The Expression of BTG2 and Its Regulatory Effect on Radiosensitivity of Lung Adenocarcinoma / 中国生物化学与分子生物学报

Among the types of lung cancer, lung adenocarcinoma accounts for the majority, and its overall survival rate is poor. B-cell translocation gene 2 (BTG2) is a member of the antiproliferative gene family, belonging to the BTG/TOB family. Many studies have shown that BTG2 was abnormally expressed in many types of tumors, but its regulatory role in the radiosensitivity of lung adenocarcinoma remained unclear. In this study, we explored the expression level of BTG2 in patients with lung adenocarcinoma and its correlation with clinical prognosis through online database and tissue samples of lung adenocarcinoma patient. The results indicated that the expression level of BTG2 decreased significantly in lung adenocarcinoma patient with radiation resistance. Bioinformatics analysis confirmed that BTG2 could respond to radiotherapy in lung adenocarcinoma cell lines, and its low expression in lung adenocarcinoma patients was associated with poor prognosis (P < 0.05). The lentivirus overexpressing BTG2 (OE-BTG2) was transfected into human lung adenocarcinoma cell lines to increase the expression level of BTG2 including A549 and H1299. And the effect of BTG2 overexpression on the radiosensitivity of lung adenocarcinoma cell lines was detected by clone formation assay. Clone formation experiment confirmed that overexpression of BTG2 could significantly enhance the radiosensitivity of A549 and H1299 cell lines (P < 0.05). The expression levels of BTG2 and apoptosis related protein-Bax were detected by Western blotting (WB) and immunohistochemistry (IHC). The effect of BTG2 on radiation sensitivity of lung adenocarcinoma was further detected via nude mouse in vivo. WB experiment confirmed that BTG2 upregulation could significantly increase the apoptosis level of A549 and H1299 cells after radiation. Moreover, BTG2 overexpression can markedly enhance the radiosensitivity of lung adenocarcinoma (P < 0.05) and increase the protein level of Bax after radiation in vivo. In conclusion, BTG2 had low expression in lung adenocarcinoma patients and its low expression level was closely related to the poor clinical prognosis. Overexpression of BTG2 can increase the radiosensitivity of lung adenocarcinoma cell lines and promote the process of apoptosis after radiation, indicating a new target for overcoming the radiation resistance of lung adenocarcinoma.

Effect of valproic acid against angiogenesis of Kasumi-1 xenograft tumor in nude mice / 中国实验血液学杂志

This study was aimed to investigate the effect of valproic acid (VPA), a histone deacetylase inhibitor, on angiogenesis of acute myeloid leukemia in vivo and vitro, and to explore its molecular mechanism. Human t (8;21) AML cell line Kasumi-1 cells were treated with VPA at different concentration for 3 d, the mRNA and protein expression levels of Ang1 and Ang2 were determined by semi-quantitative RT-PCR and Western blot respectively. Nude mice model with xenograft Kasumi-1 tumor was established by subcutaneous inoculation of Kasumi-1 cells. The CD34, Ang1 and Ang2 protein levels were analyzed by immunohistochemistry method. The mRNA and protein expression levels of Ang1, Ang2 and VEGF were determined by semi-quantitative RT-PCR and Western blot. The results showed that in vitro, VPA at 3 mmol/L downregulated the Ang mRNA relative expression level for Ang1 from 0.360 ± 0.116 to 0.040 ± 0.008, Ang2 from 0.540 ± 0.049 to 0.146 ± 0.038. The animal experiment further verified that VPA 500 mg/kg, ip, for 14 d, reduced the relative expression of Ang1, Ang2 and VEGF mRNA and proteins in Kasumi-1 tumor of nude mice, and reduced microvascular density in xenograft tumor of nude mice (8.470 ± 0.300 vs 2.600 ± 0.200). It is concluded that VPA significantly inhibits tumor angiogenesis through the regulation of angiopoietins, thereby inhibits the proliferation and metastasis of leukemia cells.

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>

Reversed effect of valproic acid on transcription inhibition of AML1-ETO fusion protein of kasumi-1 leukemic cell line / 中国实验血液学杂志

This study was aimed to investigate the mechanism of histone deacetylase (HDAC) inhibitor, valproic acid (VPA), reversing transcription inhibition of AML1-ETO fusion protein in Kasumi-1 cell line. The mRNA expressions of AML1-ETO, AML1 and cyclin D2 were detected by semi-quantitation RT-PCR after treating kasumi-1 cells with VPA at different doses/and different time points. The results indicated that the mRNA expression of AML1-ETO showed no obvious change, when kasumi-1 cells were treated with VPA. Compared with control group, the expression level of AML1 mRNA significantly increased in a dose-dependent manner. Compared with control group, the expression level of cyclin D2 mRNA significantly decreased when kasumi-1 cells had been treated with 3 mmol/L VPA as well as kasumi-1 cells were treated with different concentrations of VPA for 3 days. In conclusion, VPA could remove transcription inhibition of AML1-ETO fusion protein, increase transcription of AML1 and down-regulate mRNA expression of AML1 target gene cyclin D2 through HDAC inhibiting activity.

Inhibitory effect of valproic acid on cell cycle of Kasumi-1 cell line and its mechanism / 中华血液学杂志

<p><b>OBJECTIVE</b>To investigate the influence of valproic acid (VPA), a histone deacetylase (HDAC) inhibitor, on cell cycle of Kasumi-1 cells, and explore its molecular mechanism.</p><p><b>METHODS</b>Kasumi-1 cells were treated with VPA at different concentration and different time cell cycle changes were analyzed by flow cytometry. Cyclin D1 and p21(WAF1/CIP) gene, a cyclin-dependent kinase inhibitor, were determined by semi-quantitative RT-PCR and Western blot.</p><p><b>RESULTS</b>(1) VPA blocked the Kasumi-1 cells in G(0)/G(1) phase. (2) Compared with control group, 3 mmol/L VPA treated Kasumi-1 cells for different times caused their mRNA expression of cyclin D1 decreased. Treated with VPA at different concentration for 3 days, the mRNA expression decreased in a dose-dependent manner. (3) VPA induced p21(WAF1/CIP) mRNA expression increased in a time- and dose-dependent manner. The p21(WAF1/CIP) protein increased with increasing concentration of VPA at day 3. The p21(WAF1/CIP) protein significantly increased with 3 mmol/L VPA treatment for 2 d (2.498 +/- 0.240).</p><p><b>CONCLUSION</b>VPA can arrest Kasumi-1 cell in G(0)/G(1) phase through the regulation of cyclin D1 and p21(WAF1/CIP).</p>