Explore the vast range of titles available.

Cancer-associated myeloid cells due to their plasticity play dual roles in both promoting and inhibiting tumor progression. Myeloid cells with immunosuppressive properties play a critical role in anti-cancer immune regulation. Cells of different origin, such as tumor associated macrophages (TAMs), tumor associated neutrophils (TANs), myeloid derived suppressor cells (also called MDSCs) and eosinophils are often expanded in cancer patients and significantly influence their survival, but also the outcome of anti-cancer therapies. For this reason, the variety of preclinical and clinical studies to modulate the activity of these cells have been conducted, however without successful outcome to date. In this review, pro-tumor activity of myeloid cells, myeloid cell-specific therapeutic targets, in vivo studies on myeloid cell re-polarization and the impact of myeloid cells on immunotherapies/genetic engineering are addressed. This paper also summarizes ongoing clinical trials and the concept of chimeric antigen receptor macrophage (CAR-M) therapies, and suggests future research perspectives, offering new opportunities in the development of novel clinical treatment strategies.

Background Calcium (Ca 2+ ) signaling regulates various vital cellular functions, including integrin activation and cell migration. Store-operated calcium entry (SOCE) via calcium release-activated calcium (CRAC) channels represents a major pathway for Ca 2+ influx from the extracellular space in multiple cell types. The impact of JAK2-V617F and CALR mutations which are disease initiating in myeloproliferative neoplasms (MPN) on SOCE, calcium flux from the endoplasmic reticulum (ER) to the cytosol, and related key signaling pathways in the presence or absence of erythropoietin (EPO) or thrombopoietin (TPO) is poorly understood. Thus, this study aimed to elucidate the effects of these mutations on the aforementioned calcium dynamics, in cellular models of MPN. Methods Intracellular Ca 2+ levels were measured over a time frame of 0–1080 s in Fura-2 AM labeled myeloid progenitor 32D cells expressing various mutations (JAK2-WT/EpoR, JAK2-V617F/EpoR; CALR-WT/MPL, CALR-ins5/MPL, and del52/MPL). Basal Ca 2+ concentrations were assessed from 0–108 s. Subsequently, cells were stimulated with EPO/TPO in Ca 2+ -free Ringer solution, measuring Ca 2+ levels from 109–594 s (store depletion). Then, 2 mM of Ca 2+ buffer resembling physiological concentrations was added to induce SOCE, and Ca 2+ levels were measured from 595–1080 s. Fura-2 AM emission ratios (F340/380) were used to quantify the integrated Ca 2+ signal. Statistical significance was assessed by unpaired Student's t-test or Mann–Whitney-U-test, one-way or two-way ANOVA followed by Tukey's multiple comparison test. Results Following EPO stimulation, the area under the curve (AUC) representing SOCE significantly increased in 32D-JAK2-V617F cells compared to JAK2-WT cells. In TPO-stimulated CALR cells, we observed elevated Ca 2+ levels during store depletion and SOCE in CALR-WT cells compared to CALR-ins5 and del52 cells. Notably, upon stimulation, key components of the Ca 2+ signaling pathways, including PLCγ-1 and IP3R, were differentially affected in these cell lines. Hyper-activated PLCγ-1 and IP3R were observed in JAK2-V617F but not in CALR mutated cells. Inhibition of calcium regulatory mechanisms suppressed cellular growth and induced apoptosis in JAK2-V617F cells. Conclusions This report highlights the impact of JAK2 and CALR mutations on Ca 2+ flux (store depletion and SOCE) in response to stimulation with EPO and TPO. The study shows that the JAK2-V617F mutation strongly alters the regulatory mechanism of EpoR/JAK2-dependent intracellular calcium balance, affecting baseline calcium levels, EPO-induced calcium entry, and PLCγ-1 signaling pathways. Our results reveal an important role of calcium flux in the homeostasis of JAK2-V617F positive cells.

Background The JAK2-V617F mutation is the most frequent driver mutation in a group of malignant hematopoietic disorders called myeloproliferative neoplasms (MPN). JAK2-V617F is a somatic mutation originating in a hematopoietic stem cell and results in constitutively activated JAK-STAT signaling. High levels of pro-inflammatory cytokines in the blood are a hallmark of MPN patients and are a key factor in the severe clinical symptoms seen in these patients. The molecular mechanisms underlying the up-regulation of inflammatory cytokines in JAK2-V617F mutated hematopoietic cells remain to be elucidated. Methods 32D myeloid progenitor cells expressing JAK2-wildtype (WT) and JAK2-V617F, respectively were employed. In addition, primary hematopoietic cells from the JAK2-V617F knock-in MPN mouse model were investigated. Integrin outside-in signaling upon binding of cells to the adhesion molecules VCAM-1/ICAM-1 was characterized by Western blotting of phosphorylated FAK, STAT3, p65, SYK and JNK. Regulation of mRNA and protein expression of IL-1α, IL-1β, IL-6, TNF and CXCL10 was measured by qPCR and ELISA. RNAseq and DNA methylation analysis in primary mouse JAK2-V617F granulocytes was performed. In JAK2-V617F knock-in mice, anti-integrin treatment was applied to evaluate the impact of activated integrin signaling on IL-1 blood levels in vivo. Results Integrin stimulation via the adhesion molecules VCAM-1/ICAM-1 activated integrin outside-in signaling including FAK, SYK, NFκB, and JNK. This induced strong mRNA expression of IL-1α, IL-1β, IL-6, TNF and CXCL10. In 32D cells, the presence of the JAK2-V617F mutation further increased VCAM-1/ICAM-1-induced mRNA and protein levels of IL-1α and IL-1β, and active caspase 1 expression. In primary granulocytes, integrin stimulation resulted in an activated mRNA signature of inflammatory cytokines. Consistent with the mRNA results, adhesion to VCAM-1/ICAM-1 induced an increase in intracellular IL-1α and IL-1β protein levels in 32D cells. However, in primary hematopoietic cells, up-regulation of inflammatory cytokines was not observed at the protein level in vitro, whereas, in vivo, blocking of integrin binding to VCAM-1/ICAM-1 was sufficient to reduce elevated IL-1α levels in the blood of JAK2-V617F mice. Conclusions We conclude that integrin stimulation via the adhesion molecules VCAM-1/ICAM-1 activates integrin outside-in signaling, leading to the up-regulation of pro-inflammatory cytokines in both JAK2-mutated and non-mutated mouse hematopoietic cells.

Background Neutrophils play a crucial role in inflammation and in the increased thrombotic risk in myeloproliferative neoplasms (MPNs). We have investigated how neutrophil-specific expression of JAK2-V617F or CALRdel re-programs the functions of neutrophils. Methods Ly6G-Cre JAK2-V617F and Ly6G-Cre CALRdel mice were generated. MPN parameters as blood counts, splenomegaly and bone marrow histology were compared to wild-type mice. Megakaryocyte differentiation was investigated using lineage-negative bone marrow cells upon in vitro incubation with TPO/IL-1β. Cytokine concentrations in serum of mice were determined by Mouse Cytokine Array. IL-1α expression in various hematopoietic cell populations was determined by intracellular FACS analysis. RNA-seq to analyse gene expression of inflammatory cytokines was performed in isolated neutrophils from JAK2-V617F and CALR-mutated mice and patients. Bioenergetics of neutrophils were recorded on a Seahorse extracellular flux analyzer. Cell motility of neutrophils was monitored in vitro (time lapse microscopy), and in vivo (two-photon microscopy) upon creating an inflammatory environment. Cell adhesion to integrins, E-selectin and P-selection was investigated in-vitro. Statistical analysis was carried out using GraphPad Prism. Data are shown as mean ± SEM. Unpaired, two-tailed t-tests were applied. Results Strikingly, neutrophil-specific expression of JAK2-V617F, but not CALRdel, was sufficient to induce pro-inflammatory cytokines including IL-1 in serum of mice. RNA-seq analysis in neutrophils from JAK2-V617F mice and patients revealed a distinct inflammatory chemokine signature which was not expressed in CALR-mutant neutrophils. In addition, IL-1 response genes were significantly enriched in neutrophils of JAK2-V617F patients as compared to CALR-mutant patients. Thus, JAK2-V617F positive neutrophils, but not CALR-mutant neutrophils, are pathogenic drivers of inflammation in MPN. In line with this, expression of JAK2-V617F or CALRdel elicited a significant difference in the metabolic phenotype of neutrophils, suggesting a stronger inflammatory activity of JAK2-V617F cells. Furthermore, JAK2-V617F, but not CALRdel, induced a VLA4 integrin-mediated adhesive phenotype in neutrophils. This resulted in reduced neutrophil migration in vitro and in an inflamed vessel. This mechanism may contribute to the increased thrombotic risk of JAK2-V617F patients compared to CALR-mutant individuals. Conclusions Taken together, our findings highlight genotype-specific differences in MPN-neutrophils that have implications for the differential pathophysiology of JAK2-V617F versus CALR-mutant disease.

Dietary energy restriction (DER) has been well established as a potent anticancer strategy. Non-adoption of restricted diet for an extended period has limited its practical implementation in humans with a compelling need to develop agents that mimic effects similar to DER, without reduction in actual dietary intake. Glycolytic inhibitor, 2-deoxy-D-glucose (2-DG), has recently been shown to possess potential as an energy restriction mimetic agent (ERMA). In the present study we evaluated the effect of dietary 2-DG administration on a mouse tumor model, with a focus on several potential mechanisms that may account for the inhibition of tumorigenesis. Swiss albino strain 'A' mice were administered with 0.2% and 0.4% w/v 2-DG in drinking water for 3 months prior to tumor implantation (Ehrlich's ascites carcinoma; EAC) and continued till the termination of the study with no adverse effects on general physiology and animal growth. Dietary 2-DG significantly reduced the tumor incidence, delayed the onset, and compromised the tumor growth along with enhanced survival. We observed reduced blood glucose and serum insulin levels along with decreased proliferating cell nuclear antigen (PCNA) and bromodeoxyuridine positive (BrdU+) tumor cells in 2-DG fed mice. Also, reduced levels of certain key players of metabolic pathways such as phosphatidylinositol 3-kinase (PI3K), phosphorylated-Akt and hypoxia inducible factor-1 alpha (HIF-1α) were also noted in tumors of 2-DG fed mice. Further, decrease in CD4+/CD8+ ratio and T-regulatory cells observed in 2-DG fed mice suggested enhanced antitumor immunity and T cell effector function. These results strongly suggest that dietary 2-DG administration in mice, at doses easily achievable in humans, suitably modulates several pleotrophic factors mimicking DER and inhibits tumorigenesis, emphasizing the use of ERMAs as a promising cancer preventive strategy.

Chronic lymphocytic leukemia (CLL) is characterized by the accumulation of clonal B cells. Although targeted therapies have improved outcomes, resistance remains a challenge, particularly in high-risk patients with TP53 mutations or unmutated immunoglobulin heavy-chain variable region (IGHV) genes (U-CLL). Ferroptosis, a regulated, iron-dependent form of cell death, may represent an exploitable vulnerability in CLL; however, its mechanisms and clinical relevance remain poorly understood. Here, we identified IGHV status and microenvironmental cues as determinants of ferroptosis sensitivity. Using CLL cell lines, patient samples, and in vivo models, we show that CLL cells exhibit elevated basal levels of lipid peroxides and labile iron, predisposing them to ferroptosis. However, stromal interactions enhance cystine import and glutathione synthesis, thereby mitigating susceptibility to ferroptosis. Mechanistically, BTK inhibition sensitizes CLL cells to ferroptosis by increasing the transferrin receptor (TFRC, CD71) and increasing the intracellular Fe²⁺ level. High TFRC expression was associated with improved survival in two independent CLL patient cohorts, supporting its therapeutic and prognostic relevance. Combining ibrutinib with the GPX4 inhibitor RSL3 enhances ferroptosis and improves antileukemic efficacy in vivo. CLL cells with mutated IGHV genes (M-CLL) display greater TFRC expression and ferroptosis sensitivity than U-CLL cells do. This resistance can be overcome by ibrutinib-mediated TFRC induction or via metabolic targeting of fatty acid metabolism. Notably, ACSL1 is selectively upregulated in U-CLL cells and represents a targetable metabolic enhancer of ferroptosis sensitivity, as shown in vivo. Our findings reveal that TFRC and ACSL1 are functionally distinct yet targetable nodes that govern ferroptosis vulnerability in CLL patients and may guide novel therapeutic strategies for high-risk patients.

Myeloproliferative neoplasms (MPNs), a group of malignant hematological disorders, occur as a consequence of somatic mutations in the hematopoietic stem cell compartment and show excessive accumulation of mature myeloid cells in the blood. A major cause of morbidity and mortality in these patients is the marked prothrombotic state leading to venous and arterial thrombosis, including myocardial infarction (MI), deep vein thrombosis (DVT), and strokes. Additionally, many MPN patients suffer from inflammation-mediated constitutional symptoms, such as fever, night sweats, fatigue, and cachexia. The chronic inflammatory syndrome in MPNs is associated with the up-regulation of various inflammatory cytokines in patients and is involved in the formation of the so-called MPN thromboinflammation. JAK2-V617F, the most prevalent mutation in MPNs, has been shown to activate a number of integrins on mature myeloid cells, including granulocytes and erythrocytes, which increase adhesion and drive venous thrombosis in murine knock-in/out models. This review aims to shed light on the current understanding of thromboinflammation, involvement of neutrophils in the prothrombotic state, plausible molecular mechanisms triggering the process of thrombosis, and potential novel therapeutic targets for developing effective strategies to reduce the MPN disease burden.

Bleomycin (BLM) is an effective curative option in the management of several malignancies including pleural effusions; but pulmonary toxicity, comprising of pneumonitis and fibrosis, poses challenge in its use as a front-line chemotherapeutic. Although Amifostine has been found to protect lungs from the toxic effects of radiation and BLM, its application is limited due to associated toxicity and unfavorable route of administration. Therefore, there is a need for selective, potent, and safe anti-fibrotic drugs. The current study was undertaken to assess the protective effects of DRDE-30, an analog of Amifostine, on BLM-induced lung injury in C57BL/6 mice. Whole body micro- computed tomography (CT) was used to non-invasively observe tissue damage, while broncheo-alveolar lavage fluid (BALF) and lung tissues were assessed for oxidative damage, inflammation and fibrosis. Changes in the lung density revealed by micro-CT suggested protection against BLM-induced lung injury by DRDE-30, which correlated well with changes in lung morphology and histopathology. DRDE-30 significantly blunted BLM-induced oxidative stress, inflammation and fibrosis in the lungs evidenced by reduced oxidative damage, endothelial barrier dysfunction, Myeloperoxidase (MPO) activity, pro-inflammatory cytokine release and protection of tissue architecture, that could be linked to enhanced anti-oxidant defense system and suppression of redox-sensitive pro-inflammatory signaling cascades. DRDE-30 decreased the BLM-induced augmentation in BALF TGF-β and lung hydroxyproline levels, as well as reduced the expression of the mesenchymal marker α-smooth muscle actin (α-SMA), suggesting the suppression of epithelial to mesenchymal transition (EMT) as one of its anti-fibrotic effects. The results demonstrate that the Amifostine analog, DRDE-30, ameliorates the oxidative injury and lung fibrosis induced by BLM and strengthen its potential use as an adjuvant in alleviating the side effects of BLM.

Background: Hepatocellular carcinoma (HCC) represents a major health burden with limited curative treatment options. There is a substantial unmet need to develop innovative approaches to impact the progression of advanced HCC. Haprolid is a novel natural component isolated from myxobacteria. Haprolid has been reported as a potent selective cytotoxin against a panel of tumor cells in recent studies including HCC cells. The aims of this study are to evaluate the antitumor effect of haprolid in HCC and to understand its underlying molecular mechanisms. Methods: The efficacy of haprolid was evaluated in human HCC cell lines (Huh-7, Hep3B and HepG2) and xenograft tumors (NMRI-Foxn1nu mice with injection of Hep3B cells). Cytotoxic activity of haprolid was determined by the WST-1 and crystal violet assay. Wound healing, transwell and tumorsphere assays were performed to investigate migration and invasion of HCC cells. Apoptosis and cell-cycle distribution were measured by flow cytometry. The effects of haprolid on the Rb/E2F and Akt/mTOR pathway were examined by immunoblotting and immunohistochemistry. Results: haprolid treatment significantly inhibited cell proliferation, migration and invasion in vitro. The epithelial–mesenchymal transition (EMT) was impaired by haprolid treatment and the expression level of N-cadherin, vimentin and Snail was downregulated. Moreover, growth of HCC cells in vitro was suppressed by inhibition of G1/S transition, and partially by induction of apoptosis. The drug induced downregulation of cell cycle regulatory proteins cyclin A, cyclin B and CDK2 and induced upregulation of p21 and p27. Further evidence showed that these effects of haprolid were associated with Rb/E2F downregulation and Akt/mTOR inhibition. Finally, in vivo nude mice experiments demonstrated significant inhibition of tumor growth upon haprolid treatment. Conclusion: Our results show that haprolid inhibits the growth of HCC through dual inhibition of Rb/E2F and Akt/mTOR pathways. Therefore, haprolid might be considered as a new and promising candidate for the palliative therapy of HCC.