Colorectal cancer chemoprevention by 2 beta-cyclodextrin inclusion compounds of auraptene and 4'-geranyloxyferulic acid

The Emerging Role of Natural Products in Cancer Treatment

The exploration of natural products as potential agents for cancer treatment has garnered significant attention in recent years. In this comprehensive review, we delve into the diverse array of natural compounds, including alkaloids, carbohydrates, flavonoids, lignans, polyketides, saponins, tannins, and terpenoids, highlighting their emerging roles in cancer therapy. These compounds, derived from various botanical sources, exhibit a wide range of mechanisms of action, targeting critical pathways involved in cancer progression such as cell proliferation, apoptosis, angiogenesis, and metastasis. Through a meticulous examination of preclinical and clinical studies, we provide insights into the therapeutic potential of these natural products across different cancer types. Furthermore, we discuss the advantages and challenges associated with their use in cancer treatment, emphasizing the need for further research to optimize their efficacy, pharmacokinetics, and delivery methods. Overall, this review underscores the importance of natural products in advancing cancer therapeutics and paves the way for future investigations into their clinical applications.

Cyclodextrin based nanoparticles for smart drug delivery in colorectal cancer

The advancement of colorectal cancer (CRC) prevention, detection, and treatment is essential to ensure that survivors live longer and higher-quality lives. The field of cancer detection and therapy has undergone a revolution with the development of nanotechnology for targeted drug delivery. The significant problems with the delivery of cancer drugs are their solubility, stability, and nonspecific distribution. There is a challenge that the acidic and enzymatic environment in the digestive tract will modify or destroy the medication or the active pharmaceutical ingredient. To overcome the problems, nanoparticles have been widely employed during the past several years to increase the specificity, selectivity, and controlled release of drug delivery systems. The site-specific and targeted delivery leads to reduce toxicity and side effects. With respect to the capability and utilization of cyclodextrin-based nanoparticles in different aspects of the tumour microenvironment and gut microbiota, a survey of current research papers was conducted via looking through databases including GoogleScholar, PubMed, Web of Science, and Scopus. This review aims to summarize cutting-edge nanoparticulate-based technologies and therapies for CRC.

7-geranyloxycoumarin enhanced radiotherapy effects on human gastric adenocarcinoma cells

Background

Gastric adenocarcinoma (GA) is a serious malignancy with growing incidence and mortality rate worldwide. The objective of the present study was to determine whether 7-geranyloxycoumarin, a natural monoterpene coumarin, could induce anticancer effects, in single use and/or in combination with anticancer drugs and ionizing radiation, on GA cells.

Materials and Methods

7-geranyloxycoumarin was synthesized by a reaction between 7-hydroxycoumarin and transgeranyl bromide. MKN45 cells were treated with 7-geranyloxycoumarin, and the viability of cells was determined by resazurin. Apoptosis was then evaluated by flow cytometric analysis using annexin V and propidium iodide, and the expression of P53 and BCL2 was analyzed by quantitative polymerase chain reaction (qPCR). Combinatorial effects of 7-geranyloxycoumarin with 5-fluorouracil (5-FU), cisplatin (CDDP), and X radiation were also evaluated.

Results

Assessment of cell viability indicated that 7-geranyloxycoumarin induced its toxic effects in a time- and dose-dependent manner. This was confirmed by the detection of apoptotic cells, and qPCR results revealed a significant downregulation in BCL2 expression. Although combinatorial use of 7-geranyloxycoumarin + 5-FU or + CDDP did not improve cytotoxicity of anticancer drugs, significant increase in the effectiveness of applied radiations was detected upon pretreatment with 7-geranyloxycoumarin.

Conclusion

Our findings provide valuable insights into single and combinatorial effects of 7-geranyloxycoumarin on the GA cells.

Protection of Mitochondrial Potential and Activity by Oxyprenylated Phenylpropanoids

A series of five naturally occurring oxyprenylated phenylpropanoids, namely, the coumarins auraptene (7-geranyloxycoumarin) 1 and 7-isopentenyloxycoumarin 2, and the coumaric acid and ferulic acid derivatives, 4'-isopentenyloxycoumaric acid 3, boropinic acid 4, and 4'-geranyloxyferulic acid 5 were tested for their effects on mitochondrial functionality using the organophosphate pesticides glyphosate and chlorpyrifos, and resveratrol, as the reference. While not showing an appreciable in vitro antioxidant activity, and virtually no or a little effect on the viability of non-cancer cell lines BEAS-2B and SHSY-5Y, all phytochemicals exhibited a marked protective effect on mitochondrial potential and activity, with values that were comparable to resveratrol. Auraptene 1 and 7-isopentenyloxycoumarin 2 were seen to be the most effective secondary metabolite to this concern, in particular in being able to completely abolish the decrease of mitochondrial potential induced by increasing concentration of both glyphosate and chlorpyrifos. All the compounds tested also exhibited a protective effect on mitochondrial activity. The potency displayed will shed more light on the molecular basis of the beneficial effects of auraptene, 7-isopentenyloxycoumarin, and structurally related oxyprenylated phenylpropanoids reported to date in the literature.

Radiation Response of Human Leukemia/Lymphoma Cells was Improved by 7-Geranyloxycoumarin

Objectives

Adult T-cell leukemia/lymphoma (ATLL) is a blood neoplasm with specific geographic distribution. Although radiotherapy is a palliative treatment that provides long-term local control, single use of radiation leads to complications for patients. To introduce a novel multimodal approach against ATLL, we investigated combinatorial effects of 7-geranyloxycoumarin and radiation in vitro.

Methods

Viability of MT-2 cells was determined by resazurin assay upon administration of 7-geranyloxycoumarin alone and followed by radiation. Then, apoptosis was detected by annexin V and propidium iodide, and the expression of candidate genes was analyzed by qPCR.

Results

Findings revealed significant (P<.0001) improvement in radiation effects upon 7-geranyloxycoumarin pretreatment, most notably when cells were pretreated with 5 µg/ml 7-geranyloxycoumarin for 96 h, exposed to 6 Gy radiation and recovered for 48 h. These results were confirmed by flow cytometry, as the percentage of early and late apoptotic cells was increased after combinatorial treatment. In addition, significant (P< .0001) changes in CD44, c-MYC, cFLIPL, BMI-1, NF-κB (Rel A), and P53 expression was induced by 7-geranyloxycoumarin and radiation.

Conclusions

Current research indicated, for the first time, that combinatorial use of 7-geranyloxycoumarin and ionizing radiation could be considered as an effective therapeutic modality for ATLL.

Therapeutic Potential of Certain Terpenoids as Anticancer Agents: A Scoping Review

Cancer is a life-threatening disease and is considered to be among the leading causes of death worldwide. Chemoresistance, severe toxicity, relapse and metastasis are the major obstacles in cancer therapy. Therefore, introducing new therapeutic agents for cancer remains a priority to increase the range of effective treatments. Terpenoids, a large group of secondary metabolites, are derived from plant sources and are composed of several isoprene units. The high diversity of terpenoids has drawn attention to their potential anticancer and pharmacological activities. Some terpenoids exhibit an anticancer effect by triggering various stages of cancer progression, for example, suppressing the early stage of tumorigenesis via induction of cell cycle arrest, inhibiting cancer cell differentiation and activating apoptosis. At the late stage of cancer development, certain terpenoids are able to inhibit angiogenesis and metastasis via modulation of different intracellular signaling pathways. Significant progress in the identification of the mechanism of action and signaling pathways through which terpenoids exert their anticancer effects has been highlighted. Hence, in this review, the anticancer activities of twenty-five terpenoids are discussed in detail. In addition, this review provides insights on the current clinical trials and future directions towards the development of certain terpenoids as potential anticancer agents.

Parkinson's Disease: Is there a Role for Dietary and Herbal Supplements?

Parkinson's Disease (PD) is characterised by degeneration of the neurons of the nigrostriatal dopaminergic pathway of the brain. The pharmacological cornerstone of PD management is mainly the use of dopamine precursors, dopamine receptor agonists, and agents that inhibit the biochemical degradation of dopamine. While these drugs initially provide relief to the symptoms and improve the quality of life of the patients, progression of the underlying pathological processes, such as oxidative stress and neuroinflammation (which have been strongly associated with PD and other neurodegenerative disorders), eventually reduce their benefits, making further benefits achievable, only at high doses due to which the magnitude and frequency of side-effects are amplified. Also, while it is becoming obvious that mainstream pharmacological agents may not always provide the much-needed answer, the question remains what succour can nature provide through dietary supplements, nutraceuticals and herbal remedies? This narrative review examines current literature for evidence of the possible roles (if any) of nutraceuticals, dietary supplements and herbal remedies in the prevention or management of PD by examining how these compounds could modulate key factors and pathways that are crucial to the pathogenesis and/or progression of PD. The likely limitations of this approach and its possible future roles in PD prevention and management are also considered.

Combination of auraptene and arsenic trioxide induces apoptosis and cellular accumulation in the subG1 phase in adult T-cell leukemia cells

Objective(s):

Despite advances in the treatment of adult T-cell leukemia/lymphoma (ATLL), the survival rate of this malignancy remains significantly low. Auraptene (AUR) is a natural coumarin with broad-spectrum anticancer activities. To introduce a more effective therapeutic strategy for ATLL, we investigated the combinatorial effects of AUR and arsenic trioxide (ATO) on MT-2 cells.

Materials and Methods:

The cells were treated with different concentrations of AUR for 24, 48, and 72 hr, and viability was measured by alamarBlue assay. Then, the combination of AUR (20 μg/ml) and ATO (3 μg/ml) was administrated and the cell cycle was analyzed by PI staining followed by flow cytometry analysis. In addition, the expression of NF-κB (REL-A), CD44, c-MYC, and BMI-1 was evaluated via qPCR.

Results:

Assessment of cell viability revealed increased toxicity of AUR and ATO when used in combination. Our findings were confirmed by accumulation of cells in the sub G1 phase of the cell cycle and significant down-regulation of NF-κB (REL-A), CD44, c-MYC, and BMI-1.

Conclusion:

Obtained findings suggest that combinatorial use of AUR and ATO could be considered for designing novel chemotherapy regimens for ATLL.

Coumarins and Gastrointestinal Cancer: A New Therapeutic Option?

Cancers of the gastrointestinal (GI) tract are often life-threatening malignancies, which can be a severe burden to the health care system. Globally, the mortality rate from gastrointestinal tumors has been increasing due to the lack of adequate diagnostic, prognostic, and therapeutic measures to combat these tumors. Coumarin is a natural product with remarkable antitumor activity, and it is widely found in various natural plant sources. Researchers have explored coumarin and its related derivatives to investigate their antitumor activity, and the potential molecular mechanisms involved. These mechanisms include hormone antagonists, alkylating agents, inhibitors of angiogenesis, inhibitors of topoisomerase, inducers of apoptosis, agents with antimitotic activity, telomerase inhibitors, inhibitors of human carbonic anhydrase, as well as other potential mechanisms. Consequently, drug design and discovery scientists and medicinal chemists have collaborated to identify new coumarin-related agents in order to produce more effective antitumor drugs against GI cancers. Herein, we summarize the therapeutic effects of coumarin and its derivatives against GI cancer.

A Review of Auraptene as an Anticancer Agent

Auraptene is a bioactive monoterpene coumarin isolated from Citrus aurantium and Aegle marmelos that belong to the Rutaceae family. Auraptene can modulate intracellular signaling pathways that control cell growth, inflammation and apoptosis and can exert pharmacological properties such as anti-bacterial, anti-fungal, antileishmania and anti-oxidant activity. Auraptene had inhibitory and chemo-preventive effects on the proliferation, tumorigenesis and growth of several cancer cell lines through increase in the activity of glutathione S-transferase, formation of DNA adducts and reduction of the number of aberrant crypt foci. Auraptene exhibits anticancer effects via targeting different cell signaling pathways such as cytokines, genes modulating cellular proliferation, growth factors, transcription factors and apoptosis. The present review is a detailed survey of scientific researches on the cytotoxicity and anticancer activity of Auraptene on cancer cells and tumor bearing animals.

PPARγ transcription effect on naturally occurring O-prenyl cinnamaldehydes and cinnamyl alcohol derivatives

Background: PPARγ is known to be a key regulator of metabolism and storage of lipids and glucose and to be implicated in the pathology of severe syndromes like obesity, diabetes, atherosclerosis and cancer. Methods: As a continuation of the authors' studies on oxyprenylated secondary metabolites as effective PPARγ agonists, the authors describe herein the chemical synthesis of natural O-prenyl cinnamaldehydes and cinnamyl alcohols and preliminary data on their in vitro effects on PPARγ transcription. Results: Among the panel of eight compounds tested, three - namely, (2E)-3-(4-((E)3,7-dimethylocta-2,6-dienyloxy)-3-methoxyphenyl)acrylaldehyde, (2E)-3-(4-((E)3,7-dimethylocta-2,6-dienyloxy)-3-methoxyphenyl)prop-2-en-1-ol and boropinal A - exerted activity in a dose-dependent manner. Conclusion: O-prenyl cinnamaldehydes and cinnamyl alcohols have the potential to effectively interact with PPARγ receptor.

Comparative evaluation of the protective effects of oral administration of auraptene and umbelliprenin against CFA-induced chronic inflammation with polyarthritis in rats

This study aimed to evaluate the anti-inflammatory effect of Auraptene (AUR) and Umbelliprenin (UMB) in a rat model of rheumatoid arthritis (RA) induced by using complete Freund's adjuvant (CFA). Paw swelling of adjuvant arthritis rats measured at various times after CFA injection. Over 15 days of RA induction, mediator/cytokine-mediated processes involved in managing the regulation and resolving RA's inflammation were also quantified with ELISA. Histopathological changes were also assessed under a microscope 15 days after the CFA injection. AUR at all doses and UMB administration only at a 16 mM /kg administration dose significantly reduced CFA-induced paw edema level compared to the control group. UMB (64 and 32 mM) and AUR (64, 32, and 16 mM) could reduce the PGE2 (p < .0001-.01) and NO (p < .0001-.05) levels in the treatment groups compared to the negative control group. However, these compounds showed no significant effect on the TNF-α, IFN-γ, TGF-β, IL-4, and IL-10 levels than the control group (p > .05). Unlike indomethacin and prednisolone, treatment of rats with AUR (16, 32, and 64 mM/kg) and UMB (16 and 32 mM/kg) reduced the level of IL-2 (p < .0001). In all treatment groups, the serum level of IL-17 was significantly reduced compared to the CFA group (p < .001-0.05). We suggested AUR and UMB could diminish inflammation by reducing the serum level of IL-17 and could be considered a proper alternative in the treatment of IL-17 related inflammatory diseases such as rheumatoid arthritis. Given that AUR and UMB apply their anti-inflammatory effects by changing distinct cytokine release/inhibition patterns, their potential application in diverse inflammatory diseases seems different.

Antitumor effects of Auraptene in 4T1 tumor-bearing Balb/c mice

OBJECTIVES

Breast cancer is a common malignant tumor in women with limited treatment options and multiple side effects. Today, the anti-cancer properties of natural compounds have attracted widespread attention from researchers worldwide.

METHODS

In this study, we treated 4T1 tumor-bearing Balb/c mice with intraperitoneal injection of Auraptene, paraffin oil, and saline as two control groups. Body weight and tumor volume were measured before and after treatment. Hematoxylin and eosin (H & E) staining and immunohistochemistry of Ki-67 were used as markers of proliferation. In addition, ELISA assays were performed to assess serum IFN-γ and IL-4 levels.

RESULTS

There was no significant change in body weight in all animal groups before and after treatment. 10 days after the last treatment, Auraptene showed its anti-cancer effect, which was confirmed by the smaller tumor volume and H & E staining. In addition, Ki-67 expression levels were significantly reduced in tumor samples from the Auraptene-treated group compared to the paraffin oil and saline-treated groups. In addition, in tumor-bearing and normal mice receiving Auraptene treatment, IL-4 serum production levels were reduced, while serum levels of IFN-γ were significantly up-regulated in tumor-bearing mice after Auraptene treatment.

CONCLUSIONS

In the case of inhibition of tumor volume and Ki-67 proliferation markers, Auraptene can effectively inhibit tumor growth in breast cancer animal models. In addition, it might increases Th1 and CD8 + T cell responses after reducing IL-4 serum levels and IFN-γ upregulation, respectively. However, further research is needed to clarify its mechanism of action.

7-Isopentenyloxycoumarin: What Is New across the Last Decade

7-Isopentenyloxycoumarin is among the most widespread naturally occurring prenyloxy umbelliferone derivatives. This secondary metabolite of mixed biosynthetic origin has been typically isolated from plants belonging to several genera of the Rutaceae and Apiaceae families, comprising widely used medicinal plants and in general plants with beneficial effects on human welfare, as well as edible fruits and vegetables. Although known for quite a long time (more than 50 years), only in the last two decades has this natural compound been revealed to exert powerful and promising pharmacological properties, such as active cancer chemopreventive, antibacterial, antiprotozoal, antifungal, anti-inflammatory, neuroprotective, and antioxidant properties, among the activities best outlined in the recent literature. The aim of this comprehensive miniature review article is to detail the novel natural sources and the effects described during the last decade for 7-isopentenyloxycoumarin and what has been reported on the mechanisms of action underlying the observed biological activities of this oxyprenylated secondary metabolite. In view of the herein described data, suggestions on how to address future research on the abovementioned natural product and structurally related derivatives in the best ways according to the authors will be also provided.

pH-Responsive Fluorescence Enhanced Nanogel for Targeted Delivery of AUR and CDDP Against Breast Cancer

Introduction

Auraptene (AUR), a natural bioactive prenyloxy coumarin, is a highly pleiotropic molecule that can bind to the MT1 receptor and can effectively reduce the proliferation and migration of breast cancer cells. Cisplatin (CDDP), as the first synthetic platinum-based anticancer drug, is widely used in the clinic due to its definite mechanism and therapeutic effect on diverse tumors. However, both of AUR and CDDP exhibit some disadvantages when used alone, including poor solubility, low bioavailability, lack of selectivity and systemic toxicity when they are used singly.

Methods

Therefore, the biodegradable materials hyaluronic acid (HA) and β-cyclodextrin derivative (mono-(6-amino-mono-6-deoxy)-β-CD, CD) were employed as carriers to load AUR and CDDP to form nanogel (^CDDPHA-CD@AUR) capable of dual-targeted delivery and synergistic therapy for breast cancer and cell imaging.

Results

With the help of the CDDP-crosslinked CD-loaded structure, the newly synthesized nanogel exhibited excellent physiological stability and fluorescence effects. The release of AUR and CDDP was affected by the pH value, which was beneficial to the selective release in the tumor microenvironment. Cell experiments in vitro demonstrated that the nanogel could be selectively internalized by MCF-7 cells and exhibited low cytotoxicity to HK-2 cells. Antitumor experiments in vivo showed that the nanogel have better antitumor effects and lower systemic toxicity.

Conclusion

Based on these, the nanogel loaded with AUR and CDDP have the potential for targeted delivery against breast cancer.

Recycling of Almond By-Products for Intestinal Inflammation: Improvement of Physical-Chemical, Technological and Biological Characteristics of a Dried Almond Skins Extract

BACKGROUND

Almond skins are rich in bioactive compounds that undergo oxidation/degradation phenomena and are poorly soluble in water, reducing in vivo absorption and bioavailability, factors that influence the pharmacological activity of an active product. We developed a dried acetonic almond skins extract/cyclodextrin complex to improve extract solubility, dissolution rate and biological activity.

METHODS

A lyophilized acetonic almond skin extract was produced. To optimize complex formulation, phase solubility studies and complex characterization (absorption studies, differential scanning calorimetry (DSC), morphology, solubility studies) were performed. To evaluate a possible use in healthy products, tumor necrosis factor-α levels and reactive oxygen species release, as well as cicloxygenase-2 and inducible nitric oxide synthase expression in intestinal epithelial cells, were also evaluated.

RESULTS

Phase solubility studies showed a Bs-type profile. A 1:1 dried acetonic almond skins extract/cyclodextrin ratio was able to improve extract water solubility and dissolution rate (100% in 45 min). The UV-Vis spectra of complex revealed a hypsochromic and hyperchromic effect, probably due to a partial inclusion of extract in cyclodextrin cavity through weak bonds, confirmed by DSC and morphology studies. The technological improvement in the extract characteristics also led to better biological activity. In fact, the complex effectively reduces tumor necrosis factor-α levels with respect to the pure extract and significantly inhibits the reactive oxygen species release, even if only at the lower concentration of 5 μg/mL.

CONCLUSION

The complex was able to overcome solubility problems and could be used in inflammatory disease.

Anti-Migratory Effects of 4'-Geranyloxyferulic Acid on LPS-Stimulated U937 and HCT116 Cells via MMP-9 Down-Regulation: Involvement of ROS/ERK Signaling Pathway

Matrix metalloproteinases (MMPs) play a crucial role in tumor angiogenesis, and metastasis. 4'-geranyloxyferulic acid (GOFA) has anti-tumor and anti-inflammatory proprieties. Herein, we aimed to determine whether this compound affects cell survival, invasion, and migration through reactive oxygen species (ROS)-mediated MMPs activation of extracellular signal-regulated kinases (ERKs) and p38 signaling in lymphocytic histiocytoma (U937) and colorectal cancer (HCT116) cells. We observed that lipopolysaccharide (LPS) stimulated U937 and HCT116 cells presented abnormal cell proliferation and increased metalloproteinase (MMP-9) activity and expression. Non-cytotoxic doses of GOFA blunted matrix invasive potential by reducing LPS-induced MMP-9 expression and cell migration via inhibiting ROS/ ERK pathway. GOFA also attenuated apoptosis and cell senescence. Our findings indicate that GOFA, inhibiting cancer cell proliferation and migration, could be therapeutically beneficial to prevent tumor metastasis.

Dietary Fucoxanthin Induces Anoikis in Colorectal Adenocarcinoma by Suppressing Integrin Signaling in a Murine Colorectal Cancer Model

Fucoxanthin (Fx), abundantly contained in edible brown algae, is a carotenoid with strong anti-cancer potential. Anoikis is an anchor-dependent apoptosis particularly related to integrin signaling, and a target for cancer preventive strategies. We recently demonstrated that Fx prevented colon cancer in azoxymethane-dextrane sodium sulfate (AOM/DSS) carcinogenic model mice, and that it increased anoikis-like integrin β1^low/-/cleaved caspase-3^high cells in colonic mucosal crypts. However, an induction mechanism of anoikis by Fx in adenocarcinoma tissue remains unresolved. Thus, we investigated anoikis in colonic adenocarcinoma in AOM/DSS mice. Fx administration (30 mg/kg body weight) significantly suppressed the incidence and multiplicity of colonic adenocarcinoma in AOM/DSS mice. A number of anoikis-like integrin β1^low/-/cleaved caspase-3^high cells in colonic adenocarcinoma and mucosal crypts were significantly increased, 8.3- and 3.5-fold in the Fx group compared with those of the control group, respectively. The results indicated the increase of anoikis-like cells occurred more strongly in colonic adenocarcinoma than in colonic mucosal crypts. In addition, integrin β1 expression, and pFAK (Tyr³⁹⁷) and pPaxillin (Tyr³¹) activation in mucosal tissue decreased 0.7-, 0.5- and 0.6-fold by Fx administration, respectively. The results suggest that Fx induces anoikis in colonic adenocarcinoma developed by AOM/DSS treatment through attenuation of integrin signaling.

A review of the pharmacological and therapeutic effects of auraptene

There is a growing awareness in herbal medications as they are usually safe and devoid of significant adverse effects. Auraptene is a natural bioactive monoterpene coumarin ether and is consumed all over the world. There is growing evidence of the therapeutic benefits of auraptene. Auraptene, also known as auraptene and 7-geranyloxycoumarin, is a bioactive monoterpene coumarin from Rutaceae family, which is isolated from Citrus aurantium (Seville orange) and Aegle marmelos (bael fruit). Auraptene is a highly pleiotropic molecule, which can modulate intracellular signaling pathways that control inflammation, cell growth, and apoptosis. It has a potential therapeutic role in the prevention and treatment of various diseases due to its anti-inflammatory and antioxidant activities as well as its excellent safety profile. In the present article, various pharmacological and therapeutic effects of auraptene were reviewed. Different online databases using keywords such as auraptene, therapeutic effects and pharmacological effects were searched until the end of September 2018, for this purpose. Auraptene has been suggested to be effective in the treatment of a broad range of disorders including inflammatory disorders, dysentery, wounds, scars, keloids, and pain. In addition, different studies have demonstrated that auraptene possesses numerous pharmacological properties including anti-inflammatory, anti-oxidative, anti-diabetic, anti-hypertensive and anti-cancer as well as neuroprotective effects. The present review provides a detailed survey of scientific researches regarding pharmacological properties and therapeutic effects of auraptene.

Poly(3-hydroxi-butyrate-co-3-hydroxy-valerate) (PHB-HV) microparticles loaded with holmium acetylacetonate as potential contrast agents for magnetic resonance images

Introduction

Biodegradable polymers that contain radioactive isotopes such as Holmium 166 have potential applications as beta particle emitters in tumor tissues. Also, Ho(III) is paramagnetic, which makes it suitable as a contrast agent for magnetic resonance (MR) images.

Methods

Holmium acetylacetonate (Ho(acac)₃) loaded poly(3-hydroxy-butyrate-co-3-hydroxy-valerate) microspheres, with 5% or 8% of 3-hydroxy-valerate (HV), were prepared by emulsification/evaporation process within 20–53 μm size. Microspheres characterization was done using scanning electron microscopy, energy-dispersive X-ray, and infrared spectroscopies. The release of holmium(III) in sodium phosphate buffer (pH 7.4) was followed for 9 days with inductively coupled plasma. Finally, T₂ and T₂* magnetic resonance images (MRI) were acquired and compared with the MRI of the inclusion complex of holmium acetylacetonate in some β-cyclodextrins.

Results

Holmium acetylacetonate loading, evaluated by thermogravimetry, was up to 20 times higher for copolymer with 5% of HV. It was shown that microspheres loaded with Ho(acac)₃ exhibited an accumulation of Ho(III) on their surfaces but were stable over time, as no expressive release of holmium(III) was detected in 9-day exposition to sodium phosphate buffer. Holmium acetylacetonate in both microspheres or inclusion complexes was very efficient in obtaining T₂ and T₂* weighted images in magnetic resonance, thus, might be used as contrast agents.

Conclusion

This is the first description of the use of inclusion complexes of holmium acetylacetonate in biodegradable polymers as contrast agents. New investigations are underway to evaluate the resistance of PHB-HV polymer microparticles to nuclear activation to assess their potential for use as radiopharmaceuticals for the treatment of liver cancer.

Auraptene-induced cytotoxicity mechanisms in human malignant glioblastoma (U87) cells: role of reactive oxygen species (ROS)

Glioblastoma multiforme (GBM), like the devastating type of astrocytic tumors, is one of the most challenging cancers to treat owing to its aggressive nature. Auraptene, as a prenyloxy coumarin from citrus species, represents antioxidant and antitumor activities; however, the underlying antitumor mechanisms of auraptene against GBM remain unclear. The present study aimed to evaluate the cytotoxic and apoptogenic effects of auraptene, as a promising natural product, and the possible signaling pathways affected in human malignant GBM (U87) cells. Reactive oxygen species (ROS) production significantly decreased in the first 2, and 6 hours after treatment with auraptene however, ROS levels increased in other incubation times (8 and 24 hours), dramatically. N-acetyl-cysteine (NAC) markedly attenuated auraptene-induced ROS production, and consequently reversed auraptene-induced cytotoxicity in 8 and 24 hours after treatment, as well. Induction of apoptosis occurred in the first 24- and 48-hours concentration-dependently. The qRT-PCR showed an up-regulation in p21, CXCL3, and a down-regulation in Cyclin D1 genes expression. Western blot analysis confirmed the up-regulation of the Bax/Bcl-2 ratio protein levels concentration-dependently. Hence, this study collectively revealed that the increase in ROS level is at least one of the mechanisms associated with auraptene-induced GBM cell toxicity as well as the induction of apoptosis through Bax/Bcl-2 modulation and genes expression involved that contribute to the cytotoxicity of auraptene in U87 cells. So, auraptene might be utilized as a potential novel anti-GBM agent after further studies.

Modulation of CAT-2B-Mediated l-Arginine Uptake and Nitric Oxide Biosynthesis in HCT116 Cell Line Through Biological Activity of 4'-Geranyloxyferulic Acid Extract from Quinoa Seeds

Chenopodium quinoa Wild is a “pseudocereal” grain which attracts a lot of attention in the scientific community as it has a positive effect on health. Here, we investigate the presence of biologically active O-prenylated phenylpropanoids in the ethanol extract of commercially available quinoa seeds. We claim that 4′-Geranyloxyferulic acid (GOFA) was the only phytochemical product found that belongs to quinoa’s group secondary metabolites. We studied the changes in the oxidative and inflammatory status of the cellular environment in HCT 116 cell line processed with quinoa extract and its component GOFA; the implementation was done through the analysis of the antioxidant enzymes (SOD and CAT), the pro-inflammatory components (iNOS, IL-6 and TNF-α), and the products of intermediary metabolism (ONOO⁻, O₂⁻). Moreover, the l-arginine uptake was proposed as a target of the tested compounds. We demonstrated that the GOFA, through a decrease of the CAT-2B expression, leads to a reduction of the l-arginine uptake, downregulating the harmful iNOS and restoring the altered redox state. These results propose a new molecular target involved in the reduction of the critical inflammatory process responsible for the cancer progression.

Biomolecular Targets of Oxyprenylated Phenylpropanoids and Polyketides

Oxyprenylated secondary metabolites (e.g. phenylpropanoids and polyketides) represent a rare class of natural compounds. Over the past two decades, this group of phytochemicals has become a topic of intense research activity by several teams worldwide due to their in vitro and in vivo pharmacological activities, and to their great therapeutic and nutraceutical potential for the chemoprevention of acute and chronic diseases affecting humans. Such investigations have provided evidence that oxyprenylated secondary metabolites are able to interact with several biological targets at different levels accounting for their observed anticarcinogenic, anti-inflammatory, neuroprotective, immunomodulatory, antihypertensive, and metabolic effects. The aim of the present contribution is to provide a detailed survey of the so far reported data on the capacities of selected oxyprenylated phenylpropanoids and polyketides to trigger receptors, enzymes, and other types of cellular factors for which they exhibit a high degree of affinity and therefore evoke specific responses. With respect to the rather small amounts of these compounds available from natural sources, their chemical synthesis is also highlighted.

Triticum aestivum Sprouts Extract Inhibits Azoymethane (AOM)/Dextran Sodium Sulfate (DSS)-Induced Colon Carcinogenesis in Mice

Chronic intestinal inflammation is critical risk factor of colorectal cancer. Triticum aestivum sprouts have been reported to provide a number of health benefits and used as a dietary supplement. In this study, the authors investigated the regulatory effects of T. aestivum sprouts ethanol extract (TAEE) on experimental colorectal carcinogenesis in an azoxymethane (AOM)/dextran sulfate sodium (DSS)-induced mouse model. Oral administration of TAEE significantly attenuated crypt destruction and tumor formation in AOM/DSS-treated mice. Levels of inflammatory mediators involved in colorectal carcinogenesis, that is, tumor necrosis factor-α, interkeukin (IL)-1β, IL-6, cyclooxygenase-2, and inducible nitric oxide synthase, were lower in the colons of 200 mg/kg TAEE-treated mice than in AOM/DSS controls (p < 0.05). Immunohistochemical staining showed that levels of nuclear factor-kappa B p65 and β-catenin were attenuated by TAEE in the colon tissues of AOM/DSS-treated mice. Furthermore, levels of β-catenin-related genes (cyclin D1 and c-Myc), which are known to contribute to cell cycle regulation, were decreased in the colon tissues of TAEE-treated mice versus AOM/DSS controls (p < 0.01). These results showed TAEE inhibited colon inflammation and neoplasm formation caused by AOM/DSS treatment, suggesting that TAEE could be useful for the prevention and treatment of colitis-associated colon cancer.

Structure-Based Classification and Anti-Cancer Effects of Plant Metabolites

A variety of malignant cancers affect the global human population. Although a wide variety of approaches to cancer treatment have been studied and used clinically (surgery, radiotherapy, chemotherapy, and immunotherapy), the toxic side effects of cancer therapies have a negative impact on patients and impede progress in conquering cancer. Plant metabolites are emerging as new leads for anti-cancer drug development. This review summarizes these plant metabolites with regard to their structures and the types of cancer against which they show activity, organized by the organ or tissues in which each cancer forms. This information will be helpful for understanding the current state of knowledge of the anti-cancer effects of various plant metabolites against major types of cancer for the further development of novel anti-cancer drugs.

Safety evaluation of auraptene in rats in acute and subacute toxicity studies

Auraptene (AUR) is a natural, bioactive, monoterpene coumarin ether. It has anti-inflammatory, anti-carcinogenic, anti-bacterial, neuroprotective, and hepatoprotective properties. The aim of the present study was to assess the acute and subacute toxicity of oral administration of AUR in rats by evaluating clinical signs, haematology, biochemical factors, pathological changes and immune-toxicity. Acute administration of AUR in doses of 125, 250, 500, 1000 and 2000 mg/kg body weight had no mortality or clinical signs in a period of two days. To evaluate subacute toxicity, AUR was administrated for 28 days by oral gavage in doses of 125 and 250 mg/kg. There were significant differences in the haematological and biochemical data of the treated and untreated groups. However, almost all haematological differences were within normal reference ranges. Subacute administration of AUR showed no toxic histopathological effects on organ tissue. Evaluation of immune-toxicity also revealed no significant differences between treatment and untreated groups.

Efficacy of hyperthermia in human colon adenocarcinoma cells is improved by auraptene

Colon adenocarcinoma is one of the most common cancers worldwide, and resistance to current therapeutic modalities is a serious drawback in its treatment. Auraptene is a natural coumarin with considerable anticancer effects. The goal of this study was to introduce a novel combinatorial approach for treatment against colon adenocarcinoma cells. To do so, HT29 cells were pretreated with nontoxic auraptene and then hyperthermia was induced. Afterwards, the viability of the cells was assessed, changes induced in the cell cycle were analyzed, and the expression patterns of candidate genes were studied. Results from the MTT assay demonstrated significant (p < 0.01) decreases in cell viability when 20 μg/mL auraptene was used for 72 h, heat shock was induced, and cells were allowed to recover for 24 h. Flow cytometry analysis also indicated considerable changes in the distribution of cells between the sub-G₁/G₁ and G₂/M phases of cell cycle after the combinatorial treatment. Real-time RT-PCR studies revealed significant (p < 0.01) up-regulation of P21 in the cells pretreated with auraptene after heat shock, whereas no significant change was observed in HSP27 expression. Our findings not only indicate, for the first time, that the efficacy of hyperthermia was improved by auraptene pretreatment, but also suggest that this coumarin could be used in the future to achieve more effective therapeutic outcomes.

Synergy between Auraptene, Ionizing Radiation, and Anticancer Drugs in Colon Adenocarcinoma Cells

Colorectal cancer is a growing health concern with increasing mortality rates, and resistance to anticancer drugs and radiotherapy is a serious drawback in its treatment. Auraptene is a natural prenyloxycoumarin with valuable anticancer effects. The aim of current study was to determine the synergy between auraptene, ionizing radiation, and chemotherapeutic drugs in colon adenocarcinoma cells for the first time. To do so, HT29 cells were treated with combination of auraptene + cisplatin, + doxorubicin, or + vincristine. Furthermore, cells were pretreated with nontoxic auraptene and then exposed to various doses of X-radiation. Assessment of cell viability not only indicated significant (p < 0.05) synergic effects of auraptene and anticancer agents, also revealed more significant (p < 0.01) increase in the toxicity of applied radiations in auraptene pretreated cells. Interesting synergy between auraptene and radiotherapy was then confirmed by morphological alterations, DAPI staining, and flow cytometric analysis of the cell cycle. Moreover, real-time reverse transcription polymerase chain reaction analysis indicated significant (p < 0.01) overexpression of p21, but not GATA6, in auraptene pretreated cells after radiotherapy, and also significant (p < 0.01) down regulation of CD44 and ALDH1 by auraptene. According to present results, auraptene could be considered as an effective natural coumarin to improve the outcome of current chemoradiotherapy options. Copyright © 2017 John Wiley & Sons, Ltd.

Chemopreventive Strategies for Inflammation-Related Carcinogenesis: Current Status and Future Direction

A sustained and chronically-inflamed environment is characterized by the presence of heterogeneous inflammatory cellular components, including neutrophils, macrophages, lymphocytes and fibroblasts. These infiltrated cells produce growth stimulating mediators (inflammatory cytokines and growth factors), chemotactic factors (chemokines) and genotoxic substances (reactive oxygen species and nitrogen oxide) and induce DNA damage and methylation. Therefore, chronic inflammation serves as an intrinsic niche for carcinogenesis and tumor progression. In this article, we summarize the up-to-date findings regarding definitive/possible causes and mechanisms of inflammation-related carcinogenesis derived from experimental and clinical studies. We also propose 10 strategies, as well as candidate agents for the prevention of inflammation-related carcinogenesis.

Quantitative profiling of 4'-geranyloxyferulic acid and its conjugate with l-nitroarginine methyl ester in mononuclear cells by high-performance liquid chromatography with fluorescence detection

Oxyprenylated natural products were shown to exert in vitro and in vivo remarkable anti-cancer and anti-inflammatory effects. This paper describes a rapid, selective, and sensitive HPLC method with fluorescence detection for determination of 4'-geranyloxyferulic acid (GOFA) and its conjugate with l-nitroarginine methyl ester (GOFA-L-NAME) in mononuclear cells. Analytes were extracted from cells using methanol and eluted on a GraceSmart RP₁₈ analytical column (250×4.6mm i.d., 5μm particle size) kept at 25°C. A mixture of formic acid 1% in water (A) and methanol (B) were used as mobile phase, at a flow-rate of 1.2mL/min in gradient elution. A fluorescence detector (excitation/emission wavelength of 319/398nm for GOFA and GOFA-L-NAME), was used for the two analytes. Calibration curves of GOFA and GOFA-L-NAME were linear over the concentration range of 1.0-50μg/mL, with correlation coefficients (r²)≥0.9995. Intra- and inter-assay precision do not exceed 6.8%. The accuracy was from 94% to 105% for quality control samples (2.0, 25.0 and 40μg/mL). The mean (RSD%) extraction recoveries (n=5) for GOFA and GOFA-L-NAME from spiked cells at 2.0, 25.0 and 40.0μg/mL were 92.4±1.5%, 94.7±0.9% and 93.8±1.1%, for GOFA and 95.3±1.2%, 94.8±1.0% and 93.9±1.3%, for GOFA-L-NAME. The limits of detection and quantification were 0.3μg/mL and 1.0μg/mL for GOFA and GOFA-L-NAME. This method was successfully applied to measure GOFA and GOFA-L-NAME concentrations in a mononuclear cells.

Auraptene and Other Prenyloxyphenylpropanoids Suppress Microglial Activation and Dopaminergic Neuronal Cell Death in a Lipopolysaccharide-Induced Model of Parkinson's Disease

In patients with Parkinson’s disease (PD), hyperactivated inflammation in the brain, particularly microglial hyperactivation in the substantia nigra (SN), is reported to be one of the triggers for the delayed loss of dopaminergic neurons and sequential motor functional impairments. We previously reported that (1) auraptene (AUR), a natural prenyloxycoumain, suppressed inflammatory responses including the hyperactivation of microglia in the ischemic brain and inflamed brain, thereby inhibiting neuronal cell death; (2) 7-isopentenyloxycoumarin (7-IP), another natural prenyloxycoumain, exerted anti-inflammatory and neuroprotective effects against excitotoxicity; and (3) 4′-geranyloxyferulic acid (GOFA), a natural prenyloxycinnamic acid, also exerted anti-inflammatory effects. In the present study, using an intranigral lipopolysaccharide (LPS)-induced PD-like mouse model, we investigated whether AUR, 7-IP, and GOFA suppress microglial activation and protect against dopaminergic neuronal cell death in the SN. We successfully showed that these prenyloxyphenylpropanoids exhibited these prospective abilities, suggesting the potential of these compounds as neuroprotective agents for patients with PD.

Auraptene Attenuates Malignant Properties of Esophageal Stem-Like Cancer Cells

The high incidence of esophageal squamous cell carcinoma has been reported in selected ethnic populations including North of Iran. Low survival rate of esophageal carcinoma is partially due to the presence of stem-like cancer cells with chemotherapy resistance. In the current study, we aimed to determine the effects of auraptene, an interesting dietary coumarin with various biological activities, on malignant properties of stem-like esophageal squamous cell carcinoma, in terms of sensitivity to anticancer drugs and expression of specific markers. To do so, the half maximal inhibitory concentration values of auraptene, cisplatin, paclitaxel, and 5-fluorouracil were determined on esophageal carcinoma cells (KYSE30 cell line). After administrating combinatorial treatments, including nontoxic concentrations of auraptene + cisplatin, paclitaxel, or 5-fluorouracil, sensitivity of cells to chemical drugs and also induced apoptosis were assessed. In addition, quantitative real-time polymerase chain reaction was used to study changes in the expression of tumor suppressor proteins 53 and 21 ( P53 and P21), cluster of differentiation 44 ( CD44), and B cell-specific Moloney murine leukemia virus integration site 1 ( BMI-1) upon treatments. Results of thiazolyl blue assay revealed that auraptene significantly ( P < .05) increased toxicity of cisplatin, paclitaxel, and 5-fluorouracil in KYSE30 cells, specifically 72 hours after treatment. Conducting an apoptosis assay using flow cytometry also confirmed the synergic effects of auraptene. Results of quantitative real-time polymerase chain reaction revealed significant ( P < .05) upregulation of P53 and P21 upon combinatorial treatments and also downregulation of CD44 and BMI-1 after auraptene administration. Current study provided evidence, for the first time, that auraptene attenuates the properties of esophageal stem-like cancer cells through enhancing sensitivity to chemical agents and reducing the expression of CD44 and BMI-1 markers.

Cimetidine and Clobenpropit Attenuate Inflammation-Associated Colorectal Carcinogenesis in Male ICR Mice

Histamine and histamine receptors (Hrhs) have been identified as critical molecules during inflammation and carcinogenesis. This study was conducted to determine the effects of Hrh1-Hrh3 antagonists on inflammation-associated colorectal carcinogenesis. Male ICR mice were treated with azoxymethane (AOM, 10 mg/kg bw, i.p.) and 1.5% dextran sodium sulfate (DSS, drinking water for 7 days) to induce colorectal carcinogenesis. The mice were then fed diets containing test chemical (500 ppm terfenadine, 500 ppm cimetidine or 10 ppm clobenpropit) for 15 weeks. At week 18, feeding with the diets containing cimetidine (Hrh2 antagonist) and clobenpropit (Hrh3 antagonist/inverse agonist) significantly lowered the multiplicity of colonic adenocarcinoma. Terfenadine (Hrh1 antagonist) did not affect AOM-DSS-induced colorectal carcinogenesis. Adenocarcinoma cells immunohistochemically expressed Hrh1, Hrh2, Hrh3 and Hrh4 with varied intensities. Because clobenpropit is also known to be a Hrh4 receptor agonist, Hrh2, Hrh3 and Hrh4 may be involved in inflammation-related colorectal carcinogenesis. Additional data, including the mRNA expression of pro-inflammatory cytokines and inducible inflammatory enzymes in the colonic mucosa, are also presented.

Auraptene and Its Role in Chronic Diseases

Auraptene (7-geranyloxycoumarin) is the best known and most abundant prenyloxycoumarin present in nature. It is synthesized by various plant species, mainly those of the Rutaceae and Umbeliferae (Apiaceae) families, comprising many edible fruits and vegetables such as lemons, grapefruit and orange. Auraptene has shown a remarkable effect in the prevention of degenerative diseases, in particular it has been reported to be one the most promising known natural chemopreventive agents against several types of cancer. The aim of this chapter is to review the effects of auraptene in the prevention and treatment of different chronic diseases.

STAT3 and sphingosine-1-phosphate in inflammation-associated colorectal cancer

Accumulated evidences have demonstrated that signal transducer and activator of transcription 3 (STAT3) is a critical link between inflammation and cancer. Multiple studies have indicated that persistent activation of STAT3 in epithelial/tumor cells in inflammation-associated colorectal cancer (CRC) is associated with sphingosine-1-phosphate (S1P) receptor signaling. In inflammatory response whereby interleukin (IL)-6 production is abundant, STAT3-mediated pathways were found to promote the activation of sphingosine kinases (SphK1 and SphK2) leading to the production of S1P. Reciprocally, S1P encourages the activation of STAT3 through a positive autocrine-loop signaling. The crosstalk between IL-6, STAT3 and sphingolipid regulated pathways may play an essential role in tumorigenesis and tumor progression in inflamed intestines. Therapeutics targeting both STAT3 and sphingolipid are therefore likely to contribute novel and more effective therapeutic strategies against inflammation-associated CRC.

A newly synthesized compound, 4'-geranyloxyferulic acid-N(omega)-nitro-L-arginine methyl ester suppresses inflammation-associated colorectal carcinogenesis in male mice

We previously reported the cancer chemopreventive activity of 4'-geranyloxyferulic acid (GOFA, Miyamoto et al., Nutr Cancer 2008; 60:675-84) and a β-cyclodextrin inclusion compound of GOFA (Tanaka et al., Int J Cancer 2010; 126:830-40) in colitis-related colorectal carcinogenesis. In our study, the chemopreventive effects of a newly synthesized GOFA-containing compound, GOFA-N(omega)-nitro-L-arginine methyl ester (L-NAME), which inhibits inducible nitric oxide (iNOS) and cyclooxygenase-2 (COX) enzymes, were investigated using a colitis-associated mouse colorectal carcinogenesis model with azoxymethane (AOM) and dextran sodium sulfate (DSS). The dietary administration of GOFA-L-NAME after the AOM and DSS treatments significantly reduced the multiplicity of adenocarcinomas (inhibition rates: 100 ppm, 84%, p < 0.001; 500 ppm, 94%, p < 0.001) compared with the AOM + DSS group. Dietary GOFA-L-NAME significantly decreased the proliferation (p < 0.001) and increased the apoptosis (p < 0.001) of colonic adenocarcinoma cells. A subsequent short-term experiment revealed that dietary GOFA-L-NAME decreased the mRNA expression of inflammatory enzymes, such as iNOS and COX-2, and proinflammatory cytokines, such as tumor necrosis factor-α, interleukin (IL)-1β, IL-6 and macrophage inflammatory protein (MIP)-2 in the colonic mucosa of mice that received 1.5% DSS in their drinking water for 7 days. Our findings indicate that GOFA-L-NAME is able to inhibit colitis-associated colon carcinogenesis by modulating inflammation, proliferation, apoptosis and the expression of proinflammatory cytokines in mice.

Phytochemistry and pharmacognosy of the genus Acronychia

The genus Acronychia (Rutaceae) comprise 44 species, most of which are represented by shrubs and small trees, distributed in a wide geographical area of South-Eastern Asia comprising China, India, Malaysia, Indonesia, Australia, and the islands of the western Pacific Ocean. Most of the species of the genus Acronychia have been used for centuries as natural remedies in the ethnomedical traditions of indigenous populations as anti-microbial, anti-fungal, anti-spasmodic, stomachic, anti-pyretic, and anti-haemorragic agent. Moreover fruits and aerial parts are used as food in salads and condiments, while the essential oil obtained from flowers and leaves has been employed in cosmetics production. Phytochemicals isolated from Acronychia spp. include acetophenones, quinoline and acridone alkaloids, flavonoids, cinnamic acids, lignans, coumarins, steroids, and triterpenes. The reported biological activities of the above mentioned natural compounds refer to anti-plasmodial, anti-cancer, anti-oxidant, anti-inflammatory, anti-fungal, and neuroprotective effects. The aim of this review is to examine in detail from a phytochemical and pharmacologically point of view what is reported in the current literature about the properties of phytopreparations or individual active principles obtained from plants belonging to the Acronychia genus.

3-aroylmethylene-2,3,6,7-tetrahydro-1H-pyrazino[2,1-a]isoquinolin-4(11bH)-ones as potent Nrf2/ARE inducers in human cancer cells and AOM-DSS treated mice

Nrf2-mediated activation of ARE regulates expression of cytoprotective enzymes against oxidative stress, inflammation, and carcinogenesis. We have discovered a novel structure (1) as an ARE inducer via luciferase reporter assay to screen the in-house database of our laboratory. The potency of 1 was evaluated by the expression of NQO-1, HO-1, and nuclear translocation of Nrf2 in HCT116 cells. In vivo potency of 1 was studied using AOM-DSS models, showing that the development of colorectal adenomas was significantly inhibited. Administration with 1 lowered the expression of IL-6, IL-1β, and promoted Nrf2 nuclear translocation. These results indicated that 1 is a potent Nrf2/ARE activator, both in vitro and in vivo. Forty-one derivatives were synthesized for SAR study, and a more potent compound 17 was identified. To our knowledge, this is a potent ARE activator. Besides, its novel structure makes it promising for further optimization.

Evaluation of tumor suppressor gene expressions and aberrant methylation in the colon of cancer-induced rats: a pilot study

Altered expression and methylation pattern of tumor suppressor and DNA repair genes, in particular involved in mismatch repair (MMR) pathway, frequently occur in primary colorectal (CRC) tumors. However, little is known about (epi)genetic changes of these genes in precancerous and early stages of CRC. The aim of this pilot study was to analyze expression profile and promoter methylation status of important tumor suppressor and DNA repair genes in the early stages of experimentally induced colorectal carcinogenesis. Rats were treated with azoxymethane (AOM), dextran sodium sulphate (DSS) or with their combination, and sacrificed 1 or 4 months post-treatment period. The down-regulation of Apc expression in left colon, detectable in animals treated with DSS-AOM and sacrificed 1 month after the end of treatment, represents most early marker of the experimental colorectal carcinogenesis. Significantly reduced gene expressions were also found in 5 out of 7 studied MMR genes (Mlh1, Mlh3, Msh3 Pms1, Pms2), regarding the sequential administration of DSS-AOM at 4 months since the treatment. Strong down-regulation was also discovered for Apc, Apex1, Mgmt and TP53. Tumors developed in rectum-sigmoid region displayed significantly lower Apc and Pms2 expressions. The decreased expression of studied genes was not in any case associated with aberrant methylation of promoter region. Present data suggest that down-regulation of Apc and MMR genes are prerequisite for the development of CRC. In this study we addressed for the first time early functional alterations of tumor suppressor genes with underlying epigenetic mechanisms in experimentally induced CRC in rats.

Quantitative evaluation of auraptene and umbelliferone, chemopreventive coumarins in citrus fruits, by HPLC-UV-FL-MS

An analytical strategy, based on the development of two HPLC methods with spectrophotometric (UV), spectrofluorometric (FL), and mass spectrometric (MS) detection, has been developed to investigate the presence of and to quantitate two important chemopreventive coumarins, auraptene and umbelliferone, in foodstuffs. The analytes were determined in fruits, and fruit parts, of plants belonging to the Citrus , Poncirus , and Fortunella genera, to test their nutraceutical potential. The method validation has been carried out according to international guidelines, with good results in terms of precision (RSD < 6.9%) and extraction yields (>91%). Application to the quantitative analysis of auraptene and umbelliferone in several kinds of citrus fruits was successful, providing reliable and consistent data. Exploiting three different kinds of detection, the analytical methodology proposed herein has been demonstrated to be sound but versatile, as well as reliable. Performances and results were compared and always found in good agreement among themselves. Thus, this approach is suitable for the identification and simultaneous quantitation of auraptene and umbelliferone in citrus fruits, with the aim of evaluating their nutraceutical potential.

Preclinical cancer chemoprevention studies using animal model of inflammation-associated colorectal carcinogenesis

Inflammation is involved in all stages of carcinogenesis. Inflammatory bowel disease, such as ulcerative colitis and Crohn’s disease is a longstanding inflammatory disease of intestine with increased risk for colorectal cancer (CRC). Several molecular events involved in chronic inflammatory process are reported to contribute to multi-step carcinogenesis of CRC in the inflamed colon. They include over-production of free radicals, reactive oxygen and nitrogen species, up-regulation of inflammatory enzymes in arachidonic acid biosynthesis pathway, up-regulation of certain cytokines, and intestinal immune system dysfunction. In this article, firstly I briefly introduce our experimental animal models where colorectal neoplasms rapidly develop in the inflamed colorectum. Secondary, data on preclinical cancer chemoprevention studies of inflammation-associated colon carcinogenesis by morin, bezafibrate, and valproic acid, using this novel inflammation-related colorectal carcinogenesis model is described.

Auraptene and its effects on the re-emergence of colon cancer stem cells

Recent studies indicate that auraptene (7-geranyloxycoumarin, AUR), a geranyloxycoumarin extracted from fruits of edible plants belonging to the Rutaceae family, may represent a novel lead compound for dietary colon cancer chemoprevention in rodents. As a continuation of studies aimed to better depict the pharmacological effects and mechanism of action of the title natural compound, the current investigation was undertaken to determine whether AUR would be able to prevent the growth and sphere (surrogate tumors) formation of FOLFOX-resistant colon cancer cells that are highly enriched in cancer stem cells (CSCs). Our results demonstrate that AUR at a concentration of 10 μM was able to inhibit the growth and formation of colonospheres of FOLFOX-resistant colon cancer HT-29 cells in vitro. The corresponding parental cells were also similarly affected by AUR at the same concentration level. The reduction in the growth and colonospheres formation in FOLFOX-resistant HT-29 was also associated with a concomitant decrease in phospho-epidermal growth factor receptor. These findings suggest that AUR could prevent the re-emergence of CSCs.

Glucans from the edible mushroom Pleurotus pulmonarius inhibit colitis-associated colon carcinogenesis in mice

BACKGROUND

We have recently demonstrated that polysaccharides from fruiting body extract (FBE) or mycelia extract (ME) of the edible mushroom Pleurotus pulmonarius exert antiproliferative effects in intestinal cells and an anti-inflammatory effect in a dextran sulfate sodium (DSS) mouse model of acute colitis. The aim of this study was to assess the role of fungal FBE and ME in colon carcinogenesis.

METHODS

In vitro, human colorectal cancer cells were treated with FBE and ME and analyzed for inflammation response, for markers of apoptosis, and for cell-cycle progression. In vivo, FBE and ME were tested in a mouse model of colitis-associated colorectal carcinogenesis induced by cyclic treatments with DSS and azoxymethane. Treated mice were fed a daily diet containing 2 or 20 mg FBE or ME per mouse for 80 days.

RESULTS

In vitro, FBE and ME induced apoptosis in a dose-responsive manner and modulated the expression of Bcl-2, Bax, and cytochrome c, and blocked tumor necrosis factor (TNF)-α-induced inhibitor of nuclear factor (NF) (Iκ)-Bα degradation and NF-κB nuclear translocation. In vivo, dietary administration of FBE and ME significantly reduced the formation of aberrant crypt foci, which precedes colorectal cancer, and of microadenomas. The treatments significantly lowered the expression of proliferating cell nuclear antigen and increased the number of cells undergoing apoptosis in the colon. Additionally, FBE and ME inhibited the expression of the proinflammatory cytokine TNF-α in colonic tissue.

CONCLUSIONS

We conclude that P. pulmonarius FBE and ME inhibit colitis-associated colon carcinogenesis induced in mice through the modulation of cell proliferation, induction of apoptosis, and inhibition of inflammation.

Suppressive effect of zinc on the formation of colonic preneoplastic lesions in the mouse fed high levels of dietary iron

We investigated the effect of zinc on the formation of colonic aberrant crypt foci induced by azoxymethane (AOM) followed by dextran sodium sulfate (DSS) in mice with high iron diet (HFe; 450 ppm iron). Sixweek old ICR mice were fed on high iron diets with combination of three different levels of zinc in diets, low-zinc (LZn; 0.01 ppm), medium-zinc (MZn; 0.1 ppm), and high-zinc (HZn; 1 ppm) for 12 weeks. Animals were received weekly intraperitoneal injections of AOM (10 mg/kg B.W. in saline) for 3 weeks followed by 2% DSS (molecular weight 36,000~50,000) in the drinking water for a week. To confirm the iron storage in the body, the hepatic iron concentration has been determine chemically and compared with histological assessment visualized by Prussian blue reaction. Aberrant crypt (AC) and aberrant crypt foci (ACF) were analyzed in the colonic mucosa of mouse fed high dietary iron. Superoxide dismutase (SOD) activity and thiobarbituric acid-reactive substances (TBARS) level were also investigated. Apoptosis in the preneoplastic lesion was determined by terminal deoxynucleotidyl transferase-mediated dUTP nickend labeling (TUNEL). In addition, immunohistochemistry of β-catenin was also performed on the mucous membrane of colon. The number of large ACF (≥ 4 AC/ACF), which possess greater tumorigenic potential, was significantly lower in MZn and HZn groups compared with LZn group. Cytosolic SOD activity in the liver was significantly higher in HZn group compared with LZn group. Hepatic MDA level was decreased significantly in HZn group compared with MZn and LZn groups. Apoptotic index was significantly higher in HZn group. Taken together, these findings indicate that dietary zinc might exert a protective effect against colonic preneoplastic lesion induced by AOM/DSS in ICR mice with high iron status, and suggest that dietary supplement of zinc might play a role in suppressing colon carcinogenesis in mice.