Identification of Hub Genes and Pathways Associated with CAR-T Cell-Mediated Neurotoxicity in DLBCL.

BACKGROUND: Severe neurotoxicity after chimeric antigen receptor T cell (CAR-T) therapy can be a crucial lifethreatening event in diffuse large B-cell lymphoma (DLBCL), and management of those toxicities is still a serious clinical challenge. The underlying mechanisms of CAR-T cell-mediated neurotoxicity remain poorly elucidated because very few studies examine the intact tumor microenvironment before CAR-T cell infusion. Herein, we pur-posed to identify differentially expressed genes (DEGs) related to CAR-T cell-mediated neurotoxicity in the DLBCL microenvironment before CAR-T cell infusion and reveal their potential mechanisms. METHODS: The mRNA expression profile data of GSE153438 were obtained from the GEO database. The GSE153438 dataset includes 26 samples with non-severe neurotoxicity (grade 0 - 2) and 10 samples with severe neurotoxicity (grade 3 or higher). Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) patway enrichment assessment was carried out. We screened the hub gene by protein-protein interaction (PPI) network analysis and Cytoscape software. Gene set enrichment analysis (GSEA) was also analyzed with the GSEA software. Moreover, the predictive value of the hub gene for severe neurotoxicity was evaluated via receiver operating characteristic (ROC) curve analysis. RESULTS: We identified a total of 25 up-regulated DEGs and 26 downregulated DEGs associated with CAR-T cell-mediated neurotoxicity in the DLBCL microenvironment before CAR-T cell infusion. Results of GO analysis showed that DEGs were mainly enriched in T cell activation, leukocyte cell-cell adhesion, and positive regulation of cell adhesion. The KEGG analysis revealed that DEGs were significantly enriched in T cell receptor signaling pathway, cell adhesion molecules, and Epstein-Barr virus infection. GSEA revealed that the glycolysis pathway was significantly associated with severe neurotoxicity. The top centrality hub gene GZMB was identified from the PPI network. ROC curve analysis showed that GZMB had a potential predictive value for severe neurotoxicity. CONCLUSIONS: In DLBCL microenvironment before CAR-T cell infusion, we identified T cell activation and glycolysis pathways significantly associated with CAR-T cell-mediated severe neurotoxicity. GZMB might be used as a predictive and therapeutic molecular marker for neurotoxicity. The study suggested that the tumor microenviron-ment before CAR-T cell infusion plays an essential role in the early prediction of neurotoxicity.

Identification of miRNA-mRNA Network Associated with Acute Myeloid Leukemia Survival.

BACKGROUND Acute myeloid leukemia (AML) is a common hematologic malignancy of adults. The pathophysiological mechanism of AML is not well understood. The purpose of this study was to examine the crucial miRNAs and mRNAs associated with AML survival. MATERIAL AND METHODS The full clinical dataset of miRNA and mRNA expression profiling of AML patients was downloaded from The Cancer Genome Atlas database. Univariate Cox regression analysis was performed to obtain those miRNAs and mRNAs associated with AML survival. A miRNA-mRNA interaction network was constructed. The underlying functions of mRNAs were predicted through Kyoto Encyclopedia of Genes and Genomes (KEEG) pathway enrichment. The expression levels of miRNAs and mRNAs were detected by quantitative real-time polymerase chain reaction (qRT-PCR). RESULTS Fourteen miRNAs and 830 mRNAs associated with AML survival were identified. Of the 14 miRNAs, hsa-mir-425, hsa-mir-1201, and hsa-mir-1978 were identified as risk factors and the other 11 miRNAs were identified as protective factors of AML survival. For target-genes of miRNAs, GTSF1, RTN4R, and CD44 were the top risk factor target-genes associated with AML survival. An interaction network was constructed that including 607 miRNA-target gene pairs associated with AML survival. Target-genes associated with AML survival were significantly enriched in several pathways including pancreatic secretion, calcium signaling pathway, natural killer cell mediated cytotoxicity, and Alzheimer's disease. The qRT-PCR results were consistent with our bioinformatics analyses. CONCLUSIONS The miRNA hsa-mir-425 was identified as the top risk factor miRNA of AML survival and CD44 was identified as one of the top three risk factor target-genes associated with AML survival. Both hsa-mir-425 and CD44 may play key roles in progression and development of AML through calcium signaling pathway and natural killer cell mediated cytotoxicity.

Bacterial Folates Provide an Exogenous Signal for C. elegans Germline Stem Cell Proliferation.

Here we describe an in vitro primary culture system for Caenorhabditis elegans germline stem cells. This culture system was used to identify a bacterial folate as a positive regulator of germ cell proliferation. Folates are a family of B-complex vitamins that function in one-carbon metabolism to allow the de novo synthesis of amino acids and nucleosides. We show that germ cell proliferation is stimulated by the folate 10-formyl-tetrahydrofolate-Glun both in vitro and in animals. Other folates that can act as vitamins to rescue folate deficiency lack this germ cell stimulatory activity. The bacterial folate precursor dihydropteroate also promotes germ cell proliferation in vitro and in vivo, despite its inability to promote one-carbon metabolism. The folate receptor homolog FOLR-1 is required for the stimulation of germ cells by 10-formyl-tetrahydrofolate-Glun and dihydropteroate. This work defines a folate and folate-related compound as exogenous signals to modulate germ cell proliferation.

Down-regulation of CD44 contributes to the differentiation of HL-60 cells induced by ATRA or HMBA.

CD44 is highly expressed in human acute myeloid leukemia (AML) cells. Some experiments had shown that it was possible to reverse differentiation blockage in AML cells by CD44 ligation with specific antibodies, indicating that CD44 was closely related to the differentiation of leukemia cells. The differentiation of acute promyelocytic leukemia cell line HL-60 cells could be induced by all trans-retinoic acid (ATRA) and hexamethylene bisacetamide (HMBA), but so far the mechanism was not demonstrated clearly. In the present study, we investigated whether ATRA or HMBA induced the growth arrest of HL-60 cells by down-regulating the expression of CD44. The results indicated that the proliferation of HL-60 cells was obviously inhibited and the differentiation was induced by both ATRA and HMBA. The decreased expression of CD44 and cyclin E mRNA, and the increased expression of p27 and p21 at mRNA levels were observed. Furthermore, there was a negative correlation between the expression of CD44 and p27. It was concluded that ATRA and HMBA played a role in the differentiation induction of HL-60 cells, which was mediated by the down-regulation of CD44, accompanied by down-regulation of cyclin E, and up-regulation of p27 and p21 mRNA.

The molecular mechanism of HDAC inhibitors in anticancer effects.

HDACs and HATs are two kinds of enzymes which catalyse deacetylation and acetylation of histone in eukaryotes, whose dynamic balance has accurate regulation for gene transcription and gene expression of eukaryotes at DNA level. Disbalance of them can bring the disorder of proliferation and differentiation in normal cells, and then lead to the initiation of tumor. Their aberrant functions were directly related to the initiation and progression of various tumors, such as promyelocytic leukemia, Hodgkin lymphoma, colonic cancer and gastral cancer. The inhibitors of HDACs are used for treatment of tumor. They can restrain the activity of HDACs and block the inhibition of gene expression caused by the disorder of deacetylation. Its major biological effects lie in inducing differentiation of tumor cells, arresting cell circle at G0/G1, activating cell apoptosis gene, enhancing the sensitivity of chemical therapy and radioactive therapy. So far HDAC has been an important target enzyme in anticancer drug research.