Erythropoietin and erythropoietin receptor coexpression is associated with poor survival in stage I non-small cell lung cancer

Erythropoietin receptor is a risk factor for prognosis: A potential biomarker in lung adenocarcinoma

Lung cancer has the highest mortality rate of all cancers, and LUAD's survival rate is particularly poor. Erythropoietin receptor (EPOR) can be detected in lung adenocarcinoma (LUAD), however, the expression levels and prognostic value of EPOR in LUAD are still unclear. In our study, clinicopathological data of 92 LUAD patients between January 2008 and June 2016, multiple bioinformatics databases and immunohistochemistry were used to explore the EPOR expression, the mutant genes affecting EPOR expression, and the correlation of EPOR expression with oxidative stress - related genes, prognosis, immune microenvironment. All statistical analyses were performed in the R version 4.1.1. The study found that EPOR expression might be down-regulated at the mRNA levels and significantly up-regulated at the protein levels in LUAD, which indicates that the mRNA and protein levels of EPOR are inconsistent. The muTarget showed that the expression of EPOR was significantly different between the mutant group and the wild group of 15 genes, including DDX60L and C1orf168. Importantly, we found that EPOR was associated with VEGF and HIF family members, and had significant positive correlation with oxidative stress - related genes such as CCS, EPX and TXNRD2. This suggests that EPOR may be involved in the regulation of oxidative stress. The Kaplan-Meier Plotter and PrognoScan databases consistently concluded that EPOR was associated with prognosis in LUAD patients. Our clinicopathological data showed that high EPOR expression was associated with poorer overall survival (29.5 vs 46 months) and had a good predictive ability for 4-year and 5-year survival probability. EPOR is expected to be a potential new prognostic marker for LUAD.

Erythropoietin receptor regulates tumor mitochondrial biogenesis through iNOS and pAKT

Erythropoietin receptor (EPOR) is widely expressed in healthy and malignant tissues. In certain malignancies, EPOR stimulates tumor growth. In healthy tissues, EPOR controls processes other than erythropoiesis, including mitochondrial metabolism. We hypothesized that EPOR also controls the mitochondrial metabolism in cancer cells. To test this hypothesis, we generated EPOR-knockdown cancer cells to grow tumor xenografts in mice and analyzed tumor cellular respiration via high-resolution respirometry. Furthermore, we analyzed cellular respiratory control, mitochondrial content, and regulators of mitochondrial biogenesis in vivo and in vitro in different cancer cell lines. Our results show that EPOR controls tumor growth and mitochondrial biogenesis in tumors by controlling the levels of both, pAKT and inducible NO synthase (iNOS). Furthermore, we observed that the expression of EPOR is associated with the expression of the mitochondrial marker VDAC1 in tissue arrays of lung cancer patients, suggesting that EPOR indeed helps to regulate mitochondrial biogenesis in tumors of cancer patients. Thus, our data imply that EPOR not only stimulates tumor growth but also regulates tumor metabolism and is a target for direct intervention against progression.

An Aging-Related Gene Signature-Based Model for Risk Stratification and Prognosis Prediction in Lung Adenocarcinoma

Aging is an inevitable time-dependent process associated with a gradual decline in many physiological functions. Importantly, some studies have supported that aging may be involved in the development of lung adenocarcinoma (LUAD). However, no studies have described an aging-related gene (ARG)-based prognosis signature for LUAD. Accordingly, in this study, we analyzed ARG expression data from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO). After LASSO and Cox regression analyses, a six ARG-based signature (APOC3, EPOR, H2AFX, MXD1, PLCG2, and YWHAZ) was constructed using TCGA dataset that significantly stratified cases into high- and low-risk groups in terms of overall survival (OS). Cox regression analysis indicated that the ARG signature was an independent prognostic factor in LUAD. A nomogram based on the ARG signature and clinicopathological factors was developed in TCGA cohort and validated in the GEO dataset. Moreover, to visualize the prediction results, we established a web-based calculator yurong.shinyapps.io/ARGs_LUAD/. Calibration plots showed good consistency between the prediction of the nomogram and actual observations. Receiver operating characteristic curve and decision curve analyses indicated that the ARG nomogram had better OS prediction and clinical net benefit than the staging system. Taken together, these results established a genetic signature for LUAD based on ARGs, which may promote individualized treatment and provide promising novel molecular markers for immunotherapy.

Erythropoietin promoter polymorphism is associated with treatment efficacy and severe hematologic toxicity for platinum-based chemotherapy

Background: Erythropoietin (EPO) plays a substantial role in cancer development and probably affects clinical outcomes. A functional polymorphism (rs1617640, G > T) in the promoter region of the EPO increases protein expression. This study investigated the association of EPO rs1617640 with treatment efficacy and severe toxicity in non-small cell lung cancer (NSCLC) patients undergoing platinum-based regimens.Methods: 437 Chinese NSCLC patients treated with platinum-based chemotherapy were recruited. Association between EPO rs1617640 and clinical outcomes was calculated by multivariable logistic regression.Results: The TT genotype of EPO rs1617640 was significantly correlated with a higher response rate to platinum-based treatment than the other genotypes (OR, 0.507; 95% CI: 0.305-0.842; P = 0.009), particularly in elderly patients (>55 years), male gender, smokers, IV stage, cisplatin-based chemotherapies, and platinum-gemcitabine regimen subgroups. As for toxicity, EPO rs1617640 TT genotype demonstrated poorer tolerance to grade 3-4 hematologic toxicity (OR, 1.783; 95% CI: 1.098-2.898; P = 0.019), particularly in subgroups of elderly patients (>55 years), male gender, smokers, IIIA+IIIB stage, and cisplatin-based chemotherapies.Conclusion: Our results demonstrated the role of EPO rs1617640 as a possible predictive marker of treatment efficacy and severe toxicity for platinum-based chemotherapy.

Anemia management in cancer patients with chronic kidney disease

Cancer and kidney disease are linked by causality and comorbidities. Observational data show an increased risk of malignancy as renal function declines. Erythropoietin stimulating agents (ESAs), which are the cornerstone therapy for anemia patients with chronic kidney disease and cancer, are associated with increased risks for cancer, cancer-related mortality, progression of disease, and thromboembolic events. This article examines the recently published guidelines for ESA use in cancer patients from the American Society of Clinical Oncology and American Society of Hematology and attempts to contextualize them to the care of patients with coexistent CKD, cancer, and anemia.

Blood serum proteins as biomarkers for prediction of survival, locoregional control and distant metastasis rate in radiotherapy and radio-chemotherapy for non-small cell lung cancer

BACKGROUND

Several studies have documented that blood biomarkers can improve basic prognostic models in radiotherapy and radio-chemotherapy for non-small cell lung cancer. The current study evaluated the prognostic impact of six markers focusing on their utility in homogenous subsets, compared to the significance in a large heterogeneous group.

METHODS

Blood samples of 337 patients who were referred for curative or palliative external beam thoracic radiotherapy for non-small cell lung cancer were collected. The concentration of osteopontin (OPN), vascular endothelial growth factor (VEGF), erythropoetin (EPO), high mobility group box 1 protein (HMGB1), insulin-like growth factor 1 (IGF-1) and platelet-derived growth factor (PDGF) in serum were measured by ELISA assay and the prognostic potential was assessed using univariable and multivariable survival models.

RESULTS

Multivariable analysis revealed that out of several variables studied six dichotomized features: namely: cigarette smoking, lack of chemotherapy, palliative doses of radiotherapy, high OPN concentration, advanced T stage and high VEGF concentration had a highly significant (p < 0.005) and independent influence on overall survival in the group of 337 patients. In a subset of patients treated with curative radio-chemotherapy or radiotherapy (N = 148) tumor pathology, EPO concentration and VEGF concentration, significantly and independently influenced overall survival. In a subset of patients with squamous cell cancer (N = 206) OPN had a highly significant impact on overall survival. In contrast, in a subset of patients with nonsquamous histology (N = 131) only VEGF had a significant influence on survival.

CONCLUSIONS

Blood serum proteins appear to be clinically useful prognosticators of overall survival in radio-chemotherapy and radiotherapy for non-small cell lung cancer. In unselected heterogeneous groups, dichotomized concentrations of OPN and VEGF emerged among the strongest independent prognosticators of overall survival. VEGF and EPO concentration (dichotomized) were found to be independent prognostic factors among the patients treated with curative doses of radiotherapy. The utility of OPN as a prognostic marker appeared restricted to the patients with squamous histology.

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.

Local blockage of self-sustainable erythropoietin signaling suppresses tumor progression in non-small cell lung cancer

Functional significance of co-expressed erythropoietin (EPO) and its receptor (EPOR) in non-small cell lung cancer (NSCLC) had been under debate. In this study, co-overexpression of EPO/EPOR was confirmed to be positively associated with poor survival in NSCLC. The serum EPO in 14 of 35 enrolled NSCLC patients were found elevated significantly and decreased to normal level after tumor resection. With primary tumor cell culture and patient-derived tumor xenograft (PDX) mouse model, the EPO secretion from the tumors of these 14 patients was verified. Then, we proved the patient derived serum EPO was functionally active and had growth promotion effect in EPO/EPOR overexpressed but not in EPO/EPOR under-expressed NSCLC cells. We also illustrated EPO promoted NSCLC cell proliferation through an EPOR/Jak2/Stat5a/cyclinD1 pathway. In xenograft mouse model, we proved local application of EPO neutralizing antibody and short hairpin RNA (shRNA) against EPOR effectively inhibited the growth of EPO/EPOR overexpressed NSCLC cells and prolonged survivals of the mice. Finally, EPO/EPOR/Jak2/Stat5a/cyclinD1 signaling was found to be a mediator of hypoxia induced growth in EPO/EPOR overexpressed NSCLC. Our results illustrated a subgroup of NSCLC adapt to hypoxia through self-sustainable EPO/EPOR signaling and suggest local blockage of EPO/EPOR as potential therapeutic method in this distinct NSCLC population.

Identification of Cell Type-Specific Differences in Erythropoietin Receptor Signaling in Primary Erythroid and Lung Cancer Cells

Lung cancer, with its most prevalent form non-small-cell lung carcinoma (NSCLC), is one of the leading causes of cancer-related deaths worldwide, and is commonly treated with chemotherapeutic drugs such as cisplatin. Lung cancer patients frequently suffer from chemotherapy-induced anemia, which can be treated with erythropoietin (EPO). However, studies have indicated that EPO not only promotes erythropoiesis in hematopoietic cells, but may also enhance survival of NSCLC cells. Here, we verified that the NSCLC cell line H838 expresses functional erythropoietin receptors (EPOR) and that treatment with EPO reduces cisplatin-induced apoptosis. To pinpoint differences in EPO-induced survival signaling in erythroid progenitor cells (CFU-E, colony forming unit-erythroid) and H838 cells, we combined mathematical modeling with a method for feature selection, the L₁ regularization. Utilizing an example model and simulated data, we demonstrated that this approach enables the accurate identification and quantification of cell type-specific parameters. We applied our strategy to quantitative time-resolved data of EPO-induced JAK/STAT signaling generated by quantitative immunoblotting, mass spectrometry and quantitative real-time PCR (qRT-PCR) in CFU-E and H838 cells as well as H838 cells overexpressing human EPOR (H838-HA-hEPOR). The established parsimonious mathematical model was able to simultaneously describe the data sets of CFU-E, H838 and H838-HA-hEPOR cells. Seven cell type-specific parameters were identified that included for example parameters for nuclear translocation of STAT5 and target gene induction. Cell type-specific differences in target gene induction were experimentally validated by qRT-PCR experiments. The systematic identification of pathway differences and sensitivities of EPOR signaling in CFU-E and H838 cells revealed potential targets for intervention to selectively inhibit EPO-induced signaling in the tumor cells but leave the responses in erythroid progenitor cells unaffected. Thus, the proposed modeling strategy can be employed as a general procedure to identify cell type-specific parameters and to recommend treatment strategies for the selective targeting of specific cell types.

A major challenge in the development of therapeutic interventions is the selective inhibition of a signal transduction pathway in one cell type such as a cancer cell leaving the other cell type such as a healthy cell as unaffected as possible. Here, we propose a new approach that combines mathematical modeling based on quantitative experimental data with statistical methods. We demonstrate based on simulated data that our approach can determine which parameters are the same and which parameters differ in two exemplary cell types. We compare a lung cancer cell line to the precursor cells of red blood cells. We show that the same signal transduction network induced by erythropoietin (EPO), a hormone that is frequently employed to treat anemia in cancer patients, regulates survival of both cell types. Based on our experimental data in combination with our computational approach, we identify seven cell type-specific differences in this signaling pathway. Our strategy allows predicting therapeutic targets that could be inhibited to interfere with survival of lung cancer cells while leaving production of red blood cells unaffected.

Progress in detecting cell-surface protein receptors: the erythropoietin receptor example

Testing for the presence of specific cell-surface receptors (such as EGFR or HER2) on tumor cells is an integral part of cancer care in terms of treatment decisions and prognosis. Understanding the strengths and limitations of these tests is important because inaccurate results may occur if procedures designed to prevent false-negative or false-positive outcomes are not employed. This review discusses tests commonly used to identify and characterize cell-surface receptors, such as the erythropoietin receptor (EpoR). First, a summary is provided on the biology of the Epo/EpoR system, describing how EpoR is expressed on erythrocytic progenitors and precursors in the bone marrow where it mediates red blood cell production in response to Epo. Second, studies are described that investigated whether erythropoiesis-stimulating agents could stimulate tumor progression in cancer patients and whether EpoR is expressed and functional on tumor cells or on endothelial cells. The methods used in these studies included immunohistochemistry, Northern blotting, Western blotting, and binding assays. This review summarizes the strengths and limitations of these methods. Critically analyzing data from tests for cell-surface receptors such as EpoR requires understanding the techniques utilized and demonstrating that results are consistent with current knowledge about receptor biology.

Expression and functional significance of the erythropoietin receptor in hepatocellular carcinoma

BACKGROUND

Erythropoietin, through its specific receptor (EpoR), may induce responses in a variety of non-haematopoietic tissues including malignant cells. The purpose of this study was to examine the expression of EpoR in hepatocellular carcinoma (HCC) and to correlate the levels of EpoR expression with the clinicopathological properties of HCC and tumour recurrence.

METHODS

The study included 134 patients who underwent curative hepatectomy for hepatitis B virus (HBV)-related primary HCC. The clinical, laboratory and pathological data from these patients were retrospectively collected. The expression of EpoR mRNA and protein were evaluated by reverse transcription-polymerase chain reaction (RT-PCR) and Western blot analysis, respectively.

RESULTS

Expression of EpoR mRNA in the cirrhotic liver was positively correlated with tumour cell differentiation and 1-year disease-free survival (74.8% in the high expression group versus 46.9% in the low expression group; P = 0.001), as it was for EpoR mRNA expression in HCC (64.4% in the high expression group versus 52.7% in the low expression group; P = 0.044). Tumour recurrence showed stronger dependence on the expression of EpoR protein in non-malignant cirrhotic livers than in HCC.

CONCLUSION

In HBV-related HCC, the levels of EpoR mRNA and protein in non-tumour cirrhotic livers were positively correlated with tumour cell differentiation, which is a favourable predictor of disease-specific survival.

Erythropoietin receptor expression is a potential prognostic factor in human lung adenocarcinoma

Recombinant human erythropoietins (rHuEPOs) are used to treat cancer-related anemia. Recent preclinical studies and clinical trials, however, have raised concerns about the potential tumor-promoting effects of these drugs. Because the clinical significance of erythropoietin receptor (EPOR) signaling in human non-small cell lung cancer (NSCLC) also remains controversial, our aim was to study whether EPO treatment modifies tumor growth and if EPOR expression has an impact on the clinical behavior of this malignancy. A total of 43 patients with stage III–IV adenocarcinoma (ADC) and complete clinicopathological data were included. EPOR expression in human ADC samples and cell lines was measured by quantitative real-time polymerase chain reaction. Effects of exogenous rHuEPOα were studied on human lung ADC cell lines in vitro. In vivo growth of human ADC xenografts treated with rHuEPOα with or without chemotherapy was also assessed. In vivo tumor and endothelial cell (EC) proliferation was determined by 5-bromo-2’-deoxy-uridine (BrdU) incorporation and immunofluorescent labeling. Although EPOR mRNA was expressed in all of the three investigated ADC cell lines, rHuEPOα treatment (either alone or in combination with gemcitabine) did not alter ADC cell proliferation in vitro. However, rHuEPOα significantly decreased tumor cell proliferation and growth of human H1975 lung ADC xenografts. At the same time, rHuEPOα treatment of H1975 tumors resulted in accelerated tumor endothelial cell proliferation. Moreover, in patients with advanced stage lung ADC, high intratumoral EPOR mRNA levels were associated with significantly increased overall survival. This study reveals high EPOR level as a potential novel positive prognostic marker in human lung ADC.

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.

Impact of increased erythropoietin receptor expression and elevated serum erythropoietin levels on clinicopathological features and prognosis in renal cell carcinoma

Erythropoietin (EPO) expression and EPO receptor (EpoR) expression have been demonstrated in various malignant tumors. EPO-EpoR signaling can activate several downstream signal transduction pathways that enhance tumor aggressiveness. The present study was undertaken to evaluate the impact of overexpression of EpoR and elevated serum EPO (sEPO) levels on the clinicopathological features and prognosis of patients with renal cell carcinoma (RCC). EpoR expression was evaluated immunohistochemically in 56 patients. Tumors with a staining intensity greater than that of surrounding proximal tubules were defined as tumors with high EpoR expression. The association between EpoR expression levels and various clinicopathological factors was analyzed. sEPO levels were determined in 138 patients and its correlation to clinicopathological factors was also analyzed, and EpoR expression was determined in surgical specimens removed from 47 of those 138 patients. Patients with high EpoR expression and patients with sEPO elevation had clinicopathological features less favorable than those of other patients. Tumors demonstrating high EpoR expression had a significantly higher number of Ki-67-positive cells compared to those with low EpoR expression. Tumor assemblies in microvessels demonstrated high EpoR expression. Patients whose tumors demonstrated high EpoR expression and those with sEPO elevation had a significantly lower survival rate compared to other patients, and patients with both high EpoR expression and sEPO elevation had an extremely poor prognosis. Microvascular invasion was an independent factor associated with sEPO elevation, suggesting that EPO-EpoR signaling might be important in RCC metastasis. EPO-EpoR signaling may be involved in tumor growth and progression in RCC and the combination of EpoR expression and sEPO levels may effectively predict clinical outcome.

PDGF-BB modulates hematopoiesis and tumor angiogenesis by inducing erythropoietin production in stromal cells

The platelet-derived growth factor (PDGF) signaling system contributes to tumor angiogenesis and vascular remodeling. Here we show in mouse tumor models that PDGF-BB induces erythropoietin (EPO) mRNA and protein expression by targeting stromal and perivascular cells that express PDGF receptor-β (PDGFR-β). Tumor-derived PDGF-BB promoted tumor growth, angiogenesis and extramedullary hematopoiesis at least in part through modulation of EPO expression. Moreover, adenoviral delivery of PDGF-BB to tumor-free mice increased both EPO production and erythropoiesis, as well as protecting from irradiation-induced anemia. At the molecular level, we show that the PDGF-BB-PDGFR-bβ signaling system activates the EPO promoter, acting in part through transcriptional regulation by the transcription factor Atf3, possibly through its association with two additional transcription factors, c-Jun and Sp1. Our findings suggest that PDGF-BB-induced EPO promotes tumor growth through two mechanisms: first, paracrine stimulation of tumor angiogenesis by direct induction of endothelial cell proliferation, migration, sprouting and tube formation, and second, endocrine stimulation of extramedullary hematopoiesis leading to increased oxygen perfusion and protection against tumor-associated anemia.

Erythropoietin promotes the growth of pituitary adenomas by enhancing angiogenesis

rhEPO is frequently used in clinical practice to treat anemia. However, recently rhEPO has been reported to accelerate tumor growth, progression and metastasis. Many pituitary adenoma patients, particularly those with macroprolactinomas, tend to have anemia and may need rhEPO therapy. To date, whether rhEPO has deleterious effects on pituitary adenomas has not been defined. Here we demonstrated for the first time that human pituitary adenomas are EPOR negative tumors and rhEPO accelerated the tumor growth of MMQ pituitary adenoma xenografts via enhancement of angiogenesis in vivo, whereas rhEPO displayed no direct effect on MMQ cells in vitro. Our mechanistic study showed that rhEPO administration increased phosphorylation of JAK2, STAT3 and VEGF expression in human umbilical vein endothelial cells (HUVECs) in vitro and in MMQ cell xenografts in vivo. Furthermore, VEGF inhibitor attenuated rhEPO induced angiogenesis and delayed tumor growth in MMQ pituitary adenoma xenografts in vivo. JAK2 inhibitor AG490 attenuated EPO induced HUVECs proliferation, phosphorylation of JAK2, STAT3 and VEGF upregulation in vitro and inhibited EPO induced vessel formation in Chicken chorioallantoic membrane (CAM) angiogenesis model in vivo. These results suggest that rhEPO administration may promote the growth of pituitary adenomas by enhancing angiogenesis through EPO-JAK2-STAT3-VEGF signaling pathway. rhEPO should be used with caution in anemia patients bearing pituitary adenoma due to its potential deleterious effects.

Targeting the erythropoietin receptor on glioma cells reduces tumour growth

Hypoxia has been shown to be one of the major events involved in EPO expression. Accordingly, EPO might be expressed by cerebral neoplastic cells, especially in glioblastoma, known to be highly hypoxic tumours. The expression of EPOR has been described in glioma cells. However, data from the literature remain descriptive and controversial. On the basis of an endogenous source of EPO in the brain, we have focused on a potential role of EPOR in brain tumour growth. In the present study, with complementary approaches to target EPO/EPOR signalling, we demonstrate the presence of a functional EPO/EPOR system on glioma cells leading to the activation of the ERK pathway. This EPO/EPOR system is involved in glioma cell proliferation in vitro. In vivo, we show that the down-regulation of EPOR expression on glioma cells reduces tumour growth and enhances animal survival. Our results support the hypothesis that EPOR signalling in tumour cells is involved in the control of glioma growth.

Sequential Dose-Dense Doxorubicin and Ifosfamide in Advanced Soft-Tissue Sarcoma Patients in an Out-Patient-Basis Schedule

Aims. This phase II study explored activity/safety of front-line dose-dense chemotherapy in high-grade STS (soft tissue sarcoma) patients and tested ezrin as prognostic factor. Patients and Methods. The protocol consisted of three cycles of doxorubicin (DOXO) 30 mg/m² on days 1–3 every 2 weeks, followed by three cycles of ifosfamide (IFO) 2.5 g/m² two hours a day on days 1–5 every 3 weeks, with GCSF support. Ezrin was assessed immunohistochemically. Results. Twenty patients, 13 metastatic and 7 locally advanced, were enrolled. Median age was 39 years (25–60). Median dose intensities were 42 mg/m²/week and 3.6 g/m²/week for DOXO and IFO, respectively. Grade 3/4 toxicities occurred in 18 patients. Response rate was 15% (3 of 20) by RECIST. Patients younger than 45 years with locally advanced disease and synovial histology presented longer survival. A trend towards longer survival was observed among ezrin-positive patients. Conclusions. This dose-dense schedule should not be routinely used due to its high frequency of toxic events; however, a sequential strategy with DOXO and IFO may benefit selected patients and should be further explored with lower doses. The role of ezrin as a prognostic marker should be confirmed in a larger group of patients.

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.

Prognostic impact of erythropoietin expression and erythropoietin receptor expression on locoregional control and survival of patients irradiated for stage II/III non-small-cell lung cancer

PURPOSE

Prognostic factors can guide the physician in selecting the optimal treatment for an individual patient. This study investigates the prognostic value of erythropoietin (EPO) and EPO receptor (EPO-R) expression of tumor cells for locoregional control and survival in non-small-cell lung cancer (NSCLC) patients.

METHODS AND MATERIALS

Fourteen factors were investigated in 62 patients irradiated for stage II/III NSCLC, as follows: age, gender, Karnofsky performance score (KPS), histology, grading, TNM/American Joint Committee on Cancer (AJCC) stage, surgery, chemotherapy, pack years (average number of packages of cigarettes smoked per day multiplied by the number of years smoked), smoking during radiotherapy, hemoglobin levels during radiotherapy, EPO expression, and EPO-R expression. Additionally, patients with tumors expressing both EPO and EPO-R were compared to those expressing either EPO or EPO-R and to those expressing neither EPO nor EPO-R.

RESULTS

On univariate analysis, improved locoregional control was associated with AJCC stage II cancer (p < 0.048), surgery (p < 0.042), no smoking during radiotherapy (p = 0.024), and no EPO expression (p = 0.001). A trend was observed for a KPS of >70 (p = 0.08), an N stage of 0 to 1 (p = 0.07), and no EPO-R expression (p = 0.10). On multivariate analysis, AJCC stage II and no EPO expression remained significant. No smoking during radiotherapy was almost significant. On univariate analysis, improved survival was associated with N stage 0 to 1 (p = 0.009), surgery (p = 0.039), hemoglobin levels of ≥12 g/d (p = 0.016), and no EPO expression (p = 0.001). On multivariate analysis, N stage 0 to 1 and no EPO expression maintained significance. Hemoglobin levels of ≥12 g/d were almost significant. On subgroup analyses, patients with tumors expressing both EPO and EPO-R had worse outcomes than those expressing either EPO or EPO-R and those expressing neither EPO nor RPO-R.

CONCLUSIONS

EPO expression of tumor cells was an independent prognostic factor for locoregional control and survival in patients irradiated for NSCLC. EPO-R expression showed a trend. Patients with tumors expressing both EPO and EPO-R have an unfavorable prognosis.

The role of erythropoietin and its receptor in growth, survival and therapeutic response of human tumor cells From clinic to bench - a critical review

Recombinant human erythropoietin (rhEPO) has been used clinically to alleviate cancer- and chemotherapy-related anemia. However, recent clinical trials have reported that rhEPO also may adversely impact disease progression and survival. The expression of functional EPO receptors (EPOR) has been demonstrated in many human cancer cells where, at least in vitro, rhEPO can stimulate cell growth and survival and may induce resistance to selected therapies. Responses to rhEPO measured by alterations in tumor cell growth or survival, activation of signaling pathways or modulation of sensitivity to anticancer agents are variable. Both methodological and inherent biological issues underlie the differential cell responses, including reported difficulties in EPOR protein detection, potential involvement of EPOR isoforms or of cytoplasmic EPOR, possible differential structure and/or binding affinities of hematopoietic versus non-hematopoietic cell EPOR, possible aberrant regulation of EPOR activity, and a functional EPO/EPOR autocrine/paracrine loop. The modulation by rhEPO of tumor cell response to anticancer agents is coincident with modulation of multiple signaling pathways, BCL-2 family proteins, caspases and NFkB. The molecular interplay of pro-survival and pro-death signals, triggered by EPO and/or by anticancer agents, is multifactorial and tightly coordinated. Expression microarray analysis may prove critical for deciphering this potentially novel network and its broad spectrum of genes and proteins.

Hypoxia-inducible factor 1 alpha in oral squamous cell carcinoma and its relation to prognosis

The aim of this study was to investigate the correlation between the expression of hypoxia-inducible factor 1 alpha (HIF-1 alpha) and proliferative activity in tumor cells, lymph node metastasis, as well as prognosis in patients with oral squamous cell carcinoma (OSCC). Fifty-seven biopsy specimens of OSCC were investigated for the expression of HIF-1 alpha and proliferating cell nuclear antigen (PCNA) by immunohistochemistry. None of the patients had received any prior treatments. The percentage of HIF-1 alpha immunopositive area (PHIA) was calculated using computer-assisted image analysis for quantitative assessment of HIF-1 alpha expression. The PCNA labeling index (LI) was evaluated as a proliferation marker. We found that the mean PHIA in all stages was 12.1% in the poor prognosis patients, and it was 6.4% in the good prognosis patients. There was a significant difference of PHIA between poor prognosis and good prognosis patients (P=0.0065). Furthermore, the mean PHIA in the patients who had no metastatic lymph nodes was 7.5%, while it was 11.7% in the patients who had metastatic lymph nodes. There was also a significant difference of PHIA between patients who had no metastatic lymph nodes and those who had metastatic lymph nodes (P=0.0487). On the other hand, significant correlation between PHIA and PCNA LI was not observed. These results provide the clinical data indicating that HIF-1 alpha may play an important role in lymph node metastasis and prognosis in patients with OSCC.

Erythropoietin Receptor Signaling Through STAT3 Is Required For Glioma Stem Cell Maintenance

Recombinant erythropoietin (EPO) is a growth factor used in the treatment of chemotherapy-induced anemia, but recent studies suggest that EPO may accelerate cancer growth. Although several cancers express EPO receptors (EPORs), the mechanism by which EPOR promotes tumor growth remains poorly understood. Glioblastomas display a cellular hierarchy of self-renewal and tumor propagation restricted to glioma stem cells (GSCs). We find that GSCs express higher levels of EPOR than matched non-stem glioma cells. Prospective enrichment for EPOR on GSCs increased neurosphere formation, suggesting that EPOR can select for a subset of GSCs with increased self-renewal capacity. Targeting EPOR expression with lentiviral mediated short hairpin RNA (shRNA) reduced GSC growth, survival, and neurosphere formation capacity, defining a crucial role for EPOR in GSC maintenance. We further find that STAT3 is an important mediator of EPOR signals in GSCs. EPOR knockdown attenuated the basal activation of STAT3 present in GSCs, and a small molecule inhibitor of STAT3 reduced GSC growth and survival. EPOR signaling was critical for survival in vivo, as targeting EPOR expression decreased GSC tumorigenic potential. Elevated EPOR expression also associated with poor patient outcome. Thus, EPOR on GSCs promotes tumor growth and may explain the poor survival of cancer patients treated with EPO.

Identification of a sensitive anti-erythropoietin receptor monoclonal antibody allows detection of low levels of EpoR in cells

Erythropoietin (Epo) binds and activates the Epo receptor (EpoR) on the surface of erythroid progenitor cells resulting in formation of erythrocytes. Recently, EpoR was reported to be expressed on non-erythroid cells suggesting a role for Epo outside of erythropoiesis. However those studies employed antibodies with questionable specificity and the significance of the observations are controversial. In order to accurately determine the expression of EpoR proteins in cells, we have generated a panel of novel anti-human EpoR monoclonal antibodies. One of these antibodies (A82) was particularly sensitive and it detected the EpoR protein on intact cells by flow cytometry and by western blot analysis with cell lysates. Both methods were optimized and using them, EpoR protein was detected by western immunoblotting with lysates from fewer than 200 EpoR positive control cells and the positive signals were proportional to EpoR protein expression level with a minimal signal in EpoR negative cells. The proteins detected by western blot analysis using A82 included full-length EpoR ( approximately 59kDa) as well as smaller EpoR fragments derived from the EPOR gene. These results indicate that A82 can be used to examine low level EpoR expression in cells by western and flow cytometry allowing an improved understanding of EpoR expression and metabolism.

Beyond anemia: the clinical impact of the physiologic effects of erythropoietin

Although we have known that oxygen tension affects erythrocyte production since the 19th century, we have only recently begun to understand many subtleties of erythropoietin (EPO) physiology. EPO administration has allowed hundreds of thousands of patients to avoid transfusions. With the beneficial effects so apparent a detailed understanding of the full clinical physiology of this plasma factor seemed less important. However, the unanticipated increase in mortality found in recent randomized studies is prompting a reassessment of this view. We will review what is known about the physiology of this plasma factor that, it is now clear, is more than just an erythrocyte production factor.

Unraveling the Mystery of Erythropoietin-Stimulating Agents in Cancer Promotion

Erythropoietin-stimulating agents (ESA) are approved for use in treating chemotherapy-induced anemia in patients with nonmyeloid malignancies. However, recent clinical trials have shown evidence of inferior overall survival and/or locoregional control of tumors in patients receiving ESAs. Given these concerning data, current studies are focused on elucidating the biological mechanisms by which ESAs may contribute to cancer promotion. Evidence suggests that ESAs activate several signaling pathways that are important in altering tumor behavior and response to treatment. Although further research is needed to more precisely elucidate these mechanisms, caution should be exercised in the use of ESAs beyond their approved indication in cancer patients. [Cancer Res 2008;68(11):4013–7]

[Anemia and lung cancer]

Erythopoietin (EPO) treatment of anemia during cancer has dramatically improved the tolerance of chemotherapy and quality of life of patients at all stages of the disease. Several surveys have demonstrated a high prevalence and a high incidence of anemia in lung cancer patients. The guidelines updates concerning EPO treatment for these patients are described. They take into account the debate concerning the potential harm of these molecules on the neoplastic disease and the possible role of EPO receptors expressed by several tumors, including non small cell lung cancer.