Epstein-Barr virus early antigen activation

Azuine MA, Tokuda H, Takayasu J, et al. (2004) Cancer chemopreventive effect of phenothiazines and related tri-heterocyclic analogues in the 12-O-tetradecanoyl-phorbol-13-acetate promoted Epstein-Barr virus early antigen activation and the mouse skin two-stage carcinogenesis models. Pharmacology Research 49 161-169. 

Tetradecanoylphorbol 13-acetate (TPA) and other diterpene esters from the plant family Euphorbiaceae are well-known as tumor-promotion agents [85]. Thus, inhibition of the biological effects induced by TPA has been considered as a promising strategy [68]. To date, two short-term cell-based in vitro bioassays using TPA as a tumor-promoter have been developed to evaluate the potential cancer chemopreventive activities of several lignans isolated from Hernandia species, namely, inhibition of Epstein-Barr virus early antigen activation [6] and the inhibition of the transformation of JB6 mouse epidermal cells [7]. 

Ailantinol G (43) a quassinoid isolated from Ailanthus altissima was evaluated for its antitumor effects promotion against Epstein-Barr virus early antigen activation introduced by 12-0-tetradecanoylphorbol-13-acetate in Raji cells [25],... 

The effect on EBV- EA (Epstein-Barr virus early antigen) activation of compounds 172 and 210-217, were also examined. Their inhibitory effects on the activation of the early antigen and the viabilities of Raji cells are shown in Table 12. Compounds 172, 210, 216 and 217 showed stronger activities than the other compounds. 

A test of inhibitory effects on Epstein-Barr virus early antigen activation in Raji cells induced by a combination of n-butylic acid and 12-0-tetradecanoylphorbol-13-acetate (TPA) has been employed (EBV-EA test) as a simple primary screening for antitumor promoting agents. In this test, significant inhibitory effect was observed for astilbin and its isomers as well as (+)-taxifolin. Of these dihydroflavonol derivatives, neoastilbin showed the strongest activity. 

Inhibitory Effects on Epstein-Barr virus Early Antigen Activation... 

Kapadia, G.J., M.A. Azuine, H. Tokuda, et al. 2002. Inhibitory effect of herbal remedies on 12-0-tetradecanoylphorbol-13-acetate-promoted Epstein-Barr virus early antigen activation. Pharmacol. Res. 45(3) 213-220. 

Kapadia GJ, Azuine MA, Tokuda H, Takasaki M, Mukainaka T, Konoshima T, Nishino H (2002) Chemopreventive effect of resveratrol, sesamol, sesame oil and sunflower oil in the Epstein Barr virus early antigen activation assay and the mouse skin two-stage carcinogenesis. Pharmacol Res 45 499... 

Epstein-Barr virus early antigen induction. Methanol extract of the dried leaf, in cell culture at a concentration of 1 pg/mL, was inactive. The assay was designed for tumor-promoting activity . Two diastere-oisomers of 2,7,1 l-cembratriene-4,6-diol (a- and 3-CBT) from the neutral fractions of cigarette smoke condensate, in Raji cells, produced potent inhibitory effects on the induction of Epstein-Barr virus (EBV)-EA by 12-0-tetradecanoylphorbol-13-acetate (TPA). The doses of a- and P-CBT required for 50% inhibition of EBV-EA induction by TPA were 7.7 and 6.7 mg/mL, respectively. Application of a- and P-CBT to mouse skin before treatment with TPA, inhibited TPA-induced ornithine decarboxylase activity in a dose-dependent manner. Application of 16.5 pM/mouse of a- and p-CBT resulted... 

EBV Inhibition of Epstein-Barr virus early antigen (EBV-EA) activation induced by TPA [22-27]... 

Ethanolic extract (50%) of M. oleifera (whole plant excluding roots) shows anti-cancer activity in mice (50). Evaluation of the anticancer potential of 11 plants used in Bangladeshi folk medicine has shown that, only three extracts, among which M oleifera, is considered as a potential source of anticancer compounds (56). Crude ethanol extract of M. oleifera dried seeds inhibits the formation of Epstein-Barr virus-early antigen (EBV-EA) induced by 12-0-tetradecanoylphorbol-13-acetate. At a dosage of 100 pg/mL, the extract inhibits EBV-EA formation by 100% suggesting its antitumor-promoting activity (99). 

Four of the isolates (2), (3), (7) and (8) showed inhibitory activity against Epstein-Barr virus-early antigen (EBV-EA) activation with compounds (2), (3) and (8) having very significant activities (53), indicating higher potential for antitumor activities. Most compounds that inhibit in vitro EBV-EA activation are also known to be antitumor promoters in vivo (12). Niazimicin (3) when... 

The studies were carried out on a primary screening test using their inhibitory effects on Epstein-Barr virus early antigen (EBV-EA) activation induced by 12-O-tetradecanoylphorbol- 13-acetate (TPA), a strong promoter, in Raji cells. 

Procyanidin B2 (dimer), isolated from loquat leaves, was found to inhibit the 12-0-tetradecanoylphorbol-13-acetate (TPA)-induced activation of Epstein-Barr virus early antigen in Raji cells [108]. Animal studies and cell models suggest that flavonoids act as anticarcinogens through influencing molecular events in the initiation, promotion, and progression stages of cancer [109]. 

Tocotrienols, which are found at particularly high levels in rice bran oil, cranberry oil, palm oil and barley oil, also have unique biological properties distinct from those of tocopherols. Goh etal. (1994) used an in vitro assay of the activation of Epstein-Barr virus early antigen expression in human lymphoblastoid cells to study the ability of tocotrienols and tocopherols to prevent tumor promotion. Their results showed that y- and 5-tocotrienols, but... 

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