Abstract 350: Visualizing alectinib distribution in mice brain by using MALDI mass spectrometry imaging technique

Abstract

Abstract [Introduction] In the development of anticancer drug, measurement of drug concentration in target tissue has been thought to be crucial for predicting its efficacy and safety. However, measuring homogenized tissue by using quantitative liquid chromatography tandem mass spectrometry (LC-MS/MS) completely loss the spatial information of the compound in a target tissue. Mass spectrometry imaging (MSI) has been recently applied as innovative tools to detect pharmaceutical distributions in heterogeneous targets; however, it still needs to be improved in quantitative capability or reproducibility. [Purpose] We propose quantitative approach for MSI (qMSI) that administere matrix-assisted laser desorption ionization (MALDI)-MSI, concurrently with LC-MS/MS by using serial sections. We applied qMSI for visualizing spatial distribution of alectinib, novel ALK inhibitor, in mouse brain and examined the effect of MDR1 (p-glycoprotein) on the pharmacokinetic profiles in FVB and Mdr1a/b knockout mice. [Method] Pharmacokinetic study of alectinib was conducted in FVB and Mdr1a/b KO mice. Plasma, cerebrospinal fluid (CSF) and brain tissue were collected at 1, 1.5, 2, and 4 hours after a single oral administration dose of 4 and 20 mg/kg. The concentration of alectinib in plasma, CSF and brain tissue sections was measured by LC-MS/MS. The distribution of alectinib in mice brain tissue section was visualized by qMSI that we established. [Results] Developing qMSI showed the brain distribution of alectinib in the range from 1.2 to 952.6 pg/mm2 per each section, and the results made with qMSI were in excellent agreement with the complementary measurements by using laser-micro dissection to verify the exposure level. While plasma alectinib concentrations had no difference between both mice, the diffuse alectinib distributions in brain were observed in Mdr1a/b knockout compared with that in FVB mice. The dominant localization of alectinib in choroid plexus and brain blood vessels of FVB mice was observed by 20 μm resolution MSI analysis. [Conclusion] Our qMSI technique is expected to contribute to the development of anticancer drugs and translational research by visualizing drug distribution in target organs and tumors. Citation Format: Hiroaki Aikawa, Mitsuhiro Hayashi, Shoraku Ryu, Makiko Yamashita, Naoto Ohtsuka, Masanobu Nishidate, Akinobu Hamada. Visualizing alectinib distribution in mice brain by using MALDI mass spectrometry imaging technique. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 350.