Recombinant human erythropoietin is associated with increased overall survival in patients with multiple myeloma

Erythropoietin enhances Kupffer cell number and activity in the challenged liver

Erythropoietin (EPO) is the main hormone driving mammalian erythropoiesis, with activity mediated via the surface receptor, EPO-R, on erythroid progenitor cells. Recombinant human EPO is currently used clinically for the treatment of anemia in patients with end-stage renal disease, and in certain cancer patients suffering from anemia induced either by the tumor itself or by chemotherapy. EPO-R expression is also detected in non-erythroid cells, including macrophages present in the peritoneum, spleen, and bone marrow (BM). Here we demonstrate that Kupffer cells (KCs) - the liver-resident macrophages - are EPO targets. We show that, in vitro, EPO initiated intracellular signalling and enhanced phagocytosis in a rat KC line (RKC-2) and in sorted KCs. Moreover, continuous EPO administration in mice, resulted in an increased number of KCs, up-regulation of liver EPO-R expression and elevated production of the monocyte chemoattractant CCL2, with corresponding egress of Ly6C^hi monocytes from the BM. In a model of acute acetaminophen-induced liver injury, EPO administration increased the recruitment of Ly6C^hi monocytes and neutrophils to the liver. Taken together, our results reveal a new role for EPO in stimulating KC proliferation and phagocytosis, and in recruiting Ly6C^hi monocytes in response to liver injury.

Erythropoietin (EPO)-receptor signaling induces cell death of primary myeloma cells in vitro

Background

Multiple myeloma is an incurable complex disease characterized by clonal proliferation of malignant plasma cells in a hypoxic bone marrow environment. Hypoxia-dependent erythropoietin (EPO)-receptor (EPOR) signaling is central in various cancers, but the relevance of EPOR signaling in multiple myeloma cells has not yet been thoroughly investigated.

Methods

Myeloma cell lines and malignant plasma cells isolated from bone marrow of myeloma patients were used in this study. Transcript levels were analysed by quantitative PCR and cell surface levels of EPOR in primary cells by flow cytometry. Knockdown of EPOR by short interfering RNA was used to show specific EPOR signaling in the myeloma cell line INA-6. Flow cytometry was used to assess viability in primary cells treated with EPO in the presence and absence of neutralizing anti-EPOR antibodies. Gene expression data for total therapy 2 (TT2), total therapy 3A (TT3A) trials and APEX 039 and 040 were retrieved from NIH GEO omnibus and EBI ArrayExpress.

Results

We show that the EPOR is expressed in myeloma cell lines and in primary myeloma cells both at the mRNA and protein level. Exposure to recombinant human EPO (rhEPO) reduced viability of INA-6 myeloma cell line and of primary myeloma cells. This effect could be partially reversed by neutralizing antibodies against EPOR. In INA-6 cells and primary myeloma cells, janus kinase 2 (JAK-2) and extracellular signal regulated kinase 1 and 2 (ERK-1/2) were phosphorylated by rhEPO treatment. Knockdown of EPOR expression in INA-6 cells reduced rhEPO-induced phospo-JAK-2 and phospho-ERK-1/2. Co-cultures of primary myeloma cells with bone marrow-derived stroma cells did not protect the myeloma cells from rhEPO-induced cell death. In four different clinical trials, survival data linked to gene expression analysis indicated that high levels of EPOR mRNA were associated with better survival.

Conclusions

Our results demonstrate for the first time active EPOR signaling in malignant plasma cells. EPO-mediated EPOR signaling reduced the viability of myeloma cell lines and of malignant primary plasma cells in vitro. Our results encourage further studies to investigate the importance of EPO/EPOR in multiple myeloma progression and treatment.

Trial registration

[Trial registration number for Total Therapy (TT) 2: NCT00083551 and TT3: NCT00081939].

Erythropoietin treatment in murine multiple myeloma: immune gain and bone loss

Multiple myeloma (MM) is a plasma cell malignancy, characterized by osteolytic lesions and monoclonal immunoglobulins. The anemia, accompanying the disease is often treated with recombinant human EPO. Diverse non-erythropoietic effects of EPO have led us to question its combined action on the immune system and bone in the 5T33MM mouse model. EPO administration to MM mice attenuated disease progression as demonstrated by a decrease in serum MM IgG2b, splenic CD138 expressing cells, IL-6 and RORγτ transcripts in bone marrow (BM). IFN-γ transcript levels and macrophages (F4/80⁺CD11b⁺) in the BM both increased ~1.5 fold in the EPO-treated MM mice. In-vitro, EPO stimulated phagocytosis of 5T33MM cells (+30%) by BM-derived macrophages. In contrast, high-resolution microCT analysis of distal femurs revealed EPO-associated bone loss in both healthy and 5T33MM mice. EPO significantly increased expression of the osteoclastogenic nuclear factor-kappa B ligand (RANKL) in healthy mice, but not in MM mice, likely due to antagonizing effects on MM progression. Thus, in MM, EPO may act as a double-edged-sword stimulating immune response, while accelerating bone resorption, possibly via direct action on BM macrophages. This study supports a prudent approach of treating anemia in MM patients, aiming to maintain EPO-associated anti-MM effects, while considering bone damage.

Erythropoietin: the swinging pendulum

Erythropoiesis stimulating agents (ESAs) have been used widely for anemic patients, especially those on dialysis and with cancer. However, reports have suggested shorter survival in erythropoietin (EPO)-treated cancer patients. The purpose of this review is to summarize and evaluate critically the current information about ESA treatment and its possible association with mortality in cancer patients. The pendulum that initially swung in the direction of widespread ESA treatment, and then in the direction of no treatment, is swinging back toward a stable position. This review also provides tools to decide how and when to use ESAs safely, according to accepted guidelines.

Angiogenic activity of classical hematopoietic cytokines

Hematopoiesis is regulated by several cytokines with pleiotropic activity. Several evidences have clearly demonstrated that these molecules, formerly regarded as specific for the hematopoietic system, also affect certain endothelial cell functions and that hematopoietic factors clearly influence angiogenesis. This review article summarizes the most important literature data concerning this inconvertible relationship.

Supportive therapy in multiple myeloma

In this chapter we want to give an overview on various supportive measures, which help to prevent or to fight complications of multiple myeloma, improve patient wellbeing and increase safety of administration of specific anti-myeloma therapy.

Characterization of haematological parameters with bortezomib-melphalan-prednisone versus melphalan-prednisone in newly diagnosed myeloma, with evaluation of long-term outcomes and risk of thromboembolic events with use of erythropoiesis-stimulating agents: analysis of the VISTA trial

Although haematological toxicities, such as anaemia, are common in multiple myeloma (MM), no clear consensus exists on the use and impact of erythropoiesis-stimulating agents (ESA) on outcomes in MM. This analysis characterizes haematological toxicities and associated interventions in the phase III VISTA (Velcade(®) as Initial Standard Therapy in Multiple Myeloma: Assessment with Melphalan and Prednisone) study of bortezomib plus melphalan/prednisone (VMP, n = 344) versus MP (n = 338) in previously untreated MM patients ineligible for high-dose therapy, and evaluates the impact of ESA use or red-blood-cell (RBC) transfusions on outcomes and thromboembolic risk. Incidence of haematological toxicities was similar with VMP and MP; similar rates of interventions and associated complications (e.g. bleeding, febrile neutropenia) were observed. Two hundred thirty three patients received ESA; 204 had RBC transfusions. Frequency of thromboembolic events was low and not affected by ESA use. Median time-to progression (TTP) was similar between ESA/non-ESA [hazard ratio: 1·03 (95% confidence interval 0·76-1·39); P = 0·8478] in both arms (VMP: 19·9/not reached; MP: 15·0/17·5 months). Three-year overall survival (OS) rates were similar between ESA/non-ESA in each arm. Patients receiving RBC transfusions had significantly shorter OS (P < 0·0001) versus non-RBC-transfusion patients. In conclusion, bortezomib did not add to melphalan haematological toxicity. Concomitant ESA use with VMP/MP in previously untreated MM patients did not adversely affect TTP or OS, or increase thromboembolic risk. However, RBC transfusion was associated with significantly shorter survival.

Update on the use of erythropoiesis-stimulating agents (ESAs) for the management of anemia of multiple myeloma and lymphoma

Anemia is a common side-effect of patients with multiple myeloma (MM) and lymphoma. The etiology is complex, but the main cause is the underlying mechanism of anemia of chronic disease, which is characterized among others, by impairment of iron metabolism and consequently iron restricted erythropoiesis (IRE), resulting from the up-regulation of the iron distributing regulator, hepcidin. Erythopoiesis-stimulating agents (ESAs) have been the standard of care since early 90's offering high response rates and improving the quality of life of the patients. However, the role of ESAs in the treatment of cancer-related anemia has been questioned recently, due to the growing evidence which support that ESAs may be associated with increased risk for thrombosis and may have a detrimental impact on patients' survival. Under the light of the recent considerations, the place of ESAs in the management of cancer-related anemia has been reassigned. Regarding the management of anemia in MM or lymphoma, the updated American Society of Clinical Oncology/American Society of Hematology (ASCO/ASH) 2007 clinical practice guidelines on the use of ESAs in cancer-related anemia, recommended that ESAs should be preferably omitted in patients planned to receive chemotherapy and applied in case that anemia does not improve over treatment. The quest for reliable predictors for response to ESAs and for indicators of IRE which plays a major etiological role for the development of anemia of cancer still remains an open issue. In the current review we present an update on ESAs use in anemia of MM and lymphoma.

Biological functions and therapeutic use of erythropoiesis-stimulating agents: perplexities and perspectives

Randomized clinical studies, carried out in patients with haematological malignancies and with solid tumours, have consistently demonstrated that treatment with recombinant human erythropoietin (Epo) increases haemoglobin levels, reduces blood transfusion requirements, and improves the quality of life. In addition, identification of erythropoietin receptor (EpoR) expression on many types of non-erythroid and cancer cells has spurred an interest in the extra-haematological activities of Epo itself and other erythropoiesis-stimulating agents (ESAs). Epo and its derivatives have emerged as major tissue-protective cytokines in ischaemic and degenerative damage of cardiovascular, neurological and renal diseases, while their angiogenetic and immunomodulatory properties indicate that their therapeutic potential may extend well beyond erythropoiesis alone. Both preclinical and clinical data, however, have suggested that they may contribute to tumour progression and prejudice survival when administered to anaemic cancer patients, though the results are equivocal and the assumed mechanisms by which tumour growth could be promoted are not fully understood. While these findings offer new perspectives, they nonetheless demand caution in the employment of ESAs. Further, well-designed experimental and clinical studies are warranted.

Erythropoietin augments survival of glioma cells after radiation and temozolomide

PURPOSE

Despite beneficial effects of irradiation/chemotherapy on survival of glioblastoma (GBM) patients, collateral damage to intact neural tissue leads to "radiochemobrain" and reduced quality of life in survivors. For prophylactic neuroprotection, erythropoietin (EPO) is a promising candidate, provided that concerns regarding potential tumor promoting effects are alleviated.

METHODS AND MATERIALS

Human GBM-derived cell lines U87, G44, G112, and the gliosarcoma-derived line G28 were treated with EPO, with and without combinations of irradiation or temozolomide (TMZ). Responsiveness of glioma cells to EPO was measured by cell migration from spheroids, cell proliferation, and clonogenic survival. Implantation of U87 cells into brains of nude mice, followed 5 days later by EPO treatment (5,000 U/kg intraperitoneal every other day for 2 weeks) should reveal effects of EPO on tumor growth in vivo. Reverse transcriptase-polymerase chain reaction was performed for EPOR, HIF-1alpha, and epidermal growth factor receptor (EGFR)vIII in cell lines and 22 human GBM specimens.

RESULTS

EPO did not modulate basal glioma cell migration and stimulated proliferation in only one of four cell lines. Importantly, EPO did not enhance tumor growth in mouse brains. Preincubation of glioma cells with EPO for 3 h, followed by irradiation and TMZ for another 24 h, resulted in protection against chemoradiation-induced cytotoxicity in three cell lines. Conversely, EPO induced a dose-dependent decrease in survival of G28 gliosarcoma cells. In GBM specimens, expression of HIF-1alpha correlated positively with expression of EPOR and EGFRvIII. EPOR and EGFRvIII expression did not correlate.

CONCLUSIONS

EPO is unlikely to appreciably influence basal glioma growth. However, concomitant use of EPO with irradiation/chemotherapy in GBM patients is not advisable.

Erythropoietin effects on dendritic cells: potential mediators in its function as an immunomodulator?

OBJECTIVE

Modulatory effects of erythropoietin (EPO) on the cellular and humoral compartments of the immune system have been described; however, the mechanism of action by which EPO affects the lymphocyte number and functions has yet to be elucidated. Because no EPO receptors (EPO-R) could be detected on lymphocytes, we searched for cells that might express the EPO-R and thereby mediate these immunomodulatory effects. We thus focused on dendritic cells (DCs), the most potent antigen-presenting and T-cell-priming cells, as possible mediators of the immunomodulatory actions of EPO.

MATERIALS AND METHODS

We examined the in vitro effects of EPO on human DCs. Expression of EPO-R, expression of costimulatory molecules, antigen uptake, secretion of cytokines, and DC maturation were investigated.

RESULTS

We demonstrate that the EPO-R is expressed in human DCs and that EPO directly affects their phenotype and function. When applied in vitro, EPO increased the percentage of peripheral blood DCs and monocyte-derived DCs (MoDCs) expressing the costimulatory molecules CD80 and CD86. EPO treatment of MoDCs was also associated with an increase in surface expression of CD80 and CD86 as well as that of HLA-DR. EPO enhanced MoDC function, as manifested in increased antigen uptake and secretion of interleukin 12. When applied to immature MoDCs, EPO in itself induced their maturation.

CONCLUSION

Our finding that DCs are directly affected by EPO renders them as potential candidates that mediate the immunomodulatory actions of EPO.

Erythropoiesis-stimulating agents are associated with reduced survival in patients with multiple myeloma

The impact of erythropoiesis-stimulating agent (ESA) on cancer patients' survival has recently become a matter of extensive discussion. Studies in solid tumors demonstrated that ESA adversely affects survival. This issue has not been sufficiently studied in patients with multiple myeloma. In this study, which included 323 multiple myeloma patients followed in our Institution between 1988 and 2007, we demonstrated by using a proportional hazards model including multiple covariates (age, LDH, Hb, platelets, serum creatinine, ISS score, beta2 microglobulin, and ESA administration) that ESA administration is associated with reduced survival (hazards ratio: 1.88, 95% CI: 1.28-2.77). Anemia, which is considered a predictor for survival, platelets, serum creatinine, ISS score, and LDH, were not significant, whereas, age and beta2 microglobulin confirmed their predicting value in the multivariate analysis. With a median follow-up of 31 months (range 1-238), the median survival of patients in the ESA group was 31 months (95% CI: 25-37), whereas in the group without ESA administration it was 67 months (95% CI: 55-79) (P < 0.001). The median progression-free survival for patients in the ESA group was 14 months (95% CI: 12-16), and for the group without ESA it was 30 months (95% CI: 24-36) (P < 0.001). These results indicate that ESA may have a detrimental impact on MM patients' outcomes and, thus, in this context, they should be used with rigorous criteria.

Erythropoiesis-stimulating agent hyporesponsiveness

Approximately 5-10% of patients with chronic kidney disease demonstrate hyporesponsiveness to erythropoiesis-stimulating agents (ESA), defined as a continued need for greater than 300 IU/kg per week erythropoietin or 1.5 mug/kg per week darbepoetin administered by the subcutaneous route. Such hyporesponsiveness contributes significantly to morbidity, mortality and health-care economic burden in chronic kidney disease and represents an important diagnostic and management challenge. The commonest causes of ESA resistance are non-compliance, absolute or functional iron deficiency and inflammation. It is widely accepted that maintaining adequate iron stores, ideally by administering iron parenterally, is the most important strategy for reducing the requirements for, and enhancing the efficacy of ESA. There have been recent epidemiologic studies linking parenteral iron therapy to an increased risk of infection and atherosclerosis, although other investigations have refuted this. Inflammatory ESA hyporesponsiveness has been reported to be improved by a number of interventions, including the use of biocompatible membranes, ultrapure dialysate, transplant nephrectomy, ascorbic acid therapy, vitamin E supplementation, statins and oxpentifylline administration. Other variably well-established causes of ESA hyporesponsiveness include inadequate dialysis, hyperparathyroidism, nutrient deficiencies (vitamin B12, folate, vitamin C, carnitine), angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, aluminium overload, antibody-mediated pure red cell aplasia, primary bone marrow disorders, myelosuppressive agents, haemoglobinopathies, haemolysis and hypersplenism. This paper reviews the causes of ESA hyporesponsiveness and the clinical evidence for proposed therapeutic interventions. A practical algorithm for approaching the investigation and management of patients with ESA hyporesponsiveness is also provided.

The impact of tumor expression of erythropoietin receptors and erythropoietin on clinical outcome of esophageal cancer patients treated with chemoradiation

BACKGROUND

To investigate the impact of tumor erythropoietin receptors (Epo-R) and erythropoietin (Epo) expression in 64 patients with Stage III esophageal cancer receiving or not receiving erythropoietin during chemoradiation.

MATERIALS AND METHODS

The impact of tumor Epo-R expression, Epo expression, and 10 additional factors (age, Karnofsky-Performance-Score [KPS], tumor length, T and N stage, histology and grading, hemoglobin during radiotherapy, erythropoietin administration, surgery) on overall survival (OS) and locoregional control (LC) was evaluated.

RESULTS

Improved OS was associated with low (< or =20%) Epo expression (p = 0.049), KPS >80 (p = 0.008), T3 stage (p = 0.010), hemoglobin > or =12 g/dL (p < 0.001), and surgery (p = 0.010). Erythropoietin receptor expression showed a trend (p = 0.09). Locoregional control was associated with T stage (p = 0.005) and hemoglobin (p < 0.001), almost with erythropoietin administration (p = 0.06). On multivariate analyses, OS was associated with KPS (p = 0.045) and hemoglobin (p = 0.032), LC with hemoglobin (p < 0.001). Patients having low expression of both Epo-R and Epo had better OS (p = 0.003) and LC (p = 0.043) than others. Two-year OS was nonsignificantly better (p = 0.25) in patients with low Epo-R expression receiving erythropoietin (50%) than in those with higher Epo-R expression receiving erythropoietin (21%), low Epo-R expression/no erythropoietin administration (29%), or higher Epo-R expression/no erythropoietin administration (18%). Two-year LC rates were, respectively, 65%, 31%, 26%, and 29% (p = 0.20). Results for Epo expression were similar.

CONCLUSIONS

Higher Epo-R expression or Epo expression seemed to be associated with poorer outcomes. Patients with low expression levels receiving erythropoietin seemed to do better than patients with higher expression levels or not receiving erythropoietin. The data need to be confirmed in a larger series of patients.

Activities of erythropoietin on tumors: an immunological perspective

There is a growing interest in the non-erythropoietic, tissue-protective and restorative actions of erythropoietin (EPO). While studies in this field have indicated that EPO can ameliorate chemotherapy-induced peripheral neuropathy and cardiotoxicity, the issue whether EPO can positively or negatively affect cancer patients is a hot one. In this debate, many activities of EPO are being considered, including tissue/neuroprotection, angiogenesis, anti-inflammatory activity, growth promotion, and inhibition of apoptosis. However, few studies have explored the interactions of EPO with the immune system. A study in this issue of the European Journal of Immunology by Katz et al. adds one new piece to the puzzle by showing that EPO can stimulate B cell-mediated immunity.