LAUSR

The Notch signaling pathway is an evolutionarily conserved cell signaling pathway. It plays a central role in cell fate decisions and differentiation. The bioavailability of sclareol has been widely studied due to its anti-carcinogenic and antioxidant effects. However, chemo preventive effects of sclareol on notch signaling in 7, 12-dimethylbenz [a] anthracene (DMBA) induced hamster buccal pouch(HBP) carcinogenesis remain to be fully elucidated. In the present study, tumors were induced by applying 0.5% DMBA topically to HBP thrice a week for 14 weeks and sclareol was orally administered at a dose of 20mg/kg body weight on alternate days of DMBA painting. We analyzed expression of Notch signaling in DMBA induced oral squamous cell carcinoma (OSCC) in experimental oral carcinogenesis and inhibition of notch signaling by sclareol. This study thus observed up regulation of Notch1, Notch2, Jagged1, Hes1 and Hey1 in DMBA alone induced hamsters. Furthermore, oral administration of sclareol led to reduced Notch1, Notch2 activation and expression of Jagged-1 and its downstream targets of Hes-1 and Hey-1 in tumor bearing hamsters. In addition, sclareol treatment increased pro-apoptotic and decreased anti-apoptotic proteins survival indicating apoptosis through activation of caspase 3, and promoting cell death by dysregulation of cyclin D1 levels in tumor bearing hamsters. Immunohistochemical examination showed that Notch intracellular domain accumulates in the nucleus of cells in DMBA induced hamster buccal pouch carcinogenesis, and Jagged1 was found to be dysregulated in sclareol treated tumor animals. In conclusion, the results provide an important new insight of Notch signaling pathway for a potential therapeutic target for oral cancer. Citation Format: Aiyavu Chinnaiyan, Anandhi Nallu, Suresh Kathiresan. Sclareol induces apoptosis and inhibits notch signaling in hamster oral carcinogenesis [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 10.