Modulating mammary tumor growth, metastasis and immunosuppression by siRNA-induced MIF reduction in tumor microenvironment

Mycobiome: an underexplored kingdom in cancer

SUMMARYThe human microbiome, including bacteria, fungi, archaea, and viruses, is intimately linked to both health and disease. The relationship between bacteria and disease has received much attention and intensive investigation, while that of the fungal microbiome, also known as mycobiome, has lagged far behind bacteria. There is growing evidence showing mycobiome dysbiosis in cancer patients, and certain cancer-specific fungi may contribute to cancer progression by interacting with both host and bacteria. It was also demonstrated that the role of fungi-derived products in cancer should also not be underestimated. Therefore, investigating how fungal pathogenesis contributes to the onset and spread of cancer would yield crucial information for cancer diagnosis, prevention, and anti-cancer therapy.

Non-Coding RNAs in Breast Cancer: Diagnostic and Therapeutic Implications

Breast cancer (BC) is one of the most prevalent forms of cancer globally, and has recently become the leading cause of cancer-related mortality in women. BC is a heterogeneous disease comprising various histopathological and molecular subtypes with differing levels of malignancy, and each patient has an individual prognosis. Etiology and pathogenesis are complex and involve a considerable number of genetic alterations and dozens of alterations in non-coding RNA expression. Non-coding RNAs are part of an abundant family of single-stranded RNA molecules acting as key regulators in DNA replication, mRNA processing and translation, cell differentiation, growth, and overall genomic stability. In the context of breast cancer, non-coding RNAs are involved in cell cycle control and tumor cell migration and invasion, as well as treatment resistance. Alterations in non-coding RNA expression may contribute to the development and progression of breast cancer, making them promising biomarkers and targets for novel therapeutic approaches. Currently, the use of non-coding RNAs has not yet been applied to routine practice; however, their potential has been very well studied. The present review is a literature overview of current knowledge and its objective is to delineate the function of diverse classes of non-coding RNAs in breast cancer, with a particular emphasis on their potential utility as diagnostic and prognostic markers or as therapeutic targets and tools.

Unleashing nanotechnology to redefine tumor-associated macrophage dynamics and non-coding RNA crosstalk in breast cancer

Breast cancer is a significant global health issue. Tumor-associated macrophages (TAMs) are crucial in influencing the tumor microenvironment and the progression of the disease. TAMs exhibit remarkable plasticity in adopting distinct phenotypes ranging from pro-inflammatory and anti-tumorigenic (M1-like) to immunosuppressive and tumor-promoting (M2-like). This review elucidates the multifaceted roles of TAMs in driving breast tumor growth, angiogenesis, invasion, and metastatic dissemination. Significantly, it highlights the intricate crosstalk between TAMs and non-coding RNAs (ncRNAs), including microRNAs, long noncoding RNAs, and circular RNAs, as a crucial regulatory mechanism modulating TAM polarization and functional dynamics that present potential therapeutic targets. Nanotechnology-based strategies are explored as a promising approach to reprogramming TAMs toward an anti-tumor phenotype. Various nanoparticle delivery systems have shown potential for modulating TAM polarization and inhibiting tumor-promoting effects. Notably, nanoparticles can deliver ncRNA therapeutics to TAMs, offering unique opportunities to modulate their polarization and activity.

Novel insights into immune cells modulation of tumor resistance

Tumor resistance poses a significant challenge to effective cancer treatment, making it imperative to explore new therapeutic strategies. Recent studies have highlighted the profound involvement of immune cells in the development of tumor resistance. Within the tumor microenvironment, macrophages undergo polarization into the M2 phenotype, thus promoting the emergence of drug-resistant tumors. Neutrophils contribute to tumor resistance by forming extracellular traps. While T cells and natural killer (NK) cells exert their impact through direct cytotoxicity against tumor cells. Additionally, dendritic cells (DCs) have been implicated in preventing tumor drug resistance by stimulating T cell activation. In this review, we provide a comprehensive summary of the current knowledge regarding immune cell-mediated modulation of tumor resistance at the molecular level, with a particular focus on macrophages, neutrophils, DCs, T cells, and NK cells. The targeting of immune cell modulation exhibits considerable potential for addressing drug resistance, and an in-depth understanding of the molecular interactions between immune cells and tumor cells holds promise for the development of innovative therapies. Furthermore, we explore the clinical implications of these immune cells in the treatment of drug-resistant tumors. This review emphasizes the exploration of novel approaches that harness the functional capabilities of immune cells to effectively overcome drug-resistant tumors.

Therapeutic Opportunities in Breast Cancer by Targeting Macrophage Migration Inhibitory Factor as a Pleiotropic Cytokine

As a heterogeneous disease, breast cancer (BC) has been characterized by the uncontrolled proliferation of mammary epithelial cells. The tumor microenvironment (TME) also contains inflammatory cells, fibroblasts, the extracellular matrix (ECM), and soluble factors that all promote BC progression. In this sense, the macrophage migration inhibitory factor (MIF), a pleiotropic pro-inflammatory cytokine and an upstream regulator of the immune response, enhances breast tumorigenesis through escalating cancer cell proliferation, survival, angiogenesis, invasion, metastasis, and stemness, which then brings tumorigenic effects by activating key oncogenic signaling pathways and inducing immunosuppression. Against this background, this review was to summarize the current understanding of the MIF pathogenic mechanisms in cancer, particularly BC, and address the central role of this immunoregulatory cytokine in signaling pathways and breast tumorigenesis. Furthermore, different inhibitors, such as small molecules as well as antibodies (Abs) or small interfering RNA (siRNA) and their anti-tumor effects in BC studies were examined. Small molecules and other therapy target MIF. Considering MIF as a promising therapeutic target, further clinical evaluation of MIF-targeted agents in patients with BC was warranted.

Breast Cancer Treatment Strategies Targeting the Tumor Microenvironment: How to Convert "Cold" Tumors to "Hot" Tumors

Breast cancer characterized as "cold tumors" exhibit low levels of immune cell infiltration, which limits the efficacy of conventional immunotherapy. Recent studies have focused on strategies using nanotechnology combined with tumor microenvironment modulation to transform "cold tumors" into "hot tumors". This approach involves the use of functionalized nanoparticles that target and modify the tumor microenvironment to promote the infiltration and activation of antitumor immune cells. By delivering immune activators or blocking immunosuppressive signals, these nanoparticles activate otherwise dormant immune responses, enhancing tumor immunogenicity and the therapeutic response. These strategies not only promise to increase the response rate of breast cancer patients to existing immunotherapies but also may pave new therapeutic avenues, providing a new direction for the immunotherapy of breast cancer.

The Multifunction Role of Tumor-Associated Mesenchymal Stem Cells and Their Interaction with Immune Cells in Breast Cancer

Mesenchymal stem cells (MSCs) are a heterogeneous group of progenitor cells that play a multifunctional role including tissue regeneration, self-renewal properties, and differentiate into cells of mesodermal lineage such as adipocytes, osteoblasts, and chondrocytes. MSCs come into contact with tumor microenvironment (TME) and differentiate into tumor-associated MSCs (TA-MSCs). Various substances such as chemokines, cytokines, growth factors, and others are released by tumor cells to recruit MSCs. TA-MSCs induced epithelial-mesenchymal transition (EMT) program which mediates tumor growth progression, migration, and invasion. Role of MSCs in the tumor progression, stemness, malignancy, and treatment resistance in the breast cancer TME. Immunomodulation by MSCs is mediated by a combination of cell contact-dependent mechanisms and soluble substances. Monocytes/macrophages, dendritic cells, T cells, B cells, and NK cells all show signs of MSCs' immunomodulatory capability. In a complicated interplay initiated by MSCs, anti-inflammatory monocytes/macrophages and regulatory T cells (Tregs) play a key role, as they unveil their full immunomodulatory potential. MSC- secreted cytokines are commonly blamed for the interaction between MSCs, monocytes, and Tregs. Here, we review the current knowledge of cellular and molecular mechanisms involved in MSC-mediated immunomodulation and focus on the role MSCs play in breast cancer progression and its TME.Abbreviation MSC: Mesenchymal Stem Cells; TME: Tumor Microenvironment; TAMS; Tumour-associated Macrophages; ECM: Extracellular matrix; CAFs: Cancer-associated Fibroblasts; CFUs: Colony-forming unit Fibroblasts; Tregs: T regulatory cells; Bregs; Regulatory B cells; IFN-γ: Interferon-gamma; TNF-α: Tumour Necrosis Factor-alpha; IL: Interleukin; TGF-β: transforming growth factorβ; PGE2: Prostaglandin E2; CXCR: Chemokine Receptor; Blimp-1; B lymphocyte-induced maturation protein-1; CCL: Chemokine motif ligand; EMT: Epithelial-mesenchymal transition.

Single-cell RNA sequencing identifies a novel proliferation cell type affecting clinical outcome of pancreatic ductal adenocarcinoma

Background

Pancreatic ductal adenocarcinoma (PDAC) is an extremely deadly neoplasm, with only a 5-year survival rate of around 9%. The tumor and its microenvironment are highly heterogeneous, and it is still unknown which cell types influence patient outcomes.

Methods

We used single-cell RNA sequencing (scRNA-seq) and spatial transcriptome (ST) to identify differences in cell types. We then applied the scRNA-seq data to decompose the cell types in bulk RNA sequencing (bulk RNA-seq) data from the Cancer Genome Atlas (TCGA) cohort. We employed unbiased machine learning integration algorithms to develop a prognosis signature based on cell type makers. Lastly, we verified the differential expression of the key gene LY6D using immunohistochemistry and qRT-PCR.

Results

In this study, we identified a novel cell type with high proliferative capacity, Prol, enriched with cell cycle and mitosis genes. We observed that the proportion of Prol cells was significantly increased in PDAC, and Prol cells were associated with reduced overall survival (OS) and progression-free survival (PFS). Additionally, the marker genes of Prol cell type, identified from scRNA-seq data, were upregulated and associated with poor prognosis in the bulk RNA-seq data. We further confirmed that mutant KRAS and TP53 were associated with an increased abundance of Prol cells and that these cells were associated with an immunosuppressive and cold tumor microenvironment in PDAC. ST determined the spatial location of Prol cells. Additionally, patients with a lower proportion of Prol cells in PDAC may benefit more from immunotherapy and gemcitabine treatment. Furthermore, we employed unbiased machine learning integration algorithms to develop a Prol signature that can precisely quantify the abundance of Prol cells and accurately predict prognosis. Finally, we confirmed that the LY6D protein and mRNA expression were markedly higher in pancreatic cancer than in normal pancreatic tissue.

Conclusions

In summary, by integrating bulk RNA-seq and scRNA-seq, we identified a novel proliferative cell type, Prol, which influences the OS and PFS of PDAC patients.

Antitumor therapy for breast cancer: Focus on tumor-associated macrophages and nanosized drug delivery systems

BACKGROUND

In breast cancer (BC), tumor-associated macrophages (TAMs) are an important component of the tumor microenvironment and are closely related to poor prognosis. A growing number of studies have focused on the role of TAMs in BC progression and therapeutic strategies targeting TAMs. As an emerging treatment, the application of nanosized drug delivery systems (NDDSs) in the treatment of BC by targeting TAMs has attracted much attention.

AIMS

This review is to summarize the characteristics and treatment strategies targeting TAMs in BC and to clarify the applications of NDDSs targeting TAMs in the treatment of BC by targeting TAMs.

MATERIALS & METHODS

The existing results related to characteristics of TAMs in BC, BC treatment strategies by targeting TAMs, and the applications of NDDSs in these strategies are described. Through analyzing these results, the advantages and disadvantages of the treatment strategies using NDDSs are discussed, which could provide advices on designing NDDSs for BC treatment.

RESULTS

TAMs are one of the most prominent noncancer cell types in BC. TAMs not only promote angiogenesis, tumor growth and metastasis but also lead to therapeutic resistance and immunosuppression. Mainly four strategies have been used to target TAMs for BC therapy, which include depleting macrophages, blocking recruitment, reprogramming to attain an anti-tumor phenotype, and increasing phagocytosis. Since NDDSs can efficiently deliver drugs to TAMs with low toxicity, they are promising approaches for targeting TAMs in tumor therapy. NDDSs with various structures can deliver immunotherapeutic agents and nucleic acid therapeutics to TAMs. In addition, NDDSs can realize combination therapies.

DISCUSSION

TAMs play a critical role in the progression of BC. An increasing number of strategies have been proposed to regulate TAMs. Compared with free drugs, NDDSs targeting TAMs improve drug concentration, reduce toxicity and realize combination therapies. However, in order to achieve better therapeutic efficacy, there are still some disadvantages that need to be considered in the design of NDDSs.

CONCLUSION

TAMs play an important role in the progression of BC, and targeting TAMs is a promising strategy for BC therapy. In particular, NDDSs targeting TAMs have unique advantages and are potential treatments for BC.

The Innate Immune Microenvironment in Metastatic Breast Cancer

The immune system plays a fundamental role in neoplastic disease. In the era of immunotherapy, the adaptive immune response has been in the spotlight whereas the role of innate immunity in cancer development and progression is less known. The tumor microenvironment influences the terminal differentiation of innate immune cells, which can explicate their pro-tumor or anti-tumor effect. Different cells are able to recognize and eliminate no self and tumor cells: macrophages, natural killer cells, monocytes, dendritic cells, and neutrophils are, together with the elements of the complement system, the principal players of innate immunity in cancer development and evolution. Metastatic breast cancer is a heterogeneous disease from the stromal, immune, and biological point of view and requires deepened exploration to understand different patient outcomes. In this review, we summarize the evidence about the role of innate immunity in breast cancer metastatic sites and the potential targets for optimizing the innate response as a novel treatment opportunity.

Recent Advances in PROTACs for Drug Targeted Protein Research

Proteolysis-targeting chimera (PROTAC) is a heterobifunctional molecule. Typically, PROTAC consists of two terminals which are the ligand of the protein of interest (POI) and the specific ligand of E3 ubiquitin ligase, respectively, via a suitable linker. PROTAC degradation of the target protein is performed through the ubiquitin–proteasome system (UPS). The general process is that PROTAC binds to the target protein and E3 ligase to form a ternary complex and label the target protein with ubiquitination. The ubiquitinated protein is recognized and degraded by the proteasome in the cell. At present, PROTAC, as a new type of drug, has been developed to degrade a variety of cancer target proteins and other disease target proteins, and has shown good curative effects on a variety of diseases. For example, PROTACs targeting AR, BR, BTK, Tau, IRAK4, and other proteins have shown unprecedented clinical efficacy in cancers, neurodegenerative diseases, inflammations, and other fields. Recently, PROTAC has entered a phase of rapid development, opening a new field for biomedical research and development. This paper reviews the various fields of targeted protein degradation by PROTAC in recent years and summarizes and prospects the hot targets and indications of PROTAC.

DNA minicircles as novel STAT3 decoy oligodeoxynucleotides endowed with anticancer activity in triple-negative breast cancer

Decoy technology is a versatile and specific DNA oligonucleotide-based targeting strategy of pathogenic transcription factors (TFs). Chemical modifications of linear decoy oligonucleotides have been made to decrease nuclease sensitivity because of the presence of free ends but at the cost of new limitations that affect their use as therapeutic drugs. Although a short DNA minicircle is a phosphodiester nucleic acid without free ends, its potential therapeutic activity as a TF decoy oligonucleotide has not yet been investigated. Here we describe the in vitro and in vivo activity of formulated 95-bp minicircles bearing one or several STAT3 binding sequences in triple-negative breast cancer (TNBC). Minicircles bearing one STAT3 binding site interacted specifically with the active form of STAT3 and inhibited proliferation, induced apoptosis, slowed down cell cycle progression, and decreased STAT3 target gene expression in human and murine TNBC cells. Intratumoral injection of STAT3 minicircles inhibited tumor growth and metastasis in a murine model of TNBC. Increasing the number of STAT3 binding sites resulted in improved anticancer activity, opening the way for a TF multitargeting strategy. Our data provide the first demonstration of minicircles acting as STAT3 decoys and show that they could be an effective therapeutic drug for TNBC treatment.

TA-MSCs, TA-MSCs-EVs, MIF: their crosstalk in immunosuppressive tumor microenvironment

As an important component of the immunosuppressive tumor microenvironment (TME), it has been established that mesenchymal stem cells (MSCs) promote the progression of tumor cells. MSCs can directly promote the proliferation, migration, and invasion of tumor cells via cytokines and chemokines, as well as promote tumor progression by regulating the functions of anti-tumor immune and immunosuppressive cells. MSCs-derived extracellular vesicles (MSCs-EVs) contain part of the plasma membrane and signaling factors from MSCs; therefore, they display similar effects on tumors in the immunosuppressive TME. The tumor-promoting role of macrophage migration inhibitory factor (MIF) in the immunosuppressive TME has also been revealed. Interestingly, MIF exerts similar effects to those of MSCs in the immunosuppressive TME. In this review, we summarized the main effects and related mechanisms of tumor-associated MSCs (TA-MSCs), TA-MSCs-EVs, and MIF on tumors, and described their relationships. On this basis, we hypothesized that TA-MSCs-EVs, the MIF axis, and TA-MSCs form a positive feedback loop with tumor cells, influencing the occurrence and development of tumors. The functions of these three factors in the TME may undergo dynamic changes with tumor growth and continuously affect tumor development. This provides a new idea for the targeted treatment of tumors with EVs carrying MIF inhibitors.

Thieno[2,3-d]pyrimidine-2,4(1H,3H)-dione Derivative Inhibits d-Dopachrome Tautomerase Activity and Suppresses the Proliferation of Non-Small Cell Lung Cancer Cells

The homologous cytokines macrophage migration inhibitory factor (MIF) and d-dopachrome tautomerase (d-DT or MIF2) play key roles in cancers. Molecules binding to the MIF tautomerase active site interfere with its biological activity. In contrast, the lack of potent MIF2 inhibitors hinders the exploration of MIF2 as a drug target. In this work, screening of a focused compound collection enabled the identification of a MIF2 tautomerase inhibitor R110. Subsequent optimization provided inhibitor 5d with an IC50 of 1.0 μM for MIF2 tautomerase activity and a high selectivity over MIF. 5d suppressed the proliferation of non-small cell lung cancer cells in two-dimensional (2D) and three-dimensional (3D) cell cultures, which can be explained by the induction of cell cycle arrest via deactivation of the mitogen-activated protein kinase (MAPK) pathway. Thus, we discovered and characterized MIF2 inhibitors (5d) with improved antiproliferative activity in cellular models systems, which indicates the potential of targeting MIF2 in cancer treatment.

Breast Cancer Tumor Microenvironment and Molecular Aberrations Hijack Tumoricidal Immunity

Simple Summary

Immune therapy is designed to stimulate tumoricidal effects in a variety of solid tumors including breast carcinomas. However, the emergence of resistant clones leads to treatment failure. Understanding the molecular, cellular, and microenvironmental aberrations is crucial to uncovering underlying mechanisms and developing advanced strategies for preventing or combating these resistant malignancies. This review will summarize research findings revealing various mechanisms employed to hijack innate and adaptive immune surveillance mechanisms, develop hypoxic and tumor promoting metabolism, and foster an immune tolerance microenvironment. In addition, it will highlight potential targets for therapeutic approaches.

Abstract

Breast cancer is the most common malignancy among females in western countries, where women have an overall lifetime risk of >10% for developing invasive breast carcinomas. It is not a single disease but is composed of distinct subtypes associated with different clinical outcomes and is highly heterogeneous in both the molecular and clinical aspects. Although tumor initiation is largely driven by acquired genetic alterations, recent data suggest microenvironment-mediated immune evasion may play an important role in neoplastic progression. Beyond surgical resection, radiation, and chemotherapy, additional therapeutic options include hormonal deactivation, targeted-signaling pathway treatment, DNA repair inhibition, and aberrant epigenetic reversion. Yet, the fatality rate of metastatic breast cancer remains unacceptably high, largely due to treatment resistance and metastases to brain, lung, or bone marrow where tumor bed penetration of therapeutic agents is limited. Recent studies indicate the development of immune-oncological therapy could potentially eradicate this devastating malignancy. Evidence suggests tumors express immunogenic neoantigens but the immunity towards these antigens is frequently muted. Established tumors exhibit immunological tolerance. This tolerance reflects a process of immune suppression elicited by the tumor, and it represents a critical obstacle towards successful antitumor immunotherapy. In general, immune evasive mechanisms adapted by breast cancer encompasses down-regulation of antigen presentations or recognition, lack of immune effector cells, obstruction of anti-tumor immune cell maturation, accumulation of immunosuppressive cells, production of inhibitory cytokines, chemokines or ligands/receptors, and up-regulation of immune checkpoint modulators. Together with altered metabolism and hypoxic conditions, they constitute a permissive tumor microenvironment. This article intends to discern representative incidents and to provide potential innovative therapeutic regimens to reinstate tumoricidal immunity.

Targeting Adipokines in Obesity-Related Tumors

Obesity, a global epidemic, is an independent risk factor for the occurrence and development of a variety of tumors, such as breast cancer, pancreatic cancer, ovarian cancer and colorectal cancer. Adipocytes are important endocrine cells in the tumor microenvironment of obesity-related tumors, which can secrete a variety of adipokines (such as leptin, adiponectin, estrogen, resistin, MIF and MCP-1, etc.), among which leptin, adiponectin and estrogen are the most in-depth and valuable ones. These adipokines are closely related to tumorigenesis and the progression of tumors. In recent years, more and more studies have shown that under chronic inflammatory conditions such as obesity, adipocytes secrete more adipokines to promote the tumorigenesis and development of tumors. However, it is worth noting that although adiponectin is also secreted by adipocytes, it has an anti-tumor effect, and can cross-talk with other adipokines (such as leptin and estrogen) and insulin to play an anti-tumor effect together. In addition, obesity is the main cause of insulin resistance, which can lead to the increase of the expression levels of insulin and insulin-like growth factor (IGF). As important regulators of blood glucose and lipid metabolism, insulin and IGF also play an important role in the progress of obesity related tumors. In view of the important role of adipokines secreted by adipocytes and insulin/IGF in tumors, this article not only elaborates leptin, adiponectin and estrogen secreted by adipocytes and their mechanism of action in the development of obesity- related tumors, but also introduces the relationship between insulin/IGF, a regulator of lipid metabolism, and obesity related tumors. At the same time, it briefly describes the cancer-promoting mechanism of resistin, MIF and MCP-1 in obesity-related tumors, and finally summarizes the specific treatment opinions and measures for various adipokines and insulin/insulin-like growth factors in recent years.

Proteolysis Targeting Chimera (PROTAC) for Macrophage Migration Inhibitory Factor (MIF) Has Anti-Proliferative Activity in Lung Cancer Cells

Macrophage migration inhibitory factor (MIF) is involved in protein-protein interactions that play key roles in inflammation and cancer. Current strategies to develop small molecule modulators of MIF functions are mainly restricted to the MIF tautomerase active site. Here, we use this site to develop proteolysis targeting chimera (PROTAC) in order to eliminate MIF from its protein-protein interaction network. We report the first potent MIF-directed PROTAC, denoted MD13, which induced almost complete MIF degradation at low micromolar concentrations with a DC50 around 100 nM in A549 cells. MD13 suppresses the proliferation of A549 cells, which can be explained by deactivation of the MAPK pathway and subsequent induction of cell cycle arrest at the G2/M phase. MD13 also exhibits antiproliferative effect in a 3D tumor spheroid model. In conclusion, we describe the first MIF-directed PROTAC (MD13) as a research tool, which also demonstrates the potential of PROTACs in cancer therapy.

Tumor-Associated Macrophages as Multifaceted Regulators of Breast Tumor Growth

Breast cancer is the most commonly occurring cancer in women of Western countries and is the leading cause of cancer-related mortality. The breast tumor microenvironment contains immune cells, fibroblasts, adipocytes, mesenchymal stem cells, and extracellular matrix. Among these cells, macrophages or tumor-associated macrophages (TAMs) are the major components of the breast cancer microenvironment. TAMs facilitate metastasis of the breast tumor and are responsible for poor clinical outcomes. High TAM density was also found liable for the poor prognosis of breast cancer. These observations make altering TAM function a potential therapeutic target to treat breast cancer. The present review summarizes the origin of TAMs, mechanisms of macrophage recruitment and polarization in the tumor, and the contributions of TAMs in tumor progression. We have also discussed our current knowledge about TAM-targeted therapies and the roles of miRNAs and exosomes in re-educating TAM function.

Enhancement of β-Glucan Biological Activity Using a Modified Acid-Base Extraction Method from Saccharomyces cerevisiae

Beta glucan (β-glucan) has promising bioactive properties. Consequently, the use of β-glucan as a food additive is favored with the dual-purpose potential of increasing the fiber content of food products and enhancing their health properties. Our aim was to evaluate the biological activity of β-glucan (antimicrobial, antitoxic, immunostimulatory, and anticancer) extracted from Saccharomyces cerevisiae using a modified acid-base extraction method. The results demonstrated that a modified acid-base extraction method gives a higher biological efficacy of β-glucan than in the water extraction method. Using 0.5 mg dry weight of acid-base extracted β-glucan (AB extracted) not only succeeded in removing 100% of aflatoxins, but also had a promising antimicrobial activity against multidrug-resistant bacteria, fungi, and yeast, with minimum inhibitory concentrations (MIC) of 0.39 and 0.19 mg/mL in the case of resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa, respectively. In addition, AB extract exhibited a positive immunomodulatory effect, mediated through the high induction of TNFα, IL-6, IFN-γ, and IL-2. Moreover, AB extract showed a greater anticancer effect against A549, MDA-MB-232, and HepG-2 cells compared to WI-38 cells, at high concentrations. By studying the cell death mechanism using flow-cytometry, AB extract was shown to induce apoptotic cell death at higher concentrations, as in the case of MDA-MB-231 and HePG-2 cells. In conclusion, the use of a modified AB for β-glucan from Saccharomyces cerevisiae exerted a promising antimicrobial, immunomodulatory efficacy, and anti-cancer potential. Future research should focus on evaluating β-glucan in various biological systems and elucidating the underlying mechanism of action.

Nano-delivery systems focused on tumor microenvironment regulation and biomimetic strategies for treatment of breast cancer metastasis

Breast cancer metastasis and recurrence accounts for vast majority of breast cancer-induced mortality. Tumor microenvironment (TME) plays an important role at each step of metastasis, evasion of immunosurveillance, and therapeutic resistance. Consequently, TME-targeting alternatives to traditional therapies focused on breast cancer cells are gaining increasing attention. These new therapies involve the use of tumor cells, and key TME components or secreted bioactive molecules as therapeutic targets, alone or in combination. Recently, TME-related nanoparticles have been developed to deliver various agents, such as bioactive ingredients extracted from natural sources or chemotherapeutic agents, genes, proteins, small interfering RNAs, and vaccines; they have shown great therapeutic potential against breast cancer metastasis. Among various types of nanoparticles, biomimetic nanovesicles are a promising means of addressing the limitations of conventional nanocarriers. This review highlights various nanoparticles related to or mediated by TME according to the key TME components responsible for metastasis. Furthermore, TME-related biomimetic nanoparticles against breast cancer metastasis have garnered attention owing to their promising efficiency, especially in payload delivery and therapeutic action. Here, we summarize recent representative studies on nanoparticles related to cancer-associated fibroblasts, extracellular matrix, endothelial cells, angiogenesis, and immune cells, as well as advanced biomimetic nanoparticles. Future challenges and opportunities in the field are also discussed.

Modulation of Macrophages M1/M2 Polarization Using Carbohydrate-Functionalized Polymeric Nanoparticles

Exploiting surface endocytosis receptors using carbohydrate-conjugated nanocarriers brings outstanding approaches to an efficient delivery towards a specific target. Macrophages are cells of innate immunity found throughout the body. Plasticity of macrophages is evidenced by alterations in phenotypic polarization in response to stimuli, and is associated with changes in effector molecules, receptor expression, and cytokine profile. M1-polarized macrophages are involved in pro-inflammatory responses while M2 macrophages are capable of anti-inflammatory response and tissue repair. Modulation of macrophages’ activation state is an effective approach for several disease therapies, mediated by carbohydrate-coated nanocarriers. In this review, polymeric nanocarriers targeting macrophages are described in terms of production methods and conjugation strategies, highlighting the role of mannose receptor in the polarization of macrophages, and targeting approaches for infectious diseases, cancer immunotherapy, and prevention. Translation of this nanomedicine approach still requires further elucidation of the interaction mechanism between nanocarriers and macrophages towards clinical applications.

Role of Tumor-Associated Myeloid Cells in Breast Cancer

Stromal immune cells constitute the tumor microenvironment. These immune cell subsets include myeloid cells, the so-called tumor-associated myeloid cells (TAMCs), which are of two types: tumor-associated macrophages (TAMs) and myeloid-derived suppressor cells (MDSCs). Breast tumors, particularly those in human epidermal growth factor receptor 2 (HER-2)-positive breast cancer and triple-negative breast cancer, are solid tumors containing immune cell stroma. TAMCs drive breast cancer progression via immune mediated, nonimmune-mediated, and metabolic interactions, thus serving as a potential therapeutic target for breast cancer. TAMC-associated breast cancer treatment approaches potentially involve the inhibition of TAM recruitment, modulation of TAM polarization/differentiation, reduction of TAM products, elimination of MDSCs, and reduction of MDSC products. Furthermore, TAMCs can enhance or restore immune responses during cancer immunotherapy. This review describes the role of TAMs and MDSCs in breast cancer and elucidates the clinical implications of TAMs and MDSCs as potential targets for breast cancer treatment.

Shaping the Innate Immune Response by Dietary Glucans: Any Role in the Control of Cancer?

β-glucans represent a heterogeneous group of naturally occurring and biologically active polysaccharides found in many kinds of edible mushrooms, baker’s yeast, cereals and seaweeds, whose health-promoting effects have been known since ancient times. These compounds can be taken orally as food supplements or as part of daily diets, and are safe to use, nonimmunogenic and well tolerated. A main feature of β-glucans is their capacity to function as biological response modifiers, exerting regulatory effects on inflammation and shaping the effector functions of different innate and adaptive immunity cell populations. The potential to interfere with processes involved in the development or control of cancer makes β-glucans interesting candidates as adjuvants in antitumor therapies as well as in cancer prevention strategies. Here, the regulatory effects of dietary β-glucans on human innate immunity cells are reviewed and their potential role in cancer control is discussed.

siRNA therapeutics for breast cancer: recent efforts in targeting metastasis, drug resistance, and immune evasion

Small interfering RNA (siRNA) has an established and precise mode of action to achieve protein knockdown. With the ability to target any protein, it is very attractive as a potential therapeutic for a plethora of diseases driven by the (over)expression of certain proteins. Utilizing siRNA to understand and treat cancer, a disease largely driven by genetic aberration, is thus actively investigated. However, the main hurdle for the clinical translation of siRNA therapeutics is to achieve effective delivery of siRNA molecules to tumors and the site of action, the cytosol, within cancer cells. Several nanoparticle delivery platforms for siRNA have been developed. In this Review, we describe recent efforts in developing siRNA therapeutics for the treatment of cancer, with particular emphasis on breast cancer. Instead of conventionally targeting proliferation and apoptosis aspects of tumorigenesis, we focus on recent attempts in targeting cancer's metastasis, drug resistance, and immune evasion, which are considered more challenging and less manageable in clinics with current therapeutic molecules. siRNA can target all proteins, including traditionally undruggable proteins, and is thus poised to address these clinical challenges. Evidence also suggests that siRNA can be superior to antibodies or small molecule inhibitors when inhibiting the same druggable pathway. In addition to cancer cells, the role of the tumor microenvironment has been increasingly appreciated. Components in the tumor microenvironment, particularly immune cells, and thus siRNA-based immunotherapy, are under extensive investigation. Lastly, multiple siRNAs with or without additional drugs can be codelivered on the same nanoparticle to the same target site of action, maximizing their potential synergy while limiting off-target toxicity.

Yeast-Derived β-Glucan in Cancer: Novel Uses of a Traditional Therapeutic

An increased understanding of the complex mechanisms at play within the tumor microenvironment (TME) has emphasized the need for the development of strategies that target immune cells within the TME. Therapeutics that render the TME immune-reactive have a vast potential for establishing effective cancer interventions. One such intervention is β-glucan, a natural compound with immune-stimulatory and immunomodulatory potential that has long been considered an important anti-cancer therapeutic. β-glucan has the ability to modulate the TME both by bridging the innate and adaptive arms of the immune system and by modulating the phenotype of immune-suppressive cells to be immune-stimulatory. New roles for β-glucan in cancer therapy are also emerging through an evolving understanding that β-glucan is involved in a concept called trained immunity, where innate cells take on memory phenotypes. Additionally, the hollow structure of particulate β-glucan has recently been harnessed to utilize particulate β-glucan as a delivery vesicle. These new concepts, along with the emerging success of combinatorial approaches to cancer treatment involving β-glucan, suggest that β-glucan may play an essential role in future strategies to prevent and inhibit tumor growth. This review emphasizes the various characteristics of β-glucan, with an emphasis on fungal β-glucan, and highlights novel approaches of β-glucan in cancer therapy.

Tumour growth and immune evasion as targets for a new strategy in advanced cancer

It has become clearer that advanced cancer, especially advanced breast cancer, is an entirely displayed pathological system that is much more complex than previously considered. However, the direct relationship between tumour growth and immune evasion can represent a general rule governing the pathological cancer system from the initial cancer cells to when the system is entirely displayed. Accordingly, a refined pathobiological model and a novel therapeutic strategy are proposed. The novel therapeutic strategy is based on therapeutically induced conditions (undetectable tumour burden and/or a prolonged tumour ‘resting state’), which enable an efficacious immune response in advanced breast and other types of solid cancers.

Targeting Accessories to the Crime: Nanoparticle Nucleic Acid Delivery to the Tumor Microenvironment

Nucleic acid delivery for cancer holds extraordinary promise. Increasing expression of tumor suppressor genes or inhibition of oncogenes in cancer cells has important therapeutic potential. However, several barriers impair progress in cancer gene delivery. These include effective delivery to cancer cells and relevant intracellular compartments. Although viral gene delivery can be effective, it has the disadvantages of being immuno-stimulatory, potentially mutagenic and lacking temporal control. Various nanoparticle (NP) platforms have been developed to overcome nucleic acid delivery hurdles, but several challenges still exist. One such challenge has been the accumulation of NPs in non-cancer cells within the tumor microenvironment (TME) as well as the circulation. While uptake by these cancer-associated cells is considered to be an off-target effect in some contexts, several strategies have now emerged to utilize NP-mediated gene delivery to intentionally alter the TME. For example, the similarity of NPs in shape and size to pathogens promotes uptake by antigen presenting cells, which can be used to increase immune stimulation and promote tumor killing by T-lymphocytes. In the era of immunotherapy, boosting the ability of the immune system to eliminate cancer cells has proven to be an exciting new area in cancer nanotechnology. Given the importance of cancer-associated cells in tumor growth and metastasis, targeting these cells in the TME opens up new therapeutic applications for NPs. This review will cover evidence for non-cancer cell accumulation of NPs in animal models and patients, summarize characteristics that promote NP delivery to different cell types, and describe several therapeutic strategies for gene modification within the TME.

Nanotherapeutic approaches targeting angiogenesis and immune dysfunction in tumor microenvironment

Tumor microenvironment (TME) comprising cellular and non-cellular components is a major source of cancer hallmarks. Notably, angiogenesis responsible for normal physiological remodeling process can otherwise harness vessel abnormalities during tumorigenesis eliciting severe therapeutic inefficiency. Currently, FDA approved antiangiogenic drugs have only shown modest clinical success owing to tumor hypoxia, antiangiogenic therapeutic resistance, and limited knowledge in understanding TME. In order to overcome these limitations, targeting angiogenesis combined with immunosuppressive TME could offer potential therapeutic opportunities. Indeed, these therapeutic approaches can be further revisited with the advent of nanotechnology that can target the key cellular components of TME and tumor cells more precisely. Synergetic targeting without eliciting systemic toxicity achieved by integration of antiangiogenic and immunotherapy in a single nanoplatform is vital for therapeutic success. In this review, we will discuss the most promising nanotechnological advancements oriented to modulate the immunosuppressive TME in association with antiangiogenic therapy that has gained immense popularity in cancer treatment.

Optimizing Tumor Microenvironment for Cancer Immunotherapy: β-Glucan-Based Nanoparticles

Immunotherapy is revolutionizing cancer treatment. Recent clinical success with immune checkpoint inhibitors, chimeric antigen receptor T-cell therapy, and adoptive immune cellular therapies has generated excitement and new hopes for patients and investigators. However, clinically efficacious responses to cancer immunotherapy occur only in a minority of patients. One reason is the tumor microenvironment (TME), which potently inhibits the generation and delivery of optimal antitumor immune responses. As our understanding of TME continues to grow, strategies are being developed to change the TME toward one that augments the emergence of strong antitumor immunity. These strategies include eliminating tumor bulk to provoke the release of tumor antigens, using adjuvants to enhance antigen-presenting cell function, and employ agents that enhance immune cell effector activity. This article reviews the development of β-glucan and β-glucan-based nanoparticles as immune modulators of TME, as well as their potential benefit and future therapeutic applications. Cell-wall β-glucans from natural sources including plant, fungi, and bacteria are molecules that adopt pathogen-associated molecular pattern (PAMP) known to target specific receptors on immune cell subsets. Emerging data suggest that the TME can be actively manipulated by β-glucans and their related nanoparticles. In this review, we discuss the mechanisms of conditioning TME using β-glucan and β-glucan-based nanoparticles, and how this strategy enables future design of optimal combination cancer immunotherapies.

Role of MIF/CD74 signaling pathway in the development of pleural mesothelioma

Macrophage migration inhibitory factor (MIF) is a pro-inflammatory cytokine implicated in acute and chronic inflammatory diseases. MIF is overexpressed in various tumors. It displays a number of functions that provide a direct link between the process of inflammation and tumor growth. Our group recently identified the MIF-receptor CD74 as an independent prognostic factor for overall survival in patients with malignant pleural mesothelioma.

In the present study, we compared the levels of expression of MIF and CD74 in different human mesothelioma cell lines and investigated their physiopathological functions in vitro and in vivo.

Human mesothelioma cells expressed more CD74 and secreted less MIF than non tumoral MeT5A cells, suggesting a higher sensitivity to MIF. In mesothelioma cells, high MIF levels were associated with a high multiplication rate of cells. In vitro, reduction of MIF or CD74 levels in both mesothelioma cell lines showed that the MIF/CD74 signaling pathway promoted tumor cell proliferation and protected MPM cells from apoptosis. Finally, mesothelioma cell lines expressing high CD74 levels had a low tumorigenic potential after xenogeneic implantation in athymic nude mice.

All these data highlight the complexity of the MIF/CD74 signaling pathway in the development of mesothelioma.

CD74 and intratumoral immune response in breast cancer

CD74 (invariant chain) plays a role in MHC class II antigen presentation. We assessed CD74 and MHCII expression in tumor cells, as well as CD8, CD4, and CD68 tumor infiltrating leucocyte (TIL) density by immunohistochemistry in a cohort of 492 breast cancer patients. CD74 expression was associated with poor prognostic markers including patient age, tumor grade, ER status, non-Luminal A subtypes, and with MHCII expression and higher TIL densities, particularly in the Basal-like subgroup. Univariate analysis showed a favorable prognostic effect of CD74 (Hazard ratio = 0.46, 95% CI = 0.26–0.89, p = 0.022) and for combined CD74/MHCII (Hazard ratio = 0.26, 95% CI = 0.17–0.81, p = 0.014) positive status for overall survival that was only manifested in the Basal-like subgroup. CD74 and MHCII expression is associated with patient survival in Basal-like breast cancer, and the association with TIL may reflect an effective intratumoral immune response.

Tumor microenvironment-mediated chemoresistance in breast cancer

Therapy resistance or tumor relapse in cancer is common. Tumors develop resistance to chemotherapeutic through a variety of mechanisms, with tumor microenvironment (TM) serving pivotal roles. Using breast cancer as a paradigm, we propose that responses of cancer cells to drugs are not exclusively determined by their intrinsic characteristics but are also controlled by deriving signals from TM. Affected microenvironment by chemotherapy is an avenue to promote phenotype which tends to resist on to be ruined. Therefore, exclusively targeting cancer cells does not demolish tumor recurrence after chemotherapy. Regardless of tumor-microenvironment pathways and their profound influence on the responsiveness of treatment, diversity of molecular properties of breast cancer also behave differently in terms of response to chemotherapy. And also it is assumed that there is cross-talk between phenotypic diversity and TM. Collectively, raising complex signal from TM in chemotherapy condition often encourages cancer cells are not killed but strengthen. Here, we summarized how TM modifies responses to chemotherapy in breast cancer. We also discussed successful treatment strategies have been considered TM in breast cancer treatment.

Tumor-associated macrophages: unwitting accomplices in breast cancer malignancy

Deleterious inflammation is a primary feature of breast cancer. Accumulating evidence demonstrates that macrophages, the most abundant leukocyte population in mammary tumors, have a critical role at each stage of cancer progression. Such tumor-associated macrophages facilitate neoplastic transformation, tumor immune evasion and the subsequent metastatic cascade. Herein, we discuss the dynamic process whereby molecular and cellular features of the tumor microenvironment act to license tissue-repair mechanisms of macrophages, fostering angiogenesis, metastasis and the support of cancer stem cells. We illustrate how tumors induce, then exploit trophic macrophages to subvert innate and adaptive immune responses capable of destroying malignant cells. Finally, we discuss compelling evidence from murine models of cancer and early clinical trials in support of macrophage-targeted intervention strategies with the potential to dramatically reduce breast cancer morbidity and mortality.