KIAA1429/VIRMA promotes breast cancer proliferation and migration by stabilizing m6A-modified HAS2 RNA expression in cytosol

N6-methyladenosine (m6A) is the most abundant internal RNA modification in mRNA molecules and plays important roles in multiple important biological processes including cancer development. KIAA1429/VIRMA is an important component of m6A methyltransferase complex to facilitate depositing m6A modification in RNA molecules. Here we found that KIAA1429/VIRMA was overexpressed in breast cancer patients among other m6A related enzymes. Breast cancer patients with higher KIAA1429 expression have worse survival compared with control group. In addition, KIAA1429/VIRMA protein mislocated in cytosol in breast cancer tissues and cell lines. KIAA1429/VIRMA depletion reduced breast cancer cell proliferation and migration. Mechanism studies showed that cytosolic expressed KIAA1429/VIRMA interacted with m6A reader protein IGF2BP3 and stabilized expression of m6A-modified HAS2 expression. HAS2 is downstream of KIAA1429/VIRMA to mediate breast cancer cell proliferation and migration and has positive correlation with KIAA1429/VIRMA expression in cancer patients. Overall design: Control (NTC) MDA-MB-231 breast cancer cells, KIAA1429 KO MDA-MB-231 breast cancer cells, KIAA1429 KD MDA-MB-231 breast cancer cells, RNA-seq and MeRIP-Seq.