5-alpha-reductase

2013年2月4日星期一

The anticancer multi-kinase inhibitor dovitinib also targets topoisomerase I and topoisomerase II.

The anticancer multi-kinase inhibitor dovitinib also targets topoisomerase I and topoisomerase II.

Biochem Pharmacol. 2012 Dec 15;84(12):1617-26

Authors: Hasinoff BB, Wu X, Nitiss JL, Kanagasabai R, Yalowich JC

Abstract
Dovitinib (TKI258/CHIR258) is a multi-kinase inhibitor in phase III development for the treatment of several cancers. Dovitinib is a benzimidazole-quinolinone compound that structurally resembles the bisbenzimidazole minor groove binding dye Hoechst 33258. Dovitinib bound to DNA as shown by its ability to increase the DNA melting temperature and by increases in its fluorescence spectrum that occurred upon the addition of DNA. Molecular modeling studies of the docking of dovitinib into an X-ray structure of a Hoechst 33258-DNA complex showed that dovitinib could reasonably be accommodated in the DNA minor groove. Because DNA binders are often topoisomerase I (EC 5.99.1.2) and topoisomerase II (EC 5.99.1.3) inhibitors, the ability of dovitinib to inhibit these DNA processing enzymes was also investigated. Dovitinib inhibited the catalytic decatenation activity of topoisomerase II?. It also inhibited the DNA-independent ATPase activity of yeast topoisomerase II which suggested that it interacted with the ATP binding site. Using isolated human topoisomerase II?, dovitinib stabilized the enzyme-cleavage complex and acted as a topoisomerase II? poison. Dovitinib was also found to be a cellular topoisomerase II poison in human leukemia K562 cells and induced double-strand DNA breaks in K562 cells as evidenced by increased phosphorylation of H2AX. Finally, dovitinib inhibited the topoisomerase I-catalyzed relaxation of plasmid DNA and acted as a cellular topoisomerase I poison. In conclusion, the cell growth inhibitory activity and the anticancer activity of dovitinib may result not only from its ability to inhibit multiple kinases, but also, in part, from its ability to target topoisomerase I and topoisomerase II.

PMID: 23041231 [PubMed - indexed for MEDLINE]

ecdysone chir-258 dovitinib

Pharmacotherapy of Zollinger-Ellison syndrome.

Pharmacotherapy of Zollinger-Ellison syndrome.

Expert Opin Pharmacother. 2013 Jan 30;

Authors: Ito T, Igarashi H, Uehara H, Jensen RT

Abstract
Introduction: The role of pharmacotherapy in the management of patients with Zollinger-Ellison syndrome (ZES) is often equated with the medical management of acid hypersecretion. However, pharmacotherapy is also increasingly involved in the other management areas of these patients. Areas covered: This paper reviews the role of pharmacotherapy in all aspects of the management of patients with ZES. Newer aspects are emphasized. This includes the difficulty of diagnosing ZES in patients taking proton pump inhibitors. Also covered is the role of pharmacotherapy in controlling acid hypersecretion and other hormonal hypersecretory states these patients may develop, including hyperparathyroidism in patients with multiple endocrine neoplasia type 1 and ZES; tumor localization; and the treatment of advanced metastatic disease. The last includes chemotherapy, liver-directed therapies, biotherapy (somatostatin/interferon), peptide radio-receptor therapy and molecular-targeted therapies including the use of mTor inhibitors (everolimus) and tyrosine kinase inhibitors (sunitinib). Expert opinion: Pharmacotherapy is now involved in all aspects of the management of patients with ZES, with the result that ZES has progressed from being considered an entirely surgical disease initially to the present where medical treatment plays a major role in almost all aspects of the management of these patients.

PMID: 23363383 [PubMed - as supplied by publisher]

c-met inhibitors zm-447439 rad001

2013年2月3日星期日

Rationale and design of MARQUEE: a phase III, randomized, double-blind study of tivantinib plus erlotinib versus placebo plus erlotinib in previously treated patients with locally advanced or metastatic, nonsquamous, non-small-cell lung cancer.

Rationale and design of MARQUEE: a phase III, randomized, double-blind study of tivantinib plus erlotinib versus placebo plus erlotinib in previously treated patients with locally advanced or metastatic, nonsquamous, non-small-cell lung cancer.

Clin Lung Cancer. 2012 Sep;13(5):391-5

Authors: Scagliotti GV, Novello S, Schiller JH, Hirsh V, Sequist LV, Soria JC, von Pawel J, Schwartz B, Von Roemeling R, Sandler AB

Abstract
We present the rationale and design for MARQUEE, a phase III, randomized, double-blind, placebo-controlled study of ARQ 197 plus erlotinib versus placebo plus erlotinib in previously treated subjects with locally advanced or metastatic, nonsquamous, non-small-cell lung cancer (NSCLC). The design of MARQUEE is based on preclinical data, the current understanding of the role of cellular N-methyl-N'-nitroso-guanidine human osteosarcoma (MNNG HOS) transforming gene (MET) in NSCLC, and clinical data from a randomized phase II study. The available evidence suggests that dual inhibition of MET and the epidermal growth factor receptor (EGFR) may overcome resistance to EGFR inhibitors. In the phase II study, the combination of tivantinib plus erlotinib significantly improved progression-free survival (PFS) and overall survival (OS) compared with placebo plus erlotinib in the subset of patients with nonsquamous histology, a population enriched for MET overexpression. The primary endpoint in MARQUEE is OS. Secondary and exploratory objectives include determination of PFS, OS in molecular subgroups (defined by EGFR and KRAS mutation status, amplification or overexpression of MET, and serum hepatocyte growth factor), and safety. All patients will be tested for biomarkers, and the results will provide a wealth of information on the role of tivantinib in treating nonsquamous NSCLC.

PMID: 22440336 [PubMed - indexed for MEDLINE]

c-met inhibitors zm-447439 rad001

What goes up must come down: transcription factors have their say in making ecdysone pulses.

What goes up must come down: transcription factors have their say in making ecdysone pulses.

Curr Top Dev Biol. 2013;103:35-71

Authors: Ou Q, King-Jones K

Abstract
Insect metamorphosis is one of the most fascinating biological processes in the animal kingdom. The dramatic transition from an immature juvenile to a reproductive adult is under the control of the steroid hormone ecdysone, also known as the insect molting hormone. During Drosophila development, periodic pulses of ecdysone are released from the prothoracic glands, upon which the hormone is rapidly converted in peripheral tissues to its biologically active form, 20-hydroxyecdysone. Each hormone pulse has a unique profile and causes different developmental events, but we only have a rudimentary understanding of how the timing, amplitude, and duration of a given pulse are controlled. A key component involved in the timing of ecdysone pulses is PTTH, a brain-derived neuropeptide. PTTH stimulates ecdysone production through a Ras/Raf/ERK signaling cascade; however, comparatively little is known about the downstream targets of this pathway. In recent years, it has become apparent that transcriptional regulation plays a critical role in regulating the synthesis of ecdysone, but only one transcription factor has a well-defined link to PTTH. Interestingly, many of the ecdysteroidogenic transcription factors were originally characterized as primary response genes in the ecdysone signaling cascade that elicits the biological responses to the hormone in target tissues. To review these developments, we will first provide an overview of the transcription factors that act in the Drosophila ecdysone regulatory hierarchy. We will then discuss the roles of these transcriptional regulators in controlling ecdysone synthesis. In the last section, we will briefly outline transcription factors that likely have roles in regulating ecdysone synthesis but have not been formally identified as downstream effectors of ecdysone.

PMID: 23347515 [PubMed - in process]

dovitinib dna-pk coxinhibitors

Homologous chromosomes move and rapidly initiate contact at the sites of double-strand breaks in genes in G 0-phase human cells.

Homologous chromosomes move and rapidly initiate contact at the sites of double-strand breaks in genes in G 0-phase human cells.

Cell Cycle. 2013 Jan 31;12(4)

Authors: Gandhi M, Evdokimova VN, Cuenco KT, Bakkenist CJ, Nikiforov YE

Abstract
We recently reported that homologous chromosomes make contact at the sites of double-strand breaks (DSBs) induced by ionizing radiation (IR) and the restriction endonuclease I-PpoI in G 0/G 1-phase somatic human cells. The contact involves short segments of homologous chromosomes and is centered on a DSB that occurs in a gene; contact does not occur at a DSB in intergenic DNA. Contact between homologous chromosomes is abrogated by inhibition of transcription and requires the kinase activity of ATM, but not DNA-PK. Here, we report additional insights into the mechanism underlying this novel phenomenon. We identify four patterns of homologous chromosome contact, and show that contact between homologous arms, but not centrosomes, is induced by IR. Significantly, we demonstrate that contact is induced by IR in non-proliferating, G 0-phase human cells derived from tissue explants. Finally, we show that contact between homologous chromosomes is detectable as early as 5 min after IR. These results point to the existence of a mechanism that rapidly localizes homologous chromosome arms at sites of DSBs in genes in G 0-phase human cells.

PMID: 23370393 [PubMed - as supplied by publisher]

rad001 ecdysone chir-258

Pharmacotherapy of Zollinger-Ellison syndrome.

Pharmacotherapy of Zollinger-Ellison syndrome.

Expert Opin Pharmacother. 2013 Jan 30;

Authors: Ito T, Igarashi H, Uehara H, Jensen RT

PMID: 23363383 [PubMed - as supplied by publisher]

coxinhibitors c-met inhibitors zm-447439

Homologous chromosomes move and rapidly initiate contact at the sites of double-strand breaks in genes in G 0-phase human cells.

Homologous chromosomes move and rapidly initiate contact at the sites of double-strand breaks in genes in G 0-phase human cells.

Cell Cycle. 2013 Jan 31;12(4)

Authors: Gandhi M, Evdokimova VN, Cuenco KT, Bakkenist CJ, Nikiforov YE

PMID: 23370393 [PubMed - as supplied by publisher]

c-met inhibitors zm-447439 rad001

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