Quantitative Evaluation of Cisplatin Uptake in Sensitive and Resistant Individual Cells by Single-Cell ICP-MS (SC-ICP-MS).

One of the main limitations to the Pt-therapy in cancer is the development of associated drug resistance that can be associated with a significant reduction of the intracellular platinum concentration. Thus, intracellular Pt concentration could be considered as a biomarker of cisplatin resistance. In this work, an alternative method to address intracellular Pt concentration in individual cells is explored to permit the evaluation of different cell models and alternative therapies in a relatively fast way. For this aim, total Pt analysis in single cells has been implemented using a total consumption nebulizer coupled to inductively coupled plasma mass spectrometric detection (ICP-MS). The efficiency of the proposed device has been evaluated in combination with flow cytometry and turned out to be around 25% (cells entering the ICP-MS from the cells in suspension). Quantitative uptake studies of a nontoxic Tb-containing compound by individual cells were conducted and the results compared to those obtained by bulk analysis of the same cells. Both sets of data were statistically comparable. Thus, final application of the developed methodology to the comparative uptake of Pt-species in cisplatin resistant and sensitive cell lines (A2780cis and A2780) was conducted. The results obtained revealed the potential of this analytical strategy to differentiate between different cell lines of different sensitivity to the drug which might be of high medical interest.