Clinical significance of mitochondrial DNA content in acute promyelocytic leukaemia.

Although a growing body of evidence demonstrates that altered mtDNA content (mtDNAc) has clinical implications in several types of solid tumours, its prognostic relevance in acute promyelocytic leukaemia (APL) patients remains largely unknown. Here, we show that patients with higher-than-normal mtDNAc had better outcomes regardless of tumour burden. These results were more evident in patients with low-risk of relapse. The multivariate Cox proportional hazard model demonstrated that high mtDNAc was independently associated with a decreased cumulative incidence of relapse. Altogether, our data highlights the possible role of mitochondrial metabolism in APL patients treated with ATRA.

The ratio of ATP11C/PLSCR1 mRNA transcripts has clinical significance in sickle cell anemia.

One of the physiologic mechanisms responsible to maintain asymmetric phospholipid distribution (in particular phosphatidylserine, PS) in human erythrocyte membranes is orchestrated by the balance between enzymes responsible for active transport of PS from the outer to the inner leaflet (ATP11C) and those whose counteracts these activities (PLSCR1). Using quantitative real-time polymerase chain reaction and standard flow cytometry procedures, we hypothesized that the aberrant expression of either or both ATP11C and PLSCR1 transcripts may disrupt the PS internalization/externalization process and become clinically relevant for patients with sickle cell anemia (SCA). Overall, neither ATP11C/PLSCR1 ratio or ATP11C and PLSCR1 (if analyzed separately) had impact on risk to present acute or chronic organ damage in 178 patients with SCA. By collecting a new set of samples from SCA patients during a vaso-occlusive crisis (VOC, crisis state, 13 patients) and comparing with new samples of patients in steady state (15 patients), we noticed that patients in steady state exhibited mean values of ATP11C/PLSCR1 ratio significantly higher (mean value: 18.2, range, 0.3-53) than those who were in crisis (mean value: 3.7, range, 0.5-9) (P = 0.013). Most importantly, there was a strong inverse correlation between PS exposure and ATP11C/PLSCR1 ratio in sickle erythrocytes (Pearson correlation coefficient, r: - 0.78). Based on these findings, it is conceivable that the ATP11C/PLSCR1 ratio may switch from high to low during a VOC, although the underlying reasons require further investigations.

Combining gene mutation with gene expression analysis improves outcome prediction in acute promyelocytic leukemia.

By combining the analysis of mutations with aberrant expression of genes previously related to poorer prognosis in both acute promyelocytic leukemia (APL) and acute myeloid leukemia, we arrived at an integrative score in APL (ISAPL) and demonstrated its relationship with clinical outcomes of patients treated with all-trans retinoic acid (ATRA) in combination with anthracycline-based chemotherapy. Based on fms-like tyrosine kinase-3-internal tandem duplication mutational status; the ΔNp73/TAp73 expression ratio; and ID1, BAALC, ERG, and KMT2E gene expression levels, we modeled ISAPL in 159 patients (median ISAPL score, 3; range, 0-10). ISAPL modeling identified 2 distinct groups of patients, with significant differences in early mortality (P < .001), remission (P = .004), overall survival (P < .001), cumulative incidence of relapse (P = .028), disease-free survival (P = .03), and event-free survival (P < .001). These data were internally validated by using a bootstrap resampling procedure. At least for patients treated with ATRA and anthracycline-based chemotherapy, ISAPL modeling may identify those who need to be treated differently to maximize their chances for a cure.

High ΔNp73/TAp73 ratio is associated with poor prognosis in acute promyelocytic leukemia.

The TP73 gene transcript is alternatively spliced and translated into the transcriptionally active (TAp73) or inactive (ΔNp73) isoforms, with opposite effects on the expression of p53 target genes and on apoptosis induction. The imbalance between ΔNp73 and TAp73 may contribute to tumorigenesis and resistance to chemotherapy in human cancers, including hematologic malignancies. In acute promyelocytic leukemia (APL), both isoforms are expressed, but their relevance in determining response to therapy and contribution to leukemogenesis remains unknown. Here, we provide the first evidence that a higher ΔNp73/TAp73 RNA expression ratio is associated with lower survival, lower disease-free survival, and higher risk of relapse in patients with APL homogeneously treated with all-trans retinoic acid and anthracycline-based chemotherapy, according to the International Consortium on Acute Promyelocytic Leukemia (IC-APL) study. Cox proportional hazards modeling showed that a high ΔNp73/TAp73 ratio was independently associated with shorter overall survival (hazard ratio, 4.47; 95% confidence interval, 1.64-12.2; P = .0035). Our data support the hypothesis that the ΔNp73/TAp73 ratio is an important determinant of clinical response in APL and may offer a therapeutic target for enhancing chemosensitivity in blast cells.

Prognostic implications of the ID1 expression in acute myeloid leukemia patients treated in a resource-constrained setting.

INTRODUCTION: The aberrant expression of the inhibitor of DNA binding (ID1) gene has been frequently associated with the leukemogenesis and prognostication acute myeloid leukemia (AML), although its clinical importance has never been investigated in patients treated outside well-controlled clinical trials. METHODS: Using quantitative real-time polymerase chain reaction, we investigated the role of the ID1 expression in the clinical outcomes of non-selected patients with acute myeloid leukemia treated in a real-life setting. RESULTS: Overall, 128 patients were enrolled. Patients with high ID1 expression had a lower 3-year overall survival (OS) rate of 9%, with the 95% confidence interval (95%CI) at 3 to 20%, compared to patients with a low ID1 expression (22%, 95%CI: 11 - 34%) (p = 0.037), although these findings did not retain significance after adjustment (hazard ratio (HR): 1.5, 95%CI: 0.98 - 2.28; p = 0.057). The ID1 expression had no impact on post-induction outcomes (disease-free survival, p = 0.648; cumulative incidence of relapse, p = 0.584). CONCLUSIONS: Although we are aware thar our data are confronted with many variables that cannot be fully controlled, including drug unavailability, risk-adapted treatment, comorbidities and the time from diagnosis to treatment initiation, we are firm believers that such an initiative can provide more realistic data on understudied populations, in particular those from low- and middle-income countries.

Association of HMIP1 C-893A polymorphism and disease severity in patients with sickle cell anemia.

INTRODUCTION: Sickle cell anemia (SCA) is a Mendelian disorder with a heterogeneous clinical course. The reasons for this phenotypic diversity are not entirely established, but it is known that high fetal hemoglobin levels lead to a milder course of the disease. Additionally, genetic variants in the intergenic region HBS1L-MYB promote high levels of fetal hemoglobin into adulthood. OBJECTIVE: In the present study, we investigated the HMIP1 C-839A (rs9376092) polymorphism, located at the HBS1L-MYB intergenic region block 1, in SCA patients. METHOD: We analyzed 299 SCA patients followed in two reference centers in Brazil. The HMIP1 C-839A (rs9376092) genotypes were determined by allele specific polymerase chain reactions. Clinical and laboratory data were obtained from patient interviews and medical records. RESULTS: The median fetal hemoglobin levels were higher in patients with the HMIP1 C-839A (rs9376092) AA genotype (CC=6.4%, CA=5.6% and AA=8.6%), but this difference did not reach significance (p=0.194). No association between HMIP1 C-839A (rs9376092) genotypes and other clinical and laboratorial features was detected (p>0.05). CONCLUSION: In summary, our data could not support the previously related association between the HMIP1 C-893A (rs9376092) polymorphism and differential fetal hemoglobin levels.

Molecular-Based Score inspired on metabolic signature improves prognostic stratification for myelodysplastic syndrome.

Deregulated cellular energetics is formally incorporated as an emerging hallmark of cancer, however little is known about its processes in myelodysplastic syndromes (MDS). Using transcriptomic data of CD34+ cells from 159 MDS patients and 17 healthy donors, we selected 37 genes involved in cellular energetics and interrogated about its clinical and prognostic functions. Based on the low expression of ACLY, ANPEP, and PANK1, as well as high expression of PKM and SLC25A5, we constructed our Molecular-Based Score (MBS), that efficiently discriminated patients at three risks groups: favourable risk (n = 28; 3-year overall survival (OS): 100%); intermediate (n = 60; 76% [62-93%]) and adverse (n = 71; 35% [17-61%]). Adverse MBS risk was independently associated with inferior OS (HR = 10.1 [95% CI 1.26-81]; P = 0.029) in multivariable analysis using age, gender and the revised international prognostic score system as confounders. Transcriptional signature revealed that Favourable- and intermediate-risk patients presented enriched molecular programs related to mature myeloid progenitors, cell cycle progression, and oxidative phosphorylation, indicating that this cells differs in their origin, metabolic state, and cell cycle regulation, in comparison to the adverse-risk. Our study provides the first evidence that cellular energetics is transcriptionally deregulated in MDS CD34+ cells and establishes a new useful prognostic score based on the expression of five genes.

A multicenter comparative acute myeloid leukemia study: can we explain the differences in the outcomes in resource-constrained settings?

Outcomes in acute myeloid leukemia (AML) are dependent on patient- and disease-characteristics, treatment, and socioeconomic factors. AML outcomes between resource-constrained and developed countries have not been compared directly. We analyzed two cohorts: from São Paulo state, Brazil (USP, n = 312) and Oxford, United Kingdom (OUH, n = 158). USP cohort had inferior 5-year overall survival compared with OUH (29% vs. 49%, adjusted-p=.027). USP patients have higher early-mortality (23% vs. 6% p<.001) primarily due to multi-resistant Gram-negative bacterial and fungal infections. USP had higher 5-year cumulative incidence of relapse (60% vs. 50%, p=.0022), were less likely to undergo hematopoietic stem cell transplant (HSCT) (28% vs. 75%, p<.001) and waited longer for HSCT (median, 23.8 vs. 7.2 months, p<.001). Three-year survival in relapsed patients was worse in USP than OUH (10% vs. 39%, p<.001). Our study indicates that efforts to improve AML outcomes in Brazil should focus on infection prevention and control, and access to HSCT.

Integrating clinical features with genetic factors enhances survival prediction for adults with acute myeloid leukemia.

The 2017 European LeukemiaNet 2017 acute myeloid leukemia (AML) risk stratification (ELN2017) is widely used for risk-stratifying patients with AML. However, its applicability in low- and middle-income countries is limited because of a lack of full cytogenetic and molecular information at diagnosis. Here, we propose an alternative for risk stratification (the Adapted Genetic Risk [AGR]), which permits cytogenetic or molecular missing data while retaining prognostic power. We first analyzed 167 intensively treated patients with nonacute promyelocytic leukemia AML enrolled in São Paulo, Brazil (Faculdade de Medicina da Universidade de São Paulo), as our training data set, using ELN2017 as the standard for comparison with our AGR. Next, we combined our AGR with clinical prognostic parameters found in a Cox proportional hazards model to create a novel scoring system (survival AML score, SAMLS) that stratifies patients with newly diagnosed AML. Finally, we have used 2 independent test cohorts, Faculdade de Medicina de Ribeirão Preto (FMRP; Brazil, n = 145) and Oxford University Hospitals (OUH; United Kingdom, n = 157) for validating our findings. AGR was statistically significant for overall survival (OS) in both test cohorts (FMRP, P = .037; OUH, P = .012) and disease-free survival in FMRP (P = .04). The clinical prognostic features in SAMLS were age (>45 years), white blood cell count (<1.5 or >30.0 × 103/µL), and low albumin levels (<3.8 g/dL), which were associated with worse OS in all 3 cohorts. SAMLS showed a significant difference in OS in the training cohort (P < .001) and test cohorts (FMRP, P = .0018; OUH, P < .001). Therefore, SAMLS, which incorporates the novel AGR evaluation with clinical parameters, is an accurate tool for AML risk assessment.

NTAL is associated with treatment outcome, cell proliferation and differentiation in acute promyelocytic leukemia.

Non-T cell activation linker (NTAL) is a lipid raft-membrane protein expressed by normal and leukemic cells and involved in cell signaling. In acute promyelocytic leukemia (APL), NTAL depletion from lipid rafts decreases cell viability through regulation of the Akt/PI3K pathway. The role of NTAL in APL cell processes, and its association with clinical outcome, has not, however, been established. Here, we show that reduced levels of NTAL were associated with increased all-trans retinoic acid (ATRA)-induced differentiation, generation of reactive oxygen species, and mitochondrial dysfunction. Additionally, NTAL-knockdown (NTAL-KD) in APL cell lines led to activation of Ras, inhibition of Akt/mTOR pathways, and increased expression of autophagy markers, leading to an increased apoptosis rate following arsenic trioxide treatment. Furthermore, NTAL-KD in NB4 cells decreased the tumor burden in (NOD scid gamma) NSG mice, suggesting its implication in tumor growth. A retrospective analysis of NTAL expression in a cohort of patients treated with ATRA and anthracyclines, revealed that NTAL overexpression was associated with a high leukocyte count (P = 0.007) and was independently associated with shorter overall survival (Hazard Ratio: 3.6; 95% Confidence Interval: 1.17-11.28; P = 0.026). Taken together, our data highlights the importance of NTAL in APL cell survival and response to treatment.

ΔNp73 overexpression promotes resistance to apoptosis but does not cooperate with PML/RARA in the induction of an APL-leukemic phenotype.

Here, we evaluated whether the overexpression of transcriptionally inactive ΔNp73 cooperates with PML/RARA fusion protein in the induction of an APL-leukemic phenotype, as well as its role in vitro in proliferation, myeloid differentiation, and drug-induced apoptosis. Using lentiviral gene transfer, we showed in vitro that ΔNp73 overexpression resulted in increased proliferation in murine bone marrow (BM) cells from hCG-PML/RARA transgenic mice and their wild-type (WT) counterpart, with no accumulation of cells at G2/M or S phases; instead, ΔNp73-expressing cells had a lower rate of induced apoptosis. Next, we evaluated the effect of ΔNp73 on stem-cell self-renewal and myeloid differentiation. Primary BM cells lentivirally infected with human ΔNp73 were not immortalized in culture and did not present significant changes in the percentage of CD11b. Finally, we assessed the impact of ΔNp73 on leukemogenesis or its possible cooperation with PML/RARA fusion protein in the induction of an APL-leukemic phenotype. After 120 days of follow-up, all transplanted mice were clinically healthy and, no evidence of leukemia/myelodysplasia was apparent. Taken together, our data suggest that ΔNp73 had no leukemic transformation capacity by itself and apparently did not cooperate with the PML/RARA fusion protein to induce a leukemic phenotype in a murine BM transplantation model. In addition, the forced expression of ΔNp73 in murine BM progenitors did not alter the ATRA-induced differentiation rate in vitro or induce aberrant cell proliferation, but exerted an important role in cell survival, providing resistance to drug-induced apoptosis.

Clinical impact of BAALC expression in high-risk acute promyelocytic leukemia.

Although overexpression of the brain and acute leukemia, cytoplasmic (BAALC) gene is associated with primary resistant disease and shorter relapse-free, disease-free, and overall survival in different subsets of acute myeloid leukemia (AML), little is known about its clinical impact in acute promyelocytic leukemia (APL). Using real-time reverse transcriptase polymerase chain reaction, we showed that BAALC expression is significantly lower in APL compared with other subsets of AML (P < .001). We also demonstrated that BAALC overexpression was associated with shorter disease-free survival (DFS) (hazard ratio [HR], 4.43; 95% confidence interval [CI], 1.29-15.2; P = .018) in 221 consecutive patients (median age, 35 years; range, 18-82 years) with newly diagnosed APL homogeneously treated with all-trans retinoic acid and anthracycline-based chemotherapy. Cox proportional hazard modeling showed that BAALC overexpression was independently associated with shorter DFS in the total cohort (HR, 5.26; 95% CI, 1.52-18.2; P = .009) and in patients with high-risk disease (ie, those with initial leukocyte counts >10 × 109/L) (HR, 5.3; 95% CI, 1.14-24.5; P = .033). We conclude that BAALC expression could be useful for refining risk stratification in APL, although this needs to be confirmed in independent cohorts.