Article

Topical Application of a Bioadhesive Black Raspberry Gel Modulates Gene Expression and Reduces Cyclooxygenase 2 Protein in Human Premalignant Oral Lesions

Department of Oral and Maxillofacial Surgery, College of Dentistry, The Ohio State University Comprehensive Cancer Center and Solove Research Institute, Columbus, Ohio, USA.
Cancer Research (Impact Factor: 9.33). 07/2008; 68(12):4945-57. DOI: 10.1158/0008-5472.CAN-08-0568
Source: PubMed

ABSTRACT

Reduced expression of proapoptotic and terminal differentiation genes in conjunction with increased levels of the proinflammatory and angiogenesis-inducing enzymes, cyclooxygenase 2 (COX-2) and inducible nitric oxide synthase (iNOS), correlate with malignant transformation of oral intraepithelial neoplasia (IEN). Accordingly, this study investigated the effects of a 10% (w/w) freeze-dried black raspberry gel on oral IEN histopathology, gene expression profiles, intraepithelial COX-2 and iNOS proteins, and microvascular densities. Our laboratories have shown that freeze-dried black raspberries possess antioxidant properties and also induce keratinocyte apoptosis and terminal differentiation. Oral IEN tissues were hemisected to provide samples for pretreatment diagnoses and establish baseline biochemical and molecular variables. Treatment of the remaining lesional tissue (0.5 g gel applied four times daily for 6 weeks) began 1 week after the initial biopsy. RNA was isolated from snap-frozen IEN lesions for microarray analyses, followed by quantitative reverse transcription-PCR validation. Additional epithelial gene-specific quantitative reverse transcription-PCR analyses facilitated the assessment of target tissue treatment effects. Surface epithelial COX-2 and iNOS protein levels and microvascular densities were determined by image analysis quantified immunohistochemistry. Topical berry gel application uniformly suppressed genes associated with RNA processing, growth factor recycling, and inhibition of apoptosis. Although the majority of participants showed posttreatment decreases in epithelial iNOS and COX-2 proteins, only COX-2 reductions were statistically significant. These data show that berry gel application modulated oral IEN gene expression profiles, ultimately reducing epithelial COX-2 protein. In a patient subset, berry gel application also reduced vascular densities in the superficial connective tissues and induced genes associated with keratinocyte terminal differentiation.

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    • "For example, ACNrich extract from black raspberry suppressed proliferation of human oral squamous cell carcinoma cells (Rodrigo et al., 2006) and reduced the number of chemically-induced tumours in the hamster cheek pouch (Casto et al., 2002) and the oesophagus and colon in laboratory rodents (Wang & Stoner, 2008). Also, topical application of ACN-rich berry gel reduced heterozygosity indices (Shumway et al., 2008) and COX-2 (Mallery et al., 2008) in premalignant oral lesions in human subjects. Such observations have provided impetus to the development of delivery vehicles for ACN, such as muco-adhesive gel (Mallery et al., 2007), to increase exposure of oral tissues to ACN. "
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