Activation of the EIF2α/ATF4 and ATF6 Pathways in DU-145 Cells by Boric Acid at the Concentration Reported in Men at the US Mean Boron Intake

Boric Acid Alleviates Lipopolysaccharide-Induced Acute Lung Injury in Mice

Acute lung injury (ALI) poses a significant medical challenge due to its widespread occurrence and high mortality rates. Despite extensive efforts, current clinical interventions for ALI have shown limited success. Inflammation plays a central role within ALI progress, and boric acid (BA) has demonstrated anti-inflammatory properties both in vitro and in vivo. However, its potential to mitigate lipopolysaccharide (LPS)-induced ALI remains an area awaiting exploration in research. To bridge this research gap, we created a mouse model of ALI induced by intraperitoneal LPS injection. We employed a comprehensive set of evaluation criteria, including H&E staining, wet/dry ratio measurement, malondialdehyde (MDA)/superoxide dismutase (SOD) the oxidative stress-related biomarkers, assessment of alveolar edema, hemorrhage, inflammatory cell infiltration, and examination of thickened alveolar septum to quantify lung injury. Additionally, we measured inflammatory cytokine levels using ELISA and assessed Nrf2 and HO-1 expressions through western blotting and quantitative real-time PCR (RT-PCR). ER stress-related markers (GRP78, CHOP) were analyzed through western blot analysis. Our findings revealed that prophylactic treatment with BA effectively attenuated LPS-induced ALI, as supported by improved pathological alterations, decreased total protein concentration in bronchoalveolar lavage fluid (BALF), and reduced pulmonary edema. Furthermore, BA exhibited anti-inflammatory properties by suppressing inflammatory cytokines within the lung tissue. BA ingestion caused upregulation in SOD and a decrease in MDA contents in lung tissue homogenates. BA downregulated the levels of GRP78 and CHOP compared to the LPS group. Remarkably, BA also upregulated transcription and protein expression of Nrf2 and HO-1 compared to the LPS group. In conclusion, our study highlights BA's potential as a novel promising prophylactic agent for LPS-induced ALI, offering avenue for improving clinical management of this condition.

Borax affects cellular viability by inducing ER stress in hepatocellular carcinoma cells by targeting SLC12A5

Hepatocellular carcinoma (HCC) presents a persistent challenge to conventional therapeutic approaches. SLC12A5 is implicated in an oncogenic capacity and facilitates the progression of cancer. The objective of this investigation is to scrutinize the inhibitory effects of borax on endoplasmic reticulum (ER)-stress and apoptosis mediated by SLC12A5 in HepG2 cells. Initially, we evaluated the cytotoxic impact of borax on both HL-7702 and HepG2 cell lines. Subsequently, the effects of borax on cellular morphology and the cell cycle of these lines were examined. Following this, we explored the impact of borax treatment on the mRNA and protein expression levels of SLC12A5, C/EBP homologous protein (CHOP), glucose-regulated protein-78 (GRP78), activating transcription factor-6 (ATF6), caspase-3 (CASP3), and cytochrome c (CYC) in these cellular populations. The determined IC50 value of borax for HL-7702 cells was 40.8 mM, whereas for HepG2 cells, this value was 22.6 mM. The concentrations of IC50 (22.6 mM) and IC75 (45.7 mM) of borax in HepG2 cells did not manifest morphological aberrations in HL-7702 cells. Conversely, these concentrations in HepG2 cells induced observable morphological and nuclear abnormalities, resulting in cell cycle arrest in the G1/G0 phase. Additionally, the levels of SLC12A5, ATF6, CHOP, GRP78, CASP3, and CYC were elevated in HepG2 cells in comparison to HL-7702 cells. Moreover, SLC12A5 levels decreased following borax treatment in HepG2 cells, whereas ATF6, CHOP, GRP78, CASP3, and CYC levels exhibited a significant increase. In conclusion, our data highlight the potential therapeutic effects of borax through the regulation of ER stress in HCC by targeting SLC12A5.

In Vitro Effects of Boric Acid on Cell Cycle, Apoptosis, and miRNAs in Medullary Thyroid Cancer Cells

Medullary thyroid cancer (MTC) is a highly aggressive and chemotherapy-resistant cancer originating from the thyroid's parafollicular C cells. Due to its resistance to conventional treatments, alternative therapies such as boric acid have been explored. Boric acid, a boron-based compound, has shown anticarcinogenic effects, positioning it as a potential treatment option for MTC. TT medullary thyroid carcinoma cell line (TT cells) and human thyroid fibroblast (HThF cells) were utilized for the cell culture experiments. Cell viability was assessed using the 2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide (XTT) assay. Total RNA was extracted using Trizol reagent for gene expression and microRNA (miRNA) analysis via reverse transcription-polymerase chain reaction (RT-PCR). The extent of apoptosis induced by boric acid was determined using the terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay. Colony formation assays were conducted to evaluate the impact of boric acid on the colony-forming ability of MTC cells. At 48 h, 50% inhibitory concentration (IC50) of boric acid was found to be 35 μM. Treatment with boric acid resulted in significant modulation of apoptosis-related genes and miRNAs, including increased expression of phorbol-12-myristate-13-acetate-induced protein 1(NOXA), apoptotic protease activating factor 1 (APAF-1), Bcl-2-associated X protein (Bax), caspase-3, and caspase-9. In contrast, the expression of B cell lymphoma 2 (Bcl2), B cell lymphoma- extra-large (Bcl-xl), and microRNA-21 (miR-21), which are linked to the aggressiveness of MTC, was significantly reduced. The TUNEL assay indicated a 14% apoptosis rate, and there was a 67.9% reduction in colony formation, as shown by the colony formation assay. Our study suggests that boric acid may have anticancer activity in MTC by modulating apoptotic pathways. These findings suggest that boric acid could be a potential therapeutic agent for MTC and possibly for other malignancies with similar pathogenic mechanisms.

The Rise of Boron-Containing Compounds: Advancements in Synthesis, Medicinal Chemistry, and Emerging Pharmacology

Boron-containing compounds (BCC) have emerged as important pharmacophores. To date, five BCC drugs (including boronic acids and boroles) have been approved by the FDA for the treatment of cancer, infections, and atopic dermatitis, while some natural BCC are included in dietary supplements. Boron's Lewis acidity facilitates a mechanism of action via formation of reversible covalent bonds within the active site of target proteins. Boron has also been employed in the development of fluorophores, such as BODIPY for imaging, and in carboranes that are potential neutron capture therapy agents as well as novel agents in diagnostics and therapy. The utility of natural and synthetic BCC has become multifaceted, and the breadth of their applications continues to expand. This review covers the many uses and targets of boron in medicinal chemistry.

Redox Mechanisms Underlying the Cytostatic Effects of Boric Acid on Cancer Cells-An Issue Still Open

Boric acid (BA) is the dominant form of boron in plasma, playing a role in different physiological mechanisms such as cell replication. Toxic effects have been reported, both for high doses of boron and its deficiency. Contrasting results were, however, reported about the cytotoxicity of pharmacological BA concentrations on cancer cells. The aim of this review is to briefly summarize the main findings in the field ranging from the proposed mechanisms of BA uptake and actions to its effects on cancer cells.

Boric Acid Inhibits RANKL-Stimulated Osteoclastogenesis In Vitro and Attenuates LPS-Induced Bone Loss In Vivo

Boron and boric acid (BA) can promote osteogenic differentiation and reduce bone resorption, which controls bone growth and maintenance of bone tissue. It has been reported that BA activates PERK-eIF2α signaling to induce cytoplasmic stress granules and cell senescence in human prostate DU-145 cells. However, whether BA can affect osteoclasts formation and LPS-induced inflammatory bone loss, and the role of the PERK-eIF2α pathway in the process, remains unknown. In vitro, RAW264.7 cells were pre-treated with boric acid (BA, 1, 10, 100 μmol/L) for 4 h, and then incubated with receptor activator of nuclear factor-kappaB ligand (RANKL, 50 ng/mL) in the presence or absence of BA for 5 days. CCK-8 and tartrate-resistant acid phosphatase (TRAP) were used to examine cell viability, osteoclastogenesis, and bone resorption; quantitative real-time PCR was performed to examine mRNA levels of c-Fos, nuclear factor of activated T cells, cytoplasmic 1 (NFATc1), TRAP, and cathepsin K; western blotting was used to examine protein expressions of glucose-regulated protein 78 (GRP78), protein kinase R (PKR)-like endoplasmic reticulum kinase (PERK), phosphorylated PERK (p-PERK), eukaryotic initiation factor 2α (eIF2α), and phosphorylated eIF2α (p-eIF2α). In vivo, lipopolysaccharide (LPS)-induced bone loss model in mice was established, and micro-computed tomography (micro-CT) scanning, bone biochemical analysis, and osteoclastogenic cytokines were detected to evaluate the effect of BA on LPS-induced bone loss. In our vitro results showed that BA treatment for 5 days inhibited osteoclasts formation as well as osteoclastic bone resorption in a dose-dependent manner. The expression of osteoclasts marker genes c-Fos, NFATc1, TRAP, and cathepsin K were attenuated by BA. Immunoblotting analysis demonstrated that BA attenuated RANKL-induced PERK-eIF2α pathway activation. The in vivo data indicated that BA significantly prevented lipopolysaccharide (LPS)-induced bone loss. Our findings strongly suggest that BA may be a promising agent for the treatment of bone destructive diseases caused by excessive osteoclastogenesis.

Nail Mineral Composition Changes Do Not Reflect Bone Mineral Changes Caused by Boron Supplementation

Nails have been found to be a non-invasive and readily available tissue whose mineral content can change because of a change in dietary mineral intake. Thus, this study was undertaken to determine whether boron (B) supplementation would change the concentrations of some mineral elements in nails and whether these changes correlated with changes induced in bone. Female New Zealand White rabbits (aged 8 months, 2-2.5 kg weight) were fed a grain-based, high-energy diet containing 3.88 mg B/kg. The rabbits were divided into four treatment groups: controls receiving no supplemental B (N: 7; C) and three groups supplemented with 30 mg B/L in drinking water as borax decahydrate (Na₂B₄O₇∙10H₂O, N: 10; BD), borax anhydrous (Na₂B₄O₇, N: 7; Bah), and boric acid (H₃BO₃, N: 7; BA). Boron, calcium (Ca), copper (Cu), iron (Fe), magnesium (Mg), phosphorus (P), potassium (K), sodium (Na), sulfur (S), and zinc (Zn) concentrations in nails were determined by inductively coupled plasma atomic emission spectroscopy. Parametric and non-parametric multiple group comparisons and post hoc tests were performed and whether a correlation between nail and tibia and femur mineral elements concentrations were determined. A p-value of < 0.05 was considered statistically significant. Boron was not detectable in control nails but was found in the nails of the three B supplemented groups. Boron supplementation markedly increased the Ca concentration in nails with the effect greatest in the BA and BD groups. The P and Mg concentrations also were increased by B supplementation with the effect most marked in the BA group. In contrast, B supplementation decreased the Na concentration with the effect most noticeable in the BD and Bah groups. The Zn concentration in nails was not affected by BA and BD supplementation but was decreased by Bah supplementation. Boron supplementation did not significantly affect the concentrations of Cu, Fe, Mo, K, and S in nails. No meaningful significant correlations were found between nail mineral elements and tibia and femur mineral elements found previously. Nails can be an indicator of the response to boron supplementation but are not useful to indicate changes in mineral elements in bone in response to B supplementation.

Enhancement of ferroptosis by boric acid and its potential use as chemosensitizer in anticancer chemotherapy

Ferroptosis is a form of regulated cell death (RCD) characterized by intracellular iron ion accumulation and reactive oxygen species (ROS)-induced lipid peroxidation. Ferroptosis in cancer and ferroptosis-related anticancer drugs have recently gained interest in the field of cancer treatment. Boron is an essential trace element playing an important role in several biological processes. Recent studies have described contrasting effects of boric acid (BA) in cancer cells, ranging from protective/mitogenic to damaging/antiproliferative. Interestingly, boron has been shown to interfere with critical factors involved in ferroptosis-intracellular glutathione and lipid peroxidation in the first place. Thus, the present study was aimed to verify the ability of boron to modulate the ferroptotic process in HepG2 cells, a model of hepatocellular carcinoma. Our results indicate that-when used at high, pharmacological concentrations-BA can increase intracellular ROS, glutathione, and TBARS levels, and enhance ferroptosis induced by RSL3 and erastin. Also, high BA concentrations can directly induce ferroptosis, and such BA-induced ferroptosis can add to the cytotoxic effects of anticancer drugs sorafenib, doxorubicin and cisplatin. These observations suggest that BA could be exploited as a chemo-sensitizer agent in order to overcome cancer drug resistance in selected conditions. However, the possibility of reaching suitably high concentrations of BA in the tumor microenvironment will need to be further investigated.

The Possible Protective Effect of Boric Acid in an Alkaline-Induced Corneal Neovascularization Rat Model

It is known that boric acid (BA) exerts it antioxidant and anti-inflammatory effects by activating the activating transcription factor 4 (ATF4) and nuclear factor-erythroid 2-related factor 2 (Nrf2) pathway. This pathway has been reported to control antioxidant status in the eye. The aim of this study was to investigate the possible preventive effects of boric acid administration on oxidative damage and corneal neovascularization (CNV). Sixteen adult female Wistar albino rats were divided into two groups: (I) control (n = 8); the CNV model was applied to the right eye of the rats, and the left eyes were used as healthy controls. (II) CNV + BA (n = 8): After the CNV model was applied to the right eyes, a single subconjunctival dose (0.05 mL) of 0,018 g/mL BA was injected into the right and left eyes of the rats. Biochemical, histopathological, and immunohistochemical analyses were performed. Moderate VEGF positivity was observed in the vessels of the CNV group, a decrease in vessel proliferation, and weak VEGF positivity in the CNV + BA group. The TAS level in the CNV + BA group was significantly higher than that in the other groups. The TOS level was significantly higher in all groups than it is in the control group. The OSI value was increased in all groups when compared to the control group, but only the CNV and BA groups were statistically significant. BA not only reduced alkaline-induced corneal damage histologically but also showed a protective effect on oxidative stress biochemically.

The endoplasmic reticulum stress response in prostate cancer

In order to proliferate in unfavourable conditions, cancer cells can take advantage of the naturally occurring endoplasmic reticulum-associated unfolded protein response (UPR) via three highly conserved signalling arms: IRE1α, PERK and ATF6. All three arms of the UPR have key roles in every step of tumour progression: from cancer initiation to tumour growth, invasion, metastasis and resistance to therapy. At present, no cure for metastatic prostate cancer exists, as targeting the androgen receptor eventually results in treatment resistance. New research has uncovered an important role for the UPR in prostate cancer tumorigenesis and crosstalk between the UPR and androgen receptor signalling pathways. With an improved understanding of the mechanisms by which cancer cells exploit the endoplasmic reticulum stress response, targetable points of vulnerability can be uncovered.

Transcriptome Profiling of Duodenum Reveals the Importance of Boron Supplementation in Modulating Immune Activities in Rats

As an essential trace element, appropriate boron supplementation can promote immune function of animals. To illustrate the effects of boron in a rat model, RNA-Seq was conducted for the RNA from duodenum after treatment with different concentration of boron in which boron was given in the form of boric acid. More than 47 million reads were obtained in 0, 10, and 320 mg/L boron (0, 57.21, and 1830.66 mg/L boric acid) treatment groups that produced 58 965 402, 48 607 328, and 46 760 660 clean reads, respectively. More than 95% of the clean reads were successfully matched to the rat reference genome and assembled to generate 32 662 transcripts. A total of 624 and 391 differentially expressed candidate genes (DEGs) were found between 0 vs.10 and 0 vs. 320 mg/L boron comparison groups. We also identified transcription start site, transcription terminal site, and skipped exons as the main alternative splicing events. GO annotations revealed most of DEGs were involved in the regulation of immune activity. The DEGs were enriched in influenza A, herpes simplex infection, cytosolic DNA-sensing pathway, and antigen processing and presentation signaling pathways. The expression levels of genes enriched in these signaling pathways indicate that lower doses of boron could achieve better effects on promoting immune response in the duodenum. These effects on the immune system appear to be mediated via altering the expression patterns of genes involved in the related signaling pathways in a dose-dependent pattern. These data provide more insights into the molecular mechanisms of immune regulation in rats in response to dietary boron treatment.

Borate Ameliorates Sodium Nitrite-Induced Oxidative Stress Through Regulation of Oxidant/Antioxidant Status: Involvement of the Nrf2/HO-1 and NF-κB Pathways

The widespread industrial use of nitrite in preservatives, colorants, and manufacturing rubber products and dyes increases the possibilities of organ toxicity. Lithium borate (LB) is known as an antioxidant and an oxidative stress reliever. Therefore, this study is aimed at examining the effect of LB on nitrite-induced hepatorenal dysfunction. Twenty-eight male Swiss mice were divided into four equal groups. Group 1, the control group, received saline. Group 2 received LB orally for 5 consecutive days at a dose of 15 mg/kg bw. Group 3, the nitrite group, received sodium nitrite (NaNO₂) on Day 5 (60 mg/kg bw intraperitoneally). Group 4, the protective group (LB + NaNO₂ group), received LB for 5 days and then a single dose of NaNO₂ intraperitoneally on Day 5, the same as in Groups 2 and 3, respectively. Samples of blood and kidney were taken for serum analysis of hepatorenal biomarkers, levels of antioxidants and cytokines, and the expression of genes associated with oxidative stress and inflammation. NaNO₂ intoxication increased markers of liver and kidney functions yet decreased reduced glutathione (GSH), superoxide dismutase (SOD), and catalase activities in blood. NaNO₂ also increased the expression of tumor necrosis factor (TNF-α), interleukin-1β and interleukin-6 (IL-1β and IL-6). Pre-administration of LB protected mice from oxidative stress, lipid peroxidation, and the decrease in antioxidant enzyme activity. Moreover, LB protected mice from cytokine changes, which remained within normal levels. LB ameliorated the changes induced by NaNO₂ on the mRNA of nuclear factor erythroid 2-related factor 2 (Nfr2), heme oxygenase-1 (HO-1), nuclear factor-kappa B (NF-κB), transforming growth factor-beta 2 (TGF-β2), and glutathione-S-transferase (GST) as determined using quantitative real-time PCR (qRT-PCR). These results collectively demonstrate that LB ameliorated NaNO₂-induced oxidative stress by controlling the oxidative stress biomarkers and the oxidant/antioxidant state through the involvement of the Nrf2/HO-1 and NF-κB signaling pathways.

Recombinant human growth hormone improves the immune status of rats with septic encephalopathy: The role of VEGFR2 in the prevalence of endoplasmic reticulum stress repair module

Septic encephalopathy results from the intense reaction of the immune system to infection. The role of growth hormone (GH) signaling in maintaining brain function is well established; however, the involvement of the vascular endothelial growth factor receptor-2 (VEGFR2) in the potential modulatory effect of GH on septic encephalopathy-associated endoplasmic reticulum stress (ERS) and blood-brain barrier (BBB) permeability is not well-understood. Therefore, after the induction of mid-grade sepsis by cecal ligation/perforation, rats were subcutaneously injected with recombinant human GH (rhGH)/somatropin alone or preceded by the VEGFR2 antagonist WAG-4S for 7 days. rhGH/somatropin reduced bodyweight loss and plasma endotoxin, maintained the hyperthermic state, and improved motor/memory functions. Additionally, rhGH/somatropin increased the junctional E-cadherin and β-catenin pool in the cerebral cortex to enhance the BBB competency, effects that were abolished by VEGFR2 blockade. Also, it activated cortical VEGFR2/mammalian target of the Rapamycin (mTOR) axis to mitigate ERS. The latter was reflected by the deactivation of the inositol-requiring enzyme-1α (IRE1α)/spliced X-box binding protein-1 (XBP1s) trajectory and the reduction in the protein levels of the death markers, C/EBP homologous protein (CHOP)/growth arrest and DNA damage-153 (GADD153), c-jun-N-terminal kinase (JNK), and caspase-3 with the simultaneous augmentation of expression of the unfolded protein response transducer proteinkinaseR-like ERkinase (PERK). Furthermore, rhGH/somatropin suppressed the phosphorylation of eukaryotic initiation factor-2α (eIF2α), upregulated the gene expression of activating transcription factor-4 (ATF4), GADD34, and glucose-regulated protein-78/binding immunoglobulin (GRP78/Bip). Moreover, it increased the glutathione level and reduced lipid peroxidation in the cerebral cortex. The VEGFR2 antagonist reversed the effect of rhGH/somatropin on PERK and IRE1α and boosted the apoptotic markers but neither affected p-eIF2α nor GADD34. Hence, we conclude that VEGFR2 activation by rhGH/somatropin plays a crucial role in assembling the BBB adherens junctions via its antioxidant capacity, ERS relief, and reducing endotoxemia in septic encephalopathy.

Gibberellic Acid Initiates ER Stress and Activation of Differentiation in Cultured Human Immortalized Keratinocytes HaCaT and Epidermoid Carcinoma Cells A431

Diterpenoid plant hormone gibberellic acid (GA) plays an important role in regulation of plant growth and development and is commonly used in agriculture for activation of plant growth and food production. It is known that many plant-derived compounds have miscellaneous biological effects on animals and humans, influencing specific cellular functions and metabolic pathways. However, the effect of GA on animal and human cells remains controversial. We investigated the effect of GA on cultured human cell lines of epidermoid origin-immortalized non-tumorigenic keratinocytes HaCaT and carcinoma A431 cells. We found that at a non-toxic dose, GA upregulated the expression of genes associated with the ER stress response-CHOP, sXBP1, GRP87 in both cell lines, and ATF4 predominantly in A431 cells. We also showed that GA was more effective in upregulating the production of ER stress marker GRP78, autophagy marker LC3B-II, and differentiation markers involucrin and filaggrin in A431 cells than in HaCaT. We conclude that GA induces mild ER stress in both cell lines, followed by the activation of differentiation via upregulation of autophagy. However, in comparison with immortalized keratinocytes HaCaT, GA is more effective in inducing differentiation of carcinoma A431 cells, probably due to the inherently lower differentiation status of A431 cells. The activation of differentiation in poorly differentiated and highly malignant A431 cells by GA may lower the level of malignancy of these cells and decrease their tumorigenic potential.

Borate and boric acid supplementation of drinking water alters teeth and bone mineral density and composition differently in rabbits fed a high protein and energy diet

The reported beneficial effects of boron on mineralized tissues in animals and humans vary. Thus, a study was performed to assess whether the variability was the result of different forms of boron supplementation, method of supplementation, and increased adiposity of the rabbit experimental model. Thirty-one female New Zealand White rabbits, (aged 8 months, 2-2.5 kg weight) were fed a grain-based high energy diet containing 11.76 MJ/kg (2850 kcal/kg) and 3.88 mg boron/kg. The rabbits were randomly divided into four treatment groups: Control group was not supplemented with boron (n:7; C), and three groups supplemented with 30 mg boron/L in drinking water in the forms of borax decahydrate (Na2O4B7 10H2O, n:10; BD), borax anhydrous (Na2O4B7, n:7; Bah) or boric acid (H2BO3, n:7; BA). Cone beam micro computed tomographic (micro-CT), histological and elemental analysis was used to evaluate the bones/teeth. Results of the experiments demonstrated that boron supplementation had beneficial effects on mineralized tissue but varied with the type of treatment. Mineral density of the femur was increased by the Bah and BA treatments (p < 0.001), but only BA increased mineral density in the tibia (p = 0.015). In incisor teeth, mineral density of dentin was increased by all boron treatments (p < 0.001), and mineral density of enamel was increased by the BD and Bah treatments. Mineral analysis found that all boron treatments increased the boron concentration in tibia and femur. In the tibia, both the BD and Bah treatments decreased the iron concentration, and the BD treatment decreased the magnesium concentration. Sodium and zinc concentrations in the tibia were decreased by the Bah and BA treatments. The boron treatments did not significantly affect the calcium, copper, molybdenum, potassium phosphorus, and sulfur concentrations. The findings show that boron supplementation can have beneficial effects on mineralized tissues in an animal model with increased adiposity, which is a model of increased inflammatory stress. However, this effect varies with the form of boron supplemented, the method of supplementation, and the mineralized tissue examined.

Boron as Boric Acid Induces mRNA Expression of the Differentiation Factor Tuftelin in Pre-Osteoblastic MC3T3-E1 Cells

The effects of boron on the formation and maintenance of mineralized structures at the molecular level are still not clearly defined. Thus, a study was conducted using MC3T3-E1 cells to determine whether boron affected mRNA expressions of genes associated with bone/alveolar bone formation around the teethMC3T3-E1 (clone 4) cells were cultured in media treated with boric acid at concentrations of 0, 0.1, 10, 100, or 1000 ng/ml. Total RNAs of each group were isolated on day 3. Gene expression profiles were determined by using RT² Profiler PCR micro-array that included 84 genes associated with osteogenic differentiation. Tuftelin1 mRNA expression was upregulated by all boron treatments. The upregulation was confirmed by quantitative RT-PCR using the tuftelin probe. While 100 ng/ml had no effect on the integrin-α2 (Itga2) transcript and 1 ng/ml boric acid induced Itga2 mRNA expression (2.1-fold), 0.1, 10, and 1000 ng/ml boric acid downregulated the integrin-α2 gene transcript 2.2-, 1.5-, and 2.1-fold respectively. While 0.1 ng/ml boric acid induced BMP6, increased BMP1r mRNA expression (1.5 fold) was observed in 1000 ng/ml boric acid treatment. The findings suggest that boron affects the regulation of the tuftelin1 gene in osteoblastic cells. Further studies are needed to establish that the beneficial actions of boron on alveolar bone and tooth formation and maintenance include an effect on the expression of the tuftelin1 gene.

Different Doses of β-Cryptoxanthin May Secure the Retina from Photooxidative Injury Resulted from Common LED Sources

Retinal damage associated with loss of photoreceptors is a hallmark of eye diseases such as age-related macular degeneration (AMD) and diabetic retinopathy. Potent nutritional antioxidants were previously shown to abate the degenerative process in AMD. β-Cryptoxanthin (BCX) is an essential dietary carotenoid with antioxidant, anti-inflammatory, and provitamin A activity. It is a potential candidate for developing intervention strategies to delay the development/progression of AMD. In the current study, the effect of a novel, highly purified BCX oral formulation on the rat retinal damage model was evaluated. Rats were fed with BCX for four weeks at the doses of 2 and 4 mg/kg body weight in the form of highly bioavailable oil suspension, followed by retinal damage by exposing to the bright light-emitting diode (LED) light (750 lux) for 48 hrs. Animals were sacrificed after 48 hours, and eyes and blood samples were collected and analyzed. BCX supplementations (2 and 4 mg/kg) showed improvements in the visual condition as demonstrated by histopathology of the retina and measured parameters such as total retinal thickness and outer nuclear layer thickness. BCX supplementation helped reduce the burden of oxidative stress as seen by decreased serum and retinal tissue levels of malondialdehyde (MDA) and restored the antioxidant enzyme activities in BCX groups. Further, BCX supplementation modulated inflammatory markers (IL-1β, IL-6, and NF-κB), apoptotic proteins (Bax, Bcl-2, caspase 3), growth proteins and factors (GAP43, VEGF), glial and neuronal proteins (GFAP, NCAM), and heme oxygenase-1 (HO-1), along with the mitochondrial stress markers (ATF4, ATF6, Grp78, Grp94) in the rat retinal tissue. This study indicates that oral supplementation of BCX exerts a protective effect on light-induced retinal damage in the rats via reducing oxidative stress and inflammation, also protected against mitochondrial DNA damage and cellular death.

Powerful quantifiers for cancer transcriptomics

Every day, investigators find a new link between a form of cancer and a particular alteration in the sequence or/and expression level of a key gene, awarding this gene the title of “biomarker”. The clinician may choose from numerous available panels to assess the type of cancer based on the mutation or expression regulation (“transcriptomic signature”) of “driver” genes. However, cancer is not a “one-gene show” and, together with the alleged biomarker, hundreds other genes are found as mutated or/and regulated in cancer samples. Regardless of the platform, a well-designed transcriptomic study produces three independent features for each gene: Average expression level, expression variability and coordination with expression of each other gene. While the average expression level is used in all studies to identify what genes were up-/down-regulated or turn on/off, the other two features are unfairly ignored. We use all three features to quantify the transcriptomic change during the progression of the disease and recovery in response to a treatment. Data from our published microarray experiments on cancer nodules and surrounding normal tissue from surgically removed tumors prove that the transcriptomic topologies are not only different in histopathologically distinct regions of a tumor but also dynamic and unique for each human being. We show also that the most influential genes in cancer nodules [the Gene Master Regulators (GMRs)] are significantly less influential in the normal tissue. As such, “smart” manipulation of the cancer GMRs expression may selectively kill cancer cells with little consequences on the normal ones. Therefore, we strongly recommend a really personalized approach of cancer medicine and present the experimental procedure and the mathematical algorithm to identify the most legitimate targets (GMRs) for gene therapy.

Modulation of endoplasmic reticulum stress response in gut-origin encephalopathy: Impact of vascular endothelial growth factor receptor-2 manipulation

BACKGROUND

Septic encephalopathy, the most frequent complication of sepsis, is orchestrated by a complex interplay of signals that leads to high mortality rates among intensive care unit patients. However, the role of the vascular endothelial growth factor receptor-2 (VEGFR2) in endoplasmic reticulum stress response (ERSR), during septic encephalopathy, is still elusive.

AIM

This study was aimed to examine the effect of an in-house designed/synthesized VEGFR2 antagonist, named WAG4S, on septic encephalopathy using cecal ligation and perforation (CLP).

MAIN METHODS

Rats were intraperitoneally injected with WAG-4S (1 mg/kg/d) for 7 days post-CLP.

KEY FINDINGS

In septic animals, VEGFR2 antagonism declined the expression of cortical p-VEGFR2 and p-mammalian target of rapamycin complex-1 (p-mTORC1). It also worsened the behavioral and histopathological alterations beyond CLP. However, and contrary to CLP, WAG-4S decreased the p-protein kinase R-like ER kinase (p-PERK) and eukaryotic initiation factor-2α (p-eIF2α) expression. Moreover, VEGFR2 blockade upregulated the mRNA expression of activating transcription factor-4 (ATF4), binding immunoglobulin protein/glucose-regulated protein-78 (Bip/GRP78), growth arrest and DNA damage-34 (GADD34) and spliced X-box binding protein-1 (XBP1s) above CLP. Similarly, it boosted inositol requiring enzyme-1α (IRE1α) activation and redox imbalance. In the same context, WAG-4S augmented the protein levels of CLP-induced ERSR apoptotic markers, namely C/EBP homologous protein (CHOP/GADD153), c-jun N-terminal kinase (JNK) and caspase-3.

SIGNIFICANCE

In conclusion, the PERK/eIF2α axis inhibition, during septic encephalopathy, is VEGFR2-independent, whereas the activated IRE1α/XBP1s/CHOP/JNK/caspase-3 cue promotes the ERSR execution module through VEGFR2 inhibition. This has turned VEGFR2 into a potential therapeutic target for ameliorating such an ailment.

Anticancer effect of caudatin in diethylnitrosamine‑induced hepatocarcinogenesis in rats

An overwhelming endoplasmic reticulum stress (ERS) and the following unfolded protein response (UPR) can induce hepatic inflammation, fibrosis and hepatocellular carcinoma (HCC). Caudatin, one of the species of C-21 steroidal glycosides mainly isolated from the roots of Cynanchum bungei Decne, exhibits potent anticancer activities in vivo. However, the effect of caudatin on HCC remains unclear. In the present study, a diethylnitrosamine (DEN)-induced HCC model was established. Nodules and tumors in rat livers were monitored by T2-/T1-weighted-magnetic resonance imaging (MRI) using a 1.5 T scanner. Caudatin reduced the number and size of nodules and alleviated the inflammatory foci in the liver. In addition, the hepatic pro-inflammatory levels of interleukin (IL) 6, monocyte chemoattractant protein 1 and IL-1β were decreased in caudatin-treated rats. The DEN-induced surge in malondialdehyde, aspartate aminotransferase, alanine transaminase and TBIL were alleviated following caudatin treatment. The expression of ERS chaperones glucose-regulated protein, 94 kDa, glucose-regulated protein, 78 kDa and protein disulfide-isomerase A4 and the proliferation marker Ki-67 in liver nodules were all downregulated by caudatin as demonstrated by immunohistochemistry, reverse transcription-quantitative PCR and western blot analysis. Caudatin reduced the cytoprotective ERS sensor activating transcription factor 6-mediated signal transduction and inhibited the PKR-like endoplasmic reticulum kinase/eukaryotic initiation factor 2α/activating transcription factor 4 pathway. However, the effect of caudatin on inositol requiring enzyme 1 signaling was negligible. In conclusion, restoration of the dysregulated UPR program was involved in the antitumor efficacy of caudatin without inducing cumulative hepatotoxicity.

MiR-149 attenuates endoplasmic reticulum stress-induced inflammation and apoptosis in nonalcoholic fatty liver disease by negatively targeting ATF6 pathway

This study aimed to research the effect of miR-149 on endoplasmic reticulum stress (ERS)-induced inflammation and apoptosis in non-alcoholic fatty liver disease (NAFLD). The mouse model with NAFLD was established by feeding with a high-fat diet, and the model establishment was subsequently confirmed by H&E staining and oil red O staining. MiR-149 agomir was injected into NAFLD mice to observe changes in liver tissues. After cell transfection, qRT-PCR and Western blot were performed to measure the expressions of lipid metabolism-related proteins (SCD-1, PPARα, and ABCA1), miR-149 and ATF6. Luciferase reporter gene assay was applied to verify the relationship between miR-149 and ATF6. Inflammatory factors (TNF-α, IL-1β, IL-6 and NF-κB) and apoptotic-related factors (caspase-12 and CHOP) were measured by ELISA and flow cytometry. qRT-PCR and Western blot were applied to detect expressions of ATF6 signaling pathway-related proteins (GRP94 and Akt). NAFLD progression was attenuated in mice injected with miR-149 agomir. The expression of miR-149 was reduced in liver tissues of NAFLD mice, while the expression of ATF6 was increased. Transfection of miR-149 can result in a decrease of ATF6 expression. ATF6 was a target gene of miR-149. MiR-149 could down-regulate the expressions of inflammatory factors and apoptotic-related factors. MiR-149 could down-regulate expressions of ATF6 signaling pathway-related proteins. MiR-149 alleviates ERS-induced inflammation and apoptosis by down-regulating the ATF6 signaling pathway, thus inhibiting the progression of NAFLD.

High Concentrations of Boric Acid Trigger Concentration-Dependent Oxidative Stress, Apoptotic Pathways and Morphological Alterations in DU-145 Human Prostate Cancer Cell Line

Boric acid is known to regulate the proliferation of cancer cells. Prostate cancer is among the types of cancer with high mortality in men. There are a few numbers of studies investigating the effects of boric acid on prostate cancer cells. The objective of the present study was to assess the effects of boric acid at concentrations higher than that can be achieved in blood by dietary intake on DU-145 human prostate cancer cells for 24 h. Firstly, we determined the cytotoxic activity of boric acid (0 to 12.5 mM) on DU-145 human prostate cancer cells by using 3-(4, 5-dimethylthiazol, 2-yl)-2, 5-diphenyl tetrazolium bromide (MTT) and defined the IC50 concentration of boric acid. Then, by employing the doses found in MTT, the levels of antioxidant-oxidant molecules and apoptotic proteins were measured and morphological changes were evaluated. We have concluded that boric acid caused oxidative stress, inhibition of cell growth, apoptosis, and morphological alterations in a concentration-dependent manner in DU-145 cells. Furthermore, treatments with increasing boric acid concentrations decreased the antioxidant levels in cells. We actually revealed that boric acid, known as an antioxidant, may prevent cell proliferation by acting as an oxidant in certain doses. Although the high IC50 concentration of boric acid is perceived to be negative, we think it provides important background for subsequent studies.

The Effect of Boron-Containing Nano-Hydroxyapatite on Bone Cells

Metabolic diseases or injuries damage bone structure and self-renewal capacity. Trace elements and hydroxyapatite crystals are important in the development of biomaterials to support the renewal of bone extracellular matrix. In this study, it was assumed that the boron-loaded nanometer-sized hydroxyapatite composite supports the construction of extracellular matrix by controlled boron release in order to prevent its toxic effect. In this context, boron release from nanometer-sized hydroxyapatite was calculated by ICP-MS as in large proportion within 1 h and continuing release was provided at a constant low dose. The effect of the boron-containing nanometer-sized hydroxyapatite composite on the proliferation of SaOS-2 osteoblasts and human bone marrow-derived mesenchymal stem cells was evaluated by WST-1 and compared with the effects of nano-hydroxyapatite and boric acid. Boron increased proliferation of mesenchymal stem cells at high doses and exhibited different effects on osteoblastic cell proliferation. Boron-containing nano-hydroxyapatite composites increased osteogenic differentiation of mesenchymal stem cells by increasing alkaline phosphatase activity, when compared to nano-hydroxyapatite composite and boric acid. The molecular mechanism of effective dose of boron-containing hydroxyapatite has been assessed by transcriptomic analysis and shown to affect genes involved in Wnt, TGF-β, and response to stress signaling pathways when compared to nano-hydroxyapatite composite and boric acid. Finally, a safe osteoconductive dose range of boron-containing nano-hydroxyapatite composites for local repair of bone injuries and the molecular effect profile in the effective dose should be determined by further studies to validation of the regenerative therapeutic effect window.

Contribution of the unfolded protein response to breast and prostate tissue homeostasis and its significance to cancer endocrine response

Resistant breast and prostate cancers remain a major clinical problem, new therapeutic approaches and better predictors of therapeutic response are clearly needed. Because of the involvement of the unfolded protein response (UPR) in cell proliferation and apoptosis evasion, an increasing number of publications support the hypothesis that impairments in this network trigger and/or exacerbate cancer. Moreover, UPR activation could contribute to the development of drug resistance phenotypes in both breast and prostate cancers. Therefore, targeting this pathway has recently emerged as a promising strategy in anticancer therapy. This review addresses the contribution of UPR to breast and prostate tissues homeostasis and its significance to cancer endocrine response with focus on the current progress on UPR research related to cancer biology, detection, prognosis and treatment.

Porcine circovirus type 2 ORF5 protein induces endoplasmic reticulum stress and unfolded protein response in porcine alveolar macrophages

Porcine circovirus type 2 (PCV2) is the essential infectious agent causing porcine circovirus-associated disease (PCVD) in pigs and one of the important viruses that severely jeopardize the swine husbandry industry. PCV2 elicits the unfolded protein response (UPR) via activation of the PERK pathway, and its capsid protein (Cap) has also been found to induce UPR with subsequent activation of apoptosis. The open reading frame 5 (ORF5) protein is a recently discovered non-structural protein, and its function in PCV2 pathogenesis remains unknown. The aim of this study was to determine whether the PCV2 ORF5 protein could induce endoplasmic reticulum stress (ERS) and UPR in porcine alveolar macrophages (PAMs). pEGFP-tagged ORF5 protein was transiently overexpressed in PAMs. Transmission electron microscopy (TEM) was employed to examine changes in ER morphology, and quantitative real-time PCR and western blotting analysis were used to measure UPR-related cell signaling alterations. We found that the ORF5 protein triggers swelling and degranulation of the ER and upregulates the expression of ERS markers. Further experiments demonstrated that the PCV2 ORF5 protein induces ERS and UPR via the PERK (RNA-activated protein kinase-like endoplasmic reticulum kinase), ATF6 (activating transcription factor 6) and IRE1 (inositol requiring enzyme 1) signaling pathways. Together with previous studies, we provide new information on the ERS-UPR induced by the PCV2 ORF5 protein.

Boric Acid Activation of eIF2α and Nrf2 Is PERK Dependent: a Mechanism that Explains How Boron Prevents DNA Damage and Enhances Antioxidant Status

Boron is abundant in vegetables, nuts, legumes, and fruit and intake is associated with reduced risk of cancer and DNA damage and increased antioxidant status. Blood boric acid (BA) levels are approximately 10 μM BA in men at the mean US boron intake. Treatment of DU-145 human prostate cancer cells with 10 μM BA stimulates phosphorylation of elongation initiation factor 2α (eIF2α) at Ser51 leading to activation of the eIF2α/ATF4 pathway which activates the DNA damage-inducible protein GADD34. In the present study, we used MEF WT and MEF PERK (±) cells to test the hypothesis that BA-activated eIF2α phosphorylation requires protein kinase RNA-like endoplasmic reticulum kinase (PERK) and activates Nrf2 and the antioxidant response element (ARE). BA (10 μM) increased phosphorylation of eIF2α Ser51 in MEF WT cells at 1 h, but not in MEF Perk -/- cells exposed for as long as 6 h. GCN2 kinase-dependent phosphorylation of eIF2α Ser51 was activated in MEF PERK -/- cells by amino acid starvation. Nrf2 phosphorylation is PERK dependent and when activated is translocated from the cytoplasm to the nucleus where it acts as a transcription factor for ARE. DU-145 cells were treated with 10 μM BA and Nrf2 measured by immunofluorescence. Cytoplasmic Nrf2 was translocated to the nucleus at 1.5-2 h in DU-145 and MEF WT cells, but not MEF PERK -/- cells. Real-time PCR was used to measure mRNA levels of three ARE genes (HMOX-1, NQO1, and GCLC). Treatment with 10 μM BA increased the mRNA levels of all three genes at 1-4 h in DU-145 cells and HMOX1 and GCLC in MEF WT cells. These results extend the known boric acid signaling pathway to ARE-regulated genes. The BA signaling pathway can be expressed using the schematic [BA + cADPR → cADPR-BA → [[ER]_i Ca²⁺↓] → 3 pathways: PERK/eIF2αP → pathways ATF4 and Nrf2; and [[ER]_i Ca²⁺↓] → ER stress → ATF6 pathway. This signaling pathway provides a framework that links many of the molecular changes that underpin the biological effects of boron intake.

Astragaloside IV ameliorates endoplasmic reticulum stress‑induced apoptosis of Aβ25‑35‑treated PC12 cells by inhibiting the p38 MAPK signaling pathway

Endoplasmic reticulum stress (ERS) serves a vital role in the pathological development of Alzheimer's disease (AD). ERS can promote programmed cell death (apoptosis) during AD; however, the specific molecular mechanisms that lead to ERS remain unclear. It is very important that a drug for the treatment of AD is identified. Our previous studies indicated that astragaloside IV (AST IV) has anti-inflammatory effects and helps cells resist oxidative stress. In the present study, western blotting and reverse transcription semi-quantitative polymerase chain reaction were used to detect protein and mRNA expression levels, flow cytometry was used to measure intracellular reactive oxygen species (ROS) levels, and superoxide dismutase (SOD) and malondialdehyde (MDA) activity was detected using commercially available kits. The results demonstrated that SOD activity was decreased, and MDA content, ROS levels, and the expression levels of p38 mitogen-activated protein kinase (MAPK) and ERS-associated proteins, including binding immunoglobulin protein/glucose-regulated protein and growth arrest- and DNA damage -inducible gene 153/C/EBP homologous protein, were increased in amyloid β (Aβ)_25-35-treated PC12 cells. Furthermore, to investigate the role of p38 MAPK and the effects of AST IV in an in vitro model of AD, SB203580, a p38 MAPK signaling pathway inhibitor, and AST IV were administered to Aβ_25-35-treated PC12 cells. The results revealed that AST IV protected the cells against AD. This effect may be caused by decreases in ROS levels, which may inhibit the p38 MAPK signaling pathway and thereby suppress ERS in Aβ_25-35-treated PC12 cells.

The Physiological Role of Boron on Health

Boron is an essential mineral that plays an important role in several biological processes. Boron is required for growth of plants, animals, and humans. There are increasing evidences of this nutrient showing a variety of pleiotropic effects, ranging from anti-inflammatory and antioxidant effects to the modulation of different body systems. In the past few years, the trials showed disease-related polymorphisms of boron in different species, which has drawn attention of scientists to the significance of boron to health. Low boron profile has been related with poor immune function, increased risk of mortality, osteoporosis, and cognitive deterioration. High boron status revealed injury to cell and toxicity in different animals and humans. Some studies have shown some benefits of higher boron status, but findings have been generally mixed, which perhaps accentuates the fact that dietary intake will benefit only if supplemental amount is appropriate. The health benefits of boron are numerous in animals and humans; for instance, it affects the growth at safe intake. Central nervous system shows improvement and immune organs exhibit enhanced immunity with boron supplementation. Hepatic metabolism also shows positive changes in response to dietary boron intake. Furthermore, animals and human fed diets supplemented with boron reveal improved bone density and other benefits including embryonic development, wound healing, and cancer therapy. It has also been reported that boron affects the metabolism of several enzymes and minerals. In the background of these health benefits, low or high boron status is giving cause for concern. Additionally, researches are needed to further elucidate the mechanisms of boron effects, and determine the requirements in different species.

High Doses of Boron Have No Protective Effect Against Nephrolithiasis or Oxidative Stress in a Rat Model

Boron plays roles in the metabolism of calcium, vitamin D, steroid hormones, healthy bone development, and maintenance of cell membranes. The biological effects of boron are dose-dependent but follow a U-shaped pattern, rendering it important to define the active range. The studies of Bahadoran et al. on rats and Naghii et al. on humans showed that low doses of boron (3 and 10 mg/day) prevented kidney stone formation. The aim of this study was to determine whether high doses of boron have an anti-urolithiatic or antioxidant effect on nephrolithiasis in an experimental rat model. The study was conducted on 50 adult male Wistar rats randomized to five groups. Nephrolithiasis was induced with water containing 0.75% ethylene glycol (EG) and 2% ammonium chloride (AC). This treatment was given to animals in all groups for 10 days, except the positive and negative controls. Simultaneously, groups 2, 3, and 4 were given boric acid via gavage at doses of 25, 50, and 100 mg/kg/day (equivalent to 4/8/16 mg boron respectively) as the source of boron. Animals in the negative and positive control groups were given 6 μL/g distilled water without boric acid. At day 10, intra-cardiac blood samples were drawn from all animals. The right and left kidneys were removed for biochemical and histopathological examinations, respectively. The groups were compared with respect to serum urea, creatinine, calcium, phosphorous, total antioxidant status (TAS), total oxidant status (TOS), serum paraoxonase (PON1) activity, tissue calcium and oxalate levels, and stone burden as determined by histopathological examination. Serum urea and creatinine levels were significantly higher (p < 0.001 and p < 0.05, respectively), while serum calcium and phosphorous levels were significantly lower (p < 0.001 and p < 0.001, respectively), in animals given EG/AC compared to negative controls. No significant differences were detected in serum calcium, phosphorous, urea, or creatinine levels between animals treated with boron and positive controls (p > 0.05). Serum PON1 activity was significantly lower in animals given EG/AC than in negative controls (p < 0.001), while no significant difference in serum PON1 level was detected between rats treated with boron and positive controls. No significant differences were detected in vitamin D, TAS, TOS, tissue calcium, or tissue oxalate levels among groups. No stone formation was detected on histopathological examination in negative controls. No significant differences were found in stone formation between rats treated with boron and positive controls. Based on this study, high doses of boron had no protective effect against nephrolithiasis and oxidative stress.

The Effect of Boric Acid and Borax on Oxidative Stress, Inflammation, ER Stress and Apoptosis in Cisplatin Toxication and Nephrotoxicity Developing as a Result of Toxication

The development of treatment protocols that can reduce side effects in chemotherapy applications is extremely important in terms of cancer treatment. In this context, it was aimed to investigate the effects of boric acid and borax on cisplatin toxicity (nephrotoxicity) in rats. In the experimental phase, eight groups were formed from rats. Boric acid and borax were given to the treatment groups with three different doses using gavage. On the fifth day of the study, cisplatin (10 mg/kg) was administered to all rats except the control group. At the end of the study, oxidative stress-related (GSH, MDA, PCO, GPx, 8-OHdG), inflammation-related (TNF-α, IL-1β, IL-18, MCP-1, ICAM, TGF-β), apoptosis-related (p53, caspase 1, 3, 8, 12, bcl-2, bcl-xL, NFkB), and ER stress-related (GRP78, ATF-6, PERK) basic parameters were analyzed in serum, erythrocyte, and kidney tissues. Kidney tissues were also examined by histopathological and immunohistochemical methods. Borax and boric acid at different doses decreased inflammation and oxidative stress caused by cisplatin toxicity and increased ER stress. As a result of the treatments applied to experimental animals, it was determined that boric acid and borax reduced apoptotic damage in kidney tissue, but the decrease was statistically significant only in 200 mg/kg boric acid-administered group. In the study, low anti-apoptotic effects of borate doses with the anti-inflammatory and antioxidant effect may be due to increased ER stress at the relevant doses. Further studies on the effects of boron compounds on ER stress and apoptotic mechanisms may clarify this issue. Thus, possible side effects or if there are new usage areas of borone compounds which have many usage areas in clinics can be detected.