Nm23-H1 regulates the proliferation and differentiation of the human chronic myeloid leukemia K562 cell line: a functional proteomics study.
OBJECTIVE
Nm23-H1 is a suppressor of metastasis that has been implicated in the regulation of proliferation and differentiation of hematopoietic cells, although specific mechanisms for Nm23-H1 have not been well-characterized. Our study is designed to further elucidate the role of Nm23-H1 in the human chronic myeloid leukemia K562 cell line.


METHODS
In this study we generated and selected two cell clone pools of human chronic myeloid leukemia K562 cells with up-regulated and down-regulated Nm23-H1 expression.


RESULTS
Our data show that knockdown of Nm23-H1 decreased proliferation and increased the percentage of cells arrested in the G0/G1 phase of the cell cycle. Correspondingly, K562 cells overexpressing Nm23-H1 were more proliferative. After treatment of these two cell types with phorbol 12-myristate 13-acetate (PMA) for 48 h, cells with reduced Nm23-H1 expression had a higher percentage of 8N ploidy and higher expression of CD41 than K562 cells overexpressing Nm23-H1. A functional proteomics analysis identified ten proteins, including ANP32A, Cdc42GAP, and the isoform 2 of SET, whose expression levels were significantly altered by down-regulation of Nm23-H1. In addition, cells with decreased levels of Nm23-H1 had significantly reduced expression of Cdc42 independent of treatment with PMA. The interaction of the endogenous Nm23-H1 and Cdc42 proteins has been further validated by reciprocal immunoprecipitations.


CONCLUSIONS
We provide data that complement functional studies of Nm23-H1 in regulating hematopoietic cells, and address action mechanisms of Nm23-H1 that have not previously been reported.
Jin
Lin
L
The Institute of Pharmacology Science, Jinan University, Guangzhou, 510632 China.
Liu
Ge
G
Zhang
Chuan-hai
CH
Lu
Chun-hua
CH
Xiong
Sheng
S
Zhang
Mei-ying
MY
Liu
Qiu-Ying
QY
Ge
Feng
F
He
Qing-Yu
QY
Kitazato
Kaio
K
Kobayashi
Nobuyuki
N
Wang
Yi-Fei
YF
D002454:Cell Differentiation / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D015536:Down-Regulation; D006801:Humans; D020014:K562 Cells; D054778:NM23 Nucleoside Diphosphate Kinases / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D040201:Platelet Membrane Glycoprotein IIb / Q000096:biosynthesis; D040901:Proteomics / Q000379:methods; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014162:Transfection; D015854:Up-Regulation; D020764:cdc42 GTP-Binding Protein / Q000096:biosynthesis
D054778:NM23 Nucleoside Diphosphate Kinases; D040201:Platelet Membrane Glycoprotein IIb; D020764:cdc42 GTP-Binding Protein; D013755:Tetradecanoylphorbol Acetate