IGFL2-AS1 knockdown enhances erastin-induced ferroptosis-associated changes in oral squamous cell carcinoma

Long non-coding RNA (lncRNA) IGFL2-AS1 has been implicated in oral squamous cell carcinoma (OSCC) progression, whereas its relationship to ferroptosis remains unclear. Erastin is a small-molecule ferroptosis inducer that inhibits system Xc-, reduces cystine uptake and glutathione availability, and thereby promotes lipid peroxide accumulation. We investigated whether IGFL2-AS1 modulates erastin-induced ferroptosis-associated changes through the miR-181a-5p/SLC7A11 axis.

Correlations among IGFL2-AS1, miR-181a-5p, and SLC7A11 were analyzed in public HNSC datasets using online bioinformatic tools. RNA immunoprecipitation (RIP)-qPCR and dual-luciferase assays were used to validate the interactions. Erastin-treated OSCC cell lines (Cal-27 and SCC15) were subjected to IGFL2-AS1 knockdown/overexpression or miR-181a-5p modulation for CCK-8 assays, and Cal-27 cells were further used for MDA, GSH, and Fe2+ measurements. Fluorescence staining and immunofluorescence analyses of ROS, SLC7A11, and FTH1 were further performed in Cal-27 cells. In vivo, tumor growth was monitored in xenografts derived from Cal-27 cells with stable IGFL2-AS1 knockdown and treated with erastin or antagomiR-181a-5p.

IGFL2-AS1 knockdown or miR-181a-5p overexpression increased the sensitivity of OSCC cells to erastin, as indicated by reduced viability. In Cal-27 cells, this was accompanied by increased MDA and Fe2+ levels and depleted GSH. Mechanistically, IGFL2-AS1 acted as a competing endogenous RNA for miR-181a-5p and regulated the expression of the ferroptosis-related protein SLC7A11. In Cal-27 cells, IGFL2-AS1 knockdown further enhanced erastin-associated ROS fluorescence and reduced SLC7A11 and FTH1 immunoreactivity, whereas miR-181a-5p inhibition partially reversed these changes. In vivo, IGFL2-AS1 silencing enhanced erastin-associated tumor suppression and reduced SLC7A11 expression, while antagomiR-181a-5p partly attenuated these effects.

The present data support that IGFL2-AS1 knockdown enhances erastin-induced ferroptosis-associated changes in OSCC, at least in part through the miR-181a-5p/SLC7A11 axis.