Proteasomal degradation of sphingosine kinase 1 and inhibition of dihydroceramide desaturase by the sphingosine kinase inhibitors, SKi or ABC294640, induces growth arrest in androgen-independent LNCaP-AI prostate cancer cells

Sphingosine kinases (two isoforms termed SK1 and SK2) catalyse the formation of the bioactive lipid sphingosine 1-phosphate. We demonstrate here that the SK2 inhibitor, ABC294640 (3-(4-chlorophenyl)-adamantane-1-carboxylic acid (pyridin-4-ylmethyl)amide) or the SK1/SK2 inhibitor, SKi (2-(p-hydroxyanilino)-4-(p-chlorophenyl)thiazole)) induce the proteasomal degradation of SK1a (Mr = 42 kDa) and inhibit DNA synthesis in androgen-independent LNCaP-AI prostate cancer cells. These effects are recapitulated by the dihydroceramide desaturase (Des1) inhibitor, fenretinide. Moreover, SKi or ABC294640 reduce Des1 activity in Jurkat cells and ABC294640 induces the proteasomal degradation of Des1 (Mr = 38 kDa) in LNCaP-AI prostate cancer cells. Furthermore, SKi or ABC294640 or fenretinide increase the expression of the senescence markers, p53 and p21 in LNCaP-AI prostate cancer cells. The siRNA knockdown of SK1 or SK2 failed to increase p53 and p21 expression, but the former did reduce DNA synthesis in LNCaP-AI prostate cancer cells. Moreover, N-acetylcysteine (reactive oxygen species scavenger) blocked the SK inhibitor-induced increase in p21 and p53 expression but had no effect on the proteasomal degradation of SK1a. In addition, siRNA knockdown of Des1 increased p53 expression while a combination of Des1/SK1 siRNA increased the expression of p21. Therefore, Des1 and SK1 participate in regulating LNCaP-AI prostate cancer cell growth and this involves p53/p21-dependent and -independent pathways. Therefore, we propose targeting androgen-independent prostate cancer cells with compounds that affect Des1/SK1 to modulate both de novo and sphingolipid rheostat pathways in order to induce growth arrest

Role of sphingosine 1-phosphate receptors, sphingosine kinases and sphingosine in cancer and inflammation

Sphingosine kinase (there are two isoforms, SK1 and SK2) catalyses the formation of sphingosine 1-phosphate (S1P), a bioactive lipid that can be released from cells to activate a family of G protein-coupled receptors, termed S1P1-5. In addition, S1P can bind to intracellular target proteins, such as HDAC1/2, to induce cell responses. There is increasing evidence of a role for S1P receptors (e.g. S1P4) and SK1 in cancer, where high expression of these proteins in ER negative breast cancer patient tumours is linked with poor prognosis. Indeed, evidence will be presented here to demonstrate that S1P4 is functionally linked with SK1 and the oncogene HER2 (ErbB2) to regulate mitogen-activated protein kinase pathways and growth of breast cancer cells. Although much emphasis is placed on SK1 in terms of involvement in oncogenesis, evidence will also be presented for a role of SK2 in both T-cell and B-cell acute lymphoblastic leukemia. In patient T-ALL lymphoblasts and T-ALL cell lines, we have demonstrated that SK2 inhibitors promote T-ALL cell death via autophagy and induce suppression of c-myc and PI3K/AKT pathways. We will also present evidence demonstrating that certain SK inhibitors promote oxidative stress and protein turnover via proteasomal degradative pathways linked with induction of p53-and p21-induced growth arrest. In addition, the SK1 inhibitor, PF-543 exacerbates disease progression in an experimental autoimmune encephalomyelitis mouse model indicating that SK1 functions in an anti-inflammatory manner. Indeed, sphingosine, which accumulates upon inhibition of SK1 activity, and sphingosine-like compounds promote activation of the inflammasome, which is linked with multiple sclerosis, to stimulate formation of the pro-inflammatory mediator, IL-1β. Such compounds could be exploited to produce antagonists that diminish exaggerated inflammation in disease. The therapeutic potential of modifying the SK-S1P receptor pathway in cancer and inflammation will therefore, be reviewed

A multidimensional model of mothers’ perceptions of parent alcohol socialization and adolescent alcohol misuse.

We assessed a multidimensional model of parent alcohol socialization in which key socialization factors were considered simultaneously to identify combinations of factors that increase or decrease risk for development of adolescent alcohol misuse. Of interest was the interplay between putative risk and protective factors, such as whether the typically detrimental effects on youth drinking of parenting practices tolerant of some adolescent alcohol use are mitigated by an effective overall approach to parenting and parental modeling of modest alcohol use. The sample included 1,530 adolescents and their mothers; adolescents’ mean age was 13.0 (SD = .99) at the initial assessment. Latent profile analysis was conducted of mothers’ reports of their attitude toward teen drinking, alcohol-specific parenting practices, parental alcohol use and problem use, and overall approach to parenting. The profiles were used to predict trajectories of adolescent alcohol misuse from early to middle adolescence. Four profiles were identified: two profiles reflected conservative alcohol-specific parenting practices and two reflected alcohol-tolerant practices, all in the context of other attributes. Alcohol misuse accelerated more rapidly from grade 6 through 10 in the two alcohol-tolerant compared with conservative profiles. Results suggest that maternal tolerance of some youth alcohol use, even in the presence of dimensions of an effective parenting style and low parental alcohol use and problem use, is not an effective strategy for reducing risky adolescent alcohol use

Effect of sphingosine kinase modulators on interleukin-1β release, sphingosine 1-phosphate receptor 1 expression and experimental autoimmune encephalomyelitis : FTY720 analogues and inflammation

Background and Purpose: The sphingosine analogue, FTY720 (Gilenya®) alleviates clinical disease progression in multiple sclerosis. Here we variously assessed the effects of an azide analogue of (S)-FTY720 vinylphosphonate (compound 5; a sphingosine kinase 1 activator), (R)-FTY720 methyl ether (ROMe, a sphingosine kinase 2 inhibitor) and RB-020 (a sphingosine kinase 1 inhibitor and sphingosine kinase 2 substrate) on IL-1beta formation, sphingosine 1-phosphate levels and S1P1 expression. We also assessed the effect of compound 5 and ROMe in an experimental autoimmune encephalomyelitis (EAE) model. Experimental Approach: We measured IL-1beta formation by macrophages, sphingosine 1-phosphate levels and S1P1 expression levels in vitro and clinical score and inflammatory cell infiltration into the spinal cord in vivo. Key Results: Treatment of differentiated U937 macrophages with compound 5, RB-020 or sphingosine (but not ROMe) enhanced IL-1beta release. This data suggests these compounds might be pro-inflammatory in vitro. However, compound 5 or ROMe reduced disease progression and infiltration of inflammatory cells into the spinal cord in EAE and ROMe induced a reduction in CD4+ and CD8+ T-cell levels in the blood (lymphopenia). Indeed, ROMe induced a marked decrease in cell surface S1P1 expression in vitro. Conclusion and Implications: This is the first demonstration that an activator of SK1 (compound 5) and an inhibitor of SK2 (ROMe, which also reduces cell surface S1P1 expression) have an anti-inflammatory action in EAE

cMET inhibitor crizotinib impairs angiogenesis and reduces tumor burden in the C3(1)-Tag model of basal-like breast cancer

Epidemiologic studies have associated obesity with increased risk of the aggressive basal-like breast cancer (BBC) subtype. Hepatocyte growth factor (HGF) signaling through its receptor, cMET, is elevated in obesity and is a pro-tumorigenic pathway strongly associated with BBC. We previously reported that high fat diet (HFD) elevated HGF, cMET, and phospho-cMET in normal mammary gland, with accelerated tumor development, compared to low fat diet (LFD)-fed lean controls in a murine model of BBC. We also showed that weight loss resulted in a significant reversal of HFD-induced effects on latency and elevation of HGF/cMET signaling in normal mammary and cMET in normal mammary and tumors. Here, we sought to inhibit BBC tumor progression in LFD- and HFD-fed C3(1)-Tag BBC mice using a small molecule cMET inhibitor, and began crizotinib treatment (50mg/kg body weight by oral gavage) upon identification of the first palpable tumor. We next investigated if administering crizotinib in a window prior to tumor development would inhibit or delay BBC tumorigenesis. Treatment: Crizotinib significantly reduced mean tumor burden by 27.96 and 37.29%, and mean tumor vascularity by 35.04 and 33.52%, in our LFD- and HFD-fed C3(1)-Tag BBC mice, respectively. Prevention: Crizotinib significantly accelerated primary tumor progression in both diet groups but had no effect on total tumor progression or total tumor burden. In sum, cMET inhibition by crizotinib limited tumor development and microvascular density in basal-like tumor-bearing mice but did not appear to be an effective preventive agent for BBC.Electronic supplementary materialThe online version of this article (doi:10.1186/s40064-016-1920-3) contains supplementary material, which is available to authorized users

Longitudinal Mediators of Relations Between Family Violence and Adolescent Dating Aggression Perpetration: Family Violence and Adolescent Dating Aggression

Few longitudinal studies have examined the pathways through which family violence leads to dating aggression. In the current study the authors used 3 waves of data obtained from 8th- and 9th-grade adolescents (N = 1,965) to examine the hypotheses that the prospective relationship between witnessing family violence and directly experiencing violence and physical dating aggression perpetration is mediated by 3 constructs: (a) normative beliefs about dating aggression (norms), (b) anger dysregulation, and (c) depression. Results from cross-lagged regression models suggest that the relationship between having been hit by an adult and dating aggression is mediated by changes in norms and anger dysregulation, but not depression. No evidence of indirect effects from witnessing family violence to dating aggression was found through any of the proposed mediators. Taken together, the findings suggest that anger dysregulation and normative beliefs are potential targets for dating abuse prevention efforts aimed at youth who have directly experienced violence

Effect of Addition of an Intimate Partner Violence Intervention to a Nurse Home Visitation Program on Maternal Quality of Life: A Randomized Clinical Trial

Importance: Intimate partner violence (IPV) is a public health problem with significant adverse consequences for women and children. Past evaluations of a nurse home visitation program for pregnant women and first-time mothers experiencing social and economic disadvantage have not consistently shown reductions in IPV. Objective: To determine the effect on maternal quality of life of a nurse home visitation program augmented by an IPV intervention, compared with the nurse home visitation program alone. Design, Setting, and Participants: Cluster-based, single-blind, randomized clinical trial at 15 sites in 8 US states (May 2011-May 2015) enrolling 492 socially disadvantaged pregnant women (≥16 years) participating in a 2.5-year nurse home visitation program. Interventions: In augmented program sites (n = 229 participants across 7 sites), nurses received intensive IPV education and delivered an IPV intervention that included a clinical pathway to guide assessment and tailor care focused on safety planning, violence awareness, self-efficacy, and referral to social supports. The standard program (n = 263 participants across 8 sites) included limited questions about violence exposure and information for abused women but no standardized IPV training for nurses. Main Outcomes and Measures: The primary outcome was quality of life (WHOQOL-BREF; range, 0-400; higher score indicates better quality of life) obtained through interviews at baseline and every 6 months until 24 months after delivery. From 17 prespecified secondary outcomes, 7 secondary end points are reported, including scores on the Composite Abuse Scale, SPAN (Startle, Physiological Arousal, Anger, and Numbness), Prime-MD Patient Health Questionnaire, TWEAK (Tolerance/Worry About Drinking/Eye-Opener/Amnesia/C[K]ut Down on Drinking), Drug Abuse Severity Test, and the 12-Item Short-Form Health Survey (physical and mental health), version 2. Results: Among 492 participants enrolled (mean age, 20.4 years), 421 (86%) completed the trial. Quality of life improved from baseline to 24 months in both groups (change in WHOQOL-BREF scores from 299.5 [SD, 54.4] to 308.2 [SD, 52.6] in the augmented program group vs from 293.6 [SD, 56.4] to 316.4 [SD, 57.5] in the standard program group). Based on multilevel growth curve analysis, there was no statistically significant difference between groups (modeled score difference, -4.9 [95% CI, -16.5 to 6.7]). There were no statistically significant differences between study groups in any of the secondary participant end points. There were no adverse events recorded in either group. Conclusions and Relevance: Among pregnant women experiencing social and economic disadvantage and preparing to parent for the first time, augmentation of a nurse home visitation program with a comprehensive IPV intervention, compared with the home visitation program alone, did not significantly improve quality of life at 24 months after delivery. These findings do not support the use of this intervention. Trial Registration: ClinicalTrials.gov Identifier: NCT01372098