[Inhibitory effect of valproic acid on xenografted Kasumi-1 tumor growth in nude mouse and its mechanism].
OBJECTIVE
To investigate in vivo inhibitory effect of histone deacetylase (HDAC) inhibitor valproic acid (VPA) on xenografted Kasumi-1 tumor in nude mice and its mechanism.


METHODS
Xenografted Kasumi-1 tumor mouse model was established by subcutaneous inoculation of Kasumi-1 cells. Xenotransplanted nude mice were assigned into control or VPA treatment groups. Volume of the xenografted tumors was measured and compared between the two groups. Terminal deoxynucleotidyl transferase biotin-dUTP nick end labeling (TUNEL) was applied to detection of tumor cell apoptosis. The gene expression of GM-CSF, HDAC1, Ac-H3 and survivin was studied with semi-quantitative RT-PCR and Western blotting. ChIP method was used to assay the effects of VPA on acetylation of histone H3 within GM-CSF promoter region.


RESULTS
(1) VAP significantly inhibited xenografted Kasumi-1 tumor growth. The calculated inhibition rate was 57.25%. (2) Morphologic study showed that VPA induced differentiation and apoptosis of Kasumi-1 tumor cells. The apoptosis index of VAP treatment group [(3.661 +/- 0.768)%] was significantly higher than that of control group [(0.267 +/- 0.110)%]. (3) Comparing to those in control group, the level of nuclear HDAC1 protein was significantly decreased, the Ac-H3 protein expression level was increased, the mRNA and protein expression levels of GM-CSF and acetylation of histone H3 were remarkably increased, and the gene expression level of survivin significantly decreased in VPA treatment group.


CONCLUSIONS
VAP significantly inhibits xenografted Kasumi-1 tumor growth and induces tumor cell differentiation and apoptosis. The mechanism may be decrease of survivin gene expression, inhibition of nuclear expression of HDAC, promotion of histone protein acetylation level and acetylation of histone H3 within GM-CSF promoter region, and increase of GM-CSF transcription.
Department of Hematology, Affiliated Hospital of Chengde Medical College, Chengde 067000, China.
Peng
P
Liu
Xia
X
Tian
Gui-Rong
GR
Shi
Feng-Yun
FY
Jiang
Bao-Qin
BQ
Liu
Zhi-Hua
ZH
Zhang
Lei
L
Zhao
Li-Na
LN
Yan
Zhi-Qiang
ZQ
Liang
Chang-Lai
CL
Hao
D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D045744:Cell Line, Tumor; D056572:Histone Deacetylase Inhibitors / Q000494:pharmacology*; D006801:Humans; D051379:Mice; D008819:Mice, Nude; D014635:Valproic Acid / Q000494:pharmacology*; D023041:Xenograft Model Antitumor Assays
D056572:Histone Deacetylase Inhibitors; D014635:Valproic Acid