Cyclin-dependent kinases (CDKs) are key regulators of the cell cycle and RNA polymerase II mediated transcription. Several pharmacological CDK inhibitors are currently in clinical trials as potential cancer therapeutics and some of them also exhibit antiviral effects. Olomoucine II and roscovitine, purine-based inhibitors of CDKs, were described as effective antiviral agents that inhibit replication of a broad range of wild type human viruses. Olomoucine II and roscovitine show high selectivity for CDK7 and CDK9, with important functions in the regulation of RNA polymerase II transcription. RNA polymerase II is necessary for viral transcription and following replication in cells. We analyzed the effect of inhibition of CDKs by olomoucine II on gene expression from viral promoters and compared its effect to widely-used roscovitine. We found that both roscovitine and olomoucine II blocked the phosphorylation of RNA polymerase II C-terminal domain. However the repression of genes regulated by viral promoters was strongly dependent on gene localization. Both roscovitine and olomoucine II inhibited expression only when the viral promoter was not integrated into chromosomal DNA. In contrast, treatment of cells with genome-integrated viral promoters increased their expression even though there was decreased phosphorylation of the C-terminal domain of RNA polymerase II. To define the mechanism responsible for decreased gene expression after pharmacological CDK inhibitor treatment, the level of mRNA transcription from extrachromosomal DNA was determined. Interestingly, our results showed that inhibition of RNA polymerase II C-terminal domain phosphorylation increased the number of transcribed mRNAs. However, some of these mRNAs were truncated and lacked polyadenylation, which resulted in decreased translation. These results suggest that phosphorylation of RNA polymerase II C-terminal domain is critical for linking transcription and posttrancriptional processing of mRNA expressed from extrachromosomal DNA.

• MeSH
• buněčné linie MeSH
• buněčný cyklus účinky léků   MeSH
• Cercopithecus aethiops MeSH
• cyklin-dependentní kinasy antagonisté a inhibitory   MeSH
• DNA virů MeSH
• fosforylace účinky léků   MeSH
• inhibitory proteinkinas farmakologie   MeSH
• ledviny účinky léků   metabolismus   MeSH
• lidé MeSH
• posttranskripční úpravy RNA účinky léků   MeSH
• promotorové oblasti (genetika) účinky léků   MeSH
• puriny farmakologie   MeSH
• RNA-polymerasa II genetika   metabolismus   MeSH
• roskovitin MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• cyklin-dependentní kinasy MeSH
• DNA virů MeSH
• inhibitory proteinkinas MeSH
• olomoucine II MeSH Prohlížeč
• puriny MeSH
• RNA-polymerasa II MeSH
• roskovitin MeSH

Purine cyclin-dependent kinase inhibitors have been recognized as promising candidates for the treatment of various cancers; nevertheless, data regarding interaction of these substances with drug efflux transporters is still lacking. Recently, we have demonstrated inhibition of breast cancer resistance protein (ABCG2) by olomoucine II and purvalanol A and shown that these compounds are able to synergistically potentiate the antiproliferative effect of mitoxantrone, an ABCG2 substrate. In this follow up study, we investigated whether olomoucine II and purvalanol A are transported by ABCG2 and ABCB1 (P-glycoprotein). Using monolayers of MDCKII cells stably expressing human ABCB1 or ABCG2, we demonstrated that olomoucine II, but not purvalanol A, is a dual substrate of both ABCG2 and ABCB1. We, therefore, assume that pharmacokinetics of olomoucine II will be affected by both ABCB1 and ABCG2 transport proteins, which might potentially result in limited accumulation of the compound in tumor tissues or lead to drug-drug interactions. Pharmacokinetic behavior of purvalanol A, on the other hand, does not seem to be affected by either ABCG2 or ABCB1, theoretically favoring this drug in the potential treatment of efflux transporter-based multidrug resistant tumors. In addition, we observed intensive sulfatation of olomoucine II in MDCKII cell lines with subsequent active efflux of the metabolite out of the cells. Therefore, care should be taken when performing pharmacokinetic studies in MDCKII cells, especially if radiolabeled substrates are used; the generated sulfated conjugate may largely contaminate pharmacokinetic analysis and result in misleading interpretation. With regard to chemical structures of olomoucine II and purvalanol A, our data emphasize that even drugs with remarkable structure similarity may show different pharmacokinetic behavior such as interactions with ABC transporters or biotransformation enzymes.

• MeSH
• ABC transportér z rodiny G, člen 2 MeSH
• ABC transportéry metabolismus   MeSH
• biologický transport MeSH
• buněčné linie MeSH
• chemorezistence účinky léků   MeSH
• nádorové proteiny metabolismus   MeSH
• P-glykoprotein metabolismus   MeSH
• P-glykoproteiny MeSH
• psi MeSH
• puriny farmakokinetika   MeSH
• zvířata MeSH
• Check Tag
• psi MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• 6-((3-chloro)anilino)-2-(isopropyl-2-hydroxyethylamino)-9-isopropylpurine MeSH Prohlížeč
• ABC transportér z rodiny G, člen 2 MeSH
• ABC transportéry MeSH
• ABCB1 protein, human MeSH Prohlížeč
• ABCG2 protein, human MeSH Prohlížeč
• nádorové proteiny MeSH
• olomoucine II MeSH Prohlížeč
• P-glykoprotein MeSH
• P-glykoproteiny MeSH
• puriny MeSH

BACKGROUND: Olomoucine II, the most recent derivative of roscovitine, is an exceptionally potent pharmacological inhibitor of cyclin-dependent kinase activities. Here, we report that olomoucine II is also an effective antiviral agent. METHODS: Antiviral activities of olomoucine II were tested on a range of human viruses in in vitro assays that evaluated viral growth and replication. RESULTS: Olomoucine II inhibited replication of a broad range of wild-type human viruses, including herpes simplex virus, human adenovirus type-4 and human cytomegalovirus. Olomoucine II also inhibited replication of vaccinia virus and herpes simplex virus mutants resistant to conventional acyclovir treatment. This report is the first demonstration of a poxvirus being sensitive to a cyclin-dependent kinase inhibitor. The antiviral effects of olomoucine II could be observed at lower concentrations than with roscovitine, although both were short-term. A remarkable observation was that olomoucine II, when used in combination with the DNA polymerase inhibitor cidofovir, was able to almost completely eliminate the spread of infectious adenovirus type-4 progeny from infected cells. CONCLUSIONS: Our results show that when targeting two complementary antiviral mechanisms, strongly additive effects could be observed.

• MeSH
• antivirové látky farmakologie   MeSH
• cyklin-dependentní kinasy antagonisté a inhibitory   MeSH
• fyziologie virů účinky léků   MeSH
• inhibiční koncentrace 50 MeSH
• inhibitory proteinkinas farmakologie   MeSH
• lidé MeSH
• puriny farmakologie   MeSH
• replikace viru účinky léků   MeSH
• viry enzymologie   růst a vývoj   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• antivirové látky MeSH
• cyklin-dependentní kinasy MeSH
• inhibitory proteinkinas MeSH
• olomoucine II MeSH Prohlížeč
• puriny MeSH