Drug resistance is the main cause of cancer recurrence and a major obstacle to the success of anticancer therapy. NRF2, a pivotal transcription factor regulates antioxidant response and detoxification, has been shown to participate in the development of cancer drug resistance. Functional suppression of NRF2 rendered cancer cell more susceptible to anticancer treatments. Beilschmiedia tsangii Merr. (Lauraceae) is a medium-sized evergreen tree. It has been reported that Beilschmiedia extract showed a strong antioxidant activity. In continuation of our bioactivity studies on this species, we tested the effects of 23 compounds isolated from the B. tsangii on NRF2 activity. We identified rel-(7R,8R,7′R,8′R)-3,4,3′,4′-dimethylene-dioxy-5,5′-dimethoxy-7,7′-epoxylignan (BT04) significantly inhibited NRF2 activity in liver cancer cell (Huh7) with an IC50 value of 17 μM, but not in keratinocyte (HacaT cell). By contrast, luteolin, a known NRF2 inhibitor, suppressed NRF2 activity in both Huh7 cell and HacaT cell. Moreover, the mRNA level of NRF2 target genes, NQO1 and HO1, were significantly decreased in Huh7 upon BT04 treatment, while those NRF2 target genes remained unchanged in BT04-treated HacaT cell. A moderate cytotoxic effect of BT04 on Huh7 cell was also observed. Accordingly, our result suggested that BT04 can specifically inhibit NRF2 activity in liver cancer, which in turn indicated that BT04 could be a potential adjuvant to improve chemoresistance.

Citation Format: Yi Siao Chen, Chih Chung Lai, Yi Ping Kuo, Hsun Shuo Chang, Ih Sheng Chen, Chia-Hung Yen. Identification of compound isolated from Beilschmiedia tsangii as a liver cancer specific NRF2 inhibitor [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 190. doi:10.1158/1538-7445.AM2017-190