Transethnic analysis of the human leukocyte antigen region for ulcerative colitis reveals not only shared but also ethnicity-specific disease associations

Inflammatory bowel disease (IBD) is a chronic inflammatory disease of the gut. Genetic association studies have identified the highly variable human leukocyte antigen (HLA) region as the strongest susceptibility locus for IBD, and specifically DRB1*01:03 as a determining factor for ulcerative colitis (UC). However, for most of the association signal such a delineation could not be made due to tight structures of linkage disequilibrium within the HLA. The aim of this study was therefore to further characterize the HLA signal using a trans-ethnic approach. We performed a comprehensive fine mapping of single HLA alleles in UC in a cohort of 9,272 individuals with African American, East Asian, Puerto Rican, Indian and Iranian descent and 40,691 previously analyzed Caucasians, additionally analyzing whole HLA haplotypes. We computationally characterized the binding of associated HLA alleles to human self-peptides and analysed the physico-chemical properties of the HLA proteins and predicted self-peptidomes. Highlighting alleles of the HLA-DRB1*15 group and their correlated HLA-DQ-DR haplotypes, we identified consistent associations across different ethnicities but also identified population-specific signals. We observed that DRB1*01:03 is mostly present in individuals of Western European descent and hardly present in non-Caucasian individuals. We found peptides predicted to bind to risk HLA alleles to be rich in positively charged amino acids such. We conclude that the HLA plays an important role for UC susceptibility across different ethnicities. This research further implicates specific features of peptides that are predicted to bind risk and protective HLA proteins

Исследование фотодинамического действия блеббистатина на раковые клетки человека

Фотосинтез и фотобиологи

Quantum dots affect expression of CD133 surface antigen in melanoma cells

Simona Steponkiene1-3, Simona Kavaliauskiene1, Rasa Purviniene4, Ricardas Rotomskis3,5, Petras Juzenas11Department of Radiation Biology, Institute for Cancer Research, Oslo University Hospital, Radiumhospital, Oslo, Norway; 2Faculty of Natural Sciences, Vilnius University, Vilnius, Lithuania; 3Biomedical Physics Laboratory of Oncology Institute, Vilnius University, Vilnius, Lithuania; 4Immunology Laboratory of Oncology Institute, Vilnius University, Vilnius, Lithuania; 5Biophotonics Laboratory, Laser Research Center, Vilnius University, Vilnius, LithuaniaBackground: In novel treatment approaches, therapeutics should be designed to target cancer stem cells (CSCs). Quantum dots (QDs) are a promising new tool in fighting against cancer. However, little is known about accumulation and cytotoxicity of QDs in CSCs.Methods: Accumulation and cytotoxicity of CdTe-MPA (mercaptopropionic acid) QDs in CSCs were assessed using flow cytometry and fluorescence-activated cell sorting techniques as well as a colorimetric cell viability assay.Results: We investigated the expression of two cell surface-associated glycoproteins, CD44 and CD133, in four different cancer cell lines (glioblastoma, melanoma, pancreatic, and prostate adenocarcinoma). Only the melanoma cells were positive to both markers of CD44 and CD133, whereas the other cells were only CD44-positive. The QDs accumulated to a similar extent in all subpopulations of the melanoma cells. The phenotypical response after QD treatment was compared with the response after ionizing radiation treatment. The percentage of the CD44high-CD133high subpopulation decreased from 72% to 55%–58% for both treatments. The stem-like subpopulation CD44highCD133low/- increased from 26%–28% in the untreated melanoma cells to 36%–40% for both treatments.Conclusion: Treatment of melanoma cells with QDs results in an increase of stem-like cell subpopulations. The changes in phenotype distribution of the melanoma cells after the treatment with QDs are comparable with the changes after ionizing radiation.Keywords: prominin-1, CD44, glycoproteins, flow cytometry, FACS, nanoparticle

Carbon-core silver-shell nanodots as sensitizers for phototherapy and radiotherapy

Spherical carbon nanoparticles (carbon nanodots) with a silver shell were investigated as potential sensitizing agents. The cytotoxicity of the combination of ultraviolet radiation or x-rays with the nanodots was examined in cancer cells in vitro. The cell viability decreased following the exposure to the radiation. The carbon nanodots enhanced the radiation effects by significantly reducing the amount of surviving cells compared to that of the cells exposed only to the radiation. Carbon-core silver-shell nanodots can be proposed as a bimodal sensitization platform for biological and medicinal applications employing non-ionizing or ionizing radiation