title: Nanocluster model of photothermal assay: application for high-sensitive monitoring of nicotine-induced changes in metabolism, apoptosis, and necrosis at a cellular level.
abstract: This study evaluates the capability of a photothermal (PT) assay to monitor the impact of nicotine on pancreatic cancer cells (AR42J). The specific PT response is closely proportional to nicotine concentrations at concentration range 1 nM to 100 microM, while at high concentrations of nicotine ranging from 1 mM to 50 mM, PT response shows dramatic decrease. According to the theoretical model, the mechanism of the PT assay is associated with metabolic and apoptotic-related shrinking of local cellular absorbing nanoscale zones caused by increased local absorption at low nicotine doses, while high doses of nicotine lead to apoptotic release of absorbing component (cytochrome c) into the intracellular space, and necrotic swelling of organelles, thereby causing a decrease in local absorption. This model is verified with conventional imaging and with Annexin-V Propidium iodide kits. The PT assay, in addition to its high sensitivity (3 orders of magnitude better than conventional assay), shows the potential to distinguish between various functional states of cells that are associated with changes in metabolism, early and late stages of apoptosis, and necrosis. Comparison of PT responses of pancreatic tumor cells AR42J with isolated primary pancreatic acinar cells and HepG2 cells shows a universal nature of PT assay.
authors.affiliation: University of Arkansas for Medical Sciences, Philips Classic Laser Laboratories, 4301 West Markham Street, Number 543, Little Rock, Arkansas 72205-7199, USA. zharovvladimirp@uams.edu
authors.forename: Vladimir P
authors.initials: VP
authors.lastname: Zharov
authors.forename: Valentin
authors.initials: V
authors.lastname: Galitovsky
authors.forename: Parimal
authors.initials: P
authors.lastname: Chowdhury
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D006528:Carcinoma, Hepatocellular / Q000378:metabolism / Q000473:pathology; D002460:Cell Line; D016000:Cluster Analysis; D003198:Computer Simulation; D004305:Dose-Response Relationship, Drug; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D008297:Male; D008657:Metabolic Clearance Rate / Q000187:drug effects; D008856:Microscopy, Fluorescence / Q000379:methods*; D008954:Models, Biological; D036103:Nanotechnology / Q000379:methods; D009336:Necrosis; D009363:Neoplasm Proteins / Q000378:metabolism*; D009538:Nicotine / Q000008:administration & dosage*; D010179:Pancreas / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D010190:Pancreatic Neoplasms / Q000378:metabolism* / Q000473:pathology; D010777:Photochemistry / Q000379:methods; D051381:Rats; D017207:Rats, Sprague-Dawley; D013817:Thermography / Q000379:methods*
chemical_list: D009363:Neoplasm Proteins; D009538:Nicotine