Apoptosis In Acute Myeloid Leukemia Cells Research Articles

PX-478 induces apoptosis in acute myeloid leukemia under hypoxia by inhibiting the PI3K/AKT/mTOR pathway through downregulation of GBE1

Acute myeloid leukemia (AML) is a highly heterogeneous hematologic malignancy characterized by limited therapeutic options and a pronounced tendency for relapse. PX-478, a novel inhibitor of hypoxia-inducible factor 1-alpha (HIF-1α), has demonstrated antitumor activity across various cancer models, but its specific role in AML remains unexplored. This study aimed to explore the potential target and mechanism of PX-478-induced AML cell apoptosis. First, PX-478 induced AML cell apoptosis in vitro under hypoxia via modulation of the Bcl-2 family and activation of the mitochondria-mediated caspase cascade, exhibiting a concentration-dependent effect. Additionally, in vivo administration of PX-478 led to notable inhibition of subcutaneous AML xenograft growth in mice, coupled with increased tumor cell apoptosis. RNA sequencing and cellular studies revealed downregulation of the PI3K/AKT/mTOR signaling pathway in PX-478-treated cells. Consistently, cellular studies also implicated PI3K/AKT/mTOR pathway in PX-478-induced AML cell apoptosis. Furthermore, by screening for RNA sequencing differential genes and subsequent experimental verification, Glycogen branching enzyme 1 (GBE1) may be involved in PX-478-induced apoptosis in AML cells. We found that inhibiting GBE1 expression in AML cells (siGBE1) led to downregulation of the PI3K/AKT/mTOR pathway and induced apoptosis. In experiments using AML cells with reduced GBE1 expression (shGBE1), PX-478 treatment did not further downregulate the pathway or enhance apoptosis. Re-expression of GBE1 in shGBE1 cells alleviated apoptosis and reduced PX-478- induced apoptosis and pathway downregulation. In conclusion, our findings provide convincing evidence that PX-478 induces apoptosis by inhibiting the PI3K/AKT/mTOR pathway through downregulation of GBE1 in AML cells

The prognostic significance of genetics in acute myeloid leukemia under venetoclax-based treatment.

Acute myeloid leukemia (AML) is the most prevalent hematologic malignancy in adults. In 2022, the European LeukemiaNet (ELN) has updated its prognostic system that incorporates cytogenetics and molecular genetics based on data from patients undergoing intensive chemotherapy (IC). Recently, a risk stratification framework has been established for hypomethylating agents (HMA)-based low-intensity treatment (LIT) to fill the gaps in stratification for this treatment modality, but this needs further refinement. Venetoclax (VEN), a BH3 mimetic, targets BCL-2 to modulate apoptosis and metabolism in AML cells. Its combination with HMA or low-dose cytarabine (LDAC) has been shown to enhance the response rates and prolong the survival outcomes of older or unfit patients with AML. In this review, we delved into the prognostic significance of FLT3-ITD and IDH mutations when used in combination with VEN and HMA, as well as in conjunction with their specific inhibitors. We also explored the role of VEN in NPM1-mutated AML and its efficacy in splicing factor mutations AML. Additionally, we examined the response rates and survival outcomes of CBF-AML when treated with a VEN-based regimen. Moving forward, it is imperative that risk stratification for LIT becomes more nuanced to better align with the requirements of personalized diagnosis and treatment strategies.

Gallic acid enhances GVL effects of T cells without exacerbating GVHD after haematopoietic stem cell transplantation.

Allogeneic haematopoietic stem cell transplantation (allo-HSCT) is an effective therapy for acute myeloid leukaemia (AML), predominantly due to its potent graft-versus-leukaemia (GVL) effect. However, leukaemia relapse remains a major obstacle to the success of allo-HSCT. In this study, we demonstrated that gallic acid (GA), a natural dietary compound, can enhance T-cell-mediated GVL effects both invitro and invivo. GA-treated T cells exhibited increased activation and elevated secretion of cytotoxic cytokines, leading to the apoptosis of AML cells in co-culture systems invitro. In a non-irradiated leukaemia mouse model, we showed that GA treatment prolonged the survival of leukaemic mice and reduced leukaemia cell infiltration. Further analysis revealed that GA treatment increased T-cell activation and tumour necrosis factor-α secretion. Moreover, integrated transcriptomic and proteomic analyses indicated that GA augments T-cell-mediated GVL effects through the activation of the MAPK and NF-κB pathways. Blocking these pathways individually diminished the protective effect of GA in AML model mice. Importantly, GA administration did not accelerate graft-versus-host disease (GVHD) progression in a mouse model. In conclusion, our study revealed that GA can enhance the GVL effects of T cells without exacerbating GVHD, offering insights into its potential to improve outcomes for patients after HSCT.

The Effects of RNF213 on the Proliferation and Apoptosis of Acute Myeloid Leukemia THP-1 Cells

To discover the relationship between the RNF213 gene and acute myeloid leukemia (AML), and explore the effect of RNF213 on the proliferation and apoptosis of THP-1 cells. Analyze the expression of RNF213 gene in AML and its relationship with prognosis through the GEPIA database. Collecting 30 AML patients and non-tumor hematological patients who went to the Affiliated Hospital of Zunyi Medical University from January 2017 to January 2022. RT-qPCR and Western blot were used to detect the expression levels of RNF213 mRNA and protein. Perform survival of patients was analysed by Kaplan-Meier. Meanwhile, the expression levels of RNF213 mRNA and protein were detected in AML cell lines (THP-1, OCI-AML2 ). CRISPR-Cas9 was used to knockdown the RNF213 gene in THP-1 cells; flow cytometry was used to detect apoptosis rate of cell. CCK-8 and colony formation assay were used to detect cell proliferation. Western blot was used to detect the expression level of Cleaved-Caspase 3 protein. Compared with the control group, the expression level of RNF213 in AML patients was significantly increased, and patients with high expression of RNF213 have a worse prgnosis. Higher expression level of RNF213 protein in THP-1 cells. After knocking down the RNF213 gene of THP-1 cells, cell proliferation was significantly reduced, and the apoptosis rate and expression of apoptosis related protein Cleared-Caspase3 were significantly increased. AML patients have high expression of RNF213 , and the prognosis of high expression patients is poor. The RNF213 gene affects AML cell proliferation and apoptosis, and may be a prognostic marker and potential therapeutic target for AML.

The Proteostasis Network is a Therapeutic Target in Acute Myeloid Leukemia.

Oncogenic growth places great strain and dependence on the proteostasis network. This has made proteostasis pathways attractive therapeutic targets in cancer, but efforts to drug these pathways have yielded disappointing clinical outcomes. One exception is proteasome inhibitors, which are approved for frontline treatment of multiple myeloma. However, proteasome inhibitors are largely ineffective for treatment of other cancers, including acute myeloid leukemia (AML), although reasons for these differences are unknown. Here, we determined that proteasome inhibitors are ineffective in AML due to inability to disrupt proteostasis. In response to proteasome inhibition, AML cells activated HSF1 and autophagy, two key stem cell proteostasis pathways, to prevent unfolded protein accumulation. Inactivation of HSF1 sensitized human AML cells to proteasome inhibition, marked by unfolded protein accumulation, activation of the PERK-mediated integrated stress response, severe reductions in protein synthesis, proliferation and cell survival, and significant slowing of disease progression and extension of survival in vivo . Similarly, combined autophagy and proteasome inhibition suppressed proliferation, synergistically killed AML cells, and significantly reduced AML burden and extended survival in vivo . Furthermore, autophagy and proteasome inhibition preferentially suppressed protein synthesis and induced apoptosis in primary patient AML cells, including AML stem/progenitor cells, without severely affecting normal hematopoietic stem/progenitor cells. Combined autophagy and proteasome inhibition also activated the integrated stress response, but surprisingly this occurred in a PKR-dependent manner. These studies unravel how proteostasis pathways are co-opted to promote AML growth, progression and drug resistance, and reveal that disabling the proteostasis network is a promising strategy to therapeutically target AML.

Antineoplastic Activity of Sodium Caseinate in a Cytarabine-Resistant Mouse Acute Myeloid Leukemia Cell Line.

Acute myeloid leukemia (AML) is a hematological neoplasm of rapid and progressive onset, and is the most common form of leukemia in adults. Chemoresistance to conventional treatments such as cytarabine (Ara-C) and daunorubicin is a main cause of relapse, recurrence, metastasis, and high mortality in AML patients. It is known that sodium caseinate (SC), a salt derived from casein, a milk protein, inhibits growth and induces apoptosis in acute myeloid leukemia cells but not in normal hematopoietic cells. However, it is unknown whether SC retains its antileukemic effect in cytarabine-resistant AML cell lines. To evaluate the antineoplastic effect of SC in cytarabine-resistant leukemia models. The SC inhibits the growth and induces apoptosis in parental WEHI-3 AML cells. Here, we generated two cytarabine-resistant sublines, WEHI-CR25 and WEHI-CR50, which exhibit 6- and 16-fold increased resistance to cytarabine, respectively, compared to the parental WEHI-3 cells. Thus, these sublines mimic a chemoresistant model. We demonstrate that WEHI-CR25 and WEHI-CR50 cells retain sensitivity to SC, similar to parental WEHI-3 cells. This sensitivity results in inhibited cell proliferation, induced apoptosis, and increased expression of ENT1 and dCK, molecules involved in the entry and metabolism of Ara-C, while decreasing MDR1 expression. Additionally, we observed that SC prolonged the survival of WEHI-CR50 tumor-bearing mice, despite their resistance to Ara-C. This is the first evidence that SC, a milk protein, may inhibit proliferation and induce apoptosis in cytarabine-resistant cells.

Methylsulfonylmethane induces caspase-dependent apoptosis in acute myeloid leukemia cell lines.

Acute myeloid leukemia (AML) is a heterogeneous ailment in both biological and clinical concepts. Numerous efforts have been devoted to discover natural compounds for combating cancer, which showed great potential in cancer management. Methylsulfonylmethane (MSM), an organosulfur dietary supplement, is utilized for improving various clinical conditions, particularly osteoarthritis. MSM can exert antitumor activity in a wide range of cancers. The molecular mechanisms of action underlying antileukemic activity of MSM remain unclear. In this regard, we aimed to investigate the anticancer properties of MSM on human AML cell lines (U937 and HL60) with focus on underlying cell death mechanism. Anticancer activity of the MSM was examined employing MTT assay, Annexin V-PE/7AAD staining, caspase3/7 activity test, and real-time qPCR. Both cell lines were treated with different concentrations (50-400 mM) of MSM for 24 h. Pretreatment of the cells with a caspase inhibitor (i.e., Z-VAD-fmk) was performed for the assessment of apoptosis induction. The results of MTT assay revealed that in both cell lines, the MSM markedly reduced cell viability in comparison to the control cells. Additionally, findings of Annexin V-7AAD staining revealed that MSM induced apoptosis and activated caspase 3/7 in both cell lines markedly. Real-time quantitative PCR results also supported the induction of apoptosis in AML cells. MSM altered the expression levels of various apoptotic genes (BAX, BAD, and BIM). Overall, our results indicated that MSM could induce apoptosis in AML cell lines in a dose-dependent manner, which therefore could be utilized as anantileukemic agent.

Genome-wide CRISPR screening identifies critical role of phosphatase and tensin homologous (PTEN) in sensitivity of acute myeloid leukemia to chemotherapy.

Although significant progress has been made in the development of novel targeted drugs for the treatment of acute myeloid leukemia (AML) in recent years, chemotherapy still remains the mainstay of treatment and the overall survival is poor in most patients. Here, we demonstrated the antileukemia activity of a novel small molecular compound NL101, which is formed through the modification on bendamustine with a suberanilohydroxamic acid (SAHA) radical. NL101 suppresses the proliferation of myeloid malignancy cells and primary AML cells. It induces DNA damage and caspase 3-mediated apoptosis. A genome-wide clustered regularly interspaced short palindromic repeats (CRISPR) library screen revealed that phosphatase and tensin homologous (PTEN) gene is critical for the regulation of cell survival upon NL101 treatment. The knockout or inhibition of PTEN significantly reduced NL101-induced apoptosis in AML and myelodysplastic syndrome (MDS) cells, accompanied by the activation of protein kinase B (AKT) signaling pathway. The inhibition of mammalian target of rapamycin (mTOR) by rapamycin enhanced the sensitivity of AML cells to NL101-induced cell death. These findings uncover PTEN protein expression as a major determinant of chemosensitivity to NL101 and provide a novel strategy to treat AML with the combination of NL101 and rapamycin.

Design, synthesis and biological evaluation of novel SIRT3 inhibitors targeting both NAD+ and substrate binding sites for the treatment of acute myeloid leukemia

Acute myeloid leukemia (AML) represents a highly malignant subtype of leukemia with limited therapeutic options. In this study, we propose a novel therapeutic strategy for treating AML by inhibiting SIRT3 to regulate mitochondrial metabolism network involved in energy metabolism and epigenetic modifications essential for AML survival. A series of thieno [3,2-d]pyrimidine-6-carboxamide derivatives were designed and synthesized by structure-based strategy, 17f was documented to be a potent and acceptable selective SIRT3 inhibitor with IC50 value of 0.043 μM and exhibited profound anti-proliferative activity in MOLM13, MV4-11, and HL-60 cells. Through CETSA assay and the degree of deacetylation of intracellular SIRT3 substrates, we confirmed that 17f could effectively bind and inhibit SIRT3 activity in AML cells. Mechanistically, 17f suppressed mitochondrial function, triggered the accumulation of ROS, and significantly inhibited the production of ATP in AML cells. With the breakdown of mitochondrial function, 17f eventually induced apoptosis of AML cells. In addition, 17f also showed excellent anti-AML potential in nude mouse tumor models of HL-60-Luc. Collectively, these results demonstrate that 17f is a potent and acceptable selective SIRT3 inhibitor with promising potential to treat AML.

Discovery of a potent PROTAC degrader for RNA demethylase FTO as antileukemic therapy

The fat mass and obesity-associated protein (FTO) is an RNA demethylase required for catalytic demethylation of N6-methyladenosine (m6A); it is highly expressed and functions as an oncogene in acute myeloid leukemia (AML). Currently, the overarching objective of targeting FTO is to precisely inhibit the catalytic activity. Meanwhile, whether FTO degradation also exerts antileukemic effects remains unknown. Herein, we designed the first FTO-targeting proteolysis targeting chimera (PROTAC) degrader QP73 using our FTO inhibitor Dac85—which potently inhibits FTO demethylation in AML cell lines—as a warhead. Notably, QP73 significantly induced FTO degradation in a time-, dose-, and ubiquitin–proteasome system-dependent manner and had superior antiproliferative activities to the FTO inhibitor Dac85 in various AML cell lines. Moreover, QP73 treatment significantly increased m6A modification on mRNA, promoted myeloid differentiation, and induced apoptosis of AML cells. Quantitative proteomics analysis showed that QP73 induced complete FTO degradation, upregulating RARA and ASB2 abundance and downregulating CEBPA, MYC, PFKP, and LDHB levels in AML cells. Lastly, QP73 exhibited antileukemic activity by increasing m6A modification and decreasing FTO levels in xenograft AML tumors. This proof-of-concept study shows that FTO-targeting PROTAC degraders can regulate the FTO signaling pathway and have potential antileukemia applications.

Lysosomal cation channel TRPML1 suppression sensitizes acute myeloid leukemia cells to chemotherapeutics by inhibiting autophagy.

Despite the implementation of novel therapeutic regimens and extensive research efforts, chemoresistance remains a formidable challenge in the treatment of acute myeloid leukemia (AML). Notably, the involvement of lysosomes in chemoresistance has sparked interest in developing lysosome-targeted therapies to sensitize tumor cells to currently approved chemotherapy or as innovative pharmacological approaches. Moreover, as ion channels on the lysosomal membrane are critical regulators of lysosomal function, they present potential as novel targets for enhancing chemosensitivity. Here, we discovered that the expression of a lysosomal cation channel, namely transient receptor potential mucolipin 1 (TRPML1), was elevated in AML cells. Inhibiting TRPML1 individually does not impact the proliferation and apoptosis of AML cells. Importantly, inhibition of TRPML1 demonstrated the potential to modulate the sensitivity of AML cells to chemotherapeutic agents. Exploration of the underlying mechanisms revealed that suppression of TRPML1 impaired autophagy while concurrently increasing the production of reactive oxygen species (ROS) and ROS-mediated lipid peroxidation (Lipid-ROS) in AML cells. Finally, the knockdown of TRPML1 significantly reduced OCI-AML3 tumor growth following chemotherapy in a mouse model of human leukemia. In summary, targeting TRPML1 represents a promising approach for combination therapy aimed at enhancing chemosensitivity in treating AML.

SFXN3 is a Prognostic Marker and Promotes the Growth of Acute Myeloid Leukemia

Acute myeloid leukemia (AML) is a heterogeneous disease with rapid progression and frequent mutations. Sideroflexin3 (SFXN3) has been shown to be involved in various neurodegenerative diseases. However, the role of SFXN3 in AML remains unclear. The level and prognostic value of SFXN3 were assessed in pan-cancer, especially AML, based on the data obtained from the TCGA database. The effect and mechanism of SFXN3 in AML were measured by fluorescence-activated cell sorting (FACS), qRT-PCR, western blotting in vitro and in vivo. The correlation between SFXN3 and the infiltration of immune cells in AML was assessed via cibersort and ssGSEA analyses. SFXN3 is expressed at higher levels in AML, and high SFXN3 level is associated with decreased overall survival rate (OSR) in AML. Next, knockdown of SFXN3 results in enhanced cell apoptosis and dropped cell proliferation. Then, knockdown of SFXN3 caused a reduction in the expression of CyclinD1 (CCND1) and nuclear factor of kappa light polypeptide gene enhancer in B-cells 1 (NFKB1). Finally, SFXN3 may related to the immunosuppressive state of AML. Increased SFXN3 expression is detected in AML, which indicates a poor prognosis and may link to immunosuppressive state of AML. In addition, SFXN3 can inhibit AML cells apoptosis and promote cell proliferation via enhancing CCND1 and NFKB1 levels.

Pseudolaric Acid B Targets CD147 to Selectively Kill Acute Myeloid Leukemia Cells.

Acute myeloid leukemia (AML) is an aggressive blood cancer. With low survival rates, new drug targets are needed to improve treatment regimens and patient outcomes. Pseudolaric acid B (PAB) is a plant-derived bioactive compound predicted to interact with cluster of differentiation 147 (CD147/BSG). CD147 is a transmembrane glycoprotein overexpressed in various malignancies with suggested roles in regulating cancer cell survival, proliferation, invasion, and apoptosis. However, the detailed function of PAB in AML remains unknown. In this study, AML cell lines and patient-derived cells were used to show that PAB selectively targeted AML (IC50: 1.59 ± 0.47 µM). Moreover, proliferation assays, flow cytometry, and immunoblotting confirmed that PAB targeting of CD147 resulted in AML cell apoptosis. Indeed, the genetic silencing of CD147 significantly suppressed AML cell growth and attenuated PAB activity. Overall, PAB imparts anti-AML activity through transmembrane glycoprotein CD147.

Exploring the mechanism of fraxetin against acute myeloid leukemia through cell experiments and network pharmacology

ObjectivePrevious studies have shown that fraxetin has antitumor activity in a variety of tumors, but its role in acute myeloid leukemia (AML) remains unclear. In this study, we aimed to evaluate the anti-AML effect of fraxetin through cell experiments and network pharmacology analysis.MethodsThe inhibitory and apoptotic effects of fraxetin on AML cells were determined by CCK-8 and flow cytometry experiments. Potential targets of fraxetin and AML-related targets were screened using public databases. PPI network, GO functional enrichment and KEGG pathway enrichment analyses were performed to predict the hub targets and signaling pathways by which fraxetin alleviates AML. Molecular docking was used to determine the fraxetin binding sites on hub targets. Using the GEPIA database, the expression of hub targets was analyzed in relation to the overall survival of AML patients.ResultsCell experiments showed that fraxetin inhibits AML cell proliferation and induces apoptosis. To explore the potential mechanism of fraxetin, 29 shared targets of fraxetin and AML were obtained through screening online public databases. Among them, AKT1, TNF, SRC, etc., are related to AML cell apoptosis. The expression levels of SRC, NOS3, VAV1, LYN, and PTGS1 were associated with the overall survival of AML patients (p value < 0.05). The enrichment analysis results identified the main pathways, namely, focal adhesion and the PI3K-AKT signaling pathway, that affected the proliferation and apoptosis of AML cells. The analysis of hub targets of the PPI network showed that AKT1, TNF, CTNNB1, etc., were hub targets, which were related to the proliferation and apoptosis of AML cells. The results of molecular docking showed that the hub targets had good binding with fraxetin.ConclusionFraxetin may inhibit AML cell proliferation and induce AML cell apoptosis through multiple targets, such as AKT1, SRC, and EGFR, and multiple pathways, such as focal adhesion and the PI3K-AKT signaling pathway.

Marine Cytotoxin Santacruzamate A Derivatives as Potent HDAC1-3 Inhibitors and Their Synergistic Anti-Leukemia Effects with Venetoclax.

Acute myeloid leukemia (AML) is a hematologic malignancy characterized by infiltration of the blood and bone marrow, exhibiting a low remission rate and high recurrence rate. Current research has demonstrated that class I HDAC inhibitors can downregulate anti-apoptotic proteins, leading to apoptosis of AML cells. In the present investigation, we conducted structural modifications of marine cytotoxin Santacruzamate A (SCA), a compound known for its inhibitory activity towards HDACs, resulting in the development of a novel series of potent class I HDACs hydrazide inhibitors. Representative hydrazide-based compound 25c exhibited concentration-dependent induction of apoptosis in AML cells as a single agent. Moreover, 25c exhibited a synergistic anti-AML effect when combined with Venetoclax, a clinical Bcl-2 inhibitor employed in AML therapy. This combination resulted in a more pronounced downregulation of anti-apoptotic proteins Mcl-1 and Bcl-xL, along with a significant upregulation of the pro-apoptotic protein cleaved-caspase3 and the DNA double-strand break biomarker γ-H2AX compared to monotherapy. These results highlighted the potential of 25c as a promising lead compound for AML treatment, particularly when used in combination with Venetoclax.

CSE1L Silencing Enhances Cytarabine-mediated Cytotoxicity in Acute Myeloid Leukemia.

This study aims to investigate the increased toxicity of Cytarabine (Ara-c) by knockdown of chromosome segregation 1-like (CSE1L) in acute myeloid leukemia(AML) cells(Kasumi-1, U937, and THP-1 cells) and to explore its possible mechanisms. Target gene silencing was achieved using the shRNA-mediated lentivirus method. Apoptosis was identified using the Annexin V PE/7-AAD double-staining assay. Cell viability was assessed with the Cell Counting Kit-8 (CCK-8) assay. Protein expression was detected by Western blotting. In vitro, knocking down CSE1L promoted caspase-3 and caspase-9 proteins expression and induced apoptosis in AML cells. Knockdown of CSE1L enhanced AML cells' sensitivity to Ara-c. knockdown of CSE1L reduced the expression levels of p-JKA2 and p-STAT3 proteins, while no significant difference was observed in the expression levels of total JAK2 and STAT3 proteins. Furthermore, JAK2 overexpression reversed the increase in Ara-c toxicity to AML cells caused by CSE1L knockdown. In conclusion, our study reveals that CSE1L is a potential therapeutic target for overcoming Ara-c resistance in AML cells. Thus, we have gained new insights into the oncogenic process of CSE1L in AML cells and raised the prospect of knockdown of CSE1L in AML in combination with cytarabine-targeted therapy.

High STAT4 expression correlates with poor prognosis in acute myeloid leukemia and facilitates disease progression by upregulating VEGFA expression.

The aim of our study is to explore the mechanism of transcription-4 (STAT4) in acute myeloid leukemia (AML). STAT4 level in AML bone marrow samples/cells was analyzed using bioinformatics and quantitative real-time PCR. The correlation between high STAT4 expression and the prognosis of AML patients was analyzed. The viability, apoptosis, and angiogenesis of AML cells were detected. The levels of STAT4, vascular endothelial growth factor A (VEGFA), and apoptosis-related proteins (Bcl-2 and Bax) in transfected AML cells were examined. STAT4 level was upregulated in AML. STAT4 silencing decreased the viability and angiogenesis, yet increased the apoptosis of AML cells, while overexpressed STAT4 did conversely. VEGFA silencing counteracted the impacts of overexpressed STAT4 upon promoting viability and angiogenesis as well as repressing the apoptosis of AML cells. High STAT4 expression was correlated with poor prognosis of AML patients and facilitated disease progression via upregulating VEGFA expression.

UBE2C promotes the proliferation of acute myeloid leukemia cells through PI3K/AKT activation

This study aims to investigate the role and mechanism of tubiquitin-conjugating enzyme E2 C (UBE2C) in acute myeloid leukemia (AML). Initially, UBE2C expression in leukemia was analyzed using the Cancer Genome Atlas database. Further, we silenced UBE2C expression using small-hairpin RNA (sh-RNA). UBE2C expression was detected via the quantitative reverse-transcriptase polymerase chain reaction (qRT-PCR) and Western blot analysis. Apoptotic events and reactive oxygen species (ROS) levels were detected by flow cytometry. A xenograft model of leukemia cells were established, and the protein levels of UBE2C, KI-67, and cleaved-caspase 3 were detected by immunohistochemistry. We reported an overexpression of UBE2C in leukemia patients and cell lines (HL60, THP-1, U937, and KG-1 cells). Moreover, a high expression level of UBE2C was correlated with a dismal prognosis in AML patients. UBE2C knockdown inhibited the viability and promoted apoptosis in AML cells by regulating the phosphatidylinositol-3-kinase (PI3K)/protein kinase B (AKT) signaling pathway. Furthermore, UBE2C knockdown increased cellular Fe2+ and ROS levels, and enhanced erastin-induced ferroptosis in a proteasome-dependent manner. UBE2C knockdown also suppressed the tumor formation of AML cells in the mouse model. In summary, our findings suggest that UBE2C overexpression promotes the proliferation and inhibits ferroptosis in AML cells by activating the PI3K/AKT pathway.

Duocarmycin SA Reduces Proliferation and Increases Apoptosis in Acute Myeloid Leukemia Cells In Vitro.

Acute myeloid leukemia (AML) is a hematological malignancy that is characterized by an expansion of immature myeloid precursors. Despite therapeutic advances, the prognosis of AML patients remains poor and there is a need for the evaluation of promising therapeutic candidates to treat the disease. The objective of this study was to evaluate the efficacy of duocarmycin Stable A (DSA) in AML cells in vitro. We hypothesized that DSA would induce DNA damage in the form of DNA double-strand breaks (DSBs) and exert cytotoxic effects on AML cells within the picomolar range. Human AML cell lines Molm-14 and HL-60 were used to perform 3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide (MTT), DNA DSBs, cell cycle, 5-ethynyl-2-deoxyuridine (EdU), colony formation unit (CFU), Annexin V, RNA sequencing and other assays described in this study. Our results showed that DSA induced DNA DSBs, induced cell cycle arrest at the G2M phase, reduced proliferation and increased apoptosis in AML cells. Additionally, RNA sequencing results showed that DSA regulates genes that are associated with cellular processes such as DNA repair, G2M checkpoint and apoptosis. These results suggest that DSA is efficacious in AML cells and is therefore a promising potential therapeutic candidate that can be further evaluated for the treatment of AML.

Targeting Metabolic Dependencies Fueling the TCA Cycle to Circumvent Therapy Resistance in Acute Myeloid Leukemia.

Acute myeloid leukemia (AML) is one of the most prevalent blood cancers, characterized by a dismal survival rate. This poor outcome is largely attributed to AML cells that persist despite treatment and eventually result in relapse. Relapse-initiating cells exhibit diverse resistance mechanisms, encompassing genetic factors and, more recently discovered, nongenetic factors such as metabolic adaptations. Leukemic stem cells (LSC) rely on mitochondrial metabolism for their survival, whereas hematopoietic stem cells primarily depend on glycolysis. Furthermore, following treatments such as cytarabine, a standard in AML treatment for over four decades, drug-persisting leukemic cells exhibit an enhanced reliance on mitochondrial metabolism. In this issue of Cancer Research, two studies investigated dependencies of AML cells on two respiratory substrates, α-ketoglutarate and lactate-derived pyruvate, that support mitochondrial oxidative phosphorylation (OXPHOS) following treatment with the imipridone ONC-213 and the BET inhibitor INCB054329, respectively. Targeting lactate utilization by interfering with monocarboxylate transporter 1 (MCT1 or SLC16A1) or lactate dehydrogenase effectively sensitized cells to BET inhibition in vitro and in vivo. In addition, ONC-213 affected αKGDH, a pivotal NADH-producing enzyme of the TCA cycle, to induce a mitochondrial stress response through ATF4 activation that diminished the expression of the antiapoptotic protein MCL1, consequently promoting apoptosis of AML cells. In summary, targeting these mitochondrial dependencies might be a promising strategy to kill therapy-naïve and treatment-resistant OXPHOS-reliant LSCs and to delay or prevent relapse. See related articles by Monteith et al., p. 1101 and Su et al., p. 1084.