SR 57746A {1-[2-(naphth-2-yl) ethyl]-4-(3-trifluoromethylphenyl)-1,2,5,6-tetrahydropyridine hydrochloride} exhibits neurotrophic activities in vivo and in vitro. We used the rat pheochromocytoma PC12 cell line to investigate in vitro cellular changes induced by SR 57746A. A significant increase in the percentage of cells bearing neurite-like processes was obtained in cells treated by SR 57746A and nerve growth factor (NGF) compared with NGF treatment alone. SR 57746A added alone, however, had no effect on morphogenesis or on survival of cells in serum-free medium. In contrast, SR 57746A induced a ''priming'' effect on PC12 cells for neurite outgrowth within 6 h of addition of the protein tyrosine kinase inhibitor genistein. An increase in alpha-actinin content resulted from treatment with SR 57746A. Expression of NGF-mediated acetylcholinesterase and choline acetyltransferase was enhanced within 5 days by SR 57746A. The molecule also induced rapid F-actin redistribution. Within 2 min of incubation, outgrowth of F-actin-containing filopodia was clearly visible at the cell periphery, as previously shown with NGF. it is interesting that this effect of SR 57746A could be mimicked by protein tyrosine kinase inhibitors and abolished by preincubation with sodium orthovanadate, a protein tyrosine phosphatase inhibitor.
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Mitomycin C (1a) is considered to be the prototypical bioreductive alkylating agent. Among the numerous reductive procedures employed for the in vitro activation of mitomycin C, incremental addition of Na2S2O4 has emerged as the method of choice for generating high yields of mitomycin C-DNA adducts. The major products and distinguishing features of the incremental addition Na2S2O4-Mitomycin C reductive processes in water (pH 7.4) in the absence of DNA are reported. Key observations included (1) rapid and efficient consumption of mitomycin C, (2) production of high amounts of 7-aminomitosane-9a-sulfonate (1b) in the early stages of the reaction, and (3) generation of significant amounts of C(1) and C(10) sulfonate adducts. The complexity of this transformation has been attributed in part to HSO3-, a byproduct of the Na2S2O4 reduction process. Use of buffered methanol solutions (''pH'' 7.4) in place of water simplified the product profile. The poor solubility of Na2S2O4 and NaHSO3 in methanol produced only trace amounts of mitosene sulfonate adducts. There were significant differences between product profiles for the incremental addition Na2S2O4 procedure versus a protocol in which the equivalent amount of Na2S2O4 was added in a single shot. First, higher amounts of C(1) electrophilic versus C(1) nucleophilic products were observed using the single shot technique. Second, C(1) sulfonate adducts composed a larger amount of the C(1) nucleophilic product pool when the Na2S2O4 was added using the single shot protocol than with the incremental addition method. Third, higher amounts of 1a were converted to C(1), C(10) fully functionalized mitosene adducts using the incremental procedure. Select auxiliary experiments provided additional information concerning the Na2S2O-mediated mitomycin C reductive process. Examination of the reactivity of key C(1), C(9a), and C(10) mitomycin sulfonate products demonstrated that 7-aminomitosane-9a-sulfonate (1b) was efficiently converted to C(1)- and C(10)-functionalized mitosenes under reductive conditions, whereas mitosene C(1) and C(10) sulfonates did not undergo displacement reactions and hence did not function as viable alkylating agents. On the basis of these cumulative studies, we suggest the likely mechanism for the Na2S2O4-mediated mitomycin C reductive process and the beneficial properties accrued by the use of the incremental addition technique. These notions are discussed in light of the pathway that may be operative in in vitro mitomycin C-DNA bonding transformations.
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTOn the origins of the DNA sequence selectivity of mitomycin monoalkylation transformationsHarold Kohn, Ven Shun Li, Pascal Schiltz, and Moon Shong TangCite this: J. Am. Chem. Soc. 1992, 114, 23, 9218–9220Publication Date (Print):November 1, 1992Publication History Published online1 May 2002Published inissue 1 November 1992https://doi.org/10.1021/ja00049a082RIGHTS & PERMISSIONSArticle Views71Altmetric-Citations45LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (1 MB) Get e-AlertsSupporting Info (1)»Supporting Information Supporting Information Get e-Alerts
Sodium dithionite is the reagent of choice for the reductiue activation of mitomycin C in the presence of DNA. No comprehensive study of this transformation in the absence of DNA has appeared. The major products of this reaction have been determined and the key parameters governing this transformation identified.
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTReductively activated mitomycin C: an efficient trapping reagent for electrophilesPascal Schiltz and Harold KohnCite this: J. Am. Chem. Soc. 1992, 114, 20, 7958–7959Publication Date (Print):September 1, 1992Publication History Published online1 May 2002Published inissue 1 September 1992https://pubs.acs.org/doi/10.1021/ja00046a079https://doi.org/10.1021/ja00046a079research-articleACS PublicationsRequest reuse permissionsArticle Views65Altmetric-Citations9LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts