Newly diagnosed adult AML and MPAL patients frequently show clonal residual hematopoiesis

Aprepitant Sensitizes Acute Myeloid Leukemia Cells to the Cytotoxic Effects of Cytosine Arabinoside in vitro and in vivo

Purpose

Acute myeloid leukemia (AML) is a complex malignancy characterized by the clonal expansion of immature myeloid precursors. The standard treatment for newly diagnosed AML is chemotherapy consisting of cytosine arabinoside (Ara-C) and anthracyclines with disappointing clinical outcomes and severe adverse effects, such as symptomatic bradycardia, neurotoxicity. Thus, it is promising to treat AML through combination drug therapy to reduce the adverse effects of chemotherapeutics. In our recent published PNAS paper, we reported that NK-1R antagonists, both Aprepitant and SR140333, induce apoptosis of myeloid leukemia cells by inducing oxidative stress through mitochondrial calcium overload. We, therefore, tested the hypothesis of the combination Ara-C with NK-1R antagonist could enhance the efficacy of Ara-C.

Methods

MTT assay was employed to detect the cell proliferation. Flow cytometry was applied to detect the cell cycle and necrosis. PI uptake and LDH release assay were used to detect the disintegration of the plasma membrane. Xenograft model was constructed to explore the effect of combination Ara-C with Aprepitant in vivo.

Results

Our results showed that Aprepitant sensitizes HL60 cells to the cytotoxic effects of Ara-C more than 5-fold by enhancing G0/G1 cell cycle arrest and necrosis in vitro. Furthermore, Nec-1, a specific inhibitor of necroptosis, could recover the cell proliferative viability significantly. Attractively, once every 2-days regimen of Ara-C (5 mg/kg) and Aprepitant (10 mg/kg) via in situ injection dramatically reduced the tumor volume from 2175.0 ± 341.9 mm³ in the vehicle group to 828.4 ± 232.4 mm³ in the combination group without obvious toxicity in human myeloid leukemia xenograft mice.

Conclusion

Taken together, reduced dose of Ara-C combination with moderate Aprepitant provides more effective therapeutical methods for AML treatment in vitro and in vivo with the elimination of the toxicity of Ara-C, which may pay new avenue for the usage of the routine chemotherapy drug Ara-C with low dose to enhance efficacy and reduce toxicity in clinical practice.

Altered neutrophil immunophenotypes in childhood B‑cell precursor acute lymphoblastic leukemia

An increasing number of evidences suggest a genetic predisposition in acute lymphoblastic leukemia (ALL) that might favor the occurrence of the driver genetic alterations. Such genetic background might also translate into phenotypic alterations of residual hematopoietic cells. Whether such phenotypic alterations are present in bone marrow (BM) cells from childhood B-cell precursor (BCP)-ALL remains to be investigated. Here we analyzed the immunophenotypic profile of BM and peripheral blood (PB) maturing/matured neutrophils from 118 children with BCP-ALL and their relationship with the features of the disease. Our results showed altered neutrophil phenotypes in most (77%) BCP-ALL cases. The most frequently altered marker was CD10 (53%), followed by CD33 (34%), CD13 (15%), CD15/CD65 (10%) and CD123 (7%). Of note, patients with altered neutrophil phenotypes had younger age (p = 0.03) and lower percentages of BM maturing neutrophils (p = 0.004) together with greater BM lymphocyte (p = 0.04), and mature B-cell (p = 0.03) counts. No significant association was found between an altered neutrophil phenotype and other disease features. These findings point out the potential existence of an altered residual hematopoiesis in most childhood BCP-ALL cases.

Neutrophils in chronic lymphocytic leukemia are permanently activated and have functional defects

A growing body of studies highlights involvement of neutrophils in cancer development and progression. Our aim was to assess the phenotypic and functional properties of circulating neutrophils from patients with chronic lymphocytic leukemia (CLL). The percentage of CD54+ and CD64+ neutrophils as well as CD54 expression on these cells were higher in CLL patients than in age-matched healthy controls. Neutrophils from CLL produced more reactive oxygen species (ROS) compared to controls in both resting and activated conditions. Lipopolysaccharide-induced production of IL-1β and TNF-a as well as reduced TLR2 expression in neutrophils from CLL than in neutrophils from controls suggesting their tolerant state. Finally, phenotypic alterations of neutrophils, particularly elevation of CD64 and CD54 markers, correlated with disease activity and treatment, and low percentage of neutrophils. Taken together, the alterations in percentage and functional characteristics of neutrophils reflect the clinical course of CLL. Our data provide first evidence that neutrophils in CLL are permanently primed and have functional defects.

Assessment of myeloid and monocytic dysplasia by flow cytometry in de novo AML helps define an AML with myelodysplasia-related changes category

AIMS

In recent years, multiparameter flow cytometry has been increasingly recognised as an important tool in diagnosis of myelodysplastic syndrome and acute myeloid leukaemia (AML). Assessment of myeloid and monocytic 'immunophenotypic' dysplasia by flow cytometry in de novo AML has not been evaluated.

METHODS

97 cases of de novo AML cases were identified and reviewed by three hematopathologists. 'Immunophenotypic' dysplasia was assessed on blasts, monocytes and granulocytes by mean fluorescence intensity.

RESULTS

Using the 2008 WHO classification criteria, there were 53 AML-not otherwise specified (NOS) (55%) and 28 AML with myelodysplasia-related changes (AML-MRC) (29%), while 16 cases were ambiguous as to AML-MRC status due to limited maturing cells for morphologic but adequate events number for immunophenotypic evaluation (AML-not evaluable, 16%). Compared with AML-NOS, granulocytic cells in AML-MRC had higher CD33 expression but lower CD45, CD11b and CD15. Monocytes in AML-MRC had lower expression of CD14, CD56 and CD45. Morphologic dysplasia was associated with significantly lower granulocytic forward scatter, side scatter and CD10 but higher CD33 expression.

CONCLUSIONS

Our results suggest that the workup of AML cases should include flow cytometric assessment of granulocytes and monocytes. This analysis can aid a morphologic impression of multilineage dysplasia in distinguishing AML-MRC from AML-NOS, especially in cases with limited maturing myeloid cells.

Subjects with chronic lymphocytic leukaemia-like B-cell clones with stereotyped B-cell receptors frequently show MDS-associated phenotypes on myeloid cells

An increasing body of evidence suggests the potential occurrence of antigen encounter by the cell of origin in chronic lymphocytic leukaemia (CLL) and CLL-like monoclonal B-cell lymphocytosis (MBL). However, the scenario in which this event might occur remains unknown. In order to gain insight into this scenario we investigated the molecular, cytogenetic and haematological features of 223 CLL-like (n = 84) and CLL (n = 139) clones with stereotyped (n = 32) versus non-stereotyped (n = 191) immunoglobulin heavy chain variable region (IGHV) amino acid sequences. Overall, stereotyped CLL-like MBL and CLL clones showed a unique IGHV profile, associated with higher IGHV1 and lower IGHV3 gene family usage (P = 0·03), longer IGHV complementary determining region 3 (HCDR3) sequences (P = 0·007) and unmutated IGHV (P < 0·001) versus non-stereotyped clones. Whilst the overall size of the stereotyped B-cell clones in peripheral blood did not appear to be associated with the CLL-related cytogenetic profile of B-cells (P > 0·05), it did show a significant association with the presence of myelodysplastic syndrome (MDS)-associated immunophenotypes on peripheral blood neutrophils and/or monocytes (P = 0·01). Altogether our results point to the potential involvement of different selection forces in the expansion of stereotyped vs. non-stereotyped CLL and CLL-like MBL clones, the former being potentially favoured by an underlying altered haematopoiesis.