Abstract 4657: MB21D2 amplification and recurrent mutation exhibit oncogenic activity through centrosome and cilia alteration

MB21D2 (Mab-21 containing domain 2), a member of the Mab family, is predicted to form protein complexes with different partners, thus performs diverse functions in cells. In silico analyses using TCGA data revealed MB21D2 amplification/overexpression in various types of human cancer and correlated with poor survivals in patients with head and neck and endometrial cancer. More interestingly, a recurrent Q311E mutation was found in the Mab-21 domain critical for protein-protein interactions and downstream signaling. When expressed in oral cancer TW206 and CAL27 cells (low endogenous MB21D2), wild-type MB21D2 moderately increased cell proliferation, migration, and invasion as compared to the vector control. Significantly, the mutant variant (Q311E) showed stronger oncogenic effects on those processes and formed bigger spheres in a 3-D culture condition. Data mining, functional network predictions, and Western blotting confirmed the involvement of MB21D2 in centrosome-associated ciliogenesis via a crosstalk between PIK3CA and PKA (GSK and CREB) signaling pathways. Blockage of such interactome by specific inhibitors against PIK3CA or PKA reduced oncogenic activities mediated by MB21D2. Our data therefore suggest MB21D2 amplification/overexpression or the Q311E mutation as cancer drivers promoting cancer development through alteration of centrosome and primary cilia activity. Citation Format: Daniel Esguerra Gracilla, Praveen Kumar Korla, Louis Lai, Jim Jinn-Chyuan Sheu. MB21D2 amplification and recurrent mutation exhibit oncogenic activity through centrosome and cilia alteration [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4657.