The interaction of bee products with temozolomide in human diffuse astrocytoma, glioblastoma multiforme and astroglia cell lines

Exploring the in vitro potential of royal jelly against glioblastoma and neuroblastoma: impact on cell proliferation, apoptosis, cell cycle, and the biomolecular content

Neuroblastoma and glioblastoma are the most commonly seen nervous system tumors, and their treatment is challenging. Relatively safe and easy acquisition of nutraceutical natural products make them suitable candidates for anticancer research. Royal jelly (RJ), a superfood, has many biological and pharmacological activities. This study was conducted to, for the first time, elucidate its anticancer efficiency, even in high doses, on neuroblastoma and glioblastoma cell lines through cell viability, apoptosis, cell cycle and biomolecular content evaluation. We performed experiments with RJ concentrations in the range of 1.25-10 mg mL-1 for 48 h. Cell viability assays revealed a notable cytotoxic effect of RJ in a concentration-dependent manner. Treatment with a high dose of RJ significantly increased the apoptotic cell population of both cell lines. Furthermore, we observed G0-G1 phase arrest in neuroblastoma cells but G2-M arrest in glioblastoma cells. All these cellular changes are closely associated with the alterations of the macromolecular makeup of the cells, such as decreased saturated lipid, protein, DNA and RNA amounts, protein conformational changes, decreased protein phosphorylation and increased protein carbonylation. These cellular changes are associated with RJ triggered-ROS formation. The clear segregation between the control and the RJ-treated groups proved these changes, obtained from the unsupervised and supervised chemometric analysis. RJ has good anticancer activity against nervous system cancers and could be safely used with current treatment strategies.

Royal Jelly: Beneficial Properties and Synergistic Effects with Chemotherapeutic Drugs with Particular Emphasis in Anticancer Strategies

Cancer is one of the major causes of death globally. Currently, various methods are used to treat cancer, including radiotherapy, surgery, and chemotherapy, all of which have serious adverse effects. A healthy lifestyle, especially a nutritional diet, plays a critical role in the treatment and prevention of many disorders, including cancer. The above notion, plus the trend in going back to nature, encourages consumers and the food industry to invest more in food products and to find potential candidates that can maintain human health. One of these agents, and a very notable food agent, is royal jelly (RJ), known to be produced by the hypopharyngeal and mandibular salivary glands of young nurse honeybees. RJ contains bioactive substances, such as carbohydrates, protein, lipids, peptides, mineral salts and polyphenols which contribute to the appreciated biological and pharmacological activities. Antioxidant, anticancer, anti-inflammatory, antidiabetic, and antibacterial impacts are among the well-recognized benefits. The combination of RJ or its constituents with anticancer drugs has synergistic effects on cancer disorders, enhancing the drug’s effectiveness or reducing its side effects. The purpose of the present review is to emphasize the possible interactions between chemotherapy and RJ, or its components, in treating cancer illnesses.

Polish and New Zealand Propolis as Sources of Antioxidant Compounds Inhibit Glioblastoma (T98G, LN-18) Cell Lines and Astrocytoma Cells Derived from Patient

Gliomas, including glioblastoma multiforme and astrocytoma, are common brain cancers in adults. Propolis is a natural product containing many active ingredients. The aim of this study was to compare the chemical composition, total phenolic content and concentration of toxic elements as well as the anticancer potential of Polish (PPE) and New Zealand (Manuka—MPE) propolis extracts on diffuse astrocytoma derived from patient (DASC) and glioblastoma (T98G, LN-18) cell lines. The antioxidants such as flavonoids and chalcones (pinocembrin, pinobanksin, pinobanksin 3-acetate and chrysin) were the main components in both types of propolis. The content of arsenic (As) and lead (Pb) in MPE was higher than PPE. The anti-proliferative study showed strong activity of PPE and MPE propolis on DASC, T98G, and LN-18 cells by apoptosis induction, cell cycle arrest and attenuated migration. These findings suggest that despite their different geographic origins, Polish and New Zealand propolis are sources of antioxidant compounds and show similar activity and a promising anti-glioma potential in in vitro study. However, further in vivo studies are required in order to assess therapeutic potential of propolis.

Bee Collected Pollen and Bee Bread: Bioactive Constituents and Health Benefits

Bee products were historically used as a therapheutic approach and in food consumption, while more recent data include important details that could validate them as food supplements due to their bioproperties, which support their future use as medicines. In this review data, data collected from bee pollen (BP) and bee bread (BB) essays will be discussed and detailed for their nutritional and health protective properties as functional foods. Dietary antioxidants intake derived from BP and BB have been associated with the prevention and clinical treatment of multiple diseases. The beneficial effects of BP and BB on health result from the presence of multiple polyphenols which possess anti-inflammatory properties, phytosterols and fatty acids, which play anticancerogenic roles, as well as polysaccharides, which stimulate immunological activity. From the main bioactivity studies with BP and BB, in vitro studies and animal experiments, the stimulation of apoptosis and the inhibition of cell proliferation in multiple cell lines could be one of the major therapeutic adjuvant effects to be explored in reducing tumor growth. Tables summarizing the main data available in this field and information about other bio-effects of BP and BB, which support the conclusions, are provided. Additionally, a discussion about the research gaps will be presented to help further experiments that complete the tree main World Health Organization (WHO) Directives of Efficiency, Safety and Quality Control for these products.

Anti-Cancer and Protective Effects of Royal Jelly for Therapy-Induced Toxicities in Malignancies

Royal jelly (RJ) is a glandular secretion produced by worker honeybees and is a special food for the queen honeybee. It results in a significant prolongation of the lifespan of the queen honeybee compared with the worker honeybees through anti-inflammatory, anti-oxidant and anti-microbial activities. Consequently, RJ is used as cosmetic and dietary supplement throughout the world. In addition, in vitro studies and animal experiments have demonstrated that RJ inhibits cell proliferation and stimulates apoptosis in various types of malignant cells and affects the production of various chemokines, anti-oxidants and growth factors and the expression of cancer-related molecules in patients with malignancies, especially in patients treated with anti-cancer agents. Therefore, RJ is thought to exert anti-cancer effects on tumor growth and exhibit protective functions against drug-induced toxicities. RJ has also been demonstrated to be useful for suppression of adverse events, the maintenance of the quality of life during treatment and the improvement of prognosis in animal models and patients with malignancies. To understand the mechanisms of the beneficial effects of RJ, knowledge of the changes induced at the molecular level by RJ with respect to cell survival, inflammation, oxidative stress and other cancer-related factors is essential. In addition, the effects of combination therapies of RJ and other anti-cancer agents or natural compounds are important to determine the future direction of RJ-based treatment strategies. Therefore, in this review, we have covered the following five issues: (1) the anti-cancer effects of RJ and its main component, 10-hydroxy-2-decenoic acid; (2) the protective effects of RJ against anti-cancer agent-induced toxicities; (3) the molecular mechanisms of such beneficial effects of RJ; (4) the safety and toxicity of RJ; and (5) the future directions of RJ-based treatment strategies, with a discussion on the limitations of the study of the biological activities of RJ.

Flavonoid Composition and Antitumor Activity of Bee Bread Collected in Northeast Portugal

Bee bread (BB) is a fermented mixture of plant pollen, honey, and bee saliva that worker bees use as food for larvae, and for young bees to produce royal jelly. In the present study, five BB samples, collected from Apis mellifera iberiensis hives located in different apiaries near Bragança, in the northeast region of Portugal, and one BB commercial sample were characterized by high-performance liquid chromatography coupled to a diode array detector and electrospray mass spectrometry (HPLC-DAD-ESI/MS) in terms of phenolic compounds, such as flavonoid glycoside derivatives. Furthermore, the samples were screened, using in vitro assays, against different human tumor cell lines, MCF-7 (breast adenocarcinoma), NCI-H460 (non-small cell lung cancer), HeLa (cervical carcinoma) and HepG2 (hepatocellular carcinoma), and also against non-tumor liver cells (porcine liver cells, PLP2). The main phenolic compounds found were flavonol derivatives, mainly quercetin, kaempferol, myricetin, isorhamnetin and herbacetrin glycoside derivatives. Thirty-two compounds were identified in the six BB samples, presenting BB1 and BB3 with the highest contents (6802 and 6480 µg/g extract, respectively) and the highest number of identified compounds. Two isorhamnetin glycoside derivatives, isrohamnetin-O-hexosyl-O-rutinoside and isorhamnetin-O-pentosyl-hexoside, were the most abundant compounds present in BB1; on the other hand, quercetin-3-O-rhamnoside was the most abundant flavonol in BB3. However, it was not possible to establish a correlation between the flavonoids and the observed low to moderate cytotoxicity (ranging from >400 to 68 µg/mL), in which HeLa and NCI-H460 cell lines were the most susceptible to the inhibition. To the authors' knowledge, this is the first report characterizing glycosidic flavonoids in BB samples, contributing to the chemical knowledge of this less explored bee product.

Anti-proliferative and anti-migration effects of Polish propolis combined with Hypericum perforatum L. on glioblastoma multiforme cell line U87MG

Background

Propolis and Hypericum perforatum L. are natural products which contain many active compounds and have numerous beneficial effects, including an antitumor effect. Gliobmastoma multiforme (GBM) is a common primary brain tumor with poor prognosis and limited treatment options. In this study, the effect of propolis (EEP) combined with H. perforatum L. (HPE) on glioblastoma cell line U87MG was investigated for the first time.

Methods

Anti-proliferative activity of EEP, HPE and their combination (EEP + HPE) was determined by a cytotoxicity test, DNA binding by [³H]-thymidine incorporation and cell migration assay. Anti-metastatic properties in U87MG treated with EEP, HPE and EEP + HPE were estimated on cells migration test (scratch assay) and metalloproteinases (MMP2 and MMP9) secretion (gelatin zymography).

Results

Combination of HPE and EEP extracts was found to have a time- and dose-dependent inhibitory effect on the viability of U87MG cells. This effect was significantly higher (p < 0.05) when compared to these two extracts applied separately, which was confirmed by the significant reduction of DNA synthesis and significantly higher mitochondrial membrane permeabilization. A significant decreasing in migration cells and in pro-MMP9 and pro-MMP2 secretion in U87MG cells were demonstrated after exposure to combination of EEP (30 μg/ml) with HPE (6.25 μg/ml).

Conclusions

In this study, the combination of ethanolic extract from propolis and ethanolic extract of fresh-cut H. perforatum L. was proved the ability to reduce invasiveness of glioma cells through the inhibition of MMP2 and MMP9 secretion and suppression of cell migration. It has a more potent anti-proliferative effect on U87MG glioma cell line compared to using propolis and H. perforatum L. separately. Further studies are required to verify whether the examined extracts can activate apoptotic pathways.

Electronic supplementary material

The online version of this article (doi:10.1186/s12906-016-1351-2) contains supplementary material, which is available to authorized users.

Derivatives of the pyrazolo[1,5-a]pyrimidine acetamide DPA-713 as translocator protein (TSPO) ligands and pro-apoptotic agents in human glioblastoma

The 18kDa translocator protein (TSPO) is a target for novel glioblastoma therapies due to its upregulation in this cancer and relatively low levels of expression in the healthy cortex. The pyrazolo[1,5-a]pyrimidine acetamides, exemplified by DPA-713 and DPA-714, are a class of high affinity TSPO ligands with selectivity over the central benzodiazepine receptor. In this study we have explored the potential anti-glioblastoma activity of a library of DPA-713 and DPA-714 analogues, and investigated the effect of amending the alkyl ether chain on TSPO affinity and functional potential. All ligands demonstrated nanomolar affinity for TSPO, but showed diverse functional activity, for example DPA-713 and DPA-714 did not affect the proliferation or viability of human T98G glioblastoma cells, while the hexyl ether and benzyl ether derivatives decreased proliferation of T98G cells without affecting proliferation in human fetal glial SVGp12 cells. These ligands also induced apoptosis and dissipated T98G mitochondrial membrane potential. This suggests that the nature of the alkyl ether chain of pyrazolo[1,5-a]pyrimidine acetamides has little influence on TSPO affinity but is important for functional activity of this class of TSPO ligands.