Computer-based identification of a novel LIMK1/2 inhibitor that synergizes with salirasib to destabilize the actin cytoskeleton

Neurofibromin regulates cell motility via three distinct GTPase pathways acting through two different domains, the Ras GTPase-activating protein-related domain (GRD) and the pre-GRD domain. First, the GRD domain inhibits Ras-dependent changes in cell motility through the mitogen activated protein cascade. Second, it also regulates Rho-dependent (Ras-independent) changes by activating LIM kinase 2 (LIMK2), an enzyme that phosphorylates and inactivates cofilin (an actin-depolymerizing factor). Third, the pre-GRD domain acts through the Rac1 GTPase, that activate the P21 activated kinase 1 (PAK1)-LIMK1-cofilin pathway. We employed molecular modeling to identify a novel inhibitor of LIMK1/2. The active sites of an ephrin-A receptor (EphA3) and LIMK2 showed marked similarity (60%). On testing a known inhibitor of EphA3, we found that it fits to the LIMK1/2-ATP binding site and to the latter's substrate-binding pockets. We identified a similar compound, T56-LIMKi, and found that it inhibits LIMK1/2 kinase activities. It blocked the phosphorylation of cofilin which led to actin severance and inhibition of tumor cell migration, tumor cell growth, and anchorage-independent colony formation in soft agar. Because modulation of LIMK by neurofibromin is not affected by the Ras inhibitor Salirasib, we examined the combined effect of Salirasib and T56-LIMKi each of which can affect cell motility by a distinct pathway. We found that their combined action on cell proliferation and stress-fiber formation in neurofibromin-deficient cells was synergistic. We suggest that this drug combination may be developed for treatment of neurofibromatosis and cancer.     

Galectin-1 binds oncogenic H-Ras to mediate Ras membrane anchorage and cell transformation.

Ras genes, frequently mutated in human tumors, promote malignant transformation. Ras transformation requires membrane anchorage, which is promoted by Ras farnesylcysteine carboxymethylester and by a second signal. Previously we showed that the farnesylcysteine mimetic, farnesylthiosalicylic acid (FTS) disrupts Ras membrane anchorage. To understand how this disruption contributes to inhibition of cell transformation we searched for new Ras-interacting proteins and identified galectin-1, a lectin implicated in human tumors, as a selective binding partner of oncogenic H-Ras(12V). The observed size of H-Ras(12V)-galectin-1 complex, which is equal to the sum of the molecular weights of Ras and galectin-1 indicates a direct binding interaction between the two proteins. FTS disrupted H-Ras(12V)-galectin-1 interactions. Overexpression of galectin-1 increased membrane-associated Ras, Ras-GTP, and active ERK resulting in cell transformation, which was blocked by dominant negative Ras. Galectin-1 antisense RNA inhibited transformation by H-Ras(12V) and abolished membrane anchorage of green fluorescent protein (GFP)-H-Ras(12V) but not of GFP-H-Ras wild-type (wt), GFP-K-Ras(12V), or GFP-N-Ras(13V). H-Ras(12V)-galectin-1 interactions establish an essential link between two proteins associated with cell transformation and human malignancies that can be exploited to selectively target oncogenic Ras proteins.     

Suicide Risk Among Holocaust Survivors Following Psychiatric Hospitalizations: A Historic Cohort Study

The association between Holocaust experience, suicide, and psychiatric hospitalization has not been unequivocally established. The aim of this study was to determine the risk of suicide among 3 Jewish groups with past or current psychiatric hospitalizations: Holocaust survivors (HS), survivors of pre-Holocaust persecution (early HS), and a comparison group of similar European background who did not experience Holocaust persecution. In a retrospective cohort study based on the Israel National Psychiatric Case Register (NPCR) and the database of causes of death, all suicides in the years 1981–2009 were found for HS (n?=?16,406), early HS (n?=?1,212) and a comparison group (n?=?4,286). Age adjusted suicide rates were calculated for the 3 groups and a logistic regression model was built to assess the suicide risk, controlling for demographic and clinical variables. The number of completed suicides in the study period was: HS—233 (1.4%), early HS—34 (2.8%), and the comparison group—64 (1.5%). Age adjusted rates were 106.7 (95% CI 93.0–120.5) per 100,000 person-years for HS, 231.0 (95% CI 157.0–327.9) for early HS and 150.7 (95% CI 113.2–196.6) for comparisons. The regression models showed significantly higher risk for the early HS versus comparisons (multivariate model adjusted OR?=?1.68, 95% CI 1.09–2.60), but not for the HS versus comparisons. These results may indicate higher resilience among the survivors of maximal adversity compared to others who experienced lesser persecution.     

Composite Fiber Structures with Antiproliferative Agents Exhibit Advantageous Drug Delivery and Cell Growth Inhibition In Vitro

Composite core/shell fiber structures loaded with the antiproliferative drugs paclitaxel or farnesylthiosalicylate (FTS) were developed and studied. The latter is a specific nontoxic Ras inhibitor with a mild hydrophobic nature, which can also be used for local cancer treatment and stent applications. The fibers were composed of a dense polyglyconate core and a porous drug-loaded poly(d,l-lactic-glycolic acid) shell, prepared using freeze drying of inverted emulsions. Our study focused on the release profile of the antiproliferative drugs from the fibers, the shell morphology and its degradation and erosion. The postfabrication antiproliferative effect of the drugs was tested in a cell culture. The process parameters were found to affect the drug-release profile via two routes: (1) direct, through water uptake and swelling of the structure leading to FTS release, or through degradation of the host polymer leading to paclitaxel release at a later stage; (2) indirect effect of the microstructure on the release profile. The fabrication process did not reduce the pharmacological activity of either paclitaxel or FTS. FTS-eluting composite fibers proved to effectively induce growth inhibition or cell death by a gradient effect and dose-dependent manner. The combined effect of the targeted mechanism of FTS as a Ras inhibitor together with the localized and controlled release characteristics of the fiber is an advantageous antiproliferative quality. It is therefore suggested that our drug-eluting fibers may be used in biomedical applications that require short release (restenosis) or prolonged release (cancer therapy).     

Alcohol dependence symptoms and alcohol dehydrogenase 2 polymorphism: Israeli Ashkenazis,Sephardics, and recent Russian immigrants

BACKGROUND: Jews have lower rates of alcohol-related problems than other Caucasians. The ADH2*2 allele of the alcohol dehydrogenase 2 (ADH2 ) gene protects against alcoholism in Asians and is found in approximately 20% of Jews. We studied the relationship of ADH2*2 to DSM-IV dependence severity in a random community sample of Israeli Ashkenazis, recent Russian immigrants (also Ashkenazis), and Sephardics. METHODS: Subjects participated in a structured interview that included highly reliable questions on DSM-IV alcohol dependence symptoms. ADH2 genotype was determined for 68 subjects. RESULTS: Recent Russian immigrants had more past and lifetime DSM-IV dependence symptoms. Sephardics had a higher prevalence of ADH2*2 than Ashkenazis. Controlling for group and other potentially confounding factors, ADH2*2 was associated with a lower lifetime DSM-IV alcohol dependence severity, although this differed somewhat within groups. CONCLUSIONS: ADH2*2 protects against dependence severity in Jewish samples. Future work in larger samples should address genetic and environmental factors that affect the relationship of ADH2*2 to alcohol consumption and dependence.     

Circulating Endothelial Progenitor Cells,Th1/Th2/Th17-Related Cytokines,and Endothelial Dysfunction in Resistant Hypertension

IntroductionA possible link between chronic vascular inflammation and arterial hypertension is now an object of intensive studies.ObjectiveTo compare Th1/Th2/Th17 cells-related cytokines, circulating endothelial progenitor cells (EPC), and endothelial function in subjects with resistant arterial hypertension (RAH) and controlled arterial hypertension (CAH).MethodsBlood pressure was measured by electronic sphygmomanometer. EPC were identified as CD34 +/ CD133 +/kinase insert domain receptor (KDR) + cells by flow cytometry. Th1/Th2/Th17 cells-related cytokines were identified using the Human Th1/Th2/Th17 Cytokines MultiAnalyte ELISArray Kit. Endothelium-dependent (FMD) vasodilatation of brachial artery was measured by Doppler ultrasound scanning.ResultsRAH group (n = 20) and CAH group (n = 20) and 17 healthy individuals (control group) were recruited. In the RAH group, lower blood levels of EPC number (42.4 ± 16.7 cells/mL) and EPC% (0.19 ± 0.08%) were observed than in the CAH group (93.1 ± 88.7 cells/mL; P = 0.017; 0.27 ± 0.17; P = 0.036) and control group (68.5 ± 63.6 cells/mL; P < 0.001; 0.28 ± 0.17%; P = 0.003), respectively. Plasma transforming growth factor-β1 levels were significantly higher in the RAH group (1767 ± 364 pg/mL) than in the CAH group (1292 ± 349; P < 0.001) and in control group (1203 ± 419 pg/mL; P < 0.001). In the RAH group, statistically significant negative correlation was observed between systolic blood pressure and EPC% (r = –0.72, P < 0.01). FMD in the RAH group was significantly lower (5.5 ± 0.8%) than in the CAH group (9.2 ± 1.4; P < 0.001) and in healthy controls (10.1 ± 1.1%; P < 0.001).ConclusionsRAH is characterized by reduced circulating EPC, substantial endothelial dysfunction, and increased plasma transforming growth factor-β1 levels.     

Long-term follow-up and factors influencing success of silastic ring vertical gastroplasty

BACKGROUND: Careful selection of patients for the operation plays a major role in long-term results of silastic ring vertical gastroplasty. The objective of the current study is to identify predictive factors for the objective (excess weight loss) and subjective (satisfaction) success of silastic ring vertical gastroplasty (SRVG) for morbid obesity. METHODS: Design: Retrospective cohort study. Setting: University hospital. Subjects: 300 patients of 450 who were operated on between 1984 and 1997. Follow-up time was 4.4 +/- 2.3 years. Intervention: SRVG. Statistical Methods: Correlations, multi-linear regression model. RESULTS: Average BMI (body mass index) loss: 13.6 +/- 7.4 kg/m(2), average excess weight loss was 67.4 +/- 33.0%. Satisfaction rate: 81.3%. Correlation was found between objective parameters of successes and the satisfaction of the patient (p < 0.001). Excess weight loss was correlated to younger age (p < 0.005), pre-operative weight and BMI (p < 0.005, p < 0.01, respectively), and shorter follow-up (p < 0.001). Multiple linear regression model revealed that age and preoperative weight were independent variables and correlated to the excess weight loss after SRVG (R(2) = 0.303, p < 0.01; R(2) = 0.026, p < 0.05). Social support was correlated to satisfaction (p < 0.05). CONCLUSIONS: SRVG is an operation with high rates of objective and subjective success rate. Younger and heavier subjects will mostly enjoy SRVG in terms of excess weight loss. Patients who have social support have the most satisfactory emotional outcome.     

Injury inequalities: morbidity and mortality of 0-17 year olds in Israel

BACKGROUND: To determine whether there are inequalities in the incidence of fatal and non-fatal unintentional injuries among Jewish and Arab children in Israel. METHODS: A nationwide random sample of injured children aged 0-17 attending emergency rooms (ER) during one year was selected (n = 11 058). The number of cases was weighted to 365 days and rates and odds ratios (OR) were calculated. Logistic regression was performed to study the OR of hospitalization in the total population and among Jews and Arabs controlling for independent variables. RESULTS: The incidence of ER admissions among the Jews was 752.6/10 000 (95% CI: 738.1-767.1), 1.5 times higher than among the Arabs (492.8/10 000, 95% CI: 472.8-512.8). However, the rate of hospitalization was 1.1 times higher among Arabs than among Jews and the mortality rate was 3.2 times higher among Arabs than among Jews. CONCLUSIONS: The differences in injury rates for fatal and non-fatal injuries may be due to differences in the severity of injuries or in the use of services by the two populations. A study is underway to elucidate this point.