Transcriptome-based network analysis related to M2-like tumor-associated macrophage infiltration identified VARS1 as a potential target for improving melanoma immunotherapy efficacy

In vitro study of cold atmospheric plasma-activated liquids inhibits malignant melanoma by affecting macrophage polarization through the ROS/JAK2/STAT1 pathway

Melanoma is a prevalent malignant skin tumor known for its high invasive ability and a high rate of metastasis, making clinical treatment exceptionally challenging. Tumor-associated macrophages (TAMs) are the most abundant immune cells in the tumor microenvironment and play a crucial role in tumor survival and development. Cold atmospheric plasma (CAP) is an emerging tool for tumor treatment that has garnered attention from scholars due to its interaction with non-tumor cells in the tumor microenvironment. Here, we used the macrophage lines THP-1 and RAW264.7, as well as the melanoma cell lines A375 and MV3, as research subjects to investigate the effect of plasma-activated liquid (PAL) on macrophage differentiation and its inhibitory effect on melanoma cell proliferation. We confirmed that the killing effect of PAL on melanoma cells was selective. Using flow cytometry and PCR, we discovered that PAL can influence macrophage differentiation. Through in vitro cell coculture, we demonstrated that PAL-treated macrophages can significantly impede tumor cell development and progression, and the effect is more potent than that of PAL directly targeting tumor cells. Furthermore, we have proposed the hypothesis that PAL promotes the differentiation of macrophages into the M1 type through the ROS/JAK2/STAT1 pathway. To test the hypothesis, we employed catalase and fludarabine to block different sites of the pathway. The results were then validated through Western Blot, qPCR and ELISA. This study illustrates that PAL therapy is an effective tumor immunotherapy and expands the scope of tumor immunotherapy. Furthermore, these findings establish a theoretical foundation for potential clinical applications of PAL.

Deciphering and overcoming Anti-PD-1 resistance in Melanoma: A comprehensive review of Mechanisms, biomarker Developments, and therapeutic strategies

Worldwide, tens of thousands of people die from melanoma each year, making it the most frequently fatal form of cutaneous cancer. Immunotherapeutic advancements, particularly with anti-PD-1 medications, have significantly enhanced treatment outcomes over recent decades. With the broad application of anti-PD-1 therapies, insights into the mechanisms of resistance have evolved. Despite the development of combination treatments and early predictive biomarkers, a comprehensive synthesis of these advancements is absent in the current literature. This review underscores the prevailing knowledge of anti-PD-1 resistance mechanisms and underscores the critical role of robust predictive biomarkers in stratifying patients for targeted combinations of anti-PD-1 and other conventional or innovative therapeutic approaches. Additionally, we offer insights that may shape future melanoma treatment strategies.

Macrophage heterogeneity and its interactions with stromal cells in tumour microenvironment

Macrophages and tumour stroma cells account for the main cellular components in the tumour microenvironment (TME). Current advancements in single-cell analysis have revolutionized our understanding of macrophage diversity and macrophage-stroma interactions. Accordingly, this review describes new insight into tumour-associated macrophage (TAM) heterogeneity in terms of tumour type, phenotype, metabolism, and spatial distribution and presents the association between these factors and TAM functional states. Meanwhile, we focus on the immunomodulatory feature of TAMs and highlight the tumour-promoting effect of macrophage-tumour stroma interactions in the immunosuppressive TME. Finally, we summarize recent studies investigating macrophage-targeted therapy and discuss their therapeutic potential in improving immunotherapy by alleviating immunosuppression.

Research progress on the role of tumor‑associated macrophages in tumor development and their use as molecular targets (Review)

The tumor microenvironment (TME) is a complex system composed mainly of tumor cells, mesenchymal cells and immune cells. Macrophages, also known as tumor‑associated macrophages (TAMs), among innate immune cells, are some of the most abundant components of the TME. They may influence tumor growth and metastasis through interactions with other cell populations in the TME and have been associated with poor prognosis in a variety of tumors. Therefore, a better understanding of the role of TAMs in the TME may provide new insight into tumor therapy. In the present review, the origin and classification of TAMs in the TME were outlined and their polarization and dual effects on tumor cells, as well as emerging strategies for cancer therapies targeting TAMs, were discussed.

The macrophage-associated prognostic gene ANXA5 promotes immunotherapy resistance in gastric cancer through angiogenesis

Gastric cancer (GC) remains a predominant form of malignant tumor globally, necessitating innovative non-surgical therapeutic approaches. This investigation aimed to delineate the expression landscape of macrophage-associated genes in GC and to evaluate their prognostic significance and influence on immunotherapeutic responsiveness. Utilizing the CellMarker2.0 database, we identified 69 immune cell markers with prognostic relevance in GC, including 12 macrophage-specific genes. A Weighted Gene Co-Expression Network Analysis (WGCNA) isolated 3,181 genes correlated with these macrophage markers. The Cancer Genome Atlas (TCGA-STAD) dataset was employed as the training set, while data from the GSE62254 served as the validation cohort. 13 genes were shortlisted through LASSO-Cox regression to formulate a prognostic model. Multivariable Cox regression substantiated that the calculated risk score serves as an imperative independent predictor of overall survival (OS). Distinct macrophage infiltration profiles, pathway associations, treatment susceptibilities, and drug sensitivities were observed between high- and low-risk groups. The preliminary validation of ANXA5 in predicting the survival rates of GC patients at 1 year, 3 years, and 5 years, as well as its expression levels were higher and role in promoting tumor angiogenesis in GC through immunohistochemistry and angiogenesis experiments. In summary, macrophage-related genes were potentially a novel crosstalk mechanism between macrophages and endothelial cells in the tumor microenvironment, and the interplay between inflammation and angiogenesis might have also offered new therapeutic targets, providing a new avenue for personalized treatment interventions.

Plasmid co-expressing siRNA-PD-1 and Endostatin carried by attenuated Salmonella enhanced the anti-melanoma effect via inhibiting the expression of PD-1 and VEGF on tumor-bearing mice

Melanoma, the most perilous form of skin cancer, is known for its inherent resistance to chemotherapy. Even with advances in tumor immunotherapy, the survival of patients with advanced or recurrent melanomas remains poor. Over time, melanoma tumor cells may produce excessive angiogenic factors, necessitating the use of combinations of angiogenesis inhibitors, including broad-spectrum options, to combat melanoma. Among these inhibitors, Endostatin is one of the most broad-spectrum and least toxic angiogenesis inhibitors. We found Endostatin significantly increased the infiltration of CD8+ T cells and reduced the infiltration of M2 tumor-associated macrophages (TAMs) in the melanoma tumor microenvironment (TME). Interestingly, we also observed high expression levels of programmed death 1 (PD-1), an essential immune checkpoint molecule associated with tumor immune evasion, within the melanoma tumor microenvironment despite the use of Endostatin. To address this issue, we investigated the effects of a plasmid expressing Endostatin and PD-1 siRNA, wherein Endostatin was overexpressed while RNA interference (RNAi) targeted PD-1. These therapeutic agents were delivered using attenuated Salmonella in melanoma-bearing mice. Our results demonstrate that pEndostatin-siRNA-PD-1 therapy exhibits optimal therapeutic efficacy against melanoma. We found that pEndostatin-siRNA-PD-1 therapy promotes the infiltration of CD8+ T cells and the expression of granzyme B in melanoma tumors. Importantly, combined inhibition of angiogenesis and PD-1 significantly suppresses melanoma tumor progression compared with the inhibition of angiogenesis or PD-1 alone. Based on these findings, our study suggests that combining PD-1 inhibition with angiogenesis inhibitors holds promise as a clinical strategy for the treatment of melanoma.

Identification and validation of M2 macrophage-related genes in endometriosis

Aims

M2 macrophage is believed to play an important role in the development of endometriosis. This study aimed to identify several key genes related to the M2 macrophage in endometriosis.

Method

Differential expressed genes between endometriosis and non-endometriosis were identified based on three microarray datasets from the Gene Expression Omnibus database. Gene modules significantly associated with M2 macrophage were identified from the weighted gene co-expression network analysis. Furthermore, by intersecting the differential expressed genes and M2 macrophage-associated module genes, M2 macrophage-related genes in endometriosis were identified. Functional analyses of the Gene Ontology and Kyoto Encyclopedia of Genes and Genomes for these genes were then performed. Following, the least absolute shrinkage and selection operator, random forest, and receiver operating characteristic curves were further conducted to identify the key M2 macrophage-related genes in endometriosis. Finally, the expressions of key genes in endometriosis, as well as their correlations with M2 macrophages were verified in an independent validation cohort.

Results

Totally, 185 M2 macrophage-related genes were identified, and they were mainly enriched in functions associated with the cell cycle, oocyte maturation, and immune response. Following machine learning algorithms, eight key genes were selected in the endometriosis: PGR, OLFM4, PIP5K1B, CCNA1, BRIP1, CADM1, PRAME, and GCNT1. The eight key genes were confirmed to be negative with M2 macrophage infiltration levels. Furthermore, the expression levels of these genes were significantly lower in the middle secretory stage while relevantly higher in the proliferative stage. The validation analysis also showed similar outcomes with the above results.

Conclusion

Eight M2 macrophage-related genes were identified as potential biomarkers of endometriosis, providing novel understanding of immune cells in the endometriosis.