In reply to Dr. Olive

Mahrhofer, Hartmut; Bürger, Susan; Oppitz, Ulrich; Flentje, Michael; Djuzenova, Cholpon S.

doi:10.1016/j.ijrobp.2006.02.015

Cited by 1 publication

(2 citation statements)

References 4 publications

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“…These two phosphorylations are representative protein level indicators of IR response. As seen in Figure , dose-dependent increases in phosphorylation were observed consistent with published results for both p53(Ser15) and γH2AX(Ser139) 1 Western blots showing a dose-dependent increase in phosphorylation of γH2AX(Ser139) and p53(Ser15) after γ-irradiation of TK6 cells.…”

Section: Resultssupporting

confidence: 89%

“…As seen in Figure 1, dosedependent increases in phosphorylation were observed consistent with published results for both p53(Ser15) 29 and γH2AX(Ser139). 30 Multivariate Data Analysis of Irradiated Cells Demonstrates Dose-Dependent Effects on the Metabolome. Cell extracts containing hydrophilic metabolites from the irradiated TK6 cells were analyzed by UPLC-ESI-TOFMS operating in positive ionization mode.…”

Section: Resultsmentioning

confidence: 99%

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UPLC-ESI-TOFMS-Based Metabolomics and Gene Expression Dynamics Inspector Self-Organizing Metabolomic Maps as Tools for Understanding the Cellular Response to Ionizing Radiation

et al. 2008

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Global transcriptomic and proteomic profiling platforms have yielded important insights into the complex response to ionizing radiation (IR). Nonetheless, little is known about the ways in which small cellular metabolite concentrations change in response to IR. Here, a metabolomics approach using ultraperformance liquid chromatography coupled with electrospray time-of-flight mass spectrometry was used to profile, over time, the hydrophilic metabolome of TK6 cells exposed to IR doses ranging from 0.5 to 8.0 Gy. Multivariate data analysis of the positive ions revealed doseand time-dependent clustering of the irradiated cells and identified certain constituents of the water-soluble metabolome as being significantly depleted as early as 1 h after IR. Tandem mass spectrometry was used to confirm metabolite identity. Many of the depleted metabolites are associated with oxidative stress and DNA repair pathways. Included are reduced glutathione, adenosine monophosphate, nicotinamide adenine dinucleotide, and spermine. Similar measurements were performed with a transformed fibroblast cell line, BJ, and it was found that a subset of the identified TK6 metabolites were effective in IR dose discrimination. The GEDI (Gene Expression Dynamics Inspector) algorithm, which is based on self-organizing maps, was used to visualize dynamic global changes in the TK6 metabolome that resulted from IR. It revealed dose-dependent clustering of ions sharing the same trends in concentration change across radiation doses. "Radiation metabolomics," the application of metabolomic analysis to the field of radiobiology, promises to increase our understanding of cellular responses to stressors such as radiation.High-throughput studies of the molecular and cellular effects of ionizing radiation (IR) have depended on "omic"1 profiling technologies, particularly genomic, transcriptomic, and proteomic platforms.2-6 Such efforts have discovered IR-induced perturbations of DNA, RNA, and protein molecules and have been successful in developing markers that provide information about IR-induced phenomena such as the threshold dose.4,7,8 Furthermore, integrating data from combinations of such platforms, in the spirit of emerging systems biology, has given investigators the ability to reconstruct and analyze IR-responsive For assessment of the potential application of metabolomics to radiobiology, a UPLC-ESI-TOFMS metabolomic assay was established to evaluate the changes in small-molecule concentration that occur after γ-irradiation of cells in culture. The high-resolution of ultraperformance liquid chromatography (UPLC) and the accurate mass measurement of electrospray ionization time-of-flight mass spectrometry (ESI-TOFMS) were combined to generate protonated molecular ion matrices consisting of peak areas identified by specific m/ z values and retention times. The hydrophilic metabolomes of the lymphoid TK6 cell line and the hTERT-transformed fibroblast BJ cell line were analyzed following different doses of IR over a period of 16 h. The overall...

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Section: Resultssupporting

confidence: 89%

Section: Resultsmentioning

confidence: 99%