ABSTRACT
Aurora kinases and cyclin-dependent kinases, which play critical roles in the cell cycle and are frequently overexpressed in a variety of tumors, have been suggested as attractive targets for cancer therapy. JNJ-7706621, a recently identified dual inhibitor of these kinases, is reported to induce cell cycle arrest, endoreduplication, and apoptosis. In the present study, we further investigated the molecular mechanisms underlying these effects. The inhibitor arrested various cells at G2 phase at low concentration, and at both G1 and G2 phases at high concentration. JNJ-7706621 did not prevent localization of Aurora A to the spindle poles, but did inhibit other centrosomal proteins such as TOG, Nek2, and TACC3 in early mitotic phase. Similarly, the drug did not prevent localization of Aurora B to the kinetochore, but did inhibit other chromosomal passenger proteins such as Survivin and INCENP. In the cells exposed to JNJ-7706621 after nocodazole release, Aurora B, INCENP, and Survivin became relocated to the peripheral region of chromosomes, but Plk1 and Prc1 were localized on microtubules in later mitotic phase. Treatment of nocodazole-synchronized cells with JNJ-7706621 was able to override mitotic arrest by preventing spindle checkpoint signaling, resulting in failure of chromosome alignment and segregation. Injection of the drug significantly inhibited the growth of TC135 Ewing's sarcoma cells transplanted into athymic mice by cell cycle arrest and apoptosis. JNJ-7706621 is a unique inhibitor regulating cell cycle progression at multiple points, suggesting that it could be useful for cell cycle analysis and therapy of various cancers, including Ewing's sarcoma.
Subject(s)
Antineoplastic Agents/pharmacology , Cell Cycle Checkpoints/drug effects , Cyclin-Dependent Kinases/antagonists & inhibitors , Mitosis/drug effects , Neoplasms/drug therapy , Protein Kinase Inhibitors/pharmacology , Protein Serine-Threonine Kinases/antagonists & inhibitors , Triazoles/pharmacology , Animals , Aurora Kinase A , Aurora Kinase B , Aurora Kinases , Bone Neoplasms/drug therapy , Bone Neoplasms/enzymology , Bone Neoplasms/pathology , Cell Proliferation/drug effects , Cyclin-Dependent Kinases/metabolism , Cytokinesis/drug effects , Dose-Response Relationship, Drug , HeLa Cells , Humans , Mice , Mice, Nude , Neoplasms/enzymology , Neoplasms/pathology , Nocodazole/pharmacology , Protein Serine-Threonine Kinases/metabolism , Protein Transport , Sarcoma, Ewing/drug therapy , Sarcoma, Ewing/enzymology , Sarcoma, Ewing/pathology , Spindle Apparatus/drug effects , Spindle Apparatus/enzymology , Time Factors , Tubulin Modulators/pharmacology , Tumor Burden , Xenograft Model Antitumor AssaysABSTRACT
STUDY DESIGN: Report of a rare case of an elderly patient with late onset of Arnold Chiari malformation type I with associated syringomyelia that was successfully treated with foramen magnum decompression. OBJECTIVE: To report this rare case along with a literature review. SETTING: Gifu, Japan. METHODS: A 69-year-old woman with a 4-year history of dull pain in her right arm was referred to the clinic. After physical and radiographical examinations, she was diagnosed with Arnold Chiari malformation type I with associated syringomyelia. A foramen magnum decompression by the removal of the outer layer of the dura mater was performed. RESULTS: At 2 years postoperatively, MRI revealed a decrease in the size of the syringomyelia. Her symptoms had also remarkably improved. CONCLUSIONS: A rare case of symptomatic Arnold Chiari malformation type I with associated syringomyelia in an elderly woman was successfully treated with foramen magnum decompression by the removal of the outer layer of the dura mater.
