Influence of Innate Immunity on Cancer Cell Stemness

Immune-inflammatory modulation by natural products derived from edible and medicinal herbs used in Chinese classical prescriptions

BACKGROUND

Edible and medicinal herbs1 (EMHs) refer to a class of substances with dual attribution of food and medicine. These substances are traditionally used as food and also listed in many international pharmacopoeias, including the European Pharmacopoeia, the United States Pharmacopoeia, and the Chinese Pharmacopoeia. Some classical formulas that are widely used in traditional Chinese medicine include a series of EMHs, which have been shown to be effective with obvious characteristics and advantages. Notably, these EMHs and Chinese classical prescriptions2 (CCPs) have also attracted attention in international herbal medicine research because of their low toxicity and high efficiency as well as the rich body of experience for their long-term clinical use.

PURPOSE

Our purpose is to explore the potential therapeutic effect of EMHs with immune-inflammatory modulation for the study of modern cancer drugs.

STUDY DESIGN

In the present study, we present a detailed account of some EMHs used in CCPs that have shown considerable research potential in studies exploring modern drugs with immune-inflammatory modulation.

METHODS

Approximately 500 publications in the past 30 years were collected from PubMed, Web of Science and ScienceDirect using the keywords, such as natural products, edible and medicinal herbs, Chinese medicine, classical prescription, immune-inflammatory, tumor microenvironment and some related synonyms. The active ingredients instead of herbal extracts or botanical mixtures were focused on and the research conducted over the past decade were discussed emphatically and analyzed comprehensively.

RESULTS

More than ten natural products derived from EMHs used in CCPs are discussed and their immune-inflammatory modulation activities, including enhancing antitumor immunity, regulating inflammatory signaling pathways, lowering the proportion of immunosuppressive cells, inhibiting the secretion of proinflammatory cytokines, immunosuppressive factors, and inflammatory mediators, are summarized.

CONCLUSION

Our findings demonstrate the immune-inflammatory modulating role of those EMHs used in CCPs and provide new ideas for cancer treatment in clinical settings.

Immunobiology of cancer stem cells and their immunoevasion mechanisms

Cancer stem cells (CSCs) defined as a small fraction of cells within malignancies have been isolated from tumors with different histological origins with stem related characteristics such as self-replicating potential, tumorigenesis, and therapy resistance. The dynamic communication between CSCs and tumor microenvironment particularly immune cells orchestrates their fate and plasticity as well as the patient outcome. According to recent evidence, it has been reported that they harness different immunological pathways to escape immunosurveillance and express aberrantly immunomodulatory agents or decreased levels of factors forming antigen presenting machinery (APM), subsequently followed by impaired antigen presentation and suppressed immune detection. As effective therapies are expected to be able to eradicate CSCs, mechanistic understanding of such interactions can provide insights into causes of therapy failure particularly in immunotherapy. Also, it can contribute to enhance the practical interventions against CSCs and their immunomodulatory features resulting in CSCs eradication and improving patient clinical outcome. The aim of this review is to explain the present knowledge regarding the immunobiology of CSCs and the immunoevasion mechanisms they use.

Characterization of stemness features and construction of a stemness subtype classifier to predict survival and treatment responses in lung squamous cell carcinoma

BACKGROUND

Cancer stemness has been proven to affect tumorigenesis, metastasis, and drug resistance in various cancers, including lung squamous cell carcinoma (LUSC). We intended to develop a clinically applicable stemness subtype classifier that could assist physicians in predicting patient prognosis and treatment response.

METHODS

This study collected RNA-seq data from TCGA and GEO databases to calculate transcriptional stemness indices (mRNAsi) using the one-class logistic regression machine learning algorithm. Unsupervised consensus clustering was conducted to identify a stemness-based classification. Immune infiltration analysis (ESTIMATE and ssGSEA algorithms) methods were used to investigate the immune infiltration status of different subtypes. Tumor Immune Dysfunction and Exclusion (TIDE) and Immunophenotype Score (IPS) were used to evaluate the immunotherapy response. The pRRophetic algorithm was used to estimate the efficiency of chemotherapeutic and targeted agents. Two machine learning algorithms (LASSO and RF) and multivariate logistic regression analysis were performed to construct a novel stemness-related classifier.

RESULTS

We observed that patients in the high-mRNAsi group had a better prognosis than those in the low-mRNAsi group. Next, we identified 190 stemness-related differentially expressed genes (DEGs) that could categorize LUSC patients into two stemness subtypes. Patients in the stemness subtype B group with higher mRNAsi scores exhibited better overall survival (OS) than those in the stemness subtype A group. Immunotherapy prediction demonstrated that stemness subtype A has a better response to immune checkpoint inhibitors (ICIs). Furthermore, the drug response prediction indicated that stemness subtype A had a better response to chemotherapy but was more resistant to epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs). Finally, we constructed a nine-gene-based classifier to predict patients' stemness subtype and validated it in independent GEO validation sets. The expression levels of these genes were also validated in clinical tumor specimens.

CONCLUSION

The stemness-related classifier could serve as a potential prognostic and treatment predictor and assist physicians in selecting effective treatment strategies for patients with LUSC in clinical practice.

Cancer Stem Cell Relationship with Pro-Tumoral Inflammatory Microenvironment

Inflammatory processes and cancer stem cells (CSCs) are increasingly recognized as factors in the development of tumors. Emerging evidence indicates that CSCs are associated with cancer properties such as metastasis, treatment resistance, and disease recurrence. However, the precise interaction between CSCs and the immune microenvironment remains unexplored. Although evasion of the immune system by CSCs has been extensively studied, new research demonstrates that CSCs can also control and even profit from the immune response. This review provides an overview of the reciprocal interplay between CSCs and tumor-infiltrating immune cells, collecting pertinent data about how CSCs stimulate leukocyte reprogramming, resulting in pro-tumor immune cells that promote metastasis, chemoresistance, tumorigenicity, and even a rise in the number of CSCs. Tumor-associated macrophages, neutrophils, Th17 and regulatory T cells, mesenchymal stem cells, and cancer-associated fibroblasts, as well as the signaling pathways involved in these pro-tumor activities, are among the immune cells studied. Although cytotoxic leukocytes have the potential to eliminate CSCs, immune evasion mechanisms in CSCs and their clinical implications are also known. We intended to compile experimental findings that provide direct evidence of interactions between CSCs and the immune system and CSCs and the inflammatory milieu. In addition, we aimed to summarize key concepts in order to comprehend the cross-talk between CSCs and the tumor microenvironment as a crucial process for the effective design of anti-CSC therapies.

Natural Killer Cells Are Key Host Immune Effector Cells Affecting Survival in Autologous Peripheral Blood Hematopoietic Stem Cell Transplantation

The infusion of autograft immune effector cells directly impacts the clinical outcomes of patients treated with autologous peripheral blood hematopoietic stem cell transplantation, suggesting the possibility of an autologous graft-versus tumor cells. Furthermore, the early recovery of immune effector cells also affects survival post-autologous peripheral blood hematopoietic stem cell transplantation. Natural killer cells are among the immune effector cells reported to be collected, infused, and recovered early post-autologous peripheral blood hematopoietic stem cell transplantation. In this review, I attempt to give an update on the role of natural killer cells regarding improving survival outcomes on patients treated with autologous peripheral blood hematopoietic stem cell transplantation.

Cancer Stem Cells in Ovarian Cancer-A Source of Tumor Success and a Challenging Target for Novel Therapies

Ovarian cancer is the most lethal neoplasm of the female genital organs. Despite indisputable progress in the treatment of ovarian cancer, the problems of chemo-resistance and recurrent disease are the main obstacles for successful therapy. One of the main reasons for this is the presence of a specific cell population of cancer stem cells. The aim of this review is to show the most contemporary knowledge concerning the biology of ovarian cancer stem cells (OCSCs) and their impact on chemo-resistance and prognosis in ovarian cancer patients, as well as to present the treatment options targeted exclusively on the OCSCs. The review presents data concerning the role of cancer stem cells in general and then concentrates on OCSCs. The surface and intracellular OCSCs markers and their meaning both for cancer biology and clinical prognosis, signaling pathways specifically activated in OCSCs, the genetic and epigenetic regulation of OCSCs function including the recent studies on the non-coding RNA regulation, cooperation between OCSCs and the tumor microenvironment (ovarian cancer niche) including very specific environment such as ascites fluid, the role of shear stress, autophagy and metabolic changes for the function of OCSCs, and finally mechanisms of OCSCs escape from immune surveillance, are described and discussed extensively. The possibilities of anti-OCSCs therapy both in experimental settings and in clinical trials are presented, including the recent II phase clinical trials and immunotherapy. OCSCs are a unique population of cancer cells showing a great plasticity, self-renewal potential and resistance against anti-cancer treatment. They are responsible for the progression and recurrence of the tumor. Several completed and ongoing clinical trials have tested different anti-OCSCs drugs which, however, have shown unsatisfactory efficacy in most cases. We propose a novel approach to ovarian cancer diagnosis and therapy.

Dissecting Tumor Growth: The Role of Cancer Stem Cells in Drug Resistance and Recurrence

Simple Summary

Cancer is one of the most debated problems all over the world. Cancer stem cells are considered responsible of tumor initiation, metastasis, drug resistance, and recurrence. This subpopulation of cells has been found into the tumor bulk and showed the capacity to self-renew, differentiate, up to generate a new tumor. In the last decades, several studies have been set on the molecular mechanisms behind their specific characteristics as the Wnt/β-catenin signaling, Notch signaling, Hedgehog signaling, transcription factors, etc. The most powerful part of CSCs is represented by the niches as “promoter” of their self-renewal and “protector” from the common oncological treatment as chemotherapy and radiotherapy. In our review article we highlighted the primary mechanisms involved in CSC tumorigenesis for the setting of further targets to control the metastatic process.

Abstract

Emerging evidence suggests that a small subpopulation of cancer stem cells (CSCs) is responsible for initiation, progression, and metastasis cascade in tumors. CSCs share characteristics with normal stem cells, i.e., self-renewal and differentiation potential, suggesting that they can drive cancer progression. Consequently, targeting CSCs to prevent tumor growth or regrowth might offer a chance to lead the fight against cancer. CSCs create their niche, a specific area within tissue with a unique microenvironment that sustains their vital functions. Interactions between CSCs and their niches play a critical role in regulating CSCs’ self-renewal and tumorigenesis. Differences observed in the frequency of CSCs, due to the phenotypic plasticity of many cancer cells, remain a challenge in cancer therapeutics, since CSCs can modulate their transcriptional activities into a more stem-like state to protect themselves from destruction. This plasticity represents an essential step for future therapeutic approaches. Regarding self-renewal, CSCs are modulated by the same molecular pathways found in normal stem cells, such as Wnt/β-catenin signaling, Notch signaling, and Hedgehog signaling. Another key characteristic of CSCs is their resistance to standard chemotherapy and radiotherapy treatments, due to their capacity to rest in a quiescent state. This review will analyze the primary mechanisms involved in CSC tumorigenesis, with particular attention to the roles of CSCs in tumor progression in benign and malignant diseases; and will examine future perspectives on the identification of new markers to better control tumorigenesis, as well as dissecting the metastasis process.

Evolution and Targeting of Myeloid Suppressor Cells in Cancer: A Translational Perspective

Simple Summary

Immunotherapy is achieving impressive results in the treatment of several cancers. While the main strategies aim to re-invigorate the specific lymphocyte anti-tumor response, many studies underline that altered myeloid cell frequency and functions can dramatically interfere with the responsiveness to cancer therapies. Therefore, many novel strategies targeting TAMs and MDSCs in combination with classical treatments are under continuous evolution at both pre-clinical and clinical levels, showing encouraging results. Herein, we depict a comprehensive overview of myeloid cell generation and function in a cancer setting, and the most relevant strategies for their targeting that are currently in clinical use or under pre-clinical development.

Abstract

In recent years, the immune system has emerged as a critical regulator of tumor development, progression and dissemination. Advanced therapeutic approaches targeting immune cells are currently under clinical use and improvement for the treatment of patients affected by advanced malignancies. Among these, anti-PD1/PD-L1 and anti-CTLA4 immune checkpoint inhibitors (ICIs) are the most effective immunotherapeutic drugs at present. In spite of these advances, great variability in responses to therapy exists among patients, probably due to the heterogeneity of both cancer cells and immune responses, which manifest in diverse forms in the tumor microenvironment (TME). The variability of the immune profile within TME and its prognostic significance largely depend on the frequency of the infiltrating myeloid cells, which often represent the predominant population, characterized by high phenotypic heterogeneity. The generation of heterogeneous myeloid populations endowed with tumor-promoting activities is typically promoted by growing tumors, indicating the sequential levels of myeloid reprogramming as possible antitumor targets. This work reviews the current knowledge on the events governing protumoral myelopoiesis, analyzing the mechanisms that drive the expansion of major myeloid subsets, as well as their functional properties, and highlighting recent translational strategies for clinical developments.

Targeting monocytes/macrophages in fibrosis and cancer diseases: Therapeutic approaches

Over almost 140 years since their identification, the knowledge about macrophages has unbelievably evolved. The 'big eaters' from being thought of as simple phagocytic cells have been recognized as master regulators in immunity, homeostasis, healing/repair and organ development. Long considered to originate exclusively from bone marrow-derived circulating monocytes, macrophages have been also demonstrated to be the first immune cells colonizing tissues in the developing embryo and persisting in adult life by self-renewal, as long-lived tissue resident macrophages. Therefore, heterogeneous populations of macrophages with different ontogeny and functions co-exist in tissues. Macrophages act as sentinels of homeostasis and are intrinsically programmed to lead the wound healing and repair processes that occur after injury. However, in certain pathological circumstances macrophages get dysfunctional, and impaired or aberrant macrophage activities become key features of diseases. For instance, in both fibrosis and cancer, that have been defined 'wounds that do not heal', dysfunctional monocyte-derived macrophages overall play a key detrimental role. On the other hand, due to their plasticity these cells can be 're-educated' and exert anti-fibrotic and anti-cancer functions. Therefore macrophages represent an important therapeutic target in both fibrosis and cancer diseases. The current review will illustrate new insights into the role of monocytes/macrophages in these devastating diseases and summarize new therapeutic strategies and applications of macrophage-targeted drug development in their clinical setting.

Inflammasome Signaling: A Novel Paradigm of Hub Platform in Innate Immunity for Cancer Immunology and Immunotherapy

Inflammasomes are fundamental innate immune mechanisms that promote inflammation and induce an inflammatory form of programmed cell death, pyroptosis. Pyroptotic inflammasome has been reported to be closely associated with tumorigenesis and prognosis of multiple cancers. Emerging studies show that the inflammasome assembly into a higher-order supramolecular complex has been utilized to evaluate the status of the innate immune response. The inflammasomes are now regarded as cellular signaling hubs of the innate immunity that drive the production of inflammatory cytokines and consequent recruitment of immune cells to the tumor sites. Herein, we provided an overview of molecular characteristics and biological properties of canonical and non-canonical inflammasome signaling in cancer immunology and immunotherapy. We also focus on the mechanism of regulating pyroptotic inflammasome in tumor cells, as well as the potential roles of inflammasome-mediated pyroptotic cell death in cancers, to explore the potential diagnostic and therapeutic markers contributing to the prevention and treatment of cancers.

Exosomes and Cancer Stem Cells in Cancer Immunity: Current Reports and Future Directions

Cancer stem cells (CSCs), which have the capacity to self-renew and differentiate into various types of cells, are notorious for their roles in tumor initiation, metastasis, and therapy resistance. Thus, underlying mechanisms for their survival provide key insights into developing effective therapeutic strategies. A more recent focus has been on exosomes that play a role in transmitting information between CSCs and non-CSCs, resulting in activating CSCs for cancer progression and modulating their surrounding microenvironment. The field of CSC-derived exosomes (CSCEXs) for different types of cancer is still under exploration. A deeper understanding and further investigation into CSCEXs’ roles in tumorigenicity and the identification of novel exosomal components are necessary for engineering exosomes for the treatment of cancer. Here, we review the features of CSCEXs, including surface markers, cargo, and biological or physiological functions. Further, reports on the immunomodulatory effects of CSCEXs are summarized, and exosome engineering for CSC-targeting is also discussed.

Cancer metastasis as a non-healing wound

Most cancer deaths are caused by metastasis: recurrence of disease by disseminated tumour cells at sites distant from the primary tumour. Large numbers of disseminated tumour cells are released from the primary tumour, even during the early stages of tumour growth. However, only a minority survive as potential seeds for future metastatic outgrowths. These cells must adapt to a relatively inhospitable microenvironment, evade immune surveillance and progress from the micro- to macro-metastatic stage to generate a secondary tumour. A pervasive driver of this transition is chronic inflammatory signalling emanating from tumour cells themselves. These signals can promote migration and engagement of stem and progenitor cell function, events that are also central to a wound healing response. In this review, we revisit the concept of cancer as a non-healing wound, first introduced by Virchow in the 19th century, with a new tumour cell-intrinsic perspective on inflammation and focus on metastasis. Cellular responses to inflammation in both wound healing and metastasis are tightly regulated by crosstalk with the surrounding microenvironment. Targeting or restoring canonical responses to inflammation could represent a novel strategy to prevent the lethal spread of cancer.

Natural Polysaccharides and Their Derivates: A Promising Natural Adjuvant for Tumor Immunotherapy

The treatment process of tumor is advanced with the development of immunotherapy. In clinical experience, immunotherapy has achieved very significant results. However, the application of immunotherapy is limited by a variety of immune microenvironment. For a long time in the past, polysaccharides such as lentinan and Ganoderma lucidum glycopeptide have been used in clinic as adjuvant drugs to widely improve the immunity of the body. However, their mechanism in tumor immunotherapy has not been deeply discussed. Studies have shown that natural polysaccharides can stimulate innate immunity by activating upstream immune cells so as to regulate adaptive immune pathways such as T cells and improve the effect of immunotherapy, suggesting that polysaccharides also have a promising future in cancer therapy. This review systematically discusses that polysaccharides can directly or indirectly activate macrophages, dendritic cells, natural killer cells etc., binding to their surface receptors, inducing PI3K/Akt, mitogen-activated protein kinase, Notch and other pathways, promote their proliferation and differentiation, increasing the secretion of cytokines, and improve the state of immune suppression. These results provide relevant basis for guiding polysaccharide to be used as adjuvants of cancer immunotherapy.

Tumor-associated myeloid cells: diversity and therapeutic targeting

Myeloid cells in tumor tissues constitute a dynamic immune population characterized by a non-uniform phenotype and diverse functional activities. Both tumor-associated macrophages (TAMs), which are more abundantly represented, and tumor-associated neutrophils (TANs) are known to sustain tumor cell growth and invasion, support neoangiogenesis and suppress anticancer adaptive immune responses. In recent decades, several therapeutic approaches have been implemented in preclinical cancer models to neutralize the tumor-promoting roles of both TAMs and TANs. Some of the most successful strategies have now reached the clinic and are being investigated in clinical trials. In this review, we provide an overview of the recent literature on the ever-growing complexity of the biology of TAMs and TANs and the development of the most promising approaches to target these populations therapeutically in cancer patients.

Esculentosides: Insights into the potential health benefits, mechanisms of action and molecular targets

BACKGROUND

Esculentosides and related phytolaccosides form a group of oleanene-type saponins isolated from plants of the Phytolaccaceae family, essentially Phytolacca esculenta, P. americana and P. acinosa. This chemical family offers a diversity of glycosylated compounds, including molecules with a mono-, di- or tri-saccharide unit at position C-3, and with or without a glucose residue at position C-28. The esculentosides, which derive essentially from the sapogenin jaligonic acid or its 30-methyl ester phytolaccagenin, exhibit anti-inflammatory, antifungal and anticancer activities.

PURPOSE

The objective of the review was to identify the 26 esculentosides (ES) and phytolaccosides known to date, including 16 monodesmosidic and 10 bidesmosidic saponins, and to review their pharmacological properties and molecular targets.

METHODOLOGY

The retrieval of potentially relevant studies was done by systematically searching of scientific databases like Google Scholar and PubMed in January-May 2020. The main keywords used as search terms were related to esculentosides, phytolaccosides and Phytolaccaceae. The systematic search retrieved about 110 papers that were potentially relevant and after an abstract-based selection, 68 studies were analyzed in details and discussed.

RESULTS

The structural relationship between the compounds and their sapogenin precursors has been studied. In addition, the pharmacological properties of the main ES, such as ES-A, -B and -H, have been analyzed to highlight their mode of action and potential targets. ES-A is a potent inhibitor of the release of cytokines and this anti-inflammatory activity contributes to the anticancer effects observed in vitro and in vivo. Potential molecular targets of ES-A/B include the enzymes cyclooxygenase 2 (COX-2) and casein kinase 2 (CK2). In addition, the targeting of the protein high-mobility group box 1 (HGMB1) by ES-A/B is proposed, based on molecular modeling and the structural analogy with the related saponin glycyrrhizin, a potent HGMB1 alarmin inhibitor.

CONCLUSION

More work is needed to properly characterize the molecular targets but otherwise compounds like ES-A and ES-H emerge as potent anti-inflammatory and anticancer agents and ES-B as an antifungal agent. A preclinical development of these three compounds should be considered.

Stem Cells: Current Status and Therapeutic Implications

Cancer stem cells (CSCs) are a class of pluripotent cells that have been observed in most types of cancers. Evolving evidence suggests that CSCs, has the ability to self-renew and initiate tumors, may be responsible for promoting therapeutic resistance, tumor recurrence and metastasis. Tumor heterogeneity is originating from CSCs and its progenitors are recognized as major difficulty in efficaciously treating cancer patients. Therefore, understanding the biological mechanisms by which CSCs survive chemo- and-radiation therapy has the potential to identify new therapeutic strategies in the future. In this review, we summarized recent advances in CSC biology and their environment, and discuss about the potential therapies to prevent therapeutic resistance.

Development of Cancer in Patients With Heart Failure: How Systemic Inflammation Can Lay the Groundwork

In the last decade, cardiologists and oncologists have provided clinical and experimental evidence that cancer, and not only chemotherapeutic agents, can cause detrimental effects on heart structure and function, a consequence that has serious clinical implications for patient management. In parallel, the intriguing idea that heart failure (HF) may be an oncogenic condition has also received growing attention. A number of epidemiological and clinical studies have reported that patients with HF have a higher risk of developing cancer. Chronic low-grade systemic inflammation has been proposed as a major pathophysiological process linking the failing heart to the multi-step process of carcinogenesis. According to this view, pro-inflammatory mediators secreted by the damaged heart generate a favorable milieu that promotes tumor development and accelerates malignant transformation. HF-associated inflammation synergizes with tumor-associated inflammation, so that over time it is no longer possible to distinguish the effects of one or the other. Experimental studies have just begun to search for the molecular effectors of this process, with the ultimate goal that of identifying mechanisms suitable for anti-cancer target therapy to reduce the risk of incident cancer in patients already affected by HF. In this review we critically discuss strengths and limitations of clinical and experimental studies that support a causal relationship between HF and cancer, and focus on HF-associated inflammation, cardiokines and their endocrine functions linking one and the other disease.