Chemoprevention with the metabolism modifying drugs dichloroacetate and metformin in the Li-Fraumeni Syndrome model, Trp53+/- mice

BACKGROUND: While genetic testing for familial cancer has excelled, the prevention options for those carrying high risk alleles have not. Altered bioenergetics is now acknowledged as a hallmark of cancer, and several very safe drugs are available that can target this phentoype. Dichloroacetate (DCA) inactivates pyruvate dehydrogenase kinase, resulting in activation of pyruvate dehydrogenase, reduced lactic acid production and increased mitochondrial activity. Metformin, a type 2 diabetes treatment which activates AMPK, thereby inhibiting mTOR, has unambiguously been demonstrated to reduce the risk of many cancer types in diabetics. We have tested these drugs as chemopreventive agents against the mammary tumours that occur in the BALB/c-Trp53+/- mouse spontaneous tumour model. MATERIALS and METHODS Breast cancer cell lines were examined for cell viability after DCA and/or metformin treatment in vitro (neutral red uptake assay). Four groups of female BALB/c-Trp53+/- mice were given distilled water (n=75), DCA (1.5 g/L in drinking water, ~180 mg/ kg/day, n=53), metformin (0.25 g/L in drinking water, ~30 mg/kg/day, n=61) or DCA +metformin (n=51) from 8 weeks of age, and monitored for tumour development over 78 weeks, and Kaplan-Meier survival analysis was performed. RESULTS In vitro, DCA (1-5 mM) and metformin (30-300 uM), alone or combined, significantly inhibited breast cancer cell growth. In vivo, the overall tumour-free survival curves for BALB/c-Trp53+/- mice were not significantly different between treatment groups, suggesting that metformin does not reduce cancer risk in non-diabetics. However, analysis of mammary tumours alone found that DCA reduced the number and increased their latency (28.0% vs 20.8% of mice with mean latency of 55.0 vs 63.8 weeks, untreated vs DCA respectively), whereas metformin had no effect (26.2% of mice, mean latency 54.7 weeks). DCA appeared to eliminate the early onset mammary tumours (latency <52 weeks, p=0.02), while not affecting the occurrence of longer latency tumours. In contrast, the two drug combination had worse outcomes for tumour development, (35.3% of mice, latency 48.8 weeks, p<0.02 compared to DCA alone). Preliminary western blotting results in MDA-MB-468 breast cancer cells found that DCA could block the activation of AMPK by metformin, indicating the potential for drug interactions.Supported by NHMRC Career Development Award, National Breast Cancer Foundation Novel Concept Award, and Cancer Australia

Dichloroacetate prevents cisplatin-induced nephrotoxicity without compromising cisplatin anticancer properties

Cisplatin is an effective anticancer drug; however, cisplatin use often leads to nephrotoxicity, which limits its clinical effectiveness. In this study, we determined the effect of dichloroacetate, a novel anticancer agent, in a mouse model of cisplatin-induced AKI. Pretreatment with dichloroacetate significantly attenuated the cisplatin-induced increase in BUN and serum creatinine levels, renal tubular apoptosis, and oxidative stress. Additionally, pretreatment with dichloroacetate accelerated tubular regeneration after cisplatin-induced renal damage. Whole transcriptome sequencing revealed that dichloroacetate prevented mitochondrial dysfunction and preserved the energy-generating capacity of the kidneys by preventing the cisplatin-induced downregulation of fatty acid and glucose oxidation, and of genes involved in the Krebs cycle and oxidative phosphorylation. Notably, dichloroacetate did not interfere with the anticancer activity of cisplatin in vivo. These data provide strong evidence that dichloroacetate preserves renal function when used in conjunction with cisplatin

Glutathione Transferase Omega-1 Regulates NLRP3 Inflammasome Activation through NEK7 Deglutathionylation

The NLRP3 inflammasome is a cytosolic complex sensing phagocytosed material and various damage-associated molecular patterns, triggering production of the pro-inflammatory cytokines interleukin-1 beta (IL)-1β and IL-18 and promoting pyroptosis. Here, we characterize glutathione transferase omega 1-1 (GSTO1-1), a constitutive deglutathionylating enzyme, as a regulator of the NLRP3 inflammasome. Using a small molecule inhibitor of GSTO1-1 termed C1-27, endogenous GSTO1-1 knockdown, and GSTO1-1−/− mice, we report that GSTO1-1 is involved in NLRP3 inflammasome activation. Mechanistically, GSTO1-1 deglutathionylates cysteine 253 in NIMA related kinase 7 (NEK7) to promote NLRP3 activation. We therefore identify GSTO1-1 as an NLRP3 inflammasome regulator, which has potential as a drug target to limit NLRP3-mediated inflammation.We would like to acknowledge the following grants: the National Health and Medical Research Council of Australia (NHMRC) is thanked for Project Grant APP1124673 to P.G.B., M.G.C., and L.A.J.O.; Principal Research Fellowship 1117602 to J.B.B.; and NHMRC Project Grant APP1156455 to J.B.B., P.G.B., and M.G.C. The O’Neill laboratory acknowledges the following grant support: European Research Council (ECFP7-ERC-MICROINNATE) and Science Foundation Ireland Investigator Award (SFI 12/IA/1531)

Successful and unsuccessful cannabis quitters: Comparing group characteristics and quitting strategies

<p>Abstract</p> <p>Background</p> <p>In order to improve treatments for cannabis use disorder, a better understanding of factors associated with successful quitting is required.</p> <p>Method</p> <p>This study examined differences between successful (<it>n </it>= 87) and unsuccessful (<it>n </it>= 78) cannabis quitters. Participants completed a questionnaire addressing demographic, mental health, and cannabis-related variables, as well as quitting strategies during their most recent quit attempt.</p> <p>Results</p> <p>Eighteen strategies derived from cognitive behavioral therapy were entered into a principal components analysis. The analysis yielded four components, representing (1) Stimulus Removal, (2) Motivation Enhancement, (3) (lack of) Distraction, and (4) (lack of) Coping. Between groups comparisons showed that unsuccessful quitters scored significantly higher on Motivation Enhancement and (lack of) Coping. This may indicate that unsuccessful quitters focus on the desire to quit, but do not sufficiently plan strategies for coping. Unsuccessful quitters also had significantly more symptoms of depression and stress; less education; lower exposure to formal treatment; higher day-to-day exposure to other cannabis users; and higher cannabis dependence scores.</p> <p>Conclusions</p> <p>The findings suggest that coping, environmental modification, and co-morbid mental health problems may be important factors to emphasize in treatments for cannabis use disorder.</p

GSTO1-1 plays a pro-inflammatory role in models of inflammation, colitis and obesity

Glutathione transferase Omega 1 (GSTO1-1) is an atypical GST reported to play a pro-inflammatory role in response to LPS. Here we show that genetic knockout of Gsto1 alters the response of mice to three distinct inflammatory disease models. GSTO1-1 deficiency ameliorates the inflammatory response stimulated by LPS and attenuates the inflammatory impact of a high fat diet on glucose tolerance and insulin resistance. In contrast, GSTO1-1 deficient mice show a more severe inflammatory response and increased escape of bacteria from the colon into the lymphatic system in a dextran sodium sulfate mediated model of inflammatory bowel disease. These responses are similar to those of TLR4 and MyD88 deficient mice in these models and confirm that GSTO1-1 is critical for a TLR4-like pro-inflammatory response in vivo. In wild-type mice, we show that a small molecule inhibitor that covalently binds in the active site of GSTO1-1 can be used to ameliorate the inflammatory response to LPS. Our findings demonstrate the potential therapeutic utility of GSTO1-1 inhibitors in the modulation of inflammation and suggest their possible application in the treatment of a range of inflammatory conditions.This work was supported by a grant from the Gretel and Gordon Bootes Medical Research Foundation to D.M. and P.B. The National Health and Medical Research Council of Australia (NHMRC) is thanked for Project Grant APP1124673 to PB, MC, LO, AO, and Fellowship support for J.B. (2012–2016 Senior Research Fellowship #1020411). J.B. acknowledges the Australian Federal Government Education Investment Fund Super Science Initiative and the Victorian State Government, Victoria Science Agenda Investment Fund for infrastructure support, and Translating Health Discovery (THD) NCRIS soft infrastructure support through Terapeutic Innovation Australia (TIA)

Health outcomes associated with long-term regular cannabis and tobacco smoking

This study aimed to identify patterns of health concerns associated with long-term use of cannabis and tobacco individually, as well as in combination. We recruited 350 adults aged 40 or over who smoked cannabis but not tobacco (cannabis-only group, n=59), smoked both cannabis and tobacco (cannabis/tobacco group, n=88), smoked tobacco but not cannabis (tobacco-only group, n=80), or used neither substance (control group, n=123). Participants completed a survey addressing substance use, diagnosed medical conditions, health concerns relating to smoking cannabis/tobacco, and general health (measured using the Physical Health Questionnaire and the Short Form 36). Several significant differences were found among the four groups. With regard to diagnosed medical conditions, the three smoking groups reported significantly higher rates of emphysema than did the control group (ps < .001). However, all members of the cannabis-only group diagnosed with emphysema were former regular tobacco smokers. Total general health scores, general health subscales, and items addressing smoking-related health concerns also revealed several significant group differences, and these tended to show worse outcomes for the two tobacco smoking groups. Findings suggest that using tobacco on its own and mixing it with cannabis may lead to worse physical health outcomes than using cannabis alone.7 page(s

Comparison of brief versus extended personalised feedback in an online intervention for cannabis users : short-term findings of a randomised trial

Previous studies have shown brief online self-help interventions to be a useful method of treating cannabis use and related problems; however, no studies have compared the effects of brief versus extended feedback for online brief intervention programs. Objectives: The current study was a two arm randomised trial aimed at testing the short term effectiveness of a brief and extended feedback version of Grassessment, a brief online intervention for cannabis users that provides individualised feedback regarding use, motives, and harms. Methods: Participants (n = 287) reporting at least one symptom of DSM IV cannabis abuse or dependence were recruited using online and offline advertising methods. Participants were randomised to receive either a brief or extended feedback version of the Grassessment program and were required to complete a one month follow up questionnaire. Results: One hundred and ninety four participants completed the one month follow up. Wilcoxon analyses showed a significant decrease in past month quantity and frequency of cannabis use (ps < 0.001; r = − 0.41 and − 0.40 respectively) and lower severity of dependence scores (p = 0.002; r = − 0.31) among those in the brief feedback condition. Participants in the extended feedback group also demonstrated significant decreases in patterns of use (ps < 0.002; r = − 0.39 and − 0.33) but not severity of dependence (p = 0.09; r = 0.18). A Generalized Estimating Equation (GEE) analysis showed no significant interaction between length of feedback received and past month cannabis use frequency (p = 0.78), quantity (p = 0.73), or severity of dependence (p = 0.47). Conclusion: This study adds support for the use of brief online self-complete interventions to reduce cannabis use and related problems in the short term. The findings suggest that in the case of the brief online screening and feedback program Grassessment, extended feedback does not lead to superior outcomes over brief feedback.6 page(s

Applying technology to the treatment of cannabis use disorder : comparing telephone versus Internet delivery using data from two completed trials

Technology-based interventions such as those delivered by telephone or online may assist in removing significant barriers to treatment seeking for cannabis use disorder. Little research, however, has addressed differing technology-based treatments regarding their comparative effectiveness, and how user profiles may affect compliance and treatment satisfaction. This study addressed this issue by examining these factors in online (N = 225) versus telephone (N = 160) delivered interventions for cannabis use, using data obtained from two previously published randomized controlled trials conducted by the current authors. Several differences emerged including stronger treatment effects (medium to large effect sizes in the telephone study versus small effect sizes in the Web study) and lower dropout in the telephone intervention (38% vs. 46%). Additionally, around half of the telephone study participants sought concurrent treatment, compared with 2% of participants in the Web study. Demographics and predictors of treatment engagement, retention and satisfaction also varied between the studies. Findings indicate that both telephone and Web-based treatments can be effective in assisting cannabis users to quit or reduce their use; however, participant characteristics may have important implications for treatment preference and outcome, with those who elect telephonebased treatment experiencing stronger outcomes. Thus, participant preference may shape study populations, adherence, and outcome.7 page(s