Abstract A38: In vitro and in vivo characterization of a novel NEK2 inhibitor MBM5 for the treatment of gastrointestinal cancer

Abstract

NEK2 is a conserved mitotic regulator critical for centrosome splitting and correct chromosome segregation. Aberrant expression of NEK2 has been found in a variety of human cancers, making it an attractive molecular target for the design of novel anticancer therapeutics. Here we report the discovery of a novel small molecule NEK2 inhibitor, MBM5, for the treatment of gastrointestinal cancer cells. A series of compounds have been synthesized to determine their potency against NEK2. Through in vitro kinase assay, we found that compound MBM5 exhibited a significant inhibitory effect on the kinase activity of NEK2. MBM5 also demonstrated strong inhibition on proliferation of a broad spectrum of tumor cells, especially gastrointestinal cancer cells (IC50<1 μM). Treating cells with MBM5 triggered a significant accumulation of cells at G2/M phase and a modest accumulation of cells with >4N DNA content. By releasing cells from the G1/S boundary, we found that the progression from G2/M to G1 phases were completely abrogated in the presence of MBM5. In consistence, we further observed that MBM5 induced chromosomal misalignment in metaphase and slightly increased the level of multinucleated cells, confirming the perturbed mitotic progression. And these was correlated with MBM5-inhibited phosphorylation of Hec1 and Histone 3. Over time, the accumulation of chromosomal abnormalities led to apoptosis, as evidenced by the increased population of Annexin-V/PI positive cells, the up-regulated expression of cleaved-caspase 3 and the cleavage of PARP. In vivo daily treatment with MBM5 (ip, 20 mg/kg, 3 weeks) significantly inhibited the growth of MGC-803 gastric tumor and HCT-116 colonal tumor xenografts. Altogether, this study demonstrates that MBM5 interfered with NEK2 functions both in cells and tumor xenografts, thus showing its potential in anti-cancer treatment regimens. Citation Format: Yanfen Fang, Xiongwen Zhang, Wenhao Hu, Yannan Kong, Hong Wang, Mengli Zhu. In vitro and in vivo characterization of a novel NEK2 inhibitor MBM5 for the treatment of gastrointestinal cancer. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2015 Nov 5-9; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2015;14(12 Suppl 2):Abstract nr A38.