I’ve just recently joined this forum. I would like to comment briefly on the nicotinamide riboside and NAD+, sirtuin, etc., thread.
Maybe I missed something somewhere, but in the curated threadI’ve only seen passing references to the extensive literature on well-studied negative effects of elevated NAD+ and sirtuin levels, especially in the case of cancer initiation, progression, and metastasis.
You certainly never find detailed discussions of this issue with Guarente or Sinclair or any of the others with deep nvolvement in selling NAD+ precursors or intermediates or putative sirtuin activators. How many hundreds of millions of dollars (!) did Sinclair make in pushing resveratrol by a little tweaking of the research?
But there are others outside this group who have published a long series of papers on NAD+ and cancer. The problem with all these wishful-thinking anti-aging magic bullets (in the decades I’ve followed the field there has been a long list — the most hyped these days including metformin, rapamycin, NAD+ and its relatives, the sirtuins — is that all are intensively pleiotropic.
And all that means is that they have many, in some cases many hundreds, of contradictory effects in different parts of the body, in different tissues, and sometimes in different cellular compartments of the body, as is the well-known case of the sirtuins.
I could post a dozen or more links to papers on cancer and upregulated NAD+, which the Guarente or Sinclair types only mention quickly, and in passing, but as I understand it I can’t post links in the List yet as a new member. But a good place to start is with this review by Shackelford et al. published in _Genes and Cancer_ in 2013. It deals with Nicotinamide Phosphoribosyltransferase (Nampt). Nampt is part of the catalytic chain that produces nicotinamide mononucleotide, a key step in the synthesis of NAD+.
Here I just post the abstract, since I can’t apparently post links, but you can get the whole paper, which is open access, by putting the title into PubMed.
Also see the further warnings (esp. on p. 1213) about autoimmune activation and cancer involving NAD and its relatives in the 2015 review of NAD+ in _Science_ by Eric Verdin, of UCSF, who also has no financial interest (unlike the Sinclair or Guarente types) in research in this field:
"NAD+ in aging, metabolism, and neurodegeneration,” Science. 2015 Dec 4;350(6265):1208-13. doi: 10.1126/science.aac4854
Best,
Genji
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Nicotinamide Phosphoribosyltransferase in Malignancy:A Review
Rodney E. Shackelford1, Kim Mayhall2, Nicole M. Maxwell3, Emad Kandil2, and Domenico Coppola4
Submitted 19-Jun-2013; accepted 26-Aug-2013
Abstract
Genes & Cancer
4(11-12) 447–456
DOI: 10.1177/1947601913507576
Nicotinamide phosphoribosyltransferase (Nampt) catalyzes the rate-limiting step of nicotinamide adenine dinucleotide (NAD) synthesis. Both intracellular and extracellular Nampt (iNampt and eNampt) levels are increased in several human malignancies and some studies demonstrate increased iNampt in more aggressive/invasive tumors and in tumor metastases. Several different molecular targets have been identified that promote carcinogenesis following iNampt overexpression, including SirT1, CtBP, and PARP-1. Additionally, eNampt is elevated in several human cancers and is often associated with a higher tumor stage and worse prognoses. Here we review the roles of Nampt in malignancy, some of the known mechanisms by which it promotes carcinogenesis, and discuss the possibility of employing Nampt inhibitors in cancer treatment.
Keywords
nicotinamide phosphoribosyltransferase, nicotinamide adenine dinucleotide, human cancer