Hallmarks of exosomes.

Exosomes are a new horizon in modern therapy, presenting exciting new opportunities for advanced drug delivery and targeted release. Exosomes are small extracellular vesicles with a size range of 30-100 nm, secreted by all cell types in the human body and carrying a unique collection of DNA fragments, RNA species, lipids, protein biomarkers, transcription factors and metabolites. miRNAs are one of the most common RNA species in exosomes, and they play a role in a variety of biological processes including exocytosis, hematopoiesis and angiogenesis, as well as cellular communication via exosomes. Exosomes can act as cargo to transport this information from donor cells to near and long-distance target cells, participating in the reprogramming of recipient cells.

Role of exosomes and exosomal microRNAs in cancer.

A growing body of evidence indicates that exosomes play a critical role in the cell-cell communication process. Exosomes are biological nanoparticles with an average diameter of 30-100 nm in size and are produced by almost all cell types in the human body; however, cancer cells contain higher concentrations of exosomes than healthy cells. They are released into all body fluids and contain double-stranded DNA (originated from nucleus and mitochondria), a variety of RNA species, and specific protein biomarkers that can be utilized as cancer biomarkers and therapeutic targets, and lipids. Therefore, the specific exosomes secreted by tumor cells could be used to predict the existence of the presence of a tumor in cancer patients. This review summarizes the role of exosomes in cancer development and their potential utility in the clinic.

Novel miRNAs as potential biomarkers in stage II colon cancer: microarray analysis.

The aim of this study was to determine oncogenic and tumor-suppressing miRNA profiles associated with the development and progression of cancer using tumor tissues from patients with colorectal cancer (stage II) that did not show nodal spread or advanced metastasis to identify potential biomarkers. A microarray system (GeneChip miRNA 4.0 Array chip, Affymetrix) was used to determine the microRNA profiles of five patients with stage II colon cancer based on normal and colon tumor tissues. Of 32 identified miRNAs, an increase in three microRNAs (hsa-miR-4745-5p, hsa-miR-6126, and hsa-miR-1469) was observed in tumor tissues relative to that in control tissues. Additionally, this study demonstrated for the first time that the expression of the 8 miRNAs (hsa-miR-378i, hsa-miR-378a-3p, hsa-miR-378c, hsa-miR-378d, hsa-miR-378e, hsa-miR-378f, hsa-miR-378a-5p, and hsa-miR-378g) from miR-378 members among the differentially expressed miRNAs is reduced. The target genes of these downregulated miRNAs were determined by using DIANA miRPath v3. The effect of identified genes on colon cancer stage II was determined the biological process and biological pathway using Funrich Gene Enrichment. It was revealed that these miRNAs were affected the signaling pathways which control cell proliferation, cell-cell interaction, and apoptosis in stage II colon cancer. In patients with early stage II colon cancer, miR-378 can be used as a biomarker of colorectal cancer. Thus, miR-378 can facilitate treatment with early diagnosis.

Anthocyanin-rich extract from Hibiscus sabdariffa calyx counteracts UVC-caused impairments in rats.

CONTEXT: Ultraviolet radiation (UV) was reported to cause oxidative stress. Hibiscus sabdariffa L. (Malvaceae) calyx is commonly used in traditional Asian and African medicines and possesses strong antioxidant capacity due to its anthocyanin (ANTH) content. OBJECTIVE: This study researched the possible protective role of Hibiscus sabdariffa calyx extract (HSCE) in UVC exposure of rats. MATERIAL AND METHODS: Levels of serum enzymes, renal function tests, and some oxidant/antioxidant biomarkers of skin, lens, and retina tissues were monitored. Rats were exposed to UVC 4 h daily for 40 d and simultaneously received HSCE containing 2.5, 5, and 10 mg doses of ANTH in drinking water. RESULTS: Significant (p < 0.05) increases in the levels of serum aminotransferases, lactate dehydrogenase, urea, creatinine, and uric acid were noted after UVC exposure. In skin, lens, and retina tissues, total oxidant status, oxidative stress index, lipid peroxidation, and protein oxidation escalated markedly (p < 0.05) whereas total antioxidant status, reduced glutathione, and superoxide dismutase decreased dramatically (p < 0.05) related to UVC. Co-administration of HSCE with each ANTH dose significantly (p < 0.05) reversed aforementioned parameters (except total oxidant status) almost in all tissues. The LD50 of HSCE in rats was determined to be above 5000 mg/kg. DISCUSSION AND CONCLUSION: Our data revealed that HSCE has a remarkable potential to counteract UVC-caused impairments, probably through its antioxidant and free radical-defusing effects. Therefore, HSCE could be useful against some cutaneous and ocular diseases in which UV and oxidative stress have a role in the etiopathogenesis.

Decreased expression of EFS is correlated with the advanced prostate cancer.

Prostate cancer is the most frequently diagnosed malignant neoplasm in men in the developed countries. Although the progression of prostate cancer and the processes of invasion and metastasis by tumor cells are comparatively well understood, the genes involved in these processes are not fully determined. Therefore, a common area of research interest is the identification of novel molecules that are involved in these processes. In the present study, we have used in silico and experimental approaches to compare the expression of embryonal Fyn-associated substrate (EFS) between normal prostate and prostate cancer. We showed that EFS expression is remarkably downregulated in prostate cancer cells, compared to normal prostate cells. We also found that decreased expression of EFS in prostate cancer cells is due to DNA methylation. In addition, we showed that high EFS expression is important to suppress a malignant behavior of prostate cancer cells. Therefore, we suggest that EFS should be considered as a novel tumor suppressor gene in prostate cancer.

Age- and diabetes-induced regulation of oxidative protein modification in rat brain and peripheral tissues: consequences of treatment with antioxidant pyridoindole.

The increased glyco- and lipo-oxidation events are considered one of the major factors in the accumulation of non-functional damaged proteins, and the antioxidants may inhibit extensive protein modification and nitrosylated protein levels, enhancing the oxidative damage at the cellular levels in aging and diabetes. Because of its central role in the pathogenesis of age-dependent and diabetes-mediated functional decline, we compared the levels of oxidatively modified protein markers, namely AGEs (Advanced Glycation End-protein adducts), 4-HNE (4-hydroxy-nonenal-histidine) and 3-NT (3-nitrotyrosine), in different tissues of young and old rats. Separately, these three oxidative stress parameters were explored in old rats subjected to experimentally induced diabetes and following a long-term treatment with a novel synthetic pyridoindole antioxidant derived from stobadine-SMe1EC2 (2-ethoxycarbonyl-8-methoxy-2,3,4,4a,5,9b-hexahydro-1H-pyrido[4,3-b]indolinium dichloride). Diabetes induced by streptozotocin injection in rats aged 13-15 months, and SMe1EC2 treatment was applied during 4months to aged diabetic rats. AGEs and 4-HNE levels were significantly elevated in brain, ventricle and kidney, but not in lens and liver of aged rats when compared with young rats. Diabetes propagated ageing-induced increase in AGEs and 4-HNE in brain, ventricle and kidney, and raised significantly lens and liver AGEs and 4-HNE levels in aged rats. In aged diabetic rats, SMe1EC2 protected only the kidney against increase in AGEs, and inhibited significantly 4-HNE levels in brain, kidney, liver and lens that were observed more pronounced in lens. 3-NT was significantly increased in brain of aged rats and in kidney, lens and ventricle of aged diabetic rats, while SMe1EC2 has no protective effect on 3-NT increase. Results demonstrate that (1) the responsiveness of different tissue proteins to glyco-lipo-oxidative and nitrosative stress in the course of normal aging was miscellaneous. (2) Diabetes is a major factor contributing to accelerated aging. (3) SMe1EC2 selectively inhibited the generation of oxidatively modified proteins, only in a limited number of tissues.

Therapeutic potential of some plant extracts used in Turkish traditional medicine on streptozocin-induced type 1 diabetes mellitus in rats.

Diabetes mellitus (DM) is known to impair many physiological functions. Some reports claim that medicinal plants can reduce these alterations caused by DM. The aim of this study was to investigate the therapeutic potential of aqueous-methanol extracts of Urtica dioica, Thymus vulgaris (TV), Myrtus communis (MC), Scolymus hispanicus (SH) and Cinnamomun zeylanicum (CZ) on streptozotocin (STZ)-induced type 1 DM in rats. Diabetes was induced via a single i.p. injection of STZ (65 mg/kg body weight). After 1 week to allow for development of diabetes, each plant extract was administered to diabetic rats separately at a dose of 100 mg/kg body weight daily for 28 days. The results showed that only SH extract significantly (P < 0.05) amended fasting blood glucose level. The lipid profile was ameliorated especially by supplementations of TV, MC and CZ extracts. Almost all plant extract treatments markedly (P < 0.05) increased reduced glutathione content and decreased lipid peroxidation levels of erythrocyte, plasma, retina and lens tissues. They also significantly (P < 0.05) amended erythrocyte catalase activity, levels of marker serum enzymes (except amylase), urea and blood urea nitrogen when compared to diabetic rats treated with nothing. Furthermore, none of the plant extracts counteracted body weight loss of diabetic rats. Our data revealed that the aforementioned plant extracts have remarkable potential to counteract DM-caused alterations, probably through their antioxidant and free radical-defusing effects.

Comparative toxicity of 4 commonly used intravitreal corticosteroids on rat retina.

OBJECTIVE: To investigate the effects of 4 commonly used steroids (dexamethasone, triamcinolone, betamethasone, and methylprednisolone) on 50 retinas of 25 adult pigmented rats. STUDY DESIGN: Experimental animal study. PARTICIPANTS: Twenty-five pigmented Long-Evans male rats. METHODS: Each steroid drug with 2 different doses (0.025 mL and 0.050 mL) was injected into the vitreous of each eye of 5 rats. The low drug dose was injected into the right eye and the high dose was injected into the left eye. Ten eyes of 5 randomly selected rats were used as a control group and intravitreal saline was injected into these eyes. Oxidative damage and intrinsic antioxidative capacity were determined by measuring retinal malondialdehyde (MDA) and glutathione (GSH) levels, respectively. RESULTS: No statistically meaningful difference was observed in retinal GSH and MDA measurements in the low- and high-dose triamcinolone (1 and 2 mg), low-dose betamethasone (0.075 mg), and low-dose dexamethasone (0.1 mg) groups, compared with the control group. Both doses of methylprednisolone (1.6 mg and 3.2 mg), high-dose betamethasone (0.15 mg), and high-dose dexamethasone (0.2 mg) markedly altered retinal GSH and MDA levels. CONCLUSIONS: The results of our study show that the toxicity of triamcinolone is not evident even in high doses. It may be used safely. We also suggest that intravitreal use of low doses of betamethasone and dexamethasone is safer than higher doses of these drugs and both doses of methylprednisolone.

Atrial natriuretic peptide inhibits osmotical glial cell swelling in the ischemic rat retina: dependence on glutamatergic-purinergic signaling.

Atrial natriuretic peptide (ANP) is a regulator of the water and electrolyte content in the brain which also mediates cell volume homeostasis. Here, we determined whether the expression of ANP in the retina of the rat undergoes changes during ischemia-reperfusion, and whether ANP affects the osmotic swelling of Müller glial cells in postischemic retinas under hypotonic conditions. Transient retinal ischemia was induced by elevation of the intraocular pressure above systolic blood pressure for 1h. At 1 and 3 days after reperfusion, there was an increased content of ANP protein in the retina, as determined by Western blotting. The increase of the retinal ANP content was markedly reduced when triamcinolone acetonide (10 mM in 2 microl vehicle) was intravitreally injected before ischemia. ANP inhibited the osmotic swelling of Müller cell somata in retinal slices. The effect of ANP was mediated by activation of NP receptors expressed by retinal neurons which evoked a release of glutamate. The stimulation of metabotropic glutamate receptors expressed by Müller cells evoked an autocrine purinergic signaling mechanism that resulted in the opening of K(+) and Cl(-) channels; the ion efflux counteracted the osmotic swelling of Müller cells. It is concluded that the expression of ANP is transiently upregulated in the postischemic retina of the rat. The increased expression of ANP may represent a part of the retinal response to transient ischemia and may inhibit cytotoxic glial cell swelling.

Protective effects of various antioxidants during ischemia-reperfusion in the rat retina.

BACKGROUND: Oxidative stress during ischemia-reperfusion (I/R) is thought to be a major cause of retinal injury after I/R. The present study was aimed at investigating the protective role of antioxidant application. METHODS: Four commonly used antioxidants (vitamin E=alpha tocopherol, lutein, fenugreek=Trigonella foenum-graecum and germander=Teucrium multicaule) were applied in ischemia-reperfusion (I/R) injury of the right retinae of 51 adult pigmented rats. Each of the antioxidants was administered every 6 h, beginning 6 h before the ischemia. After 60 min ischemia and 24 h reperfusion, we assayed (1) oxidative damage by measuring malondialdehyde (MDA), (2) apoptosis by measuring activated caspase-3 (using immunoblots), and (3) intrinsic antioxidative capacity by measuring glutathione (GSH) levels in the retinae. RESULTS: In the order of lutein>Trigonella>vitamin E>Teucrium, all four compounds were effective in preventing retinal damage by I/R, as (1) they significantly decreased the formation of MDA (8.83, 16.48, 17.24, 18.5 nmol/100 mg tissue wet weight, respectively) compared with I/R without protection (23.29 nmol/100 mg tissue wet weight; controls: 8.0 nmol/100 mg tissue wet weight); (2) they significantly inhibited the activation of caspase-3 [0.01, 0.02, 0,02, and 0.04 arbitrary units (AU), respectively, versus control, 0.0, and I/R, 0.08 AU]; and (3) they significantly decelerated the loss of GSH (from control levels of 36.04 nmol/100 mg tissue wet weight) to 30.4, 15.98, 18.1, 15.02 nmol/100 mg tissue wet weight, respectively (lutein, Trigonella, vitamin E, Teucrium), compared with unprotected I/R (12.84 nmol/100 mg tissue wet weight). CONCLUSIONS: Our study shows that lutein, Trigonella, Teucrium and vitamin E exert protection against in vivo retinal I/R injury in rats; this may recommend these compounds (in particular, lutein) for clinical use in patients with different types of ocular I/R injuries.