From Bench to Bedside and Beyond: Therapeutic Scenario in Acute Myeloid Leukemia

A novel bispecific T-cell engager using the ligand-target csGRP78 against acute myeloid leukemia

Current medical therapies for treating acute myeloid leukemia (AML) remain unmet, and AML patients may benefit from targeted immunotherapy approaches that focus on specific tumor antigens. GRP78, which is upregulated in various malignant tumors such as AML, is partially expressed as cell surface GRP78 (csGRP78) on the cell membrane, making it an ideal target for redirecting T cells, including T-cell engagers. However, considering the conventional approach of using two scFv segments to construct a bispecific T-cell engager (BiTE), we have undertaken the development of a novel BiTE that utilizes a cyclic peptide ligand to specifically target csGRP78, which we refer to as GRP78-CD3/BiTE. We studied the effects of GRP78-CD3/BiTE on treatments for AML in vitro and in vivo and assessed the pharmacokinetics of this engager. Our findings demonstrated that GRP78-CD3/BiTE could not only effectively mediate the cytotoxicity of T cells against csGRP78-expressing AML cells but also specifically eliminate primary AML tumor cells in vitro. Furthermore, GRP78-CD3/BiTE exhibited a longer half-life despite having a lower molecular weight than CD19-CD3/BiTE. In a xenograft mouse model of AML, treatment with GRP78-CD3/BiTE prolonged the survival time of the mice. Our findings demonstrate that GRP78-CD3/BiTE is effective and selective for eliminating csGRP78-expressing AML cells and suggest that this approach to targeted immunotherapy could lead to effective new treatments for AML.

Advances in the pathogenesis of FLT3-mutated acute myeloid leukemia and targeted treatments

PURPOSE OF REVIEW

FLT3 mutations are among the most common myeloid drivers identified in adult acute myeloid leukemia (AML). Their identification is crucial for the precise risk assessment because of the strong prognostic significance of the most recurrent type of FLT3 alterations, namely internal tandem duplications (ITDs). Recent advances in the pathogenesis and biology of FLT3-mutated AML have opened an opportunity for development and application of selective inhibition of FLT3 pathway.

RECENT FINDINGS

In the last decade, at least three targeted treatments have been approved by regulatory agencies and several others are currently under investigations. Here, we review the latest advance in the role of FLT3 mutations in AML, providing an outline of the available therapeutic strategies, their mechanisms of actions and of resistance, as well as routes for potential improvement.

SUMMARY

The availability of FLT3 inhibitors has improved outcomes in AML harboring such mutations, currently also reflected in disease stratification and recommendations. Newer inhibitors are under investigations, and combinations with chemotherapy or other targeted treatments are being explored to further improve disease outcomes.

Molecular mechanisms of ferroptosis and its roles in leukemia

Cell death is a complex process required to maintain homeostasis and occurs when cells are damage or reach end of life. As research progresses, it is apparent that necrosis and apoptosis do not fully explain the whole phenomenon of cell death. Therefore, new death modalities such as autophagic cell death, and ferroptosis have been proposed. In recent years, ferroptosis, a new type of non-apoptotic cell death characterized by iron-dependent lipid peroxidation and reactive oxygen species (ROS) accumulation, has been receiving increasing attention. Ferroptosis can be involved in the pathological processes of many disorders, such as ischemia-reperfusion injury, nervous system diseases, and blood diseases. However, the specific mechanisms by which ferroptosis participates in the occurrence and development of leukemia still need to be more fully and deeply studied. In this review, we present the research progress on the mechanism of ferroptosis and its role in leukemia, to provide new theoretical basis and strategies for the diagnosis and treatment of clinical hematological diseases.

LncRNA MAFG-AS1-induced acute myeloid leukemia development via modulating miR-147b/HOXA9

Recent references discovered that lncRNAs acted roles in malignant cancer development. However, the role of MAFG-AS1 in acute myeloid leukemia (AML) development remains unknown. MAFG-AS1 and miR-147b were determined in AML cells and specimens using qRT-PCR assay. Cell proliferation was detected by CCK-8 analysis and flow cytometry was carried out to measure cell cycle. Luciferase reporter analysis was done to determine the mechanism of MAFG-AS1 and miR-147b. We noted that MAFG-AS1 was overexpressed in AML cells and in serum and bone narrow from AML compared with normal controls specimen. Elevated expression of MAFG-AS1 increased cell growth, cycle and EMT in AML cell HL-60 cell. MAFG-AS1 sponged miR-147b expression in HL-60 cell. Moreover, miR-147b was downregulated in AML cells and in serum and bone narrow from AML compared with normal control specimen. miR-147b was negatively correlated with MAFG-AS1 in the serum and bone narrow of AML cases. We illustrated that HOXA9 was one target of miR-147b and ectopic expression of MAFG-AS1 enhanced HOXA9 expression HL-60 cell. Forced expression of MAFG-AS1 induced cell growth, cycle, and EMT via promoting HOXA9. These data illustrated that MAFG-AS1 acted as one oncogenic gene and accelerated AML progression via modulating miR-147b/HOXA9 axis.

A Focus on Intermediate-Risk Acute Myeloid Leukemia: Sub-Classification Updates and Therapeutic Challenges

Acute myeloid leukemia (AML) represents a heterogeneous group of hematopoietic neoplasms deriving from the abnormal proliferation of myeloid progenitors in the bone marrow. Patients with AML may have highly variable outcomes, which are generally dictated by individual clinical and genomic characteristics. As such, the European LeukemiaNet 2017 and 2022 guidelines categorize newly diagnosed AML into favorable-, intermediate-, and adverse-risk groups, based on their molecular and cytogenetic profiles. Nevertheless, the intermediate-risk category remains poorly defined, as many patients fall into this group as a result of their exclusion from the other two. Moreover, further genomic data with potential prognostic and therapeutic influences continue to emerge, though they are yet to be integrated into the diagnostic and prognostic models of AML. This review highlights the latest therapeutic advances and challenges that warrant refining the prognostic classification of intermediate-risk AML.

Molecular Mechanisms of Ferroptosis and Its Roles in Hematologic Malignancies

Cell death is essential for the normal metabolism of human organisms. Ferroptosis is a unique regulated cell death (RCD) mode characterized by excess accumulation of iron-dependent lipid peroxide and reactive oxygen species (ROS) compared with other well-known programmed cell death modes. It has been currently recognized that ferroptosis plays a rather important role in the occurrence, development, and treatment of traumatic brain injury, stroke, acute kidney injury, liver damage, ischemia–reperfusion injury, tumor, etc. Of note, ferroptosis may be explained by the expression of various molecules and signaling components, among which iron, lipid, and amino acid metabolism are the key regulatory mechanisms of ferroptosis. Meanwhile, tumor cells of hematological malignancies, such as leukemia, lymphoma, and multiple myeloma (MM), are identified to be sensitive to ferroptosis. Targeting potential regulatory factors in the ferroptosis pathway may promote or inhibit the disease progression of these malignancies. In this review, a systematic summary was conducted on the key molecular mechanisms of ferroptosis and the current potential relationships of ferroptosis with leukemia, lymphoma, and MM. It is expected to provide novel potential therapeutic approaches and targets for hematological malignancies.

Non-Ablative Chemotherapy Followed by HLA-Mismatched Allogeneic CD3+ T-Cells Infusion Causes An Augment of T-Cells With Mild CRS: A Multi-Centers Single-Arm Prospective Study on Elderly Acute Myeloid Leukemia and int-2/High Risk Myelodysplastic Syndrome Patients

Objective

To evaluate the efficacy and safety of standard or low-dose chemotherapy followed by HLA-mismatched allogeneic T-cell infusion (allo-TLI) for the treatment of elderly patients with acute myeloid leukemia (AML) and patients with intermediate-2 to high-risk myelodysplastic syndrome (MDS).

Methods

We carried out a prospective, multicenter, single-arm clinical trial. Totally of 25 patients were enrolled, including 17 AML patients and 8 MDS patients. Each patient received four courses of non-ablative chemotherapy, with HLA-mismatched donor CD3⁺ allo-TLI 24 h after each course. AML patients received chemotherapy with decitabine, idarubicin, and cytarabine, and MDS patients received decitabine, cytarabine, aclarubicin, and granulocyte colony-stimulating factor.

Results

A total of 79 procedures were performed. The overall response rates of the AML and MDS patients were 94% and 75% and the 1-year overall survival rates were 88% (61-97%) and 60% (13-88%), respectively. The overall 60-day treatment-related mortality was 8%. Compared with a historical control cohort that received idarubicin plus cytarabine (3 + 7), the study group showed significantly better overall response (94% vs. 50%, P=0.002) and overall survival rates (the 1-year OS rate was 88% vs. 27%, P=0.014). Post-TLI cytokine-release syndrome (CRS) occurred after 79% of allo-TLI operations, and 96% of CRS reactions were grade 1.

Conclusion

Elderly AML patients and intermediate-2 to high-risk MDS patients are usually insensitive to or cannot tolerate regular chemotherapies, and may not have the opportunity to undergo allogeneic stem cell transplantation. Our study showed that non-ablative chemotherapy followed by HLA-mismatched allo-TLI is safe and effective, and may thus be used as a first-line treatment for these patients.

Clinical Trial Registration

https://www.chictr.org.cn/showproj.aspx?proj=20112.

The Interactome between Metabolism and Gene Mutations in Myeloid Malignancies

The study of metabolic deregulation in myeloid malignancies has led to the investigation of metabolic-targeted therapies considering that cells undergoing leukemic transformation have excessive energy demands for growth and proliferation. However, the most difficult challenge in agents targeting metabolism is to determine a window of therapeutic opportunities between normal and neoplastic cells, considering that all or most of the metabolic pathways important for cancer ontogeny may also regulate physiological cell functions. Targeted therapies have used the properties of leukemic cells to produce altered metabolic products when mutated. This is the case of IDH1/2 mutations generating the abnormal conversion of α-ketoglutarate (KG) to 2-hydroxyglutarate, an oncometabolite inhibiting KG-dependent enzymes, such as the TET family of genes (pivotal in characterizing leukemia cells either by mutations, e.g., TET2, or by altered expression, e.g., TET1/2/3). Additional observations derive from the high sensitivity of leukemic cells to oxidative phosphorylation and its amelioration using BCL-2 inhibitors (Venetoclax) or by disrupting the mitochondrial respiration. More recently, nicotinamide metabolism has been described to mediate resistance to Venetoclax in patients with acute myeloid leukemia. Herein, we will provide an overview of the latest research on the link between metabolic pathways interactome and leukemogenesis with a comprehensive analysis of the metabolic consequences of driver genetic lesions and exemplificative druggable pathways.

Digital Polymerase Chain Reaction Paired with High-Speed Atomic Force Microscopy for Quantitation and Length Analysis of DNA Length Polymorphisms

DNA length polymorphisms are found in many serious diseases, and assessment of their length and abundance is often critical for accurate diagnosis. However, measuring their length and frequency in a mostly wild-type background, as occurs in many situations, remains challenging due to their variable and repetitive nature. To overcome these hurdles, we combined two powerful techniques, digital polymerase chain reaction (dPCR) and high-speed atomic force microscopy (HSAFM), to create a simple, rapid, and flexible method for quantifying both the size and proportion of DNA length polymorphisms. In our approach, individual amplicons from each dPCR partition are imaged and sized directly. We focused on internal tandem duplications (ITDs) located within the FLT3 gene, which are associated with acute myeloid leukemia and often indicative of a poor prognosis. In an analysis of over 1.5 million HSAFM-imaged amplicons from cell line and clinical samples containing FLT3-ITDs, dPCR-HSAFM returned the expected variant length and variant allele frequency, down to 5% variant samples. As a high-throughput method with single-molecule resolution, dPCR-HSAFM thus represents an advance in HSAFM analysis and a powerful tool for the diagnosis of length polymorphisms.

Artemisinin-type drugs for the treatment of hematological malignancies

Qinghaosu, known as artemisinin (ARS), has been for over two millennia, one of the most common herbs prescribed in traditional Chinese medicine (TCM). ARS was developed as an antimalarial drug and currently belongs to the established standard treatments of malaria as a combination therapy worldwide. In addition to the antimalarial bioactivity of ARS, anticancer activities have been shown both in vitro and in vivo. Like other natural products, ARS acts in a multi-specific manner also against hematological malignancies. The chemical structure of ARS is a sesquiterpene lactone, which contains an endoperoxide bridge essential for activity. The main mechanism of action of ARS and its derivatives (artesunate, dihydroartemisinin, artemether) toward leukemia, multiple myeloma, and lymphoma cells comprises oxidative stress response, inhibition of proliferation, induction of various types of cell death as apoptosis, autophagy, ferroptosis, inhibition of angiogenesis, and signal transducers, as NF-κB, MYC, amongst others. Therefore, new pharmaceutically active compounds, dimers, trimers, and hybrid molecules, could enhance the existing therapeutic alternatives in combating hematologic malignancies. Owing to the high potency and good tolerance without side effects of ARS-type drugs, combination therapies with standard chemotherapies could be applied in the future after further clinical trials in hematological malignancies.

LINC00963 facilitates acute myeloid leukemia development by modulating miR-608/MMP-15

Despite continuous improvements of AML therapy, the prognosis of AML patients remains unsatisfactory. Recently, lncRNAs have been reported to participate in the development of AML. Our data demonstrated that MMP15 and LINC00963 were upregulated and miR-608 was decreased in AML cells (THP-1, HL-60, HEL and MOLM-13) compared to HS-5 cells. RT-qPCR results showed that LINC00963 levels were higher in the serum and bone marrow of AML cases than in controls. Moreover, overexpression of LINC00963 promoted AML cell growth and EMT progression in both THP-1 and HL-60 cells. Furthermore, miR-608 levels were downregulated in the serum and bone marrow of AML cases compared with controls, and Pearson's correlation analysis indicated that LINC00963 was negatively correlated with miR-608 in the serum and bone marrow of AML samples. In addition, we demonstrated that LINC00963 sponged miR-608 expression and that MMP-15 was a target of miR-608 in AML cells. Finally, rescue experiments indicated that ectopic expression of LINC00963 accelerated cell growth and EMT development by modulating MMP-15. These data demonstrated that LINC00963 acted as an oncogene and may be a potential target for AML treatment.