Inhibitory effect of valproic acid on xenografted Kasumi-1 tumor growth in nude mouse and its mechanism / 中华血液学杂志

<p><b>OBJECTIVE</b>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.</p><p><b>METHODS</b>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.</p><p><b>RESULTS</b>(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.</p><p><b>CONCLUSION</b>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.</p>

Effects of histone deacetylase inhibitor on the expression of angiogenesis related factors in Kasumi-1 leukemic cell line / 中华血液学杂志

<p><b>OBJECTIVE</b>To investigate the effects of two histone deacetylase (HDAC) inhibitors, valproic acid (VPA) and TSA, on the expression of vascular endothelial growth factor (VEGF) and its receptor KDR of the leukemia cell line Kasumi-1 cells, and to explore their potential mechanism in leukemia angiogenesis.</p><p><b>METHOD</b>Kasumi-1 cells were treated with VPA and TSA at different concentrations for 3 days. The mRNA and protein expression levels of VEGF and KDR were determined by semi-quantitative RT-PCR and Western blot, and the bFGF mRNA by semi-quantitative RT-PCR.</p><p><b>RESULTS</b>As compared with that of control groups, VPA at 3 mmol/L downregulated the VEGF mRNA expression level for VEGF(121) from 0.632 ± 0.014 to 0.034 ± 0.004 and for VEGF(165) from 0.526 ± 0.021 to 0.015 ± 0.001, for KDR mRNA from 0.258 ± 0.034 to 0.038 ± 0.000, and for bFGF mRNA from 0.228 ± 0.017 to 0.086 ± 0.015. TSA downregulated the VEGF mRNA and KDR mRNA at concentration of 100 nmol/L, but its effect on bFGF mRNA only at higher concentration.</p><p><b>CONCLUSION</b>HDAC inhibitors might inhibit the leukemia angiogenesis by regulating the expression of VEGF and its recptor.</p>