vitamin D3 as a natural breast cancer preventative

[Lani]

they have found that the enzyme which converts other forms of 25 OH-D3 to 1,25 OH D3 the final active product, is not only present in the kidneys, but ALSO IN THE BREAST CELLS THEMSELVES, making this possible:

1: Breast Cancer Res Treat. 2008 Jan 20 [Epub ahead of print]
25-Hydroxyvitamin D(3) is a natural chemopreventive agent against carcinogen induced precancerous lesions in mouse mammary gland organ culture.

Peng X, Hawthorne M, Vaishnav A, St-Arnaud R, Mehta RG.
IIT Research Institute, 10 West 35th Street, Chicago, IL, 60616, USA, rmehta@iitri.org.
Despite the role of vitamin D(3) endocrine system in prevention of mammary gland transformation in animal models, use of 1,25(OH)(2)D(3 )in clinical settings is precluded due to its toxicity in vivo. Therefore much effort has been placed in developing relatively non-toxic vitamin D analogs. Recently, with the discovery of the expression of 25-hydroxy vitamin D(3) 1alpha-hydroxylase (CYP27B1) in multiple extrarenal organs, the functional role of prohormone, 25-hydroxyvitamin D(3) [25(OH)D(3)], has been redefined. Since 25(OH)D(3) does not cause hypercalcemia and maintains relative high concentration in serum, it is possible that the prohormone can be converted to active hormone in mammary epithelial cells to provide chemopreventive effects. In the present study, we evaluated its functional significance using mouse mammary organ culture (MMOC) system. We first showed that 25(OH)D(3) 1alpha-hydroxylase is extensively expressed in mammary ductal epithelial cells at both protein and mRNA levels, which is a prerequisite for 25(OH)D(3) to function in an autocrine/paracrine manner. However, we also observed that clotrimazol (1alpha-hydroxylase inhibitor) enhanced 25(OH)D(3) -induced CYP24 expression in breast cancer cells. In mammary glands derived from 1alpha-hydroxylase knockout mice, 25(OH)D(3) treatment in organ culture significantly induced CYP24 expression, indicating a potential direct effect of 25(OH)D(3). In MMOC, 100-250 nM 25(OH)D(3) suppressed both ovarian hormone-dependent and -independent mammary precancerous lesions (induced by DMBA) by more than 50%, while the active hormone 1,25(OH)(2)D(3) (positive control) at 100 nM suppressed alveolar lesions by more than 80%. The inactive vitamin D(3) (negative control) at 100 nM suppressed alveolar lesions by only 20% (P > 0.05). We found that 25(OH)D(3) inhibits DMBA-induced mammary alveolar lesions (MAL) in a stage-specific manner: 25(OH)D(3) mainly inhibits the promotion stage of lesion formation. We conclude that 25(OH)D(3) could serve as a non-toxic natural chemopreventive agent for further development for breast cancer prevention.
PMID: 18205042 [PubMed - as supplied by publisher]

[Mary Jo]

Thanks Lani....I've been very interested in D3 and find it's findings very promising. I just had my D3 levels checked and they came in at 39. The range is 25 - 80. I'd rather be closer to the 80 mark. I've discontinued taking my calcium as I worried about getting to much of that BUT have increased my D3. I now take a little over 5000 i.u. of this "wonder drug" and will have my levels checked again as I don't want toxicity to occur ALTHOUGH I don't feel that amount would do it.

Any more information you have to share on D3 and amounts I'd appreciate.

As always Lani - THANK YOU! You invaluable to us.

Mary Jo

[Linda]

Thanks Lani, and hi Marejo!
As Marejo knows, my onc has me on major D3 supplements and wants my level to always be at the high end of normal. Good to get some confirmation on this.
Linda