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Chromodomain helicase DNA binding protein 5 (CHD5) was previously proposed to function as a potent tumor suppressor by acting as a master regulator of a tumor-suppressive network. CHD5 is down-regulated in several cancers, including leukemia and is responsible for tumor generation and progression. However, the mechanism of CHD5 down-regulation in leukemia is largely unknown. In this study, quantitative reverse-transcriptase polymerase chain reaction and western blotting analyses revealed that CHD5 was down-regulated in human leukemia cell lines and samples. Luciferase reporter assays showed that most of the baseline regulatory activity was localized from 500 to 200 bp upstream of the transcription start site. Bisulfite DNA sequencing of the identified regulatory element revealed that the CHD5 promoter was hypermethylated in human leukemia cells and samples. Thus, CHD5 expression was inversely correlated with promoter DNA methylation in these samples. Treatment with DNA methyltransferase inhibitor 5-aza-2′-deoxycytidine (DAC) activates CHD5 expression in human leukemia cell lines. In vitro luciferase reporter assays demonstrated that methylation of the CHD5 promoter repressed its promoter activity. Furthermore, a chromatin immunoprecipitation assay combined with qualitative PCR identified activating protein 2 (AP2) as a potential transcription factor involved in CHD5 expression and indicated that treatment with DAC increases the recruitment of AP2 to the CHD5 promoter. In vitro transcription-factor activity studies showed that AP2 over-expression was able to activate CHD5 promoter activity. Our findings indicate that repression of CHD5 gene expression in human leukemia is mediated in part by DNA methylation of its promoter. [ABSTRACT FROM AUTHOR]

Antigen-specific stem-like memory CD8 + T cells (Tscm) have a series of stem cell characteristics, including long-term survival, self-renewal, anti-apoptosis and persistent differentiation into cytotoxic T cells. The effective induction of tumor-specific CD8 + Tscm could persistently eradicate tumor in pro-tumor hostile microenvironment. This study was to investigate the role of CD40 in HPV16-specific CD8 + Tscm induction and its anti-tumor function. We found that CD40 activation accelerated vaccine-induced HPV16 E7-specific CD8 + Tscm formation. Comparing to other HPV-specific CD8 + T cells, CD8 + Tscm were found to be stronger and long-term anti-tumor function, in vivo and in vitro , even in the adoptive cellular transferring model. Furthermore, high frequencies of Tscm might prevent the HPV infection to move on to the development of cancer. And the CD40 effect on Tscm involved Wnt/β-catenin activation. Our study suggest that CD40 activation supports the generation of tumor-specific CD8 + Tscm, thus providing new insight into cancer immunotherapy., (Copyright © 2020 Zhang, Wang, Ding, Yang, Wang, Huang, Zhu, Mellor, Hou, Zhou, Yan, Wang and Wu.)

Objective: To explore the role of aquaporin-1 (AQP1) gene in erythroid differentiation of erythroleukemia K562 cells induced by retinoic acid (RA)., Methods: K562 cells were cultured in the presence of 1 µmol/L RA for varying lengths of time, and γ-globin mRNA expression and hemoglobin content in the cells were detected by real-time PCR (RT-PCR) and ultraviolet spectrophotometry, respectively, to evaluate the erythroid differentiation of K562 cells. RT-PCR and Western blotting were used to examine AQP1 expression in the cells following RA treatment. A retroviral expression vector of AQP1 small interfering RNA (pSUPER-retro-puro-shAQP1) was constructed and transfected into K562 cells to establish a K562 cell line with stable AQP1 down-regulation (K562-shAQP1), in which the changes in γ-globin and hemoglobin expressions after RA treatment were detected., Results: RA treatment significantly increased γ-globin and hemoglobin expressions in K562 cells (P<0.01), causing also significantly enhanced AQP1 mRNA and protein expressions over time (P<0.01). Transfection with the recombinant plasmids pSuper-retro-puro-shAQP1 resulted in stable AQP1 suppression in K562 cells (P<0.01), which showed markedly reduced γ-globin and hemoglobin expressions after RA induction as compared to the control K562 cells (P<0.01)., Conclusion: K562 cells show a significant increase of AQP1 expression after RA-induced erythroid differentiation, and suppression of AQP1 expression can partially block the effect of RA, suggesting the important role of AQP1 in RA-induced erythroid differentiation of K562 cells.