SSTP1, a Host Defense Peptide, Exploits the Immunomodulatory IL6 Pathway to Induce Apoptosis in Cancer Cells

Abstract Background: The anticancer activities of host defense peptides (HDPs) are mainly attributed to their cell penetrating activity. Accordingly, several approaches based on machine learning, calculating the membrane pore formation ability, have been proposed for the anti-cancer peptide identification. Since the membranolytic activity can lead to nonspecific effects, like hemolysis, the therapeutic application of such molecules is limited. In this context, we considered the immunomodulatory activity of HDPs, which is regulated by specific membrane targets and immunomodulatory pathways in immune cells. As many immunomodulators are aberrantly expressed in cancer cells, the possibility of the activation of an immunomodulatory pathway was investigated for a novel anticancer HDP, SSTP1.Methods: The fourteen mature peptides identified by shotgun cloning from the frog-skin secretions were screened for cytotoxicity in oral cancer cells. The mechanism of action of the selected peptide, SSTP1 was investigated in comparison to its inactive mutant, SSTP2. An RNA-Seq coupled with pathway enrichment analysis was performed to identify the upstream signaling leading to the mitochondrial pathway of apoptosis. Since the activation of the IL6/IL6R pathway was suggested, we performed in silico docking studies to find the binding of SSTP1 to the IL6/IL6Rα/gp130 complex. The dynamic simulation predicted the conformational changes in the active site residues. The confocal co-localization studies, pull-down assay, FRET analysis, western blot and reporter assays were performed to elucidate the role of the IL6/IL6R pathway in SSTP1-induced apoptosis. Specific small molecule inhibitors and neutralizing antibodies were used to ascertain the role of the IL6/IL6Rα/gp130 complex in the activation of JNK/AP1 pathway-dependent cell death.Results: SSTP1, a novel temporin, modulates the IL6 pathway and induces apoptosis when it binds to IL6Rα on the active IL6/IL6Rα/gp130 complex, rearranging the active site residues. In contrast to the IL6 blockers inhibiting JAK/STAT activity, SSTP1 shifts the proliferative IL6/JAK/STAT signaling to the apoptotic IL6/JNK/AP1 pathway. In IL6Rα-overexpressing cancer cells, apoptosis is preferred over the membranolytic activity, upon SSTP1 treatment.Conclusions: Here, we provide the evidence of an HDP-induced signaling through immunomodulators, leading to apoptosis in cancer cells. Our study also implies the importance of identifying the targets of HDPs for their clinical application

Download Full-text

Hippo/YAP Signaling Choreographs The Tumor Immune Microenvironment to Promote Triple Negative Breast Cancer Progression Via TAZ/IL-34 Axis

10.21203/rs.3.rs-524972/v1 ◽

2021 ◽

Author(s):

Zheng Wang ◽

Fan Wang ◽

Xin-Yuan Ding ◽

Tian-En Li ◽

Hao-Yu Wang ◽

...

Keyword(s):

Breast Cancer ◽

Cancer Cells ◽

Cancer Progression ◽

Triple Negative Breast Cancer ◽

Immune Cells ◽

Triple Negative ◽

Transforming Growth Factor ◽

Immune Cell ◽

Hippo Pathway ◽

Immune Microenvironment

Abstract Background: Growing evidence suggests that the bidirectional interactions between cancer cells and their surrounding environment namely the tumor microenvironment (TME), contributes to cancer progression, metastasis, and resistance to treatment. Intense investigation of Hippo pathway, which controls multiple central cellular function to tumorigenesis, was focused on cancer cells. However, the role of Hippo pathway in modulating tumor–stromal interactions in triple negative breast cancer remains largely unknow. This study therefore focused on revealing effects of Hippo-YAP/TAZ signaling to immune microenvironment.Methods: The correlation between Hippo/YAP signaling and the abundance of immune cells were estimated by Immune Cell Abundance Identifier. Clinical TNBC samples from 120 patients were analyzed to assess the correlation between TAZ expression and disease prognosis as well as tumor-infiltrating immune cells. Inflammatory immune profiles, bioinformatics analysis and chromatin immunoprecipitation were performed to identify the expression of immune-related genes that were regulated by TAZ. An in vitro co-culture system was applied to investigate the crosstalk between TNBC cells and tumor-associated macrophages (TAMs) modulated by the TAZ/interleukin 34 (IL-34) axis. In vivo tumor growth and metastasis models were used to evaluate the pro-tumor functions of TAZ, IL-34, and TAMs as well as the antitumor efficacy of anti-PD-L1 and IL-34/colony-stimulating factor 1 receptor (CSF-1R) blockade.Results: In TNBC patients, high activity of Hippo pathway was correlated with decreased number of T cells, upregulated TAM infiltration, and poor prognosis. TAZ could directly regulate IL-34 and PD-L1 expression and promote IL-34 secretion in TNBC cells, leading to increased TAM infiltration and distant metastasis. TAM-derived transforming growth factor beta 1 (TGF-β1) could also induce TAZ expression in TNBC cells, thus forming a positive feedback loop between TNBC cells and TAMs. Furthermore, targeting the TAZ/IL-34 axis through its CSF-1R inhibitor could dramatically decrease TAM infiltration and significantly improve anti-PD-L1 efficacy in inhibiting metastasis in TNBC.Conclusions: Activity of Hippo pathway was associated with worse disease outcomes in TNBC and could increase TAM infiltration through the TAZ/IL-34 axis, leading to an immunosuppressive microenvironment and impairing the treatment efficacy of anti-PD-L1. Thus, the TAZ/IL-34 axis can serve as a novel target for TNBC patients.

Download Full-text

The role of the organic anion transporting polypeptide OATP4A1 in immunactivation in colorectal cancer and inflammatory colon disease.

Journal of Clinical Oncology ◽

10.1200/jco.2014.32.3_suppl.481 ◽

2014 ◽

Vol 32 (3_suppl) ◽

pp. 481-481

Author(s):

Christoph Alexander Ausch ◽

Simone Zotter ◽

Maidah Scheikh ◽

Heike Bauer ◽

Marina Mollik ◽

...

Keyword(s):

Colorectal Cancer ◽

Cancer Cells ◽

Cancer Progression ◽

Immune Cells ◽

Immune Cell ◽

Organic Anion ◽

Staining Intensity ◽

Image Analysis System ◽

Cellular Markers

481 Background: OATP-transporter proteins, such as OATP4A1, present influence cancer progression by providing compounds (hormones, prostaglandins, cyclic nucleotides, second messenger proteins, drugs) which either inhibit or stimulate tumor cells growth. Therefore, OATP expression in cancer cells and in the stroma, i.e., the microenvironment surrounding the epithelial cells can become a critical parameter. Methods: OATP4A1 was investigated in paraffin-embedded specimens from 148 patients with colorectal cancer and 20 with diverticulitis by immunohistochemistry (IHC) on an automatic quantitative microscopic image analysis system (TissuesFaxs). With the Histoquest program, the immunoreactive score (IRS), was calculated from the degree of the staining intensity and the number of OATP4A1-positive cells. To identify OATP4A1+-cells, double-immunofluorescence staining (IF) was done with antibodies against appropriate cellular markers. Results: OATP4A1 was located in the membrane and cytosol of colon cancer cells and immune cells, while membranous OATP4A1staining was seen in normal mucosa. OATP4A1 levels were higher in cancer cells in patients without tumor recurrence for up to 5 years (NR) than in patients with an early relapse (R) having IRS of 4391±231 and 3026±373 (Mean±SEM), respectively. Highest OATP4A1 levels were observed in immune cells in the tumors of Rs (IRS, 5712 ±254, while in NRs they were lower (IRS: 3549±358; p=0.05). In both groups, OATP4A1 levels in stroma cells were low (288±54 vs. 611±82). OATP4A1 expressing immune cell subtypes in cancer and diverticulitis sections were identified as CD45+ leukocytes, CD3+ T- and CD20+ B-cells, CD68+ macrophages, CD34+precursor cells. OATP4A1 was not detectable in Conclusions: High levels of OATP4A1 in immune cells in malignant and non-malignant colon disease suggest a role of the transporter in the activation of the immune system in malignant and non-malignant colon disease. Whether OATP4A1 might be a therapeutical target has to be established.

Download Full-text

Platelets, immune cells and the coagulation cascade; friend or foe of the circulating tumour cell?

Molecular Cancer ◽

10.1186/s12943-021-01347-1 ◽

2021 ◽

Vol 20 (1) ◽

Author(s):

Mark P. Ward ◽

Laura E. Kane ◽

Lucy A. Norris ◽

Bashir M. Mohamed ◽

Tanya Kelly ◽

...

Keyword(s):

Cancer Cells ◽

Immune Cells ◽

Immune Cell ◽

Circulatory System ◽

Morphological Characteristics ◽

Metastatic Potential ◽

Coagulation Cascade ◽

Molecular Profile ◽

Great Promise ◽

Liquid Biopsies

AbstractCancer cells that transit from primary tumours into the circulatory system are known as circulating tumour cells (CTCs). These cancer cells have unique phenotypic and genotypic characteristics which allow them to survive within the circulation, subsequently extravasate and metastasise. CTCs have emerged as a useful diagnostic tool using “liquid biopsies” to report on the metastatic potential of cancers. However, CTCs by their nature interact with components of the blood circulatory system on a constant basis, influencing both their physical and morphological characteristics as well as metastatic capabilities. These properties and the associated molecular profile may provide critical diagnostic and prognostic capabilities in the clinic. Platelets interact with CTCs within minutes of their dissemination and are crucial in the formation of the initial metastatic niche. Platelets and coagulation proteins also alter the fate of a CTC by influencing EMT, promoting pro-survival signalling and aiding in evading immune cell destruction. CTCs have the capacity to directly hijack immune cells and utilise them to aid in CTC metastatic seeding processes. The disruption of CTC clusters may also offer a strategy for the treatment of advance staged cancers. Therapeutic disruption of these heterotypical interactions as well as direct CTC targeting hold great promise, especially with the advent of new immunotherapies and personalised medicines. Understanding the molecular role that platelets, immune cells and the coagulation cascade play in CTC biology will allow us to identify and characterise the most clinically relevant CTCs from patients. This will subsequently advance the clinical utility of CTCs in cancer diagnosis/prognosis.

Download Full-text

When Cells Suffocate: Autophagy in Cancer and Immune Cells under Low Oxygen

International Journal of Cell Biology ◽

10.1155/2011/470597 ◽

2011 ◽

Vol 2011 ◽

pp. 1-13 ◽

Cited By ~ 16

Author(s):

Katrin Schlie ◽

Jaeline E. Spowart ◽

Luke R. K. Hughson ◽

Katelin N. Townsend ◽

Julian J. Lum

Keyword(s):

Tumor Microenvironment ◽

Cancer Cells ◽

Immune Cells ◽

Immune Cell ◽

Treatment Strategies ◽

Patient Treatment ◽

Low Oxygen ◽

Tumor Environment ◽

And Function ◽

The Impact

Hypoxia is a signature feature of growing tumors. This cellular state creates an inhospitable condition that impedes the growth and function of all cells within the immediate and surrounding tumor microenvironment. To adapt to hypoxia, cells activate autophagy and undergo a metabolic shift increasing the cellular dependency on anaerobic metabolism. Autophagy upregulation in cancer cells liberates nutrients, decreases the buildup of reactive oxygen species, and aids in the clearance of misfolded proteins. Together, these features impart a survival advantage for cancer cells in the tumor microenvironment. This observation has led to intense research efforts focused on developing autophagy-modulating drugs for cancer patient treatment. However, other cells that infiltrate the tumor environment such as immune cells also encounter hypoxia likely resulting in hypoxia-induced autophagy. In light of the fact that autophagy is crucial for immune cell proliferation as well as their effector functions such as antigen presentation and T cell-mediated killing of tumor cells, anticancer treatment strategies based on autophagy modulation will need to consider the impact of autophagy on the immune system.

Download Full-text

Search for receptors in immune cells that bind cancer cell antigens and their activation in silent cases

10.7287/peerj.preprints.27670 ◽

2019 ◽

Author(s):

Wenfa Ng

Keyword(s):

Immune System ◽

Amino Acid ◽

Cancer Cells ◽

Cell Lines ◽

Cancer Cell ◽

Immune Cells ◽

Immune Cell ◽

Checkpoint Inhibitors ◽

Host Cells ◽

Immune Receptor

The immune checkpoint plays an important role in keeping immune cells in check for protecting tissues and organs from attack by the body’s own immune system. Similar concepts also apply in how cancer cells managed to fool immune cells through the surface display of particular antigens that mimic those exhibited by normal body cells. Specifically, cancer cells display antigens that bind to receptors on immune cells that subsequently prevent an attack on the cancer cells. Such binding between cancer antigens and immune cell receptors can be prevented through the use of checkpoint inhibitors antibodies specific for particular receptors on immune cells; thereby, unleashing immune cells to mount an immune response against cancer cells. While demonstrating good remissions in many patients where tumours shrunk substantially after administration of checkpoint inhibitors, cases exist where an overactivated immune system cause harm to organs and tissues culminating in multiple organ failure. Analysis of such toxicity effects of checkpoint inhibitors revealed that generic nature of targeted immune receptor plays a pivotal role in determining extent of side effects. Specifically, if the target immune receptor participates in checkpoints that prevent immune cells from attacking host cells, unleashing such receptors in cancer therapy may have untoward effects on patient’s health. Hence, the goal should be the selection of immune cell receptor specific to cancer cell antigens and which does not bind antigens or ligands displayed by the body’s cells. Such receptors would provide ideal targets for the development of checkpoint inhibitor antibodies for unleashing immune cells against cancer cells. To search for non-generic receptors that bind cancer cell antigens only, a combined computational and experimental approach could be used where ensemble of surface antigens on cancer cells and available receptors on immune cells could be profiled by biochemical assays. Downstream purification of ligands and receptors would provide for both structural elucidation and amino acid sequencing useful for bioinformatic search of homologous sequences. Knowledge of the antigens’ and receptors’ structures and amino acid sequence would subsequently serve as inputs to computational algorithms that models molecular docking events between receptor and antigen. This paves the way for heterologous expression of putative ligand and receptor in cell lines cultured in co-culture format for assessing binding between ligand and receptor, and more importantly, its physiological effects. Ability of immune receptor to bind to ligands on normal cells could also be assessed. Similar co-culture studies could be conducted with cancer cells and different immune cell types to check for reproducibility of observed effect in cell lines. Finally, antibodies could be raised for candidate receptors whose inhibition would not result in systemic attack of immune cells on host cells.

Download Full-text

Human β-Defensin 3 Inhibits Cell Wall Biosynthesis in Staphylococci

Infection and Immunity ◽

10.1128/iai.00688-09 ◽

2010 ◽

Vol 78 (6) ◽

pp. 2793-2800 ◽

Cited By ~ 164

Author(s):

Vera Sass ◽

Tanja Schneider ◽

Miriam Wilmes ◽

Christian Körner ◽

Alessandro Tossi ◽

...

Keyword(s):

Electron Microscopy ◽

Cell Wall ◽

Host Defense ◽

Transcriptional Response ◽

Cell Wall Biosynthesis ◽

Host Defense Peptides ◽

Lipid Ii ◽

Transmission Electron ◽

Host Defense Peptide

ABSTRACT Human β-defensin 3 (hBD3) is a highly charged (+11) cationic host defense peptide, produced by epithelial cells and neutrophils. hBD3 retains antimicrobial activity against a broad range of pathogens, including multiresistant Staphylococcus aureus, even under high-salt conditions. Whereas antimicrobial host defense peptides are assumed to act by permeabilizing cell membranes, the transcriptional response pattern of hBD3-treated staphylococcal cells resembled that of vancomycin-treated cells (V. Sass, U. Pag, A. Tossi, G. Bierbaum, and H. G. Sahl, Int. J. Med. Microbiol. 298:619-633, 2008) and suggested that inhibition of cell wall biosynthesis is a major component of the killing process. hBD3-treated cells, inspected by transmission electron microscopy, showed localized protrusions of cytoplasmic contents, and analysis of the intracellular pool of nucleotide-activated cell wall precursors demonstrated accumulation of the final soluble precursor, UDP-MurNAc-pentapeptide. Accumulation is typically induced by antibiotics that inhibit membrane-bound steps of cell wall biosynthesis and also demonstrates that hBD3 does not impair the biosynthetic capacity of cells and does not cause gross leakage of small cytoplasmic compounds. In in vitro assays of individual membrane-associated cell wall biosynthesis reactions (MraY, MurG, FemX, and penicillin-binding protein 2 [PBP2]), hBD3 inhibited those enzymes which use the bactoprenol-bound cell wall building block lipid II as a substrate; quantitative analysis suggested that hBD3 may stoichiometrically bind to lipid II. We report that binding of hBD3 to defined, lipid II-rich sites of cell wall biosynthesis may lead to perturbation of the biosynthesis machinery, resulting in localized lesions in the cell wall as demonstrated by electron microscopy. The lesions may then allow for osmotic rupture of cells when defensins are tested under low-salt conditions.

Download Full-text

Toll-Like Receptor 2 at the Crossroad between Cancer Cells, the Immune System, and the Microbiota

International Journal of Molecular Sciences ◽

10.3390/ijms21249418 ◽

2020 ◽

Vol 21 (24) ◽

pp. 9418

Author(s):

Antonino Di Lorenzo ◽

Elisabetta Bolli ◽

Lidia Tarone ◽

Federica Cavallo ◽

Laura Conti

Keyword(s):

Cancer Cells ◽

Cancer Progression ◽

Immune Cell ◽

Primary Response ◽

Toll Like Receptor ◽

Scientific Debate ◽

Anti Cancer ◽

Double Edge Sword ◽

Toll Like Receptor 2 ◽

Immunosuppressive Microenvironment

Toll-like receptor 2 (TLR2) expressed on myeloid cells mediates the recognition of harmful molecules belonging to invading pathogens or host damaged tissues, leading to inflammation. For this ability to activate immune responses, TLR2 has been considered a player in anti-cancer immunity. Therefore, TLR2 agonists have been used as adjuvants for anti-cancer immunotherapies. However, TLR2 is also expressed on neoplastic cells from different malignancies and promotes their proliferation through activation of the myeloid differentiation primary response protein 88 (MyD88)/nuclear factor kappa-light-chain-enhancer of activated B cell (NF-κB) pathway. Furthermore, its activation on regulatory immune cells may contribute to the generation of an immunosuppressive microenvironment and of the pre-metastatic niche, promoting cancer progression. Thus, TLR2 represents a double-edge sword, whose role in cancer needs to be carefully understood for the setup of effective therapies. In this review, we discuss the divergent effects induced by TLR2 activation in different immune cell populations, cancer cells, and cancer stem cells. Moreover, we analyze the stimuli that lead to its activation in the tumor microenvironment, addressing the role of danger, pathogen, and microbiota-associated molecular patterns and their modulation during cancer treatments. This information will contribute to the scientific debate on the use of TLR2 agonists or antagonists in cancer treatment and pave the way for new therapeutic avenues.

Download Full-text

Metabolic Reprogramming Induces Immune Cell Dysfunction in the Tumor Microenvironment of Multiple Myeloma

Frontiers in Oncology ◽

10.3389/fonc.2020.591342 ◽

2021 ◽

Vol 10 ◽

Author(s):

Shaojie Wu ◽

Huixian Kuang ◽

Jin Ke ◽

Manfei Pi ◽

Dong-Hua Yang

Keyword(s):

Multiple Myeloma ◽

Tumor Microenvironment ◽

Cancer Progression ◽

Immune Cells ◽

Immune Cell ◽

Metabolic Reprogramming ◽

Metabolic Phenotype ◽

Cell Dysfunction ◽

Promising Therapeutic Approach ◽

Tumor Survival

Tumor cells rewire metabolism to meet their increased nutritional demands, allowing the maintenance of tumor survival, proliferation, and expansion. Enhancement of glycolysis and glutaminolysis is identified in most, if not all cancers, including multiple myeloma (MM), which interacts with a hypoxic, acidic, and nutritionally deficient tumor microenvironment (TME). In this review, we discuss the metabolic changes including generation, depletion or accumulation of metabolites and signaling pathways, as well as their relationship with the TME in MM cells. Moreover, we describe the crosstalk among metabolism, TME, and changing function of immune cells during cancer progression. The overlapping metabolic phenotype between MM and immune cells is discussed. In this sense, targeting metabolism of MM cells is a promising therapeutic approach. We propose that it is important to define the metabolic signatures that may regulate the function of immune cells in TME in order to improve the response to immunotherapy.

Download Full-text

Search for receptors in immune cells that bind cancer cell antigens and their activation in silent cases

10.7287/peerj.preprints.27670v1 ◽

2019 ◽

Author(s):

Wenfa Ng

Keyword(s):

Immune System ◽

Amino Acid ◽

Cancer Cells ◽

Cell Lines ◽

Cancer Cell ◽

Immune Cells ◽

Immune Cell ◽

Checkpoint Inhibitors ◽

Host Cells ◽

Immune Receptor

The immune checkpoint plays an important role in keeping immune cells in check for protecting tissues and organs from attack by the body’s own immune system. Similar concepts also apply in how cancer cells managed to fool immune cells through the surface display of particular antigens that mimic those exhibited by normal body cells. Specifically, cancer cells display antigens that bind to receptors on immune cells that subsequently prevent an attack on the cancer cells. Such binding between cancer antigens and immune cell receptors can be prevented through the use of checkpoint inhibitors antibodies specific for particular receptors on immune cells; thereby, unleashing immune cells to mount an immune response against cancer cells. While demonstrating good remissions in many patients where tumours shrunk substantially after administration of checkpoint inhibitors, cases exist where an overactivated immune system cause harm to organs and tissues culminating in multiple organ failure. Analysis of such toxicity effects of checkpoint inhibitors revealed that generic nature of targeted immune receptor plays a pivotal role in determining extent of side effects. Specifically, if the target immune receptor participates in checkpoints that prevent immune cells from attacking host cells, unleashing such receptors in cancer therapy may have untoward effects on patient’s health. Hence, the goal should be the selection of immune cell receptor specific to cancer cell antigens and which does not bind antigens or ligands displayed by the body’s cells. Such receptors would provide ideal targets for the development of checkpoint inhibitor antibodies for unleashing immune cells against cancer cells. To search for non-generic receptors that bind cancer cell antigens only, a combined computational and experimental approach could be used where ensemble of surface antigens on cancer cells and available receptors on immune cells could be profiled by biochemical assays. Downstream purification of ligands and receptors would provide for both structural elucidation and amino acid sequencing useful for bioinformatic search of homologous sequences. Knowledge of the antigens’ and receptors’ structures and amino acid sequence would subsequently serve as inputs to computational algorithms that models molecular docking events between receptor and antigen. This paves the way for heterologous expression of putative ligand and receptor in cell lines cultured in co-culture format for assessing binding between ligand and receptor, and more importantly, its physiological effects. Ability of immune receptor to bind to ligands on normal cells could also be assessed. Similar co-culture studies could be conducted with cancer cells and different immune cell types to check for reproducibility of observed effect in cell lines. Finally, antibodies could be raised for candidate receptors whose inhibition would not result in systemic attack of immune cells on host cells.

Download Full-text