Transjugular Transcatheter Tricuspid Valve Implantation of LuX-Valve Bioprosthesis in a Preclinical Model.

The purpose of this preclinical study in a sheep model was to confirm the feasibility and safety of the LuX-Valve transjugular tricuspid valve (TV) replacement apparatus and to optimize the implantation procedure before beginning first-in-man study. The LuX-Valve was implanted in a sheep model (n = 8) via transjugular approach. Six of eight sheep underwent successful implantation procedure on beating heart. The first two sheep died during the prostheses deployment. In the remaining 6 sheep that survived, postoperative echocardiography results showed there was no paravalvular leakage (PVL) and central tricuspid regurgitation in 5 animals, whereas 1 animal had mild PVL. The mean transvalvular gradient was 1.1 ± 0.9 mm Hg at the 4-week follow-up. No right ventricular outflow tract (RVOT) obstruction, device malposition, pericardial effusion, coronary artery compression, or arrhythmias were observed. This technology may be a promising alternative for TR patients who are at high risk for open-heart surgery. Transjugular tricuspid valved-stent implantation. a Transjugular tricuspid valve replacement in a sheep model. b and c Valved stent. d, e, and f Schematic depiction of the implantation procedure.

Twist-related protein 1 negatively regulated osteoblastic transdifferentiation of human aortic valve interstitial cells by directly inhibiting runt-related transcription factor 2.

OBJECTIVE: Valve calcification involves transdifferentiation of valve interstitial cells (VICs) into osteoblasts. Twist-related protein 1 (TWIST1) has been established as a negative regulator of osteoblast differentiation in both mouse and human mesenchymal stem cells, but its function in human aortic VICs is unknown. In our study, we determined the mechanism of TWIST1 action in regulating osteoblastic transdifferentiation of human aortic VICs. METHODS: Human calcified and noncalcified aortic valves were examined for TWIST1 expression. Human aortic VICs were isolated and cultured. RESULTS: The data showed that calcified aortic valves express lower levels of TWIST1. In vitro experiments showed that TWIST1 overexpression inhibited the transdifferentiation of VICs into osteoblasts by decreasing the expression of runt-related transcription factor 2 (RUNX2) and its downstream osteoblastic markers. Through chromatin immunoprecipitation and dual luciferase assays, we found that TWIST1 repressed the expression of RUNX2 by directly binding to an E-box located at -820 bp of the RUNX2 P2 promoter region and inhibiting its activity. CONCLUSIONS: Our study results suggest that TWIST1 could play an important role in preventing human aortic valve calcification by negatively regulating osteoblastic transdifferentiation of human aortic VICs through direct inhibition of RUNX2.

Tumor cells positive and negative for the common cancer stem cell markers are capable of initiating tumor growth and generating both progenies.

The cancer stem cell (CSC) model depicts that tumors are hierarchically organized and maintained by CSCs lying at the apex. CSCs have been "identified" in a variety of tumors through the tumor-forming assay, in which tumor cells distinguished by a certain cell surface marker (known as a CSC marker) were separately transplanted into immunodeficient mice. In such assays, tumor cells positive but not negative for the CSC marker (hereby defined as CSC(+) and CSC(-) cells, respectively) have the ability of tumor-forming and generating both progenies. However, here we show that CSC(+) and CSC(-) cells exhibit similar proliferation in the native states. Using a cell tracing method, we demonstrate that CSC(-) cells exhibit similar tumorigenesis and proliferation as CSC(+) cells when they were co-transplanted into immunodeficient mice. Through serial single-cell derived subline construction, we further demonstrated that CSC(+) and CSC(-) cells from CSC marker expressing tumors could invariably generate both progenies, and their characteristics are maintained among different generations irrespective of the origins (CSC(+)-derived or CSC(-)-derived). These findings demonstrate that tumorigenic cells cannot be distinguished by common CSC markers alone and we propose that cautions should be taken when using these markers independently to identify cancer stem cells due to the phenotypic plasticity of tumor cells.

MicroRNA-98 and microRNA-214 post-transcriptionally regulate enhancer of zeste homolog 2 and inhibit migration and invasion in human esophageal squamous cell carcinoma.

BACKGROUND: The enhancer of zeste homolog 2 (EZH2) was found to be overexpressed and associated with tumor metastasis in esophageal squamous cell carcinoma (ESCC). On the other hand, it was reported that miR-26a, miR-98, miR-101, miR-124, miR-138 and miR-214 could inhibit the expression of EZH2 in some tumors. However, the role of miRNAs in the regulation of EZH2 expression in human ESCC has not been documented. The aim of this study was to determine the role of these miRNAs in the regulation of tumor metastasis via EZH2 overexpression in human ESCC. METHODS AND RESULTS: The expression of these miRNAs and EZH2 mRNA were examined by qPCR and the expression of EZH2 protein was detected by western blot. The role of these miRNAs in migration and invasion was studied in ESCC cell line (Eca109) transfected with miRNA mimics or cotransfected with miRNA mimics and pcDNA-EZH2 plasmid (without the 3'-UTR of EZH2). Through clinical investigation, we found that miR-98 and miR-214 expression was significantly lower in ESCC tissues than in matched normal tissues, and the expression level of miR-98 and miR-214 was inversely correlated to EZH2 protein expression and the clinical features such as pathological grade, tumor stage and lymph node metastasis in ESCC. In Eca109 cells, overexpression of miR-98 and miR-214 significantly inhibited the migration and invasion of ESCC cells, which was reversed by transfection of EZH2. CONCLUSIONS: These findings suggest that decreased expression of miR-98 and miR-214 might promote metastasis of human ESCC by inducing accumulation of EZH2 protein.

PRAF3 induces apoptosis and inhibits migration and invasion in human esophageal squamous cell carcinoma.

BACKGROUND: Prenylated Rab acceptor 1 domain family member 3 (PRAF3) is involved in the regulation of many cellular processes including apoptosis, migration and invasion. This study was conducted to investigate the effect of PRAF3 on apoptosis, migration and invasion in human esophageal squamous cell carcinoma (ESCC). METHODS: The expression of PRAF3 mRNA and protein in primary ESCC and the matched normal tissues (57cases) was determined by quantitative RT-PCR and Western blot. Immunohistochemical analysis of PRAF3 expression was carried out in paraffin-embedded sections of ESCC and correlated with clinical features. The role of PRAF3 in apoptosis, migration and invasion was studied in ESCC cell lines of Eca109 and TE-1 through the adenovirus mediated PRAF3 gene transfer. The effect of PRAF3 on apoptosis was analyzed by annexin V-FITC assay. The regulation of PRAF3 on migration was determined by transwell and wounding healing assay, while the cellular invasion was analyzed by matrigel-coated transwell assay. RESULTS: We found that the expression of PRAF3 was significantly down-regulated in ESCC tissue compared with the matched normal tissue and was correlated with the clinical features of pathological grade, tumor stage and lymph node metastasis. Moreover, overexpression of PRAF3 induced cell apoptosis through both caspase-8 and caspase-9 dependent pathways, and inhibited cell migration and invasion by suppressing the activity of both MMP-2 and MMP-9 in human ESCC cell lines. CONCLUSIONS: Our data suggest that PRAF3 plays an important role in the regulation of tumor progression and metastasis and serves as a tumor suppressor in human ESCC. We propose that PRAF3 might be used as a potential therapeutic agent for human ESCC.

MicroRNA-203 inhibits cell proliferation by repressing ΔNp63 expression in human esophageal squamous cell carcinoma.

BACKGROUND: This study was performed to investigate the effect of microRNA-203 (miR-203) and ΔNp63 on cell proliferation and the functional connection between miR-203 and ΔNp63 in ESCC. METHODS: We employed 2 human ESCC cell lines, Eca109 and TE-1, as the model system. The effect of miR-203 and ΔNp63 on cell proliferation was determined in cells transfected with miR-203 mimic and ΔNp63 small interfering RNA (siRNA), respectively. The regulation of ΔNp63 expression in ESCC cells by miR-203 was studied by luciferase reporter assay, RT-PCR and western blot analysis in cells transfected with miR-203. The effect of ΔNp63 re-expression on miR-203 induced inhibition of cell proliferation was studied by cell proliferation assay in cells cotransfected with miR-203 and pcDNA-ΔNp63 plasmid (without the 3'-UTR of ΔNp63). RESULTS: We found that both miR-203 and ΔNp63 siRNA signicantly inhibited cell proliferation in ESCC. MiR-203 could down-regulate endogenous ΔNp63 expression at the posttranscriptional level. Moreover, re-expression of ΔNp63 in cells transfected with miR-203 significantly attenuated the miR-203 induced inhibition of cell proliferation. CONCLUSIONS: Our data implied that miR-203 could inhibit cell proliferation in human ESCC through ΔNp63-mediated signal pathway. Therefore, we propose that miR-203 might be used as a therapeutic agent for human ESCC.

Intrathecal siRNA against Toll-like receptor 4 reduces nociception in a rat model of neuropathic pain.

BACKGROUND: Neuropathic pain is characterized by hyperalgesia, allodynia and spontaneous pain. It often occurs as a result of injury to peripheral nerves, dorsal root ganglions (DRG), spinal cord, or brain. Recent studies have suggested that Toll-like receptor 4 (TLR4) might play a role in neuropathic pain. METHODOLOGY/PRINCIPAL FINDINGS: In this study, we investigated the role of TLR4 in a rat chronic constriction injury (CCI) model and explored the feasibility of treating neuropathic pain by inhibiting TLR4. Our results demonstrated that intrathecal siRNA-mediated suppression of TLR4 attenuated CCI-induced mechanical allodynia and thermal hyperalgesia through inhibiting the activation of NF-kappaB p65 and production of proinflammatory cytokines (e.g., TNF-alpha and IL-1 beta). CONCLUSIONS/SIGNIFICANCE: These findings suggest that suppression of TLR4 mediated by intrathecally administered siRNA may be a new strategy for the treatment of neuropathic pain.

[Isolation and identification of cancer stem cells from human esophageal carcinoma].

OBJECTIVE: To isolate and identify cancer stem cells from esophageal carcinoma cells (ECCs) using cell surface marker p75NTR. METHODS: ECCs cell lines were established with ECCs collected from 38 surgically resected specimens. Flow cytometry was used to identify the p75NTR positive cells therein that were isolated then using magnetic activated cell sorting (MACS) method. The growing characteristics in DMEM medium and capability of colony-forming in soft agar of the p75NTR positive cells were evaluated ex vivo with MTT method. p75NTR positive cells of different concentrations were subcutaneously injected into the backs of Balb/c nude mice and PBS was injected into the contralateral back, and then tumorigenesis was observed, 8 weeks later the mice were killed with their tumors taken out to undergo microscopy. RESULTS: Eight ECCs cell lines were established, 6 of which were found to contain 0.32%-3.35% of p75NTR positive cells. The purity of p75NTR positive cells isolated by MACS was up to 90%. MTT result showed that population doubling time of the p75NTR positive cells was (17+/-3) hours, significantly shorter than that of the p75NTR negative cells [(37+/-7) hours, P<0.01]. The colony-forming rate in soft agar of the p75NTR positive cells was (45.9%+/-8.9%), significantly higher than that of the p75NTR negative cells [(3.7%+/-2.1%), P<0.01]. As few as 2000 p75NTR positive cells gave rise to new tumors in xenotransplantation, with a tumorigenic ability 50 times as high as that of the p75NTR negative cells. CONCLUSION: p75NTR positive cells carry some properties of cancer stem cells, such as the ability of self-renewal, differentiation and proliferation and demonstrate higher ability of colony-forming ex vivo and tumorigenesis in vivo.

[Recombinant adeno-associated virus mediated RNA interference of angiogenin expression inhibits cell growth of human lung adenocarcinoma].

OBJECTIVE: To study the inhibition of angiogenin (ANG) expression in human lung squamous cancer cell strain-A549 through adeno-associated virus (AAV)-mediated RNA-interference, and therefore to observe its effect on the growth of cancer cells and tumor formation. METHODS: Recombinant AAV expressing H1-promoter-induced small-interference- RNA (siRNA) targeting ANG (AAV-shANG) was constructed, and then transfected into A549 cells. A549 cells and cells transfected with AAV-Null were used as the control groups. The effects of the reduced expression of ANG by RNAi from AAV-shANG on the growth, formation, reproduction, apoptosis, and microvessel-density of the carcinoma were observed. RESULTS: In vitro experiment showed that AAV-shANG was constructed successfully, There was an significant decrease in the expression of ANG protein 72 h after transfection, compared with the normal A459 cells and AAV-Null cells (P < 0.01). Cell cycle analysis showed that the proliferation index (PI) of normal A549 cells, AAV-Null cells and AAVshANG cells were 0.32 +/- 0.29, 0.35 +/- 0.38 and 0.31 +/- 0.43, respectively. There was no statistic difference in the PIs among the 3 groups (P > 0.05). In vivo experiment using thymus-defect mice showed that, there was an remarkable reduction in the mass and volume of tumors in AAV-shANG transfected group, compared to the control groups. Microvessel-density was 9.4 +/- 1.5, 9.8 +/- 2.1 and 5.7 +/- 1.9, respectively in the 3 groups, a statistic difference among the AAV-shANG-transfected group, the normal A549 group and the AAV-Null transfected group. The percentages of apoptotic cells in each group were (7.7 +/- 3.1)%, (8.5 +/- 5.4)%, (17.1 +/- 8.6)%, respectively, the experimental group being higher than those of the control groups. Positive rates of PCNA were (84.8 +/- 9.7)%, (85.8 +/- 9.8)%, and (70.4 +/- 10.1)%, respectively, the AAV-shANG transfected cancer cells showing a lower PCNA index than the control groups. CONCLUSION: AAV-mediated expression of siRNA could reduce the expression of ANG in cancer cells, significantly enough to inhibit cell proliferation, promote cell apoptosis and inhibit tumor growth.

Angiogenin is involved in lung adenocarcinoma cell proliferation and angiogenesis.

Angiogenin, a basic heparin-binding protein, has been shown to play a key role in tumor growth and angiogenesis. It was found in the present study that 67 out of 100 lung adenocarcinomas exhibited angiogenin nuclear expression, and this nuclear expression correlated with vascular and pleural invasion as well as positive lymph node metastasis. To down-regulate angiogenin expression, we constructed an adenoviral-vector based short hairpin RNA system. ELISA, real-time qPCR and immunocytochemical staining demonstrated that adenoviral-vector based siRNA decreased angiogenin mRNA level and protein secretion, and inhibited angiogenin nuclear expression in A549 cells, resulting in marked inhibition on ribosomal RNA transcription, in vitro cell proliferation, soft agar colony formation, and xenograft tumor proliferation and angiogenesis. Experiments with neomycin further confirmed that angiogenin nuclear expression played an important role in tumor growth. Based on these data, we concluded that angiogenin nuclear expression played a dual role in the growth of lung adenocarcinoma with respect to cancer cell proliferation and angiogenesis.

Self-renewal and chemotherapy resistance of p75NTR positive cells in esophageal squamous cell carcinomas.

BACKGROUND: p75NTR has been used to isolate esophageal and corneal epithelial stem cells. In the present study, we investigated the expression of p75NTR in esophageal squamous cell carcinoma (ESCC) and explored the biological properties of p75NTR+ cells. METHODS: p75NTR expression in ESCC was assessed by immunohistochemistry. p75NTR+ and p75NTR- cells of 4 ESCC cell lines were separated by fluorescence-activated cell sorting. Differentially expressed genes between p75NTR+ and p75NTR- cells were determined by real-time quantitative reverse transcription-PCR. Sphere formation assay, DDP sensitivity assay, 64copper accumulation assay and tumorigenicity analysis were performed to determine the capacity of self-renewal, chemotherapy resistance and tumorigenicity of p75NTR+ cells. RESULTS: In ESCC specimens, p75NTR was found mainly confined to immature cells and absent in cells undergoing terminal differentiation. The percentage of p75NTR+ cells was 1.6%-3.7% in Eca109 and 3 newly established ESCC cell lines. The expression of Bmi-1, which is associated with self-renewal of stem cells, was significantly higher in p75NTR+ cells. p63, a marker identified in keratinocyte stem cells, was confined mainly to p75NTR+ cells. The expression of CTR1, which is associated with cisplatin (DDP)-resistance, was significantly decreased in p75NTR+ cells. Expression levels of differentiation markers, such as involucrin, cytokeratin 13, beta1-integrin and beta4-integrin, were lower in p75NTR+ cells. In addition, p75NTR+ cells generated both p75NTR+ and p75NTR- cells, and formed nonadherent spherical clusters in serum-free medium supplemented with growth factors. Furthermore, p75NTR+ cells were found to be more resistant to DDP and exhibited lower 64copper accumulation than p75NTR- cells. CONCLUSION: Our results demonstrated that p75NTR+ cells possess some characteristics of CSCs, namely, self-renewal and chemotherapy resistance. Chemotherapy resistance of p75NTR+ cells may probably be attributable to decreased expression of CTR1.

Therapeutic potential of angiogenin modified mesenchymal stem cells: angiogenin improves mesenchymal stem cells survival under hypoxia and enhances vasculogenesis in myocardial infarction.

BACKGROUND: To examine the effects of angiogenin modified mesenchymal stem cells (MSCs) on ventricular remodeling and cardiac function in a rat model of acute myocardial infarction. METHODS: MSCs were transfected with adenoviral vectors carrying either angiogenin (MSC(AdANG)) or EGFP (MSC(AdEGFP)). Angiogenin gene amplification, protein expression and cell death were assayed after hypoxic treatment. DiI labeled MSC(AdANG) and MSC(AdEGFP) were injected into infracted heart. Six weeks after cell transplantation, echocardiography and histological study were performed. RESULTS: After hypoxia treatment, angiogenin modified MSCs effectively expressed angiogenin for at least 14 days. The death of MSC(AdANG) was one-third of MSCAd(EGFP), and 50% of untreated MSCs. In the infracted myocardium, the number of DiI labeling cells in MSC(AdANG) group with high angiogenin expression was three-fold that in MSC(AdEGFP) group. Echocardiograms suggested that angiogenin modified MSCs significantly improved left ventricular (LV) systolic and diastolic function. Histological study confirmed that ventricular remodeling was attenuated significantly in MSC(AdANG) group. Furthermore, vasculogenesis was enhanced significantly in MSC(AdANG) group as measured by both factor VIII and alpha-SMA staining. CONCLUSION: Angiogenin modified MSCs enhanced the tolerance of engrafted MSCs to hypoxia injury in vitro and improved their viability in infracted hearts, thus helping preserve the LV contractile function and attenuate LV remodeling through vasculogenesis.

Angiopoietin-1 targeted RNA interference suppresses angiogenesis and tumor growth of esophageal cancer.

AIM: To determine the inhibitory effect of the adenovirus-based angiopoietin-1 (Ang-1) targeted small interfering RNA expression system (Ad/Ang-1si) on the expression of the Ang-1 gene, cell growth and apoptosis in human esophageal cancer cell line Eca109. METHODS: siRNA-expressing adenovirus targeting Ang-1 gene was constructed using the Ad Easy System. Cultured Eca109 cells were transfected with Ad/Ang-1si (Eca109/Ang-1si), and Ad/si was used to infect Eca109 cells as control (Eca109/si). Ang-1 gene expression and concentration was determined with RT-PCR and ELISA, respectively. Human umbilical vein endothelial cell (HUVEC) migration and proliferation were analyzed. After s.c. injection into athymic nu/nu mice, the tumor growth, vessel density and apoptosis of each group was also determined. RESULTS: HUVEC migration induced by conditioned medium from Ang-1si-transfected Eca109 cells was significantly less than that induced by conditioned medium from Eca109 cells and control adenovirus-transfected Eca109 cells. Furthermore, after s.c. injection into athymic nu/nu mice, the tumor growth and cell apoptosis of Ad/Ang-1si -expressing Eca109 cells was significantly lower than that of parental or control adenovirus-transfected cells. Vessel density assessed by CD31 immunohistochemical analysis and Ang-1 expression by RT-PCR were also decreased. CONCLUSION: The targeting Ang-1 may provide a therapeutic option for esophageal cancer.

Synergistic effect of fibronectin and hepatocyte growth factor on stable cell-matrix adhesion, re-endothelialization, and reconstitution in developing tissue-engineered heart valves.

Stable cell-matrix adhesion, re-endothelialization, and reconstitution represent important issues in creating autologous living heart valve, a close collaboration between growth factors and the extracellular matrix in these processes appears crucial. To prove this action, porcine decellularized valve constructs were precoated with fibronectin and seeded with hepatocyte growth factor-transferred marrow stromal cells (MSCs) and grown in vitro in a pulsatile-flow bioreactor. Results showed hepatocyte growth factor stimulated adhesion of MSCs to fibronectin in a time-dependent manner with a range of 8-128 ng/ml. Histological observation demonstrated a time course of MSC growth on decellularized valve constructs. A handful of cells, a loose cellular layer, a confluent monolayer coverage, a 2-layer structure and a 3-layer structure were observed at weeks 2, 3, 4, 6, and 8, respectively. Immunohistochemical analysis revealed cellular reconstitution of endothelial cells (von Willebrand factor positive) and myofibroblasts (alpha-smooth muscle actin and vimentin double-positive) at week 8. Importantly, endothelial cell retention (17.3 +/- 2.6/mm) remained high under exposure to high flow and pressure conditions in a bioreactor. These results demonstrated that the combination of fibronectin and hepatocyte growth factor contributed to creating autologous living heart valve.

Transplantation of angiogenin-overexpressing mesenchymal stem cells synergistically augments cardiac function in a porcine model of chronic ischemia.

OBJECTIVE: Accumulated evidence suggests that myogenesis and angiogenesis induced by implanted cells play important roles in restoring cardiac function after a myocardial infarction. The current study investigated the effects of transplanted autologous mesenchymal stem cells overexpressing angiogenin on myocardial perfusion and cardiac function in the porcine chronic ischemic model. METHODS: Chronic ischemia was generated in Yorkshire pigs by placing an ameroid constrictor around the left circumflex artery. Four weeks after occlusion, the animals were randomly separated into 4 groups: pigs in the MSC(AdAng) or MSC(AdNull) groups were implanted with 6 x 10(8) mesenchymal stem cells infected with adenovirus containing angiogenin gene or null adenovirus, respectively; pigs in the AdAng or AdNull groups were injected intramyocardially with adenovirus (5 x 10(9) plaque forming unit/pig) containing angiogenin gene or null adenovirus, respectively. Four weeks after implantation, mesenchymal stem cells prelabeled with DiI were observed within the implanted area in both cell transplantation groups. RESULTS: Angiogenin protein levels were significantly greater in the MSC(AdAng) and AdAng groups than in the other 2 groups and were associated with greater neovessel formation than in the other 2 groups. Mesenchymal stem cell transplantation decreased scar size and increased scar thickness. Both the AdAng and MSC(AdNull) groups experienced improved cardiac function compared with that seen in the AdNull group. However, a synergistic effect of mesenchymal stem cells and angiogenin was observed in the MSC(AdAng) group because myocardial perfusion and cardiac function increased significantly (P < .05 for all groups) in this group compared with all the others. CONCLUSIONS: Transplantation of autologous mesenchymal stem cells transfected with the angiogenin gene revealed a synergistic effect on the improvement of heart perfusion and function after ameroid occlusion.