4742
We have shown that 1-(5-chloronaphthalene-1-sulfonyl)-1H-hexahydro-1,4-diazepine hydrochloride ( ML-9 ), an inhibitor of myosin light chain kinase , induces differentiation of monocytoid leukemia cell lines U937 and THP-1 but not of myeloblastic leukemic ML-1 cell or erythroleukemia K562 cells .
 U937, monocytoid leukemia cell lines, THP-1, myeloblastic leukemic ML-1 cell, erythroleukemia K562 cells, myosin light chain kinase
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:
 U937, monocytoid leukemia cell lines, THP-1, myeloblastic leukemic ML-1 cell, erythroleukemia K562 cells, myosin light chain kinase