14650
1,25-dihydroxy vitamin D3 and 12-O-tetradecanoyl phorbol-13-acetate ( TPA ) interact synergistically to induce monocytic differentiation of U937 histiocytic lymphoma cells .
 ( cell line: U937 histiocytic lymphoma cells, None) 
Locate the role in the text that participated in the event based on the event type and return it in the event list. 
 Option: Event type: RNA,cell type,protein,cell line,DNA, Arguments type: . 
Text: {0} 
Answer:
 ( cell line: U937 histiocytic lymphoma cells, None) 