Abstract 1289: Conjugation of indomethacin with novel oleanolic acid oximes increases its Nrf2 and NF-κB signaling pathways modulating effect in pancreatic cancer cells

Chronic inflammation is a key factor in the etiology of neoplastic diseases, including pancreatic cancer. Nonsteroidal anti-inflammatory drugs (NSAIDs) were approved for the chemoprevention of colon tumors and suggested for pancreas cancers prophylaxis. Anti-inflammatory and anti-tumorigenic activities are also exerted by naturally occurring and synthetic triterpenoids. Coupling of triterpenoid analogues with NSAIDs may enhance this effect and prevent the unfavorable side effects related to NSAIDs long-term use. In this study novel oleanolic acid oxime (OAO) derivatives conjugated with indomethacin (IND) differing in substitution group at position C-17 were evaluated in the context of their possible modulating effect of Nrf2-ARE and NF-κB signaling pathways in pancreatic cancer cells.PSN-1 cells were incubated for 24h with IND and OAO-IND derivatives at the concentrations of 10µM and 20µM selected based on the results of the MTT assay. The activation of Nrf2 and NF-κB was assessed by the evaluation of its translocation into the nucleus and binding to specific DNA sequences by the ELISA assay. Expression of Nrf2, SOD-1, NF-κBp50, NF-κBp65 and COX-2 was evaluated by RT-PCR and Western blot methods.Cell viability was affected mostly by 3-indomethacinoxyiminoolean-12-en-28-oic acid morpholide and 3-indomethacinoxyiminoolean-en-28-oic acid benzyl ester. The level of Nrf2 in the nucleus and binding to ARE sequence was decreased in PSN-1 cells, similarly as was NF-κBp50 and NF-κBp65 binding and nuclear accumulation. As result of diminished activation of these transcription factors decreased expression of SOD-1 and COX-2 i.e. mRNA and protein levels were found. These results indicate that the OAO-IND derivatives, particularly morpholide and benzyl ester conjugates, are more potent suppressors of NF-κB signaling pathway than IND alone. Moreover, conjugation of IND with novel OAO may protect cancer cells against chemoresistance through inhibition of the Nrf2-ARE pathway. Those novel compounds might be considered the potential modulators of hepatocellular carcinoma therapy and chemopreventive agents. Funding: This work was supported by Polish National Science Centre, grant 2016/21/B/NZ7/01758. Citation Format: Wanda Baer-Dubowska, Maria Narozna, Violetta Krajka-Kuźniak, Barbara Bednarczyk-Cwynar. Conjugation of indomethacin with novel oleanolic acid oximes increases its Nrf2 and NF-κB signaling pathways modulating effect in pancreatic cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1289.