|References on AZD-7762:
1 . Aris SM, Pommier Y.Potentiation of the novel topoisomerase I inhibitor indenoisoquinoline LMP-400 by the cell checkpoint and Chk1-Chk2 inhibitor AZD7762.Cancer Res. 2012 Feb 15;72(4):979-89. Epub 2011 Dec 21.
Novel topoisomerase I (Top1) inhibitors are in clinical development to circumvent the drawbacks of camptothecins (CPT). Here, we report molecular investigations into LMP-400, an indenoisoquinoline Top1 inhibitor in phase 1 clinical trial, by itself and in combination with the cell-cycle checkpoint inhibitor AZD7762. We examined drug effects on DNA replication and killing of cancer cells and found that LMP-400 showed synergistic antiproliferative activity when combined with AZD7762 in human colon carcinoma cells. Inhibition of S-phase progression and bromodeoxyuridine incorporation were similarly induced by LMP-400 and CPT and were abrogated by AZD7762. Replication studied by single DNA molecule analyses and immunofluorescence microscopy (molecular combing) showed rapid inhibition of fork progression in response to LMP-400 treatment with subsequent recapitulation after AZD7762 addition. AZD7762 inhibited both the activation/autophosphosphorylation of Chk1 and Chk2 at nanomolar concentrations in LMP-400-treated cells. This potent dual inhibition of Chk1 and Chk2 by AZD7762 was below the drug concentrations required to abrogate cell-cycle inhibition and produce synergism with LMP-400. Also, the synergism was independent of Chk2 both in Chk2-complemented cells and Chk2 knockout cells, suggesting additional mechanisms for cell-cycle abrogation by AZD7762. Together, our findings show a rationale for combining cell-cycle checkpoint inhibitors with the novel non-CPT indenoisoquinoline Top1 inhibitors.
2 . Oza V, Ashwell S, Almeida L, Brassil P, Breed J, Deng C, Gero T, Grondine M, Horn C, Ioannidis S, Liu D, Lyne P, Newcombe N, Pass M, Read J, Ready S, Rowsell S, Su M, Toader D, Vasbinder M, Yu D, Yu Y, Xue Y, Zabludoff S, Janetka J.Discovery of checkpoint kinase inhibitor (S)-5-(3-fluorophenyl)-N-(piperidin-3-yl)-3-ureidothiophene-2-carboxamide (AZD7762) by structure-based design and optimization of thiophenecarboxamide ureas.J Med Chem. 2012 Jun 14;55(11):5130-42. Epub 2012 Jun 4.
Checkpoint kinases CHK1 and CHK2 are activated in response to DNA damage that results in cell cycle arrest, allowing sufficient time for DNA repair. Agents that lead to abrogation of such checkpoints have potential to increase the efficacy of such compounds as chemo- and radiotherapies. Thiophenecarboxamide ureas (TCUs) were identified as inhibitors of CHK1 by high throughput screening. A structure-based approach is described using crystal structures of JNK1 and CHK1 in complex with 1 and 2 and of the CHK1-3b complex. The ribose binding pocket of CHK1 was targeted to generate inhibitors with excellent cellular potency and selectivity over CDK1and IKKβ, key features lacking from the initial compounds. Optimization of 3b resulted in the identification of a regioisomeric 3-TCU lead 12a. Optimization of 12a led to the discovery of the clinical candidate 4 (AZD7762), which strongly potentiates the efficacy of a variety of DNA-damaging agents in preclinical models.
3 . Landau HJ, McNeely SC, Nair JS, Comenzo RL, Asai T, Friedman H, Jhanwar SC, Nimer SD, Schwartz GK.The Checkpoint Kinase Inhibitor AZD7762 Potentiates Chemotherapy-Induced Apoptosis of p53-Mutated Multiple Myeloma Cells.Mol Cancer Ther. 2012 Aug;11(8):1781-8. Epub 2012 May 31.
DNA cross-linking agents are frequently used in the treatment of multiple myeloma-generating lesions, which activate checkpoint kinase 1 (Chk1), a critical transducer of the DNA damage response. Chk1 activation promotes cell survival by regulating cell-cycle arrest and DNA repair following genotoxic stress. The ability of AZD7762, an ATP-competitive Chk1/2 inhibitor to increase the efficacy of the DNA-damaging agents bendamustine, melphalan, and doxorubicin was examined using four human myeloma cell lines, KMS-12-BM, KMS-12-PE, RPMI-8226, and U266B1. The in vitro activity of AZD7762 as monotherapy and combined with alkylating agents and the "novel" drug bortezomib was evaluated by studying its effects on cytotoxicity, signaling, and apoptotic pathways. The Chk1/2 inhibitor AZD7762 potentiated the antiproliferative effects of bendamustine, melphalan, and doxorubicin but not bortezomib in multiple myeloma cell lines that were p53-deficient. Increased γH2AX staining in cells treated with bendamustine or melphalan plus AZD7762 indicates a greater degree of DNA damage with combined therapy. Abrogation of the G(2)-M checkpoint by AZD7762 resulted in mitotic catastrophe with ensuing apoptosis evidenced by PARP and caspase-3 cleavage. In summary, the cytotoxic effects of bendamustine, melphalan and doxorubicin on p53-deficient multiple myeloma cell lines were enhanced by the coadministration of AZD7762. These data provide a rationale for testing these combinations in patients with relapsed and/or refractory multiple myeloma. Mol Cancer Ther; 11(8); 1781-8. ?2012 AACR.
4 . Ma Z, Yao G, Zhou B, Fan Y, Gao S, Feng X.The Chk1 inhibitor AZD7762 sensitises p53 mutant breast cancer cells to radiation in vitro and in vivo.Mol Med Report. 2012 Oct;6(4):897-903.
AZD7762, a novel checkpoint kinase 1 (Chk 1)inhibitor, has been proven to sensitize various tumor cells to DNA damage. However, whether or not AZD7762 sensitizes breast cancer cells to radiation has not been defined. In the present study, we aimed to demonstrate for the first time, that AZD7762 not only promotes radiation-induced apoptosis and mitotic catastrophe of p53 mutant T47D breast cancer cells in?vitro, but also delays their xenograft growth in response to radiation in?vivo. Our mechanistic study showed that AZD7762 treatment resulted in the abrogation of radiation-induced G2/M arrest and the inhibition of radiation damage repair as demonstrated by increased radiation-induced γH2AX expression and decreased RAD51 protein expression. These results suggest that AZD7762 may effectively abrogate radiation-induced G2/M arrest and inhibit radiation damage repair in conferring radiosensitivity on p53 mutant T47D breast cancer cells, by promoting radiation-induced apoptosis and mitotic catastrophe. The clinical application of AZD7762, as an adjuvant in the radiotherapy of breast cancers, should be further explored.
5 . Morgan MA et al Mechanism of radiosensitization by the Chk1/2 inhibitor AZD7762 involves abrogation of the G2 checkpoint and inhibition of homologous recombinational DNA repair. Cancer Res. 2010 Jun 15;70(12):4972-81.
The median survival for patients with locally advanced pancreatic cancer treated with gemcitabine and radiation is approximately 1 year. To develop improved treatment, we have combined a Chk1/2-targeted agent, AZD7762, currently in phase I clinical trials, with gemcitabine and ionizing radiation in preclinical pancreatic tumor models. We found that in vitro AZD7762 alone or in combination with gemcitabine significantly sensitized MiaPaCa-2 cells to radiation. AZD7762 inhibited Chk1 autophosphorylation (S296 Chk1), stabilized Cdc25A, and increased ATR/ATM-mediated Chk1 phosphorylation (S345 Chk1). Radiosensitization by AZD7762 was associated with abrogation of the G(2) checkpoint as well as with inhibition of Rad51 focus formation, inhibition of homologous recombination repair, and persistent gamma-H2AX expression. ...