Biological effect of ribosomal protein L32 on human breast cancer cell behavior

Breast cancer (BC) is the most common malignancy among women worldwide. However, identifying effective biomarkers for the diagnosis and treatment of BC is challenging. Based on our previously developed ‘humanized’ mouse model of BC, microarray expression analysis was performed and multiple differentially expressed genes, including ribosomal protein (RP) L32, were screened. Recent reports have revealed that RPs are relevant to the development and progression of cancer. However, the expression and function of RPL32 in BC remains unknown. Therefore, in the present study, the role of RPL32 in the development of BC was explored. Immunohistochemical staining and reverse transcription-quantitative PCR were used, and it was found that RPL32 was upregulated in human BC tissues and cells. Cell Counting Kit-8, cell invasion and migration assays were performed, which demonstrated that RPL32 knockdown using lentivirus-delivered small interfering RNA inhibited the migration and invasion of BC cells in vitro and in vivo (nude mouse model). Moreover, western blotting showed that RPL32 knockdown decreased the expression levels of matrix metalloproteinase (MMP)-2 and MMP-9. Thus, the present findings indicated a potential oncogenic role of RPL32, suggesting that it may be a novel target for molecular targeted therapy in patients with BC.