Abstract 106: Diclofenac hybrids with oleanolic acid oximes modulate key signaling pathways in pancreatic cancer cells
Authors: Narozna Maria , Krajka-Kuzniak Violetta , Kleszcz Robert , Baer-Dubowska Wanda 
Published: June 2022

Pancreatic cancer is characterized by constitutive activation of mitogen-activated protein kinases (MAPKs) like JNK and p38 determining its malignant phenotypes. Overexpression of NF-κB and COX-2 involved in inflammation contributes to increased cell growth and invasiveness. The latter might be related to the activated AKT pathway.

Nonsteroidal anti-inflammatory drugs were suggested for pancreas cancers prophylaxis. Naturally occurring oleanolic acid (OA) was shown to possess anti-inflammatory and anti-tumorigenic activities. Coupling its analogs with NSAIDs may enhance this effect. Our study aimed to evaluate the effect of two oleanolic acid oximes derivatives conjugated with diclofenac (DCL), 4c (3-diclofenacoxyiminoolean-12-en-28-oic acid benzyl ester) and 4d (3-diclofenacoxyiminoolean-12-en-28-oic acid morpholide) on inflammation-related pathways, MAPK and NF-κB, cell cycle arrest and ROS formation in PSN-1 pancreatic cancer cells. PSN-1 cells were incubated with DCL, 4c or 4d at the concentration of 30µM. Activation of NF-κB was assessed by measuring binding of its p50 and p65 subunits to DNA using ELISA method. Their nuclear concentrations were determined by Western blot. RT-PCR was used to evaluate NF-κB subunits and COX-2 mRNA levels. Bead-based immunoassay determined the cytosolic levels of p38, JNK, CREB, AKT, P70S6K and STAT3 proteins. Cell cycle distribution and ROS formation were assessed using flow cytometry. Conjugate 4d significantly reduced nuclear level of p65 subunit and its mRNA expression, although compound 4c had more significant impact on COX-2 expression. Both derivatives significantly diminished p65 DNA binding, but only 4d had significant effect on p50. Both compounds reduced ROS production, but neither of them affected the cell cycle arrest. We observed decreased cytosolic AKT level along with increased levels of unphosphorylated JNK and p38 kinases which may have an antagonistic effect on proliferation by reducing activity of inflammatory mediators acting as tumor promoters. AKT decrease after treatment with 4d derivative might be the cause of increased unphosphorylated CREB level. Accumulation of p38 and JNK in cytosol could be a result of decreased ROS production and/or cause increased CREB protein level. Additionally, increased STAT3 cytosolic level suggests inhibition of mTORC1 pathway that explains reduced p70S6 kinase. Overall, these results suggest that OAO-DCL morpholide conjugate may affect both NF-κB and MAPK signaling pathways in pancreatic cancer cells. Further studies are required to explain detailed mechanism of these modifications.

Funding: Studies were supported by Polish National Science Centre grant 2016/21/B/NZ7/01758.

Acknowledgments: Authors thank Dr. Gary Gorbsky, Chair of Cell Cycle & Cancer Biology Program in Oklahoma Medical Research Foundation for supporting financing Maria Narozna conference participation.

Citation Format: Maria Narozna, Violetta Krajka-Kuzniak, Robert Kleszcz, Wanda Baer-Dubowska. Diclofenac hybrids with oleanolic acid oximes modulate key signaling pathways in pancreatic cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 106.