Brain and cancer: the protective role of erythropoietin

HIF1α: A Novel Biomarker with Potential Prognostic and Immunotherapy in Pan-cancer

Cancer is a catastrophic disease that seriously affects human health. HIF1α plays an important role in cancer initiation, progression, and prognosis. However, little is known about the specific role of HIF1α in pan-cancer. Therefore, we systematically and comprehensively analyzed HIF1α using GEPIA, HPA, GeneMANIA, STRING, SMPDB, cBioPortal, UALCAN, and TISDB databases and also 33 cancer and normal tissues in TCGA downloaded from the Genome Data Commons (GDC) data portal. Data and statistical analysis were performed using R software v4.0.3. Our results found that there were differences in the mRNA expression levels of HIF1α in human pan-cancer and its corresponding normal tissues. The expression level of HIF1α correlated with tumor stage in LIHC and also significantly correlated with prognosis in LIHC, LUSC, STAD, OV, PAAD, PRAD, THCA, LUAD, MESO, and READ. The small molecule pathways involved in HIF1α include succinate signaling, fumarate, and succinate carcinogenesis-related pathways. The highest mutation frequency of the HIF1α gene in pan-cancer was head and neck cancer, and the HIF1α methylation level in most tumors is significantly reduced. HIF1α was not only associated with immune cell infiltration but also with immune checkpoint genes and immune regulators TMB and MSI. There were currently 5 small molecule drugs targeting HIF1α.

Erythropoietin Nanobots: Their Feasibility for the Controlled Release of Erythropoietin and Their Neuroprotective Bioequivalence in Central Nervous System Injury

Background: Erythropoietin (EPO) plays important roles in neuroprotection in central nervous system injury. Due to the limited therapeutic time window and coexistence of hematopoietic/extrahematopoietic receptors displaying heterogenic and phylogenetic differences, fast, targeted delivery agents, such as nanobots, are needed. To confirm the feasibility of EPO-nanobots (ENBs) as therapeutic tools, the authors evaluated controlled EPO release from ENBs and compared the neuroprotective bioequivalence of these substances after preconditioning sonication. Methods: ENBs were manufactured by a nanospray drying technique with preconditioning sonication. SH-SY5Y neuronal cells were cotreated with thapsigargin and either EPO or ENBs before cell viability, EPO receptor activation, and endoplasmic reticulum stress-related pathway deactivation were determined over 24 h. Results: Preconditioning sonication (50–60 kHz) for 1 h increased the cumulative EPO release from the ENBs (84% versus 25% at 24 h). Between EPO and ENBs at 24 h, both neuronal cell viability (both > 65% versus 15% for thapsigargin alone) and the expression of the proapoptotic/apoptotic biomolecular markers JAK2, PDI, PERK, GRP78, ATF6, CHOP, TGF-β, and caspase-3 were nearly the same or similar. Conclusion: ENBs controlled EPO release in vitro after preconditioning sonication, leading to neuroprotection similar to that of EPO at 24 h.

Avoiding Complications in Aneurysm Ligation: Operative Tips and Tricks

Preventing possible complications during brain aneurysm surgery is mandatory to ensure a better outcome for patients. Currently, it is possible to rely on some technologic innovations such as motor evoked potential, endoscope-assisted surgery, dye with indocyanine green, and video angiography capable of supporting the surgeon's work. The innovation process has mainly assisted the endovascular technique compared with surgery. The latter, apart from some new technical expedients, always requires anatomic knowledge and optimal technical preparation. A careful patient selection, adequate surgical exposure, use of microsurgical techniques in expert hands, and meticulous postoperative management represent the key to success for the surgical treatment of cerebral aneurysms.

Targeted Delivery of Erythropoietin Hybridized with Magnetic Nanocarriers for the Treatment of Central Nervous System Injury: A Literature Review

Although the incidence of central nervous system injuries has continued to rise, no promising treatments have been elucidated. Erythropoietin plays an important role in neuroprotection and neuroregeneration as well as in erythropoiesis. Moreover, the current worldwide use of erythropoietin in the treatment of hematologic diseases allows for its ready application in patients with central nervous system injuries. However, erythropoietin has a very short therapeutic time window (within 6–8 hours) after injury, and it has both hematopoietic and nonhematopoietic receptors, which exhibit heterogenic and phylogenetic differences. These differences lead to limited amounts of erythropoietin binding to in situ erythropoietin receptors. The lack of high-quality evidence for clinical use and the promising results of in vitro/in vivo models necessitate fast targeted delivery agents such as nanocarriers. Among current nanocarriers, noncovalent polymer-entrapping or polymer-adsorbing erythropoietin obtained by nanospray drying may be the most promising. With the incorporation of magnetic nanocarriers into an erythropoietin polymer, spatiotemporal external magnetic navigation is another area of great interest for targeted delivery within the therapeutic time window. Intravenous administration is the most readily used route. Manufactured erythropoietin nanocarriers should be clearly characterized using bioengineering analyses of the in vivo size distribution and the quality of entrapment or adsorption. Further preclinical trials are required to increase the therapeutic bioavailability (in vivo biological identity alteration, passage through the lung capillaries or the blood brain barrier, and timely degradation followed by removal of the nanocarriers from the body) and decrease the adverse effects (hematological complications, neurotoxicity, and cytotoxicity), especially of the nanocarrier.

Role of Erythropoietin in Cerebral Glioma: An Innovative Target in Neuro-Oncology

BACKGROUND

Erythropoietin (EPO) is a cytokine primarily involved in the regulation of erythropoiesis. In response to hypoxia-ischemia, hypoxia-inducible factor 1 induces EPO production, which, in turn, inhibits apoptosis of erythroid progenitor cells. By the same mechanism and acting through other signaling pathways, EPO exerts neuroprotective effects. Increased resistance to hypoxia and decreased apoptosis are thought to be important mechanisms for tumor progression, including malignant glioma. Because recent studies have demonstrated that EPO and its receptor (EPOR) are expressed in several tumors and can promote tumor growth, in the present study, we investigated EPO and EPOR expression in human glioma and the effect of EPO administration in a rat model of glioma implantation.

METHODS

Using Western blotting and immunohistochemical analysis, we examined the expression of EPO, EPOR, platelet endothelial cell adhesion molecule, and Ki-67 in human glioma specimens and experimentally induced glioma in rats. In the experimental setting, a daily dose of recombinant human EPO (rHuEPO) or saline solution were administered for 21 days in Fischer rats subjected to 9L cell line implantation.

RESULTS

In both human and animal specimens, we found an increase in EPOR expression as long as the lesion presented with an increasing malignant pattern. A significant direct correlation was found between the expression of EPOR and Ki-67 and EPOR and platelet endothelial cell adhesion molecule in low- and high-grade gliomas. The rats treated with rHuEPO presented with significantly larger tumor spread compared with the saline-treated rats.

CONCLUSIONS

The results of our study have shown that the EPO/EPOR complex might play a significant role in the aggressive behavior of high-grade gliomas. The larger tumor spread in rHuEPO-treated rats suggests a feasible role for EPO in the aggressiveness and progression of malignant glioma.

Combination of intravitreal bevacizumab and erythropoietin versus intravitreal bevacizumab alone for refractory diabetic macular edema: a randomized double-blind clinical trial

PURPOSE

To evaluate the effect of three intravitreal bevacizumab (IVB) injections alone or in combination with intravitreal erythropoietin (EPO) in the treatment of refractory diabetic macular edema (DME).

METHODS

In a randomized double-blind clinical trial, 48 eyes of 34 diabetic patients with refractory DME were enrolled. Eyes were randomly assigned to receive either 3 monthly injections of 0.05 cc (1.25 mg) IVB plus 0.05 cc (1000 unit) EPO or 0.05 cc (1.25 mg) IVB alone. Main outcome was best-corrected visual acuity (BCVA) changes and secondary outcome was central macular thickness (CMT). The patients were followed for 6 months.

RESULTS

Mean BCVA changes up to 4 and 6 months were insignificant in both groups. It changed from 0.72 ± 0.56 logMAR at baseline to 0.74 ± 0.5 (P = 0.85) and 0.71 ± 0.44 (P = 0.40) in the combination group and from 0.48 ± 0.39 logMAR to 0.47 ± 0.35 (P = 0.48) and 0.52 ± 0.33 (P = 0.69) in the IVB alone group, at 4 and 6 months, respectively. The difference of mean BCVA changes between the groups was insignificant at both 4 and 6 months (P = 0.07 and P = 0.36, respectively). Within the group changes of mean CMT were significant only in the combination group at 4 and 6 months, from 518 ± 134 μ at baseline to 472 ± 151 to 475 ± 167 μ, respectively (P = 0.01 and P = 0.05). Corresponding changes were not significant in the IVB alone group. However, the difference between the groups was not significant at all visits (P = 0.51 and P = 0.71, respectively).

CONCLUSIONS

This clinical trial demonstrated that intravitreal erythropoietin had no additional effect to IVB in the treatment of refractory DME in the short term.

TRIAL REGISTRATION

Clinical trials.gov identifier: NCT03821168.

Applications of Liposomal Drug Delivery Systems to Develop Neuroprotective Agents for the Treatment of Ischemic Stroke

Ischemic stroke is one of the leading causes of severe disability and death. In clinical settings, tissue plasminogen activator (t-PA) for thrombolytic therapy is the only globally approved drug for the treatment of ischemic stroke. However, the proportion of patients who receive t-PA therapy is extremely limited due to its narrow therapeutic time window (TTW) and the risk of cerebral hemorrhage. Cerebral ischemia-reperfusion (I/R) injury is also a serious problem for patients' outcomes. Hence, the development of more effective therapies has been desired to prolong the TTW of t-PA and prevent cerebral I/R injury. For delivering drugs into the brain, the blood-brain barrier (BBB) must be overcome since it limits drug penetration into the brain, leading to insufficient therapeutic efficacy. As a distinctive pathology after an ischemic stroke, it was reported that the vascular permeability of the BBB is increased around the ischemic region. We found that nano-sized liposomes can pass through the disrupted BBB and accumulate in the I/R region, and that delivery of neuroprotective agents using a liposomal drug delivery system (DDS) is effective for the treatment of cerebral I/R injury. Moreover, we have recently demonstrated that combination therapy with liposomal drugs and t-PA can suppress the deleterious effects of t-PA and extend its TTW in a rat ischemic stroke model. These findings indicate that applications of nanoparticle DDS technology could be a hopeful approach to drug development for ischemic stroke therapy. In this review, we introduce our findings on ischemic stroke treatment using liposomal DDS and recent advances from other research groups.

Bioinformatics analysis identifies potential chemoresistance-associated genes across multiple types of cancer

Despite the fact that studies have revealed mechanisms underlying tumor chemoresistance, the functions of numerous potential chemoresistance-associated genes have yet to be elucidated. A bioinformatics analysis was conducted to screen differentially expressed genes (DEGs) across four types of chemoresistant tumors and functional enrichment analysis was used to examine the biological significance of these genes. Furthermore, a gene network was constructed using weighted gene co-expression network analysis to identify hub genes. A total of 6,015, 2,074, 2,141 and 954 differentially expressed genes were identified in estrogen receptor-negative breast cancer, ovarian cancer, rectal cancer and gastric cancer, respectively; however, only five of these DEGs were dysregulated in all four types of cancer. Functional enrichment analysis of the DEGs suggested that genomic stability and immune response are crucial determinants of tumor chemoresistance. In addition, 14, 8, 6 and 1 co-expressed gene modules were identified in estrogen receptor-negative breast cancer, ovarian cancer, rectal cancer and gastric cancer, respectively, and protein-protein interaction networks were created. The analysis identified only calcium-calmodulin-dependent protein kinase kinase 2, erythropoietin receptor, mitochondrial poly(A) RNA polymerase, α-parvin, and zinc finger and BTB domain-containing protein 44 to be dysregulated in all four cancer types, indicating varying mechanisms of chemoresistance in different tumor types. Furthermore, our analysis suggests that type I collagen α1, fibroblast growth factor 14 and major histocompatibility complex, class II, DR β1 potentially serve key roles in the development of chemoresistance. In conclusion, the present study proposes a simple and effective strategy for identifying genes involved in chemoresistance and predicting their potential functional roles, which may guide subsequent experimental studies.

Erythropoietin in ophthalmology: A literature review

PURPOSE

To review the current literature on ocular application of erythropoietin (EPO).

METHODS

A comprehensive search was performed on Pubmed and Scopus databases. All selected articles were reviewed thoroughly by the authors to review current applications of the EPO in ocular diseases.

RESULTS

Various aspects of administration of EPO for different ischemic, traumatic, vascular, and degenerative disorders have been explained. The articles are generally preclinical with few small studies reporting clinical outcomes.

CONCLUSION

EPO has been used for the treatment of different ophthalmic conditions with promising results. Further studies are needed to elaborate the role of EPO in management of ocular diseases.

The therapeutic potential of insulin-like growth factor-1 in central nervous system disorders

Central nervous system (CNS) development is a finely tuned process that relies on multiple factors and intricate pathways to ensure proper neuronal differentiation, maturation, and connectivity. Disruption of this process can cause significant impairments in CNS functioning and lead to debilitating disorders that impact motor and language skills, behavior, and cognitive functioning. Recent studies focused on understanding the underlying cellular mechanisms of neurodevelopmental disorders have identified a crucial role for insulin-like growth factor-1 (IGF-1) in normal CNS development. Work in model systems has demonstrated rescue of pathophysiological and behavioral abnormalities when IGF-1 is administered, and several clinical studies have shown promise of efficacy in disorders of the CNS, including autism spectrum disorder (ASD). In this review, we explore the molecular pathways and downstream effects of IGF-1 and summarize the results of completed and ongoing pre-clinical and clinical trials using IGF-1 as a pharmacologic intervention in various CNS disorders. This aim of this review is to provide evidence for the potential of IGF-1 as a treatment for neurodevelopmental disorders and ASD.

Application of cell encapsulation for controlled delivery of biological therapeutics

Cell microencapsulation technology is likely to have an increasingly important role in new approaches rather than the classical and pioneering organ replacement. Apart from becoming a tool for protein and morphogen release and long-term drug delivery, it is becoming a new three-dimensional platform for stem cell research. Recent progress in the field has resulted in biodegradable scaffolds that are able to retain and release the cell content in different anatomical locations. Additional advances include the use biomimetic scaffolds that provide greater control over material-cell interactions and the development of more precise encapsulated cell-tracking systems. This review summarises the state of the art of cell microencapsulation and discusses the main directions and challenges of this field towards the controlled delivery of biological therapeutics.

Review of recent studies on interventions for cognitive deficits in patients with cancer

Research has demonstrated that patients with cancer experience cognitive deficits, often due to aggressive anticancer treatments. In this article, we critically review the interventional studies that have been conducted to investigate beneficial effects on cognitive function in cancer patients. Pharmacological agents that have been studied include psychostimulants, such as methylphenidate and modafinil, erythropoietin, and hormonal (supplement) treatments for patients who receive hormonal suppression therapy. In addition, several cognitive rehabilitation programs have been evaluated in cancer patients. Recently, the approach of physical exercise to treat cognitive deficits has received great interest, and findings from novel studies are keenly anticipated. Although, in general, the studies reviewed were well designed, future studies may wish to include larger sample sizes and pay more attention to the accurate assessment of cognitive function.

A single injection of liposomal asialo-erythropoietin improves motor function deficit caused by cerebral ischemia/reperfusion

Modification of the liposomal surface with a targeting molecule is a promising approach for the targeted delivery of therapeutics. Asialo-erythropoietin (AEPO) is a potent tool for targeting an ischemic region by binding to the EPO receptors on neuronal cells. Additionally, it shows a strong cytoprotective effect against programed cell death. Hence, AEPO-modified liposomes appear likely to have both a neuronal-targeting character and a neuroprotective effect on cerebral ischemic injury. In this study, we assessed the targeting ability of AEPO-modified PEGylated liposomes (AEPO-liposomes) to ischemic region and their improvement effect on neurological deficits induced by ischemia/reperfusion (I/R) in transient middle cerebral artery occlusion (t-MCAO) rats. Immunohistological analysis showed that the AEPO-liposomes given immediately after reperfusion extravasated into the ischemic region and attached strongly to neuronal cells. Also, neuronal nuclei (NeuN) staining was clearly visible only in the AEPO-liposome-treated group, suggesting that AEPO-liposomes protected neuronal cells from ischemia/reperfusion-induced damage. Moreover, a single administration of low-dose AEPO-liposomes significantly improved the neurological deficit compared to vehicle and free-AEPO treatment at 7 days after injection. In conclusion, AEPO-liposomes have clear potential as a neuroprotectant after stroke and as a DDS device targeting ischemic regions.

Emerging technologies in the delivery of erythropoietin for therapeutics

Deciphering the function of proteins and their roles in signaling pathways is one of the main goals of biomedical research, especially from the perspective of uncovering pathways that may ultimately be exploited for therapeutic benefit. Over the last half century, a greatly expanded understanding of the biology of the glycoprotein hormone erythropoietin (Epo) has emerged from regulator of the circulating erythrocyte mass to a widely used therapeutic agent. Originally viewed as the renal hormone responsible for erythropoiesis, recent in vivo studies in animal models and clinical trials demonstrate that many other tissues locally produce Epo independent of its effects on red blood cell mass. Thus, not only its hematopoietic activity but also the recently discovered nonerythropoietic actions in addition to new drug delivery systems are being thoroughly investigated in order to fulfill the specific Epo release requirements for each therapeutic approach. The present review focuses on updating the information previously provided by similar reviews and recent experimental approaches are presented to describe the advances in Epo drug delivery achieved in the last few years and future perspectives.

Interventions for cognitive deficits in adults with brain tumours

Increased life expectancy in patients with brain tumours has led to a greater risk of cognitive deficits, particularly during disease-free periods. Here, we review the empirical studies that have been done to treat or to prevent cognitive impairment in patients with brain tumours. Both pharmacological interventions and cognitive rehabilitation programmes have been used. Although both types of study have reported some successes, these are often difficult to interpret owing to limitations in the methods used. Most of the studies reviewed did not use a randomised group design to control for possible confounding factors such as placebo and practice effects. Investigations of newer, targeted therapies have reported delays in cognitive deterioration, but these need to be confirmed in future studies. Neuroprotection represents another potentially promising, novel approach to prevention of cognitive impairment in this vulnerable population of patients. Finally, we describe studies in patients with cancers outside the CNS, to highlight further possibilities for the prevention and treatment of cognitive deficits.

Comparison of neuroprotective effects of erythropoietin (EPO) and carbamylerythropoietin (CEPO) against ischemia-like oxygen-glucose deprivation (OGD) and NMDA excitotoxicity in mouse hippocampal slice cultures

In addition to its well-known hematopoietic effects, erythropoietin (EPO) also has neuroprotective properties. However, hematopoietic side effects are unwanted for neuroprotection, underlining the need for EPO-like compounds with selective neuroprotective actions. One such compound, devoid of hematopoietic bioactivity, is the chemically modified, EPO-derivative carbamylerythropoietin (CEPO). For comparison of the neuroprotective effects of CEPO and EPO, we subjected organotypic hippocampal slice cultures to oxygen-glucose deprivation (OGD) or N-methyl-d-aspartate (NMDA) excitotoxicity. Hippocampal slice cultures were pretreated for 24 h with 100 IU/ml EPO (=26 nM) or 26 nM CEPO before OGD or NMDA lesioning. Exposure to EPO and CEPO continued during OGD and for the next 24 h until histology, as well as during the 24 h exposure to NMDA. Neuronal cell death was quantified by cellular uptake of propidium iodide (PI), recorded before the start of OGD and NMDA exposure and 24 h after. In cultures exposed to OGD or NMDA, CEPO reduced PI uptake by 49+/-3 or 35+/-8%, respectively, compared to lesion-only controls. EPO reduced PI uptake by 33+/-5 and 15+/-8%, respectively, in the OGD and NMDA exposed cultures. To elucidate a possible mechanism involved in EPO and CEPO neuroprotection against OGD, the integrity of alpha-II-spectrin cytoskeletal protein was studied. Both EPO and CEPO significantly reduced formation of spectrin cleavage products in the OGD model. We conclude that CEPO is at least as efficient neuroprotectant as EPO when excitotoxicity is modeled in mouse hippocampal slice cultures.

Induction of signalling in non-erythroid cells by pharmacological levels of erythropoietin

Erythropoiesis is maintained by the hormone erythropoietin (Epo) binding to its cognate receptor (EpoR) on erythroid progenitor cells. The Epo-EpoR interaction initiates a signal transduction process that regulates the survival, growth and differentiation of these cells. Originally perceived as highly lineage-restricted, Epo is now recognised to have pleiotropic effects extending beyond the maintenance of red cell mass. Functional interactions between Epo and EpoR have been demonstrated in numerous cells and tissues. EpoR expression on neoplastic cells leads to concern that recombinant human erythropoietin, used to treat anaemia in cancer patients, may augment tumour growth. Here we demonstrate that EPO, at pharmacological concentrations, can activate three major signalling cascades, viz. the Jak2/STAT5, Ras/ERK and PI3K/Akt pathways in non-small cell lung carcinoma (NSCLC) cell lines. EpoR synthesis is normally under the control of GATA-1, but NSCLC cells exhibit decreased GATA-1 levels compared to GATA-2, -3 and -6, suggesting that GATA-1 is not essential for EpoR production. The increased Epo-induced signalling was not associated with a growth advantage for the NSCLC cells.

The insulin-like growth factor system and its pleiotropic functions in brain

In recent years, much interest has been devoted to defining the role of the IGF system in the nervous system. The ubiquitous IGFs, their cell membrane receptors, and their carrier binding proteins, the IGFBPs, are expressed early in the development of the nervous system and are therefore considered to play a key role in these processes. In vitro studies have demonstrated that the IGF system promotes differentiation and proliferation and sustains survival, preventing apoptosis of neuronal and brain derived cells. Furthermore, studies of transgenic mice overexpressing components of the IGF system or mice with disruptions of the same genes have clearly shown that the IGF system plays a key role in vivo.

The electronic structure of human erythropoietin as an aid in the design of oxidation-resistant therapeutic proteins

The electronic structure of human erythropoietin (HuEPO) has been investigated with the aid of quantum mechanical calculations. The results indicate that the protein is highly polarized and its permanent dipole moment has a magnitude of 471 D. The HOMO of HuEPO is localized on Trp51, which stays in close proximity to Met54. Three oxidation-resistant mutants of HuEPO (W51F, M54V, and W51F-M54V) have been modeled and their electronic structures are compared to that of the native protein. Among them, the W51F mutation is predicted to be the most effective in increasing the oxidation potential of the protein.