Hi Jitendra, do you know of studies showing that S-nirososo albumin has an effect in a cancer model?
Nitric oxide is supposedly carried around in the circulation by serum albumin as an S-nitroso adduct.
http://www.pnas.org/content/89/16/7674.full.pdf
Are you implying that inhibiting nitric oxide binding to serum albumin can inhibit angiogenesis or metastasis?
Hello Dr. Steingrimur! Thanks for your reply
While I am tyro in this field, I recently read a paper on antitumor effect of S-niroso albumin via autophagy. So I thought of taking the opinion, if more research had been going iledon in this field. The paper is "Poly-S-nitrosated human albumin enhances the antitumor and antimetastasis effect of bevacizumab, partly by inhibiting autophagy via the generation of nitric oxide. ( Ishima Y et al., Dec 2nd 2014)"
thanks and regards
Jitendra
Hi Jitendra, I cant find the paper, but there might be many things going on here.
Serum albumin is the major carrier of drugs in circulation. If small drugs do not bind to albumin, than they will be filtered by the kidney quickly and excreted.
1) S-nitroso albumin is not binding NO.
2) S-nitroso albumin is binding bevacizumab better than native albumin.
3) Combination of 1) and 2) are enhancing the antitumor effect of the drug.
Plus HSA will not evoke immune response thus extending the circulation time of anticancer drug attached to it.
S-nitrosoalbumin (S-NOAlb) was postulated to serve as a physiological carrier for NO. The bond S-NO is relatively labile and NO can be released from S-NOAlb by the reaction with thiols or other reducing agents. As a result, anticancer effect of S-NOAlb (if any) would be likely associated with the release of NO. This is consistent with what the authors of the paper refer to as "inhibiting...via the generation of nitric oxide". Also, under biologically relevant conditions, the amount of S-NOAlb is very low relative to native serum albumin so it is not likely that the binding capacity for bevacizumab or any other drug will be affected. Converting significant proportion of serum albumin to S-NOAlb to modulate its ability to bind other drugs in clinical practice would be impractical or inconsistent with life.
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