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23 pages, 2788 KB  
Article
Molecular Insights into the Synergistic Anticancer and Oxidative Stress–Modulating Activity of Quercetin and Gemcitabine
by Yasemin Afşin, Senem Alkan Akalın, İlhan Özdemir, Mehmet Cudi Tuncer and Şamil Öztürk
Antioxidants 2026, 15(1), 91; https://doi.org/10.3390/antiox15010091 - 10 Jan 2026
Viewed by 83
Abstract
Quercetin (Q), a bioactive flavonoid, exerts potent antioxidant and redox-modulating effects by activating the nuclear factor erythroid 2-related factor 2/antioxidant response Element (Nrf2/ARE) pathway and upregulating endogenous antioxidant defenses, including enzymatic antioxidants such as superoxide dismutase (SOD) and catalase (CAT), as well as [...] Read more.
Quercetin (Q), a bioactive flavonoid, exerts potent antioxidant and redox-modulating effects by activating the nuclear factor erythroid 2-related factor 2/antioxidant response Element (Nrf2/ARE) pathway and upregulating endogenous antioxidant defenses, including enzymatic antioxidants such as superoxide dismutase (SOD) and catalase (CAT), as well as non-enzymatic glutathione (GSH) and lipid peroxidation (MDA). Gemcitabine (Gem), a widely used antimetabolite chemotherapeutic, often shows limited efficacy under hypoxic and oxidative stress conditions driven by hypoxia-inducible factor 1-alpha (HIF-1α) and vascular endothelial growth factor (VEGF)-mediated angiogenesis. This study investigated the redox-mediated synergistic effects of Q and Gem in MDA-MB-231 human breast cancer cells. Combination treatment significantly reduced cell viability beyond the expected Bliss value, indicating a synergistic interaction and enhanced apoptosis compared with single-agent treatments. Increased reactive oxygen species (ROS) production was accompanied by depletion of GSH and accumulation of MDA, establishing a pro-apoptotic oxidative stress environment. Q alone enhanced SOD and CAT activities, whereas the combination induced exhaustion of antioxidant defenses under oxidative load, reflecting a redox-adaptive response. Molecular analyses revealed downregulation of HIF-1α and VEGF, alongside upregulation of Bax and Caspase-3, confirming suppression of hypoxia-driven survival and activation of the intrinsic apoptotic pathway. Transcriptomic and enrichment analyses further identified modulation of oxidative stress- and apoptosis-related pathways, including phosphoinositide-3-kinase–protein kinase B/Akt (PI3K/Akt), HIF-1 and VEGF signaling. Collectively, these results indicate that Q potentiates Gem cytotoxicity via redox modulation, promoting controlled ROS elevation and apoptosis while suppressing hypoxia-induced survival mechanisms, highlighting the therapeutic potential of redox-based combination strategies against chemoresistant breast cancer. Full article
(This article belongs to the Special Issue Redox Biomarkers in Cancer)
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28 pages, 3229 KB  
Article
Studies on the Complexation of Platinum(II) by Some 4-Nitroisothiazoles and the Cytotoxic Activity of the Resulting Complexes
by Andrzej Regiec, Joanna Wietrzyk, Magdalena Milczarek, Andrzej Kochel and Henryk Mastalarz
Molecules 2026, 31(1), 34; https://doi.org/10.3390/molecules31010034 - 22 Dec 2025
Viewed by 330
Abstract
Five novel platinum(II) complexes C1C5 were synthesized in the reaction of the appropriate substituted 4-nitroisothiazoles with K2PtCl4 and characterized with elemental analysis, ESI MS spectrometry, NMR spectroscopy, and IR spectroscopy. Also, a new methyl 3-methyl-4-nitroisothiazole-5-carboxylate (L2) [...] Read more.
Five novel platinum(II) complexes C1C5 were synthesized in the reaction of the appropriate substituted 4-nitroisothiazoles with K2PtCl4 and characterized with elemental analysis, ESI MS spectrometry, NMR spectroscopy, and IR spectroscopy. Also, a new methyl 3-methyl-4-nitroisothiazole-5-carboxylate (L2) was obtained. The structures of trans complex C4 and the new isothiazole derivative L2 were additionally confirmed by X-ray diffraction (XRD) method. The cytotoxicity of the investigated complexes was examined in vitro on three human cancer cell lines (MCF-7 breast, ES-2 ovarian, and A549 lung adenocarcinomas) in both normoxic and hypoxic conditions. The tested complexes, except for the most polar cisC5, which appeared to be the least active, showed cytotoxic activity comparable to that of the reference cisplatin. cis-complex C1, transC2, and transC3 showed slightly better cytotoxic activity than cisplatin against the MCF-7 cell line. The complexes had the weakest effect on the A549 cell line. No differences in the cytotoxic activity of the complexes were observed between normoxic and hypoxic conditions, except for the A549 cell line, where all the complexes, except for C2, were inactive in hypoxia. However, most complexes, including the reference cisplatin, were equally toxic to healthy BALB/3T3 cells and cancer cells. The trans complex C2 (isomeric to cisC1) showed even greater toxicity to healthy cells than to MCF-7 and A549 cancer cells. Some complexes were tested for stability against glutathione (GSH) solution to gain additional information that may facilitate the explanation of the pharmacological activity of the tested compounds. Additionally, some theoretical calculations on the thermochemistry of the complexation process were performed using quantum density functional theory (DFT), which indicate that complexation should occur through the coordination of the platinum cation by the nitrogen rather than the sulfur atom of the isothiazole ring. Full article
(This article belongs to the Special Issue Metal-Based Drugs: Past, Present and Future, 3rd Edition)
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22 pages, 3321 KB  
Article
Boswellic Acid Enhances Gemcitabine’s Inhibition of Hypoxia-Driven Angiogenesis in Human Endometrial Cancer
by Senem Alkan Akalın, Yasemin Afşin, İlhan Özdemir, Mehmet Cudi Tuncer and Şamil Öztürk
Medicina 2025, 61(12), 2181; https://doi.org/10.3390/medicina61122181 - 8 Dec 2025
Viewed by 332
Abstract
Background and Objectives: Endometrial carcinoma is among the most common gynecological malignancies, with recurrence and chemoresistance remaining major clinical challenges. This study aimed to evaluate the combined effects of Boswellic acid (BA), a natural pentacyclic triterpene, and Gemcitabine (GEM), a nucleoside analog [...] Read more.
Background and Objectives: Endometrial carcinoma is among the most common gynecological malignancies, with recurrence and chemoresistance remaining major clinical challenges. This study aimed to evaluate the combined effects of Boswellic acid (BA), a natural pentacyclic triterpene, and Gemcitabine (GEM), a nucleoside analog chemotherapeutic, on hypoxia, angiogenesis, and apoptosis in human endometrial cancer cells. Materials and Methods: ECC-1 cells were treated with BA, GEM, or their combination under normoxic and hypoxic conditions. Cell viability (MTT assay); nuclear morphology (NucBlue staining); cell cycle distribution (PI flow cytometry); angiogenesis (VEGF ELISA expression); apoptosis (Caspase-3/7 activity; Bax; Bcl-2 expression); inflammatory cytokines (IL-1β; IL-6; TNF-α); and gene ontology enrichment were analyzed. Results: Both BA and GEM reduced cell viability in a dose- and time-dependent manner, with the combination producing synergistic cytotoxicity and lower IC50 values. Hypoxia enhanced drug sensitivity, particularly in combination therapy. BA and GEM significantly suppressed HIF-1α and VEGF expression, with maximal inhibition observed in the combination group. Apoptotic induction was confirmed by increased Bax and Caspase-3 and decreased Bcl-2 expression, together with elevated Caspase-3/7, -8, and -9 activity. Pro-inflammatory cytokine levels were markedly reduced, and gene ontology analysis revealed enrichment of apoptotic, anti-proliferative, and anti-angiogenic pathways. Conclusions: BA + GEM combination synergistically suppresses hypoxia-driven angiogenesis and promotes apoptosis in endometrial cancer cells. These findings support its potential as an adjuvant therapeutic approach, warranting further preclinical and clinical validation. Full article
(This article belongs to the Special Issue Cancer Metabolism: Current Understanding and Therapies)
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16 pages, 3402 KB  
Article
Butylated Neuropeptide Antagonist Targeting Hypoxia-Induced GRPR Overexpression in Small Cell Lung Cancer
by Suttikiat Deureh, Amira M. Alghamdi, Ayşe Latif, Kaye J. Williams, Roben G. Gieling and Harmesh S. Aojula
Int. J. Mol. Sci. 2025, 26(21), 10786; https://doi.org/10.3390/ijms262110786 - 6 Nov 2025
Viewed by 672
Abstract
Small cell lung cancer (SCLC) is an aggressive neuroendocrine tumour with limited treatment options and a poor prognosis. Hypoxia, a hallmark of solid tumours, contributes to therapeutic resistance and tumour progression. Gastrin-releasing peptide receptor (GRPR) is known to be overexpressed in SCLC; however, [...] Read more.
Small cell lung cancer (SCLC) is an aggressive neuroendocrine tumour with limited treatment options and a poor prognosis. Hypoxia, a hallmark of solid tumours, contributes to therapeutic resistance and tumour progression. Gastrin-releasing peptide receptor (GRPR) is known to be overexpressed in SCLC; however, its regulation under hypoxic conditions is not well described. In this study, we demonstrate that hypoxia significantly enhances GRPR expression in SCLC cell lines, COR-L24 and DMS79, as confirmed by Western blot, immunofluorescence, and flow cytometric analysis of binding with fluorescein isothiocyanate–labelled bombesin (BBN-FITC), a known GRPR ligand. To exploit this upregulation, we synthesised a previously discovered butylated neuropeptide antagonist (BU peptide) using a new method of solid-phase peptide synthesis (SPPS) by Boc chemistry and evaluated its therapeutic potential. BU peptide exhibited potent, dose-dependent cytotoxicity in both cell lines, with significantly greater efficacy under hypoxic conditions compared to normoxia. Mechanistic studies revealed that BU peptide inhibits GRP–GRPR-mediated activation of the PI3K/Akt and MAPK/ERK signalling pathways, known to be key regulators of tumour cell survival and proliferation. Moreover, BU peptide induced robust caspase 3/7-mediated apoptosis, especially under hypoxic conditions. These findings suggest that GRPR is a hypoxia-inducible target in SCLC and demonstrate that a synthetically optimised BU peptide antagonist exerts selective efficacy against hypoxic tumour cells, outperforming conventional chemotherapy agents. These findings provide new mechanistic insights into SCLC and suggest translational potential to inform the development of future treatment strategies for this and other hypoxia-driven malignancies. Full article
(This article belongs to the Section Molecular Pharmacology)
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26 pages, 3114 KB  
Article
Targeting G6PD with Benzimidazole and Thiazole Derivatives Suppresses SIRT 2 and VEGF Expression and Induces Cytotoxicity in Glioma Cells
by Montserrat Vázquez-Bautista, Laura Morales-Luna, Verónica Pérez de la Cruz, Rosa Angélica Castillo-Rodríguez, José Antonio Velázquez-Aragón, Sergio Enríquez-Flores, Luis Antonio Flores-López, Elizabeth Hernández-Urzúa, Víctor Martínez-Rosas, Carlos Wong-Baeza, Isabel Baeza-Ramírez, Gabriel Navarrete-Vázquez, Benjamin Pineda, Beatriz Hernández-Ochoa and Saúl Gómez-Manzo
Int. J. Mol. Sci. 2025, 26(18), 9092; https://doi.org/10.3390/ijms26189092 - 18 Sep 2025
Viewed by 997
Abstract
Hypoxia and activation of the pentose phosphate pathway (PPP), as well as overexpression of glucose-6-phosphate dehydrogenase (G6PD), are hallmark features of glioblastomas (GBM), contributing significantly to tumor progression metabolic adaptation and drug resistance. This study aimed to evaluate the cytotoxic effects of nine [...] Read more.
Hypoxia and activation of the pentose phosphate pathway (PPP), as well as overexpression of glucose-6-phosphate dehydrogenase (G6PD), are hallmark features of glioblastomas (GBM), contributing significantly to tumor progression metabolic adaptation and drug resistance. This study aimed to evaluate the cytotoxic effects of nine synthetic compounds incorporating annulated benzimidazole and nitrothiazole scaffolds in two glioblastoma cell lines (A172 and U87-MG) under both normoxic and hypoxic conditions. Three compounds (BZM-7, BZM-9, and CNZ-3) demonstrated potent anticancer activity, with CNZ-3 exhibiting the highest efficacy, particularly in hypoxia. The study further investigated the effects of these compounds on the expression of the G6PD gene, as well as post-translational regulatory genes SIRT2 and KAT9, and the angiogenesis-related VEGF gene. Transcriptional analyses showed that the nitrothiazole-derived compound CNZ-3 significantly downregulated G6PD, SIRT2, KAT9 and VEGF expression under hypoxic conditions, suggesting selective interference with hypoxia-adaptative pathways. In contrast, BZM-7 and BZM-9 showed distinct expression patterns, indicating diverse mechanisms of action despite structural similarity. In addition, BZM-7, BZM-9, and CNZ-3 were identified as potent inhibitors of recombinant G6PD, demonstrating both enzymatic inhibition and structural alterations, suggesting that G6PD could be a relevant therapeutic target for these compounds. Furthermore, molecular docking analysis revealed favorable binding interactions between the compounds and key amino acids of the G6PD, reinforcing their potential as a direct enzyme inhibitors. These findings highlight the pivotal role of G6PD in gliomas under hypoxic conditions and support its inhibition as a promising therapeutic strategy. Full article
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18 pages, 3021 KB  
Article
Pancreatic Cancer-Targeting Cascade Nanoamplifier Enables Self-Replenishing H2O2 Generation and Autophagy Disruption in Chemodynamic Therapy
by Jiaqi Yu, Lishuai Feng, Yunpeng Tang, Nianhui Yu, Jianning Lin, Yuan Ji and Hui Li
Pharmaceutics 2025, 17(9), 1201; https://doi.org/10.3390/pharmaceutics17091201 - 16 Sep 2025
Viewed by 947
Abstract
Background/Objectives: Conventional therapeutic strategies exhibit limited efficacy against pancreatic cancer, primarily due to its profoundly hypoxic tumor microenvironment and dense fibrotic stroma. Chemodynamic therapy (CDT) holds promise; however, its application in pancreatic cancer is restricted by insufficient endogenous hydrogen peroxide (H2O [...] Read more.
Background/Objectives: Conventional therapeutic strategies exhibit limited efficacy against pancreatic cancer, primarily due to its profoundly hypoxic tumor microenvironment and dense fibrotic stroma. Chemodynamic therapy (CDT) holds promise; however, its application in pancreatic cancer is restricted by insufficient endogenous hydrogen peroxide (H2O2) levels and the activation of protective autophagy in response to oxidative stress. Methods: To overcome these obstacles, we developed a tumor microenvironment-responsive, pancreatic cancer-targeted CDT nanoamplifier—H-MnO2/GOX&CQ-iRGD—comprising a hollow mesoporous MnO2 shell co-loaded with glucose oxidase (GOX) and chloroquine (CQ), and surface-functionalized with the tumor-penetrating peptide iRGD. GOX catalyzes glucose oxidation to generate H2O2, enhancing Fenton-like reactions. CQ suppresses autophagy induced by oxidative stress, thereby alleviating therapy resistance. The iRGD peptide targets integrin αvβ3, which is overexpressed on pancreatic cancer cells and tumor vasculature, promoting deep tumor penetration and enhanced delivery efficiency. Results: We comprehensively characterized the nanoplatform’s physicochemical properties, tumor microenvironment triggered degradation, controlled drug release, glucose-driven H2O2 generation, and hydroxyl radical production in vitro. Cellular studies assessed nanoparticle uptake, intracellular H2O2 production, autophagy inhibition, and cytotoxicity. In vivo experiments further demonstrated effective tumor targeting and significant therapeutic outcomes in pancreatic cancer models. Conclusions: This nanoplatform addresses major barriers of CDT—namely, insufficient H2O2 levels, autophagy-mediated resistance, and limited intratumoral penetration—offering a promising strategy for pancreatic cancer treatment. Full article
(This article belongs to the Special Issue Nanomedicine and Nanotechnology: Recent Advances and Applications)
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23 pages, 1291 KB  
Article
(Oxidopyridyl)Porphyrins of Different Lipophilicity: Photophysical Properties, ROS Production and Phototoxicity on Melanoma Cells Under CoCl2-Induced Hypoxia
by Martina Mušković, Martin Lončarić, Ivana Ratkaj and Nela Malatesti
Antioxidants 2025, 14(8), 992; https://doi.org/10.3390/antiox14080992 - 13 Aug 2025
Cited by 1 | Viewed by 1011
Abstract
One of the main limitations of photodynamic therapy (PDT) is hypoxia, which is caused by increased tumour proliferation creating a hypoxic tumour microenvironment (TME), as well as oxygen consumption by PDT. Hypoxia-activated prodrugs (HAPs), such as molecules containing aliphatic or aromatic N-oxide [...] Read more.
One of the main limitations of photodynamic therapy (PDT) is hypoxia, which is caused by increased tumour proliferation creating a hypoxic tumour microenvironment (TME), as well as oxygen consumption by PDT. Hypoxia-activated prodrugs (HAPs), such as molecules containing aliphatic or aromatic N-oxide functionalities, are non-toxic prodrugs that are activated in hypoxic regions, where they are reduced into their cytotoxic form. The (oxido)pyridylporphyrins tested in this work were synthesised as potential HAPs from their AB3 pyridylporphyrin precursors, using m-chloroperbenzoic acid (m-CPBA) as an oxidising reagent. Their ground-state and excited-state spectroscopic properties, singlet oxygen (1O2) production by the photodegradation of 1,3-diphenylisobenzofurane (DPBF) and theoretical lipophilicity were determined. In vitro analyses included cellular uptake, localisation and (photo)cytotoxicity under normoxia and CoCl2-induced hypoxia. The CoCl2 hypoxia model was used to reveal their properties, as related to HIF-1 activation and HIF-1α accumulation. (Oxido)pyridylporphyrins showed promising properties, such as the long lifetime of the excited triplet state, a high quantum yield of intersystem crossing, and high production of ROS/1O2. Lower cellular uptake resulted in an overall lower phototoxicity of these N-oxide porphyrins in comparison to their N-methylated analogues, and both porphyrin series were less active on CoCl2-treated cells. (Oxido)pyridylporphyrins showed higher selectivity for pigmented melanoma cells, and the antioxidant activity of melanin pigment seemed to have a lower impact on their PDT activity compared to their N-methylated analogues in both CoCl2-induced hypoxia and normoxia. Their potential HAP activity will be evaluated under conditions of reduced oxygen concentration in our future studies. Full article
(This article belongs to the Section ROS, RNS and RSS)
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18 pages, 2563 KB  
Article
The Potential Anti-Cancer Effects of Polish Ethanolic Extract of Propolis and Quercetin on Glioma Cells Under Hypoxic Conditions
by Małgorzata Kłósek, Anna Kurek-Górecka, Radosław Balwierz, Grażyna Pietsz and Zenon P. Czuba
Molecules 2025, 30(14), 3008; https://doi.org/10.3390/molecules30143008 - 17 Jul 2025
Cited by 2 | Viewed by 1562
Abstract
Tissue hypoxia is commonly observed in head cancers and contributes to both molecular and functional changes in tumour cells. It is known to stimulate erythropoiesis, angiogenesis, and metabolic alterations within tumour cells. Glioblastoma, a type of brain tumour, is characterized by rapid proliferation [...] Read more.
Tissue hypoxia is commonly observed in head cancers and contributes to both molecular and functional changes in tumour cells. It is known to stimulate erythropoiesis, angiogenesis, and metabolic alterations within tumour cells. Glioblastoma, a type of brain tumour, is characterized by rapid proliferation and aggressive growth. Recent studies have indicated that natural products may hold potential as components of cancer therapy. Among these, Polish propolis and its active compound, quercetin, have demonstrated promising anti-cancer properties. The aim of this study was to evaluate the concentrations of selected cytokines—specifically IL-6, IL-9, vascular endothelial growth factor (VEGF), platelet-derived growth factor (PDGF-BB), interferon gamma-induced protein 10 (IP-10), and monocyte chemoattractant protein-1 (MCP-1)—produced by astrocytes of the CCF-STTG1 cell line. The cytotoxic effects of ethanolic extract of propolis (EEP) and quercetin were assessed using the MTT assay. Astrocytes were stimulated with lipopolysaccharide (LPS, 200 ng/mL) and/or IFN-α (100 U/mL), followed by treatment with EEP or quercetin (25–50 µg/mL) under hypoxic conditions for two hours. Cytokine concentrations were measured using the xMAP Luminex Multiplex Immunoassay and the Multiplex Bead-Based Cytokine Kit. Our study demonstrated that Polish propolis and its component quercetin modulate the tumour microenvironment in vitro, primarily by altering the levels of specific cytokines. The HCA analysis revealed that IL-6 and MCP-1 formed a distinct cluster at the highest linkage distance (approximately 100% of Dmax), suggesting that their expression patterns are significantly different from those of the other cytokines and that they are more similar to each other than to the rest. PCA analysis showed that EEP-PL (50 μg/mL) with IFN-α and EEP-PL (50 μg/mL) with LPS exert similar activities on cytokine secretion by astrocytes. Similar effects were demonstrated for EEP-PL 50 μg/mL + LPS + IFN-α, EEP-PL 25 μg/mL + IFN-α and EEP-PL 25 μg/mL + LPS + IFN-α. Our findings suggest that Polish propolis and quercetin may serve as promising natural agents to support the treatment of stage IV malignant astrocytoma. Nonetheless, further research is needed to confirm these results. Full article
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47 pages, 2757 KB  
Review
Influence of Hypoxia on Tumor Heterogeneity, DNA Repair, and Cancer Therapy: From Molecular Insights to Therapeutic Strategies
by Dominika Kunachowicz, Paulina Tomecka, Mikołaj Sędzik, Jarosław Kalinin, Jacek Kuźnicki and Nina Rembiałkowska
Cells 2025, 14(14), 1057; https://doi.org/10.3390/cells14141057 - 10 Jul 2025
Cited by 6 | Viewed by 5136
Abstract
Hypoxia, characterized by a reduction in tissue oxygen levels, is a hallmark of many solid tumors and affects a range of cellular processes, including DNA repair. In low-oxygen conditions, cancer cells often suppress key DNA repair pathways such as homologous recombination (HR), leading [...] Read more.
Hypoxia, characterized by a reduction in tissue oxygen levels, is a hallmark of many solid tumors and affects a range of cellular processes, including DNA repair. In low-oxygen conditions, cancer cells often suppress key DNA repair pathways such as homologous recombination (HR), leading to the accumulation of DNA damage and increased genomic instability. These changes not only drive tumor progression but also contribute to resistance against conventional therapies. Hypoxia significantly reduces the effectiveness of oxygen-dependent treatments, including radiotherapy and many chemotherapeutic agents. To address this limitation, bioreductive drugs have been developed that become selectively activated in hypoxic environments, providing targeted cytotoxic effects within oxygen-deprived tumor regions. Additionally, the rapid growth of tumors often results in disorganized and inefficient vasculature, further impairing the delivery of oxygen and therapeutic agents. This review explores the molecular mechanisms by which hypoxia disrupts DNA repair and contributes to treatment resistance. It also presents emerging therapeutic strategies aimed at targeting the hypoxic tumor microenvironment to improve treatment efficacy and patient outcomes. Full article
(This article belongs to the Section Cell Microenvironment)
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23 pages, 6014 KB  
Article
Evofosfamide Enhances Sensitivity of Breast Cancer Cells to Apoptosis and Natural-Killer-Cell-Mediated Cytotoxicity Under Hypoxic Conditions
by Shubhankar Das, Goutham Hassan Venkatesh, Walid Shaaban Moustafa Elsayed, Raefa Abou Khouzam, Ayda Shah Mahmood, Husam Hussein Nawafleh, Nagwa Ahmed Zeinelabdin, Rania Faouzi Zaarour and Salem Chouaib
Cancers 2025, 17(12), 1988; https://doi.org/10.3390/cancers17121988 - 14 Jun 2025
Cited by 1 | Viewed by 1559
Abstract
Background/objectives: Hypoxia in the tumor microenvironment is linked to aggressiveness, epithelial–mesenchymal transition, metastasis, and therapy resistance. Targeting hypoxia to enhance antitumor immunity is crucial for overcoming therapeutic resistance. Here, we investigated the ability of Evofosfamide, a prodrug that gets activated under hypoxic conditions, [...] Read more.
Background/objectives: Hypoxia in the tumor microenvironment is linked to aggressiveness, epithelial–mesenchymal transition, metastasis, and therapy resistance. Targeting hypoxia to enhance antitumor immunity is crucial for overcoming therapeutic resistance. Here, we investigated the ability of Evofosfamide, a prodrug that gets activated under hypoxic conditions, to sensitize breast cancer cells to cell death. Evofosfamide is converted into bromo-isophosphoramide mustard, a potent DNA cross-linking agent that is expected to enhance the killing of cancer cells under hypoxic conditions, where these cells typically exhibit resistance. Methods: Representative breast cancer cell lines, MCF-7 and MDA-MB-231, were treated with Evofosfamide under normoxia and hypoxia. Changes in cell viability and the mechanism of cell death were measured using neutral red dye uptake, Annexin-FITC/propidium iodide staining, and Western blot analysis of markers—PARP1 and caspase 3/7. We tested Evofosfamide’s ability to counteract hypoxic suppression of type I Interferon signaling genes using quantitative PCR (qPCR), as well as its capacity to trigger natural killer (NK)-cell-mediated cytotoxicity. Results: Evofosfamide enhanced cell killing in both MCF-7 and MDA-MB-231 cells under hypoxic conditions compared to normoxic conditions. Cell killing was accompanied by increased cellular reactive oxygen species (ROS), diminished mitochondrial membrane potential, and induction of apoptosis, as demonstrated by the fragmentation or laddering of genomic DNA, the activation of caspase 3/7, and the cleavage of PARP. qPCR analysis revealed that Evofosfamide was capable of restoring type I interferon signaling in hypoxic breast cancer cells, leading to the subsequent cytolytic activity of NK cells against the tumor cells. Conclusions: Thus, conditioning the breast cancer cells with Evofosfamide resulted in enhanced cell killing under hypoxia, further underscoring its potential as a sensitizer to target hypoxia-driven tumors. Full article
(This article belongs to the Section Tumor Microenvironment)
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16 pages, 4183 KB  
Article
Glyceraldehyde 3-Phosphate Dehydrogenase and Galectin from Dirofilaria immitis Excretory/Secretory Antigens Activate Proangiogenic Pathway in In Vitro Vascular Endothelial Cell Model
by Manuel Collado-Cuadrado, Alfonso Balmori-de la Puente, Iván Rodríguez-Escolar, Elena Infante González-Mohino, Claudia Alarcón-Torrecillas, Miguel Pericacho and Rodrigo Morchón
Animals 2025, 15(7), 964; https://doi.org/10.3390/ani15070964 - 27 Mar 2025
Viewed by 913
Abstract
Heartworm disease is caused by Dirofilaria immitis, which mainly affects canids and felids. Adult D. immitis worms are located between the heart’s right ventricle and the pulmonary artery. These parasites produce an inflammatory and hypoxic process in the vascular endothelium. It has [...] Read more.
Heartworm disease is caused by Dirofilaria immitis, which mainly affects canids and felids. Adult D. immitis worms are located between the heart’s right ventricle and the pulmonary artery. These parasites produce an inflammatory and hypoxic process in the vascular endothelium. It has been demonstrated that D. immitis excretory/secretory antigens are able to stimulate the angiogenic process as a survival mechanism of D. immitis in the vascular endothelium, stimulating the proangiogenic pathway and related cellular processes. Our goal was to study the role of glyceraldehyde 3-phosphate dehydrogenase (GAPDH) and galectin (GAL) (proteins of D. immitis excretory/secretory antigens) plus vascular endothelial growth factor isoform A (VEGF-A) in the angiogenic process and their relationship with three cellular processes (cell proliferation, cell migration, and pseudocapillary formation) in an in vitro model of vascular endothelial cells. Cell viability and cytotoxicity were analyzed by live cell analysis and a commercial kit, respectively. VEGF-A, sVEGFR-2, VEGFR-1/sFlt, soluble endoglin, and membrane endoglin were analyzed by commercial ELISA kits. Cell proliferation, cell migration, and pseudocapillary formation were analyzed by MTT-based assay, the wound healing technique, and counting cell connections and cell clusters, respectively. rDiGAPDH+VEGF-A and rDiGAL+VEGF-A significantly increased the expression of sVEGFR-2, mEndoglin, and VEGF-A compared to cultures treated with only the proteins (rDiGAPDH and rDiGAL), VEGF-A, or unstimulated cultures. In addition, they also produced a significant increase in cell proliferation, cell migration, and pseudocapillary formation. Therefore, these proteins together with VEGF-A can activate the proangiogenic pathway and could be related to D. immitis survival in the circulatory system. Full article
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17 pages, 9363 KB  
Article
5-Aminolaevulinic Acid-Mediated Photodynamic Therapy Combined with Tirapazamine Enhances Efficacy in Ovarian Cancer
by Qian Wang, Yuping Suo and Xiaojuan Tian
Biomedicines 2025, 13(3), 724; https://doi.org/10.3390/biomedicines13030724 - 16 Mar 2025
Cited by 1 | Viewed by 1148
Abstract
Objectives: Ovarian cancer is a common gynaecological malignancy. Photodynamic therapy (PDT) mediated by 5-aminolaevulinic acid (5-ALA-PDT) is widely used in clinical practice. However, hypoxia may impact the efficacy of this treatment. In the present study, we combined the bioreductively active drug tirapazamine [...] Read more.
Objectives: Ovarian cancer is a common gynaecological malignancy. Photodynamic therapy (PDT) mediated by 5-aminolaevulinic acid (5-ALA-PDT) is widely used in clinical practice. However, hypoxia may impact the efficacy of this treatment. In the present study, we combined the bioreductively active drug tirapazamine (TPZ) with PDT to explore its potential in enhancing ovarian cancer cell death. Methods: A cell counting kit-8 assay was used to determine cytotoxicity under different intervention conditions. The distribution of protoporphyrin IX, a metabolite of 5-ALA, was observed using in vivo fluorescence imaging. The effect of the combined treatment was assessed by measuring changes in tumour size following the corresponding interventions and by haematoxylin and eosin staining of tumour tissues. Immunohistochemical staining was used to detect the expression levels of relevant proteins. Results: TPZ exhibited no cytotoxicity under normoxic conditions but was activated under hypoxic conditions, inducing cytotoxic effects that were enhanced when combined with PDT. Over time, protoporphyrin IX achieved systemic distribution, and high drug concentrations were maintained within the tumour. The combination therapy suppressed tumour growth, and pathological staining showed that necrotic tumour areas were significantly enlarged after treatment. The enhanced therapeutic effect may be attributable to the inhibition of the hypoxia-inducible factor-1α/vascular endothelial growth factor axis and PI3K/Akt/mTOR pathway. Conclusions: 5-ALA-PDT combined with TPZ can overcome both the hypoxic state of ovarian cancer tissues and the increased hypoxia induced by PDT, thereby inhibiting tumour growth. Full article
(This article belongs to the Section Cancer Biology and Oncology)
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14 pages, 4863 KB  
Article
Hong-Bai-Lan-Shen Extract Alleviates the CoCl2-Induced Apoptosis in H9C2 Cells by Regulating the AMPK Pathway
by Jinxue Ding, Jinwu Meng, Wenjia Wang, Bolin Gu, Mengxin Hu and Jiaguo Liu
Vet. Sci. 2025, 12(3), 267; https://doi.org/10.3390/vetsci12030267 - 13 Mar 2025
Viewed by 1162
Abstract
This study aims to explore the protective effects of Hong-bai-lan-shen (HBLS) extract, a traditional Chinese medicine compound, on myocardial injury based on metabolomics. H9C2 cells were cultured with HBLS extract for 12 h, and then the cells were cultured in a CoCl2 [...] Read more.
This study aims to explore the protective effects of Hong-bai-lan-shen (HBLS) extract, a traditional Chinese medicine compound, on myocardial injury based on metabolomics. H9C2 cells were cultured with HBLS extract for 12 h, and then the cells were cultured in a CoCl2-containing medium, a model simulating the ischemic-hypoxic damage in myocardial cells, for an additional 12 h. The cell viability, cytotoxicity, intracellular metabolite and reactive oxygen species (ROS), mitochondrial membrane potential, apoptosis, and adenosine monophosphate-activated protein kinase (AMPK) signal pathway were determined. The results showed that HBLS extract significantly increased cell viability, stabilized cell morphology, reduced lactate dehydrogenase (LDH) release and ROS production, blocked cysteine-aspartic acid protease 3 (caspase-3) and bcl-2-associated X protein (Bax) expression and decreased apoptotic cell numbers. Meanwhile, HBLS increased membrane potential and the expression of B-cell lymphoma-2 (Bcl-2). Additionally, HBLS extract upregulated the expression of AMPK, PI3K, and protein kinase B (AKT) (p < 0.05, p < 0.01). These findings suggest that HBLS extract has a protective effect on myocardial cells by regulating the AMPK signal pathway and may be a promising therapeutic candidate for ischemic heart disease. Full article
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21 pages, 9529 KB  
Article
The Effect of Ethanolic Extract of Brazilian Green Propolis and Artepillin C on Cytokine Secretion by Stage IV Glioma Cells Under Hypoxic and Normoxic Conditions
by Małgorzata Kłósek, Anna Kurek-Górecka, Radosław Balwierz, Grażyna Pietsz and Zenon P. Czuba
Pharmaceuticals 2025, 18(3), 389; https://doi.org/10.3390/ph18030389 - 9 Mar 2025
Cited by 4 | Viewed by 4563
Abstract
Background: The majority of gliomas are astrocytic in nature. Gliomas have the lowest survival rate among all tumors of the central nervous system (CNS), characterized by high aggressiveness and poor response to treatment. The tumor microenvironment is a source of cytokines such as [...] Read more.
Background: The majority of gliomas are astrocytic in nature. Gliomas have the lowest survival rate among all tumors of the central nervous system (CNS), characterized by high aggressiveness and poor response to treatment. The tumor microenvironment is a source of cytokines such as IL-6, IFN-γ, VEGF, and PDGF-BB, secreted mainly by tumor and immune cells. These cytokines play a significant role in angiogenesis, invasion, and metastasis formation. In vitro and in vivo studies have shown that Brazilian green propolis, derived from Baccharis dracunculifolia DC and rich in artepillin C, exhibits anti-inflammatory, antimicrobial, chemopreventive, and anticancer activities. Additionally, it can penetrate the blood–brain barrier, demonstrating neuroprotective effects. The aim of the present study was to determine the concentration of selected cytokines produced by astrocytes of the CCF-STTG1 cell line, isolated from the brain of a patient with stage IV glioma (astrocytoma). Methods: The cytotoxicity of the EEP-B was evaluated using the MTT assay. Astrocytes were stimulated with LPS at a final concentration of 200 ng/mL and/or IFN-α at 100 U/mL, followed by incubation with EEP-B (25–50 µg/mL) and artepillin C (25–50 µg/mL) under 2-h hypoxia and normoxia conditions. Cytokine concentrations were measured using the xMAP Luminex Multiplex Immunoassay and the Multiplex Bead-Based Cytokine kit. Results: The absence of cytotoxic effects of EEP-B and artepillin C on human astrocytes of the CCF-STTG1 lineage was demonstrated. Stimulation with LPS, IFN-α, and their combination (LPS + IFN-α) significantly increased the secretion of the tested cytokines compared to the control cell line. The most pronounced and statistically significant reduction in cytokine levels, particularly IL-6 and VEGF, was observed following EEP-B treatment at both tested concentrations under both hypoxic and normoxic conditions. Conclusions: Brazilian green propolis may serve as a potential immunomodulator in combination therapies for gliomas of varying malignancy grades. Full article
(This article belongs to the Special Issue Antioxidant and Anti-Inflammatory Effects of Natural Product Extracts)
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Article
Naringin Suppresses CoCl2-Induced Ferroptosis in ARPE-19 Cells
by Yuchang Yang, Manting Liu, Xiaoxv Dong, Jie Bai, Wenjuan Shi, Qian Zhu, Juan Liu, Ziheng Wang, Lisa Yi, Xingbin Yin, Jian Ni and Changhai Qu
Antioxidants 2025, 14(2), 236; https://doi.org/10.3390/antiox14020236 - 18 Feb 2025
Cited by 4 | Viewed by 1817
Abstract
Hypoxic damage to retinal pigment epithelial (RPE) cells and subsequent neovascularization are key factors in the pathogenesis of branch retinal vein occlusion (BRVO). Naringin (NG), a naturally occurring flavanone glycoside, has demonstrated significant antioxidant and anti-neovascular activities. However, the regulatory effects and mechanisms [...] Read more.
Hypoxic damage to retinal pigment epithelial (RPE) cells and subsequent neovascularization are key factors in the pathogenesis of branch retinal vein occlusion (BRVO). Naringin (NG), a naturally occurring flavanone glycoside, has demonstrated significant antioxidant and anti-neovascular activities. However, the regulatory effects and mechanisms of NG on ferroptosis in BRVO are yet to be explored. Our study aimed to investigate the protective effects of NG on RPE cells under hypoxic stress and to elucidate the underlying molecular mechanisms. Our findings revealed that NG significantly reduced cytotoxicity induced by cobaltous chloride (CoCl2) and also inhibited vascular proliferation in the retina, thereby attenuating choroidal neovascularization. NG pretreatment largely countered the overproduction of reactive oxygen species (ROS) and malondialdehyde (MDA) triggered by hypoxic damage, while also restoring levels of the antioxidants glutathione (GSH) and superoxide dismutase (SOD). Furthermore, NG pretreatment significantly activated the expression of hypoxia-inducible factor-1 alpha (HIF-1α) and its downstream heme oxygenase-1 (HO-1) and NADPH dehydrogenase (NQO1). In conclusion, NG not only inhibits neovascularization but also alleviates inflammation in RPE cells by modulating the HO-1/GPX4 pathway to inhibit ferroptosis. These findings highlight the potential of NG as a promising therapeutic agent for the treatment of BRVO. Full article
(This article belongs to the Section Natural and Synthetic Antioxidants)
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