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:

Detection of Statin Cytotoxicity Is Increased in Cells Expressing the OATP1B1 Transporter. Cytotoxicity of a compound is determined by the intracellular concentration mediated both by passive permeability and active uptake through drug transporters. However, the major liver uptake transporters were either absent or expressed at significantly lower levels in human liver cell lines than in human liver. When comparing cytotoxicity of five statins, the organic anion transporting polypeptide 1B1 (OATP1B1) expressing HEK cells showed a significantly higher sensitivity than the wild-type HEK cells. The IC50 shifts ranged from 9- to >100-fold, and the potency shifts collapsed in the presence of rifampicin, the inhibitor for OATPs. The extent of the IC50 shift correlated with the permeability of the statins with high permeable compounds having smaller shifts and low permeable compounds having larger shifts. The changes in statin potency in transporter transfected cells reflect the active uptake of statins into the cells and the increased intracellular drug concentration lead to increased toxicity. The data suggested that uptake transporters have a significant impact on the outcomes of a cell-based assay and should be considered during the early stages of compound toxicity screening in drug discovery. For compounds with low permeability which are likely to undergo transporter-mediated uptake, it is important to test them in transporter-competent cell models.
{"Chemical": ["rifampicin"]}