Determination of the Immunomodulatory Role of OTOP2 in Colon Adenocarcinoma.

Abstract

Background: Otopetrin 2 (OTOP2) is a conserved ion channel protein that regulates cell signaling, growth, and development. Although the role of OTOP2 in tumor suppression has been reported in several studies of colon adenocarcinoma (COAD), characterized its immunomodulatory effects on tumors. Methods: We conducted a thorough analysis of OTOP2 expression and its association with clinicopathological characteristics, immune-related pathways, and immune-related molecules in individuals with COAD using data from The Cancer Genome Atlas (TCGA) and confirmed the findings with tissue microarrays (TMAs). We conducted in vitro assays to demonstrate the tumor suppressive effect of OTOP2 in COAD cells. Results: OTOP2 expression was abnormal in multiple types of tumors and was significantly downregulated in patients with COAD (P<0.001). Moreover, the presence of OTOP2 was linked to enhanced survival in individuals diagnosed with COAD. In vitro experiments showed that OTOP2 suppressed cell proliferation, migration, invasion, and adhesion. Gene set enrichment analysis of the TCGA database indicated that OTOP2 was positively correlated with antigen presentation pathways and T cell responses. The immunophenoscore (IPS) indicated a positive correlation between OTOP2 expression and MHC molecule expression (P<0.001) as well as between OTOP2 expression and the number of effector cells (P<0.01). Immunohistochemical analysis of the TMAs revealed strong associations between OTOP2 expression and MHC-I, TAP1, and TAP2 expression, and between OTOP2 expression and CD8+ T cell infiltration in COAD patients. Conclusion: In summary, our research emphasizes the role of OTOP2 as a tumor suppressor, suggesting its use as a prognostic indicator and predictor of response to immunotherapy in COAD patients.