Search Results (361)

Bone is the most frequent site of distant metastasis in advanced prostate cancer (PCa), contributing substantially to patient morbidity and mortality. Hypoxia, a defining feature of the solid tumour microenvironment, plays a pivotal role in driving bone-tropic progression by promoting epithelial-to-mesenchymal transition (EMT), cancer stemness, extracellular matrix (ECM) remodelling, and activation of key signalling pathways such as Wingless/Integrated (Wnt) Wnt/β-catenin and PI3K/Akt. Hypoxia also enhances the secretion of extracellular vesicles (EVs), enriched with pro-metastatic cargos, and upregulates bone-homing molecules including CXCR4, integrins, and PIM kinases, fostering pre-metastatic niche formation and skeletal colonisation. In this review, we analysed current evidence on how hypoxia orchestrates PCa dissemination to bone, focusing on the molecular crosstalk between HIF signalling, Wnt activation, EV-mediated communication, and cellular plasticity. We further explore therapeutic strategies targeting hypoxia-related pathways, such as HIF inhibitors, hypoxia-activated prodrugs, and Wnt antagonists, with an emphasis on overcoming therapy resistance in castration-resistant PCa (CRPC). By examining the mechanistic underpinnings of hypoxia-driven bone metastasis, we highlight promising translational avenues for improving patient outcomes in advanced PCa. Full article

Cutaneous malignant melanoma is an extraordinarily aggressive and heterogeneous cancer that contains a small subpopulation of tumor stem cells (CSCs) responsible for tumor initiation, metastasis, and recurrence. Identification and characterization of CSCs in melanoma is challenging due to tumor heterogeneity and the lack of specific markers (CD271, ABCB5, ALDH, Nanog) and the ability of cells to dynamically change their phenotype. Phenotype-maintaining signaling pathways (Wnt/β-catenin, Notch, Hedgehog, HIF-1) promote self-renewal, treatment resistance, and epithelial–mesenchymal transitions. Tumor plasticity reflects the ability of differentiated cells to acquire stem-like traits and phenotypic flexibility under stress conditions. The interaction of CSCs with the tumor microenvironment accelerates disease progression: they induce the formation of cancer-associated fibroblasts (CAFs) and neo-angiogenesis, extracellular matrix remodeling, and recruitment of immunosuppressive cells, facilitating immune evasion. Emerging therapeutic strategies include immunotherapy (immune checkpoint inhibitors), epigenetic inhibitors, and nanotechnologies (targeted nanoparticles) for delivery of chemotherapeutic agents. Understanding the role of CSCs and tumor plasticity paves the way for more effective innovative therapies against melanoma. Full article

Belzutifan is a hypoxia-inducible factor-2α (HIF-2α) inhibitor that received FDA approval in 2021 for treating cancers resulting from von Hippel-Lindau (VHL) disease, including clear cell renal cell carcinoma (ccRCC), followed by approval in 2023 for sporadic ccRCC that has progressed through multiple lines of therapy. HIF-2α is a promising drug target, as VHL is commonly inactivated in ccRCC, which results in HIF-2α-mediated signaling that is considered central to tumorigenesis. Belzutifan has demonstrated efficacy in clinical trials in the first-line and subsequent line settings, and in combination with tyrosine kinase inhibitors. Despite being overall well tolerated, belzutifan has a distinct safety profile because of its unique mechanism of action. Anemia was the most common adverse event observed in clinical trials and is considered an on-target effect. Hypoxia is also frequently observed and commonly results in dose reductions, treatment discontinuation, and supplemental oxygen use. This review summarizes the rates of hypoxia seen in clinical trials of belzutifan in ccRCC. As the cause of hypoxia is not well understood, this review also discusses possible mechanisms of hypoxia based on preclinical studies of the HIF pathway and HIF-2α inhibitors. Finally, this review proposes monitoring and management recommendations for clinicians prescribing belzutifan to ccRCC patients. Full article

Chronic kidney disease (CKD)-associated anemia is a global health concern and is linked to vascular and ocular complications. Hypoxia-inducible factor (HIF) stabilizers, or HIF prolyl hydroxylase inhibitors (PHIs), are promising candidates for the treatment of CKD-associated anemia. Since hypoxia and angiogenesis are involved in eye diseases, this study examined the effects of HIF-PHIs on metabolism and gene expression in retinal pigment epithelium (RPE) cells. Results revealed that PHIs differentially induced angiogenic (VEGFA, ANG) and glycolytic (PDK1, GLUT1) gene expression, with Roxadustat causing the strongest transcriptional changes. However, Roxadustat-induced angiogenic signals did not promote endothelial tube formation. Moreover, it did not induce oxidative stress, inflammation, or significant antioxidant gene responses in ARPE-19 cells. Roxadustat also reduced the inflammatory cytokine response to tumor necrosis factor-α, including IL-6, IL-8, and MCP-1, and did not exacerbate VEGF expression under high-glucose conditions. Overall, Roxadustat triggered complex gene expression changes without promoting inflammation or oxidative stress in RPE cells. Despite these findings, ophthalmologic monitoring is advised during PHI treatment in CKD patients receiving HIF-PHIs. Full article

Hepatocellular carcinoma (HCC) remains a major clinical challenge due to its high recurrence rate and limited response to monotherapies, such as sorafenib—the standard first-line therapy for advanced HCC. This is partly attributed to its cellular heterogeneity. Increasing evidence implies SRC family kinase (SFK) activation in HCC progression, highlighting the potential of SRC-targeted therapies. In this study, we observed that SRC and YES1 were significantly upregulated in clinical HCC specimens compared to its adjacent non-tumoral tissues (p < 0.001), suggesting relevance as therapeutic targets. High SRC expression was noticed in patients with poor prognosis, as confirmed in TCGA cohort. To evaluate the efficacy of dual targeting, we assessed the combination between SRC inhibitors, saracatinib and dasatinib, with sorafenib in six hepatic cell models, representing both S1 and S2 subtypes. Cytotoxicity assays demonstrated reduced cell viability with the combination therapies compared to either monotherapy, irrespective of the HCC subtype. Wound healing and Transwell migration assays revealed inhibition of cell migration and invasion following combination treatment, underscoring its potential to suppress metastatic behavior. RT-qPCR analysis further confirmed downregulation of the expression of MMP2 and MMP9, genes associated with HCC cell invasion. Additionally, combined therapies decreased VEGFA and HIF1A expression compared to sorafenib alone, suggesting a potential to counteract the adaptive resistance mechanisms of cells to sorafenib. In summary, the combination of SFK inhibitors with sorafenib significantly enhances anti-tumor activity, offering a promising strategy to address HCC cellular heterogeneity and improve treatment efficacy. Full article

Transcription factors (TFs) are proteins that control gene expression by binding to specific DNA sequences and are essential for cell development, differentiation, and homeostasis. Dysregulation of TFs is implicated in numerous diseases, including cancer, autoimmune disorders, and neurodegeneration. While TFs were traditionally considered “undruggable” due to their lack of well-defined binding pockets, recent advances have made it possible to modulate their activity using diverse pharmacological strategies. Major TF families include NF-κB, p53, STATs, HIF-1α, AP-1, Nrf2, and nuclear hormone receptors, which take part in the regulation of inflammation, tumor suppression, cytokine signaling, hypoxia and stress response, oxidative stress, and hormonal response, respectively. TFs can perform multiple functions, participating in the regulation of opposing processes depending on the context. NF-κB, for instance, plays dual roles in immunity and cancer, and is targeted by proteasome and IKKβ inhibitors. p53, often mutated in cancer, is reactivated using MDM2 antagonist Nutlin-3, refunctionalizing compound APR-246, or stapled peptides. HIF-1α, which regulates hypoxic responses and angiogenesis, is inhibited by agents like acriflavine or stabilized in anemia therapies by HIF-PHD inhibitor roxadustat. STATs, especially STAT3 and STAT5, are oncogenic and targeted via JAK inhibitors or novel PROTAC degraders, for instance SD-36. AP-1, implicated in cancer and arthritis, can be inhibited by T-5224 or kinase inhibitors JNK and p38 MAPK. Nrf2, a key antioxidant regulator, can be activated by agents like DMF or inhibited in chemoresistant tumors. Pharmacological strategies include direct inhibitors, activators, PROTACs, molecular glues, and epigenetic modulators. Challenges remain, including the structural inaccessibility of TFs, functional redundancy, off-target effects, and delivery barriers. Despite these challenges, transcription factor modulation is emerging as a viable and promising therapeutic approach, with ongoing research focusing on specificity, safety, and efficient delivery methods to realize its full clinical potential. Full article

Hypoxia-inducible factor prolyl hydroxylase (HIF-PH) inhibitors continually stabilize hypoxia-inducible factor-1α (HIF-1α). These inhibitors are effective in the clinical treatment of renal anemia. However, the effects of continued HIF-1α stabilization on skeletal muscle differentiation remain unclear. This study aimed to investigate the effects of continued HIF-1α stabilization on skeletal muscle differentiation using a HIF-PH inhibitor in both in vitro and in vivo models. We cultured mouse C2C12 myoblasts to differentiate into myotubes with or without FG-4592, a HIF-PH inhibitor. Additionally, we treated nine-week-old male C57BL/6 mice with either FG-4592 or vehicle via intraperitoneal injections three times a week for four weeks. In vitro, FG-4592 treatment stabilized HIF-1α continually. Morphological analysis revealed that 72 h FG-4592 treatment suppressed differentiation of C2C12 myoblasts into myotubes. This treatment decreased the gene and protein expression of MyoD and myogenin, reduced the protein expression of myosin heavy chain (MHC), and increased the gene and protein expression of myostatin. HIF-1α knockdown mitigated the decrease in MHC protein expression induced by FG-4592. In vivo, FG-4592 treatment increased HIF-1α protein expression and decreased MyoD, myogenin, and MHC protein expression in gastrocnemius muscle. These findings suggest that pharmacological HIF-PH inhibition suppresses myoblast differentiation through continued HIF-1α stabilization. Full article

Gallbladder cancer (GBC) is a highly aggressive malignancy with a propensity for lymph node metastasis (LNM), which significantly worsens prognosis. This review explores the molecular mechanisms underlying LNM in GBC, focusing on the roles of vascular endothelial growth factors (VEGFs), chemokines, cancer-associated fibroblasts (CAFs), tumor-associated macrophages (TAMs), hypoxia-inducible factors (HIFs), and non-coding RNAs (ncRNAs) in shaping the tumor microenvironment (TME). Unique features of GBC, such as its bile-rich microenvironment and hypoxia-driven lymphangiogenesis, are highlighted. We discuss how these factors promote lymphangiogenesis, immune evasion, and extracellular matrix (ECM) remodeling, collectively facilitating LNM. Potential therapeutic targets, including VEGF-C/D pathways, matrix metalloproteinase (MMP) inhibitors, and immune-modulating therapies, are also reviewed. Future research integrating single-cell omics and patient-derived organoid models is essential for advancing precision medicine in GBC. Full article

Glioblastoma (GBM) is the most common primary brain tumor in adults, with a median survival of 15–18 months. GBM cells, like all tumors, exhibit a metabolic shift known as the Warburg effect, favoring glycolysis even under normoxic conditions. GLUT1 is a primary glucose transporter in GBM cells and has been found to be overexpressed in these cells. The acidic microenvironment created by glycolysis facilitates immune evasion, therapy resistance, and tumor growth. Overexpression of GLUT1 is driven by hypoxia-inducible factor-1α (HIF-1α), c-Myc, and other pathways which have been correlated with tumor aggressiveness as well as poor prognosis Recent studies have highlighted the therapeutic potential of targeting GLUT1 in GBM. Preclinical research shows that GLUT1 inhibitors, such as WZB117 and BAY-876, effectively impair tumor metabolism, reduce cell viability, and improve survival in vitro and in animal models. GLUT1 expression also serves as a prognostic marker, with elevated levels linked to poor outcomes. This review highlights the importance of GLUT1 in GBM biology as a potential therapeutic target and biomarker. Full article

Endometriosis is a chronic gynecological disorder characterized by the presence of endometrial-like tissue outside the uterus, leading to inflammation, pain, and infertility. Emerging evidence indicates that endometriotic lesions exhibit cancer-like properties, including metabolic reprogramming marked by increased glucose uptake, enhanced Warburg’s effect, and altered mitochondrial function. These metabolic adaptations support cell survival under hypoxic conditions and contribute to immune evasion and sustained proliferation. This review summarizes current findings on the molecular mechanisms driving metabolic reprogramming in endometriosis, including the roles of mitochondrial dysfunction, hypoxia-inducible factor (HIF) signaling, the PI3K/AKT/mTOR pathway, inflammatory cytokines, and genetic and epigenetic regulators. In addition, we discuss therapeutic strategies targeting glycolytic pathways using both synthetic inhibitors and natural compounds, which represent promising non-hormonal options. Finally, we highlight the need for further preclinical and clinical studies to validate metabolic interventions and improve outcomes for patients with endometriosis. Full article

Background: Von Hippel-Lindau (VHL) disease, a hereditary cancer syndrome, is characterized by mutations in the VHL gene, which result in the stabilization of hypoxia-inducible factors (HIF)-1α and -2α, ultimately leading to the development of highly vascularized tumors, such as hemangioblastomas of the central nervous system (CNS-HBs). The standard treatment for these brain tumors is neurosurgical resection. However, multiple surgeries are often necessary due to tumor recurrence, which increases the risk of neurological sequelae. Thus, elucidation of the proliferative behavior of hemangioblastomas (with the aim of identifying biomarkers associated with tumor progression) and the development of pharmacological therapies could reduce the need for repeated surgical interventions and provide alternative treatment options for unresectable CNS-HBs. Belzutifan (Welireg™), a selective HIF-2α inhibitor and the only FDA-approved non-surgical option, has shown limited efficacy in CNS-HBs, highlighting the need for alternative therapeutic strategies. Results: In this study, primary cell cultures were successfully established from CNS-HB tissue samples of VHL patients, achieving a 75% success rate. These cultures were predominantly composed of stromal cells and pericytes. The proliferative patterns of patient-derived HB cell cultures significantly correlated with tumor burden and recurrence in VHL patients. Furthermore, flow cytometry, reverse transcription-PCR, and Western blot analyses revealed marked overexpression of both HIF-1α and HIF-2α isoforms in primary HB cells. In addition, evaluation of the therapeutic potential of acriflavine, a dual HIF-1α/HIF-2α inhibitor, demonstrated reduced HB cells viability, induced G2/M cell cycle arrest, and predominantly triggered necrotic cell death in patient-derived HB cultures. Conclusions: These results suggest that the in vitro proliferative dynamics of HB cell cultures may reflect clinical characteristics associated with CNS-HB progression, potentially serving as indicators to predict tumor development in patients with VHL. Furthermore, our findings support the simultaneous targeting of both HIF-1α and HIF-2α isoforms as a promising non-invasive therapeutic strategy. Full article

Renal cell carcinoma (RCC) accounts for about 3% of all human tumors. Alterations of oxygen, lipids, iron, and energy metabolism are involved in carcinogenesis, development, and expansion. Thirty percent of patients affected by clear cell renal cell carcinoma (ccRCC) will develop relapses or distance metastases (mRCC), dramatically reducing their life expectancy. Current first-line therapies for mRCC patients are based on treatment with immune checkpoint inhibitors (ICIs) alone and in combination with each other or with tyrosine kinase inhibitors (TKIs). However, only 20% of patients show a mild response because of innate or acquired drug resistance during long-term treatment; therefore, resistant patients need alternative first-line or second-line therapies. Pharmacological resistance represents a big problem that counteracts the efficacy of treatment by reducing overall survival (OS) in mRCC patients. Investigating the molecular mechanisms underlying drug resistance is crucial to overcoming drug insensitivity and enhancing therapeutic outcomes. In this review, we emphasize the latest and most significant studies on the molecular mechanisms that drive drug resistance in ccRCC carcinoma. Particular attention is given to the key signaling pathways involved in resistance, including those mediated by HIF, p53, Akt-mTOR, MEK–ERK cascades, Wnt signaling, autophagy, membrane transporters, ferroptosis, and non-coding RNAs. Understanding these resistance mechanisms is essential for developing new therapeutic strategies aimed to enhancing overall OS and improving the quality of life for mRCC patients. This review also discusses recent clinical trial findings on the use of specific inhibitors able to circumvent drug resistance. The data presented here could be valuable for clinicians in understanding the mechanisms of drug resistance, ultimately aiding in the management of ccRCC patients. Full article

Hepatocellular carcinoma (HCC) is a commonly diagnosed malignancy, with the treatment for transplant-ineligible localized disease traditionally relying on locoregional therapies, such as surgical resection, transarterial chemoembolization (TACE), and transarterial radioembolization (TARE). Systemic therapy has historically been reserved for advanced, unresectable HCC. However, lenvatinib, an oral multikinase inhibitor, has recently gained traction as part of a multimodal approach for localized HCC in combination with locoregional treatments. An upfront TACE or TARE can induce tumor hypoxia, leading to the upregulation of hypoxia-inducible factor-1 alpha (HIF-1α) and vascular endothelial growth factor (VEGF), which promotes tumor angiogenesis and progression. The rationale for combining lenvatinib with a locoregional therapy is to enhance tumor shrinkage while preserving liver function before a definitive intervention. Clinical trials, such as TACTICS and LAUNCH, have demonstrated improved outcomes with this approach. Additionally, retrospective studies, including those incorporating immune checkpoint inhibitors, have reported further benefits. This review explores the combination of lenvatinib with various locoregional modalities, including TARE, microwave ablation (MWA), and radiofrequency ablation (RFA), highlighting their indications and clinical outcomes. Furthermore, we discuss the ongoing and upcoming clinical trials investigating the integration of systemic agents with locoregional therapies for intermediate-stage HCC, including EMERALD-1, EMERALD-3, LEAP-012, and CheckMate 74W. Full article

β-adrenoceptors (BARs) are involved in vascular endothelial growth factor (VEGF) production during retinal neovascularization. Here, using human retinal endothelial and Müller cells (hRECs and MIO-M1, respectively), we evaluated the effects exerted by hypoxia on BARs, hypoxia-inducible factor-1α subunit (HIF-1α) and VEGF, as well as the involvement of BAR3 and nitric oxide synthase (NOS) enzymes in hypoxia-induced VEGF production. We altered oxygen availability through a hypoxic incubator. BARs, HIF-1 α and VEGF levels were evaluated. Cells were treated with the BAR3 antagonist SR59230A, different NOS inhibitors or the NO donor SNAP. The influence of the BAR3/NOS axis on hypoxic VEGF production was assessed. Hypoxia upregulated BAR3, HIF-1α and VEGF in hRECs and MIO-M1 cells. SR59230A counteracted hypoxia-dependent VEGF increase in both cell lines, exerting no effect on HIF-1α upregulation. Treatments with NOS inhibitors prevented the hypoxia-dependent VEGF increase, while SNAP abrogated the effect of SR59230A in reducing hypoxia-induced VEGF upregulation. The present results corroborate the hypothesis that in the hypoxic retina, BAR3 influence on VEGF production is mediated by NO and suggest that, at least in endothelial and Müller cells, BAR3 activity is necessary to allow the HIF-1-mediated VEGF upregulation. Full article

Retinal ischemic disorders present significant threats to vision, characterized by inadequate blood supply oxygen–glucose deprivation (OGD), oxidative stress, and cellular injury, often resulting in irreversible injury. Catalpol, an iridoid glycoside derived from Rehmannia glutinosa, has demonstrated antioxidative and neuroprotective effects. This study aimed at investigating the protective effects and mechanisms of catalpol against oxidative stress or OGD in vitro and retinal ischemia in vivo, focusing on the modulation of key biomarkers of retinal ischemia, including HIF-1α, vascular endothelial growth factor (VEGF), angiopoietin-2, MCP-1, and the Wnt/β-catenin pathway. Cellular viability was assessed using retinal ganglion cell-5 (RGC-5) cells cultured in DMEM; a 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay was performed. H₂O₂ (1 mM)/OGD was utilized. Vehicle or different catalpol concentrations were administered 15 min before the ischemic-like insults. The Wistar rat eyes’ intraocular pressure was increased to 120 mmHg for 60 min to induce retinal ischemia. Intravitreous injections of catalpol (0.5 or 0.25 mM), Wnt inhibitor DKK1 (1 μg/4 μL), anti-VEGF Lucentis (40 μg/4 μL), or anti-VEGF Eylea (160 μg/4 μL) were administered to the rats’ eyes 15 min before or after retinal ischemia. Electroretinogram (ERG), fluorogold retrograde labeling RGC, Western blotting, ELISA, RT-PCR, and TUNEL were utilized. In vitro, both H₂O₂ and OGD models significantly (p < 0.001/p < 0.001; H₂O₂ and OGD) induced oxidative stress/ischemic-like insults, decreasing RGC-5 cell viability (from 100% to 55.14 ± 2.19%/60.84 ± 4.57%). These injuries were insignificantly (53.85 ± 1.28% at 0.25 mM)/(63.46 ± 3.30% at 0.25 mM) and significantly (p = 0.003/p = 0.012; 64.15 ± 2.41%/77.63 ± 8.59% at 0.5 mM) altered by the pre-administration of catalpol, indicating a possible antioxidative and anti-ischemic effect of 0.5 mM catalpol. In vivo, catalpol had less effect at 0.25 mM for ERG amplitude ratio (median [Q1, Q3] 14.75% [12.64%, 20.48%]) and RGC viability (mean ± SE 63.74 ± 5.13%), whereas (p < 0.05 and p < 0.05) at 0.5 mM ERG’s ratio (35.43% [24.35%, 43.08%]) and RGC’s density (74.34 ± 5.10%) blunted the ischemia-associated significant (p < 0.05 and p < 0.01) reduction in ERG b-wave amplitude (6.89% [4.24%, 10.40%]) and RGC cell viability (45.64 ± 3.02%). Catalpol 0.5 mM also significantly protected against retinal ischemia supported by the increased amplitude ratio of ERG a-wave and oscillatory potential, along with recovering a delayed a-/b-wave response time ratio. When contrasted with DKK1 or Lucentis, catalpol exhibited similar protective effects against retinal ischemia via significantly (p < 0.05) blunting the ischemia-induced overexpression of β-catenin, VEGF, or angiopoietin-2. Moreover, ischemia-associated significant increases in apoptotic cells in the inner retina, inflammatory biomarker MCP-1, and ischemic indicator HIF-1α were significantly nullified by catalpol. Catalpol demonstrated antiapoptotic, anti-inflammatory, anti-ischemic (in vivo retinal ischemia or in vitro OGD), and antioxidative (in vitro) properties, counteracting retinal ischemia via suppressing upstream Wnt/β-catenin and inhibiting downstream HIF-1α, VEGF, and angiopoietin-2, together with its decreasing TUNEL apoptotic cell number and inflammatory MCP-1 concentration. Full article