Breast cancer instructs dendritic cells to prime interleukin 13-secreting CD4+ T cells that facilitate tumor development

Immune Cell Migration to Cancer

Immune cell migration is required for the development of an effective and robust immune response. This elegant process is regulated by both cellular and environmental factors, with variables such as immune cell state, anatomical location, and disease state that govern differences in migration patterns. In all cases, a major factor is the expression of cell surface receptors and their cognate ligands. Rapid adaptation to environmental conditions partly depends on intrinsic cellular immune factors that affect a cell's ability to adjust to new environment. In this review, we discuss both myeloid and lymphoid cells and outline key determinants that govern immune cell migration, including molecules required for immune cell adhesion, modes of migration, chemotaxis, and specific chemokine signaling. Furthermore, we summarize tumor-specific elements that contribute to immune cell trafficking to cancer, while also exploring microenvironment factors that can alter these cellular dynamics within the tumor in both a pro and antitumor fashion. Specifically, we highlight the importance of the secretome in these later aspects. This review considers a myriad of factors that impact immune cell trajectory in cancer. We aim to highlight the immunotherapeutic targets that can be harnessed to achieve controlled immune trafficking to and within tumors.

Upregulation of CCNB2 and a novel lncRNAs-related risk model predict prognosis in clear cell renal cell carcinoma

BACKGROUND

Clear cell renal cell carcinoma (ccRCC) is the main type of renal cell carcinoma. Cyclin B2 (CCNB2) is a subtype of B-type cyclin that is associated with the prognosis of several cancers. This study aimed to identify the relationship between CCNB2 and progression of ccRCC and construct a novel lncRNAs-related model to predict prognosis of ccRCC patients.

METHODS

The data were obtained from public databases. We identified CCNB2 in ccRCC using Kaplan-Meier survival analysis, univariate and multivariate Cox regression, and Gene Ontology analysis. External validation was then performed. The risk model was constructed based on prognostic lncRNAs by the LASSO algorithm and multivariate Cox regression. Receiver operating characteristics (ROC) curves were used to evaluate the model. Consensus clustering analysis was performed to re-stratify the patients. Finally, we analyzed the tumor-immune microenvironment and performed screening of potential drugs.

RESULTS

CCNB2 associated with late clinicopathological parameters and poor prognosis in ccRCC and was an independent predictor for disease-free survival. In addition, CCNB2 shared the same expression pattern with known suppressive immune checkpoints. A risk model dependent on the expression of three prognostic CCNB2-related lncRNAs (SNHG17, VPS9D1-AS1, and ZMIZ1-AS1) was constructed. The risk signature was an independent predictor of ccRCC. The area under the ROC (AUC) curve for overall survival at 1-, 3-, 5-, and 8-year was 0.704, 0.702, 0.741, and 0.763. The high-risk group and cluster 2 had stronger immunogenicity and were more sensitive to immunotherapy.

CONCLUSION

CCNB2 could be an important biomarker for predicting prognosis in ccRCC patients. Furthermore, we developed a novel lncRNAs-related risk model and identified two CCNB2-related molecular clusters. The risk model performed well in predicting overall survival and immunological microenvironment of ccRCC.

Improving targeted small molecule drugs to overcome chemotherapy resistance

BACKGROUND

Conventional cancer treatments face the challenge of therapeutic resistance, which causes poor treatment outcomes. The use of combination therapies can improve treatment results in patients and is one of the solutions to overcome this challenge. Chemotherapy is one of the conventional treatments that, due to the non-targeted and lack of specificity in targeting cancer cells, can cause serious complications in the short and long-term for patients by damaging healthy cells. Also, the employment of a wide range of strategies for chemotherapy resistance by cancer cells, metastasis, and cancer recurrence create serious problems to achieve the desired results of chemotherapy. Accordingly, targeted therapies can be used as a combination treatment with chemotherapy to both cause less damage to healthy cells, which as a result, they reduce the side effects of chemotherapy, and by targeting the factors that cause therapeutic challenges, can improve the results of chemotherapy in patients.

RECENT FINDINGS

Small molecules are one of the main targeted therapies that can be used for diverse targets in cancer treatment due to their penetration ability and characteristics. However, small molecules in cancer treatment are facing obstacles that a better understanding of cancer biology, as well as the mechanisms and factors involved in chemotherapy resistance, can lead to the improvement of this type of major targeted therapy.

CONCLUSION

In this review article, at first, the challenges that lead to not achieving the desired results in chemotherapy and how cancer cells can be resistant to chemotherapy are examined, and at the end, research areas are suggested that more focusing on them, can lead to the improvement of the results of using targeted small molecules as an adjunctive treatment for chemotherapy in the conditions of chemotherapy resistance and metastasis of cancer cells.

Dual Functions of T Lymphocytes in Breast Carcinoma: From Immune Protection to Orchestrating Tumor Progression and Metastasis

Breast cancer (BC) is the most common cancer type in women and the second leading cause of death. Despite recent advances, the mortality rate of BC is still high, highlighting a need to develop new treatment strategies including the modulation of the immune system and immunotherapies. In this regard, understanding the complex function of the involved immune cells and their crosstalk with tumor cells is of great importance. T-cells are recognized as the most important cells in the tumor microenvironment and are divided into several subtypes including helper, cytotoxic, and regulatory T-cells according to their transcription factors, markers, and functions. This article attempts to provide a comprehensive review of the role of T-cell subsets in the prognosis and treatment of patients with BC, and crosstalk between tumor cells and T-cells. The literature overwhelmingly contains controversial findings mainly due to the plasticity of T-cell subsets within the inflammatory conditions and the use of different panels for their phenotyping. However, investigating the role of T-cells in BC immunity depends on a variety of factors including tumor types or subtypes, the stage of the disease, the localization of the cells in the tumor tissue and the presence of different cells or cytokines.

A pancancer analysis of the oncogenic role of cyclin B1 (CCNB1) in human tumors

Aberrant levels of the G2/M cyclin cyclin B1 (gene CCNB1) have been associated with multiple cancers; however, the literature lacks a focused and comprehensive analysis of the regulation of this important regulator of cell proliferation in cancer. Through this work, we performed a pancancer analysis of the levels of CCNB1 and dissected aspects of regulation and how this correlates with cancer prognosis. We comprehensively evaluated the expression and promoter methylation of CCNB1 across 38 cancers based on RNA sequencing data obtained from the Cancer Genome Atlas (TCGA). The correlation of CCNB1 with prognosis and the tumor microenvironment was explored. Using lung adenocarcinoma data, we studied the potential upstream noncoding RNAs involved in the regulation of CCNB1 and validated the protein levels and prognostic value of CCNB1 for this disease site. CCNB1 was highly expressed, and promoter methylation was reduced in most cancers. Gene expression of CCNB1 correlated positively with poor prognosis of tumor patients, and these results were confirmed at the protein level using lung adenocarcinoma. CCNB1 expression was associated with the infiltration of T helper cells, and this further correlated with poor prognosis for certain cancers, including renal clear cell carcinoma and lung adenocarcinoma. Subsequently, we identified a specific upstream noncoding RNA contributing to CCNB1 overexpression in lung adenocarcinoma through correlation analysis, expression analysis and survival analysis. This study provides a comprehensive analysis of the expression and methylation status of CCNB1 across several forms of cancer and provides further insight into the mechanistic pathways regulating Cyclin B1 in the tumorigenesis process.

The deformation of cancer cells through narrow micropores holds the potential to regulate genes that impact cancer malignancy

Surgery, radiation, hormonal therapy, chemotherapy, and immunotherapy are standard treatment strategies for metastatic breast cancer. However, the heterogeneous nature of the disease poses challenges and continues to make it life-threatening. It is crucial to elucidate further the underlying signaling pathways to improve treatment efficacy. Our study established two triple-negative breast cancer cell lines (TW-1 and TW-2) that were physically deformed using 3 μm pores to investigate the relationship between cancer cell deformation and metastasis within a heterogeneous population. The physical transformation of TW-1 and TW-2 cells significantly affected their growth and migration speed, as evidenced by wound healing assays for collective cell migration and microchannel assays for single-cell migration. We conducted bulk RNA sequencing to gain insights into the genes influenced by physical deformation. Additionally, we evaluated the effects of trametinib resistance on breast cancer cell metastasis by assessing cell viability and migration rates. Interestingly, TW-1 and TW-2 cells exhibited resistance to trametinib treatment. We observed a significant upregulation of GABRA-3, a protein commonly expressed in malignant breast cancer, and the critical transcription factor Myc in TW-1 and TW-2 cells compared to the control group (Ori). However, we did not observe a significant difference in Myc expression between TW-1 and TW-2 cells. In contrast, in the trametinib-resistant cell lines (TW-1-Tra and TW-2-Tra), we found increased expression of OCT4 and SOX2 rather than GABRA-3 or Myc. These findings highlight the differential expression patterns of these genes in our study, suggesting their potential role in cancer cell deformation and drug resistance. Our study presents a potential in vitro model for metastatic and drug-resistant breast cancer cells. By investigating the correlation between cancer cell deformation and metastasis, we contribute to understanding breast cancer heterogeneity and lay the groundwork for developing improved treatment strategies.

Unveiling tumor immune evasion mechanisms: abnormal expression of transporters on immune cells in the tumor microenvironment

The tumor microenvironment (TME) is a crucial driving factor for tumor progression and it can hinder the body's immune response by altering the metabolic activity of immune cells. Both tumor and immune cells maintain their proliferative characteristics and physiological functions through transporter-mediated regulation of nutrient acquisition and metabolite efflux. Transporters also play an important role in modulating immune responses in the TME. In this review, we outline the metabolic characteristics of the TME and systematically elaborate on the effects of abundant metabolites on immune cell function and transporter expression. We also discuss the mechanism of tumor immune escape due to transporter dysfunction. Finally, we introduce some transporter-targeted antitumor therapeutic strategies, with the aim of providing new insights into the development of antitumor drugs and rational drug usage for clinical cancer therapy.

Reshaping immunometabolism in the tumour microenvironment to improve cancer immunotherapy

The evolving understanding of cellular metabolism has revealed a the promise of strategies aiming to modulate anticancer immunity by targeting metabolism. The combination of metabolic inhibitors with immune checkpoint blockade (ICB), chemotherapy and radiotherapy may offer new approaches to cancer treatment. However, it remains unclear how these strategies can be better utilized despite the complex tumour microenvironment (TME). Oncogene-driven metabolic changes in tumour cells can affect the TME, limiting the immune response and creating many barriers to cancer immunotherapy. These changes also reveal opportunities to reshape the TME to restore immunity by targeting metabolic pathways. Further exploration is required to determine how to make better use of these mechanistic targets. Here, we review the mechanisms by which tumour cells reshape the TME and cause immune cells to transition into an abnormal state by secreting multiple factors, with the ultimate goal of proposing targets and optimizing the use of metabolic inhibitors. Deepening our understanding of changes in metabolism and immune function in the TME will help advance this promising field and enhance immunotherapy.

Impact of the Cancer Cell Secretome in Driving Breast Cancer Progression

Breast cancer is a complex and heterogeneous disease resulting from the accumulation of genetic and epigenetic alterations in breast epithelial cells. Despite remarkable progress in diagnosis and treatment, breast cancer continues to be the most prevalent cancer affecting women worldwide. Recent research has uncovered a compelling link between breast cancer onset and the extracellular environment enveloping tumor cells. The complex network of proteins secreted by cancer cells and other cellular components within the tumor microenvironment has emerged as a critical player in driving the disease's metastatic properties. Specifically, the proteins released by the tumor cells termed the secretome, can significantly influence the progression and metastasis of breast cancer. The breast cancer cell secretome promotes tumorigenesis through its ability to modulate growth-associated signaling pathways, reshaping the tumor microenvironment, supporting pre-metastatic niche formation, and facilitating immunosurveillance evasion. Additionally, the secretome has been shown to play a crucial role in drug resistance development, making it an attractive target for cancer therapy. Understanding the intricate role of the cancer cell secretome in breast cancer progression will provide new insights into the underlying mechanisms of this disease and aid in the development of more innovative therapeutic interventions. Hence, this review provides a nuanced analysis of the impact of the cancer cell secretome on breast cancer progression, elucidates the complex reciprocal interaction with the components of the tumor microenvironment and highlights emerging therapeutic opportunities for targeting the constituents of the secretome.

Tertiary Lymphoid Structures (TLSs) and Stromal Blood Vessels Have Significant and Heterogeneous Impact on Recurrence, Lymphovascular and Perineural Invasion amongst Breast Cancer Molecular Subtypes

BACKGROUND

Tertiary lymphoid structures (TLSs) mediate local antitumor immunity, and interest in them significantly increased since cancer immunotherapy was implemented. We examined TLS- tumor stromal blood vessel interplay for each breast cancer (BC) molecular subtype related to recurrence, lymphovascular invasion (LVI), and perineural invasion (PnI).

METHODS

TLSs were quantified on hematoxylin and eosin stain specimens followed by CD34/smooth muscle actin (SMA) double immunostaining for stromal blood vessel maturation assessment. Statistical analysis linked microscopy to recurrence, LVI, and PnI.

RESULTS

TLS negative (TLS-) subgroups in each BC molecular subtype (except to Luminal A) have higher LVI, PnI, and recurrence. A significant rise in LVI and PnI were observed for the HER2+/TLS- subgroup (p < 0.001). The triple negative breast cancer (TNBC)/TLS- subgroup had the highest recurrence and invasion risk which was also significantly related to tumor grade. PnI but not LVI significantly influenced recurrence in the TNBC/TLS+ subgroup (p < 0.001). TLS-stromal blood vessel interrelation was different amongst BC molecular subtypes.

CONCLUSION

BC invasion and recurrence are strongly influenced by TLS presence and stromal blood vessels, especially for HER2 and TNBC BC molecular subtypes.

Multi-Omics Analysis Reveals Intratumor Microbes as Immunomodulators in Colorectal Cancer

Recent studies indicated that intratumor microbes are an essential part of the tumor microenvironment. Here, we performed an integrated analysis of genetic, epigenetic, and intratumor microbial factors to unravel the potential remodeling mechanisms of immune-cell infiltration (ICI) and tumorigenesis of colorectal cancer (CRC). We identified the components and structure of the intratumor microbiome as primary contributors to the difference in survival between ICI subtypes. Multiple tumor-infiltrating immune cells (TIICs) and immune-related genes were associated with intratumor microbial abundance. Additionally, we found that Clostridium was enriched in CRC patients who were nonsensitive to immune checkpoint blockade (ICB) therapy. We further provided clues that the intratumor microbes might influence the response to ICB therapy by mediating TIICs, especially MAIT (mucosa-associated invariant T) cells. Finally, three ICB-related TIICs and 22 of their associated microbes showed the potential to predict the response to ICB therapy (area under the receiver operating characteristic curve [AUC] = 89%). Our findings highlight the crucial role of intratumor microbes in affecting immune-cell infiltration patterns, prognosis, and therapy response of CRC and provide insights for improving current immunotherapeutic treatment strategies and prognosis for CRC patients. IMPORTANCE Using the multi-omics data from The Cancer Genome Atlas (TCGA) colorectal cancer (CRC) cohort, we estimated the tumor microenvironment (TME) infiltration patterns of patients and unraveled the interplay of gene expression, epigenetic modification, and the intratumor microbiome. This study suggests the impact of intratumor microbes on maintaining the tumor immune microenvironment in the pathogenesis of CRC and modulating the response to immune checkpoint blockade (ICB) therapy. We identified a set of combined features, including 3 ICB-related tumor-infiltrating immune cells (TIICs) and 22 of their associated microbes, that are predictive of ICB responses.

Role of lymphocytes, macrophages and immune receptors in suppression of tumor immunity

Cancer is now the leading cause of mortality across the world. Inflammatory immune cells are functionally important in the genesis and progression of tumors, as demonstrated by their presence in human tumors. Numerous research has recently been conducted to determine if the innate and adaptive immune systems' cytotoxic cells can inhibit tumor growth and spread. Majority of cancers, when growing into identifiable tumors use multiple strategies to elude immune monitoring by lowering tumor immunity. Immunological suppression in the tumor microenvironment is achieved through interfering with antigen-presenting cells and effector T cells. Treatment of cancer requires managing both the tumor as well as tumor microenvironment (TME). Most patients will not be able to gain benefits from immunotherapy because of the immunosuppressive tumor microenvironment. The actions of many stromal myeloid and lymphoid cells are regulated to suppress tumor-specific T lymphocytes. These frequently exhibit inducible suppressive processes brought on by the same anti-tumor inflammatory response the immunotherapy aims to produce. Therefore, a deeper comprehensive understanding of how the immunosuppressive environment arises and endures is essential. Here in this chapter, we will talk about how immune cells, particularly macrophages and lymphocytes, and their receptors affect the ability of tumors to mount an immune response.

The Great Immune Escape: Understanding the Divergent Immune Response in Breast Cancer Subtypes

Breast cancer, the most common type of cancer affecting women, encompasses a collection of histologic (mainly ductal and lobular) and molecular subtypes exhibiting diverse clinical presentation, disease trajectories, treatment options, and outcomes. Immunotherapy has revolutionized treatment for some solid tumors but has shown limited promise for breast cancers. In this review, we summarize recent advances in our understanding of the complex interactions between tumor and immune cells in subtypes of breast cancer at the cellular and microenvironmental levels. We aim to provide a perspective on opportunities for future immunotherapy agents tailored to specific features of each subtype of breast cancer.

SIGNIFICANCE

Although there are currently over 200 ongoing clinical trials testing immunotherapeutics, such as immune-checkpoint blockade agents, these are largely restricted to the triple-negative and HER2+ subtypes and primarily focus on T cells. With the rapid expansion of new in vitro, in vivo, and clinical data, it is critical to identify and highlight the challenges and opportunities unique for each breast cancer subtype to drive the next generation of treatments that harness the immune system.

The Tumor Microenvironment in Tumorigenesis and Therapy Resistance Revisited

Tumorigenesis is a complex and dynamic process involving cell-cell and cell-extracellular matrix (ECM) interactions that allow tumor cell growth, drug resistance and metastasis. This review provides an updated summary of the role played by the tumor microenvironment (TME) components and hypoxia in tumorigenesis, and highlight various ways through which tumor cells reprogram normal cells into phenotypes that are pro-tumorigenic, including cancer associated- fibroblasts, -macrophages and -endothelial cells. Tumor cells secrete numerous factors leading to the transformation of a previously anti-tumorigenic environment into a pro-tumorigenic environment. Once formed, solid tumors continue to interact with various stromal cells, including local and infiltrating fibroblasts, macrophages, mesenchymal stem cells, endothelial cells, pericytes, and secreted factors and the ECM within the tumor microenvironment (TME). The TME is key to tumorigenesis, drug response and treatment outcome. Importantly, stromal cells and secreted factors can initially be anti-tumorigenic, but over time promote tumorigenesis and induce therapy resistance. To counter hypoxia, increased angiogenesis leads to the formation of new vascular networks in order to actively promote and sustain tumor growth via the supply of oxygen and nutrients, whilst removing metabolic waste. Angiogenic vascular network formation aid in tumor cell metastatic dissemination. Successful tumor treatment and novel drug development require the identification and therapeutic targeting of pro-tumorigenic components of the TME including cancer-associated- fibroblasts (CAFs) and -macrophages (CAMs), hypoxia, blocking ECM-receptor interactions, in addition to the targeting of tumor cells. The reprogramming of stromal cells and the immune response to be anti-tumorigenic is key to therapeutic success. Lastly, this review highlights potential TME- and hypoxia-centered therapies under investigation.

Activated Mast Cells Combined with NRF2 Predict Prognosis for Esophageal Cancer

Background

Esophageal cancer (EC) had the sixth-highest mortality rate of all cancers due to its poor prognosis. Immune cells and mutation genes influenced the prognosis of EC, but their combined effect on predicting EC prognosis was unknown. In this study, we comprehensively analyzed the immune cell infiltration (ICI) and mutation genes and their combined effects for predicting prognosis in EC.

Methods

The CIBERSORT and ESTIMATE algorithms were used to analyse the ICI scape based on the TCGA and GEO databases. EC tissues and pathologic sections from Huai'an, China, were used to verify the key immune cells and mutation genes and their interactions.

Results

Stromal/immune score patterns and ICI/gene had no statistical significance in overall survival (OS) (p > 0.05). The combination of ICI and tumor mutation burden (TMB) showed that the high TMB and high ICI score group had the shortest OS (p = 0.004). We recognized that the key mutation gene NRF2 was significantly different in the high/low ICI score subgroups (p = 0.002) and positivity with mast cells (MCs) (p < 0.05). Through experimental validation, we found that the MCs and activated mast cells (AC-MCs) were more infiltration in stage II/III (p = 0.032; p = 0.013) of EC patients and that NRF2 expression was upregulated in EC (p = 0.045). AC-MCs combined with NRF2 had a poor prognosis, according to survival analysis (p = 0.056) and interactive analysis (p = 0.032).

Conclusions

We presume that NRF2 combined with AC-MCs could be a marker to predict prognosis and could influence immunotherapy through regulating PD-L1 in the EC.

TSLP, IL-33, and IL-25: Not just for allergy and helminth infection

The release of cytokines from epithelial and stromal cells is critical for the initiation and maintenance of tissue immunity. Three such cytokines, thymic stromal lymphopoietin, IL-33, and IL-25, are important regulators of type 2 immune responses triggered by parasitic worms and allergens. In particular, these cytokines activate group 2 innate lymphoid cells, TH2 cells, and myeloid cells, which drive hallmarks of type 2 immunity. However, emerging data indicate that these tissue-associated cytokines are not only involved in canonical type 2 responses but are also important in the context of viral infections, cancer, and even homeostasis. Here, we provide a brief review of the roles of thymic stromal lymphopoietin, IL-33, and IL-25 in diverse immune contexts, while highlighting their relative contributions in tissue-specific responses. We also emphasize a biologically motivated framework for thinking about the integration of multiple immune signals, including the 3 featured in this review.

Interleukin 13 receptor alpha 2 (IL13Rα2): Expression, signaling pathways and therapeutic applications in cancer

Interleukin 13 receptor alpha 2 (IL13Rα2) is increasingly recognized as a relevant player in cancer invasion and metastasis. Despite being initially considered a decoy receptor for dampening the levels of interleukin 13 (IL-13) in diverse inflammatory conditions, accumulating evidences in the last decades indicate the capacity of IL13Rα2 for mediating IL-13 signaling in cancer cells. The biological reasons behind the expression of this receptor with such extremely high affinity for IL-13 in cancer cells remain unclear. Elevated expression of IL13Rα2 is commonly associated with invasion, late stage and cancer metastasis that results in poor prognosis for glioblastoma, colorectal or breast cancer, among others. The discovery of new mediators and effectors of IL13Rα2 signaling has been critical for deciphering its underlying molecular mechanisms in cancer progression. Still, many questions about the effects of inflammation, the cancer type and the tumor degree in the expression of IL13Rα2 remain largely uncharacterized. Here, we review and discuss the current status of the IL13Rα2 biology in cancer, with particular emphasis in the role of inflammation-driven expression and the regulation of different signaling pathways. As IL13Rα2 implications in cancer continue to grow exponentially, we highlight new targeted therapies recently developed for glioblastoma, colorectal cancer and other IL13Rα2-positive tumors.

Genetically diverse mouse platform to xenograft cancer cells

The lack of genetically diverse preclinical animal models in basic biology and efficacy testing has been cited as a potential cause of failure in clinical trials. We developed and characterized five diverse RAG1 null mouse strains as models that allow xenografts to grow. In these strains, we characterized the growth of breast cancer, leukemia and glioma cell lines. We found a wide range of growth characteristics that were far more dependent on strain than tumor type. For the breast cancer cell line, we characterized the spectrum of xenograft/tumor growth at structural, histological, cellular and molecular levels across each strain, and found that each strain captures unique structural components of the stroma. Furthermore, we showed that the increase in tumor-infiltrating myeloid CD45+ cells and the amount of circulating cytokine IL-6 and chemokine KC (also known as CXCL1) is associated with a higher tumor size in different strains. This resource is available to study established human xenografts, as well as difficult-to-xenograft tumors and growth of hematopoietic stems cells, and to decipher the role of myeloid cells in the development of spontaneous cancers.

The Effects of Tamoxifen on Tolerogenic Cells in Cancer

Simple Summary

Tamoxifen is a very well-known hormonal therapy used to treat breast cancer patients. It works by blocking the effects of estrogen in breast tissue by competing with estradiol (E₂) in the receptor site and binding to DNA to inhibit carcinogenesis. Moreover, it is less clarified that TAM is also involved indirectly via a Foxp3 knockout model through the CreER system to target specific immune checkpoints, especially checkpoints arising in cancer therapy. The suppressive function of tolerogenic cells is very important in the TME. Hence, in our study, we observed the effects of TAM on Tregs, in which it is involved indirectly via the CreER system. In addition, we also review the effects of TAM on other cells, which are MDSCs and DCs, that act by bridging the innate and adaptive immune systems.

Abstract

Tamoxifen (TAM) is the most prescribed selective estrogen receptor modulator (SERM) to treat hormone-receptor-positive breast cancer patients and has been used for more than 20 years. Its role as a hormone therapy is well established; however, the potential role in modulating tolerogenic cells needs to be better clarified. Infiltrating tumor-microenvironment-regulatory T cells (TME-Tregs) are important as they serve a suppressive function through the transcription factor Forkhead box P3 (Foxp3). Abundant studies have suggested that Foxp3 regulates the expression of several genes (CTLA-4, PD-1, LAG-3, TIM-3, TIGIT, TNFR2) involved in carcinogenesis to utilize its tumor suppressor function through knockout models. TAM is indirectly concomitant via the Cre/loxP system by allowing nuclear translocation of the fusion protein, excision of the floxed STOP cassette and heritable expression of encoding fluorescent protein in a cohort of cells that express Foxp3. Moreover, TAM administration in breast cancer treatment has shown its effects directly through MDSCs by the enrichment of its leukocyte populations, such as NK and NKT cells, while it impairs the differentiation and activation of DCs. However, the fundamental mechanisms of the reduction of this pool by TAM are unknown. Here, we review the vital effects of TAM on Tregs for a precise mechanistic understanding of cancer immunotherapies.

Dual Effect of Immune Cells within Tumour Microenvironment: Pro- and Anti-Tumour Effects and Their Triggers

Our body is constantly exposed to pathogens or external threats, but with the immune response that our body can develop, we can fight off and defeat possible attacks or infections. Nevertheless, sometimes this threat comes from an internal factor. Situations such as the existence of a tumour also cause our immune system (IS) to be put on alert. Indeed, the link between immunology and cancer is evident these days, with IS being used as one of the important targets for treating cancer. Our IS is able to eliminate those abnormal or damaged cells found in our body, preventing the uncontrolled proliferation of tumour cells that can lead to cancer. However, in several cases, tumour cells can escape from the IS. It has been observed that immune cells, the extracellular matrix, blood vessels, fat cells and various molecules could support tumour growth and development. Thus, the developing tumour receives structural support, irrigation and energy, among other resources, making its survival and progression possible. All these components that accompany and help the tumour to survive and to grow are called the tumour microenvironment (TME). Given the importance of its presence in the tumour development process, this review will focus on one of the components of the TME: immune cells. Immune cells can support anti-tumour immune response protecting us against tumour cells; nevertheless, they can also behave as pro-tumoural cells, thus promoting tumour progression and survival. In this review, the anti-tumour and pro-tumour immunity of several immune cells will be discussed. In addition, the TME influence on this dual effect will be also analysed.

Investigating key cell types and molecules dynamics in PyMT mice model of breast cancer through a mathematical model

The most common kind of cancer among women is breast cancer. Understanding the tumor microenvironment and the interactions between individual cells and cytokines assists us in arriving at more effective treatments. Here, we develop a data-driven mathematical model to investigate the dynamics of key cell types and cytokines involved in breast cancer development. We use time-course gene expression profiles of a mouse model to estimate the relative abundance of cells and cytokines. We then employ a least-squares optimization method to evaluate the model's parameters based on the mice data. The resulting dynamics of the cells and cytokines obtained from the optimal set of parameters exhibit a decent agreement between the data and predictions. We perform a sensitivity analysis to identify the crucial parameters of the model and then perform a local bifurcation on them. The results reveal a strong connection between adipocytes, IL6, and the cancer population, suggesting them as potential targets for therapies.

Basophils as a potential therapeutic target in cancer

Basophils, which are considered as redundant relatives of mast cells and the rarest granulocytes in peripheral circulation, have been neglected by researchers in the past decades. Previous studies have revealed their vital roles in allergic diseases and parasitic infections. Intriguingly, recent studies even reported that basophils might be associated with cancer development, as activated basophils synthesize and release a variety of cytokines and chemokines in response to cancers. However, it is still subject to debate whether basophils function as tumor-protecting or tumor-promoting components; the answer may depend on the tumor biology and the microenvironment. Herein, we reviewed the role of basophils in cancers, and highlighted some potential and promising therapeutic strategies.

The correlation between single nucleotide polymorphisms of the thymic stromal lymphopoietin receptor and breast cancer in a cohort of female patients in Saudi Arabia

The current study aimed to examine thymic stromal lymphopoietin receptor (TSLPR) genetic variation and breast cancer (BC) susceptibility in women in Saudi Arabia. Therefore, 127 blood samples from female patients diagnosed with BC and 116 blood samples from healthy female controls were studied using a genotyping assay to determine the association between three TSLPR single nucleotide polymorphisms (SNPs)-P196L, X201W, and A238V-and the risk of BC progression. In addition, gene expression was evaluated in 20 matching BC and normal tissues using immunohistochemistry. TSLPR protein levels were higher among BC patients than those with matching normal breast tissue. In addition, TSLPR SNP P196L was found to have a significant protective effect on BC progression (OR = 0.4427), although only the T allele for TSLPR P196L had this protective effect against BC progression in participants who were younger than 48 years old. In contrast, no association was found between the T allele and risk of BC in participants who were older than 48 years old, and the CT and TT genotypes were significantly associated with BC risk protection in the older group. The effects of the TT genotype and the T allele were closely associated with a decreased risk of BC in participants with estrogen receptors (ER+) and without them (ER-). Overall, the findings revealed a significant correlation between SNPs in the TSLPR genes and BC progression among women in Saudi Arabia.

Tumour Microenvironment Stress Promotes the Development of Drug Resistance

Multi-drug resistance (MDR) is a leading cause of cancer-related death, and it continues to be a major barrier to cancer treatment. The tumour microenvironment (TME) has proven to play an essential role in not only cancer progression and metastasis, but also the development of resistance to chemotherapy. Despite the significant advances in the efficacy of anti-cancer therapies, the development of drug resistance remains a major impediment to therapeutic success. This review highlights the interplay between various factors within the TME that collectively initiate or propagate MDR. The key TME-mediated mechanisms of MDR regulation that will be discussed herein include (1) altered metabolic processing and the reactive oxygen species (ROS)-hypoxia inducible factor (HIF) axis; (2) changes in stromal cells; (3) increased cancer cell survival via autophagy and failure of apoptosis; (4) altered drug delivery, uptake, or efflux and (5) the induction of a cancer stem cell (CSC) phenotype. The review also discusses thought-provoking ideas that may assist in overcoming the TME-induced MDR. We conclude that stressors from the TME and exposure to chemotherapeutic agents are strongly linked to the development of MDR in cancer cells. Therefore, there remains a vast area for potential research to further elicit the interplay between factors existing both within and outside the TME. Elucidating the mechanisms within this network is essential for developing new therapeutic strategies that are less prone to failure due to the development of resistance in cancer cells.

Microenvironmental modulation of the developing tumour: an immune-stromal dialogue

Successful establishment of a tumour relies on a cascade of interactions between cancer cells and stromal cells within an evolving microenvironment. Both immune and nonimmune cellular components are key factors in this process, and the individual players may change their role from tumour elimination to tumour promotion as the microenvironment develops. While the tumour-stroma crosstalk present in an established tumour is well-studied, aspects in the early tumour or premalignant microenvironment have received less attention. This is in part due to the challenges in studying this process in the clinic or in mouse models. Here, we review the key anti- and pro-tumour factors in the early microenvironment and discuss how understanding this process may be exploited in the clinic.

Pilot Study of Anti-Th2 Immunotherapy for the Treatment of Breast Cancer-Related Upper Extremity Lymphedema

Recent studies suggest that Th2 cells play a key role in the pathology of secondary lymphedema by elaborating cytokines such as IL4 and IL13. The aim of this study was to test the efficacy of QBX258, a monoclonal IL4/IL13 neutralizing antibody, in women with breast cancer-related lymphedema (BCRL). We enrolled nine women with unilateral stage I/II BCRL and treated them once monthly with intravenous infusions of QBX258 for 4 months. We measured limb volumes, bioimpedance, and skin tonometry, and analyzed the quality of life (QOL) using a validated lymphedema questionnaire (Upper Limb Lymphedema 27, ULL-27) before treatment, immediately after treatment, and 4 months following treatment withdrawal. We also obtained 5 mm skin biopsies from the normal and lymphedematous limbs before and after treatment. Treatment was well-tolerated; however, one patient with a history of cellulitis developed cellulitis during the trial and was excluded from further analysis. We found no differences in limb volumes or bioimpedance measurements after drug treatment. However, QBX258 treatment improved skin stiffness (p < 0.001) and improved QOL measurements (Physical p < 0.05, Social p = 0.01). These improvements returned to baseline after treatment withdrawal. Histologically, treatment decreased epidermal thickness, the number of proliferating keratinocytes, type III collagen deposition, infiltration of mast cells, and the expression of Th2-inducing cytokines in the lymphedematous skin. Our limited study suggests that immunotherapy against Th2 cytokines may improve skin changes and QOL of women with BCRL. This treatment appears to be less effective for decreasing limb volumes; however, additional studies are needed.

Psoralidin exerts anti-tumor, anti-angiogenic, and immunostimulatory activities in 4T1 tumor-bearing balb/c mice

BACKGROUND

Psoralidin as a compound of the Psoralea corylifolia seeds exhibited several anti-cancer potentials in various cancers.

MATERIALS AND METHODS

In this study, 4T1 tumor-bearing Balb/c mice were treated by intraperitoneal administration of Psoralidin, and Paraffin, as a control group to investigate anti-tumor, anti-angiogenic, and immunostimulatory activities in breast cancer. Body weight and tumor volume measurement were performed. Hematoxylin and Eosin (H&E) staining as well as immunohistochemistry for Ki-67, CD31 and VEGF markers were conducted. In addition, ELISA assay was performed for evaluating the serum level of IFN-γ and IL-4. Moreover, real time assay was performed to evaluate the expression of angiogenesis and immunostimulatory related genes.

RESULTS

There were no significant changes in the body weight of all animal groups. The anti-cancer effects of Psoralidin were significantly observed after 24 days of the last treatment, confirmed by smaller tumor volume and also H&E staining. The expression level of Ki-67, CD31 and VEGF were significantly decreased in tumor tissues of the Psoralidin-treated group in comparison with Paraffin-treated group. Moreover, there was a significant reduction in the serum level of IL-4 in tumor-bearing mice after Psoralidin treatment while the serum level of IFN-γ was significantly augmented in all groups. Moreover, the reduction in expression of VEGF-a and IL-1β was observed. Interestingly Psoralidin treatment led to expression increase of FOXp3.

CONCLUSIONS

Psoralidin shows the anti-cancer potential in an animal model of breast cancer; however, further studies are recommended to elucidate its mechanisms of action.

Tumor Microenvironment in Breast Cancer-Updates on Therapeutic Implications and Pathologic Assessment

The tumor microenvironment (TME) in breast cancer comprises local factors, cancer cells, immune cells and stromal cells of the local and distant tissues. The interaction between cancer cells and their microenvironment plays important roles in tumor proliferation, propagation and response to therapies. There is increasing research in exploring and manipulating the non-cancerous components of the TME for breast cancer treatment. As the TME is now increasingly recognized as a treatment target, its pathologic assessment has become a critical component of breast cancer management. The latest WHO classification of tumors of the breast listed stromal response pattern/fibrotic focus as a prognostic factor and includes recommendations on the assessment of tumor infiltrating lymphocytes and PD-1/PD-L1 expression, with therapeutic implications. This review dissects the TME of breast cancer, describes pathologic assessment relevant for prognostication and treatment decision, and details therapeutic options that interacts with and/or exploits the TME in breast cancer.

Human Lung-Resident Macrophages Express and Are Targets of Thymic Stromal Lymphopoietin in the Tumor Microenvironment

Thymic stromal lymphopoietin (TSLP) is a pleiotropic cytokine highly expressed by epithelial cells and several innate and adaptive immune cells. TSLP exerts its biological effects by binding to a heterodimeric complex composed of TSLP receptor (TSLPR) and IL-7Rα. In humans, there are two TSLP isoforms: the short form (sfTSLP), constitutively expressed, and the long form (lfTSLP), which is upregulated in inflammation. TSLP has been implicated in the induction and progression of several experimental and human cancers. Primary human lung macrophages (HLMs), monocyte-derived macrophages (MDMs), and peripheral blood monocytes consitutively expressed sfTSLP mRNA. Incubation of HLMs, MDMs, and monocytes with lipopolysaccharide (LPS) or IL-4, but not with IL-13, induced TSLP release from HLMs. LPS, but not IL-4 or IL-13, induced CXCL8 release from HLMs. LPS, IL-4 alone or in combination with IL-13, induced the expression of lfTSLP, but not of sfTSLP from HLMs. Preincubation of HLMs with IL-4, alone or in combination with IL-13, but not IL-13 alone, synergistically enhanced TSLP release from LPS-activated macrophages. By contrast, IL-4, alone or in combination with IL-13, inhibited LPS-induced CXCL8 release from HLMs. Immunoreactive TSLP was detected in lysates of HLMs, MDMs, and monocytes. Incubation of HLMs with TSLP induced the release of proinflammatory (TNF-α), angiogenic (VEGF-A, angiopoietin 2), and lymphangiogenic (VEGF-C) factors. TSLP, TSLPR, and IL-7Rα were expressed in intratumoral and peritumoral areas of human lung cancer. sfTSLP and lfTSLP mRNAs were differentially expressed in peritumoral and intratumoral lung cancer tissues. The TSLP system, expressed in HLMs, MDMs, and monocytes, could play a role in chronic inflammatory disorders including lung cancer.

Crosstalk between Tumor-Infiltrating Immune Cells and Cancer-Associated Fibroblasts in Tumor Growth and Immunosuppression of Breast Cancer

Signals from the tumor microenvironment (TME) have a profound influence on the maintenance and progression of cancers. Chronic inflammation and the infiltration of immune cells in breast cancer (BC) have been strongly associated with early carcinogenic events and a switch to a more immunosuppressive response. Cancer-associated fibroblasts (CAFs) are the most abundant stromal component and can modulate tumor progression according to their secretomes. The immune cells including tumor-infiltrating lymphocytes (TILs) (cytotoxic T cells (CTLs), regulatory T cells (Tregs), and helper T cell (Th)), monocyte-infiltrating cells (MICs), myeloid-derived suppressor cells (MDSCs), mast cells (MCs), and natural killer cells (NKs) play an important part in the immunological balance, fluctuating TME between protumoral and antitumoral responses. In this review article, we have summarized the impact of these immunological players together with CAF secreted substances in driving BC progression. We explain the crosstalk of CAFs and tumor-infiltrating immune cells suppressing antitumor response in BC, proposing these cellular entities as predictive markers of poor prognosis. CAF-tumor-infiltrating immune cell interaction is suggested as an alternative therapeutic strategy to regulate the immunosuppressive microenvironment in BC.

Metabolic Interdependency of Th2 Cell-Mediated Type 2 Immunity and the Tumor Microenvironment

The function of T cells is critically dependent on their ability to generate metabolic building blocks to fulfil energy demands for proliferation and consecutive differentiation into various T helper (Th) cells. Th cells then have to adapt their metabolism to specific microenvironments within different organs during physiological and pathological immune responses. In this context, Th2 cells mediate immunity to parasites and are involved in the pathogenesis of allergic diseases including asthma, while CD8+ T cells and Th1 cells mediate immunity to viruses and tumors. Importantly, recent studies have investigated the metabolism of Th2 cells in more detail, while others have studied the influence of Th2 cell-mediated type 2 immunity on the tumor microenvironment (TME) and on tumor progression. We here review recent findings on the metabolism of Th2 cells and discuss how Th2 cells contribute to antitumor immunity. Combining the evidence from both types of studies, we provide here for the first time a perspective on how the energy metabolism of Th2 cells and the TME interact. Finally, we elaborate how a more detailed understanding of the unique metabolic interdependency between Th2 cells and the TME could reveal novel avenues for the development of immunotherapies in treating cancer.

The Role of Tumor Necrosis Factor in Manipulating the Immunological Response of Tumor Microenvironment

The tumor microenvironment (TME) is an intricate system within solid neoplasms. In this review, we aim to provide an updated insight into the TME with a focus on the effects of tumor necrosis factor-α (TNF-α) on its various components and the use of TNF-α to improve the efficiency of drug delivery. The TME comprises the supporting structure of the tumor, such as its extracellular matrix and vasculature. In addition to cancer cells and cancer stem cells, the TME contains various other cell types, including pericytes, tumor-associated fibroblasts, smooth muscle cells, and immune cells. These cells produce signaling molecules such as growth factors, cytokines, hormones, and extracellular matrix proteins. This review summarizes the intricate balance between pro-oncogenic and tumor-suppressive functions that various non-tumor cells within the TME exert. We focused on the interaction between tumor cells and immune cells in the TME that plays an essential role in regulating the immune response, tumorigenesis, invasion, and metastasis. The multifunctional cytokine, TNF-α, plays essential roles in diverse cellular events within the TME. The uses of TNF-α in cancer treatment and to facilitate cancer drug delivery are discussed. The effects of TNF-α on tumor neovasculature and tumor interstitial fluid pressure that improve treatment efficacy are summarized.

Low KRT15 expression is associated with poor prognosis in patients with breast invasive carcinoma

Although keratin 15 (KRT15) has been indicated to be overexpressed in several types of tumor, its role in breast invasive carcinoma (BRCA) has so far remained elusive. The aim of the present study was to explore KRT15 expression in BRCA based on data obtained from The Cancer Genome Atlas and The Genotype-Tissue Expression. KRT15 expression was compared using a Wilcoxon rank-sum test. Functional enrichment analysis was performed to reveal the biological roles and pathways of KRT15. The association between KRT15 expression and immune-cell infiltration was evaluated via single-sample gene set enrichment analysis (ssGSEA). To investigate the relationship between clinicopathological features and KRT15 expression, the prognostic value of KRT15 and other clinical factors was evaluated using Cox regression analysis and Kaplan-Meier (KM) plots. Subgroup prognostic analysis was also performed using forest plots and KM curves. Finally, a tissue microarray was used to assess KRT15 expression in BRCA tissues. KRT15 expression was significantly lower in BRCA tissues compared with that in normal tissues. Functional enrichment analysis suggested that KRT15-related genes were primarily enriched in the transmembrane transporter complex, cornification and ligand-receptor interactions. Increased KRT15 was associated with several tumor-suppressive pathways. ssGSEA revealed that high KRT15 expression was significantly associated with natural killer-cell, B-cell and mast-cell infiltration. Significant associations were observed between low KRT15 expression and advanced stage clinicopathological factors, as well as unfavorable overall survival (OS) and disease-specific survival. Multivariate Cox regression analysis suggested that KRT15 was an independent prognostic factor for OS (P=0.039; hazard ratio, 0.590; 95% CI, 0.358-0.974). Subgroup prognostic analysis demonstrated that low KRT15 was a reliable predictor of poor OS. Immunohistochemistry of a tissue microarray indicated that positive KRT15 expression rates were significantly higher in normal tissues compared with those in the BRCA tissues. In conclusion, low KRT15 expression was significantly associated with poor prognosis in patients with BRCA. Thus, KRT15 may serve an important role in BRCA progression and may be used as a promising prognostic marker for diagnostic and prognostic analyses in patients with BRCA.

Dynamic roles of inflammasomes in inflammatory tumor microenvironment

The inflammatory tumor microenvironment has been known to be closely connected to all stages of cancer development, including initiation, promotion, and progression. Systemic inflammation in the tumor microenvironment is increasingly being recognized as an important prognostic marker in cancer patients. Inflammasomes are master regulators in the first line of host defense for the initiation of innate immune responses. Inflammasomes sense pathogen-associated molecular patterns and damage-associated molecular patterns, following recruitment of immune cells into infection sites. Therefore, dysregulated expression/activation of inflammasomes is implicated in pathogenesis of diverse inflammatory disorders. Recent studies have demonstrated that inflammasomes play a vital role in regulating the development and progression of cancer. This review focuses on fate-determining roles of the inflammasomes and the principal downstream effector cytokine, IL-1β, in the tumor microenvironment.

Antitumor effects of Auraptene in 4T1 tumor-bearing Balb/c mice

OBJECTIVES

Breast cancer is a common malignant tumor in women with limited treatment options and multiple side effects. Today, the anti-cancer properties of natural compounds have attracted widespread attention from researchers worldwide.

METHODS

In this study, we treated 4T1 tumor-bearing Balb/c mice with intraperitoneal injection of Auraptene, paraffin oil, and saline as two control groups. Body weight and tumor volume were measured before and after treatment. Hematoxylin and eosin (H & E) staining and immunohistochemistry of Ki-67 were used as markers of proliferation. In addition, ELISA assays were performed to assess serum IFN-γ and IL-4 levels.

RESULTS

There was no significant change in body weight in all animal groups before and after treatment. 10 days after the last treatment, Auraptene showed its anti-cancer effect, which was confirmed by the smaller tumor volume and H & E staining. In addition, Ki-67 expression levels were significantly reduced in tumor samples from the Auraptene-treated group compared to the paraffin oil and saline-treated groups. In addition, in tumor-bearing and normal mice receiving Auraptene treatment, IL-4 serum production levels were reduced, while serum levels of IFN-γ were significantly up-regulated in tumor-bearing mice after Auraptene treatment.

CONCLUSIONS

In the case of inhibition of tumor volume and Ki-67 proliferation markers, Auraptene can effectively inhibit tumor growth in breast cancer animal models. In addition, it might increases Th1 and CD8 + T cell responses after reducing IL-4 serum levels and IFN-γ upregulation, respectively. However, further research is needed to clarify its mechanism of action.

Building the Next Generation of Humanized Hemato-Lymphoid System Mice

Since the late 1980s, mice have been repopulated with human hematopoietic cells to study the fundamental biology of human hematopoiesis and immunity, as well as a broad range of human diseases in vivo. Multiple mouse recipient strains have been developed and protocols optimized to efficiently generate these “humanized” mice. Here, we review three guiding principles that have been applied to the development of the currently available models: (1) establishing tolerance of the mouse host for the human graft; (2) opening hematopoietic niches so that they can be occupied by human cells; and (3) providing necessary support for human hematopoiesis. We then discuss four remaining challenges: (1) human hematopoietic lineages that poorly develop in mice; (2) limited antigen-specific adaptive immunity; (3) absent tolerance of the human immune system for its mouse host; and (4) sub-functional interactions between human immune effectors and target mouse tissues. While major advances are still needed, the current models can already be used to answer specific, clinically-relevant questions and hopefully inform the development of new, life-saving therapies.

STATing the importance of immune modulation by platinum chemotherapeutics

Platinum-based anticancer drugs enhance the immunostimulatory potential of DCs and decrease the immunosuppressive capacity of tumor cells. This immunomodulatory ability is based on the inhibition of STAT6-mediated expression of co-inhibitory molecule PD-L2 and opens up the possibility of using these drugs in combination with other immunostimulatory compounds.

The tumor-promoting effects of the adaptive immune system: a cause of hyperprogressive disease in cancer?

Adaptive antitumor immune responses, either cellular or humoral, aim at eliminating tumor cells expressing the cognate antigens. There are some instances, however, where these same immune responses have tumor-promoting effects. These effects can lead to the expansion of antigen-negative tumor cells, tumor cell proliferation and tumor growth, metastatic dissemination, resistance to antitumor therapy and apoptotic stimuli, acquisition of tumor-initiating potential and activation of various forms of survival mechanisms. We describe the basic mechanisms that underlie tumor-promoting adaptive immune responses and try to identify the variables that induce the switching of a tumor-inhibitory, cellular or humoral immune response, into a tumor-promoting one. We suggest that tumor-promoting adaptive immune responses may be at the origin of at least a fraction of hyperprogressive diseases (HPD) that are observed in cancer patients during therapy with immune checkpoint inhibitors (ICI) and, less frequently, with single-agent chemotherapy. We also propose the use of non-invasive biomarkers allowing to predict which patients may undergo HPD during ICI and other forms of antitumor therapy. Eventually, we suggest possibilities of therapeutic intervention allowing to inhibit tumor-promoting adaptive immune responses.

[The ambiguous role of the inflammatory micromilieu in solid tumors]

BACKGROUND

Besides host defense against infections, the main function of the immune system is to eliminate tumor cells. Therefore, nearly, all solid tumors have a heterogeneous fibro-inflammatory microenvironment, which consists of myofibroblastic cells, extracellular matrix components, and infiltrates from various types of immune cell. In particular, pancreatic ductal adenocarcinoma is a prototype of a tumor with a pronounced inflammatory microenvironment, in which the majority of the tumor mass consists of nonneoplastic stromal and immune cells. Our own data and data from the literature indicate a protective role of tumor-infiltrating T cells for the host. On the other hand, we were able to show that a defined T cell subpopulation paradoxically promotes the progression of the tumor. Our investigations now focus on these cells, known as "Th17," in the tumor microenvironment.

OBJECTIVES

To elucidate the mechanisms of the infiltrated immune cells and their mediators in the tumor microenvironment.

MATERIALS AND METHODS

Human pancreatic cancer tissue was used for (immune) histological staining and morphometric analysis and the results were correlated with clinical parameters and with diffusion-weighted magnetic resonance imaging images. The molecular mechanisms were analyzed in cell culture approaches using human tumor cells and human immune cells. With molecular biological methods and functional assays cell growth, invasion and colony formation were assessed. The in vivo correlation of the results and functional interventions were tested in murine and avian (xenograft) models.

RESULTS AND CONCLUSION

Tumor-infiltrating immune cells of type Th17 and their mediators promoted the progression of the tumor depending on density, activation status, and cytokine profile. On molecular level, we identified a Th17-mediated increase of tumor cell migration and invasion, an increased neoangiogenesis, as well as a reorganization of the tumor stroma and microarchitecture. The data show that the progression of pancreatic cancer, depends on the status of activation and the cytokine profile of the infiltrated T cells.

A Holistic Perspective: Exosomes Shuttle between Nerves and Immune Cells in the Tumor Microenvironment

One of the limitations of cancer research has been the restricted focus on tumor cells and the omission of other non-malignant cells that are constitutive elements of this systemic disease. Current research is focused on the bidirectional communication between tumor cells and other components of the tumor microenvironment (TME), such as immune and endothelial cells, and nerves. A major success of this bidirectional approach has been the development of immunotherapy. Recently, a more complex landscape involving a multi-lateral communication between the non-malignant components of the TME started to emerge. A prime example is the interplay between immune and endothelial cells, which led to the approval of anti-vascular endothelial growth factor-therapy combined with immune checkpoint inhibitors and classical chemotherapy in non-small cell lung cancer. Hence, a paradigm shift approach is to characterize the crosstalk between different non-malignant components of the TME and understand their role in tumorigenesis. In this perspective, we discuss the interplay between nerves and immune cells within the TME. In particular, we focus on exosomes and microRNAs as a systemic, rapid and dynamic communication channel between tumor cells, nerves and immune cells contributing to cancer progression. Finally, we discuss how combinatorial therapies blocking this tumorigenic cross-talk could lead to improved outcomes for cancer patients.

Immune microenvironment in different molecular subtypes of ductal breast carcinoma

PURPOSE

Ductal breast carcinoma as a heterogeneous disease has different molecular subtypes associated with clinical prognosis and patients' survival. The role of immune system as a consistent part of the tumor microenvironment (TME) has been documented in progression of ductal breast carcinoma. Here, we aimed to describe the important immune cells and the immune system-associated molecules in Ductal Carcinoma In situ (DCIS) and Invasive Ductal Carcinoma (IDC) with special emphasis on their associations with different molecular subtypes and patients' prognosis.

RESULTS

The immune cells have a dual role in breast cancer (BC) microenvironment depending on the molecular subtype or tumor grade. These cells with different frequencies are present in the TME of DCIS and IDC. The presence of regulatory cells including Tregs, MDSC, Th2, Th17, M2 macrophages, HLADR^- T cells, and Tγδ cells is related to more immunosuppressive microenvironment, especially in ER^- and TN subtypes. In contrast, NK cells, CTL, Th, and Tfh cells are associated to the anti-tumor activity. These cells are higher in ER⁺ BC, although in other subtypes such as TN or HER2⁺ are associated with a favorable prognosis.

CONCLUSION

Determining the specific immune response in each subtype could be helpful in estimating the possible behavior of the tumor cells in TME. It is important to realize that different frequencies of immune cells in BC environment likely determine the patients' prognosis and their survival in each subtype. Therefore, elucidation of the distinct immune players in TME would be helpful toward developing targeted therapies in each subtype.

Thymic Stromal Lymphopoietin and Cancer: Th2-Dependent and -Independent Mechanisms

The thymic stromal lymphopoietin (TSLP) is an IL-7-like cytokine originally cloned from a murine thymic stromal cell line, and subsequently a human homolog was identified using database search methods. Human TSLP is mostly expressed in epithelial cells, among which are keratinocytes as well as stromal cells such as fibroblasts and immune cells. Human TSLP was first described to activate myeloid dendritic cells, which prime naïve T helper cells to produce high concentrations of Th2 cytokines, thus representing a key cytokine in triggering dendritic cells-mediated allergic Th2 inflammation. TSLP and/or its receptor has been shown to be expressed in several tumor types, where TSLP expression is associated with functional activities that can be associated or not with the induction of a Th2-prone tumor microenvironment, i.e., Th2-dependent and Th2-independent mechanisms. These mechanisms involve tissue- and immune cell target-dependent tumor-promoting or tumor-suppressive functions in different or even the same tumor type. Here we report and discuss the Th2-dependent and Th2-independent roles of TSLP in cancer and possible therapeutic targeting.

The Role of the Tumor Microenvironment in Developing Successful Therapeutic and Secondary Prophylactic Breast Cancer Vaccines

Breast cancer affects roughly one in eight women over their lifetime and is a leading cause of cancer-related death in women. While outcomes have improved in recent years, prognosis remains poor for patients who present with either disseminated disease or aggressive molecular subtypes. Cancer immunotherapy has revolutionized the treatment of several cancers, with therapeutic vaccines aiming to direct the cytotoxic immune program against tumor cells showing particular promise. However, these results have yet to translate to breast cancer, which remains largely refractory from such approaches. Recent evidence suggests that the breast tumor microenvironment (TME) is an important and long understudied barrier to the efficacy of therapeutic vaccines. Through an improved understanding of the complex and biologically diverse breast TME, it may be possible to advance new combination strategies to render breast carcinomas sensitive to the effects of therapeutic vaccines. Here, we discuss past and present efforts to advance therapeutic vaccines in the treatment of breast cancer, the molecular mechanisms through which the TME contributes to the failure of such approaches, as well as the potential means through which these can be overcome.

Mendelian randomization analyses of genetically predicted circulating levels of cytokines with risk of breast cancer

To determine whether genetically predicted circulating levels of cytokines are associated with risk of overall breast cancer (BC), estrogen receptor (ER)-positive and ER-negative BC, we conducted two-sample MR analyses using data from the most comprehensive genome-wide association studies (GWAS) on cytokines in 8293 Finnish participants and the largest BC GWAS from the Breast Cancer Association Consortium (BCAC) with totally 122,977 BC cases and 105,974 healthy controls. We systematically screened 41 cytokines (of which 24 cytokines have available instruments) and identified that genetically predicted circulating levels (1-SD increase) of MCP1 (OR: 1.08; 95% CIs: 1.03–1.12; P value: 3.55 × 10⁻⁴), MIP1b (OR: 1.02; 95% CIs: 1.01–1.04; P value: 2.70 × 10⁻³) and IL13 (OR: 1.06; 95% CIs: 1.03–1.10; P value: 3.33 × 10⁻⁴) were significantly associated with increased risk of overall BC, as well as ER-positive BC. In addition, higher levels of MIP1b and IL13 were also significantly associated with increased risk of ER-negative BC. These findings suggest the crucial role of cytokines in BC carcinogenesis and potential of targeting specific inflammatory cytokines for BC prevention.

Spontaneous and Induced Animal Models for Cancer Research

Considering the complexity of the current framework in oncology, the relevance of animal models in biomedical research is critical in light of the capacity to produce valuable data with clinical translation. The laboratory mouse is the most common animal model used in cancer research due to its high adaptation to different environments, genetic variability, and physiological similarities with humans. Beginning with spontaneous mutations arising in mice colonies that allow for pursuing studies of specific pathological conditions, this area of in vivo research has significantly evolved, now capable of generating humanized mice models encompassing the human immune system in biological correlation with human tumor xenografts. Moreover, the era of genetic engineering, especially of the hijacking CRISPR/Cas9 technique, offers powerful tools in designing and developing various mouse strains. Within this article, we will cover the principal mouse models used in oncology research, beginning with behavioral science of animals vs. humans, and continuing on with genetically engineered mice, microsurgical-induced cancer models, and avatar mouse models for personalized cancer therapy. Moreover, the area of spontaneous large animal models for cancer research will be briefly presented.

Tumors induce de novo steroid biosynthesis in T cells to evade immunity

Tumors subvert immune cell function to evade immune responses, yet the complex mechanisms driving immune evasion remain poorly understood. Here we show that tumors induce de novo steroidogenesis in T lymphocytes to evade anti-tumor immunity. Using a transgenic steroidogenesis-reporter mouse line we identify and characterize de novo steroidogenic immune cells, defining the global gene expression identity of these steroid-producing immune cells and gene regulatory networks by using single-cell transcriptomics. Genetic ablation of T cell steroidogenesis restricts primary tumor growth and metastatic dissemination in mouse models. Steroidogenic T cells dysregulate anti-tumor immunity, and inhibition of the steroidogenesis pathway is sufficient to restore anti-tumor immunity. This study demonstrates T cell de novo steroidogenesis as a mechanism of anti-tumor immunosuppression and a potential druggable target.

Development and function of human dendritic cells in humanized mice models

Dendritic cells (DCs) are sentinel cells of the immune system arising from hematopoietic stem cells. DCs play a key role in the regulation of both adaptive and innate lymphocyte responses. As such, experimental models enabling a thorough analysis of human DCs development and function are needed. Humanized mice models (termed collectively as HIS mice, or human immune system mice models) provide unique opportunities to model human hematopoiesis and tackle the function of human immune cell types in vivo. Here, we review experimental approaches enabling to recapitulate the ontogeny of DC subsets in HIS mice and discuss studies addressing the biology of human DC subsets implementing HIS mice models.

Tumor-infiltrating regulatory T cells, CD8/Treg ratio, and cancer stem cells are correlated with lymph node metastasis in patients with early breast cancer

BACKGROUND

Tumor-infiltrating lymphocytes are an important component of the tumor microenvironment (TME) in breast cancer. They have been linked with tumor pathogenesis in advanced stages. However, little is known about their contribution in early phases. In this study, we analyzed the infiltration of leukocytes and cancer stem cells (CSC) in tumors from patients with early breast cancer.

METHODS

Samples of blood and tumor tissue from 30 patients with breast cancer were collected, and the number of dendritic cells (DC), T cells, and CSC were analyzed by flow cytometry.

RESULTS

Tumor-infiltrating CD4 and CD8 T cells expressed higher levels of cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) compared with peripheral T cells. Regulatory T cells (Treg) were enriched in tumors and overexpressed glucocorticoid-induced TNFR-related protein and CTLA-4. Tumor Treg had a positive correlation with the amount of myeloid DC (mDC) and disease progression. The CD8/Treg ratio was associated with lymph node metastasis and tumor stages. The main subset of DC in early breast tumors was mDC, while plasmacytoid DC were almost absent. CSC were present in most tumors with higher frequencies in patients with lymph node metastasis. CSC were also associated with the amount of tumor-infiltrating Treg.

CONCLUSION

Early breast cancer has an inflammatory milieu characterized by mDC, Treg, and CSC infiltration. The frequencies of Treg, CSC and CD8/Treg ratio were associated with disease progression. The composition of leukocytes and the presence of CSC in early breast tumors should be considered for the development of new therapeutic approaches.