Suppression of prostate cancer metastasis by DPYSL3-targeted saRNA

Abstract

Metastasis is the sole cause of cancer death and there is no curable means in clinic. Cellular protein CRMP4 (DPYSL3 gene) was previously defined as a metastasis suppressor in human prostate cancers since its expression is dramatically reduced in lymphatic metastatic diseases and DPYSL3 overexpression in prostate cancer cells significantly suppressed cancer cell migration and invasion. To develop a CRMP4-based antimetastasis therapeutic approach, the small activating RNA (saRNA) technique was utilized to enhance CRMP4 expression in prostate cancer cells. A total of 14 saRNAs were synthesized and screened in multiple prostate cancer cell lines. Two saRNAs targeting the isoform-2 promoter region were determined to have significant activating effect on DPYSL3 gene expression at the mRNA and protein levels. These saRNA also largely reduced prostate cancer cell migration and invasion in vitro and in vivo. Most significantly, PSMA aptamer-mediated prostate cancer cell homing of these saRNAs blocked distal metastasis in an orthotopic nude mouse model. In conclusion, our data demonstrated that saRNA-based DPYSL3 gene enhancement is capable of suppressing tumor metastasis in prostate cancer, which provides a potential therapeutic approach for cancer management.