Identification of cell surface markers for acute myeloid leukemia prognosis based on multi-model analysis

Given the extremely high inter-patient heterogeneity of acute myeloid leukemia(AML),the identification of biomarkers for prognostic assessment and therapeutic guidance is critical.Cell surface markers(CSMs)have been shown to play an important role in AML leukemogenesis and progression.In the current study,we evaluated the prognostic potential of all human CSMs in 130 AML patients from The Cancer Genome Atlas(TCGA)based on differential gene expression analysis and univariable Cox proportional hazards regression analysis.By using multi-model analysis,including Adaptive LASSO regression,LASSO regression,and Elastic Net,we constructed a 9-CSMs prognostic model for risk stratification of the AML patients.The predictive value of the 9-CSMs risk score was further validated at the transcriptome and proteome levels.Multivariable Cox regression analysis showed that the risk score was an independent prognostic factor for the AML patients.The AML patients with high 9-CSMs risk scores had a shorter overall and event-free survival time than those with low scores.Notably,single-cell RNA-sequencing analysis indicated that patients with high 9-CSMs risk scores exhibited chemotherapy resistance.Furthermore,PI3K inhibitors were identified as potential treatments for these high-risk patients.In conclusion,we constructed a 9-CSMs prognostic model that served as an independent prognostic factor for the survival of AML patients and held the potential for guiding drug therapy.

Circ_0012152 Accelerates Acute Myeloid Leukemia Progression through the miR-652-3p/SOX4 Axis

Objective Acute myeloid leukemia(AML)is an aggressive hematological malignancy characterized by abnormal myeloid blast expansion.Recent studies have demonstrated that circular RNAs play a role in AML pathogenesis.In this study,we aimed to investigate the clinical significance of circ_0012152 in AML and elucidate its underlying molecular mechanism in the pathogenesis of this condition.Methods Circ_0012152 expression was detected by quantitative real-time polymerase chain reaction in samples obtained from 247 patients with AML and 40 healthy controls.A systematic analysis of clinical characteristics and prognostic factors was also conducted.Cell growth was assessed using the Cell Counting Kit-8(CCK-8)assay,and apoptosis and cell cycle progression were evaluated by flow cytometry.Moreover,RNA pull-down was performed to identify target microRNAs,and transcriptome RNA sequencing and bioinformatics analyses were utilized to identify downstream mRNA targets.Results Circ_0012152 was significantly upregulated in samples from patients with AML and served as an independent adverse prognostic factor for overall survival(OS)(hazard ratio:2.357;95%confidence interval 1.258–4.415).The circ_0012152 knockdown reduced cell growth,increased apoptosis,and inhibited cell cycle progression in AML cell lines.RNA pull-down and sequencing identified miR-652-3p as a target microRNA of circ_0012152.Cell growth inhibition by circ_0012152 knockdown was significantly relieved by miR-652-3p inhibitors.We suggested that miR-652-3p targeted SOX4,as the decrease in SOX4 expression resulting from circ_0012152 knockdown was upregulated by miR-652-3p inhibitors in AML cells.Conclusion Circ_0012152 is an independent poor prognostic factor for OS in AML,and it promotes AML cell growth by upregulating SOX4 through miR-652-3p.

Synergistic Effects of Glutamine Deprivation and Metformin in Acute Myeloid Leukemia

Objective The metabolic reprogramming of acute myeloid leukemia(AML)cells is a compensatory adaptation to meet energy requirements for rapid proliferation.This study aimed to examine the synergistic effects of glutamine deprivation and metformin exposure on AML cells.Methods SKM-1 cells(an AML cell line)were subjected to glutamine deprivation and/or treatment with metformin or bis-2-(5-phenylacetamido-1,2,4-thiadiazol-2-yl)ethyl sulfide(BPTES,a glutaminase inhibitor)or cytarabine.Cell viability was detected by Cell Counting Kit-8(CCK-8)assay,and cell apoptosis and reactive oxygen species(ROS)by flow cytometry.Western blotting was conducted to examine the levels of apoptotic proteins,including cleaved caspase-3 and poly(ADP-ribose)polymerase(PARP).Moreover,the human long noncoding RNA(lncRNA)microarray was used to analyze gene expression after glutamine deprivation,and results were confirmed with quantitative RT-PCR(qRT-PCR).The expression of metallothionein 2A(MT2A)was suppressed using siRNA.Cell growth and apoptosis were further detected by CCK-8 assay and flow cytometry,respectively,in cells with MT2A knockdown.Results Glutamine deprivation or treatment with BPTES inhibited cell growth and induced apoptosis in SKM-1 cells.The lncRNA microarray result showed that the expression of MT family genes was significantly upregulated after glutamine deprivation.MT2A knockdown increased apoptosis,while proliferation was not affected in SKM-1 cells.In addition,metformin inhibited cell growth and induced apoptosis in SKM-1 cells.Both glutamine deprivation and metformin enhanced the sensitivity of SKM-1 cells to cytarabine.Furthermore,the combination of glutamine deprivation with metformin exhibited synergistic antileukemia effects on SKM-1 cells.Conclusion Targeting glutamine metabolism in combination with metformin is a promising new therapeutic strategy for AML.

Transforming growth factor-β1 and vascular endothelial growth factor levels in senile acute myeloid leukemia and correlation with prognosis

BACKGROUND Acute myeloid leukemia(AML)is a disease in which immature hematopoietic cells accumulate in the bone marrow and continuously expand,inhibiting hematopoiesis.The treatment and prognosis of this disease have always been unsatisfactory.AIM To investigate the correlation between vascular endothelial growth factor(VEGF)and transforming growth factor-β1(TGFβ1)expression and prognosis in older adults with AML.METHODS This study enrolled 80 patients with AML(AML group),including 36 with complete response(AML-CR),23 with partial response(AML-PR),and 21 with no response(AML-NR).The expression levels of VEGF and TGFβ1 were detected by reverse transcription polymerase chain reaction in bone marrow mononuclear cells isolated from 56 healthy controls.Kaplan-Meier analysis was performed to assess overall survival(OS)and progression-or disease-free survival(DFS).Prognostic risk factors were analyzed using a Cox proportional hazards model.RESULTS The AML group showed a VEGF level of 2.68±0.16.VEGF expression was lower in patients with AML-CR than those with AML-PR or AML-NR(P<0.05).TGFβ1 expression in the AML group was 0.33±0.05.Patients with AML-CR showed a higher TGFβ1 expression than those with AML-PR or AML-NR(P<0.05).VEGF and TGFβ1 expression in patients with AML was significantly correlated with the counts of leukocytes,platelets,hemoglobin,and peripheral blood immature cells(P<0.05);Kaplan-Meier survival analysis revealed that patients with high TGFβ1 expression had better OS and DFS than those with low TGFβ1 expression(P<0.05),whereas patients with low VEGF levels showed better OS and DFS than those with high VEGF levels(P<0.05).VEGF,TGFβ1,and platelet count were identified by the Cox proportional hazards model as independent risk factors for OS(P<0.05),while VEGF,TGFβ1,and white blood cell count were independent risk factors for DFS(P<0.05).CONCLUSION Decreased VEGF expression and increased TGFβ1 expression in patients with AML provide valuable references for determining and individualizing clinical treatment strategies.

Observation on the Clinical Effect of Applying Venetoclax Combined with Demethylation Drug Therapy in Patients with Acute Myeloid Leukemia

Objective: To investigate the therapeutic effect of applying venetoclax combined with demethylating drugs in treating patients with acute myeloid leukemia (AML). Methods: Eighty cases of AML patients treated with venetoclax combined with demethylating drugs in our hospital were selected from March 2021 to March 2024, including 40 cases of primary treatment patients and 40 cases of relapsed and refractory patients. The efficacy and safety of the combined drug therapy was analyzed. Results: The primary treatment group was presented with a complete remission (CR) rate of 40.5%, partial remission (PR) rate of 47.50%, no response (NR) rate of 12.50%, and a remission rate of 87.50%. The relapsed- refractory group was presented with a CR rate of 37.50%, PR rate of 42.50%, NR rate of 17.50%, and a remission rate of 87.50%. There was no statistical significance between the groups (P > 0.05). The hematological adverse reactions of the combined treatment for AML were leukopenia and the non-hematological adverse reactions were mainly infections, with an incidence rate of 87.50%. Conclusion: The efficacy of venetoclax combined with demethylating drugs in AML was remarkable and the treatment regimen can be adjusted according to the treatment-resistant response.

Clinical Effects of Venetoclax in the Treatment of Acute Myeloid Leukemia in the Elderly

Objective: To investigate the clinical efficacy of venetoclax in the treatment of elderly acute myeloid leukemia (AML). Methods: 50 cases of elderly AML patients receiving venetoclax for treatment in the hospital from January 2022 to January 2024 were selected, including 38 cases of patients whose primary treatment was not suitable for intensive chemotherapy and 12 cases of relapsed/refractory AML patients, to observe the therapeutic efficacy and safety of venetoclax. Results: Among the 38 patients whose primary treatment was not suitable for intensive chemotherapy, 5 cases were treated with venetoclax monotherapy, 33 cases were treated with venetoclax + azacitidine, and 25 patients (65.79%) achieved complete remission (CR) with incomplete hematologic recovery (CRi) after 28 days of treatment;10 patients with relapsed/refractory AML were treated with venetoclax + azacitidine, and 2 patients were treated with venetoclax + azacitidine + chemotherapy, and 2 patients achieved optimal therapeutic response after 28 days of treatment and CR/CRi was achieved in 7 patients (58.33%). There were 47 (94.0%) patients with grade 3 or higher granulocytopenia, 46 (92.0%) patients with hemoglobin reduction, and 43 (86.0%) patients with thrombocytopenia, developed after 28 days of treatment. 11 patients developed infections after treatment and there was one case of tumor lysis syndrome. Conclusion: The response rate of venetoclax monotherapy and combination in elderly AML induction therapy is high, and the overall tolerability of elderly patients is good, so it can be popularized and applied.

A model based on eight iron metabolism-related genes accurately predicts acute myeloid leukemia prognosis

Purpose:Iron metabolism maintains the balance between iron absorption and excretion.Abnormal iron metabolism can cause numerous diseases,including tumor.This study determined the iron metabolism-related genes(IMRGs)signature that can predict the prognosis of acute myeloid leukemia(AML).The roles of these genes in the immune microenvironment were also explored.Methods:A total of 514 IMRGs were downloaded from the Molecular Characteristics Database(MSigDB).IMRGs related to AML prognosis were identified using Cox regression and LASSO analyses and were used to construct the risk score model.AML patients were stratified into high-risk groups(cluster 1)and low-risk groups(cluster 2)based on the mean value of the risk score.The accuracy and prognosis prediction potential of the risk-score model was evaluated using Kaplan-Meier and receiver operating characteristics analysis.The stromal score,immune scores,and immune cells infiltrated in AML samples were estimated using CIBERSORT,MCPcountre,and Xcell algorithms.The role of immune checkpoint genes in the AML microenvironment and the prognostic value of the IMRGs were also evaluated.Results:An AML prognosis prediction model was established based on the eight most critical IMRGs.Further analyses revealed that the model could accurately predict AML prognosis.The expression of IMRGs correlated with the infiltration of several immune cells and could influence response to certain chemotherapy drugs and immunotherapy.Conclusion:A model based on IMRGs can accurately predict the overall survival and disease-free survival of AML patients.

Acute pancreatitis as initial presentation of acute myeloid leukemia-M2 subtype:A case report

BACKGROUND Direct infiltration of the pancreas by acute myeloid leukemia(AML)with acute pancreatitis(AP)as an initial symptom is extremely rare.Only once in the literature,the leukemia cells in AML have been implicated as the cause of AP.Pancreatitis caused by a rare predisposing factor is often misdiagnosed as idiopathic pancreatitis or pancreatitis of other common causes.Severe AP(SAP)progresses rapidly with a high fatality rate.Therefore,it is important to identify the predisposing factors in the early stage of SAP,evaluate the condition,determine prognosis,formulate treatment plans,and prevent a recurrence.Here,we describe a case of SAP due to AML.CASE SUMMARY A 61-year-old man presented to the hospital with fever and persistent abdominal pain.Blood analysis presented significantly elevated serum amylase and severe thrombocytopenia.Computed tomography examination of the abdomen revealed peripancreatic inflammatory effusion.The patient had no common etiologies and risk factors for AP,but the concurrent severe thrombocytopenia could not be explained by pancreatitis.Finally,the bone marrow aspirate and biopsy inspection revealed the underlying reason for pancreatitis,AML(M2 type based on the French-American-British classifications system).CONCLUSION Direct infiltration of the pancrease by acute leukemia,particularly AML cells,is an infrequent cause of AP.Therefore,although AP is a rare extramedullary infilt-ration characteristic for AML patients,it should be considered when determining the etiology of AP.

Chidamide,Decitabine,Cytarabine,Aclarubicin,and Granulocyte Colony-stimulating Factor Therapy for Patients with Relapsed/Refractory Acute Myeloid Leukemia:A Retrospective Study from a Single-Center

Objective Preclinical evidence and clinical trials have suggested synergistic effects of epigenetic modifiers in combination with cytotoxic agents for the treatment of leukemia.However,their efficacy in patients with relapsed/refractory acute myeloid leukemia(R/R AML)remains unclear.Methods Clinical data of R/R AML patients who received a CDCAG regimen(chidamide,decitabine,cytarabine,aclarubicin,and granulocyte colony-stimulating factor)from July 1,2018 to October 31,2021 at our center were retrospectively assessed,and the safety and efficacy of the CDCAG regimen were evaluated.Patients were followed up until November 30,2021,with a median follow-up of 21.6 months(95%CI:10.0–33.2 months).Results A total of 67 patients were enrolled.Two patients died within 3 weeks after the initiation,and therefore only 65 patients underwent the assement for clinical response and survival.It was found that 56.9%patients achieved complete remission with a median overall survival(OS)of 9.6 months.The median OS of responders was 25.9 months,while that of non-responders was 5.0 months(P<0.0001).Patients with gene mutations had a superior overall response rate(ORR)(80.4%vs.45.5%,P=0.043)compared to those without gene mutations.The presence of DNA methyltransferase 3 A(DNMT3A),ten-eleven translocation-2(TET2),and isocitrate dehydrogenase 1/2(IDH1/2)mutations did not affect the response rate(88.2%vs.68.9%,P=0.220)and reflected a better OS(not attained vs.9.0 months,P=0.05).The most common non-hematologic adverse events were pulmonary infection(73.1%),followed by febrile neutropenia(23.9%)and sepsis(19.4%).Conclusions The CDCAG regimen was effective and well-tolerated in R/R AML patients,increasing the potential for allogeneic hematopoietic stem cell transplantation.Moreover,patients with DNMT3A,TET2,and IDH1/2 mutations might benefit from this regimen.

Blood typing and transfusion therapy in a patient with A2 subtype acute myeloid leukemia M2:A case report

BACKGROUND Acute myeloid leukemia(AML)is one of the most common types of leukemia in adults.However,AML is relatively rare in the population overall,accounting for only about 1 percent of all cancers.Treatment for AML can be very effective for some patients,yet it leaves others with serious and even life-threatening side effects.Chemotherapy is still the primary treatment for most AML,but over time,leukemia cells become resistant to chemotherapy drugs.In addition,stem cell transplantation,targeted therapy,and immunotherapy are currently available.At the same time,with the progression of the disease,the patient may have corresponding complications,such as coagulation dysfunction,anemia,granulocytopenia,and repeated infection,so transfusion supportive therapy will be involved in the overall treatment regime.To date,few articles have reported on blood transfusion treatment options for patients with ABO subtypes AML-M2.Blood transfusion therapy is an important supportive treatment for AML-M2,and accurate determination of patients'blood type is one of the most important steps in the treatment process.In this study,we explored blood typing and supportive treatment strategies for a patient with A2 subtype AML-M2 to provide the basis for treatment for all patients.CASE SUMMARY In order to determine the blood type of the patient,serological and molecular biological methods were used for reference tests,and the genetic background was studied to determine the patient's final blood type and select the appropriate blood products for infusion treatment.According to the results obtained by serological and molecular biological methods,the blood type of the patient was A2 subtype;the genotype was A02/001;the irregular antibody screening was negative,and anti-A1 was found in the plasma.According to the overall treatment plan,active anti-infection,elevated cells,component blood transfusion support,and other rescue and supportive treatments were given,and the patient successfully passed the stage of myelosuppression after chemotherapy.Re-examination of bone marrow smears showed that AL was in complete remission of bone marrow signs,and minimal residual leukemia lesions suggested no cells with obvious abnormal immunophenotype(residual leukemia cells<10-4).CONCLUSION The infusion of patients with A2 subtype AML-M2 with A irradiated platelets and O washing red blood cells can meet the needs of clinical treatment.

Expression and clinical significance of CANX in acute myeloid leukemia based on TCGA database

Objective:To explore relationships between CANX expression,prognosis and immune infiltration of acute myeloid leukemia(AML)patients.Methods:The TIMER database was used to compare the CANX expression among a variety of TCGA tumor and normal tissue samples.The difference of CANX expression between AML and normal samples was found by R software.The Kaplan-Meier method and Log-Rank test were used to assess the relationship between CANX expression and patient survival.The R software was used to find correlations between CANX expression,clinical characteristics,drug sensitivity,and immune infiltration in AML.Results:The differential expression of CANX in 13 tumor and normal tissue samples were statistically significant(P<0.05).The high CANX expression was associated with a favorable prognosis(P<0.05),which was validated in GSE37642.The expression of CANX was correlated with age,survival status,FAB stage,and karyotype(P<0.05).High CANX expression,low age and favorable karyotype were independent predictors of a favorable prognosis(P<0.05).CANX expression may affect the sensitivity of AML patients to multiple drugs(P<0.05).The expression of CANX was positively correlated with that of M1 macrophages and CD8 T cells.Conclusion:CANX may be used as a novel potential biomarker,and could benefit AML patients by predicting patient prognosis and providing precise treatment indications.

Myeloid sarcoma as the only manifestation in a rare mixed lineage leukemia-fusion-driven acute myeloid leukemia:A case report

BACKGROUND The mixed lineage leukemia(MLL)-eleven-nineteen lysine-rich leukemia(ELL)fusion gene is a rare occurrence among the various MLL fusion genes.We present the first case in which myeloid sarcoma(MS)was the only manifestation of adult MLL-ELL-positive acute myeloid leukemia(AML).CASE SUMMARY We report a case of a 33-year-old male patient who was admitted in June 2022 with a right occipital area mass measuring approximately 7 cm×8 cm.Blood work was normal.The patient underwent right occipital giant subscalp mass excision and incisional flap grafting.Immunohistochemistry was positive for myeloperoxidase,CD43 and CD45 and negative for CD3,CD20,CD34,and CD56.The bone marrow aspirate showed hypercellularity with 20%myeloblasts.Flow cytometry showed that myeloblasts accounted for 27.21%of the nucleated cells,which expressed CD33,CD38,and CD117.The karyotype was 46,XY,t(11,19)(q23;p13.1),-12,+mar/46,XY.Next-generation sequencing showed a fusion of MLL exon 7 to exon 2 of ELL.A diagnosis of MLL-ELL-positive AML(M2 subtype)with subcutaneous MS was made.CONCLUSION MLL-ELL-positive AML with MS is a rare clinical entity.Additional research is needed to elucidate the molecular mechanisms of the pathogenesis of MS.

A Construction of Object Detection Model for Acute Myeloid Leukemia

The evolution of bone marrow morphology is necessary in Acute Mye-loid Leukemia(AML)prediction.It takes an enormous number of times to ana-lyze with the standardization and inter-observer variability.Here,we proposed a novel AML detection model using a Deep Convolutional Neural Network(D-CNN).The proposed Faster R-CNN(Faster Region-Based CNN)models are trained with Morphological Dataset.The proposed Faster R-CNN model is trained using the augmented dataset.For overcoming the Imbalanced Data problem,data augmentation techniques are imposed.The Faster R-CNN performance was com-pared with existing transfer learning techniques.The results show that the Faster R-CNN performance was significant than other techniques.The number of images in each class is different.For example,the Neutrophil(segmented)class consists of 8,486 images,and Lymphocyte(atypical)class consists of eleven images.The dataset is used to train the CNN for single-cell morphology classification.The proposed work implies the high-class performance server called Nvidia Tesla V100 GPU(Graphics processing unit).

Coexistence of diffuse large B-cell lymphoma,acute myeloid leukemia,and untreated lymphoplasmacytic lymphoma/waldenström macroglobulinemia in a same patient:A case report

BACKGROUND The Coexistence of myeloid and lymphoid malignancies is rare.Myeloid leukemia occurs more frequently as a secondary event in patients receiving chemotherapy agents for lymphoid malignancies.Synchronous diagnoses of diffuse large B-cell lymphoma(DLBCL),acute myeloid leukemia(AML),and untreated lymphoplasmacytic lymphoma/Waldenström macroglobulinemia(LPL/WM)in the same patient have not been reported.Here we report one such case.CASE SUMMARY An 89-year-old man had a chest wall mass histopathologically diagnosed as DLBCL.The bone marrow and peripheral blood contained two groups of cells.One group of cells fulfilled the criteria of AML,and the other revealed the features of small B lymphocytic proliferative disorder,which we considered LPL/WM.Multiple chromosomal or genetic changes were detected in bone marrow mononuclear cells,including ATM deletion,CCND1 amplification,mutations of MYD88(L265P)and TP53,WT1 overexpression,and fusion gene of BIRC2-ARAP1,as well as complex chromosomal abnormalities.The patient refused chemotherapy because of old age and died of pneumonia 1 mo after the final diagnosis.CONCLUSION The coexistence of DLBCL,AML,and untreated LPL/WM in the same patient is extremely rare,which probably results from multiple steps of genetic abnormalities.Asymptomatic LPL/WM might have occurred first,then myelodysplastic syndromerelated AML developed,and finally aggressive DLBCL arose.Therefore,medical staff should pay attention to this rare phenomenon to avoid misdiagnoses.

The Applications of Mitoxantrone and Its Liposome in Adult Acute Myeloid Leukemia

Acute myeloid leukemia (AML), a rapidly progressing hematopoietic malignancy, can only be cured hopefully by hematopoietic stem cells transplantation (HSCT). Before HSCT, we usually exert effects by attempting certain regimens to induce these tumor cells to death. Administered in AML patients, the classic “3 + 7” intensive induction regimen including anthracyclines and cytarabine is recommended by guidelines worldwide. However, conventional regimens consist of anthracyclines, a category of drug limited by cumulative, dose-related, progressive myocardial damage and congestive heart failure occurs when its total doses break through the cut-off. Based on this background, mitoxantrone (MIT), an anthraquinone, was developed to a new form to reduce cardiotoxicity. Meanwhile, the nanomedicine, mitoxantrone liposome (Lipo-MIT), was characterized by improved bioavailability and limited toxicity. This drug has great therapeutic potential, but different side effects. We conclude the overall history and development of MIT and Lipo-MIT, which show controversial efficacy of MIT compared to doxorubicin and therapeutic potential of Lipo-MIT. This article reviewed the application of MIT and liposome forms in adult AML patients. .

Prognostic Value of Neutrophil to Lymphocyte Ratio in Acute Myeloid Leukemia

Objective: Acute myeloid leukemia (AML) is a heterogeneous, hematologic malignancy at which short survival may be seen. Our study aims to evaluate the effect of the neutrophil-to-lymphocyte ratio (NLR) on the course of the disease, response to therapy, and overall survival (OS). Materials and Methods: A total of 124 patients followed-up with the diagnosis of AML from 2016 to 2019 were retrospectively examined. Results: 69 of the cases (55.6%) were men and 55 (44.3%) were women. The average age at the time of diagnosis was 53.44 ± 30.3 years old. We determined the NLR as median 0.46 (0.16 - 1.1). In AML, 69 patients were responsive to the induction regimen (57.9%) while 46 patients were unresponsive (37.8%). 5 patients died before completing the regimen. D-dimer was found to be higher and fibrinogen was found to be lower in the responsive group. Lower OS was observed in cases of >60 years of age, male gender, non-APL AML, high NLR, and recurrence at diagnosis. Recurrences were detected in 23 patients (18.5%) and the median time to the recurrence was 416 (236 - 639) days. Fibrinogen level and the bone marrow blast ratio at the time of application were determined to be associated with recurrence. The median follow-up time was 856 (143 - 1276) days. Final condition analysis reveals that 74 patients (59.6%) are alive. Conclusion: We determined in our study that the NLR is effective on survival. Medical literature on this subject is scanty and prospective studies with large patient groups are needed.

Bone marrow niche-mediated survival of leukemia stem cells in acute myeloid leukemia: Yin and Yang

Acute myeloid leukemia （AML） is characterized by the accumulation of circulating immature blasts that exhibit uncontrolled growth, lack the ability to undergo normal differentiation, and have decreased sensitivity to apoptosis. Accumulating evidence shows the bone marrow （BM） niche is critical to the maintenance and retention of hematopoietic stem cells （HSC）, including leukemia stem cells （LSC）, and an increasing number of studies have demonstrated that crosstalk between LSC and the stromal cells associated with this niche greatly influences leukemia initiation, progression, and response to therapy. Undeniably, stromal cells in the BM niche provide a sanctuary in which LSC can acquire a drug-resistant phenotype and thereby evade chemotherapy- induced death. Yin and Yang, the ancient Chinese philosophical concept, vividly portrays the intricate and dynamic interactions between LSC and the BM niche. In fact, LSC-induced microenvironmental reprogramming contributes significantly to leukemogenesis. Thus, identifying the critical signaling pathways involved in these interactions will contribute to target optimization and combinatorial drug treatment strategies to overcome acquired drug resistance and prevent relapse following therapy. In this review, we describe some of the critical signaling pathways mediating BM niche-LSC interaction, including SDFI/CXCL12, Wnt/β-catenin, VCAM/VLA-4/NF-κB, CD44, and hypoxia as a newly-recognized physical determinant of resistance, and outline therapeutic strategies for overcoming these resistance factors.

Resveratrol-downregulated Phosphorylated Liver Kinase B1 Is Involved in Senescence of Acute Myeloid Leukemia Stem Cells

Summary： Senescence is an important obstacle to cancer development. Engaging a senescent response may be an effective way to cure acute myeloid leukemia （AML）. The aim of this study was to examine the effect of resveratrol-downregulated phosphorylated liver kinase B1 （pLKB1） on the senescence of acute myeloid leukemia （AML） stem cells. The protein expressions of pLKB 1 and Sirtuin 1 （SIRT1）, a regulator ofpLKB1, were measured in CD34＋CD38-KGla cells treated with resveratrol （40 μmol/L） or not by Western blotting. Senescence-related factors were examined, including p21 mRNA tested by real-time PCR, cell morphology by senescence-associated β-galactosidase （SA-β-gal） staining, cell pro- liferation by MTT assay and cell cycle by flow cytometry. Besides, apoptosis was flow cytometrically determined. The results showed that pLKB1 was highly expressed in CD34＋CD38- KGla cells, and resveratrol, which could downregulate pLKB1 through activation of SIRT1, induced senescence and apoptosis of CD34＋CD38- KGla cells. It was concluded that resveratrol-downregulated pLKB1 is in- volved in the senescence of AML stem cells.

Update on acute myeloid leukemia stem cells:New discoveries and therapeutic opportunities

The existence of cancer stem cells has been wellestablished in acute myeloid leukemia. Initial proof of the existence of leukemia stem cells(LSCs) was accomplished by functional studies in xenograft models making use of the key features shared with normal hematopoietic stem cells(HSCs) such as the capacity of self-renewal and the ability to initiate and sustain growth of progenitors in vivo. Significant progress has also been made in identifying the phenotype and signaling pathways specific for LSCs. Therapeutically, a multitude of drugs targeting LSCs are in different phases of preclinical and clinical development. This review focuses on recent discoveries which have advanced our understanding of LSC biology and provided rational targets for development of novel therapeutic agents. One of the major challenges is how to target the selfrenewal pathways of LSCs without affecting normal HSCs significantly therefore providing an acceptable therapeutic window. Important issues pertinent to the successful design and conduct of clinical trials evaluating drugs targeting LSCs will be discussed as well.

Dectin-1 rs3901533 and rs7309123 Polymorphisms Increase Susceptibility to Pulmonary Invasive Fungal Disease in Patients with Acute Myeloid Leukemia from a Chinese Han Population

This study aimed to assess whether genetic variants of dendritic cell-associated C-type lectine-1(Dectin-1),Toll-like receptor 2(TLR2),Toll-like receptor 4(TLR4),and myeloid differentiation primary response 88(MyDHH)influence the susceptibility to pulmonary invasive fungal disease(IFD)in patients with acute myeloid leukemia(AML)from a Chinese Han population.Eight single nucleotide polymorphisms(SNPs)of Dectin-1(rs 16910526,rs3901533,and rs7309123),TLR2(rs5743708),TLR4(rs4986790 and rs4986791)and MyD88(rs4988453 and rs4988457)in the genomic DNA of 172 adult AML patients were genotyped.Pulmonary IFD was diagnosed as proven or probable according to the 2008 European Organization for Research and Treatment of Cancer/Invasive Fungal Infections Cooperative Group and the National Institute of Allergy and Infectious Diseases Mycoses Study Group(EORTC/MSG)consensus guidelines.SNPs that were significant in the univariate analysis were further analyzed using the multiple logistic regression analysis to determine their association with the occurrence of pulmonary IFD.The mRNA expression of Dectin-1 was detected according to the genotype by quantitative realtime PCR(qRT-PCR),and the correlation of this expression with the occurrence of pulmonary IFD in AML patients was analyzed.Two Dectin-1 intron SNPs(rs3901533 and rs7309123)were found to be significantly associated with the susceptibility to pulmonary IFD in AML patients in a Chinese Han population.Significant associations were noted between pulmonary IFD and Dectin-1 rs3901533 dominant model(G/T+G/G vs.T/T,OR:2.158;95%Cl:1.109-4.2,P=0.02),Dectin-1 rs3901533 G allele(OR:2.201;95%Cl:1.206-4.019,P=0.01),or Dectin-1 rs7309123 C allele(OR:1.919;95%Cl:1.047-3.518,P=0.03).There were no significant associations between pulmonary IFD and the remaining Dectin-1 SNPs(rs 16910526),TLR2(rs5743708),TLR4(rs4986790 and rs4986791)or MyDHH(rs4988453 and rs4988457).In conclusion,two Dectin-1 SNPs(rs3901533 and rs7309123)are associated with increased susceptibility to pulmonary IFD in AML patients in a Chinese Han population.