Cancer Cell Metabolism in Hypoxia: Role of HIF-1 as Key Regulator and Therapeutic Target

A hypoxia-derived gene signature to suggest cisplatin-based therapeutic responses in patients with cervical cancer

Cervical cancer remains a significant global public health concern, often exhibits cisplatin resistance in clinical settings. Hypoxia, a characteristic of cervical cancer, substantially contributes to cisplatin resistance. To evaluate the therapeutic efficacy of cisplatin in patients with cervical cancer and to identify potential effective drugs against cisplatin resistance, we established a hypoxia-inducible factor-1 (HIF-1)-related risk score (HRRS) model using clinical data from patients treated with cisplatin. Cox and LASSO regression analyses were used to stratify patient risks and prognosis. Through qRT-PCR, we validated nine potential prognostic HIF-1 genes that successfully predict cisplatin responsiveness in patients and cell lines. Subsequently, we identified fostamatinib, an FDA-approved spleen tyrosine kinase inhibitor, as a promising drug for targeting the HRRS-high group. We observed a positive correlation between the IC50 values of fostamatinib and HRRS in cervical cancer cell lines. Moreover, fostamatinib exhibited potent anticancer effects on high HRRS groups in vitro and in vivo. In summary, we developed a hypoxia-related gene signature that suggests cisplatin response prediction in cervical cancer and identified fostamatinib as a potential novel treatment approach for resistant cases.

Interplay between hypoxia inducible Factor-1 and mitochondria in cardiac diseases

Ischemic heart diseases and cardiomyopathies are characterized by hypoxia, energy starvation and mitochondrial dysfunction. HIF-1 acts as a cellular oxygen sensor, tuning the balance of metabolic and oxidative stress pathways to provide ATP and sustain cell survival. Acting on mitochondria, HIF-1 regulates different processes such as energy substrate utilization, oxidative phosphorylation and mitochondrial dynamics. In turn, mitochondrial homeostasis modifications impact HIF-1 activity. This underlies that HIF-1 and mitochondria are tightly interconnected to maintain cell homeostasis. Despite many evidences linking HIF-1 and mitochondria, the mechanistic insights are far from being understood, particularly in the context of cardiac diseases. Here, we explore the current understanding of how HIF-1, reactive oxygen species and cell metabolism are interconnected, with a specific focus on mitochondrial function and dynamics. We also discuss the divergent roles of HIF in acute and chronic cardiac diseases in order to highlight that HIF-1, mitochondria and oxidative stress interaction deserves to be deeply investigated. While the strategies aiming at stabilizing HIF-1 have provided beneficial effects in acute ischemic injury, some deleterious effects were observed during prolonged HIF-1 activation. Thus, deciphering the link between HIF-1 and mitochondria will help to optimize HIF-1 modulation and provide new therapeutic perspectives for the treatment of cardiovascular pathologies.

A new framework for novel analogues of pazopanib as potent and selective human carbonic anhydrase inhibitors: Design, repurposing rational, synthesis, crystallographic, in vivo and in vitro biological assessments

Herein, we describe the design and synthesis of novel aryl pyrimidine benzenesulfonamides APBSs 5a-n, 6a-c, 7a-b, and 8 as pazopanib analogues to explore new potent and selective inhibitors for the CA IX. All APBSs were examined in vitro for their promising inhibition activity against a small panel of hCAs (isoforms I, II, IX, and XII). The X-ray crystal structure of CA I in adduct with a representative APBS analogue was solved. APBS-5m, endowed with the best hCA IX inhibitory efficacy and selectivity, was evaluated for antiproliferative activity against a small panel of different cancer cell lines, SK-MEL-173, MDA-MB-231, A549, HCT-116, and HeLa, and it demonstrated one-digit IC50 values range from 2.93 μM (MDA-MB-231) to 5.86 μM (A549). Furthermore, compound APBS-5m was evaluated for its influence on hypoxia-inducible factor (HIF-1α) production, apoptosis induction, and colony formation in MDA-MB-231 cancer cells. The in vivo efficacy of APBS-5m as an antitumor agent was additionally investigated in an animal model of Solid Ehrlich Carcinoma (SEC). In order to offer perceptions into the conveyed hCA IX inhibitory efficacy and selectivity in silico, a molecular docking investigation was also carried out.

HIF-1 mediated metabolic reprogramming in cancer: Mechanisms and therapeutic implications

Cancer cells undergo metabolic reprogramming to survive in hypoxic conditions and meet the elevated energy demands of the cancer microenvironment. This metabolic alteration is orchestrated by hypoxia-inducible factor 1 (HIF-1), regulating various processes within cancer cells. The intricate metabolic modifications induced by hypoxia underscore the significance of HIF-1-induced metabolic reprogramming in promoting each aspect of cancer progression. The complex interactions between HIF-1 signalling and cellular metabolic processes in response to hypoxia are examined in this study, focusing on the metabolism of carbohydrates, nucleotides, lipids, and amino acids. Comprehending the various regulatory mechanisms controlled by HIF-1 in cellular metabolism sheds light on the intricate biology of cancer growth and offers useful insights for developing targeted treatments.

O-GlcNAc signaling: implications for stress-induced adaptive response pathway in the tumor microenvironment

The tumor microenvironment (TME) consists of tumor cells, non-tumor cells, extracellular matrix, and signaling molecules, which can contribute to tumor initiation, progression, and therapy resistance. In response to starvation, hypoxia, and drug treatments, tumor cells undergo a variety of deleterious endogenous stresses, such as hypoxia, DNA damage, and oxidative stress. In this context, to survive the difficult situation, tumor cells evolve multiple conserved adaptive responses, including metabolic reprogramming, DNA damage checkpoints, homologous recombination, up-regulated antioxidant pathways, and activated unfolded protein responses. In the last decades, the protein O-GlcNAcylation has emerged as a crucial causative link between glucose metabolism and tumor progression. Here, we discuss the relevant pathways that regulate the above responses. These pathways are adaptive adjustments induced by endogenous stresses in cells. In addition, we systematically discuss the role of O-GlcNAcylation-regulated stress-induced adaptive response pathways (SARPs) in TME remodeling, tumor progression, and treatment resistance. We also emphasize targeting O-GlcNAcylation through compounds that modulate OGT or OGA activity to inhibit tumor progression. It seems that targeting O-GlcNAcylated proteins to intervene in TME may be a novel approach to improve tumor prognosis.

Molecular mechanism of anticancer effect of heat shock protein 90 inhibitor BIIB021 in human bladder cancer cell line

Bladder cancer is a type of urologic malignancy that exhibits significant morbidity, mortality, and treatment costs. Inhibition of heat shock protein 90 (HSP90) activity has been a promising pharmacological strategy for blocking of bladder cancer pathogenesis. BIIB021 is a next-generation HSP90 inhibitor which interrupts ATP hydrolysis process of HSP90 and inhibits the stabilization and correct folding of client proteins. In current study, we aimed to investigate the molecular mechanism of the anticancer activity of BIIB021 in human bladder cancer T24 cells. Our results revealed that nanomolar concentration of BIIB021 decreased viability of T24 cell. BIIB021 downregulated HSP90 expression in T24 cells and inhibited the refolding activity of luciferase in the presence of T24 cell lysate. PCR array data indicated a significant alteration in transcript levels of cancer-related genes involved in metastases, apoptotic cell death, cell cycle, cellular senescence, DNA damage and repair mechanisms, epithelial-to-mesenchymal transition, hypoxia, telomeres and telomerase, and cancer metabolism pathways in T24 cells. All findings hypothesize that BIIB021 could exhibit as effective HSP90 inhibitor in the future for treatment of bladder cancer patients.

Manipulation of protein corona for nanomedicines

Nanomedicines have significantly advanced the development of diagnostic and therapeutic strategies for various diseases, while they still encounter numerous challenges. Upon entry into the human body, nanomedicines interact with biomolecules to form a layer of proteins, which is defined as the protein corona that influences the biological properties of nanomedicines. Traditional approaches have primarily focused on designing stealthy nanomedicines to evade biomolecule adsorption; however, due to the intricacies of the biological environment within body, this method cannot completely prevent biomolecule adsorption. As research on the protein corona progresses, manipulating the protein corona to modulate the in vivo behaviors of nanomedicines has become a research focus. In this review, modern strategies focused on influencing the biological efficacy of nanomedicines in vivo by manipulating protein corona, along with their wide-ranging applications across diverse diseases are critically summarized, highlighted and discussed. Finally, future directions for this important yet challenging research area are also briefly discussed. This article is categorized under: Nanotechnology Approaches to Biology > Nanoscale Systems in Biology Therapeutic Approaches and Drug Discovery > Emerging Technologies Biology-Inspired Nanomaterials > Protein and Virus-Based Structures.

Cancer EV stimulate endothelial glycolysis to fuel protein synthesis via mTOR and AMPKα activation

Hypoxia is a common feature of solid tumours and activates adaptation mechanisms in cancer cells that induce therapy resistance and has profound effects on cellular metabolism. As such, hypoxia is an important contributor to cancer progression and is associated with a poor prognosis. Metabolic alterations in cells within the tumour microenvironment support tumour growth via, amongst others, the suppression of immune reactions and the induction of angiogenesis. Recently, extracellular vesicles (EV) have emerged as important mediators of intercellular communication in support of cancer progression. Previously, we demonstrated the pro-angiogenic properties of hypoxic cancer cell derived EV. In this study, we investigate how (hypoxic) cancer cell derived EV mediate their effects. We demonstrate that cancer derived EV regulate cellular metabolism and protein synthesis in acceptor cells through increased activation of mTOR and AMPKα. Using metabolic tracer experiments, we demonstrate that EV stimulate glucose uptake in endothelial cells to fuel amino acid synthesis and stimulate amino acid uptake to increase protein synthesis. Despite alterations in cargo, we show that the effect of cancer derived EV on recipient cells is primarily determined by the EV producing cancer cell type rather than its oxygenation status.

The cellular-centered view of hypoxia tumor microenvironment: Molecular mechanisms and therapeutic interventions

Cancer is a profoundly dynamic, heterogeneous and aggressive systemic ailment, with a coordinated evolution of various types of tumor niches. Hypoxia plays an indispensable role in the tumor micro-ecosystem, drastically enhancing the plasticity of cancer cells, fibroblasts and immune cells and orchestrating intercellular communication. Hypoxia-induced signals, particularly hypoxia-inducible factor-1α (HIF-1α), drive the reprogramming of genetic, transcriptional, and proteomic profiles. This leads to a spectrum of interconnected processes, including augmented survival of cancer cells, evasion of immune surveillance, metabolic reprogramming, remodeling of the extracellular matrix, and the development of resistance to conventional therapeutic modalities like radiotherapy and chemotherapy. Here, we summarize the latest research on the multifaceted effects of hypoxia, where a multitude of cellular and non-cellular elements crosstalk with each other and co-evolve in a synergistic manner. Additionally, we investigate therapeutic approaches targeting hypoxic niche, encompassing hypoxia-activated prodrugs, HIF inhibitors, nanomedicines, and combination therapies. Finally, we discuss some of the issues to be addressed and highlight the potential of emerging technologies in the treatment of cancer.

Malate dehydrogenase (MDH) in cancer: a promiscuous enzyme, a redox regulator, and a metabolic co-conspirator

Malate dehydrogenase (MDH) is an essential enzyme in the tricarboxylic acid cycle that functions in cellular respiration and redox homeostasis. Recent studies indicate that MDH facilitates metabolic plasticity in tumor cells, catalyzing the formation of an oncometabolite, contributing to altered epigenetics, and maintaining redox capacity to support the rewired energy metabolism and biosynthesis that enables cancer progression. This minireview summarizes current findings on the unique supporting roles played by MDH in human cancers and provides an update on targeting MDH in cancer chemotherapy.

Hypoxia-induced activation of HIF-1alpha/IL-1beta axis in microglia promotes glioma progression via NF-κB-mediated upregulation of heparanase expression

BACKGROUND

Glioma is a common tumor that occurs in the brain and spinal cord. Hypoxia is a crucial feature of the tumor microenvironment. Tumor-associated macrophages/microglia play a crucial role in the advancement of glioma. This study aims to illuminate the detailed mechanisms by which hypoxia regulates microglia and, consequently, influences the progression of glioma.

METHODS

The glioma cell viability and proliferation were analyzed by cell counting kit-8 assay and 5-ethynyl-2'-deoxyuridine assay. Wound healing assay and transwell assay were implemented to detect glioma cell migration and invasion, respectively. Enzyme-linked immunosorbent assay was conducted to detect protein levels in cell culture medium. The protein levels in glioma cells and tumor tissues were evaluated using western blot analysis. The histological morphology of tumor tissue was determined by hematoxylin-eosin staining. The protein expression in tumor tissues was determined using immunohistochemistry. Human glioma xenograft in nude mice was employed to test the influence of hypoxic microglia-derived interleukin-1beta (IL-1β) and heparanase (HPSE) on glioma growth in vivo.

RESULTS

Hypoxic HMC3 cells promoted proliferation, migration, and invasion abilities of U251 and U87 cells by secreting IL-1β, which was upregulated by hypoxia-induced activation of hypoxia inducible factor-1alpha (HIF-1α). Besides, IL-1β from HMC3 cells promoted glioma progression and caused activation of nuclear factor-κB (NF-κB) and upregulation of HPSE in vivo. We also confirmed that IL-1β facilitated HPSE expression in U251 and U87 cells by activating NF-κB. Hypoxic HMC3 cells-secreted IL-1β facilitated the proliferation, migration, and invasion of U251 and U87 cells via NF-κB-mediated upregulation of HPSE expression. Finally, we revealed that silencing HPSE curbed the proliferation and metastasis of glioma in mice.

CONCLUSION

Hypoxia-induced activation of HIF-1α/IL-1β axis in microglia promoted glioma progression via NF-κB-mediated upregulation of HPSE expression.

Macrophages as Targets in Hepatocellular Carcinoma Therapy

Hepatocellular carcinoma (HCC) is a malignant tumor with a complex and diverse immunosuppressive microenvironment. Tumor-associated macrophages (TAM) are an essential component of the tumor immune microenvironment. TAMs typically exist in two primary states: anti-tumor M1 macrophages and protumor M2 macrophages. Remarkably, TAMs possess high plasticity, enabling them to switch between different subtypes or alter their biological functions in response to the tumor microenvironment. Based on research into the biological role of TAMs in the occurrence and development of malignant tumors, including HCC, TAMs are emerging as promising targets for novel tumor treatment strategies. In this review, we provide a detailed introduction to the origin and subtypes of TAMs, elucidate their interactions with other cells in the complex tumor microenvironment of HCC, and describe the biological roles, characteristics, and mechanisms of TAMs in the progression of HCC. Furthermore, we furnish an overview of the latest therapeutic strategies targeting TAMs.

Study on the mechanism of heterogeneous tumor-associated macrophages in three subtypes of breast cancer through the integration of single-cell RNA sequencing and in vitro experiments

BACKGROUND

Tumor-associated macrophages (TAM) exert a significant influence on the progression and heterogeneity of various subtypes of breast cancer (BRCA). However, the roles of heterogeneous TAM within BRCA subtypes remain unclear. Therefore, this study sought to elucidate the role of TAM across the following three BRCA subtypes: triple-negative breast cancer, luminal, and HER2.

MATERIALS AND METHODS

This investigation aimed to delineate the variations in marker genes, drug sensitivity, and cellular communication among TAM across the three BRCA subtypes. We identified specific ligand-receptor (L-R) pairs and downstream mechanisms regulated by VEGFA-VEGFR1, SPP1-CD44, and SPP1-ITGB1 L-R pairs. Experimental verification of these pairs was conducted by co-culturing macrophages with three subtypes of BRCA cells.

RESULTS

Our findings reveal the heterogeneity of macrophages within the three BRCA subtypes, evidenced by variations in marker gene expression, composition, and functional characteristics. Notably, heterogeneous TAM were found to promote invasive migration and epithelial-mesenchymal transition (EMT) in MDA-MB-231, MCF-7, and SKBR3 cells, activating NF-κB pathway via P38 MAPK, TGF-β1, and AKT, respectively, through distinct VEGFA-VEGFR1, SPP1-CD44, and SPP1-ITGB1 L-R pairs. Inhibition of these specific L-R pairs effectively reversed EMT, migration, and invasion of each cancer cells. Furthermore, we observed a correlation between ligand gene expression and TAM sensitivity to anticancer drugs, suggesting a potential strategy for optimizing personalized treatment guidance.

CONCLUSION

Our study highlights the capacity of heterogeneous TAM to modulate biological functions via distinct pathways mediated by specific L-R pairs within diverse BRCA subtypes. This study might provide insights into precision immunotherapy of different subtypes of BRCA.

Network pharmacology to explore the mechanism of traditional Chinese medicine in the treatment of ground glass nodules

Background

Ground glass nodules (GGNs) in the lung are considered to be a high-risk factor of lung adenocarcinoma. Immediate surgery is not recommended for GGNs patients, and low-dose computed tomography (CT) is often used for observation and follow-up, which brings high psychological and economic burden to the patient.

Methods

Three traditional Chinese medicine (TCM) prescriptions for the treatment of GGNs were found through database including PubMed, Google Scholar, and China National Knowledge Infrastructure (CNKI), Scopus and so on. The possible targets of the active ingredients of the TCM preparations and the gene targets of GGNs were screened out from Traditional Chinese Medicine Systems Pharmacology (TCMSP), UniProt and GeneCards. Network visualization was realized via STRING, Cytoscape 3.7.2, Evenn, DAVID and Hiplot. Finally, molecular docking Vina and PyMOL software were performed to further explore the possibility of drug-target interactions using PubChem compounds, protein data bank (PDB) database, Autodocktools and Autodock.

Results

Three TCM preparations could target the same 13 potential therapeutic targets in GGNs. From network pharmacology, 14 signaling pathways, the functions of the significant targets, an effective ingredient in TCM prescriptions and its functions were obtained.

Conclusions

Chinese herbal formulas containing quercetin could be a potential treatment for GGNs, targeting C-reactive protein (CRP), tumor necrosis factor (TNF), interferon gamma (IFN-γ), intercellular adhesion molecule 1 (ICAM-1), and vascular endothelial growth factor A (VEGFA) through the hypoxia-inducible factor 1 (HIF-1) pathway, mitogen-activated protein kinase (MAPK) signaling pathway, and leukocyte transendothelial migration.

The PI3K/Akt Pathway and Glucose Metabolism: A Dangerous Liaison in Cancer

Aberrant activation of the PI3K/Akt pathway commonly occurs in cancers and correlates with multiple aspects of malignant progression. In particular, recent evidence suggests that the PI3K/Akt signaling plays a fundamental role in promoting the so-called aerobic glycolysis or Warburg effect, by phosphorylating different nutrient transporters and metabolic enzymes, such as GLUT1, HK2, PFKB3/4 and PKM2, and by regulating various molecular networks and proteins, including mTORC1, GSK3, FOXO transcription factors, MYC and HIF-1α. This leads to a profound reprogramming of cancer metabolism, also impacting on pentose phosphate pathway, mitochondrial oxidative phosphorylation, de novo lipid synthesis and redox homeostasis and thereby allowing the fulfillment of both the catabolic and anabolic demands of tumor cells. The present review discusses the interactions between the PI3K/Akt cascade and its metabolic targets, focusing on their possible therapeutic implications.

Identification of candidate plasma miRNA biomarkers for the diagnosis of head and neck squamous cell carcinoma

Aim: Current head and neck squamous cell carcinoma (HNSCC) diagnostic tools are limited, so this study aimed to identify diagnostic microRNA (miRNA) biomarkers from plasma. Materials & methods: A total of 76 HNSCC and 76 noncancerous control (NC) plasma samples underwent microarray analysis and quantitative reverse transcription PCR to screen for diagnostic plasma miRNAs. The diagnostic potential of the miRNAs was evaluated by the receiver operating characteristic curve. Results: miR-95-3p and miR-579-5p expression was shown to be significantly upregulated, and that of miR-1298-3p to be downregulated in HNSCC patients compared with controls. The final diagnostic panel included miR-95-3p, miR-579-5p and miR-1298-3p with an area under the curve of 0.83. Conclusion: This three-miRNA panel has potential for the diagnosis of HNSCC.

Targeting the autophagy-miRNA axis in prostate cancer: toward novel diagnostic and therapeutic strategies

Since prostate cancer is one of the leading causes of cancer-related death, a better understanding of the molecular pathways guiding its development is imperative. A key factor in prostate cancer is autophagy, a cellular mechanism that affects both cell survival and death. Autophagy is essential in maintaining cellular homeostasis. Autophagy is a physiological mechanism wherein redundant or malfunctioning cellular constituents are broken down and recycled. It is essential for preserving cellular homeostasis and is implicated in several physiological and pathological conditions, including cancer. Autophagy has been linked to metastasis, tumor development, and treatment resistance in prostate cancer. The deregulation of miRNAs related to autophagy appears to be a crucial element in the etiology of prostate cancer. These miRNAs influence the destiny of cancer cells by finely regulating autophagic mechanisms. Numerous investigations have emphasized the dual function of specific miRNAs in prostate cancer, which alter autophagy-related pathways to function as either tumor suppressors or oncogenes. Notably, miRNAs have been linked to the control of autophagy and the proliferation, apoptosis, and migration of prostate cancer cells. To create customized therapy approaches, it is imperative to comprehend the dynamic interplay between autophagy and miRNAs in prostate cancer. The identification of key miRNAs provides potential diagnostic and prognostic markers. Unraveling the complex network of lncRNAs, like PCA3, also expands the repertoire of molecular targets for therapeutic interventions. This review explores the intricate interplay between autophagy and miRNAs in prostate cancer, focusing on their regulatory roles in cellular processes ranging from survival to programmed cell death.

Fasting-induced RNF152 resensitizes gallbladder cancer cells to gemcitabine by inhibiting mTORC1-mediated glycolysis

Abnormal mTORC1 activation by the lysosomal Ragulator complex has been implicated in cancer and glycolytic metabolism associated with drug resistance. Fasting upregulates RNF152 and mediates the metabolic status of cells. We report that RNF152 regulates mTORC1 signaling by targeting a Ragulator subunit, p18, and attenuates gemcitabine resistance in gallbladder cancer (GBC). We detected levels of RNF152 and p18 in tissues and undertook mechanistic studies using activators, inhibitors, and lentivirus transfections. RNF152 levels were significantly lower in GBC than in adjacent non-cancer tissues. Fasting impairs glycolysis, induces gemcitabine sensitivity, and upregulates RNF152 expression. RNF152 overexpression increases the sensitivity of GBC cells to gemcitabine, whereas silencing RNF152 has the opposite effect. Fasting-induced RNF152 ubiquitinates p18, resulting in proteasomal degradation. RNF152 deficiency increases the lysosomal localization of p18 and increases mTORC1 activity, to promote glycolysis and decrease gemcitabine sensitivity. RNF152 suppresses mTORC1 activity to inhibit glycolysis and enhance gemcitabine sensitivity in GBC.

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.

3-Hydroxytanshinone Inhibits the Activity of Hypoxia-Inducible Factor 1-α by Interfering with the Function of α-Enolase in the Glycolytic Pathway

Tumor cells in hypoxic conditions control cancer metabolism and angiogenesis by expressing HIF-1α. Tanshinone is a traditional Chinese medicine that has been shown to possess antitumor properties and exerts a therapeutic impact on angiogenesis. However, the precise molecular mechanism responsible for the antitumor activity of 3-Hydroxytanshinone (3-HT), a type of tanshinone, has not been fully understood. Therefore, our study aimed to investigate the mechanism by which 3-HT regulates the expression of HIF-1α. Our findings demonstrate that 3-HT inhibits HIF-1α activity and expression under hypoxic conditions. Additionally, 3-HT inhibits hypoxia-induced angiogenesis by suppressing the expression of VEGF. Moreover, 3-HT was found to directly bind to α-enolase, an enzyme associated with glycolysis, resulting in the suppression of its activity. This inhibition of α-enolase activity by 3-HT leads to the blockade of the glycolytic pathway and a decrease in glycolysis products, ultimately altering HIF1-α expression. Furthermore, 3-HT negatively regulates the expression of HIF-1α by altering the phosphorylation of AMP-activated protein kinase (AMPK). Our study's findings elucidate the mechanism by which 3-HT regulates HIF-1α through the inhibition of the glycolytic enzyme α-enolase and the phosphorylation of AMPK. These results suggest that 3-HT holds promise as a potential therapeutic agent for hypoxia-related angiogenesis and tumorigenesis.

Identification of hypoxia-induced metabolism-associated genes in canine tumours

Canine tumours including urothelial carcinoma, lung adenocarcinoma, mammary gland tumour, squamous cell carcinoma, and melanoma have been identified as causes of death, but effective therapies are limited due to insufficient knowledge of the molecular mechanisms involved. Within the tumour microenvironment, hypoxia activates hypoxia-inducible factor 1α (HIF1α) in tumour cells. High HIF1α expression correlates with enhanced glycolysis and poorer outcomes in human cancers. However, the molecular mechanisms underlying hypoxic tumour cells remain elusive in dogs. In our study, we investigated upregulated genes in a canine malignant melanoma cell line during hypoxia using RNA-sequencing analysis. Glycolysis and HIF1 signalling pathways were upregulated in hypoxic melanoma cells. HIF1α knockout melanoma cells revealed that the glycolysis marker MCT4 is regulated by HIF1α activation. Hypoxia induces high lactate secretion due to enhanced glycolysis in canine melanoma cells. Furthermore, we examined monocarboxylate transporter 4 (MCT4) expression in malignant melanoma and eight other types of canine tumour tissues using immunohistochemistry (IHC). Membrane-localized MCT4 protein was mostly detected in urothelial carcinoma and lung adenocarcinoma rather than malignant melanoma. We conclude that canine MCT4 protein plays a role in lactic acid efflux from glycolytic cells and may serve as a marker for hypoxia and glycolysis in canine tumours. These findings could inform future therapeutic strategies targeting MCT4.

Cell-Membrane-Coated Metal-Organic Framework Nanocarrier Combining Chemodynamic Therapy for the Inhibition of Hepatocellular Carcinoma Proliferation

Chemodynamic therapy (CDT) employs hydrogen peroxide (H2O2) within the tumor microenvironment (TME) to initiate the Fenton reaction and catalyze the generation of hydroxyl radicals (·OH) for targeted therapy. Metal ion-based nanomaterials have garnered significant attention as catalysts due to their potent anti-tumor effects. Hypoxia in the TME is often associated with cancer cell development and metastasis, with HIF-1α being a pivotal factor in hypoxia adaptation. In this study, an organic framework called MIL-101 (Fe) was designed and synthesized to facilitate H2O2-induced ·OH production while also serving as a carrier for the HIF-1α inhibitor Acriflavine (ACF). A biomimetic nanomedical drug delivery system named MIL-101/ACF@CCM was constructed by encapsulating liver cancer cell membranes onto the framework. This delivery system utilized the homologous targeting of tumor cell membranes to transport ACF, inhibiting HIF-1α expression, alleviating tumor hypoxia, and catalyzing ·OH production for effective tumor eradication. Both in vivo and in vitro experiments confirmed that combining ACF with chemotherapy achieved remarkable tumor inhibition by enhancing ROS production and suppressing HIF-1α expression.

Revealing the Causal Impact of Obstructive Sleep Apnea on Cancer Risk: Insights from Mendelian randomization analysis

BACKGROUND

Observational studies have suggested that obstructive sleep apnea (OSA) may have a potential carcinogenic role. However, the results of these studies were inconsistent and the underlying genetic mechanisms have yet to be fully understood.

METHODS

We conducted a Mendelian randomization (MR) analysis using large-scale genome-wide association studies summary statistics to explore the possible causal effect of OSA on the risk of 16 specific-site cancers in the European population.

RESULTS

The MR analysis revealed a significantly negative correlation between OSA and the susceptibility to prostate cancer (OR: 0.87, 95%CI 0.79-0.95, p = 0.002) and a causal increase in the vulnerability to pancreatic malignancies (OR: 2.02, 95%CI 1.1-3.7, p = 0.02). However, no causal effects of OSA on other specific-site cancers were found. Sensitivity analyses demonstrated no significant heterogeneity or horizontal pleiotropy, thus validating the robustness of the original results.

CONCLUSION

Our MR provided important insights into the causal associations between OSA and cancer risk, highlighting both protective and potentially harmful effects of OSA on different cancer types.

Combining fecal microbiome and metabolomics reveals diagnostic biomarkers for esophageal squamous cell carcinoma

Esophageal squamous cell carcinoma (ESCC) is one of the most predominant subtypes of esophageal cancer. The characteristics of the gut microbiome and its metabolites from patients with ESCC have not been adequately studied and discussed. In this study, 40 fecal samples (20 from ESCC patients and 20 from healthy controls) were analyzed by 16S rRNA gene sequencing and untargeted metabolomics. The data sets were analyzed individually and synthesized using various bioinformatics methods. Alpha and beta diversity indicated significant differences in microbial diversity and abundance between ESCC and healthy control feces. At the genus level, the abundance of Phascolarctobacterium, Sutterella, and Streptococcus was significantly increased in ESCC. At the genus level, linear discriminant analysis effect size identified two biomarkers: Bacteroides_stercoris and Prevotella_copri. Untargeted metabolomics analysis revealed 307 differential metabolites between ESCC and healthy control feces, with indoles and derivatives, tropane alkaloids, lipids, and lipid-like molecules in higher relative abundance in ESCC feces than in healthy control feces. Kyoto Encyclopedia of Genes and Genomes enrichment analysis revealed that unsaturated fatty acids (FAs), ascorbate and aldarate metabolism, and hypoxia-inducible factor 1 signaling pathway were significantly associated with differential metabolite. Phenylethanolamine and despropionyl p-fluoro fentanyl could be used as reliable biomarkers to differentiate ESCC from healthy control. The correlation analysis showed that Prevotella may be involved in the synthesis of fatty acyl, carboxylic acids and derivatives, benzenes and substituted derivatives, organic oxygenates, and indoles and derivatives as metabolites. Fusicatenibacter and Lachnospira may be involved in the degradation of indoles and derivatives. Alistipes, Agathobacter, and Parabacteroides may be involved in the synthesis of indoles and derivatives with strong contributions. There is an intricate relationship between the gut microbiome and the levels of several metabolites (e.g., fatty acyls, carboxylic acids and derivatives, indoles, and derivatives). Microbial-associated metabolites can be used as diagnostic biomarkers in therapeutic exploration. Further analysis revealed that Prevotella, Alistipes, Agathobacter, and Parabacteroides might promote ESCC by regulating the synthesis of indoles and their derivatives. The results of this study provide favorable evidence for the early diagnosis of ESCC and subsequent individualized treatment and targeted interventions.IMPORTANCEWe describe for the first time the differences in fecal microbiome composition and metabolites between patients with esophageal squamous cell carcinoma (ESCC) and healthy controls by 16S rRNA gene sequencing and untargeted metabolomics. The results of this study provide a favorable basis for the early diagnosis of ESCC and subsequent targeted interventional therapy.

EPAS1, a hypoxia- and ferroptosis-related gene, promotes malignant behaviour of cervical cancer by ceRNA and super-enhancer

Hypoxia and Ferroptosis are associated with the malignant behaviour of cervical cancer. Endothelial PAS domain-containing protein 1 (EPAS1) contributes to the progression of cervical cancer. EPAS1 plays important roles in hypoxia and ferroptosis. Using the GEO dataset, machine-learning algorithms were used to screen for hypoxia- and ferroptosis-related genes (HFRGs) in cervical cancer. EPAS1 was identified as the hub gene. qPCR and WB were used to investigate the expression of EPAS1 in normal and cervical cancer tissues. The proliferation, invasion and migration of EPAS1 cells in HeLa and SiHa cell lines were detected using CCK8, transwell and wound healing assays, respectively. Apoptosis was detected by flow cytometry. A dual-luciferase assay was used to analyse the MALAT1-miR-182-5P-EPAS1 mRNA axis and core promoter elements of the super-enhancer. EPAS1 was significantly overexpressed in cervical cancer tissues. EPAS1 could increase the proliferation, invasion, migration of HeLa and SiHa cells and reduce the apoptosis of HeLa and SiHa cell. According to the double-luciferase assay, EPAS1 expression was regulated by the MALAT1-Mir-182-5p-EPAS1 mRNA axis. EPAS1 is associated with super-enhancers. Double-luciferase assay showed that the core elements of the super-enhancer were E1 and E3. EPAS1, an HFRG, is significantly overexpressed in cervical cancer. EPAS1 promotes malignant behaviour of cervical cancer cells. EPAS1 expression is regulated by super-enhancers and the MALAT1-miR-182-5P- EPAS1 mRNA axis. EPAS1 may be a target for the diagnosis and treatment of cervical cancer.

Metabolic Roles of HIF1, c-Myc, and p53 in Glioma Cells

The metabolic reprogramming that promotes tumorigenesis in glioblastoma is induced by dynamic alterations in the hypoxic tumor microenvironment, as well as in transcriptional and signaling networks, which result in changes in global genetic expression. The signaling pathways PI3K/AKT/mTOR and RAS/RAF/MEK/ERK stimulate cell metabolism, either directly or indirectly, by modulating the transcriptional factors p53, HIF1, and c-Myc. The overexpression of HIF1 and c-Myc, master regulators of cellular metabolism, is a key contributor to the synthesis of bioenergetic molecules that mediate glioma cell transformation, proliferation, survival, migration, and invasion by modifying the transcription levels of key gene groups involved in metabolism. Meanwhile, the tumor-suppressing protein p53, which negatively regulates HIF1 and c-Myc, is often lost in glioblastoma. Alterations in this triad of transcriptional factors induce a metabolic shift in glioma cells that allows them to adapt and survive changes such as mutations, hypoxia, acidosis, the presence of reactive oxygen species, and nutrient deprivation, by modulating the activity and expression of signaling molecules, enzymes, metabolites, transporters, and regulators involved in glycolysis and glutamine metabolism, the pentose phosphate cycle, the tricarboxylic acid cycle, and oxidative phosphorylation, as well as the synthesis and degradation of fatty acids and nucleic acids. This review summarizes our current knowledge on the role of HIF1, c-Myc, and p53 in the genic regulatory network for metabolism in glioma cells, as well as potential therapeutic inhibitors of these factors.

Lipid Peroxidation-Related Redox Signaling in Osteosarcoma

Oxidative stress and lipid peroxidation play important roles in numerous physiological and pathological processes, while the bioactive products of lipid peroxidation, lipid hydroperoxides and reactive aldehydes, act as important mediators of redox signaling in normal and malignant cells. Many types of cancer, including osteosarcoma, express altered redox signaling pathways. Such redox signaling pathways protect cancer cells from the cytotoxic effects of oxidative stress, thus supporting malignant transformation, and eventually from cytotoxic anticancer therapies associated with oxidative stress. In this review, we aim to explore the status of lipid peroxidation in osteosarcoma and highlight the involvement of lipid peroxidation products in redox signaling pathways, including the involvement of lipid peroxidation in osteosarcoma therapies.

The ras-related protein RAB22A interacts with hypoxia-inducible factor 1-alpha (HIF-1α) in MDA-MB-231 breast cancer cells in hypoxia

BACKGROUND

Recent studies suggest that hypoxia-inducible factor 1-alpha (HIF-1α) and the small GTPase protein Ras-related protein Rab-22 A (RAB22A) may be colocalized in the cytoplasm and that as a conequence they may enhance the formation of microvesicles in breast cancer cells under hypoxia. Therefore, we sought to determine whether these two proteins are present in intracellular complexes in breast carcinoma cells.

METHODS AND RESULTS

Evaluation using molecular docking indicated that HIF-1α and RAB22A interact with each other. Co-immunoprecipitation of endogenous or ectopically expressed HIF-1α and RAB22A proteins in MDA-MB-231 breast cancer cells or HEK-293T cells demonstrated that endogenous HIF-1α and RAB22A can form an intracellular complex; however, transiently expressed HIF-1α and RAB22A failed to interact. Investigating RAB22A and HIF-1α interactions in various cancer cell lines under hypoxia may shed light on their roles in cancer cell survival and progression through regulation of intracellular trafficking by HIF-1α under hypoxic conditions.

CONCLUSIONS

Our study is the first to reveal the potential involvement of HIF-1α in intracellular trafficking through physical interactions with the small GTPase protein RAB22A. We discuss the implications of our work on the role of exosomes and microvesicles in tumor invasiveness.

Hypoxia-associated markers in the prognosis of oral canine melanoma

Canine oral malignant melanoma (COMM) is the most common neoplasm in the oral cavity characterized by local invasiveness and high metastatic potential. Hypoxia represents a crucial feature of the solid tumor microenvironment promoting cancer progression and drug resistance. Hypoxia-inducible factor-1α (HIF-1α) and its downstream effectors, vascular endothelial growth factor A (VEGF-A), glucose transporter isoform 1 (GLUT1), C-X-C chemokine receptor type 4 (CXCR4), and carbonic anhydrase IX (CAIX), are the main regulators of the adaptive response to low oxygen availability. The prognostic value of these markers was evaluated in 36 COMMs using immunohistochemistry. In addition, the effects of cobalt chloride-mediated hypoxia were evaluated in 1 primary COMM cell line. HIF-1α expression was observed in the nucleus, and this localization correlated with the presence or enhanced expression of HIF-1α-regulated genes at the protein level. Multivariate analysis revealed that in dogs given chondroitin sulfate proteoglycan-4 (CSPG4) DNA vaccine, COMMs expressing HIF-1α, VEGF-A, and CXCR4 were associated with shorter disease-free intervals (DFI) compared with tumors that were negative for these markers (P = .03), suggesting hypoxia can influence immunotherapy response. Western blotting showed that, under chemically induced hypoxia, COMM cells accumulate HIF-1α and smaller amounts of CAIX. HIF-1α induction and stabilization triggered by hypoxia was corroborated by immunofluorescence, showing its nuclear translocation. These findings reinforce the role of an hypoxic microenvironment in tumor progression and patient outcome in COMM, as previously established in several human and canine cancers. In addition, hypoxic markers may represent promising prognostic markers, highlighting opportunities for their use in therapeutic strategies for COMMs.

Genetic loss of Nrf1 and Nrf2 leads to distinct metabolism reprogramming of HepG2 cells by opposing regulation of the PI3K-AKT-mTOR signalling pathway

As a vital hallmarker of cancer, the metabolic reprogramming has been shown to play a pivotal role in tumour occurrence, metastasis and drug resistance. Amongst a vast variety of signalling molecules and metabolic enzymes involved in the regulation of cancer metabolism, two key transcription factors Nrf1 and Nrf2 are required for redox signal transduction and metabolic homeostasis. However, the regulatory effects of Nrf1 and Nrf2 (both encoded by Nfe2l1 and Nfe2l2, respectively) on the metabolic reprogramming of hepatocellular carcinoma cells have been not well understood to date. Here, we found that the genetic deletion of Nrf1 and Nrf2 from HepG2 cells resulted in distinct metabolic reprogramming. Loss of Nrf1α led to enhanced glycolysis, reduced mitochondrial oxygen consumption, enhanced gluconeogenesis and activation of the pentose phosphate pathway in the hepatocellular carcinoma cells. By striking contrast, loss of Nrf2 attenuated the glycolysis and gluconeogenesis pathways, but with not any significant effects on the pentose phosphate pathway. Moreover, knockout of Nrf1α also caused fat deposition and increased amino acid synthesis and transport, especially serine synthesis, whilst Nrf2 deficiency did not cause fat deposition, but attenuated amino acid synthesis and transport. Further experiments revealed that such distinctive metabolic programming of between Nrf1α-/- and Nrf2-/- resulted from substantial activation of the PI3K-AKT-mTOR signalling pathway upon the loss of Nrf1, leading to increased expression of critical genes for the glucose uptake, glycolysis, the pentose phosphate pathway, and the de novo lipid synthesis, whereas deficiency of Nrf2 resulted in the opposite phenomenon by inhibiting the PI3K-AKT-mTOR pathway. Altogether, these provide a novel insight into the cancer metabolic reprogramming and guide the exploration of a new strategy for targeted cancer therapy.

Transcriptional Responses of Different Brain Cell Types to Oxygen Decline

Brain hypoxia is associated with a wide range of physiological and clinical conditions. Although oxygen is an essential constituent of maintaining brain functions, our understanding of how specific brain cell types globally respond and adapt to decreasing oxygen conditions is incomplete. In this study, we exposed mouse primary neurons, astrocytes, and microglia to normoxia and two hypoxic conditions and obtained genome-wide transcriptional profiles of the treated cells. Analysis of differentially expressed genes under conditions of reduced oxygen revealed a canonical hypoxic response shared among different brain cell types. In addition, we observed a higher sensitivity of neurons to oxygen decline, and dissected cell type-specific biological processes affected by hypoxia. Importantly, this study establishes novel gene modules associated with brain cells responding to oxygen deprivation and reveals a state of profound stress incurred by hypoxia.

Effects of hypoxia on the growth of gastric cancer and the chemotherapeutic efficacy of 5-fluorouracil

OBJECTIVES

Hypoxia is an important cause of chemotherapy resistance in gastric cancer. However, little is known about the growth of gastric cancer under purely hypoxia conditions. This study aims to study the effect of hypoxia on the growth patterns of gastric cancer cells and explore the response of gastric cancer cells to the chemotherapeutic drug 5-fluorouracil (5-FU) in a hypoxic environment.

METHODS

Gastric cancer cells MKN45 were cultured under 1% oxygen hypoxia and conventional air conditions. An intervention group with the addition of the chemotherapeutic drug 5-FU was also established. The proliferation and apoptosis of gastric cancer cells under different oxygen conditions and intervention groups were detected using the cell counting kit-8 (CCK-8) method, JC-1 mitochondrial membrane potential assay, and Annexin-V/PI double staining method. Cell cycle changes were detected by flow cytometry, and mitochondrial changes were detected using electron microscopy.

RESULTS

In the absence of 5-FU intervention, compared with the normoxia group, the hypoxia group showed higher rates of early and late apoptosis and higher cell death rates as indicated by the JC-1 mitochondrial membrane potential assay, Annexin-V/PI double staining, and CCK-8 results. Flow cytometry results showed that the cell cycle was arrested in the G0/G1 phase without progression. Electron microscopy revealed more severe mitochondrial destruction. However, with 5-FU intervention, the hypoxia group showed lower apoptosis rates, more cell cycle progression, and less mitochondrial destruction compared with the normoxia group.

CONCLUSIONS

Hypoxic environments promote apoptosis and even death in gastric cancer cells, but hypoxia counteracts the efficacy of the chemotherapeutic drug 5-FU, which may contribute to 5-FU chemotherapy resistance.

Marine-Derived Leads as Anticancer Candidates by Disrupting Hypoxic Signaling through Hypoxia-Inducible Factors Inhibition

The inadequate vascularization seen in fast-growing solid tumors gives rise to hypoxic areas, fostering specific changes in gene expression that bolster tumor cell survival and metastasis, ultimately leading to unfavorable clinical prognoses across different cancer types. Hypoxia-inducible factors (HIF-1 and HIF-2) emerge as druggable pivotal players orchestrating tumor metastasis and angiogenesis, thus positioning them as prime targets for cancer treatment. A range of HIF inhibitors, notably natural compounds originating from marine organisms, exhibit encouraging anticancer properties, underscoring their significance as promising therapeutic options. Bioprospection of the marine environment is now a well-settled approach to the discovery and development of anticancer agents that might have their medicinal chemistry developed into clinical candidates. However, despite the massive increase in the number of marine natural products classified as 'anticancer leads,' most of which correspond to general cytotoxic agents, and only a few have been characterized regarding their molecular targets and mechanisms of action. The current review presents a critical analysis of inhibitors of HIF-1 and HIF-2 and hypoxia-selective compounds that have been sourced from marine organisms and that might act as new chemotherapeutic candidates or serve as templates for the development of structurally similar derivatives with improved anticancer efficacy.

Hypoxia rewires glucose and glutamine metabolism in different sources of skeletal stem and progenitor cells similarly, except for pyruvate

Skeletal stem and progenitor cells (SSPCs) are crucial for bone development, homeostasis, and repair. SSPCs are considered to reside in a rather hypoxic niche in the bone, but distinct SSPC niches have been described in different skeletal regions, and they likely differ in oxygen and nutrient availability. Currently it remains unknown whether the different SSPC sources have a comparable metabolic profile and respond in a similar manner to hypoxia. In this study, we show that cell proliferation of all SSPCs was increased in hypoxia, suggesting that SSPCs can indeed function in a hypoxic niche in vivo. In addition, low oxygen tension increased glucose consumption and lactate production, but affected pyruvate metabolism cell-specifically. Hypoxia decreased tricarboxylic acid (TCA) cycle anaplerosis and altered glucose entry into the TCA cycle from pyruvate dehydrogenase to pyruvate carboxylase and/or malic enzyme. Finally, a switch from glutamine oxidation to reductive carboxylation was observed in hypoxia, as well as cell-specific adaptations in the metabolism of other amino acids. Collectively, our findings show that SSPCs from different skeletal locations proliferate adequately in hypoxia by rewiring glucose and amino acid metabolism in a cell-specific manner.

Network pharmacology and experimental verification study on the mechanism of Hedyotis diffusa Willd in treating colorectal cancer

This study aimed to evaluate the pharmacological mechanism of Hedyotis diffusa Willd against CRC (colorectal cancer) using network pharmacological analysis combined with experimental validation. The active components and potential targets of Hedyotis diffusa Willd were screened from the tax compliance management program public database using network pharmacology. The core anti-CRC targets were screened using a protein-protein interaction (PPI) network. The mRNA and protein expression of core target genes in normal colon and CRC tissues and their relationship with overall CRC survival were evaluated using The Cancer Genome Atlas (TCGA), Human Protein Atlas (HPA), and Gene Expression Profiling Interactive Analysis (GEPIA) databases. Functional and pathway enrichment analyses of the potential targets were performed using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG). The first six core targets with stable binding were molecular-docked with the active components quercetin and β-sitosterol. Finally, the results of network pharmacology were verified using in vitro experiments. In total, 149 potential targets were identified by searching for seven types of active components and the intersection of all potential and CRC targets. PPI network analysis showed that ten target genes, including tumor protein p53 (TP53) and recombinant cyclin D1 (CCND1), were pivotal genes. GO enrichment analysis involved 2043 biological processes, 52 cellular components, and 191 molecular functions. KEGG enrichment analysis indicated that the anticancer effects of H. alba were mediated by tumor necrosis factor, interleukin-17, and nuclear factor-κB (NF-κB) signaling pathways. Validation of key targets showed that the validation results for most core genes were consistent with those in this study. Molecular docking revealed that the ten core target proteins could be well combined with quercetin and β-sitosterol and the structure remained stable after binding. The results of the in vitro experiment showed that β-sitosterol inhibited proliferation and induced apoptosis in SW620 cells. This study identified a potential target plant for CRC through network pharmacology and in vitro validation.

Metastatic potentials classified with hypoxia-inducible factor 1 downstream genes in pan-cancer cell lines

Hypoxia-inducible factor 1 (HIF1) is a transcription factor that is stabilized under hypoxia conditions via post-translational modifications. HIF1 regulates tumor malignancy and metastasis by gene transcriptions, such as Warburg effect and angiogenesis-related genes, in cancer cells. However, the HIF1 downstream genes show varied expressional patterns in different cancer types. Herein, we performed the hierarchical clustering based on the HIF1 downstream gene expression patterns using 1406 cancer cell lines crossing 30 types of cancer to understand the relationship between HIF1 downstream genes and the metastatic potential of cancer cell lines. Two types of cancers, including bone and breast cancers, were classified based on HIF1 downstream genes with significantly altered metastatic potentials. Furthermore, different HIF1 downstream gene subsets were extracted to discriminate each subtype for these cancer types. HIF1 downstream subtyping classification will help to understand the novel insight into tumor malignancy and metastasis in each cancer type.

Effect of long-term treatment with trivalent chromium on erythropoietin production in HepG2 cells

Trivalent chromium (Cr(III)) is sometimes taken as a long-term supplement, but its effectiveness is unclear. Recently, Cr(III) reportedly modulates peroxisome proliferator-activated receptor gamma (PPARγ) expression. Our previous study reported that increased PPARγ after 24 h Cr(III) treatment promoted erythropoietin (EPO) production in HepG2 cells. In the current study, we analyzed 4-week Cr(III) treatment effects on PPARγ and EPO production in HepG2 cells. Long-term Cr(III) treatment resulted in significantly elevated mRNA expression levels of PPARγ and EPO compared to controls. Additionally, treatment with a PPARγ inhibitor suppressed EPO mRNA expression. Increased EPO mRNA expression due to stimulation with hypoxia or cobalt was unaffected by long-term Cr(III) treatment. Administration of lipopolysaccharide and pyocyanin which causes oxidative stress, promoted EPO production, but this effect was attenuated in cells treated with Cr(III). Long-term Cr(III) treatment increased hypoxia inducible factor (HIF)-1α and 2α mRNA expression and protein levels. Increased PPARγ, induced by long-term Cr(III) treatment, suppressed sirtuin1 (SIRT1) mRNA expression and increased EPO mRNA expression, suggesting that increased PPARγ attenuated the suppressive effect of SIRT1 on HIF. These results suggest that the sustained increase in PPARγ during long-term Cr(III) treatment maintains increased EPO production through a mechanism different from that observed under hypoxia.

Targeting Hypoxia-Inducible Factor-1 (HIF-1) in Cancer: Emerging Therapeutic Strategies and Pathway Regulation

Hypoxia-inducible factor-1 (HIF-1) is a key regulator for balancing oxygen in the cells. It is a transcription factor that regulates the expression of target genes involved in oxygen homeostasis in response to hypoxia. Recently, research has demonstrated the multiple roles of HIF-1 in the pathophysiology of various diseases, including cancer. It is a crucial mediator of the hypoxic response and regulator of oxygen metabolism, thus contributing to tumor development and progression. Studies showed that the expression of the HIF-1α subunit is significantly upregulated in cancer cells and promotes tumor survival by multiple mechanisms. In addition, HIF-1 has potential contributing roles in cancer progression, including cell division, survival, proliferation, angiogenesis, and metastasis. Moreover, HIF-1 has a role in regulating cellular metabolic pathways, particularly the anaerobic metabolism of glucose. Given its significant and potential roles in cancer development and progression, it has been an intriguing therapeutic target for cancer research. Several compounds targeting HIF-1-associated processes are now being used to treat different types of cancer. This review outlines emerging therapeutic strategies that target HIF-1 as well as the relevance and regulation of the HIF-1 pathways in cancer. Moreover, it addresses the employment of nanotechnology in developing these promising strategies.

Emerging therapies targeting growth factors in hepatocellular carcinoma

INTRODUCTION

Hepatocellular carcinoma (HCC) is a primary liver cancer that commonly arises in the background of chronic liver inflammation and/or cirrhosis. Chronic liver inflammation results in the production of different growth factors, remodeling of the microenvironment architecture into fibrosis, and eventually carcinogenesis. Overexpression of some growth factors has been associated with worse prognosis in patients with HCC. Targeted therapies against growth factors may disrupt cell signaling and the mechanisms that allow for cell survival (e.g. angiogenesis, proliferation, metastases).

AREAS COVERED

We herein review potential growth factor targets of HCC and the limited research that exists regarding targeted therapy of these ligands and their receptors. We performed an extensive literature search to investigate preclinical studies, clinical research, and clinical trials.

EXPERT OPINION

Systemic therapy for patients with HCC is continuing to evolve. Anti-angiogenic therapy holds the most promise among targeted therapy for growth factors among patients with HCC. Improving our understanding of growth factors in HCC will hopefully lead to the development of new targeted therapies and strategies for combination therapies with immune checkpoint inhibitors.

HIF-1A as a prognostic biomarker related to invasion, migration and immunosuppression of cervical cancer

Background

The incidence of cervical cancer ranks second among malignant tumors in women, exerting a significant impact on their quality of life and overall well-being. The hypoxic microenvironment plays a pivotal role in the initiation and progression of tumorigenesis. The present study aims to investigate the fundamental genes and pathways associated with the hypoxia-inducible factor (HIF-1A) in cervical cancer, aiming to identify potential downstream targets for diagnostic and therapeutic purposes.

Methods

We obtained dataset GSE63514 from the Comprehensive Gene Expression Database (GEO). The dataset comprised of 24 patients in the normal group and 28 patients in the tumor group. Gene set difference analysis (GSVA) and gene set enrichment analysis (GSEA) were used to identify the genes related to HIF-1A expression and the specific signaling pathways involved.The association between HIF-1A and tumor immune infiltration was examined in the TCGA dataset. The WGCAN network was constructed to identify key genes within the blue module, and subsequent gene ontology (GO) function and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were conducted to determine the pathways and functional annotations associated with HIF-1A. The protein interaction network of the HIF-1A gene was obtained from the STRING database and visualized using Cytoscape in the meantime.The function of HIF-1A and its related gene expression were verified in vivo.

Results

HIF-1A was a risk factor in both univariate and multivariate Cox regression analysis of cervical cancer patients. A total of 344 genes significantly correlated with the expression of HIF-1A were identified through correlation analysis, and the genes exhibiting the strongest correlation were obtained. The major signaling pathways involved in HIF-1A encompass TNF-α/NF-κB, PI3K/AKT/MTOR, TGF-β, JAK-STAT, and various other signaling cascades. Reinforced by qRT-PCR, we identified Integrin beta-1 (ITGB1), C-C motif chemokine ligand 2 (CCL2), striatin 3 (STRN3), and endothelin-1 (EDN1) as pivotal downstream genes influenced by HIF-1A. HIF-1A is associated with immune infiltration of natural killer (NK) cells, mast cells, CD4+T cells, M0 macrophages, neutrophils, follicular helper T cells, CD8+T cells, and regulatory T cells (Treg). HIF-1A is associated with sensitivity to chemotherapy drugs. The identification of the HIF-1A pathway and its function primarily focuses on cytoplasmic translation, aerobic respiration, cellular respiration, oxidative phosphorylation, thermogenesis, among others. The results of in vivo experiments have confirmed that HIF-1A plays a crucial role in promoting the migration and invasion of cervical cancer cells. Moreover, the overexpression of HIF-1A led to an upregulation in the expressions of ITGB1, CCL2, STRN3, and EDN1.

Conclusions

The role of HIF-1A in cervical cancer was determined through a combination of bioinformatics analysis and experimental validation. The genes potentially implicated in the tumorigenesis mechanism of HIF-1A were identified. These findings has the potential to enhance our comprehension of the progression of cervical cancer and offer promising therapeutic targets for its clinical management.

Hypoxia inducible factor-1ɑ as a potential therapeutic target for osteosarcoma metastasis

Osteosarcoma (OS) is a malignant tumor originating from mesenchymal tissue. Pulmonary metastasis is usually present upon initial diagnosis, and metastasis is the primary factor affecting the poor prognosis of patients with OS. Current research shows that the ability to regulate the cellular microenvironment is essential for preventing the distant metastasis of OS, and anoxic microenvironments are important features of solid tumors. During hypoxia, hypoxia-inducible factor-1α (HIF-1α) expression levels and stability increase. Increased HIF-1α promotes tumor vascular remodeling, epithelial-mesenchymal transformation (EMT), and OS cells invasiveness; this leads to distant metastasis of OS cells. HIF-1α plays an essential role in the mechanisms of OS metastasis. In order to develop precise prognostic indicators and potential therapeutic targets for OS treatment, this review examines the molecular mechanisms of HIF-1α in the distant metastasis of OS cells; the signal transduction pathways mediated by HIF-1α are also discussed.

Clinical Potential of YY1-Hypoxia Axis for Vascular Normalization and to Improve Immunotherapy

Abnormal vasculature in solid tumors causes poor blood perfusion, hypoxia, low pH, and immune evasion. It also shapes the tumor microenvironment and affects response to immunotherapy. The combination of antiangiogenic therapy and immunotherapy has emerged as a promising approach to normalize vasculature and unlock the full potential of immunotherapy. However, the unpredictable and redundant mechanisms of vascularization and immune suppression triggered by tumor-specific hypoxic microenvironments indicate that such combination therapies need to be further evaluated to improve patient outcomes. Here, we provide an overview of the interplay between tumor angiogenesis and immune modulation and review the function and mechanism of the YY1-HIF axis that regulates the vascular and immune tumor microenvironment. Furthermore, we discuss the potential of targeting YY1 and other strategies, such as nanocarrier delivery systems and engineered immune cells (CAR-T), to normalize tumor vascularization and re-establish an immune-permissive microenvironment to enhance the efficacy of cancer therapy.

Tumor hypoxia and role of hypoxia-inducible factor in oral cancer

BACKGROUND

Head and neck cancer (HNC) is one of the most frequent malignancies in Asian males with a poor prognosis. Apart from well-known prognostic indicators, markers of tumor hypoxia can help us predict response to treatment and survival.

METHODS

A review of the literature on the present evidence and potential clinical importance of tumor hypoxia in head and neck cancer was carried out. The data obtained from the literature search is presented as a narrative review.

RESULTS

The literature shows possible associations between prognosis and low tumor oxygenation. Intermediate hypoxia biomarkers like HIF-1, GLUT-1, miRNA, and lactate, can help in predicting the response to therapy and survival as their altered expression is related to prognosis.

CONCLUSIONS

Hypoxia is common in HNC and can be detected by use of biomarkers. The tumors that show expression of hypoxia biomarkers have poor prognosis except for patients with human papilloma virus-associated or VHL-associated cancers. Therapeutic targeting of hypoxia is emerging; however, it is still in its nascent stage, with increasing clinical trials hypoxia is set to emerge as an attractive therapeutic target in HNC.

CRABP2 affects chemotherapy resistance of ovarian cancer by regulating the expression of HIF1α

Ovarian cancer is the most lethal malignancy among gynecologic cancers, and primary and secondary chemotherapy resistance is one of the important reasons for poor prognosis of ovarian cancer patients. However, the specifics of resistance to chemotherapy in ovarian cancer remain unclear. Herein, we find that the expression level of cellular retinoic acid binding protein 2 (CRABP2) is up-regulated in drug-resistant ovarian cancer tissues and cell lines, and the expression levels of CRABP2 in epithelial ovarian cancer tissues are closely related to tumor clinical stage and patients' prognosis, suggesting that CRABP2 plays an important role in the progression of ovarian cancer and the corresponding ability of tumor to chemotherapy. With the in-depth study, we demonstrates that CRABP2 is related to the high metabolic activity in drug-resistant cells, and all-trans retinoic acid exacerbates this activity. Further molecular mechanism exploration experiments show that CRABP2 not only up-regulates the expression level of HIF1α, but also increases the localization of HIF1α in the nucleus. In drug-resistant ovarian cancer cells, knocking down HIF1α can block the resistance of CRABP2 to chemotherapy drugs in ovarian cancer cells. Taken together, our findings suggest for the first time that CRABP2 affects chemotherapy resistance of ovarian cancer by regulating the expression of HIF1α. This study provides a possible molecular mechanism for drug resistance and a possible molecular target for clinical treatment of ovarian cancer.

The pathogenesis and regulatory role of HIF-1 in rheumatoid arthritis

Rheumatoid arthritis (RA) is a prevalent autoimmune disease that involves the overgrowth and inflammation of synovial tissue, leading to the degeneration and impairment of joints. In recent years, numerous studies have shown a close relationship between the hypoxic microenvironment in joints and the occurrence and progression of RA. The main cause of the pathological changes in RA is widely believed to be the abnormal expression of hypoxia-inducible factor-1 (HIF-1) in joints. This paper describes and illustrates the structure and primary functions of HIF-1 and explains the main regulatory methods of HIF-1, including the PHDs/HIF-1 α/pVHL pathway, factor-inhibiting HIF (FIH), regulation of inflammatory cytokines, and the NF-κB pathway. Furthermore, this paper discusses the mechanism of HIF-1 and its impact on inflammation, angiogenesis, and cartilage destruction in greater detail. We summarize previous research findings on the mechanism of HIF-1 and propose new potential treatments for RA based on the pathogenesis of HIF-1 in RA.

The APE1/REF-1 and the hallmarks of cancer

APE1/REF-1 (apurinic/apyrimidinic endonuclease 1 / redox factor-1) is a protein with two domains, with endonuclease function and redox activity. Its main activity described is acting in DNA repair by base excision repair (BER) pathway, which restores DNA damage caused by oxidation, alkylation, and single-strand breaks. In contrast, the APE1 redox domain is responsible for regulating transcription factors, such as AP-1 (activating protein-1), NF-κB (Nuclear Factor kappa B), HIF-1α (Hypoxia-inducible factor 1-alpha), and STAT3 (Signal Transducers and Activators of Transcription 3). These factors are involved in physiological cellular processes, such as cell growth, inflammation, and angiogenesis, as well as in cancer. In human malignant tumors, APE1 overexpression is associated with lung, colon, ovaries, prostate, and breast cancer progression, more aggressive tumor phenotypes, and worse prognosis. In this review, we explore APE1 and its domain's role in cancer development processes, highlighting the role of APE1 in the hallmarks of cancer. We reviewed original articles and reviews from Pubmed related to APE1 and cancer and found that both domains of APE1/REF-1, but mainly its redox activity, are essential to cancer cells. This protein is often overexpressed in cancer, and its expression and activity are correlated to processes such as proliferation, invasion, inflammation, angiogenesis, and resistance to cell death. Therefore, APE1 participates in essential processes of cancer development. Then, the activity of APE1/REF-1 in these hallmarks suggests that targeting this protein could be a good therapeutic approach.

Metabolomic Investigations into Hypoxia-Mediated Metabolic Reprogramming of Pancreatic Cancer Cells

Hypoxia is a crucial microenvironmental factor that defines tumor cell growth and aggressiveness. Cancer cells adapt to hypoxia by altering their metabolism. These alterations impact various cellular and physiological functions, including energy metabolism, vascularization, invasion and metastasis, genetic instability, cell immortalization, stem cell maintenance, and resistance to chemotherapy (Li et al. Technol Cancer Res Treat 20:15330338211036304, 2021). Hypoxia-inducible factor-1α (HIF-1α) is known to be a critical regulator of glycolysis that directly regulates the transcription of multiple key enzymes of the glycolysis pathway. Moreover, HIF-1α stabilization can be directly modulated by TCA-derived metabolites, including 2-ketoglutarate and succinate (Infantino et al, Int J Mol Sci 22(22), https://doi.org/10.3390/ijms22115703 , 2021). Overall, the molecular mechanisms underlying the adaptation of cellular metabolism to hypoxia impact the metabolic phenotype of cancer cells. Such adaptations include increased glucose uptake, increased lactate production, and increased levels of other metabolites that stabilize HIF-1α, leading to a vicious circle of hypoxia-induced tumor growth.

Expanding the ubiquitin code in pancreatic cancer

The ubiquitin-proteasome system (UPS) is a fundamental regulatory mechanism in cells, vital for maintaining cellular homeostasis, compiling signaling transduction, and determining cell fates. These biological processes require the coordinated signal cascades of UPS members, including ubiquitin ligases, ubiquitin-conjugating enzymes, deubiquitinases, and proteasomes, to ubiquitination and de-ubiquitination on substrates. Recent studies indicate that ubiquitination code rewriting is particularly prominent in pancreatic cancer. High frequency mutation or aberrant hyperexpression of UPS members dysregulates ferroptosis, tumor microenvironment, and metabolic rewiring processes and contribute to tumor growth, metastasis, immune evasion, and acquired drug resistance. We conduct an in-depth overview of ubiquitination process in pancreatic cancer, highlighting the role of ubiquitin code in tumor-promoting and tumor-suppressor pathways. Furthermore, we review current UPS modulators and analyze the potential of UPS modulators as cancer therapy.

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.

Hyperoxic-hypoxic Paradox: Breast Cancer Microenvironment and an Innovative Treatment Strategy

A small therapeutic range of oxygen is required for effective metabolism. As a result, hypoxia (low oxygen concentration) is one of the most potent inducers of gene expression, metabolic alterations, and regenerative processes, such as angiogenesis, stem cell proliferation, migration, and differentiation. The cellular response is controlled by sensing the increased oxygen levels (hyperoxia) or hypoxia via specific chemoreceptor cells. Surprisingly, changes in free oxygen concentration instead of absolute oxygen levels may be regarded as a deficiency of oxygen at the cellular level. Recurrent intermittent hyperoxia may trigger many mediators of cellular pathways typically generated during hypoxia. The dilemma of hyperoxic-hypoxic conditions is known as the hyperoxic-hypoxic paradox. According to the latest data, the hypoxic microenvironment, crucial during cancer formation, has been demonstrated to play a key role in regulating breast cancer growth and metastasis. Hypoxic circumstances cause breast cancer cells to respond in a variety of ways. Transcription factors are identified as hypoxia-inducible factors (HIFs) that have been suggested to be a factor in the pathobiology of breast cancer and a possible therapeutic target, driving the cellular response to hypoxia. Breast cancer has a dismal prognosis due to a high level of resistance to practically all well-known cancer management that has been related to hypoxia-based interactions between tumor cells and the stromal milieu. We attempt to review the enigma by exploring the starring roles of HIFs in breast cancer, the HIF paradox, and the hyperoxic-hypoxic enigma.