Placental extract contains several biologically active compounds, and pharmacological induction of placental extract has therapeutic effects, such as improving liver function in patients with hepatitis or cirrhosis. Here, we searched for novel molecules with an anti-tumor activity in placental extracts. Active molecules were separated by chromatographic analysis, and their antiproliferative activities were determined by a colorimetric assay. We identified aspartic acid and glutamic acid to possess the antiproliferative activity against human hepatoma cells. Furthermore, we showed that the combination of aspartic acid and glutamic acid exhibited enhanced antiproliferative activity, and inhibited Akt phosphorylation. We also examined in vivo tumor inhibition activity using the rabbit VX2 liver tumor model. The treatment mixture (emulsion of the amino acids with Lipiodol) administered by hepatic artery injection inhibited tumor cell growth of the rabbit VX2 liver. These results suggest that the combination of aspartic acid and glutamic acid may be useful for induction of tumor cell death, and has the potential for clinical use as a cancer therapeutic agent.
Hypoxanthine is an unnatural base that can potentially pair with all natural nucleobases. While hypoxanthine in DNA exhibits marginal preference for pairing with cytosine (C), little is known about its pairing behavior in other DNA analogues. In this study, we synthesized a hypoxanthine-containing monomer and incorporated it into pyrrolidinyl peptide nucleic acid with α/β-peptide backbone derived from D-prolyl-(1S,2S)-2-aminocyclopentanecarboxylic acid (acpcPNA). DNA binding studies clearly revealed that hypoxanthine in acpcPNA behaves like G-analogue because it can specifically form a stable base pair with dC in DNA. The ability to replace G by hypoxanthine without affecting the base pairing properties of acpcPNA can solve a number of problems associated with G-rich acpcPNA including difficult synthesis, formation of secondary structures and fluorescence quenching.
Whole-column fluorescence-imaged CIEF was applied to study protein-protein binding reaction. A homemade whole-column fluorescence-imaged CIEF experimental setup was built, and its CIEF performance was evaluated with native fluorescent protein green fluorescence protein and fluorescently labeled proteins (bovine albumin, human albumin, and BSA). pIs, focusing time, detection limits, and linear quantitative range of the proteins were obtained. Furthermore, the method was used to study FITC-protein A-human IgG binding reaction. Experimental results showed that the apparent binding ratio of the FITC-protein A to human IgG was 1:2, and pI of the binding conjugates were about 6.3-6.5. No binding reaction was found between green fluorescence protein and the fluorescent-labeled proteins.
We developed a novel method for analyzing RNA sequences, deemed triplet analysis, and applied the method in an in vitro RNA selection experiment in which HIV-1 Tat was the target. Aptamers are nucleic acids that bind a desired target (bait), and to date, many aptamers have been identified by in vitro selection from enough concentrated libraries in which many RNAs had an obvious consensus primary sequence after sufficient cycles of the selection. Therefore, the higher-order structural features of the aptamers that are indispensable for interaction with the bait must be determined by additional investigation of the aptamers. In contrast, our triplet analysis enabled us to extract important information on functional primary and secondary structure from minimally concentrated RNA libraries. As a result, by using our method, an important unpaired region that is similar to the bulge of TAR was readily predicted from a partially concentrated library in which no consensus sequence was revealed by a conventional sequence analysis. Moreover, our analysis method may be used to assess a variety of structural motifs with desired function.
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