NAG-1 up-regulation mediated by EGR-1 and p53 is critical for quercetin-induced apoptosis in HCT116 colon carcinoma cells

Fenamates: Forgotten treasure for cancer treatment and prevention: Mechanisms of action, structural modification, and bright future

Fenamates as classical nonsteroidal anti-inflammatory agents are widely used for relieving pain. Preclinical studies and epidemiological data highlight their chemo-preventive and chemotherapeutic potential for cancer. However, comprehensive reviews of fenamates in cancer are limited. To accelerate the repurposing of fenamates, this review summarizes the results of fenamates alone or in combination with existing chemotherapeutic agents. This paper also explores targets of fenamates in cancer therapy, including COX, AKR family, AR, gap junction, FTO, TEAD, DHODH, TAS2R14, ion channels, and DNA. Besides, this paper discusses other mechanisms, such as regulating Wnt/β-catenin, TGF-β, p38 MAPK, and NF-κB pathway, and the regulation of the expressions of Sp, EGR-1, NAG-1, ATF-3, ErbB2, AR, as well as the modulation of the tumor immune microenvironment. Furthermore, this paper outlined the structural modifications of fenamates, highlighting their potential as promising leads for anticancer drugs.

The evaluation of chitosan hydrogel based curcumin effect on DNMT1, DNMT3A, DNMT3B, MEG3, HOTAIR gene expression in glioblastoma cell line

BACKGROUND

Cancer is one of the most important causes of death worldwide. Some types of cancer, including glioblastoma, with a high potential for growth, invasion, and resistance to general treatments, chemotherapy, and radiotherapy, have a high potential for recurrence. Many chemical drugs have been used to treat it, but herbal drugs are more effective with fewer side effects; Therefore, this research aims to investigate the effect of curcumin-chitosan nano-complex on the expression of MEG3, HOTAIR, DNMT1, DNMT3A, DNMT3B genes in the glioblastoma cell line.

METHODS

In this research, glioblastoma cell line, PCR and spectrophotometry techniques, MTT test and transmission, field emission transmission, and fluorescent electron microscopes were used.

RESULTS

The morphological examination of the curcumin-chitosan nano-complex was without clumping, and the fluorescent microscope examination showed the nano-complex enters the cell and affects the genes expression. In its bioavailability studies, it was found that it significantly increases the death of cancer cells in a dose- and time-dependent manner. Gene expression tests showed that this nano-complex increased MEG3 gene expression compared to the control group, which is statistically significant (p < 0.05). It also decreased HOTAIR gene expression compared to the control group, which was not statistically significant (p > 0.05). It decreased the expression of DNMT1, DNMT3A, and DNMT3B genes compared to the control group, which is statistically significant (p < 0.05).

CONCLUSION

By using active plant substances such as curcumin, the active demethylation of brain cells can be directed to the path of inhibiting the growth of brain cancer cells and eliminating them.

Quercetin modulates signal transductions and targets non-coding RNAs against cancer development

In recent decades, various investigations have indicated that natural compounds have great potential in the prevention and treatment of different chronic disorders including different types of cancer. As a bioactive flavonoid, Quercetin (Qu) is a dietary ingredient enjoying high pharmacological values and health-promoting effects due to its antioxidant and anti-inflammatory characterization. Conclusive in vitro and in vivo evidence has revealed that Qu has great potential in cancer prevention and development. Qu exerts its anticancer influences by altering various cellular processes such as apoptosis, autophagy, angiogenesis, metastasis, cell cycle, and proliferation. In this way, Qu by targeting numerous signaling pathways as well as non-coding RNAs regulates several cellular mechanisms to suppress cancer occurrence and promotion. This review aimed to summarize the impact of Qu on the molecular pathways and non-coding RNAs in modulating various cancer-associated cellular mechanisms.

Targets Involved in the Anti-Cancer Activity of Quercetin in Breast, Colorectal and Liver Neoplasms

Phytochemicals have long been effective partners in the fight against several diseases, including cancer. Among these, flavonoids are valuable allies for both cancer prevention and therapy since they are known to influence a large panel of tumor-related processes. Particularly, it was revealed that quercetin, one of the most common flavonoids, controls apoptosis and inhibits migration and proliferation, events essential for the development of cancer. In this review, we collected the evidence on the anti-cancer activity of quercetin exploring the network of interactions between this flavonol and the proteins responsible for cancer onset and progression focusing on breast, colorectal and liver cancers, owing to their high worldwide incidence. Moreover, quercetin proved to be also a potentiating agent able to push further the anti-cancer activity of common employed anti-neoplastic agents, thus allowing to lower their dosages and, above all, to sensitize again resistant cancer cells. Finally, novel approaches to delivery systems can enhance quercetin's pharmacokinetics, thus boosting its great potentiality even further. Overall, quercetin has a lot of promise, given its multi-target potentiality; thus, more research is strongly encouraged to properly define its pharmaco-toxicological profile and evaluate its potential for usage in adjuvant and chemoprevention therapy.

Application of Quercetin in the Treatment of Gastrointestinal Cancers

Many cellular signaling pathways contribute to the regulation of cell proliferation, division, motility, and apoptosis. Deregulation of these pathways contributes to tumor cell initiation and tumor progression. Lately, significant attention has been focused on the use of natural products as a promising strategy in cancer treatment. Quercetin is a natural flavonol compound widely present in commonly consumed foods. Quercetin has shown significant inhibitory effects on tumor progression via various mechanisms of action. These include stimulating cell cycle arrest or/and apoptosis as well as its antioxidant properties. Herein, we summarize the therapeutic effects of quercetin in gastrointestinal cancers (pancreatic, gastric, colorectal, esophageal, hepatocellular, and oral).

Quercetin Induces Anticancer Activity by Upregulating Pro-NAG-1/GDF15 in Differentiated Thyroid Cancer Cells

Simple Summary

Thyroid cancer is one of the most common cancers worldwide, and its incidence has increased over the last few decades. It is difficult to diagnose different types of thyroid cancer. Tumor tissues from papillary thyroid cancer patient showed higher expression of mature NAG-1, whereas adjacent normal tissues showed higher expression of pro-NAG-1. Several anti-cancer compounds increased pro-NAG-1 expression in thyroid cancer cell line. Quercetin (3,3’,4’,5,7-pentahydroxyflavone) is a flavonoid that is a major component of various plants, including raspberries, grapes, and onions. Quercetin induced apoptosis by inducing only pro-NAG-1 expression, but not mature NAG-1, mediated by the transcription factor C/EBP. This study indicates that pro-NAG-1 could be used as a useful biomarker for thyroid cancer and also provides a potential therapeutic target for the treatment of thyroid cancer with quercetin.

Abstract

Although the treatment of thyroid cancer has improved, unnecessary surgeries are performed due to a lack of specific diagnostic and prognostic markers. Therefore, the identification of novel biomarkers should be considered in the diagnosis and treatment of thyroid cancer. In this study, antibody arrays were performed using tumor and adjacent normal tissues of patients with papillary thyroid cancer, and several potential biomarkers were identified. Among the candidate proteins chosen based on the antibody array data, mature NAG-1 exhibited increased expression in tumor tissues compared to adjacent normal tissues. In contrast, pro-NAG-1 expression increased in normal tissues, as assessed by western blot analysis. Furthermore, pro-NAG-1 expression was increased when the thyroid cancer cells were treated with phytochemicals and nonsteroidal anti-inflammatory drugs in a dose-dependent manner. In particular, quercetin highly induced the expression of pro-NAG-1 but not that of mature NAG-1, with enhanced anticancer activity, including apoptosis induction and cell cycle arrest. Examination of the NAG-1 promoter activity showed that p53, C/EBPα, or C/EBPδ played a role in quercetin-induced NAG-1 expression. Overall, our study indicated that NAG-1 may serve as a novel biomarker for thyroid cancer prognosis and may be used as a therapeutic target for thyroid cancers.

Natural Products in the Prevention of Metabolic Diseases: Lessons Learned from the 20th KAST Frontier Scientists Workshop

The incidence of metabolic and chronic diseases including cancer, obesity, inflammation-related diseases sharply increased in the 21st century. Major underlying causes for these diseases are inflammation and oxidative stress. Accordingly, natural products and their bioactive components are obvious therapeutic agents for these diseases, given their antioxidant and anti-inflammatory properties. Research in this area has been significantly expanded to include chemical identification of these compounds using advanced analytical techniques, determining their mechanism of action, food fortification and supplement development, and enhancing their bioavailability and bioactivity using nanotechnology. These timely topics were discussed at the 20th Frontier Scientists Workshop sponsored by the Korean Academy of Science and Technology, held at the University of Hawaii at Manoa on 23 November 2019. Scientists from South Korea and the U.S. shared their recent research under the overarching theme of Bioactive Compounds, Nanoparticles, and Disease Prevention. This review summarizes presentations at the workshop to provide current knowledge of the role of natural products in the prevention and treatment of metabolic diseases.

The Role of the Transcription Factor EGR1 in Cancer

Early growth response factor 1 (EGR1) is a transcription factor that is mainly involved in the processes of tissue injury, immune responses, and fibrosis. Recent studies have shown that EGR1 is closely related to the initiation and progression of cancer and may participate in tumor cell proliferation, invasion, and metastasis and in tumor angiogenesis. Nonetheless, the specific mechanism whereby EGR1 modulates these processes remains to be elucidated. This review article summarizes possible mechanisms of action of EGR1 in tumorigenesis and tumor progression and may serve as a reference for clinical efficacy predictions and for the discovery of new therapeutic targets.

Synthesis, Antiproliferative Activity and Radical Scavenging Ability of 5-O-Acyl Derivatives of Quercetin

Quercetin is a flavonoid that is found in many plant materials, including commonly eaten fruits and vegetables. The compound is well known for its wide range of biological activities. In this study, 5-O-acyl derivatives of quercetin were synthesised and assessed for their antiproliferative activity against the HCT116 colon cancer and MDA-MB-231 breast cancer cell lines; and their radical scavenging activity against the 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical cation and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical species. Four derivatives were found to have improved the antiproliferative activity compared to quercetin whilst retaining radical scavenging activity.

The anticancer activities of Vernonia amygdalina Delile. Leaves on 4T1 breast cancer cells through phosphoinositide 3-kinase (PI3K) pathway

Vernonia amygdalina Delile (Asteraceae) is used in traditional medicine to treat diabetes mellitus, and some research provides its activity to treat breast cancer. The aim of this study is to assess the anticancer activity of Vernonia amygdalina Delile leaves fractions on 4T1 breast cancer cells. Analysis of phytochemical compounds were carried out with LC-MS/MS. Cytotoxic activity was determined using the MTT method in the 4T1 cell line. Apoptosis, the cell cycle, and PI3K and mTOR profiles were analyzed with flow cytometry. The phytochemicals found were diterpene (ingenol-3-angelate) and some phenolics (chlorogenic acid and 4-methoxycinnamic acid), flavonoids (apigetrin, apigenin, luteolin, diosmetin, baicalin, rhoifolin, and scutellarin), and coumarines (7-hydroxycoumarine, 4-methylumbelliferone, and 4-methylumbelliferyl glucuronide). The results of the MTT assay showed that the IC₅₀ values n-hexane fraction, ethylacetate fraction (EAF), and ethanol fractions were 1,860.54 ± 93.11, 25.04 ± 0.36, and 1,940.84 ± 96.37 μg/mL, respectively. EAF induced early and late apoptosis, inhibited cell cycle progression on the G₂/M phase, and inhibited PI3K and mTOR expression. The EAF of Vernonia amygdalina Delile leaves showed anticancer activity on 4T1 breast cancer cells through induction of apoptosis, enhanced cell accumulation on G₂/M phases in the cell cycle, and inhibited expression of PI3K and mTOR.

Deciphering the Mounting Complexity of the p53 Regulatory Network in Correlation to Long Non-Coding RNAs (lncRNAs) in Ovarian Cancer

Amongst the various gynecological malignancies affecting female health globally, ovarian cancer is one of the predominant and lethal among all. The identification and functional characterization of long non-coding RNAs (lncRNAs) are made possible with the advent of RNA-seq and the advancement of computational logarithm in understanding human disease biology. LncRNAs can interact with deoxyribonucleic acid (DNA), ribonucleic acid (RNA), proteins and their combinations. Moreover, lncRNAs regulate orchestra of diverse functions including chromatin organization and transcriptional and post-transcriptional regulation. LncRNAs have conferred their critical role in key biological processes in human cancer including tumor initiation, proliferation, cell cycle, apoptosis, necroptosis, autophagy, and metastasis. The interwoven function of tumor-suppressor protein p53-linked lncRNAs in the ovarian cancer paradigm is of paramount importance. Several lncRNAs operate as p53 regulators or effectors and modulates a diverse array of functions either by participating in various signaling cascades or via interaction with different proteins. This review highlights the recent progress made in the identification of p53 associated lncRNAs while elucidating their molecular mechanisms behind the altered expression in ovarian cancer tumorigenesis. Moreover, the development of novel clinical and therapeutic strategies for targeting lncRNAs in human cancers harbors great promise.

GDF-15 as a Weight Watcher for Diabetic and Non-Diabetic People Treated With Metformin

Weight gain and obesity are global health concerns contributing to morbidity with increased risks of cardiovascular disease, diabetes, liver steatohepatitis and cancer. Pharmacological therapies or bariatric surgery are often required for those who fail to adhere to diet and lifestyle modifications. Metformin, a widely used antidiabetic agent, seems to have a health benefit beyond its anti-hyperglycemic properties, with few side effects. Emerging evidence shows weight loss to be associated with metformin in both diabetic and non-diabetic individuals. Recently, the growth differentiation factor 15 (GDF-15), a member of the transforming growth factor beta superfamily, has been identified as a key mediator of metformin-induced weight loss. Metformin increases the secretion of GDF-15, which binds exclusively to glial cell-derived neurotrophic factor family receptor alpha-like (GFRAL). This gut-brain cytokine works as a prominent player in reducing food intake and body weight in health and disease, like anorexia nervosa and cancer. Herein, we critically review advances in the understanding of the weight-reducing effects of metformin via the GDF-15 pathway.

Preparation of Quercetin Loaded Microparticles and their Antitumor Activity against Human Lung Cancer Cells (A549) in vitro

BACKGROUND

Novel quercetin-loaded microparticles (QM) were fabricated using coaxial electrospraying, characterized for surface morphology and release profile, and evaluated for antitumor activity in vitro.

METHODS

QM exhibited an average diameter of 1.69 ±1.13 mm, which was an appropriate size suitable for respiratory delivery. X-ray diffraction patterns showed that the components in QM existed in an amorphous physical form, leading to favorable interactions between the drug (quercetin), the polymer matrix (polyvinylpyrrolidone, PVP) and other excipients (sodium dodecyl sulfate and sucralose).

RESULTS

QM performed much faster release rate compared with free quercetin powder (Q) in vitro. Furthermore, QM also showed more potent inhibitory effects on A549 cell growth with reduced cell viability, decreased cell migration and induced more G0/G1 phase cell cycle arrest than Q.

CONCLUSION

Thus, the quercetin loaded microparticles exhibited more potent inhibitory effects than free quercetin on A549 cell. The increased antitumor activity could be attributed to the enhanced accumulation of quercetin in the A549 cells with the QM. However, further studies are necessary to elucidate the exact mechanisms.

Analysis of leaf flavonoid composition of some Iranian Cotoneaster Medik. (Rosaceae) species

The genus Cotoneaster consists of unarmed shrubs that naturally distributed in north parts of Iran. It is a problematic genus, and there are many discussions about its species number in Iran as well the World. Recently, M Khatamsaz has been listed 19 species of it in Iran. In the current research, we studied leaf flavonoid composition of seven Cotoneaster species from Iran. These species were harvested from the northern provinces of the country and their leaf ethanolic extracts were subjected to HPLC, for detection the types and amounts of their flavonoid compounds. We identified four flavonoid compounds: rutin, myricetin, quercetin, and kaempferol. The concentration of these flavonoids differed between the species, moreover amount of each flavonoid also varied among the studied species. All of them were registered in the studied species, except for myricetin, which was not observed in C. nummularius. The highest amount of flavonoids were detected in C. nummularius, while C. discolor had the lowest one. The evaluated species divided into four distinct group in UPGMA tree. According to CA-Joined plot, each group was characterized by species amount of flavonoid(s). All of evaluated species belonged to the same section of the genus, therefore our findings revealed that the flavonoid data were useful at sectional level for identification of the species.

Friend or foe, the role of EGR-1 in cancer

Early growth response-1 (EGR-1), also termed NEFI-A and Krox-24, as a multi-domain protein is implicated in several vital physiological processes, including development, metabolism, cell growth and proliferation. Previous studies have implied that EGR-1 was producing in response to the tissue injury, immune response and fibrosis. Meanwhile, emerging studies stressed the pronounced correlation of EGR-1 and human cancers. Nevertheless, the intricate mechanisms of cancer-reduce EGR-1 alteration still poorly characterized. In the review, we evaluated the effects of EGR-1 in tumor cell proliferation, apoptosis, migration, invasion and tumor microenvironment, and then, we dwell on the intricate signaling pathways that EGR-1 involved in. The aberrantly expressed of EGR-1 in cancers are expected to provide a new cancer therapy strategy or a new marker for assessing treatment efficacy.

Quercetin: a natural compound for ovarian cancer treatment

Ovarian cancer is the main cause of death among all reproductive cancers in females. In 2018, ovarian cancer was the seventh most common cancer of women entire the world. A wide variety of molecular and genetic alterations as well as different response to therapies in the different types of ovarian cancer lead to problems in design a common therapeutic strategy. Besides, ovarian cancer cells have tendency to acquire resistance to common cancer treatments through multiple mechanisms. Various factors, including cytokines, growth factors, proteases, adhesion molecules, coagulation factors, hormones and apoptotic agents have been examined to find effective cancer treatment. Phytochemicals have been indicated to have great potential anti-cancer properties against various types of cancers. Quercetin is one of the phytochemicals that exists extensively in daily foods. Wide evidences revealed that quercetin is able to inhibit various types of cancers including breast, lung, nasopharyngeal, kidney, colorectal, prostate, pancreatic, and ovarian cancer. Several in vitro and in vivo studied conducted to evaluate cytotoxic effects of quercetin on ovarian cancer. Since quercetin does not harm healthy cells and it is cytotoxic to cancer cells via various mechanisms, researchers suggest that it could be an ideal agent for ovarian cancer treatment or an adjuvant agent in combination with other anti-cancer drugs. Thus, in this review, we focused on chemo-preventive and curative attitude of quercetin for ovarian cancer and summarize some of the most recent findings which regard the possible molecular mechanisms by which this natural compound inhibits this cancer.

Effects of non-steroidal anti-inflammatory drug-activated gene-1 on Ganoderma lucidum polysaccharides-induced apoptosis of human prostate cancer PC-3 cells

Ganoderma lucidum polysaccharides (GLP) has been demonstrated to elicit antitumorigenic and proapoptotic activities in cancer; however, the molecular mechanisms underlying the anticancer effects of GLP have yet to be elucidated. Non-steroidal anti-inflammatory drug-activated gene-1 (NAG-1) has been reported to exert proapoptotic effects and therefore, may serve an important role in cancer prevention. The present study aimed to elucidate the molecular mechanism by which GLP stimulates anticancer activity in human prostate cancer (PCa) PC-3 cells. In addition, the role of NAG-1 in GLP-induced cancer inhibition was examined. The results of the present study demonstrated that GLP significantly inhibited cell viability in a time- and dose-dependent manner in PC-3 cells. Flow cytometry indicated that GLP induced late apoptosis, which was accompanied by poly (ADP-ribose) polymerase 1 (PARP) cleavage, and inhibition of pro-caspase-3, -6 and -9 protein expression. Furthermore, it was observed that the expression levels of NAG-1, and its transcriptional factor early growth response-1, were upregulated in a time- and dose-dependent manner upon GLP treatment. The results of a luciferase assay demonstrated that GLP induced the promoter activity of NAG-1, thus indicating that NAG-1 may be transcriptionally regulated by GLP. The secretion of NAG-1 proteins into the cell culture medium was also upregulated upon GLP treatment. Furthermore, inhibition of NAG-1 expression by small interfering RNA significantly, but not completely, prevented GLP-induced apoptosis, and reversed the effects of GLP on PARP and pro-caspase expression. It was further demonstrated that GLP inhibited the phosphorylation of protein kinase B and mitogen-activated protein kinase/extracellular signal-regulated kinase signaling in PC-3 cells. The present study is the first, to the best of our knowledge, to report that GLP may induce apoptosis of PCa cells, which is partially mediated through NAG-1 induction. The present findings may be helpful in elucidating the anticancer mechanisms of GLP through NAG-1 induction for its chemopreventive potential in PCa.

Uniting GDF15 and GFRAL: Therapeutic Opportunities in Obesity and Beyond

Growth differentiation factor-15 (GDF15) is a circulating protein that has been implicated in multiple biological processes, including energy homeostasis, body weight regulation, and cachexia driven by cancer and chronic disease. The potential to target GDF15 in the treatment of energy-intake disorders, including obesity and anorexia, is an area of intense investigation, but has been limited by the lack of an identified receptor, signaling mechanism, and target tissue. GDNF family receptor α-like (GFRAL) was recently identified as the neuronal brainstem receptor responsible for mediating the anorectic actions of GDF15. Herein, we provide a brief overview of GDF15 biology with a focus on energy homeostasis, and highlight the implications of the recent receptor identification to this field and beyond.

Quercetin: A functional dietary flavonoid with potential chemo-preventive properties in colorectal cancer

Recently, an intense attention has been paid to the application of natural compounds as a novel therapeutic strategy for cancer treatment. Quercetin, a natural flavonol present in many commonly consumed food items, is widely demonstrated to exert inhibitory effects on cancer progression through various mechanisms. Since there is a strong association with diets containing abundant vegetables, fruits, and grains, and significant decline in the risk of colon cancer, accumulation studies have focused on the anticancer potential of quercetin in colorectal cancer. Cell cycle arrest, increase in apoptosis, antioxidant replication, modulation of estrogen receptors, regulation of signaling pathways, inhibition of and metastasis and angiogenesis are among various mechanisms underlying the chemo-preventive effects of quercetin in colorectal cancer. This review covers various therapeutic interactions of Quercetin as to how targets cellular involved in cancer treatment.

Antimigration Activity of an Ethylacetate Fraction of Zanthoxylum acanthopodium DC. Fruits in 4T1 Breast Cancer Cells

Objective: This study was carried out to investigate the antimigration activity of Zanthoxylum acanthopodium DC. in the 4T1 breast cancer cell line. Methods: Zanthoxylum acanthopodium DC. fruit powder was extracted by maceration method with n-hexane and ethylacetate solvents. Cytotoxicity and proliferation were assessed using the MTT method and the cell cycle by flow cytometry. In addition, wound healing assays were conducted by a microscopic method, and expression of COX-2 and VEGFR-2 were determined using qRT-PCR. Results: The IC50 of the ethylacetate fraction (EAF) was 48.1 ± 1.06 μg/mL. The EAE at a concentration 10 μg/mL with viable cells was 62.3 ± 0.28% after 72 h incubation, with accumulation in the G2-M phase, inhibition of cell migration in the wound healing assay, and decrease in expression of COX-2 (0.62 ± 0.01) and VEGFR-2 (0.39 ± 0.003). Conclusion: The results reveal that an ethylacetate fraction of Zanthoxylum acanthopodium DC. fruits provides effective antimigration effects. Further studies are now planned to assess the potential of the ethylacetate fraction to inhibit angiogenesis in breast cancer and determine underlying mechanisms.

GL-V9 induced upregulation and mitochondrial localization of NAG-1 associates with ROS generation and cell death in hepatocellular carcinoma cells

We have previously reported that a newly synthesized compound, GL-V9 could induce mitochondria-mediated apoptosis in HepG2 cells. However, the underlying mechanisms have not been fully understood yet. In current study, we further showed that GL-V9 exhibited significant inhibitory effect on growth of several hepatocellular carcinoma cell lines. Moreover, GL-V9-induced growth inhibition was coincident with the strong upregulation of nonsteroidal anti-inflammatory drug-activated gene-1 (NAG-1), a TGFβ superfamily member, which has been linked with tumor suppression. Further analysis uncovered that GL-V9-activated p38 MAPK pathway contributed to enhancement of NAG-1 mRNA stability. Interestingly, we observed that the intracellular NAG-1 protein induced by GL-V9 could, at least in part, localize in mitochondria where it might affect protein expression, thereby resulting in dissipation of mitochondria membrane potential (MMP) and accumulation of mitochondrial superoxide, eventually facilitating to apoptosis events. Silence of NAG-1 could attenuate mitochondria related apoptosis caused by GL-V9. Moreover, GL-V9 suppressed tumor growth in xenograft model accompanied with upregulation of NAG-1 in tumor tissues. Collectively, these data demonstrated that NAG-1 could play an important role in mitochondria apoptosis triggered by GL-V9, thus providing novel mechanistic explanations and potential target for using GL-V9 as a chemotherapeutic agent against human hepatocellular carcinoma.

CXXC4 activates apoptosis through up-regulating GDF15 in gastric cancer

Worldwide, gastric cancer is one of the most fatal cancers. Epigenetic alterations in gastric cancer play important roles in silencing of tumor suppressor genes. We previously found that CXXC finger protein 4 (CXXC4) was a novel tumor suppressor in gastric cancer. In this report, we demonstrated that CXXC4 inhibited growth of gastric cancer cells as a pro-apoptotic factor. This inhibition could be reversed by the pan-caspase inhibitor called Z-VAD-FMK. However, CXXC4 with mutations in its DNA binding domain failed to induce apoptosis. Growth differentiation factor 15 (GDF15) was identified as one of potential targets responsible for CXXC4-induced apoptosis. CXXC4 activated GDF15 transcription through enhancing the interaction of transcription factor Sp1 with GDF15 promoter. In summary, the nuclear protein CXXC4 activated apoptosis in gastric cancer through up-regulating its novel potential downstream target GDF15. GDF15 might be a promising target for clinical treatment of gastric cancer with CXXC4 deficiency.

EGR-1/ASPP1 inter-regulatory loop promotes apoptosis by inhibiting cyto-protective autophagy

The decrease of ASPP1 (Apoptosis-Stimulating Protein of p53 1), a known p53 activator, has been linked to carcinogenesis and the cytotoxic resistance in various cancers, yet the underlying mechanisms of ASPP1 expression and its complex functions are not yet clear. Here, we report that ASPP1 forms an inter-regulatory loop with Early Growth Response 1 (EGR-1), and promotes apoptosis via inhibiting cyto-protective autophagy, independent of the well-documented p53-dependent mechanisms. We show that ASPP1 mRNA and protein were remarkably elevated by ectopic EGR-1 expression or endogenous EGR-1 activation, in cells with different tissue origins and p53 status. Conversely, RNAi-mediated EGR-1 knockdown suppressed ASPP1. The further mechanism studies revealed that ASPP1 promoter, mapped to -283/+88, which contained three conserved EGR-1 binding sites, was required for both binding and transactivity of EGR-1. In addition, we demonstrate that ASPP1 promoted EGR-1 in a positive feedback loop by preventing proteasome-mediated EGR-1 degradation or promoting EGR-1 nuclear import in response to anticancer natural compound Quercetin. Furthermore, albeit activating p53 in the nucleus is the well-studied function of ASPP1, we found that ASPP1 was predominately localized in the cytoplasm. Interestingly, the cytoplasmic ASPP1 retained its pro-apoptosis capability. Mechanistically, ASPP1 suppressed Atg5-Atg12 and also bound with Atg5-Atg12 to prevent its further complex formation with Atg16, resulting in the inhibition of cyto-protective autophagy. In conclusion, our results provide new insights into EGR-1/ASPP1 regulatory loop in sensitizing Quercetin-induced apoptosis. EGR-1/ASPP1, therefore, may be potentially used as therapeutic targets to improve cancer's response to pro-apoptosis treatments.

Antioxidant and Antiproliferative Activities of an Ethylacetate Fraction of Picria Fel-Terrae Lour. Herbs

Background: Excessive production of oxygen free radicals and imbalance in the mechanisms responsible for antioxidant protection may result in the onset of many diseases including breast cancer. Objective: To evaluate antiproliferative and antioxidant activity of an ethylacetate fraction (EAF) of Picria fel-terrae Lour. Herbs in the T47D cell line. Methods: Phenolic and total flavonoid contents in EAF were determined. EAF was tested for cytotoxicity and effects on the cell cycle and apoptosis, as well as antioxidant activity. Results: EAF was found to contain high levels of phenolic agents (92.88 ± 0.50 mg GAE/g), total flavonoid (84.39 ± 0.07 mg QE/g). The EAF of Picria fel-terrae Lour. herbs was found to have an IC50 of 62.98μg/mL, caused accumulation in G0-G1 and S phase and increased early and late apoptosis. Antioxidant activity in DPPH assays gave an IC50 of 166.90 ± 0.10 μg/mL. Conclusions: The results reveal that EAF of Picria fel-terrae Lour. herbs has antiproliferative activity and strong antioxidant potential. Further studies are now needed to isolate the responsible antiproliferative and antioxidant components.

Different effects of the nonsteroidal anti-inflammatory drugs meclofenamate sodium and naproxen sodium on proteasome activity in cardiac cells

The use of nonsteroidal anti-inflammatory drugs (NSAIDs) like meclofenamate sodium (MS), used to reduce pain, has been associated with an increased risk of cardiovascular disease (CVD). Naproxen (NAP), another NSAID, is not associated with increased risk of CVD. The molecular mechanism(s) by which NSAIDs induce CVD is unknown. We investigated the effects of MS and NAP on protein homeostasis and cardiotoxicity in rat cardiac H9c2 cells and murine neonatal cardiomyocytes. MS, but not NAP, significantly inhibited proteasome activity and reduced cardiac cell viability at pharmacological levels found in humans. Although proteasome subunit gene and protein expression were unaffected by NSAIDs, MS treated cell lysates showed higher 20S proteasome content, while purified proteasomes from MS treated cells had lower proteasome activity and higher levels of oxidized subunits than proteasomes from control cells. Addition of exogenous proteasome to MS treated cells improved cell viability. Both MS and NAP increased ROS production, but the rate of ROS production was greater in MS than in NAP treated cells. The ROS production is likely from mitochondria, as MS inhibited mitochondrial Complexes I and III, major sources of ROS, while NAP inhibited Complex I. MS also impaired mitochondrial membrane potential while NAP did not. Antioxidants were able to prevent the reduced cell viability caused by MS treatment. These results suggest that NSAIDs induce cardiotoxicity by a ROS dependent mechanism involving mitochondrial and proteasome dysfunction and may explain why some NSAIDs should not be given to patients for long periods.

Investigation of quercetin-induced HepG2 cell apoptosis-associated cellular biophysical alterations by atomic force microscopy

Quercetin, a wildly distributed bioflavonoid, has been proved to possess excellent antitumor activity on hepatocellular carcinoma (HCC). In the present study, the biophysical properties of HepG2 cells were qualitatively and quantitatively determined using high resolution atomic force microscopy (AFM) to understand the anticancer effects of quercetin on HCC cells at nanoscale. The results showed that quercetin could induce severe apoptosis in HepG2 cells through arrest of cell cycle and disruption of mitochondria membrane potential. Additionally, the nuclei and F-actin structures of HepG2 cells were destroyed by quercetin treatment as well. AFM morphological data showed some typical apoptotic characterization of HepG2 cells with increased particle size and roughness in the ultrastructure of cell surface upon quercetin treatment. As an important biophysical property of cells, the membrane stiffness of HepG2 cells was further quantified by AFM force measurements, which indicated that HepG2 cells became much stiffer after quercetin treatment. These results collectively suggest that quercetin can be served as a potential therapeutic agent for HCC, which not only extends our understanding of the anticancer effects of quercetin against HCC cells into nanoscale, but also highlights the applications of AFM for the investigation of anticancer drugs.

Growth differentiation factor-15 encodes a novel microRNA 3189 that functions as a potent regulator of cell death

According to the latest version of miRBase, approximately 30% of microRNAs (miRNAs) are unique to primates, but the physiological function of the vast majority remains unknown. In this study, we identified miR-3189 as a novel, p53-regulated, primate-specific miRNA embedded in the intron of the p53-target gene GDF15. Antagonizing miR-3189 increased proliferation and sensitized cells to DNA damage-induced apoptosis, suggesting a tumor suppressor function for endogenous miR-3189. Identification of genome-wide miR-3189 targets revealed that miR-3189 directly inhibits the expression of a large number of genes involved in cell cycle control and cell survival. In addition, miR-3189 downregulated the expression of multiple p53 inhibitors resulting in elevated p53 levels and upregulation of several p53 targets including p21 (CDKN1A), GADD45A and the miR-3189 host gene GDF15, suggesting miR-3189 auto-regulation. Surprisingly, miR-3189 overexpression in p53-/- cells upregulated a subset of p53-targets including GDF15, GADD45A, and NOXA, but not CDKN1A. Consistent with these results, overexpression of miR-3189 potently induced apoptosis and inhibited tumorigenicity in vivo in a p53-independent manner. Collectively, our study identified miR-3189 as a novel, primate-specific miRNA whose effects are mediated by both p53-dependent and p53-independent mechanisms. miR-3189 may, therefore, represent a novel tool that can be utilized therapeutically to induce a potent proapoptotic effect even in p53-deficient tumors.

The H6D genetic variation of GDF15 is associated with genesis, progress and prognosis in colorectal cancer

BACKGROUND

Growth differentiation factor 15 (GDF15) plays important roles in the carcinogenesis of many types of tumors. The aim of this study was to investigate whether H6D polymorphism is contributed to the genesis, progress and prognosis of colorectal cancer (CRC) in Chinese population.

METHODS

Pyrosequencing was used to determine the H6D genotypes. The relationship between the genotypes and clinical characteristics was analyzed.

RESULTS

The frequency of CG+GG genotype in the GDF15 H6D polymorphism was significantly increased in CRC patients when compared with controls [odds ratio (OR), 1.543; 95% confidence interval (95% CI), 1.138-2.094, P=0.005]. We also found that the patients with CG+GG genotype had an increased risk of death from colon cancer than those carrying homozygote CC [hazard ratio (HR), 2.472; 95% CI, 1.172-5.214; P=0.017] and the patients with CG+GG genotype of colon cancer also have a positive correlation with distant metastasis than those carrying homozygote CC (χ(2)=4.087, P=0.043). For the first time, H6D was also identified as somatic mutation when compared the H6D genotype in tumor tissues and their matched normal tissues, and the mutation rate is 7.2%. The male CRC patients with the H6D mutation were susceptible to distant metastasis (P=0.028, χ(2)=4.820) and had a relatively poor prognosis.

CONCLUSION

Our results suggest that the H6D genetic variant may be considered as a biomarker of tumorgenesis, metastasis and prognosis in colorectal cancer in Chinese population.

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.

Quercetin regresses Dalton's lymphoma growth via suppression of PI3K/AKT signaling leading to upregulation of p53 and decrease in energy metabolism

Various oncogenes are associated with deregulation in cell proliferation, apoptosis, and cell survival, which ultimately cause cancerous growth. Phosphatidylinositol 3-kinase (PI3K) mediated signaling plays a key role in malignant transformation. Cell proliferation and cell survival of tumor cell are induced by hyper activation of PI3K, AKT1, glycolytic enzyme LDH-A, and inactivation of tumor suppressor gene p53. Dietary flavonoids such as quercetin are considered a powerful modulator of different cellular signaling pathways. The present study is focused on the role of quercetin on regulation of PI3K/AKT pathways in Dalton's lymphoma mice. Effect of quercetin was analyzed in ascite cells in terms of cell viability, glycolytic metabolism as well as expression, and level of PI3K (regulatory and catalytic subunit), AKT1, and p53 using standard methods. Results reflect hyperactivation of PI3K signaling in ascite cells of Dalton's lymphoma mice, leading to activation of AKT1 and inactivation of p53. Quercetin modulates the pathway toward suppression of lymphoma. Glycolytic metabolism was also downregulated by quercetin. Its tumor suppressor activity was confirmed by morphological parameters and longevity of mice. The findings suggest that quercetin may contribute to lymphoma prevention by downregulating PI3K-AKT1-p53 pathway as well as by glycolytic metabolism.

Pro-apoptotic action of macrophage inhibitory cytokine 1 and counteraction of activating transcription factor 3 in carrageenan-exposed enterocytes

Carrageenan (CGN), a widely used food additive, has been shown to injure the epithelial barrier in animal models. This type of damage is a clinical feature of inflammatory bowel disease (IBD) in humans. In the present study, the effects of CGN on pro-apoptotic responses associated with macrophage inhibitory cytokine 1 (MIC-1) regulation in human enterocytes were evaluated. CGN up-regulated the expression of MIC-1 that promoted epithelial cell apoptosis. Although MIC-1 induction was dependent on pro-apoptotic p53 protein, the pro-survival protein activating transcription factor 3 (ATF3) was negatively regulated by p53 expression. However, MIC-1 enhanced the expression of the pro-survival protein ATF3 in enterocytes exposed to CGN. Functionally, MIC-1-mediated epithelial cell apoptosis was counteracted by the pro-survival action of ATF3 in response to CGN exposure. These findings demonstrated that the counterbalance between MIC-1 and ATF3 is critical for deciding the fate of enterocytes under the food chemical stress.

Taiwanin A targets non-steroidal anti-inflammatory drug-activated gene-1 in human lung carcinoma

Taiwanin A (α,β-bis(piperonylidene)-γ-butyrolactone) is extracted from Taiwania cryptomerioides. Taiwanin A is extracted from tree bark and exhibits antitumor activity in breast, liver, and lung cancer cell lines. The objective of this study was to demonstrate the cytotoxicity of Taiwanin A against tumor cells by increasing the expression of non-steroidal anti-inflammatory drug-activated gene-1 (NAG-1). NAG-1 has been reported to exhibit antitumor and proapoptotic activities, suggesting potential use in cancer therapy. Inhibiting NAG-1 mRNA expression in A549 reduced the cytotoxicity caused by Taiwanin A. Furthermore, the c-Jun-N-terminal kinase/Ste20-related protein proline/alanine-rich kinase (JNK/SPAK) pathway played a key role in the influence of NAG-1 on cell viability, whereas the addition of the JNK pathway inhibitor SP600125 resulted in an inhibitory effect on NAG-1 and recovery of Taiwanin-A-treated cells. A xenograft tumor model demonstrated that Taiwanin A dose-dependently significantly decreases tumor-mediated growth in nude mice by increasing the NAG-1 expression accompanying tumor apoptosis. These data supported the hypothesis that Taiwanin A inhibits lung carcinoma growth by increasing NAG-1 expression through the JNK pathway both in vivo and in vitro. This result can contribute to a compound design for increasing cytotoxicity activity in the future.

Tolfenamic acid induces apoptosis and growth inhibition in anaplastic thyroid cancer: Involvement of nonsteroidal anti-inflammatory drug-activated gene-1 expression and intracellular reactive oxygen species generation

Nonsteroidal anti-inflammatory drugs (NSAIDs) are usually used for the treatment of inflammatory diseases. However, certain NSAIDs also have antitumor activities in various cancers, including head and neck cancer, through cyclooxygenase-dependent or independent pathways. Nonsteroidal anti-inflammatory drug-activated gene-1 (NAG-1), a TGF-β superfamily protein, is induced by NSAIDs and has been shown to be induced by several antitumorigenic compounds and to exhibit proapoptotic and antitumorigenic activities. In this report, we demonstrate for the first time that tolfenamic acid (TA) transcriptionally induced the expression of NAG-1 during TA-induced apoptosis of anaplastic thyroid cancer (ATC) cells. TA reduced the viability of ATC cells in a dose-dependent manner and induced apoptosis, findings that were coincident with NAG-1 expression. Overexpression of the NAG-1 gene using cDNA enhanced the apoptotic effect of TA, whereas suppression of NAG-1 expression by small interfering RNA attenuated TA-induced apoptosis. Subsequently, we found that intracellular ROS generation plays an important role in activating the proapoptotic protein NAG-1. Then, we confirmed antitumorigenic effects of TA in a nude mouse orthotopic ATC model, and this result accompanied the augmentation of NAG-1 expression and ROS generation in tumor tissue. Taken together, these results demonstrate that TA induces apoptosis via NAG-1 expression and ROS generation in in vitro and in vivo ATC models, providing a novel mechanistic explanation and indicating a potential chemotherapeutic approach for treatment of ATC.

FOXO transcription factors control E2F1 transcriptional specificity and apoptotic function

The transcription factor E2F1 is a key regulator of proliferation and apoptosis but the molecular mechanisms that mediate these cell fate decisions remain unclear. Here, we identify FOXO transcription factors as E2F1 target genes that act in a feed-forward regulatory loop to reinforce gene induction of multiple apoptotic genes. We found that E2F1 forms a complex with FOXO1 and FOXO3. RNAi-mediated silencing of FOXO impaired E2F1 binding to the promoters of cooperative target genes. A FOXO3 mutant insensitive to inactivation by survival kinases rescued the inhibitory effect of growth factor signaling on E2F1-mediated transcription and apoptosis. The E2F1/FOXO axis is frequently blocked in cancer, as evidenced by the specific downregulation of the FOXO-dependent E2F1 transcriptional program in multiple cancer types and by the association of a reduced E2F1/FOXO transcriptional program with poor prognosis. HDAC and phosphoinositide 3-kinase (PI3K) inhibitors were identified as specific activators of E2F1/FOXO transcription, acting to enhance E2F1-induced apoptosis in a FOXO3-dependent manner. Notably, combining the histone deacetylase inhibitor vorinostat with a PI3K inhibitor led to enhanced FOXO-dependent apoptosis. Collectively, our results identify E2F1/FOXO cooperation as a regulatory mechanism that places E2F1 apoptotic activity under the control of survival signaling. Therapeutic reactivation of this tumor suppressive mechanism may offer a novel broad-acting therapy for cancer.

The radio-sensitizing effect of xanthohumol is mediated by STAT3 and EGFR suppression in doxorubicin-resistant MCF-7 human breast cancer cells

BACKGROUND

Chemotherapeutic drug resistance remains a clinical obstacle in cancer management. Drug-resistant cancer cells usually exhibit cross-resistance to ionizing radiation, which has devastating consequences for patients. With a better understanding of the molecular mechanisms, it will be possible to develop strategies to overcome this cross-resistance and to increase therapeutic sensitivity.

METHODS

Natural and synthetic flavonoid compounds including xanthohumol, the principal flavonoid in hops, were investigated for its radio-sensitizing activity on human breast cancer MCF-7 and adriamycin-resistant MCF-7 (MCF-7/ADR) cells. Chemo-sensitizing or radio-sensitizing effect was analyzed by tetrazolium-based colorimetric assay and flow cytometry. Western blot analysis, confocal microscopy, gene silencing with siRNA transfection and luciferase reporter gene assay were performed to examine signaling molecule activation.

RESULTS

Among the tested flavonoid compounds, pretreatment of the cells with xanthohumol significantly sensitized MCF-7/ADR cells to the radiation treatment by inducing apoptosis. In MCF-7/ADR cells, treatment with xanthohumol alone or with gamma-rays significantly decreased levels of anti-apoptotic proteins. Multi-drug resistance 1 (MDR1), epidermal growth factor receptor (EGFR) and signal transducer and activator of transcription 3 (STAT3) expression levels in MCF-7/ADR cells were suppressed by xanthohumol treatment. In addition, xanthohumol treatment increased death receptor (DR)-4 and DR5 expression. The xanthohumol-induced changes of these resistance-related molecules in MCF-7/ADR cells were synergistically increased by gamma-ray treatment.

CONCLUSIONS

Xanthohumol restored sensitivity of MCF-7/ADR cells to doxorubicin and radiation therapies.

GENERAL SIGNIFICANCE

Our results suggest that xanthohumol may be a potent chemo- and radio-sensitizer, and its actions are mediated through STAT3 and EGFR inhibition.

Expression and functions of galectin-7 in human and murine melanomas

The identification of galectin-7 as a p53-induced gene and its ability to induce apoptosis in many cell types support the hypothesis that galectin-7 has strong antitumor activity. This has been well documented in colon cancer. However, in some cases, such as breast cancer and lymphoma, its high expression level correlates with aggressive subtypes of cancer, suggesting that galectin-7 may have a dual role in cancer progression. In fact, in breast cancer, overexpression of galectin-7 alone is sufficient to promote metastasis to the bone and lung. In the present work, we investigated the expression and function of galectin-7 in melanoma. An analysis of datasets obtained from whole-genome profiling of human melanoma tissues revealed that galectin-7 mRNA was detected in more than 90% of biopsies of patients with nevi while its expression was more rarely found in biopsies collected from patients with malignant melanoma. This frequency, however, was likely due to the presence of normal epidermis tissues in biopsies, as shown our studies at the protein level by immunohistochemical analysis. Using the experimental melanoma B16F1 cell line, we found that melanoma cells can express galectin-7 at the primary tumor site and in lung metastasis. Moreover, we found that overexpression of galectin-7 increased the resistance of melanoma cells to apoptosis while inducing de novo egr-1 expression. Overexpression of galectin-7, however, was insufficient to modulate the growth of tumors induced by the subcutaneous injection of B16F1 cells. It also failed to modulate the dissemination of B16F1 cells to the lung.

2'-Hydroxyflavanone induces apoptosis through Egr-1 involving expression of Bax, p21, and NAG-1 in colon cancer cells

SCOPE

Natural flavanones exhibit cancer preventive and/or therapeutic effects. The objective of this study was to investigate the molecular mechanism underlying the action of the antitumor activity of hydroxyflavanone using the HCT116 colon cancer cell line.

METHODS AND RESULTS

We investigated the effect of hydroxyflavanones on antitumor activity. We found that 2'-hydroxyflavanone (2'-HF) potently inhibited the clonogenicity of HCT116 cells. 2'-HF triggered apoptosis in both wild-type and p53-null HCT116 cells, as revealed by DNA fragmentation and caspase activation. 2'-HF upregulated nonsteroidal anti-inflammatory drug-activated gene 1 (NAG-1) expression through induction of Egr-1. Silencing of NAG-1 or Egr-1 using small interfering RNA (siRNA) could attenuate 2'-HF-induced apoptosis. Egr-1 also upregulated the proapoptotic gene Bax and the cell cycle inhibitor p21.

CONCLUSION

Dietary 2'-HF may possess antitumor activity against human colon cancer.

Inhibition of GSK-3β reverses the pro-apoptotic effect of proadifen (SKF-525A) in HT-29 colon adenocarcinoma cells

Proadifen (SKF-525A) is a well-known inhibitor of cytochrome P450 monooxygenases. Besides the prevention of drug metabolism it affects the proliferation of cancer cells, although the mechanisms of possible anti-cancer activity of proadifen have not been fully understood yet. The aim of this study therefore was to evaluate the potential anti-proliferative effect of proadifen on HT-29 colon cancer cells. Our results show that proadifen inhibited the growth of HT-29 cells by the accumulation of cells in the G1 phase of the cell cycle, reduction of metabolic activity and colony formation and by the induction of apoptosis. Analyses of Western blots and flow cytometry revealed time- and dose-dependent phosphatidylserine externalization, caspase-3 activation and PARP cleavage. Intense upregulation of NAG-1 and ATF3 and downregulation of Mcl-1 and Egr-1 were also observed. Further investigation showed that NAG-1 gene silencing by siRNA had no effect on the pro-apoptotic action of proadifen. In contrast, we found that AR-A014418, the specific inhibitor of glycogen synthase kinase-3 β (GSK-3β), significantly decreased proadifen-induced apoptosis. Inactivation of GSK-3β (phosphorylation at serine 9) resulted in changes in phosphatidylserine externalization and caspase-3 activation. These data suggest that GSK-3β is an important factor in the induction of apoptosis in HT-29 colon cancer cells treated with proadifen.

In vitro antioxidant and anticancer activity of young Zingiber officinale against human breast carcinoma cell lines

BACKGROUND

Ginger is one of the most important spice crops and traditionally has been used as medicinal plant in Bangladesh. The present work is aimed to find out antioxidant and anticancer activities of two Bangladeshi ginger varieties (Fulbaria and Syedpuri) at young age grown under ambient (400 μmol/mol) and elevated (800 μmol/mol) CO2 concentrations against two human breast cancer cell lines (MCF-7 and MDA-MB-231).

METHODS

The effects of ginger on MCF-7 and MDA-MB-231 cell lines were determined using TBA (thiobarbituric acid) and MTT [3-(4,5-dimethylthiazolyl)-2,5-diphenyl-tetrazolium bromide] assays. Reversed-phase HPLC was used to assay flavonoids composition among Fulbaria and Syedpuri ginger varieties grown under increasing CO2 concentration from 400 to 800 μmol/mol.

RESULTS

Antioxidant activities in both varieties found increased significantly (P ≤ 0.05) with increasing CO2 concentration from 400 to 800 μmol/mol. High antioxidant activities were observed in the rhizomes of Syedpuri grown under elevated CO2 concentration. The results showed that enriched ginger extract (rhizomes) exhibited the highest anticancer activity on MCF-7 cancer cells with IC50 values of 34.8 and 25.7 μg/ml for Fulbaria and Syedpuri respectively. IC50 values for MDA-MB-231 exhibition were 32.53 and 30.20 μg/ml for rhizomes extract of Fulbaria and Syedpuri accordingly.

CONCLUSIONS

Fulbaria and Syedpuri possess antioxidant and anticancer properties especially when grown under elevated CO2 concentration. The use of ginger grown under elevated CO2 concentration may have potential in the treatment and prevention of cancer.

The role of NAG-1/GDF15 in the inhibition of intestinal polyps in APC/Min mice by sulindac

The antitumor effects of nonsteroidal anti-inflammatory drugs (NSAID) are assumed to be due to the inhibition of COX activity, but COX-independent mechanisms may also play an important role. NSAID-activated gene (NAG-1/GDF15) is induced by NSAIDs and has antitumorigenic activities. To determine the contribution of COX-2 inhibition and NAG-1/GDF15 expression to the prevention of colon carcinogenesis by NSAIDs, we evaluated several sulindac derivatives [des-methyl (DM)-sulindac sulfide and its prodrug DM-sulindac] that do not inhibit COX-2 activity. Sulindac sulfide and DM-sulindac induced the expression of NAG-1/GDF15 in HCT116 cells as determined by quantitative real-time PCR and Western blot. We fed APC/Min mice with 320 ppm of sulindac and doses of DM-sulindac. Only sulindac significantly inhibited tumor formation inAPC/Min mice. To determine the pharmacokinetic properties of sulindac and DM-sulindac in vivo, wild-type C57/B6 mice were fed with sulindac and DM-sulindac at 80, 160, and 320 ppm. High-performance liquid chromatography analysis revealed that the conversion of DM-sulindac to DM-sulindac sulfide (active form) was less efficient than the conversion of sulindac to sulindac sulfide (active form) in the mice. Lower levels of DM-sulindac sulfide accumulated in intestinal and colon tissues in comparison with sulindac sulfide. In addition, NAG-1/GDF15 was induced in the liver of sulindac-fed mice but not in the DM-sulindac-fed mice. Collectively, our results suggest that the tumor-inhibitory effects of sulindac in APC/Min mice may be due to, in part, NAG-1/GDF15 induction in the liver. Our study also suggests that pharmacologic properties should be carefully evaluated when developing drug candidates.

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.