Alkynyl nicotinamides show antileukemic activity in drug-resistant acute myeloid leukemia.

Activating mutations of FLT3 contribute to deregulated hematopoietic stem and progenitor cell (HSC/Ps) growth and survival in patients with acute myeloid leukemia (AML), leading to poor overall survival. AML patients treated with investigational drugs targeting mutant FLT3, including Quizartinib and Crenolanib, develop resistance to these drugs. Development of resistance is largely due to acquisition of cooccurring mutations and activation of additional survival pathways, as well as emergence of additional FLT3 mutations. Despite the high prevalence of FLT3 mutations and their clinical significance in AML, there are few targeted therapeutic options available. We have identified 2 novel nicotinamide-based FLT3 inhibitors (HSN608 and HSN748) that target FLT3 mutations at subnanomolar concentrations and are potently effective against drug-resistant secondary mutations of FLT3. These compounds show antileukemic activity against FLT3ITD in drug-resistant AML, relapsed/refractory AML, and in AML bearing a combination of epigenetic mutations of TET2 along with FLT3ITD. We demonstrate that HSN748 outperformed the FDA-approved FLT3 inhibitor Gilteritinib in terms of inhibitory activity against FLT3ITD in vivo.

Expression, Function, and Significance of Non B Cell-Derived Immunoglobulin in Haematological System.

Acute myeloid leukaemia (AML) is a collection of genetically diverse diseases characterised by abnormal proliferation of immature haematopoietic cells and disruption of normal haematopoiesis. Myeloid cells and lymphocytes originate from different haematopoietic precursors within the bone marrow. It has been traditionally assumed that myeloid cells cannot produce immunoglobulin (Ig), a marker of B cells and plasma cells. However, in recent years, all five Ig classes have been detected in CD34+ haematopoietic stem cells, mature monocytes and neutrophils, differentiated macrophages and tumour-associated macrophages, acute myeloid leukaemia cell lines, as well as myeloblasts of AML. The rearranged V(D)J sequences exhibit unique restricted or biased V gene usage and evidence of somatic mutation. Furthermore, AML-derived Igs could promote cell proliferation, induce apoptosis, and enhance migration. Elevated levels of Ig expression predict inferior clinical outcomes. These findings indicate that AML-derived Ig plays a role in AML pathogenesis and progression, and could serve as a novel biomarker for risk stratification, disease monitoring, and targeted therapy. In this chapter, we provide a comprehensive review of recent literature on the expression, function, and significance of non B cell-derived Ig in the haematological system, with a focus on AML.

Emerging role of glutathione peroxidase 4 in myeloid cell lineage development and acute myeloid leukemia.

Phospholipid Hydroperoxide Gluthatione Peroxidase also called Glutathione Peroxidase 4 is one of the 25 described human selenoproteins. It plays an essential role in eliminating toxic lipid hydroxy peroxides, thus inhibiting ferroptosis and favoring cell survival. GPX4 is differentially expressed according to myeloid differentiation stage, exhibiting lower expression in hematopoietic stem cells and polymorphonuclear leucocytes, while harboring higher level of expression in common myeloid progenitors and monocytes. In addition, GPX4 is highly expressed in most of acute myeloid leukemia (AML) subtypes compared to normal hematopoietic stem cells. High GPX4 expression is consistently correlated to poor prognosis in patients suffering AML. However, the role of GPX4 in the development of the myeloid lineage and in the initiation and progression of myeloid leukemia remains poorly explored. Given its essential role in the detoxification of lipid hydroperoxides, and its overexpression in most of myeloid malignancies, GPX4 inhibition has emerged as a promising therapeutic strategy to specifically trigger ferroptosis and eradicate myeloid leukemia cells. In this review, we describe the most recent advances concerning the role of GPX4 and, more generally ferroptosis in the myeloid lineage and in the emergence of AML. We also discuss the therapeutic interest and limitations of GPX4 inhibition alone or in combination with other drugs as innovative therapies to treat AML patients.

C-JUN overexpressing CAR-T cells in acute myeloid leukemia: preclinical characterization and phase I trial.

Chimeric antigen receptor (CAR) T cells show suboptimal efficacy in acute myeloid leukemia (AML). We find that CAR T cells exposed to myeloid leukemia show impaired activation and cytolytic function, accompanied by impaired antigen receptor downstream calcium, ZAP70, ERK, and C-JUN signaling, compared to those exposed to B-cell leukemia. These defects are caused in part by the high expression of CD155 by AML. Overexpressing C-JUN, but not other antigen receptor downstream components, maximally restores anti-tumor function. C-JUN overexpression increases costimulatory molecules and cytokines through reinvigoration of ERK or transcriptional activation, independent of anti-exhaustion. We conduct an open-label, non-randomized, single-arm, phase I trial of C-JUN-overexpressing CAR-T in AML (NCT04835519) with safety and efficacy as primary and secondary endpoints, respectively. Of the four patients treated, one has grade 4 (dose-limiting toxicity) and three have grade 1-2 cytokine release syndrome. Two patients have no detectable bone marrow blasts and one patient has blast reduction after treatment. Thus, overexpressing C-JUN endows CAR-T efficacy in AML.

SLPI overexpression in hMSCs could be implicated in the HSC gene expression profile in AML.

Acute myeloid leukaemia (AML) is a severe haematological neoplasm that originates from the transformation of haematopoietic stem cells (HSCs) into leukaemic stem cells (LSCs). The bone marrow (BM) microenvironment, particularly that of mesenchymal stromal cells (hMSCs), plays a crucial role in the maintenance of HSCs. In this context, we explored whether alterations in the secretome of hMSCs derived from AML patients (hMSC-AML) could impact HSC gene expression. Proteomic analysis revealed that the secretome of coculture assays with hMSC-AMLs and HSC from healthy donor is altered, with increased levels of secretory leukocyte protease inhibitor (SLPI), a protein associated with important processes for maintenance of the haematopoietic niche that has already been described to be altered in several tumours. Increased SLPI expression was also observed in the BM plasma of AML patients. Transcriptome analysis of HSCs cocultured with hMSC-AML in comparison with HSCs cocultured with hMSC-HD revealed altered expression of SLPI target genes associated with the cell cycle, proliferation, and apoptosis. Important changes were identified, such as increased expression levels of CCNA2, CCNE2, CCND2, CD133 and CDK1 and decreased levels of CDKN2A and IGFBP3, among others. Overall, these findings suggest that the altered secretome of coculture assays with hMSC-AMLs and HSC from healthy donor, particularly increased SLPI expression, can contribute to gene expression changes in HSCs, potentially influencing important molecular mechanisms related to AML development and progression.

A biochemical assessment of apoptosis-inducing impact of Salinomycin in combination with ciprofloxacin on human leukemia KG1-a stem-like cells in the presence and absence of insulin.

BACKGROUND: Acute Myeloid Leukemia (AML) is a fast-developing invading cancer that impacts the blood and bone marrow, marked by the rapid proliferation of abnormal white blood cells. Chemotherapeutic agents, a primary treatment for AML, encounter clinical limitations such as poor solubility and low bioavailability. Previous studies have highlighted antibiotics as effective in inducing cancer cell death and potentially preventing metastasis. Besides, insulin is known to activate the PI3K/Akt pathway, often disrupted in cancers, leading to enhanced cell survival and resistance to apoptosis. In light of the above-mentioned points, we examined the anti-cancer impact of antibiotics Ciprofloxacin (CP) and Salinomycin (SAL) and their combination on KG1-a cells in the presence and absence of insulin. METHODS: This was accomplished by exposing KG1-a cells to different doses of CP and SAL alone, in combination, and with or without insulin for 24-72 h. Cell viability was evaluated using the MTT assay. Besides, apoptotic effects were examined using Hoechst staining and Annexin-V/PI flow cytometry. The expression levels of Bax, p53, BIRC5, Akt, PTEN, and FOXO1 were analyzed through Real-Time PCR. RESULTS: CP and SAL demonstrated cytotoxic and notable pro-apoptotic impact on KG1-a cells by upregulating Bax and p53 and downregulating BIRC5, leading to G0/G1 cell cycle arrest and prevention of the PI3K-Akt signaling pathway. Our findings demonstrated that combination of CP and SAL promote apoptosis in the KG1-a cell line by down-regulating BIRC5 and Akt, as well as up-regulating Bax, p53, PTEN, and FOXO1. Additionally, the findings strongly indicated that insulin effectively mitigates apoptosis by enhancing Akt expression and reducing FOXO1 and PTEN gene expression in the cells treated with CP and SAL. CONCLUSION: Our findings showed that the combined treatment of CP and SAL exhibit a strong anti-cancer effect on leukemia KG1-a cells. Moreover, it was discovered that the PI3K-Akt signaling can be a promising target in leukemia treatment particularly in hyperinsulinemia condition.

The roles of phosphorylation of signaling proteins in the prognosis of acute myeloid leukemia.

Signaling pathways of Retinoblastoma (Rb) protein, Akt-kinase, and Erk-kinase (extracellular signal-regulated kinase) have an important role in the pathogenesis of acute myeloid leukemia. Constitutive activation of these proteins by phosphorylation contributes to cell survival by regulation of cell cycle, proliferation and proapoptotic signaling processes. According to previous data phosphorylated forms of these proteins represent a worse outcome for cancer patients. We investigated the presence of phosphorylated Rb (P-Rb), Akt (P-Akt) and Erk (P-Erk) proteins by Western blot technique using phospho-specific antibodies in bone marrow or peripheral blood samples of 69 AML patients, 36 patients with myelodysplastic syndrome (MDS) and 10 healthy volunteers. Expression level of PTEN (Phosphatase and tensin homolog) and PHLPP (PH domain and leucine-rich repeat Protein Phosphatase) phosphatases, the negative regulators of Akt kinase pathway were also examined. We tested the effect of these proteins on survival and on the correlation with known prognostic features in AML. We found 46.3% of AML patients had detectable P-Rb, 34.7% had P-Akt and 28.9% had P-Erk protein. 66.1% of patients expressing PTEN, 38.9% PHLPP, 37.2% both PTEN and PHLPP and 32.2% neither PTEN nor PHLPP phosphatases. Compared to nucleophosmin mutation (NPMc) negative samples P-Erk was significantly less in nucleophosmin mutated patients, P-Rb was significantly less in patients' group with more than 30 G/L peripheral leukocyte count by diagnosis. PHLPP was significantly present in FAB type M5. The expression of P-Rb represented significant better overall survival (OS), while P-Akt represented significantly worse event-free survival (EFS) in unfavorable cytogenetics patients. The presence of both PHLPP and PTEN phosphatases contributes to better OS and EFS, although the differences were not statistically significant. We confirmed significant positive correlation between P-Akt and PHLPP. Assessing the phosphorylation of Rb, Akt and Erk may define a subgroup of AML patients who would benefit especially from new targeted treatment options complemented the standard chemotherapy, and it may contribute to monitoring remission, relapse or progression of AML.

HOXA9 Regulome and Pharmacological Interventions in Leukemia.

HOXA9, an important transcription factor (TF) in hematopoiesis, is aberrantly expressed in numerous cases of both acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL) and is a strong indicator of poor prognosis in patients. HOXA9 is a proto-oncogene which is both sufficient and necessary for leukemia transformation. HOXA9 expression in leukemia correlates with patient survival outcomes and response to therapy. Chromosomal transformations (such as NUP98-HOXA9), mutations, epigenetic dysregulation (e.g., MLL- MENIN -LEDGF complex or DOT1L/KMT4), transcription factors (such as USF1/USF2), and noncoding RNA (such as HOTTIP and HOTAIR) regulate HOXA9 mRNA and protein during leukemia. HOXA9 regulates survival, self-renewal, and progenitor cell cycle through several of its downstream target TFs including LMO2, antiapoptotic BCL2, SOX4, and receptor tyrosine kinase FLT3 and STAT5. This dynamic and multilayered HOXA9 regulome provides new therapeutic opportunities, including inhibitors targeting DOT1L/KMT4, MENIN, NPM1, and ENL proteins. Recent findings also suggest that HOXA9 maintains leukemia by actively repressing myeloid differentiation genes. This chapter summarizes the recent advances understanding biochemical mechanisms underlying HOXA9-mediated leukemogenesis, the clinical significance of its abnormal expression, and pharmacological approaches to treat HOXA9-driven leukemia.

Epigenetic-based differentiation therapy for Acute Myeloid Leukemia.

Despite the development of novel therapies for acute myeloid leukemia, outcomes remain poor for most patients, and therapeutic improvements are an urgent unmet need. Although treatment regimens promoting differentiation have succeeded in the treatment of acute promyelocytic leukemia, their role in other acute myeloid leukemia subtypes needs to be explored. Here we identify and characterize two lysine deacetylase inhibitors, CM-444 and CM-1758, exhibiting the capacity to promote myeloid differentiation in all acute myeloid leukemia subtypes at low non-cytotoxic doses, unlike other commercial histone deacetylase inhibitors. Analyzing the acetylome after CM-444 and CM-1758 treatment reveals modulation of non-histone proteins involved in the enhancer-promoter chromatin regulatory complex, including bromodomain proteins. This acetylation is essential for enhancing the expression of key transcription factors directly involved in the differentiation therapy induced by CM-444/CM-1758 in acute myeloid leukemia. In summary, these compounds may represent effective differentiation-based therapeutic agents across acute myeloid leukemia subtypes with a potential mechanism for the treatment of acute myeloid leukemia.

A novel LGALS1-depended and immune-associated fatty acid metabolism risk model in acute myeloid leukemia stem cells.

Leukemia stem cells (LSCs) are recognized as the root cause of leukemia initiation, relapse, and drug resistance. Lipid species are highly abundant and essential component of human cells, which often changed in tumor microenvironment. LSCs remodel lipid metabolism to sustain the stemness. However, there is no useful lipid related biomarker has been approved for clinical practice in AML prediction and treatment. Here, we constructed and verified fatty acid metabolism-related risk score (LFMRS) model based on TCGA database via a series of bioinformatics analysis, univariate COX regression analysis, and multivariate COX regression analysis, and found that the LFMRS model could be an independent risk factor and predict the survival time of AML patients combined with age. Moreover, we revealed that Galectin-1 (LGALS1, the key gene of LFMRS) was highly expressed in LSCs and associated with poor prognosis of AML patients, and LGALS1 repression inhibited AML cell and LSC proliferation, enhanced cell apoptosis, and decreased lipid accumulation in vitro. LGALS1 repression curbed AML progression, lipid accumulation, and CD8+ T and NK cell counts in vivo. Our study sheds light on the roles of LFMRS (especially LGALS1) model in AML, and provides information that may help clinicians improve patient prognosis and develop personalized treatment regimens for AML.

DCAF15 control of cohesin dynamics sustains acute myeloid leukemia.

The CRL4-DCAF15 E3 ubiquitin ligase complex is targeted by the aryl-sulfonamide molecular glues, leading to neo-substrate recruitment, ubiquitination, and proteasomal degradation. However, the physiological function of DCAF15 remains unknown. Using a domain-focused genetic screening approach, we reveal DCAF15 as an acute myeloid leukemia (AML)-biased dependency. Loss of DCAF15 results in suppression of AML through compromised replication fork integrity and consequent accumulation of DNA damage. Accordingly, DCAF15 loss sensitizes AML to replication stress-inducing therapeutics. Mechanistically, we discover that DCAF15 directly interacts with the SMC1A protein of the cohesin complex and destabilizes the cohesin regulatory factors PDS5A and CDCA5. Loss of PDS5A and CDCA5 removal precludes cohesin acetylation on chromatin, resulting in uncontrolled chromatin loop extrusion, defective DNA replication, and apoptosis. Collectively, our findings uncover an endogenous, cell autonomous function of DCAF15 in sustaining AML proliferation through post-translational control of cohesin dynamics.

MYB as a Critical Transcription Factor and Potential Therapeutic Target in AML.

Myb was identified over four decades ago as the transforming component of acute leukemia viruses in chickens. Since then it has become increasingly apparent that dysregulated MYB activity characterizes many blood cancers, including acute myeloid leukemia, and that it represents the most "addictive" oncoprotein in many, if not all, such diseases. As a consequence of this tumor-specific dependency for MYB, it has become a major focus of efforts to develop specific antileukemia drugs. Much attention is being given to ways to interrupt the interaction between MYB and cooperating factors, in particular EP300/KAT3B and CBP/KAT3A. Aside from candidates identified through screening of small molecules, the most exciting prospect for novel drugs seems to be the design of peptide mimetics that interfere directly at the interface between MYB and its cofactors. Such peptides combine a high degree of target specificity with good efficacy including minimal effects on normal hematopoietic cells.

Reverse Phase Proteomic Array Profiling of Asparagine Synthetase Expression in Newly Diagnosed Acute Myeloid Leukemia.

Asparaginase-based therapy is a cornerstone in acute lymphoblastic leukemia (ALL) treatment, capitalizing on the methylation status of the asparagine synthetase (ASNS) gene, which renders ALL cells reliant on extracellular asparagine. Contrastingly, ASNS expression in acute myeloid leukemia (AML) has not been thoroughly investigated, despite studies suggesting that AML with chromosome 7/7q deletions might have reduced ASNS levels. Here, we leverage reverse phase protein arrays to measure ASNS expression in 810 AML patients and assess its impact on outcomes. We find that AML with inv(16) has the lowest overall ASNS expression. While AML with deletion 7/7q had ASNS levels slightly lower than those of AML without deletion 7/7q, this observation was not significant. Low ASNS expression correlated with improved overall survival (46 versus 54 weeks, respectively, p = 0.011), whereas higher ASNS levels were associated with better response to venetoclax-based therapy. Protein correlation analysis demonstrated association between ASNS and proteins involved in methylation and DNA repair. In conclusion, while ASNS expression was not lower in patients with deletion 7/7q as initially predicted, ASNS levels were highly variable across AML patients. Further studies are needed to assess whether patients with low ASNS expression are susceptible to asparaginase-based therapy due to their inability to augment compensatory ASNS expression upon asparagine depletion.

A MOZ-TIF2 leukemia mouse model displays KAT6-dependent H3K23 propionylation and overexpression of a set of active developmental genes.

Aberrant regulation of chromatin modifiers is a common occurrence across many cancer types, and a key priority is to determine how specific alterations of these proteins, often enzymes, can be targeted therapeutically. MOZ, a histone acyltransferase, is recurrently fused to coactivators CBP, p300, and TIF2 in cases of acute myeloid leukemia (AML). Using either pharmacological inhibition or targeted protein degradation in a mouse model for MOZ-TIF2-driven leukemia, we show that KAT6 (MOZ/MORF) enzymatic activity and the MOZ-TIF2 protein are necessary for indefinite proliferation in cell culture. MOZ-TIF2 directly regulates a small subset of genes encoding developmental transcription factors, augmenting their high expression. Furthermore, transcription levels in MOZ-TIF2 cells positively correlate with enrichment of histone H3 propionylation at lysine 23 (H3K23pr), a recently appreciated histone acylation associated with gene activation. Unexpectedly, we also show that MOZ-TIF2 and MLL-AF9 regulate transcription of unique gene sets, and their cellular models exhibit distinct sensitivities to multiple small-molecule inhibitors directed against AML pathways. This is despite the shared genetic pathways of wild-type MOZ and MLL. Overall, our data provide insight into how aberrant regulation of MOZ contributes to leukemogenesis. We anticipate that these experiments will inform future work identifying targeted therapies in the treatment of AML and other diseases involving MOZ-induced transcriptional dysregulation.

The potential role of renin angiotensin system in acute leukemia: a narrative review.

Acute leukemias (ALs) are the most common cancers in pediatric population. There are two types of ALs: acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML). Some studies suggest that the Renin Angiotensin System (RAS) has a role in ALs. RAS signaling modulates, directly and indirectly, cellular activity in different cancers, affecting tumor cells and angiogenesis. Our review aimed to summarize the role of RAS in ALs and to explore future perspectives for the treatment of these hematological malignancies by modulating RAS molecules. The database including Pubmed, Scopus, Cochrane Library, and Scielo were searched to find articles about RAS molecules in ALL and in pediatric patients. The search terms were "RAS", "Acute Leukemia", "ALL", "Angiotensin-(1-7)", "Pediatric", "Cancer", "Angiotensin II", "AML". In the bone marrow, RAS has been found to play a key role in blood cell formation, affecting several processes including apoptosis, cell proliferation, mobilization, intracellular signaling, angiogenesis, fibrosis, and inflammation. Local tissue RAS modulates tumor growth and metastasis through autocrine and paracrine actions. RAS mainly acts via two molecules, Angiotensin II (Ang II) and Angiotensin (1-7) [Ang-(1-7)]. While Ang II promotes tumor cell growth and stimulates angiogenesis, Ang-(1-7) inhibits the proliferation of neoplastic cells and the angiogenesis, suggesting a potential therapeutic role of this molecule in ALL. The interaction between ALs and RAS reveals a complex network of molecules that can affect the hematopoiesis and the development of hematological cancers. Understanding these interactions could pave the way for innovative therapeutic approaches targeting RAS components.

Monocytic Differentiation in Acute Myeloid Leukemia Cells: Diagnostic Criteria, Biological Heterogeneity, Mitochondrial Metabolism, Resistance to and Induction by Targeted Therapies.

We review the importance of monocytic differentiation and differentiation induction in non-APL (acute promyelocytic leukemia) variants of acute myeloid leukemia (AML), a malignancy characterized by proliferation of immature myeloid cells. Even though the cellular differentiation block is a fundamental characteristic, the AML cells can show limited signs of differentiation. According to the French-American-British (FAB-M4/M5 subset) and the World Health Organization (WHO) 2016 classifications, monocytic differentiation is characterized by morphological signs and the expression of specific molecular markers involved in cellular communication and adhesion. Furthermore, monocytic FAB-M4/M5 patients are heterogeneous with regards to cytogenetic and molecular genetic abnormalities, and monocytic differentiation does not have any major prognostic impact for these patients when receiving conventional intensive cytotoxic therapy. In contrast, FAB-M4/M5 patients have decreased susceptibility to the Bcl-2 inhibitor venetoclax, and this seems to be due to common molecular characteristics involving mitochondrial regulation of the cellular metabolism and survival, including decreased dependency on Bcl-2 compared to other AML patients. Thus, the susceptibility to Bcl-2 inhibition does not only depend on general resistance/susceptibility mechanisms known from conventional AML therapy but also specific mechanisms involving the molecular target itself or the molecular context of the target. AML cell differentiation status is also associated with susceptibility to other targeted therapies (e.g., CDK2/4/6 and bromodomain inhibition), and differentiation induction seems to be a part of the antileukemic effect for several targeted anti-AML therapies. Differentiation-associated molecular mechanisms may thus become important in the future implementation of targeted therapies in human AML.

Orthogonal proteogenomic analysis identifies the druggable PA2G4-MYC axis in 3q26 AML.

The overexpression of the ecotropic viral integration site-1 gene (EVI1/MECOM) marks the most lethal acute myeloid leukemia (AML) subgroup carrying chromosome 3q26 abnormalities. By taking advantage of the intersectionality of high-throughput cell-based and gene expression screens selective and pan-histone deacetylase inhibitors (HDACis) emerge as potent repressors of EVI1. To understand the mechanism driving on-target anti-leukemia activity of this compound class, here we dissect the expression dynamics of the bone marrow leukemia cells of patients treated with HDACi and reconstitute the EVI1 chromatin-associated co-transcriptional complex merging on the role of proliferation-associated 2G4 (PA2G4) protein. PA2G4 overexpression rescues AML cells from the inhibitory effects of HDACis, while genetic and small molecule inhibition of PA2G4 abrogates EVI1 in 3q26 AML cells, including in patient-derived leukemia xenografts. This study positions PA2G4 at the crosstalk of the EVI1 leukemogenic signal for developing new therapeutics and urges the use of HDACis-based combination therapies in patients with 3q26 AML.

Discovery of a Promising CBP/p300 Degrader XYD129 for the Treatment of Acute Myeloid Leukemia.

The epigenetic target CREB (cyclic-AMP responsive element binding protein) binding protein (CBP) and its homologue p300 were promising therapeutic targets for the treatment of acute myeloid leukemia (AML). Herein, we report the design, synthesis, and evaluation of a class of CBP/p300 PROTAC degraders based on our previously reported highly potent and selective CBP/p300 inhibitor 5. Among the compounds synthesized, 11c (XYD129) demonstrated high potency and formed a ternary complex between CBP/p300 and CRBN (AlphaScreen). The compound effectively degraded CBP/p300 proteins and exhibited greater inhibition of growth in acute leukemia cell lines compared to its parent compound 5. Furthermore, 11c demonstrated significant inhibition of tumor growth in a MOLM-16 xenograft model (TGI = 60%) at tolerated dose schedules. Our findings suggest that 11c is a promising lead compound for the treatment of AML.

In silico predicted compound targeting the IQGAP1-GRD domain selectively inhibits growth of human acute myeloid leukemia.

Acute myeloid leukemia (AML) is fatal in the majority of adults. Identification of new therapeutic targets and their pharmacologic modulators are needed to improve outcomes. Previous studies had shown that immunization of rabbits with normal peripheral WBCs that had been incubated with fluorodinitrobenzene elicited high titer antibodies that bound to a spectrum of human leukemias. We report that proteomic analyses of immunoaffinity-purified lysates of primary AML cells showed enrichment of scaffolding protein IQGAP1. Immunohistochemistry and gene-expression analyses confirmed IQGAP1 mRNA overexpression in various cytogenetic subtypes of primary human AML compared to normal hematopoietic cells. shRNA knockdown of IQGAP1 blocked proliferation and clonogenicity of human leukemia cell-lines. To develop small molecules targeting IQGAP1 we performed in-silico screening of 212,966 compounds, selected 4 hits targeting the IQGAP1-GRD domain, and conducted SAR of the 'fittest hit' to identify UR778Br, a prototypical agent targeting IQGAP1. UR778Br inhibited proliferation, induced apoptosis, resulted in G2/M arrest, and inhibited colony formation by leukemia cell-lines and primary-AML while sparing normal marrow cells. UR778Br exhibited favorable ADME/T profiles and drug-likeness to treat AML. In summary, AML shows response to IQGAP1 inhibition, and UR778Br, identified through in-silico studies, selectively targeted AML cells while sparing normal marrow.