ABSTRACT
Background Arsenic is a toxicant that can affect the expressions of the cellular anti-apoptotic gene BCL-2 and its protein, but the effects of arsenic on BCL-2α and BCL-2\begin{document}$\beta $\end{document} transcripts have not been reported. Objective To investigate the potential effects of arsenic and its metabolites, methylarsonic acid (MMA) and dimethylarsonic acid (DMA), on BCL-2α, BCL-2\begin{document}$\beta $\end{document}, and BCL-2T (total of α and \begin{document}$\beta $\end{document} transcripts) in human bronchial epithelial cells (16HBE) and human lung adenocarcinoma cells (A549). Methods 16HBE cells and A549 cells were randomly divided into three categories of exposure after in vitro culture: single-selected arsenic compound exposure groups with isoconcentration (16HBE cells were treated with 4.5 μmol·L−1 of MMA, DMA, and sodium arsenite, respectively, while A549 cells were treated with 60 μmol·L−1 of MMA, DMA, and sodium arsenite, respectively), sodium arsenite exposure groups with different concentrations (16HBE cells were treated with 1.5, 3.0, and 4.5 μmol·L−1 of sodium arsenite respectively, while A549 cells were treated with 20, 40, and 60 μmol·L−1 of sodium arsenite respectively), and combined exposure groups (i.e. MMA+sodium arsenite, and DMA+sodium arsenite; the exposure concentrations of 16HBE cells were both 1.5 μmol·L−1 and both 4.5 μmol·L−1 respectively, and those of A549 cells were both 20 μmol·L−1 and both 60 μmol·L−1 respectively). Meanwhile, a blank control group was also set up in each exposure category. After 48 h of continuous exposure, the relative expressions of BCL-2α, BCL-2\begin{document}$\beta $\end{document}, and BCL-2T in both cells were detected by real-time PCR. Results Regarding the single-selected arsenic compound exposure, in 16HBE cells, the expression levels of BCL-2α and BCL-2T under 4.5 μmol·L−1 MMA treatment were lower than those in their control groups (q=3.27, 2.93, both P<0.05), and the expression levels of BCL-2α, BCL-2\begin{document}$\beta $\end{document}, and BCL-2T under 4.5 μmol·L−1 sodium arsenite were lower than those in their respective control groups (q=11.06, 3.65, 10.70, all P<0.05). In A549 cells, the expression level of BCL-2T treated with 60 μmol·L−1 DMA was lower than that in the control group (q=3.12, P<0.05), and the expression levels of BCL-2α, BCL-2\begin{document}$\beta $\end{document}, and BCL-2T treated with 60 μmol·L−1 sodium arsenite were lower than those in their respective control groups (q=7.59, 7.27, 8.06, all P<0.05). Regarding the sodium arsenite exposure: 16HBE cells treated with 1.5 μmol·L−1 sodium arsenite had a lower expression level of BCL-2α and a higher expression level of BCL-2\begin{document}$\beta $\end{document} than those in their respective control groups (q=6.06, 11.92, both P<0.05); the expression level of BCL-2α under 3.0 μmol·L−1 sodium arsenite was lower than that in the control group (q=12.72, P<0.05); and under 4.5 μmol·L−1 sodium arsenite treatment, the expression levels of BCL-2α, BCL-2\begin{document}$\beta $\end{document}, and BCL-2T were lower than those in their respective control groups (q=15.72, 6.79, 6.62, all P<0.05). The expression levels of BCL-2α gradually decreased with increasing concentrations of sodium arsenite (Fα trend=144.80, P<0.001), while BCL-2\begin{document}$\beta $\end{document} and BCL-2T decreased in a dose-dependent manner in the range of 1.5-4.5 μmol·L−1 (F\begin{document}${}_{\beta } $\end{document} trend=135.40, FT trend=38.24, both P<0.001). In A549 cells, the expression levels of BCL-2α, BCL-2\begin{document}$\beta $\end{document}, and BCL-2T under each concentration of sodium arsenite treatments were lower than those in their respective control groups (all P<0.05); the results of further trend tests showed that their expression levels gradually decreased with increasing concentrations of sodium arsenite (Fα trend =31.97, F\begin{document}${}_{\beta} $\end{document} trend=549.50, FT trend=252.40, all P<0.001). Regarding the combined exposure, under MMA+sodium arsenite treatment at both 60 μmol·L−1, the expression levels of BCL-2α, BCL-2\begin{document}$\beta $\end{document}, and BCL-2T in A549 cells were higher than those in their respective control groups (q=6.37, 14.91, 5.33, all P<0.05); under DMA+sodium arsenite treatment at both 60 μmol·L−1, their expression levels in A549 cells were also higher than those in their respective control group (q=8.60, 17.29, 6.91, all P<0.05). Conclusion Exposure to a high concentration (16HBE: 4.5 μmol·L−1, A549: 60 μmol·L−1) of a single arsenic metabolite has no effect on BCL-2 transcripts in 16HBE cells and A549 cells. Exposure to a low concentration (1.5 μmol·L−1) of sodium arsenite alone would decrease the expression level of BCL-2α and increase the expression level of BCL-2\begin{document}$\beta $\end{document} in 16HBE cells, and exposure to all designed concentrations of sodium arsenite alone would decrease the expressions of all transcripts in A549 cells. The combined exposure to high concentrations (both 60 μmol·L−1) of MMA plus sodium arsenite or high concentrations (both 60 μmol·L−1) of DMA plus sodium arsenite would increase the expressions of BCL-2α, BCL-2\begin{document}$\beta $\end{document}, and BCL-2T in A549 cells, which are different from the effects presented by single exposure.
ABSTRACT
Objective:To explore the mechanism of a novel BMX splicing variant induced epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) gefitinib resistance in lung cancer.Methods:Stable transgenic cell line PC9-BMXΔN and HCC827-BMXΔN were constructed by lentivirus infection of PC9 and HCC827 cells carrying EGFR mutation. The cells were divided into PC9-Vec group (PC9 cells transfected with empty vector), PC9-BMX group (PC9 cells stably expressing BMX), PC9-BMXΔN group (PC9 cells stably expressing BMXΔN) and HCC827-Vec group (HCC827 cells transfected with empty vector), HCC827-BMXΔN group (HCC827 cells stably expressing BMXΔN). Quantitative real-time PCR was used to detect the expression levels of mRNA. The protein expression levels in each group were detected by Western blotting. The cells in the PC9-Vec group and PC9-BMXΔN group were treated with 0, 0.01, 2.00, 50.00, 100.00, 200.00 nmol/L and 2.00, 4.00 μmol/L gefitinib. The cells in the HCC827-Vec group and HCC827-BMXΔN group were treated with 0, 0.01, 1.00, 10.00, 100.00 nmol/L and 1.00 μmol/L gefitinib. MTT method was used to detect cell viabilities.Results:The PC9-BMXΔN cells were scattered and showed a fibroblast-like morphology. Compared with the PC9-Vec cells, the relative expression levels of fibronectin, N-cadherin, vimentin, Snail, Slug and TWIST 2 mRNA in PC9-BMXΔN cells were up-regulated. Compared with the PC9-Vec cells and PC9-BMX cells, the expression levels of fibronectin and vimentin protein in PC9-BMXΔN cells were up-regulated; while the expression level of E-cadherin protein in PC9-BMXΔN cells was significantly down-regulated. Compared with the PC9-Vec cells, the cell viabilities of PC9-BMXΔN cells treated with 0.01 nmol/L [(99.11±2.16)% vs. (91.29±1.91)%, t=-4.701, P=0.011], 2.00 nmol/L [(80.41±1.48)% vs. (63.36±2.14)%, t=-11.324, P<0.001], 50.00 nmol/L [(80.83±5.38)% vs. (60.22±3.61)%, t=-5.507, P=0.005], 100.00 nmol/L [(75.54±3.46)% vs. (59.93±1.91)%, t=-6.836, P=0.002], 200.00 nmol/L [(77.57±6.53)% vs. (56.70±2.88)%, t=-5.064, P=0.007], 2.00 μmol/L [(70.22±3.45)% vs. (53.14±0.89)%, t=-8.309, P=0.001], 4.00 μmol/L [(68.66±4.67)% vs. (52.30±2.59)%, t=-4.882, P=0.008] gefitinib were significantly increased, with statistically significant differences. Similarly, compared with the HCC827-Vec cells, the cell viabilities of HCC827-BMXΔN cells treated with 1.00 nmol/L [(64.36±2.49 )% vs. (47.13±4.21)%, t=-7.067, P=0.019], 10.00 nmol/L [(63.25±5.87)% vs. (43.28±2.95)%, t=-5.267, P=0.006], 100.00 nmol/L [(49.47±5.74)% vs. (37.12±4.92)%, t=-2.830, P=0.047], 1.00 μmol/L [(49.05±3.34)% vs. (32.06±4.73)%, t=-5.073, P=0.007] gefitinib were significantly increased, with statistically significant differences. Gefitinib treatment could significantly inhibit the expression levels of p-EGFR and p-ERK1/2 both in PC9-Vec cells, PC9-BMX cells and PC9-BMXΔN cells. Compared with the PC9-Vec cells and PC9-BMX cells, the expression level of p-EGFR in PC9-BMXΔN cells was significantly increased after gefitinib treatment for 8 h (0.91±0.04 vs. 0.81±0.04 vs. 0.80±0.05, all P<0.05); the expression levels of p-ERK1/2 in PC9-BMXΔN cells were significantly increased after gefitinib treatment for 2 h (0.64±0.06 vs. 0.38±0.12 vs. 0.37±0.14), 4 h (1.28±0.06 vs. 1.08±0.06 vs. 1.11±0.07), and 8 h (0.75±0.04 vs. 0.55±0.05 vs. 0.60±0.07), with statistically significant differences (all P<0.05). Conclusion:BMXΔN is involved in EGFR-TKI gefitinib resistance in lung cancer, which may be achieved by inducing cells to undergo epithelial-mesenchymal transition and activating the ERK/MAPK signaling pathway.
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Objective To study the anti-depression mechanism of Dingzhixiaowan concerning on histology of hippocampal formation.Methods 40 female rats were divided into control,depression model group(model group),distilled water group(DW group) and Dingzhixiaowan group(Chinese herb group).Behavior points were measured by open field method.Serum concentrations of cortisol and estradiol(E2) were checked with ELISA.HE staining and electron microscopy were applied to observe the histology of neurons in hippocampal formation.Immunohistochemistry method was employed to detect Nestin expression.Results Compared with the control,behavior points,serum E2 level and Nestin expression decreased obviously and serum cortisol level increased markedly,CA3 neurons were seriously damaged in model and DW groups.While behavior points,serum E2 level did not change,Nestin expression increased obviously and serum cortisol level decreased markedly,CA3 neurons were basically normal in Chinese herb groups.Conclusion Dingzhixiaowan can protect hippocampal formation,which might be one of the anti-depression mechnisms.
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Objective To study the expression and significance of neuronal nitric oxide synthase(nNOS) in ureteropelvic junction obstruction(UPJO).Methods Specimens of the narrow segment of the ureteropelvic junction(UPJ) were obtained from 36 cases of UPJO(without aberrant vessels,adhesive band compression and high insertion of ureteral junction).Furthermore,the light microscopic examination demonstrated that smooth muscle fascicles were sparse and thin,and fibrous connective tissues between them were deposited.Control UPJ specimens were taken from 20 cases of renal neoplasm,and tissues were confirmed histologically to be unaffected.Immunohistochemical staining(SABC method) was performed to detect the expression of nNOS in specimens of the 2 groups.Quantitative analysis was made using image analysis technique. Results Immunoreactivity to nNOS was predominantly present in the smooth muscle cell cytoplasm of UPJ.The mean density of nNOS in UPJO and control groups was 0.208?0.014 and 0.230?(0.016),respectively,which were significantly different between the 2 groups(P