title: Qualitative and quantitative analysis of tumor cell metabolism via stable isotope labeling assisted microfluidic chip electrospray ionization mass spectrometry.
abstract: In this work, a stable isotope labeling assisted microfluidic chip electrospray ionization mass spectrometry (SIL-chip-ESI-MS) platform for qualitative and quantitative analysis of cell metabolism was developed. Microfluidic cell culture, drug-induced cell apoptosis analysis, and cell metabolism measurements were performed simultaneously on the specifically designed device. MCF-7 cells were cultivated in vitro and exposed in anticancer agent (genistein and genistein-d(2)) for cell-based drug assay. A dual-isotopic labeling was presented for effective qualitative analysis of multiplex metabolites. Interestingly, three coeluting pairs of isotopomers appeared with an m/z difference of two. Despite complex biological matrixes, they can be easily recognized and identified by chip-ESI-MS/MS, which significantly facilitates candidate biomarker discovery. The quantitative performance of this system was evaluated using genistein as a model drug by means of stable isotope dilution analysis. The linear equation obtained is y = 0.06x - 3.38 × 10(-3) (R(2) = 0.995) at the dynamic range from 0.5 to 40 μM. The detection limit is 0.2 μM. The method shows an excellent stability of 2.2% relative standard deviation (RSD) and a good repeatability of 5.5% RSD. Our results have successfully demonstrated the capability of selective and quantitative analysis of cell-based drug absorption and metabolites with high stability, sensitivity, and repeatability on the chip-ESI-MS system. Consequently, the present device shows promise as a high-throughput, low-cost, and online platform for cell metabolism studies and drug screening processes.
authors.affiliation: Beijing Key Laboratory of Analytical Methods and Instrumentation, Department of Chemistry, Tsinghua University, Beijing 100084, People's Republic of China.
authors.forename: Qiushui
authors.initials: Q
authors.lastname: Chen
authors.forename: Jing
authors.initials: J
authors.lastname: Wu
authors.forename: Yandong
authors.initials: Y
authors.lastname: Zhang
authors.forename: Jin-Ming
authors.initials: JM
authors.lastname: Lin
mesh_terms: D000970:Antineoplastic Agents / Q000032:analysis* / Q000378:metabolism / Q000494:pharmacology; D045744:Cell Line, Tumor; D019833:Genistein / Q000032:analysis / Q000378:metabolism / Q000494:pharmacology; D006801:Humans; D007553:Isotope Labeling; D008660:Metabolism / Q000187:drug effects; D046210:Microfluidic Analytical Techniques; D009369:Neoplasms / Q000378:metabolism; D021241:Spectrometry, Mass, Electrospray Ionization
chemical_list: D000970:Antineoplastic Agents; D019833:Genistein