissue through biological bypassing. Given their inherent ability to assume functionally competent endothelial phenotype and release of broad array of proangiogenic cytokines, endothelial progenitor cells (EPCs)-based therapy is deemed as most appropriate for vaculogenesis in the ischemic heart. Emulating the natural repair process that encompasses mobilization and homing-in of the bone marrow and peripheral blood EPCs, their reparability has been extensively studied in the animal models of myocardial ischemia with encouraging results. Our literature review is a compilation of the lessons learned from the use of EPCs in experimental animal models with emphasis on the in vitro manipulation and delivery strategies to enhance their retention, survival and functioning post-engraftment in the heart.

Involvement of endothelial progenitor cells in the formation of plexiform lesions in broiler chickens: possible role of local immune/inflammatory response

Plexiform lesions (PLs), which are often accompanied by perivascular infiltrates of mononuclear cells, represent the hallmark lesions of pulmonary arteries in humans suffering from severe pulmonary arterial hypertension (PAH). Endothelial progenitor cells (EPCs) have been recently implicated in the formation of PLs in human patients. PLs rarely develop in rodent animal models of PAH but can develop spontaneously in broiler chickens. The aim of the present study was to confirm the presence of EPCs in the PLs in broilers. The immune mechanisms involved in EPC dysfunction were also evaluated. Lungs were collected from commercial broilers at 1 to 4 weeks of age. The right/total ventricle ratios indicated normal pulmonary arterial pressures for all sampled birds. Immunohistochemistry was performed to determine the expressions of EPC markers (CD133 and VEGFR-2) and proangiogenic molecule hepatocyte growth factor (HGF) in the lung samples. An EPC/lymphocyte co-culture system was used to investigate the functional changes of EPCs under the challenge of immune cells. PLs with different cellular composition were detected in the lungs of broilers regardless of age, and they were commonly surrounded by moderate to dense perivascular mononuclear cell infiltrates. Immunohistochemical analyses revealed the presence of CD133⁺ and VEGFR-2⁺ cells in PLs. These structures also exhibited a strong expression of HGF. Lymphocyte co-culture enhanced EPC apoptosis and completely blocked HGF-stimulated EPC survival and in vitro tube formation. Taken together, this work provides evidence for the involvement of EPCs in the development of PLs in broilers. It is suggested that the local immune cell infiltrate might serve as a contributor to EPC dysfunction by inducing EPC death and limiting their response to angiogenic stimuli. Broiler chickens may be valuable for investigating reversibility of plexogenic arteriopathy using gene-modified inflammation-resistant EPCs.

Hypoxia inducible factor down-regulation, cancer and cancer stem cells (CSCs): ongoing success stories

In cancers, hypoxia inducible factor 1 (HIF-1) is an over-expressed transcription factor, which regulates a large set of genes involved in tumour vascularization, metastases, and cancer stem cells (CSCs) formation and self-renewal. This protein has been identified as a relevant target in oncology and several HIF-1 modulators are now marketed or in advanced clinical trials. The purpose of this review is to summarize the advances in the understanding of its regulation and its inhibition, from the medicinal chemist point of view. To this end, we selected in the recent literature relevant examples of "hit" compounds, including small-sized organic molecules, pseudopeptides and nano-drugs, exhibiting in vitro and/or in vivo both anti-HIF-1 and anti-tumour activities. Whenever possible, a particular emphasis has been dedicated to compounds that selectively target CSCs.

Hypoxia-Driven Mechanism of Vemurafenib Resistance in Melanoma

Melanoma is molecularly and structurally heterogeneous, with some tumor cells existing under hypoxic conditions. Our cell growth assays showed that under controlled hypoxic conditions, BRAF(V600E) melanoma cells rapidly became resistant to vemurafenib. By employing both a three-dimensional (3D) spheroid model and a two-dimensional (2D) hypoxic culture system to model hypoxia in vivo, we identified upregulation of HGF/MET signaling as a major mechanism associated with vemurafenib resistance as compared with 2D standard tissue culture in ambient air. We further confirmed that the upregulation of HGF/MET signaling was evident in drug-resistant melanoma patient tissues and mouse xenografts. Pharmacologic inhibition of the c-Met/Akt pathway restored the sensitivity of melanoma spheroids or 2D hypoxic cultures to vemurafenib. Mol Cancer Ther; 15(10); 2442-54. ©2016 AACR.

The hepatocyte growth factor-expressing character is required for mesenchymal stem cells to protect the lung injured by lipopolysaccharide in vivo

BACKGROUND

Acute respiratory distress syndrome (ARDS) is a life-threatening condition in critically ill patients. Recently, we have found that mesenchymal stem cells (MSC) improved the permeability of human lung microvascular endothelial cells by secreting hepatocyte growth factor (HGF) in vitro. However, the properties and functions of MSC may change under complex circumstances in vivo. Here, we sought to determine the role of the HGF-expressing character of MSC in the therapeutic effects of MSC on ARDS in vivo.

METHODS

MSC with HGF gene knockdown (MSC-ShHGF) were constructed using lentiviral transduction. The HGF mRNA and protein levels in MSC-ShHGF were detected using quantitative real-time polymerase chain reaction and Western blotting analysis, respectively. HGF levels in the MSC culture medium were measured by enzyme-linked immunosorbent assay (ELISA). Rats with ARDS induced by lipopolysaccharide received MSC infusion via the tail vein. After 1, 6, and 24 h, rats were sacrificed. MSC retention in the lung was assessed by immunohistochemical assay. The lung wet weight to body weight ratio (LWW/BW) and Evans blue dye extravasation were obtained to reflect lung permeability. The VE-cadherin was detected with inmmunofluorescence, and the lung endothelial cell apoptosis was assessed by TUNEL assay. The severity of lung injury was evaluated using histopathology. The cytokines and HGF levels in the lung were measured by ELISA.

RESULTS

MSC-ShHGF with markedly lower HGF expression were successfully constructed. Treatment with MSC or MSC carrying green fluorescent protein (MSC-GFP) maintained HGF expression at relatively high levels in the lung at 24 h. MSC or MSC-GFP decreased the LWW/BW and the Evans Blue Dye extravasation, protected adherens junction VE-cadherin, and reduced the lung endothelial cell apoptosis. Furthermore, MSC or MSC-GFP reduced the inflammation and alleviated lung injury based on histopathology. However, HGF gene knockdown significantly decreased the HGF levels without any changes in the MSC retention in the lung, and diminished the protective effects of MSC on the injured lung, indicating the therapeutic effects of MSC on ARDS were partly associated with the HGF-expressing character of MSC.

CONCLUSIONS

MSC restores lung permeability and lung injury in part by maintaining HGF levels in the lung and the HGF-expressing character is required for MSC to protect the injured lung.