title: Nitric oxide synthase and breast cancer: role of TIMP-1 in NO-mediated Akt activation.
abstract: Prediction of therapeutic response and cancer patient survival can be improved by the identification of molecular markers including tumor Akt status. A direct correlation between NOS2 expression and elevated Akt phosphorylation status has been observed in breast tumors. Tissue inhibitor matrix metalloproteinase-1 (TIMP-1) has been proposed to exert oncogenic properties through CD63 cell surface receptor pathway initiation of pro-survival PI3k/Akt signaling. We employed immunohistochemistry to examine the influence of TIMP-1 on the functional relationship between NOS2 and phosphorylated Akt in breast tumors and found that NOS2-associated Akt phosphorylation was significantly increased in tumors expressing high TIMP-1, indicating that TIMP-1 may further enhance NO-induced Akt pathway activation. Moreover, TIMP-1 silencing by antisense technology blocked NO-induced PI3k/Akt/BAD phosphorylation in cultured MDA-MB-231 human breast cancer cells. TIMP-1 protein nitration and TIMP-1/CD63 co-immunoprecipitation was observed at NO concentrations that induced PI3k/Akt/BAD pro-survival signaling. In the survival analysis, elevated tumor TIMP-1 predicted poor patient survival. This association appears to be mainly restricted to tumors with high NOS2 protein. In contrast, TIMP-1 did not predict poor survival in patient tumors with low NOS2 expression. In summary, our findings suggest that tumors with high TIMP-1 and NOS2 behave more aggressively by mechanisms that favor Akt pathway activation.
authors.affiliation: Radiation Biology Branch, National Cancer Institute, Bethesda, Maryland, United States of America. ridnourl@mail.nih.gov
authors.forename: Lisa A
authors.initials: LA
authors.lastname: Ridnour
authors.forename: Kimberly M
authors.initials: KM
authors.lastname: Barasch
authors.forename: Alisha N
authors.initials: AN
authors.lastname: Windhausen
authors.forename: Tiffany H
authors.initials: TH
authors.lastname: Dorsey
authors.forename: Michael M
authors.initials: MM
authors.lastname: Lizardo
authors.forename: Harris G
authors.initials: HG
authors.lastname: Yfantis
authors.forename: Dong H
authors.initials: DH
authors.lastname: Lee
authors.forename: Christopher H
authors.initials: CH
authors.lastname: Switzer
authors.forename: Robert Y S
authors.initials: RY
authors.lastname: Cheng
authors.forename: Julie L
authors.initials: JL
authors.lastname: Heinecke
authors.forename: Ernst
authors.initials: E
authors.lastname: Brueggemann
authors.forename: Harry B
authors.initials: HB
authors.lastname: Hines
authors.forename: Chand
authors.initials: C
authors.lastname: Khanna
authors.forename: Sharon A
authors.initials: SA
authors.lastname: Glynn
authors.forename: Stefan
authors.initials: S
authors.lastname: Ambs
authors.forename: David A
authors.initials: DA
authors.lastname: Wink
mesh_terms: D001943:Breast Neoplasms / Q000201:enzymology*; D018955:CD36 Antigens / Q000096:biosynthesis; D004789:Enzyme Activation; D005260:Female; D015971:Gene Expression Regulation, Enzymologic; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D018613:Microscopy, Confocal / Q000379:methods; D009569:Nitric Oxide / Q000378:metabolism*; D019001:Nitric Oxide Synthase / Q000502:physiology*; D016376:Oligonucleotides, Antisense / Q000235:genetics; D010766:Phosphorylation; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism*; D015398:Signal Transduction; D019715:Tissue Inhibitor of Metalloproteinase-1 / Q000502:physiology*; D016896:Treatment Outcome
chemical_list: D018955:CD36 Antigens; D016376:Oligonucleotides, Antisense; C560822:TIMP1 protein, human; D019715:Tissue Inhibitor of Metalloproteinase-1; D009569:Nitric Oxide; D019001:Nitric Oxide Synthase; D051057:Proto-Oncogene Proteins c-akt