Modulation of cell signals

In the case of a potential benefit of flavonoids in the development of cancer, these compounds may be active in the modulation of cell signaling by ... 

Modulation of Cell Signals by Flavonoids at the Membrane Level 124... 

To fully understand the actual mechanism of action of dietary flavonoids either as antioxidants, modulators of cell signalling, or inflammatory pathways, it is important to detect and identify their metabolites in vivo as well as to study the consequences of interaction of these circulating metabolites with cells. Animal models and human studies should also be conducted to identify the in vivo mechanism of action of dietary flavonoids. Results of such studies are crucial in the evaluation of their potential as cardiovascular protective agents and may eventually lead to specific advice regarding intake of foods and beverages rich in flavonoids and attempts to alter and enhance flavonoid content of a range of foods. 

West, J.D. and Marnett, L.J. (2006) Endogenous reactive intermediates as modulators of cell signaling and cell death. Chem. Res. Toxicol., 19, 173-194. 

MODULATION OF CELL SIGNALING RESULTING IN ANTIPROLIFERATIVE AND PRO-APOPTOTIC EFFECTS... 

The mechanisms which are causing the biological effects of flavanols include the modulation of cell signaling pathways [95] and the regulation of nitric oxide (NO) homeostasis, which in turn influences the flow-mediated dilation in capillaries. The antioxidative potential of the flavanols leads to scavenging free radicals and inhibits lipid peroxidation [96]. 

Several studies indicate that catechins and procyanidins are powerful scavengers of ROS. Some findings regarding the antioxidant activity of proanthocyanidins are listed in Ref. [100]. Other antioxidant mechanisms are the chelation of transition metals, as well as the mediation and inhibition of enzymes. The metal-chelating activity of proanthocyanidins is thought to be due to their capacity to reduce the concentration, and thus the oxidative activity, of hydroxyl radicals formed by Fenton reaction catalyzed by iron or copper. Flavanols also influence oxidative stress via enzyme modification and modulation of cell signaling pathways the extent of the effect relies greatly on flavanol structure-related protein reactivity [101]. 

Moyer, M L., Borror, K. C, Bona, B. J., DeFranco, D B., and Nordeen, S K. (1993) Modulation of cell signaling pathways can enhance or impair glucocorti-coid-Induced gene expression without altering the state of receptor phosphorylation. J Biol Chem 268, 22,933-22,940. 

Bertram, J.S., 2008. Modulation of Gene Expression by Dietary Carotenoids and Retinoids Role in Cancer Prevention. In Dong, Z. Surh, Y. J. (Eds ). Dietary Modulation of Cell Signaling Pathways. CRC Press, 315-336. 

Phosphorylation is the reversible process of introducing a phosphate group onto a protein. Phosphorylation occurs on the hydroxyamino acids serine and threonine or on tyrosine residues targeted by Ser/Thr kinases and tyrosine kinases respectively. Dephosphorylation is catalyzed by phosphatases. Phosphorylation is a key mechanism for rapid posttranslational modulation of protein function. It is widely exploited in cellular processes to control various aspects of cell signaling, cell proliferation, cell differentiation, cell survival, cell metabolism, cell motility, and gene transcription. 

Wood, K. W Samecki, C., Roberts, T. M and Blenis, J. (1992). ras mediates nerve growth factor receptor modulation of three signal-transducing protein kinases MAP kinase, Raf-1, and RSK. Cell 68 1041-1050. 

Palozza, R, Serini, S., Di Nicuolo, R, and Calviello, G. 2004b. Modulation of apoptotic signalling by carotenoids in cancer cells. Arch Biochem Biophys 430 104-109. 

Kannan MS Modulation of calcium signaling by interleukin-13 in human airway smooth muscle role of CD38/cyclic adenosine diphosphate ribose pathway. Am J Respir Cell Mol 9 Biol 2004 31 36-42. 

The time modulation of transmitter signals, through pulsations of different durations and shapes may lead to frequency and amplitude coding of signalling events, the detection requiring molecular receivers suitably tuned to frequency patterns and thresholds. Such processes occur in intercellular communication by cell to cell signalling [8.243]. 

Hwang JT, Kwak DW, Lin SK, Kim HM, Kim YM, Park OJ. 2007. Resveratrol induces apoptosis in chemoresistant cancer cells via modulation of AMPK signaling pathway. Ann N Y Acad Sci 1095 441-448. 

In addition to these downstream enzymatic effectors, IFs interact with receptors in the death pathway. K8 and K18 interact directly with the cytoplasmic domain of tumor necrosis factor receptor 2 (TNFR2) and attenuate TNF-induced, Jun NH(2)-terminal kinase (JNK) signaling, NFkB activation, and cell death (Gaulin et al, 2000). Modulation of cell... 

The excited iodine atom produced in reaction (18a) absorbs one or two photons to yield the I+ ion. The Xe pressure in the third harmonic cell is adjusted so that the one-and three-photon signals are approximately equal. Variation of the H2 pressure in the phase-tuning cell produces the sinusoidal variation of the ion signals shown in Fig. 6. Evident in this figure is a phase lag of 150° between the two products, HI+ and I. Also shown is modulation of the signal produced by photoionization of H2S, which provides a reference phase for the HI+ and I+ signals. 

Zhu, W.Z., Zheng, M., Koch, W.J., Lefkowitz, R.J., Kobilka, B.K., and Xiao, R.P. 2001. Dual modulation of cell survival and cell death by p2-adrenergic signaling in adult mouse cardiac myocytes. Proc. Natl. Acad. Sci. USA 98 1607-1612. 

---