Abstract LB-259: The potent and selective Axl/Mer dual inhibitor ONO-9330547, shows promising single agent activity in non-small cell lung cancer (NSCLC)
Authors: Tanaka Kohei , Yoshizawa Toshio , Yasuhiro Tomoko , Fujikawa Ryu , Koike Tomoya , Kawabata Kazuhito 
Published: August 2015

Purpose: Axl and Mer are members of the TAM (Tyro3, Axl, Mer) receptor tyrosine kinase family and they play an important role in regulating cell proliferation, survival, migration and cytokine production. Axl/Mer are known to be over-expressed in various types of haematological and solid tumour cancers and have been reported as poor prognostic factors. ONO-9330547 is a novel, small molecule Axl/Mer dual inhibitor, which potently inhibits phosphorylation of both Axl (P-Axl) and Mer (P-Mer), with higher selectivity against other TKs in a cell-based assay. We have previously reported that 3 mg/kg twice daily dosing of ONO-9330547 for 24 days in an AML xenograft model, induced complete remission (Yasuhiro ASH 2014). Axl also appears to play a key role in epithelial-to-mesenchymal transitions (EMTs), which is involved in metastases and drug resistance in solid tumour such as NSCLC and breast cancer. Here, we investigated anti-tumour activity of ONO-9330547 in NSCLC cell lines.

Methods: Phosphorylated proteins were detected by Western blotting. In a two-dimensional (2D) assay, cells were treated with ONO-9330547 at concentrations up to 1μmol/L for 72 hours. Cell viability was determined by WST-8 Assay. In a clonogenic assay, cells in agarose solution were plated and the medium containing a ONO-9330547 were overlaid. After 17-21 days incubation, colonies were fixed, stained and counted. Luciferase-expressing NSCLC cell lines were injected intravenously into female SCID mice to mimic a model of disease metastases. After implantation, ONO-9330547 was administered orally at 1 or 10 mg/kg once daily (QD) for 41 days. For detecting tumour cells, D-luciferin solution was administered and total photon counts were measured once a week by IVIS imaging system.

Results: ONO-9330547 strongly inhibited both P-Axl and the downstream signaling P-Akt upon Axl stimulation in NSCLC cells with an IC50 of 0.49 and 1.5 nmol/L respectively, while inhibiting cell growth partially in 2D assay. Interestingly, in a clonogenic assay, which is a common method to monitor anchorage-independent growth of cells, ONO-9330547 strongly inhibited colony growth of three NSCLC cell lines, NCI-H1299, A549, NCI-H229 (EGFR inhibitor-resistant cells) with IC50 of 4.4, 19 and 58 nmol/L, respectively. In a NSCLC model of metastases, the treatment of ONO-9330547 at dose of 1 and 10 mg/kg QD for 41 days resulted in significant inhibition (75 and 84%) of metastases in lungs compared with vehicle treated mice.

Conclusion: ONO-9330547 is a highly potent dual Axl/Mer inhibitor with evidence of efficacy in NSCLC cells. Additional work to investigate the activity of ONO-9330547 alone and in combination with other therapeutic agents in other types of solid tumours are currently underway.

Citation Format: Kohei Tanaka, Toshio Yoshizawa, Tomoko Yasuhiro, Ryu Fujikawa, Tomoya Koike, Kazuhito Kawabata. The potent and selective Axl/Mer dual inhibitor ONO-9330547, shows promising single agent activity in non-small cell lung cancer (NSCLC). [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr LB-259. doi:10.1158/1538-7445.AM2015-LB-259