10228
In a previous study, we demonstrated that bufalin , which is an active principle of Chinese medicine , chan'su , caused apoptosis in human leukemia U937 cells by anomalous activation of mitogen-activated protein kinase ( MAPK ) via the signaling pathway of Ras , Raf-1 , and MAPK kinase-1 .
 ( protein: Raf-1, None) , ( cell line: human leukemia U937 cells, None) , ( protein: MAPK, None) , ( protein: MAPK kinase-1, None) , ( protein: Ras, None) , ( protein: MAPK, None) , ( protein: mitogen-activated protein kinase, 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:
 ( protein: Raf-1, None) , ( cell line: human leukemia U937 cells, None) , ( protein: MAPK, None) , ( protein: MAPK kinase-1, None) , ( protein: Ras, None) , ( protein: MAPK, None) , ( protein: mitogen-activated protein kinase, None) 