Hypomethylating agent alters the immune microenvironment in acute myeloid leukaemia (AML) and enhances the immunogenicity of a dendritic cell/AML vaccine

Autophagy degrades immunogenic endogenous retroelements induced by 5-azacytidine in acute myeloid leukemia

The hypomethylating agent 5-azacytidine (AZA) is the first-line treatment for AML patients unfit for intensive chemotherapy. The effect of AZA results in part from T-cell cytotoxic responses against MHC-I-associated peptides (MAPs) deriving from hypermethylated genomic regions such as cancer-testis antigens (CTAs), or endogenous retroelements (EREs). However, evidence supporting higher ERE MAPs presentation after AZA treatment is lacking. Therefore, using proteogenomics, we examined the impact of AZA on the repertoire of MAPs and their source transcripts. AZA-treated AML upregulated both CTA and ERE transcripts, but only CTA MAPs were presented at greater levels. Upregulated ERE transcripts triggered innate immune responses against double-stranded RNAs but were degraded by autophagy, and not processed into MAPs. Autophagy resulted from the formation of protein aggregates caused by AZA-dependent inhibition of DNMT2. Autophagy inhibition had an additive effect with AZA on AML cell proliferation and survival, increased ERE levels, increased pro-inflammatory responses, and generated immunogenic tumor-specific ERE-derived MAPs. Finally, autophagy was associated with a lower abundance of CD8+ T-cell markers in AML patients expressing high levels of EREs. This work demonstrates that AZA-induced EREs are degraded by autophagy and shows that inhibiting autophagy can improve the immune recognition of AML blasts in treated patients.

Immunotherapy of mesothelioma: the evolving change of a long-standing therapeutic dream

Pleural mesothelioma (PM) is an aggressive and rare disease, characterized by a very poor prognosis. For almost two decades, the world standard treatment regimen for unresectable PM has consisted of a platinum-based drug plus pemetrexed, leading to an overall survival of approximately 12 months. The dramatic therapeutic scenario of PM has recently changed with the entry into the clinic of immune checkpoint inhibition, which has proven to be an effective approach to improve the survival of PM patients. The aim of the present review is to provide a comprehensive overview of the most promising immunotherapeutic-based strategies currently under investigation for advanced PM.

Targeting one-carbon metabolism for cancer immunotherapy

BACKGROUND

One-carbon (1C) metabolism is a metabolic network that plays essential roles in biological reactions. In 1C metabolism, a series of nutrients are used to fuel metabolic pathways, including nucleotide metabolism, amino acid metabolism, cellular redox defence and epigenetic maintenance. At present, 1C metabolism is considered the hallmark of cancer. The 1C units obtained from the metabolic pathways increase the proliferation rate of cancer cells. In addition, anticancer drugs, such as methotrexate, which target 1C metabolism, have long been used in the clinic. In terms of immunotherapy, 1C metabolism has been used to explore biomarkers connected with immunotherapy response and immune-related adverse events in patients.

METHODS

We collected numerous literatures to explain the roles of one-carbon metabolism in cancer immunotherapy.

RESULTS

In this review, we focus on the important pathways in 1C metabolism and the function of 1C metabolism enzymes in cancer immunotherapy. Then, we summarise the inhibitors acting on 1C metabolism and their potential application on cancer immunotherapy. Finally, we provide a viewpoint and conclusion regarding the opportunities and challenges of targeting 1C metabolism for cancer immunotherapy in clinical practicability in the future.

CONCLUSION

Targeting one-carbon metabolism is useful for cancer immunotherapy.

Randomized Phase II Trial of Dendritic Cell/Myeloma Fusion Vaccine with Lenalidomide Maintenance after Upfront Autologous Hematopoietic Cell Transplantation for Multiple Myeloma: BMT CTN 1401

PURPOSE

Vaccination with dendritic cell (DC)/multiple myeloma (MM) fusions has been shown to induce the expansion of circulating multiple myeloma-reactive lymphocytes and consolidation of clinical response following autologous hematopoietic cell transplant (auto-HCT).

PATIENTS AND METHODS

In this randomized phase II trial (NCT02728102), we assessed the effect of DC/MM fusion vaccination, GM-CSF, and lenalidomide maintenance as compared with control arms of GM-CSF and lenalidomide or lenalidomide maintenance alone on clinical response rates and induction of multiple myeloma-specific immunity at 1-year posttransplant.

RESULTS

The study enrolled 203 patients, with 140 randomized posttransplantation. Vaccine production was successful in 63 of 68 patients. At 1 year, rates of CR were 52.9% (vaccine) and 50% (control; P = 0.37, 80% CI 44.5%, 61.3%, and 41.6%, 58.4%, respectively), and rates of VGPR or better were 85.3% (vaccine) and 77.8% (control; P = 0.2). Conversion to CR at 1 year was 34.8% (vaccine) and 27.3% (control; P = 0.4). Vaccination induced a statistically significant expansion of multiple myeloma-reactive T cells at 1 year compared with before vaccination (P = 0.024) and in contrast to the nonvaccine arm (P = 0.026). Single-cell transcriptomics revealed clonotypic expansion of activated CD8 cells and shared dominant clonotypes between patients at 1-year posttransplant.

CONCLUSIONS

DC/MM fusion vaccination with lenalidomide did not result in a statistically significant increase in CR rates at 1 year posttransplant but was associated with a significant increase in circulating multiple myeloma-reactive lymphocytes indicative of tumor-specific immunity. Site-specific production of a personalized cell therapy with centralized product characterization was effectively accomplished in the context of a multicenter cooperative group study. See related commentary by Qazilbash and Kwak, p. 4703.

Application of Engineered Dendritic Cell Vaccines in Cancer Immunotherapy: Challenges and Opportunities

OPINION STATEMENT

The primary objective of this study is to evaluate the effectiveness of cancer vaccines containing genetically modified dendritic cells (DCs) in inducing transformational immune responses. This paper sheds considerable light on DCs' function in advancing treatment techniques. This objective is achieved by thoroughly analyzing the many facets of DCs and their strategic integration into cancer treatment. Due to their role as immune response regulators, DCs can potentially enhance cancer treatment strategies. DCs have the potential to revolutionize immunotherapy, as shown by a comprehensive analysis of their numerous characteristics. The review deftly transitions from examining the fundamentals of preclinical research to delving into the complexities of clinical implementation while acknowledging the inherent challenges in translating DC vaccine concepts into tangible progress. The analysis also emphasizes the potential synergistic outcomes that can be achieved by combining DC vaccines with established pharmaceuticals, thereby emphasizing the importance of employing a holistic approach to enhance treatment efficacy. Despite the existence of transformative opportunities, advancement is hindered by several obstacles. The exhaustive analysis of technical complexities, regulatory dynamics, and upcoming challenges provides valuable insights for overcoming obstacles requiring strategic navigation to incorporate DC vaccines successfully. This document provides a comprehensive analysis of the developments in DC-based immunotherapy, concentrating on its potential to transform cancer therapy radically.

Progress of research on PD-1/PD-L1 in leukemia

Leukemia cells prevent immune system from clearing tumor cells by inducing the immunosuppression of the bone marrow (BM) microenvironment. In recent years, further understanding of the BM microenvironment and immune landscape of leukemia has resulted in the introduction of several immunotherapies, including checkpoint inhibitors, T-cell engager, antibody drug conjugates, and cellular therapies in clinical trials. Among them, the programmed cell death protein 1 (PD-1)/programmed death-ligand 1 (PD-L1) axis is a significant checkpoint for controlling immune responses, the PD-1 receptor on tumor-infiltrating T cells is bound by PD-L1 on leukemia cells. Consequently, the activation of tumor reactive T cells is inhibited and their apoptosis is promoted, preventing the rejection of the tumor by immune system and thus resulting in the occurrence of immune tolerance. The PD-1/PD-L1 axis serves as a significant mechanism by which tumor cells evade immune surveillance, and PD-1/PD-L1 checkpoint inhibitors have been approved for the treatment of lymphomas and varieties of solid tumors. However, the development of drugs targeting PD-1/PD-L1 in leukemia remains in the clinical-trial stage. In this review, we tally up the basic research and clinical trials on PD-1/PD-L1 inhibitors in leukemia, as well as discuss the relevant toxicity and impacts of PD-1/PD-L1 on other immunotherapies such as hematopoietic stem cell transplantation, bi-specific T-cell engager, chimeric antigen receptor T-cell immunotherapy.

Preclinical Validation of an Advanced Therapy Medicinal Product Based on Cytotoxic T Lymphocytes Specific for Mutated Nucleophosmin (NPM1mut) for the Treatment of NPM1mut-Acute Myeloid Leukemia

Acute myeloid leukemia (AML) with nucleophosmin (NPM1) genetic mutations is the most common subtype in adult patients. Refractory or relapsed disease in unfit patients or after allogeneic hematopoietic stem cell transplantation (allo-HSCT) has a poor prognosis. NPM1-mutated protein, stably expressed on tumor cells but not on normal tissues, may serve as an ideal target for NPM1-mutated AML immunotherapy. The study aim was to investigate the feasibility of producing mutated-NPM1-specific cytotoxic T cells (CTLs) suitable for somatic cell therapy to prevent or treat hematologic relapse in patients with NPM1-mutated AML. T cells were expanded or primed from patient or donor peripheral blood mononuclear cells by NPM1-mutated protein-derived peptides, and tested for leukemia antigen-targeted cytotoxic activity, cytokine production and hematopoietic precursor inhibitory effect. We found that mutated-NPM1-specific CTLs, displaying specific cytokine production and high-level cytotoxicity against patients' leukemia blasts, and limited inhibitory activity in clonogenic assays, could be obtained from both patients and donors. The polyfunctional mutated-NPM1-specific CTLs included both CD8+ and CD4+ T cells endowed with strong lytic capacity. Our results suggest that mutated-NPM1-targeted CTLs may be a useful therapeutic option to control low-tumor burden relapse following conventional chemotherapy in older NPM1-mutated AML patients or eradicate persistent MRD after HSCT.

Decitabine in combination with fludarabine and cyclophosphamide as a lymphodepletion regimen followed by CD19/CD22 bispecific targeted CAR T-cell therapy significantly improves survival in relapsed/refractory B-ALL patients

Relapse is a major limitation of chimeric antigen receptor (CAR) T-cell therapy. Here, we speculated that decitabine (DAC) in combination with fludarabine and cyclophosphamide (FC) as a lymphodepletion regimen may improve the efficacy of CD19/CD22 CAR T-cell therapy. Fourteen of 26 patients with relapsed/refractory B cell acute lymphoblastic leukemia (r/r B-ALL) without remission before lymphodepletion treatment were treated with DAC (total dose 100 mg/m² in 3 days) followed by the FC regimen (DAC group), while twelve patients received the FC regimen (CON group). On Day 28 after CAR T-cells infusion, no significant differences in complete remission (CR) and minimal residual disease negative CR rates were found between both groups. However, there were significant differences in overall survival (OS) and leukemia-free survival (LFS) between two groups: 3-year OS, 92.3% (DAC) versus 41.7% (CON), P = 0.005 and 3-year LFS, 92.9% (DAC) versus 27.3% (CON), P < 0.001. There was no significant difference in the incidence of cytokine release syndrome between both groups. Median time to platelet and neutrophil counts recovery was similar in both groups. All adverse events were reversible and manageable. In conclusion, DAC in combination with the FC lymphodepletion regimen may be a new treatment option that can improve the efficacy of CAR T-cell therapy in r/r B-ALL.

Immune dysregulation in multiple myeloma: the current and future role of cell-based immunotherapy

Immune dysregulation is a hallmark of clinically active multiple myeloma (MM). Interactions between malignant clonal cells and immune cells within the bone marrow microenvironment are associated with the formation of a milieu favorable to tumor progression. IL-10, TGF-β and other immunoregulatory pathways are upregulated, promoting angiogenesis, tumor cell survival and inhibition of the native immune response. Transcriptomic evaluation of the bone marrow microenvironment reveals polarization of the T cell repertoire towards exhaustion and predominance of accessory cells with immunosuppressive qualities. These changes facilitate the immune escape of tumor cells and functional deficiencies that manifest as an increased risk of infection and a reduction in response to vaccinations. Immunotherapy with Chimeric Antigen Receptor (CAR) T cells and other cellular-based approaches have transformed outcomes for patients with advanced MM. Characterization of the immune milieu and identification of biomarkers predictive of treatment response are essential to increasing durability and allowing for the incorporation of novel strategies such as cancer vaccines. This paper will review the current use of cancer vaccines and CAR T cell therapy in MM as well as potential opportunities to expand and improve the application of these platforms.

Identification of tumor antigens and immune subtypes of acute myeloid leukemia for mRNA vaccine development

BACKGROUND

Acute myeloid leukemia (AML) is a highly aggressive hematological malignancy, and there has not been any significant improvement in therapy of AML over the past several decades. The mRNA vaccines have become a promising strategy against multiple cancers, however, its application on AML remains undefined. In this study, we aimed to identify novel antigens for developing mRNA vaccines against AML and explore the immune landscape of AML to select appropriate patients for vaccination.

METHODS

Genomic data and gene mutation data were retrieved from TCGA, GEO and cBioPortal, respectively. GEPIA2 was used to analyze differentially expressed genes. The single cell RNA-seq database Tumor Immune Single-cell Hub (TISCH) was used to explore the association between the potential tumor antigens and the infiltrating immune cells in the bone marrow. Consensus clustering analysis was applied to identify distinct immune subtypes. The correlation between the abundance of antigen presenting cells and the expression level of antigens was evaluated using Spearman correlation analysis. The characteristics of the tumor immune microenvironment in each subtype were investigated based on single-sample gene set enrichment analysis.

RESULTS

Five potential tumor antigens were identified for mRNA vaccine from the pool of overexpressed and mutated genes, including CDH23, LRP1, MEFV, MYOF and SLC9A9, which were associated with infiltration of antigen-presenting immune cells (APCs). AML patients were stratified into two immune subtypes Cluster1 (C1) and Cluster2 (C2), which were characterized by distinct molecular and clinical features. C1 subtype demonstrated an immune-hot and immunosuppressive phenotype, while the C1 subtype had an immune-cold phenotype. Furthermore, the two immune subtype showed remarkably different expression of immune checkpoints, immunogenic cell death modulators and human leukocyte antigens.

CONCLUSION

CDH23, LRP1, MEFV, MYOF and SLC9A9 were potential antigens for developing AML mRNA vaccine, and AML patients in immune subtype 1 were suitable for vaccination.

CD86 Is Associated with Immune Infiltration and Immunotherapy Signatures in AML and Promotes Its Progression

Background

Cluster of differentiation 86 (CD86), also known as B7-2, is a molecule expressed on antigen-presenting cells that provides the costimulatory signals required for T cell activation and survival. CD86 binds to two ligands on the surface of T cells: the antigen CD28 and cytotoxic T lymphocyte-associated protein 4 (CTLA-4). By binding to CD28, CD86-together with CD80-promotes the participation of T cells in the antigen presentation process. However, the interrelationships among CD86, immunotherapy, and immune infiltration in acute myeloid leukemia (AML) are unclear.

Methods

The immunological effects of CD86 in various cancers (including on chemokines, immunostimulators, MHC, and receptors) were evaluated through a pan-cancer analysis using TCGA and GEO databases. The relationship between CD86 expression and mononucleotide variation, gene copy number variation, methylation, immune checkpoint blockers (ICBs), and T-cell inflammation score in AML was subsequently examined. ESTIMATE and limma packages were used to identify genes at the intersection of CD86 with StromalScore and ImmuneScore. Subsequently, GO/KEGG and PPI network analyses were performed. The immune risk score (IRS) model was constructed, and the validation set was used for verification. The predictive value was compared with the TIDE score.

Results

CD86 was overexpressed in many cancers, and its overexpression was associated with a poor prognosis. CD86 expression was positively correlated with the expression of CTLA4, PDCD1LG2, IDO1, HAVCR2, and other genes and negatively correlated with CD86 methylation. The expression of CD86 in AML cell lines was detected by QRT-PCR and Western blot, and the results showed that CD86 was overexpressed in AML cell lines. Immune infiltration assays showed that CD86 expression was positively correlated with CD8 T cell, Dendritic cell, macrophage, NK cell, and Th1_cell and also with immune examination site, immune regulation, immunotherapy response, and TIICs. ssGSEA showed that CD86 was enriched in immune-related pathways, and CD86 expression was correlated with mutations in the genes RB1, ERBB2, and FANCC, which are associated with responses to radiotherapy and chemotherapy. The IRS score performed better than the TIDE website score.

Conclusion

CD86 appears to participate in immune invasion in AML and is an important player in the tumor microenvironment in this malignancy. At the same time, the IRS score developed by us has a good effect and may provide some support for the diagnosis of AML. Thus, CD86 may serve as a potential target for AML immunotherapy.

A perspective of immunotherapy for acute myeloid leukemia: Current advances and challenges

During the last decade, the underlying pathogenic mechanisms of acute myeloid leukemia (AML) have been the subject of extensive study which has considerably increased our understanding of the disease. However, both resistance to chemotherapy and disease relapse remain the principal obstacles to successful treatment. Because of acute and chronic undesirable effects frequently associated with conventional cytotoxic chemotherapy, consolidation chemotherapy is not feasible, especially for elderly patients, which has attracted a growing body of research to attempt to tackle this problem. Immunotherapies for acute myeloid leukemia, including immune checkpoint inhibitors, monoclonal antibodies, dendritic cell (DC) vaccines, together with T-cell therapy based on engineered antigen receptor have been developed recently. Our review presents the recent progress in immunotherapy for the treatment of AML and discusses effective therapies that have the most potential and major challenges.

5-Azacytidine-Mediated Modulation of the Immune Microenvironment in Murine Acute Myeloid Leukemia

Cancer cells accumulate epigenetic modifications that allow escape from intrinsic and extrinsic surveillance mechanisms. In the case of acute myeloid leukemias (AML) and myelodysplastic syndromes, agents that disrupt chromatin structure, namely hypomethylating agents (HMAs), have shown tremendous promise as an alternate, milder treatment option for older, clinically non-fit patients. HMAs reprogram the epigenetic landscape in tumor cells through the reversal of DNA hypermethylation. Therapeutic effects resulting from these epigenetic changes are incredibly effective, sometimes resulting in complete remissions, but are frequently lost due to primary or acquired resistance. In this study, we describe syngeneic murine leukemias that are responsive to the HMA 5-azacytidine (5-Aza), as determined by augmented expression of a transduced luciferase reporter. We also found that 5-Aza treatment re-established immune-related transcript expression, suppressed leukemic burden and extended survival in leukemia-challenged mice. The effects of 5-Aza treatment were short-lived, and analysis of the immune microenvironment reveals possible mechanisms of resistance, such as simultaneous increase in immune checkpoint protein expression. This represents a model system that is highly responsive to HMAs and recapitulates major therapeutic outcomes observed in human leukemia (relapse) and may serve as a pre-clinical tool for studying acquired resistance and novel treatment combinations.

Hsa_circ_0015278 Regulates FLT3-ITD AML Progression via Ferroptosis-Related Genes

AML with the FLT3-ITD mutation seriously threatens human health. The mechanism by which circRNAs regulate the pathogenesis of FLT3-ITD mutant-type AML through ferroptosis-related genes (FerRGs) remains unclear. Differentially expressed circRNAs and mRNAs were identified from multiple integrated data sources. The target miRNAs and mRNAs of the circRNAs were predicted using various databases. The PPI network, ceRNA regulatory network, GO, and KEGG enrichment analyses were performed. The "survival" and the "pROC" R packages were used for K-M and ROC analysis, respectively. GSEA, immune infiltration analysis, and clinical subgroup analysis were performed. Finally, circRNAs were validated by Sanger sequencing and qRT-PCR. In our study, 77 DECircs-1 and 690 DECircs-2 were identified. Subsequently, 11 co-up-regulated DECircs were obtained by intersecting DECircs-1 and DECircs-2. The target miRNAs of the circRNAs were screened by CircInteractome, circbank, and circAtlas. Utilizing TargetScan, ENCORI, and miRWalk, the target mRNAs of the miRNAs were uncovered. Ultimately, 73 FerRGs were obtained, and the ceRNA regulatory network was constructed. Furthermore, MAPK3 and CD44 were significantly associated with prognosis. qRT-PCR results confirmed that has_circ_0015278 was significantly overexpressed in FLT3-ITD mutant-type AML. In summary, we constructed the hsa_circ_0015278/miRNAs/FerRGs signaling axis, which provides new insight into the pathogenesis and therapeutic targets of AML with FLT3-ITD mutation.

Multiplexed engineering and precision gene editing in cellular immunotherapy

The advent of cellular immunotherapy in the clinic has entirely redrawn the treatment landscape for a growing number of human cancers. Genetically reprogrammed immune cells, including chimeric antigen receptor (CAR)-modified immune effector cells as well as T cell receptor (TCR) therapy, have demonstrated remarkable responses across different hard-to-treat patient populations. While these novel treatment options have had tremendous success in providing long-term remissions for a considerable fraction of treated patients, a number of challenges remain. Limited in vivo persistence and functional exhaustion of infused immune cells as well as tumor immune escape and on-target off-tumor toxicities are just some examples of the challenges which restrain the potency of today's genetically engineered cell products. Multiple engineering strategies are being explored to tackle these challenges.The advent of multiplexed precision genome editing has in recent years provided a flexible and highly modular toolkit to specifically address some of these challenges by targeted genetic interventions. This class of next-generation cellular therapeutics aims to endow engineered immune cells with enhanced functionality and shield them from immunosuppressive cues arising from intrinsic immune checkpoints as well as the hostile tumor microenvironment (TME). Previous efforts to introduce additional genetic modifications into immune cells have in large parts focused on nuclease-based tools like the CRISPR/Cas9 system or TALEN. However, nuclease-inactive platforms including base and prime editors have recently emerged and promise a potentially safer route to rewriting genetic sequences and introducing large segments of transgenic DNA without inducing double-strand breaks (DSBs). In this review, we discuss how these two exciting and emerging fields-cellular immunotherapy and precision genome editing-have co-evolved to enable a dramatic expansion in the possibilities to engineer personalized anti-cancer treatments. We will lay out how various engineering strategies in addition to nuclease-dependent and nuclease-inactive precision genome editing toolkits are increasingly being applied to overcome today's limitations to build more potent cellular therapeutics. We will reflect on how novel information-rich unbiased discovery approaches are continuously deepening our understanding of fundamental mechanisms governing tumor biology. We will conclude with a perspective of how multiplexed-engineered and gene edited cell products may upend today's treatment paradigms as they evolve into the next generation of more potent cellular immunotherapies.

Natural killer cells in antitumour adoptive cell immunotherapy

Natural killer (NK) cells comprise a unique population of innate lymphoid cells endowed with intrinsic abilities to identify and eliminate virally infected cells and tumour cells. Possessing multiple cytotoxicity mechanisms and the ability to modulate the immune response through cytokine production, NK cells play a pivotal role in anticancer immunity. This role was elucidated nearly two decades ago, when NK cells, used as immunotherapeutic agents, showed safety and efficacy in the treatment of patients with advanced-stage leukaemia. In recent years, following the paradigm-shifting successes of chimeric antigen receptor (CAR)-engineered adoptive T cell therapy and the advancement in technologies that can turn cells into powerful antitumour weapons, the interest in NK cells as a candidate for immunotherapy has grown exponentially. Strategies for the development of NK cell-based therapies focus on enhancing NK cell potency and persistence through co-stimulatory signalling, checkpoint inhibition and cytokine armouring, and aim to redirect NK cell specificity to the tumour through expression of CAR or the use of engager molecules. In the clinic, the first generation of NK cell therapies have delivered promising results, showing encouraging efficacy and remarkable safety, thus driving great enthusiasm for continued innovation. In this Review, we describe the various approaches to augment NK cell cytotoxicity and longevity, evaluate challenges and opportunities, and reflect on how lessons learned from the clinic will guide the design of next-generation NK cell products that will address the unique complexities of each cancer.

The pyroptosis-related gene signature predicts prognosis and reveals characterization of the tumor immune microenvironment in acute myeloid leukemia

Background: Pyroptosis is a novel inflammatory form of programmed cell death and a prospective target for cancer therapy. Nevertheless, little is known about the association between pyroptosis-related genes (PRGs) and acute myeloid leukemia (AML) prognosis. Herein, we systematically investigated the specific functions and clinical prognostic value of multiple PRGs in AML.

Methods: Univariate and LASSO Cox regression analyses based on TCGA and GTEx databases were used to generate the PRG signature, whose predictive efficacy of survival was evaluated using survival analysis, ROC, univariate and multivariate Cox analyses as well as subgroup analysis. The BeatAML cohort was used for data validation. The association between risk score and immune cell infiltration, HLA, immune checkpoints, cancer stem cell (CSC), tumor mutation burden (TMB), and therapeutic drug sensitivity were also analyzed.

Results: Six -PRG signatures, namely, CASP3, ELANE, GSDMA, NOD1, PYCARD, and VDR were generated. The high-risk score represented a poorer prognosis and the PRG risk score was also validated as an independent predictor of prognosis. A nomogram including the cytogenetic risk, age, and risk score was constructed for accurate prediction of 1-, 3-, and 5-year survival probabilities. Meanwhile, this risk score was significantly associated with the tumor immune microenvironment (TIME). A high-risk score is characterized by high immune cell infiltration, HLA, and immune checkpoints, as well as low CSC and TMB. In addition, patients with low-risk scores presented significantly lower IC50 values for ATRA, cytarabine, midostaurin, doxorubicin, and etoposide.

Conclusion: Our findings might contribute to further understanding of PRGs in the prognosis and development of AML and provide novel and reliable biomarkers for its precise prevention and treatment.

Epi-immunotherapy for cancers: rationales of epi-drugs in combination with immunotherapy and advances in clinical trials

Over the last two decades, several epi-drugs, immune checkpoint inhibitors (ICIs) and adoptive cell therapies have received clinical approval for use in certain types of cancer. However, monotherapy with epi-drugs or ICIs has shown limited efficacy in most cancer patients. Epigenetic agents have been shown to regulate the crosstalk between the tumor and host immunity to alleviate immune evasion, suggesting that epi-drugs can potentially synergize with immunotherapy. In this review, we discuss recent insights into the rationales of incorporating epigenetic therapy into immunotherapy, called epi-immunotherapy, and focus on an update of current clinical trials in both hematological and solid malignancies. Furthermore, we outline the future challenges and strategies in the field of cancer epi-immunotherapy.

Non-cleavable hinge enhances avidity and expansion of CAR-T cells for acute myeloid leukemia

Chimeric antigen receptor (CAR) T cell therapy is effective in lymphoid malignancies, but there has been limited data in myeloid cancers. Here, we start with a CD27-based CAR to target CD70 ("native") in acute myeloid leukemia (AML), and we find modest efficacy in vivo, consistent with prior reports. We then use orthogonal approaches to increase binding on both the tumor and CAR-T cell sides of the immune synapse: a pharmacologic approach (azacitidine) to increase antigen density of CD70 in myeloid tumors, and an engineering approach to stabilize binding of the CAR to CD70. To accomplish the latter, we design a panel of hinge-modified regions to mitigate cleavage of the extracellular portion of CD27. Our CD8 hinge and transmembrane-modified CD70 CAR-T cells are less prone to cleavage, have enhanced binding avidity, and increased expansion, leading to more potent in vivo activity. This enhanced CD70-targeted CAR is a promising candidate for further clinical development.

Comprehensive Analysis of N6-Methyladenosine-Related Long Noncoding RNA Prognosis of Acute Myeloid Leukemia and Immune Cell Infiltration

N6-Methyladenosine-related long noncoding RNAs play an essential role in many cancers’ development. However, the relationship between m6A-related lncRNAs and acute myelogenous leukemia (AML) prognosis remains unclear. We systematically analyzed the association of m6A-related lncRNAs with the prognosis and tumor immune microenvironment (TME) features using the therapeutically applicable research to generate effective treatment (TARGET) database. We screened 315 lncRNAs associated with AML prognosis and identified nine key lncRNAs associated with m6A by the LASSO Cox analysis. A model was established based on these nine lncRNAs and the predictive power was explored in The Cancer Genome Atlas (TCGA) database. The areas under the ROC curve of TARGET and TCGA databases for ROC at 1, 3, and 5 years are 0.701, 0.704, and 0.696, and 0.587, 0.639, and 0.685, respectively. The nomogram and decision curve analysis (DCA) showed that the risk score was more accurate than other clinical indicators in evaluating patients’ prognoses. The clusters with a better prognosis enrich the AML pathways and immune-related pathways. We also found a close correlation between prognostic m6A-related lncRNAs and tumor immune cell infiltration. LAG3 expression at the immune checkpoint was lower in the worse prognostic cluster. In conclusion, m6A-related lncRNAs partly affected AML prognosis by remodeling the TME and affecting the anticarcinogenic ability of immune checkpoints, especially LAG3 inhibitors. The prognostic model constructed with nine key m6A-related lncRNAs can provide a method to assess the prognosis of AML patients in both adults and children.

Clinical characteristics, treatment, and prognosis of 118 cases of myeloid sarcoma

Myeloid sarcoma is a rare manifestation of acute myeloid leukemia (AML) and is associated with poor overall survival (OS). The optimal treatment remains unclear. The study retrospectively evaluated 118 patients with myeloid sarcoma who were treated at the First Affiliated Hospital of Zhengzhou University from January 2010 to July 2021. All cases were diagnosed by tissue biopsy. 41 patients underwent genetic mutation analysis. The most frequent genetic mutations were KIT (16.6%), followed by TET2 (14.6%), and NRAS (14.6%). The median survival time of 118 patients was 4 months (range, 1–51 months), while the median survival time of 11 patients who received allogeneic hematopoietic stem cell transplantation (allo-HSCT) was 19 months (range, 8–51 months). 4 (36.4%) of the 11 patients experienced relapse within 1 year after transplantation. 1 patient died from a severe infection. Of the 6 surviving patients, 5 patients have received maintenance treatment with decitabine after transplantation, and all remained in a state of recurrence-free survival. Patients with myeloid sarcoma have a very unfavorable outcome. Allo-HSCT is an effective treatment option. Recurrence remains the main cause of transplant failure. Maintenance treatment with decitabine after transplantation can prolong the recurrence-free survival time, although these results must be verified in a study with expanded sample size.

Research progress on dendritic cell vaccines in cancer immunotherapy

Dendritic cell (DC) vaccines induce specific immune responses that can selectively eliminate target cells. In recent years, many studies have been conducted to explore DC vaccination in the treatment of hematological malignancies, including acute myeloid leukemia and myelodysplastic syndromes, as well as other nonleukemia malignancies. There are at least two different strategies that use DCs to promote antitumor immunity: in situ vaccination and canonical vaccination. Monocyte-derived DCs (mo-DCs) and leukemia-derived DCs (DCleu) are the main types of DCs used in vaccines for AML and MDS thus far. Different cancer-related molecules such as peptides, recombinant proteins, apoptotic leukemic cells, whole tumor cells or lysates and DCs/DCleu containing a vaster antigenic repertoire with RNA electroporation, have been used as antigen sources to load DCs. To enhance DC vaccine efficacy, new strategies, such as combination with conventional chemotherapy, monospecific/bispecific antibodies and immune checkpoint-targeting therapies, have been explored. After a decade of trials and tribulations, much progress has been made and much promise has emerged in the field. In this review we summarize the recent advances in DC vaccine immunotherapy for AML/MDS as well as other nonleukemia malignancies.

Acute myeloid leukemia cell membrane-coated nanoparticles for cancer vaccination immunotherapy

Cancer vaccines are promising treatments to prevent relapse after chemotherapy in acute myeloid leukemia (AML) patients, particularly for those who cannot tolerate intensive consolidation therapies. Here, we report the development of an AML cell membrane-coated nanoparticle (AMCNP) vaccine platform, in which immune-stimulatory adjuvant-loaded nanoparticles are coated with leukemic cell membrane material. This AMCNP vaccination strategy stimulates leukemia-specific immune responses by co-delivering membrane-associated antigens along with adjuvants to antigen-presenting cells. To demonstrate that this AMCNP vaccine enhances leukemia-specific antigen presentation and T cell responses, we modified a murine AML cell line to express membrane-bound chicken ovalbumin as a model antigen. AMCNPs were efficiently acquired by antigen-presenting cells in vitro and in vivo and stimulated antigen cross-presentation. Vaccination with AMCNPs significantly enhanced antigen-specific T cell expansion and effector function compared with control vaccines. Prophylactic vaccination with AMCNPs enhanced cellular immunity and protected against AML challenge. Moreover, in an AML post-remission vaccination model, AMCNP vaccination significantly enhanced survival in comparison to vaccination with whole leukemia cell lysates. Collectively, AMCNPs retained AML-specific antigens, elicited enhanced antigen-specific immune responses, and provided therapeutic benefit against AML challenge.

Epigenetic Immune Remodeling of Mesothelioma Cells: A New Strategy to Improve the Efficacy of Immunotherapy

Malignant pleural mesothelioma (MPM) is an aggressive malignancy with a severe prognosis, and with a long-standing need for more effective therapeutic approaches. However, treatment with immune checkpoint inhibitors is becoming an increasingly effective strategy for MPM patients. In this scenario, epigenetic modifications may negatively regulate the interplay between immune and malignant cells within the tumor microenvironment, thus contributing to the highly immunosuppressive contexture of MPM that may limit the efficacy of immunotherapy. Aiming to further improve prospectively the clinical efficacy of immunotherapeutic approaches in MPM, we investigated the immunomodulatory potential of different classes of epigenetic drugs (i.e., DNA hypomethylating agent (DHA) guadecitabine, histone deacetylase inhibitors VPA and SAHA, or EZH2 inhibitors EPZ-6438) in epithelioid, biphasic, and sarcomatoid MPM cell lines, by cytofluorimetric and real-time PCR analyses. We also characterized the effects of the DHA, guadecitabine, on the gene expression profiles (GEP) of the investigated MPM cell lines by the nCounter platform. Among investigated drugs, exposure of MPM cells to guadecitabine, either alone or in combination with VPA, SAHA and EPZ-6438 demonstrated to be the main driver of the induction/upregulation of immune molecules functionally crucial in host-tumor interaction (i.e., HLA class I, ICAM-1 and cancer testis antigens) in all three MPM subtypes investigated. Additionally, GEP demonstrated that treatment with guadecitabine led to the activation of genes involved in several immune-related functional classes mainly in the sarcomatoid subtype. Furthermore, among investigated MPM subtypes, DHA-induced CDH1 expression that contributes to restoring the epithelial phenotype was highest in sarcomatoid cells. Altogether, our results contribute to providing the rationale to develop new epigenetically-based immunotherapeutic approaches for MPM patients, potentially tailored to the specific histologic subtypes.

Dipetidyl peptidase-4 and transferrin receptor serve as prognostic biomarkers for acute myeloid leukemia

Background

Acute myeloid leukemia (AML) is the most common hematological malignancy in adult patients. Ferroptosis-related signatures have been shown to act as regulators of the progression of multiple cancer types, but the role of ferroptosis in AML remains to be elucidated. We performed the present study to preliminarily investigate the roles of ferroptosis-related genes (FRGs) in AML.

Methods

The transcriptome data of AML patients was downloaded from The Cancer Genome Atlas (TCGA) and the transcriptome data of normal samples was obtained from the Genotype-Tissue Expression (GTEx) database. FRGs were selected via public articles. Expression levels of FRGs between AML and normal samples were analyzed. The prognostic model based on FRGs was constructed via lasso regression. The expression levels and prognostic role of FRGs were identified from the risk model. We also performed validation experiments to verify the expression levels of the final selected genes via immunohistochemistry, polymerase chain reaction (PCR), and RNA-seq. Finally, we explored the associations between immune infiltration, drug sensitivity, and the selected FRGs.

Results

The transcriptome data of 151 AML samples were retrieved from TCGA and 70 bone marrow normal samples were retrieved from the GTEx database. Additionally, 23 FRGs were collected from the published articles. There were 22 differentially expressed FRGs, and among them, dipetidyl peptidase-4 (DPP4) (P= 0.011, HR =1.504), GPX4 (P=0.055, HR =1.569), LPCAT3 (P<0.001, HR =2.243), SLC7A11 (P=0.012, HR =2.243), and transferrin receptor (TFRC) (P=0.029, 0.774) had a significant influence on the prognosis of AML patients via lasso regression. The area under the curve (AUC) values of the 1-, 3-, and 5-year receiver operating characteristic (ROC) curves of the FRG signatures indicated that this model is novel and effective method for predicting the prognosis of AML patients. DPP4 (P<0.001) was overexpressed while LPCAT3 (P<0.001), TFRC (P<0.001), GPX4 (P<0.001), and SLC7A11 (P<0.001) were downregulated, further validation experiment results indicated that DPP4 was significantly downregulated but TFRC was upregulated in AML samples. Dysregulation of DPP4 and TFRC influence numbers of chemotherapy regimens sensitivity.

Conclusions

DPP4 and TFRC act as biomarkers for predicting and diagnosing AML, and their expression levels also have significant correlations with drug resistance in AML.

Immunity in acute myeloid leukemia: Where the immune response and targeted therapy meet

Acute myeloid leukemia (AML) is a highly aggressive disease with high relapse and mortality rates. Recent years have shown a surge in novel therapeutic development for AML, both in clinical and preclinical stages. These developments include targeted therapies based on AML-specific molecular signatures as well as more general immune modulation and vaccination studies. In this review, we will explore the evolving arena of AML therapy and suggest some intriguing connections between immune system modulation and targeted therapy. Improved understanding of the immune system involvement in various stages of the disease and the crosstalk between immune effectors, targeted therapy, and AML cells can provide a better framework for designing the next generation of AML therapies.

Resistance to Hypomethylating Agents in Myelodysplastic Syndrome and Acute Myeloid Leukemia From Clinical Data and Molecular Mechanism

The nucleoside analogs decitabine (5-AZA-dC) and azacitidine (5-AZA) have been developed as targeted therapies to reverse DNA methylation in different cancer types, and they significantly improve the survival of patients who are not suitable for traditional intensive chemotherapies or other treatment regimens. However, approximately 50% of patients have a response to hypomethylating agents (HMAs), and many patients have no response originally or in the process of treatment. Even though new combination regimens have been tested to overcome the resistance to 5-AZA-dC or 5-AZA, only a small proportion of patients benefited from these strategies, and the outcome was very poor. However, the mechanisms of the resistance remain unknown. Some studies only partially described management after failure and the mechanisms of resistance. Herein, we will review the clinical and molecular signatures of the HMA response, alternative treatment after failure, and the causes of resistance in hematological malignancies.

Molecular Targeted Therapy and Immunotherapy for Myelodysplastic Syndrome

Myelodysplastic syndrome (MDS) is a heterogeneous, clonal hematological disorder characterized by ineffective hematopoiesis, cytopenia, morphologic dysplasia, and predisposition to acute myeloid leukemia (AML). Stem cell genomic instability, microenvironmental aberrations, and somatic mutations contribute to leukemic transformation. The hypomethylating agents (HMAs), azacitidine and decitabine are the standard of care for patients with higher-risk MDS. Although these agents induce responses in up to 40-60% of patients, primary or secondary drug resistance is relatively common. To improve the treatment outcome, combinational therapies comprising HMA with targeted therapy or immunotherapy are being evaluated and are under continuous development. This review provides a comprehensive update of the molecular pathogenesis and immune-dysregulations involved in MDS, mechanisms of resistance to HMA, and strategies to overcome HMA resistance.

The EHA Research Roadmap: Immune-based Therapies for Hematological Malignancies

In 2016, the European Hematology Association (EHA) published the EHA Roadmap for European Hematology Research¹ aiming to highlight achievements in the diagnostics and treatment of blood disorders, and to better inform European policy makers and other stakeholders about the urgent clinical and scientific needs and priorities in the field of hematology. Each section was coordinated by 1-2 section editors who were leading international experts in the field. In the 5 years that have followed, advances in the field of hematology have been plentiful. As such, EHA is pleased to present an updated Research Roadmap, now including 11 sections, each of which will be published separately. The updated EHA Research Roadmap identifies the most urgent priorities in hematology research and clinical science, therefore supporting a more informed, focused, and ideally a more funded future for European Hematology Research. the 11 EHA Research Roadmap sections include normal hematopoiesis; malignant lymphoid diseases; malignant myeloid diseases; anemias and related diseases; platelet disorders; blood coagulation and hemostatic disorders; transfusion medicine; infections in hematology; hematopoietic stem cell transplantation; CAR-T and Other cell-based immune therapies; and gene therapy.

HPV Infection Leaves a DNA Methylation Signature in Oropharyngeal Cancer Affecting Both Coding Genes and Transposable Elements

HPV oncoproteins can modulate DNMT1 expression and activity, and previous studies have reported both gene-specific and global DNA methylation alterations according to HPV status in head and neck cancer. However, validation of these findings and a more detailed analysis of the transposable elements (TEs) are still missing. Here we performed pyrosequencing to evaluate a 5-CpG methylation signature and Line1 methylation in an oropharyngeal squamous cell carcinoma (OPSCC) cohort. We further evaluated the methylation levels of the TEs, their correlation with gene expression and their impact on overall survival (OS) using the TCGA cohort. In our dataset, the 5-CpG signature distinguished HPV-positive and HPV-negative OPSCC with 66.67% sensitivity and 84.33% specificity. Line1 methylation levels were higher in HPV-positive cases. In the TCGA cohort, Line1, Alu and long terminal repeats (LTRs) showed hypermethylation in a frequency of 60.5%, 58.9% and 92.3%, respectively. ZNF541 and CCNL1 higher expression was observed in HPV-positive OPSCC, correlated with lower methylation levels of promoter-associated Alu and LTR, respectively, and independently associated with better OS. Based on our findings, we may conclude that a 5-CpG methylation signature can discriminate OPSCC according to HPV status with high accuracy and TEs are differentially methylated and may regulate gene expression in HPV-positive OPSCC.

NLRP3-activated bone marrow dendritic cells play antileukemic roles via IL-1β/Th1/IFN-γ in acute myeloid leukemia

The bone marrow microenvironment of acute myeloid leukemia (AML) characterized by immunosuppressive features fosters leukemia immune escape. Elucidating the immunosuppressive mechanism and developing effective immunotherapeutic strategies are necessary. Here, we found that the Th1% and IFN-γ level were downregulated in bone marrow of AML and NLRP3-activated BMDCs promoted CD4⁺ T cell differentiation into Th1 cells via IL-1β secretion. However, IFN-γ-producing Th1 cells were not induced by NLRP3-activated BMDCs in the presence of the NLRP3 inflammasome inhibitor MCC950 or anti-IL-1β antibody in vitro unless exogenous IL-1β was replenished. This inhibitory effect on Th1 differentiation was also observed in Nlrp3^-/- mice or anti-IL-1β antibody-treated mice. Notably, elevated Th1 cell levels promoted apoptosis and inhibited proliferation in leukemia cells via IFN-γ secretion in vitro and in vivo. Thus, NLRP3-activated BMDCs promote the proliferation of IFN-γ-producing Th1 cells with antileukemic effects and may provide insight into the basis for leukemia immunotherapy in patients with AML.

Clinical effects of administering leukemia-specific donor T cells to patients with AML/MDS after allogeneic transplant

Relapse after allogeneic hematopoietic stem cell transplantation (HCT) is the leading cause of death in patients with acute myeloid leukemia (AML) or myelodysplastic syndrome (MDS). Infusion of unselected donor lymphocytes (DLIs) enhances the graft-versus-leukemia (GVL) effect. However, because the infused lymphocytes are not selected for leukemia specificity, the GVL effect is often accompanied by life-threatening graft-versus-host disease (GVHD), related to the concurrent transfer of alloreactive lymphocytes. Thus, to minimize GVHD and maximize GVL, we selectively activated and expanded stem cell donor-derived T cells reactive to multiple antigens expressed by AML/MDS cells (PRAME, WT1, Survivin, and NY-ESO-1). Products that demonstrated leukemia antigen specificity were generated from 29 HCT donors. In contrast to DLIs, leukemia-specific T cells (mLSTs) selectively recognized and killed leukemia antigen-pulsed cells, with no activity against recipient's normal cells in vitro. We administered escalating doses of mLSTs (0.5 to 10 × 107 cells per square meter) to 25 trial enrollees, 17 with high risk of relapse and 8 with relapsed disease. Infusions were well tolerated with no grade >2 acute or extensive chronic GVHD seen. We observed antileukemia effects in vivo that translated into not-yet-reached median leukemia-free and overall survival at 1.9 years of follow-up and objective responses in the active disease cohort (1 complete response and 1 partial response). In summary, mLSTs are safe and promising for the prevention and treatment of AML/MDS after HCT. This trial is registered at www.clinicaltrials.com as #NCT02494167.

Leukemia vaccine overcomes limitations of checkpoint blockade by evoking clonal T cell responses in a murine acute myeloid leukemia model

We have developed a personalized vaccine whereby patient derived leukemia cells are fused to autologous dendritic cells, evoking a polyclonal T cell response against shared and neo-antigens. We postulated that the dendritic cell (DC)/AML fusion vaccine would demonstrate synergy with checkpoint blockade by expanding tumor antigen specific lymphocytes that would provide a critical substrate for checkpoint blockade mediated activation. Using an immunocompetent murine leukemia model, we examined the immunologic response and therapeutic efficacy of vaccination in conjunction with checkpoint blockade with respect to leukemia engraftment, disease burden, survival and the induction of tumor specific immunity. Mice treated with checkpoint blockade alone had rapid leukemia progression and demonstrated only a modest extension of survival. Vaccination with DC/AML fusions resulted in the expansion of tumor specific lymphocytes and disease eradication in a subset of animals, while the combination of vaccination and checkpoint blockade induced a fully protective tumor specific immune response in all treated animals. Vaccination followed by checkpoint blockade resulted in upregulation of genes regulating activation and proliferation in memory and effector T cells. Long term survivors exhibited increased T cell clonal diversity and were resistant to subsequent tumor challenge. The combined DC/AML fusion vaccine and checkpoint blockade treatment offers unique synergy inducing the durable activation of leukemia specific immunity, protection from lethal tumor challenge and the selective expansion of tumor reactive clones.

CAR-T Cell Therapy for Acute Myeloid Leukemia: Preclinical Rationale, Current Clinical Progress, and Barriers to Success

Chimeric antigen receptor (CAR)-T cell therapy has shown impressive results in chemorefractory B cell malignancies, raising the possibilities of using this immunotherapeutic modality for other devastating hematologic malignancies, such as acute myeloid leukemia (AML). AML is an aggressive hematologic malignancy which, like B cell malignancies, poses several challenges for clinical translation of successful immunotherapy. The antigenic heterogeneity of AML results in a list of potential targets that CAR-T cells could be directed towards, each with advantages and disadvantages. In this review, we provide an up-to-date report of outcomes and adverse effects from published and presented clinical trials of CAR-T cell therapy for AML and provide the preclinical rationale underlying these studies and antigen selection. Comparison across trials is difficult, yet themes emerge with respect to appropriate antigen selection and association of adverse effects with outcomes. We highlight currently active clinical trials and the potential improvements and caveats with these novel approaches. Key hurdles to the successful introduction of CAR-T cell therapy for the treatment of AML include the effect of antigenic heterogeneity and trade-offs between therapy specificity and sensitivity; on-target off-tumor toxicities; the AML tumor microenvironment; and practical considerations for future trials that should be addressed to enable successful CAR-T cell therapy for AML.

Mechanisms of Action of Hypomethylating Agents: Endogenous Retroelements at the Epicenter

Abnormal DNA methylation patterns are thought to drive the pathobiology of high-risk myelodysplastic syndromes (HR-MDS) and acute myeloid leukemia (AML). Sixteen years after their initial approval, the hypomethylating agents (HMAs), 5-azacytidine (AZA) and 5-aza-2′-deoxycytidine, remain the mainstay of treatment for HR-MDS and AML. However, a connection of the hypomethylating or additional effects of HMAs with clinical responses remains yet to be shown, and the mode of action of HMAs remains obscure. Given the relatively short-lived responses and the inevitable development of resistance in HMAs, a thorough understanding of the antineoplastic mechanisms employed by HMAs holds critical importance. Recent data in cancer cell lines demonstrate that reactivation of endogenous retroelements (EREs) and induction of a cell-intrinsic antiviral response triggered by RNA neotranscripts may underlie the antitumor activity of HMAs. However, data on primary CD34⁺ cells derived from patients with HR-MDS failed to confirm a link between HMA-mediated ERE modulation and clinical response. Though difficult to reconcile the apparent discrepancy, it is possible that HMAs mediate their effects in more advanced levels of differentiation where cells become responsive to interferon, whereas, inter-individual variations in the process of RNA editing and, in particular, in the ADAR1/OAS/RNase L pathway may also confound the associations of clinical response with the induction of viral mimicry. Further ex vivo studies along with clinical correlations in well-annotated patient cohorts are warranted to decipher the role of ERE derepression in the antineoplastic mechanisms of HMAs.

Development of a poor-prognostic-mutations derived immune prognostic model for acute myeloid leukemia

Leukemia cell-intrinsic somatic mutations and cytogenetic abnormalities have been used to define risk categories in acute myeloid leukemia (AML). In addition, since the immune microenvironment might influence prognosis and somatic mutations have been demonstrated to modulate the immune microenvironment in AML, there is need for developing and evaluating an immune prognostic model (IPM) derived from mutations associated with poor prognosis. Based on AML cases with intermediate and adverse-cytogenetic risk in the Cancer Genome Atlas (TCGA) database, 64 immune-related differentially expressed genes (DEGs) among patients with RUNX1, TP53, or ASXL1 mutations and patients without these mutations were identified. After Cox proportional hazards analysis, an IPM composed of PYCARD and PEAR1 genes was constructed. IPM defined high-risk (IPM-HR) independently predicted lower 2-year overall survival (OS) rates in both patients with intermediate and adverse-cytogenetic risks and non-M3 patients in the TCGA AML cohort. The poor prognostic impact of IPM-HR on OS was further validated by GSE71014, 37642, and 10358 downloaded from the Gene Expression Omnibus (GEO) database. Furthermore, IPM-HR was remarkably associated with higher proportions of CD8+ T cells and regulatory T cells (Tregs), lower proportions of eosinophils, and higher expression of the checkpoint molecules CTLA-4, PD-1, and LAG3 in the TCGA non-M3 AML cohort. In summary, we developed and validated an IPM derived from mutations related with poor prognosis in AML, which would provide new biomarkers for patient stratification and personalized immunotherapy.

Hypomethylating Agents and Immunotherapy: Therapeutic Synergism in Acute Myeloid Leukemia and Myelodysplastic Syndromes

Decitabine and guadecitabine are hypomethylating agents (HMAs) that exert inhibitory effects against cancer cells. This includes stimulation of anti-tumor immunity in acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS) patients. Treatment of AML and MDS patients with the HMAs confers upregulation of cancer/testis antigens (CTAs) expression including the highly immunogenic CTA NY-ESO-1. This leads to activation of CD4⁺ and CD8⁺ T cells for elimination of cancer cells, and it establishes the feasibility to combine cancer vaccine with HMAs to enhance vaccine immunogenicity. Moreover, decitabine and guadecitabine induce the expression of immune checkpoint molecules in AML cells. In this review, the accumulating knowledge on the immunopotentiating properties of decitabine and guadecitabine in AML and MDS patients are presented and discussed. In summary, combination of decitabine or guadecitabine with NY-ESO-1 vaccine enhances vaccine immunogenicity in AML patients. T cells from AML patients stimulated with dendritic cell (DC)/AML fusion vaccine and guadecitabine display increased capacity to lyse AML cells. Moreover, decitabine enhances NK cell-mediated cytotoxicity or CD123-specific chimeric antigen receptor-engineered T cells antileukemic activities against AML. Furthermore, combination of either HMAs with immune checkpoint blockade (ICB) therapy may circumvent their resistance. Finally, clinical trials of either HMAs combined with cancer vaccines, NK cell infusion or ICB therapy in relapsed/refractory AML and high-risk MDS patients are currently underway, highlighting the promising efficacy of HMAs and immunotherapy synergy against these malignancies.

Durable Remission of Chemotherapy-Refractory Myeloid Sarcoma by Azacitidine

Myeloid sarcoma is a rare disease entity of extramedullary myeloid neoplasm that can occur both as an initial isolated myeloid sarcoma without leukemic cell invasion in the peripheral blood and bone marrow, and as the secondary lesion of acute and chronic myeloid leukemias, myelodysplastic syndrome and chronic myeloproliferative neoplasms. Due to its rarity and its frequent emergence as the recurrent lesion after intensive systemic therapy, including allogeneic hematopoietic stem cell transplantation, the standard treatment has not been established for myeloid sarcoma. In this report, we presented an 84-year-old female patient with isolated myeloid sarcoma which progressed to myelodysplastic syndrome and systemic myeloid sarcoma despite various types of conventional anti-leukemic chemotherapies. However, the patient got a durable partial response by the monotherapy of azacitidine, a hypomethylating agent. She received thirteen courses of azacitidine therapy without progression. We discuss the possibility that hypomethylating agents are the novel effective and feasible therapeutic options for myeloid sarcoma, even in cases refractory to or relapsed after intensive systemic treatment. We also discuss the possible future development of hypomethylating agent-containing combinatory therapeutic strategy for myeloid sarcoma, given its direct anti-leukemic effect and immunomodulatory effect.

Casting a wider protective net: Anti-infective vaccine strategies for patients with hematologic malignancy and blood and marrow transplantation

Patients who have hematologic malignancies are at high risk for infections but vaccinations may be effective prophylaxis. The increased infection risk derives from immune defects secondary to malignancy, the classic example being CLL, and chemotherapies and immunotherapy used to treat the malignancies. Therapy of hematologic malignancies is being revolutionized by introduction of novel targeted agents and immunomodulatory medications, improving the survival of patients. At the same time those agents uniquely change the infection risk and response to immunizations. This review will summarize current vaccine recommendations for patients with hematologic malignancies including patients who undergo hematopoietic cell transplant.

Case Report: Low-Dose Decitabine Plus Anti-PD-1 Inhibitor Camrelizumab for Previously Treated Advanced Metastatic Non-Small Cell Lung Cancer

Background: Although the programmed death 1 (PD-1)/programmed death-ligand 1 (PD-L1) inhibitors have markedly changed the strategies of cancer treatment, most patients with advanced non-small cell lung cancer (NSCLC) do not respond to PD-1/PD-L1 monotherapy. Epigenetic drugs have been hypothesized to possess the potential to sensitize PD-1/PD-L1 inhibitors.

Case Presentation: Three patients with advanced metastatic NSCLC failed to respond to first-line systemic therapy and had a low tumor mutation burden, low tumor neoantigen burden, low microsatellite instability, and HLA loss of heterozygosity according to their target lesion biopsies, all of which were considered unfavorable factors for PD-1/PD-L1 blockage. However, all three patients responded to low-dose decitabine, an epigenetic drug, in combination with camrelizumab (anti-PD-1 antibody), with only controllable adverse events, indicating that low-dose decitabine can sensitize PD-1/PD-L1 inhibitors.

Summary: We report a novel therapy with low-dose decitabine plus camrelizumab for advanced NSCLC on the basis of successful treatment of three patients, emphasizing the potential of epigenetic drugs to regulate PD-1/PD-L1 inhibitors in advanced NSCLC.

Combined cytotoxic chemotherapy and immunotherapy of cancer: modern times

Monoclonal antibodies targeting programmed cell death 1/programmed cell death ligand 1 (PD-1/PD-L1) immune checkpoints have improved the treatments of cancers. However, not all patients equally benefit from immunotherapy. The use of cytotoxic drugs is practically inevitable to treat advanced cancers and metastases. The repertoire of cytotoxics includes 80 products that principally target nucleic acids or the microtubule network in rapidly proliferating tumor cells. Paradoxically, many of these compounds tend to become essential to promote the activity of immunotherapy and to offer a sustained therapeutic effect. We have analyzed each cytotoxic drug with respect to effect on expression and function of PD-(L)1. The major cytotoxic drugs—carboplatin, cisplatin, cytarabine, dacarbazine, docetaxel, doxorubicin, ecteinascidin, etoposide, fluorouracil, gemcitabine, irinotecan, oxaliplatin, paclitaxel and pemetrexed—all have the capacity to upregulate PD-L1 expression on cancer cells (via the generation of danger signals) and to promote antitumor immunogenicity, via activation of cytotoxic T lymphocytes, maturation of antigen-presenting cells, depletion of immunosuppressive regulatory T cells and/or expansion of myeloid-derived suppressor cells. The use of ‘immunocompatible’ cytotoxic drugs combined with anti-PD-(L)1 antibodies is a modern approach, not only for increasing the direct killing of cancer cells, but also as a strategy to minimize the activation of immunosuppressive and cancer cell prosurvival program responses.

The Interplay Between the Genetic and Immune Landscapes of AML: Mechanisms and Implications for Risk Stratification and Therapy

AML holds a unique place in the history of immunotherapy by virtue of being among the first malignancies in which durable remissions were achieved with "adoptive immunotherapy," now known as allogeneic stem cell transplantation. The successful deployment of unselected adoptive cell therapy established AML as a disease responsive to immunomodulation. Classification systems for AML have been refined and expanded over the years in an effort to capture the variability of this heterogeneous disease and risk-stratify patients. Current systems increasingly incorporate information about cytogenetic alterations and genetic mutations. The advent of next generation sequencing technology has enabled the comprehensive identification of recurrent genetic mutations, many with predictive power. Recurrent genetic mutations found in AML have been intensely studied from a cell intrinsic perspective leading to the genesis of multiple, recently approved targeted therapies including IDH1/2-mutant inhibitors and FLT3-ITD/-TKD inhibitors. However, there is a paucity of data on the effects of these targeted agents on the leukemia microenvironment, including the immune system. Recently, the phenomenal success of checkpoint inhibitors and CAR-T cells has re-ignited interest in understanding the mechanisms leading to immune dysregulation and suppression in leukemia, with the objective of harnessing the power of the immune system via novel immunotherapeutics. A paradigm has emerged that places crosstalk with the immune system at the crux of any effective therapy. Ongoing research will reveal how AML genetics inform the composition of the immune microenvironment paving the way for personalized immunotherapy.

Identification of prognostic genes in the acute myeloid leukemia immune microenvironment based on TCGA data analysis

Acute myeloid leukemia (AML) is a common and lethal hematopoietic malignancy that is highly dependent on the bone marrow (BM) microenvironment. Infiltrating immune and stromal cells are important components of the BM microenvironment and significantly influence the progression of AML. This study aimed to elucidate the value of immune/stromal cell-associated genes for AML prognosis by integrated bioinformatics analysis. We obtained expression profiles from The Cancer Genome Atlas (TCGA) database and used the ESTIMATE algorithm to calculate immune scores and stromal scores; we then identified differentially expressed genes (DEGs) based on these scores. Overall survival analysis was applied to reveal common DEGs of prognostic value. Subsequently, we conducted a functional enrichment analysis, generated a protein-protein interaction (PPI) network and performed an interrelation analysis of immune system processes, showing that these genes are mainly associated with the immune/inflammatory response. Finally, eight genes (CD163, CYP27A1, KCNA5, PPM1J, FOLR1, IL1R2, MYOF, VSIG2) were verified to be significantly associated with AML prognosis in the Gene Expression Omnibus (GEO) database. In summary, we identified key microenvironment-related genes that affect the outcomes of AML patients and might serve as therapeutic targets.

Dendritic Cell-Based Immunotherapy of Acute Myeloid Leukemia

Acute myeloid leukemia (AML) is a type of blood cancer characterized by the uncontrolled clonal proliferation of myeloid hematopoietic progenitor cells in the bone marrow. The outcome of AML is poor, with five-year overall survival rates of less than 10% for the predominant group of patients older than 65 years. One of the main reasons for this poor outcome is that the majority of AML patients will relapse, even after they have attained complete remission by chemotherapy. Chemotherapy, supplemented with allogeneic hematopoietic stem cell transplantation in patients at high risk of relapse, is still the cornerstone of current AML treatment. Both therapies are, however, associated with significant morbidity and mortality. These observations illustrate the need for more effective and less toxic treatment options, especially in elderly AML and have fostered the development of novel immune-based strategies to treat AML. One of these strategies involves the use of a special type of immune cells, the dendritic cells (DCs). As central orchestrators of the immune system, DCs are key to the induction of anti-leukemia immunity. In this review, we provide an update of the clinical experience that has been obtained so far with this form of immunotherapy in patients with AML.