Abstract
BackgroundAurora kinase ensures accurate chromosome segregation during cell cycle, maintaining genetic integrity in cell division. VX-680, a small-molecule Aurora kinase inhibitor, interferes with mitotic entry and formation of bipolar spindles. Here, we evaluated VX-680 as a potential agent for treatment of all-trans retinoid acid (ATRA)-resistant acute promyelocytic leukemia (APL) in vitro.MethodsCD11b expression was utilized to assess cell differentiation by flow cytometry. Immunofluorescence staining was conducted to analyze formation of cell monopolar spindle. Cell proliferation was evaluated by MTT assay. Sub-G1 population and Annexin V/PI staining were used to measure cell apoptosis. Hoechst 33342 staining was applied for identifying morphological changes in nucleus of apoptotic cell. Aurora-A (Aur-A) activation and the signaling pathways involved in apoptosis were detected by Western blot. JC-1 probe was employed to measure mitochondrial depolarization.ResultsVX-680 inhibited Aur-A by reducing autophosphorylation at the activation site, Thr288, accompanied by producing monopolar mitotic spindles in APL cell line NB4-R2 that was resistant to ATRA. In addition, we found that VX-680 inhibited cell proliferation as assessed by MTT assay. Flow cytometry showed that VX-680 led to apoptotic cell death in both dose- and time-dependent manners by either Sub-G1 or Annexin V/PI analysis. Hoechst 33342 staining represented typical apoptotic cells with nuclear fragmentation in VX-680 treated cells. Importantly, VX-680 inhibition of Aurora kinase suppressed Akt-1 activation and induced mitochondrial depolarization, which eventually resulted in apoptosis by activation of caspase pathway, as indicated by increasing proteolytic cleavage of procaspase-3 and poly ADP ribose polymerase (PARP) in NB4-R2 cells.ConclusionsOur study suggested potential clinical use of mitotic Aurora kinase inhibitor in targeting ATRA-resistant leukemic cells.
Highlights
Aurora kinase ensures accurate chromosome segregation during cell cycle, maintaining genetic integrity in cell division
We showed that Aurora kinase small-molecule inhibitor VX-680 led to mitotic defects in spindle and decreased expression of phosphorylated Aur-A at the activation site, Thr288 in acute promyelocytic leukemia (APL) cell line NB4-R2 that was resistant to all-trans retinoid acid (ATRA)
Aurora kinase small-molecule inhibitor VX-680 significantly suppresses the proliferation in a number of leukemic cell types In order to demonstrate the specificity of Aurora inhibitory VX-680 on leukemia, OCI-AML3, NB4, HL-60 and ML-1 cells were treated with different doses of VX-680
Summary
Aurora kinase ensures accurate chromosome segregation during cell cycle, maintaining genetic integrity in cell division. Acute promyelocytic leukemia (APL), is characterized by t (15; 17) chromosomal translocation resulting in a fusion transcript of promyelocytic leukemia-retinoid acid receptor a (PML/RARa). PML/RARa represents a most curable subgroup of leukemia with the Serine/threonine kinase Aurora family, including Aurora (Aur)-A, -B and -C, are playing important roles in chromosome segregation during cell cycle and genetic integrity in cell division [5,6]. Our previous study showed Aur-A was of importance for mitotic entry and formation of bipolar spindles [7]. Study showed that Aur-A kinase was highly expressed in acute myeloid leukemia (AML) patients and suppression of Aur-A induced AML cells apoptosis [16]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
