Hypoxia-inducible erythropoietin signaling in squamous dysplasia and squamous cell carcinoma of the uterine cervix and its potential role in cervical carcinogenesis and tumor progression

Targeting Stress Erythropoiesis Pathways in Cancer

Cancer-related anemia (CRA) is a common multifactorial disorder that adversely affects the quality of life and overall prognosis in patients with cancer. Safety concerns associated with the most common CRA treatment options, including intravenous iron therapy and erythropoietic-stimulating agents, have often resulted in no or suboptimal anemia management for many cancer patients. Chronic anemia creates a vital need to restore normal erythropoietic output and therefore activates the mechanisms of stress erythropoiesis (SE). A growing body of evidence demonstrates that bone morphogenetic protein 4 (BMP4) signaling, along with glucocorticoids, erythropoietin, stem cell factor, growth differentiation factor 15 (GDF15) and hypoxia-inducible factors, plays a pivotal role in SE. Nevertheless, a chronic state of SE may lead to ineffective erythropoiesis, characterized by the expansion of erythroid progenitor pool, that largely fails to differentiate and give rise to mature red blood cells, further aggravating CRA. In this review, we summarize the current state of knowledge on the emerging roles for stress erythroid progenitors and activated SE pathways in tumor progression, highlighting the urgent need to suppress ineffective erythropoiesis in cancer patients and develop an optimal treatment strategy as well as a personalized approach to CRA management.

Infection by High-Risk Human Papillomaviruses, Epithelial-to-Mesenchymal Transition and Squamous Pre-Malignant or Malignant Lesions of the Uterine Cervix: A Series of Chained Events?

Wound healing requires static epithelial cells to gradually assume a mobile phenotype through a multi-step process termed epithelial-to-mesenchymal transition (EMT). Although it is inherently transient and reversible, EMT perdures and is abnormally activated when the epithelium is chronically exposed to pathogens: this event deeply alters the tissue and eventually contributes to the development of diseases. Among the many of them is uterine cervical squamous cell carcinoma (SCC), the most frequent malignancy of the female genital system. SCC, whose onset is associated with the persistent infection of the uterine cervix by high-risk human papillomaviruses (HR-HPVs), often relapses and/or metastasizes, being resistant to conventional chemo- or radiotherapy. Given that these fearsome clinical features may stem, at least in part, from the exacerbated and long-lasting EMT occurring in the HPV-infected cervix; here we have reviewed published studies concerning the impact that HPV oncoproteins, cellular tumor suppressors, regulators of gene expression, inflammatory cytokines or growth factors, and the interactions among these effectors have on EMT induction and cervical carcinogenesis. It is predictable and desirable that a broader comprehension of the role that EMT inducers play in SCC pathogenesis will provide indications to flourish new strategies directed against this aggressive tumor.

AKT/GSK-3β/β-catenin signaling pathway participates in erythropoietin-promoted glioma proliferation

PURPOSE

Although erythropoietin (EPO) has been proven to significantly promote the proliferation of cancer cells, the mechanism for promoting glioma proliferation is poorly understood. Here, we examined the functional role of the AKT/GSK-3β/β-catenin signaling pathway in the EPO-mediated proliferation of glioma.

METHODS

The distribution of EPO and Ki-67 among clinical samples with different WHO grades was plotted by Immunological Histological Chemistry analysis. U87 and U251 glioma cell lines were treated with short hairpin RNA targeting (shEPO), recombinant human erythropoietin (rhEPO) and/or AKT-specific inhibitor (MK-2206). The changes in phosphorylated AKT, nuclear β-catenin, cyclin D1 and p27kip1 expression were detected. Cell cycle distributions and glioma proliferation in vitro and in vivo were analyzed.

RESULTS

The expression level of EPO was significantly elevated with the increase of WHO grade and Ki67 in clinical glioma specimens. In vitro, knockdown of endogenous EPO in U87 and U251 cells effectively block the phosphorylation of AKT and GSK-3β and the expression of nuclear β-catenin. shEPO treatment also significantly decreased the expression of cyclin D1 and increased the expression of p27kip1. The cell cycle transition then slowed down and the proliferation of glioma cells or mouse xenograft tumors both decreased. Treatment of cells or tumors with extra rhEPO reversed the above biological effects mediated by shEPO. rhEPO-induced activation of the AKT/GSK-3β/β-catenin pathway and proliferation were abolished by MK-2206.

CONCLUSIONS

Our study identified the AKT/GSK-3β/β-catenin axis as a critical mediator of EPO-induced glioma proliferation and further provided a clinically significant dimension to the biology of EPO.

Role of the erythropoietin receptor in Lung Cancer cells: erythropoietin exhibits angiogenic potential

Background: Recombinant human erythropoietin (rHuEPO), a hormone regulating the proliferation and differentiation of erythroid cells, is one of the prescription drugs used to treat cancer-associated anemia. However, administration of rHuEPO to cancer patients has been reported to be associated with decreased survival, and the mechanism by which it acts remains controversial. The present study aimed to investigate the expression of the EPO-receptor in lung cancer cell lines and whether rHuEPO treatment affected its growth and migration. Moreover, the angiogenic effects of rHuEPO were also explored in vivo.

Methods: Expression of the EPO-receptor in lung cancer cell lines was measured by Western blotting and enzyme linked immunosorbent assays (ELISAs). Proliferation of the lung cancer cells was monitored in the presence of rHuEPO. Human umbilical vein endothelial cells (HUVECs) were used for tube formation assays in vitro, and transwell migration assays were performed to detect migration under rHuEPO treatment. Matrigel plug technology was employed to observe the angiogenic effects in both nude mice and Matrigel-containing lung cancer cell lines H838 or H1975. Microvessel density (MVD) was measured using CD31 Immunohistochemistry (IHC) staining.

Results: EPO-receptor (EPO-R) was only detected in the cell lines H838 and H1339 by ELISA. However, the EPO-R protein was detected in all cell lines by Western blotting, which is in contradiction to the ELISA results. Proliferation and migration were not affected by rHuEPO treatment. However, rHuEPO promoted HUVEC tube formation in vitro and significantly induced the formation of new blood vessels in vivo. Furthermore, rHuEPO did not antagonize the inhibitory effects of Afatinib (epidermal growth factor receptor-tyrosine kinase inhibitor; EGFR-TKI) in simultaneous treatment with rHuEPO. In a 3D cell co-culture model, rHuEPO did not enhance the secretion of vascular endothelial growth factor (VEGF) in lung cancer cells or human lung fibroblast cell line MRC-5.

Conclusions: We have shown that the role of EPO goes beyond erythropoiesis, also playing a strong role in angiogenesis by participating in new blood vessel formation in lung cancer models. Thus, rHuEPO may raise the risk of thrombosis and metastasis in vivo. Additionally, our results suggest that studies using commercially available EPO-R antibodies should be reexamined; some of these antibodies may not in fact recognize EPO-R.

Antiangiogenic effects of the chemopreventive agent tributyrin, a butyric acid prodrug, during the promotion phase of hepatocarcinogenesis

Agents that inhibit angiogenic factors may prevent the development of hepatocellular carcinoma (HCC). Thus, the objective of this study was to kinetically evaluate the antiangiogenic activity of tributyrin (TB), a butyric acid prodrug, in the promotion stage of hepatocarcinogenesis. For this purpose, the resistant hepatocyte (RH) model was used for induction of preneoplastic lesions in Wistar rats. During the promotion phase, the animals received TB or maltodextrin (MD) as control daily. The rats were killed at three time-points (P1, P2 and P3). Increased expression of Vegfa and Vegfr2 was observed during promotion phase of hepatocarcinogenesis, which was not reversed by TB treatment. However, TB treatment reduced the expression of cluster of differentiation (CD) 34-positive vessels at P3 and α-smooth muscle actin (α-SMA)-positive vessels at P2 compared with MD. Enhanced levels of hypoxia inducible factor-1α (HIF-1α) and phosphorylated extracellular signal-regulated kinases (pERK) were detected at P3 when compared with P1 and P2 in the MD treatment. TB treatment reduced the levels of HIF-1α and pERK at P3 relative to the MD control. Experiments with human umbilical vein endothelial cells (HUVEC) showed that sodium butyrate (NaBu) inhibited cell migration and tube formation, confirming the antiangiogenic activity of its prodrug TB. In conclusion, antiangiogenic activity of TB is an early event that already occurs in preneoplastic livers, reinforcing its potential chemopreventive effects against HCC.

Vasculogenic Mimicry Formation Is Associated with Erythropoietin Expression but Not with Erythropoietin Receptor Expression in Cervical Squamous Cell Carcinoma

Background

Vasculogenic mimicry (VM), as an endothelium-independent cancer microcirculation, has been observed in many malignancies including cervical cancer. Erythropoietin (EPO) and erythropoietin receptor (EPO-R) could produce an angiogenic effect to promote cervical squamous cell carcinoma (CSCC) progression. However, the association between VM formation and EPO/EPO-R expression in CSCC is poorly explored.

Methods

Seventy-six paraffin-embedded CSCC samples, 25 high-grade squamous intraepithelial lesion (HSIL) samples, 20 low-grade squamous intraepithelial lesion (LSIL) samples, and 20 normal cervix samples were collected. Immunohistochemistry SP method was performed to detect EPO/EPO-R expression and CD31/periodic acid-Schiff (PAS) double staining was performed to detect VM formation. The associations of EPO/EPO-R and VM with clinicopathological parameters of CSCC were analyzed. The associations between VM formation and EPO/EPO-R expression were also analyzed.

Results

The positive expression rates of EPO and EPO-R were gradually increasing along the progression of normal cervix-LSIL-HSIL-CSCC sequence (P<0.05). EPO and EPO-R expression were not significantly associated with clinicopathological parameters of CSCC patients (P>0.05). VM was significantly associated with FIGO stage, lymphovascular space involvement, and lymph node metastasis (P<0.05). VM was positively associated with EPO expression (r=0.284, P<0.05) but was not associated with EPO-R expression (P>0.05).

Conclusion

These data suggest that increased EPO/EPO-R expression may play an important role in cervical carcinogenesis. EPO overexpression may promote VM formation in CSCC.

Exosomes derived from hypoxic epithelial ovarian cancer cells deliver microRNAs to macrophages and elicit a tumor-promoted phenotype

Recently, cancer has been considered to be a complex system that includes the tumor microenvironment (TME). Tumor-associated macrophages (TAMs) are the most common immune-related stromal cells in the TME, and communication between cancer cells and TAMs is crucial for the progression of epithelial ovarian cancer (EOC). In this study, we revealed that exosomes derived from EOC cells remodel macrophages to a tumor-promoted phenotype, namely TAMs. In addition, hypoxic microenvironments have been postulated to facilitate this process in the TME, and hypoxia-inducible factors (HIFs) play an important role in this process. We found that TAMs educated by hypoxic exosomes derived from EOC cells promote tumor proliferation and migration in a feedback loop. Based on microarray analysis of normoxic and hypoxic exosomes, we discovered that a panel of miRNAs was enriched in hypoxic exosomes. And these three highly expressed miRNAs were induced by hypoxia via HIFs. In this study, we revealed that under hypoxic conditions, EOC cell-derived exosomes deliver miRNAs to induce M2 macrophage polarization, which promotes EOC cell proliferation and migration. This study suggests that these exosomes and associated miRNAs might serve as targets for novel treatments or diagnostic biomarkers for EOC.

An Apparent Correlation Between Central Nervous System and Kidney's Erythropoietin and TNF Alpha Expression at Peak Experimental Autoimmune Encephalomyelitis Disease

Experimental autoimmune encephalomyelitis (EAE) is an inflammatory demyelination disease associated with inflammatory reactions and attenuation of antioxidant capacity. Several lines of evidence show that organs such as the liver and kidneys can share their antioxidant activity to protect the central nervous system (CNS) against neurodegenerative diseases. The aim of this study was to examine the possible interplay of the kidneys and CNS in pathogenesis of EAE. For this purpose, EAE model was induced in C57BL/6 mice, and expression of erythropoietin (EPO), TNF-α, and NFκB-1 was determined in the kidney and CNS at early and peak stages of the disease. Besides, changes in serum level of EPO and total antioxidant capacity (TAC) were measured by different clinical scores. Real-time PCR (qPCR) results showed a substantial increase in TNF-α and NFκB-1 expression in mice at EAE peak stage compared to sham (control). There was a positive correlation between kidney-EPO and CNS-inflammatory factor expression in EAE-induced mice. In general, EPO expression was relatively higher in the kidneys compared to CNS tissue in sham group. There was a significant upregulation in expression of EPO in the brain, spinal cord, and kidneys particularly at peak stage. Accordingly, changes in serum TAC were consistent with serum EPO concentration. This data may suggest that there is an EPO-mediated cross-talk between the kidney and CNS during EAE pathogenesis.

Generation of erythroid cells from polyploid giant cancer cells: re-thinking about tumor blood supply

INTRODUCTION

During development and tumor progression, cells need a sufficient blood supply to maintain development and rapid growth. It is reported that there are three patterns of blood supply for tumor growth: endothelium-dependent vessels, mosaic vessels, and vasculogenic mimicry (VM). VM was first reported in highly aggressive uveal melanomas, with tumor cells mimicking the presence and function of endothelial cells forming the walls of VM vessels. The walls of mosaic vessels are randomly lined with both endothelial cells and tumor cells. We previously proposed a three-stage process, beginning with VM, progressing to mosaic vessels, and eventually leading to endothelium-dependent vessels. However, many phenomena unique to VM channel formation remain to be elucidated, such as the origin of erythrocytes before VM vessels connect with endothelium-dependent vessels.

RESULTS

In adults, erythroid cells are generally believed to be generated from hematopoietic stem cells in the bone marrow. In contrast, embryonic tissue obtains oxygen through formation of blood islands, which are largely composed of embryonic hemoglobin with a higher affinity with oxygen, in the absence of mature erythrocytes. Recent data from our laboratory suggest that embryonic blood-forming mechanisms also exist in cancer tissue, particularly when these tissues are under environmental stress such as hypoxia. We review the evidence from induced pluripotent stem cells in vitro and in vivo to support this previously underappreciated cell functionality in normal and cancer cells, including the ability to generate erythroid cells. We will also summarize the current understanding of tumor angiogenesis, VM, and our recent work on polyploid giant cancer cells, with emphasis on their ability to generate erythroid cells and their association with tumor growth under hypoxia.

CONCLUSION

An alternative embryonic pathway to obtain oxygen in cancer cells exists, particularly when they are under hypoxic conditions.

Clinical significance of hWAPL polymorphisms in the risk of cervical carcinogenesis

To investigate the clinical significance of human wings apart-like (hWAPL) genetic polymorphisms in cervical carcinogenesis. hWAPL polymorphisms and human papillomavirus (HPV) types were examined in 175 cervical smears of exfoliated cervical cell samples using a real-time polymerase chain reaction system. A significant difference was detected in the frequency of the CC genotype between the HPV(+) low-grade squamous intraepithelial lesion (LSIL) and high-grade squamous intraepithelial lesion (HSIL) groups [Odds ratio 0.21, 95% confidence interval (CI) 0.0723-0.61; P = 0.0029]. A significant difference was noted in the frequency of the CC genotype between the high-risk HPV-positive LSIL and HSIL groups (odds ratio 0.2955, 95% CI 0.0893-0.9771; P = 0.0414). The CC genotype of hWAPL gene promoter polymorphism may be associated with cervical carcinogenesis.

No erythropoietin-induced growth is observed in non-small cell lung cancer cells

Lung cancer patients have the highest incidence of anemia among patients with solid tumors. The use of recombinant human erythropoietin (Epo) has consistently been shown to reduce the need for blood transfusions and to increase hemoglobin levels in lung cancer patients with chemotherapy-induced anemia. However, clinical and preclinical studies have prompted concerns that Epo and the presence of its receptor, EpoR, in tumor cells may be responsible for adverse effects and, eventually, death. The question has been raised whether Epo promotes tumor growth and inhibits the death of cancer cells. In this study, we investigated the presence and functionality of EpoR, as well as the implications of Epo upon the proliferation and survival of lung cancer cells. Since the protein expression of both Epo and EpoR is induced by hypoxia, which is frequently present in lung cancer, the cells were treated with Epo under both normoxic and hypoxic conditions (1% O2). By using quantitative (real-time) PCR, western blot analysis, and immunocytochemical staining, three non-small cell lung cancer (NSCLC) cell lines (A427, A549 and NCI-H358) were analyzed for the expression of EpoR and its specific downstream signaling pathways [Janus kinase 2 (Jak2)-signal transducer and activator of transcription 5 (STAT5), phosphatidylinositol-3-kinase (PI3K)-Akt, mitogen-activated protein (MAP) kinase]. The effects of 100 U/ml Epo on cell proliferation and cisplatin-induced apoptosis were assessed. All NSCLC cell lines expressed EpoR mRNA and protein, while these levels differed considerably between the cell lines. We found the constitutive phosphorylation of EpoR and most of its downstream signaling pathways (STAT5, Akt and ERK1/2) independently of Epo administration. While Epo markedly enhanced the proliferation and reduced apoptosis of Epo-dependent UT-7/Epo leukemia cells, it did not affect tumor cell proliferation or the cisplatin-induced apoptosis of NSCLC cells. Thus, this in vitro study suggests that there are no tumor-promoting effects of Epo in the NSCLC cell lines studied, neither under normoxic nor under hypoxic conditions.

Erythropoietin promoted the proliferation of hepatocellular carcinoma through hypoxia induced translocation of its specific receptor

Background

Erythropoietin (EPO) is a hypoxia-inducible stimulator of erythropoiesis. Besides its traditional application in anemia therapy, it offers an effective treatment in the cancer patients, especially those who receive chemotherapy. Several reports indicated that it could promote the tumor cell proliferation through its specific receptor (EPOR). Unfortunately, the role of EPO/EPOR in hepatocellular carcinoma (HCC) progressing is still uncertain.

Methods

Protein in tumor tissue from HCC patients or H22 tumor-bearing mice was detected with immunohistochemistry. Cells were cultured under 1% oxygen to establish hypoxia. RT-PCR and western blotting were used to measure mRNA and protein of EPO/EPOR, respectively. MTT, flow cytometry and PCNA staining were used to detect cell proliferation. Immunofluorescence staining was applied to study the expression and location of cellular EPOR. The EPOR binding studies were performed with ¹²⁵I-EPO radiolabeling assay.

Results

EPO and EPOR protein were up-regulated in HCC tissue of patients and H22-bearing mice. These were positively correlated with hypoxia-inducible factor -1 α and ki-67. Hypoxia up-regulated the expression of EPO and EPOR in HepG2 cells. It also induced the proliferation and increased the percentage of divided cells after 24, 48 and 72 h treatment. These were inhibited in cells pre-treated with 0.5 μg/mL soluble-EPOR. Immunofluorescence staining presented that EPOR was obviously translocated from nucleus to cytoplasm and membrane under hypoxia. EPOR binding activity was also increased after exposure to hypoxia. Recombinant human erythropoietin obviously elevated cell proliferation rate and the percentage of divided under hypoxia but not normoxia, which were also inhibited by soluble-EPOR.

Conclusions

Our result indicated for the first time that EPO promoted the proliferation of HCC cells through hypoxia induced translocation of it specific receptor.

Trial registration TJC20141113, retrospectively registered

Expression level of microRNA-200c is associated with cell morphology in vitro and histological differentiation through regulation of ZEB1/2 and E-cadherin in gastric carcinoma

Scirrhous type gastric cancer is characterized by diffuse infiltration of poorly differentiated adenocarcinoma cells and poor prognosis. Although association of poorly differentiated histology with reduction in E-cadherin expression, as well as association of microRNA (miR)-200c with E-cadherin through regulation of ZEB1/2, has been reported, participation of miR-200c in gastric carcinogenesis is not fully understood. We used 6 cell lines originating from gastric cancers, and investigated levels of miR-200c along with its target mRNAs ZEB1/2 and E-cadherin by qRT-PCR. ZEB1 and E-cadherin protein expression was also assessed via western blotting. Furthermore, we investigated the expression levels of miR-200c by in situ hybridization, along with the expression of ZEB1 and E-cadherin by immunohistochemistry, in 97 gastric adenocarcinoma tissues. Inverse correlation between miR-200c and ZEB1 levels were obtained by qRT-PCR in cell lines (P<0.05). Cell lines with low miR-200c and high ZEB1 exhibited low E-cadherin expression in both qRT-PCR and western blotting, and exhibited spindle-shaped morphology, in contrast to round cell morphology in those cell lines with high miR-200c levels. Inverse correlations were also obtained between miR-200c and ZEB1 as well as between ZEB1 and E-cadherin levels in tissue samples (P<0.001). Cancer tissues with low miR-200c, high ZEB1, and low E-cadherin expression were associated with poorly differentiated histology, in contrast to tubular form in cancers with high miR-200c expression levels (P<0.001). Our data revealed that downregulation of miR-200c primarily regulated cell morphology by downregulation of E-cadherin through upregulation of ZEB1, leading to poorly differentiated histology in gastric cancer.

Erythropoietin and co.: intrinsic structure and functional disorder

Erythropoietin (Epo) is a heavily glycosylated protein, with its main function being related to erythropoiesis, where it controls red blood cell production via interaction with the Epo receptor (EpoR). It also plays a number of important roles in various hormonal, growth factor, and cytokine pathways. These roles are defined by Epo partners, such as the homodimeric (EpoR)2 receptor, the heterodimeric EpoR/βCR receptor and hypoxia inducing factor (HIF). Although the main structural features of both Epo and EpoR are conserved in vertebrates, the secretion sites of Epo in mammals are different from those in other vertebrates. Both biosynthetic and synthetic analogues of this protein are available on the market. Several side effects, such as pure red cells aplaisa, increase the rate of cancer-related death in patients treated with recombinant Epo. The multifunctionality of Epo and the ability of this protein to serve as a hormone, a cytokine, and a growth factor suggest the presence of functional disorder, which is a typical "structural" feature of moonlighting proteins. The goal of this article is to evaluate the roles of intrinsic disorder in the functions of Epo and its primary interactors, EpoR, βCR, and HIF-1α.

Nomogram for risk prediction of malignant transformation in oral leukoplakia patients using combined biomarkers

OBJECTIVE

Squamous cell carcinomas (SCC) are the most common malignancies in the oral mucosa; these carcinomas have been preceded by potentially malignant oral disorders (PMODs), mostly oral leukoplakia (OL). No specific biomarker has been widely accepted for predicting the risk of malignant transformation of PMODs. The aim of this study was to develop an accurate prediction model for the malignant transformation of OL using clinical variables and candidate biomarkers.

MATERIALS AND METHODS

To achieve this goal, 10 candidate biomarkers that had previously been reported as useful molecules were investigated: P53, Ki-67, P16, β-catenin, c-jun, c-met, insulin like growth factor II mRNA-binding protein (IMP-3), cyclooxygenase (COX-2), podoplanin (PDPN) and carbonic anhydrase 9 (CA9). For this study, malignant transformed (n=22, median interval of malignant conversion: 3.3years) and untransformed (n=138) OL specimens with median follow-up period of 11.3years (range: 4.6-23.2years) were immunohistochemically stained.

RESULTS

Using univariate Cox regression analysis, all biomarkers were proven to be significant for predicting malignant transformation in OL. To reach the highest prediction accuracy, the repeated simulation was performed, revealing that the combination of P53 and CA9 with the clinical factors including age and degree of dysplasia achieved the highest prediction accuracy. We constructed a nomogram with the identified prognostic factors for predicting the 5-, 10-, and 15-year progression free survival of OL.

CONCLUSIONS

The proposed nomogram may be useful for the accurate and individual prediction of the transformation to SCC in OL patients and may help clinicians offer appropriate treatments and follow up.

Reduced cancer mortality at high altitude: The role of glucose, lipids, iron and physical activity

Residency at high altitude (HA) demands adaptation to challenging environmental conditions with hypobaric hypoxia being the most important one. Epidemiological and experimental data suggest that chronic exposure to HA reduces cancer mortality and lowers prevalence of metabolic disorders like diabetes and obesity implying that adaption to HA modifies a broad spectrum of physiological, metabolic and cellular programs with a generally beneficial outcome for humans. However, the complexity of multiple, potentially tumor-suppressive pathways at HA impedes the understanding of mechanisms leading to reduced cancer mortality. Many adaptive processes at HA are tightly interconnected and thus it cannot be ruled out that the entirety or at least some of the HA-related alterations act in concert to reduce cancer mortality. In this review we discuss tumor formation as a concept of competition between healthy and cancer cells with improved fitness - and therefore higher competitiveness - of healthy cells at high altitude. We discuss HA-related changes in glucose, lipid and iron metabolism that may have an impact on tumorigenesis. Additionally, we discuss two parameters with a strong impact on tumorigenesis, namely drug metabolism and physical activity, to underpin their potential contribution to HA-dependent reduced cancer mortality. Future studies are needed to unravel why cancer mortality is reduced at HA and how this knowledge might be used to prevent and to treat cancer patients.

Erythropoietin promoted the proliferation of hepatocellular carcinoma through hypoxia induced translocation of its specific receptor

BACKGROUND

Erythropoietin (EPO) is a hypoxia-inducible stimulator of erythropoiesis. Besides its traditional application in anemia therapy, it offers an effective treatment in the cancer patients, especially those who receive chemotherapy. Several reports indicated that it could promote the tumor cell proliferation through its specific receptor (EPOR). Unfortunately, the role of EPO/EPOR in hepatocellular carcinoma (HCC) progressing is still uncertain.

METHODS

Protein in tumor tissue from HCC patients or H22 tumor-bearing mice was detected with immunohistochemistry. Cells were cultured under 1% oxygen to establish hypoxia. RT-PCR and western blotting were used to measure mRNA and protein of EPO/EPOR, respectively. MTT, flow cytometry and PCNA staining were used to detect cell proliferation. Immunofluorescence staining was applied to study the expression and location of cellular EPOR. The EPOR binding studies were performed with ¹²⁵I-EPO radiolabeling assay.

RESULTS

EPO and EPOR protein were up-regulated in HCC tissue of patients and H22-bearing mice. These were positively correlated with hypoxia-inducible factor -1 α and ki-67. Hypoxia up-regulated the expression of EPO and EPOR in HepG2 cells. It also induced the proliferation and increased the percentage of divided cells after 24, 48 and 72 h treatment. These were inhibited in cells pre-treated with 0.5 μg/mL soluble-EPOR. Immunofluorescence staining presented that EPOR was obviously translocated from nucleus to cytoplasm and membrane under hypoxia. EPOR binding activity was also increased after exposure to hypoxia. Recombinant human erythropoietin obviously elevated cell proliferation rate and the percentage of divided under hypoxia but not normoxia, which were also inhibited by soluble-EPOR.

CONCLUSIONS

Our result indicated for the first time that EPO promoted the proliferation of HCC cells through hypoxia induced translocation of it specific receptor. Trial registration TJC20141113, retrospectively registered.

Siah-1 is associated with expression of hypoxia-inducible factor-1α in oral squamous cell carcinoma

OBJECTIVE

Hypoxia-inducible factor-1 (HIF-1) is a heterodimeric basic helix-loop-helix transcription factor composed of the HIF-1α and HIF-1β subunits. HIF-1 is a central regulator of responses to hypoxia; it enhances metastasis-related factors such as matrix metalloproteinases and vascular endothelial growth factor (VEGF). We have reported critical roles for HIF-1α in tumor microenvironments, and oncogenic properties of HIF-1α have been suggested in malignancies. Seven in absentia homologue (Siah) appeared to upregulate HIF-1 production, which prompted us to investigate the Siah association with HIF-1α expression in oral squamous cell carcinoma (OSCC).

METHODS

Samples from fifty-five patients with OSCC were evaluated by immunohistochemistry for the protein expressions of Siah-1 and -2, HIF-1α, and VEGF. The expression levels of each protein and clinicopathological data were statistically analyzed.

RESULTS

Siah-1 and, Siah-2, HIF-1α, and VEGF were immunolocalized on the cell membranes and cytoplasm of the tumor cells. The expression of Siah-1 showed a linear dependence on the expression of HIF-1α (r=0.627, p<0.001). In 17 cases of the large tumor size category (T3 and 4), the mean Siah-1 expression score was significantly higher than in 41 cases of the small tumor size category (T1 and 2; p=0.001). In addition, in 16 cases of the lymph node metastasis-positive category (N1-3), the mean Siah-1 expression score was significantly higher than that in 42 cases of the lymph node metastasis-negative category (N0, p=0.001).

CONCLUSION

These results suggested that the expressions of Siah-1 and HIF-1α were clearly correlated in OSCC. Moreover, Siah-1 appears to be correlated with clinicopathological data, particularly tumor size.

Resistance to Recombinant Human Erythropoietin Therapy in a Rat Model of Chronic Kidney Disease Associated Anemia

This study aimed to elucidate the mechanisms explaining the persistence of anemia and resistance to recombinant human erythropoietin (rHuEPO) therapy in a rat model of chronic kidney disease (CKD)-associated anemia with formation of anti-rHuEPO antibodies. The remnant kidney rat model of CKD induced by 5/6 nephrectomy was used to test a long-term (nine weeks) high dose of rHuEPO (200 UI/kg bw/week) treatment. Hematological and biochemical parameters were evaluated as well as serum and tissue (kidney, liver and/or duodenum) protein and/or gene expression of mediators of erythropoiesis, iron metabolism and tissue hypoxia, inflammation, and fibrosis. Long-term treatment with a high rHuEPO dose is associated with development of resistance to therapy as a result of antibodies formation. In this condition, serum EPO levels are not deficient and iron availability is recovered by increased duodenal absorption. However, erythropoiesis is not stimulated, and the resistance to endogenous EPO effect and to rHuEPO therapy results from the development of a hypoxic, inflammatory and fibrotic milieu in the kidney tissue. This study provides new insights that could be important to ameliorate the current therapeutic strategies used to treat patients with CKD-associated anemia, in particular those that become resistant to rHuEPO therapy.

Clinicopathological characteristics of gynecological cancer associated with hypoxia-inducible factor 1α expression: a meta-analysis including 6,612 subjects

BACKGROUND

Gynecological cancer is characterized by tumor hypoxia. However, the role of hypoxia-inducible factor 1α (HIF-1α) in gynecological cancer remains unclear.

METHOD

Electronic databases including Cochrane Library, PUBMED, Web of Knowledge and clinical trial registries were searched from inception through October 2014 for published, case-control studies assessing the association between HIF-1α and the clinicopathological characteristics of gynecological cancer. We pooled results from 59 studies using fixed or random-effects models and present results as odds ratios (ORs) following the PRISMA guidelines.

RESULTS

Our meta-analysis, which included 6,612 women, demonstrated that the expression of HIF-1α was associated with the clinicopathological characteristics of gynecological cancer. The expression of HIF-1α in cancer or borderline tissue was significantly higher than that in normal tissue (cancer vs. normal: odds ratio (OR) =9.59, 95% confidence interval (CI): 5.97, 15.39, p<0.00001; borderline vs. normal: OR=4.13, 95% (CI): 2.43, 7.02, p<0.00001; cancer vs. borderline: OR=2.70, 95% (CI): 1.69, 4.31, p<0.0001). The expression of HIF-1α in III-IV stage or lymph node metastasis was significantly higher than that in I-II stage or that without lymph node metastasis, respectively (OR=2.66, 95% (CI): 1.87,3.79, p<0.00001; OR= 3.98, 95% (CI): 2.10,12.89, p<0.0001). HIF-1α was associated with histological grade of cancer (Grade 3 vs. Grade 1: OR=3.77, 95% (CI): 2.76,5.16, p<0.00001; Grade 3 vs. Grade 2: OR=1.62, 95% (CI): 1.20,2.19, p=0.002; Grade 2 vs. Grade 1: OR=2.34, 95% (CI): 1.82,3.00, p<0.00001),5-years disease free survival (DFS) rates (OR=2.93, 95% (CI):1.43,6.01, p=0.001) and 5-years overall survival (OS) rates (OR=5.53, 95% (CI): 2.48,12.31, p<0.0001).

CONCLUSION

HIF-1α is associated with the malignant degree, FIGO stage, histological grade, lymph node metastasis, 5-years survival rate and recurrence rate of gynecological cancer. It may play an important role in clinical treatment and prognostic evaluation.

Prognostic value of tumor suppressors in osteosarcoma before and after neoadjuvant chemotherapy

Background

Primary bone cancers are among the deadliest cancer types in adolescents, with osteosarcomas being the most prevalent form. Osteosarcomas are commonly treated with multi-drug neoadjuvant chemotherapy and therapy success as well as patient survival is affected by the presence of tumor suppressors. In order to assess the prognostic value of tumor-suppressive biomarkers, primary osteosarcoma tissues were analyzed prior to and after neoadjuvant chemotherapy.

Methods

We constructed a tissue microarray from high grade osteosarcoma samples, consisting of 48 chemotherapy naïve biopsies (BXs) and 47 tumor resections (RXs) after neoadjuvant chemotherapy. We performed immunohistochemical stainings of P53, P16, maspin, PTEN, BMI1 and Ki67, characterized the subcellular localization and related staining outcome with chemotherapy response and overall survival. Binary logistic regression analysis was used to analyze chemotherapy response and Kaplan-Meier-analysis as well as the Cox proportional hazards model was applied for analysis of patient survival.

Results

No significant associations between biomarker expression in BXs and patient survival or chemotherapy response were detected. In univariate analysis, positive immunohistochemistry of P53 (P = 0.008) and P16 (P16; P = 0.033) in RXs was significantly associated with poor survival prognosis. In addition, presence of P16 in RXs was associated with poor survival in multivariate regression analysis (P = 0.003; HR = 0.067) while absence of P16 was associated with good chemotherapy response (P = 0.004; OR = 74.076). Presence of PTEN on tumor RXs was significantly associated with an improved survival prognosis (P = 0.022).

Conclusions

Positive immunohistochemistry (IHC) of P16 and P53 in RXs was indicative for poor overall patient survival whereas positive IHC of PTEN was prognostic for good overall patient survival. In addition, we found that P16 might be a marker of osteosarcoma chemotherapy resistance. Therefore, our study supports the use of tumor RXs to assess the prognostic value of biomarkers.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-015-1397-4) contains supplementary material, which is available to authorized users.

Erythropoietin Receptor Antagonist Suppressed Ectopic Hemoglobin Synthesis in Xenografts of HeLa Cells to Promote Their Destruction

The aim of this study is to explore a cause-oriented therapy for patients with uterine cervical cancer that expresses erythropoietin (Epo) and its receptor (EpoR). Epo, by binding to EpoR, stimulates the proliferation and differentiation of erythroid progenitor cells into hemoglobin-containing red blood cells. In this study, we report that the HeLa cells in the xenografts expressed ε, γ, and α globins as well as myoglobin (Mb) to produce tetrameric α2ε2 and α2γ2 and monomeric Mb, most of which were significantly suppressed with an EpoR antagonist EMP9. Western blotting revealed that the EMP9 treatment inhibited the AKT-pAKT, MAPKs-pMAPKs, and STAT5-pSTAT5 signaling pathways. Moreover, the treatment induced apoptosis and suppression of the growth and inhibited the survival through disruption of the harmonized hemoprotein syntheses in the tumor cells concomitant with destruction of vascular nets in the xenografts. Furthermore, macrophages and natural killer (NK) cells with intense HIF-1α expression recruited significantly more in the degenerating foci of the xenografts. These findings were associated with the enhanced expressions of nNOS in the tumor cells and iNOS in macrophages and NK cells in the tumor sites. The treated tumor cells exhibited a substantial number of perforations on the cell surface, which indicates that the tumors were damaged by both the nNOS-induced nitric oxide (NO) production in the tumor cells as well as the iNOS-induced NO production in the innate immune cells. Taken together, these data suggest that HeLa cells constitutively acquire ε, γ and Mb synthetic capacity for their survival. Therefore, EMP9 treatment might be a cause-oriented and effective therapy for patients with squamous cell carcinoma of the uterine cervix.

Iron-hepcidin dysmetabolism, anemia and renal hypoxia, inflammation and fibrosis in the remnant kidney rat model

Anemia is a common complication of chronic kidney disease (CKD) that develops early and its severity increases as renal function declines. It is mainly due to a reduced production of erythropoietin (EPO) by the kidneys; however, there are evidences that iron metabolism disturbances increase as CKD progresses. Our aim was to study the mechanisms underlying the development of anemia of CKD, as well as renal damage, in the remnant kidney rat model of CKD induced by 5/6 nephrectomy. This model of CKD presented a sustained degree of renal dysfunction, with mild and advanced glomerular and tubulointerstitial lesions. Anemia developed 3 weeks after nephrectomy and persisted throughout the protocol. The remnant kidney was still able to produce EPO and the liver showed an increased EPO gene expression. In spite of the increased EPO blood levels, anemia persisted and was linked to low serum iron and transferrin levels, while serum interleukin (IL)-6 and high sensitivity C-reactive protein (hs-CRP) levels showed the absence of systemic inflammation. The increased expression of duodenal ferroportin favours iron absorption; however, serum iron is reduced which might be due to iron leakage through advanced kidney lesions, as showed by tubular iron accumulation. Our data suggest that the persistence of anemia may result from disturbances in iron metabolism and by an altered activity/function of EPO as a result of kidney cell damage and a local inflammatory milieu, as showed by the increased gene expression of different inflammatory proteins in the remnant kidney. In addition, this anemia and the associated kidney hypoxia favour the development of fibrosis, angiogenesis and inflammation that may underlie a resistance to EPO stimuli and reduced iron availability. These findings might contribute to open new windows to identify putative therapeutic targets for this condition, as well as for recombinant human EPO (rHuEPO) resistance, which occurs in a considerable percentage of CKD patients.

Erythropoietin and erythropoietin receptor in hepatocellular carcinoma: correlation with vasculogenic mimicry and poor prognosis

To evaluate erythropoietin (Epo) and erythropoietin receptor (EpoR) expression, its relationship with vasculogenic mimicry (VM) and its prognostic value in human hepatocellular carcinoma (HCC), we examined Epo/EpoR expression and VM formation using immunohistochemistry and CD31/PAS (periodic acid-Schiff) double staining on 92 HCC specimens. The correlation between Epo/EpoR expression and VM formation was analyzed using two-tailed Chi-square test and Spearman correlation analysis. Survival curves were generated using Kaplan-Meier method. Multivariate analysis was performed using Cox regression model to assess the prognostic values. Results showed positive correlation between Epo/EpoR expression and VM formation (P < 0.05). Patients with Epo or EpoR expression exhibited poorer overall survival (OS) than Epo-negative or EpoR-negative patients (P < 0.05). Epo-positive/VM-positive and EpoR-positive/VM-positive patients had the worst OS (P < 0.05). In multivariate survival analysis, age, Epo and EpoR were independent prognostic factors related to OS. These results will provide evidence for further research on HCC microcirculation patterns and also will provide new possible targets for HCC diagnosis and treatment.

Long-term results of radiation therapy oncology group 9903: a randomized phase 3 trial to assess the effect of erythropoietin on local-regional control in anemic patients treated with radiation therapy for squamous cell carcinoma of the head and neck

PURPOSE

This paper reports long-term results of RTOG 9903, to determine whether the addition of erythropoietin (EPO) would improve the outcomes of radiation therapy (RT) in mildly to moderately anemic patients with head and neck squamous cell carcinoma (HNSCCa).

METHODS AND MATERIALS

The trial included HNSCCa patients treated with definitive RT. Patients with stage III or IV disease received concomitant chemoradiation therapy or accelerated fractionation. Pretreatment hemoglobin levels were required to be between 9.0 and 13.5 g/dL (12.5 g/dL for females). EPO, 40,000 U, was administered weekly starting 7 to 10 days before RT was initiated in the RT + EPO arm.

RESULTS

A total of 141 of 148 enrolled patients were evaluable. The baseline median hemoglobin level was 12.1 g/dL. In the RT + EPO arm, the mean hemoglobin level at 4 weeks increased by 1.66 g/dL, whereas it decreased by 0.24 g/dL in the RT arm. With a median follow-up of 7.95 years (range: 1.66-10.08 years) for surviving patients and 3.33 years for all patients (range: 0.03-10.08 years), the 5-year estimate of local-regional failure was 46.2% versus 39.4% (P=.42), local-regional progression-free survival was 31.5% versus 37.6% (P=.20), and overall survival was 36.9% versus 38.2% (P=.54) for the RT + EPO and RT arms, respectively. Late toxicity was not different between the 2 arms.

CONCLUSIONS

This long-term analysis confirmed that despite the ability of EPO to raise hemoglobin levels in anemic patients with HNSCCa, it did not improve outcomes when added to RT. The possibility of a detrimental effect of EPO could not be ruled out.

Risk prediction for malignant conversion of oral epithelial dysplasia by hypoxia related protein expression

AIMS

Increased aerobic glycolysis is a unique finding in cancers and hypoxia-related proteins are associated with aerobic glycolysis. Therefore, we aimed to investigate whether hypoxia-related proteins can be predictive markers for malignant conversion of oral premalignant lesions with epithelial dysplasia (OED).

METHODS

Expression of HIF-1α, Glut-1 and CA9 were detected in clinical samples of eight normal oral mucosa, 85 transitional areas of oral squamous cell carcinoma (OSCC) and 28 OED with or without malignant conversion using immunohistochemistry and were also comparatively detected in immortalised human oral keratinocyte (IHOK) and OSCC cell lines under hypoxia using immunoblotting.

RESULTS

Sequential expression of HIF-1α, Glut-1 and CA9 was found both in transitional areas of OSCC and cell lines of IHOK and OSCC under hypoxia, supporting hypoxia-aerobic glycolysis-acidosis axis. Expression of all proteins showed significant association with malignant conversion of OED and CA9 was an independent risk factor of malignant transformation of OED. But the predictability of malignant transformation was improved when all three proteins were applied together.

CONCLUSION

High expression of CA9 was an independent predictive marker of malignant conversion. Moreover, the combined application of these three proteins may be useful to assess the risk of malignant conversion of OED.

Hypoxia promotes the proliferation of cervical carcinoma cells through stimulating the secretion of IL-8

To explore whether hypoxia and interleukin 8 (IL-8) regulate the viability and apoptosis of cervical carcinomas cells and the possible mechanism. We evaluated the expression of hypoxia inducible factor-1α (HIF-1α), IL-8 and its receptors (CXCR1 and CXCR2) in cervical cancer and cervicitis tissues by immunohistochemistry. Then the effects of hypoxia and IL-8 on the viability and apoptosis of HeLa and SiHa cells were detected by the SRB and apoptosis assays. Here we observed that the expression of HIF-1α, IL-8 and CXCR1 in cervical cancer tissues was significantly higher than that in cervicitis tissues. Hypoxic condition stimulated the secretion of IL-8 and the expression of CXCR1 and CXCR2 on HeLa and SiHa cells. Recombinant human IL-8 enhanced the viability and reduced the apoptosis in HeLa and SiHa cells. HeLa and SiHa cells cultured in 1% oxygen showed the increased viability and apoptosis, and the former effect could be partly reversed by anti-human IL-8 neutralizing antibody. This data suggested that IL-8 secreted by cervical carcinomas cells induced by hypoxia can stimulate the viability of cervical carcinomas cells in an autocrine dependent manner, and contribute to the pathogenesis of cervical cancer.

The role of erythropoietin and erythropoietin receptor in malignant laryngeal tumors

Erythropoietin (Epo) is a glycoprotein hormone responsible for erythropoiesis. Its effect is realized by binding erythropoietin receptor (EpoR) expressed on erythroid progenitor cells. Hypoxia is the main stimulus for the secretion of erythropoietin. Anemia is an independent negative prognostic factor for survival in patients with malignant diseases. Synthetic forms of erythropoietin are used in clinical oncology practice to increase the level of hemoglobin. As well as endogenous they can bind to EpoR. Considering the fact that most effects of synthetic Epo are negative, the role of endogenous Epo/EpoR has become an extremely important issue. The authors do not agree on most items related to the effects of exogenous Epo and EpoR in patients with head and neck carcinomas. We are investigating the expression of Epo/EpoR in the tissue of malignant laryngeal carcinoma. Our hypothesis is that less differentiated laryngeal carcinomas will have a higher level of endogenous Epo/EpoR expression. Therefore, in patients with positive Epo/EpoR we expect shorter survival and poorer locoregional disease control. We anticipate that our hypothesis may help to provide the role of endogenous Epo/EpoR in patients with malignant tumors of the larynx. If the assumptions of this study are confirmed, the patients with laryngeal carcinomas whose tumor cells express Epo/EpoR should not be considered for the treatment of anemia with recombinant erythropoietin in any case. We also point out that our research will expand the knowledge of the biology of laryngeal tumor cells and that the results could be utilized as basic knowledge in development of future therapeutic strategies.

Prognosis of patients with locally advanced squamous cell carcinoma of the head and neck. Impact of tumor cell expression of EPO and EPO-R

BACKGROUND AND PURPOSE

This study investigated the prognostic role of tumor cell expression of erythropoietin (EPO) and its receptor (EPO-R) in patients with locally advanced squamous cell carcinoma of the head and neck (SCCHN) treated with surgery plus radiotherapy.

PATIENTS AND METHODS

The impact of EPO, EPO-R, and 11 additional factors on locoregional control (LRC), metastases-free survival (MFS), and overall survival (OS) was retrospectively evaluated in 144 patients. Additional factors were age, gender, performance status, preradiotherapy (pre-RT) hemoglobin levels, tumor site, histologic grade, T category, N category, human papillomavirus (HPV) status, extent of resection, and chemotherapy. Univariate analyses were performed with the Kaplan-Meier method and the log-rank test, multivariate analyses with the Cox proportional hazard model.

RESULTS

On multivariate analysis, improved LRC was significantly associated with no EPO expression (risk ratio [RR] 3.72; 95 % confidence interval [CI] 1.35-15.42; p = 0.008), lower T category (RR 1.60; 95 %CI 1.14-2.32; p = 0.005), and oropharynx or larynx cancer (RR 1.23; 95 %CI 1.02-1.49; p = 0.033). Improved MFS was significantly associated with no EPO expression (RR 5.45; 95 %CI 1.13-97.81; p = 0.031), lower T category (RR 1.66; 95 %CI 1.11-2.65; p = 0.013), lower N category (RR 2.44; 95 %CI 1.04-6.66; p = 0.039), HPV positivity (RR 3.14; 95 %CI not available; p = 0.034), and oropharynx or larynx cancer (RR 1.28; 95 %CI 1.01-1.61; p = 0.041). Improved OS was significantly associated with no EPO expression (RR 4.77; 95 %CI 1.63-20.68; p = 0.003), no EPO-R expression (RR 2.36; 95 %CI 1.22-4.92; p = 0.010), lower T category (RR 1.44; 95 %CI 1.04-2.04; p = 0.027), oropharynx or larynx cancer (RR 1.30; 95 %CI 1.08-1.57; p = 0.007), and pre-RT hemoglobin ≥ 12 g/dl (RR 1.94; 95 %CI 1.03-3.65; p = 0.042).

CONCLUSION

EPO expression of tumor cells was an independent prognostic factor for LRC, MFS, and OS. EPO-R expression was an independent prognostic factor for OS.

The expression level of miR-18b in hepatocellular carcinoma is associated with the grade of malignancy and prognosis

Background

Many studies support the hypothesis that specific microRNA (miRNA) expression in various human cancers including hepatocarcinogenesis is closely associated with diagnosis and prognosis. In hepatocellular carcinoma (HCC), malignancy level is related to the degree of histological differentiation.

Methods

In order to establish a novel biomarker that can determine the degree of malignancy and forecast patient prognosis, we performed a microarray analysis to investigate the miRNA expression profiles in 110 HCC which were comprised of 60 moderately, 30 poorly, and 20 well differentiated HCC.

Results

We found that the expression of 12 miRNAs varied significantly according to the degree of histological differentiation. Particularly, miR-18b expression in poorly differentiated HCC was significantly higher than in well differentiated HCC. Based on miRanda and Targetscan target search algorithms and Argonaute 2 immunoprecipitation study, we noted that miR-18b can control the expression of trinucleotide repeat containing 6B (TNRC6B) as a target gene. Additionally, in two hepatoma cell lines, we found that over-expression of miR-18b or down-regulation of TNRC6B accelerated cell proliferation and loss of cell adhesion ability. Finally, we observed that after surgical resection, HCC patients with high miR-18b expression had a significantly shorter relapse-free period than those with low expression.

Conclusions

miR-18b expression is an important marker of cell proliferation and cell adhesion, and is predictive of clinical outcome. From a clinical point of view, our study emphasizes miR-18b as a diagnostic and prognostic marker for HCC progression.

Adaptor protein complex of FRS2β and CIN85/CD2AP provides a novel mechanism for ErbB2/HER2 protein downregulation

Overexpression of the ErbB2/HER2 receptor tyrosine kinase contributes to tumorigenesis. However, mechanisms regulating ErbB2 protein levels remain largely unclear. Here, we identified novel mechanisms of ErbB2 downregulation. ErbB2 constitutively binds to an adaptor protein FRS2β. We found that FRS2β bound to CD2AP and CIN85, which induces endosomal trafficking that targets lysosomes. FRS2β colocalized with CIN85 in the cytoplasm. Expression of wild type FRS2β but not its CIN85 non-binding mutant, downregulated the ErbB2 protein and inhibited anchorage-independent cell growth. Moreover, the E3 ubiquitin-protein ligase Cbl was contained within a complex of FRS2β and CIN85. Knockdown of both CIN85 and CD2AP or of Cbl, or treatment with lysosomal degradation inhibitors diminished FRS2β downregulation of ErbB2. In addition, knockdown of endogenous FRS2β caused upregulation of ErbB2 in primary neural cells. Finally, immunohistochemical analysis showed that human breast cancer tissues that overexpress ErbB2 expressed low levels of FRS2β. Thus, an FRS2β-CIN85/CD2AP-Cbl axis for downregulation of ErbB2 may regulate ErbB2 protein levels in physiological and pathological settings. Molecular targeting drugs that can increase or stabilize the ErbB2-FRS2β-CIN85/CD2AP-Cbl axis may have promise for the control of ErbB2-overexpressing tumors.

MicroRNA-18a modulates STAT3 activity through negative regulation of PIAS3 during gastric adenocarcinogenesis

Background:

MicroRNA (miRNA, miR)-18a is a member of the miR-17–92 cluster, an important locus that is markedly overexpressed in several cancers and associated with cancer development and progression. However, the mechanism of action of the miR-17–92 cluster and its individual miRNAs are largely unknown.

Methods and Results:

In this study, we investigated the expression of the miR-17–92 cluster by in situ hybridisation (ISH) assay and copy-number analysis in gastric tissue microarray (TMA) specimens. We determined that miR-18a was present at higher levels than the other five miRNAs in the cluster. In addition, we identified Protein Inhibitor of Activated Signal Transducer and Activator of Transcription 3 (PIAS3) as a direct target of miR-18a in gastric cancer. miR-18a level was positively correlated with levels of Survivin, Bcl-xL, and c-Myc, which are downstream transcriptional targets of Signal Transducer and Activator of Transcription 3 (STAT3). STAT3-induced transcription can be negatively regulated by PIAS3; consistent with this, PIAS3 level was negatively correlated with levels of Survivin, Bcl-xL, and c-Myc.

Conclusion:

Our findings indicate that miR-18a acts as an oncogene and plays a role in gastric adenocarcinogenesis, at least in part by negatively regulating PIAS3 and thereby modulating expression of STAT3 target genes.

In vivo angiogenic activity of erythropoietin

The role of erythropoietin (Epo) has been demonstrated in tissues outside the hematopoietic system, including the cardiovascular system, where Epo promotes various effects in endothelial cells. Here, we have demonstrated the angiogenic capacity of recombinant human Epo (rhuEpo) in vivo, by means of the chick embryo chorioallantoic membrane (CAM) assay, a well-established in vivo assay to study angiogenesis and antiangiogenesis.

Long-term and stable correction of uremic anemia by intramuscular injection of plasmids containing hypoxia-regulated system of erythropoietin expression

Relative deficiency in production of glycoprotein hormone erythropoietin (Epo) is a major cause of renal anemia. This study planned to investigate whether the hypoxia-regulated system of Epo expression, constructed by fusing Epo gene to the chimeric phosphoglycerate kinase (PGK) hypoxia response elements (HRE) in combination with cytomegalovirus immediate-early (CMV IE) basal gene promoter and delivered by plasmid intramuscular injection, might provide a long-term physiologically regulated Epo secretion expression to correct the anemia in adenine-induced uremic rats. Plasmid vectors (pHRE-Epo) were synthesized by fusing human Epo cDNA to the HRE/CMV promoter. Hypoxia-inducible activity of this promoter was evaluated first in vitro and then in vivo in healthy and uremic rats (n = 30 per group). The vectors (pCMV-Epo) in which Epo expression was directed by a constitutive CMV gene promoter served as control. ANOVA and Student's t-test were used to analyze between-group differences. A high-level expression of Epo was induced by hypoxia in vitro and in vivo. Though both pHRE-Epo and pCMV-Epo corrected anemia, the hematocrit of the pCMV-Epo-treated rats exceeded the normal (P < 0.05), but that of the pHRE-Epo-treated rats didn't. Hypoxia-regulated system of Epo gene expression constructed by fusing Epo to the HRE/CMV promoter and delivered by plasmid intramuscular injection may provide a long-term and stable Epo expression and secretion in vivo to correct the anemia in adenine-induced uremic rats.

Low-level laser therapy alleviates neuropathic pain and promotes function recovery in rats with chronic constriction injury: possible involvements in hypoxia-inducible factor 1α (HIF-1α)

Nerve inflammation plays an important role in the development and progression of neuropathic pain after chronic constrictive injury (CCI). Recent studies have indicated that hypoxia-inducible factor 1α (HIF-1α) is crucial in inflammation. Low-level laser therapy has been used in treating musculoskeletal pain, but rare data directly support its use for neuropathic pain. We investigated the effects of low-level laser on the accumulation of HIF-1α, tumor necrosis factor-α (TNF-α), and interleukin-1β (IL-1β) in controlling neuropathic pain, as well as on the activation of vascular endothelial growth factor (VEGF) and nerve growth factor (NGF) in promoting functional recovery in a rat CCI model. CCI was induced by placing four loose ligatures around the sciatic nerve of rats. Treatments of low-level laser (660 nm, 9 J/cm(2)) or sham irradiation (0 J/cm(2)) were performed at the CCI sites for 7 consecutive days. The effects of laser in animals with CCI were determined by measuring the mechanical paw withdrawal threshold, as well as the sciatic, tibial, and peroneal function indices. Histopathological and immunoassay analyses were also performed. Low-level laser therapy significantly improved paw withdrawal threshold and the sciatic, tibial, and peroneal functional indices after CCI. The therapy also significantly reduced the overexpressions of HIF-1α, TNF-α, and IL-1β, and increased the amounts of VEGF, NGF, and S100 proteins. In conclusion, a low-level laser could modulate HIF-1α activity. Moreover, it may also be used as a novel and clinically applicable therapeutic approach for the improvement of tissue hypoxia/ischemia and inflammation in nerve entrapment neuropathy, as well as for the promotion of nerve regeneration. These findings might lead to a sufficient morphological and functional recovery of the peripheral nerve.

The effect of erythropoietin on normal and neoplastic cells

Erythropoietin (Epo) is an essential hormone that binds and activates the Epo receptor (EpoR) resident on the surface of erythroid progenitor cells, thereby promoting erythropoiesis. Recombinant human erythropoietin has been used successfully for over 20 years to treat anemia in millions of patients. In addition to erythropoiesis, Epo has also been reported to have other effects, such as tissue protection and promotion of tumor cell growth or survival. This became of significant concern in 2003, when some clinical trials in cancer patients reported increased tumor progression and worse survival outcomes in patients treated with erythropoiesis-stimulating agents (ESAs). One of the potential mechanisms proffered to explain the observed safety issues was that functional EpoR was expressed in tumors and/or endothelial cells, and that ESAs directly stimulated tumor growth and/or antagonized tumor ablative therapies. Since then, numerous groups have performed further research evaluating this potential mechanism with conflicting data and conclusions. Here, we review the biology of endogenous Epo and EpoR expression and function in erythropoiesis, and evaluate the evidence pertaining to the expression of EpoR on normal nonhematopoietic and tumor cells.

Systemic VHL gene functions and the VHL disease

The von Hippel-Lindau tumor suppressor gene (VHL) is best known as an E3 ubiquitin ligase that negatively regulates the hypoxia inducible factor (HIF). VHL mutations are the genetic defects underlying several human diseases including polycythemia, familial VHL tumor syndrome and sporadic renal cell carcinoma. VHL mutations can lead to cell-autonomous phenotypes in the tumor cells. However, non-tumor cell-autonomous functions of VHL have also been noted. VHL tumor-derived cytokines can promote inflammation and induce mobilization of endothelial progenitor cells. Up-regulation of HIF caused by VHL loss-of-function mutants, including heterozygotes, has been shown to increase the activities of hematopoietic stem cells, endothelial cells and myeloid cells. As such, systemic functions of VHL likely play important roles in the development of VHL disease.

Recombinant human erythropoietin promotes the acquisition of a malignant phenotype in head and neck squamous cell carcinoma cell lines in vitro

Background

Recent studies indicate an increase in tumor progression and recurrence in head and neck squamous cell carcinomas (HNSCC) of cancer patients taking recombinant human erythropoietin (rhEpo) for anemia. This study was undertaken to investigate the potential role of rhEpo in invasion, proliferation, and cisplatin-induced cell death in HNSCC cell lines.

Methods

The following experiments were performed with two HNSCC cell lines, UMSCC-10B and UMSCC-22B. Presence of EpoR in both cell lines was determined by western blot and quantitative PCR. Colorimetric MTS assays and clonogenic assays were used to study the effect of rhEpo at pharmacologically relevant doses on cell proliferation. Matrigel invasion assays were performed in order to determine effects of exogenous rhEpo on invasive abilities. Clonogenic assays were also used to study potential cytoprotective effects of rhEpo against cisplatin. Immunoblotting was done to analyze the effect of rhEpo on Akt phosphorylation. Finally, MTS and TUNEL assays were performed to test our hypothesis that Akt activation by PI3K was involved in rhEpo-mediated cisplatin resistance.

Results

HNSCC cell lines were shown to express Epo receptor (EpoR). RhEpo increased invasion 1.8-fold in UMSCC-10B and 2.6-fold in UMSCC-22B compared to control. RhEpo at 10 U/ml increased cell proliferation by 41% and 53% in UMSCC-10B and UMSCC-22B, respectively, and colony formation by 1.5-fold and 1.8-fold. UMSCC-10B treated with cisplatin and exposed to rhEpo at 1 and 10 U/ml resulted in a 1.7-fold and 3.0-fold increase in colony number compared to control, respectively. UMSCC-22B treated with cisplatin and rhEpo at 1 or 10 U/ml resulted in ~2.5-fold increase in colony number. A TUNEL assay demonstrated a 30.5% and 76.5% increase in survival in UMSCC-10B and UMSCC-22B cells, respectively, in cisplatin and rhEpo-treated cells compared to cisplatin alone. MTS assay showed similar cytoprotective effects. Western blot revealed increased phosphorylation of Akt upon exposure of HNSCC cell lines to rhEpo. MTS assay and TUNEL analyses implicate Akt as a likely contributor to regulation of rhEpo-mediated cytoprotection.

Conclusions

The results demonstrate that, in HNSCC cells expressing functional EpoR, rhEpo promotes invasion, cell proliferation, and induces resistance to cisplatin, which may contribute to tumor progression.

Promises and pitfalls in erythopoietin-mediated tissue protection: are nonerythropoietic derivatives a way forward?

The essential biological role of erythropoietin (EPO) in maintaining erythrocyte mass has been well understood for many years. Although EPO is required for the maturation of red cells, it also has strong procoagulant effects on the vascular endothelium and platelets, which limit erythrocyte losses after hemorrhage. Like other members of the type 1 cytokine superfamily, EPO has multiple biological activities. For the past 10 years, multiple investigators have shown that EPO acts as a locally produced antagonist of proinflammatory cytokines that are generated by the innate immune response in response to infection, trauma, or metabolic stress. Specifically, EPO inhibits apoptosis of cells surrounding a locus of injury, reduces the influx of inflammatory cells, and recruits tissue-specific stem cells and endothelial progenitor cells. Available evidence suggests that these multiple, nonerythropoietic effects of EPO are mediated by a tissue protective receptor (TPR) that is distinct from the homodimeric receptor responsible for erythropoiesis. Notably, activation of the TPR requires a higher concentration of EPO than is needed for maximal erythropoiesis. Unfortunately, these higher concentrations of EPO also stimulate hematopoietic and procoagulant pathways, which can cause adverse effects and, therefore, potentially limit the clinical use of EPO for tissue protection. To circumvent these problems, the EPO molecule has been successfully modified in a variety of ways to interact only with the TPR. Early clinical experience has shown that these compounds appear to be safe, and proof of concept trials are ready to begin.

miR-92 is a key oncogenic component of the miR-17-92 cluster in colon cancer

MicroRNAs (miRNAs) belong to a class of endogenously expressed non-coding small RNAs that function primarily as gene regulators. Growing evidence suggests that miRNAs play a significant role in tumor development, making them potential biomarkers for cancer diagnosis and prognosis. The miR-17-92 cluster has emerged as an important locus, being highly overexpressed in several cancers in association with cancer development and progression. The miR-17-92 miRNA cluster generates a single polycistronic primary transcript that yields six mature miRNAs: miR-17, miR-18a, miR-19a, miR-20a, miR-19b, and miR-92a. In colon cancer development, the pathophysiologic roles of these transcripts and their targets are largely unknown. In the present study, we performed copy number analyses of the six miRNAs transcribed from the miR-17-92 cluster in colon tumor tissues. We determined that miR-92a was transcribed at higher levels than the other five miRNAs in both adenomas and carcinoma. In addition, miR-92a directly targeted the anti-apoptotic molecule BCL-2-interacting mediator of cell death (BIM) in colon cancer tissues. An anti-miR-92a antagomir induced apoptosis of colon cancer-derived cell lines. These data indicate that miR-92a plays a pivotal role in the development of colorectal carcinoma.

Prognostic significance of erythropoietin and erythropoietin receptor in gastric adenocarcinoma

AIM: To investigate the expression of Erythropoietin (Epo) and its receptor (EpoR) in gastric adenocarcinoma (GAC) and the correlation with angiogenesis and clinicopathological features.

METHODS: The expressions of Epo, EpoR and vascular endothelial growth factor (VEGF), as well as microvessel density were evaluated in 172 GAC biopsies by immunohistochemical staining. The correlations between these parameters and patient’s clinicopathological features were analyzed statistically.

RESULTS: The proportion of Epo and EpoR alterations in GAC was higher than that in adjacent normal mucosa (P = 0.035 and 0.030). Epo high-expression was associated with EpoR high-expression, Lauren type, extensive lymph node metastasis and advanced stage of GAC (P = 0.018, 0.018, 0.004 and 0), while EpoR expression was linked with older age, World Health Organization type, extensive lymph node metastasis and advanced stage (P = 0.001, 0.013, 0.008 and 0.001). VEGF high expression was significantly correlated with EpoR low-expression, Lauren type, extensive lymph node metastasis and advanced stage (P = 0.001, 0.001, 0.001 and 0.007). The expression of Epo or EpoR was associated with microvessel density (P = 0.004 and 0.046). On multivariate analysis, only lymph node metastasis, abnormal Epo expression and tumor nodes metastases stage were independently associated with survival. In addition, a strong association with the immunohistochemical expression of EpoR and the angiogenic protein, VEGF, was noted.

CONCLUSION: Increased expression of Epo and EpoR may play a significant role in the carcinogenesis, angiogenesis and progression of GAC. Epo may be an independent prognostic factor.

Chronic CSE treatment induces the growth of normal oral keratinocytes via PDK2 upregulation, increased glycolysis and HIF1α stabilization

BACKGROUND

Exposure to cigarette smoke is a major risk factor for head and neck squamous cell carcinoma (HNSCC). We have previously established a chronic cigarette smoke extract (CSE)-treated human oral normal keratinocyte model, demonstrating an elevated frequency of mitochondrial mutations in CSE treated cells. Using this model we further characterized the mechanism by which chronic CSE treatment induces increased cellular proliferation.

METHODOLOGY/PRINCIPAL FINDINGS

We demonstrate that chronic CSE treatment upregulates PDK2 expression, decreases PDH activity and thereby increases the glycolytic metabolites pyruvate and lactate. We also found that the chronic CSE treatment enhanced HIF1α accumulation through increased pyruvate and lactate production in a manner selectively reversible by ascorbate. Use of a HIF1α small molecule inhibitor blocked the growth induced by chronic CSE treatment in OKF6 cells. Furthermore, chronic CSE treatment was found to increase ROS (reactive oxygen species) production, and application of the ROS scavengers N-acetylcysteine abrogated the expression of PDK2 and HIF1α. Notably, treatment with dichloroacetate, a PDK2 inhibitor, also decreased the HIF1α expression as well as cell proliferation in chronic CSE treated OKF6 cells.

CONCLUSIONS/SIGNIFICANCE

Our findings suggest that chronic CSE treatment contribute to cell growth via increased ROS production through mitochondrial mutations, upregulation of PDK2, attenuating PDH activity thereby increasing glycolytic metabolites, resulting in HIF1α stabilization. This study suggests a role for chronic tobacco exposure in the development of aerobic glycolysis and normoxic HIFα activation as a part of HNSCC initiation. These data may provide insights into development of chemopreventive strategies for smoking related cancers.

Association between pharmaceutical support and basic science research on erythropoiesis-stimulating agents

BACKGROUND

To our knowledge, no prior research has evaluated the association between pharmaceutical industry funding and basic science research results. When erythropoiesis-stimulating agents (ESAs) were licensed to treat chemotherapy-associated anemia, basic science concerns related to potential cancer stimulation were raised. We evaluated associations between pharmaceutical industry support and reported findings evaluating ESA effects on cancer cells.

METHODS

Articles identified in MEDLINE and EMBASE databases (1988-2008) investigating basic science findings related to ESA administration in the solid tumor setting were reviewed. Outcomes included information on erythropoietin receptors (EpoRs), Epo-induced signaling events, cellular function, and qualitative conclusions. Information on study funding (academic investigators with no reported funding from ESA manufacturers [64 studies], academic investigators with grant funding from ESA manufacturers [7 studies], and investigators employed by the ESA manufacturers [3 studies]) was evaluated. Some studies did not include information on each outcome.

RESULTS

Investigators without funding from ESA manufacturers were more likely than academic investigators with such funding or investigators employed by ESA manufacturers to identify EpoRs on solid tumor cells (100%, 60%, and 67%, respectively; P = .009), Epo-induced signaling events (94%, 0%, and 0%, respectively; P = .001), or changes in cellular function (57%, 0%, and 0%, respectively; P = .007) and to conclude that ESAs had potentially harmful effects on cancer cells (57%, 0%, and 0%, respectively; P = .008).

CONCLUSIONS

Researchers who do not have pharmaceutical industry support are more likely than those with pharmaceutical support to identify detrimental in vitro effects of ESAs. The potential for conflicts of interest to affect basic science research should be considered.

Erythropoietin is involved in angiogenesis in human primary melanoma

In this study, the extent of angiogenesis, evaluated as microvascular volume density, immunoreactivity of tumour cells to erythropoietin (Epo) and of endothelial cells to Epo receptor (EpoR) have been correlated in human primary melanoma specimens. Results showed that Epo/EpoR expression correlate with angiogenesis and tumour thickness. These findings suggest that Epo is secreted by tumour cells and it affects vascular endothelial cells via its receptor and promotes angiogenesis in a paracrine manner, playing an important role in melanoma angiogenesis.

Epo is involved in angiogenesis in human glioma

In this study, the extent of angiogenesis, evaluated as microvascular density, and the immunoreactivity of tumor cells to erythropoietin (Epo) and of endothelial cells to Epo receptor (EpoR) have been correlated in human glioma specimens, and the effect of anti-Epo antibody on glioma-induced angiogenesis in vivo in the chick embryo chorioallantoic membrane (CAM) has been investigated. Results show that: (1) Epo/EpoR expression correlates with angiogenesis, (2) in the CAM assay, tumor bioptic specimens induce a strong angiogenic response, comparable to that induced by VEGF, and (3) an anti-Epo antibody co-administered with tumor bioptic specimens significantly inhibits the angiogenic response. These findings suggest the presence of a loop in the Epo/EpoR system, i.e. Epo is secreted by glioma tumor cells and it affects glioma vascular endothelial cells via its receptor and promotes angiogenesis in a paracrine manner. Moreover, as demonstrated by in vivo experiments, Epo is responsible for the strong angiogenic response induced by human glioma bioptic specimens, because an anti-Epo antibody is able to significantly inhibit this response.