Lyophilized strawberries prevent 7,12-dimethylbenz[α]anthracene (DMBA)-induced oral squamous cell carcinogenesis in hamsters

This study evaluated the ability of lyophilized strawberries to prevent 7,12-dimethylbenzloc]anthracene (DMBA)-induced tumor development in hamster cheek pouch. The experimental diet containing 5% strawberries was given to hamsters during or after DMBA treatment, or throughout the entire bioassay. Our data indicate that tumor incidence, multiplicity, volume and histologic grade of oral precancerous lesions were reduced in animals fed the experimental diet compared to those fed the control diet. We chemically identified and quantified the main phytochemicals by high performance liquid chromatography/tandem mass spectrometry. Fourteen quantified compounds were classified to three categories: anthocyanins (48.8%, w/w of the phenolics), ellagitannin/ellagic acid/ellagic acid derivates (42.9%) and flavonols (8.3%). We further elucidated the molecular mechanisms underlying preventive activities of strawberries. Our mechanistic studies show that strawberries suppress cell proliferation, angiogenesis and oncogenic signaling. Moreover, feeding 5% strawberries also significantly decreased arachidonic acid metabolism and formation of 8-hydroxydeoxyguanosine. These observations suggest that strawberries inhibit DMBA-induced oral cancer in hamsters through suppression of multiple oncogenic events, and thus may serve as alterative agents for oral cancer prevention in humans. (C) 2015 Elsevier Ltd. All rights reserved.