Multi-targeted therapy by curcumin: how spicy is it?

The combined effect of encapsulating curcumin and C6 ceramide in liposomal nanoparticles against osteosarcoma

This study examines the antitumor potential of curcumin and C6 ceramide (C6) against osteosarcoma (OS) cell lines when both are encapsulated in the bilayer of liposomal nanoparticles. Three liposomal formulations were prepared: curcumin liposomes, C6 liposomes and C6-curcumin liposomes. Curcumin in combination with C6 showed 1.5 times enhanced cytotoxic effect in the case of MG-63 and KHOS OS cell lines, in comparison with curcumin liposomes alone. Importantly, C6-curcumin liposomes were found to be less toxic on untransformed primary human cells (human mesenchymal stem cells) in comparison to OS cell lines. In addition, cell cycle assays on a KHOS cell line after treatment revealed that curcumin only liposomes induced G2/M arrest by upregulation of cyclin B1, while C6 only liposomes induced G1 arrest by downregulation of cyclin D1. C6-curcumin liposomes induced G2/M arrest and showed a combined effect in the expression levels of cyclin D1 and cyclin B1. The efficiency of the preparations was tested in vivo using a human osteosarcoma xenograft assay. Using pegylated liposomes to increase the plasma half-life and tagging with folate (FA) for targeted delivery in vivo, a significant reduction in tumor size was observed with C6-curcumin-FA liposomes. The encapsulation of two water insoluble drugs, curcumin and C6, in the lipid bilayer of liposomes enhances the cytotoxic effect and validates the potential of combined drug therapy.

Protection from UVB Toxicity in Human Keratinocytes by Thailand Native Herbs Extracts

Thai traditional medicine employs a wide range of indigenous herbs in the forms of tincture or tea for the cure of skin and systemic inflammatory diseases. The protection by Thai plants extracts against UVB DNA damage and cytotoxicity was investigated in human keratinocytes. Petroleum ether, dichloromethane and ethanol extracts were prepared from 15 Thai herb species, and the total phenolic and flavonoid contents, the antioxidant and UV-absorbing properties were assessed by standard procedures. Cytoprotective effects were evaluated on the basis of cell survival, caspase-3 activity and pyrimidine dimers determination. High total phenolic and flavonoid contents were found in the ethanol and dichloromethane fractions. Dichloromethane extract of turmeric was shown to possess the highest antioxidant activity. The maximum UV absorptions were found in the ethanol extract of turmeric and in the dichloromethane extract of ginger. These extracts stimulated the synthesis of Thioredoxin 1, an antioxidant protein, and could protect human HaCaT keratinocytes from UV-induced DNA damage and cytotoxicity. The present data support the utilization of turmeric and ginger extracts in anti-UV cosmetic pharmaceuticals.

Molecular mechanisms behind anti-cancer effects of curcumin in hepatocellular carcinoma

Primary liver cancer, also known as hepatocellular carcinoma (HCC), is one of the most lethal cancers worldwide. Most HCC cases are reported in the developing countries in Asia and Africa. Viral hepatitis, alcoholism as well as dietary carcinogens, such as aflatoxins and nitrosoamines, contribute to HCC. Surgical resection is the best treatment for early HCC, and Chinese medicine is one of the main measures for the treatment of advanced HCC. Numerous studies show that curcumin has anti-cancer, anti-oxidant and anti-inflammatory properties. This article will discuss the mechanisms behind anti-cancer effects of curcumin in HCC.

Antitumor activity of caffeic acid 3,4-dihydroxyphenethyl ester and its pharmacokinetic and metabolic properties

Caffeic acid 3,4-dihydroxyphenethyl ester (CADPE), a natural polyphenol from Sarcandra glabra, has potent in vitro anticancer activity through multiple targets. This study investigated its in vivo anticancer efficacy and its pharmacokinetic and metabolic characteristics. CADPE at any of the dosage regimes (ip 2.5 mg/kg at an interval of 7 h, 12 h, or 24 h for eight days) significantly decreased tumor growth in hepatoma H22 and sarcoma S180 tumor-bearing mice. CADPE also significantly inhibited H22-induced acute ascites development. The in vivo anticancer efficacies of CADPE in these tumor models were equivalent to those of 5-fluorouracil (10 mg/kg, ip) and cyclophosphamide (10 mg/kg, ip), and CADPE did not show any toxicity. A high performance liquid chromatography method with the aid of liquid chromatography/mass spectrometry was established and validated for the pharmacokinetic and metabolic studies of CADPE. CADPE was detected in blood and the organs including liver, kidney, heart, spleen, and brain 1 min after tail intravenous administration, indicating that CADPE was able to quickly distribute to these organs. CADPE was quickly hydrolyzed both in mice and in vitro mice plasma, but was much stable in vitro human plasma, suggesting a better bioavailability of CADPE in human than in mice. The major metabolites of CADPE in mice were caffeic acid, hydroxytyrosol, and a CADPE glucuronide. This was the first time to reveal the pharmacokinetic and metabolic characteristics of CADPE. Taken together, CADPE had potent in vivo antitumor activity and was able to rapidly reach the body organs and to be hydrolyzed in blood to anticancer agents of caffeic acid and hydroxytyrosol. This study suggested that CADPE has the potential for the treatment of cancers and is worthy of further study.

Photodynamic potential of curcumin and blue LED against Streptococcus mutans in a planktonic culture

BACKGROUND

The photodynamic therapy (PDT) involves the use of light of specific wavelength to activate a nontoxic photosensitizing agent or dye in the presence of oxygen for eradication of target cells. In dentistry, this therapy is used to suppress the growth of microorganisms involved directly with dental decay and periodontitis process. There are evidences that curcumin dye is able to control microbial activity when illuminated with specific wavelength. The purpose of this study was to evaluate the in vitro efficacy of PDT using curcumin dye (Cur-C) in combination with a blue LED (L) device on a planktonic model of Streptococcus mutans (S. mutans).

METHODS

Suspensions (0.5 mL) containing S. mutans at 1×10(7)CFU mL(-1) were prepared and divided into 4 groups: Group C-L- (control: no treatment and 1 experimental condition), Group C+L- (curcumin at 3 different concentrations: 2000; 4000 and 8000 μM and 3 experimental conditions), Group C-L+ (LED at 3 different dosages: 24, 48 and 72 Jcm(-2) and 3 experimental conditions), and Group C+L+ (PDT group: curcumin at respective concentrations combined to LED dosages and 9 experimental conditions). Samples of each experimental condition were cultured in Petri dishes of BHI agar. Incubation in micro-aerophilia at 37°C for 48 h was performed for subsequent visual counting of CFU/mL. Data were transformed into log10 and analyzed by two-way ANOVA and Tukey's test at p<0.05.

RESULTS

Group C+L+, in specific experimental conditions, demonstrated a log bacterial reduction 70% higher than Group C-L-. Both groups C-L+ and C+L- presented a slight decrease in log bacterial counting.

CONCLUSION

This in vitro method was able to reduce the number of S. mutans in a planktonic suspension.

Curcumin modulates DNA methylation in colorectal cancer cells

Aim

Recent evidence suggests that several dietary polyphenols may exert their chemopreventive effect through epigenetic modifications. Curcumin is one of the most widely studied dietary chemopreventive agents for colon cancer prevention, however, its effects on epigenetic alterations, particularly DNA methylation, remain unclear. Using systematic genome-wide approaches, we aimed to elucidate the effect of curcumin on DNA methylation alterations in colorectal cancer cells.

Materials and Methods

To evaluate the effect of curcumin on DNA methylation, three CRC cell lines, HCT116, HT29 and RKO, were treated with curcumin. 5-aza-2′-deoxycytidine (5-aza-CdR) and trichostatin A treated cells were used as positive and negative controls for DNA methylation changes, respectively. Methylation status of LINE-1 repeat elements, DNA promoter methylation microarrays and gene expression arrays were used to assess global methylation and gene expression changes. Validation was performed using independent microarrays, quantitative bisulfite pyrosequencing, and qPCR.

Results

As expected, genome-wide methylation microarrays revealed significant DNA hypomethylation in 5-aza-CdR-treated cells (mean β-values of 0.12), however, non-significant changes in mean β-values were observed in curcumin-treated cells. In comparison to mock-treated cells, curcumin-induced DNA methylation alterations occurred in a time-dependent manner. In contrast to the generalized, non-specific global hypomethylation observed with 5-aza-CdR, curcumin treatment resulted in methylation changes at selected, partially-methylated loci, instead of fully-methylated CpG sites. DNA methylation alterations were supported by corresponding changes in gene expression at both up- and down-regulated genes in various CRC cell lines.

Conclusions

Our data provide previously unrecognized evidence for curcumin-mediated DNA methylation alterations as a potential mechanism of colon cancer chemoprevention. In contrast to non-specific global hypomethylation induced by 5-aza-CdR, curcumin-induced methylation changes occurred only in a subset of partially-methylated genes, which provides additional mechanistic insights into the potent chemopreventive effect of this dietary nutraceutical.

In-vitro anti-viral screening and cytotoxicity evaluation of copper-curcumin complex

Multiple therapeutic activities attributed to curcumin deliver a challenge to explore its hidden qualities. Structural features set an opportunity to chelate metal ions and enhance the therapeutics in a specified direction. A metallo-herbal complex (MHco) of curcumin with copper (Cu(2+)) ions was synthesized and characterized by various spectroscopy techniques. It was screened for its antiviral activity and cytotoxicity. Studies revealed that the synthesized compound has good microbicidal activity and would be utilized for the development of vaginal microbicidal gel against viral infections.

Dehydrozingerone, a structural analogue of curcumin, induces cell-cycle arrest at the G2/M phase and accumulates intracellular ROS in HT-29 human colon cancer cells

Dehydrozingerone (1) is a pungent constituent present in the rhizomes of ginger (Zingiber officinale) and belongs structurally to the vanillyl ketone class. It is a representative of half the chemical structure of curcumin (2), which is an antioxidative yellow pigment obtained from the rhizomes of turmeric (Curcuma longa). Numerous studies have suggested that 2 is a promising phytochemical for the inhibition of malignant tumors, including colon cancer. On the other hand, there have been few studies on the potential antineoplastic properties of 1, and its mode of action based on a molecular mechanism is little known. Therefore, the antiproliferative effects of 1 were evaluated against HT-29 human colon cancer cells, and it was found that 1 dose-dependently inhibited growth at the G2/M phase with up-regulation of p21. Dehydrozingerone additionally led to the accumulation of intracellular ROS, although most radical scavengers could not clearly repress the cell-cycle arrest at the G2/M phase. Furthermore, two synthetic isomers of 1 (iso-dehydrozingerone, 3, and ortho-dehydrozingerone, 4) were also examined. On comparing of their activities, accumulation of intracellular ROS was found to be interrelated with growth-inhibitory effects. These results suggest that analogues of 1 may be potential chemotherapeutic agents for colon cancer.

Effects of curcumin on the proliferation and mineralization of human osteoblast-like cells: implications of nitric oxide

Curcumin (diferuloylmethane) is found in the rhizomes of the turmeric plant (Curcuma longa L.) and has been used for centuries as a dietary spice and as a traditional Indian medicine used to treat different conditions. At the cellular level, curcumin modulates important molecular targets: transcription factors, enzymes, cell cycle proteins, cytokines, receptors and cell surface adhesion molecules. Because many of the curcumin targets mentioned above participate in the regulation of bone remodeling, curcumin may affect the skeletal system. Nitric oxide (NO) is a gaseous molecule generated from l-arginine during the catalization of nitric oxide synthase (NOS), and it plays crucial roles in catalization and in the nervous, cardiovascular and immune systems. Human osteoblasts have been shown to express NOS isoforms, and the exact mechanism(s) by which NO regulates bone formation remain unclear. Curcumin has been widely described to inhibit inducible nitric oxide synthase expression and nitric oxide production, at least in part via direct interference in NF-κB activation. In the present study, after exposure of human osteoblast-like cells (MG-63), we have observed that curcumin abrogated inducible NOS expression and decreased NO levels, inhibiting also cell prolifieration. This effect was prevented by the NO donor sodium nitroprusside. Under osteogenic conditions, curcumin also decreased the level of mineralization. Our results indicate that NO plays a role in the osteoblastic profile of MG-63 cells.

Therapeutic roles of curcumin: lessons learned from clinical trials

Extensive research over the past half century has shown that curcumin (diferuloylmethane), a component of the golden spice turmeric (Curcuma longa), can modulate multiple cell signaling pathways. Extensive clinical trials over the past quarter century have addressed the pharmacokinetics, safety, and efficacy of this nutraceutical against numerous diseases in humans. Some promising effects have been observed in patients with various pro-inflammatory diseases including cancer, cardiovascular disease, arthritis, uveitis, ulcerative proctitis, Crohn's disease, ulcerative colitis, irritable bowel disease, tropical pancreatitis, peptic ulcer, gastric ulcer, idiopathic orbital inflammatory pseudotumor, oral lichen planus, gastric inflammation, vitiligo, psoriasis, acute coronary syndrome, atherosclerosis, diabetes, diabetic nephropathy, diabetic microangiopathy, lupus nephritis, renal conditions, acquired immunodeficiency syndrome, β-thalassemia, biliary dyskinesia, Dejerine-Sottas disease, cholecystitis, and chronic bacterial prostatitis. Curcumin has also shown protection against hepatic conditions, chronic arsenic exposure, and alcohol intoxication. Dose-escalating studies have indicated the safety of curcumin at doses as high as 12 g/day over 3 months. Curcumin's pleiotropic activities emanate from its ability to modulate numerous signaling molecules such as pro-inflammatory cytokines, apoptotic proteins, NF-κB, cyclooxygenase-2, 5-LOX, STAT3, C-reactive protein, prostaglandin E(2), prostate-specific antigen, adhesion molecules, phosphorylase kinase, transforming growth factor-β, triglyceride, ET-1, creatinine, HO-1, AST, and ALT in human participants. In clinical trials, curcumin has been used either alone or in combination with other agents. Various formulations of curcumin, including nanoparticles, liposomal encapsulation, emulsions, capsules, tablets, and powder, have been examined. In this review, we discuss in detail the various human diseases in which the effect of curcumin has been investigated.

What is integrative oncology and can it help my patients?

Integrative oncology lends itself to the comprehensive practice of gynecologic oncology with multiple tools and interventions that can impact on QoL and survival. However, there remains a paucity of well-designed, well-powered randomized control trials on various CAM modalities for gynecologic cancer patients. The reasons for the lack of level 1 evidence include the nascent state of integrative medicine as a science, the limitations on CAM funding, the relative lack of integration of CAM practitioners into the oncology community, and absence of strict regulation of herbs and supplements by the US FDA. The use of CAM as adjunctive therapies will likely continue given the patient-driven trends to date, and given the evidence for at least safety and potentially efficacy, our patients deserve our willingness to use all possible approaches to improving their outcomes. Continued evolution of our ability to specifically measure and describe QoL will further our ability to hone in on domains most important to patients and their survival and allow practitioners to make patient-specific recommendations. Multimodal programs that include physical activity, stress management, and diet have the potential to address demonstrated deficits in PWB and FWB in ovarian cancer patients which suggests a model of collaborative gynecologic oncology care). Integrative oncology represents a holistic approach to patient care whose goal is maximization of patient quantity and quality of life. Patients can achieve this optimal outcome through the synergy of conventional care, integrative modalities, lifestyle modifications, and supportive care. Refer to Table 4 for a listing of integrated medicine Internet resources.

Inhibition by curcumin of multiple sites of the transforming growth factor-beta1 signalling pathway ameliorates the progression of liver fibrosis induced by carbon tetrachloride in rats

Background

At present there is no effective and accepted therapy for hepatic fibrosis. Transforming growth factor (TGF)-β1 signaling pathway contributes greatly to hepatic fibrosis. Reducing TGF-β synthesis or inhibiting components of its complex signaling pathway represent important therapeutic targets. The aim of the study was to investigate the effect of curcumin on liver fibrosis and whether curcumin attenuates the TGF-β1 signaling pathway.

Methods

Sprague–Dawley rat was induced liver fibrosis by carbon tetrachloride (CCl₄) for six weeks together with or without curcumin, and hepatic histopathology and collagen content were employed to quantify liver necro-inflammation and fibrosis. Moreover, the mRNA and protein expression levels of TGF-β1, Smad2, phosphorylated Smad2, Smad3, Smad7 and connective tissue growth factor (CTGF) were determined by quantitative real time-PCR, Western blot, or immunohistochemistry.

Results

Rats treated with curcumin improved liver necro-inflammation, and reduced liver fibrosis in association with decreased α-smooth muscle actin expression, and decreased collagen deposition. Furthermore, curcumin significantly attenuated expressions of TGFβ1, Smad2, phosphorylated Smad2, Smad3, and CTGF and induced expression of the Smad7.

Conclusions

Curcumin significantly attenuated the severity of CCl₄-induced liver inflammation and fibrosis through inhibition of TGF-β1/Smad signalling pathway and CTGF expression. These data suggest that curcumin might be an effective antifibrotic drug in the prevention of liver disease progression.

Antifibrotic effect of curcumin in TGF-β 1-induced myofibroblasts from human oral mucosa

BACKGROUND

Myofibroblasts play an important role in the development of oral submucous fibrosis (OSF). In the current study, we investigate the effect of curcumin on growth and apoptosis of myofibroblasts derived from human oral mucosa.

METHODS

Myofibroblasts were generated by incubating fibroblasts, obtained from human oral mucosa, with transforming growth factor-β 1 (TGF-β 1). MTT, PI staining, and FACS assays were used to investigate curcumin's effect on proliferation and cell cycle of fibroblasts and myofibroblasts. Annexin V/PI binding and FACS assays were used to examine apoptosis of myofibroblasts, Western blotting to determine the levels of Bcl-2 and Bax, and enzyme-linked immunosorbant assay was employed to examine the levels of collagen type I and III in the supernatants of myofibroblasts.

RESULTS

Curcumin inhibits proliferation of fibroblasts and myofibroblasts; it also disturbs the cell cycle, induces apoptosis and decreases the generation of collagen type I and III in myofibroblasts, which are more sensitive to its effects than fibroblasts. Curcumin induces apoptosis in myofibroblasts by down-regulating the Bcl-2/ Bax ratio.

CONCLUSION

Our results demonstrate the antifibrotic effect of curcumin in vitro. It may therefore be a candidate for the treatment of OSF.

Curcumin attenuates β-catenin signaling in prostate cancer cells through activation of protein kinase D1

Prostate cancer is the most commonly diagnosed cancer affecting 1 in 6 males in the US. Understanding the molecular basis of prostate cancer progression can serve as a tool for early diagnosis and development of novel treatment strategies for this disease. Protein Kinase D1 (PKD1) is a multifunctional kinase that is highly expressed in normal prostate. The decreased expression of PKD1 has been associated with the progression of prostate cancer. Therefore, synthetic or natural products that regulate this signaling pathway can serve as novel therapeutic modalities for prostate cancer prevention and treatment. Curcumin, the active ingredient of turmeric, has shown anti-cancer properties via modulation of a number of different molecular pathways. Herein, we have demonstrated that curcumin activates PKD1, resulting in changes in β-catenin signaling by inhibiting nuclear β-catenin transcription activity and enhancing the levels of membrane β-catenin in prostate cancer cells. Modulation of these cellular events by curcumin correlated with decreased cell proliferation, colony formation and cell motility and enhanced cell-cell aggregation in prostate cancer cells. In addition, we have also revealed that inhibition of cell motility by curcumin is mediated by decreasing the levels of active cofilin, a downstream target of PKD1. The potent anti-cancer effects of curcumin in vitro were also reflected in a prostate cancer xenograft mouse model. The in vivo inhibition of tumor growth also correlated with enhanced membrane localization of β-catenin. Overall, our findings herein have revealed a novel molecular mechanism of curcumin action via the activation of PKD1 in prostate cancer cells.

A randomized, pilot study to assess the efficacy and safety of curcumin in patients with active rheumatoid arthritis

Curcumin is known to possess potent antiinflammatory and antiarthritic properties. This pilot clinical study evaluated the safety and effectiveness of curcumin alone, and in combination with diclofenac sodium in patients with active rheumatoid arthritis (RA). Forty-five patients diagnosed with RA were randomized into three groups with patients receiving curcumin (500 mg) and diclofenac sodium (50 mg) alone or their combination. The primary endpoints were reduction in Disease Activity Score (DAS) 28. The secondary endpoints included American College of Rheumatology (ACR) criteria for reduction in tenderness and swelling of joint scores. Patients in all three treatment groups showed statistically significant changes in their DAS scores. Interestingly, the curcumin group showed the highest percentage of improvement in overall DAS and ACR scores (ACR 20, 50 and 70) and these scores were significantly better than the patients in the diclofenac sodium group. More importantly, curcumin treatment was found to be safe and did not relate with any adverse events. Our study provides the first evidence for the safety and superiority of curcumin treatment in patients with active RA, and highlights the need for future large-scale trials to validate these findings in patients with RA and other arthritic conditions.

Synergism of plant-derived polyphenols in adipogenesis: perspectives and implications

Dietary polyphenols may exert their pharmacological effect via synergistic interactions with multiple targets. Putative effects of polyphenols in the management of obesity should be primarily evaluated in adipose tissue and consequently in well-documented cell model. We used Hibiscus sabdariffa (HS), a widely recognised medicinal plant, as a source of polyphenols with a number of salutary effects previously reported. We present here the full characterisation of bioactive components of HS aqueous extracts and document their effects in a model of adipogenesis from 3T3-L1 cells and in hypertrophic and insulin-resistant adipocytes. Aqueous extracts were up to 100 times more efficient in inhibiting triglyceride accumulation when devoid of fibre and polysaccharides. Significant differences were also observed in reactive oxygen species generation and adipokine secretion. We also found that, when polyphenols were fractionated and isolated, the benefits of the whole extract were greater than the sum of its parts, which indicated a previously unnoticed synergism. In conclusion, polyphenols have interactive and complementary effects, which suggest a possible application in the management of complex diseases and efforts to isolate individual components might be irrelevant for clinical medicine and/or human nutrition.

Are there new therapeutic options for treating lung cancer based on herbal medicines and their metabolites?

ETHONOPHARMACOLOGICAL RELEVANCE: Lung cancer is one of the most lethal cancers in terms of mortality and incidence worldwide. Despite intensive research and investigation, treatment of lung cancer is still unsatisfactory due to adverse effects and multidrug resistance. Recently, herbal drugs have been recognized as one of attractive approaches for lung cancer therapy with little side effects. Furthermore, there are evidences that various herbal medicines have proven to be useful and effective in sensitizing conventional agents, prolonging survival time, preventing side effects of chemotherapy, and improving quality of life (QoL) in lung cancer patients.

AIM AND METHODS OF THE STUDY

Nevertheless, the underlying molecular targets and efficacy of herbal medicines in lung cancer treatment still remain unclear. Thus, we reviewed traditionally used herbal medicines and their phytochemicals with antitumor activity against lung cancer from peer-reviewed papers through Scientific Database Medline, Scopus and Google scholar.

CONCLUSIONS

We suggest that herbal medicines and phytochemicals can be useful anti-cancer agents for lung cancer treatment by targeting molecular signaling involved in the regulation of angiogenesis, metastasis and severe side effects, only provided quality control and reproducibility issues were solved.

Natural polyphenols in cancer therapy

Natural polyphenols are secondary metabolites of plants involved in defense against different types of stress. Extracts containing these compounds have been used for thousands of years in traditional eastern medicine. Polyphenols act on multiple targets in pathways and mechanisms related to carcinogenesis, tumor cell proliferation and death, inflammation, metastatic spread, angiogenesis, or drug and radiation resistance. Nevertheless, reported effects claimed for polyphenols are controversial, since correlations between in vitro effects and in vivo evidence are poorly established. The main discrepancy between health claims versus clinical observations is the frequent use of nonphysiologically relevant concentrations of these compounds and their metabolites in efficacy and mechanistic studies. The present review will discuss how in vivo administration correlates with polyphenol metabolism, toxicity, and bioavailability. Analysis of the general application of polyphenols in cancer therapy will be complemented by potential applications in the therapy of specific tumors, including melanoma, colorectal and lung cancers. Possible pharmaceutical formulations, structural modifications, combinations, and delivery systems aimed to increase bioavailability and/or biological effects will be discussed. Final remarks will include recommendations for future research and developments.

Curcumin nanoformulations: a future nanomedicine for cancer

Curcumin, a natural diphenolic compound derived from turmeric Curcuma longa, has proven to be a modulator of intracellular signaling pathways that control cancer cell growth, inflammation, invasion and apoptosis, revealing its anticancer potential. In this review, we focus on the design and development of nanoparticles, self-assemblies, nanogels, liposomes and complex fabrication for sustained and efficient curcumin delivery. We also discuss the anticancer applications and clinical benefits of nanocurcumin formulations. Only a few novel multifunctional and composite nanosystem strategies offer simultaneous therapy as well as imaging characteristics. We also summarize the challenges to developing curcumin delivery platforms and up-to-date solutions for improving curcumin bioavailability and anticancer potential for therapy.

3,5-bis(2,4-difluorobenzylidene)-4-piperidone, a novel compound that affects pancreatic cancer growth and angiogenesis

Dysregulated Notch signaling plays an important role in the progression of cancer. Notch signaling affects tumor growth and angiogenesis through the actions of its ligand Jagged-1. In this study, we developed a novel compound 3,5-bis(2,4-difluorobenzylidene)-4-piperidone (DiFiD) and determined that it inhibits cancer cell growth and its effects on Notch signaling. Intraperitoneal administration of DiFiD significantly suppressed growth of pancreatic cancer tumor xenografts. There was a reduction in CD31-positive blood vessels, suggesting that there was an effect on angiogenesis. In vitro, DiFiD inhibited the proliferation of various human and mouse pancreatic cancer cells while increasing activated caspase-3. Cell-cycle analyses showed that DiFiD induced G(2)-M arrest and decreased the expression of cell-cycle-related proteins cyclin A1 and D1 while upregulating cyclin-dependent kinase inhibitor p21WAF1. We next determined the mechanism of action. DiFiD reduced Notch-1 activation, resulting in reduced expression of its downstream target protein Hes-1. We further determined that the reduced Notch-1 activation was due to reduction in the ligand Jagged-1 and two critical components of the γ-secretase enzyme complex presenilin-1 and nicastrin. Ectopic expression of the Notch intracellular domain rescued the cells from DiFiD-mediated growth suppression. DiFiD-treated tumor xenografts also showed reduced levels of Jagged-1 and the γ-secretase complex proteins presenilin-1 and nicastrin. Taken together, these data suggest that DiFiD is a novel potent therapeutic agent that can target different aspects of the Notch signaling pathway to inhibit both tumor growth and angiogenesis.

Rescue of photoreceptor degeneration by curcumin in transgenic rats with P23H rhodopsin mutation

The P23H mutation in the rhodopsin gene causes rhodopsin misfolding, altered trafficking and formation of insoluble aggregates leading to photoreceptor degeneration and autosomal dominant retinitis pigmentosa (RP). There are no effective therapies to treat this condition. Compounds that enhance dissociation of protein aggregates may be of value in developing new treatments for such diseases. Anti-protein aggregating activity of curcumin has been reported earlier. In this study we present that treatment of COS-7 cells expressing mutant rhodopsin with curcumin results in dissociation of mutant protein aggregates and decreases endoplasmic reticulum stress. Furthermore we demonstrate that administration of curcumin to P23H-rhodopsin transgenic rats improves retinal morphology, physiology, gene expression and localization of rhodopsin. Our findings indicate that supplementation of curcumin improves retinal structure and function in P23H-rhodopsin transgenic rats. This data also suggest that curcumin may serve as a potential therapeutic agent in treating RP due to the P23H rhodopsin mutation and perhaps other degenerative diseases caused by protein trafficking defects.

Proteomic identification of differentially expressed proteins in curcumin-treated MCF-7 cells

Curcumin (CM), a well-known dietary pigment derived from Curcuma longa L., possess anticancer activities against a variety of tumors including human breast carcinoma. In combination with docetaxel, CM has been used in breast cancer management in the clinic. In order to explore the possible mechanism of anticancer activity of CM, in the present study, we aimed to identify proteins involved in the anticancer activity of CM in human breast cancer cell line MCF-7 using the two-dimensional electrophoresis (2-DE)-based proteomic analysis. MCF-7 cells were cultured at 37°C in an atmosphere of 5.0% CO(2). All the following experiments were repeated three times. Cell viability assay showed that after a 48-h incubation CM dose-dependently inhibited cell growth with an IC(50) value of 47.42 μM. Treatment of CM at 47.42 μM for 48 h induced apoptosis as determined by nuclear morphologic changes of Hoechst stained cells and flow cytometric analysis of Annexin V-FITC/PI stained cells. Proteomic analysis identified 12 differentially expressed proteins which contributed to multiple functional activities such as DNA transcription, mRNA splicing and translation, amino acid synthesis, protein synthesis, folding and degradation, lipid metabolism, glycolysis, and cell motility. Among them 7 proteins were up-regulated and 5 down-regulated. The up-regulated ones were verified by quantitative real-time PCR. The down-regulated proteins, TDP-43, SF2/ASF and eIF3i, as well as up-regulated ones, 3-PGDH, ERP29, and platelet-activating factor acetylhydrolase IB subunit beta positively contribute to the anticancer activity of CM in MCF-7 cells. These molecules are implicated in the bioactivities of CM for the first time. The findings of this study would shed new insights for systematically understanding the mechanisms of CM in breast cancer intervention.

Comparative absorption of a standardized curcuminoid mixture and its lecithin formulation

The relative absorption of a standardized curcuminoid mixture and its corresponding lecithin formulation (Meriva) was investigated in a randomized, double-blind, crossover human study. Clinically validated dosages were used for both products, and plasma levels of all three major curcuminoids [curcumin (1a), demethoxycurcumin (1b), and bisdemethoxycurcumin (1c)] were evaluated. Total curcuminoid absorption was about 29-fold higher for Meriva than for its corresponding unformulated curcuminoid mixture, but only phase-2 metabolites could be detected, and plasma concentrations were still significantly lower than those required for the inhibition of most anti-inflammatory targets of curcumin. Remarkably, phospholipid formulation increased the absorption of demethoxylated curcuminoids much more than that of curcumin (1a), with significant differences in plasma curcuminoid profile between Meriva and its corresponding unformulated curcuminoid mixture. Thus, the major plasma curcuminoid after administration of Meriva was not curcumin (1a), but demethoxycurcumin (1b), a more potent analogue in many in vitro anti-inflammatory assays. The improved absorption, and possibly also a better plasma curcuminoid profile, might underlie the clinical efficacy of Meriva at doses significantly lower than unformulated curcuminoid mixtures.

RNA binding protein CUGBP2/CELF2 mediates curcumin-induced mitotic catastrophe of pancreatic cancer cells

BACKGROUND

Curcumin inhibits the growth of pancreatic cancer tumor xenografts in nude mice; however, the mechanism of action is not well understood. It is becoming increasingly clear that RNA binding proteins regulate posttranscriptional gene expression and play a critical role in RNA stability and translation. Here, we have determined that curcumin modulates the expression of RNA binding protein CUGBP2 to inhibit pancreatic cancer growth.

METHODOLOGY/PRINCIPAL FINDINGS

In this study, we show that curcumin treated tumor xenografts have a significant reduction in tumor volume and angiogenesis. Curcumin inhibited the proliferation, while inducing G2-M arrest and apoptosis resulting in mitotic catastrophe of various pancreatic cancer cells. This was further confirmed by increased phosphorylation of checkpoint kinase 2 (Chk2) protein coupled with higher levels of nuclear cyclin B1 and Cdc-2. Curcumin increased the expression of cyclooxygenase-2 (COX-2) and vascular endothelial growth factor (VEGF) mRNA, but protein levels were lower. Furthermore, curcumin increased the expression of RNA binding proteins CUGBP2/CELF2 and TIA-1. CUGBP2 binding to COX-2 and VEGF mRNA was also enhanced, thereby increasing mRNA stability, the half-life changing from 30 min to 8 h. On the other hand, silencer-mediated knockdown of CUGBP2 partially restored the expression of COX-2 and VEGF even with curcumin treatment. COX-2 and VEGF mRNA levels were reduced to control levels, while proteins levels were higher.

CONCLUSION/SIGNIFICANCE

Curcumin inhibits pancreatic tumor growth through mitotic catastrophe by increasing the expression of RNA binding protein CUGBP2, thereby inhibiting the translation of COX-2 and VEGF mRNA. These data suggest that translation inhibition is a novel mechanism of action for curcumin during the therapeutic intervention of pancreatic cancers.

Chemopreventive potential of natural compounds in head and neck cancer

Head and neck squamous cell carcinoma (HNSCC) is one of the most fatal cancers worldwide. Despite advances in the management of HNSCC, the overall survival for patients has not improved significantly due to advanced stages at diagnosis, high recurrence rate after surgical removal, and second primary tumor development, which underscore the importance of novel strategies for cancer prevention. Cancer chemoprevention, the use of natural or synthetic compounds to prevent, arrest, or reverse the process of carcinogenesis at its earliest stages, aims to reverse premalignancies and prevent second primary tumors. Genomics and proteomics information including initial mutation, cancer promotion, progression, and susceptibility has brought molecularly targeted therapies for drug development. The development of preventive approaches using specific natural or synthetic compounds, or both, requires a depth of understanding of the cross-talk between cancer signaling pathways and networks to retain or enhance chemopreventive activity while reducing known toxic effects. Many natural dietary compounds have been identified with multiple molecular targets, effective in the prevention and treatment of cancer. This review describes recent advances in the understanding of the complex signaling networks driving cancer progression and of molecularly targeted natural compounds under preclinical and clinical investigation.

Nutraceutical use in late-stage cancer

Access to a wealth of information on the internet has led many cancer patients to use complementary methods as an adjunct to traditional therapy for cancer, with, and more often, without informing their primary caregiver. Of the common complementary modalities, the use of dietary supplements appears to be highly prevalent in patients in active treatment for cancer, and later in cancer survivors. Emerging research suggests that some plant-based agents may, indeed, impact late-stage cancer, influencing molecular processes corrupted by tumor cells to evade detection, expand clonally, and invade surrounding tissues. The intent of this article is to review some of the current science underpinning the use of nutraceuticals in the latter stages of cancer.

Heat-solubilized curry spice curcumin inhibits antibody-antigen interaction in in vitro studies: a possible therapy to alleviate autoimmune disorders

Chronic and complex autoimmune diseases, currently treated palliatively with immunosuppressives, require multi-targeted therapy for greater effectiveness. The naturally occurring polyphenol curcumin has emerged as a powerful "nutraceutical" that interacts with multiple targets to regress diseases safely and inexpensively. Up to 8 g/day of curcumin for 18 months was non-toxic to humans. However, curcumin's utility is limited by its aqueous insolubility. We have demonstrated a heat-mediated 12-fold increase in curcumin's aqueous solubility. Here, we show by SDS-PAGE and surface plasmon resonance that heat-solubilized curcumin binds to proteins. Based on this binding we hypothesized that heat-solubilized curcumin or turmeric would prevent autoantibody targeting of cognate autoantigens. Heat-solubilized curcumin/turmeric significantly decreased binding of autoantibodies from Sjögren's syndrome (up to 43/70%, respectively) and systemic lupus erythematosus (up to 52/70%, respectively) patients as well as an animal model of Sjögren's syndrome (up to 50/60%, respectively) to their cognate antigens. However, inhibition was not specific to autoimmunity. Heat-solubilized curcumin/turmeric also inhibited binding of commercial polyclonal anti-spectrin to spectrin (50/56%, respectively). Thus, we suggest that the multifaceted heat-solubilized curcumin can ameliorate autoimmune disorders. In addition, the non-toxic curcumin could serve as a new protein stain in SDS-PAGE even though it is less sensitive than the Coomassie system which involves toxic chemicals.

Evaluation of novel alginate foams as drug delivery systems in antimicrobial photodynamic therapy (aPDT) of infected wounds--an in vitro study: studies on curcumin and curcuminoides XL

The aim of the present study was to incorporate a model water-insoluble photosensitizer, curcumin, in novel alginate foams, further to evaluate the suitability of the curcumin loaded foams in antimicrobial photodynamic therapy of infected wounds. Six foam formulations were prepared and characterized with respect to physical characteristics, in vitro release and storage- and photo-stability of curcumin. One formulation was sterilized (gamma-sterilization). The foams contained hydroxypropyl-beta-cyclodextrins or hydroxypropyl-gamma-cyclodextrins as solubilizers of curcumin. A reference foam without cyclodextrins was prepared with PEG 400 as the solubilizer. At a curcumin load of 0.153% (w/w), the water insoluble photosensitizer was uniformly distributed in the hydrophilic foams matrix. All foams were easy to handle, flexible and hydrated rapidly in a model physiological fluid. Release of curcumin in its monomeric form was demonstrated in vitro and found to be dependent on the type and amount of cyclodextrins in the formulation. Curcumin was stable during storage, but susceptible to photodegradation in the foams, especially when the formulations contain PEG 400 or hydroxypropyl-gamma-cyclodextrins. Curcumin did not degrade after gamma-sterilization, however a decrease in the in vitro release rate of curcumin and changes in the foams physical characteristics were detected.

Curcumin's effect on intestinal inflammation and tumorigenesis in the ApcMin/+ mouse

Curcumin's benefits on tumorigenesis are thought to be mediated by its antiinflammatory activity; however, these effects have not been well characterized in a mouse model of colon cancer. We examined the effects of curcumin on intestinal inflammation in the Apc(Min/+) mouse. Apc(Min/+) mice were given a placebo or curcumin (2%) diet from 4 to 18 weeks of age (n = 10/group). C57BL/6 mice were used as a wild-type control (n = 10/group). Intestines were analyzed for polyp burden (sections 1, 4, and 5) and for mRNA expression, and concentration of interleukin (IL)-1β, IL-6, tumor necrosis factor-α, and chemokine ligand 2 (CCL2) (sections 2 and 3). Plasma was collected for concentration of CCL2. Curcumin decreased total intestinal polyps by 75% (P < 0.05) in all size categories [>2 mm (65%), 1-2 mm (72%), <1 mm (82%); P < 0.05]. mRNA expression of IL-1β, IL-6, tumor necrosis factor-α, and CCL2 was elevated (P < 0.05) and curcumin blunted this increase (P < 0.05). Protein concentration of IL-1β, IL-6 (section 3), and CCL2 was increased (P < 0.05) and curcumin reduced this response for IL-1β (section 2) and CCL2 (P < 0.05). Curcumin also offset the increase in plasma CCL2 (P < 0.05). The benefits of curcumin in colon cancer may be at least in part mediated by its antiinflammatory activity.

Cancer stem cells: a novel paradigm for cancer prevention and treatment

Cancer is the second leading cause for mortality in US only after heart disease and lacks a good or effective therapeutic paradigm. Despite the emergence of new, targeted agents and the use of various therapeutic combinations, none of the treatment options available is curative in patients with advanced cancer. A growing body of evidence is supporting the idea that human cancers can be considered as a stem cell disease. Malignancies are believed to originate from a fraction of cancer cells that show self renewal and pluripotency and are capable of initiating and sustaining tumor growth. The cancer-initiating cells or cancer stem cells were originally identified in hematological malignancies but is now being recognized in several solid tumors. The hypothesis of stem cell-driven tumorigenesis raises questions as to whether the current treatments, most of which require rapidly dividing cells are able to efficiently target these slow cycling tumorigenic cells. Recent characterization of cancer stem cells should lead to the identification of key signaling pathways that may make cancer stem cells vulnerable to therapeutic interventions that target drug-effluxing capabilities, anti-apoptotic mechanisms, and induction of differentiation. Dietary phytochemicals possess anti-cancer properties and represent a promising approach for the prevention and treatment of many cancers.

Neuroprotective herbs and foods from different traditional medicines and diets

Plant secondary metabolites include an array of bioactive constituents form both medicinal and food plants able to improve human health. The exposure to these phytochemicals, including phenylpropanoids, isoprenoids and alkaloids, through correct dietary habits, may promote health benefits, protecting against the chronic degenerative disorders mainly seen in Western industrialized countries, such as cancer, cardiovascular and neurodegenerative diseases. In this review, we briefly deal with some plant foods and herbs of traditional medicines and diets, focusing on their neuroprotective active components. Because oxidative stress and neuroinflammation resulting from neuroglial activation, at the level of neurons, microglial cells and astrocytes, are key factors in the etiopathogenesis of both neurodegenerative and neurological diseases, emphasis will be placed on the antioxidant and anti-inflammatory activity exerted by specific molecules present in food plants or in remedies prescribed by herbal medicines.

Reduction of periductal fibrosis in liver fluke-infected hamsters after long-term curcumin treatment

Chronic infection with the liver fluke, Opisthorchis viverrini, induces advanced periductal fibrosis and is a relative risk factor for cholangiocarcinoma in Southeastern Asia. We examined the reducing effect of curcumin on hepatobiliary fibrosis using O. viverrini-infected hamsters supplemented with dietary 1% curcumin (w/w) as an animal model. The expression profile of matrix metalloproteinases (MMPs) and tissue inhibitors of MMPs (TIMPs), cytokines, and collagens was assessed in relation to liver fibrosis. Histopathological studies revealed that curcumin had no effect on fibrosis at the short-term infection (21 days and 1 month); however, peribiliary fibrosis was significantly reduced after the long-term curcumin treatment for 3 months, compared to the untreated group. Expression of alpha-smooth muscle actin was associated with the reduction of liver fibrosis. A decrease in hepatic hydroxyproline level and mRNA expression of collagen I and III supported the reduction of fibrosis. The expression of TIMP-1, TIMP-2, and tumor necrosis factor-alpha genes was also decreased after curcumin treatment. In contrast, curcumin increased mRNA expression of MMP-13, MMP-7 (at 6 months), interleukin-1 beta, and transforming growth factor beta, implying that increased MMPs activity contributes to extracellular matrix degradation. These results suggest that curcumin reduces periductal fibrosis after long-term treatment by tissue resorption via inhibition of TIMPs expression and enhancement of MMPs expression mediated by cytokines. In conclusion, curcumin may serve as a promising nutraceutical agent exerting antifibrotic effect in O. viverrini-infected patients and contribute to cholangiocarcinoma prevention.

Synthesis and biological evaluation of caffeic acid 3,4-dihydroxyphenethyl ester

A high-yield synthesis of caffeic acid 3,4-dihydroxyphenethyl ester (1) has been achieved through Knoevenagel condensation of 3,4-dihydroxybenzaldehyde and 3,4-dihydroxyphenethyl monomalonate as the key step. Compound 1 was tested against a 56-cell-line cytotoxicity panel and for its free-radical-scavenging activity in the DPPH test.

Transcriptional coactivator p300 regulates glucose-induced gene expression in endothelial cells

Sustained hyperglycemia in diabetes causes alteration of a large number of transcription factors and mRNA transcripts, leading to tissue damage. We investigated whether p300, a transcriptional coactivator with histone acetyl transferase activity, regulates glucose-induced activation of transcription factors and subsequent upregulation of vasoactive factors and extracellular matrix (ECM) proteins in human umbilical vein endothelial cells (HUVECs). HUVECs were incubated in varied glucose concentrations and were studied after p300 small interfering RNA (siRNA) transfection, p300 overexpression, or incubation with the p300 inhibitor curcumin. Histone H2AX phosphorylation and lysine acetylation were examined for oxidative DNA damage and p300 activation. Screening for transcription factors was performed with the Luminex system. Alterations of selected transcription factors were validated. mRNA expression of p300, endothelin-1 (ET-1), vascular endothelial growth factor (VEGF), and fibronectin (FN) and its splice variant EDB(+)FN and FN protein production were analyzed. HUVECs in 25 mmol/l glucose showed increased p300 production accompanied by increased binding of p300 to ET-1 and FN promoters, augmented histone acetylation, H2AX phosphorylation, activation of multiple transcription factors, and increased mRNA expression of vasoactive factors and ECM proteins. p300 overexpression showed a glucose-like effect on the mRNA expression of ET-1, VEGF, and FN. Furthermore, siRNA-mediated p300 blockade or chemical inhibitor of p300 prevented such glucose-induced changes. Similar mRNA upregulation was also seen in the organ culture of vascular tissues, which was prevented by p300 siRNA transfection. Data from these studies suggest that glucose-induced p300 upregulation is an important upstream epigenetic mechanism regulating gene expression of vasoactive factors and ECM proteins in endothelial cells and is a potential therapeutic target for diabetic complications.

Control of Deneddylation by the COP9 Signalosome

The interplay between ubiquitin (Ub) family modifiers creates a regulatory network of Ub family proteins which is essential for cell growth and differentiation. One of the best studied crosstalks between Ub family modifiers is the stimulation of ubiquitination by Nedd8 (neural precursor cell expressed developmentally down regulated 8) modification. The neddylation-deneddylation pathway controls the selective ubiquitination of important cellular regulators targeted for proteolysis by the Ub proteasome system (UPS). In this process the cullin scaffolds of cullin-RING Ub ligases (CRLs) are neddylated, which allosterically activates the transfer of Ub to substrates of the CRLs. A major reaction of the regulatory network is the removal of Nedd8 by the COP9 signalosome (CSN), which converts CRLs into an inactive state. The CSN is a conserved protein complex that interacts with CRLs and possesses an intrinsic metalloprotease with a Jab1/Pad1/MPN+ (JAMM) motif responsible for deneddylation.In the present chapter we focus on the CSN-mediated deneddylation and its biological significance. We summarize latest developments on the mechanism of the CSN and its association with supercomplexes. In addition, data on the regulation of CSN-mediated deneddylation are described. Moreover, dysfunctions of the CSN and their implication in the pathogenesis of diseases are discussed.

A novel synthetic iminoquinone, BA-TPQ, as an anti-breast cancer agent: in vitro and in vivo activity and mechanisms of action

Herein, we report our examination of the anti-breast cancer activity of a novel synthetic compound, 7-(benzylamino)-1, 3, 4, 8-tetrahydropyrrolo [4, 3, 2-de]quinolin-8(1H)-one (BA-TPQ). This agent is an analog of a naturally occurring marine compound, and was found to be the most active out of more than 40 related compounds. We investigated the in vitro activity of BA-TPQ on the survival, proliferation, and apoptosis of breast cancer cells using the MTT and BrdUrd assays, and Annexin/Annexin-PI staining and flow cytometry. The in vivo anti-cancer effects of BA-TPQ were evaluated in xenograft models of breast cancer. Finally, the mechanisms of action of the compound were also assessed by cDNA microarrays, RT-PCR and Western blotting. In a dose-dependent manner, BA-TPQ inhibited cell growth and induced apoptosis and cell cycle arrest in human MCF-7 and MDA-MB-468 breast cancer cells in vitro, and showed in vivo efficacy in mice bearing MCF-7 or MDA-MB-468 xenograft tumors. We demonstrated that BA-TPQ modifies the expression of numerous molecules involved in cell cycle progression and apoptosis. Similar changes in protein expression were observed in vitro and in vivo, as determined by examination of cells and excised xenograft tumors. Our preclinical data indicate that BA-TPQ is a potential therapeutic agent for breast cancer that has multiple hormone-, Her2-, and p53-independent mechanisms of action, providing a basis for further development of the compound as a novel anticancer agent.