000K utf8 1100 $c2021 1500 eng 2050 urn:nbn:de:gbv:8:3-2022-00221-8 2051 10.3390/ijms22083864 3000 Heneweer, Carola 3010 Kalthoff, Holger 3010 Kolesnick, Richard 3010 Larson, Steven 3010 Peñate Medina, Oula Antti Rafael 3010 Peñate Medina, Tuula 3010 Tower, Robert 4000 Acid-Sphingomyelinase Triggered Fluorescently Labeled Sphingomyelin Containing Liposomes in Tumor Diagnosis after Radiation-Induced Stress [Heneweer, Carola] 4209 In liposomal delivery, a big question is how to release the loaded material into the correct place. Here, we will test the targeting and release abilities of our sphingomyelin-consisting liposome. A change in release parameters can be observed when sphingomyelin-containing liposome is treated with sphingomyelinase enzyme. Sphingomyelinase is known to be endogenously released from the different cells in stress situations. We assume the effective enzyme treatment will weaken the liposome making it also leakier. To test the release abilities of the SM-liposome, we developed several fluorescence-based experiments. In in vitro studies, we used molecular quenching to study the sphingomyelinase enzyme-based release from the liposomes. We could show that the enzyme treatment releases loaded fluorescent markers from sphingomyelin-containing liposomes. Moreover, the release correlated with used enzymatic activities. We studied whether the stress-related enzyme expression is increased if the cells are treated with radiation as a stress inducer. It appeared that the radiation caused increased enzymatic activity. We studied our liposomes' biodistribution in the animal tumor model when the tumor was under radiation stress. Increased targeting of the fluorescent marker loaded to our liposomes could be found on the site of cancer. The liposomal targeting in vivo could be improved by radiation. Based on our studies, we propose sphingomyelin-containing liposomes can be used as a controlled release system sensitive to cell stress. 4950 https://doi.org/10.3390/ijms22083864$xR$3Volltext$534 4950 https://nbn-resolving.org/urn:nbn:de:gbv:8:3-2022-00221-8$xR$3Volltext$534 4961 https://macau.uni-kiel.de/receive/macau_mods_00002624 5051 610 5550 Animals 5550 Catalysis 5550 Cell Line, Tumor 5550 Cell Stress 5550 Controlled release 5550 Disease Models, Animal 5550 Drug Delivery 5550 Enzyme Activation 5550 Fluorescence 5550 Fluorescent Dyes 5550 Liposome 5550 Liposomes 5550 Mice 5550 Molecular Imaging 5550 Neoplasms 5550 Optical Imaging 5550 Quenching 5550 Sphingomyelinase 5550 Sphingomyelin Phosphodiesterase 5550 Sphingomyelins 5550 Staining and Labeling 5550 Stress, Physiological