PX-478

Hypoxia is a hallmark of the tumor microenvironment, but its role in immune evasion in esophageal squamous cell carcinoma (ESCC) remains to be fully elucidated. Here, we demonstrate hypoxia inversely correlated with anti-tumor immune signatures and CD8⁺ T cell infiltration in clinical samples and murine models. Functionally, reducing hypoxia with the agents TH-302 or PX-478 in the AKR model enhanced intratumoral CD8⁺ T cell infiltration and increased their expression of Granzyme B, IFNγ, and TNFα. Mechanistically, hypoxia-induced immune suppression was dependent on protein lactylation. Inhibiting lactylation reversed the hypoxic suppression of CD8⁺ T cell function and abrogated the hypoxia-driven transcriptional program, which involved pathways like glycolysis, TGFβ, and Notch signaling. This lactylation-dependent regulation operated by facilitating the formation of the HIF-1 transcription complex. Specifically, mass spectrometry identified lactylation at the K172 site of HIF-1α, which was crucial for its binding to HIF-1β and subsequent target gene activation. Furthermore, in a preclinical ESCC model, pharmacological inhibition of HIF-1α with PX-478 synergized with anti-PD-1 therapy, leading to superior tumor control and enhanced CD8⁺ T cell cytotoxicity. Our study identifies HIF-1α K172 lactylation as a pivotal mechanism of hypoxia-mediated immune escape in ESCC, suggesting a therapeutic strategy to improve immunotherapy.

JOURNAL/nrgr/04.03/01300535-202606000-00052/figure1/v/2026-04-16T195327Z/r/image-tiff Epilepsy is a prevalent neurological disorder in which hippocampal neuronal damage, particularly ferroptosis, plays a critical role. Previous studies have shown that hypoxia-inducible factor 1α is considered an important regulator of cellular stress responses and has been confirmed to play a critical role in the occurrence of various diseases. However, the mechanisms by which hypoxia-inducible factor 1α is related to epilepsy and neuronal ferroptosis remain unclear. In this study, we used a pentylentetrazole-induced chronic epilepsy mouse model and treated the mice with intraperitoneal administration of PX-478, a hypoxia-inducible factor-1α inhibitor. Our results showed that PX-478 significantly prolonged the latency of epilepsy, reduced seizure severity, and shortened seizure duration. PX-478 also alleviated neuronal damage in the hippocampal CA1 and CA2 regions, reduced levels of reactive oxygen species and malondialdehyde, and increased levels of superoxide dismutase, catalase, and glutathione peroxidase. Transmission electron microscopy showed that PX-478 treatment reduced mitochondrial damage in the hippocampal neurons of epileptic mice, and significantly improved mitochondrial length and area. Additionally, PX-478 preferentially reduced Fe 2+ levels and the expression of cyclooxygenase-2, ferritin heavy chain 1 and transferrin in the hippocampus of epileptic mice. It also inhibited the activity of the hypoxia-inducible factor 1α/heme oxygenase-1 pathway. In summary, these findings suggest that PX-478 has the potential to treat epilepsy by inhibiting the hypoxia-inducible factor 1α/heme oxygenase-1 pathway, alleviating oxidative stress, and reducing ferroptosis in hippocampal neurons.