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.
Abstract (not final)
MicroRNAs (miRs) are short, non-coding RNAs that regulate gene expression and control essential cellular processes such as cell cycle progression and apoptosis. Dysregulation of miRs expression levels 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 antago-miRs. However, limitations exist in regard to cellular uptake. A previous study, however, demonstrated that DNA nanostructures functionalized with small interfering RNA (siRNA) underwent cellular entry and executed targeted gene suppression suggesting strong therapeutic potential. Here, we report the fabrication of a rod-like and a block-like DNA nanostructure incorporated with complementary 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) through the molecular self-assembly process DNA origami. Proper assembly was confirmed via gel electrophoresis and transmission electron microscopy. Functionalization of miR-21 complementary DNA overhangs was confirmed via fluorescent typhoon 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 significant decreases in OSU-CLL cell viability relative to scrambled control overhang nanostructures as shown via fluorescent microscopy and flow cytometry. Moreover, the miR-21 complementary DNA overhang functionalized DNA nanostructures significantly increased PTEN mRNA and protein levels relative to scrambled control overhangs as shown via quantitative real time PCR and immunoblot analysis, respectively. Together, these findings suggest that the complementary miR-21 DNA overhang functionalized DNA nanostructures effectively sequester miR-21 and increase levels of PTEN to induce cytoxicity in OSU-CLL cells. Our results represent a promising antago-miR delivery 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!