Hypoxia-induced angiogenesis: good and evil

Local delivery of platelet-derived factors mitigates ischemia and preserves ovarian function through angiogenic modulation: A personalized regenerative strategy for fertility preservation

As the most prominent and ideal modality in female fertility preservation, ovarian tissue cryopreservation, and transplantation often confront the challenge of ischemic damage and follicular loss from avascular transplantation. To surmount this impediment, we engineered a novel platelet-derived factors-encapsulated fibrin hydrogel (PFH), a paradigmatic biomaterial. PFH encapsulates autologous platelet-derived factors, utilizing the physiological blood coagulation cascade for precise local delivery of bioactive molecules. In our study, PFH markedly bolstered the success of avascular ovarian tissue transplantation. Notably, the quantity and quality of follicles were preserved with improved neovascularization, accompanied by decreased DNA damage, increased ovulation, and superior embryonic development rates under a Low-concentration Platelet-rich plasma-derived factors encapsulated fibrin hydrogel (L-PFH) regimen. At a stabilized point of tissue engraftment, gene expression analysis mirrored normal ovarian tissue profiles, underscoring the effectiveness of L-PFH in mitigating the initial ischemic insult. This autologous blood-derived biomaterial, inspired by nature, capitalizes on the blood coagulation cascade, and combines biodegradability, biocompatibility, safety, and cost-effectiveness. The adjustable properties of this biomaterial, even in injectable form, extend its potential applications into the broader realm of personalized regenerative medicine. PFH emerges as a promising strategy to counter ischemic damage in tissue transplantation, signifying a broader therapeutic prospect. (197 words).

Understanding the molecular mechanism responsible for developing therapeutic radiation-induced radioresistance of rectal cancer and improving the clinical outcomes of radiotherapy - A review

Rectal cancer accounts for the second highest cancer-related mortality, which is predominant in Western civilizations. The treatment for rectal cancers includes surgery, radiotherapy, chemotherapy, and immunotherapy. Radiotherapy, specifically external beam radiation therapy, is the most common way to treat rectal cancer because radiation not only limits cancer progression but also significantly reduces the risk of local recurrence. However, therapeutic radiation-induced radioresistance to rectal cancer cells and toxicity to normal tissues are major drawbacks. Therefore, understanding the mechanistic basis of developing radioresistance during and after radiation therapy would provide crucial insight to improve clinical outcomes of radiation therapy for rectal cancer patients. Studies by various groups have shown that radiotherapy-mediated changes in the tumor microenvironment play a crucial role in developing radioresistance. Therapeutic radiation-induced hypoxia and functional alterations in the stromal cells, specifically tumor-associated macrophage (TAM) and cancer-associated fibroblasts (CAF), play a crucial role in developing radioresistance. In addition, signaling pathways, such as - the PI3K/AKT pathway, Wnt/β-catenin signaling, and the hippo pathway, modulate the radiation responsiveness of cancer cells. Different radiosensitizers, such as small molecules, microRNA, nanomaterials, and natural and chemical sensitizers, are being used to increase the effectiveness of radiotherapy. This review highlights the mechanism responsible for developing radioresistance of rectal cancer following radiotherapy and potential strategies to enhance the effectiveness of radiotherapy for better management of rectal cancer.

microRNAs: critical targets for treating rheumatoid arthritis angiogenesis

Vascular neogenesis, an early event in the development of rheumatoid arthritis (RA) inflammation, is critical for the formation of synovial vascular networks and plays a key role in the progression and persistence of chronic RA inflammation. microRNAs (miRNAs), a class of single-stranded, non-coding RNAs with approximately 21-23 nucleotides in length, regulate gene expression by binding to the 3' untranslated region (3'-UTR) of specific mRNAs. Increasing evidence suggests that miRNAs are differently expressed in diseases associated with vascular neogenesis and play a crucial role in disease-related vascular neogenesis. However, current studies are not sufficient and further experimental studies are needed to validate and establish the relationship between miRNAs and diseases associated with vascular neogenesis, and to determine the specific role of miRNAs in vascular development pathways. To better treat vascular neogenesis in diseases such as RA, we need additional studies on the role of miRNAs and their target genes in vascular development, and to provide more strategic references. In addition, future studies can use modern biotechnological methods such as proteomics and transcriptomics to investigate the expression and regulatory mechanisms of miRNAs, providing a more comprehensive and in-depth research basis for the treatment of related diseases such as RA.

Activation of the LKB1/AMPK/HIF-1α Pathway by Metformin to Promote Neovascularisation in Cerebral Ischaemia

As a difficult-to-treat neurological condition, cerebral ischemia is currently limited to treatments such as intravenous recombinant tissue plasminogen activator thrombolysis and thrombectomy. Metformin, a potent antidiabetic drug, has been reported to have an independent function in enhancing the prognosis of stroke patients, in addition to its glucose-lowering effects. However, the mechanism of action of metformin in this context remains unclear. In vivo, a rat model of permanent middle cerebral artery occlusion was established, and after administration of a low dose of 10.5 mg/mL metformin, infarct area was measured by TTC staining, and cortical blood flow was determined by laser Doppler imaging. In vitro, the study established human umbilical vein endothelial cells treated with cobalt chloride. Immunofluorescence, immunohistochemistry, and Western blot experiments were performed to observe the expression of angiogenic factors, tight junction proteins, and apoptotic factors. A TUNEL assay was utilized to appraise cell death by apoptosis. A tube formation assay and scratch assay were conducted to determine the endothelial neovascularization status. Animal experiments have revealed that the administration of the AMPK activator metformin significantly reduced the infarct area, promoted the expression of angiogenic factors, and maintained the stability of tight junction proteins in endothelial cells. Moreover, metformin reduces nerve cells apoptosis by affecting the expression of the apoptotic protein cleaved-caspase3 via the HIF-1α pathway. In vitro, the LKB1/AMPK signaling pathway is activated after hypoxic stimulation, attaining its peak within the early stages of hypoxia (1-12 h) and gradually weakening thereafter. The administration of AMPK pharmacological agonists (between 36 and 48 h) can enhance AMPK activity, which can lead to the expression of angiogenic factors, maintain the stability of tight-junction proteins in endothelial cells, and facilitate endothelial cell migration and vascular structure formation. Conversely, the AMPK inhibitors exert the opposite effects. The activation of the LKB1/AMPK/HIF-1α signaling pathway by metformin in cerebral ischemia contributes to angiogenesis, promotes tissue repair in the injured area, and enhances neurologically functional symptoms.

Hepatitis B virus X protein differentially regulates the angiogenesis of Hepatocellular Carcinoma through p53-VEGF axis according to glucose levels

INTRODUCTION AND OBJECTIVES

Blood glucose fluctuates severely in the diabetes (DM) and tumor microenvironment. Our previous works have found Hepatitis B virus X protein (HBx) differentially regulated metastasis and apoptosis of hepatoma cells depending on glucose concentration. We here aimed to explore whether HBx played dual roles in the angiogenesis of hepatocellular carcinoma varying on different glucose levels.

MATERIALS AND METHODS

We collected conditioned medium from HBx-overexpressing cells cultured with two solubilities of glucose, and then applied to EA.hy926 cells. Alternatively, a co-culture cell system was established with hepatoma cells and EA.hy926 cells. We analyzed the angiogenesis of EA.hy926 cells with CCK8, wound-healing, transwell-migartion and tube formation experiment. ELISA was conducted to detect the secretion levels of angiogenesis-related factors. siRNAs were used to detect the P53-VEGF axis.

RESULTS

HBx expressed in hepatoma cells suppressed VEGF secretion, and subsequently inhibited the proliferation, migration and tube formation of EA.hy926 cells in a high glucose condition, while attenuating these in the lower glucose condition. Furthermore, the p53-VEGF axis was required for the dual role of HBx in angiogenesis. Additionally, HBx mainly regulated the nuclear p53.

CONCLUSIONS

These data suggest that the dual roles of HBx confer hepatoma cells to remain in a glucose-rich environment and escape from the glucose-low milieu through tumor vessels, promoting liver tumor progression overall. We exclusively revealed the dual role of HBx on the angiogenesis of liver tumors, which may shed new light on the mechanism and management strategy of HBV- and DM-related hepatocellular carcinoma.

Unlocking vinpocetine's oncostatic potential in early-stage hepatocellular carcinoma: A new approach to oncogenic modulation by a nootropic drug

The development of new drugs for the inhibition of hepatocellular carcinoma (HCC) development and progression is a critical and urgent need. The median survival rate for HCC patients remains disappointingly low. Vinpocetine is a safe nootropic agent that is often used to enhance cognitive function. The impact of vinpocetine on HCC development and progression has not been fully explored. Our main objective was to investigate the possible inhibitory role of vinpocetine in rats exposed to diethylnitrosamine. We observed that vinpocetine increased the survival rate of these rats and improved the ultrastructure of their livers. Additionally, vinpocetine reduced the liver weight index, mitigated liver oxidative stress, and improved liver function. In both in vitro and in vivo settings, vinpocetine demonstrated antiproliferative and apoptotic properties. It downregulated the expression of CCND1 and Ki-67 while exhibiting anti-BCL-2 effects and enhancing the levels of Bax and cleaved caspase-3. Vinpocetine also successfully deactivated NF-κB, STAT3, and HIF-1α, along with their associated transcription proteins, thereby exerting anti-inflammatory and anti-angiogenic role. Furthermore, vinpocetine showed promise in reducing the levels of ICAM-1 and TGF-β1 indicating its potential role in tissue remodeling. These findings strongly suggest that vinpocetine holds promise as a hepatoprotective agent by targeting a range of oncogenic proteins simultaneously. However, further approaches are needed to validate and establish causal links between our observed effects allowing for a more in-depth exploration of the mechanisms underlying vinpocetine's effects and identifying pivotal determinants of outcomes.

Physiological and tumor-associated angiogenesis: Key factors and therapy targeting VEGF/VEGFR pathway

Cancer remains one of the leading causes of death worldwide and poses a significant challenge to effective treatment due to its complexity. Angiogenesis, the formation of new blood vessels, is one of the cancer hallmarks and is a critical process in tumor growth and metastasis. The pivotal role of angiogenesis in cancer development has made antiangiogenic treatment a promising strategy for cancer therapy. To develop an effective therapy, it is essential to understand the basics of the physiological and tumor angiogenesis process. This review presents the primary factors related to physiological and tumor angiogenesis and the mechanisms of angiogenesis in tumors. We summarize potential molecular targets for cancer treatment by focusing on the vasculature, with the VEGF/VEGFR pathway being one of the most important and well-studied. Additionally, we present the advantages and limitations of currently used clinical protocols for cancer treatment targeting the VEGF/VEGFR pathway.

Emergence of cyclic hypoxia and the impact of PARP inhibitors on tumor progression

Tumor hypoxia is a dynamic phenomenon marked by fluctuations in oxygen levels across both rapid (seconds to minutes) and slow (hours to days) time scales. While short hypoxia cycles are relatively well understood, the mechanisms behind longer cycles remain largely unclear. In this paper, we present a novel mechanistic mathematical model that explains slow hypoxia cycles through feedback loops involving vascular expansion and regression, oxygen-regulated tumor growth, and toxic cytokine production. Our study reveals that, for the emergence of slow hypoxia cycles, endothelial cells must adapt by decreasing receptor activation as ligand concentration increases. Additionally, the interaction between tumor cells and toxic cytokines influences frequency and intensity of these cycles. By examining the effects of pharmacological interventions, specifically poly (ADP-ribose) polymerase inhibitors, we also demonstrate how targeting cell proliferation can help regulate oxygen levels. Our findings enhance the understanding of hypoxia regulation and suggest PARP proteins as promising therapeutic targets.

Highly porous polycaprolactone microspheres for skeletal repair promote a mature bone cell phenotype in vitro

Improving our ability to treat skeletal defects is a critical medical challenge that necessitates the development of new biomaterials. One promising approach involves the use of degradable polymer microparticles with an interconnected internal porosity. Here, we employed a double emulsion to generate such round microparticles (also known as microspheres) from a polycaprolactone-based polymerised high internal phase emulsion (polyHIPE). These microspheres effectively supported the growth of mesenchymal progenitors over a 30-day period, and when maintained in osteogenic media, cells deposited a bone-like extracellular matrix, as determined by histological staining for calcium and collagen. Interestingly, cells with an osteocyte-like morphology were observed within the core of the microspheres indicating the role of a physical environment comparable to native bone for this phenotype to occur. At later timepoints, these cultures had significantly increased mRNA expression of the osteocyte-specific markers dentin matrix phosphoprotein-1 (Dmp-1) and sclerostin, with sclerostin also observed at the protein level. Cells pre-cultured on porous microspheres exhibited enhanced survival rates compared to those pre-cultured on non-porous counterparts when injected. Cells precultured on both porous and non-porous microspheres promoted angiogenesis in a chorioallantoic membrane (CAM) assay. In summary, the polycaprolactone polyHIPE microspheres developed in this study exhibit significant promise as an alternative to traditional synthetic bone graft substitutes, offering a conducive environment for cell growth and differentiation, with the potential for better clinical outcomes in bone repair and regeneration.

Heyde Syndrome Unveiled: A Case Report with Current Literature Review and Molecular Insights

Heyde syndrome, marked by aortic stenosis, gastrointestinal bleeding from angiodysplasia, and acquired von Willebrand syndrome, is often underreported. Shear stress from a narrowed aortic valve degrades von Willebrand factor multimers, leading to angiodysplasia formation and von Willebrand factor deficiency. This case report aims to raise clinician awareness of Heyde syndrome, its complexity, and the need for a multidisciplinary approach. We present a 75-year-old man with aortic stenosis, gastrointestinal bleeding from angiodysplasia, and acquired von Willebrand syndrome type 2A. The patient was successfully treated with argon plasma coagulation and blood transfusions. He declined further treatment for aortic stenosis but was in good overall health with improved laboratory results during follow-up. Additionally, we provide a comprehensive review of the molecular mechanisms involved in the development of this syndrome, discuss current diagnostic and treatment approaches, and offer future perspectives for further research on this topic.

Unraveling the role of HIF and epigenetic regulation in pulmonary arterial hypertension: implications for clinical research and its therapeutic approach

Pulmonary arterial hypertension (PAH) is characterized by pulmonary vascular remodeling with high pulmonary pressure, which ultimately leads to right heart failure and premature death. Emerging evidence suggests that both hypoxia and epigenetics play a pivotal role in the pathogenesis of PAH development. In this review article, we summarize the current developments in regulation of hypoxia inducible factor (HIF) isoforms in PAH vascular remodeling and the development of suitable animal models for discovery and testing of HIF pathway-targeting PAH therapeutics. In addition, we also discuss the epigenetic regulation of HIF-dependent isoforms in PAH and its therapeutic potential from a new perspective which highlights the importance of HIF isoform-specific targeting as a novel salutary strategy for PAH treatment.

The Role of Pericytes in Inner Ear Disorders: A Comprehensive Review

Inner ear disorders, including sensorineural hearing loss, Meniere's disease, and vestibular neuritis, are prevalent conditions that significantly impact the quality of life. Despite their high incidence, the underlying pathophysiology of these disorders remains elusive, and current treatment options are often inadequate. Emerging evidence suggests that pericytes, a type of vascular mural cell specialized to maintain the integrity and function of the microvasculature, may play a crucial role in the development and progression of inner ear disorders. The pericytes are present in the microvasculature of both the cochlea and the vestibular system, where they regulate blood flow, maintain the blood-labyrinth barrier, facilitate angiogenesis, and provide trophic support to neurons. Understanding their role in inner ear disorders may provide valuable insights into the pathophysiology of these conditions and lead to the development of novel diagnostic and therapeutic strategies, improving the standard of living. This comprehensive review aims to provide a detailed overview of the role of pericytes in inner ear disorders, highlighting the anatomy and physiology in the microvasculature, and analyzing the mechanisms that contribute to the development of the disorders. Furthermore, we explore the potential pericyte-targeted therapies, including antioxidant, anti-inflammatory, and angiogenic approaches, as well as gene therapy strategies.

Metachromin C, a marine-derived natural compound, shows potential in antitumor activity

Metachromin C was first isolated from the marine sponge Hippospongia metachromia and has been reported to possess potent cytotoxicity against leukemia cells. However, its antitumor activity and possible mechanisms in pancreatic cancer remain unclear. The effects of Metachromin C on cell viability were estimated using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. The compound demonstrated a cytotoxic effect on four pancreatic cancer cell lines (PANC-1, BxPC-3, MiaPaCa-2, and AsPC-1). The significant S phase arrest observed with Metachromin C treatment suggests its impact on DNA replication machinery. Metachromin C might interfere with the binding of Topoisomerase I (TOPO I) to DNA, inhibit TOPO I activity, prevent DNA relaxation, cause DNA damage, and consequently activate the DNA repair pathway. Additionally, anti-migration and anti-invasion abilities of Metachromin C were confirmed using the transwell assay. It also inhibited angiogenesis in human endothelial cells by reducing cell proliferation, migration, and disrupting tube formation. Moreover, Metachromin C dose-dependently inhibited the growth of intersegmental vessels, subintestinal vessels, and the caudal vein plexus in a zebrafish embryo model, confirming its inhibitory effect on new vessel formation in vivo. Taken together, Metachromin C could not only inhibit the growth of pancreatic cancer cells but also act as an anti-angiogenic compound simultaneously.

Emerging understandings of the role of exosomes in atherosclerosis

Atherosclerosis remains a major contributor to cardiovascular disease, the leading cause of global morbidity and mortality. Despite the elucidation of several molecular, biochemical, and cellular aspects that contribute to the etio-pathogenesis of atherosclerosis, much remains to be understood about the onset and progression of this disease. Emerging evidence supports a role for exosomes in the cellular basis of atherosclerosis. Indeed, exosomes of activated monocytes seem to accentuate a positive feedback loop that promotes recruitment of pro-inflammatory leukocytes. Moreover, in addition to their role in promoting proliferation and invasion of vascular smooth muscle cells, exosomes can also induce neovascularization within lesions and increase endothelial permeability, two important features of fibrous plaques. Depending on their sources and cargo, exosomes can also induce clot formation and contribute to other hallmarks of atherosclerosis. Taken together, it is becoming increasingly evident that a better understanding of exosome biology is integral to elucidating the pathogenesis of atherosclerosis, and may thus provide insight into a potentially new therapeutic target for this disease.

Sera from Rheumatoid Arthritis Patients Induce Oxidative Stress and Pro-Angiogenic and Profibrotic Phenotypes in Human Endothelial Cells

Background: Rheumatoid arthritis (RA) is a long-term autoimmune condition marked by persistent inflammation of the joints and various systemic complications, including endothelial dysfunction, atherosclerosis, and pulmonary fibrosis. Oxidative stress is a key contributor to the pathogenesis of RA, potentially exacerbating vascular damage and promoting pro-angiogenic and profibrotic processes. Objective: This study aims to investigate the effects of sera from RA patients on human umbilical vein endothelial cells (HUVECs), focusing on the induction of oxidative stress, endothelial cell proliferation, migration, and collagen type I synthesis. Methods: Twenty-eight serum samples were collected from RA patients and healthy donors (HDs). HUVECs were exposed to these sera, and intracellular reactive oxygen species (ROS) levels were fluorescently detected using H2DCF-DA. Cell viability was assessed using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Cell migration was evaluated through a scratch wound assay, and collagen type I synthesis was measured using a lentiviral vector expressing the green fluorescent protein (GFP) under the control of the human COL1A1 gene promoter. Results: Exposure to RA sera resulted in a significant increase in intracellular ROS levels in HUVECs compared to HD sera, indicating an elevated state of oxidative stress. RA sera also promoted endothelial cell proliferation and migration, suggesting a pro-angiogenic stimulus. Additionally, RA sera significantly increased collagen type I synthesis in HUVECs, implicating a potential role in profibrotic processes associated with RA. Conclusion: The results of this study emphasize the importance of circulating factors in RA sera in promoting oxidative stress, endothelial dysfunction, and pro-angiogenic and profibrotic phenotypes in endothelial cells. These processes may contribute to the vascular and fibrotic complications observed in RA, highlighting the necessity for additional research into focused therapeutic approaches to alleviate these effects.

Analysis of RNA Interference Targeted Against Human Antigen R (HuR) to Reduce Vascular Endothelial Growth Factor (VEGF) Protein Expression in Human Retinal Pigment Epithelial Cells

VEGF-A or vascular endothelial growth factor-A is an important factor in enabling neovascularization and angiogenesis. VEGF-A is regulated transcriptionally as well as post transcriptionally. Human antigen R (HuR) belonging to the embryonic lethal abnormal vision (ELAV) family is a key regulator promoting stabilization of VEGF-A mRNA. In this research we investigate, whether HuR targeted RNA interference would enable the reduction of the VEGF-A protein in human retinal pigment epithelial cells (ARPE-19) in-vitro, in normoxic conditions. Three siRNA molecules with sequences complementary to three regions of the HuR mRNA were designed. The three designed siRNA molecules were individually transfected in ARPE-19 cells using Lipofectamine™2000 reagent. Post-transfection (24 h, 48 h, 72 h), downregulation of HuR mRNA was estimated by real-time polymerase reaction, while HuR protein and VEGF-A protein levels were semi-quantitatively determined by western blotting techniques. VEGF-A protein levels were additionally quantified using ELISA techniques. All experiments were done in triplicate. The designed siRNA could successfully downregulate HuR mRNA with concomitant decreases in HuR and VEGF-A protein. The study reveals that HuR downregulation can prominently downregulate VEGF-A, making the protein a target for therapy against pathological angiogenesis conditions such as diabetic retinopathy.

Effect of the gonadotropin surge on steroid receptor regulation in preovulatory follicles and newly formed corpora lutea in the cow

The objective of the study was to characterize the mRNA expression patterns of specific steroid hormone receptors namely, estrogen receptors (ESRRA-estrogen related receptor alpha and ESRRB-estrogen related receptor beta) and progesterone receptors (PGR) in superovulation-induced bovine follicles during the periovulation and subsequent corpus luteum (CL) formation. The bovine ovaries (n = 5 cow / group), containing preovulatory follicles or early CL, were collected relative to injection of the gonadotropin-releasing hormone (GnRH) at (I) 0 h, (II) 4 h, (III) 10 h, (IV) 20 h, (V) 25 h (preovulatory follicles) and (VI) 60 h (CL, 2-3 days after induced ovulation). In this experiment, we analyzed the steroid receptor mRNA expression and their localization in the follicle and CL tissue. The high mRNA expression of ESRRA, ESRRB, and PGR analyzed in the follicles before ovulation is significantly reduced in the group of follicles during ovulation (25 h after GnRH), rising again significantly after ovulation in newly formed CL, only for ESRRA and PGR (P < 0.05). Immunohistochemically, the nuclei of antral follicles' granulosa cells showed a positive staining for ESRRA, followed by higher activity in the large luteal cells just after ovulation (early CL). In contrast, the lower PGR immunopresence in preovulatory follicles increased in both small and large luteal cell nuclei after follicle ovulation. Our results of steroid receptor mRNA expression in this experimentally induced gonadotropin surge provide insight into the molecular mechanisms of the effects of steroid hormones on follicular-luteal tissue in the period close to the ovulation and subsequent CL formation in the cow.

Brain Microvascular Pericyte Pathology Linking Alzheimer's Disease to Diabetes

The brain microvasculature, which delivers oxygen and nutrients and forms a critical barrier protecting the central nervous system via capillaries, is deleteriously affected by both Alzheimer's disease (AD) and type 2 diabetes (T2D). T2D patients have an increased risk of developing AD, suggesting potentially related microvascular pathological mechanisms. Pericytes are an ideal cell type to study for functional links between AD and T2D. These specialized capillary-enwrapping cells regulate capillary density, lumen diameter, and blood flow. Pericytes also maintain endothelial tight junctions to ensure blood-brain barrier integrity, modulation of immune cell extravasation, and clearance of toxins. Changes in these phenomena have been observed in both AD and T2D, implicating "pericyte pathology" as a common feature of AD and T2D. This review examines the mechanisms of AD and T2D from the perspective of the brain microvasculature, highlighting how pericyte pathology contributes to both diseases. Our review identifies voids in understanding how AD and T2D negatively impact the brain microvasculature and suggests future studies to examine the intersections of these diseases.

Hypoxia-Inducible Factor 1-Alpha (HIF-1α) and Cancer: Mechanisms of Tumor Hypoxia and Therapeutic Targeting

Hypoxia-inducible factor 1-alpha (HIF-1α) is necessary for cells to adapt to low oxygen levels often present in the tumor microenvironment. HIF-1α triggers a transcriptional program that promotes invasion, angiogenesis, metabolic reprogramming, and cell survival when it is active in hypoxic environments. These processes together lead to the growth and spread of tumors. This review article examines the molecular mechanisms by which HIF-1α contributes to tumor progression, including its regulation by oxygen-dependent and independent pathways, interactions with oncogenic signaling networks, and impact on the tumor microenvironment. Additionally, we explore current therapeutic strategies targeting HIF-1α, such as small molecule inhibitors, RNA interference, and immunotherapy approaches. Understanding the multifaceted roles of HIF-1α in cancer biology not only elucidates the complexities of tumor hypoxia but also opens avenues for developing novel and more effective cancer therapies.

Three-Dimensional In Vitro Cell Cultures as a Feasible and Promising Alternative to Two-Dimensional and Animal Models in Cancer Research

Cancer represents one of the diseases with the highest mortality rate worldwide. The burden of cancer continues to increase, not only affecting the health-related quality of life of patients but also causing an elevated global financial impact. The complexity and heterogeneity of cancer pose significant challenges in research and clinical practice, contributing to increase the failure rate of clinical trials for antitumoral drugs. This is partially due to the fact that preclinical models still present important limitations in faithfully recapitulating human tumors to serve as reliable indicators of drug effectiveness. Up to now, research and development strategies employ expensive animal models (including the so-called "humanized mice") that not only raise ethical concerns, but also frequently fail to accurately predict responses to anticancer drugs because they do not faithfully replicate human physiology as well as the patient's tumor microenvironment. On the other side, traditional two-dimensional (2D) cell cultures fail to adequately reproduce the structural organization of tumor and the cellular heterogeneity found in vivo. The growing necessity to develop more accurate cancer models has increasingly emphasized the importance of three-dimensional (3D) in vitro cell cultures, such as cancer-derived spheroids and organoids, as promising alternatives to bridge the gap between 2D and animal models. In this review, we provide a brief overview focusing on 3D in vitro cell cultures as preclinical models capable of properly reproducing the tissue organization, biological composition, and complexity of in vivo tumors in a fine-tuned microenvironment. Despite their limitations, these models collectively enhance our understanding of the mechanisms underlying cancer and may offer the potential for a more reliable assessment of drug efficacy before clinical testing and, consequently, improve therapeutic outcomes for cancer patients.

Targeting Hypoxia-Inducible Factor-1α in Pancreatic Cancer: siRNA Delivery Using Hyaluronic Acid-Displaying Nanoparticles

Background/Objectives: Conventional anticancer therapies often lack specificity, targeting both cancerous and normal cells, which reduces efficacy and leads to undesired off-target effects. An additional challenge is the presence of hypoxic regions in tumors, where the Hypoxia Inducible Factor (HIF) transcriptional system drives the expression of pro-survival and drug resistance genes, leading to radio- and chemo-resistance. This study aims to explore the efficacy of targeted nanoparticle (NP)-based small interfering RNA (siRNA) therapies in downregulating these genes to enhance treatment outcomes in pancreatic cancer, a tumor type characterized by high CD44 expression and hypoxia. Methods: We utilized hyaluronic acid (HA)-displaying nanoparticles composed of positively charged chitosan (CS) complexed with siRNA to target and knock down HIF-1α in pancreatic cancer cells. Two NP formulations were prepared using either low molecular weight (LMW) or high molecular weight (HMW) CS. These formulations were evaluated for their internalization by cells and their effectiveness in gene silencing, both in vitro and in vivo. Results: The study found that the molecular weight (MW) of CS influenced the interaction between HA and CD44, as well as the release of siRNA upon internalization. The LMW CS formulation shows faster uptake kinetics, while HMW CS is more effective in gene knockdown across different cell lines in vitro. In vivo, both were able to significantly knockdown HIF-1α and some of its downstream genes. Conclusions: The results suggest that HMW and LMW CS-based NPs exhibit distinct characteristics, showing that both MWs have potential for targeted pancreatic cancer therapy by influencing different aspects of delivery and gene silencing, particularly in the hypoxic tumor microenvironment.

Oncogenic potential of SARS-CoV-2-targeting hallmarks of cancer pathways

The 2019 outbreak of SARS-CoV-2 has caused a major worldwide health crisis with high rates of morbidity and death. Interestingly, it has also been linked to cancer, which begs the issue of whether it plays a role in carcinogenesis. Recent studies have revealed various mechanisms by which SARS-CoV-2 can influence oncogenic pathways, potentially promoting cancer development. The virus encodes several proteins that alter key signaling pathways associated with cancer hallmarks. Unlike classical oncogenic viruses, which transform cells through viral oncogenes or by activating host oncogenes, SARS-CoV-2 appears to promote tumorigenesis by inhibiting tumor suppressor genes and pathways while activating survival, proliferation, and inflammation-associated signaling cascades. Bioinformatic analyses and experimental studies have identified numerous interactions between SARS-CoV-2 proteins and cellular components involved in cancer-related processes. This review explores the intricate relationship between SARS-CoV-2 infection and cancer, focusing on the regulation of key hallmarks driving initiation, promotion and progression of cancer by viral proteins. By elucidating the underlying mechanisms driving cellular transformation, the potential of SARS-CoV-2 as an oncovirus is highlighted. Comprehending these interplays is essential to enhance our understanding of COVID-19 and cancer biology and further formulating strategies to alleviate SARS-CoV-2 influence on cancer consequences.

Exploring angiogenic pathways in breast cancer: Clinicopathologic correlations and prognostic implications based on gene expression profiles from a large-scale genomic dataset

BACKGROUND

Angiogenesis inhibitors targeting VEGF, or its receptors have consistently produced disappointing clinical outcomes in breast cancer. Therefore, there is an urgent need to explore alternative angiogenic pathways in breast cancer. This study aimed to describe the gene expression of pivotal pro-angiogenic genes in breast cancer and to further analyze the associations with the clinicopathologic tumor features, prognostic factors, and overall survival. Such findings would expand the understanding of the role of different angiogenic pathways in breast cancer pathogenesis and identify patients at risk of more aggressive disease who could be eligible for intense treatment regimens. Additionally, exploring angiogenic pathways helps identify new potential drug targets for breast cancer.

METHODS

The mRNA expression levels for eight pro-angiogenic genes [VEGFA, HGF, FGF1, FGF2, ANGPT1, ANGPT2, PDGFA, and PDGFB] were obtained from the METABRIC (Molecular Taxonomy of Breast Cancer International Consortium) dataset available at cBioPortal public domain. Pertinent demographic and tumor information were retrieved.

RESULTS

VEGFA and ANGPT2 genes had the highest expression levels with average mRNA log intensities of 7.18±0.7 and 7.11±0.53, respectively. VEGFA expression was not correlated with the expression of other pro-angiogenic genes, the clinicopathologic tumor features, and the overall survival of patients. FGF1, ANGPT1, and PDGFA mRNA levels were negatively correlated with the age of patients at diagnosis. The expression of FGF1 and FGF2 correlated inversely with tumor size and the Nottingham Prognostic Index (p = 0.03 and p = 0.002, respectively). Expression of HGF was significantly associated with advanced tumor stage (p<0.05). Expression of ANGPT1 and ANGPT2 was associated with hormone receptor-negative status and the non-luminal subtypes. PDGFB expression was significantly higher in patients with high-grade disease and HER2-positive status. Patients with high expression status of ANGPT2 and PDGFB had significantly reduced overall survival compared to those with low expression levels of these genes (p = 0.004 and p = 0.0001, respectively).

CONCLUSIONS

In this dataset of patients with breast cancer, the expression levels of 8 different pro-angiogenic genes revealed remarkable differences in terms of their association with clinicopathologic tumor characteristics and prognosis. The expression of ANGPTs and PDGFs was associated with adverse tumor features, worse prognosis, and reduced survival in patients. Targeting ANGPTs and PDGF pathways could provide new insights for effective anti-angiogenic drugs in breast cancer.

Beyond genetics: integrative oncology and the metabolic perspective on cancer treatment

Cancer is traditionally approached as a genetic disease, with standard treatments including chemotherapy, radiation, targeted therapy, immunotherapy, and surgery significantly improving survival rates and patient outcomes. However, there is a growing recognition of the need for integrative oncology, which expands cancer management by considering cancer as a metabolic disease. Integrative medicine physicians employ holistic therapies focused on patients' needs, aiming to correct the metabolic imbalances associated with cancer and alleviate cancer-related symptoms. Viewing cancer as a metabolic disease involves addressing factors such as an acidic microenvironment, vitamin C deficiency, mitochondrial dysfunction, reduced intracellular oxygen levels, elevated oxidative stress, dysfunctional autophagy, and psychological stress. This paper presents an overview of the evidence and comprehensive strategies supporting integrative medicine approaches in addressing cancer metabolism in integrative oncology settings. Furthermore, the paper underscores the necessity of integrating different cancer theories-genetic and metabolic-for improved patient outcomes and experiences. By combining these perspectives, integrative oncology offers a more holistic, patient-centered approach to cancer treatment.

Decoding Cold Therapy Mechanisms of Enhanced Bone Repair through Sensory Receptors and Molecular Pathways

Applying cold to a bone injury can aid healing, though its mechanisms are complex. This study investigates how cold therapy impacts bone repair to optimize healing. Cold was applied to a rodent bone model, with the physiological responses analyzed. Vasoconstriction was mediated by an increase in the transient receptor protein channels (TRPs), transient receptor potential ankyrin 1 (TRPA1; p = 0.012), and transient receptor potential melastatin 8 (TRPM8; p < 0.001), within cortical defects, enhancing the sensory response and blood flow regulation. Cold exposure also elevated hypoxia (p < 0.01) and vascular endothelial growth factor expression (VEGF; p < 0.001), promoting angiogenesis, vital for bone regeneration. The increased expression of osteogenic proteins peroxisome proliferator-activated receptor gamma coactivator (PGC-1α; p = 0.039) and RNA-binding motif protein 3 (RBM3; p < 0.008) suggests that the reparative processes have been stimulated. Enhanced osteoblast differentiation and the presence of alkaline phosphatase (ALP) at day 5 (three-fold, p = 0.021) and 10 (two-fold, p < 0.001) were observed, along with increased osteocalcin (OCN) at day 10 (two-fold, p = 0.019), indicating the presence of mature osteoblasts capable of mineralization. These findings highlight cold therapy's multifaceted effects on bone repair, offering insights for therapeutic strategies.

Zanzalintinib (XL092): a next-generation tyrosine kinase inhibitor-comprehensive review of early safety & efficacy data

INTRODUCTION

Zanzalintinib (XL092) is a next-generation anti-VEGFR-related multi-targeted TKI that exhibits immunomodulatory effects.

AREAS COVERED

This review explores preclinical and clinical data, along with the future directions associated with zanzalintinib and its combination with immune checkpoint inhibitors (ICIs).

EXPERT OPINION

In addition to its anti-VEGFR activity, zanzalintinib demonstrates potential synergistic effects with ICIs through its immunomodulatory impact, attributed to its inhibition of MET and TAM kinases. Recent preclinical studies provide compelling evidence supporting this synergistic potential. Furthermore, a recent phase 1 dose escalation study confirmed the tolerability of the zanzalintinib and anti-PDL1 combination without major safety concerns.Multiple ongoing clinical trials are investigating the combination of zanzalintinib and ICIs across various solid tumor types, including phase 3 studies for renal cell carcinoma, colorectal, and head and neck cancer. These trials aim to elucidate the therapeutic role of this new-generation TKI and ICI combination.However, the identification of reliable predictive biomarkers for the zanzalintinib and ICI combination presents significant challenges. Given the intricate nature of their mechanistic rationale and the difficulties in identifying reliable biomarkers for combined anti-angiogenesis and ICI therapies, addressing this challenge remains a priority for ongoing and future research.

Improved Composite Hydrogel for Bioengineered Tracheal Graft Demonstrates Effective Early Angiogenesis

Background/Objectives: Collagen-agarose hydrogel blends currently used in tracheal graft bioengineering contain relatively high concentrations of collagen to withstand mechanical stresses associated with native trachea function (e.g., breathing). Unfortunately, the high collagen content restricts effective cell infiltration into the hydrogel. In this study, we created an improved hydrogel blend with lower concentrations of collagen (<5 mg/mL) and characterized its capacity for fibroblast invasion and angiogenesis. Methods: Four collagen-agarose hydrogel blends were created: 1 mg/mL type 1 collagen (T1C) and 0.25% agarose, 1 mg/mL T1C and 0.125% agarose, 2 mg/mL T1C and 0.25% agarose, and 2 mg/mL T1C and 0.125% agarose. The hydrogel surface was seeded with fibroblasts, while both endothelial cells and fibroblasts (3:1 ratio) were mixed within the hydrogel matrix. We assessed early angiogenesis by observing fibroblast migration and endothelial cell morphology (elongation and branching) at 7 days. In addition, we performed immunostaining for alpha-smooth muscle actin (aSMA) and explored the gene expression of various angiogenic markers (including vascular endothelial growth factor; VEGF). Results: Gels with lower agarose concentrations (0.125%) with 1 or 2 mg/mL T1C were more effective in allowing early attachment and migration of surface-applied fibroblasts compared to gels with higher (0.25%) agarose concentrations. The low-agarose gels also allowed cells to quickly adopt a spread morphology and self-assemble into elongated structures indicative of early angiogenesis, while demonstrating positive immunostaining for aSMA and increased gene expression of VEGF by day 7. Conclusions: Hydrogel blends with collagen and low agarose concentrations may be effective in allowing early cellular infiltration and angiogenesis, making such gels a suitable cell substrate for use in the development of composite bioengineered tracheal grafts. The collagen-agarose hydrogel blend is meant to be cast around a three-dimensional (3D) printed polycaprolactone support structure and wrapped in porcine small intestine submucosa ECM to create an off-the-shelf bioengineered tracheal implant.

From Crypts to Cancer: A Holistic Perspective on Colorectal Carcinogenesis and Therapeutic Strategies

Colorectal cancer (CRC) represents a significant global health burden, with high incidence and mortality rates worldwide. Recent progress in research highlights the distinct clinical and molecular characteristics of colon versus rectal cancers, underscoring tumor location's importance in treatment approaches. This article provides a comprehensive review of our current understanding of CRC epidemiology, risk factors, molecular pathogenesis, and management strategies. We also present the intricate cellular architecture of colonic crypts and their roles in intestinal homeostasis. Colorectal carcinogenesis multistep processes are also described, covering the conventional adenoma-carcinoma sequence, alternative serrated pathways, and the influential Vogelstein model, which proposes sequential APC, KRAS, and TP53 alterations as drivers. The consensus molecular CRC subtypes (CMS1-CMS4) are examined, shedding light on disease heterogeneity and personalized therapy implications.

The angiogenic role of the alpha 9-nicotinic acetylcholine receptor in triple-negative breast cancers

Nicotine acts as an angiogenic factor by stimulating endogenous cholinergic pathways. Several subtypes of nicotinic acetylcholine receptors (nAChRs) have been demonstrated to be closely correlated to the formation and progression of different types of cancers. Recently, several studies have found that nicotinic acetylcholine receptors α9 (α9-nAChRs) are highly expressed in breast tumors, especially in tumors derived from patients diagnosed at advanced stages. In vitro studies have demonstrated that activation of α9-nAChRs is associated with increased proliferation and migration of breast cancer. To study the tumor-promoting role of α9-nAChRs in breast cancers, we generated a novel anti-α9-nAChR and methoxy-polyethylene glycol (mPEG) bispecific antibody (α9 BsAb) for dissecting the molecular mechanism on α9-nAChR-mediated tumor progression. Unexpectedly, we discovered the angiogenic role of α9-nAChR in nicotine-induced neovascularization of tumors. It revealed α9 BsAbs reduced nicotine-induced endothelial cell tube formation, blood vessel development in Matrigel plug assay and angiogenesis in microtube array membrane murine model (MTAMs). To unbraid the molecular mechanism of α9-nAChR in nicotine-mediated angiogenesis, the α9 BsAbs were applied and revealed the inhibitory roles in nicotine-induced production of hypoxia-inducible factor-2 alpha (HIF-2α), vascular endothelial growth factor A (VEGF-A), phosphorylated vascular endothelial growth factor receptor 2 (p-VEGFR2), vascular endothelial growth factor receptor 2 (VEGFR2) and matrix metalloproteinase-9 (MMP9) from triple-negative breast cancer cells (MDA-MB-231), suggesting α9-nAChRs played an important role in nicotine-induced angiogenesis. To confirm our results, the shRNA targeting α9-nAChRs was designed and used to silence α9-nAChR expression and then evaluated the angiogenic role of α9-nAChRs. The results showed α9 shRNA also played an inhibitory effect in blocking the nicotine-induced angiogenic signaling. Taken together, α9-nAChR played a critical role in nicotine-induced angiogenesis and this bispecific antibody (α9 BsAb) may serve as a potential therapeutic candidate for treatments of the α9 positive cancers.

GWAS-significant loci and severe COVID-19: analysis of associations, link with thromboinflammation syndrome, gene-gene, and gene-environmental interactions

Objective

The aim of this study was to replicate associations of GWAS-significant loci with severe COVID-19 in the population of Central Russia, to investigate associations of the SNPs with thromboinflammation parameters, to analyze gene-gene and gene-environmental interactions.

Materials and Methods

DNA samples from 798 unrelated Caucasian subjects from Central Russia (199 hospitalized COVID-19 patients and 599 controls with a mild or asymptomatic course of COVID-19) were genotyped using probe-based polymerase chain reaction for 10 GWAS-significant SNPs: rs143334143 CCHCR1, rs111837807 CCHCR1, rs17078346 SLC6A20-LLZTFL1, rs17713054 SLC6A20-LLZTFL1, rs7949972 ELF5, rs61882275 ELF5, rs12585036 ATP11A, rs67579710 THBS3, THBS3-AS1, rs12610495 DPP9, rs9636867 IFNAR2.

Results

SNP rs17713054 SLC6A20-LZTFL1 was associated with increased risk of severe COVID-19 in the entire group (risk allele A, OR = 1.78, 95% CI = 1.22-2.6, p = 0.003), obese individuals (OR = 2.31, 95% CI = 1.52-3.5, p = 0.0002, (p bonf = 0.0004)), patients with low fruit and vegetable intake (OR = 1.72, 95% CI = 1.15-2.58, p = 0.01, (p bonf = 0.02)), low physical activity (OR = 1.93, 95% CI = 1.26-2.94, p = 0.0035, (p bonf = 0.007)), and nonsmokers (OR = 1.65, 95% CI = 1.11-2.46, p = 0.02). This SNP correlated with increased BMI (p = 0.006) and worsened thrombodynamic parameters (maximum optical density of the formed clot, D (p = 0.02), delayed appearance of spontaneous clots, Tsp (p = 0.02), clot size 30 min after coagulation activation, CS (p = 0.036)). SNP rs17078346 SLC6A20-LZTFL1 was linked with increased BMI (p = 0.01) and severe COVID-19 in obese individuals (risk allele C, OR = 1.72, 95% CI = 1.15-2.58, p = 0.01, (p bonf = 0.02)). SNP rs12610495 DPP9 was associated with increased BMI (p = 0.01), severe COVID-19 in obese patients (risk allele G, OR = 1.48, 95% CI = 1.09-2.01, p = 0.01, (p bonf = 0.02)), and worsened thrombodynamic parameters (time to the start of clot growth, Tlag (p = 0.01)). For rs7949972 ELF5, a protective effect against severe COVID-19 was observed in non-obese patients (effect allele T, OR = 0.67, 95% CI = 0.47-0.95, p = 0.02, (p bonf = 0.04)), improving thrombodynamic parameters (CS (p = 0.02), stationary spatial clot growth rates, Vst (p = 0.02)). Finally, rs12585036 ATP11A exhibited a protective effect against severe COVID-19 in males (protective allele A, OR = 0.51, 95% CI = 0.32-0.83, p = 0.004). SNPs rs67579710 THBS3, THBS3-AS1, rs17713054 SLC6A20-LZTFL1, rs7949972 ELF5, rs9636867 IFNAR2-were involved in two or more of the most significant G×G interactions (p perm ≤ 0.01). The pairwise combination rs67579710 THBS3, THBS3-AS1 × rs17713054 SLC6A20-LZTFL1 was a priority in determining susceptibility to severe COVID-19 (it was included in four of the top five most significant SNP-SNP interaction models).

Conclusion

Overall, this study represents a comprehensive molecular-genetic and bioinformatics analysis of the involvement of GWAS-significant loci in the molecular mechanisms of severe COVID-19, gene-gene and gene-environmental interactions, and provides evidence of their relationship with thromboinflammation parameters in patients hospitalized in intensive care units.

Hypoxia-inducible factors in postnatal mouse molar dental pulp development: insights into expression patterns, localisation and metabolic pathways

Hypoxia is relevant to several physiological and pathological processes and this also applies for the tooth. The adaptive response to lowering oxygen concentration is mediated by hypoxia-inducible factors (HIFs). Since HIFs were shown to participate in the promotion of angiogenesis, stem cell survival, odontoblast differentiation and dentin formation, they may play a beneficial role in the tooth reparative processes. Although some data were generated in vitro, little is known about the in vivo context of HIFs in tooth development. In order to contribute to this field, the mouse mandibular first molar was used as a model.The expression and in situ localisation of HIFs were examined at postnatal (P) days P0, P7, P14, using RT-PCR and immunostaining. The expression pattern of a broad spectrum of hypoxia-related genes was monitored by customised PCR Arrays. Metabolic aspects were evaluated by determination of the lactate level and mRNA expression of the mitochondrial marker Nd1.The results show constant high mRNA expression of Hif1a, increasing expression of Hif2a, and very low expression of Hif3a during early postnatal molar development. In the examined period the localisation of HIFs in the nuclei of odontoblasts and the subodontoblastic layer identified their presence during odontoblastic differentiation. Additionally, the lower lactate level and higher expression of mitochondrial Nd1 in advanced development points to decreasing glycolysis during differentiation. Postnatal nuclear localisation of HIFs indicates a hypoxic state in specific areas of dental pulp as oxygen demands depend on physiological events such as crown and root dentin mineralization.

Natural Products in the Treatment of Retinopathy of Prematurity: Exploring Therapeutic Potentials

Retinopathy of prematurity (ROP) is a vascular disorder affecting the retinas of preterm infants. This condition arises when preterm infants in incubators are exposed to high oxygen levels, leading to oxidative stress, inflammatory responses, and a downregulation of vascular endothelial growth factors, which causes the loss of retinal microvascular capillaries. Upon returning to room air, the upregulation of vascular growth factors results in abnormal vascular growth of retinal endothelial cells. Without appropriate intervention, ROP can progress to blindness. The prevalence of ROP has risen, making it a significant cause of childhood blindness. Current treatments, such as laser therapy and various pharmacologic approaches, are limited by their potential for severe adverse effects. Therefore, a deeper understanding of ROP's pathophysiology and the development of innovative treatments are imperative. Natural products from plants, fungi, bacteria, and marine organisms have shown promise in treating various diseases and have gained attention in ROP research due to their minimal side effects and wide-ranging beneficial properties. This review discusses the roles and mechanisms of natural products that hold potential as therapeutic agents in ROP management.

Mechanism and rational combinations with GP-2250, a novel oxathiazine derivative, in ovarian cancer

BACKGROUND

GP-2250, a novel analog of taurultam (TRLT), has emerged as a potent anti-neoplastic drug; however, the mechanisms underlying its effects are not well understood. Here, we investigated the mechanism of action and the biological effects of GP-2250 using in vitro and in vivo models.

METHODS

We carried out a series of in vitro (MTT assay, Annexin V/PI assay, colony formation assay, reverse-phase protein array [RPPA], and HRLC/IC analysis) to determine the biological activity of GP-2250 and investigate the mechanism of action. In vivo experiments were carried out to determine the therapeutic efficacy of GP-2250 alone and in combination with standard-of-care drugs (e.g., paclitaxel, cisplatin, topotecan, and poly ADP-ribose polymerase [PARP] inhibitors).

RESULTS

We investigated the cytotoxic effect of GP-2250 in 10 ovarian cancer cell lines and found GP-2250 combined with a PARP inhibitor had the greatest synergy. RPPA revealed that GP-2250 inhibited hypoxia-inducible factor-1α, AKT, and mammalian target of rapamycin (mTOR) activation and expression. High-resolution mass spectrometry revealed that hexokinase2 activity and protein expression were significantly reduced by GP-2250 exposure. Furthermore, GP-2250 reduced glycolysis and ATP synthesis in cancer cells. An in vivo pharmacodynamic experiment using the OVCAR8 mouse model demonstrated that 500 mg/kg GP-2250 was effective in downregulating AKT and mTOR activation and expression. In the in vivo therapy experiment using an orthotopic mouse model, a combination of GP-2250 with either PARP inhibitors or bevacizumab showed a significant reduction of tumor weights and nodules compared to those treated with a vehicle, control IgG groups, or monotherapy groups.

CONCLUSIONS

Taken together, our data indicate that GP-2250 exerts profound effects on tumor metabolism and, in combination with PARP inhibitors or bevacizumab, showed promising anti-tumor efficacy. These findings could have implications for the clinical development of GP-2250.

Nucleic acid cancer vaccines targeting tumor related angiogenesis. Could mRNA vaccines constitute a game changer?

Tumor related angiogenesis is an attractive target in cancer therapeutic research due to its crucial role in tumor growth, invasion, and metastasis. Different agents were developed aiming to inhibit this process; however they had limited success. Cancer vaccines could be a promising tool in anti-cancer/anti-angiogenic therapy. Cancer vaccines aim to initiate an immune response against cancer cells upon presentation of tumor antigens which hopefully will result in the eradication of disease and prevention of its recurrence by inducing an efficient and long-lasting immune response. Different vaccine constructs have been developed to achieve this and they could include either protein-based or nucleic acid-based vaccines. Nucleic acid vaccines are simple and relatively easy to produce, with high efficiency and safety, thus prompting a high interest in the field. Different DNA vaccines have been developed to target crucial regulators of tumor angiogenesis. Most of them were successful in pre-clinical studies, mostly when used in combination with other therapeutics, but had limited success in the clinic. Apparently, different tumor evasion mechanisms and reduced immunogenicity still limit the potential of these vaccines and there is plenty of room for improvement. Nowadays, mRNA cancer vaccines are making remarkable progress due to improvements in the manufacturing technology and represent a powerful potential alternative. Apart from their efficiency, mRNA vaccines are simple and cheap to produce, can encompass multiple targets simultaneously, and can be quickly transferred from bench to bedside. mRNA vaccines have already accomplished amazing results in cancer clinical trials, thus ensuring a bright future in the field, although no anti-angiogenic mRNA vaccines have been described yet. This review aims to describe recent advances in anti-angiogenic DNA vaccine therapy and to provide perspectives for use of revolutionary approaches such are mRNA vaccines for anti-angiogenic treatments.

Sexual-biased necroinflammation is revealed as a predictor of bevacizumab benefit in glioblastoma

BACKGROUND

Glioblastoma (GBM) is a highly malignant brain tumor that affects men more often than women. In addition, the former shows a poorer survival prognosis. To date, the reason for this sex-specific aggressiveness remains unclear. Therefore, the aim of this study is to investigate tumor processes that explain these sex differences.

METHODS

This was a retrospective study of GBM patients which was stratified according to sex. A cohort with 73 tumors was analyzed with immunohistochemistry, RNA-seq and RT-qPCR to characterize differences in vascular and immunological profiles. Transcriptomic profiling, gene set enrichment analysis, and pathway enrichment analysis were used for discovering molecular pathways predominant in each group. We further investigated the therapeutic effect of bevacizumab (vascular endothelial growth factor A (VEGFA) blocking antibody) in a retrospective GBM cohort (36 tumors) based on sex differences.

RESULTS

We found that under hypoxic tumor conditions, 2 distinct tumor immuno-angiogenic ecosystems develop linked to sex differences and ESR1 expression is generated. One of these subgroups, which includes male patients with low ESR1 expression, is characterized by vascular fragility associated with the appearance of regions of necrosis and high inflammation (called necroinflamed tumors). This male-specific tumor subtype shows high inflammation related to myeloid-derived suppressor cells infiltration. Using this stratification, we identified a possible group of patients who could respond to bevacizumab (BVZ) and revealed a genetic signature that may find clinical applications as a predictor of those who may benefit most from this treatment.

CONCLUSIONS

This study provides a stratification based on the sexual differences in GBM, which associates the poor prognosis with the presence of immunosuppressive myeloid cells in the necrotic areas. This new stratification could change the current prognosis of GBM and identifies those who respond to BVZ treatment.

A gene for all seasons: The evolutionary consequences of HIF-1 in carcinogenesis, tumor growth and metastasis

Oxygen played a pivotal role in the evolution of multicellularity during the Cambrian Explosion. Not surprisingly, responses to fluctuating oxygen concentrations are integral to the evolution of cancer-a disease characterized by the breakdown of multicellularity. Poorly organized tumor vasculature results in chaotic patterns of blood flow characterized by large spatial and temporal variations in intra-tumoral oxygen concentrations. Hypoxia-inducible growth factor (HIF-1) plays a pivotal role in enabling cells to adapt, metabolize, and proliferate in low oxygen conditions. HIF-1 is often constitutively activated in cancers, underscoring its importance in cancer progression. Here, we argue that the phenotypic changes mediated by HIF-1, in addition to adapting the cancer cells to their local environment, also "pre-adapt" them for proliferation at distant, metastatic sites. HIF-1-mediated adaptations include a metabolic shift towards anaerobic respiration or glycolysis, activation of cell survival mechanisms like phenotypic plasticity and epigenetic reprogramming, and formation of tumor vasculature through angiogenesis. Hypoxia induced epigenetic reprogramming can trigger epithelial to mesenchymal transition in cancer cells-the first step in the metastatic cascade. Highly glycolytic cells facilitate local invasion by acidifying the tumor microenvironment. New blood vessels, formed due to angiogenesis, provide cancer cells a conduit to the circulatory system. Moreover, survival mechanisms acquired by cancer cells in the primary site allow them to remodel tissue at the metastatic site generating tumor promoting microenvironment. Thus, hypoxia in the primary tumor promoted adaptations conducive to all stages of the metastatic cascade from the initial escape entry into a blood vessel, intravascular survival, extravasation into distant tissues, and establishment of secondary tumors.

The link between impaired oxygen supply and cognitive decline in peripheral artery disease

Although peripheral artery disease (PAD) primarily affects large arteries outside the brain, PAD is also associated with elevated cerebral vulnerabilities, including greater risks for brain injury (such as stroke), cognitive decline and dementia. In the present review, we aim to evaluate recent literature and extract information on potential mechanisms linking PAD and consequences on the brain. Furthermore, we suggest novel therapeutic avenues to mitigate cognitive decline and reduce risk of brain injury in patients with PAD. Various interventions, notably exercise, directly or indirectly improve systemic blood flow and oxygen supply and are effective strategies in patients with PAD or cognitive decline. Moreover, triggering protective cellular and systemic mechanisms by modulating inspired oxygen concentrations are emerging as potential novel treatment strategies. While several genetic and pharmacological approaches to modulate adaptations to hypoxia showed promising results in preclinical models of PAD, no clear benefits have yet been clinically demonstrated. We argue that genetic/pharmacological regulation of the involved adaptive systems remains challenging but that therapeutic variation of inspired oxygen levels (e.g., hypoxia conditioning) are promising future interventions to mitigate associated cognitive decline in patients with PAD.

Wnt7a Decreases Brain Endothelial Barrier Function Via β-Catenin Activation

The blood-brain barrier consists of tightly connected endothelial cells protecting the brain's microenvironment from the periphery. These endothelial cells are characterized by specific tight junction proteins such as Claudin-5 and Occludin, forming the endothelial barrier. Disrupting these cells might lead to blood-brain barrier dysfunction. The Wnt/β-catenin signaling pathway can regulate the expression of these tight junction proteins and subsequent barrier permeability. The aim of this study was to investigate the in vitro effects of Wnt7a mediated β-catenin signaling on endothelial barrier integrity. Mouse brain endothelial cells, bEnd.3, were treated with recombinant Wnt7a protein or XAV939, a selective inhibitor of Wnt/β-catenin mediated transcription to modulate the Wnt signaling pathway. The involvement of Wnt/HIF1α signaling was investigated by inhibiting Hif1α signaling with Hif1α siRNA. Wnt7a stimulation led to activation and nuclear translocation of β-catenin, which was inhibited by XAV939. Wnt7a stimulation decreased Claudin-5 expression mediated by β-catenin and decreased endothelial barrier formation. Wnt7a increased Hif1α and Vegfa expression mediated by β-catenin. However, Hif1α signaling pathway did not regulate tight junction proteins Claudin-5 and Occludin. Our data suggest that Wnt7a stimulation leads to a decrease in tight junction proteins mediated by the nuclear translocation of β-catenin, which hampers proper endothelial barrier formation. This process might be crucial in initiating endothelial cell proliferation and angiogenesis. Although HIF1α did not modulate the expression of tight junction proteins, it might play a role in brain angiogenesis and underlie pathogenic mechanisms in Wnt/HIF1α signaling in diseases such as cerebral small vessel disease.

Unravelling the molecular interplay: SUMOylation, PML nuclear bodies and vascular cell activity in health and disease

In the seemingly well-researched field of vascular research, there are still many underestimated factors and molecular mechanisms. In recent years, SUMOylation has become increasingly important. SUMOylation is a post-translational modification in which small ubiquitin-related modifiers (SUMO) are covalently attached to target proteins. Sites where these SUMO modification processes take place in the cell nucleus are PML nuclear bodies (PML-NBs) - multiprotein complexes with their essential main component and organizer, the PML protein. PML and SUMO, either alone or as partners, influence a variety of cellular processes, including regulation of transcription, senescence, DNA damage response and defence against microorganisms, and are involved in innate immunity and inflammatory responses. They also play an important role in maintaining homeostasis in the vascular system and in pathological processes leading to the development and progression of cardiovascular diseases. This review summarizes information about the function of SUMO(ylation) and PML(-NBs) in the human vasculature from angiogenesis to disease and highlights their clinical potential as drug targets.

MEK inhibitors: a promising targeted therapy for cardiovascular disease

Cardiovascular disease (CVD) represents the leading cause of mortality and disability all over the world. Identifying new targeted therapeutic approaches has become a priority of biomedical research to improve patient outcomes and quality of life. The RAS-RAF-MEK (mitogen-activated protein kinase kinase)-ERK (extracellular signal-regulated kinase) pathway is gaining growing interest as a potential signaling cascade implicated in the pathogenesis of CVD. This pathway is pivotal in regulating cellular processes like proliferation, growth, migration, differentiation, and survival, which are vital in maintaining cardiovascular homeostasis. In addition, ERK signaling is involved in controlling angiogenesis, vascular tone, myocardial contractility, and oxidative stress. Dysregulation of this signaling cascade has been linked to cell dysfunction and vascular and cardiac pathological remodeling, which contribute to the onset and progression of CVD. Recent and ongoing research has provided insights into potential therapeutic interventions targeting the RAS-RAF-MEK-ERK pathway to improve cardiovascular pathologies. Preclinical studies have demonstrated the efficacy of targeted therapy with MEK inhibitors (MEKI) in attenuating ERK activation and mitigating CVD progression in animal models. In this article, we first describe how ERK signaling contributes to preserving cardiovascular health. We then summarize current knowledge of the roles played by ERK in the development and progression of cardiac and vascular disorders, including atherosclerosis, myocardial infarction, cardiac hypertrophy, heart failure, and aortic aneurysm. We finally report novel therapeutic strategies for these CVDs encompassing MEKI and discuss advantages, challenges, and future developments for MEKI therapeutics.

The Janus face of HIF-1α in ischemic stroke and the possible associated pathways

Stroke is the most devastating disease, causing paralysis and eventually death. Many clinical and experimental trials have been done in search of a new safe and efficient medicine; nevertheless, scientists have yet to discover successful remedies that are also free of adverse effects. This is owing to the variability in intensity, localization, medication routes, and each patient's immune system reaction. HIF-1α represents the modern tool employed to treat stroke diseases due to its functions: downstream genes such as glucose metabolism, angiogenesis, erythropoiesis, and cell survival. Its role can be achieved via two downstream EPO and VEGF strongly related to apoptosis and antioxidant processes. Recently, scientists paid more attention to drugs dealing with the HIF-1 pathway. This review focuses on medicines used for ischemia treatment and their potential HIF-1α pathways. Furthermore, we discussed the interaction between HIF-1α and other biological pathways such as oxidative stress; however, a spotlight has been focused on certain potential signalling contributed to the HIF-1α pathway. HIF-1α is an essential regulator of oxygen balance within cells which affects and controls the expression of thousands of genes related to sustaining homeostasis as oxygen levels fluctuate. HIF-1α's role in ischemic stroke strongly depends on the duration and severity of brain damage after onset. HIF-1α remains difficult to investigate, particularly in ischemic stroke, due to alterations in the acute and chronic phases of the disease, as well as discrepancies between the penumbra and ischemic core. This review emphasizes these contrasts and analyzes the future of this intriguing and demanding field.

Lung injury-induced activated endothelial cell states persist in aging-associated progressive fibrosis

Progressive lung fibrosis is associated with poorly understood aging-related endothelial cell dysfunction. To gain insight into endothelial cell alterations in lung fibrosis we performed single cell RNA-sequencing of bleomycin-injured lungs from young and aged mice. Analysis reveals activated cell states enriched for hypoxia, glycolysis and YAP/TAZ activity in ACKR1+ venous and TrkB+ capillary endothelial cells. Endothelial cell activation is prevalent in lungs of aged mice and can also be detected in human fibrotic lungs. Longitudinal single cell RNA-sequencing combined with lineage tracing demonstrate that endothelial activation resolves in young mouse lungs but persists in aged ones, indicating a failure of the aged vasculature to return to quiescence. Genes associated with activated lung endothelial cells states in vivo can be induced in vitro by activating YAP/TAZ. YAP/TAZ also cooperate with BDNF, a TrkB ligand that is reduced in fibrotic lungs, to promote capillary morphogenesis. These findings offer insights into aging-related lung endothelial cell dysfunction that may contribute to defective lung injury repair and persistent fibrosis.

β3-adREnoceptor Analysis in CORD Blood of Neonates (β3 RECORD): Study Protocol of a Pilot Clinical Investigation

Background and Objective: The embryo and the fetus develop in a physiologically hypoxic environment, where vascularization is sustained by HIF-1, VEGF, and the β-adrenergic system. In animals, β3-adrenoceptors (β3-ARs), up-regulated by hypoxia, favor global fetal wellness to such an extent that most diseases related to prematurity are hypothesized to be induced or aggravated by a precocious β3-AR down-regulation, due to premature exposure to a relatively hyperoxic environment. In animals, β3-AR pharmacological agonism is currently investigated as a possible new therapeutic opportunity to counteract oxygen-induced damages. Our goal is to translate the knowledge acquired in animals to humans. Recently, we have demonstrated that fetuses become progressively more hypoxemic from mid-gestation to near-term, but starting from the 33rd-34th week, oxygenation progressively increases until birth. The present paper aims to describe a clinical research protocol, evaluating whether the expression level of HIF-1, β3-ARs, and VEGF is modulated by oxygen during intrauterine and postnatal life, in a similar way to animals. Materials and Methods: In a prospective, non-profit, single-center observational study we will enroll 100 preterm (group A) and 100 full-term newborns (group B). We will collect cord blood samples (T0) and measure the RNA expression level of HIF-1, β3-ARs, and VEGF by digital PCR. In preterms, we will also measure gene expression at 48-72h (T1), 14 days (T2), and 30 days (T3) of life and at 40 ± 3 weeks of post-menstrual age (T4), regardless of the day of life. We will compare group A (T0) vs. group B (T0) and identify any correlations between the values obtained from serial samples in group A and the clinical data of the patients. Our protocol has been approved by the Pediatric Ethical Committee for Clinical Research of the Tuscany region (number 291/2022). Expected Results: The observation that in infants, the HIF-1/β3-ARs/VEGF axis shows similar modulation to that of animals could suggest that β3-ARs also promote fetal well-being in humans.

Loss of c-Kit in Endothelial Cells Protects against Hindlimb Ischemia

BACKGROUND

Critical limb ischemia (CLI) is the end stage of peripheral artery disease (PAD), and around 30% of CLI patients are ineligible for current treatments. The angiogenic benefits of c-Kit have been reported in the ischemia scenario; however, the present study demonstrates the effects of specific endothelial c-Kit signaling in arteriogenesis during hindlimb ischemia.

METHODS

We created conditional knockout mouse models that decrease c-Kit (c-Kit VE-Cadherin CreERT2-c-Kit) or its ligand (SCF VE-Cadherin CreERT2-SCF) specifically in endothelial cells (ECs) after tamoxifen treatment. These mice and a control group (wild-type VE-Cadherin CreERT2-WT) were subjected to hindlimb ischemia or aortic crush to evaluate perfusion/arteriogenesis and endothelial barrier permeability, respectively.

RESULTS

Our data confirmed the lower gene expression of c-Kit and SCF in the ECs of c-Kit and SCF mice, respectively. In addition, we confirmed the lower percentage of ECs positive for c-Kit in c-Kit mice. Further, we found that c-Kit and SCF mice had better limb perfusion and arteriogenesis compared to WT mice. We also demonstrated that c-Kit and SCF mice had a preserved endothelial barrier after aortic crush compared to WT.

CONCLUSIONS

Our data demonstrate the deleterious effects of endothelial SCF/c-Kit signaling on arteriogenesis and endothelial barrier integrity.

Affinity of PET-MRI Tracers for Hypoxic Cells in Breast Cancer: A Systematic Review

Tumour hypoxia is a known microenvironmental culprit for treatment resistance, tumour recurrence and promotion of metastatic spread. Despite the long-known existence of this factor within the tumour milieu, hypoxia is still one of the greatest challenges in cancer management. The transition from invasive and less reliable detection methods to more accurate and non-invasive ways to identify and quantify hypoxia was a long process that eventually led to the promising results showed by functional imaging techniques. Hybrid imaging, such as PET-CT, has the great advantage of combining the structural or anatomical image (offered by CT) with the functional or metabolic one (offered by PET). However, in the context of hypoxia, it is only the PET image taken after appropriate radiotracer administration that would supply hypoxia-specific information. To overcome this limitation, the development of the latest hybrid imaging systems, such as PET-MRI, enables a synergistic approach towards hypoxia imaging, with both methods having the potential to provide functional information on the tumour microenvironment. This study is designed as a systematic review of the literature on the newest developments of PET-MRI for the imaging of hypoxic cells in breast cancer. The analysis includes the affinity of various PET-MRI tracers for hypoxia in this patient group as well as the correlations between PET-specific and MRI-specific parameters, to offer a broader view on the potential for the widespread clinical implementation of this hybrid imaging technique.

Increase in Vascular Endothelial Growth Factor (VEGF) Expression and the Pathogenesis of iMCD-TAFRO

TAFRO (thrombocytopenia (T), anasarca (A), fever (F), reticulin fibrosis (F/R), renal failure (R), and organomegaly (O)) is a heterogeneous clinical subtype of idiopathic multicentric Castleman disease (iMCD) associated with a significantly poorer prognosis than other subtypes of iMCD. TAFRO symptomatology can also be seen in pathological contexts outside of iMCD, but it is unclear if those cases should be considered representative of a different disease entity or simply a severe presentation of other infectious, malignant, and rheumatological diseases. While interleukin-6 (IL-6) is an established driver of iMCD-TAFRO pathogenesis in a subset of patients, the etiology is unknown. Recent case reports and literature reviews on TAFRO patients suggest that vascular endothelial growth factor (VEGF), and the interplay of VEGF and IL-6 in concert, rather than IL-6 as a single cytokine, may be drivers for iMCD-TAFRO pathophysiology, especially renal injury. In this review, we discuss the possible role of VEGF in the pathophysiology and clinical manifestations of iMCD-TAFRO. In particular, VEGF may be involved in iMCD-TAFRO pathology through its ability to activate RAS/RAF/MEK/ERK and PI3K/AKT/mTOR signaling pathways. Further elucidating a role for the VEGF-IL-6 axis and additional disease drivers may shed light on therapeutic options for the treatment of TAFRO patients who do not respond to, or otherwise relapse following, treatment with IL-6 targeting drugs. This review investigates the potential role of VEGF in the pathophysiology of iMCD-TAFRO and the potential for targeting related signaling pathways in the future.

Mitochondrial metabolism regulation and epigenetics in hypoxia

The complex and dynamic interaction between cellular energy control and gene expression modulation is shown by the intersection between mitochondrial metabolism and epigenetics in hypoxic environments. Poor oxygen delivery to tissues, or hypoxia, is a basic physiological stressor that sets off a series of reactions in cells to adapt and endure oxygen-starved environments. Often called the "powerhouse of the cell," mitochondria are essential to cellular metabolism, especially regarding producing energy through oxidative phosphorylation. The cellular response to hypoxia entails a change in mitochondrial metabolism to improve survival, including epigenetic modifications that control gene expression without altering the underlying genome. By altering the expression of genes involved in angiogenesis, cell survival, and metabolism, these epigenetic modifications help cells adapt to hypoxia. The sophisticated interplay between mitochondrial metabolism and epigenetics in hypoxia is highlighted by several important points, which have been summarized in the current article. Deciphering the relationship between mitochondrial metabolism and epigenetics during hypoxia is essential to understanding the molecular processes that regulate cellular adaptation to reduced oxygen concentrations.

Intrathecal Fumagillin Alleviates Chronic Neuropathy-Induced Nociceptive Sensitization and Modulates Spinal Astrocyte-Neuronal Glycolytic and Angiogenic Proteins

Nociceptive sensitization is accompanied by the upregulation of glycolysis in the central nervous system in neuropathic pain. Growing evidence has demonstrated glycolysis and angiogenesis to be related to the inflammatory processes. This study investigated whether fumagillin inhibits neuropathic pain by regulating glycolysis and angiogenesis. Fumagillin was administered through an intrathecal catheter implanted in rats with chronic constriction injury (CCI) of the sciatic nerve. Nociceptive, behavioral, and immunohistochemical analyses were performed to evaluate the effects of the inhibition of spinal glycolysis-related enzymes and angiogenic factors on CCI-induced neuropathic pain. Fumagillin reduced CCI-induced thermal hyperalgesia and mechanical allodynia from postoperative days (POD) 7 to 14. The expression of angiogenic factors, vascular endothelial growth factor (VEGF) and angiopoietin 2 (ANG2), increased in the ipsilateral lumbar spinal cord dorsal horn (SCDH) following CCI. The glycolysis-related enzymes, pyruvate kinase M2 (PKM2) and lactate dehydrogenase A (LDHA) significantly increased in the ipsilateral lumbar SCDH following CCI on POD 7 and 14 compared to those in the control rats. Double immunofluorescence staining indicated that VEGF and PKM2 were predominantly expressed in the astrocytes, whereas ANG2 and LDHA were predominantly expressed in the neurons. Intrathecal infusion of fumagillin significantly reduced the expression of angiogenic factors and glycolytic enzymes upregulated by CCI. The expression of hypoxia-inducible factor-1α (HIF-1α), a crucial transcription factor that regulates angiogenesis and glycolysis, was also upregulated after CCI and inhibited by fumagillin. We concluded that intrathecal fumagillin may reduce the expression of ANG2 and LDHA in neurons and VEGF and PKM2 in the astrocytes of the SCDH, further attenuating spinal angiogenesis in neuropathy-induced nociceptive sensitization. Hence, fumagillin may play a role in the inhibition of peripheral neuropathy-induced neuropathic pain by modulating glycolysis and angiogenesis.

Roles of HIF-1α signaling in Mycobacterium tuberculosis infection: New targets for anti-TB therapeutics?

Tuberculosis (TB), a deadly infectious disease induced by Mycobacterium tuberculosis (Mtb), continues to be a global public health issue that kill millions of patents every year. Despite significant efforts have been paid to identify effective TB treatments, the emergence of drug-resistant strains of the disease and the presence of comorbidities in TB patients urges us to explore the detailed mechanisms involved in TB immunity and develop more effective innovative anti-TB strategies. HIF-1α, a protein involved in regulating cellular immune responses during TB infection, has been highlighted as a promising target for the development of novel strategies for TB treatment due to its critical roles in anti-TB host immunity. This review provides a summary of current research progress on the roles of HIF-1α in TB infection, highlighting its importance in regulating the host immune response upon Mtb infection and summarizing the influences and mechanisms of HIF-1α on anti-TB immunological responses of host cells. This review also discusses the various challenges associated with developing HIF-1α as a target for anti-TB therapies, including ensuring specificity and avoiding off-target effects on normal cell function, determining the regulation and expression of HIF-1α in TB patients, and developing drugs that can inhibit HIF-1α. More deep understanding of the molecular mechanisms involved in HIF-1α signaling, its impact on TB host status, and systematic animal testing and clinical trials may benefit the optimization of HIF-1α as a novel therapeutic target for TB.

Regulation of the HIF switch in human endothelial and cancer cells

Hypoxia-inducible factors (HIFs) are transcription factors that reprogram the transcriptome for cells to survive hypoxic insults and oxidative stress. They are important during embryonic development and reprogram the cells to utilize glycolysis when the oxygen levels are extremely low. This metabolic change facilitates normal cell survival as well as cancer cell survival. The key feature in survival is the transition between acute hypoxia and chronic hypoxia, and this is regulated by the transition between HIF-1 expression and HIF-2/HIF-3 expression. This transition is observed in many human cancers and endothelial cells and referred to as the HIF Switch. Here we discuss the mechanisms involved in the HIF Switch in human endothelial and cancer cells which include mRNA and protein levels of the alpha chains of the HIFs. A major continuing effort in this field is directed towards determining the differences between normal and tumor cell utilization of this important pathway, and how this could lead to potential therapeutic approaches.