ulipristal and Breast-Neoplasms

The purpose of this article is to determine the tumorigenic potential of estradiol treatment (E2) when combined with either progesterone (P4) or medroxyprogesterone acetate (MPA) in normal luminal human breast cells (HBE) and in human breast cancer cells (T47-D, MCF-7). Proliferation profiles were evaluated, along with the gene transactivation activity between the progesterone and glucocorticoid receptors (PR, GR) in HBE, T47-D, and MCF-7 cells treated by E2 + P4 or E2 + MPA. High throughput transcriptome analysis was performed on RNA from HBE cells treated by E2, E2 + MPA and E2 + P4. GR content was analyzed in normal breast cells as well. In HBE cells, E2 + P4 treatment was antiproliferative and promoted cellular differentiation. In contrast, E2 + MPA displayed mitogenic, antiapoptotic effects in HBE cells and did not influence cellular differentiation. The effect of P4 and MPA on cell proliferation was, however, variable in breast cancer cells. In cells containing GR or/and PR, MPA decreased proliferation whereas P4 antiproliferative effect needed the presence of PR. In HBE cells, the regulation of genes by E2 + P4, and E2 + MPA was significantly different, particularly in cell proliferation and cell death gene families. Further analysis revealed a modulation of the glucocorticoid receptor gene expression pathway by E2 + MPA. Predominant MPA glucocorticoid activity in normal and breast cancer cells was demonstrated using a glucocorticoid antagonist and the down-regulation of the GR by RNA interference. In normal luminal breast cells and in breast cancer cells, P4 and MPA combined with E2 treatment have opposing mitogenic effects due to GR. The consequences of MPA glucocorticoid potencies as well as the importance of GR in breast tissue merit a reappraisal.

Topics: Adolescent; Adult; Breast; Breast Neoplasms; Carrier Proteins; Cell Line, Tumor; Cell Proliferation; Estradiol; Female; Gene Expression Profiling; Gene Expression Regulation, Neoplastic; High-Throughput Nucleotide Sequencing; Hormone Replacement Therapy; Humans; Medroxyprogesterone Acetate; Norpregnadienes; Progesterone; Receptors, Estrogen; Receptors, Glucocorticoid; Receptors, Progesterone; RNA Interference; RNA, Small Interfering; Steroids; Transcriptome; Young Adult

It is known that progesterone receptor (PR) isoform A (PR-A) and isoform B (PR-B) may mediate different effects of progesterone. The objective of this study was to determine if the functions of PR isoforms also vary in response to different PR modulators (PRM). The effects of 7 synthetic PRM were tested in MDA-MB-231 cells engineered to express PR-A, PR-B, or both PR isoforms. The effects of progesterone were similar in cells expressing PR-A or PR-B in which it inhibited growth and induced focal adhesion. On the other hand, synthetic PRM modulated the activity of the PR isoforms differently. RU486, CDB4124, 17alpha-hydroxy CDB4124 and VA2914 exerted agonist activities on cell growth and adhesion via PR-B. Via PR-A, however, these compounds displayed agonist effect on cell growth but induced stellate morphology which was distinct from the agonist's effect. Their dual properties via PR-A were also displayed at the gene expression level: the compounds acted as agonists on cell cycle genes but exhibited antagonistic effect on cell adhesion genes. Introduction of ERalpha by adenoviral vector to these cells did not change PR-A or PR-B mediated effect of PRM radically, but it causes significant cell rounding and modified the magnitudes of the responses to PRM. The findings suggest that the activities of PR isoforms may be modulated by different PRM through gene-specific regulatory mechanisms. This raises an interesting possibility that PRM may be designed to be PR isoform and cellular pathway selective to achieve targeted therapy in breast cancer.

Topics: Adenoviridae; Blotting, Western; Breast Neoplasms; Cell Cycle; Cell Division; Collagen; Drug Combinations; Female; Fluorescent Antibody Technique; Hormone Antagonists; Humans; Laminin; Ligands; Mifepristone; Neoplasm Invasiveness; Norpregnadienes; Polymerase Chain Reaction; Progesterone; Protein Isoforms; Proteoglycans; Receptors, Progesterone; Transfection; Tumor Cells, Cultured; Wound Healing