Adult acute leukemia

Acute cardiovascular complications of disseminated intravascular coagulation in acute myeloid leukemia

BACKGROUND

Disseminated intravascular coagulation (DIC) is a common complication of all leukemia subtypes, but it is an especially prominent feature of Acute Myeloid Leukemias (AML). DIC complicating AML can lead to a variety of complications, however, its association with acute cardiovascular complications has not been reported before.

METHODS

National Inpatient Sample Database was used to procure individuals with AML, and baseline demographics and comorbidities were collected using ICD-10-DM codes. Patients were stratified into those with and without DIC. Greedy propensity matching using R was performed to match the two cohorts in 1:1 ratio on age, gender, and fifteen other baseline comorbidities. Univariate analysis pre and post-match along with binary logistic regression analysis post-match were used to analyze outcomes.

RESULTS

Out of a total of 37,344 patients with AML, 996 had DIC. DIC patients were younger, predominantly males, and had lower prevalence of baseline cardiovascular comorbidities. DIC patients had statistically significant higher mortality (30.2 % vs 7.8 %), acute myocardial infarction (5.1 % vs 1.8 %), acute pulmonary edema (2.3 % vs 0.7 %), cardiac arrest (6.4 % vs 0.9 %), and acute DVT/PE (6.6 % vs 2.7 %). Logistic regression model after matching showed similar outcomes along with significantly higher rates of acute heart failure in DIC patients.

CONCLUSION

These findings highlight the importance of close cardiovascular monitoring and prompt recognition of complications in AML patients with DIC. The underlying mechanisms involve a complex interplay of procoagulant factors, cytokine release, and endothelial dysfunction. Further studies are needed to develop targeted interventions for prevention and management of these complications.

Leukemia cancer cells and immune cells derived-exosomes: Possible roles in leukemia progression and therapy

Exosomes have a significant impact on tumor survival, proliferation, metastasis, and recurrence. They also open up new therapeutic options and aid in the pathological identification and diagnosis of cancers. Exosomes have been shown in numerous studies to be essential for facilitating cell-to-cell communication. In B-cell hematological malignancies, the proteins and RNAs that are encased by circulating exosomes are thought to represent prospective sources for therapeutic drugs as well as biomarkers for diagnosis and prognosis. Additionally, exosomes can offer a "snapshot" of the tumor and the metastatic environment at any given point in time. In this review study, we concluded that leukemia-derived exosomes could be utilized as prognostic, diagnostic, and therapeutic biomarkers for individuals suffering from leukemia. Moreover, clinical studies have demonstrated that immune cells like dendritic cells create exosomes, which have the ability to activate the immune system against leukemia.

Various types of electrochemical biosensors for leukemia detection and therapeutic approaches

Leukemia often initiates following dysfunctions in hematopoietic stem cells lineages. Various types of leukemia, including acute lymphoblastic leukemia (ALL), chronic myelogenous leukemia (CML), acute promyelocytic leukemia (APL), and human T-cell leukemia/lymphoma virus type 1 (HTLV-1) can thus call for different diagnosis and treatment options. One of the most important subjects in leukemia is the early detection of the disease for effective therapeutic purposes. In this respect, biosensors detecting the molecules of deoxyribonucleic acid (DNA) as analytes are called genosensors or DNA biosensors. Electrochemical sensors, as the most significant approach, also involve reacting of chemical solutions with sensors to generate electrical signals proportional to analyte concentrations. Biosensors can further help detect cancer cells in the early stages of the disease. Moreover, electrochemical biosensors, developed based on various nanomaterials (NMs), can increase sensitivity to the detection of leukemia-related genes, e.g., BCR/ABL as a fusion gene and promyelocytic leukemia/retinoic acid receptor alpha (PML/RARα). Therefore, the present review reflects on previous studies recruiting different NMs for leukemia detection.

Acute Myeloid Leukemia Presenting Less Than 3 Weeks After Living Donor Kidney Transplant: A Case Report

Acute myeloid leukemia (AML) is a rare malignancy with increased incidence in the kidney transplantation (KT) population for which immunosuppression has been implicated as a putative cause. The average time interval from KT to AML development is 5 years. We present the case of a 61-year-old man who was found to have peripheral blood blasts on a postoperative day 20 routine blood draw after an uneventful unrelated living donor kidney transplant. He subsequently had a bone marrow biopsy and next-generation sequencing (NGS)-based molecular testing, which demonstrated AML characterized by SMC1A and TET2 mutations. He received induction chemotherapy followed by hematopoietic cell transplantation (HCT) from the kidney donor, who happened to be matched at one haplotype. At 12 months after his HCT and 15 months after his KT, his AML remained in remission, normal renal function was preserved, no active graft-versus-host disease was present, and immunosuppression was tapering. With full donor-derived hematopoietic chimerism, we expect to be able to discontinue immunosuppression shortly, thereby achieving tolerance. The short time interval between KT and development of AML suggests the malignancy was likely present before KT. Modern NGS-based analysis offers a promising method of identifying transplant candidates with unexplained hematologic abnormalities on pre-KT testing who may benefit from formal hematologic evaluation.

Jiyuan Oridonin A Overcomes Differentiation Blockade in Acute Myeloid Leukemia Cells With MLL Rearrangements via Multiple Signaling Pathways

Differentiation therapy with all-trans-retinoic acid (ATRA) in acute promyelocytic leukemia (APL), a subtype of acute myeloid leukemia (AML), has been extremely successful in inducing clinical remission in APL patients. However, the differentiation therapy of ATRA-based treatment has not been effective in other subtypes of AML. In this study, we evaluated a small molecule of ent-kaurene diterpenoid, Jiyuan oridonin A (JOA), on the differentiation blockade in AML cells with the mixed lineage leukemia (MLL) gene rearrangements (MLLr) in MV4-11, MOLM-13 and THP-1 cells. We found that JOA could significantly inhibit the proliferation of MOLM-13, MV4-11 and THP-1 cells. Moreover, JOA promoted cell differentiation coupled with cell-cycle exit at G0/G1 and inhibited the colony- forming capacity of these cells. We showed that the anti-proliferative effect of JOA attributed to cell differentiation is most likely through the martens tretinoin response up pathway in the MOLM-13 cell line, and the hematopoietic cell lineage pathway by the inhibition of c-KIT expression and cell adhesion pathway in the THP-1 cell line. Our findings suggest that JOA could be a novel therapeutic agent against human MLLr acute myeloid leukemia.

Mangiferin induces immune responses and evaluates the survival rate in WEHI-3 cell generated mouse leukemia in vivo

Mangiferin is a naturally occurring polyphenol, widely distributed in Thymeraceae families, and presents pharmacological activity, including anti-cancer activities in many human cancer cell lines. Mangiferin has also been reported to affect immune responses; however, no available information concerning the effects of mangiferin on immune reactions in leukemia mice in vivo. In the present study, we investigated the effects of mangiferin on leukemia WEHI-3 cell generated leukemia BLAB/c mice. Overall, the experiments were divided into two parts, one part was immune responses experiment and the other was the survival rate experiment. The immune responses and survival rate study, 40 mice for each part, were randomly separated into five groups (N = 8): Group I was normal animals and groups II-V WEHI-3 cell generated leukemia mice. Group II mice were fed normal diet as a positive control; group III, IV, and V mice received mangiferin at 40, 80, and 120 mg/kg, respectively, by intraperitoneal injection every 2 days for 20 days. Leukocytes cell population, macrophage phagocytosis, and NK cell activities were analyzed by flow cytometry. Isolated splenocytes stimulated with lipopolysaccharide (LPS) and concanavalin A (Con A) were used to determine the proliferation of B and T cells, respectively, and subsequently were analyzed by flow cytometry. Results indicated that mangiferin significantly increased body weight, decreased the liver and spleen weights of leukemia mice. Mangiferin also increased CD3 T-cell and CD19 B cell population but decreased Mac-3 macrophage and CD11b monocyte. Furthermore, mangiferin decreased phagocytosis of macrophages from PBMC and peritoneal cavity at 40, 80, and 120 mg/kg treatment. However, it also increased NK cell activity at 40 and 120 mg/kg treatment. There were no effects on T and B cell proliferation at three examined doses. In survival rate studies, mangiferin significantly elevated survival rate at 40 and 120 mg/kg treatment of leukemia mice in vivo.

Histone lysine demethylase KDM5B maintains chronic myeloid leukemia via multiple epigenetic actions

The histone lysine demethylase KDM5 family is implicated in normal development and stem cell maintenance by epigenetic modulation of histone methylation status. Deregulation of the KDM5 family has been reported in various types of cancers, including hematological malignancies. However, their transcriptional regulatory roles in the context of leukemia remain unclear. Here, we find that KDM5B is strongly expressed in normal CD34⁺ hematopoietic stem/progenitor cells and chronic myeloid leukemia (CML) cells. Knockdown of KDM5B in K562 CML cells reduced leukemia colony-forming potential. Transcriptome profiling of KDM5B knockdown K562 cells revealed the deregulation of genes involved in myeloid differentiation and Toll-like receptor signaling. Through the integration of transcriptome and ChIP-seq profiling data, we show that KDM5B is enriched at the binding sites of the GATA and AP-1 transcription factor families, suggesting their collaborations in the regulation of transcription. Even though the binding of KDM5B substantially overlapped with H3K4me1 or H3K4me3 mark at gene promoters, only a small subset of the KDM5B targets showed differential expression in association with the histone demethylation activity. By characterizing the interacting proteins in K562 cells, we discovered that KDM5B recruits protein complexes involved in the mRNA processing machinery, implying an alternative epigenetic action mediated by KDM5B in gene regulation. Our study highlights the oncogenic functions of KDM5B in CML cells and suggests that KDM5B is vital to the transcriptional regulation via multiple epigenetic mechanisms.

A novel thiosemicarbazone as a promising effective and selective compound for acute leukemia

Acute leukemias are a heterogeneous group of aggressive malignant neoplasms associated with severe morbidities due to the nonselectivity of current chemotherapeutic drugs to nonmalignant cells. The investigation of novel natural and synthetic structures that might be used for the development of new drugs with greater efficiency and selectivity to leukemic cells is mandatory. In this context, thiosemicarbazones have been well described in the literature by their several biological properties and their reaction is known as versatile, low-cost, and highly chemoselective. With this perspective, this study aimed to investigate the cytotoxic effect and the main death mechanisms of a novel thiosemicarbazone (LAP17) on acute leukemia cell lines K562 and Jurkat. The results show that the strong cytotoxic effect of LAP17 to leukemic cells is due to apoptosis induction, which resulted in caspase-3 activation and DNA fragmentation. Intrinsic apoptosis seems to be related to the inversion of Bax/Bcl-2 expression, ΔΨm loss, and AIF release, whereas extrinsic apoptosis was initiated by FasR. Gene-expression profiling of HL-60 cells treated with LAP17 by the microarray technique revealed a significant enrichment of gene sets related to cell cycle arrest at G2/M. Accordingly, K562 and Jurkat cells treated with LAP17 revealed a clear arrest at G2/M phase. Taking into consideration that LAP17 was not cytotoxic to nonhematological cells (peripheral blood mononuclear cell and erythrocytes), these results suggest that LAP17 is a promising new compound that might be used as a prototype for the development of new antileukemic agents.

The experience of medical communication in adults with acute leukemia: Impact of age and attachment security

BACKGROUND

Health care providers' (HCPs) communication with cancer patients provides both information and support. Younger patient age and greater difficulty accepting support (attachment security) have been linked to poorer communication experiences with HCPs. The present secondary data analysis examined the impact of age group and attachment security on perceived communication problems with HCPs in adults with acute leukemia (AL).

METHODS

The sample included 95 younger (age < 40 years) and 225 older (age ≥ 40 years) patients with newly diagnosed or recently relapsed AL. We assessed avoidant and anxious attachment security (reluctance to accept support and fear of its unavailability, respectively) with the modified 16-item Experiences in Close Relationships Scale. The impact of age group and attachment security on perceived communication problems, measured with the Cancer Rehabilitation Evaluation System-Medical Interaction Subscale, was assessed based on the presence and extent of communication problems.

RESULTS

Younger patients (OR = 1.79-1.82, P = .030) and those with greater avoidant (OR = 1.44, P = .001) or anxious attachment (OR = 1.38, P = .009) were more likely to report communication problems. A similar relationship was found between age (β's = -.17-.19, P = .015-.025), avoidant (β = .29, P = .013), or anxious attachment (β = .17, P = .031), and the extent of communication problems. A significant age-group × avoidant-attachment interaction (β = -.31, P = .008) suggested that more avoidant attachment was associated with more perceived communication problems in the younger but not in the older group.

CONCLUSIONS

Younger patients with AL, especially those more reluctant to seek or accept support, perceive more communication problems with their HCPs than older patients. Greater attention by HCPs to their communication with younger patients is needed.

Arsenic trioxide and all-trans-retinoic acid selectively exert synergistic cytotoxicity against FLT3-ITD AML cells via co-inhibition of FLT3 signaling pathways

FLT3-ITD mutations occur in approximately 30% of acute myeloid leukemia (AML) and are associated with a poor outcome. Currently available FLT3 inhibitors have in vitro but limited clinical activity in FLT3-ITD AML. Reports have shown that an arsenic trioxide (ATO)/all-trans-retinoic acid (ATRA) combination improves prognosis in acute promyelocytic leukemia, especially with FLT3-ITD, and ATO or ATRA alone enhances apoptosis in FLT3-ITD AML cells treated with FLT3 inhibitors, providing a rationale to investigate the role of ATO/ATRA in FLT3-ITD AML. Here, we demonstrate that an ATO/ATRA combination selectively exerts synergistic cytotoxicity against FLT3-ITD AML cell lines (MV4;11/MOLM-13). The signaling pathways affected by ATO/ATRA include FLT3/STAT5/MYC, FLT3/STAT5/E2F1, FLT3/ERK/ATF5 and FLT3/AKT/ATF5.ATF5 may function as an oncogene in FLT3-ITD AML. Our findings provide experimental evidence that supports further exploration of ATO/ATRA in FLT3-ITD AML in vivo and warrants a clinical evaluation of regimens comprising an ATO/ATRA combination.

Analysis of factors affecting hemorrhagic diathesis and overall survival in patients with acute promyelocytic leukemia

BACKGROUND/AIMS

This study investigated whether patients with acute promyelocytic leukemia (APL) truly fulfill the diagnostic criteria of overt disseminated intravascular coagulation (DIC), as proposed by the International Society on Thrombosis and Haemostasis (ISTH) and the Korean Society on Thrombosis and Hemostasis (KSTH), and analyzed which component of the criteria most contributes to bleeding diathesis.

METHODS

A single-center retrospective analysis was conducted on newly diagnosed APL patients between January 1995 and May 2012.

RESULTS

A total of 46 newly diagnosed APL patients were analyzed. Of these, 27 patients (58.7%) showed initial bleeding. The median number of points per patient fulfilling the diagnostic criteria of overt DIC by the ISTH and the KSTH was 5 (range, 1 to 7) and 3 (range, 1 to 4), respectively. At diagnosis of APL, 22 patients (47.8%) fulfilled the overt DIC diagnostic criteria by either the ISTH or KSTH. In multivariate analysis of the ISTH or KSTH diagnostic criteria for overt DIC, the initial fibrinogen level was the only statistically significant factor associated with initial bleeding (p = 0.035), but it was not associated with overall survival (OS).

CONCLUSIONS

Initial fibrinogen level is associated with initial presentation of bleeding of APL patients, but does not affect OS.

Treatment for disseminated intravascular coagulation in patients with acute and chronic leukemia

BACKGROUND

Disseminated intravascular coagulation (DIC) is an acquired syndrome characterized by systemic intravascular activation of coagulation, leading to deposition of fibrin in the bloodstream. It may occur in patients with acute and chronic leukemia and is particularly associated with acute promyelocytic leukemia (a subtype of acute myeloid leukemia).

OBJECTIVES

To assess the clinical benefits and harms of any pharmacological intervention for treating DIC in patients with acute or chronic leukemia.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (the Cochrane Library 2015, Issue 05), MEDLINE (1946 to 7 May 2015), LILACS (1982 to 7 May 2015) and African Index Medicus (7 May 2015). There was no language restrictions. We sought additional randomized controlled trials (RCTs) from the World Health Organization International Clinical Trials Registry Platform and the reference lists of primary studies identified.

SELECTION CRITERIA

RCTs assessing the clinical benefits and harms of interventions for treating DIC in patients with acute and chronic leukemia.

DATA COLLECTION AND ANALYSIS

Two review authors independently performed trial selection, 'Risk of bias' assessment and data extraction. Primary outcomes were overall mortality, in-hospital mortality from any cause (15-day and 30-day) and adverse events.

MAIN RESULTS

In this Cochrane Review update we did not include any new RCT compared with the first review version. Accordingly, four RCTs (388 participants) met the inclusion criteria. These trials evaluated the human activated protein C, recombinant human soluble thrombomodulin, tranexamic acid and dermatan sulphate. Included trials reported data on mortality and bleeding. The studies were conducted in Japan, Italy and the Netherlands. We classified the included trials as: 1) including patients with or without leukemia which did not report data for the leukemia subgroup (366 participants); and 2) only including patients with leukemia (22 participants). Overall, the risk of bias of the included trials was high, since the trial authors did not provide a detailed description about trial design and execution.According to the GRADE recommendations, we judged the overall quality of the body of evidence for all prefixed outcomes as 'very low', due to methodological limitations and very small sample size.One trial, including 10 participants with leukemia and comparing dermatan sulphate with heparin, reported no deaths during trial treatment.In terms of bleeding data, we were unable to pool results from two studies that were only conducted with leukemia patients due to the inconsistency in the measurement and reporting of this outcome. One trial, including 12 participants with leukemia, found very low quality evidence that tranexamic acid can reduce the cumulative hemorrhagic score in participants compared with those assigned to placebo (P = 0.0015, very low quality evidence). On the contrary, there is no evidence that dermatan sulphate compared with placebo reduces new events of hemorrhagic diathesis (1/5 (20%) versus 2/5 (40%); RR 0.50; 95% CI 0.06 to 3.91; P = 0.51, very low quality evidence).No thromboembolic complications were reported in either trial that included patients with leukemia only (very low quality evidence). The safety profile was inconclusive.The included trials did not assess overall mortality, resolution of respiratory failure, renal failure or shock.

AUTHORS' CONCLUSIONS

Due to a lack of new RCTs, our conclusions in this Cochrane Review update are the same as the previous review version. We included four RCTs which reported mortality and bleeding data. It is not possible to determine whether human activated protein C, recombinant human soluble thrombomodulin, tranexamic acid and dermatan sulphate are effective or harmful for patients presenting with DIC related to acute or chronic leukemia. The quality of the evidence was low to very low. Therefore, prescription of these interventions for treating DIC in patients with acute and chronic leukemia can neither be supported nor rejected, unless new evidence from a large high-quality trial alters this conclusion.

DNMT3A mutation analysis in adult patients with acute lymphoblastic leukemia

DNA methyl-transferase 3A (DNMT3A) mutation has recently been identified as an independent risk factor for patients with acute myeloid leukemia (AML). However, reports are scanty on its rate and subsequent impact on patients with acute lymphoblastic leukemia (ALL), especially in Chinese population. In this study, we investigated the incidence and prognostic implication of DNMT3A mutation in 57 Chinese adult ALL patients. A total of 3 (5.3%) T-ALL cases were found to have the DNMT3A R882H mutation, which was significantly greater than that found in B-ALL subtype (P=0.048). The patients aged between 40 and 60 years old had higher mutation rate than other age groups (P=0.042). Patients with DNMT3A mutation had shorter overall survival (OS) than their wild-type counterparts. Our study demonstrated that Chinese ALL patients might develop DNMT3A mutation, which exerts a negative impact on their prognosis. These findings might help in risk stratification and treatment choice for Chinese ALL patients.

Prognostic factors in canine acute leukaemias: a retrospective study

Canine acute leukaemias (ALs) have a poor prognosis, with reported survival times (ST) of only a few weeks or months. Also, clinical studies assessing prognostic factors are lacking. This study aims to retrospectively assess variables that predict ST in dogs with AL, and to identify correlations between outcome and therapeutic protocols. Diagnosis and sub-classification into AL subtypes was made based on haematological findings, morphological assessment and flow cytometric immunophenotyping. Clinical-pathological features of AL subtypes at presentation concurred with those described in the literature. A normal neutrophil count at presentation significantly prolonged ST (P = 0.027). Additionally, there was a trend for anaemic dogs to have shorter survival compared with those without anaemia, and the incorporation of cytosine in the chemotherapy protocol produced a moderate but not significant increase in median ST for dogs with AL. Further prospective studies with standardized treatments are needed to confirm and improve our results.

CRIF1 interacting with CDK2 regulates bone marrow microenvironment-induced G0/G1 arrest of leukemia cells

Background

To assess the level of CR6-interacting factor 1 (CRIF1), a cell cycle negative regulator, in patients with leukemia and investigate the role of CRIF1 in regulating leukemia cell cycle.

Methods

We compared the CRIF1 level in bone marrow (BM) samples from healthy and acute myeloid leukemia (AML), iron deficiency anemia (IDA) and AML-complete remission (AML-CR) subjects. We also manipulated CRIF1 level in the Jurkat cells using lentivirus-mediated overexpression or siRNA-mediated depletion. Co-culture with the BM stromal cells (BMSCs) was used to induce leukemia cell cycle arrest and mimic the BM microenvironment.

Results

We found significant decreases of CRIF1 mRNA and protein in the AML group. CRIF1 overexpression increased the proportion of Jurkat cells arrested in G0/G1, while depletion of endogenous CRIF1 decreased cell cycle arrest. Depletion of CRIF1 reversed BMSCs induced cell cycle arrest in leukemia cells. Co-immunoprecipitation showed a specific binding of CDK2 to CRIF1 in Jurkat cells during cell cycle arrest. Co-localization of two proteins in both nucleus and cytoplasm was also observed with immunofluorescent staining.

Conclusion

CRIF1 may play a regulatory role in the BM microenvironment-induced leukemia cell cycle arrest possibly through interacting with CDK2 and acting as a cyclin-dependent kinase inhibitor.

Medical emergency team involvement in patients hospitalized with acute myeloid leukemia

Patients with acute myeloid leukemia (AML) are at risk for sudden clinical deterioration. We aimed to describe the incidence of medical emergency team (MET) activation, intensive care unit (ICU) admissions and outcomes for patients with AML. We performed a 5-year retrospective cohort study of patients hospitalized with AML. One hundred and seventy patients were divided into three groups: (1) MET activated (n = 34); (2) MET criteria present but MET not activated (n = 17); and (3) all other patients with AML (n = 119). MET activation incidence was 200 calls/1000 admissions (95% confidence interval [CI], 138-279), compared with a hospital-wide rate of 29.3 calls/1000 admissions (95% CI, 28.2-30.4) (relative risk 6.90; 95% CI, 4.77-9.67, p < 0.0001). Some 77% (n = 26) were triaged to the ICU. Hospital mortality was higher in MET activated and MET fulfilled without activation groups compared with all others (27% vs. 12% vs. 7%, p = 0.007). Changes to goals of care were more common with MET activation. Patients with AML commonly receive MET activation. Approximately one in 10 fulfill MET criteria, however do not receive MET activation.

Detection and clinical significance of gene rearrangements in Chinese patients with adult acute lymphoblastic leukemia

This study aimed to develop a novel multiplex reverse transcription-nested polymerase chain reaction (RT-nPCR) assay to accurately and effectively detect 10 common gene rearrangements in adult acute lymphoblastic leukemia (ALL) and to examine the clinicopathologic characteristics and other genetic aberrations of patients with ALL expressing different fusion genes. Our RT-nPCR assay had a positive detection rate of 35.15% (90/256) for the 10 fusion genes. BCR-ABL1, FUS-ERG, MLL-AF4, ETV6-RUNX1, E2A-PBX1, dupMLL, MLL-AF10, MLL-ENL, SET-NUP214 and SIL-TAL1 were detected in 36 (14.06%), 14 (5.47%), 14 (5.47%), four (1.56%), four (1.56%), five (1.95%), four (1.56%), two (0.78%), two (0.78%) and five patients (1.95%), respectively. The RT-nPCR results were further confirmed by split-out PCR, and cytogenetic and fluorescence in situ hybridization (FISH) analysis revealed corresponding translocations and fusions in 63 and 74 cases, respectively. JAK2 and IKZF1 mutations were commonly detected in patients with BCR-ABL1 ALL, and HOX overexpression was highly correlated with MLL fusions and SET-NUP214. This study demonstrates that RT-nPCR is an effective method for identifying 10 gene rearrangements in adult ALL, and it could potentially be developed for diagnostic use and prognostic studies of ALL.

Overexpression of amyloid precursor protein in acute myeloid leukemia enhances extramedullary infiltration by MMP-2

It is known that leukemia patients with extramedullary infiltration (EMI) have a worse prognosis than patients without it. Recent data indicate that the amyloid precursor protein (APP) is involved in cell adhesion, motility, and proliferation. The expression of APP and its prognostic significance in acute myeloid leukemia (AML) have not been studied. Our study shows that AML/ETO(+) leukemia patients that overexpress APP easily get EMI and that their long-term survival rate is lower than patients without overexpression of APP. In an in vitro study, we knocked down APP in Kasumi-1 cells using small interfering RNA (siRNA). Transwell data show that siRNA/APP substantially impairs cell migration, but it does not inhibit cell proliferation. Furthermore, by quantitative real-time polymerase chain reaction and Western blot, we found that siRNA/APP decreases MMP-2 expression in vitro. Our study provides a novel clue that APP is involved in the extramedullary infiltration of leukemia by MMP-2.