TSC22D2 interacts with PKM2 and inhibits cell growth in colorectal cancer.

We previously identified TSC22D2 (transforming growth factor β-stimulated clone 22 domain family, member 2) as a novel cancer-associated gene in a rare multi-cancer family. However, its role in tumor development remains completely unknown. In this study, we found that TSC22D2 was significantly downregulated in colorectal cancer (CRC) and that TSC22D2 overexpression inhibited cell growth. Using a co-immunoprecipitation (co-IP) assay combined with mass spectrometry analysis to identify TSC22D2-interacting proteins, we demonstrated that TSC22D2 interacts with pyruvate kinase isoform M2 (PKM2). These findings were confirmed by the results of immunoprecipitation and immunofluorescence assays. Moreover, overexpression of TSC22D2 reduced the level of nuclear PKM2 and suppressed cyclin D1 expression. Collectively, our study reveals a growth suppressor function of TSC22D2 that is at least partially dependent on the TSC22D2-PKM2-cyclinD1 regulatory axis. In addition, our data provide important clues that might contribute to future studies evaluating the role of TSC22D2.