Characterization of MNK1b DNA Aptamers That Inhibit Proliferation in MDA-MB231 Breast Cancer Cells

Abstract

Elevated expression levels of eukaryotic initiation factor 4E (eIF4E) promote cancer development and progression. MAP kinase interacting kinases (MNKs) modulate the function of eIF4E through the phosphorylation that is necessary for oncogenic transformation. Therefore, pharmacologic MNK inhibitors may provide a nontoxic and effective anticancer strategy. MNK1b is a truncated isoform of MNK1a that is active in the absence of stimuli. Using in vitro selection, high-affinity DNA aptamers to MNK1b were selected from a library of ssDNA. Selection was monitored using the enzyme-linked oligonucleotide assay (ELONA), and the selected aptamer population was cloned and sequenced. Four groups of aptamers were identified, and the affinities of one representative for rMNK1b were determined using ELONA and quantitative polymerase chain reaction. Two aptamers, named apMNK2F and apMNK3R, had a lower Kd in the nmol/l range. The secondary structure of the selected aptamers was predicted using mFold, and the QGRS Mapper indicated the presence of potential G-quadruplex structures in both aptamers. The selected aptamers were highly specific against MNK1, showing higher affinity to MNK1b than to MNK1a. Interestingly, both aptamers were able to produce significant translation inhibition and prevent tumor cell proliferation and migration and colony formation in breast cancer cells. These results indicate that MNK1 aptamers have an attractive therapeutic potential.

Laboratory evolution of artificially expanded DNA gives redesignable aptamers that target the toxic form of anthrax protective antigen

“…Interestingly, the G-rich region containing the two non-standard nucleotides appeared to form a large loop on top of the second stem. This suggested the presence of some form of higher-level three-dimensional folding beyond simple base-pairing, such as G-quadruplex structures, as seen previously for other aptamers (30,31). …”

Aptamer Internalization via Endocytosis Inducing S-Phase Arrest and Priming Maver-1 Lymphoma Cells for Cytarabine Chemotherapy

“…3A), which have been reported to be associated with aptamer stability and cellular functions 24-26. The G-quadruplex structure in aptamer HL-1 was further confirmed with Thioflavin T staining (Fig.…”

Lysine Restriction Affects Feed Intake and Amino Acid Metabolism via Gut Microbiome in Piglets

“…The relative expression was expressed as a ratio of the target gene to the control gene using the formula 2 -(∆∆Ct) , where ∆∆Ct=(Ct Target -Ct β-actin ) treatment -(Ct Target -Ct β-actin ) control . Relative expression was normalized and expressed as a ratio to the expression in the control group [24-26]. …”