Targeting NF-kB inducing kinase (NIK) for developing anti-cancer drugs.

A. Al-Obaidi1, A. McCluskey1, A. Sorensen1, K. Ho1, D. Breen1, G. Berretta1, A. Alsfouk1, C. West1, N. Anthony1, J. Edwards2, C. Suckling1, M. Boyd1, S. MacKay1, A. Paul1, R. Plevin1. 1Strathclyde Institute of Pharmacy and Biomedical Sciences, Strathclyde University, Glasgow, UNITED KINGDOM, 2Institute of Cancer Sciences, Glasgow University, Glasgow, UNITED KINGDOM.

Introduction: Pancreatic cancer has a very poor prognosis, it is the 4th ranked cancer worldwide in terms of mortality (Siegel et al., 2015). The Nuclear factor kappa B (NFκB) cascade is comprised of two interdependent pathways, recognized as the classical or canonical pathway and the non-canonical pathway. Studies have linked hyper-activation of both pathways to pancreatic tumorigenesis (Sohn et al., 2000). NFκB-inducing kinase (NIK) is a kinase which plays a key role in regulating the non-canonical NFκB pathway. The aims of this study are firstly, to characterise both NFκB pathways in a pancreatic cancer cell line and secondly, to assess the effect a novel, recently described NIK inhibitor (CW15420) as a potential anti-cancer drug.

Method: All the experiments were conducted in the pancreatic cancer cell line, Panc-1. Western blotting was used to determine the activation of NFκB pathways. The phosphorylation p100 and processing of p100 to p52 were used to measure the activity of non-canonical part of the pathway, while IκBα degradation and phosphorylation of p65 measured the canonical pathway. FACS analysis was used to assess cell cycle distribution and a clonogenic assay to determine proliferation and cells survival.

Results: In Panc-1 cells, Lymphotoxin (LTα1β2) stimulated the non-canonical NFκB pathway, inducing phosphorylation of p100 after 4h of stimulation (fold increase 27.75± 2.11, p<0.01 n=3), while formation of p52 increased 33.96 ± 1.79 fold (p< 0.001, n=3) compared with control. TNFα stimulated the canonical NFκB pathway as evidenced by degradation of IκÎ’α and phosphorylation of p65. Pre-treated of cells with the NIK inhibitor (CW15420) (0.1-10μM) for 1h prior to exposure to lymphotoxin inhibited the phosphorylation of p100, with an IC50 value of 0.19 ± 0.01μM (n=3). The formation of p52 was also inhibited, an IC50 value of 1.62 ± 0.44 μM (n=3) was recorded. In contrast, CW15407 had no effect upon TNFα-stimulated ΙκÎ’α degradation and phosphorylation of p65. Panc-1 cells exposed to CW15407 (3μM) for 48h, showed a significant arrest within G2/M of the cell cycle compared with control (% cells in G2/M, CW15420 = 28.8 ± 4.8, control = 13.2 ± 1.4, n=3). Cell proliferation was also substantially inhibited.

Conclusion Our study demonstrated that CW15407 inhibited non-canonical NFκB signalling and cell proliferation. Targeting NIK may be a good strategy for anti-cancer drug development. References: SIEGEL, R. et al, 2015. CA Cancer J Clin, 65, 5-29. SOHN, T. et al. 2000. J Gastrointest Surg, 4, 567-79. ADDIN EN.REFLIST