Suppression of tumor growth and invasion in 9,10 dimethyl benz(a) anthracene induced mammary carcinoma by the plant bioflavonoid quercetin

Quercetin Induces Mitochondrial Apoptosis and Downregulates Ganglioside GD3 Expression in Melanoma Cells

Malignant melanoma represents a form of skin cancer characterized by a bleak prognosis and heightened resistance to traditional therapies. Quercetin has demonstrated notable anti-carcinogenic, anti-inflammatory, anti-oxidant, and pharmacological effects across various cancer types. However, the intricate relationship between quercetin's anti-cancer properties and ganglioside expression in melanoma remains incompletely understood. In this study, quercetin manifests specific anti-proliferative, anti-migratory, and cell-cycle arrest effects, inducing mitochondrial dysfunction and apoptosis in two melanoma cancer cell lines. This positions quercetin as a promising candidate for treating malignant melanoma. Moreover, our investigation indicates that quercetin significantly reduces the expression levels of ganglioside GD3 and its synthetic enzyme. Notably, this reduction is achieved through the inhibition of the FAK/paxillin/Akt signaling pathway, which plays a crucial role in cancer development. Taken together, our findings suggest that quercetin may be a potent anti-cancer drug candidate for the treatment of malignant melanoma.

Caesalpinia pulcherrima lowered serum carcinoembryonic antigen and antigen 125 in 7,12-Dimethylbenz[a]anthracene-induced Mammary Carcinogenesis in Female Albino Rats

Aim

This study is aimed at evaluating the anticancer effect of the aqueous extract of Caesalpinia pulcherrima (L.) Sw in 7,12-Dimethlbenz[a]anthracene (DMBA) - induced mammary cancer.

Methods

Tumors were induced via a single intraperitoneal injection of DMBA (dissolved in olive oil) at a dose of 80 mg/kg body weight to the test rats and allowed to develop for about four months. They were treated with cyclophosphamide and an aqueous extract of Caesalpinia pulcherrima at doses of 10 and 250 mg/kg body weight, respectively, for 28 days. Serum levels of cancer antigen 125 (CA125), carcinoembryonic antigen (CEA) activity, cyclooxygenase-2 (COX-2), and cytochrome p450 oxidase (cytp450) activity, as well as other diagnostic enzymes, were estimated.

Results

The result revealed that DMBA is associated with a significant (p < 0.05) increase in the serum levels of CA125, CEA, COX-2, cytp450, lactate dehydrogenase (LDH), alkaline phosphatase (ALP), aspartate aminotransferase (AST), and alanine aminotransferase (ALT) of the rats, thus suggesting tumor-promoting and hepatotoxic effects of DMBA. There was also a significant (p < 0.05) reduction of serum levels of these cancer and liver biomarker enzymes in the groups treated with cyclophosphamide and Caesalpinia pulcherrima compared to the untreated group, thus suggesting anticancer activity of Caesalpinia pulcherrima. The anticancer effect of Caesalpinia pulcherrima was further confirmed by the disappearance of infiltrative fibrous cells and the absence of inflammatory cells from the photomicrographs of the rats treated with Caesalpinia pulcherrima.

Conclusion

Our findings show that Caesalpinia pulcherrima possesses anticancer activity, and could protect against mammary cancer.

Emergence of nutrigenomics and dietary components as a complementary therapy in cancer prevention

Cancer is an illness characterized by abnormal cell development and the capability to infiltrate or spread to rest of the body. A tumor is the term for this abnormal growth that develops in solid tissues like an organ, muscle, or bone and can spread to other parts of the body through the blood and lymphatic systems. Nutrition is a critical and immortal environmental component in the development of all living organisms encoding the relationship between a person's nutrition and their genes. Nutrients have the ability to modify gene expression and persuade alterations in DNA and protein molecules which is researched scientifically in nutrigenomics. These interactions have a significant impact on the pharmacokinetic properties of bioactive dietary components as well as their site of action/molecular targets. Nutrigenomics encompasses nutrigenetics, epigenetics, and transcriptomics as well as other "omic" disciplines like proteomics and metabolomics to explain the vast disparities in cancer risk among people with roughly similar life style. Clinical trials and researches have evidenced that alternation of dietary habits is potentially one of the key approaches for reducing cancer risk in an individual. In this article, we will target how nutrigenomics and functional food work as preventive therapy in reducing the risk of cancer.

Quercetin increases mitochondrial proteins (VDAC and SDH) and downmodulates AXL and PIM-1 tyrosine kinase receptors in NRAS melanoma cells

Melanoma is a type of skin cancer with low survival rates after it has metastasized. In order to find molecular differences that could represent targets of quercetin in anti-melanoma activity, we have chosen SKMEL-103 and SKMEL-28 melanoma cells and human melanocytes as models. Firstly, we observed that quercetin was able in reducing SKMEL-103 cell viability, but not in SKMEL-28. Besides that, quercetin treatment caused inhibition of AXL in both cell lines, but upregulation of PIM-1 in SKMEL-28 and downregulation in SKMEL-103. Moreover, HIF-1 alpha expression decreased in both cell lines. Interestingly, quercetin was more effective against SKMEL-103 than kinases inhibitors, such as Imatinib, Temsirolimus, U0126, and Erlotinib. Interestingly, we observed that while the levels of succinate dehydrogenase and voltage-dependent anion channel increased in SKMEL-103, both proteins were downregulated in SKMEL-28 after quercetin's treatment. Furthermore, AKT, AXL, PIM-1, ABL kinases were much more active and chaperones HSP90, HSP70 and GAPDH were highly expressed in SKMEL-103 cells in comparison with melanocytes. Our findings indicate, for the first time, that the efficacy of quercetin to kill melanoma cells depends on its ability in inhibiting tyrosine kinase and upregulating mitochondrial proteins, at least when SKMEL-103 and SKMEL-28 cells response were compared.

Folate receptor targeted delivery of paclitaxel to breast cancer cells via folic acid conjugated graphene oxide grafted methyl acrylate nanocarrier

The adaptability, joint with a large surface area, electronic flexibility, high intrinsic mobility, high mechanical strength and supreme thermal conductivity have condensed graphene family materials attractive as technological tools of the drug delivery system. In this present study, investigate a modified graphene oxide-methyl acrylate (GO-g-MA) nanocarrier for targeted anti-cancer drug delivery in breast cancer cells and the GO-g-MA fascinated with folic acidas a targeting ligand to target the cancer cells. Paclitaxel (PTX) was assembled through π-π stacking, hydrophophic interaction on the surface of the GO-g-MA/FA carrier. Structural modification of GO-g-MA, functionalization of targeting ligands GO-g-MA/FA and drug loaded GO-g-MA/FA-PTX was characterized and confirmed through FTIR, XRD, SEM,TEM and AFM analysis. The in-vitro drug release pattern of PTX from the GO-g-MA/FA was examined in different pH ranges. An MTT assay was performed to evaluate the cytotoxicity behaviour of the carrier and PTX loaded nanocarrier in the human breast cancer cell line (MDA-MB-231). GO-g-MA/FA-PTX carrier showed that 39% of cytotoxic effect. Furthermore, the in-vivo (DMBA induced breast cancer rats) studies were carried out and treatment with PTX- loaded GO-g-MA/FA nanocarrier attenuates the levels of mitochondrial citric acids enzymes to near normal.

Biological Mechanisms by Which Antiproliferative Actions of Resveratrol Are Minimized

Preclinical and clinical studies have offered evidence for protective effects of various polyphenol-rich foods against cardiovascular diseases, neurodegenerative diseases, and cancers. Resveratrol is among the most widely studied polyphenols. However, the preventive and treatment effectiveness of resveratrol in cancer remain controversial because of certain limitations in existing studies. For example, studies of the activity of resveratrol against cancer cell lines in vitro have often been conducted at concentrations in the low μM to mM range, whereas dietary resveratrol or resveratrol-containing wine rarely achieve nM concentrations in the clinic. While the mechanisms underlying the failure of resveratrol to inhibit cancer growth in the intact organism are not fully understood, the interference by thyroid hormones with the anticancer activity of resveratrol have been well documented in both in vitro and xenograft studies. Thus, endogenous thyroid hormones may explain the failure of anticancer actions of resveratrol in intact animals, or in the clinic. In this review, mechanisms involved in resveratrol-induced antiproliferation and effects of thyroid hormones on these mechanisms are discussed.

New insights into therapeutic activity and anticancer properties of curcumin

Natural compounds obtained from plants are capable of garnering considerable attention from the scientific community, primarily due to their ability to check and prevent the onset and progress of cancer. These natural compounds are primarily used due to their nontoxic nature and the fewer side effects they cause compared to chemotherapeutic drugs. Furthermore, such natural products perform even better when given as an adjuvant along with traditional chemotherapeutic drugs, thereby enhancing the potential of chemotherapeutics and simultaneously reducing their undesired side effects. Curcumin, a naturally occurring polyphenol compound found in the plant Curcuma longa, is used as an Indian spice. It regulates not only the various pathways of the immune system, cell cycle checkpoints, apoptosis, and antioxidant response but also numerous intracellular targets, including pathways and protein molecules controlling tumor progression. Many recent studies conducted by major research groups around the globe suggest the use of curcumin as a chemopreventive adjuvant molecule to maximize and minimize the desired effects and side effects of chemotherapeutic drugs. However, low bioavailability of a curcumin molecule is the primary challenge encountered in adjuvant therapy. This review explores different therapeutic interactions of curcumin along with its targeted pathways and molecules that are involved in the regulation of onset and progression of different types of cancers, cancer treatment, and the strategies to overcome bioavailability issues and new targets of curcumin in the ever-growing field of cancer.

Impact of Phytochemicals and Dietary Patterns on Epigenome and Cancer

Cancer remains one of the leading causes of death around the world. Initially it is recognized as a genetic disease, but now it is known to involve epigenetic abnormalities along with genetic alterations. Epigenetics refers to heritable changes that are not encoded in the DNA sequence itself, but play an important role in the control of gene expression. It includes changes in DNA methylation, histone modifications, and RNA interference. Although it is heritable, environmental factors such as diet could directly influence epigenetic mechanisms in humans. This article will focus on the role of dietary patterns and phytochemicals that have been demonstrated to influence the epigenome and more precisely histone and non-histone proteins modulation by acetylation that helps to induce apoptosis and phosphorylation inhibition, which counteracts with cells proliferation. Recent developments discussed here enhance our understanding of how dietary intervention could be beneficial in preventing or treating cancer and improving health outcomes.

Inhibitory Effects of γ- and δ-Tocopherols on Estrogen-Stimulated Breast Cancer In Vitro and In Vivo

Estrogens have been implicated as complete carcinogens for breast and other tissues through mechanisms involving increased cell proliferation, oxidative stress, and DNA damage. Because of their potent antioxidant activity and other effects, tocopherols have been shown to exert antitumor activities in various cancers. However, limited information is available on the effect of different forms of tocopherols in estrogen-mediated breast cancer. To address this, we examined the effects of α-, γ-, and δ-tocopherols as well as a natural γ-tocopherol-rich mixture of tocopherols, γ-TmT, on estrogen-stimulated MCF-7 cells in vitro and in vivo For the in vivo studies, MCF-7 cells were injected into the mammary fat pad of immunodeficient mice previously implanted with estrogen pellets. Mice were then administered diets containing 0.2% α-, γ-, δ-tocopherol, or γ-TmT for 5 weeks. Treatment with α-, γ-, δ-tocopherols, and γ-TmT reduced tumor volumes by 29% (P < 0.05), 45% (P < 0.05), 41% (P < 0.05), and 58% (P < 0.01), as well as tumor weights by 20%, 37% (P < 0.05), 39% (P < 0.05), and 52% (P < 0.05), respectively. γ- and δ-tocopherols and γ-TmT inhibited the expression of cell proliferation-related genes such as cyclin D1 and c-Myc, and estrogen-related genes such as TFF/pS2, cathepsin D, and progesterone receptor in estrogen-stimulated MCF-7 cells in vitro Further, γ- and δ-tocopherols decreased the levels of estrogen-induced oxidative stress and nitrosative stress markers, 8-hydroxy-2'-deoxyguanosine and nitrotyrosine, as well as the DNA damage marker, γ-H2AX. Our results suggest that γ- and δ-tocopherols and the γ-tocopherol-rich mixture are effective natural agents for the prevention and treatment of estrogen-mediated breast cancer. Cancer Prev Res; 10(3); 188-97. ©2017 AACR.

Chemopreventive Agents and Inhibitors of Cancer Hallmarks: May Citrus Offer New Perspectives?

Fruits and vegetables have long been recognized as potentially important in the prevention of cancer risk. Thus, scientific interest in nutrition and cancer has grown over time, as shown by increasing number of experimental studies about the relationship between diet and cancer development. This review attempts to provide an insight into the anti-cancer effects of Citrus fruits, with a focus on their bioactive compounds, elucidating the main cellular and molecular mechanisms through which they may protect against cancer. Scientific literature was selected for this review with the aim of collecting the relevant experimental evidence for the anti-cancer effects of Citrus fruits and their flavonoids. The findings discussed in this review strongly support their potential as anti-cancer agents, and may represent a scientific basis to develop nutraceuticals, food supplements, or complementary and alternative drugs in a context of a multi-target pharmacological strategy in the oncology.

Structural insights into the polypharmacological activity of quercetin on serine/threonine kinases

Polypharmacology, the discovery or design of drug molecules that can simultaneously interact with multiple targets, is gaining interest in contemporary drug discovery. Serine/threonine kinases are attractive targets for therapeutic intervention in oncology due to their role in cellular phosphorylation and altered expression in cancer. Quercetin, a naturally occurring flavonoid, inhibits multiple cancer cell lines and is used as an anticancer drug in Phase I clinical trial. Quercetin glycosides have also received some attention due to their high bioavailability and activity against various diseases including cancer. However, these have been studied to a lesser extent. In this study, the structural basis of the multitarget inhibitory activity of quercetin and isoquercitrin, a glycoside derivative, on serine/threonine kinases using molecular modeling was explored. Structural analysis showed that both quercetin and isoquercitrin exhibited good binding energies and interacted with aspartate in the highly conserved Asp–Phe–Gly motif. The results indicate that isoquercitrin could be a more potent inhibitor of several members of the serine/threonine kinase family. In summary, the current structural evaluation highlights the multitarget inhibitory property of quercetin and its potential to be a chemical platform for oncological polypharmacology.

Gold nanoparticle-conjugated quercetin inhibits epithelial-mesenchymal transition, angiogenesis and invasiveness via EGFR/VEGFR-2-mediated pathway in breast cancer

OBJECTIVES

Epidermal growth factor plays a critical role in breast malignancies by enhancing cell proliferation, invasion, angiogenesis and metastasis. Epithelial-mesenchymal transition (EMT) is a crucial process by which epithelial cells lose polarity and acquire migratory mesenchymal properties. Gold nanoparticles are an efficient drug delivery vehicle for carrying chemotherapeutic agents to target cancer cells and quercetin is an anti-oxidative flavonoid known with potent anti-malignant cell activity.

MATERIALS AND METHODS

Cell viability was assessed by MTT assay, and protein expression was examined by Western blotting and immunocytochemistry. Cell invasion was monitored using invasion chambers, and cell migration was analysed by scratch wound-healing assay. In vitro and ex vivo angiogenesis studies were performed by capillary-like tube formation assay and chick embryo angiogenesis assay (CEA). 7,12-dimethylbenz(a)anthracene (DMBA) induced mammary carcinoma in Sprague-Dawley rats.

RESULTS

We observed a significant reduction in protein expression of vimentin, N-cadherin, Snail, Slug, Twist, MMP-2, MMP-9, p-EGFR, VEGFR-2, p-PI3K, Akt and p-GSK3β, and enhanced E-cadherin protein expression in response to AuNPs-Qu-5 treatment. AuNPs-Qu-5 inhibited migration and invasion of MCF-7 and MDA-MB-231 cells compared to free quercetin. AuNPs-Qu-5-treated HUVECs had reduced cell viability and capillary-like tube formation. In vitro and in vivo angiogenesis assays showed that AuNPs-Qu-5 suppressed tube and new blood vessel formation. Treatment with AuNPs-Qu-5 impeded tumour growth in DMBA-induced mammary carcinoma in SD rats compared to treatment with free quercetin.

CONCLUSION

Our results suggest that AuNPs-Qu-5 inhibited EMT, angiogenesis and metastasis of the breast cancer cells tested by targeting the EGFR/VEGFR-2 signalling pathway.

Anticancer Efficacy of Polyphenols and Their Combinations

Polyphenols, found abundantly in plants, display many anticarcinogenic properties including their inhibitory effects on cancer cell proliferation, tumor growth, angiogenesis, metastasis, and inflammation as well as inducing apoptosis. In addition, they can modulate immune system response and protect normal cells against free radicals damage. Most investigations on anticancer mechanisms of polyphenols were conducted with individual compounds. However, several studies, including ours, have indicated that anti-cancer efficacy and scope of action can be further enhanced by combining them synergistically with chemically similar or different compounds. While most studies investigated the anti-cancer effects of combinations of two or three compounds, we used more comprehensive mixtures of specific polyphenols and mixtures of polyphenols with vitamins, amino acids and other micronutrients. The mixture containing quercetin, curcumin, green tea, cruciferex, and resveratrol (PB) demonstrated significant inhibition of the growth of Fanconi anemia head and neck squamous cell carcinoma and dose-dependent inhibition of cell proliferation, matrix metalloproteinase (MMP)-2 and -9 secretion, cell migration and invasion through Matrigel. PB was found effective in inhibition of fibrosarcoma HT-1080 and melanoma A2058 cell proliferation, MMP-2 and -9 expression, invasion through Matrigel and inducing apoptosis, important parameters for cancer prevention. A combination of polyphenols (quercetin and green tea extract) with vitamin C, amino acids and other micronutrients (EPQ) demonstrated significant suppression of ovarian cancer ES-2 xenograft tumor growth and suppression of ovarian tumor growth and lung metastasis from IP injection of ovarian cancer A-2780 cells. The EPQ mixture without quercetin (NM) also has shown potent anticancer activity in vivo and in vitro in a few dozen cancer cell lines by inhibiting tumor growth and metastasis, MMP-2 and -9 secretion, invasion, angiogenesis, and cell growth as well as induction of apoptosis. The presence of vitamin C, amino acids and other micronutrients could enhance inhibitory effect of epigallocatechin gallate (EGCG) on secretion of MMPs. In addition, enrichment of NM with quercetin (EPQ mix) enhanced anticancer activity of NM in vivo. In conclusion, polyphenols, especially in combination with other polyphenols or micronutrients, have been shown to be effective against multiple targets in cancer development and progression, and should be considered as safe and effective approaches in cancer prevention and therapy.

Chemistry and pharmacology of Bidens pilosa: an overview

Bidens pilosa L. is an edible herb and has been traditionally used for a wide range of ailments in many countries. The aim of this review is to present comprehensive information of the chemical constituents, nutraceutical and ethnomedical uses as well as the biological and pharmacological effects and toxicity of this plant based on 218 literary sources reported over 40 years. Major chemical constituents (including 301 compounds) belonging to polyacetylenes, polyacetylene glycosides, flavonoids, flavone glycosides, aurones, chalcones, okanin glycosides, phenolic acids, terpenes, pheophytins, fatty acids and phytosterols have been identified or isolated from the different parts of this plant. Many of them have been considered as the bioactive compounds which are potentially responsible for the pharmacological actions. Various types of preparations, extracts and individual compounds derived from this plant have been found to possess biological and pharmacological activities such as anti-malarial, anti-allergy, anti-hypertensive and smooth muscle relaxant, anti-cancerogenic, anti-diabetic, anti-inflammatory, anti-microbial, antioxidant. The results of data analysis on the chemicals, pharmacological and toxicological characteristics of B. pilosa validate the view of its folk worldwide-medicinal uses. This herb has a great beneficial therapeutic property and is possibly used for complement or alternative to pharmaceutical drugs in some specific cases. However, this herb is known as hyperaccumulator and as-excluder; therefore, harvesting the herb for medicinal uses should be judiciously cautioned.

Role of dietary bioactive natural products in estrogen receptor-positive breast cancer

Estrogen receptor (ER)-positive breast cancer, including luminal-A and -B, is the most common type of breast cancer. Extended exposure to estrogen is associated with an increased risk of breast cancer. Both ER-dependent and ER-independent mechanisms have been implicated in estrogen-mediated carcinogenesis. The ER-dependent pathway involves cell growth and proliferation triggered by the binding of estrogen to the ER. The ER-independent mechanisms depend on the metabolism of estrogen to generate genotoxic metabolites, free radicals and reactive oxygen species to induce breast cancer. A better understanding of the mechanisms that drive ER-positive breast cancer will help optimize targeted approaches to prevent or treat breast cancer. A growing emphasis is being placed on alternative medicine and dietary approaches toward the prevention and treatment of breast cancer. Many natural products and bioactive compounds found in foods have been shown to inhibit breast carcinogenesis via inhibition of estrogen induced oxidative stress as well as ER signaling. This review summarizes the role of bioactive natural products that are involved in the prevention and treatment of estrogen-related and ER-positive breast cancer.

Quercetin and Tryptanthrin: Two Broad Spectrum Anticancer Agents for Future Chemotherapeutic Interventions

The idea and practice of developing or identifying compounds capable of eliminating the transformed cells or cancer cells without being nontoxic to their normal counterparts deserves much importance. Since ages, plants have been considered and proven to be repertoires of chemicals possessing immense therapeutic potential. A proportion of these plant-derived compounds or phytochemicals were shown to be highly competent anticancer agents besides being effective against many other diseases. Representative compounds of different classes of phytochemicals are in clinical use against cancer. In this chapter, we discuss the anticancer potential of two compounds: quercetin, a flavonoid and tryptanthrin, an indoloquinazoline alkaloid, and the mechanisms behind their cytotoxic effects on cancers of different origin. The chapter also gives a brief mention of their properties that make them effective against cancer.

Anti-tumor potential of nitroxyl derivative Pirolin in the DMBA-induced rat mammary carcinoma model: A comparison with quercetin

BACKGROUND

Considering the role of oxidative stress in carcinogenesis, we investigated the effect of synthetic antioxidant Pirolin (3-carbamoyl-2,2,5,5-tetramethylpyrroline-1-oxyl) on breast cancer progression. Since the anticancer drugs may cause cardiotoxicity due to oxidative stress in the heart muscle, we also evaluated Pirolin performance in heart tissue and compared its effect with that of the natural dietary flavonoid quercetin.

METHODS

Sprague-Dawley rats were administered with 7,12-dimethylbenz(a)anthracene (DMBA) and then treated ip with an antioxidant (each at a dose of 10mg/kg b.w.) for 14 days. The histopathology of tumors, their size and multiplicity were assesed. The effect of antioxidants on heart tissue was evaluated by the oxidative stress markers and poly (ADP-ribose) polymerase 1 (PARP 1) cleavage.

RESULTS

The median number of tumors and their volume, at the end of the study, were considerably smaller in both antioxidant-treated groups. We found a better antioxidative performance of quercetin in the heart, since a restoration of the GSH pool and decreased amount of hydroperoxides were observed. Antioxidants did not prevent cardiomyocytes from apoptosis.

CONCLUSION

The attenuation of tumor progression by Pirolin was comparable with the action of quercetin. No negative changes were observed in the heart of animals after Pirolin treatment. Thus, its use in targeting deregulated redox pathways should be further studied.

The flavonoid quercetin: possible solution for anthracycline-induced cardiotoxicity and multidrug resistance

Anthracycline chemotherapy is often used in the treatment of various malignancies. Its application, however, encounters several limitations due to development of serious side effects, mainly cardiotoxicity and may be ineffective due to multidrug resistance (MDR). Many different compounds have been evaluated as poorly effective in the protection against anthracycline side effects and in the prevention from MDR. Thus, continuous investigational efforts are necessary to find valuable protectants and the flavonoid quercetin (Q) seems to be a promising candidate. It is present in relatively high amounts in a human diet and the lack of its toxicity, including genotoxicity has been confirmed. The structure of Q favours its high antioxidant activity, the potential to inhibit the activity of oxidative enzymes and to interact with membrane transporter proteins responsible for development of MDR, e.g. P-glycoprotein. Furthermore, Q can influence cellular signalling and gene expression, and thus, alter response to exogenous genotoxicants and oxidative stress in normal cells. It accounts for its chemopreventive and anticancer properties. Overall, these properties might indicate the possibility of application of Q as cardioprotectant during anthracycline chemotherapy. Moreover, numerous biological properties displayed by Q might possibly result in the reversal of MDR in tumour cells and improve the efficacy of chemotherapy. However, these beneficial effects towards anthracycline-induced complications of chemotherapy have to be further explored and confirmed both in animal and clinical studies. Concurrently, investigations aimed at improvement of the bioavailability of Q and further elucidation of its metabolism after application in combination with anthracyclines are needed.

A flavonoid isolated from Streptomyces sp. (ERINLG-4) induces apoptosis in human lung cancer A549 cells through p53 and cytochrome c release caspase dependant pathway

The aim of this study was to investigate the anticancer activity of a flavonoid type of compound isolated from soil derived filamentous bacterium Streptomyces sp. (ERINLG-4) and to explore the molecular mechanisms of action. Cytotoxic properties of ethyl acetate extract was carried out against A549 lung cancer cell line using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. Cytotoxic properties of isolated compound were investigated in A549 lung cancer cell line, COLO320DM cancer cell line and Vero cells. The compound showed potent cytotoxic properties against A549 lung cancer cell line and moderate cytotoxic properties against COLO320DM cancer cell line. Isolated compound showed no toxicity up to 2000 μg/mL in Vero cells. So we have chosen the A549 lung cancer cell line for further anticancer studies. Intracellular visualization was done by using a laser scanning confocal microscope. Apoptosis was measured using DNA fragmentation technique. Treatment of the A549 cancer cells with isolated compound significantly reduced cell proliferation, increased formation of fragmented DNA and apoptotic body. Activation of caspase-9 and caspase-3 indicated that compound may be inducing intrinsic and extrinsic apoptosis pathways. Bcl-2, p53, pro-caspases, caspase-3, caspase-9 and cytochrome c release were detected by western blotting analysis after compound treatment (123 and 164 μM). The activities of pro-caspases-3, caspase-9 cleaved to caspase-3 and caspase-9 gradually increased after the addition of isolated compound. But Bcl-2 protein was down regulated after treatment with isolated compound. Molecular docking studies showed that the compound bound stably to the active sites of caspase-3 and caspase-9. These results strongly suggest that the isolated compound induces apoptosis in A549 cancer cells via caspase activation through cytochrome c release from mitochondria. The present results might provide helpful suggestions for the design of antitumor drugs toward lung cancer treatment.

The chemopreventive capacity of quercetin to induce programmed cell death in hepatocarcinogenesis

In this study of chemoprevention in the rat modified resistant hepatocyte model, preneoplastic cells were diminished by >60% with quercetin pretreatment compared with those rats treated with N-Diethylnitrosamine (DEN) to induce liver cancer. This decrease occurred associated with an abolished DEN-induced lipid peroxidation as well as activation of caspase 9 and increased caspase 3, as determined by increased expression of cleaved caspase 3 and 9, but not cleaved caspase 8 and increased fragmentation of Poly (ADP-ribose) polymerase (PARP) inducing apoptosis of presumed genetically injured cells, when quercetin was administered before the initiation agent.

Quercetin suppresses cytochrome P450 mediated ROS generation and NFκB activation to inhibit the development of 7,12-dimethylbenz[a]anthracene (DMBA) induced hamster buccal pouch carcinomas

Increased production of reactive oxygen species (ROS) has long been recognized to play a pivotal role in carcinogenesis. Quercetin, a naturally occurring dietary flavonoid is known for its ROS scavenging properties. The present study was designed to investigate the chemopreventive and chemotherapeutic effects of quercetin based on cytochrome P450 (CYP) mediated ROS generation, ROS-induced cellular damage and activation of the NFκB signalling circuit during 7,12-dimethylbenz[a]anthracene (DMBA)-induced hamster buccal pouch (HBP) carcinogenesis. Administration of quercetin inhibited the development of DMBA-induced HBP carcinomas by impairing CYP-mediated ROS production via downregulation of the expression of CYP1A1 and CYP1B1, and upregulation of antioxidant defences. Attenuation of ROS generation by quercetin in turn abrogated NFκB signalling by preventing the phosphorylation and degradation of IκB, nuclear translocation of NFκB and transactivation of its target genes associated with cell proliferation and apoptosis evasion. Thus dietary flavonoids such as quercetin that can block ROS generation and inhibit the redox regulated transcription factor NFκB, by virtue of their antioxidant potential are promising candidates for future antioxidant-based anticancer regimens.

Quercetin and cancer chemoprevention

Several molecules present in the diet, including flavonoids, can inhibit the growth of cancer cells with an ability to act as "chemopreventers". Their cancer-preventive effects have been attributed to various mechanisms, including the induction of cell-cycle arrest and/or apoptosis as well as the antioxidant functions. The antioxidant activity of chemopreventers has recently received a great interest, essentially because oxidative stress participates in the initiation and progression of different pathological conditions, including cancer. Since antioxidants are capable of preventing oxidative damage, the wide use of natural food-derived antioxidants is receiving greater attention as potential anti-carcinogens. Among flavonoids, quercetin (Qu) is considered an excellent free-radical scavenging antioxidant, even if such an activity strongly depends on the intracellular availability of reduced glutathione. Apart from antioxidant activity, Qu also exerts a direct, pro-apoptotic effect in tumor cells, and can indeed block the growth of several human cancer cell lines at different phases of the cell cycle. Both these effects have been documented in a wide variety of cellular models as well as in animal models. The high toxicity exerted by Qu on cancer cells perfectly matches with the almost total absence of any damages for normal, non-transformed cells. In this review we discuss the molecular mechanisms that are based on the biological effects of Qu, and their relevance for human health.

Interfering with ROS Metabolism in Cancer Cells: The Potential Role of Quercetin

A main feature of cancer cells, when compared to normal ones, is a persistent pro-oxidative state that leads to an intrinsic oxidative stress. Cancer cells have higher levels of reactive oxygen species (ROS) than normal cells, and ROS are, in turn, responsible for the maintenance of the cancer phenotype. Persistent ROS stress may induce adaptive stress responses, enabling cancer cells to survive with high levels of ROS and maintain cellular viability. However, excessive ROS levels render cancer cells highly susceptible to quercetin, one of the main dietary flavonoids. Quercetin depletes intracellular glutathione and increases intracellular ROS to a level that can cause cell death.

Natural occurring polyphenols as template for drug design. Focus on serine proteases

Several major physio-pathological processes, including cancer, inflammatory states and thrombosis, are all strongly dependent upon the fine regulation of proteolytic enzyme activities, and dramatic are the consequences of unbalanced equilibria between enzymes and their cognate inhibitors. In this perspective, the discovery of small-molecule ligands able to modulate catalytic activities has a massive therapeutic potential and is a stimulating goal. Numerous recent experimental evidences revealed that proteolytic enzymes can be opportunely targeted, reporting on small ligands capable of binding to these biological macromolecules with drug-like potencies, and primarily with comparable (or even higher) efficiency with respect to their endogenous binding partner. In particular, natural occurring polyphenols and their derivatives recently disclosed these intriguing abilities, making them promising templates for drug design and development. In this review, we compared the inhibitory capacities of a set of monomeric polyphenols toward serine proteases activity, and finally summarized the data with an emphasis on the derivation of a pharmacophore model.

Capsaicin alleviates the imbalance in xenobiotic metabolizing enzymes and tumor markers during experimental lung tumorigenesis

Lung cancer is currently a leading cause of death all over the world. Environmental risk factors, particularly genotoxic chemicals such as polycyclic aromatic hydrocarbons (PAH), are likely to account for a much higher mortality. Xenobiotic metabolizing enzymes are potentially chief determinants in both the susceptibility to the mutagenic effects of chemical carcinogens and in the response of tumors to chemotherapy. The well-known carcinogen benzo(a)pyrene (B(a)P) of PAH family was given orally (50 mg/kg body weight) to induce lung cancer in Swiss albino mice. B(a)P induction altered the levels of cytochromes (P450, b5), activities of phase I biotransformation enzymes (NADPH-cytochrome P450 reductase, NADH-cytochrome b5 reductase and epoxide hydrolase), phase II enzymes (glutathione-S-transferase, UDP-glucuronyl transferase and DT-diaphorase), and the levels of serum tumor markers. Treatment with capsaicin (CAP) (10 mg/kg body weight) to the lung carcinoma mice restored back the activities of phase I and II biotransformation enzymes and the levels of tumor markers to near normalcy. The above findings were substantiated by immunoblotting and immunohistochemical analysis of cytochrome P450 1A1 (CYP1A1) in the lung tissues. Our present study unravels that CAP can effectively detoxify the carcinogens which discloses its anti-carcinogenic effect during experimental lung cancer.

Chemoprevention of rat mammary carcinogenesis by Azadirachta indica leaf fractions: modulation of hormone status, xenobiotic-metabolizing enzymes, oxidative stress, cell proliferation and apoptosis

We evaluated the chemopreventive potential of the ethyl acetate fraction (EAF) and methanolic fraction (MF) of Azadirachta indica (neem) leaf on 7,12-dimethylbenz[a]anthracene (DMBA)-induced rat mammary carcinogenesis. Estradiol and estrogen receptor status, xenobiotic-metabolizing enzyme activities, redox status, DNA and protein modifications, and the expression of cell proliferation, and apoptosis related proteins in the mammary gland and liver were used as biomarkers of chemoprevention. Administration of both EAF and MF at a dose of 10mg/kg bw effectively suppressed tumour incidence. Chemoprevention by neem leaf fractions was associated with modulation of hormone and receptor status, xenobiotic-metabolising enzymes, and lipid and protein oxidation, with upregulation of antioxidants, inhibition of oxidative DNA damage, protein modification, and cell proliferation, and induction of apoptosis. However EAF rich in constituent phytochemicals was more effective than MF in modulating multiple molecular targets. These results provide evidence for the chemopreventive efficacy of neem leaf fractions in the rat mammary tumour model.

Effects of Quercetin on invasion and midkine expression of human esophageal cancer cell

AIM: To observe the effects of Quercetin on the invasion of human esophageal cancer cells, and to investigate the possible mechanism.

METHODS: Human esophageal cancer cell line EC109 was treated with different concentrations of Quercetin, and then the anchorage independence growth of EC109 cells was studied by colony formation in soft agar; the invasion ability of EC109 cells was determined by Boyden chamber, and the expression levels of midkine mRNA and protein were detected by real time RT-PCR and Western blot assay, respectively.

RESULTS: After Quercetin treatment, the malignant proliferation and invasive ability of EC109 cells were obviously decreased, which showed a dose-dependent manner (all P < 0.05). Meanwhile, Quercetin down-regulated the expression of midkine mRNA and protein in a dose- and time-dependent manner (all P < 0.05).

CONCLUSION: Quercetin can inhibit the invasion of EC109 cells by down-regulating midkine expression.

Study of the antitumor potential of Bidens pilosa (Asteraceae) used in Brazilian folk medicine

AIM OF THE STUDY

Bidens pilosa (L.) (Asteraceae) is a medicinal plant traditionally used in Brazil for treating conditions that can be related to cancer. Therefore the present study was carried out to evaluate the antitumor activity of extracts obtained from the aerial parts of this plant species.

MATERIALS AND METHODS

The crude hydroalcoholic extract (HAE) (water:alcohol, 6:4) and solvent fractions (chloroform=CHCl3,ethyl acetate=EtOAc, methanol=MeOH) were assessed for cytotoxicity assay by the brine shrimp and hemolytic, MTT and NRU assays. The antiproliferative potential of the crude extract and fractions was investigated in vivo using the Ehrlich ascites carcinoma (EAC) in isogenic Balb/c mice that were administered intraperitoneally 150 and 300 mg/kg body weight per day for nine days beginning 24 h after tumor inoculation.

RESULTS

In in vitro cytotoxicity using Ehrlich ascites carcinoma cell line assay CHCl3 extract proved to be more toxic than the crude HAE with an IC(50) of 97+/-7.2 and 83+/-5.2 microg/mL to NRU and MTT, respectively. Histomorphological evaluations indicated that the treatment with CHCl3 and HAE extracts significantly reduced (P<0.05) body weight, abdominal circumference, tumor volume, packed cell volume and viable cell count, when compared to EAC control group. Furthermore, nonviable tumor cell count increased significantly (P<0.01) only under treatment with CHCl3 or HAE, and this was accompanied by a marked percentage increase in life span (54.2 and 41.7%, respectively). Biochemical assays revealed that CHCl3 and HAE extracts were also able to decrease serum LDH activity (39.5 and 30.6%) and GSH concentration (94.6 and 50.7%) in ascitic fluid, respectively.

CONCLUSION

The chloroform fraction showed the best and methanolic the worst antitumor activity.

Antiplasmin activity of natural occurring polyphenols

The equilibrium between proteolytic enzymes and their cognate inhibitors is crucial in a number of physiological as well as pathological processes, including cancer, inflammatory processes and thrombosis. Therefore, both synthetic and natural small molecule inhibitors are object of extensive studies as drugs in the treatment of these pathologies. Two natural occurring polyphenolic compounds, representative of glycosylated and unglycosylated flavonoid structures, namely quercetin and rutin, were thereby tested as potential ligands of plasmin(ogen), a serine (pro)protease, whose role in tumor cell invasion and migration has been reported. Quercetin showed a ten folds higher affinity with plasmin with respect to rutin in terms of equilibrium dissociation constant, both compounds acting as in vitro moderate reversible inhibitors; additionally, quercetin and rutin prevented plasmin-incubated BB1 cells from releasing E-cadherin fragment to a different extent, respectively. Furthermore, a feasible mechanism of interaction was analyzed and discussed using a molecular modeling approach.

A critical review of the data related to the safety of quercetin and lack of evidence of in vivo toxicity, including lack of genotoxic/carcinogenic properties

Quercetin is a naturally-occurring flavonol (a member of the flavonoid family of compounds) that has a long history of consumption as part of the normal human diet. Because a number of biological properties of quercetin may be beneficial to human health, interest in the addition of this flavonol to various traditional food products has been increasing. Prior to the use of quercetin in food applications that would increase intake beyond that from naturally-occurring levels of the flavonol in the typical Western diet, its safety needs to be established or confirmed. This review provides a critical examination of the scientific literature associated with the safety of quercetin. Results of numerous genotoxicity and mutagenicity, short- and long-term animal, and human studies are reviewed in the context of quercetin exposure in vivo. To reconcile results of in vitro studies, which consistently demonstrated quercetin-related mutagenicity to the absence of carcinogenicity in vivo, the mechanisms that lead to the apparent in vitro mutagenicity, and those that ensure absence of quercetin toxicity in vivo are discussed. The weight of the available evidence supports the safety of quercetin for addition to food.