PLEK2 functions as a co-factor of YTHDF2 to enhance TYMS mRNA stability in colorectal cancer

High expression of nucleotide synthetic enzyme thymidylate synthase (TYMS) is responsible for the resistance to fluorouracil (FU) treatment and worse survival in colorectal cancer. Herein, we revealed that Pleckstrin-2 (PLEK2), highly expressed in CRC, enhanced TYMS mRNA stability via its interaction with YTHDF2 in a m6A-dependent manner. Silencing of PLEK2 led to the downregulation of TYMS, and consequent inhibition of CRC cell proliferation via the cellular senescence. Additionally, PLEK2 is also required for CRC cell migration, invasion and stemness-like properties. PLEK2 inhibition is sufficient to ameliorate the progression of CRC. Moreover, loss of PLEK2 inhibited AOM/DSS-induced colonic tumorigenesis in vivo. Together, our study identified PLEK2 as a key regulator for the progress of CRC via the regulation of TYMS expression, and demonstrated that PLEK2 is a novel therapeutic target for CRC. 1X107 HCT116 cells transduced with retroviruses encoding HA tagged PLEK2 and empty vector were collected and lysed according to the instructions of RIP Immunoprecipitation Kit (Geneseed, P0101). Briefly, Agarose beads coated with 2µg of HA antibodies against human PLEK2 were incubated with prepared cell lysates overnight at 4°C. RNA was eluted by 15 µL of RNase-free water in the following steps, then ribominus rRNA were depleted by the rRNA depletion kits (Thermo, K155001), for high-throughput sequencing, the libraries were prepared following the manufacturer’s instructions and applied to Illumina NovaSeq 6000 system for 150 nt paired-end sequencing (Novogene).