Anoikis disruption of focal adhesion-Akt signaling impairs renal cell carcinoma

Background

Quinazoline-based α1-adrenoceptor antagonists suppress tumor growth by inducing apoptosis via an α1-adrenoceptor-independent action. Anoikis is a unique mode of apoptosis consequential to insufficient cell-matrix interactions.

Objective

This study investigated the apoptotic effect of novel quinazoline-based compounds on human renal cancer cells.

Design, setting, and participants

Two cell lines were used: renal cell carcinoma (RCC) 786-0, harboring a von Hippel-Lindau (VHL) tumor-suppressor gene mutation with a highly angiogenic phenotype, and Caki cells (no VHL mutation).

Measurements

The lead compound DZ-50 (10 μM) led to significant inhibition of tumor-cell adhesion, migration, and invasion at a lower dose than doxazosin (25 μM) in both RCC lines.

Results and limitations

Doxazosin induced death-receptor-mediated apoptosis, while DZ-50 led to anoikis via targeting of the focal adhesion complex and AKT signaling that subsequently increased RCC susceptibility to caspase-8-mediated apoptosis. Both quinazoline compounds, doxazosin and DZ-50, significantly reduced RCC metastatic potential in vivo.

Conclusions

Quinazoline-based drugs trigger anoikis in RCC by targeting the focal adhesion survival signaling. This potent antitumor action against human RCC suggests a novel quinazoline-based therapy targeting renal cancer.     

The role of nitric oxide in the mechanical repression of RANKL in bone stromal cells

Both mechanical loading and nitric oxide (NO) have positive influences on bone mass. NO production is induced by mechanical strain via upregulation of eNOS mRNA and protein, the predominant NOS in adult bone. At the same time, strain causes decreased expression of RANKL, a factor critical for osteoclastogenesis. In this study, we harvested primary stromal cells from wild-type (WT) and eNOS(-/-) mice to test whether induction of NO by mechanical strain was necessary for transducing mechanical inhibition of RANKL. We found that strain inhibition of RANKL expression was prevented by NOS inhibitors (L-NAME and L-NMMA) in WT stromal cells. Surprisingly, stromal cells from eNOS(-/-) mice showed significant mechanical repression of RANKL expression (p<0.05). Mechanical strain still increased NO production in the absence of eNOS, and was abolished by SMTC, a specific nNOS inhibitor. nNOS mRNA and protein expression were increased by strain in eNOS(-/-) but not in WT cells, revealing that nNOS was mechanically sensitive. When NO synthesis was blocked with either SMTC or siRNA targeting nNOS in eNOS(-/-) cells however, strain still was able to suppress RANKL expression by 34%. This indicated that strain suppression of RANKL can also occur through non-NO dependent pathways. While our results confirm the importance of NO in the mechanical control of skeletal remodeling, they also suggest alternative signaling pathways by which mechanical force can produce anti-catabolic effects on the skeleton.     

Esophageal Stenting and Radiotherapy: A Multimodal Approach for the Palliation of Symptomatic Malignant Dysphagia

Background

Esophageal stents provide immediate palliation of malignant dysphagia; however, radiotherapy (RT) is a superior long-term option. We review the outcomes of combined esophageal stenting and RT for patients with malignant dysphagia.

Methods

We retrospectively reviewed patients with esophageal stents placed for palliation of malignant dysphagia from esophageal stricture, esophageal extrinsic compression, or malignant tracheoesophageal fistula (TEF). We excluded patients with radiation-induced TEF in the absence of tumor. We analyzed and compared outcomes between patients with no RT, RT before stent placement, and RT after stent placement.

Results

We placed stents in 45 patients for esophageal stricture from esophageal cancer (n?=?30; 66.7?%), malignant TEF (n?=?8; 17.7?%), and esophageal compression from airway, mediastinal, or metastatic malignancies (n?=?7; 15.6?%). Twenty patients (44.4?%) had no RT; 25 patients had RT before stent placement (n?=?16; 35.6?%), RT after stent placement (n?=?8; 17.8?%), or both (n?=?1; 2.2?%). Median follow-up was 30?days. Complications requiring stent revision were similar with or without RT. Subjective symptom relief was achieved in 68.9?% of all patients, with no differences noted between groups (p?=?0.99). The 30-day mortality was 15.6?%. Patients with RT after stent placement had a longer median survival compared to those without RT (98 vs. 38?days).

Conclusions

Esophageal stent placement with RT is a safe approach for malignant dysphagia.     

Modeling prostate cancer in mice: limitations and opportunities

The complex dynamics of the tumor microenvironment and prostate cancer heterogeneity have confounded efforts to establish suitable preclinical mouse models to represent human cancer progression from early proliferative phenotypes to aggressive, androgen-independent, and invasive metastatic tumors. Current models have been successful in capitulating individual characteristics of the aggressive tumors. However, none of these models comprehensively mimics human cancer progression, establishing the challenge in their exploitation to study human disease. The ability to tailor phenotypic outcomes in mice by compounding mutations to target specific molecular pathways provides a powerful tool toward disruption of signaling pathways contributing to the initiation and progression of castration-resistant prostate cancer. Each model is characterized by unique features contributing to the understanding of prostate tumorigenesis, as well as limitations challenging our knowledge of the mechanisms of cancer development and progression. Emerging strategies utilize genomic manipulation technology to circumvent these limitations toward the formulation of attractive, physiologically relevant models of prostate cancer progression to advanced disease. This review discusses the current value of the widely used and well-characterized mouse models of prostate cancer progression to metastasis, as well as the opportunities begging exploitation for the development of new models for testing the antitumor efficacy of therapeutic strategies and identifying new biomarkers of disease progression.     

Vascular endothelial cell apoptosis induced by anti-donor non-MHC antibodies: a possible injury pathway contributing to chronic allograft rejection.

BACKGROUND: Non-major histocompatibility complex (non-MHC) alloantibodies may play a pathogenic role in chronic rejection but remain poorly characterized. METHODS: The kinetics of alloantibody production and the mechanism by which non-MHC alloantibodies cause graft injury were investigated in a Lewis-to-Fischer 344 (LEW-to-F344) rat model of cardiac transplantation. RESULTS: Flow cytometry detected that all the F344 recipients of LEW allografts produced anti-donor immunoglobulin G (IgG) antibodies reactive with LEW lymphocytes and endothelial cells. A sub-group of recipients that rejected their grafts in 30 to 60 days exhibited markedly increased levels of anti-donor IgG antibodies (n = 6, mean fluorescence intensity [MFI]:23.85 +/- 2.7) than recipients with long-surviving allografts (n = 4, MFI:11.23 +/- 0.81; p = 0.00058). Passive transfer of anti-donor sera induced chronic rejection of LEW heart allografts in an immune non-responsiveness model of F344 rats induced by intrathymic inoculation of donor-specific lymphocytes. Immunoglobulin G antibodies purified from the anti-LEW sera exhibited complement-dependent cytotoxicity against LEW vascular endothelial cells in flow-cytometric cytotoxicity assay. The targeted endothelial cells displayed early (annexin V+) and late (TUNEL+) evidence for programmed cell death. Western blot analysis of poly (ADP-ribose) polymerase (PARP) demonstrated that the 25-kD PARP-cleavage fragment was present at the lysates of the vascular endothelial cells treated with anti-donor IgG antibodies, indicating apoptosis-associated caspase activity in these cells. In situ teminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL) staining demonstrated that vascular endothelial cell apoptosis was consistently present in all LEW heart allografts with chronic rejection. CONCLUSIONS: Non-MHC alloantibodies are pathogenic and capable of causing chronic graft injury through an antibody-induced cell apoptosis mechanism. The results emphasize the importance of non-MHC antibodies as a common predisposing factor in the development of chronic rejection.     

A preliminary study on electromyographic analysis of the paraspinal musculature in idiopathic scoliosis

The paraspinal muscles have been implicated as a major causative factor in the progression of idiopathic scoliosis. Therefore, the objectives of this preliminary study were to measure the electromyographic activity (EMG) of the paraspinal muscles to determine its relationship to progression of the scoliotic curve. Idiopathic scoliotic patients were selected and identified afterwards on curve progression. The EMG activity on both sides of the spine was measured in a set of standardized postures using bipolar surface electrodes at the apex and two end vertebrae of the scoliotic curve. An EMG ratio involving measurements of the EMG activity on the convex and concave sides of the scoliotic curve was used to evaluate the paraspinal muscles. Enhanced EMG ratios at the apex of the scoliotic curve were found in both groups during sitting and standing. The most interesting finding was that children with progression of the curve also showed enhanced EMG ratios at the lower end vertebra of the curve. The EMG ratios between the groups were significantly different from each other at the apex and end vertebrae for several test conditions. Overlap in the EMG-ratio ranges made differentiation difficult for prediction of the progression of the individual scoliosis patient. However, the EMG ratio at the lower end vertebra of the scoliotic curve is significantly higher than 1 in all test conditions in the group of children with subsequent progression of the curve, whereas it is always normal in the non-progressive group. Therefore, EMG of the paraspinal muscles might be of value for prediction of progression in idiopathic scoliosis.     

Preoperative Fasting of 2 Hours Minimizes Insulin Resistance and Organic Response to Trauma After Video-Cholecystectomy: A Randomized,Controlled, Clinical Trial

Background  Studies showing the improvement of insulin sensitivity by reducing the term of preoperative fasting are mostly done in patients undergoing major operations. More information about the role of shortened preoperative fasting in perioperative metabolism is needed for such elective minor/moderate abdominal procedures as laparoscopic cholecystectomy. We investigated the influence of a carbohydrate-rich drink given 2 h before laparoscopic cholecystectomy on insulin resistance and the metabolic response to trauma. Methods  A group of 21 female candidates (18–65 years old) for elective laparoscopic cholecystectomy were randomized to either an 8 h fasting group (control group: n = 10) or to a group receiving 200 ml of a carbohydrate beverage containing 12.5% (25 g, 50 kcal per 100 ml and approximately 285 mOsm) of maltodextrine 2 h before operation (CHO group: n = 11). Blood samples for various biochemical assays were collected both at induction of anesthesia and after the 10th postoperative hour. Insulin resistance was assessed by the HOMA-IR equation (Insulin (μU/ml) × blood glucose (mg/dl)/405). Results  There were no postoperative complications. Seventy percent (7/10) of the controls and 27.3% (3/11) of the CHO group experienced at least one episode of vomiting (RR = 2.42, 95% Confidence Interval [CI] = 0.88–6.68; P = 0.08). Biochemical analysis showed that serum glucose (P < 0.01), insulin (P < 0.01), lactate/pyruvate ratio (P = 0.03), and triglycerides (P < 0.01) for the control group were higher than for the CHO group. The value of HOMA-IR was significantly greater (P = 0.03) in the conventionally fasted patients than in the CHO group. Conclusions  Abbreviation of the period of preoperative fasting and administration of a carbohydrate beverage diminishes insulin resistance and the organic response to trauma.     

How long should you wait for a chest radiograph after placing a chest tube on water seal? A prospective study

OBJECTIVE: The purpose of this study was to determine the optimal time interval for identifying a pneumothorax (PTX) on chest radiograph (CXR) after placing a chest tube on water seal. METHODS: One hundred nineteen chest tubes were placed on water seal according to a prospective, observational study protocol. After water seal, both an early (3.1 +/- 2.1 hours) and a late (17.6 +/- 8.0 hours) CXR was obtained. RESULTS: Thirty-one patients had a PTX on follow-up CXRs. There were 22 early and 9 late PTXs identified. Three patients in the early group had a clinically significant PTX or an increase in the size of PTX on follow-up CXR. None of the patients in the late group had a clinically significant PTX (any worsening of their PTX) or required further intervention. CONCLUSION: A normal chest radiograph obtained 3 hours after placing a chest tube on water seal effectively excludes development of a clinically significant pneumothorax.