LAUSR

It has been established that Cutaneous T‐Cell lymphomas (CTCL) are caused by the monoclonal proliferation of T lymphocytes in the skin. This heterogeneous group of diseases represents a significant source of distress to patients since the diagnosis and treatment are often challenging. As one of the most abundant internal modifications in mRNA in higher eukaryotes, N6‐methyladenosine (m6A) is widely recognized to affect the development and progression of cancers. However, knowledge on the involvement of m6A in CTCL is still limited. In this work, we revealed the role of METTL3‐mediated m6A modification in CTCL progression. ELISA, western blot, and qRT‐PCR assays demonstrated that METTL3 was significantly downregulated in CTCL cells both in vivo and in vitro. CCK‐8, EdU, flow cytometry, and transwell assays showed that the decline in METTL3 levels was responsible for CTCL cell proliferation and migration. Furthermore, using small interfering RNAs against METTL3 and the RIP assay, we showed that CDKN2A was a key regulator during this process in vitro and in vivo, and insufficient methylation modification blocked the interaction between CDKN2A and m6A reader IGF2BP2, resulting in mRNA degradation. To the best of our knowledge, this is the first study to depict the role of m6A in CTCL development and provide potential bio‐targets for therapy.