Hypoxic stabilization of RIPOR3 mRNA via METTL3-mediated m6A RNA methylation drives breast tumor growth and metastasis [m6A-seq-T47D]

N6-methyladenosine (m6A) modification is the most abundant internal mRNA modification in eukaryotes. Hypoxia induces reprogramming of m6A epitranscriptome, but the detail underlying regulator mechanism remains elusive in breast cancer. Here we reported that hypoxia induced elevated m6A modification involved in tumor progression. m6A- sequencing (m6A-seq) combined with RNA sequencing (RNA-seq) identified RIPOR3 as a key target gene of m6A modification under hypoxic stress. Hypoxia-induced increased of RIPOR3 m6A levels promoted its mRNA stability and expression, thereby facilitating the progression and metastasis of breast cancer. Besides, RIPOR3 was overexpressed in breast cancer cells and breast tumor tissues, and elevation of RIPOR3 expression was associated with poor prognosis. Mechanistically, RIPOR3 bound to EGFR and the interaction was enhanced under hypoxia, promoting the activation of the EGFR downstream PI3K-AKT signaling pathway. Altogether, our studies reveal that RIPOR3 responds to hypoxic stress to promote EGFR-PI3K-AKT signal pathway, facilitating breast cancer progression and metastasis, thus presenting itself as a potential therapeutic target. Overall design: m6A-modified sites in T47D cells which were treated in normoxic incubator or hypoxic work station (5% CO2,1% O2,37°C) for 24 hours.