Search Results (289)

Obstructive sleep apnea (OSA) is a prevalent disorder linked to metabolic complications such as diabetes and cardiovascular disease. By fragmenting normal sleep architecture, OSA perturbs the growth hormone/insulin-like growth factor (GH/IGF) axis and alters circulating levels of IGF-binding proteins (IGFBPs). A prior clinical observation of elevated IGFBP4 in OSA patients motivated the present investigation in a controlled animal model. Building on the previously reported protocol, OSA was induced in male C57BL/6 mice (9–12 weeks old) through intralingual injection of polytetrafluoroethylene (PTFE), producing tongue hypertrophy, intermittent airway obstruction, and hypoxemia. After 8–10 weeks, the study assessed (1) hypoxia biomarkers—including HIF-1α and VEGF expression—and (2) neurobehavioral outcomes in anxiety and cognition using the open-field and novel object recognition tests. PTFE-treated mice exhibited a significant increase in circulating IGFBP4 versus both baseline and control groups. Hepatic Igfbp4 mRNA was also upregulated. Behaviorally, PTFE mice displayed heightened anxiety-like behavior and impaired novel object recognition, paralleling cognitive deficits reported in human OSA. These findings validate the PTFE-induced model as a tool for studying OSA-related hypoxia and neurocognitive dysfunction, and they underscore IGFBP4 as a promising biomarker and potential mediator of OSA’s systemic effects. Full article

Background/Objectives: HIF-1α and ERRα are both implicated in breast cancer progression, yet their functional interplay remains poorly understood. This study investigates their molecular crosstalk in the context of hypoxia-induced drug resistance. Methods: MCF-7 (estrogen receptor, ER-positive) spheroids and CoCl₂-treated SK-BR-3 (ER-negative) cells were used to model tumor hypoxia. Protein expression, coimmunoprecipitation, chromatin immunoprecipitation (ChIP), pharmacological inhibition, and siRNA-mediated gene silencing were employed to assess physical and functional interactions. Immunohistochemistry (IHC) on a tissue microarray (TMA) of 168 invasive breast carcinomas was performed to evaluate clinical relevance. Results: ERRα levels remained unchanged under hypoxia, while its coactivator, Peroxisome Proliferator-Activated Receptor Gamma Coactivator-1 α (PGC-1α), was upregulated. ERRα physically interacted with HIF-1α and was required for HIF-1 transcriptional activity under hypoxic conditions. ChIP assays showed that ERRα-driven overexpression of Permeability glycoprotein 1 (P-gp) and Vascular Endothelial Growth Factor (VEGF) was mediated by HIF-1α binding to the MDR1 and VEGF promoters. Inhibition or silencing of ERRα reversed P-gp overexpression and restored intracellular doxorubicin. TMA analysis confirmed the clinical correlation between ERRα, HIF-1α, and P-gp expression, highlighting the role of ERRα in hypoxia-induced drug resistance. ERRα expression was independent of ER status, suggesting an estrogen-independent function. Conclusions: This study identifies a novel physical and functional interaction between ERRα and HIF-1α that promotes chemoresistance in hypoxic breast tumors. Targeting ERRα may represent a promising therapeutic strategy to overcome drug resistance in aggressive, ER-independent breast cancer subtypes. Full article

Background/Objectives: Colorectal cancer (CRC) patients undergoing chemotherapy often experience anemia, oxidative stress, and immune suppression, significantly impacting their quality of life and treatment outcomes. Normobaric oxygen (NBO) therapy, which delivers oxygen at atmospheric pressure with an elevated oxygen concentration, has shown the potential to enhance erythropoiesis, reduce oxidative stress, and modulate immune function. However, its efficacy in CRC patients remains underexplored. This study aims to evaluate the effects of NBO exposures on (1) supporting erythropoiesis by measuring erythropoietin (EPO) levels and hypoxia-inducible factor 1-alpha (HIF-1α), (2) reducing oxidative stress and improving stress and emotional well-being, and (3) modulating immune function by assessing cytokine profiles. Secondary objectives include assessing the impact of NBO on patient-reported outcome measures (PROMs) such as stress, anxiety, depression, and quality of life. Methods: This is a prospective, randomized, double-blind, placebo-controlled clinical trial. A total of 254 CRC patients undergoing chemotherapy will be randomized 1:1 to receive either active NBO therapy (n = 127, study group) or placebo NBO therapy (n = 127, control group). The intervention will consist of 10 NBO sessions over five weeks. Primary outcomes include biomarkers of erythropoiesis, oxidative stress, and immune response. Secondary outcomes assess quality of life and psychological well-being. Data will be collected at baseline, mid-intervention, post-intervention, and during two follow-up visits (3 and 6 months post-intervention). Results: The study hypothesizes that NBO therapy will improve erythropoiesis, reduce oxidative stress, and enhance immune function in CRC patients, leading to improved quality of life and clinical outcomes. Conclusions: Findings from this trial may establish NBO as a novel supportive therapy for CRC patients undergoing chemotherapy. Full article

Background: The retina, a light-sensitive tissue of the central nervous system that is located at the posterior part of the eye, is particularly vulnerable to alterations in oxygen levels. In various retinal diseases, such as central retinal vein occlusion, glaucoma, and diabetic retinopathy, hypoxia (a condition of low oxygen levels) is commonly observed. Müller glia, the principal glial cells in the retina, play a crucial role in supporting the metabolic needs of retinal neurons. They are also responsible for sensing oxygen levels and, in response to hypoxia, express Hypoxia-Inducible Factor 1 (HIF-1), a transcription factor that activates signaling pathways related to hypoxia. Methods: In this study, primary rat Müller glial cells were cultured and exposed to a 1% oxygen for 72 h. Following this, immunohistochemical assays were conducted to assess the effects of hypoxia on various parameters, including HIF-1α expression, cell survival, Müller glia-specific markers (CRALBP and GS), gliosis (GFAP expression), apoptosis (caspase-3 expression), cell proliferation (Ki-67 expression), and metabolic stress (indicated by the number of mitochondria per cell). Results: Under hypoxic conditions, a decrease in Müller glial survival and proliferation was observed. Conversely, there was an increase in HIF-1α expression, GFAP expression, caspase-3-positive cells, and the number of mitochondria per cell. However, no significant changes were noted in the expression of the Müller glial markers GS and CRALBP. Conclusions: In conclusion, hypoxia resulted in reduced proliferation and survival of Müller glial cells, primarily due to increased apoptosis and heightened metabolic stress. Full article

Background: Bladder cancer ranks ninth among the most commonly diagnosed cancers, with urothelial carcinoma (UC) accounting for more than 90% of all cases. Given the high recurrence rate and progression risk of bladder cancer, investigating alternative adjunct therapies is imperative. One potential candidate is isoliensinine, which has shown antitumor potential in various cancers; however, the effectiveness of isoliensinine on UC is largely unknown. Methods: In the present study, the effects of isoliensinine on UC cells were examined in a variety of in vitro experiments, including MTT assays, colony formation assays, flow cytometry assays, RNA sequencing analysis, and Western blotting. Results: The isoliensinine-treated T24 and UMUC3 UC cell lines showed cell growth inhibition and proliferation in the MTT and colony formation assays and an apoptotic effect in the flow cytometry assays. RNA sequencing analysis, performed to explain the underlying mechanisms, revealed a significant regulation of cell functions, including apoptosis, the cell cycle, hypoxia-inducible factor 1 (HIF-1) signaling, tumor necrosis factor (TNF) signaling, and ferroptosis. Subsequent Western blotting results verified all these findings. Conclusions: Overall, our data indicate that isoliensinine inhibits UC cell growth and proliferation by inducing apoptosis through alterations in the TNF and HIF1 pathways and ferroptosis. Overall, isoliensinine shows potential for use in new or combined adjunct therapies for the treatment of bladder cancer. Full article

Bone marrow stimulation is a treatment for articular cartilage injuries that promotes cartilage repair by inducing the migration and accumulation of mesenchymal stem cells (MSCs), but often results in fibrocartilage with limited durability. This study aimed to investigate the effect of hypoxic conditions on cartilage repair using a rat osteochondral defect model. Osteochondral defects (1.0 mm in diameter) were created in the femoral trochlear groove, and rats were exposed to hypoxic conditions (12% O₂) for 4 weeks postoperatively. Histological analysis was performed, and protein expression of hypoxia-inducible factor-1α (HIF-1α) and SRY-box transcription factor 9 (SOX9) in the repair tissue was evaluated after 1 week. As a result, after 1 week, protein expression of HIF-1α and SOX9 in the Hypoxia group was significantly increased compared to the Normoxia group. After 4 weeks, the Hypoxia group exhibited a hyaline cartilage-like tissue structure with a significantly lower Modified Wakitani score compared to the Normoxia group. Furthermore, after 4 weeks, the inhibition of HIF-1α suppressed cartilage repair. These findings suggest that hypoxic conditions promote SOX9 expression via HIF-1α during the early phase of MSC chondrogenic differentiation and promote the formation of hyaline cartilage-like repair tissue. In conclusion, bone marrow stimulation under hypoxic conditions may enhance the repair effect on articular cartilage injuries. Full article

Phytochemical investigation and bioactivity evaluation of terpenoids from the Croton species were conducted. The chemical composition of C. sylvaticus was explored using chemical phytochemical screening techniques and dereplication of ¹³C NMR data using MixONat software (v. 1.0.1). Natural products with diverse structural features were identified in the dichloromethane extract of trunk bark. These include monoterpenoids, sesquiterpenoids, diterpenoids, triterpenoids, along with other minor metabolites, such as steroids, saponins, and fatty acids. Further purification of this extract led to the isolation of three major secondary metabolites, acetyl aleuritolic acid, caryophyllene oxide, and phytol. These secondary metabolites were reported for the first time in C. sylvaticus. The isolated compounds were structurally compared to known anticancer terpenoids previously identified in two other Congolese Croton species. Through molecular docking studies, the predicted binding affinities of the identified compounds were assessed, and possible structure–activity relationships (SAR) were proposed. Two structurally characterized receptors—the human androgen receptor (HAR, PDB ID: 1E3G) and hypoxia-inducible factor 1-alpha (HIF-1α, PDB ID: 3KCX), known for their involvement in cancer-related pathways, were used for molecular docking investigations. Among the tested compounds, 1, 2, 3, and 12 were identified as having strong-to-moderate predicted binding affinities to both protein targets, along with favorable drug-like properties according to the ADMET analysis. This investigation could justify the use of Croton plants in traditional medicine. In addition, our study highlights the potential of the Congolese Croton species as sources of bioactive secondary metabolites. Full article

Background/Objectives: In the tumor microenvironment, hypoxia regulates genes that support tumor cell invasion and angiogenesis under the control of the hypoxia-inducible transcription factors (HIFs). Pleiotrophin (PTN) is a secreted protein that activates cell migration in endothelial and cancer cells that express α_νβ₃ integrin but has inhibitory effects in cells that do not express α_νβ₃ integrin. In both cases, the protein tyrosine phosphatase receptor zeta 1 (PTPRZ1) seems to mediate the effects of PTN. In the present work, we studied the effect of hypoxia on PTN and PTPRZ1 expression and the functional consequences of this effect. Methods: Western blot, quantitative real-time PCR, and luciferase assays were used to study the impact of hypoxia at the protein, mRNA, and transcriptional levels, respectively. Decoy oligonucleotides (ODNs), siRNA technology, and plasmid overexpression were used to study the involvement of the transcription factors studied. Functional assays were used to study the effect of hypoxia on cell proliferation and migration. Results: Hypoxia increases PTN expression through the transcriptional activation of the corresponding gene in α_νβ₃ integrin-expressing cells. The transcription factors HIF-1α, HIF-2α, and AP-1 mediate the up-regulation of PTN by hypoxia. Functional assays in endothelial cells from PTN knockout mice or endothelial and cancer cells following the downregulation of PTN expression showed that PTN negatively affects chemical hypoxia-induced cell proliferation and migration. In cancer cells that do not express α_νβ₃ integrin, hypoxia or chemical hypoxia inhibits PTN expression in a HIF-1α-, HIF-2α-, and AP-1-independent manner. The expression of PTPRZ1 is up-regulated by chemical hypoxia, is HIF-1α- and HIF-2α-dependent, and seems to limit the activation of HIF-1α, at least in endothelial cells. Conclusions: Hypoxia or chemical hypoxia regulates PTN and PTPRZ1 expressions to restrict the stimulatory effects of hypoxia on endothelial and cancer cell migration. Full article

Glioblastoma (GBM) is a highly aggressive and malignant brain tumor, characterized by hypoxia in its microenvironment, which drives its growth and resistance to treatments. Hypoxia-inducible factor 1 (HIF-1) plays a central role in GBM progression by regulating cellular adaptation to low oxygen availability, promoting processes such as angiogenesis and cell invasion. However, studying and modeling GBM under hypoxic conditions is complex, especially due to the limitations of animal models. In this study, we developed a glioma spheroid model using an alginate–gelatin hydrogel scaffold, which enabled the simulation of hypoxic conditions within the tumor. The scaffold-based model demonstrated high reproducibility, facilitating the analysis of HIF-1α expression, a key protein in the hypoxic response of GBM. Furthermore, cell viability, the microstructural features of the encapsulated spheroids, and the water absorption rate of the hydrogel were assessed. Our findings validate the three-dimensional (3D) glioblastoma spheroids model as a valuable platform for studying hypoxia in GBM and evaluating new therapies. This approach could offer a more accessible and specific alternative for studying the tumor microenvironment and therapeutic resistance in GBM. Full article

Osteoporosis is a prevalent metabolic bone disorder characterized by decreased bone mineral density and increased fracture risk, particularly among aging populations. While conventional pharmacological treatments exist, they often have adverse effects, necessitating the search for alternative therapies. Resveratrol, a naturally occurring polyphenol, has gained significant attention for its potential osteoprotective properties through various molecular mechanisms. This systematic review aims to comprehensively analyze the molecular pathways through which resveratrol protects against osteoporosis. Using an advanced search strategy in the Scopus, PubMed, and Web of Science databases, we identified 513 potentially relevant articles. After title and abstract screening, followed by full-text review, 28 studies met the inclusion criteria. The selected studies comprised 14 in vitro studies, 8 mixed in vitro and in vivo studies, 6 in vivo studies, and 1 cross-sectional study in postmenopausal women. Our findings indicate that resveratrol exerts its osteoprotective effects by enhancing osteoblast differentiation through the activation of the Phosphoinositide 3-Kinase/Protein Kinase B (PI3K/Akt), Sirtuin 1 (SIRT1), AMP-Activated Protein Kinase (AMPK), and GATA Binding Protein 1 (GATA-1) pathways while simultaneously inhibiting osteoclastogenesis by suppressing Mitogen-Activated Protein Kinase (MAPK) and TNF Receptor-Associated Factor 6/Transforming Growth Factor-β-Activated Kinase 1 (TRAF6/TAK1). Additionally, resveratrol mitigates oxidative stress and inflammation-induced bone loss by activating the Hippo Signaling Pathway/Yes-Associated Protein (Hippo/YAP) and Nuclear Factor Erythroid 2-Related Factor 2 (NRF2) pathways and suppressing Reactive Oxygen Species/Hypoxia-Inducible Factor-1 Alpha (ROS/HIF-1α) and NADPH Oxidase 4/Nuclear Factor Kappa-Light-Chain-Enhancer of Activated B Cells (Nox4/NF-κB). Despite promising preclinical findings, the low bioavailability of resveratrol remains a significant challenge, highlighting the need for novel delivery strategies to improve its therapeutic potential. This review provides critical insights into the molecular mechanisms of resveratrol in bone health, supporting its potential as a natural alternative for osteoporosis prevention and treatment. Further clinical studies are required to validate its efficacy and establish optimal dosing strategies. Full article

Smooth muscle cells (SMCs) are an essential component of the intestine, play an important role to maintain intestine structure, and produce peristaltic and segmentation movements. The silent information regulator 1 (SIRT1) has a dual role along with possible mechanisms in the different experimental models of inflammatory bowel disease (IBD). However, very little is known about other putative roles that overexpression of SIRT1 in SMCs may have. Here, we explored the role of SMC SIRT1 in colonic mucosa regeneration and recovery after DSS-induced colitis. We showed that smooth-muscle-specific SIRT1 transgene (Sirt1-Tg) mice have abnormal baseline intestinal architecture. The overexpression of SIRT1 impaired the recovery after DSS-induced injury. Furthermore, we showed that smooth-muscle SIRT1 affected the intestinal epithelial regeneration after damage by releasing cZFP609, which inhibited the hypoxia-inducible factor (HIF)-1α nuclear translocation. Together, we identify an important signaling axis cZFP609-HIF-1α linking SMCs and intestinal epithelium, which is involved in colitis development. Full article

Background: Lung cancer remains the leading cause of cancer-related deaths worldwide, with non-small cell lung carcinomas (NSCLCs) comprising the majority of cases. Among the common driver mutations, KRAS plays a critical role in guiding treatment strategies. This study evaluates the expression of programmed death-ligand 1 (PD-L1) and hypoxia-inducible factor 1-alpha (HIF-1α) in KRAS-mutant NSCLCs and investigates their associations with clinicopathological findings. Methods: A total of 85 cases with KRAS mutations were analyzed. Immunohistochemical staining for HIF-1α and PD-L1 was performed, and their relationships with mutation status and prognostic variables were assessed. Results: A significant correlation was identified between HIF-1α expression and PD-L1 expression in tumor cells. While the KRAS G12C mutation was not significantly associated with HIF-1α expression in tumor cells, it demonstrated a notable relationship with HIF-1α expression in the tumor microenvironment and PD-L1 expression. However, PD-L1 and HIF-1α expression did not significantly influence overall survival outcomes. Conclusions: Expression of PD-L1 was positively correlated with HIF-1α, which may provide evidence for a novel therapy targeting PD-L1 and HIF-1α in NSCLC. Further comprehensive studies are warranted to elucidate the prognostic implications of tumor–microenvironment and mutation interactions. Full article

The prevalence and deaths from esophageal cancer (EC) have recently increased. Although therapeutic strategies depend on the EC stage and recurrence, such as surgical intervention, chemotherapy, radiation therapy, chemoradiation therapy, targeted therapy, and immunotherapy, a more effective and novel treatment for EC is still required. This review briefly describes and summarizes some insightful oncotargets involved in the metabolic modulation of EC, including (1) cancer stem cells (CSCs) for EC progression, poor prognosis, tumor recurrence, and therapy resistance; (2) retinoic acid receptors (RARs) for esophageal carcinogenesis and regeneration; (3) phosphofructokinase (PFK) for EC-reprogrammed glycolysis; (4) lactate dehydrogenase (LDH) as an EC peripheral blood biomarker; and (5) hypoxia-inducible factor-1 alpha (HIF-1α) for the tumor microenvironment under hypoxic conditions. Moreover, the aforementioned oncotargets can be modulated by mutant TP53 and have their own features in the carcinogenesis, differentiation, proliferation, and metastasis of EC. Thus, the clarification of pharmacological mechanisms regarding the interaction between mutant TP53 and the abovementioned oncotargets could provide precise and perspective opinions for minimizing prediction errors, reducing therapy resistance, and developing novel drugs against EC. Full article

Background/Objectives: Hypoxia-inducible factor-1α (HIF-1α) is a transcription factor that plays a crucial role in various physiological and pathological processes of the ovary. However, the timing of HIF-1α expression and its specific biological function in the follicular development of the human ovary remain unclear. Therefore, in this study, we aimed to examine whether HIF-1α and its downstream gene, N-myc downstream-regulated gene 1 (NDRG1), exhibit stage-specific expression during the follicular development process in the human ovary. Methods: We used ovarian tissues from eight women with regular menstrual cycles who were not undergoing hormonal treatment. We investigated HIF-1α and NDRG1 expression and localization using immunohistochemistry. Further, we transfected human ovarian granulosa (KGN) cells with HIF-1α small interfering RNA (siRNA) to investigate the influence of HIF-1α on NDRG1 expression and progesterone synthesis. Results: The immunohistochemical analysis of human ovarian tissues revealed that HIF-1α was localized in the cytoplasm of granulosa cells (GCs) at both the primary and secondary follicular stages. Conversely, in tertiary and later developmental stages, HIF-1α was observed exclusively in the nucleus of GCs. Furthermore, while NDRG1 was not detected in primary follicles, it was present in all GCs beyond the tertiary stage. Notably, transfection of KGN cells with HIF-1α siRNA significantly decreased NDRG1 expression, at both the mRNA and protein levels, and in progesterone synthesis. Conclusion: Our results indicate that HIF-1α and NDRG1 are integral to follicular development and the early luteinization of pre-ovulatory follicles. Full article

Malic enzyme 1 (ME1) plays a key role in promoting malignant phenotypes in various types of cancer. ME1 promotes epithelial–mesenchymal transition (EMT) and enhances stemness via glutaminolysis, energy metabolism reprogramming from oxidative phosphorylation to glycolysis. As a result, ME1 promotes the malignant phenotypes of cancer cells and poor patient prognosis. In particular, ME1 expression is promoted in hypoxic environments associated with hypoxia-inducible factor (HIF1) α. ME1 is overexpressed in budding cells at the cancer invasive front, promoting cancer invasion and metastasis. ME1 also generates nicotinamide adenine dinucleotide (NADPH), which, together with glucose-6-phosphate dehydrogenase (G6PD) and isocitrate dehydrogenase (IDH1), expands the NADPH pool, maintaining the redox balance in cancer cells, suppressing cell death by neutralizing mitochondrial reactive oxygen species (ROS), and promoting stemness. This review summarizes the latest research insights into the mechanisms by which ME1 contributes to cancer progression. Because ME1 is involved in various aspects of cancer and promotes many of its malignant phenotypes, it is expected that ME1 will become a novel drug target in the near future. Full article