Dataset Information

Differential regulation of breast cancer-associated genes by progesterone receptor isoforms PRA and PRB in a new bi-inducible breast cancer cell line.

ABSTRACT: Progesterone receptor isoforms (PRA and PRB) are expressed at equal levels in normal mammary cells. However, alteration in PRA/PRB expression is often observed in aggressive breast cancer suggesting differential contribution of PR isoforms in carcinogenesis. The mechanisms underlying such processes remain to be established mainly due to paucity of appropriate cellular models. To investigate the role of PR isoforms and the impact of imbalanced PRA/PRB ratio in transcriptional regulation, we have generated an original human breast cancer cell line conditionally expressing PRA and/or PRB in dose-dependence of non-steroid inducers. We first focused on PR-dependent transcriptional regulation of the paracrine growth factor gene amphiregulin (AREG) playing important role in cancer. Interestingly, unliganded PRA increases AREG expression, independently of estrogen receptor, yet inhibitable by antiprogestins. We show that functional outcome of epidermal growth factor (EGF) on such regulation is highly dependent on PRA/PRB ratio. Using this valuable model, genome-wide transcriptomic studies allowed us to determine the differential effects of PRA and PRB as a function of hormonal status. We identified a large number of novel PR-regulated genes notably implicated in breast cancer and metastasis and demonstrated that imbalanced PRA/PRB ratio strongly impact their expression predicting poor outcome in breast cancer. In sum, our unique cell-based system strongly suggests that PRA/PRB ratio is a critical determinant of PR target gene selectivity and responses to hormonal/growth factor stimuli. These findings provide molecular support for the aggressive phenotype of breast cancers with impaired expression of PRA or PRB.

SUBMITTER: Khan JA

PROVIDER: S-EPMC3454371 | biostudies-literature | 2012

REPOSITORIES: biostudies-literature

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Differential regulation of breast cancer-associated genes by progesterone receptor isoforms PRA and PRB in a new bi-inducible breast cancer cell line.

Khan Junaid A JA Bellance Catherine C Guiochon-Mantel Anne A Lombès Marc M Loosfelt Hugues H

PloS one 20120924 9

Progesterone receptor isoforms (PRA and PRB) are expressed at equal levels in normal mammary cells. However, alteration in PRA/PRB expression is often observed in aggressive breast cancer suggesting differential contribution of PR isoforms in carcinogenesis. The mechanisms underlying such processes remain to be established mainly due to paucity of appropriate cellular models. To investigate the role of PR isoforms and the impact of imbalanced PRA/PRB ratio in transcriptional regulation, we have ...[more]

PMID: 23029355

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Project description:The progesterone receptor isoforms PRA and PRB are implicated in breast cancer development and metastasis. Expression ratio PRA/PRB is imbalanced in such cancers under the influence of MAPK-dependent extracellular stimuli that strongly impact progesterone-responsive transcriptional regulation. In order to determine the isoform-specific regulated genes in a metastatic cancer cell, we established the iPRAB cell line derived from MDA-MB-231 mammary cancer cells (ER-, PR-). This cell line conditionally expressed PRA and/or PRB under the control of RSL1 and doxycycline (Dox) non-steroid ligands, respectively, in a dose-dependent manner. The bi-inducible expression system was generated using a combination of the Rheoswitch (NE Biolabs) and T-Rex (Invitrogen) vector systems as described in the article. We investigated the transcriptomes obtained in cells treated by either RSL1 (for PRA), or Dox (for PRB), or RSL1 + Dox (for PRA + PRB) for 24 h and then by either 10 nM progesterone (+) or vehicle (-) for 6 h. Control experiments were obtained from cells grown in the absence of RSL1, doxycycline and in the presence of progesterone (O+) or vehicle (O-). Experimental conditions of PRA/PRB expression ratio were ranged from 0.1 to 10, and the maximum expression of a given isoform was set to 300 fmol per mg proteins following 24 h induction. After removing redundant probes and pseudogens, the processed data identified 1014 distinct regulated genes subdivised in 3 classes : genes responding either only to unliganded PR isoforms (-), or only to liganded (+) or to both conditions (mixed ±). Each classe was subdivided according to isoform specificity criteria (A, B, AB, A&B, A&AB, B&AB, A&B&AB) leading to define 3X7 clusters of genes per classe. Each subset was then further analyzed by complete hierarchical clustering through up or down-regulation criteria. These data indicated that PR target genes selectivity is highly dependent of PRA/PRB expression ratio as well as ligand status and highlight the major impact of PR on transcriptional regulation of genes involved in breast cancer and metastasis.

Project description:The progesterone receptor isoforms PRA and PRB are implicated in breast cancer development and metastasis. Expression ratio PRA/PRB is imbalanced in such cancers under the influence of MAPK-dependent extracellular stimuli that strongly impact progesterone-responsiveM- transcriptional regulation. In order to determine the isoform-specific regulated genes M- in a metastatic cancer cell, we established the iPRAB cell line derived from MDA-MB-231 mammary cancer cells (ER-, PR-). This cell lineM- conditionally expressed PRA and/or PRB under the control of RSL1 and doxycycline (Dox) non-steroid ligands, respectively, in a dose-dependent manner. The bi-inducible expression system was generated using a combination of the Rheoswitch (NE Biolabs) and T-Rex (Invitrogen) vector systems as described in the article. We investigated the transcriptomes obtained in cells treated by either RSL1 (for PRA), or Dox (for PRB), or RSL1 + Dox (for PRA + PRB) for 24 h and then by either 10 nM progesterone (+) or vehicle (-) for 6 h. Control experiments were obtained from cells grown in the absence of RSL1, doxycycline and in the presence of progesterone (O+) or vehicle (O-). Experimental conditions of PRA/PRB expression ratio were ranged from 0.1 to 10, and the maximum expression of a given isoform was set to 300 fmol per mg proteins following 24 h induction. After removing redundant probes and pseudogens, the processed data identified 1014 distinct regulated genes subdivised in 3 classes : genes responding either only to unliganded PR isoforms (-), or only to liganded (+) or to both conditions (mixed M-1). Each classe was subdivided according to isoform specificity criteria (A, B, AB, A&B, A&AB, B&AB, A&B&AB) leading to define 3X7 clusters of genes per classe. Each subset was then further analyzed by complete hierarchical clustering through up or down-regulation criteria. These data indicated that PR target genes selectivity is highly dependent of PRA/PRB expression ratio as well as ligand status and highlight the major impact of PR on transcriptional regulation of genes involved in breast cancer and metastasis.

Dataset Information

Differential regulation of breast cancer-associated genes by progesterone receptor isoforms PRA and PRB in a new bi-inducible breast cancer cell line.

Publications

Differential regulation of breast cancer-associated genes by progesterone receptor isoforms PRA and PRB in a new bi-inducible breast cancer cell line.

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