ABSTRACT
Aim To explore the effect of ferroptosis inducer Erastin combined with Shikonin on the anti-tumor activity of colorectal cancer cells and its mechanism.Methods Erastin(0,4,8,16,32,64 μmol·L-1)and Shikonin(SW-480:0, 0.5,1,2,4,8 μmol·L-1 with SW-620:(0,0.2,0.4,0.8,1.6,3.2 μmol·L-1)alone and 10 μmol·L-1 Erastin combined with various concentrations of Shikonin were used to treat colorectal cancer cells SW480 and SW620; Cell viability was detected by CCK-8 method and the apoptosis was detected by AnnexinV/PI double staining.The changes of active oxygen content in colorectal cancer cells were measured by ROS detection kit, and the changes of intracellular lactic acid content in SW480 and SW620 were measured by 10 μmol·L-1 Erastin alone or in combination with 2 μmol·L-1 and 1 μmol·L-1 Shikonin, respectively.The protein expressions of Bax, Bcl-2, PARP1, Caspase3,Caspase8,AKT and P-akt in SW480 and SW620 cells were detected by Western blot.Results The results of CCK-8 showed that the combination group could significantly inhibit the viability of colorectal cancer cells and the apoptotic rate was the highest.At the same time, lactic acid was inhibited most obviously.The content of intracellular reactive oxygen species and apoptosis-related proteins also changed significantly.Conclusions Erastin combined with Shikonin can synergistically induce the apoptosis of colorectal cancer cells.The mechanism may be inhibiting the production of lactic acid in tumor cells, increasing the content of reactive oxygen species in tumor cells, inhibiting the AKT signaling pathway, and activating pro-apoptotic proteins to induce colorectal cancer cell apoptosis.
ABSTRACT
Oridonin, which is an ent-kaurene diterpenoid isolated from traditional Chinese medicine Rabdosia rubescens, displays various bioactivities, including anti-inflammation, anti-bacteria and anti-tumor. This study aimed to investigate the effect of oridonin on apoptosis of triple-negative breast cancer MDA-MB-231 cells and its underlying mechanisms. The inhibitory effect of oridonin on proliferation of MDA-MB-231 cells was measured by MTT assay; Apoptosis was analyzed by flow cytometry with PI staining and Annexin V-FITC/PI staining; Intracellular reactive oxygen species (ROS) level was determined by ROS detection kit, and expressions of PARP, Bcl-2, caspase-3 were analyzed by Western blot. The results showed that oridonin exhibited a significant effect in inducing apoptosis of MDA-MB-231 cells, enhancing intracellular ROS level, down-regulating expression of Bcl-2 protein, and promoting cleavage of caspase-3 and its substrate PARP. These results indicated that the apoptosis-inducing effect of oridonin on MDA-MB-231 cells might be correlated with increase of intracellular ROS level, down-regulation of Bcl-2 protein and activation of caspase-3.
ABSTRACT
<p><b>OBJECTIVE</b>To investigate the role of monocarboxylate transporter 1 (MCT1) in enhancing the sensitivity of breast cancer cells to 3-bromopyruvate (3-BrPA).</p><p><b>METHODS</b>The inhibitory effect of 3-BrPA on the proliferation of breast cancer cells was assessed with MTT assay, and brominated propidium bromide single staining flow cytometry was used for detecting the cell apoptosis. An ELISA kit was used to detect the intracellular levels of hexokinase II, lactate dehydrogenase, lactate, and adenosine triphosphate, and Western blotting was performed to detect the expression of MCT1. MDA-MB-231 cells were transiently transfected with MCT1 cDNA for over-expressing MCT1, and the effect of 3-BrPA on the cell proliferation and adenosine triphosphate level was deteced.</p><p><b>RESULTS</b>3-BrPA did not produce significant effects on the proliferation and apoptosis of MDA-MB-231 cells, and the cells treated with 200 µmol/L 3-BrPA for 24 h showed an inhibition rate and an apoptosis rate of only 8.72% and 7.8%, respectively. The same treatment, however, produced an inhibition rate and an apoptosis rate of 84.6% and 82.3% in MCF-7 cells, respectively. In MDA-MB-231 cells with MCT1 overexpression, 200 µmol/L 3-BrPA resulted in an inhibition rate of 72.44%, significantly higher than that in the control cells (P<0.05); treatment of the cells with 25, 50, 100, and 200 µmol/L 3-BrPA for 6 h resulted in intracellular adenosine triphosphate levels of 96.98%, 88.44%, 43.3% and 27.56% relative to the control level respectively.</p><p><b>CONCLUSION</b>MCT1 can enhance the sensitivity of breast cancer cells to 3-BrPA possibly by transporting 3-BrPA into cells to inhibit cell glycolysis.</p>
ABSTRACT
<p><b>OBJECTIVE</b>To investigate the effect of small interfering RNA (siRNA)-mediated silencing of monocarboxylate transporter 1 (MCT1) on the sensitivity of drug-resistant nasopharyngeal carcinoma HNE1/DDP cells to cisplatin (DDP)-induced apoptosis and explore the possible mechanism.</p><p><b>METHODS</b>The expression of MCT1 was analyzed in HNE1 and HNE1/DDP cells and in HNE1/DDP cells transfected with siRNA using Western blot. MTT assay was used to assess the inhibitory effect of different concentrations of DDP alone or in combination with MCT1 siRNA on the proliferation of HNE1/DDP cells. The apoptosis of cells treated with MCT1 siRNA or/and DDP (8 µmol/L) was assessed using flow cytometry with PI staining, and the mitochondrial membrane potential was detected using JC-1 staining assay; the expressions of Mcl-1, Bak, Bcl-2, and Bax were analyzed using Western blotting.</p><p><b>RESULTS</b>HNE1/DDP cells showed a high expression of MCT1, and MCT1 silencing using siRNA significantly increased the sensitivity of HNE1/DDP cells to DDP (P<0.05) and partly reversed DDP resistance of the cells. MCT1 silencing enhanced the sensitivity of HNE1/DDP cells to DDP-induced apoptosis. Treatment of HNE1/DDP cells with MCT1 siRNA combined with 8 µmol/L DDP for 24 h resulted in an apoptotic rate of (51.23∓2.86)%, significantly higher than that in cells treated with MCT1 siRNA or DDP alone (P<0.05). The combined treatment also reduced the mitochondrial membrane potential, down-regulated the expression of Mcl-1 and Bcl-2, and up-regulated the expression of Bax in the DDP-resistant cells.</p><p><b>CONCLUSION</b>MCT1 siRNA can enhance the sensitivity of HNE1/DDP cells to DDP-induced apoptosis, the mechanism of which may involve the down-regulation of Mcl-1 and Bcl-2 and up-regulation of Bax expression.</p>