Using single-cell transcriptomics, lysyl oxidase (LOX) is identified as a driver of ccRCC progression, selectively enriched in a hypoxia/epithelial-mesenchymal transition (EMT) gene program associated with poor outcome.
Abstract
Clear cell renal cell carcinoma (ccRCC) is driven by persistent HIF-2α transcription program initiated by VHL loss, yet molecular mediators sustaining this program are poorly defined. Using single-cell transcriptomics, we identified lysyl oxidase (LOX) as a driver of ccRCC progression, selectively enriched in a hypoxia/epithelial-mesenchymal transition (EMT) gene program associated with poor outcome. While LOX oxidizes and stabilizes HIF-2α by antagonizing HUWE1-mediated ubiquitination and degradation, thereby sustaining HIF-2α-driven transcription in cancer cells, it also remodels extracellular matrix (ECM) and promotes angiogenesis in the tumor microenvironment (TME). Genetic or pharmacological inhibition of LOX destabilizes HIF-2α, disrupts ECM, inhibits angiogenesis, and suppresses tumor initiation, growth, and metastasis in vivo. LOX inhibition enhances anti-angiogenic therapy response and remains effective in belzutifan-resistant HIF-2α G323E-mutant tumors. Nuclear LOX protein correlates with nuclear HIF-2α in high-grade patient tumors. Together, LOX coordinates HIF-2α transcription program with TME and is a therapeutic target in ccRCC.
Hypoxia is a defining feature of the tumor microenvironment and a key driver of malignant progression through transcriptional reprogramming of metabolic, angiogenic, and survival pathways. In this study, hypoxia-induced molecular responses were investigated in human hepatocellular carcinoma (HepG2) and breast adenocarcinoma (MCF-7) cells using cobalt(II) chloride (CoCl2) as a hypoxia mimetic. Cell viability profiling was performed to determine the optimal experimental concentration, followed by quantitative PCR analysis of hypoxia-related genes and miRNA-gene interaction network analysis. Cell viability profiling identified 100 µM CoCl2 as the optimal condition for downstream analyses. Quantitative PCR revealed robust induction of HIF-1α in both cell lines, indicating activation of hypoxic signaling. However, downstream responses differed markedly between cell types. MCF-7 cells exhibited significant upregulation of SLC2A1 and increased VEGFA and NFKB1 expression, consistent with activation of glycolytic and pro-angiogenic pathways. In contrast, HepG2 cells showed limited downstream transcriptional engagement despite elevated HIF1A expression. Furthermore, miRNA-gene interaction analysis revealed a dense regulatory network in MCF-7 cells, whereas HepG2 cells displayed a more restricted, VEGFA-centered miRNA profile. These findings demonstrate that chemical hypoxia induces cell-type-specific transcriptional and post-transcriptional responses in breast and liver cancer cells. The results suggest that miRNA-mediated regulation may contribute to differential tumor adaptation to hypoxic stress and highlight the importance of cellular context in hypoxia-associated signaling pathways.
Okan Sancer, Pınar Aslan Koşar, Uğur Şahin et al.· Drug and chemical toxicology...· 0 citations
ABSTRACT Background Cellular plasticity and epithelial–mesenchymal transition (EMT) promote the initiation and progression of non-small cell lung cancer (NSCLC). Thioredoxin reductase 1 (TXNRD1), a key redox enzyme, has been linked to malignancy, but its mechanism in NSCLC remains unclear. We examined whether TXNRD1 regulates TGF-β1 autocrine signaling to drive EMT and stemness. Materials Stage-progression gene profiles were analyzed in the TCGA and GEO databases with an emphasis on redox gene families. TXNRD1 was manipulated by overexpression or knockdown in A549, H226, and H1299 cells, followed by migration/invasion, spheroid assays, ELISA for cytokines, and RT-qPCR/Western blot for EMT markers. RNA-seq with pathway enrichment analyses was used to identify downstream programs. An orthotopic lung cancer mouse model was established using TXNRD1-WT cells, TXNRD1-deficient cells, and TXNRD1-deficient cells treated with TRi-1. Tumor progression was monitored by bioluminescence imaging at 6 and 12 weeks after transplantation. Results TXNRD1 expression was ~2-fold higher in advanced-stage NSCLC and was validated in tumor tissues. CRISPR/Cas9 or siRNA knockdown reduced EMT-associated genes and decreased TGF-β1 production in A549 and H226 cells. TXNRD1 overexpression increased EMT and stemness markers and produced larger, more compact spheres with higher sphere numbers in H1299 cells. RNA-seq indicated the TXNRD1 pathway activates the TGF-β1 pathway to promote EMT, motility, and stemness via an autocrine loop; knockdown or TXNRD1 inhibition suppressed metastatic tumor growth in vivo. Conclusions Our study identifies TXNRD1 as a crucial regulator of cellular plasticity and metastasis in NSCLC via the TGF-β1 pathway, suggesting that targeting TXNRD1 may reduce metastatic potential and improve patient survival.
Yaw-Dong Lang, Shin-Yuan Gu, Jou-Ho Shih et al.· Cancer Biology & Therapy· 0 citations
Summary Cervical cancer aggressiveness and therapeutic resistance are driven by metabolic reprogramming and redox imbalance. Within this context, NAD(P)H: quinone oxidoreductase 1 (NQO1), a critical regulator of cellular redox homeostasis and energy metabolism, is highly expressed in several types of cancer and is associated with poor prognosis; however, its role in cervical cancer remains unclear. This study demonstrates that NQO1 is significantly upregulated in cervical cancer, promoting proliferation, metastasis, and epithelial-mesenchymal transition (EMT). Mechanistically, NQO1 suppresses AMP-activated protein kinase (AMPK) phosphorylation to reduce reactive oxygen species (ROS), while stabilizing HIF1α by preventing its proteasomal degradation. Consequently, stabilized HIF1α upregulates sine oculis homeobox 1 (SIX1) to enhance glycolytic enzyme transcription, driving aerobic glycolysis. Functional rescue experiments demonstrated that knockdown of NQO1, HIF1α, or SIX1 significantly inhibited glycolytic flux, tumor growth, and metastasis in vivo. Thus, the NQO1/HIF1α-SIX1 axis orchestrates metabolic reprogramming and EMT to promote cervical cancer progression and is a promising therapeutic target.
Glioma represents one of the most aggressive tumors in the central nervous system, with clinical management facing significant challenges including high recurrence rates and therapeutic resistance. Ferroptosis, an iron-dependent form of cell death, holds potential for glioma treatment, yet tumor cells frequently develop evasion mechanisms. This study elucidates the molecular mechanisms by which hypoxic microenvironment confers ferroptosis resistance in glioma cells, focusing on the pivotal role of the HIF-1α/SREBP1 signaling axis and its downstream effectors FASN and SCD1. Our experimental results demonstrate that hypoxic conditions significantly upregulate HIF-1α expression and confer resistance to RSL3-induced ferroptosis. Mechanistic studies reveal that HIF-1α promotes SREBP1 activation, which subsequently upregulates FASN and SCD1 expression to suppress lipid peroxidation.Furthermore, the HIF-1α-specific inhibitor PX-478 effectively reverses hypoxia-induced ferroptosis resistance and significantly enhances tumor cell sensitivity to ferroptosis inducers. In vivo experiments confirm the potent antitumor effects of PX-478 combined with RSL3. This study systematically elucidates the role of the HIF-1α-SREBP1-FASN/SCD1 signaling axis in ferroptosis regulation in glioma, providing important theoretical foundations and experimental support for developing HIF-1α-targeted ferroptosis therapies.
Zhong-Jun Shen, Yao Zhao, Mingbo Jia et al.· Journal of Lipid Research· 0 citations
A comprehensive pan-cancer transcriptomic analysis together with functional assays reveal that miR-210-3p not only mediates classical hypoxic responses but also amplifies mitotic gene expression through activation of FOXM1, positioning miR-210-3p as a molecular integrator linking pseudohypoxia to mitotic dysregulation.
Jaime San-Juan-Guardado, María Turienzo-Durán, Álvaro Suárez-Priede et al.· Molecular Biomedicine· 0 citations
This work provides a powerful visualizable platform to dynamically study the crosstalk between HIF-1α and ferroptosis in liver cancer, facilitating the exploration of hypoxia-ferroptosis interplay in hepatocarcinogenesis and therapeutic response.
Kuo-Ye Tian, Peng Chang, Xiao-Yu Yang et al.· The FEBS Journal· 0 citations
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