Stereoisomers of cysteine and its analogs Potential effects on chemo- and radioprotection strategies

Abstract

The thiol-containing amino acid, cysteine, and its analogs are useful for a variety of protective applications, including protecting normal tissues against the unwanted side effects of cancer chemotherapeutic agents and radiation treatment. The protection can result from both direct action of the amino acid and/or after its conversion to glutathione (GSH), sulfate, or other sulfur-based protective substances. Unfortunately, high GSH levels have been implicated in the problematic development of tumor cells' resistance to therapy. Due to numerous differences in the metabolic processing of the cysteine stereoisomers, chemo- and radioprotective strategies might be developed using the D-form of the amino acid, which can participate in protection directly, but which cannot be used to support GSH biosynthesis. In this way, protection of normal tissue may be achieved, while the potential development of resistance in tumor cells is minimized. Greatly enhanced therapeutic efficacy of cancer treatment regimens may be the result.

Vanadium: History, chemistry, interactions with α-amino acids and potential therapeutic applications

“…The nature of the ligands may play an important role in the selectivity, potency and type of biological activity exerted by vanadium complexes. In the case of amino acids as ligands, they may have an additional effect of interest, such as L-cysteine which is a known chemoprotector [219,220], or other amino acids that have been reported to produce or contribute to the antitumor effect [220]. An excellent example is represented by glycine, which has been studied for its anti-inflammatory and cytoprotective properties, Bruns et al (2014) show that glycine inhibits angiogenesis in human hepatocellular carcinoma cells culture, through decrease VEGF-A expression [221,222].…”

Natural Radioprotective Agents: An Overview

“…Cysteine, the prototype of natural radioprotective agents protects DNA against damage induced by γ-irradiation [124]. It may also be gainfully employed as an adjuvant in radiotherapy [125] and has the potential to protect against radiation induced hair loss [126]. A patented formulation of encapsulated cysteine is available for application as a radioprotector [127].…”

In Vitro Investigation of D- and Lenantiomer Synergistic Efects of Some Amino Acids

“…The administration of L-Cys caused an increase the concentration of sulfate in the urine (about 33 % of the dose) as well as the concentration of taurine in the serum (KRIJGSHELD et al, 1981;FRIEDMAN and GUMBMANN, 1984). Other studies have showed that D-Cys has beneficial effects in acute alcohol intoxication and in cancer therapeutics and it shows no mutagenicity for humans (GLATT and OESCH, 1985;TSUKAMOTO et al, 1990;ROBERTS, 1995;OANCEA and FORMAGGIO, 2008).…”