Contributions
Abstract: PB1617
Type: Publication Only
Session title: Myelodysplastic syndromes - Biology & Translational Research
Background
Myelodysplastic syndrome (MDS) is a heterogeneous clonal disease characterized by the presence of cytopenia in the peripheral blood and dysplasia in the bone marrow. The rate of progression to acute myeloid leukemia (AML) is significant and median time to progression varies from months to years according to biological and clinical feature. Recent preclinical and clinical research indicated the significance of TIM3 signaling checkpoint pathways in progression of MDS and AML and showed the utility of TIM3 inhibition by monoclonal antidotes in inducing clinical remission.
Aims
To investigate the potential targets for therapy of myeloid neoplasms.
Methods
The ability of signaling pathway inhibitors to decrease the expression level of TIM-3 on the membrane surface was tested using the THP-1 cell line of the M2 variant of AML. We tested the panAKT inhibitor MK-2206, mTOR (Rapamycin), PKC (Enzastaurin), RAF (Sorafenib) and ERK (PD98,059). Also the patient's bone marrow with transformation into AML was plated with a 1:20 dilution in RPMI-1640 medium with/without the inhibitor. The surface expression of TIM-3 was assessed by flow cytometry after incubation for 24 and 48h. Additionally, fresh cells from the bone marrow was cultivated only with MK-2206 for 24h.
Results
We found that after the addition of panAKT inhibitor MK-2206 to THP-1 cells and its cultivation for 24 hours, the percentage of TIM-3+ cells decreased from 96.4% to 27.5% at 5 μm and to 16.5% at 10 μm. After 48 hours of cultivation, the sustained decrease persisted up to 40% and 43.2%, respectively. No difference in TIM3 expression after THP-1 cultivation with other inhibitors was observed (p> 0.05). The same pattern was observed in native MDS bone marrow: after its cultivation with 10 μm MK-2206, the percentage of TIM-3+ cells decreased from an average of 10.7% to 5.9%.
Conclusion
A promising direction for further research in AML and MDS is not only blockage of TIM3 signaling by monoclonal antibodies, but also elucidation of pathways leading to TIM3 expression on malignant cells. Further research is required to identify the mechanisms of Akt-mediated TIM3 downregulation.
Keyword(s): Akt, Myeloproliferative disorder, Signal transduction
Abstract: PB1617
Type: Publication Only
Session title: Myelodysplastic syndromes - Biology & Translational Research
Background
Myelodysplastic syndrome (MDS) is a heterogeneous clonal disease characterized by the presence of cytopenia in the peripheral blood and dysplasia in the bone marrow. The rate of progression to acute myeloid leukemia (AML) is significant and median time to progression varies from months to years according to biological and clinical feature. Recent preclinical and clinical research indicated the significance of TIM3 signaling checkpoint pathways in progression of MDS and AML and showed the utility of TIM3 inhibition by monoclonal antidotes in inducing clinical remission.
Aims
To investigate the potential targets for therapy of myeloid neoplasms.
Methods
The ability of signaling pathway inhibitors to decrease the expression level of TIM-3 on the membrane surface was tested using the THP-1 cell line of the M2 variant of AML. We tested the panAKT inhibitor MK-2206, mTOR (Rapamycin), PKC (Enzastaurin), RAF (Sorafenib) and ERK (PD98,059). Also the patient's bone marrow with transformation into AML was plated with a 1:20 dilution in RPMI-1640 medium with/without the inhibitor. The surface expression of TIM-3 was assessed by flow cytometry after incubation for 24 and 48h. Additionally, fresh cells from the bone marrow was cultivated only with MK-2206 for 24h.
Results
We found that after the addition of panAKT inhibitor MK-2206 to THP-1 cells and its cultivation for 24 hours, the percentage of TIM-3+ cells decreased from 96.4% to 27.5% at 5 μm and to 16.5% at 10 μm. After 48 hours of cultivation, the sustained decrease persisted up to 40% and 43.2%, respectively. No difference in TIM3 expression after THP-1 cultivation with other inhibitors was observed (p> 0.05). The same pattern was observed in native MDS bone marrow: after its cultivation with 10 μm MK-2206, the percentage of TIM-3+ cells decreased from an average of 10.7% to 5.9%.
Conclusion
A promising direction for further research in AML and MDS is not only blockage of TIM3 signaling by monoclonal antibodies, but also elucidation of pathways leading to TIM3 expression on malignant cells. Further research is required to identify the mechanisms of Akt-mediated TIM3 downregulation.
Keyword(s): Akt, Myeloproliferative disorder, Signal transduction