Apoptosis In Acute Myeloid Leukemia Cells Research Articles

TRIM10 Is Downregulated in Acute Myeloid Leukemia and Plays a Tumor Suppressive Role via Regulating NF-κB Pathway.

Accumulating evidence suggests that members of the tripartite motif (TRIMs) family play a crucial role in the development and progression of hematological malignancy. Here, we explored the expression and potential role of TRIM10 in acute myeloid leukemia (AML). The expression levels of TRIM10 were investigated in AML patients and cell lines by RNA-seq, qRT-PCR and Western blotting analysis. Lentiviral infection was used to regulate the level of TRIM10 in AML cells. The effects of TRIM10 on apoptosis, drug sensitivity and proliferation of AML cells were evaluated by flow cytometry and cell-counting kit-8 (CCK-8) assay, as well as being assessed in a murine model. TRIM10 mRNA and protein expression was reduced in primary AML samples and AML cell lines in comparison to the normal controls and a human normal hematopoietic cell line, respectively. Moreover, overexpression of TRIM10 in HL60 and K562 cells inhibited AML cell proliferation and induced cell apoptosis. The nude mice study further confirmed that overexpression of TRIM10 blocked tumor growth and inhibited cell proliferation. In contrast, knockdown of TRIM10 in AML cells showed contrary results. Subsequent mechanistic studies demonstrated that knockdown of TRIM10 enhanced the expression of nuclear protein P65, which implied the activation of the NF-κB signal pathway. Consistently, overexpression of TRIM10 in AML cells showed a contrary result. These data indicated that inactivation of the NF-κB pathway is involved in TRIM10-mediated regulation in AML. TRIM10 expression can be de-repressed by a combination that targets both DNA methyltransferase and histone deacetylase. Our results strongly suggested that TRIM10 plays a tumor suppressive role in AML development associated with the NF-κB signal pathway and may be a potential target of epigenetic therapy against leukemia.

SLC25A1-associated prognostic signature predicts poor survival in acute myeloid leukemia patients.

Background: Acute myeloid leukemia (AML) is a heterogeneous malignant disease. SLC25A1, the gene encoding mitochondrial carrier subfamily of solute carrier proteins, was reported to be overexpressed in certain solid tumors. However, its expression and value as prognostic marker has not been assessed in AML. Methods: We retrieved RNA profile and corresponding clinical data of AML patients from the Beat AML, TCGA, and TARGET databases (TARGET_AML). Patients in the TCGA cohort were well-grouped into two group based on SLC25A1 and differentially expressed genes were determined between the SLC25A1 high and low group. The expression of SLC25A1 was validated with clinical samples. The survival and apoptosis of two AML cell lines were analyzed with SLC25A1 inhibitor (CTPI-2) treatment. Cox and the least absolute shrinkage and selection operator (LASSO) regression analyses were applied to Beat AML database to identify SLC25A1-associated genes for the construction of a prognostic risk-scoring model. Survival analysis was performed by Kaplan-Meier and receiver operator characteristic curves. Results: Our analysis revealed that high expressed level of SLC25A1 in AML patients correlates with unfavorable prognosis. Moreover, SLC25A1 expression was positively associated with metabolism activity. We further demonstrated that the inhibition of SLC25A1 could inhibit the proliferation and increase the apoptosis of AML cells. In addition, a panel of SLC25A1-associated genes, was identified to construct a prognostic risk-scoring model. This SLC25A1-associated prognostic signature (SPS) is an independent risk factor with high area under curve (AUC) values of receiver operating characteristic (ROC) curves. A high SPS in leukemia patients is associated with poor survival. A Prognostic nomogram including the SPS and other clinical parameters, was constructed and its predictive efficiency was confirmed. Conclusion: We have successfully established a SPS prognostic model that predict outcome and risk stratification in AML. This risk model can be used as an independent biomarker to assess prognosis of AML.

LINC00504 promotes the progression of acute myeloid leukemia by targeting MDM2.

Acute myeloid leukemia (AML) is a highly heterogeneous hematopoietic malignant tumor, accompanied by the abnormal cloning of myeloid hematopoietic stem cells, little is known about its etiological role and pathogenesis. We aimed to explore the effect and regulatory mechanism of LINC00504 on the malignant phenotypes of AML cells. In this study, LINC00504 levels in AML tissues or cells were ascertained by PCR. RNA pull-down and RIP assays were conducted to verify the combination of LINC00504 and MDM2. Cell proliferation was detected by CCK-8 and BrdU assays, apoptosis was checked by flow cytometry, and glycolytic metabolism levels were detected by ELISA analysis. The expressions of MDM2, Ki-67, HK2, cleaved caspase-3, and p53 were detected by western blotting and immunohistochemistry. A xenograft tumor model was used to detect the role of LINC00504 in vivo. Results showed that LINC00504 was highly expressed in AML and its high expression was related to clinicopathological features in AML patients. LINC00504 knockdown significantly inhibited the proliferation and glycolysis, while inducing apoptosis of AML cells. Meanwhile, LINC00504 downregulation also exerted a significant alleviating effect on AML cell growth in vivo. In addition, LINC00504 could bind to MDM2 protein and positively regulate its expression. Overexpression of LINC00504 promoted the malignant phenotypes of AML cells and partially reversed the inhibitory effects of LINC00504 knockdown on AML progression. In conclusion, LINC00504 facilitated AML cell proliferation and suppressed apoptosis through upregulating MDM2 expression, suggesting that LINC00504 may serve as a prognostic marker and therapeutic target in patients with AML.

HIVEP3 as a potential prognostic factor promotes the development of acute myeloid leukemia

Acute myeloid leukemia (AML) is a common malignancy worldwide. Human immune deficiency virus type 1 enhancer-binding protein 3 (HIVEP3) was verified to play a vital role in types of cancers. However, the functional role of HIVEP3 in AML was rarely reported. In this study, CCK-8, colony formation assay, flow cytometry, and Trans-well chamber experiments were applied for detecting cell proliferation, apoptosis, and invasion in AML cells. The expression of proteins related to TGF-β/Smad signaling pathway was determined by western blot. Our data showed that the expression level of HIVEP3 was closely related to the risk classification and prognosis of AML patients. Moreover, HIVEP3 was highly expressed in AML patients and cells. Knockdown of HIVEP3 significantly repressed cell proliferation invasion, and enhanced cell apoptosis in HL-60 and THP-1 cells. In addition, HIVEP3 donwreglation could inhibit the TGF-β/Smad signaling pathway. TGF-β overexpression could reverse the inhibition effects of HIVEP3 knockdown on AML development and the TGF-β/Smad signaling pathway. These findings indicated that HIVEP3 contributed to the progression of AML via regulating the TGF-β/Smad signaling pathway and had a prognostic value for AML.

GSK3 inhibitor suppresses cell growth and metabolic process in FLT3-ITD leukemia cells

Glycogen Synthase Kinase-3 (GSK-3) was recently implicated in the dysregulated biology of acute myeloid leukemia (AML). Low concentrations of GSK-3 inhibitors, SB216763 and BIO, suppressed the proliferation of AML cells with FLT3-ITD as early as 24 h after treatment. BIO was used in subsequent assays since it exhibited higher inhibitory effects than SB216763. BIO-induced G1 cell cycle arrest by regulating the expression of cyclin D2 and p21 in MV4-11 cells, and promoted apoptosis by regulating the cleaved-caspase3 signaling pathways. In vivo assays demonstrated that BIO suppressed tumor growth, while metabolomics assay showed that BIO reduced the levels of ATP and pyruvate in MV4-11 cells suggesting that it inhibited glycolysis. BIO markedly suppressed cell growth and induced apoptosis of AML cells with FLT3-ITD by partially inhibiting glycolysis, suggesting that BIO may be a promising therapeutic candidate for AML.

Effect of Berbamine Combined with Ibrutinib on the Proliferation and Apoptosis of Acute Myeloid Leukemia Cells

To investigate the effects of the combination of berbamine (BBM) and ibrutinib on the proliferation and apoptosis of acute myeloid leukemia (AML) cells and the mechanism of combined action. The AML cell lines were treated with BBM, ibrutinib and the combination of the two drugs respectively, CCK-8 method was used to detect the cell proliferation inhibition rate of each group and calculate the combination index (CI). The cell apoptosis in each group was detected by flow cytometry. Western blot was used to determine the expression of related proteins in each group. The cell viability in the combination group was significantly reduced, and the CI value of ED50/ED75/ED90<1. The expression of apoptotic related protein in the combination group was significantly up-regulated, while the expression of p-BTK, p-AKT, CREB, GSK3β and BCL-XL were significantly down-regulated. BBM and ibrutinib can synergistically inhibit the proliferation of AML cells and promote the apoptosis of AML cells. BBM and ibrutinib may play a synergistic effect through the p-BTK/p-AKT/CREB and GSK3β/BCL-XL signaling pathways.

Heterogeneity of Patient-Derived Acute Myeloid Leukemia Cells Subjected to SYK In Vitro Inhibition

Acute myeloid leukemia (AML) is an aggressive hematological malignancy with a dismal prognosis. The cytoplasmic spleen tyrosine kinase (SYK) is highly expressed by hematopoietic cells and has emerged as a potential therapeutic target. In this study, we evaluated the in vitro antileukemic effects of five SYK inhibitors, fostamatinib, entospletinib, cerdulatinib, TAK-659, and RO9021, in a consecutive AML patient cohort. All inhibitors demonstrated a concentration-dependent antiproliferative effect, although there was considerable heterogeneity among patients. For fostamatinib and TAK-659, the antiproliferative effects were significantly higher in FLT3 mutated patients compared to nonmutated patients. Fostamatinib, entospletinib, TAK-659, and RO9021 induced significant apoptosis in primary AML cells, although the proapoptotic effects of the SYK inhibitors were less pronounced than the antiproliferative effects. Finally, most of the SYK inhibitors caused a significant decrease in the release of cytokines and chemokines from primary AML cells, indicating a potent inhibitory effect on the release of these leukemic signaling molecules. We concluded that the SYK inhibitors had antileukemic effects in AML, although larger studies are strongly needed to identify which patient subsets will benefit most from such a treatment.

EBF1 Promotes Cell Proliferation, Migration and Inhibits Cell Apoptosis in AML

Background: Multiple studies reported that EBF1 played important roles in types of cancers. However, the potential molecular regulatory mechanism of EBF1 in acute myeloid leukemia (AML) remains to be further defined. In this study, we aimed to clarify the role and potential mechanism of EBF1 in AML. Method: The expression levels of EBF1 were assessed in AML patients and cell lines by RT-qPCR and western blots. The expression of EBF1 was up-regulated or knocked down in AML cell lines by lentivirus mediated overexpression and RNA interference. CCK-8, flow cytometry and trans well assays were used to analyze the effect of EBF1 on cell proliferation, cycle, apoptosis and migration. Results: The level of EBF1 expression was up-regulated in newly diagnosed AML patients and cell lines. The EBF1 gene expression significantly reduced in CR patients and significantly increased in relapsed patients as compared to newly diagnosed AML patients (both P <0.001). EBF1 knockdown repressed cell proliferation, migration, and induced cell apoptosis and cell cycle G0/G1 inhibition in AML cells. EBF1 overexpression promoted the malignancy of AML cells. Conclusion: Our findings manifested that EBF1 was remarkably upregulated in AML and downregulation of EBF1 repressed the malignant behaviors of AML cells, which would provide a new insight for the treatment of AML.

Combination of the Kdm-Family Inhibitor, Jib-04, Improves Response to Acute Myeloid Leukemia Cells to Venetoclax

Background: Acute Myeloid Leukemia (AML) is a heterogeneous hematological malignancy with a 5-year survival rate of about 30% in adults with AML. While over the prior several decades, the standard of care treatment for AML changed very little, a number of novel targeted therapies have emerged in recent years. Promising results from clinical trials with the BCL2-specific inhibitor, Venetoclax, in combination with hypomethylating agents (HMA) or low-dose cytarabine for AML treatment have generated enthusiasm in the field. However, data from a phase II trial indicated a 30% failure rate after Venetoclax+HMA treatment of newly diagnosed patients, suggesting additional options are needed. Thus, we sought to explore alternative drug combinations that may enhance the efficacy of Venetoclax. JIB-04 is a potent small molecule inhibitor of multiple members of the histone lysine demethylase (KDM) 4, 5 and 6 families with KDM5A being the most sensitive. Expression levels of histone lysine-specific demethylases are higher in AML compared to normal bone marrow, suggesting they are potential targets for therapeutic intervention. Pharmacological inhibition or genetic knock down of KDM 4, 5 and 6 family members leads to reduced proliferation, cell cycle arrest, and increased apoptosis of AML cells of various subtypes. These preliminary findings compelled us to explore the anti-leukemic activity of JIB-04 alone and in combination with Venetoclax. Methods: We treated AML cell lines, patient AML blasts, and CD34+ cells from healthy donors with JIB-04, Venetoclax, or the combination for 72 hours in vitro. Apoptosis was quantified by AnnexinV/propidium iodide (PI) staining. Cell proliferation of AML cell lines treated with JIB-04 was evaluated using MTT assay and transcriptome profiling was done by RNA-Seq. NSG mice were injected with MOLM-13 cells and treated with JIB-04, Venetoclax or the combination for two weeks. For the knock-down (KD) of DDIT4 MOLM-13 cells were transduced with a shRNA and cells were treated with Venetoclax for 72h and analyzed for apoptosis. Results: Treatment of AML cell lines with low nanomolar doses (IC50 range from 8-60nM) of JIB-04 resulted in inhibition of proliferation and induction of apoptosis. In all AML cell lines tested, including AML cell lines with relative resistance to Venetoclax, the combination of JIB-04 with Venetoclax showed a strong synergistic effect. Moreover, patient AML blasts also showed a synergistic response to the drug combination compared to single-drug treatments (Figure 1a). In contrast, viability of normal CD34+ hematopoietic cells was not affected by JIB-04 treatment even up to a dose of 100nM that leads to apoptosis in AML cells, indicating a broad therapeutic window. The combination treatment of NSG mice injected with MOLM-13 cells resulted in reduced engraftment of huCD45+ cells compared to the single treatments in the blood, bone marrow and spleen. RNA sequencing of AML-OCI3 and MOLM-13 cells treated with JIB-04 revealed regulation of genes related to the mTOR pathway, stress response or amino acid metabolism, indicating possible mechanisms affecting proliferation and apoptosis. DDIT4 (REDD1), a regulator of the mTOR pathway, was downregulated after JIB-04 treatment in both cell lines. KD of DDIT4 in MOLM-13 cells resulted in increased sensitivity to Venetoclax (Figure 1b). Summary/Conclusion: While the epigenetic inhibitor JIB-04 alone shows modest anti-leukemic effect, this study highlights the potential therapeutic benefit of combining JIB-04 and Venetoclax in AML. The analysis of transcriptomic changes after JIB-04 treatment identified the mTOR pathway regulator DDIT4 as a likely mediator of the sensitization of AML cells to Venetoclax. High DDIT4 expression is associated with a worse outcome in AML making it an attractive therapeutic target for AML, especially in combination with Venetoclax. Our result would suggest this drug combination as a possible treatment option for AML patients. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Therapeutic inhibition of PPARα-HIF1α-PGK1 signaling targets leukemia stem and progenitor cells in acute myeloid leukemia

Treatment of acute myeloid leukemia (AML) with chemotherapeutic agents fails to eliminate leukemia stem cells (LSC)，and thus patients remain at high risk for relapse. Therefore, the identification of agents that target LSC is an important consideration for the development of new therapies. Enhanced glycolysis in LSC contributes to the aggressiveness of AML, which is difficult to be targeted. In this study, we showed that targeting peroxisome-proliferator-activated receptor α (PPARα), a ligand-activated transcription factor by chiglitazar provided a promising therapeutic approach. We first identified that chiglitazar reduced cell viability and proliferation of the leukemia stem-like cells population in AML. Treatment with chiglitazar blocked the ubiquitination of PPARα and increased its expression, resulting in the inhibition of glucose metabolism and apoptosis of AML cells. Consistent with its anti-leukemia stem-like cells activity in vitro, chiglitazar treatment in vivo resulted in the significant killing of leukemia stem-like cells as demonstrated in AML patient-derived xenograft (PDX) models. Mechanistically, PPARα overexpression inhibited the expression and promoter activity of PGK1 through blocking HIF1-α interaction on the PGK1 promoter. Thus, we concluded that targeting PPARα may serve as a novel approach for enhancing stem and progenitor cells elimination in AML.

Targeting of G3BP2 Refines Prognosis and Synergizes with Venetoclax in Acute Myeloid Leukemia

Background: Identifying the molecular alterations that drive acute myeloid leukemia (AML) progression is critical for developing effective therapies. Currently, the B-cell lymphoma-2 (BCL2) selective inhibitor venetoclax revealed puissant survival benefits in the naive and refractory/relapse (R/R) acute myeloid leukemia (AML) patients during combination therapy. However, there are complex factors that limit the therapeutic efficacy of using venetoclax. Our study aimed to unravel the role and regulatory mechanisms of Ras-GTPase-activating protein SH3-domainbinding protein 2 (G3BP2) in AML, and to explore its potential interaction with venetoclax. Method: The mRNA levels of G3BP2 were detected in patients with AML and healthy donors using quantitative reverse transcription-PCR (RT-qPCR). Functional assays were performed to examine the effects of G3BP2 on cell proliferation and apoptosis in vitro. Gene set enrichment analysis (GSEA) was carried out to explore aberrantly activated pathways as G3BP2 increased. A Pearson correlation test was conducted to identify a correlation between G3BP2 and anti-apoptotic BCL-2 family proteins (BCL-2 and MCL-1). A small molecule (C108) that interfered with G3BP2 was used in combination with venetoclax to assess whether it yielded synergistic effects. We applied bioinformatics analysis, JASPAR database, western blot analysis, and actinomycin D-dependent mRNA stability assay to identify the transcription factor for MLC1. Results: G3BP2 was upregulated in AML patients, and its expression was negatively correlated with overall survival (OS). Knockdown of G3BP2 significantly inhibited cell proliferation and enhanced apoptosis in vitro. GSEA revealed the mTOR signaling was activated when G3BP2 was upregulated, and knockdown of G3BP2 abrogated the redundancy of pmTOR and pS6. Targeting G3BP2 with C108 synergized with venetoclax to induce apoptosis in primary AML cells and cell lines. Mechanistically, down-regulated G3BP2 led to increased ELF1 mRNA decay, thus impacting the decreased expression of MCL1 to overcome the inadequate venetoclax activity in AML cells. Conclusion: Our findings demonstrated that elevated G3BP2 might be responsible for the progress of AML. Moreover, G3BP2 could promote MCL1 transcription via ELF1, thus resulting in poor response to venetoclax in AML cells. These results provided a potential therapeutic target for venetoclax combination therapy. Keywords: Acute myeloid leukemia, G3BP2, Venetoclax, MCL1, ELF1 Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

PHF6 Maintains Acute Myeloid Leukemia Via Regulating NF-Κappab Signaling Pathway

Acute myeloid leukemia (AML) is a major hematopoietic malignancy characterized by the uncontrolled expansion of the immature myeloid cells in the hematopoietic system. Current chemotherapy regimens remain ineffective as assessed by low remission and 5-year-survival rate. Many efforts have been dedicated to decipher the molecular events underlying AML transformation. PHF6 is a conserved epigenetic regulator and has been found to be frequently altered in hematologic malignancies. Previous studies demonstrated that PHF6 plays a suppressive role in T-ALL leukemogenesis. However, the functional role(s) of PHF6 in AML initiation and progression remains unknown. Here in this study, we analyzed the mRNA expression of PHF6 in blood cells from healthy donors and leukemia cells from AML patients, and found that the PHF6 expression was significantly increased in AML cells when compared with that of normal PMNs (www.Bloodspot.com) (p < 0.05). Significantly, the average survival time of AML patients with high PHF6 expression was much shorter than that of AML patients with low PHF6 expression (p = 0.022). Overexpressing of PHF6 (PHF6 OE) in Kasumi-1 or K562 leukemia cell lines showed increased growth of Kasumi-1 and K562 cells, decreased apoptosis of Kasumi-1 cells. Additionally, we knocked down (KD) PHF6 expression in AML cells and CD34+ cord blood cells, and found that PHF6 KD significantly decreased the growth of Kasumi-1 and promoted cell apoptosis, while had little effects on apoptosis of CD34+ cord blood cells. These results suggested that PHF6 is required for the growth of myeloid leukemia cells but is dispensable for normal blood cells. To further evaluate the functional role of Phf6 in leukemogenesis in vivo, we generated Phf6 KO+RUNX1-ETO9a (RE9a) and Phf6 KO+MLL-AF9 (MA9) AML mice. We found the survival time of Phf6 KO+RE9a mice was significantly longer than that of WT Phf6+RE9a mice. The Phf6 KO+RE9a mice showed much milder disease phenotypes than WT Phf6+RE9a mice, including lower counts of GFP+ leukemia cells in the PB and BM, higher body weights, lower spleen and liver weights, and lower degree of extramedullary infiltration in spleen, liver, lung and brain. Extreme limiting dilution transplantation assays demonstrated a marked decrease in leukemia stem cell (LSC) activity in Phf6 KO+RE9a cells when compared with Phf6 WT+RE9a cells. Consistent with RE9a-induced AML mouse model, PHF6 deficiency impaired the self-renewal of LSCs and delayed the progression of MA9-induced AML, supporting a general oncogenic role of Phf6 in sustaining myeloid leukemia. To investigate the underlying molecular mechanisms of Phf6 in regulating AML development, we performed RNAseq to analyze the transcriptome programing changes associated with Phf6 deficiency in isogenic Phf6 WT+RE9a or Phf6 KO+RE9aAML cells. Gene set enrichment analysis (GSEA) showed up-regulation of apoptosis and down-regulation of NF-κB-regulated gene expressions in Phf6 KO+RE9a cells, suggesting that Phf6 depletion might promote AML cell apoptosis by blocking the NF-κB signaling. Immunocytochemistry studies showed that PHF6 depletion partially inhibited the nuclear translocation of p50. Co-immunoprecipitation experiments revealed that PHF6 directly bound to p50 in myeloid leukemia cells, suggesting that PHF6 might activate NF-κB signaling pathways by binding with p50 and maintaining the nuclear translocation of p50. To confirm this, we treated PHF6 OE AML cells with BAY11-7082 (a selective NF-κB inhibitor), and found BAY11-7082 significantly inhibited the growth of PHF6 OE Kasumi-1 cells in vitro. In summary, we revealed that PHF6 promoted RE9a- or MA9-induced AML progression in mice by activating NF-κB signaling pathway, and promoting P50 nuclear translocation. Our study thus defined a unique role for Phf6 in regulating NF-κB signaling pathway in AMLs, and potentially can be used as a therapeutic target for treating myeloid leukemia patients.

Over expression of ubiquitin-conjugating enzyme E2O in bone marrow mesenchymal stromal cells partially attenuates acute myeloid leukaemia progression.

Bone marrow mesenchymal stromal cells (BM-MSCs) are implicated in the pathogenesis of acute myeloid leukaemia (AML). However, due to the high heterogeneity of AML the mechanism underlying the cross-talk between MSCs and leukaemia cells is not well understood. We found that mixed-lineage leukaemia-AF9 (MLL-AF9)-induced AML mice-derived MSCs had higher proliferative viability compared to wild-type mice-derived MSCs with ubiquitin-conjugating enzyme E2O (Ube2o) down-regulation. After overexpression of UBE2O in AML-derived MSCs, the growth capacity of MSCs was reduced with nuclear factor kappa B subunit 1 (NF-κB) pathway deactivation. In vitro co-culture assay revealed that UBE2O-overexpression MSCs suppressed the proliferation and promoted apoptosis of AML cells by direct contact. In vivo results revealed that the leukaemia burden was reduced and the overall survival of AML mice was prolonged, with decreased dissemination of leukaemia cells in BM, spleen, liver and peripheral blood. Additionally, subcutaneous tumorigenesis revealed that tumour growth was also suppressed in the UBE2O-overexpression MSCs group. In conclusion, UBE2O was expressed at a low level in MLL-AF9-induced AML mice-derived MSCs. Overexpression of UBE2O in MSCs suppressed their proliferation through NF-κB pathway deactivation, which resulted in AML suppression. Our study provides a theoretical basis for a BM microenvironment-based therapeutic strategy to control disease progression.

From Serendipity to Rational Identification of the 5,6,7,8-Tetrahydrobenzo[4,5]thieno[2,3-d]pyrimidin-4(3H)-one Core as a New Chemotype of AKT1 Inhibitors for Acute Myeloid Leukemia.

Acute myeloid leukemia (AML) is a heterogeneous hematopoietic malignancy whose prognosis is globally poor. In more than 60% of AML patients, the PI3K/AKTs/mTOR signaling pathway is aberrantly activated because of oncogenic driver alterations and further enhanced by chemotherapy as a mechanism of drug resistance. Against this backdrop, very recently we have started a multidisciplinary research project focused on AKT1 as a pharmacological target to identify novel anti-AML agents. Indeed, the serendipitous finding of the in-house compound T187 as an AKT1 inhibitor has paved the way to the rational identification of new active small molecules, among which T126 has emerged as the most interesting compound with IC50 = 1.99 ± 0.11 μM, ligand efficiency of 0.35, and a clear effect at low micromolar concentrations on growth inhibition and induction of apoptosis in AML cells. The collected results together with preliminary SAR data strongly indicate that the 5,6,7,8-tetrahydrobenzo[4,5]thieno[2,3-d]pyrimidin-4(3H)-one derivative T126 is worthy of future biological experiments and medicinal chemistry efforts aimed at developing a novel chemical class of AKT1 inhibitors as anti-AML agents.

Co-targeting of HDAC, PI3K, and Bcl-2 results in metabolic and transcriptional reprogramming and decreased mitochondrial function in acute myeloid leukemia

Despite the recently approved new therapies, the clinical outcomes of acute myeloid leukemia (AML) patients remain disappointing, highlighting the need for novel therapies. Our lab has previously demonstrated the promising outlook for CUDC-907, a dual inhibitor of PI3K and HDAC, in combination with venetoclax (VEN), against AML both in vitro and in vivo at least partially through suppression of c-Myc. In this study, we further elucidated the mechanism of action of the combination in preclinical models of AML. We demonstrated that the combination significantly reduced primary AML cell engraftment in immunocompromised mice. RNA sequencing and metabolomics analyses revealed that the combination reduced the levels for mRNAs of key TCA cycle genes and metabolites in the TCA cycle, respectively. This was accompanied by a reduced oxygen consumption rate (OCR), demonstrating that the combination suppressed oxidative phosphorylation (OXPHOS). Metabolomics analyses revealed that a large number of metabolites upregulated in AraC-resistant AML cells could be downregulated by the combination. CUDC-907 synergized with VEN in inducing apoptosis in the AraC-resistant AML cells. In conclusion, the CUDC-907 and VEN combination induces metabolic and transcriptomic reprograming and suppression of OXPHOS in AML, which provides additional mechanisms underlying the synergy between the two agents.

BRD4 PROTAC degrader MZ1 exerts anticancer effects in acute myeloid leukemia by targeting c-Myc and ANP32B genes

ABSTRACT Acute myeloid leukemia (AML) is a highly cancerous and aggressive hematologic disease with elevated levels of drug resistance and relapse resulting in high mortality. Recently, bromodomains and extra-terminal (BET) protein inhibitors have been extensively researched in hematological tumors as potential anticancer agents. MZ1 is a novel BET inhibitor that mediates selective proteins degradation and suppression of tumor growth through proteolysis-targeting chimeras (PROTAC) technology. Accordingly, this study aimed to investigate the role and therapeutic potential of MZ1 in AML. In this study, we first identified that AML patients with high BRD4 expression had poor overall survival than those with low expression group. MZ1 inhibited AML cell growth and induced apoptosis and cycle arrest in vitro. MZ1 induced degradation of BRD4, BRD3 and BRD2 in AML cell strains. Additionally, MZ1 also initiated the cleavage of poly-ADP-ribose polymerase (PARP), which showed cytotoxic effects on NB4 (PML-RARa), K562 (BCR-ABL), Kasumi-1 (AML1-ETO), and MV4-11 (MLL-AF4) cell lines representing different molecular subtypes of AML. In AML mouse leukemia model, MZ1 significantly decreased leukemia cell growth and increased the mouse survival time. According to the RNA-sequencing analysis, MZ1 led to c-Myc and ANP32B genes significant downregulation in AML cell lines. Knockdown of ANP32B promoted AML cell apoptosis and inhibited cell growth. Overall, our data indicated that MZ1 had broad anti-cancer effects on AML cell lines with different molecular lesions, which might be exploited as a novel therapeutic strategy for AML patients.

Identification of Monobenzone as a Novel Potential Anti-Acute Myeloid Leukaemia Agent That Inhibits RNR and Suppresses Tumour Growth in Mouse Xenograft Model.

Simple SummaryThe clinical treatment of acute myeloid leukaemia is still dominated by chemotherapy. Clinically used anti-leukaemia drugs have shortcomings such as myelosuppression, toxicity and drug resistance. Therefore, the need to develop other chemotherapeutic drugs to meet more clinical needs is urgent. Ribonucleotide reductase (RNR) consists of a catalytic large subunit M1 (RRM1) and a regulatory small subunit M2 (RRM2), which provides dNTPs for DNA synthesis. The rapid proliferation of cancer cells requires large amounts of dNTPs. Therefore, the use of RNR inhibitors is a promising strategy for the clinical treatment of various malignancies. Monobenzone is an FDA-approved depigmenting agent for vitiligo patients. In this study, we demonstrate that monobenzone is a potent inhibitor of RNR enzyme activity by targeting RRM2 protein, and thus has significant anti-leukaemia efficacy in vitro and in vivo. This finding suggests that monobenzone has the potential to be optimized as a novel anti-AML therapeutic drug in the future. Acute myeloid leukaemia (AML) is one of the most common types of haematopoietic malignancy. Ribonucleotide reductase (RNR) is a key enzyme required for DNA synthesis and cell proliferation, and its small subunit RRM2 plays a key role for the enzymatic activity. We predicted monobenzone (MB) as a potential RRM2 target compound based on the crystal structure of RRM2. In vitro, MB inhibited recombinant RNR activity (IC50 = 0.25 μM). Microscale thermophoresis indicated that MB inhibited RNR activity by binding to RRM2. MB inhibited cell proliferation (MTT IC50 = 6–18 μM) and caused dose-dependent DNA synthesis inhibition, cell cycle arrest, and apoptosis in AML cells. The cell cycle arrest was reversed by the addition of deoxyribonucleoside triphosphates precursors, suggesting that RNR was the intracellular target of the compound. Moreover, MB overcame drug resistance to the common AML drugs cytarabine and doxorubicin, and treatment with the combination of MB and the Bcl-2 inhibitor ABT-737 exerted a synergistic inhibitory effect. Finally, the nude mice xenografts study indicated that MB administration produced a significant inhibitory effect on AML growth with relatively weak toxicity. Thus, we propose that MB has the potential as a novel anti-AML therapeutic agent in the future.

Chidamide works synergistically with Dasatinib by inducing cell-cycle arrest and apoptosis in acute myeloid leukemia cells.

This research aimed to explore whether Chidamide works synergistically with Dasatinib in the therapy of Acute myeloid leukemia (AML) and the potential molecular mechanism. The inhibition rate of the Dasatinib and Chidamide combination was significantly better than that of the single-drug application for HL-60 cells. The combination of Dasatinib and Chidamide significantly enhanced the Abnormal histone deacetylase (HDAC) inhibitory activity of Chidamide in Kasumi-1 and HL-60 cells. In the combined group, the proportion of S phase was significantly decreased, and the proportions of G2/M phase were significantly increased. The inhibitory rate of CD34+ CD38- HL-60 cells or Kasumi-1 cells was elevated when the cells were disposed with both Chidamide and Dasatinib. Dasatinib and Chidamide had synergistic antitumor effect. The combination with Dasatinib enhanced the HDAC inhibitory activity of Chidamide, promoted cell apoptosis and cell-cycle arrest of AML cells, and enhanced the inhibition of leukemia stem cell proliferation.

CircNFIX knockdown inhibited AML tumorigenicity by the miR-876-3p/TRIM31 axis

ABSTRACT Background Acute myeloid leukemia (AML) is one of the most common malignant myeloid diseases in adults with a dismal prognosis. We aimed to explore the effects of circNFIX on the proliferation and apoptosis of AML cells. Methods The expressions of circNFIX, miR-876-3p and tripartite motif (TRIM) 31 in the bone marrow specimens of AML patients and AML cell lines were detected by qRT-PCR or western blot. Cell proliferation was evaluated by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and 5-ethynyl-29-deoxyuridine (EdU) assays. Cell cycle and apoptosis were analyzed by flow cytometry. Western blot was used to detect protein expression. The relationship between miR-876-3p and circNFIX or TRIM31 was identified by dual-luciferase reporter assay or RNA pull-down assay. Results The expression level of circNFIX was significantly increased in the bone marrow samples of AML patients and AML cells when compared with normal controls. CircNFIX silencing inhibited AML cell proliferation and promoted apoptosis. Inhibition of miR-876-3p reversed the effect of circNFIX knockdown on AML cell progression. In addition, circNFIX indirectly regulated TRIM31 through miR-876-3p. Further, TRIM31 overexpression counteracted the effect of circNFIX silencing on AML cell proliferation and apoptosis. Conclusion CircNFIX knockdown could suppress the proliferation and induce the apoptosis of AML cells by targeting the miR-876-3p/TRIM31 axis.

MiR-342-3p Inhibits Acute Myeloid Leukemia Progression by Targeting SOX12.

Background It is well known that microRNAs (miRNAs) interfere with the progression of various human malignancies. This article is aimed at exploring the regulating role of miR-342-3p in acute myeloid leukemia (AML) and its mechanism. Methods We used the Gene Expression Omnibus (GEO) database to determine miR-342-3p differential expression patterns in AML patients' plasma and cells as well as healthy individuals' plasma and T cells. Quantitative real-time PCR and Western blotting were performed for plasma and cell miR-342-3p and SRY-related high-mobility-group box (SOX12) expression quantification, and cell counting kit-8 assay and flow cytometry were used for the determination of AML cell growth, cycle, and apoptosis. A dual-luciferase reporter gene assay was further carried out to identify the targeted association between miR-342-3p and SOX12 mRNA 3′UTR after prediction by a bioinformatics website. Pearson's correlation analysis was performed to analyze the connection between miR-342-3p and SOX12 expressions. The LinkedOmics database was utilized to explore the downstream pathways in which SOX12 was enriched. Results Evidently downregulated plasma miR-342-3p and markedly elevated SOX12 were observed in AML patients versus healthy individuals. miR-342-3p mimics suppressed AML cell growth, enhanced apoptosis, and induced G0/G1 phase arrest; conversely, enhanced capacity of AML cells to proliferate, suppressed apoptosis, and accelerated cell cycle were observed after treatment with miR-342-3p inhibitors. SOX12 was confirmed as miR-342-3p's target gene. Overexpressing or knocking down SOX12 reversed miR-342-3p's impacts on AML cell growth, apoptosis, and cycle. Upregulated SOX12 was positively related to DNA replication and RNA polymerase signaling pathways. Conclusion miR-342-3p affects apoptosis of AML cells and their ability to proliferate via targeted regulation of SOX12.