miR-133a and miR-135a Regulate All-Trans Retinoic Acid-Mediated Differentiation in Pediatric Acute Myeloid Leukemia by Inhibiting CDX2 Translation and Serve as Prognostic Biomarkers.

Background: Acute myeloid leukemia (AML) is a type of blood cancer characterized by excessive growth of immature myeloid cells. Unfortunately, the prognosis of pediatric AML remains unfavorable. It is imperative to further our understanding of the mechanisms underlying leukemogenesis and explore innovative therapeutic approaches to enhance overall disease outcomes for patients with this condition. Methods: Quantitative reverse-transcription PCR was used to quantify the expression levels of microRNA (miR)-133a and miR-135a in 68 samples from 59 pediatric patients with AML. Dual-luciferase reporter transfection assay, Cell Counting Kit-8 assay, and western blot analysis were used to investigate the functions of miR-133a and miR-135a. Results: Our study found that all-trans-retinoic acid (ATRA) promoted the expression of miR-133a and miR-135a in AML cells, inhibited caudal type homeobox 2 (CDX2) expression, and subsequently inhibited the proliferation of AML cells. Additionally, miR-133a and miR-135a were highly expressed in patients with complete remission and those with better survival. Conclusions: miR-133a and miR-135a may play an antioncogenic role in pediatric AML through the ATRA-miRNA133a/135a-CDX2 pathway. They hold promise as potentially favorable prognostic indicators and novel therapeutic targets for pediatric AML.

The Potential Transcriptomic and Metabolomic Mechanisms of ATO and ATRA in Treatment of FLT3-ITD Acute Myeloid Leukemia.

BACKGROUND: Acute myeloid leukemia (AML) with Fms-like tyrosine kinase 3 gene internal tandem duplication (FLT3-ITD) mutations has a poor prognosis. The combination of arsenic trioxide (ATO) and all-trans retinoic acid (ATRA) has a synergistic killing effect on leukemia cells with FLT3-ITD mutation. However, the mechanism, especially the changes of gene expression and metabolic activity remain unclear. Here we explore the transcriptome and metabolomics changes of FLT3-ITD AML cells treated with ATO/ATRA. METHODS: RNA-seq was used to identify differential expressed genes (DEGs), and ultra-high performance liquid chromatography-quadrupole electrostatic field orbital trap mass spectrometry (UHPLC-QE-MS) nontargeted metabolomics method was used to screen out the differential metabolites in FLT3-ITD mutant cell lines treated with ATRA and ATO. KEGG pathway database was utilized for pathway exploration and Seahorse XF24 was used to detect extracellular acidification rate (ECAR). Metabolic polymerase chain reaction (PCR) array and real-time quantitative PCR (RT-qPCR) were used to detect mRNA levels of key metabolic genes of glycolysis and fatty acid after drug treatment. RESULTS: A total of 3873 DEGs were identified and enriched in 281 Gene Ontology (GO) terms, among which 210 were related to biological processes, 43 were related to cellular components, and 28 were related to molecular functions. Besides, 1794 and 927 differential metabolites were screened in positive and negative ion mode separately, and 59 different metabolic pathways were involved, including alanine-aspartate-glutamate metabolic pathway, arginine, and proline metabolic pathway, glycerophospholipid metabolic pathways, etc. According to KEGG Pathway analysis of transcriptome combined with metabolome, glycolysis/gluconeogenesis pathway and fatty acid metabolism pathway were significantly founded enriched. ATRA + ATO may inhibit the glycolysis of FLT3-ITD AML cells by inhibiting FLT3 and its downstream AKT/HK2-VDAC1 signaling pathway. CONCLUSIONS: The gene transcription profile and metabolites of FLT3-ITD mutant cells changes significantly after treatment, which might be related to the anti-FLT3-ITD AML effect. The screened DEGs, differential metabolites pathway are helpful in studying the mechanism of anti-leukemia effects and drug targets.

Functional Characteristics and Application of Mesenchymal Stem Cells in Systemic Lupus Erythematosus.

Systemic lupus erythematosus (SLE) is a rare, heterogeneous autoimmune and autoinflammatory disease that affects both sexes and all races, although this disease exhibits its highest incidence/prevalence among the black population and shows a predilection for women of reproductive age. Although SLE has no cure, treatment can help decrease its signs and symptoms. Thus, we should focus primarily on personalized treatment. Mesenchymal stem/stromal cells (MSCs), which are multipotent cells capable of differentiating into osteoblasts, chondrocytes, adipocytes, and myoblasts, among other cell types, are potential candidates for use in a promising strategy to treat severe and refractory SLE. MSCs have an immunomodulatory function that can suppress the proliferation and activities of many immune cells, such as T lymphocytes, B lymphocytes, natural killer cells, macrophages and dendritic cells. Substantial progress has recently been made in MSC therapy, and experimental and clinical data suggest that such a therapy is a promising strategy for the treatment of severe and refractory SLE. In this review, we highlight the effects of MSCs on different immune cell types, describe the mechanisms underlying MSC-mediated immunoregulation, and discuss the treatment of SLE with MSCs from different sources in various animal models and clinical applications.

Abnormal thymic B cell activation and impaired T cell differentiation in pristane-induced lupus mice.

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.

Up-regulated miR-155 is associated with poor prognosis in childhood acute lymphoblastic leukemia and promotes cell proliferation targeting ZNF238.

OBJECTIVES: Acute lymphoblastic leukemia (ALL) is one of the most common malignancies in children. Our aim was to identify a novel miRNA that can predict prognosis of childhood ALL patients and explore its potential mechanism. METHODS: The miRNA expression profiles of childhood ALL were analyzed using GEO database and HiSeq instruments. The expression of miR-155 was examined by RT-PCR in 42 ALL patients. To investigate the role of miR-155 in ALL, four ALL cell lines (CEM-C1, Jurkat, MOLT-3 and MOLT-4) were transfected with miR-155 mimics, miR-155 inhibitors or corresponding controls. Dual-luciferase reporter system was applied to confirm the miR-155 target ZNF238. Moreover, proliferation and apoptosis were evaluated by MTT and flow cytometry. RESULTS: Dataset GSE56489 and GSE23024 demonstrated that miR-155 was up-regulated and ZNF238 was down-regulated at diagnosis status of ALL. High miR-155 expression was associated with poor outcome. Overexpressed miR-155 promoted ALL cell proliferation and inhibited apoptosis. Dual-luciferase reporter result showed that miR-155 directly regulated ZNF238. Silencing ZNF238 promoted cell proliferation in ALL cells. DISCUSSION: Our research indicating that miR-155 might possess potential value as a biomarker for predicting the prognosis of individuals. However, the role of ZNF238 in childhood ALL remain unknown. In the present study, we found the possible role of ZNF238 as a new tumor suppressor in ALL, which might be necessary for the antiproliferative functions of normal cells to counteract ALL formation. CONCLUSION: Our results propose that miR-155 is in association with poor prognosis of childhood ALL. Furthermore, miR-155 could promote cell proliferation targeting ZNF238.

Arsenic trioxide and all-trans retinoic acid suppress the expression of FLT3-ITD.

The prognosis of patients with acute myeloid leukemia (AML) caused by the FLT3-ITD mutation is poor. Arsenic trioxide (ATO) and all-trans retinoic acid (ATRA) can down-regulate FLT3-ITD level and selectively kill leukemia cells carrying the FLT3-ITD mutation. However, the mechanisms of action of these two compounds are unknown. Here, we found that ATO could bind FLT3-ITD at Lys91 and Asp225, whereas ATRA could bind FLT3-ITD at Lys5 and Gln6. Both compounds could not bind wild-type FLT3. Further studies revealed that ATO/ATRA may suppress the Expression of FLT3-ITD by promoting the UBE2L6-mediated ubiquitination pathway and decreasing the expression of C-MYC. However, further studies are needed to define the mechanisms of these compounds on AML. Our research provides an experimental basis for the use of ATO/ATRA in FLT3-ITD AML in clinical practice.

Arsenic trioxide induces autophagic degradation of the FLT3-ITD mutated protein in FLT3-ITD acute myeloid leukemia cells.

The prognosis of acute myeloid leukemia (AML) with FMS-like tyrosine kinase 3 internal tandem duplication (FLT3-ITD) mutations is poor. Some studies, including our previous study, have indicated that arsenic trioxide (ATO) exhibited significant anti-carcinogenic activity in FLT3-ITD AML cells and explored the possibility of targeting the FLT3-ITD protein for degradation as a therapy. Autophagy is a critical mechanism of the anti-leukemic effects of ATO. In this study, we explored the therapeutic efficacy of ATO treatment in a mouse model bearing FLT3-ITD AML and found that ATO significantly reduced the leukemic burden in bone marrow and spleen. We also found that autophagy was responsible for, at least in part, the degradation of the FLT3-ITD protein by ATO. After ATO treatment, MV4-11 cells showed complete autophagic flux. The autophagy inhibitor bafilomycin A or down-regulation of the key autophagy genes Atg5 and Atg7 reversed the FLT3 degradation induced by ATO. We also found that p62/SQSTM1 delivered FLT3-ITD proteins to the lysosome, where they were subsequently degraded. These results indicate that ATO can induce autophagic degradation of the FLT3-ITD mutated protein in FLT3-ITD AML.

Melatonin inhibits MLL-rearranged leukemia via RBFOX3/hTERT and NF-κB/COX-2 signaling pathways.

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.