Interdependent roles for growth differentiation factor-15 (GDF15) and LIMS1 in regulating cell migration:...

Colorectal cancer (CRC) ranks second in mortality worldwide while metastasis accounts for most CRC-related deaths. Thus, understanding cell migration, a crucial step in metastasis, is imperative for developing new therapies. Growth Differentiation Factor-15 (GDF15), a member of the Transforming Growth Factor β superfamily, is overexpressed in CRC and promotes metastasis with a so far unknown mechanism. LIMS1 is a cell-matrix adhesion prosurvival protein that is also overexpressed in CRC and localized at the tumor invasive front, while bioinformatics analysis shows that both genes exhibit the same expression pattern in metastatic CRC samples. In the present study, treatment of low-aggressiveness HT29 CRC cells with human recombinant GDF15 (hrGDF15) led to increased LIMS1 expression, increased mRNA level of RhoGTPases RAC1 and RHOA but not CDC42, and increased migration. Conversely, GDF15 or LIMS1-siRNA-mediated silencing in invasive HCT116 cells resulted in downregulation of LIMS1 and GDF15 respectively, decreased RAC1, and RHOA as well as reduced cell migration, which were fully restored by hrGDF15 treatment both in GDF15 and LIMS1-siRNA-treated cells. Our findings indicate that GDF15 and LIMS1 have an interdependent role in the migration process which renders them potent targets for the development of novel therapeutic strategies to inhibit metastatic spread.