Lithocholic acid-based oligomers as drug delivery candidates targeting model of lipid raft.

This study presents a new approach to designing a lithocholic acid functionalized oligomer (OLithocholicAA-X) that can be used as a drug carrier with additional, beneficial activity. Namely, this novel oligomer can incorporate an anti-cancer drug due to the application of an effective backbone as its component (lithocholic acid) alone is known to have anticancer activity. The oligomer was synthesized and characterized in detail by nuclear magnetic resonance, attenuated total reflectance Fourier-transform infrared spectroscopy, ultraviolet-visible spectroscopy, thermal analysis, and mass spectrometry analysis. We selected lipid rafts as potential drug carrier-membrane binding sites. In this respect, we investigated the effects of OLithocholicAA-X on model lipid raft of normal and altered composition, containing an increased amount of cholesterol (Chol) or sphingomyelin (SM), using Langmuir monolayers and liposomes. The surface topography of the studied monolayers was additionally investigated by atomic force microscopy (AFM). The obtained results showed that the investigated oligomer has affinity for a system that mimics a normal lipid raft (SM:Chol 2:1). On the other hand, for systems with an excess of SM or Chol, thermodynamically unfavorable fluidization of the films occurs. Moreover, AFM topographies showed that the amount of SM determines the bioavailability of the oligomer, causing fragmentation of its lattice.

Changes in cellular response to the damage induced in PC-3 prostate cancer cells by proton microbeam irradiation.

The aim of this research was to find out whether the passage number effect may influence on the PC-3 cells (the human prostate cancer line derived from bone metastases) response to proton radiation. 2 MeV horizontally focused proton microbeam was used as a radiation source. The cells were treated with a counted number of H(+) ions (50-8000) corresponding to doses of 1.3-209 Gy/cell. For comparison, cell death was also induced by UVC radiation. All cells were stained with Hoechst 33342 and propidium iodide and visualized under a fluorescence microscope. Necrosis was observed at: a) 8000 protons per cell (corresponding to ∼209 Gy/cell) after 2-4 passages, b) 3200 protons per cell (corresponding to ∼84 Gy/cell) for cells after 11-14 passages and c) only 800 protons per cell (corresponding to ∼2 Gy/cell ) after 47-50 passages. Apoptosis was efficiently induced, by protons, only in cells after 50 passages. The results showed that the laboratory conditions affected cellular response of PC-3 cell line to the proton irradiation. The cellular response to the radiation treatment strongly depends on number of passages.