Tranilast inhibits the growth and metastasis of mammary carcinoma

Pharmacotherapy for Keloids and Hypertrophic Scars

Keloids (KD) and hypertrophic scars (HTS), which are quite raised and pigmented and have increased vascularization and cellularity, are formed due to the impaired healing process of cutaneous injuries in some individuals having family history and genetic factors. These scars decrease the quality of life (QOL) of patients greatly, due to the pain, itching, contracture, cosmetic problems, and so on, depending on the location of the scars. Treatment/prevention that will satisfy patients' QOL is still under development. In this article, we review pharmacotherapy for treating KD and HTS, including the prevention of postsurgical recurrence (especially KD). Pharmacotherapy involves monotherapy using a single drug and combination pharmacotherapy using multiple drugs, where drugs are administered orally, topically and/or through intralesional injection. In addition, pharmacotherapy for KD/HTS is sometimes combined with surgical excision and/or with physical therapy such as cryotherapy, laser therapy, radiotherapy including brachytherapy, and silicone gel/sheeting. The results regarding the clinical effectiveness of each mono-pharmacotherapy for KD/HTS are not always consistent but rather scattered among researchers. Multimodal combination pharmacotherapy that targets multiple sites simultaneously is more effective than mono-pharmacotherapy. The literature was searched using PubMed, Google Scholar, and Online search engines.

Interplay between Estrogen, Kynurenine, and AHR Pathways: An immunosuppressive axis with therapeutic potential for breast cancer treatment

Breast cancer is one of the most common malignancies among women worldwide. Estrogen exposure via endogenous and exogenous sources during a lifetime, together with environmental exposure to estrogenic compounds, represent the most significant risk factor for breast cancer development. As breast tumors establish, multiple pathways are deregulated. Among them is the aryl hydrocarbon receptor (AHR) signaling pathway. AHR, a ligand-activated transcription factor associated with the metabolism of polycyclic aromatic hydrocarbons and estrogens, is overexpressed in breast cancer. Furthermore, AHR and estrogen receptor (ER) cross-talk pathways have been observed. Additionally, the Tryptophan (Trp) catabolizing enzymes indolamine-2,3-dioxygenase (IDO) and tryptophan-2,3-dioxygenase (TDO) are overexpressed in breast cancer. IDO/TDO catalyzes the formation of Kynurenine (KYN) and other tryptophan-derived metabolites, which are ligands of AHR. Once KYN activates AHR, it stimulates the expression of the IDO enzyme, increases the level of KYN, and activates non-canonical pathways to control inflammation and immunosuppression in breast tumors. The interplay between E2, AHR, and IDO/TDO/KYN pathways and their impact on the immune system represents an immunosuppressive axis on breast cancer. The potential modulation of the immunosuppressive E2-AHR-IDO/TDO/KYN axis has aroused great expectations in oncotherapy. The present article will review the mechanisms implicated in generating the immunosuppressive axis E2-AHR-IDO/TDO/KYN in breast cancer and the current state of knowledge as a potential therapeutic target.

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.

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.

Aryl Hydrocarbon Receptor and Its Diverse Ligands and Functions: An Exposome Receptor

The aryl hydrocarbon receptor (AhR) is a transcriptional factor that regulates multiple functions following its activation by a variety of ligands, including xenobiotics, natural products, microbiome metabolites, and endogenous molecules. Because of this diversity, the AhR constitutes an exposome receptor. One of its main functions is to regulate several lines of defense against chemical insults and bacterial infections. Indeed, in addition to its well-established detoxication function, it has several functions at physiological barriers, and it plays a critical role in immunomodulation. The AhR is also involved in the development of several organs and their homeostatic maintenance. Its activity depends on the type of ligand and on the time frame of the receptor activation, which can be either sustained or transient, leading in some cases to opposite modes of regulations as illustrated in the regulation of different cancer pathways. The development of selective modulators and their pharmacological characterization are important areas of research. Expected final online publication date for the Annual Review of Pharmacology and Toxicology, Volume 62 is January 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

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.

Synthetic alkyl-ether-lipid promotes TRPV2 channel trafficking trough PI3K/Akt-girdin axis in cancer cells and increases mammary tumour volume

The Transient Receptor Potential Vanilloid type 2 (TRPV2) channel is highly selective for Ca2+ and can be activated by lipids, such as LysoPhosphatidylCholine (LPC). LPC analogues, such as the synthetic alkyl-ether-lipid edelfosine or the endogenous alkyl-ether-lipid Platelet Activating Factor (PAF), modulates ion channels in cancer cells. This opens the way to develop alkyl-ether-lipids for the modulation of TRPV2 in cancer. Here, we investigated the role of 2-Acetamido-2-Deoxy-l-O-Hexadecyl-rac-Glycero-3-PhosphatidylCholine (AD-HGPC), a new alkyl-ether-lipid (LPC analogue), on TRPV2 trafficking and its impact on Ca2+ -dependent cell migration. The effect of AD-HGPC on the TRPV2 channel and tumour process was further investigated using calcium imaging and an in vivo mouse model. Using molecular and pharmacological approaches, we dissected the mechanism implicated in alkyl-ether-lipids sensitive TRPV2 trafficking. We found that TRPV2 promotes constitutive Ca2+ entry, leading to migration of highly metastatic breast cancer cell lines through the PI3K/Akt-Girdin axis. AD-HGPC addresses the functional TRPV2 channel in the plasma membrane through Golgi stimulation and PI3K/Akt/Rac-dependent cytoskeletal reorganization, leading to constitutive Ca2+ entry and breast cancer cell migration (without affecting the development of metastasis), in a mouse model. We describe, for the first time, the biological role of a new alkyl-ether-lipid on TRPV2 channel trafficking in breast cancer cells and highlight the potential modulation of TRPV2 by alkyl-ether-lipids as a novel avenue for research in the treatment of metastatic cancer.

TRPV2: A Cancer Biomarker and Potential Therapeutic Target

The Transient Receptor Potential Vanilloid type-2 (TRPV2) channel exhibits oncogenicity in different types of cancers. TRPV2 is implicated in signaling pathways that mediate cell survival, proliferation, and metastasis. In leukemia and bladder cancer, the oncogenic activity of TRPV2 was linked to alteration of its expression profile. In multiple myeloma patients, TRPV2 overexpression correlated with bone tissue damage and poor prognosis. In prostate cancer, TRPV2 overexpression was associated with the castration-resistant phenotype and metastasis. Loss or inactivation of TRPV2 promoted glioblastoma cell proliferation and increased resistance to CD95-induced apoptotic cell death. TRPV2 overexpression was associated with high relapse-free survival in triple-negative breast cancer, whereas the opposite was found in patients with esophageal squamous cell carcinoma or gastric cancer. Another link was found between TRPV2 expression and either drug-induced cytotoxicity or stemness of liver cancer. Overall, these findings validate TRPV2 as a prime candidate for cancer biomarker and future therapeutic target.

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.

Accumulation of mechanical forces in tumors is related to hyaluronan content and tissue stiffness

Hyaluronan is abundant in the extracellular matrix of many desmoplastic tumors and determines in large part the tumor biochemical and mechanical microenvironment. Additionally, it has been identified as one of the major physiological barriers to the effective delivery of drugs to solid tumors and its targeting with the use of pharmaceutical agents has shown to decompress tumor blood vessels, and thus improve tumor perfusion and efficacy of cytotoxic drugs. In this study, we investigated the contribution of hyaluronan to the accumulation of mechanical forces in tumors. Using experimental data from two orthotopic breast tumor models and treating tumors with two clinically approved anti-fibrotic drugs (tranilast and pirfenidone), we found that accumulation of growth-induced, residual forces in tumors are associated with hyaluronan content. Furthermore, mechanical characterization of the tumors revealed a good correlation of the accumulated forces with the elastic modulus of the tissue. Our results provide important insights on the mechano-pathology of solid tumors and can be used for the design of therapeutic strategies that target hyaluronan.

Teucrium polium Extract Enhances the Anti-Angiogenesis Effect of Tranilast on Human Umbilical Vein Endothelial Cells

Purpose: Angiogenesis plays an important role in numerous pathophysiological events like cancer. As a result of this, tranilast as an anti-fibrotic drug induces the promising antitumor activities through the inhibition of angiogenesis. Further, Teucrium polium (TP) is a herbal medicine (family Lamaceae) with antitumor properties. This study was conducted to investigate the combination effects of tranilast and T. polium on human umbilical vein endothelial cells (HUVECs) viability and apoptotic genes expression. Methods: The HUVECs line was treated using different doses of tranilast and T. polium alone or their combination. The cell cytotoxicity was evaluated using MTT and LDH assays; apoptosis was examined using acridine orange/ethidium bromide staining, nitric oxide (NO) production was evaluated using Griess reaction and the expression of BAX and BCL-2 genes were detected using real-time RT-PCR. One-way analysis of variance (ANOVA) test was used to compare the data in different groups. Results: The survival rate of HUVECs was significantly reduced (p<0.05) in a dose dependent manner by tranilast and T. polium. However, T. polium and tranilast combination significantly (p<0.001) reduced cell viability and increased apoptotic cells as compared to each drug alone. Also, HUVECs treated with Tranilast / T. polium combination showed a reduced level of NO as regards to cells exposed only to Tranilast or T. polium (p<0.05). Furthermore, a significant increase in BAX and a decrease in BCL-2 mRNA expression were observed in combination group (p<0.001). Conclusion: T. polium synergistically increased the antiangiogenic effect of tranilast on in vitro angiogenic model of HUVECs.

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.

Tranilast-induced stress alleviation in solid tumors improves the efficacy of chemo- and nanotherapeutics in a size-independent manner

Accumulation of mechanical stresses during cancer progression can induce blood and lymphatic vessel compression, creating hypo-perfusion, hypoxia and interstitial hypertension which decrease the efficacy of chemo- and nanotherapies. Stress alleviation treatment has been recently proposed to reduce mechanical stresses in order to decompress tumor vessels and improve perfusion and chemotherapy. However, it remains unclear if it improves the efficacy of nanomedicines, which present numerous advantages over traditional chemotherapeutic drugs. Furthermore, we need to identify safe and well-tolerated pharmaceutical agents that reduce stress levels and may be added to cancer patients' treatment regimen. Here, we show mathematically and with a series of in vivo experiments that stress alleviation improves the delivery of drugs in a size-independent manner. Importantly, we propose the repurposing of tranilast, a clinically approved anti-fibrotic drug as stress-alleviating agent. Using two orthotopic mammary tumor models, we demonstrate that tranilast reduces mechanical stresses, decreases interstitial fluid pressure (IFP), improves tumor perfusion and significantly enhances the efficacy of different-sized drugs, doxorubicin, Abraxane and Doxil, by suppressing TGFβ signaling and expression of extracellular matrix components. Our findings strongly suggest that repurposing tranilast could be directly used as a promising strategy to enhance, not only chemotherapy, but also the efficacy of cancer nanomedicine.

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.

Effect of tranilast in comparison with beclomethasone in chronic murine model of asthma

AIM OF THE STUDY

The current investigation was taken to scrutinize the action of tranilast on the airway remodeling in chronic asthma in mice.

MATERIALS AND METHODS

Intraperitoneal injection of ovalbumin was applied to mice for sensitization and subsequent inhalation of 1% ovalbumin three times week for 10 weeks for challenge. Beclomethasone or tranilast were given daily for the 10 week challenge period. At the end of the study, lung weight index, total collagen content, bronchoalveolar lavage level of total and differential cell counts, interleukin-13, in addition to lung tissue nitrate/nitrite and transforming growth beta-1 were measured. Also, histological analysis was done.

RESULTS

Asthmatic mice demonstrated apparent fibrotic changes. Significant airway fibrosis was demonstrated by hyperplasia of goblet cells and thickening of airway epithelium, increased content of lung collagen, lung and bronchoalveolar lavage of transforming growth factor beta-1 and interleukin-13 mutually accompanied by reduction in nitrate/nitrite generation.

CONCLUSIONS

Beclomethasone influence on airway remodeling was mediated mainly via suppression of eosinophilic recruitment into the airways and reduction of interleukin-13 cytokine levels. Whereas, tranilast effects on airway remodeling was found to be mainly mediated via its inhibitory effect on transforming growth beta-1. Both beclomethasone and tranilast influence airway remodeling by different degrees and mechanisms.

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.

Molecular Profiling and Malignant Behavior Define Two Rat Mammary Tumor Cell Lines as a Relevant Experimental Model

Cancer cell lines have become a reliable tool in genetic and biochemical studies of breast cancer. Here, we described the behavior and novel molecular characterization of two cell lines derived from DMBA-induced rat mammary tumor, LA7 and RBA. LA7 cells have been identified as myoepithelial cells with stem cell properties, whereas the RBA cell line are epithelial cells that present mutational activated H-Ras, but are much less known. We evaluated the proliferation rate and molecular markers, several signaling pathways status related to proliferation, survival, inflammation, and apoptosis, as well as migration capacity, global DNA methylation levels, and stem cells populations. In fact, we found the A/T transversion in the c-Ha-Ras codon 61 as the activator mutation origin described in RBA cells. LA7 and RBA cells showed a high proliferation rate associated with overexpression of Cyclin D1, and resistance to apoptotic signals due to lack of expression of Bad. Moreover, neither of these two cell lines expressed steroid receptors, but they showed high migration capacity, all in accordance with an aggressive phenotype. We found global DNA methylation levels in LA7 and RBA cells lower than reference tissues analyzed, in addition to the presence of different stem cells populations in RBA cell line that differed in the expression of CD44 and CD24. These results revealed a malignant behavior associated with cancer stem cell phenotype. Since this profile is similar to a human triple-negative basal-like tumor, their extensive characterization presented herein increases their value as a good in vitro model. J. Cell. Biochem. 117: 2825-2834, 2016. © 2016 Wiley Periodicals, Inc.

Inhibitory Effects of Tranilast on Cytokine, Chemokine, Adhesion Molecule, and Matrix Metalloproteinase Expression in Human Corneal Fibroblasts Exposed to Poly(I:C)

Purpose/Aim: Viral infection of the cornea can result in inflammation and scarring and eventually cause blindness. Polyinosinic-polycytidylic acid [poly(I:C)], an analog of viral double-stranded RNA, induces the synthesis of various cytokines, chemokines, adhesion molecules, and matrix metalloproteinases (MMPs) in corneal fibroblasts. The effects of tranilast on the expression of these molecules in human corneal fibroblasts were examined.

MATERIALS AND METHODS

Human corneal fibroblasts were cultured with or without poly(I:C) or tranilast. The release of the proinflammatory cytokine interleukin (IL)-6 and of the chemokines IL-8 and monocyte chemotactic protein-1 (MCP-1) was measured with enzyme-linked immunosorbent assays. The expression of intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), MMP-1, and MMP-3 was evaluated by immunoblot or immunofluorescence analysis. The phosphorylation of mitogen-activated protein kinases (MAPKs), c-Jun (a component of the transcription factor AP-1), and IκB-α (an endogenous inhibitor of the transcription factor NF-κB) was examined by immunoblot analysis.

RESULTS

Tranilast inhibited in a concentration- and time-dependent manner the production of IL-6, IL-8, MCP-1, ICAM-1, VCAM-1, MMP-1, and MMP-3 by corneal fibroblasts exposed to poly(I:C). It also inhibited the poly(I:C)-induced phosphorylation of c-Jun and the MAPK JNK without affecting that of IκB-α or the MAPKs ERK and p38.

CONCLUSIONS

Tranilast inhibited proinflammatory cytokine, chemokine, adhesion molecule, and MMP expression in human corneal fibroblasts exposed to poly(I:C), with these effects likely being mediated by attenuation of JNK-AP-1 signaling. Tranilast might therefore be expected to limit immune cell infiltration and stromal degradation associated with viral infection of the cornea.

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.

Classical and non-classical proangiogenic factors as a target of antiangiogenic therapy in tumor microenvironment

Angiogenesis is sustained by classical and non-classical proangiogenic factors (PFs) acting in tumor microenvironment and these factors are also potential targets of antiangiogenic therapies. All PFs induce the overexpression of several signaling pathways that lead to migration and proliferation of endothelial cells contributing to tumor angiogenesis and survival of cancer cells. In this review, we have analyzed each PF with its specific receptor/s and we have summarized the available antiangiogenic drugs (e.g. monoclonal antibodies) targeting these PFs, some of these agents have already been approved, others are currently in development for the treatment of several human malignancies.

Exploring the interaction between the antiallergic drug, tranilast and human serum albumin: Insights from calorimetric, spectroscopic and modeling studies

The interaction of tranilast (TRN), an antiallergic drug with the main drug transporter in human circulation, human serum albumin (HSA) was studied using isothermal titration calorimetry (ITC), fluorescence spectroscopy and in silico docking methods. ITC data revealed the binding constant and stoichiometry of binding as (3.21 ± 0.23) × 10(6)M(-1) and 0.80 ± 0.08, respectively, at 25°C. The values of the standard enthalpy change (ΔH°) and the standard entropy change (ΔS°) for the interaction were found as -25.2 ± 5.1 kJ mol(-1) and 46.9 ± 5.4 J mol(-1)K(-1), respectively. Both thermodynamic data and modeling results suggested the involvement of hydrogen bonding, hydrophobic and van der Waals forces in the complex formation. Three-dimensional fluorescence data of TRN-HSA complex demonstrated significant changes in the microenvironment around the protein fluorophores upon drug binding. Competitive drug displacement results as well as modeling data concluded the preferred binding site of TRN as Sudlow's site I on HSA.

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.

Role of TGFβ in regulation of the tumor microenvironment and drug delivery (review)

Deregulation of cell signaling homeostasis is a predominant feature of cancer initiation and progression. Transforming growth factor β (TGFβ) is a pleiotropic cytokine, which regulates numerous biological processes of various tissues in an autocrine and paracrine manner. Aberrant activity of TGFβ signaling is well known to play dual roles in cancer, depending on tumor stage and cellular context. The crucial roles of TGFβ in modulating the tumor microenvironment, its contribution to the accumulation of mechanical forces within the solid constituents of a tumor and its effects on the effective delivery of drugs are also becoming increasingly clear. In this review, we discuss the latest advances in the efforts to unravel the effects of TGFβ signaling in various components of the tumor microenvironment and how these influence the generation of forces and the efficacy of drugs. We also report the implications of tumor mechanics in cancer therapy and the potential usage of anti-TGFβ agents to enhance drug delivery and augment existing therapeutic approaches. These findings provide new insights towards the significance of targeting TGFβ pathway to enhance personalized tumor treatment.

Tranilast: a review of its therapeutic applications

Tranilast (N-[3',4'-dimethoxycinnamoyl]-anthranilic acid) is an analog of a tryptophan metabolite. Initially, tranilast was identified as an anti-allergic agent, and used in the treatment of inflammatory diseases, such as bronchial asthma, atypical dermatitis, allergic conjunctivitis, keloids and hypertrophic scars. Subsequently, the results showed that it could be also effective in the management of a wide range of conditions. The beneficial effects of tranilast have also been seen in a variety of disease states, such as fibrosis, proliferative disorders, cancer, cardiovascular problems, autoimmune disorders, ocular diseases, diabetes and renal diseases. Moreover, several trials have shown that it has very low adverse effects and it is generally well tolerated by patients. In this review, we have attempted to accurately summarize previously published studies relating to the use of tranilast for a range of disorders and discuss the drug's possible mode of action. The major mode of the drug's efficacy appears to be the suppression of the expression and/or action of the TGF-β pathway, but the drug affects other factors as well. The findings presented in this review demonstrate the potential of tranilast for the control of a vast array of pathological situations, furthermore, it is a prescribed drug without severe side effects.

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 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.

Activation of aryl hydrocarbon receptor (ahr) by tranilast, an anti-allergy drug, promotes miR-302 expression and cell reprogramming

MiR-302 has been shown to regulate pluripotency genes and help somatic cell reprogramming. Thus, promotion of endogenous miR-302 expression could be a desirable way to facilitate cell reprogramming. By using a luciferase reporter system of the miR-302 promoter, we screened and found that an anti-allergy drug, tranilast, could significantly promote miR-302 expression. Further experiments revealed that two aryl hydrocarbon receptor (AhR) binding motifs on the miR-302 promoter are critical and that activation of AhR is required for tranilast-induced miR-302 expression. Consistently, not only tranilast but other AhR agonists promoted miR-302 expression. Furthermore, the activation of AhR facilitated cell reprogramming in a miR-302-dependent way. These results elucidate that miR-302 expression can be regulated by AhR and thus provide a strategy for promoting somatic cell reprogramming by AhR ligands.

Curcumin improves the therapeutic efficacy of Listeria(at)-Mage-b vaccine in correlation with improved T-cell responses in blood of a triple-negative breast cancer model 4T1

Success of cancer vaccination is strongly hampered by immune suppression in the tumor microenvironment (TME). Interleukin (IL)-6 is particularly and highly produced by triple-negative breast cancer (TNBC) cells, and has been considered as an important contributor to immune suppression in the TME. Therefore, we hypothesized that IL-6 reduction may improve efficacy of vaccination against TNBC cancer through improved T-cell responses. To prove this hypothesis, we investigated the effect of curcumin, an inhibitor of IL-6 production, on vaccination of a highly attenuated Listeria monocytogenes (Listeria^at), encoding tumor-associated antigens (TAA) Mage-b in a TNBC model 4T1. Two therapeutic vaccination strategies with Listeria^at-Mage-b and curcumin were tested. The first immunization strategy involved all Listeria^at-Mage-b vaccinations and curcumin after tumor development. As curcumin has been consumed all over the world, the second immunization strategy involved curcumin before and all therapeutic vaccinations with Listeria^at-Mage-b after tumor development. Here, we demonstrate that curcumin significantly improves therapeutic efficacy of Listeria^at-Mage-b with both immunization strategies particularly against metastases in a TNBC model (4T1). The combination therapy was slightly but significantly more effective against the metastases when curcumin was administered before compared to after tumor development. With curcumin before tumor development in the combination therapy, the production of IL-6 was significantly decreased and IL-12 increased by myeloid-derived suppressor cells (MDSC), in correlation with improved CD4 and CD8 T-cell responses in blood. Our study suggests that curcumin improves the efficacy of Listeria^at-Mage-b vaccine against metastases in TNBC model 4T1 through reversal of tumor-induced immune suppression.

This study is focused on improving cancer vaccination by reducing immune suppression. Here we demonstrate that curcumin improves vaccine efficacy of Listeria-Mage-b by converting myeloid-derived suppressor cells into an immune stimulating phenotype, that is, through reducing IL-6 and increasing IL-12 production, in correlation with improved T cell responses and a dramatic reduction in the number of metastases. The novel results of this study may be a platform for improvement of other cancer vaccines by curcumin.

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.

Uterine leiomyoma: available medical treatments and new possible therapeutic options

CONTEXT

Uterine leiomyomas (fibroids or myomas) are benign tumors of the uterus and are clinically apparent in up to 25% of reproductive-age women. Heavy or abnormal uterine bleeding, pelvic pain or pressure, infertility, and recurrent pregnancy loss are generally associated with leiomyoma. Although surgical and radiological therapies are frequently used for the management of this tumor, medical therapies are considered the first-line treatment of leiomyoma.

EVIDENCE ACQUISITION AND SYNTHESIS

A review was conducted of electronic and print data comprising both original and review articles on pathophysiology and medical treatments of uterine leiomyoma retrieved from the PubMed or Google Scholar database up to June 2012. These resources were integrated with the authors' knowledge of the field.

CONCLUSION

To date, several pathogenetic factors such as genetic factors, epigenetic factors, estrogens, progesterone, growth factors, cytokines, chemokines, and extracellular matrix components have been implicated in leiomyoma development and growth. On the basis of current hypotheses, several medical therapies have been investigated. GnRH agonist has been approved by US Food and Drug Administration for reducing fibroid volume and related symptoms. In addition, the FDA also approved an intrauterine device, levonorgestrel-releasing intrauterine system (Mirena), for additional use to treat heavy menstrual bleeding in intrauterine device users only. Currently, mifepristone, asoprisnil, ulipristal acetate, and epigallocatechin gallate have been shown to be effective for fibroid regression and symptomatic improvement which are all in clinical trial. In addition, some synthetic and natural compounds as well as growth factor inhibitors are now under laboratory investigation, and they could serve as future therapeutic options.

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.

Biocompatibility and antifibrotic effect of UV-cross-linked hyaluronate as a release-system for tranilast after trabeculectomy in a rabbit model--a pilot study

PURPOSE

To analyze the release kinetics and the clinical and histological effects of UV-cross-linked hyaluronic acid as a release-system for the transforming growth factor β-2 antagonist tranilast with anti-phlogistic properties on intraocular pressure after trabeculectomy in an aggressive scarring animal model.

METHODS

Hyaluronate acid was UV-cross linked and loaded with tranilast. The release of tranilast into a buffered salt solution was assessed spectrophotometrically. Glaucoma filtration surgery, similar to that performed in clinical practice, was performed on chinchilla rabbits. The rabbits were divided in 3 groups. (Group A: trabeculectomy alone, group B: trabeculectomy with a cross-linked hyaluronic acid gel preparation and group C: trabeculectomy with cross-linked hyaluronic gel preparation mixed with tranilast). Antifibrotic efficacy was established by clinical response and histologic examination.

RESULTS

The cross-linked gels released tranilast for up to 26 h. The release plotted as a function of the square root of time was consistent with a largely diffusion-controlled release system. Both the gel preparation alone and the gel preparation mixed with tranilast were well tolerated in vivo. No adverse effects such as inflammation, corneal toxicity or blurring of the optical media were observed. The intraocular pressure reached preoperative levels within 9 days after surgery in control animals and group B, but remained significantly reduced (p = 0.00016) in the group with tranilast until day 22.

CONCLUSIONS

The data of this pilot study suggest that the intraoperative application of UV-crossed linked hyaluronic acid used as a slow release system for tranilast may improve the surgical outcome of glaucoma filtration surgery.

Neuropilin-1 is expressed by breast cancer stem-like cells and is linked to NF-κB activation and tumor sphere formation

Cancer stem cells (CSCs) initiate tumors and have a high resistance to conventional cancer therapy. Tranilast is an orally active drug of low toxicity that exerts inhibitory effects on breast CSCs. This appears to depend on its aryl hydrocarbon receptor (AHR) agonistic activity, but this receptor has diverse functions and it is unclear how CSCs are inhibited. CSCs generate tumor spheres in low-adherence cultures, and we employed the mammosphere-forming assay as a functional test for breast CSCs. Because NF-κB has a key role in mammosphere formation and CSC-mediated tumor initiation, we examined that pathway. We also examined the role of neuropilin-1 (Nrp1), which is a growth factor coreceptor linked to the tumorigenicity of some CSCs. We found that tranilast concurrently suppressed mammosphere formation, Nrp1 expression and constitutive NF-κB activation. Flow cytometric analysis revealed that a subpopulation of breast cancer cells bearing breast CSC markers also expressed Nrp1. A blocking anti-Nrp1 antibody suppressed mammosphere formation. We examined whether there was a link between Nrp1 and NF-κB activation. The siRNA knockdown of Nrp1 severely suppressed NF-κB activation and mammosphere formation. The phosphorylation of Akt and ERK1/2 was also reduced, but to a lesser extent. We conclude that Nrp1 plays a key role in mammosphere formation and this activity is linked to NF-κB activation. Thus, Nrp1 might be a target for therapy against breast CSCs, and the anticancer drug tranilast suppresses its expression.

Activation of the aryl hydrocarbon receptor by TCDD inhibits mammary tumor metastasis in a syngeneic mouse model of breast cancer

Treatment with aryl hydrocarbon receptor (AhR) agonists can slow or reverse the growth of primary mammary tumors in rodents, which has fostered interest in developing selective AhR modulators for treatment of breast cancer. However, the major goal of breast cancer therapy is to inhibit metastasis, the primary cause of mortality in women with this disease. Studies conducted using breast cancer cell lines have demonstrated that AhR agonists suppress proliferation, invasiveness, and colony formation in vitro; however, further exploration using in vivo models of metastasis is warranted. To test the effect of AhR activation on metastasis, 4T1.2 mammary tumor cells were injected into the mammary gland fat pad of syngeneic Balb/c mice treated with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Primary tumor growth was monitored for 4 weeks, at which time metastasis was determined. TCDD treatment suppressed metastasis by approximately 50%, as measured both in the lung and in mammary glands at sites distant from the primary tumor. Primary tumor growth was not suppressed by TCDD exposure nor was proliferation of 4T1.2 cells affected by TCDD treatment in vitro. Taken together, these results suggest that the protective effect of AhR activation was selective for the metastatic process and not simply the result of a direct decrease in tumor cell proliferation or survival at the primary site. These observations in immunologically intact animals warrant further investigation into the mechanism of the protective effects of AhR activation and support the promise for use of AhR modulators to treat breast cancer.

Metal-free imidazolium salts inhibit the growth of hepatocellular carcinoma in a mouse model

Imidazolium salts (IMSs) are precursors to N-heterocyclic carbenes (NHCs), which are routinely used as ligands or organo-catalysts in synthetic chemistry. We recently identified several IMSs as anti-fibrotic agents in liver fibrosis, which often has a consequence in the oncogenesis of hepatocellular carcinoma (HCC). Here, we investigate the potential anti-tumor property of three IMSs (named IBN-1, IBN-9, and DPIM) in HCC cell lines and in a xenograft mouse model. Our results showed that both IBN-1 and IBN-9 significantly inhibited the cell proliferation and arrested HCC cells in the G1-phase, whereas DPIM did not have any anti-tumor activity. When tested in a Huh7 HCC xenograft mouse model, IBN-1 reduced the tumor volume by 31% (P<0.05), however accompanied by a 9% loss in body weight (P<0.005), suggesting a general toxicity. In contrast, IBN-9 significantly reduced the tumor volume by 45% (P<0.05) and 60% (P<0.01) at doses of 0.6 and 1.5 g/l in drinking water, respectively, without any loss in body weight. Our in vitro and in vivo data suggested that IBN-1 and IBN-9 inhibited the growth of HCC by suppressing the expression of Survivin and Cyclin-dependent kinases. The current study provides a proof of concept for using the metal-free IMSs to develop novel anti-cancer agents.

Tranilast modulates fibrosis, epithelial-mesenchymal transition and peritubular capillary injury in unilateral ureteral obstruction rats

AIM

Tranilast is an anti-allergic compound suppressing transforming growth factor-beta 1 (TGF-β1) induced fibrosis. This study evaluated the efficacy of tranilast to attenuate renal fibrosis induced by unilateral ureteral obstruction (UUO) in rats in relation to epithelial-mesenchymal transition (EMT) and peritubular capillary injury.

METHODS

Rats were divided into four groups: UUO with vehicle or tranilast and sham operation with vehicle or tranilast. Tranilast (400 mg/kg/day) was administrated to rats for 7 and 14 days after UUO.

RESULTS

Fibrosis and tubular injuries were attenuated in UUO kidneys with tranilast (Tr-UUO kidneys) compared with UUO kidneys with vehicle (V-UUO kidneys). Decreased E-cadherin and increased vimentin expression in the tubular epithelium and Snail expression in V-UUO kidneys were also attenuated in Tr-UUO kidneys in which heparan sulfate proteoglycan in the tubular basement membrane was preserved and matrix metalloproteinase-2 expression was attenuated. Increased TGF-β1 and phospho-Smad2 expression and increased numbers of myofibroblasts and macrophages in V-UUO kidneys were attenuated by tranilast. Decreased VE-cadherin expression and cytoplasmic swelling of the endothelium of peritubular capillaries that occurred in V-UUO kidneys was prevented by tranilast.

CONCLUSIONS

Tranilast modulates fibrogenesis by reducing EMT, preventing disintegration of the tubular basement membrane, and reducing peritubular capillary injury in UUO kidneys.

Neuropilin-1 exerts co-receptor function for TGF-beta-1 on the membrane of cancer cells and enhances responses to both latent and active TGF-beta

Neuropilin (Nrp)-1 and Nrp-2 are multifunctional proteins frequently expressed by cancer cells and contribute to tumor progression by mechanisms that are not well understood. They are co-receptors for vascular endothelial growth factor and class 3 semaphorins, but recently we found that Nrp1 also binds latent and active transforming growth factor (TGF)-β1, and activates the latent form latency-associated peptide (LAP)-TGF-β1. Here, we report that Nrp1 has affinity for TGF-β receptors TβRI and TβRII, the signaling TGF-β receptors, as well as TβRIII (betaglycan), as determined in binding assays, pull down assays and confocal microscopy. Nrp1 had a higher affinity for TβRI than TβRII and could form a complex with these receptors. In breast cancer cells, Nrp1 and TβRI cointernalized in the presence of TGF-β1. Nrp1 acted as a TGF-β co-receptor by augmenting canonical Smad2/3 signaling. Importantly, Nrp-positive cancer cells, unlike negative cells, were able to activate latent TGF-β1 and respond. We examined two other membrane proteins that bind LAP-TGF-β, i.e. an RGD-binding integrin (αvβ3) and Glycoprotein A repetitions predominant (CLRRC32). RGD-binding integrins are frequently expressed by cancer cells, and glycoprotein A repetitions predominant is expressed by activated regulatory T cells that appear linked to poor tumor immunity. In vitro, these receptors did not activate LAP-TGF-β1, but subsequent addition of Nrp1 activated the cytokine. Thus, Nrp1 might collaborate with other latent TGF-β receptors in TGF-β capture and activation. We also show that Nrp2 has activities similar to Nrp1. We conclude that Nrp1 is a co-receptor for TGF-β1 and augments responses to latent and active TGF-β. Since TGF-β promotes metastasis this is highly relevant to cancer biology.

Identification of retinoic acid in a high content screen for agents that overcome the anti-myogenic effect of TGF-beta-1

BACKGROUND

Transforming growth factor beta 1 (TGF-β1) is an inhibitor of muscle cell differentiation that is associated with fibrosis, poor regeneration and poor function in some diseases of muscle. When neutralizing antibodies to TGF-β1 or the angiotensin II inhibitor losartan were used to reduce TGF-β1 signaling, muscle morphology and function were restored in mouse models of Marfan Syndrome and muscular dystrophy. The goal of our studies was to identify additional agents that overcome the anti-myogenic effect of TGF-β1.

METHODOLOGY/PRINCIPAL FINDINGS

A high-content cell-based assay was developed in a 96-well plate format that detects the expression of myosin heavy chain (MHC) in C2C12 cells. The assay was used to quantify the dose-dependent responses of C2C12 cell differentiation to TGF-β1 and to the TGF-β1 Type 1 receptor kinase inhibitor, SB431542. Thirteen agents previously described as promoting C2C12 differentiation in the absence of TGF-β1 were screened in the presence of TGF-β1. Only all-trans retinoic acid and 9-cis retinoic acid allowed a maximal level of C2C12 cell differentiation in the presence of TGF-β1; the angiotensin-converting enzyme inhibitor captopril and 10 nM estrogen provided partial rescue. Vitamin D was a potent inhibitor of retinoic acid-induced myogenesis in the presence of TGF-β1. TGF-β1 inhibits myoblast differentiation through activation of Smad3; however, retinoic acid did not inhibit TGF-β1-induced activation of a Smad3-dependent reporter gene in C2C12 cells.

CONCLUSIONS/SIGNIFICANCE

Retinoic acid alleviated the anti-myogenic effect of TGF-β1 by a Smad3-independent mechanism. With regard to the goal of improving muscle regeneration and function in individuals with muscle disease, the identification of retinoic acid is intriguing in that some retinoids are already approved for human therapy. However, retinoids also have well-described adverse effects. The quantitative, high-content assay will be useful to screen for less-toxic retinoids or combinations of agents that promote myoblast differentiation in the presence of TGF-β1.

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.

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

The malignant transformation of breast epithelium involves a number of cellular pathways, including those dependent on signaling from TGF beta. Tranilast [N-(3, 4-dimethoxycinnamonyl)-anthranilic acid] is a drug that is used in Japan to control allergic disorders in patients, and its mechanism of action involves TGF beta. In view of the multiple roles of TGF beta in tumor progression, we hypothesized in this study that tranilast impacts cell proliferation, apoptosis, and migration. Using the mouse breast cancer cell line 4T1, our studies showed that tranilast increases AKT1 phosphorylation and decreases ERK1/2 phosphorylation. Alterations in the cell cycle mediators' cyclin D1, p27, cyclin A, pRB, cyclin B, and Cdc2 were observed after exposure to tranilast, favoring cell arrest beyond the G1/S phase. Tranilast reduced tumor cell proliferation even when it was amplified by exogenous TGF beta. TGF beta-neutralizing antibody did not cause a significant decrease in cell proliferation. Tranilast treatment upregulates p53, induces PARP cleavage in vitro, consistent with a promotion of tumor cell apoptosis. TGF beta-neutralizing antibody downregulates endoglin and matrix metalloproteinases (MMP)-9 levels in vitro indicating that the tranilast effect is mediated through TGF beta modulation. Tranilast treatment results in the inhibition of cell migration and invasion. Western blot analysis of tumor lysates from tranilast-treated mice shows decreased levels of TGF beta1, endoglin, and significantly higher levels of p53 and cleaved PARP. Cleaved caspase 3 expression is significantly elevated in tranilast-treated mouse breast tumors. To conclude, tranilast induces cellular and molecular changes in murine breast cancer that can be exploited in preclinical therapeutic trials.

Connection between inflammation and carcinogenesis in gastrointestinal tract: Focus on TGF-β signaling

Inflammation is a primary defense process against various extracellular stimuli, such as viruses, pathogens, foods, and environmental pollutants. When cells respond to stimuli for short periods of time, it results in acute or physiological inflammation. However, if the stimulation is sustained for longer time or a pathological state occurs, it is known as chronic or pathological inflammation. Several studies have shown that tumorigenesis in the gastrointestinal (GI) tract is closely associated with chronic inflammation, for which abnormal cellular alterations that accompany chronic inflammation such as oxidative stresses, gene mutations, epigenetic changes, and inflammatory cytokines, are shared with carcinogenic processes, which forms a critical cross-link between chronic inflammation and carcinogenesis. Transforming growth factor (TGF)-β is a multi-potent cytokine that plays an important role in regulation of cell growth, apoptosis and differentiation. Most importantly, TGF-β is a strong anti-inflammatory cytokine that regulates the development of effector cells. TGF-β has a suppressive effect on carcinogenesis under normal conditions by inhibiting abnormal cell growth, but on the other hand, many GI cancers originate from uncontrolled cell growth and differentiation by genetic loss of TGF-β signaling molecules or perturbation of TGF-β adaptors. Once a tumor has developed, TGF-β exerts a promoting effect on the tumor itself and stromal cells to enhance cell growth, alter the responsiveness of tumor cells to stimulate invasion and metastasis, and inhibited immune surveillance. Therefore, novel development of therapeutic agents to inhibit TGF-β-induced progression of tumor and to retain its growth inhibitory activities, in addition to anti-inflammatory actions, could be useful in oncology. In this review, we discuss the role of TGF-β in inflammation and carcinogenesis of the GI tract related to abnormal TGF-β signaling.