TPA-stimulated

HeLa TPA-Stimulated 32Pi incorporation in HeLa cell inhibition [28,29,39]... 

Inhibitory Effects on TPA Stimulated 32Pi Incorporation in HeLa Cells... 

Apigenin and other related flavonoids inhibited carcinogen-induced tumors in rats and mice. Apigenin suppressed TPA-induced tumor promotion of mouse skin. Apigenin also reduced the level of TPA-stimulated phosphorylation of cellular proteins and inhibited TPA-induced c-jun and c-fos expression. Tss... 

Studies of the methanolic extract of Alpinia oxyphylla have shown that this extract suppresses the promotion of skin tumors in mice and that it induces apoptosis in cultured human promyelocytic leukemia cells. In addition, two phenolic diarylheptano ids isolated from the active extract, yakuchinone A and yakuchinone B, were found to ameliorate tumor promotion as well as inhibit both TPA-induced epidermal ornithine decarboxylase (ODC) activity and ODC RNA expression. Moreover, yakuchinones A and B reduced production of the TNF-a in the TPA-stimulated skin of mice. Furthermore, both compounds inhibited the TPA-induced expression of COX-2 at both transcriptional and... 

We then examined the inhibitory effects of nobiletin on differentiated HL-60 cells, known to generate 02 - with TPA stimulation and compared them with those of luteolin. As shown in Figure 6, nobiletin exhibited a much higher level of inhibition than luteolin, while the IC50 value of nobiletin (1.2 pM) was approximately 8 times lower than that of luteolin (9.8 pM). Because nobiletin did not significantly scavenge O2 generated from the xanthine/xanthine oxidase system nor inhibited xanthine oxidase activity up to a concenPation of 500 pM (data not shown), it may inhibit the assembly or activity of multicomponent NADPH oxidase system in differentiated HL-60 cells. 

Suppresses pro-matrix metalloproteinase- TPA-stimulated 9, progelatinase-B, interstitial Eff-lOSO cells... 

Protection by 3-aminobenzamide is not mediated by an inhibition of ADP-ribosylation. At high concentrations (20 mM), benzamide and analogs inhibited 0 production from TPA-stimulated granulocytes, whUe die corresponding acids did not (Table 1). However, when analyzed in the cytotoxicity test, it was foimd that benzamide and nicotinamide at 2.5 mM concentrations did not prevent but enhanced cytotoxicity. This pointed to a special scavenger function of ABA in the prevention of cell damage as induced by reactive oxygen species. Protection by ABA was also observed... 

Table 1. Inhibition of O2 production from TPA-stimulated human granulocytes by inhibitors of poly(ADP-ribose) polymerase.

ROS scavenging ability of ERG was tested using 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) solution-based chemical assay and a 2,2,7,2-dichlorodihydrofluorescein diacetate (DCFH-DA) HL-60 cell line-based assay. The cell-based fluorescent DCFH assay enables detection of antioxidant molecules which can penetrate cell membranes and inhibit ROS production in living cells. The antioxidant activity was determined by TPA-stimulated control cells with and without FRG. FRG showed strong antioxidant activity in both systems [64]. 

The cascade of the second messenger system for histamine release in the ECL cell has not been characterized. Isolated ECL cells studied in a perfusion chamber exhibit a biphasic increase in intracellular calcium when exposed to gastrin or PACAP. An early transient, presumably due to the release of calcium from intracellular stores, is followed by a steady-state increment due to caldum entry. Blockade of caldum entry by La blocks histamine release. It is likely that the increase in cell calcium causes the activation of a variety of calcium-dependent signaling pathways, including protein kinase C. The C kinase activator, the phorbol ester tetradecanoyl-13-phorbol acetate (TPA) stimulates histamine release, supporting the proposal that this protein kinase is a component of the calcium-dependent histamine-stimulation pathway. Because forskolin (an intracellular stimulant of adenylate cyclase) is also a potent agonist of histamine release, a role for cAAAP in histamine secretion is likely. This proposal is supported by increased cAMP levels in forskolin-stimulated ECL cells. 

---