Selenium: An Inhibitor of Tumor Growth in Vitro and in Vivo
Poirier, Kenneth Allen
This item is only available for download by members of the University of Illinois community. Students, faculty, and staff at the U of I may log in with your NetID and password to view the item. If you are trying to access an Illinois-restricted dissertation or thesis, you can request a copy through your library's Inter-Library Loan office or purchase a copy directly from ProQuest.
Permalink
https://hdl.handle.net/2142/77443
Description
Title
Selenium: An Inhibitor of Tumor Growth in Vitro and in Vivo
Author(s)
Poirier, Kenneth Allen
Issue Date
1984
Department of Study
Food Science
Discipline
Food Science
Degree Granting Institution
University of Illinois at Urbana-Champaign
Degree Name
Ph.D.
Degree Level
Dissertation
Keyword(s)
Health Sciences, Nutrition
Language
eng
Abstract
Tumor growth in Swiss ICR mice inoculated with 5 x 10('5) Ehrlich ascites tumor (EAT) cells was completely inhibited by intraperitoneal administration of 20 (mu)g selenium as Na(,2)SeO(,3) given 8 times over an 18 day period. This regimen did not affect growth in non-tumor-bearing mice. Sodium selenite was the most effective modulator of EAT cell growth in vivo (Na(,2)SeO(,3) >> Na(,2)Se, (Ch(,3))(,2)Se, Se-cystine) and of EAT cell viability in vitro (Na(,2)SeO(,3), SeO(,2) > Se-methionine, Se-cystine > Na(,2)SeO(,4)). Initiation of multiple selenium treatment had to be undertaken no later than 3 days following tumor cell inoculation. Single treatments of selenium were only moderately effective in inhibiting EAT growth when administered immediately following tumor cell inoculation.
Dietary selenium had a variable response on tumor incidence and survival time in EAT-bearing mice. Selenium had no effect on EAT incidence in mice fed purified L-amino acid diets supplemented with up to 5.0 ppm selenium as selenite. However, survival time was significantly increased in EAT-bearing mice fed a torula yeast diet supplemented with 2.5 or 5.0 ppm selenium as selenite. Gastric gavage of Na(,2)SeO(,3) similarly prolonged survival time in mice. However, intraperitoneal administration of Na(,2)SeO(,3) was three to four times more effective in prolonging survival time than either dietary or gavage administration.
Glutathione perioxidase activity was increased in both liver and EAT cells of mice fed selenium supplemented diets. However, this increased activity did not account for the observed inhibitory effect of selenium on EAT cell growth. Glutathione, reduced and oxidized, was not altered by selenium supplementation in vivo or in vitro. RNA, DNA, protein, and lipid levels in EAT cells were not altered by selenium treatment. However, RNA biosynthesis was decreased in both EAT and canine mammary tumors in vitro by Na(,2)SeO(,3). Selenodiglutathione (GSSeSG), a metabolite of selenium reduction, also significantly decreased RNA biosynthesis in EAT. GSSeSG was more effective than Na(,2)SeO(,3) in increasing the survival time of EAT-bearing mice and decreasing proliferation of SV 40 3T3 cells in vitro. This effect was not observed by other selenium, sulfur, or thiol containing compounds. It was concluded that the action of selenium on tumor cell propagation in vivo and in vitro was modulated at least in part through its reductive metabolite, selenodiglutathione.
Use this login method if you
don't
have an
@illinois.edu
email address.
(Oops, I do have one)
IDEALS migrated to a new platform on June 23, 2022. If you created
your account prior to this date, you will have to reset your password
using the forgot-password link below.
