BACKGROUND
Oxidative stress and ferroptosis play critical roles in the pathogenesis of intervertebral disc degeneration (IVDD). Thonningianin A (TA) is a complex polyphenolic ellagitannin found in plants like Thonningia sanguinea, and it exhibits free radical scavenging, anti-superoxide anion generation and metal-chelating activities. However, whether it can inhibit oxidative stress, ferroptosis and the progression of IVDD remains unclear.
PURPOSE
This study aimed to elucidate the molecular mechanism by which TA alleviates IVDD, specifically regarding oxidative stress and ferroptosis, and to validate these mechanisms in both cellular and animal models.
METHODS
An RSL3-induced nucleus pulposus cells (NPCs) ferroptosis model was established, with rescue using Fer-1, DFO and various concentrations of TA along with siRNA validation. Ferroptosis, oxidative stress and extracellular matrix (ECM) related proteins were assessed by western blot, immunofluorescence, fluorescent probes, molecular docking, molecular dynamics simulations and DFT binding energy analysis. In vivo, a rat tail puncture IVDD model was treated with TA or Fer-1, and evaluated by X-ray, MRI, Safranin-O/fast green (S-O) staining, Hematoxylin and Eosin (HE) staining and immunohistochemistry.
RESULTS
Mechanistic studies revealed that TA activates adenosine monophosphate-activated protein kinase (AMPK) phosphorylation and promotes the nuclear translocation of nuclear factor erythroid 2-related factor 2 (Nrf2) and subsequently upregulates the expression of glutathione peroxidase 4 (GPX4), thereby inhibiting oxidative stress, ECM degradation and ferroptosis. Additionally, TA modulates intracellular iron homeostasis by chelating Fe²⁺, thereby further attenuating ferroptosis. In a rat model, local intradiscal injection and intraperitoneal administration of TA effectively inhibited the progression of IVDD.
CONCLUSION
TA inhibits oxidative stress, ECM degradation and ferroptosis in NPCs by activating the AMPK/Nrf2/GPX4 axis and chelating Fe²⁺, thereby suppressing the progression of IVDD.
BACKGROUND
Colorectal cancer (CRC) is a common malignancy worldwide, and its progression is associated with dysregulated signaling pathways. Fibroblast growth factor receptor 2 (FGFR2) is frequently overexpressed in CRC and correlated with poor prognosis, but whether it mediates hypoxia-inducible factor-1α (HIF-1α) to promote tumor progression remains unclear.
METHODS
The expression and prognostic value of FGFR2 and HIF-1α in CRC were analyzed via bioinformatics. Clinicopathological specimens were obtained and immunohistochemical staining was performed to explore the correlations between FGFR2 and HIF-1α expression and the clinicopathological features of CRC patients. Using CRC cell lines (HCT116 and NCI-H716), cell proliferation, transwell, wound healing, western blotting, gene activation and knockdown experiments were used to assess the effects of FGFR2 expression on cell proliferation, migration and invasion, as well as phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) pathway activity and HIF-1α expression level. A mouse xenotransplantation model was used to further clarify the regulatory effects of changes in FGFR2 expression on PI3K/AKT/mTOR pathway activity, HIF-1α expression level and CRC tumor growth in vivo.
RESULTS
In this study, immunohistochemical staining of tumor tissues from 72 patients with CRC confirmed that the expression level of HIF-1α in cancer tissues was higher than that in normal tissues. Bioinformatics analysis and clinicopathological analysis confirmed that the overexpression of the FGFR2 and HIF-1α genes were the independent risk factors affecting the prognosis of CRC and that the overexpression of HIF-1α was positively correlated with the increase of tumor size and FGFR2 expression. The in vitro results of this study show that FGFR2 mediates HIF-1α and affects CRC cell proliferation, migration and invasion, which is consistent with the results of bioinformatics analysis. In vitro experiments involving FGFR2 overactivation and knockdown demonstrated that FGFR2 primarily functions in regulating the PI3K/AKT/mTOR signaling pathway, which was further verified by xenotransplantation mouse model. Knockdown of FGFR2 expression curbed the growth of CRC tumors through downregulating the PI3K/AKT/mTOR signaling pathway and HIF-1α expression level.
CONCLUSION
FGFR2 mediates the expression of HIF-1α via activating the PI3K/AKT/mTOR signaling pathway, thereby enhancing the proliferation, migration, and invasion of CRC cells. These findings suggest that FGFR2 may serve as potential therapeutic targets for the treatment of CRC.
Yiyang Hu, Liuxu Yao, Yuhong Li et al.· Tissue & Cell· 0 citations
