Tumor-associated macrophages in osteosarcoma

A Novel Defined Necroptosis-Related Genes Prognostic Signature for Predicting Prognosis and Treatment of Osteosarcoma

Osteosarcoma (OS) is a frequent primary malignant bone tumor, with a poor prognosis. Necroptosis is strongly correlated with OS and may be an influential target for treating OS. This study's objective was to establish a necroptosis-related gene (NRG) prognostic signature that could predict OS prognosis and guide OS treatment. First, we identified 20 NRGs associated with OS survival based on the TARGET database. We then derived a 7 NRG prognostic signature. Our findings revealed that the 7 NRG prognostic signature performed well in predicting the survival of OS patients. We next analyzed differences in immunological status and immune cell infiltration. In addition, we examined the relationship between chemo/immunotherapeutic response and the 7-NRG prognostic signature. In addition, to probe the mechanisms underlying the NRG prognostic signature, we performed functional enrichment assays including GO and KEGG. Finally, CHMP4C was selected for functional experiments. Silencing CHMP4C prevented OS cells from proliferating, migrating, and invading. This 7-NRG prognostic signature seems to be an excellent predictor that can provide a fresh direction for OS treatment.

Role of macrophages and their exosomes in orthopedic diseases

Exosomes are vesicles with a lipid bilayer structure that carry various active substances, such as proteins, DNA, non-coding RNA, and nucleic acids; these participate in the immune response, tissue formation, and cell communication. Owing to their low immunogenicity, exosomes play a key role in regulating the skeletal immune environment. Macrophages are important immune cells that swallow various cellular and tissue fragments. M1-like and M2-like macrophages differentiate to play pro-inflammatory, anti-inflammatory, and repair roles following stimulation. In recent years, the increase in the population base and the aging of the population have led to a gradual rise in orthopedic diseases, placing a heavy burden on the social medical system and making it urgent to find effective solutions. Macrophages and their exosomes have been demonstrated to be closely associated with the pathogenesis and prognosis of orthopedic diseases. An in-depth understanding of their mechanisms of action and the interaction between them will be helpful for the future clinical treatment of orthopedic diseases. This review focuses on the mechanisms of action, diagnosis, and treatment of orthopedic diseases involving macrophages and their exosomes, including fracture healing, diabetic bone damage, osteosarcoma, and rheumatoid arthritis. In addition, we discuss the prospects and major challenges faced by macrophages and their exosomes in clinical practice.

Identification of a novel MYC target gene set signature for predicting the prognosis of osteosarcoma patients

Osteosarcoma is a primary malignant tumor found mainly in teenagers and young adults. Patients have very little long-term survival. MYC controls tumor initiation and progression by regulating the expression of its target genes; thus, constructing a risk signature of osteosarcoma MYC target gene set will benefit the evaluation of both treatment and prognosis. In this paper, we used GEO data to download the ChIP-seq data of MYC to obtain the MYC target gene. Then, a risk signature consisting of 10 MYC target genes was developed using Cox regression analysis. The signature indicates that patients in the high-risk group performed poorly. After that, we verified it in the GSE21257 dataset. In addition, the difference in tumor immune function among the low- and high-risk populations was compared by single sample gene enrichment analysis. Immunotherapy and prediction of response to the anticancer drug have shown that the risk signature of the MYC target gene set was positively correlated with immune checkpoint response and drug sensitivity. Functional analysis has demonstrated that these genes are enriched in malignant tumors. Finally, STX10 was selected for functional experimentation. STX10 silence has limited osteosarcoma cell migration, invasion, and proliferation. Therefore, these findings indicated that the MYC target gene set risk signature could be used as a potential therapeutic target and prognostic indicator in patients with osteosarcoma.

Reprogramming tumor-associated macrophages as a unique approach to target tumor immunotherapy

In the last ten years, it has become increasingly clear that tumor-infiltrating myeloid cells drive not just carcinogenesis via cancer-related inflammatory processes, but also tumor development, invasion, and metastasis. Tumor-associated macrophages (TAMs) in particular are the most common kind of leucocyte in many malignancies and play a crucial role in establishing a favorable microenvironment for tumor cells. Tumor-associated macrophage (TAM) is vital as the primary immune cell subset in the tumor microenvironment (TME).In order to proliferate and spread to new locations, tumors need to be able to hide from the immune system by creating an immune-suppressive environment. Because of the existence of pro-tumoral TAMs, conventional therapies like chemotherapy and radiotherapy often fail to restrain cancer growth. These cells are also to blame for the failure of innovative immunotherapies premised on immune-checkpoint suppression. Understanding the series of metabolic changes and functional plasticity experienced by TAMs in the complex TME will help to use TAMs as a target for tumor immunotherapy and develop more effective tumor treatment strategies. This review summarizes the latest research on the TAMs functional status, metabolic changes and focuses on the targeted therapy in solid tumors.

The Role of Tumor Microenvironment in Regulating the Plasticity of Osteosarcoma Cells

Osteosarcoma (OS) is a malignancy that is becoming increasingly common in adolescents. OS stem cells (OSCs) form a dynamic subset of OS cells that are responsible for malignant progression and chemoradiotherapy resistance. The unique properties of OSCs, including self-renewal, multilineage differentiation and metastatic potential, 149 depend closely on their tumor microenvironment. In recent years, the likelihood of its dynamic plasticity has been extensively studied. Importantly, the tumor microenvironment appears to act as the main regulatory component of OS cell plasticity. For these reasons aforementioned, novel strategies for OS treatment focusing on modulating OS cell plasticity and the possibility of modulating the composition of the tumor microenvironment are currently being explored. In this paper, we review recent studies describing the phenomenon of OSCs and factors known to influence phenotypic plasticity. The microenvironment, which can regulate OSC plasticity, has great potential for clinical exploitation and provides different perspectives for drug and treatment design for OS.

Circular RNAs: typical biomarkers for bone-related diseases

Bone is a connective tissue that has important functions in the human body. Cells and the extracellular matrix (ECM) are key components of bone and are closely related to bone-related diseases. However, the outcomes of conventional treatments for bone-related diseases are not promising, and hence it is necessary to elucidate the exact regulatory mechanisms of bone-related diseases and identify novel biomarkers for diagnosis and therapy. Circular RNAs (circRNAs) are single-stranded RNAs that form closed circular structures without a 5' cap or 3' tail and polycyclic adenylate tails. Due to their high stability, circRNAs have the potential to be typical biomarkers. Accumulating evidence suggests that circRNAs are involved in bone-related diseases, including osteoarthritis, osteoporosis, osteosarcoma, multiple myeloma, intervertebral disc degeneration, and rheumatoid arthritis. Herein, we summarize the recent research progress on the characteristics and functions of circRNAs, and highlight the regulatory mechanism of circRNAs in bone-related diseases.

Characterization of osteosarcoma subtypes mediated by macrophage-related genes and creation and validation of a risk score system to quantitatively assess the prognosis of osteosarcoma and reflect the tumor microenvironment

Background

Macrophages are the main immune components in the microenvironment of osteosarcoma. The treatment strategy centered on macrophages has become a hot topic to improve cancer treatment. However, the research on the role of macrophages in the treatment of osteosarcoma is still in its infancy.

Methods

The data of osteosarcoma samples were downloaded from the Therapeutically Applicable Research to Generate Effective Treatments (TARGET) and GSE21257 datasets, and the macrophage enrichment fraction of osteosarcoma samples in TARGET was calculated by single-sample gene set enrichment analysis (ssGSEA) method to screen macrophage-related genes for consensus clustering. Differential expression analysis, univariable Cox, and least absolute shrinkage and selection operator (LASSO) regression were conducted to select reliable predictors and create a risk score system. The GSE21257 dataset was used as a verification set to verify the accuracy of risk score system.

Results

We identified 2 osteosarcoma clusters mediated by 22 macrophage score-related genes, namely cluster 1 (C1) and cluster 2 (C2). Compared with C2, C1 had a significant advantage in prognosis, and the degree of immune cell infiltration in tumor microenvironment (TME) was significantly higher, the expression of immune checkpoint molecules was significantly enhanced, and the Tumor Immune Dysfunction and Exclusion (TIDE) score was also significantly down-regulated. A robust risk score system was presented and validated, which demonstrated accuracy and independence in assessing the risk of death of osteosarcoma. The risk score system could also monitor TME infiltration in osteosarcoma samples and showed a close relationship with osteosarcoma biology, including metastasis and immunity.

Conclusions

We identified 2 types of clusters mediated by macrophage-related genes and helped to analyze the cluster suitable for immunotherapy. A new prognostic risk score system was created to quantitatively evaluate the prognosis and TME of osteosarcoma, and to provide a new entry point for the design of personalized treatment.

A novel signature to guide osteosarcoma prognosis and immune microenvironment: Cuproptosis-related lncRNA

Objective

Osteosarcoma (OS) is a common bone malignancy with poor prognosis. We aimed to investigate the relationship between cuproptosis-related lncRNAs (CRLncs) and the survival outcomes of patients with OS.

Methods

Transcriptome and clinical data of 86 patients with OS were downloaded from The Cancer Genome Atlas (TCGA). The GSE16088 dataset was downloaded from the Gene Expression Omnibus (GEO) database. The 10 cuproptosis-related genes (CRGs) were obtained from a recently published article on cuproptosis in Science. Combined analysis of OS transcriptome data and the GSE16088 dataset identified differentially expressed CRGs related to OS. Next, pathway enrichment analysis was performed. Co-expression analysis obtained CRLncs related to OS. Univariate COX regression analysis and least absolute shrinkage and selection operator (LASSO) regression analysis were used to construct the risk prognostic model of CRLncs. The samples were divided evenly into training and test groups to verify the accuracy of the model. Risk curve, survival, receiver operating characteristic (ROC) curve, and independent prognostic analyses were performed. Next, principal component analysis (PCA) and t-distributed stochastic neighbor embedding (t-SNE) analysis were performed. Single-sample gene set enrichment analysis (ssGSEA) was used to explore the correlation between the risk prognostic models and OS immune microenvironment. Drug sensitivity analysis identified drugs with potential efficacy in OS. Real-time quantitative PCR, Western blotting, and immunohistochemistry analyses verified the expression of CRGs in OS. Real-time quantitative PCR was used to verify the expression of CRLncs in OS.

Results

Six CRLncs that can guide OS prognosis and immune microenvironment were obtained, including three high-risk CRLncs (AL645608.6, AL591767.1, and UNC5B-AS1) and three low-risk CRLncs (CARD8-AS1, AC098487.1, and AC005041.3). Immune cells such as B cells, macrophages, T-helper type 2 (Th2) cells, regulatory T cells (Treg), and immune functions such as APC co-inhibition, checkpoint, and T-cell co-inhibition were significantly downregulated in high-risk groups. In addition, we obtained four drugs with potential efficacy for OS: AUY922, bortezomib, lenalidomide, and Z.LLNle.CHO. The expression of LIPT1, DLAT, and FDX1 at both mRNA and protein levels was significantly elevated in OS cell lines compared with normal osteoblast hFOB1.19. The mRNA expression level of AL591767.1 was decreased in OS, and that of AL645608.6, CARD8-AS1, AC005041.3, AC098487.1, and UNC5B-AS1 was upregulated in OS.

Conclusion

CRLncs that can guide OS prognosis and the immune microenvironment and drugs that may have a potential curative effect on OS obtained in this study provide a theoretical basis for OS survival research and clinical decision-making.

Proteomic characterization of four subtypes of M2 macrophages derived from human THP-1 cells

Macrophages are widely distributed immune cells that contribute to tissue homeostasis. Human THP-1 cells have been widely used in various macrophage-associated studies, especially those involving pro-inflammatory M1 and anti-inflammatory M2 phenotypes. However, the molecular characterization of four M2 subtypes (M2a, M2b, M2c, and M2d) derived from THP-1 has not been fully investigated. In this study, we systematically analyzed the protein expression profiles of human THP-1-derived macrophages (M0, M1, M2a, M2b, M2c, and M2d) using quantitative proteomics approaches. The commonly and specially regulated proteins of the four M2 subtypes and their potential biological functions were further investigated. The results showed that M2a and M2b, and M2c and M2d have very similar protein expression profiles. These data could serve as an important resource for studies of macrophages using THP-1 cells, and provide a reference to distinguish different M2 subtypes in macrophage-associated diseases for subsequent clinical research.

Chemical characterization of a new sulfated polysaccharide from Gracilaria chouae and its activation effects on RAW264.7 macrophages

This study aimed to characterize the chemical composition of a new sulfated polysaccharide from the red alga Gracilaria chouae and evaluate its activation effects on RAW264.7 macrophages. It showed that the obtained G. chouae polysaccharide (GCP-3A) was a sulfated acidic polysaccharide with a molecular weight of 11.87 kDa. GCP-3A was composed of xylose, galactose, glucose, and mannose with a molar ratio of 3.00:29.28:0.63:0.45, and it contained α,β‍-glycosidic linkages. Scanning electron microscopy (SEM) and a Congo red test showed that it was a heterogeneous polysaccharide with irregular interwoven sheets and rods, and did not have a triple-helix conform‍ation. Furthermore, GCP-3A significantly promoted the proliferation of RAW264.7 macrophages and the secretion of nitric oxide (NO) in tests of 3-‍(4,‍5-dimethylthiahiazo-2-yl)‍-2,‍5-diphenytetrazoliumromide(MTT) and NO.