• 05 DEC 05
    • 0

    Additions to the Breast cancer file on this list

    From Andy Davidson


    Just a couple of articles that when read together might make sense? Sorry; still batting on about EMR inducing nitric oxide, and it still keeps stitching things together. All I need is a full-time researcher to help me!


    http ://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=

    Effects of ELF magnetic fields on protein expression profile of human breast cancer cell MCF7.

    Li H, Zeng Q, Weng Y, Lu D, Jiang H, Xu Z.

    Bioelectromagnetics Laboratory, Zhejiang University, Hangzhou 310031, China.

    Extremely Low Frequency Magnetic Fields (ELF MF) has been considered as a “possible human carcinogen” by International Agency for Research on Cancer (IARC) while credible mechanisms of its carcinogenicity remain unknown. In this study, a proteomics approach was employed to investigate the changes of protein expression profile induced by ELF MF in human breast cancer cell line MCF7, in order to determine ELF MF-responsive proteins. MCF7 cells were exposed to 50 Hz, 0.4 mT ELF MF for 24 h and the changes of protein profile were examined using two dimensional electrophoresis. Up to 6 spots have been statistically significantly altered (their expression levels were changed at least 5 fold up or down) compared with sham-exposed group. 19 ones were only detected in exposure group while 19 ones were missing. Three proteins were identified by LC-IT Tandem MS as RNA binding protein regulatory subunit, Proteasome subunit beta type 7 precursor and Translationally Controlled Tumor Protein. Our finding showed that 50 Hz, 0.4 mT ELF MF alternates the protein profile of MCF7 cell and may affect many physiological functions of normal cell and 2-DE coupled with MS is a promising approach to elucidating cellular effects of electromagnetic fields.

    so MCF7 and nitric oxide?

    Nitric oxide nitrates tyrosine residues of tumor-suppressor p53 protein in MCF-7 cells.

    Chazotte-Aubert L, Hainaut P, Ohshima H.

    International Agency for Research on Cancer, 150 Cours Albert Thomas, Lyon Cedex 08, 69372, France.

    It has been reported that mammalian cells incubated with excess nitric oxide (NO) accumulate p53 protein but concomitantly this p53 loses its capacity for binding to its DNA consensus sequence. As nitration of tyrosine residues in various proteins has been shown to inhibit their functions, we examined whether NO nitrates tyrosine residues in p53 protein. MCF-7 cells expressing wild-type p53 were incubated with S-nitrosoglutathione for 4 h and cellular extracts were immunoprecipitated with an anti-p53 antibody. Western blot analyses of immunoprecipitates for p53 or for nitrotyrosine revealed low levels of nitrotyrosine in p53 from untreated cells. Incubation with 2 mM S-nitrosoglutathione induced a significant increase in the nitrotyrosine level in p53 protein compared to nontreated cells. These results suggest that excess NO produced in inflamed tissues could nitrate p53 protein, playing a role in carcinogenesis by impairing functions of this tumor-suppressor protein.

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