Single-cell resolution characterization of myeloid-derived cell states with implication in cancer outcome.

Tumor-associated myeloid-derived cells (MDCs) significantly impact cancer prognosis and treatment responses due to their remarkable plasticity and tumorigenic behaviors. Here, we integrate single-cell RNA-sequencing data from different cancer types, identifying 29 MDC subpopulations within the tumor microenvironment. Our analysis reveals abnormally expanded MDC subpopulations across various tumors and distinguishes cell states that have often been grouped together, such as TREM2+ and FOLR2+ subpopulations. Using deconvolution approaches, we identify five subpopulations as independent prognostic markers, including states co-expressing TREM2 and PD-1, and FOLR2 and PDL-2. Additionally, TREM2 alone does not reliably predict cancer prognosis, as other TREM2+ macrophages show varied associations with prognosis depending on local cues. Validation in independent cohorts confirms that FOLR2-expressing macrophages correlate with poor clinical outcomes in ovarian and triple-negative breast cancers. This comprehensive MDC atlas offers valuable insights and a foundation for futher analyses, advancing strategies for treating solid cancers.

Crosstalk between BCR-ABL and protease-activated receptor 1 (PAR1) suggests a novel target in chronic myeloid leukemia.

Chronic myeloid leukemia (CML) is a myeloproliferative neoplasm characterized by the presence of the Philadelphia chromosome, which generates the oncogene BCR-ABL1. Protease-activated receptor 1 (PAR1) is involved in tumor progression and angiogenesis. We have previously reported that PAR1 expression is elevated in human leukemias that display a more aggressive clinical behavior, including the blast crisis of CML. In this study, we analyzed the crosstalk between the oncoprotein BCR-ABL and PAR1 in CML. Leukemic cell lines transfected with the BCR-ABL1 oncogene showed significantly higher expression levels of PAR1 compared with that of wild-type counterparts. This phenomenon was reversed by treatment with tyrosine kinase inhibitors (TKIs). Conversely, treatment with the PAR1 antagonist SCH79797 inhibited BCR-ABL expression. The PAR1 antagonist induced apoptosis in a dose- and time-dependent manner. Higher vascular endothelial growth factor (VEGF) levels were observed in cells transfected with BCR-ABL1 than in their wild-type counterparts. VEGF expression was strongly inhibited after treatment with either TKIs or the PAR1 antagonist. Finally, we evaluated PAR1 expression in CML patients who were either in the blast or chronic phases and had either received TKI treatment or no treatment. A significant decrease in PAR1 expression was observed in treatment-responsive patients, as opposed to a significant increase in PAR1 expression levels in treatment-resistant patients. Patients classified as high risk according to the Sokal index showed higher PAR1 expression levels. Our results demonstrate the crosstalk between BCR-ABL and PAR1. These data may offer important insight into the development of new therapeutic strategies for CML.

A Rare Case of Relapsed Pediatric Acute Promyelocytic Leukemia with Skin Involvement by Myeloid Sarcoma.

BACKGROUND Acute promyelocytic leukemia (APL) is a very rare leukemia in children. Extramedullary involvement by APL has been reported in between 3-5% of cases, mainly associated with cases of relapse. A rare case of relapse of APL in a 9-year-old child is presented with skin involvement with myeloid sarcoma. CASE REPORT A 9-year-old male child was admitted to the Oncology Service of the hospital complaining of fever, progressive fatigue, oral petechiae with severe bleeding in the oral cavity. Bone marrow examination showed some promyelocytes. Flow cytometry showed 86% immature myeloid cells with the t(15;17) translocation, and molecular analysis showed expression of the PML/RARa fusion protein, which confirmed the diagnosis of APL. The patient completed a course of daunorubicin, cytarabine, and AII trans-retinoic acid (ATRA) with complete remission. After six months, the patient was re-admitted to hospital with a violaceous lesion on the scalp, with relapse of APL. Histological and immunohistochemistry of the lesion involving the skin of the scalp showed a myeloid sarcoma invading the dermis. CONCLUSIONS Myeloid sarcoma, also called granulocytic sarcoma, is an extramedullary tumor of immature myeloid cells, which very rarely presents in children with APL. The mechanisms that lead to myeloid sarcoma in children with APL and the possible association with ATRA therapy remain to be investigated.

[Immunopathology of chronic obstructive pulmonary disease]. / Inmunopatología de la enfermedad pulmonar obstructiva crónica.

Chronic obstructive pulmonary disease (COPD) is a common, preventable and treatable condition that has a complex pathophysiology and an even more complex immunopathological process. The purpose of this review was to analyze COPD immunopathological aspects, which was addressed by undertaking a literature search for the most relevant documents indexed in the PubMed database over the last 10 years. Different conclusions could be drawn: in COPD immunopathology there are immune and non-immune inflammatory changes with oxidative stress imbalance, there are alterations in the protease/anti-protease ratio caused by direct and indirect genetic and epigenetic-environmental defects; COPD produces irreversible tissue damage and chronic inflammation with tissue repair alteration, which induces chronic obstruction of the airway, bronchitis and systemic damage. Most common resulting comorbidities include cardiovascular disease, metabolic syndrome, osteoporosis, depression, musculoskeletal dysfunction, increased biological age, lung cancer and other types of malignancies. In the conception of COPD, recognizing that it is a non-transmittable and preventable disease is indispensable.

La enfermedad pulmonar obstructiva crónica (EPOC) es una enfermedad común, prevenible y tratable que presenta una fisiopatología compleja y un proceso inmunopatológico aún más complicado. El objetivo de esta revisión fue analizar los aspectos inmunopatológicos de la EPOC, para lo cual se llevó a una cabo una pesquisa bibliográfica de los documentos más relevantes indexados en la base de datos PubMed durante los últimos 10 años. Diversos aspectos pudieron concluirse: en la inmunopatología de la EPOC existen cambios inflamatorios, inmunológicos y no inmunológicos con un desequilibrio en el estrés oxidativo, así como alteraciones en la relación proteasas/antiproteasas debidas a efectos genéticos, epigenéticos, ambientales directos e indirectos. La EPOC produce daño tisular irreversible e inflamación crónica con alteración de la reparación tisular que induce obstrucción crónica de la vía aérea, bronquitis, enfisema y daño sistémico. Las comorbilidades resultantes más comunes son enfermedad cardiovascular, síndrome metabólico, osteoporosis, depresión, disfunción músculo esquelética, incremento de la edad biológica, cáncer pulmonar y otros tipos de neoplasias. En la concepción de la EPOC es indispensable reconocer que es una enfermedad no transmisible y prevenible.

Deploying Immunotherapy in Pancreatic Cancer: Defining Mechanisms of Response and Resistance.

The immune reaction to pancreatic ductal adenocarcinoma (PDAC) is a strong prognostic determinant of clinical outcomes and may be a promising therapeutic target. We use multiplex immunohistochemistry to illustrate distinct patterns of T-cell and myeloid cell infiltration seen in PDAC that have therapeutic implications and discuss the current state of immunotherapy in this disease. Based on collective findings from clinical and preclinical studies, two conceptual models have emerged for applying immunotherapy in PDAC that involve (1) restoring elements of T-cell immunosurveillance and (2) redirecting myeloid cells to condition tumors with increased sensitivity to cytotoxic therapies. Overall, the success of immunotherapy in PDAC will most likely rely on strategic combinations of therapies that are informed by well-designed correlative analyses that consider the spatial heterogeneity of immune responses detected in malignant tissues.

Porcine reproductive and respiratory syndrome type 1 viruses induce hypoplasia of erythroid cells and myeloid cell hyperplasia in the bone marrow of experimentally infected piglets independently of the viral load and virulence.

Porcine reproductive and respiratory syndrome viruses (PRRSV) present a wide phenotypic and genetic diversity. Experimental infections have demonstrated viral replication, including highly pathogenic strains (HP-PRRSV), in primary lymphoid organs such as the thymus. However, studies of the bone marrow are scarce but necessary to help elucidate the immunobiology of PRRSV strains of differing virulence. In this study, whereas viral RNA was detected within the bone marrow of animals experimentally infected with both low virulent Lelystad (LV) and 215-06 PRRSV-1 strains and with the highly virulent SU1-bel strain, PRRSV positive cells were only occasionally detected in one SU1-bel infected animal. PRRSV RNA levels were associated to circulating virus with the highest levels detected in LV-infected pigs. At 3 dpi, a decrease in the proportion of haematopoietic tissue and number of erythroid cells in all infected groups was associated with an increase in TUNEL or cleaved caspase 3 labelling and higher counts of myeloid cells compared to control. The expression of IL-1α and IL-6 was elevated at the beginning of the infection in all infected animals. The expression of TNF-α was increased at the end of the study in all infected groups with respect to control. Different PRRSV-1 strains induced, presummably by indirect mechanisms and independently of viral load and strain virulence, moderate and sustained hypoplasia of erythroid cells and myeloid cell hyperplasia at early stages of infection. These changes were paralleled by a peak in the local expression of IL-1α, IL-6 and TNF-α in all infected groups.

Overcoming Therapeutic Resistance by Targeting Cancer Inflammation.

Tumor-infiltrating myeloid cells are a prominent feature of most solid malignancies. This inflammatory immune response, driven by tumor-intrinsic signaling pathways, is a major checkpoint to therapeutic efficacy achieved with immunotherapy and standard cytotoxic therapies. To overcome therapeutic resistance mediated by cancer inflammation, ongoing clinical trials are evaluating strategies that (1) deplete myeloid cells from tumors, (2) inhibit tumor-promoting properties of myeloid cells, and (3) redirect myeloid cells with tumor-inhibitory activity.

First proposed panels on acute leukemia for four-color immunophenotyping by flow cytometry from the Brazilian group of flow cytometry-GBCFLUX.

Multiparameter flow cytometry is a highly sensitive, fast, and specific diagnostic technology with a wide range of applicability in hematology. Although well-established eight-color immunophenotyping panels are already available, most Brazilian clinical laboratories are equipped with four-color flow cytometer facilities. Based on this fact, the Brazilian Group of Flow Cytometry (Grupo Brasileiro de Citometria de Fluxo, GBCFLUX) for standardization of clinical flow cytometry has proposed an antibody panel designed to allow precise diagnosis and characterization of acute leukemia (AL) within resource-restricted areas. Morphological analysis of bone marrow smears, together with the screening panel, is mandatory for the primary identification of AL. The disease-oriented panels proposed here are divided into three levels of recommendations (mandatory, recommendable, and optional) in order to provide an accurate final diagnosis, as well as allow some degree of flexibility based on available local resources and patient-specific needs. The proposed panels will be subsequently validated in an interlaboratory study to evaluate its effectiveness on the diagnosis and classification of AL. (Assoc editor comm. 2).

Influence of aberrant myeloid expression on acute lymphoblastic leukemia in children and adolescents from Maranhão, Brazil.

The aim of this study was to evaluate myeloid expression in acute lymphoblastic leukemia (ALL) in children and adolescents who had been referred to the Oncology Department in a hospital in the State of Maranhão based on demographic, laboratory, and clinical data. Myeloid expression was evaluated in 65 patients under 18 years of age who were diagnosed with morphological, cytochemical, and immunophenotypes of ALL. Demographic, laboratory (hemogram), and clinical variables were obtained from medical records. The sample was divided into groups with and without anomalous myeloid expression to analyze the variables. Myeloid expression was observed in 49.2% of the sample. Platelet count was significantly lower in the group of children without aberrant myeloid expression (33,627 platelets/mm(3), P = 0.01). A total of 88.9% of children with B-cell ALL without myeloid expression showed less than 50,000 platelets/mm(3) (P = 0.01). Thus, platelet count may be an important parameter in the diagnosis of children with ALL without myeloid aberrant expression and may indicate a greater risk of bleeding during treatment in this group.

Dietary supplementation with Lactobacilli improves emergency granulopoiesis in protein-malnourished mice and enhances respiratory innate immune response.

This work studied the effect of protein malnutrition on the hemato-immune response to the respiratory challenge with Streptococcus pneumoniae and evaluated whether the dietary recovery with a probiotic strain has a beneficial effect in that response. Three important conclusions can be inferred from the results presented in this work: a) protein-malnutrition significantly impairs the emergency myelopoiesis induced by the generation of the innate immune response against pneumococcal infection; b) repletion of malnourished mice with treatments including nasally or orally administered Lactobacillus rhamnosus CRL1505 are able to significantly accelerate the recovery of granulopoiesis and improve innate immunity and; c) the immunological mechanisms involved in the protective effect of immunobiotics vary according to the route of administration. The study demonstrated that dietary recovery of malnourished mice with oral or nasal administration of L. rhamnosus CRL1505 improves emergency granulopoiesis and that CXCR4/CXCR12 signaling would be involved in this effect. Then, the results summarized here are a starting point for future research and open up broad prospects for future applications of probiotics in the recovery of immunocompromised malnourished hosts.

Myeloid-derived suppressor cells and associated events in urethane-induced lung cancer.

OBJECTIVES: Myeloid-derived suppressor cells contribute to the immunosuppressive microenvironment during tumor development and limit the efficacy of cancer immunotherapy. Identifying myeloid-derived suppressor cells and associated factors is the first step in creating strategies to reverse the suppressive effects of these cells on the immune system. METHODS: To induce lung cancer, we administered 2 doses of urethane to BALB/c mice and observed these animals for 120 days. After this period, we evaluated the percentage of myeloid-derived suppressor cells in the blood, lung and bone marrow. The expression of alpha-smooth muscle actin, transforming growth factor-ß, Toll-like receptor 2, Toll-like receptor 4, and interleukin-6 was also determined in the lung tissue. RESULTS: Myeloid-derived suppressor cells were increased in all evaluated tissues after lung cancer development in association with increased Toll-like receptor 4 expression and decreased interleukin-6 expression in the lung. We observed alpha-smooth muscle actin and transforming growth factor-ß expression in lung nodules. CONCLUSIONS: We believe that the early diagnosis of cancer through determining the blood levels of myeloid-derived suppressor cells followed by the depletion of these cells should be further investigated as a possible approach for cancer treatment.

Myeloid-derived suppressor cells and associated events in urethane-induced lung cancer

OBJECTIVES: Myeloid-derived suppressor cells contribute to the immunosuppressive microenvironment during tumor development and limit the efficacy of cancer immunotherapy. Identifying myeloid-derived suppressor cells and associated factors is the first step in creating strategies to reverse the suppressive effects of these cells on the immune system. METHODS: To induce lung cancer, we administered 2 doses of urethane to BALB/c mice and observed these animals for 120 days. After this period, we evaluated the percentage of myeloid-derived suppressor cells in the blood, lung and bone marrow. The expression of alpha-smooth muscle actin, transforming growth factor-β, Toll-like receptor 2, Toll-like receptor 4, and interleukin-6 was also determined in the lung tissue. RESULTS: Myeloid-derived suppressor cells were increased in all evaluated tissues after lung cancer development in association with increased Toll-like receptor 4 expression and decreased interleukin-6 expression in the lung. We observed alpha-smooth muscle actin and transforming growth factor-β expression in lung nodules. CONCLUSIONS: We believe that the early diagnosis of cancer through determining the blood levels of myeloid-derived suppressor cells followed by the depletion of these cells should be further investigated as a possible approach for cancer treatment. .

Infiltration of a mixture of immune cells may be related to good prognosis in patients with differentiated thyroid carcinoma.

OBJECTIVE: Immune responses against differentiated thyroid carcinomas (DTC) have long been recognized. We aimed to investigate the role of immune cell infiltration in the progression of DTC. DESIGN: We studied 398 patients - 253 with papillary and 13 with follicular thyroid cancers, as well as 132 with nonmalignant tissues. PATIENTS AND MEASUREMENTS: Immune cell infiltration was identified using CD3, CD4, CD8, CD20, CD68 and FoxP3 immunohistochemical markers. In addition, we assessed colocalization of CD4 and IL-17 to identify Th17 lymphocytic infiltration and colocalization of CD33 and CD11b to identify infiltration of myeloid-derived suppressor cells (MDSC). RESULTS: Immune cells infiltrated malignant tissues more often than benign lesions. The presence of chronic lymphocytic thyroiditis (CLT) concurrent to DTC, CD68+, CD4+, CD8+, CD20+, FoxP3+ and Th17 lymphocytes but not MDSCs was associated with clinical and pathological features of lower tumour aggressiveness and a more favourable patient outcome. A log-rank test confirmed an association between concurrent CLT, tumour-associated macrophage infiltration, and CD8+ lymphocytes and an increased in disease-free survival, suggesting that evidence of these immune reactions is associated with a favourable prognosis. CONCLUSION: Our data suggest that the tumour or peri-tumoural microenvironment may act to modify the observed pattern of immune response. Immune cell infiltration and the presence of concurrent CLT helped characterize specific tumour histotypes associated with favourable prognostic features.

Computerized texture analysis of atypical immature myeloid precursors in patients with myelodysplastic syndromes: an entity between blasts and promyelocytes.

BACKGROUND: Bone marrow (BM) blast count is an essential parameter for classification and prognosis of myelodysplastic syndromes (MDS). However, a high degree of cell atypias in bone marrow hemopoietic cells may be found in this group of clonal disorders, making it difficult to quantify precisely myeloblasts, and to distinguish them from promyelocytes and atypical immature myeloid precursors. Our aim was to investigate whether computerized image analysis of routine cytology would help to characterize these cells. METHODS: In May-Grünwald-Giemsa stained BM smears of 30 newly diagnosed MDS patients and 19 cases of normal BM, nuclei of blasts and promyelocytes were digitalized and interactively segmented. The morphological classification of the cells was done by consensus of two observers. Immature granulocytic precursors, which could not be clearly classified either as blasts or promyelocytes, were called "atypic myeloid precursors". Nuclear morphometry and texture features derived from the co-occurrence matrix and fractal dimension (FD) were calculated. RESULTS: In normal BM, when compared to myeloblasts, nuclei of promyelocytes showed significant increase in perimeter and local texture homogeneity and a decrease in form factor, chromatin gray levels, Haralick's entropy, inertia, energy, contrast, diagonal moment, cluster prominence, the fractal dimension according to Minkowski and its goodness-of-fit. Compared to normal myeloblast nuclei, the chromatin texture of MDS myeloblasts revealed higher local homogeneity and goodness-of-fit of the FD, but lower values of entropy, contrast, diagonal moment, and fractal dimension. The same differences were found between nuclei of normal promyelocytes and those of MDS. Nuclei of atypical myeloid precursors showed intermediate characteristics between those of blasts and promyelocytes according to the quantitative features (perimeter, form factor, gray level and its standard deviation), but were similar to promyelocytes according to the texture variables inertia, energy, contrast, diagonal moment, cluster prominence, and Minkowski's fractal dimension. CONCLUSION: BM atypical immature myeloid precursors are difficult to be correctly classified in routine cytology. Although their cytoplasm is more similar to that of myeloblasts, computerized texture analysis indicates a nuclear chromatin remodeling more close to the promyelocyte, thus indicating an asynchronous intermediate maturation stage between blast and promyelocyte.

Identification of myeloid-derived suppressor cells and T regulatory cells in lung microenvironment after Urethane-induced lung tumor.

Tumor growth occurs by the imbalance between cells with effector function and cells with suppressor/regulatory functions. To investigate this scenario we administered the chemical carcinogen Urethane in BALB/c mice and followed these animals during 120 days to observe lung tumor development. In another set of experiments the same protocol was performed with the harvest of spleen, lung and blood at 20 and 30 days after Urethane injection. The lung was used for histology, spleen cells were evaluated for IFN-γ production, and serum nitrite was measured as an indirect form of nitric oxide (NO) evaluation. The spleen and lung-infiltrating cells were evaluated by flow cytometry for CD11b+Gr-1+ myeloid suppressor cells and CD4+FoxP3+ T regulatory cells. Urethane led to lung nodules development after 120 days and the time point evaluation showed that splenocytes stimulated ex vivo expressed higher levels of IFN-γ 20 days after the chemical injection. Also, the level of nitric oxide in serum was higher after 20 days of Urethane injection. There was no statistical difference in spleen cells percentages for CD11b+Gr-1+ and CD4+Foxp3+ in all groups. However, lung-infiltrating cells presented early (20 days) a higher expression of CD11b+Gr-1+ suggesting suppression at this site. In conclusion, it was possible to observe two distinct events at the very early time point after Urethane injection. In periphery there was an increase at the effector immune response (as depicted by IFN-γ-producing cells) and in tumor development site there was an increase at the suppressor cell (CD11b+Gr-1+) phenotype. Suppressor/regulatory cells are targets for cancer therapy.

Inhibition of tumor-induced myeloid-derived suppressor cell function by a nanoparticulated adjuvant.

The interaction between cancer vaccine adjuvants and myeloid-derived suppressor cells (MDSCs) is currently poorly understood. Very small size proteoliposomes (VSSP) are a nanoparticulated adjuvant under investigation in clinical trials in patients with renal carcinoma, breast cancer, prostate cancer, and cervical intraepithelial neoplasia grade III. We found that VSSP adjuvant induced a significant splenomegaly due to accumulation of CD11b(+)Gr-1(+) cells. However, VSSP-derived MDSCs showed a reduced capacity to suppress both allogeneic and Ag-specific CTL response compared with that of tumor-induced MDSCs. Moreover, splenic MDSCs isolated from tumor-bearing mice treated with VSSP were phenotypically more similar to those isolated from VSSP-treated tumor-free mice and much less suppressive than tumor-induced MDSCs, both in vitro and in vivo. Furthermore, different from dendritic cell vaccination, inoculation of VSSP-based vaccine in EG.7-OVA tumor-bearing mice was sufficient to avoid tumor-induced tolerance and stimulate an immune response against OVA Ag, similar to that observed in tumor-free mice. This effect correlated with an accelerated differentiation of MDSCs into mature APCs that was promoted by VSSP. VSSP used as a cancer vaccine adjuvant might thus improve antitumor efficacy not only by stimulating a potent immune response against tumor Ags but also by reducing tumor-induced immunosuppression.