Activation of nucleus-independent signals triggered by N-methyl-N'-nitro-N- nitrosoguanidine / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To study the effect of MNNG on inducement of non-targeted mutation and activation of several cellular signal transduction pathways, and to determine whether the activation of these signaling pathways was dependent on the DNA-damage.</p><p><b>METHODS</b>Vero cells were enucleated by discontinuous density centrifugation. The PKA activities were measured by enzyme-linked immunosorbent assay. The status of cell membrane receptors was studied with immunofluorescent staining and confocal microscopy.</p><p><b>RESULT</b>In enucleated cytoplasts, MNNG-treatment increased PKA activity for about 2.3-fold in accordance with the 2.7-fold up-regulation of PKA activity in whole vero cells exposed to MNNG. The clustering of cell surface receptors of epidermal growth factor and tumor necrosis factor alpha was also observed in cells exposed to MNNG; this phenomenon was also found in enucleated cells.</p><p><b>CONCLUSION</b>The results indicate that the initiation of signal cascades induced by low concentration of MNNG might be associated with its interaction with cell surface receptors and/or direct activation of related signal proteins but not its DNA damage.</p>

Altered of zinc finger proteins expression in FL cells following benzo a pyrene treatment / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To understand benzo[a]pyrene (B[a]P) mediated cellular responses, and to provide clues to explore molecular mechanism of mutagenesis and carcinogenesis induced by B[a]P.</p><p><b>METHODS</b>Two-dimensional electrophoresis (2-DE) was used to investigate the protein expression levels of FL cells after B[a]P exposure, matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF-MS) combined with database search was applied to identify the differentially expressed proteins.</p><p><b>RESULT</b>Statistical analysis showed that the volumes of 47 protein spots were altered after B[a]P treatment (P<0.05) and 23 proteins were successfully identified, including zinc finger proteins, SWI/SNF related protein, Bromo domain containing domain and other proteins.</p><p><b>CONCLUSION</b>These affected proteins may be involved in the cellular responses to B[a]P exposure, and may mediate the B[a]P induced mutagenesis and carcinogenesis.</p>

Proteomic analysis of cellular responses to low concentration of N-methyl-N'-nitro-N-nitrosoguanidine in human amnion FL cells / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To investigate the protein profile after treatment of low concentration of N- methyl-N'-nitro-N-nitrosoguanidine (MNNG) in human FL cells.</p><p><b>METHODS</b>After MNNG treatment, whole cellular proteins were separated using two-dimensional gel electrophoresis and visualized by silver staining; the digitized images were analyzed with 2D analysis software. The differentially expressed protein spots were identified by matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF-MS).</p><p><b>RESULT</b>More than 60 proteins showed significant changes in MNNG-treated cells compared to control cells (DMSO treatment). There were 18 protein spots detected only after MNNG treatment, while 13 protein spots were detected only in the control cells. Moreover, the levels of another 31 proteins were either increased or decreased in MNNG-treated FL cells. And some of the proteins were identified by MALDI-TOF-MS.</p><p><b>CONCLUSION</b>There are significant alterations of protein profile after MNNG attack.</p>