We recently have established a successful xenograft model of human glioblastoma cells by enriching hyaluronic acid-dependent spheroid-forming populations termed U251MG-P1 cells from U251MG cells. Since U251MG-P1 cells have been confirmed to express CD44 along with principal stemness marker genes, OCT3/4, SOX2, KLF4 and Nanog, this CD44 expressing population appeared to majorly consist of undifferentiated cells. Evaluating the sensitivity to anti-cancer agents, we found U251MG-P1 cells were sensitive to doxorubicin with IC50 at 200 nM. Although doxorubicin has serious side-effects, establishment of an efficient therapy targeting undifferentiated glioblastoma cell population is necessary. We previously designed a chlorotoxin peptide fused to human IgG Fc region without hinge sequence (M-CTX-Fc), which exhibited a stronger growth inhibitory effect on the glioblastoma cell line A172 than an original chlorotoxin peptide. Combining these results together, we designed M-CTX-Fc conjugated liposomes encapsulating doxorubicin and used U251MG-P1 cells as the target model in this study. The liposome modified with M-CTX-Fc was designed with a diameter of approximately 100–150 nm and showed high encapsulation efficiency, adequate loading capacity of anticancer drug, enhanced antitumor effects demonstrating increasing uptake into the cells in vitro; M-CTX-Fc-L-Dox shows great promise in its ability to suppress tumor growth in vivo and it could serve as a template for targeted delivery of other therapeutics.

[reaction: see text] A novel method for synthesizing 4-acetoxy-2-amino-3-arylbenzofurans (4) from 1-aryl-2-nitroethylenes (1) and cyclohexane-1,3-diones (2) is described. The method features one-pot operation of a solution of 1 and 2 in THF with catalytic Et3N (rt, 12 h) followed with Ac2O, Et3N, and DMAP (rt, 5 h), although the process consists of 13 elementary reactions.

No abstract

Cry4Aa toxin produced by Bacillus thuringiensis subsp. israelensis exhibits specific toxicity to larvae of medically-important mosquito genera. In the present study, we analyzed the characteristics of channel-pores formed by recombinant Cry4Aa in a solvent-free planar lipid bilayer. Stable channel-currents were observed in electrophysiologic measurements, and the single-channel conductance was 187 ± 10 pS in symmetrical buffer containing 150 mM KCl. The channel-pores formed by Cry4Aa were cation selective, with an estimated PK/PCl permeability ratio of 4.9. In addition, Cry4Aa channel-pores exhibited apparent cation preference in the order Na + > K + , Na + > Ca 2+ , and K + > Ca 2+ . Although the effect was limited, the cation preference of Cry4Aa channel-pores seemed to be correlated with toxicity. Culex pipiens mosquito larvae reared in NaCl solution exhibited greater sensitivity to Cry4Aa, particularly early period 2 after exposure. The presence of cations that preferentially translocate through Cry4Aa channel-pores may facilitate excessive influx of water into the midgut cells, leading to colloid-osmotic lysis. Whereas CaCl2 had some effect on the mosquito-larvicidal activity of Cry4Aa, KCl had no effect. The effect of some cations may be mitigated by the variety of ion channels present on the midgut cell membrane.

Channel-pore cation selectivity is a major determinant of Bacillus thuringiensis Cry46Ab mosquitocidal activity.