The Downregulation of Both Giant HERCs, HERC1 and HERC2, Is an Unambiguous Feature of Chronic Myeloid Leukemia, and HERC1 Levels Are Associated with Leukemic Cell Differentiation

Large HERC E3 ubiquitin ligase family members, HERC1 and HERC2, are staggeringly complex proteins that can intervene in a wide range of biological processes, such as cell proliferation, DNA repair, neurodevelopment, and inflammation. Therefore, mutations or dysregulation of large HERCs is associated with neurological disorders, DNA repair defects, and cancer. Though their role in solid tumors started to be investigated some years ago, our knowledge about HERCs in non-solid neoplasm is greatly lagging behind. Chronic Myeloid Leukemia (CML) is a model onco-hematological disorder because of its unique and unambiguous relation between genotype and phenotype due to a single genetic alteration. In the present study, we ascertained that the presence of the BCR-ABL fusion gene was inversely associated with the expression of the HERC1 and HERC2 genes. Upon the achievement of remission, both HERC1 and HERC2 mRNAs raised again to levels comparable to those of the healthy donors. Additionally, our survey unveiled that their gene expression is sensitive to different Tyrosine Kinases Inhibitors (TKIs) in a time-dependent fashion. Interestingly, for the first time, we also observed a differential HERC1 expression when the leukemic cell lines were induced to differentiate towards different lineages revealing that HERC1 protein expression is associated with the differentiation process in a lineage-specific manner. Taken together, our findings suggest that HERC1 might act as a novel potential player in blood cell differentiation. Overall, we believe that our results are beneficial to initiate exploring the role/s of large HERCs in non-solid neoplasms.

Circulating Extracellular Vesicles from Acute Myeloid Leukemia Patients Drive Distinct Metabolic Profile of Leukemic Cells and Reveal Crucial Lipidomic Biomarkers

Background. Extracellular vesicles (EVs) are submicron vesicles released from various cell types including blood cells with pleiotropic effects on cell signalling and metabolism. EV cargos are enriched in nucleic acids, proteins, and lipids that can be delivered to target cells to influence surrounding microenvironment. Thus, EVs represent a powerful tool for liquid biopsy in hematological malignancies including acute myeloid leukemia (AML). AML is an aggressive disease with high relapse rate and less invasive tools are urgently needed to investigate disease (metabolic) dynamics. Accumulating evidence has reported a key role for EVs in shaping the AML bone marrow niche. However, at present, the metabolic function and the lipidomic signature driven by circulating EVs have yet to fully emerge. Methods. Peripheral blood (PB) and bone marrow (BM) were collected from AML patients at diagnosis (n=40) and PB from age/sex-matched healthy donors (HD, n=20). EVs were purified from platelet-poor plasma by size exclusion chromatography and quantified using the NanoSight technology. Immunomagnetically isolated CD34+ cells from umbilical cord blood (CB) or AML patients were characterized by analyzing the hematopoietic stem/progenitor cell (HSPC)-specific cluster of differentiation marker expression, redox metabolic profiling (using CellROX, glutathione detection reagent and MitoTracker) after 24 hours co-culture with EVs. Quantitative lipidomic profiling of circulating EVs was performed by Liquid Chromatography coupled with High-Resolution Mass Spectrometry (LC/HRMS). Seahorse extracellular flux analyses were performed in leukemia cell lines (including KG-1, KASUMI-1, MOLM-13, THP-1 and OCI-AML3). To functionally define the metabolic reprogramming of leukemic cellular components within their microenvironment, leukemic stem cell subsets were assessed by flow cytometry-based SCENITH (Single Cell ENergetic metabolism by profilIng Translation inHibition) method in both whole blood and BM samples (n=4). Results. In our work, plasma-derived EVs from AML patients showed a significant increase in the size and protein amounts compared to HD counterparts. To explore the metabolic perturbation triggered by EVs, we developed a co-culture system with circulating EVs from either HD or AML patients with CB or AML CD34+. We found a reduction in the frequency of AML CD34+ with high ROS levels in the presence of AML EVs without affecting the ROS levels in normal CB CD34+. In parallel, AML EVs increased the frequency of AML CD34+ with both high mitochondrial activity and glutathione, a key antioxidant molecule involved in many metabolic pathways. Similar metabolic profiles were also confirmed in human leukemic cell lines tested. Specifically, Seahorse flux analysis revealed that EVs induced a cell energy phenotype consistent with quiescent and chemoresistant state in human leukemic cell lines, showing a more glycolytic state in MOLM-13. Interestingly, both CD34+ and CD34+/CD38- leukemic fractions from whole blood and BM of the same AML patients were analyzed by SCENITH after co-cultures with HD/AML EVs. Remarkably, PB CD34+/CD38- leukemic fractions were more dependent on mitochondrial activity in the presence of AML EVs, suggesting a metabolic shift triggered by leukemic EV that apparently occur in the leukemic fractions out of the BM niche. In addition, to give insights into lipidomic signatures of EVs as disease biomarkers, we detected a total of 25 (out of 200) independent lipid species significantly different between AML-derived EVs and HD (n=20, respectively). We reported the abundance of both glycerolipid and fatty acids species in AML EVs. Also, through a multivariate statistical analysis of EV lipidomic profile, we revealed that AML EVs were depleted in sphingomyelin classes, a class of lipids that are interconnected to HSC metabolism. Finally, according to the 2017 ELN risk stratification system, we observed the depletion in important modulators of EV release and formation as ether-linked phosphatidylethanolamine and phosphatidylethanolamine species in adverse-risk AML patients. Conclusion. Overall, our study provides the basis for further investigations on the metabolic alterations trigger by EVs within the BM microenvironment and suggests prognostic biomarkers for leukemic patients that might reveal novel metabolic vulnerabilities in AML scenario. Disclosures Cavo: Sanofi: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; AbbVie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Novartis: Honoraria; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: TRAVEL, ACCOMMODATIONS, EXPENSES, Speakers Bureau; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel Accommodations, Speakers Bureau; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Adaptive Biotechnologies: Consultancy, Honoraria; GlaxoSmithKline: Consultancy, Honoraria; Bristol-Myers Squib: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Curti: Jazz Pharma: Membership on an entity's Board of Directors or advisory committees; Pfizer: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees; Abbvie: Membership on an entity's Board of Directors or advisory committees.

Punicalagin, a pomegranate compound, induces apoptosis and autophagy in acute leukemia

Background Punicalagin is the major phenolic compound found in pomegranate peels. It has several reported medical benefits, including antioxidant, anti-inflammatory, and anticancer properties. The present study investigated the anti-leukemic effects and the molecular mechanism of punicalagin on NB4 and MOLT-4 leukemic cell lines. Methods Leukemic cells were treated with punicalagin and cell viability was determined using MTS assay. Apoptosis and autophagy were analyzed by flow cytometry using Annexin V-FITC/PI and anti-LC3/FITC antibodies staining, respectively. Apoptotic and autophagic mRNA expression were determined using reverse transcription-quantitative PCR. STITCH bioinformatics tools were used to predict the interaction between punicalagin and its proposed target proteins. Results Results indicated that punicalagin decreased NB4 and MOLT-4 cell viability in a dose-dependent manner. Punicalagin, in combination with daunorubicin, exhibited synergistic cytotoxic effects. Punicalagin induced apoptosis through the upregulation of caspase-3/-8/-9, Bax and the downregulation of Bcl-2 expression. Punicalagin also promoted autophagy via the downregulation of mTOR and the upregulation of ULK1 expression. Cyclooxygenase-2 and toll-like receptor 4 were found to be involved in punicalagin-induced cell death in punicalagin-targeted protein interactions. Conclusions These results suggest that punicalagin exerts cytotoxic activities by suppressing proliferation and promoting apoptosis and autophagy by activating the caspase cascade, altering Bax and Bcl-2, and regulating autophagy via mTOR/ULK1 signaling.

Anticancer Activity of Neosetophomone B, An Aquatic Fungal Secondary Metabolite, Against Hematological Malignancie S

Cancer is one of the most life threatening diseases, causing nearly 13% death in the worldwide. Leukemia, cancer of the hematopoetic cells is the main cause of cancer death in adults and children. Therapeutic agents used in treatment of cancer are known to have narrow therapeutic window and tendency to develop resistance against some cancer cell lines thus, proposing a need to discover some novel agents to treat cancer. In the present study we investigated the anticancer activity of Neosetophomone B(NSP-B), an aquatic fungal metabolite isolated from Neosetophoma sp against leukemic cells (K562 and U937). MTT results demonstrated a dose dependent inhibition of cell proliferation in K562 and U937 cell lines. Annexin staining using flow cytometry indicated that NSP-B treatment cause a dose dependent apoptosis in leukemic cells.Western blot analysis showed that NSP-B mediated apoptosis involves sequential activation of caspase 9, 3 and poly (ADP-ribose) polymerase (PARP) cleavage. Furthermore NSP-B treatment of leukemic cells resulted in upregulation of pro-apoptotic proteins (Bax) with downregulation of anti-apoptotic proteins ( Bcl-2 ).Thus, present study focuses on exploring the mechanism of anticancer activity of NSP-B on leukemic cells, raising the possibility of its use as a novel therapeutic agent for hematological malignancies. Results: We sought to determine whether NSP-B suppresses the growth of leukemic cell lines. We tested a panel of leukemic cell lines with different doses of NSP-B. Cell viability decreased in a concentration-dependent manner in K562 and U937 cell lines. NSP-B induced apoptosis in K562 and U937 cell lines via downregulation of anti-apoptotic proteins and enhancement of pro-apoptotic proteins. NSP-B induced the activation of caspase cascade signaling pathway. Altogether our results suggest that the NSP-B plays an important role in apoptosis in leukemic cell lines .Conclusions: Our data provides insight on anticancer activities of NSP-B in leukemic cell lines (K562 and U937). NSP-B inhibit cell viability via inducing apoptosis. The NSP-B mediated apoptosis occurs via downregulation of anti-apoptotic proteins and enhancement of pro-apototic proteins, thereby activating the caspase-cascade signaling. Further studies are required to elicit role of NSP-B in regulating molecular pathway involved in the progression of cancer. Taken together, above results suggest that NSP-B may have a future therapeutic role in leukemia and possibly other hematological malignancies.

Co-Treatments of Edible Curcumin from Turmeric Rhizomes and Chemotherapeutic Drugs on Cytotoxicity and FLT3 Protein Expression in Leukemic Stem Cells

This study aims to enhance efficacy and reduce toxicity of the combination treatment of a drug and curcumin (Cur) on leukemic stem cell and leukemic cell lines, including KG-1a and KG-1 (FLT3+ LSCs), EoL-1 (FLT3+ LCs), and U937 (FLT3− LCs). The cytotoxicity of co-treatments of doxorubicin (Dox) or idarubicin (Ida) at concentrations of the IC10–IC80 values and each concentration of Cur at the IC20, IC30, IC40, and IC50 values (conditions 1, 2, 3, and 4) was determined by MTT assays. Dox–Cur increased cytotoxicity in leukemic cells. Dox–Cur co-treatment showed additive and synergistic effects in several conditions. The effect of this co-treatment on FLT3 expression in KG-1a, KG-1, and EoL-1 cells was examined by Western blotting. Dox–Cur decreased FLT3 protein levels and total cell numbers in all the cell lines in a dose-dependent manner. In summary, this study exhibits a novel report of Dox–Cur co-treatment in both enhancing cytotoxicity of Dox and inhibiting cell proliferation via FLT3 protein expression in leukemia stem cells and leukemic cells. This is the option of leukemia treatment with reducing side effects of chemotherapeutic drugs to leukemia patients.

From Descriptive to Functional Genomics of Leukemias Focusing on Genome Engineering Techniques

Genome engineering makes the precise manipulation of DNA sequences possible in a cell. Therefore, it is essential for understanding gene function. Meganucleases were the start of genome engineering, and it continued with the discovery of Zinc finger nucleases (ZFNs), followed by Transcription activator-like effector nucleases (TALENs). They can generate double-strand breaks at a desired target site in the genome, and therefore can be used to knock in mutations or knock out genes in the same way. Years later, genome engineering was transformed by the discovery of clustered regularly interspaced short palindromic repeats (CRISPR). Implementation of CRISPR systems involves recognition guided by RNA and the precise cleaving of DNA molecules. This property proves its utility in epigenetics and genome engineering. CRISPR has been and is being continuously successfully used to model mutations in leukemic cell lines and control gene expression. Furthermore, it is used to identify targets and discover drugs for immune therapies. The descriptive and functional genomics of leukemias is discussed in this study, with an emphasis on genome engineering methods. The CRISPR/Cas9 system’s challenges, viewpoints, limits, and solutions are also explored.

HMP-S7 Is a Novel Anti-Leukemic Peptide Discovered from Human Milk

Chemotherapy in childhood leukemia is associated with late morbidity in leukemic survivors, while certain patient subsets are relatively resistant to standard chemotherapy. It is therefore important to identify new agents with sensitivity and selectivity towards leukemic cells, while having less systemic toxicity. Peptide-based therapeutics has gained a great deal of attention during the last few years. Here, we used an integrative workflow combining mass spectrometric peptide library construction, in silico anticancer peptide screening, and in vitro leukemic cell studies to discover a novel anti-leukemic peptide having 3+ charges and an alpha helical structure, namely HMP-S7, from human breast milk. HMP-S7 showed cytotoxic activity against four distinct leukemic cell lines in a dose-dependent manner but had no effect on solid malignancies or representative normal cells. HMP-S7 induced leukemic cell death by penetrating the plasma membrane to enter the cytoplasm and cause the leakage of lactate dehydrogenase, thus acting in a membranolytic manner. Importantly, HMP-S7 exhibited anti-leukemic effects against patient-derived leukemic cells ex vivo. In conclusion, HMP-S7 is a selective anti-leukemic peptide with promise, which requires further validation in preclinical and clinical studies.

The Tyrosine Kinase-Driven Networks of Novel Long Non-coding RNAs and Their Molecular Targets in Myeloproliferative Neoplasms

Recent research has focused on the mechanisms by which long non-coding RNAs (lncRNAs) modulate diverse cellular processes such as tumorigenesis. However, the functional characteristics of these non-coding elements in the genome are poorly understood at present. In this study, we have explored several mechanisms that involve the novel lncRNA and microRNA (miRNA) axis participating in modulation of drug response and the tumor microenvironment of myeloproliferative neoplasms (MPNs). We identified novel lncRNAs via mRNA sequencing that was applied to leukemic cell lines derived from BCR-ABL1-positive and JAK2-mutant MPNs under treatment with therapeutic tyrosine kinase inhibitors (TKI). The expression and sequence of novel LNC000093 were further validated in both leukemic cells and normal primary and pluripotent cells isolated from human blood, including samples from patients with chronic myelogenous leukemia (CML). Downregulation of LNC000093 was validated in TKI-resistant CML while a converse expression pattern was observed in blood cells isolated from TKI-sensitive CML cases. In addition to BCR-ABL1-positive CML cells, the driver mutation JAK2-V617F-regulated lncRNA BANCR axis was further identified in BCR-ABL1-negative MPNs. Further genome-wide validation using MPN patient specimens identified 23 unique copy number variants including the 7 differentially expressed lncRNAs from our database. The newly identified LNC000093 served as a competitive endogenous RNA for miR-675-5p and reversed the imatinib resistance in CML cells through regulating RUNX1 expression. The extrinsic function of LNC000093 in exosomal H19/miR-675-induced modulation for the microenvironment was also determined with significant effect on VEGF expression.

Cellular Metabolomics Profiles Associated With Drug Chemosensitivity in AML

BackgroundAcute myeloid leukemia (AML) is a hematological malignancy with a dismal prognosis. For over four decades, AML has primarily been treated by cytarabine combined with an anthracycline. Although a significant proportion of patients achieve remission with this regimen, roughly 40% of children and 70% of adults relapse. Over 90% of patients with resistant or relapsed AML die within 3 years. Thus, relapsed and resistant disease following treatment with standard therapy are the most common clinical failures that occur in treating this disease. In this study, we evaluated the relationship between AML cell line global metabolomes and variation in chemosensitivity.MethodsWe performed global metabolomics on seven AML cell lines with varying chemosensitivity to cytarabine and the anthracycline doxorubicin (MV4.11, KG-1, HL-60, Kasumi-1, AML-193, ME1, THP-1) using ultra-high performance liquid chromatography – mass spectrometry (UHPLC-MS). Univariate and multivariate analyses were performed on the metabolite peak intensity values from UHPLC-MS using MetaboAnalyst to identify cellular metabolites associated with drug chemosensitivity.ResultsA total of 1,624 metabolic features were detected across the leukemic cell lines. Of these, 187 were annotated to known metabolites. With respect to doxorubicin, we observed significantly greater abundance of a carboxylic acid (1-aminocyclopropane-1-carboxylate) and several amino acids in resistant cell lines. Pathway analysis found enrichment of several amino acid biosynthesis and metabolic pathways. For cytarabine resistance, nine annotated metabolites were significantly different in resistance vs. sensitive cell lines, including D-raffinose, guanosine, inosine, guanine, aldopentose, two xenobiotics (allopurinol and 4-hydroxy-L-phenylglycine) and glucosamine/mannosamine. Pathway analysis associated these metabolites with the purine metabolic pathway.ConclusionOverall, our results demonstrate that metabolomics differences contribute toward drug resistance. In addition, it could potentially identify predictive biomarkers for chemosensitivity to various anti-leukemic drugs. Our results provide opportunity to further explore these metabolites in patient samples for association with clinical response.

Urolithin A and B Alter Cellular Metabolism and Induce Metabolites Associated with Apoptosis in Leukemic Cells

Leukemia is persistently a significant cause of illness and mortality worldwide. Urolithins, metabolites of ellagic acid and ellagitannins produced by gut microbiota, showed better bioactive compounds liable for the health benefits exerted by ellagic acid and ellagitannins containing pomegranate and walnuts. Here, we assessed the potential antileukemic activities of both urolithin A and urolithin B. Results showed that both urolithin A and B significantly inhibited the proliferation of leukemic cell lines Jurkat and K562, among which urolithin A showed the more prominent antiproliferative capability. Further, urolithin treatment alters leukemic cell metabolism, as evidenced by increased metabolic rate and notable changes in glutamine metabolism, one-carbon metabolism, and lipid metabolism. Next, we evidenced that both urolithins equally promoted apoptosis in leukemic cell lines. Based on these observations, we concluded that both urolithin A and B alter leukemic cell metabolome, resulting in a halt of proliferation, followed by apoptosis. The data can be used for designing new combinational therapies to eradicate leukemic cells.