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Background: Acute myeloid leukaemia (AML) comprises a group of heterogeneous and aggressive haematological malignancies with unsatisfactory prognoses and limited treatment options. Treatments targeting B-cell lymphoma-2 (BCL-2) with venetoclax have been approved for patients with AML, and venetoclax-based drug combinations are becoming the standard of care for older patients unfit for intensive chemotherapy. However, the therapeutic duration of either single or combination strategies is limited, and the development of resistance seems inevitable. Therefore, more effective combination regimens are urgently needed. Methods: The efficacy of combination therapy with NL101, a SAHA-bendamustine hybrid, and venetoclax was evaluated in preclinical models of AML including established cell lines, primary blasts from patients, and animal models. RNA-sequencing and immunoblotting were used to explore the underlying mechanism. Results: NL101 significantly potentiated the activity of venetoclax in AML cell lines, as evidenced by the enhanced decrease in viability and induction of apoptosis. Mechanistically, the addition of NL101 to venetoclax decreased the stability of the antiapoptotic protein myeloid cell leukaemia-1 (MCL-1) by inhibiting ERK, thereby facilitating the release of BIM and triggering mitochondrial apoptosis. Moreover, the strong synergy between NL101 and venetoclax also relied on the downregulation of c-Myc via PI3K/Akt/GSK3β signalling. The combination of NL101 and venetoclax synergistically eliminated primary blasts from 10 AML patients and reduced the leukaemia burden in an MV4-11 cell-derived xenograft model. Conclusions: Our results encourage the pursuit of clinical trials of combined treatment with NL101 and venetoclax and provide a novel venetoclax-incorporating therapeutic strategy for AML. [ABSTRACT FROM AUTHOR]

Previous evidence has confirmed that branched-chain aminotransferase-1 (BCAT1), a key enzyme governing branched-chain amino acid (BCAA) metabolism, has a role in cancer aggression partly by restricting αKG levels and inhibiting the activities of the αKG-dependent enzyme family. The oncogenic role of BCAT1, however, was not fully elucidated in acute myeloid leukemia (AML). In this study, we investigated the clinical significance and biological insight of BCAT1 in AML. Using q-PCR, we analyzed BCAT1 mRNAs in bone marrow samples from 332 patients with newly diagnosed AML. High BCAT1 expression independently predicts poor prognosis in patients with AML. We also established BCAT1 knockout (KO)/over-expressing (OE) AML cell lines to explore the underlying mechanisms. We found that BCAT1 affects cell proliferation and modulates cell cycle, cell apoptosis, and DNA damage/repair process. Additionally, we demonstrated that BCAT1 regulates histone methylation by reducing intracellular αKG levels in AML cells. Moreover, high expression of BCAT1 enhances the sensitivity of AML cells to the Poly (ADP-ribose) polymerase (PARP) inhibitor both in vivo and in vitro. Our study has demonstrated that BCAT1 expression can serve as a reliable predictor for AML patients, and PARP inhibitor BMN673 can be used as an effective treatment strategy for patients with high BCAT1 expression. Key messages: High expression of BCAT1 is an independent risk factor for poor prognosis in patients with CN-AML. High BCAT1 expression in AML limits intracellular αKG levels, impairs αKG-dependent histone demethylase activity, and upregulates H3K9me3 levels. H3K9me3 inhibits ATM expression and blocks cellular DNA damage repair process. Increased sensitivity of BCAT1 high expression AML to PARP inhibitors may be used as an effective treatment strategy in AML patients. [ABSTRACT FROM AUTHOR]

Background: Recently, an increasing number of studies have suggested dual-specificity phosphatase 23 (DUSP23) is a critical factor in the development of diffuse connective tissue disease and may be a valuable biomarker for primary human cancers. However, there is a lack of comprehensive studies on the prognostic significance of DUSP23 expression in acute myeloid leukemia (AML). Methods: RNA sequencing data from The Cancer Genome Atlas (TCGA) (AML = 173), Genotype-Tissue Expression (GTEx) (healthy controls = 70) and GEO (AML = 461, healthy controls = 76) databases were used to compare DUSP23 expression between AML patients and healthy controls. The overall survival (OS) of DUSP23 in AML was evaluated using Kaplan-Meier Cox regression. Furthermore, univariate Cox regression and multivariate Cox regression analysis were used to determine whether DUSP23 was an independent prognostic factor for AML. We then verified the expression level and prognostic significance of DUSP23 in our cohort (AML = 128, healthy controls = 31). In addition, functional enrichment analysis of DUSP23-related DEGs was performed through gene set enrichment analysis (GSEA) and protein-protein interaction (PPI) network analysis. Results: The expression level of DUSP23 is significantly higher in AML patients than in healthy controls in TCGA, GTEx, GEO databases and our cohort. By multivariate analysis, high expression of DUSP23 is a poor prognostic indicator of OS in the TCGA database. Next, we verified the role of DUSP23 as an adverse prognostic biomarker in our cohort. Enrichment analysis of related genes showed that DUSP23 may regulate important signal pathways in hematological tumors including the MAPK pathways. It is suggested by the PPI network that DUSP23, along with IMP3, MRPL4, MRPS12, POLR2L, and ATP5F1D may play a role in the process of AML. Conclusion: The study demonstrated high expression of DUSP23 could serve as a poor independent prognostic biomarker in AML. [ABSTRACT FROM AUTHOR]

Bromodomain‐containing protein 4 (BRD4) inhibitors have been clinically developed to treat acute myeloid leukemia (AML), but their application is limited by the possibility of drug resistance, which is reportedly associated with the activation of the WNT/β‐catenin pathway. Meanwhile, homoharringtonine (HHT), a classic antileukemia drug, possibly inhibits the WNT/β‐catenin pathway. In this study, we attempted to combine a novel BRD4 inhibitor (ACC010) and HHT to explore their synergistic lethal effects in treating AML. Here, we found that co‐treatment with ACC010 and HHT synergistically inhibited cell proliferation, induced apoptosis, and arrested the cell cycle in FMS‐like tyrosine kinase 3‐internal tandem duplication (FLT3‐ITD)–positive AML cells in vitro, and significantly inhibiting AML progression in vivo. Mechanistically, ACC010 and HHT cooperatively downregulated MYC and inhibited FLT3 activation. Further, when HHT was added, ACC010‐resistant cells demonstrated a good synergy. We also extended our study to the mouse BaF3 cell line with FLT3‐inhibitor‐resistant FLT3‐ITD/tyrosine kinase domain mutations and AML cells without FLT3‐ITD. Collectively, our results suggested that the combination treatment of ACC010 and HHT might be a promising strategy for AML patients, especially those carrying FLT3‐ITD. [ABSTRACT FROM AUTHOR]

Introduction: Recent studies have suggested that CD300A was an oncogene in acute myeloid leukemia (AML) development. However, the clinical relevance and biological insight into CD300A expression in AML are still not well understood. The present study aimed to examine the expression characteristics of CD300A in AML and confirmed its clinical significance for AML. Methods: Quantification of the CD300A transcript was performed in 119 AML patients by real-time quantitative PCR in bone marrow blasts. The predictive significance of CD300A expression on the clinical outcomes of AML was assessed using overall survival (OS) and relapse-free survival (RFS). The published Cancer Genome Atlas (TCGA) data were used as an external validation for survival analysis and pathway analyses. Results: In comparison with monocytes from healthy peripheral blood cells, the expression levels of CD300A in AML cells were higher. Patients in the intermediate and adverse risk categories by WHO criteria (2018) had higher CD300A expression levels than those in the favorable risk category (p < 0.001). AML patients with high expression of CD300A had a higher early death rate (p = 0.029), lower complete remission rate (p = 0.042), higher death rate (p < 0.001) and relapse rate (p = 0.002), and shorter OS (p < 0.0001) and RFS (p < 0.0001). Through multivariable analysis, high CD300A expression in AML was also an independent poor prognostic factor. The CAMP and CGMP-PKG signaling pathways may be stimulated by increased CD300A expression levels, which may be important for the development of AML. Conclusions: The expression levels of CD300A were associated with risk stratification and the clinical relevance of AML. High CD300A expression may act as an independent adverse prognostic factor for OS and RFS in AML. [ABSTRACT FROM AUTHOR]

The transcription factor interferon regulatory factor 8 (IRF8), as a member of the IRF family, is essential for myeloid cell differentiation. However, the precise role of IRF8 in the pathogenesis of acute myeloid leukemia (AML) remains unknown. By using multivariate analysis, we discovered that high IRF8 expression was an independent poor predictor of overall survival (OS) in AML patients from our clinical follow-up study. The proliferation of three AML cell lines was significantly inhibited by shRNA-mediated knockdown of IRF8, owing to cell cycle S-phase arrest. Furthermore, we demonstrated that knocking down IRF8 could suppress the expression of CyclinA and CyclinB1, resulting in a shift in cell cycle distribution. Loss of IRF8 in AML cells decreased the expression of STAT3 and phosphor-STAT3 (pSTAT3), which are key factors in JAK/STAT signal pathway and are important for AML progression. Using a xenograft mouse model, we discovered the antiproliferative effect of losing IRF8 in vivo. In conclusion, this study found that IRF8 may play a prognostic factor and therapeutic target in AML. [ABSTRACT FROM AUTHOR]

Background: Identifying therapeutic targets and prognostic biomarkers significantly contributes to individualized treatment of acute myeloid leukemia (AML). Dihydropyrimidinase‐like 2 (DPYSL2) expression was decreased in homoharringtonine (HHT)‐resistant AML cells, which were established by our group. DPYSL2 plays an important role in axon growth and has oncogene effect in glioblastoma. However, little research has been conducted to investigate the function of DPYSL2 in AML pathogenesis. Methods: Auto‐docking was used to reveal the targeting relationship between HHT and DPYSL2. Overall survival (OS), event‐free survival (EFS), and relapse‐free survival (RFS) were used to evaluate the prognostic impact of DPYSL2 for AML. ShRNA was used to knockdown the expression of SPATS2L. Apoptosis was assessed by flow cytometry. In vivo growth and survival were assessed using a xenotransplantation mice model. RNA sequencing was performed to elucidate the molecular mechanisms underlying the role of SPATS2L in AML and were confirmed by Western blot. Results: We found DPYSL2 was the target of HHT. Next, we found AML cell lines and patients had higher DPYSL2 expression levels than the normal samples. Further multivariate analysis demonstrated that high DPYSL2 expression was an independent poor prognostic factor for OS, EFS, and RFS in AML. Inhibition of DPYSL2 expression suppressed cell growth, induced apoptosis in AML cell lines, and prolonged the survival of AML xenograft NCG mice. Through RNA‐seq analysis from TCGA and our data, the JAK2/STAT3/STAT5‐PI3K P85/AKT/GSK3b axis was thought to be the critical pathway in regulating DPYSL2 in AML development. Conclusions: We first time confirmed that DPYSL2 was a target of HHT and played an oncogene role in AML by regulating JAK/STAT signaling pathway. Therefore, DPYSL2 could serve as a novel prognostic marker and therapeutic target for AML treatment. [ABSTRACT FROM AUTHOR]

Acute myeloid leukemia (AML) is a group of hematological malignancies characterized by clonal proliferation of immature myeloid cells. Lipid rafts are highly organized membrane subdomains enriched in cholesterol, sphingolipids, and gangliosides and play roles in regulating apoptosis through subcellular redistribution. Flotillin1 (FLOT1) is a component and also a marker of lipid rafts and had been reported to be involved in the progression of cancers and played important roles in cell death. However, the role of FLOT1 in AML remains to be explored. In this study, we found that increased expression of FLOT1 was correlated with poor clinical outcome in AML patients. Knockdown of FLOT1 in AML cells not only promoted cell death in vitro but also inhibited malignant cells engraftment in vivo. Mechanically, FLOT1 knockdown triggered apoptosis and pyroptosis. FLOT1 overexpression promoted AML cell growth and apoptosis resistance. Our findings indicate that FLOT1 is a prognostic factor of AML and may be a potential target for AML treatment. [ABSTRACT FROM AUTHOR]

Background: Spermatogenesis associated serine rich 2 like (SPATS2L) was highly expressed in homoharringtonine (HHT) resistant acute myeloid leukemia (AML) cell lines. However, its role is little known in AML. The present study aimed to investigate the function of SPATS2L in AML pathogenesis and elucidate the underlying molecular mechanisms. Methods: Overall survival (OS), event-free survival (EFS), relapse-free survival (RFS) were used to evaluate the prognostic impact of SPATS2L for AML from TCGA database and ourcohort. ShRNA was used to knockdown the expression of SPATS2L. Apoptosis was assessed by flow cytometry. The changes of proteins were assessed by Western blot(WB). A xenotransplantation mice model was used to evaluate in vivo growth and survival. RNA sequencing was performed to elucidate the molecular mechanisms underlying the role of SPATS2L in AML. Results: SPATS2L expression increased with increasing resistance indexes(RI) in HHT-resistant cell lines we had constructed. Higher SPATS2L expression was observed in intermediate/high-risk patients than in favorable patients. Meanwhile, decreased SPATS2L expression was observed in AML patients achieving complete remission (CR). Multivariate analysis showed high SPATS2L expression was an independent poor predictor of OS, EFS, RFS in AML. SPATS2L knock down (KD) suppressed cell growth, induced apoptosis, and suppressed key proteins of JAK/STAT pathway, such as JAK2, STAT3, STAT5 in AML cells. Inhibiting SPATS2L expression markedly enhanced the pro-apoptotic effects of traditional chemotherapeutics (Ara-c, IDA, and HHT). Conclusions: High expression of SPATS2L is a poor prognostic factor in AML, and targeting SPATS2L may be a promising therapeutic strategy for AML patients. [ABSTRACT FROM AUTHOR]

Homoharringtonine- (HHT-) based HHT, aclarubicin, and cytarabine (HAA) induction regimen is the first-line therapy for nonelder acute myeloid leukemia (AML) patients in China. However, drug resistance is a new challenge, and little attention has been devoted to excavating resistant mechanisms. This study used the classic method to construct six HHT-resistant cell lines with a gradually increasing resistance index (RI) to discover HHT drug resistance mechanisms dynamically. After HHT resistance, the cell growth rate decreased, cell cycle delayed, and P-glycoprotein (p-gp, CD243) expression levels increased. Furthermore, we explored the changes in transcriptomics between HHT-sensitive and HHT-resistant cells using RNA-sequence. Through Kyoto Encyclopedia of Genes and Genomes (KEGG), Gene Ontology (GO), and hub gene analyses, we found that immune activity, especially G-protein coupled receptor (GPR) and related molecules, may mediate HHT resistance. Moreover, Calcitonin Receptor-Like (CALCRL) and G Protein Subunit Alpha I1 (GNAI1), which belong to GPRs, were stimulated in HHT-resistant cell strains in vitro and vivo, indicating that they may play a critical role in HHT resistance. In addition, these two genes have prognostic significance for AML patients. Taken together, we successfully constructed HHT-resistant cell lines with dynamic RIs and explored the resistance mechanisms, which will help identify new drugs for HHT-resistant AML patients. [ABSTRACT FROM AUTHOR]

Objective: Phospholipase D (PLD) is known to participate in several aspects of cellular processes including cell mitosis, migration, phagocytosis, and membrane vesicle trafficking. The role of PLD has been investigated in multiple cancers except hematologic malignances. Methods: We enrolled 291 patients with de novo acute myeloid leukemia (AML) and detected PLD1 mRNA expression levels of their bone marrow samples by quantitative real-time PCR (qRT-PCR). Clinical relevance of PLD1 was assessed using Kaplan–Meier analysis, univariate analysis, and multivariate analysis. Results: Compared to healthy donors, AML patients had higher mRNA levels of PLD1, which was significantly associated with FAB classification. Importantly, patients with low levels of PLD1 had impaired overall survival and event-free survival. Moreover, univariate and multivariate analyses confirmed that PLD1 expression was an independent prognostic factor for AML. Conclusion: PLD1 represented a useful diagnostic marker and prognostic factor for AML. [ABSTRACT FROM AUTHOR]

Inhibin-β A (INHBA) is a ligand of the transforming growth factor β superfamily and associated with tumorigenesis and tumor progression in solid tumors. In this study, we investigated the expression levels and clinical significance ofINHBAin acute myeloid leukemia (AML). The results showed that high expression ofINHBAwas significantly correlated with elderly age (>60 years) (p = .038), adverse cytogenetic risks (p = .034), negativeNPM1mutation (p = .016), positiveFLT3internal tandem duplications (p = .011), and low hemoglobin levels (<60 g/dL) (p = .04). Patients with high levels ofINHBAhad poor responses to therapies as indicated by lower complete remission rate (p = .004), higher early death rate (p = .018), and shorter relapse-free survival (p = .04) and overall survival (p = .003). Moreover, multivariate analysis showed that high expression ofINHBAwas an independent adverse prognostic factor for AML. Taken together, our study suggested that high expression ofINHBAwas an adverse prognostic factor forde novoAML. [ABSTRACT FROM AUTHOR]