Acute Myeloid Leukemia Susceptibility Research Articles

FLT3 and IRAK4 Inhibitor Emavusertib in Combination with BH3-Mimetics in the Treatment of Acute Myeloid Leukemia.

Targeting the FLT3 receptor and the IL-1R associated kinase 4 as well as the anti-apoptotic proteins MCL1 and BCL2 may be a promising novel approach in the treatment of acute myeloid leukemia (AML). The FLT3 and IRAK4 inhibitor emavusertib (CA4948), the MCL1 inhibitor S63845, the BCL2 inhibitor venetoclax, and the HSP90 inhibitor PU-H71 were assessed as single agents and in combination for their ability to induce apoptosis and cell death in leukemic cells in vitro. AML cells represented all major morphologic and molecular subtypes, including FLT3-ITD and NPM1 mutant AML cell lines and a variety of patient-derived AML cells. Emavusertib in combination with MCL1 inhibitor S63845 or BCL2 inhibitor venetoclax induced cell cycle arrest and apoptosis in MOLM-13 cells. In primary AML cells, the response to emavusertib was associated with the presence of the FLT3 gene mutation with an allelic ratio >0.5 and the presence of NPM1 gene mutations. S63845 was effective in all tested AML cell lines and primary AML samples. Blast cell percentage was positively associated with the response to CA4948, S63845, and venetoclax, with elevated susceptibility of primary AML with blast cell fraction >80%. Biomarkers of the response to venetoclax included the blast cell percentage and bone marrow infiltration rate, as well as the expression levels of CD11b, CD64, and CD117. Elevated susceptibility to CA4948 combination treatments with S63845 or PU-H71 was associated with FLT3-mutated AML and CD34 < 30%. The combination of CA4948 and BH3-mimetics may be effective in the treatment in FLT3-mutated AML with differential target specificity for MCL1 and BCL2 inhibitors. Moreover, the combination of CA4948 and PU-H71 may be a candidate combination treatment in FLT3-mutated AML.

Ile105Val polymorphism in the GSTP1 gene is associated with susceptibility to acute myeloid leukemia: an updated systematic review and meta-analysis

Background and Objective Several genetic variations are associated with acute myeloid leukemia (AML) susceptibility, including the GSTP1 Ile105Val polymorphism. Even with the existing meta-analysis conducted on the topic, no consensus has been reached since none of the studies available performed in-depth data analysis. Hence, we performed an updated systematic review and meta-analysis in this paper to obtain more precise estimates. Materials and Methods We searched various databases and calculated the odds ratio (OR) and 95% confidence interval (CI) to examine whether the GSTP1 Ile105Val polymorphism is associated with AML susceptibility. Further statistical analysis was also done to obtain more accurate and reliable findings. Results A total of 15 studies are included in the systematic review, but only 9 were included in the meta-analysis due to the studies deviating from the Hardy-Weinberg equilibrium. The analysis showed significantly increased susceptibility to AML in the allelic, co-dominant, and recessive models. Furthermore, subgroup analysis noted increased AML susceptibility in the non-Asian population. Comparing the proportions of the genotypes and alleles showed a significantly higher proportion of the Val/Val genotype and Val allele in the non-Asian cohort. Conclusion The GSTP1 Ile105Val polymorphism is significantly associated with AML susceptibility, especially among non-Asians. Further investigation should be performed to strengthen the current results.

ALDH3A2 Regulates Ferroptosis By Participating in Fatty Acid Synthesis and Finally Lead to Chemotherapy Resistance in Acute Myeloid Leukemia

Chemotherapeutic resistance is a major challenge in the treatment of acute myeloid leukemia (AML). Although increasing the dose of anthracycline drugs improve chemotherapy efficacy and reduce drug resistance, the side effects limit the increase of their dosage. One strategy to improve the therapeutic effects is to improve the efficacy in their limited doses. Ferroptosis is one important way in which Adriamycin exerts cytotoxic effects on AML cells, which was also associated with resistance to Adriamycin. ALDH3A2 is a fatty aldehyde dehydrogenase related to the conversion of fatty aldehydes and fatty acids. Here, we found that ALDH3A2 is a biomarker for chemotherapy-resistant AML, increased expression of ALDH3A2 reduced ferroptosis and cytotoxicity induced by Adriamycin in AML cells. In our studies, we demonstrated that ALDH3A2 regulated ferroptosis and AML drug resistance by participating in fatty acid synthesis. By analyzing the data from TCGA and GTEx databases, we found that ALDH3A2 expression varied in different types of tumor cells. AML patients had higher ALDH3A2 expression than normal tissues. We analyzed the RNA-seq results of 88 leukemia cell lines from the HPA database, and found that 15 out of the top 25% highest ALDH3A2 expression cell lines were AML cell lines, indicating that AML cells had higher ALDH3A2 expression than other types of leukemia cells. We plotted survival curves based on the gene data and clinical survival data from TCGA and GTEx databases. It showed that AML patients with high ALDH3A2 expression had shorter overall survival (OS) than those with low expression. We detected the expression of ALDH3A2 in AML cell lines and primary cells from patients using Western blot and RT-qPCR, respectively. Our data showed that drug-resistant AML cell lines had higher ALDH3A2 expression than their parental cells. The expression of ALDH3A2 in primary cells from AML patients achieving continuous complete remission (CR) within two years was significantly lower than that in the first-line non-remission(C1NR) group and the relapsed/refractory (R/R) group. Besides, the expression of ALDH3A2 is related to certain types of mutation such as CEBPα, FLT3-ITD and RUNX1. To investigate the function of ALDH3A2, we constructed AML cell lines with ALDH3A2 knockdown or overexpression. We found that the increasing ferroptosis level and decreasing cell activity after treatment with the same concentration of Adriamycin was observed in the knockdown group, and overexpression group had the opposite effect. By ELISA and GC-MS, we discovered that there were differences in 4-HNE and fatty acid content between the overexpression group and the control group. It suggested that ALDH3A2 overexpression reduced the cytotoxic 4-HNE and increased the content of heptadecanoic acid, oleic acid, and linoleic acid. We further pretreated AML cells with heptadecanoic acid, oleic acid, and linoleic acid, and found that pretreatment with heptadecanoic acid and oleic acid reduced ferroptosis level and cytotoxicity induced by Adriamycin in AML cells. We also tried to find the regulatory mechanism of ALDH3A2 expression and found that acetylation plays a certain role in it. In conclusion, our studies found that increased expression of ALDH3A2 was related to poor chemotherapy efficacy in AML patients and clarifies the mechanism of ALDH3A2 regulating chemosensitivity in AML. ALDH3A2 degraded the cell toxic product 4-HNE of lipid peroxidation and regulated the proportion and content of heptadecanoic acid, oleic acid, and linoleic acid in cells, which related to ferroptosis and resistance to anthracycline drugs. Downregulating ALDH3A2 could increase AML's susceptibility to chemotherapy which may make it a promising therapy.

Immune checkpoint-related gene polymorphisms are associated with acute myeloid leukemia.

Chemotherapy is still the standard regimen for treating acute myeloid leukemia (AML) and its disappointing efficacy requires the urgent need for new therapeutic targets. It is well known that immune response plays an increasingly significant role in the pathogenesis of AML. We detected nine single nucleotide polymorphisms (SNPs) in immune checkpoint-related genes, including PD1, LAG3, TIM3, and TIGIT in 285 AML inpatients and 324 healthy controls. SNP genotyping was performed on the MassARRAY platform. Furthermore, we analyzed the relationship between the susceptibility and prognosis of AML and the selected SNPs. Our results showed that rs2227982 and rs10204525 in PD1 were significantly associated with susceptibility to AML after false discovery rate correction. PD1 rs10204525 also showed a significant correlation with the response to chemotherapy and risk stratification of AML. Importantly, the AA genotype of PD1 (rs2227982) under the recessive model showed a negative impact on AML prognosis independently. Our results indicate that PD1 SNPs are important for susceptibility and prognosis in AML, which may provide a new therapeutic target for AML patients.

KLK2 single-nucleotide polymorphism rs198977 is associated with increased susceptibility and hyperleukocytosis in AML.

Introduction: Acute myeloid leukemia (AML) is a heterogeneous myeloid malignancy with abnormal molecular diversity. Tissue kallikrein 2 (KLK2) is a kind of serine protease, and has a close relationship with the occurrence and development of malignant tumors. Single nucleotide polymorphism (SNP) of various genes are associated with susceptibility, treatment and survival of AML. Methods: We investigated the association of KLK2 SNPs rs198977 and rs2664155 with AML. We recruited 284 AML patients and 280 healthy controls from the Han population and genotyping KLK2 SNPs rs198977 and rs2664155 by MassARRAY system. Results: Using clinical data from AML patients and controls, including AML susceptibility, blood count, risk stratification, response to induced chemotherapy and survival, our results showed an increased risk of AML susceptibility with KLK2 rs198977 TT genotype in the recessive model. Regarding white blood cell counts in AML patients, the results showed an increased risk of hyperleukocytosis with the TT genotype of KLK2 rs198977 in a codominant model. Moreover, in the recessive model, AML with KLK2 SNPs rs198977 TT genotype had an increased risk of hyperleukocytosis. No significant correlation was found between KLK2 rs2664155 and AML. Discussion: This study suggests that KLK2 rs198977 may be an important genetic factor in the occurrence of AML and hyperleukocytosis in AML, providing a new perspective for disease progression and new therapeutic targets.

Vitamin D-Binding Protein and Acute Myeloid Leukemia: A Genetic Association Analysis in Combination with Vitamin D Levels

Genetic variations in the vitamin D-binding protein (VDBP) may be associated with the plasma level of serum 25-hydroxyvitamin D. Furthermore, vitamin D deficiency increases the risk of acute myeloid leukemia (AML). This study aimed to examine the potential association of VDBP genetic variants (rs7041 and rs4588) with AML susceptibility. The polymorphisms in the VDBP gene and serum 25-hydroxyvitamin D levels were analyzed in 227 AML patients and 240 healthy controls enrolled in this study. Our data revealed that rs4588 CA and AA genotypes were significantly associated with AML susceptibility (OR = 1.483, p = 0.046; OR = 2.154, p = 0.013, respectively) and also with 61.59% vitamin D deficiency in the total group of AML patients. Under the TG co-dominant and dominant models, however, the rs7041 genotypes were significantly associated with AML protection (OR < 0.6; p < 0.05). In addition, vitamin D deficiency was prevalent in vitamin-D-deficient vs. sufficient AML patients who carried rs7041 and rs4588 mutant alleles (OR ≥ 2.2). Indeed, vitamin D deficiency and its interaction with the genetic variants of VDBP could change the risk of AML. Thus, vitamin D deficiency could be considered an important molecular factor in AML risk assessment.

Type 3 Innate Lymphoid Cells Protect Leukemic Blasts from Natural Killer Cell Cytotoxicity in Acute Myeloid Leukemia

Acute myeloid leukemia (AML) is an aggressive form of leukemia originating in the bone marrow (BM) with poor survival outcomes that has been largely resistant to modern cellular and targeted therapies. To improve therapeutic responses, a better understanding of how AML interacts with or evades immune cells is needed. Innate lymphoid cells (ILCs) are a recently discovered class of immune cells that exert their effector functions in an antigen-independent manner. This sentinel function of ILCs likely makes them among the first immune cell types to interact with leukemic blasts. Under homeostatic conditions, type 3 innate lymphoid cells (ILC3s) play important roles in regulating mucosal immunity through production of GM-CSF and IL-22, among others. In the setting of disease, ILC3s are not confined to mucosal tissues, as recent reports have demonstrated expansion of ILC3 populations in solid tumors (Carrega et al., 2015, Nat. Commun). However, the role of ILC3s in AML is unknown. Therefore, we sought to further study and characterize the role of ILC3s in AML biology. We began by utilizing a previously generated Mll-PTD;Flt3-ITD double knock-in murine model of AML that recapitulates human disease (Zorko et al., 2012, Blood). We conducted scRNA-seq analysis of the BM of leukemic mice compared to non-leukemic controls and observed clustering of a Lin-Eomes-Rorc+Il7r+ ILC3 population unique to the AML cohort that was absent in the control group (Figure 1). Furthermore, gene set enrichment analysis showed strong enrichment of an ILC3 gene signature in this cluster. We then validated this observation via flow cytometry and observed an 18.7-fold increase of ILC3s (Lin-Eomes-RORγt+CD127+) in the BM of leukemic mice relative to controls (1.31% +/- 0.20% AML vs 0.07% +/- 0.02% WT, n=5, p<0.001). Taken together, these data demonstrate ILC3 expansion in the leukemic marrow. We next sought to determine the mechanism(s) leading to expansion of this ILC3 population in AML. We have previously implicated skewed differentiation of a common ILC precursor (ILCP) as a mechanism of NK cell dysregulation in AML (Lordo et al., 2021, J Immunol). To determine whether AML cells are capable of skewing differentiation towards ILC3s, we isolated human ILCPs from healthy donor peripheral blood and cultured them under differentiating conditions with or without the AML cell lines U937 or MV411. We observed a significant increase in ILC3 frequency when co-cultured with AML cells (59.78% +/- 3.06% with U937, 57.84% +/- 2.87% with MV411 vs 28.02% +/- 3.89% alone, n=15, p <0.001). This observation was also recapitulated in the BM of a PDX model (23.91% +/- 3.89% with MV411 vs 3.22% +/- 1.01% without MV411, n=10; p<0.0001) and further validated with single cell clonal assays. Overall, these findings suggest ILC3 expansion in AML is due at least in part to skewing of ILC development. Finally, we wanted to characterize the functional consequences of ILC3s on AML cells. To begin to address this, we co-cultured human ILC3s (Lin-CD94-NKp44+) with the AML cell line U937 in transwells for 48 hours before subjecting the AML cells to a natural killer (NK) cell killing assay. We observed significantly reduced NK cell killing of AML cells when co-cultured with ILC3s compared to controls, suggesting ILC3s protect leukemic cells from NK-mediated killing (24.3% killing +/- 3.81% AML Alone vs 14.57% +/- 1.35% AML with ILC3, n=18, p<0.01). To determine what soluble factor(s) mediate this effect, we performed qRT-PCR on ILC3s following incubation with AML cells and found increases in GM-CSF and IL-22 expression in ILC3s relative to ILC3s cultured alone, which was also validated in our murine AML model. Furthermore, colony forming assays using the murine ILC3-like cell line MNK3 with LSKs (Lin-Sca1+Kit+) isolated from leukemic mice showed increased expression of myeloid markers (CD11b, CD11c, and Gr1) on LSK-derived cells when co-incubated with MNK3 cells relative to LSKs cultured alone. This finding suggests ILC3s may promote myeloid skewing of leukemic precursors. Our data create a novel working model of immune evasion in AML in which ILC3 expansion occurs via AML-mediated skewing of ILC development towards ILC3s which then protect AML blasts from NK cell immune surveillance. Current studies are continuing to study the relationship between ILC3s and AML and how to target these interactions to restore AML susceptibility to immune-mediated therapeutic targeting. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

DNMT3A-448A&gt;G nucleotide polymorphism and susceptibility to acute myeloid leukemia in a cohort of Egyptian patients

Background DNA-methyltransferase 3 A (DNMT3A) plays an important role in DNA methylation. Its mutation is the commonest mutated epigenetic regulator in acute myeloid leukemia (AML). However, the relation between DNMT3 polymorphism and AML risk in Egyptian patients is still unknown. Objectives To detect the frequency of DNMT3A-448A&gt;G (rs 1550117) single nucleotide polymorphism in a cohort of adult Egyptian patients with AML and normal controls matched by age, sex, and ethnicity and to assess its effect on the susceptibility of AML. Patients and methods PCR-restriction fragment length polymorphism was the genotyping method used to assess DNMT3A polymorphism in the present case–control study. Results The frequency of the wild (GG), mutant heterozygous (AG), and mutant homozygous (AA) genotypes among patients and controls were 47.90 versus 47.70%, 46.50 versus49.20%, and 5.60 versus 3.10%, respectively (P=0.763, 0.505, and 0.462, respectively), whereas the frequency of A allele was 28.87 versus 27.69% P=0.829. The patients with DNMT3A mutant types (AG, AA, and carrier of the variant Allele of the DNMT3A) were not associated with the risk of AML (odds ratio: 0.548, 0.516, and 0.934; 95% confidence interval: 0.094–3.206, 0.088–3.014, and 0.556-1.60, respectively). Conclusion DNMT3A-448A&gt;G (rs 1550117) polymorphism conferred no risk to AML in our studied Egyptian patients.

Association of TLR4 Rs4986791 Polymorphism and TLR9 Haplotypes with Acute Myeloid Leukemia Susceptibility: A Case-Control Study of Adult Patients.

Toll-like receptors (TLRs) have an important role in innate immunity, and single nucleotide polymorphisms (SNPs) of TLR genes influence the risk of developing hematological malignancies. We aimed to evaluate the effect of TLR2 (rs5743708), TLR4 (rs11536889, rs4986790, rs4986791), TLR9 (rs187084, rs352140, rs5743836) on AML risk, the relation between investigated SNPs and somatic mutations, clinical features, and the overall survival of adult AML patients. All mentioned SNPs were genotyped in 511 AML cases and 503 healthy controls. DNMT3A (R882), FLT3 (D835, ITD), and NPM1 mutations’ status were investigated in AML patients. TLR4 rs4986791 was associated with an increased risk of AML under the dominant model (OR = 1.61, 95% CI: 1.001–2.59). Variant genotypes of the TLR4 rs4986790 or rs4986791 were associated with the odds of developing AML in the codominant model (OR = 3.14; 95% CI: 1.12–8.84; p = 0.032). The TLR9 rs5743836 variant genotype was associated with the NPM1 mutation (p = 0.002). The investigated SNPs were not associated with the DNMT3A, FLT3 mutations and had no significant contribution to the hazard of death after adjusting for covariates. Our findings suggest that TLR4 rs4986791 is associated with AML susceptibility. The combined variant genotypes of TLR4 rs4986790 and rs4986791 increase AML risk, the TLR9 C-G-A haplotype may represent a promising approach to predict a person’s risk for developing AML.

KDM6 Demethylases Integrate DNA Repair Gene Regulation: Loss of KDM6A Sensitizes AML to PARP Inhibition and Potentiates with BCL2 Blockade

Acute myeloid leukemia (AML) is a heterogeneous, aggressive hematological malignancy with dismal prognosis where limited targeted therapies are currently available. Poly-(ADP-ribose)-polymerase (PARP) inhibition has emerged as an important therapeutic arsenal to target homologous recombination-deficient tumors. However, molecular understanding of PARP blockade in the context of epigenetic derangements and transcriptional plasticity in human elderly AML pathogenesis remains unexplored. KDM6 proteins are H3K27 demethylases that critically regulate chromatin architecture in multi-cellularity and tumorigenesis (Tran, Mol Cell Biol 2020). KDM6A escapes X-chr inactivation, and Utx-/- female mice spontaneously develop aging associated myeloid leukemia (Gozdecka, Nat Genet 2018; Sera, Blood 2021). In addition, KDM6A loss of function mutation is implicated in AML relapse (Stief, Leukemia 2020). In contrast, KDM6B primarily exerts an oncogenic function in heme-malignancies. Together, KDM6A and KDM6B play cell type-specific function in leukemia, and KDM6 proteins and associated signaling emerge as important focal point for developing molecular targeted therapy.We identify that KDM6 demethylase activity critically regulates DNA damage repair (DDR) gene expression program in AML. Transcriptome analysis indicated a significant downregulation of expression of DDR genesets in both KDM6A deficient human AML and Utx -/- pre-leukemic cells. Lentiviral shRNA screening performed in response to low-dose γ-irradiation in AML stem cells, revealed a radioprotective function of KDM6A. Expression of KDM6s is regulated by genotoxic stress in a time-dependent manner, and deficiency of JmjC catalytic function impaired DDR transcriptional activation and compromised repair potential. Mechanistically, quantitative ChIP experiments also revealed co-operation between KDM6A and SWI/SNF facilitating dynamic chromatin remodeling at TSS/promoter to induce DDR gene expression. To interrogate changes in chromatin accessibility we performed ATAC-seq analysis in KDM6 deficient AML. Motif enrichment highlighted that while KDM6A depletion led to reduced chromatin access to 140 transcription factors (TFs), only 56 TF binding sites showed increased accessibility. Overall, changes in chromatin accessibility, associated with a reduced binding of DDR regulatory TFs in KDM6 deficient AML, account for a compromised DDR function.In agreement with these findings an array of KDM6 deficient AML cells were more sensitive to PARP inhibition, and pre-clinical mice models xenotransplanted with KDM6A loss of function AML line showed an increased susceptibility to PARP blockade in vivo. FLT3-ITD positive AML with a lower KDM6A expression was more sensitive to olaparib. In addition, olaparib administration significantly reduced bone marrow engraftment of patient-derived xenografts of KDM6A-mutant primary AML. Interestingly, KDM6A expression is upregulated in venetoclax-resistant monocytic-AML compared to venet-sensitive primitive-AML. Using venet responsive isogenic lines we demonstrated that attenuation of KDM6 function increased mitochondrial activity, intracellular ROS levels, de-repressed BCL2 expression, and sensitized AML cells to venetoclax. Additionally, KDM6 loss resulted in transcriptional repression of BCL2A1, commonly associated with venet resistance (Zhang, Nat Cancer 2020). Corroborating these results, dual targeting of PARP with BCL2 was superior to PARP or BCL2 inhibitor monotherapy in inducing primary AML apoptosis, and KDM6A loss further enhanced this synergism.In sum, our study illustrates a molecular mechanistic rationale in support for a novel combination targeted therapy for AML, and posit KDM6A as a molecular determinant for therapeutic efficacy. Intriguingly, KDM6A functions as a gatekeeper of BCL2 and BCL2A1 expression. Similar to TET2 although bi-allelic Utx loss causes evolution to myeloid neoplasms, minimal KDM6 activity is important for survival of human AML cells. KDM6s have been implicated in solid tumors, and both PARP and BCL2 inhibitors are being tested in cancer patients, underscoring a wider scope of application. To conclude, KDM6A unfolds to be a central regulator for susceptibility of AML to both PARP and BCL2 inhibition, expanding the possibility to characterize effective combination targeted therapy for AML in clinical settings. DisclosuresMinden: Astellas: Consultancy. Dick: Celgene, Trillium Therapeutics: Membership on an entity's Board of Directors or advisory committees, Research Funding.

Assessing acute myeloid leukemia susceptibility in rearrangement-driven patients by DNA breakage at topoisomerase II and CCCTC-binding factor/cohesin binding sites.

An initiating DNA double strand break (DSB) event precedes the formation of cancer-driven chromosomal abnormalities, such as gene rearrangements. Therefore, measuring DNA breaks at rearrangement-participating regions can provide a unique tool to identify and characterize susceptible individuals. Here, we developed a highly sensitive and low-input DNA break mapping method, the first of its kind for patient samples. We then measured genome-wide DNA breakage in normal cells of acute myeloid leukemia (AML) patients with KMT2A (previously MLL) rearrangements, compared to that of nonfusion AML individuals, as a means to evaluate individual susceptibility to gene rearrangements. DNA breakage at the KMT2A gene region was significantly greater in fusion-driven remission individuals, as compared to nonfusion individuals. Moreover, we identified select topoisomerase II (TOP2)-sensitive and CCCTC-binding factor (CTCF)/cohesin-binding sites with preferential DNA breakage in fusion-driven patients. Importantly, measuring DSBs at these sites, in addition to the KMT2A gene region, provided greater predictive power when assessing individual break susceptibility. We also demonstrated that low-dose etoposide exposure further elevated DNA breakage at these regions in fusion-driven AML patients, but not in nonfusion patients, indicating that these sites are preferentially sensitive to TOP2 activity in fusion-driven AML patients. These results support that mapping of DSBs in patients enables discovery of novel break-prone regions and monitoring of individuals susceptible to chromosomal abnormalities, and thus cancer. This will build the foundation for early detection of cancer-susceptible individuals, as well as those preferentially susceptible to therapy-related malignancies caused by treatment with TOP2 poisons.

Inhibition of FLT3-ITD and Melk By Small Molecule Inhibitor OTS167 in FLT3 mutant Acute Myeloid Leukemia (AML)

Background and Rationale: Maternal embryonic leucine zipper kinase (MELK) is a Ser/Thr protein kinase that is aberrantly expressed in many tumor types and demonstrated to be important in formation and maintenance of cancer stem cells. We have previously reported that MELK is also aberrantly expressed in AML cell lines and primary patient leukemia cells and is associated with a poor prognosis (Alachkar et. al., Oncotarget, 2014). MELK knockdown resulted in leukemia cell growth inhibition and apoptosis. Based on these preclinical insights, a small molecule inhibitor of MELK kinase activity, OTS167, (OncoTherapy Sciences, Tokyo, Japan) has been developed and is being tested in an early phase clinical trial in advanced myeloid malignancies at the University of Chicago (IRB#15-1373). Here, we report the activity of MELK signaling blockade in AML with FLT3 mutations, which are associated with drug resistance and poor clinical outcomes, and demonstrate synergy with known FLT3 kinase inhibitors.Methods: Both MELK and FLT3-ITD activity were targeted by treating the human AML cell lines MV4:11, MOLM-13, KOCL-48 and KG-1 which aberrantly express MELK as well as a FLT3-ITD, FLT3-TKD or FLT3-WT with the small molecule MELK inhibitor OTS167 alone or in combination with FLT3 kinase inhibitors Crenolanib or Gilteritinib.Results: OTS167 induced cell death of FLT3 mutant cell lines in a dose dependent manner and with IC50 similar to known FLT3 kinase inhibitors (OTS167 IC50 1.8-18.2nM; Crenolanib IC50 2.31-13.8nM; Gilteritinib IC50 4.9-36.3nM). Using isobologram analysis, OTS167 in combination with either Gilteritinib or Crenolanib induced synergistic cell death in FLT3 mutant leukemia cells at 48hrs (Figure 1A), but not in FLT3-WT leukemia cells. We found that OTS167 alone had the effect of inhibiting auto-phosphorylation of FLT3-ITD, as well as inhibiting MELK activity resulting in downregulation of MELK protein expression. Treatment of cells with 50nM OTS167 resulted in loss of FLT3-ITD (Y591) phosphorylation within 1hr, and total FLT3-ITD protein expression within 24 hours (Figure 1B). Loss of FLT3-ITD protein expression occurred in the presence of FLT3 mRNA and was not due to decreased stability of the protein, as treatment with OTS167 in the presence of cycloheximide did not decrease FLT3-ITD lifespan. Notably, the loss of FLT3-ITD protein expression observed with OTS167 treatment was not observed with the same concentration of FLT3 inhibitors Crenolanib or Gilteritinib. In vitro kinase assays using recombinant FLT3-ITD confirmed that OTS167 could act directly to inhibit FLT3-ITD kinase activity at an IC50 of 4.9nM, compared to a reported MELK IC50 of 0.11-1.1nM (Chung, et. al., Oncotarget, 2012). In MV4:11 cells, the constitutive activation of the MAPK, PI3K, and STAT5 signaling pathways by FLT3-ITD is inhibited by 50nM OTS167, similar to inhibition by 50nM FLT3 inhibitors Crenolanib and Gilteritinib (Figure 1C).In addition, treatment with either OTS167 or FLT3 inhibitor resulted in loss of MYC mRNA and protein expression at 3hr, suggesting that more effective downregulation of MYC expression by the combination may increase the susceptibility of FLT3 mutant AML to apoptosis. The inhibition of FLT3-ITD activation and expression after OTS167 treatment was not observed when MELK protein activity was downregulated using siRNA, suggesting the inhibitor may simultaneously target two independent signaling pathways active in cellular transformation. These results indicate that OTS167 may have a dual specificity in FLT3 mutant AML through targeting both aberrant MELK and FLT3 activity.Conclusion: In summary, the MELK inhibitor, OTS167, may be an attractive therapeutic agent for FLT3 mutant AML, with dual targeting resulting in decreased levels of FLT3-ITD protein and kinase activity. These data provide a rationale for testing dual MELK and FLT3 kinase inhibitors in patients with FLT3 mutant AML. [Display omitted] DisclosuresOdenike:CTI/Baxalta: Membership on an entity's Board of Directors or advisory committees; Jazz: Membership on an entity's Board of Directors or advisory committees; Pfizer: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Incyte: Membership on an entity's Board of Directors or advisory committees; AbbVie: Honoraria. Stock:Seattle Genetics: Consultancy, Membership on an entity's Board of Directors or advisory committees; Amgen: Consultancy; Pfizer: Consultancy, Membership on an entity's Board of Directors or advisory committees.

Hypomethylating Agent Leads to Enhanced Immunogenicity of a Dendritic Cell/Acute Myeloid Leukemia Fusion Vaccine and Prolonged Survival in an Immunocompetent Mouse Model

Immunotherapy for acute myeloid leukemia (AML) holds great promise as a modality to overcome tolerance and elicit memory responses needed for durable remissions. Our group pioneered a novel personalized vaccine that targets a broad array of leukemic antigens (Ags) by fusing whole patient-derived AML cells to autologous dendritic cells (DCs). In a clinical trial of AML patients in chemotherapy-induced remission, vaccination induced an expansion of tumor-specific T cells and resulted in prolonged remissions in a subset of patients. Enhancing response to vaccination relies on increasing Ag presentation and overcoming factors in the microenvironment that contribute to tolerance.While the mechanism of action of hypomethylating agents (HMAs) is multifactorial, HMAs are increasingly recognized as exhibiting immunomodulatory functions thought to contribute to therapeutic efficacy. We have previously shown that the HMA SGI-110 augments AML Ag processing and increases AML susceptibility to T cell-mediated killing. In the present study, we aimed to elucidate the effect of HMAs on enhancing Ag presentation and modulating the AML microenvironment as well as to investigate the impact of HMA on the immunogenicity of a DC/AML vaccine.We first investigated the ability of SGI-110 to reverse critical aspects of the AML immunosuppressive milieu and enhance vaccine efficacy. C57BL/6J mice were retro-orbitally inoculated with 1x105 syngeneic TIB-49 AML cells and treated with low-dose SGI-110 (1mg/kg) to assess immunologic effects without preventing engraftment. AML engraftment in the spleen and bone marrow (BM) was similarly observed in treated and control animals. However, SGI-110-treated animals showed decreased PD-1 expression on CD4 T cell splenocytes (mean 3.1% vs. 6.3%; n=4; p=0.01). SGI-110 therapy was also associated with decreased myeloid-derived suppressor cell (MDSC) burden in the BM (n=5; p=0.01) and spleen (n=4; p=0.03) compared to control.Consistent with these findings, treated mice demonstrated increased AML-specific immunity via increased T cells isolated from the BM or spleen that expressed intracellular IFNϒ following ex-vivo exposure to TIB-49 lysate (mean 3% vs. 0.5%; n=5; p=0.02).We then examined the potential synergy of SGI-110 + vaccine in this model. Mice treated with SGI-110 + vaccine showed a significant increase in BM and spleen CD4 (n=5; p=0.05) and CD8 (n=5; p=0.02) T cell IFNϒ in response to tumor lysate as compared to vaccine or SGI-110 alone.To further elucidate the mechanism behind the immune activating effects of HMAs, we investigated the effect of HMA on the endogenous retroviral (ERV) pathway. Activation of this pathway results in increased IFN ß expression leading to increased MHC HLA Class I expression and subsequently, immune stimulation in a solid tumor model (Chiappinelli et al. Cell . 2015). MOLM-14 cells were exposed to low-dose HMA daily X 3 days and analyzed for ERV-3 expression using western blotting (WB). The results showed significant upregulation of ERV-3 expression after treatment. Due to activation of the ERV pathway, increased IFN ß expression was observed with WB analysis. Indeed, analysis of an HLA-A2 positive human AML cell line, THP1, showed significant HLA-A2 upregulation after HMA exposure. Most importantly, HLA-A2 upregulation led to a significant rise in tumor Ag presentation, detected by measuring the binding capacity of a unique T-cell receptor-like antibody using flow cytometric analysis in THP-1 cells.Given these effects, we sought to examine whether treatment with vaccine + SGI-110 would enhance survival in this model. Mice were treated with: vehicle, SGI-110 X 5 days, vaccine, or both agents. Monotherapy with either agent led to a survival advantage compared to untreated mice (p<0.05). Notably, the combination arm further prolonged survival as compared to untreated mice (p<0.05).In conclusion, SGI-110 modulates critical factors contributing to the immunosuppressive milieu in AML by decreasing T cell PD-1 expression and promoting MDSC expansion, resulting in enhanced anti-AML immunity. Moreover, SGI-110 augments the immune response to an autologous DC/AML vaccine in a murine model resulting in a survival benefit. In addition, HMA enhances Ag presentation, in part due to activation of the ERV pathway. The combination of a novel personalized DC/AML fusion vaccine and HMA holds great potential and a clinical trial is being initiated. DisclosuresAvigan:Genus Oncology: Research Funding.

Genome-Wide Association Analyses Identify Variants in IRF4 Associated With Acute Myeloid Leukemia and Myelodysplastic Syndrome Susceptibility.

The role of common genetic variation in susceptibility to acute myeloid leukemia (AML), and myelodysplastic syndrome (MDS), a group of rare clonal hematologic disorders characterized by dysplastic hematopoiesis and high mortality, remains unclear. We performed AML and MDS genome-wide association studies (GWAS) in the DISCOVeRY-BMT cohorts (2,309 cases and 2,814 controls). Association analysis based on subsets (ASSET) was used to conduct a summary statistics SNP-based analysis of MDS and AML subtypes. For each AML and MDS case and control we used PrediXcan to estimate the component of gene expression determined by their genetic profile and correlate this imputed gene expression level with risk of developing disease in a transcriptome-wide association study (TWAS). ASSET identified an increased risk for de novo AML and MDS (OR = 1.38, 95% CI, 1.26-1.51, Pmeta = 2.8 × 10–12) in patients carrying the T allele at s12203592 in Interferon Regulatory Factor 4 (IRF4), a transcription factor which regulates myeloid and lymphoid hematopoietic differentiation. Our TWAS analyses showed increased IRF4 gene expression is associated with increased risk of de novo AML and MDS (OR = 3.90, 95% CI, 2.36-6.44, Pmeta = 1.0 × 10–7). The identification of IRF4 by both GWAS and TWAS contributes valuable insight on the role of genetic variation in AML and MDS susceptibility.

IL-17 A and IL-17 F single nucleotide polymorphisms and acute myeloid leukemia susceptibility and response to induction therapy in Egypt

IL-17 is a proinflammatory cytokine family produced by Th-17 cells and has been found to be implicated in the pathophysiology of many cancers including acute myeloid leukemia (AML). Since single nucleotide polymorphism (SNP) alters the genetic functions and cancer susceptibility, we studied SNPs in two members of IL-17 family, IL-17A (rs2275913; G-197A) and IL-17F (rs763780; A7488G) which are the most common loci associated with IL-17 activity and cancer risk, and correlated the results to AML susceptibility and response to therapy. The study included 200 participants; 100 de novo AML patients and 100 age and sex matched healthy control subjects. SNPs in IL-17A (rs2275913; G-197A) and IL-17F (rs763780; A7488G) were studied using restriction fragment length polymorphism polymerase chain reaction (PCR-RFLP). IL-17A homozygote mutation was more frequent in AML patients compared to control subjects (P = 0.034) and conferred 2.8 fold increased risk of AML (OR = 2.755 [95% CI: 1.078–7.042]). While IL-17F mutation showed no correlation with acute myeloid leukemia susceptibility. Also neither IL-17 A nor IL 17-F mutation showed significant correlation to therapy outcome. In conclusion, IL-17 A homozygote mutation may be associated with AML susceptibility.

Association between TERT gene polymorphisms and acute myeloid leukemia susceptibility in a Chinese population: a case\u2013control study

BackgroundThe aim of this study was to investigate the association between telomerase reverse transcriptase (TERT) gene polymorphisms and acute myeloid leukemia (AML) susceptibility in a Chinese Han population.MethodsA total of 102 AML patients and 108 healthy controls were enrolled in this case–control study. TERT gene rs2853669 and rs2736100 polymorphisms were genotyped via polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Chi-square test was applied to compare polymorphism distributions between case and control groups. The strength of the association between TERT gene polymorphisms and AML susceptibility was evaluated utilizing odds ratio (OR) with corresponding 95% confidence interval (CI).ResultsCC genotype and C allele of rs2736100 polymorphism were more frequent in AML patients (P < 0.05), and individuals carrying CC genotype showed higher risk of suffering from AML (OR = 2.632, 95% CI 1.129–6.133). But for rs2853669 polymorphism, no significant differences were detected in either genotype or allele distributions between groups (P > 0.05).ConclusionsThis study suggested a positive association between TERT gene rs2736100 polymorphism and AML susceptibility in Chinese Han population.

Association Analysis of TP53 rs1042522, MDM2 rs2279744, rs3730485, MDM4 rs4245739 Variants and Acute Myeloid Leukemia Susceptibility, Risk Stratification Scores, and Clinical Features: An Exploratory Study.

This study aimed to explore the associations between the TP53 rs1042522 (TP53 Arg72Pro), MDM2 rs2279744 (MDM2 309T>G), rs3730485 (MDM2 del1518), MDM4 rs4245739 (MDM4 34091 C>A) variants and odds of developing acute myeloid leukemia (AML) in a cohort of 809 adult subjects, consisting of 406 healthy controls and 403 AML patients. Model-based multifactor dimensionality reduction (MB-MDR) framework was used to identify the interactions of the mentioned variants and their association with AML risk. Associations of the mentioned variants with clinical features of AML, somatic mutations, and response to treatment were also evaluated. Significant associations between TP53 rs1042522 and MDM4 rs4245739 variants and AML susceptibility were noticed. MB-MDR and logistic regression analysis revealed an interaction between MDM2 rs2279744 and TP53 rs1042522, between MDM4 rs4245739 and MDM2 rs3730485, as well as significant associations with AML susceptibility. Several associations between the mentioned variants and clinical features of AML and somatic mutations were also noticed. Individually, the variant genotypes of TP53 rs1042522 and MDM4 rs4245739 were associated with AML susceptibility, but their interaction with MDM2 rs2279744 and rs3730485 modulated the risk for AML. The variant genotypes of TP53 rs1042522 were associated with adverse molecular and cytogenetic risk and also with NPM1 mutations.

Dual biomarkers long non-coding RNA GAS5 and its target, NR3C1, contribute to acute myeloid leukemia

Acute myeloid leukemia (AML) is a complex hematological neoplasm with poor prognosis. At present, overwhelming evidence indicates that different genetic abnormalities are relevant to the pathogenesis of AML. Nevertheless, its exact molecular mechanism is still unknown. Recently, it was reported that lncRNAs play crucial roles in tumorigenesis. But, their role in the molecular pathogenesis of AML has not been extensively explored. GAS5, one of the earliest known lncRNAs, has an essential role in the formation and progression of multiple human cancers. It was recently demonstrated that GAS5 acts as a riborepressor of the Glucocorticoid receptor) GR) and abnormal levels of GAS5 may alter response of hematopoietic cells to glucocorticoids. GAS5 can have interaction with the GR that encoded by NR3C1 gene and inhibit its transcriptional activity.To test whether the genetic variants can be associated with AML risk, we genotyped rs55829688 (T > C) polymorphism in GAS5 and three NR3C1 SNPs namely rs6195, rs41423247 and rs6189/rs6190 in a population of 100 Iranian AML patients and 100 healthy subjects.The analysis of the data showed the frequency of alleles and genotypes of rs55829688 and rs6189/rs6190 polymorphisms did not differ between patients and healthy subjects. But, rs41423247 and rs6195 demonstrated a significant correlation with AML risk. The rs6195 was associated with higher AML susceptibility in the co-dominant (OR = 4.58, 95% CI = 2.11–9.981, P < .0001), dominant (OR = 4.55, 95% CI = 2.155–9.613, P < .0001), and over-dominant (OR = 4.43, 95% CI = 2.042–9.621, P < .0001) models. Also, the rs41423247 polymorphism was associated with higher risk of AML in co-dominant (OR = 2.07, 95% CI = 1.171–4.242, P = .012) and dominant (OR = 2.47, 95% CI = 1.192–5.142, P = .010) models. Furthermore, haplotype analysis (rs41423247, rs6189.rs6190, rs6195, and rs55829688 respectively) demonstrated that GGAT, CGGT, and GGGT haplotypes were associated with higher risk of AML in the studied population (p-values = .007, 0.042 and 0.044, respectively). The present study reveals a possible role for NR3C1 in the pathogenesis of AML.

Modelling the Effects of MCM7 Variants, Somatic Mutations, and Clinical Features on Acute Myeloid Leukemia Susceptibility and Prognosis.

The main objective of the study was to evaluate the associations between MCM7 rs2070215, rs1527423, and rs1534309 single nucleotide polymorphisms (SNPs) and acute myeloid leukemia (AML) risk and prognosis. The secondary objectives were to assess if any relationships existed between the mentioned SNPs and FLT3, DNMT3A, NPM1 mutations with clinical outcomes and overall survival (OS) in AML patients. We investigated 281 AML cases and 405 healthy subjects. The results showed a significant association between a variant allele of rs2070215 (p = 0.007), CAT haplotype (p = 0.012), and AML susceptibility. No significant association was found between MCM7 variant genotypes and overall survival of AML patients (p > 0.05), while several associations between somatic mutations, clinical and biological features, and poor OS were noticed. Lactate dehydrogenase (LDH) level ≥ 600 IU/L had a significant effect on the hazard of death (p = 0.004, HR = 1.49, 95% CI: 1.13–1.95). Our study showed that the variant allele of rs2070215, in the allelic model, and CAT haplotype were associated with AML susceptibility. The investigated FLT3, DNMT3A, and NPM1 mutations were associated with the clinical and biological features and poor OS. LDH level ≥ 600 IU/L was associated with an increased hazard of death and this association remained significant when quantifying for effect modification by FLT3 mutation status.

Association between cigarette smoking and the susceptibility of acute myeloid leukemia: a systematic review and meta-analysis.

To elucidate the association between cigarette smoking and the susceptibility of acute myeloid leukemia (AML). We searched relevant articles from PubMed, Embase, and Cochrane by 1st December, 2018. This meta-analysis included 20 case-control studies, involving 7,538 AML patients and 137,924 healthy controls. Studies reported OR and 95%CI of the correlation between cigarette smoking and AML susceptibility were eligible. Subsequently, the included data were weighted by an inverse variance and analyzed using fixed-effects or random-effects model. Subgroup analysis was conducted based on ethnicities and sources of controls. Heterogeneity test was applied for the included articles. Data analyses were conducted using STATA 12.0. Current smokers (OR=1.42, 95%CI= 1.28-1.57; p=0.392) and ever-smokers (OR=1.16, 95%CI=1.05-1.28; p=0.036) were associated with AML susceptibility. In the subgroup analysis by ethnicity, only current smokers (OR=1.45, 95%CI=1.29-1.63; p=0.371) and ever-smokers (OR=1.16, 95%CI=1.03-1.30; p=0.034) of the Caucasian population were associated with AML susceptibility. Stratified analysis based on SOC (source of controls) indicated increased susceptibility of AML in current smokers (OR=1.43, 95%CI=1.26-1.63; p=0.283) and ever-smokers (OR=1.20, 95%CI=1.07-1.35; p=0.078) of the population-based group. Nevertheless, only current smokers in the hospital-based group had increased susceptibility of AML (OR=1.45, 95%CI=1.19-1.76; p=0.198). The risks of AML in ever-smokers (OR=1.04, 95%CI = 0.81-1.35; p=0.054) of the hospital-based group did not remarkably changed. In this meta-analysis, we confirmed the association between cigarette smoking and onset risk of AML, especially in the Caucasian population. High-quality, large-scale researches are required to be conducted in multi-center hospitals for verification.