PP2A is a therapeutically targetable driver of cell fate decisions via a c-Myc/p21 axis in human and murine acute myeloid leukemia.

Dysregulated cellular differentiation is a hallmark of acute leukemogenesis. Phosphatases are widely suppressed in cancers but have not been traditionally associated with differentiation. In this study, we found that the silencing of protein phosphatase 2A (PP2A) directly blocks differentiation in acute myeloid leukemia (AML). Gene expression and mass cytometric profiling revealed that PP2A activation modulates cell cycle and transcriptional regulators that program terminal myeloid differentiation. Using a novel pharmacological agent, OSU-2S, in parallel with genetic approaches, we discovered that PP2A enforced c-Myc and p21 dependent terminal differentiation, proliferation arrest, and apoptosis in AML. Finally, we demonstrated that PP2A activation decreased leukemia-initiating stem cells, increased leukemic blast maturation, and improved overall survival in murine Tet2-/-Flt3ITD/WT and human cell-line derived xenograft AML models in vivo. Our findings identify the PP2A/c-Myc/p21 axis as a critical regulator of the differentiation/proliferation switch in AML that can be therapeutically targeted in malignancies with dysregulated maturation fate.

Young patients with myelofibrosis have distinct clinicomolecular features, favorable prognosis, and commonly exhibit inflammatory comorbidities.

Myelofibrosis (MF) is commonly diagnosed in older individuals and has not been extensively studied in young patients. Given the infrequent diagnosis in young patients, analyzing this cohort may identify factors that predict for disease development/progression. We retrospectively analyzed clinical/genomic characteristics, treatments, and outcomes of patients with MF aged 18-50 years (YOUNG) at diagnosis. Sixty-three YOUNG patients were compared to 663 patients diagnosed at 51 or older (OLDER). YOUNG patients were more likely to be female, harbor driving CALR mutations, lack splicing gene mutations, and have low-risk disease by dynamic international prognostic scoring system (DIPSS) at presentation. Thirty-six patients (60%) presented with incidental lab findings and 19 (32%) with symptomatic disease. Median time to first treatment was 9.4 months (mo). Fourteen (22%) YOUNG patients underwent allogeneic hematopoietic stem cell transplant (median 57.4 mo post-diagnosis). Five (8%) developed blast-phase disease (median 99 mo post-diagnosis). Median overall survival (OS) for YOUNG patients was not reached compared to 62.8 mo in OLDER cohort (p < 0.001). The survival advantage for YOUNG patients lost significance when compared to OLDER patients lacking splicing mutations (p = 0.11). Thirty-one (49%) had comorbidities predating MF diagnosis. Presence of a comorbidity correlated with increased disease risk as measured by serial DIPSS (p=0.02). Increased disease risk correlated with decreased OS (p = 0.05). MF is rare in young adults, has distinct clinical/molecular correlates, and a favorable prognosis. The high frequency of inflammatory comorbidities and their correlation with progression of disease risk clinically highlights the role of inflammation in MF pathogenesis.

A cancer disparities curriculum in a hematology/oncology fellowship program.

BACKGROUND: After George Floyd's murder in 2020, the Center for Disease Control and Prevention (CDC) called systemic racism a public health crisis. This health crisis is connected to the already-documented racial and socioeconomic disparities in cancer care. Ensuring hematologists and oncologists are aware of these disparities through their medical education can help to address these disparities. METHODS: The authors implemented a healthcare disparities-focused curriculum in a Hematology/Oncology fellowship program during the 2020-2021 academic year at The Ohio State University Hematology/Oncology Fellowship Program. They implemented a pre- and post- survey to evaluate the efficacy of the program. RESULTS: Fifteen fellows completed the pre-curriculum survey and 14 completed the post-survey. Before the curriculum, 12 fellows (80%) noted a "Fair" or "Good" understanding of healthcare disparities, and 6 (40%) had a "Fair" understanding of disparities in clinical trials and access to novel therapies. Fourteen fellows (93.3%) had not previously participated in a research project focused on identifying or overcoming healthcare disparities. After the curriculum, 12 (85%) fellows strongly agreed or agreed that the information presented in the curriculum was useful for training as a hematologist/oncologist. Twelve fellows (85%) noted "Agree" or "Strongly Agree" that the information presented was relevant to their practice. Eleven fellows (92%) noted that they plan to incorporate healthcare disparities into a future research or clinical project. The majority of fellows, 11 (79%) recommended that the fellowship program continue to have a formal health disparities curriculum in the future. DISCUSSION/CONCLUSION: There is utility in incorporating cancer disparities education into a hematology/oncology academic curriculum. We recommend further analysis of such curricula to improve fellowship education and patient outcomes with these interventions.

Consensus on acute behavioural disturbance in the UK: a multidisciplinary modified Delphi study to determine what it is and how it should be managed.

BACKGROUND: Acute behavioural disturbance (ABD) is a term used in law enforcement and healthcare, but there is a lack of clarity regarding its meaning. Common language should be used across staff groups to support the identification, prioritisation and delivery of care to this group of patients. The terminology currently used is inconsistent and confusing. This study aimed to reach a consensus on the criteria for identification and management of ABD, and to agree when other care pathways or guidelines might be more appropriately used. METHODS: A modified Delphi study with participation from stakeholder organisation representatives was conducted in January-April 2023 online. In round 1, statements were generated by participants in response to broad questions. Participants then rated their level of agreement with statements in subsequent rounds, with statements achieving a consensus removed for inclusion in the final derived consensus statement. Non-consensus statement responses were assessed for stability. RESULTS: Of 430 unique statements presented for rating, 266 achieved a consensus among 30 participants representing eight stakeholder organisations. A derived consensus statement was generated from these statements. The median group response to statements which failed to achieve a consensus was reliable (Krippendorff's alpha=0·67). CONCLUSIONS: There is a consensus across stakeholder organisations that ABD is not a separate entity to agitation, and guidance should instead be altered to address the full range of presentations of agitation. While the features of concern in this severely agitated group of patients can be described, the advice for recognition may vary depending on staff group. Criteria for recognition are provided and potential new terminology is described.

Investigation of USP30 inhibition to enhance Parkin-mediated mitophagy: tools and approaches.

Mitochondrial dysfunction is implicated in Parkinson disease (PD). Mutations in Parkin, an E3 ubiquitin ligase, can cause juvenile-onset Parkinsonism, probably through impairment of mitophagy. Inhibition of the de-ubiquitinating enzyme USP30 may counter this effect to enhance mitophagy. Using different tools and cellular approaches, we wanted to independently confirm this claimed role for USP30. Pharmacological characterisation of additional tool compounds that selectively inhibit USP30 are reported. The consequence of USP30 inhibition by these compounds, siRNA knockdown and overexpression of dominant-negative USP30 on the mitophagy pathway in different disease-relevant cellular models was explored. Knockdown and inhibition of USP30 showed increased p-Ser65-ubiquitin levels and mitophagy in neuronal cell models. Furthermore, patient-derived fibroblasts carrying pathogenic mutations in Parkin showed reduced p-Ser65-ubiquitin levels compared with wild-type cells, levels that could be restored using either USP30 inhibitor or dominant-negative USP30 expression. Our data provide additional support for USP30 inhibition as a regulator of the mitophagy pathway.

Voltage Imaging with a NIR-Absorbing Phosphine Oxide Rhodamine Voltage Reporter.

The development of fluorescent dyes that emit and absorb light at wavelengths greater than 700 nm and that respond to biochemical and biophysical events in living systems remains an outstanding challenge for noninvasive optical imaging. Here, we report the design, synthesis, and application of near-infrared (NIR)-absorbing and -emitting optical voltmeter based on a sulfonated, phosphine-oxide (po) rhodamine for voltage imaging in intact retinas. We find that po-rhodamine based voltage reporters, or poRhoVRs, display NIR excitation and emission profiles at greater than 700 nm, show a range of voltage sensitivities (13 to 43% ΔF/F per 100 mV in HEK cells), and can be combined with existing optical sensors, like Ca2+-sensitive fluorescent proteins (GCaMP), and actuators, like light-activated opsins ChannelRhodopsin-2 (ChR2). Simultaneous voltage and Ca2+ imaging reveals differences in activity dynamics in rat hippocampal neurons, and pairing poRhoVR with blue-light based ChR2 affords all-optical electrophysiology. In ex vivo retinas isolated from a mouse model of retinal degeneration, poRhoVR, together with GCaMP-based Ca2+ imaging and traditional multielectrode array (MEA) recording, can provide a comprehensive physiological activity profile of neuronal activity, revealing differences in voltage and Ca2+ dynamics within hyperactive networks of the mouse retina. Taken together, these experiments establish that poRhoVR will open new horizons in optical interrogation of cellular and neuronal physiology in intact systems.

Overscreening and Underscreening in Solid-Electrolyte Grain Boundary Space-Charge Layers.

Polycrystalline solids can exhibit material properties that differ significantly from those of equivalent single-crystal samples, in part, because of a spontaneous redistribution of mobile point defects into so-called space-charge regions adjacent to grain boundaries. The general analytical form of these space-charge regions is known only in the dilute limit, where defect-defect correlations can be neglected. Using kinetic Monte Carlo simulations of a three-dimensional Coulomb lattice gas, we show that grain boundary space-charge regions in nondilute solid electrolytes exhibit overscreening-damped oscillatory space-charge profiles-and underscreening-decay lengths that are longer than the corresponding Debye length and that increase with increasing defect-defect interaction strength. Overscreening and underscreening are known phenomena in concentrated liquid electrolytes, and the observation of functionally analogous behavior in solid electrolyte space-charge regions suggests that the same underlying physics drives behavior in both classes of systems. We therefore expect theoretical approaches developed to study nondilute liquid electrolytes to be equally applicable to future studies of solid electrolytes.

Preclinical activity and a pilot phase I study of pacritinib, an oral JAK2/FLT3 inhibitor, and chemotherapy in FLT3-ITD-positive AML.

Activating FLT3 internal tandem duplication (FLT3-ITD) mutations in acute myeloid leukemia (AML) associate with inferior outcomes. We determined that pacritinib, a JAK2/FLT3 inhibitor, has in vitro activity against FLT3-ITD and tyrosine kinase domain (TKD) mutations. Therefore, we conducted a phase I study of pacritinib in combination with chemotherapy in AML patients with FLT3 mutations to determine the pharmacokinetics and preliminary toxicity and clinical activity. Pacritinib was administered at a dose of 100 mg or 200 mg twice daily following a 3 + 3 dose-escalation in combination with cytarabine and daunorubicin (cohort A) or with decitabine induction (cohort B). A total of thirteen patients were enrolled (five in cohort A; eight in cohort B). Dose limiting toxicities include hemolytic anemia and grade 3 QTc prolongation in two patients who received 100 mg. Complete remission was achieved in two patients in cohort A, one of whom had a minor D835Y clone at baseline. One patient in cohort B achieved morphologic leukemia free state. Seven patients (two in cohort A; five in cohort B) had stable disease. In conclusion, pacritinib, an inhibitor of FLT3-ITD and resistant-conferring TKD mutations, was well tolerated and demonstrated preliminary anti-leukemic activity in combination with chemotherapy in patients with FLT3 mutations.

Molecular Complete Remission Following Ivosidenib in a Patient With an Acute Undifferentiated Leukemia.

Acute undifferentiated leukemia (AUL) is a subtype of acute leukemias of ambiguous lineage. There is no standard treatment approach for AUL, although acute lymphoblastic leukemia-like regimens for induction therapy have been used. Additional data suggest that AUL may be better treated as acute myeloid leukemia (AML), given their similarities in genetic, cytogenetic, and gene expression patterns. Somatic mutations of IDH1 are found in 7% to 14% of patients with AML; however, the patient in this study was the first patient with IDH1-mutated AUL treated with ivosidenib. In this case, a woman aged 39 years was found to have anemia and thrombocytopenia after presenting to her primary care physician with fatigue, weight loss, and persistent infections. During further workup of the cytopenia, she was diagnosed with AUL and received 7+3 (daunorubicin, 60 mg/m2/d intravenously on days 1-3, and cytarabine, 100 mg/m2 24-hour continuous intravenous infusion on days 1-7) due to the presence of the IDH1 mutation. Bone marrow biopsy performed on day 14 of 7+3 showed persistent disease, and ivosidenib was initiated due to severe HLA alloimmunization (panel-reactive antibody, 100%) and significant bleeding complications. The patient achieved a complete morphologic and molecular remission on ivosidenib monotherapy despite critical bleeding complications during induction. Targeted therapy using ivosidenib may represent an encouraging therapeutic option in patients with AUL and IDH1 mutations. Additional evaluation of ivosidenib in this subgroup of patients with AUL is needed.

A phase I study of lenalidomide plus chemotherapy with idarubicin and cytarabine in patients with relapsed or refractory acute myeloid leukemia and high-risk myelodysplastic syndrome.

Patients with relapsed/refractory (R/R) acute myeloid leukemia (AML) have poor outcomes and hematopoietic cell transplantation (HCT) is the only curative treatment. New targeted therapies improved survival in select patients with specific mutations, however management of patients without these molecular alterations is an unmet need. We conducted a phase one study of lenalidomide in combination with cytarabine/idarubicin salvage chemotherapy in patients with R/R AML and high-risk myelodysplastic syndromes. A total of 33 patients were enrolled in the study (30 AML, 3 MDS), and treated at three dose levels with 3 + 3 design. Dose-limiting toxicity (DLT) was seen in eight patients, including four hematologic DLTs. The most commonly observed non-hematologic serious adverse events were febrile neutropenia, rash, sepsis and renal injury. Dose level -1, consisting of 25 mg/d lenalidomide D1-21, 1 g/m2 cytarabine D5-8, and 8 mg/m2 idarubicin D5-7 was determined to be the maximum tolerated dose. Note, 15/33 (45%) of patients were able to receive pre-planned 21 days of lenalidomide. Overall, 18 patients achieved complete remission (CR) (n = 14) or CR with incomplete count recovery (CRi) (n = 4) with total CR/CRi rate of 56%. The 1-year and 2-year overall survival (OS) were 24% and 10%, respectively. Among responders, 10/18 underwent allogeneic HCT and had a 1-year OS of 40%. There was no molecular pattern associated with response. These data demonstrate that the combination had clinical activity in R/R AML. This regimen should be further investigated for patients who relapsed after HCT, and as a bridge therapy to HCT. (ClinicalTrials.gov identifier: NCT01132586).

Distance-dependent gradient in NMDAR-driven spine calcium signals along tapering dendrites.

Neurons receive a multitude of synaptic inputs along their dendritic arbor, but how this highly heterogeneous population of synaptic compartments is spatially organized remains unclear. By measuring N-methyl-d-aspartic acid receptor (NMDAR)-driven calcium responses in single spines, we provide a spatial map of synaptic calcium signals along dendritic arbors of hippocampal neurons and relate this to measures of synapse structure. We find that quantal NMDAR calcium signals increase in amplitude as they approach a thinning dendritic tip end. Based on a compartmental model of spine calcium dynamics, we propose that this biased distribution in calcium signals is governed by a gradual, distance-dependent decline in spine size, which we visualized using serial block-face scanning electron microscopy. Our data describe a cell-autonomous feature of principal neurons, where tapering dendrites show an inverse distribution of spine size and NMDAR-driven calcium signals along dendritic trees, with important implications for synaptic plasticity rules and spine function.

Simulating morphologies of organic semiconductors by exploiting low-frequency vibrational modes.

Generating morphologies of amorphous organic materials represents a significant computational challenge and severely limits the size of systems that can be studied. Furthermore, the dynamical evolution of a film at high density occurs on time scales impractical to simulate dynamically, limiting the number of independent states that can be generated. This is a problem in glassy systems as well as protein and polymeric systems. To overcome this problem, we identify rigid sections in molecules and construct an elastic network between them. Using normal mode analysis, we calculate the lowest frequency eigenmodes for the network and displace rigid sections along the low-frequency modes. The system undergoes fast structural relaxation, which allows us to generate many structurally independent approximations to a final atomistic morphology rapidly without force-field parameterization. Using these states as high-density starting configurations, we find equilibrium structures through short molecular dynamics simulations that show close agreement with other atomistic molecular dynamics studies. This method provides a convenient alternative for simulating morphologies of large molecular systems without access to high-performance computing facilities.

The interleukin-3 receptor CD123 targeted SL-401 mediates potent cytotoxic activity against CD34+CD123+ cells from acute myeloid leukemia/myelodysplastic syndrome patients and healthy donors.

Diseases with clonal hematopoiesis such as myelodysplastic syndrome and acute myeloid leukemia have high rates of relapse. Only a small subset of acute myeloid leukemia patients are cured with chemotherapy alone. Relapse in these diseases occurs at least in part due to the failure to eradicate leukemic stem cells or hematopoietic stem cells in myelodysplastic syndrome. CD123, the alpha chain of the interleukin-3 receptor heterodimer, is expressed on the majority of leukemic stem cells and myelodysplastic syndrome hematopoietic stem cells and in 80% of acute myeloid leukemia. Here, we report indiscriminate killing of CD123+ normal and acute myeloid leukemia / myelodysplastic syndrome cells by SL-401, a diphtheria toxin interleukin-3 fusion protein. SL-401 induced cytotoxicity of CD123+ primary cells/blasts from acute myeloid leukemia and myelodysplastic syndrome patients but not CD123- lymphoid cells. Importantly, SL-401 was highly active even in cells expressing low levels of CD123, with minimal effect on modulation of the CD123 target in acute myeloid leukemia. SL-401 significantly prolonged survival of leukemic mice in acute myeloid leukemia patient-derived xenograft mouse models. In addition to primary samples, studies on normal cord blood and healthy marrow show that SL-401 has activity against normal hematopoietic progenitors. These findings indicate potential use of SL-401 as a "bridge-to-transplant" before allogeneic hematopoietic cell transplantation in acute myeloid leukemia / myelodysplastic syndrome patients.

A novel regimen for relapsed/refractory adult acute myeloid leukemia using a KMT2A partial tandem duplication targeted therapy: results of phase 1 study NCI 8485.

KMT2A partial tandem duplication occurs in approximately 5-10% of patients with acute myeloid leukemia and is associated with adverse prognosis. KMT2A wild type is epigenetically silenced in KMT2A partial tandem duplication; re-expression can be induced with DNA methyltransferase and/or histone deacetylase inhibitors in vitro, sensitizing myeloid blasts to chemotherapy. We hypothesized that epigenetic silencing of KMT2A wildtype contributes to KMT2A partial tandem duplication-associated leukemogenesis and pharmacologic re-expression activates apoptotic mechanisms important for chemoresponse. We developed a regimen for this unique molecular subset, but due to relatively low frequency of KMT2A partial tandem duplication, this dose finding study was conducted in relapsed/refractory disease regardless of molecular subtype. Seventeen adults (< age 60) with relapsed/refractory acute myeloid leukemia were treated on study. Patients received decitabine 20 milligrams/meter2 daily on days 1-10 and vorinostat 400 milligrams daily on days 5-10. Cytarabine was dose-escalated from 1.5 grams/meter2 every 12 hours to 3 grams/meter2 every 12 hours on days 12, 14 and 16. Two patients experienced dose limiting toxicities at dose level 1 due to prolonged myelosuppression. However, as both patients achieved complete remission after Day 42, the protocol was amended to adjust the definition of hematologic dose limiting toxicity. No further dose limiting toxicities were found. Six of 17 patients achieved complete remission including 2 of 4 patients with KMT2A partial tandem duplication. Combination therapy with decitabine, vorinostat and cytarabine was tolerated in younger relapsed/refractory acute myeloid leukemia and should be explored further focusing on the KMT2A partial tandem duplication subset. (clinicaltrials.gov identifier 01130506).

A comparison of toxicities in acute myeloid leukemia patients with and without renal impairment treated with decitabine.

Purpose There are limited data regarding the clinical use of decitabine for the treatment of acute myeloid leukemia in patients with a serum creatinine of 2 mg/dL or greater. Methods We retrospectively evaluated 111 patients with acute myeloid leukemia who had been treated with decitabine and compared the development of toxicities during cycle 1 in those with normal renal function (creatinine clearance greater than or equal to 60 mL/min) to those with renal dysfunction (creatinine clearance less than 60 mL/min). Results Notable differences in the incidence of grade ≥3 cardiotoxicity (33% of renal dysfunction patients vs. 16% of normal renal function patients, p = 0.042) and respiratory toxicity (40% of renal dysfunction patients vs. 14% of normal renal function patients, p = 0.0037) were observed. The majority of heart failure, myocardial infarction, and atrial fibrillation cases occurred in the renal dysfunction group. The odds of developing grade ≥3 cardiotoxicity did not differ significantly between patients with and without baseline cardiac comorbidities (OR 1.43, p = 0.43). Conclusions This study noted a higher incidence of grade ≥3 cardiac and respiratory toxicities in decitabine-treated acute myeloid leukemia patients with renal dysfunction compared to normal renal function. This may prompt closer monitoring, regardless of baseline cardiac comorbidities. Further evaluation of decitabine in patients with renal dysfunction is needed.

Decitabine priming enhances the antileukemic effects of exportin 1 (XPO1) selective inhibitor selinexor in acute myeloid leukemia.

The prognosis of acute myeloid leukemia (AML) is poor, highlighting the need for novel treatments. Hypomethylating agents, including decitabine are used to treat elderly AML patients with relative success. Targeting nuclear export receptor (exportin 1 [XPO1]) is a novel approach to restore tumor suppressor (TS) function in AML. Here, we show that sequential treatment of AML blasts with decitabine followed by selinexor (XPO1 inhibitor) enhances the antileukemic effects of selinexor. These effects could be mediated by the re-expression of a subset of TSs (CDKN1A and FOXO3A) that are epigenetically silenced via DNA methylation, and cytoplasmic-nuclear trafficking is regulated by XPO1. We observed a significant upregulation of CDKN1A and FOXO3A in decitabine- versus control-treated cells. Sequential treatment of decitabine followed by selinexor in an MV4-11 xenograft model significantly improved survival compared with selinexor alone. On the basis of these preclinical results, a phase 1 clinical trial of decitabine followed by selinexor in elderly patients with AML has been initiated.

Myelodysplastic Syndromes, Version 2.2017, NCCN Clinical Practice Guidelines in Oncology.

The myelodysplastic syndromes (MDS) comprise a heterogenous group of myeloid disorders with a highly variable disease course. Diagnostic criteria to better stratify patients with MDS continue to evolve, based on morphology, cytogenetics, and the presence of cytopenias. More accurate classification of patients will allow for better treatment guidance. Treatment encompasses supportive care, treatment of anemia, low-intensity therapy, and high-intensity therapy. This portion of the guidelines focuses on diagnostic classification, molecular abnormalities, therapeutic options, and recommended treatment approaches.