The detection of curcumins' antitumoral effects via argyrophilic nucleolar organizing region-associated protein synthesis in mice with ehrlich's ascitic carcinoma.

BACKGROUND: Curcumin is a polyphenol compound that has antioxidant, anticancer, anti-inflammatory, anti-hyperlipidemic and antimicrobial effects. Nucleolar-organizing regions are the sites of the gene on chromosomes. The present study was aimed to show the antitumoral effect of curcumin via AgNOR protein synthesis in Ehrlich's ascitic carcinoma (EAC) bearing mice. METHODS: Twenty three mice with EAC were randomly divided into 3 groups as positive control (n = 7), group 2 (n = 8) and 3 (n = 8) treated intraperitoneally with curcumin (25 mg/kg) and (50 mg/kg), respectively. The animals were sacrificed on Day 16, the solid tumors were removed out. Then, total AgNOR area/nuclear area (TAA/NA) and the mean AgNOR number were estimated for each mice. RESULT: Statistically significant differences were determined among the whole groups for TAA/NA ratio (p = 0.000), conversely mean AgNOR number (p = 0.361). When comparingthe two groups; while no difference was determined between the control and curcumin (25 mg/kg) groups (p = 0.061), the significant differences were detected between the control and curcumin (50 mg/kg) groups (p = 0.000) and between curcumin (25 mg/kg) and curcumin (50 mg/kg) groups (p = 0.000) for TAA/NA ratio. However, there was no significant difference for the mean AgNOR number in double comparison of the groups. CONCLUSIONS: The current study showed that curcumin had a crucial function against cancer development. Also, both AgNOR values might be used as biomarkers for detection of the most reliable therapeutic dose selection of cancer treatment (Tab. 3, Fig. 2, Ref. 27).

May argyrophilic nucleolar organizing region-associated protein synthesis be used for selecting the most reliable dose of drugs such as rhamnetin in cancer treatments?

BACKGROUND: Rhamnetin is a flavonoid that has antioxidant, anti-inflammatory and anti-cancer effects. Nucleolar-organizing regions are the ribosomal genes region. We aimed to identify whether rhamnetin has an effect on cell proliferation and whether AgNOR proteins may be used for the detection of therapeutic benefits of the drugs and new metabolites, which have the potential of being used for cancer treatments. METHODS: Twenty-four mice with Ehrlich's ascites carcinoma (EAC) were randomly assigned to three main groups as positive control, and groups 2 and 3 treated intraperitoneally with rhamnetin (100 µg/kg and 200 µg/kg, respectively). All the animals were sacrificed on day16, 24 h after the last dose; the tumors, which developed at the site of injection were removed. Then, mean AgNOR number and total AgNOR area/nuclear area (TAA/NA) were detected for each mouse. RESULTS: Significant differences were detected among all groups for mean AgNOR number (p = 0.000) and TAA/NA ratio (p = 0.000). While the difference between positive control and Rhamnetin (100 µg/kg) group was not significant (p = 0.387), there are significant differences between positive control and Rhamnetin (200 µg/kg) group (p = 0.000) and between Rhamnetin (100 µg/kg) and Rhamnetin (200 µg/kg) groups (p = 0.000) for TAA/NA ratio. CONCLUSION: Rhamnetin has an important role in preventing cancer formation. Our study showed that mean AgNOR numbers and TAA/NA values may be used also as biomarkers for evaluating the success rate of the performed therapeutic strategy and accurate dose selection for the management of the disease (Tab. 3, Fig. 3, Ref. 45).

O impacto na expressão agnors e apoptose na próstata do hamster-mesocricetus auratus (HMA) submetido à aplicação de finasterida / The impact in the agnors expression and apoptosis in the prostate of hamster-mesocricetus auratus (HMA) submitted to finasteride application

OBJETIVO: Avaliar o impacto na expressão AgNORs e apoptose na próstata do hamster-Mesocricetus auratus (hMa) submetido à aplicação de finasterida. MÉTODOS: Vinte roedores da espécie hMa (n=20), machos foram separados aleatoriamente em grupos de dez animais: grupo-Finasterida (n=10) e grupo-Controle (n=10). No grupo-finasterida foi administrado 7,14 ng/mL de finasterida, subcutâneo (SC), no dorso, três vezes por semana, por 90 dias. Foi avaliada a expressão AgNORs como marcador de proliferação celular e a apoptose como marcador de morte celular. RESULTADOS: A expressão de AgNORs foi menor no grupo-finasterida, 2,846±0,877 versus 3,68 ±1,07 grumos argilófilos por micrômetro ao quadrado (µm²) no grupo-controle, p= < 0,0001. A apoptose foi mais frequente no grupo-finasterida, 53,62±1,389 versus 14,76 ± 2,137 µm² no grupo-controle, p= 0,0408. CONCLUSÃO: Observou-se diminuição da expressão de AgNORs e promoção da apoptose na próstata dos roedores em estudo, que foram submetidos à aplicação de finasterida.

OBJECTIVE: To evaluate the impact on the AgNORs expression and apoptosis in the prostate of the hamster-Mesocricetus auratus (HMA) submitted to the application of finasteride. METHODS: Twenty male rodents of the species HMA (n = 20) were randomly assigned to groups of ten animals: Finasteride group (n = 10) and the Control group (n = 10). In the finasteride group 7.14 ng / mL finasteride was subcutaneously (SC) administered on the back of the animals three times a week for 90 days. AgNOR expression was evaluated as a marker of cell proliferation and apoptosis as a marker of cell death. RESULTS: The expression of AgNORs was lower in the finasteride group, 2.846 ± 0.877 vs. 3.68 ± 1.07 argyrophilic regions per square micrometer (µm2) in the control group, p = <0.0001. Apoptosis was more frequent in the finasteride group, 53.62 ± 1.389 versus 14.76 ± 2.13 per µm2 in the control group, p = 0.0408. CONCLUSION: We observed decreased expression of AgNORs and promotion of apoptosis in the prostate of rodents treated with finasteride.

Morphological factors as indicators of malignancy of squamous cell carcinomas in cattle exposed naturally to bracken fern (Pteridium aquilinum).

Squamous cell carcinomas (SCCs) of the upper digestive tract (UDT) of cattle have been associated with chronic bracken fern (Pteridium aquilinum) toxicity and infection with bovine papillomavirus type-4. These tumours share some morphological similarities with human head and neck SCCs. In this study, morphological changes were correlated with the biological behaviour of 40 alimentary SCCs in cattle grazing on pastures with high bracken content. The majority of SCCs were localized to the cranial and caudal regions of the UDT (almost 45% each). More than 60% of the tumours were well differentiated and were found mostly in the cranial region. Metastasis occurred in 58% of the cases, mostly to regional lymph nodes. All poorly differentiated SCCs had evidence of metastasis. Morphological patterns characterized by islands and ribbons of neoplastic keratinocytes were more prominent in well differentiated SCCs. These patterns varied greatly in moderately differentiated SCCs. Poorly differentiated tumours were characterized by the presence of cellular aggregates and individual cells and these tumours had more marked desmoplasia. A significant positive association was established between lymphoplasmacytic inflammatory infiltration and tumour-associated tissue eosinophilia. Evaluation of argyrophylic nucleolar organizer regions (AgNORs) revealed higher proliferation indices in poorly differentiated tumours than in moderately or well differentiated lesions. There was significant correlation between the AgNOR index and histological grading. The morphological factors analyzed were all related to histological grading, which is the major factor predicting the biological behaviour of SCCs in cattle naturally exposed to bracken fern.

Effect of indoor air pollution from biomass fuel use on argyrophilic nuclear organizer regions in buccal epithelial cells.

This study investigated the effect of indoor air pollution from biomass-fuel use on the expression of argyrophilic nucleolar organizer regions (AgNORs), an indicator of ribosome biosynthesis, in epithelial cells of oral mucosa. AgNORs were evaluated using cytochemical staining in 62 nonsmoking indian women (median age, 34 years), who cooked exclusively with biomass, and 55 age-matched women, who were from a similar neighborhood and cooked with relatively clean liquefied petroleum gas (LPG). Concentrations of particulate pollutants in indoor air were measured using a real-time aerosol monitor. Compared to the LPG-using controls, biomass-fuel users showed a remarkably increased number of AgNOR dots per nucleus (6.08 +/-2.26 vs 3.16 +/-0.86, p < 0.001), AgNOR size (0.85 +/-0.19 vs 0.53 +/-0.15 mum2, p < 0.001), and percentage of AgNOR-occupied nuclear area (4.88 +/-1.49 vs 1.75 +/-0.13%, p < 0.001). Biomass-using households had 2 to 4 times more particulate pollutants than that of LPG-using households. The changes in AgNOR expression were positively associated with PM10 and PM2.5 levels in indoor air after controlling for potential confounders such as age, kitchen location, and family income. Thus, biomass smoke appears to be a risk factor for abnormal cell growth via upregulation of ribosome biogenesis.

Activities of DNA-PK and Ku86, but not Ku70, may predict sensitivity to cisplatin in human gliomas.

OBJECTIVE: This study was designed to investigate the relationship between activities of DNA-dependent protein kinase (DNA-PK), its subunits Ku86/Ku70, and sensitivities to cisplatin in human glioma samples. METHODS: Thirty-six glioma samples from patients without prior treatment before neurosurgery were included in this study. The sensitivities to cisplatin as indicated by IC(50) (the inhibitory concentration leading to 50% cell death) were assessed by 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenytetrazolium (MTT) assay; activities of DNA-PK and Ku70/Ku86 were analyzed by SigmaTECT DNA-Dependent Protein Kinase Assay System and Ku70/Ku86 DNA Repair Kit, respectively. RESULTS: Sensitivities to cisplatin correlated with the activities of DNA-PK/Ku86, but not with the Ku70 or other clinical parameters such as age, sex of the patients, pathological gradings of the tumors, or tumor size. The levels of DNA-PK activities also associated with pathological grading and Ku86, but not with other clinical parameters. The tumors of the patients who failed to respond to cisplatin-based chemotherapy tended to display higher activity levels of DNA-PK and Ku86. Furthermore, platinum-based chemotherapy did not result in significant changes of DNA-PK/Ku activities in four matched samples before and after chemotherapy. CONCLUSION: Pretreatment determination of DNA-PK/Ku86 activities might be helpful in identifying patients who will actually benefit from platinum-based treatment.

Aberrant crypt foci and AgNORs as putative biomarkers to evaluate the chemopreventive efficacy of pronyl-lysine in rat colon carcinogenesis.

Chemoprevention opens new perspectives in the prevention of cancer and other degenerative diseases. Use of target-organ biological models at the histological and genetic levels can markedly facilitate the identification of potential chemopreventive agents. Our aim was to study the chemopreventive efficacy of pronyl-lysine, a key antioxidant present in bread crust by evaluating, the total number of aberrant crypt foci (ACF), their distributions, dysplastic ACF, colonic tumor incidence and the expression of cell proliferation biomarker such as the argyrophilic nucleolar organizing region-associated proteins (AgNORs) in 1,2-dimethylhydrazine (DMH) induced colon cancer in rats. Male Wistar rats were randomized into seven groups, group 1 were control rats, group 2 received pronyl-lysine (2 mg/kg body weight p.o. everyday), rats in groups 3-7 were administered DMH (20 mg/kg body weight) in the groin for 15 weeks. In addition, group 4 (pre-initiation), 5 (initiation), 6 (post-initiation), and 7 (entire period) received pronyl-lysine (2 mg/kg body weight p.o) everyday. At the end of 34 weeks, pronyl-lysine supplementation showed markedly reduced tumor incidence, ACF development and also lowered number of AgNORs. Overall, these findings confirm that pronyl-lysine has a positive beneficial effect against chemically induced colonic preneoplastic progression in rats.

Nuclear loss of DNA repair Ku proteins and c-myc expression in apoptosis of cerulein-stimulated pancreatic acinar cells.

Cerulein induces oxidative stress and an acute, edematous form of pancreatitis. Cell death linked to oxidative DNA damage has been implicated in acute pancreatitis. During DNA damage, DNA repair proteins, Ku70 and Ku80, prevent cell death but severe DNA damage triggers apoptosis. This study aims to investigate the role of Ku70 and Ku80 on apoptotic cell death, induced by cerulein in pancreatic acinar AR42J cells. We examined Ku expression, Ku-DNA binding activity, cell viability and mRNA expression of c-myc of the cells stimulated with cerulein. As a result, cerulein induced decrease in nuclear Ku70 and Ku80 with increase in cytoplasmic Ku proteins. Cerulein decreased Ku-DNA binding activity in parallel with increase in cell death and mRNA expression of c-myc. Conclusively, nuclear loss of Ku70 and Ku80 may cause the loss of defense against DNA damage and apoptosis in pancreatic acinar cells stimulated with cerulein.

Vorinostat, a histone deacetylase inhibitor, enhances the response of human tumor cells to ionizing radiation through prolongation of gamma-H2AX foci.

Vorinostat (suberoylanilide hydroxamic acid) is the prototype of a family of hybrid polar compounds that can induce growth arrest in transformed cells and shows promise for the treatment of cancer. Vorinostat specifically binds to and inhibits the activity of histone deacetylases resulting in acetylation of nucleosomal histones and an activation of gene transcription. Because histone deacetylases modulate chromatin structure and gene expression, both of which can influence radioresponse, this study was designed to examine the capacity of Vorinostat to influence radiation response in human tumor cells and investigate the mechanism underlying these interactions. Vorinostat induced hyperacetylation of histone H4 in a dose-dependent manner. We tested its ability to radiosensitize three human tumor cell lines (A375, MeWo, and A549) using clonogenic cell survival assays. Clonogenic cell survival assay showed that Vorinostat significantly radiosensitized all three tumor cell lines, substantially reducing the surviving fraction at 2 Gy. We examined potential mechanisms that may contribute to the enhanced radiation response induced by Vorinostat. Vorinostat and radiation alone did not induce apoptosis in the melanoma cell line. However, enhanced apoptosis was observed when cells were exposed to both Vorinostat and radiation, suggesting that Vorinostat renders tumor cells more susceptible to radiation-induced apoptosis. Results from DNA damage repair analysis in cultured A375 cells showed that Vorinostat had a strong inhibitory effect on the nonhomologous end joining pathway after radiation. A detailed examination of the involvement of the DNA repair pathway following Vorinostat treatment showed that Vorinostat reduced the expression of the repair-related genes Ku70, Ku80, and Rad50 in A375 cells as detected by Western blot analysis. We also examined gamma-H2AX phosphorylation as a predictive marker of radiotherapy response to Vorinostat and observed that the combination of Vorinostat and radiation caused a prolongation of expression of DNA repair proteins such as gamma-H2AX. Overall, we conclude that Vorinostat enhances tumor radioresponse by multiple mechanisms that may involve antiproliferative growth inhibition and effects on DNA repair after exposure to radiation.

The expression and the nuclear activity of the caretaker gene ku86 are modulated by somatostatin.

Somatostatin is a peptide hormone that exerts antisecretory and antiproliferative activities on some human tumors. The Ku70/86 heterodimer acts as regulatory subunit of the DNA dependent protein kinase and its DNA binding activity mediates DNA double strands breaks repair that is crucial to maintain the genetic integrity of the genome. The activation of the heterodimer regulates cell cycle progression and the activity of nuclear transcription factors involved in DNA replication and cell proliferation. Moreover Ku86 behaves as a receptor for the growth inhibitory tetradecapeptide, somatostatin. Herein we report that somatostatin treatment to a colon carcinoma cell line (Caco-2) inhibits cell growth and, at same time, strongly modulates the activation of Ku70/86 heterodimer and the levels of Ku86 in the nucleus by increasing its specific mRNA level. Our findings are consistent with the hypothesis that somatostatin controls cell cycle progression and DNA repair through a new signalling pathway that involves the regulation of Ku86 level and modulates the Ku70/86 activity in the nucleus.