Rumination: Is The Beneficial Effect Of Exercise On Bc Due To The Sun Exposure/vit D?

[Lani]

SINCE MOST OF THE STUDIES CENTERED ON WALKING (AND FEW FEMALES WALK AT NIGHT IN MANY AREAS OF THE US AS IT IS UNSAFE/UNWISE), COULD MOST/ALL OF THE BENEFICIAL EFFECT BE DUE TO THE FACT THAT IT INCREASES EXPOSURE TO SUNSHINE AND HENCE VITAMIN D?

HERE IS THE ARTICLE WHICH MADE ME THINK (AGAIN ABOUT THIS AND POSE IT TO OTHERS):

ABSTRACT: Prohibitin Is a Novel Target Gene of Vitamin D Involved in Its Antiproliferative Action in Breast Cancer Cells [Cancer Research; Subscribe]
Previously, we showed that N-methyl-N-nitrosourea-transformed MCF12F breast epithelial cells exhibited differential expression of several genes, including up-regulation of prohibitin and elevated sensitivity to a relatively noncalcemic vitamin D analogue, 1?-hydroxyvitamin D5 [1?(OH)D5]. In this report, we evaluated the functional significance of prohibitin in relation to the cellular response to vitamin D. The in silico screening for putative transcription factor binding sites identified two vitamin D receptor (VDR)/retinoid X receptor binding sites in the 1-kb promoter region of prohibitin. Prohibitin up-regulation by 1?(OH)D5 treatment at both transcriptional and translational levels was confirmed by real-time reverse transcription-PCR and Western blot analysis in breast cancer cells, identifying prohibitin as a vitamin D target gene. Confocal microscopic analysis showed that prohibitin was localized in the nuclei of MCF-7 cells and a portion of prohibitin was colocalized with VDR, but direct physical interaction between VDR and prohibitin in cell lysates was not detectable. In MCF-7 cells expressing tetracycline-inducible prohibitin (Tet-On model), the overexpression of prohibitin inhibited cell proliferation and enhanced vitamin D-induced antiproliferative activity. Knockdown of prohibitin was accompanied by increased number of cells incorporating bromodeoxyuridine in the whole population and increased cell distribution in the S phase of cell cycle. In addition, prohibitin level had no significant effect on the vitamin D-induced transactivation of CYP24, a VDR target gene. This is the first report to suggest that prohibitin serves as a novel vitamin D target gene, which is involved in the antiproliferative action of vitamin D without affecting CYP24 transactivation in breast cancer cells.

[Becky]

I believe this could be part of it but another part could clearly be IGF and IGF receptors. It is clear that exercise affects insulin resistance pathways (making insulin more recognized and reducing the effects of metabolic syndrome) so...


If one is experiencing insulin resistance, the liver puts out large quantities of IGF in order to force the pancreas to put out more insulin (which is further not recognized). It's a complete merry go round. Many cancers, including breast, can have IGF receptors so they could grow faster in response to more IGF being put out. Exercise stops this merry go round (helps insulin be recognized by the body, helps reverse metabolic syndrome, therefore reduces the extra/non stopping output of IGF by the liver).

But I agree, I walk in the sunshine if I can (can't during the work week right now so I go at night but get outside at lunch time)

Another thought (for HR+ cancers) is that exercise can reduce (or at least maintain) weight and adipose tissue produces estrogen. Estrogen + cancer can grow or cells be stimulated by estrogen. More fat, more estrogen, more growth.

Just thinking out loud here.

Kind regards

Becky

[Bev]

But could you be fit and tan and still be pre-diabetic or having estrogen overload? I know we've talked about this before. There's just a large number of us of us fit and tan on this board. These things may figure in for the whole breast cancer population. I just think it's not as big a factor for HER2+. Something else is going on.

Thanks always, as I love to read the studies. They give us hope and things to try to improve the odds. Heck, I'll go into the sun or take supplements if they show an improvement. I just think there's something diet and exercise independant going on for premenopausal HER+. Hope they find out soon. BB.

[heblaj01]

An additional benefit of exercising may be the increase in endostatin, the natural endogenous antiangiogenesis molecule which may help fight cancer:

http://www.pubmedcentral.nih.gov/art...i?artid=324413
Exercise increases endostatin in circulation of healthy volunteers

[Bev]

I guess what I'm saying is that there can be genetic and environmental boo-boos that can't overcome the positives granted thru diet and exercise. Can't hurt to try diet and exercise. I'm feeling let down from my years at the Y and walnuts on my mixed greens. BB, ps BB stands for Bad Bev.