Retinoic acid nuclear receptor alpha(RAR alpha) plays a major role in retinoid-mediated inhibition of growth in human breast carcinoma cells

Abstract

Retinoids mediate their actions via retinoic acid receptors (RARs) and retinoid X receptors (RXRs). Each of class of these nuclear retinoid receptor is further subdivided into three species namely alpha, beta and gamma.

Recently studies demonstrated that estrogen receptor (ER)-positive human breast cancer (HBC) cell lines are sensitive and ER-negative cell lines are resistant to growth inhibitory effects of retinoic acid (RA).

In this study, we found that only RAR alpha mRNA levels was strongly correlated with ER-status.

To further investigate the major role of RAR alpha in retinoid-mediated inhibition of growth, we transfected RAR alpha cDNA into two RA-resistant ER-negative HBC cell lines.

Analysis of different clonal populations of RAR alpha transfectants from each cell line revealed growth inhibition by retinoids.

Our results demonstrated that RAR alpha plays a major role in mediating retinoids inhibition of growth in HBC cells and adequate levels of RAR alpha are required for such an effect.

 

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See also:

- All-Trans-Retinoic Acid (ATRA - analogues and/or derivatives);

- The Di Bella Method (A Fixed Part - All-Trans Retinoic Acid, Analogues and/or Derivatives);

- Solution of retinoids in vitamin E in the Di Bella Method biological multitherapy;

- The Di Bella Method (A Fixed Part - Alpha tocopheryl acetate/Vitamin E);

- The Di Bella Method (DBM) in the treatment of prostate cancer: a preliminary retrospective study of 16 patients and a review of the literature;

- The Synergism of Somatostatin, Melatonin, Vitamins Prolactin and Estrogen Inhibitors Increased Survival, Objective Response and Performance Status In 297 Cases of Breast Cancer;

- Complete objective response, stable for 5 years, with the Di Bella Method, of multiple-metastatic carcinoma of the breast;

- Evaluation of the safety and efficacy of the first-line treatment with somatostatin combined with melatonin, 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.