As malaria control programmes concentrate their efforts towards malaria elimination a better understanding of malaria transmission patterns at fine spatial resolution units becomes necessary. Defining spatial units that consider transmission heterogeneity, human movement and migration will help to set up achievable malaria elimination milestones and guide the creation of efficient operational administrative control units. Using a combination of genetic and epidemiological data we defined a malaria transmission unit as the area contributing 95% of malaria cases diagnosed at the catchment facility located in the town of Guapi in the South Pacific Coast of Colombia. We provide data showing that P. falciparum malaria transmission is heterogeneous in time and space and analysed, using topological data analysis, the spatial connectivity, at the micro epidemiological level, between parasite populations circulating within the unit. To illustrate the necessity to evaluate the efficacy of malaria control measures within the transmission unit in order to increase the efficiency of the malaria control effort, we provide information on the size of the asymptomatic reservoir, the nature of parasite genotypes associated with drug resistance as well as the frequency of the Pfhrp2/3 deletion associated with false negatives when using Rapid Diagnostic tests.Sustained global malaria control and elimination initiatives, driven by local and international funding agencies, regional malaria control programmes, and the World Health Organisation (WHO), have led to a dramatic decrease in malaria mortality and case incidence in the last 15 years. Worldwide, there has been a reduction in case incidence of 18% and reduction in mortality of 48%, with significant impact in Africa 1 . Although the 2019 WHO Malaria Report suggests that progress may be slowing, malaria elimination is still an active target for many Colombia, represents relatively high gametocytemia 39,40 . More than 96% of malaria cases diagnosed at the Guapi malaria health facility originated within a 25 km radius of the town of Guapi. We therefore define the Guapi malaria transmission unit as the area where the catchment facility captures 95% of cases ( Fig. S1 4). Scientific RepoRtS |(2020) 10:3756 | https://doi.

Abstract(–)-Epigallocatechin-3-gallate (EGCG), the major active polyphenol extracted from green tea, has been shown to induce apoptosis and inhibit cell proliferation, cell invasion, angiogenesis and metastasis. Herein, we evaluated the in vivo effects of EGCG in acute myeloid leukaemia (AML) using an acute promyelocytic leukaemia (APL) experimental model (PML/RARα). Haematological analysis revealed that EGCG treatment reversed leucocytosis, anaemia and thrombocytopenia, and prolonged survival of PML/RARα mice. Notably, EGCG reduced leukaemia immature cells and promyelocytes in the bone marrow while increasing mature myeloid cells, possibly due to apoptosis increase and cell differentiation. The reduction of promyelocytes and neutrophils/monocytes increase detected in the peripheral blood, in addition to the increased percentage of bone marrow cells with aggregated promyelocytic leukaemia (PML) bodies staining and decreased expression of PML-RAR oncoprotein corroborates our results. In addition, EGCG increased expression of neutrophil differentiation markers such as CD11b, CD14, CD15 and CD66 in NB4 cells; and the combination of all-trans retinoic acid (ATRA) plus EGCG yield higher increase the expression of CD15 marker. These findings could be explained by a decrease of peptidyl-prolyl isomerase NIMA-interacting 1 (PIN1) expression and reactive oxygen species (ROS) increase. EGCG also decreased expression of substrate oncoproteins for PIN1 (including cyclin D1, NF-κB p65, c-MYC, and AKT) and 67 kDa laminin receptor (67LR) in the bone marrow cells. Moreover, EGCG showed inhibition of ROS production in NB4 cells in the presence of N-acetyl-L-cysteine (NAC), as well as a partial blockage of neutrophil differentiation and apoptosis, indicating that EGCG-activities involve/or are in response of oxidative stress. Furthermore, apoptosis of spleen cells was supported by increasing expression of BAD and BAX, parallel to BCL-2 and c-MYC decrease. The reduction of spleen weights of PML/RARα mice, as well as apoptosis induced by EGCG in NB4 cells in a dose-dependent manner confirms this assumption. Our results support further evaluation of EGCG in clinical trials for AML, since EGCG could represent a promising option for AML patient ineligible for current mainstay treatments.

Nuclear factor-erythroid 2 related factor (NRF2) is involved in cell defense and survival against endogenous and exogenous stress. Constitutively active Nrf2 in malignant cells increases the expression of cytoprotective genes and consequently, enhances proliferation via metabolic reprograming and inhibition of apoptosis (Leinonem, Advances in cancer Research, 2014). NRF2 is persistently activated in many human tumors, including acute myelogenous leukemia thus, inhibition of NRF2 activity may be a promising strategy for leukemia therapy. Flavonoids, present in vegetables, fruit and propolis, might exert antitumoral effects through induction of apoptosis and chromatin remodeling (Link, Biochem Pharmacol., 2010). A previous study from our group showed that Quercetin (Qu), a natural polyphenolic flavonoid compound, induced apoptosis, partly due to its DNA demethylating activity, through HDAC inhibition and by the enrichment of H3ac and H4ac in the promoter regions of genes involved in the apoptosis pathway, leading to their transcription activation (Alvarez, Clinical epigenetics 2018). In the present study, we evaluated the effect of Qu as a modulator of NRF2. This study was performed in vivo in human xenograft acute myeloid leukemia (AML) models, and in vitro using leukemia cell lines. Qu treatment (50 µM Qu) for 48h downregulated HDAC4, NRF2 and p-NRF2 at protein levels (p<0.05; p<0.005; p<0.005 respectively). Imaging Flow Cytometry (AMNIS, ImageStream ISX mkIITM) and Confocal Microscopy evidenced a decrease in NRF2 nuclear localization. Furthermore, combined treatment with the proteasome inhibitor MG132 prevented degradation of NRF2, indicating that treatment increased proteasomal degradation. Loss of NRF2 decreases HDAC4, a redox sensitive histone deacetylase, resulting in an increased expression of miR-1 and miR-206 (Singh, J Clin Invest. 2013). Herein, expression profile of 84 miRNAs (Apoptosis miRNA PCR array) were performed in samples from human xenograft model. Treatment up-regulated the expression profile of 5% (n=4) of the 84 miRNAs evaluated, corresponding exclusively to miRNAs that target anti-apoptotic genes and to miRNAs that have been demonstrated to have pro-apoptotic functions. Furthermore, expression levels of miR-1, miR-133a/b, which target anti-apoptotic genes and miR-206, a pro apoptotic miR, were validated in xenograft model samples, resulting in a significant up-regulation of the expression levels in treated animals compared to controls (p<0.05). In addition, lentiviral sh down regulation of NRF2, led to an increased apoptosis, decreased cell survival and an up regulation of miRNA 206 expression in Qu treated cells. In summary, Qu might induce programmed cell death in part, by decreasing NRF2 nuclear localization, by inducing NRF2 proteasomal degradation and down regulation of HDAC4 which led to up-regulation of pro apoptotic miRNAs. Disclosures No relevant conflicts of interest to declare.

Cellular senescence is recognized as a dynamic process in which cells evolve and adapt in a context dependent manner; consequently, senescent cells can exert both beneficial and deleterious effects on their surroundings. Specifically, senescent mesenchymal stromal cells (MSC) in the bone marrow (BM) have been linked to the generation of a supporting microenvironment that enhances malignant cell survival. However, the study of MSC’s senescence role in leukemia development has been straitened not only by the availability of suitable models that faithfully reflect the structural complexity and biological diversity of the events triggered in the BM, but also by the lack of a universal, standardized method to measure senescence. Despite these constraints, two- and three dimensional in vitro models have been continuously improved in terms of cell culture techniques, support materials and analysis methods; in addition, research on animal models tends to focus on the development of techniques that allow tracking leukemic and senescent cells in the living organism, as well as to modify the available mice strains to generate individuals that mimic human BM characteristics. Here, we present the main advances in leukemic niche modeling, discussing advantages and limitations of the different systems, focusing on the contribution of senescent MSC to leukemia progression.

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