The effect of hesperetin on estrogen receptor gene expression and its relationship with the downstream pathways of estrogen receptor alpha

BACKGROUND

Estrogen receptor (ER) is a transcription factor that affects the expression of some genes involved in the progression and development of breast cancer (BC). Hesperetin (Hst) is a flavonoid that inhibits the proliferation of BC cells. In this study, we investigated the effect of Hst on the cell viability of MCF-7 cells and the gene expression of the ERα, ERβ, IL-6, Ps2, and Cyclin D1.

METHODS

In this study, cell viability was determined by MTT assay. The cells were seeded in RPMI-1640 medium and then exposed to different concentrations of Hst (0, 25, 50, 100, 200, and 400 µM) for 24 h, and IC50 was calculated. Real-time PCR was used to assess the expression of ERα, ERβ, pS2, Cyclin D1, and IL-6 mRNA. MCF-7 cells were seeded in RPMI-1640 medium and then exposed to different concentrations of Hst (0, 25, 50, 100, and 200 µM) for 24 h. Real-time PCR was carried out using a Step One Real-Time PCR System (ABI, USA) and Amplicon SYBR Green reagents.

RESULTS

The MTT assay revealed increased cytotoxicity with higher concentrations of Hst, and the IC50 was calculated at 200 µM. Real-time PCR analysis following treatment with Hst showed a significant increase in ERα gene expression at 25 µM of Hst and a decrease in expression at 50, 100, and 200 µM of Hst (p < 0.0001). ERβ gene expression significantly decreased across all concentrations of Hst (p < 0.0001), while IL-6 gene expression decreased significantly in all concentrations (p < 0.0001). pS2 gene expression increased significantly with all concentrations of Hst (p < 0.0001), while Cyclin D1 gene expression did not significantly decrease upon Hst exposure (p > 0.05).

CONCLUSIONS

The results of our study demonstrate that Hst has the ability to induce cell death in MCF-7 cells. Furthermore, it was observed that Hst reduces the expression of the ER gene and enhances its activity, which can affect the downstream pathways of the ER.

The effect of crocin and losartan on TGF-β gene expression and histopathology of kidney tissue in a rat model of diabetic nephropathy

Objective

Diabetic nephropathy is one of the most common microvascular complications of diabetes mellitus that finally leads to complete loss of kidney function. Therefore, this study aimed to evaluate the effect of crocin and losartan on TGF-β gene expression and histopathology of kidney tissue in a rat model of diabetic nephropathy.

Materials and Methods

Forty male Wistar rats were randomly divided into five groups (n=8): Untreated control, Diabetic (D), D + crocin, D + losartan, and D + losartan + crocin. Induction of diabetes was performed using streptozotocin (50 mg/kg/ Intraperitoneal injection). At the end of the eight-week period, the rats were sacrificed. Spectrophotometry measured serum glucose, urea, creatinine, and uric acid levels. Microalbumin and creatinine levels were measured in 24-hour urine. Real-time PCR was used to determine the relative expression of the TGF-β gene in kidney tissue. Renal tissue histopathology was also examined.

Results

The results showed that hyperglycemia increased biochemical factors associated with diabetes, TGF-β gene expression, and kidney damage. Separate treatment with crocin and losartan led to a decrease in renal function factors and TGF-β gene expression and improved kidney damage.

Conclusion

Our results showed that crocin could improve kidney function in diabetic conditions. In addition, we showed that crocin increases the effectiveness of losartan. Consequently, we suggest that crocin in combination with chemical drugs can be a potential therapeutic agent for diabetes and its complications. Nonetheless, human studies are needed to make firm findings.

Effect of crocin and losartan on biochemical parameters and genes expression of FRMD3 and BMP7 in diabetic rats

BACKGROUND

Diabetes is a multifactorial and growing disease, one of the severe complications of which is diabetic nephropathy (DN), which is the most common cause of chronic renal failure. FERM domain containing 3 (FRMD3) is responsible for maintaining the shape and integrity of nephron cells, and bone morphogenetic protein 7 (BMP7) helps maintain function and reduce kidney damage. This study aimed to evaluate the effect of crocin and losartan on biochemical parameters and the expression of FRMD3 and BMP7 genes in streptozotocin (STZ)-induced diabetic rats.

METHODS

Forty male Wistar rats were randomly divided into five experimental groups as healthy, diabetic control (D), crocin, losartan, and diabetic rats treated with losartan-crocin (n = 8). A single dose of STZ (50 mg/kg intraperitoneally injection) was used to induce diabetes. Four weeks after induction of diabetes, rats received crocin (50 mg/kg) and losartan (25 mg/kg) daily for four weeks orally. Rats were sacrificed at the end of the intervention, and blood samples were taken to determine serum levels of glucose, urea, creatinine (Cr), malondialdehyde (MDA), and thiol. Real-time polymerase chain reaction (PCR) was used to assess the expression of the FRMD3 and BMP7 genes in the kidney samples.

RESULTS

Diabetes induction increased serum levels of glucose, Cr, urea, MDA, and thiol, but decreased BMP7 and FRMD3 genes expression. Treatment with crocin and losartan decreased these biochemical parameters and increased the expression of the BMP7 and FRMD3 genes.

DISCUSSION

Crocin may be a promising therapeutic agent for preventing and improving diabetes-related kidney disease due to its antidiabetic and antioxidant properties.

Production of anti-tetanus toxin IgY and study of its protective effects in a mouse model

Tetanus is an acute and often fatal infectious disease caused by Clostridium tetani. Tetanus toxin (TT) is responsible for spastic paralysis observed in tetanus. Anti-tetanus antibodies obtained from horses and humans are the most antitoxins used for tetanus treatment, although some clinical side effects and disadvantages have been reported in their application. The aim of this study is the production of anti-TT IgY and evaluation of its protective effects in a mouse model. Anti-TT IgY was purified from the egg yolk using PEG6000 precipitation and water dilution methods, and its purity was verified by SDS-PAGE. Finally, the potency of purified anti-TT IgY in neutralizing the lethal effects of TT was studied in vivo using a mouse model. PEG6000 precipitation method had better results. Animal studies showed that the purified IgY neutralized the toxic effects of 100 MLD of TT and multiple intravenous-dose injections of anti-TT IgY also had a continuous effect of TT neutralization. The purified anti-TT IgY was effective in neutralizing the lethal activity of TT in a mouse model. Our results suggested that IgY could be an alternative therapeutic source for the management of tetanus in the future.Abbreviations Anti-TT, Anti-tetanus toxin; ELISA, Enzyme-linked immunosorbent assay; IgY, Immunoglobulin Y; MLD, Minimum lethal dose; PBS, Phosphate buffer solution; PEG, Polyethylene glycol; SDS-PAGE, Sodium dodecyl sulfate polyacrylamide gel electrophoresis; TIG, Tetanus immune globulin; TT, Tetanus toxin; WD, Water dilution; RT, Room temperature.

MicroRNA-494 induces breast cancer cell apoptosis and reduces cell viability by inhibition of nicotinamide phosphoribosyltransferase expression and activity

Breast cancer (BC) is the most prevalent cause of cancer-related death in women worldwide. BC is frequently associated with elevated levels of nicotinamide phosphoribosyltransferase (NAMPT) in blood and tumor tissue. MicroRNA-494 (miR-494) has been described to play key anti-tumor roles in human cancers. The aim of the present study was to investigate the inhibitory effect of miR-494 on NAMPT-mediated viability of BC cells. In this experimental study, MCF-7 and MDA-MB-231 cells were cultured and then transfected with miR-494 mimic, miR-494 inhibitor and their negative controls. The mRNA and protein expression of NAMPT were assessed using real-time PCR and Western blotting, respectively. Subsequently, intracellular NAD levels were determined by a colorimetric method. Finally, cell apoptosis was examined by flow cytometry. Bioinformatics evaluations predicted NAMPT as a miR-494 target gene which was confirmed by luciferase reporter assay. Our results showed an inverse relationship between the expression of miR-494 and NAMPT in both MCF-7 and MDA-MB-231 cell lines. miR-494 significantly down-regulated NAMPT mRNA and protein expression and was also able to reduce the cellular NAD content. Cell viability was decreased following miR-494 up-regulation. In addition, apoptosis was induced in MCF-7 and MDA-MB-231 cells by miR-494 mimic. Our findings indicate that miR-494 acts as a tumor suppressor and has an important effect in suppressing the growth of BC cells through NAMPT. Therefore, miR-494 might be considered as a novel therapeutic target for the management of human breast cancer.

Hesperetin is a potent bioactivator that activates SIRT1-AMPK signaling pathway in HepG2 cells

Sirtuin 1 (SIRT1) is a deacetylase enzyme that plays crucial roles in controlling many cellular processes and its downregulation has been implicated in different metabolic disorders. Recently, several polyphenols have been considered as the effective therapeutic approaches that appear to influence SIRT1. The main goal of this study was to evaluate the effect of hesperetin, a citrus polyphenolic flavonoid, on SIRT1 and AMP-activated kinase (AMPK). HepG2 cells were treated with hesperetin in the presence or absence of EX-527, a SIRT1 specific inhibitor, for 24 h. Resveratrol was used as a positive control. SIRT1 gene expression, protein level, and activity were measured by RT-PCR, Western blotting, and fluorometric assay, respectively. AMPK phosphorylation was also determined by Western blotting. Our results indicated a significant increase in SIRT1 protein level and activity as well as an induction of AMPK phosphorylation by hesperetin. These effects of hesperetin were abolished by EX-527. Furthermore, hesperetin reversed the EX-527 inhibitory effects on SIRT1 protein expression and AMPK phosphorylation. These findings suggest that hesperetin can be a novel SIRT1 activator, even stronger than resveratrol. Therefore, the current study may introduce hesperetin as a new strategy aimed at upregulation SIRT1-AMPK pathway resulting in various cellular processes regulation.

Signaling Crosstalk of FHIT, p53, and p38 in etoposide-induced apoptosis in MCF-7 cells

Fragile histidine trail (FHIT) is a tumor suppressor in response to DNA damage which has been deleted in various tumors. However, the signaling mechanisms and interactions of FHIT with regard to apoptotic proteins including p53 and p38 in the DNA damage-induced apoptosis are not well described. In the present study, we used etoposide-induced DNA damage in MCF-7 as a model to address these crosstalks. The time course study showed that the expression of FHIT, p53, and p38MAPK started after 1 hour following etoposide treatment. FHIT overexpression led to increase p53 expression, p38 activation, and augmented apoptosis following etoposide-induced DNA damage compared to wild-type cells. However, FHIT knockdown blocked p53 expression, delayed p38 activation, and completely inhibited etoposide-induced apoptosis. Inhibition of p38 activity prevented induction of p53, FHIT, and apoptosis in this model. Thus, activation of p38 upon etoposide treatment leads to increase in FHIT and p53 expression. In p53 knockdown MCF-7, the FHIT induction was hampered but p38 activation was induced in lower doses of etoposide. In p53 knockdown cells, inhibition of p38 induced FHIT expression and apoptosis. Our data demonstrated that the exposure of MCF-7 cells to etoposide increases apoptosis through a mechanism involving the activation of the p38-FHIT-p53 pathway. Moreover, our findings suggest signaling interaction for these pathways may represent a promising therapy for breast cancer.

Investigating the effect of visfatin on ERalpha phosphorylation (Ser118 and Ser167) and ERE-dependent transcriptional activity

Obesity is associated with higher postmenopausal breast cancer incidence. Visfatin level alteration is one of the mechanisms by which obesity promotes cancer. Ligand-independent activation of estrogen receptor alpha (ERα) is also associated with carcinogenesis. The activity of ERα is modulated through phosphorylation on multiple sites by a number of protein kinases. Here we investigated the effect of visfatin as a novel adipocytokine on the phosphorylation and activity of ERα in MCF-7 breast cancer cells. We showed that exogenous administration of visfatin significantly increased the phosphorylation of ERα at serine 118 (Ser118) and 167 (Ser167) residues. Visfatin-induced Ser118 phosphorylation was diminished after treatment of cells with U0126 (MEK1/2 inhibitor). Furthermore, our results showed that visfatin-induced Ser167 phosphorylation is mediated through both MAPK and PI3K/Akt signaling pathways. Inhibition of the enzymatic activity of visfatin by FK866 had no effect on phosphorylation of ERα. We also showed that visfatin enhanced the estrogen response element (ERE)-dependent activity of ER in the presence of 17-β estradiol (E2). Additional study on T47D cells showed that visfatin also increased Ser118 and Ser167 phosphorylation of ERα and enhanced ERE-dependent activity in the presence of E2 in these cells.

The Preventive Effect of L-Lysine on Lysozyme Glycation in Type 2 Diabetes

Lysozyme is a bactericidal enzyme whose structure and functions change in diabetes. Chemical chaperones are small molecules including polyamines (e.g. spermine), amino acids (e.g. L-lysine) and polyols (e.g. glycerol). They can improve protein conformation in several stressful conditions such as glycation. In this study, the authors aimed to observe the effect of L-lysine as a chemical chaperone on structure and function of glycated lysozyme. In this study, in vitro and in vivo effects of L-lysine on lysozyme glycation were investigated. Lysozyme was incubated with glucose and/or L-lysine, followed by an investigation of its structure by electrophoresis, fluorescence spectroscopy, and circular dichroism spectroscopy and also assessment of its bactericidal activity against M. lysodeikticus. In the clinical trial, patients with type 2 diabetes mellitus (T2DM) were randomly divided into two groups of 25 (test and control). All patients received metformin and glibenclamide for a three months period. The test group was supplemented with 3 g/day of L-lysine. The quantity and activity of lysozyme and other parameters were then measured. Among the test group, L-lysine was found to reduce the advanced glycation end products (AGEs) in the sera of patients with T2DM and in vitro condition. This chemical chaperone reversed the alteration in lysozyme structure and function due to glycation and resulted in increased lysozyme activity. Structure and function of glycated lysozyme are significantly improved by l-lysine; therefore it can be considered an effective therapeutic supplementation in T2DM, decreasing the risk of infection in these patients.