Folic acid supplementation in vitro induces cell type–specific changes in BRCA1 and BRCA 2 mRNA expression, but does not alter DNA methylation of their promoters or DNA repair

Folic Acid Treatment Directly Influences the Genetic and Epigenetic Regulation along with the Associated Cellular Maintenance Processes of HT-29 and SW480 Colorectal Cancer Cell Lines

Simple Summary

Folic acid (FA) participates in DNA synthesis and in DNA methylation; hence, it has a dual role in established neoplasms. We aimed to observe this phenomenon on FA-treated colorectal cancer cell lines (HT-29, SW480). Our results demonstrated that the maintenance processes, namely cell proliferation, cell viability, and DNA repair, were altered in HT-29 cells for short-term FA supplementation, while genetic and epigenetic regulations of SW480 cells were also affected. Despite the fact that FA is a precursor molecule in methyl donor formation, DNA methylation alterations were observed in both directions, primarily influencing the pathways of carcinogenesis. Moreover, behind the great number of differentially expressed genes, other FA-related effects than promoter methylation were suspected. All of our results point beyond the attributes related to FA so far. The different response of the two cell lines is worth considering in clinical practice to facilitate the effectiveness of therapy in the case of tumor heterogeneity.

Abstract

Folic acid (FA) is a synthetic form of vitamin B9, generally used as a nutritional supplement and an adjunctive medication in cancer therapy. FA is involved in genetic and epigenetic regulation; therefore, it has a dual modulatory role in established neoplasms. We aimed to investigate the effect of short-term (72 h) FA supplementation on colorectal cancer; hence, HT-29 and SW480 cells were exposed to different FA concentrations (0, 100, 10,000 ng/mL). HT-29 cell proliferation and viability levels elevated after 100 ng/mL but decreased for 10,000 ng/mL FA. Additionally, a significant (p ≤ 0.05) improvement of genomic stability was detected in HT-29 cells with micronucleus scoring and comet assay. Conversely, the FA treatment did not alter these parameters in SW480 samples. RRBS results highlighted that DNA methylation changes were bidirectional in both cells, mainly affecting carcinogenesis-related pathways. Based on the microarray analysis, promoter methylation status was in accordance with FA-induced expression alterations of 27 genes. Our study demonstrates that the FA effect was highly dependent on the cell type, which can be attributed to the distinct molecular background and the different expression of proliferation- and DNA-repair-associated genes (YWHAZ, HES1, STAT3, CCL2). Moreover, new aspects of FA-regulated DNA methylation and consecutive gene expression were revealed.

New curcumin-trimesic acid cocrystal and anti-invasion activity of curcumin multicomponent solids against 3D tumor models

Curcumin (CUR) is a Biopharmaceutics Classification System (BCS) class IV drug with poor aqueous solubility and low permeability. The dissolution of CUR can be enhanced through the cocrystallization approach. In this work, we report a new cocrystal phase of CUR with trimesic acid (TMA) with the enhanced dissolution of CUR. Cytotoxicity and cell invasion assays were conducted on (2D) monolayers and three-dimensional (3D) tumor models of triple-negative breast cancer (TNBC) cells, MDA-MB-231 using the new CUR-TMA cocrystal phase along with different CUR solid forms prepared in our previous works. The cytotoxicity and internalization assays conducted on 2D monolayers indicated that all CUR multicomponent solid forms except Curcumin-Folic Acid Dihydrate (CUR-FAD) (1:1) coamorphous solid exhibited enhanced bioavailability than unprocessed CUR. Cell invasion assay conducted on 3D tumor spheroid models showed that Curcumin-Hydroxyquinol (CUR-HXQ) cocrystal completely inhibited cell invasion whereas CUR-FAD (1:1) coamorphous solid induced enhanced invasion of cells from spheroid models.

Epigenetic effect of folic acid (FA) on the gene proximal promoter area and mRNA expression of chicken B cell as antigen presenting cells

1. This study evaluated and characterised the effect of folic acid (FA) on chromosomal DNA methylation and the epigenetic result on gene expression control mechanisms in chicken B cells as a model of antigen presenting cells. 2. After FA supplementation, the methylation pattern on the proximal promoter area and mRNA expression of toll-like receptor (TLR) 2b, TLR4, B cell receptor (BCR) immunoglobulin (Ig) β and major histocompatibility complex (MHC) II β chain genes in chicken B cells was observed 3. Chicken B cell line (DT40) cultures were incubated with 0, 1.72 or 3.96 mM of FA for 4 and 8 h and samples were taken at specific time points. After 4 h of incubation, cells were challenged with 0, 1 or 10 µg/ml of lipopolysaccharide (LPS) and samples were collected 4 h post-challenge. 4. FA supplementation modified the methylation patterns of the proximal promoter regions of TLR4, Igß, and MHCII ß chain at 4 and 8 hours of incubation; however, the single CpG dinucleotide of TLR2b remained methylated regardless of the treatment. 5. A positive association was found between FA concentration and percentage DNA methylation on the promoter area of Igβ and TLR2b. However, there was a negative association between FA and MHCII β chain. 6. There were downregulatory effects in TLR4, Igß and MHCII ß chain gene expression after 8 h of incubation, nut not at 4 h. Although incubation time did not affect TLR2b gene expression, FA concentration did, whereby it increased TLR2b expression at 1.72 mM FA (P < 0.05). 7. LPS significant downregulated TLR2b expression, while an interaction between FA and LPS concentration affected TLR4 and Igβ gene expression. 8. In conclusion, the results showed that FA can have an immunomodulatory effect on chicken B cells, possibly affecting their ability to both recognise antigens through the TLR and BCR pathways, and to present it via the MHCII presentation pathway.

Genome-Protecting Compounds as Potential Geroprotectors

Throughout life, organisms are exposed to various exogenous and endogenous factors that cause DNA damages and somatic mutations provoking genomic instability. At a young age, compensatory mechanisms of genome protection are activated to prevent phenotypic and functional changes. However, the increasing stress and age-related deterioration in the functioning of these mechanisms result in damage accumulation, overcoming the functional threshold. This leads to aging and the development of age-related diseases. There are several ways to counteract these changes: 1) prevention of DNA damage through stimulation of antioxidant and detoxification systems, as well as transition metal chelation; 2) regulation of DNA methylation, chromatin structure, non-coding RNA activity and prevention of nuclear architecture alterations; 3) improving DNA damage response and repair; 4) selective removal of damaged non-functional and senescent cells. In the article, we have reviewed data about the effects of various trace elements, vitamins, polyphenols, terpenes, and other phytochemicals, as well as a number of synthetic pharmacological substances in these ways. Most of the compounds demonstrate the geroprotective potential and increase the lifespan in model organisms. However, their genome-protecting effects are non-selective and often are conditioned by hormesis. Consequently, the development of selective drugs targeting genome protection is an advanced direction.

Folic acid supplementation repressed hypoxia-induced inflammatory response via ROS and JAK2/STAT3 pathway in human promyelomonocytic cells

Hypoxia is associated with inflammation and various chronic diseases. Folic acid is known to ameliorate inflammatory reactions, but the metabolism of folic acid protecting against hypoxia-induced injury is still unclear. In our study, we examined the inflammatory signal transduction pathway in human promyelomonocytic cells (THP-1 cells) with or without treatment with folic acid under hypoxic culture conditions. Our results indicated that supplementation with folic acid significantly reduced the levels of interleukin-1β and tumor necrosis factor-α in hypoxic conditions. Treating THP-1 cells with folic acid suppressed oxidative stress and hypoxia-inducible factor-1α in a dose-dependent manner. Folic acid targeted the activation of Janus kinase 2, downregulated the phosphorylation of signal transducer and activator of transcription 3, and decreased the expression of nuclear factor-κB p65 protein in cells. However, the absence of folic acid did not make cells more vulnerable under hypoxic conditions. In conclusion, folic acid efficiently inhibited the inflammatory response of THP-1 cells under hypoxic conditions by inhibiting reactive oxygen species production and the Janus kinase 2/signal transducer and activator of transcription 3 signaling pathway. Our study supports a basis for treatment with folic acid for chronic inflammation, which correlated with hypoxia.

Folic acid modulates cancer-associated micro RNAs and inflammatory mediators in neoplastic and non-neoplastic colonic cells in a different way

SCOPE

Scientific evidence suggests that folic acid (FA) supplementation protects the healthy colonic mucosa from neoplastic transformation but may promote the progression of precancerous lesions. The underlying molecular mechanisms are not fully understood. Therefore, we explored, if high physiological FA doses provoke changes in (i) promoter-specific DNA methylation (ii) expression of cancer-associated micro RNAs (miRNAs) and (iii) inflammatory mediators in human neoplastic and non-neoplastic colonic cell lines.

METHODS AND RESULTS

The malignant and the non-malignant colonic cell lines HT29 and HCEC were adapted to different near-physiological FA concentrations. Using DNA methylation and pathway specific PCR arrays, high-physiological FA concentrations revealed no relevant impact on promoter methylation but a number of differences between the cell lines in the expression of miRNAs and inflammatory mediators. In the HCEC cell line pro-inflammatory genes were repressed and the miRNA expression remained nearly unaffected. In contrast, in the HT29 cell line tumour-suppressive miRNAs were predominantly down-regulated and the expression of genes involved in chemotaxis and immunity were modulated.

CONCLUSION

The different effects of high-physiological FA concentrations in malignant and non-malignant colonic cell lines regarding cancer-associated miRNAs and inflammatory mediators may contribute to the different effects of FA supplementation on colonic carcinogenesis.

Effects of R type and S type ginsenoside Rg3 on DNA methylation in human hepatocarcinoma cells

Ginsenoside Rg3, a bioactive constituent isolated from Panax ginseng, exhibits antitumorigenic, antioxidative, antiangiogenic, neuroprotective and other biological activities are associated with the regulation of multiple genes. DNA methylation patterns, particularly those in the promoter region, affect gene expression, and DNA methylation is catalyzed by DNA methylases. However, whether ginsenoside Rg3 affects DNA methylation is unknown. High performance liquid chromatography assay, MspI/HpaII polymerase chain reaction (PCR) and reverse transcription‑quantitative PCR were performed to assess DNA methylation. It was demonstrated that 20(S)‑ginsenoside Rg3 treatment resulted in increased inhibition of cell growth, compared with treatment with 20(R)‑ginsenoside Rg3 in the human HepG2 hepatocarcinoma cell line. It was additionally revealed that treatment with 20(S)‑ginsenoside Rg3 reduced global genomic DNA methylation, altered cystosine methylation of the promoter regions of P53, B cell lymphoma 2 and vascular endothelial growth factor, and downregulated the expression of DNA methyltransferase (DNMT) 3a and DNMT3b more than treatment with 20(R)‑ginsenoside Rg3 in HepG2 cells. These results revealed that the modulation of DNA methylation may be important in the pharmaceutical activities of ginsenoside Rg3.

Effects of maternal folic acid supplementation on gene methylation and being small for gestational age

BACKGROUND

Being small for gestational age (SGA), a foetal growth abnormality, has a long-lasting impact on childhood health. Its aetiology and underlying mechanisms are not well understood. Underlying epigenetic changes of imprinted genes have emerged as a potential pathological pathway because they may be associated with growth, including SGA. As a common methyl donor, folic acid (FA) is essential for DNA methylation, synthesis and repair, and FA supplementation is widely recommended for women planning pregnancy. The present study aimed to investigate the inter-relationships among methylation levels of two imprinted genes [H19 differentially methylated regions (DMRs) and MEST DMRs], maternal FA supplementation and SGA.

METHODS

We conducted a case-control study. Umbilical cord blood was taken from 39 SGA infants and 49 controls whose birth weights are appropriate for gestational age (AGA). DNA methylation levels of H19 and MEST DMRs were determined by an analysis of mass array quantitative methylation.

RESULTS

Statistically significantly higher methylation levels were observed at sites 7.8, 9 and 17.18 of H19 (P = 0.030, 0.016 and 0.050, respectively) in the SGA infants compared to the AGA group. In addition, the association was stronger in male births where the mothers took FA around conception at six H19 sites (P = 0.004, 0.005, 0.048, 0.002, 0.021 and 0.005, respectively).

CONCLUSIONS

Methylation levels at H19 DMRs were higher in SGA infants compared to AGA controls. It appears that the association may be influenced by maternal peri-conception FA supplementation and also be sex-specific.