High Expression of Delta-Like Ligand 4 Predicts Poor Prognosis After Curative Resection for Pancreatic Cancer

Background

Delta-like ligand 4 (DLL4)-Notch signaling plays a key role in tumor angiogenesis, but its prognostic value in patients with pancreatic ductal adenocarcinoma (PDAC) remains unclear. Our aim was to determine whether high DLL4 expression is correlated with poor prognosis after curative resection for PDAC.

Methods

Surgical specimens obtained from 89 patients with PDAC were immunohistochemically assessed for DLL4 and vascular endothelial growth factor receptor 2 (VEGFR-2) expression. Prognostic significance of DLL4 expression was evaluated by Kaplan–Meier method and Cox regression. The correlations of DLL4 expression with VEGFR-2 expression, tumor stage, and lymph node metastasis were examined by chi-square test and multivariate logistic regression.

Results

There were 38 (42.7%) and 51 patients who showed high and low DLL4 expression, respectively. Survival curves showed that patients with low DLL4 expression had a significantly better survival than those with high DLL4 expression (P < .001). Multivariate survival analysis demonstrated that high DLL4 expression was independently associated with both reduced overall survival (hazard ratio [HR] 2.24; 95% confidence interval [95% CI] 1.14–4.38) and reduced progression-free survival (HR 2.37; 95% CI 1.22–4.60). Multivariate logistic regression analyses showed that high DLL4 expression was independently associated with both advanced tumor stage (odds ratio [OR] 6.84; 95% CI 2.42–9.36) and lymph node metastasis (OR 3.27; 95% CI 1.04–10.34). We also found a positive correlation between DLL4 and VEGFR-2 expression (P < .001).

Conclusions

High DLL4 expression is significantly associated with poor prognosis for surgically resected PDAC, advanced tumor stage, and lymph node metastasis. Application of adjuvant therapy targeting DLL4-Notch signaling may improve prognosis.

     

Hepatic angiomyolipoma: A retrospective study of 25 cases

PURPOSE: We report our experience of diagnosing and treating hepatic angiomyolipoma (HAML), a rare benign mesenchymal tumor. METHODS: We analyzed retrospectively the clinicopathologic, radiological, and operative data of 25 patients who underwent surgery for HAML at our institute between November 2001 and May 2006. RESULTS: Most patients (20/25) were asymptomatic and had normal liver function. Ultrasonography (US) showed a heterogeneous hyperechoic mass in 13 of 23 patients, precontrast computed tomography (CT) showed that all of 12 lesions scanned were hypodense, and magnetic resonance imaging (MRI) showed hypointensity on T1-weighted images and hyperintensity on T2-weighted images in most (5/6) lesions. Marked enhancement in the arterial phase was seen in 10 of 12 lesions on CT scans and in 6 of 6 lesions on MRI scans. All tumors were composed of varying proportions of smooth muscle, adipose tissue, and blood vessels, and showed positive immunohistochemical staining for HMB-45. All patients underwent partial hepatectomy and there was no evidence of recurrence after a median follow-up of 43 months. CONCLUSION: The radiological features of HAML vary according to its histological components. The definitive diagnosis of HAML is challenging and depends on the presence of HMB-45-positive myoid cells. Hepatic angiomyolipoma is treated effectively with surgery and the prognosis is good.     

Inhibitory Effects of Anti-sense PTTG on Malignant Phenotype of Human Ovarian Carcinoma Cell Line SK-OV-3

To construct eukaryotic expression vector expressing full length anti-sense pituitary tumor transforming gene (PTTG) mRNA and observe its blocking effect on the potential invasion of human ovarian carcinoma cell line SK-OV-3. PCR primers containing designed enzyme cut sites were used for cloning full-length PTTG gene fragment, and the resulting PCR product was inserted into the eukaryotic vector pcDNA3. 1 in the antisense direction. The recombinant vector was then transfected into SK-OV-3 by Lipofectamine. The positive cell clone was screened by G418, PTTG and bFGF at protein level expression were detected by Western blot. The biological behavior change of transfection positive cells was observed by colony formation in soft agar assay. Our results showed that SK-OV-3 clones stably expressing full-length recombinant pcDNA3. 1-PTTGas were obtained. The expressions of PTTG and bFGF protein in transfected cells were decreased by 61.5% and 52.3%, respectively as compared with non-transfected ones. The number of colony formation was reduced significantly in transfected cells as compared with empty vector transfected and non-transfected cells. It is concluded that the recombinant vector pcDNA3. 1-PTTGas is a novel tool and provides an alternative anti-sense gene therapy targeted at PTTG in human carcinoma.     

Value of Quantitative Tissue Velocity Imaging in the Detection of Regional Myocardial Function in Dogs with Acute Subendocardial Ischemia

This study evaluated the application of quantitative tissue velocity imaging （QTVI） in assessing regional myocardial systolic and diastolic functions in dogs with acute subendocardial ischemia. Animal models of subendocardial ischemia were established by injecting microspheres （about 300 μm in diameter） into the proximal end of left circumflex coronary artery in 11 hybrid dogs through cannulation. Before and after embolization, two-dimensional echocardiography, QTVI and real-time myocardial contrast echocardiography （RT-MCE） via intravenous infusion of self-made microbubbles,were performed, respectively. The systolic segmental wall thickening and subendocardial myocardial longitudinal velocities of risk segments before and after embolization were compared by using paired t analysis. The regional myocardial video intensity versus contrast time could be fitted to an exponential function： y=A·（1-exp-β·t）, in which the product of A and β provides a measure of myocardial blood flow. RT-MCE showed that subendocardial normalized A·β was decreased markedly from 0.99±0.19 to 0.35±0.11 （P〈0.05） in 28 left ventricular （LV） myocardial segments after embolization, including 6 basal and 9 middle segments of lateral wall （LW）, 8 middle segments of posterior wall （PW） and 5 middle segments of inferior wall （IW）. However, there was no statistically significant difference in subepicardial layer before and after embolization. Accordingly, the ratio of A·β of subendocardial myocardium to subepicardial myocardium in these segments was significantly decreased from 1.10±0.10 to 0.31±0.07 （P〈0.05）. Although the systolic wall thickening did not change 5 min after the embolization in these ischemic segments （29%±3% vs 31%±5%, P〉0.05）, the longitudinal peak systolic velocities （Vs） and early-diastolic peak velocities （Ve） recorded by QTVI were declined significantly （P〈0.05）. Moreover, the subendocardial velocity curves during isovolumic relaxation predominant     

Increased Expression of PI-3K in Asthmatic Rat T Lymphocytes

In order to explore the expression of PI-3K in T lymphocytes of asthmatic rats and the relationship between PI-3K and activation of T lymphocytes, 24 Wistar rats were randomly divided into 4 groups: normal control group, asthmatic one-week group, asthmatic two-week group and asth-matic four-week group. T cells were purified from blood of each rat and the expression of PI-3K was observed by immunocytochemical fluorescence staining, the semiquantitative fluorescence intensity was measured by HPIAS-2000 analytic software, and the expression of IL-4 in supernatants was de-tected by ELISA. The results showed that the fluorescence intensity of T lymphocytes in asthmatic groups was significantly higher than that in normal control (P<0.001), indicating that the expression of PI-3K in T lymphocytes of asthmatic rats was significantly higher than that in those of normal controls, and the difference between acute and chronic stage asthmatic groups was significant (P<0.05). The expression levels of IL-4 protein in supernatants of asthmatic T lymphocytes were sig-nificantly higher than those in the normal controls (P<0.05). There was a significant positive correla-tion between the expression of PI-3K in T lymphocytes and the IL-4 protein expression in super-natants (r=0.583, P<0.01). It was suggested that PI-3K signal pathway may participate in the proc-esses of activation and other cytological effects of asthmatic T lymphocytes, thus may play an impor-tant roles in the pathogenesis of asthma.     

Inhibitory activity of nuclear factor-κB potentiates cisplatin-induced apoptosis in A549 cells

Whether inhibiting the activity of nuclear factor （NF）-κB potentiates cisplatin-induced apoptosis in non-small cell lung cell line A549 cells was investigated. The recombinant plasmid pcDNA3.1（＋）/IκBα expressing IκBα was constructed. The in vitro cultured A549 cells were transfected with pcDNA3.1 （＋）/IκBα alone, or pcDNA3.1（＋）/IκBα combined with cisplatin. The mitochondrial membrane potential （△ψm） was determined by rhodamine 123, the activity of caspase-3 was tested by colorimetric assay, and cell apoptosis was detected by flow cytometry with the annexin V/propidium iodide assay. The results showed that the activity of NF-κB in A549 cells was inhibited by transfecting pcDNA3.1（＋）/IκBα. Transfection of pcDNA3.1（＋）/IκBα alone did not promote apoptosis. Treatment of cisplatin alone had a little effect on cell apoptosis. Transfection of pcDNA3.1（＋）/IκBα combined with cisplatin treatment significantly induced apoptosis of A549 ceils. It was concluded that inhibiting the activity of NF-κB potentiated cisplatin-induced apoptosis of A549 cells.