Synergistic tumoricidal effect between celecoxib and adenoviral-mediated delivery of mda-7 in human breast cancer cells

BACKGROUND: Celecoxib, a selective cyclooxygenase 2 (COX-2) inhibitor, blocks growth and promotes apoptosis in breast cancer cells. The PI3K/Akt pathway is important in cell survival, and COX-2 and Akt might promote growth via a positive feedback loop. We have shown that adenoviral delivery of mda-7 (Ad-mda7) in breast cancer down-regulates Akt. We hypothesized that combining Ad-mda7 and celecoxib could mediate tumor suppression in COX-2 overexpressing breast cancer cells. METHODS: Two COX-2 overexpressing human breast cancer cell lines (Her-18 and MDA-MB-436) were treated with celecoxib (20 micromol/L and 50 micromol/L) and Ad-mda7 (multiplicity of infection, 1000 and 2000 viral particles/cell). Adenovirus encoding the luciferase gene was used as a control. We assessed proliferation, cell cycle, apoptosis, prostaglandin E2 production, and changes in protein expression. Statistical analysis was performed by using the Student t test. RESULTS: Regardless of HER-2/neu status, cell growth was markedly inhibited by celecoxib, Ad-mda7, and the combination compared with controls. Celecoxib + Ad-mda7 showed a greater than additive increase in cell death compared with either monotherapy (P < .05) and resulted in cell cycle block and apoptosis (P < .05). Both cell lines showed decreased prostaglandin E2 production after combination treatment compared with controls (P < .05), with decreased expression of COX-2, Akt, and phosphorylated Akt (P < .05). CONCLUSIONS: Enhanced antitumor activity is achieved in breast cancer by combining celecoxib and Ad-mda7 regardless of HER-2/neu status. This occurs through inhibition of COX-2 expression and down-regulation of Akt. Combining Ad-mda7 with COX-2 inhibition provides a novel method of treatment in breast cancer.     

The double-stranded RNA-activated protein kinase mediates radiation resistance in mouse embryo fibroblasts through nuclear factor kappaB and Akt activation.

PURPOSE: Activation of the double-stranded RNA-activated protein kinase (PKR) leads to the induction of various pathways including the down-regulation of translation through phosphorylation of the eukaryotic translation initiation factor 2alpha (eIF-2alpha). There have been no reports to date about the role of PKR in radiation sensitivity. EXPERIMENTAL DESIGN: A clonogenic survival assay was used to investigate the sensitivity of PKR mouse embryo fibroblasts (MEF) to radiation therapy. 2-Aminopurine (2-AP), a chemical inhibitor of PKR, was used to inhibit PKR activation. Nuclear factor-kappaB (NF-kappaB) activation was assessed by electrophoretic mobility shift assay (EMSA). Expression of PKR and downstream targets was examined by Western blot analysis and immunofluorescence. RESULTS: Ionizing radiation leads to dose- and time-dependent increases in PKR expression and function that contributes to increased cellular radiation resistance as shown by clonogenic survival and terminal nucleotidyl transferase-mediated nick end labeling (TUNEL) apoptosis assays. Specific inhibition of PKR with the chemical inhibitor 2-AP restores radiation sensitivity. Plasmid transfection of the PKR wild-type (wt) gene into PKR(-/-) MEFs leads to increased radiation resistance. The protective effect of PKR to radiation may be mediated in part through NF-kappaB and Akt because both NF-kappaB and Akt are activated after ionizing radiation in PKR+/+ but not PKR-/- cells. CONCLUSIONS: We suggest a novel role for PKR as a mediator of radiation resistance modulated in part through the protective effects of NF-kappaB and Akt activation. The modification of PKR activity may be a novel strategy in the future to overcome radiation resistance.     

Slit2 Inhibits Growth and Metastasis of Fibrosarcoma and Squamous Cell Carcinoma

Slits are a group of secreted glycoproteins that play a role in the regulation of cell migration. Previous studies suggested that Slit2 might be a tumor-suppressor gene. However, it remained to be determined whether Slit2 suppressed tumor growth and metastasis in animal models. We showed that Slit2 expression was decreased or abolished in human esophageal squamous cell carcinomas (SCCs) compared to normal tissues by in situ hybridization. Stable transfection of human SCC A431 and fibrosarcoma HT1080 cells with Slit2 gene suppressed tumor growth in athymic nude mice. Apoptosis in Slit2-transfected tumors was increased, whereas proliferating cells were decreased, suggesting a mechanism for Slit2-mediated tumor suppression. This was supported by further analysis indicating that antiapoptotic molecules Bcl-2 and Bcl-xl and cell cycle molecules Cdk6 and Cyclin D1 were down-regulated in Slit2-transfected tumors. Furthermore, wound healing and Matrigel invasion assays showed that the transfection with Slit2 inhibited tumor cell migration and invasion. Slit2-transfected tumors showed a high level of keratin 8/18 and a low level of N-cadherin expression compared to empty vector-transfected tumors. More importantly, Slit2 transfection suppressed the metastasis of HT1080 tumor cells in lungs after intravenous inoculation. Collectively, our study has demonstrated that Slit2 inhibits tumor growth and metastasis of fibrosarcoma and SCC and that its effect on cell cycle and apoptosis signal pathways is an important mechanism for Slit2-mediated tumor suppression.     

Atrial natriuretic peptide in the preterm infant. Lack of correlation with natriuresis and diuresis

We assessed the relation of atrial natriuretic peptide (ANP) to renal function on postnatal day 2 and day 5 in preterm infants. Plasma ANP concentration was measured by radioimmunoassay in two groups of preterm infants: group 1, gestational age less than 30 weeks, n = 10; and group 2, gestational age 30-34 weeks, n = 11. The identity of the immunoreactivity as ANP-28 was confirmed by HPLC. Plasma ANP was significantly higher in group 1 than in group 2 on day 2 and day 5 (p < 0.01) and ANP concentration decreased by day 5 in both groups (group 1, p < 0.01; group 2, p < 0.02). The results showed no correlation between plasma ANP concentration and urinary sodium excretion or creatinine clearance, which may be due to a blunted renal response to ANP, but other factors may be involved also. We conclude that preterm infants are able to release large amounts of ANP, but a high plasma ANP concentration does not correlate directly with renal regulation of sodium and water balance.     

Impact of a medically supervised safer injecting facility on drug dealing and other drug-related crime

North America's first medically supervised safer injecting facility (SIF) recently opened in Vancouver, Canada. One of the concerns prior to the SIF's opening was that the facility might lead to a migration of drug activity and an increase in drug-related crime. Therefore, we examined crime rates in the neighborhood where the SIF is located in the year before versus the year after the SIF opened. No increases were seen with respect to drug trafficking (124 vs. 116) or assaults/robbery (174 vs. 180), although a decline in vehicle break-ins/vehicle theft was observed (302 vs. 227). The SIF was not associated with increased drug trafficking or crimes commonly linked to drug use.     

HIV seroprevalence among participants at a Supervised Injection Facility in Vancouver, Canada: implications for prevention, care and treatment

North America's first government sanctioned medically supervised injection facility (SIF) was opened during September 2003 in Vancouver, Canada. This was in response to a large open public drug scene, high rates of HIV and hepatitis C transmission, fatal drug overdoses, and poor health outcomes among the city's injection drug users. Between December 2003 and April 2005, a representative sample of 1,035 SIF participants were enrolled in a prospective cohort that required completing an interviewer-administered questionnaire and providing a blood sample for HIV testing. HIV infection was detected in 170/1007 (17%) participants and was associated with Aboriginal ethnicity (adjusted Odds Ratio [aOR], 2.70, 95% Confidence Interval [95% CI], 1.84–3.97), a history of borrowing used needles/syringes (aOR, 2.0, 95% CI, 1.37–2.93), previous incarceration (aOR, 1.87, 95% CI, 1.11–3.14), and daily injection cocaine use (aOR, 1.42, 95% CI, 1.00–2.03). The SIF has attracted a large number of marginalized injection drug users and presents an excellent opportunity to enhance HIV prevention through education, the provision of sterile injecting equipment, and a supervised environment to self-inject. In addition, the SIF is an important point of contact for HIV positive individuals who may not be participating in HIV care and treatment.     

曲安奈德辅助玻璃体切割术的应用

目的研究曲安奈德（TA）辅助玻璃体切割手术在临床的应用价值。方法28例（29只眼）于2004年1月～2004年12月行玻璃体切割术，术中注入已过滤的TA悬浮液0．1ml（40mg／m1），以帮助辨认玻璃体后皮质、视网膜前增殖膜、黄斑前膜、内界膜，9例硅油填充，7例C3FR（15％）填充。手术后17例随访6个月以上，11例随访3至4个月。结果所有的病例，经TA注入后，可明显的改善玻璃体后皮质、视网膜前膜、内界膜的辨认情况。糖尿病视网膜病变术后视力提高占61．5％，伴PVR的视网膜脱离术后视力提高占61．3％，黄斑裂孔4例中3例术后视力提高，4例黄斑前膜术后视力均有提高。所有28例均没有出现高眼压。8例伴PVR的视网膜脱离中6例（占75％）视网膜复位，4例黄斑裂孔均关闭，2例糖尿病黄斑水肿手术后明显减轻。结论经过滤的TA可作为玻璃体切割手术中较好的辅助工具，TA悬浮液是呈白色胶样，可粘附于玻璃体皮质、视网膜前膜或内界膜，帮助分辨玻璃体后皮质、视网膜前膜、内界膜，提高手术效率。没有发现与TA有关的副作用。     

Expression of annexin A1 in esophageal and esophagogastric junction adenocarcinomas: association with poor outcome.

PURPOSE: Annexin A1 (ANXA1) is a calcium-binding protein involved in arachidonic acid metabolism and epidermal growth factor receptor tyrosine kinase pathway. ANXA1 has been implicated in early squamous cell carcinogenesis of esophagus and correlates with degree of tumor differentiation. However, the role of ANXA1 in esophageal adenocarcinoma is unclear. Our goal was to evaluate ANXA1 expression and determine its prognostic significance in adenocarcinoma of the esophagus and esophagogastric junction. EXPERIMENTAL DESIGN: This study included 104 consecutive patients with primary resected esophageal and esophagogastric junction adenocarcinomas (11 stage I, 24 stage II, 53 stage III, and 16 stage IV). ANXA1 protein expression in each tumor was assessed by immunohistochemical staining of tissue microarrays. ANAX1 expression level was classified as high (>/=25% of tumor cells with cytoplasmic staining), low (<25% of tumor cells with cytoplasmic staining), or negative; and was correlated with clinicopathologic features and patients' outcomes. RESULTS: High ANXA1 expression was present in 39% (41 of 104) of tumors and was associated with higher pathologic T stage (P = 0.03) and distant metastasis (P = 0.04). High ANXA1 expression correlated with increased recurrence rate (P = 0.004) and decreased overall survival (P = 0.003) in univariate analysis. In multivariate analysis, ANXA1 expression and pN stage significantly correlated with recurrence rate (P = 0.008 and P < 0.001, respectively) and overall survival (P = 0.02 and P < 0.001, respectively) independent of T stage. CONCLUSION: Our results indicate that high ANXA1 expression is frequent in esophageal and esophagogastric junction adenocarcinomas, correlates with more advanced pathologic T stage and the presence of distant metastasis, and is an independent prognostic factor for patient survival.