Increasing evidence indicates that mRNAs are often subject to posttranscriptional modifications. Among them, N6-methyladenosine (m6A), which has been shown to play key roles in RNA splicing, stability, nuclear export, and translation, is the most abundant modification of RNA. Extensive studies of m6A modification of mRNAs have been carried out, while little is known about m6A modification of long non-coding RNAs (lncRNAs). Recently, several studies reported m6A modification of lncRNAs. In this review, we focus on these m6A-modified lncRNAs and discuss possible functions of m6A modification.

Circular RNAs (circRNAs) are playing emerging role in the pathogenesis of cancers, but the mechanisms still unknown. In the recent issue of the Nature Communications, Chen and colleagues have demonstrated that YTHDC1 facilitates N6-methyladenosine modified circNSUN2 cytoplasmic export and the circNSUN2/IGF2BP2/HMGA2 complex stabilizes HMGA2 to promote colorectal liver metastasis. These discoveries not only expand our understanding of circRNAs biology in tumor, but also demonstrate that m6A modification plays a key role for circRNAs in RNA metabolism. Therefore, these findings indicate that circRNAs may be a new approach for therapeutic target of cancers.