- Authors: Cogoi, S., Zorzet, S., Rapozzi, V., Geci, I., Pedersen, E. B., Xodo, L. E.
- Year: 2013
- Journal: Nucleic Acids Res 41 4049-64
- Applications: in vitro / in vivo / LNA, DNA / in vivo-jetPEI, jetPEI
- Cell type: PANC-1
Description: Human pancreatic carcinoma cells
2 nmol (corresponding to 27 µg) of modified oligonucleotide was delivered with in vivo-jetPEI at a N/P of 6 through intratumoral injection, on day 1, 6 and 11.
KRAS mutations are primary genetic lesions leading to pancreatic cancer. The promoter of human KRAS contains a nuclease-hypersensitive element (NHE) that can fold in G4-DNA structures binding to nuclear proteins, including MAZ (myc-associated zinc-finger). Here, we report that MAZ activates KRAS transcription. To knockdown oncogenic KRAS in pancreatic cancer cells, we designed oligonucleotides that mimic one of the G-quadruplexes formed by NHE (G4-decoys). To increase their nuclease resistance, two locked nucleic acid (LNA) modifications were introduced at the 3'-end, whereas to enhance the folding and stability, two polycyclic aromatic hydrocarbon units (TINA or AMANY) were inserted internally, to cap the quadruplex. The most active G4-decoy (2998), which had two para-TINAs, strongly suppressed KRAS expression in Panc-1 cells. It also repressed their metabolic activity (IC50 = 520 nM), and it inhibited cell growth and colony formation by activating apoptosis. We finally injected 2998 and control oligonucleotides 5153, 5154 (2 nmol/mouse) intratumorally in SCID mice bearing a Panc-1 xenograft. After three treatments, 2998 reduced tumor xenograft growth by 64% compared with control and increased the Kaplan-Meier median survival time by 70%. Together, our data show that MAZ-specific G4-decoys mimicking a KRAS quadruplex are promising for pancreatic cancer therapy.