You will be shown an abstract from a biomedical research paper. Given this abstract, your task is to extract all unique entities of the following types: ["Chemical"].

Please return the output as a JSON object of the format: {"Chemical": ["Arsenic", ...]}. The keys should be entity types and values should be lists of extracted entities belonging to the corresponding type. If you cannot find entities belonging to a specific type, the value should be [].

Only output the JSON object and do not include any additional text.

Abstract:

Azaspiracid-1 inhibits the maturation of cathepsin D in mammalian cells. Azaspiracid-1 (AZA-1) inhibits endocytosis, but the consequences of this alteration on cellular processes are unknown. We hypothesized that the inhibition of endocytosis is a key step of the mode of action of AZA-1, leading to perturbation of cellular processes dependent on proper functioning of endocytic machinery. We tested this working hypothesis by probing whether AZA-1 can alter the maturation of cathepsin D in MCF-7 epithelial cells, as a model system. We found that cell treatment with AZA-1 inhibited the conversion of 52 kDa procathepsin D into the mature 30 kDa protein. The effects induced by AZA-1 were similar to those elicited by chlorpromazine and other agents preventing proper maturation of lysosomal enzymes, indicating that the inhibition of endocytic transfer of proforms to late endosomes/lysosomess is responsible for the effect induced by the toxin. By immunofluorescence microscopy, we found no colocalization of cathepsin D and the early endosomal marker EEA-1 in control cells, where most of cathepsin D resides in late endosomes/lysosomes. Co-localization of cathepsin D and EEA-1 immunoreactivity, in turn, was found in cells exposed to AZA-1, indicating that the toxin blocks protein maturation at the early steps of endocytosis, causing accumulation of procathepsin D in early endosomes. The molecular alteration induced by AZA-1 involved both secreted and intracellular pools of procathepsin D, showing that the toxin effect does not result from a general impairment of vesicular trafficking but is the outcome of a perturbed centripetal process. Furthermore, AZA-1 was found to inhibit procathepsin D maturation also in normal fibroblasts, showing that this molecular response is induced by this toxin in different cell types. The data we obtained corroborated our hypothesis and provide a unified molecular frame for the mode of action of AZAs in animal models, involving a primary alteration of endocytic processes.
{"Chemical": ["Azaspiracid-1", "AZAs", "AZA-1", "chlorpromazine"]}