Peptides have been in the limelight, as therapeutic agents for cancer treatment
through various applications due to their high target selectivity and
exceptional ability to penetrate the cell membrane. Recent studies have revealed
that synthesized peptides bind to hairpin structures of RNA that affect their
activities such as changing the efficacy of microRNA maturation.
MicroRNA-mediated p53 activation by the microRNA-29 (miR29) family is one of the
most important regulatory pathways in cancer therapeutics. By targeting the
suppressors of p53, a tumor suppressor protein, miR29 induces apoptosis of
cancer cells through p53 stabilization. Here, we identify a novel synthesized
amphiphilic peptide, LK-L1C/K6W/L8C, which enhances expression of miR29b and
promotes p53 activity. In the presence of LK-L1C/K6W/L8C, pre-miR29b
preferentially forms a complex with the Dicer protein through interaction of
LK-L1C/K6W/L8C with the terminal loop region of pre-miR29b, leading to an
increase in Dicer processing. Furthermore, LK-L1C/K6W/L8C stimulates apoptosis
by improving p53 stability in miR29-inducible HeLa and MCF7 cells. Collectively,
our study shows that a peptide can directly influence the miR29b-mediated p53
activation pathway in cancer cells. Therefore, our findings provide the basis
for a new, potentially promising peptide-based drug for cancer therapy.