Single-Round DNA Aptamer Selection by Combined Use of Capillary Electrophoresis and Next Generation Sequencing: An Aptaomics Approach for Identifying Unique Functional Protein-Binding DNA Aptamers.

In DNA aptamer selection, existing methods do not discriminate aptamer sequences based on their binding affinity and function and the reproducibility of the selection is often poor, even for the selection of well-known aptamers like those that bind the commonly used model protein thrombin. In the present study, a novel single-round selection method (SR-CE selection) was developed by combining capillary electrophoresis (CE) with next generation sequencing. Using SR-CE selection, a successful semi-quantitative and semi-comprehensive aptamer selection for thrombin was demonstrated with high reproducibility for the first time. Selection rules based on dissociation equilibria and kinetics were devised to obtain families of analogous sequences. Selected sequences of the same family were shown to bind thrombin with high affinity. Furthermore, data acquired from SR-CE selection was mined by creating sub-libraries that were categorized by the functionality of the aptamers (e. g., pre-organized aptamers versus structure-induced aptamers). Using this approach, a novel fluorescent molecular recognition sensor for thrombin with nanomolar detection limits was discovered. Thus, in this proof-of-concept report, we have demonstrated the potential of a "DNA Aptaomics" approach to systematically design functional aptamers as well as to obtain high affinity aptamers.

[A case of spindle cell type hepatocellular carcinoma responding to hepatic intra-arterial infusion chemotherapy].

We report herein a case of spindle cell type hepatocellular carcinoma responding to hepatic intra-arterial infusion chemotherapy. A 50-year-old woman was hospitalized for right epigastralgia. A computed tomography scan demonstrated cloudy liver tumor with a diameter of 12 cm in S5 and S8. Surgery was performed based on the diagnosis of liver tumor. However, because the tumor was also present in the left lobe, we did only a biopsy for a part of tumor. From the pathological findings, this was diagnosed as a spindle cell type hepatocellular carcinoma. After the operation, hepatic intra-arterial injection therapy of continuous infusion with 5-FU was conducted for two weeks. A small reduction in the tumor was seen with computed tomography after the completion of two courses.