Chemosensitization and Radiosensitization of Tumors by Plant Polyphenols

Abstract

The treatment of cancer with chemotherapeutic agents and radiation has two major problems: time-dependent development of tumor resistance to therapy (chemoresistance and radioresistance) and nonspecific toxicity toward normal cells. Many plant-derived polyphenols have been studied intently for their potential chemopreventive properties and are pharmacologically safe. These compounds include genistein, curcumin, resveratrol, silymarin, caffeic acid phenethyl ester, flavopiridol, emodin, green tea polyphenols, piperine, oleandrin, ursolic acid, and betulinic acid. Recent research has suggested that these plant polyphenols might be used to sensitize tumor cells to chemotherapeutic agents and radiation therapy by inhibiting pathways that lead to treatment resistance. These agents have also been found to be protective from therapy-associated toxicities. How these polyphenols protect normal cells and sensitize tumor cells to treatment is discussed in this review.

Redox Control of Apoptosis: An Update

“…Among these, curcumin (2,3), and many other polyphenol derivatives (31,32,33,46,49,52,53,54) have been found to inhibit NF-B pathway in several tumor cell lines and at different levels, from I B phosphorylation to the expression of NF-B-regulated gene products. These novel findings could be of great importance in cancer prevention and therapy (27), especially in light of the latest evidence that demonstrates a pivotal role for NAD(P)H:quinone oxidoreductase 1 (NQO1) in producing ROS downstream of TNF engagement, in keratinocytes from NQO1 -/-mice (4). The genetic deletion of NQO1 used in this study abrogates the phosphorylative cascade mediated by MEKK1, which concomitantly activates I B kinase (IKK)/ NF-B signaling axis and all the members of the MAP kinase family: JNK, p38 MAPK , and p42/44 extracellular signalregulated kinase 1/2 (ERK1/2) (4).…”

Characterization and anticancer potential of ferulic acid-loaded chitosan nanoparticles against ME-180 human cervical cancer cell lines

“…Radiotherapy is the major therapeutic technique to minimize the effect of cervical cancer but due to its adverse effect on normal tissues, alternative plant-derived therapeutic drugs are being tested increasingly (Seiwert et al 2007). A large number of natural compounds have shown cytotoxic effects in different cancer models either alone or together with radiation (Garg et al 2005). Effects of FA on human cervical carcinoma cells ME-180 and HeLa have been studied and indicated that FA treatment significantly decreased radiation surviving fraction of the cancer cells and increased the lipid peroxidation indices (Subburayan et al 2011).…”

trans-Resveratrol induces apoptosis in human breast cancer cells MCF-7 by the activation of MAP kinases pathways

“…Among nutraceuticals, polyphenols represent the most intriguing and studied class of compounds that can be therapeutics for a large spectrum of the most common diseases including cancer [20]. Nevertheless, despite several studies regarding their function, the anti-oxidant/prooxidant properties of these compounds remain somewhat debatable and the detailed molecular mechanisms of their effects continue to be largely unknown.…”