Therapeutic efficacy of modified anti-miR21 in metastatic prostate cancer.

Despite improved therapeutic efficacy of the locked nucleic acid (LNA)- and peptide nucleic acid (PNA)-modified antisense microRNAs (anti-miRs), their wider application in clinical practice is still not thoroughly investigated. This study aimed to investigate the stability and therapeutic efficacy of the modified LNA- and PNA-type anti-miRs in a murine prostate cancer model under various treatment conditions. After verifying the anti-cancer potential of anti-miR21 by targeting tumor suppressor PTEN, the potential of the modified LNA- and PNA-type anti-miR21s was compared in vitro and in vivo. We found that PNA-type anti-miR21 showed better stability and therapeutic efficacy in the xenografted mouse tumor model than the LNA-type anti-miR21. Furthermore, PNA-type anti-miR21 treatment showed reduced tumor metastasis. This study may serve as a ground for exploring diverse choices in therapeutic oligonucleotide modification techniques to improve cancer treatment.