RNA Interference by Single- and Double-stranded siRNA With a DNA Extension Containing a 3′ Nuclease-resistant Mini-hairpin Structure

Selective gene silencing by RNA interference (RNAi) involves double-stranded small interfering RNA (ds siRNA) composed of single-stranded (ss) guide and passenger RNAs. siRNA is recognized and processed by Ago2 and C3PO, endonucleases of the RNA-induced silencing complex (RISC). RISC cleaves passenger RNA, exposing the guide RNA for base-pairing with its homologous mRNA target. Remarkably, the 3' end of passenger RNA can accommodate a DNA extension of 19-nucleotides without loss of RNAi function. This construct is termed passenger-3'-DNA/ds siRNA and includes a 3'-nuclease-resistant mini-hairpin structure. To test this novel modification further, we have now compared the following constructs: (I) guide-3'-DNA/ds siRNA, (II) passenger-3'-DNA/ds siRNA, (III) guide-3'-DNA/ss siRNA, and (IV) passenger-3'-DNA/ss siRNA. The RNAi target was SIRT1, a cancer-specific survival factor. Constructs I-III each induced selective knock-down of SIRT1 mRNA and protein in both noncancer and cancer cells, accompanied by apoptotic cell death in the cancer cells. Construct IV, which lacks the SIRT1 guide strand, had no effect. Importantly, the 3'-DNA mini-hairpin conferred nuclease resistance to constructs I and II. Resistance required the double-stranded RNA structure since single-stranded guide-3'-DNA/ss siRNA (construct III) was susceptible to serum nucleases with associated loss of RNAi activity. The potential applications of 3'-DNA/siRNA constructs are discussed. Molecular Therapy-Nucleic Acids (2014) 2, e141; doi:10.1038/mtna.2013.68; published online 7 January 2014

Suicide among male road and rail drivers in Australia: a retrospective mortality study

Objectives: This paper aims to describe the epidemiology of suicide among males employed in driving occupations (road and rail) compared to other male occupations in Australia. Methods: Suicide cases among road and rail drivers were extracted from a national dataset of occupationally coded suicide cases for the period 2001 to 2010. Suicide rates per 100 000 were calculated and standardised using the Australian standard population (2001). Incidence rate ratios (IRR) with 95% confidence intervals were calculated using Mantell Haenszel rates and compared to all employed suicide cases. Results: The majority of suicides in this occupational category occurred in truck drivers, followed by road and rail drivers. 98% of these suicides were among males; hence only males were included in further analyses. The age-standardised rate of male suicide among Road and Rail drivers over the period 2001 to 2010 was 22.6 per 100 000 (95% CI 19.2 to 25.9). The IRR of suicide in this occupational group compared to other male occupations was 1.42 (95% CI 1.26 to1.60). Conclusions: Suicide among Road and Rail drivers is higher than in the other male occupations. Suicide prevention initiatives addressing these risk factors, while also providing access to treatment for those at risk, are clearly needed

Identification of LDH-A as a therapeutic target for cancer cell killing via (i) p53/NAD(H)-dependent and (ii) p53 independent pathways

Most cancer cells use aerobic glycolysis to fuel their growth. The enzyme lactate dehydrogenase-A (LDH-A) is key to cancer’s glycolytic phenotype, catalysing the regeneration of nicotinamide adenine dinucleotide (NAD þ ) from reduced nicotinamide adenine dinucleotide (NADH) necessary to sustain glycolysis. As such, LDH-A is a promising target for anticancer therapy. Here we ask if the tumour suppressor p53, a major regulator of cellular metabolism, influences the response of cancer cells to LDH-A suppression. LDH-A knockdown by RNA interference (RNAi) induced cancer cell death in p53 wild-type, mutant and p53-null human cancer cell lines, indicating that endogenous LDH-A promotes cancer cell survival irrespective of cancer cell p53 status. Unexpectedly,however,weuncoveredanovelroleforp53intheregulationofcancercellNADþ anditsreducedformNADH.Thus, LDH-A silencing by RNAi, or its inhibition using a small-molecule inhibitor, resulted in a p53-dependent increase in the cancer cell ratioofNADH:NADþ.Thiseffectwasspecificforp53þ/þ cancercellsandcorrelatedwith(i)reducedactivityofNADþ-dependent deacetylase sirtuin 1 (SIRT1) and (ii) an increase in acetylated p53, a known target of SIRT1 deacetylation activity. In addition, activation of the redox-sensitive anticancer drug EO9 was enhanced selectively in p53 þ / þ cancer cells, attributable to increased activity of NAD(P)H-dependent oxidoreductase NQO1 (NAD(P)H quinone oxidoreductase 1). Suppressing LDH-A increased EO9-inducedDNAdamageinp53þ/þ cancercells,butimportantlyhadnoadditiveeffectinnon-cancercells.Ourresultsidentifya unique strategy by which the NADH/NADþ cellular redox status can be modulated in a cancer-specific, p53-dependent manner and we show that this can impact upon the activity of important NAD(H)-dependent enzymes. To summarise, this work indicates two distinct mechanisms by which suppressing LDH-A could potentially be used to kill cancer cells selectively, (i) through induction of apoptosis, irrespective of cancer cell p53 status and (ii) as a part of a combinatorial approach with redox-sensitive anticancer drugs via a novel p53/NAD(H)-dependent mechanism

Mental Disorders and Communication of Intent to Die in Indigenous Suicide Cases, Queensland, Australia

In comparing Indigenous to non-Indigenous suicide in Australia, this study focussed on the frequency of the association between some psychiatric conditions, such as depression and alcohol abuse, and some aspect of suicidality, in particular communication of suicide intent. Logistic regression was implemented to analyze cases of Indigenous (n = 471) versus non-Indigenous suicides (n = 6,655), using the Queensland Suicide Register as a data source. Compared to non-Indigenous suicides, Indigenous cases had lower odds of being diagnosed with unipolar depression, seeking treatment for psychiatric conditions or leaving a suicide note. Indigenous suicides had greater odds of verbally communicating suicide intent and having a history of alcohol and substance use. The magnitude of these differences is remarkable, underscoring the need for culturally sensitive suicide prevention efforts

Oncogenic viral protein HPV E7 up-regulates the SIRT1 longevity protein in human cervical cancer cells

Senescence is blocked in human cervical keratinocytes infected with high risk human papillomavirus (e.g. HPV type16). Viral oncoproteins HPV E6 and HPV E7 access the cell cycle via cellular p53 and retinoblastoma proteins respectively. Previously we have shown that HPV E7, not HPV E6, is also responsible for cervical cancer cell survival (SiHa cells; HPV type16). We now present evidence that SIRT1, an aging-related NAD-dependent deacetylase, mediates HPV E7 survival function in SiHa cervical cancer cells. Moreover, HPV E7 up-regulates SIRT1 protein when expressed in primary human keratinocytes. Conversely, SIRT1 levels decrease following RNAi-mediated silencing of HPV E7 in SiHa cells. Silencing HPV E6 has no effect on SIRT1 but, as expected, causes marked accumulation of p53 protein accompanied by p53-mediated up-regulation of p21. However, p53 acetylation (K382Ac) was barely detectable. Since p53 is a known SIRT1 substrate we propose that elevated SIRT1 levels (induced by HPV E7) attenuate p53 pro-apoptotic capacity via its de-acetylation. Our discovery that HPV E7 up-regulates SIRT1 links a clinically important oncogenic virus with the multi-functional SIRT1 protein. This link may open the way for a more in-depth understanding of the process of HPV-induced malignant transformation and also of the inter-relationships between aging and cancer

Area-level unemployment and perceived job insecurity: evidence from a longitudinal survey conducted in the Australian working-age population

Research significance: Job insecurity, the subjective individual anticipation of involuntary job loss, negatively affects employees’ health and their engagement. Although the relationship between job insecurity and health has been extensively studied, job insecurity as an ‘exposure’ has received far less attention, with little known about the upstream determinants of job insecurity in particular. This research sought to identify the relationship between self-rated job insecurity and area-level unemployment using a longitudinal, nationally representative study of Australian households. Methods: Mixed-effect multi-level regression models were used to assess the relationship between area-based unemployment rates and self-reported job insecurity using data from a longitudinal, nationally representative survey running since 2001. Interaction terms were included to test the hypotheses that the relationship between area-level unemployment and job insecurity differed between occupational skill-level groups and by employment arrangement. Marginal effects were computed to visually depict differences in job insecurity across areas with different levels of unemployment. Results: Results indicated that areas with the lowest unemployment rates had significantly lower job insecurity (predicted value 2.74; 95% confidence interval (CI) 2.71–2.78, P < 0.001) than areas with higher unemployment (predicted value 2.81; 95% CI 2.79–2.84, P < 0.001). There was a stronger relationship between area-level unemployment and job insecurity among precariously and fixed-term employed workers than permanent workers. Conclusion: These findings demonstrate the independent influences of prevailing economic conditions, individual- and job-level factors on job insecurity. Persons working on a casual basis or on a fixed-term contract in areas with higher levels of unemployment are more susceptible to feelings of job insecurity than those working permanently

Sickness absence and psychosocial job quality: an analysis from a longitudinal survey of working Australians, 2005-2012

Sickness absence is associated with adverse health, organizational, and societal outcomes. Using data from a longitudinal cohort study of working Australians (the Household, Income and Labour Dynamics in Australia (HILDA) Survey), we examined the relationship between changes in individuals' overall psychosocial job quality and variation in sickness absence. The outcome variables were paid sickness absence (yes/no) and number of days of paid sickness absence in the past year (2005-2012). The main exposure variable was psychosocial job quality, measured using a psychosocial job quality index (levels of job control, demands and complexity, insecurity, and perceptions of unfair pay). Analysis was conducted using longitudinal fixed-effects logistic regression models and negative binomial regression models. There was a dose-response relationship between the number of psychosocial job stressors reported by an individual and the odds of paid sickness absence (1 adversity: odds ratio (OR) = 1.26, 95% confidence interval (CI): 1.09, 1.45 (P = 0.002); 2 adversities: OR = 1.28, 95% CI: 1.09, 1.51 (P = 0.002); â‰13 adversities: OR = 1.58, 95% CI: 1.29, 1.94 (P < 0.001)). The negative binomial regression models also indicated that respondents reported a greater number of days of sickness absence in response to worsening psychosocial job quality. These results suggest that workplace interventions aiming to improve the quality of work could help reduce sickness absence

Employment predictors of exit from work among workers with disabilities: a survival analysis from the household income labour dynamics in Australia survey

OBJECTIVES: Across high-income countries, unemployment rates among workers with disabilities are disproportionately high. The aim of this study was to identify characteristics of employment associated with dropping out of work and assess whether these were different for workers with versus without disabilities. METHODS: Using a longitudinal panel study of working Australians (2001 to 2015), the current study estimated Kaplan-Meier curves and Cox proportional hazard regression models to identify predictors of leaving employment, including psychosocial job quality, employment arrangement, and occupational skill level. Effect modification by disability status of the relationship between employment-related factors and exit from the labour market were assessed by including interaction terms and assessing model fit with a likelihood ratio test. Models were adjusted for a range of socio-demographic and health related factors. RESULTS: Compared to those without disability, those with disability had a greater risk of leaving employment (HR 1.26, 95% CI 1.18 to 1.35, p<0.001). Other predictors of exit from work included low-skilled occupation (HR 1.18, 95% CI 1.07 to 1.29, p = 0.001), being in a job with low psychosocial job quality (HR 1.11, 95% CI 1.03 to 1.19, p = 0.007), and casual, labour hire or fixed-term contract employment (HR 1.58, 95% CI 1.48 to 1.69, p<0.001). There was no effect modification by disability status. CONCLUSIONS: More research is needed to understand the experiences of workers with disabilities who stay in and leave employment

Mental health of adolescents:variations by disability and borderline intellectual functioning and disability

Adolescence is a period of elevated stress for many young people, and it is possible that the challenges of adolescence are different for vulnerable groups. We aimed to document the mental health, emotional and behavioral difficulties and suicidal/self-harming behaviors among adolescents with borderline intellectual functioning (BIF) or a disability, compared to those with neither disability nor BIF. Data was drawn from the Longitudinal Study of Australian Children, a nationally representative Australian study. Participants were 2950 adolescents with complete data for Waves 3-6 (years 2008-2014), aged 14-15 years in 2014. Mental health items and self-harming/suicidal thought/behaviors were self-reported. Emotional-behavioral difficulties items came from the Strengths and Difficulties Questionnaire, and were parent-, and adolescent-reported. Results of logistic regression analyses indicate that the emotional-behavioral difficulties of adolescents with either a disability or BIF, was worse than for those with neither disability nor BIF. Additionally, adolescents with a disability reported more symptoms of anxiety and depression, and were more likely to report self-harming/suicidal thoughts and behaviors. Adolescents with BIF or a disability are at higher risk of emotional-behavioral difficulties than those with neither disability nor BIF. There is some evidence that adolescents with a disability are at higher risk of anxiety, self-harming/suicidal thoughts and behaviors than adolescents without a disability