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Objective To investigate the effect of L-carnitine (LCNT) combined with epirubicin (EPI) on cell proliferation and apoptosis of two lung adenocarcinoma cell lines (GLC-82 and A549). Methods GLC-82 and A549 cells were divided into control group, EPI group, LCNT group and EPI+LCNT group, respectively. The cell proliferation rate was examined by MTT assay 24 h after the treatment, and the cell cycle and cell early apoptosis were analyzed by flow cytometry. The expression of P53 and Bcl-2 proteins were detected by Western Blot. Results Compared with the control group, the proliferation rate of GLC-82 and A549 cells was 37.56％(P<0.01) and 6.32％(P>0.05) after 24 hours of 20.00μg/ml LCNT treatment indicating LCNT could promote the proliferation of GLC-82 cells. Compared with the EPI group, EPI+LCNT had smaller inhibitory effect on the proliferation of GLC-82 cells, and the inhibition rate of the EPI+LCNT group was 12.14％lower than that of EPI group (P<0.05). Compared with the EPI group, EPI+LCNT could significantly increase the G0/G1 phase ratio of GLC-82 cells (50.42％±1.21％vs. 25.94％± 0.66％, P<0.01) and A549 cells (54.92％±1.71％vs. 38.63％±0.69％, P<0.01), decrease the S phase ratio of GLC-82 cells (34.21％±0.96％vs. 59.68％±1.25％, P<0.05), and prevent the early apoptosis of GLC-82 cells without affecting apoptosis of A549 cells. Moreover, in the EPI+LCNT group, the expression of P53 protein in GLC-82 and A549 cells was down-regulated (P<0.05), and the expression of Bcl-2 protein in GLC-82 cells was up-regulated (P<0.01) and no significant change in A549 cells (P>0.05). Conclusions Comparing with the EPI, the combination of LCNT and EPI has less proliferation inhibition and apoptosis induction on GLC-82 cells, and without significant effect on A549 cells. LCNT can promote the proliferation of GLC-82 cells and block the cell cycle at G0/G1 phase. This mechanism may be related to down-regulation of P53 protein and up-regulation of Bcl-2 protein expression.
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OBJECTIVE:To study the inhibitory effect of dihydrotanshinone(DTS)on human lung cancer GLC-82 cell and its mechanism. METHODS:After treated with 0(blank control),5,10,20,40,80 and 100 μg/ml DTS for 24 and 48 h,MTT as-say was used to measure the inhibition rates and IC50 of cells;cell apoptosis was detected by flow cytometry after treated with 17.85 μg/ml DTS for 12,24 and 48 h to calculate apoptotic rate;Western blot was used to detect the protein expressions of Bcl-2, Bax and Caspase-3. RESULTS:Compared with blank control group,different concentrations of DTS inhibited the proliferation of cells;24 and 48 h maximal inhibition rate were 54.48% and 64.95%,respectively;IC50 were 62.36 and 33.94 μg/ml. DTS could induce cell apoptosis in positive time dependent manner,and the range of inhibition rate was 5.6%-29.6%;Western blot showed DTS could down-regulate the expression of Bcl-2 protein and up-regulate the expression of Caspase-3 protein (P<0.01 or P<0.05). CONCLUSIONS:DTS have significant inhibitory effect on GLC-82 cells and also induce cell apoptosis,by a possible mech-anism of down-regulating the expression of Bcl-2 protein and up-regulating the expression of Caspase-3 protein.
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Objective:This study aimed to investigate the effects and the molecular mechanism of JNJ-7706621 on cell cycle and apoptosis of breast cancer cell lines. Methods:Breast cancer cell lines T47D and MDA-MB-231 were cultured in vitro and treated with JNJ-7706621 at varying concentrations. MTT assay was used to measure cell proliferation. Flow cytometry was applied to analyze the distribution of cell cycle and apoptotic rates. Western blot was performed to analyze the expression of cyclin B1-CDK, the phosphoryla-tion levels of CDK1Thr161 and CDK1Tyr15, as well as the expression of p53, Bcl-2, caspase3 and poly(ADP-ribose) polymerase (PARP). Results:JNJ-7706621 inhibited the proliferation of the T47D and MDA-MB-231 cells in a dose-and time-dependent manner. Flow cytometry showed that the T47D and the MDA-MB-231 cells in the G2/M-phase significantly increased after treatment at varying concentrations (0, 1, 2, 4μM) of JNJ-7706621:the G2/M-phase rates at the corresponding concentrations were (12.66±1.55)%, (20.63± 1.32)%, (23.20±1.82)%, and (32.19±2.37)%, respectively, for the T47D cells (P<0.05), and the G2/M-phase rates were (16.22±1.48)%, (21.45±0.85)%, (25.25±1.26)%, and (31.08±1.16)%, respectively, for the MDA-MB-231 cells (P<0.05). The rates of apoptotic cells were also significantly increased (P<0.05). Western blot results indicated that JNJ-7706621 exerted a slight effect on the expression of CDK1 and p53 and that the phosphorylation level of CDK1 decreased at the Thr161 site but increased at the Tyr15 site. In addition, cleaved caspase3 and PARP increased, whereas Bcl-2 and cyclinB1 decreased significantly. Conclusion:JNJ-7706621 can significantly inhibit the proliferation of breast cancer cell lines T47D and MDA-MB-231 by inducing cell cycle arrest and apoptosis, which may be associated with the downregulation of the CDK1 phosphorylation at the Thr161 site.