Curcumin suppresses HIF1A synthesis and VEGFA release in pituitary adenomas

Ferroptosis-Regulated Natural Products and miRNAs and Their Potential Targeting to Ferroptosis and Exosome Biogenesis

Ferroptosis, which comprises iron-dependent cell death, is crucial in cancer and non-cancer treatments. Exosomes, the extracellular vesicles, may deliver biomolecules to regulate disease progression. The interplay between ferroptosis and exosomes may modulate cancer development but is rarely investigated in natural product treatments and their modulating miRNAs. This review focuses on the ferroptosis-modulating effects of natural products and miRNAs concerning their participation in ferroptosis and exosome biogenesis (secretion and assembly)-related targets in cancer and non-cancer cells. Natural products and miRNAs with ferroptosis-modulating effects were retrieved and organized. Next, a literature search established the connection of a panel of ferroptosis-modulating genes to these ferroptosis-associated natural products. Moreover, ferroptosis-associated miRNAs were inputted into the miRNA database (miRDB) to bioinformatically search the potential targets for the modulation of ferroptosis and exosome biogenesis. Finally, the literature search provided a connection between ferroptosis-modulating miRNAs and natural products. Consequently, the connections from ferroptosis-miRNA-exosome biogenesis to natural product-based anticancer treatments are well-organized. This review sheds light on the research directions for integrating miRNAs and exosome biogenesis into the ferroptosis-modulating therapeutic effects of natural products on cancer and non-cancer diseases.

Reduction-responsive worm-like nanoparticles for synergistic cancer chemo-photodynamic therapy

Chemo-photodynamic therapy shows great potential for cancer treatment. However, the rational integration of chemotherapeutic agents and photosensitizers to construct an intelligent nanoplatform with synergistic therapeutic effect is still a great challenge. In this work, curcumin-loaded reduction-responsive prodrug nanoparticles of new indocyanine green (Cur@IR820-ss-PEG) were developed for synergistic cancer chemo-photodynamic therapy. Cur@IR820-ss-PEG exhibit high drug loading content and special worm-like morphology, contributing to their efficient cellular uptake. Due to the presence of the disulfide bond between IR820 and PEG, Cur@IR820-ss-PEG display reduction responsive drug release behaviors. The efficient cellular uptake and reduction triggered drug release of Cur@IR820-ss-PEG lead to their enhanced in vitro cytotoxicity against 4T1cells as compared to the mixture of IR820 and curcumin (IR820/Cur) under laser irradiation. Besides, Cur@IR820-ss-PEG exhibit prolonged blood half-life time, better tumor accumulation and retention, enhanced tumor hypoxia-inducible factor-1α (HIF-1α) and vascular endothelial cell growth factor (VEGF) suppression effect as compared to IR820/Cur. In vivo antitumor activity study, Cur@IR820-ss-PEG effectively inhibit the tumor angiogenesis, which potentiates the PDT efficacy and leads to the best in vivo antitumor effect of Cur@IR820-ss-PEG. This work provides a novel and relatively simple strategy for synergistic cancer chemo-photodynamic therapy.

Phytochemicals as Regulators of Tumor Glycolysis and Hypoxia Signaling Pathways: Evidence from In Vitro Studies

The full understanding of the complex nature of cancer still faces many challenges, as cancers arise not as a result of a single target disruption but rather involving successive genetic and epigenetic alterations leading to multiple altered metabolic pathways. In this light, the need for a multitargeted, safe and effective therapy becomes essential. Substantial experimental evidence upholds the potential of plant-derived compounds to interfere in several important pathways, such as tumor glycolysis and the upstream regulating mechanisms of hypoxia. Herein, we present a comprehensive overview of the natural compounds which demonstrated, in vitro studies, an effective anticancer activity by affecting key regulators of the glycolytic pathway such as glucose transporters, hexokinases, phosphofructokinase, pyruvate kinase or lactate dehydrogenase. Moreover, we assessed how phytochemicals could interfere in HIF-1 synthesis, stabilization, accumulation, and transactivation, emphasizing PI3K/Akt/mTOR and MAPK/ERK pathways as important signaling cascades in HIF-1 activation. Special consideration was given to cell culture-based metabolomics as one of the most sensitive, accurate, and comprising approaches for understanding the response of cancer cell metabolome to phytochemicals.

β-cyclodextrin encapsulation of curcumin elicits an altered mode of angiogenin inhibition: In vitro and in vivo studies

The interaction of curcumin (Cur) with human angiogenin (hAng), a potent blood vessel inducer responsible for angiogenesis is found to change following encapsulation within the β-cyclodextrin (βCD) cavity. The enhanced bioavailability and increase in the binding stoichiometry of hAng:Cur-βCD (1:2) leads to increased affinity, hence an increase in the association constant. The altered mode of hAng inhibition of Cur from a non-competitive (K_I = 23.7 ± 2.2 μM) to a mixed type (K_I = 19.8 ± 1.4 μM), after encapsulation provides an insight into interaction patterns. Isothermal titration calorimetry (ITC) experiments indicate the formation of multiple favorable non-covalent interactions (also confirmed by docking studies), which implies negative enthalpy changes (-ΔH^o) and restriction in the dynamic mobility of the free protein molecule resulting in a very less positive entropy change (TΔS^o). This leads to a medium magnitude for the spontaneous free energy change associated with the interaction/binding process. The spontaneity of binding indicates a more favorable value for the Cur-βCD (ΔG^o = -7.75 kcal/mol) compared to Cur (ΔG^o = -7.49 kcal/mol). In vivo studies also demonstrate the anti-angiogenic effect of Cur/Cur-βCD confirmed by the significant decrease in blood vessel density and branching index.

EGPI-1, a novel eIF4E/eIF4G interaction inhibitor, inhibits lung cancer cell growth and angiogenesis through Ras/MNK/ERK/eIF4E signaling pathway

eIF4E plays an important role in regulating tumor growth and angiogenesis, and eIF4E is highly expressed in a variety of lung cancer cell lines. siRNA eIF4E can significantly inhibit the proliferation of lung cancer cells, indicating that inhibition of eIF4E may become a novel anti-tumor target. In the previous study, we synthesized a series of small molecule compounds with the potential to inhibit eIF4E. Among them, the compound EGPI-1 significantly inhibited the proliferation of a variety of lung cancer cells such as A549, NCI-H460, NCI-H1650 and 95D without inhibiting the proliferation of HUVEC cells. Further studies found that EGPI-1 interfered with the eIF4E/eIF4G interaction and inhibited the phosphorylation of eIF4E in NCI-H460 cells. The results of flow cytometry showed that EGPI-1 induced apoptosis and G0/G1 cycle arrest in NCI-H460 cell. Interestingly, we also found that EGPI-1 induced autophagy and DNA damage in NCI-H460 cells. The mechanism results showed that EGPI-1 inhibited the Ras/MNK/ERK/eIF4E signaling pathway. Moreover, EGPI-1 inhibited tube formation of HUVECs, as well as inhibited the neovascularization of CAM, proving the anti-angiogenesis activity of EGPI-1. The NCI-H460 xenograft studies showed that EGPI-1 inhibited tumor growth and angiogenesis in vivo by regulating Ras/MNK/ERK/eIF4E pathway. Our studies proved that eIF4E was a novel target for regulating tumor growth, and the eIF4E/eIF4G interaction inhibitor EGPI-1 was promising to develop into a novel anti-lung cancer drug.

A Long-Acting Curcumin Nanoparticle/In Situ Hydrogel Composite for the Treatment of Uveal Melanoma

Uveal melanoma (UM) is the most common primary intraocular tumor in adults with high mortality. In order to improve prognosis and survival of UM patients, it is critical to inhibit tumor progression and metastasis as early as possible after the initial presentation/diagnosis of the disease. Sustained local delivery of antitumor therapeutics in the posterior region can potentially achieve long-term UM inhibition, improve target therapeutic delivery to the posterior segments, as well as reduce injection frequency and hence improved patient compliance. To address the highly unmet medical need in UM therapy, a bioinspired in situ gelling hydrogel system composed of naturally occurring biopolymers collagen and hyaluronic acid was developed in the present research. Curcumin with anti-cancer progression, anti-metastasis effects, and good ocular safety was chosen as the model therapeutic. The developed in situ gelling delivery system gelled at 37 °C within two minutes and demonstrated excellent biocompatibility and slow degradation. The curcumin-loaded nanoparticle/hydrogel composite was able to sustain release payload for up to four weeks. The optimized nanoparticle/hydrogel composite showed effective inhibition of human UM cell proliferation. This novel nanoparticle/in situ hydrogel composite demonstrated a great potential for the treatment of the rare and devastating intraocular cancer.

Naturally-derived targeted therapy for wound healing: Beyond classical strategies

This review summarizes the four processes of wound healing in the human body (hemostasis, inflammatory, proliferation, and remodeling) and the most current research on the most important factors affecting cutaneous wound healing and the underlying cellular and/or molecular pathways. Local factors, including temperature, oxygenation, and infection, and systemic factors, such as age, diabetes, sex hormones, genetic components, autoimmune diseases, psychological stress, smoking and obesity are also addressed. A better understanding of the role of these factors in wound repair could result in the development of therapeutics that promote wound healing and resolve affected wounds. Additionally, natural products obtained from plants and animals are critical targets for the discovery of novel biologically significant pharmacophores, such as medicines and agrochemicals. This review outlines the most recent advances in naturally derived targeted treatment for wound healing. These are plant-derived natural products, insect-derived natural products, marine-derived natural products, nanomaterial-based wound-healing therapeutics (metal- and non-metal-based nanoparticles), and natural product-based nanomedicine to improve the future direction of wound healing. Natural products extracted from plants and animals have advanced significantly, particularly in the treatment of wound healing. As a result, the isolation and extraction of bioactive compounds from a variety of sources can continue to advance our understanding of wound healing. Undescribed bioactive compounds or unexplored formulations that could have a role in today's medicinal arsenal may be contained in the abundance of natural products and natural product derivatives.

Dual-Ligand-Modified Liposomes Co-Loaded with Anti-Angiogenic and Chemotherapeutic Drugs for Inhibiting Tumor Angiogenesis and Metastasis

BACKGROUND

Tumor angiogenesis has been proven to potentiate tumor growth and metastasis; therefore, the strategies targeting tumor-related angiogenesis have great potentials in antitumor therapy.

METHODS

Here, the GA&Gal dual-ligand-modified liposomes co-loaded with curcumin and combretastatin A-4 phosphate (CUCA/GA&Gal-Lip) were prepared and characterized. A novel "BEL-7402+HUVEC" co-cultured cell model was established to mimic tumor microenvironment. The cytotoxicity and migration assays were performed against the novel co-cultured model. Angiogenesis ability was evaluated by tube formation test, and in vivo metastatic ability was evaluated by lung metastasis test.

RESULTS

The result demonstrated that dual-ligand-modified liposomes showed greater inhibition of tumor angiogenesis and metastasis in comparison with other combined groups. Significantly, the mechanism analysis revealed that curcumin and combretastatin A-4 phosphate could inhibit tumor angiogenesis and metastasis via down-regulation of VEGF and VEGFR2 expression, respectively, and that GA&Gal-Lip could improve antitumor effect by GA/Gal-mediated active-targeting delivery.

CONCLUSION

CUCA/GA&Gal-Lip hold great potentials in hepatoma-targeting delivery of antitumor drugs and can achieve anti-angiogenic and anti-metastatic effects by simultaneously blocking VEGF/VEGFR2 signal pathway, therefore exhibiting superior anti-hepatoma efficacy.

Nanotechnology for angiogenesis: opportunities and challenges

Angiogenesis plays a critical role within the human body, from the early stages of life (i.e., embryonic development) to life-threatening diseases (e.g., cancer, heart attack, stroke, wound healing). Many pharmaceutical companies have expended huge efforts on both stimulation and inhibition of angiogenesis. During the last decade, the nanotechnology revolution has made a great impact in medicine, and regulatory approvals are starting to be achieved for nanomedicines to treat a wide range of diseases. Angiogenesis therapies involve the inhibition of angiogenesis in oncology and ophthalmology, and stimulation of angiogenesis in wound healing and tissue engineering. This review aims to summarize nanotechnology-based strategies that have been explored in the broad area of angiogenesis. Lipid-based, carbon-based and polymeric nanoparticles, and a wide range of inorganic and metallic nanoparticles are covered in detail. Theranostic and imaging approaches can be facilitated by nanoparticles. Many preparations have been reported to have a bimodal effect where they stimulate angiogenesis at low dose and inhibit it at higher doses.

Evidence for the Capability of Roxadustat (FG-4592), an Oral HIF Prolyl-Hydroxylase Inhibitor, to Perturb Membrane Ionic Currents: An Unidentified yet Important Action

Roxadustat (FG-4592), an analog of 2-oxoglutarate, is an orally-administered, heterocyclic small molecule known to be an inhibitor of hypoxia inducible factor (HIF) prolyl hydroxylase. However, none of the studies have thus far thoroughly investigated its possible perturbations on membrane ion currents in endocrine or heart cells. In our studies, the whole-cell current recordings of the patch-clamp technique showed that the presence of roxadustat effectively and differentially suppressed the peak and late components of I_K(DR) amplitude in response to membrane depolarization in pituitary tumor (GH₃) cells with an IC₅₀ value of 5.71 and 1.32 μM, respectively. The current inactivation of I_K(DR) elicited by 10-sec membrane depolarization became raised in the presence of roxadustatt. When cells were exposed to either CoCl₂ or deferoxamine (DFO), the I_K(DR) elicited by membrane depolarization was not modified; however, nonactin, a K⁺-selective ionophore, in continued presence of roxadustat, attenuated roxadustat-mediated inhibition of the amplitude. The steady-state inactivation of I_K(DR) could be constructed in the presence of roxadustat. Recovery of I_K(DR) block by roxadustat (3 and 10 μM) could be fitted by a single exponential with 382 and 523 msec, respectively. The roxadustat addition slightly suppressed erg-mediated K⁺ or hyperpolarization-activated cation currents. This drug also decreased the peak amplitude of voltage-gated Na⁺ current with a slowing in inactivation rate of the current. Likewise, in H9c2 heart-derived cells, the addition of roxadustat suppressed I_K(DR) amplitude in combination with the shortening in inactivation time course of the current. In high glucose-treated H9c2 cells, roxadustat-mediated inhibition of I_K(DR) remained unchanged. Collectively, despite its suppression of HIF prolyl hydroxylase, inhibitory actions of roxadustat on different types of ionic currents possibly in a non-genomic fashion might provide another yet unidentified mechanism through which cellular functions are seriously perturbed, if similar findings occur in vivo.

Curcumin in tissue engineering: A traditional remedy for modern medicine

Curcumin is the principal polyphenolic compound present in turmeric with broad applications in tissue engineering and regenerative medicine. It has some important inherent properties with the potential to facilitate tissue healing, including anti-inflammatory, anti-oxidant, and antibacterial activities. Therefore, curcumin has been used for the treatment of various damaged tissues, especially wound injuries. There are different forms of curcumin, among which nano-formulations are of a great importance in regenerative medicine. It is also important to design sophisticated delivery systems for controlled/localized delivery of curcumin to the target tissues and organs. Although there are many reports on the advantages of this compound, further research is required to fully explore its clinical usage. The review describes the physicochemical and biological properties of curcumin and the current state of the evidence on its applications in tissue engineering. © 2018 BioFactors, 45(2):135-151, 2019.

Molecular Network Basis of Invasive Pituitary Adenoma: A Review

Cases with pituitary adenoma comprise 10-25% of intracranial neoplasm, being the third most common intracranial tumor, most of the adenomas are considered to be benign. About 35% of pituitary adenomas are invasive. This review summarized the known molecular basis of the invasiveness of pituitary adenomas. The study pointed out that hypoxia-inducible factor-1α, pituitary tumor transforming gene, vascular endothelial growth factor, fibroblast growth factor-2, and matrix metalloproteinases (MMPs, mainly MMP-2, and MMP-9) are core molecules responsible for the invasiveness of pituitary adenomas. The reason is that these molecules have the ability to directly or indirectly induce cell proliferation, epithelial-to-mesenchymal transition, angiogenesis, degradation, and remodeling of extracellular matrix. HIF-1α induced by hypoxia or apoplexy inside the adenoma might be the initiating factor of invasive transformation, followed with angiogenesis for overexpressed VEGF, EMT for overexpressed PTTG, degradation of ECM for overexpressed MMPs, creating a suitable microenvironment within the tumor. Together, they form a complex interactive network. More investigations are required to further elucidate the mechanisms underlying the invasiveness of pituitary adenomas.

Macrophage plasticity, polarization and function in response to curcumin, a diet-derived polyphenol, as an immunomodulatory agent

Monocytes and macrophages are important cells of the innate immune system that have diverse functions, including defense against invading pathogens, removal of dead cells by phagocytosis, antigen presentation in the context of MHC class I and class II molecules, and production of various pro-inflammatory cytokines and chemokines such as IL-1β, IL-6, TNF-α and MCP-1. In addition, pro-inflammatory (M1) and anti-inflammatory (M2) macrophages clearly play important roles in the progression of several inflammatory diseases. Therefore, therapies that target macrophage polarization and function by either blocking their trafficking to sites of inflammation, or skewing M1 to M2 phenotype polarization may hold clinical promise in several inflammatory diseases. Dietary-derived polyphenols have potent natural anti-oxidative properties. Within this group of polyphenols, curcumin has been shown to suppress macrophage inflammatory responses. Curcumin significantly reduces co-stimulatory molecules and also inhibits MAPK activation and the translocation of NF-κB p65. Curcumin can also polarize/repolarize macrophages toward the M2 phenotype. Curcumin-treated macrophages have been shown to be highly efficient at antigen capture and endocytosis via the mannose receptor. These novel findings provide new perspectives for the understanding of the immunopharmacological role of curcumin, as well as its therapeutic potential for impacting macrophage polarization and function in the context of inflammation-related disease. However, the precise effects of curcumin on the migration, differentiation, polarization and immunostimulatory functions of macrophages remain unknown. Therefore, in this review, we summarized whether curcumin can influence macrophage polarization, surface molecule expression, cytokine and chemokine production and their underlying pathways in the prevention of inflammatory diseases.

Effects of curcumin on hypoxia-inducible factor as a new therapeutic target

Hypoxia-inducible factor-1 (HIF-1) is a transcription factor that consists of two subunits, the HIF-1α and HIF-1β (ARNT). Under hypoxic conditions, HIF-1 is an adaptive system that regulates the transcription of multiple genes associated with growth, angiogenesis, proliferation, glucose transport, metabolism, pH regulation and cell death. However, aberrant HIF-1 activation contributes to the pathophysiology of several human diseases such as cancer, ischemic cardiovascular disorders, and pulmonary and kidney diseases. A growing body of evidence indicates that curcumin, a natural bioactive compound of turmeric root, significantly targets both HIF-1 subunits, but is more potent against HIF-1α. In this review, we have summarized the knowledge about the pharmacological effects of curcumin on HIF-1 and the related molecular mechanisms that may be effective candidates for the development of multi-targeted therapy for several human diseases.

SWATH-MS based quantitative proteomics analysis reveals that curcumin alters the metabolic enzyme profile of CML cells by affecting the activity of miR-22/IPO7/HIF-1α axis

BACKGROUND

Chronic myelogenous leukemia (CML) is a myeloproliferative disorder caused by expression of the chimeric BCR-ABL tyrosine kinase oncogene, resulting from the t(9;22) chromosomal translocation. Imatinib (gleevec, STI-571) is a selective inhibitor of BCR-ABL activity highly effective in the treatment of CML. However, even though almost all CML patients respond to treatment with imatinib or third generation inhibitors, these drugs are not curative and need to be taken indefinitely or until patients become resistant. Therefore, to get a definitive eradication of leukemic cells, it is necessary to find novel therapeutic combinations, for achieving greater efficacy and fewer side effects. Curcumin is an Indian spice with several therapeutic properties: anti-oxidant, analgesic, anti-inflammatory, antiseptic and anti-cancer. In cancer disease, it acts by blocking cell transformation, proliferation, and invasion and by inducing cell apoptosis.

METHODS

In the present study, the effect of a sub-toxic dose of curcumin on K562 cells was evaluated by using the technique of Sequential Window Activation of All Theoretical Mass Spectra (SWATH-MS). Bioinformatic analysis of proteomic data was performed to highlight the pathways mostly affected by the treatment. The involvement of Hypoxia inducible factor 1 α (HIF-1α) was assayed by evaluating its activation status and the modulation of importin 7 (IPO7) and miR-22 was assessed by quantitative PCR and western blot analysis. Finally, K562 cells transfected with miR-22 inhibitor were used to confirm the ability of curcumin to elicit miR-22 expression.

RESULTS

Our findings revealed that the most relevant effect induced by curcumin was a consistent decrease of several proteins involved in glucose metabolism, most of which were HIF-1α targets, concomitant with the up-regulation of functional and structural mitochondrial proteins. The mechanism by which curcumin affects metabolic enzyme profile was associated with the reduction of HIF-1α activity, due to the miR-22-mediated down-regulation of IPO7 expression. Finally, the ability of curcumin to enhance in vitro the efficiency of imatinib was reported.

CONCLUSIONS

In summary, our data indicates that the miR-22/IPO7/HIF-1α axis may be considered as a novel molecular target of curcumin adding new insights to better define therapeutic activity and anticancer properties of this natural compound. The MS proteomic data have been deposited to the ProteomeXchange with identifier <PXD007771>.

Topical Curcumin Nanocarriers are Neuroprotective in Eye Disease

Curcumin (1,7-bis-(4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5dione) is a polyphenol extracted from turmeric that has long been advocated for the treatment of a variety of conditions including neurodegenerative and inflammatory disorders. Despite this promise, the clinical use of curcumin has been limited by the poor solubility and low bioavailability of this molecule. In this article, we describe a novel nanocarrier formulation comprising Pluronic-F127 stabilised D-α-Tocopherol polyethene glycol 1000 succinate nanoparticles, which were used to successfully solubilize high concentrations (4.3 mg/mL) of curcumin. Characterisation with x-ray diffraction and in vitro release assays localise curcumin to the nanocarrier interior, with each particle measuring <20 nm diameter. Curcumin-loaded nanocarriers (CN) were found to significantly protect against cobalt chloride induced hypoxia and glutamate induced toxicity in vitro, with CN treatment significantly increasing R28 cell viability. Using established glaucoma-related in vivo models of ocular hypertension (OHT) and partial optic nerve transection (pONT), topical application of CN twice-daily for three weeks significantly reduced retinal ganglion cell loss compared to controls. Collectively, these results suggest that our novel topical CN formulation has potential as an effective neuroprotective therapy in glaucoma and other eye diseases with neuronal pathology.

Targeting VEGF/VEGFRs Pathway in the Antiangiogenic Treatment of Human Cancers by Traditional Chinese Medicine

Bearing in mind the doctrine of tumor angiogenesis hypothesized by Folkman several decades ago, the fundamental strategy for alleviating numerous cancer indications may be the strengthening application of notable antiangiogenic therapies to inhibit metastasis-related tumor growth. Under physiological conditions, vascular sprouting is a relatively infrequent event unless when specifically stimulated by pathogenic factors that contribute to the accumulation of angiogenic activators such as the vascular endothelial growth factor (VEGF) family and basic fibroblast growth factor (bFGF). Since VEGFs have been identified as the principal cytokine to initiate angiogenesis in tumor growth, synthetic VEGF-targeting medicines containing bevacizumab and sorafenib have been extensively used, but prominent side effects have concomitantly emerged. Traditional Chinese medicines (TCM)–derived agents with distinctive safety profiles have shown their multitarget curative potential by impairing angiogenic stimulatory signaling pathways directly or eliciting synergistically therapeutic effects with anti-angiogenic drugs mainly targeting VEGF-dependent pathways. This review aims to summarize (a) the up-to-date understanding of the role of VEGF/VEGFR in correlation with proangiogenic mechanisms in various tissues and cells; (b) the elaboration of antitumor angiogenesis mechanisms of 4 representative TCMs, including Salvia miltiorrhiza, Curcuma longa, ginsenosides, and Scutellaria baicalensis; and (c) circumstantial clarification of TCM-driven therapeutic actions of suppressing tumor angiogenesis by targeting VEGF/VEGFRs pathway in recent years, based on network pharmacology.

Curcumin induces apoptosis and inhibits proliferation in infantile hemangioma endothelial cells via downregulation of MCL-1 and HIF-1α

BACKGROUND

Curcumin has been used as an alternative medicine for the treatment of infantile hemangiomas (IHs); however, the mechanism underlying the effectiveness of curcumin in IHs remains largely unclear.

METHODS

In this study, we isolated primary human hemangioma endothelial cells (HemECs) from fresh surgical specimens of 3 patients. We treated HemECs by curcumin and investigated the alterations in proliferative and apoptotic signaling pathways with cell counting kit-8, flow cytometry, western blotting, immunofluorescence, and real-time polymerase chain reaction.

RESULTS AND CONCLUSION

We found that curcumin potently inhibited proliferation in HemECs, achieving low-micromolar IC50 (the half maximal inhibitory concentration) value. We also observed that treatment with curcumin induced apoptosis in HemECs, as evidenced by positively Annexin-V-FITC staining, caspase-3 activation, and cleavage of poly(adenosine diphosphate-ribose) polymerase (PARP) in the treated cells. Moreover, we showed that curcumin suppressed the expression of antiapoptotic protein myeloid cell leukemia-1 (MCL-1), hypoxia-inducible factor 1α (HIF-1α), and vascular endothelial growth factor (VEGF).Altogether, our study suggests that the effectiveness of curcumin in IHs may be associated with its potent antiproliferative and apoptotic activities in HemECs.

Curcumin induces therapeutic angiogenesis in a diabetic mouse hindlimb ischemia model via modulating the function of endothelial progenitor cells

Background

Neovascularization is impaired in diabetes mellitus, which leads to the development of peripheral arterial disease and is mainly attributed to the dysfunction of endothelial progenitor cells (EPCs). Previous studies proved the promotional effect of curcumin on neovascularization in wound healing of diabetes. Thus, we hypothesize that curcumin could promote neovascularization at sites of hindlimb ischemia in diabetes and might take effect via modulating the function of EPCs.

Methods

Streptozotocin-induced type 1 diabetic mice and nondiabetic mice both received unilateral hindlimb ischemic surgery. Curcumin was then administrated to the mice by lavage for 14 days consecutively. Laser Doppler perfusion imaging was conducted to demonstrate the blood flow reperfusion. Capillary density was measured in the ischemic gastrocnemius muscle. In addition, angiogenesis, migration, proliferation abilities, and senescence were determined in EPCs isolated from diabetic and nondiabetic mice. Quantitative PCR was then used to determine the mRNA expression of vascular endothelial growth factor (VEGF) and angiopoetin-1 (Ang-1) in EPCs.

Results

Curcumin application to type 1 diabetic mice significantly improved blood reperfusion and increased the capillary density in ischemic hindlimbs. The in-vitro study also revealed that the angiogenesis, migration, and proliferation abilities of EPCs and the number of senescent EPCs were reversed by curcumin application. Quantitative PCR confirmed the overexpression of VEGF-A and Ang-1 in EPCs after curcumin treatment.

Conclusion

Curcumin could enhance neovascularization via promoting the function of EPCs in a diabetic mouse hindlimb ischemia model.

Electronic supplementary material

The online version of this article (doi:10.1186/s13287-017-0636-9) contains supplementary material, which is available to authorized users.

Curcumin mediates anticancer effects by modulating multiple cell signaling pathways

Curcumin, a component of a spice native to India, was first isolated in 1815 by Vogel and Pelletier from the rhizomes of Curcuma longa (turmeric) and, subsequently, the chemical structure of curcumin as diferuloylmethane was reported by Milobedzka et al. [(1910) 43., 2163-2170]. Since then, this polyphenol has been shown to exhibit antioxidant, anti-inflammatory, anticancer, antiviral, antibacterial, and antifungal activities. The current review primarily focuses on the anticancer potential of curcumin through the modulation of multiple cell signaling pathways. Curcumin modulates diverse transcription factors, inflammatory cytokines, enzymes, kinases, growth factors, receptors, and various other proteins with an affinity ranging from the pM to the mM range. Furthermore, curcumin effectively regulates tumor cell growth via modulation of numerous cell signaling pathways and potentiates the effect of chemotherapeutic agents and radiation against cancer. Curcumin can interact with most of the targets that are modulated by FDA-approved drugs for cancer therapy. The focus of this review is to discuss the molecular basis for the anticancer activities of curcumin based on preclinical and clinical findings.

Angiomodulators in cancer therapy: New perspectives

The formation of new blood vessels plays a crucial for the development and progression of pathophysiological changes associated with a variety of disorders, including carcinogenesis. Angiogenesis inhibitors (anti-angiogenics) are an important part of treatment for some types of cancer. Some natural products isolated from marine invertebrates have revealed antiangiogenic activities, which are diverse in structure and mechanisms of action. Many preclinical studies have generated new models for further modification and optimization of anti-angiogenic substances, and new information for mechanistic studies and new anti-cancer drug candidates for clinical practice. Moreover, in the last decade it has become apparent that galectins are important regulators of tumor angiogenesis, as well as microRNA. MicroRNAs have been validated to modulate endothelial cell migration or endothelial tube organization. In the present review we summarize the current knowledge regarding the role of marine-derived natural products, galectins and microRNAs in tumor angiogenesis.

Isorhamnetin Inhibits Reactive Oxygen Species-Dependent Hypoxia Inducible Factor (HIF)-1α Accumulation

Isorhamnetin is a flavonoid metabolite of quercetin and isolated from water dropwort (Oenanthe javanica, Umbelliferae). It has been reported that isorhamnetin exerts beneficial effects including antioxidant, anti-inflammatory, and anti-proliferative activities. The present study investigated whether the antioxidant activity of isorhamnetin is correlated with its anti-cancer effects on colorectal cancer cells. Isorhamnetin significantly repressed cobalt chloride (CoCl₂)- or hypoxia-induced hypoxia inducible factor-1α (HIF-1α) accumulation in HCT116 and HT29 cells. When compared with quercetin, isorhamnetin showed potent inhibition of HIF-1α. Moreover, it inhibited CoCl₂-induced activity of hypoxia response element reporter gene and HIF-1α-dependent transcription of genes such as glucose transporter 1, lactate dehydrogenase A, carbonic anhydrase-IX, and pyruvate dehydrogenase kinase 1. Isorhamnetin also blocked hydrogen peroxide (H₂O₂)-induced HIF-1α accumulation. The antioxidant effects of isorhamnetin were confirmed by observation of CoCl₂- or H₂O₂-induced reactive oxygen species (ROS) production. Consistently, overexpressed HIF-1α was decreased by isorhamnetin or N-acetyl-L-cysteine in HEK293 cells. In vitro migration and invasion assay further confirmed the inhibitory effects of isorhamnetin on cancer cells. Collectively, these results demonstrate that isorhamnetin inhibits ROS-mediated HIF-1α accumulation, which contributes to its anti-metastatic efficacy.

Unraveling the Anticancer Effect of Curcumin and Resveratrol

Resveratrol and curcumin are natural products with important therapeutic properties useful to treat several human diseases, including cancer. In the last years, the number of studies describing the effect of both polyphenols against cancer has increased; however, the mechanism of action in all of those cases is not completely comprehended. The unspecific effect and the ability to interfere in assays by both polyphenols make this challenge even more difficult. Herein, we analyzed the anticancer activity of resveratrol and curcumin reported in the literature in the last 11 years, in order to unravel the molecular mechanism of action of both compounds. Molecular targets and cellular pathways will be described. Furthermore, we also discussed the ability of these natural products act as chemopreventive and its use in association with other anticancer drugs.

Therapeutic Potential of Curcumin for the Treatment of Brain Tumors

Brain malignancies currently carry a poor prognosis despite the current multimodal standard of care that includes surgical resection and adjuvant chemotherapy and radiation. As new therapies are desperately needed, naturally occurring chemical compounds have been studied for their potential chemotherapeutic benefits and low toxicity profile. Curcumin, found in the rhizome of turmeric, has extensive therapeutic promise via its antioxidant, anti-inflammatory, and antiproliferative properties. Preclinical in vitro and in vivo data have shown it to be an effective treatment for brain tumors including glioblastoma multiforme. These effects are potentiated by curcumin's ability to induce G2/M cell cycle arrest, activation of apoptotic pathways, induction of autophagy, disruption of molecular signaling, inhibition of invasion, and metastasis and by increasing the efficacy of existing chemotherapeutics. Further, clinical data suggest that it has low toxicity in humans even at large doses. Curcumin is a promising nutraceutical compound that should be evaluated in clinical trials for the treatment of human brain tumors.

Curcumin inhibits angiogenesis and improves defective hematopoiesis induced by tumor-derived VEGF in tumor model through modulating VEGF-VEGFR2 signaling pathway

Curcumin, a natural polyphenol compound from the perennial herb Curcuma longa, has been proved to be beneficial for tumor-bearing animals through inhibiting tumor neovasculature formation, but the underlying mechanisms are unclear. Here, we aim to test whether curcumin affects VEGF-VEGFR2 signaling pathway and attenuates defective hematopoiesis induced by VEGF in tumor model. We demonstrated that curcumin inhibited proliferation, migration of HUVEC under VEGF stimulation and caused HUVEC apoptosis, and blocked VEGFR2 activation and its downstream signaling pathways in vitro. Furthermore, in VEGF over-expressing tumor model, curcumin significantly inhibited the tumor growth accelerated by VEGF in a dose-dependent manner and improved anemia and extramedullary hematopoiesis in livers and spleens of tumor-bearing mice induced by tumor-derived VEGF. Immunohistochemical analysis showed that curcumin normalized vasculature structures of livers and reduced tumor microvessel density. ELISA revealed that curcumin suppressed VEGF secretion from tumor cells both in vitro and in vivo. Survival analysis showed that curcumin significantly improved survival ability of VEGF tumor-bearing mice. Taken together, these findings establish curcumin as a modulator of VEGF and VEGF-VEGFR2 signaling pathway, with potential implication for improving the quality of life of cancer patients.

Hedgehog signaling activation induces stem cell proliferation and hormone release in the adult pituitary gland

Hedgehog (HH) signaling is known to be essential during the embryonal development of the pituitary gland but the knowledge about its role in the adult pituitary and in associated tumors is sparse. In this report we investigated the effect of excess Hh signaling activation in murine pituitary explants and analyzed the HH signaling status of human adenopituitary lobes and a large cohort of pituitary adenomas. Our data show that excess Hh signaling led to increased proliferation of Sox2(+) and Sox9(+) adult pituitary stem cells and to elevated expression levels of adrenocorticotropic hormone (Acth), growth hormone (Gh) and prolactin (Prl) in the adult gland. Inhibition of the pathway by cyclopamine reversed these effects indicating that active Hh signaling positively regulates proliferative processes of adult pituitary stem cells and hormone production in the anterior pituitary. Since hormone producing cells of the adenohypophysis as well as ACTH-, GH- and PRL-immunopositive adenomas express SHH and its target GLI1, we furthermore propose that excess HH signaling is involved in the development/maintenance of hormone-producing pituitary adenomas. These findings advance the understanding of physiological hormone regulation and may open new treatment options for pituitary tumors.

Sustained proliferation in cancer: Mechanisms and novel therapeutic targets

Proliferation is an important part of cancer development and progression. This is manifest by altered expression and/or activity of cell cycle related proteins. Constitutive activation of many signal transduction pathways also stimulates cell growth. Early steps in tumor development are associated with a fibrogenic response and the development of a hypoxic environment which favors the survival and proliferation of cancer stem cells. Part of the survival strategy of cancer stem cells may manifested by alterations in cell metabolism. Once tumors appear, growth and metastasis may be supported by overproduction of appropriate hormones (in hormonally dependent cancers), by promoting angiogenesis, by undergoing epithelial to mesenchymal transition, by triggering autophagy, and by taking cues from surrounding stromal cells. A number of natural compounds (e.g., curcumin, resveratrol, indole-3-carbinol, brassinin, sulforaphane, epigallocatechin-3-gallate, genistein, ellagitannins, lycopene and quercetin) have been found to inhibit one or more pathways that contribute to proliferation (e.g., hypoxia inducible factor 1, nuclear factor kappa B, phosphoinositide 3 kinase/Akt, insulin-like growth factor receptor 1, Wnt, cell cycle associated proteins, as well as androgen and estrogen receptor signaling). These data, in combination with bioinformatics analyses, will be very important for identifying signaling pathways and molecular targets that may provide early diagnostic markers and/or critical targets for the development of new drugs or drug combinations that block tumor formation and progression.

Inhibitory effect of curcumin on testosterone induced benign prostatic hyperplasia rat model

Background

Benign prostatic hyperplasia (BPH) is one of the common male diseases, which is provoked by dihydrotestosterone (DHT) and androgen signals. Several studies showed that curcumin has various effects of prevention and treatment to diseases. We investigated whether curcumin may repress the development of BPH in male Wistar rats.

Methods

Seven weeks male Wistar rats were and divided into 4 groups (normal group, BPH group, finasteride group, curcumin group; n = 8 for each group). In order to induce BPH in rats, rats were castrated and testosterone was injected subcutaneously everyday (s.c., 20 mg/kg). Rats in the curcumin group were treated 50 mg/kg, administered orally for 4 weeks. After 4 weeks, all rats were sacrificed and their prostate and serum were analyzed.

Results

Compared to the finasteride group as positive group, the curcumin group showed similarly protective effect on BPH in histopathologic morphology, prostate volume. Results of immunohistochemistry and western-blot showed decreased expressions of VEGF, TGF-ß1, and IGF1 were also decreased in the curcumin group.

Conclusions

These results suggested that curcumin inhibited the development of BPH and might a useful herbal treatment or functional food for BPH.

Liposomal curcumin inhibits hypoxia-induced angiogenesis after transcatheter arterial embolization in VX2 rabbit liver tumors

Purpose

The purpose of the study is to investigate the inhibition of hypoxia-induced angiogenesis after embolization in VX2 rabbit liver tumors by liposomal curcumin.

Materials and methods

A total of 54 VX2 rabbits were divided into three groups, and each group had three subgroups according to the sacrifice time. The animals in the control group (n=18) underwent sham embolization. Transcatheter arterial embolization (TAE)-treated group (n=18) animals underwent embolization with lipiodol (0.1 mL/kg body weight) and 90–180 µm polyvinyl alcohol (PVA) particles. Liposomal curcumin TAE-treated group (n=18) animals underwent embolization with liposomal curcumin (20 mg/kg body weight) mixed with lipiodol (0.1 mL/kg body weight) and 90–180 µm PVA particles. After embolization, the animals in each subgroup were sacrificed at 6 hours, 24 hours, and 3 days, and the tumor samples were collected. Immunohistochemical staining was performed to evaluate expression of hypoxia-inducible factor-1α (HIF-1α) and vascular endothelial growth factor (VEGF) proteins, and microvessel density (MVD). Real-time polymerase chain reaction was performed to examine VEGF mRNA levels.

Results

The levels of HIF-1α and VEGF, and MVD in tumors of liposomal curcumin TAE-treated group were significantly decreased compared to the TAE-treated group (P<0.05). There was a slight decrease in tumor size in the liposomal curcumin TAE-treated group at third-day time points compared to the TAE-treated group; the difference was not statistically significant (P>0.05). The HIF-1α protein correlated considerably with VEGF mRNA (r=0.705, P=0.001) and protein (r=0.655, P=0.003), and MVD (r=0.521, P=0.027). A significant correlation between VEGF protein and MVD was noted as well (r=0.519, P=0.027).

Conclusion

Liposomal curcumin downregulates HIF-1α protein levels and inhibits hypoxia-induced angiogenesis after embolization in VX2 rabbit liver tumors.

Lack of Oestrogenic Inhibition of the Nuclear Factor-κB Pathway in Somatolactotroph Tumour Cells

Activation of nuclear factor (NF)-κB promotes cell proliferation and inhibits apoptosis. We have previously shown that oestrogens sensitise normal anterior pituitary cells to the apoptotic effect of tumour necrosis factor (TNF)-α by inhibiting NF-κB nuclear translocation. In the present study, we examined whether oestrogens also modulate the NF-κB signalling pathway and apoptosis in GH3 cells, a rat somatolactotroph tumour cell line. As determined by Western blotting, 17β-oestradiol (E2 ) (10(-9) m) increased the nuclear concentration of NF-κB/p105, p65 and p50 in GH3 cells. However, E2 did not modify the expression of Bcl-xL, a NF-κB target gene. TNF-α induced apoptosis of GH3 cells incubated in either the presence or absence of E2 . Inhibition of the NF-kB pathway using BAY 11-7082 (BAY) (5 μm) decreased the viability of GH3 cells and increased the percentage of terminal deoxynucleotidyl transferase dUTP nick end labelling (TUNEL)-positive GH3 cells. BAY also increased TNF-α-induced apoptosis of GH3 cells, an effect that was further increased by an inhibitor of the c-Jun N-terminal protein kinase pathway, SP600125 (10 μm). We also analysed the role of the NF-κB signalling pathway on proliferation and apoptosis of GH3 tumours in vivo. The administration of BAY to nude mice bearing GH3 tumours increased the number of TUNEL-positive cells and decreased the number of proliferating GH3 cells. These findings suggest that GH3 cells lose their oestrogenic inhibitory action on the NF-κB pathway and that the pro-apoptotic effect of TNF-α on these tumour pituitary cells does not require sensitisation by oestrogens as occurs in normal pituitary cells. NF-κB was required for the survival of GH3 cells, suggesting that pharmacological inhibition of the NF-κB pathway could interfere with pituitary tumour progression.

Lactotrophs: the new and major source for VEGF secretion and the influence of ECM on rat pituitary function in vitro

Vascular endothelial growth factor (VEGF) plays a pivotal role in pituitary endocrine function by influencing fenestration and blood vessel growth. Folliculostellate (FS) cells, which represent only a small number of pituitary cells, are recognized to produce VEGF. Tissue sections and primary pituitary cell cultures from rat pituitary glands were performed to co-localize VEGF and pituitary lactotrophs, which represents nearly 50% of all pituitary cells, by immunofluorescence. VEGF is co-localized with prolactin-producing cells in vivo and in vitro. FS cells are present infrequently in vivo (1.6%) and in vitro (2.4%). Culture supernatants were analyzed for the presence of VEGF by ELISA. VEGF levels are always significantly lower in supernatants from the cells that are seeded on Matrigel extracellular matrix (ECM) compared to the cells grown on plastic. Lower VEGF concentrations in supernatants from the pituitary cells cultured on ECM may reflect a more adequate cell environment compared to culture on plastic. These results demonstrate for the first time, that VEGF is expressed by lactotrophs, which outnumber FS cells. These results are of potential clinical relevance especially in oncology for the interpretation of studies investigating anti-angiogenic treatment of pituitary tumors.

Gremlin, a bone morphogenetic protein antagonist, is a crucial angiogenic factor in pituitary adenoma

Gremlin is an antagonist of bone morphogenetic protein (BMP) and a major driving force in skeletal modeling in the fetal stage. Several recent reports have shown that Gremlin is also involved in angiogenesis of lung cancer and diabetic retinopathy. The purpose of this study was to investigate the role of Gremlin in tumor angiogenesis in pituitary adenoma. Double fluorescence immunohistochemistry of Gremlin and CD34 was performed in pituitary adenoma tissues obtained during transsphenoidal surgery in 45 cases (7 PRLoma, 17 GHoma, 2 ACTHoma, and 2 TSHoma). Gremlin and microvascular density (MVD) were detected by double-immunofluorescence microscopy in CD34-positive vessels from tissue microarray analysis of 60 cases of pituitary adenomas (6 PRLoma, 23 GHoma, 22 NFoma, 5 ACTHoma, and 4 TSHoma). In tissue microarray analysis, MVD was significantly correlated with an increased Gremlin level (linear regression: P < 0.005,  r (2) = 0.4958). In contrast, Gremlin expression showed no correlation with tumor subtype or Knosp score. The high level of expression of Gremlin in pituitary adenoma tissue with many CD34-positive vessels and the strong coherence of these regions indicate that Gremlin is associated with angiogenesis in pituitary adenoma cells.

Curcumin-induced angiogenesis hastens wound healing in diabetic rats

BACKGROUND

Neovasculogenesis, vital for wound healing, gets compromised in diabetics patients, which consequently delayed wound healing. Previous studies have shown curcumin as both a stimulatory and an inhibitory agent in the neovasculogenesis process. So, present study was aimed to investigate the effects of curcumin on wound healing in diabetic rats and to explore the expressions of the various factors involved in neovasculogenesis.

MATERIALS AND METHODS

Open excisional diabetic wound was created in sixty rats and divided into three groups viz. i) control, ii) pluronic gel-treated, and iii) curcumin-treated. The pluronic F-127 gel (25%) and curcumin (0.3%) in the pluronic gel were topically applied once daily for 19 d. The wound healing and neovasculogenesis among these groups were evaluated by gross appearance of wounds and microscopically by hematoxylin and eosin staining, immunohistochemistry for CD31, messenger RNA expressions of vascular endothelial growth factor (VEGF), transforming growth factor (TGF)-β1, hypoxia-inducible growth factor-1 alpha, stromal cell-derived growth factor-1 alpha, and heme oxygenase-1, and Western blotting studies of VEGF and TGF-β1 in granulation and/or healing tissue on days 3, 7, 14, and 19.

RESULTS

Curcumin application caused markedly fast wound closure with well-formed granulation tissue dominated by fibroblast proliferation, collagen deposition, and complete early regenerated epithelial layer. Immunohistochemistry for CD31 revealed well-formed blood vessels with increased microvessel density on days 3, 7, and 14 in the curcumin-treated group. Expressions of VEGF and TGF-β1 on days 3, 7, and 14, hypoxia-inducible growth factor-1 alpha, stromal cell-derived growth factor-1 alpha, and heme oxygenase-1 on days 3 and 7 were increased in curcumin-treated diabetic rats, as compared with other groups.

CONCLUSIONS

Curcumin enhanced the neovasculogenesis and accelerated the wound healing in diabetic rats by increased expressions of various factors.

Angiogenesis in pituitary adenomas: human studies and new mutant mouse models

The role of angiogenesis in pituitary tumor development has been questioned, as pituitary tumors have been usually found to be less vascularized than the normal pituitary tissue. Nevertheless, a significantly higher degree of vasculature has been shown in invasive or macropituitary prolactinomas when compared to noninvasive and microprolactinomas. Many growth factors and their receptors are involved in pituitary tumor development. For example, VEGF, FGF-2, FGFR1, and PTTG, which give a particular vascular phenotype, are modified in human and experimental pituitary adenomas of different histotypes. In particular, vascular endothelial growth factor, VEGF, the central mediator of angiogenesis in endocrine glands, was encountered in experimental and human pituitary tumors at different levels of expression and, in particular, was higher in dopamine agonist resistant prolactinomas. Furthermore, several anti-VEGF techniques lowered tumor burden in human and experimental pituitary adenomas. Therefore, even though the role of angiogenesis in pituitary adenomas is contentious, VEGF, making permeable pituitary endothelia, might contribute to adequate temporal vascular supply and mechanisms other than endothelial cell proliferation. The study of angiogenic factor expression in aggressive prolactinomas with resistance to dopamine agonists will yield important data in the search of therapeutical alternatives.

Molecular mechanisms of curcumin action: gene expression

Curcumin derived from the tropical plant Curcuma longa has a long history of use as a dietary agent, food preservative, and in traditional Asian medicine. It has been used for centuries to treat biliary disorders, anorexia, cough, diabetic wounds, hepatic disorders, rheumatism, and sinusitis. The preventive and therapeutic properties of curcumin are associated with its antioxidant, anti-inflammatory, and anticancer properties. Extensive research over several decades has attempted to identify the molecular mechanisms of curcumin action. Curcumin modulates numerous molecular targets by altering their gene expression, signaling pathways, or through direct interaction. Curcumin regulates the expression of inflammatory cytokines (e.g., TNF, IL-1), growth factors (e.g., VEGF, EGF, FGF), growth factor receptors (e.g., EGFR, HER-2, AR), enzymes (e.g., COX-2, LOX, MMP9, MAPK, mTOR, Akt), adhesion molecules (e.g., ELAM-1, ICAM-1, VCAM-1), apoptosis related proteins (e.g., Bcl-2, caspases, DR, Fas), and cell cycle proteins (e.g., cyclin D1). Curcumin modulates the activity of several transcription factors (e.g., NF-κB, AP-1, STAT) and their signaling pathways. Based on its ability to affect multiple targets, curcumin has the potential for the prevention and treatment of various diseases including cancers, arthritis, allergies, atherosclerosis, aging, neurodegenerative disease, hepatic disorders, obesity, diabetes, psoriasis, and autoimmune diseases. This review summarizes the molecular mechanisms of modulation of gene expression by curcumin.