Cancer chemoprevention: a radical perspective

In Vitro Modulation of Genotoxicity and Oxidative Stress by Polyphenol-Rich Fraction of Chinese Ladder Brake (Pteris vittata L.)

Pteris vittata L. is a terrestrial genus growing in moist, shady forests and on hillsides. The plant has considerable ethnomedicinal importance. Investigations have been carried out on chemical profiling and antioxidant compounds from some genera of pteridophytes but studies on the biological properties of P. vittata are lacking. Therefore, the present study investigates antioxidant, antigenotoxic, and antiproliferative potential of the aqueous fraction of P. vittata (PWE). A battery of assays were carried out to assess the antioxidant potential of the PWE. SOS chromotest and DNA nicking assay were used to evaluate the antigenotoxicity of the fraction. The cytotoxic effect of PWE was analyzed using MTT and Neutral Single Cell Gel Electrophoresis comet assay. EC50 of 90.188 µg/ml, 80.13 µg/ml, 142.836 µg/ml, and 12.274 µg/ml was obtained in DPPH, superoxide anion scavenging, reducing power and lipid peroxidation assays, respectively. PWE was potent in inhibiting Fenton's reagent-induced nicking of pBR322 plasmid. The fraction significantly inhibited hydrogen peroxide (H2O2) and 4-nitroquinoline-N-oxide (4NQO) induced mutagenicity and a reduction in induction factor was found with increased PWE concentration. GI50 of 147.16 µg/ml was obtained in MTT assay in human MCF-7 breast cancer cell line. PWE induced apoptosis as confirmed from confocal microscopy studies. The protective effects can be attributed to the presence of the phytochemicals in PWE. These results will be helpful in the development of functional food characteristics, as well as unravel the benefits of pteridophytes as promoters of health.

Cocoa powder and fermented jackfruit seed flour: A comparative cell-based study on their potential antioxidant and anti-inflammatory activities after simulated gastrointestinal digestion

BACKGROUND

Jackfruit seed flour can be used as a cocoa aroma replacer with similar technological properties. The purpose of this study was to investigate the in vivo toxicity and in vitro antioxidant activity of fermented jackfruit seed flour (Fjs) and non-alkaline cocoa powder (Nac).

RESULTS

Fjs and Nac extracts (Fjs-E and Nac-E) were produced and submitted to in vitro gastrointestinal digestion producing digested fractions named Fjs-D and Nac-D, respectively. Nac-E showed over two-fold higher oxygen radical absorbance capacity (ORAC) than Fjs-E. However, after simulated gastrointestinal digestion (in vitro), there were no significant differences between Nac-D and Fjs-D (P < 0.01). Similarly, the cellular antioxidant activity (CAA) of Nac-D and Fjs-D was not significantly different (P < 0.01). The anti-inflammatory assay in transgenic RAW 264.7 murine macrophages showed that Fjs-E did not affect cell viability up to 300 μg mL^-1 (P > 0.05) and reduced by 15% the release of TNF-α (P < 0.05). Fjs-D did not affect cell viability up to 300 μg mL^-1 (P > 0.05) and showed 58% reduction of NF-κB activation (P < 0.05), with no effects on TNF-α levels. Treatment with Nac-E up to 300 μg mL^-1 did not decrease cell viability (P > 0.05) and reduced the release of TNF-α levels by 34% and 66% at 100 and 300 μg mL^-1 , respectively (P < 0.05). Nac-D did not reduce the NF-κB activation or TNF-α levels at any tested concentration.

CONCLUSION

Collectively, these findings indicate that Fjs is a safe and promising functional ingredient with biological activities even after gastrointestinal digestion. © 2023 Society of Chemical Industry.

Effect of total glycosides of Cistanche deserticola on the energy metabolism of human HepG2 cells

To study the anti-tumor effect of Cistanche deserticola Y. Ma, HepG2 cells were treated with 0, 3.5, 10.5, 21, 31.5, and 42 μg/ml of total glycosides (TG) from Cistanche deserticola. The HepG2 cell survival rate and 50% inhibition concentration (IC₅₀) were detected using the CCK-8 method, and the level of reactive oxygen species (ROS) was detected by using a DCFH-DA fluorescence probe. Finally, a Seahorse XFe24 energy analyzer (Agilent, United States) was used to detect cell mitochondrial pressure and glycolytic pressure. The results showed that TG could reduce the survival rate of HepG2 cells and that the IC₅₀ level was 35.28 μg/ml. With increasing TG concentration, the level of ROS showed a concentration-dependent upward trend. Energy metabolism showed that each dose group of TG could significantly decline the mitochondrial respiratory and glycolytic functions of HepG2 cells. In conclusion, TG could significantly inhibit the mitochondrial respiration and glycolysis functions of HepG2 cells, increase the level of ROS, and inhibit cell proliferation. Thus, this experiment pointed out that Cistanche deserticola can be used as a source of anti-cancer foods or drugs in the future. However, further studies on its mechanisms and clinical applications are needed.

Antioxidants status and physiological responses to early and late heat stress in two rabbit breeds

Early life heat stress negatively affects rabbit production and well-being. However, the physiological response to acute heat stress in later life is not clearly defined. The present study aims to investigate the effects of early and late heat stress at 36°C on some blood constituents, antioxidant enzymes activity in the blood, and muscle in New Zealand white and Baladi Black rabbits. A total of sixty post-weaning rabbits of each breed were randomly divided into two groups; control groups (NZWC and BBC) and early heat-stressed groups for six hours at 36 ± 1°C and 62% relative humidity (RH) (NZWT and BBT groups). After heat stress, six rabbits from each group were slaughtered for blood and muscle tissue collection. The surviving rabbits were kept at 28 ± 1°C and 40% RH till 13 weeks of age. At the end of 13 weeks, all rabbits were exposed to late heat stress as precious described to perform four groups: single late stressed groups; NZWC2, BBC2, and double stressed groups; NZWT2 and BBT2. After late heat stress, six rabbits from each group were slaughtered for blood and muscle tissue collection. The early and late heat stress caused a significant reduction in the blood creatine kinase, lactate dehydrogenase, and high-density lipoprotein and antioxidant enzymes' activity in blood and muscle of both NZW and BB rabbits compared with the control groups. While, the blood total cholesterol, triglycerides, total lipids levels, and lipid peroxidation activity in blood and muscle were significantly increased due to the early and late heat-stressed both breeds compared with the control groups. It could be concluded that the early heat stress at 36°C has negative effects on several physiological indicators and antioxidant activities in the blood and muscle of NZW and BB rabbits.

Selenocompounds and Sepsis-Redox Bypass Hypothesis: Part B-Selenocompounds in the Management of Early Sepsis

Significance: Endothelial barrier damage, which is in part caused by excess production of reactive oxygen, halogen and nitrogen species (ROHNS), especially peroxynitrite (ONOO^-), is a major event in early sepsis and, with leukocyte hyperactivation, part of the generalized dysregulated immune response to infection, which may even become a complex maladaptive state. Selenoenzymes have major antioxidant functions. Their synthesis is related to the need to limit deleterious oxidant redox cycling by small selenocompounds, which may be of therapeutic cytotoxic interest. Plasma selenoprotein-P is crucial for selenium transport from the liver to the tissues and for antioxidant endothelial protection, especially against ONOO^-. Above micromolar concentrations, sodium selenite (Na₂SeO₃) becomes cytotoxic, with a lower cytotoxicity threshold in activated cells, which has led to cancer research. Recent Advances: Plasma selenium (<2% of total body selenium) is mainly contained in selenoprotein-P, and concentrations decrease rapidly in the early phase of sepsis, because of increased selenoprotein-P binding and downregulation of hepatic synthesis and excretion. At low concentrations, Na₂SeO₃ acts as a selenium donor, favoring selenoprotein-P synthesis in physiology, but probably not in the acute phase of sepsis. Critical Issues: The cytotoxic effects of Na₂SeO₃ against hyperactivated leukocytes, especially the most immature forms that liberate ROHNS, may be beneficial, but they may also be harmful for activated endothelial cells. Endothelial protection against ROHNS by selenoprotein-P may reduce Na₂SeO₃ toxicity, which is increased in sepsis. Future Direction: The combination of selenoprotein-P for endothelial protection and the cytotoxic effects of Na₂SeO₃ against hyperactivated leukocytes may be a promising intervention for early sepsis. Antioxid. Redox Signal. 37, 998-1029.

Marine-derived pipeline anticancer natural products: a review of their pharmacotherapeutic potential and molecular mechanisms

Background

Cancer is a complex and most widespread disease and its prevalence is increasing worldwide, more in countries that are witnessing urbanization and rapid industrialization changes. Although tremendous progress has been made, the interest in targeting cancer has grown rapidly every year. This review underscores the importance of preventive and therapeutic strategies.

Main text

Natural products (NPs) from various sources including plants have always played a crucial role in cancer treatment. In this growing list, numerous unique secondary metabolites from marine sources have added and gaining attention and became potential players in drug discovery and development for various biomedical applications. Many NPs found in nature that normally contain both pharmacological and biological activity employed in pharmaceutical industry predominantly in anticancer pharmaceuticals because of their enormous range of structure entities with unique functional groups that attract and inspire for the creation of several new drug leads through synthetic chemistry. Although terrestrial medicinal plants have been the focus for the development of NPs, however, in the last three decades, marine origins that include invertebrates, plants, algae, and bacteria have unearthed numerous novel pharmaceutical compounds, generally referred as marine NPs and are evolving continuously as discipline in the molecular targeted drug discovery with the inclusion of advanced screening tools which revolutionized and became the component of antitumor modern research.

Conclusions

This comprehensive review summarizes some important and interesting pipeline marine NPs such as Salinosporamide A, Dolastatin derivatives, Aplidine/plitidepsin (Aplidin®) and Coibamide A, their anticancer properties and describes their mechanisms of action (MoA) with their efficacy and clinical potential as they have attracted interest for potential use in the treatment of various types of cancers.

Selenocompounds and Sepsis: Redox Bypass Hypothesis for Early Diagnosis and Treatment: Part A-Early Acute Phase of Sepsis: An Extraordinary Redox Situation (Leukocyte/Endothelium Interaction Leading to Endothelial Damage)

Significance: Sepsis is a health disaster. In sepsis, an initial, beneficial local immune response against infection evolves rapidly into a generalized, dysregulated response or a state of chaos, leading to multiple organ failure. Use of life-sustaining supportive therapies creates an unnatural condition, enabling the complex cascades of the sepsis response to develop in patients who would otherwise die. Multiple attempts to control sepsis at an early stage have been unsuccessful. Recent Advances: Major events in early sepsis include activation and binding of leukocytes and endothelial cells in the microcirculation, damage of the endothelial surface layer (ESL), and a decrease in the plasma concentration of the antioxidant enzyme, selenoprotein-P. These events induce an increase in intracellular redox potential and lymphocyte apoptosis, whereas apoptosis is delayed in monocytes and neutrophils. They also induce endothelial mitochondrial and cell damage. Critical Issues: Neutrophil production increases dramatically, and aggressive immature forms are released. Leukocyte cross talk with other leukocytes and with damaged endothelial cells amplifies the inflammatory response. The release of large quantities of reactive oxygen, halogen, and nitrogen species as a result of the leukocyte respiratory burst, endothelial mitochondrial damage, and ischemia/reperfusion processes, along with the marked decrease in selenoprotein-P concentrations, leads to peroxynitrite damage of the ESL, reducing flow and damaging the endothelial barrier. Future Directions: Endothelial barrier damage by activated leukocytes is a time-sensitive event in sepsis, occurring within hours and representing the first step toward organ failure and death. Reducing or stopping this event is necessary before irreversible damage occurs.

Lepidium sativum and Its Biogenic Silver Nanoparticles Activate Immune Cells and Induce Apoptosis and Cell Cycle Arrest in HT-29 Colon Cancer Cells

There is an increased demand for plants with antioxidants and anticancer properties. Lepidium sativum L. is an edible plant with medical importance. In this study, we aimed to investigate the anticancer activity; antioxidant capacity and antibacterial impact of Lepidium sativum L. seed acetone extract (LSSAExt), alone and with its biogenic silver nanoparticles (AgNPs). LSSAExt-produced AgNPs were characterized using SEM, XRD and Vis/UV analysis. Biomolecules in LSSAExt and LSSAExt + AgNPs were explored utilizing FTIR. The ability of LSSAExt and LSSAExt + AgNPs to induce apoptosis and mitotic cell arrest in the HT-29 colon cancer cells, compared to normal and repeated cell division activated splenic cells was determined by florescent stains and flow cytometry. Antibacterial power was tested using well diffusion technique. LSSAExt and LSSAExt + AgNPs showed a good antibacterial impact. LSSAExt contains ROS, which could help in cancer cells apoptosis. LSSAExt and LSSAExt+AgNPs were not toxic to splenic cells and increased the rate of their cell division. LSSAExt and LSSAExt+AgNPs increased p53 expression and could arrest cell division of HT-29 colon cancer cells but not of normal fast dividing cells. LSSAExt and LSSAExt+AgNPs caused apoptosis in cancer cells rather than necrosis. In conclusion, acetone preparation of the edible plant L. sativum is a good antibacterial agent, good anticancer preparation at least against colon cancer as it is shown to be targeted, effective and can boost immune cells.

Comparison of Anticancer Effects of Hydroalcoholic Extracts of Camellia sinensis and Lepidium sativum L on HeLa Cell Line

Background: The antioxidative activity of green tea and garden cress extract is of interest in cancer. Objectives: The current study aimed at evaluating the effect of hydroalcoholic extracts of Lepidium sativum (cress) and Camellia sinensis (green tea) on the culture medium of the HeLa cell line. Methods: Dulbecco’s Modified Eagle’s medium (DMEM) containing 10% fetal bovine serum (FBS) was used to culture HeLa cells, which was exposed to the different concentrations of green tea and cress extracts at 24 hours and 48 hours. Cell viability and apoptotic cells were quantified by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide or MTT assay and propidium iodide, respectively. Results: The highest percentage of growth inhibition (85%) was observed at 100 μg/mL of the green tea extract after 48-hour treatment. The percentage of growth inhibition at 24 h after treatment was 83% for green tea (P > 0.05). The high growth inhibition percentage of HeLa cells at 100 μg/mL of cress extract at 24 hours and 48 hours (49.8%) after treatment was 27.92% and 49.8%, respectively (P > 0.05). Additionally, the cell apoptosis assay indicated that green tea and cress extracts had toxic effects on the HeLa cells. This effect was highest at the concentration of 100 μg/mL and more evident in green tea. Conclusions: It can be concluded that green tea extract compared with cress had a more cytotoxic effect against cervical cancer.

Oxidative Stress in Cancer

Contingent upon concentration, reactive oxygen species (ROS) influence cancer evolution in apparently contradictory ways, either initiating/stimulating tumorigenesis and supporting transformation/proliferation of cancer cells or causing cell death. To accommodate high ROS levels, tumor cells modify sulfur-based metabolism, NADPH generation, and the activity of antioxidant transcription factors. During initiation, genetic changes enable cell survival under high ROS levels by activating antioxidant transcription factors or increasing NADPH via the pentose phosphate pathway (PPP). During progression and metastasis, tumor cells adapt to oxidative stress by increasing NADPH in various ways, including activation of AMPK, the PPP, and reductive glutamine and folate metabolism.

Oxyresveratrol extracted from Artocarpus heterophyllus Lam. inhibits tyrosinase and age pigments in vitro and in vivo

We extracted and purified oxyresveratrol (OXY) from Artocarpus heterophyllus Lam. and identified its structure. The kinetics and mechanisms of OXY-induced mushroom tyrosinase inhibition were studied using fluorescence spectroscopy, copper ion chelation, and circular dichroism (CD). We found that OXY significantly inhibited tyrosinase with a half maximal inhibitory concentration (IC₅₀) of 0.03 mM. The inhibitory effect of OXY on tyrosinase was almost 25 times that of kojic acid, which had an IC₅₀ of 0.78 mM. Additionally, OXY and the tyrosinase substrate L-dopa did not have a competitive relationship; OXY is a non-competitive inhibitor. Using a fluorescence quenching experiment, we determined the corresponding rate constant (K_q) values at 298, 303, and 310 K to be 2.24 × 10¹², 1.08 × 10¹² and 1.44 × 10¹² L mol^-1 s^-1, respectively. The OXY and tyrosinase interaction occured mainly through van der Waals forces and a hydrogen bond between the -OH group and its amino acid residue. Furthermore, we investigated the effects of OXY on murine melanoma B16 cells and on age pigments in Caenorhabditis elegans (C. elegans). OXY decreased melanin production by inhibiting the tyrosinase activity in murine melanoma B16 cells, which decreased superoxide dismutase (SOD) and glutathione peroxidase (GSH) and increased catalase (CAT), leading to apoptosis. The lifespan of nematodes in the 50 ml resveratrol-treated group was significantly longer than that in the blank group by 5%. The mean lifespan of nematodes in the 50 μM OXY-treated group was significantly longer than that in the blank group by 6.82%.The fluorescence intensity of C. elegans pigments decreased by 30.43%, 47.35% and 64.42% after the treatment with a low, middle, and high OXY dose, respectively, showing that OXY has a significant inhibitory effect on melanin and age pigment production.

Interactions between bioactive components determine antioxidant, cytotoxic and nutrigenomic activity of cocoa powder extract

Numerous studies have shown, rather disappointingly, that isolated bioactive phytochemicals are not as biologically effective as natural plant products. Such a discrepancy may be explained by the concept of food synergy, which was verified in this research for cocoa extract versus its major components with regard to cancer chemoprevention. The evaluation embraced the relationship between redox properties evaluated in cell-free systems with the aid of free radicals scavenging method and differential pulse voltammetry, and redox associated anticarcinogenic activities (cellular antioxidant activity, cytotoxicity, nutrigenomic activity) in human colon adenocarcinoma cell line exposed to either cocoa powder extract or artificial mixtures of cocoa bioactives at matching concentrations. In contrast to expectations, our results showed that the stepwise enrichment with antioxidants caused no gradual increase in the antioxidant activity of the model mixtures; also, these model mixtures did not reach the reducing potential of cocoa in the cell-free systems or cellular model employed. Further, the biological activities examined in colon adenocarcinoma cells did not alter in a stepwise manner that could reflect the gradual changes in composition of bioactive ingredients. In conclusion, the experiments presented here showed that the growing complexity of a mixture of phytochemicals seems to create a new redox bioactive substance rather than enrich the mixture with new activities, characteristic of the compound added. It follows that no simple, predictable relationship can be expected between the chemopreventive potential and the composition of real food items containing a complicated set of non-toxic redox active ingredients. Our observations suggest that the interactions between different bioactive compounds and food matrix components are cooperating factors determining the final bioactivity of foods.

Chemical Aspects of Biological Activity of Isothiocyanates and Indoles, the Products of Glucosinolate Decomposition

There is growing evidence that cancer chemoprevention employing natural, bioactive compounds may halt or at least slow down the different stages of carcinogenesis. A particularly advantageous effect is attributed to derivatives of sulfur-organic phytochemicals, such as glucosinolates (GLs) synthesized mainly in Brassicaceae plant family. GLs are hydrolysed enzymatically to bioactive isothiocyanates (ITC) and indoles, which exhibit strong anti-inflammatory and anti-carcinogenic activity. Highly bioavailable electrophilic ITC are of particular interest, as they can react with nucleophilic groups of important biomolecules to form dithiocarbamates, thiocarbamates and thioureas. These modifications seem responsible for the chemopreventive activity, but also for genotoxicity and mutagenicity. It was documented that ITC can permanently bind to important biomolecules such as glutathione, cytoskeleton proteins, transcription factors NF-κB and Nrf2, thiol-disulfide oxidoreductases, proteasome proteins or heat shock proteins. Furthermore, ITC may also affect epigenetic regulation of gene expression, e.g. by inhibition of histone deacetylases. Some other derivatives of glucosinolates, especially indoles, are able to form covalent bonds with nucleobases in DNA, which may result in genotoxicity and mutagenicity. This article summarizes the current state of knowledge about glucosinolates and their degradation products in terms of possible interactions with reactive groups of cellular molecules.

Identifying chemopreventive agents for obesity-associated cancers using an efficient, 3D high-throughput transformation assay

Obesity is associated with ~40% of cancer diagnoses but there are currently no effective preventive strategies, illustrating a need for chemoprevention. We previously demonstrated that fibroblast growth factor 2 (FGF2) from adipose tissue stimulates malignant transformation, as measured by growth in soft agar, the gold-standard in vitro transformation assay. Because the soft agar assay is unsuitable for high throughput screens (HTS), we developed a novel method using 3D growth in ultra-low attachment conditions as an alternative to growth in agar to discover compounds that inhibit transformation. Treating non-tumorigenic, skin epithelial JB6 P⁺ cells with FGF2 stimulates growth in ultra-low attachment conditions analogous to growth in the soft agar. This transformation HTS identified picropodophyllin, an insulin growth factor 1 receptor (IGF1R) inhibitor, and fluvastatin, an HMG-CoA reductase inhibitor, as potential chemopreventive agents. These compounds were validated for efficacy using two non-tumorigenic cell lines in soft agar. Another IGF1R inhibitor and other statins were also tested and several were able to inhibit growth in soft agar. This novel 3D HTS platform is fast, robust and has the potential to identify agents for obesity-associated cancer prevention.

Suppression of proliferation and activation of cell death by sodium selenite involves mitochondria and lysosomes in chemoresistant bladder cancer cells

The specific effects of sodium selenite (selenite) on a chemoresistant human bladder cancer cell line RT-112/D21 were investigated during 72 h. Selenite at low concentration of 2.5 μmol (otherwise tolerated in normal urothelial cells UROtsa) suppressed growth and proliferation of the tested cancer cells via induced oxidative stress. Selenite further altered mitochondrial functions (i.e. decreased mitochondrial membrane potential, increased production of superoxide and reduced ATP synthesis), disrupted lysosomal membranes and activated autophagy. These changes in selenite-exposed cells ultimately resulted in their demise via necrosis and other cell death modality displaying heterotypic apoptotic and autophagic features.

Detarium microcarpum: A novel source of nutrition and medicine: A review

Detarium microcarpum is a plant indigenous to Africa, which occurs naturally in many African countries, particularly in savannah regions. Its leaves and fruits are used mainly as food and as folk medicine. It has anti-diabetic, antioxidant, and hepatitis C inhibitor properties and has been traditionally utilised in cancer treatment. This review examines published work on the nutritional, pharmacological, and traditional uses of Detarium microcarpum. This plant may become valuable if the fruit, stems, roots, and leaves are extracted for nutraceutical purposes.

Synthesis, characterization and ROS-mediated antitumor effects of palladium(II) complexes of curcuminoids

Based on the synthesis of curcumin and its derivatives from aromatic aldehydes, a novel series of palladium(II) complexes with curcumin (or its derivatives) and 2,2'-bipyridine have been synthesized through a directed self-assembly approach that involves spontaneous deprotonation of the curcuminoid ligands in H₂O/acetone solution. These complexes have been characterized by ¹H (¹³C) NMR, HRMS and elemental analysis. Crystal structure of 3h has been determined by X-ray diffraction analysis. Their cytotoxicity was tested by MTT. The preliminary results showed that complexes 3d, 3f, 3h have significant inhibition on proliferation of three carcinoma cells such as MCF-7, HeLa and A549 cells, which were more active than cisplatin. Further mechanistic studies indicated that the tested complex 3h arrested the cell cycle in the S phase and can disrupted mitochondrial membrane potential and induced tumor cell apoptosis through reactive oxygen species (ROS)-dependent pathway.

Chemoprevention using folic acid for dysplastic lesions of the larynx

Folate deficiency may be directly associated with carcinogenesis. Folate supplementation may reduce the risk of progression in a mucosa that is already genetically altered. The aim of the present study was to determine the role of folic acid in the treatment of mild and moderate laryngeal dysplasia recurring after surgery. The data obtained by laryngoscopy, measurement of serum folate levels and functional vocal assessment with the GIRBAS scale and VHI questionnaire were compared in patients who had received folic acid with a homogeneous group of patients with dysplasia who had not undergone any therapy. A total of 24 patients suffering from recurrence of mild or moderate laryngeal dysplasia (n=12, group A) were treated with 400 mg folic acid per os, once daily for 6 months. The patients in group B (n=12) received no treatment and were used as the control group. In group A, 7 (58%) patients exhibited a complete response, with clinically evident regression of leukoplakia, 3 (25%) displayed a partial decrease in the lesions with reduced volume of the area involved, whereas 2 patients exhibited no change. As regards patients in control group B, 8 (67%) exhibited no change, in 1 case there was a spontaneous regression, and in 3 (25%) there was disease progression with suspected malignant transformation, leading to repeat surgery. Therefore, folate deficiency may be considered to be a factor predisposing to precancerous lesions, and dietary folate supplementation may prevent and reduce the emergence of cancer.

Green tea polyphenols induce cell death in breast cancer MCF-7 cells through induction of cell cycle arrest and mitochondrial-mediated apoptosis

In order to study the molecular mechanisms of green tea polyphenols (GTPs) in treatment or prevention of breast cancer, the cytotoxic effects of GTPs on five human cell lines (MCF-7, A549, Hela, PC3, and HepG2 cells) were determined and the antitumor mechanisms of GTPs in MCF-7 cells were analyzed. The results showed that GTPs exhibited a broad spectrum of inhibition against the detected cancer cell lines, particularly the MCF-7 cells. Studies on the mechanisms revealed that the main modes of cell death induced by GTPs were cell cycle arrest and mitochondrial-mediated apoptosis. Flow cytometric analysis showed that GTPs mediated cell cycle arrest at both G1/M and G2/M transitions. GTP dose dependently led to apoptosis of MCF-7 cells via the mitochondrial pathways, as evidenced by induction of chromatin condensation, reduction of mitochondrial membrane potential (ΔΨ_m), improvement in the generation of reactive oxygen species (ROS), induction of DNA fragmentation, and activations of caspase-3 and caspase-9 in the present paper.

Polyphenols delivery by polymeric materials: challenges in cancer treatment

Nanotechnology can offer different solutions for enhancing the therapeutic efficiency of polyphenols, a class of natural products widely explored for a potential applicability for the treatment of different diseases including cancer. While possessing interesting anticancer properties, polyphenols suffer from low stability and unfavorable pharmacokinetics, and thus suitable carriers are required when planning a therapeutic protocol. In the present review, an overview of the different strategies based on polymeric materials is presented, with the aim to highlight the strengths and the weaknesses of each approach and offer a platform of ideas for researchers working in the field.

Magnesium, zinc, arsenic, selenium and platinum urinary excretion from cancer patients of Antofagasta region, Chile: multi-metal approach

Objectives

To evaluate the short-term 24 h urinary excretion of platinum, arsenic, selenium, magnesium and zinc in patients with lung cancer and with cancer other than lungs treated with cisplatin or/and carboplatin from Antofagasta, Chile.

Design

Urine measurements of Pt and Se were made by inductively coupled plasma optical emission spectrometry, As by hydride-generation atomic absorption spectrometry and Mg and Zn by means of flame furnace atomic absorption spectrometry.

Setting

All samples were provided by the Oncological Centre of Antofagasta Regional Hospital (Region of Antofagasta, Chile).

Participants

Ninety 24-h urine samples from cancer patients after the infusion of Pt-base drugs and 10 24-h urine samples from cancer patients not treated with metal-base drugs.

Main outcome measures

Concentrations of Pt, Se, As, Zn and Mg coming from 24-h urine samples.

Results

Pt excreted was not significantly different between patients with lung and other cancers treated with cisplatin. The excretion of Mg, Zn and Se was greater than As. Then, Pt favours the excretion of essential elements. For lung and other types of cancers treated with drugs without Pt, excretion of Mg, Zn and Se was also greater than that of As, suggesting antagonism Mg-Zn-Se–anti-cancer drug relationship.

Conclusions

The amounts of Mg, Zn and Se excreted were greater than for As either with or without Pt-containing drugs, suggesting antagonist Mg-Zn-Se–anti-cancer drug relationships. The excretion of As, Mg, Zn and Se is induced by Pt. Knowledge obtained can contribute to understanding the arsenic cancer mechanism and the As-Mg-Zn-Se-Pt inter-element association for lung cancer and other types of cancer.

Protective Effects of Selenium, Vitamin E, and Purple Carrot Anthocyanins on D-Galactose-Induced Oxidative Damage in Blood, Liver, Heart and Kidney Rats

The present study was performed to investigate the protective effects of selenium (Se), vitamin E (Vit E) and anthocyanins from purple carrots and their combination against the oxidative stress induced by D-galactose in rats. A total of 80 male rats were equally divided into 11 groups, one of which acted as control (I) just receiving intraperitoneal injections of physiological saline. The remaining ten groups (II-XI) were intraperitoneally injected with D-galactose at a dose of 400 mg kg(-1) body weight (BW) per day for 42 consecutive days. Rats in groups III-XI were treated with antioxidants via gavage per day as follows: group III: Se-methylselenocysteine (SeMSC), IV: Se as sodium selenite (Na2SeO3), V: Se-enriched yeast (SeY), VI: Vit E as α-tocopherol acetate, VII: anthocyanin from purple carrots (APC), VIII: APC + Vit E, IX: SeMSC + APC+ Vit E, X: Na2SeO3 + APC + Vit E, XI: SeY + Ant + Vit E. The results showed that the rats treated with antioxidants (III-XI) showed significant decreases in the levels of malondialdehyde (MDA) and carbonyl protein (PCO) compared with the D-galactose-treated group (II) in the heart, liver, kidneys, and blood. Moreover, there were significant increases in the activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), glutathione (GSH) concentration, and total antioxidant capacity (T-AOC) in the heart, liver, kidneys, and blood of antioxidant-treated animals (III-XI) than those in control group (I). In addition, the combined treatments of two or three antioxidants showed greater antioxidant activities than those of individual treatments, suggesting the synergistic antioxidant effects of Se, Vit E, and APC. In conclusion, all the antioxidants exhibited protective effects against D-galactose-induced oxidative damage in rats, and these antioxidants showed a synergistic effect.

The Role of Natural Polyphenols in the Prevention and Treatment of Cervical Cancer-An Overview

Cervical cancer represents the second leading cause of death for women worldwide. The importance of the diet and its impact on specific types of neoplasia has been highlighted, focusing again interest in the analysis of dietary phytochemicals. Polyphenols have shown a wide range of cellular effects: they may prevent carcinogens from reaching the targeted sites, support detoxification of reactive molecules, improve the elimination of transformed cells, increase the immune surveillance and the most important factor is that they can influence tumor suppressors and inhibit cellular proliferation, interfering in this way with the steps of carcinogenesis. From the studies reviewed in this paper, it is clear that certain dietary polyphenols hold great potential in the prevention and therapy of cervical cancer, because they interfere in carcinogenesis (in the initiation, development and progression) by modulating the critical processes of cellular proliferation, differentiation, apoptosis, angiogenesis and metastasis. Specifically, polyphenols inhibit the proliferation of HPV cells, through induction of apoptosis, growth arrest, inhibition of DNA synthesis and modulation of signal transduction pathways. The effects of combinations of polyphenols with chemotherapy and radiotherapy used in the treatment of cervical cancer showed results in the resistance of cervical tumor cells to chemo- and radiotherapy, one of the main problems in the treatment of cervical neoplasia that can lead to failure of the treatment because of the decreased efficiency of the therapy.

3,3'-OH curcumin causes apoptosis in HepG2 cells through ROS-mediated pathway

In this paper, we synthesized a series of curcumin analogs and evaluated their cytotoxicity against HepG2 cells. The results exhibited that the hydroxyl group at 3,3'-position play an essential role in enhancing their anti-proliferation activity. More importantly, 3,3'-hydroxy curcumin (1b) caused apoptosis in HepG2 cells with the ROS generation, which may be mainly composed of hydroxyl radicals (HO) and H2O2. The more cytotoxic activity and ROS-generating ability of 1b may be due to the more stable in (RPMI)-1640 medium and more massive uptake than curcumin. Then the generation of ROS can disrupt the intracellular redox balance, induce lipid peroxidation, cause the collapse of the mitochondrial membrane potential and ultimately lead to apoptosis. The results not only suggest that 3,3'-hydroxy curcumin (1b) may cause HepG2 cells apoptosis through ROS-mediated pathway, but also offer an important information for design of curcumin analog.

Augmentation of oxidative stress-induced apoptosis in MCF7 cells by ascorbate-tamoxifen and/or ascorbate-juglone treatments

Since reactive oxygen species (ROS) play diverse roles in cancer, modulating the redox status of cancerous cells seems to be a promising therapeutic approach. Oxidant-targeted therapy appears logical for intervention with the acquired adaptive response to oxidative stress in cancer. In this study, we investigated the cytotoxic effects of juglone (J) and tamoxifen (T) and also the combination of each with ascorbate (A): tamoxifen/ascorbate (TA) and/or juglone/ascorbate (JA) on MCF7 cancerous cells. The results revealed that the growth inhibitory effects of juglone and tamoxifen were each associated with enhanced levels of ROS production and lipid peroxidation. These effects were markedly intensified in tamoxifen/ascorbate and juglone/ascorbate co-treatments. On the other hand, the intracellular anti-oxidant components such as reduced glutathione (GSH), catalase, superoxide dismutase (SOD), and glutathione peroxidase significantly declined in cells subjected to combination treatments compared to that in cells exposed solely to tamoxifen, juglone, and the untreated control cells. In addition, ascorbate association induced more apoptotic and necrotic or necrotic-like cell death than cells treated with each drug alone. These results were further confirmed by comparing the Bax/Bcl2 ratio in combination-treated cells. Additionally, ascorbate was able to potentiate the cytotoxic effects of combination therapy via activation of ROS-responsive factors including Foxo family members.

Antioxidant Effects of Herbal Tea Leaves from Yacon (Smallanthus sonchifolius) on Multiple Free Radical and Reducing Power Assays, Especially on Different Superoxide Anion Radical Generation Systems

Yacon (Smallanthus sonchifolius), a native Andean plant, has been cultivated as a crop and locally used as a traditional folk medicine for the people suffering from diabetes and digestive/renal disorders. However, the medicinal properties of this plant and its processed foods have not been completely established. This study investigates the potent antioxidative effects of herbal tea leaves from yacon in different free radical models and a ferric reducing model. A hot-water extract exhibited the highest yield of total polyphenol and scavenging effect on 1,1-diphenyl-2-picryl hydrazyl (DPPH) radical among four extracts prepared with hot water, methanol, ethanol, and ethylacetate. In addition, a higher reducing power of the hot-water extract was similarly demonstrated among these extracts. Varying concentrations of the hot-water extract resulted in different scavenging activities in four synthetic free radical models: DPPH radical (EC50 28.1 μg/mL), 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) cation radical (EC50 23.7 μg/mL), galvinoxyl radical (EC50 3.06 μg/mL), and chlorpromazine cation radical (EC50 475 μg/mL). The yacon tea-leaf extract further demonstrated superoxide anion (O2(-)) radical scavenging effects in the phenazine methosulfate-NADH-nitroblue tetrazolium (EC50 64.5 μg/mL) and xanthine oxidase assay systems (EC50 20.7 μg/mL). Subsequently, incubating human neutrophilic cells in the presence of the tea-leaf extract could suppress the cellular O2(-) radical generation (IC50 65.7 μg/mL) in a phorbol 12-myristate 13-acetate-activated cell model. These results support yacon tea leaves may be a good source of natural antioxidants for preventing O2(-) radical-mediated disorders.

PRACTICAL APPLICATION

Yacon has been considered to be a potent alternative food source for patients who require a dietary cure in regional area, while the leaf part has been provided and consumed as an herbal tea in local markets. We demonstrated here potent antioxidative effects of the tea leaves from yacon in different free radical assays, reducing power assay, and cellular superoxide anion radical generation assay. Results support yacon tea leaves may be a good source of natural antioxidants for preventing O2(-) radical-mediated disorders.

Insights into the importance for designing curcumin-inspired anticancer agents by a prooxidant strategy: The case of diarylpentanoids

Developing anticancer agents by a prooxidant strategy has attracted increasing attention in recent years, although it is not conventional in medicinal chemistry and is completely opposite to antioxidant therapy. In this work, a panel of diarylpentanoids as the curcumin mono-carbonyl analogs were designed and synthesized, and their cytotoxic and proapoptotic mechanisms against human lung cancer A549 cells were investigated at the frontiers of chemistry and biology. It was found that compared with curcumin, the compounds (A1, B1, and C1) bearing two ortho substituents on the aromatic rings, especially A1, exhibit significantly increased cytotoxic and proapoptotic activities through a Michael acceptor unit-dependent prooxidant-mediated mechanism. The prooxidative ability is governed not only by their electrophilicity but also by their geometry, cellular uptake and metabolic stability, and TrxR-inhibitory activity. Mechanistic investigation reveals that the compound A1 could effectively and irreversibly modify the TrxR by virtue of the above optimal biochemical parameters, and convert this antioxidant enzyme into a reactive oxygen species (ROS) promoter, resulting in a burst of the intracellular ROS including H2O2 and O2(-)•. The ROS generation is associated with falling apart in the redox buffering system, and subsequently induces increases in Ca(2+) influx and oxidative stress, collapse of mitochondrial membrane potential, and activation of caspase-9 and caspase-3, ultimately leading to cell apoptosis. This work highlights the feasibility in designing curcumin-inspired anticancer agents by a prooxidant strategy, and gives us useful information on how to design them.

Synergistic effect of Se-methylselenocysteine and vitamin E in ameliorating the acute ethanol-induced oxidative damage in rat

The present study was conduced to investigate the synergistic effects of combined treatments with Se-methylselenocysteine (SeMSC) and vitamin E (Vit E) in reversing oxidative stress induced by ethanol in serum and different tissues of rats. Sixty female rats were randomly divided into six groups for 30 days' consecutive pretreatments as followed: control (I), physiological saline (II), 2.8μgkg(-1) Se as SeMSC (III), 2.8μgkg(-1) Se as sodium selenite (Na2SeO3, IV), 5mgkg(-1) α-tocopherol as α-tocopherol acetate (Vit E, V), 5mgkg(-1) α-tocopherol as α-tocopherol acetate and 2.8μgkg(-1) Se as SeMSC (VI). All animals in groups II-VI were treated by ethanol treatment to cause oxidative stress. After 6h of ethanol treatment, the activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), the contents of total antioxidant capacity (T-AOC), malondialdehyde (MDA), glutathione (GSH) and carbonyl protein (CP) in the serum, liver, heart and kidney were measured. The result showed that the individual SeSMC, Na2SeO3 and vitamin E could effectively increase the SOD, T-AOC, GSH-Px and GSH contents as well as significantly decrease the MDA and CP concentrations in the tissues of ethanol-induced rats. At the same dose on different forms of Se, SeMSC showed greater antioxidant activity than Na2SeO3. Moreover, group VI (SeMSC and α-tocopherol acetate) showed much better antioxidant activity than individual group III (SeMSC) and V (α-tocopherol acetate) due to the synergistic effect.

Honokiol inhibits lung tumorigenesis through inhibition of mitochondrial function

Honokiol is an important bioactive compound found in the bark of Magnolia tree. It is a nonadipogenic PPARγ agonist and capable of inhibiting the growth of a variety of tumor types both in vitro and in xenograft models. However, to fully appreciate the potential chemopreventive activity of honokiol, a less artificial model system is required. To that end, this study examined the chemopreventive efficacy of honokiol in an initiation model of lung squamous cell carcinoma (SCC). This model system uses the carcinogen N-nitroso-trischloroethylurea (NTCU), which is applied topically, reliably triggering the development of SCC within 24 to 26 weeks. Administration of honokiol significantly reduced the percentage of bronchial that exhibit abnormal lung SCC histology from 24.4% bronchial in control to 11.0% bronchial in honokiol-treated group (P = 0.01) while protecting normal bronchial histology (present in 20.5% of bronchial in control group and 38.5% of bronchial in honokiol-treated group. P = 0.004). P63 staining at the SCC site confirmed the lung SCCs phenotype. In vitro studies revealed that honokiol inhibited lung SCC cells proliferation, arrested cells at the G1-S cell-cycle checkpoint, while also leading to increased apoptosis. Our study showed that interfering with mitochondrial respiration is a novel mechanism by which honokiol changed redox status in the mitochondria, triggered apoptosis, and finally leads to the inhibition of lung SCC. This novel mechanism of targeting mitochondrial suggests honokiol as a potential lung SCC chemopreventive agent.

The antioxidant activity of soursop decreases the expression of a member of the NADPH oxidase family

Cellular oxidative stress produced by an increase in free radicals is one of the factors that promote the development of chronic degenerative diseases; therefore, consuming natural antioxidants helps minimize their negative effects. This study evaluated the cytotoxicity of the soursop extract (Annona muricata), its cytoprotective capacity against oxidative stress induced by hydrogen peroxide, the inhibitory potential of reactive oxygen species (ROS), the molecular mechanism of its antioxidant action, and its capacity to repair cellular damage in the fibroblast cell line. The soursop extract proved not to be cytotoxic in fibroblast cultures and showed cytoprotective capacity against hydrogen peroxide-induced stress; in cell culture it reduced the generation of ROS significantly by inhibiting a sub-unit of the NADPH oxidase enzyme (p47phox). The soursop extract can prevent damage caused by cellular oxidants.

Elements of margin of safety, toxicity and action of sodium selenite in a lipopolysaccharide rat model

PROJECT

Both septic shock and sodium selenite (Na2SeO3) lead to multiple organ failure through oxidation. Na2SeO3 has direct oxidant effects above the nutritional level and indirect anti-oxidant properties. In a lipopolysaccharide (LPS) rat model we assessed margin of safety, toxicity and beneficial effect of pentahydrate Na2SeO3 (5H2O·Na2SeO3) at oxidant doses.

PROCEDURE

In a three-step study on 204 rats we: (i) observed toxic effects of Na2SeO3 injected intraperitoneously (IP) and determined its Minimum Dose Without Toxic effect (MDWT) 0.25-0.35 mg/kg selenium (Se) content; (ii) injected IP LPS at 70% lethal dose (LD) followed, or not, one hour later by IP Na2SeO3 at MDWT and (iii) by doses>MDWT. At 48 h, in survivors, we measured plasma creatinine, lactate, aspartate and alanine aminotransferase (AST, ALT), nitric oxide (NO) and Se concentrations.

RESULTS

(i) Na2SeO3 alone did not increase NO and lactate. Encephalopathy appeared at 1mg Se/kg. Creatinine increased at 1-1.75 mg Se/kg, AST, ALT at 3-4.5 mg Se/kg, and the minimum LD was 3 mg Se/kg. (ii) Mortality after LPS was 37/50 (74%, [62-86%]) vs. 20/30 (67%, [50-84%]) when followed by Na2SeO3 at MDWT (p=0.483) with a decreased in NO (-31%, p=0.038) a trend for lactate decrease (-19%, p=0.068) and an increased Se in plasma of survivals. (iii) All rats died at doses ≥0.6 mg/kg (p<0.001).

CONCLUSION

Mechanisms of LPS and Na2SeO3 toxicity differ (i.e. NO, lactate). In septic shock 5H2O·Na2SeO3 toxicity increased, margin of safety decrease, but IP administration of dose considered as oxidant of 5H2O·Na2SeO3 showed beneficial effects.

Adlay ( yì yĭ; "soft-shelled job's tears"; the seeds of Coix lachryma-jobi L. var. ma-yuen Stapf) is a Potential Cancer Chemopreventive Agent toward Multistage Carcinogenesis Processes

Adlay ( yì yĭ "soft-shelled job's tears", the seeds of Coix lachryma-jobi L. var. ma-yuen Stapf) is a grass crop that has long been used in traditional Chinese medicine (TCM) and as a nourishing food in China for the treatment of warts, chapped skin, rheumatism, neuralgia, inflammatory, and neoplastic diseases. In addition, adlay also has been said to have stomachic, diuretic, antipholgistic, anodynic, and antispasmodic effects. Carcinogenesis is a multistage process that begins with exposure of viruses or chemicals that are found in the environment. Chemoprevention refers to the use of natural or synthetic, non-toxic chemical substances to reverse, repress, or prevent carcinogenesis. In this review, we summarize recent research attempting to study the chemopreventive blocking and suppressing potential of adlay and its active components in scavenging electrophiles and reactive oxygen species, antimutagenicity, enhancing Nrf2-mediated detoxification and antioxidant effect, altering carcinogen metabolism, suppressing proliferation, decreasing inflammation, and enhancing antitumor immunity. In addition, several active components with diverse chemopreventive properties have been also mentioned in this review article.

Selenium suppresses leukemia through the action of endogenous eicosanoids

Eradicating cancer stem-like cells (CSC) may be essential to fully eradicate cancer. Metabolic changes in CSC could hold a key to their targeting. Here, we report that the dietary micronutrient selenium can trigger apoptosis of CSC derived from chronic or acute myelogenous leukemias when administered at supraphysiologic but nontoxic doses. In leukemia CSC, selenium treatment activated ATM-p53-dependent apoptosis accompanied by increased intracellular levels of reactive oxygen species. Importantly, the same treatment did not trigger apoptosis in hematopoietic stem cells. Serial transplantation studies with BCR-ABL-expressing CSC revealed that the selenium status in mice was a key determinant of CSC survival. Selenium action relied upon the endogenous production of the cyclooxygenase-derived prostaglandins Δ(12)-PGJ2 and 15d-PGJ2. Accordingly, nonsteroidal anti-inflammatory drugs and NADPH oxidase inhibitors abrogated the ability of selenium to trigger apoptosis in leukemia CSC. Our results reveal how selenium-dependent modulation of arachidonic acid metabolism can be directed to trigger apoptosis of primary human and murine CSC in leukemia.

A comparative study on the antioxidant activity of commonly used South asian herbs

The antioxidant activities of curry leaves, fenugreek seeds, Indian malabar leaves, red silk cotton tree leaves, cowitch leaves, holyfruit tree leaves, and black mustard seeds were compared. Their effects on reactive oxygen species (ROS) and superoxide dismutase (SOD) activity were investigated. The Oxygen Radical Absorbance Capacity (ORAC) assay determined the antioxidant potential of the extracts, while the ROS scavenging ability was explored in hyperglycemia-induced human umbilical vein endothelial cells (HUVECs). The SOD assay determined if the extracts stimulated the enzyme activity in the HUVECs. Curry leaf and fenugreek extracts had high ORAC values and superior free radical scavenging abilities compared with the rest of the extracts. The curry leaf extract had also increased the SOD activity. Fenugreek extract had not increased the SOD activity of the HUVECs. Thus, the two herbs displayed two distinct pathways of action for scavenging of ROS.

Phytoagents for cancer management: regulation of nucleic acid oxidation, ROS, and related mechanisms

Accumulation of oxidized nucleic acids causes genomic instability leading to senescence, apoptosis, and tumorigenesis. Phytoagents are known to reduce the risk of cancer development; whether such effects are through regulating the extent of nucleic acid oxidation remains unclear. Here, we outlined the role of reactive oxygen species in nucleic acid oxidation as a driving force in cancer progression. The consequential relationship between genome instability and cancer progression highlights the importance of modulation of cellular redox level in cancer management. Current epidemiological and experimental evidence demonstrate the effects and modes of action of phytoagents in nucleic acid oxidation and provide rationales for the use of phytoagents as chemopreventive or therapeutic agents. Vitamins and various phytoagents antagonize carcinogen-triggered oxidative stress by scavenging free radicals and/or activating endogenous defence systems such as Nrf2-regulated antioxidant genes or pathways. Moreover, metal ion chelation by phytoagents helps to attenuate oxidative DNA damage caused by transition metal ions. Besides, the prooxidant effects of some phytoagents pose selective cytotoxicity on cancer cells and shed light on a new strategy of cancer therapy. The “double-edged sword” role of phytoagents as redox regulators in nucleic acid oxidation and their possible roles in cancer prevention or therapy are discussed in this review.

Anticancer activity of Zea mays leaf extracts on oxidative stress-induced Hep2 cells

Cancer is one of the leading causes of death in humans. It is believed that plants can provide potential bioactive compounds for the development of "new leads" to combat cancer and other diseases. The present study focuses on the ability of the different extracts (aqueous, methanol, and chloroform) of the leaves of Zea mays in influencing the process of apoptosis induced by hydrogen peroxide (H2O2) in Hep2 (laryngeal carcinoma) cells. Various apoptosis-related parameters, such as cell viability, morphological changes, nuclear changes, and apoptotic index were characterized. sulforhodamine B and MTT assays were used to quantify the extent of cell death in the group exposed to H2O2, plant extracts, and their combination. Treatment with H2O2 caused cytotoxicity in cancer cells. The administration of leaf extract also caused an increase in the death of cancer cells. Oxidatively stressed cancer cells co-treated with all the Z. mays leaf extracts (except the chloroform extract) demonstrated cytotoxicity on a par with the H2O2-treated groups. This indicated that the aqueous and methanol leaf extracts did not influence the cytotoxic action of H2O2 in the cancer cells. Thus, various apoptosis-related events in Hep2 cells exposed to leaf extract throw light on the potential anticancer activity of the Z. mays leaves. The maximum activity was exerted by the methanolic extract followed by the aqueous and chloroform extracts.

Cell survival and apoptosis signaling as therapeutic target for cancer: marine bioactive compounds

Inhibition of apoptosis leads to activation of cell survival factors (e.g., AKT) causes continuous cell proliferation in cancer. Apoptosis, the major form of cellular suicide, is central to various physiological processes and the maintenance of homeostasis in multicellular organisms. A number of discoveries have clarified the molecular mechanism of apoptosis, thus clarifying the link between apoptosis and cell survival factors, which has a therapeutic outcome. Induction of apoptosis and inhibition of cell survival by anticancer agents has been shown to correlate with tumor response. Cellular damage induces growth arrest and tumor suppression by inducing apoptosis, necrosis and senescence; the mechanism of cell death depends on the magnitude of DNA damage following exposure to various anticancer agents. Apoptosis is mainly regulated by cell survival and proliferating signaling molecules. As a new therapeutic strategy, alternative types of cell death might be exploited to control and eradicate cancer cells. This review discusses the signaling of apoptosis and cell survival, as well as the potential contribution of marine bioactive compounds, suggesting that new therapeutic strategies might follow.