Background: Dissociating glucocorticoid receptor (GR) ligands hold great promise for treating inflammatory disorders since it is assumed that they exert beneficial activities mediated by transrepression but avoid adverse effects of GR action requiring transactivation. Here we challenged this paradigm by investigating 2-(4-acetoxyphenyl)-2-chloro-N-methyl-ethylammonium chloride (CpdA), a dissociating non-steroidal GR ligand, in the context of experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis (MS). Methodology/Principal Findings: CpdA inhibited pro-inflammatory mediators in myelin-specific T cells and fibroblasts in a GR-dependent manner while gene activation was abolished. However, it also induced massive apoptosis in various cell types even in the absence of the GR by engaging a Bcl-2- and caspase-dependent pathway. H-1 NMR spectroscopy corroborated these findings by revealing that CpdA dissolved in buffered solutions rapidly decomposes into aziridine intermediates known to act as alkylating pro-apoptotic agents. Importantly, the dichotomy of CpdA action also became evident in vivo. Administration of high-dose CpdA to mice was lethal while treatment of EAE with low to intermediate amounts of CpdA dissolved in water significantly ameliorated the disease. The beneficial effect of CpdA required expression of the GR in T cells and was achieved by down regulating LFA-1 and CD44 on peripheral Th cells and by repressing IL-17 production. Conclusions/Significance: CpdA has significant therapeutic potential although adverse effects severely compromise its application in vivo. Hence, non-steroidal GR ligands require careful analysis prior to their translation into new therapeutic concepts.
BACKGROUND: Cancer-associated fibroblasts (CAFs) support tumour progression and invasion, and they secrete abundant extracellular matrix (ECM) that may shield tumour cells from immune checkpoint or kinase inhibitors. Targeting CAFs using drugs that revert their differentiation, or inhibit their tumour-supportive functions, has been considered as an anti-cancer strategy. METHODS: We have used human and murine cell culture models, atomic force microscopy (AFM), microarray analyses, CAF/tumour cell spheroid co-cultures and transgenic fibroblast reporter mice to study how targeting HDACs using small molecule inhibitors or siRNAs re-directs CAF differentiation and function in vitro and in vivo. RESULTS: From a small molecule screen, we identified Scriptaid, a selective inhibitor of HDACs 1/3/8, as a repressor of TGF beta-mediated CAF differentiation. Scriptaid inhibits ECM secretion, reduces cellular contraction and stiffness, and impairs collective cell invasion in CAF/tumour cell spheroid co-cultures. Scriptaid also reduces CAF abundance and delays tumour growth in vivo. CONCLUSIONS: Scriptaid is a well-tolerated and effective HDACi that reverses many of the functional and phenotypic properties of CAFs. Impeding or reversing CAF activation/function by altering the cellular epigenetic regulatory machinery could control tumour growth and invasion, and be beneficial in combination with additional therapies that target cancer cells or immune cells directly.
Mitochondria are dynamic organelles, the morphology of which results from an equilibrium between two opposing processes, fusion and fission. Mitochondrial fusion relies on dynamin‐related GTPases, the mitofusins (MFN1 and 2) in the outer mitochondrial membrane and OPA1 (optic atrophy 1) in the inner mitochondrial membrane. Apart from a role in the maintenance of mitochondrial DNA, little is known about the physiological role of mitochondrial fusion. Here we report that mitochondria hyperfuse and form a highly interconnected network in cells exposed to selective stresses. This process precedes mitochondrial fission when it is triggered by apoptotic stimuli such as UV irradiation or actinomycin D. Stress‐induced mitochondrial hyperfusion (SIMH) is independent of MFN2, BAX/BAK, and prohibitins, but requires L‐OPA1, MFN1, and the mitochondrial inner membrane protein SLP‐2. In the absence of SLP‐2, L‐OPA1 is lost and SIMH is prevented. SIMH is accompanied by increased mitochondrial ATP production and represents a novel adaptive pro‐survival response against stress.
Tumor microenvironment consists of the extracellular matrix (ECM), stromal cells, such as fibroblasts (FBs) and cancer associated fibroblasts (CAFs), and a myriad of soluble factors. In many tumor types, including pancreatic tumors, the interplay between stromal cells and the other tumor microenvironment components leads to desmoplasia, a cancer-specific type of fibrosis that hinders treatment. Transforming growth factor beta (TGF-β) and CAFs are thought to play a crucial role in this tumor desmoplastic reaction, although the involved mechanisms are unknown. Optical/fluorescence microscopy, atomic force microscopy, image processing techniques, invasion assay in 3D collagen I gels and real-time PCR were employed to investigate the effect of TGF-β on normal pancreatic FBs and CAFs with regard to crucial cellular morphodynamic characteristics and relevant gene expression involved in tumor progression and metastasis. CAFs present specific myofibroblast-like characteristics, such as α-smooth muscle actin expression and cell elongation, they also form more lamellipodia and are softer than FBs. TGF-β treatment increases cell stiffness (Young's modulus) of both FBs and CAFs and increases CAF's (but not FB's) elongation, cell spreading, lamellipodia formation and spheroid invasion. Gene expression analysis shows that these morphodynamic characteristics are mediated by Rac, RhoA and ROCK expression in CAFs treated with TGF-β. TGF-β modulates CAFs', but not FBs', cell shape, stiffness and invasion. Our findings elucidate on the effects of TGF-β on CAFs' behavior and stiffness providing new insights into the mechanisms involved. [Display omitted] •CAFs are more elongated and express higher levels of α-SMA than FBs.•CAFs have oriented stress fibers and are softer than FBs with more lamellipodia.•TGF-β promotes cell spreading in CAFs through Rac.•TGF-β makes CAFs more elongated with more lamellipodia and promotes their invasion.•RhoA and ROCK expression is altered in CAFs treated with TGF-β.
Stroma cells, together with extracellular matrix components, provide the microenvironment that is pivotal for cancer cell growth, invasion and metastatic progression. Characteristic stroma alterations accompany or even precede the malignant conversion of epithelial cells. Crucial in this process are fibroblasts, also termed myofibroblasts or cancer-associated fibroblasts (CAFs) that are located in the vicinity of the neoplastic epithelial cells. They are able to modify the phenotype of the epithelial cells by direct cell-to-cell contacts, through soluble factors or by modification of extracellular matrix components. Seminal functional studies in various cancer types, including breast, colon, prostate and lung cancer, have confirmed the concept that fibroblasts can determine the fate of the epithelial cell, since they are able to promote malignant conversion as well as to revert tumour cells to a normal phenotype. This review focuses on characteristic changes of fibroblasts in cancer and provides the experimental background elucidating functional properties of CAFs in the carcinogenic process. A possible implication in lung carcinogenesis is emphasised. Finally, a laser-capture- and microarray-based approach is presented, which comprehensively characterises carcinoma-associated fibroblasts in their in vivo environment for the identification of potential targets for anti-cancer therapy.
Background: Cortidis rhizoma (Huanglian) and its major therapeutic component, berberine, have drawn extensive attention in recent years for their anti-cancer properties. Growth inhibitory effects of berberine on multiple types of human cancer cells have been reported. Berberine inhibits invasion, induces cell cycle arrest and apoptosis in human cancer cells. The anti-inflammatory property of berberine, involving inhibition of Signal Transducer and Activator of Transcription 3 (STAT3) activation, has also been documented. Methods: In this study, we have examined the effects of berberine on tumorigenicity and growth of nasopharyngeal carcinoma (NPC) cells and their relationship to STAT3 signaling using both in vivo and in vitro models. Results: Berberine effectively inhibited the tumorigenicity and growth of an EBV-positive NPC cell line (C666-1) in athymic nude mice. Inhibition of tumorigenic growth of NPC cells in vivo was correlated with effective inhibition of STAT3 activation in NPC cells inside the tumor xenografts grown in nude mice. In vitro, berberine inhibited both constitutive and IL-6-induced STAT3 activation in NPC cells. Inhibition of STAT3 activation by berberine induced growth inhibition and apoptotic response in NPC cells. Tumor-associated fibroblasts were found to secret IL-6 and the conditioned medium harvested from the fibroblasts also induced STAT3 activation in NPC cells. Furthermore, STAT3 activation by conditioned medium of tumor-associated fibroblasts could be blocked by berberine or antibodies against IL-6 and IL-6R. Conclusions: Our observation that berberine effectively inhibited activation of STAT3 induced by tumor-associated fibroblasts suggests a role of berberine in modulating the effects of tumor stroma on the growth of NPC cells. The effective inhibition of STAT3 activation in NPC cells by berberine supports its potential use in the treatment of NPC.
Introduction: T helper (Th)-17 cells are increased in systemic sclerosis (SSc). We therefore assessed whether Th17 cells could modulate the inflammatory and fibrotic responses in dermal fibroblasts from healthy donors (HD) and SSc individuals. Methods: Fibroblasts were obtained from 14 SSc and 8 HD skin biopsies. Th17 clones were generated from healthy peripheral blood upon enrichment of CC chemokine receptor (CCR) 4/CCR6/CD161 expressing cells. Their cytokine production was assessed by flow cytometry and multiplex beads immunoassay. Fibroblast production of monocyte chemoattractant protein (MCP)-1, interleukin (IL)-8, matrix metalloproteinase (MMP)-1, tissue inhibitor of metalloproteinase (TIMP)-1, MMP-2 and type-I collagen was quantified by enzyme-linked immunosorbent assay (ELISA) and radioimmunoassay (RIA), and changes in their transcription levels assessed by real-time PCR. Intracellular signals were dissected by western blot and the use of pharmacological inhibitors. IL-17A, tumor necrosis factor (TNF) and interferon-gamma (IFN-gamma) blocking reagents were used to assess the specificity of the observed effects. Results: IL-17A increased MCP-1, IL-8 and MMP-1 production in a dose-dependent manner while having no effect on type I collagen in HD and SSc fibroblasts both at protein and mRNA levels. Nuclear factor-kappa B (NF-kappa B) and p38 were preferentially involved in the induction of MCP-1 and IL-8, while MMP-1 was most dependent on c-Jun N-terminal kinase (JNK). Supernatants of activated Th17 clones largely enhanced MCP-1, IL-8 and MMP-1 while strongly inhibiting collagen production. Of note, the production of MCP-1 and IL-8 was higher, while collagen inhibition was lower in SSc compared to HD fibroblasts. The Th17 clone supernatant effects were mostly dependent on additive/synergistic activities between IL-17A, TNF and in part IFN-gamma. Importantly, the inhibition of type I collagen production induced by the Th17 clone supernatants was completely abrogated by blockade of IL-17A, TNF and IFN-gamma mostly in SSc fibroblasts, revealing an intrinsic resistance to inhibitory signals in SSc. Conclusions: Our findings demonstrate that in vitro Th17 cells elicit pro-inflammatory responses while restraining collagen production. Thus, the increased Th17 cell number observed in SSc may impact on the inflammatory component of the disease simultaneously potentially providing a protective role against fibrosis.
Background: Idiopathic pulmonary fibrosis (IPF) is a progressive lung disease with poor prognosis. The kinase inhibitor nintedanib specific for vascular endothelial growth factor receptor (VEGFR), platelet-derived growth factor receptor (PDGFR) and fibroblast growth factor receptor (FGFR) significantly reduced the rate of decline of forced vital capacity versus placebo. Aim: To determine the in vitro effect of nintedanib on primary human lung fibroblasts. Methods: Fibroblasts were isolated from lungs of IPF patients and from non-fibrotic controls. We assessed the effect of VEGF, PDGF-BB and basic FGF (bFGF) +/- nintedanib on: (i) expression/activation of VEGFR, PDGFR, and FGFR, (ii) cell proliferation, secretion of (iii) matrix metalloproteinases (MMP), (iv) tissue inhibitor of metalloproteinase (TIMP), and (v) collagen. Results: IPF fibroblasts expressed higher levels of PDGFR and FGFR than controls. PDGF-BB, bFGF, and VEGF caused a pro-proliferative effect which was prevented by nintedanib. Nintedanib enhanced the expression of pro-MMP-2, and inhibited the expression of TIMP-2. Transforming growth factor-beta-induced secretion of collagens was inhibited by nintedanib. Conclusion: Our data demonstrate a significant anti-fibrotic effect of nintedanib in IPF fibroblasts. This effect consists of the drug's anti-proliferative capacity, and on its effect on the extracellular matrix, the degradation of which seems to be enhanced.
Although accumulating evidence suggests that the crosstalk between malignant cells and cancer-associated fibroblasts (CAFs) actively contributes to tumour growth and metastatic dissemination, therapeutic strategies targeting tumour stroma are still not common in the clinical practice. Metal-based nanomaterials have been shown to exert excellent cytotoxic and anti-cancerous activities, however, their effects on the reactive stroma have never been investigated in details. Thus, using feasible in vitro and in vivo systems to model tumour microenvironment, we tested whether the presence of gold, silver or gold-core silver-shell nanoparticles exerts anti-tumour and metastasis suppressing activities by influencing the tumour-supporting activity of stromal fibroblasts. We found that the presence of gold-core silver-shell hybrid nanomaterials in the tumour microenvironment attenuated the tumour cell-promoting behaviour of CAFs, and this phenomenon led to a prominent attenuation of metastatic dissemination in vivo as well. Mechanistically, transcriptome analysis on tumour-promoting CAFs revealed that silver-based nanomaterials trigger expressional changes in genes related to cancer invasion and tumour metastasis. Here we report that metal nanoparticles can influence the cancer-promoting activity of tumour stroma by affecting the gene expressional and secretory profiles of stromal fibroblasts and thereby altering their intrinsic crosstalk with malignant cells. This potential of metal nanomaterials should be exploited in multimodal treatment approaches and translated into improved therapeutic outcomes.