• Biomolecules & Therapeutics
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• v.31 no.5
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• pp.473-483
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• 2023

Many cancers arise from sites of chronic inflammation, which creates an inflammatory microenvironment surrounding the tumor. Inflammatory substances secreted by cells in the inflammatory environment can induce the proliferation and survival of cancer cells, thereby promoting cancer metastasis and angiogenesis. Therefore, it is important to identify the role of inflammatory factors in cancer progression. This review summarizes the signaling pathways and roles of C-reactive protein (CRP) in various cancer types, including breast, liver, renal, and pancreatic cancer, and the tumor microenvironment. Mounting evidence suggests the role of CRP in breast cancer, particularly in triple-negative breast cancer (TNBC), which is typically associated with a worse prognosis. Increased CRP in the inflammatory environment contributes to enhanced invasiveness and tumor formation in TNBC cells. CRP promotes endothelial cell formation and angiogenesis and contributes to the initiation and progression of atherosclerosis. In pancreatic and kidney cancers, CRP contributes to tumor progression. In liver cancer, CRP regulates inflammatory responses and lipid metabolism. CRP modulates the activity of various signaling molecules in macrophages and monocytes present in the tumor microenvironment, contributing to tumor development, the immune response, and inflammation. In the present review, we overviewed the role of CRP signaling pathways and the association between inflammation and cancer in various types of cancer. Identifying the interactions between CRP signaling pathways and other inflammatory mediators in cancer progression is crucial for understanding the complex relationship between inflammation and cancer.

• IMMUNE NETWORK
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• v.14 no.6
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• pp.265-276
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• 2014

The interactions between B7 molecules and CD28-family receptors are crucial in the regulation of adaptive cellular immunity. In cancer, the aberrant expression of co-inhibitory B7 molecules has been attributed to reduced anti-tumor immunity and cancer immune evasion, prompting the development of cancer therapeutics that can restore T cell function. Murine tumor models have provided significant support for the targeting of multiple immune checkpoints involving CTLA-4, PD-1, ICOS, B7-H3 and B7-H4 during tumor growth, and clinical studies investigating the therapeutic effects of CTLA-4 and PD-1 blockade have shown exceptionally promising results in patients with advanced melanoma and other cancers. The expression pattern of co-inhibitory B7 ligands in the tumor microenvironment has also been largely correlated with poor patient prognosis, and recent evidence suggests that the presence of several B7 molecules may predict the responsiveness of immunotherapies that rely on pre-existing tumor-associated immune responses. While monotherapies blocking T cell co-inhibition have beneficial effects in reducing tumor burden, combinatorial immunotherapy targeting multiple immune checkpoints involved in various stages of the anti-tumor response has led to the most substantial impact on tumor reduction. In this review, we will examine the contributions of B7- and CD28-family members in the context of cancer development, and discuss the implications of current human findings in cancer immunotherapy.

• BMB Reports
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• v.53 no.10
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• pp.512-520
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• 2020

T-cell-based cancer immunotherapies, such as immune checkpoint blockers (ICBs) and chimeric antigen receptor (CAR)-T-cells, have significant anti-tumor effects against certain types of cancer, providing a new paradigm for cancer treatment. However, the activity of tumor infiltrating T-cells (TILs) can be effectively neutralized in the tumor microenvironment (TME) of most solid tumors, rich in various immunosuppressive factors and cells. Therefore, to improve the clinical outcomes of established T-cell-based immunotherapy, adjuvants that can comprehensively relieve multiple immunosuppressive mechanisms of TME are needed. In this regard, recent studies have revealed that metformin has several beneficial effects on anti-tumor immunity. In this mini-review, we understand the immunosuppressive properties of TME and how metformin comprehensively enhances anti-tumor immunity. Finally, we will discuss this old friend's potential as an adjuvant for cancer immunotherapy.

• BMB Reports
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• v.46 no.3
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• pp.131-138
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• 2013

During cancer progression, bone marrow derived myeloid cells, including immature myeloid cells and macrophages, progressively accumulate at the primary tumour site where they contribute to the establishment of a tumour promoting microenvironment. A marked infiltration of macrophages into the stromal compartment and the generation of a desmoplastic stromal reaction is a particular characteristic of pancreatic ductal adenocarcinoma (PDA) and is thought to play a key role in disease progression and its response to therapy. Tumour associated macrophages (TAMs) foster PDA tumour progression by promoting angiogenesis, metastasis, and by suppressing an anti-tumourigenic immune response. Recent work also suggests that TAMs contribute to resistance to chemotherapy and to the emergence of cancer stem-like cells. Here we will review the current understanding of the biology and the pro-tumourigenic functions of TAMs in cancer and specifically in PDA, and highlight potential therapeutic strategies to target TAMs and to improve current therapies for pancreatic cancer.

• BMB Reports
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• v.54 no.1
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• pp.31-43
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• 2021

Dendritic cells (DC), which consist of several different subsets, specialize in antigen presentation and are critical for mediating the innate and adaptive immune responses. DC subsets can be classified into conventional, plasmacytoid, and monocyte-derived DC in the tumor microenvironment, and each subset plays a different role. Because of the role of intratumoral DCs in initiating antitumor immune responses with tumor-derived antigen presentation to T cells, DCs have been targeted in the treatment of cancer. By regulating the functionality of DCs, several DC-based immunotherapies have been developed, including administration of tumor-derived antigens and DC vaccines. In addition, DCs participate in the mechanisms of classical cancer therapies, such as radiation therapy and chemotherapy. Thus, regulating DCs is also important in improving current cancer therapies. Here, we will discuss the role of each DC subset in antitumor immune responses, and the current status of DC-related cancer therapies.

• IMMUNE NETWORK
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• v.21 no.4
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• pp.31.1-31.16
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• 2021

Gastric cancer (GC) is the fourth most common cause of cancer-related death globally. The classification of advanced GC (AGC) according to molecular features has recently led to effective personalized cancer therapy for some patients. Specifically, AGC patients whose tumor cells express high levels of human epidermal growth factor receptor 2 (HER2) can now benefit from trastuzumab, a humanized monoclonal Ab that targets HER2. However, patients with HER2^negative AGC receive limited clinical benefit from this treatment. To identify potential immune therapeutic targets in HER2^negative AGC, we obtained 40 fresh AGC specimens immediately after surgical resections and subjected the CD45⁺ immune cells in the tumor microenvironment to multi-channel/multi-panel flow cytometry analysis. Here, we report that HER2 negativity associated with reduced overall survival (OS) and greater tumor infiltration with neutrophils and non-classical monocytes. The potential pro-tumoral activities of these cell types were confirmed by the fact that high expression of neutrophil or non-classical monocyte signature genes in the gastrointestinal tumors in The Cancer Genome Atlas, Genotype-Tissue Expression and Gene Expression Omnibus databases associated with worse OS on Kaplan-Meir plots relative to tumors with low expression of these signature genes. Moreover, advanced stage disease in the AGCs of our patients associated with greater tumor frequencies of neutrophils and non-classical monocytes than early stage disease. Thus, our study suggests that these 2 myeloid populations may serve as novel therapeutic targets for HER2^negative AGC.

• BMB Reports
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• v.51 no.11
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• pp.572-577
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• 2018

Recent studies showed that the PD-1/PD-L1 checkpoint blockade is a dramatic therapy for melanoma by enhancing antitumor immune activity. Currently, major strategies for the PD-1/PD-L1 blockade have mainly focused on the use of antibodies and compounds. Seeking an alternative approach, others employ endogenous proteins as blocking agents. The extracellular domain of PD-1 (ePD1) includes the binding site with PD-L1. Accordingly, we constructed a PD-1-based recombinantly tailored fusion protein (dFv-ePD1) that consists of bivalent variable fragments (dFv) of an MMP-2/9-targeted antibody and ePD1. The melanoma-binding intensity and antitumor activity were also investigated. We found the intense and selective binding capability of the protein dFv-ePD1 to human melanoma specimens was confirmed by a tissue microarray. In addition, dFv-ePD1 significantly suppressed the migration and invasion of mouse melanoma B16-F1 cells, and displayed cytotoxicity to cancer cells in vitro. Notably, dFv-ePD1 significantly inhibited the growth of mouse melanoma B16-F1 tumor cells in mice and in vivo fluorescence imaging showed that dFv-ePD was gradually accumulated into the B16-F1 tumor. Also the B16-F1 tumor fluorescence intensity at the tumor site was stronger than that of dFv. This study indicates that the recombinant protein dFv-ePD1 has an intensive melanoma-binding capability and exerts potent therapeutic efficacy against melanoma. The novel format of the PD-L1-blocked agent may play an active role in antitumor immunotherapy.

• IMMUNE NETWORK
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• v.20 no.1
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• pp.11.1-11.14
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• 2020

Most patients with hepatocellular carcinoma (HCC) are diagnosed at an advanced stage of disease. Until recently, systemic treatment options that showed survival benefits in HCC have been limited to tyrosine kinase inhibitors, antibodies targeting oncogenic signaling pathways or VEGF receptors. The HCC tumor microenvironment is characterized by a dysfunction of the immune system through multiple mechanisms, including accumulation of various immunosuppressive factors, recruitment of regulatory T cells and myeloid-derived suppressor cells, and induction of T cell exhaustion accompanied with the interaction between immune checkpoint ligands and receptors. Immune checkpoint inhibitors (ICIs) have been interfered this interaction and have altered therapeutic landscape of multiple cancer types including HCC. In this review, we discuss the use of anti-PD-1, anti-PD-L1, and anti-CTLA-4 antibodies in the treatment of advanced HCC. However, ICIs as a single agent do not benefit a significant portion of patients. Therefore, various clinical trials are exploring possible synergistic effects of combinations of different ICIs (anti-PD-1/PD-L1 and anti-CTLA-4 antibodies) or ICIs and target agents. Combinations of ICIs with locoregional therapies may also improve therapeutic responses.

• BMB Reports
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• v.54 no.8
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• pp.431-436
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• 2021

In recent years, restoring anti-tumor immunity has garnered a growing interest in cancer treatment. As potential therapeutics, immune checkpoint inhibitors have demonstrated benefits in many clinical studies. Although various methods have been applied to suppress immune checkpoints to boost anti-tumor immunity, including the use of immune checkpoint inhibitors, there are still unmet clinical needs to improve the response rate of cancer treatment. Here, we show that acetate can suppress the expression of poliovirus receptor (PVR/CD155), a ligand for immune checkpoint, in colon cancer cells. We demonstrated that acetate treatment could enhance effector responses of CD8⁺ T cells by decreasing the expression of PVR/CD155 in cancer cells. We also found that acetate could reduce the expression of PVR/CD155 by deactivating the PI3K/AKT pathway. These results demonstrate that acetate-mediated expression of PVR/CD155 in cancer cells might potentiate the anti-tumor immunity in the microenvironment of cancer. Our findings indicate that maintaining particular acetate concentrations could be a complementary strategy in current cancer treatment.

• Biomolecules & Therapeutics
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• v.32 no.3
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• pp.281-290
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• 2024

Pancreatic ductal adenocarcinoma (PDAC) has a poor prognosis owing to its desmoplastic stroma. Therefore, therapeutic strategies targeting this tumor stroma should be developed. In this study, we describe the heterogeneity of cancer-associated fibroblasts (CAFs) and their diverse roles in the progression, immune evasion, and resistance to treatment of PDAC. We subclassified the spatial distribution and functional activity of CAFs to highlight their effects on prognosis and drug delivery. Extracellular matrix components such as collagen and hyaluronan are described for their roles in tumor behavior and treatment outcomes, implying their potential as therapeutic targets. We also discussed the roles of extracellular matrix (ECM) including matrix metalloproteinases and tissue inhibitors in PDAC progression. Finally, we explored the role of the adaptive and innate immune systems in shaping the PDAC microenvironment and potential therapeutic strategies, with a focus on immune cell subsets, cytokines, and immunosuppressive mechanisms. These insights provide a comprehensive understanding of PDAC and pave the way for the development of prognostic markers and therapeutic interventions.