Abstract: Objective To explore the expression of ANKRD6 in colon adenocarcinoma (COAD) and its implications for prognosis and treatment of COAD. Methods We investigated the differential expression of ANKRD6 in 20 pairs of COAD and adjacent tissues using immunohistochemistry and in colon cancer cell lines and normal colon cells using real-time quantitative PCR. Gene expression matrices, immune infiltration data, and clinical information of 521 COAD patients and 41 normal tissues were obtained from the TCGA database for analyzing the association of ANKRD6 expression with clinicopathological features, gene set enrichment, and immune infiltration in COAD using R software. The prognostic factors of COAD were evaluated using univariate and multivariate Cox regression and Kaplan-Meier analyses, and a prognostic nomogram containing ANKRD6 was constructed. Western blotting, CCK-8 assay, scratch assay and Transwell assay were performed to assess the effects of ANKRD6 knockdown on biological activities of COAD cells. Results ANKRD6 was highly expressed in COAD cell lines and upregulated in COAD tissues with higher malignancy (P<0.05). Increased ANKRD6 expression was significantly correlated with decreased overall survival and disease-free survival of COAD patients (P<0.05). Univariate and multivariate Cox regression analyses indicated that ANKRD6 expression was significantly correlated with the overall survival rate of COAD patients (P<0.05). The constructed prognostic nomogram showed a C-index value of 0.739 and effectively predicted the 1- , 3- , and 5-year survival of the patients. ANKRD6 expression was positively correlated with immune infiltration of macrophages (P<0.05) and negatively correlated with Th17 cells and other immune cell infiltration (P<0.05). Bioinformatic analysis suggested that ANKRD6 was mainly enriched in Wnt, vascular endothelial growth factor receptor, and calcium signaling pathways in COAD. In cultured COAD cells, ANKRD6 knockdown significantly suppressed cell proliferation, migration, and invasion (P<0.05). Conclusion High ANKRD6 expression is an indicator for poor prognosis of COAD, and ANKRD6 may serve as a potential biomarker as well as a therapeutic target for diagnosis and treatment of COAD.

Key words: colon adenocarcinoma; ANKRD6; tumor immune infiltration; prognosis