Effects of metformin on human oral cancer KB cell proliferation and apoptosis in vitro / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the effects of metformin on the proliferation and apoptosis of human oral cancer cell line KB in vitro.</p><p><b>METHODS</b>Human oral cancer cell line KB was exposed to different doses of metformin (0, 1.25, 2.5, 5, 10, and 20 mmol/L), and the changes in cell viability were detected using MTT assay. Colony formation of the cells was observed following an 8-day metformin exposure. The changes in mitochondrial membrane potential were measured by JC-1 assay, and PI staining was used to observe the cell apoptosis. Western blotting was employed to detect the changes in the protein expressions of GRP78 and activated caspase-3.</p><p><b>RESULTS</b>Metformin exposure caused time- and dose-dependent suppression of KB cell proliferation, and exposure to 5 mmol/L metformin for 24, 48 and 72 h resulted in cell survival rates of 68.0%, 36.9%, and 14.5%, respectively. Metformin significantly inhibited KB cell colony formation. Exposure of the cells to increased concentrations of metformin gradually increased the apoptotic rate and decreased mitochondrial membrane potential. Metformin caused an initial up-regulation followed by a down-regulation of GRP78 expression in KB cells and increased the expression of activated caspase-3.</p><p><b>CONCLUSION</b>Metformin can inhibit the proliferation and induce apoptosis of KB cells, the mechanism of which may involve the activation of the mitochondrial apoptotic pathway and endoplasmic reticulum stress.</p>

Glycosylation inhibitor 2-deoxy-D-glucose sensitizes oral cancer cells to TRAIL-induced apoptosis / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the effect of 2-deoxy-D-glucose (2-DG) in enhancing the sensitivity of oral cancer cells to tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-induced apoptosis.</p><p><b>METHODS</b>The oral cancer cell line KB was incubated in the presence of different concentrations (0, 0.625, 1.25, 2.5, 5, and 10 mmol/L) of 2-DG with or without TRAIL (200 ng/ml). The cell viability was measured using MTT assay and cell apoptosis was detected using flow cytometry with propidium iodide (PI) staining. KB cells treated with 5 mmol/L 2-DG with or without TRAIL for 0, 6, 16, or 24 h were examined with Western blotting for protein expressions of death receptor 5 (DR5) and caspase-3.</p><p><b>RESULTS</b>Treatment of the cells with 5 mmol/L 2-DG for 24, 48 and 72 h resulted in a cell viability of 25.25%, 69.06%, and 59.19%, respectively. Combined treatment with 5 mmol/L 2-DG with TRAIL for 24 significantly enhanced the cell apoptotic rate (72.5%) as compared to the rate induced by TRAIL alone (45.3%) and by 2-DG (15.9%) alone. 2-DG treatment markedly up-regulated DR5 and caspase-3 expression and enhanced the inhibitory effect of TRAIL on cell colony formation.</p><p><b>CONCLUSION</b>2-DG sensitizes oral cancer cells to TRAIL- induced apoptosis by up-regulating DR5 and caspase-3 expressions.</p>

Small interfering RNA-mediated RIP1 knockdown enhances L-OHP sensitivity of human oral squamous carcinoma cells / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the effect of small interfering RNA-mediated receptor-interacting protein kinase 1 (RIP1) knockdown on the sensitivity of human oral squamous carcinoma cells to to oxaliplatin (L-OHP)-induced apoptosis and explore a new target for clinical treatment of oral squamous carcinoma.</p><p><b>METHODS</b>The viability of human oral squamous carcinoma cell line KB exposed to different concentrations (0, 0.25, 0.5, 1, 2, 4 µmol/L) of L-OHP were detected by MTT assay. PI/Annexin V staining was used to observe cell apoptosis in naive KB cells, cell and transfected with pSH1Si-RIP1 or with the empty plasmid. Western blotting was used to detect RIP1 expression in KB cells exposed to L-OHP and in cells transfected with pSH1Si-RIP1.</p><p><b>RESULTS</b>Exposure to L-OHP (1µmol/L) for 24, 48, 72 h resulted in KB cell survival rates of 67.66%, 55.17%, and 41.34%, respectively, but the cell apoptosis rate was only 9.6% following a 24-h exposure. KB cells transfected with pSH1Si-RIP1 showed an apoptotic rate of 9.4%, which increased to 29.1% following L-OHP exposure. RIP1 expression was first up-regulated and then down-regulated in KB cells treated with L-OHP, and was significantly reduced after cell transfection with pSH1Si-RIP1.</p><p><b>CONCLUSION</b>Suppression of RIP1 expression increases the apoptotic rate of human oral squamous carcinoma cells, suggesting the potential of RIP1 as a new candidate target for clinical treatment of oral squamous carcinoma.</p>

Small interfering RNA-mediated glucose-regulated protein 78 knockdown enhances chemosensitivity of breast cancer cells to cisplatin / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the effect of small interfering RNA-mediated glucose-regulated protein 78 (GRP78) knockdown on the chemosensitivity of breast cancer cells to cisplatin.</p><p><b>METHODS</b>Human breast cancer cell line MDA-MB-231 was exposed to different doses of cisplatin (0, 1, 2, 4, 8, and 16 µmol/L), and the changes in cell viability were detected using MTT assay. PI/Annexin V staining was used to observe the apoptosis of the cells in response to transfection with a small interfering RNA targeting GRP78 (pSH1Si-GRP78). Western blotting was employed to detect GRP78 expression in pSH1Si- GRP78-transfected cells after exposure to 8 µmol/L cisplatin for 24, 48 and 72 h.</p><p><b>RESULTS</b>Exposure of the cells to 8 µmol/L cisplatin for 24, 48 and 72 h resulted in a cell survival rate of 83.13%, 54.22% and 35.79%, respectively, but the cell apoptosis rate was only 10.8% at 24 h. Transfection of MDA-MB-231 cells with pSH1Si-GRP78 caused a cell apoptosis rate of 24.6%, which increased to 48.9% in cells with both pSH1Si-GRP78 transfection and cisplatin exposure. Cisplatin exposure caused an initial up-regulation followed then by a down-regulation of GRP78 expression in MDA-MB-231 cells, while pSH1Si-GRP78 transfection produced an obvious down-regulation of GRP78 expression.</p><p><b>CONCLUSIONS</b>Inhibition of GRP78 expression increases the apoptosis and enhance cisplatin chemosensitivity of breast cancer cells in vitro, suggesting the value of GRP78 as a potential therapeutic target in the clinical treatment of breast cancer.</p>

Immediate reconstruction of palatomaxillary defects by mandibular osteomuscular flap pedicled with temporalis and radial forearm free flap / 中华显微外科杂志

Objective To evaluate the clinical effect of mandibular osteomuscular flap pedicled with temporalis and radial forearm free flap to repair palatomaxillary defects. Methods From March 2008 to March 2011,nine patients with palatomaxillary defects following malignant tumor ablation,were repaired with mandibular osteomuscular flap pedicled with temporalis and radial forearm free flap. According to Brown's classification for the maxillectomy defect,eight cases were type Ⅱ B and 1 case was type Ⅱ C. There were 6 males and 3 females with an average age of 57 years(range,34-68 years). Results All the 9 osteomuscular flaps and forearm flaps survived.The patients were followed up for 12 to 24 months with an average of 14 months. The patients acquired satisfactory appearance and complete functional restoration except 1 case of chondrosarcoma of recurrence was encountered 6 months after operation. Conclusions Palatomaxillary defects were reconstructed by mandibular osteomuscular flap pedicled with temporalis and radial forearm free flap immediately.It is easy to elevate,safe,and there were no donor site problems.This is an ideal method of repairing the palato maxillary defects.

Effects of Acute Exhausted Exercise on the Myocardial HSP70 and Plasma ANP of Rats in a High Temperature Environment / 中国运动医学杂志

Objective To investigate the effect of acute exhausted exercise in high temperature environment on the expression of myocardial HSP70 and plasma ANP level of in rats. Methods Forty eight male Sprague-Dawley rats was randomly and equally assigned to the following six groups:control group(C),exercise group(E),one-hour heat exposure group (H), heat exposure and exercise group (HE), exercise and 24 hours after exercise group(E'),heat exposure and 24 hours after exercise(HE'). Each group consisted of 8 rats. Rats in E,HE,E' and HE' ran on a treadmill until exhaustion, while rats in H and H' were exposed in a high temperature environment (33℃ ,50%RH) for one hour. Rats in C,E,HE and H were killed immediately after exercise or heat exposure. Rats in HE' and E' were killed 24 hours after exercise. Samples from myocardium and serum were collected for determining HSP70,ANP and CK-MB. Results(1) HSP70 levels in groups E and E' are significantly higher than that in group C(P<0.05 and P<0.01,respectively),and the level in group HE' is significantly higher than that in groups H and E'(P<0.01 );The HSP70 level in group H is significantly higher than that in group C. (2) The ANP and CK-MB levels in group E are Significantly higher than that in group C.and in group HE is higher than in group H (P<0.05);The HSP70 levels in group E' and HE' significantly decrease comparing to that in groups E and HE (P<0.01). Conclusions(1)Both heat exposure and exercise can induce the increased expression of myocardial HSP70 in rats and the peak expression is seen 24 hours after exercise. The increased expression of HSP70 may have protective effects on the heat-induced myocardial injury. (2) The increased ANP levels in plasma immediately after exhausted exercise improves the blood circulation in myocardium and hints the potential possibility of myocardial damage. However,the high temperature environment does not strengthen the increase of plasma ANP level that caused by exhaustive exercise.

Changes of resting heart rate in patients with essential hypertension and its clinical significance / 中国综合临床

Objective To study the relationship between resting heart rate(RHR)and essential hypertension(EH).Methods 215 patients with EH and 82 healthy subjects underwent RHR detection.The relationship between RHR and the state of EH was analyzed.Results RHR in EH group was significantly higher than that in normal group[(78.9±9.1)bpm vs(69.5±10.9)bpm,P＜0.01)],RHR in different stages of EH was significantly different(F=21.280,P＜0.01,respectively),and increased with grades(P＜0.05 orP＜0.01).RHR in EH patients complicated with left ventricle hypertrophy(LVH)was higher than those with no LVH[(83.9±9.1)bpm vs (75.9±8.9)bpm,P＜0.01].There was positive correlation between RHR and LVH(r=0.8097,P＜0.01).Conclusion RHR is related to the development and progress of EH,and it may be one of the index for estimating the state of EH.

Study on MDA and SOD of Cervical Cord at Early Stage after Decompression of Chronic Compressive Spinal Cord Injury / 昆明医科大学学报

Objective We investigate lipid peroxidation of compressed myeloid tissue at early stage after decompression of chronic compressive spinal cord injury.Method SOD and MDA of compressed myeloid tissue are measured respectively before compression,before decompression and 3h after decompression.Result Increased MDA while decreased SOD of compressed myeloid tissue at 3h after decompression than before decompression.Conclusion The increased lipid peroxidation of compressed myeloid tissue at early stage after decompression of chronic compressive spinal cord injury.It is possible that it was resulted from ischemical reperfusion injury.