Association of RAS mutations in circulating cell-free DNA in the plasma with clinicopathological features of colorectal cancer / 南方医科大学学报

<p><b>OBJECTIVE</b>To detect RAS mutations in the circulating cell-free DNA (cfDNA) in the plasma and explore the their correlation with the clinicopathological features in patients with colorectal cancer.</p><p><b>METHODS</b>Real-time PCR was used to detect RAS mutations in plasma cfDNA and matched tumor tissue DNA samples from 71 colorectal cancer patients. The correlation of RAS mutations with the clinicopathological features of the patients were analyzed.</p><p><b>RESULTS</b>Of the 71 patients with colorectal cancer, 23 (32.39%) showed RAS mutations in the cfDNA and 36 (50.7%) showed RAS mutations in tumor tissue DNA, with a concordance rate of 76.06% in the results between the two samples (Kappa=0.523). RAS mutations in the cfDNA were not related to the patients' age (P=0.072), gender (P=0.320), tumor stage (IVa and IVb, P=0.450), primary tumor position (P=0.324), lung metastasis (P=0.237), CEA level (P=0.284) or CA199 level (P=0.427). The positivity rate of RAS mutations in plasma cfDNA was significantly higher in patients with liver metastasis than those without liver metastasis (P=0.045).</p><p><b>CONCLUSION</b>Plasma cfDNA can be a reliable source of diagnostic DNA to replace the tumor tissue DNA for diagnosis of RAS mutations. RAS mutations in plasma cfDNA occur more frequently in colorectal cancer patients with liver metastasis.</p>

Effect of nitric oxide on the proliferation of AGS gastric cancer cells / 癌症

<p><b>BACKGROUND AND OBJECTIVE</b>Nitric oxide (NO) is involved in many physiologic and pathologic processes. As an important biologic mediator, NO has been the focus of cancer study for its function in tumorigenesis, tumor progression, and death. This study investigated the effect of NO donor sodium nitroprusside (SNP) on the growth and proliferation of gastric cancer cell line AGS.</p><p><b>METHODS</b>The growth inhibition of AGS cells was analyzed using MTT assay. The cell cycle was measured using flow cytometry. The changes of mRNA expression of proliferating cell nuclear antigen (PCNA) and caspase-3 were examined using reverse transcriptase polymerase chain reaction (RT-PCR), and the protein expressions of PCNA and caspase-3 were analyzed using Western blot.</p><p><b>RESULTS</b>Dose-dependent SNP inhibited cell growth and proliferation. When the AGS cells were treated with SNP at 100, 500, 1000, 1500, and 2000 mumol/L for 24 h, the growth inhibition rates were (2.02 +/- 2.96)%, (10.82 +/- 2.21)%, (18.95 +/- 3.35)%, (26.88 +/- 2.54)%, and (42.57 +/- 1.27)%, respectively (P < 0.05). SNP altered the cell cycle in AGS cells. Compared with the control group, treatment with SNP at 100, 500, 1000, 1500, and 2000 mumol/L for 24 h reduced the number of cells in the S phase by 2.29%, 7.8%, 11.34%, 20.49%, and 23.6%, respectively, and enhanced the number of cells in the G1/G0 phases by 3.33%, 9.3%, 13.46%, 21.37%, and 24.73%, respectively (P < 0.05). With the increasing concentration and action time of SNP, the expressions of PCNA mRNA and protein decreased. The expression of caspase-3 mRNA remained unchanged, but procaspase-3 was activated.</p><p><b>CONCLUSION</b>NO not only inhibits cell growth and proliferation, but also induces apoptosis in gastric cancer cells, and such effects of NO showed significant dose-dependent activity.</p>

A novel biosynthetic hybrid scaffold seeded with olfactory ensheathing cells for treatment of spinal cord injuries / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Implantation of tissue-engineered scaffolds is one of the most promising therapeutic strategies for inducing nerve regenerations following spinal cord injuries. In this paper, we report a novel bioengineered hybrid scaffold comprised of three major extracellular matrix (ECM) proteins.</p><p><b>METHODS</b>ECM-scaffolds (ECM-S) were prepared by gelling fibrinogen, fibronectin and laminin using fresh rat plasma. Olfactory ensheathing cells (OECs) were isolated from fresh rat olfactory mucosa, purified under differential adhesion, and assessed by immunofluorescent staining. OECs were seeded onto ECM-S and cultured. The effects of the scaffolds on the seeded cells were detected using the immunofluorescent staining, Western blotting, scanning electron microscopy and transmission electron microscopy.</p><p><b>RESULTS</b>Tissue-engineered ECM-S could be easily molded into mat-like or cylindrical shapes and gelled by addition of fresh plasma. Observations by electron microscopy show that the ECM-S forms a stable three-dimensional porous network. Studies on the effects of the ECM-S on the biological behaviors of OECs in vitro indicate that the scaffold can promote OEC adhesion, proliferation and process extensions. Additionally, OECs seeded on the scaffold maintained the expression of nerve growth factor, matrix metalloproteinase-3 and matrix metalloproteinase-9.</p><p><b>CONCLUSION</b>We developed a biosynthetic hybrid gel which could be used as a scaffold for OEC transplantation; this gel can promote nerve regeneration following spinal cord injuries.</p>