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In human THP-1 monocytic leukemia cells cultured with RA (0.05 to 500 nmol/L), MCP-1 expression was induced rapidly, significantly, and dose-dependently by as much as 165-fold.
 human THP-1 monocytic leukemia cells, MCP-1
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: cell line, protein, RNA, DNA, cell type 
Text: {0} 
Answer:
 human THP-1 monocytic leukemia cells, MCP-1