1,25-Dihydroxyvitamin D3 suppresses cell growth, DNA synthesis, and phosphorylation of retinoblastoma protein in a breast cancer cell line

Abstract

Cells of a breast adenocarcinoma cell line, CAMA-IEe, were found to contain a moderate concentration of 1,25-dihydroxyvitamin D3[1,25(OH)2D3] receptors.

The receptors' dissociation constant calculated by Scatchard analysis was 4.1 x 10(-10) M. These receptors sedimented at around 4.0 S position on a linear 5-20% sucrose density gradient and exhibited an apparent molecular weight of about 46 kDa.

Receptor concentration was found to be highest in the early stages of cell growth, decreased continuously when cells were actively growing, and reached the lowest level at confluence.

Suppression of cell growth, of DNA synthesis, and of the phosphorylation of retinoblastoma protein by 1,25(OH)2D3 at concentrations about 10(-7) M were observed.

Treatment with 10(-7) M 1,25(OH)2D3 for 12 hr or longer caused elevation of cytosolic free calcium in CAMA-IEe cells.

These results show that CAMA-IEe cell growth is suppressed by 1,25(OH)2D3 and that the suppression is possibly mediated through calcium mobilization.

 

 

About this publication.

 

See also:

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

- Congenital fibrosarcoma in complete remission with Somatostatin, Retinoids, Vitamin D3, Vitamin E, Vitamin C, Melatonin, Calcium, Chondroitin sulfate associated with low doses of Cyclophosphamide in a 14-year Follow Up;

- Chronic Lymphocytic Leukemia: Long-Lasting Remission with Combination of Cyclophosphamide, Somatostatin, Bromocriptine, Retinoids, Melatonin, and ACTH;

- 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.