1,25-Dihydroxyvitamin D3 potentiates the cytotoxic effect of TNF on human breast cancer cells

Abstract

We studied the effect of 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) on the cytotoxic action of TNF on MCF-7 human breast cancer cells and on adult bovine aortic endothelial cells.

1,25(OH)2D3 increased the effect of TNF on MCF-7 cells but not on endothelial cells over a wide TNF concentration range. At a suboptimal concentration (1 ng/ml) the potentiation was twofold.

The effect of 1,25(OH)2D3 was specific, dose-dependent and apparent at a physiological concentration (0.1 nM) of the hormone.

The potentiating effect of 1,25(OH)2D3 on TNF action was abolished by cycloheximide indicating that their interaction requires protein synthesis.

Addition of 1,25(OH)2D3 13 h after TNF in a 28-h assay was sufficient to induce its full potentiating effect indicating that the hormone modulates a late event in the cytokine's action.

These data suggest that some of the in vivo antitumor effects of 1,25(OH)2D3 may be due to an increase in the anticancer activity of the immune system.

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See also:

- Vitamin D (analogues and/or derivatives) and cancer;

- Evaluation of the safety and efficacy of the first-line treatment with somatostatin combined with melatonisn, retinoids, vitamin D3, and low doses of cyclophosphamide in 20 cases of breast cancer: a preliminary report;

- The Di Bella Method (DBM) improved survival, objective response and performance status in a retrospective observational clinical study on 122 cases of breast cancer;

- Complete objective response to biological therapy of plurifocal breast carcinoma.