Folate receptor and human reduced folate carrier expression in HepG2 cell line exposed to fumonisin B1 and folate deficiency

Fumonisin B1 protects against long-chained polyunsaturated fatty acid-induced cell death in HepG2 cells - implications for cancer promotion

Fumonisin B1 (FB1), a food-borne mycotoxin, is a cancer promoter in rodent liver and augments proliferation of initiated cells while inhibiting the growth of normal hepatocytes by disrupting lipid biosynthesis at various levels. HepG2 cancer cells exhibited resistance to FB1-induced toxic effects presumably due to their low content of polyunsaturated fatty acids (PUFA) even though FB1-typical lipid changes were observed, e.g. significantly increased phosphatidylethanolamine (PE), decreased sphingomyelin and cholesterol content, increased sphinganine (Sa) and sphinganine/sphingosine ratio, increased C18:1ω-9, decreased C20:4ω-6 content in PE and decreased C20:4ω-6_PC/PE ratio. Increasing PUFA content of HepG2 cells with phosphatidylcholine (PC) vesicles containing C20:4ω-6 (SAPC) or C22:6ω-3 (SDPC) disrupted cell survival, cellular redox status and induced oxidative stress and apoptosis. A partially protective effect of FB1 was evident in PUFA-enriched HepG2 cells which may be related to the FB1-induced reduction in oxidative stress and the disruption of key cell membrane constituents indicative of a resistant lipid phenotype. Interactions between different ω-6 and ω-3 PUFA, membrane constituents including cholesterol, and the glycerophospho- and sphingolipids and FB1 in this cell model provide further support for the resistant lipid phenotype and its role in the complex cellular effects underlying the cancer promoting potential of the fumonisins.

Therapeutic properties, biological effects, antiliver cancer, and anticolon cancer effects of some natural compounds: A biochemical approach

Natural compounds, such as carotenoids, flavonoids, anthocyanins, or terpenoids, are physiologically active components found in plants (pigments), often known as phytochemicals or phytonutrients. The in vitro cytotoxic and anticolon cancer effects of biologically bavachin, bavachinin, artepillin C, and aromadendrin compounds against SW48, SNU-C1, COLO 205, RKO, LS411N, and SW1417 cancer cell lines were assessed. Results of enzymes and antibacterial, antifungal were in level of micromolar that is good impacts. These natural compounds may be antidiabetic, anticancer, and antibacterial candidates for drug design. IC50 results were obtained between 14-19 and 5-119 µM for α-amylase and α-glucosidase, respectively. Good inhibitor Bavachinin was detected for both enzymes (IC50 for α-amylase: 14.37 µM and IC50 for α-glucosidase: 5.27 µM). The chemical activities of aromadendrin, artepillin C, bavachin, and bavachinin against pancreatic α-amylase and α-glucosidase were assessed by conducting the molecular docking study. The chemical activities of aromadendrin, artepillin C, bavachin, and bavachinin against some of the expressed surface receptor proteins (CD44, CD47, CXCR4, EGFR, folate receptor, HER2, and endothelin receptor) in the mentioned cell lines were investigated using the molecular docking calculations. The results illustrated the atomic-level properties and potential interactions. These chemicals have high binding affinities to the enzymes and proteins, according to the docking scores. In addition, the compounds formed strong contacts with the enzymes and receptors. Thus, these compounds could be potential inhibitors for enzymes and cancer cells.

Vitamin B12 absorption and malabsorption

Vitamin B12 is assimilated and transported by complex mechanisms that involve three transport proteins, intrinsic factor (IF), haptocorrin (HC) and transcobalamin (TC) and their respective membrane receptors. Vitamin deficiency is mainly due to inadequate dietary intake in vegans, and B12 malabsorption is related to digestive diseases. This review explores the physiology of vitamin B12 absorption and the mechanisms and diseases that produce malabsorption. In the stomach, B12 is released from food carrier proteins and binds to HC. The degradation of HC by pancreatic proteases and the pH change trigger the transfer of B12 to IF in the duodenum. Cubilin and amnionless are the two components of the receptor that mediates the uptake of B12 in the distal ileum. Part of liver B12 is excreted in bile, and undergoes an enterohepatic circulation. The main causes of B12 malabsorption include inherited disorders (Intrinsic factor deficiency, Imerslund-Gräsbeck disease, Addison's pernicious anemia, obesity, bariatric surgery and gastrectomies. Other causes include pancreatic insufficiency, obstructive Jaundice, tropical sprue and celiac disease, bacterial overgrowth, parasitic infestations, Zollinger-Ellison syndrome, inflammatory bowel diseases, chronic radiation enteritis of the distal ileum and short bowel. The assessment of B12 deficit is recommended in the follow-up of subjects with bariatric surgery. The genetic causes of B12 malabsorption are probably underestimated in adult cases with B12 deficit. Despite its high prevalence in the general population and in the elderly, B12 malabsorption cannot be anymore assessed by the Schilling test, pointing out the urgent need for an equivalent reliable test.

An update on genotoxic and epigenetic studies of fumonisin B1

Fumonisins (FBs), a widespread group of mycotoxins produced by Fusarium spp., are natural contaminants in cereals and foodstuffs. Fumonisin B1 (FB1) is the most toxic and prevalent mycotoxin of this group, and it has been reported that FB1 accounts for 70-80% of FBs produced by the mycotoxigenic strains. The mode of action of FB1 depends on the structural similarity with sphinganine/sphingosine N-acyltransferase. This fact causes an accumulation of sphingoid bases and blocks the sphingolipid biosynthesis or the function of sphingolipids. Diverse toxic effects and diseases such as hepatocarcinogenicity, hepatotoxicity, nephrotoxicity, and cytotoxicity have been reported, and diseases like leukoencephalomalacia in horses and pulmonary oedema in horses and swine have been described. In humans, FBs have been associated with oesophageal cancer, liver cancer, neural tube defects, and infantile growth delay. However, despite the International Agency for Research on Cancer designated FB1 as a possibly carcinogenic to humans, its genotoxicity and epigenetic properties have not been clearly elucidated. This review aims to summarise the progress in research about the genotoxic and epigenetics effects of FB1.

Nanosized biligated metal-organic framework systems for enhanced cellular and mitochondrial sequential targeting of hepatic carcinoma

Mitochondria are reported to play a paramount role in tumorigenesis which positions them as an instrumental druggable target. However, selective drug delivery to cancer-localized mitochondria remains challenging. Herein, we report for the first time, the design, development and evaluation of a hepatic cancer-specific mitochondria-targeted dual ligated nanoscale metal-organic framework (NMOF) for cellular and mitochondrial sequential drug delivery. Surface functionalization was performed through covalent-linking of folic acid and triphenylphosphonium moieties to the aminated Zr-based MOF, NH₂-UiO-66. The characterization of the dual-ligated NMOFs using XRD, FTIR, DSC and BET analysis proved the successful conjugation process. Assessment of the drug loading and release profiling of doxorubicin (DOX)-loaded NMOF confirmed the proper retention of the drug within the NMOF porous structure alongside enhanced release in the tumor acidic environment. Furthermore, biological evaluation of the anti-tumor activity of the DOX-loaded dual-ligated NMOF on hepatocellular carcinoma affirmed the superiority of the developed system in killing the cancerous cells via apoptosis induction and halting cell cycle progression. This study attempts to underscore the promising potential of surface functionalized NMOFs in developing anticancer drug delivery systems to achieve targeted therapy.

Poly(ethylene-imine)-Functionalized Magnetite Nanoparticles Derivatized with Folic Acid: Heating and Targeting Properties

Magnetite nanoparticles (MNPs) coated by branched poly (ethylene-imine) (PEI) were synthesized in a one-pot. Three molecular weights of PEI were tested, namely, 1.8 kDa (sample MNP-1), 10 kDa (sample MNP-2), and 25 kDa (sample MNP-3). The MNP-1 particles were further functionalized with folic acid (FA) (sample MNP-4). The four types of particles were found to behave magnetically as superparamagnetic, with MNP-1 showing the highest magnetization saturation. The particles were evaluated as possible hyperthermia agents by subjecting them to magnetic fields of 12 kA/m strength and frequencies ranging between 115 and 175 kHz. MNP-1 released the maximum heating power, reaching 330 W/g at the highest frequency, in the high side of reported values for spherical MNPs. In vitro cell viability assays of MNP-1 and MNP-4 against three cell lines expressing different levels of FA receptors (FR), namely, HEK (low expression), and HeLa (high expression), and HepG2 (high expression), demonstrated that they are not cytotoxic. When the cells were incubated in the presence of a 175 kHz magnetic field, a significant reduction in cell viability and clone formation was obtained for the high expressing FR cells incubated with MNP-4, suggesting that MNP-4 particles are good candidates for magnetic field hyperthermia and active targeting.

An efficient strategy for circulating tumor cell detection: surface-enhanced Raman spectroscopy

Circulating tumor cells (CTCs) are circulating cancer cells that shed from tumor tissue into blood vessels and circulate in the blood to invade other organs, which results in fatal metastases. The CTCs in human peripheral blood are the main cause of death in most cancer patients. The detection of CTCs is of great scientific significance and clinical application value for early diagnosis, rapid evaluation of the treatment effect, in vivo drug resistance testing, individualized treatment, tumor recurrence detection and survival time judgment, etc. The surface-enhanced Raman scattering (SERS) method possesses the features of remarkable detection sensitivity, a non-destructive nature, label-free detection, a quick spectrum response and a molecular fingerprint spectrum, which give it great potential in the detection field. In the past decade, SERS technology serving as a bioprobe has been increasingly applied to detect and analyze biological components due to its unique detection advantages. Here, we present an overview of SERS biosensing substrates and recent achievements in detecting CTCs using high-sensitivity SERS platforms, and provide a unique perspective on the design and application of high-performance SERS platforms for CTC detection, especially using non-metal materials.

The Impact of Natural Dietary Compounds and Food-Borne Mycotoxins on DNA Methylation and Cancer

Cancer initiation and progression is an accumulation of genetic and epigenetic modifications. DNA methylation is a common epigenetic modification that regulates gene expression, and aberrant DNA methylation patterns are considered a hallmark of cancer. The human diet is a source of micronutrients, bioactive molecules, and mycotoxins that have the ability to alter DNA methylation patterns and are thus a contributing factor for both the prevention and onset of cancer. Micronutrients such as betaine, choline, folate, and methionine serve as cofactors or methyl donors for one-carbon metabolism and other DNA methylation reactions. Dietary bioactive compounds such as curcumin, epigallocatechin-3-gallate, genistein, quercetin, resveratrol, and sulforaphane reactivate essential tumor suppressor genes by reversing aberrant DNA methylation patterns, and therefore, they have shown potential against various cancers. In contrast, fungi-contaminated agricultural foods are a source of potent mycotoxins that induce carcinogenesis. In this review, we summarize the existing literature on dietary micronutrients, bioactive compounds, and food-borne mycotoxins that affect DNA methylation patterns and identify their potential in the onset and treatment of cancer.

When Prussian Blue Meets Porous Gold Nanoparticles: A High Signal-to-Background Surface-Enhanced Raman Scattering Probe for Cellular Biomarker Imaging

Profiling cellular biomarkers without the interference of endogenous signals could facilitate the investigation of complex intracellular biological events and provide new possibilities for precision disease diagnosis. Herein, a surface-enhanced Raman scattering (SERS) probe with a high signal-to-background ratio (SBR) for cellular biomarker imaging is constructed. The probes are prepared by incorporating Prussian blue (PB) with porous gold nanoparticles (p-Au NPs). Due to their rich built-in Raman hotspots, the p-Au NPs are excellent SERS substrates that can significantly amplify the signals of the incorporated PB. In parallel, PB shows a single peak in the cellular silent region, where the signals from the probes and endogenous molecules can be completely resolved without the need of complex spectral unmixing. As a consequence, the combination of probe signal enhancement and background elimination endows the SERS probes with an extremely high SBR. To evaluate their performance in biomarker imaging, the high-SBR SERS probes are utilized to profile folic acids at a single-cell level. This background-free, high-precision imaging technique is conducive to early diagnosis and therapeutic response of cancer that is of great importance in clinical settings.

Developmental Toxicity of Mycotoxin Fumonisin B₁ in Animal Embryogenesis: An Overview

A teratogenic agent or teratogen can disturb the development of an embryo or a fetus. Fumonisin B₁ (FB₁), produced by Fusarium verticillioides and F. proliferatum, is among the most commonly seen mycotoxins and contaminants from stale maize and other farm products. It may cause physical or functional defects in embryos or fetuses, if the pregnant animal is exposed to mycotoxin FB₁. Due to its high similarity in chemical structure with lipid sphinganine (Sa) and sphingosine (So), the primary component of sphingolipids, FB₁ plays a role in competitively inhibiting Sa and So, which are key enzymes in de novo ceramide synthase in the sphingolipid biosynthetic pathway. Therefore, it causes growth retardation and developmental abnormalities to the embryos of hamsters, rats, mice, and chickens. Moreover, maternal FB₁ toxicity can be passed onto the embryo or fetus, leading to mortality. FB₁ also disrupts folate metabolism via the high-affinity folate transporter that can then result in folate insufficiency. The deficiencies are closely linked to incidences of neural tube defects (NTDs) in mice or humans. The purpose of this review is to understand the toxicity and mechanisms of mycotoxin FB₁ on the development of embryos or fetuses.

Graphene Oxide⁻PEG⁻Protocatechuic Acid Nanocomposite Formulation with Improved Anticancer Properties

The treatment of cancer through chemotherapy is limited by its toxicity to healthy tissues and organs, and its inability to target the cancer site. In this study, we have designed an anticancer nanocomposite delivery system for protocatechuic acid (PCA) using graphene oxide–polyethylene glycol as the nanocarrier, and coated with folic acid (GO–PEG–PCA–FA) for targeting the cancer cells. The designed anticancer delivery system was found to show much better anticancer activity than the free drug PCA against liver cancer HEP-G2 cells and human colon cancer HT-29 cells; at same time, it was found to be less toxic to normal fibroblast 3T3 cells. The folate-coated anticancer delivery system was found to show better activity then the free drug and the uncoated anticancer delivery system. The in vitro release of the PCA was found to be sustained in human physiological pHs, i.e., blood pH 7.4 and intracellular lysosomal pH 4.8. These in vitro findings are highly encouraging for further in vivo evaluation studies.

Improved SERS-Active Nanoparticles with Various Shapes for CTC Detection without Enrichment Process with Supersensitivity and High Specificity

Circulating tumor cells (CTCs) have received more and more attention in medical biology and clinical practice, especially diagnosis, prognosis, and cancer treatment monitoring. The detection of CTCs within the large number of healthy blood cells is a big challenge due to their rarity, which requires a detection method with supersensitivity and high specificity. In this study, we developed three kinds of new nanoparticles with the function of surface-enhanced Raman scattering (SERS) based on spherical gold nanoparticles (AuNPs), gold nanorods (AuNRs), and gold nanostars (AuNSs) with similar particle size, similar modifications, and different shapes for CTC detection without an enrichment process from the blood. The nanoparticles possess strong SERS signal due to modification of 4-mercaptobenzoic acid (4-MBA) (i.e., Raman reporter molecule), possess excellent specificity due to stabilization of reductive bovine serum albumin (rBSA) to reduce the nonspecific catching or uptake by healthy cells in blood, and possess high sensitivity due to conjugation of folic acid (FA) (i.e., a targeted ligand) to identify CTCs. Under the optimized experimental conditions, the results of detection demonstrate that these nanoparticles could all be utilized for CTC detection without enrichment process from the blood with high specificity, and the AuNS-MBA-rBSA-FA is the best one due to its supersensitivity, whose limit of detection (i.e., 1 cell/mL) is much lower than the currently reported lowest value (5 cells/mL).

In vivo 808 nm image-guided photodynamic therapy based on an upconversion theranostic nanoplatform

A new strategy for efficient in vivo image-guided photodynamic therapy (PDT) has been demonstrated utilizing a ligand-exchange constructed upconversion-C60 nanophotosensitizer. This theranostic platform is superior to the currently reported nanophotosensitizers in (i) directly bonding photosensitizer C60 to the surface of upconversion nanoparticles (UCNPs) by a smart ligand-exchange strategy, which greatly shortened the energy transfer distance and enhanced the (1)O2 production, resulting in the improvement of the therapeutic effect; (ii) realizing in vivo NIR 808 nm image-guided PDT with both excitation (980 nm) and emission (808 nm) light falling in the biological window of tissues, which minimized auto-fluorescence, reduced light scatting and improved the imaging contrast and depth, and thus guaranteed noninvasive diagnostic accuracy. In vivo and ex vivo tests demonstrated its favorable bio-distribution, tumor-selectivity and high therapeutic efficacy. Owing to the effective ligand exchange strategy and the excellent intrinsic photophysical properties of C60, (1)O2 production yield was improved, suggesting that a low 980 nm irradiation dosage (351 J cm(-2)) and a short treatment time (15 min) were sufficient to perform NIR (980 nm) to NIR (808 nm) image-guided PDT. Our work enriches the understanding of UCNP-based PDT nanophotosensitizers and highlights their potential use in future NIR image-guided noninvasive deep cancer therapy.

Improved SERS Nanoparticles for Direct Detection of Circulating Tumor Cells in the Blood

The detection of circulating tumor cells (CTCs) in the blood of cancer patients is crucial for early cancer diagnosis, cancer prognosis, evaluation of the treatment effect of chemotherapy drugs, and choice of cancer treatment options. In this study, we propose new surface-enhanced Raman scattering (SERS) nanoparticles for the direct detection of CTCs in the blood. Under the optimized experimental conditions, our SERS nanoparticles exhibit satisfying performances for the direct detection of cancer cells in the rabbit blood. A good linear relationship is obtained between the SERS intensity and the concentration of cancer cells in the range of 5-500 cells/mL (R(2) = 0.9935), which demonstrates that the SERS nanoparticles can be used for the quantitative analysis of cancer cells in the blood and the limit of detection is 5 cells/mL, which is lowest compared with the reported values. The SERS nanoparticles also have an excellent specificity for the detection of cancer cells in the rabbit blood. The above results reinforce that our SERS nanoparticles can be used for the direct detection of CTCs in the blood with excellent specificity and high sensitivity.

Role of fumonisin B1 on DNA methylation changes in rat kidney and liver cells

CONTEXT

Fumonisin B1 (FB1) is a mycotoxin produced by Fusarium verticillioides (Sacc.) Nirenberg (Nectriaceae) mold that contaminates maize and other agricultural products. Although the effects of FB1 on sphingolipid metabolism are clear, little is known about early molecular changes associated with FB1 carcinogenicity.

OBJECTIVE

Alteration on DNA methylation, as an early event in non-genotoxic carcinogenesis, may play an important role in the mechanism of FB1 toxiciy.

MATERIALS AND METHODS

Dose-related effects of FB1 (1-50 µM for 24 h) on global DNA methylation by using high-performance liquid chromatography with UV-diode array detection (HPLC-UV/DAD) and CpG promoter methylation by methylation-specific PCR (MSP) were performed in rat liver (Clone 9) and rat kidney (NRK-52E) epithelial cells.

RESULTS

Cell viability reduction is 39% and 34% by the XTT test and LDH release in the growth medium is 32% and 26% at 200 µM of FB1 treatment in Clone 9 and NRK-52E cells, respectively. No significant dose-related effects of FB1 on global DNA methylation which ranged from 4 to 5% were observed in both cells compared with controls. Promoter regions of c-myc gene were methylated (>33%) at 10 and 50 µM of FB1 treatment in Clone 9 cells while it was unmethylated in NRK-52E cells. Promoter regions of p15 gene were unmethylated while VHL gene were found to be methylated (>33%) at 10, 25, and 50 µM and 10 and 50 µM of FB1 treatment in Clone 9 and NRK-52E cells, respectively.

DISCUSSION AND CONCLUSION

Alteration in DNA methylation might play an important role in the toxicity of FB1 in risk assessment process.

Folate and fetal programming: a play in epigenomics?

Folate plays a key role in the interactions between nutrition, fetal programming, and epigenomics. Maternal folate status influences DNA methylation, inheritance of the agouti phenotype, expression of imprinting genes, and the effects of mycotoxin FB1 on heterochromatin assembly in rodent offspring. Deficiency in folate and other methyl donors increases birth defects and produces visceral manifestations of fetal programming, including liver and heart steatosis, through imbalanced methylation and acetylation of PGC1-α and decreased SIRT1 expression, and produces persistent cognitive and learning disabilities through impaired plasticity and hippocampal atrophy. Maternal folate supplementation also produces long-term epigenomic effects in offspring, some beneficial and others negative. Deciphering these mechanisms will help understanding the discordances between experimental models and population studies of folate deficiency and supplementation.

Decreased activity of folate transporters in lipid rafts resulted in reduced hepatic folate uptake in chronic alcoholism in rats

Folic acid is an essential nutrient that is required for one-carbon biosynthetic processes and for methylation of biomolecules. Deficiency of this micronutrient leads to disturbances in normal physiology of cell. Chronic alcoholism is well known to be associated with folate deficiency, which is due in part to folate malabsorption. The present study deals with the regulatory mechanisms of folate uptake in liver during chronic alcoholism. Male Wistar rats were fed 1 g/kg body weight/day ethanol (20 % solution) orally for 3 months, and the molecular mechanisms of folate uptake were studied in liver. The characterization of the folate transport system in liver basolateral membrane (BLM) suggested it to be a carrier mediated and acidic pH dependent, with the major involvement of proton coupled folate transporter and folate binding protein in the uptake. The folate transporters were found to be associated with lipid raft microdomain of liver BLM. Moreover, ethanol ingestion decreased the folate transport by altering the Vmax of folate transport process and downregulated the expression of folate transporters in lipid rafts. The decreased transporter levels were associated with reduced protein and mRNA levels of these transporters in liver. The deranged folate uptake together with reduced folate transporter levels in lipid rafts resulted in reduced folate levels in liver and thereby to its reduced levels in serum of ethanol-fed rats. The chronic ethanol ingestion led to decreased folate uptake in liver, which was associated with the decreased number of transporter molecules in the lipid rafts that can be ascribed to the reduced synthesis of these transporters.

Time course gene expression in the one-carbon metabolism network using HepG2 cell line grown in folate-deficient medium

The integrated view of the expression of genes involved in folate-dependent one-carbon metabolism (FOCM) under folate deficiency remains unknown. Dynamics of changes in the transcriptional expression of 28 genes involved in the FOCM network were evaluated at different time points (0, 2, 4, 6, 12, 24 and 48 h) in human hepatoma HepG2 cell line. Combined experimental and computational approaches were conducted for emphasizing characteristic patterns in the gene expression changes produced by cellular folate deficiency. Bivariate analysis showed that folate deficiency (0.3 nmol/L of folate vs. 2.27 mumol/L in control medium) displayed rapid and coordinated regulation during the first 2 h with differential expression for hRfc1 (increased by 69%) and Ahcy (decreased by 437%). Density analysis through the time points gave evidence of differential expression for five genes (Ahcy, Cth, Gnmt, Mat1A, Mtrr and hRfc1). Differential expression of Ahcy, Gnmt, Mat1A and Mtrr was confirmed by time-series analysis gene expression. We also found a marked differential expression of Mtrr. Qualitative analysis of genes allowed identifying four clusters of gene that was coexpressed. Two of these clusters were consistent with specific metabolic functions as they associated genes involved in the remethylation (Mthfr and Mtrr) and in the transmethylation (Dnmt1and Dnmt3B) pathways. The study shows a strong influence of folate status on Mtrr transcription in HepG2 cells. It suggests also that folate deficiency produces transcription changes that particularly involve the clusters of genes related with the remethylation and the transmethylation pathways.