Pentraxin-3 inhibits milky spots metastasis of gastric cancer by inhibiting M2 macrophage polarization

Unveiling the oncogenic role of CLDN11-secreting fibroblasts in gastric cancer peritoneal metastasis through single-cell sequencing and experimental approaches

BACKGROUND

Fibroblasts are necessary to the progression of cancer. However, the role of fibroblasts in peritoneal metastasis (PM) of gastric cancer (GC) remains elusive. In this study, we would explore the role of fibroblasts mediated cell interaction in PM of GC.

METHODS

Single-cell sequencing data from public database GSE183904 was used to explore the specific fibroblast cluster. Fibroblasts were extracted from PM and GC tissues. The expression level of CXCR7 was verified by western blot, immunohistochemistry. The role of CLDN11 was investigate through in vitro and in vivo study. Multiple immunohistochemistry was used to characterize the tumor microenvironment.

RESULTS

CXCR7-positive fibroblasts were significantly enriched in PM of GC. CXCR7 could promote the expression of CLDN11 through activation of the AKT pathway in fibroblasts. Fibroblasts promote the GC proliferation and peritoneal metastasis by secreting CLDN11 in vitro and in vivo. Furthermore, it was revealed that CXCR7-positive fibroblasts were significantly associated with M2-type macrophages infiltration in tissues.

CONCLUSION

CXCR7-positive fibroblasts play an essential role in PM of GC via CLDN11. Therapy targeting CXCR7-positive fibroblasts or CLDN11 may be helpful in the treatment of GC with PM.

Inactivation of pentraxin 3 suppresses M2-like macrophage activity and immunosuppression in colon cancer

BACKGROUND

The tumor microenvironment is characterized by inflammation-like and immunosuppression situations. Although cancer-associated fibroblasts (CAFs) are among the major stromal cell types in various solid cancers, including colon cancer, the interactions between CAFs and immune cells remains largely uncharacterized. Pentraxin 3 (PTX3) is responsive to proinflammatory cytokines and modulates immunity and tissue remodeling, but its involvement in tumor progression appears to be context-dependent and is unclear.

METHODS

Open-access databases were utilized to examine the association of PTX3 expression and the fibroblast signature in colon cancer. Loss-of-function assays, including studies in tamoxifen-induced Ptx3 knockout mice and treatment with an anti-PTX3 neutralizing antibody (WHC-001), were conducted to assess the involvement of PTX3 in colon cancer progression as well as its immunosuppressive effect. Finally, bioinformatic analyses and in vitro assays were performed to reveal the downstream effectors and decipher the involvement of the CREB1/CEBPB axis in response to PTX3 and PTX3-induced promotion of M2 macrophage polarization.

RESULTS

Clinically, higher PTX3 expression was positively correlated with fibroblasts and inflammatory response signatures and associated with a poor survival outcome in colon cancer patients. Blockade of PTX3 significantly reduced stromal cell-mediated tumor development. The decrease of the M2 macrophage population and an increase of the cytotoxic CD8+ T-cell population were observed following PTX3 inactivation in allografted colon tumors. We further revealed that activation of cyclic AMP-responsive element-binding protein 1 (CREB1) mediated the PTX3-induced promotion of M2 macrophage polarization.

CONCLUSIONS

PTX3 contributes to stromal cell-mediated protumor immunity by increasing M2-like macrophage polarization, and inhibition of PTX3 with WHC-001 is a potential therapeutic strategy for colon cancer.

The Role of Pentraxin 3 in Gastrointestinal Cancers

Gastrointestinal cancers have become a huge problem worldwide as the number of new cases continues to increase. Due to the growing need to explore new biomarkers and therapeutic targets for the detection and treatment of cancerous lesions, we sought to elucidate the role of Pentraxin-3 in the progression of cancerous lesions, as it is involved in the process of angiogenesis and inflammation. Statistically significant changes in the concentration of this parameter have emerged in many gastrointestinal cancer patients. Moreover, it is related to the advancement of cancer, as well as processes leading to the development of those changes. In the case of studies concerning tissue material, both increased and decreased tissue expression of the tested parameter were observed and were dependent on the type of cancer. In the case of cell lines, both human and animal, a significant increase in Pentraxin 3 gene expression was observed, which confirmed the changes observed at the protein level. In conclusion, it can be assumed that PTX3, both at the level of gene expression and protein concentrations, is highly useful in the detection of gastrointestinal cancers, and its use as a biomarker and/or therapeutic target may be useful in the future.

Role of long pentraxin PTX3 in cancer

Cancer has become a leading cause of death and disease burden worldwide, closely related to rapid socioeconomic development. However, the fundamental reason is the lack of comprehensive understanding of the mechanism of cancer, accurate identification of preclinical cancer, and effective treatment of the disease. Therefore, it is particularly urgent to study specific mechanisms of cancer and develop effective prediction and treatment methods. Long Pentraxin PTX3 is a soluble pattern recognition molecule produced by various cells in inflammatory sites, which plays a role as a promoter or suppressor of cancer in multiple tumors through participating in innate immune response, neovascularization, energy metabolism, invasion, and metastasis mechanisms. Based on this, this article mainly reviews the role of PTX3 in various cancers.

Research progress on the immune microenvironment and immunotherapy in gastric cancer

The tumor microenvironment, particularly the immune microenvironment, plays an indispensable role in the malignant progression and metastasis of gastric cancer (GC). As our understanding of the GC microenvironment continues to evolve, we are gaining deeper insights into the biological mechanisms at the single-cell level. This, in turn, has offered fresh perspectives on GC therapy. Encouragingly, there are various monotherapy and combination therapies in use, such as immune checkpoint inhibitors, adoptive cell transfer therapy, chimeric antigen receptor T cell therapy, antibody-drug conjugates, and cancer vaccines. In this paper, we review the current research progress regarding the GC microenvironment and summarize promising immunotherapy research and targeted therapies.

The pentraxin family in autoimmune disease

The pentraxins represent a family of multifunctional proteins composed of long and short pentamers. The latter includes serum amyloid P component (SAP) and C-reactive protein (CRP) whereas the former includes neuronal PTX1 and PTX2 (NPTX1 and NPTX2, respectively), PTX3 and PTX4. These serve as a bridge between adaptive immunity and innate immunity and a link between inflammation and immunity. Similarities and differences between long and short pentamers are examined and their roles in autoimmune disease are discussed. Increased CRP and PTX3 could indicate the activity of rheumatoid arthritis, systemic lupus erythematosus or other autoimmune diseases. Mechanistically, CRP and PTX3 may predict target organ injury, regulate bone metabolic immunity and maintain homeostasis as well as participate in vascular endothelial remodeling. Interestingly, PTX3 is pleiotropic, being involved in inflammation and tissue repair. Given the therapeutic potential of PTX3 and CRP, targeting these factors to exert a beneficial effect is the focus of research efforts. Unfortunately, studies on NPTX1, NPTX2, PTX4 and SAP are scarce and more research is clearly needed to elaborate their potential roles in autoimmune disease.

CAP2 promotes gastric cancer metastasis by mediating the interaction between tumor cells and tumor-associated macrophages

The metastasis of cancer cells is the main cause of death in patients with gastric cancer (GC). Mounting evidence has demonstrated the vital importance of tumor-associated macrophages in promoting tumor invasion and metastasis; however, the interaction between tumor cells and macrophages in GC is largely unknown. In this study, we demonstrated that cyclase-associated protein 2 (CAP2) was upregulated in GC, especially in cases with lymph node metastasis, and was correlated with a poorer prognosis. The transcription factor JUN directly bound to the promoter region of CAP2 and activated CAP2 transcription. The N-terminal domain of CAP2 bound to the WD5 to WD7 domains of receptor for activated C kinase 1 (RACK1) and induced M2 macrophage polarization by activating the SRC/focal adhesion kinase (FAK)/ERK signaling pathway, which resulted in IL-4 and IL-10 secretion. Polarized M2 macrophages induced premetastatic niche formation and promoted GC metastasis by secreting TGFB1, which created a TGFB1/JUN/CAP2 positive-feedback loop to activate CAP2 expression continuously. Furthermore, we identified salvianolic acid B as an inhibitor of CAP2, which effectively inhibited GC cell invasion capabilities by suppressing the SRC/FAK/ERK signaling pathway. Our data suggest that CAP2, a key molecule mediating the interaction between GC cells and tumor-associated macrophages, may be a promising therapeutic target for suppressing tumor metastasis in GC.

Tumour-associated macrophages in gastric cancer: From function and mechanism to application

BACKGROUND

Gastric cancer (GC) is a malignant tumour, with high morbidity and mortality rates worldwide. The occurrence and development of GC is a complex process involving genetic changes in tumour cells and the influence of the surrounding tumour microenvironment (TME). Accumulative evidence shows that tumour-associated macrophages (TAMs) play a vital role in GC, acting as plentiful and active infiltrating inflammatory cells in the TME.

MAIN BODY

In this review, the different functions and mechanisms of TAMs in GC progression, including the conversion of phenotypic subtypes; promotion of tumour proliferation, invasion and migration; induction of chemoresistance; promotion of angiogenesis; modulation of immunosuppression; reprogramming of metabolism; and interaction with the microbial community are summarised. Although the role of TAMs in GC remains controversial in clinical settings, clarifying their significance in the treatment selection and prognostic prediction of GC could support optimising TAM-centred clinicaltherapy.

CONCLUSION

In summary, we reviewed the the phenotypic polarisation, function and molecular mechanism of TAMs and their potential applications in the treatment selection and prognostic prediction of GC.

Glycyrrhetinic acid suppresses breast cancer metastasis by inhibiting M2-like macrophage polarization via activating JNK1/2 signaling

BACKGROUND

Breast cancer metastasis is leading cause of cancer death among women worldwide. Tumor-associated macrophages (TAMs) have been considered as potential targets for treating breast cancer metastasis because they promote tumor growth and development. Glycyrrhetinic acid (GA) is one of the most important phytochemicals of licorice which has shown promising anti-cancer efficacies in pre-clinical trials. However, the regulatory effect of GA on the polarization of TAMs remains elusive.

PURPOSE

To investigate the role of GA in regulating the polarization of M2 macrophages and inhibiting breast cancer metastasis, and to further explore its underlying mechanisms of action.

STUDY DESIGN

IL-4 / IL-13-treated RAW 264.7 and THP-1 cells were used as the M2-polarized macrophages in vitro. A 4T1 mouse breast cancer model and the tail vein breast cancer metastasis model were applied to study the effect of GA on breast cancer growth and metastasis in vivo.

RESULTS

In vitro studies showed that GA significantly inhibited IL-4 / IL 13-induced M2-like polarization in RAW 264.7 and THP-1 macrophages without affecting M1-like polarization. GA strongly decreased the expression of M2 macrophage markers CD206 and Arg-1, and reduced the levels of the pro-angiogenic molecules VEGF, MMP9, MMP2 and IL-10 in M2 macrophages. GA also increased the phosphorylation of JNK1/2 in M2 macrophages. Moreover, GA significantly suppressed M2 macrophage-induced cell proliferation and migration in 4T1 cancer cells and HUVECs. Interestingly, the inhibitory effects of GA on M2 macrophages were abolished by a JNK inhibitor. Animal studies showed that GA significantly suppressed tumor growth, angiogenesis, and lung metastasis in BALB/c mice bearing breast tumor. In tumor tissues, GA reduced the number of M2 macrophages but elevated the proportion of M1 macrophages, accompanied by activation of JNK signaling. Similar results were found in the tail vein breast cancer metastasis model.

CONCLUSION

This study demonstrated for the first time that GA could effectively suppress breast cancer growth and metastasis by inhibiting macrophage M2 polarization via activating JNK1/2 signaling. These findings indicate that GA could be served as the lead compound for the future development of anti-breast cancer drug.

The Potential Use of Exosomes in Anti-Cancer Effect Induced by Polarized Macrophages

The rapid development of aberrant cells outgrowing their normal bounds, which can subsequently infect other body parts and spread to other organs-a process known as metastasis-is one of the significant characteristics of cancer. The main reason why cancer patients die is because of widespread metastases. This abnormal cell proliferation varies in cancers of over a hundred types, and their response to treatment can vary substantially. Several anti-cancer drugs have been discovered to treat various tumors, yet they still have harmful side-effects. Finding novel, highly efficient targeted therapies based on modifications in the molecular biology of tumor cells is essential to reduce the indiscriminate destruction of healthy cells. Exosomes, an extracellular vesicle, are promising as a drug carrier for cancer therapy due to their good tolerance in the body. In addition, the tumor microenvironment is a potential target to regulate in cancer treatment. Therefore, macrophages are polarized toward M1 and M2 phenotypes, which are involved in cancer proliferation and are malignant. It is evident from recent studies that controlled macrophage polarization might contribute to cancer treatment, by the direct way of using miRNA. This review provides an insight into the potential use of exosomes to develop an 'indirect', more natural, and harmless cancer treatment through regulating macrophage polarization.

Insights into the Relationship between Pentraxin-3 and Cancer

Although cancer can be cured if detected early and treated effectively, it is still a leading cause of death worldwide. Tumor development can be limited by an appropiate immune response, but it can be promoted by chronic extensive inflammation through metabolic dysregulation and angiogenesis. In the past decade, numerous efforts have been made in order to identify novel candidates with predictive values in cancer diagnostics. In line with this, researchers have investigated the involvement of pentraxin-3 (PTX-3) in cellular proliferation and immune escape in various types of cancers, although it has not been clearly elucidated. PTX-3 is a member of the long pentraxin subfamily which plays an important role in regulating inflammation, innate immunity response, angiogenesis, and tissue remodeling. Increased synthesis of inflammatory biomarkers and activation of different cellular mechanisms can induce PTX-3 expression in various types of cells (neutrophils, monocytes, lymphocytes, myeloid dendritic cells, fibroblasts, and epithelial cells). PTX-3 has both pro- and anti-tumor functions, thus dual functions in oncogenesis. This review elucidates the potential usefulness of PTX-3 as a serum biomarker in cancer. While future investigations are needed, PTX-3 is emerging as a promising tool for cancer's diagnosis and prognosis, and also treatment monitoring.

Tumor microenvironment-mediated immune tolerance in development and treatment of gastric cancer

Tumor microenvironment is the general term for all non-cancer components and their metabolites in tumor tissue. These components include the extracellular matrix, fibroblasts, immune cells, and endothelial cells. In the early stages of tumors, the tumor microenvironment has a tumor suppressor function. As the tumor progresses, tumor immune tolerance is induced under the action of various factors, such that the tumor suppressor microenvironment is continuously transformed into a tumor-promoting microenvironment, which promotes tumor immune escape. Eventually, tumor cells manifest the characteristics of malignant proliferation, invasion, metastasis, and drug resistance. In recent years, stress effects of the extracellular matrix, metabolic and phenotypic changes of innate immune cells (such as neutrophils, mast cells), and adaptive immune cells in the tumor microenvironment have been revealed to mediate the emerging mechanisms of immune tolerance, providing us with a large number of emerging therapeutic targets to relieve tumor immune tolerance. Gastric cancer is one of the most common digestive tract malignancies worldwide, whose mortality rate remains high. According to latest guidelines, the first-line chemotherapy of advanced gastric cancer is the traditional platinum and fluorouracil therapy, while immunotherapy for gastric cancer is extremely limited, including only Human epidermal growth factor receptor 2 (HER-2) and programmed death ligand 1 (PD-L1) targeted drugs, whose benefits are limited. Clinical experiments confirmed that cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), vascular endothelial growth factor receptor (VEGFR) and other targeted drugs alone or in combination with other drugs have limited efficacy in patients with advanced gastric cancer, far less than in lung cancer, colon cancer, and other tumors. The failure of immunotherapy is mainly related to the induction of immune tolerance in the tumor microenvironment of gastric cancer. Therefore, solving the immune tolerance of tumors is key to the success of gastric cancer immunotherapy. In this study, we summarize the latest mechanisms of various components of the tumor microenvironment in gastric cancer for inducing immune tolerance and promoting the formation of the malignant phenotype of gastric cancer, as well as the research progress of targeting the tumor microenvironment to overcome immune tolerance in the treatment of gastric cancer.