Protective roles of Gadd45 and MDM2 in blueberry anthocyanins mediated DNA repair of fragmented and non-fragmented DNA damage in UV-irradiated HepG2 cells

Proton irradiation induced reactive oxygen species promote morphological and functional changes in HepG2 cells

The increased use of proton therapy has led to the need of better understanding the cellular mechanisms involved. The aim of this study was to investigate the effects induced by the accelerated proton beam in hepatocarcinoma cells. An existing facility in IFIN-HH, a 3 MV Tandetron™ accelerator, was used to irradiate HepG2 human hepatocarcinoma cells with doses between 0 and 3 Gy. Colony formation was used to assess the influence of radiation on cell long-term replication. Also, the changes induced at the mitochondrial level were shown by increased ROS and ATP levels as well as a decrease in the mitochondrial membrane potential. An increased dose has induced DNA damages and G₂/M cell cycle arrest which leads to caspase 3/7 mediated apoptosis and senescence induction. Finally, the morphological and ultrastructural changes were observed at the membrane level and the nucleus of the irradiated cells. Thus, proton irradiation induces both morphological and functional changes in HepG2 cells.

The Effects of Blueberry Phytochemicals on Cell Models of Inflammation and Oxidative Stress

Blueberries have been extensively studied for the health benefits associated with their high phenolic content. The positive impact of blueberry consumption on human health is associated in part with modulation of proinflammatory molecular pathways and oxidative stress. Here, we review in vitro studies examining the anti-inflammatory and antioxidant effects of blueberry phytochemicals, discuss the results in terms of relevance to disease and health, and consider how different blueberry components modulate cellular mechanisms. The dampening effects of blueberry-derived molecules on inflammation and oxidative stress in cell models have been demonstrated through downregulation of the NF-κB pathway and reduction of reactive oxygen species (ROS) and lipid peroxidation. The modulatory effects of blueberry phytochemicals on the mitogen-activated protein kinase (MAPK) pathway and antioxidant system are not as well described, with inconsistent observations reported on immune cells and between models of endothelial, dermal, and ocular inflammation. Although anthocyanins are often reported as being the main bioactive compound in blueberries, no individual phytochemical has emerged as the primary compound when different fractions are compared; rather, an effect of whole blueberry extracts or synergy between different phenolic and nonphenolic extracts seems apparent. The major molecular mechanisms of blueberry phytochemicals are increasingly defined in cell models, but their relevance in more complex human systems needs further investigation using well-controlled clinical trials, in which systemic exposures to blueberry-associated molecules are measured concurrently with physiologic indices of inflammation and oxidative stress.

9-phenyl acridine photosensitizes A375 cells to UVA radiation

Acridines are an important class of bioactive molecules having varied uses. Its derivative, 9-phenylacridine (ACPH) had been found to exhibit antitumor activity both in cell lines and in vivo model. Its DNA binding ability and absorbance in the ultraviolet range encouraged us to investigate its role as a photosensitizer with UVA radiation. We investigated the effects of ACPH prior to UVA exposure on in vitro DNA through photo-cleavage assay. Effect of such treatment was also studied in cultured A375 melanoma cells. Endpoints studied included morphological changes, evaluation of cellular viability, scratch assay, intracellular reactive oxygen species (ROS) production, DNA damage, lipid peroxidation, glutathione (GSH) level, autophagy, cell cycle progression, depletion of mitochondrial membrane potential (ΔΨmt), induction of apoptosis and Hoechst dye efflux assay. Our findings indicated that ACPH could sensitize damage to DNA induced by UVA both in vitro and in cells. It could also potentiate cell killing by UVA. It arrested cells in G2/M phase and induced apoptotic death through mitochondria mediated pathway. This sensitization was through enhancement of intracellular ROS. Our findings also indicated that the stem cells side population was reduced on such treatment. The findings are important as it indicates ACPH as a promising photosensitizer and indicates its possible role in photodynamic therapy.

Attenuation of hydrogenperoxide-induced oxidative damages in L929 fibroblast cells by sulfated polysaccharides isolated from the edible marine algae Padina tetrastromatica

Sulfated polysaccharides are polymers with potent biological roles such as antioxidant, anticancer, anti-inflammatory, and immunomodulatory activities. They are gaining significance in advanced healthcare research, since they can control oxidative cellular damages by arresting the reactive oxygen species. Hence, this study aims to evaluate the cellular antioxidant potential of sulfated polysaccharides isolated from the marine algae Padina tetrastromatica in L929 cells. The monosaccharide composition of sulfated polysaccharides was determined using high-performance liquid chromatography. The protective effect of sulfated polysaccharides on L929 fibroblast cells under H2O2-induced oxidative stress has been evaluated using MTT assay, acridine orange/ethidium bromide staining, flow cytometry, comet assay, DCFH-DA staining, fluorometry, and biochemical assays. Sulfated polysaccharides were found to contain glucose, fucose, xylose, and uronic acid. It was non-toxic to L929 cells and effectively increased the viability of mouse fibroblast cells under induced oxidative stress. Various cellular damages such as apoptosis, plasma membrane alterations, DNA damage, and lipid peroxidation induced by H2O2 have been attenuated by sulfated polysaccharides. This might be due to the reduction of intracellular reactive oxygen species level by sulfated polysaccharides as observed in DCFH-DA staining. Sulfated polysaccharides improved the activity of intracellular antioxidant status and glutathione system. The augmentation of endogenous antioxidant enzymes and glutathione system by sulfated polysaccharides can be the possible reason for the reduction of intracellular reactive oxygen species, prevention of apoptosis, and betterment of viability in L929 cells. The study confirms the potent antioxidant activity of the sulfated polysaccharides in addition to their structural and nutritional roles.

Boysenberry polyphenol inhibits endothelial dysfunction and improves vascular health

Endothelial cells have an important role in maintaining vascular homeostasis. Age-related disorders (including obesity, diabetes, and hypertension) or aging per se induce endothelial dysfunction that predisposes to the development of atherosclerosis. Polyphenols have been reported to suppress age-related endothelial cell disorders, but their role in vascular function is yet to be determined. We investigated the influence of boysenberry polyphenol on vascular health under metabolic stress in a murine model of dietary obesity. We found that administration of boysenberry polyphenol suppressed production of reactive oxygen species (ROS) and increased production of nitric oxide (NO) in the aorta. It has been reported that p53 induces cellular senescence and has a crucial role in age-related disorders, including heart failure and diabetes. Administration of boysenberry polyphenol significantly reduced the endothelial p53 level in the aorta and ameliorated endothelial cell dysfunction in iliac arteries under metabolic stress. Boysenberry polyphenol also reduced ROS and p53 levels in cultured human umbilical vein endothelial cells (HUVECs), while increasing NO production. Uncoupled endothelial nitric oxide synthase (eNOS monomer) is known to promote ROS production. We found that boysenberry polyphenol reduced eNOS monomer levels both in vivo and in vitro, along with an increase of eNOS dimerization. To investigate the components of boysenberry polyphenol mediating these favorable biological effects, we extracted the anthocyanin fractions. We found that anthocyanins contributed to suppression of ROS and p53, in association with increased NO production and eNOS dimerization. In an ex vivo study, anthocyanins promoted relaxation of iliac arteries from mice with dietary obesity. These findings indicate that boysenberry polyphenol and anthocyanins, a major component of this polyphenol, inhibit endothelial dysfunction and contribute to maintenance of vascular homeostasis.

Down-regulation of GADD45A enhances chemosensitivity in melanoma

Melanoma is a malignant skin cancer with considerable drug resistance. Increased expression of DNA repair genes have been reported in melanoma, and this contributes to chemotherapy resistance. GADD45A is involved in DNA repair, cell cycle arrest and apoptosis in response to physiologic or environmental stresses. In this study, we investigated the role of GADD45A in chemotherapy response. Firstly, the mRNA expression of profiled DNA repair genes in cisplatin-treated melanoma cells was detected by RT2 profilerTM PCR array. We found the expression of GADD45A upregulated in a dose- and time- dependent manner. In addition, suppression of GADD45A sensitized melanoma cells to cisplatin and enhanced cisplatin-induced DNA damage. Flow cytometry revealed that downregulating GADD45A released cells from cisplatin-induced G2/M arrest and increased apoptosis. By using a MEK inhibitor, GADD45A was shown to be regulated by MAPK-ERK pathway following cisplatin treatment. Thus, the induction of GADD45A might play important roles in chemotherapy response in human melanoma cancer and could serve as a novel molecular target for melanoma therapy.

Effects of microRNA-374 on proliferation, migration, invasion, and apoptosis of human SCC cells by targeting Gadd45a through P53 signaling pathway

The present study investigated the effects of microRNA-374 (miR-374) on human squamous cell carcinoma (SCC) cell proliferation, migration, invasion, and apoptosis through P53 signaling pathway by targeting growth arrest and DNA-damage-inducible protein 45 α (Gadd45a). Skin samples were collected from patients with skin SCC and normal skin samples. Expression of miR-374, Gadd45a, P53, P73, P16, c-myc, bcl-2, Bax, caspase-3, and caspase-9 were detected using quantitative real-time polymerase chain reaction (qRT-PCR) and Western blotting. A431 and SCL-1 cells were divided into blank, negative control (NC), miR-374 mimics, miR374 inhibitors, siRNA–Gadd45a, and miR-374 inhibitors + siRNA–Gadd45a groups. Their proliferation, migration, invasion, cell cycle, and apoptosis were evaluated by 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide (MTT) assay, scratch test, Transwell assay, and flow cytometry. SCC skin tissues exhibited decreased expression of miR-374, P73, P16, Bax caspase-3 and caspase-9, and increased levels of Gadd45a, P53, c-myc, and Bcl-2 compared with the normal skin tissues. The miR-374 inhibitors group exhibited decreased expression of miR-374, P73, P16, Bax caspase-3 and caspase-9, and increased expression of Gadd45a, P53, c-myc, and Bcl-2, enhanced cell proliferation, migration, and invasion, and reduced apoptosis compared with the blank and NC groups; the miR-374 mimics group followed opposite trends. Compared with the blank and NC groups, the miR-374 inhibitors + siRNA–Gadd45a group showed decreased miR-374 level; the siRNA–Gadd45a group showed elevated levels of P73, P16, Bax, caspase-3 and caspase-9, decreased levels of Gadd45a, P53, c-myc, and Bcl-2, reduced cell proliferation, migration, and invasion, and accelerated apoptosis. miR-374 induces apoptosis and inhibits proliferation, migration, and invasion of SCC cells through P53 signaling pathway by down-regulating Gadd45a.

Differential iridoid production as revealed by a diversity panel of 84 cultivated and wild blueberry species

Cultivated blueberry (Vaccinium corymbosum, Vaccinium angustifolium, Vaccinium darrowii, and Vaccinium virgatum) is an economically important fruit crop native to North America and a member of the Ericaceae family. Several species in the Ericaceae family including cranberry, lignonberry, bilberry, and neotropical blueberry species have been shown to produce iridoids, a class of pharmacologically important compounds present in over 15 plant families demonstrated to have a wide range of biological activities in humans including anti-cancer, anti-bacterial, and anti-inflammatory. While the antioxidant capacity of cultivated blueberry has been well studied, surveys of iridoid production in blueberry have been restricted to fruit of a very limited number of accessions of V. corymbosum, V. angustifolium and V. virgatum; none of these analyses have detected iridoids. To provide a broader survey of iridoid biosynthesis in cultivated blueberry, we constructed a panel of 84 accessions representing a wide range of cultivated market classes, as well as wild blueberry species, and surveyed these for the presence of iridoids. We identified the iridoid glycoside monotropein in fruits and leaves of all 13 wild Vaccinium species, yet only five of the 71 cultivars. Monotropein positive cultivars all had recent introgressions from wild species, suggesting that iridoid production can be targeted through breeding efforts that incorporate wild germplasm. A series of diverse developmental tissues was also surveyed in the diversity panel, demonstrating a wide range in iridoid content across tissues. Taken together, this data provides the foundation to dissect the molecular and genetic basis of iridoid production in blueberry.

Anthocyanins from roselle extract arrest cell cycle G2/M phase transition via ATM/Chk pathway in p53-deficient leukemia HL-60 cells

Cell cycle regulation is an important issue in cancer therapy. Delphinidin and cyanidin are two major anthocyanins of the roselle plant (Hibiscus sabdariffa). In the present study, we investigated the effect of Hibiscus anthocyanins (HAs) on cell cycle arrest in human leukemia cell line HL-60 and the analyzed the underlying molecular mechanisms. HAs extracted from roselle calyces (purity 90%) markedly induced G2/M arrest evaluated with flow cytometry analysis. Western blot analyses revealed that HAs (0.1-0.7 mg mL^-1 ) induced G2/M arrest via increasing Tyr15 phosphorylation of Cdc2, and inducing Cdk inhibitors p27 and p21. HAs also induced phosphorylation of upstream signals related to G2/M arrest such as phosphorylation of Cdc25C tyrosine phosphatase at Ser216, increasing the binding of pCdc25C with 14-3-3 protein. HAs-induced phosphorylation of Cdc25C could be activated by ATM checkpoint kinases, Chk1, and Chk2. We first time confirmed that ATM-Chk1/2-Cdc25C pathway as a critical mechanism for G2/M arrest in HAs-induced leukemia cell cycle arrest, indicating that this compound could be a promising anticancer candidate or chemopreventive agents for further investigation. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 1290-1304, 2017.

Inhibition of pancreatic cancer cell migration by plasma anthocyanins isolated from healthy volunteers receiving an anthocyanin-rich berry juice

PURPOSE

Pancreatic cancer is an aggressive cancer type, of which the most important characteristics are migration and metastasis. Anthocyanins (ACN) are discussed to be protective phytochemicals; however, up to now only scarce data are available regarding their effects on cancer prevention. In this study, we aimed to determine whether ACN and their metabolites from plasma (PAM), isolated from blood of healthy volunteers after ingestion of an ACN-rich juice, are effective in modulating cancer cell migration in vitro.

METHODS

PAM were isolated from blood of healthy volunteers (n = 10) after consumption of an ACN-rich berry juice. Before ingestion (PAM_0min) and after 60 min (PAM_60min), blood was taken and PAM were isolated from plasma by solid-phase extraction. Migration of pancreatic cancer cells PANC-1 and AsPC-1 was assayed in a Boyden chamber. The influence of PAM on cellular reactive oxygen species (ROS) or mitochondria-specific ROS was measured fluorimetrically. mRNA expression levels of matrix metalloproteinases (MMP-2 and MMP-9) and NF-κB mRNA were determined by real-time PCR.

RESULTS

After application of PAM_60min to PANC-1, we observed a reduced cell migration, which was associated with reduced levels of endogenously generated ROS concomitant with reduced NF-κB as well as MMP-2 and MMP-9 mRNA expression levels. In AsPC-1 cells, however, migration was not affected by PAM_60min.

CONCLUSION

It can be assumed that physiologically relevant ACN and their metabolites were able to inhibit pancreatic cancer cell migration in dependency of the phenotype of cells and may thus deserve further attention as potential bioactive phytochemicals in cancer prevention.

Blueberry Anthocyanins-Enriched Extracts Attenuate Cyclophosphamide-Induced Cardiac Injury

We sought to explore the effect of blueberry anthocyanins-enriched extracts (BAE) on cyclophosphamide (CTX)-induced cardiac injury. The rats were divided randomly into five groups including normal control, CTX 100 mg/kg, BAE 80mg/kg, CTX+BAE 20mg/kg and CTX+BAE 80mg/kg groups. The rats in the three BAE-treated groups were administered BAE for four weeks. Seven days after BAE administration, rats in CTX group and two BAE-treated groups were intraperitoneally injected with a single dose of 100 mg/kg CTX. Cardiac injury was assessed using physiological parameters, Echo, morphological staining, real-time PCR and western blot. In addition, cardiotoxicity indices, inflammatory cytokines expression and oxidative stress markers were also detected. Four weeks 20mg/kg and 80mg/kg dose of BAE treatment following CTX exposure attenuated mean arterial blood pressure, heart rate and activities of heart enzymes, improved cardiac dysfunction, left ventricular hypertrophy and fibrosis. Importantly, BAE also attenuated CTX-induced LV leukocyte infiltration and inflammatory cytokines expression, ameliorated oxidative stress as well as cardiomyocyte apoptosis. In conclusion, BAE attenuated the CTX-induced cardiac injury and the protective mechanisms were related closely to the anti-inflammatory, antioxidant and anti-inflammatory characteristics of BAE.

Role of p53β in the inhibition of proliferation of gastric cancer cells expressing wild-type or mutated p53

p53 is a tumor suppressor gene whose mutation is highly associated with tumorigenesis. The present study investigated the role of p53β in the inhibition of proliferation of gastric cancer cell lines expressing wild-type or mutated p53. Wild-type p53 is expressed in MKN45 cells, but deleted in KATOIII cells, whereas mutated p53 is expressed in SGC7901 cells. The mRNA expression levels of p53β and Δ133p53 were detected in MKN45, SGC-7901 and KATOIII gastric cancer cell lines using nested polymerase chain reaction (PCR). The mRNA expression levels of p53, p53β and B-cell lymphoma 2-associated X protein (Bax) were detected in the MKN45 and SGC-7901 cells following treatment with cisplatin by reverse transcription-PCR. The inhibition of cellular proliferation following treatment with cisplatin was measured by MTT assay. The results of the present study demonstrated that both p53β and Δ133p53 mRNA were expressed in the MKN45 cells, whereas only p53β mRNA was expressed in the SGC7901 cells. No expression of p53β or Δ133p53 mRNA was detected in the KATOIII cells. Following treatment with cisplatin, the number of both MKN45 and SGC-7901 cells was significantly reduced (P<0.001). In the MKN45 cells, p53β, p53 and Bax mRNA expression levels gradually increased with the dose of cisplatin, and the expression of p53β was positively correlated with the expression of p53 (tr=6.358, P<0.05) and Bax (tr=8.023, P<0.05). In the SGC-7901 cells, the expression levels of p53β, p53 and Bax mRNA did not alter with the dose of cisplatin, and the expression of p53β was positively correlated to the expression of p53 (tr=26.41, P<0.01) but not that of Bax. The present study identified the different roles of the p53β isoform in gastric cancer cells with different p53 backgrounds. Enhanced knowledge regarding the p53 status is required for the development of specific biological therapies against gastric cancer.

Antiproliferative and antioxidant properties of anthocyanin rich extracts from blueberry and blackcurrant juice

The present study was aimed at evaluating the antiproliferative potential of anthocyanin-rich fractions (ARFs) obtained from two commercially available juices (blueberry and blackcurrant juices) on three tumor cell lines; B16F10 (murine melanoma), A2780 (ovarian cancer) and HeLa (cervical cancer). Individual anthocyanin determination, identification and quantification were done using HPLC-MS. Antioxidant activity of the juices was determined through different mechanism methods such as DPPH and ORAC. For biological testing, the juices were purified through C18 cartridges in order to obtain fractions rich in anthocyanins. The major anthocyanins identified were glycosylated cyanidin derivatives. The antiproliferative activity of the fractions was tested using the MTT assay. The antiproliferative potential of ARF was found to be associated with those bioactive molecules, anthocyanins due to their antioxidant potential. The results obtained indicated that both blueberry and blackcurrants are rich sources of antioxidants including anthocyanins and therefore these fruits are highly recommended for daily consumption to prevent numerous degenerative diseases.