Chromium [Cr(VI)] biosorption property of the newly isolated actinobacterial probiont Streptomyces werraensis LD22.

The present work demonstrates the heavy metal resistance and detoxification of Cr(VI) by the probiotic actinobacterial cultures isolated from chicken and goat feces. The actinobacterial isolates were screened for heavy metal resistance by qualitative, semiquantitative assays and Cr(VI) biosorption was determined by analytical techniques such as atomic absorption spectrophotometry and Fourier transform infrared spectrometry (FT-IR). All the tested actinobacterial isolates (n = 20) showed resistance toward K2Cr2O7, NiCl2, ZnCl2, CuSO4 and PbNO3 at 20 mg L-1 concentration. The maximum tolerance concentration values were found to be 200-250 mg L-1 for K2Cr2O7, 100-250 mg L-1 for PbNO3 and <50-250 mg L-1 for NiCl2, ZnCl2 and CuSO4. Among the five tested heavy metals, Cr(VI) was resisted by 95 % of the tested actinobacterial cultures up to 250 mg L-1 concentration; particularly, the isolate LD22 exhibited a high degree of tolerance to all the tested heavy metals. Thus, the isolate was justifiably chosen for Cr(VI) biosorption study and the biosorption efficacy was found maximum at 100 mg L-1 of metal ion concentration (3 g L-1 of biomass dosage and pH 7.0). FT-IR spectrum revealed the chemical interactions between the hydroxyl, amine and carboxyl groups of the biomass and the metal ions. On the basis of phenotypic, physiological, biochemical and molecular characteristics the isolate LD22 was identified as Streptomyces werraensis LD22 (JX524481) which could be used to develop a biosorbent for adsorbing Cr(VI) metal ions.

Eugenol inhibits cell proliferation via NF-κB suppression in a rat model of gastric carcinogenesis induced by MNNG.

The modulation of intracellular nuclear factor-kappaB (NF-κB) signaling pathway involved in the deregulated expression of cell proliferation and cell cycle regulatory molecules is a pragmatic approach for chemoprevention. Eugenol (4-allyl-1-hydroxy-2-methoxybenzene), a natural phenolic constituent of oils of cloves is known to possess attractive remedial features. In the present study, we investigated the modulatory effects of eugenol on NF-κB signaling in a rat model of gastric carcinogenesis induced by N-methyl-N(')-nitro-N-nitrosoguanidine (MNNG) by analysing the expression of nuclear factor-kappaB (NF-κB) family members ((NF-κB (p50 and p65), inhibitor of kappaB alpha (IκBα), phosphorylated IκBα (p-IκBα), IκB kinase ß (IKKß)) and the NF-κB target genes that promote (e.g., cyclin D1, cyclin B and PCNA) or inhibit (e.g., p53, p21, and Gadd45) cell proliferation and cell survival. MNNG-induced gastric tumours were characterized by NF-κB activation that correlated with upregulation of IKKß, and phosphorylation and degradation of IκBα. Furthermore, upregulation of cyclins and PCNA with downregulation of p21, p53, and Gadd45 suggested that the proliferative advantage in gastric carcinomas is dependent on elevated constitutive NF-κB activity. Administration of eugenol significantly reduced the incidence of MNNG-induced gastric tumours by suppressing NF-κB activation and modulating the expression of NF-κB target genes that regulate cell proliferation and cell survival. The targeting of NF-κB signaling pathway by eugenol may have a significant impact on chemopreventive and therapeutic approaches for cancer.

The neem limonoids azadirachtin and nimbolide inhibit cell proliferation and induce apoptosis in an animal model of oral oncogenesis.

Limonoids from the neem tree (Azadirachta indica) have attracted considerable research attention for their cytotoxicity against human cancer cell lines. However, the antiproliferative and apoptosis inducing effects of neem limonoids have not been tested in animal tumour models. The present study was therefore designed to evaluate the relative chemopreventive potential of the neem limonoids azadirachtin and nimbolide in the hamster buccal pouch (HBP) carcinogenesis model by analyzing the expression of proliferating cell nuclear antigen (PCNA), p21(waf1), cyclin D1, glutathione S-transferase pi (GST-P), NF-kappaB, inhibitor of kappaB (IkappaB), p53, Fas, Bcl-2, Bax, Bid, Apaf-1, cytochrome C, survivin, caspases-3, -6, -8 and -9, and poly(ADP-ribose) polymerase (PARP) by RT-PCR, immunohistochemical, and Western blot analyses. The results provide compelling evidence that azadirachtin and nimbolide mediate their antiproliferative effects by downregulating proteins involved in cell cycle progression and transduce apoptosis by both the intrinsic and extrinsic pathways. On a comparative basis, nimbolide was found to be a more potent antiproliferative and apoptosis inducing agent and offers promise as a candidate agent in multitargeted prevention and treatment of cancer.

Evaluation of molecular markers in a rat model of mammary carcinogenesis.

We sought to evaluate the molecular markers involved in breast tumorigenesis in a rat model that mimics many essential elements of human breast cancer. Female Sprague-Dawley rats were divided into two groups. Animals in group 1 were given a single dose of 7,12-dimethylbenz[a]anthracene (DMBA) (20 mg/rat) dissolved in 1 ml of sesame oil by intragastric intubation. Group 2 animals received basal diet and served as control. We analyzed DMBA-induced changes in the expression of CYP isoforms (CYP1A1 and 1B1) involved in DMBA metabolism, markers of oxidative stress (4HNE, HEL, and 8-OHdG), cell survival and proliferation (PCNA, NF-kappaB-p50, NF-kappaB-p65, GST-P, and p53), apoptosis (Bcl-2, Bax, caspases, Apaf-1, cytochrome C, and Fas), invasion (uPA, MMP-2, MMP-9, TIMP-2, and RECK), and angiogenesis (VEGF, VEGF-R1, HIF-1alpha, and PLGF) by immunohistochemical localization, Western blot, and reverse transcriptase-polymerase chain reaction (RT-PCR) analysis. The present study demonstrates increased carcinogen metabolism, oxidative stress, cell proliferation, together with apoptosis evasion, invasion, metastasis, and neovascularization that may confer a selective growth advantage to DMBA-induced mammary tumors. Aberrant expression of multiple molecules in key signaling pathways in Sprague-Dawley rat mammary tumors renders this model as an important tool for monitoring carcinogenic progression and chemointervention.

Black tea polyphenols target matrix metalloproteinases, RECK, proangiogenic molecules and histone deacetylase in a rat hepatocarcinogenesis model.

BACKGROUND: The aim of this study was to evaluate the chemopreventive effects of black tea polyphenols (Polyphenon-B) on markers of invasion and angiogenesis during dimethylaminoazobenzene (DAB)-induced hepatocarcinogenesis. MATERIALS AND METHODS: Male Sprague-Dawley rats were divided into four groups. The rats in groups 1 and 2 were given 0.06% DAB in the diet for 3 months followed by the normal diet. The rats in group 2 received in addition 0.05% Polyphenon-B in the basal diet. The group 3 animals were given 0.05% Polyphenon-B alone in the basal diet. The group 4 animals served as the control. RESULTS: The dietary administration of DAB induced well-differentiated hepatocellular carcinomas (HCC) that showed increased expression of the markers of invasion, angiogenesis and epigenetic histone deacetylation compared with the controls. The administration of Polyphenon-B significantly reduced the incidence of DAB-induced hepatomas as evidenced by modulation of the markers of invasion (matrix metalloproteinase, MMP-2, MMP-9, tissue inhibitor of matrix metalloproteinase, TIMP-2, and reversion-inducing cysteine rich protein with Kazal motifs RECK) and angiogenesis (hypoxia inducible factor 1alpha, HIF1alpha, vascular endothelial growth factor, VEGF, and VEGF receptor, VEGFR1) as well as the expression of histone deacetylase HDAC-1. CONCLUSION: The results of the present study provide evidence that Polyphenon-B has potential as a chemopreventive agent.

Chemoprevention of rat mammary carcinogenesis by Azadirachta indica leaf fractions: modulation of hormone status, xenobiotic-metabolizing enzymes, oxidative stress, cell proliferation and apoptosis.

We evaluated the chemopreventive potential of the ethyl acetate fraction (EAF) and methanolic fraction (MF) of Azadirachta indica (neem) leaf on 7,12-dimethylbenz[a]anthracene (DMBA)-induced rat mammary carcinogenesis. Estradiol and estrogen receptor status, xenobiotic-metabolizing enzyme activities, redox status, DNA and protein modifications, and the expression of cell proliferation, and apoptosis related proteins in the mammary gland and liver were used as biomarkers of chemoprevention. Administration of both EAF and MF at a dose of 10mg/kg bw effectively suppressed tumour incidence. Chemoprevention by neem leaf fractions was associated with modulation of hormone and receptor status, xenobiotic-metabolising enzymes, and lipid and protein oxidation, with upregulation of antioxidants, inhibition of oxidative DNA damage, protein modification, and cell proliferation, and induction of apoptosis. However EAF rich in constituent phytochemicals was more effective than MF in modulating multiple molecular targets. These results provide evidence for the chemopreventive efficacy of neem leaf fractions in the rat mammary tumour model.

Evaluation of molecular markers in canine mammary tumors: correlation with histological grading.

The objective of this study was to evaluate molecular markers involved in mammary tumorigenesis in a canine model that mimics many essential elements of human breast cancer. Thirty mammary gland tumors and control tissues obtained from female dogs were included in the study. We analyzed changes in the expression of markers of hormone and receptor status (estradiol, estrogen receptor; ER and HER-2/neu), hormone metabolism (CYP1A1 and CYP1B1), cell proliferation and survival [proliferating cell nuclear antigen (PCNA), glutathione S-transferase-P (GST-P), nuclear factor-kappaB (NF-kappaB-p50, NF-kappaB-p65), phosphorylated-inhibitor of kappaB-alpha (p-IkappaB-alpha) and IkappaB], apoptosis (Bcl-2, Bax, caspases, Apaf-1, cytochrome-C, and PARP), invasion [matrix metalloproteinases-2 and -9 (MMP-2, MMP-9), tissue inhibitor of matrix metalloproteinase-2 (TIMP-2), and reversion-inducing cysteine-rich protein with Kazal motifs (RECK)], angiogenesis [vascular endothelial growth factor (VEGF)], and epigenetics [DNA methyltransferase (Dnmt-1), histone deacetylase (HDAC-1)] by immunohistochemical localization and Western blot analysis and correlated these with histological grade. The present study provides evidence that increased expression of ER, HER-2/neu, estradiol, and its metabolizing enzymes, as well as proteins involved in cell proliferation, apoptosis evasion, invasion, and angiogenesis may confer a selective growth advantage to canine mammary tumors. To our knowledge this is the first report on the hallmark capabilities of canine mammary tumors, which lends credence to the view that the dog is a valuable model for human breast cancer studies.