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MLL-rearranged leukemia is an aggressive malignancy associated with poor outcome, which is refractory to conventional treatment. Melatonin has been proven to exert anti-tumor activity, but the effect of melatonin on MLL-r leukemia and the underlying mechanism remain poorly understood. In this study, melatonin inhibited cell proliferation and induced apoptosis by activating the caspase-dependent apoptotic pathway in MLL-r leukemia cells. Mechanistic investigations revealed that melatonin suppressed the expression of hTERT by abrogating the binding activity of RBFOX3 to the hTERT promoter. Melatonin also blocked NF-κB nuclear translocation and suppressed NF-κB binding to the COX-2 promoter, thereby suppressing the expression of COX-2. In addition, clinical samples revealed that melatonin exerts anti-leukemic activity in primary MLL-r leukemia blasts ex vivo. In vivo, the mice treated with melatonin experienced a larger reduction in leukemic burden than the control group in a MLL-r leukemia xenograft mouse model. Collectively, these results suggest that melatonin inhibits MLL-rearranged leukemia through suppressing the RBFOX3/hTERT and NF-κB/COX-2 signaling pathways. Our findings provide new insights into the role of melatonin for MLL-r leukemia treatment. [ABSTRACT FROM AUTHOR]

Acute lymphoblastic leukemia (ALL) is characterized by the accumulation of abnormal lymphoblasts in the bone marrow and blood. Though great progress has been made for improvement in clinical treatment during the past decades, some children with ALL still relapsed. Glucocorticoid (GC) resistance is an important clinical problem for ALL treatment failure. Therefore, further understanding of the mechanism of GC resistance and exploring novel therapeutic strategies are crucial for improving treatment outcome. The reported involvement of microRNAs (miRNAs) in drug resistance implied that deregulated miRNA expression might contribute to GC treatment response of ALL. However, individual miRNAs and their functional mechanisms potentially involved in the GC response are still largely unknown. In the present study, we found that miR-124 was up-regulated in prednisone insensitive human ALL cell line and prednisone-poor response ALL patients. Furthermore, it was found that miR-124 might contribute to GC resistance by promoting proliferation and inhibiting apoptosis of ALL cells. Importantly, we validated that miR-124, targeted and decreased the expression of glucocorticoid receptor (NR3C1), prevented the inhibitory effect of GC in ALL. These findings strongly suggest that miR-124 is critical in poor GC response and may serve as a potential therapeutic target in ALL with poor GC resistance. [ABSTRACT FROM AUTHOR]

• SLE is an autoimmune disease co-mediated by innate and adaptive immunity. The thymus is a central lymphoid organ that can generate functional naive T cells involved in cellular immunity and deplete self-reactive T cells to allow self-tolerance. The changes in the thymus and potential mechanisms underlying the pathogenesis in PIL mice is poorly understood and remain unclear. Thymic T cell differentiation was impaired in the thymus in PIL mice, which might be explained by an inhibition of the DN-to-DP-cell transition and stimulation of DP cell conversion into SP thymocytes. • We further discovered a dramatic and abnormal increase in thymic B cells, and the underlying mechanism of which might be associated with CD19 , Irf8 , Ebf1 , Pax5 , Irf4 , Blk , CXCL13 , CXCR5 , CD79a , CD79b , Lyn , Syk , Btk , and BLNK gene accumulation. Our work represents the first report of the utilization of a transcriptome analysis to study the comprehensive genetic profile and potential mechanism of abnormal thymic B cell activation in PIL mice in detail. The results of our study provide a better understanding of the autoimmune phenomena in the thymus in PIL mice and supplement recent advances in the understanding of PIL mouse pathogenesis. Changes in the thymus and potential mechanisms underlying the pathogenesis in pristane-induced lupus (PIL) mice are poorly understood. This study aimed to systematically and specifically examine changes in the thymus and the potential mechanisms responsible for immunological abnormalities in PIL mice. The results showed that PIL mice exhibit serious thymic hyperplasia, an elevated thymus index, a damaged histopathological structure and increased thymocyte apoptosis. We found that thymic T cell differentiation was impaired as the CD4+ CD8+ double-positive (DP) thymocyte frequency significantly decreased, becoming almost absent at 28 weeks after induction, while CD4 CD8- double-negative (DN) thymocytes and CD4+ CD8- single-positive (CD4+ SP) and CD4 CD8+ single-positive (CD8+ SP) cells were increased. This phenomenon might be explained by an inhibition of the DN-to-DP-cell transition and stimulation of DP cell conversion into CD4+ /CD8+ SP thymocytes. Moreover, we discovered a dramatic and abnormal increase in thymic B cells, that was associated with CD19, Irf8, Ebf1, Pax5, Irf4, Blk, CXCL13, CXCR5, CD79a, CD79b, Lyn, Syk, Btk, and BLNK gene accumulation, which exhibited positive interactions. We further verified that the mRNA expression of these genes was significantly upregulated and consistent with the RNA-seq results. These results suggest a role of these genes in the increase of B cells in the thymus of PIL mice. In summary, our results showed the changes in the thymus in PIL and elucidated the immunologic abnormalities of increased B cells, potentially providing insight into the associated molecular mechanisms and facilitating further research. [ABSTRACT FROM AUTHOR]