Self-Stimulated Photodynamic Nanoreactor in Combination with CXCR4 Antagonists for Antileukemia Therapy.

The treatment of acute myeloid leukemia (AML) remains unsatisfactory, owing to the absence of efficacious therapy regimens over decades. However, advances in molecular biology, including inhibiting the CXCR4/CXCL12 biological axis, have introduced novel therapeutic options for AML. Additionally, self-stimulated phototherapy can solve the poor light penetration from external sources, and it will overcome the limitation that traditional phototherapy cannot be applied to the treatment of AML. Herein, we designed and manufactured a self-stimulated photodynamic nanoreactor to enhance antileukemia efficacy and suppress leukemia recurrence and metastasis in AML mouse models. To fulfill our design, we utilized the CXCR4/CXCL12 biological axis and biomimetic cell membranes in conjunction with self-stimulated phototherapy. This nanoreactor possesses the capability to migrate into the bone marrow cavity, inhibit AML cells from infiltrating into the visceral organ, significantly enhance the antileukemia effect, and prolong the survival time of leukemic mice. Therefore, this nanoreactor has significant potential for achieving high success rates and low recurrence rates in leukemia treatment.

Ferritin-mediated mitochondrial iron homeostasis is essential for the survival of hematopoietic stem cells and leukemic stem cells.

Iron metabolism plays a crucial role in cell viability, but its relationship with adult stem cells and cancer stem cells is not fully understood. The ferritin complex, responsible for intracellular iron storage, is important in this process. We report that conditional deletion of ferritin heavy chain 1 (Fth1) in the hematopoietic system reduced the number and repopulation capacity of hematopoietic stem cells (HSCs). These effects were associated with a decrease in cellular iron level, leading to impaired mitochondrial function and the initiation of apoptosis. Iron supplementation, antioxidant, and apoptosis inhibitors reversed the reduced cell viability of Fth1-deleted hematopoietic stem and progenitor cells (HSPCs). Importantly, leukemic stem cells (LSCs) derived from MLL-AF9-induced acute myeloid leukemia (AML) mice exhibited reduced Fth1 expression, rendering them more susceptible to apoptosis induced by the iron chelation compared to normal HSPCs. Modulating FTH1 expression using mono-methyl fumarate increased LSCs resistance to iron chelator-induced apoptosis. Additionally, iron supplementation, antioxidant, and apoptosis inhibitors protected LSCs from iron chelator-induced cell death. Fth1 deletion also extended the survival of AML mice. These findings unveil a novel mechanism by which ferritin-mediated iron homeostasis regulates the survival of both HSCs and LSCs, suggesting potential therapeutic strategies for blood cancer with iron dysregulation.

Vemurafenib induces senescence in acute myeloid leukemia and myelodysplastic syndrome by activating the HIPPO signaling pathway: implications for potential targeted therapy.

BACKGROUND: The outcome of Acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS) remain dismal despite the development of treatment. Targeted therapy is gaining more and more attention in improving prognosis. METHODS: Expression of BRAF was analyzed by RT-qPCR in AML and MDS patients. Cells viability treated by drugs was measured by CCK-8 assay. Network pharmacology and RNA-sequence were used to analyze the mechanism of drugs and verified in vitro and xenograft tumor model. RESULTS: Here we showed that BRAF was overexpressed in AML and MDS patients, and correlated with poor prognosis. The BRAF inhibitor-Vemurafenib (VEM) could significantly induce senescence, proliferation inhibition and apoptosis in AML cells, which can be enhanced by Bortezomib (BOR). This inhibitory effect was also verified in CD34 + cells derived from AML patients. Mechanistically, we showed that VEM combined with BOR could turn on HIPPO signaling pathway, thereby inducing cellular senescence in AML cells and xenograft mouse. CONCLUSIONS: Taken together, our findings demonstrate a significant upregulation of BRAF expression in AML and MDS patients, which is associated with unfavorable clinical outcomes. We also discovered that the BRAF inhibitor Vemurafenib induces cellular senescence through activation of the HIPPO signaling pathway. Analysis of BRAF expression holds promise as a prognostic indicator and potential therapeutic target for individuals with AML and MDS.

Water extract of earthworms mitigates mouse liver fibrosis by potentiating hepatic LKB1/Nrf2 axis to inhibit HSC activation and hepatocyte death.

ETHNOPHARMACOLOGICAL RELEVANCE: When left untreated, liver fibrosis (LF) causes various chronic liver diseases. Earthworms (Pheretima aspergillum) are widely used in traditional medicine because of their capacity to relieve hepatic diseases. AIM OF THE STUDY: This study aimed to explore the anti-LF effects of water extract of earthworms (WEE) and the underlying molecular mechanisms. MATERIALS AND METHODS: A CCl4-induced mouse model of LF was used to study the impact of WEE on LF in vivo. The anti-LF activity of WEE in mice was compared with that of silybin, which can be clinically applied in LF intervention and was used as a positive control. Activation of LX-2 hepatic stellate cells (HSCs) and apoptosis and ferroptosis of AML-12 hepatocytes induced by TGFß1 were used as in vitro models. RESULTS: WEE drastically improved LF in mice. WEE reduced markers of activated HSCs in mice and inhibited TGFß1-induced activation of LX-2 HSCs in vitro. Additionally, WEE suppressed CCl4-induced apoptosis and ferroptosis in mouse hepatocytes. Mechanistically, WEE induced Nrf2 to enter the nuclei of the mouse liver cells, and the hepatic levels of Nrf2-downstream antioxidative factors increased. LKB1/AMPK/GSK3ß is an upstream regulatory cascade of Nrf2. In the LF mouse model, WEE increased hepatic phosphorylated LKB1, AMPK, and GSK3ß levels. Similar results were obtained for the LX-2 cells. In AML-12 hepatocytes and LX-2 HSCs, WEE elevated intracellular Nrf2 levels, promoted its nuclear translocation, and inhibited TGFß1-induced ROS accumulation. Knocking down LKB1 abolished the impact of WEE on the AMPK/GSK3ß/Nrf2 cascade and eliminated its protective effects against TGFß1. CONCLUSIONS: Our findings reveal that WEE improves mouse LF triggered by CCl4 and supports its application as a promising hepatoprotective agent against LF. The potentiation of the hepatic antioxidative AMPK/GSK3ß/Nrf2 cascade by activating LKB1 and the subsequent suppression of HSC activation and hepatocyte apoptosis and ferroptosis are implicated in WEE-mediated alleviation of LF.

Right femoral vein and right dorsal artery thrombosis in childhood acute myeloid leukemia: A case report.

BACKGROUND: It is rare for newly diagnosed (de novo) or newly treated acute myeloid leukemia (AML) complicated with thrombotic complications, especially combined arterial and venous thrombosis. METHODS: We reported a 13-year-old boy diagnosed with AML and leukocytosis, who developed right femoral vein and right dorsal artery thrombosis during chemotherapy. After treatment with low molecular weight heparin, diosmin, and alprostadil, symptoms were relieved. Unfortunately, the child suffered from coagulopathy afterward, which was unexpectedly caused by vitamin K deficiency. RESULTS: After supplementation with vitamin K and prothrombin complex concentrate, coagulation function recovered. CONCLUSION: For childhood AML patients with high thrombotic risks, close monitoring during anticoagulant treatment was necessary. Concomitantly, we should be alert to past medication history and combined medication use, especially those that may lead to vitamin K deficiency, secondary bleeding, and coagulation disorders. Rational use of antibiotics, anticoagulants, and antitumor drugs must be guaranteed.

Platycodin D induces apoptotic cell death through PI3K/AKT and MAPK/ERK pathways and synergizes with venetoclax in acute myeloid leukemia.

Acute myeloid leukemia (AML) is a highly heterogeneous and rapidly progressive hematopoietic neoplasm characterized by frequent relapses and variable prognoses. The development of new treatment options, therefore, is of crucial importance. Platycodin D (PD) is a triterpenoid saponin, extracted from the roots of the traditional Chinese herbal medicine Platycodon grandiflorum (Jacq.) A. DC., which has been reported to exhibit therapeutic potential against a broad range of cancers. Although the effects of PD on AML remain unclear, in the present study, we observed a concentration-dependent reduction in the viability of multiple human AML cell lines in response to treatment with PD. In addition to triggering mitochondria-dependent apoptosis via the upregulation of BAK and BIM, treatment with PD also induced cell cycle arrest at the G0/G1 phase. Western blot analyses revealed marked suppression of the phosphorylation of protein kinase B (AKT), glycogen synthase kinase-3ß, ribosomal protein S6, and extracellular signal-regulated kinase (ERK) by PD, in turn implying the participation of the phosphoinositide 3-kinase (PI3K)/AKT and mitogen-activated protein kinase (MAPK)/ERK pathways. Pre-incubation with LY294002, MK2206, AR-A014418, or U0126 was consistently found to significantly aggravate PD-induced inhibition of viability. Additionally, PD combined with the B-cell lymphoma 2 (BCL2) inhibitor venetoclax elicited synergistically enhanced cytotoxic effects. The anti-leukemic activity of PD was further validated using primary samples from de novo AML patients. Given the results of the present study, PD may be a potent therapeutic candidate for the treatment of AML.

Recent advance in phytonanomedicine and mineral nanomedicine delivery system of the treatment for acute myeloid leukemia.

Acute myeloid leukemia (AML) is an invasive hematopoietic malignancy caused by excessive proliferation of myeloblasts. Classical chemotherapies and cell transplantation therapies have remarkable efficacy in AML treatment; however, 30-40% of patients relapsed or had refractory disease. The resistance of AML is closely related to its inherent cytogenetics or various gene mutations. Recently, phytonanomedicine are found to be effective against resistant AML cells and have become a research focus for nanotechnology development to improve their properties, such as increasing solubility, improving absorption, enhancing bioavailability, and maintaining sustained release and targeting. These novel phytonanomedicine and mineral nanomedicine, including nanocrystals, nanoemulsion, nanoparticles, nanoliposome, and nanomicelles, offer many advantages, such as flexible dosages or forms, multiple routes of administration, and curative effects. Therefore, we reviewed the application and progress of phytomedicine in AML treatment and discussed the limitations and future prospects. This review may provide a solid reference to guide future research on AML treatment.

Improved efficacy of quizartinib in combination therapy with PI3K inhibition in primary FLT3-ITD AML cells.

Acute myeloid leukemia is a heterogeneous hematopoietic malignancy, characterized by uncontrolled clonal proliferation of abnormal myeloid progenitor cells, with poor outcomes. The internal tandem duplication (ITD) mutation of the Fms-like receptor tyrosine kinase 3 (FLT3) (FLT3-ITD) represents the most common genetic alteration in AML, detected in approximately 30% of AML patients, and is associated with high leukemic burden and poor prognosis. Therefore, this kinase has been regarded as an attractive druggable target for the treatment of FLT3-ITD AML, and selective small molecule inhibitors, such as quizartinib, have been identified and trialled. However, clinical outcomes have been disappointing so far due to poor remission rates, also because of acquired resistance. A strategy to overcome resistance is to combine FLT3 inhibitors with other targeted therapies. In this study, we investigated the preclinical efficacy of the combination of quizartinib with the pan PI3K inhibitor BAY-806946 in FLT3-ITD cell lines and primary cells from AML patients. We show here that BAY-806946 enhanced quizartinib cytotoxicity and, most importantly, that this combination increases the ability of quizartinib to kill CD34+ CD38-leukemia stem cells, whilst sparing normal hematopoietic stem cells. Because constitutively active FLT3 receptor tyrosine kinase is known to boost aberrant PI3K signaling, the increased sensitivity of primary cells to the above combination can be the mechanistic results of the disruption of signaling by vertical inhibition.

miR-338-3p Plays a Significant Role in Casticin-Induced Suppression of Acute Myeloid Leukemia via Targeting PI3K/Akt Pathway.

Objective: Casticin is generally used in traditional herbal medicine for its anti-inflammatory and anticarcinogenic pharmacological properties. Also, microRNAs are indispensable oncogenes or cancer suppressors being dysregulated in various diseases. In this study, we aimed to elucidate the mechanisms underlying effects of casticin on the progression of acute myeloid leukemia (AML). Methods: CCK-8 and flow cytometry were utilized to measure the proliferation and apoptosis of AML cell lines, respectively, after treatment with different concentrations of casticin. The alteration of several microRNA expressions in response to casticin treatment was detected by performing qRT-PCR, and the activity of PI3K/Akt pathways was evaluated through immunoblotting. Afterwards, the potential target gene of miR-338-3p was investigated by dual-luciferase reporter assay. In order to evaluate the role of miR-338-3p in the casticin-induced cellular phenotype changes, AML cells were transfected with miR-338-3p mimics or inhibitor and then subjected to proliferation and apoptosis analysis. Finally, a mouse xenograft model system was employed to investigate the role of casticin in AML progression in vivo. Results: Suppressed cellular proliferation and enhanced apoptosis were observed in HL-60 and THP-1 cells after exposure to casticin, accompanied by remarkable upregulation of the miR-338-3p expression as well as a decline in the phosphorylation of PI3K and Akt proteins. RUNX2 was identified as a direct target molecular of miR-338-3p, which might account for the findings that miR-338-3p knockdown enhanced the PI3K/Akt pathway activity, whereas the miR-338-3p overexpression inactivated this signaling pathway. In addition, the inhibition of the miR-338-3p expression attenuated severe cell apoptosis and suppressions of PI3K/Akt pathway induced by casticin. Furthermore, casticin treatment retarded tumor growth rate in mouse models, whilst elevating miR-338 expression and repressing the activity of PI3K/Akt pathway in vivo. However, miR-338-3p depletion could also abolish the phenotypic alterations caused by casticin treatment. Conclusion: Casticin promotes AML cell apoptosis but inhibits AML cell proliferation in vitro and tumor growth in vivo by upregulating miR-338-3p, which targets RUNX2 and thereafter inactivates PI3K-Akt signaling pathway. Our results provide insights into the mechanisms underlying the action of casticin in the control of AML progression.

An oncogenic enhancer encodes selective selenium dependency in AML.

Deregulation of transcription is a hallmark of acute myeloid leukemia (AML) that drives oncogenic expression programs and presents opportunities for therapeutic targeting. By integrating comprehensive pan-cancer enhancer landscapes with genetic dependency mapping, we find that AML-enriched enhancers encode for more selective tumor dependencies. We hypothesized that this approach could identify actionable dependencies downstream of oncogenic driver events and discovered a MYB-regulated AML-enriched enhancer regulating SEPHS2, a key component of the selenoprotein production pathway. Using a combination of patient samples and mouse models, we show that this enhancer upregulates SEPHS2, promoting selenoprotein production and antioxidant function required for AML survival. SEPHS2 and other selenoprotein pathway genes are required for AML growth in vitro. SEPHS2 knockout and selenium dietary restriction significantly delay leukemogenesis in vivo with little effect on normal hematopoiesis. These data validate the utility of enhancer mapping in target identification and suggest that selenoprotein production is an actionable target in AML.

Metalloproteinase inhibition reduces AML growth, prevents stem cell loss, and improves chemotherapy effectiveness.

Acute myeloid leukemia (AML) is a blood cancer of the myeloid lineage. Its prognosis remains poor, highlighting the need for new therapeutic and precision medicine approaches. AML symptoms often include cytopenias linked to loss of healthy hematopoietic stem and progenitor cells (HSPCs). The mechanisms behind HSPC decline are complex and still poorly understood. Here, intravital microscopy (IVM) of a well-established experimental model of AML allows direct observation of the interactions between healthy and malignant cells in the bone marrow (BM), suggesting that physical dislodgment of healthy cells by AML through damaged vasculature may play an important role. Multiple matrix metalloproteinases (MMPs), known to remodel extracellular matrix, are expressed by AML cells and the BM microenvironment. We reason MMPs could be involved in cell displacement and vascular leakiness; therefore, we evaluate the therapeutic potential of MMP pharmacological inhibition using the broad-spectrum inhibitor prinomastat. IVM analyses of prinomastat-treated mice reveal reduced vascular permeability and healthy cell clusters in circulation and lower AML infiltration, proliferation, and cell migration. Furthermore, treated mice have increased retention of healthy HSPCs in the BM and increased survival following chemotherapy. Analysis of a human AML transcriptomic database reveals widespread MMP deregulation, and human AML cells show susceptibility to MMP inhibition. Overall, our results suggest that MMP inhibition could be a promising complementary therapy to reduce AML growth and limit HSPC loss and BM vascular damage caused by MLL-AF9 and possibly other AML subtypes.

Inhibitors of the Hippo Pathway Kinases STK3/MST2 and STK4/MST1 Have Utility for the Treatment of Acute Myeloid Leukemia.

Serine/threonine-protein kinases 3 and 4 (STK3 and STK4, respectively) are key components of the Hippo signaling pathway, which regulates cell proliferation and death and provides a potential therapeutic target for acute myeloid leukemia (AML). Herein, we report the structure-based design of a series of pyrrolopyrimidine derivatives as STK3 and STK4 inhibitors. In an initial screen, the compounds exhibited low nanomolar potency against both STK3 and STK4. Crystallization of compound 6 with STK4 revealed two-point hinge binding in the ATP-binding pocket. Further characterization and analysis demonstrated that compound 20 (SBP-3264) specifically inhibited the Hippo signaling pathway in cultured mammalian cells and possessed favorable pharmacokinetic and pharmacodynamic properties in mice. We show that genetic knockdown and pharmacological inhibition of STK3 and STK4 suppress the proliferation of AML cells in vitro. Thus, SBP-3264 is a valuable chemical probe for understanding the roles of STK3 and STK4 in AML and is a promising candidate for further advancement as a potential therapy.

Decitabine Enhances Acute Myeloid Leukemia Cell Apoptosis through SH3BGRL Upregulation.

BACKGROUND: SH3-domain-binding glutamic acid-rich protein-like protein (SH3BGRL) is downregulated in acute myeloid leukemia (AML). Clinically, DNA demethylating drug decitabine (DAC) combined with traditional chemotherapies reveals better efficacy on AML patients than the conventional chemotherapies alone. Our previous results revealed that human SH3-domain-binding glutamic acid-rich protein-like protein (SH3BGRL) plays a tumor suppressive role in AML but whether there is a connection between DAC and SH3BGRL expression remains elusive. METHODS: Here, we tentatively treated AML cell lines U937, MV4, and HL-60 with DAC and Western Blots, RT-PCR was used to detect the expression of SH3BGRL. Cell proliferation and apoptosis were determined using Annexin V/7- AAD staining. Real-time RT-PCR and Western blot were used to determine the expression of SH3BGRL mRNA and protein. Methylation-specific PCR was used to quantify the DNA methylation in AML cell lines. RESULTS: DAC had cytotoxicity in HL-60, MV4, and U937. In U937 cell lines, treatment with DAC showed the upregulation of cleaved caspase3, PARP, and SH3BGRL. Upon treatment, up-regulation of SH3BGRL mRNA and protein was dose-dependent and this activity was partially inhibited in endogenous SH3BGRL knockdown cell lines. CONCLUSION: Thus, our results demonstrated a possibly cytotoxic role of DAC on AML cells by upregulation of SH3BGRL expression at epigenetic modulation level and the methylation status in the SH3BGRL promoter region could be a supplemental diagnostic marker to the precise administration of DAC to AML patients.

Valproic acid disables the Nrf2 anti-oxidant response in acute myeloid leukaemia cells enhancing reactive oxygen species-mediated killing.

BACKGROUND: We previously demonstrated the in vitro killing of AML cells by the combination of the lipid-lowering agent bezafibrate (BEZ) and the contraceptive hormone medroxyprogesterone acetate (MPA). A phase II trial demonstrated in vivo safety and efficacy of BEZ and MPA (BaP) in elderly, relapsed/refractory AML and high-risk myelodysplastic syndrome (MDS) patients. However, we observed dose-limiting toxicities in a second trial that attempted to improve outcomes via escalation of BaP doses. Thus we sought to identify a third repurposed drug that potentiates activity of low dose BaP (BaP 0.1 mM). METHODS AND RESULTS: We demonstrate that addition of a commonly used anti-epileptic, valproic acid (VAL) to low dose BaP (BaP 0.1 mM)(VBaP) enhanced killing of AML cell lines/primary AML cells to levels similar to high dose BaP (BaP 0.5 mM). Similarly, addition of VAL to BaP 0.1 mM enhanced reactive oxygen species (ROS), lipid peroxidation and inhibition of de novo fatty acid synthesis. Overexpression of Nrf2 in K562 and KG1a completely inhibited ROS production and rescued cells from VAL/BaP 0.1 mM/VBaP killing. CONCLUSIONS: Given the good safety data of low-dose BaP in elderly/relapsed/refractory AML patients, and that VAL alone is well-tolerated, we propose VBaP as a novel therapeutic combination for AML.

Acute myeloid leukemia with cup-like blasts and FLT3-ITD and NPM1 mutations mimics features of acute promyelocytic leukemia: a case of durable remission after sorafenib and low-dose cytarabine.

Some previous researches raised the possibility of a novel acute myeloid leukemia (AML) entity presenting cup-like cytomorphology with mutations of both FLT3 and NPM1 or one of them. However, the clinical implications of this subtype remain unknown. We describe a 63-year-old patient belonging to this distinct AML subtype, who presented similar features of acute promyelocytic leukemia (APL) including nuclear morphology, negative for CD34 and HLA-DR, and abnormal coagulation. He had no response to both arsenic trioxide and CAG regimen (cytarabine, aclarubicin, and G-CSF). Given that the patient carried the FLT3-ITD mutation, we switched to a pilot treatment of FLT3 inhibitor sorafenib combined with low-dose cytarabine (LDAC). To date, the patient achieved durable complete remission over 58 months. These findings suggest that AML with cup-like blasts and FLT3-ITD and NPM1 mutations mimic APL, and the prognosis of this subtype may be improved by sorafenib combined with LDAC.

Relative effect of Malayer Shahani and Asgari grapes seed extract on inducing apoptosis in human leukemia cells.

BACKGROUND: Previous studies have suggested that consuming fruit and vegetable can lower the risk of several cancers, including breast, colorectal, and lung cancers. AIMS: The present study aims to investigate the in vitro anticancer effects of Shahani and Asgari grape seed extract (GSE) grown in Malayer City of Iran on HL-60 cancer. However, to the best of the author's knowledge, it is the first time in this study that the antiproliferative effect of Shahani and Asgari GSE is compared. MATERIALS AND METHODS: Shahani and Asgari GSE Was extraction white method of Liquid/liquid extraction with ethyl acetate. Then assessing cytotoxic activities of Shahani and Asgari GSE on the HL-60 cells was tested using MTT assay. RESULTS: The results show that compared with the control group, seed extract of both Shahani and Asgari at the various concentrations (25, 50, 100, and 200 µg/ml) had a significantly inhibitory effect on HL-60 cell proliferation that was dose dependent. However, Shahani GSE at different concentrations (50, 100, and 200 µg/ml) indicated a significantly higher inhibitory effect compared to Asgari GSE. In addition, GSE can induce cell cycle arrest at G0/G1 cells. Furthermore, GSE of Asgari and Shahani remarkably increased the induction of HL-60 cell apoptosis depending on its dose. However, at the concentration of 200 µg/ml, GSE induced cell necrosis rather than apoptosis. CONCLUSION: Seed extract of both Shahani and Asgari at the various concentrations had a significantly inhibitory effect on HL-60 cell proliferation that was dose dependent.

Metabolite Profile and In Vitro Beneficial Effects of Black Garlic (Allium sativum L.) Polar Extract.

Over the centuries, humans have traditionally used garlic (Allium sativum L.) as a food ingredient (spice) and remedy for many diseases. To confirm this, many extensive studies recognized the therapeutic effects of garlic bulbs. More recently, black garlic (BG), made by heat-ageing white garlic bulbs, has increased its popularity in cuisine and traditional medicine around the world, but there is still limited information on its composition and potential beneficial effects. In this study, the metabolite profile of methanol extract of BG (BGE) was determined by high-performance liquid chromatography coupled to tandem mass spectrometry in high-resolution mode. Results allowed to establish that BGE major components were sulfur derivatives, saccharides, peptides, organic acids, a phenylpropanoid derivative, saponins, and compounds typical of glycerophospholipid metabolism. Characterization of the BGE action in cancer cells revealed that antioxidant, metabolic, and hepatoprotective effects occur upon treatment as well as induction of maturation of acute myeloid leukemia cells. These results are interesting from the impact point of view of BG consumption as a functional food for potential prevention of metabolic and tumor diseases.

Intracellular ROS profile in hematopoietic progenitors of MDS patients: association with blast count and iron overload.

Objectives: Reactive oxygen species (ROS) are under scrutiny as a participant in the pathophysiology of myelodysplastic syndrome (MDS) and the progression of MDS to acute myeloid leukemia (AML). Measurement of intracellular ROS (iROS) is particularly important since iROS is a direct indicator of cellular health and integrity.Methods: We developed a technique to measure standardize iROS (siROS) level in lymphocytes and bone marrow (BM) CD34+ hematopoietic progenitors using the fluorescent probe dichlorofluorescein (DCF). We then quantified the siROS in 38 consecutive BM specimens from 27 MDS patients over the course of 10 months. Disease outcome of these patients were also assessed.Results: High serum ferritin, high blast count and poor IPSS were associated with inferior survival and AML progression in this cohort. High blast MDS patients had lower siROS in their BM CD34+ cells than those of low blast patients, consistent with increased reliance on glycolysis and enhanced ROS defense in high blast MDS. We also observed narrower siROS distribution in the BM CD34+ cells of high blast patients, suggesting that loss of heterogeneity in ROS content accompanies the clonal evolution of MDS. Furthermore, we observed a strong correlation between CD34+ cells siROS and serum ferritin level in high blast patients. In one case, iron chelation therapy (ICT) resulted in parallel decreases in serum ferritin and CD34+ cells siROS.Conclusion: Our findings established the siROS profile in early hematopoietic cells of MDS patients and its relationship with blast count and iron overload.

Retrospective Analysis of Adult Patients With Relapsed/Refractory Acute Myeloid Leukemia Treated with FLAG at a Comprehensive Cancer Center.

BACKGROUND: FLAG ± Ida (fludarabine, cytarabine, granulocyte colony-stimulating factor, and idarubicin), is a salvage chemotherapy regimen for relapsed or refractory (R/R) acute myeloid leukemia (AML), with complete remission (CR) rates historically ranging from 52% to 63%. We review the outcomes for patients with R/R AML treated with FLAG ± Ida at the University of California Davis Comprehensive Cancer Center. PATIENTS AND METHODS: Adult patients (≥ 18 years) with R/R AML who received FLAG or FLAG + Ida from January 1, 2012 to October 31, 2016 were identified via chart review. Outcomes evaluated were CR, CR with incomplete hematologic recovery (CRi), overall response rate, overall survival (OS), relapse-free survival, and adverse events. RESULTS: Forty-two patients were included. The median age was 52 years (range, 23-73 years), and 57% were male. Sixteen (38.1%) patients had relapsed disease, and 26 (61.9%) had refractory disease. Most (n = 35; 83.3%) patients had European LeukemiaNet intermediate-risk AML. Responses were CR in 20 (47.6%) and CRi in 6 (14.3%). The median OS was 10 months (range, 0.8-51 months), and the median relapse-free survival was 12 months (range, 1-51 months) for responders. The median OS for patients who achieved CR was not reached, and the estimated 48-month survival rate was 56%. The median OS after CRi or no response was 3.47 and 2.17 months, respectively. The median OS was not significantly different when censored for stem cell transplant following chemotherapy, nor with use/deferral of idarubicin. The most common adverse effects were pancytopenia and infection. CONCLUSION: Patient outcomes after treatment with FLAG ± Ida for R/R AML remain similar to prior reports, confirming its role as a salvage regimen for these patients.

microRNA-1246-containing extracellular vesicles from acute myeloid leukemia cells promote the survival of leukemia stem cells via the LRIG1-meditated STAT3 pathway.

Cancer cells-secreted extracellular vesicles (EVs) have emerged as important mediators of intercellular communication in local and distant microenvironment. Our initial GEO database analysis identified the presence of differentially-expressed microRNA-1246 (miR-1246) in acute myeloid leukemia (AML) cell-derived EVs. Consequently, the current study set out to investigate the role of AML-derived EVs-packaged miR-1246 in leukemia stem cells (LSCs) bioactivities. The predicted binding between miR-1246 and LRIG1 was verified using dual luciferase reporter assay. Then, gain- and loss-of-function assays were performed in LSCs, where LSCs were co-cultured with AML cell-derived EVs to characterize the effects of miR-1246-containing EVs, miR-1246, LRIG1 and STAT3 pathway in LSCs. Our findings revealed, in AML cell-derived EVs, miR-1246 was highly-expressed and directly-targeted LRIG1 to activate the STAT3 pathway. MiR-1246 inhibitor or EV-encapsulated miR-1246 inhibitor was found to suppress the viability and colony formation abilities but promoted the apoptosis and differentiation of LSCs through inactivation of STAT3 pathway by up-regulating LRIG1. In addition, the inhibitory effects of AML cell-derived EVs carrying miR-1246 inhibitor on LSCs were substantiated by in vivo experiments. Collectively, our findings reveal that the repression of AML cell-derived EVs containing miR-1246 inhibitor alters the survival of LSCs by inactivating the LRIG1-mediated STAT3 pathway.