METTL3-mediated deficiency of lncRNA HAR1A drives non-small cell lung cancer growth and metastasis by promoting ANXA2 stabilization.

ABSTRACT

We previously reported lncRNA HAR1A as a tumor suppressor in non-small cell lung cancer (NSCLC). However, the delicate working mechanisms of this lncRNA remain obscure. Herein, we demonstrated that the ectopic expression of HAR1A inhibited the proliferation, epithelial-mesenchymal transition (EMT), migration, and invasion of NSCLC cells and enhanced paclitaxel (PTX) sensitivity in vitro and in vivo. We identified the oncogenic protein annexin 2 (ANXA2) as a potential interacting patterner of HAR1A. HAR1A overexpression enhanced ANXA2 ubiquitination and accelerated its degradation via the ubiquitin-proteasome pathway. We further uncovered that HAR1A promoted the interaction between E3 ubiquitin ligase TRIM65 and ANXA2. Moreover, the ANXA2 plasmid transfection could reverse HAR1A overexpression-induced decreases in proliferation, migration, and invasion of NSCLC cells and the activity of the NF-κB signaling pathway. Finally, we found that HAR1A loss in NSCLC might be attributed to the upregulated METTL3. The m6A modification levels of HAR1A were increased in cancer cells, while YTHDF2 was responsible for recognizing m6A modification in the HAR1A, leading to the disintegration of this lncRNA. In conclusion, we found that METTL3-mediated m6A modification decreased HAR1A in NSCLC. HAR1A deficiency, in turn, stimulated tumor growth and metastasis by activating the ANXA2/p65 axis.