Replication and Pathology of Duck Influenza Virus Subtype H9N2 in Chukar / 生物医学与环境科学（英文）

To investigate the susceptibility of Chukars to duck avian influenza virus H9N2 and explore their role in interspecies transmission of influenza viruses. Chukars were inoculated with duck avian influenza viruses H9N2. The present study demonstrated that inflammatory lesions and virus antigen were present in the trachea, bronchus, and parabronchus, and the viruses could be isolated from throat swabs and lung tissue homogenate supernatants. At 14 d post virus inoculation, anti-H9 influenza virus antibody in the serum was detected. The results indicated that Chukars are susceptible to duck avian influenza virus and serve as an intermediate host, thereby facilitating viral gene evolution and supporting the need for continued surveillance of epidemiology and evolution of the influenza virus in Chukars.

Prognostic Significance of MiR-34a Expression in Patients with Gastric Cancer after Radical Gastrectomy / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>MiR-34a dysregulation has been implicated in tumorigenesis and progression of gastric cancer, but its role in prognosis of patients with gastric cancer remains unknown. The aim of this study was to investigate the expression and prognostic significance of miR-34a in gastric cancer patients after radical gastrectomy.</p><p><b>METHODS</b>Quantitative real-time polymerase chain reaction was performed to detect the expression of miR-34a in human gastric cancer cell lines and tissues in 76 patients with gastric adenocarcinoma from China. Results are assessed for association with clinical features and overall survival (OS) using Kaplan-Meier analysis. Prognostic values of miR-34a expression and clinical outcomes were evaluated by Cox regression analysis. A molecular prognostic stratification scheme incorporating miR-34a expression was determined using receiver operating characteristic analysis.</p><p><b>RESULTS</b>The results show that the expression level of miR-34a was decreased in human gastric cancer cell lines and tissues, and down-regulated expression of miR-34a was associated with Lauren classification (P = 0.034). Decreased miR-34a expression in gastric cancer tissues was positively correlated with poor OS of gastric cancer patients (P = 0.013). Further multivariate Cox regression analysis suggested that miR-34a expression was an independent prognostic indicator for gastric cancer (P = 0.027). Applying the prognostic value of miR-34a expression to tumor node metastasis (TNM) stage system showed a better prognostic value in patients with gastric cancer than miR-34a expression (P = 0.0435) or TNM stage (P = 0.0249) alone.</p><p><b>CONCLUSION</b>The results reinforce the critical role for the down-regulated miR-34a expression in gastric cancer and suggest that miR-34a could be a prognostic indicator for this disease.</p>

Apoptotic mechanism of gastric carcinoma cells induced by matrine injection / 中华胃肠外科杂志

<p><b>OBJECTIVE</b>To investigate the mechanism of gastric carcinoma cells apoptosis induced by matrine injection in vitro.</p><p><b>METHODS</b>Effects of 24, 48, 72, 96 h incubation with different concentrations (0.25-1.5 g/L) of matrine injection on proliferation of SGC-7901 cells were evaluated using 3-4,5-dimethylthiazol-2-yl-2,5-diphenyltetrazolium bromide (MTT) assay. The cellular morphology of SGC-7901 cells was observed by transmission electron microscope (EM). Flow cytometry was used to analyze the apoptosis of SGC-7901 cells by staining with annexin V-FITC/PI. The expression of Fas/FasL was examined by flow cytometry using specific antibody. The activity of caspase-3 was measured by spectrofluorometry.</p><p><b>RESULTS</b>Matrine injection could inhibit the proliferation of SGC-7901 cells in a dose- and time-dependent manner. The typical morphological changes of apoptosis were observed after incubation with 1.0 g/L matrine injections for 48 h. The apoptosis rates of 0.5 g/L, 1.0 g/L and 1.5 g/L groups were 39.80%, 58.11% and 79.00% respectively. The apoptotic cells in matrine injection group were mainly early apoptotic cells, and those in 5-FU group were mainly late apoptotic cells and necrotic cells. Spectrofluorometry revealed FI levels of Fas and FasL were equal, which were both correlated with apoptosis rate. The activity of caspase-3 increased with the elevation of matrine concentration, and was correlated with the apoptosis rate.</p><p><b>CONCLUSION</b>Matrine injection can induce apoptosis of SGC-7901 cells through the up-regulation of Fas/FasL expression and activation of caspase-3.</p>

Antitumor and immune-modulating effects of Scutellaria barbata extract in mice bearing hepatocarcinoma H22 cells-derived tumor / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the effects of Scutellaria barbata extract (ESB) in suppressing tumor growth and modulating the immune functions in mice bearing tumors derived from hepatocarcinoma H22 cells.</p><p><b>METHODS</b>Fifty mice inoculated subcutaneously with H22 cells were equally divided into the model group, high-, moderate-, and low-dose ESB groups, and 5-Fu group, with corresponding treatments for 10 days. Another 10 mice with only saline injection served as the normal control group. The body weight, tumor mass, thymus index and spleen index of the mice were measured, and the lymphocyte proliferation activity, NK cell activity and interleukin-2 (IL-2) production by the splenocytes were detected.</p><p><b>RESULTS</b>Moderate- and high-dose ESB significantly suppressed the tumor growth with tumor inhibition rate of 28.68% and 36.98%, respectively. ESB treatment at moderate and high doses significantly increased the thymus index and spleen index (P < 0.01), which were decreased significantly in 5-Fu group. The lymphocyte proliferation activity, NK cell activity and IL-2 production by the splenocytes were significantly lower in the model group than in the normal group (P < 0.05). Compared with the model group, ESB at the high dose obviously increased the three indexes above mentioned. The NK cell activity was also significantly improved in moderate-dose ESB group (P < 0.05).</p><p><b>CONCLUSION</b>ESB can suppress the growth of H22 implant tumor and enhance the immune function of the tumor-bearing mice.</p>

Effect of irradiation-induced pcDNA3.1-Egr.1p-p16 on cell apoptosis and cell cycle of JF305 cells / 南方医科大学学报

<p><b>OBJECTIVE</b>To observe the effect of pcDNA3.1-Egr.1p-p16 plasmid on apoptosis and cell cycle of pancreatic carcinoma JF305 cell line.</p><p><b>METHODS</b>JF305 cells were cultured and transfected with pcDNA3.1-Egr.1p-p16 plasmid via Lipofectamine(TM) 2000, followed by irradiation by 6MV-X at 4 Gy (dose rate 2.50 Gy/min). The cell cycle and cell apoptosis changes were analyzed by flow cytometry.</p><p><b>RESULTS</b>In cells infected with pcDNA3.1-Egr.1p-p16 plasmid and those with pcDNA3.1-Egr.1p-p16 plasmid infection before 4 Gy irradiation, the percentages of viable apoptotic cells were 6.4% and 10.4%, and those of advanced stage apoptotic or dead cells were 16.8% and 33.8%, significantly higher than those in the control group (P<0.05). JF305 cell apoptosis in 4 Gy irradiation group was obviously increased in comparison with non-irradiated plasmid-infected cells (P<0.05). Irradiation resulted in a predominant G(2) arrest of the plasmid-infected JF305 cells. Both pcDNA3.1-p16 plasmid and pcDNA3.1-Egr.1p-p16 plasmid infections could induce G1 arrest of JF-305 cells, and irradiation did not produce significant changes in G(1)-arrested cells in the two plasmid infection groups, but cells arresting at G(2) phase increased.</p><p><b>CONCLUSION</b>pcDNA3.1-Egr.1p-p16 can induce JF-305 cells apoptosis, which is enhanced by irradiation. pcDNA3.1-Egr.1p-p16 tranfection may result in G(1) arrest of the cells, and when combined with irradiation, the cells arrested at G(2) phase can increase.</p>

HER-2 expression in local advanced breast cancer and the efficacy of neoadjuvant chemotherapy regimens / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the relationship between HER-2 expression and the efficacy of neoadjuvant chemotherapy in local advanced breast cancer.</p><p><b>METHODS</b>Different neoadjuvant chemotherapy regimens, namely CMF, CEF, and NEF, were administered in 132 patients with local advanced breast cancer for 2 cycles, each lasting for 28 days. According to the criteria recommended by WHO, the efficacy and safety of the regimens were evaluated after two cycles of neoadjuvant chemotherapy. HER-2 expression was examined by immunohistochemistry using specific monoclonal antibodies before chemotherapy and after surgery.</p><p><b>RESULTS</b>The overall response rate (RR) of CMF, CEF, and NEF regimens were 39.5% (17/43), 54.3% (25/46) and 72.1% (31/43), with incidence of leukopenia of 34.9% (15/43), 58.7% (27/46) and 60.5% (26/43), respectively. Other adverse effects including decreased hemoglobin (Hb) level, thrombocytopenia, gastrointestinal irritation and alopecia were similar between the 3 groups (P>0.05). No significant variation in HER-2 expression occurred after administration of the 3 regimens. The overall RR to CMF regimen in HER-2-negative breast cancer patients was significantly higher than that in HER-2-positive patients, but showed no significant difference with CEF and NEF regimens.</p><p><b>CONCLUSION</b>HER-2 expression is not decreased after neoadjuvant chemotherapy in breast cancer patients, and HER-2-positive breast cancer can be resistant to CMF regimen, but not to CEF and NEF regimens.</p>

Synergism between a siRNA targeted to survivin and 5-FU in inhibiting MCF-7 cell proliferation in vitro / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the role of small interfering RNA (siRNA) targeted to survivin in combination with 5-fluorouracil (5-FU) in inhibiting the proliferation of MCF-7 cells.</p><p><b>METHODS</b>A siRNA targeted to survivin was synthesized and transfected into MCF-7 cells via lipofectin. Changes of the cell growth activity in response to combined treatment with survivin siRNA and 5-FU or 5-FU treatment alone was evaluated by MTT assay. The Q method of Jin Zhenjun was used to evaluated synergism between the synthesized siRNA and 5-FU.</p><p><b>RESULTS</b>Treatment with 5 nmol/L siRNA reduced the IC50 of 5-FU from 4.42 to 1.18 microg/ml, and the inhibitory effect of combined treatment on MCF-7 cells was higher than that of 5-FU alone (F=26.74, P<0.01). Synergism effect was observed between 5-FU at lower concentrations and survivin siRNA.</p><p><b>CONCLUSION</b>siRNA may enhance the effectiveness of 5-FU in inhibiting the proliferation of MCF-7 cells.</p>

Effects of siRNA targeted to survivin in suppressing proliferation and inducing apoptosis in breast cancer MCF-7 cells / 中华肿瘤杂志

<p><b>OBJECTIVE</b>Blocking the expression of survivin with RNA interference techniques, the effects of suppressing proliferation and inducing apoptosis of breast cancer MCF-7 cells were investigated.</p><p><b>METHODS</b>A siRNA eukaryotic expression vector against survivin was constructed and transfected into breast cancer MCF-7 cells with lipofectamine 2000. The changes of survivin expression were detected by semi-quantitive RT-PCR and immunohistochemistry. The effect of suppressing proliferation of MCF-7 cell was detected by MTT assay. The effect of inducing MCF-7 cell apoptosis was detected by TUNEL assay.</p><p><b>RESULTS</b>The sequence-specific siRNA can efficiently block the expression of survivin both at mRNA and protein levels. The expression inhibition rate was 64.9% at mRNA level detected by semi-quantitive RT-PCR and 79.7% at protein level detected by immunohistochemistry. Blocking the expression of survivin can suppress proliferation of MCF-7 cells significantly. At 24 and 48 h after the cells were reseeded, the proliferation inhibition rates were 31.6% and 33.0%, respectively. At 24 h after transfection, apoptosis was induced in 12.9% of the cells as detected by TUNEL assay.</p><p><b>CONCLUSION</b>Blocking the expression of survivin with RNA interference technology can significantly suppress proliferation of MCF-7 cells and induce apoptosis to a certain degree. RNAi targeted to survivin has a potential value in gene therapy of breast cancer.</p>

siRNA targeted against survivin induces apoptosis of pancreatic cancer cells / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the effect of a sequence-specific small interfering RNA (siRNA) in suppressing survivin expression and cell proliferation and inducing apoptosis of PC-2 cells.</p><p><b>METHODS</b>The plasmid expression vector of siRNA targeted against survivin was constructed and transfected into PC-2 cells with Lipofectamine 2000. The changes of survivin expression were detected by semi-quantitative RT-PCR and immunohistochemical SP methods. The effect of siRNA in suppressing the proliferation of PC-2 cells was detected by MTT assay, and its role in inducing PC-2 cell apoptosis evaluated by flow cytometry.</p><p><b>RESULTS</b>The sequence-specific siRNA effectively suppressed survivin expression at both mRNA and protein levels with inhibition rate of 81.25% at mRNA level and 74.24% at protein level. Survivin expression suppression significantly inhibited the proliferation of PC-2 cells, and at 24 and 48 h after cell seeding, the proliferation inhibition rate was 28.00% and 33.38% respectively; 24, 48 h after the transfection, apoptosis occurred in 8.46% and 7.53% of the cells, respectively.</p><p><b>CONCLUSIONS</b>The plasmid expression vector for the siRNA against survivin constructed in the study can effectively and specifically suppress survivin expression in PC-2 cells, and blocking survivin expression suppresses PC-2 cell proliferation and induces cell apoptosis. siRNA targeted against survivin has a potential value in gene therapy for pancreatic cancer.</p>

Chemopreventive effect of celecoxib against DMBA-induced breast cancer and its mechanism / 南方医科大学学报

<p><b>OBJECTIVE</b>To evaluate the chemopreventive effect of celecoxib, a specific cyclooxegenease-2 (COX-2) inhibitor, on chemically induced breast cancer of rats and its effect on COX-2 expression.</p><p><b>METHODS</b>7, 12-dimethylbenz anthracene (DMBA) was administered intragastrically in SD female rats to establish breast cancer models, which were divided subsequently into control group, tamoxifen group and celecoxib group to receive different treatments accordingly. The occurrence rate of breast cancer was observed and the effect of celecoxib on COX-2 and vascular endothelial growth factor (VEGF) expressions assayed by immunohistochemical SP method.</p><p><b>RESULTS</b>The incidence of breast cancer in tamoxifen group (48.15%) and celecoxib group (50.00%) were both significantly lower than that in the control group (85.71%; P=0.003 and P=0.004, respectively). The positivity rate of COX-2 expression in celecoxib group (28.57%) was significantly lower than those of tamoxifen group (48.15%) and control group (83.33%; P=0.001 and P=0.035, respectively). The positivity rate of VEGF expression in celecoxib group (42.86%) was significantly lower than that of control group (79.17%, P=0.023), but comparable with that in tamoxifen group (46.15%, P=0.863).</p><p><b>CONCLUSION</b>Celecoxib can significantly suppress DMBA-induced breast cancer in female rats possibly through down-regulation of COX-2 and VEGF expressions.</p>

Knockdown of survivin expression by small interfering RNA suppresses proliferation of two human cancer cell lines / 中国医学科学杂志(英文版)

<p><b>OBJECTIVE</b>To construct an expression vector of small interfering RNA (siRNA) against survivin and observe its effects on survivin expression and proliferation of human pancreatic cancer cell line PC-2 and breast cancer cell line MCF-7.</p><p><b>METHODS</b>Constructed an expression vector of siRNA against survivin and transfected it into PC-2 and MCF-7 cells using lipofectamine 2000. The expression of survivin was detected by semi-quantitive RT-PCR and immunohistochemistry, and its effects on proliferation of PC-2 and MCF-7 cells were detected by MTT assay.</p><p><b>RESULTS</b>The introduction of sequence-specific siRNA could efficiently suppress survivin expression at both mRNA and protein levels in the two cancer cell lines. In PC-2 cells, the expression inhibition rates were 81.25% at mRNA level and 74.24% at protein level. In MCF-7 cells, the expression inhibition rates were 64.91% at mRNA level and 79.72% at protein level. The proliferation of PC-2 and MCF-7 cells was also suppressed, and 24 and 48 hours after the cells were reseeded, the proliferation inhibition rates of PC-2 cells were 28.00% and 33.38%, and that of MCF-7 cells were 31.58% and 33.02%, respectively.</p><p><b>CONCLUSIONS</b>The expression vector of siRNA against survivin can block survivin expression in PC-2 and MCF-7 cells efficiently and specifically. Down regulation of survivin expression can suppress proliferation of PC-2 and MCF-7 cells. Survivin RNAi may have potential value in gene therapy of human cancers.</p>

Anti-tumor effect of pcDNA3. 1-Egr. 1p-p16 gene combined with radiotherapy in tumor-bearing nude mice / 中南大学学报(医学版)

OBJECTIVE@#To investigate the optimal doses of X-ray irradiation and plasmid injection in the anti-tumor effect of the pcDNA3. 1-Egr. 1p-p16 gene combined with radiotherapy in vivo.@*METHODS@#We observed the anti-tumor effect of the pcDNA3. 1-Egr. 1p-p16 gene combined with radiotherapy with different doses of X-ray irradiation (2, 10, 20 Gy) and plasmid injection (10, 20, 30 microg) in nude mice with JF-305 pancreatic carcinoma, and detected the expression of p16 in tumor by RT-PCR.@*RESULTS@#The tumor growth rate of the nude mice irradiated locally with 20 Gy X-rays after the plasmid injection was significantly lower (P < 0.05 ) than that of the nude mice irradiated locally with 2 Gy or 10 Gy X-ray 3 days after the irradiation. The tumor growth rate of the nude mice injected locally with 20 microg or 30 microg plasmid was significantly lower (P <0.05 ) than that of the nude mice injected locally with 10 microg plasmid. Both pcDNA3. 1-Egr. 1p-p16 group and pcDNA3. 1-Egr. 1p-p16 +20 Gy group had p16 mRNA expression, but the mRNA level of pcDNA3. 1-Egr. 1p-p16 +20 Gy group was higher than that of pcD- NA3. 1-Egr. 1p-p16 group.@*CONCLUSION@#In the pcDNA3. 1-Egr. 1p-p16 gene combined with radiotherapy in vivo the optimal dose of X-ray irradiation was 20 Gy and the optimal dose of plasmid injection was 20 microg. The anti-tumor effect of pcDNA3. 1-Egr. 1p-p16 combined with radiotherapy is better than that of radiotherapy or gene therapy alone, which may be related with the enhanced p16 expression in tumor after the irradiation.