Caligiuri, Michael A.

Abstract In CN-AML, mutations of specific genes have prognostic significance and are used for treatment guidance. However, these mutations are in general not mutually exclusive and CN-AML patients (pts) frequently harbor mutational combinations with unclear prognostic significance because of the concurrent presence of mutations with favorable (CEBPA, NPM1) and unfavorable (ASXL1, DNMT3A, IDH1, IDH2, FLT3-ITD, MLL-PTD, RUNX1, TET2, WT1) impact on outcome. Here, we report the frequency and clinical significance of isolated mutations and their combinations in 364 CN-AML pts. Younger [<60 years (y); n=163] and older (≥60 y; n=201) pts were intensively treated on frontline CALGB/Alliance protocols and, per protocol, did not undergo allogeneic stem cell transplantation in first complete remission (CR). Median follow-up for pts alive was 8.7 y. Pts were analyzed centrally for mutations in the ASXL1, CEBPA, DNMT3A, IDH1, IDH2, NPM1, RUNX1, TET2, and WT1 genes and the presence of FLT3-ITD, FLT3-TKD and MLL-PTD. We found that 99% of pts had ≥1 and 88% ≥2 of the 12 mutations. Specifically, 11% of pts had 1 gene mutated (n1), 40% had 2 (n2), 31% 3 (n3), and 18% harbored ≥4 mutated genes (n4). The distribution of the different n groups in younger and older pts was similar (Fig 1). The expected frequency of each mutated gene in every numerical (n) group was calculated as follows: [no. of pts with the mutated gene] x [total no. of mutations in the n group] / [total no. of mutations in all pts], and compared with the observed frequency. CEBPA, IDH2, NPM1, and RUNX1 mutations were overrepresented in the n1 and n2 groups (P<.001, P<.001, P=.002, P=.02, respectively) and thus likely represent “early” events in leukemogenesis. In contrast, DNMT3A, FLT3-ITD, and TET2 mutations were more frequent in the n3 and n4 groups (P=.008, P<.001, P=.02, respectively) suggesting that they are likely “late” events. The distribution among age groups and clinical impact of the “early” mutations (i.e., CEBPA, NPM1, IDH2) presenting as isolated mutations or in combination with other mutations were then investigated. Isolated RUNX1 mutations could not be evaluated due to small sample size. Younger pts were more likely to harbor an isolated “early” mutated gene than older pts (21% v 12%, P=.03). Specifically, isolated CEBPA and NPM1 mutations were more frequent in younger pts compared with the older (7% v 2%, P=.007; 7% v 3%, P=.07, respectively). In pts with isolated CEBPA mutations, these were always bi-allelic. Single “early” mutated genes varied in their impact on CR achievement (CEBPA: 100%, NPM1: 94%, IDH2: 67%), and overall survival (OS; 3-y OS: CEBPA: 87%, NPM1: 69%, IDH2: 22%). Acquisition of additional mutations adversely modified the prognostic significance of favorable “early” mutations in the CEBPA (Fig 2A) and NPM1 (Fig 2B) genes, but left unchanged the unfavorable effect of IDH2 mutations (Fig 2C). Two mutational combinations were exceptions to this: younger pts with both NPM1 and DNMT3A mutations (8 pts) had an excellent prognosis with 3-y OS of 100%; and older pts with concurrent NPM1 and IDH2 mutations (9 pts; all IDH2 mutations were in codon R140) had a high 3-y OS rate of 67%. We conclude that CEBPA and NPM1 mutations mainly define pts with favorable prognosis when they present as single markers, whereas mutated IDH2 predominantly associates with adverse outcome. The NPM1+DNMT3A and NPM1+IDH2 mutational patterns may define novel favorable molecular subtypes in younger and older CN-AML pts, respectively, but these results require corroboration in larger pt cohorts. Disclosures: Mrózek: AMERICAN SOCIETY OF HEMATOLOGY: I will review abstracls submitted for presentation at the 55th ASH Annual Meeting in the 611 category Other. Eisfeld:AMERICAN SOCIETY OF HEMATOLOGY: I will review abstracls submitted for presentation at the 55th ASH Annual Meeting in the 608 category Other.

Significance In this work we report on the previously uncharacterized clinical and biological role for EGFL7 in acute myeloid leukemia (AML). Patients with increased EGFL7 mRNA expression had lower complete remission rates and shorter overall and event-free survival, demonstrating the clinical relevance of EGFL7 expression in cytogenetically normal AML. Our results show that AML blasts are able to synthesize and secrete EGFL7 protein, promoting autocrine blast cell growth. Inhibition of EGFL7 results in decreased proliferation and induces apoptosis of AML cells. Taken together, our data provide the rationale for targeting EGFL7 using blocking antibodies as a therapy for patients with AML.

Abstract Purpose: Oncolytic herpes simplex viruses (oHSV) represent a promising therapy for glioblastoma (GBM), but their clinical success has been limited. Early innate immune responses to viral infection reduce oHSV replication, tumor destruction, and efficacy. Here, we characterized the antiviral effects of macrophages and microglia on viral therapy for GBM. Experimental Design: Quantitative flow cytometry of mice with intracranial gliomas (±oHSV) was used to examine macrophage/microglia infiltration and activation. In vitro coculture assays of infected glioma cells with microglia/macrophages were used to test their impact on oHSV replication. Macrophages from TNFα-knockout mice and blocking antibodies were used to evaluate the biologic effects of TNFα on virus replication. TNFα blocking antibodies were used to evaluate the impact of TNFα on oHSV therapy in vivo. Results: Flow-cytometry analysis revealed a 7.9-fold increase in macrophage infiltration after virus treatment. Tumor-infiltrating macrophages/microglia were polarized toward a M1, proinflammatory phenotype, and they expressed high levels of CD86, MHCII, and Ly6C. Macrophages/microglia produced significant amounts of TNFα in response to infected glioma cells in vitro and in vivo. Using TNFα-blocking antibodies and macrophages derived from TNFα-knockout mice, we discovered TNFα-induced apoptosis in infected tumor cells and inhibited virus replication. Finally, we demonstrated the transient blockade of TNFα from the tumor microenvironment with TNFα-blocking antibodies significantly enhanced virus replication and survival in GBM intracranial tumors. Conclusions: The results of these studies suggest that FDA approved TNFα inhibitors may significantly improve the efficacy of oncolytic virus therapy. Clin Cancer Res; 21(14); 3274–85. ©2015 AACR.

Significance Long noncoding RNAs (lncRNAs) are involved in numerous biological roles including epigenetic regulation, apoptosis, and cell cycle. Whereas lncRNAs contribute to epigenetic gene regulation, metastasis, and prognosis in solid tumors, their role in acute myeloid leukemia (AML) has not been hitherto reported. Here, we show that lncRNA expression profiles are associated with recurrent mutations, clinical features, and outcome in AML. A fraction of these lncRNAs may have a functional role in leukemogenesis. Furthermore, lncRNAs could be used as biomarkers for outcome in AML. The identification of patients likely to achieve complete remission with standard therapy alone, based on lncRNA expression, is a significant advance potentially sparing such patients from other toxicities and focusing investigational approaches on postremission studies.

BACKGROUND Recombinant interleukin‐2 (rIL‐2) induces cellular cytotoxicity against leukemia blasts. Patients with acute myeloid leukemia (AML) in first complete remission (CR) may harbor minimal residual disease that is susceptible to rIL‐2–activated effector cells. METHODS In the Cancer and Leukemia Group B (CALGB) 19808 study, patients with AML in first CR were randomly assigned after all planned chemotherapy to receive a 90‐day course of subcutaneously administered rIL‐2 or no further therapy. The primary objective was to compare disease‐free survival (DFS) between the 2 treatment arms. A total of 534 patients achieved a CR, 214 of whom were randomized. Six courses of low‐dose daily rIL‐2 were given for the expansion of cytotoxic effector cells, each followed by 3‐day high‐dose boluses given to trigger cytotoxicity against minimal residual disease. RESULTS On the protocol‐specified intention‐to‐treat analysis, the hazards ratio for DFS was 0.75 (95% confidence interval, 0.52‐1.09; P = .13); the 5‐year DFS rate was 42% in the observation arm and 53% in the rIL‐2 treatment arm. The hazards ratio for overall survival (OS) was 0.88 (95% confidence interval, 0.54‐1.23; P = .34); the 5‐year OS rate was 58% for the observation arm and 63% for the rIL‐2 treatment arm. Twenty‐five of the 107 patients randomized to treatment with rIL‐2 either refused or were unable to initiate therapy and 30 patients did not complete their assigned therapy. However, significant toxicities were not commonly observed. The trial design did not anticipate the difficulties patients would encounter with protocol compliance. CONCLUSIONS The efficacy of immunotherapy with rIL‐2 administered after intensive postremission treatment was not assessed as planned because of unexpected refusals by patients and/or their physicians to comply with protocol‐directed therapy. Neither DFS nor OS was found to be significantly improved. Cancer 2014;120:1010–1017 . © 2013 American Cancer Society .

Purpose To evaluate the impact of miR-155 on the outcome of adults with cytogenetically normal (CN) acute myeloid leukemia (AML) in the context of other clinical and molecular prognosticators and to gain insight into the leukemogenic role of this microRNA. Patients and Methods We evaluated 363 patients with primary CN-AML. miR-155 levels were measured in pretreatment marrow and blood by NanoString nCounter assays that quantified the expression of the encoding gene MIR155HG. All molecular prognosticators were assessed centrally. miR-155–associated gene and microRNA expression profiles were derived using microarrays. Results Considering all patients, high miR-155 expression was associated with a lower complete remission (CR) rate (P < .001) and shorter disease-free survival (P = .001) and overall survival (OS; P < .001) after adjusting for age. In multivariable analyses, high miR-155 expression remained an independent predictor for a lower CR rate (P = .007) and shorter OS (P < .001). High miR-155 expressers had approximately 50% reduction in the odds of achieving CR and 60% increase in the risk of death compared with low miR-155 expressers. Although high miR-155 expression was not associated with a distinct microRNA expression profile, it was associated with a gene expression profile enriched for genes involved in cellular mechanisms deregulated in AML (eg, apoptosis, nuclear factor-κB activation, and inflammation), thereby supporting a pivotal and unique role of this microRNA in myeloid leukemogenesis. Conclusion miR-155 expression levels are associated with clinical outcome independently of other strong clinical and molecular predictors. The availability of emerging compounds with antagonistic activity to microRNAs in the clinic provides the opportunity for future therapeutic targeting of miR-155 in AML.

Abstract The inv(16)(p13q22)/t(16;16)(p13;q22) in acute myeloid leukemia results in multiple CBFB-MYH11 fusion transcripts, with type A being most frequent. The biologic and prognostic implications of different fusions are unclear. We analyzed CBFB-MYH11 fusion types in 208 inv(16)/t(16;16) patients with de novo disease, and compared clinical and cytogenetic features and the KIT mutation status between type A (n = 182; 87%) and non–type A (n = 26; 13%) patients. At diagnosis, non–type A patients had lower white blood counts (P = .007), and more often trisomies of chromosomes 8 (P = .01) and 21 (P < .001) and less often trisomy 22 (P = .02). No patient with non–type A fusion carried a KIT mutation, whereas 27% of type A patients did (P = .002). Among the latter, KIT mutations conferred adverse prognosis; clinical outcomes of non–type A and type A patients with wild-type KIT were similar. We also derived a fusion-type–associated global gene-expression profile. Gene Ontology analysis of the differentially expressed genes revealed—among others—an enrichment of up-regulated genes involved in activation of caspase activity, cell differentiation and cell cycle control in non–type A patients. We conclude that non–type A fusions associate with distinctclinical and genetic features, including lack of KIT mutations, and a unique gene-expression profile.

AbstractRecently, we showed that increased miR-181a expression was associated with improved outcomes in cytogenetically normal acute myeloid leukemia (CN-AML). Interestingly, miR-181a expression was increased in CN-AML patients harboring CEBPA mutations, which are usually biallelic and associate with better prognosis. CEBPA encodes the C/EBPα transcription factor. We demonstrate here that the presence of N-terminal CEBPA mutations and miR-181a expression are linked. Indeed, the truncated C/EBPα-p30 isoform, which is produced from the N-terminal mutant CEBPA gene or from the differential translation of wild-type CEBPA mRNA and is commonly believed to have no transactivation activity, binds to the miR-181a-1 promoter and up-regulates the microRNA expression. Furthermore, we show that lenalidomide, a drug approved for myelodysplastic syndromes and multiple myeloma, enhances translation of the C/EBPα-p30 isoform, resulting in higher miR-181a levels. In xenograft mouse models, ectopic miR-181a expression inhibits tumor growth. Similarly, lenalidomide exhibits antitumorigenic activity paralleled by increased miR-181a expression. This regulatory pathway may explain an increased sensitivity to apoptosis-inducing chemotherapy in subsets of AML patients. Altogether, our data provide a potential explanation for the improved clinical outcomes observed in CEBPA-mutated CN-AML patients, and suggest that lenalidomide treatment enhancing the C/EBPα-p30 protein levels and in turn miR-181a may sensitize AML blasts to chemotherapy.

Abstract High BAALC expression levels are associated with poor outcome in cytogenetically normal acute myeloid leukemia (CN-AML) patients. Recently, miR-3151 was discovered in intron 1 of BAALC. To evaluate the prognostic significance of miR-3151 expression levels and to gain insight into the biologic and prognostic interplay between miR-3151 and its host, miR-3151 and BAALC expression were measured in pretreatment blood of 179 CN-AML patients. Gene-expression profiling and miRNA-expression profiling were performed using microarrays. High miR-3151 expression was associated with shorter disease-free and overall survival, whereas high BAALC expression predicted failure of complete remission and shorter overall survival. Patients exhibiting high expression of both miR-3151 and BAALC had worse outcome than patients expressing low levels of either gene or both genes. In gene-expression profiling, high miR-3151 expressers showed down-regulation of genes involved in transcriptional regulation, posttranslational modification, and cancer pathways. Two genes, FBXL20 and USP40, were validated as direct miR-3151 targets. The results of the present study show that high expression of miR-3151 is an independent prognosticator for poor outcome in CN-AML and affects different outcome end points than its host gene, BAALC. The combination of both markers identified a patient subset with the poorest outcome. This interplay between an intronic miR and its host may have important biologic implications.

Purpose To determine the frequency of DNMT3A mutations, their associations with clinical and molecular characteristics and outcome, and the associated gene- and microRNA-expression signatures in primary cytogenetically normal acute myeloid leukemia (CN-AML). Patients and Methods Four hundred fifteen previously untreated adults were analyzed for DNMT3A mutations and established prognostic gene mutations and expression markers. Gene- and microRNA-expression profiles were derived using microarrays. Results Younger (< 60 years; n = 181) and older (≥ 60 years; n = 234) patients had similar frequencies of DNMT3A mutations (35.3% v 33.3%). Missense mutations affecting arginine codon 882 (R882-DNMT3A) were more common (n = 92; 62%) than those affecting other codons (non–R882-DNMT3A). DNMT3A-mutated patients did not differ regarding complete remission rate, but had shorter disease-free survival (DFS; P = .03) and, by trend, overall survival (OS; P = .07) than DNMT3A–wild-type patients. In multivariable analyses, DNMT3A mutations remained associated with shorter DFS (P = .01), but not with shorter OS. When analyzed separately, the two DNMT3A mutation types had different significance by age group. Younger patients with non–R882-DNMT3A mutations had shorter DFS (P = .002) and OS (P = .02), whereas older patients with R882-DNMT3A mutations had shorter DFS (P = .005) and OS (P = .002) after adjustment for other clinical and molecular prognosticators. Gene- and microRNA-expression signatures did not accurately predict DNMT3A mutational status. Conclusion DNMT3A mutations are frequent in CN-AML, and their clinical significance seems to be age dependent. DNMT3A-R882 mutations are associated with adverse prognosis in older patients, and non–R882-DNMT3A mutations are associated with adverse prognosis in younger patients. Low accuracy of gene- and microRNA-expression signatures in predicting DNMT3A mutation status suggested that the role of these mutations in AML remains to be elucidated.