[Effect of Dimethyl Fumarate (DMF) on T-cell Acute Lymphoblastic Leukemia].

OBJECTIVE: To explore the effect and possible mechanism of dimethyl fumarate (DMF) on T-cell acute lymphoblastic leukemia (T-ALL), and provide experimental and theoretical basis for the clinical treatment of T-ALL. METHODS: Jurkat cells were treated with different concentrations of DMF for 24 hours, and then the proportion and absolute count of Ki67-positive Jurkat cells were analyzed by flow cytometry. Meanwhile, the protein levels of nuclear factor-erythroid 2-related factor 2 (Nrf2) and E3 ubiquitin ligase HACE1 in Jurkat cells treated with DMF for 24 hours were evaluated by Western blot. Nrf2 proteins were co-immunoprecipitated in Jurkat cells, and then HACE1 protein was assessed by Western blot. Plasmids of Flag-Nrf2 and different gradients of Flag-HACE1 were transfected into HEK293T cells, and the levels of Flag-Nrf2 were detected by Western blot after 48 hours. RESULTS: DMF could significantly inhibit the proportion and absolute count of Ki67-positive Jurkat cells, and DMF inhibited the proliferation of Jurkat cells in a dose-dependent manner (r=0.9595, r=0.9054). DMF could significantly up-regulate the protein levels of Nrf2 and E3 ubiquitin ligase HACE1 in Jurkat cells (P<0.01, P<0.01). HACE1 physically interacted with Nrf2 in Jurkat cells. Overexpression of Flag-HACE1 significantly increased the protein level of Flag-Nrf2 in a dose-dependent manner (r=0.9771). CONCLUSION: DMF inhibits the proliferation of T-cell acute lymphoblastic leukemia cell. The mechanism may be that, DMF significantly up-regulates the protein levels of Nrf2 and E3 ubiquitin ligase HACE1, and HACE1 interacts with Nrf2 and positively regulates Nrf2 protein level.

Angiotensin II enhances the proliferation of Natural Killer/T-cell lymphoma cells via activating PI3K/Akt signaling pathway.

The present study was to determine the roles of Angiotensin (Ang) II in the growth of lymphoma in nude mice and the proliferation and viability of the human Natural Killer/T (NK/T)-cell lymphoma cell line SNK-6, and the activation of downstream signaling pathway. Lymphoma samples and corresponding normal tissues were obtained from lymphoma patients. Proliferation of SNK-6 cells was detected by CCK8 or MTT assay. The levels of Ang II and its receptor Ang II type 1 receptor (AT1R) were higher in lymphoma tissues than those in control tissues. Ang II increased the lymphoma volume and size in nude mice, the proliferation and viability and the proliferating cell nuclear antigen (PCNA) and Ki67 levels of SNK-6 cells. Losartan, an antagonist of AT1R, reduced lymphoma volume and size in nude mice, and the proliferation and viability and the PCNA and Ki67 levels of SNK-6 cells. The levels of phosphorylated phosphatidylinositol 3-kinase (p-PI3K) and phosphorylated protein kinase B (p-Akt) were increased by Ang II and then reduced by losartan in SNK-6 cells. The proliferation and viability of SNK-6 cells were increased by Ang II, but these increases were inhibited by PI3K inhibitor wortmannin and Akt inhibitor MK2206. The increases of PCNA and Ki67 induced by Ang II were inhibited by wortmannin or MK2206 in SNK-6 cells. These results indicate that Ang II/AT1R is activated in lymphoma, and Ang II promotes the progression of lymphoma in nude mice and the proliferation and viability of SNK-6 cells via activating PI3K/Akt signaling pathway.

[Research progress in heterogeneity of human CD4(+)FOXP3(+)T cells].

It is now established that CD4(+)CD25(+)regulatory T (Treg) cells expressing transcription factor FOXP3, a regulatory subpopulation of T cells, is indispensable for the maintenance of immunological self-tolerance and immune homeostasis. FOXP3 expression in Treg cells is specific and it is the key control factor for the development, activation and function of Treg cells. At present, CD4(+)FOXP3(+)T lymphocytes are often used to define Treg cells for scientific research. But recent studies show that human CD4(+)FOXP3(+)T cells are phenotypically and functionally heterogeneous, including suppressive and non suppressive T cells. The different functions of these cell subsets can be distinguished by phenotypic differences. This review discusses the recent research progress about phenotypic characteristics and functional heterogeneity of CD4(+)FOXP3(+)T cell subsets.