Amphoterin-Induced Gene and Open Reading Frame 2 (AMIGO2) Interacts with CAPN2 and Promotes the Proliferation and Migration of Hypopharyngeal Cancer Cell

Background: Amphoterin-induced gene and open reading frame 2 (AMIGO2) has been reported to play a detrimental role in multiple cancer types. However, the precise role of AMIGO2 in hypopharyngeal squamous cell carcinoma (HPSCC) remains elusive. Methods: Bioinformatic analysis was employed to identify the differential expression and prognostic value of AMIGO2 in the head and neck cancer. Proliferation, apoptosis, and migration assays were then conducted after short hairpin RNA-mediated knockdown of AMIGO2 in FaDu cell line and in xenograft mouse model. Co-immunoprecipitation and mass spectrometry analysis were performed to determine the protein interaction between AMIGO2 and CAPN2. Rescue experiments with respect to the overexpression of CAPN2 were also performed. RNA sequencing after AMIGO2 knockdown with and without CAPN2 overexpression were conducted, followed by pathway enrichment analysis. Results: AMIGO2 expression was up-regulated in head and neck cancer and correlated with a poor prognosis. Functionally, HPSCC cell proliferation and migration were significantly inhibited in vivo and in vitro upon AMIGO2 knockdown. AMIGO2 binds to CAPN2 in cell context, and overexpression of CAPN2 could effectively reverse the inhibition from AMIGO2 knockdown. Bioinformatics analysis based on RNA sequencing indicated that the interaction between AMIGO2 and CAPN2 might be involved in multiple signaling pathways. Conclusions: Our work suggests that AMIGO2 promotes the proliferation and migration of HPSCC by interacting with CAPN2, implying that AMIGO2 can be therapeutically targeted to treat HPSCC. Overall design: RNA-seq analysis was performed on three groups of FaDu cells, i.e., AMIGO2 knockdown (KD_NC), AMIGO2 knockdown combined with CAPN2-overexpression (KD_OE), and normal controls (NC_NC).