EMBRYONIC STEM CELLS ANTIGEN (ESCA) EXPRESSION IN ACUTE MYELOID LEUKEMIA CELLS
(Abstract release date: 05/19/16)
EHA Library. Picot T. 06/09/16; 134540; PB1640
Ms. Tiphanie Picot
Contributions
Contributions
Abstract
Abstract: PB1640
Type: Publication Only
Background
Acute Myeloid Leukemia (AML) is characterized by the expansion and resistance to apoptosis of poorly differentiated myeloid cells. This disease occurs when genetic and epigenetic processes transform an immature hematopoietic stem or progenitor cell, which reacquire self-renewing properties, and retain an undifferentiated state. Long term propagation of the disease is mainly due to a subset of proliferative, undifferentiated population, termed leukemic stem cells (LSC), which give rise to the leukemic clone. The frequency of LSC in the bulk of leukemic cells is highly variable. Several studies have suggested that LSC belongs to the CD34+CD38- compartment and represent the malignant counterpart of normal hematopoietic stem cells (HSC). LSC can be identified by aberrant expression or down regulation of differentiation markers expressed by normal HSC. Self-renewal and lack of differentiation are also features of stem cells and has been associated with the expression of genes including those known as “Yamanaka’s factors”. The products of these genes are surface receptors (SSEA1 and SSEA3) and transcription factors (OCT¾, SOX2, and NANOG). There are some data concerning the abnormal expression of these proteins in solid tumors, but very few data are available in AML.
Aims
The aim of our study was to evaluate the expression of 5 ESCA (SSEA1, SSEA3, NANOG, OCT¾ and SOX2) in leukemic cell lines, and in hematopoietic stem cell (HSC) subsets (CD34+CD38- and CD34+CD38+) from normal bone marrows (NBM) and in 106 samples from AML patients.
Methods
The expression of 5 ESCA was assessed by Multicolor Flow Cytometry and was confirmed by Reverse Transcriptase Polymerase Chain Reaction (RT-PCR).
Results
We observed a high expression of ESCA in AML cell lines (Mean Fluorescence Intensity Ratio MFIR>10, Cycle threshold Ct<40). Their expression was evaluated in CD34+, as well as in the remaining CD45+low “blasts” after basophils and dendritic cells removal. We observed an up-regulation of the transcription factors OCT¾ and SOX2 with 2-fold higher expression (p<0.05) in AML cells as compared to normal cells. These results were associated with the up-regulation of SSEA3. Conversely, SSEA1 protein was down-regulated in LSC (1.7-fold higher expression in normal cells compared to leukemic cells, p<0.05). The expression of OCT¾, SOX2 and SSEA3 was higher in CD34+CD38- than in CD34+CD38+ subsets in HSC as well as in leukemic cells. The level of SSEA1 and NANOG were higher in more differentiated (CD34+CD38+) cells.Significant correlations were observed with recurrent molecular abnormalities. The expression of OCT¾ and SOX2 was lower in promyelocytic leukemia (APL) (p<0.005). SOX2 was also lower in AML with RUNX1-RUNX1T1 rearrangements (but not in AML with CBFβ-MYH11). Instead SSEA1 levels were higher in AML with CBF rearrangements (p<0.001), but not in APL. There was no correlation with other biological characteristics (WBC, other genetics subtypes). We also evaluated the prognostic value of ESCA expression in the 69 patients who received an intensive treatment. The rate of complete remission was not influenced by the level of expression of ESCA. There was a trend (p=0.06) for better overall and leukemia-free survival for patients with high OCT¾ and SOX2 levels, that was unexpected because of the inverse correlation with favourable genetic subtypes.
Conclusion
In conclusion, these results prompt us to evaluate the potential role of ESCA in leukemogenesis and to test the relevance of these markers for better LSC identification. Prognostic value should be assessed in larger series by multivariate analysis.
Session topic: E-poster
Type: Publication Only
Background
Acute Myeloid Leukemia (AML) is characterized by the expansion and resistance to apoptosis of poorly differentiated myeloid cells. This disease occurs when genetic and epigenetic processes transform an immature hematopoietic stem or progenitor cell, which reacquire self-renewing properties, and retain an undifferentiated state. Long term propagation of the disease is mainly due to a subset of proliferative, undifferentiated population, termed leukemic stem cells (LSC), which give rise to the leukemic clone. The frequency of LSC in the bulk of leukemic cells is highly variable. Several studies have suggested that LSC belongs to the CD34+CD38- compartment and represent the malignant counterpart of normal hematopoietic stem cells (HSC). LSC can be identified by aberrant expression or down regulation of differentiation markers expressed by normal HSC. Self-renewal and lack of differentiation are also features of stem cells and has been associated with the expression of genes including those known as “Yamanaka’s factors”. The products of these genes are surface receptors (SSEA1 and SSEA3) and transcription factors (OCT¾, SOX2, and NANOG). There are some data concerning the abnormal expression of these proteins in solid tumors, but very few data are available in AML.
Aims
The aim of our study was to evaluate the expression of 5 ESCA (SSEA1, SSEA3, NANOG, OCT¾ and SOX2) in leukemic cell lines, and in hematopoietic stem cell (HSC) subsets (CD34+CD38- and CD34+CD38+) from normal bone marrows (NBM) and in 106 samples from AML patients.
Methods
The expression of 5 ESCA was assessed by Multicolor Flow Cytometry and was confirmed by Reverse Transcriptase Polymerase Chain Reaction (RT-PCR).
Results
We observed a high expression of ESCA in AML cell lines (Mean Fluorescence Intensity Ratio MFIR>10, Cycle threshold Ct<40). Their expression was evaluated in CD34+, as well as in the remaining CD45+low “blasts” after basophils and dendritic cells removal. We observed an up-regulation of the transcription factors OCT¾ and SOX2 with 2-fold higher expression (p<0.05) in AML cells as compared to normal cells. These results were associated with the up-regulation of SSEA3. Conversely, SSEA1 protein was down-regulated in LSC (1.7-fold higher expression in normal cells compared to leukemic cells, p<0.05). The expression of OCT¾, SOX2 and SSEA3 was higher in CD34+CD38- than in CD34+CD38+ subsets in HSC as well as in leukemic cells. The level of SSEA1 and NANOG were higher in more differentiated (CD34+CD38+) cells.Significant correlations were observed with recurrent molecular abnormalities. The expression of OCT¾ and SOX2 was lower in promyelocytic leukemia (APL) (p<0.005). SOX2 was also lower in AML with RUNX1-RUNX1T1 rearrangements (but not in AML with CBFβ-MYH11). Instead SSEA1 levels were higher in AML with CBF rearrangements (p<0.001), but not in APL. There was no correlation with other biological characteristics (WBC, other genetics subtypes). We also evaluated the prognostic value of ESCA expression in the 69 patients who received an intensive treatment. The rate of complete remission was not influenced by the level of expression of ESCA. There was a trend (p=0.06) for better overall and leukemia-free survival for patients with high OCT¾ and SOX2 levels, that was unexpected because of the inverse correlation with favourable genetic subtypes.
Conclusion
In conclusion, these results prompt us to evaluate the potential role of ESCA in leukemogenesis and to test the relevance of these markers for better LSC identification. Prognostic value should be assessed in larger series by multivariate analysis.
Session topic: E-poster
Abstract: PB1640
Type: Publication Only
Background
Acute Myeloid Leukemia (AML) is characterized by the expansion and resistance to apoptosis of poorly differentiated myeloid cells. This disease occurs when genetic and epigenetic processes transform an immature hematopoietic stem or progenitor cell, which reacquire self-renewing properties, and retain an undifferentiated state. Long term propagation of the disease is mainly due to a subset of proliferative, undifferentiated population, termed leukemic stem cells (LSC), which give rise to the leukemic clone. The frequency of LSC in the bulk of leukemic cells is highly variable. Several studies have suggested that LSC belongs to the CD34+CD38- compartment and represent the malignant counterpart of normal hematopoietic stem cells (HSC). LSC can be identified by aberrant expression or down regulation of differentiation markers expressed by normal HSC. Self-renewal and lack of differentiation are also features of stem cells and has been associated with the expression of genes including those known as “Yamanaka’s factors”. The products of these genes are surface receptors (SSEA1 and SSEA3) and transcription factors (OCT¾, SOX2, and NANOG). There are some data concerning the abnormal expression of these proteins in solid tumors, but very few data are available in AML.
Aims
The aim of our study was to evaluate the expression of 5 ESCA (SSEA1, SSEA3, NANOG, OCT¾ and SOX2) in leukemic cell lines, and in hematopoietic stem cell (HSC) subsets (CD34+CD38- and CD34+CD38+) from normal bone marrows (NBM) and in 106 samples from AML patients.
Methods
The expression of 5 ESCA was assessed by Multicolor Flow Cytometry and was confirmed by Reverse Transcriptase Polymerase Chain Reaction (RT-PCR).
Results
We observed a high expression of ESCA in AML cell lines (Mean Fluorescence Intensity Ratio MFIR>10, Cycle threshold Ct<40). Their expression was evaluated in CD34+, as well as in the remaining CD45+low “blasts” after basophils and dendritic cells removal. We observed an up-regulation of the transcription factors OCT¾ and SOX2 with 2-fold higher expression (p<0.05) in AML cells as compared to normal cells. These results were associated with the up-regulation of SSEA3. Conversely, SSEA1 protein was down-regulated in LSC (1.7-fold higher expression in normal cells compared to leukemic cells, p<0.05). The expression of OCT¾, SOX2 and SSEA3 was higher in CD34+CD38- than in CD34+CD38+ subsets in HSC as well as in leukemic cells. The level of SSEA1 and NANOG were higher in more differentiated (CD34+CD38+) cells.Significant correlations were observed with recurrent molecular abnormalities. The expression of OCT¾ and SOX2 was lower in promyelocytic leukemia (APL) (p<0.005). SOX2 was also lower in AML with RUNX1-RUNX1T1 rearrangements (but not in AML with CBFβ-MYH11). Instead SSEA1 levels were higher in AML with CBF rearrangements (p<0.001), but not in APL. There was no correlation with other biological characteristics (WBC, other genetics subtypes). We also evaluated the prognostic value of ESCA expression in the 69 patients who received an intensive treatment. The rate of complete remission was not influenced by the level of expression of ESCA. There was a trend (p=0.06) for better overall and leukemia-free survival for patients with high OCT¾ and SOX2 levels, that was unexpected because of the inverse correlation with favourable genetic subtypes.
Conclusion
In conclusion, these results prompt us to evaluate the potential role of ESCA in leukemogenesis and to test the relevance of these markers for better LSC identification. Prognostic value should be assessed in larger series by multivariate analysis.
Session topic: E-poster
Type: Publication Only
Background
Acute Myeloid Leukemia (AML) is characterized by the expansion and resistance to apoptosis of poorly differentiated myeloid cells. This disease occurs when genetic and epigenetic processes transform an immature hematopoietic stem or progenitor cell, which reacquire self-renewing properties, and retain an undifferentiated state. Long term propagation of the disease is mainly due to a subset of proliferative, undifferentiated population, termed leukemic stem cells (LSC), which give rise to the leukemic clone. The frequency of LSC in the bulk of leukemic cells is highly variable. Several studies have suggested that LSC belongs to the CD34+CD38- compartment and represent the malignant counterpart of normal hematopoietic stem cells (HSC). LSC can be identified by aberrant expression or down regulation of differentiation markers expressed by normal HSC. Self-renewal and lack of differentiation are also features of stem cells and has been associated with the expression of genes including those known as “Yamanaka’s factors”. The products of these genes are surface receptors (SSEA1 and SSEA3) and transcription factors (OCT¾, SOX2, and NANOG). There are some data concerning the abnormal expression of these proteins in solid tumors, but very few data are available in AML.
Aims
The aim of our study was to evaluate the expression of 5 ESCA (SSEA1, SSEA3, NANOG, OCT¾ and SOX2) in leukemic cell lines, and in hematopoietic stem cell (HSC) subsets (CD34+CD38- and CD34+CD38+) from normal bone marrows (NBM) and in 106 samples from AML patients.
Methods
The expression of 5 ESCA was assessed by Multicolor Flow Cytometry and was confirmed by Reverse Transcriptase Polymerase Chain Reaction (RT-PCR).
Results
We observed a high expression of ESCA in AML cell lines (Mean Fluorescence Intensity Ratio MFIR>10, Cycle threshold Ct<40). Their expression was evaluated in CD34+, as well as in the remaining CD45+low “blasts” after basophils and dendritic cells removal. We observed an up-regulation of the transcription factors OCT¾ and SOX2 with 2-fold higher expression (p<0.05) in AML cells as compared to normal cells. These results were associated with the up-regulation of SSEA3. Conversely, SSEA1 protein was down-regulated in LSC (1.7-fold higher expression in normal cells compared to leukemic cells, p<0.05). The expression of OCT¾, SOX2 and SSEA3 was higher in CD34+CD38- than in CD34+CD38+ subsets in HSC as well as in leukemic cells. The level of SSEA1 and NANOG were higher in more differentiated (CD34+CD38+) cells.Significant correlations were observed with recurrent molecular abnormalities. The expression of OCT¾ and SOX2 was lower in promyelocytic leukemia (APL) (p<0.005). SOX2 was also lower in AML with RUNX1-RUNX1T1 rearrangements (but not in AML with CBFβ-MYH11). Instead SSEA1 levels were higher in AML with CBF rearrangements (p<0.001), but not in APL. There was no correlation with other biological characteristics (WBC, other genetics subtypes). We also evaluated the prognostic value of ESCA expression in the 69 patients who received an intensive treatment. The rate of complete remission was not influenced by the level of expression of ESCA. There was a trend (p=0.06) for better overall and leukemia-free survival for patients with high OCT¾ and SOX2 levels, that was unexpected because of the inverse correlation with favourable genetic subtypes.
Conclusion
In conclusion, these results prompt us to evaluate the potential role of ESCA in leukemogenesis and to test the relevance of these markers for better LSC identification. Prognostic value should be assessed in larger series by multivariate analysis.
Session topic: E-poster
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