Isolation of acute myeloid leukemia blasts from blood using a microfluidic device.

Acute myeloid leukemia (AML) is the most common form of acute leukemia in adults and associated with poor prognosis. Unfortunately, most of the patients that achieve clinical complete remission after the treatment will ultimately relapse due to the persistence of minimal residual disease (MRD), that is not measurable using conventional technologies in the clinic. Microfluidics is a potential tool to improve the diagnosis by providing early detection of MRD. Herein, different designs of microfluidic devices were developed to promote lateral and vertical mixing of cells in microchannels to increase the contact area of the cells of interest with the inner surface of the device. Possible interactions between the cells and the surface were studied using fluid simulations. For the isolation of leukemic blasts, a positive selection strategy was used, targeting the cells of interest using a panel of specific biomarkers expressed in immature and aberrant blasts. Finally, once the optimisation was complete, the best conditions were used to process patient samples for downstream analysis and benchmarking, including phenotypic and genetic characterisation. The potential of these microfluidic devices to isolate and detect AML blasts may be exploited for the monitoring of AML patients at different stages of the disease.

Inflammation and Exosomes in Fabry Disease Pathogenesis.

Fabry Disease (FD) is one of the most prevalent lysosomal storage disorders, resulting from mutations in the GLA gene located on the X chromosome. This genetic mutation triggers glo-botriaosylceramide (Gb-3) buildup within lysosomes, ultimately impairing cellular functions. Given the role of lysosomes in immune cell physiology, FD has been suggested to have a profound impact on immunological responses. During the past years, research has been focusing on this topic, and pooled evidence strengthens the hypothesis that Gb-3 accumulation potentiates the production of pro-inflammatory mediators, revealing the existence of an acute inflammatory process in FD that possibly develops to a chronic state due to stimulus persistency. In parallel, extracellular vesicles (EVs) have gained attention due to their function as intercellular communicators. Considering EVs' capacity to convey cargo from parent to distant cells, they emerge as potential inflammatory intermediaries capable of transporting cytokines and other immunomodulatory molecules. In this review, we revisit the evidence underlying the association between FD and altered immune responses and explore the potential of EVs to function as inflammatory vehicles.

Current and Emerging Techniques for Diagnosis and MRD Detection in AML: A Comprehensive Narrative Review.

Acute myeloid leukemia (AML) comprises a group of hematologic neoplasms characterized by abnormal differentiation and proliferation of myeloid progenitor cells. AML is associated with poor outcome due to the lack of efficient therapies and early diagnostic tools. The current gold standard diagnostic tools are based on bone marrow biopsy. These biopsies, apart from being very invasive, painful, and costly, have low sensitivity. Despite the progress uncovering the molecular pathogenesis of AML, the development of novel detection strategies is still poorly explored. This is particularly important for patients that check the criteria for complete remission after treatment, since they can relapse through the persistence of some leukemic stem cells. This condition, recently named as measurable residual disease (MRD), has severe consequences for disease progression. Hence, an early and accurate diagnosis of MRD would allow an appropriate therapy to be tailored, improving a patient's prognosis. Many novel techniques with high potential in disease prevention and early detection are being explored. Among them, microfluidics has flourished in recent years due to its ability at processing complex samples as well as its demonstrated capacity to isolate rare cells from biological fluids. In parallel, surface-enhanced Raman scattering (SERS) spectroscopy has shown outstanding sensitivity and capability for multiplex quantitative detection of disease biomarkers. Together, these technologies can allow early and cost-effective disease detection as well as contribute to monitoring the efficiency of treatments. In this review, we aim to provide a comprehensive overview of AML disease, the conventional techniques currently used for its diagnosis, classification (recently updated in September 2022), and treatment selection, and we also aim to present how novel technologies can be applied to improve the detection and monitoring of MRD.

Polymorphisms within Autophagy-Related Genes Influence the Risk of Developing Colorectal Cancer: A Meta-Analysis of Four Large Cohorts.

The role of genetic variation in autophagy-related genes in modulating autophagy and cancer is poorly understood. Here, we comprehensively investigated the association of autophagy-related variants with colorectal cancer (CRC) risk and provide new insights about the molecular mechanisms underlying the associations. After meta-analysis of the genome-wide association study (GWAS) data from four independent European cohorts (8006 CRC cases and 7070 controls), two loci, DAPK2 (p = 2.19 × 10-5) and ATG5 (p = 6.28 × 10-4) were associated with the risk of CRC. Mechanistically, the DAPK2rs11631973G allele was associated with IL1 ß levels after the stimulation of peripheral blood mononuclear cells (PBMCs) with Staphylococcus aureus (p = 0.002), CD24 + CD38 + CD27 + IgM + B cell levels in blood (p = 0.0038) and serum levels of en-RAGE (p = 0.0068). ATG5rs546456T allele was associated with TNF α and IL1 ß levels after the stimulation of PBMCs with LPS (p = 0.0088 and p = 0.0076, respectively), CD14+CD16- cell levels in blood (p = 0.0068) and serum levels of CCL19 and cortisol (p = 0.0052 and p = 0.0074, respectively). Interestingly, no association with autophagy flux was observed. These results suggested an effect of the DAPK2 and ATG5 loci in the pathogenesis of CRC, likely through the modulation of host immune responses.

Functional Genetic Variants in ATG10 Are Associated with Acute Myeloid Leukemia.

Acute myeloid leukemia (AML) is the most common acute leukemia, characterized by a heterogeneous genetic landscape contributing, among others, to the occurrence of metabolic reprogramming. Autophagy, a key player on metabolism, plays an essential role in AML. Here, we examined the association of three potentially functional genetic polymorphisms in the ATG10 gene, central for the autophagosome formation. We screened a multicenter cohort involving 309 AML patients and 356 healthy subjects for three ATG10 SNPs: rs1864182T>G, rs1864183C>T and rs3734114T>C. The functional consequences of the ATG10 SNPs in its canonical function were investigated in vitro using peripheral blood mononuclear cells from a cohort of 46 healthy individuals. Logistic regression analysis adjusted for age and gender revealed that patients carrying the ATG10rs1864182G allele showed a significantly decreased risk of developing AML (OR [odds ratio] = 0.58, p = 0.001), whereas patients carrying the homozygous ATG10rs3734114C allele had a significantly increased risk of developing AML (OR = 2.70, p = 0.004). Functional analysis showed that individuals carrying the ATG10rs1864182G allele had decreased autophagy when compared to homozygous major allele carriers. Our results uncover the potential of screening for ATG10 genetic variants in AML prevention strategies, in particular for subjects carrying other AML risk factors such as elderly individuals with clonal hematopoiesis of indeterminate potential.

Unravelling the anticancer potential of functionalized chromeno[2,3-b]pyridines for breast cancer treatment.

A selection of new chromeno[2,3-b]pyridines was prepared from chromenylacrylonitriles and N-substituted piperazines, using a novel and efficient synthetic procedure. The compounds were tested for their anticancer activity using breast cancer cell lines MCF-7, Hs578t and MDA-MB-231 and the non-neoplastic cell line MCF-10A for toxicity evaluation. In general, compounds showed higher activity towards the luminal breast cancer subtype (MCF-7), competitive with the reference compound Doxorubicin. The in vivo toxicity assay using C. elegans demonstrated a safe profile for the most active compounds. Chromene 3f revealed a promising drug profile, inhibiting cell growth and proliferation, inducing cell cycle arrest in G2/M phase, apoptosis and microtubule destabilization. The new compounds presented exciting bioactive features and may be used as lead compounds in cancer related drug discovery.

Elucidating the mechanisms of action of parecoxib in the MG-63 osteosarcoma cell line.

Different types of tumors often present an overexpression of cyclooxygenase-2. The aim of this study was to evaluate the effects of parecoxib (NSAID, cyclooxygenase-2 selective inhibitor) in the behavior of the human osteosarcoma MG-63 cell line, concerning several biological features. Cells were exposed to several concentrations of parecoxib for 48 hours. Cell viability/proliferation, cyclooxygenase-2 expression, morphologic alterations, membrane integrity, cell cycle evaluation, cell death and genotoxicity were evaluated. When compared with untreated cells, parecoxib led to a marked decrease in cell viability/proliferation, in COX-2 expression and changes in cell morphology, in a concentration-dependent manner. Cell recuperation was observed after incubation with drug-free medium. Parecoxib exposure increased lactate dehydrogenase release, an arrest of the cell cycle at S-phase and G2/M-phase, as well as growth of the sub-G0/G1-fraction and increased DNA damage. Parecoxib led to a slight increase of necrosis regulated cell death in treated cells, and an increase of autophagic vacuoles, in a concentration-dependent manner. In this study, parecoxib showed antitumor effects in the MG-63 human osteosarcoma cells. The potential mechanism was inhibiting cell proliferation and promoting necrosis. These results further suggested that parecoxib might be a potential candidate for in-vivo studies.

Targeting Metabolic Reprogramming in Acute Myeloid Leukemia.

The cancer metabolic reprogramming allows the maintenance of tumor proliferation, expansion and survival by altering key bioenergetics, biosynthetic and redox functions to meet the higher demands of tumor cells. In addition, several metabolites are also needed to perform signaling functions that further promote tumor growth and progression. These metabolic alterations have been exploited in different cancers, including acute myeloid leukemia, as novel therapeutic strategies both in preclinical models and clinical trials. Here, we review the complexity of acute myeloid leukemia (AML) metabolism and discuss how therapies targeting different aspects of cellular metabolism have demonstrated efficacy and how they provide a therapeutic window that should be explored to target the metabolic requirements of AML cells.

α-Synuclein toxicity in yeast and human cells is caused by cell cycle re-entry and autophagy degradation of ribonucleotide reductase 1.

α-Synuclein (aSyn) toxicity is associated with cell cycle alterations, activation of DNA damage responses (DDR), and deregulation of autophagy. However, the relationships between these phenomena remain largely unknown. Here, we demonstrate that in a yeast model of aSyn toxicity and aging, aSyn expression induces Ras2-dependent growth signaling, cell cycle re-entry, DDR activation, autophagy, and autophagic degradation of ribonucleotide reductase 1 (Rnr1), a protein required for the activity of ribonucleotide reductase and dNTP synthesis. These events lead to cell death and aging, which are abrogated by deleting RAS2, inhibiting DDR or autophagy, or overexpressing RNR1. aSyn expression in human H4 neuroglioma cells also induces cell cycle re-entry and S-phase arrest, autophagy, and degradation of RRM1, the human homologue of RNR1, and inhibiting autophagic degradation of RRM1 rescues cells from cell death. Our findings represent a model for aSyn toxicity that has important implications for understanding synucleinopathies and other age-related neurodegenerative diseases.

Exploitation of new chalcones and 4H-chromenes as agents for cancer treatment.

Chalcone and chromene derivatives were synthesized in good yield through simple and effective reactions using innocuous solvents such as water and ethanol and high yielding aldol condensations. Generally, the reactions were performed at room temperature, leading to the isolation of highly pure compounds. These compounds were tested on breast cancer cells (MCF-7 and Hs578T) and breast non-neoplastic cells (MCF-10A). After determination of IC50 value, specific assays were performed to analyze the potential of these compounds, and those bearing halogenated substituents presented enhanced activity comparing to methoxyl or methyl groups. More specifically, the bromine atom was often present in the bioactive molecules that proceeded to the final assays and showed to be promising candidates for further studies. The selected chromene acted as a cell migration inhibitory agent and triggered regulated cell death associated with G2/M cell-arrest and microtubule destabilization. For chalcones, the results suggest an anti-proliferative activity. Also, results for combination-therapy potentiated the antitumor effect of doxorubicin and reduced cytotoxicity in MCF-10A cells.

Signalling mechanisms that regulate metabolic profile and autophagy of acute myeloid leukaemia cells.

Acute myeloid leukaemia (AML) comprises a heterogeneous group of hematologic neoplasms characterized by diverse combinations of genetic, phenotypic and clinical features representing a major challenge for the development of targeted therapies. Metabolic reprogramming, mainly driven by deregulation of the nutrient-sensing pathways as AMPK, mTOR and PI3K/AKT, has been associated with cancer cells, including AML cells, survival and proliferation. Nevertheless, the role of these metabolic adaptations on the AML pathogenesis is still controversial. In this work, the metabolic status and the respective metabolic networks operating in different AML cells (NB-4, HL-60 and KG-1) and their impact on autophagy and survival was characterized. Data show that whereas KG-1 cells exhibited preferential mitochondrial oxidative phosphorylation metabolism with constitutive co-activation of AMPK and mTORC1 associated with increased autophagy, NB-4 and HL-60 cells displayed a dependent glycolytic profile mainly associated with AKT/mTORC1 activation and low autophagy flux. Inhibition of AKT is disclosed as a promising therapeutical target in some scenarios while inhibition of AMPK and mTORC1 has no major impact on KG-1 cells' survival. The results highlight an exclusive metabolic profile for each tested AML cells and its impact on determination of the anti-leukaemia efficacy and on personalized combinatory therapy with conventional and targeted agents.

Cell sheet engineering using the stromal vascular fraction of adipose tissue as a vascularization strategy.

Current vascularization strategies for Tissue Engineering constructs, in particular cell sheet-based, are limited by time-consuming and expensive endothelial cell isolation and/or by the complexity of using extrinsic growth factors. Herein, we propose an alternative strategy using angiogenic cell sheets (CS) obtained from the stromal vascular fraction (SVF) of adipose tissue that can be incorporated into more complex constructs. Cells from the SVF were cultured in normoxic and hypoxic conditions for up to 8days in the absence of extrinsic growth factors. Immunocytochemistry against CD31 and CD146 revealed spontaneous organization in capillary-like structures, more complex after hypoxic conditioning. Inhibition of HIF-1α pathway hindered capillary-like structure formation in SVF cells cultured in hypoxia, suggesting a role of HIF-1α. Moreover, hypoxic SVF cells showed a trend for increased secretion of angiogenic factors, which was reflected in increased network formation by endothelial cells cultured on matrigel using that conditioned medium. In vivo implantation of SVF CS in a mouse hind limb ischemia model revealed that hypoxia-conditioned CS led to improved restoration of blood flow. Both in vitro and in vivo data suggest that SVF CS can be used as simple and cost-efficient tools to promote functional vascularization of TE constructs. STATEMENT OF SIGNIFICANCE: Neovascularization after implantation is a major obstacle for producing clinically viable cell sheet-based tissue engineered constructs. Strategies using endothelial cells and extrinsic angiogenic growth factors are expensive and time consuming and may raise concerns of tumorigenicity. In this manuscript, we describe a simplified approach using angiogenic cell sheets fabricated from the stromal vascular fraction of adipose tissue. The strong angiogenic behavior of these cell sheets, achieved without the use of external growth factors, was further stimulated by low oxygen culture. When implanted in an in vivo model of hind limb ischemia, the angiogenic cell sheets contributed to blood flux recovery. These cell sheets can therefore be used as a straightforward tool to increase the neovascularization of cell sheet-based thick constructs.

Proteolytic systems and AMP-activated protein kinase are critical targets of acute myeloid leukemia therapeutic approaches.

The therapeutic strategies against acute myeloid leukemia (AML) have hardly been modified over four decades. Although resulting in a favorable outcome in young patients, older individuals, the most affected population, do not respond adequately to therapy. Intriguingly, the mechanisms responsible for AML cells chemoresistance/susceptibility are still elusive. Mounting evidence has shed light on the relevance of proteolytic systems (autophagy and ubiquitin-proteasome system, UPS), as well as the AMPK pathway, in AML biology and treatment, but their exact role is still controversial. Herein, two AML cell lines (HL-60 and KG-1) were exposed to conventional chemotherapeutic agents (cytarabine and/or doxorubicin) to assess the relevance of autophagy and UPS on AML cells' response to antileukemia drugs. Our results clearly showed that the antileukemia agents target both proteolytic systems and the AMPK pathway. Doxorubicin enhanced UPS activity while drugs' combination blocked autophagy specifically on HL-60 cells. In contrast, KG-1 cells responded in a more subtle manner to the drugs tested consistent with the higher UPS activity of these cells. In addition, the data demonstrates that autophagy may play a protective role depending on AML subtype. Specific modulators of autophagy and UPS are, therefore, promising targets for combining with standard therapeutic interventions in some AML subtypes.

P. brasiliensis virulence is affected by SconC, the negative regulator of inorganic sulfur assimilation.

Conidia/mycelium-to-yeast transition of Paracoccidioidesbrasiliensis is a critical step for the establishment of paracoccidioidomycosis, a systemic mycosis endemic in Latin America. Thus, knowledge of the factors that mediate this transition is of major importance for the design of intervention strategies. So far, the only known pre-requisites for the accomplishment of the morphological transition are the temperature shift to 37 °C and the availability of organic sulfur compounds. In this study, we investigated the auxotrophic nature to organic sulfur of the yeast phase of Paracoccidioides, with special attention to P. brasiliensis species. For this, we addressed the role of SconCp, the negative regulator of the inorganic sulfur assimilation pathway, in the dimorphism and virulence of this pathogen. We show that down-regulation of SCONC allows initial steps of mycelium-to-yeast transition in the absence of organic sulfur compounds, contrarily to the wild-type fungus that cannot undergo mycelium-to-yeast transition under such conditions. However, SCONC down-regulated transformants were unable to sustain yeast growth using inorganic sulfur compounds only. Moreover, pulses with inorganic sulfur in SCONC down-regulated transformants triggered an increase of the inorganic sulfur metabolism, which culminated in a drastic reduction of the ATP and NADPH cellular levels and in higher oxidative stress. Importantly, the down-regulation of SCONC resulted in a decreased virulence of P. brasiliensis, as validated in an in vivo model of infection. Overall, our findings shed light on the inability of P. brasiliensis yeast to rely on inorganic sulfur compounds, correlating its metabolism with cellular energy and redox imbalances. Furthermore, the data herein presented reveal SconCp as a novel virulence determinant of P. brasiliensis.

DNA replication stress-induced loss of reproductive capacity in S. cerevisiae and its inhibition by caloric restriction.

In many organisms, attenuation of growth signaling by caloric restriction or mutational inactivation of growth signaling pathways extends lifespan and protects against cancer and other age-related diseases. The focus of many efforts to understand these effects has been on the induction of oxidative stress defenses that inhibit cellular senescence and cell death. Here we show that in the model organism S. cerevisiae, growth signaling induces entry of cells in stationary phase into S phase in parallel with loss of reproductive capacity, which is enhanced by elevated concentrations of glucose. Overexpression of RNR1 encoding a ribonucleotide reductase subunit required for the synthesis of deoxynucleotide triphosphates and DNA replication suppresses the accelerated loss of reproductive capacity of cells cultured in high glucose. The reduced reproductive capacity of these cells is also suppressed by excess threonine, which buffers dNTP pools when ribonucleotide reductase activity is limiting. Caloric restriction or inactivation of the AKT homolog Sch9p inhibits senescence and death in stationary phase cells caused by the DNA replication inhibitor hydroxyurea or by inactivation of the DNA replication and repair proteins Sgs1p or Rad27p. Inhibition of DNA replication stress represents a novel mechanism by which caloric restriction promotes longevity in S. cerevisiae. A similar mechanism may promote longevity and inhibit cancer and other age-related diseases in humans.

Morphological heterogeneity of Paracoccidioides brasiliensis: relevance of the Rho-like GTPase PbCDC42.

Paracoccidioides brasiliensis budding pattern and polymorphic growth were previously shown to be closely linked to the expression of PbCDC42 and to influence the pathogenesis of the fungus. In this work we conducted a detailed morphogenetic evaluation of the yeast-forms of 11 different clinical and environmental P. brasiliensis isolates comprising four phylogenetic lineages (S1, PS2, PS3 and Pb01-like), as well as a PbCDC42 knock-down strain. High variations in the shape and size of mother and bud cells of each isolate were observed but we did not find a characteristic morphologic profile for any of the phylogenetic groups. In all isolates studied, the bud size and shape were demonstrated to be highly dependent on the mother cell. Importantly, we found strong correlations between PbCDC42 expression and both the shape of mother and bud cells and the size of the buds in all isolates and the knock-down strain. Our results suggested that PbCDC42 expression can explain approximately 80% of mother and bud cell shape and 19% of bud cell size. This data support PbCDC42 expression level as being a relevant predictor of P. brasiliensis morphology. Altogether, these findings quantitatively describe the polymorphic nature of the P. brasiliensis yeast form and provide additional support for the key role of PbCDC42 expression on yeast cell morphology.

The C allele of rs5743836 polymorphism in the human TLR9 promoter links IL-6 and TLR9 up-regulation and confers increased B-cell proliferation.

In humans, allelic variants in Toll-like receptors (TLRs) associate with several pathologies. However, the underlying cellular and molecular mechanisms of this association remain largely unknown. Analysis of the human TLR9 promoter revealed that the C allele of the rs5743836 polymorphism generates several regulatory sites, including an IL-6-responding element. Here, we show that, in mononuclear cells carrying the TC genotype of rs5743836, IL-6 up-regulates TLR9 expression, leading to exacerbated cellular responses to CpG, including IL-6 production and B-cell proliferation. Our study uncovers a role for the rs5743836 polymorphism in B-cell biology with implications on TLR9-mediated diseases and on the therapeutic usage of TLR9 agonists/antagonists.

Isc1p plays a key role in hydrogen peroxide resistance and chronological lifespan through modulation of iron levels and apoptosis.

The inositolphosphosphingolipid phospholipase C (Isc1p) of Saccharomyces cerevisiae belongs to the family of neutral sphingomyelinases that generates the bioactive sphingolipid ceramide. In this work the role of Isc1p in oxidative stress resistance and chronological lifespan was investigated. Loss of Isc1p resulted in a higher sensitivity to hydrogen peroxide that was associated with an increase in oxidative stress markers, namely intracellular oxidation, protein carbonylation, and lipid peroxidation. Microarray analysis showed that Isc1p deficiency up-regulated the iron regulon leading to increased levels of iron, which is known to catalyze the production of the highly reactive hydroxyl radicals via the Fenton reaction. In agreement, iron chelation suppressed hydrogen peroxide sensitivity of isc1Delta mutants. Cells lacking Isc1p also displayed a shortened chronological lifespan associated with oxidative stress markers and aging of parental cells was correlated with a decrease in Isc1p activity. The analysis of DNA fragmentation and caspase-like activity showed that Isc1p deficiency increased apoptotic cell death associated with oxidative stress and aging. Furthermore, deletion of Yca1p metacaspase suppressed the oxidative stress sensitivity and premature aging phenotypes of isc1Delta mutants. These results indicate that Isc1p plays an important role in the regulation of cellular redox homeostasis, through modulation of iron levels, and of apoptosis.

Energy conversion coupled to cyanide-resistant respiration in the yeasts Pichia membranifaciens and Debaryomyces hansenii.

Cyanide-resistant respiration (CRR) is a widespread metabolic pathway among yeasts, that involves a mitochondrial alternative oxidase sensitive to salicylhydroxamic acid (SHAM). The physiological role of this pathway has been obscure. We used the yeasts Debaryomyces hansenii and Pichia membranifaciens to elucidate the involvement of CRR in energy conversion. In both yeasts the adenosine triphosphate (ATP) content was still high in the presence of antimycin A or SHAM, but decreased to low levels when both inhibitors were present simultaneously, indicating that CRR was involved in ATP formation. Also the mitochondrial membrane potential (Delta Psi(m)), monitored by fluorescent dyes, was relatively high in the presence of antimycin A and decreased upon addition of SHAM. In both yeasts the presence of complex I was confirmed by the inhibition of oxygen consumption in isolated mitochondria by rotenone. Comparing in the literature the occurrence of CRR and of complex I among yeasts, we found that CRR and complex I were simultaneously present in 12 out of 13 yeasts, whereas in six out of eight yeasts in which CRR was absent, complex I was also absent. Since three phosphorylating sites are active in the main respiratory chain and only one in CRR, we propose a role for this pathway in the fine adjustment of energy provision to the cell.