Acute myeloid leukemia

Synthesis and biological evaluation of diaryl urea derivatives as FLT3 inhibitors

As a class III receptor tyrosine kinase (RTK), FMS-like tyrosine kinase 3 (FLT3) is always overexpressed in many cases of acute leukemia. This paper studies the structure-based synthesis and biological evaluation of diaryl urea derivatives as FLT3 inhibitors. Encouragingly, compounds 15b, 16b, 24a, and 24c showed excellent biological activities in a low nanomolar range. In particular, compound 16b demonstrated significant inhibitory potency against FLT3-ITD (IC₅₀ = 5.60 nM) and better antiproliferative activity than quizartinib against MV4-11 cell line (IC₅₀ = 0.176 nM). It is indicated that compound 16b for the treatment of acute myeloid leukemia could be very promising.

At the Bedside: Profiling and treating patients with CXCR4-expressing cancers

The chemokine receptor, C-X-C chemokine receptor type 4 (CXCR4) and its ligand, C-X-C motif chemokine 12, are key mediators of hematopoietic cell trafficking. Their roles in the proliferation and metastasis of tumor cells, induction of angiogenesis, and invasive tumor growth have been recognized for over 2 decades. CXCR4 is a promising target for imaging and therapy of both hematologic and solid tumors. To date, Sanofi Genzyme's plerixafor is the only marketed CXCR4 inhibitor (i.e., Food and Drug Administration-approved in 2008 for stem cell mobilization). However, several new CXCR4 inhibitors are now being investigated as potential therapies for a variety of fluid and solid tumors. These small molecules, peptides, and Abs include balixafortide (POL6326, Polyphor), mavorixafor (X4P-001, X4 Pharmaceuticals), motixafortide (BL-8040, BioLineRx), LY2510924 (Eli Lilly), and ulocuplumab (Bristol-Myers Squibb). Early clinical evidence has been encouraging, for example, with motixafortide and balixafortide, and the CXCR4 inhibitors appear to be generally safe and well tolerated. Molecular imaging is increasingly being used for effective patient selection before, or early during CXCR4 inhibitor treatment. The use of radiolabeled theranostics that combine diagnostics and therapeutics is an additional intriguing approach. The current status and future directions for radioimaging and treating patients with CXCR4-expressing hematologic and solid malignancies are reviewed. See related review - At the Bench: Pre-Clinical Evidence for Multiple Functions of CXCR4 in Cancer. J. Leukoc. Biol. xx: xx-xx; 2020.

The effects of cytarabine combined with ginsenoside compound K synergistically induce DNA damage in acute myeloid leukemia cells

AML is a kind of hematological malignant tumor that urgently requires different treatment options in order to increase the cure rate and survival rate. Cytarabine (ara-C) is currently the main drug used to treat AML patients and is usually combined with different chemotherapeutic agents. However, due to resistance to ara-C, a new combination is needed to reduce ara-C resistance and improve treatment outcome. As is known to all, ginseng is a traditional Chinese herb; compound K is the principal metabolic product of ginsenoside which also has anti-cancer activity in some cancer cells, while the mechanism is unclear. In our previous study, we found that compound K inhibited AML cell viability and induced apoptosis, and compound K combined with ara-C synergistically induced AML cell proliferation arrest. Thus, we sought to investigate the reason for this by focusing on the mitochondrial dysfunction and DNA damage. In this paper, our results provide a foundation for the clinical evaluation of concomitant administration of compound K and ara-C in order to reduce the resistance to ara-C and improve AML treatment.

Use of carbapenems and glycopeptides increases risk for Clostridioides difficile infections in acute myeloid leukemia patients undergoing intensive induction chemotherapy

Patients with acute myeloid leukemia (AML) are often exposed to broad-spectrum antibiotics and thus at high risk of Clostridioides difficile infections (CDI). As bacterial infections are a common cause for treatment-related mortality in these patients, we conducted a retrospective study to analyze the incidence of CDI and to evaluate risk factors for CDI in a large uniformly treated AML cohort. A total of 415 AML patients undergoing intensive induction chemotherapy between 2007 and 2019 were included in this retrospective analysis. Patients presenting with diarrhea and positive stool testing for toxin-producing Clostridioides difficile were defined to have CDI. CDI was diagnosed in 37 (8.9%) of 415 AML patients with decreasing CDI rates between 2013 and 2019 versus 2007 to 2012. Days with fever, exposition to carbapenems, and glycopeptides were significantly associated with CDI in AML patients. Clinical endpoints such as length of hospital stay, admission to ICU, response rates, and survival were not adversely affected. We identified febrile episodes and exposition to carbapenems and glycopeptides as risk factors for CDI in AML patients undergoing induction chemotherapy, thereby highlighting the importance of interdisciplinary antibiotic stewardship programs guiding treatment strategies in AML patients with infectious complications to carefully balance risks and benefits of anti-infective agents.

Hsa_circ_0012152 and Hsa_circ_0001857 Accurately Discriminate Acute Lymphoblastic Leukemia From Acute Myeloid Leukemia

Acute leukemia (AL) is a group of highly heterogeneous hematological malignancies. Circular RNAs (circRNAs) are covalently closed circRNA molecules implicated in the development of many diseases. However, the role of circRNAs in AL remains largely unknown. Therefore, this study aimed to identify new classification diagnostic biomarkers for subgroups of AL. The circRNA expression signatures discriminating acute lymphoblastic leukemia (ALL) from acute myeloid leukemia (AML) were identified by microarray, followed by reverse transcription quantitative polymerase chain reaction (RT-qPCR) validation. Receiver operating characteristic curve analysis was used to evaluate the diagnostic efficiencies of hsa_circ_0001857 and hsa_circ_0012152, and hsa_circ_0012152 was selected for Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analysis. The results showed that the circRNA expression profiles, hsa_circ_0001857, and hsa_circ_0012152 could clearly discriminate ALL from AML. The target genes of hsa_circ_0012152 might be involved in biological processes, such as myeloid cell differentiation, covalent chromatin modification, histone modification, and rat sarcoma (Ras) protein signal transduction, and participate in pathways such as mitogen-activated protein kinase (MAPK) and phosphatidylinositol 3′-kinase (PI3K)-Akt signaling pathway. Hsa_circ_0012152 might be involved in the initiation and development of AML through miR-491-5p/epidermal growth factor receptor (EGFR)/MAPK1 or miR-512-3p/EGFR/MAPK1 axis. Our results showed that circRNA expression profiles and specifically expressed circRNAs were promising classification biomarkers to designate AL into ALL or AML.

Cranberry A-type proanthocyanidins selectively target acute myeloid leukemia cells

Most elderly patients affected with acute myeloid leukemia (AML) will relapse and die of their disease even after achieving complete remission, thus emphasizing the urgent need for new therapeutic approaches with minimum toxicity to normal hematopoietic cells. Cranberry (Vaccinium spp.) extracts have exhibited anticancer and chemopreventive properties that have been mostly attributed to A-type proanthocyanidin (A-PAC) compounds. A-PACs, isolated from a commercially available cranberry extract, were evaluated for their effects on leukemia cell lines, primary AML samples, and normal CD34+ cord blood specimens. Our results indicated potent and specific antileukemia activity in vitro. In addition, the antileukemia activity of A-PACs extended to malignant progenitor and stem cell populations, sparing their normal counterparts. The antileukemia effects of A-PACs were also observed in vivo using patient derived xenografts. Surprisingly, we found that the mechanism of cell death was driven by activation of NF-κB. Overall, our data suggest that A-PACs could be used to improve treatments for AML by targeting leukemia stem cells through a potentially novel pathway.

CD33-Targeted Therapies: Beating the Disease or Beaten to Death?

CD33 is a transmembrane protein that is found on cells of myeloid lineage. It is also intensely expressed on acute myeloid leukemia (AML) progenitor cells but not on normal stem cells. It internalizes on binding and dimerization, making it a specific and ideal target for AML therapeutics and drug delivery. Several targeted therapies have been tested and many are still currently in development. Gemtuzumab ozogamicin was the first and only CD33-directed antibody-drug conjugate to be US Food and Drug Administration approved for AML. Other targeted agents have not achieved such success. Promising new strategies include cellular therapy mechanisms and linker molecules. This is an exciting target that requires a considerable amount of precision to yield clinical benefit.

Identification and Development of 1,4-Diaryl-1,2,3-triazolo-Based Ureas as Novel FLT3 Inhibitors

A class of 1,4-diaryl-1,2,3-triazolo-based ureas were synthesized and developed as novel FLT3 inhibitors. The representative compound 28 strongly inhibited FLT3-ITD kinase (IC₅₀ = 32.8 nM) and isogenic BaF3-FLT3-ITD cell (GI₅₀ = 0.6 nM). It exhibited potent inhibition against FLT3-ITD positive MV4-11 (GI₅₀ = 3.0 nM) and MOLM-13 (GI₅₀ = 5.9 nM) cell lines and high selectivity over FLT3-WT cell lines. It also displayed good pharmacokinetics properties and demonstrated promising oral in vivo efficacy in a MV4-11 cell xenografted mouse model. It might be a potent lead compound for further development to treat FLT3-ITD driven acute myloid leukemia.

Prognostic significance of serial molecular annotation in myelodysplastic syndromes (MDS) and secondary acute myeloid leukemia (sAML)

The implementation of next-generation sequencing (NGS) has influenced diagnostic, prognostic, and therapeutic decisions in myeloid malignancies. However, the clinical relevance of serial molecular annotation in patients with myelodysplastic syndrome (MDS) undergoing active treatment is unknown. MDS or secondary acute myeloid leukemia (sAML) patients who had at least two NGS assessments were identified. Outcomes according to mutation clearance (NGS-) on serial assessment were investigated. Univariate and multivariate Cox regression models were used to evaluate the prognostic impact of NGS trajectory on overall survival (OS). A total of 157 patients (MDS [n = 95]; sAML [n = 52]; CMML [n = 10]) were identified, with 93% of patients receiving treatment between NGS assessments. Magnitude of VAF delta from baseline was significantly associated with quality of response to treatment. Patients achieving NGS- had significantly improved OS compared to patients with mutation persistence (median OS not reached vs. 18.5 months; P = 0.002), which was confirmed in multivariate analysis (HR,0.14; 95%CI = 0.03-0.56; P = 0.0064). Serial TP53 VAF evaluation predicts outcomes with TP53 clearance representing an independent covariate for superior OS (HR,0.22; 95%CI = 0.05-0.99; P = 0.048). Collectively, our study highlights the clinical value of serial NGS during treatment and warrants prospective validation of NGS negativity as a biomarker for treatment outcome.

Myeloproliferative Disorder with Intraoral Lesions in an Olive Baboon (Papio anubis)

Spontaneous myeloid leukemia is rarely reported in non-human primates. We report a case of myeloproliferative disorder suggestive of acute myeloid leukemia with intraoral lesions in an olive baboon (Papio anubis). Clinical pathology, radiology, gross examination (pre-mortem and post-mortem), histopathology, and immunohistochemistry findings are provided.

Downregulation of GLI3 Expression Mediates Chemotherapy Resistance in Acute Myeloid Leukemia

Aberrant activation of the hedgehog (HH) pathway is observed in many neoplasms, including acute myeloid leukemia (AML). The glioma-associated oncogene homolog (GLI) transcription factors are the main downstream effectors of the HH signaling cascade and are responsible for the proliferation and maintenance of leukemic stem cells, which support chemotherapy resistance and leukemia relapse. Cytarabine (Ara-C)-resistant variants of AML cell lines were established through long-term cultivation with successively increasing Ara-C concentrations. Subsequently, differences in GLI expression were analyzed by RT-qPCR. GLI3 mRNA levels were detectable in parental Kasumi-1, OCI-AML3, and OCI-AML5 cells, whereas GLI3 expression was completely silenced in all resistant counterparts. Therefore, we generated GLI3-knockdown cell lines using small hairpin RNAs (shRNA) and evaluated their sensitivity to Ara-C in vitro. The knockdown of GLI3 partly abolished the effect of Ara-C on colony formation and induction of apoptosis, indicating that GLI3 downregulation results in Ara-C resistance. Moreover, we analyzed the expression of several genes involved in Ara-C metabolism and transport. Knockdown of GLI3 resulted in the upregulation of SAM and HD domain-containing protein 1 (SAMHD1), cytidine deaminase (CDA), and ATP-binding cassette C11 (ABCC11)/multidrug resistance-associated protein 8 (MRP8), each of which has been identified as a predictive marker for Ara-C response in acute myeloid leukemia. Our results demonstrate that GLI3 downregulation is a potential mechanism to induce chemotherapy resistance in AML.

Migration arrest of chemoresistant leukemia cells mediated by MRTF-SRF pathway

Background

Dormant chemotherapy-resistant leukemia cells can survive for an extended period before relapse. Nevertheless, the mechanisms underlying the development of chemoresistance in vivo remain unclear.

Methods

Using intravital bone imaging, we characterized the behavior of murine acute myeloid leukemia (AML) cells (C1498) in the bone marrow before and after chemotherapy with cytarabine.

Results

Proliferative C1498 cells exhibited high motility in the bone marrow. Cytarabine treatment impaired the motility of residual C1498 cells. However, C1498 cells regained their migration potential after relapse. RNA sequencing revealed that cytarabine treatment promoted MRTF-SRF pathway activation. MRTF inhibition using CCG-203971 augmented the anti-tumor effects of chemotherapy in our AML mouse model, as well as suppressed the migration of chemoresistant C1498 cells.

Conclusions

These results provide novel insight into the role of cell migration arrest on the development of chemoresistance in AML, as well as provide a strong rationale for the modulation of cellular motility as a therapeutic target for refractory AML.

A comprehensive review of genetic alterations and molecular targeted therapies for the implementation of personalized medicine in acute myeloid leukemia

Acute myeloid leukemia (AML) is an extremely heterogeneous disease defined by the clonal growth of myeloblasts/promyelocytes not only in the bone marrow but also in peripheral blood and/or tissues. Gene mutations and chromosomal abnormalities are usually associated with aberrant proliferation and/or block in the normal differentiation of hematopoietic cells. So far, the combination of cytogenetic profiling and molecular and gene mutation analyses remains an essential tool for the classification, diagnosis, prognosis, and treatment for AML. This review gives an overview on how the development of novel innovative technologies has allowed us not only to detect the genetic alterations as early as possible but also to understand the molecular pathogenesis of AML to develop novel targeted therapies. We also discuss the remarkable advances made during the last decade to understand the AML genome both at primary and relapse diseases and how genetic alterations might influence the distinct biological groups as well as the clonal evolution of disease during the diagnosis and relapse. Also, the review focuses on how the persistence of epigenetic gene mutations during morphological remission is associated with relapse. It is suggested that along with the prognostic and therapeutic mutations, the novel molecular targeted therapies either approved by FDA or those under clinical trials including CART-cell therapy would be of immense importance in the effective management of AML.

TXNIP induces growth arrest and enhances ABT263-induced apoptosis in mixed-lineage leukemia-rearranged acute myeloid leukemia cells

Thioredoxin‐interacting protein (TXNIP) has been widely recognized as a tumor suppressor in various cancers, including liver, breast, and thyroid cancers. Although TXNIP is epigenetically silenced in acute myeloid leukemia (AML) cells, as in many cancer cells, its role in leukemogenesis remains elusive. Mixed‐lineage leukemia (MLL) gene rearrangements in AML are associated with poor prognosis, and the development of a new treatment method is eagerly anticipated. In this study, we first reveal that lower expression of TXNIP is correlated with shortened overall survival periods in AML patients. Moreover, we demonstrated that TXNIP overexpression significantly suppresses proliferation in AML cells harboring MLL fusion genes. TXNIP promotes autophagy by increasing expression of the autophagy protein, Beclin 1, and lipidation of LC3B. We also show that TXNIP overexpression combined with ABT263, a potent inhibitor of Bcl‐2 and Bcl‐xL, is highly effective at inducing cell death in MLL‐rearranged (MLL‐r) AML cells. In summary, this study provides insights into the molecular mechanism of TXNIP‐mediated tumor suppression and furthermore underscores the potential of TXNIP as a promising therapeutic target for MLL‐r AML.

Noninvasive prenatal testing detected acute myeloid leukemia in paucisymptomatic pregnant patient

To the authors' best knowledge, this is the first report of acute myeloid leukemia (AML) detected by noninvasive prenatal testing. This was an aggressive case that otherwise would have been difficult to characterize due to disadvantages of "gold‐standard" techniques.

The efficacy and safety of daunorubicin versus idarubicin combined with cytarabine for induction therapy in acute myeloid leukemia: A meta-analysis of randomized clinical trials

OBJECTIVE

To ascertain the efficacy and safety of daunorubicin combined with cytarabine comparing with idarubicin combined with cytarabine as a standard induction therapy for acute Myeloid leukemia by a meta-analysis.

METHODS

The randomized controlled trials included were retrieved from PubMed, Embase, and Cochrane library. We evaluated and cross-checked the randomized clinical trials (RCTs) comparing daunorubicin combined with cytarabine (DA) and idarubicin combined with cytarabine (IA) by two reviewers independently according to Cochrane Handbook for Systematic Reviewers of Interventions. The data of meta-analysis was conducted using Review Manager 5.3 and Stata 12.0 software.

RESULTS

A total of 6 studies containing 3140 patients were included. The primary outcomes were complete remission (CR), CR in one course (CR1), CR in two courses (CR2), overall survival (OS), and relapse rate. The secondary outcomes included adverse events and cytogenetic risk in subgroup analyses. IA showed a statistically significant in CR (RR = 1.05; 95%CI = 1.00-1.09, P = .03) and CR1 (RR = 1.11; 95%CI = 1.04-1.18, P = .003), but not in CR2 (RR = 0.97; 95%CI = 0.77-1.24, P = .83), and relapse rate (RR = 1.08; 95%CI = 0.98-1.43, P = .08). In high dose daunorubicin group, OS was significantly improved with IA compared to DA (HR = 0.89, 95%CI = 0.8-1.0, P = .041, I = 0). At grade 3/4 adverse events, the difference between IA and DA was not statistically significant (infection, P = .28; cardiac toxicity, P = .15; bleeding, P = .29). In the subgroup analysis, the genotypes of the IA and DA groups were not statistically significant for comparison of CR between the two groups (P = .07).

CONCLUSION

This meta-analysis showed that IA had a better efficacy in the treatment of acute myeloid leukemia than DA, even with increased doses of DA. The OS of a standard dose of IA patients was longer than that of DA patients. Our research shows that anthracycline dose intensification of daunorubicin is of no clinically relevant benefit in AML patients comparing with a standard dose of IA. When it comes to adverse drug reactions, it is not a significant difference. Therefore, in clinical practice, IA should be the first choice for induction regimen in patients with acute myeloid leukemia.

Economic Evaluation of Azacitidine in Elderly Patients with Acute Myeloid Leukemia with High Blast Counts

BACKGROUND

Azacitidine is an hypomethylating agent widely adopted for the treatment of acute myeloid leukaemia (AML) in patients who are ineligible for curative-intent chemotherapy. Patients with low bone marrow blast counts (< 30%) experience improved survival with azacitidine, but the benefits are significantly lower in patients with > 30% blasts in the bone marrow. As such, there is uncertainty around the economic benefit of azacitidine in patients with higher blast counts.

OBJECTIVE

We present a cost-utility analysis of azacitidine in patients with AML with > 30% blasts to determine the economic value of azacitidine in this patient population from the perspective of a third-party payer.

METHODS

A Markov model was developed with a time horizon of 25 months divided into 22 cycles of 35 days each. The cost utility of azacitidine was compared with that of conventional care regimens (which include best supportive care, low-dose cytarabine and induction chemotherapy). A Canadian public healthcare system perspective was selected.

RESULTS

In the base case, the incremental cost per quality-adjusted life-year gained (incremental cost-effectiveness ratio [ICER]) for azacitidine compared with conventional care regimens was $Can160,438, year 2018 values. The estimated ICER was insensitive to a longer time horizon but sensitive to the cost of azacitidine and to assumptions relating to survival in both treatment regimens, although the ICER always remained greater than Can$80,000 in all scenarios.

CONCLUSION

Azacitidine is unlikely to be cost effective given that the estimated ICER exceeds the willingness to pay commonly used in the Canadian healthcare system.

Design of Hydrazide-Bearing HDACIs Based on Panobinostat and Their p53 and FLT3-ITD Dependency in Antileukemia Activity

Here, we present a new series of hydrazide-bearing class I selective HDAC inhibitors designed based on panobinostat. The cap, linker, and zinc-binding group were derivatized to improve HDAC affinity and antileukemia efficacy. Lead inhibitor 13a shows picomolar or low nanomolar IC₅₀ values against HDAC1 and HDAC3 and exhibits differential toxicity profiles toward multiple cancer cells with different FLT3 and p53 statuses. 13a indirectly inhibits the FLT3 signaling pathway and down-regulates master antiapoptotic proteins, resulting in the activation of pro-caspase3 in wt-p53 FLT3-ITD MV4-11 cells. While in the wt-FLT3 and p53-null cells, 13a is incapable of causing apoptosis at a therapeutic concentration. The MDM2 antagonist and the proteasome inhibitor promote 13a-triggered apoptosis by preventing p53 degradation. Furthermore, we demonstrate that apoptosis rather than autophagy is the key contributing factor for 13a-triggered cell death. When compared to panobinostat, 13a is not mutagenic and displays superior in vivo bioavailability and a higher AUC_0-inf value.

Reducing the red blood cell transfusion threshold from 8·0 g/dl to 7·0 g/dl in acute myeloid leukaemia patients undergoing induction chemotherapy reduces transfusion rates without adversely affecting patient outcome

BACKGROUND AND OBJECTIVES

Red blood cell (RBC) transfusions are needed by almost every acute myeloid leukaemia (AML) patient undergoing induction chemotherapy and constitute a cornerstone in supportive measures for cancer patients in general. Randomized controlled trials have shown non-inferiority or even superiority of restrictive transfusion guidelines over liberal transfusion guidelines in specific clinical situations outside of medical oncology. In this study, we analysed whether more restrictive RBC transfusion reduces blood use without affecting hard outcomes.

MATERIALS AND METHODS

A total of 352 AML patients diagnosed between 2007 and 2018 and undergoing intensive induction chemotherapy were included in this retrospective analysis. In the less restrictive transfusion group, patients received RBC transfusion for haemoglobin levels below 8 g/dl (2007-2014). In the restrictive transfusion group, patients received RBC transfusion for haemoglobin levels below 7 g/dl (2016-2018). Liberal transfusion triggers were never endorsed.

RESULTS

A total of 268 (76·1%) and 84 (23·9%) AML patients fell into the less restrictive and restrictive transfusion groups, respectively. The less restrictive transfusion group had 1 g/dl higher mean haemoglobin levels, received their first RBC transfusions earlier and needed 1·5 more units of RBC during the hospital stay of induction chemotherapy. Febrile episodes, C-reactive protein levels, admission to the intensive care unit, length of hospital stay as well as response and survival rates did not differ between the two cohorts.

CONCLUSION

From our retrospective analysis, we conclude that a more restrictive transfusion trigger does not affect important outcomes of AML patients. The opportunity to test possible effects of the more severe anaemia in the restrictive transfusion group on quality of life was missed.

Recent advances in FLT3 inhibitors for acute myeloid leukemia

Fms-like tyrosine kinase-3 (FLT3) mutations occur in approximately 30% of acute myeloid leukemia (AML) cases, suggesting FLT3 as an attractive target for AML treatment. Early FLT3 inhibitors enhance antileukemia efficacy by inhibiting multiple targets, and thus had stronger off-target activity, increasing their toxicity. Recently, a number of potent and selective FLT3 inhibitors have been developed, many of which are effective against multiple mutations. This review outlines the evolution of AML-targeting FLT3 inhibitors by focusing on their chemotypes, selectivity and activity over FLT3 wild-type and FLT3 mutations as well as new techniques related to FLT3. Compounds that currently enter the late clinical stage or have entered the market are also briefly reported.

Designing combination therapies using multiple optimal controls

Strategic management of populations of interacting biological species routinely requires interventions combining multiple treatments or therapies. This is important in key research areas such as ecology, epidemiology, wound healing and oncology. Despite the well developed theory and techniques for determining single optimal controls, there is limited practical guidance supporting implementation of combination therapies. In this work we use optimal control theory to calculate optimal strategies for applying combination therapies to a model of acute myeloid leukaemia. We present a versatile framework to systematically explore the trade-offs that arise in designing combination therapy protocols using optimal control. We consider various combinations of continuous and bang-bang (discrete) controls, and we investigate how the control dynamics interact and respond to changes in the weighting and form of the pay-off characterising optimality. We demonstrate that the optimal controls respond non-linearly to treatment strength and control parameters, due to the interactions between species. We discuss challenges in appropriately characterising optimality in a multiple control setting and provide practical guidance for applying multiple optimal controls. Code used in this work to implement multiple optimal controls is available on GitHub.

Utilizing Synergistic Potential of Mitochondria-Targeting Drugs for Leukemia Therapy

Acute myeloid leukemia (AML) is an aggressive group of cancers with high mortality rates and significant relapse risks. Current treatments are insufficient, and new therapies are needed. Recent discoveries suggest that AML may be particularly sensitive to chemotherapeutics that target mitochondria. To further investigate this sensitivity, six compounds that target mitochondria [IACS-010759, rotenone, cytarabine, etoposide, ABT-199 (venetoclax), and carbonyl cyanide m-chlorophenylhydrazone] were each paired with six compounds with other activities, including tyrosine kinase inhibitors (midostaurin and dasatinib), glycolytic inhibitors (2-deoxy-D-glucose, 3-bromopyruvate, and lonidamine), and the microtubule destabilizer vinorelbine. The 36 resulting drug combinations were tested for synergistic cytotoxicity against MOLM-13 and OCI-AML2 AML cell lines. Four combinations (IACS-010759 with vinorelbine, rotenone with 2-deoxy-D-glucose, carbonyl cyanide m-chlorophenylhydrazone with dasatinib, and venetoclax with lonidamine) showed synergistic cytotoxicity in both AML cell lines and were selective for tumor cells, as survival of healthy PBMCs was dramatically higher. Among these drug pairs, IACS-010759/vinorelbine decreased ATP level and impaired mitochondrial respiration and coupling efficiency most profoundly. Some of these four treatments were also effective in K-562, KU812 (chronic myelogenous leukemia) and CCRF-CEM, MOLT-4 (acute lymphoblastic leukemia) cells, suggesting that these treatments may have value in treating other forms of leukemia. Finally, two of the four combinations retained high synergy and strong selectivity in primary AML cells from patient samples, supporting the potential of these treatments for patients.

Carbohydrates: Potential Sweet Tools Against Cancer

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Cancer, one of the most devastating degenerative diseases nowadays, is one of the main targets in Medicinal Chemistry and Pharmaceutical industry. Due to the significant increase in the incidence of cancer within world population, together with the complexity of such disease, featured with a multifactorial nature, access to new drugs targeting different biological targets connected to cancer is highly necessary.

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Among the vast arsenal of compounds exhibiting antitumor activities, this review will cover the use of carbohydrate derivatives as privileged scaffolds. Their hydrophilic nature, together with their capacity of establishing selective interactions with biological receptors located on cell surface, involved in cell-to-cell communication processes, has allowed the development of an ample number of new templates useful in cancer treatment.

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Their intrinsic water solubility has allowed their use as of pro-drug carriers for accessing more efficiently the pharmaceutical targets. The preparation of glycoconjugates in which the carbohydrate is tethered to a pharmacophore has also allowed a better permeation of the drug through cellular membranes, in which selective interactions with the carbohydrate motifs are involved. In this context, the design of multivalent structures (e.g. gold nanoparticles) has been demonstrated to enhance crucial interactions with biological receptors like lectins, glycoproteins that can be involved in cancer progression.

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Moreover, the modification of the carbohydrate structural motif, by incorporation of metal complexes, or by replacing their endocyclic oxygen, or carbon atoms with heteroatoms has led to new antitumor agents.

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Such diversity of sugar-based templates with relevant antitumor activity will be covered in this review.

Indirect comparison of azacitidine and decitabine for the therapy of elderly patients with acute myeloid leukemia: a systematic review and network meta-analysis

Background

The DNA hypomethylating agents (HMAs) decitabine and azacitidine have been widely used in the management of elderly patients with acute myeloid leukemia (AML). However, no direct clinical trials have been carried out to compare the two agents. A systematic review and network meta-analysis were performed to indirectly compare the efficacy and safety of decitabine and azacitidine in elderly AML patients.

Methods

We systematically searched PubMed, Medline, Web of Science, Embase and Cochrane Library through May 14, 2019. Randomized controlled trials on elderly AML patients comparing the efficacy and safety between decitabine and azacitidine, or comparing one of HMAs to standard supportive care or placebo were selected. The major outcomes of interest were performed with methods of adjusted indirect comparison and the fixed effect model.

Results

Only three RCTs including a total number of 1086 patients were identified. Direct comparisons showed that azacitidine significantly reduced mortality (RR = 0.90, 95% CI 0.83–0.97) while decitabine was not significantly associated with lower mortality (RR = 0.97, 95% CI 0.92–1.02) compared to the conventional care regimen (CCR). In addition, for the indirect method, azacitidine significantly reduced mortality compared to decitabine (RR = 0.83 95% CI 0.77–0.90) and was more likely to improve complete response (CR) (RR = 1.66, 95% CI 1.17–2.35, low-certainty evidence). No statistical significance was found for the other studied outcomes.

Conclusions

Compared to CCR, decitabine and azacitidine can promote studied outcomes in elderly AML patients. Indirect evidence with low certainty was used to compare these two agents. The superiority of either agent cannot be confirmed, and head-to-head clinical trials are still required.

A non-proliferative role of pyrimidine metabolism in cancer

Background

Nucleotide metabolism is a critical pathway that generates purine and pyrimidine molecules for DNA replication, RNA synthesis, and cellular bioenergetics. Increased nucleotide metabolism supports uncontrolled growth of tumors and is a hallmark of cancer. Agents inhibiting synthesis and incorporation of nucleotides in DNA are widely used as chemotherapeutics to reduce tumor growth, cause DNA damage, and induce cell death. Thus, the research on nucleotide metabolism in cancer is primarily focused on its role in cell proliferation. However, in addition to proliferation, the role of purine molecules is established as ligands for purinergic signals. However, so far, the role of the pyrimidines has not been discussed beyond cell growth.

Scope of the review

In this review we present the key evidence from recent pivotal studies supporting the notion of a non-proliferative role for pyrimidine metabolism (PyM) in cancer, with a special focus on its effect on differentiation in cancers from different origins.

Major conclusion

In leukemic cells, the pyrimidine catabolism induces terminal differentiation toward monocytic lineage to check the aberrant cell proliferation, whereas in some solid tumors (e.g., triple negative breast cancer and hepatocellular carcinoma), catalytic degradation of pyrimidines maintains the mesenchymal-like state driven by epithelial-to-mesenchymal transition (EMT). This review further broadens this concept to understand the effect of PyM on metastasis and, ultimately, delivers a rationale to investigate the involvement of the pyrimidine molecules as oncometabolites. Overall, understanding the non-proliferative role of PyM in cancer will lead to improvement of the existing antimetabolites and to development of new therapeutic options.

Roscovitine enhances All-trans retinoic acid (ATRA)-induced leukemia cell differentiation: Novel effects on signaling molecules for a putative Cdk2 inhibitor

All-trans retinoic acid (ATRA)-based differentiation therapy has been unsuccessful in treating t(15;17) negative acute myeloid leukemia (AML) patients, motivating interest in combination therapies using ATRA plus other agents. Using the t (15, 17) negative HL-60 human myeloblastic leukemia model, we find that the cyclin-dependent kinase (CDK) inhibitor, roscovitine, augments signaling by an ATRA-induced macromolecular signalsome that propels differentiation and enhances ATRA-induced differentiation. Roscovitine co-treatment enhanced ATRA-induced expression of pS259- pS289/296/301- pS621-c-Raf, pS217/221-Mek, Src Family Kinases (SFKs) Lyn and Fgr and SFK Y416 phosphorylation, adaptor proteins c-Cbl and SLP-76, Vav, and acetylated 14-3-3 in the signalsome. Roscovitine enhanced ATRA-induced c-Raf interaction with Lyn, Vav, and c-Cbl. Consistent with signalsome hyper-activation, roscovitine co-treatment enhanced ATRA-induced G1/0 arrest and expression of differentiation markers, CD11b, ROS and p47 Phox. Because roscovitine regulated Lyn expression, activation and partnering, a stably transfected Lyn knockdown was generated from wt-parental cells to investigate its function in ATRA-induced differentiation. Lyn-knockdown enhanced ATRA-induced up-regulation of key signalsome molecules, c-Raf, pS259-c-Raf, pS289/296/301-c-Raf, Vav1, SLP-76, and Fgr, but with essentially total loss of pY416-SFK. Compared to ATRA-treated wt-parental cells, differentiation markers p47 phox, CD11b, G1/G0 arrest and ROS production were enhanced in ATRA-treated Lyn-knockdown stable transfectants, and addition of roscovitine further enhanced these ATRA-inducible markers. The Lyn-knockdown cells expressed slightly higher c-Raf, pS259-c-Raf, pS289/296/301-c-Raf, and SLP-76 than wt-parental cells, and this was associated with enhanced ATRA-induced upregulation of Fgr and cell differentiation, consistent with heightened signaling, suggesting that enhanced Fgr may have compensated for loss of Lyn to enhance differentiation in the Lyn-knockdown cells.

Vitamin D Receptor Controls Cell Stemness in Acute Myeloid Leukemia and in Normal Bone Marrow

Vitamin D (VD) is a known differentiating agent, but the role of VD receptor (VDR) is still incompletely described in acute myeloid leukemia (AML), whose treatment is based mostly on antimitotic chemotherapy. Here, we present an unexpected role of VDR in normal hematopoiesis and in leukemogenesis. Limited VDR expression is associated with impaired myeloid progenitor differentiation and is a new prognostic factor in AML. In mice, the lack of Vdr results in increased numbers of hematopoietic and leukemia stem cells and quiescent hematopoietic stem cells. In addition, malignant transformation of Vdr-/- cells results in myeloid differentiation block and increases self-renewal. Vdr promoter is methylated in AML as in CD34+ cells, and demethylating agents induce VDR expression. Association of VDR agonists with hypomethylating agents promotes leukemia stem cell exhaustion and decreases tumor burden in AML mouse models. Thus, Vdr functions as a regulator of stem cell homeostasis and leukemic propagation.

High serum extracellular vesicle miR-10b expression predicts poor prognosis in patients with acute myeloid leukemia

BACKGROUND

Increasing evidence have demonstrated that serum extracellular vesicle microRNAs (EV-miRNAs) are promising noninvasive biomarkers for various cancer types.

OBJECTIVE

In this study, we aimed to investigate and evaluate the potential clinical significance of serum EV-miR-10b for acute myeloid leukemia (AML).

METHODS

Blood samples were collected from a cohort of 95 de novo AML patients and 80 healthy individuals. Of all AML patients, 51 patients were considered as cytogenetic normal AML (CN-AML). Quantitative reverse-transcription polymerase chain reaction (qRT-PCR) was performed to measure the expression levels of serum EV-miR-10b.

RESULTS

The extracellular vesicles we extracted from the serum samples were positive for EV/exosome markers including TSG101, CD63, Flotillin-1 and CD9. The expression levels of serum EV-miR-10b were significantly higher in AML/CN-AML patients than healthy controls. In addition, serum EV-miR-10b expression was strongly correlated with aggressive clinical characteristics. Moreover, receiver operating characteristic analysis showed serum EV-miR-10b yielded an area under the curve of 0.875, with 77.89% specificity and 82.50% sensitivity in identifying AML patients from normal controls. Furthermore, AML patients with higher serum EV-miR-10b expression had significantly shorter survival and serum EV-miR-10b was demonstrated to be an independent prognostic marker for overall survival in AML.

CONCLUSIONS

Taken together, serum EV-miR-10b might serve as a promising biomarker for predicting the prognosis of AML.

Acute Myeloid Leukemia: Aging and Epigenetics

Acute myeloid leukemia (AML) is an aggressive hematological disorder mainly affecting people of older age. AML initiation is primarily attributed to mutations in crucial cellular regulators such as epigenetic factors, transcription factors, and signaling genes. AML’s aggressiveness and responsiveness to treatment depends on the specific cell type where leukemia first arose. Aged hematopoietic cells are often genetically and/or epigenetically altered and, therefore, present with a completely different cellular context for AML development compared to young cells. In this review, we summarize key aspects of AML development, and we focus, in particular, on the contribution of cellular aging to leukemogenesis and on current treatment options for elderly AML patients. Hematological disorders and leukemia grow exponentially with age. So far, with conventional induction therapy, many elderly patients experience a very poor overall survival rate requiring substantial social and medical costs during the relatively few remaining months of life. The global population’s age is increasing rapidly without an acceptable equal growth in therapeutic management of AML in the elderly; this is in sharp contrast to the increase in successful therapies for leukemia in younger patients. Therefore, a focus on the understanding of the biology of aging in the hematopoietic system, the development of appropriate research models, and new therapeutic approaches are urged.

DOT1L: a key target in normal chromatin remodelling and in mixed-lineage leukaemia treatment

Methylation of histone 3 at lysine 79 (H3K79) is one of the principal mechanisms involved in gene expression. The histone methyltransferase DOT1L, which mono-, di- and trimethylates H3K79 using S-adenosyl-L-methionine as a co-factor, is involved in cell development, cell cycle progression, and DNA damage repair. However, changes in normal expression levels of this enzyme are found in prostate, breast, and ovarian cancer. High levels of H3K79me are also detected in acute myeloid leukaemia patients bearing MLL rearrangements (MLL-r). MLL translocations are found in approximately 80% of paediatric patients, leading to poor prognosis. DOT1L is recruited on DNA and induces hyperexpression of HOXA9 and MEIS1. Based on these findings, selective drugs have been developed to induce apoptosis in MLL-r leukaemia cells by specifically inhibiting DOT1L. The most potent DOT1L inhibitor pinometostat has been investigated in Phase I clinical trials for treatment of paediatric and adult patients with MLL-driven leukaemia, showing promising results.

Gingival hyperplasia as an early manifestation of acute myeloid leukemia. A retrospective review

Background

We study the prevalence of acute myeloid leukemia (AML) among patients with severe gingival enlargement.

Material and Methods

We retrospective reviewed the clinical records of patients with severe gingival enlargement, between 2011 and 2018. The Saxer and Mühlemann index were used to measure inflammation and gingival bleeding. The degree of dental mobility was measured by the Nyman and Lindhe technique.

Results

A correlation analysis was carried out to test whether there were any associations among the different variables. In the sample of 117 patients the mean gingival bleeding index was ≥3 and the degree of dental mobility ≥2.3. 1.7% of patients, with severe gingival hyperplasia were diagnosed with AML. We found a significant association between gingival bleeding and aging (p<0.001) and a trend (0.54) between bleeding and suffering from AML.

Conclusions

Severe gingival enlargement, abundant gingival bleeding, and dental mobility could be early manifestations of a blood dyscrasia. Key words:Acute myeloblastic leukemia, gingival hyperplasia, bleeding, tooth motility, oral health.

An Overview on G Protein-coupled Receptor-induced Signal Transduction in Acute Myeloid Leukemia

BACKGROUND

Acute Myeloid Leukemia (AML) is a genetically heterogeneous disease characterized by uncontrolled proliferation of precursor myeloid-lineage cells in the bone marrow. AML is also characterized by patients with poor long-term survival outcomes due to relapse. Many efforts have been made to understand the biological heterogeneity of AML and the challenges to develop new therapies are therefore enormous. G Protein-coupled Receptors (GPCRs) are a large attractive drug-targeted family of transmembrane proteins, and aberrant GPCR expression and GPCR-mediated signaling have been implicated in leukemogenesis of AML. This review aims to identify the molecular players of GPCR signaling, focusing on the hematopoietic system, which are involved in AML to help developing novel drug targets and therapeutic strategies.

METHODS

We undertook an exhaustive and structured search of bibliographic databases for research focusing on GPCR, GPCR signaling and expression in AML.

RESULTS AND CONCLUSION

Many scientific reports were found with compelling evidence for the involvement of aberrant GPCR expression and perturbed GPCR-mediated signaling in the development of AML. The comprehensive analysis of GPCR in AML provides potential clinical biomarkers for prognostication, disease monitoring and therapeutic guidance. It will also help to provide marker panels for monitoring in AML. We conclude that GPCR-mediated signaling is contributing to leukemogenesis of AML, and postulate that mass spectrometrybased protein profiling of primary AML cells will accelerate the discovery of potential GPCR related biomarkers for AML.

Assessment of the Diagnostic Potential of miR-29a-3p and miR-92a-3p as Circulatory Biomarkers in Acute Myeloid Leukemia

Background:

Acute myeloid leukemia (AML) is a set of Myeloproliferative neoplasms that are identified by excessive growth of myeloid blasts and production of abnormal blood cells. AML is the most common type of acute leukemia that occurs in adults. In addition, AML progresses rapidly and is considered a fatal disease. Thus, there is an urgent need to find new targets for molecularly designed therapies. In This study, we evaluated the circulatory levels of microRNA-29a-3p (miR-29a-3p) and miR-92a-3p beside exploring the expression pattern of their target gene myeloid cell leukemia sequence1 (MCL1) to investigate the role of these molecules in AML pathophysiology and to assess their ability to diagnose AML patients.

Methods:

40 adult AML patients along with 20 healthy subjects were enrolled in this study. Plasma were separated from venous blood samples, collected on EDTA, of all individuals were used to assess circulating miRNAs’ levels. In the meantime, total RNA was extracted from isolated leukocytes and was used to quantify target mRNA transcript levels.

Results:

Our data revealed that the circulating levels of miR-29a-3p and miR-92a-3p exhibited significant reduction in 90% and 100% of AML patients, respectively, when compared to the control group (p<0.001). On the other hand, the transcript level of the target gene of these miRNAs, MCL1, showed a sharp increase in 77.5% (p<0.001) of AML patients, along with a negative correlation with its regulatory miRNAs, miR-29a-3p and miR-92a-3p.

Conclusion:

Our data validates the negative regulatory role of miR-29a-3p and miR-92a-3p to the expression levels of MCL1 in peripheral blood and indicates that these miRNAs can be used as non-invasive diagnostic markers. Furthermore, our study highlights the therapeutic potential of miR-29a-3p and miR-92a-3p to target and downregulate a very important gene (MCL1), which is highly implicated in the pathogenesis of AML.

Cauda Equina Syndrome Secondary to Diffuse Infiltration of the Cauda Equina by Acute Myeloid Leukemia: Case Report and Literature Review

BACKGROUND

Cauda equina syndrome (CES) results from the dysfunction of the lumbar, sacral, and coccygeal rootlets composing the cauda equina. The underlying etiology is most commonly compression secondary to a large herniated lumbosacral disk; however, any pathology affecting the rootlets can result in the syndrome.

METHODS

We present a rare case of CES secondary to neoplastic polyradiculitis in a patient with acute myelogenous leukemia (AML) and review the pertinent literature. A 72-year-old male with a medical history of AML presented with 2 weeks of difficulty ambulating, followed by acute-onset low back pain radiating to the buttocks bilaterally.

RESULTS

Imaging of the lumbar spine demonstrated diffuse enhancement and thickening of the cauda equina rootlets. Lumbar puncture showed numerous blasts with monocytoid features consistent with AML, and the patient was diagnosed with polyradiculopathy of the cauda equina secondary to diffuse metastatic infiltration.

CONCLUSIONS

Central nervous system involvement of leukemia is poorly understood, even though such lesions are not uncommon in advanced disease. As treatment has improved, many types of leukemia, such as AML, are believed to be curable, and patients with the disease are living longer. With improved survival, it is reasonable to suspect that such involvement by AML may become more common. Our patient is a classic presentation of CES secondary to diffuse infiltration by AML and serves as an example of this rare manifestation of hematologic malignancy.

The impact of At1r inhibition via losartan on the anti-leukaemic effects of doxorubicin in acute myeloid leukaemia

Introduction:

Bone marrow renin–angiotensin system(RAS) modulates acute myeloid leukaemia(AML).The aim of this study is to clarify the relationships between RAS and AML, and to show the effect of losartan and doxorubicin treatment in AML cell lines.

Methods:

AML cell lines including CESS, HL-60, MO-1, P31/FUJ, GDM-1 and KASUMI-3 were used as models in this study.

Results:

After treating the six AML cell lines with a combination of losartan and doxorubicin, they were divided into two groups based on their behaviour: one became more sensitive to drug treatment (Group A) and the other had no change observed in behaviour after drug treatment (Group B). In silico analyses showed that Group A is involved in cellular apoptosis, while Group B is involved in tumour angiogenesis further supporting the in vitro results.

Conclusion:

The combined treatment of the AML cell lines with losartan and doxorubicin resulted in an increase in sensitivity of some of the cell lines. Those leukaemic cells are modulated via the induction of apoptosis, whereas the other cells resistant to the drug treatment are closely related to tumour angiogenesis indicating that RAS-AT1R seems to be differently expressed in different leukaemic blast cells and tumour microenvironments. Pharmaco-biological actions of RAS inhibitors may be different in distinct leukaemic cells based on the pathological behaviour of AML genomic subtypes.

The M2 macrophage marker CD206: a novel prognostic indicator for acute myeloid leukemia

Hematological malignancies possess a distinctive immunologic microenvironment compared with solid tumors. Here, using an established computational algorithm (CIBERSORT), we systematically analyzed the overall distribution of 22 tumor-infiltrating leukocyte (TIL) populations in more than 2000 bone marrow (BM) samples from 5 major hematological malignancies and healthy controls. Focusing on significantly altered TILs in acute myeloid leukemia (AML), we found that patients with AML exhibited increased frequencies of M2 macrophages, compared to either healthy controls or the other four malignancies. High infiltration of M2 macrophages was associated with poor outcome in AML. Further analysis revealed that CD206, a M2 marker gene, could faithfully reflect variation in M2 fractions and was more highly expressed in AML than normal controls. High CD206 expression predicted inferior overall survival (OS) and event-free survival (EFS) in two independent AML cohorts. Among 175 patients with intermediate-risk cytogenetics, the survival still differed greatly between low and high CD206 expressers (OS; P < .0001; 3-year rates, 56% v 32%; EFS; P < .001; 3-year rates, 47% v 25%). When analyzed in a meta-analysis, CD206 as a continuous variable showed superior predictive performance than classical prognosticators in AML (BAALC, ERG, EVI1, MN1, and WT1). In summary, M2 macrophages are preferentially enriched in AML. The M2 marker CD206 may serve as a new prognostic marker in AML.

Disruption of gap junctions attenuates acute myeloid leukemia chemoresistance induced by bone marrow mesenchymal stromal cells

The bone marrow (BM) niche impacts the progression of acute myeloid leukemia (AML) by favoring the chemoresistance of AML cells. Intimate interactions between leukemic cells and BM mesenchymal stromal cells (BM-MSCs) play key roles in this process. Direct intercellular communications between hematopoietic cells and BM-MSCs involve connexins, components of gap junctions. We postulated that blocking gap junction assembly could modify cell–cell interactions in the leukemic niche and consequently the chemoresistance. The comparison of BM-MSCs from AML patients and healthy donors revealed a specific profile of connexins in BM-MSCs of the leukemic niche and the effects of carbenoxolone (CBX), a gap junction disruptor, were evaluated on AML cells. CBX presents an antileukemic effect without affecting normal BM-CD34⁺ progenitor cells. The proapoptotic effect of CBX on AML cells is in line with the extinction of energy metabolism. CBX acts synergistically with cytarabine (Ara-C) in vitro and in vivo. Coculture experiments of AML cells with BM-MSCs revealed that CBX neutralizes the protective effect of the niche against the Ara-C-induced apoptosis of leukemic cells. Altogether, these results suggest that CBX could be of therapeutic interest to reduce the chemoresistance favored by the leukemic niche, by targeting gap junctions, without affecting normal hematopoiesis.

Identification of prognostic genes in the acute myeloid leukemia immune microenvironment based on TCGA data analysis

Acute myeloid leukemia (AML) is a common and lethal hematopoietic malignancy that is highly dependent on the bone marrow (BM) microenvironment. Infiltrating immune and stromal cells are important components of the BM microenvironment and significantly influence the progression of AML. This study aimed to elucidate the value of immune/stromal cell-associated genes for AML prognosis by integrated bioinformatics analysis. We obtained expression profiles from The Cancer Genome Atlas (TCGA) database and used the ESTIMATE algorithm to calculate immune scores and stromal scores; we then identified differentially expressed genes (DEGs) based on these scores. Overall survival analysis was applied to reveal common DEGs of prognostic value. Subsequently, we conducted a functional enrichment analysis, generated a protein-protein interaction (PPI) network and performed an interrelation analysis of immune system processes, showing that these genes are mainly associated with the immune/inflammatory response. Finally, eight genes (CD163, CYP27A1, KCNA5, PPM1J, FOLR1, IL1R2, MYOF, VSIG2) were verified to be significantly associated with AML prognosis in the Gene Expression Omnibus (GEO) database. In summary, we identified key microenvironment-related genes that affect the outcomes of AML patients and might serve as therapeutic targets.

Discussion of Trial Designs for Biomarker Identification and Validation Through the Use of Case Studies

With the launch of the National Cancer Institute's Precision Medicine Initiative in 2015, there has been a shift to trial designs that tailor health care solutions to individual patients by using a screening platform and by moving away from the one-trial/one-biomarker-at-a-time approach. To make precision medicine a reality, it is critical to identify and validate potential biomarkers to help select patients who will truly benefit from a targeted therapy. In this article, we discuss five trial designs: enrichment, umbrella, basket, subgroup, and window of opportunity. For each trial design, we describe the design characteristics, use ongoing or completed trials as case studies, provide any recent advances to the trial design, and discuss advantages and disadvantages of each design.

Selinexor in combination with decitabine in patients with acute myeloid leukemia: results from a phase 1 study

Current treatment options for older and relapsed or refractory (R/R) acute myeloid leukemia (AML) patients are limited and represent an unmet need. Based on preclinical studies showing strong anti-leukemic effects in vivo, this phase I dose-escalation study assessed the safety and preliminary clinical activity of the oral exportin-1 inhibitor, selinexor, in combination with the hypomethylating agent, decitabine 20 mg/m², in adults with R/R AML and in older (age ≥ 60) untreated AML patients. There were no protocol-defined dose limiting toxicities. The recommended phase 2 dose of selinexor was 60 mg (∼35 mg/m²) given twice-weekly. Notable grade ≥3 toxicities included asymptomatic hyponatremia (68%), febrile neutropenia (44%), sepsis (44%), hypophosphatemia (36%), and pneumonia (28%). In 25 patients, the overall response rate was 40%. Modification of selinexor to a flat dose of 60 mg, twice-weekly for two weeks after decitabine, improved tolerability of the regimen and demonstrated preliminary clinical activity in poor-risk patients with AML.

Current Advances in Immunotherapy for Acute Leukemia: An Overview of Antibody, Chimeric Antigen Receptor, Immune Checkpoint, and Natural Killer

Recently, due to the application of hematopoietic stem cell transplantation and small molecule inhibitor, the survival of acute leukemia is prolonged. However, the 5 year survival rate remains low due to a high incidence of relapse. Immunotherapy is expected to improve the prognosis of patients with relapsed or refractory hematological malignancies because it does not rely on the cytotoxic mechanisms of conventional therapy. In this paper, the advances of immunotherapy in acute leukemia are reviewed from the aspects of Antibody including Unconjugated antibodies, Antibody-drug conjugate and Bispecific antibody, Chimeric Antigen Receptor (CARs), Immune checkpoint, Natural killer cells. The immunological features, mechanisms and limitation in clinic will be described.

PGE1-Containing Protocols Generate Mature (Leukemia-Derived) Dendritic Cells Directly from Leukemic Whole Blood

Dendritic cells (DCs) and leukemia-derived DC (DC_leu) are potent stimulators of various immunoreactive cells and they play a pivotal role in the (re-) activation of the immune system. As a potential treatment tool for patients with acute myeloid leukemia, we developed and analyzed two new PGE₁-containing protocols (Pici-_PGE1, Kit M) to generate DC/DC_leu ex vivo from leukemic peripheral blood mononuclear cells (PBMCs) or directly from leukemic whole blood (WB) to simulate physiological conditions. Pici-_PGE1 generated significantly higher amounts of DCs from leukemic and healthy PBMCs when compared to control and comparable amounts as the already established protocol Pici-_PGE2. The proportions of sufficient DC-generation were even higher after DC/DC_leu-generation with Pici-_PGE1. With Kits, it was possible to generate DCs and DC_leu directly from leukemic and healthy WB without induction of blast proliferation. The average amounts of generated DCs and DC_leu-subgroups were comparable with all Kits. The PGE₁ containing Kit M generated significantly higher amounts of mature DCs when compared to the PGE₂-containing Kit K and increased the anti-leukemic-activity. In summary PGE₁-containing protocols were suitable for generating DC/DC_leu from PBMCs as well as from WB, which reliably (re-) activated immunoreactive cells, improved the overall ex vivo anti-leukemic activity, and influenced cytokine-release-profiles.

Antibody Therapies for Acute Myeloid Leukemia: Unconjugated, Toxin-Conjugated, Radio-Conjugated and Multivalent Formats

In recent decades, therapy for acute myeloid leukemia (AML) has remained relatively unchanged, with chemotherapy regimens primarily consisting of an induction regimen based on a daunorubicin and cytarabine backbone, followed by consolidation chemotherapy. Patients who are relapsed or refractory can be treated with allogeneic hematopoietic stem-cell transplantation with modest benefits to event-free and overall survival. Other modalities of immunotherapy include antibody therapies, which hold considerable promise and can be categorized into unconjugated classical antibodies, multivalent recombinant antibodies (bi-, tri- and quad-specific), toxin-conjugated antibodies and radio-conjugated antibodies. While unconjugated antibodies can facilitate Natural Killer (NK) cell antibody-dependent cell-mediated cytotoxicity (ADCC), bi- and tri-specific antibodies can engage either NK cells or T-cells to redirect cytotoxicity against AML targets in a highly efficient manner, similarly to classic ADCC. Finally, toxin-conjugated and radio-conjugated antibodies can increase the potency of antibody therapies. Several AML tumour-associated antigens are at the forefront of targeted therapy development, which include CD33, CD123, CD13, CLL-1 and CD38 and which may be present on both AML blasts and leukemic stem cells. This review focused on antibody therapies for AML, including pre-clinical studies of these agents and those that are either entering or have been tested in early phase clinical trials. Antibodies for checkpoint inhibition and microenvironment targeting in AML were excluded from this review.

A Critical Review of Animal Models Used in Acute Myeloid Leukemia Pathophysiology

Acute myeloid leukemia (AML) is one of the most frequent, complex, and heterogeneous hematological malignancies. AML prognosis largely depends on acquired cytogenetic, epigenetic, and molecular abnormalities. Despite the improvement in understanding the biology of AML, survival rates remain quite low. Animal models offer a valuable tool to recapitulate different AML subtypes, and to assess the potential role of novel and known mutations in disease progression. This review provides a comprehensive and critical overview of select available AML animal models. These include the non-mammalian Zebrafish and Drosophila models as well as the mammalian rodent systems, comprising rats and mice. The suitability of each animal model, its contribution to the advancement of knowledge in AML pathophysiology and treatment, as well as its advantages and limitations are discussed. Despite some limitations, animal models represent a powerful approach to assess toxicity, and permit the design of new therapeutic strategies.

Emerging agents and regimens for treatment of relapsed and refractory acute myeloid leukemia

Relapsed and refractory acute myeloid leukemia (R/R AML) has complicated pathogenesis. Its treatment is complicated, and the prognosis is poor. So far, there is no consensus on what is the optimal treatment strategy. With the deepening of research, new chemotherapy regimens, new small molecule inhibitors, and immunotherapy have been increasingly applied to clinical trials, providing more possibilities for the treatment of R/R AML. The most effective treatment for patients who achieve complete remission after recurrence is still sequential conditioning therapy followed by allogeneic hematopoietic cell transplantation. Finding the best combination of treatments is still an important goal for the future.

NIPBL: a new player in myeloid cell differentiation

The nucleophosmin 1 gene (NPM1) is the most frequently mutated gene in acute myeloid leukemia. Notably, NPM1 mutations are always accompanied by additional mutations such as those in cohesin genes RAD21, SMC1A, SMC3, and STAG2 but not in the cohesin regulator, nipped B-like (NIPBL). In this work, we analyzed a cohort of adult patients with acute myeloid leukemia and NPM1 mutation and observed a specific reduction in the expression of NIPBL but not in other cohesin genes. In our zebrafish model, overexpression of the mutated form of NPM1 also induced downregulation of nipblb, the zebrafish ortholog of human NIPBL To investigate the hematopoietic phenotype and the interaction between mutated NPM1 and nipblb, we generated a zebrafish model with nipblb downregulation which showed an increased number of myeloid progenitors. This phenotype was due to hyper-activation of the canonical Wnt pathway: myeloid cells blocked in an undifferentiated state could be rescued when the Wnt pathway was inhibited by dkk1b mRNA injection or indomethacin administration. Our results reveal, for the first time, a role for NIPBL during zebrafish hematopoiesis and suggest that an interplay between NIPBL/NPM1 may regulate myeloid differentiation in zebrafish and humans through the canonical Wnt pathway and that dysregulation of these interactions may drive leukemic transformation.

Recent Treatment Advances and the Role of Nanotechnology, Combination Products, and Immunotherapy in Changing the Therapeutic Landscape of Acute Myeloid Leukemia

Acute myeloid leukemia (AML) is the most common acute leukemia that is becoming more prevalent particularly in the older (65 years of age or older) population. For decades, "7 + 3" remission induction therapy with cytarabine and an anthracycline, followed by consolidation therapy, has been the standard of care treatment for AML. This stagnancy in AML treatment has resulted in less than ideal treatment outcomes for AML patients, especially for elderly patients and those with unfavourable profiles. Over the past two years, six new therapeutic agents have received regulatory approval, suggesting that a number of obstacles to treating AML have been addressed and the treatment landscape for AML is finally changing. This review outlines the challenges and obstacles in treating AML and highlights the advances in AML treatment made in recent years, including Vyxeos®, midostaurin, gemtuzumab ozogamicin, and venetoclax, with particular emphasis on combination treatment strategies. We also discuss the potential utility of new combination products such as one that we call "EnFlaM", which comprises an encapsulated nanoformulation of flavopiridol and mitoxantrone. Finally, we provide a review on the immunotherapeutic landscape of AML, discussing yet another angle through which novel treatments can be designed to further improve treatment outcomes for AML patients.

Outcome and Prognostic Factors of High-Risk Acute Myeloid Leukemia After Allogeneic Hematopoietic Stem Cell Transplantation

Background

Allogeneic transplantation remains one of the best therapies for high-risk acute myeloid leukemia (HR-AML).

Material/Methods

This study retrospectively analyzed 126 patients with HR-AML after allogeneic hematopoietic stem cell transplantation (allo-HCST).

Results

The disease-free survival (DFS) rates of 1 year and 3 years were 58.83% (95%CI: 50.75–68.20%) and 53.09% (95%CI: 44.59–63.22%) respectively. The cumulative relapse rates of 1 year and 3 years were 21.1% (95%CI: 14.4–28.8%) and 25.9% (95%CI: 18.1–34.5%) respectively. The cumulative incidences of III to IV acute graft-versus-host disease (aGVHD) for 100 days was 8.70% (95%CI: 4.6–14.5%). The cumulative rate of extensive chronic graft-versus-host disease (cGVHD) for 1-year was 4.1% (95%CI: 1.5–8.7%). The cumulative transplantation related mortality rate of 1 year and 3 years were 20.1% (95%CI: 13.6–27.6%) and 21.0% (95%CI: 14.3–28.6%) respectively. Univariate analysis revealed that lower overall survival was correlated with age, bacterial or fungal infection, disease status at transplantation, III–IV aGVHD, post-transplantation lymphoproliferative disorders (PTLD), white blood cell engraftment, and extramedullary involvement (P<0.05). The results of multivariate analysis were that the aforementioned factors were also related to lower overall survival except for PTLD (P<0.05). The results of univariate and multivariate analysis were that extramedullary involvement, III–IV aGVHD, and status pre-transplantation influenced DFS (P<0.05). The risk factors for relapse were status pre-transplantation and extramedullary involvement by univariate and multivariate analysis (P<0.05).

Conclusions

HR-AML has inferior prognosis. Our study indicated the necessity of achieving remission status prior to hematopoietic stem cell transplantation, and administration of preventive treatments on high-risk patients after hematopoietic stem cell transplantation. In addition, adequate prevention and treatment of complications are needed.