R-roscovitine sensitizes anaplastic thyroid carcinoma cells to TRAIL-induced apoptosis via regulation of IKK/NF-kappaB pathway.
Among thyroid carcinomas, highly aggressive undifferentiated or anaplastic carcinomas still await effective therapeutic strategies. R-roscovitine is a novel cyclin-dependent kinase inhibitor in clinical trials as anti-cancer agent. We have investigated the effects of R-roscovitine on proliferation and apoptosis of 4 thyroid cancer cell lines with different degrees of malignancy. R-roscovitine induced cell cycle arrest in G2/M phase in all cells analyzed possibly by inhibiting the CDK1-cyclin B1 complex. However, the compound was unable to induce a significant cell apoptosis. R-roscovitine has been shown to sensitize cancer cells to TRAIL-induced apoptosis. We report that R-roscovitine sensitized thyroid cell lines to TRAIL-induced apoptosis with the highest degree of synergism observed in the most undifferentiated cancer cells. Apoptosis was associated with the activation of caspases. In thyroid cancers, NF-kappaB is constitutively activated contributing to the proliferation of malignant cells. Accordingly, we observed that R-roscovitine inhibited p65 expression and nuclear translocation. Moreover, IKKbeta over-expression inhibited R-roscovitine- and TRAIL-induced apoptosis. The combined treatment also caused down-regulation of anti-apoptotic proteins transcriptionally regulated by NF-kappaB. Finally, R-roscovitine up-regulated expression of DR5 TRAIL receptors. These results demonstrate that undifferentiated thyroid carcinoma cells can be effectively killed by a combination treatment of subtoxic doses of R-roscovitine and TRAIL. R-roscovitine sensitization of TRAIL-induced apoptosis appears to be mediated by the inhibition of the IKK/NF-KB pathway leading to down-regulation of anti-apoptotic genes and up-regulation of TRAIL death receptors. The combination of R-roscovitine and TRAIL may represent a novel approach to the treatment of anaplastic thyroid carcinomas resistant to conventional chemotherapy.
Festa
Michela
M
Department of Pharmaceutical Sciences, University of Salerno, Fisciano, Salerno, Italy.
Petrella
Antonello
A
Alfano
Silvia
S
Parente
Luca
L
D021581:Active Transport, Cell Nucleus / Q000187:drug effects; D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D002277:Carcinoma; D053148:Caspase 3 / Q000378:metabolism; D002455:Cell Division / Q000187:drug effects; D045744:Cell Line, Tumor; D016195:G2 Phase / Q000187:drug effects; D006801:Humans; D051550:I-kappa B Kinase / Q000502:physiology*; D016328:NF-kappa B / Q000502:physiology*; D011687:Purines / Q000494:pharmacology*; D053220:Receptors, TNF-Related Apoptosis-Inducing Ligand / Q000032:analysis; D000077546:Roscovitine; D015398:Signal Transduction / Q000187:drug effects*; D053221:TNF-Related Apoptosis-Inducing Ligand / Q000494:pharmacology*; D013964:Thyroid Neoplasms / Q000188:drug therapy* / Q000473:pathology; D051020:bcl-X Protein / Q000032:analysis
D000970:Antineoplastic Agents; C494811:BCL2L1 protein, human; D016328:NF-kappa B; D011687:Purines; D053220:Receptors, TNF-Related Apoptosis-Inducing Ligand; D053221:TNF-Related Apoptosis-Inducing Ligand; D051020:bcl-X Protein; D000077546:Roscovitine; D051550:I-kappa B Kinase; D053148:Caspase 3