In this study we describe and discuss the dichotomous effects of docetaxel trastuzumab (Herceptin)/docetaxel therapy on the angiogenic molecular profile in two patients with her-2 + chemo-resistant recurrent breast carcinoma. In the first case, an intensification of angiogenesis occurred following therapy, accompanied by an impressive increase of the cancer cell proliferation index. This tumor did not express HIF1 alpha and shared a HIF-independent VEGF overexpression, which remained unaffected by therapy. An intensified formation of thymidine phosphorylase (TP)-rich stroma, presumably a response to docetaxel, shows a TP-dependent angiogenic response. In the second patient, VEGF and HIF1 alpha were down-regulated in post-treatment biopsies and this was accompanied by a sharp reduction of the vascular density and of the cancer cell proliferation rate. In both cases, c-erbB-2 expression was abrogated by Herceptin. Taking into account that Herceptin down-regulates VEGF through reduction of HIF1 alpha synthesis, this clinical study provides evidence that an anti-angiogenic effect from Herceptin/Docetaxel therapy is expected only in tumors with HIF1 alpha-dependent VEGF overexpression. In contrast, HIF1 alpha-independent VEGF angiogenic activity cannot be abrogated by Herceptin. Docetaxel mediated up-regulation of TP in the tumoral stroma may, on the contrary, result in angiogenesis intersification and rapid tumor relapse. Such an effect should be of clinical importance since Herceptin/Docetaxel-based regimens are currently evaluated for the adjuvant therapy of her-2 + breast cancer patients. Studying the Herceptin-induced phenotypic changes of tumors could lead to the identification of specific molecular profiles that bring about diverging angiogenic responses. Adjustment of the chemotherapy regimen accordingly would prove of clinical importance.

Dichlorvos (DDVP) is an organophosphate compound that causes neurotoxicity. Apoptosis plays an important role in neurotoxic cell death in the brain. The aim of this study was to examine caspase 1, caspase-3 and also cell apoptosis related genes as p53, Tumor Necrosis Factor-alpha, Hypoxia Inducible Factor 1-alpha expressions in hippocampus, cerebellum, cortex, and to estimate total hippocampal neuron number in DDVP treated rats. Ten female albino rats were divided into control (n:5) and dose (n:5) groups. In dose group, single dose of DDVP (25 mg/kg) was administered to the animals via oral gavage. A week later, brains were removed and total neuron number was estimated in the left hippocampus using by optical fractionator method. The right part of the brain was used for gene expression analysis. In dose group, total hippocampal neuron number was significantly decreased compared to control group (p = 0.008). Caspase 1 and TNF-alpha gene expression were increased in all brain tissues and p53 gene expression was decreased in only hippocampus tissue in dose group. Short-term exposure to dichlorvos leads to neuronal loss in hippocampus and TNF-alpha rapidly and potently induces apoptosis and also several caspases as possible participants in the apoptotic cascade.

The aim of this study was to provide a methodology to make a clear distinction between malignant tumors and morphologically similar benign processes, by examining the expression of EGFR, VEGF, HIF1-α, survivin, Bcl-2 and p53 proteins. Four groups of patient samples were studied: group 1, low-grade astrocytomas (WHO grades I-II) (n=6); group 2, peripheral area of high-grade astrocytomas (WHO grades III-IV) (n=5); group 3, gliomatosis cerebri (n=11); and group 4, reactive gliosis (n=6). Tissue arrays (TAs) were designed to study apoptosis, angiogenesis and invasion-related proteins by immunohistochemistry (IHC). By means of non-parametric analysis (Mann-Whitney U test), EGFR staining was shown to be significantly lower in reactive gliosis than in the low- and high-grade astrocytomas (p=0.015 and p=0.030, respectively); Bcl-2 immunoreactivity was significantly higher in the gliomatosis cerebri samples than in the reactive processes (p=0.005); and finally, Bcl-2 presented significantly lower expression levels in reactive gliosis compared to the peripheral areas of high-grade astrocytomas (p=0.004). The results indicate that Bcl-2 and EGFR may be useful in conducting differential diagnosis between the above groups, while the expression of the remaining antibodies does not appear to aid in distinguishing between the samples analyzed. The use of TAs to identify the protein expression profiles of biological markers related to different pathways was verified, and its potential as a discriminatory technique for everyday pathology procedures was demonstrated.

The role of p73, the homologue of the tumor suppressor p53, in regulating angiogenesis has recently been extensively investigated, resulting in the publication of five articles. Of these, two studies suggested a suppressive role, while the others implied a stimulatory role for the p73 isoforms in regulating angiogenesis. A negative role for TAp73, the full-length form that is often associated with tumor suppression, in blood vessel formation, is consistent with its general attributes and was proposed to be effected indirectly through the degradation of hypoxia-inducible factor 1α (HIF1-α), the master angiogenic regulator. In contrast, a positive role for TAp73 coincides with its recently understood role in supporting cellular survival and thus tumorigenesis, consistent with TAp73 being not-mutated but rather often overexpressed in clinical contexts. In the latter case, TAp73 expression was induced by hypoxia via HIF1-α, and it appears to directly promote angiogenic target gene activation and blood vessel formation independent of HIF1-α. This mini review will provide an overview of these seemingly opposite recent findings as well as earlier data, which collectively establish the definite possibility that TAp73 is indeed capable of both promoting and inhibiting angiogenesis, depending on the cellular context.

Hypoxia refers to the decrease in oxygen tension in the tissues, and the central effector of the hypoxic response is the transcription factor Hypoxia-Inducible Factor α (HIF1-α). Transient hypoxia in acute events, such as exercising or regeneration after damage, play an important role in skeletal muscle physiology and homeostasis. However, sustained activation of hypoxic signaling is a feature of skeletal muscle injury and disease, which can be a consequence of chronic damage but can also increase the severity of the pathology and worsen its outcome. Here, we review evidence that supports the idea that hypoxia and HIF-1α can contribute to the establishment of fibrosis in skeletal muscle through its crosstalk with other profibrotic factors, such as Transforming growth factor β (TGF-β), the induction of profibrotic cytokines expression, as is the case of Connective Tissue Growth Factor (CTGF/CCN2), or being the target of the Renin-angiotensin system (RAS).

BACKGROUND

In this study, we evaluate whether the use of biliverdin (BV), a natural non-toxic antioxidant product of haeme catabolism, can suppress head and neck squamous cell carcinoma (HNSCC) cell proliferation and improve the tumour survival both in vitro and in vivo. Furthermore, we investigate whether this therapeutic outcome relies on BV's potent antioxidant effect on reactive oxygen species (ROS)-mediated signalling.

METHODS

Two well-characterised HNSCC cell lines and a mouse model with human HNSCC were used for this study. In vitro, the effect of BV on ROS was assayed. Subsequently, critical regulatory proteins involved in growth, antiapoptotic, and angiogenic pathways were investigated by western blot analysis. In addition, the antiproliferative effect of BV was also evaluated using the clonogenic assay. Moreover, tumour growth inhibition was assessed using a mouse model with HNSCC.

RESULTS

Biliverdin treatment resulted in decreased ROS, leading to suppression of proliferation and angiogenesis pathways of HNSCC, significantly decreasing the expression and phosphorylation of oncogenic factors such as epidermal growth factor receptor (EGFR), phosphorylation of Akt, and expression of angiogenic marker and transcription factor, hypoxia-inducible factor1-α (HIF1-α). Furthermore, this downregulation of ROS by BV led to a significant suppression of tumour growth in vivo.

CONCLUSIONS

Our study demonstrates the efficacy of a novel therapeutic approach using BV as an antitumour agent against HNSCC through its effect on EGFR/Akt and HIF1-α/angiogenesis signal transduction pathways. Our findings indicate that BV's inhibitory effect on these tumorigenic pathways relies on its antioxidant effect, and may extend its therapeutic potential to other solid cancers.

Non-small cell lung cancer (NSCLC), comprising 85% of lung cancer cases, has been associated with resistance to chemo/radiotherapy. The hypoxic tumor micro-environment, where insufficient vasculature results in poor drug penetrance and sub-optimal chemotherapy in the tumor interiors contributes heavily to this resistance. Additionally, epigenetic changes in tumorigenic cells also change their response to different forms of therapy. In our study, we have investigated the effectiveness of a combination of cisplatin with scriptaid [a pan-Histone Deacetylase inhibitor (HDACi)] in a model that mimics the tumor microenvironment of hypoxia and sub-lethal chemotherapy. Scriptaid synergistically increases the efficacy of cisplatin in normoxia as well as hypoxia, accompanied with reduced metastasis and enhanced DNA damage. Addition of scriptaid also overcomes the cisplatin resistance exhibited in lung cancer cells with stabilized hypoxia inducible factor 1 (HIF1)-α (mutant) and mutant p53. Molecular studies showed that the combination treatment increased apoptotic cell death in both normoxia and hypoxia with a dual role of p38MAPK. Together, our results suggest that the combination of low dose cisplatin and scriptaid is cytotoxic to NSCLC lines, can overcome hypoxia induced resistance and mutant p53- induced instability often associated with this cancer, and has the potential to be an effective therapeutic modality.

High-intensity exercise/training, especially interval exercise/training, has gained popularity in recent years. Hypoxic training was introduced to elite athletes half a century ago and has recently been adopted by the general public. In the current review, we have summarised the molecular adaptive responses of skeletal muscle to high-intensity exercise/training, focusing on mitochondrial biogenesis, angiogenesis, and muscle fibre composition. The literature suggests that (peroxisome proliferator-activated receptor gamma coactivator 1-alpha) PGC-1α, vascular endothelial growth factor (VEGF), and hypoxia-inducible factor 1-alpha (HIF1-α) might be the main mediators of skeletal muscle adaptations to high-intensity exercises in hypoxia. Exercise is known to be anti-inflammatory, while the effects of hypoxia on inflammatory signalling are more complex. The anti-inflammatory effects of a single session of exercise might result from the release of anti-inflammatory myokines and other cytokines, as well as the downregulation of Toll-like receptor signalling, while training-induced anti-inflammatory effects may be due to reductions in abdominal and visceral fat (which are main sources of pro-inflammatory cytokines). Hypoxia can lead to inflammation, and inflammation can result in tissue hypoxia. However, the hypoxic factor HIF1-α is essential for preventing excessive inflammation. Disease-induced hypoxia is related to an upregulation of inflammatory signalling, but the effects of exercise-induced hypoxia on inflammation are less conclusive. The effects of high-intensity exercise under hypoxia on skeletal muscle molecular adaptations and inflammatory signalling have not been fully explored and are worth investigating in future studies. Understanding these effects will lead to a more comprehensive scientific basis for maximising the benefits of high-intensity exercise.

Keywords: high-intensity exercise; hypoxia; inflammatory signalling; skeletal muscle; training.

Intestinal ischemia/reperfusion (I/R) can lead to tissue damage associated with inflammation and mucosal apoptosis. Ischemic postconditioning (IPostC), a series of repeated, brief, intermittent periods of ischemia and reperfusion, has beneficial effects against I/R-induced injury in the heart and intestine, although the underlying mechanisms for these effects remain unclear. We evaluated the involvement of microRNA-21 (miR-21) in the protective effects of IPostC in a rat model of I/R induced by superior mesenteric artery occlusion and reopening. IPostC decreased I/R injury and suppressed apoptosis in the intestinal tissues concomitant with the induction of hypoxia inducible factor 1 alpha (HIF-1α) and the upregulation of miR-21. In vitro experiments in the intestinal epithelial cell line IEC-6 showed that hypoxia induced miR-21 and this effect was abolished by silencing HIF1-α, confirming the induction of miR-21 by HIF1-α, HIF1-α or miR-21 inhibition exacerbated I/R induced apoptosis, and programmed cell death 4 (PDCD4) and Fas-L was involved in miR-21 mediated anti-apoptotic effects on intestinal epithelial cells. Knockdown of miR-21 or inhibition of HIF1-α abolished the IPostC-mediated attenuation of intestinal injury and apoptosis and the downregulation of PDCD4 and Fas-L. A potential mechanism underlying the protective effect of IPostC may therefore involve the induction of miR-21 by HIF1-α and the attenuation of apoptosis via the downregulation of PDCD4 and Fas-L.

OBJECTIVE

How is vascular endothelial growth factor (VEGF) expression regulated by hypoxia inducible factor 1 alpha (HIF1A) during menstruation?

CONCLUSIONS

After progesterone (P4) withdrawal, HIF1A was activated and it directly up-regulated VEGF mRNA expression and this regulation was the highest during endometrium breakdown in the mouse menstrual-like model.

BACKGROUND

VEGF, an important angiogenic factor, is known to be essential for endometrial repair, particularly in angiogenesis and re-epithelialization. However, its upstream regulation has not been fully clarified. HIF1 is the first transcription factor response to hypoxia and is closely associated with angiogenesis; it is also an upstream regulator of VEGF mRNA.

METHODS

We investigated the changes in the expression of HIF1A and VEGF after P4 withdrawal and after HIF1A inhibition. The total number of mice used was 62. The treatment duration in the mouse menstrual-like model was 8 days.

METHODS

The mouse menstrual-like model and mouse and human decidual endometrial stromal cells were established to mimic menstruation. Protein and mRNA expressions of HIF1A and VEGF were investigated by immunohistochemistry, Western blot and quantitative PCR. The direct interaction between HIF1A and the Vegf promoter was also investigated by chromatin immunoprecipitation. HIF1A inhibition in vivo and in vitro was achieved by administration of an HIF1A inhibitor and by siRNA knockdown, respectively.

RESULTS

HIF1A was translocated to the nucleus from 8 to 16 h after P4 withdrawal, while VEGF mRNA expression was the highest at 12 h. HIF1A directly bound to Vegf promoter during endometrial breakdown, which peaked at 12 h. HIF1A inhibition suppressed VEGF mRNA and protein expression in the mouse menstrual-like model and decidualized stromal cells. Inhibition of HIF1A also suppressed endometrial breakdown.

CONCLUSIONS

Although HIF1A regulation of VEGF mRNA was confirmed in the mouse menstrual-like model and decidual endometrium stromal cells, the functional regulation of VEGF protein was not further determined.

CONCLUSIONS

Here, we report that the functional regulation of VEGF was complicate in menstruation. We also report that HIF1A plays a key role in endometrial breakdown.

BACKGROUND

The National Nature Science Foundation of China (No. 30901608), the National Basic Research Program of China (2010CB530403) and the National Science and Technology Support Program (No. 2012BAI32B05). The authors have no conflicts of interest to disclose.

BACKGROUND

This study is not a clinical trial.

Angiogenesis is implicated in a variety of human pathologies and may also play a role in the progression of heart failure. We have studied the expression of members of the vascular endothelial growth factor (VEGF) and the angiopoietin families and their receptors in mice lacking the mitochondrial transcription factor A. These mice lack functional respiratory chain activity in their myocytes and develop dilated cardiomyopathy (DCM) postnatally. We studied the hearts of the knockout mice by in situ hybridization, Western blotting analysis, and immunohistochemistry. VEGF-A mRNA and protein levels were elevated in the myocardium of the knockouts. Levels of the hypoxia inducible transcription factor 1 alpha (HIF1 alpha) and of glyceraldehyde-3-phosphate dehydrogenase transcripts were also increased, whereas those of angiopoietin-1 and -2 were reduced. Despite the striking upregulation of VEGF-A, there was no increase in capillary density in the knockout hearts. This study suggests that a disturbance in angiogenesis may contribute to the pathogenesis of DCM.

Isoflurane alleviates the inflammatory response in endotoxin-induced acute lung injury (ALI). In this study, we investigated the protective mechanism of isoflurane postconditioning in lipopolysaccharide (LPS)induced ALI. Exposure to isoflurane decreased miR-155 and upregulated HIF-1 alpha and HO-1 mRNA and protein. The effects of isoflurane on HIF-1 alpha mRNA and protein could be inhibited by overexpression of miR-155. Furthermore, mice overexpressing miR-155 had higher levels of TNF-alpha and IL-1 beta in BALF when exposed to isoflurane after LPS challenge.Conversely, downregulation of miR-155 promoted isoflurane effects on HIF-1 alpha expression. These results suggest that isoflurane posttreatment hr alleviates LPS-induced ALI and cell injury by triggering miR-155-HIF-1 alpha pathway, leading to upregulation of HO-1.

Fucosterol is a phytosterol commonly extracted from algae. It has been proved that fucosterol possesses antioxidant activity that is capable of scavenging the free radicals causing skin damages. In this study, we investigated the protective mechanisms of fucosterol on cobalt chloride (CoCl2) induced hypoxia damages to keratinocytes (HaCaT). We found that fucosterol inhibited CoCl2 induced cytotoxicity and inflammation in a dose-dependent manner. Furthermore, fucosterol attenuated CoCl2 induced excess expression of IL-6, IL-1β and TNF-α in HaCaT cells. In addition, fucosterol surpressed the phosphorylation of PI3K and Akt and accumulation of HIF1-α simulated by CoCl2. Taken together, these results suggested that fucosterol executed its protective effects against CoCl2 induced cytotoxicity and inflammation by the inhibition of hypoxia inducible factor through PI3K/Akt pathway.

Calorie restriction (CR) leads to a remarkable decrease in adipose tissue mass and increases longevity in many taxa. Since the discovery of leptin, the secretory abilities of adipose tissue have gained prominence in the responses to CR. We quantified transcripts of epididymal white adipose tissue of male C57BL/6 mice exposed to graded levels of CR (0-40% CR) for 3 months. The numbers of differentially expressed genes (DEGs) involved in NF-κB, HIF1-α, and p53 signaling increased with increasing levels of CR. These pathways were all significantly downregulated at 40% CR relative to 12 h ad libitum feeding. In addition, graded CR had a substantial impact on DEGs associated with pathways involved in angiogenesis. Of the 497 genes differentially expressed with graded CR, 155 of these genes included a signal peptide motif. These putative signaling proteins were involved in the response to ketones, TGF-β signaling, negative regulation of insulin secretion, and inflammation. This accords with the previously established effects of graded CR on glucose homeostasis in the same mice. Overall these data suggest reduced levels of adipose tissue under CR may contribute to the protective impact of CR in multiple ways linked to changes in a large population of secreted proteins.

BACKGROUND

Neutral endopeptidase (NEP) is a transmembrane cell surface peptidase present on prostatic epithelial cells that catalytically inactivates small peptide substrates. Neutral endopeptidase loss is associated with prostate cancer growth, progression, and increased angiogenesis. We examined whether NEP expression is regulated by hypoxia, frequently encountered in the tumor microenvironment.

METHODS

NEP expression was compared in prostate cancer cell lines cultured in normoxic and hypoxic conditions. The NEP activity, protein levels, and mRNA levels were determined using enzyme assay, Western blotting and q-PCR analysis, respectively. Electrophoretic mobility shift assay and chromatin immunoprecipitation assay (ChIP) was used to confirm the negative regulation of NEP at the transcriptional level by hypoxia responsive elements (HREs).

RESULTS

The results indicate that NEP expression was inhibited under hypoxic conditions in the NEP positive LNCaP, C4-2, and 22RV1 cells and human umbilical vascular endothelial (HUVEC) cells. NEP regulation appeared to be predominantly at the transcriptional level as NEP mRNA expression significantly reduced with hypoxia, concordant with the kinetics of protein levels, and NEP enzyme activity. A search of the NEP gene sequence revealed three putative HREs upstream of the NEP promoter. Two of the HREs demonstrated a specific reduction of shift in the presence of cobalt chloride; specificity of the binding sites was confirmed by ChIP.

CONCLUSIONS

Our data indicate a novel mechanism where hypoxia negatively regulates the tumor suppressor function of NEP in prostate cancer. The negative regulation of NEP is mediated by binding of the HIF1-α protein binding to the HREs present upstream of the NEP promoter.

Cadmium (Cd) is a heavy metal and environmental toxin. Exposure to Cd has been associated with a variety of human cancers. In this study, we performed in vitro assays to examine the effects of cadmium chloride (CdCl₂) on A549 cells, a human lung adenocarcinoma cell line. Cd does not affect proliferation, migration, or apoptosis of A549 cells at concentrations of 0.1-10 μM. At 0.5 and 1 μM, Cd increases the expression of vascular endothelial growth factor (VEGF) (p < 0.05, p < 0.01, respectively), but not basic fibroblast growth factor (b-FGF) in A549 cells. The conditioned media were collected from the A549 cells treated with 1 μM Cd and were co-cultured with human umbilical vein endothelial cells (HUVECs). Upon treatment with the conditioned media, the proliferation and migration of HUVECs significantly increased (p < 0.01, p < 0.05, respectively), while apoptosis remained unchanged. In addition, 1 μM Cd increases the level of hypoxia inducible factor 1-α (HIF1-α), which is a positive regulator of VEGF expression. Although low-dose Cd does not directly affect the growth of lung adenocarcinoma cells, it might facilitate the development of tumors through its pro-angiogenic effects.

Survivin, an inhibitor of apoptosis protein family, appears to be involved in tumor progression and angiogenesis. The current study contains rare reports on the transcriptional regulation of survivin expression in retinal neovascularization (NV). The aim of this study was to investigate hypoxia-inducible factor-1α (HIF-1α) and survivin expression in pathologic ocular angiogenesis and to determine their correlation and cellular location. The model of oxygen-induced retinopathy (OIR) was induced in C57BL/6 mice by exposing 75% oxygen from postnatal day 7 (p7) to p12 and then followed by room air. Fluorescence angiography, immunostaining and HE staining were used to assess the visualization of retinal vascularization and the expression of HIF-1α and survivin protein in retina oxygen-induced retinopathy was characterized by clusters of neovascularization and regions of non-perfusion. HIF-1α and survivin were both highly expressed in OIR and a positive correlation existed between HIF-1α and survivin expression. In OIR, there was more HIF1-α protein expression in the inner nuclear layer (INL), the ganglion cell layer (GCL), and more neovascularization breaking through the inner retina and survivin protein was detected in GCL, and more neovascularization breaking through the inner retina. Our study had shown that both HIF1-α and survivin are involved in the retinal neovaccularization. Meanwhile HIF1-α and survivin have differential cellular location in retinal ischemia, and HIF1-α might be a critical transcription factor involved in the regulation of survivin expression.

Hypoxia provokes metabolism misbalance, mitochondrial dysfunction and oxidative stress in both human and animal cells. However, the mechanisms which hypoxia causes mitochondrial dysfunction and energy metabolism misbalance still remain unclear. In this study, we presented evidence that mitochondrial phosphatase Ptpmt1 is a hypoxia response molecule that regulates cell proliferation, survival and glucose metabolism in human erythroleukemia TF-1 cells. Exposure to hypoxia or DFO treatment results in upregulation of HIF1-α, HIF-2α and Ptpmt1. Only inhibition of HIF-2α by shRNA transduction reduces Ptpmt1 expression in TF-1 cells under hypoxia. Ptpmt1 inhibitor suppresses the growth and induces apoptosis of TF-1 cells. Furthermore, we demonstrated that Ptpmt1 inhibition reduces the Glut1 and Glut3 expression and decreases the glucose consumption in TF-1 cells. In additional, Ptpmt1 knockdown also results in the mitochondrial dysfunction determined by JC1 staining. These results delineate a key role for HIF-2α-induced Ptpmt1 upregulation in proliferation, survival and glucose metabolism of erythroleukemia cells. It is indicated that Ptpmt1 plays important roles in hypoxia-induced cell metabolism and mitochondrial dysfunction.

Erythropoietin receptors (EpoRs) are expressed in a large percentage of cells in many human malignancies, including endometrial adenocarcinoma. In such tumors, administration of recombinant human erythropoietin (rhEpo) during radiotherapy and chemotherapy may oppose tumor progression by interfering with growth and invasion pathways. In the present study, a strong EpoR expression was demonstrated in 58.8% of 72 stage I endometrial adenocarcinomas, and this pattern was linked with a high degree of tumor differentiation (p=0.01), deep myometrial invasion (p=0.04) and, marginally, with poor prognosis (p=0.06). In addition, a strong association with the immunohistochemical expression of hypoxia-inducible factor 1alpha (HIF1alpha) and the downstream angiogenic protein vascular endothelial growth factor (VEGF) was noted. In multivariate analysis, HIF1alpha, but not EpoR, was associated with the depth of myometrial invasion (p=0.04) and marginally with prognosis (p=0.07). It is concluded that EpoR are common constituents of endometrial adenocarcinomas and are related to tumor aggressiveness, although this is probably a result of their involvement in an active HIF pathway.

Many consolidated findings have revealed that cancer formation resembles events of embryonic development. In particular, the network of transcription factors and adhesion molecules is very similar when comparing neural crest-derived melanoblasts and melanoma cells. The main difference is found in the manifestation of distinct genes in melanoma, whereas in neural crest cells gene expression is tightly regulated to promote either a migratory or stationary phenotype. We established a cell culture system to generate melanoblast-related cells (MBrc) out of melanocytes as originally described by Cook et al. First, we confirmed the typical gene expression pattern of BRN-2, SOX10, PAX3 and EDNRB. Furthermore, we identified enhanced migration and proliferation similar to that of melanoma cells. Our intention of using this system was to classify the known 'melanoma-associated genes' into a subgroup of genes solely regulated by the differentiation process and a second subgroup that is unaffected by differentiation and is potentially important to the stabilization of a melanoma phenotype. The expression of melanoma-associated genes (N-cadherin, MUC-18, integrin β3, αααv, SLUG, TBX3, HIF1-α, BMP-4 and bFGF) was enhanced in MBrc which were de-differentiated out of melanocytes. E-cadherin, H-cadherin and β-catenin, prevalently found to be downregulated in melanoma, were diminished in MBrc. Remarkably, the transcription factor SNAIL was unaffected by differentiation and could be one key molecule in early melanoma development that is of prevailing importance. In summary, we feel that the analysis of MBrc generated in a reproducible system will give new insight into the role and importance of melanoma-associated genes.

Bone marrow mesenchymal stromal cells (BMMSCs) are cardioprotective in acute myocardial infarction (AMI) because of release of paracrine angiogenic and prosurvival factors. Hypoxia-inducible factor 1-α (HIF1-α), rapidly degraded during normoxia, is stabilized during ischemia and upregulates various cardioprotective genes. We hypothesized that BMMSCs engineered to overexpress mutant, oxygen-resistant HIF1-α would confer greater cardioprotection than nontransfected BMMSCs in sheep with AMI.

Allogeneic BMMSCs transfected with a minicircle vector encoding mutant HIF1-α (BMMSC-HIF) were injected in the peri-infarct of sheep (n=6) undergoing coronary occlusion. Over 2 months, infarct volume measured by cardiac magnetic resonance (CMR) imaging decreased by 71.7±1.3% (P<0.001), and left ventricular (LV) percent ejection fraction (%EF) increased near 2-fold (P<0.001) in the presence of markedly decreased end-systolic volume. Sheep receiving nontransfected BMMSCs (BMMSC; n=6) displayed less infarct size limitation and percent LVEF improvement, whereas in placebo-treated animals (n=6), neither parameters changed over time. HIF1-α-transfected BMMSCs (BMMSC-HIF) induced angio-/arteriogenesis and decreased apoptosis by HIF1-mediated overexpression of erythropoietin, inducible nitrous oxide synthase, vascular endothelial growth factor, and angiopoietin-1. Cell tracking using paramagnetic iron nanoparticles in 12 additional sheep revealed enhanced long-term retention of BMMSC-HIF.

Intramyocardial delivery of BMMSC-HIF reduced infarct size and improved LV systolic performance compared to BMMSC, attributed to increased neovascularization and cardioprotective effects induced by HIF1-mediated overexpression of paracrine factors and enhanced retention of injected cells. Given the safety of the minicircle vector and the feasibility of BMMSCs for allogeneic application, this treatment may be potentially useful in the clinic.

Hypoxia is a common characteristic of solid tumors. Recent studies confirmed that phospholipase D2 (PLD2) plays significant roles in cancer progression. In this study, correlation between the expression of PLD2 and the change in the protein level of hypoxia-inducible factor 1-alpha (HIF1-α) was studied. Thirty human colon cancer tissues were examined for the expression of HIF1-α and PLD2 protein, and mRNA levels. SW480 and SW620 cells were exposed to normoxia (20 %) or hypoxia (<1 %). HIF1-α and PLD2 protein, and mRNA levels were analyzed by Western blot and qRT-PCR, respectively. Growth studies were conducted on cells with HIF1-α inhibition through xenograft tumor model. Finally, PLD2 protein was detected by Western blot analysis in vivo. There was a positive correlation between HIF1-α and PLD2 in colon cancer tissues. Hypoxic stress induced PLD2 mRNA and protein expression in SW480 and SW620 cells. Cells transfected with HIF1-α siRNA showed attenuation of hypoxia stress-induced PLD2 expression. In vivo growth decreased in response to HIF1-α and PLD2 inhibition. These results suggest that PLD2 expression in colon cancer cells is up-regulated via HIF1-α in response to hypoxic stress and underscores the crucial role of HIF1-α-induced PLD2 in tumor growth.