MicroRNA profile of polyunsaturated fatty acid treated glioma cells reveal apoptosis-specific expression changes

Understanding and applying gene-environment interactions: a guide for nutrition professionals with an emphasis on integration in African research settings

Noncommunicable diseases (NCDs) are influenced by the interplay between genetics and environmental exposures, particularly diet. However, many healthcare professionals, including nutritionists and dietitians, have limited genetic background and, therefore, they may lack understanding of gene-environment interactions (GxEs) studies. Even researchers deeply involved in nutrition studies, but with a focus elsewhere, can struggle to interpret, evaluate, and conduct GxE studies. There is an urgent need to study African populations that bear a heavy burden of NCDs, demonstrate unique genetic variability, and have cultural practices resulting in distinctive environmental exposures compared with Europeans or Americans, who are studied more. Although diverse and rapidly changing environments, as well as the high genetic variability of Africans and difference in linkage disequilibrium (ie, certain gene variants are inherited together more often than expected by chance), provide unparalleled potential to investigate the omics fields, only a small percentage of studies come from Africa. Furthermore, research evidence lags behind the practices of companies offering genetic testing for personalized medicine and nutrition. We need to generate more evidence on GxEs that also considers continental African populations to be able to prevent unethical practices and enable tailored treatments. This review aims to introduce nutrition professionals to genetics terms and valid methods to investigate GxEs and their challenges, and proposes ways to improve quality and reproducibility. The review also provides insight into the potential contributions of nutrigenetics and nutrigenomics to the healthcare sphere, addresses direct-to-consumer genetic testing, and concludes by offering insights into the field's future, including advanced technologies like artificial intelligence and machine learning.

The Involvement of Polyunsaturated Fatty Acids in Apoptosis Mechanisms and Their Implications in Cancer

Cancer is a significant global public health issue and, despite advancements in detection and treatment, the prognosis remains poor. Cancer is a complex disease characterized by various hallmarks, including dysregulation in apoptotic cell death pathways. Apoptosis is a programmed cell death process that efficiently eliminates damaged cells. Several studies have indicated the involvement of polyunsaturated fatty acids (PUFAs) in apoptosis, including omega-3 PUFAs such as alpha-linolenic acid, docosahexaenoic acid, and eicosapentaenoic acid. However, the role of omega-6 PUFAs, such as linoleic acid, gamma-linolenic acid, and arachidonic acid, in apoptosis is controversial, with some studies supporting their activation of apoptosis and others suggesting inhibition. These PUFAs are essential fatty acids, and Western populations today have a high consumption rate of omega-6 to omega-3 PUFAs. This review focuses on presenting the diverse molecular mechanisms evidence in both in vitro and in vivo models, to help clarify the controversial involvement of omega-3 and omega-6 PUFAs in apoptosis mechanisms in cancer.

MicroRNAs targeting peroxisome proliferator-activated receptor (PPAR) gene are differentially expressed in low birth weight placentae

INTRODUCTION

Peroxisome proliferator-activated receptors (PPARs) are activated by natural ligands like fatty acids and influence placental angiogenesis and pregnancy outcome. However, the underlying molecular mechanisms are not clear. This study aims to investigate the association of maternal and placental fatty acid levels with DNA methylation and microRNA regulation of PPARs in the placentae of women delivering low birth weight (LBW) babies.

METHODS

This study includes 100 women delivering normal birth weight (NBW) baby and 70 women delivering LBW baby. Maternal and placental fatty acids levels were estimated by gas chromatograph. Gene promoter methylation and mRNA expression of PPARs was analyzed using Epitect Methyl-II PCR assay kit and RT-PCR respectively. Expression of miRNAs targeting PPAR mRNA were analyzed using a Qiagen miRCURY LNA PCR Array on RT-PCR.

RESULTS

Placental docosahexaenoic acid (DHA) levels and placental mRNA expression of PPARα and PPARγ were lower (p < 0.05 for all) in the LBW group. Differential expression of miRNAs (upregulated miR-33a-5p and miR-22-5p; downregulated miR-301a-5p, miR-518d-5p, miR-27b-5p, miR-106a-5p, miR-21-5p, miR-548d-5p, miR-17-5p and miR-20a-5p) (p < 0.05 for all) was observed in the LBW group. Maternal and placental polyunsaturated fatty acids and total omega-3 fatty acids were positively associated while saturated fatty acids were negatively associated with expression of miRNAs (p < 0.05 for all). Placental expression of miRNAs were positively associated with birth weight (p < 0.05 for all).

DISCUSSION

Our data suggests that maternal fatty acid status is associated with changes in the placental expression of miRNAs targeting PPAR gene in women delivering LBW babies.

Effect of Polyunsaturated Fatty Acids on Temozolomide Drug-Sensitive and Drug-Resistant Glioblastoma Cells

Glioblastomas (GBMs) are notoriously difficult to treat, and the development of multiple drug resistance (MDR) is common during the course of the disease. The polyunsaturated fatty acids (PUFAs) gamma-linolenic acid (GLA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA) have been reported to improve MDR in several tumors including breast, bladder, and leukaemia. However, the effects of PUFAs on GBM cell MDR are poorly understood. The present study investigated the effects of PUFAs on cellular responses to temozolomide (TMZ) in U87MG cells and the TMZ-resistant (TMZR) cells derived from U87MG. Cells were treated with PUFAs in the absence or presence of TMZ and dose–response, viable cell counting, gene expression, Western blotting, flow cytometry, gas chromatography-mass spectrometry (GCMS), and drug efflux studies were performed. The development of TMZ resistance caused an increase in ABC transporter ABCB1 and ABCC1 expression. GLA-, EPA-, and DHA-treated cells had altered fatty acid composition and accumulated lipid droplets in the cytoplasm. The most significant reduction in cell growth was seen for the U87MG and TMZR cells in the presence of EPA. GLA and EPA caused more significant effects on ABC transporter expression than DHA. GLA and EPA in combination with TMZ caused significant reductions in rhodamine 123 efflux from U87MG cells but not from TMZR cells. Overall, these findings support the notion that PUFAs can modulate ABC transporters in GBM cells.

Lipid metabolism in tumor microenvironment: novel therapeutic targets

Bioactive lipid molecules have been proposed to play important roles linking obesity/metabolic syndrome and cancers. Studies reveal that aberrant lipid metabolic signaling can reprogram cancer cells and non-cancer cells in the tumor microenvironment, contributing to cancer initiation, progression, metastasis, recurrence, and poor therapeutic response. Existing evidence indicates that controlling lipid metabolism can be a potential strategy for cancer prevention and therapy. By reviewing the current literature on the lipid metabolism in various cancers, we summarized major lipid molecules including fatty acids and cholesterol as well as lipid droplets and discussed their critical roles in cancer cells and non-cancer in terms of either promoting- or anti-tumorigenesis. This review provides an overview of the lipid molecules in cellular entities and their tumor microenvironment, adding to the existing knowledge with lipid metabolic reprogramming in immune cells and cancer associated cells. Comprehensive understanding of the regulatory role of lipid metabolism in cellular entities and their tumor microenvironment will provide a new direction for further studies, in a shift away from conventional cancer research. Exploring the lipid-related signaling targets that drive or block cancer development may lead to development of novel anti-cancer strategies distinct from traditional approaches for cancer prevention and treatment.

Eicosapentaenoic acid enhanced apoptotic and oxidant effects of cisplatin via activation of TRPM2 channel in brain tumor cells

Cisplatin (CiSP) induced-overload Ca²⁺ entry results in the increase of mitochondrial oxidative stress and apoptosis in the cancer cell. TRPM2 cation channel is gated by the cytosolic ADP-ribose (ADPR) and reactive oxygen species (ROS). The high content of polyunsaturated fatty acid (PUFA) in the brain is a main target of ROS. Eicosapentaenoic acid (EPA) induces oxidant action via the enhance of PUFA content in the glioblastoma (DBTRG) cells. We hypothesized that a combination of CiSP and EPA may offer a potential therapy in the DBTRG cell by exerting the antitumor, oxidant, and apoptotic actions and stimulating Ca²⁺ influx and TRPM2 activity. In the DBTRG cells, we induced four groups as control, EPA (30 μM for 24 h), CiSP (25 μM for 24 h), and CiSP + EPA. The CiSP-induced intracellular Ca²⁺ responses to the TRPM2 activation were increased in the DBTRG cells from coming H₂O₂ and ADPR. The responses were decreased in the cells by the inhibitions of TRPM2 (ACA and 2/APB) and PARP/1 (DPQ and PJ34). The incubation of EPA further increased the intracellular Ca²⁺ responses, mitochondria function, and the generation of ROS in the DBTRGs. After the treatment of EPA, lipid peroxidation, apoptosis, cell death, caspase -3, -8, and -9 levels were further increased in the cells, although the levels of glutathione, glutathione peroxidase, cell numbers, and viability were further decreased in the cells. In summary, anticancer, apoptotic, and oxidant actions of CiSP were further increased via the activation of TRPM2 channel in the DBTRGs. Hence, TRPM2 stimulation via EPA could be used as an effective agent in the treatment of glioblastoma tumors with CiSP.

Dietary Factors and Risk of Glioma in Adults: A Systematic Review and Dose-Response Meta-Analysis of Observational Studies

Background

Gliomas are the most common primary intracranial tumors in adults. Inappropriate dietary habits are thought to be a risk factor for most human cancer, and glioma is no exception. However, the effect of dietary factors on glioma is not clear.

Objective

This review aims to quantitatively evaluate the association between various dietary intakes and glioma using a meta-analysis.

Methods

We searched articles on PubMed, the Cochrane Library, the Web of Science, and EMBASE from their inception until October 11, 2021. According to heterogeneity, the fixed-effects or random-effects model was selected to obtain the relative risk (RR) of merger. Based on the methods described by Greenland and Longnecker, we explored the dose-response relationship between dietary intakes and the risk of glioma. Subgroup analysis, sensitivity analysis, and publication bias were also used.

Results

This study reviewed 33 articles, including 3,606,015 controls and 8,831 patients with glioma. This study included 12 food groups. Compared with the lowest intakes, the highest intakes of tea (RR = 0.82, 95%CI:0.71–0.93), total vegetables (RR = 0.84, 95%CI: 0.70–1.00), green vegetables (RR = 0.80, 95%CI: 0.66–0.98), and orange vegetables (RR = 0.79, 95%CI: 0.66–0.96) significantly reduced the risk of glioma, while the highest intakes of grains (RR = 1.39, 95%CI: 1.16–1.66), processed meats (RR = 1.19, 95%CI: 1.00–1.42), and processed fish (RR = 1.37, 95%CI: 1.03–1.84) significantly increased the risk of glioma. The results of subgroup and sensitivity analyses remained unchanged. In the dose-response relationship, only tea was statistically significant. Taking an extra cup of tea every day reduced the risk of glioma by 4%.

Conclusions

Our analysis suggests that the intakes of tea, total vegetables, green vegetables, and orange vegetables may reduce the risk of glioma, while the intakes of grains, processed meats, and processed fish may increase the risk of glioma. Therefore, the effect of dietary factors on glioma should not be ignored.

Systematic Review Registration:https://www.crd.york.ac.uk/prospero/, CRD42022296658.

Fetal sex modulates placental microRNA expression, potential microRNA-mRNA interactions, and levels of amino acid transporter expression and substrates: INFAT study subpopulation analysis of n-3 LCPUFA intervention during pregnancy and associations with offspring body composition

Background

Previously, we revealed sexually dimorphic mRNA expression and responsiveness to maternal dietary supplementation with n-3 long-chain polyunsaturated fatty acids (LCPUFA) in placentas from a defined INFAT study subpopulation. Here, we extended these analyses and explored the respective placental microRNA expression, putative microRNA-mRNA interactions, and downstream target processes as well as their associations with INFAT offspring body composition.

Results

We performed explorative placental microRNA profiling, predicted microRNA-mRNA interactions by bioinformatics, validated placental target microRNAs and their putative targets by RT-qPCR and western blotting, and measured amino acid levels in maternal and offspring cord blood plasma and placenta. microRNA, mRNA, protein, and amino acid levels were associated with each other and with offspring body composition from birth to 5 years of age. Forty-six differentially regulated microRNAs were found. Validations identified differential expression for microRNA-99a (miR-99a) and its predicted target genes mTOR, SLC7A5, encoding L-type amino acid transporter 1 (LAT1), and SLC6A6, encoding taurine transporter (TauT), and their prevailing significant sexually dimorphic regulation. Target mRNA levels were mostly higher in placentas from control male than from female offspring, whereas respective n-3 LCPUFA responsive target upregulation was predominantly found in female placentas, explaining the rather balanced expression levels between the sexes present only in the intervention group. LAT1 and TauT substrates tryptophan and taurine, respectively, were significantly altered in both maternal plasma at 32 weeks’ gestation and cord plasma following intervention, but not in the placenta. Several significant associations were observed for miR-99a, mTOR mRNA, SLC7A5 mRNA, and taurine and tryptophan in maternal and cord plasma with offspring body composition at birth, 1 year, 3 and 5 years of age.

Conclusions

Our data suggest that the analyzed targets may be part of a sexually dimorphic molecular regulatory network in the placenta, possibly modulating gene expression per se and/or counteracting n-3 LCPUFA responsive changes, and thereby stabilizing respective placental and fetal amino acid levels. Our data propose placental miR-99, SLC7A5 mRNA, and taurine and tryptophan levels in maternal and fetal plasma as potentially predictive biomarkers for offspring body composition.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12860-021-00345-x.

Redox control of vascular biology

Redox control is lost when the antioxidant defense system cannot remove abnormally high concentrations of signaling molecules, such as reactive oxygen species (ROS). Chronically elevated levels of ROS cause oxidative stress that may eventually lead to cancer and cardiovascular and neurodegenerative diseases. In this review, we focus on redox effects in the vascular system. We pay close attention to the subcompartments of the vascular system (endothelium, smooth muscle cell layer) and give an overview of how redox changes influence those different compartments. We also review the core aspects of redox biology, cardiovascular physiology, and pathophysiology. Moreover, the topic-specific knowledgebase DES-RedoxVasc was used to develop two case studies, one focused on endothelial cells and the other on the vascular smooth muscle cells, as a starting point to possibly extend our knowledge of redox control in vascular biology.

Epigenetic Gene Regulation by Dietary Compounds in Cancer Prevention

Traditionally, cancer has been viewed as a set of diseases that are driven by the accumulation of genetic mutations, but we now understand that disruptions in epigenetic regulatory mechanisms are prevalent in cancer as well. Unlike genetic mutations, however, epigenetic alterations are reversible, making them desirable therapeutic targets. The potential for diet, and bioactive dietary components, to target epigenetic pathways in cancer is now widely appreciated, but our understanding of how to utilize these compounds for effective chemopreventive strategies in humans is in its infancy. This review provides a brief overview of epigenetic regulation and the clinical applications of epigenetics in cancer. It then describes the capacity for dietary components to contribute to epigenetic regulation, with a focus on the efficacy of dietary epigenetic regulators as secondary cancer prevention strategies in humans. Lastly, it discusses the necessary precautions and challenges that will need to be overcome before the chemopreventive power of dietary-based intervention strategies can be fully harnessed.

Interplay of non-coding RNAs and approved antimetabolites such as gemcitabine and pemetrexed in mesothelioma

Gemcitabine and pemetrexed are clinically approved antimetabolites for the therapy of mesothelioma diseases. These drugs are often applied in combination with platinum complexes and other drugs. The activity of antimetabolites depended on the expression levels of certain non-coding RNAs, in particular, of small microRNAs (miRNAs) and long non-coding RNAs (lncRNAs). The development of tumor resistance towards antimetabolites was regulated by non-coding RNAs. An overview of the interplay between gemcitabine/pemetrexed antimetabolites and non-coding RNAs in mesothelioma is provided. Further to this, various non-coding RNA-modulating agents are discussed which displayed positive effects on gemcitabine or pemetrexed treatment of mesothelioma diseases. A detailed knowledge of the connections of non-coding RNAs with antimetabolites will be constructive for the design of improved therapies in future.

Differential action of polyunsaturated fatty acids and eicosanoids on bleomycin-induced cytotoxicity to neuroblastoma cells and lymphocytes

INTRODUCTION

This study was conducted to examine whether bleomycin-induced growth inhibitory action on human neuroblastoma cells (IMR-32) is influenced by anti-inflammatory metabolites of polyunsaturated fatty acids (PUFAs): lipoxin A4 (LXA4), resolvin D1 and protectin D1 in vitro.

MATERIAL AND METHODS

The in vitro study was conducted using monolayer cultures of exponentially growing IMR-32 cells. The effects of various PUFAs and eicosanoids and anti-inflammatory metabolites of PUFAs such as lipoxin A4 (LXA4), resolvin D1 and protectin D1 on the growth of IMR-32 cells and human lymphocytes in vitro were investigated. The potential of PUFAs, eicosanoids and LXA4, resolvin D1 and protectin D1 to modify the growth inhibitory effects of bleomycin was also studied in IMR-32 cells and human lymphocytes.

RESULTS

PUFAs inhibited the growth of IMR-32 cells (EPA > DHA = AA > GLA = ALA > DGLA = LA) significantly (p < 0.001) while prostaglandins were found to be not effective. Bleomycin-induced growth inhibitory action on IMR-32 cells was augmented by PUFAs and its metabolites (p < 0.05). PUFAs and LXA4 did not inhibit the growth of human lymphocytes and bleomycin-induced growth inhibitory action was also not enhanced by these bioactive lipids.

CONCLUSIONS

Bioactive lipids have differential action on normal human lymphocytes and tumor cells in vitro. The apparent lack of effect of PUFAs in combination with bleomycin on the growth of human lymphocytes in comparison to their growth inhibitory action on IMR-32 cells suggests that PUFAs can be used in combination with bleomycin to target tumor cells with little concern over this combination's effect on the growth of human lymphocytes. Further studies are warranted to evaluate these differential effects under in vivo conditions.

The Association Between Index of Nutritional Quality (INQ) and Glioma and Evaluation of Nutrient Intakes of These Patients: A Case-Control Study

INTRODUCTION

Glioma is the most common adult brain tumors. Dietary factors may play a role in the etiology of glioma. The Index of Nutritional Quality (INQ) provides a general overview for the nutrient content of a food or a diet. This study aimed to investigate the association between INQ and glioma and nutrient intakes.

MATERIAL AND METHODS

This study was included 128 patients and 256 controls. Dietary intakes of the subjects were evaluated by a food frequency questionnaire (FFQ) and FFQ-derived dietary data were used to calculate INQ scores. Logistic regression was used to calculate the odds ratios and 95% confidence intervals.

RESULTS

Cases had higher intake of total fat, saturated fatty acid (SFA), meats, hydrogenated oils and controls had higher intake of monounsaturated fatty acid, polyunsaturated fatty acid, calcium, dairy, fruits, and nuts. Only the INQ of vitamin C, vitamin E, calcium, and fiber are higher in controls. An inverse association was observed between glioma and INQ of calcium, vitamin E, vitamin C, and fiber.

CONCLUSION

The results of this study propose a healthy diet such as high intake of vitamins C and E, calcium, fiber, food groups like fruits and vegetables, and low-fat milk and nuts; and low consumption of total fat, SFA, and red meat may be protective against glioma.

Identification of differentially expressed miRNAs in the fatty liver of Landes goose (Anser anser)

Unlike mammals, in palmipedes de novo lipogenesis from diet takes place mostly in the liver. The French Landes Goose is famous for its high capacity and susceptibility to fatty liver production. While miRNAs play a critical role in the posttranscriptional regulation of gene expression, miRNAs that are involved in the regulation of goose hepatic steatosis have yet to be elucidated. Using high-throughput sequencing, we analyzed miRNAs expression profile of Landes goose liver after overfeeding for 21 days. Aan-miR-122-5p was the most frequently sequenced known miRNA, but it was unchanged after overfeeding. Compared with normal liver, we identified that 16 conserved miRNAs were up-regulated while the other 9 conserved miRNAs were down-regulated in fatty livers. Many of their predicted target genes played key roles in metabolic pathways leading to the development of hepatic steatosis in the goose by KEGG pathways analysis. ACSL1 and ELOVL6 were critical genes in hepatic lipid metabolism and had opposite expression patterns with aan-miR-203a and aan-miR-125b-5p, respectively. And we validated that aan-miR-203a and aan-miR-125b-5p might involve in the regulation of hepatic lipid metabolism by targeting ACSL1 and ELOVL6, respectively. These results add to our current understanding of the regulation network in goose lipid metabolism.

Implications of dietary ω-3 and ω-6 polyunsaturated fatty acids in breast cancer

Breast cancer represents one of the most common forms of cancer in women worldwide, with an increase in the number of newly diagnosed patients in the last decade. The role of fatty acids, particularly of a diet rich in ω-3 and ω-6 polyunsaturated fatty acids (PUFAs), in breast cancer development is not fully understood and remains controversial due to their complex mechanism of action. However, a large number of animal models and cell culture studies have demonstrated that high levels of ω-3 PUFAs have an inhibitory role in the development and progression of breast cancer, compared to ω-6 PUFAs. The present review focused on recent studies regarding the correlation between dietary PUFAs and breast cancer development, and aimed to emphasize the main molecular mechanisms involved in the modification of cell membrane structure and function, modulation of signal transduction pathways, gene expression regulation, and antiangiogenic and antimetastatic effects. Furthermore, the anticancer role of ω-3 PUFAs through the modulation of microRNA expression levels was also reviewed.

Impact of Polyunsaturated Fatty Acids on miRNA Profiles of Monocytes/Macrophages and Endothelial Cells-A Pilot Study

Alteration of miRNAs and dietary polyunsaturated fatty acids (PUFAs) underlies vascular inflammation. PUFAs are known to be incorporated into the cell membrane of monocytes/macrophages or endothelial cells, the major cellular players of vascular diseases, thereby affecting cellular signal transduction. Nevertheless, there are no investigations concerning the PUFA impact on miRNA expression by these cells. With regard to the key role miRNAs play for overall cellular functionality, this study aims to elucidate whether PUFAs affect miRNA expression profiles. To this end, the monocyte/macrophage cell line RAW264.7 and the endothelial cell line TIME were enriched with either docosahexaenoic acid (DHA; n3-PUFA) or arachidonic acid (AA; n6-PUFA) until reaching a stable incorporation into the plasma membrane and, at least in part, exposed to an inflammatory milieu. Expressed miRNAs were determined by deep sequencing, and compared to unsupplemented/unstimulated controls. Data gained clearly show that PUFAs in fact modulate miRNA expression of both cell types analyzed regardless the presence/absence of an inflammatory stimulator. Moreover, certain miRNAs already linked to vascular inflammation were found to be affected by cellular PUFA enrichment. Hence, vascular inflammation appears to be influenced by dietary fatty acids, inter alia, via PUFA-mediated modulation of the type and amount of miRNAs synthesized by cells involved in the inflammatory process.

Inflammation and Cancer: Extra- and Intracellular Determinants of Tumor-Associated Macrophages as Tumor Promoters

One of the hallmarks of cancer-related inflammation is the recruitment of monocyte-macrophage lineage cells to the tumor microenvironment. These tumor infiltrating myeloid cells are educated by the tumor milieu, rich in cancer cells and stroma components, to exert functions such as promotion of tumor growth, immunosuppression, angiogenesis, and cancer cell dissemination. Our review highlights the ontogenetic diversity of tumor-associated macrophages (TAMs) and describes their main phenotypic markers. We cover fundamental molecular players in the tumor microenvironment including extra- (CCL2, CSF-1, CXCL12, IL-4, IL-13, semaphorins, WNT5A, and WNT7B) and intracellular signals. We discuss how these factors converge on intracellular determinants (STAT3, STAT6, STAT1, NF-κB, RORC1, and HIF-1α) of cell functions and drive the recruitment and polarization of TAMs. Since microRNAs (miRNAs) modulate macrophage polarization key miRNAs (miR-146a, miR-155, miR-125a, miR-511, and miR-223) are also discussed in the context of the inflammatory myeloid tumor compartment. Accumulating evidence suggests that high TAM infiltration correlates with disease progression and overall poor survival of cancer patients. Identification of molecular targets to develop new therapeutic interventions targeting these harmful tumor infiltrating myeloid cells is emerging nowadays.

Fish intake and the risk of brain tumor: a meta-analysis with systematic review

Background

Fish, rich in ω-3 polyunsaturated fatty acids, has been found to be associated with lower risk of several types of cancer risk, and beneficial for brain development. However, the association between fish intake and brain tumor risk is still inconsistent. Therefore, we conducted a meta-analysis to clarify the association.

Methods

Relevant studies were identified from PubMed and EMBASE databases. The pooled relative risks were obtained by the fixed-effects model when no substantial heterogeneity was observed. Otherwise, the random-effects model was employed. Subgroup and publication bias analyses were also performed.

Results

Nine observational studies were included in the meta-analysis. The pooled relative risk of brain cancer for the highest vs. lowest category of fish intake was 0.83 (95% confidence interval [CI]: 0.70–0.99). No significant heterogeneity was detected. Dose-response analysis showed that the RR per 100 g/day increase in fish intake was 0.95 (95% CI: 0.91–0.98). The results remained unchanged in subgroup and sensitivity analyses.

Conclusions

The results of our meta-analysis suggest that fish intake might be associated with lower risk of brain cancer risk. The finding should be further confirmed by future cohort studies with validated questionnaires and strict control of confounders.

Electronic supplementary material

The online version of this article (doi:10.1186/s12937-016-0223-4) contains supplementary material, which is available to authorized users.

Contributions of polyunsaturated fatty acids (PUFA) on cerebral neurobiology: an integrated omics approach with epigenomic focus

The epigenetic landscape is vulnerable to diets. Here, we investigated the influence of different polyunsaturated fatty acids (PUFA) dietary supplements on rodents' nervous system development and functions and potential consequences to neurodegenerative disorders. Our previous nutrigenomics study showed significant impact of high n-3 PUFA-enriched diet (ERD) on synaptogenesis and various neuromodulators. The present study introduced a second equicaloric diet with n-6 PUFA balanced by n-3 PUFA (BLD). The typical lab diet with high n-6 PUFA was the baseline. Transcriptomic and epigenetic investigations, namely microRNA (miRNA) and DNA methylation assays, were carried out on the hemibrains of the C57BL/6j mice fed on any of these three diets from their neonatal age to midlife. Integrating the multiomics data, we focused on the genes encoding both hypermethylated CpG islands and suppressed transcripts. In addition, miRNA:mRNA pairs were screened to identify those overexpressed miRNAs that reduced transcriptional expressions. The majority of miRNAs overexpressed by BLD are associated with Alzheimer's and schizophrenia. BLD implicated long-term potentiation, memory, cognition and learning, primarily via hypermethylation of those genes that enrich the calcium-releasing neurotransmitters. ERD caused hypermethylation of those genes that enrich cytoskeletal development networks and promote the formation of neuronal precursors. We drew the present observations in light of our limited knowledge regarding the epigenetic influences on biofunctions. A more comprehensive study is essential to understand the broad influences of dietary supplements and to suggest optimal dietary solutions for neurological disorders.

Prioritizing cancer-related microRNAs by integrating microRNA and mRNA datasets

MicroRNAs (miRNAs) are small non-coding RNAs regulating the expression of target genes, and they are involved in cancer initiation and progression. Even though many cancer-related miRNAs were identified, their functional impact may vary, depending on their effects on the regulation of other miRNAs and genes. In this study, we propose a novel method for the prioritization of candidate cancer-related miRNAs that may affect the expression of other miRNAs and genes across the entire biological network. For this, we propose three important features: the average expression of a miRNA in multiple cancer samples, the average of the absolute correlation values between the expression of a miRNA and expression of all genes, and the number of predicted miRNA target genes. These three features were integrated using order statistics. By applying the proposed approach to four cancer types, glioblastoma, ovarian cancer, prostate cancer, and breast cancer, we prioritized candidate cancer-related miRNAs and determined their functional roles in cancer-related pathways. The proposed approach can be used to identify miRNAs that play crucial roles in driving cancer development, and the elucidation of novel potential therapeutic targets for cancer treatment.

Non-coding RNA/microRNA-modulatory dietary factors and natural products for improved cancer therapy and prevention: Alkaloids, organosulfur compounds, aliphatic carboxylic acids and water-soluble vitamins

Non-coding small RNA molecules, the microRNAs (miRNAs), contribute decisively to the epigenetic regulation processes in cancer cells. Problematic pathogenic properties of cancer cells and the response of cancers towards anticancer drugs are highly influenced by miRNAs. Both increased drug activity and formation of tumor resistance are regulated by miRNAs. Further to this, the survival and proliferation of cancer cells and the formation of metastases is based on the modulated expression of certain miRNAs. In particular, drug-resistant cancer stem-like cells (CSCs) depend on the presence and absence of specific miRNAs. Fortunately, several small molecule natural compounds were discovered that target miRNAs involved in the modulation of tumor aggressiveness and drug resistance. This review gives an overview of the effects of a selection of naturally occurring small molecules (alkaloids, organosulfur compounds, aliphatic carboxylic acids and water-soluble vitamins) on miRNAs that are closely tangled with cancer diseases.

How Diet Intervention via Modulation of DNA Damage Response through MicroRNAs May Have an Effect on Cancer Prevention and Aging, an in Silico Study

The DNA damage response (DDR) is a molecular mechanism that cells have evolved to sense DNA damage (DD) to promote DNA repair, or to lead to apoptosis, or cellular senescence if the damage is too extensive. Recent evidence indicates that microRNAs (miRs) play a critical role in the regulation of DDR. Dietary bioactive compounds through miRs may affect activity of numerous genes. Among the most studied bioactive compounds modulating expression of miRs are epi-gallocatechin-3-gallate, curcumin, resveratrol and n3-polyunsaturated fatty acids. To compare the impact of these dietary compounds on DD/DDR network modulation, we performed a literature search and an in silico analysis by the DIANA-mirPathv3 software. The in silico analysis allowed us to identify pathways shared by different miRs involved in DD/DDR vis-à-vis the specific compounds. The results demonstrate that certain miRs (e.g., -146, -21) play a central role in the interplay among DD/DDR and the bioactive compounds. Furthermore, some specific pathways, such as "fatty acids biosynthesis/metabolism", "extracellular matrix-receptor interaction" and "signaling regulating the pluripotency of stem cells", appear to be targeted by most miRs affected by the studied compounds. Since DD/DDR and these pathways are strongly related to aging and carcinogenesis, the present in silico results of our study suggest that monitoring the induction of specific miRs may provide the means to assess the antiaging and chemopreventive properties of particular dietary compounds.

The Curcumin Analog C-150, Influencing NF-κB, UPR and Akt/Notch Pathways Has Potent Anticancer Activity In Vitro and In Vivo

C-150 a Mannich-type curcumin derivative, exhibited pronounced cytotoxic effects against eight glioma cell lines at micromolar concentrations. Inhibition of cell proliferation by C-150 was mediated by affecting multiple targets as confirmed at transcription and protein level. C-150 effectively reduced the transcription activation of NFkB, inhibited PKC-alpha which are constitutively over-expressed in glioblastoma. The effects of C-150 on the Akt/ Notch signaling were also demonstrated in a Drosophila tumorigenesis model. C-150 reduced the number of tumors in Drosophila with similar efficacy to mitoxantrone. In an in vivo orthotopic glioma model, C-150 significantly increased the median survival of treated nude rats compared to control animals. The multi-target action of C-150, and its preliminary in vivo efficacy would render this curcumin analogue as a potent clinical candidate against glioblastoma.

Inhibition of colon cancer growth by docosahexaenoic acid involves autocrine production of TNFα

The omega-3 polyunsaturated fatty acid docosahexaenoic acid (DHA) has anti-inflammatory and anti-cancer properties. Among pro-inflammatory mediators, tumor necrosis factor α (TNFα) plays a paradoxical role in cancer biology with induction of cancer cell death or survival depending on the cellular context. The objective of the study was to evaluate the role of TNFα in DHA-mediated tumor growth inhibition and colon cancer cell death. The treatment of human colorectal cancer cells, HCT-116 and HCT-8 cells, with DHA triggered apoptosis in autocrine TNFα-dependent manner. We demonstrated that DHA-induced increased content of TNFα mRNA occurred through a post-transcriptional regulation via the down-regulation of microRNA-21 (miR-21) expression. Treatment with DHA led to nuclear accumulation of Foxo3a that bounds to the miR-21 promoter triggering its transcriptional repression. Moreover, inhibition of RIP1 kinase and AMP-activated protein kinase α reduced Foxo3a nuclear-cytoplasmic shuttling and subsequent increase of TNFα expression through a decrease of miR-21 expression in DHA-treated colon cancer cells. Finally, we were able to show in HCT-116 xenograft tumor-bearing nude mice that a DHA-enriched diet induced a decrease of human miR-21 expression and an increase of human TNFα mRNA expression limiting tumor growth in a cancer cell-derived TNFα dependent manner. Altogether, the present work highlights a novel mechanism for anti-cancer action of DHA involving colon cancer cell death mediated through autocrine action of TNFα.

Omega-3 Fatty Acids and Cancer Cell Cytotoxicity: Implications for Multi-Targeted Cancer Therapy

Cancer is a major disease worldwide. Despite progress in cancer therapy, conventional cytotoxic therapies lead to unsatisfactory long-term survival, mainly related to development of drug resistance by tumor cells and toxicity towards normal cells. n-3 polyunsaturated fatty acids (PUFAs), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), can exert anti-neoplastic activity by inducing apoptotic cell death in human cancer cells either alone or in combination with conventional therapies. Indeed, n-3 PUFAs potentially increase the sensitivity of tumor cells to conventional therapies, possibly improving their efficacy especially against cancers resistant to treatment. Moreover, in contrast to traditional therapies, n-3 PUFAs appear to cause selective cytotoxicity towards cancer cells with little or no toxicity on normal cells. This review focuses on studies investigating the cytotoxic activity of n-3 PUFAs against cancer cells via apoptosis, analyzing the molecular mechanisms underlying this effective and selective activity. Here, we highlight the multiple molecules potentially targeted by n-3 PUFAs to trigger cancer cell apoptosis. This analysis can allow a better comprehension of the potential cytotoxic therapeutic role of n-3 PUFAs against cancer, providing specific information and support to design future pre-clinical and clinical studies for a better use of n-3 PUFAs in cancer therapy, mainly combinational therapy.

Does plasma membrane lipid composition impact the miRNA-mediated regulation of vascular inflammation?

BACKGROUND

Both PUFA and miRNAs are believed to be of importance in vascular diseases. On the one hand diverse nutrition societies recommend PUFA consumption to dampen inflammatory processes. On the other hand scientists intensify efforts to use miRNAs for diagnostics or therapy in context of vascular disorders.

PRESENTATION OF THE HYPOTHESIS

There might be is a causal link between the plasma membrane lipid composition and the miRNA expression of monocytes and endothelial cells. PUFA enrichment of cells may affect the type and the amount of particular miRNAs produced. In this way dietary fatty acids are supposed to impact the miRNA-mediated regulation of vascular inflammatory processes.

PROPOSED EXPERIMENTAL SETTING TO TEST THE HYPOTHESIS

PUFA-supplemented monocytes and endothelial cells are analyzed with respect to membrane fatty acid patterns, typical markers of vascular inflammation and miRNA expression. Experiments are performed both for undifferentiated/unstimulated as well as for differentiated/stimulated cells. Verification of identified miRNA targets is performed by means of mimics/antagomirs.

IMPLICATIONS OF THE HYPOTHESIS

Innovative mechanism of action, which could point the way to a new understanding of the PUFA-mediated modulation of cellular signal transduction. If confirmed experimentally, it might stimulate vascular inflammation research and immunologic lipid science, hence, acting as source of inspiration for future therapeutic interventions in vascular diseases.

Dietary Flaxseed Mitigates Impaired Skeletal Muscle Regeneration: in Vivo, in Vitro and in Silico Studies

BACKGROUND

Diets enriched with n-3 polyunsaturated fatty acids (n-3 PUFAs) have been shown to exert a positive impact on muscle diseases. Flaxseed is one of the richest sources of n-3 PUFA acid α-linolenic acid (ALA). The aim of this study was to assess the effects of flaxseed and ALA in models of skeletal muscle degeneration characterized by high levels of Tumor Necrosis Factor-α (TNF).

METHODS

The in vivo studies were carried out on dystrophic hamsters affected by muscle damage associated with high TNF plasma levels and fed with a long-term 30% flaxseed-supplemented diet. Differentiating C2C12 myoblasts treated with TNF and challenged with ALA represented the in vitro model. Skeletal muscle morphology was scrutinized by applying the Principal Component Analysis statistical method. Apoptosis, inflammation and myogenesis were analyzed by immunofluorescence. Finally, an in silico analysis was carried out to predict the possible pathways underlying the effects of n-3 PUFAs.

RESULTS

The flaxseed-enriched diet protected the dystrophic muscle from apoptosis and preserved muscle myogenesis by increasing the myogenin and alpha myosin heavy chain. Moreover, it restored the normal expression pattern of caveolin-3 thereby allowing protein retention at the sarcolemma. ALA reduced TNF-induced apoptosis in differentiating myoblasts and prevented the TNF-induced inhibition of myogenesis, as demonstrated by the increased expression of myogenin, myosin heavy chain and caveolin-3, while promoting myotube fusion. The in silico investigation revealed that FAK pathways may play a central role in the protective effects of ALA on myogenesis.

CONCLUSIONS

These findings indicate that flaxseed may exert potent beneficial effects by preserving skeletal muscle regeneration and homeostasis partly through an ALA-mediated action. Thus, dietary flaxseed and ALA may serve as a useful strategy for treating patients with muscle dystrophies.

Nuclear Factor of Activated T Cells-dependent Down-regulation of the Transcription Factor Glioma-associated Protein 1 (GLI1) Underlies the Growth Inhibitory Properties of Arachidonic Acid

Numerous reports have demonstrated a tumor inhibitory effect of polyunsaturated fatty acids (PUFAs). However, the molecular mechanisms modulating this phenomenon are in part poorly understood. Here, we provide evidence of a novel antitumoral mechanism of the PUFA arachidonic acid (AA). In vivo and in vitro experiments showed that AA treatment decreased tumor growth and metastasis and increased apoptosis. Molecular analysis of this effect showed significantly reduced expression of a subset of antiapoptotic proteins, including BCL2, BFL1/A1, and 4-1BB, in AA-treated cells. We demonstrated that down-regulation of the transcription factor glioma-associated protein 1 (GLI1) in AA-treated cells is the underlying mechanism controlling BCL2, BFL1/A1, and 4-1BB expression. Using luciferase reporters, chromatin immunoprecipitation, and expression studies, we found that GLI1 binds to the promoter of these antiapoptotic molecules and regulates their expression and promoter activity. We provide evidence that AA-induced apoptosis and down-regulation of antiapoptotic genes can be inhibited by overexpressing GLI1 in AA-sensitive cells. Conversely, inhibition of GLI1 mimics AA treatments, leading to decreased tumor growth, cell viability, and expression of antiapoptotic molecules. Further characterization showed that AA represses GLI1 expression by stimulating nuclear translocation of NFATc1, which then binds the GLI1 promoter and represses its transcription. AA was shown to increase reactive oxygen species. Treatment with antioxidants impaired the AA-induced apoptosis and down-regulation of GLI1 and NFATc1 activation, indicating that NFATc1 activation and GLI1 repression require the generation of reactive oxygen species. Collectively, these results define a novel mechanism underlying AA antitumoral functions that may serve as a foundation for future PUFA-based therapeutic approaches.

Lipidomic analysis reveals a radiosensitizing role of gamma-linolenic acid in glioma cells

Previous studies have demonstrated that gamma-linolenic acid (GLA) is effective against glioma cells under both in vitro and in vivo conditions. In the present study we determined how GLA alone or in combination with irradiation alters the fatty acid (FA) and lipid profiles, the lipid droplet (LD) content, the lipid biosynthetic gene expression and the apoptosis of glioma cells. In GLA-treated cells direct correlations were found between the levels of various FAs and the expression of the corresponding FA biosynthetic genes. The total levels of saturated and monosaturated FAs decreased in concert with the down-regulation of FASN and SCD1 gene expression. Similarly, decreased FADS1 gene expression was paralleled by lowered arachidonic acid (20:4 n-6) and eicosapentaenoic acid (20:5 n-3) contents, while the down-regulation of FADS2 expression was accompanied by a diminished docosahexaenoic acid (22:6 n-3) content. Detailed mass spectrometric analyses revealed that individual treatments gave rise to distinct lipidomic fingerprints. Following uptake, GLA was subjected to elongation, resulting in dihomo-gamma-linolenic acid (20:3 n-6, DGLA), which was used for the synthesis of the LD constituent triacylglycerols and cholesteryl esters. Accordingly, an increased number of LDs were observed in response to GLA administration after irradiation. GLA increased the radioresponsiveness of U87 MG cells, as demonstrated by an increase in the number of apoptotic cells determined by FACS analysis. In conclusion, treatment with GLA increased the apoptosis of irradiated glioma cells, and GLA might therefore increase the therapeutic efficacy of irradiation in the treatment of gliomas.

Consumption of distinct dietary lipids during early pregnancy differentially modulates the expression of microRNAs in mothers and offspring

Diet during pregnancy and lactation influences the offspring’s health in the long-term. Indeed, human epidemiological studies and animal experiments suggest that different type of fatty acids consumption during pregnancy affect offspring development and susceptibility to metabolic disorders. Epigenetic changes are thought to be elicited by dietary factors during critical timing of development. microRNAs (miRNAs) are versatile regulators of gene expression. Thus, we aimed to determine the influence of different fatty acids on miRNA expression in offspring when given during early pregnancy. We fed pregnant either soybean (SO), olive (OO), fish (FO), linseed (LO), or palm-oil (PO) diets from conception to day 12 of gestation; and standard diet thereafter. miRNA expression was assessed in liver an adipose tissue of pregnant rats and their virgin counterparts. While liver concentrations of fatty acids in pregnant or virgin rats replicated those of the diets consumed during early pregnancy, their pups’ liver tissue marginally reflected those of the respective experimental feeds. By contrast, the liver fatty acid profile of adult offsprings was similar, regardless of the diet fed during gestation. Different parental miRNAs were modulated by the different type of fatty acid: in adult offspring, miR-215, miR-10b, miR-26, miR-377-3p, miR-21, and miR-192 among others, were differentially modulated by the different fatty acids fed during early pregnancy. Overall, our results show that maternal consumption of different types of fatty acids during early pregnancy influences miRNA expression in both maternal and offspring tissues, which may epigenetically explain the long-term phenotypic changes of the offspring.

PUFA diets alter the microRNA expression profiles in an inflammation rat model

Omega-3 and -6 polyunsaturated fatty acids (PUFAs) can directly or indirectly regulate immune homeostasis via inflammatory pathways, and components of these pathways are crucial targets of microRNAs (miRNAs). However, no study has examined the changes in the miRNA transcriptome during PUFA-regulated inflammatory processes. Here, we established PUFA diet-induced autoimmune-prone (AP) and autoimmune-averse (AA) rat models, and studied their physical characteristics and immune status. Additionally, miRNA expression patterns in the rat models were compared using microarray assays and bioinformatic methods. A total of 54 miRNAs were differentially expressed in common between the AP and the AA rats, and the changes in rno-miR-19b-3p, -146b-5p and -183-5p expression were validated using stem-loop reverse transcription-quantitative polymerase chain reaction. To better understand the mechanisms underlying PUFA-regulated miRNA changes during inflammation, computational algorithms and biological databases were used to identify the target genes of the three validated miRNAs. Furthermore, Gene Ontology (GO) term annotation and KEGG pathway analyses of the miRNA targets further allowed to explore the potential implication of the miRNAs in inflammatory pathways. The predicted PUFA-regulated inflammatory pathways included the Toll-like receptor (TLR), T cell receptor (TCR), NOD-like receptor (NLR), RIG-I-like receptor (RLR), mitogen-activated protein kinase (MAPK) and the transforming growth factor-β (TGF-β) pathway. This study is the first report, to the best of our knowledge, on in vivo comparative profiling of miRNA transcriptomes in PUFA diet-induced inflammatory rat models using a microarray approach. The results provide a useful resource for future investigation of the role of PUFA-regulated miRNAs in immune homeostasis.

Manipulating miRNA Expression: A Novel Approach for Colon Cancer Prevention and Chemotherapy

Small non-coding RNA has been implicated in the control of various cellular processes such as proliferation, apoptosis, and differentiation. About 50% of the miRNA genes are positioned in cancer-associated genomic regions. Several studies have shown that miRNA expression is deregulated in cancer and modulating their expression has reversed the cancer phenotype. Therefore, mechanisms to modulate microRNA (miRNA) activity have provided a novel opportunity for cancer prevention and therapy. In addition, a common cause for development of colorectal cancers is environmental and lifestyle factors. One such factor, diet has been shown to modulate miRNA expression in colorectal cancer patients. In this chapter, we will summarize the work demonstrating that miRNAs are novel promising drug targets for cancer chemoprevention and therapy. Improved delivery, increased stability and enhanced regulation of off-target effects will overcome the current challenges of this exciting approach in the field of cancer prevention and therapy.

Dietary lipids modulate the expression of miR-107, an miRNA that regulates the circadian system

SCOPE

The increased prevalence of cardiovascular diseases (CVDs) has been hypothesized to be the result of an increased exposure to a host of atherogenic environmental factors, paramount among them being unhealthy dietary habits. Long-chain n-3 polyunsaturated fatty acids have been shown to have cardio protective effects, partially due to their ability to regulate gene expression. In this regard, increasing attention has been devoted to the role of miRNAs as regulators of multiple metabolic pathways whose deregulation has been associated with CVD risk.

METHODS AND RESULTS

In this work, we investigated whether miRNA expression was regulated by docosahexanoic acid, conjugated linoleic acid, and cholesterol in Caco-2 cells. The modulated miRNAs, miR-107 was differentially expressed by all treatments and this modulation was independent of its hosting gene, PANK1, possibly through its own promoter, which contains binding sites for metabolically relevant transcription factors. Among the putative target genes of miR-107, we found some genes with key roles in circadian rhythm. Specifically, we demonstrated that binding of miR-107 to the CLOCK gene results in the deregulation of the circadian rhythm of the cells.

CONCLUSION

Since chronodisruption has been linked to metabolic disorders such as type 2 diabetes, atherosclerosis, obesity, and CVD, our findings suggests that miR-107 could represent a new approach for pharmacological treatment of these diseases.

Enhanced anticancer properties of lomustine in conjunction with docosahexaenoic acid in glioblastoma cell lines

OBJECT

Glioblastoma is a rapidly infiltrating tumor that consistently rematerializes despite various forms of aggressive treatment. Brain tumors are commonly treated with alkylating drugs, such as lomustine, which are chemotherapeutic agents. Use of these drugs, however, is associated with serious side effects. To reduce the side effects, one approach is to combine lower doses of chemotherapeutic drugs with other nontoxic anticancer agents. In this study, using glioblastoma cell lines, the authors investigated the anticancer effects of lomustine, alone and in combination with docosahexaenoic acid (DHA), an omega-3 polyunsaturated fatty acid normally abundant in the brain and known for its anticancer potential.

METHODS

Cells were cultured from 3 human-derived tumor cell lines (U87-MG, DB029, and MHBT161) and supplemented with either DHA or lomustine to determine the growth inhibitory potential using WST-1, a mitochondrial functional indicator. Human-derived cerebral cortex microvascular endothelial cells served as a normal phenotypic control. Cellular incorporation of DHA was analyzed by gas chromatography. Using flow cytometric analysis, the DHA and/or lomustine effect on induction of apoptosis and/or necrosis was quantified; subsequently, the DHA and lomustine effect on cell cycle progression was also assessed. Western blot analysis confirmed the role of downstream cellular targets.

RESULTS

U87-MG growth was inhibited with the supplementation of either DHA (ED50 68.3 μM) or lomustine (ED50 68.1 μM); however, growth inhibition was enhanced when U87-MG cells were administered equimolar doses of each compound, resulting in nearly total growth inhibition at 50 μM. Gas chromatography analysis of the fatty acid profile in DHA-supplemented U87-MG cells resulted in a linear dose-dependent increase in DHA incorporation (< 60 μM). The combination of DHA and lomustine potently induced U87-MG apoptosis and necrosis as indicated by flow cytometric analysis. Activation of caspase-3 and poly (ADP-ribose) polymerase (PARP) was evident in lomustine-treated U87-MG cells, although this activation did not appear to be dependent on DHA supplementation. Additionally, lomustine-treated cells' growth arrested in the G2/M cell cycle stage, regardless of the presence of DHA. Similar to the U87-MG observations, the combination of DHA and lomustine resulted in growth inhibition of 2 additional human-derived glioblastoma cell lines, DB029 and MHBT161. Importantly, in primary human-derived cerebral cortex endothelial cells, this combination was only growth inhibitory (40.8%) at the highest dose screened (100 μM), which indicates a certain degree of selectivity toward glioblastoma.

CONCLUSIONS

Taken together, these data suggest a potential role for a combination therapy of lomustine and DHA for the treatment of glioblastomas.

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

In the present study, we investigated the influence of extracts from Salix spp. honey (ESH), beebread (EBB), and royal jelly (ERJ) with and without temozolomide (TMZ) on cell lines derived from a patient with diffuse astrocytoma (DASC), human glioblastoma multiforme (U87MG), and normal human astroglia (SVGp12). DASC was identified by immunocytochemistry. TMZ (20 μM) in combination with ESH (30 μg/mL), EBB (50 μg/mL), and ERJ (30 μg/mL) has stronger cytotoxic activity on U87MG cells after 72 h (20.0, 26.5, and 29.3% of control, respectively) than TMZ alone (about 6% of control). An increase of the cytotoxic effect and inhibition of DNA synthesis in SVGp12 were detected after administering TMZ with the studied extracts. NF-κB p50 subunit was reduced in U87MG cells after treatment with ESH (70.9%) and ESH + TMZ (74.7%). A significant decline of MMP-9 and MMP-2 secretion in cultured U87MG was detected after incubation with EBB (42.9% and 73.0%, respectively) and EBB + TMZ (38.4% and 68.5%, respectively). In conclusion, the use of bee products may increase the cytotoxic effect of TMZ in U87MG but also in SVGp12 cell line. It is important to note that the U87MG cells were sensitive to natural bee products, although there was no influence of natural bee products on the DASC cells.

Diet composition transiently modulates proliferative and potency features of human cord blood-derived mesenchymal stem cells

Mesenchymal stem cells (MSC) emerged in the last few years as a promise in regenerative medicine and have been actively tested in several clinical trials worldwide. However, the lack of common standards and a precise definition of MSC preparations remain a major obstacle in research and application. In this study, we compared the effects during culture of two different MSC commercial media (aMEM and SPE-IV) on the proliferative capacities, phenotypic and molecular features in human cord blood derived-MSC lines. Moreover, as miRNA are markers of stem cell multipotency and regulators of somatic cell reprogramming, we performed a miRNome analysis in both conditions. As a result, we observed that SPE-IV promoted a faster growth and modulated stemness and proliferation associated genes such as PDGFRB, p16 and p21. Notably, in aMEM miR-335 and miR-302b, both proposed as putative stemness markers, were upregulated together with miRNAs reported to decrease adipo- and osteogenesis confirming the observed reduced differentiation potential after growth in this condition. Intriguingly, phenotypic divergences were entirely due to culturing conditions and, most importantly, completely transitory since, after medium switch, the cells were able to revert their signatures. Thus, it emerges as crucial keeping constant the experimental settings, starting from culturing conditions, to avoid misleading characterization of stemness and/or potency markers when the eventual goal is unequivocal definition of such parameters for future clinical choice.

Combination of unsaturated fatty acids and ionizing radiation on human glioma cells: cellular, biochemical and gene expression analysis

Background

Based on previous observations a potential resort in the therapy of the particularly radioresistant glioma would be its treatment with unsaturated fatty acids (UFAs) combined with irradiation.

Methods

We evaluated the effect of different UFAs (arachidonic acid (AA), docosahexaenoic acid (DHA), gamma-linolenic acid (GLA), eicosapentaenoic acid (EPA) and oleic acid (OA)) on human U87 MG glioma cell line by classical biochemical end-point assays, impedance-based, real-time cellular and holographic microscopic analysis. We further analyzed AA, DHA, and GLA at morphological, gene and miRNA expression level.

Results

Corresponding to LDH-, MTS assays and real-time cytoxicity profiles AA, DHA, and GLA enhanced the radio sensitivity of glioma cells. The collective application of polyunsaturated fatty acids (PUFAs) and irradiation significantly changed the expression of EGR1, TNF-α, NOTCH1, c-MYC, TP53, HMOX1, AKR1C1, NQO1, while up-regulation of GADD45A, EGR1, GRP78, DDIT3, c-MYC, FOSL1 were recorded both in response to PUFA treatment or irradiation alone. Among the analyzed miRNAs miR-146 and miR-181a were induced by DHA treatment. Overexpression of miR-146 was also detected by combined treatment of GLA and irradiation.

Conclusions

Because PUFAs increased the radio responsiveness of glioma cells as assessed by biochemical and cellular assays, they might increase the therapeutic efficacy of radiation in treatment of gliomas. We demonstrated that treatment with DHA, AA and GLA as adjunct to irradiation up-regulated the expression of oxidative-stress and endoplasmic reticulum stress related genes, and affected NOTCH1 expression, which could explain their additive effects.

Electronic supplementary material

The online version of this article (doi:10.1186/1476-511X-13-142) contains supplementary material, which is available to authorized users.

MicroRNAs associated with ischemia-reperfusion injury and cardioprotection by ischemic pre- and postconditioning: protectomiRs

We aimed to characterize early changes in microRNA expression in acute cardioprotection by ischemic pre- and postconditioning in rat hearts. Hearts isolated from male Wistar rats were subjected to 1) time-matched nonischemic perfusion, 2) ischemia-reperfusion (30 min of coronary occlusion and 120 min of reperfusion), 3) preconditioning (3 × 5 min of coronary occlusion) followed by ischemia-reperfusion, or 4) ischemia-reperfusion with postconditioning (6 × 10 s of global ischemia-reperfusion at the onset of reperfusion). Infarct size was significantly reduced by both interventions. Of 350 different microRNAs assessed by microarray analysis, 147-160 microRNAs showed detectable expression levels. Compared with microRNA alterations induced by ischemia-reperfusion versus time-matched nonischemic controls, five microRNAs were significantly affected by both pre- and postconditioning (microRNA-125b*, microRNA-139-3p, microRNA-320, microRNA-532-3p, and microRNA-188), four microRNAs were significantly affected by preconditioning (microRNA-487b, microRNA-139-5p, microRNA-192, and microRNA-212), and nine microRNAs were significantly affected by postconditioning (microRNA-1, microRNA let-7i, microRNA let-7e, microRNA let-7b, microRNA-181a, microRNA-208, microRNA-328, microRNA-335, and microRNA-503). Expression of randomly selected microRNAs was validated by quantitative real-time PCR. By a systematic comparison of the direction of microRNA expression changes in all groups, we identified microRNAs, specific mimics, or antagomiRs that may have pre- and postconditioning-like cardioprotective effects (protectomiRs). Transfection of selected protectomiRs (mimics of microRNA-139-5p, microRNA-125b*, microRNA let-7b, and inhibitor of microRNA-487b) into cardiac myocytes subjected to simulated ischemia-reperfusion showed a significant cytoprotective effect. This is the first demonstration that the ischemia-reperfusion-induced microRNA expression profile is significantly influenced by both pre- and postconditioning, which shows the involvement of microRNAs in cardioprotective signaling. Moreover, by analysis of microRNA expression patterns in cardioprotection by pre- and postconditioning, specific protectomiRs can be revealed as potential therapeutic tools for the treatment of ischemia-reperfusion injury.

Docosahexaenoic acid modulates the enterocyte Caco-2 cell expression of microRNAs involved in lipid metabolism

Consumption of the long-chain ω-3 (n-3) polyunsaturated fatty acid docosahexaenoic acid (DHA) is associated with a reduced risk of cardiovascular disease and greater chemoprevention. However, the mechanisms underlying the biologic effects of DHA remain unknown. It is well known that microRNAs (miRNAs) are versatile regulators of gene expression. Therefore, we aimed to determine if the beneficial effects of DHA may be modulated in part through miRNAs. Loss of dicer 1 ribonuclease type III (DICER) in enterocyte Caco-2 cells supplemented with DHA suggested that several lipid metabolism genes are modulated by miRNAs. Analysis of miRNAs predicted to target these genes revealed several miRNA candidates that are differentially modulated by fatty acids. Among the miRNAs modulated by DHA were miR-192 and miR-30c. Overexpression of either miR-192 or miR-30c in enterocyte and hepatocyte cells suggested an effect on the expression of genes related to lipid metabolism, some of which were confirmed by endogenous inhibition of these miRNAs. Our results show in enterocytes that DHA exerts its biologic effect in part by regulating genes involved in lipid metabolism and cancer. Moreover, this response is mediated through miRNA activity. We validate novel targets of miR-30c and miR-192 related to lipid metabolism and cancer including nuclear receptor corepressor 2, isocitrate dehydrogenase 1, DICER, caveolin 1, ATP-binding cassette subfamily G (white) member 4, retinoic acid receptor β, and others. We also present evidence that in enterocytes DHA modulates the expression of regulatory factor X6 through these miRNAs. Alteration of miRNA levels by dietary components in support of their pharmacologic modulation might be valuable in adjunct therapy for dyslipidemia and other related diseases.

Polyunsaturated fatty acids and gliomas: a critical review of experimental, clinical, and epidemiologic data

Certain polyunsaturated fatty acids (PUFAs) called essential fatty acids (EFAs) cannot be biosynthesized by the body and hence, need to be obtained from diet. These PUFAs and their metabolites have multiple physiological functions that are altered in tumor cells due to a decreased expression of Δdelta-6-desaturase, which is an essential step in their metabolism. As a result, tumor cells would be protected from the toxic effect caused by free radicals, one product of EFA metabolism. EFAs have been proposed to have therapeutic potential in the treatment of glioblastoma. Gliomas are the most common primary tumors of the central nervous system in children and adults. High-grade gliomas remain a therapeutic challenge in neuro-oncology because there is no treatment that achieves a significant improvement in survival. Novel therapeutic strategies that use PUFAs for the treatment of gliomas have been assessed in cell cultures, rodent glioma models, and humans, with encouraging results. Here we review the latest progress made in the field.

Lipid droplet binding thalidomide analogs activate endoplasmic reticulum stress and suppress hepatocellular carcinoma in a chemically induced transgenic mouse model

Background

Hepatocellular carcinoma (HCC) is the most frequent and aggressive primary tumor of the liver and it has limited treatment options.

Results

In this study, we report the in vitro and in vivo effects of two novel amino-trifluoro-phtalimide analogs, Ac-915 and Ac-2010. Both compounds bind lipid droplets and endoplasmic reticulum membrane, and interact with several proteins with chaperone functions (HSP60, HSP70, HSP90, and protein disulfide isomerase) as determined by affinity chromatography and resonant waveguide optical biosensor technology. Both compounds inhibited protein disulfide isomerase activity and induced cell death of different HCC cells at sub or low micromolar ranges detected by classical biochemical end-point assay as well as with real-time label-free measurements. Besides cell proliferation inhibiton, analogs also inhibited cell migration even at 250 nM. Relative biodistribution of the analogs was analysed in native tissue sections of different organs after administration of drugs, and by using fluorescent confocal microscopy based on the inherent blue fluorescence of the compounds. The analogs mainly accumulated in the liver. The effects of Ac-915 and Ac-2010 were also demonstrated on the advanced stages of hepatocarcinogenesis in a transgenic mouse model of N-nitrosodiethylamine (DEN)-induced HCC. Significantly less tumor development was found in the livers of the Ac-915- or Ac-2010-treated groups compared with control mice, characterized by less liver tumor incidence, fewer tumors and smaller tumor size.

Conclusion

These results imply that these amino-trifluoro-phthalimide analogs could serve potent clinical candidates against HCC alone or in combination with dietary polyunsaturated fatty acids.

Chronic administration of proanthocyanidins or docosahexaenoic acid reverses the increase of miR-33a and miR-122 in dyslipidemic obese rats

miR-33 and miR-122 are major regulators of lipid metabolism in the liver, and their deregulation has been linked to the development of metabolic diseases such as obesity and metabolic syndrome. However, the biological importance of these miRNAs has been defined using genetic models. The aim of this study was to evaluate whether the levels of miR-122 and miR-33a in rat liver correlate with lipemia in nutritional models. For this purpose, we analyzed the levels of miRNA-33a and miR-122 in the livers of dyslipidemic cafeteria diet-fed rats and of cafeteria diet-fed rats supplemented with proanthocyanidins and/or ω-3 PUFAs because these two dietary components are well-known to counteract dyslipidemia. The results showed that the dyslipidemia induced in rats that were fed a cafeteria diet resulted in the upregulation of miR-33a and miR-122 in the liver, whereas the presence of proanthocyanidins and/or ω-3 PUFAs counteracted the increase of these two miRNAs. However, srebp2, the host gene of miR-33a, was significantly repressed by ω-3 PUFAs but not by proanthocyanidins. Liver mRNA levels of the miR-122 and miR-33a target genes, fas and pparβ/δ, cpt1a and abca1, respectively, were consistent with the expression of these two miRNAs under each condition. Moreover, the miR-33a and abca1 levels were also analyzed in PBMCs. Interestingly, the miR-33a levels evaluated in PBMCs under each condition were similar to the liver levels but enhanced. This demonstrates that miR-33a is expressed in PBMCs and that these cells can be used as a non-invasive way to reflect the expression of this miRNA in the liver. These findings cast new light on the regulation of miR-33a and miR-122 in a dyslipidemic model of obese rats and the way these miRNAs are modulated by dietary components in the liver and in PBMCs.

Mechanistic insights into the role of microRNAs in cancer: influence of nutrient crosstalk

A plethora of studies have described the disruption of key cellular regulatory mechanisms involving non-coding RNAs, specifically microRNAs (miRNA) from the let-7 family, the miR-17 family, miR-21, miR-143, and the miR-200 family, which contribute to aberrant signaling and tumor formation. Certain environmental factors, such as bioactive dietary agents, e.g., folate, curcumin, polyunsaturated fatty acids, are also thought to impact the progression and severity of cancer. In terms of the chemoprotective mechanisms of action, these bioactive dietary agents appear to act, in part, by modulating tissue levels of miR-16, miR-17 family, miR-26b, miR-106b, and miR-200 family miRNAs and their target genes. However, the mechanisms of nutrient action are not yet fully understood. Therefore, additional characterization of the putative underlying mechanisms is needed to further our understanding of the biology, early diagnosis, prevention, and the treatment of cancer. For the purpose of elucidating the epigenetic landscape of cancer, this review will summarize the key findings from recent studies detailing the effect of bioactive dietary agents on miRNA regulation in cancer.

Molecular targets of omega 3 and conjugated linoleic Fatty acids - "micromanaging" cellular response

Essential fatty acids cannot be synthesized de novo by mammals and need to be ingested either with the diet or through the use of supplements/functional foods to ameliorate cardiovascular prognosis. This review focus on the molecular targets of omega 3 fatty acids and conjugated linoleic acid, as paradigmatic molecules that can be exploited both as nutrients and as pharmacological agents, especially as related to cardioprotection. In addition, we indicate novel molecular targets, namely microRNAs that might contribute to the observed biological activities of such essential fatty acids.