2018 Langley Award for Basic Research on Nicotine and Tobacco: Bringing Precision Medicine to Smoking Cessation

Individual variations in motives for nicotine self-administration in male rats: evidence in support for a precision psychopharmacology

The significant heterogeneity in smoking behavior among smokers, coupled with the inconsistent efficacy of approved smoking cessation therapies, supports the presence of individual variations in the mechanisms underlying smoking. This emphasizes the need to shift from standardized to personalized smoking cessation therapies. However, informed precision medicine demands precision fundamental research. Tobacco smoking is influenced and sustained by diverse psychopharmacological interactions between nicotine and environmental stimuli. In the classical experimental rodent model for studying tobacco dependence, namely intravenous self-administration of nicotine, seeking behavior is reinforced by the combined delivery of nicotine and a discrete cue (nicotine+cue). Whether self-administration behavior is driven by the same psychopharmacological mechanisms across individual rats remains unknown and unexplored. To address this, we employed behavioral pharmacology and unbiased cluster analysis to investigate individual differences in the mechanisms supporting classical intravenous nicotine self-administration (0.04 mg/kg/infusion) in male outbred Sprague-Dawley rats. Our analysis identified two clusters: one subset of rats sought nicotine primarily for its reinforcing effects, while the second subset sought nicotine to enhance the reinforcing effects of the discrete cue. Varenicline (1 mg/kg i.p.) reduced seeking behavior in the former group, whereas it tended to increase in the latter group. Crucially, despite this fundamental qualitative difference revealed by behavioral manipulation, the two clusters exhibited quantitatively identical nicotine+cue self-administration behavior. The traditional application of rodent models to study the reinforcing and addictive effects of nicotine may mask individual variability in the underlying motivational mechanisms. Accounting for this variability could significantly enhance the predictive validity of translational research.

Advancing Biomarkers for Treatment of Smoking and Nicotine Dependence: An Overview

The special issue on Biomarkers of Nicotine and Tobacco Dependence reviews the science for precision treatment of nicotine dependence and future opportunities for research on biomarkers for inclusion in tobacco product cessation and switching clinical trials to advance translation. This overview summarizes the articles contributed to the special issue by leading researcher in field of addiction.

The Use of Biomarkers to Guide Precision Treatment for Tobacco Use

This review summarizes the evidence to date on the development of biomarkers for personalizing the pharmacological treatment of combustible tobacco use. First, the latest evidence on FDA-approved medications is considered, demonstrating that, while these medications offer real benefits, they do not contribute to smoking cessation in approximately two-thirds of cases. Second, the case for using biomarkers to guide tobacco treatment is made based on the potential to increase medication effectiveness and uptake and reduce side effects. Next, the FDA framework of biomarker development is presented along with the state of science on biomarkers for tobacco treatment, including a review of the nicotine metabolite ratio, electroencephalographic event-related potentials, and other biomarkers utilized for risk feedback. We conclude with a discussion of the challenges and opportunities for the translation of biomarkers to guide tobacco treatment and propose priorities for future research.

The relationship between endoplasmic reticulum stress and autophagy in apoptosis of BEAS-2B cells induced by cigarette smoke condensate

Cigarette smoke (CS) is one of the severe risk factors for the development of the pulmonary disease. However, the underlying mechanisms, especially the CS-induced the human bronchial epithelial cells (BEAS-2B) apoptosis related to endoplasmic reticulum stress (ERS) and autophagy, remains to be studied. This study aims to investigate the relationship between ERS and autophagy in apoptosis induced by CS condensate (CSC). BEAS-2B cells were stimulated with 0.02, 0.04 and 0.08 mg/ml CSC for 24 h to detect the ERS, autophagy and apoptosis. Then, ERS and autophagy of BEAS-2B cells were inhibited, respectively, by using 4-PBA and 3-MA, and followed by CSC treatment. The results showed that CSC decreased cell viability, increased cell apoptosis, elevated cleaved-caspase 3/pro-caspase 3 ratio and Bax expressions, but decreased Bcl-2 expressions. The GRP78 and CHOP expressions and LC3-II/LC3-I ratio were dose-dependently increased. The structure of the endoplasmic reticulum was abnormal and the number of autolysosomes was increased in BEAS-2B cells after CSC stimulation. The LC3-II/LC3-I ratio was decreased after ERS inhibition with 4-PBA, but GRP78 and CHOP expressions were enhanced after autophagy inhibition with 3-MA. CSC-induced apoptosis was further increased, Bax expressions and cleaved-caspase 3/pro-caspase 3 ratio were improved, but Bcl-2 expressions were decreased after 3-MA or 4-PBA treatment. In conclusion, the study indicates that ERS may repress apoptosis of BEAS-2B cells induced by CSC via activating autophagy, but autophagy relieves ERS in a negative feedback. This study provides better understanding and experimental support on the underlying mechanisms of pulmonary disease stimulated by CS.

Proof of Concept of a Personalized Genetic Risk Tool to Promote Smoking Cessation: High Acceptability and Reduced Cigarette Smoking

Relatively little is known about the possible effects of personalized genetic risk information on smoking, the leading preventable cause of morbidity and mortality. We examined the acceptability and potential behavior change associated with a personalized genetically informed risk tool (RiskProfile) among current smokers. Current smokers (n = 108) were enrolled in a pre-post study with three visits. At visit 1, participants completed a baseline assessment and genetic testing via 23andMe. Participants' raw genetic data (CHRNA5 variants) and smoking heaviness were used to create a tailored RiskProfile tool that communicated personalized risks of smoking-related diseases and evidence-based recommendations to promote cessation. Participants received their personalized RiskProfile intervention at visit 2, approximately 6 weeks later. Visit 3 involved a telephone-based follow-up assessment 30 days after intervention. Of enrolled participants, 83% were retained across the three visits. Immediately following intervention, acceptability of RiskProfile was high (M = 4.4; SD = 0.6 on scale of 1 to 5); at 30-day follow-up, 89% of participants demonstrated accurate recall of key intervention messages. In the full analysis set of this single-arm trial, cigarettes smoked per day decreased from intervention to 30-day follow-up [11.3 vs. 9.8; difference = 1.5; 95% confidence interval (0.6-2.4); P = 0.001]. A personalized genetically informed risk tool was found to be highly acceptable and associated with a reduction in smoking, although the absence of a control group must be addressed in future research. This study demonstrates proof of concept for translating key basic science findings into a genetically informed risk tool that was used to promote progress toward smoking cessation.Prevention Relevance: This study demonstrates that personal genetic information can be incorporated into a risk feedback tool that was highly acceptable to current smokers and associated with reductions in smoking. These findings may pave the way for effectiveness and implementation research on genetically-informed behavior change interventions to enhance cancer prevention efforts.