Direct visualization and quantification of the anticancer agent, cis‐diamminedichloro‐platinum(II), in human lung cancer cells using in‐air microparticle‐induced X‐ray emission analysis

Abstract

The authors designed an elemental analysis system using an ion microbeam combined with a microparticle-induced X-ray emission (micro-PIXE) method for the analysis of biomedical samples in air with a spatial resolution of 1 μ μ μ μm (in-air micro-PIXE system). This system was used to develop an imaging and quantification method for intracellular cis-diamminedichloro-platinum(II) (CDDP) in a human lung cancer cell line. A human lung adenocarcinoma cell line, A549, was cultured and nuclear labeling was carried out by incubating the cells with BrdU. The cells were then exposed to CDDP at concentrations ranging from 1 μ μ μ μmol to 1 mmol, for 30 min to 24 h. After drug treatment, samples were washed and frozen with liquid nitrogen, and freeze-dried for 24 h. Standard samples were made using agar containing several concentrations of CDDP. Experiments using standard samples showed a linear correlation between CDDP concentration and platinum signal strength. No clear platinum signal was detected after exposure to CDDP for 24 h at doses between 1 and 100 μ μ μ μmol. However, significant platinum signals were observed at 1 mmol. When nucleus and cytoplasm visualization was sufficiently clear to efficiently use in-air micro-PIXE, the platinum image quality was considered satisfactory. The detected signals of CDDP were stronger in the nucleus than in the cytoplasm. A timecourse study showed increased CDDP uptake in cells after longer drug exposure periods. The present study demonstrates the application of element analysis using in-air micro-PIXE to biomedical samples. The use of this system enables the high-resolution visualization of intracellular CDDP distribution and measurement of intracellular CDDP concentrations. (Cancer Sci 2008; 99: 901-904)

Bio-metals imaging and speciation in cells using proton and synchrotron radiation X-ray microspectroscopy

“…Proton microprobe analysis showed that platinum effectively reached the nucleus Review. Bio-metals imaging and speciation R. Ortega et al S651 of the cells exposed to cisplatin but with a low specificity (Moretto et al 1995;Ortega et al 1996;Mauthe et al 1998;Sakurai et al 2008). Trace element quantification in cisplatin-resistant cells also revealed a strong increase in the copper content (Ortega et al 1996), which can be linked to the expression of copper transport proteins in cisplatin-resistant cells (Ishida et al 2002).…”

Bioanalytics in Quantitive (Bio)imaging/Mapping of Metallic Elements in Biological Samples

“…An example is the application of this method in (bio)imaging intracellular cis-diamminedichloridoplatinum (CDDP) in a human lung cancer cell line (Sakurai et al, 2008). The results of this research show that accumulation of cis-platin in human lung cancer cells increased with drug exposure time.…”

“…The results of this research show that accumulation of cis-platin in human lung cancer cells increased with drug exposure time. Because the concentration of this complex is very high and most cells lose viability after 24 h exposure to CDDP, the uptake of CDDP in the cells must occur by a passive mechanism under no physiological condition (Sakurai et al, 2008). (Bio)imaging studies on toxic heavy metals can be very important from a toxicology point of view.…”

“…Na, K, TiBecker et al, 2010;Chandra et al, 2013;Kim et al 2008a Distribution of metals in cells Na, K, Ca, Pt, ThChandra, 2010; Fourre et al, 1992;Guerquin-Kern et al, 2005;Mai et al, 2006;Nygren et al, 2007;Petibois, 2013 Pt, V, Fe, Cu, Zn, Mn Kro sniak et al, 2013Sakurai et al, 2008; Tanaka et al, 2010 …”

Evaluation of the Uptake of CDDP-Containing Polymeric Micelles in Single Pancreatic Cancer Cells

“…X-ray fluorescence spectrometry has been used for obtain the spatial elemental map for the biological samples. 7,8 In this study, we used the particle induced X-ray emission analysis technique with micron-sized probe beams (µ-PIXE analysis) for quantification of platinum in single cells. The aim of this study was to evaluate the kinetics of the cisplatin micelle by measuring the uptake and the intra-cellular distribution of platinum by using µ-PIXE analysis.…”