Tumor-Stroma-Inflammation Networks Promote Pro-metastatic Chemokines and Aggressiveness Characteristics in Triple-Negative Breast Cancer

Targeted immunotherapy against distinct cancer-associated fibroblasts overcomes treatment resistance in refractory HER2+ breast tumors

About 50% of human epidermal growth factor receptor 2 (HER2)+ breast cancer patients do not benefit from HER2-targeted therapy and almost 20% of them relapse after treatment. Here, we conduct a detailed analysis of two independent cohorts of HER2+ breast cancer patients treated with trastuzumab to elucidate the mechanisms of resistance to anti-HER2 monoclonal antibodies. In addition, we develop a fully humanized immunocompetent model of HER2+ breast cancer recapitulating ex vivo the biological processes that associate with patients’ response to treatment. Thanks to these two approaches, we uncover a population of TGF-beta-activated cancer-associated fibroblasts (CAF) specific from tumors resistant to therapy. The presence of this cellular subset related to previously described myofibroblastic (CAF-S1) and podoplanin+ CAF subtypes in breast cancer associates with low IL2 activity. Correspondingly, we find that stroma-targeted stimulation of IL2 pathway in unresponsive tumors restores trastuzumab anti-cancer efficiency. Overall, our study underscores the therapeutic potential of exploiting the tumor microenvironment to identify and overcome mechanisms of resistance to anti-cancer treatment.

A substantial proportion of HER2+ breast cancer patients do not benefit from HER2-targeted therapy. Here, the authors identify a population of cancer-associated fibroblasts involved in the suppression of trastuzumab-induced ADCC that can be pharmacologically targeted to raise treatment effectiveness in unresponsive tumors.

Mesenchymal stem/stromal cells in breast cancer development and management

Mesenchymal stem/stromal cells (MSCs) encompass a heterogeneous population of fibroblastic progenitor cells that reside in multiple tissues around the body. They are endowed with capacities to differentiate into multiple connective tissue lineages, including chondrocytes, adipocytes, and osteoblasts, and are thought to function as trophic cells recruited to sites of injury and inflammation where they contribute to tissue regeneration. In keeping with these roles, MSCs also to home to sites of breast tumorigenesis, akin to their migration to wounds, and participate in tumor stroma formation. Mounting evidence over the past two decades has described the critical regulatory roles for tumor-associated MSCs in various aspects of breast tumor pathogenesis, be it tumor initiation, growth, angiogenesis, tumor microenvironment formation, immune evasion, cancer cell migration, invasion, survival, therapeutic resistance, dissemination, and metastatic colonization. In this review, we present a brief summary of the role of MSCs in breast tumor development and progression, highlight some of the molecular frameworks underlying their pro-malignant contributions, and present evidence of their promising utility in breast cancer therapy.

Phenanthroindolizidine Alkaloids Isolated from Tylophora ovata as Potent Inhibitors of Inflammation, Spheroid Growth, and Invasion of Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC), representing the most aggressive form of breast cancer with currently no targeted therapy available, is characterized by an inflammatory and hypoxic tumor microenvironment. To date, a broad spectrum of anti-tumor activities has been reported for phenanthroindolizidine alkaloids (PAs), however, their mode of action in TNBC remains elusive. Thus, we investigated six naturally occurring PAs extracted from the plant Tylophora ovata: O-methyltylophorinidine (1) and its five derivatives tylophorinidine (2), tylophoridicine E (3), 2-demethoxytylophorine (4), tylophoridicine D (5), and anhydrodehydrotylophorinidine (6). In comparison to natural (1) and for more-in depth studies, we also utilized a sample of synthetic O-methyltylophorinidine (1s). Our results indicate a remarkably effective blockade of nuclear factor kappa B (NFκB) within 2 h for compounds (1) and (1s) (IC50 = 17.1 ± 2.0 nM and 3.3 ± 0.2 nM) that is different from its effect on cell viability within 24 h (IC50 = 13.6 ± 0.4 nM and 4.2 ± 1 nM). Furthermore, NFκB inhibition data for the additional five analogues indicate a structure–activity relationship (SAR). Mechanistically, NFκB is significantly blocked through the stabilization of its inhibitor protein kappa B alpha (IκBα) under normoxic as well as hypoxic conditions. To better mimic the TNBC microenvironment in vitro, we established a 3D co-culture by combining the human TNBC cell line MDA-MB-231 with primary murine cancer-associated fibroblasts (CAF) and type I collagen. Compound (1) demonstrates superiority against the therapeutic gold standard paclitaxel by diminishing spheroid growth by 40% at 100 nM. The anti-proliferative effect of (1s) is distinct from paclitaxel in that it arrests the cell cycle at the G0/G1 state, thereby mediating a time-dependent delay in cell cycle progression. Furthermore, (1s) inhibited invasion of TNBC monoculture spheroids into a matrigel®-based environment at 10 nM. In conclusion, PAs serve as promising agents with presumably multiple target sites to combat inflammatory and hypoxia-driven cancer, such as TNBC, with a different mode of action than the currently applied chemotherapeutic drugs.

Inflammation-Driven Regulation of PD-L1 and PD-L2, and Their Cross-Interactions with Protective Soluble TNFα Receptors in Human Triple-Negative Breast Cancer

Pro-inflammatory cytokines play key roles in elevating cancer progression in triple-negative breast cancer (TNBC). We demonstrate that specific combinations between TNFα, IL-1β and IFNγ up-regulated the proportion of human TNBC cells co-expressing the inhibitory immune checkpoints PD-L1 and PD-L2: TNFα + IL-1β in MDA-MB-231 cells and IFNγ + IL-1β in BT-549 cells; in the latter cells, the process depended entirely on STAT1 activation, with no involvement of p65 (CRISPR-Cas9 experiments). Highly significant associations between the pro-inflammatory cytokines and PD-L1/PD-L2 expression were revealed in the TCGA dataset of basal-like breast cancer patients. In parallel, we found that the pro-inflammatory cytokines regulated the expression of the soluble receptors of tumor necrosis factor α (TNFα), namely sTNFR1 and sTNFR2; moreover, we revealed that sTNFR1 and sTNFR2 serve as anti-metastatic and protective factors in TNBC, reducing the TNFα-induced production of inflammatory pro-metastatic chemokines (CXCL8, CXCL1, CCL5) by TNBC cells. Importantly, we found that in the context of inflammatory stimulation and also without exposure to pro-inflammatory cytokines, elevated levels of PD-L1 have down-regulated the production of anti-tumor sTNFR1 and sTNFR2. These findings suggest that in addition to its immune-suppressive activities, PD-L1 may promote disease course in TNBC by inhibiting the protective effects of sTNFR1 and sTNFR2.

Unusual Association of NF-κB Components in Tumor-Associated Macrophages (TAMs) Promotes HSPG2-Mediated Immune-Escaping Mechanism in Breast Cancer

The cellular heterogeneity of the tumor environment of breast cancer (BC) is extremely complex and includes different actors such as neoplastic, stromal, and immunosuppressive cells, which contribute to the chemical and mechanical modification of the environment surrounding the tumor-exasperating immune-escaping mechanisms. In addition to molecular signals that make the tumor microenvironment (TME) unacceptable for the penetrance of the immune system, the physical properties of tumoral extracellular matrix (tECM) also have carved out a fundamental role in the processes of the protection of the tumor niche. Tumor-associated macrophages (TAMs), with an M2 immunosuppressive phenotype, are important determinants for the establishment of a tumor phenotype excluded from T cells. NF-κB transcription factors orchestrate innate immunity and represent the common thread between inflammation and cancer. Many studies have focused on canonical activation of NF-κB; however, activation of non-canonical signaling predicts poor survival and resistance to therapy. In this scenario, we demonstrated the existence of an unusual association of NF-κB components in TAMs that determines the deposition of HSPG2 that affects the stiffness of tECM. These results highlight a new mechanism counterbalanced between physical factors and a new perspective of mechano-pathology to be targeted to counteract immune evasion in BC.

A novel inflammation‑associated prognostic signature for clear cell renal cell carcinoma

Clear cell renal cell carcinoma (ccRCC) are typically situated in a complex inflammatory and immune microenvironment, which has been reported to contribute to the unfavorable prognosis of patients with ccRCC. There would be beneficial clinical implications for elucidating the roles of its molecular characteristics in the inflammatory microenvironment. This is because it would facilitate the development of reliable biomarkers for pre-stratification prior to the designation of individualized treatment strategies. In the present study, RNA-sequencing data from 607 patients were retrospectively analyzed to elucidate the profile of inflammatory molecules. Based on this, an inflammatory prognostic signature (IPS) was developed and further validated using clinical ccRCC samples. Subsequently, the associated mechanisms in terms of the immune microenvironment and molecular pathways were then investigated. This proposed IPS was found to exhibit superior accuracy compared with the criterion of a good prognostic model for the prediction of patient prognosis from ccRCC [area under the receiver operating characteristic curve (AUC)=0.811] in addition to being an independent factor for prognostic risk stratification [hazard ratio: 11.73 (95% CI, 26.98-5.10); log-rank test, P<0.001]. Pathologically, ccRCC cells identified as high-risk according to their IPS presented with a more malignant tumor structure, including voluminous eosinophilic cytoplasm, acinar/lamellar/tubular growth patterns and atypic nuclei. High-risk ccRCC also exhibited higher infiltration levels by four types of immune cells, including T regulatory cells, but lower infiltration levels by mast cells. Pathways associated with immune-inflammation interaction, including the IL-17 pathway, were found to be upregulated in IPS-identified high-risk ccRCC. Furthermore, by combining the IPS with clinical factors, an integrated prognostic index was developed and validated for increasing the accuracy of patient risk-stratification for ccRCC (AUC=0.911). In conclusion, the complex regulatory mechanisms and molecular characteristics involved in ccRCC-inflammation interaction, coupled with their prognostic potential, were systematically elucidated in the present study. This may have important implications in furthering the understanding into the molecular mechanisms underlying this ccRCC-inflammation interaction, which can in turn be exploited for identifying high-risk patients with ccRCC prior to designing their clinical treatment strategy.

Fibronectin Functions as a Selective Agonist for Distinct Toll-like Receptors in Triple-Negative Breast Cancer

The microenvironment of tumors is characterized by structural changes in the fibronectin matrix, which include increased deposition of the EDA isoform of fibronectin and the unfolding of the fibronectin Type III domains. The impact of these structural changes on tumor progression is not well understood. The fibronectin EDA (FnEDA) domain and the partially unfolded first Type III domain of fibronectin (FnIII-1c) have been identified as endogenous damage-associated molecular pattern molecules (DAMPs), which induce innate immune responses by serving as agonists for Toll-Like Receptors (TLRs). Using two triple-negative breast cancer (TNBC) cell lines MDA-MB-468 and MDA-MB-231, we show that FnEDA and FnIII-1c induce the pro-tumorigenic cytokine, IL-8, by serving as agonists for TLR5 and TLR2, the canonical receptors for bacterial flagellin and lipoprotein, respectively. We also find that FnIII-1c is not recognized by MDA-MB-468 cells but is recognized by MDA-MB-231 cells, suggesting a cell type rather than ligand specific utilization of TLRs. As IL-8 plays a major role in the progression of TNBC, these studies suggest that tumor-induced structural changes in the fibronectin matrix promote an inflammatory microenvironment conducive to metastatic progression.

Triple-negative breast cancer drug resistance, durable efficacy, and cure: How advanced biological insights and emerging drug modalities could transform progress

INTRODUCTION

Triple-negative breast cancer (TNBC) is a heterogeneous disease characterized by the lack of estrogen receptor (ER), progesterone receptor (PR) and epidermal growth factor receptor 2 (HER2) and often associated with poor survival outcomes. The backbone of current treatments for TNBC relies on chemotherapy; however, resistance to cytotoxic agents is a commonly encountered hurdle to overcome.

AREAS COVERED

: Current understanding on the mechanisms involved in TNBC chemoresistance is evaluated and novel potential actionable targets and recently explored modalities for carrying and delivering chemotherapeutics are highlighted.

EXPERT OPINION

: A comprehensive identification of both genomic and functional TNBC signatures is required for a more definite categorization of the patients in order to prevent insensitivity to chemotherapy and therefore realize the full potential of precision-medicine approaches. In this scenario, cell-line-derived xenografts (CDX), patient-derived xenografts (PDX), patient-derived orthotopic xenografts (PDOX) and patient-derived organoids (PDO) are indispensable experimental models for evaluating the efficacy of drug candidates and predicting the therapeutic response. The combination of increasingly sensitive "omics" technologies, computational algorithms and innovative drug modalities may accelerate the successful translation of novel candidate TNBC targets from basic research to clinical settings, thus contributing to reach optimal clinical output, with lower side effects and reduced resistance.

A comprehensive bioinformatics analysis to identify potential prognostic biomarkers among CC and CXC chemokines in breast cancer

Breast cancer (BC) is a major human health problem due to its increasing incidence and mortality rate. CC and CXC chemokines are associated with tumorigenesis and the progression of many cancers. Since the prognostic values of CC and CXC families' expression in various types of cancers are becoming increasingly evident, we aimed to conduct a comprehensive bioinformatics analysis elucidating the prognostic values of the CC and CXC families in BC. Therefore, TCGA, UALCAN, Kaplan–Meier plotter, bc-GenExMiner, cBioPortal, STRING, Enrichr, and TIMER were utilized for analysis. We found that high levels of CCL4/5/14/19/21/22 were associated with better OS and RFS, while elevated expression of CCL24 was correlated with shorter OS in BC patients. Also, high levels of CXCL9/13 indicated longer OS, and enhanced expression of CXCL12/14 was linked with better OS and RFS in BC patients. Meanwhile, increased transcription levels of CXCL8 were associated with worse OS and RFS in BC patients. In addition, our results showed that CCL5, CCL8, CCL14, CCL20, CCL27, CXCL4, and CXCL14 were notably correlated with the clinical outcomes of BC patients. Our findings provide a new point of view that may help the clinical application of CC and CXC chemokines as prognostic biomarkers in BC.

Origin, activation and heterogeneity of fibroblasts associated with pancreas and breast cancers

Pancreas and breast cancers both contain abundant stromal components within the tumor tissues. A prominent cell type within the stroma is cancer-associated fibroblasts (CAFs). CAFs play critical and complex roles establishing the tumor microenvironment to either promote or prevent tumor progression. Recently, complex genetic models and single cell-based techniques have provided emerging insights on the precise functions and cellular heterogeneity of CAFs. The transformation of normal fibroblasts into CAFs is a key event during tumor initiation and progression. Such coordination between tumor cells and fibroblasts plays an important role in cancer development. Reprograming fibroblasts is currently being explored for therapeutic benefits. In this review, we will discuss recent literature shedding light on the tissues of origin, activation mechanisms, and heterogeneity of CAFs comparing pancreas and breast cancers.

Breast Density and Estradiol Are Major Determinants for Soluble TNF-TNF-R Proteins in vivo in Human Breast Tissue

High mammographic density and exposure to sex steroids are independent risk factors for breast cancer by yet unknown mechanisms. Inflammation is one hallmark of cancer and the tumor necrosis factor family of proteins (TNFSFs) and receptors (TNFRSFs) are key determinants of tissue inflammation. The relationship between TNFSFs/TNFRSFs and breast tissue density or local breast estradiol levels is unknown. We investigated whether TNFSFs and soluble TNFRSFs (sTNFRSFs) are dysregulated in vivo in human breast cancer and dense breast tissue of postmenopausal women. We explored TNFSF/TNFRSF correlations with breast density and estradiol, both locally in the breast and in abdominal subcutaneous (s.c.) fat as a measure of systemic effects. Microdialysis was used for local sampling of in vivo proteins and estradiol in a total of 73 women; 12 with breast cancer, 42 healthy postmenopausal women with different breast densities, and 19 healthy premenopausal women. Breast density was determined as lean tissue fraction (LTF) using magnetic resonance imaging. Microdialysis was also performed in estrogen receptor (ER) positive breast cancer in mice treated with the pure anti-estrogen fulvestrant and tumor tissue was subjected to immunohistochemistry. 23 members of the TNFSF/sTNFRSF families were quantified using proximity extension assay.Our data revealed upregulation of TNFSF10, 13 and 13B, TNFRSF6, 6B, 9, 11A, 11B, 13B, 14, and 19, and TNFR-1 and -2 in ER+ breast cancer in women. In dense breast tissue TNFSF10, 13, and 14, TNFRSF3, 6, 9, 10B, 13B, 14, 19, and TNFR-1 and -2 were upregulated. Certain TNFSFs/TNFRSFs were increased in premenopausal breasts relative to postmenopausal breasts. Furthermore, estradiol correlated with most of the TNFSF/sTNFRSF members, though LTF only correlated with some of the proteins. Several of these associations were breast tissue-specific, as very few correlated with estradiol in abdominal s.c. fat. Estrogen dependent regulations of TNFSF2 (TNF-α) and TNF-R2 were corroborated in ER+ breast cancer in mice. Taken together, our data indicate TNFSFs/sTNFRSFs may represent potential targetable pathways for treatment of breast cancer patients and in prevention of breast cancer development in women with dense breasts.

ROR activation by Nobiletin enhances antitumor efficacy via suppression of IκB/NF-κB signaling in triple-negative breast cancer

Triple-negative breast cancer (TNBC) is a heterogeneous disease characterized by poor response to standard therapies and therefore unfavorable clinical outcomes. Better understanding of TNBC and new therapeutic strategies are urgently needed. ROR nuclear receptors are multifunctional transcription factors with important roles in circadian pathways and other processes including immunity and tumorigenesis. Nobiletin (NOB) is a natural compound known to display anticancer effects, and our previous studies showed that NOB activates RORs to enhance circadian rhythms and promote physiological fitness in mice. Here, we identified several TNBC cell lines being sensitive to NOB, by itself or in combination. Cell and xenograft experiments showed that NOB significantly inhibited TNBC cell proliferation and motility in vitro and in vivo. ROR loss- and gain-of-function studies showed concordant effects of the NOB–ROR axis on MDA-MB-231 cell growth. Mechanistically, we found that NOB activates ROR binding to the ROR response elements (RRE) of the IκBα promoter, and NOB strongly inhibited p65 nuclear translocation. Consistent with transcriptomic analysis indicating cancer and NF-κB signaling as major pathways altered by NOB, p65-inducible expression abolished NOB effects, illustrating a requisite role of NF-κB suppression mediating the anti-TNBC effect of NOB. Finally, in vivo mouse xenograft studies showed that NOB enhanced the antitumor efficacy in mammary fat pad implanted TNBC, as a single agent or in combination with the chemotherapy agent Docetaxel. Together, our study highlights an anti-TNBC mechanism of ROR-NOB via suppression of NF-κB signaling, suggesting novel preventive and chemotherapeutic strategies against this devastating disease.

The Interplay Between Inflammation and Stromal Components in Pancreatic Cancer

Inflammation involves interactions between various immune cells, inflammatory cells, chemokines and cytokines in pancreatic cancer. Cancer cells as well as surrounding stromal and inflammatory cells establish an inflammatory tumor microenvironment (TME). Inflammation is closely associated with immunity. Meanwhile, immune cells are involved in both inflammation and immune response. Tumor-promoting inflammation and tumor-suppressive immunity are two main characteristics of the tumor microenvironment in pancreatic cancer. Yet, the mechanism of inflammation and immune response in pancreatic cancer development is still unclear due to the dual role of some cytokines and the complicated crosstalk between tumor and stromal components in TME. In this review, we outline the principal cytokines and stromal cells in the pancreatic TME that are involved in the tumor-promoting and immunosuppressive effects of inflammation, and discuss the interaction between inflammation and stromal components in pancreatic cancer progression. Moreover, the clinical approaches based on targeting TME in pancreatic cancer are also summarized. Defining the mechanisms of interplay between inflammation and stromal components will be essential for further development of anti-cancer therapies.

Chemokines in Triple-Negative Breast Cancer Heterogeneity: New Challenges for Clinical Implications

Tumor heterogeneity is a hallmark of cancer and one of the primary causes of resistance to therapies. Triple-negative breast cancer (TNBC), which accounts for 15% to 20% of all breast cancers and is the most aggressive subtype, is very diverse, connected to metastatic potential and response to therapy. It is a very diverse disease at the molecular, pathologic, and clinical levels. TNBC is substantially more likely to recur and has a worse overall survival rate following diagnosis than other breast cancer subtypes. Chemokines, low molecular weight proteins that stimulate chemotaxis, have been shown to control the cues responsible for TNBC heterogeneity. In this review, we have focused on tumor heterogeneity and the role of chemokines in modulating tumor heterogeneity, since this is the most critical issue in treating TNBC. Additionally, we examined numerous cues mediated by chemokine networks that contribute to the heterogeneity of TNBC. Recent developments in our knowledge of the chemokine networks that regulate TNBC heterogeneity may pave the door for developing difficult-to-treat TNBC treatment options.

Tumor-B-cell interactions promote isotype switching to an immunosuppressive IgG4 antibody response through upregulation of IL-10 in triple negative breast cancers

BACKGROUND

Triple negative breast cancer (TNBC) is an aggressive breast cancer for which there is currently no targeted therapy. Tumor-infiltrating B-cells (TIB) have been observed in tumor tissues of TNBC patients, but their functional role is unclear. IgG4 is one of four antibody subclasses of IgG expressed and secreted by B cells. Unlike other IgG isotypes, IgG4 has an immunosuppressive function and is induced by Th2-type cytokines. In cancers such as melanoma, IgG4 has been linked with advanced disease and poor patient survival. Therefore, we sought to determine if IgG4 + B cells are present and determine the mechanisms driving isotype switching in TNBC.

METHODS

We performed co-culture assays to examine expression of Th2 cytokines by TNBC cells with and without the presence of B cells. We also performed in vitro class switching experiments with peripheral B cells with and without co-culture with TNBC cells in the presence or absence of an IL-10 blocking antibody. We examined expression of CD20+ TIB, IgG4 and Th2 cytokines by immunohistochemistry in 152 TNBC samples. Statistical analysis was done using Log-Rank and Cox-proportional hazards tests.

RESULTS

Our findings indicate that B cells interact with TNBC to drive chronic inflammatory responses through increased expression of inflammatory cytokines including the TH2 cytokines IL-4 and IL-10. In vitro class switching studies show that interactions between TNBC cell lines and B cells drive isotype switching to the IgG4 isotype in an IL-10 dependent manner. In patient tissues, expression of IgG4 correlates with CD20 and tumor expression of IL-10. Both IgG4 and tumor IL-10 are associated to shorter recurrence free survival (RFS) and overall survival (OS) in TNBC. In a multi-variant analysis, IL-10 was associated with poor outcomes indicating that tumor IL-10 may drive immune escape.

CONCLUSIONS

These findings indicate that interactions between TIB and TNBC results in activation of chronic inflammatory signals such as IL-10 and IL-4 that drive class switching to an IgG4 + subtype which may suppress antibody driven immune responses. The presence of IgG4 + B cells may serve as a biomarker for poor prognosis.

Tumor Cell-Autonomous Pro-Metastatic Activities of PD-L1 in Human Breast Cancer Are Mediated by PD-L1-S283 and Chemokine Axes

Simple Summary

Triple-negative breast cancer (TNBC) is an aggressive disease that responds in a limited manner to immune checkpoint blockades targeting the PD-L1/PD-1 axis, suggesting that PD-L1 potentiates TNBC progression via pathways not related to immune suppression. We demonstrated that, in human breast cancer cells, PD-L1 expression increased in a cell-autonomous manner tumor cell growth, invasion and release of pro-metastatic factors; these activities were elevated by exposure to PD-1 and were markedly impaired in S283-mutated PD-L1-expressing cells. Invasion of WT-PD-L1-expressing TNBC cells depended on autocrine chemokine circuits, involving CXCR1/2, CCR2, CCR5 and their ligands. In T cell-deficient mice, WT-PD-L1 exhibited increased tumor growth and metastasis by TNBC cells, whereas S283A-PD-L1-expressing cells showed a very poor tumorigenic and metastatic profile. These findings on cell-autonomous and PD-1-induced pro-metastatic activities of PD-L1 in cancer cells suggest that treatments targeting PD-L1 could improve the efficacy of immune-targeting checkpoint inhibitors, e.g., anti-PD-1 or anti-CTLA-4 in TNBC.

Abstract

Therapies targeting the PD-L1/PD-1 axis have recently been introduced to triple-negative breast cancer (TNBC) with limited efficacy, suggesting that this axis promotes tumor progression through mechanisms other than immune suppression. Here, we over-expressed WT-PD-L1 in human TNBC cells (express endogenous PD-L1) and in luminal-A breast cancer cells (no endogenous PD-L1 expression) and demonstrated that cell-autonomous PD-L1 activities lead to increased tumor cell growth, invasion and release of pro-metastatic factors (CXCL8, sICAM-1, GM-CSF). These activities were promoted by PD-1 and were inhibited by mutating S283 in PD-L1. Invasion of WT-PD-L1-cells required signaling by chemokine receptors CXCR1/2, CCR2 and CCR5 through autocrine circuits involving CXCL8, CCL2 and CCL5. Studies with T cell-deficient mice demonstrated that cell-autonomous WT-PD-L1 activities in TNBC cells increased tumor growth and metastasis compared to knock-out (KO)-PD-L1-cells, whereas S283A-PD-L1-expressing cells had minimal ability to form tumors and did not metastasize. Overall, our findings reveal autonomous and PD-1-induced tumor-promoting activities of PD-L1 that depend on S283 and on chemokine circuits. These results suggest that TNBC patients whose tumors express PD-L1 could benefit from therapies that prevent immune suppression by targeting PD-1/CTLA-4, alongside with antibodies to PD-L1, which would allow maximal impact by mainly targeting the cancer cells.

Hormone-Related Cancer and Autoimmune Diseases: A Complex Interplay to be Discovered

Neoplasic transformation is a continuous process that occurs in the body. Even before clinical signs, the immune system is capable of recognizing these aberrant cells and reacting to suppress them. However, transformed cells acquire the ability to evade innate and adaptive immune defenses through the secretion of molecules that inhibit immune effector functions, resulting in tumor progression. Hormones have the ability to modulate the immune system and are involved in the pathogenesis of autoimmune diseases, and cancer. Hormones can control both the innate and adaptive immune systems in men and women. For example androgens reduce immunity through modulating the production of pro-inflammatory and anti-inflammatory mediators. Women are more prone than men to suffer from autoimmune diseases such as systemic lupus erythematosus, psoriasis and others. This is linked to female hormones modulating the immune system. Patients with autoimmune diseases consistently have an increased risk of cancer, either as a result of underlying immune system dysregulation or as a side effect of pharmaceutical treatments. Epidemiological data on cancer incidence emphasize the link between the immune system and cancer. We outline and illustrate the occurrence of hormone-related cancer and its relationship to the immune system or autoimmune diseases in this review. It is obvious that some observations are contentious and require explanation of molecular mechanisms and validation. As a result, future research should clarify the molecular pathways involved, including any causal relationships, in order to eventually allocate information that will aid in the treatment of hormone-sensitive cancer and autoimmune illness.

Disruption of the pentraxin 3/CD44 interaction as an efficient therapy for triple-negative breast cancers

Due to the heterogeneity and high frequency of genome mutations in cancer cells, targeting vital protumour factors found in stromal cells in the tumour microenvironment may represent an ideal strategy in cancer therapy. However, the regulation and mechanisms of potential targetable therapeutic candidates need to be investigated. An in vivo study demonstrated that loss of pentraxin 3 (PTX3) in stromal cells significantly decreased the metastasis and growth of cancer cells. Clinically, our results indicate that stromal PTX3 expression correlates with adverse prognostic features and is associated with worse survival outcomes in triple-negative breast cancer (TNBC). We also found that transforming growth factor beta 1 (TGF-β1) induces PTX3 expression by activating the transcription factor CCAAT/enhancer binding protein delta (CEBPD) in stromal fibroblasts. Following PTX3 stimulation, CD44, a PTX3 receptor, activates the downstream ERK1/2, AKT and NF-κB pathways to specifically contribute to the metastasis/invasion and stemness of TNBC MDA-MB-231 cells. Two types of PTX3 inhibitors were developed to disrupt the PTX3/CD44 interaction and they showed a significant effect on attenuating growth and restricting the metastasis/invasion of MDA-MB-231 cells, suggesting that targeting the PTX3/CD44 interaction could be a new strategy for future TNBC therapies.

C1QBP regulates apoptosis of renal cell carcinoma via modulating xanthine dehydrogenase (XDH) mediated ROS generation

Background: Complement component 1 Q subcomponent binding protein (C1QBP) plays a vital role in the progression and metabolism of cancer. Studies have shown that xanthine dehydrogenase (XDH)-derived reactive oxygen species (ROS) accelerates tumor growth, and also induces mutations or produces cytotoxic effects concurrently. However, the role of C1QBP in metabolism, oxidative stress, and apoptosis of renal cell carcinoma (RCC) cells have not yet been explored. Methods: Metabolomics assay was applied to investigate the role of C1QBP in RCC metabolism. C1QBP knockdown and overexpression cells were established via lentiviral infection and subjected to apoptosis and ROS assay in vitro. RNA stability assay was applied to characterize the mechanism of C1QBP regulating XDH transcription. In vivo, orthotopic tumor xenografts assay was performed to investigate the role of C1QBP in RCC progression. Results: Metabolomics investigation revealed that C1QBP dramatically diminished the hypoxanthine content in RCC cells. C1QBP promoted the mRNA and protein expression of hypoxanthine catabolic enzyme XDH. Meanwhile, C1QBP may affect XDH transcription by regulating the mRNA level of XDH transcriptional stimulators IL-6, TNF-α, and IFN-γ. Moreover, the expression of C1QBP and XDH was lower in RCC tumors compared with the tumor-associated normal tissues, and their down-regulation was associated with higher Fuhrman grade. C1QBP significantly increased ROS level, apoptosis, and the expression of apoptotic proteins such as cleaved caspase-3 and bax/bcl2 via regulating XDH. Conclusion: C1QBP promotes the catabolism of hypoxanthine and elevates the apoptosis of RCC cells by modulating XDH-mediated ROS generation.

Identification of Key Genes Affecting the Tumor Microenvironment and Prognosis of Triple-Negative Breast Cancer

Although the tumor microenvironment (TME) plays an important role in the development of many cancers, its roles in breast cancer, especially triple-negative breast cancer (TNBC), are not well studied. This study aimed to identify genes related to the TME and prognosis of TNBC. Firstly, we identified differentially expressed genes (DEG) in the TME of TNBC, using Expression data (ESTIMATE) datasets obtained from the Cancer Genome Atlas (TCGA) and Estimation of Stromal and Immune cells in Malignant Tumor tissues. Next, survival analysis was performed to analyze the relationship between TME and prognosis of TNBC, as well as determine DEGs. Genes showing significant differences were scored as alternative genes. A protein-protein interaction (PPI) network was constructed and functional enrichment analysis conducted using the DEG. Proteins with a degree greater than 5 and 10 in the PPI network correspond with hub genes and key genes, respectively. Finally, CCR2 and CCR5 were identified as key genes in TME and prognosis of TNBC. Finally, these results were verified using Gene Expression Omnibus (GEO) datasets and immunohistochemistry of TNBC patients. In conclusion, CCR2 and CCR5 are key genes in the TME and prognosis of TNBC with the potential of prognostic biomarkers in TNBC.

The effects of periodontitis associated microbiota on the development of oral squamous cell carcinoma

Epidemiological data have shown that periodontal bacterial infection, periodontitis, and oral squamous cell carcinoma have close relationship on the disease progress and risk. However, the specific role of periodontal microbes and their mechanism in the development of oral squamous cell carcinoma is not yet clear. In our previous work, metagenomic Illumina Mi-seq analysis was used to identify tstructure and abundance of periodontital microbiome. Accoding to the results, we used Porphyromonas.spp. and Fusobacterium.spp. as the periodontitis positive microbiota; Neisseria.spp and Corynebacterium.spp as periodontitis negative microbiota (their average relative abundance were >5%). These representative strains of the above genus were used to infect OSCC cells to explore their effect on tumor cell biology behavior, and detect the expression level of the gene in related to inflammation, migration, invasion and cell cycle. We find that periodontitis positive correlated microbiota had a promoting effect on the development of oral squamous cell carcinoma in vitro by regulating mRNA and protein expression of IL-6, IL-8, MMP-9 and Cyclin-D1. Periodontitis negative correlated microbiota had suppression effect on the development of oral squamous cell carcinoma in vitro analysis.

Key Factor Regulating Inflammatory Microenvironment, Metastasis, and Resistance in Breast Cancer: Interleukin-1 Signaling

Breast cancer is one of the top-ranked cancers for incidence and mortality worldwide. The biggest challenges in breast cancer treatment are metastasis and drug resistance, for which work on molecular evaluation, mechanism studies, and screening of therapeutic targets is ongoing. Factors that lead to inflammatory infiltration and immune system suppression in the tumor microenvironment are potential therapeutic targets. Interleukin-1 is known as a proinflammatory and immunostimulatory cytokine, which plays important roles in inflammatory diseases. Recent studies have shown that interleukin-1 cytokines drive the formation and maintenance of an inflammatory/immunosuppressive microenvironment through complex intercellular signal crosstalk and tight intracellular signal transduction, which were found to be potentially involved in the mechanism of metastasis and drug resistance of breast cancer. Some preclinical and clinical treatments or interventions to block the interleukin-1/interleukin-1 receptor system and its up- and downstream signaling cascades have also been proven effective. This study provides an overview of IL-1-mediated signal communication in breast cancer and discusses the potential of IL-1 as a therapeutic target especially for metastatic breast cancer and combination therapy and current problems, aiming at enlightening new ideas in the study of inflammatory cytokines and immune networks in the tumor microenvironment.

Chemokine signaling in cancer-stroma communications

Cancer is a multi-faceted disease in which spontaneous mutation(s) in a cell leads to the growth and development of a malignant new organ that if left undisturbed will grow in size and lead to eventual death of the organism. During this process, multiple cell types are continuously releasing signaling molecules into the microenvironment, which results in a tangled web of communication that both attracts new cell types into and reshapes the tumor microenvironment as a whole. One prominent class of molecules, chemokines, bind to specific receptors and trigger directional, chemotactic movement in the receiving cell. Chemokines and their receptors have been demonstrated to be expressed by almost all cell types in the tumor microenvironment, including epithelial, immune, mesenchymal, endothelial, and other stromal cells. This results in chemokines playing multifaceted roles in facilitating context-dependent intercellular communications. Recent research has started to shed light on these ligands and receptors in a cancer-specific context, including cell-type specificity and drug targetability. In this review, we summarize the latest research with regards to chemokines in facilitating communication between different cell types in the tumor microenvironment.

Substance P Antagonism as a Novel Therapeutic Option to Enhance Efficacy of Cisplatin in Triple Negative Breast Cancer and Protect PC12 Cells against Cisplatin-Induced Oxidative Stress and Apoptosis

Although cisplatin is very effective as a treatment strategy in triple-negative breast cancer (TNBC), it has unwarranted outcomes owing to recurrence, chemoresistance and neurotoxicity. There is critically important to find new, effective and safe therapeutics for TNBC. We determined if SP-receptor antagonism in combination with cisplatin may serve as a novel, more efficacious and safer therapeutic option than existing therapies for TNBC. We used a neuronal cell line (PC12) and two TNBC cell lines (Sum 185 and Sum 159) for these studies. We determined that the levels of cells expressing the high-affinity SP-receptor (neurokinin 1 receptor (NK1R)), as determined by flow-cytometry was significantly elevated in response to cisplatin in all three cells. We determined that treatment with aprepitant, an SP-receptor antagonist decreased cisplatin-induced, loss of viability (studied by MTT assay), production of reactive oxygen species (by DCFDA assay) and apoptosis (by flow-cytometry) in PC12 cells while it was increased in the two TNBC cells. Furthermore, we demonstrated that important genes associated with metastases, inflammation, chemoresistance and cell cycle progression are attenuated by SP-receptor antagonism in the TNBC cell line, Sum 185. These studies implicate that SP-receptor antagonism in combination with cisplatin may possibly serve as a novel, more efficacious and safer therapeutic option than existing therapies for TNBC.

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.

SHP2 inhibition enhances the anticancer effect of Osimertinib in EGFR T790M mutant lung adenocarcinoma by blocking CXCL8 loop mediated stemness

BACKGROUND

Additional epidermal growth factor receptor (EGFR) mutations confer the drug resistance to generations of EGFR targeted tyrosine kinase inhibitor (EGFR-TKI), posing a major challenge to developing effective treatment of lung adenocarcinoma (LUAD). The strategy of combining EGFR-TKI with other synergistic or sensitizing therapeutic agents are considered a promising approach in the era of precision medicine. Moreover, the role and mechanism of SHP2, which is involved in cell proliferation, cytokine production, stemness maintenance and drug resistance, has not been carefully explored in lung adenocarcinoma (LUAD).

METHODS

To evaluate the impact of SHP2 on the efficacy of EGFR T790M mutant LUAD cells to Osimertinib, SHP2 inhibition was tested in Osimertinib treated LUAD cells. Cell proliferation and stemness were tested in SHP2 modified LUAD cells. RNA sequencing was performed to explore the mechanism of SHP2 promoted stemness.

RESULTS

This study demonstrated that high SHP2 expression level correlates with poor outcome of LUAD patients, and SHP2 expression is enriched in Osimertinib resistant LUAD cells. SHP2 inhibition suppressed the cell proliferation and damaged the stemness of EGFR T790M mutant LUAD. SHP2 facilitates the secretion of CXCL8 cytokine from the EGFR T790M mutant LUAD cells, through a CXCL8-CXCR1/2 positive feedback loop that promotes stemness and tumorigenesis. Our results further show that SHP2 mediates CXCL8-CXCR1/2 feedback loop through ERK-AKT-NFκB and GSK3β-β-Catenin signaling in EGFR T790M mutant LUAD cells.

CONCLUSIONS

Our data revealed that SHP2 inhibition enhances the anti-cancer effect of Osimertinib in EGFR T790M mutant LUAD by blocking CXCL8-CXCR1/2 loop mediated stemness, which may help provide an alternative therapeutic option to enhance the clinical efficacy of osimertinib in EGFR T790M mutant LUAD patients.

Autophagy inhibition in breast cancer cells induces ROS-mediated MIF expression and M1 macrophage polarization

Autophagy can function as a survival mechanism for cancer cells and therefore, its inhibition is currently being explored as a therapy for different cancer types. For breast cancer, triple negative breast cancer (TNBC) is the subtype most sensitive to the inhibition of autophagy; but its inhibition has also been shown to promote ROS-dependent secretion of macrophage migration inhibitory factor (MIF), a pro-tumorigenic cytokine. In this work, we explore the role of MIF in breast cancer, the mechanism by which autophagy inhibition promotes MIF secretion and its effects on neighboring cancer cell signaling and macrophage polarization. We analyzed MIF mRNA expression levels in tumors from breast cancer patients from different subtypes and found that Luminal B, HER2 and Basal subtypes, which are associated to high proliferation, displayed high MIF levels. However, MIF expression had no prognostic relevance in any breast cancer subtype. In addition, we found that autophagy inhibition in 66cl4 TNBC cells increased intracellular Reactive Oxygen Species (ROS) levels, which increased MIF expression and secretion. MIF secreted from 66cl4 TNBC cells induced the activation of MIF-regulated pathways in syngeneic cell lines, increasing Akt phosphorylation in 4T1 cells and ERK phosphorylation in 67NR cells. Regarding MIF/ chemokine receptors, higher levels of CD74 and CXCR2 were found in TNBC tumor cell lines when compared to non-tumorigenic cells and CXCR7 was elevated in the highly metastatic 4T1 cell line. Finally, secreted MIF from autophagy deficient 66cl4 cells induced macrophage polarization towards the M1 subtype. Together, our results indicate an important role for the inhibition of autophagy in the regulation of ROS-mediated MIF gene expression and secretion, with paracrine effects on cancer cell signaling and pro-inflammatory repercussions in macrophage M1 polarization. This data should be considered when considering the inhibition of autophagy as a therapy for different types of cancer.

Cancer-Associated Fibroblasts in Breast Cancer Treatment Response and Metastasis

Breast cancer (BrCa) is the leading cause of death among women worldwide, with about one million new cases diagnosed each year. In spite of the improvements in diagnosis, early detection and treatment, there is still a high incidence of mortality and failure to respond to current therapies. With the use of several well-established biomarkers, such as hormone receptors and human epidermal growth factor receptor-2 (HER2), as well as genetic analysis, BrCa patients can be categorized into multiple subgroups: Luminal A, Luminal B, HER2-enriched, and Basal-like, with specific treatment strategies. Although chemotherapy and targeted therapies have greatly improved the survival of patients with BrCa, there is still a large number of patients who relapse or who fail to respond. The role of the tumor microenvironment in BrCa progression is becoming increasingly understood. Cancer-associated fibroblasts (CAFs) are the principal population of stromal cells in breast tumors. In this review, we discuss the current understanding of CAFs' role in altering the tumor response to therapeutic agents as well as in fostering metastasis in BrCa. In addition, we also review the available CAFs-directed molecular therapies and their potential implications for BrCa management.

Overexpression of GLUT3 promotes metastasis of triple-negative breast cancer by modulating the inflammatory tumor microenvironment

Triple-negative breast cancer (TNBC) exhibits a higher level of glycolytic capacity and are commonly associated with an inflammatory microenvironment, but the regulatory mechanism and metabolic crosstalk between the tumor and tumor microenvironment (TME) are largely unresolved. Here, we show that glucose transporter 3 (GLUT3) is particularly elevated in TNBC and associated with metastatic progression and poor prognosis in breast cancer patients. Expression of GLUT3 is crucial for promoting the epithelial-to-mesenchymal transition and enhancing invasiveness and distant metastasis of TNBC cells. Notably, GLUT3 is correlated with inflammatory gene expressions and is associated with M1 tumor-associated macrophages (TAMs), at least in part by C-X-C Motif Chemokine Ligand 8 (CXCL8). We found that expression of GLUT3 regulates CXCL8 production in TNBC cells. Secretion of CXCL8 participates in GLUT3-overexpressing TNBC cells-elicited activation of inflammatory TAMs, which further enhances GLUT3 expression and mobility of TNBC cells. Our findings demonstrate that aerobic glycolysis in TNBC not only promotes aggressiveness of tumor cells but also initiates a positive regulatory loop for enhancing tumor progression by modulating the inflammatory TME.

Continuous Inflammatory Stimulation Leads via Metabolic Plasticity to a Prometastatic Phenotype in Triple-Negative Breast Cancer Cells

Chronic inflammation promotes cancer progression by affecting the tumor cells and their microenvironment. Here, we demonstrate that a continuous stimulation (~6 weeks) of triple-negative breast tumor cells (TNBC) by the proinflammatory cytokines tumor necrosis factor α (TNFα) + interleukin 1β (IL-1β) changed the expression of hundreds of genes, skewing the cells towards a proinflammatory phenotype. While not affecting stemness, the continuous TNFα + IL-1β stimulation has increased tumor cell dispersion and has induced a hybrid metabolic phenotype in TNBC cells; this phenotype was indicated by a transcription-independent elevation in glycolytic activity and by increased mitochondrial respiratory potential (OXPHOS) of TNBC cells, accompanied by elevated transcription of mitochondria-encoded OXPHOS genes and of active mitochondria area. The continuous TNFα + IL-1β stimulation has promoted in a glycolysis-dependent manner the activation of p65 (NF-κB), and the transcription and protein expression of the prometastatic and proinflammatory mediators sICAM-1, CCL2, CXCL8 and CXCL1. Moreover, when TNBC cells were stimulated continuously by TNFα + IL-1β in the presence of a glycolysis inhibitor, their conditioned media had reduced ability to recruit monocytes and neutrophils in vivo. Such inflammation-induced metabolic plasticity, which promotes prometastatic cascades in TNBC, may have important clinical implications in treatment of TNBC patients.

Inflammation-Induced Tumorigenesis and Metastasis

Inflammation, especially chronic inflammation, plays a pivotal role in tumorigenesis and metastasis through various mechanisms and is now recognized as a hallmark of cancer and an attractive therapeutic target in cancer. In this review, we discuss recent advances in molecular mechanisms of how inflammation promotes tumorigenesis and metastasis and suppresses anti-tumor immunity in various types of solid tumors, including esophageal, gastric, colorectal, liver, and pancreatic cancer as well as hematopoietic malignancies.

Claudin-Low Breast Cancer Inflammatory Signatures Support Polarization of M1-Like Macrophages with Protumoral Activity

We previously reported that triple-negative breast cancer (BRCA) cells overexpress the cytokines GM-CSF, G-CSF, MCP-1, and RANTES, and when monocytes were 3-D co-cultured with them, M1-like macrophages were generated with the ability to induce aggressive features in luminal BRCA cell lines. These include upregulation of mesenchymal and stemness markers and invasion. In this study, we stimulated peripheral blood monocytes with the four cytokines and confirmed their capacity to generate protumoral M1-like macrophages. Using the METABRIC BRCA database, we observed that GM-CSF, MCP-1, and RANTES are associated with triple-negative BRCA and reduced overall survival, particularly in patients under 55 years of age. We propose an extended M1-like macrophage proinflammatory signature connected with these three cytokines. We found that the extended M1-like macrophage signature coexists with monocyte/macrophage, Th1 immune response, and immunosuppressive signatures, and all are enriched in claudin-low BRCA samples, and correlate with reduced patient overall survival. Furthermore, we observed that all these signatures are also present in mesenchymal carcinomas of the colon (COAD) and bladder (BLCA). The claudin-low tumor subtype has an adverse clinical outcome and remains poorly understood. This study places M1 macrophages as potential protumoral drivers in already established cancers, and as potential contributors to claudin-low aggressiveness and poor prognosis.

Cytokine Production by Tumor Bioptate at Different Pathological Prognostic Stages in Breast Cancer

Differences in the production of cytokines by tumor biopsy specimens were revealed depending on the pathological prognostic stages of The American Joint Committee on Cancer (AJCC) of invasive nonspecific breast carcinoma (INBC). The patients with a predominant absence of metastases in combination with a triple negative molecular subtype differ from the patients with other pathological prognostic stages in the cytokine-producing tumor resource of IL-18, IL-1β, IL-1Ra, TNF-α, GM-CSF, and MCP-1.

Mesenchymal stem/stromal cell-based therapy: mechanism, systemic safety and biodistribution for precision clinical applications

Mesenchymal stem/stromal cells (MSCs) are a promising resource for cell-based therapy because of their high immunomodulation ability, tropism towards inflamed and injured tissues, and their easy access and isolation. Currently, there are more than 1200 registered MSC clinical trials globally. However, a lack of standardized methods to characterize cell safety, efficacy, and biodistribution dramatically hinders the progress of MSC utility in clinical practice. In this review, we summarize the current state of MSC-based cell therapy, focusing on the systemic safety and biodistribution of MSCs. MSC-associated risks of tumor initiation and promotion and the underlying mechanisms of these risks are discussed. In addition, MSC biodistribution methodology and the pharmacokinetics and pharmacodynamics of cell therapies are addressed. Better understanding of the systemic safety and biodistribution of MSCs will facilitate future clinical applications of precision medicine using stem cells.

Understanding the function of the tumor microenvironment, and compounds from marine organisms for breast cancer therapy

The pathology and physiology of breast cancer (BC), including metastasis, and drug resistance, is driven by multiple signaling pathways in the tumor microenvironment (TME), which hamper antitumor immunity. Recently, long non-coding RNAs have been reported to mediate pathophysiological develop-ments such as metastasis as well as immune suppression within the TME. Given the complex biology of BC, novel personalized therapeutic strategies that address its diverse pathophysiologies are needed to improve clinical outcomes. In this review, we describe the advances in the biology of breast neoplasia, including cellular and molecular biology, heterogeneity, and TME. We review the role of novel molecules such as long non-coding RNAs in the pathophysiology of BC. Finally, we provide an up-to-date overview of anticancer compounds extracted from marine microorganisms, crustaceans, and fishes and their synergistic effects in combination with other anticancer drugs. Marine compounds are a new discipline of research in BC and offer a wide range of anti-cancer effects that could be harnessed to target the various pathways involved in BC development, thus assisting current therapeutic regimens.

Persistent Inflammatory Stimulation Drives the Conversion of MSCs to Inflammatory CAFs That Promote Pro-Metastatic Characteristics in Breast Cancer Cells

The pro-inflammatory cytokines tumor necrosis factor α (TNFα) and interleukin 1β (IL-1β) are expressed simultaneously and have tumor-promoting roles in breast cancer. In parallel, mesenchymal stem cells (MSCs) undergo conversion at the tumor site to cancer-associated fibroblasts (CAFs), which are generally connected to enhanced tumor progression. Here, we determined the impact of consistent inflammatory stimulation on stromal cell plasticity. MSCs that were persistently stimulated by TNFα + IL-1β (generally 14-18 days) gained a CAF-like morphology, accompanied by prominent changes in gene expression, including in stroma/fibroblast-related genes. These CAF-like cells expressed elevated levels of vimentin and fibroblast activation protein (FAP) and demonstrated significantly increased abilities to contract collagen gels. Moreover, they gained the phenotype of inflammatory CAFs, as indicated by the reduced expression of α smooth muscle actin (αSMA), increased proliferation, and elevated expression of inflammatory genes and proteins, primarily inflammatory chemokines. These inflammatory CAFs released factors that enhanced tumor cell dispersion, scattering, and migration; the inflammatory CAF-derived factors elevated cancer cell migration by stimulating the chemokine receptors CCR2, CCR5, and CXCR1/2 and Ras-activating receptors, expressed by the cancer cells. Together, these novel findings demonstrate that chronic inflammation can induce MSC-to-CAF conversion, leading to the generation of tumor-promoting inflammatory CAFs.

Inflammation-Driven Breast Tumor Cell Plasticity: Stemness/EMT, Therapy Resistance and Dormancy

Cellular heterogeneity poses an immense therapeutic challenge in cancer due to a constant change in tumor cell characteristics, endowing cancer cells with the ability to dynamically shift between states. Intra-tumor heterogeneity is largely driven by cancer cell plasticity, demonstrated by the ability of malignant cells to acquire stemness and epithelial-to-mesenchymal transition (EMT) properties, to develop therapy resistance and to escape dormancy. These different aspects of cancer cell remodeling are driven by intrinsic as well as by extrinsic signals, the latter being dominated by factors of the tumor microenvironment. As part of the tumor milieu, chronic inflammation is generally regarded as a most influential player that supports tumor development and progression. In this review article, we put together recent findings on the roles of inflammatory elements in driving forward key processes of tumor cell plasticity. Using breast cancer as a representative research system, we demonstrate the critical roles played by inflammation-associated myeloid cells (mainly macrophages), pro-inflammatory cytokines [such as tumor necrosis factor α (TNFα) and interleukin 6 (IL-6)] and inflammatory chemokines [primarily CXCL8 (interleukin 8, IL-8) and CXCL1 (GROα)] in promoting tumor cell remodeling. These inflammatory components form a common thread that is involved in regulation of the three plasticity levels: stemness/EMT, therapy resistance, and dormancy. In view of the fact that inflammatory elements are a common denominator shared by different aspects of tumor cell plasticity, it is possible that their targeting may have a critical clinical benefit for cancer patients.

Tumor-stroma biomechanical crosstalk: a perspective on the role of caveolin-1 in tumor progression

Tumor stiffening is a hallmark of malignancy that actively drives tumor progression and aggressiveness. Recent research has shed light onto several molecular underpinnings of this biomechanical process, which has a reciprocal crosstalk between tumor cells, stromal fibroblasts, and extracellular matrix remodeling at its core. This dynamic communication shapes the tumor microenvironment; significantly determines disease features including therapeutic resistance, relapse, or metastasis; and potentially holds the key for novel antitumor strategies. Caveolae and their components emerge as integrators of different aspects of cell function, mechanotransduction, and ECM-cell interaction. Here, we review our current knowledge on the several pivotal roles of the essential caveolar component caveolin-1 in this multidirectional biomechanical crosstalk and highlight standing questions in the field.

Possible Beneficial Effects of N-Acetylcysteine for Treatment of Triple-Negative Breast Cancer

N-acetylcysteine (NAC) is a widely used antioxidant with therapeutic potential. However, the cancer-promoting effect of NAC observed in some preclinical studies has raised concerns regarding its clinical use. Reactive oxygen species (ROS) can mediate signaling that results in both cancer-promoting and cancer-suppressing effects. The beneficial effect of NAC may depend on whether the type of cancer relies on ROS signaling for its survival and metastasis. Triple-negative breast cancer (TNBC) has aggressive phenotypes and is currently treated with standard chemotherapy as the main systemic treatment option. Particularly, basal-like TNBC cells characterized by inactivated BRCA1 and mutated TP53 produce high ROS levels and rely on ROS signaling for their survival and malignant progression. In addition, the high ROS levels in TNBC cells can mediate the interplay between cancer cells and the tissue microenvironment (TME) to trigger the recruitment and conversion of stromal cells and induce hypoxic responses, thus leading to the creation of cancer-supportive TMEs and increased cancer aggressiveness. However, NAC treatment effectively reduces the ROS production and ROS-mediated signaling that contribute to cell survival, metastasis, and drug resistance in TNBC cells. Therefore, the inclusion of NAC in standard chemotherapy could probably provide additional benefits for TNBC patients.

Key genes in youth colorectal cancer based on data mining and verification by reverse transcription-quantitative PCR

In recent years, among all patients with colorectal cancer, the proportion of young patients has been gradually increasing. However, the molecular mechanisms involved in colorectal cancer in the young are largely unknown. In the present study the Gene Expression Omnibus (GEO) and The Cancer Genome Atlas datasets were integrated to elucidate the key gene biomarkers in these patients. The GSE41657 and GSE41258 datasets were downloaded from the GEO database. By screening for differentially expressed genes, Gene Ontology analysis, Kyoto Encyclopedia of Genes and Genomes pathway analysis, protein-protein interaction analysis, hub gene screening and survival analysis, two key genes, CXCL8 and VEGFA, which were enriched in cancer pathways, were obtained. Reverse transcription-quantitative (RT-q)PCR was performed to verify the outcome obtained by bioinformatics analysis. In conclusion, the present study identified two key genes using bioinformatics analysis and RT-qPCR validation. These results indicated that the candidate genes may be involved in the progression of colorectal cancer in young people, and these two genes may act as ideal prognostic indicators or therapeutic targets for colorectal cancer in the youth.

[Influence of the HLDF differentiation factor on the production of cytokines by bio-tissues of breast tissue in its non-malignant diseases and in invasive carcinoma of a non-specific type]

We studied the effect of the HLDF differentiation factor on production of cytokines by biopsy samples of nonmalignant breast diseases (ND) and invasive breast carcinoma of no special type (IBC-NST), in the absence and presence of lymphogenic metastasis: IBC-NST patients werw subdivided into groups on the prognostic protocol of the 8th edition of the AJCC committee. Group IA consisted of patients with T1-T2 tumor sizes, and predominantly with positive expression of estrogen and progesterone receptors (ER+/PR+/HER2-); it also included one patient with the HER2+ (ER-/PR-/HER2+) molecular subtype. The IB group was mainly composed of patients with T2 tumor size, with the presence of lymphogenic metastasis (in 8 out of 10) patients and with positive expression of estrogen and progesterone receptors (ER+/PR+/HER2-) and it also included three patients with the HER2+ (ER-/PR-/HER2+) molecular subtype. Group IIA consisted of patients with T1-T2 tumor sizes, mainly with no metastases in the lymph nodes (in 11 out of 12 patients) and with a triple negative molecular subtype. Group IIB included patients with T2 tumor size, the presence of nodal metastasis and the expression of markers of ER-/PR-/HER2 - and ER-/PR-/HER2+. Group IIIA consisted of patients with tumor size T1-T3, with the presence of nodal metastasis and the expression of markers of ER-/PR+/HER2+ and ER-/PR-/HER2+. Group IIIC consisted of patients with T3 tumor size, lymphogenic metastasis, and expression of ER-/PR-/HER2-markers (triple negative molecular subtype). Due to a limited number of patients in the groups IIB, IIIA and IIIC, as well as due to more severe clinical and pathological stages, according to the prognostic Protocol of the 8th edition of the AJCC Committee, they were pooled into group III. Concentrations of IL-2, IL-4, IL-6, IL-8, IL-10, IL-17, IL-18, IL-1β, IL-1Ra, TNF-α, IFN-γ, G-CSF, GM-CSF, VEGF and MCP-1 were assayed in supernatants of biopsy specimens of breast tissue. Results have shown that with IBC-NST, a statistically significantly higher level of spontaneous production (SP) by biopsy specimens of IL-17, IL-18, IFN-γ and VEGF, and a lower level of SP IL-6 as compared with ND. Patients of all clinical and pathological groups showed a high VEGF spontaneous production as compared with ND, while statistically significant differences from patients with ND were not found in IL-17 spontaneous production in group IB patients, and IL-18 spontaneous production were absent in group IA. Only in patients with IA and IB, the IL-6 spontaneous production was lower as compared to ND, and the IL-8 spontaneous production was lower in the IA group. IFN-γ spontaneous production was higher in patients with IBC-NST group IIA as compared with ND. Under the influence of the HLDF differentiation factor, it was found that the parameters of IBC-NST patients were statistically significantly higher in the production of IL-1Ra, IL-17, IL-18 and VEGF, and statistically significantly lower in the production of IL-6 as compared to ND. HLDF had a higher impact on the content of IL-18 in IBC-NST patients than in ND. After HDLF sublimation IL-6 values were lower in patients of groups IA and IB, and HLDF-induced IL-17 production was higher only in patients of group IA. Statistically significant differences in the index of influence of HLDF (IVHLDF), representing ratio of the cytokine concentration in the supernatants of a biopsy specimen stimulated by HLDF to spontaneous cytokine production, were found between ND and IBC-NST in the case of on IFN-γ production, and also in the case of IL-4 production (between patients in the absence and presence of lymphogenic metastasis). IVHLDF for production of IL-6, IL-8 and TNF-α was lower in group IIA patients compared to group IA, and IVHLDF for production of GM-CSF and MCP-1 was lower in group IIA as compared to group III, in addition IVHLDF for MCP-1 products was lower in group IIA as compared to ND. The HLDF effect on the cytokine production by the tumor and its microenvironment was different in ND patients and IBC-NST patients. HDLF suppressed IFN-γ production in the pooled group of IBC-NST patients; HLDF mainly had a suppressive effect on the production of IL-6, IL-8, TNF-α, GM-CSF and MCP-1 in IBC-NST patients of group IIA.

The Roles of Stroma-Derived Chemokine in Different Stages of Cancer Metastases

The intricate interplay between malignant cells and host cellular and non-cellular components play crucial role in different stages of tumor development, progression, and metastases. Tumor and stromal cells communicate to each other through receptors such as integrins and secretion of signaling molecules like growth factors, cytokines, chemokines and inflammatory mediators. Chemokines mediated signaling pathways have emerged as major mechanisms underlying multifaceted roles played by host cells during tumor progression. In response to tumor stimuli, host cells-derived chemokines further activates signaling cascades that support the ability of tumor cells to invade surrounding basement membrane and extra-cellular matrix. The host-derived chemokines act on endothelial cells to increase their permeability and facilitate tumor cells intravasation and extravasation. The tumor cells-host neutrophils interaction within the vasculature initiates chemokines driven recruitment of inflammatory cells that protects circulatory tumor cells from immune attack. Chemokines secreted by tumor cells and stromal immune and non-immune cells within the tumor microenvironment enter the circulation and are responsible for formation of a "pre-metastatic niche" like a "soil" in distant organs whereby circulating tumor cells "seed' and colonize, leading to formation of metastatic foci. Given the importance of host derived chemokines in cancer progression and metastases several drugs like Mogamulizumab, Plerixafor, Repertaxin among others are part of ongoing clinical trial which target chemokines and their receptors against cancer pathogenesis. In this review, we focus on recent advances in understanding the complexity of chemokines network in tumor microenvironment, with an emphasis on chemokines secreted from host cells. We especially summarize the role of host-derived chemokines in different stages of metastases, including invasion, dissemination, migration into the vasculature, and seeding into the pre-metastatic niche. We finally provide a brief description of prospective drugs that target chemokines in different clinical trials against cancer.

Prospects for NK Cell Therapy of Sarcoma

Simple Summary

Sarcomas are a group of aggressive tumors originating from mesenchymal tissues. Patients with advanced disease have poor prognosis due to the ineffectiveness of current treatment protocols. A subset of lymphocytes called natural killer (NK) cells is capable of effective surveillance and clearance of sarcomas, constituting a promising tool for immunotherapeutic treatment. However, sarcomas can cause impairment in NK cell function, associated with enhanced tumor growth and dissemination. In this review, we discuss the molecular mechanisms of sarcoma-mediated suppression of NK cells and their implications for the design of novel NK cell-based immunotherapies against sarcoma.

Abstract

Natural killer (NK) cells are innate lymphoid cells with potent antitumor activity. One of the most NK cell cytotoxicity-sensitive tumor types is sarcoma, an aggressive mesenchyme-derived neoplasm. While a combination of radical surgery and radio- and chemotherapy can successfully control local disease, patients with advanced sarcomas remain refractory to current treatment regimens, calling for novel therapeutic strategies. There is accumulating evidence for NK cell-mediated immunosurveillance of sarcoma cells during all stages of the disease, highlighting the potential of using NK cells as a therapeutic tool. However, sarcomas display multiple immunoevasion mechanisms that can suppress NK cell function leading to an uncontrolled tumor outgrowth. Here, we review the current evidence for NK cells’ role in immune surveillance of sarcoma during disease initiation, promotion, progression, and metastasis, as well as the molecular mechanisms behind sarcoma-mediated NK cell suppression. Further, we apply this basic understanding of NK–sarcoma crosstalk in order to identify and summarize the most promising candidates for NK cell-based sarcoma immunotherapy.

Inflammation Is Associated with Worse Outcome in the Whole Cohort but with Better Outcome in Triple-Negative Subtype of Breast Cancer Patients

Inflammation has been linked with cancer, but whether it is part of the problem or part of the solution remains to be a matter of debate in breast cancer. Our group and others have demonstrated that inflammation aggravates cancer progression; however, some claim that inflammation may support immune cell infiltration and suppress cancer. We defined the gene set variation analysis of the Molecular Signatures Database Hallmark inflammatory response gene set as the inflammatory pathway score and analyzed 3632 tumors in total from 4 breast cancer cohorts (METABRIC, TCGA, GSE25066, and GSE21094). In the whole breast cancer cohort, high-score tumors were associated with aggressive clinical characteristics, such as worse disease specific survival, higher Nottingham histological grade, and younger age. Inflammatory score was significantly higher in triple-negative (TNBC) as well as basal and normal subtypes compared with the other subtypes, which suggest that the detrimental effect of high level of inflammation may be because it includes a more aggressive subtype. On the contrary, high score within TNBC was significantly associated with better survival. TNBC with high score enriched not only IFN-α, IFN-γ response, IL-2/STAT5 signaling, Allograft rejection, Complement, p53 pathway, Reactive Oxygen, and Apoptosis but also TNF-α signaling, IL6-JAK-STAT signaling, TGF-β signaling, Coagulation, Angiogenesis, EMT, KRAS signaling, and PI3K-AKT-MTOR signaling gene sets. High score was associated with mainly favorable anticancerous immune cell infiltration as well as Leukocyte fraction, TIL regional fraction, Lymphocyte infiltration, IFN-γ response, TGF-β response, and cytolytic activity scores. Although the inflammatory pathway score was not associated with neoadjuvant treatment response, it associated with expressions of immune checkpoint molecules. In conclusion, inflammation was associated with worse outcome in the whole breast cancer cohort, but with better outcome in TNBC, which was associated with favorable anticancerous immune response and immune cell infiltrations.

Mitochondrial DNA Affects the Expression of Nuclear Genes Involved in Immune and Stress Responses in a Breast Cancer Model

Tumor cells without mitochondrial (mt) DNA (ρ0 cells) are auxotrophic for uridine, and their growth is supported by pyruvate. While ATP synthesis in ρ0 cells relies on glycolysis, they fail to form tumors unless they acquire mitochondria from stromal cells. Mitochondrial acquisition restores respiration that is essential for de novo pyrimidine biosynthesis and for mitochondrial ATP production. The physiological processes that underpin intercellular mitochondrial transfer to tumor cells lacking mtDNA and the metabolic remodeling and restored tumorigenic properties of cells that acquire mitochondria are not well understood. Here, we investigated the changes in mitochondrial and nuclear gene expression that accompany mtDNA deletion and acquisition in metastatic murine 4T1 breast cancer cells. Loss of mitochondrial gene expression in 4T1ρ0 cells was restored in cells recovered from subcutaneous tumors that grew from 4T1ρ0 cells following acquisition of mtDNA from host cells. In contrast, the expression of most nuclear genes that encode respiratory complex subunits and mitochondrial ribosomal subunits was not greatly affected by loss of mtDNA, indicating ineffective mitochondria-to-nucleus communication systems for these nuclear genes. Further, analysis of nuclear genes whose expression was compromised in 4T1ρ0 cells showed that immune- and stress-related genes were the most highly differentially expressed, representing over 70% of those with greater than 16-fold higher expression in 4T1 compared with 4T1ρ0 cells. The monocyte recruiting chemokine, Ccl2, and Psmb8, a subunit of the immunoproteasome that generates MHCI-binding peptides, were the most highly differentially expressed. Early monocyte/macrophage recruitment into the tumor mass was compromised in 4T1ρ0 cells but recovered before mtDNA could be detected. Taken together, our results show that mitochondrial acquisition by tumor cells without mtDNA results in bioenergetic remodeling and re-expression of genes involved in immune function and stress adaptation.

Cytoplasmic CCR7 (CCR7c) immunoexpression is associated with local tumor recurrence in triple-negative breast cancer

BACKGROUND

Triple-negative breast cancer (TNBC) is a subtype of cancer, which tests negative for estrogen receptors, progesterone receptors, and lacks overexpression of the human epidermal growth factor 2 (C-erbB2, HER2/neu) gene. The expression of chemokines and their receptors, including CCR7, has been described in several types of cancer, contributing to tumor progression.

AIM OF THE STUDY

This study investigated the association between the membrane and cytoplasmic CCR7 expression and the prognosis of TNBC.

MATERIALS AND METHODS

Surgical paraffin histopathology blocks and clinico-pathological data were assessed from 133 patients. Samples were analyzed by immunohistochemistry and immunofluorescence using the Tissue Microarray technique for scoring the intensity of CCR7 expression.

RESULTS

TNBC patients in which the CCR7 labeling was predominantly in the cytoplasm of tumor cells presented increased local tumor recurrence (P = 0.033). Conversely, there was no statistical difference in five-year overall survival between the patients with low (77%) versus high (80%) cytoplasmic CCR7 expression (P = 0.7104). Additionally, the risk of death between these groups was 1.19 (95% CI = 0.48-2.91).

CONCLUSION

The cytoplasmic CCR7 expression associates with an increased incidence of tumor relapse in TNBC, not affecting patients survival. Consequently, the cell compartment in which the CCR7 localizes could serve as a prognostic marker in this cancer subtype.

6-Methoxymellein Isolated from Carrot (Daucus carota L.) Targets Breast Cancer Stem Cells by Regulating NF-κB Signaling

The presence of breast cancer stem cells (BCSCs) induces the aggressive progression and recurrence of breast cancer. These cells are drug resistant, have the capacity to self-renew and differentiate and are involved in recurrence and metastasis, suggesting that targeting BCSCs may improve treatment efficacy. In this report, methanol extracts of carrot root were purified by means of silica gel, Sephadex LH-20, and preparative high-performance liquid chromatography to isolate a compound targeting mammosphere formation. We isolated the compound 6-methoxymellein, which inhibits the proliferation and migration of breast cancer cells, reduces mammosphere growth, decreases the proportion of CD44⁺/CD24⁻ cells in breast cancer cells and decreases the expression of stemness-associated proteins c-Myc, Sox-2 and Oct4. 6-Methoxymellein reduces the nuclear localization of nuclear factor-κB (NF-κB) subunit p65 and p50. Subsequently, 6-methoxymellein decreases the mRNA transcription and secretion of IL-6 and IL-8. Our data suggest that 6-methoxymellein may be an anticancer agent that inhibits BCSCs via NF-κB/IL-6 and IL-8 regulation.

The IL1β-IL1R signaling is involved in the stimulatory effects triggered by hypoxia in breast cancer cells and cancer-associated fibroblasts (CAFs)

Background

Hypoxia plays a relevant role in tumor-related inflammation toward the metastatic spread and cancer aggressiveness. The pro-inflammatory cytokine interleukin-1β (IL-β) and its cognate receptor IL1R1 contribute to the initiation and progression of breast cancer determining pro-tumorigenic inflammatory responses. The transcriptional target of the hypoxia inducible factor-1α (HIF-1α) namely the G protein estrogen receptor (GPER) mediates a feedforward loop coupling IL-1β induction by breast cancer-associated fibroblasts (CAFs) to IL1R1 expression by breast cancer cells toward the regulation of target genes and relevant biological responses.

Methods

In order to ascertain the correlation of IL-β with HIF-1α and further hypoxia-related genes in triple-negative breast cancer (TNBC) patients, a bioinformatics analysis was performed using the information provided by The Invasive Breast Cancer Cohort of The Cancer Genome Atlas (TCGA) project and Molecular Taxonomy of Breast Cancer International Consortium (METABRIC) datasets. Gene expression correlation, statistical analysis and gene set enrichment analysis (GSEA) were carried out with R studio packages. Pathway enrichment analysis was evaluated with Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway. TNBC cells and primary CAFs were used as model system. The molecular mechanisms implicated in the regulation of IL-1β by hypoxia toward a metastatic gene expression profile and invasive properties were assessed performing gene and protein expression studies, PCR arrays, gene silencing and immunofluorescence analysis, co-immunoprecipitation and ChiP assays, ELISA, cell spreading, invasion and spheroid formation.

Results

We first determined that IL-1β expression correlates with the levels of HIF-1α as well as with a hypoxia-related gene signature in TNBC patients. Next, we demonstrated that hypoxia triggers a functional liaison among HIF-1α, GPER and the IL-1β/IL1R1 signaling toward a metastatic gene signature and a feed-forward loop of IL-1β that leads to proliferative and invasive responses in TNBC cells. Furthermore, we found that the IL-1β released in the conditioned medium of TNBC cells exposed to hypoxic conditions promotes an invasive phenotype of CAFs.

Conclusions

Our data shed new light on the role of hypoxia in the activation of the IL-1β/IL1R1 signaling, which in turn triggers aggressive features in both TNBC cells and CAFs. Hence, our findings provide novel evidence regarding the mechanisms through which the hypoxic tumor microenvironment may contribute to breast cancer progression and suggest further targets useful in more comprehensive therapeutic strategies.