- Email: [email protected]
Tumor Suppressor Role for B55 alpha PP2A Isoform in AML
Abstracts 205
206
Incidence of and risk factors for acute myeloid leukemia involvement of the central nervous system
Tumor Suppressor Role for B55 alpha PP2A Isoform in AML
Uri Rozovski, Maro Ohanian, Farhad Ravandi, Guillermo Garcia-Manero, Sherry Pierce, Jorge Cortes, Zeev Estrov Department of Leukemia, The University of Texas MD Anderson Cancer Center
The exact incidence of central nervous system (CNS) leukemia in adult patients with acute myeloid leukemia (AML) is unknown. Nevertheless, because CNS involvement is thought to be less common in AML than in acute lymphoblastic leukemia, and because induction chemotherapy typically includes cytarabine which penetrates the bloodebrain-barrier, unlike in ALL, routine lumbar puncture (LP) is rarely performed in adult patients with newly diagnosed AML. Objective: To assess the cumulative incidence, the risk factors, and the outcome of CNS involvement in a large cohort of AML patients treated with cytarabine-based and non-cytarabine-based induction chemotherapy. Design and Setting: This is a retrospective study of newly diagnosed patients with AML who received induction chemotherapy between 2000 and 2012 at the University of Texas MD Anderson Cancer Center. Patients: 1412 newly diagnosed patients of all subtypes except for acute promyelocytic leukemia were included. The majority (1370/1412, 97%) underwent diagnostic LP only if signs or symptoms suggestive of CNS disease were suspected. Forty two patients were treated with an investigational protocol that required diagnostic LP at time of diagnosis. CNS leukemia was defined as the presence of leukemic blasts in cytospun cerebrospinal fluid. Results: In 1370 patients for which LP was performed if clinically indicated, CNS disease was detected in 45 (3.3%) patients. In 42 patients who underwent LP at time of diagnosis leukemia blasts were detected in 8 (19%). Patients treated with high-dose cytarabine-based regimens (n¼ 788) and those who were not (n ¼ 582) had similar post-induction rates of CNS involvement. In patients who achieved complete remission after induction chemotherapy, disease free survival and overall survival were significantly shorter if CNS disease was detected. In a univariate analysis, high levels of LDH, a high percentage of BM blasts, African American or Hispanic ethnicity, monoblastic FAB subtype (M5), and FLT3-ITD were predictive for CNS involvement. In the multivariate analysis, only high levels of LDH and African-American ethnicity remained predictive for CNS involvement. Conclusion: The CNS may serve as a sanctuary for residual AML cells and become a source of relapse. Whether CNS prophylaxis will aid in attaining longer DFS remains to be determined.
S180
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Clinical Lymphoma, Myeloma & Leukemia June 2015
Peter P. Ruvolo,1 Vivian R. Ruvolo,1 Rodrigo Jacamo,1 Jared K. Burks,1 Zhihong Zeng,1 Yihua Qiu,1 Suk Y. Yoo,2 Rongqing Pan,1 Numsen Hail, Jr.,1 Marina Konopleva,1,4 George Calin,3 Steven M. Kornblau,1 Michael Andreeff1 1
Division of Molecular Hematology, Department of Leukemia at the University of Texas MD Anderson Cancer Center, Houston, TX, USA; 2
Department of Bioinformatics and Computational Biology at the
University of Texas MD Anderson Cancer Center, Houston, TX, USA; 3
Department of Stem Cell Transplantation and Experimental Thera-
peutics at the University of Texas MD Anderson Cancer Center, Houston, TX, USA; 4Department of Stem Cell Transplantation at the University of Texas MD Anderson Cancer Center, Houston, TX, USA
Background: Acute myeloid leukemia (AML) remains a highly fatal disease despite best efforts to develop novel therapies. Targeting relevant survival kinases is difficult as AML patients with the poorest outcome have multiple active survival kinase cascades. Signal transduction is a dynamic process and one possible mechanism for kinase activation involves loss of protein phosphatase. AKT, PKC, and ERK have all been shown to be regulated by Protein Phosphatase 2A (PP2A). Study Design: We analyzed B55 alpha expression by Reverse Phase Protein Analysis (RPPA) in AML patients. Peripheral blood and bone marrow specimens were collected from 511 patients with newly diagnosed AML evaluated at The University of Texas MD Anderson Cancer Center (MDACC) between September 1999 and March 2007. Samples were acquired during routine diagnostic assessments in accordance with the regulations and protocols approved by the Investigational Review Board of MDACC. B55 alpha expression was correlated with patient survival and disease characteristics including French-AmericanBritish (FAB) classification, cytogenetics, and mutational status. Expression of B55 alpha was also compared to 230 other proteins by RPPA. For proof of principle, B55 alpha was suppressed in OCIAML3 cells and effects on drug resistance, signal transduction, and miR expression was determined. Results: RPPA revealed that in AML cells the B55 alpha PP2A subunit is under expressed, is negatively correlated with AKT activation status, and is unfavorable for remission duration and relapse in patients. RPPA suggested the PP2A B subunit was negatively correlated with a number of proteins including phosphorylated AKT, phosphorylated PKC alpha, and MYC. Suppression of B55 alpha in OCI-AML3 cells demonstrated that loss of the B subunit induces AKT and PKC alpha phosphorylation. Reduction of the B subunit in the AML cells sensitized cells to FTY-720. This finding is consistent with a previous report that FTY-720 induces B55 alpha expression. Suppression of B55 alpha inhibited MYC expression which is likely due to increased levels of the MYC negative regulator B56 alpha. PP2A control of microRNA expression is not well characterized and presently unknown in leukemia. Suppression of B55 alpha induces expression of miR-191-5p (associated with poor survival in AML) and suppresses miR-142-3p (which is mutated in 2% of AML patients) as
Abstracts determined by microarray analysis and validated by qRT-PCR. Future studies will address the mechanism of how PP2A regulates these miRs. Conclusion: Loss of B55 alpha PP2A activity in leukemia can induce diverse survival signaling pathways and allow expression of pro-tumor microRNAs.
207 Impact of Therapy-Related De Novo Acute Myeloid Leukemia on Response and Survival Koji Sasaki, Elias Jabbour, Hagop Kantarjian, Jorge Cortes, Guillermo Garcia-Manero, Gautam Borthakur, Sherry Pierce, Naveen Pemmaraju, Susan O’Brien, Farhad Ravandi Department of Leukemia, The University of Texas MD Anderson Cancer Center
Background: The available data on outcome of patients with therapy-related de novo acute myeloid leukemia (t-de novo AML) without antecedent myelodysplastic syndrome (MDS) are limited. Methods: We retrospectively reviewed the records of patients with newly diagnosed AML who presented to MD Anderson Cancer Center between January 2000 and January 2014. T-de novo AML was defined as at least 20% blasts in bone marrow with a history of any previous cytotoxic chemotherapy or radiation therapy and without antecedent MDS. The overall survival (OS) and leukemia-
free survival (LFS) in patients with t-de novo AML were compared to those with de novo AML with normal karyotype (NK) or complex karyotype (CK). Results: Of 1677 patients with newly diagnosed AML, 383 had de novo NK-AML, 218 had de novo CKAML, and 187 had t-de novo AML. The median follow-up was 9.3 months (range, 0.2-161.0). Patient characteristics and outcomes are summarized in Table 1. Of the 187 patients with t-de novo AML, 69 had a history of lymphoma; 63, breast cancer; 10, colon cancer; 10, sarcoma; and 69, another type of cancer. Fifteen of the patients with t-de novo AML (8%) had a favorable-risk karyotype, 53 patients (28%) an intermediate-risk karyotype, and 119 patients (64%) a poor-risk karyotype. The median LFS durations in t-de novo AML, NK-AML, and CK-AML were 7 months (95% confidence interval [CI], 5.1-8.7), 19 months (95%CI, 13.0-25.2), and 6 months (95%CI, 9.0-13.5) (P <0.001), respectively. The median OS durations in t-de novo AML, NK-AML, and CK-AML were 7 months (95% CI, 5.9-8.9), 21 months (95%CI, 16.2-25.5), and 12 months (95%CI, 10.6-13.5) (P <0.001), respectively. The results of univariate and multivariate analyses associated with OS are summarized in Table 1. Multivariate analysis identified age over 60, white blood cell count >100 103/mL, platelets <30 0 103/mL, nonfavorable cytogenetic abnormalities, positive RAS mutation, and the absence of complete remission or complete remission with incomplete platelet recovery as poor prognostic features related to OS. Conclusion: LFS and OS for patients with t-de novo AML were shorter than those for patients with NK-AML but did not differ significantly from those for patients with CK-AML.
Table 1 Characteristics and Outcomes of Patients with De Novo AML t-de novo AML (n[ 187) Age at diagnosis, median, years (range)
64 (21-89)
de novo NK-AML (n[ 383) 63 (17-90)
de novo CK-AML (n[ 218)
Prior radiation therapy, No. (%)
101 (54)
Prior chemotherapy, No. (%)
186 (99)
0
0
WBC count at diagnosis, median, 103/mL (range)
3.2 (0.2-191)
4.3 (0.2-390.0)
2.9 (0.5-278.2)
Hgb at diagnosis, median, g/dL (range)
9.1 (4.5-12.9)
9.1 (4-14.6)
9.0 (2.5-14.2)
Plt count at diagnosis, median, 103/mL (range)
34 (4-454)
51 (3-469)
42 (2-319)
LDH at diagnosis, median, IU/L (range)
1359 (210-22090)
0
1189 (200-42000)
P value
67 (18-87) 0
1274 (231-20572)
PB blast percentage at diagnosis, median (range)
8 (0-98)
9.5 (0-98)
10 (0-98)
BM blast percentage at diagnosis, median (range)
41 (0-96)
44 (0-96)
33 (0-97)
17 (9)
96 (25)
5 (2)
Molecular genetic abnormalities at diagnosis, No. (%) FLT3-ITD FLT3-D835
6 (3)
23 (6)
1 (1)
NPM1
7 (4)
104 (27)
4 (2)
JAK2
3 (2)
6 (2)
8 (4)
RAS
17 (9)
50 (13)
8 (4)
Clinical Lymphoma, Myeloma & Leukemia June 2015
- S181
206
Incidence of and risk factors for acute myeloid leukemia involvement of the central nervous system
Tumor Suppressor Role for B55 alpha PP2A Isoform in AML
Uri Rozovski, Maro Ohanian, Farhad Ravandi, Guillermo Garcia-Manero, Sherry Pierce, Jorge Cortes, Zeev Estrov Department of Leukemia, The University of Texas MD Anderson Cancer Center
The exact incidence of central nervous system (CNS) leukemia in adult patients with acute myeloid leukemia (AML) is unknown. Nevertheless, because CNS involvement is thought to be less common in AML than in acute lymphoblastic leukemia, and because induction chemotherapy typically includes cytarabine which penetrates the bloodebrain-barrier, unlike in ALL, routine lumbar puncture (LP) is rarely performed in adult patients with newly diagnosed AML. Objective: To assess the cumulative incidence, the risk factors, and the outcome of CNS involvement in a large cohort of AML patients treated with cytarabine-based and non-cytarabine-based induction chemotherapy. Design and Setting: This is a retrospective study of newly diagnosed patients with AML who received induction chemotherapy between 2000 and 2012 at the University of Texas MD Anderson Cancer Center. Patients: 1412 newly diagnosed patients of all subtypes except for acute promyelocytic leukemia were included. The majority (1370/1412, 97%) underwent diagnostic LP only if signs or symptoms suggestive of CNS disease were suspected. Forty two patients were treated with an investigational protocol that required diagnostic LP at time of diagnosis. CNS leukemia was defined as the presence of leukemic blasts in cytospun cerebrospinal fluid. Results: In 1370 patients for which LP was performed if clinically indicated, CNS disease was detected in 45 (3.3%) patients. In 42 patients who underwent LP at time of diagnosis leukemia blasts were detected in 8 (19%). Patients treated with high-dose cytarabine-based regimens (n¼ 788) and those who were not (n ¼ 582) had similar post-induction rates of CNS involvement. In patients who achieved complete remission after induction chemotherapy, disease free survival and overall survival were significantly shorter if CNS disease was detected. In a univariate analysis, high levels of LDH, a high percentage of BM blasts, African American or Hispanic ethnicity, monoblastic FAB subtype (M5), and FLT3-ITD were predictive for CNS involvement. In the multivariate analysis, only high levels of LDH and African-American ethnicity remained predictive for CNS involvement. Conclusion: The CNS may serve as a sanctuary for residual AML cells and become a source of relapse. Whether CNS prophylaxis will aid in attaining longer DFS remains to be determined.
S180
-
Clinical Lymphoma, Myeloma & Leukemia June 2015
Peter P. Ruvolo,1 Vivian R. Ruvolo,1 Rodrigo Jacamo,1 Jared K. Burks,1 Zhihong Zeng,1 Yihua Qiu,1 Suk Y. Yoo,2 Rongqing Pan,1 Numsen Hail, Jr.,1 Marina Konopleva,1,4 George Calin,3 Steven M. Kornblau,1 Michael Andreeff1 1
Division of Molecular Hematology, Department of Leukemia at the University of Texas MD Anderson Cancer Center, Houston, TX, USA; 2
Department of Bioinformatics and Computational Biology at the
University of Texas MD Anderson Cancer Center, Houston, TX, USA; 3
Department of Stem Cell Transplantation and Experimental Thera-
peutics at the University of Texas MD Anderson Cancer Center, Houston, TX, USA; 4Department of Stem Cell Transplantation at the University of Texas MD Anderson Cancer Center, Houston, TX, USA
Background: Acute myeloid leukemia (AML) remains a highly fatal disease despite best efforts to develop novel therapies. Targeting relevant survival kinases is difficult as AML patients with the poorest outcome have multiple active survival kinase cascades. Signal transduction is a dynamic process and one possible mechanism for kinase activation involves loss of protein phosphatase. AKT, PKC, and ERK have all been shown to be regulated by Protein Phosphatase 2A (PP2A). Study Design: We analyzed B55 alpha expression by Reverse Phase Protein Analysis (RPPA) in AML patients. Peripheral blood and bone marrow specimens were collected from 511 patients with newly diagnosed AML evaluated at The University of Texas MD Anderson Cancer Center (MDACC) between September 1999 and March 2007. Samples were acquired during routine diagnostic assessments in accordance with the regulations and protocols approved by the Investigational Review Board of MDACC. B55 alpha expression was correlated with patient survival and disease characteristics including French-AmericanBritish (FAB) classification, cytogenetics, and mutational status. Expression of B55 alpha was also compared to 230 other proteins by RPPA. For proof of principle, B55 alpha was suppressed in OCIAML3 cells and effects on drug resistance, signal transduction, and miR expression was determined. Results: RPPA revealed that in AML cells the B55 alpha PP2A subunit is under expressed, is negatively correlated with AKT activation status, and is unfavorable for remission duration and relapse in patients. RPPA suggested the PP2A B subunit was negatively correlated with a number of proteins including phosphorylated AKT, phosphorylated PKC alpha, and MYC. Suppression of B55 alpha in OCI-AML3 cells demonstrated that loss of the B subunit induces AKT and PKC alpha phosphorylation. Reduction of the B subunit in the AML cells sensitized cells to FTY-720. This finding is consistent with a previous report that FTY-720 induces B55 alpha expression. Suppression of B55 alpha inhibited MYC expression which is likely due to increased levels of the MYC negative regulator B56 alpha. PP2A control of microRNA expression is not well characterized and presently unknown in leukemia. Suppression of B55 alpha induces expression of miR-191-5p (associated with poor survival in AML) and suppresses miR-142-3p (which is mutated in 2% of AML patients) as
Abstracts determined by microarray analysis and validated by qRT-PCR. Future studies will address the mechanism of how PP2A regulates these miRs. Conclusion: Loss of B55 alpha PP2A activity in leukemia can induce diverse survival signaling pathways and allow expression of pro-tumor microRNAs.
207 Impact of Therapy-Related De Novo Acute Myeloid Leukemia on Response and Survival Koji Sasaki, Elias Jabbour, Hagop Kantarjian, Jorge Cortes, Guillermo Garcia-Manero, Gautam Borthakur, Sherry Pierce, Naveen Pemmaraju, Susan O’Brien, Farhad Ravandi Department of Leukemia, The University of Texas MD Anderson Cancer Center
Background: The available data on outcome of patients with therapy-related de novo acute myeloid leukemia (t-de novo AML) without antecedent myelodysplastic syndrome (MDS) are limited. Methods: We retrospectively reviewed the records of patients with newly diagnosed AML who presented to MD Anderson Cancer Center between January 2000 and January 2014. T-de novo AML was defined as at least 20% blasts in bone marrow with a history of any previous cytotoxic chemotherapy or radiation therapy and without antecedent MDS. The overall survival (OS) and leukemia-
free survival (LFS) in patients with t-de novo AML were compared to those with de novo AML with normal karyotype (NK) or complex karyotype (CK). Results: Of 1677 patients with newly diagnosed AML, 383 had de novo NK-AML, 218 had de novo CKAML, and 187 had t-de novo AML. The median follow-up was 9.3 months (range, 0.2-161.0). Patient characteristics and outcomes are summarized in Table 1. Of the 187 patients with t-de novo AML, 69 had a history of lymphoma; 63, breast cancer; 10, colon cancer; 10, sarcoma; and 69, another type of cancer. Fifteen of the patients with t-de novo AML (8%) had a favorable-risk karyotype, 53 patients (28%) an intermediate-risk karyotype, and 119 patients (64%) a poor-risk karyotype. The median LFS durations in t-de novo AML, NK-AML, and CK-AML were 7 months (95% confidence interval [CI], 5.1-8.7), 19 months (95%CI, 13.0-25.2), and 6 months (95%CI, 9.0-13.5) (P <0.001), respectively. The median OS durations in t-de novo AML, NK-AML, and CK-AML were 7 months (95% CI, 5.9-8.9), 21 months (95%CI, 16.2-25.5), and 12 months (95%CI, 10.6-13.5) (P <0.001), respectively. The results of univariate and multivariate analyses associated with OS are summarized in Table 1. Multivariate analysis identified age over 60, white blood cell count >100 103/mL, platelets <30 0 103/mL, nonfavorable cytogenetic abnormalities, positive RAS mutation, and the absence of complete remission or complete remission with incomplete platelet recovery as poor prognostic features related to OS. Conclusion: LFS and OS for patients with t-de novo AML were shorter than those for patients with NK-AML but did not differ significantly from those for patients with CK-AML.
Table 1 Characteristics and Outcomes of Patients with De Novo AML t-de novo AML (n[ 187) Age at diagnosis, median, years (range)
64 (21-89)
de novo NK-AML (n[ 383) 63 (17-90)
de novo CK-AML (n[ 218)
Prior radiation therapy, No. (%)
101 (54)
Prior chemotherapy, No. (%)
186 (99)
0
0
WBC count at diagnosis, median, 103/mL (range)
3.2 (0.2-191)
4.3 (0.2-390.0)
2.9 (0.5-278.2)
Hgb at diagnosis, median, g/dL (range)
9.1 (4.5-12.9)
9.1 (4-14.6)
9.0 (2.5-14.2)
Plt count at diagnosis, median, 103/mL (range)
34 (4-454)
51 (3-469)
42 (2-319)
LDH at diagnosis, median, IU/L (range)
1359 (210-22090)
0
1189 (200-42000)
P value
67 (18-87) 0
1274 (231-20572)
PB blast percentage at diagnosis, median (range)
8 (0-98)
9.5 (0-98)
10 (0-98)
BM blast percentage at diagnosis, median (range)
41 (0-96)
44 (0-96)
33 (0-97)
17 (9)
96 (25)
5 (2)
Molecular genetic abnormalities at diagnosis, No. (%) FLT3-ITD FLT3-D835
6 (3)
23 (6)
1 (1)
NPM1
7 (4)
104 (27)
4 (2)
JAK2
3 (2)
6 (2)
8 (4)
RAS
17 (9)
50 (13)
8 (4)
Clinical Lymphoma, Myeloma & Leukemia June 2015
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