An Overview of Targeted Therapies in Acute Myeloid Leukemia

Caspase 3-specific cleavage of ubiquitin-specific peptidase 48 enhances drug-induced apoptosis in AML

Dysfunction or dysregulation of deubiquitination is closely related to the initiation and development of multiple cancers. Targeted regulation of deubiquitination has been recognized as an important strategy in tumor therapy. However, the mechanism by which drugs regulate deubiquitinase is not clear. Here, we identified ubiquitin-specific peptidase 48 (USP48), a member of the ubiquitin-specific protease family highly expressed in various tumors, as a specific substrate for the activated caspase-3. During drug induced apoptosis of AML cells, activated caspase-3 cleaves USP48 through recognizing the conservative motif DEQD located at 611-614 sites of human USP48. Subsequent analysis showed that the cleavage USP48 N-terminal fragment which contains catalytic active domain is easily degraded by ubiquitination. Meanwhile knockdown experiment showed that inhibiting the expression of USP48 could also promotes apoptosis and enhance the efficacy of chemotherapy drugs. Altogether, these results suggest that targeting USP48 may represent a novel therapeutic strategy in AML.

Safety, tolerability, and pharmacokinetics of ASP1235 in relapsed or refractory acute myeloid leukemia: A phase 1 study

Acute myeloid leukemia (AML) is an aggressive hematologic malignancy. Although new agents including targeted therapies for relapsed or refractory (R/R) AML have been introduced, poor outcomes remain, requiring the need for novel approaches. One novel approach is the use of antibody-drug conjugates (ADCs). We conducted an early phase clinical trial with ASP1235, an ADC targeting FMS-like tyrosine kinase 3. In total, 43 patients with R/R AML were treated with ASP1235. The most common adverse events (AEs) included elevated liver transaminase levels, ocular toxicity, and muscular weakness. Ocular treatment-emergent AEs (TEAEs) were observed in 53 % of patients; most were mild or moderate in severity. The most common ocular TEAEs were blurred vision, dry eye, keratitis, photophobia, and reduced visual acuity. Serious (grade ≥3) ocular TEAEs occurred in 16.3 % of patients, with only 1 patient experiencing grade 4 keratitis. Six patients achieved composite complete remission (complete remission [CR] + CR with incomplete hematologic recovery + CR with incomplete platelet recovery), 2 of whom proceeded to hematopoietic cell transplantation with long-term leukemia-free survival. This trial was registered at www.clinicaltrials.gov as #NCT02864290.

Development and comparison of single FLT3-inhibitors to dual FLT3/TAF1-inhibitors as an anti-leukemic approach

Acute myeloid leukemia (AML) is characterized by several recurrent mutations that affect disease biology and phenotype, response to therapy and risk of subsequent relapse. Though tyrosine kinase inhibitors have gained regulatory approval for the treatment of AML, it is unclear whether single drugs targeting a specific genomic alteration will be sufficient to eradicate disease. Fortuitously, kinase/bromodomain inhibitors allow targeting of downstream transcriptional effectors of oncogenic pathways, allowing impediment of drug resistance at the transcriptional level. Successful development of combinatorial therapeutic strategies to inhibit both upstream oncogenic pathways and their downstream effectors could thus impede the onset of resistant disease. By using a combination of high-throughput cell-based screening assays and structure-based design, we have developed a novel anti-proliferative 3i-compound scaffold with a diverse range of single and dual FLT3/TAF1(2) activity against AML. Our novel approach to target both FLT3 kinase and TAF1(2) bromodomain efficiently maintained potency against haematological cancers. However, reference compounds and in vitro cell viability and cytotoxicity assays in cancer cell lines demonstrated superior effects of high affinity tyrosine kinase inhibition compared to inhibition of the TAF1 bromodomain. Our results highlight the feasibility of dual tyrosine kinase-bromodomain targeting to overcome disease mechanisms while also revealing the increased efficacy of FLT3-targeted compounds in AML.

The evolving role of B cells in malignancies

B cells play diverse roles in different pathological circumstances, such as neoplastic diseases, autoimmune disorders, and neurological maladies. B cells, which are essential elements of the adaptive immune system, demonstrate exceptional functional variety, including the generation of antibodies, the presentation of antigens, and the secretion of cytokines. Within the field of oncology, B cells display a multifaceted nature in the tumor microenvironment, simultaneously manifesting both tumor-promoting and tumor-suppressing characteristics. Studies have found that the existence of tertiary lymphoid structures, which consist of B cells, is linked to better survival rates in different types of cancers. This article examines the involvement of B cells in different types of malignancies, emphasizing their importance in the development of the diseases and their potential as biomarkers. Additionally, the review also examines the crucial role of B cells in autoimmune illnesses and their potential as targets for therapy. The article also analyses the role of B cells in immunization and exploring their potential uses in cancer immunotherapy. This analysis highlights the intricate and occasionally contradictory roles of B cells, underlining the necessity for additional research to clarify their varied actions in various illness scenarios.

Molecular principles underlying aggressive cancers

Aggressive tumors pose ultra-challenges to drug resistance. Anti-cancer treatments are often unsuccessful, and single-cell technologies to rein drug resistance mechanisms are still fruitless. The National Cancer Institute defines aggressive cancers at the tissue level, describing them as those that spread rapidly, despite severe treatment. At the molecular, foundational level, the quantitative biophysics discipline defines aggressive cancers as harboring a large number of (overexpressed, or mutated) crucial signaling proteins in major proliferation pathways populating their active conformations, primed for their signal transduction roles. This comprehensive review explores highly aggressive cancers on the foundational and cell signaling levels, focusing on the differences between highly aggressive cancers and the more treatable ones. It showcases aggressive tumors as harboring massive, cancer-promoting, catalysis-primed oncogenic proteins, especially through certain overexpression scenarios, as predisposed aggressive tumor candidates. Our examples narrate strong activation of ERK1/2, and other oncogenic proteins, through malfunctioning chromatin and crosslinked signaling, and how they activate multiple proliferation pathways. They show the increased cancer heterogeneity, plasticity, and drug resistance. Our review formulates the principles underlying cancer aggressiveness on the molecular level, discusses scenarios, and describes drug regimen (single drugs and drug combinations) for PDAC, NSCLC, CRC, HCC, breast and prostate cancers, glioblastoma, neuroblastoma, and leukemia as examples. All show overexpression scenarios of master transcription factors, transcription factors with gene fusions, copy number alterations, dysregulation of the epigenetic codes and epithelial-to-mesenchymal transitions in aggressive tumors, as well as high mutation loads of vital upstream signaling regulators, such as EGFR, c-MET, and K-Ras, befitting these principles.

Flow cytometry in acute myeloid leukemia and detection of minimal residual disease

Acute myeloid leukemia (AML) is a common type of acute leukemia (AL), belonging to malignant tumors of the hematopoietic system with the characteristics of rapid disease development, control with extreme difficulties, easy recurrence, poor prognosis, and incidence rate increasing with age. The traditionally diagnostic standard of French American British (FAB), being based on the morphological examination with high human subjectivity, can no longer meet the demand of clinical diagnosis and treatment of AML. Requirements of objective accuracy and low-dose sample, have become the indispensable method for AML diagnosis and monitoring prognosis. Flow cytometry is a modern technology that can quickly and accurately detect the series, antigen distribution, differentiation stage of AML cells, minimal residual lesions after AML therapy, so as to provide the great significance in guiding clinical diagnosis, hierarchical treatment, and prognosis judgement. This article will systematically elaborate on the application of flow cytometry in the diagnosis and classification of AML, and the detection of minimal residual lesions, thereby providing reference significance for dynamic monitoring and prognostic observation of AML with different immune subtypes of FAB.

M1 macrophage-derived exosomes alleviate leukemia by causing mitochondrial dysfunction

Acute myeloid leukemia (AML) is one type of blood cancer that initially has a high cure rate but frequently relapses and leading to death. Therefore, there is an urgent need for innovative AML treatments. The leukemia C1498 cells were co-cultured with M1 macrophage-derived exosomes (M1-exo), and the proliferation and apoptosis of C1498 cells were investigated using CCK-8 and flow cytometry, respectively. qPCR and Western blot were applied to determine the PGAM5 expression in M1-exo treated C1498 cells. The role of M1-exo-derived PGAM5 in mitochondria was examined via fluorescence staining. The anti-inflammatory effects of M1-exo-derived PGAM5 and M1-exo were evaluated by flow cytometry, HE staining, and immunohistochemistry in xenograft and nude mouse tumorigenic models. M1-exo exhibited a potent capability to attenuate C1498 cell proliferation, and induce cell apoptosis. In vivo experimentation demonstrated that administration of M1-exo led to a reduction in leukocyte count, alleviated inflammatory infiltration, decreased liver and spleen weights, and significantly diminished tumor size. PGAM5 was elevated in M1-exo, and knockdown of PGAM5 in C1498 cells and M1-exo enhanced proliferation and reduced apoptosis in C1498 cells. Concurrently, M1-exo-derived PGAM5 decreased mitochondrial membrane potential and increased calcium influx in vitro. In vivo, studies showed that knockdown of PGAM5 in M1-exo elevated liver and spleen weights, augmented tumor size, and intensified hepatic inflammatory infiltration. Our study reveals that M1-exo induces mitochondrial dysfunction against leukemia through PGAM5.

Acute myeloid leukemia (AML) with chromosome 3 inversion: biology, management, and clinical outcome

Acute myeloid leukemia (AML) is a complex hematological malignancy characterized by diverse genetic alterations, each with distinct clinical implications. Chromosome 3 inversion (inv(3)) is a rare genetic anomaly found in approximately 1.4-1.6% of AML cases, which profoundly affects prognosis. This review explores the pathophysiology of inv(3) AML, focusing on fusion genes like GATA2::EVI1 or GATA2::MECOM. These genetic rearrangements disrupt critical cellular processes and lead to leukemia development. Current treatment modalities, including intensive chemotherapy (IC), hypomethylating agents (HMAs) combined with venetoclax, and allogeneic stem cell transplantation are discussed, highlighting outcomes achieved and their limitations. The review also addresses subgroups of inv(3) AML, describing additional mutations and their impact on treatment response. The poor prognosis associated with inv(3) AML underscores the urgent need to develop more potent therapies for this AML subtype. This comprehensive overview aims to contribute to a deeper understanding of inv(3) AML and guide future research and treatment strategies.

Acute Myeloid Leukemia in Older Patients: From New Biological Insights to Targeted Therapies

Acute myeloid leukemia (AML) is a heterogeneous blood-related neoplasm that predominantly afflicts older adults with a poor prognosis due to their physical condition and the presence of medical accompanying comorbidities, adverse biological disease features, and suitability for induction intensive chemotherapy and allogenic stem cells transplantation. Recent research into the molecular and biological factors contributing to disease development and progression has led to significant advancements in treatment approaches for older patients with AML. This review article discusses the latest biological and therapeutic developments that are transforming the management of AML in older adults.

Finding potential targets in cell-based immunotherapy for handling the challenges of acute myeloid leukemia

Acute myeloid leukemia (AML) is a hostile hematological malignancy under great danger of relapse and poor long-term survival rates, despite recent therapeutic advancements. To deal with this unfulfilled clinical necessity, innovative cell-based immunotherapies have surfaced as promising approaches to improve anti-tumor immunity and enhance patient outcomes. In this comprehensive review, we provide a detailed examination of the latest developments in cell-based immunotherapies for AML, including chimeric antigen receptor (CAR) T-cell therapy, T-cell receptor (TCR)-engineered T-cell therapy, and natural killer (NK) cell-based therapies. We critically evaluate the unique mechanisms of action, current challenges, and evolving strategies to improve the efficacy and safety of these modalities. The review emphasizes how promising these cutting-edge immune-based strategies are in overcoming the inherent complexities and heterogeneity of AML. We discuss the identification of optimal target antigens, the importance of mitigating on-target/off-tumor toxicity, and the need to enhance the persistence and functionality of engineered immune effector cells. All things considered, this review offers a thorough overview of the rapidly evolving field of cell-based immunotherapy for AML, underscoring the significant progress made and the ongoing efforts to translate these innovative approaches into more effective and durable treatments for this devastating disease.

Case report: Successful combination of CLL1 CAR-T therapy and hematopoietic stem cell transplantation in a 73-year-old patient diagnosed with refractory acute myeloid leukemia

The incidence of Acute myeloid leukemia (AML) increases with advancing age, and the prognosis for elderly patients is significantly poorer compared to younger patients. Although the combination therapy of venetoclax and hypomethylating agents has demonstrated improved prognosis in patients unable to tolerate intensive chemotherapy, there remains a therapeutic blank for those who fail to achieve remission with current treatment regimens. Here, we report the successful clinical utilization of autogenous CLL1 CAR-T therapy combined with hematopoietic stem cell transplantation in a 73-year-old patient diagnosed with refractory AML. The patient achieved morphological complete remission (CR) with incomplete marrow recovery and a slight presence of minimal residual disease (MRD) after receiving CLL1 CAR-T therapy. To further enhance the treatment and promote the recovery of hemopoiesis, we performed bridged allogenic hematopoietic stem cell transplantation (allo-HSCT) 20 days after the infusion of CLL1 CAR-T cells. The patient achieved MRD-negative CR following HSCT treatment. His primary disease maintained a complete remission status during the 11-month follow-up period. The patient encountered grade 2 cytokine release syndrome and grade 4 granulocytopenia subsequent to the infusion of CAR-T cells, while several rounds of infection and graft-versus-host disease were observed following allo-HSCT. Nevertheless, all these concerns were successfully addressed through comprehensive provision of supportive treatments. We have successfully demonstrated a highly effective and safe combination strategy involving CLL1 CAR-T therapy and allo-HSCT, which has exhibited remarkable tolerability and holds great promise even for elderly patients with AML.

Enhancing Therapeutic Efficacy of FLT3 Inhibitors with Combination Therapy for Treatment of Acute Myeloid Leukemia

FMS-like tyrosine kinase 3 (FLT3) mutations are genetic changes found in approximately thirty percent of patients with acute myeloid leukemia (AML). FLT3 mutations in AML represent a challenging clinical scenario characterized by a high rate of relapse, even after allogeneic hematopoietic stem cell transplantation (allo-HSCT). The advent of FLT3 tyrosine kinase inhibitors (TKIs), such as midostaurin and gilteritinib, has shown promise in achieving complete remission. However, a substantial proportion of patients still experience relapse following TKI treatment, necessitating innovative therapeutic strategies. This review critically addresses the current landscape of TKI treatments for FLT3+ AML, with a particular focus on gilteritinib. Gilteritinib, a highly selective FLT3 inhibitor, has demonstrated efficacy in targeting the mutant FLT3 receptor, thereby inhibiting aberrant signaling pathways that drive leukemic proliferation. However, monotherapy with TKIs may not be sufficient to eradicate AML blasts. Specifically, we provide evidence for integrating gilteritinib with mammalian targets of rapamycin (mTOR) inhibitors and interleukin-15 (IL-15) complexes. The combination of gilteritinib, mTOR inhibitors, and IL-15 complexes presents a compelling strategy to enhance the eradication of AML blasts and enhance NK cell killing, offering a potential for improved patient outcomes.

Acute Myelomonoblastic Leukemia (My1/De): A Preclinical Rat Model

BACKGROUND/AIM

Since acute myeloid leukemias still represent the most aggressive type of adult acute leukemias, the profound understanding of disease pathology is of paramount importance for diagnostic and therapeutic purposes. Hence, this study aimed to explore the real-time disease fate with the establishment of an experimental myelomonoblastic leukemia (My1/De) rat model using preclinical positron emission tomography (PET) and whole-body autoradiography.

MATERIALS AND METHODS

In vitro [18F]F-FDG uptake studies were performed to compare the tracer accumulation in the newly cultured My1/De tumor cell line (blasts) with that in healthy control and My1/De bone marrow suspensions. Post transplantation of My1/De cells under the left renal capsule of Long-Evans rats, primary My1/De tumorigenesis, and metastatic propagation were investigated using [18F]F-FDG PET imaging, whole-body autoradiography and phosphorimage analyses. To assess the organ uptake profile of the tumor-carrying animals we accomplished ex vivo biodistribution studies.

RESULTS

The tracer accumulation in the My1/De culture cells exceeded that of both the tumorous and the healthy bone marrow suspensions (p<0.01). Based on in vivo imaging, the subrenally transplanted My1/De cells resulted in the development of leukemia in the abdominal organs, and metastasized to the mesenterial and thoracic parathymic lymph nodes (PTLNs). The lymphatic spread of metastasis was further confirmed by the significantly higher %ID/g values of the metastatic PTLNs (4.25±0.28) compared to the control (0.94±0.34). Cytochemical staining of the peripheral blood, autopsy findings, and wright-Giemsa-stained post-mortem histological sections proved the leukemic involvement of the assessed tissues/organs.

CONCLUSION

The currently established My1/De model appears to be well-suited for further leukemia-related therapeutic and diagnostic investigations.

Induction of AML cell differentiation using HOXA9/DNA binding inhibitors as a potential therapeutic option for HOXA9-dependent AML

The mainstay of acute myeloid leukemia (AML) treatment still relies on traditional chemotherapy, with a survival rate of approximately 30% for patients under 65 years of age and as low as 5% for those beyond. This unfavorable prognosis primarily stems from frequent relapses, resistance to chemotherapy, and limited approved targeted therapies for specific AML subtypes. Around 70% of all AML cases show overexpression of the transcription factor HOXA9, which is associated with a poor prognosis, increased chemoresistance, and higher relapse rates. However, direct targeting of HOXA9 in a clinical setting has not been achieved yet. The dysregulation caused by the leukemic HOXA9 transcription factor primarily results from its binding activity to DNA, leading to differentiation blockade. Our previous investigations have identified two HOXA9/DNA binding competitors, namely DB1055 and DB818. We assessed their antileukemic effects in comparison to HOXA9 knockdown or cytarabine treatment. Using human AML cell models, DB1055 and DB818 induced in vitro cell growth reduction, death, differentiation, and common transcriptomic deregulation but did not impact human CD34+ bone marrow cells. Furthermore, DB1055 and DB818 exhibited potent antileukemic activities in a human THP-1 AML in vivo model, leading to the differentiation of monocytes into macrophages. In vitro assays also demonstrated the efficacy of DB1055 and DB818 against AML blasts from patients, with DB1055 successfully reducing leukemia burden in patient-derived xenografts in NSG immunodeficient mice. Our findings indicate that inhibiting HOXA9/DNA interaction using DNA ligands may offer a novel differentiation therapy for the future treatment of AML patients dependent on HOXA9.

Formononetin and Dihydroartemisinin Act Synergistically to Induce Apoptosis in Human Acute Myeloid Leukemia Cell Lines

OBJECTIVE

Enhanced cell survival and drug resistance in tumor cells have been linked to the overexpression of antiapoptotic members of the Bcl-2 family proteins, including Bcl-2 and Mcl-1. The aim of this study was to explore the impact of formononetin and dihydroartemisinin combination on the growth and apoptosis of acute myeloid leukemia (AML) cells.

MATERIALS AND METHODS

In this experimental study, the cell survival and cell proliferation were tested by MTT assay and trypan blue staining. The evaluation of cell apoptosis was conducted using Hoechst 33342 staining and a colorimetric assay to measure caspase-3 activity. To determine the mRNA levels of Mcl-1, Bcl-2, Bax, and Cyclin D1, a quantitative real-time polymerase chain reaction (qRT-PCR) was performed.

RESULTS

We showed that treatment with either formononetin or dihydroartemisinin alone, led to significant decrease in the cell survival and growth, and triggered apoptosis in U937 and KG-1 AML cell lines. Moreover, treatment with each of the compounds alone significantly decreased the mRNA levels of Mcl-1, Bcl-2 and Cyclin D1 mRNA, while, the expression level of Bax mRNA was enhanced. Combination of two compounds showed a synergistic anti-cancer effect.

CONCLUSION

The anti-leukemic potential of formononetin and dihydroartemisinin is exerted through the effect on cell cycle progression and intrinsic pathway of apoptosis. Therefore, they can be considered as a potential anti-leukemic agent alone or along with existing chemotherapeutic drugs.

The Effects of ABT-199 and Dihydroartemisinin Combination on Cell Growth and Apoptosis in Human U937 and KG-1 Cancer Cells

INTRODUCTION

Change in the balance of Bcl-2 family proteins is one of the main reasons for resistance of tumor cells to ABT-199. In this study, the effect of dihydroartemisinin on cell growth, apoptosis and sensitivity of the AML cells to ABT-199 was investigated.

METHODS

Cell proliferation and survival were assessed by trypan blue staining and MTT assay, respectively. Cell apoptosis was measured by Hoechst 33342 staining and caspase-3 activity assay. The expression levels of Bcl-2, Mcl-1 and Bax mRNA were tested by qRT-PCR.

RESULTS

Our data showed that combination therapy significantly reduced the IC50 value and synergistically decreased the AML cell survival and growth compared with dihydroartemisinin or ABT-199 alone. Treatment with each of ABT-199 or dihydroartemisinin alone clearly enhanced the Bax mRNA expression and inhibited the expression of Mcl-1 and Bcl-2 mRNA. Inhibition of Mcl-1 mRNA by dihydroartemisinin was associated with enhancement of apoptosis induced by ABT-199 in AML cells.

CONCLUSION

In conclusion, dihydroartemisinin not only triggers the intrinsic pathway of apoptosis, but also can increase the sensitivity of the AML cells to ABT-199 via suppression of Mcl-1 expression.

Machine Learning Predicts 30-Day Outcome among Acute Myeloid Leukemia Patients: A Single-Center, Retrospective, Cohort Study

Acute myeloid leukemia (AML) is a clinical emergency requiring treatment and results in high 30-day (D30) mortality. In this study, the prediction of D30 survival was studied using a machine learning (ML) method. The total cohort consisted of 1700 survivors and 130 non-survivors at D30. Eight clinical and 42 laboratory variables were collected at the time of diagnosis by pathology. Among them, six variables were selected by a feature selection method: induction chemotherapy (CTx), hemorrhage, infection, C-reactive protein, blood urea nitrogen, and lactate dehydrogenase. Clinical and laboratory data were entered into the training model for D30 survival prediction, followed by testing. Among the tested ML algorithms, the decision tree (DT) algorithm showed higher accuracy, the highest sensitivity, and specificity values (95% CI) of 90.6% (0.918-0.951), 70.4% (0.885-0.924), and 92.1% (0.885-0.924), respectively. DT classified patients into eight specific groups with distinct features. Group 1 with CTx showed a favorable outcome with a survival rate of 97.8% (1469/1502). Group 6, with hemorrhage and the lowest fibrinogen level at diagnosis, showed the worst survival rate of 45.5% (25/55) and 20.5 days. Prediction of D30 survival among AML patients by classification of patients with DT showed distinct features that might support clinical decision-making.