Abstract CT105: Validation of a tobacco smoke exposure gene expression signature and exploration of intraoral metabolite profiles following administration of a strawberry functional confection in smokers and nonsmokers
Authors: Ahn-Jarvis Jennifer H. , Knobloch Thomas J. , Oghumu Steve , Reidl Ken M. , Brock Guy , Clinton Steven K. , Vodovotz Yael , Schwartz Steven J. , Weghorst Christopher M. 
Published: July 2017

Dietary administration of whole strawberries has demonstrated great potential as a strategy for oral and esophageal cancer prevention in preclinical trials. We hypothesize that following consumption of a novel confection containing strawberries (i) gene expression profiles in oral mucosa will be modulated in a manner that favor anti-cancer activities, and (ii) unique intraoral metabolites will segregate smokers and nonsmokers. A 6-week randomized, placebo-controlled, Phase I crossover trial using functional confections delivering 24g/day of freeze-dried whole ripe strawberries was examined in smoking and nonsmoking men and women.

Objectives

Validate an annotated targeted oral epithelial gene expression profile in smokers and nonsmokers.

Establish a strawberry-associated oral epithelial gene expression profile in smokers and nonsmokers following localized delivery of a novel strawberry functional confection.

Define an intraoral metabolic profile of strawberry compounds in saliva for smokers and nonsmokers.

Methods: Total RNA was isolated from tongue oral epithelium brush biopsies and gene expression was measured using RT-qPCR analyses with 44 pre-validated TaqMan gene expression assays corresponding to known tobacco-smoke associated oral transcriptome biomarkers. Anthocyanin and ellagitannins as well as other strawberry metabolites in saliva were quantified using HPLC with photodiode-array and UPLC with tandem mass spectroscopy. Salivary amylase and beta-glucosidase activity was measured colorimetrically using p-nitrophenol endpoints.

Results: A 7-gene over-expression signature (ALOX12B, CD207, HTR3A, KRT10, LOR, PNLIPRP3, TRNP1) was validated that segregated smokers and nonsmokers (adjusted p-value&lt;0.05, FDR&lt;0.20). The effects of strawberry intervention compared to placebo on this gene signature were modest and did not effectively distinguish the groups. No smoking-strawberry interaction effects achieved significance in this pilot study. In saliva, β-glucosidase activity was significantly (p=0.039) greater in smokers than nonsmokers. Anthocyanin profiles in saliva between smokers and nonsmokers differed significantly (p≤0.05). An exploratory cluster analysis was conducted to identify ellagitannin metabolizing phenotypes and examined these phenotypes in the context of gene expression profiles.

Conclusions: Significant differences between smokers and nonsmokers were observed in gene expression, salivary enzyme activity and in intraoral strawberry metabolites following administration of a strawberry functional confection. While this pilot study interrogated an existing tobacco smoke driven transcriptional profile, the global strawberry bioactive driven transcriptome remains uncharacterized. Moreover, complementary changes in oral epithelial gene expression and intraoral metabolites between smokers and nonsmokers warrant the need for long-term cancer prevention studies using strawberries.

Citation Format: Jennifer H. Ahn-Jarvis, Thomas J. Knobloch, Steve Oghumu, Ken M. Reidl, Guy Brock, Steven K. Clinton, Yael Vodovotz, Steven J. Schwartz, Christopher M. Weghorst. Validation of a tobacco smoke exposure gene expression signature and exploration of intraoral metabolite profiles following administration of a strawberry functional confection in smokers and nonsmokers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr CT105. doi:10.1158/1538-7445.AM2017-CT105