WT1 influences apoptosis and proliferation of immature mice granular cells through regulation of the wnt/beta-catenin signal pathway
CELLULAR AND MOLECULAR BIOLOGY
Authors: Wang, Juan; Qiu, Jianping; Bo, Le; Wu, Zhinan; Zhou, Anwen; Xu, Wendan; Mao, Caiping
Abstract
It was to study the influence of Wilms tumor suppressor gene (WT1) on ovarian granular cells (GCs) in mice, and the molecular mechanism involved. LV-WT1 short hairpin ribonucleic acid (shRNA) vector was used to downregulate WT1 expression in granular cells (GCs). The effects of WTI on proliferation and apoptosis of GCs were investigated. Western blot and qRT-PCR were used to assay the mRNA and protein expressions of Bax/bcl-2 in GCs transfected with LV-WT1-RNAi. The expression levels of SUZ12, Wnt5a, Wnt11, Wnt4, Wnt3a, Wnt2 mRNA in GCs were also determined. LV-WT1-RNAi significantly reduced WT1 expression, increased apoptosis and inhibited proliferation of GCs. The inhibition of WT1 had no significant effect on the expression of bcl-2 in GCs. The expressions of Wnt2, Wnt4 and Wnt5a were augmented in WT1-knockdown GCs, relative to non-transfected cells. WT1 activation is necessary for maintaining early survival of GCs in follicles via activation of the Wnt/beta-catenin signal pathway.
The roles of epigenetic modifications of proapoptotic BID and BIM genes in imatinib-resistant chronic myeloid leukemia cells
HEMATOLOGY
Authors: Bozkurt, Sureyya; Ozkan, Tulin; Ozmen, Fusun; Baran, Yusuf; Sunguroglu, Asuman; Kansu, Emin
Abstract
In chronic myeloid leukemia (CML), epigenetic modifications such as promoter hypermethylation and inactive histone modification are known mechanisms of drug resistance. In our study, we investigated the roles of promoter hypermethylation of BIM and BID genes and H3K27me3 histone modification on imatinib resistance. We detected higher expression levels of BIM and BID genes and lower expression levels of EZH2, EED2, SIRT1, and SUZ12 genes in imatinib-resistant K562/IMA-3 cells compared to imatinib-non-resistant K562 cells. While we determined the EZH2 and DNMT enzymes as bounded to the promoter of the BIM gene, we did not detect hypermethylation of this promoter. We also found the H3K27me3 histone modification promoter of BIM and BID genes in both cell lines. In conclusion, our results support the notion that DNA promoter methylation may be formed independently from EZH2-H3K27me3 and pro-apoptotic BIM and BID genes are not methyllated in the imatinib resistance of CML cells.