Cellular Uptake of Platinum Nanoparticles in Human Colon Carcinoma Cells and Their Impact on Cellular Redox Systems and DNA Integrity

Abstract

Supercritical fluid reactive deposition was used for the deposition of highly dispersed platinum nanoparticles with controllable metal content and particle size distribution on beta-cyclodextrin. The average particle size and size distribution were steered by the precursor reduction conditions, resulting in particle preparations <20, <100, and >100 nm as characterized by transmission electron microscopy and scanning electron microscopy (SEM). These particle preparations of different size distributions were used to address the question as to whether metallic platinum particles are able to invade cells of the gastrointestinal tract as exemplified for the human colon carcinoma cell line HT29 and thus affect the cellular redox status and DNA integrity. Combined focused ion beam and SEM demonstrated that platinum nanoparticles were taken up into HT29 cells in their particulate form. The chemical composition of the particles within the cells was confirmed by energy-dispersive X-ray spectroscopy. The potential influence of platinum nanoparticles on cellular redoxsystems was determined in the DCF assay, on the translocation of Nrf-2 and by monitoring the intracellular glutathione (GSH) levels. The impact on DNA integrity was investigated by single cell gel electrophoresis (comet assay) including the formation of sites sensitive to formamidopyrimidine-DNA-glycosylase. Platinum nanoparticles were found to decrease the cellular GSH level and to impair DNA integrity with a maximal effect at 1 ng/cm(2). These effects were correlated with the particle size in an inverse manner and were enhanced with increasing incubation time but appeared not to be based on the formation of reactive oxygen species.

Effects triggered by platinum nanoparticles on primary keratinocytes

“…However, such DNA damage was not accompanied by the formation of ROS. 23,24 In this study, we used PtNPs coated with PVP, which represent a polymer increasingly widespread in medicine and foodstuffs. First of all, PVP is used as a binder in many pharmaceutical tablets.…”

Ganoderma atrum polysaccharide attenuates oxidative stress induced by d-galactose in mouse brain

“…Enzymatic free radical scavenging systems, such as SOD, CAT and GPx, are major antioxidant enzymes, all of which physiologically reduce ROS levels (Poon et al, 2004;Peng et al, 2009;Sies and Murphy, 1991). GSH is the major cellular defense system against oxidants which reacts non-enzymatically with hydroxyl radicals to produce GSSG (Griffith, 1999;Odat et al, 2007;Pelka et al, 2009). It is normally maintained in a reduced state via NADPHdependent enzymes, specifically GSH-Rd (Lu et al, 2007).…”

Suppressive effects of electrochemically reduced water on matrix metalloproteinase-2 activities and in vitro invasion of human fibrosarcoma HT1080 cells

“…A localization study using bright-field scanning transmission electron microscopy has visualized intracellular Pt nanoparticles (Gehrke et al 2011). Moreover, scanning electron microscopy in combination with the focused ion beam milling method revealed that Pt nanoparticles are taken up by cells (Pelka et al 2009). Our data and others indicate that Pt nanoparticles are taken up by cells.…”

“…There are studies addressing cellular uptake mechanisms for nanoparticles, and several mechanisms have been proposed to explain the uptake of gold and Pt nanoparticles. These nanoparticles are taken into cells by phagocytosis (Pelka et al 2009;Krpetic et al 2010), endocytosis including receptor-mediated endocytosis (Chithrani 2010;Shan et al 2011;Zhang et al 2011;Ma et al 2011), pinocytosis (Shukla et al 2005) or simple diffusion (Taylor et al 2010). The term endocytosis includes phagocytosis and pinocytosis depending on the size of materials taken up by cells.…”