Abstract 748: Impact of oral supplementation of sulforaphane for 12 months on lung cancer-related gene expression in former smokers at high risk for lung cancer: Results from a randomized placebo-controlled phase II clinical trial

Abstract

Abstract Introduction: Higher consumption of dietary sulforaphane (SFN), a phytochemical found in many cruciferous vegetables, has been shown to be associated with lower risk of lung cancer (LC). SF activates the NRF2-pathway, which initiates cellular detoxification, antioxidant, and anti-inflammatory responses. To date, no chemoprevention trial for LC has examined the impact of SFN on LC-related gene expression (GE) as an endpoint in nasal and bronchial tissue. The objective of our study was to examine whether oral intake of SF for 12 months impacts the GE of previously identified LC- and premalignant lesions (PML)-related genes in bronchial and nasal brushing samples. Methods: A randomized, placebo-controlled clinical trial (NCT03232138) was conducted in former smokers with ≥ 30 pack-years and quitting smoking for 1-10 years in Western Pennsylvania, USA. Forty-three subjects were randomly assigned to the SFN treatment (n = 21) or placebo group (n = 22) in 2018-2022. Each participant was instructed to take 4 Avmacol® or identical placebo capsules BID for 12 months. Each Avmacol® capsule contained 15 mg of glucoraphanin, which yielded a daily internal dose of 120 μmol SFN. Nasal swabs and bronchial brushings were obtained at baseline and after 12 months. Among the 37 participants who completed the study, RNA was extracted from their nasal swabs and bronchial brushings. We constructed single sample gene signature scores (GSS) using the GSVA algorithm for the following: 1) the NRF2-pathway, 2) genes associated with LC risk in bronchial biopsies, and 3) genes associated with PML. The genes in these sets were stratified by their up- or down-regulation in LC or PML. We evaluated the association between the interaction of SFN supplementation over time (pre-/post-treatment) on GSS using linear mixed models, adjusted for the fixed effects of age at baseline, RNA integrity number (RIN), packyears of smoking, and random effect of participant. Results: GE data was available for 31 participant pairs with bronchial and/or nasal samples. Within nasal tissue, SFN treatment increased both the GSSs of the NRF2-pathway (p=0.0089) and the downregulated LC-risk genes (p=0.0047), and decreased the upregulated LC-risk genes (p=0.012) over time, whereas SFN had no significant impact on GSSs of the NRF2-pathway and LC-risk genes in the bronchial tissue. No association between SFN treatment over time and the PML-related GSS was observed in nasal or bronchial tissue. Conclusion: Our initial analysis indicates that SFN treatment over 12 months impacted LC-associated GE in nasal tissue but not in bronchial tissue from former smokers. The discrepancy results may be due to small sample size and additional studies are warranted to confirm if SFN has direct impact on LC-risk related genes in bronchial tissue (NIH grant No. R01CA213123). Citation Format: Kathryn Demanelis, Avrum Spira, Yohana Kefella, Renwei Wang, Jennifer Adams-Haduch, Thomas W. Kensler, Jennifer E. Beane, David O. Wilson, Jian-Min Yuan. Impact of oral supplementation of sulforaphane for 12 months on lung cancer-related gene expression in former smokers at high risk for lung cancer: Results from a randomized placebo-controlled phase II clinical trial [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 748.