Metabolomic Profiling of MYC-regulated Lymphoma

Serum samples (100 μl) were assessed by ultra performance liquid chromatography (UPLC) and quadruple/time-of-flight mass spectrometry. The mass spectrometer was operated in both positive and negative electrospray ionization (ESI+/ESI−) mode. The UPLC-quadruple/time-of-flight mass spectrometry ESI+ and ESI− raw data were analyzed by the MarkerLynx Applications Manager version 4.1 (Waters Corp., Milford, MA, USA) and total ion chromatography was generated. To identify different metabolomic profile between MYC-high and MYC-low groups, multivariate analysis was performed using SIMCA-P software version 12.0 (Umetrics AB, Umeå, Sweden). The unsupervised principal component analysis and supervised orthogonal partial least squares-discriminant analysis (OPLS-DA) models were constructed. Reliability of OPLS-DA models was validated by response permutation test. Quality controls were prepared by mixing the same volume of each sample and repeatedly injected during the assay to monitor instrumental stability and avoid systematic bias. As for cell metabolites, lymphoma cells (1 × 10⁷/ml) were extracted by freeze-thaw method and cell lysate (100 μl) was used for UPLC-triple quadrupole mass spectrometry analysis. The detailed parameters were as previously reported.^{14 (link)}