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E3 ubiquitin ligase Cbl-b potentiates the apoptotic action of arsenic trioxide by inhibiting the PI3K/Akt pathway
- Source :
- Brazilian Journal of Medical and Biological Research, Vol 44, Iss 2, Pp 105-111 (2011), Brazilian Journal of Medical and Biological Research, Volume: 44, Issue: 2, Pages: 105-111, Published: FEB 2011, Brazilian Journal of Medical and Biological Research v.44 n.2 2011, Brazilian Journal of Medical and Biological Research, Associação Brasileira de Divulgação Científica (ABDC), instacron:ABDC
- Publication Year :
- 2010
-
Abstract
- Arsenic trioxide (ATO) is a strong inducer of apoptosis in malignant hematological cells. Inducible phosphatidyl inositol 3 kinase (PI3K)-Akt activation promotes resistance to ATO. In the present study, we evaluated whether E3 ubiquitin ligase Cbl-b, a negative regulator of PI3K activation, is involved in the action of ATO. The effect of ATO on cell viability was measured by the Trypan blue exclusion assay or by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Apoptosis was determined by flow cytometry and protein expression was assayed by Western blotting. ATO decreased the viability of HL60 cells and induced cellular apoptosis, which was accompanied by transient activation of Akt. The PI3K/Akt inhibitor, LY294002, significantly increased ATO-induced apoptosis (P < 0.05). In addition, ATO up-regulated the expression of Cbl-b proteins. Furthermore, ATO inhibited cell viability with an IC50 of 18.54 μM at 24 h in rat basophilic leukemia-2H3 cells. ATO induced cellular apoptosis with transient activation of Akt and Cbl-b was also up-regulated. Rat basophilic leukemia-2H3 cells transfected with a dominant negative (DN) Cbl-b mutation showed overexpression of Cbl-b (DN) and enhanced Akt activation. Compared with cells transfected with vector, ATO-induced apoptosis was decreased and G2/M phase cells were increased at the same concentration (P < 0.05). The PI3K/Akt inhibitor, LY294002, re-sensitized Cbl-b (DN) overexpressing cells to ATO and reversed G2/M arrest (P < 0.05). Taken together, these results suggest that Cbl-b potentiates the apoptotic action of ATO by inhibition of the PI3K/Akt pathway.
- Subjects :
- Physiology
Ubiquitin-Protein Ligases
Immunology
Blotting, Western
Biophysics
Apoptosis
HL-60 Cells
Biochemistry
Arsenicals
chemistry.chemical_compound
Arsenic Trioxide
Arsenic trioxide
Animals
Humans
LY294002
Viability assay
Proto-Oncogene Proteins c-cbl
General Pharmacology, Toxicology and Pharmaceutics
Protein kinase B
lcsh:QH301-705.5
PI3K/AKT/mTOR pathway
Phosphoinositide-3 Kinase Inhibitors
lcsh:R5-920
biology
General Neuroscience
Oxides
Cell Biology
General Medicine
Transfection
Flow Cytometry
Molecular biology
Ubiquitin ligase
Rats
Up-Regulation
chemistry
lcsh:Biology (General)
PI3K/Akt pathway
Cbl-b
biology.protein
lcsh:Medicine (General)
Proto-Oncogene Proteins c-akt
Signal Transduction
Subjects
Details
- ISSN :
- 1414431X
- Volume :
- 44
- Issue :
- 2
- Database :
- OpenAIRE
- Journal :
- Brazilian journal of medical and biological research = Revista brasileira de pesquisas medicas e biologicas
- Accession number :
- edsair.doi.dedup.....7f7d1de2850cb4d55202dae97ce291bf