Hypoxia-inducible Factor-1alpha Expression Research Articles

HIF-1α participates in the regulation of S100A16-HRD1-GSK3β/CK1α pathway in renal hypoxia injury

S100 calcium-binding protein 16 (S100A16) is implicated in both chronic kidney disease (CKD) and acute kidney injury (AKI). Previous research has shown that S100A16 contributes to AKI by facilitating the ubiquitylation and degradation of glycogen synthase kinase 3β (GSK3β) and casein kinase 1α (CK1α) through the activation of HMG-CoA reductase degradation protein 1 (HRD1). However, the mechanisms governing S100A16-induced HRD1 activation and the upregulation of S100A16 expression in renal injury are not fully understood. In this study, we observed elevated expression of Hypoxia-inducible Factor 1-alpha (HIF-1α) in the kidneys of mice subjected to ischemia-reperfusion injury (IRI). S100A16 deletion attenuated the increased HIF-1α expression induced by IRI. Using a S100A16 knockout rat renal tubular epithelial cell line (NRK-52E cells), we found that S100A16 knockout effectively mitigated apoptosis during hypoxic reoxygenation (H/R) and cell injury induced by TGF-β1. Our results revealed that H/R injuries increased both protein and mRNA levels of HIF-1α and HRD1 in renal tubular cells. S100A16 knockout reversed the expressions of HIF-1α and HRD1 under H/R conditions. Conversely, S100A16 overexpression in NRK-52E cells elevated HIF-1α and HRD1 levels. HIF-1α overexpression increased HRD1 and β-catenin while decreasing GSK-3β. HIF-1α inhibition restored HRD1 and β-catenin upregulation and GSK-3β downregulation by cellular H/R injury. Notably, Chromatin immunoprecipitation (ChIP) and luciferase reporter assays demonstrated HIF-1α binding signals on the HRD1 promoter, and luciferase reporter gene assays confirmed HIF-1α‘s transcriptional regulation of HRD1. Additionally, we identified Transcription Factor AP-2 Beta (TFAP2B) as the upregulator of S100A16. ChIP and luciferase reporter assays confirmed TFAP2B as a transcription factor for S100A16. In summary, this study identifies TFAP2B as the transcription factor for S100A16 and demonstrates HIF-1α regulation of HRD1 transcription within the S100A16-HRD1-GSK3β/CK1α pathway during renal hypoxia injury. These findings provide crucial insights into the molecular mechanisms of kidney injury, offering potential avenues for therapeutic intervention.

Linagliptin ameliorates tacrolimus-induced renal injury: role of Nrf2/HO-1 and HIF-1α/CTGF/PAI-1

BackgroundTacrolimus (TAC) is a frequently used immunosuppressive medication in organ transplantation. However, its nephrotoxic impact limits its long-term usage. This study aims to investigate the effect of linagliptin (Lina) on TAC-induced renal injury and its underlying mechanisms.Methods and resultsThirty-two Sprague Dawley rats were treated with TAC (1.5 mg/kg/day, subcutaneously) and/or Lina (5 mg/kg/day, orally) for 4 weeks. Histological examination was conducted, and serum and urinary biomarkers were measured to assess kidney function and integrity. Furthermore, ELISA, Western blot analysis and immunohistochemical assay were employed to determine signaling molecules of oxidative stress, profibrogenic, hypoxic, and apoptotic proteins. Tacrolimus caused renal dysfunction and histological deterioration evidenced by increased serum creatinine, blood urea nitrogen (BUN), urinary cystatin C, and decreased serum albumin as well as elevated tubular injury and interstitial fibrosis scores. Additionally, TAC significantly increased the expression of collagen type-1, alpha-smooth muscle actin (α-SMA), plasminogen activator inhibitor-1 (PAI-1), and transforming growth factor-beta1 (TGF-β1) renal content. Moreover, TAC decreased the expression of nuclear factor erythroid-2-related factor2 (Nrf2), heme oxygenase 1 (HO-1), and mitochondrial superoxide dismutase (SOD2). In addition, TAC increased protein expression of hypoxia-inducible factor1-alpha (HIF-1α), connective tissue growth factor (CTGF), inducible nitric oxide synthase (iNOS), 8-hydroxy-2-deoxyguanosine (8-OHdG), as well as nitric oxide (NO), 4-hydroxynonenal, caspase-3 and Bax renal contents. Furthermore, TAC decreased Bcl-2 renal contents. The Lina administration markedly attenuated these alterations.ConclusionLina ameliorated TAC-induced kidney injury through modulation of oxidative stress, hypoxia, and apoptosis related proteins.

Sphingolipid biosynthesis is essential for metabolic rewiring during TH17 cell differentiation.

T helper 17 (TH17) cells are implicated in autoimmune diseases, and several metabolic processes are shown to be important for their development and function. In this study, we report an essential role for sphingolipids synthesized through the de novo pathway in TH17 cell development. Deficiency of SPTLC1, a major subunit of serine palmitoyl transferase enzyme complex that catalyzes the first and rate-limiting step of de novo sphingolipid synthesis, impaired glycolysis in differentiating TH17 cells by increasing intracellular reactive oxygen species (ROS) through enhancement of nicotinamide adenine dinucleotide phosphate oxidase 2 activity. Increased ROS leads to impaired activation of mammalian target of rapamycin C1 and reduced expression of hypoxia-inducible factor 1-alpha and c-Myc-induced glycolytic genes. SPTLCI deficiency protected mice from developing experimental autoimmune encephalomyelitis and experimental T cell transfer colitis. Our results thus show a critical role for de novo sphingolipid biosynthetic pathway in shaping adaptive immune responses with implications in autoimmune diseases.

Kreotoxin A administration inhibits hyperproliferation and inflammation of human ear keloid tissue and keloid-derived fibroblasts by downregulating HIF-1α expression

Keloids represent a prevalent dermal fibroproliferative disorder. They only affect humans and exhibit several tumor characteristics, such as excessive extracellular matrix (ECM) deposition, which usually occurs after skin injury. Kreotoxin type A (KTA) can inhibit the release of acetylcholine, and thereby inhibit the proliferation of keloid fibroblasts and reducing the formation of scars. Thus, KTA could be used as a therapeutic agent for keloids. However, the mechanisms of action of KTA in keloid treatment remain unclear. In this study, we aimed to explore the underlying mechanisms of action of KTA in human keloid treatment using human tissue and a cell-based model. Integrative microarray analysis revealed that hypoxia-inducible factor 1-alpha (HIF-1α) expression was frequently upregulated in hypertrophic scar and keloid tissues, whereas it was downregulated in the KTA-treated samples. Furthermore, KTA addition to keloid-derived fibroblasts (KDFs) reduced the growth rate and viability, induced apoptosis, and decreased inflammation and oxidative stress in KDFs. However, overexpression of HIF-1α restored cell number and survival, decreased apoptosis, and promoted inflammation and oxidative stress in KTA-treated KDFs. Furthermore, KTA treatment reduced the expression of ECM proteins, including vascular endothelial growth factor (VEGF), collagen I and III, whereas HIF-1α overexpression abolished the effects of KTA on KDFs. In conclusion, our findings provide novel insights into the mechanisms of action of KTA as a potential therapeutic agent for keloids via modulating HIF-1α expression.

Microneedle Patch for Transdermal Sequential Delivery of KGF-2 and aFGF to Enhance Burn Wound Therapy.

Severe burn wounds usually destroy key cells' functions of the skin resulting in delayed re-epithelization and wound regeneration. Promoting key cells' activities is crucial for burn wound repair. It is well known that keratinocyte growth factor-2 (KGF-2) participates in the proliferation and morphogenesis of epithelial cells while acidic fibroblast growth factor (aFGF)is a key mediator for fibroblast and endothelial cell growth and differentiation. However, thick eschar and the harsh environment of a burn wound often decrease the delivery efficiency of fibroblast growth factor (FGF) to the wound site. Therefore, herein a novel microneedle patch for sequential transdermal delivery of KGF-2 and aFGF is fabricated to enhance burn wound therapy. aFGF is first loaded in the nanoparticle (NPaFGF) and then encapsulated NPaFGF with KGF-2 in the microneedle patch (KGF-2/NPaFGF@MN). The result shows that KGF-2/NPaFGF@MN can successfully get across the eschar and sequentially release KGF-2 and aFGF. Additional data demonstrated that KGF-2/NPaFGF@MN achieved a quicker wound closure rate with reduced necrotic tissues, faster re-epithelialization, enhanced collagen deposition, and increased neo-vascularization. Further evidence suggests that improved wound healing is regulated by significantly elevated expressions of hypoxia-inducible factor-1 alpha(HIF-1ɑ) and heat shock protein 90 (Hsp90) in burn wounds. All these data proved that KGF-2/NPaFGF@MN is an effective treatment for wound healing of burns.

Abstract 1520: A novel cluster of cytolytic alpha/beta TCR+CD4−CD8−T cells originating from CD8+T cells with potent innate-like T cell killing ability: implicating adoptive T cell transfer therapy for hepatocellular carcinoma

Abstract Tumor immunotherapies represent promising strategies for treating various cancers, including hepatocellular carcinoma. In this context, immune cells, including the adoptive T cell transfer treatment, become the focus of interests. Notably, alpha/beta TCR+CD4−CD8−T (DNT) cells is a subgroup of T cells that is ignored for a long time but was re-focused recently. These DNT cells are a group of cells with opposite functions in different condition, including pro-inflammatory or suppressive functions and possibly originated from over-stimulation of peripheral CD4+T cells/CD8+T cells or a special group of T cells formed in thymus. In our research results, we have found these DNT cells increased in murine hepatoma model, especially in the tumor microenvironment. In addition, these DNT cells from tumor microenvironment of murine hepatoma possessed potent tumor-killing ability. Furthermore, we analyzed the transcriptome profile of T cells in tumor microenvironment by single cell RNAseq approach (CITE-seq). We found DNT cells could be categorized into two main clusters, one is cytolytic DNT cells, resemble the potent CD8+T cells, and another is the CD4+T cell-like DNT cells. These cytolytic DNT cells are not exhausted but with high expression of cytolytic molecule and low hypoxia-inducible factor-1alpha (HIF-1a) expression. By trajectory analysis, cytolytic DNT cells come from the conventional CD8+T cells but following a unique developmental pathway that is different from the exhausted CD8+T cells. Interesting, these cytolytic DNT cells also expressed high level of Fcer1g molecule, a marker of innate CD8+T cells. In addition, these DNT cells could be generated and expanded in-vitro by IL-15 without TCR activation. In conclusion, we identified a cluster of cytolytic DNT cells, originated from CD8+T cells, exhibits innate T cells behavior and potent killing ability. In addition, these cytolytic DNT cells could be generated and expanded in-vitro for the adoptive T cell transfer treatment of hepatoma. Citation Format: Cheng-Heng Wu, Te-Wei Tseng, Chen-Yang Huang, Ping-Hsun Ou, Yi-Chen Lin, Pin-Jung Chen, Po-Ting Lin, Chan-Keng Yang, Wei Teng, Tsung-Han Wu, Yung-Chang Lin, Chun-Yen Lin. A novel cluster of cytolytic alpha/beta TCR+CD4−CD8−T cells originating from CD8+T cells with potent innate-like T cell killing ability: implicating adoptive T cell transfer therapy for hepatocellular carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1520.

Dimethyloxalylglycine Suppresses SREBP1c and Lipogenic Gene Expressions in Hepatocytes Independently of HIF1A.

Dimethyloxalylglycine (DMOG) is a representative inhibitor of the prolyl hydroxylase domain (PHD), which mediates the degradation of hypoxia-inducible factor-1-alpha (HIF1A). DMOG exerts its pharmacological effects via the canonical pathway that involves PHD inhibition; however, it remains unclear whether DMOG affects lipogenic gene expression in hepatocytes. We aimed to elucidate the effects of DMOG on sterol regulatory element-binding protein-1c (SREBP1c), a master regulator of fatty acid synthesis in hepatocytes. DMOG treatment inhibited SREBP1c mRNA and protein expression in HepG2 and AML12 hepatocytes and reduced the transcript levels of SREBP1c-regulated lipogenic genes. A luciferase reporter assay revealed that DMOG inhibited the transcriptional activity of SREBP1c. Moreover, DMOG suppressed SREBP1c expression in mice liver. Mechanistically, treatment with DMOG enhanced the expression of HIF1A and insulin-induced gene 2 (INSIG2), which inhibits the activation of SREBP1c. However, HIF1A or INSIG2 knockdown failed to reverse the inhibitory effect of DMOG on SREBP1c expression, suggesting a redundant role of HIF1A and INSIG2 in terms of repressing SREBP1c. DMOG did not function through the canonical pathway involving inhibition of SREBP1c by PHD, highlighting the presence of non-canonical pathways that mediate its anti-lipogenic effect.

Effect of hypoxia-inducible factor-1 alpha expression on survival in patients with metastatic cervical squamous cell carcinoma treated with first-line chemotherapy and bevacizumab.

This study addresses the gap in understanding the prognostic relevance of hypoxia-inducible factor-1 alpha (HIF-1 alpha) expression in metastatic cervical squamous cell carcinoma (SCC) patients undergoing anti-vascular endothelial growth factor-based therapy. A retrospective multicenter study (n = 34) explored HIF-1 alpha expression via immunohistochemistry in patients treated with platinum chemotherapy and bevacizumab. Median progression-free survival (PFS) was significantly lower in the HIF-1 alpha low score group compared to the high score group (4.9 vs 12.9 months, P = 0.014). Similarly, the median overall survival (OS) was significantly reduced in the HIF-1 alpha low score group (8.3 vs 20.4 months, P = 0.006). This study, the first of its kind, highlights the prognostic significance of HIF-1 alpha expression in metastatic cervical SCC patients treated with bevacizumab-based therapy.

Natural Product-Based Glycolysis Inhibitors as a Therapeutic Strategy for Epidermal Growth Factor Receptor-Tyrosine Kinase Inhibitor-Resistant Non-Small Cell Lung Cancer.

Non-small cell lung cancer (NSCLC) is a leading cause of cancer-related deaths worldwide. Targeted therapy against the epidermal growth factor receptor (EGFR) is a promising treatment approach for NSCLC. However, resistance to EGFR tyrosine kinase inhibitors (TKIs) remains a major challenge in its clinical management. EGFR mutation elevates the expression of hypoxia-inducible factor-1 alpha to upregulate the production of glycolytic enzymes, increasing glycolysis and tumor resistance. The inhibition of glycolysis can be a potential strategy for overcoming EGFR-TKI resistance and enhancing the effectiveness of EGFR-TKIs. In this review, we specifically explored the effectiveness of pyruvate dehydrogenase kinase inhibitors and lactate dehydrogenase A inhibitors in combating EGFR-TKI resistance. The aim was to summarize the effects of these natural products in preclinical NSCLC models to provide a comprehensive understanding of the potential therapeutic effects. The study findings suggest that natural products can be promising inhibitors of glycolytic enzymes for the treatment of EGFR-TKI-resistant NSCLC. Further investigations through preclinical and clinical studies are required to validate the efficacy of natural product-based glycolytic inhibitors as innovative therapeutic modalities for NSCLC.

Decreased Angiopoietin Expression in Underactive Bladder Induced by Long-term Bladder Outlet Obstruction.

Ischemia of the bladder can occur if neovascular formation cannot keep pace with hypoxia induced by chronic bladder outlet obstruction (BOO). The aim of this study was to examine changes in angiogenesis growth factor expression generated by chronic BOO in a rat model of underactive bladder. Twenty female Sprague-Dawley rats aged 6 weeks were assigned to 4 groups (5 rats per group). Group 1 was the control. Group 2 underwent sham surgery. The rats in groups 3 and 4 underwent BOO and were followed up for 1 week and 8 weeks. Cystometry was carried out together with bladder tissue analysis at 1 week and 8 weeks postoperatively. Real-time polymerase chain reaction (PCR) assays were conducted to determine the expression level of angiogenesis-related growth factors. A hypoxia signaling pathway PCR array was additionally carried out. The group that underwent BOO for 8 weeks showed abnormal bladder function, with a diminished intercontraction interval, decreased maximal voiding pressure, and higher volume of residual urine (P<0.05). Hypoxia-inducible factor-1 alpha expression was elevated in this group. The expression levels of vascular endothelial growth factor (VEGF) and VEGF receptor messenger RNA (mRNA) in the BOO group were comparable to those in the control group. However, angiotensin/tie receptor mRNA expression levels increased at 1 week after BOO, but decreased at 8 weeks after BOO. In animals that underwent BOO, fewer blood vessels exhibited positive immunofluorescent staining for von Willebrand factor. Alterations were also seen in the hypoxia signaling pathway PCR array. In a rat model of underactive bladder caused by surgical BOO, reduced angiopoietin expression was demonstrated. This observation might underlie visceral ischemia and fibrosis associated with the procedure. The findings of this study might offer an improved understanding of the disease processes underlying BOO and facilitate selection of the appropriate time to repair the organ in this condition.

Glucose Regulates Glucose Transport and Metabolism via mTOR Signaling Pathway in Bovine Placental Trophoblast Cells.

It has been confirmed that improving the energy level of the diet contributed to the greater reproductive performance and birth weight of calves in periparturient dairy cows. To investigate the effect of glucose on nutrient transport during fetal development, the bovine placental trophoblast cells (BPTCs) were cultured in media with different glucose concentrations (1, 2, 4, 8, or 16 mg/mL). Subsequently, the BPTCs were cultured in media with 1, 8 mg/mL glucose and 8 mg/mL glucose plus 100 nmol/L rapamycin (the inhibitor of mTOR pathway). Compared with the 1 mg/mL glucose, the addition of 8 mg/mL glucose stimulated cell proliferation, upregulated the mRNA abundance of the glucose transporter GLUT1 and GLUT4, and increased the activity of glucose metabolism-related enzyme glucose-6-phosphate dehydrogenease (G6PD), lactate dehydrogenase (LDHA) and phosphoglycerate kinase 1 (PGK1), as well as adenosine-triphosphate (ATP) content (p < 0.05).Furthermore, compared with the treatment of 1 mg/mL glucose, adding 8 mg/mL of glucose-upregulated gene expression in the mTOR signaling pathway, including phosphatidylinositol3-kinase (PI3K), protein kinase B (Akt), mammalian target of rapamycin (mTOR) and 70 kDa ribosomal protein S6 kinase 2 (P70S6K) (p < 0.05).The supplementation of rapamycin downregulated the gene and protein expression of the mTOR signaling pathway, including mTOR, P70S6K, EIF4E-binding protein 1 (4EBP1), hypoxia-inducible factor 1-alpha (HIF-1α) and gene expression of glucose transporter upregulated by 8 mg/mL glucose (p < 0.05). Thus, these results indicated that the addition of 8 mg/mL glucose regulated the glucose transport and metabolism in BPTCs through the mTOR signaling pathway, thereby promoting the supply of nutrients to fetus.

Novel Risk Models and Promising Biomarkers for Prognostic Prediction in T-Cell Lymphoma with Pleural Effusion

Introduction: T-cell lymphomas (TCLs), a cluster of lymphoproliferative diseases, display high heterogeneity of characteristics, and lack for accurate prognostic models and precision treatment at present. Pleural effusion (PE) is a relatively severe manifestation of lymphomas, which has been found to be associated with worse prognosis in tumor patients, posing more challenges for risk stratification in TCL patients. Methods: Entire of 472 new diagnosed TCL patients were included from Shandong Provincial Hospital (2010-2022), and 130 among them with PE were retrospectively investigated to evaluate the prognostic value of clinical factors. The study was performed with the approval of the Medical Ethical Committee of Shandong Provincial Hospital, and all samples were collected with informed consents. RNA sequencing datasets GSE5584, GSE58445 and GSE6338 from GEO database were applied for the identification and function analysis of PE-related genes (PERGs). LASSO Cox regression analysis was utilized to reveal the prognostic role of PERGs in TCL patients. Immunohistochemistry (IHC) was applied to explore the expression and prognostic significance of HIF1A in TCLs. Results: 130 TCL patients with PE were found to display worse prognosis compared to non-PE group (P &amp;lt; 0.0001). Three clinical variables were confirmed as independently prognostic factors in TCL patients with PE, including serum albumin concentration (ALB) &amp;lt; 40 g/L (HR = 0.346, P = 0.0452), PE volume (PEV) &amp;gt; 500ml (HR = 2.192, P = 0.0269) and serum procalcitonin concentration (PCT) &amp;gt; 0.05ng/ml (HR = 3.408, P = 0.0036). After addition of these three variables to NCCN IPI, we constructed NAPP prognostic model (NAPP score = 3 × NCCN IPI - ALB + 8 × PEV + 12 × PCT) in TCL patients with PE. With an Akaike information criterion (AIC) of 363.14 and concordance index (C-index) of 0.71, NAPP prognostic model obviously improved the prediction performance of NCCN IPI (AIC = 741.01 and C-index = 0.52). Then we used the “cutoff” package in R to choose optimum marginal value, patients with NAPP risk score &amp;lt; 41 were deemed as low risk while ≥ 41 were high risk. Kaplan-Meier survival curve clarified that there was significant discrepancy of OS between the two groups (Fig. 1A, P &amp;lt; 0.0001). The 1-, 3-, and 5-year AUC values of NAPP for OS were 0.70, 0.64 and 0.64. The point estimated value of AUC at each prediction time was above 0.60 (Fig. 1A), suggesting that NAPP score had obvious superiority in predictive ability than current NCCN IPI and prognostic index for PTCL-unspecified (PIT) risk models. Subsequently, based on GSE55846, we found 50 miRNAs were differentially expressed (|log 2FC| &amp;gt; 1.5 and P &amp;lt; 0.05) between TCL patients with and without PE. Then, 239 predicted target genes of the 50 differentially expressed miRNAs were selected as PERGs based on miRTarBase and TargetScanHuman 8.0 databases. GO and KEGG analysis revealed the tight relationship between PERGs and tumor immunity. Besides, we constructed a signature including 4 PERGs (HIF1A, FERMT2, NFACT1 and COL1A1) in GSE58445. The 1-year AUC value for OS in the cohort was 0.78, indicating that PERGs signature had reliable predictive ability for OS in TCL patients. Moreover, the expression of hypoxia inducible factor-1 alpha (HIF1A) was verified to be decreased in TCL patients with PE through IHC. TCL patients with low expression of HIF1A suffered obviously inferior prognosis (Fig. 1B, P &amp;lt; 0.0001), especially in PE group. In non-PE group, there were no statistical differences of OS between the two groups based on HIF1A expression (P = 0.48). These results indicated that HIF1A might serve as a promising prognostic biomarker in TCL patients with PE. Conclusions: A novel NAPP risk model was firstly constructed and demonstrated to achieve accurate risk stratification for TCL patients with PE. PERGs, especially HIF1A, were closely related to tumor immune, and could act as molecular predictors for prognosis in TCL patients. These findings have the promising potential to facilitate the identification of high-risk population and the establishment of individualized treatment in TCL patients with PE.

Intravitreal Injection of ZYAN1 Restored Autophagy and Alleviated Oxidative Stress in Degenerating Retina via the HIF-1α/BNIP3 Pathway.

Mitochondrial autophagy plays a contributary role in the pathogenesis of retina degeneration (RD). ZYAN1 is a novel proline hydroxylase domain (PHD) inhibitor that can enhance the expression of hypoxia-inducible factor 1-alpha (HIF-1α). This study investigated whether ZYAN1 could alleviate progressive photoreceptor loss and oxidative damage in a pharmacologically induced RD model via the modulation of mitophagy. ZYAN1 was injected into the vitreous body of the RD model, and the retinal autophagy level was analyzed. The therapeutic effects of ZYAN1 were evaluated via a function examination, a morphological assay, in situ reactive oxygen species (ROS) detection, and an immunofluorescence assay. It was shown that the thickness of the outer nuclear layer (ONL) increased significantly, and visual function was efficiently preserved via ZYAN1 treatment. The mitochondria structure of photoreceptors was more complete in the ZYAN1-treated mice, and the number of autophagosomes also increased significantly. Membrane disc shedding and ROS overproduction were alleviated after ZYAN1 treatment, and the axonal cilia were more structurally intact. A Western blot analysis showed that the expression levels of the autophagy-related proteins LC3-B, Beclin-1, and ATG5 increased significantly after ZYAN1 treatment, while the expression of P62 was down-regulated. Moreover, the expression levels of HIF-1α and BNIP3 were up-regulated after ZYAN1 treatment. Therefore, an intravitreal injection of ZYAN1 can act as part of the pharmacologic strategy to modulate mitophagy and alleviate oxidative stress in RD. These findings enrich our knowledge of RD pathology and provide insights for the discovery of a therapeutic molecule.

Cytotoxic effects of Phenformin on ovarian cancer cells: expression of HIF-1α and PDK1 in the hypoxic microenvironment.

Today, many anticancer drugs are used clinically for ovarian cancer, one of the leading causes of cancer-related deaths in women. Phenformin is an antidiabetic drug of the biguanide class. It improves the antiproliferative activity in cancer cells. Hypoxia is an important component associated with ovarian cancer and its tumor microenvironment. The aim of this study was to investigate the anticancer effects of Phenformin in SKOV-3 human ovarian cancer cells under hypoxic conditions. SKOV-3 human ovarian cancer cells treated with different doses of Phenformin (0.5 mM, 1 mM, 2 mM, 5 mM) for 24 hours were subjected to WST-1 cell viability assay and Annexin V apoptosis assay. A dose-dependent decrease in cell viability with Phenformin treatment was observed. In addition, Phenformin activated percentage of apoptotic SKOV-3 cancer cells in a dose-dependent manner. In this study, Cobalt(II) chloride (CoCl2) treatment leads to increased hypoxia-inducible factor-1alpha (HIF-1α) expression and Phenformin can recover hypoxic condition. HIF-1α protein expression was significantly correlated with cell viability assay and apoptosis assay. We also found that Phenformin inhibits expression of phosphoinositide-dependent kinase 1 (PDK1) in SKOV-3 ovarian cancer cells. The ability to migrate to cancer cells was significantly reduced in a dose-dependent manner with Phenformin. This data demonstrates that Phenformin treatment can induce apoptosis and inhibit proliferation in ovarian cancer cells under hypoxic conditions. The findings reveal that HIF-1α is a new target for the treatment of ovarian cancer.

Hypoxic regulation of hypoxia inducible factor 1 alpha via antisense transcription

Impaired oxygen homeostasis is a frequently encountered pathophysiological factor in multiple complex diseases, including cardiovascular disease and cancer. While the canonical hypoxia response pathway is well characterized, less is known about the role of noncoding RNAs in this process. Here, we investigated the nascent and steady-state noncoding transcriptional responses in endothelial cells and their potential roles in regulating the hypoxic response. Notably, we identify a novel antisense long noncoding RNA that convergently overlaps the majority of the hypoxia inducible factor 1 alpha (HIF1A) locus, which is expressed across several cell types and elevated in atherosclerotic lesions. The antisense (HIF1A-AS) is produced as a stable, unspliced, and polyadenylated nuclear retained transcript. HIF1A-AS is highly induced in hypoxia by both HIF1A and HIF2A and exhibits anticorrelation with the coding HIF1A transcript and protein expression. We further characterized this functional relationship by CRISPR-mediated bimodal perturbation of the HIF1A-AS promoter. We provide evidence that HIF1A-AS represses the expression of HIF1a in cis by repressing transcriptional elongation and deposition of H3K4me3, and that this mechanism is dependent on the act of antisense transcription itself. Overall, our results indicate a critical regulatory role of antisense mediated transcription in regulation of HIF1A expression and cellular response to hypoxia.

Molecular mechanism of oroxyli semen against triple-negative breast cancer verified by bioinformatics and in vitro experiments.

This study aimed to use network pharmacology to predict the therapeutic mechanism of oroxyli semen (OS) on triple-negative breast cancer (TNBC) and validate it through in vitro experiments. The active ingredients and target proteins of OS were retrieved from the Traditional Chinese Medicine Systems Pharmacology database, and the TNBC-related target genes were obtained from the GeneCards database. The overlapping genes were used to construct a protein-protein interaction (PPI) network via the String database. Furthermore, we employed an online bioinformatics analysis platform (https://www.bioinformatics.com.cn/) to perform gene ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses to evaluate biological processes, molecular functions, and cellular components and generate simulated signal pathways. Additionally, molecular docking was used to evaluate the binding ability of small molecule drugs and signaling pathway targets. CCK8 assay was conducted to detect the effect of small molecule drugs on TNBC cell viability, and Western Blot was utilized to verify the expression of AKT, VEGF, and hypoxia-inducible factor 1-alpha (HIF-1α) proteins. Fifteen active ingredients and 166 therapeutic targets of OS were obtained from the Traditional Chinese Medicine Systems Pharmacology database. The Venn diagram revealed that 163 targets were related to TNBC. The protein-protein interaction network analysis identified AKT1, IL-6, JUN, vascular endothelial growth factor A (VEGFA), CASP3, and HIF-1α as potential core targets through which OS may treat TNBC. Furthermore, the molecular docking results indicated that the active ingredient chryseriol in OS had good binding ability with VEGFA, and HIF-1α. CCK8 assay results indicated that chryseriol inhibited the viability of MDA-MB-231 and BT-20 cells. Western Blot demonstrated that chryseriol intervention led to a decrease in VEGFA, and HIF-1α protein expression compared with the control group (P < .05), increased the cleaved PARP. OS may exert its therapeutic effects on TNBC through multiple cellular signaling pathways. Chryseriol, the active component of OS, can enhance the apoptosis of TNBC cells by targeting VEGFA/HIF-1α pathway. This study provided new insights into the potential therapeutic mechanism of OS for TNBC and may aid in the development of novel therapeutic approaches for TNBC.

Mild Hypoxia Postconditioning Induces Hypoxia-Inducible Factor 1 Alpha Expression and Improves the Neurobehavioral Abilities of Rats with Hypoxic-Ischemic Brain Damage

Background: While severe hypoxia is known to contribute to neurotoxicity and lead to abnormal behavior, mild hypoxia may have beneficial effects mediated through endogenous adaptive responses. Objectives: The present study aimed to investigate the effects of mild hypoxia postconditioning and long-term neurobehavioral ability rehabilitation after hypoxic-ischemic brain damage (HIBD). Methods: Seven-day-old rats underwent left carotid ligation followed by 2 hours of hypoxia stress. Rats received different protocols of mild hypoxia postconditioning for 5 days and underwent neurobehavioral testing during the last week of the study. Hypoxia-inducible factor 1 alpha (HIF-1a) expression was assessed, and neurobehavioral ability assays were performed. Results: Compared with the HIBD group, rats postconditioning with mild hypoxia showed increased HIF-1a expression, and their brain functions were better in neurobehavioral analyses. The rehabilitation of brain functions may be associated with high HIF-1a expression and better behavioral performance. Conclusions: Our findings indicate that mild hypoxia postconditioning improves neurobehavioral ability, and HIF-1a may be a potential mediator of the observed effects. Our findings suggest that there may be clinical implications for treating infants with HIBD.

TRIM14 Overexpression Induces Chemoresistance and Malignant Behaviors of Hepatocellular Carcinoma Cells by Activating the STAT3/HIF-1α Pathway.

Members of the tripartite motif (TRIM)-containing protein family have been found to be involved in the progression of hepatocellular carcinoma (HCC). TRIM14 exerts a promotive impact on several cancers. This study aimed to explore the function and mechanism of TRIM14 in HCC. TRIM14 expression in HCC tissues and HCC cell lines was detected. The overexpression or knockdown model of TRIM14 was established in HCC cell lines. Cell Counting Kit-8 (CCK-8) assay, flow cytometry, Transwell assay, RT-PCR, Western blot, and immunofluorescence were performed to verify the influence of TRIM14 on cell proliferation, sensitivity to chemotherapy drugs, apoptosis, migration, invasion, and autophagy. A xenograft tumor model was used to confirm the impact of TRIM14 on tumor cell growth. As shown by the data, TRIM14 level was notably higher in the tumor tissues of HCC patients than in the adjacent tissues. The overall survival rate of patients with a high TRIM14 expression was relatively lower than that of patients with a low TRIM14 expression. TRIM14 upregulation enhanced the proliferation, autophagy, migration, and invasion of HCC cells and chemoresistant HCC cells and decreased apoptosis. TRIM14 knockdown contributed to the opposite effects. In in vivo experiments, TRIM14 upregulation bolstered tumor growth. Western blot analysis revealed that TRIM14 upregulation boosted signal transducer and activator of transcription3 (STAT3) and hypoxia-inducible factor-1alpha (HIF-1α) expression, and TRIM14 knockdown suppressed their expression. Moreover, repressing STAT3 and HIF-1α could mitigate the tumor-promoting role of TRIM14 in HCC cells. Overall, TRIM14 facilitated malignant HCC development and induced chemoresistance in HCC cells by activating the STAT3/HIF-1α axis.

Transcription Factor EGR1 Facilitates Neovascularization in Mice with Retinopathy of Prematurity by Regulating the miR-182-5p/EFNA5 Axis.

Neovascularization is the hallmark of retinopathy of prematurity (ROP). Early growth response 1 (EGR1) has been reported as an angiogenic factor. This study was conducted to probe the regulatory mechanism of EGR1 in neovascularization in ROP model mice. The ROP mouse model was established, followed by determination of EGR1 expression and assessment of neovascularization [vascular endothelial growth factor-A (VEGF-A) and pigment epithelium-derived factor (PEDF)]. Retinal vascular endothelial cells were cultured and treated with hypoxia, followed by the tube formation assay. The state of oxygen induction was assessed by real-time quantitative polymerase chain reaction (RT-qPCR) and Western blot assay to determine hypoxia-inducible factor 1-alpha (HIF-1A). The levels of microRNA (miRNA)-182-5p and ephrin-A5 (EFNA5) in tissues and cells were determined by RT-qPCR. Chromatin immunoprecipitation and dual-luciferase assay were used to validate gene interaction. EGR1 and EFNA5 were upregulated in the retina of ROP mice while miR-182-5p was downregulated. EGR1 knockdown decreased VEGF-A and HIF-1A expression and increased PEDF expression in the retina of ROP mice. In vitro, EGR1 knockdown also reduced neovascularization. EGR1 binding to the miR-182-5p promoter inhibited miR-182-5p transcription and further promoted EFNA5 transcription. miR-182-5p downregulation or EFNA5 overexpression averted the inhibition of neovascularization caused by EGR1 downregulation. Overall, EGR1 bound to the miR-182-5p promoter to inhibit miR-182-5p transcription and further promoted EFNA5 transcription, thus promoting retinal neovascularization in ROP mice.

Activation of aryl hydrocarbon receptor by azatyrosine-phenylbutyric hydroxamide inhibits progression of diabetic retinopathy mice

Diabetic retinopathy (DR) is a severe consequence of long-term diabetes mellitus and may lead to vision loss. Retinal pigment epithelial (RPE) cells are a diverse group of retinal cells with varied metabolic and functional roles. In hypoxic conditions, RPE cells have been shown to produce angiogenic factors, such as vascular endothelial growth factor (VEGF), which is regulated by hypoxia-inducible factor 1-alpha (HIF1A). VEGF plays a crucial role in angiogenesis in DR. In the present study, we investigated whether azatyrosine-phenylbutyric hydroxamide (AZP) has therapeutic effect on DR therapy. In this study, we treated high glucose-activated human retinal pigment epithelial cells (ARPE-19) with and without AZP. The effector proteins were evaluated using western blotting. In the in vivo study, AZP was administered to the db/db mice as a DR animal model. Moreover, invasive imaging techniques such as optical coherence tomography (OCT), fundus photography, and fundus fluorescein angiography (FFA) were performed on the mice to assess DR progression. We found that treatment of AZP for 12 weeks reversed increasing DR retinal alterations in db/db mice, decreasing vascular density, retinal blood perfusion, retinal thickness, decreasing DR lesion, lipofuscin accumulation, HIF1A, VEGF, and inflammation factor expression. In addition, AZP treatment could activate the aryl hydrocarbon receptor AHR and reverse the high-glucose-induced HIF1A and VEGF in ARPE-19 cells and db/db mice. In conclusion, AZP activated AHR while inhibiting HIF1A and VEGF. This study indicates that AZP may be a promising therapeutic agent for treating DR.