Decitabine and guadecitabine are hypomethylating agents (HMAs) that exert inhibitory effects against cancer cells. This includes stimulation of anti-tumor immunity in acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS) patients. Treatment of AML and MDS patients with the HMAs confers upregulation of cancer/testis antigens (CTAs) expression including the highly immunogenic CTA NY-ESO-1. This leads to activation of CD4+ and CD8+ T cells for elimination of cancer cells, and it establishes the feasibility to combine cancer vaccine with HMAs to enhance vaccine immunogenicity. Moreover, decitabine and guadecitabine induce the expression of immune checkpoint molecules in AML cells. In this review, the accumulating knowledge on the immunopotentiating properties of decitabine and guadecitabine in AML and MDS patients are presented and discussed. In summary, combination of decitabine or guadecitabine with NY-ESO-1 vaccine enhances vaccine immunogenicity in AML patients. T cells from AML patients stimulated with dendritic cell (DC)/AML fusion vaccine and guadecitabine display increased capacity to lyse AML cells. Moreover, decitabine enhances NK cell-mediated cytotoxicity or CD123-specific chimeric antigen receptor-engineered T cells antileukemic activities against AML. Furthermore, combination of either HMAs with immune checkpoint blockade (ICB) therapy may circumvent their resistance. Finally, clinical trials of either HMAs combined with cancer vaccines, NK cell infusion or ICB therapy in relapsed/refractory AML and high-risk MDS patients are currently underway, highlighting the promising efficacy of HMAs and immunotherapy synergy against these malignancies.
Introduction: Current prognostic markers have improved survival prediction, however, it has not
advanced treatment strategies. Gene expression profiling may identify biological markers suitable as
therapeutic targets. Leukaemia stem cell is associated with adverse outcome, however, its biological
characteristics are still being investigated. We observed higher in vitro cell viability in acute myeloid
leukaemia (AML) samples with poor prognosis, which may be stem cell related. Objective: The
objective of this study was to profile highly expressed genes in an AML sample of poor prognosis/high
viability and compare with a sample of good prognosis/low viability. Method: Subtractive hybridization
was performed on two AML samples with high blast counts (>80%), a poor prognosis, PP (disease free
survival, DFS12 months) sample. The PP sample had
higher CD34+ counts (73% vs 46%) and higher cell viability than the GP sample. cDNA libraries were
subsequently cloned and sequenced. Results: cDNA subtracted from the PP samples was identified
as genes active during fetal/embryonic development (LCOR, CNOT1, ORMDL1), HOX- related genes
(HOXA3, PBX3, SF3B1), hematopoiesis (SELL, IL-3RA) and aerobic glycolysis/hypoxia (PGK1,
HIGD1A) -associated genes. Majority of GP clones isolated contained genes involved in oxidative
phosphorylation, OXPHOS (COXs, ATPs, MTND4 and MTRNR2), protein synthesis (including
ribosomal proteins, initiating and elongation factors), chromatin remodeling (H2AFZ, PTMA), cell
motility (MALAT1, CALM2, TMSB4X), and mitochondria (HSPA9, MPO) genes. Conclusion: Thus,
the PP sample exhibited stem cell-like features while the GP sample showed cells at a high level of cell
activity. These genes are potential prognostic markers and targets for therapy.
Methods that allow expansion of myeloid dendritic cells (MDCs) from CD34(+) cells are potentially important for boosting anti-leukemic responses after cord blood (CB) hematopoietic stem cell transplantation (HSCT). We showed that the combination of early-acting cytokines FLT3-ligand (FL), stem cell factor (SCF), interleukin (IL)-3, and IL-6 supported the generation of CD11c(+)CD16() CD1a()/c() MDCs from CB CD34(+) cells or CB myeloid precursors. Early-acting cytokine-derived MDCs were maintained within the myeloid CD33(+)CD14()CD15() precursors with a mean of 4 x 10(6) cells generated from 1-4 x 10(4) CB CD34(+) cells or myeloid precursors after 2 weeks. After 8-12 days of culture the MDCs expressed higher levels of HLA-DR antigen but lower levels of CD40 and CD86 antigen, compared to adult blood MDCs. At this stage of differentiation, the early-acting cytokine-derived MDCs had acquired the ability to induce greater allogeneic T cell proliferation than monocytes or granulocytes derived from same culture. Early-acting cytokine-derived MDCs exposed to the cytokine cocktail (CC) comprising IL-1beta, IL-6, tumor necrosis factor (TNF)-alpha, and prostaglandin E (PGE)-2, upregulated the surface co-stimulatory molecules CD40 and CD86 and enhanced allogeneic T cell proliferation, as is characteristic of MDCs maturation. The reliable production of MDCs from CB CD34(+) cells provides a novel way to study their lineage commitment pathway(s) and also a potential means of enriching CB with MDCs to improve prospects for DC immunotherapy following CB HSCT.
Lipopolysacharide (LPS) pre-conditioning (PC), has been shown to exert protective effects against cytotoxic effects. Therefore, we hypothesized, the tolerance produced by LPS PC will be resulted by the alterations and modifications in gene and protein expression. With reference to the results of MTT assays, AO/PI staining, and Annexin V-FITC analyses of LPS concentration (0.7815-50 μg/mL) and time-dependent (12-72 h) experiments, the pre-exposure to 3 μg/mL LPS for 12 h protected the differentiated PC12 cells against 0.75 mg/mL LPS apoptotic concentration. LPS-treated cells secreted more inflammatory cytokines like IL-1α, IL-1β, IL-2, IL-3, IL-4, IL-6, IL-17, IFN-γ, and TNF-α than LPS-PC cells. The production of inflammatory mediators ROS and NO was also higher in the LPS-induced cells compared to LPS-PC cells. Conversely, anti-inflammatory cytokines (like IL-10, IL-13, CNTF, and IL-1Ra) were upregulated in the LPS-PC cells but not in the LPS-induced cells. Meanwhile, the LPS initiated caspase-8 which in turn activates effector caspase 3/7. When the activities of caspases in the LPS-induced cells were inhibited using z-VADfmk and z-DEVDfmk, the expressions of c-MYC and Hsp70 were increased, but p53 was reduced. The potential molecules associated with protective and destructive effect was measured by RT2 Profiler PCR array to elucidate the signaling pathways and suggested inhibition NF-κB/caspase-3 signaling pathway regulates the cytoprotective genes and proto-oncogenes. In conclusion, this study provides a basis for future research to better understand the molecular mechanism underlying LPS pre-conditioning /TLR4 pre-activation and its functional role in offering cytoprotective response in neuronal environment.