基于生物信息学分析RNA结合蛋白SAMD4家族在乳腺癌中的表达和功能差异OA

Sterile alpha motif domain-containing protein 4(SAMD4)family is a group of evolutionarily highly conserved RNA-binding proteins,consisting of two members,SAMD4A and SAMD4B.Their core functions are associated with the regulation of RNA metabolism,while aberrant expression of both proteins may be in-volved in the occurrence and development of tumors.Recent studies have demonstrated that SAMD4A is down-regulated in breast cancer and exerts tumor-suppressive effects,but the function of SAMD4B in this disease remains unclear.This study systematically analyzed differences in expression and function between SAMD4A and SAMD4B in breast cancer using bioinformatics methods.Through integrated analysis of multiple data-bases,it was found that although SAMD4A and SAMD4B have highly homologous protein sequences and similar structural domains,their expression patterns in breast cancer are completely opposite:SAMD4A was downregulated in breast cancer tissues,and its low expression was associated with poor prognosis of patients,while SAMD4B was upregulated in breast cancer tissues,suggesting that the two proteins may have different functional properties.Further analysis showed that the methylation level of SAMD4A was significantly higher in breast cancer tissues than that in normal tissues,whereas SAMD4B methylation showed an opposite trend.In addition,through GO function,KEGG pathway enrichment and protein-protein interaction(PPI)network analyses of 40 genes co-expressed with SAMD4A and SAMD4B,three key genes(PDGFRA,COX7C and BRD4)regulated by the two proteins were identified as potentially involved in the regulation of breast cancer occurrence and development.Meanwhile,two upstream microRNAs(miRNAs)responsible for regulating the expression of SAMD4A and SAMD4B,respectively,and associated with breast cancer progression were also identified.Collectively,these results indicate that the RNA-binding proteins of the SAMD4 family exhibit distinct expression patterns and functions in breast cancer,suggesting that they may serve as important molecular markers for clinical diagnosis and prognosis of this disease.