Small interfering RNA-mediated monocarboxylate transporter 1 silencing enhances sensitivity of nasopharyngeal carcinoma HNE1/DDP cells to cisplatin-induced apoptosis / 南方医科大学学报

<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>

Effect of oridonin on apoptosis and intracellular reactive oxygen species level in triple-negative breast cancer MDA-MB-231 cells / 中国中药杂志

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.

Chemical modification endows heparin with low anticoagulant and high antineoplastic activities / 南方医科大学学报

<p><b>OBJECTIVE</b>To evaluate the anticoagulant and antineoplastic activities of chemically modified low-molecular-weight heparin (LMWH).</p><p><b>METHODS</b>LMWH obtained by splitting unfractionated heparin (UFH) with sodium periodate oxidation and sodium borohydride reduction was subjected to acetylation catalyzed by DCC and DMAP to produce acetylated LMWH (ALMWH). The anticoagulant activity of ALMWH was determined in mice, and its antiproliferative and anti-invasion activities was assessed in human breast cancer cells MDA-MB-231 and MFC-7.</p><p><b>RESULTS</b>The anticoagulant activity of LMWH was decreased significantly after acetylation. The concentrations of commercial LMWH* and ALMWH for doubling the coagulation time (CT) were 33.04 µmol/L and 223.56 µmol/L, respectively, and the IC(50) of ALMWH for doubling CT was 6 times of that of LMWH*. ALMWH and LMWH at 0.1, 0.3, 0.9, 2.7 and 8.1 mmol/L both significantly inhibited the proliferation of MDA-MB-231 and MCF-7 cells in a concentration-dependent manner, but ALMWH produced stronger inhibitory effects. The IC(50) of LMWH and ALMWH for inhibiting cell proliferation was 3168.4 µmol/L and 152.6 µmol/L in MCF-7 cells, and 12299.6 µmol/L and 22.2 µmol/L in MDA-MB-231 cells, respectively. ALMWH and LMWH all markedly suppressed the invasion of MDA-MB-231 cells with comparable effects.</p><p><b>CONCLUSION</b>Chemical modification of structure can endow LMWH with a low anticoagulant and high antiproliferative activities.</p>

2-DG enhances TRAIL-induced apoptosis of leukemia HL-60 cells / 中国实验血液学杂志

This study was purposed to investigate the effects of 2-deoxy-D-glucose (2-DG) on sensitizing HL-60 cells to tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-induced apoptosis and its possible mechanism. The proliferative inhibition of HL-60 cells treated with different concentrations of 2-DG and TRAIL was measured by MTT assay. The cells were treated with 2-DG, TRAIL, and 2-DG combined with TRAIL at the concentration < IC50 value, i.e. 10 mmol/L for 2-DG and 100 ng/ml for TRAIL. Apoptosis was analyzed by flow cytometry with PI staining; the expression of RIP1, GRP78, and PARP was analyzed by Western blot; the activity of caspase-3 was detected by special detection kit. The results showed that the combined treatment of HL-60 cells for 48 h induced an apoptotic rate of (45.1 ± 4.3)%, which was significantly higher than that of treated with 2-DG or TRAIL alone; at the same time, the combined treatment potentiated the expression of GRP78 and caspase-3 activity, and down-regulated the expression of RIP1. It is concluded that 2-DG can sensitize HL-60 cells to TRAIL-induced apoptosis, which may be correlated with excessive endoplasmic reticulum stress response, down-regulation of RIP1, and increase of caspase-3 activity.