Trichostatin A, sodium butyrate, and 5-aza-2′-deoxycytidine alter the expression of glucocorticoid receptor α and β isoforms in Hut-78 T- and Raji B-lymphoma cell lines

Pharmacological Properties of Trichostatin A, Focusing on the Anticancer Potential: A Comprehensive Review

Trichostatin A (TSA), a natural derivative of dienohydroxamic acid derived from a fungal metabolite, exhibits various biological activities. It exerts antidiabetic activity and reverses high glucose levels caused by the downregulation of brain-derived neurotrophic factor (BDNF) expression in Schwann cells, anti-inflammatory activity by suppressing the expression of various cytokines, and significant antioxidant activity by suppressing oxidative stress through multiple mechanisms. Most importantly, TSA exhibits potent inhibitory activity against different types of cancer through different pathways. The anticancer activity of TSA appeared in many in vitro and in vivo investigations that involved various cell lines and animal models. Indeed, TSA exhibits anticancer properties alone or in combination with other drugs used in chemotherapy. It induces sensitivity of some human cancers toward chemotherapeutical drugs. TSA also exhibits its action on epigenetic modulators involved in cell transformation, and therefore it is considered an epidrug candidate for cancer therapy. Accordingly, this work presents a comprehensive review of the most recent developments in utilizing this natural compound for the prevention, management, and treatment of various diseases, including cancer, along with the multiple mechanisms of action. In addition, this review summarizes the most recent and relevant literature that deals with the use of TSA as a therapeutic agent against various diseases, emphasizing its anticancer potential and the anticancer molecular mechanisms. Moreover, TSA has not been involved in toxicological effects on normal cells. Furthermore, this work highlights the potential utilization of TSA as a complementary or alternative medicine for preventing and treating cancer, alone or in combination with other anticancer drugs.

Sodium butyrate improved intestinal immune function associated with NF-κB and p38MAPK signalling pathways in young grass carp (Ctenopharyngodon idella)

The present study evaluated the effect of dietary sodium butyrate (SB) supplementation on the growth and immune function in the proximal intestine (PI), middle intestine (MI) and distal intestine (DI) of young grass carp (Ctenopharyngodon idella). The fish were fed one powdery sodium butyrate (PSB) diet (1000.0 mg kg^-1 diet) and five graded levels of microencapsulated sodium butyrate (MSB) diets: 0.0 (control), 500.0, 1000.0, 1500.0 and 2000.0 mg kg^-1 diet for 60 days. Subsequently, a challenge test was conducted by injection of Aeromonas hydrophila. The results indicated that optimal SB supplementation improved the fish growth performance (percent weight gain, specific growth rate, feed intake and feed efficiency) and intestinal growth and function (intestine weight, intestine length, intestinal somatic index, folds height, trypsin, chymotrypsin, lipase and amylase activities), increased beneficial bacteria lactobacillus amount and butyrate concentration, decreased baneful bacteria Aeromonas and Escherichia coli amounts, reduced acetate and propionate concentrations, elevated lysozyme and acid phosphatase activities, increased complement (C3 and C4) and immunoglobulin M contents, and up-regulated β-defensin-1 (rather than DI), hepcidin, liver expressed antimicrobial peptide 2B (LEAP-2B) (except LEAP-2A), Mucin2, interleukin 10 (IL-10), IL-11 (rather than PI), transforming growth factor β1 (rather than PI), transforming growth factor β2 (rather than PI), IL-4/13A, IL-4/13B and inhibitor of κBα (IκBα) mRNA levels, whereas it down-regulated tumor necrosis factor α, interferon γ2, IL-1β (rather than PI), IL-6, IL-8, IL-15 (rather than PI), IL-17D (rather than PI), IL-12p35, IL-12p40 (rather than PI or MI), nuclear factor kappa B p65 (NF-κB p65) (except NF-κB p52), c-Rel (rather than PI or MI), IκB kinase β (IKKβ) (rather than PI), IKKγ (except IKKα), p38 mitogen-activated protein kinase (p38MAPK) and MAPK kinase 6 mRNA levels in three intestinal segments of young grass carp (P < 0.05), suggesting that SB supplementation improves growth and intestinal immune function of fish. Furthermore, according to the positive effect, MSB was superior to PSB on improving growth and enhancing intestinal immune function of fish, and based on feed efficiency of young grass carp, the efficacy of MSB was 3.5-fold higher than that of PSB. Finally, based on percent weight gain, protecting fish against enteritis morbidity and lysozyme activity, the optimal SB supplementation (MSB as SB source) of young grass carp were estimated to be 160.8, 339.9 and 316.2 mg kg^-1 diet, respectively.

Histone acetyltransferases and histone deacetylases in B- and T-cell development, physiology and malignancy

The development of B and T cells from hematopoietic precursors and the regulation of the functions of these immune cells are complex processes that involve highly regulated signaling pathways and transcriptional control. The signaling pathways and gene expression patterns that give rise to these developmental processes are coordinated, in part, by two opposing classes of broad-based enzymatic regulators: histone acetyltransferases (HATs) and histone deacetylases (HDACs). HATs and HDACs can modulate gene transcription by altering histone acetylation to modify chromatin structure, and by regulating the activity of non-histone substrates, including an array of immune-cell transcription factors. In addition to their role in normal B and T cells, dysregulation of HAT and HDAC activity is associated with a variety of B- and T-cell malignancies. In this review, we describe the roles of HATs and HDACs in normal B- and T-cell physiology, describe mutations and dysregulation of HATs and HDACs that are implicated lymphoma and leukemia, and discuss HAT and HDAC inhibitors that have been explored as treatment options for leukemias and lymphomas.

Prenatal xenobiotic exposure and intrauterine hypothalamus-pituitary-adrenal axis programming alteration

The hypothalamic-pituitary-adrenal (HPA) axis is one of the most important neuroendocrine axes and plays an important role in stress defense responses before and after birth. Prenatal exposure to xenobiotics, including environmental toxins (such as smoke, sulfur dioxide and carbon monoxide), drugs (such as synthetic glucocorticoids), and foods and beverage categories (such as ethanol and caffeine), affects fetal development indirectly by changing the maternal status or damaging the placenta. Certain xenobiotics (such as caffeine, ethanol and dexamethasone) may also affect the fetus directly by crossing the placenta into the fetus due to their lipophilic properties and lower molecular weights. All of these factors probably result in intrauterine programming alteration of the HPA axis, which showed a low basal activity but hypersensitivity to chronic stress. These alterations will, therefore, increase the susceptibility to adult neuropsychiatric (such as depression and schizophrenia) and metabolic diseases (such as hypertension, diabetes and non-alcoholic fatty liver disease). The "over-exposure of fetuses to maternal glucocorticoids" may be the main initiation factor by which the fetal HPA axis programming is altered. Meantime, xenobiotics can directly induce abnormal epigenetic modifications and expression on the important fetal genes (such as hippocampal glucocorticoid receptor, adrenal steroidogenic acute regulatory protein, et al) or damage by in situ oxidative metabolism of fetal adrenals, which may also be contributed to the programming alteration of fetal HPA axis.

Glucocorticoid receptor β stimulates Akt1 growth pathway by attenuation of PTEN

Glucocorticoids (GCs) are known inhibitors of proliferation and are commonly prescribed to cancer patients to inhibit tumor growth and induce apoptosis via the glucocorticoid receptor (GR). Because of alternative splicing, the GR exists as two isoforms, GRα and GRβ. The growth inhibitory actions of GCs are mediated via GRα, a hormone-induced transcription factor. The GRβ isoform, however, lacks helix 12 of the ligand-binding domain and cannot bind GCs. While we have previously shown that GRβ mRNA is responsive to insulin, the role of GRβ in insulin signaling and growth pathways is unknown. In the present study, we show that GRβ suppresses PTEN expression, leading to enhanced insulin-stimulated growth. These characteristics were independent of the inhibitory qualities that have been reported for GRβ on GRα. Additionally, we found that GRβ increased phosphorylation of Akt basally, which was further amplified following insulin treatment. In particular, GRβ specifically targets Akt1 in growth pathways. Our results demonstrate that the GRβ/Akt1 axis is a major player in insulin-stimulated growth.

Butyrate increases the formation of anti-angiogenic vascular endothelial growth factor variants in human lung microvascular endothelial cells

The primary transcript of vascular endothelial growth factor (VEGF) can be alternatively spliced and translated to pro-angiogenic and anti-angiogenic VEGF variants. We investigated the effect of sodium butyrate (NaB) on pro-angiogenic and anti-angiogenic VEGF variants production in immortalized human lung microvascular endothelial cells (HLMEC). These cells were cultured in the absence or in the presence of NaB, followed by total RNA and protein isolation. The transcript and protein levels of pro-angiogenic and anti-angiogenic VEGF variants were evaluated by reverse transcription, real-time quantitative PCR and western blot analysis. We found that NaB significantly increased the anti-angiogenic transcript and protein levels of the VEGF 121b, VEGF165b and VEGF189b variants in HLMEC cells. We did not find the pro-angiogenic VEGF189a transcript variant either in control or NaB treated cells. By contrast, the pro-angiogenic VEGF121a and VEGF165a transcript variants were present in HLMEC cells, but their levels were slightly modulated in the cells treated with NaB compared to controls. Since anti-angiogenic VEGF variants inhibit angiogenesis and tumour progression, and NaB is considered an anticancer drug, our findings may have clinical significance.

Glucocorticoid receptor alpha and beta variant expression is associated with ASF/SF2 splicing factor upregulation in HT-29 colon cancer and MCF-7 breast carcinoma cells

BACKGROUND AND AIMS

Transcriptional activity of NF-kappaB is inhibited by the liganded glucocorticoid receptor (GR), which exists mainly in two splice variants as functional GRalpha and nonfunctional GRbeta. We investigated the effect of 5-aza-2'-deoxycytidine (5-dAzaC), trichostatin A (TSA), and sodium butyrate (NaBu) on GRalpha,GRbeta and ASF/SF2 splicing factor expression in HT-29 colon and MCF-7 breast carcinoma cells.

METHODS

HT-29 and MCF-7 cells were cultured in the absence or in the presence of 5-dAzaC, TSA, and NaBu, followed by RNA and protein isolation. The transcript and protein levels of GRalpha, GRbeta ASF/SF2 were determined by reverse transcription, real-time quantitative PCR and Western blot analysis.

RESULTS

We found that 5-dAzaC, TSA, and NaBu lead to an increase in GRalpha and ASF/SF2 transcript levels and a decrease in GRbeta transcript levels in HT-29 and MCF-7 cells. The 5-dAzaC, TSA, and NaBu resulted in increased GRalpha and ASF/SF2 protein levels and GRbeta protein downregulation in HT-29 cells. The most increased GRalpha protein expression in MCF-7 cells was observed with NaBu. However, all of these compounds inhibited GRbeta protein expression in MCF-7 cells. The MCF-7 cells treated with NaBu demonstrated a remarkable increase in ASF/SF2 protein expression.

CONCLUSIONS

Because NF-kappaB is considered to be a factor in the augmentation of malignant properties of cells, treatment of tumors with 5-dAzaC, TSA, and NaBu may provide a novel approach to the enhancement of therapeutic effects of glucocorticoids in epithelial carcinomas.

5-Aza-2'-deoxycytidine increases the expression of anti-angiogenic vascular endothelial growth factor 189b variant in human lung microvascular endothelial cells

Vascular endothelial growth factor (VEGF) is involved in angiogenesis, growth, and tumour cell metastasis. VEGF is expressed as alternative splice variants, which exhibit angiogenic and anti-angiogenic properties. We determined the effect of 5-Aza-2'-deoxycytidine (5-dAzaC) DNA methyltransferase (DNMTs) inhibitor on angiogenic and anti-angiogenic VEGF variants expression in immortalized human lung microvascular endothelial cells (HLMEC). Employing reverse transcription, real-time quantitative PCR (RQ-PCR), and Western blot analysis, we determined that 5-dAzaC decreased VEGF(121a) and VEGF(165a) angiogenic, and VEGF(121b) and VEGF(165b) anti-angiogenic variants expression in HLMEC. However, this DNMTs inhibitor significantly increases expression of VEGF(189b) anti-angiogenic variant transcript and protein in HLMEC. Our results suggest that the DNMTs activity may have an influence on the expression of angiogenic and anti-angiogenic VEGF variants in human lung microvascular endothelial cells.