Calluna vulgaris extract modulates NF-κB/ERK signaling pathway and matrix metalloproteinase expression in SKH-1 hairless mice skin exposed to ultraviolet B irradiation

Photochemoprevention with natural products represents a new concept in the attempt to reduce the occurrence of skin cancer. However, the molecular mechanisms caused by ultraviolet light exposure remain still unclear. The aim of the study was to assess the mechanisms involved in the action of a Calluna vulgaris (Cv) extract, administered in single or multiple doses (10 consecutive days), on UVB-induced skin damage in SKH-1 hairless mice. The extract was topically applied 30 min before each UVB exposure in two doses (2.5 and 4 mg total polyphenolic content/40 μl/cm(2)). At 24 hours after the last treatment, total mitogen-activated protein kinase (p44/42MAPkinase, ERK 1/2), nuclear factor-κB (phospho-NF-κB p65), matrix metalloproteinases (MMP-2, MMP-9) and metalloproteinase inhibitor 1 (TIMP-1) levels were measured in skin using enzyme-linked immunosorbent assay (ELISA). MMP-2 and -9 activities were additionally evaluated by zymography. One topical application of Cv extract reduced the secretion (p<0.004) and inhibited MMP-9 activity UVB-mediated (54% inhibition) via inhibition of NF-κB activation (68% inhibition). In multiple UVB exposures, both doses of Cv extract induced the increase of ERK 1/2 level in correlation with activation of NF-κB and reduced the secretion (p<0.04) and activation of MMP-9 (62% inhibition). Pretreatment with Cv diminished the MMP-2 protein secretion only in one dose UVB-irradiated group (p<0.0001) and decreased TIMP-1 level (p<0.001). These results demonstrated the dual behavior of Cv extract in skin protection against single versus multiple doses of UVB irradiation.

The effects of grape seeds polyphenols on SKH-1 mice skin irradiated with multiple doses of UV-B

The study investigated the protective activity of red grape seeds (Vitis vinifera L, Burgund Mare variety) (BM) extracts in vivo on multiple doses of ultraviolet radiation (UV)-B-induced deleterious effects in SKH-1 mice skin. Eighty 8-weeks-old female SKH-1 mice were divided into 8 groups: control, vehicle, UV-B irradiated, vehicle+UV-B irradiated, BM 2.5mg polyphenols (PF)/cm(2)+UV-B irradiated, BM 4 mg PF/cm(2)+UV-B irradiated, UV-B+BM 2.5mg PF/cm(2), UV-B+BM 4 mg PF/cm(2). The extract was applied topically before or after each UV-B exposure (240 mJ/cm(2)), for 10 days consecutively. The antioxidant activity of BM extract is higher than gallic acid (k(BM)=0.017, k(gallic acid)=0.013). Multiple doses of UV-B generated the formation of cyclobutane pyrimidine dimers (CPDs) and sunburn cells, increased glutathione peroxidase (GPx) and catalase (CAT) activities respectively glutathione (GSH) and IL-1β levels in skin. In group treated with 2.5mg PF/cm(2) before UV-B irradiation BM extract inhibited UV-B-induced sunburn cells, restored the superoxide dismutase (MnSOD) activity, increased insignificantly CAT and GPx activities and reduced IL-1β level. The BM 4.0 mg PF/cm(2) treatment decreased GSH level and reduced the percentage of CPDs positive cells in skin. Both doses of BM extract administered after UV-B irradiation increased the MnSOD and GPx activities and reduced the formation of sunburn cells in skin. Our results suggest that BM extract might be a potential chemo-preventive candidate in reducing the oxidative stress and apoptosis induced by multiple doses of UV-B in skin.

Chemopreventive effects of Calluna vulgaris and Vitis vinifera extracts on UVB-induced skin damage in SKH-1 hairless mice

Solar ultraviolet radiation (UV) is a major cause of non-melanoma skin cancer in humans. Photochemoprevention with natural products represents a simple but very effective strategy in the management of cutaneous neoplasia. The study investigated the protective activity of Calluna vulgaris (Cv) and red grape seeds (Vitis vinifera L, Burgund Mare variety) (BM) extracts in vivo on UVB-induced deleterious effects in SKH-1 mice skin. Forty SKH-1 mice were randomly divided into 4 groups (n=10): control, UVB irradiated, Cv + UVB irradiated, BM+UVB irradiated. Both extracts were applied topically on the skin in a dose of 4 mg/40 μl/cm(2) before UVB exposure - single dose. The effects were evaluated in skin 24 hours after irradiation through the presence of cyclobutane pyrimidine dimers (CPDs) and sunburn cells, tumor necrosis factor-alpha (TNF-α), interleukin (IL)-6 levels. The antioxidant activity of BM extract was higher than those of Cv extract as determined using stable free radical DPPH assay and ABTS test. One single dose of UVB generated formation of CPDs (p<0.0001) and sunburn cells (p<0.0002) and increased the cytokine levels in skin (p<0.0001). Twenty hours following irradiation BM extract inhibited UVB-induced sunburn cells (p<0.02) and CPDs formation (p<0.0001). Pretreatment with Cv and BM extracts resulted in significantly reduced levels of IL-6 and TNF-α compared with UVB alone (p<0.0001). Our results suggest that BM extracts might be a potential candidate in preventing the damages induced by UV in skin.

Comparative study of two evaluation methods for the genotoxic effects of environmental heavy metals on normal cells

Genetic modifications caused by chronic exposure to low levels of toxic metals may activate stress-signaling pathways, thus increasing cancer incidence among affected individuals. The aim of this study was to evaluate the relationship between exposure to heavy metals and the incidence of chromosomal aberrations and DNA lesions in a chronically exposed population by using specific biomarkers. The study included 156 subjects divided into two major groups: exposed individuals (in a heavy metal contaminated region, Maramures, Romania) and non-exposed population, as control group (Cluj, Romania). We compared the results of two cytogenetic methods for the detection and quantification of DNA lesions and chromosomal aberrations in normal human cells: Single Cell Gel Electrophoresis or Comet assay and Cytokinesis Block Micronucleus assay. The methods were performed on lymphocytes isolated from whole blood in density gradient. The basal DNA lesions and chromosomal aberrations were evaluated, as well as the repair capacity of the supplementary lesions induced by genotoxic agents such as ionizing radiations. Our results showed a great interindividual variability in the basal level of the DNA lesions and chromosomal aberrations, between and within the groups, the most affected being the heavy metals-exposed groups. Non-exposed subjects from rural area Cluj appeared to be more susceptible to the induction of supplementary DNA lesions and chromosomal aberrations by irradiation. The most efficient repair capacity of the radio-induced DNA lesions was observed in the non-exposed Cluj urban group. Both cytogenetic assays (as tools for detection of DNA lesions and chromosomal aberrations) may be used in human biomonitoring studies as indicators of early biological effects induced by exposure to heavy metals.

Photochemoprevention of cutaneous neoplasia through natural products

Non-melanoma skin cancers such as squamous cell carcinoma and basal cell carcinoma are the most common types of human tumors, representing 30% of the new cases of malignancies diagnosed each year. Ultraviolet radiation (UV) from the sun is a major cause of non-melanoma skin cancer in humans. The prevention and mainly the photochemoprevention with natural products represent a simple but very effective strategy in the management of cutaneous neoplasia. Here we review the progress in the research of new and existing agents developed to protect the skin exposed to UV. We also discuss the current state of knowledge on their photosuppression mechanism in humans as well as in animal models, and efficiency in cancer prevention.

Effects of 60Co gamma-rays on human osteoprogenitor cells

BACKGROUND

Radiation therapy is one of the most efficient treatments of neoplastic diseases used worldwide. However, patients who undergo radiotherapy may develop side effects that can be life threatening because tissue complications caused by radiation-induced stem cell depletion may result in structural and functional alterations of the surrounding matrix. This treatment also damages the osteogenic activity of human bone marrow by suppressing osteoblasts, leading to post-irradiation sequelae. Even if widely used in oncology, there is still little information on the fate and potential therapeutic efficacy of electromagnetic rays.

MATERIAL AND METHODS

We addressed this question using both human mesenchymal stem cells and osteoblasts. Monoclonal antibody characterization identified specific surface markers for stem cells (SSEA-4, CD29, CD105, Oct 3, Nanog and SOX2) and osteoblasts (Osteopontin and Osteonectin). The technique of anti-alkaline phosphatase FITC-staining demonstrated the presence of this specific ectoenzyme. Cells were cultured in complex osteogenic medium (DMEM, 15% fetal calf serum, non-essential amino acids, L-glutamine, dexametazone, ascorbic acid, insulin, TGF-beta, BMP-2 and beta-glycero-phosphate) after being irradiated at 0.5 Gy, 1 Gy, 2 Gy and 4 Gy using a Theratron 1000 60Co source. The viability of irradiated cells was assessed using Trypan Blue staining. The comparison between cell lineages after culture in osteogenic media regarding phenotypical characterization and the intensity of the mineralization process included histology stainings (Alizarin Red S, Alcian Blue and von Kossa), and the MTT-based proliferation assay.

RESULTS

After irradiation, the proliferation and differentiation of osteoprogenitor cells is dose-dependent.

CONCLUSIONS

This study is one among the first papers investigating the biophysics of low-dose gamma-irradiation on stem cell culture, focusing on the potential applications in radiation oncology and various palliative treatments.

Inhibitory effect of some esters of 4-hydroxy-5-nitro-4,5-dihydrothymine on the growth of tumor cells

New analogs of 4-hydroxy-5-nitro-4,5-dihydrothymine, namely 4-acyloxy-5-nitro-4,5-dihydrothymines (where: acyl = acetyl, benzoyl, mono- and dichloroacetyl) were synthesized and tested for their toxicologic and antitumor effects on Ehrlich ascites tumor cells and Ehrlich solid tumor. Best results were found for the mono- and dichloroacetyl derivatives.

Characterization of metronidazole-phosphate, a water-soluble metronidazole derivative, as a radiosensitizer of hypoxic cells

A water-soluble derivative of metronidazole (Flagyl) was synthetized with the purpose to overcome some practical difficulties in the clinical administration of the drug. The derivative, a phosphate ester of metronidazole, was characterized for different physical-chemical properties. It had a low toxicity both in vitro and in vivo. In vitro, it retained a radiosensitizing effect specific for hypoxic cells which was, however, decreased in comparison with the parent compound. The decreased sensitization was related to a decreased one-electron reduction potential and octanol/water partition coefficient. In mice, metronidazole-phosphate had a prolonged blood life in comparison to metronidazole.