Plants vs. cancer: a review on natural phytochemicals in preventing and treating cancers and their druggability

Natural Products for the Management and Prevention of Breast Cancer

Among all types of cancer, breast cancer is one of the most challenging diseases, which is responsible for a large number of cancer related deaths. Hormonal therapy, surgery, chemotherapy, and radiotherapy have been used as treatment of breast cancer, for a very long time. Due to severe side effects and multidrug resistance, these treatment approaches become increasingly ineffective. However, adoption of complementary treatment approach can be a big solution for this situation, as it is evident that compounds derived from natural source have a great deal of anticancer activity. Natural compounds can fight against aggressiveness of breast cancer, inhibit cancerous cell proliferation, and modulate cancer related pathways. A large number of research works are now focusing on the natural and dietary compounds and trying to find out new and more effective treatment strategies for the breast cancer patients. In this review, we discussed some significant natural chemical compounds with their mechanisms of actions, which can be very effective against the breast cancer and can be more potent by their proper modifications and further clinical research. Future research focusing on the natural anti-breast-cancer agents can open a new horizon in breast cancer treatment, which will play a great role in enhancing the survival rate of breast cancer patients.

Citral induced apoptosis in MDA-MB-231 spheroid cells

Background

Breast cancer remains a leading cause of death in women worldwide. Although breast cancer therapies have greatly advanced in recent years, many patients still develop tumour recurrence and metastasis, and eventually succumb to the disease due to chemoresistance. Citral has been reported to show cytotoxic effect on various cancer cell lines. However, the potential of citral to specifically target the drug resistant breast cancer cells has not yet been tested, which was the focus of our current study.

Methods

The cytotoxic activity of citral was first tested on MDA-MB-231 cells in vitro by MTT assay. Subsequently, spheroids of MDA-MB-231 breast cancer cells were developed and treated with citral at different concentrations. Doxorubicin, cisplatin and tamoxifen were used as positive controls to evaluate the drug resistance phenotype of MDA-MB-231 spheroids. In addition, apoptosis study was performed using AnnexinV/7AAD flowcytometry. Aldefluor assay was also carried out to examine whether citral could inhibit the ALDH-positive population, while the potential mechanism of the effect of citral was carried out by using quantitative real time- PCR followed by western blotting analysis.

Results

Citral was able to inhibit the growth of the MDA-MB-231 spheroids when compared to a monolayer culture of MDA-MB-231 cells at a lower IC₅₀ value. To confirm the inhibition of spheroid self-renewal capacity, the primary spheroids were then cultured to additional passages in the absence of citral. A significant reduction in the number of secondary spheroids were formed, suggesting the reduction of self-renewal capacity of these aldehyde dehydrogenase positive (ALDH⁺) drug resistant spheroids. Moreover, the AnnexinV/7AAD results demonstrated that citral induced both early and late apoptotic changes in a dose-dependent manner compared to the vehicle control. Furthermore, citral treated spheroids showed lower cell renewal capacity compared to the vehicle control spheroids in the mammosphere formation assay. Gene expression studies using quantitative real time PCR and Western blotting assays showed that citral was able to suppress the self-renewal capacity of spheroids and downregulate the Wnt/β-catenin pathway.

Conclusion

The results suggest that citral could be a potential new agent which can eliminate drug-resistant breast cancer cells in a spheroid model via inducing apoptosis.

Induction of apoptosis by pinostrobin in human cervical cancer cells: Possible mechanism of action

Pinostrobin (PN) is a naturally occurring dietary bioflavonoid, found in various medicinal herbs/plants. Though anti-cancer potential of many such similar constituents has been demonstrated, critical biochemical targets and exact mechanism for their apoptosis-inducing actions have not been fully elucidated. The present study was aimed to investigate if PN induced apoptosis in cervical cancer cells (HeLa) of human origin. It is demonstrated that PN at increasing dose effectivity reduced the cell viability as well as GSH and NO2- levels. Condensed nuclei with fragmented chromatin and changes in mitochondrial matrix morphology clearly indicated the role of mitochondria in PN induced apoptosis. A marked reduction in mitochondrial membrane potential and increased ROS production after PN treatment showed involvement of free radicals, which in turn further augment ROS levels. PN treatment resulted in DNA damage, which could have been triggered by an increase in ROS levels. Decrease in apoptotic cells in the presence of caspase 3 inhibitor in PN-treated cells suggested that PN induced apoptosis via caspase dependent pathways. Additionally, a significant increase in the expression of proteins of extrinsic (TRAIL R1/DR4, TRAIL R2/DR5, TNF RI/TNFRSF1A, FADD, Fas/TNFRSF6) and intrinsic pathway (Bad, Bax, HTRA2/Omi, SMAC/Diablo, cytochrome C, Pro-Caspase-3, Cleaved Caspase-3) was observed in the cells exposed to PN. Taken together, these observations suggest that PN efficiently induces apoptosis through ROS mediated extrinsic and intrinsic dependent signaling pathways, as well as ROS mediated mitochondrial damage in HeLa cells.

Advances in computational metabolomics and databases deepen the understanding of metabolisms

Mass spectrometry (MS)-based metabolomics is the popular platform for metabolome analyses. Computational techniques for the processing of MS raw data, for example, feature detection, peak alignment, and the exclusion of false-positive peaks, have been established. The next stage of untargeted metabolomics would be to decipher the mass fragmentation of small molecules for the global identification of human-, animal-, plant-, and microbiota metabolomes, resulting in a deeper understanding of metabolisms. This review is an update on the latest computational metabolomics including known/expected structure databases, chemical ontology classifications, and mass spectrometry cheminformatics for the interpretation of mass fragmentations and for the elucidation of unknown metabolites. The importance of metabolome 'databases' and 'repositories' is also discussed because novel biological discoveries are often attributable to the accumulation of data, to relational databases, and to their statistics. Lastly, a practical guide for metabolite annotations is presented as the summary of this review.

Enhanced Oral Bioavailability of Curcumin Using a Supersaturatable Self-Microemulsifying System Incorporating a Hydrophilic Polymer; In Vitro and In Vivo Investigations

A supersaturatable self-microemulsifying drug delivery system (S-SMEDDS) with a reduced amount of surfactant and incorporation of a polymer precipitation inhibitor, Eudragit® E PO was developed. The optimized S-SMEDDS formulation (SS-15) consisted of 55% surfactants, 40% oils, and 5% Eudragit® E PO (curcumin at 44.4 mg/g of the formulation). The precipitation profiles from the supersaturation assay revealed that the curcumin S-SMEDDS performed as a better inhibitor of curcumin precipitation in simulated gastric fluid over a 240-min study than the normal curcumin SMEDDS and an aqueous curcumin suspension. In addition, the mean droplet size of the curcumin S-SMEDDS (21.6 ± 0.1 nm) was significantly smaller than the SMEDDS (28.1 ± 0.3 nm). The curcumin S-SMEDDS exhibited a threefold reduction of Caco-2 cell toxicity when compared to the curcumin SMEDDS because of the reduced toxic effect of the surfactant present in the SMEDDS formulation. In addition, the absorptive permeability across the Caco-2 monolayer of curcumin in the S-SMEDDS was significantly higher than for the unformulated curcumin (~ 5-folds). The plasma concentration-time profiles from the oral absorption studies in rats dosed with the curcumin S-SMEDDS showed a 1.22- and 53.14-fold increased absorption of curcumin, compared to the SMEDDS and the aqueous suspension, respectively. The curcumin S-SMEDDS was stable under both intermediate and accelerated conditions after 6 months of storage.

The Role of Secondary Metabolites on Gynecologic Cancer Therapy: Some Pathways and Mechanisms

Gynecologic cancers are among the most common cancers in humans and animals. Treatment success depends on several factors including stage at diagnosis, tumor type, origin and metastasis. Currently, surgery, chemotherapy, and radiotherapy are preferred in the treatment of these cancers. However, many anticarcinogenic drugs can cause severe adverse effects and also the expected response to treatment may not be obtained. In recent studies, the importance of the relationship between cancer and inflammation has been emphasized. Therefore, several phytochemicals that exhibit beneficial bioactive effects towards inflammatory pathways were proven to have anticarcinogenic potential for gynecologic cancer therapy. This review summarizes the role of inflammatory pathways in gynecologic cancers and effective secondary metabolites for cancer therapy.

Phloridzin docosahexaenoate, a novel flavonoid derivative, suppresses growth and induces apoptosis in T-cell acute lymphoblastic leukemia cells

The overall clinical outcome in T-cell acute lymphoblastic leukemia (T-ALL) can be improved by minimizing risk for treatment failure using effective pharmacological adjuvants. Phloridzin (PZ), a flavonoid precursor found in apple peels, was acylated with docosahexaenoic acid (DHA) yielding a novel ester known as phloridzin docosahexaenoate (PZ-DHA). Here, we have studied the cytotoxic effects of PZ-DHA on human leukemia cells using in vitro and in vivo models. The inhibitory effects of PZ-DHA were tested on human Jurkat T-ALL cells in comparison to K562 chronic myeloid leukemia (CML) cells and non-malignant murine T-cells. PZ-DHA, not PZ or DHA alone, reduced cell viability and ATP levels, increased intracellular LDH release, and caused extensive morphological alterations in both Jurkat and K562 cells. PZ-DHA also inhibited cell proliferation, and selectively induced apoptosis in Jurkat and K562 cells while sparing normal murine T-cells. The cytotoxic effects of PZ-DHA on Jurkat cells were associated with caspase activation, DNA fragmentation, and selective down-regulation of STAT3 phosphorylation. PZ-DHA significantly inhibited Jurkat cell proliferation in zebrafish larvae; however, the proliferation of K562 cells was not affected in vivo. We propose that PZ-DHA-induced cytotoxic response is selective towards T-ALL in the presence of a tumor-stromal microenvironment. Prospective studies evaluating the combinatorial effects of PZ-DHA with conventional chemotherapy for T-ALL are underway.

Nanocarrier-mediated delivery of α-mangostin for non-surgical castration of male animals

The overpopulation of abandoned and stray companion animals has become a global crisis. The main purpose of this study was to develop a novel nanomedicine-based antifertility compound for non-surgical castration of male animals. Mangosteen (Garcinia mangostana L) pericarp extract has been shown to exhibit anti-fertility property. α-mangostin (AM)-loaded nanostructured lipid carrier (AM-NLC) was developed to improve male germ cell apoptosis. This study was conducted to investigate physicochemical properties of AM-NLC and determine the biological effects of AM-NLC on spermatogonia cells and testicular explants obtained from castrated testes. AM-NLC was produced through a hot homogenization technique. The negatively charged particle of AM-NLC was nano-sized with a narrow dispersity. AM-NLC exhibited antiproliferative activity towards spermatogonium cells. It induced apoptosis in the cells. In addition, AM-NLC exhibited anti-inflammatory activities in lipopolysaccharide-activated macrophages. Abnormal anatomy of seminiferous tubule was noted following treatment of testicular explant with AM-NLC. This nanomedicine-based sterilant would be a promising platform that may have utility in non-surgical castration of male animals by intra-testicular injection.

Tetrandrine and cancer - An overview on the molecular approach

Tetrandrine has been known in the treatment of tuberculosis, hyperglycemia, negative ionotropic and chronotropic effects on myocardium, malaria, cancer and fever since years together. It has been known that, tetrandrine could modulate multiple signaling molecules such as kinases of cell cycle and rat sarcoma (RAS) pathway along with proteins of tumor suppressor genes, autophagy related, β-catenins, caspases, and death receptors. Moreover, tetrandrine exhibited reversal of drug resistance by modulating P-glyco protein (P-gp) expression levels in different cancers which is an added advantage of this compound compared to other chemotherapy drugs. Though, bioavailability of tetrandrine is a limiting factor, the anticancer activity was observed in animal models without changing any pharmacokinetic parameters. In the present review, role of tetrandrine as kinase inhibitor, inducer of autophagy and caspase pathways and suppressor of RAS mediated cell proliferation were discussed along with inhibition of angiogenesis. It has also been discussed that how tetrandrine potentiate anticancer effect in different types of cancers by modulating multidrug resistance under in vitro and in vivo trials including the available literature on the clinical trials.

Silybin counteracts doxorubicin resistance by inhibiting GLUT1 expression

Despite significant advances in the diagnosis and treatment of cancer, the development of drug resistance still remains one of the principal causes that hampers the effectiveness of the therapy. Emerging evidences support the idea that the dysregulated metabolism could be related to drug resistance. The major goal of this study was to target cancer metabolic pathways using new pharmacological approaches coming from natural sources in order to possibly prevent or overcome this phenomenon. Firstly, the metabolic profile of human colorectal adenocarcinoma cells sensitive (LoVo WT) and resistant to doxorubicin (LoVo DOX) was delineated demonstrating that resistant cells remodel their metabolism toward a glycolytic phenotype. In particular it was observed that doxorubicin-resistant cancer cells exhibit an increased dependency from glucose for their survival, associated with overexpression of the glycolytic pathway. Moreover, both GLUT1 mRNA and protein expression significantly increased in LoVo DOX cells. Given the results about the metabolic profile, silybin, modulator of GLUTs, was selected as potential candidate to overcome doxorubicin resistance and, intriguingly, data revealed not only that silybin is more active in resistant cells than in wild type cells, but also that the combined treatment with doxorubicin and silybin presents a synergistic effect in LoVo DOX cells. Although many unanswered questions still remain about the molecular mechanism of silybin, these data suggest that targeting GLUTs may be a good strategy to restore doxorubicin sensitivity and elude drug resistance.

Interactions of quercetin with receptor tyrosine kinases associated with human lung carcinoma

Lung cancer is a deadly form of cancer with high morbidity and mortality rates. Deregulated receptor tyrosine kinases (RTKs) are frequently associated with the formation and development of lung carcinoma. Quercetin is a major dietary flavonoid that has been shown to induce cell growth inhibition and apoptosis in human lung cancer cell lines. In the current study, four major overexpressed RTKs - EGFR, FGFR1, IGF1R and c-Met - involved in human lung cancer were investigated. Molecular docking was employed to identify the binding orientation and inhibitory potential of quercetin in these RTKs. Quercetin bound to the ATP binding pocket of these kinases exhibited good binding scores and interactions by establishing hydrogen, hydrophobic and π-π interactions with the hinge region and the DFG motif in the activation loop. Thus, quercetin could be further explored as a platform for developing specific or polypharmacological compounds targeting overexpressed RTKs in lung cancer.

Evaluation of Herbal Concoctions Sold at Ga Maja (Limpopo Province) in South Africa and In Vitro Pharmacological Evaluation of Plants Used to Manufacture the Concoctions

The aim of the study was to evaluate the biological activities and safety of commercial herbal concoctions manufactured in Ga Maja (Limpopo province). Microbial contamination was evaluated by spread-plating the concoctions on agar plates. The VITEK 2 instrument was used for identification of the pure cultures. Nutritional content of the concoctions was determined. Thin layer chromatography was used to analyze the chemical constituents of the extracts. The microdilution assay and bioautography were used to evaluate antimicrobial activity against selected microorganisms. Sodium, potassium, and zinc were elements most abundant in the concoctions. Phytochemical screening revealed the presence of various phytoconstituents. Acetone extracts of Hypoxis hemerocallidea and Kirkia wilmsii extracts had antioxidant activity. The minimum inhibitory concentrations values against test bacteria ranged between 0.02 and 0.63 mg/mL. Further studies are required to isolate bioactive compounds and evaluate their cytotoxicity. Caution in the consumption of the herbal mixtures should be adhered to.

Brassica-Derived Plant Bioactives as Modulators of Chemopreventive and Inflammatory Signaling Pathways

A high consumption of vegetables belonging to the Brassicaceae family has been related to a lower incidence of chronic diseases including different kinds of cancer. These beneficial effects of, e.g., broccoli, cabbage or rocket (arugula) intake have been mainly dedicated to the sulfur-containing glucosinolates (GLSs)-secondary plant compounds nearly exclusively present in Brassicaceae-and in particular to their bioactive breakdown products including isothiocyanates (ITCs). Overall, the current literature indicate that selected Brassica-derived ITCs exhibit health-promoting effects in vitro, as well as in laboratory mice in vivo. Some studies suggest anti-carcinogenic and anti-inflammatory properties for ITCs which may be communicated through an activation of the redox-sensitive transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2) that controls the expression of antioxidant and phase II enzymes. Furthermore, it has been shown that ITCs are able to significantly ameliorate a severe inflammatory phenotype in colitic mice in vivo. As there are studies available suggesting an epigenetic mode of action for Brassica-derived phytochemicals, the conduction of further studies would be recommendable to investigate if the beneficial effects of these compounds also persist during an irregular consumption pattern.

Nutrigenomics in cancer: Revisiting the effects of natural compounds

Nutrigenomics effects have an important role in the manipulation of dietary components for human benefit, particularly in cancer prevention or treatment. The impact of dietary components, including phytochemicals, is largely studied by nutrigenomics, looking at the gene expression and molecular mechanisms interacting with bioactive compounds and nutrients, based on new 'omics' technologies. The high number of preclinical studies proves the relevant role of nutrigenomics in cancer management. By deciphering the network of nutrient-gene connections associated with cancer, relevant data will be transposed as therapeutic interventions for this devastating pathology and for fulfilling the concept of personalized nutrition. All these are presented under the nutrigenomics canopy for a better comprehension of the relation between ingested phytochemicals and chemoprevention or chemotherapy. The profits from the nutrigenomics progress, with a particular focus on the coding and noncoding genes related to the exposure of natural compounds need to be validated. A precise attention receives the evaluation of the role of natural compounds in tandem with conventional therapy using genomic approaches, with emphasis on the capacity to inhibit drug resistance mechanisms. All these relevant nutrigenomics aspects are summarized in the present review paper. It is concluded that further nutrigenomics studies are required to improve our understanding related to the complex mechanisms of action of the natural compounds and for their appropriate application as gears in cancer therapy.

Dietary Intervention by Phytochemicals and Their Role in Modulating Coding and Non-Coding Genes in Cancer

Phytochemicals are natural compounds synthesized as secondary metabolites in plants, representing an important source of molecules with a wide range of therapeutic applications. These natural agents are important regulators of key pathological processes/conditions, including cancer, as they are able to modulate the expression of coding and non-coding transcripts with an oncogenic or tumour suppressor role. These natural agents are currently exploited for the development of therapeutic strategies alone or in tandem with conventional treatments for cancer. The aim of this paper is to review the recent studies regarding the role of these natural phytochemicals in different processes related to cancer inhibition, including apoptosis activation, angiogenesis and metastasis suppression. From the large palette of phytochemicals we selected epigallocatechin gallate (EGCG), caffeic acid phenethyl ester (CAPE), genistein, morin and kaempferol, due to their increased activity in modulating multiple coding and non-coding genes, targeting the main hallmarks of cancer.

Enterolactone Induces G1-phase Cell Cycle Arrest in Nonsmall Cell Lung Cancer Cells by Downregulating Cyclins and Cyclin-dependent Kinases

Flaxseed is a rich source of the plant lignan secoisolariciresinol diglucoside (SDG), which is metabolized into mammalian lignans enterodiol (ED) and enterolactone (EL) in the digestive tract. The anticancer properties of these lignans have been demonstrated for various cancer types, but have not been studied for lung cancer. In this study, we investigated the anticancer effects of EL for several nonsmall cell lung cancer (NSCLC) cell lines of various genetic backgrounds. EL inhibited the growth of A549, H441, and H520 lung cancer cells in concentration- and time-dependent manners. The antiproliferative effects of EL for lung cancer cells were not due to enhanced cell death, but rather due to G1-phase cell cycle arrest. Molecular studies revealed that EL decreased mRNA or protein expression levels of the G1-phase promoters cyclin D1, cyclin E, cyclin-dependent kinases (CDK)-2, -4, and -6, and p-cdc25A; decreased phosphorylated retinoblastoma (p-pRb) protein levels; and simultaneously increased levels of p21WAF1/CIP1, a negative regulator of the G1 phase. The results suggest that EL inhibits the growth of NSCLC cell lines by downregulating G1-phase cyclins and CDKs, and upregulating p21WAF1/CIP1, which leads to G1-phase cell cycle arrest. Therefore, EL may hold promise as an adjuvant treatment for lung cancer therapy.

In vitro anticancer properties of selected Eucalyptus species

In spite of the recent advancements in oncology, the overall survival rate for pancreatic cancer has not improved over the last five decades. Eucalypts have been linked with cytotoxic and anticancer properties in various studies; however, there is very little scientific evidence that supports the direct role of eucalypts in the treatment of pancreatic cancer. This study assessed the anticancer properties of aqueous and ethanolic extracts of four Eucalyptus species using an MTT assay. The most promising extracts were further evaluated using a CCK-8 assay. Apoptotic studies were performed using a caspase 3/7 assay in MIA PaCa-2 cells. The aqueous extract of Eucalyptus microcorys leaf and the ethanolic extract of Eucalyptus microcorys fruit inhibited the growth of glioblastoma, neuroblastoma, lung and pancreatic cancer cells by more than 80% at 100 μg/mL. The E. microcorys and Eucalyptus saligna extracts showed lower GI₅₀ values than the ethanolic Eucalyptus robusta extract in MIA PaCa-2 cells. Aqueous E. microcorys leaf and fruit extracts at 100 μg/mL exerted significantly higher cell growth inhibition in MIA PaCa-2 cells than other extracts (p < 0.05). Statistically similar IC₅₀ values (p > 0.05) were observed in aqueous E. microcorys leaf (86.05 ± 4.75 μg/mL) and fruit (64.66 ± 15.97 μg/mL) and ethanolic E. microcorys leaf (79.30 ± 29.45 μg/mL) extracts in MIA PaCa-2 cells using the CCK-8 assay. Caspase 3/7-mediated apoptosis and morphological changes of cells were also witnessed in MIA PaCa-2 cells after 24 h of treatment with the extracts. This study highlighted the significance of E. microcorys as an important source of phytochemicals with efficacy against pancreatic cancer cells. Further studies are warranted to purify and structurally identify individual compounds and elucidate their mechanisms of action for the development of more potent and specific chemotherapeutic agents for pancreatic cancer.

Balsamin induces apoptosis in breast cancer cells via DNA fragmentation and cell cycle arrest

Breast cancer is the second most common cancer causing death worldwide with metastasis and disease relapse being the major drawbacks in current treatments. Therefore, development of novel drugs is needed. Balsamin, a 28 kDa Type I ribosome-inactivating protein, is rich in the seeds of Momordica balsamina. In this study, the molecular mechanism and the possible effects of balsamin on the two key hallmarks of cancer were investigated. Firstly, the induction of apoptosis in human breast cancer MCF-7 and BT549 cells showed that balsamin-induced apoptosis involved increases in caspase-3 and caspase-8 activity, upregulation of Bax, Bid, and Bad, and downregulation of BCL-2 and BCL-XL. Furthermore, balsamin inhibited the proliferation of breast cancer cells in a dose-dependent manner with IC₅₀ values of 24.53 and 32.79 µg/ml for MCF-7 and BT549 cells, respectively. Moreover, flow cytometric analysis revealed that balsamin induced S-/G-phase cell cycle arrest. Our studies show that balsamin has anti-tumor activity and could be used as a neutraceutical for the treatment of breast cancer.

Targeting the mercapturic acid pathway and vicenin-2 for prevention of prostate cancer

Prostate cancer (CaP) is often androgen-sensitive malignancy and regresses upon inhibition of androgen signaling. However, CaP, nearly always develops androgen resistance and progresses to aggressive and lethal androgen-independent CaP, which lacks satisfactory therapy. For metastatic CaP, patients are often treated with Taxotere (docetaxel), a cytoskeleton-targeted chemotherapy drug, that provides transient palliative benefit but to which patients rapidly develop drug-resistance. Combination chemotherapy may be used instead, but is more toxic and adds little clinically relevant benefit over docetaxel. Therefore, novel strategies to enhance docetaxel efficacy are needed to effectively treat patients with metastatic CaP. The mercapturic acid pathway, which metabolizes genotoxic and pro-apoptotic toxins, is over-expressed in CaP and plays an important role in carcinogenesis, metastasis and therapy-resistance of CaP. Vicenin-2, a flavonoid derived from Tulsi (holy basil) as an active compound, inhibits the growth of CaP and increases the anti-tumor activity of docetaxel in-vitro and in-vivo. Taken together, the combination of vicenin-2 and docetaxel could be highly effective in the treatment of advanced and metastatic CaP due to their multi-targeting anti-tumor potential.

Cross-Linked Polymer-Stabilized Nanocomposites for the Treatment of Bacterial Biofilms

Infections caused by bacterial biofilms are an emerging threat to human health. Conventional antibiotic therapies are ineffective against biofilms due to poor penetration of the extracellular polymeric substance secreted by colonized bacteria coupled with the rapidly growing number of antibiotic-resistant strains. Essential oils are promising natural antimicrobial agents; however, poor solubility in biological conditions limits their applications against bacteria in both dispersed (planktonic) and biofilm settings. We report here an oil-in-water cross-linked polymeric nanocomposite (∼250 nm) incorporating carvacrol oil that penetrates and eradicates multidrug-resistant (MDR) biofilms. The therapeutic potential of these materials against challenging wound biofilm infections was demonstrated through specific killing of bacteria in a mammalian cell-biofilm coculture wound model.

Ameliorative effects of gallic acid, quercetin and limonene on urethane-induced genotoxicity and oxidative stress in Drosophila melanogaster

The main objective of our present work was to ascertain the efficacy of Drosophila melanogaster model for assessing antigenotoxic and antioxidant effects of dietary phytochemicals gallic acid (GA), quercetin (QC) and limonene (Lim) against urethane (URE), a genotoxic environmental carcinogen. Oregon-K (ORK) adult male flies were fed GA, QC and Lim in combination with URE (20 mM) in 10% sucrose for 72 h. Third instar larvae were fed instant medium containing the above phytochemicals and URE for 24 h. Sex-linked recessive lethal (SLRL) test and assays for estimating glutathione content (GSH), glutathione S-transferase (GST), catalase (CAT), superoxide dismutase (SOD) and lipid peroxidation (MDA content) were performed. Adult feeding experiments demonstrated that co-treatment of flies with URE and the test phytochemicals has significantly decreased the frequencies of SLRL mutations in all the germ cell stages when compared to that with URE alone. Larval feeding experiments also showed a similar pattern. The above results correlate well with antioxidative potentials of the test agents where we observed the elevated enzymatic levels with a significant reduction in MDA level in Drosophila larvae. The results further suggest that the dietary phytochemicals have an antioxidant and antimutagenic property which can be assessed using D. melanogaster.

Dietary phytochemical PEITC restricts tumor development via modulation of epigenetic writers and erasers

Dietary intake of bioactive phytochemicals including the cruciferous vegetable derivative phenethyl isothiocyanate (PEITC) can reduce risk of human cancers, but possible epigenetic mechanisms of these effects are yet unknown. We therefore sought to identify the molecular basis of PEITC-mediated epigenetic tumor restriction. Colon cancer cells treated with low-dose PEITC for >1 month exhibited stable alterations in expression profile of epigenetic writers/erasers and chromatin-binding of histone deacetylases (HDACs) and Polycomb-group (PcG) proteins. Sustained PEITC exposure not only blocked HDAC binding to euchromatin but was also associated with hypomethylation of PcG target genes that are typically hypermethylated in cancer. Furthermore, PEITC treatment induced expression of pro-apoptotic genes in tumor cells, which was partially reversed by overexpression of PcG member BMI-1, suggesting opposing roles for PEITC and PcG proteins in control of tumor progression. These data demonstrate that PEITC regulates chromatin binding of key epigenetic writers/erasers and PcG complexes to restrict tumor development.

Anti-hepatocarcinogenic and Anti-oxidant Effects of Mangrove Plant Scyphiphora hydrophyllacea

CONTEXT

Scyphiphora hydrophyllacea is a shrub mangrove plant of the family Rubiaceae and not yet been studied for anti-hepatocarcinogenic effects.

OBJECTIVES

We investigated possible in vitro anti-hepatocarcinogenic and antioxidant properties of S. hydrophyllacea.

MATERIALS AND METHODS

Dried leaves of S. hydrophyllacea were sequentially extracted into hexane, chloroform, ethyl acetate, and methanol and tested for cytotoxicity on HepG2 cells by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) and sulforhodamine B assays, and for antioxidant activities by the free radical 1,1-diphenyl-2-picryl-hydrazyl (DPPH) and 2,2'-azino-bis-3-ethylbenzthiazoline-6-sulfonic acid (ABTS) assays. Total phenolic and flavonoid contents were estimated in all four extracts. The hexane and chloroform extracts were tested for pro-apoptotic properties in HepG2 cells, and bioactive components were identified by gas chromatography-mass spectrometry (GC-MS) analysis.

RESULTS

The hexane and chloroform extracts showed dose-dependent and time-dependent cytotoxic effects. Morphological changes observed under fluorescence microscope related to apoptosis, and significant (P < 0.001) increases in caspase 3 and 9 levels were observed in hexane and chloroform extract-treated cells. Slight DNA fragmentation was observed only in response to the chloroform extract. mRNA expressions of p53 and Bax were significantly upregulated by low doses of hexane and chloroform extracts. Highest antioxidant activity was observed in the methanol extract. GC-MS profiles identified 24 and four major compounds in the hexane and chloroform extracts, respectively. These included some known anticancer compounds such as lupeol.

CONCLUSION

Cytotoxicity, antioxidant effects, and apoptosis-related changes exerted by hexane and chloroform extracts of S. hydrophyllacea concluded that these two extracts are good source for isolation of possible anticarcinogenic compounds.

SUMMARY

The hexane and chloroform extracts of Scyphiphora hydrophyllacea showed dose-dependent and time-dependent cytotoxic effects.Morphological changes related to apoptosis and significant (P < 0.001) increases in caspase 3 and 9 levels were observed in hexane and chloroform extract-treated cells.mRNA expressions of p53 and Bax were significantly upregulated by low doses of hexane and chloroform extracts.Highest antioxidant activity was observed in the methanol extract.GC-MS profiles identified 24 and four major compounds in the hexane and chloroform extracts, respectively. Abbreviation used: DPPH: 1,1-diphenyl-2-picryl-hydrazyl, ABTS: 2,2'-azinobis-3-ethylbenzthiazoline-6-sulfonic acid, GC-MS: gas chromatography-mass spectrometry, DNA: deoxyribonucleic acid, HCC: Hepatocellular carcinoma, GAE: gallic acid equivalents, SRB: sulforhodamine B, MTT: 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, AO/EB: acridine orange/ethidium bromide, GAPDH: Glyceraldehyde 3-phosphate dehydrogenase, IC50: half maximal inhibitory concentration; QE: quercetin equivalents, HE: hexane extract, CE: chloroform extract, EAE: ethyl acetate extract, ME: methanolic extract, TPC: total polyphenol content, TFC: total flavonoid content, ANOVA: Analysis of variance.

Long-Circulating Curcumin-Loaded Liposome Formulations with High Incorporation Efficiency, Stability and Anticancer Activity towards Pancreatic Adenocarcinoma Cell Lines In Vitro

The incorporation of hydrophobic drugs into liposomes improve their bioavailability and leads to increased stability and anticancer activity, along with decreased drug toxicity. Curcumin (Cur) is a natural polyphenol compound with a potent anticancer activity in pancreatic adenocarcinoma (PA). In the present study, different types of Cur-loaded liposomal formulations were prepared and characterized in terms of size, shape, zeta potential, optimal drug-to-lipid ratio and stability at 4°C, 37°C; and in human plasma in vitro. The best formulation in terms of these parameters was PEGylated, cholesterol-free formulation based upon hydrogenated soya PC (HSPC:DSPE-PEG₂₀₀₀:Cur, termed H5), which had a 0.05/10 molar ratio of drug-to-lipid, was found to be stable and had a 96% Cur incorporation efficiency. All Cur-loaded liposomal formulations had potent anticancer activity on the PA cancer cell lines AsPC-1 and BxPC-3, and were less toxic to a normal cell line (NHDF). Furthermore, apoptosis-induction induced by Cur in PA cells was associated with morphological changes including cell shrinkage, cytoplasmic blebbing, irregularity in shape and the externalization of cell membrane phosphatidylserine, which was preceded by an increase in intracellular reactive oxygen species (ROS) generation and caspase 3/7 activation. Because the liposomal formulations tested here, especially the H5 variant which exhibited slow release of the Cur in the human plasma test, the formulation may be stable enough to facilitate the accumulation of pharmacologically active amounts of Cur in target cancer tissue by EPR. Therefore, our formulations could serve as a promising therapeutic approach for pancreatic cancer and other cancers.

Golden Needle Mushroom: A Culinary Medicine with Evidenced-Based Biological Activities and Health Promoting Properties

Flammulina velutipes (enoki, velvet shank, golden needle mushroom or winter mushroom), one of the main edible mushrooms on the market, has long been recognized for its nutritional value and delicious taste. In recent decades, research has expanded beyond detailing its nutritional composition and delved into the biological activities and potential health benefits of its constituents. Many bioactive constituents from a range of families have been isolated from different parts of the mushroom, including carbohydrates, protein, lipids, glycoproteins, phenols, and sesquiterpenes. These compounds have been demonstrated to exhibit various biological activities, such as antitumour and anticancer activities, anti-atherosclerotic and thrombosis inhibition activity, antihypertensive and cholesterol lowering effects, anti-aging and antioxidant properties, ability to aid with restoring memory and overcoming learning deficits, anti-inflammatory, immunomodulatory, anti-bacterial, ribosome inactivation and melanosis inhibition. This review aims to consolidate the information concerning the phytochemistry and biological activities of various compounds isolated from F. velutipes to demonstrate that this mushroom is not only a great source of nutrients but also possesses tremendous potential in pharmaceutical drug development.

Resveratrol, piperine and apigenin differ in their NADPH-oxidase inhibitory and reactive oxygen species-scavenging properties

BACKGROUND

Many plant-derived chemicals have been studied for their potential benefits in ailments including inflammation, cancer, neurodegeneration, and cardiovascular disease. The health benefits of phytochemicals are often attributed to the targeting of reactive oxygen species (ROS). However, it is not always clear whether these agents act directly as antioxidants to remove ROS, or whether they act indirectly by blocking ROS production by enzymes such as NADPH oxidase (NOX) enzymes, or by influencing the expression of cellular pro- and anti- oxidants.

HYPOTHESIS/PURPOSE

Here we evaluate the pro- and anti-oxidant and NOX-inhibiting qualities of four phytochemicals: celastrol, resveratrol, apigenin, and piperine.

STUDY DESIGN

This work was done using the H661 cell line expressing little or no NOX, modified H661 cells expressing NOX1 and its subunits, and an EBV-transformed B-lymphoblastoid cell line expressing endogenous NOX2. ROS were measured using Amplex Red and nitroblue tetrazolium assays. In addition, direct ROS scavenging of hydrogen peroxide or superoxide generated were measured using Amplex Red and methyl cypridina luciferin analog (MCLA).

RESULTS

Of the four plant-derived compounds evaluated, only celastrol displayed NOX inhibitory activities, while celastrol and resveratrol both displayed ROS scavenging activity. Very little impact on ROS was observed with apigenin, or piperine.

CONCLUSION

The results of this study reveal the differences that exist between cell-free and intracellular pro-oxidant and antioxidant activities of several plant-derived compounds.

PAC down-regulates estrogen receptor alpha and suppresses epithelial-to-mesenchymal transition in breast cancer cells

Background

Triple-negative breast cancer (TNBC) is an aggressive histological subtype with limited treatment options and very poor prognosis following progression after standard chemotherapeutic regimens. Therefore, novel molecules and therapeutic options are urgently needed for this category of patients. Recently, we have identified PAC as a curcumin analogue with potent anti-cancer features.

Methods

HPLC was used to evaluate the stability of PAC and curcumin in PBS and also in circulating blood. Cytotoxicity/apoptosis was assessed in different breast cancer cell lines using propidium iodide/annexinV associated with flow cytometry. Furthermore, immunoblotting analysis determined the effects of PAC on different oncogenic proteins and pathways. Additionally, the real time xCELLigence RTCA technology was applied to investigate the effect of PAC on the cellular proliferation, migration and invasion capacities.

Results

PAC is more stable than curcumin in PBS and in circulating blood. Furthermore, we have shown differential sensitivity of estrogen receptor-alfa positive (ERα⁺) and estrogen receptor alfa negative (ERα⁻) breast cancer cells to PAC, which down-regulated ERα in both cell types. This led to complete disappearance of ERα in ERα⁻ cells, which express very low level of this receptor. Interestingly, specific down-regulation of ERα in receptor positive cells increased the apoptotic response of these cells to PAC, confirming that ERα inhibits PAC-dependent induction of apoptosis, which could be mediated through ERα down-regulation. Additionally, PAC inhibited the proliferation and suppressed the epithelial-to-mesenchymal transition process in breast cancer cells, with higher efficiency on the TNBC subtype. This effect was also observed in vivo on tumor xenografts. Additionally, PAC suppressed the expression/secretion of 2 important cytokines IL-6 and MCP-1, and consequently inhibited the paracrine procarcinogenic effects of breast cancer cells on breast stromal fibroblasts.

Conclusion

These results indicate that PAC could be considered as important candidate for future therapeutic options against the devastating TNBC subtype.

Engineering a Piperine Eluting Nanofibrous Patch for Cancer Treatment

The objective of this study was to engineer a biodegradable polymeric system for sustained release of piperine for cancer treatment. We prepared nanofibrous patches of poly(ε-caprolactone) (PCL) and gelatin (GEL) blends of different ratios by electrospinning. The PCL/GEL nanofibers were loaded with up to 30 wt % piperine, a phytochemical derived from black pepper, which is believed to exhibit anticancer, antiarthritis, antibacterial, antioxidant, and anti-inflammatory properties. Scanning electron microscopy revealed that the fiber diameter was in the range of 300-400 nm. Fourier-transform infrared spectroscopy confirmed that the drug was successfully loaded into the nanofiber mats. In vitro release kinetics revealed the sustained release of the drug with 50% release in 3 days from the PCL/GEL (50:50 by weight) blend fibers. The reduced viability and growth of HeLa and MCF-7 cancer cells on the piperine eluting nanofibers demonstrated anticancer activity in vitro. The proliferation of noncancerous cells such as NIH3T3 cells and human mesenchymal stem cells was affected to a markedly lesser extent. Flow cytometry revealed that the released piperine induced the generation of reactive oxygen species (ROS) and cell cycle arrest in the G2/M phase, leading to cell death of cancer cells. The findings of this study suggest that piperine-loaded nanofiber mats could be developed into implantable biodegradable patches for use in postsurgical cancer treatment.

β-Ionone and its analogs as promising anticancer agents

β-Ionone is an end-ring analog of β-carotenoids which widely distributed in fruit and vegetables. Recent studies have demonstrated anti-proliferative, anti-metastatic and apoptosis induction properties of β-ionone in vitro and in vivo. Also, the studies have focused on investigating the β-ionone action on different types of malignant cells and the possible mechanisms of action. Moreover, the quest of new synthetic β-ionone-based compounds possessing anti-proliferative, anti-metastatic and apoptosis induction activities may enable the discovery of compounds which can be used in combination regimes thus overcoming tumor resistance to conventional anticancer agents. These new agents will also be useful for targeting distinct signaling pathways, to activate selectively mechanisms for apoptosis in cancer cells but devoid of undesirable side effects. In this paper, we reviewed the potentialities of β-ionone and related compounds in cancer prevention and chemotherapy.

The coffee diterpene kahweol suppresses the cell proliferation by inducing cyclin D1 proteasomal degradation via ERK1/2, JNK and GKS3β-dependent threonine-286 phosphorylation in human colorectal cancer cells

Kahweol as a coffee-specific diterpene has been reported to exert anti-cancer properties. However, the mechanism responsible for the anti-cancer effects of kahweol is not fully understood. The main aim of this investigation was to determine the effect of kahweol on cell proliferation and the possible mechanisms in human colorectal cancer cells. Kahweol inhibited markedly the proliferation of human colorectal cancer cell lines such as HCT116, SW480. Kahweol decreased cyclin D1 protein level in HCT116 and SW480 cells. Contrast to protein levels, cyclin D1 mRNA level and promoter activity did not be changed by kahweol treatment. MG132 treatment attenuated kahweol-mediated cyclin D1 downregulation and the half-life of cyclin D1 was decreased in kahweol-treated cells. Kahweol increased phosphorylation of cyclin D1 at threonine-286 and a point mutation of threonine-286 to alanine attenuated cyclin D1 degradation by kahweol. Inhibition of ERK1/2 by PD98059, JNK by SP600125 or GSK3β by LiCl suppressed cyclin D1 phosphorylation and downregulation by kahweol. Furthermore, the inhibition of nuclear export by LMB attenuated cyclin D1 degradation by kahweol. In conclusion, kahweol-mediated cyclin D1 degradation may contribute to the inhibition of the proliferation in human colorectal cancer cells.

Phenethyl isothiocyanate (PEITC) suppresses prostate cancer cell invasion epigenetically through regulating microRNA-194

SCOPE

Tumor metastasis greatly contributes to the mortality of prostate cancer. The glucosinolate-derived phenethyl isothiocyanate (PEITC) has been widely documented to reduce the risk of prostate cancer by modulating multiple biologically relevant processes. Emerging evidence suggests that PEITC may exert its anti-cancer effects through epigenetic mechanisms including microRNAs. Altered levels of miRNA have been linked to tumor malignancy due to their capacity to regulate functional gene expression in carcinogenesis. Here, we assessed the effects of PEITC on miRNA expression which is related to PCa cell invasiveness.

METHODS AND RESULTS

Utilizing oligonucleotide microarray first identified the most affected miRNAs in LNCaP cells after PEITC treatment. Several top altered miRNAs were further validated using quantitative PCR. Interestingly, overexpression of miR-194 suppressed PC3 cell invasion in matrigel-coated Transwell chambers. Bone morphogenetic protein 1 (BMP1) was shown to be a direct target of miR-194. Downregulation of BMP1 by miR-194 or PEITC led to decreased expression of key oncogenic matrix metalloproteinases, MMP2 and MMP9. This in turn resulted in the suppression of tumor invasion.

CONCLUSION

Our results indicate that miR-194 downregulates the expression of oncogenic MMP2 and MMP9 by targeting BMP1, which suggests a potential new mechanistic target by which PEITC suppresses prostate cancer cell invasiveness.

[6]-Shogaol, a dietary phenolic compound, induces oxidative stress mediated mitochondrial dependant apoptosis through activation of proapoptotic factors in Hep-2 cells

Ginger (Zingiber officinale) is a well-known herb used in ethnomedicine. [6]-shogaol, a phenolic nature is a major constituent of ginger. In this study, we investigated the anticancer activity of [6]-shogaol in Laryngeal cancer (Hep-2) cells. We demonstrated the effects of [6]-shogaol on the cell growth and apoptosis in Hep-2 cells were analyzed by the generation of reactive oxygen species (ROS), the level of mitochondrial membrane potential (ΔYm), DNA damage and apoptotic morphological changes were analyzed by AO/EtBr, AO and Hoechst staining. Further, apoptotic protein expressions were analyzed by western blot analysis. Our results indicated that [6]-shogaol induces apoptosis as evidenced by loss of cell viability, enhanced ROS, lipid peroxidation results in altered mitochondrial membrane potential, increased DNA damage in Hep-2 cells. Further, the prooxidant role of [6]-shogaol inhibit Bcl-2 expression with the simultaneous up-regulation of Bax, Cytochrome c, Caspase-9 and -3 protein expressions were observed in Hep-2 cells. Thus, [6]-shogaol induces apoptosis in Hep-2 cells through inducing oxidative damage and modulate apoptotic marker expressions. Therefore, [6]-shogaol might be used as a therapeutic agent for the treatment of laryngeal cancer.

In silico identification of anti-cancer compounds and plants from traditional Chinese medicine database

There is a constant demand to develop new, effective, and affordable anti-cancer drugs. The traditional Chinese medicine (TCM) is a valuable and alternative resource for identifying novel anti-cancer agents. In this study, we aim to identify the anti-cancer compounds and plants from the TCM database by using cheminformatics. We first predicted 5278 anti-cancer compounds from TCM database. The top 346 compounds were highly potent active in the 60 cell lines test. Similarity analysis revealed that 75% of the 5278 compounds are highly similar to the approved anti-cancer drugs. Based on the predicted anti-cancer compounds, we identified 57 anti-cancer plants by activity enrichment. The identified plants are widely distributed in 46 genera and 28 families, which broadens the scope of the anti-cancer drug screening. Finally, we constructed a network of predicted anti-cancer plants and approved drugs based on the above results. The network highlighted the supportive role of the predicted plant in the development of anti-cancer drug and suggested different molecular anti-cancer mechanisms of the plants. Our study suggests that the predicted compounds and plants from TCM database offer an attractive starting point and a broader scope to mine for potential anti-cancer agents.

Nanotechnology for the delivery of phytochemicals in cancer therapy

The aim of this review is to summarize advances that have been made in the delivery of phytochemicals for cancer therapy by the use of nanotechnology. Over recent decades, much research effort has been invested in developing phytochemicals as cancer therapeutic agents. However, several impediments to their wide spread use as drugs still have to be overcome. Among these are low solubility, poor penetration into cells, high hepatic disposition, and narrow therapeutic index. Rapid clearance or uptake by normal tissues and wide tissue distribution result in low drug accumulation in the target tumor sites can result in undesired drug exposure in normal tissues. Association with or encapsulation in nanoscale drug carriers is a potential strategy to address these problems. This review discussed lessons learned on the use of nanotechnology for delivery of phytochemicals that been tested in clinical trials or are moving towards the clinic.

Naringenin-Mediated ATF3 Expression Contributes to Apoptosis in Human Colon Cancer

Naringenin (NAR) as one of the flavonoidsobserved in grapefruit has been reported to exhibit an anti-cancer activity. Activating transcription factor 3 (ATF3) is associated with apoptosis in human colon cancer cells. This study was performed to investigate the molecular mechanism by which NAR stimulates ATF3 expression and apoptosis in human colon cancer cells. NAR reduced the cell viability and induced an apoptosis in human colon cancer cells. ATF3 overexpression increased NAR-mediated cleaved PARP, while ATF3 knockdown attenuated the cleavage of PARP by NAR. NAR increased ATF3 expression in both protein and mRNA level, and increased the luciferase activity of ATF3 promoter in a dose-dependent manner. The responsible region for ATF3 transcriptional activation by NAR is located between -317 and -148 of ATF3 promoter. p38 inhibition blocked NAR-mediated ATF3 expression, its promoter activation and apoptosis. The results suggest that NAR induces apoptosis through p38-dependent ATF3 activation in human colon cancer cells.

The involvement of cyclin D1 degradation through GSK3β-mediated threonine-286 phosphorylation-dependent nuclear export in anti-cancer activity of mulberry root bark extracts

BACKGROUND

Mulberry root bark was shown to induce cyclin D1 proteasomal degradation in the human colorectal cancer cells. Still, the molecular mechanisms whereby mulberry root bark induces cyclin D1 proteasomal degradation remain largely unknown.

PURPOSE

In this study, the inhibitory effect of mulberry root bark (MRB) on the proliferation of human colorectal cancer cells and the mechanism of action were examined to evaluate its anti-cancer activity.

METHODS

Anti-proliferative effect was determined by MTT assay. RT-PCR and Western blotting were used to assess the mRNA and protein expression of related proteins.

RESULTS

MRB inhibited markedly the proliferation of human colorectal cancer cells (HCT116, SW480 and LoVo). In addition, the proliferation of human breast cancer cells (MDA-MB-231 and MCF-7) was suppressed by MRB treatment. However, MRB did not affect the growth of HepG-2 cells as a human hepatocellular carcinoma cell line. MRB effectively decreased cyclin D1 protein level in human colorectal cancer cells and breast cancer cells, but not in hepatocellular carcinoma cells. Contrast to protein levels, cyclin D1 mRNA level did not be changed by MRB treatment. Inhibition of proteasomal degradation by MG132 attenuated MRB-mediated cyclin D1 downregulation and the half-life of cyclin D1 was decreased in the cells treated with MRB. In addition, MRB increased phosphorylation of cyclin D1 at threonine-286 and a point mutation of threonine-286 to alanine attenuated MRB-mediated cyclin D1 degradation. Inhibition of GSK3β by LiCl suppressed cyclin D1 phosphorylation and downregulation by MRB. MRB decreased the nuclear level of cyclin D1 and the inhibition of nuclear export by LMB attenuated MRB-mediated cyclin D1 degradation.

CONCLUSION

MRB has anti-cancer activity by inducing cyclin D1 proteasomal degradation through cyclin D1 nuclear export via GSK3β-dependent threonine-286 phosphorylation. These findings suggest that possibly its extract could be used for treating colorectal cancer.