114 Evaluation of a Mucoadhesive Fenretinide Patch for Oral Cancer Chemoprevention

Thursday, March 22, 2012: 8 a.m. - 9:30 a.m.
Presentation Type: Oral Session
A.S. HOLPUCH1, M.P. PHELPS1, K. DESAI2, W. CHEN3, G.M. KOUTRAS1, M. BORDER1, B. HAN1, M. TONG1, P. PEI1, B. WARNER4, H. FIELDS5, P.E. LARSEN1, G.D. STONER6, Z. LIU3, S.P. SCHWENDEMAN2, and S.R. MALLERY1, 1Oral and Maxillofacial Surgery, Pathology, and Anesthesiology, Ohio State University, Columbus, OH, 2Pharmaceutical Sciences, University of Michigan, Ann Arbor, MI, 3College of Pharmacy, Ohio State University, Columbus, OH, 4College of Dentistry, Ohio State University, Columbus, OH, 5Orthodontics, Ohio State University, Columbus, OH, 6Medical College of Wisconsin, Milwuakee, WI
Systemic administration of vitamin A-like compounds, e.g., fenretinide, has been extensively evaluated in oral cancer chemoprevention trials.  These previous trials were largely inefficacious due to dose-limiting toxicities and sub-therapeutic chemopreventive levels. A viable alternative is local delivery which provides therapeutic levels in target tissues without deleterious systemic effects. Objectives: Determine pharmacokinetic parameters of mucoadhesive fenretinide patches placed on rabbit buccal mucosa and assess local tissue effects.  Methods: Fenretinide and blank-control patches were placed on right/left buccal mucosa, respectively, in 8 rabbits (30-minutes q.d., 10-days).  Pre-/post-application sera and post-study oral mucosal specimens were obtained for fenretinide/metabolite quantification (LC-MS/MS) and determination of chemoprevention-relevant parameters (proliferation-Ki67, differentiation-transglutaminase1 (TGase1), apoptosis-TUNEL, bioactivation-UGT1A1). Concurrent studies assessed human oral mucosal enzymatic profiles (n=8) and fenretinide’s growth modulatory effects on cultured human oral keratinocytes.  Mann-Whitney and paired t-test statistics were used. Results: Fenretinide patches delivered highest levels at the patch-mucosal interface, therapeutically-relevant levels to oral mucosa (Mean±SEM:5.59±0.44μM, n=8, p<0.001: fenretinide-treated vs. blank-treated), and undetectable sera levels. No clinical or histologic deleterious effects occurred.   Relative to rabbit-matched blank-treated mucosa, oral tissues containing 0.1-5μM fenretinide (n=6) exhibited increased intraepithelial TGase1 levels (Mean±SEM:+32.8±2.96%) and negligible effects on Ki-67 indices (Mean±SEM:-1.0±0.05%). Tissues containing >5μM (n=2) demonstrated substantially decreased TGase1 levels (Mean±SEM:-29.2±1.8%) and marked reduction of Ki-67 indices (Mean±SEM:-5.6±0.3%).  All fenretinide-treated specimens showed significant intraepithelial increases of TUNEL indices (p<0.01, greatest in tissues >5μM) and significantly increased levels of UGT1A1 expression (p<0.01, greatest in tissues <5μM).  Substantial inter-donor variations in fenretinide-metabolizing enzymes (CYP3A4, UGT1A1) were observed in human oral mucosa.  Fenretinide-treatment of keratinocytes (0-5μM) revealed optimal increases of TGase1 and involucrin at 1μM. Cell proliferation and apoptosis studies are ongoing.  Conclusion: Patch-delivered fenretinide recapitulates the favorable growth modulation previously only observed in cultured cells. This delivery strategy provides a means to clinically re-introduce an effective epithelial-relevant oral cancer chemopreventive.  [F30DE020992, R01CA129609]
This abstract is based on research that was funded entirely or partially by an outside source: NIH: F30DE020992, R01CA129609

Keywords: Biocompatibility, Cancer Chemoprevention, Delivery systems, Oral mucosa and Pharmacology
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