The prognostic significance and regulatory networks of DAP3 in hepatocellular carcinoma microenvironment based on bioinformatics analysis

Background: Death-associated protein 3 (DAP3) is a GTP-binding protein in the component of the small subunit of the mitochondrial ribosome. Abnormal expression of DAP3 potentially correlates with carcinogenesis. However, the specific functions of DAP3 in hepatocellular carcinoma (HCC) are still not clarified.Methods: The expression of DAP3 in different cancer types was analyzed using TIMER and Oncomine, and DAP3 expression in HCC was detected using Oncomine, GEPIA and UALCAN. DAP3 promoter methylation was shown via MEXPRESS. The effect of DAP3 on HCC prognosis was analyzed via Kaplan-Meier plotter, GEPIA and UALCAN. Moreover, co-expressed genes with DAP3 and their regulators, kinases, miRNA and transcription factor targets were identified using LinkedOmics. Furthermore, cBioPortal was used to detect the genetic alteration of DAP3. Finally, TIMER was utilized to evaluate the correlations between DAP3 and immune cell infiltration, while the correlation between DAP3 and three immune factors was detected through TIDISB.Results: DAP3 expression was significantly high in several tumor tissues, including HCC. The promoter methylation level of DAP3 in HCC tissues was remarkably lower compared with normal tissues. Additionally, high DAP3 expression was related to overall survival (OS). Functional network analysis indicated that DAP3 regulated the translational elongation, ribonucleoprotein complex biogenesis, tRNA metabolic process and mitochondrial respiratory chain complex assembly. Moreover, DAP3 expression represented strong correlations with the immune cell infiltration and immune factors in HCC. Conclusions: Our results indicated that DAP3 acted as a potential prognostic marker in HCC, laying a groundwork for further study of DAP3 in HCC.