title: Induction of apoptosis in estrogen receptor-negative breast cancer cells by natural and synthetic cyclopentenones: role of the IkappaB kinase/nuclear factor-kappaB pathway.
abstract: Nuclear factor-kappaB (NF-kappaB), a transcription factor with a critical role in promoting inflammation and cell survival, is constitutively activated in estrogen-receptor (ER)-negative breast cancer and is considered a potential therapeutic target for this type of neoplasia. We have previously demonstrated that cyclopentenone prostaglandins are potent inhibitors of NF-kappaB activation by inflammatory cytokines, mitogens, and viral infection, via direct binding and modification of the beta subunit of the IkappaB kinase complex (IKK). Herein, we describe the NF-kappaB-dependent anticancer activity of natural and synthetic cyclopentenone IKK inhibitors. We demonstrate that the natural cyclopentenone 15-deoxy-Delta(12,14)prostaglandin J(2) (15d-PGJ(2)) is a potent inhibitor of constitutive IkappaB-kinase and NF-kappaB activities in chemotherapy-resistant ER-negative breast cancer cells. 15d-PGJ(2)-induced inhibition of NF-kappaB function is rapidly followed by down-regulation of NF-kappaB-dependent antiapoptotic proteins cIAPs 1/2, Bcl-X(L), and cellular FLICE-inhibitory protein, leading to caspase activation and induction of apoptosis in breast cancer cells resistant to treatment with paclitaxel and doxorubicin. We then demonstrate that the cyclopentenone ring structure is responsible for these activities, and we identify a new synthetic cyclopentenone derivative, 3-tert-butyldimethylsilyloxy-5-(E)-iso-propylmethylenecyclopent-2-enone (CTC-35), as a potent NF-kappaB inhibitor with proapoptotic activity in ER-negative breast cancer cells. The results open new perspectives in the search for novel proapoptotic molecules effective in the treatment of cancers presenting aberrant NF-kappaB regulation.
authors.affiliation: Department of Biology, University of Rome Tor Vergata, Via della Ricerca Scientifica, 00133 Rome, Italy.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Ciucci
authors.forename: Patrizia
authors.initials: P
authors.lastname: Gianferretti
authors.forename: Roberto
authors.initials: R
authors.lastname: Piva
authors.forename: Thierry
authors.initials: T
authors.lastname: Guyot
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Snape
authors.forename: Stanley M
authors.initials: SM
authors.lastname: Roberts
authors.forename: M Gabriella
authors.initials: MG
authors.lastname: Santoro
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects*; D016718:Arachidonic Acid / Q000494:pharmacology; D001943:Breast Neoplasms / Q000378:metabolism / Q000473:pathology*; D020169:Caspases / Q000378:metabolism; D003517:Cyclopentanes / Q000737:chemistry / Q000494:pharmacology*; D015536:Down-Regulation / Q000187:drug effects; D019008:Drug Resistance, Neoplasm; D004354:Drug Screening Assays, Antitumor; D004789:Enzyme Activation / Q000187:drug effects; D006801:Humans; D051550:I-kappa B Kinase / Q000378:metabolism*; D051034:Inhibitor of Apoptosis Proteins / Q000378:metabolism; D016328:NF-kappa B / Q000378:metabolism*; D015230:Prostaglandin D2 / Q000031:analogs & derivatives* / Q000494:pharmacology; D011960:Receptors, Estrogen / Q000172:deficiency*; D014407:Tumor Cells, Cultured
chemical_list: C486212:(S)-4-tert-butyldimethylsilyloxy-2-cyclopenten-1-one; C477819:15-deoxyprostaglandin J2; D000970:Antineoplastic Agents; D003517:Cyclopentanes; D051034:Inhibitor of Apoptosis Proteins; D016328:NF-kappa B; D011960:Receptors, Estrogen; D016718:Arachidonic Acid; D051550:I-kappa B Kinase; D020169:Caspases; C013905:cyclopentenone; D015230:Prostaglandin D2