However, the increasing knowledge of MDS pathogenesis has led to the development of new potential therapies, including HMAs with longer half-life and exposure, inhibition of the antiapoptotic BCL2 protein with venetoclax or inhibition of immune-checkpoint regulatory proteins such as PD-1 or CTLA-4, innate immunity and targeting of CD33/CD3 with multiple monoclonal antibodies.
Herein, we will discuss the mechanism and rationale of BCL-2 inhibition in acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS) with an overview of the selective BCL-2 inhibitor venetoclax.
Based on an integrative gene expression analysis, we combined IRAK1 and BCL2 inhibitors and found that cotreatment more effectively eliminated MDS clones.
Deregulation of apoptosis is one of the important features of AML and to understand the molecular mechanism underlying apoptosis and its contribution to tumor progression, this study aimed to evaluate anti-apoptotic Bcl2 protein expression in AML and correlate with FLT3 parameters for their role in prognosis of disease.Bcl2 and FLT3 protein expression was quantified by flow cytometry on leukemic blasts in total 174 de novo AML, myelodysplastic syndrome (MDS) and aplastic anemia patients.
Co-treatment with VPA and bortezomib on acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS) cell lines resulted in marked inhibition of proliferation and induction of apoptosis, including a striking increase in mitochondrial injury, caspase cascade activation, and altered expression of Bcl-2 family proteins.
The aim of the present study was to examine caspases, granzyme B and bcl-2 family mRNA expression and the degree of apoptosis in the bone marrow (BM) of 46 Myelodysplastic Syndromes (MDS) and to correlate our findings with clinical parameters.
Apoptotic index and bcl-2 do not correlate with key clinical data in patients with myelodysplastic syndrome, while p53 levels show a good correlation with these data and may be a useful parameter to add to current prognostic schemes in this entity.
The mean percentages of bcl-2+ blasts were significantly higher in AML than in MDS (p = 0.01), and in MDS with bone marrow blastosis than in the forms without excess of blasts (p = 0.007).
In addition, we investigated the relationship of apoptosis to the immunohistochemical expression of bcl-2 and p53 in these cases, and the association of apoptosis, bcl-2, and p53 with the leukemic evolution of MDS by examining sequential bone marrow samples of the same patient from the time of initial diagnosis to the time of overt leukemia.
These findings are consistent with the hypothesis that altered balance between cell-death (eg, c-Myc) and cell-survival (eg, Bcl-2) programs were associated with the increased degrees of apoptosis present in MDS hematopoietic precursors and may contribute to the ineffective hematopoiesis in this disorder, in contrast to decreased apoptosis and enhanced leukemic cell survival in AML.
Our findings show that blasts from a majority of MDS cases have bcl-2 expression and that strong bcl-2 expression is not associated with a poor prognosis.