Seliciclib/Roscovitine

[Rich66]

(Cdk2 inhib, Er resistance reverser, Circadian clock modulator)





http://en.wikipedia.org/wiki/Seliciclib:


R-roscovitine (Seliciclib or CYC202) is a trial drug in the family of pharmacological cyclin-dependent kinase (CDK) inhibitors that preferentially inhibit multiple enzyme targets including CDK2, CDK7 and CDK9, which alter the growth phase or state within the cell cycle of treated cells. Seliciclib is being developed by Cyclacel.
Seliciclib is being researched for the treatment of non-small cell lung cancer (NSCLC), leukemia, HIV infection, herpes simplex infection, and the mechanisms of chronic inflammation disorders.
Seliciclib is a 2,6,9-substituted purine analog. Its structure in complex with CDK2 was determined in 1996.^[1] Seliciclib inhibits CDK2/E, CDK2/A, CDK7 and CDK9.^[2]
Uses

Seliciclib has been found to produce apoptosis in treated cancerous cells of non-small cell lung cancer (NSCLC) and other cancers. Seliciclib has previously undergone Phase IIa clinical trials, in 240 NSCLC patients as a combined dose with existing first- and second-line treatments.^[2][3] In the current APPRAISE trial, the research drug is undergoing Phase IIb clinical trial as a monotherapy for NSCLC in third-line patients.^[4] The side-effects reported in Phase I trials of Seliciclib for NSCLC were "nausea, vomiting, transient elevations in serum creatinine and liver function parameters and transient hypokalemia".^[3]





CDK2 Inhibitor Restores Letrozole's Growth Inhibition

After confirming that the LMW forms of cyclin E suppress the anti-proliferative effects of letrozole, the researchers examined whether a CDK2 inhibitor could reverse the drug resistance in the unresponsive breast cancer cells.
"We challenged the aromatase-overexpressing cells with either the wild-type or the low forms of cyclin E and then treated them with the CDK2 inhibitor roscovitine," Keyomarsi said. "When we did that, we could kill all the cells."
The researchers also looked back at the results of another ongoing study from their group in which 128 ER+ breast cancer patients were treated with an aromatase inhibitor. "Of those, 100 expressed normal levels of wild-type cyclin E, and 28 overexpressed the low forms," Keyomarsi said. "When we looked at recurrence, three of the hundred with wild-type cyclin E had experienced a recurrence compared to four of the twenty-eight with the low forms. That in itself tells us there is a huge difference between the two groups of patients based on the pattern of expression of normal versus low forms of cyclin E."
Of the seven patients who had a recurrence, six had high levels of cyclin E activity. Keyomarsi noted that these patients can be treated with a CDK2 inhibitor, which is now clinically available.
"I believe that in the very near future we will be able to take advantage of the knowledge we now have about the low forms of cyclin E, and identify the patients who have these forms and devise a personalized treatment," Keyomarsi added.
This research was supported by National Institutes of Health grant CA87458 and National Cancer Institute grant P50CA116199, as well as funds from the Clayton Foundation.
Keyomarsi's co-authors on the all-M. D. Anderson study include: Said Akli, Ph.D., Tuyen Bui, Anna Biernacka, M.D. all of the Department of Experimental Radiation Oncology; Kelly K. Hunt, M.D.; and Hannah Wingate, Ph.D., Department of Surgical Oncology; Stacy Moulder, M.D., Department of Breast Medical Oncology; and Susan L. Tucker, Ph.D., Department of Bioinformatics and Computational Biology.





Cell Cycle. 2007 Dec 15;6(24):3114-31. Epub 2007 Oct 5.
The cyclin-dependent kinase inhibitor seliciclib (R-roscovitine; CYC202) decreases the expression of mitotic control genes and prevents entry into mitosis.

Whittaker SR, Te Poele RH, Chan F, Linardopoulos S, Walton MI, Garrett MD, Workman P.
Cancer Research UK Centre for Cancer Therapeutics, The Institute of Cancer Research, Haddow Laboratories, Sutton, Surrey, UK.
The cyclin-dependent kinase (CDK) inhibitor seliciclib (R-roscovitine, CYC202) shows promising antitumor activity in preclinical models and is currently undergoing phase II clinical trials. Inhibition of the CDKs by seliciclib could contribute to cell cycle arrest and apoptosis seen with the drug. However, it is common for drugs to exert multiple effects on gene expression and biochemical pathways. To further our understanding of the molecular pharmacology of seliciclib, we employed cDNA microarrays to determine changes in gene expression profiles induced by the drug in HT29 human colon cancer cells. Concentrations of seliciclib were used that inhibited RB phosphorylation and cell proliferation. An increase in the mRNA expression for CJUN and EGR1 was confirmed by Western blotting, consistent with activation of the ERK1/2 MAPK pathway by seliciclib. Transcripts of key genes required for the progression through mitosis showed markedly reduced expression, including Aurora-A/B (AURK-A/B), Polo-like kinase (PLK), cyclin B2 (CCNB2), WEE1 and CDC25C. Reduced expression of these mitotic genes was also seen at the protein level. siRNA-mediated depletion of Aurora-A protein led to an arrest of cells in the G(2)/M phase, consistent with the effects of seliciclib treatment. Inhibition of mitotic entry following seliciclib treatment was indicated by a reduction of histone H3 phosphorylation, which is catalyzed by Aurora-B, and by decreased expression of mitotic markers, including phospho-protein phosphatase 1 alpha. The results indicate a potential mechanism through which seliciclib prevents entry into mitosis. Gene expression profiling has generated hypotheses that led to an increase in our knowledge of the cellular effects of seliciclib and could provide potential pharmacodynamic or response biomarkers for use in animal models and clinical trials.

PMID: 18075315 [PubMed - indexed for MEDLINE]




Cell Cycle. 2007 Dec 15;6(24):3114-31. Epub 2007 Oct 5.
The cyclin-dependent kinase inhibitor seliciclib (R-roscovitine; CYC202) decreases the expression of mitotic control genes and prevents entry into mitosis.

Whittaker SR, Te Poele RH, Chan F, Linardopoulos S, Walton MI, Garrett MD, Workman P.
Cancer Research UK Centre for Cancer Therapeutics, The Institute of Cancer Research, Haddow Laboratories, Sutton, Surrey, UK.
The cyclin-dependent kinase (CDK) inhibitor seliciclib (R-roscovitine, CYC202) shows promising antitumor activity in preclinical models and is currently undergoing phase II clinical trials. Inhibition of the CDKs by seliciclib could contribute to cell cycle arrest and apoptosis seen with the drug. However, it is common for drugs to exert multiple effects on gene expression and biochemical pathways. To further our understanding of the molecular pharmacology of seliciclib, we employed cDNA microarrays to determine changes in gene expression profiles induced by the drug in HT29 human colon cancer cells. Concentrations of seliciclib were used that inhibited RB phosphorylation and cell proliferation. An increase in the mRNA expression for CJUN and EGR1 was confirmed by Western blotting, consistent with activation of the ERK1/2 MAPK pathway by seliciclib. Transcripts of key genes required for the progression through mitosis showed markedly reduced expression, including Aurora-A/B (AURK-A/B), Polo-like kinase (PLK), cyclin B2 (CCNB2), WEE1 and CDC25C. Reduced expression of these mitotic genes was also seen at the protein level. siRNA-mediated depletion of Aurora-A protein led to an arrest of cells in the G(2)/M phase, consistent with the effects of seliciclib treatment. Inhibition of mitotic entry following seliciclib treatment was indicated by a reduction of histone H3 phosphorylation, which is catalyzed by Aurora-B, and by decreased expression of mitotic markers, including phospho-protein phosphatase 1 alpha. The results indicate a potential mechanism through which seliciclib prevents entry into mitosis. Gene expression profiling has generated hypotheses that led to an increase in our knowledge of the cellular effects of seliciclib and could provide potential pharmacodynamic or response biomarkers for use in animal models and clinical trials.

PMID: 18075315 [PubMed - indexed for MEDLINE]




Eur J Immunol. 2010 Feb 1. [Epub ahead of print]
The cyclin-dependent kinase inhibitor R-roscovitine down-regulates Mcl-1 to override pro-inflammatory signalling and drive neutrophil apoptosis.

Leitch AE, Riley NA, Sheldrake T, Festa M, Fox S, Duffin R, Haslett C, Rossi AG.
MRC Centre for Inflammation Research, The Queen's Medical Research Institute, University of Edinburgh Medical School, 47 Little France Crescent, Edinburgh, Scotland, UK.
Successful resolution of inflammation requires inflammatory cells such as neutrophils to undergo apoptosis prior to non-inflammatory phagocytosis by professional phagocytes. Recently, cyclin-dependent kinase (CDK) inhibitors (e.g. R-roscovitine) have been shown to induce neutrophil apoptosis and enhance the resolution of inflammation. Interestingly, NF-kappaB and MAPK pathways and key endogenous survival proteins (typified by Mcl-1) are involved in the regulation of neutrophil apoptosis and, in cancer-cell lines, have been implicated as possible targets of CDK inhibitors. Here we demonstrate that R-roscovitine over-rides TNF-alpha and LPS-induced survival (determined by morphological examination and binding of fluorescently labelled annexin-V) of isolated peripheral blood neutrophils. This effect did not appear to be mediated via effects on early markers of neutrophil activation (e.g., surface marker expression, shape change, aggregation and superoxide anion generation), by direct inhibition of NF-kappaB activation (assessed by cytoplasmic IkappaBalpha proteolysis and NF-kappaB p65 subunit translocation) and ERK activation (determined by specific ERK phosphorylation) but due to down-regulation (at protein and mRNA level) of the survival protein Mcl-1 but not the pro-apoptotic bcl-2 homologue Bim. These findings suggest that key endogenous survival proteins may be the targets of CDK inhibitors and consequently may be of critical importance in the resolution of inflammation.

PMID: 20127676 [PubMed - as supplied by publisher]




Chronobiol Int. 2009 Aug;26(6):1169-88.
Liver circadian clock, a pharmacologic target of cyclin-dependent kinase inhibitor seliciclib.

Iurisci I, Filipski E, Sallam H, Harper F, Guettier C, Maire I, Hassan M, Iacobelli S, Lévi F.
INSERM, U 776 Rythmes biologiques et cancers, Hôp. P. Brousse, Villejuif, F-94807, France.
Circadian disruption accelerates malignant growth and shortens survival, both in experimental tumor models and cancer patients. In previous experiments, tumor circadian disruption was rescued with seliciclib, an inhibitor of cyclin-dependent kinases (CDKs). This effect occurred at a selective dosing time and was associated with improved antitumor activity. In the current study, seliciclib altered robust circadian mRNA expression of the clock genes Rev-erb alpha, Per2, and Bmal1 in mouse liver following dosing at zeitgeber time (ZT) 3 (i.e., 3 h after the onset of the 12 h light span), when mice start to rest, but not at ZT19, near the middle of the 12 h dark span, when mice are most active. However, liver exposure to seliciclib, as estimated by the liver area under the concentration x time curve (AUC), was approximately 80% higher at ZT19 than at ZT3 (p = 0.049). Circadian clock disruption was associated with increased serum liver enzymes and modified glycogen distribution in hepatocytes, as revealed by biochemical determinations and optic and electronic microscopy. The extent of increase in liver enzymes was most pronounced following dosing at ZT3, as compared to ZT19 (p < 0.04). Seliciclib further up-regulated the transcriptional activity of c-Myc, a cell cycle gene that promotes cell cycle entry and G1-S transition (p < 0.001), and down-regulated that of Wee1, which gates cell cycle transition from G2 to M (p < 0.001). These effects did not depend upon drug dosing time. Overall, the results suggest the circadian time of seliciclib delivery is more critical than the amount of drug exposure in determining its effects on the circadian clock. Seliciclib-induced disruption of the liver molecular clock could account for liver toxicity through the resulting disruption of clock-controlled detoxification pathways. Modifications of cell cycle gene expression in the liver likely involve other mechanisms. Circadian clocks represent relevant targets to consider for optimization of therapeutic schedules of CDK inhibitors.

PMID: 19731111 [PubMed - indexed for MEDLINE]


Cancer Res. 2006 Nov 15;66(22):10720-8.
Improved tumor control through circadian clock induction by Seliciclib, a cyclin-dependent kinase inhibitor.

Iurisci I, Filipski E, Reinhardt J, Bach S, Gianella-Borradori A, Iacobelli S, Meijer L, Lévi F.
Institut National de la Santé et de la Recherche Médicale, U776 "Rythmes Biologiques et Cancers," Hôpital Paul Brousse, Villejuif Cedex, France.
The circadian timing system and the cell division cycle are frequently deregulated in cancer. The therapeutic relevance of the reciprocal interactions between both biological rhythms was investigated using Seliciclib, a cyclin-dependent kinase (CDK) inhibitor (CDKI). Mice bearing Glasgow osteosarcoma received Seliciclib (300 mg/kg/d orally) or vehicle for 5 days at Zeitgeber time (ZT) 3, 11, or 19. On day 6, tumor mRNA 24-hour expression patterns were determined for clock genes (Per2, Rev-erbalpha, and Bmal1) and clock-controlled cell cycle genes (c-Myc, Wee1, cyclin B1, and CDK1) with quantitative reverse transcription-PCR. Affinity chromatography on immobilized Seliciclib identified CDK1/CDK2 and extracellular signal-regulated kinase (ERK) 1/ERK2, CDK7/CDK9, and casein kinase CK1epsilon as Seliciclib targets, which respectively regulate cell cycle, transcription, and circadian clock in Glasgow osteosarcoma. Seliciclib reduced tumor growth by 55% following dosing at ZT3 or ZT11 and by 35% at ZT19 compared with controls (P < 0.001). Tolerability was also best at ZT3. Mean transcriptional activity of Rev-erbalpha, Per2, and Bmal1 was arrhythmic in the tumors of untreated mice. Seliciclib induced rhythmic clock gene expression patterns with physiologic phase relations only after ZT3 dosing. c-Myc and Wee1 mRNAs displayed synchronous circadian rhythms in the tumors of control mice receiving vehicle only but not in those of mice given the drug. Seliciclib further enhanced Wee1 expression irrespective of dosing time, an effect that reinforced G(2)-M gating. Seliciclib also inhibited CK1epsilon, which determines circadian period length. The coordination of clock gene expression patterns in tumor cells was associated with best antitumor activity of Seliciclib. The circadian clock and its upstream regulators represent relevant targets for CDKIs.

PMID: 17108108 [PubMed - indexed for MEDLINE]