Tranilast inhibits cell proliferation and migration and promotes apoptosis in murine breast cancer

Strategy of targeting the tumor microenvironment via inhibition of fibroblast/fibrosis remodeling new era to cancer chemo-immunotherapy resistance

The use of repurposing drugs that may have neoplastic and anticancer effects increases the efficiency and decrease resistance to chemotherapy drugs through a biochemical and mechanical transduction mechanisms through modulation of fibroblast/fibrosis remodeling in tumor microenvironment (TME). Interestingly, fibroblast/fibrosis remodeling plays a vital role in mediating cancer metastasis and drug resistance after immune chemotherapy. The most essential hypothesis for induction of chemo-immunotherapy resistance is via activation of fibroblast/fibrosis remodeling and preventing the infiltration of T cells after is mainly due to the interference between cytoskeleton, mechanical, biochemical, metabolic, vascular, and remodeling signaling pathways in TME. The structural components of the tumor that can be targeted in the fibroblast/fibrosis remodeling include the depletion of the TME components, targeting the cancer-associated fibroblasts and tumor associated macrophages, alleviating the mechanical stress within the ECM, and normalizing the blood vessels. It has also been found that during immune-chemotherapy, TME injury and fibroblast/fibrosis remodeling causes the up-regulation of inhibitory signals and down-regulation of activated signals, which results in immune escape or chemo-resistance of the tumor. In this regard, repurposing or neo-adjuvant drugs with various transduction signaling mechanisms, including anti-fibrotic effects, are used to target the TME and fibroblast/fibrosis signaling pathway such as angiotensin 2, transforming growth factor-beta, physical barriers of the TME, cytokines and metabolic factors which finally led to the reverse of the chemo-resistance. Consistent to many repurposing drugs such as pirfenidone, metformin, losartan, tranilast, dexamethasone and pentoxifylline are used to decrease immune-suppression by abrogation of TME inhibitory signal that stimulates the immune system and increases efficiency and reduces resistance to chemotherapy drugs. To overcome immunosuppression based on fibroblast/fibrosis remodeling, in this review, we focus on inhibitory signal transduction, which is the physical barrier, alleviates mechanical stress and prevents mechano-metabolic activation.

The Role of the Aryl Hydrocarbon Receptor (AhR) and Its Ligands in Breast Cancer

Breast cancer is a complex disease which is defined by numerous cellular and molecular markers that can be used to develop more targeted and successful therapies. The aryl hydrocarbon receptor (AhR) is overexpressed in many breast tumor sub-types, including estrogen receptor -positive (ER+) tumors; however, the prognostic value of the AhR for breast cancer patient survival is not consistent between studies. Moreover, the functional role of the AhR in various breast cancer cell lines is also variable and exhibits both tumor promoter- and tumor suppressor- like activity and the AhR is expressed in both ER-positive and ER-negative cells/tumors. There is strong evidence demonstrating inhibitory AhR-Rα crosstalk where various AhR ligands induce ER degradation. It has also been reported that different structural classes of AhR ligands, including halogenated aromatics, polynuclear aromatics, synthetic drugs and other pharmaceuticals, health promoting phytochemical-derived natural products and endogenous AhR-active compounds inhibit one or more of breast cancer cell proliferation, survival, migration/invasion, and metastasis. AhR-dependent mechanisms for the inhibition of breast cancer by AhR agonists are variable and include the downregulation of multiple genes/gene products such as CXCR4, MMPs, CXCL12, SOX4 and the modulation of microRNA levels. Some AhR ligands, such as aminoflavone, have been investigated in clinical trials for their anticancer activity against breast cancer. In contrast, several publications have reported that AhR agonists and antagonists enhance and inhibit mammary carcinogenesis, respectively, and differences between the anticancer activities of AhR agonists in breast cancer may be due in part to cell context and ligand structure. However, there are reports showing that the same AhR ligand in the same breast cancer cell line gives opposite results. These differences need to be resolved in order to further develop and take advantage of promising agents that inhibit mammary carcinogenesis by targeting the AhR.

In vitro and vivo study of tranilast protects from acute respiratory distress syndrome and early pulmonary fibrosis induced by smoke inhalation

BACKGROUND

Tranilast (N-[3＇,4＇-dimethoxycinnamoyl]-anthranilic acid) is an analog of a tryptophan metabolite. It was identified with anti-inflammatory and antifibrotic activities, and used in the treatment of a variety of diseases, such as anti - allergy, bronchial asthma, and hypertrophic scars. As a drug with few adverse reactions, tranilast has attracted great attention, but its application is limited due to the uncertainty of dosages and mechanisms. In this study, the protection effects of different doses of tranilast on smoke inhalation mediated lung injury on rats, and on the damage of three kinds of lung cells in vitro were investigated.

METHOD

In vivo, Sprague-Dawley rats were randomly divided into sham group, smoke group (rats were exposed to pine sawdust smoke three times, each time for 5 min), different doses of tranilast treatment group (doses were 100 mg/kg, 200 mg/kg and 300 mg/kg, ip.) and placebo group. After 1, 3 and 7 days, pulmonary function, pathologic injury by HE staining, cytokines and oxidative stress level by kits were determined. At 7days, lung fibrosis was assessed by Masson's trichrome staining and the level of hydroxyproline (HYP). In vitro, three kinds of lung cells from normal rats were isolated: type II alveolar epithelial cells (AT-II), pulmonary microvascular endothelial cells (PMVECs) and pulmonary fibroblasts (PFs). To investigate the potential effects of tranilast on cell proliferation, cell cycle and cytokine production of three kinds of lung cells exposed to smoke.

RESULTS

Compared with smoke group and placebo group, tranilast treatment significantly reduced histopathological changes (such as pulmonary hemorrhage, edema and inflammatory cell infiltration, etc.), significantly reduced histopathological score (p < 0.05), increased arterial oxygen partial pressure, and decreased the levels of IL-1β, TNF-α, TGF-β1 (p < 0.05), oxidative stress and the expression of nuclear transcription factor κB (NF-κB) smoke exposed rats (p < 0.01). In particular, the effect of 200 mg/kg dose was more prominent. In vitro, smoke induced AT-II and PMVECs apoptosis, improved PFs proliferation (p < 0.01), activity of SOD and decreased the content of MDA (p < 0.01). However, tranilast seems to be turning this trend well. The inflammatory factor IL-11β, TNF-α and TGF-β1, and the expression of NF-κB were significantly lower in the tranilast treatment than in the smoke group (p < 0.01).

CONCLUSION

This study indicates that tranilast had a protective effect on acute respiratory distress syndrome and early pulmonary fibrosis of rats in vivo. In addition, tranilast promotes proliferation of AT-II and PMVECs but inhibits PFs proliferation, down-regulates secretion of inflammatory cytokines and alleviates oxidative stress of AT-II, PMVECs and PFs after smoke stimuli in vitro.

Anthranilamides with quinoline and β-carboline scaffolds: design, synthesis, and biological activity

In the present study, we report the design and synthesis of novel amide-type hybrid molecules based on anthranilic acid and quinoline or β-carboline heterocyclic scaffolds. Three types of biological screenings were performed: (i) in vitro antiproliferative screening against a panel of solid tumor and leukemia cell lines, (ii) antiviral screening against several RNA viruses, and (iii) anti-quorum sensing screening using gram-negative Chromobacterium violaceum as the reporter strain. Antiproliferative screening revealed a high activity of several compounds. Anthranilamides 12 and 13 with chloroquine core and halogenated anthranilic acid were the most active agents toward diverse cancer cell lines such as glioblastoma, pancreatic adenocarcinoma, colorectal carcinoma, lung carcinoma, acute lymphoblastic, acute myeloid, chronic myeloid leukemia, and non-Hodgkin lymphoma, but also against noncancerous cell lines. Boc-protected analogs 2 and 3 showed moderate activities against the tested cancer cells without toxic effects against noncancerous cells. A nonhalogenated quinoline derivative 10 with N-benzylanthranilic acid residue was equally active as 12 and 13 and selective toward tumor cells. Chloroquine and quinoline anthranilamides 10-13 exerted pronounced antiviral effect against human coronaviruses 229E and OC43, whereas 12 and 13 against coronavirus OC43 (EC₅₀ values in low micromolar range; selectivity indices from 4.6 to > 10.4). Anthranilamides 14 and 16 with PQ core inhibited HIV-1 with EC₅₀ values of 9.3 and 14.1 µM, respectively. Compound 13 displayed significant anti-quorum/biofilm effect against the quorum sensing reporter strain (IC₅₀ of 3.7 μM) with no apparent bactericidal effect.

Cationic Channel TRPV2 Overexpression Promotes Resistance to Cisplatin-Induced Apoptosis in Gastric Cancer Cells

Gastric cancer (GC) is characterized by poor efficacy and modest clinical impact of current therapies, in which apoptosis evasion is relevant. Intracellular calcium homeostasis dysregulation is associated with apoptosis escaping, and aberrant expression of calcium regulator genes could promote GC drug resistance. Since we previously found a prognostic value for TRPV2 calcium channel expression in GC, we aimed to characterize the role of TRPV2 in cisplatin resistance. Using the TCGA-STAD dataset, we performed a differential gene expression analysis between GC samples in upper and lower tertiles of TRPV2 expression, and then through a gene set analysis, we highlighted the enriched ontology and canonical pathways. We used qRT-PCR to assess TRPV2 expression in three GC cell lines and flow cytometry to evaluate cisplatin-induced cell death rates. Calcium green-1-AM assay was used to estimate differences in intracellular Ca²⁺ concentrations after inhibition of TRPV2. We engineered AGS cell line to overexpress TRPV2 and used confocal microscopy to quantify its overexpression and localization and flow cytometry to evaluate their sensitivity to cisplatin. Consistent with our hypothesis, among enriched gene sets, we found a significant number of those involved in the regulation of apoptosis. Subsequently, we found an inverse correlation between TRPV2 expression and sensitivity to cisplatin in GC cell lines. Moreover, we demonstrated that inhibition of TRPV2 activity by tranilast blocks the efflux of Ca²⁺ ions and, in combination with cisplatin, induced a significant increase of apoptotic cells (p = 0.004). We also demonstrated that TRPV2 exogenous expression confers a drug-resistant phenotype, and that tranilast is able to revert this phenotype, restoring cisplatin sensitivity. Our findings consistently suggested that TRPV2 could be a potential target for overcoming cisplatin resistance by promoting apoptosis. Notably, our data are a prerequisite for the potential reposition of tranilast to the treatment of GC patients and anticipate the in vivo evaluation.

Anti-cancer effects of Tranilast: An update

Tranilast (TRN) or (N-3,4 -dimethoxy cinnamoyl]-anthranilic acid) is an analog of a tryptophan metabolite and is identified mainly as an anti-allergic agent with limited side effects. The anti-cancer effects of tranilast either alone or in combination with chemotherapeutic drugs have been evidenced in several pre-clinical studies. The main mechanism of action of tranilast includes targeting and modulation of various signaling and immune regulatory pathways including Transforming growth factor-beta (TGF-β), nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), phosphatidylinositol 3-kinase (PI3K), MAP-Kinase (MAPK), Protein kinase B (‎Akt/PKB), c-Jun N-terminal kinase, modulation of cancer stem cells, etc. Most of these pathways are involved in tumor proliferation, invasion, and metastasis and it is postulated that tranilast, with its low toxicity profile and high anti-carcinogenic abilities, can serve as a potential anti-tumorigenic agent. The main aim of this review is to provide updated information on the anti-cancer effects of tranilast and its significance as a therapeutic agent.

Design and synthesis of novel tranilast analogs: Docking, antiproliferative evaluation and in-silico screening of TGFβR1 inhibitors

The discovery of the antiproliferative potential of tranilast prompted additional studies directed at understanding the mechanisms of tranilast action. Its inhibitory effect on cell proliferation depends principally on the capacity of tranilast to interfere with transforming growth factor beta (TGFβR1) signaling. This work summarizes design, synthesis and biological evaluation of sixteen novel tranilast analogs on different tumors such as PC-3, HepG-2 and MCF-7 cell lines. The in vitro cytotoxicity was evaluated using MTT assay showed that, twelve compounds out of sixteen showed higher cytotoxic activities (IC₅₀'s 1.1-6.29 µM), than that of the reference standard, 5-FU (IC₅₀ 7.53 µM). The promising cytotoxic hits (4b, 7a, b and 14c-e), proved to be selective to cancer cells when their cytotoxicity's are examined on human normal cell line (WI-38). Then they are investigated for their possible mode of action as TGFβR1 inhibitors; remarkable inhibition of TGFβR1 by these hits was observed at the range of IC₅₀ 0.087-3.276 μM. The cell cycle analysis of the most potent TGFβR1 inhibitor, 4b revealed cell cycle arrest at G₂/M phase on prostate cancer cells. Additionally, it is clearly indicated apoptosis induction at Pre-G1 phase, this is substantiated by significant increase in the expression on the tumor suppressor gene, p53 and up regulation the level of apoptosis mediator, caspase-3. In addition, in silico study was performed for validating the physicochemical and ADME properties which revealed that, all compounds are orally bioavailable with no side effects complying with Lipinski rule. The proposed mode of action can be further explored on the light of molecular modeling simulation of the most potent compounds, 4b and 14e which were docked into the active sites of TGFβR1 to predict their affinities toward the receptor.

Lysozyme as the anti-proliferative agent to block the interaction between S100A6 and the RAGE V domain

In this report, using NMR and molecular modeling, we have studied the structure of lysozyme-S100A6 complex and the influence of tranilast [N-(3, 4-dimethoxycinnamoyl) anthranilic acid], an antiallergic drug which binds to lysozyme, on lysozyme-S100A6 and S100A6-RAGE complex formation and, finally, on cell proliferation. We have found that tranilast may block the S100A6-lysozyme interaction and enhance binding of S100A6 to RAGE. Using WST1 assay, we have found that lysozyme, most probably by blocking the interaction between S100A6 and RAGE, inhibits cell proliferation while tranilast may reverse this effect by binding to lysozyme. In conclusion, studies presented in this work, describing the protein-protein/-drug interactions, are of great importance for designing new therapies to treat diseases associated with cell proliferation such as cancers.

Tranilast enhances the effect of anticancer agents in osteosarcoma

Tranilast [N-(3′,4′-dimethoxycinnamoyl)-anthranilic acid], initially developed as an antiallergic drug, also exhibits a growth inhibitory effect on various types of cancer. Osteosarcoma is treated mainly with high-dose methotrexate, doxorubicin, cisplatin and ifosfamide; however, 20–30 % of patients cannot be cured of metastatic disease. We investigated whether tranilast enhances the anticancer effects of chemotherapeutic drugs and analyzed its mechanism of action in osteosarcomas. Tranilast inhibited proliferation of HOS, 143B, U2OS and MG-63 osteosarcoma cells in a dose-dependent manner, as well as enhancing the effects of cisplatin and doxorubicin. The average combination index at effect levels for tranilast in combination with cisplatin was 0.57 in HOS, 0.4 in 143B, 0.39 in U2OS and 0.51 in MG-63 cells. Tranilast and cisplatin synergistically inhibited the viability of osteosarcoma cells. In flow cytometric analysis, although tranilast alone did not induce significant apoptosis, the combination of tranilast and cisplatin induced early and late apoptotic cell death. Expression of cleaved caspase-3, cleaved poly(ADP-ribose) polymerase and p-H2AX was enhanced by tranilast in combination with cisplatin. Tranilast alone increased expression of p21 and Bim protein in a dose-dependent manner. Cell cycle analysis using flow cytometry demonstrated that the combination of tranilast and cisplatin increased the number of cells in the G2/M phase. Compared with cisplatin alone, the combination increased levels of phospho-cyclin-dependent kinase 1 (Y15). In the 143B xenograft model, tumor growth was significantly inhibited by combined tranilast and cisplatin compared with the controls, whereas cisplatin alone did not significantly inhibit tumor growth. In conclusion, tranilast has a cytostatic effect on osteosarcoma cells and enhances the effect of anticancer drugs, especially cisplatin. Enhanced sensitivity to cisplatin was mediated by increased apoptosis through G2/M arrest. Since tranilast has been clinically approved and has few adverse effects, clinical trials of osteosarcoma chemotherapy in combination with tranilast are expected.

Prior anti-CAFs break down the CAFs barrier and improve accumulation of docetaxel micelles in tumor

BACKGROUND

Abnormal expression of stromal cells and extracellular matrix in tumor stroma creates a tight barrier, leading to insufficient extravasation and penetration of therapeutic agents. Cancer-associated fibroblasts (CAFs) take on pivotal roles encouraging tumor progression.

METHOD

To surmount the refractoriness of stroma, we constructed a multi-targeting combined scenario of anti-CAFs agent tranilast and antitumor agent docetaxel micelles (DTX-Ms). Tranilast cut down crosstalk between tumor cells and stromal cells, ameliorated the tumor microenvironment, and enhanced the antiproliferation efficacy of DTX-Ms on cancer cells.

RESULTS

Diverse experiments demonstrated that tranilast enhanced DTX-Ms' antitumor effect in a two-stage pattern by CAFs ablation, tumor cell migration blocking, and metastasis inhibition. Along with activated CAFs decreasing in vivo, the two-stage therapy succeeded in reducing interstitial fluid pressure, normalizing microvessels, improving micelles penetration and retention, and inhibiting tumor growth and metastasis. Interestingly, tranilast alone failed to inhibit tumor growth in vivo, and it could only be used as an adjuvant medicine together with an antitumor agent.

CONCLUSION

Our proposed two-stage therapy offers a promising strategy to enhance antitumor effects by breaking down CAFs barrier and increasing micellar delivery efficiency.

Biological Activities, Health Benefits, and Therapeutic Properties of Avenanthramides: From Skin Protection to Prevention and Treatment of Cerebrovascular Diseases

Oat (Avena sativa) is a cereal known since antiquity as a useful grain with abundant nutritional and health benefits. It contains distinct molecular components with high antioxidant activity, such as tocopherols, tocotrienols, and flavanoids. In addition, it is a unique source of avenanthramides, phenolic amides containing anthranilic acid and hydroxycinnamic acid moieties, and endowed with major beneficial health properties because of their antioxidant, anti-inflammatory, and antiproliferative effects. In this review, we report on the biological activities of avenanthramides and their derivatives, including analogs produced in recombinant yeast, with a major focus on the therapeutic potential of these secondary metabolites in the treatment of aging-related human diseases. Moreover, we also present recent advances pointing to avenanthramides as interesting therapeutic candidates for the treatment of cerebral cavernous malformation (CCM) disease, a major cerebrovascular disorder affecting up to 0.5% of the human population. Finally, we highlight the potential of foodomics and redox proteomics approaches in outlining distinctive molecular pathways and redox protein modifications associated with avenanthramide bioactivities in promoting human health and contrasting the onset and progression of various pathologies. The paper is dedicated to the memory of Adelia Frison.

The Role of Desmoplasia and Stromal Fibroblasts on Anti-cancer Drug Resistance in a Microengineered Tumor Model

Introduction

Cancer associated fibroblasts (CAFs) are known to participate in anti-cancer drug resistance by upregulating desmoplasia and pro-survival mechanisms within the tumor microenvironment. In this regard, anti-fibrotic drugs (i.e., tranilast) have been repurposed to diminish the elastic modulus of the stromal matrix and reduce tumor growth in presence of chemotherapeutics (i.e., doxorubicin). However, the quantitative assessment on impact of these stromal targeting drugs on matrix stiffness and tumor progression is still missing in the sole presence of CAFs.

Methods

We developed a high-density 3D microengineered tumor model comprised of MDA-MB-231 (highly invasive breast cancer cells) embedded microwells, surrounded by CAFs encapsulated within collagen I hydrogel. To study the influence of tranilast and doxorubicin on fibrosis, we probed the matrix using atomic force microscopy (AFM) and assessed matrix protein deposition. We further studied the combinatorial influence of the drugs on cancer cell proliferation and invasion.

Results

Our results demonstrated that the combinatorial action of tranilast and doxorubicin significantly diminished the stiffness of the stromal matrix compared to the control. The two drugs in synergy disrupted fibronectin assembly and reduced collagen fiber density. Furthermore, the combination of these drugs, condensed tumor growth and invasion.

Conclusion

In this work, we utilized a 3D microengineered model to tease apart the role of tranilast and doxorubicin in the sole presence of CAFs on desmoplasia, tumor growth and invasion. Our study lay down a ground work on better understanding of the role of biomechanical properties of the matrix on anti-cancer drug efficacy in the presence of single class of stromal cells.

Safer approaches to therapeutic modulation of TGF-β signaling for respiratory disease

The transforming growth factor (TGF)-β cytokines play a central role in development and progression of chronic respiratory diseases. TGF-β overexpression in chronic inflammation, remodeling, fibrotic process and susceptibility to viral infection is established in the most prevalent chronic respiratory diseases including asthma, COPD, lung cancer and idiopathic pulmonary fibrosis. Despite the overwhelming burden of respiratory diseases in the world, new pharmacological therapies have been limited in impact. Although TGF-β inhibition as a therapeutic strategy carries great expectations, the constraints in avoiding compromising the beneficial pleiotropic effects of TGF-β, including the anti-proliferative and immune suppressive effects, have limited the development of effective pharmacological modulators. In this review, we focus on the pathways subserving deleterious and beneficial TGF-β effects to identify strategies for selective modulation of more distal signaling pathways that may result in agents with improved safety/efficacy profiles. Adverse effects of TGF-β inhibitors in respiratory clinical trials are comprehensively reviewed, including those of the marketed TGF-β modulators, pirfenidone and nintedanib. Precise modulation of TGF-β signaling may result in new safer therapies for chronic respiratory diseases.

Evaluation of Suppressive Effects of Tranilast on the Invasion/Metastasis Mechanism in a Murine Pancreatic Cancer Cell Line

OBJECTIVES

Numerous studies have investigated the mechanism of the antitumor effect of tranilast, well known as an antiallergic drug. Herein, we investigated the mechanism of the antitumor effects of tranilast using murine PAN 02 cell line.

METHODS

In an allograft mouse model, the number of metastatic sites in the liver was counted. Wound healing and chemoinvasion assay were performed to evaluate migration and invasive ability of PAN 02, respectively. Activities of matrix metalloproteinases (MMPs) were evaluated by gelatin zymography. The expression of cofactors in the activation of MMP-2 was assessed by immunohistochemical staining at the front of metastasis.

RESULTS

The number of metastatic sites was reduced in tranilast-treated groups. Migration ability and tumor invasiveness were significantly inhibited by tranilast in a dose-dependent manner. Gelatin zymography revealed inhibition of MMP-2 activity. Immunohistochemical staining showed remarkable attenuation of tissue inhibitor of metalloproteinase (TIMP-) 2 expression in tranilast-treated groups.

CONCLUSIONS

Tissue inhibitor of metalloproteinase 2 is necessary for MMP-2 activation with interaction between membrane type 1-MMP and proMMP-2. These results suggested that tranilast may inhibit MMP-2 activation through attenuating TIMP-2 expression, resulting in inhibition of tumor invasion and metastasis. Our results showed possibility of tranilast in clinical application for novel cancer therapy.

Characterization of the Kynurenine Pathway in CD8+ Human Primary Monocyte-Derived Dendritic Cells

The kynurenine (KYN) pathway (KP) is a major degradative pathway of the amino acid, L-tryptophan (TRP), that ultimately leads to the anabolism of the essential pyridine nucleotide, nicotinamide adenine dinucleotide. TRP catabolism results in the production of several important metabolites, including the major immune tolerance-inducing metabolite KYN, and the neurotoxin and excitotoxin quinolinic acid. Dendritic cells (DCs) have been shown to mediate immunoregulatory roles that mediated by TRP catabolism. However, characterization of the KP in human DCs has so far only been partly delineated. It is critical to understand which KP enzymes are expressed and which KP metabolites are produced to be able to understand their regulatory effects on the immune response. In this study, we characterized the KP in human monocyte-derived DCs (MDDCs) in comparison with the human primary macrophages using RT-PCR, high-pressure gas chromatography, mass spectrometry, and immunocytochemistry. Our results show that the KP is entirely expressed in human MDDC. Following activation of the KP using interferon gamma, MDDCs can mediate apoptosis of T _h cells in vitro. Understanding the molecular mechanisms regulating KP metabolism in MDDCs may provide renewed insight for the development of novel therapeutics aimed at modulating immunological effects and peripheral tolerance.

Finding New Tricks for Old Drugs: Tumoricidal Activity of Non-Traditional Antitumor Drugs

Chemotherapy, a traditional method, plays an important role in tumor therapy. Currently, common clinical antitumor drugs have several defects like poor efficacy, side effects, etc. Furthermore, developing new antitumor drugs takes a long time and requires many resources. Recent studies have found that oldies are newbies for the oncologist, such as flavonoid, metformin, aspirin, etc. These non-traditional antitumor drugs (NTADs) are widely used in management of non-cancer diseases, which gained FDA approval for treatment of patients. Increasingly, studies about antitumor action of NTADs have attracted many researchers' interests. A giant amount of studies showed a decrease in cancer incidence in NTAD-treated patients. Several reports outlined a direct inhibitory effect of NTADs on cancer cell growth and antitumoral actions. This review summarized the research progress on antitumor effects of ten NTADs. Retrospective and meta-analyses of trials also showed that these NTADs had preventive effects against cancer in vitro and in vivo. These drugs represent a promising option for cancer treatment, which have clear benefits including clinical safety, obvious curative effect, and saving medical and health resources. Judged from previous reports, future studies will yield valuable data about the profitable effects of these drugs. With a better understanding of its mechanisms of antitumor activity, NTADs may become available for combination with chemotherapy or targeted therapy in clinic.

Tranilast ameliorates cyclophosphamide-induced lung injury and nephrotoxicity

The world-wide increase in cancer incidence imposes a corresponding significant increase in the use of chemotherapeutic agents. Nephrotoxicity is a side effect frequently encountered with cyclophosphamide (CP), which is also well-known to cause acute and chronic lung toxicities. The current study focuses on the evaluation of the potential protective efficacy of tranilast against acute and subacute CP-induced lung and kidney injuries in male Swiss Albino mice. Intraperitoneal CP significantly impaired oxidant/anti-oxidant balance and increased inflammatory cell count in bronchoalveolar lavage fluid, serum creatinine, blood urea nitrogen (BUN), tumor necrosis factor-α (TNF-α) and lactate dehydrogenase (LDH) levels, with significant impairment of lung and kidney architectures. Tranilast taken orally for 8 and 14 days significantly enhanced mice anti-oxidant defense mechanisms; it increased lung and kidney SOD activity, GSH content and reduced lipid peroxidation. Tranilast significantly reduced serum creatinine and BUN. Furthermore, it decreased accumulation of inflammatory cells in the lungs. Serum TNF-α, LDH, total lung and kidney protein contents significantly declined as well. Histopathological examination revealed concomitant significant tissue recovery. Such results show a significant protective potential of tranilast against deleterious lung and kidney damage induced by CP, probably by enhancing host antioxidant defense mechanism, decreasing cytotoxicity, and decreasing expression of inflammatory cytokines.

Identification of drugs that restore primary cilium expression in cancer cells

The development of cancer is often accompanied by a loss of the primary cilium, a microtubule-based cellular protrusion that functions as a cellular antenna and that puts a break on cell proliferation. Hence, restoration of the primary cilium in cancer cells may represent a novel promising approach to attenuate tumor growth. Using a high content analysis-based approach we screened a library of clinically evaluated compounds and marketed drugs for their ability to restore primary cilium expression in pancreatic ductal cancer cells. A diverse set of 118 compounds stimulating cilium expression was identified. These included glucocorticoids, fibrates and other nuclear receptor modulators, neurotransmitter regulators, ion channel modulators, tyrosine kinase inhibitors, DNA gyrase/topoisomerase inhibitors, antibacterial compounds, protein inhibitors, microtubule modulators, and COX inhibitors. Certain compounds also dramatically affected the length of the cilium. For a selection of compounds (Clofibrate, Gefitinib, Sirolimus, Imexon and Dexamethasone) their ability to restore ciliogenesis was confirmed in a panel of human cancer cell line models representing different cancer types (pancreas, lung, kidney, breast). Most compounds attenuated cell proliferation, at least in part through induction of the primary cilium, as demonstrated by cilium removal using chloral hydrate. These findings reveal that several commonly used drugs restore ciliogenesis in cancer cells, and warrant further investigation of their antineoplastic properties.

Tranilast inhibits the function of cancer-associated fibroblasts responsible for the induction of immune suppressor cell types

Cancer-associated fibroblasts (CAFs) are the dominant stromal component in the tumour microenvironment (TME), playing critical roles in generation of pro-tumourigenic TME; however, their contribution to suppression of antitumour immune responses has not been fully understood. To elucidate the interaction between CAFs and immune suppressor cells, we examined whether inhibition of CAFs function would impair the induction of immune suppressor cell types in vitro. In this study, we applied an anti-allergic and antifibrotic agent tranilast, which is used clinically, and evaluated a potential of tranilast to serve as a CAFs inhibitor. CAFs that had been isolated from E.G7 or LLC1 tumour-bearing mice were cultured in the presence of tranilast, and thereafter, CAFs functions on the secretion of some soluble factors as well as the induction of immune suppressor cells were evaluated. As a result, tranilast inhibited the proliferation of CAFs and reduced the levels of stromal cell-derived factor-1, prostaglandin E2 and transforming growth factor-β1 from CAFs in a dose-dependent manner. On the other hand, tranilast exerted no inhibitory effects on immune cells at doses under 100 μm. The induction of regulatory T cells and myeloid-derived suppressor cells from their progenitor cells was suppressed in the medium that CAFs had been cultured in the presence of tranilast; however, these findings were not observed when those progenitor cells were cultured in the medium containing tranilast alone. These data demonstrate that tranilast inhibits CAFs function, which is responsible for the induction of immune suppressor cells, and possesses a potential to serve as a specific CAFs inhibitor.

Targeting mast cells tryptase in tumor microenvironment: a potential antiangiogenetic strategy

Angiogenesis is a complex process finely regulated by the balance between angiogenesis stimulators and inhibitors. As a result of proangiogenic factors overexpression, it plays a crucial role in cancer development. Although initially mast cells (MCs) role has been defined in hypersensitivity reactions and in immunity, it has been discovered that MCs have a crucial interplay on the regulatory function between inflammatory and tumor cells through the release of classical proangiogenic factors (e.g., vascular endothelial growth factor) and nonclassical proangiogenic mediators granule-associated (mainly tryptase). In fact, in several animal and human malignancies, MCs density is highly correlated with tumor angiogenesis. In particular, tryptase, an agonist of the proteinase-activated receptor-2 (PAR-2), represents one of the most powerful angiogenic mediators released by human MCs after c-Kit receptor activation. This protease, acting on PAR-2 by its proteolytic activity, has angiogenic activity stimulating both human vascular endothelial and tumor cell proliferation in paracrine manner, helping tumor cell invasion and metastasis. Based on literature data it is shown that tryptase may represent a promising target in cancer treatment due to its proangiogenic activity. Here we focused on molecular mechanisms of three tryptase inhibitors (gabexate mesylate, nafamostat mesylate, and tranilast) in order to consider their prospective role in cancer therapy.

Synergistic effects of tamoxifen and tranilast on VEGF and MMP-9 regulation in cultured human breast cancer cells

BACKGROUND

Vascular endothelial growth factor and matrix metalloproteinases are two important factors for angiogenesis associated with breast cancer growth and progression. The present study was aimed to examine the effects of tamoxifen and tranilast drugs singly or in combination on proliferation of breast cancer cells and also to evaluate VEGF and MMP-9 expression and VEGF secretion levels.

MATERIALS AND METHODS

Human breast cancer cell lines, MCF-7 and MDA-MB-231, were treated with tamoxifen and/or tranilast alone or in combination and percentage cell survival and proliferative activity were evaluated using LDH leakage and MTT assays. mRNA expression and protein levels were examined by real-time RT-PCR and ELISA assay, respectively.

RESULTS

LDH and MTT assays showed that the combined treatment of tamoxifen and tranilast resulted in a significant decrease in cell viability and cell proliferation compared with tamoxifen or tranilast treatment alone, with significant decrease in VEGF mRNA and protein levels. We also found that tamoxifen as a single agent rarely increased MMP-9 expression. A decrease in MMP-9 expression was seen after treatment with tranilast alone and in the combined treatment MMP-9 mRNA level was decreased.

CONCLUSIONS

This combination treatment can able to inhibit growth, proliferation and angiogenesis of breast cancer cells.

The aryl hydrocarbon receptor ligand omeprazole inhibits breast cancer cell invasion and metastasis

BACKGROUND

Patients with ER-negative breast tumors are among the most difficult to treat and exhibit low survival rates due, in part, to metastasis from the breast to various distal sites. Aryl hydrocarbon receptor (AHR) ligands show promise as antimetastatic drugs for estrogen receptor (ER)-negative breast cancer.

METHODS

Triple negative MDA-MB-231 breast cancer cells were treated with eight AHR-active pharmaceuticals including 4-hydroxtamoxifen, flutamide leflunomide, mexiletine, nimodipine, omeprazole, sulindac and tranilast, and the effects of these compounds on cell proliferation (MTT assay) and cell migration (Boyden chamber assay) were examined. The role of the AHR in mediating inhibition of MDA-MB-231 cell invasion was investigated by RNA interference (RNAi) and knockdown of AHR or cotreatment with AHR agonists. Lung metastasis of MDA-MB-231 cells was evaluated in mice administered cells by tail vein injection and prometastatic gene expression was examined by immunohistochemistry.

RESULTS

We showed that only the proton pump inhibitor omeprazole decreased MDA-MB-231 breast cancer cell invasion in vitro. Omeprazole also significantly decreased MDA-MB-231 cancer cell metastasis to the lung in a mouse model (tail vein injection), and in vitro studies showed that omeprazole decreased expression of at least two prometastatic genes, namely matrix metalloproteinase-9 (MMP-9) and C-X-C chemokine receptor 4 (CXCR4). Results of RNA interference studies confirmed that omeprazole-mediated downregulation of CXCR4 (but not MMP-9) was AHR-dependent. Chromatin immunoprecipitation assays demonstrated that omeprazole recruited the AHR to regions in the CXCR4 promoter that contain dioxin response elements (DREs) and this was accompanied by the loss of pol II on the promoter and decreased expression of CXCR4.

CONCLUSIONS

AHR-active pharmaceuticals such as omeprazole that decrease breast cancer cell invasion and metastasis may have important clinical applications for late stage breast cancer chemotherapy.

The role of inflammation in inflammatory breast cancer

Inflammatory breast cancer (IBC) is the most aggressive form of breast cancer. Despite extensive study, whether inflammation contributes to the tumorigenicity or aggressiveness of IBC remains largely unknown. In this chapter, we will review the potential role played by inflammation in IBC based on the results of in vitro, in vivo, and patient studies. Current evidence suggests that several major inflammatory signaling pathways are constitutively active in IBC and breast cancer. Among them, the NF-κB, COX-2, and JAK/STAT signaling systems seem to play a major role in the tumorigenesis of IBC. Inflammatory molecules such as interleukin-6, tumor necrosis factor alpha (TNF-α), and gamma interferon have been shown to contribute to malignant transformation in preclinical studies of IBC, while transforming growth factor-β, interleukins 8 and 1β, as well as TNF-α appear to play a role in proliferation, survival, epithelial-mesenchymal transition, invasion, and metastasis. In this chapter, we also describe work thus far involving inhibitors of inflammation in the development of prevention and treatment strategies for IBC.

Tranilast enhances the anti-tumor effects of tamoxifen on human breast cancer cells in vitro

Background

Tamoxifen is the most widely used anti-estrogen for the treatment of breast cancer. Studies show that the combination therapy with other substances that helps the activity of tamoxifen. The objective of this study was to evaluate the effect of tamoxifen when used in combination with tranilast on human breast cancer cells.

Results

Two MCF-7 and MDA-MB-231 human breast cancer cell lines were treated with tamoxifen and/or tranilast. The cell viability and cytotoxicity was assessed using MTT and LDH assays; the apoptotic effects were examined by TUNEL assay, acridine orange/ethidium bromide staining and DNA laddering, also the expression levels of bax and bcl-2 genes were detected by real-time RT-PCR. The mRNA expression of TGF-β ligands and receptors examined using real-time RT-PCR and TGF-β1 protein secretion levels were also evaluated by ELISA assay. Inhibitory effect of these drugs on invasion and metastasis were tested by wound healing and matrigel invasion assay.

We found that combination of these drugs led to a marked increase in growth and proliferation inhibition compared to either agent alone. Furthermore, bax and bcl-2 affected by tamoxifen and/or tranilast and resulted in a significant increase in bax and decrease in bcl-2 mRNA expression. In addition, treatment with tamoxifen and/or tranilast resulted in significant decreased in TGF-β1, 2, 3, TGF-βRI and II mRNA and TGF-β1 protein levels while TGF-βRIII mRNA level was increased and invasion was also inhibited.

Conclusions

These findings indicate that tranilast, by synergistic effect, enhances the activity of tamoxifen and the TGF-β pathway is a target for this combination therapy, therefore; we propose that this combined treatment may be suitable selection in prevention of breast cancer.

Tranilast binds to aβ monomers and promotes aβ fibrillation

The antiallergy and potential anticancer drug tranilast has been patented for treating Alzheimer's disease (AD), in which amyloid β-protein (Aβ) plays a key pathogenic role. We used solution NMR to determine that tranilast binds to Aβ40 monomers with ∼300 μM affinity. Remarkably, tranilast increases Aβ40 fibrillation more than 20-fold in the thioflavin T assay at a 1:1 molar ratio, as well as significantly reducing the lag time. Tranilast likely promotes fibrillation by shifting Aβ monomer conformations to those capable of seed formation and fibril elongation. Molecular docking results qualitatively agree with NMR chemical shift perturbation, which together indicate that hydrophobic interactions are the major driving force of the Aβ-tranilast interaction. These data suggest that AD may be a potential complication for tranilast usage in elderly patients.

Inhibition of transforming growth factor-β release from tumor cells reduces their motility associated with epithelial-mesenchymal transition

The high level of transforming growth factor‑β (TGF‑β) in tumor tissue, which is primarily released from tumor cells, helps maintain their metastatic nature and exacerbates the creation of a pro-tumor microenvironment. Although the strategy of targeting TGF‑β in cancer therapy has shown promise, its effects remain limited. In the present study, we focused on tumor cells as sources of TGF‑β release, and hypothesized that inhibition of their TGF‑β release could suppress their epithelial-mesenchymal transition (EMT)-associated metastatic nature and inactivate the induction of suppressor immune cells. To investigate this hypothesis, LLC1 cells, a mouse lung cancer cell line, were cultured with the TGF‑β release inhibitor tranilast and the motility of LLC1 cells was examined. Furthermore, to examine whether inhibition of TGF‑β release influences the induction of regulatory T (Treg) cells, spleen cells from normal mice were cultured in medium in which LLC1 cells had been cultured with tranilast. The results showed that tranilast inhibited the release of TGF‑β1 from LLC1 cells without affecting their proliferation. Inhibition of TGF‑β1 release suppressed the invasive activity of LLC1 cells, but enhanced their activity to adhere. mRNA levels of Slug and Twist were decreased in LLC1 cells, whereas levels of E‑cadherin were recovered. Treg cells were less frequently induced by medium in which LLC1 cells had been cultured with tranilast. Taken together, inhibition of TGF‑β1 release dampens the metastatic nature of LLC1 cells through the downregulation of EMT and possesses the possibility to improve antitumor immune responses through suppression of Treg cell induction. These findings provide a new rationale for development of TGF‑β‑targeted molecular immunotherapy against cancer.

Endoglin haploinsufficiency promotes fibroblast accumulation during wound healing through Akt activation

Accurate regulation of dermal fibroblast function plays a crucial role in wound healing. Many fibrotic diseases are characterized by a failure to conclude normal tissue repair and the persistence of fibroblasts inside lesions. In the present study we demonstrate that endoglin haploinsufficiency promotes fibroblast accumulation during wound healing. Moreover, scars from endoglin-heterozygous (Eng^+/−) mice show persisting fibroblasts 12 days after wounding, which could lead to a fibrotic scar. Endoglin haploinsufficiency results in increased proliferation and migration of primary cultured murine dermal fibroblasts (MDFs). Moreover, Eng^+/− MDF have diminished responses to apoptotic signals compared with control cells. Altogether, these modifications could explain the augmented presence of fibroblasts in Eng^+/− mice wounds. We demonstrate that endoglin expression regulates Akt phosphorylation and that PI3K inhibition abolishes the differences in proliferation between endoglin haploinsufficient and control cells. Finally, persistent fibroblasts in Eng^+/− mice wound co-localize with a greater degree of Akt phosphorylation. Thus, endoglin haploinsufficiency seems to promote fibroblast accumulation during wound healing through the activation of the PI3K/Akt pathway. These studies open new non-Smad signaling pathway for endoglin regulating fibroblast cell function during wound healing, as new therapeutic opportunities for the treatment of fibrotic wounds.

Breast cancer stem cells: new therapeutic approaches

SUMMARY Breast cancer stem cells are defined as a small subset of cells within a cancer that constitutes a reservoir of self-sustaining cells; they are low-dividing, have a reduced ability to undergo apoptosis and a higher ability of DNA repair, making them more resistant to conventional radiation and chemotherapy. The recent better understanding of the mechanisms of resistance to therapy related to stem cells has opened new scenarios and perspectives for therapeutic approaches. Some drugs active against breast cancer stem cells have been used in cancer therapy for years, other approaches are currently under clinical trials and many drugs are still in a preclinical phase. Only controlled clinical trials will answer the question whether or not these new therapeutical approaches alone or combined with the ongoing treatments significantly improve the outcome of breast cancer patients.

Aryl hydrocarbon receptor (AHR)-active pharmaceuticals are selective AHR modulators in MDA-MB-468 and BT474 breast cancer cells

Leflunomide, flutamide, nimodipine, mexiletine, sulindac, tranilast, 4-hydroxytamoxifen, and omeprazole are pharmaceuticals previously characterized as aryl hydrocarbon receptor (AHR) agonists in various cell lines and animal models. In this study, the eight AHR-active pharmaceuticals were investigated in highly aggressive aryl hydrocarbon (Ah)-responsive BT474 and MDA-MB-468 breast cancer cell lines, and their effects on AHR protein, CYP1A1 (protein and mRNA), CYP1B1 (mRNA), and cell migration were determined. 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) was used as a positive control. The AHR agonist activities of the pharmaceuticals depended on structure, response, and cell context. Most compounds induced one or more AHR-mediated responses in BT474 cells, whereas in Ah-responsive MDA-MB-468 cells effects of the AHR-active pharmaceuticals were highly variable. 4-Hydroxytamoxifen, mexiletine, and tranilast did not induce CYP1A1 in MDA-MB-468 cells; moreover, in combination with TCDD, mexiletine was a potent AHR antagonist, tranilast was a partial antagonist, and 4-hydroxytamoxifen also exhibited some AHR antagonist activity. Omeprazole and, to a lesser extent, sulindac and leflunomide were full and partial AHR agonists, respectively, in both breast cancer cell lines. These data indicate that the AHR-active pharmaceuticals are selective AHR modulators, and applications of these drugs for targeting the AHR must be confirmed by studies using the most relevant cell context.

Exploring anti-TGF-β therapies in cancer and fibrosis

Transforming growth factor-β (TGF-β) is a multifunctional cytokine, with important roles in maintaining tissue homeostasis. TGF-β signals via transmembrane serine/threonine kinase receptors and intracellular Smad transcriptional regulators. Perturbed TGF-β signaling has been implicated in a large variety of pathological conditions. Increased TGF-β levels have been found in patients with cancer, fibrosis, and systemic sclerosis, and were correlated with disease severity. In cancer, TGF-β mediates tumor invasion and metastasis by affecting both tumor cells and the tumor microenvironment including fibroblast activation and immune suppression. Furthermore, TGF-β is a strong stimulator of extracellular matrix deposition. On the basis of these observations, small molecule inhibitors of the TGF-β receptor kinases, neutralizing antibodies that interfere with ligand?receptor interactions, antisense oligonucleotides reducing TGF-β expression, and soluble receptor ectodomains that sequester TGF-β have been developed to intervene with excessive TGF-β signaling activity in the aforementioned disorders. Here, we review the current state of anti-TGF-β therapy in clinical trials.

Breast cancer stem-like cells are inhibited by a non-toxic aryl hydrocarbon receptor agonist

Background

Cancer stem cells (CSCs) have increased resistance to cancer chemotherapy. They can be enriched as drug-surviving CSCs (D-CSCs) by growth with chemotherapeutic drugs, and/or by sorting of cells expressing CSC markers such as aldehyde dehydrogenase-1 (ALDH). CSCs form colonies in agar, mammospheres in low-adherence cultures, and tumors following xenotransplantation in Scid mice. We hypothesized that tranilast, a non-toxic orally active drug with anti-cancer activities, would inhibit breast CSCs.

Methodology/Findings

We examined breast cancer cell lines or D-CSCs generated by growth of these cells with mitoxantrone. Tranilast inhibited colony formation, mammosphere formation and stem cell marker expression. Mitoxantrone-selected cells were enriched for CSCs expressing stem cell markers ALDH, c-kit, Oct-4, and ABCG2, and efficient at forming mammospheres. Tranilast markedly inhibited mammosphere formation by D-CSCs and dissociated formed mammospheres, at pharmacologically relevant concentrations. It was effective against D-CSCs of both HER-2+ and triple-negative cell lines. Tranilast was also effective in vivo, since it prevented lung metastasis in mice injected i.v. with triple-negative (MDA-MB-231) mitoxantrone-selected cells. The molecular targets of tranilast in cancer have been unknown, but here we demonstrate it is an aryl hydrocarbon receptor (AHR) agonist and this plays a key role. AHR is a transcription factor activated by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), polycyclic aromatic hydrocarbons and other ligands. Tranilast induced translocation of the AHR to the nucleus and stimulated CYP1A1 expression (a marker of AHR activation). It inhibited binding of the AHR to CDK4, which has been linked to cell-cycle arrest. D-CSCs expressed higher levels of the AHR than other cells. Knockdown of the AHR with siRNA, or blockade with an AHR antagonist, entirely abrogated the anti-proliferative and anti-mammosphere activity of tranilast. Thus, the anti-cancer effects of tranilast are AHR dependent.

Conclusion/Significance

We show that tranilast is an AHR agonist with inhibitory effects on breast CSCs. It is effective against CSCs of triple-negative breast cancer cells selected for anti-cancer drug resistance. These results suggest it might find applications in the treatment of breast cancer.

Tranilast treatment decreases cell growth, migration and inhibits colony formation of human breast cancer cells

In the treatment of breast cancer, although a wide of choice of drugs and treatment modalities are available, drug resistance or drug toxicity poses a considerable challenge. Tranilast is a well tolerated drug used in the treatment of allergic disorders. Previous works in various models have shown that tranilast has the potential to be used as an anti-cancer drug. Hence, in this study using human breast cancer cell lines BT-474 and MDA-MB-231, we studied the effect of tranilast on cell growth, migration and ability to prevent colony formation in vitro, properties that are relevant to a possible therapeutic effect in breast cancer. We found that tranilast inhibits the growth of both breast cancer cell lines. In the cell migration experiments, the tumor cells exhibit significantly slower wound closure after tranilast treatment, as well as reduced migration using an insert system. Downregulation of MRTF-A, a global cytoskeleton regulator was observed after tranilast treatment. Additionally, tranilast treatment increased levels of cleaved PARP in both cell lines tested indicating a stimulation of apoptosis. A significant reduction in colony size and number was observed in soft agar clonogenic assays in both cell lines after tranilast treatment. BT-474 cells were more responsive to tranilast treatment compared to MDA-MB-231 cells, suggesting a difference in modes of action, or sensitivity, possibly related to their different receptor status. Based on these changes in cancer cell lines, we conclude that tranilast exerts effects that set a rationale for future preclinical studies in animal models of breast cancer.