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Acute myeloid leukemias (AMLs) comprise a group of genetically heterogeneous hematological malignancies that result in the abnormal growth of leukemic cells and halt the maturation process of normal hematopoietic stem cells. Despite using molecular and cytogenetic risk classification to guide treatment decisions, most AML patients survive for less than five years. A deeper comprehension of the disease’s biology and the use of new, targeted therapy approaches could potentially increase cure rates. RAS oncogene mutations are common in AML patients, being observed in about 15–20% of AML cases. Despite extensive efforts to find targeted therapy for RAS-mutated AMLs, no effective and tolerable RAS inhibitor has received approval for use against AMLs. The frequency of RAS mutations increases in the context of AMLs’ chemoresistance; thus, novel anti-RAS strategies to overcome drug resistance and improve patients’ therapy responses and overall survival are the need of the hour. In this article, we aim to update the current knowledge on the role of RAS mutations and anti-RAS strategies in AML treatments.

Acute myeloid leukemia (AML), an aggressive malignancy of hematopoietic stem cells, is characterized by the blockade of cell differentiation, uncontrolled proliferation, and cell expansion that impairs healthy hematopoiesis and results in pancytopenia and susceptibility to infections. Several genetic and chromosomal aberrations play a role in AML and influence patient outcomes. TP53 is a key tumor suppressor gene involved in a variety of cell features, such as cell-cycle regulation, genome stability, proliferation, differentiation, stem-cell homeostasis, apoptosis, metabolism, senescence, and the repair of DNA damage in response to cellular stress. In AML, TP53 alterations occur in 5%–12% of de novo AML cases. These mutations form an important molecular subgroup, and patients with these mutations have the worst prognosis and shortest overall survival among patients with AML, even when treated with aggressive chemotherapy and allogeneic stem cell transplant. The frequency of TP53-mutations increases in relapsed and recurrent AML and is associated with chemoresistance. Progress in AML genetics and biology has brought the novel therapies, however, the clinical benefit of these agents for patients whose disease is driven by TP53 mutations remains largely unexplored. This review focuses on the molecular characteristics of TP53-mutated disease; the impact of TP53 on selected hallmarks of leukemia, particularly metabolic rewiring and immune evasion, the clinical importance of TP53 mutations; and the current progress in the development of preclinical and clinical therapeutic strategies to treat TP53-mutated disease.

Abstract Interferon gamma (IFNγ) is a critical cytokine known for its diverse roles in immune regulation, inflammation, and tumor surveillance. However, while IFNγ levels were elevated in sera of most newly diagnosed acute myeloid leukemia (AML) patients, its complex interplay in AML remains insufficiently understood. We aim to characterize these complex interactions through comprehensive bulk and single-cell approaches in bone marrow of newly diagnosed AML patients. We identify monocytic AML as having a unique microenvironment characterized by IFNγ producing T and NK cells, high IFNγ signaling, and immunosuppressive features. IFNγ signaling score strongly correlates with venetoclax resistance in primary AML patient cells. Additionally, IFNγ treatment of primary AML patient cells increased venetoclax resistance. Lastly, a parsimonious 47-gene IFNγ score demonstrates robust prognostic value. In summary, our findings suggest that inhibiting IFNγ is a potential treatment strategy to overcoming venetoclax resistance and immune evasion in AML patients.

Abstract DNA damage resistance is a major barrier to effective DNA-damaging therapy in multiple myeloma (MM). To discover mechanisms through which MM cells overcome DNA damage, we investigate how MM cells become resistant to antisense oligonucleotide (ASO) therapy targeting Interleukin enhancer binding factor 2 (ILF2), a DNA damage regulator that is overexpressed in 70% of MM patients whose disease has progressed after standard therapies have failed. Here, we show that MM cells undergo adaptive metabolic rewiring to restore energy balance and promote survival in response to DNA damage activation. Using a CRISPR/Cas9 screening strategy, we identify the mitochondrial DNA repair protein DNA2, whose loss of function suppresses MM cells’ ability to overcome ILF2 ASO−induced DNA damage, as being essential to counteracting oxidative DNA damage. Our study reveals a mechanism of vulnerability of MM cells that have an increased demand for mitochondrial metabolism upon DNA damage activation.

Macrophages represent an important component of the innate immune system. Under physiological conditions, macrophages, which are essential phagocytes, maintain a proinflammatory response and repair damaged tissue. However, these processes are often impaired upon tumorigenesis, in which tumor-associated macrophages (TAMs) protect and support the growth, proliferation, and invasion of tumor cells and promote suppression of antitumor immunity. TAM abundance is closely associated with poor outcome of cancer, with impediment of chemotherapy effectiveness and ultimately a dismal therapy response and inferior overall survival. Thus, cross-talk between cancer cells and TAMs is an important target for immune checkpoint therapies and metabolic interventions, spurring interest in it as a therapeutic vulnerability for both hematological cancers and solid tumors. Furthermore, targeting of this cross-talk has emerged as a promising strategy for cancer treatment with the antibody against CD47 protein, a critical macrophage checkpoint recognized as the “don’t eat me” signal, as well as other metabolism-focused strategies. Therapies targeting CD47 constitute an important milestone in the advancement of anticancer research and have had promising effects on not only phagocytosis activation but also innate and adaptive immune system activation, effectively counteracting tumor cells’ evasion of therapy as shown in the context of myeloid cancers. Targeting of CD47 signaling is only one of several possibilities to reverse the immunosuppressive and tumor-protective tumor environment with the aim of enhancing the antitumor response. Several preclinical studies identified signaling pathways that regulate the recruitment, polarization, or metabolism of TAMs. In this review, we summarize the current understanding of the role of macrophages in cancer progression and the mechanisms by which they communicate with tumor cells. Additionally, we dissect various therapeutic strategies developed to target macrophage–tumor cell cross-talk, including modulation of macrophage polarization, blockade of signaling pathways, and disruption of physical interactions between leukemia cells and macrophages. Finally, we highlight the challenges associated with tumor hypoxia and acidosis as barriers to effective cancer therapy and discuss opportunities for future research in this field.

Immunotherapy, in the form of hematopoietic stem cell transplantation (HSCT), has been part of the standard of care in the treatment of acute leukemia for over 40 years. Trials evaluating novel immunotherapeutic approaches, such as targeting the programmed death-1 (PD-1) pathway, have unfortunately not yielded comparable results to those seen in solid tumors. Major histocompatibility complex (MHC) proteins are cell surface proteins essential for the adaptive immune system to recognize self versus non-self. MHC typing is used to determine donor compatibility when evaluating patients for HSCT. Recently, loss of MHC class II (MHC II) was shown to be a mechanism of immune escape in patients with acute myeloid leukemia after HSCT. Here we report that treatment with the tyrosine kinase inhibitor, dasatinib, and an anti-PD-1 antibody in preclinical models of Philadelphia chromosome positive B-cell acute lymphoblastic leukemia is highly active. The dasatinib and anti-PD-1 combination reduces tumor burden, is efficacious, and extends survival. Mechanistically, we found that treatment with dasatinib significantly increased MHC II expression on the surface of antigen-presenting cells (APC) in a tumor microenvironment-independent fashion and caused influx of APC cells into the leukemic bone marrow. Finally, the induction of MHC II may potentiate immune memory by impairing leukemic engraftment in mice previously cured with dasatinib, after re-inoculation of leukemia cells. In summary, our data suggests that anti-PD-1 therapy may enhance the killing ability of dasatinib via dasatinib driven APC growth and expansion and upregulation of MHC II expression, leading to antileukemic immune rewiring.

Introduction and purpose Art-therapy is a therapeutic method which uses art as a tool to achieve benefits in physical and mental health. This kind of psychotherapy uses artistic media as a basic form of communication. As an additional form of treatment, combined with medication, it helps not only to explore a patient’s difficulties and problems but also to overcome them. Art-therapy is playing an increasing role in the context of health in individuals struggling with different diseases, especially with the mental ones. This is a growing field of research and the aim of this brief review is to provide an update on the positive effects of art-therapy and to list health problems in which it would be significant to use this kind of therapy. Materials and methods A search was conducted using PubMed and GoogleScholar data bases. Articles were searched in English using the following key words: “art therapy”, “psychodrama”, “dance movement therapy”, “music therapy”, “creative art therapy”. Description of the state of knowledge Art-therapy has a wide range of benefits in chronically ill patients. Most common are the awareness of the emotions and behaviors and helping to deal with them, helping to deal with the process of treatment. The literature also draws attention to other results such as increasing self- esteem and improving the quality of life. Summary Art-therapy is associated with health benefits in people struggling with different health problems. Art-therapy has great potential to participate in future basic and adjunctive therapy but further research is needed in this area.

Introduction and purpose Traditional Chinese herbal medicine is an integral component of a comprehensive healing system known as Traditional Chinese Medicine (TCM). Within TCM, herbs are utilized to rebalance the energy forces of Yin and Yang, which flow through imperceptible channels within the body with the aim of restoring energy equilibrium. It is important to acknowledge that herbs have the potential to exert significant effects on the body comparable to pharmaceutical drugs, and therefore, should be approached with equal caution and respect The aim of the study was to present the current state of knowledge about the potential use of Chinese herbs in the treatment of certain dermatological and endocrine diseases. State of the knowledge Chinese medicine has found application in various diseases and health conditions, both physical and mental. In the studies delving into dermatological diseases, Chinese medicine therapy resulted in a reduction in chronic urticaria activity and psoriasis area severity index. In addition, Chinese herbal medicine (CHM) effectively improved the response rate and reduced the maximum nodule diameter of benign thyroid nodules. Furthermore it was reported that certain Chinese herbs improve the functioning of mitochondria in β-cells contributing to better management of patients with diabetes mellitus. Conclusion Chinese medicine seems to be a valuable supplement to conventional medicine in the treatment of some chronic diseases. Simultaneously, our focus should be on the development of a new wave of pharmaceutical products that guarantee high efficacy and low toxicity conforming to international standards. It is imperative to enhance research in Chinese medicine and advance engineering technologies to ensure the superior quality of TCM preparations.

Introduction and purpose: Kombucha is a fermented beverage, usually made by fermenting sugared black or green tea with the symbiotic culture of bacteria and yeast (SCOBY). Kombucha has gained increasing popularity in recent years, mainly due to the fact that it has been associated with some health effects. The aim of the study is to review the articles available in the PubMed database in order to learn about the health benefits of Kombucha consumption. State of knowledge: Kombucha is a source of phenolic compounds, vitamins and minerals, amino acids, enzymes, proteins and other compounds which influence biological activity. Scientific research on Kombucha has shown that it exhibits antioxidant, antibacterial, anti-inflammatory, anti-cancerogenic and antidiabetic properties. It also has a good influence on the digestive system. Kombucha consumption helps to lower cholesterol level, stimulates liver detoxification processes and also supports the proper functioning of the immune system. These properties depend on the various factors such as used products, concentration of bacteria and yeast, duration of fermentation or temperature. Summary: Kombucha tea is known as a nutraceutical. It could be used as a dietary supplement. Most of the trials have been conducted on rats or mice. Kombucha has only been involved or tested in a few human trials. It is important to spread awareness among the population about this product and its impact on people’s health, conduct more research and standardise the production methods of this beverage.

Introduction and purpose: For all skin types, micro-needle radiofrequency (FMR) can be a safe and effective aesthetic medicine procedure for the treatment of various dermatological and aesthetic conditions. The aim of the study is to present the mechanism of action and assess safety, treatment efficacy, and possible side effects on the basis of a review of the scientific literature. Description of the state of knowledge: FMR uses micro-needles to penetrate the skin to a depth of up to 4.5 mm and deliver radiofrequency current in a fractional manner, producing the controlled fractions of micro-injuries in the dermis, inducing neocollagenesis, neoelastinogenesis, and angiogenesis. FMR has a wide range of positive effects such as skin rejuvenation, skin tightening, facial and body scar remodeling, and hair growth through transdermal collagen induction. Summary: Increasingly, patients are looking for minimally invasive methods of skin tightening and fat remodeling. In response, Aesthetic Medicine has proposed a combination of two techniques, micro-needling and radiofrequency. As more and more studies are showing the effectiveness and efficiency of this procedure, also emphasizing its safety, minimal risk of serious side effects, and ease of use, micro-needle radiofrequency is being proposed as an attractive answer to people's desires for a less invasive method of skin rejuvenation. However, further research in this area is needed to optimize the parameters of the treatment to achieve the best results.

Introduction and purpose: Hidradenitis suppurativa (HS) also known as acne inversa is a chronic, inflammatory dermatosis with predilection to apocrine gland-rich regions. It is a multifactorial disease in which genetic and environmental factors play a key role. In this paper, we provide an overview of the current knowledge in most commonly used and emerging treatment options of HS. A brief description of the state of knowledge: The primary defect in HS pathophysiology involves follicular hyperkeratosis with occlusion of the pilosebaceous apparatus, followed by follicular rupture and immune responses. It typically develops after puberty with deep-seated painful nodules, abscesses, sinus tracts and scars. Due to the permanently painful, odorous lesions, hidradenitis suppurativa is one of the most distressing dermatological diseases with a substantial impact on patients’ quality of life. Inflammation in patients with HS is not limited to the skin but is systemic. Patients with HS frequently have significant comorbidities like metabolic syndrome, type 2 diabetes mellitus, spondyloarthropathy, inflammatory bowel disease and depression. Treatment is challenging and consists of pharmacological and surgical techniques, which must often be combined for best results. Materials and methods: A search was conducted using PubMed and GoogleScholar data bases. Articles were searched in English using the following key words: “hidradenitis suppurativa”, “acne invera”, “treatement”, “management”, “biological treatement”. Summary: Therapeutic options have rapidly evolved in the last decade and include the use of topical therapies, systemic antibiotics and a wide range of immunosuppressive medications such as anti-TNF-α biologics, but the number of therapies approved for HS is limited.

Introduction and purpose: Microneedle mesotherapy is a non-surgical method consisting in controlled micropuncture of the skin with very thin needles, associated with the insertion of active substances into it. It is used in many fields of medicine, diseases, as well as cosmetic defects associated with the symptoms of skin aging. The aim of this review is to summarize the side effects described in the literature that may associated microneedle mesotherapy. The review was based on the available data collected in the PubMed database searched using the keywords "mesotherapy", "adverse effects", "side effects". Description of the state of knowledge: Complications of mesotherapy can be divided into infectious and non-infectious as well as local and systemic. The most common and best known are bruises and swelling caused by local inflammation caused by certain substances. More serious complications include anaphylaxis, skin necrosis, granulomas, cellulitis, and infectious complications. Summary: Mesotherapy is a commonly performed procedure not only by doctors, but also by non-medical people. Both patients and operators tend to underestimate the potential side effects of this method. We hope that raising awareness and paying attention to the errors made will contribute to reducing the complications associated with this procedure, as well as to its standardization.

Introduction and purpose: Varicose veins of the lower limbs are quite common and common disease. Their presence may be associated with the occurrence of a number of symptoms that negatively affect the quality and comfort of life, such as swelling, leg pain and cosmetic defect.The aim of the study is to review the available literature and articles available in the PubMed database in order to learn about the pathophysiology of varicose veins, methods of diagnosis and the most popular methods of their treatment. State of the knowledge: Varicose veins are described as fusiform dilatation of superficial veins with accompanying elongation and characteristic twisting. The main cause of their formation is insufficiency of the venous valve apparatus. Genetic and individual factors such as sex, age, and excessive body weight also have an impact. The diagnosis is based primarily on the physical examination of the patient and the Doppler ultrasound examination of the veins. Management options for varicose veins range from conservative management including pharmacotherapy to invasive and surgical methods, each of which has both advantages and disadvantages. Summary: Making a diagnosis of varicose veins usually does not cause many difficulties. There is no one-size-fits-all treatment method. When choosing it, many aspects should be taken into account, such as the patient's preferences, severity of disease symptoms, and the patient's general condition.

Introduction and purpose Breast cancer (BC) management includes local therapies surgery, radiotherapy and systemic – hormonotherapy, chemotherapy, targeted and immunotherapy. However, some adverse events of these treatment strategies limit their wide administration in BC therapy. The aim of the study was to present adverse effects in the management of BC, prevention and treatment of them. State of the knowledge Surgery of the breast leads to lymphedema, pain, and anatomical changes. The most characteristic adverse event of radiotherapy is radiation dermatitis which is more probable among obese, older patients, females, and smokers. Other side effects are pneumonia, cardiac and pulmonary injury. Chemotherapeutics lead to complications such as anthracyclines-induced cardiotoxicity. As a consequence of endocrine therapy, patients are affected by vasomotor, musculoskeletal, and vulvovaginal symptoms. Immune checkpoint inhibitors may cause immune-related adverse events (irAEs), which are usually mild. When severe irAEs occur, immunosuppressive drugs are used. Depending on stage, toxicities of the therapies can lead to interrupting the treatment of BC. Moreover, drug resistance is an important therapeutic obstacle in BC treatment. Conclusion The application of a diversity of drugs in the treatment of breast cancer is associated with adverse effects which limit its efficacy. It is vital to develop novel, targeted therapeutic methods to optimize outcomes of patients. Given the adverse effects of breast cancer therapies and drug resistance, it is vital to develop novel, targeted therapeutic methods.

Notch1 is frequently activated promoting T-cell acute lymphoblastic leukaemia (T-ALL). Here, the authors show that Notch1 induces oxidative phosphorylation dependency in T-ALL and synergism when inhibiting both mitochondrial complex I and glutaminolysis in preclinical murine and human xenograft models.

IntroductionChronic lymphocytic leukemia (CLL) cells are metabolically flexible and adapt to modern anticancer treatments. Bruton tyrosine kinase (BTK) and B-cell lymphoma-2 (BCL-2) inhibitors have been widely used to treat CLL, but CLL cells become resistant to these treatments over time. CB-839 is a small-molecule glutaminase-1 (GLS-1) inhibitor that impairs glutamine use, disrupts downstream energy metabolism, and impedes the elimination of reactive oxygen species.MethodsTo investigate the in vitro effects of CB-839 on CLL cells, we tested CB-839 alone and in combination with ibrutinib, venetoclax, or AZD-5991 on the HG-3 and MEC-1 CLL cell lines and on primary CLL lymphocytes.ResultsWe found that CB-839 caused dose-dependent decreases in GLS-1 activity and glutathione synthesis. CB-839–treated cells also showed increased mitochondrial superoxide metabolism and impaired energy metabolism, which were reflected in decreases in the oxygen consumption rate and depletion of the adenosine triphosphate pool and led to the inhibition of cell proliferation. In the cell lines, CB-839 combined with venetoclax or AZD-5991, but not with ibrutinib, demonstrated synergism with an increased apoptosis rate and cell proliferation inhibition. In the primary lymphocytes, no significant effects of CB-839 alone or in combination with venetoclax, ibrutinib, or AZD-5991 were observed.DiscussionOur findings suggest that CB-839 has limited efficacy in CLL treatment and shows limited synergy in combination with widely used CLL drugs.

Introduction and purpose Depression is the most common mental disorder, but the exact mechanisms underlying the pathophysiology of depression remain unknown. Abundant research evidence suggests that changes in the gut microbiota play a key role in the pathophysiology of depression through the brain-gut-microbiota axis. The aim of this study was to present the current state of knowledge on the role of gut microbiota in pathogenesis and treatment of depression and discuss its potential as a therapeutic target for depression A brief description of the state of knowledge The digestive tract and the processes which are set in it as well as the inhabitting microorganisms have a significant impact on our mental health and mood. The scientific research repeatidly confirm a strict relationship between the digestive and nervous systems. A microbiome-based approach is becoming increasingly prevalent in the understanding and treatment of neuropsychiatric disorders, especially depression. Antidepressants which are today the first-line therapy in the treatment of this disease are based inter alia on the antimicrobial and immunomodulatory mechanism of action. Conclusion Immune cells which are settled in the intestines affect not only our physical health but also the mental one. Due to the relationship between depression and the gut microbiota, we have many treatment options that involve direct modification of the composition of the microbiome which include prebiotics, probiotics (psychobiotics) and faecal microbiome transplantation.

Introduction and purpose: Ashwagandha (fam. Solanaceae) also known as Withania somnifera, is an herb commonly used in traditional Ayurvedic medicine. It is sometimes called Indian ginseng or winter cherry and it is used for its extensive health benefits for millennia as a Rasayana. Ashwagadha supplementation is playing an increasing role not only as an adaptogen, but is beneficial in the context of health in individuals struggling with obesity. This is a growing field of research and the aim of this brief review is to provide an update on the positive effects of Ashwagandha supplementation on the health of those dealing with obesity. Description of the state of knowledge: Ashwagandha has a wide range of positive effects, most common are sedative, anti-stress, immunomodulatory and anti-cancer effects. The literature also draws attention to other results such as binding insulin sensitivity, increasing endurance, effects on adipogenesis and lipogenesis. Ashwagandha lowers blood cortisol levels, inhibits fat accumulation and the expression of genes involved into excessive fat tissue accumulation. Summary: Regular intake of Ashwagandha is associated with health benefits in people struggling with obesity. As an adaptogen with adipogenic potential, Ashwagandha has great potential to participate in future adjunctive obesity therapy and the prevention of other similar and obesity-related diseases, but further research is needed in this area.

Abstract Despite high initial response rates, acute myeloid leukemia (AML) treated with the BCL-2–selective inhibitor venetoclax (VEN) alone or in combinations commonly acquires resistance. We performed gene/protein expression, metabolomic and methylation analyses of isogenic AML cell lines sensitive or resistant to VEN, and identified the activation of RAS/MAPK pathway, leading to increased stability and higher levels of MCL-1 protein, as a major acquired mechanism of VEN resistance. MCL-1 sustained survival and maintained mitochondrial respiration in VEN-RE cells, which had impaired electron transport chain (ETC) complex II activity, and MCL-1 silencing or pharmacologic inhibition restored VEN sensitivity. In support of the importance of RAS/MAPK activation, we found by single-cell DNA sequencing rapid clonal selection of RAS-mutated clones in AML patients treated with VEN-containing regimens. In summary, these findings establish RAS/MAPK/MCL-1 and mitochondrial fitness as key survival mechanisms of VEN-RE AML and provide the rationale for combinatorial strategies effectively targeting these pathways.

Background B cells play a pivotal role in regulating the immune response. The induction of B cell-mediated immunosuppressive function requires B cell activating signals. However, the mechanisms by which activated B cells mediate T-cell suppression are not fully understood.Methods We investigated the potential contribution of metabolic activity of activated B cells to T-cell suppression by performing in vitro experiments and by analyzing clinical samples using mass cytometry and single-cell RNA sequencing.Results Here we show that following activation, B cells acquire an immunoregulatory phenotype and promote T-cell suppression by metabolic competition. Activated B cells induced hypoxia in T cells in a cell–cell contact dependent manner by consuming more oxygen via an increase in their oxidative phosphorylation (OXPHOS). Moreover, activated B cells deprived T cells of glucose and produced lactic acid through their high glycolytic activity. Activated B cells thus inhibited the mammalian target of rapamycin pathway in T cells, resulting in suppression of T-cell cytokine production and proliferation. Finally, we confirmed the presence of tumor-associated B cells with high glycolytic and OXPHOS activities in patients with melanoma, associated with poor response to immune checkpoint blockade therapy.Conclusions We have revealed for the first time the immunomodulatory effects of the metabolic activity of activated B cells and their possible role in suppressing antitumor T-cell responses. These findings add novel insights into immunometabolism and have important implications for cancer immunotherapy.

Introduction and purpose Soy as a rich source of isoflavones has become a focus of interest because of its positive health benefits on numerous diseases, particularly hormone-related cancers. The aim of this study was to present the current state of knowledge on the role of soy in the development of breast, ovarian, endometrial, and prostate gland cancer. A brief description of the state of knowledge Soy components reduce inflammation, stress oxidative and inhibit proliferation of breast, ovarian, endometrial, and prostate cancer cells. Isoflavones such as genistein, daidzein, S-equol via activation of estrogen receptors, inhibit aromatase synthesis and may decrease the risk of estrogen-dependent cancers. Moreover, soy food products have the potential toregulate molecular pathways of AR and reduce testosterone levels. It leads to a reduced risk of prostate cancer. Furthermore, increased consumption of soy protein and isoflavones decreased the risk of mortality from cancers. Conclusions Soy foods and their isoflavones are associated with reduced carcinogenesis. A higher amount of soy intake can have positive benefits for prevention of cancers including breast, prostate gland, endometrial and ovarian cancer.

Background Acute myeloid leukemia (AML) stem cells (LSCs) are capable of surviving current standard chemotherapy and are the likely source of deadly, relapsed disease. While stem cell transplant serves as proof-of-principle that AML LSCs can be eliminated by the immune system, the translation of existing immunotherapies to AML has been met with limited success. Consequently, understanding and exploiting the unique immune-evasive mechanisms of AML LSCs is critical.Methods Analysis of stem cell datasets and primary patient samples revealed CD200 as a putative stem cell–specific immune checkpoint overexpressed in AML LSCs. Isogenic cell line models of CD200 expression were employed to characterize the interaction of CD200+ AML with various immune cell subsets both in vitro and in peripheral blood mononuclear cell (PBMC)–humanized mouse models. CyTOF and RNA-sequencing were performed on humanized mice to identify novel mechanisms of CD200-mediated immunosuppression. To clinically translate these findings, we developed a fully humanized CD200 antibody (IgG1) that removed the immunosuppressive signal by blocking interaction with the CD200 receptor while also inducing a potent Fc-mediated response. Therapeutic efficacy of the CD200 antibody was evaluated using both humanized mice and patient-derived xenograft models.Results Our results demonstrate that CD200 is selectively overexpressed in AML LSCs and is broadly immunosuppressive by impairing cytokine secretion in both innate and adaptive immune cell subsets. In a PBMC-humanized mouse model, CD200+ leukemia progressed rapidly, escaping elimination by T cells, compared with CD200− AML. T cells from mice with CD200+ AML were characterized by an abundance of metabolically quiescent CD8+ central and effector memory cells. Mechanistically, CD200 expression on AML cells significantly impaired OXPHOS metabolic activity in T cells from healthy donors. Importantly, CD200 antibody therapy could eliminate disease in the presence of graft-versus-leukemia in immune competent mice and could significantly improve the efficacy of low-intensity azacitidine/venetoclax chemotherapy in immunodeficient hosts.Conclusions Overexpression of CD200 is a stem cell–specific marker that contributes to immunosuppression in AML by impairing effector cell metabolism and function. CD200 antibody therapy is capable of simultaneously reducing CD200-mediated suppression while also engaging macrophage activity. This study lays the groundwork for CD200-targeted therapeutic strategies to eliminate LSCs and prevent AML relapse.

Acute graft-vs.-host (GVHD) disease remains a common complication of allogeneic stem cell transplantation with very poor outcomes once the disease becomes steroid refractory. Mesenchymal stem cells (MSCs) represent a promising therapeutic approach for the treatment of GVHD, but so far this strategy has had equivocal clinical efficacy. Therapies using MSCs require optimization taking advantage of the plasticity of these cells in response to different microenvironments. In this study, we aimed to optimize cord blood tissue derived MSCs (CBti MSCs) by priming them using a regimen of inflammatory cytokines. This approach led to their metabolic reprogramming with enhancement of their glycolytic capacity. Metabolically reprogrammed CBti MSCs displayed a boosted immunosuppressive potential, with superior immunomodulatory and homing properties, even after cryopreservation and thawing. Mechanistically, primed CBti MSCs significantly interfered with glycolytic switching and mTOR signaling in T cells, suppressing T cell proliferation and ensuing polarizing toward T regulatory cells. Based on these data, we generated a Good Manufacturing Process (GMP) Laboratory protocol for the production and cryopreservation of primed CBti MSCs for clinical use. Following thawing, these cryopreserved GMP-compliant primed CBti MSCs significantly improved outcomes in a xenogenic mouse model of GVHD. Our data support the concept that metabolic profiling of MSCs can be used as a surrogate for their suppressive potential in conjunction with conventional functional methods to support their therapeutic use in GVHD or other autoimmune disorders.

Abnormally low level of interstitial oxygen, or hypoxia, is a hallmark of tumor microenvironment and a known promoter of cancer chemoresistance. Inside a solid tumor mass, the hypoxia stems largely from inadequate supply of oxygenated blood through sparse or misshapen tumor vasculature whilst oxygen utilization rates are low in typical tumor's glycolytic metabolism. In acute leukemias, however, markers of intracellular hypoxia such as increased pimonidazole adduct staining and HIF-1α stabilization are observed in advanced leukemic bone marrows (BM) despite an increase in BM vasculogenesis. We utilized intravital fast scanning two-photon phosphorescence lifetime imaging microscopy (FaST-PLIM) in a BCR-ABL B-ALL mouse model to image the extracellular oxygen concentrations (pO2) in leukemic BM, and we related the extracellular oxygen levels to intracellular hypoxia, vascular markers and local leukemia burden. We observed a transient increase in BM pO2 in initial disease stages with intermediate leukemia BM burden, which correlated with an expansion of blood-carrying vascular network in the BM. Yet, we also observed increased formation of intracellular pimonidazole adducts in leukemic BM at the same time. This intermediate stage was followed by a significant decrease of extracellular pO2 and further increase of intracellular hypoxia as leukemia cellularity overwhelmed BM in disease end-stage. Remarkably, treatment of leukemic mice with IACS-010759, a pharmacological inhibitor of mitochondrial Complex I, substantially increased pO2 in the BM with advanced B-ALL, and it alleviated intracellular hypoxia reported by pimonidazole staining. High rates of oxygen consumption by B-ALL cells were confirmed by Seahorse assay including in ex vivo cells. Our results suggest that B-ALL expansion in BM is associated with intense oxidative phosphorylation (OxPhos) leading to the onset of metabolic BM hypoxia despite increased BM vascularization. Targeting mitochondrial respiration may be a novel approach to counteract BM hypoxia in B-ALL and, possibly, tumor hypoxia in other OxPhos-reliant malignancies.

Acute myeloid leukemia (AML) is an aggressive group of cancers with high mortality rates and significant relapse risks. Current treatments are insufficient, and new therapies are needed. Recent discoveries suggest that AML may be particularly sensitive to chemotherapeutics that target mitochondria. To further investigate this sensitivity, six compounds that target mitochondria [IACS-010759, rotenone, cytarabine, etoposide, ABT-199 (venetoclax), and carbonyl cyanide m-chlorophenylhydrazone] were each paired with six compounds with other activities, including tyrosine kinase inhibitors (midostaurin and dasatinib), glycolytic inhibitors (2-deoxy-D-glucose, 3-bromopyruvate, and lonidamine), and the microtubule destabilizer vinorelbine. The 36 resulting drug combinations were tested for synergistic cytotoxicity against MOLM-13 and OCI-AML2 AML cell lines. Four combinations (IACS-010759 with vinorelbine, rotenone with 2-deoxy-D-glucose, carbonyl cyanide m-chlorophenylhydrazone with dasatinib, and venetoclax with lonidamine) showed synergistic cytotoxicity in both AML cell lines and were selective for tumor cells, as survival of healthy PBMCs was dramatically higher. Among these drug pairs, IACS-010759/vinorelbine decreased ATP level and impaired mitochondrial respiration and coupling efficiency most profoundly. Some of these four treatments were also effective in K-562, KU812 (chronic myelogenous leukemia) and CCRF-CEM, MOLT-4 (acute lymphoblastic leukemia) cells, suggesting that these treatments may have value in treating other forms of leukemia. Finally, two of the four combinations retained high synergy and strong selectivity in primary AML cells from patient samples, supporting the potential of these treatments for patients.

Dinucleotide analogs of the messenger RNA cap (m7GpppN) are useful research tools and have potential applications as translational inhibitors or reagents for modification of in vitro transcribed mRNAs. It has been previously reported that replacing the methyl group at the N7-position with benzyl (Bn) produces a dinucleotide cap with superior properties. Here, we followed up on this finding by synthesizing 17 novel Bn7GpppG analogs and determining their structure–activity relationship regarding translation and translational inhibition. The compounds were prepared in two steps, including selective N7-alkylation of guanosine 5′-monophosphate by arylmethyl bromide followed by coupling with imidazole-activated GDP, with total yields varying from 22% to 62%. The compounds were then evaluated by determining their affinity for eukaryotic translation initiation factor 4E (eIF4E), testing their susceptibility to decapping pyrophosphatase, DcpS—which is most likely the major cellular enzyme targeting this type of compound—and determining their translation inhibitory properties in vitro. We also synthesized mRNAs capped with the evaluated compounds and tested their translational properties in A549 cells. Our studies identified N7-(4-halogenbenzyl) substituents as promising modifications in the contexts of either mRNA translation or translational inhibition. Finally, to gain more insight into the consequences at the molecular level of N7-benzylation of the mRNA cap, we determined the crystal structures of three compounds with eIF4E.