Regulation of hypoxia-inducible factor 1alpha is mediated by an O2-dependent degradation domain via the ubiquitin-proteasome pathway

Paeonol prevents sepsis-associated encephalopathy via regulating the HIF1A pathway in microglia

Paeonol, a phenolic acid compound extracted from the Cortex Moutan, exhibits significant anti-inflammatory, antioxidant, and anti-apoptotic properties. This study aimed to investigate the effects of paeonol on neuroinflammation and depressive-like symptoms, and the underlying mechanisms in a mouse model of sepsis-associated encephalopathy (SAE) induced by lipopolysaccharide (LPS). To assess the therapeutic potential of paeonol in mice treated with LPS, behavioral assessments were conducted using the open-field test (OFT), tail suspension test (TST), and forced swimming test (FST), and quantitative PCR (qPCR), Western blot, and immunofluorescent staining were utilized to determine the expression levels of inflammatory molecules in the hippocampus in vivo and microglial cells in vitro. Our results revealed that paeonol significantly alleviated anxiety and depressive-like symptoms, as evidenced by improved activity in OFT, reduced immobility time in TST and FST, and decreased levels of inflammatory markers such as IL6, TNFα, and PFKFB3. Further in vitro experiments confirmed that paeonol downregulated the expression of pro-inflammatory molecules. A network pharmacology-based strategy combined with molecular docking and cellular thermal shift assay highlighted HIF1A as a potential target for paeonol. Similar anti-inflammatory effects of a HIF1A inhibitor were also observed in microglia treated with LPS. Furthermore, these effects were reversed by CoCl2, a HIF1A agonist, indicating the critical role of the HIF1A signaling pathway in mediating the therapeutic effects of paeonol. These findings highlight the potential of paeonol in modulating the HIF1A pathway, offering a promising therapeutic strategy for neuroinflammation in SAE.

Hypoxia-inducing transcription factors: architects of tumorigenesis and targets for anticancer drug discovery

Hypoxia-inducible factors (HIFs) play a pivotal role as master regulators of tumor survival and growth, controlling a wide array of cellular processes in response to hypoxic stress. Clinical data correlates upregulated HIF-1 and HIF-2 levels with an aggressive tumor phenotype and poor patient outcome. Despite extensive validation as a target in cancer, pharmaceutical targeting of HIFs, particularly the interaction between α and βsubunits that forms the active transcription factor, has proved challenging. Nonetheless, many indirect inhibitors of HIFs have been identified, targeting diverse parts of this pathway. Significant strides have also been made in the development of direct inhibitors of HIF-2, exemplified by the FDA approval of Belzutifan for the treatment of metastatic clear cell renal carcinoma. While efforts to target HIF-1 using various therapeutic modalities have shown promise, no clinical candidates have yet emerged. This review aims to provide insights into the intricate and extensive role played by HIFs in cancer, and the ongoing efforts to develop therapeutic agents against this target.

β2-integrins control HIF1α activation in human neutrophils

During inflammation, human neutrophils engage β2-integrins to migrate from the blood circulation to inflammatory sites with high cytokine but low oxygen concentrations. We tested the hypothesis that the inhibition of prolyl hydroxylase domain-containing enzymes (PHDs), cytokines, and β2-integrins cooperates in HIF pathway activation in neutrophils. Using either the PHD inhibitor roxadustat (ROX) (pseudohypoxia) or normobaric hypoxia to stabilize HIF, we observed HIF1α protein accumulation in adherent neutrophils. Several inflammatory mediators did not induce HIF1α protein but provided additive or even synergistic signals (e.g., GM-CSF) under pseudohypoxic and hypoxic conditions. Importantly, and in contrast to adherent neutrophils, HIF1α protein expression was not detected in strictly suspended neutrophils despite PHD enzyme inhibition and the presence of inflammatory mediators. Blocking β2-integrins in adherent and activating β2-integrins in suspension neutrophils established the indispensability of β2-integrins for increasing HIF1α protein. Using GM-CSF as an example, increased HIF1α mRNA transcription via JAK2-STAT3 was necessary but not sufficient for HIF1α protein upregulation. Importantly, we found that β2-integrins led to HIF1α mRNA translation through the phosphorylation of the essential translation initiation factors eIF4E and 4EBP1. Finally, pseudohypoxic and hypoxic conditions inducing HIF1α consistently delayed apoptosis in adherent neutrophils on fibronectin under low serum concentrations. Pharmacological HIF1α inhibition reversed delayed apoptosis, supporting the importance of this pathway for neutrophil survival under conditions mimicking extravascular sites. We describe a novel β2-integrin-controlled mechanism of HIF1α stabilization in human neutrophils. Conceivably, this mechanism restricts HIF1α activation in response to hypoxia and pharmacological PHD enzyme inhibitors to neutrophils migrating toward inflammatory sites.

ALKBH4 functions as a hypoxia-responsive tumor suppressor and inhibits metastasis and tumorigenesis

PURPOSE

The human AlkB homolog (ALKBH) dioxygenase superfamily plays a crucial role in gene regulation and is implicated in cancer progression. Under hypoxic conditions, hypoxia-inducible factors (HIFs) dynamically regulate methylation by controlling various dioxygenases, thereby modulating gene expression. However, the role of hypoxia-responsive AlkB dioxygenase remains unclear.

METHODS

The molecular events were examined using real-time PCR and Western blot analysis. Tumor cell aggressiveness was evaluated through migration, invasion, MTT, trypan blue exclusion, and colony formation assays. In vivo metastatic models and xenograft experiments were conducted to evaluate tumor progression.

RESULTS

Here, we examined the expression of the ALKBH superfamily under hypoxic conditions and found that ALKBH4 expression was negatively regulated by hypoxia. Knockdown of ALKBH4 enhanced the epithelial-mesenchymal transition (EMT), cell migration, invasion, and growth in vitro. The silencing of ALKBH4 enhanced metastatic ability and tumor growth in vivo. Conversely, overexpression of ALLKBH4 reversed these observations. Furthermore, overexpression of ALKBH4 significantly reversed hypoxia/HIF-1α-induced EMT, cell migration, invasion, tumor metastasis, and tumorigenicity. Notably, high expression of ALKBH4 was associated with better outcomes in head and neck cancer and breast cancer patients. Enrichment analysis also revealed that ALKBH4 was negatively enriched in hypoxia-related pathways. Clinically, a negative correlation between ALKBH4 and HIF-1α protein expression has been observed in tissues from both head and neck cancers and breast cancers.

CONCLUSION

These findings collectively suggest that ALKBH4 acts as a tumor suppressor and holds therapeutic potential for hypoxic tumors.

A nature-inspired HIF stabilizer derived from a highland-adaptation insertion of plateau pika Epas1 protein

Hypoxia-inducible factors (HIFs) play pivotal roles in numerous diseases and high-altitude adaptation, and HIF stabilizers have emerged as valuable therapeutic tools. In our prior investigation, we identified a highland-adaptation 24-amino-acid insertion within the Epas1 protein. This insertion enhances the protein stability of Epas1, and mice engineered with this insertion display enhanced resilience to hypoxic conditions. In the current study, we delved into the biochemical mechanisms underlying the protein-stabilizing effects of this insertion. Our findings unveiled that the last 11 amino acids within this insertion adopt a helical conformation and interact with the α-domain of the von Hippel-Lindau tumor suppressor protein (pVHL), thereby disrupting the Eloc-pVHL interaction and impeding the ubiquitination of Epas1. Utilizing a synthesized peptide, E14-24, we demonstrated its favorable membrane permeability and ability to stabilize endogenous HIF-α proteins, inducing the expression of hypoxia-responsive element (HRE) genes. Furthermore, the administration of E14-24 to mice subjected to hypoxic conditions mitigated body weight loss, suggesting its potential to enhance hypoxia adaptation.

Oxidative stress modulating nanomaterials and their biochemical roles in nanomedicine

Many pathological conditions are predominantly associated with oxidative stress, arising from reactive oxygen species (ROS); therefore, the modulation of redox activities has been a key strategy to restore normal tissue functions. Current approaches involve establishing a favorable cellular redox environment through the administration of therapeutic drugs and redox-active nanomaterials (RANs). In particular, RANs not only provide a stable and reliable means of therapeutic delivery but also possess the capacity to finely tune various interconnected components, including radicals, enzymes, proteins, transcription factors, and metabolites. Here, we discuss the roles that engineered RANs play in a spectrum of pathological conditions, such as cancer, neurodegenerative diseases, infections, and inflammation. We visualize the dual functions of RANs as both generator and scavenger of ROS, emphasizing their profound impact on diverse cellular functions. The focus of this review is solely on inorganic redox-active nanomaterials (inorganic RANs). Additionally, we deliberate on the challenges associated with current RANs-based approaches and propose potential research directions for their future clinical translation.

Homoharringtonine promotes non-small-cell lung cancer cell death via modulating HIF-1α/ERβ/E2F1 feedforward loop

OBJECTIVES

Hypoxia conditions promote the adaptation and progression of non-small-cell lung cancer (NSCLC) via hypoxia-inducible factors (HIF). HIF-1α may regulate estrogen receptor β (ERβ) and promote the progression of NSCLC. The phytochemical homoharringtonine (HHT) exerts strong inhibitory potency on NSCLC, with molecular mechanism under hypoxia being elusive.

METHODS

The effects of HHT on NSCLC growth were determined by cell viability assay, colony formation, flow cytometry, and H460 xenograft models. Western blotting, molecular docking program, site-directed mutagenesis assay, immunohistochemical assay, and immunofluorescence assay were performed to explore the underlying mechanisms of HHT-induced growth inhibition in NSCLC.

KEY FINDINGS

HIF-1α/ERβ signaling-related E2F1 is highly expressed and contributes to unfavorable survival and tumor growth. The findings in hypoxic cells, HIF-1α overexpressing cells, as well as ERβ- or E2F1-overexpressed and knockdown cells suggest that the HIF-1α/ERβ/E2F1 feedforward loop promotes NSCLC cell growth. HHT suppresses HIF-1α/ERβ/E2F1 signaling via the ubiquitin-proteasome pathway, which is dependent on the inhibition of the protein expression of HIF-1α and ERβ. Molecular docking and site-directed mutagenesis revealed that HHT binds to the GLU305 site of ERβ. HHT inhibits cell proliferation and colony formation and promotes apoptosis in both NSCLC cells and xenograft models.

CONCLUSION

The formation of the HIF-1α/ERβ/E2F1 feedforward loop promotes NSCLC growth and reveals a novel molecular mechanism by which HHT induces cell death in NSCLC.

Exposure to normobaric hypoxia shapes the acute inflammatory response in human whole blood cells in vivo

Cells of the immune defence, especially leukocytes, often have to perform their function in tissue areas that are characterized by oxygen deficiency, so-called hypoxia. Physiological hypoxia significantly affects leukocyte function and controls the innate and adaptive immune response mainly through transcriptional gene regulation via the hypoxia-inducible factors (HIFs). Multiple pathogens including components of bacteria, such as lipopolysaccharides (LPS) trigger the activation of leukocytes. HIF pathway activation enables immune cells to adapt to both hypoxic environments in physiological and inflammatory settings and modulates immune cell responses through metabolism changes and crosstalk with other immune-relevant signalling pathways. To study the mutual influence of both processes in vivo, we used a human endotoxemia model, challenging participants with an intravenous LPS injection post or prior to a 4-h stay in a hypoxic chamber with normobaric hypoxia of 10.5% oxygen. We analysed changes in gene expression in whole blood cells and determined inflammatory markers to unveil the crosstalk between both processes. Our investigations showed differentially altered gene expression patterns of HIF and target genes upon in vivo treatment with LPS and hypoxia. Further, we found evidence for effects of hypoxic priming upon inflammation in combination with immunomodulatory effects in whole blood cells in vivo. Our work elucidates the complex interplay of hypoxic and inflammatory HIF regulation in human immune cells and offers new perspectives for further clinical research.

Hypoxia inducible factor (HIF) 3α prevents COPD by inhibiting alveolar epithelial cell ferroptosis via the HIF-3α-GPx4 axis

Rationale: COPD patients are largely asymptomatic until the late stages when prognosis is generally poor. In this study, we shifted the focus to pre-COPD and smoking stages, and found enrichment of hypoxia inducible factor (HIF)-3α is in pre-COPD samples. Smoking induced regional tissue hypoxia and emphysema have been found in COPD patients. However, the mechanisms underlying hypoxia especially HIF-3α and COPD have not been investigated. Methods: We performed bulk-RNA sequencing on 36 peripheral lung tissue specimens from non-smokers, smokers, pre-COPD and COPD patients, and using "Mfuzz" algorithm to analysis the dataset dynamically. GSE171541 and EpCAM co-localization analyses were used to explore HIF-3α localization. Further, SftpcCreert2/+R26LSL-Hif3a knock-in mice and small molecular inhibitors in vitro were used to explore the involvement of HIF-3α in the pathophysiology of COPD. Results: Reactive oxygen species (ROS) and hypoxia were enriched in pre-COPD samples, and HIF-3α was downregulated in alveolar epithelial cells in COPD. In vitro experiments using lentivirus transfection, bulk-RNA seq, and RSL3 showed that the activation of the HIF-3α-GPx4 axis inhibited alveolar epithelial cell ferroptosis when treated with cigarettes smoking extracts (CSE). Further results from SftpcCreert2/+R26LSL-Hif3a knock-in mice demonstrated overexpression of HIF-3α inhibited alveolar epithelial cells ferroptosis and prevented the decline of lung function. Conclusion: Hypoxia and oxidation-related damage begins years before the onset of COPD symptoms, suggesting the imbalance and impairment of intracellular homeostatic system. The activation of the HIF-3α-GPx4 axis is a promising treatment target. By leveraging this comprehensive analysis method, more potential targets could be found and enhancing our understanding of the pathogenesis.

Cardiac programming in the placentally restricted sheep fetus in early gestation

Fetal growth restriction (FGR) occurs in 8% of human pregnancies, and the growth restricted newborn is at a greater risk of developing heart disease in later adult life. In sheep, experimental restriction of placental growth (PR) from conception results in FGR, a decrease in cardiomyocyte endowment and an upregulation of pathological hypertrophic signalling in the fetal heart in late gestation. However, there is no change in the expression of markers of cellular proliferation nor in the level of cardiomyocyte apoptosis in the heart of the PR fetus in late gestation. This suggests that FGR arises early in gestation and programs a decrease in cardiomyocyte endowment in early, rather than late, gestation. Here, control and PR fetal sheep were humanely killed at 55 days' gestation (term, 150 days). Fetal body and heart weight were lower in PR compared with control fetuses and there was evidence of sparing of fetal brain growth. While there was no change in the proportion of cardiomyocytes that were proliferating in the early gestation PR heart, there was an increase in measures of apoptosis, and markers of autophagy and pathological hypertrophy in the PR fetal heart. These changes in early gestation highlight that FGR is associated with evidence of early cell death and compensatory hypertrophic responses of cardiomyocytes in the fetal heart. The data suggest that early placental restriction results in a decrease in the pool of proliferative cardiomyocytes in early gestation, which would limit cardiomyocyte endowment in the heart of the PR fetus in late gestation. KEY POINTS: Placental restriction leading to fetal growth restriction (FGR) and chronic fetal hypoxaemia in sheep results in a decrease in cardiomyocyte endowment in late gestation. FGR did not change cardiomyocyte proliferation during early gestation but did result in increased apoptosis and markers of autophagy in the fetal heart, which may result in the decreased endowment of cardiomyocytes observed in late gestation. FGR in early gestation also results in increased hypoxia inducible factor signalling in the fetal heart, which in turn may result in the altered expression of epigenetic regulators, increased expression of insulin-like growth factor 2 and cardiomyocyte hypertrophy during late gestation and after birth.

Revisiting the role of hypoxia-inducible factors and nuclear factor erythroid 2-related factor 2 in regulating macrophage inflammation and metabolism

The recent birth of the immunometabolism field has comprehensively demonstrated how the rewiring of intracellular metabolism is critical for supporting the effector functions of many immune cell types, such as myeloid cells. Among all, the transcriptional regulation mediated by Hypoxia-Inducible Factors (HIFs) and Nuclear factor erythroid 2-related factor 2 (NRF2) have been consistently shown to play critical roles in regulating the glycolytic metabolism, redox homeostasis and inflammatory responses of macrophages (Mφs). Although both of these transcription factors were first discovered back in the 1990s, new advances in understanding their function and regulations have been continuously made in the context of immunometabolism. Therefore, this review attempts to summarize the traditionally and newly identified functions of these transcription factors, including their roles in orchestrating the key events that take place during glycolytic reprogramming in activated myeloid cells, as well as their roles in mediating Mφ inflammatory responses in various bacterial infection models.

Copper toxicity and deficiency: the vicious cycle at the core of protein aggregation in ALS

The pathophysiology of ALS involves many signs of a disruption in copper homeostasis, with both excess free levels and functional deficiency likely occurring simultaneously. This is crucial, as many important physiological functions are performed by cuproenzymes. While it is unsurprising that many ALS symptoms are related to signs of copper deficiency, resulting in vascular, antioxidant system and mitochondrial oxidative respiration deficiencies, there are also signs of copper toxicity such as ROS generation and enhanced protein aggregation. We discuss how copper also plays a key role in proteostasis and interacts either directly or indirectly with many of the key aggregate-prone proteins implicated in ALS, such as TDP-43, C9ORF72, SOD1 and FUS as well as the effect of their aggregation on copper homeostasis. We suggest that loss of cuproprotein function is at the core of ALS pathology, a condition that is driven by a combination of unbound copper and ROS that can either initiate and/or accelerate protein aggregation. This could trigger a positive feedback cycle whereby protein aggregates trigger the aggregation of other proteins in a chain reaction that eventually captures elements of the proteostatic mechanisms in place to counteract them. The end result is an abundance of aggregated non-functional cuproproteins and chaperones alongside depleted intracellular copper stores, resulting in a general lack of cuproenzyme function. We then discuss the possible aetiology of ALS and illustrate how strong risk factors including environmental toxins such as BMAA and heavy metals can functionally behave to promote protein aggregation and disturb copper metabolism that likely drives this vicious cycle in sporadic ALS. From this synthesis, we propose restoration of copper balance using copper delivery agents in combination with chaperones/chaperone mimetics, perhaps in conjunction with the neuroprotective amino acid serine, as a promising strategy in the treatment of this incurable disease.

Deleting the ribosomal prolyl hydroxylase OGFOD1 protects mice against diet-induced obesity and insulin resistance

Type 2 diabetes predisposes patients to heart disease, which is the primary cause of death across the globe. Type 2 diabetes often accompanies obesity and is defined by insulin resistance and abnormal glucose handling. Insulin resistance impairs glucose uptake and results in hyperglycemia, which damages tissues such as kidneys, liver, and heart. 2-oxoglutarate (2-OG)- and iron-dependent oxygenases (2-OGDOs), a family of enzymes regulating various aspects of cellular physiology, have been studied for their role in obesity and diet-induced insulin resistance. However, nothing is known of the 2-OGDO family member 2-oxoglutarate and iron-dependent prolyl hydroxylase domain containing protein 1 (OGFOD1) in this setting. OGFOD1 deletion leads to protection in cardiac ischemia-reperfusion injury and cardiac hypertrophy, which are two cardiac events that can lead to heart failure. Considering the remarkable correlation between heart disease and diabetes, the cardioprotection observed in OGFOD1-knockout mice led us to challenge these knockouts with high-fat diet. Wildtype mice fed a high-fat diet developed diet-induced obesity, insulin resistance, and glucose intolerance, but OGFOD1 knockout mice fed this same diet were resistant to diet-induced obesity and insulin resistance. These results support OGFOD1 down-regulation as a strategy for preventing obesity and insulin handling defects.

Cholesterol accumulation impairs HIF-1α-dependent immunometabolic reprogramming of LPS-stimulated macrophages by upregulating the NRF2 pathway

Lipid accumulation in macrophages (Mφs) is a hallmark of atherosclerosis. Yet, how lipid loading modulates Mφ inflammatory responses remains unclear. We endeavored to gain mechanistic insights into how pre-loading with free cholesterol modulates Mφ metabolism upon LPS-induced TLR4 signaling. We found that activities of prolyl hydroxylases (PHDs) and factor inhibiting HIF (FIH) are higher in cholesterol loaded Mφs post-LPS stimulation, resulting in impaired HIF-1α stability, transactivation capacity and glycolysis. In RAW264.7 cells expressing mutated HIF-1α proteins resistant to PHDs and FIH activities, cholesterol loading failed to suppress HIF-1α function. Cholesterol accumulation induced oxidative stress that enhanced NRF2 protein stability and triggered a NRF2-mediated antioxidative response prior to and in conjunction with LPS stimulation. LPS stimulation increased NRF2 mRNA and protein expression, but it did not enhance NRF2 protein stability further. NRF2 deficiency in Mφs alleviated the inhibitory effects of cholesterol loading on HIF-1α function. Mutated KEAP1 proteins defective in redox sensing expressed in RAW264.7 cells partially reversed the effects of cholesterol loading on NRF2 activation. Collectively, we showed that cholesterol accumulation in Mφs induces oxidative stress and NRF2 stabilization, which when combined with LPS-induced NRF2 expression leads to enhanced NRF2-mediated transcription that ultimately impairs HIF-1α-dependent glycolytic and inflammatory responses.

Regulation of Cancer-Associated miRNAs Expression under Hypoxic Conditions

Solid tumors frequently experience hypoxia or low O2 levels. In these conditions, hypoxia-inducible factor 1 alpha (HIF-1α) is activated and acts as a transcription factor that regulates cancer cell adaptation to O2 and nutrient deprivation. HIF-1α controls gene expression associated with various signaling pathways that promote cancer cell proliferation and survival. MicroRNAs (miRNAs) are 22-nucleotide noncoding RNAs that play a role in various biological processes essential for cancer progression. This review presents an overview of how hypoxia regulates the expression of multiple miRNAs in the progression of cancer cells.

Hypoxia-inducible factor in breast cancer: role and target for breast cancer treatment

Globally, breast cancer stands as the most prevalent form of cancer among women. The tumor microenvironment of breast cancer often exhibits hypoxia. Hypoxia-inducible factor 1-alpha, a transcription factor, is found to be overexpressed and activated in breast cancer, playing a pivotal role in the anoxic microenvironment by mediating a series of reactions. Hypoxia-inducible factor 1-alpha is involved in regulating downstream pathways and target genes, which are crucial in hypoxic conditions, including glycolysis, angiogenesis, and metastasis. These processes significantly contribute to breast cancer progression by managing cancer-related activities linked to tumor invasion, metastasis, immune evasion, and drug resistance, resulting in poor prognosis for patients. Consequently, there is a significant interest in Hypoxia-inducible factor 1-alpha as a potential target for cancer therapy. Presently, research on drugs targeting Hypoxia-inducible factor 1-alpha is predominantly in the preclinical phase, highlighting the need for an in-depth understanding of HIF-1α and its regulatory pathway. It is anticipated that the future will see the introduction of effective HIF-1α inhibitors into clinical trials, offering new hope for breast cancer patients. Therefore, this review focuses on the structure and function of HIF-1α, its role in advancing breast cancer, and strategies to combat HIF-1α-dependent drug resistance, underlining its therapeutic potential.

Sequestosome 1 (p62) mitigates hypoxia-induced cardiac dysfunction by stabilizing hypoxia-inducible factor 1α and nuclear factor erythroid 2-related factor 2

AIMS

Heart failure due to ischaemic heart disease (IHD) is a leading cause of mortality worldwide. A major contributing factor to IHD-induced cardiac damage is hypoxia. Sequestosome 1 (p62) is a multi-functional adaptor protein with pleiotropic roles in autophagy, proteostasis, inflammation, and cancer. Despite abundant expression in cardiomyocytes, the role of p62 in cardiac physiology is not well understood. We hypothesized that cardiomyocyte-specific p62 deletion evokes hypoxia-induced cardiac pathology by impairing hypoxia-inducible factor 1α (Hif-1α) and nuclear factor erythroid 2-related factor 2 (Nrf2) signalling.

METHODS AND RESULTS

Adult mice with germline deletion of cardiomyocyte p62 exhibited mild cardiac dysfunction under normoxic conditions. Transcriptomic analyses revealed a selective impairment in Nrf2 target genes in the hearts from these mice. Demonstrating the functional importance of this adaptor protein, adult mice with inducible depletion of cardiomyocyte p62 displayed hypoxia-induced contractile dysfunction, oxidative stress, and cell death. Mechanistically, p62-depleted hearts exhibit impaired Hif-1α and Nrf2 transcriptional activity. Because findings from these two murine models suggested a cardioprotective role for p62, mechanisms were evaluated using H9c2 cardiomyoblasts. Loss of p62 in H9c2 cells exposed to hypoxia reduced Hif-1α and Nrf2 protein levels. Further, the lack of p62 decreased Nrf2 protein expression, nuclear translocation, and transcriptional activity. Repressed Nrf2 activity associated with heightened Nrf2-Keap1 co-localization in p62-deficient cells, which was concurrent with increased Nrf2 ubiquitination facilitated by the E3 ligase Cullin 3, followed by proteasomal-mediated degradation. Substantiating our results, a gain of p62 in H9c2 cells stabilized Nrf2 and increased the transcriptional activity of Nrf2 downstream targets.

CONCLUSION

Cardiac p62 mitigates hypoxia-induced cardiac dysfunction by stabilizing Hif-1α and Nrf2.

Transcriptional elongation control of hypoxic response

The release of paused RNA polymerase II (RNAPII) from promoter-proximal regions is tightly controlled to ensure proper regulation of gene expression. The elongation factor PTEF-b is known to release paused RNAPII via phosphorylation of the RNAPII C-terminal domain by its cyclin-dependent kinase component, CDK9. However, the signal and stress-specific roles of the various RNAPII-associated macromolecular complexes containing PTEF-b/CDK9 are not yet clear. Here, we identify and characterize the CDK9 complex required for transcriptional response to hypoxia. Contrary to previous reports, our data indicate that a CDK9 complex containing BRD4 but not AFF1/4 is essential for this hypoxic stress response. We demonstrate that BRD4 bromodomains (BET) are dispensable for the release of paused RNAPII at hypoxia-activated genes and that BET inhibition by JQ1 is insufficient to impair hypoxic gene response. Mechanistically, we demonstrate that the C-terminal region of BRD4 is required for Polymerase-Associated Factor-1 Complex (PAF1C) recruitment to establish an elongation-competent RNAPII complex at hypoxia-responsive genes. PAF1C disruption using a small-molecule inhibitor (iPAF1C) impairs hypoxia-induced, BRD4-mediated RNAPII release. Together, our results provide insight into potentially targetable mechanisms that control the hypoxia-responsive transcriptional elongation.

Tumor targeted alpha particle therapy with an actinium-225 labelled antibody for carbonic anhydrase IX

Selective antibody targeted delivery of α particle emitting actinium-225 to tumors has significant therapeutic potential. This work highlights the design and synthesis of a new bifunctional macrocyclic diazacrown ether chelator, H2MacropaSqOEt, that can be conjugated to antibodies and forms stable complexes with actinium-225. The macrocyclic diazacrown ether chelator incorporates a linker comprised of a short polyethylene glycol fragment and a squaramide ester that allows selective reaction with lysine residues on antibodies to form stable vinylogous amide linkages. This new H2MacropaSqOEt chelator was used to modify a monoclonal antibody, girentuximab (hG250), that binds to carbonic anhydrase IX, an enzyme that is overexpressed on the surface of cancers such as clear cell renal cell carcinoma. This new antibody conjugate (H2MacropaSq-hG250) had an average chelator to antibody ratio of 4 : 1 and retained high affinity for carbonic anhydrase IX. H2MacropaSq-hG250 was radiolabeled quantitatively with [225Ac]AcIII within one minute at room temperature with micromolar concentrations of antibody and the radioactive complex is stable in human serum for >7 days. Evaluation of [225Ac]Ac(MacropaSq-hG250) in a mouse xenograft model, that overexpresses carbonic anhydrase IX, demonstrated a highly significant therapeutic response. It is likely that H2MacropaSqOEt could be used to modify other antibodies providing a readily adaptable platform for other actinium-225 based therapeutics.

Hypoxia-inducible factor induces cysteine dioxygenase and promotes cysteine homeostasis in Caenorhabditis elegans

Dedicated genetic pathways regulate cysteine homeostasis. For example, high levels of cysteine activate cysteine dioxygenase, a key enzyme in cysteine catabolism in most animal and many fungal species. The mechanism by which cysteine dioxygenase is regulated is largely unknown. In an unbiased genetic screen for mutations that activate cysteine dioxygenase (cdo-1) in the nematode Caenorhabditis elegans, we isolated loss-of-function mutations in rhy-1 and egl-9, which encode proteins that negatively regulate the stability or activity of the oxygen-sensing hypoxia inducible transcription factor (hif-1). EGL-9 and HIF-1 are core members of the conserved eukaryotic hypoxia response. However, we demonstrate that the mechanism of HIF-1-mediated induction of cdo-1 is largely independent of EGL-9 prolyl hydroxylase activity and the von Hippel-Lindau E3 ubiquitin ligase, the classical hypoxia signaling pathway components. We demonstrate that C. elegans cdo-1 is transcriptionally activated by high levels of cysteine and hif-1. hif-1-dependent activation of cdo-1 occurs downstream of an H2S-sensing pathway that includes rhy-1, cysl-1, and egl-9. cdo-1 transcription is primarily activated in the hypodermis where it is also sufficient to drive sulfur amino acid metabolism. Thus, the regulation of cdo-1 by hif-1 reveals a negative feedback loop that maintains cysteine homeostasis. High levels of cysteine stimulate the production of an H2S signal. H2S then acts through the rhy-1/cysl-1/egl-9 signaling pathway to increase HIF-1-mediated transcription of cdo-1, promoting degradation of cysteine via CDO-1.

Chemical Hypoxia Induces Pyroptosis in Neuronal Cells by Caspase-Dependent Gasdermin Activation

Hypoxia-induced neuronal death is a major cause of neurodegenerative diseases. Pyroptosis is a type of inflammatory programmed cell death mediated by elevated intracellular levels of reactive oxygen species (ROS). Therefore, we hypothesized that hypoxia-induced ROS may trigger pyroptosis via caspase-dependent gasdermin (GSDM) activation in neuronal cells. To test this, we exposed SH-SY5Y neuronal cells to cobalt chloride (CoCl2) to trigger hypoxia and then evaluated the cellular and molecular responses to hypoxic conditions. Our data revealed that CoCl2 induced cell growth inhibition and the expression of hypoxia-inducible factor-1α in SH-SY5Y cells. Exposure to CoCl2 elicits excessive accumulation of cytosolic and mitochondrial ROS in SH-SY5Y cells. CoCl2-induced hypoxia not only activated the intrinsic (caspases-3, -7, and -9) apoptotic pathway but also induced caspase-3/GSDME-dependent and NLRP3/caspase-1/GSDMD-mediated pyroptosis in SH-SY5Y cells. Importantly, inhibition of caspase-3 and -1 using selective inhibitors ameliorated pyroptotic cell death and downregulated GSDM protein expression. Additionally, treatment with a ROS scavenger significantly suppressed caspase- and pyroptosis-related proteins in CoCl2-treated SH-SY5Y cells. Our findings indicate that hypoxia-mediated ROS production plays an important role in the activation of both apoptosis and pyroptosis in SH-SY5Y neuronal cells, thus providing a potential therapeutic strategy for hypoxia-related neurological diseases.

HIF-1α: A potential therapeutic opportunity in renal fibrosis

Renal fibrosis is a common outcome of various renal injuries, leading to structural destruction and functional decline of the kidney, and is also a critical prognostic indicator and determinant in renal diseases therapy. Hypoxia is induced in different stress and injuries in kidney, and the hypoxia inducible factors (HIFs) are activated in the context of hypoxia in response and regulation the hypoxia in time. Under stress and hypoxia conditions, HIF-1α increases rapidly and regulates intracellular energy metabolism, cell proliferation, apoptosis, and inflammation. Through reprogramming cellular metabolism, HIF-1α can directly or indirectly induce abnormal accumulation of metabolites, changes in cellular epigenetic modifications, and activation of fibrotic signals. HIF-1α protein expression and activity are regulated by various posttranslational modifications. The drugs targeting HIF-1α can regulate the downstream cascade signals by inhibiting HIF-1α activity or promoting its degradation. As the renal fibrosis is affected by renal diseases, different diseases may trigger different mechanisms which will affect the therapy effect. Therefore, comprehensive analysis of the role and contribution of HIF-1α in occurrence and progression of renal fibrosis, and determination the appropriate intervention time of HIF-1α in the process of renal fibrosis are important ideas to explore effective treatment strategies. This study reviews the regulation of HIF-1α and its mediated complex cascade reactions in renal fibrosis, and lists some drugs targeting HIF-1α that used in preclinical studies, to provide new insight for the study of the renal fibrosis mechanism.

Adipose Tissue Hypoxia in Obesity: Clinical Reappraisal of Hypoxia Hypothesis

Obese subjects exhibit lower adipose tissue oxygen consumption in accordance with the lower adipose tissue blood flow. Thereby, compared to lean subjects, obese individuals have almost half lower capillary density and more than half lower vascular endothelial growth factor (VEGF). The VEGF expression together with hypoxia-inducible transcription factor-1 alpha (HIF-1α) activity also requires phosphatidylinositol 3-kinase (PI3K) and mammalian target of rapamycin (mTOR)-mediated signaling. Especially HIF-1α is an important signaling molecule for hypoxia to induce the inflammatory responses. Hypoxia contributes to several biological functions, such as angiogenesis, cell proliferation, apoptosis, inflammation, and insulin resistance (IR). Pathogenesis of obesity-related comorbidities is attributed to intermittent hypoxia (IH), which is mostly observed in visceral obesity. Proinflammatory phenotype of the adipose tissue is a crucial link between IH and the development of IR. Inhibition of adaptive unfolded protein response (UPR) in hypoxia increases β cell death. Moreover, deletion of HIF-1α worsens β cell function. Oxidative stress, as well as the release of proinflammatory cytokines/adipokines in obesity, is proportional to the severity of IH. Reactive oxygen species (ROS) generation at mitochondria is responsible for propagation of the hypoxic signal; however, mitochondrial ROS production is required for hypoxic HIF-1α protein stabilization. Alterations in oxygen availability of adipose tissue directly affect the macrophage polarization and are responsible for the dysregulated adipocytokines production in obesity. Hypoxia both inhibits adipocyte differentiation from preadipocytes and macrophage migration from the hypoxic adipose tissue. Upon reaching a hypertrophic threshold beyond the adipocyte fat loading capacity, excess extracellular matrix (ECM) components are deposited, causing fibrosis. HIF-1α initiates the whole pathological process of fibrosis and inflammation in the obese adipose tissue. In addition to stressed adipocytes, hypoxia contributes to immune cell migration and activation which further aggravates adipose tissue fibrosis. Therefore, targeting HIF-1α might be an efficient way to suppress hypoxia-induced pathological changes in the ECM. The fibrosis score of adipose tissue correlates negatively with the body mass index and metabolic parameters. Inducers of browning/beiging adipocytes and adipokines, as well as modulations of matrix remodeling enzyme inhibitors, and associated gene regulators, are potential pharmacological targets for treating obesity.

HIF-1α signaling: Essential roles in tumorigenesis and implications in targeted therapies

The hypoxic microenvironment is an essential characteristic of most malignant tumors. Notably, hypoxia-inducible factor-1 alpha (HIF-1α) is a key regulatory factor of cellular adaptation to hypoxia, and many critical pathways are correlated with the biological activity of organisms via HIF-1α. In the intra-tumoral hypoxic environment, HIF-1α is highly expressed and contributes to the malignant progression of tumors, which in turn results in a poor prognosis in patients. Recently, it has been indicated that HIF-1α involves in various critical processes of life events and tumor development via regulating the expression of HIF-1α target genes, such as cell proliferation and apoptosis, angiogenesis, glucose metabolism, immune response, therapeutic resistance, etc. Apart from solid tumors, accumulating evidence has revealed that HIF-1α is also closely associated with the development and progression of hematological malignancies, such as leukemia, lymphoma, and multiple myeloma. Targeted inhibition of HIF-1α can facilitate an increased sensitivity of patients with malignancies to relevant therapeutic agents. In the review, we elaborated on the basic structure and biological functions of HIF-1α and summarized their current role in various malignancies. It is expected that they will have future potential for targeted therapy.

Insights into the complex interactions between Rab22a and extracellular vesicles in cancers

INTRODUCTION

Oncogenic Ras-related GTP-binding proteins, referred to as Rabs, are characterized by their intricate interactions with upstream, downstream molecules, and notably, extracellular vesicles (EVs). While the expansive family of Rabs and their associated signaling pathways have been exhaustively dissected, Rab22a emerges as an entity of outstanding interest, owing to its potent influence in many biological processes and its conspicuous correlation with cancer metastasis and migration. A burgeoning interest in the interactions between Rab22a and EVs in the field of oncology underscores the necessity for more in-depth reviews and scholarly discourses.

METHODS

We performed a review based on published original and review articles related to Rab22a, tumor, microRNA, exosome, microvesicles, EVs, CD147, lysosome, degradation, endosomal recycling, etc. from PubMed, Web of Science and Google Scholar databases.

RESULTS AND CONCLUSIONS

We summarize the regulatory processes governing the expression of Rab22a and the mutants of Rab22a. Notably, the present understanding of complex interactions between Rab22a and EVs are highlighted, encompassing both the impact of Rab22a on the genesis of EVs and the role of EVs that are affected by Rab22a mutants in propelling tumor advancement. The dynamic interaction between Rab22a and EVs plays a significant role in the progression of tumors, and it can provide novel insights into the pathogenesis of cancers and the development of new therapeutic targets.

Detection of Hypoxia in 2D and 3D Cell Culture Systems Using Genetically Encoded Fluorescent Hypoxia Sensors

In vivo oxygen availability varies widely between cellular microenvironments, depending on the tissue of origin and its cellular niche. It has long been known that too high or too low oxygen concentrations can act as a biological stressor. Thus, the precise control of oxygen availability should be a consideration for cell culture optimization, especially in the field of three-dimensional (3D) cell culture. In this chapter, we describe a system for visualizing oxygen limitations at a cellular level using human adipose tissue-derived mesenchymal stem cells (hAD-MSCs) that were genetically modified to express a fluorescent hypoxia sensor. This sensor can detect the activation of hypoxia-induced factors (HIF) transcription factors that lead to the expression of the oxygen-independent fluorescent protein, UnaG, at low oxygen concentrations. The response of these hypoxia reporter cells can be evaluated in two-dimensional (2D) and 3D cultivation platforms during exposure to hypoxia (1% O2) and normoxia (21% O2) using fluorescence microscopy and flow cytometry. We show that hypoxia reporter MSCs exhibit a hypoxia-induced fluorescence signal in both 2D and 3D cultivation platforms with fast decay kinetics after reoxygenation, rendering it a valuable tool for studying the cellular microenvironment and regenerative potential of hAD-MSCs in an in vivo-like setting.

Identification of Small Molecule Inhibitors and Ligand Directed Degraders of Calcium/Calmodulin Dependent Protein Kinase Kinase 1 and 2 (CaMKK1/2)

CaMKK2 signals through AMPK-dependent and AMPK-independent pathways to trigger cellular outputs including proliferation, differentiation, and migration, resulting in changes to metabolism, bone mass accrual, neuronal function, hematopoiesis, and immunity. CAMKK2 is upregulated in tumors including hepatocellular carcinoma, prostate, breast, and gastric cancer, and genetic deletion in myeloid cells results in increased antitumor immunity in several syngeneic models. Validation of the biological roles of CaMKK2 has relied on genetic deletion or small molecule inhibitors with activity against several biological targets. We sought to generate selective inhibitors and degraders to understand the biological impact of inhibiting catalytic activity and scaffolding and the potential therapeutic benefits of targeting CaMKK2. We report herein selective, ligand-efficient inhibitors and ligand-directed degraders of CaMKK2 that were used to probe immune and tumor intrinsic biology. These molecules provide two distinct strategies for ablating CaMKK2 signaling in vitro and in vivo.

Hypoxia and HIF-1α promote lytic de novo KSHV infection

IMPORTANCE

The current view is that the default pathway of Kaposi's sarcoma-associated herpesvirus (KSHV) infection is the establishment of latency, which is a prerequisite for lifelong infection and viral oncogenesis. This view about KSHV infection is supported by the observations that KSHV latently infects most of the cell lines cultured in vitro in the absence of any environmental stresses that may occur in vivo. The goal of this study was to determine the effect of hypoxia, a natural stress stimulus, on primary KSHV infection. Our data indicate that hypoxia promotes euchromatin formation on the KSHV genome following infection and supports lytic de novo KSHV infection. We also discovered that hypoxia-inducible factor-1α is required and sufficient for allowing lytic KSHV infection. Based on our results, we propose that hypoxia promotes lytic de novo infection in cells that otherwise support latent infection under normoxia; that is, the environmental conditions can determine the outcome of KSHV primary infection.

Oxidized Low-Density Lipoprotein Accumulation Suppresses Glycolysis and Attenuates the Macrophage Inflammatory Response by Diverting Transcription from the HIF-1α to the Nrf2 Pathway

Lipid accumulation in macrophages (Mφs) is a hallmark of atherosclerosis, yet how lipid accumulation affects inflammatory responses through rewiring of Mφ metabolism is poorly understood. We modeled lipid accumulation in cultured wild-type mouse thioglycolate-elicited peritoneal Mφs and bone marrow-derived Mφs with conditional (Lyz2-Cre) or complete genetic deficiency of Vhl, Hif1a, Nos2, and Nfe2l2. Transfection studies employed RAW264.7 cells. Mφs were cultured for 24 h with oxidized low-density lipoprotein (oxLDL) or cholesterol and then were stimulated with LPS. Transcriptomics revealed that oxLDL accumulation in Mφs downregulated inflammatory, hypoxia, and cholesterol metabolism pathways, whereas the antioxidant pathway, fatty acid oxidation, and ABC family proteins were upregulated. Metabolomics and extracellular metabolic flux assays showed that oxLDL accumulation suppressed LPS-induced glycolysis. Intracellular lipid accumulation in Mφs impaired LPS-induced inflammation by reducing both hypoxia-inducible factor 1-α (HIF-1α) stability and transactivation capacity; thus, the phenotype was not rescued in Vhl-/- Mφs. Intracellular lipid accumulation in Mφs also enhanced LPS-induced NF erythroid 2-related factor 2 (Nrf2)-mediated antioxidative defense that destabilizes HIF-1α, and Nrf2-deficient Mφs resisted the inhibitory effects of lipid accumulation on glycolysis and inflammatory gene expression. Furthermore, oxLDL shifted NADPH consumption from HIF-1α- to Nrf2-regulated apoenzymes. Thus, we postulate that repurposing NADPH consumption from HIF-1α to Nrf2 transcriptional pathways is critical in modulating inflammatory responses in Mφs with accumulated intracellular lipid. The relevance of our in vitro models was established by comparative transcriptomic analyses, which revealed that Mφs cultured with oxLDL and stimulated with LPS shared similar inflammatory and metabolic profiles with foamy Mφs derived from the atherosclerotic mouse and human aorta.

Interplay between lncRNA RP11-367G18.1 variant 2 and YY1 plays a vital role in hypoxia-mediated gene expression and tumorigenesis

BACKGROUND

The hypoxia-responsive long non-coding RNA, RP11-367G18.1, has recently been reported to induce histone 4 lysine 16 acetylation (H4K16Ac) through its variant 2; however, the underlying molecular mechanism remains poorly understood.

METHODS

RNA pull-down assay and liquid chromatography-tandem mass spectrometry were performed to identify RP11-367G18.1 variant 2-binding partner. The molecular events were examined utilizing western blot analysis, real-time PCR, luciferase reporter assay, chromatin immunoprecipitation, and chromatin isolation by RNA purification assays. The migration, invasion, soft agar colony formation, and in vivo xenograft experiments were conducted to evaluate the impact of RP11-367G18.1 variant 2-YY1 complex on tumor progression.

RESULTS

In this study, RNA sequencing data revealed that hypoxia and RP11-367G18.1 variant 2 co-regulated genes were enriched in tumor-related pathways. YY1 was identified as an RP11-367G18.1 variant 2-binding partner that activates the H4K16Ac mark. YY1 was upregulated under hypoxic conditions and served as a target gene for hypoxia-inducible factor-1α. RP11-367G18.1 variant 2 colocalized with YY1 and H4K16Ac in the nucleus under hypoxic conditions. Head and neck cancer tissues had higher levels of RP11-367G18.1 and YY1 which were associated with poor patient outcomes. RP11-367G18.1 variant 2-YY1 complex contributes to hypoxia-induced epithelial-mesenchymal transition, cell migration, invasion, and tumorigenicity. YY1 regulated hypoxia-induced genes dependent on RP11-367G18.1 variant 2.

CONCLUSIONS

RP11-367G18.1 variant 2-YY1 complex mediates the tumor-promoting effects of hypoxia, suggesting that this complex can be targeted as a novel therapeutic strategy for cancer treatment.

Boron in cancer therapeutics: An overview

Boron has become a crucial weapon in anticancer research due to its significant intervention in cell proliferation. Being an excellent bio-isosteric replacement of carbon, it has modulated the anticancer efficacy of various molecules in the development pipeline. It has elicited promising results through interactions with various therapeutic targets such as HIF-1α, steroid sulfatase, arginase, proteasome, etc. Since boron liberates alpha particles, it has a wide-scale application in Boron Neutron Capture therapy (BNCT), a radiotherapy that demonstrates selectivity towards cancer cells due to high boron uptake capacity. Significant advances in the medicinal chemistry of boronated compounds, such as boronated sugars, natural/unnatural amino acids, boronated DNA binders, etc., have been reported over the past few years as BNCT agents. In addition, boronated nanoparticles have assisted the field of bio-nano medicines by their usage in radiotherapy. This review exclusively focuses on the medicinal chemistry aspects, radiotherapeutic, and chemotherapeutic aspects of boron in cancer therapeutics. Emphasis is also given on the mechanism of action along with advantages over conventional therapies.

Hypoxia-inducible factor induces cysteine dioxygenase and promotes cysteine homeostasis in Caenorhabditis elegans

Dedicated genetic pathways regulate cysteine homeostasis. For example, high levels of cysteine activate cysteine dioxygenase, a key enzyme in cysteine catabolism in most animal and many fungal species. The mechanism by which cysteine dioxygenase is regulated is largely unknown. In an unbiased genetic screen for mutations that activate cysteine dioxygenase (cdo-1) in the nematode C. elegans, we isolated loss-of-function mutations in rhy-1 and egl-9, which encode proteins that negatively regulate the stability or activity of the oxygen-sensing hypoxia inducible transcription factor (hif-1). EGL-9 and HIF-1 are core members of the conserved eukaryotic hypoxia response. However, we demonstrate that the mechanism of HIF-1-mediated induction of cdo-1 is largely independent of EGL-9 prolyl hydroxylase activity and the von Hippel-Lindau E3 ubiquitin ligase, the classical hypoxia signaling pathway components. We demonstrate that C. elegans cdo-1 is transcriptionally activated by high levels of cysteine and hif-1. hif-1-dependent activation of cdo-1 occurs downstream of an H2S-sensing pathway that includes rhy-1, cysl-1, and egl-9. cdo-1 transcription is primarily activated in the hypodermis where it is also sufficient to drive sulfur amino acid metabolism. Thus, the regulation of cdo-1 by hif-1 reveals a negative feedback loop that maintains cysteine homeostasis. High levels of cysteine stimulate the production of an H2S signal. H2S then acts through the rhy-1/cysl-1/egl-9 signaling pathway to increase HIF-1-mediated transcription of cdo-1, promoting degradation of cysteine via CDO-1.

Hypoxia and renal fibrosis

Renal fibrosis is the final stage of most progressive kidney diseases. Chronic kidney disease (CKD) is associated with high comorbidity and mortality. Thus, preventing fibrosis and thereby preserving kidney function increases the quality of life and prolongs the survival of patients with CKD. Many processes such as inflammation or metabolic stress modulate the progression of kidney fibrosis. Hypoxia has also been implicated in the pathogenesis of renal fibrosis, and oxygen sensing in the kidney is of outstanding importance for the body. The dysregulation of oxygen sensing in the diseased kidney is best exemplified by the loss of stimulation of erythropoietin production from interstitial cells in the fibrotic kidney despite anemia. Furthermore, hypoxia is present in acute or chronic kidney diseases and may affect all cell types present in the kidney including tubular and glomerular cells as well as resident immune cells. Pro- and antifibrotic effects of the transcription factors hypoxia-inducible factors 1 and 2 have been described in a plethora of animal models of acute and chronic kidney diseases, but recent advances in sequencing technologies now allow for novel and deeper insights into the role of hypoxia and its cell type-specific effects on the progression of renal fibrosis, especially in humans. Here, we review existing literature on how hypoxia impacts the development and progression of renal fibrosis.

Karyopherins in the Remodeling of Extracellular Matrix: Implications in Tendon Injury

Rotator Cuff Tendinopathies (RCT) are debilitating conditions characterized by alterations in the extracellular matrix (ECM) of the shoulder tendon, resulting in pain, discomfort, and functional limitations. Specific mediators, including HIF-1α, TGF-β, MMP-9 and others have been implicated in the morphological changes observed in the tendon ECM. These mediators rely on karyopherins, a family of nuclear proteins involved in nucleo-cytoplasmic transport; however, the role of karyopherins in RCT remains understudied despite their potential role in nuclear transport mechanisms. Also, the understanding regarding the precise contributions of karyopherins in RCT holds great promise for deciphering the underlying pathophysiological mechanisms of the disease and potentially fostering the development of targeted therapeutic strategies. This article critically discusses the implications, possibilities, and perspectives of karyopherins in the pathophysiology of RCT.

Mitochondrial Factors in the Cell Nucleus

The origin of eukaryotic organisms involved the integration of mitochondria into the ancestor cell, with a massive gene transfer from the original proteobacterium to the host nucleus. Thus, mitochondrial performance relies on a mosaic of nuclear gene products from a variety of genomes. The concerted regulation of their synthesis is necessary for metabolic housekeeping and stress response. This governance involves crosstalk between mitochondrial, cytoplasmic, and nuclear factors. While anterograde and retrograde regulation preserve mitochondrial homeostasis, the mitochondria can modulate a wide set of nuclear genes in response to an extensive variety of conditions, whose response mechanisms often merge. In this review, we summarise how mitochondrial metabolites and proteins-encoded either in the nucleus or in the organelle-target the cell nucleus and exert different actions modulating gene expression and the chromatin state, or even causing DNA fragmentation in response to common stress conditions, such as hypoxia, oxidative stress, unfolded protein stress, and DNA damage.

Intracellular energy production and distribution in hypoxia

The hydrolysis of ATP is the primary source of metabolic energy for eukaryotic cells. Under physiological conditions, cells generally produce more than sufficient levels of ATP to fuel the active biological processes necessary to maintain homeostasis. However, mechanisms underpinning the distribution of ATP to subcellular microenvironments with high local demand remain poorly understood. Intracellular distribution of ATP in normal physiological conditions has been proposed to rely on passive diffusion across concentration gradients generated by ATP producing systems such as the mitochondria and the glycolytic pathway. However, subcellular microenvironments can develop with ATP deficiency due to increases in local ATP consumption. Alternatively, ATP production can be reduced during bioenergetic stress during hypoxia. Mammalian cells therefore need to have the capacity to alter their metabolism and energy distribution strategies to compensate for local ATP deficits while also controlling ATP production. It is highly likely that satisfying the bioenergetic requirements of the cell involves the regulated distribution of ATP producing systems to areas of high ATP demand within the cell. Recently, the distribution (both spatially and temporally) of ATP-producing systems has become an area of intense investigation. Here, we review what is known (and unknown) about intracellular energy production and distribution and explore potential mechanisms through which this targeted distribution can be altered in hypoxia, with the aim of stimulating investigation in this important, yet poorly understood field of research.

Cross-talk between insulin resistance and nitrogen species in hypoxia leads to deterioration of tissue and homeostasis

Hypoxia has been linked with insulin resistance as it produces changes in the metabolism of the cell; in which the adipocytes impede the insulin receptor tyrosine, phosphorylation, directing at decreased levels of transport of glucose. At this juncture, we are focusing on cross-talk between insulin resistance and nitrogen species in hypoxia, leading to the deterioration of tissue and homeostasis. Physiological levels of nitric oxide play a very crucial role in acting as a priority effector and signaling molecule, arbitrating the body's responses to hypoxia. Both ROS and RNS are associated with a reduction in IRS1 phosphorylation in tyrosine, which leads to reduced levels of IRS1 content and insulin response, which further leads to insulin resistance. Cellular hypoxia is a trigger to inflammatory mediators which signal tissue impairment and initiate survival requirements. But, hypoxia-mediated inflammation act as a protective role by an immune response and promotes wound healing during infection. In this review, we abridge the crosstalk between the inflammation and highlight the dysregulation in physiological consequences due to diabetes mellitus. Finally, we review various treatments available for its related physiological complications.

Comparative analysis of N-terminal cysteine dioxygenation and prolyl-hydroxylation as oxygen-sensing pathways in mammalian cells

In animals, adaptation to changes in cellular oxygen levels is coordinated largely by 2-oxoglutarate-dependent prolyl-hydroxylase domain (PHD) dioxygenase family members, which regulate the stability of their hypoxia-inducible factor (HIF) substrates to promote expression of genes that adapt cells to hypoxia. Recently, 2-aminoethanethiol dioxygenase (ADO) was identified as a novel O2-sensing enzyme in animals. Through N-terminal cysteine dioxygenation and the N-degron pathway, ADO regulates the stability of a set of non-transcription factor substrates; the regulators of G-protein signaling 4, 5. and 16 and interleukin-32. Here, we set out to compare and contrast the in cellulo characteristics of ADO and PHD enzymes in an attempt to better understand their co-evolution in animals. We find that ADO operates to regulate the stability of its substrates rapidly and with similar O2-sensitivity to the PHD/HIF pathway. ADO appeared less sensitive to iron chelating agents or transition metal exposure than the PHD enzymes, possibly due to tighter catalytic-site Fe2+ coordination. Unlike the PHD/HIF pathway, the ADO/N-degron pathway was not subject to feedback by hypoxic induction of ADO, and induction of ADO substrates was well sustained in response to prolonged hypoxia. The data also reveal strong interactions between proteolytic regulation of targets by ADO and transcriptional induction of those targets, that shape integrated cellular responses to hypoxia. Collectively, our comparative analysis provides further insight into ADO/N-degron-mediated oxygen sensing and its integration into established mechanisms of oxygen homeostasis.

The hypoxia-inducible factor 1 pathway plays a critical role in the development of breast muscle myopathies in broiler chickens: a comprehensive review

In light of the increased worldwide demand for poultry meat, genetic selection efforts have intensified to produce broiler strains that grow at a higher rate, have greater breast meat yield (BMY), and convert feed to meat more efficiently. The increased selection pressure for these traits, BMY in particular, has produced multiple breast meat quality defects collectively known as breast muscle myopathies (BMM). Hypoxia has been proposed as one of the major mechanisms triggering the onset and occurrence of these myopathies. In this review, the relevant literature on the causes and consequences of hypoxia in broiler breast muscles is reviewed and discussed, with a special focus on the hypoxia-inducible factor 1 (HIF-1) pathway. Muscle fiber hypertrophy induced by selective breeding for greater BMY reduces the space available in the perimysium and endomysium for blood vessels and capillaries. The hypoxic state that results from the lack of circulation in muscle tissue activates the HIF-1 pathway. This pathway alters energy metabolism by promoting anaerobic glycolysis, suppressing the tricarboxylic acid cycle and damaging mitochondrial function. These changes lead to oxidative stress that further exacerbate the progression of BMM. In addition, activating the HIF-1 pathway promotes fatty acid synthesis, lipogenesis, and lipid accumulation in myopathic muscle tissue, and interacts with profibrotic growth factors leading to increased deposition of matrix proteins in muscle tissue. By promoting lipidosis and fibrosis, the HIF-1 pathway contributes to the development of the distinctive phenotypes of BMM, including white striations in white striping-affected muscles and the increased hardness of wooden breast-affected muscles.

Modulation of Radiation Doses and Chimeric Antigen Receptor T Cells: A Promising New Weapon in Solid Tumors-A Narrative Review

Tumor behavior is determined by its interaction with the tumor microenvironment (TME). Chimeric antigen receptor (CART) cell therapy represents a new form of cellular immunotherapy (IT). Immune cells present a different sensitivity to radiation therapy (RT). RT can affect tumor cells both modifying the TME and inducing DNA damage, with different effects depending on the low and high doses delivered, and can favor the expression of CART cells. CART cells are patients' T cells genetically engineered to recognize surface structure and to eradicate cancer cells. High-dose radiation therapy (HDRT, >10-20 Gy/fractions) converts immunologically "cold" tumors into "hot" ones by inducing necrosis and massive inflammation and death. LDRT (low-dose radiation therapy, >5-10 Gy/fractions) increases the expansion of CART cells and leads to non-immunogenetic death. An innovative approach, defined as the LATTICE technique, combines a high dose in higher FDG- uptake areas and a low dose to the tumor periphery. The association of RT and immune checkpoint inhibitors increases tumor immunogenicity and immune response both in irradiated and non-irradiated sites. The aim of this narrative review is to clarify the knowledge, to date, on CART cell therapy and its possible association with radiation therapy in solid tumors.

USP10 Contributes to Colon Carcinogenesis via mTOR/S6K Mediated HIF-1α but Not HIF-2α Protein Synthesis

Colorectal cancer ranks among the third most common human malignant diseases and is one of the leading causes of cancer-related deaths globally. Colon cancer cells are hypoxic and display disturbed protein homeostasis. Ubiquitin-ligase-initiated proteasomal degradation as well as its prevention by deubiquitinases (DUBs) are supposed to contribute to the above-mentioned disturbances. However, not much is known about the involvement of ubiquitinating and deubiquitinating enzymes in colon cancer and their effect on the hypoxia response. Here, we identify the DUB ubiquitin-specific protease 10 (USP10) as an important player in the control of colon cancer progression and a new modifier of the hypoxia response. Mechanistically, we show that knockout of USP10 in different colon cancer cells causes an elevation in HIF-1α but not HIF-2α protein levels under both normoxic and hypoxic conditions. In addition, the lack of USP10 increased cellular migration, reduced cell adhesion, and switched the energy phenotype towards increased glycolysis and enhanced extracellular acidification. These changes were at least partially caused by HIF-1α, as the knockdown of HIF-1α rescued the cellular phenotype caused by USP10 deficiency. Interestingly, the USP10-dependent increase in HIF-1 α was neither caused by enhanced transcription nor prolonged half-life but via mTOR/S6K mediated HIF-1α protein synthesis. Together, the current findings indicate that USP10 is able to participate in colon carcinogenesis by modulating the hypoxia response and may therefore represent a new therapeutic target.

Cytokine induction of HIF-1α during normoxia in A549 human lung carcinoma cells is regulated by STAT1 and JNK signalling pathways

Hypoxia inducible factor-1ɑ (HIF-1ɑ) is the regulatory subunit of the HIF-1 transcription factor that is a regulator of cell physiological responses to hypoxia. However, the biological function and regulatory mechanisms controlling HIF-1α in normoxia are poorly understood. Here, we first examined the role of HIF-1α in the inflammatory activation of A549 human lung carcinoma cells in normoxia. Inactivation of the HIF-1α gene by CRISPR/Cas9 reduced the secretion of CXCL8 induced by stimulation with a cytokine mixture (CM) consisting of IL-1, TNFα and IFNγ. We next determined that cytokines act co-operatively to induce expression and nuclear accumulation of HIF-1α. To investigate the signalling mechanisms by which cytokines induce HIF-1α in normoxia, pharmacological inhibitors against the Jak/STAT, PI3K, NFκB, MEK/ERK, and JNK pathways were used. Inhibition of the Jak/STAT and JNK pathways inhibited the induction and nuclear accumulation of HIF-1ɑ by cytokines. Furthermore, siRNA knockdown of STAT1 and JNK also reduced the induction of HIF-1α by cytokines. Finally, pharmacological inhibition of these two pathways also blocked the trans-activation of HIF-1. These findings have implications for understanding the role and regulatory mechanisms of HIF-1ɑ in inflammation and cell biology.

Leptin-VEGF crosstalk in excess body mass and related disorders: A systematic review

By 2030, it is expected that a billion people will have suffer from obesity. Adipose tissue synthesizes leptin, an adipokine that affects cardiovascular risk. Leptin intensifies the synthesis of vascular endothelial growth factor (VEGF). Our study reviews recent reports on leptin-VEGF crosstalk in obesity and related disorders. PubMed, Web of Science, Scopus, and Google Scholar were searched. One hundred and one articles involving human, animal, and in vitro research were included. In vitro studies show the crucial role of interaction between endothelial cells and adipocytes and hypoxia as a factor that intensifies leptin's effects on VEGF. Leptin-VEGF crosstalk promotes the progression of cancer. The animal research reveal that a high-fat diet enhances leptin and VEGF crosstalk. Genetic and epigenetic mechanisms and procreator-offspring programming may be involved in leptin-VEGF crosstalk. Some female-specific characteristics of leptin-VEGF relation in obesity were observed. The human studies have shown that increased leptin and VEGF synthesis and leptin-VEGF crosstalk are factors linking obesity with elevated cardiovascular risk. The studies of the last 10 years documented a range of significant aspects of leptin-VEGF crosstalk specific for obesity and related disorders, shedding new light on the link between obesity and increased cardiovascular risk.

Stroke by inducing HDAC9-dependent deacetylation of HIF-1 and Sp1, promotes TfR1 transcription and GPX4 reduction, thus determining ferroptotic neuronal death

Background: The inhibition of histone deacetylase 9 (HDAC9) represents a promising druggable target for stroke intervention. Indeed, HDAC9 is overexpressed in neurons after brain ischemia where exerts a neurodetrimental role. However, mechanisms of HDAC9-dependent neuronal cell death are not yet well established. Methods: Brain ischemia was obtained in vitro by primary cortical neurons exposed to glucose deprivation plus reoxygenation (OGD/Rx) and in vivo by transient middle cerebral artery occlusion. Western blot and quantitative real-time polymerase chain reaction were used to evaluate transcript and protein levels. Chromatin immunoprecipitation was used to evaluate the binding of transcription factors to the promoter of target genes. Cell viability was measured by MTT and LDH assays. Ferroptosis was evaluated by iron overload and 4-hydroxynonenal (4-HNE) release. Results: Our results showed that HDAC9 binds to hypoxia-inducible factor 1 (HIF-1) and specificity protein 1 (Sp1), two transcription activators of transferrin 1 receptor (TfR1) and glutathione peroxidase 4 (GPX4) genes, respectively, in neuronal cells exposed to OGD/Rx. Consequently, HDAC9 induced: (1) an increase in protein level of HIF-1 by deacetylation and deubiquitination, thus promoting the transcription of the pro-ferroptotic TfR1 gene; and (2) a reduction in Sp1 protein levels by deacetylation and ubiquitination, thus resulting in a down-regulation of the anti-ferroptotic GPX4 gene. Supporting these results, the silencing of HDAC9 partially prevented either HIF-1 increase and Sp1 reduction after OGD/Rx. Interestingly, silencing of the neurodetrimental factors, HDAC9, HIF-1, or TfR1 or the overexpression of the prosurvival factors Sp1 or GPX4 significantly reduced a well-known marker of ferroptosis 4-HNE after OGD/Rx. More important, in vivo, intracerebroventricular injection of siHDAC9 reduced 4-HNE levels after stroke by preventing: (1) HIF-1 and TfR1 increase and thus the augmented intracellular iron overload; and (2) a reduction of Sp1 and its target gene GPX4. Conclusions: Collectively, results obtained suggest that HDAC9 mediates post-traslational modifications of HIF-1 and Sp1 that, in turn, increases TfR1 and decreases GPX4 expression, thus promoting neuronal ferroptosis in in vitro and in vivo models of stroke.

Identification of Signature Genes of Dilated Cardiomyopathy Using Integrated Bioinformatics Analysis

Dilated cardiomyopathy (DCM) is characterized by left ventricular or biventricular enlargement with systolic dysfunction. To date, the underlying molecular mechanisms of dilated cardiomyopathy pathogenesis have not been fully elucidated, although some insights have been presented. In this study, we combined public database resources and a doxorubicin-induced DCM mouse model to explore the significant genes of DCM in full depth. We first retrieved six DCM-related microarray datasets from the GEO database using several keywords. Then we used the "LIMMA" (linear model for microarray data) R package to filter each microarray for differentially expressed genes (DEGs). Robust rank aggregation (RRA), an extremely robust rank aggregation method based on sequential statistics, was then used to integrate the results of the six microarray datasets to filter out the reliable differential genes. To further improve the reliability of our results, we established a doxorubicin-induced DCM model in C57BL/6N mice, using the "DESeq2" software package to identify DEGs in the sequencing data. We cross-validated the results of RRA analysis with those of animal experiments by taking intersections and identified three key differential genes (including BEX1, RGCC and VSIG4) associated with DCM as well as many important biological processes (extracellular matrix organisation, extracellular structural organisation, sulphur compound binding, and extracellular matrix structural components) and a signalling pathway (HIF-1 signalling pathway). In addition, we confirmed the significant effect of these three genes in DCM using binary logistic regression analysis. These findings will help us to better understand the pathogenesis of DCM and may be key targets for future clinical management.

Intermittent hypoxia-induced enhancement of sociability and working memory associates with CNTNAP2 upregulation

Introduction

Hypoxia is an environmental risk factor for many disorders throughout life. Perinatal hypoxia contributes to autism spectrum disorder (ASD), while hypoxic conditions in the elderly facilitate memory deficits. However, the effects of hypoxia on adolescence remains elusive. CNTNAP2 is a critical molecule in ASD pathogenesis with undefined mechanisms. We investigate hypoxia’s impact on adolescence and the underlying mechanism related to CNTNAP2.

Methods

Three-chamber social approach test, Y maze, Morris Water Maze and Open Field Test were applied to evaluate behavioral alterations. Immunoblotting, 5′- RACE and dual-luciferase reporter assay were performed to examine CNTNAP2 protein expression, transcription start site (TSS) of human CNTNAP2 gene and CNTNAP2 promoter activity, respectively.

Results

Intermittent hypoxia treatment improved social behaviors and working memory in adolescent mice. CNTNAP2 was increased in the brains of hypoxia-treated mice. The sequencing results identified the TSS at 518 bp upstream of the translation start site ATG. Hypoxia upregulated CNTNAP2 by interacting with functional hypoxia response elements in CNTNAP2 promoter.

Conclusion

Intermittent hypoxia enhanced sociability and working memory associated with CNTNAP2 upregulation. Our study provides novel insights into intermittent hypoxia’s impact on development and the interaction between genetic and environmental risk factors in ASD pathogenesis.

A study of survival strategies for improving acclimatization of lowlanders at high-altitude

Human Acclimatization and therapeutic approaches are the core components for conquering the physiological variations at high altitude (≥2500 m) exposure. The declined atmospheric pressure and reduced partial pressure of oxygen at high altitudes tend to decrease the temperature by several folds. Hypobaric hypoxia is a major threat to humanity at high altitudes, and its potential effects include altitude mountain sickness. On severity, it may lead to the development of conditions like high-altitude cerebral edema (HACE) or high-altitude pulmonary edema (HAPE) and cause unexpected physiological changes in the healthy population of travelers, athletes, soldiers, and low landers while sojourning at high altitude. Previous investigations have been done on long-drawn-out acclimatization strategies such as the staging method to prevent the damage caused by high-altitude hypobaric Hypoxia. Inherent Limitations of this strategy hamper the daily lifestyle and time consuming for people. It is not suitable for the rapid mobilization of people at high altitudes. There is a need to recalibrate acclimatization strategies for improving health protection and adapting to the environmental variations at high altitudes. This narrative review details the geographical changes and physiological changes at high altitudes and presents a framework of acclimatization, pre-acclimatization, and pharmacological aspects of high-altitude survival to enhance the government efficacy and capacity for the strategic planning of acclimatization, use of therapeutics, and safe de-induction from high altitude for minimizing the life loss. It's simply too ambitious for the importance of the present review to reduce life loss, and it can be proved as the most essential aspect of the preparatory phase of high-altitude acclimatization in plateau regions without hampering the daily lifestyle. The application of pre-acclimatization techniques can be a boon for people serving at high altitudes, and it can be a short bridge for the rapid translocation of people at high altitudes by minimizing the acclimatization time.

Potential role of endoplasmic reticulum stress in broiler woody breast myopathy

Although broiler (meat-type) chickens are one of the most efficient protein sources that supports the livelihoods and food security of billions of people worldwide, they are facing several challenges. Due to its unknown etiology and heavy economic impact, woody breast (WB) myopathy is one of the most challenging problems facing the poultry industry, and for which there is no effective solution. Here, using a primary chicken myotube culture model, we show that hypoxia and endoplasmic reticulum (ER) stress are an integral component of the etiology of the myopathy. Multiple components of the ER stress response are significantly upregulated in WB as compared with normal muscle, and this response was mimicked by hypoxic conditions in chicken primary myotube culture. In addition, apoptotic pathways were activated as indicated by increases in active caspase 3 protein levels in both WB-affected tissues and hypoxic myotube culture, and caspase 3 activity and apoptosis in hypoxic myotube culture. Finally, as a phenotypic hallmark of WB is enhanced fibrosis and increased collagen aggregation, here, we show that hypoxic conditions increase collagen 1A1 and 1A2 gene expression, as well as collagen 1 protein levels in primary myotubes. These effects were partially reversed by tauroursodeoxycholic acid (TUDCA), an ER-stress inhibitor, in myotube culture. Taken together, these findings indicate that hypoxia and ER stress are present in WB, hypoxia can upregulate the cell death arm of the unfolded protein response (UPR) and lead to collagen production in a culture model of WB. This opens new vistas for potential mechanistic targets for future effective interventions to mitigate this myopathy.

Hypoxia-induced UBE2K promotes the malignant progression of HCC

BACKGROUND

Hypoxia critically drives malignant tumor development and is characteristic of hepatocellular carcinoma (HCC), where HIF-1α plays a crucial role. The ubiquitin-conjugating enzyme E2K (UBE2K) is known to participate in the advancement of several human cancers. However, the role of UBE2K in HCC or whether it is a hypoxia-responsive gene remains to be further identified.

METHOD

We performed a microarray to measure the gene expression differences between normoxia and hypoxia. CoCl2 mimicked the hypoxic condition. The protein and RNA expression of HIF-1α, UBE2K, and Actin in HCC cells were measured by western blotting(WB) and RT-qPCR, respectively. Immunohistochemical (IHC) staining analyzed the expression of UBE2K and HIF-1α in HCC tissues. CCK-8 and colony formation assay evaluated the HCC cell growth. Scratch healing and transwell assays were used to detect the migration capability of the cells. Lipofectamine 3000 was used to transfect the plasmids or siRNAs to HCC cells.

RESULTS

We identified UBE2K as a potential hypoxia-responsive gene. Our study showed that hypoxia induced HIF-1α-mediated increase of UBE2K levels in HCC cells, which decreased under HIF-1α deficiency under hypoxia. Further bioinformatics analysis based on UALCAN and GEPIA databases confirmed that UBE2K was highly expressed in HCC tissues and positively associated with HIF-1α expression. Functionally, Hep3B and Huh7 cell proliferation and migration were stimulated upon UBE2K overexpression, while the UBE2K knockdown suppressed such effect. Furthermore, functional rescue experiment proved that depletion of UBE2K inhibited hypoxia-induced cell proliferation and migration in HCC cells. In contrast, enhancing UBE2K levels rescued cell proliferation and migration repression caused by HIF-1α deficiency in hypoxia.

CONCLUSION

Our results established UBE2K as a potential hypoxia-inducible gene in HCC cells, positively regulated by HIF-1α in hypoxia. Moreover, UBE2K served as an oncogene and cooperated with HIF-1α to form a functional HIF-1α/UBE2K axis to trigger HCC progression, highlighting a potential application of UBE2K as a therapeutic target for HCC treatment.

RP11-367G18.1 V2 enhances clear cell renal cell carcinoma progression via induction of epithelial-mesenchymal transition

PURPOSE

Metastasis is the end stage of renal cell carcinoma (RCC), and clear cell renal cell carcinoma (ccRCC) is the most common malignant subtype. The hypoxic microenvironment is a common feature in ccRCC and plays an essential role in the regulation of epithelial-mesenchymal transition (EMT). Accumulating evidence manifests that long non-coding RNAs (lncRNAs) participate in RCC tumorigenesis and regulate hypoxia-induced EMT. Here, we identified a lncRNA RP11-367G18.1 induced by hypoxia, that was overexpressed in ccRCC tissues.

METHODS

A total of 216 specimens, including 149 ccRCC tumor samples and 67 related normal kidney parenchyma tissue samples, were collected. To investigate the biological fucntions of RP11.367G18.1 in ccRCC, migration, invasion, soft agar colony formation, xenograft tumorigenicity assays, and tail vein and orthotopic metastatic mouse models were performed. The relationship between RP11-367G18.1 and downstream signaling was analyzed utilizing reporter assay, RNA pull-down, chromatin immunopreciptation, and chromatin isolation by RNA purification assays.

RESULTS

Hypoxic conditions and overexpression of HIF-1α increased the level of RP11-367G18.1. RP11-367G18.1 induced EMT and enhanced cell migration and invasion through variant 2. Inhibition of RP11-367G18.1 variant 2 reversed hypoxia-induced EMT phenotypes. An in vivo study revealed that RP11-367G18.1 variant 2 was required for hypoxia-induced tumor growth and metastasis in ccRCC. Mechanistically, RP11-367G18.1 variant 2 interacted with p300 histone acetyltransferase to regulate lysine 16 acetylation on histone 4 (H4K16Ac), thus contributing to hypoxia-regulated gene expression. Clinically, RP11-367G18.1 variant 2 was upregulated in ccRCC tissues, particularly metastatic ccRCC tissues, and it is linked to poor overall survival.

CONCLUSION

These findings demonstrate the prognostic value and EMT-promoting role of RP11-367G18.1 and indicate that this lncRNA may provide a therapeutic target for ccRCC.