Acute myeloid leukemia: focus on novel therapeutic strategies

Patient and Physician Preferences for Acute Myeloid Leukemia Maintenance Treatments Following Hematopoietic Stem Cell Transplantation

Purpose

This study assessed and compared preferences for treatment attributes of maintenance therapies post-hematopoietic stem cell transplantation (HSCT) in patients with acute myeloid leukemia (AML) and in physicians who treat these patients.

Patients and Methods

Patients with AML post HSCT and physicians from the United States, United Kingdom, Canada, and Australia (physicians only) completed a web-based discrete choice experiment (DCE). The DCE used inputs identified via a targeted literature review and qualitative interviews to ascertain relevant treatment attributes and associated levels. Six treatment attributes were selected (chance of 2-year relapse-free survival, quality of life [QoL], risk of serious infections, risk of nausea, chance of achieving transfusion independence, and duration of hospitalization annually), each with three or four levels. The experimental design included 36 choice tasks that presented a pair of hypothetical treatment profiles with varying attribute levels; participants chose a preferred treatment for each choice task. Choice tasks were divided into three blocks of 12 tasks each in the patient survey and 4 blocks of 9 tasks each in the physician survey; survey participants were randomly assigned to one of the blocks. Random parameter logit regression models were used to assess the impact of stated attributes on preferences for maintenance treatment post HSCT.

Results

Surveys from 84 patients and 149 physicians were assessed. For patients, QoL was the most important attribute, followed by duration of hospitalization and chance of 2-year relapse-free survival. For physicians, chance of 2-year relapse-free survival was the most important attribute, followed by QoL and risk of serious infections.

Conclusion

Differences in how patients and physicians valued post-HSCT maintenance treatment attributes were identified. These differences suggest that patient-centered decision-making may help physicians choose maintenance treatments for patients with AML post HSCT that better meet their treatment needs and improve their treatment satisfaction.

Healthcare resource utilization and costs during first salvage therapy for relapsed or refractory acute myeloid leukemia in the United States

Real-world US healthcare resource utilization (HRU) and costs during first salvage therapy for relapsed/refractory (R/R) acute myeloid leukemia (AML) are described using IBM MarketScan® data (1/1/2007-6/30/2020). Treatments included high- (HIC) and low-intensity chemotherapy (LIC) alone, and gilteritinib, other FLT3 tyrosine kinase inhibitors (TKIs), and venetoclax with or without chemotherapy. Patients were diagnosed with R/R AML at ≥18 years of age between 1/1/2017-12/31/2019. Patient monthly all-cause HRU and costs were analyzed using a fixed-effects model. Data from 399 patients were analyzed (HIC, n = 104; LIC, n = 133; gilteritinib, n = 14; other FLT3 TKIs, n = 68; venetoclax, n = 80). Inpatient HRU was generally highest with HIC, whereas outpatient HRU was generally highest with LIC and venetoclax. Total all-cause incremental monthly costs appeared to be highest with HIC ($171,982) and similar for LIC ($60,512), gilteritinib ($47,218), other FLT3 TKIs ($43,218), and venetoclax ($77,566). Results highlight HRU and cost differences for R/R AML during first salvage therapy.

Making Biomarkers Relevant to Healthcare Innovation and Precision Medicine

Translational medicine, the exchange between laboratory (bench) and the clinic (bedside), is decidedly taking on a vital role. Many companies are now focusing on a translational medicinal approach as a therapeutic strategy in decision making upon realizing the expenses of drug attrition in late-stage advancement. In addition, the utility of biomarkers in clinical decision and therapy guidance seeks to improve the patient outcomes and decrease wasteful and harmful treatment. Efficient biomarkers are crucial for the advancement of diagnoses, better molecular targeted therapy, along with therapeutic advantages in a broad spectrum of various diseases. Despite recent advances in the discovery of biomarkers, the advancement route to a clinically validated biomarker remains intensely challenging, and many of the candidate biomarkers do not progress to clinical applications, thereby widening the innovation gap between research and application. The present article will focus on the clinical view of biomarkers in a reverse design, addressing how a biomarker program should appear if it is expected to create an impact on personalized medicine and patient care.

The Global Burden of Leukemia and Its Attributable Factors in 204 Countries and Territories: Findings from the Global Burden of Disease 2019 Study and Projections to 2030

Background. Leukemia is a common malignancy that has four main subtypes and is a threat to human health. Understanding the epidemiological status of leukemia and its four main subtypes globally is important for allocating appropriate resources, guiding clinical practice, and furthering scientific research. Methods. Average annual percentage changes (AAPCs) were calculated to estimate the change trends of age-standardized rates (ASRs) from 1990 to 2019 in 204 countries and territories. The risk factors for leukemia death and disability-adjusted life-year (DALY) were also analyzed. In addition, the future trends in ASRs were projected through 2030. Results. The total number of incident cases, deaths, and DALYs from leukemia in 2019 was 0.64, 0.33, and 11.66 million, respectively. Decreasing trends in age-standardized incidence rate (ASIR), the age-standardized death rate (ASDR), and age-standardized DALY rate were detected on a global level while increasing trends in ASIR were detected in the high-sociodemographic index (SDI) regions. The leukemia burden was heavier in males than in females. By cause, acute myeloid leukemia (AML), chronic myeloid leukemia (CML), and chronic lymphocytic leukemia (CLL) were more likely to impose a burden on the elderly, while acute lymphoblastic leukemia (ALL) showed a greater impact in the younger population. A significant positive correlation was observed between SDI and AAPC in ASIR, while SDI was negatively correlated with AAPCs in both ASDR and age-standardized DALY rate. Smoking remained the most significant risk factor associated with leukemia-related death and DALY, especially in males. Similar deaths and DALYs were caused by smoking and high body mass index (BMI) in females. Future projections through 2030 estimated that ASIR and ASDR will continue to increase, while the DALY rate is predicted to decline. Conclusions. Patterns and trends of leukemia burden are correlated with SDI. The estimated contributions to leukemia deaths indicate that timely measures are needed to reduce smoking and obesity.

RSK Isoforms in Acute Myeloid Leukemia

Ribosomal S6 Kinases (RSKs) are a group of serine/threonine kinases that function downstream of the Ras/Raf/MEK/ERK signaling pathway. Four RSK isoforms are directly activated by ERK1/2 in response to extracellular stimuli including growth factors, hormones, and chemokines. RSKs phosphorylate many cytosolic and nuclear targets resulting in the regulation of diverse cellular processes such as cell proliferation, survival, and motility. In hematological malignancies such as acute myeloid leukemia (AML), RSK isoforms are highly expressed and aberrantly activated resulting in poor outcomes and resistance to chemotherapy. Therefore, understanding RSK function in leukemia could lead to promising therapeutic strategies. This review summarizes the current information on human RSK isoforms and discusses their potential roles in the pathogenesis of AML and mechanism of pharmacological inhibitors.

Inhibition of Exosome Release Sensitizes U937 Cells to PEGylated Liposomal Doxorubicin

Aims

Acute myeloblastic leukemia (AML) is the most common type of acute leukemia in adults. Despite numerous treatment strategies including chemotherapy and radiotherapy, a large number of patients do not respond to treatment and experience relapse. The main problem of these patients is the development of resistance to anti-cancer drugs. Therefore, any endeavor to reduce drug resistance in these patients is of high priority. In general, several mechanisms such as changes in drug metabolic pathways, drug inactivation, drug target alterations and reduced drug accumulation in the cells contribute to drug resistance of cancer cells. In this context, evidence suggests that exosomes could reduce drug resistance by removing drugs from their parent cells. In the present study, we aimed to investigate the effects of exosome release inhibition on the resistance of U937 cells to PEGylated liposomal doxorubicin (PLD).

Main Methods

In order to find a suitable ABCG2 (ATP-binding cassette sub-family G member 2) transporter substrate, virtual screening was performed among a list of drugs used in leukemia and PLD was selected. U937 cells were treated with PLD with/without co-treatment with the exosome release inhibitor, GW4869. Released exosomes within different study groups were isolated and characterized to determine the differences between groups. Doxorubicin presence in the isolated exosomes was also measured by high performance liquid chromatography (HPLC) to confirm drug export through the exosomes. Finally, the effect of exosome inhibition on the cytotoxicity of PLD on U937 cells was determined using different cytotoxicity assays including the standard lactate dehydrogenase (LDH) release assay and the flow cytometric analysis of apoptotic and non-apoptotic cell death.

Key Findings

GW4869 treatment caused a significant decrease in the exosome release of U937 cells compared to the untreated cells, as evidenced by the reduction of the protein content of the isolated exosomes (P<0.05). Co-treatment with GW4869 significantly increased cytotoxic cell death in the groups treated with 0.5 and 1 µM PLD, compared to the same groups without GW4869 co-treatment (P<0.05). Interestingly, co-treatment with GW4896 and 0.5 µM PLD was enough to induce the same cytotoxic effect as that of the sole 1 µM PLD group.

Significance

Our findings showed that U937 cells increase their resistance against the cytotoxic effects of PLD through the exosome-mediated expelling of the drug. Inhibition of exosome release could prevent PLD efflux and consequently increase the vulnerability of the U937 cells to the cytotoxic effects of PLD. Our results along with prior studies indicate that the integration of exosome release inhibitors into the common PLD-containing chemotherapy regimens could significantly lower the required concentrations of the drug and consequently reduce its associated side effects. Further studies are warranted to identify clinically safe inhibitors and investigate their clinical efficacy.

Cost-effectiveness of midostaurin in the treatment of newly diagnosed FLT3-mutated acute myeloid leukemia in France

BACKGROUND

Midostaurin (MIDO) combined with standard chemotherapy was approved by the European Medicines Agency in 2017 for the treatment of adults with newly diagnosed FLT3-mutated acute myeloid leukemia (AML) based on results from the RATIFY trial.

METHODS

A cost-effectiveness model was developed to compare MIDO and standard-of-care (SOC) to SOC alone in France. Per Haute Autorité de Santé (HAS) guidelines, a partitioned survival model with eight health states was used: diagnosis/induction, complete remission, relapse, hematopoietic stem cell transplantation (HSCT), HSCT recovery, post-HSCT recovery (stabilized after HSCT recovery), post-HSCT relapse, and mortality. A lifetime horizon was used beginning at diagnosis with a "cure model,", which assumed natural mortality after trial cut-off. Utility values were obtained from a systematic literature review and included disutilities. Resource utilization was based on HAS clinical guidelines and a survey of French physicians and included drugs and administration, adverse events, routine medical care, HSCT, and end-of-life care costs.

RESULTS

In RATIFY and after extrapolation, MIDO improved survival compared to SOC, translating into MIDO-treated patients gaining 1.12 life years (LYs) and 1.23 quality-adjusted life years (QALYs) versus SOC. The incremental cost-effectiveness ratio (ICER) for MIDO versus SOC was €68,781 per LY and €62,305 per QALY. Sensitivity analyses showed consistency with base case findings.

CONCLUSIONS

MIDO represents a clinically significant advancement in the management of newly diagnosed FLT3-mutated AML. In this analysis, MIDO add-on therapy showed gains in LYs and QALYs versus SOC alone and was found to be a cost-effective option at a €100,000 per QALY threshold for end-of-life treatment.

Bibliometric analysis of studies about acute myeloid leukemia conducted globally from 1999 to 2018

A bibliometric study is performed to analyze publication patterns in a specific research area and to establish a landscape model that can be used to quantitatively weigh publications. This study aimed to investigate AML research networks and to conduct a trend-related keyword analysis. We analyzed 48,202 studies about AML published from 1999 to 2019 in the Web of Science Core Collection. The network analysis was conducted using the R&R studio software. The journal Blood had the highest number of published articles with an h-index of 410. The USA had the highest number of total publications (18,719, 38.3%) and research funded by the government, institutions, and pharmaceutical companies (5,436, 10.8%). The institute with the largest number of publications was the MD Anderson Cancer Center. Kantarjian H, Garcia-Manero G, and Ravandi F were the leading authors of publications about AML. Keyword analysis revealed that FLT 3, micro-RNA, and NK cell topics were the hotspots in the cell and gene area in all publications. The overall AML research landscape is popular in the field of translational research as it can identify molecular, cell, and gene studies conducted by different funding agencies, countries, institutions, and author networks. With active funding and support from the Chinese government, the productivity of scientific research is increasing not only in the AML field but also in the medical/health-related science field.

HMGA2 regulates acute myeloid leukemia progression and sensitivity to daunorubicin via Wnt/β-catenin signaling

Acute myeloid leukemia (AML) is a malignant disease with an increasing prevalence in adults and children. However, valuable molecular diagnostic research is rare. In the present study, plasmids silencing and overexpressing high‑mobility group AT‑hook 2 (HMGA2) were respectively transfected in HL60 and NB4 cells. The effects of HMGA2 on AML cell viability, apoptosis, migration and invasion were determined by preforming MTT, flow cytometry, wound scratch and Transwell assays, respectively. Genes associated with apoptosis and Wnt signaling were evaluated by reverse transcription‑quantitative (RT‑q)‑PCR and western blotting. AML cell sensitivity to daunorubicin (DNR) and the regulatory effects of the Wnt signaling pathway via HMGA2 following treatment with the agonist LiCl or antagonist XAV939 were detected by MTT, RT‑qPCR and western blot analysis. The results revealed that the expression of HMGA2 was elevated more so in HL60, KG1, U937, Kasumi‑1, THP‑1 and K562 cells than in NB4 cells. Silencing HMGA2 suppressed cell viability, migration and invasion, enhanced cell apoptosis and sensitivity to DNR, and almost restored the DNR inhibitory function that was promoted by LiCl treatment. In addition, low expression of HMGA2 attenuated X‑linked inhibitor of apoptosis and Bcl‑2 mRNA and protein levels, and upregulated the expression of Bax and cleaved‑caspase‑3. Furthermore, silencing HMGA2 not only decreased Wnt and non‑phospho‑β‑catenin expressions, but also partially reversed the increased expressions of these proteins induced by LiCl treatment. On the other hand, overexpression of HMGA2 exhibited the opposite results after transfection in NB4 cells. The results of the present study demonstrated that HMGA2 played important roles in driving AML progression and chemosensitivity in HL60 and NB4 cells, potentially by activating the Wnt/β‑catenin signaling pathway. Therefore, it was suggested that HMGA2 may be a promising molecular marker for AML diagnosis.

Expression of antiapoptotic proteins livin and survivin in pediatric AML patients, as prognostic markers

OBJECTIVE

Survivin and livin are highly expressed in various malignancies and their expression levels may be related to unfavorable prognosis. The aim was to investigate the relationships of these two markers with some prognostic factors and with survival of the children with acute myeloid leukemia (AML).

METHODS

Livin and survivin expression was investigated quantitatively by immunohistochemistry staining technique in 43 primary formalin-fixed, paraffin-embedded bone marrow blocks in pediatric age group (<18 years).

RESULTS

Both survivin and livin were expressed in 81.4% of AML patients. Livin expression showed significant positive association with high level of primary WBC (p = .002). Survivin expression showed significant positive correlations with risk of relapse (p ≤ .001) and high level of primary WBC (p = .003). The relationship of overall survival (OS) of the patients with livin and survivin expression, were investigated separately in disease subtypes. Significant association was observed between survivin expression and shorter OS regardless of subtypes including acute promyelocytic (APL) (p = .01) and nonacute promyelocytic leukemia (non-APL) (p = .008). Also, significant association of livin expression with shorter OS was detected, but only in APL subgroup (p = .046). Nevertheless, in Cox regression model after adjusting for disease subtypes, stage and cytogenetics; survivin and livin showed no significant association with OS (p > .05).

CONCLUSION

Livin and survivin showed significant associations with some poor prognostic factors of AML. Although survivin in both subtypes and livin in non APL subtype, showed a significant relationship with shorter OS, none of them was determined as independent prognostic factors. Further studies with larger sample size are suggested.

An open-label, single-dose, phase 1 study of the absorption, metabolism and excretion of quizartinib, a highly selective and potent FLT3 tyrosine kinase inhibitor, in healthy male subjects, for the treatment of acute myeloid leukemia

1. Quizartinib absorption, metabolism and excretion were characterized in six healthy men receiving a single oral dose of 60 mg (≈100 μCi) of [¹⁴C]-quizartinib. Blood, plasma, urine and faeces were collected ≤336 h postdose. 2. Four hours postdose, maximum mean ± SD blood radioactivity concentrations were 296 ± 67.4 ng equivalents/g. A mean ± SD of 1.64 ± 0.482% and 76.3 ± 6.23% of the dose was recovered in urine and faeces, respectively, within 336 h postdose. 3. Radio-detector high-performance liquid chromatography (radio-HPLC) and liquid chromatography-mass spectrometry (LC-MS) showed two main radioactive peaks in plasma, unchanged quizartinib and mono-oxidative metabolite, AC886. Five additional metabolites in plasma were identified by LC-MS, but low levels prevented radio-HPLC detection. Although unchanged quizartinib was the main radioactive component in faeces (mean, 4.0% of administered dose), 15 metabolites representing a mean of 1.0-3.5% of administered dose were found. Quizartinib was predominantly metabolized by phase I biotransformations (oxidation, reduction, dealkylation, deamination, hydrolysis and combinations thereof). 4. This study indicated that quizartinib was rapidly and orally bioavailable, extensively metabolized, with AC886 as the major circulating metabolite, and predominantly eliminated in faeces. Quizartinib was well tolerated in the subjects.

Selective Targeting of RSK Isoforms in Cancer

The p90 ribosomal S6 kinase family (RSK1-4) is a group of highly conserved Ser/Thr kinases that act as downstream effectors of the Ras/Raf/MEK/ERK signaling pathway. The RSKs phosphorylate a range of substrates involved in transcription, translation, cell cycle regulation, and cell survival. Although the RSKs have a high degree of sequence homology, their functional differences in cancer are of great interest. Current RSK inhibitors target more than one RSK isoform, and this may limit their efficacy as anticancer agents. Here, we review the structure and function of the RSK kinases, their role in cancer growth and survival, and their potential as modulators of chemoresistance. In addition, we summarize the development of current RSK inhibitors and their limitations.

A novel approach for the identification of efficient combination therapies in primary human acute myeloid leukemia specimens

Appropriate culture methods for the interrogation of primary leukemic samples were hitherto lacking and current assays for compound screening are not adapted for large-scale investigation of synergistic combinations. In this study, we report a novel approach that efficiently distills synthetic lethal interactions between small molecules active on primary human acute myeloid leukemia (AML) specimens. In single-dose experiments and under culture conditions preserving leukemia stem cell activity, our strategy considerably reduces the number of tests needed for the identification of promising compound combinations. Initially conducted with a selected library of 5000 small molecules and 20 primary AML specimens, it reveals 5 broad classes of sensitized therapeutic target pathways along with their synergistic patient-specific fingerprints. This novel method opens new avenues for the development of AML personalized therapeutics and may be generalized to other tumor types, for which in vitro cancer stem cell cultures have been developed.

All-trans retinoic acid synergizes with topotecan to suppress AML cells via promoting RARα-mediated DNA damage

Background

Chemotherapy is the only therapy option for the majority of AML patients, however, there are several limitations for this treatment. Our aim was to find a new chemotherapy strategy that is more effective and less toxic.

Methods

MTT assays and a xenograft mouse model were employed to evaluate the synergistic activity of all-trans retinoic acid (ATRA) combined with topotecan (TPT). Drug-induced DNA damage and apoptosis were determined by flow cytometry analysis with PI and DAPI staining, the comet assay and Western blots. Short hairpin RNA (shRNA) and a RARα plasmid were used to determine whether RARα expression influenced DNA damage and apoptosis.

Results

We found that ATRA exhibited synergistic activity in combination with Topotecan in AML cells, and the enhanced apoptosis induced by Topotecan plus ATRA resulted from caspase pathway activation. Mechanistically, ATRA dramatically down regulated RARα protein levels and led to more DNA damage and ultimately resulted in the synergism of these two agents. In addition, the increased antitumor efficacy of Topotecan combined with ATRA was further validated in the HL60 xenograft mouse model.

Conclusions

Our data demonstrated, for the first time, that the combination of TPT and ATRA showed potential benefits in AML, providing a novel insight into clinical treatment strategies.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-015-2010-6) contains supplementary material, which is available to authorized users.

Successful management of acute myeloid leukemia transformed from chronic myelomonocytic leukemia in the elderly by a combination regimen of decitabine and cytarabine, aclarubicin and granulocyte colony-stimulating factor: A case report

Despite advances in the treatment of acute myeloid leukemia (AML) in recent years, the outcome of elderly AML patients with antecedent hematological disorders remains unsatisfactory. The present study describes a case of complete remission in an elderly patient with AML transformed from chronic myelomonocytic leukemia (CMML) and the treatment of the case with decitabine in combination with cytarabine, aclarubicin and granulocyte colony-stimulating factor (CAG). A 70-year-old male was admitted with fever, pruritus and weakness that had been apparent for two weeks, and a two-year history of monocytosis (22.5–27.0%). Further examinations revealed a hemoglobin level of 106 g/l, a white blood cell count of 39.52×10⁹/l, a platelet count of 81×10⁹/l, Y chromosome loss and uniparental disomy on chromosomes 4q, 2q and 19p. The patient was diagnosed with AML transformed from CMML, with cytogenetic anomalies. A combination regimen of decitabine and CAG was administered. Subsequent to one cycle, the patient achieved complete remission. The patient was then followed up with three courses of the same regimen and achieved clinical remission, with no evidence of AML relapse. The present study suggests that a combination of low-dose decitabine and CAG may offer a novel and potentially effective treatment regimen for elderly AML patients.

Association of ABCB1 polymorphisms with prognostic outcomes of anthracycline and cytarabine in Chinese patients with acute myeloid leukemia

PURPOSE

To investigate the influence of ABCB1 polymorphisms on prognostic outcomes in Chinese patients with de novo intermediate-risk acute myeloid leukemia (AML) and to examine the gene expression level in relation to the genetic variation.

METHODS

In total, 263 Chinese intermediate-risk AML patients treated with anthracycline and cytarabine were enrolled. G2677T, C1236T, and C3435T of the ABCB1 gene were analyzed by the allele-specific matrix-assisted laser desorption. Expression of ABCB1 messenger RNA (mRNA) was tested in 101 patients of known genotype and haplotype for ABCB1 polymorphisms. Basic clinical characteristics of these patients were collected from medical records.

RESULTS

Survival analysis showed that patients with AML (TTT haplotype) had a longer overall survival (OS) (p < 0.001, 29.2 months, 95 % confidence interval [CI], 26.9-31.5 months) and relapse-free survival (RFS) (p = 0.005, 21.8 months, 95 % CI, 19.5-24.0 months) compared with those without TTT haplotype (21.9 months, 95 % CI, 19.6-24.2 months; 16.5 months, 95 % CI, 14.6-18.5 months). After adjusting for age; gender; leukocyte count; hemoglobin level; platelet levels; French, American, and British classification; lactate dehydrogenase levels; Eastern Cooperative Oncology Group performance status; nucleophosmin gene; and fms-related tyrosine kinase 3 gene, the multivariate survival analysis showed that the TTT haplotype appeared to be a predicting factor for OS (p = 0.001, hazard ratio = 1.854, 95 % CI, 1.301-2.641) and RFS (p = 0.009, hazard ratio = 1.755, 95 % CI, 1.153-2.671). Moreover, a significant association between the TTT haplotype and relapse in AML patients was observed in this study (p = 0.002, odds ratio = 0.410, 95 % CI, 0.235-0.715). Gene expression level was significantly lower in patients with the TTT haplotype than in the patients with the other haplotypes (p = 0.004).

CONCLUSIONS

The findings suggested the TTT haplotype was possibly related to the OS, RFS, and relapse in Chinese patients with AML.

Association of nitric oxide synthase 3 (NOS3) 894 G>T polymorphism with prognostic outcomes of anthracycline in Chinese patients with acute myeloid leukaemia

The aim of the present study was to investigate the influence of the nitric oxide synthase 3 (NOS3) 894 G>T polymorphism on prognostic outcomes of anthracycline in Chinese patients with de novo intermediate-risk acute myeloid leukaemia (AML) and to examine the gene expression level in relation to genetic variation. In all, 225 Chinese patients with intermediate-risk AML (at the complete remission stage) treated with anthracycline were enrolled in the study. The 894 G>T polymorphism of the NOS3 gene was analysed by allele-specific matrix-assisted laser desorption ionization time-of-flight. Expression of NOS3 mRNA was tested in 72 patients of known genotype for NOS3 894 G>T. The clinical characteristics of these patients were obtained from medical records. Survival analysis showed that patients with AML (GG genotype) had a longer overall survival (OS; P = 0.006). After adjusting for age, gender, leucocyte count, haemoglobin level, platelet level, French, American and Britain (FAB) classification, lactate dehydrogenase levels, Eastern Cooperative Oncology Group Performance Status, nucleophosmin gene and fms-related tyrosine kinase 3 gene, multivariate survival analysis showed that the NOS3 894 G>T polymorphism appeared to be a predicting factor for OS (P = 0.014; hazard ratio = 1.856). However, no significant associations between the NOS3 894 G>T polymorphism and relapse-free survival and relapse in patients with AML were observed. Gene expression levels were significantly higher in patients with the GG genotype than in patients with the GT and TT genotypes (P = 0.033). The findings suggest that the NOS3 894 G>T variant may be a biomarker for the prediction of OS in Chinese patients with AML.

Increased 14-3-3ζ expression in the multidrug-resistant leukemia cell line HL-60/VCR as compared to the parental line mediates cell growth and apoptosis in part through modification of gene expression

BACKGROUND

Acute myeloid leukemia (AML) recurrence is largely a result of multidrug resistance (MDR). We aimed to examine the role of 14-3-3ζ in AML chemosensitivity using HL-60 and vincristine-resistant HL-60/VCR cells.

METHODS

The effects of 14-3-3ζ siRNA on the growth and cell cycle progression of HL-60 and HL-60/VCR cells were determined. The effect of 14-3-3ζ siRNA on topotecan (TPT)-induced apoptosis was evaluated by several assays.

RESULTS

Compared to HL-60 cells, HL-60/VCR cells had increased 14-3-3ζ mRNA and protein expression. Increased mdr-1 mRNA as well as mdr-1, Bcl-2 and Mcl-1 protein expression were observed in HL-60/VCR cells. In both HL-60 and HL-60/VCR cells, 14-3-3ζ was observed in the cytoplasm and nuclear compartments. 14-3-3ζ siRNA significantly reduced HL-60 and HL-60/VCR cell growth after 48 h and increased the proportion of cells in the G0/G1 phase. Moreover, 14-3-3ζ siRNA significantly increased the sensitivity of both HL-60 and HL-60/VCR cells to TPT, possibly through the inhibition of Bcl-2, Mcl-1 and mdr-1 protein expression.

CONCLUSIONS

Silencing of 14-3-3ζ increased the sensitivity of both sensitive and resistant HL-60 cells to TPT-induced apoptosis, possibly through altering the expression of apoptosis-associated proteins, suggesting that it may be a potential target for MDR AML.

Benznidazole modulates cell proliferation in acute leukemia cells

CONTEXT

We have previously reported that benznidazole (BZL), known for its trypanocidal action, has anti-proliferative activity against different cell lines like HeLa and Raw 264.7 among others. At the moment, it has not been reported if the anti-proliferative effect of BZL is similar for non-adherent hematopoietic cells like was reported for adherent cancer cell lines.

OBJECTIVE

We aimed to investigate the efficacy of BZL on the growth of the leukemic cell lines THP-1 and OCI/AML3.

MATERIALS AND METHODS

We evaluated cell proliferation by [³H]-thymidine incorporation and MTT reduction as well as cell death by lactate dehydrogenase (LDH) activity. We assessed apoptosis by flow cytometry for detection of annexin V-positive and propidium iodide-negative cells, along with nuclear morphology by diamidino-2-phenolindole (DAPI) staining. Western blot studies were performed to evaluate changes in cell cycle proteins in BZL-treated cells.

RESULTS

BZL significantly reduced proliferation of both cell lines without inducing cell death. Likewise it produced no significant differences in apoptosis between treated cells and controls. In addition, flow cytometry analysis indicated that BZL caused a larger number of THP-1 cells in G0/G1 phase and a smaller number of cells in S phase than controls. This was accompanied with an increase in the expression of the CDK inhibitor p27 and of cyclin D1, with no significant differences in the protein levels of CDK1, CDK2, CDK4, cyclins E, A and B as compared to controls.

CONCLUSION

BZL inhibits the proliferation of leukemic non-adherent cells by controlling cell cycle at G0/G1 cell phase through up-regulation of p27.

AKN-028 induces cell cycle arrest, downregulation of Myc associated genes and dose dependent reduction of tyrosine kinase activity in acute myeloid leukemia

AKN-028 is a novel tyrosine kinase inhibitor with preclinical activity in acute myeloid leukemia (AML), presently undergoing investigation in a phase I/II study. It is a potent inhibitor of the FMS-like kinase 3 (FLT3) but shows in vitro activity in a wide range of AML samples. In the present study, we have characterized the effects of AKN-028 on AML cells in more detail. AKN-028 induced a dose-dependent G0/1 arrest in AML cell line MV4-11. Treatment with AKN-028 caused significantly altered gene expression in all AML cell types tested (430 downregulated, 280 upregulated transcripts). Subsequent gene set enrichment analysis revealed enrichment of genes associated with the proto-oncogene and cell cycle regulator c-Myc among the downregulated genes in both AKN-028 and midostaurin treated cells. Kinase activity profiling in AML cell lines and primary AML samples showed that tyrosine kinase activity, but not serine/threonine kinase activity, was inhibited by AKN-028 in a dose dependent manner in all samples tested, reaching approximately the same level of kinase activity. Cells sensitive to AKN-028 showed a higher overall tyrosine kinase activity than more resistant ones, whereas serine/threonine kinase activity was similar for all primary AML samples. In summary, AKN-028 induces cell cycle arrest in AML cells, downregulates Myc-associated genes and affect several signaling pathways. AML cells with high global tyrosine kinase activity seem to be more sensitive to the cytotoxic effect of AKN-028 in vitro.

Minimal residual disease in acute myeloid leukemia: coming of age

The achievement of complete hematologic remission (CR) is a prerequisite for cure in acute myeloid leukemia (AML). The conventional definition of CR, based on the morphologic recognition of ≤ 5% of leukemic blasts in the BM, does not provide sufficient insight into the quality of the response. Despite CR rates of 50%-80% (depending on age), the majority of patients with AML relapse within 3-5 years from diagnosis. Therefore, there is great need of more sensitive prognostic factors that can predict relapse. Minimal residual disease (MRD), defined as any measurable disease or leukemia detectable above a certain threshold (defined by the methodology applied), predicts failure to maintain a morphologic CR and affects survival negatively. AML is lagging behind acute lymphoblastic leukemia with respect to the implementation of MRD criteria for guidance during therapy. AML is particularly disadvantaged compared with acute lymphoblastic leukemia in that approximately half of AML patients lack a molecular target suitable for MRD monitoring. The detection of altered antigen (Ag) expression by leukemic myeloblasts is a valid alternative to DNA- or RNA-based MRD assays. Although associated with presenting prognostic factors (eg, cytogenetics and genotype), MRD represents the collective end result of all of the cellular mechanisms that determine a patient's response to a given therapy. Therefore, MRD has 2 potential roles in AML treatment: (1) as a posttherapy prognosticator used to assign patients to optimal postinduction/consolidation therapy, and (2) as an early surrogate end point for the evaluation of therapy efficacy.