PRIMA-1 induces apoptosis of leukemic cells via inhibiting Bruton's tyrosine kinase
Öz
Purpose: Bruton's tyrosine kinase (Btk) is known to be critical for B-lymphocyte development, proliferation and differentiation of B-cell lineages, convey signal transduction through B cell receptor (BCR). The present study examined the anti-tumor effects of PRIMA-1 on Btk activity and explored the underlying mechanism, such as apoptosis.
Materials and Methods: Western blot analysis and Quantitative real-time polymerase chain reaction were performed to check the effects of PRIMA-1 on Btk expression level in KBM3 and Namalwa cells. Wild-type Btk and Btk-NLS (nuclear targeted Btk) expression plasmids were transfected in COS-7 cells to establish and characterize the role of Btk in apoptosis using fluorescent microscopy and FACS assay.
Results: İn this study, we observed that exposure of acute myelomonocytic leukemia cells to anti-leukemic drug (PRIMA-1) suppressed Btk expression at mRNA and protein level. Consequently, we also noticed a reduction in the expression of Nrf2 and HO-1 proteins. Remarkably, Btk nuclear localization was increased in response to low PRIMA-1 exposure, while higher concentrations of PRIMA-1 suppressed Btk expression. Furthermore, overexpression of nuclear targeted decreased apoptosis and increased cell viability compared to the wild-type Btk.
Conclusion: Our findings suggest that nuclear Btk reduces the cell apoptosis in response to PRIMA-1 exposure through oxidative response via Nrf2 and HO-1.
Anahtar Kelimeler
Kaynakça
- 1. Smith CI, Islam TC, Mattsson PT, Mohamed AJ, Nore BF, Vihinen M. The Tec family of cytoplasmic tyrosine kinases: mammalian Btk, Bmx, Itk, Tec, Txk and homologs in other species. BioEssays : news and reviews in molecular, cellular and developmental biology. 2001;23:436-46.
- 2. Hussain A, Yu L, Faryal R, Mohammad DK, Mohamed AJ, Smith CI. TEC family kinases in health and disease--loss-of-function of BTK and ITK and the gain-of-function fusions ITK-SYK and BTK-SYK. The FEBS journal. 2011;278:2001-10.
- 3. Conley ME, Dobbs AK, Farmer DM, Kilic S, Paris K, Grigoriadou S et al. Primary B cell immunodeficiencies: comparisons and contrasts. Annu Rev Immunol. 2009;27:199-227.
- 4. Mohamed AJ, Yu L, Backesjo CM, Vargas L, Faryal R, Aints A et al. Bruton's tyrosine kinase (Btk): function, regulation, and transformation with special emphasis on the PH domain. Immunol Rev. 2009;228:58-73.
