OhioMOD is Ohio State's undergraduate biomolecular design team. The team participates in the BIOMOD international competition each year at Harvard University. The 2014 project will use a folded DNA structure to control miRNA gene regulation in cancer.
MicroRNAs (miRs) are short, non-coding RNAs that regulate gene expression and control essential cellular
processes, such as cell cycle progression and apoptosis, through interactions with messenger RNA.
Dysregulation of miR expression levels can promote tumorigenesous either by elevating oncogene or silencing
tumor suppressor gene levels implicating miRs as an attractive therapeutic target. One therapeutic approach is
to decrease levels of miRs that target tumor suppressor genes such as PTEN to ultimately promote apoptosis
by complementary base pair antagonism via antisense DNA, but limitations exist in regard to antisense DNA
cellular delivery. A previous study demonstrated that DNA nanostructures functionalized with small interfering
RNA (siRNA) underwent efficient cellular entry and executed targeted gene suppression suggesting strong
potential for DNA nanostructures as a nucleotide delivery vehicle. Here, we report the fabrication of a rod-like
and a block-like DNA nanostructure incorporated with DNA overhangs capable of binding and sequestering
miR-21, a PTEN targeting miR that is overexpressed in a variety of malignancies including chronic lymphocytic
leukemia (CLL). Proper assembly was confirmed via gel electrophoresis and transmission electron microscopy.
Incorporation and functionality of DNA overhangs complementary for miR-21 was confirmed via fluorescent
gel imaging. In addition, DNA nanostructures were shown to enter the endolysosomal pathway as revealed
via fluorescent microscopy. Furthermore, miR-21 complementary DNA overhang functionalized structures
induced marked decreases in OSU-CLL cell viability relative to scrambled control overhang nanostructures as
shown via fluorescent microscopy. Future work will directly investigate expression levels of PTEN mRNA and
protein using quantitative real time PCR and immunoblot analysis respectively. Our current findings suggest
that the complementary miR-21 DNA overhang functionalized DNA nanostructures effectively sequester miR-
21 to induce cytoxicity in OSU-CLL cells. Our results represent a promising antisense DNA delivery therapeutic
approach in a CLL leukemia model with implications to a variety of human malignancies.
The 2014 video is coming soon. Until then, enjoy OhioMOD's videos from the past two years!