Objective: To study on the effective molecular mechanism of Indigo Naturalis in intervening K562 cell of chronic myelocytic leukemia(CML) under the guidance of protein-protein interaction network

the molecular docking technique and in vitro cell experiment. Method: CML-related genes were obtained by screening the online mendelian inheritance in man database(OMIM)

then String 10.0 was used for text mining and constructing the CML protein-protein interaction network

the interaction data were input in Cytoscape 3.4.0 software and plug-in CentiScaPe 2.1 was used to implement topology analysis.Small active substances of Indigo Naturalis were obtained from a third-party database

which were optimized by Chemoffice 8.0 and Sybyl 8.1

then small molecular ligand library was obtained the molecular docking was carried out by Surflex-Dock module and the target

the key target was received after scoring.After in vitro experiment was designed

MTT assay was used to detect the inhibition rate of proliferation of K562 cell in blank group(drug-free serum) and experimental group(10%

20% and 30% serum contained Indigo Naturalis) at 24

48

72 h

while the expression of JAK2 protein was detected by Western blot. Result: Protein-protein interaction network of CML was constructed

which consisting of 425 nodes (proteins) and 2 799 sides (interactions)

the key gene JAK2 was got by further analyzed.Indigo Naturalis can inhibit the proliferation of K562 cell and reduce the expression of JAK2 protein. Conclusion: CML is a complex disease controlled by polygene

JAK2 is likely to be a key node

the mechanism underlying the inhibitory effect of Indigo Naturalis on the proliferation of K562 cell may relate to the down-regulation of JAK2 protein by indirubin.